Pathway · p-62809bc294 · candidate

Temperature gradient → Electrical work

Temperature gradientMarangoni effectMechanical motionRotating-machine generator actionCharge carriersElectrical work

Epistemic state of the route

known constituent relations: 5 / 5 established or replicated · weakest constituent replicated
constituent maturity floor: K4 · experimentally observed
search for this exact route: Exact composition search: reviewed 2026-09-21 — partial; No demonstration known and none found: nothing OpenAlex returned closes the chain from a temperature gradient through a thermocapillary-driven body to a rotating generator. The two halves the atlas already records stand on their own evidence (thermal Marangoni gears and floaters that move; a Marangoni rotor turning a generator under a solutal source), and the literature between them is convection, heat transfer and micromotors. Inconclusive as a route search until the Scholar and Semantic Scholar runs exist.
recorded-pathway overlap: shares relations, in order, with Thermocapillary micromotor · 2/5 relations shared
route-level evidence: 0 sources for the complete composition · 8 cited by the constituent steps
boundaries and interfaces: BOUNDARY compatible · no region transition

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.01 × C.34 · Temperature gradient × Marangoni family: MarangoniD.01 × C.14 · Temperature gradient × Electromagnetic induction family: Electromagnetic induction

Literature search for this exact composition

Reviewed search · 2026-09-21OpenAlexpartial

No demonstration known and none found: nothing OpenAlex returned closes the chain from a temperature gradient through a thermocapillary-driven body to a rotating generator. The two halves the atlas already records stand on their own evidence (thermal Marangoni gears and floaters that move; a Marangoni rotor turning a generator under a solutal source), and the literature between them is convection, heat transfer and micromotors. Inconclusive as a route search until the Scholar and Semantic Scholar runs exist.

6 runs · 5 attempts blocked before any result (Semantic Scholar, Google Scholar) — attempted, never counted · 150 unique records · 0 read in full · reviewed by Ava Kim's loop-3 lane · protocol route-search-v1

Striking features of fluid flows in taylor cones related to electrosprays (1994) · wrong coupling · Shtern & Barrero 1994 (J. Aerosol Sci. 25, 1049–1063): the mechanism-pair form's only hit, an electrospray Taylor-cone flow paper that matches a generator term incidentally; no rotating generator, no thermal Marangoni rotor.
Collective Oscillations of Photothermal Micromotors under Static Illumination (2026) · constituent only · Wang et al. 2026 (Langmuir 42, 21207–21216): photothermal micromotors whose light-made temperature difference moves them by self-thermophoresis and thermocapillary forces (≈ 70 μm/s) and by thermal convection (≈ 2422 μm/s) in an oscillating collective — the thermal Marangoni → motion half, no generator.
Racing-car-inspired electrical/chemical dual-driven actuators for swimming Marangoni robots based on carbon nanotube composites (2026) · wrong driver · Nano Research 2026: swimming Marangoni robots driven electrically and chemically, by title; not a temperature gradient, no generator.
A Tunable Island-Structured Bioinspired Interfacial Evaporator for Efficient Seawater Desalination and Energy Harvesting (2026) · wrong coupling · Mu et al. 2026 (Adv. Funct. Mater. 36, e75319): a solar interfacial evaporator whose salt tolerance relies on solutal and thermal Marangoni convection, with a thermal module harvesting the evaporation's waste heat at up to 1.083 W m⁻² — the harvesting is thermoelectric, the Marangoni flow moves salt, not a rotor.
Magnetohydrodynamics Thermocapillary Marangoni Convection Heat Transfer of Power-Law Fluids Driven by Temperature Gradient (2013) · simulation only · Lin, Zheng & Zhang 2013 (J. Heat Transfer 135, 051702): numerical solutions for MHD thermocapillary convection of a power-law fluid under a temperature gradient — heat transfer, no body, no generator.

Limitations: OpenAlex only (21/09, 10:49 am Sydney): driver-mechanism 1,424 works reported, the first 100 by relevance and the first 50 newest screened at title level (protocol depth), the rest unscreened; mechanism-pair 1, whole-chain 0, demonstration-precision 0, the reviewer's precision query 0; Semantic Scholar answers 429 keyless (owner exception e953) and Google Scholar a captcha — both mandatory for a negative, neither run no composition term is frozen because no recorded source names a thermocapillary generator as a device; if the literature holds such a name the composite-name form becomes mandatory once it is added with its source the driver-mechanism list is thermocapillary convection and heat transfer (crystal growth, welding pools, films), Marangoni micromotors and robots, and evaporators; nothing on it turns a rotor or a generator with a temperature gradient pass 49 (21/09 ~11:29 pm Sydney): every planned Semantic Scholar query was attempted once through the anonymous pool — 4 of 4 answered HTTP 429 at the first request (the runs above, each with its literal query, key and time); Google Scholar served its bot check at the first load of the driver-mechanism form (recorded as an attempt with nothing screened). Both engines are mandatory for a negative under route-search-v1, so the record stays partial and inconclusive: the outstanding obligations are the Semantic Scholar runs for every mandatory key and the Google Scholar runs to the protocol depth; OpenAlex's forms are complete. A blocked request is evidence that an engine was attempted, never that its query returned nothing.

Index query only · 2026-09-21OpenAlex · 6 queriesnot reviewed

2849 indexed works reported across the queries, 150 unique retrieved; nobody has read them for a qualifying demonstration. A person can screen this frozen list and promote it to a reviewed record without re-running the query.

OAdriver-mechanism:11424 reported · 100 retrieved
OAdriver-mechanism:11424 reported · 50 retrieved
OAmechanism-pair:1-21 reported · 1 retrieved
OAwhole-chain0 reported · 0 retrieved
OAdemonstration-precision0 reported · 0 retrieved
OAdemonstration-precision0 reported · 0 retrieved

Planned runs NOT run in this bundle (engine unavailable): search:2026-09-21-p-62809bc294/s2-dm1 (semantic-scholar); search:2026-09-21-p-62809bc294/s2-mp12 (semantic-scholar); search:2026-09-21-p-62809bc294/s2-wc (semantic-scholar); search:2026-09-21-p-62809bc294/s2-dp (semantic-scholar).

Protocol route-search-v1: a frozen index run changes only the search state; only a reviewed record can say that a demonstration was or was not found.

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

01
Temperature gradient —drives→ Marangoni effectestablishedclaim record
thermal → kinetic · loss to thermal
- thermocapillary case: surface tension falls with temperature, so a temperature gradient along the interface drives flow toward the cold side
liquid · temperature gradient required
refs [1] [2]
02
Marangoni effect —produces→ Mechanical motionreplicatedclaim record
kinetic → mechanical · loss to thermal
- a floating or interface-bound body whose asymmetry (shape, or where it emits a surfactant or absorbs heat) leaves a net surface-tension force or torque on it
- the body must be free to move on the interface; a rigid wall only sets up a flow
liquid
Two independent groups: thermocapillary microgears (Maggi et al. 2015, light-heated, up to 300 r.p.m.) and solutocapillary camphor rotors carrying magnets past a coil (Frenkel et al. 2019, 10–20 h). Distinct from Marangoni flow turning a rotor: here the Marangoni stress acts on the moving body directly.
refs [3] [4]
03
Mechanical motion —drives→ Rotating-machine generator actionestablishedclaim record
mechanical → electrical · loss to thermal
- a shaft turning a rotor inside a stator, or a magnet moved past a coil
conductor required · magnetic field required
refs [5] [6]
04
Rotating-machine generator action —produces→ Charge carriersestablishedclaim record
electrical → electrical · loss to thermal
refs [5] [7]
05
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 [8]

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 · 8

[1]
L. E. Scriven, C. V. Sternling. The Marangoni Effects (1960)
Nature 187, 186-188 · doi:10.1038/187186a0 · crossref ✓ 2026-09-20 · record
[2]
Q. Dai et al.. Directional interfacial motion of liquids: Fundamentals, evaluations, and manipulation strategies (2021)
Tribology International 154, 106749 · doi:10.1016/j.triboint.2020.106749 · crossref ✓ 2026-09-20 · record
[3]
C. Maggi et al.. Micromotors with asymmetric shape that efficiently convert light into work by thermocapillary effects (2015)
Nature Communications 6, 7855 · doi:10.1038/ncomms8855 · record
[4]
M. Frenkel et al.. Mini-Generator of Electrical Power Exploiting the Marangoni Flow Inspired Self-Propulsion (2019)
ACS Omega 4, 15265–15268 · doi:10.1021/acsomega.9b02257 · record
[5]
M. Faraday. Experimental researches in electricity (1832)
Philosophical Transactions of the Royal Society 122, 125–162 · doi:10.1098/rstl.1832.0006 · crossref ✓ 2026-09-19 · record
[6]
S. L. Dixon, C. A. Hall. Fluid Mechanics and Thermodynamics of Turbomachinery (7th ed.) (2014)
Butterworth-Heinemann · doi:10.1016/C2011-0-05059-7 · crossref ✓ 2026-09-19 · record
[7]
L. D. Landau, E. M. Lifshitz, L. P. Pitaevskii. Electrodynamics of Continuous Media (Course of Theoretical Physics, Vol. 8, 2nd ed.) (1984)
Pergamon · book, no DOI · record
[8]
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-62809bc294: Temperature gradient → Marangoni effect → Mechanical motion → Rotating-machine generator action → Charge carriers → Electrical work. Dataset revision rbfbfcbb70e57 (hash of the canonical data). https://physical-transformation-atlas.wldud5192.workers.dev/path/62809bc294

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.