NRCS Travel Time Calculator NRCS Travel Time Calculator Estimate the time of concentration (travel time) using the NRCS/Kirpich equation: \[ T_c = 0.0078 \frac{L^{0.77}}{S^{0.385}} \] * Enter the watercourse length \( L \) (ft) and the slope \( S \) (ft/ft). Step 1: Enter Parameters Length \( L \) (ft): Example: 1000 ft Slope \( […]
Read MoreWeighted Curve Number Calculator for a Basin Weighted Curve Number Calculator for a Basin Calculate the overall curve number of a basin by weighing the curve numbers of subbasins by their areas: \[ CN_{weighted} = \frac{\sum (CN_i \times \text{Area}_i)}{\sum \text{Area}_i} \] * Enter the area (in consistent units) and curve number for each subbasin. Step […]
Read MoreWeighted Curve Number Calculator for a Basin Weighted Curve Number Calculator for a Basin Calculate the overall curve number of a basin by weighing the curve numbers of subbasins by their areas: \[ CN_{weighted} = \frac{\sum (CN_i \times \text{Area}_i)}{\sum \text{Area}_i} \] * Enter the area (in consistent units) and curve number for each subbasin. Step […]
Read MoreComposite Curve Number Calculator with Unconnected Impervious Area Composite Curve Number Calculator with Unconnected Impervious Area Calculate the composite curve number for a watershed that has an unconnected impervious area using: \[ CN_{comp} = f_{UIA} \times CN_{UIA} + \left(1 – f_{UIA}\right) \times CN_{perv} \] * Enter the percentage of unconnected impervious area, the curve number […]
Read MoreComposite Curve Number Calculator with Connected Impervious Area Composite Curve Number Calculator Calculate the composite curve number for a watershed with a connected impervious area using: \[ CN_{comp} = f_{CIA} \times 98 + (1 – f_{CIA}) \times CN_{perv} \] * Enter the percentage of connected impervious area (CIA%) and the curve number for the pervious […]
Read MoreKelvin Equation Vapor Pressure Change Calculator Kelvin Equation Vapor Pressure Calculator Calculate the vapor pressure over a curved surface using the Kelvin Equation: \[ \ln\left(\frac{p}{p_0}\right) = \frac{2\gamma V_m}{R\,T\,r} \] * Enter the flat surface vapor pressure \( p_0 \) (Pa), surface tension \( \gamma \) (N/m), molar volume \( V_m \) (m³/mol), radius \( r […]
Read MoreFourier Number Calculator Fourier Number Calculator Calculate the Fourier number using the formula: \[ Fo = \frac{\alpha\, t}{L^2} \] * Enter thermal diffusivity \( \alpha \) (m²/s), time \( t \) (s), and characteristic length \( L \) (m). Step 1: Enter Parameters Thermal Diffusivity, \( \alpha \) (m²/s): Example: 1.2e-5 m²/s Time, \( t […]
Read Morevan der Waals Coefficients Calculator Calculate the van der Waals constants \( a \) and \( b \) using the critical properties of a substance. \[ a = \frac{27 R^2 T_c^2}{64 P_c} \quad \text{and} \quad b = \frac{R T_c}{8 P_c} \] * Enter the critical temperature (K) and critical pressure (atm). Step 1: Enter Critical […]
Read MoreAmount of Substance (n) Calculator Amount of Substance (n) Calculator Calculate the number of moles using the formula: \[ n = \frac{m}{M} \] where \( m \) is the mass in grams and \( M \) is the molar mass in g/mol. * Enter the mass of the substance (g) and its molar mass (g/mol). […]
Read MoreBasic Stoichiometry Calculator Basic Stoichiometry Calculator Convert the mass of a reactant to the mass of a product using stoichiometric relationships. For a reaction: \( a\,\text{A} \rightarrow b\,\text{B} \) * Enter the mass and molar mass of reactant A, its stoichiometric coefficient, and the molar mass and coefficient for product B. Step 1: Enter Reaction […]
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