Hand-considered hypotheses, 3301–3400

Textiles and fibre assemblies, written one at a time. Each entry takes one claim about a fibre, a yarn, a cloth, a dyebath, a finish, a garment's microclimate or a bonded web, and states the mechanism that would make it true together with the observation that would make it false. The logical form is printed with each, because a hundred entries sharing one argument shape would be one entry repeated. None has been tested; nothing here is cited, and any magnitude offered is an estimate to be measured rather than a number to be trusted.

The single fibre, and what a fibre test can mean

Misattribution
H3301. Bundle tenacity is read as a fibre property diluted by irregularity, yet a bundle also suppresses the lateral contraction that a free filament performs just before it breaks. If the deficit belongs to that constraint, it should scale with the number of neighbours rather than with the test length, which is exactly what an irregularity explanation does not predict. Bundles of deliberately varied count, all at one gauge length, disentangle the two explanations.
Hidden term
H3302. When a wet filament is tested, the extension recorded at break includes the compliance of the clamp, the adhesive and the water film, and only the first two are usually allowed for. The water film's contribution grows as the filament's diameter falls, so fine filaments appear more plasticized than coarse ones from the same polymer, and testing two diameters on one mount, wet and dry, sizes the term.
Identity
H3303. Fatigue and creep in a filament may be one mechanism wearing two names: slow crack growth at the same surface flaw, driven once by cycles and once by time. If that is so, a filament crept to a given extension and one cycled to the same extension should carry indistinguishable residual strength. The comparison, on filaments from a single bobbin, is the entire experiment.
Bound
H3304. No filament can be torsionally stiffer than a homogeneous rod of its own axial modulus and section, and every measured torsional rigidity exceeds that floor. The excess is the signature of a radially graded modulus, a stiffer skin over a softer core, rather than of experimental error. Filaments spun with different skin thicknesses should show the excess tracking that thickness.
Reversal
H3305. Drawing raises a fibre's modulus, but past a certain draw ratio the modulus can fall again, because the tie molecules that carry load are pulled so straight that further drawing breaks them instead of orienting them. The turnover should move with drawing temperature rather than with polymer grade. A draw-ratio series at two temperatures, with modulus and orientation measured on the same specimens, places it.
Scale argument
H3306. 'Fibre diameter' is a distribution, and every attribute computed from its mean inherits an error whose size depends on which moment of the distribution the attribute weights. Bending rigidity is the most exposed, because it weights the coarsest fibres most heavily, while specific surface weights the finest. Measuring fineness, specific surface and bending on one lot, and comparing each against the full distribution, shows which reported values are really averages.

Drafting, twisting, and the making of a yarn

Crossover
H3307. The periodic thick places in a drawn sliver are blamed on eccentric rollers, but their wavelength follows the draft ratio, which means they are a resonance of the accelerating fibre fringe and not a machine fault. Changing draft at a fixed roller setting should move the wavelength in proportion, while changing roller eccentricity should move only the amplitude. One two-factor trial distinguishes the two accounts.
Saturation
H3308. Adding air pressure in a jet-spinning nozzle stops adding wrapper fibres past a certain point, because the supply of free fibre ends at the nozzle is already exhausted. The saturation pressure is therefore set by the drafting zone's control of floating fibres, not by the nozzle's geometry. Two machines with different break drafts should saturate at different pressures, which is both a test of the claim and a way to compare their drafting zones.
Hysteresis
H3309. A core-spun yarn remembers the tension at which its core was fed, because the sheath's residual torque is set by that tension and is not erased by winding. Two yarns identical in count and twist can therefore snarl differently, and spinning one core at three tensions while measuring torque and snarl length turns the memory into a calibration.
Conservation
H3310. Migration of fibres in a staple yarn cannot happen without a compensating redistribution of packing, so a yarn with strong migration must also carry a radial density gradient. The gradient is not an independent defect but the bookkeeping of migration. Sectioning yarns of known migration amplitude and mapping packing across the section would confirm the accounting or break it.
Unit trap
H3311. The hairiness index counts protruding fibres per unit length and is blind to how far they protrude, so two yarns with equal indices can differ in the mass of fibre outside the core. A claim that a treatment reduces hairiness is therefore a claim about a count until protruding length is measured too. Both measurements on the same bobbins, before and after treatment, settle what the treatment did.
Existence of a zero
H3312. There is a ply twist at which the ply's torque cancels the torque inherited from the singles, and the resulting yarn is not merely balanced but torque-free in the hand. Its existence follows from the two torques having opposite signs and different dependences on twist. A torque sweep across ply twist must cross zero, and the crossing is the design point rather than a curiosity.
Optimum
H3313. Friction-spun yarn strength rises and then falls with drum speed, because faster drums wrap more fibres while each wrapper grips less. The optimum therefore belongs to the fibre's finish rather than to the machine. Two finishes of different friction should place the optimum at different speeds, a prediction one machine can test in a day.
Proxy
H3314. The life of a ring traveller is a proxy for the durability of the fibre finish, since the traveller wears against the finish rather than against the fibre itself. That makes a component normally treated as consumable into a cheap tribometer. Running one finish at several add-ons and reading traveller life calibrates the proxy against a laboratory friction rig.
Plateau
H3315. The fibre ring in a rotor groove is self-limiting: centrifugal compaction adds fibre while peeling removes it, and the two balance at a mass that stops responding to feed rate. This is why rotor yarns produced at very different rates can have similar structure, and a feed-rate series should reveal the plateau if the balance is real.
Two-name collapse
H3316. What is called twist loss in the doffing tube and false twist in the transport channel may be a single event, the ribbon's torque relaxation, observed at two places. If so, one relaxation time measured on the ribbon alone should predict both. A tube-length series at fixed rotor speed tests whether a single time constant fits.
Necessity
H3317. Pneumatic compaction cannot reduce hairiness without changing the yarn's packing, because the same air current that wraps protruding fibres also pulls the ribbon together. Any report of lower hairiness at unchanged packing therefore describes either a different mechanism or a measurement of the wrong surface. Measuring packing and hairiness together across a compaction series separates the possibilities.
Inversion of standard practice
H3318. Worsted combing is designed to remove short fibres on the theory that they weaken yarns, but short fibres also fill interstices and raise packing, so removing them can cost abrasion resistance while gaining tenacity. Combing intensity should therefore be set by the intended wear mode rather than by the fibre-length distribution. A combing series tested for both tenacity and abrasion would locate the crossover.
Non-transferability
H3319. A yarn's irregularity measured on a laboratory frame does not transfer to a mill frame, because the laboratory runs slower and the drafting force's dynamic component is smaller, and the irregularity follows that force rather than the draft alone. The transferable quantity is the force trace, not the coefficient of variation. Recording force traces on both frames and matching them would test the claim and give the mill a calibration route.
Suppression
H3320. Fibre breakage in drafting is studied at the roller nip, but the break may occur earlier, where the trailing end is accelerated out of the fringe, which would make nip-based diagnostics blind to it. High-speed imaging of the fringe with the nip out of frame shows whether breaks precede the nip. If they do, every draft-zone model calibrated on nip force is calibrated on the wrong event.
Count
H3321. A two-component blend yarn has at most two independent radial concentration profiles, one per component, so a reported third blend structure is a re-description of those two. The test is whether a three-parameter fit beats a two-parameter fit on measured radial profiles, and until that comparison is made for a given system the third structure remains an assertion.
Equifinality
H3322. Two spinning routes can yield yarns of identical count, twist and tenacity that behave differently in weaving, because the difference lives in the distribution of fibre ends rather than in any measured mean. If so, an end-distribution metric should predict weavability while the standard means do not. Measuring end distributions on both yarns and following them through the loom is the test.
Independence claim
H3323. Hairiness and irregularity are usually treated as two readings of one underlying unevenness, but a yarn can be hairy without being irregular, since the two are produced in different zones of the machine. Their independence is the useful fact, because it lets a mill fix one without disturbing the other. A designed trial on draft and twist, with both responses measured, shows whether the independence survives.
Reframing
H3324. The spinning triangle is drawn as a triangle, but a fibre under tension between the nip and the yarn hangs in a catenary, so tension across the ribbon is not linear in position. Predictions that assume a triangular profile are therefore biased at the edges, where the curvature is greatest. Recomputing the profile as a catenary changes the predicted edge tension without changing any measured input, which is what a reframing should do.

Shed, pick, and the building of cloth

Constrained optimum
H3325. Reed denting is normally chosen to space ends evenly, but uneven denting can be optimal when the warp's yarns differ in abrasion resistance, because it places the weaker yarns where they rub against fewer neighbours. Optimality here is a statement about the weave's failure mode, not about appearance. Weaving one warp with even and deliberately uneven denting, and recording which yarns break first, would show whether failure follows the denting.
Instrument re-purposed
H3326. The peak beat-up force is read as a loom setting, yet it is really the fabric's incremental modulus at the fell, sampled once per pick. That makes the loom's force transducer a fabric- mechanics instrument already installed in every weave room. Weaving a pick-density series on one warp, and comparing the force peaks with off-loom modulus, calibrates it.
Boundary effect
H3327. A tight selvage is usually explained by differential take-up, but the edge yarns also have fewer interlacing points per unit length, so they crimp more and the edge buckles in its own plane. The selvage wave is then a buckling pattern whose wavelength is set by the edge's bending stiffness rather than by tension. Weaving several edge constructions at identical tension tests the distinction.
Sensor aliasing
H3328. The weft arrival sensor times the leading end, but the pick's mass is unevenly distributed, so the arrival time reports the heaviest section rather than the pick as programmed. A control loop fed by that signal can therefore hold a fabric steady while a periodic thick place travels through it, and only a full-length weft profile, pick by pick, reveals the difference.
Definitional
H3329. Cover factor assumes circular yarns in a square array, which makes it a definition rather than a geometric measurement: two fabrics can share a cover factor and differ in open area. Calendering flattens the yarns and changes the open area without changing the cover factor at all. Image analysis of one fabric before and after calendering shows the divergence directly.
Coupled constraint
H3330. Pile height in terry weaving is credited to the pile-warp let-off and the beat-up, but the ground warp's tension also sets it, because the loops form against the ground's resistance. Three controls with only two degrees of freedom leave a machine less adjustable than its manual suggests. A three-factor weave trial with pile height measured optically maps the real constraint surface.
Moiré
H3331. Reed marks are a moiré between the dent pitch and the weave repeat, so their spacing is set by the pair and not by either alone. The same reed should therefore mark at one pick density and not at another. Weaving a pick-density series with a single reed, and locating the densities that mark, tests the arithmetic.
Selection effect
H3332. Ends-down rates are attributed to yarn strength because only broken ends are counted, while the ends that were abraded and survived are never examined. The rate is thus a count of the few weakest ends, not a property of the average warp. Instrumenting a warp section for abrasion loss before breakage, and correlating loss with break order, would show whether break order follows abrasion rather than strength.
Distribution claim
H3333. Size add-on is measured by weight, but abrasion resistance is set by where the size sits, and a skin-biased size protects a yarn with less add-on than a uniformly penetrated one. Two yarns of equal add-on can therefore differ several-fold in abrasion life, an estimate that must be measured for each size rather than assumed, and sectioning sized yarns to map the size radially, then abrading them, would show whether placement predicts life better than weight.
Asymmetry
H3334. Relaxation shrinkage of a woven fabric is anisotropic, and the anisotropy cannot come from releasing bending stresses alone, since those are symmetric in a balanced weave. It points instead to torsional stresses in warp and weft, which are unequal because the two yarns were spun at different twists. A weave series with matched and mismatched twist directions should show the asymmetry changing sign.
Threshold
H3335. Warp yarns flatten against the reed and the fell until the section can flatten no further, and past that point added tension only extends them. The saturation tension belongs to the yarn's structure rather than to the loom, which is why some warps weave well at tensions that break others. Measuring flattening optically across a tension series locates the knee.
Two-test contradiction
H3336. Crimp measured by the standard's straightening tension and crimp inferred from the difference between loomstate and finished length disagree systematically, because the standard defines crimp at a tension the fabric never sees in service. The two numbers are not two estimates of one quantity but measurements of two different things. Reporting both, with the tension at which they agree, would make the definition visible.

Cloth as a structure: shear, bending, drape

Friction-dominated elasticity
H3337. The initial shear modulus of a woven fabric is reported as an elastic constant, but at small angles the yarns have not begun to slide and the measured stiffness is the friction at their crossings. The number therefore changes with humidity and with finish, which an elastic constant would not. Measuring one fabric at several humidities, with the structure untouched, shows the friction signature.
Bound
H3338. The bending rigidity of a woven fabric has a floor set by the free bending of its interlaced yarns, and every measured value sits above it. The gap is the friction moment at the crossings, which the weave can change without changing the yarns. A series of weaves from one yarn with different float lengths should show the gap growing with the number of crossings per unit area.
Wavelength argument
H3339. The wavelength of a wrinkle is set by the balance of bending and membrane stiffness, yet observed wavelengths are often longer than that balance predicts. The missing compliance is crimp interchange, which lets the cloth accommodate in-plane compression without stretching. Measuring wavelength and in-plane stiffness on the same specimens, across a weave series, tests whether the crimp term closes the gap.
Disguised mechanism
H3340. Bagging recovery is reported as an elastic property, but the loops that deform during bagging are loaded at their apices, where the fibre is already near its yield strain, so recovery is a fatigue measurement in disguise. Repeated bagging at one load should therefore degrade recovery cycle by cycle even though no single cycle is excessive. Following recovery against cycle count on one specimen decides it.
Proxy
H3341. Tongue-tear strength is governed by how far yarns can slide before they break, and that distance is set by the weave's float length, so the tear test is effectively a measurement of weave geometry. This is why tear strength tracks weave more closely than fibre tenacity. Tearing a series of weaves made from one yarn separates the geometric from the material contribution.
Test-length dependence
H3342. Seam slippage depends on the clamped length in the standard test, because the yarns' crimp redistributes over whatever length the clamps leave free. A fabric can pass at one clamp length and fail at another, which makes the reported value a property of the test; running one fabric at three clamp lengths, and plotting slippage against length, shows whether it converges.
Structural, not material
H3343. Burst strength is not a material property of a woven fabric, because the specimen domes during the test and the dome's curvature depends on the fabric's own shear stiffness, so the stress state differs from fabric to fabric. The test measures formability as much as strength, which bursting one fabric through two orifice diameters would expose.
Hidden variable
H3344. Fabric thickness is quoted at a standard pressure and a standard dwell, but the compressional response is viscoelastic and the thickness is still falling when the gauge is read. The quoted number is therefore a reading of the dwell time, and measuring thickness against dwell time, extrapolating to the asymptote, yields a value that does not depend on the standard.
Insufficient specification
H3345. Air permeability is dominated by the widest channels through a fabric, so two cloths of equal porosity can differ greatly in permeability when their pore-width spreads differ, a factor that must be measured rather than assumed. Porosity alone is therefore an insufficient specification for a ventile or a filter. Measuring permeability and pore-width distribution on the same setts, across a series, shows whether the spread term is needed.
Unit trap
H3346. The drape coefficient is a single number, but drape is a shape with a node count, and two fabrics can share a coefficient while hanging with three nodes and five. The coefficient is an average that discards the feature a designer actually sees. Counting nodes alongside the coefficient on a bending-stiffness series shows whether the two numbers carry different information.
Trade-off
H3347. Softness and wrinkle recovery pull against each other because both are set by inter-fibre friction: low friction gives a soft hand and lets the cloth crease, high friction resists creasing and feels harsh. The trade-off is one-dimensional only if friction is the sole lever, which a series of softener add-ons measured for both properties can test: either the points collapse onto one curve or a second lever appears.
Non-reciprocity
H3348. Pulling a fabric along warp and along weft gives different moduli, which sett explains, but the lateral contraction under warp tension is not the transpose of the weft's, and geometry cannot explain that asymmetry. It points to a directional difference in the yarns' own lateral compressibility. Measuring both cross-terms on a balanced weave isolates the effect.
Emergence
H3349. Fabric hand is treated as an aggregate of fibre properties, but the compression and shear a hand panel actually senses are set by the network of crossings, which has no fibre-level analogue. A cloth of soft fibres in a tight weave can feel harsher than one of stiff fibres in an open weave. Holding the fibre constant and varying only the weave separates the levels.
Multiple minima
H3350. A draped fabric settles into one of several energy minima, so a specimen placed gently and one dropped can take different shapes and both be correct. Single-shape drape measurement is therefore a sampling of one basin. Releasing the same specimen from several initial configurations, and counting the distinct shapes it reaches, characterises the landscape instead of a point in it.

Dyeing, colour, and the bath

Phase error
H3351. Dye migration is treated as a levelling mechanism inside the bath, but most of the visible migration happens after the bath, as water moves to the drying surface and carries dye with it. The migration index is thus a drying-rate measurement wearing a dyeing label. Drying the same package at two rates, with identical bath history, separates the stages.
Hidden variable
H3352. The pH inside a swollen fibre is not the bath's pH, because the fibre's fixed charges impose a Donnan partition, so the acidity that governs dye ionisation is an internal quantity nobody measures directly. This makes the acid-dyeing pH effect partly a statement about the fibre's charge density, and estimating internal pH from a probe dye's partition, across a salt series, exposes the offset.
Confounded ranking
H3353. Reactive dyes are ranked by reactivity from fixation efficiency, but fixation also depends on how quickly the dye reaches the reactive sites, so a slow dye of high reactivity can rank below a fast dye of low reactivity. The table ranks a product, not a reactivity. Measuring diffusion coefficients independently, on the same substrate, would reorder it.
Negative claim
H3354. A union shade on a polyester-cellulosic blend is impossible for some colour pairs, not because the dyes are badly chosen but because the two components' accessible gamuts do not overlap where the shade requires. The boundary of the achievable region belongs to the dye classes, not to the dyer's skill. Mapping each component's gamut separately and overlaying them locates the impossible region.
Unit trap
H3355. Kubelka-Munk K/S is computed from reflectance as though the dye were uniformly distributed, so a ring-dyed fabric and a uniformly dyed one at the same average uptake can give the same K/S and look different. The quantity is a function of the distribution as much as of the concentration. Cross-sectioning both and comparing section colour tests how much distribution matters.
Threshold
H3356. Below a certain reductant concentration, reduction of a vat dye is limited by the pigment's particle size, because the reaction occurs at the particle surface and finer particles offer more of it. Above that concentration the rate stops responding to the agent, which is why more reductant stops helping; a particle-size series at fixed reductant concentration locates the transition.
Split claim
H3357. The salt effect in direct dyeing is described as one phenomenon but is two: screening of the fibre's charge, which raises uptake, and suppression of dye aggregation, which lowers the dye's activity. The two have opposite signs and different concentration dependences, so the net curve need not be monotonic. Measuring aggregation independently across the same salt series splits them.
Path dependence
H3358. Package density is set by winding and the flow distribution by the radial density gradient, so a package wound dense at the core cannot be levelled by reversing the flow, since reversal changes direction and not the gradient. Levelness is a property of the winding. Dyeing two packages with opposite gradients under one flow programme would settle the question.
Scale argument
H3359. Beam dyeing passes liquor axially, so the pressure drop grows with the beam's length and levelness along the beam becomes a pressure-drop problem rather than a chemistry problem. A long beam should be less level than a short one at equal flow per unit mass. Dyeing beams of two lengths with all chemistry fixed measures the axial gradient directly.
Spectrum, not point
H3360. A colour match approved under one illuminant is a statement about that illuminant, not about the dyes, since two recipes can share tristimulus values under one source and diverge under another. Approval therefore certifies a point where two spectra cross rather than the spectra themselves. Measuring both reflectance curves and predicting the mismatch under a second source turns approval into a spectral claim.
Constant is a variable
H3361. Exhaustion curves are fitted with a saturation value read as the fibre's dye capacity, but the capacity itself changes during dyeing as the fibre swells and the dye aggregates inside it. The fitted constant is therefore a function of the bath's trajectory, and two baths reaching the same final concentration by different routes, compared for uptake, test whether the capacity is path-dependent.
Irreversibility
H3362. Ring dyeing is described as a fault, yet the gradient it creates is what gives indigo denim its abrasion response, so the fault is the design variable. The gradient's steepness is set by the ratio of diffusion time to dyeing time, which makes it controllable. Colour loss against abrasion cycles, for two deliberately different gradients, shows whether steepness is the lever.

Finishing, and what a finish actually does

Transient setting
H3363. Calendering improves hand by flattening yarns, but the nip also lifts the fibre's surface above its glass transition for an instant, so part of the effect is a transient set rather than a permanent flattening. A cold nip at the same pressure should give a different hand if that is true. Running one fabric through hot and cold nips at matched pressure tells them apart.
Boundary effect
H3364. Mercerisation is applied uniformly, but the tension that prevents shrinkage is carried mainly by the selvages, so the middle of the cloth is treated under different tension from the edges. The result is a cross-direction gradient in lustre and dye uptake that belongs to the machine's geometry rather than to the chemistry. Mapping uptake across the width, with and without edge control, would make the gradient visible.
Hidden constraint
H3365. Compressive shrinkage is sold as setting a fabric's residual shrinkage, but the achievable set is bounded by the weave's crimp interchange, so an open weave cannot be set as far as a tight one. The process specification is therefore a property of the cloth it is applied to, and shrinking a weave series under one machine setting, plotting residual shrinkage against tightness, locates the bound.
Diffusion-limited
H3366. Formaldehyde release from a resin-finished fabric is limited by cure completeness, and cure completeness is limited by how fast the catalyst reaches the yarn's core, so a cloth can be cured at the surface and undercured within. The release test then measures the surface rather than the finish. Sectioning a cured fabric and measuring release from successive layers tests the gradient.
Split claim
H3367. Softeners are called surface lubricants, but their largest effect on hand may be on friction between fibres inside the yarn, which changes the cloth's shear rather than its surface. The two are separable, since a surface lubricant acts at the face and an internal one acts at the crossings. Applying one softener at two penetration depths, and measuring shear and surface friction separately, distinguishes them.
Coupled system
H3368. Flame retardancy is specified by add-on, but the char that protects a fabric forms in a layer whose thickness depends on how the weave conducts heat away, so two cloths at equal add-on can perform differently. The weave is part of the flame-retardant system rather than a neutral carrier. Burning a weave series at fixed add-on, and measuring char depth, tests whether the weave enters through heat transfer.
Non-proportionality
H3369. Bio-polishing removes weight from the fibre surface, but weight loss is not proportional to smoothing, because the enzyme attacks accessible regions first and those are also the regions that cause pilling. A small loss can therefore produce most of the smoothing, and measuring surface friction and weight loss together across a dose series shows whether the relation is proportional or saturating.
History dependence
H3370. Heat setting is specified by temperature, but the set achieved depends on the fibre's orientation, which was fixed by the spin-draw history, so two yarns of one polymer can set at different temperatures. The setting temperature is a property of the fibre's history rather than of the polymer. Setting yarns from two draw ratios across a temperature series, and measuring residual shrinkage, would show whether the history survives setting.
Condition dependence
H3371. The critical moisture content at which drying changes from constant-rate to falling-rate is treated as a fabric property, but it is the content at which the surface stops being fed by liquid from the interior, which depends on the air's velocity and humidity. One fabric therefore has different critical contents in different dryers; measuring the same cloth at two air velocities shows the dependence.
Recovery
H3372. Stentering a cloth wider than its woven width stores elastic energy in the crimp, and the width returns in water, which is why some stable fabrics shrink after the first wash. The stable width is the one at which crimp interchange is at equilibrium, not the one at which the cloth looks flat. Stentering to three widths and measuring recovery after a standard wash locates that width.

Comfort: heat, vapour, and the microclimate

Instrument term
H3373. The cup method's vapour resistance includes the air gap between cloth and water, and that gap's resistance is comparable to the cloth's own, so the reported fabric resistance is partly a property of the cup. Laboratories with different gaps will report different fabrics. Measuring one fabric at three gaps, and extrapolating to zero, yields the cloth's own resistance.
Compressibility
H3374. Thermal insulation is quoted as a clo value at a standard thickness, but the thickness that matters is the one under the garment's own weight and the wearer's movement, which compresses the cloth. A fabric that is thick when free can be thinner than a competitor when worn. Measuring clo at several compressive loads, and reporting the load, makes the comparison meaningful.
Hysteresis
H3375. Moisture buffering is calculated from the sorption isotherm's slope, but the isotherm has hysteresis, so buffering depends on whether the fabric is absorbing or desorbing, which depends on the wearer's history. Two fabrics with identical isotherms can buffer differently in use, and measuring buffering on the two branches separately sizes the effect.
Transient
H3376. The sensation of coolness at first contact is a transient heat flux set by the fabric's thermal effusivity, not by its steady conductivity, so a cloth can feel cool and still insulate well. Effusivity rises with moisture content, which is why a slightly damp fabric feels colder at the same temperature. Measuring effusivity at several moisture regains, on one fabric, gives the size of the shift.
Nonlinearity
H3377. Evaporative cooling from a fabric is not linear in sweat rate, because the cloth's vapour resistance changes as its water content rises and the conducting paths through it change character. A small increase in sweat rate can therefore cool more or cool less, depending on which side of the change the wearer sits. Measuring cooling against sweat rate on one fabric maps the non-monotonicity.
Regime mismatch
H3378. The standard air-permeability test uses a pressure difference far above the one a garment sees, and the flow divides among the fabric's channels differently at the two levels, so the standard number is not the in-use number. A cloth with a few wide channels can pass the standard and still feel airless. Measuring permeability at body-scale pressure differences, on fabrics with different pore-width spreads, would show how far the standard number departs from use.
Fluctuation
H3379. Microclimate humidity fluctuates with each breath and each movement, and comfort may depend more on damping those fluctuations than on their mean. A fabric with a higher mean humidity but a smaller amplitude can feel drier than one with a lower mean and a large amplitude. Measuring the humidity trace under a breathing simulator, rather than its average, would decide between the two views.
Wrong variable
H3380. The warmth of a garment in wind is credited to its thickness, but wind penetrates according to the fabric's air permeability, so a thin tight cloth can be warmer than a thick open one. Which of the two dominates is an empirical question that a set chosen to decorrelate them can answer, and heat loss measured in wind on such a set settles it.
Red herring
H3381. Fibre thermal conductivity is quoted as though it governed a fabric's warmth, but the air in the cloth carries most of the heat, so the fibre's conductivity enters only weakly. The search for low-conductivity fibres is therefore a poor route to warm fabrics. Comparing cloths of equal porosity made from fibres of very different conductivity, and measuring heat loss, shows how weak the dependence is.
Coupled transport
H3382. Vapour transmission is measured on a dry fabric, but in use the cloth contains liquid water, which changes both the vapour path and the heat path, so the dry measurement is the wrong boundary condition. A fabric can be excellent dry and poor wet. Measuring transmission at several internal water contents, on one cloth, gives the in-use curve.

Nonwovens: webs, bonds, and pores

Blurred input
H3383. Spunbond uniformity is attributed to the spinneret's hole pattern, but the filaments are still fluid when they enter the quench, so the pattern is blurred by the air's asymmetry before the web lands. A perfectly drilled spinneret can therefore produce a non-uniform web. Measuring basis-weight uniformity from one spinneret under two quench symmetries would show which account holds.
Wrong specification
H3384. Meltblown fibre diameter is specified by its mean, but capture of fine particles is governed by the fibres comparable in size to the particles, so two webs with equal means can differ in efficiency. The mean is the wrong specification for a filter, and measuring the full diameter distribution alongside efficiency on the same webs tests whether the small fibres predict better.
Energy distribution
H3385. Hydroentangling energy is delivered through the web's thickness, but the web's permeability decides how much of each jet's energy reaches the lower layers, so a denser web is bonded at the top and loose at the bottom at the same jet pressure. The depth profile of energy, not its total, is the controlling variable. Peeling successive layers and testing their strength, on webs of two permeabilities, would expose the profile.
Two-variable
H3386. Needlepunch strength is set by the number of fibres a barb catches, and that number depends on the barb's geometry as well as the web's density, so punch density alone cannot specify a web. Two lines at equal punch density but different barb shapes produce different fabrics, and a barb- geometry series at fixed punch density would show how much of the strength belongs to the barb.
Geometry of contact
H3387. Thermal bonding is specified by calendar temperature, but bonds form where the pattern's raised points touch the web, so the effective temperature depends on the pattern's contact-area fraction and a fine pattern needs more heat for the same bond. The specification belongs to the pattern. Bonding two patterns at one temperature, and measuring bond strength, would reveal the offset.
Settling scale
H3388. Airlaid uniformity is attributed to fibre properties, but the fibres settle from a turbulent stream whose eddy size is set by the forming head, so the head's scale, not the fibre's, sets the wavelength of basis-weight variation. Changing fibre without changing the head should leave that wavelength alone, which basis-weight spectra from one head with two fibres would confirm.
Aspect ratio
H3389. Wetlaid formation depends on the fibres staying dispersed until the water is removed, and dispersion stability is set by the fibre's aspect ratio rather than by the surfactant dose above a threshold. Long fibres entangle and flocculate whatever the chemistry. Forming handsheets from a length series at fixed chemistry, and measuring floc size, locates the limit.
Split claim
H3390. Beads in electrospun webs are blamed on insufficient viscosity, but they can also arise when the jet's charge is too low to suppress the instability that breaks it into droplets, and both causes look the same. They separate because conductivity changes the second and viscosity the first. Spinning a two-factor grid of the two, and counting beads, resolves the attribution.
Tortuosity
H3391. Filtration efficiency is predicted from pore size, but particles are captured by fibres, and fibre orientation decides how often a particle meets one, so two webs of equal pore size can differ in efficiency. Tortuosity rather than pore size may be the controlling geometry, which efficiency and fibre-orientation measurements on the same webs would decide.
Depth gradient
H3392. Needlepunched felts carry a fibre orientation that varies through the thickness, because barbed needles drag fibres downward and leave the surface layers more random, so the felt is not homogeneous. Its compression recovery is then a property of the through-thickness gradient rather than of the mean. Measuring recovery on felts needled from one side and from both sides isolates the gradient's contribution.

Measurement, specification, and the logic of the field

Gauge-length dependence
H3393. A textile test's gauge is chosen by convention, but every property it measures has a characteristic length (crimp period, float length, pore spacing), and when the gauge approaches that length the result depends on the gauge. Two laboratories with different clamps can then disagree while both are right. Measuring one fabric across a gauge series, and finding the plateau where the value stops moving, defines the minimum gauge.
Proxy
H3394. A hand panel's ranking is treated as a measure of surface softness, but what the fingers deform is the cloth's bending and compression, so the panel is a bending instrument with a verbal output. This is why panel scores track bending modulus better than surface friction. Asking one panel to rank fabrics chosen to decorrelate bending from surface friction shows which they are reading.
Spectrum
H3395. Yarn irregularity is specified by its coefficient of variation, but fabric appearance is governed by the low-frequency part of the irregularity spectrum, which the coefficient averages away. Two yarns with equal variation can weave into cloths of visibly different appearance, so spectra and woven appearance should be compared on one warp.
Category error
H3396. Loom efficiency is reported as a machine attribute, but the dominant cause of ends-down is warp abrasion, and abrasion resistance is set by the size's penetration, so the figure is really a sizing measurement taken in the weave room. Reading it as a machine rating misplaces the credit. Running one size at several add-ons, and reading efficiency, calibrates the proxy.
Metric boundary
H3397. A fabric's water footprint is reported as water withdrawn per kilogram, but the environmental effect is set by the water returned and its quality, so a process with high withdrawal and full recycling can score worse than one with low withdrawal and poor effluent. The metric measures the wrong end of the pipe, and computing both withdrawal and effluent load for two dyehouses, ranking them, shows whether the metric inverts the true order.
Variable omitted
H3398. Blended-fabric recyclability is treated as a chemistry problem, but mechanical separation of the components depends on fibre length and entanglement, so two blends of identical chemistry can be differently recyclable. Length is the variable that chemistry-based metrics omit, and carding one blend from two fibre lengths while measuring the purity of the separated streams would show how much it matters.
Rate selection
H3399. Tensile tests at two strain rates disagree on the same fabric, and the disagreement is usually settled by declaring one rate standard rather than by asking which rate the cloth meets in use. Since the rates in a garment are set by body motion, neither standard rate may be the relevant one; mapping a rate series and locating the in-use rate on it resolves the disagreement properly.
Unification
H3400. Three quantities measured by different industries (yarn irregularity, fabric drape and nonwoven pore size) may all be set by one length, the mean distance a fibre travels between contacts. If so, one measurement of contact spacing on an assembly should predict all three, and the test is a set of assemblies spanning the three industries, measured for spacing and for each property, checking whether one scaling collapses them.

Status and plan

One hundred entries, numbered in sequence. The subject was chosen before the argument form, so that the variety of shape is visible and auditable rather than decorative: a bound is not a misattribution, a count is not an inversion, and a claim that two named effects are one is not a claim that one named effect is two.

The physics is deliberately the physics of assemblies: the drawing of a sliver, the travel of twist, the geometry of a shed, the friction at a crossing, the diffusion of a dye into a swollen polymer, the transport of heat and vapour through a porous sheet, and the statistics of a bonded web. Nothing here is a claim about fashion, labour or markets, and no entry depends on a number taken from a source.

If one of these is worth an afternoon, it is H3310: that fibre migration in a staple yarn cannot occur without a compensating radial packing gradient, so a single section through a yarn can tell you how much migration it has. It needs a microtome and a microscope, and it would either turn migration into a cheap measurement or break a tidy piece of bookkeeping.

Incoprea Research · hand-considered hypotheses 3301–3400 · 3 November 2026 · ~/Desktop/Nov3/