(Press-News.org) Accurately sensing rotation is important to a variety of technologies, from today's smartphones to navigational instruments that help keep submarines, planes, and satellites on course. In a paper accepted for publication in the American Institute of Physics' journal Review of Scientific Instruments, researchers from the Technical University of Munich and New Zealand's University of Canterbury discuss what are called "large ring laser gyroscopes" that are six orders of magnitude more sensitive than gyroscopes commercially available. In part, the increased sensitivity comes from the scaled-up size – the largest of these gyroscopes encloses an area of 834 square meters – meaning these instruments are no longer compatible with navigation applications. In addition, a very involved series of corrections must be made when using these instruments to account for a variety of factors, including the gravitational attraction of the moon. According to the researchers, however, the progress in these devices has made possible entirely new applications in geodesy, geophysics, seismology, and testing theories in fundamental physics such as the effects of general relativity.
Ring laser gyroscopes rely on laser beams propagating in opposite directions along the same closed loop or "ring." The beams interfere with one another forming a stable pattern, but that pattern shifts in direct proportion to the rotation rate of the whole laser-ring system (called the "Sagnac effect"). Large ring laser gyroscopes are attached to the Earth's crust so that a shift in that pattern (seen as an observed beat note in an actively lasing device) is directly proportional to the rotation rate of the Earth. Perturbations in that rotation rate capture the momentum exchange between the atmosphere, hydrosphere, and lithosphere, and so large ring laser gyroscopes could be used to indirectly monitor the combined effects of variations in global air and water currents, for example. They may also be used both to supplement and improve calculations currently made with Very Long Baseline Interferometry (VLBI) techniques for measuring the orientation of the instantaneous rotation axis of the Earth and the length of day. Additionally, changes in the ring's orientation also shifts the beat note of the interferometer, making the large ring laser gyroscope useful for detecting tilts in the Earth's crust, which current seismometers cannot distinguish from horizontal acceleration.
###
Article: "Large Ring Lasers for Rotation Sensing" is accepted for publication in the journal Review of Scientific Instruments.
Link: http://rsi.aip.org/resource/1/rsinak/v84/i4/p041101_s1
Authors: Karl Ulrich Schreiber (1, 2), Jon-Paul R. Wells (2)
(1) Technical University of Munich
(2) University of Canterbury
Scaling up gyroscopes: From navigation to measuring the Earth's rotation
2013-05-06
ELSE PRESS RELEASES FROM THIS DATE:
Research finds new cause for common lung problem
2013-05-06
New research has found that in cases of lung edema, or fluid in the lungs, not only do the lungs fail to keep water out as previously believed, but they are also allowing water to pump in.
"Usually, our lungs pump fluid out of the air space, and it was previously believed that this pump mechanism just stopped when people had lung edema," said Dr. Wolfgang Kuebler, a scientist at St. Michael's Hospital. "But we've found not only do they stop pumping fluid out as they're supposed to do, they've gotten confused and are actually pumping in the reverse direction, bringing ...
Hospital surgical volume should be considered when judging value of procedures
2013-05-06
SAN DIEGO – The volume of cases performed at an institution each year has a direct effect on the outcome of surgical procedures, and should always be considered when looking at the benefits of a technique, according to a team of researchers at Henry Ford Hospital in Detroit.
Those conclusions will be presented May 5 at the annual meeting of the American Urological Association in San Diego.
The starting point of the study was the rapid increase in the use of surgical robots to assist in radical prostatectomy, in which the entire prostate gland and some surrounding tissue ...
Genome sequencing provides unprecedented insight into causes of pneumococcal disease
2013-05-06
Boston, MA — A new study led by researchers from Harvard School of Public Health (HSPH) and the Wellcome Trust Sanger Institute in the UK has, for the first time, used genome sequencing technology to track the changes in a bacterial population following the introduction of a vaccine. The study follows how the population of pneumococcal bacteria changed following the introduction of the 'Prevnar' conjugate polysaccharide vaccine, which substantially reduced rates of pneumococcal disease across the U.S. The work demonstrates that the technology could be used in the future ...
Media advisory: Brain cell injections may quiet epileptic seizures
2013-05-06
More than two million people in the United States suffer from epilepsies, a group of neurological disorders caused by abnormal nerve cell firing in the brain which often produce debilitating seizures. Although anti-epileptic drugs and other therapies reduce seizures in about two-thirds of patients, the remaining one-third do not respond to any form of therapy and those who take drugs can experience harmful side effects. NIH funded researchers at the University of California at San Francisco used a mouse model of epilepsy to show that transplanting new born inhibitory nerve ...
Divide and define: Clues to understanding how stem cells produce different kinds of cells
2013-05-06
ANN ARBOR—The human body contains trillions of cells, all derived from a single cell, or zygote, made by the fusion of an egg and a sperm. That single cell contains all the genetic information needed to develop into a human, and passes identical copies of that information to each new cell as it divides into the many diverse types of cells that make up a complex organism like a human being.
If each cell is genetically identical, however, how does it grow to be a skin, blood, nerve, bone or other type of cell? How do stem cells read the same genetic code but divide into ...
Scientists alarmed by rapid spread of Brown Streak Disease in cassava
2013-05-06
BELLAGIO, ITALY (6 MAY 2013)— Cassava experts are reporting new outbreaks and the increased spread of Cassava Brown Streak Disease or CBSD, warning that the rapidly proliferating plant virus could cause a 50 percent drop in production of a crop that provides a significant source of food and income for 300 million Africans.
The "pandemic" of CBSD now underway is particularly worrisome because agriculture experts have been looking to the otherwise resilient cassava plant—which is also used to produce starch, flour, biofuel and even beer—as the perfect crop for helping to ...
A new cost-effective genome assembly process
2013-05-06
The U.S. Department of Energy Joint Genome Institute (DOE JGI) is among the world leaders in sequencing the genomes of microbes, focusing on their potential applications in the fields of bioenergy and environment. As a national user facility, the DOE JGI is also focused on developing tools that more cost-effectively enable the assembly and analysis of the sequence that it, as well as other genome centers, generates.
Despite tremendous advances in cost reduction and throughput of DNA sequencing, significant challenges remain in the process of efficiently reconstructing ...
As climate changes, boreal forests to shift north and relinquish more carbon than expected
2013-05-06
It's difficult to imagine how a degree or two of warming will affect a location. Will it rain less? What will happen to the area's vegetation?
New Berkeley Lab research offers a way to envision a warmer future. It maps how Earth's myriad climates—and the ecosystems that depend on them—will move from one area to another as global temperatures rise.
The approach foresees big changes for one of the planet's great carbon sponges. Boreal forests will likely shift north at a steady clip this century. Along the way, the vegetation will relinquish more trapped carbon than most ...
More hurricanes for Hawaii?
2013-05-06
News of a hurricane threat sends our hearts racing, glues us to the Internet for updates, and makes us rush to the store to stock up on staples. Hawaii, fortunately, has been largely free from these violent storms in the recent past, only two having made landfall in more than 30 years.
Now a study headed by a team of scientists at the International Pacific Research Center, University of Hawaii at Manoa, shows that Hawaii could see a two-to-three-fold increase in tropical cyclones by the last quarter of this century. The study, which appears in the May 5, 2013, online ...
NIH study provides clarity on supplements for protection against blinding eye disease
2013-05-06
Adding omega-3 fatty acids did not improve a combination of nutritional supplements commonly recommended for treating age-related macular degeneration (AMD), a major cause of vision loss among older Americans, according to a study from the National Institutes of Health (NIH). The plant-derived antioxidants lutein and zeaxanthin also had no overall effect on AMD when added to the combination; however, they were safer than the related antioxidant beta-carotene, according to the study published online today in the Journal of the American Medical Association.
"Millions of ...