Print Materials Research Articles

A 3D Printed Pumpless Nonaqueous Organic Redox Flow Cell

Redox flow batteries (RFBs) have considerable promise in addressing the ever-increasing demands for robust energy storage devices. The nature of these devices makes it possible to create storage with potential applicability at multiple size scales1. However, conventional RFBs require energy to pump the liquid electrolyte, reducing the overall system efficiency, and limiting its viability to mid- and large-scale operations only2. Eliminating the pumping load can improve overall efficiency and create opportunities for mobile applications. In this work, we demonstrate a 3D printed prototype of a pumpless non-aqueous organic RFB that induces flow in the electrolyte from sinusoidal rocking motion. The body of the flow cell was created using 3D printing, allowing us to modify and adapt geometry easily during testing.First, the compatibility of the 3D-printed material was studied by testing the chemical stability of widely available additive manufacturing materials under RFB conditions. Then, we evaluated the performance of this pumpless system using an easily scalable, soluble, and stable one electron donor phenothiazine derivative, N-(2-(2-methoxyethoxy)ethyl)phenothiazine (MEEPT) which has been widely studied for RFB applications3. We used 0.25 M MEEPT and its bis(trifluoromethanesulfonyl)imide radical cation salt (MEEPT-TFSI) as a redox-active couple in 0.5 M tetraethylammonium bis(trifluoromethanesulfonyl)imide (TEATFSI)/acetonitrile (MeCN). Our results suggest an inversely proportional empirical relationship between limiting current density and the frequency of sinusoidal motion due to varying mass transfer rates. After 100 cycles in this symmetric cell with an area specific resistance of 2.62 Ωcm2, we achieved a capacity retention of 63% and an average Coulombic efficiency of 96%, with minimal sign of decomposition of the redox couple when analyzed post-cell cycling.The results of this study can be used for 3D printing material selection in numerous electrochemical devices that use organic solvents, including flow cells, supercapacitors, and lithium-ion batteries. Using sinusoidal motion to drive electrolytes instead of a pump can increase the theoretical efficiency and decrease the overall size of a flow cell. This makes it attractive in wearable applications where biomechanical motion can be harnessed.1 Wang, W. et al. Recent Progress in Redox Flow Battery Research and Development. Advanced Functional Materials 23, 970-986 (2013). https://doi.org:10.1002/adfm.2012006942 Tian, C. H., Chein, R., Hsueh, K. L., Wu, C. H. & Tsau, F. H. Design and modeling of electrolyte pumping power reduction in redox flow cells. Rare Metals 30, 16-21 (2011). https://doi.org:10.1007/s12598-011-0229-13 Milshtein, J. D. et al. High current density, long duration cycling of soluble organic active species for non-aqueous redox flow batteries. Energy & Environmental Science 9, 3531-3543 (2016). https://doi.org:10.1039/C6EE02027E

Accessible melt electrowriting three-dimensional printer for fabricating high-precision scaffolds

Melt electrowriting (MEW) is an established 3D printing technology for producing high-resolution scaffolds for tissue engineering. Commercial MEW devices are expensive while having limited processing capabilities, which limits their accessibility and widespread use. Herein, we report an easy-to-assemble and inexpensive ($2000) MEW printer based on an off-the-shelf automated dispensing machine with user-friendly controls and a custom-designed MEW printhead capable of printing polymers with a melting point of up to 260 °C. Using the gold standard printable material, poly(ε-caprolactone) (PCL), this printer can deposit 3 μm diameter fibers at 50 μm spacing, demonstrating that the highest quality of scaffolds can be produced on the low-cost MEW system. Stability in printing is improved by maintaining a relative humidity of 30–35 %, ensuring nozzle conditions are optimal, and minimizing bubbles in the polymer melt. Key printing parameters such as a 3 kV applied voltage, 75 °C heating temperature, 100 kPa air pressure, and 30 G nozzle size are critical for high accuracy, achieving 100 μm fiber spacing and layer stacking up to 30 layers without fiber breakage. The printer effectively creates complex scaffold geometries, showcasing its precision and suitability for advanced tissue engineering applications. Overall, this study promotes low-cost MEW technology by establishing a guideline on building an accessible but capable MEW printer and providing a crucial experimental foundation toward achieving high-accuracy scaffolds.

Conductive collagen/polypyrrole-b-polycaprolactone hydrogel for bioprinting of neural tissue constructs.

Bioprinting is increasingly being used for fabrication of engineered tissues for regenerative medicine, drug testing, and other biomedical applications. The success of this technology lies with the development of suitable bioinks and hydrogels that are specific to the intended tissue application. For applications such as neural tissue engineering, conductivity plays an important role in determining the neural differentiation and neural tissue regeneration. Although several conductive hydrogels based on metal nanoparticles (NPs) such as gold and silver, carbon-based materials such as graphene and carbon nanotubes and conducting polymers such as polypyrrole (PPy) and polyaniline were used, they possess several disadvantages. The long-term cytotoxicity of metal nanoparticles (NPs) and carbon-based materials restricts their use in regenerative medicine. The conductive polymers, on the other hand, are non-biodegradable and possess weak mechanical properties limiting their printability into three-dimensional constructs. The aim of this study is to develop a biodegradable, conductive, and printable hydrogel based on collagen and a block copolymer of PPy and polycaprolactone (PCL) (PPy-block-poly(caprolactone) [PPy-b-PCL]) for bioprinting of neural tissue constructs. The printability, including the influence of the printing speed and material flow rate on the printed fiber width; rheological properties; and cytotoxicity of these hydrogels were studied. The results prove that the collagen/PPy-b-PCL hydrogels possessed better printability and biocompatibility. Thus, the collagen/PPy-b-PCL hydrogels reported this study has the potential to be used in the bioprinting of neural tissue constructs for the repair of damaged neural tissues and drug testing or precision medicine applications.

Custom Shoe Sole Design and Modeling Toward 3D Printing.

This study introduces a design procedure for improving an individual’s footwear comfort with body weight index and activity requirements by customized three-dimensional (3D)-printed shoe midsole lattice structure. This method guides the selection of customized 3D-printed fabrications incorporating both physical and geometrical properties that meet user demands. The analysis of the lattice effects on minimizing the stress on plantar pressure was performed by initially creating various shoe midsole lattice structures designed. An appropriate common 3D printable material was selected along with validating its viscoelastic properties using finite element analysis. The lattice structure designs were analyzed under various loading conditions to investigate the suitability of the method in fabricating a customized 3D-printed shoe midsole based on the individual’s specifications using a single material with minimum cost, time, and material use.

Patient Contentment Regarding Health Education Services at King Saud Medical City in Riyadh, Saudi Arabia.

Health education enhances healthcare outcomes and patient satisfaction, and with digitalized methods, it is gaining popularity in high-income nations. Effective education promotes behavioral change, treatment adherence, and overall satisfaction while maintaining interpersonal communication.Despite the strides made in medical advancements for diagnosis and treatment, interpersonal communication remains the primary conduit for information exchange, particularly manifested through health education dialogues between medical practitioners and patients. A cross-sectional study was conducted at King Saud Medical City (KSMC), Riyadh, Saudi Arabia, to assess patient satisfaction with health education services. Data were collected through a structured questionnaire. Data were analyzed by IBM SPSS Statistics for Windows, Version 29 (Released 2021; IBM Corp., Armonk, New York, United States). This study on patient satisfaction with health education at KSMC in Riyadh included 225 participants, predominantly females (67.6% (n=152), mean age 38.5 years). Diabetes was the most prevalent (21.3%, n=48) among participants. Doctors were the primary source of health advice (46.2%, n=104). Structural aspects received high satisfaction (mean score of 31.8), surpassing healthcare provider delivery (mean score of 24.9) and print materials (mean score of 22.7). Demographically, occupation significantly impacted contentment (p-value=0.002), with students exhibiting the highest scores. Logistic regression highlightedpatients' occupation (aOR=1.498) and patients' level of education (aOR=0.420) as predictors of contentment. This study highlighted high satisfaction with structural aspects of health education. Occupation, particularly among students, significantly impacts contentment. Tailoring education strategies based on occupation and education levels is crucial for improved patient satisfaction.

Manufacturing and testing of pliers to weld 3D printing filaments

Abstract The advent of affordable three-dimensional printers has unlocked new possibilities for small business owners and hobbyists to convert their digital designs into tangible objects. However, during the production process, a lot of material ends up as waste because of improper storage or unused plastic fibers. This paper discusses the existing market products that aim to tackle these issues. Additionally, we introduce a specially designed pair of welding tongs that make it effortless to join plastic fibers utilized in fused deposition modeling printers. The paper presents a prototype of the tongs and provides a summary of the optimal welding temperatures for different printing materials. Finally, the conclusion evaluates the strength of the fibers after the welding process based on the results obtained from a testing mechanism.

An approach towards the development of an inclusive subject environment using additive manufacturing technologies

This research aims to identify the principles of designing the objects of the inclusive environment with the employment of additive manufacturing technologies, and to discover methods and techniques for creating an inclusive objective environment using the example of our own development. The results of the survey, which has been directed to investigate the topicality of the problem of inclusiveness in Ukraine and the means of its solution, are presented in the article. In the course of work, the principal peculiarities of three-dimensional (3D) modelling and printing technologies have been established, and promising areas of their application have been proposed. The principles of designing an inclusive objective environment have been detected with the use of photogrammetry and 3D printing, due to which the model can be constructed by considering a person’s individual physical characteristics. Moreover, due to the wide range of materials for 3D printing, various types of objects can be realized. It gives great potential for the employment of 3D printing when designing an inclusive environment and considerably simplifies the manufacturing process while taking the individual characteristics of every person into consideration.

Mechanical Properties of Carbon Fiber Reinforced Materials for 3D Printing of Ankle Foot Orthoses

Mechanical Properties of Carbon Fiber Reinforced Materials for 3D Printing of Ankle Foot Orthoses

A mechanical characteristic capture method considering printing configurations for buildability modeling in concrete 3D printing

The structure failure modeling of 3D printing concrete (3DPC) during production is crucial for structure design, manufacturing process control and optimization. Serving as model inputs, the accuracy of 3DPC fresh material properties measurement highly affects the model prediction performance. The measured mechanical properties of freshly printed concrete strongly depend on the geometry, deformation and hardening process of used samples in testing. Herein, we propose an all-in-one method (AIOM) that synchronously considers these key factors (layer geometry, deformation, and hardening process) to more accurately capture the early-age mechanical performance distribution in printed structures. Different parametric-mechanical buckling models and two printable cementitious materials with distinct hardening characteristics (printable cement and printable geopolymer) were used to validate the performance of AIOM, with the traditional testing method, uniaxial unconfined compression test (UUCT), as the reference. Compared with UUCT, AIOM can improve the buildability prediction accuracy by 11.9 % to 50.8 % for different validation scenarios. This novel testing method for 3DPC fresh material properties contributes to improving the accuracy of 3DPC structure failure models, thereby facilitating a better production phase control for 3DPC.

Self-learning in the digital age: insights from high SES primary school students in Türkiye and Azerbaijan

ABSTRACT This study examines the self-learning sources and practices of 10–11-year-old primary school students from high socioeconomic backgrounds in Türkiye and Azerbaijan. Through semi-structured interviews with students and parents (n = 26), the research explores self-learning diversification and strategies in the digital age. Findings reveal that self-learning experiences do not differ significantly between the two countries. Both digital and physical resources are integral to students’ learning efforts. While there is a shift from print materials towards the internet, family and peers maintain their traditional significance, providing crucial support for students’ self-learning processes. Emotions play a key role in navigating the self-learning journey, where challenges such as managing the abundance of online information and avoiding inappropriate content persist. Family dynamics exhibit a spectrum of support, including both direct interaction and digital engagement. The research highlights the crucial roles of self-regulation, digital resources, and familial and peer support in fostering learning achievement among these students.

Additive Manufacturing Technology in the Furniture Industry: Future Outlook for Developing Countries

For the past few years, the adoption of 3D printing technology has benefited various manufacturing industries, including the furniture making industry. However, this adoption has been greatly seen in industrialized countries and lacking in developing countries. Therefore, to understand fully the capability of 3D printing and its benefits, this paper review discusses recent applications of 3D printing in the furniture industry and assesses the potential it can bring for developing countries’ furniture making industry, specifically in the Philippines and other developing countries in Asia. In addition, the drawbacks it brought to the industry, and the challenges that needed to be addressed are also discussed in the paper. The paper covers various 3D printing technologies such as material extrusion, sheet lamination, powder bed fusion, and vat photopolymerization, along with different materials currently used in the furniture industry. Numerous notable examples of applications of 3D-printed furniture are also presented. Based on the review paper, it was found that the most common 3D printing technologies used in the furniture industry are Material Extrusion (MEX) and Powder Bed Fusion (PBF) specifically Fused Deposition Modelling (FDM) and Selective Laser Sintering (SLS), respectively. The most common 3D printing materials used are Polyamide (PA), Polylactic acid (PLA), and recycled Polyethylene terephthalate glycol (PETG). The paper also discusses the possible adoption of 3D printing in developing countries and explores its potential to innovate traditional furniture manufacturing processes.

Influence of Layer Thickness of 3D Printed Polyamide Against Temperature

Polyamide is one of the materials in 3D printing that can produce valuable products to meet the needs of the industry. Previous studies have proven that the layer thickness of the 3D printed material and the increase in temperature affect the mechanical and physical properties. However, only a few studies involve polyamide material as a test material, especially in analyzing the influence of the layer thickness of the printed material and the increase in temperature on the mechanical and physical properties of polyamide. Therefore, the bending properties of polyamide with different layer thicknesses at 0.1 mm, 0.2 mm and 0.3 mm and the tensile properties of the material at different temperatures at room temperature, 75˚C and 110˚C will be studied. This study will involve polyamide (PA) materials printed at three different layer heights using the Fused Deposition Modelling (FDM) process. Bending and tensile tests at different temperatures from 27˚C to 110˚C are conducted using the Instron Universal Testing Machine. The study results show that the layer height of 0.3 mm exhibits the highest flexural strength at an average rate of 11.05 MPa compared to 0.1 mm (6.7 MPa) and 0.2 mm (9.6 MPa). The tensile strength decreases when the temperature elevates, making the temperature of 110˚C have the lowest tensile value (1.591 MPa) compared to the temperature of 75˚C (1.6MPa) and 27˚C (2.1MPa). Several material characterizations such as SEM, TGA, DMA, DSC and density have been performed to study the microstructure and influence of tensile test temperature on the mechanical properties of polyamide.

Fluorescent Polylactic acid composite incorporating lignin-based carbon quantum dots for sustainable 4D printing applications

Fluorescent 4D printing materials, as innovative materials that combine fluorescent characteristics with 4D printing technology, have attracted widespread interest and research. In this study, green lignin-derived carbon quantum dots (CQDs) were used as the fluorescent module, and renewable poly(propylene carbonate) polyurethane (PPCU) was used for toughening. A new low-cost fluorescent polylactic acid (PLA) composite filament for 4D printing was developed using a simple melt extrusion method. The strength of the prepared composite was maintained at 32 MPa, while the elongation at break increased 8-fold (34 % increase), demonstrating excellent shape fixed ratio (∼99 %), recovery ratio (∼92 %), and rapid shape memory recovery speed. The presence of PPCU prevented fluorescence quenching of the CQDs in the PLA matrix, allowing the composite to emit bright green fluorescence under 365 nm ultraviolet light. The composite exhibited shear thinning behavior and had an ideal melt viscosity for 3D printing. The results obtained demonstrated the versatility of these easy-to-manufacture and low-cost filaments, opening up a novel and convenient method for the preparation of strong, tough, and multifunctional PLA materials, increasing their potential application value.

Design of FDM fabricated poly-lactic acid parts with forced-air cooling speed as the new control parameter to tune its shape memory effect

Poly lactic acid (PLA) as one of the shape memory polymers has extensively been used as the material in the 3D printing by fused deposition modeling process. In this study, we introduced the forced-air cooling speed as new control parameter in the fabrication process. A commercial material extrusion printer was retrofitted with a control module of forced-air cooling system. The shape memory effects of the PLA printed in different cooling speeds from 0–5 m s−1 were first measured by submerging the printed coupon specimens into water bath at recovery temperature. It is found that the changes in dimensions were mainly anisotropic and dependent of the raster angle in printing, in addition to the controlled cooling speed. The shape memory strains were roughly in linear trend with the magnitude of cooling air speed. In other words, the shape memory effect of the PLA can be easily controlled by the cooling air speed in fabrication. X-ray diffraction measurement on the specimens before and after recovery treatment confirmed the shape memory effect was related to the partial crystallization of molecular structure. Moreover, the different cooling air speeds also induced different thermal stresses in the printed specimens which manifest its important role in the total shape memory strain. Finally, the proposed theoretical beam formulation for the recovery bending deflection was shown to have good prediction accuracy comparing with experimental measurements.

Consumer's perceptions and motivations on the consumption of fortified foods and 3D food printing

Consumer attitudes and acceptance of emerging technologies in the food sector, as well as their application, are determining factors for their successful implementation. In this study, a survey was conducted in order to better know and understand the perception, motivation and consumption associated with fortified foods and 3DPF (3-Dimensional Printing Food). Key points such as food neophobia and factors involved in the opinion forming process towards 3DPF were included in the questionnaire (namely, perceived benefits, willingness to consume, food engagement, preference for familiar foods and affinity with digital tools). The results showed that the gender influences the knowledge in 3D printing as a technology and that 51.6 % of consumers are willing to try 3DPF. Consumers who want healthy food adapted to their needs are also more receptive to foods produced on 3D printers. 54.1 % of consumers indicate that if 3DPF were nutritionally richer than an equal and/or existing product on the market, they would be willing to buy it. Respondents also mentioned fruit and vegetable by-products and fish with no commercial value as the most suitable raw materials for 3D printing. Thus, it can be concluded that there is a clear motivation to try 3DPF, providing an opportunity for their inclusion in the future food chain.

Advancing sustainable construction: Terracotta component development through extrusion-based 3d printing with local clay

This study examines the use of 3D printing technology in construction, specifically the use of local clay as the primary material for developing Terracotta components. The results demonstrate the feasibility and high print quality achievable with clay, establishing it as a viable material for 3D printing in construction. The analysis of physical properties, such as shrinkage, density, and water absorption, provides valuable insights. Thermal conductivity, also examined, contributes to a comprehensive understanding of material performance. The article identifies the optimal extrusion parameters for terracotta components. The evaluations show that the water absorption rates are within standards, and the density variation ranges from 1420 to 1466 kg/m³. Additionally, there is a direct correlation between thermal conductivity and density. The compressive strengths are diverse, ranging from 18 MPa to 33 MPa. While modulus of elasticity provides essential quantitative data for understanding the mechanical behavior of printed samples when subjected to various stresses. The internal structure significantly influences compression resistance in 3D printed bricks, emphasizing its importance in design. This research highlights the potential of 3D printing, specifically with clay, in sustainable construction. It encourages further exploration of its practical applications in the industry.

Feasibility and Preliminary Effects of a Social Media-Based Peer-Group Mobile Messaging Smoking Cessation Intervention Among Chinese Immigrants who Smoke: Pilot Randomized Controlled Trial.

Chinese immigrants experience significant disparities in tobacco use. Culturally adapted tobacco treatments targeting this population are sparse and the use is low. The low use of these treatment programs is attributed to their exclusive focus on individuals who are ready to quit and the wide range of barriers that Chinese immigrants face to access these programs. To support Chinese immigrant smokers at all levels of readiness to quit and address their access barriers, we developed the WeChat Quit Coach, a culturally and linguistically appropriate WeChat (Tencent Holdings Limited)-based peer group mobile messaging smoking cessation intervention. This study aims to assess the feasibility, acceptability, and preliminary effects of WeChat Quit Coach. We enrolled a total of 60 Chinese immigrant smokers in 2022 in New York City for a pilot randomized controlled trial (RCT) and a single-arm pilot test. The first 40 participants were randomized to either the intervention arm (WeChat Quit Coach) or the control arm (self-help print material) using 1:1 block randomization stratified by sex. WeChat Quit Coach lasted 6 weeks, featuring small peer groups moderated by a coach, daily text messages with text questions, and chat-based instant messaging support from the coach in response to peer questions. The next 20 participants were enrolled in the single-arm pilot test to further assess intervention feasibility and acceptability. All 60 participants were offered a 4-week supply of complimentary nicotine replacement therapy. Surveys were administered at baseline and 6 weeks, with participants in the pilot RCT completing an additional survey at 6 months and biochemical verification of abstinence at both follow-ups. Of 74 individuals screened, 68 (92%) were eligible and 60 (88%) were enrolled. The majority of participants, with a mean age of 42.5 (SD 13.8) years, were male (49/60, 82%) and not ready to quit, with 70% (42/60) in the precontemplation or contemplation stage at the time of enrollment. The pilot RCT had follow-up rates of 98% (39/40) at 6 weeks and 93% (37/40) at 6 months, while the single-arm test achieved 100% follow-up at 6 weeks. On average, participants responded to daily text questions for 25.1 days over the 42-day intervention period and 23% (9/40) used the chat-based instant messaging support. Most participants were satisfied with WeChat Quit Coach (36/39, 92%) and would recommend it to others (32/39, 82%). At 6 months, self-reported 7-day point prevalence abstinence rates were 25% (5/20) in the intervention arm and 15% (3/20) in the control arm, with biochemically verified abstinence rates of 25% (5/20) and 5% (1/20), respectively. WeChat Quit Coach was feasible and well-received by Chinese immigrants who smoke and produced promising effects on abstinence. Large trials are warranted to assess its efficacy in promoting abstinence in this underserved population. ClinicalTrials.gov NCT05130788; https://clinicaltrials.gov/study/NCT05130788.

GPU-accelerated OCT imaging: Real-time data processing and artifact suppression for enhanced monitoring of 3D bioprinted tissues and vascular-like networks

Optical coherence tomography (OCT) imaging technology has significant advantages in in situ and noninvasive monitoring of biological tissues. However, it still faces the following challenges: including data processing speed, image quality, and improvements in three-dimensional (3D) visualization effects. OCT technology, especially functional imaging techniques like optical coherence tomography angiography (OCTA), requires a long acquisition time and a large data size. Despite the substantial increase in the acquisition speed of swept source optical coherence tomography (SS-OCT), it still poses significant challenges for data processing. Additionally, during in situ acquisition, image artifacts resulting from interface reflections or strong reflections from biological tissues and culturing containers present obstacles to data visualization and further analysis. Firstly, a customized frequency domain filter with anti-banding suppression parameters was designed to suppress artifact noises. Then, this study proposed a graphics processing unit (GPU)-based real-time data processing pipeline for SS-OCT, achieving a measured line-process rate of 800[Formula: see text]kHz for 3D fast and high-quality data visualization. Furthermore, a GPU-based real-time data processing for CC-OCTA was integrated to acquire dynamic information. Moreover, a vascular-like network chip was prepared using extrusion-based 3D printing and sacrificial materials, with sacrificial material being printed at the desired vascular network locations and then removed to form the vascular-like network. OCTA imaging technology was used to monitor the progression of sacrificial material removal and vascular-like network formation. Therefore, GPU-based OCT enables real-time processing and visualization with artifact suppression, making it particularly suitable for in situ noninvasive longitudinal monitoring of 3D bioprinting tissue and vascular-like networks in microfluidic chips.

Ecotoxicity of 3D printing material polylactic acid (PLA) on sea urchin Paracentrotus lividus

In this study, the ecotoxicity of 3D printing material [polylactic acid (PLA)] was investigated with marine echinoderms; sea urchin Paracentrotus lividus. To achieve this goal, (i) fertilization success, spermiyotoxicity, and embriyotoxicity exposed to PLA concentrations (0.001, 0.005, 0.01, 0.1, and 1 g/L) were assessed for 72 h. For this purpose, our study is important to make comprehensive evaluations to ensure the safety of bioplastic formulations and to take measures to regulate the use of additives. At the same time, the additive used to increase the durability of bioplastic materials will also allow us to understand the long-term effects on ecosystems, wildlife, and human health. Our aim is to minimize possible harm and ensure that the overall environmental impact of bioplastics remains positive.

Conformal 3D Printing Algorithm for Surfaces and Its In Situ Repair Applications.

Conformal 3D printing can construct specific three-dimensional structures on the free-form surfaces of target objects, achieving in situ additive manufacturing and repair, making it one of the cutting-edge technologies in the current field of 3D printing. To further improve the repair efficacy in tissue engineering, this study proposes a conformal path planning algorithm for in situ printing in specific areas of the target object. By designing the conformal 3D printing algorithm and utilizing vector projection and other methods, coordinate transformation of the printing trajectory was achieved. The algorithm was validated, showing good adherence of the printing material to the target surface. In situ repair experiments were also conducted on human hands and pig tibia defect models, verifying the feasibility of this method and laying a foundation for further research in personalized medicine and tissue repair.