(THIS ARTICLE IS COURTESY OF NPR NEWS)
Researchers have identified a metal that conducts electricity without conducting heat – an incredibly useful property that defies our current understanding of how conductors work.
The metal, found in 2017, contradicts something called the Wiedemann-Franz Law, which basically states that good conductors of electricity will also be proportionally good conductors of heat, which is why things like motors and appliances get so hot when you use them regularly.
But a team in the US showed this isn’t the case for metallic vanadium dioxide (VO2) – a material that’s already well known for its strange ability to switch from a see-through insulator to a conductive metal at the temperature of 67 degrees Celsius (152 degrees Fahrenheit).
“This was a totally unexpected finding,” said lead researcher Junqiao Wu from Berkeley Lab’s Materials Sciences Division back in January 2017.
“It shows a drastic breakdown of a textbook law that has been known to be robust for conventional conductors. This discovery is of fundamental importance for understanding the basic electronic behavior of novel conductors.”
Not only does this unexpected property change what we know about conductors, it could also be incredibly useful – the metal could one day be used to convert wasted heat from engines and appliances back into electricity, or even create better window coverings that keep buildings cool.
Researchers already knew of a handful of other materials that conduct electricity better than heat, but they only display those properties at temperatures hundreds of degrees below zero, which makes them highly impractical for any real-world applications.
Vanadium dioxide, on the other hand, is usually only a conductor at warm temperatures well above room temperature, which means it has the ability to be a lot more practical.
To uncover this bizarre property, the team looked at the way that electrons move within vanadium dioxide’s crystal lattice, as well as how much heat was being generated.
Surprisingly, they found that the thermal conductivity that could be attributed to the electrons in the material was 10 times smaller than that amount predicted by the Wiedemann-Franz Law.
The reason for this appears to be the synchronised way that the electrons move through the material.
“The electrons were moving in unison with each other, much like a fluid, instead of as individual particles like in normal metals,” said Wu.
“For electrons, heat is a random motion. Normal metals transport heat efficiently because there are so many different possible microscopic configurations that the individual electrons can jump between.”
“In contrast, the coordinated, marching-band-like motion of electrons in vanadium dioxide is detrimental to heat transfer as there are fewer configurations available for the electrons to hop randomly between,” he added.
Interestingly, when the researchers mixed the vanadium dioxide with other materials, they could ‘tune’ the amount of both electricity and heat that it could conduct – which could be incredibly useful for future applications.
For example, when the researchers added the metal tungsten to vanadium dioxide, they lowered the temperature at which the material became metallic, and also made it a better heat conductor.
That means that vanadium dioxide could help dissipate heat from a system, by only conducting heat when it hits a certain temperature. Before that it would be an insulator.
Vanadium dioxide also has the unique ability of being transparent to around 30 degrees Celsius (86 degrees Fahrenheit), but then reflects infrared light above 60 degrees Celsius (140 degrees Fahrenheit) while remaining transparent to visible light.
So that means it could even be used as a window coating that reduces the temperature without the need for air conditioning.
“This material could be used to help stabilize temperature,” said one of the researchers, Fan Yang.
“By tuning its thermal conductivity, the material can efficiently and automatically dissipate heat in the hot summer because it will have high thermal conductivity, but prevent heat loss in the cold winter because of its low thermal conductivity at lower temperatures.”
A lot more research needs to be done on this puzzling material before it’s commercialized further, but it’s pretty exciting that we now know these bizarre properties exist in a material at room temperature.
The research was published in Science in 2017.
A version of this article was first published in January 2017.
Initially, the line would import 500 megawatts of electricity to its overstretched grid by 2020 and in competitive Gulf market prices, revealed the Iraqi Electricity Ministry.
The 300-kilometer transmission line would run from Kuwait to Iraq’s southern port of Faw and be financed by the GCC IA, according to the ministry.
Electricity Minister Luay al-Khateeb signed the deal, which comes amid other agreements signed with huge western firms under the strategy adopted by the ministry to reform and develop the sector, which has been suffering from a deteriorating power supply.
Iraq partly fills its power shortages by importing both electricity and natural gas from Iran.
Musab al-Mudarres, the spokesperson for the Iraqi Electricity Ministry, told Asharq Al-Awsat newspaper that Iraq seeks to become a promising market for energy by networking with the Gulf system and importing 500 megawatts by 2020, and being the link between the Gulf energy system and Europe’s.
Mudarres stressed that the ministry is working on a road map set to revitalize the energy sector, which depends on the assistance of giant firms such as General Electric (GE) and Siemens.
As for the volume of generated electricity and the target output of the ministry, the spokesperson said that Iraq has a power capacity of around 18,000 megawatts, including the amount imported through Iranian lines. But the ministry aims for 30,000 megawatts in the coming three to four years.
On Saturday, the ministry signed deals with Siemens and Orascom Construction to rebuild two power plants. Also, GE signed a new agreement with Mass Energy Group Holding (MGH) to help boost electricity generation to 4.5 megawatts.
“Electricity is a national security issue,” Luay al-Khateeb told AFP in a wide-ranging interview at the ministry’s headquarters in Baghdad.
“In the end, any political, economic or security crisis in Iraq will affect the whole region — and the global economy will be open to threat.”
“We’re urging for this file not to be politicized.”
Khateeb, a 51-year-old energy expert, was appointed minister in October with a mandate to revamp Iraq’s grid, which was already ailing before it was further crippled by the ISIS group.
But he faces a pair of formidable political challenges to a typically dry, technical portfolio: the threat of renewed protests and escalating US pressure on energy-supplier Iran.
Demonstrations erupted in 2018 across Iraq against poor services, including the measly few hours of state-provided electricity per day.
This summer will be a de facto referendum on the government´s progress.
Khateeb, optimistic, said his ministry had revived out-of-service stations, fixed transmission lines, and brought temporary generators to battered areas including Mosul that ISIS held in the north.
“On October 25, the week I took office, electricity generation sat at between 9.5 to 10 GW. It is now at 15 GW,” Khateeb said.
Most Iraqi provinces, he added, “will receive no less than 20 hours of electricity per day. This, to be honest, is a level of production the country hasn’t seen in years.”
In the medium term, the ministry is developing solar power, gas-capturing capabilities, and energy deals with neighbors.
It signed contracts worth 700 million euro ($785 million) with Germany’s Siemens last month, amid expectations of similar deals with American rival General Electric.
Around a third of Iraq’s electricity relies on Iran, through 28 million cubic meters (990 cubic feet) of gas piped in to feed stations or the direct import of up to 1,300 megawatts of Iranian-produced electricity.
When Washington reimposed sanctions on Iran last year, it granted Iraq temporary exemptions until late June.
Khateeb declined to say what would happen if the waiver was not again extended.
“I’m not in the business of making predictions, but what I ask for from world powers is a little reasonableness so we can live in peace on this planet,” he told AFP.
Tensions have ramped up between Washington and Tehran, with Baghdad often caught in the middle.
Iraqi government sources say the US is pressuring Baghdad to partner with American companies including General Electric, ExxonMobil and Honeywell as it weans off Iranian energy.
Khateeb acknowledged foreign embassies were pushing for their interests in Iraq’s power sector, but said Baghdad would try to steer clear of the politics.
“The truth is we don’t want to be a scapegoat in conflicts that will negatively affect regional security, and in turn the global economy,” he said.
Besides the ticking clocks of the Iraqi street and geopolitical tensions, Khateeb admitted pressure from within the government itself.
He said he had “inherited a bureaucracy” and was often asked for favors or employment opportunities.
Asked whether he, like Prime Minister Adel Abdul Mahdi, kept his resignation letter close at hand, Khateeb sounded determined.
“One needs to have a thick skin,” he said.
“Either I focus on the politicians, or I focus on the work.”
Spreading calm and positivity through this blog
Creating with twist..
Travel, Career, Lifestyle
I'm a Doctor with so many random thoughts, so I decided to blog. This blog is mostly dedicated to health, movies, management & motivational mini posts. Enjoy :-)
Success Stories for Angsty Professionals
Wonderings about the meaning of existence.
Surviving the 21st century
Educator. Poet. Self-Help Writer.