Static Saturated Salt Equilibrium Desiccators
Maintains constant chemical water vapor activities (RH 11% to 85%) inside sealed glass jars.
Agricultural Engineering / Equilibrium Moisture Isotherms
FREE TO EXPLORELABORATORY 21 · AGRICULTURAL ENGINEERING
Equilibrium Moisture Content (EMC) & Sorption Isotherms (Modified Henderson Model)
Determine the equilibrium moisture content (EMC) of agricultural cereal grain at constant temperature across variable relative humidities and calibrate the Modified Henderson sorption isotherm model. Explore interactive farm machinery simulation, irrigation hydraulics, and agricultural engineering telemetry.
FARM MACHINERY · SOIL & WATER · POST-HARVEST · STRUCTURES
Your virtual agricultural engineering laboratory.
LOGARITHM OF EQUILIBRIUM MOISTURE LN(M_E)—
FIELD & TEST CELL TELEMETRY
Ready to sample with ln(-ln(1-RH)) = -0.63 transformed.
Adjust ln(-ln(1-RH)), then execute agricultural trial.
Agricultural engineering telemetry and biosystems states are evaluated rigorously using 64-bit IEEE 754 precision. Residuals reflect ordinary least-squares regression across successive observations. Continuous data structures support high-fidelity agricultural and environmental modeling.
Agricultural assumptions and boundary condition limits
Static gravimetric equilibration requires 2 to 4 weeks per trial, during which mold can develop at high humidities (RH > 80%). Evaluated using shelled yellow dent corn at constant 25°C in static gravimetric chambers containing analytical saturated salt solutions (LiCl, MgCl₂, Mg(NO₃)₂, NaCl, KCl).
Agricultural apparatus & field instrumentation sensors.
Temperature-Controlled Environmental Incubator (25.0°C)
Maintains isothermal test conditions within ±0.2°C over multi-week equilibration.
Perforated Stainless Steel Sample Baskets
Suspends thin layers of grain kernels directly above the saturated salt solutions.
High-Precision Analytical Balance (0.0001 g)
Logs grain sample mass changes every 48 hours until true asymptotic equilibrium is verified.
Forced-Air Drying Oven (103°C)
Determines final bone-dry mass of equilibrated grain samples in accordance with ASABE S352.
Chilled-Mirror Dew-Point Water Activity Meter
Verifies equilibrium headspace relative humidity with ±0.003 a_w precision.
FOLLOW THE METHOD
A reason behind every step.
Determine the equilibrium moisture content (EMC) of agricultural cereal grain at constant temperature across variable relative humidities and calibrate the Modified Henderson sorption isotherm model. Standardized parameter settings: -2.25, -1.71, -1.17, -0.63, -0.09, 0.45 transformed.
01
Saturated Salt Solution Preparation
Prepare analytical saturated salt solutions (LiCl, MgCl₂, K₂CO₃, NaNO₂, NaCl, KCl) with excess undissolved crystals in six sealed desiccator jars to establish standard relative humidities: 11.3%, 32.8%, 43.2%, 64.3%, 75.3%, and 84.3% at 25.0°C.
02
Grain Sample Weighing & Loading
Weigh exactly 10.000 g of pre-wetted corn kernels into perforated stainless steel baskets, suspending one basket in the vapor headspace of each sealed salt jar.
03
Isothermal Incubation
Place all sealed desiccator jars inside the 25.0°C environmental incubator, leaving undisturbed for 21 days to ensure complete vapor-solid thermodynamic equilibrium.
04
Equilibrium Mass Verification
Weigh sample baskets every 48 hours until consecutive readings over 4 days show mass stability within ±0.002 g, confirming asymptotic EMC.
05
Oven Bone-Dry Determination
Transfer equilibrated grain samples into the 103°C oven for 72 hours to determine bone-dry mass and calculate dry-basis equilibrium moisture content M_e (%).
06
Modified Henderson Model Linearization
Transform RH and M_e into ln[-ln(1 - RH)] and ln(M_e), plot the linearized relationship, and evaluate Henderson parameters c_h and K_h via linear regression.
YOUR NOTEBOOK · 0 OBSERVATIONS
Turn measurements into agricultural engineering insight.
Points are your recorded observations. The solid regression line validates Equilibrium Moisture Isotherms mathematical scaling.
LINEAR REGRESSION FIT · y = mx + b
ln(M_e) = c_h · ln(-ln(1 - RH)) + ln(K_h) = 0.5200 · ln(-ln(1 - RH)) + 2.1000
| # | Transformed Relative Humidity ln(-ln(1 - RH)) (transformed) | Logarithm of Equilibrium Moisture ln(M_e) (ln(%)) | ln(-ln(1 - RH)) | ln(Equilibrium moisture M_e in %) | Remove |
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