Decompression Algorithm
We are discussing decompression theories and sharing idea here.
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116
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15
Decompression Algorithm
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We are discussing decompression theories and sharing idea here.
Members
116
Posts
15
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Bühlmann
RGBM
VPM
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    Part 1... More
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    Bubbles transfers between tissues based on diffusion model. This is similar to that heat transfers from hot spot to cold one. Bubbles moves from tissues suffered in higher pressure to those with lower pressure. Transferring rates depend on the medium and that is why tissues have different lifetime of absorbing or releasing pressure. Therefore, bubbles are moving and growing depending on pressure of tissues. To have the knowledge of size of bubbles, we have to obtain the diffusion rate and to calculate the expansion according to the pressure. https://en.m.wikipedia.org/wiki/Thermal_diffusivity... More
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    According to Haldane's decompression model, compartments which is known as artificial tissues have different half time approaching to achieve ambient pressure. Half time is a period which the difference between pressure inside and outside tissues is reduced to be half of original one. After two periods later, the difference remains 25% of origin. Since the transferring speed depends on the ratio of the gradient of pressure, the speed varies fast at the beginning and then approaches to the ambient pressure asymptotically. In other words, when we dives deeper, the gradient comparing with M0 which is the M value at sea level is larger. Then, the pressure inside tissue growth rapidly and will be larger than M0 sooner than the situation staying around the shallow depth when the gradient is smaller. That is the reason the no decompression limit drops rapidly around the deep depth.... More
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    Here are tables of M-values. Simply, M-values are the upper bound of pressure inside tissues and corresponds to the risk of obtaining decompression sickness. These are the empirical data from researches and provides us references to calculate the no decompression limit when the pressure is lower than M-values. Furthermore, people applies safety factors to reduce the risk and 100% of safety factor is the difference between M-values and ambient pressure. Usually, it is not recommended to set safety factor larger than 100% which corresponds to the settings over the limit of M-values to increase the risk to obtain decompression sickness. http://www.ddplan.com/reference/mvalues.pdf... More
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    Ideal gas model tells us the pressure is proportional to the temperature and is inversely proportional to the volume. Therefore, surface air consumption is the metric to measure the rate of gases exhausted because the pressure and the temperature in the tank varies during a dive and the rate should be normalized to the one at 1 atm as the reference. Now, we just need to care of the consumption rate in pressure or in volume only per minute and then the time of a trip can be planned to avoid the interruption because gases are exhausted.... More
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    There is the phenomenon called supersaturation. Gases are usually dissolved into the solvent like blood with the certain concentration with respect to the pressure and the temperature. However, it is possible the concentration is higher than the limit. For example, carbon dioxide is dissolved in Coca Cola with the rather high pressure or temperature. After suddenly dropping the pressure or cooling the temperature, the solution becomes supersaturated until the solute precipitates to the saturation point. Then, we are able to find bubbles after shaking Coca Cola to break the meta-stable state.... More
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    Part 2... More
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    Waiting for Part III... More

    All of them are based on diffusion model and phase transition of thermal dynamics. Probably, we are able to display some simple models before combining them together . http://tecvault.t101.ro/ModernDecompression_Wienke.pdf... More
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    It is interesting people are searching the shortest decompression path in time. Gas embolism is an embolism caused by one or more bubbles of gas in the circulatory system, and this article assumes there is the close relation between venous embolism and risk of decompression sickness. Bubble model is used to conduct the numeric experiment and the shortest path depends on the size of bubbles per minute. Probably, we are also able to discuss the result include the effect of fast and slow tissues and comparing results from different decompression models. http://folk.ntnu.no/torarnj/CDC09_draft_revision5.pdf... More
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