Electromagnetic Interference / Compatibility

gals2

LOW FREQUENCY ELECTRIC FIELD

--- cth low freq ni mcm transmision line.. tu mcm gamba kat atas tu.. ( ni kita selalu tgk kan.. biasa kat area2 bukit2 kawasan2 highway.. yg jarang ada penduduk) tapiiiiiiiiiiiiiiii... ada je kat kawasan perumahan atau shoping komplex..    ni satu kesalahan ni sebab dia ada jarak2 tertentu tuk letak transmision line ni... sebab selain ada kesan kat human.. ada gak kesan kat kereta2 yg ada electronic control.. and brg2 elektrik yg len.. :kant:


influence the human body just as they influence any other material made up of charged particles. When electric fields act on conductive materials, they influence the distribution of electric charges at their surface. They cause current to flow through the body to the ground.
Low-frequency magnetic fields induce circulating currents within the human body. The strength of these currents depends on the intensity of the outside magnetic field. If sufficiently large, these currents could cause stimulation of nerves and muscles or affect other biological processes.
Both electric and magnetic fields induce voltages and currents in the body but even directly beneath a high voltage transmission line, the induced currents are very small compared to thresholds for producing shock and other electrical effects.

Heating is the main biological effect of the electromagnetic fields of radiofrequency fields. In microwave ovens this fact is employed to warm up food. The levels of radiofrequency fields to which people are normally exposed are very much lower than those needed to produce significant heating. The heating effect of radiowaves forms the underlying basis for current guidelines. Scientists are also investigating the possibility that effects below the threshold level for body heating occur as a result of long-term exposure. To date, no adverse health effects from low level, long-term exposure to radiofrequency or power frequency fields have been confirmed, but scientists are actively continuing to research this area.

gals2

Biological effects or health effects? What is a health hazard?

Biological effects are measurable responses to a stimulus or to a change in the environment. These changes are not necessarily harmful to your health. For ex
ample, listening to music, reading a book, eating an apple or playing tennis will produce a range of biological effects. Nevertheless, none of these activities is ex
pected to cause health effects. The body has sophisticated mechanisms to adjust to the many and varied influences we encounter in our environment. Ongoing change forms a normal part of our lives. But, of course, the body does not possess adequate compensation mechanisms for all biological effects. Changes that are irreversible and stress the system for long periods of time may constitute a health hazard.

An adverse health effect causes detectable impairment of the health of the exposed individual or of his or her offspring; a biological effect, on the other hand, may or may not result in an adverse health effect.

It is not disputed that electromagnetic fields above certain levels can trigger biological effects. Experiments with healthy volunteers indicate that short-term exposure at the levels present in the environment or in the home do not cause any apparent detrimental effects. Exposures to higher levels that might be harmful are restricted by national and international guidelines. The current debate is centred on whether long-term low level exposure can evoke biological responses and influence people's well being.Widespread concerns for health

A look at the news headlines of recent years allows some insight into the various areas of public concern. Over the course of the past decade, numerous electromagnetic field sources have become the focus of health concerns, including power lines, microwave ovens, computer and TV screens, security devices, radars and most recently mobile phones and their base stations.





Setiap malam kalau aku tido kan.. biasa aku mmg pakai handphone as a alarm.. tapi tiap2 malam aku takut..  :kant:  lately aku mmg campak jauh2 handpon aku masa nak tido.. tapi kdg2 dah takde sgt alarm.. tarok gak kat sebelah.. bgn pagi rasa cam takut je.. huk2.. aku duduk sebelah microwave oven pun takut..

:no:  jgn duduk dekat2 ngan microwave oven masa kita dah on microwave tu.. kalau dok jauh2 takpe.. sebab wave ni bila dlm jarak2 tertentu dia akan berkurangan..  :bgrin:  its ok je kalau nak guna.. tapi jgn dok intai2 lama2 sampai berjam2 masa tgh masak tu.. tapi.. kalau sekejap idak ler kasik effect sgt2..

tapi semua nya masih dlm research.. sedangkan aku pun tgh survey2 reserch camne nak design bagus nya enclosure and cabelling.. :jeling:

[ Last edited by  gals2 at 11-1-2007 10:34 AM ]

gals2

Conclusions from scientific research

In the area of biological effects and medical applications of non-ionizing radiation approximately 25,000 articles have been published over the past 30 years. Despite the feeling of some people that more research needs to be done, scientific knowledge in this area is now more extensive than for most chemicals. Based on a recent in-depth review of the scientific literature, the WHO concluded that current evidence does not confirm the existence of any health consequences from exposure to low level electromagnetic fields. However, some gaps in knowledge about biological effects exist and need further research.

gals2

Effects on general health

Ada kajian yg dijalankan mengatakan ada yg effect pada kat umah. antara symptoms2 akibat effect EMW ni:  headaches, anxiety, suicide and depression, nausea, fatigue and loss of libido.

TAPI: To date, scientific evidence does not support a link between these symptoms and exposure to electromagnetic fields.
Sebab---> kdg2 may be its caused by noise or faktor len kat enviroment kita ni.:jeling: or by anxiety related to the presence of new technologies.

gals2

Effects on pregnancy outcome

Banyak punca2 radiation EM ni.. termasukla --->computer screens, water beds and electric blankets, radiofrequency welding machines, diathermy equipment and radar, have been evaluated by the WHO and other organizations.

tapi.. from research :hmm:  

The overall weight of evidence shows that exposure to fields at typical environmental levels does not increase the risk of any adverse outcome such as spontaneous abortions, malformations, low birth weight, and congenital diseases. There have been occasional reports of associations between health problems and presumed exposure to electromagnetic fields, such as reports of prematurity and low birth weight in children of workers in the electronics industry, but these have not been regarded by the scientific community as being necessarily caused by the field exposures (as opposed to factors such as exposure to solvents).

gals2

Cataracts
General eye irritation and cataracts have sometimes been reported in workers exposed to high levels of radiofrequency and microwave radiation, but animal studies do not support the idea that such forms of eye damage can be produced at levels that are not thermally hazardous. There is no evidence that these effects occur at levels experienced by the general public.

jgn lupa bc post yg sebelum ni  :nerd:

gals2

Electromagnetic fields and cancer
Despite many studies, the evidence for any effect remains highly controversial. However, it is clear that if electromagnetic fields do have an effect on cancer, then any increase in risk will be extremely small. The results to date contain many inconsistencies, but no large increases in risk have been found for any cancer in children or adults.

A number of epidemiological studies suggest small increases in risk of childhood leukemia with exposure to low frequency magnetic fields in the home. However, scientists have not generally concluded that these results indicate a cause-effect relation between exposure to the fields and disease (as opposed to artifacts in the study or effects unrelated to field exposure). In part, this conclusion has been reached because animal and laboratory studies fail to demonstrate any reproducible effects that are consistent with the hypothesis that fields cause or promote cancer. Large-scale studies are currently underway in several countries and may help resolve these issues.

gals2

Electromagnetic hypersensitivity and depression



Some individuals report "hypersensitivity" to electric or magnetic fields. They ask whether aches and pains, headaches, depression, lethargy, sleeping disorders, and even convulsions and epileptic seizures could be associated with electromagnetic field exposure.

There is little scientific evidence to support the idea of electromagnetic hypersensitivity. Recent Scandinavian studies found that individuals do not show consistent reactions under properly controlled conditions of electromagnetic field exposure. Nor is there any accepted biological mechanism to explain hypersensitivity. Research on this subject is difficult because many other subjective responses may be involved, apart from direct effects of fields themselves. More studies are continuing on the subject.

wa'ah

what will be the unit to measure electromagnetic field?

leyna

saye ade kene wat mini projek pasal aplikasi/sistem yg menggunakan teori  elektromagnet..
ade sesape boleh bg pandangan?

gals2

skop nya mcm mana? ni nak kena uat real aplication atau just pembentangan jer?

leyna

buat pembentangan je.
ni soalan die..
2.1.        Topic range

gals2

kenapa aku rasa mcm aku pernah dpt je assignment nih...

tpi tu zaman dulu2 ar..

banyak gak application dia.. cth nya kan.. mcm BOM EMT ke.. tapi ni masih dlm kajian nih kat malaysia..
lagi apa yer..

gals2

banyak sebenarnya.. tapi tak terfikir plak kali nih..

oo cth len.. kita uat alat tuk make sure banduan dlm penjara tak dpt larikan diri..

cth nya:  semua banduan pakai satu alat kat bdn dia... then kat sekeliling dinding penjara ada alat gak.. bila banduan tuh mendekati dinding di mana ada pengesan di situ...that ssensor akan antar siyarat supaya EMW aktif dan menyebabkan banduan melekat pada dinding.. bunyik mcm kelakar kan.. tapi kalau pikir bebetul leh masuk kan teori mcm maxwell equation ke.. apa2 kaitan ngan TEORI EMT.. ni nak EMT kan...  leh terangkan berdasarkan teori dia..

len2  apa ye..

leyna

thanks gals...
nak cbe bincang dlu ngan group member aku...
aku baru je blaja emt ni..
baru first chap..
pasal vector..
maxwell equation pun aku lum jumpe lagi...
da nak suro aku wat mini pojek..

gals2

memang.. aku dulu pun cenggitu gak... vector eh.. aku plak next week nak kena ngajar tutorial vector.. baru lepas siap soklan ngan skema.. ko guna buku rujukan pe tuk stadi?

leyna

fundamental of electromagnetics with engineering applications..
stuart m.wentworth..
tapi aku lum bli lagi...
note sumer lec bg..
rupenyer aku kene wat bende yg simple je la gals..
cam transformer ke,mic ke,electric generator..
tapi aku bkn nyer terer sgt wat mini pojek ni...

oobi

wow! dah lama oobi tak sentuh subjek ni. lama dah tinggalkan. masabelajar dulu, malas nak baca. bila dah lama tinggalkan, menarik pulak. :nyorok:

leyna

bole la ko bg aku cth soalan tg ko dah wat tu?
bole la..

gals2

sori lambat reply.. cth soklan yg mana? aku guna buku elements of electromagnetics third edition matthew N.O sadiku... buku ni bagus uat rujukan neh..   senang nak paham.. then... aku ada semua jawapan dia..  siap skema lagi