Radiation from Router

[CYRN]

pls change the thread title to Radiation 101 or FAQ on Radiation or everything u want to know abt radiation but dont know what to ask.

v informative:thumbsup:

you learn best by joining... :devil:

 

[LittleWolf]

Dude, don't evade the question. Your statements:

"Classical example, from a post above, is a handphone in the car - the RF energy gets largely trapped in the metal chassis, increasing exposure of the driver/passengers. On top of that, the phone will increase its transmission power to stay in contact with the base from which it is shielded by the car."

"There is not a single mechanism for mutations. RF exposure can also result in mutations. The most direct effect of RF is heating of tissue, which can knock the biochemistry out of its normal regime, which can potentially lead to mutations as well."

So, 3rd time asking, what is the usual rise in human tissue temperature due to typical handphone radiation?

I don't know what's "usual", but one can take a look at the literature. There are probably thousands of articles on the topic, so I'm just skimming through a few.

Estimates vary, and they would actually depend a lot on the position in which the phone is used (i.e. where the antenna is). On the lower end, [1] estimates a temperature increase of 0.11 K in the brain at 2 W/kg SAR (specific absorption rate). Note though that the brain is fairly efficiently cooled by blood circulation; there may be more concern for the eye (0.35 K temperature increase at a SAR of 2 W/kg [2]), also in the light that traditionally, a link between eye exposure to RF and formation of cataracts is assumed (while this is disputed by some, I had a middle aged colleague working with low-power microwave equipment who had to undergo cataract surgery). An interesting paper [3] considers the effect of usually neglected metallic objects, namely spectacles, and reports an increase of the eye SAR by up to 160%.

The SAR is usually based on averaging over 10 g of tissue. This might give an optimistic picture: [4], which averages over 1 g of tissue (and therefore better reflects "hot spots"), mentions a SAR of a whopping 3.7 W/kg for one phone model (I believe the permissible limits depend on legislation; but this is more than twice the FCC's limit of 1.6 W/kg [5]), and estimates a maximum temperature rise in brain tissue of 0.16 K per 1 W/kg SAR.

It's interesting that this topic seems to be discussed mostly in engineering journals. On the other hand, there's a plethora of articles claiming non-thermal effects in biology/medical journals, but those typically appear rather dubious. An example is [6] which claims mutations caused by RF irradiation of human tissue at 1.8 GHz and an SAR of 3 W/kg.


[1] Wang J et al, IEEE Transact Microwave Theory & Techniques 47(8), 1528 (1999)
[2] Hirata A, IEEE Transact Electromag Compat 47(1), 68 (2005)
[3] Whittow WG et al, IEEE Transact Ant Propag 52(120), 3207 (2004)
[4] Bernardi P et al, IEEE Transact Microwave Theory & Techniques 48(7), 1118 (2000)
[5] Cleveland RF et al, FCC OET Bulletin 56
[6] Sun L et al, Mutation Res. 602(1-2), 135 (2006)

 

[CYRN]

[1] Wang J et al, IEEE Transact Microwave Theory & Techniques 47(8), 1528 (1999)
[2] Hirata A, IEEE Transact Electromag Compat 47(1), 68 (2005)
[3] Whittow WG et al, IEEE Transact Ant Propag 52(120), 3207 (2004)
[4] Bernardi P et al, IEEE Transact Microwave Theory & Techniques 48(7), 1118 (2000)
[5] Cleveland RF et al, FCC OET Bulletin 56
[6] Sun L et al, Mutation Res. 602(1-2), 135 (2006)

mind providing the link?

can't find from google.

thanks

 

[LittleWolf]

mind providing the link?

can't find from google.

[1] Wang J et al, IEEE Transact Microwave Theory & Techniques 47(8), 1528 (1999)
http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=22

[2] Hirata A, IEEE Transact Electromag Compat 47(1), 68 (2005)
http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=15

[3] Whittow WG et al, IEEE Transact Ant Propag 52(120), 3207 (2004)
http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=8

[4] Bernardi P et al, IEEE Transact Microwave Theory & Techniques 48(7), 1118 (2000)
see [1]

[5] Cleveland RF et al, FCC OET Bulletin 56
http://www.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet56/oet56e4.pdf

[6] Sun L et al, Mutation Res. 602(1-2), 135 (2006)
http://www.sciencedirect.com/science/journal/00275107

 

[CYRN]

[1] Wang J et al, IEEE Transact Microwave Theory & Techniques 47(8), 1528 (1999)
http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=22

[2] Hirata A, IEEE Transact Electromag Compat 47(1), 68 (2005)
http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=15

[3] Whittow WG et al, IEEE Transact Ant Propag 52(120), 3207 (2004)
http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=8

[4] Bernardi P et al, IEEE Transact Microwave Theory & Techniques 48(7), 1118 (2000)
see [1]

[5] Cleveland RF et al, FCC OET Bulletin 56
http://www.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet56/oet56e4.pdf

[6] Sun L et al, Mutation Res. 602(1-2), 135 (2006)
http://www.sciencedirect.com/science/journal/00275107

onli can access the FCC one... the rest cannot see article... :cry:

are you a subscriber to IEEE?

 

[Giorgio]

ya...

.. so I ask you to examine what's flawed with the below quote...



since you mention on no grounds any can determine how much before one gets cancer (or not)?

*edit* add a side note...
UV is also non-ionising

For weak EMW,there is hardly any groud to determine whether it can result in cancer.
Ionizing radiation however,well,that you can be sure.

The edvidence of ionizing radiation used in chemo is a very good example itself.
Exposure to it instantly kill cells and damage the DNA blueprint.

 

[Kermitfm]

Why are we having such arguments.? Because the evidence is still inconclusive even among the experts and top brains.

See : zdnetasia news (Sept 2008) - Cell Phones and Cancers : More research Needed

Ai-yah, this is a kopitiam lah. Relak and have a cuppa. Kopi-o sui dai please.

 

[hazmee]

They are all very relaxed la. It's a love and hate relationship.

 

[LittleWolf]

onli can access the FCC one... the rest cannot see article... :cry:

The abstracts are freely accessible, though.

are you a subscriber to IEEE?

Personally, no. Indirectly, yes.

 

[ArchRival]

I don't know what's "usual", but one can take a look at the literature. There are probably thousands of articles on the topic, so I'm just skimming through a few.

Estimates vary, and they would actually depend a lot on the position in which the phone is used (i.e. where the antenna is). On the lower end, [1] estimates a temperature increase of 0.11 K in the brain at 2 W/kg SAR (specific absorption rate). Note though that the brain is fairly efficiently cooled by blood circulation; there may be more concern for the eye (0.35 K temperature increase at a SAR of 2 W/kg [2]), also in the light that traditionally, a link between eye exposure to RF and formation of cataracts is assumed (while this is disputed by some, I had a middle aged colleague working with low-power microwave equipment who had to undergo cataract surgery). An interesting paper [3] considers the effect of usually neglected metallic objects, namely spectacles, and reports an increase of the eye SAR by up to 160%.

The SAR is usually based on averaging over 10 g of tissue. This might give an optimistic picture: [4], which averages over 1 g of tissue (and therefore better reflects "hot spots"), mentions a SAR of a whopping 3.7 W/kg for one phone model (I believe the permissible limits depend on legislation; but this is more than twice the FCC's limit of 1.6 W/kg [5]), and estimates a maximum temperature rise in brain tissue of 0.16 K per 1 W/kg SAR.

It's interesting that this topic seems to be discussed mostly in engineering journals. On the other hand, there's a plethora of articles claiming non-thermal effects in biology/medical journals, but those typically appear rather dubious. An example is [6] which claims mutations caused by RF irradiation of human tissue at 1.8 GHz and an SAR of 3 W/kg.


[1] Wang J et al, IEEE Transact Microwave Theory & Techniques 47(8), 1528 (1999)
[2] Hirata A, IEEE Transact Electromag Compat 47(1), 68 (2005)
[3] Whittow WG et al, IEEE Transact Ant Propag 52(120), 3207 (2004)
[4] Bernardi P et al, IEEE Transact Microwave Theory & Techniques 48(7), 1118 (2000)
[5] Cleveland RF et al, FCC OET Bulletin 56
[6] Sun L et al, Mutation Res. 602(1-2), 135 (2006)

Very good. We know the body is capable of maintaining temperature within a very specific range. Given that temperature is an active process, do you think equation 1 in [1] and/or equation 2 in [2] is adequate?

 

[CYRN]

For weak EMW,there is hardly any groud to determine whether it can result in cancer.
Ionizing radiation however,well,that you can be sure.

The edvidence of ionizing radiation used in chemo is a very good example itself.
Exposure to it instantly kill cells and damage the DNA blueprint.

Why are we having such arguments.? Because the evidence is still inconclusive even among the experts and top brains.

See : zdnetasia news (Sept 2008) - Cell Phones and Cancers : More research Needed

Ai-yah, this is a kopitiam lah. Relak and have a cuppa. Kopi-o sui dai please.

They are all very relaxed la. It's a love and hate relationship.

Paiseh! fly aeloplane.. so no online...

hazmee's is right-on... this is relaxed kopitiam tok... everione here to hav fun to provide entertainment for those reading these threads with pop-corns and cokes prepared.

aniway... I'm trying to say it's inconclusive... but if anione insist to conclude it... then let him conclude loh.

Chinese New Year liao... time HUAT AH! No time to debate for the next few days... :cry:

as someone posted.. what's the point of getting heated over some text on the screen... I'll leave the heating to microwaves.

 

[CYRN]

The abstracts are freely accessible, though.



Personally, no. Indirectly, yes.

oic.. mabbe I need click on wrong thing..will try again.. thanks.

 

[Pablo]

Oh my gdd,
I have been reading this thread from the start.

Now I have developed (what I believe is caused by radiation) a second; no; 3rd HEAD !!.

From what my friend in NASSA tels me, it is due to thread radiation.

Also caused by my cellphone showing graphic images :bigeyes:

As such, please close this thread and stop sending me (via SMS) rude photo's