A Simple and Economical Device to Process Ti Cylinders with Elongated Porosity by Freeze-Casting Techniques: Design and Manufacturing
Bibliographic record
Abstract
Nowadays, the development of materials with gradient porosity is an important aim for many applications, especially in the field of bone tissue replacement. This research work shows the design and manufacture of a simple and economical device to process Ti cylinders with elongated and high interconnected porosity by freeze-casting techniques. The influence of the vessel material on the internal lamellar structure of the porous Ti samples is also studied. The device has been validated with: (i) a thermal gradient from-10 °C at the cold surface to 20 °C at the hot surface; and (ii) a cylindrical vessel with 12 mm diameter of alumina or Teflon. These working conditions have allowed maintaining the freezing conditions during the full process (alumina vessel: 30 minutes; Teflon vessel: 3 hours). After the solidification of the Ti aqueous suspension, the ice is sublimated (24 hours at-50 °C and 0.070 mbar). Then, the resulting powder is sintered (1150 °C for 5 h at high vacuum ~ 10-5 mbar), obtaining the porous Ti sample with the final structural strength. Finally, a detailed study of the most relevant porosity features is performed: porosity ratio and interconnectivity degree by Archimedes’ method, and size and shape of the pores by image analysis at three different zones along the longitudinal cross section. The results indicate the viability of the device to enhance the directional freezing and thus, the elongated porosity. Teflon vessel present the best results, with an average porosity ratio and porosity size of 39.5 % and 123.3 μm, respectively. This suggests an optimal biomechanical and bifunctional balance of this porous material.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".