scuba, a package in R
that performs theoretical calculations
about scuba diving --- dive profiles,
decompression models, gas toxicity and so on.dive. For example, the command
d <- dive(c(18, 45)) specifies a dive to 18 metres
for 45 minutes. The command d <- dive(c(18, 45), c(5,3))
specifies a dive to 18 metres for 45 minutes followed by a safety stop
at 5 metres for 3 minutes. Multilevel dives with any number of stages
are specified in the same way. The resulting object d is an object of class "dive".
It can be plotted as a conventional dive profile by typing
plot(d) as explained in the help entry for
plot.dive.
It can be printed as a table of depths and times
by typing its name d, or by typing
print(d,seconds=FALSE) to print times to the nearest minute,
as explained in the help entry for print.dive.
A summary of the dive (with such information as the average depth,
maximum depth and the main stages of the dive) can be printed
by typing summary(d).
By default, the function dive fills in some details
about the dive. It assumes that the diver breathes compressed air;
the dive starts and ends at the surface
(depth zero); the diver descends
at the default descent rate of 30 metres per minute; and the diver
ascends at the default ascent rate of 18 metres per minute.
These defaults can be changed, as explained below.
haldane. If d is a dive object
then haldane(d) returns a vector containing the nitrogen
tissue tensions (ata) at the end of the dive,
in each of the 8 tissue compartments
of the DSAT model. You can choose other compartment models;
for example to use the classical US Navy model,
type haldane(d, Halftimes[["USN"]]). For other
alternative compartment models,
see Halftimes, Workman65
or BuehlmannL16A. To inspect the tissue tensions during the dive,
use the interactive function showstates.
This plots the dive and waits for you to click on
a position in the graph. The tissue tensions at that
instant are displayed as a bar plot.
Bubble theory calculations are not yet implemented.
The total oxygen toxicity incurred during a dive can be computed
by oxtox.
"gas".
The object air is a representation of compressed air
(21% oxygen, 79% nitrogen) as an object of this class.
(Don't reassign another value to this object!!!)
Nitrox mixtures (mixtures of oxygen and nitrogen) can be
represented using the function nitrox.
For example, EAN 32 is represented by nitrox(0.32). There are methods for print and summary
for gas objects.
Standard nitrox calculations are also available, for example
ead equivalent air depth
mod maximum operating depth
maxmix richest nitrox mix for a given depth
}
"dive" object contains information
about the breathing gas used. The breathing gas is determined
when the dive object is created, and cannot be changed later.
Information about the breathing gas is passed to
the function dive when it creates the dive object.
The function dive interprets its arguments
as a sequence of actions or events occurring during the dive.
If an argument is a vector of length 2, it is interpreted
as c(depth,time) specifying the depth and duration
of a stage of the dive. If the argument is a single number,
it is interpreted as a depth, meaning that the diver ascends or
descends to this depth. Each argument to dive may also be a "gas" object,
like nitrox(0.32),
which means that the diver switches to this gas.
So, for example,
dive(nitrox(0.32), c(30,20))
means a dive to 30 metres for 20 minutes conducted on EAN 32
(Nitrox 0.32) from start to finish.
The command
dive(c(30,20), 5, nitrox(0.36), c(5,3)) means
a dive on air to 30 metres for 20 minutes, ascending to 5 metres
while breathing air, then switching to EAN 36 for a safety stop
at 5 metres for 3 minutes.
The total oxygen toxicity incurred by a diver on
any Nitrox dive can be calculated using oxtox.
scuba is a package for performing
calculations in the theory of scuba diving.
The package supports
scuba package is intended only
for use in research and education about the mathematical
and statistical basis of decompression theory. It is
not designed for actual use in scuba diving and related activities.
See the disclaimer in scuba.disclaimer.