This paper proposes a modified algorithm that predicts filament usage in human manikin three-dimensional (3D) printing. In 3D printing, the use of support structures owing to overhangs leads to an increased printing time, filament length, and final surface ruggedness, which can be minimized by selection correct choice regarding object printing orientation. To predict the amount of filament needed in 3D printing, we use the shadow-projection idea employed in previous works. We modify the original idea so that triangles are classified into alpha and beta groups with respect to their normal vector. Then, the groups are converted into alpha and beta voxels, respectively. Finally, the voxels that lie highest in the Z-direction are copied to top-covering voxels. In this way, the final volume of the filament can be easily calculated using simple linear algebra. For ease of modeling, we assumed that the internal volume and the support structure were 100% filled. The proposed algorithm is applied to the famous Stanford Bunny data and some manikin parts.

Large objects, such as human-shaped manikins, need to be segmented for three-dimensional (3D) printing, and then glued. This paper presents quantitative and experimental results on filament dimension changes to show whether segmented parts can be combined using location-fit or magnets. Two kinds of filaments, poly lactic acid (PLA) and thermoplastic polyurethan (TPU), are used in the 3D printing of two types of test structures, a hole/shaft structure and a magnet-in-hole structure. Both horizontal and vertical filament dimension changes are measured. It was found that the hole sizes should be expanded to reflect the expansion of the wall thickness in the horizontal direction. In the vertical direction, the stacking of filament layers slightly reduced the total height. In particular, we derive an equation that can explain why the minimal thickness from slicing software g-code generation varied depending on the object inclination angle. Finally, the equation results are compared with those of slicing software.

Halogen or organophosphorus-based flame retardants have been used as conventional flame retardants for textile fibers. While halogen-based flame retardants emit toxic gases such as HBr and HCl, some commercial phosphorus-based flame retardants may release large amounts of formaldehyde. In this study, as a new ecofriendly organophosphorus flame retardant, vinyl bisphosphonic acid (VBPA) is synthesized from 1-Hydroxyethane-1,1-diphosphonic acid (HEDP) with a yield of 90.8% by a high-temperature dehydration reaction at 200 ℃ for 1.5 h, which was confirmed by ³¹P nuclear magnetic resonance (NMR) as well as Fourier transform infrared (FT-IR) and Raman analyses. In addition, the thermal behavior of the VBPA-treated cotton fabrics are investigated using limiting oxygen index (LOI), thermogravimetric analysis (TGA), and microcombustion calorimetry (MCC). Lowered thermal decomposition and combustion reactions may be resulted from the dehydration and crosslinking activated by the phosphonic acids in the VBPA-cured cotton, indicating a condensed-phase flame-retarding mechanism. VBPA can be used as a new formaldehyde-free flame retardant for cellulosic fabrics.

The development of bio-plastics (i.e., biodegradable and bio-based plastics) is an important way of reducing fossil-based plastic waste. However, the degradable properties that make bio-plastic useful also provide it with significant resistance to commercial use, especially with respect to catastrophic mechanical failure in response to external stimulus. This study develops a functional biodegradable film with bi-layers (PBFs) to achieve both biodegradable features and mechanical stability by incorporating self-healable microcapsules. To improve the scratch-resistance, microcapsules comprised of a poly urea-formaldehyde (PUF) shell and a linseed oil (LO) core are infiltrated to the protective poly dimethylsiloxane (PDMS) layer. When external pressure causes damage to the microcapsule, internal linseed oil (LO) flows out and crosslinks the biodegradable polylactic acid (PLA) film in the presence of oxygen. Several parameters, such as capsule size, content, and curing temperature, are examined. In summary, the embedding of 5 wt% self-healing microcapsules yielded a healing efficiency of 94% at 70 ℃ in 20 min.

Recently, the safety of workers in industries has emerged as an important issue. In particular, when the workers are exposed to gaseous or liquid acids, it can lead to a serious problem to the human body. In the previous studies, we investigated the application of halochromic dyes on a nylon fabric for an acid-detecting textile chemosensor. In this study, bromocresol green was selected as a pH-indicating dye and its dyeing, fastness, and acid-sensing properties on a wool woven fabric were investigated. Bromocresol green in an aqueous solution of pH 2-4 showed maximum absorption at 444 nm with yellow color, whereas the maximum absorption changed to 616 nm showing blue color in a solution of pH 6 and over. Color yields (K/S) of bromocresol green on wool were dependent on the dyebath pH. The wool fabric showed greenish blue color when dyed at pH 4-7. The color of wool dyed at pH 3 was yellowish green, and the color at pH 2 was olive. The percent exhaustion of bromocresol green on wool increased with decreasing the dyebath pH, and a high exhaustion value of 98-99% could be obtained at pH 2-4. When the control sample, dyed at pH 4, was immersed in a solution of pH 3.5-4, its original greenish blue color was maintained. When immersed in a solution of pH 2-3, the color changed into olive with exhibiting a big color difference. The soaping process did not affect the color fastness. The wash and dry cleaning fastness of the wool fabric dyed at pH 3-5 was very good. The dry and wet rubbing fastness were excellent.

In this study, Polyimide (PI) fiber and non-woven fabric were fabricated for the manufacture of PI fiber high-temperature filter. The PI fiber was fabricated in two steps, and poly(amic acid) (PAA) could be manufactured by polymerizing 4,4'-oxydianiline (ODA) as an aromatic amine-based monomer and pyromellitic dianhydride (PMDA) as a solvent with N,N-dimethylacetamide (DMAc). PAA fibers were fabricated by wet spinning, PI fibers were manufactured by imidizing PAA fibers, and the properties of non-woven fabrics were investigated. To confirm the degree of imidization, various tests such as FT-IR analysis and shrinkage, heat resistance, deterioration analysis, maximum operating temperature, chemical resistance and dust collection efficiency were also performed.

Acid or base compounds in industries as well as acid rain are colorless so that they have difficulty in detecting. In the previous studies, we investigated a nylon chemosensor for detecting acidic liquids. In this study, we attempted to investigate a wool-based textile sensor using bromocresol purple as a pH-indicating dye. Dyeing properties of bromocresol purple on a wool woven fabric were investigated. The pH sensing property was also investigated by dipping the dyed wool fabric in aqueous solution with different pH values. Bromocresol purple in an aqueous solution showed maximum absorption at 432 nm with yellow color at a pH of 2-4, whereas the maximum absorption changed to 589 nm showing violet color at pH 7. Color yields (K/S) of bromocresol purple on wool were highly dependent on the dyebath pH. The wool fabric showed a strong orange color when dyed at pH 2. The color of wool dyed at pH 3-6 was yellowish brown or reddish brown, and the color at pH 7 was grayish blue. The percent exhaustion of bromocresol purple on wool increased as the pH of dyebath decreased, and a high exhaustion value of 98 to 99% could be obtained at pH 2-4. When the yellowish brown sample, dyed at pH 4, was immersed in a solution with a pH range of 4-5, its original color was maintained. Then, the color turned to yelloworange when immersed in a solution of pH 2-3. When immersed in a solution of pH 6, the color of the sample changed into brown. The color was also markedly changed into grayish purple when the sample was dipped in a solution of pH 7-8. The wash fastness of the wool fabric dyed at pH 3-5 was good to very good. The rubbing fastness were excellent, and dry cleaning fastness was very good.