Many women and some men are very particular about their hair. One of the ways for keeping it in shape involves applying heat, but just how much of it and for how long has been mostly left to experience. A scientist from Purdue University, Indiana, is trying to find a scientific answer.

Some people who have naturally curly hair prefer to have it straightened.
Others with straight hair want to have curls.
"It is kind of like the way I see the world, like the lens through which I see the world and I always was wondering about how we can think about this from a mechanical engineering perspective," explains Tahira Reid, assistant professor of Mechanical Engineering at Purdue University.
Hair irons can take many shapes but are essentially clips or rods with heated surfaces.
"If you go to the mall right now you see an aisle full of straightening irons, and they have terms like ion technology and twirling," notes Amy Marconnet, also an Assistant Professor of Mechanical Engineering at Purdue University.
The heat weakens or breaks a protein called keratin, responsible for the hair's shape, and temporarily changes it. But nobody knows exactly at what level the heat can actually cause permanent damage.
"If we understand the onset at which that happens than we might be able to intervene before or give some suggestions before you get to that point," Reid says.
Inside a Purdue University lab, a movable flat hair iron goes over a hair strand while an infrared microscope measures the changes in the hair's structure.
Researchers say early results are a bit inconclusive. It turns out that everyone's hair is different and that there's no exact temperature where hair straightening becomes hair damage. For example, people with naturally curly hair can suffer more damage from heat irons than those with straight hair.
Reid says they will continue their research in the hopes of finding that heat sweet spot for stylists.
国际英语资讯:Opposition parties barred from elections in Venezuela
国际英语资讯:Syrian army captures last IS stronghold in Homs province
国际英语资讯:Britain to have transitional period after leaving the EU: ministers
国际英语资讯:Spotlight: Battle to break siege on Syrias Deir al-Zour imminent as IS loses Al-Sukhnah ci
体坛英语资讯:Gong wins Chinas first gold medal, surprise victories for Warholm and Francis
体坛英语资讯:Frenchman Bosse crowned mens 800m world champion (updated)
国际英语资讯:Austria to tighten border controls due to increase in illegal migration
国际英语资讯:Economic reforms in Serbia reflected in booming trade with Netherlands: Dutch FM
国际英语资讯:Iran adopts economic diplomacy as key foreign policy
国际英语资讯:UN chief urges Venezuelans to ease tensions, engage in negotiations
国际英语资讯:China continues to see slowdown in luxury goods spending: report
国际英语资讯:At least one dead in car crash after violent rally in Virginia, U.S.
国际英语资讯:1 in 4 U.S. voters think Trumps dealings with Russia illegal during campaign: poll
体坛英语资讯:Ronaldinho sets condition for return to football
国际英语资讯:Investigation reopens against Brazilian former president Lula
国际英语资讯:ASEAN foreign ministers commend Chinas regional role
国际英语资讯:Young versus old, new divide in Brexit Britain
国际英语资讯:Syria urges UN to dissolve U.S.-led coalition over crimes against civilians
国际英语资讯:Spotlight: Chinese Americans divided on Trumps new immigration bill
国际英语资讯:Britain denies agreeing to multi-billion under Brexit divorce bill
国际英语资讯:U.S. federal court rules in favor of Chinese businesswoman beaten by border agent in 2004
国际英语资讯:Nearly 1.6 mln Ukrainians displaced as conflict enters 4th year: UNHCR
国际英语资讯:Silence, speech, song at San Franciscos vigil for Charlottesville victims
体坛英语资讯:World record holder Lavillenie happy after taking mens pole vault bronze
国际英语资讯:German startups expect better business in next six months: Study
国际英语资讯:Chinas mobile apps exceed 4.02 mln
国际英语资讯:Indian army says five militants killed on Kashmir LoC
国际英语资讯:France urges DRRK to comply with obligations, prevent further tensions
国际英语资讯:Commentary: Britain takes step to protect personal data in digital era
国际英语资讯:Sisi reiterates need for Qatar to respond to Arab quartets concerns
| 不限 |
| 英语教案 |
| 英语课件 |
| 英语试题 |
| 不限 |
| 不限 |
| 上册 |
| 下册 |
| 不限 |