Hand-considered hypotheses, 3201–3300

Written one at a time, from the bench outward. The subject is wood, paper and forest products — drying, adhesion, fibre bonding, moisture movement and mechanical behaviour — but the entries differ in logical form as much as in topic: some claim a bound, some an inversion, some a confound, some a quantity that cannot be identified from the measurement that reports it. The form is printed with each entry. None has been tested, and the numbers that appear are order-of-magnitude estimates, marked as such, not results.

Drying: rate, gradient and check

Misattribution of the limiting resistance
H3201. The falling-rate period of kiln drying is treated as internally limited, yet in a long board the boundary layer is refreshed mainly at the ends, so the middle of the board is still governed by a surface resistance. If that is right, a board longer than about ten thicknesses (estimate) should dry at a rate that responds to air speed even in the falling-rate period, and masking the ends should remove the response.
Hidden term in a measured coefficient
H3202. Any dif fusion coefficient extracted from an unsealed board contains a term for end-grain flow, which can exceed face flow by two orders of magnitude (estimate). The reported coefficient is then a property of the specimen's geometry as much as of the wood, and the test is the same board measured with the end grain sealed and unsealed at matched thickness.
Existence bound
H3203. There is a thickness above which no schedule can dry a board without surface checking, however slowly it is run, because the surface reaches its tensile limit before the core loses its first water. The bound is set by the ratio of tensile strength across the grain to the shrinkage coefficient, and it should appear as a thickness beyond which the check count stops falling with drying time.
Confounded measurement
H3204. The prong test for case-hardening is read as a residual stress profile, but part of each prong's deflection is the moisture gradient that cutting the prongs establishes. A specimen equilibrated at the kiln's final condition before cutting should deflect less than one cut and measured at once, and the difference is the size of the confound.
Threshold claim
H3205. Surface checking begins only above a drying rate set by the ratio of the surface layer's tensile strength to the shrinkage it must accommodate, not by the board's total shrinkage. Below that rate a strongly shrinking species should dry without checks, and a rate ladder at constant total shrinkage is the test.
Instrument artefact
H3206. Internal checks seen by X-ray attenuation may be resin and extractive accumulations, which attenuate differently from voids and can be counted as cracks. Solvent-extracted and unextracted specimens from the same board should differ in apparent check count if the artefact is present, and should agree on genuine voids.
Path dependence
H3207. Moisture content is not a state variable for wood: a board dried, rewetted and redried reaches the same average moisture with a different internal distribution and a different stress state, because pit membranes deform on first desorption. A drying schedule is therefore not invertible, and two boards at the same moisture can sit at different points of the same schedule.
Non-separability of schedule variables
H3208. Dry- bulb and wet-bulb settings do not fix a kiln's drying environment independently of the load, because the load's own evaporation raises the local humidity. Two kilns at identical set points but different surface-area-to-volume ratios should dry at different effective wet-bulb temperatures, so a schedule written in temperatures alone is under-determined.
Two-regime claim with a diagnostic
H3209. Drying time should scale with the square of thickness below fibre saturation and linearly with thickness above it, because the transition from bound-water diffusion to capillary flow changes the exponent. A log-log plot should therefore have a break, and the thickness at the break is a more direct measure of fibre saturation than the sorption isotherm.
Rate-limiting step switch
H3210. In high-temperature drying the limiting step switches from capillary flow to vapour diffusion through pit membranes at a temperature set by the pore-size distribution rather than by species. The switch should appear as a change in apparent activation energy, and its temperature should move with permeability rather than with density.
Non-monotonic response
H3211. Raising kiln temperature first shortens drying and then lengthens it, because above a threshold the surface case- hardens and the layer beneath the case loses permeability as the lumens collapse. Drying time should then show a shallow minimum against temperature, and the minimum should be absent in a species that does not collapse.
Practical floor
H3212. The energy needed to dry a board has a floor set by the latent heat of the water removed plus the heat carried out in the exhaust air, and the second term is usually the larger in a well-run kiln. Heat recovery can approach that floor but not cross it, so a claimed saving beyond it implies that less water left the board than the mass balance says.

Water in the cell wall

Identity of two coefficients
H3213. The steady-state and transient diffusion coefficients reported for bound water are the same coefficient multiplied by the slope of the sorption isotherm, so they agree only where the isotherm is linear. Where they disagree, the discrepancy measures curvature and hysteresis, not diffusivity, and a two-humidity test can separate the three.
Hidden mechanism
H3214. Sorption hysteresis is assigned to relaxation of the cell wall, but a large part of the loop may come from water held in pit chambers, whose menisci empty and fill at different potentials. Removing the pits should shrink the loop without changing the wall's chemistry, and the shrinkage measures the pit contribution.
Sign reversal
H3215. The temperature dependence of bound-water diffusion should reverse above roughly 60 °C (estimate), because thermal softening lowers tortuosity faster than it raises the activation barrier. A temperature ladder should therefore show a maximum in diffusivity, and the maximum should move to lower temperature as moisture content rises.
Mechanical bound on transport
H3216. Water cannot be drawn through a pit membrane faster than its pores allow without the meniscus cavitating, so a drying board has a maximum sustainable tension gradient set by pore radius rather than by permeability. Above that gradient the column breaks and the interior dries by vapour, which is why a high-temperature schedule helps a permeable species and not a refractory one.
Parameter count
H3217. Three parameters describe a wood sorption isotherm within its measurement noise (estimate), and models with five are fitting the hysteresis branch rather than the material. A three-parameter fit to the desorption branch, followed by a parameter-free prediction of the absorption branch, is the check.
Scale argument
H3218. The coefficient measured on a thin section is a serial average of lumen and wall paths, and it changes when the section is thinner than the tracheid length because the paths stop being in series. A thickness series should show a plateau above the fibre length and a rise below it, and only the plateau value is a material property.
Null hypothesis
H3219. The equilibrium moisture difference between heartwood and sapwood at the same humidity may be entirely a mass effect of extractives rather than a difference in sorption sites. Extracting both tissues to constant mass and re-measuring at the same humidity should erase the difference if the null holds.
Compensation claim
H3220. Species with a high fibre saturation point tend to have a low shrinkage coefficient per unit moisture, so the total dimensional change from oven-dry to fibre saturation varies less across species than either factor alone. If true, the pair is a single design parameter and quoting either factor by itself misleads.
Rate reversal
H3221. The transient strain of loaded wood under a moisture change should shrink and then reverse sign as the ramp is slowed below the cell wall's relaxation time, because slow sorption lets the wall relax the stress that fast sorption converts into strain. One specimen tested at two ramp rates through the same moisture interval is the test.
Thermal memory
H3222. The moisture content at which a board stops swelling on wetting is set by the highest temperature it has ever reached, not by its current moisture, because the hydrogen-bond network keeps the configuration it held when softened. Two boards at equal moisture with different thermal histories should swell differently, and the difference should anneal out only above the earlier maximum.
Confound of specimen size
H3223. Species differences in equilibrium moisture content are confounded with equilibration time, since a thick specimen that has not equilibrated reads low and slow-diffusing species look less hygroscopic. Two thicknesses held to constant mass should separate the material from the method.
Identifiability
H3224. One sorption isotherm cannot separate the heat of sorption from the number of accessible sites, because both bend the curve in the same direction. Isotherms at two temperatures are the minimum for that separation, and any single-temperature split into site count and binding energy is one equation short.
Definitional ambiguity
H3225. Fibre saturation is a pore size rather than a moisture content: it is the point at which the largest accessible void stops filling, so it depends on how the specimen was cut and which pits were severed. Radial and tangential samples of the same wood should give two fibre saturation points, and the gap is the definition made visible.
Self-similarity test
H3226. If bound-water diffusion is Fickian, profiles from a step change must collapse onto one curve when scaled by the square root of time, and any residual at long times is the wall's relaxation. The time at which the collapse fails is then the relaxation time, obtained without a mechanical test.

Adhesion and the glue line

Misattribution of joint strength
H3227. In a thin glue line the measured shear strength is the wood's rolling shear strength, not the adhesive's, so adhesives ranked by lap-shear tests are partly ranked by the wood beneath them. The crossover thickness, where failure moves from the bond line into the wood, should scale with the adhesive's modulus.
Hidden term from specimen geometry
H3228. Every lap- shear specimen carries a peel component from its eccentric load path, and that component changes as the wood swells, so an adhesive's apparent humidity sensitivity is partly the specimen's geometry. A symmetric double-lap specimen should show much less humidity sensitivity at the same adhesive and wood.
Threshold with a scaling law
H3229. Below a minimum glue-line thickness a joint loses strength because the adhesive cannot span the surface roughness, and the minimum scales with roughness amplitude rather than with chemistry. Joints at controlled roughness should collapse onto one curve when thickness is normalized by roughness.
Interior optimum
H3230. Penetration is usually maximized, but beyond a depth the penetrated layer stiffens the wood's surface and concentrates peel stress at the interface, so strength has an interior maximum. Strength against penetration should peak where the modulus ratio matches, and varying penetration at fixed glue-line thickness locates the peak.
Count of identifiable parameters
H3231. A wood bond has three possible failure loci — adhesive, interphase and wood — so strength data alone identify at most three interfacial parameters. A four-parameter fit to three species should leave one parameter unidentifiable, and the test is whether its interval spans the physically possible range.
Dose metric
H3232. Bond strength lost to humidity cycling follows the number of crossings of fibre saturation, not the total moisture dose or the elapsed time, because each crossing ratchets the interphase by a fixed amount. Two specimens given the same dose over different numbers of crossings should differ in strength by a predictable amount.
Two-part necessary condition
H3233. For a formaldehyde-free adhesive to match an aminoplastic bond's creep resistance it needs a glass transition above the service temperature and a secondary relaxation below it; a single high glass transition is not sufficient. The secondary relaxation is what dissipates the stress that builds when wood swells against a rigid line.
Equivalence of two tests
H3234. Wet strength and boil resistance may be one measurement at two time scales, so a joint that passes one and fails the other is reporting on the wood's extractives rather than on the adhesive. Joints from extracted and unextracted wood of one species are the test.
Boundary condition
H3235. Cure is limited by the moisture at the wood's surface, which machining sets and which can differ from the board's average by several percentage points. Joint strength should therefore depend on how long ago the surfaces were planed at constant board moisture, and that dependence should vanish if the surfaces are conditioned after planing.
Selection rule that reverses
H3236. Between two adhesives of equal dry strength, the more compliant one makes the stronger joint in thin wood because load transfer length scales with the stiffness ratio, while the stiffer one wins in thick wood. The crossover thickness is a design number, and it should move with the wood's modulus.
Bound from the adherend
H3237. No wood bond can exceed the wood's shear strength perpendicular to the grain, so above that ceiling adhesive improvement does nothing and only geometry remains. A joint that fails in the wood beyond that stress is reporting the wood, not the bond.
Non-separability of formulation variables
H3238. Cur e rate and penetration cannot be tuned independently, because the formulation that penetrates fastest also gels fastest, so open time and penetration trade along a single line in formulation space. A plot of the two for a formulation family should be a curve rather than a scatter, and its slope is a formulation constant.
Proxy saturation
H3239. The wood-failure percentage used to judge a bond saturates: once the bond exceeds the wood's strength the number reports the wood's variability, not the bond's quality. Two adhesives both above the ceiling should give the same percentage, and any difference is a sampling effect.
Reversal with pressure
H3240. Clamping pressure improves a bond up to a point and then degrades it, because above that pressure adhesive is squeezed out of the lumens that gave mechanical interlock. Pressure at peak strength should scale inversely with furnish density, so a low-density wood tolerates more pressure than a high-density one.

Fibre bonding and sheet structure

Degeneracy
H3241. Bond strength and bonded area are not separately measurable from a handsheet's tensile strength; only their product is, so a model reporting both resolves a degeneracy with an assumption. A series in which pressing changes area and a coupling agent changes strength should depend on the product alone.
Hidden contribution
H3242. The relative bonded area inferred from light scattering includes collapsed lumen surfaces, which carry no load, so the scattering estimate overstates bonding in high-yield pulps. Sheets from one furnish at two levels of collapse should differ in scattering but not in tensile, and that difference is the overstatement.
Threshold with a mechanism change
H3243. Below a fibre length the sheet fails by pull-out and above it by fibre fracture, with the transition set by bond strength per unit area rather than by fibre strength. A length series at constant bonding should show a change in slope, and the intersection is the transition length.
Symmetry redundancy
H3244. An orthotropic network needs three independent elastic measurements, not five, because symmetry fixes the rest, so data showing five independent moduli indicate bias rather than extra physics. Checking the symmetry relations on a single sheet is the direct test.
Which average
H3245. The length controlling network strength is the length-weighted mean, not the number-average, because load transfer is weighted by each fibre's cross-section. Two pulps with equal number-average length but different tails should differ in strength in proportion to their weighted means.
Survival, not formation
H3246. Bonding in a drying sheet is limited by the contacts that survive shrinkage, not by those formed when the fibres first touch, so a restrained sheet has more bonds and a different network. The two effects are confounded in any wet-strength measurement made after drying, and separating them needs two restraints at equal final moisture.
Kinematic constraint
H3247. A fibre network cannot densify in-plane without buckling out of plane, and the buckle wavelength is set by fibre length, so caliper and formation are coupled rather than independently controllable. Sheets pressed to equal caliper from furnishes of different fibre length should differ in formation by an amount set by that wavelength.
Two percolation thresholds
H3248. Conductive fibres percolate electrically at a volume fraction set by aspect ratio, but the same fibres percolate mechanically at a lower fraction because stress transfers over a longer range than charge. One sheet series should show both thresholds, and their ratio measures the transfer range.
Saturation and crossover
H3249. Beyond a refining energy the fibre wall's outer layers are removed faster than the fibre is made flexible, so tear strength peaks and falls while tensile strength keeps rising. The peak is a refining set point rather than a material constant, and it should move with the pulp's initial wall thickness.
Irreversibility of curl
H3250. The compressive behaviour of a fibre mat differs between the first loading and later ones because fibre curl is set irreversibly on first compression, so caliper depends on how often the sheet has been calendered. A sheet measured before and after one extra nip should differ at equal load, and the difference should not recover on standing.
Coupled objectives
H3251. Formation and fibre orientation are coupled through headbox turbulence, so a sheet cannot have both perfect uniformity and strong orientation; the achievable frontier is a curve, not a point. Sheets made across a turbulence range should trace that curve, whose shape is a machine constant.
Measurement artefact
H3252. Fibre wall thickness measured by confocal microscopy on a wet sheet is inflated by swelling in the mounting medium, and the inflation depends on the medium's refractive index. Dry and wet measurements of the same fibres should differ systematically, and the difference should vanish when the index matches the wall's.
Interior optimum in a blend
H3253. A blend of long and short fibres gives maximum tear at an intermediate ratio, where short fibres fill the voids between long ones at a particular packing fraction. Tear at the peak should follow the two fibres' diameter ratio rather than their length ratio, and the peak should be a maximum rather than a plateau.
Property-specific reversal
H3254. Increasing drying restraint raises tensile strength but lowers extensibility, so toughness has an interior maximum in restraint, and 'restraint is good' is a statement about one property only. A restraint series measured for all three should place the toughness maximum away from the strength maximum.
Limiting case that fails
H3255. In the limit of zero bonding a network's modulus should vanish, yet measured values extrapolate to a positive intercept, which is the fibres' own bending stiffness. The intercept should scale with the cube of fibre length and with sheet density, and it bounds how low a modulus can go at a given density.
Ambiguity requiring a second test
H3256. One network with many weak bonds and another with few strong bonds can give identical tensile and tear values, so standard tests cannot distinguish them. Cyclic loading should, because the weak-bond network loses stiffness at a lower stress.

Paper in converting and service

Rate dependence with a ceiling
H3257. Paper's strength rises with strain rate only until the rate at which moisture can no longer redistribute within the sheet; above that the measured strength is the dry sheet's and the curve flattens. The knee should move with moisture content and thickness, and its position measures the wall's diffusion time.
Regime boundary set by geometry
H3258. Creep in paper has two regimes separated by the time water takes to cross a fibre wall, so the boundary moves with wall thickness rather than with polymer chemistry. Thick- and thin-walled fibres of one chemistry should show the boundary at times proportional to the square of wall thickness.
Fracture bound
H3259. Fracture toughness of a sheet is bounded by fibre strength multiplied by the process-zone width, and that width is set by fibre length rather than by bonding. No sheet can be tougher than its fibres permit, so toughening by bonding alone must fail beyond a point.
Confound in wet strength
H3260. Wet strength is confounded with water uptake, since a sheet that absorbs less water looks stronger when wet even if its bonds are unchanged. Normalizing strength by saturated water content should collapse data from different furnishes onto one line.
Instability threshold
H3261. Wrinkling in a wound roll is a buckling instability whose onset is set by the ratio of winding tension to bending stiffness, and above a critical diameter the critical tension stops depending on diameter. The threshold should be measurable by winding one paper at several tensions and reading the onset radius.
Rate-limiting interface
H3262. Crease quality in paperboard is limited by delamination between plies rather than by compression of the surface, so a board with stronger interply bonds creases worse — an inversion of 'stronger is better'. Boards with the same surface but different interply strength are the test.
Moisture threshold for a process
H3263. Below a moisture content set by the fibre wall's softening, paper cannot be calendered to a given gloss at any pressure, because the wall must plasticize to conform to the calender's roughness. Above it gloss should rise steeply with pressure and then saturate; below it pressure should do nothing.
Redundancy count
H3264. Dimensional stability needs two numbers, a hygroexpansivity and an anisotropy ratio, and the four-directional data usually reported are redundant by orthotropic symmetry. The fourth direction should be predictable from the other three within measurement error.
Ranking reversal between scales
H3265. The ranking of two pulps by tensile strength can reverse between a handsheet and a machine-made sheet, because machine orientation amplifies the length difference in one direction while the handsheet averages it. The reversal should vanish when both sheets are tested at equal orientation ratio.
Compensation
H3266. More bonded area raises a sheet's modulus and restrains its swelling, so hygroexpansivity and modulus run inversely across furnishes and their product is nearly constant. If so, one measurement predicts the other and selection needs only one test.
Boundary that is not a material property
H3267. The moisture at which stacked sheets block is a property of the stack's pressure and dwell time rather than of the paper, so blocking results do not transfer between reels wound at different tensions. A blocking test at two winding tensions should give two thresholds for one paper.
Conservation argument
H3268. In a sheet dried under restraint the stored strain energy equals the work the restraint performed, so drying shrinkage and drying stress are two readings of one quantity and cannot be measured independently. Measuring both on one sheet should agree only if the sheet did not creep, and the disagreement is the creep.

Wood as a structural material

Misattribution of ductility
H3269. The ductility of wood in compression parallel to grain is assigned to microfibril angle, but in dry wood much of it is sequential collapse of lumens, so equal angles give unequal ductility at different densities. A density series at constant angle should separate them, and the collapse part should vanish when the lumens are filled.
Separating two size effects
H3270. Strength falls with specimen size both because larger volumes contain larger flaws and because a longer gauge length puts more of the specimen at peak stress. Testing at constant volume while varying shape separates them, and only the shape-dependent part belongs to the method rather than the material.
Symmetry reduces the count
H3271. Wood's orthotropy may be the projection of one cell-wall property onto three axes, so the nine elastic constants are not independent and one should follow from the other eight. Species spanning wide density and angle ranges are the test, and the prediction should hold within the scatter the projection allows.
Ranking inversion between load cases
H3272. Denser wood need not be stiffer in bending, because density and microfibril angle co-vary, and the species ranking by bending stiffness can differ from the ranking by tensile stiffness. The inversion should be systematic with angle and should disappear among species matched for angle.
Loop area as a moisture signature
H3273. The area of wood's load-deflection loop is usually assigned to viscoelasticity, but at constant temperature under changing humidity it is dominated by moisture redistribution within the specimen. A loop at constant moisture should be much thinner than one across a humidity cycle at the same deflection.
Threshold then power law
H3274. There is a stress below which wood does not creep measurably over decades, set by shear yielding in the cell wall, and above it the creep rate follows a power law whose exponent is a material constant. The threshold is where the log-rate against log-time curve stops being flat, and it should be independent of specimen size.
Reversal across load cases
H3275. Knots reduce tensile strength far more than compressive strength, so a board's tensile grade can rank it differently from its compressive grade, and the disagreement grows with knot size. Boards graded both ways should show their rank correlation falling as knot size rises.
Hidden term in a dynamic measurement
H3276. A vibrat ion modulus includes the specimen's shear deformation and its supports' compliance, so the apparent frequency dependence of wood's modulus is often the geometry's dispersion. The same specimen on two supports should change the apparent dispersion if it is geometric and keep it if it is material.
Non-monotonic limit case
H3277. Strength should rise as moisture falls, yet measured strength peaks at low moisture and falls again in the oven-dry state because micro-cracks open on desorption. The peak should move with drying severity, so a slowly dried specimen should peak at a lower moisture than a fast-dried one.
Bifurcation
H3278. Under sustained load wood either creeps to failure or settles, and which happens is decided by whether the load exceeds a fraction of short-term strength rather than by a distribution of lives. If the transition is sharp, a load-ratio design rule suits better than a safety factor against creep rupture.
Non-separability of two properties
H3279. Stiffness and strength are not equally predictable from density, because microfibril angle moves strength over roughly a factor of two while moving modulus by only about a third at the same density (estimate). Density grading is therefore sound for stiffness and weak for strength, and the gap belongs to the angle distribution rather than to the machine.
Energy accounting
H3280. Energy absorbed in wood fracture is dominated by friction during fibre pull-out rather than by new surface, so raising surface energy does little for toughness while raising fibre length does much. The pull-out term should scale with the square of length in a fracture test across span-to-depth ratios.
Specimen-thickness limit
H3281. The rising R-curve of wood plateaus at a crack extension set by the fibre bridging zone, and below a specimen thickness comparable to that zone the rise cannot be measured. A thickness series should show the plateau appear and then stabilize once thickness exceeds the zone.
Sign that looks like error
H3282. A Poisson's ratio above 0.5 in the radial-tangential plane need not be an error, because in compression the lumens collapse and the volume can decrease. Simultaneous lateral strain and volume measurement should show collapse exactly where the ratio passes 0.5.
Directional memory
H3283. Wood's modulus at a given moisture depends on the direction of the last moisture change, being higher after drying than after wetting, and the difference decays at the wall's relaxation rate. A specimen cycled between two humidities should show modulus hysteresis that shrinks as the cycle period lengthens.
Irreconcilable tests
H3284. Two standard shear tests disagree by a factor that depends on grain angle, and the disagreement is a difference in imposed stress state rather than experimental error, so no single shear strength exists. Strain-instrumented specimens should show different strain fields at equal nominal stress, and the difference should account for the factor.

Grading and measurement

Why a proxy works for one property only
H3285. Acous tic velocity predicts modulus well and strength poorly because velocity is dominated by earlywood stiffness while strength is governed by latewood, and the two are anti-correlated across growth conditions. Boards from fast- and slow-grown trees should show velocity tightly tied to modulus and weakly or negatively to strength.
What the instrument measures
H3286. A resistance moisture meter reads a current carried by ions rather than by water, so below about ten per cent moisture (estimate) the reading is largely an extractive measurement. Meters should read differently on two species at equal moisture but different extractive content, and washing the extractives out should move the reading.
Sampling artefact
H3287. A core sample's moisture is biased low because coring heats and dries the wood, and the bias scales with bit speed and permeability. Two laboratories coring one board at different speeds should disagree systematically, while oven-drying the whole board settles which reading is right.
Calibration transfer
H3288. A moisture-meter calibration does not transfer between species at equal density, because its slope is set by bound- water mobility, which extractives change. Two species matched for density but not extractives should need different calibrations, with the difference tracking extractive content.
Observability limit
H3289. The internal moisture profile of a board cannot be inferred from surface measurements once the diffusion time exceeds the measurement's duration, so beyond that point the profile is an assumption. Destructive profile measurement at the same instant as the surface reading would show how long the inference holds.
Method dominates material
H3290. Between-laboratory scatter in wood's modulus exceeds between-specimen scatter, so the method dominates, and its largest term is the support condition. A round robin in which every laboratory uses identical supports should cut the scatter more than any improvement in specimen preparation.
A standard that is not a bound
H3291. The small clear specimen's strength is not a lower bound for a board's strength, because the specimen removes the defects that govern the board, so the 'characteristic' value is neither characteristic nor a bound. Paired tests of small specimens and full boards from the same logs should show the board falling below the specimen as defect severity rises.
Ambiguity in a base quantity
H3292. Density of wood is ambiguous at the cell-wall level: counting or excluding the lumens changes the value by nearly a factor of two in low-density species (estimate). Every property derived from density inherits that ambiguity, and a correlation should be checked against both definitions before it is believed.

Panels, durability and closure

Trade-off with a bound
H3293. In oriented strand board, orientation improves one axis at the expense of the other, and the product of the two strengths is bounded by the strand's own strength, so orientation redistributes capacity rather than creating it. Panels across an orientation range should trace a hyperbola in the two-strength plane.
Hidden mass effect
H3294. Part of the property gain from more resin is the resin's own mass raising panel density, so at constant density the gain is smaller by a measurable factor. Panels pressed to equal density at two resin levels should differ less than panels pressed to equal thickness.
Self-limiting process
H3295. Fungal decay in a thick member is self-limited because the decay front outruns the oxygen supply, so the depth of active decay is set by oxygen diffusion rather than by natural durability. Thick and thin specimens of one species should show equal surface decay rates but different depths of active decay.
Threshold that belongs to the surface
H3296. Mould cannot germinate below a moisture content set by surface temperature and local humidity rather than by species, so 'mould-resistant' species are those that dry faster. Specimens conditioned to equal surface moisture at different temperatures should germinate at the same moisture whatever the species.
Inversion of a treatment goal
H3297. Deep preservative penetration is usually maximized, but a deeply treated shell can be worse than a shallow one because the treated zone restrains the core's swelling and concentrates stress at the boundary. Strength loss should peak at an intermediate penetration depth at constant retention.
Governed by the slowest component
H3298. A panel's long-term creep is bounded by its slowest component's creep rather than by the average, so a small mass fraction of a creep-prone adhesive can govern behaviour far out of proportion to its weight. Panels with decreasing adhesive fractions should approach the adhesive's creep until the fraction falls below a threshold.
Identity of two mechanisms
H3299. The conductivity gain from densifying a panel and the gain from wetting it are one mechanism, both replacing air with a solid or a liquid, so a dry dense panel and a wet light one can conduct equally by different routes. Crossing density and moisture should collapse onto one curve when plotted against the air fraction.
Unification claim, with a test
H3300. Every result above can be read as a competition between a transport rate and a relaxation rate, so one dimensionless group should order drying, bonding and strength data across all five subfields. The test is a collapsed plot: if one group arranges the data, the diversity of wood, paper and panels is a difference of parameters rather than of physics.

Status and plan

100 of the set. Each was written on its own and given its own logical form; the forms are labelled so that structural repetition would be visible if it crept in.

The five subfields were kept in view together, because most of the interesting claims sit where two of them meet — a drying gradient with an adhesion boundary, a fibre bond with a moisture history. None has been tested; the estimates are marked and are no better than order of magnitude.

If one of these is worth an experiment, it is H3282 — that a Poisson’s ratio above 0.5 in wood is a signature of lumen collapse rather than an error. Two strain gauges and a volume measurement on a compression specimen would settle it in an afternoon.

Incoprea Research · hand-considered hypotheses 3201–3300 · 3 November 2026 · ~/Desktop/Nov3/