Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ascending safely from the depth

06.11.2006
Ascending from great depths can be a risky process. A personally adjusted dive computer increases safety.

Decompression sickness occurs in connection with rapid ascent from deep sea – from high pressure to low pressure – and is caused by formation of gas in the human body. Just as soft drinks contain carbonic acid, blood contains physically dissolved gases. These gases may form bubbles when the pressure drops. Ascending from deep sea is like opening the screw cap of a bottle of carbonated water: The pressure decreases, and bubbles are released.

The more the pressure drops, the larger the bubbles become. The bubbles can develop in different tissues in the body, or in the bloodstream. If a large gas bubble develops in a blood vessel, the bubble may function as a blood clot.

Researchers at NTNU have discovered more of how these bubbles behave and change as divers ascend to the surface. This knowledge will influence the emergency procedures for professional divers and submarine personnel – and may also be used to develop an individually adjusted dive computer.

PIGS SHOW THE WAY - “In theory, the best ascending profile is to rise slowly and gradually, from all depths. But this is not feasible in practice,” says research fellow Andreas Møllerløkken. “The water movements make it too difficult.”

That is why deep or prolonged dives require the divers to make safety stops on their way to the surface to prevent the pressure drop of becoming a shock to the organism. This is normal procedure today.

Møllerløkken and his fellow researcher Christian Gutvik discovered that divers should not only make ordinary safety stops, but actually go a bit further down towards the depth afterwards. In this instance, the ‘divers’ were pigs in pressure chambers. Thanks to these pigs, the researchers were able to map how gas bubbles are formed and change under different conditions.

“We know now what happens with gases in the blood when the pressure changes. And we have seen that this can be influenced by medication,” Møllerløkken explains.

TAILORMADE COMPUTER - The two researchers at the Department of Circulation and Imaging at NTNU are currently developing the inside of a new dive computer. It ’monitors’ the diver in a totally new way and makes him more secure in deep water because it is based on his own physical condition.

A dive computer is usually attached to the wrist and has a depth sensor and a watch. It is programmed to inform the diver of how much time he has left before he must begin ascending to the surface. It also indicates whether safety stops are necessary. However, it is based on theoretical tables of how gases behave in different types of tissues. It makes no consideration to individual factors which strongly influence how gases are absorbed by the blood and the formation of bubbles: the diver's height, weight, body fat percentage, maximum and minimum pulse rates, oxygen uptake, and gender.

The diver feeds the new computer with his personal data. This information, combined with continuous measuring of the pulse, enables the computer to calculate how the body is affected by the dive and tell at any time how the ascent to the surface should be performed.

Measuring the pulse is essential. The heart rate indicates the blood flow in the body, which determines the uptake of gases. For instance, if a person dives with a pulse rate close to maximum pulse over a certain period of time, the gas uptake in the body will be totally different from that of relaxing leisure dives.

The Swiss producer Uwatec wishes to put the new dive computer into production. The features were tested in the Red Sea in January, but some quality assurance remains before the computer is released on the market – probably in 2008.

PINCHING MARGINS - To amateur divers, the time they spends rising to the surface, is wasted. To professional divers, it also represents a loss of money. But if the ascent is to take place without risk, it must not happen too quickly. For this reason, existing safety routines for divers include large safety margins.

The routines are, however, not based on how gas actually behaves in a diver’s body. Research fellows Møllerløkken and Gutvik wish to incorporate the knowledge of bubbles into the safety routines.

“In practice, a bubble-based ascent profile may allow a faster ascent, since it better describes reality. There will no longer be a need for unnecessarily conservative safety margins,” concludes Andreas Møllerløkken.

By Hege J. Tunstad

Nina Tveter | alfa
Further information:
http://www.ntnu.no

More articles from Information Technology:

nachricht World's thinnest hologram paves path to new 3-D world
18.05.2017 | RMIT University

nachricht Internet of things made simple: One sensor package does work of many
11.05.2017 | Carnegie Mellon University

All articles from Information Technology >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

Im Focus: Bacteria harness the lotus effect to protect themselves

Biofilms: Researchers find the causes of water-repelling properties

Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...

Im Focus: Hydrogen Bonds Directly Detected for the First Time

For the first time, scientists have succeeded in studying the strength of hydrogen bonds in a single molecule using an atomic force microscope. Researchers from the University of Basel’s Swiss Nanoscience Institute network have reported the results in the journal Science Advances.

Hydrogen is the most common element in the universe and is an integral part of almost all organic compounds. Molecules and sections of macromolecules are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

Innovation 4.0: Shaping a humane fourth industrial revolution

17.05.2017 | Event News

Media accreditation opens for historic year at European Health Forum Gastein

16.05.2017 | Event News

 
Latest News

New approach to revolutionize the production of molecular hydrogen

22.05.2017 | Materials Sciences

Scientists enlist engineered protein to battle the MERS virus

22.05.2017 | Life Sciences

Experts explain origins of topographic relief on Earth, Mars and Titan

22.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>