Updated README

I updated all the documentation, but forgot about the README, which is possibly the first place anyone looks.

README.md

@@ -24,40 +24,33 @@ pkg> add GasDispersion
 
 ## Example usage
 
-This scenario is adapted from CCPS *Guidelines for Consequence Analysis of
-Chemical Releases*, CCPS, pg 47.
-
-Suppose we wish to model the dispersion of gaseous propane from a leak from a storage 
-tank, where the leak is from a 10 mm hole that is 3.5 m above the ground and the 
-propane is at 25°C and 4barg. Assume the discharge coefficient $c_{D} = 0.85$
-
-For ambient conditions we assume the atmosphere is dry air at standard conditions
-of 1atm and 25°C, with a windspeed of 1.5m/s and class F stability (a "worst case"
-atmospheric stability)
+Suppose we wish to model the dispersion of gaseous propane from a leak from a storage tank, where the leak is from a 10mm hole that is 3.5m above the ground and the propane is at 25°C and 4barg. Assume the discharge coefficient $c_{D} = 0.85$. This scenario is adapted from CCPS *Guidelines for Consequence Analysis of Chemical Releases*
 
+First we define the scenario
 
 ```julia
 using GasDispersion
 
-propane = Substance(name = :propane,
-                    gas_density = 9.7505, # kg/m^3, NIST Webbook
-                    liquid_density = 526.13, # kg/m^3, NIST Webbook
-                    reference_temp= 298.15, # K
-                    reference_pressure= 501325, # Pa
-                    boiling_temp = 231.04, # K, NIST Webbook
-                    latent_heat = 425740.0, # J/kg, 
-                    gas_heat_capacity = 1678.0, # J/kg/K, 
-                    liquid_heat_capacity = 2520.0) # J/kg/K, 
-
-scn = scenario_builder(propane, JetSource;
+propane = Substance(name="propane",
+              molar_weight=0.044096,     # kg/mol
+              liquid_density=526.13,     # kg/m³
+              k=1.142,
+              boiling_temp=231.02,       # K
+              latent_heat=425740,        # J/kg
+              gas_heat_capacity=1678,    # J/kg/K
+              liquid_heat_capacity=2520) # J/kg/K
+
+Patm = 101325 # Pa
+P1 = 4e5 + Patm # Pa
+T1 = 25 + 273.15 # K
+
+scn = scenario_builder(propane, JetSource; 
        phase = :gas,
-       diameter = 0.01, # m
+       diameter = 0.01,  # m
        dischargecoef = 0.85,
-       k = 1.15,         # heat capacity ratio, from Crane's
        temperature = T1, # K
        pressure = P1,    # Pa
-       height = 3.5,     # m, height of hole above the ground
-       duration = 1)     # s, duration of release
+       height = 3.5)     # m, height of hole above the ground
 ```
 
 This generates a `Scenario` defined for a gas jet discharging into dry air
@@ -66,18 +59,18 @@ concentration at any point downwind of the release point, assuming the release
 is a continuous plume, using
 
 ```julia
-# returns a callable
-pl = plume(scn, GaussianPlume)
-
-pl(x,y,z) # gives the concentration in vol fraction at the point x, y, z
+p = plume(scn, GaussianPlume)
 ```
-where the coordinate system is such that the release point is at x=0, y=0, z=h
 
-Similarly we could model an instantaneous release, assuming all of the mass was
-released during 1 second, using a "puff" model
+Where `p` is a callable which returns the concentration (in vol fraction) at any point. For example at 100m downwind and at a height of 2m
+
 ```julia
-# returns a function
-pf = puff(scn, GaussianPuff)
+p(100,0,2)
+
+# output
+
+0.0002006455298894473
 
-p(x,y,z,t) # gives the concentration in vol fraction at the point x, y, z and time t
 ```
+
+See [the documentation](https://aefarrell.github.io/GasDispersion.jl/dev/) for details on the additional plume and puff models and worked examples.