public static double CalculateEND(DepthFactor depthF, BreathGas gas)
{
var air = new BreathGas();
var ppN = DivingMath.SeaLevelPreasureBars * BreathGas.GetGasPartialPreasureForDepth(depthF, gas.PpN);
var depth = DivingMath.PreasureBarsToDepth(ppN / air.PpN, depthF.WaterDensity);
return(Math.Round(depth.Depth, 1));
}
public const double WaterVapourPreasureBars = 0.023; // for t 20C
public static double DepthToPreasureBars(DepthFactor depthFactor)
{
if (depthFactor.Depth <= 0)
{
return(SeaLevelPreasureBars);
}
if (depthFactor.WaterDensity == default(double))
{
depthFactor.WaterDensity = FreshWaterDensity;
}
var weightDensity = depthFactor.WaterDensity * GravityG;
return(SeaLevelPreasureBars + depthFactor.Depth * weightDensity / PascalsPerBar);
}
private void CalculateCompartmentPresures(double time, double depth, BreathGas gas, CompartmentCalculations[] tissues = null)
{
var depthFact = new DepthFactor(depth, _waterDensity);
double ppNitro = gas.PpN * (BreathGas.GetGasPartialPreasureForDepth(depthFact, 1.0) - DivingMath.WaterVapourPreasureBars);
double ppHe = gas.PpHe * (BreathGas.GetGasPartialPreasureForDepth(depthFact, 1.0) - DivingMath.WaterVapourPreasureBars);
int index = 0;
foreach (var cpt in _compartments)
{
var data = (tissues ?? _compartmentData)[index];
var n2Koef = 1.0 - Math.Pow(2.0, -time / cpt.N2HalfTime);
var heKoef = 1.0 - Math.Pow(2.0, -time / cpt.HeHalfTime);
data.N2Presure = data.N2Presure + ((ppNitro - data.N2Presure) * n2Koef);
data.HePresure = data.HePresure + ((ppHe - data.HePresure) * heKoef);
++index;
}
}
private BreathGas SelectDecoGas(DepthFactor currDepth, double decoStopDepth)
{
const double MaxDecoPpO = 1.6;
const double OptimalDecoPpO = 1.5;
if ((_diveParameters.DecoLevels?.Count() ?? 0) == 0)
{
return(_diveParameters.Levels.Last().Gas);
}
var decoPpO = MaxDecoPpO;
if ((currDepth.Depth - decoStopDepth) > (DecoStopsStep + double.Epsilon))
{
decoPpO = OptimalDecoPpO;
}
var gasesCanUse = new List <KeyValuePair <double, BreathGas> >(_diveParameters.DecoLevels.Count());
// explicit depth gases go first
var explicitDepthGases = _diveParameters.DecoLevels.Where(d => d.Depth > double.Epsilon);
if (explicitDepthGases.Any())
{
var suitedDecoGases = explicitDepthGases.Where(d => currDepth.Depth <= d.Depth);
if (!suitedDecoGases.Any())
{
return(_diveParameters.Levels.Last().Gas);
}
var minDepth = explicitDepthGases.Where(d => currDepth.Depth <= d.Depth).Min(d => d.Depth);
var explicitDecoGas = explicitDepthGases.FirstOrDefault(d => DivingMath.CompareDouble(d.Depth, minDepth));
if (explicitDecoGas != null)
{
return(explicitDecoGas.Gas);
}
else
{
return(_diveParameters.Levels.Last().Gas);
}
}
else
{
foreach (var decoLevel in _diveParameters.DecoLevels)
{
var currDecoPpO = BreathGas.GetGasPartialPreasureForDepth(currDepth, decoLevel.Gas.PpO);
if (currDecoPpO <= decoPpO)
{
gasesCanUse.Add(new KeyValuePair <double, BreathGas>(currDecoPpO, decoLevel.Gas));
}
}
if (gasesCanUse.Count == 0)
{
return(_diveParameters.Levels.Last().Gas);
}
return(gasesCanUse.First(g => DivingMath.CompareDouble(g.Key, gasesCanUse.Max(k => k.Key))).Value);
}
}
