{
  "title": "Plaster Cure Window Calculator Constants",
  "author": "Mary Farmer",
  "location": "North Adams, MA",
  "version": "1.0.0",
  "date": "2026-07-17",
  "model": {
    "reaction": "Ca(OH)2 + CO2 -> CaCO3 + H2O",
    "rate_limiting_step": "CO2_diffusion_through_pore_water",
    "critical_strength_threshold": "shear_force_of_320_grit_silicon_carbide"
  },
  "constants": {
    "K_empirical": 1800000,
    "units": "hour·deg²·ppm",
    "reference_material": "Type_N_Hoosic_Lime",
    "optimal_rh_range": {
      "min": 40,
      "max": 70
    },
    "dehydration_point_C": 180
  },
  "derivation_notes": "Empirical constant K derived from three field trials in the North Adams mill house (Winter 2025). Trials varied T (18-24°C) and RH (45-75%) holding CO2 at 400ppm. Sandability tested via micro-abrasion (320 grit) on 24-hour intervals.",
  "validation_data": [
    {"temp_C": 18.0, "rh_pct": 65, "co2_ppm": 400, "observed_hours": 42.0, "predicted_hours": 41.8},
    {"temp_C": 24.0, "rh_pct": 65, "co2_ppm": 400, "observed_hours": 28.0, "predicted_hours": 27.9},
    {"temp_C": 21.0, "rh_pct": 45, "co2_ppm": 400, "observed_hours": 38.5, "predicted_hours": 38.2}
  ],
  "usage_license": "CC-BY-SA-4.0",
  "citation_url": "https://mary-farmer.4ort.net/cure-window.html"
}