University Of Houston: The Pressure Is Off And High Temperature Superconductivity Remains - Patch.com | Canada News Media
Connect with us

Science

University Of Houston: The Pressure Is Off And High Temperature Superconductivity Remains – Patch.com

Published

 on


In a critical next step toward room-temperature superconductivity at ambient pressure, Paul Chu, Founding Director and Chief Scientist at the Texas Center for Superconductivity at the University of Houston (TcSUH),  Liangzi Deng, research assistant professor of physics at TcSUH, and their colleagues at TcSUH conceived and developed a pressure-quench (PQ) technique that retains the pressure-enhanced and/or -induced high transition temperature (Tc) phase even after the removal of the applied pressure that generates this phase.

Pengcheng Dai, professor of physics and astronomy at Rice University and his group, and Yanming Ma, Dean of the College of Physics at Jilin University, and his group contributed toward successfully demonstrating the possibility of the pressure-quench technique in a model high temperature superconductor, iron selenide (FeSe). The results were published in the journal  Proceedings of the National Academy of Science USA­­­.

“We derived the pressure-quench method from the formation of the man-made diamond by Francis Bundy from graphite in 1955 and other metastable compounds,” said Chu. “Graphite turns into a diamond when subjected to high pressure at high temperatures. Subsequent rapid pressure quench, or removal of pressure, leaves the diamond phase intact without pressure.”

Chu and his team applied this same concept to a superconducting material with promising results.

“Iron selenide is considered a simple high-temperature superconductor with a transition temperature (Tc) for transitioning to a superconductive state at 9 Kelvin (K) at ambient pressure,” said Chu.

“When we applied pressure, the Tc increased to ~ 40 K, more than quadrupling that at ambient, enabling us to unambiguously distinguish the superconducting PQ phase from the original un-PQ phase. We then tried to retain the high-pressure enhanced superconducting phase after removing pressure using the PQ method, and it turns out we can.”

Dr. Chu and colleagues’ achievement brings scientists a step closer to realizing the dream of room-temperature superconductivity at ambient pressure, recently reported in hydrides only under extremely high pressure.

Superconductivity is a phenomenon discovered in 1911 by Heike Kamerlingh Onnes by cooling mercury below its transition Tc of 4.2 K, attainable with the aid of liquid helium, which is rare and expensive. The phenomenon is profound because of superconductor’s ability to exhibit zero resistance when electricity moves through a superconducting wire and its expulsion of magnetic field generated by a magnet. Subsequently, its vast potential in the energy and transportation sectors was immediately recognized.

To operate a superconducting device, one needs to cool it to below its Tc, which requires energy. The higher the Tc, the less energy needed. Therefore, raising the Tc with the ultimate goal of room temperature of 300 K has been the driving force for scientists in superconductivity research since its discovery.

In defiance of the then-prevailing belief that Tc could not exceed the 30’s K, Paul Chu , and colleagues discovered superconductivity in a new family of compounds at 93 K in 1987, achievable by the mere use of the inexpensive, cost-effective industrial coolant of liquid nitrogen. The Tc has continuously been raised since to 164 K by Chu et al. and other subsequent groups of scientists. Recently a Tc  of 287 K was achieved by Dias et al. of Rochester University in carbon-hydrogen-sulfide under 267 gigapascal (GPa).

In short, the advancement of Tc to room temperature is indeed within reach. But for future scientific and technological development of hydrides, characterization of materials and fabrication of devices at ambient pressures is necessary.

“Our method allows us to make the material superconducting with higher Tc without pressure. It even allows us to retain at ambient the non-superconducting phase that exists only in FeSe above 8 GPa. There is no reason that the technique cannot be equally applied to the hydrides that have shown signs of superconductivity with a Tc approaching room temperature.”

The achievement inches the academic community closer toward room-temperature superconductivity (RTS) without pressure, which would mean ubiquitous practical applications for superconductors from the medical field, through power transmission and storage to transportation, with impacts whenever electricity is used. 

Superconductivity as a means to improve power generation, storage and transmission is not a new idea, but it requires further research and development to become widespread before room temperature superconductivity becomes a reality. The capacity for zero electrical resistance means energy can be generated, transmitted and stored with no loss – an enormous low-cost advantage. However, current technology demands that the superconducting device be kept at severely low temperatures to retain its unique state, which still requires additional energy as an overhead cost, not to mention the potential hazard of the accidental failure of the cooling system. Hence, an RTS superconductor with no extra pressure to sustain its beneficial properties is a necessity to move forward with more practical applications.

The properties of superconductivity are also paving the way for a competitor to the famous bullet train seen throughout East Asia: a maglev train. Short for “magnetic levitation,” the first maglev train built in Shanghai in 2004 successfully broadened usage in Japan and South Korea and is under consideration for commercial operation in the US. At top speeds of 375 miles per hour, cross country flights see a quick competitor in the maglev train. A room temperature superconductor could help Elon Musk realize his dream of a “hyperloop” to travel at a speed of 1000 miles per hour.

This successful implementation of the PQ technique on room temperature superconductors discussed in Chu and Deng’s paper is critical in making superconductors possible for ubiquitous practical applications.

Now the riddle of RTS at ambient pressure is even closer to being solved.


This press release was produced by the University of Houston. The views expressed here are the author’s own.

Adblock test (Why?)



Source link

Continue Reading

Science

The body of a Ugandan Olympic athlete who was set on fire by her partner is received by family

Published

 on

 

NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.

Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.

She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.

Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.

“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.

It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.

Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.

Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.

Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.

“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.

He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.

Kenya’s high rates of violence against women have prompted marches by ordinary citizens in towns and cities this year.

Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.

The Canadian Press. All rights reserved.

Source link

Continue Reading

News

The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

Published

 on

 

TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.

Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.

Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.

The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.

The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.

It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.

Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.

Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.

Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.

Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.

Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.

The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”

The Canadian Press. All rights reserved.

Source link

Continue Reading

News

B.C. sets up a panel on bear deaths, will review conservation officer training

Published

 on

 

VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.

Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”

Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.

“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.

B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.

Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.

Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.

Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.

“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”

Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”

“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.

Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.

“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.

This report by The Canadian Press was first published Sept. 9, 2024.

The Canadian Press. All rights reserved.

Source link

Continue Reading

Trending

Exit mobile version