# Volume X — installment 1, theories 1-30 (new file)
THEORIES = [
{"n":1,"slug":"room-modes-volume-absorption","field":"Acoustics & Vibration","title":"Room Modes Follow a Volume Ratio","claim":"A room's modal density is felt only when volume per unit absorption crosses a threshold, so a large dry room can sound smaller than a small live one.","mechanism":"Absorption controls decay, volume controls mode spacing. The audible character is set by the ratio, which is why treating one alone fails to predict how a room sounds.","predictions":["Rooms matched on ratio should sound alike regardless of size.","Adding absorption should shift perceived size only past the threshold."],"refute":"Perceived size tracking volume alone would reduce the ratio to a correction."},
{"n":2,"slug":"joint-slip-damping","field":"Acoustics & Vibration","title":"Damping Is Joint Slip","claim":"Structural damping in bolted assemblies is set by micro-slip amplitude at joints rather than by material loss factors.","mechanism":"Energy leaves through friction at interfaces, so damping scales with the number of slipped joints and the amplitude of slip, not with bulk material damping.","predictions":["Damping should rise with joint count at fixed material.","Tightening joints should reduce damping until slip vanishes."],"refute":"Damping independent of joint condition would favour material loss."},
{"n":3,"slug":"cavitation-frequency-threshold","field":"Acoustics & Vibration","title":"Cleaning Is a Cavitation Threshold","claim":"Ultrasonic cleaning efficacy is set by how far the drive exceeds the cavitation threshold at that frequency, not by acoustic power.","mechanism":"Cavitation nuclei require a pressure amplitude that rises with frequency. Power above threshold is wasted as heating.","predictions":["Cleaning should track overpressure above threshold.","Doubling power at constant overpressure should not help."],"refute":"Cleaning scaling with power regardless of threshold would remove the mechanism."},
{"n":4,"slug":"noise-annoyance-derivative","field":"Acoustics & Vibration","title":"Annoyance Tracks Change","claim":"Annoyance from environmental noise follows the rate of change of exposure rather than its level, so a stable noisy area can be tolerated while a quieting area remains a complaint source.","mechanism":"Attention is drawn to change; a steady exposure fades from awareness while a rising one does not.","predictions":["Complaints should correlate with trend better than level.","Stable high exposure should generate fewer complaints than rising moderate exposure."],"refute":"Complaints tracking level at controlled trend would restore the level model."},
{"n":5,"slug":"consonance-roughness-threshold","field":"Acoustics & Vibration","title":"Consonance Is Roughness","claim":"Musical consonance is set by a roughness threshold in the auditory filter bank rather than by the simplicity of frequency ratios.","mechanism":"Ratios matter only where they produce beating within a critical band; outside that, simple and complex intervals are indistinguishable.","predictions":["Consonance should track beating within critical bands.","Timbre changes should shift consonance at fixed ratio."],"refute":"Consonance tracking ratio simplicity across timbres would favour the ratio account."},
{"n":6,"slug":"coincidence-frequency-insulation","field":"Acoustics & Vibration","title":"Insulation Fails at Coincidence","claim":"Building panel insulation collapses at a coincidence frequency set by panel mass and stiffness, so a heavier panel can insulate worse in a band.","mechanism":"At coincidence the bending wavelength matches the airborne wavelength, and the panel becomes transparent to sound.","predictions":["Insulation should dip at a predicted frequency.","Stiffening should shift the dip."],"refute":"Monotonic improvement with mass would remove the coincidence dip."},
{"n":7,"slug":"white-finger-dose-rate","field":"Acoustics & Vibration","title":"Hand-Arm Injury Is a Rate","claim":"Vibration-induced white finger is set by the rate of energy delivery to the fingers rather than by cumulative exposure, so rest breaks change outcome at equal dose.","mechanism":"Recovery competes with damage. Continuous exposure saturates recovery, while interrupted exposure allows repair between bouts.","predictions":["Interrupted exposure should cause less injury at equal total.","Recovery rate should predict severity."],"refute":"Injury tracking total dose regardless of interruption would remove the rate effect."},
{"n":8,"slug":"sonar-range-sound-speed","field":"Acoustics & Vibration","title":"Sonar Range Is the Profile","claim":"Sonar detection range is set by the curvature of the sound speed profile rather than by source level, so a louder source in a defocusing profile can detect less.","mechanism":"The profile refracts rays; a downward-refracting profile traps sound near the surface while an upward one disperses it.","predictions":["Range should track profile curvature.","Increasing source level should not overcome defocusing."],"refute":"Range scaling with source level regardless of profile would remove refraction control."},
{"n":9,"slug":"speaker-breakup-density","field":"Acoustics & Vibration","title":"Distortion Follows Breakup Density","claim":"Loudspeaker distortion is set by the density of diaphragm breakup modes rather than by the first breakup frequency, so a lower first mode with dense modes above can sound cleaner.","mechanism":"Distortion arises from intermodulation between modes; dense modes distribute energy while a sparse set produces audible peaks.","predictions":["Distortion should track mode density.","Lowering the first mode without densifying should worsen it."],"refute":"Distortion tracking the first breakup frequency would favour the simple account."},
{"n":10,"slug":"hearing-loss-kurtosis","field":"Acoustics & Vibration","title":"Hearing Loss Reads Kurtosis","claim":"Noise-induced hearing loss is predicted by the kurtosis of the exposure rather than by equal-energy dose, so impulsive noise damages more at the same energy.","mechanism":"Peaks above a threshold trigger mechanical damage that continuous sound of equal energy does not, so the distribution's shape matters.","predictions":["Kurtosis should predict loss better than Leq.","Equal-energy impulsive exposure should cause more loss."],"refute":"Loss tracking equal energy at controlled kurtosis would restore the dose model."},
{"n":11,"slug":"laser-damage-defect-density","field":"Optics & Photonics","title":"Laser Damage Counts Defects","claim":"Laser-induced damage threshold is set by absorbing defect density rather than by fluence alone, so two coatings of identical design can differ several-fold.","mechanism":"Damage initiates at absorbers that heat locally; threshold falls as the density of such sites rises.","predictions":["Threshold should scale inversely with defect density.","Identical designs should differ by coating process."],"refute":"Threshold tracking fluence limits at controlled defect density would remove the defect term."},
{"n":12,"slug":"fiber-nonlinearity-area","field":"Optics & Photonics","title":"Nonlinearity Is an Area Ratio","claim":"The onset of nonlinear impairment in fibre links is set by the ratio of launch power to effective mode area rather than by power.","mechanism":"Intensity drives nonlinearity; larger effective area spreads the same power over more glass.","predictions":["Impairment should collapse onto the power-to-area ratio.","Larger-area fibre should tolerate more power."],"refute":"Impairment tracking power at fixed area would leave area irrelevant."},
{"n":13,"slug":"led-droop-density","field":"Optics & Photonics","title":"Droop Begins at a Density","claim":"LED efficiency droop begins at a carrier density threshold where Auger recombination overtakes radiative recombination, so the onset current scales with active volume.","mechanism":"Auger is cubic in carrier density while radiative recombination is quadratic, so a crossover exists.","predictions":["Droop onset should scale with active volume.","Devices with larger volumes should droop later."],"refute":"Droop onset independent of volume would favour a field-driven mechanism."},
{"n":14,"slug":"hologram-coherence-depth","field":"Optics & Photonics","title":"Holograms Need Coherence Depth","claim":"Holographic image quality is set by coherence length relative to scene depth rather than by laser power, so a deep scene needs a longer coherence length.","mechanism":"Interference requires path differences within coherence; beyond it, fringes wash out.","predictions":["Image quality should fall when depth exceeds coherence.","Longer coherence should extend usable depth."],"refute":"Quality independent of coherence at fixed depth would remove the constraint."},
{"n":15,"slug":"oct-anisotropy","field":"Optics & Photonics","title":"Imaging Depth Is Anisotropy",
"claim":"Optical coherence tomography penetration is set by the scattering anisotropy factor rather than by scattering coefficient alone, so a highly forward-scattering tissue can be imaged deeper.","mechanism":"Anisotropy determines how many scattering events a photon survives before losing direction, which sets effective penetration.","predictions":["Depth should track anisotropy at matched coefficient.","Forward-scattering media should image deeper."],"refute":"Depth tracking the coefficient alone would leave anisotropy irrelevant."},
{"n":16,"slug":"photonic-crosstalk-contrast","field":"Optics & Photonics","title":"Crosstalk Is an Index Ratio","claim":"Crosstalk between photonic waveguides is set by the ratio of index contrast to spacing rather than by spacing alone, so a tighter spacing can be tolerated with higher contrast.","mechanism":"Mode overlap decays exponentially with the ratio of spacing to confinement, and confinement is set by contrast.","predictions":["Crosstalk should collapse onto the ratio.","Higher contrast should permit tighter spacing."],"refute":"Crosstalk depending on spacing alone would remove the contrast term."},
{"n":17,"slug":"lens-flare-scatter-correlation","field":"Optics & Photonics","title":"Flare Follows Scatter Correlation","claim":"Lens flare is set by the spatial correlation of coating scatter rather than by total scatter, so a coating with more scatter arranged randomly can flare less than a smoother but correlated one.","mechanism":"Flare is coherent within a point spread function; correlated scatter adds in phase while random scatter averages.","predictions":["Flare should track correlation length.","Total scatter should predict poorly."],"refute":"Flare tracking total scatter would remove the correlation effect."},
{"n":18,"slug":"pulse-compression-gain-narrowing","field":"Optics & Photonics","title":"Compression Hits a Gain Limit","claim":"The shortest pulse achievable in a chirped-pulse amplifier is set by gain narrowing rather than by the seed bandwidth.","mechanism":"Amplification narrows the spectrum toward the gain peak, so the output bandwidth is set by the amplifier even when the seed is broader.","predictions":["Pulse duration should plateau with seed bandwidth.","Flattening the gain should shorten pulses."],"refute":"Pulses continuing to shorten with seed bandwidth would remove gain narrowing."},
{"n":19,"slug":"interferometer-air-turbulence","field":"Optics & Photonics","title":"Interferometry Reads the Air","claim":"Interferometric measurement error is set by the correlation length of air turbulence rather than by its magnitude, so strong but fine-grained turbulence can matter less than weak and coarse.","mechanism":"The beam averages over turbulence; features larger than the beam path are not averaged out.","predictions":["Error should track correlation length.","Fine turbulence should average out."],"refute":"Error tracking turbulence magnitude would remove the scale dependence."},
{"n":20,"slug":"gamut-primary-width","field":"Optics & Photonics","title":"Gamut Is Primary Width","claim":"A display's colour gamut is set by the spectral width of its primaries rather than by their peak wavelength.","mechanism":"Gamut corners are defined by the chromaticity of each primary, which broadens as the spectrum widens.","predictions":["Gamut should fall as primary width rises.","Narrow primaries at the same peaks should extend gamut."],"refute":"Gamut tracking peak wavelength alone would favour the simple account."},
{"n":21,"slug":"casting-gradient-rate","field":"Materials Processing","title":"Porosity Is a Gradient Ratio","claim":"Casting porosity is set by the ratio of thermal gradient to solidification rate rather than by either alone.","mechanism":"The ratio sets the mushy zone length; a long zone traps feeding paths and produces shrinkage porosity.","predictions":["Porosity should collapse onto the ratio.","Fast solidification with a shallow gradient should still be porous."],"refute":"Porosity tracking solidification rate alone would remove the ratio."},
{"n":22,"slug":"forging-chill-depth","field":"Materials Processing","title":"Forging Stress Is Chill Depth","claim":"Residual stress in a forging is set by the depth of die chilling during the final blows rather than by the overall forging load.","mechanism":"A cold skin resists contraction relative to the hot core, which produces the stress pattern; depth of that skin sets magnitude.","predictions":["Stress should track chill depth.","Load changes at fixed chill should matter less."],"refute":"Stress tracking forging load would remove the chill mechanism."},
{"n":23,"slug":"heat-treat-distortion-time","field":"Materials Processing","title":"Distortion Is Hold Time","claim":"Heat-treatment distortion is set by austenitizing hold time rather than by peak temperature, because grain growth during the hold redistributes transformation strain.","mechanism":"Longer holds coarsen grains, and coarse grains transform inhomogeneously, concentrating strain into distortion.","predictions":["Distortion should rise with hold time.","Peak temperature at fixed hold should matter less."],"refute":"Distortion tracking peak temperature would remove the time mechanism."},
{"n":24,"slug":"coating-adhesion-wavelength","field":"Materials Processing","title":"Adhesion Is Roughness Wavelength","claim":"Coating adhesion is maximal at an intermediate substrate roughness wavelength rather than at maximum roughness.","mechanism":"Mechanical keying requires features the coating can penetrate; features too coarse leave voids at valleys.","predictions":["Adhesion should peak at a roughness wavelength.","Smoother and rougher substrates should both perform worse."],"refute":"Monotonic adhesion with roughness would remove the optimum."},
{"n":25,"slug":"compaction-contact-percolation","field":"Materials Processing","title":"Compaction Is a Contact Network","claim":"Powder compaction density rises sharply at a percolation threshold in the contact network rather than smoothly with pressure.","mechanism":"Below threshold the network is floppy and rearranges easily; above it, stress transmits through a spanning cluster and further densification requires particle fracture.","predictions":["Density should jump at a threshold pressure.","Compressibility should change slope at percolation."],"refute":"Smooth density-pressure curves would remove the threshold."},
{"n":26,"slug":"chatter-depth-width","field":"Materials Processing","title":"Chatter Is a Width Ratio","claim":"Machining chatter begins at a critical ratio of depth of cut to tool engagement width rather than at a critical depth.","mechanism":"Stability depends on the dynamic compliance at the cutting point, which scales with engagement geometry rather than absolute depth.","predictions":["Stability should collapse at a width ratio.","Absolute depth alone should not predict onset."],"refute":"Chatter tracking absolute depth would remove the ratio."},
{"n":27,"slug":"brazing-intermetallic-thickness","field":"Materials Processing","title":"Brazed Joints Peak at a Layer","claim":"Brazed joint strength peaks at an intermediate intermetallic layer thickness, weakening both thinner and thicker.","mechanism":"Too thin gives incomplete bonding; too thick gives a brittle layer that cracks under load.","predictions":["Strength should peak at a thickness.","Both extremes should fail differently."],"refute":"Monotonic strength with thickness would remove the optimum."},
{"n":28,"slug":"die-swell-relaxation","field":"Materials Processing","title":"Die Swell Is a Time Ratio","claim":"Polymer extrudate swell is set by the ratio of relaxation time to residence time in the die, not by shear rate alone.","mechanism":"Recoverable strain stored in the melt relaxes before exit if the residence time is long, reducing swell.","predictions":["Swell should collapse onto the ratio.","Longer dies should reduce swell at fixed rate."],"refute":"Swell tracking shear rate alone would remove the relaxation term."},
{"n":29,"slug":"sintering-dihedral-angle","field":"Materials Processing","title":"Shrinkage Follows Dihedral Angle","claim":"Sintering shrinkage is set by the distribution of dihedral angles rather than by mean particle size.","mechanism":"The dihedral angle sets the capillary driving force; a distribution with more low-angle necks densifies faster at the same size.","predictions":["Shrinkage should track the angle distribution.","Particle size should matter less."],"refute":"Shrinkage tracking particle size would remove the angle control."},
{"n":30,"slug":"plating-current-ratio","field":"Materials Processing","title":"Plating Uniformity Is a Current Ratio","claim":"Electroplating thickness uniformity is set by the ratio of ohmic to kinetic resistance rather than by current density.","mechanism":"When ohmic resistance dominates, current crowds at edges; when kinetics dominate, it distributes. The ratio sets which regime applies.","predictions":["Uniformity should track the ratio.","Higher current density should not fix edge build-up alone."],"refute":"Uniformity tracking current density would remove the ratio."},
]