{"schema_version":1,"experiment_id":"eoa_inverse_innovation_exp12_substrate_denial72_20260805","cell_id":"backcasting_pathway_design__chemistry_materials","arm":"CONSTRAINED_HIGH","candidate_id":"backcasting_pathway_design__chemistry_materials__CONSTRAINED_HIGH","decision":"PROPOSAL","abstention_reason":null,"proposal":{"schema_version":1,"experiment_id":"eoa_inverse_innovation_exp12_substrate_denial72_20260805","cell_id":"backcasting_pathway_design__chemistry_materials","arm":"CONSTRAINED_HIGH","candidate_id":"backcasting_pathway_design__chemistry_materials__CONSTRAINED_HIGH","proposal_index":1,"version":0,"title":"Reverse-derived precursor grading for uniform post-sinter ceramic stoichiometry","problem":"A lithium-containing ceramic compact fired under a fixed thermal schedule can finish with a lithium-depleted surface region and a compositionally different interior because volatilization is strongest near exposed surfaces while solid-state and grain-boundary transport redistribute lithium during firing. Starting with a spatially uniform precursor mixture may therefore reproduce a nonuniform terminal composition even when the desired fired state is a uniform target phase and stoichiometry.","actors":["Ceramic-processing researcher","Laboratory technician","Lithium-containing green ceramic compact","Lithium-bearing precursor reservoirs","Furnace atmosphere and crucible","Volatile lithium species"],"observable_state":"Cross-sectional measurements of fired coupons show whether lithium-to-framework-element ratio, phase assemblage, density, and microstructure vary systematically with depth from an exposed surface under a repeatable firing schedule.","consequence":"A depleted shell or internal secondary-phase region can make the fired body fail its specified condition of spatially uniform target phase and composition, compromising interpretation or use of its material properties.","affected_objective":"Produce a fired ceramic coupon whose depth-resolved composition and phase meet a predefined uniformity criterion without changing the selected bulk firing schedule.","intervention":"Fabricate a green compact as several mechanically consolidated powder layers with deliberately different lithium-precursor fractions. Derive the fractions backward from the desired post-firing depth profile: for each firing interval, add back the lithium expected to leave each depth zone and account for exchange with adjacent zones, continuing backward until an initial layer composition is obtained. During firing, the lithium-enriched near-surface layers act as finite material reservoirs; volatilization, diffusion, and phase reaction consume and redistribute their excess so that the terminal profile approaches the specified uniform state. The physical graded compact, rather than its design worksheet, is the operative intervention.","structural_mapping":[{"archetype_element":"Desired Future State","domain_realization":"A fired coupon with the specified target phase and lithium-to-framework-element ratio across defined depth zones."},{"archetype_element":"Future Success Criteria","domain_realization":"Predeclared tolerances for depth-resolved composition, phase identity, density, absence of lithium-rich secondary phases, and coupon integrity."},{"archetype_element":"Baseline Current State","domain_realization":"A uniformly mixed stoichiometric green compact fired in an open lidded crucible using the fixed reference schedule."},{"archetype_element":"Prerequisite Condition","domain_realization":"Immediately before each firing interval, every depth zone contains enough mobile lithium to cover its subsequent volatilization loss, phase demand, and net transfer to neighboring zones."},{"archetype_element":"Reverse Milestone","domain_realization":"A required depth-by-depth composition profile at each earlier thermal interval, obtained by adding anticipated downstream losses and transfers back to the later required state."},{"archetype_element":"Dependency Map","domain_realization":"A physical mass-balance network linking adjacent depth zones and successive thermal intervals through volatilization, diffusion, and phase incorporation."},{"archetype_element":"Present Commitment","domain_realization":"Press a bounded set of multilayer coupons with the reverse-derived precursor fractions and matched uniform controls."},{"archetype_element":"Monitoring Trigger","domain_realization":"A measured secondary phase, delamination, excessive mass loss, or profile inversion triggers rejection or revision of the layer design rather than silent relaxation of the terminal criterion."}],"mechanism_mapping":[{"mechanism_slug":"surface_localized_volatilization","role":"Creates the depth-dependent material loss that makes a uniform starting composition an inadequate pathway to the uniform terminal state.","counterfactual_removal":"If volatilization is absent or spatially uniform, the motivating terminal gradient should disappear and precursor grading should provide no specific advantage."},{"mechanism_slug":"chemical_potential_driven_lithium_transport","role":"Moves lithium between adjoining layers during heating, allowing finite enriched zones to supply depleted zones rather than remaining isolated inclusions.","counterfactual_removal":"If interlayer transport is negligible on the firing timescale, the enriched layers should remain compositionally distinct and the intended convergence toward a uniform terminal profile should fail."},{"mechanism_slug":"finite_precursor_reservoir_depletion","role":"Converts backward-specified local excess into transient supply that is consumed by volatilization and target-phase formation.","counterfactual_removal":"If the added precursor neither releases mobile lithium nor enters the intended phase pathway, the graded compact cannot compensate the loss profile."},{"mechanism_slug":"sequential_phase_incorporation","role":"Locks redistributed lithium into the desired ceramic phase as temperature advances, realizing the successive prerequisite states physically.","counterfactual_removal":"If competing phases irreversibly capture the redistributed lithium, satisfying an earlier composition state will not enable the desired later state."}],"causal_chain":["Define the terminal material state as a measurable depth profile rather than a nominal bulk recipe.","Under the fixed firing schedule, measure stage- and depth-dependent mass loss, composition, and phase state in calibration coupons.","Work backward from the terminal criterion through successive thermal intervals to specify the material inventory required immediately before each interval.","Translate the nearest required state into a present green-body architecture with discrete precursor concentrations by depth.","When heated, enriched layers release mobile lithium while exposed regions lose lithium to the atmosphere.","Diffusion and grain-boundary transport redistribute the released lithium, and phase reactions incorporate it as the firing sequence progresses.","If the reverse material balance is adequate, the initially graded precursor inventory converges toward the specified uniform fired profile; destructive cross-sectional measurements test that result."],"baseline":"Uniformly mixed stoichiometric powder pressed to the same geometry and fired with the same crucible, atmosphere, loading, and thermal schedule. It is compared by pre/post mass, depth-resolved composition, phase mapping, density, and microstructural integrity.","nearest_rivals":["A uniform lithium excess throughout the compact","A sacrificial lithium-bearing powder bed surrounding an otherwise uniform compact","A more tightly sealed or lithium-buffered crucible atmosphere","A lower-temperature or shorter firing schedule that reduces volatilization","Post-sinter lithium diffusion treatment"],"remaining_contrastive_claim":"The graded compact differs from uniform excess by placing finite precursor inventory according to backward-derived, depth-specific downstream losses and transport dependencies. It differs from atmosphere-control rivals by compensating within the body while retaining the reference furnace schedule. The claim is conditional: only if interlayer transport and phase incorporation occur on compatible timescales should the reverse-derived profile yield a terminal composition closer to the predefined target than matched uniform starting profiles.","authority_safety":{"decision_authority":"The laboratory principal investigator or designated ceramic-processing safety lead may authorize only the bounded coupon experiment after reviewing precursor hazards, furnace compatibility, ventilation, and waste handling.","authorized_first_step":"Prepare millimeter-scale calibration and graded coupons using already approved precursor quantities and an existing reviewed furnace schedule; characterize them destructively after cooling.","excluded_actions":["Scale-up beyond the reviewed coupon mass","Use of an unapproved lithium precursor or furnace atmosphere","Sealing a vessel that is not pressure-rated for the firing conditions","Disabling furnace, ventilation, or gas-monitoring interlocks","Using the material in a device or load-bearing application","Changing the terminal success criterion after observing results"],"halt_rollback":"Stop heating through the established emergency procedure if pressure, unexpected gas release, crucible attack, abnormal furnace behavior, or loss of ventilation occurs. Quarantine affected hardware and residues. If coupons show delamination, severe secondary-phase formation, or greater mass loss than controls, discontinue the graded design and return to the unchanged uniform-coupon baseline pending hazard and mechanism review."},"negative_tests":{"strongest_counterevidence":"A sacrificial powder bed or uniform excess produces the same terminal depth profile, or the fired graded coupon retains sharp lithium-rich layers, indicating that the proposed reverse-derived spatial allocation is unnecessary or physically unable to converge.","problem_falsifier":"Repeated cross-sectional measurements of uniform baseline coupons show no reproducible depth-dependent lithium depletion or phase variation beyond measurement and sampling uncertainty under the reference firing schedule.","intervention_falsifier":"Across matched firing runs, reverse-graded coupons are indistinguishable from or less uniform than uniform controls in independently measured composition and phase profiles, or enriched layers form persistent secondary phases instead of supplying depleted zones.","risks":["Lithium-rich secondary phases caused by local overcompensation","Delamination, warping, or cracking at powder-layer interfaces","Unexpected precursor decomposition, gas evolution, or powder ejection","Crucible or furnace contamination by volatile species","Operator exposure during precursor handling and sectioning","Misleading depth profiles from polishing, beam interaction, or sampling artifacts","Non-identifiability between volatilization, diffusion, and phase-reaction effects in a small experiment"]},"next_evidence_step":"Run one bounded coupon study under a single approved firing schedule: include uniform stoichiometric baseline coupons, uniform-excess coupons, a sacrificial-powder-bed rival, and two reverse-derived multilayer profiles based on calibration measurements. Randomize furnace positions, retain unfired witnesses, record pre/post mass, and obtain blinded cross-sectional composition and phase maps. Proceed only to profile refinement, not scale-up, if the motivating gradient is reproduced and at least one graded profile converges without persistent lithium-rich layers or integrity failure.","prior_art_status":"UNSEARCHED","diversity_from_prior_proposals":"Not assessed against other proposals because runtime isolation forbids inspection. This candidate is characterized internally as a materially encoded, depth-graded reaction pathway whose operative effect is volatilization compensation and solid-state transport.","revision_record":{"parent_version":null,"progress_targets_addressed":["Preserve desired-future anchoring and reverse dependency logic in a chemistry/materials realization","Make the operative intervention independently physical rather than a planning or reporting wrapper","Specify rivals, falsifiers, safeguards, and a bounded evidence step"],"conceptual_changes":[],"operational_changes":[],"evidence_changes":[],"claim_changes":[]},"substrate_contract":{"primary_allowed_process":"PHYSICAL_MATERIAL","counterfactual_independence":"Once the graded green compact has been fabricated, its essential effect survives removal of software, algorithms, databases, dashboards, reporting, incentives, authorization workflows, and procedural enforcement. Heating alone causes precursor release, volatilization, interlayer diffusion, and phase incorporation. A manually labeled or even unlabeled coupon with the same physical layer compositions would undergo the same material transformations.","forbidden_channel_audit":"No sensor, model, dashboard, recommendation, permission, incentive, training program, or human response closes the operative loop. Measurements are used only to design and evaluate a fixed coupon; they do not control it during firing. Safety authorization and furnace procedures bound exposure but do not generate the proposed compositional effect. Computation may assist the mass balance, but the causal intervention is the pre-existing spatial precursor inventory, and its removal—not removal of computation or governance—eliminates the intended effect."}}}