Hydrodynamic interaction within canonical macromolecular structures
Bibliographic record
Abstract
In general rigid bead-rod theory, we deduce the rheological properties of a suspension of macromolecules from the orientation distribution that arises during flow. The most important feature governing this orientation is macromolecular architecture, and right behind this, enters hydrodynamic interaction. Until now, general rigid bead-rod theory has neglected hydrodynamic interactions, namely, the interferences of Stokes flow velocity profiles between nearby beads. The lopsidedness of the architecture affects orientability, and so do these heretofore unexplored interferences within the macromolecule. We here employ a new method for exploring how such hydrodynamic interactions affect the complex viscosity. This method has, with great effort, been used to examine hydrodynamic interactions in complex architectures, namely, multi-bead rods and backbone-branched polymers. However, it has yet to be applied to canonical forms. In this paper, we focus on the simplest of rigid architectures: (i) rigid dumbbell, (ii) tridumbbell, (iii) rigid rings, and (iv) planar stars. We call these forms canonical. We arrive at beautiful algebraic expressions for the complex viscosity for each canonical form. We find that for the dimensionless complex viscosity, for all canonical forms, hydrodynamic interactions just depend on the ratio of the bead diameter to the nearest bead separation, d/2L≡A. Furthermore, we find that for the dimensionless complex viscosity, for canonical forms (i) and (iii), hydrodynamic interactions shift the real part upward and minus the imaginary part downward. For canonical forms (ii), both parts are unaffected. For canonical forms (iv), the story depends interestingly on the number of beads. We advance the mathematics of fluids by establishing, for intramolecular hydrodynamic interactions, the foundational equations which future work must recover.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".