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This study systematically investigates the effects of the coaxial nozzle's inner nozzle diameter on the strength and gelation of filaments produced via extrusion-based 3D printing with in situ ionic crosslinking. In this system, bioink (sodium alginate solution) was extruded through the outer nozzle, and the ionic crosslinking solution (calcium chloride solution) was extruded through the inner nozzle. The outer nozzle diameter was fixed at 2.16 mm, and the inner nozzle diameter was varied among 1.19, 0.84, and 0.584 mm. The results indicate that, as the inner nozzle diameter decreased, filament strength decreased, and filament gelation became poorer. These findings highlight the importance of optimizing inner nozzle diameter for improved filament strength and gelation in extrusion-based 3D printing with in situ ionic crosslinking. [ABSTRACT FROM AUTHOR]

Products made from petroleum-derived plastic materials are linked to many environmental problems, such as greenhouse gas emissions and plastic pollution. It is desirable to manufacture products from environmentally friendly materials instead of petroleum-based plastic materials. Products made from biomass–fungi composite materials are biodegradable and can be utilized for packaging, construction, and furniture. In biomass–fungi composite materials, biomass particles (derived from agricultural wastes) serve as the substrate, and the fungal hyphae network binds the biomass particles together. There are many reported studies on the 3D printing of biomass–fungi composite materials. However, there are no reported studies on the biodegradation of 3D-printed samples from biomass–fungi composite materials. In this study, two types of biomass materials were used to prepare printable mixture hemp hurd and beechwood sawdust. The fungi strain used was Trametes versicolor. Extrusion based 3D printing was used to print samples. 3D-printed samples were left for five days to allow fungi to grow. The samples were then dried in an oven for 4 h at 120 °C to kill all the fungi in the samples. The samples were buried in the soil using a mesh bag and kept in an environmental chamber at 25 °C with a relative humidity of 48%. The weight of these samples was measured every week over a period of three months. During the testing period, the hemp hurd test samples lost about 33% of their original weight, whereas the beechwood sawdust samples lost about 30% of their original weight. The SEM (scanning electron microscope) micrographs showed the presence of zygospores in the test samples, providing evidence of biodegradation of the test samples in the soils. Additionally, the difference in peak intensity between the control samples and test samples (for both hemp hurd and beechwood sawdust) showed additional evidence of biodegradation of the test samples in the soils. [ABSTRACT FROM AUTHOR]

This paper reports an experimental study on the compatibility of human bronchial epithelial (HBE) cells in a collagen–alginate bioink. The compatibility was assessed using the culture well method with three bioink compositions prepared from a 10% alginate solution and neutralized TeloCol-10 mg/mL collagen stock solution. Cell viability, quantified by (live cell count—dead cell count)/live cell count within the HBE cell-laden hydrogel, was evaluated using the live/dead assay method from Day 0 to Day 6. Experimental results demonstrated that the collagen–alginate 4:1 bioink composition exhibited the highest cell viability on Day 6 (85%), outperforming the collagen–alginate 1:4 bioink composition and the alginate bioink composition, which showed cell viability of 75% and 45%, respectively. Additionally, the live cell count was highest for the collagen–alginate 4:1 bioink composition on Day 0, a trend that persisted through Days 1 to 6, underscoring its superior performance in maintaining cell viability and promoting cell proliferation. These findings show that the compatibility of HBE cells with the collagen–alginate 4:1 bioink composition was higher compared with the other two bioink compositions. [ABSTRACT FROM AUTHOR]

The article discusses the environmental impact of petroleum-derived plastics. Topics include the biodegradability and environmental benefits of biomass–fungi composites, which are made from agricultural waste and fungi; the optimization of growth and processing conditions to improve the physical properties and mechanical strength of these materials; and the advantages of 3D printing-based manufacturing methods.

This paper reports on an experimental investigation that used a full factorial design to study the main effects and the interaction effect of layer thickness and compaction thickness on the green part density in the binder jetting additive manufacturing of silicon carbide. A two-variable, two-level full factorial design was employed. The results show that the green part density was higher at the low level of layer thickness and at the high level of compaction thickness. These results can be useful in selecting the values of printing variables, enabling the fabrication of green parts with a desirable density that is crucial for advanced ceramic applications. [ABSTRACT FROM AUTHOR]

Stereolithography has been used to create ceramic parts with complex geometry that is difficult to achieve with conventional fabrication techniques. This study used stereolithography to print silica honeycomb structures with a commercial Formlabs Form2 printer. The printed samples were sintered at different temperatures, and the print shape was retained up to 1300°C, but significant distortion from partial melting occurred at 1400°C. Higher sintering temperatures lead to more shrinkage, but it is non‐uniform among directions, with the open cell plane shrinking more than the dense plane of the sample. As expected, the density of samples also increases with the sintering temperature. At higher sintering temperatures, there is an increase in cristobalite and a decrease in quartz, tridymite, and amorphous silica. Regarding mechanical properties, the out‐of‐plane compressive strength is approximately one order of magnitude higher than the in‐plane compressive strength. When compressed along the out‐of‐plane direction, the samples sintered at lower temperatures surprisingly exhibit higher strength, which is explained by the micro‐cracking mechanism. As expected, the samples sintered at higher temperatures display higher strength when compressed along the in‐plane direction. [ABSTRACT FROM AUTHOR]

To combat climate change, one approach is to manufacture products from biomass-fungi composite materials instead of petroleum-based plastics. These products can be used in packaging, furniture, and construction industries. A 3D printing-based manufacturing method was developed for these biomass-fungi composite materials, eliminating the need for molds, and enabling customized product design. However, previous studies on the 3D printing-based method showed significant shrinkage of printed samples. In this paper, an approach is proposed to reduce the shrinkage by incorporating ionic crosslinking into biomass-fungi composite materials. This paper reports two sets of experiments regarding the effects of sodium alginate (SA) and calcium chloride (CaCl2) on fungal growth and fungal viability. The first set of experiments was conducted using Petri dishes with fungi isolated from colonized biomass-fungi material and different concentrations of SA and CaCl2. Fungal growth was measured by the circumference of fungal colonies. The results showed that concentrations of SA and CaCl2 had significant effects on fungal growth and no fungal growth was observed on Petri dishes with 15% CaCl2. Some of these Petri dishes were also observed under confocal microscopy. The results confirmed the differences obtained by measuring the circumference of fungal colonies. The second set of experiments was conducted using Petri dishes with biomass-fungi mixtures that were treated with different concentrations of SA and exposure times in a CaCl2 (crosslinking) solution. Fungal viability was measured by counting colony-forming units. The results showed that the addition of the SA solution and exposure times in the crosslinking solution had statistically significant effects on fungal viability. The 2SA solution was prepared by dissolving 2 g of SA in 100 mL of water, the 5SA solution was prepared by dissolving 5 g of SA in 100 mL of water, and the crosslinking solution was prepared by dissolving 5 g of CaCl2 in 100 mL of water. The results also showed that fungal viability was not too low in biomass-fungi mixtures that included 2SA solution and were exposed to the crosslinking solution for 1 min. [ABSTRACT FROM AUTHOR]

Biomass–fungi biocomposite materials are derived from sustainable sources and can biodegrade at the end of their service. They can be used to manufacture products that are traditionally made from petroleum-based plastics. There are potential applications for these products in the packaging, furniture, and construction industries. In the biomass–fungi biocomposite materials, the biomass particles (made from agricultural waste such as hemp hurd) act as the substrate, and a network of fungal hyphae grow through and bind the biomass particles together. Typically, molding-based methods are used to manufacture products using these biocomposite materials. Recently, the authors reported a novel extrusion-based 3D printing method using these biocomposite materials. This paper reports a follow-up investigation into the effects of mixing parameters (mixing time and mixing mode) on fungal growth in biomass–fungi mixtures prepared for 3D printing and the effects of printing parameters (printing speed and extrusion pressure) on fungal growth in printed samples. The fungal growth was quantified using the number of fungal colonies that grew from samples. The results show that, when mixing time increased from 15 to 120 s, there was a 52% increase in fungal growth. Changing from continuous to intermittent mixing mode resulted in an 11% increase in fungal growth. Compared to mixtures that were not subjected to printing, samples printed with a high printing speed and high extrusion pressure had a 14.6% reduction in fungal growth, while those with a low printing speed and low extrusion pressure resulted in a 16.5% reduction in fungal growth. [ABSTRACT FROM AUTHOR]

The electromagnetic induction heating technology has the advantages of fast heating speed and cleanness, and can realize the rapid temperature curing of carbon fiber reinforced polymer (CFRP). In order to improve production efficiency and curing quality, a finite element model of induction heating CFRP was established, and the temperature field distribution and heating mechanism during induction heating of CFRP were analyzed. The correctness of the model and conclusion is verified by experiments. On this basis, the influence of current, diameter, frequency and distance on the heating rate is analyzed, and it is found that frequency has the greatest influence on the heating rate. In addition, the mathematical relationship between temperature field uniformity and entropy value is established, which provides a quantitative analysis method for the temperature field uniformity of induction heating CFRP. Through optimization analysis, it is obtained that for the CFRP mentioned in the article, the coil size is selected between 65 mm and 95 mm, and the spacing is between 3.5 mm and 6.5 mm, so that the temperature field has the best uniformity. [ABSTRACT FROM AUTHOR]