Physical Transformation AtlasPTA
Pathway · p-24025be464 · candidate

Chemical potential difference → Electrical work

Chemical potential differenceCombustionTemperature gradientThermoacoustic effectAcoustic waveAcoustoelectric effectCharge carriersElectrical work

Epistemic state of the route

known constituent relations
5 / 7 established or replicated · weakest constituent demonstrated
constituent maturity floor
K4 · experimentally observed
search for this exact route
Not assessed — complete composition not searched.
recorded-pathway overlap
none recorded
route-level evidence
0 sources for the complete composition · 10 cited by the constituent steps
boundaries and interfaces
BOUNDARY unresolved · 1 theoretical interface
  • thermoacoustic-acoustoelectric-gas-solid · gas–solid acoustic boundary · theoretical · resonator-gas → acoustoelectric-solid · carries Acoustic wave · preserves acoustic:travelling-wave · between thermoacoustic-produces-travelling-sound and acoustic-wave-drives-acoustoelectric
    I₂ = T_I I₁; T_I = 4 Z₁ Z₂ / (Z₁ + Z₂)^2 — ideal plane boundary at normal incidence; Z₁ and Z₂ are the characteristic acoustic impedances of the gas and the solid; matching layers, finite geometry and dissipative losses neglected
    the travelling gas-borne acoustic wave mechanically loads the acoustoelectric solid directly; an electrically driven piezoelectric or IDT launcher would instead create a longer-chain implementation
    Zheng 2022 physically demonstrates direct thermoacoustic gas-wave coupling into a solid piezoelectric membrane, establishing that an active intermediate launcher is not required. No experiment is recorded in which this boundary directly drives a Weinreich-type semiconductor; the ideal transmission relation is a model for the candidate interface, not a measured datum — for 30-bar helium (Z ≈ 4.9 × 10³ Pa·s/m) on germanium (≈ 2.9 × 10⁷ Pa·s/m) it gives T_I ≈ 7 × 10⁻⁴, an illustration only.

Explorematrix context · physics checks · steps · route evidence · constituent evidence · cite

Matrix context

D = disequilibrium row · C = coupling family column. A cell reads the state of the atlas for that pair.

D.05 × C.29 · Chemical potential difference × Thermochemicalfamily: ThermochemicalD.05 × C.03 · Chemical potential difference × Thermoacousticfamily: ThermoacousticD.05 × C.35 · Chemical potential difference × Acoustoelectricfamily: Acoustoelectric

Typed bounds on this route

Every limit the atlas holds for this route, as constraint records: reached through bounded_by claims on the route's own entities. Hard bounds (an upper bound or a formula) decide the thermodynamic-bound check above; benchmarks, constitutive relations and resource limits are listed and never decisive. No prose limit exists anywhere (pass 42).

  • Carnot limit · formula-bound · hard, applies to this route
    η ≤ 1 − T_c/T_h for any heat engine between reservoirs at T_h and T_c

Steps

  1. 01
    chemical → thermal · loss to radiative
    • fuel, oxidiser and an ignition source; flame temperature 1500–2500 K
    gas · above ~700 K
    refs [1]
  2. 02
    thermal → thermal
    refs [1]
  3. 03
    thermal → acoustic · loss to thermal
    |∇T_crit| = β T_m ω |p₁| / (ρ_m c_p |u₁|); prime-mover onset requires |∇T| > |∇T_crit| · critical-gradient factor β T_m ω/(ρ_m c_p u₁) [K/(Pa·m)]
    p₁ and u₁ are the local first-order acoustic pressure and particle-velocity amplitudes; β is the volumetric thermal expansion coefficient (β T_m ≈ 1 for an ideal gas); this is the linear short-stack / standing-wave criterion of Swift 1988 — above the critical gradient the stack amplifies the wave, below it the same interaction pumps heat — not a closed-form performance law for every travelling-wave regenerator.
    • temperature gradient along the stack steeper than the critical gradient set by the acoustic pressure and displacement amplitudes
    • a resonant gas column
    gas · temperature gradient required
    refs [2]
  4. 04
    acoustic → acoustic
    • travelling-wave thermoacoustic regime with a non-zero time-averaged acoustic power flux; pressure and particle velocity have the phase relation required for directed acoustic power (a looped tube or a travelling-wave regenerator), unlike the standing wave of a straight resonator
    gas
    refs [3] [4]
  5. 05
    acoustic → electrical · loss to thermal
    |j_AE| = μ |Γ| I_s / v_s · Weinreich acoustoelectric responsivity μ Γ / v_s [A/W]
    I_s is positive along the acoustic wavevector and Γ > 0 is the intensity attenuation coefficient due to the carriers; momentum transfer is along propagation, so electron drift gives conventional current opposite to propagation while hole current is along it — the magnitude form keeps the carrier sign out of μ.
    • a travelling longitudinal bulk acoustic wave propagates through a semiconductor, or a travelling surface acoustic wave is coupled to mobile carriers
    • net DC Weinreich drag requires directed acoustic momentum; a pure standing wave does not by itself supply the required net momentum
    • a gas-borne acoustic wave may couple mechanically into the solid at a gas–solid boundary; an active piezoelectric launcher is an optional implementation, not part of the acoustoelectric effect
    solid · semiconductor required
    refs [5] [6] [7] [8] [9]
  6. 06
    electrical → electrical
    refs [5] [6]
  7. 07
    Charge carriers —converts into→ Electrical workestablishedclaim record
    electrical → electrical · loss to thermal
    • carriers driven through an external load at the potential difference the source maintains
    refs [10]

Evidence for the complete composition · 0

No source on record for this exact composition. The sources below support the individual steps, not the route as a whole.

Evidence for the constituent relations · 10

  1. [1]
    A. Bejan. Advanced Engineering Thermodynamics (4th ed.) (2016)
    Wiley · doi:10.1002/9781119245964 · crossref ✓ 2026-09-19 · record
  2. [2]
    G. W. Swift. Thermoacoustic engines (1988)
    Journal of the Acoustical Society of America 84, 1145–1180 · doi:10.1121/1.396617 · crossref ✓ 2026-09-19 · record
  3. [3]
    T. Yazaki et al.. Traveling Wave Thermoacoustic Engine in a Looped Tube (1998)
    Physical Review Letters 81, 3128–3131 · doi:10.1103/PhysRevLett.81.3128 · record
  4. [4]
    S. Backhaus, G. W. Swift. A thermoacoustic-Stirling heat engine: Detailed study (2000)
    Journal of the Acoustical Society of America 107, 3148–3166 · doi:10.1121/1.429343 · record
  5. [5]
    G. Weinreich, H. G. White. Observation of the Acoustoelectric Effect (1957)
    Physical Review 106, 1104-1106 · doi:10.1103/PhysRev.106.1104 · crossref ✓ 2026-09-20 · record
  6. [6]
    R. H. Parmenter. The Acousto-Electric Effect (1953)
    Physical Review 89, 990-998 · doi:10.1103/PhysRev.89.990 · crossref ✓ 2026-09-20 · record
  7. [7]
    G. Weinreich. Ultrasonic Attenuation by Free Carriers in Germanium (1957)
    Physical Review 107, 317–318 · doi:10.1103/PhysRev.107.317.2 · record
  8. [8]
    G. Weinreich, T. M. Sanders, H. G. White. Acoustoelectric Effect in n-Type Germanium (1959)
    Physical Review 114, 33–44 · doi:10.1103/PhysRev.114.33 · record
  9. [9]
    M. Atashbar et al.. Observation of giant acoustoelectric currents in graphene on lead magnesium niobate–lead titanate (2026)
    Nature Communications 17, 8932 · doi:10.1038/s41467-026-74813-3 · record
  10. [10]
    N. W. Ashcroft, N. D. Mermin. Solid State Physics (1976)
    Holt, Rinehart and Winston · book, no DOI · record

Cite this route

Physical Transformation Atlas (2026). route p-24025be464: Chemical potential difference → Combustion → Temperature gradient → Thermoacoustic effect → Acoustic wave → Acoustoelectric effect → Charge carriers → Electrical work. Dataset revision rbfbfcbb70e57 (hash of the canonical data). https://physical-transformation-atlas.wldud5192.workers.dev/path/24025be464

Ids and matrix addresses are stable across revisions; the revision hash identifies the exact canonical files the record was compiled from and is meta.data_hash in every /api export. Reuse terms: see the license field in any export.