Source: https://guthlabs.ai/docs/instruments/isothermal-adiabatic-polytropic-process-calculator/implementation/

instrument implementation / implementation-contract

# Isothermal / Adiabatic / Polytropic Process Calculator implementation

A source-bound implementation contract for Isothermal / Adiabatic / Polytropic Process Calculator; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t2-024

**Effect**: Computation or source lookup only

## Input and validation requirements

The adiabatic formula is undefined at gamma = 1 because its denominator gamma - 1 vanishes. If the calculator accepts gamma = 1 instead of rejecting it, it may emit NaN, Infinity, or an inconsistent result.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "process_type": "isothermal",
    "n_moles": 1,
    "T1_K": 300,
    "V1_m3": 0.01,
    "V2_m3": 0.02,
    "R_J_per_molK": 8.314
  },
  "expected_outputs": {
    "P1_Pa": 249420,
    "P2_Pa": 124710,
    "T2_K": 300,
    "work_by_gas_J": 1728.85,
    "heat_into_gas_J": 1728.85,
    "delta_U_J": 0
  },
  "working": "P1=nRT/V1=(1×8.314×300)/0.01=249420 Pa. P2=nRT/V2=(1×8.314×300)/0.02=124710 Pa. T2=T1=300 K. W=nRT ln(V2/V1)=(1×8.314×300)ln(0.02/0.01)=2494.2×ln(2)=2494.2×0.69314718=1728.85 J. For an ideal-gas isothermal process, ΔU=0, so Q=W=1728.85 J."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/isothermal-adiabatic-polytropic-process-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/isothermal-adiabatic-polytropic-process-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/isothermal-adiabatic-polytropic-process-calculator/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche2/tranche2-results.json`