Law governing anomalous heat conduction revealed
Study finds the law governing how heat transport scales up with temperature
2015-07-14
(Press-News.org) How heat travels, matters. Yet, there is still no consensus on the exact physical mechanism that causes anomalous heat conduction - despite the existence of previous numerical simulation, theoretical predictions and experimental observations. Now, a team based in Asia has demonstrated that electron transport depends on temperature. It follows a scaling governed by a power law - and not the exponential scaling previously envisaged. These findings were recently published in EPJ B by Yunyun Li Tongji University, Shanghai, China, and colleagues in Singapore.
Heat conduction depends on the internal energy transferred by microscopic diffusion and collisions of particles, such as electrons, within a given body. Anomalous heat conduction can be best studied in a particular kind of model: one that accounts for the thermal transport in a one-dimensional (1D) lattice. In this study, the chosen 1D model is dubbed the coupled rotator lattice model.
The specificities of the chosen model is that it conserves heat conductions - that is heat transport and heat diffusion - as well as momentum diffusion. Under these conditions, the expectation is that the heat conduction would be anomalous. But in reality, numerical simulations have previously demonstrated that the model exhibits normal heat conduction. For physicists, these results don't intuitively match the fact the heat is diffusing in a way that preserves its momentum. To complement their approach, they also drew a comparison with a single kicked rotator.
The authors systematically investigated how heat conductivity changes with temperature in the selected 1D model. This approach led them to the thesis that heat conductivity correlates with a power law, instead of an exponential scaling as previously predicted. Further, this phenomenon occurs without a transition temperature above which the heat conduction is normal and below which it is anomalous.
INFORMATION:
Reference:
Y. Li, N. Li and B. Li (2015), Temperature dependence of thermal conductivities of coupled rotator lattice and the momentum diffusion in standard map, Eur. Phys. J. B, DOI 10.1140/epjb/e2015-60361-5
ELSE PRESS RELEASES FROM THIS DATE:
2015-07-14
Kyoto, Japan - A group led by Assistant Professor Dan Ohtan Wang from Kyoto University's Institute for Integrated Cell-Material Sciences (iCeMS) in Japan successfully visualized RNA behavior and its response to drugs within the living tissue brain of live mice by labeling specific RNA molecules with fluorescent probes. Their study, published in Nucleic Acids Research, can potentially lead to faster, and more accurate screening processes for the discovery and development of new drugs.
RNA is a molecule that plays a key role within a living organism, holding information ...
2015-07-14
BOSTON (July 13) - A study published today in the Journal of the American Medical Association shows that genetic test results, as revealed by non-invasive prenatal testing for fetal chromosome abnormalities, may detect underlying conditions in the mother, including cancer. The study reports on a case series of eight women who had abnormal noninvasive prenatal testing results. Their fetuses had normal chromosomes; retrospective genomic analysis showed the results were due to undiagnosed cancers in the mothers.
A team of scientists and clinicians, led by Diana W. Bianchi, ...
2015-07-14
AURORA, Colo. (July 14, 2015) - A new study by a team of researchers at the University of Colorado School of Medicine on the Anschutz Medical Campus found that long-term stimulant abuse had more significant effects on brain volume in women compared with men.
For the study, Jody Tanabe, MD, professor of radiology, and her colleagues sought to determine how the brains of people previously dependent on stimulants were different from the brains of healthy people. The results were published online in the journal Radiology.
"We specifically wanted to determine how these brain ...
2015-07-14
CHICAGO--Consumers who get fiber from many sources--both naturally occurring and added in manufacturing--may benefit more than people who limit their intake to a single type, according to a July 12th symposium at IFT15: Where Science Feeds Innovation hosted by the Institute of Food Technologists (IFT) in Chicago.
Researchers have found that Americans fall woefully short of the recommended amount of dietary fiber per day--38 grams for men and 25 grams for women. Men typically get around 18 grams and women get around 15 grams, said Julie Miller Jones, Ph.D, LN, CNS, professor ...
2015-07-14
The CORRECT study, published ahead of print online today in The Lancet Oncology, is one of the largest trials to date comparing data provided by liquid versus tissue biopsy in metastatic colorectal cancer patients.
According to the study, liquid biopsy (BEAMing technology) could become an essential tool for analyzing tumor genotypes in real time, and identifying significant mutations that occur during the course of disease and are not detected by tissue biopsy.
The results of the phase III study, co-directed by Josep Tabernero, Head of the Vall d'Hebron University ...
2015-07-14
Funeral directors, who prepare bodies for burial, may be at heightened risk of the neurodegenerative disease amyotrophic lateral sclerosis, or ALS for short, as a result of the formaldehyde used in embalming fluid, suggests research published online in the Journal of Neurology Neurosurgery & Psychiatry.
ALS, also known as Lou Gehrig's disease, was the subject of last year's ice bucket challenge. It is progressive, causing muscle weakness, paralysis, and eventually respiratory failure and death. There is no cure for the condition, which is thought to affect 450,000 people ...
2015-07-14
One in four dogs competing in the world's largest canine show (Crufts) is overweight, despite the perception that entrants are supposed to represent ideal specimens of their breed, reveals research published online in Veterinary Record.
The widespread dissemination of show dog images online may be 'normalising' obesity in dogs, now recognised to be a common canine disorder, say the researchers.
As in people, obesity in dogs has been linked to orthopaedic problems, diabetes, respiratory disease, and certain types of cancer. It also affects both the quality and length ...
2015-07-14
One in four dogs competing at Crufts is overweight, researchers at the University of Liverpool have found.
The competition is the largest show of its kind in the world, showcasing the best physical and behavioural qualities in a variety of canine breeds. Research, published in the Veterinary Record, however, reveals that up to 26% of some of the best show dogs, such as pugs, Basset hounds, and Labrador retrievers, are actually overweight.
The team studied more than a 1,000 images of 28 dog breeds that had been placed between first and fifth in their class during ...
2015-07-14
1. Community Preventive Services Task Force recommends diet and exercise interventions to prevent diabetes
Evidence shows combined diet and exercise promotion programs are effective and cost-effective for preventing type 2 diabetes in at-risk patients
Free content
Clinical guideline: http://www.annals.org/article.aspx?doi=10.7326/M15-1029
Evidence review: http://www.annals.org/article.aspx?doi=10.7326/M15-0452
Economic evidence review: http://www.annals.org/article.aspx?doi=10.7326/M15-0469
Editorial: http://www.annals.org/article.aspx?doi=10.7326/M15-1563
URLs ...
2015-07-14
PHILADELPHIA -Patients over 50 with ulcerative colitis (UC), a chronic disease of the colon, who undergo surgery to treat their condition live longer than those who are treated with medications, according to a new study from the Perelman School of Medicine at the University of Pennsylvania. The results are published this week in Annals of Internal Medicine.
"Ulcerative colitis is a chronic disease that most physicians opt to treat with medications, as opposed to surgery," said the study's lead author Meenakshi Bewtra, MD, PhD, MPH, assistant professor of Medicine and ...
LAST 30 PRESS RELEASES:
[Press-News.org] Law governing anomalous heat conduction revealed
Study finds the law governing how heat transport scales up with temperature
