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Droplet microfluidics enable high-throughput screening, sequencing, and formulation of biological and chemical systems at the microscale. Such devices are generally fabricated in a soft polymer such as polydimethylsiloxane (PDMS). However, developing design masks for PDMS devices can be a slow and expensive process, requiring an internal cleanroom facility or using an external vendor. Here, we present the first complete droplet-based component library using low-cost rapid prototyping and electrode integration. This fabrication method for droplet microfluidic devices costs less than $12 per device and a full design-build-test cycle can be completed within a day. Discrete microfluidic components for droplet generation, re-injection, picoinjection, anchoring, fluorescence sensing, and sorting were built and characterized. These devices are biocompatible, low-cost, and high-throughput. To show its ability to perform multistep workflows, these components were used to assemble droplet "pixel" arrays, where droplets were generated, sensed, sorted, and anchored onto a grid to produce images. [ABSTRACT FROM AUTHOR]

Laser-directed energy deposition (L-DED) has emerged as a promising technique for prototyping and the rapid manufacturing of Ti-6Al-4V alloy components. However, the hierarchical and heterogeneous microstructure that forms during L-DED can potentially lead to localized mechanical property variations. As a result, the widespread application of L-DED Ti-6Al-4V depends on a thorough understanding of its local property heterogeneity. This study examines the mechanical properties of L-DED-fabricated Ti-6Al-4V alloy, with a particular focus on hardness and localized tensile properties within the build volume, to identify potential variations. The mechanical property heterogeneity of the alloy was assessed both in the as-deposited condition and after mill-annealing (MA) treatment. Interestingly, the hardness distribution in L-DED Ti-6Al-4V, whether in the as-deposited or MA condition, did not exhibit significant local variability. Local tensile strength variation was found to be influenced by the orientation of the columnar β grains. When these grains were oriented perpendicular to the tensile deformation direction, minimal heterogeneity in tensile strength was observed. In contrast, greater variation was perceived when the columnar β grains were aligned parallel (along the deposition direction) to the tensile deformation direction. Furthermore, the strain-to-failure was higher along the deposition direction than in the perpendicular orientation. Notably, the strain-to-failure of the L-DED Ti-6Al-4V alloy decreased following MA treatment, regardless of the grain orientations. No clear trend in strain-to-failure variation with sample location was observed in L-DED Ti-6Al-4V alloy, either in the as-deposited or MA conditions. The observed local heterogeneity in mechanical properties is discussed and explained based on microstructural features and their influence on deformation behavior in the L-DED Ti-6Al-4V alloy. [ABSTRACT FROM AUTHOR]

Cancer is a major cause of death globally, and early detection is a key to improving outcomes. Traditional diagnostic methods have limitations such as being invasive and lacking sensitivity. Immunosensors, which detect cancer biomarkers using antibodies, offer a solution with high sensitivity and selectivity. When combined with 3D printing, these immunosensors can be customized to detect specific cancer markers, creating rapid, cost-effective, and scalable diagnostic tools. The article reviews the principles behind immunosensors, different 3D fabrication methods such as Fused Deposition Modeling (FDM) and Stereolithography (SLA), and discusses how functionalization strategies, such as surface modifications, can enhance the sensitivity of these devices. The integration of 3D printing allows for the creation of complex sensor structures, offering advantages such as customization, rapid prototyping, and multi-material printing. These advancements make immunosensors arrays highly promising for early cancer detection, tumor profiling, and personalized medicine. The article also explores challenges like scalability, material biocompatibility, and the need for clinical validation. Future perspectives suggest the potential of integrating nanomaterials, multiplexed detection, and wearable technology to further improve the performance and accessibility of these diagnostic tools. [ABSTRACT FROM AUTHOR]

Additive manufacturing, particularly the Fused Deposition Modeling (FDM) technique, has garnered considerable interest across multiple industries owing to its capacity to efficiently and inexpensively fabricate intricate geometries. To ensure optimal performance and dependability, it is essential to comprehend the impact of FDM process parameters upon a mechanical properties of 3D-printed parts. The main objective of this work is to investigate the impact of FDM process parameters using Polylactic Acid (PLA) material. The research employs a experimental design utilizing the Box-Behnken approach. Multiple sets of PLA specimens are produced using various FDM process parameters, including air gap, extruder temperature, layer thickness, infill density, and raster angle. Each specimen's tensile strength is measured using a universal testing machine, and result obtained is statistically analyzed for identification of significant correlations between the process parameters and the mechanical performance of the printed parts. The results indicate that specific process parameters in the Fused Deposition Modeling (FDM) technique significantly affect the tensile strength of parts made from Polylactic Acid (PLA). The relationship between layer thickness and infill density and their impact on tensile strength, percent elongation, and maximum force is significant, underscoring the need for careful parameter optimization in the printing process. [ABSTRACT FROM AUTHOR]

Involute gears of all sizes and types are widely utilized in most machinery. Accurate generation of teeth flanks from the nominally required base circle is most vital in gear manufacturing, performance, and inspection. Despite the vital importance of the base circle in actual gear performance, it is not a widely used inspection parameter. Moreover, the size of base circle radius and geometrical center cannot be obtained by direct measurement. In this work, a new mathematical algorithm was developed to evaluate the base circle dimensions by measurement of only the teeth profiles. Measurement of the outer diameter is not required nor is the prior knowledge of any gear dimension such as its module or pressure angle. The evaluated base circle dimensions are then used to compute remaining dominant gear dimensions including its pressure angle. The developed approach was tested on an ideal gear model then applied to the flank points obtained by measurements performed on a Coordinate Measuring Machine (CMM) and by photogrammetry (PG). The experimental results were compared to those measured using a gear roll tester (GRT) and were found to be in very good agreement. The methodology and measurement procedure presented in this work are distinguished by their ability to measure the actual gear dimensions regardless of any tooth modification made to the profile or addendum during manufacturing. This makes the proposed work well-suited for reverse engineering and rapid prototyping reverse calculations. [ABSTRACT FROM AUTHOR]

Fused deposition modelling (FDM) is a fabrication process under research to find various application in the current engineering industry as because of its minimized production time and ease of manufacturing intricate shapes. The goal of this work is to replace the traditional pattern material "wood" with "polylactic acid (PLA)" during sand casting. The objective of this work is to replace the existing conventional wood pattern or metal pattern with pattern made up of "polylactic acid (PLA)" by Fused Deposition Modeling (FDM) and a split pattern for pulley is selected as the area of focus to analyze the effects of the process parameters as Layer thickness (mm), Print speed (mm/sec), Fill density (g/mm3) and to find optimal values of process parameters to minimize the surface roughness, minimize the dimensional error (pulley groove width Error), also to minimize the pattern weight. The experimental data collection is done by using the sampling technique Taguchi orthogonal array (L9). The collected data were analyzed for significance (using ANOVA) and numerically modelled by using Regression modelling and optimized values are noted for various parameters by using pareto spread of distance. [ABSTRACT FROM AUTHOR]

In addition to anatomical loss, removal of the full or portion of the orbit results in a facial deformity and psychological distress for the patient. This article details a practical case of prosthetic rehabilitation using digital workflow for an orbital deformity caused by post-COVID-19 Mucor mycosis. The main goal of this case study was to create a maxillofacial orbital prosthesis that is well-retained, simple to use, and accurate in terms of appearance. The study addresses the problems involved in fabricating the orbital prosthesis, particularly the unique dimensions and form of the defect, replicating the natural skin tone, and accomplishing retention by the most prudent and patient-friendly approach. Through this article, a digitised algorithm, using photogrammetry technique for facial scan, is suggested for fabricating the prosthesis. [ABSTRACT FROM AUTHOR]

Investigations into the various properties of granular matter composed of particles with defined shapes have gained increasing attention. Additive manufacturing, with its freedom of shape and rapid prototyping capabilities, has significantly contributed to these studies. However, this technique may introduce defects in the manufactured particles, which can significantly affect the properties of granular materials. The extent of these defects on particles of different shapes is investigated here. Particles of various shapes (cube, octahedron, quatropod, stellated octahedron, tetrahedron, and tetrapod) were manufactured and subsequently imaged using micro-Computed Tomography. The surface roughness, solidity, and convexity of the particles were quantified. Discrete element simulations of granular bed porosity, utilizing both idealized and real particle shapes, were conducted with different surface mesh resolutions and frictional parameters. A clear influence of the manufacturing process on the packing properties of 3D printed particles was identified. This influence is not uniform across all shapes and is directly correlated with the particle convexity. For numerical simulations, a shape-dependent correction of particle density and surface characteristics are imperative for each shape under consideration, despite the fact that the particles were manufactured using the same technique and material. [ABSTRACT FROM AUTHOR]

Fused Filament Fabrication (FFF) is one of the most popular extrusion based metal Additive Manufacturing (AM) Technologies, which has unique advantages in the rapid prototyping of thermoplastic materials, enabling the fabrication of metal parts with low mechanical anisotropy and no residual stress. However, the mechanical properties and dimensional accuracy of FFF printed parts are susceptible to changes in various printing parameters, which affects the FFF application in large-scale manufacturing. This study experimentally studied the effect of various printing parameters namely layer thickness (0.1, 0.2, 0.3, and 0.4 mm), raster angle (0°, 90°, + 45°/−45°, and 0°/90°), raster width (0.3, 0.35, 0.4, and 0.45 mm), and infill density (70, 80, 90, and 100%) on mechanical properties and dimensional accuracy of 316L stainless steel fabricated by FFF. The results showed that the infill density was the most important factor affecting the mechanical properties, followed by the layer thickness, and it was found that higher values of infill density and lower layer thickness result in better tensile strength. Layer thickness was also the main factor affecting the dimensional accuracy, which increased with the decrease in the layer thickness. [ABSTRACT FROM AUTHOR]

Laser powder bed fusion (LPBF) is a rapid prototyping technology with high forming accuracy, which can print complex metallic components applied in the aerospace field. The aluminum alloy parts manufactured by LPBF can better achieve lightweight structures than other metallic materials due to the combination of materials and structure. However, many metallurgical defects such as spherification, porosity, coarse grain, and crack are more likely formed inside the printed components during the LPBF process, resulting in the decline of properties of the aluminum alloy. In order to solve the above-mentioned problems, researchers have conducted in-depth exploration to improve the mechanical properties of LPBF fabricated Al parts. In this paper, the methods to improve the forming quality of aluminum alloy are explored from the direction of regulation strategies for microstructure and properties. The current research status of LPBF-processed aluminum alloy is discussed from the aspects of process parameter optimization, alloying element modification, reinforcing phase addition, and post-treatment. Furthermore, the microstructure and properties of LPBF-processed aluminum alloy are systematically reviewed. [ABSTRACT FROM AUTHOR]

With the development of 3D metal printers for rapid prototyping and industrial component production, heightened attention was directed towards post-processing operations for achieving precise surface quality and geometrical tolerances for these components. This paper investigated the orthogonal cutting of multi-material 3D printed workpieces using a coated cutting tool through finite element simulation. The workpieces featured different horizontal and vertical arrangements of layers composed of aluminum 7075-T6 alloy (Al), stainless steel 316 low alloy (SS), and Ti6Al4V alloy (Ti). The study explored the impacts of multi-material composition, coating thickness, and the rake angle of the cutting tool on machining forces, stress distribution, temperature distribution, and chip formation geometry. The results revealed a bimodal chip morphology in the machining process of horizontally arranged SS layers combined with other alloys. The SS layer resulted in a relatively uniform chip formation, while layers with two other materials exhibited a serrated chip formation. In contrast, a discontinuous chip formed when combining Al and Ti materials, as well as in the horizontally arranged layers made of Al, SS, and Ti alloys. The cutting force increased by 2.26 times when cutting workpieces with the horizontal arrangement of SS and Al layers compared to those with a single Al material. For the horizontal and vertical arrangement of layers made of Al and SS, von Mises stress values over the edge of the coated cutting tool significantly increased where the tool contacted the SS layer. Additionally, the horizontal arrangement of layers made of Al and SS materials caused the coated cutting tool to exhibit an extensive temperature distribution, with the maximum recorded temperature reaching 1448 °K. Increasing coating thickness led to a decrease in maximum principal stress at the surface of the tool and a rise in temperature at the cutting edge of the insert. [ABSTRACT FROM AUTHOR]

Background: Inferior vena cava filter (IVC) retrieval is most often routine but can be challenging with high morbidity in complex cases, especially those with an extended dwelling time. While risk of morbidity in complex retrievals is decreased with advanced filter retrieval techniques, deciding when and which to use these requires detailed pre-procedural planning. The purpose of our study was to evaluate patient-specific 3D printed anatomic IVC filter models for aiding complex IVC filter retrievals. Methods: All IVC filter retrieval patients between June 2021 and September 2022 at one academic medical hospital were prospectively screened. Nine met criteria for complex retrieval, and their CT images were used to 3D print patient-specific IVC and filter models. Models were used in pre-procedural planning and clinical utility was assessed using the Anatomic Model Utility Likert Questionnaire and estimations of the procedural and fluoroscopy time saved. Results: The usage of 3D printed models in pre-procedural planning had high clinical utility based on the Likert questionnaire (Anatomic Model Utility Points 366.7 ± 103.1). Using a model significantly increased confidence in planning (p = 0.03) and modified the treatment plan in seven cases. It also led to cost-efficient use of resources in the procedure suite with estimated reduction in procedure and fluoroscopy time of 29.0 [20.3] (p = 0.003) and 10.2 [6.7] (p = 0.002) minutes, respectively. Conclusion: 3D printed anatomic models for patients who require complex IVC filter retrieval demonstrated Likert-based high clinical utility and led to estimated reductions of procedural and fluoroscopy time. [ABSTRACT FROM AUTHOR]

This study explores the development of biofoundries, emphasizing the integration of synthetic biology with artificial intelligence (AI) and robotics. It outlines critical challenges such as the necessity for interdisciplinary collaboration and the development of hardware, software, and AI specific to biofoundry operations. To address these challenges, we recommend strategies like rapid prototyping, soft integration, and the strategic implementation of AI. We underscore the vital role of synthetic biology researchers in advancing biofoundry capabilities and advocate for collaborative, multidisciplinary efforts to optimize the development and functionality of biofoundries. [ABSTRACT FROM AUTHOR]

The possibility of obtaining a combined titanium-steel construction by directed energy deposition using vanadium or vanadium/nickel interlayers has been investigated. Vanadium wire VnPr-1, nickel wire NP1 grade, and welding wires Sv-08G2S, 316L, and MSG NiFe-1 grades were used for deposition on the end of the titanium plate VT1-0. The use of vanadium as an interlayer deposited on titanium makes it possible to provide a joining with a stable structure, steady hardness distribution, and acceptable manufacturability. The content of dissolved titanium in the vanadium layer has a negative effect on the subsequent deposition of steel, nickel, or iron-nickel alloy. Therefore, the titanium content was reduced to a level of less than 0.5% by the deposition of at least 4 vanadium beads. The results of tensile tests demonstrated that all specimens failed in the elastic section mostly along the interlayers between vanadium and subsequent layers of low-carbon steel, nickel, and iron-nickel alloys deposited on it. The greatest ultimate tensile strength is achieved in the specimen, which is a compound of titanium and steel through interlayers of vanadium and iron-nickel alloy, and constitutes 251 MPa. The only specimen was destroyed along the titanium-vanadium interlayer probably due to brittle ω–phase formation. [ABSTRACT FROM AUTHOR]

3D printing has revolutionized the fabrication and rapid prototyping of microfluidic devices. However, it remains challenging to achieve optically transparent microfluidic chips with 3D printing, which limits their applicability in high-resolution imaging applications. We present a paradigm-shifting, low-cost, and generalizable post-processing method to address this challenge. Our method is centered around the implementation of a novel post-processing equipment "Spinning Desicurer" which integrates solvent-free resin removal, surface smoothing, and efficient surface curing. Our method produces microfluidic devices with high optical transparency and can be readily used to image microscopic objects such as cells and microparticles with fine details. [ABSTRACT FROM AUTHOR]

Parts manufactured by additive manufacturing (AM) are criticized due to the high surface roughness. Roller burnishing is one of the post-processing processes which may be applied for reducing the roughness and asperities on surfaces of 3D printed parts. In this study, innovative zirconium oxide (ZrO2) reinforced acrylonitrile butadiene styrene (ABS) based composites have developed in filament form for 3D printing of roller burnishing rapid tools. The filaments of ABS-ZrO2 were extruded under the range of 230-240 °C of barrel temperature and 4-6 RPM of screw speed under heat treatment as per Taguchi L9 based experimentation. As per the mechanical properties concern of composite filament material, the combination of preheat treatment, 235 °C of barrel temperature, and 6 RPM of screw speed have been noted best setting (Young's modulus: 886.00 MPa). The filament preparation has been supported with such as x-ray diffraction (XRD), Fourier transforms infrared (FTIR), and microstructural analysis using metallurgical image analysis software (MIAS). A machine learning (ML) approach based on classification and regression trees (CART) has been utilized to predict the tensile peak and break strength. Finally, the 3D printed roller burnishing tool has significantly reduced the surface roughness after burnishing. [ABSTRACT FROM AUTHOR]

Emulsification processes are often found in the process industry and their evaluation is crucial for product quality and safety. Numerous methods exist to analyze critical quality attributes (CQA) such as the droplet sizes and droplet size distribution (DSD) of an emulsification process. During the emulsification process, the optical process accessibility may be limited due to high disperse phase content of liquid-liquid systems. To overcome this challenge, a modular, optical measurement flow cell is presented to widen the application window of optical methods in emulsification processes. In this contribution, the channel geometry is subject of optimization to modify the flow characteristics and produce high optical quality. In terms of rapid prototyping, an iterative optimization procedure via SLA-3D printing was used to increase operability. The results demonstrated that the flow cell resulting from the optimization procedure provides a broad observation window for droplet detection. [ABSTRACT FROM AUTHOR]

Advances in artificial intelligence (AI) have led to its application in many areas of everyday life. In the context of control engineering, reinforcement learning (RL) represents a particularly promising approach as it is centred around the idea of allowing an agent to freely interact with its environment to find an optimal strategy. One of the challenges professionals face when training and deploying RL agents is that the latter often have to run on dedicated embedded devices. This could be to integrate them into an existing toolchain or to satisfy certain performance criteria like real-time constraints. Conventional RL libraries, however, cannot be easily utilised in conjunction with that kind of hardware. In this paper, we present a framework named LExCI, the Learning and Experiencing Cycle Interface, which bridges this gap and provides end-users with a free and open-source tool for training agents on embedded systems using the open-source library RLlib. Its operability is demonstrated with two state-of-the-art RL-algorithms and a rapid control prototyping system. [ABSTRACT FROM AUTHOR]

Developing immersive learning systems is challenging due to their multidisciplinary nature, involving game design, pedagogical modelling, computer science, and the application domain. The diversity of technologies, practices, and interventions makes it hard to explore solutions systematically. A new methodology called Multimodal Immersive Learning Systems Design Methodology (MILSDeM) is introduced to address these challenges. It includes a unified taxonomy, key performance indicators, and an iterative development process to foster innovation and creativity while enabling reusability and organisational learning. This article further reports on applying design-based research to design and develop MILSDeM. It also discusses the application of MILSDeM through its implementation in a real-life project conducted by the research team, which included four initiatives and eight prototypes. Moreover, the article introduces a unified taxonomy and reports on the qualitative analysis conducted to assess its components by experts from different domains. [ABSTRACT FROM AUTHOR]

This study analyzed collaborative invention projects by teams of lower-secondary (13–14-year-old) Finnish students. In invention projects, student teams design and make materially embodied collaborative inventions using traditional and digital fabrication technologies. This investigation focused on the student teams' knowledge creation processes by examining how they applied maker practices (i.e., design process, computer engineering, product design, and science practices) in their co-invention projects and the effects of teacher and peer support. In our investigations, we relied on video data and on-site observations, utilizing and further developing visual data analysis methods. Our findings assist in expanding the scope of computer-supported collaborative learning (CSCL) research toward sociomaterially mediated knowledge creation, revealing the open-ended, nonlinear, and self-organized flow of the co-invention projects that take place around digital devices. Our findings demonstrate the practice-based, knowledge-creating nature of these processes, where computer engineering, product design, and science are deeply entangled with design practices. Furthermore, embodied design practices of sketching, practical experimenting, and working with concrete materials were found to be of the essence to inspire and deepen knowledge creation and advancement of epistemic objects. Our findings also reveal how teachers and peer tutor students can support knowledge creation through co-invention. [ABSTRACT FROM AUTHOR]

Objective: Bibliometrics was employed in this study to determine the research trends in the worldwide application of 3D printing technology to treat bone tumors over the previous 10 years. Methods: Published from 2013 to 2022, the papers related to bone tumors treated with 3D printing were located in Web of Science Core Collection (WoSCC), PubMed, and Scopus. The screened articles were included in this bibliometric study. From these papers in WoSCC, information on annual publications, journals, keywords, countries, authors, institutions, and cited references were extracted and visualized with CiteSpace (version 6.1.R6) software to investigate the state of bone tumor treatment using 3D printing as well as research hotspots. The Carrot2 online visualization tool and Vosviewer software (version 1.6.20) were employed to visualize the publications from PubMed and Scopus, respectively, in order to ascertain the most popular research topics from both databases. Results: A total of 606, 233, and 364 publications were obtained from WoSCC, PubMed, and Scopus, respectively, between the years 2013 and 2022. In WoSCC, the peak number of publications was found in 2021, with 145 publications published. Acta Biomaterialia (11 publications) and World Neurosurgery (10 publications) were the most prolific journals, and Biomaterials was the journal cited the most (244 times). Yong Zhou was the most productive author with 14 publications, while Kwok-Chuen Wong (69 citations) and William F Enneking, (69 citations) possessed the most citations. The country with the largest quantity of publications was China (207). Among all institutions, Shanghai Jiao Tong University produced the most publications (29). Rapid prototyping was the keyword with the strongest citation burst (4.73). 'Reconstruction', 'surgery', 'resection', and 'design' caught the significant attention of researchers. 3D-printed materials, pelvic reconstruction, mandibular reconstruction, computer-assisted surgical techniques, photothermal therapy, and in vitro experiments were recognized as hot subjects and trends in current research. The most frequently occurring topics in Scopus are not significantly different from those found in WoSCC. The most prevalent research areas in PubMed encompass implant, patient-specific, bioceramic, models, and pelvic. [ABSTRACT FROM AUTHOR]

The use of software simulators has a long tradition in robotics, allowing the rapid prototyping of behaviors thus saving time and cost. In recent years there has been an increased interest in the development of social robots and Socially Assistive Robots (SARs), for which interaction design, rather than movement and control issues are more important. This work describes the design, development and evaluation of a simulator software for the EVA robot, named EvaSIM. The EVA (Embodied Voice Assistant) robot is an open-source robotics platform created to support research in human-robot interaction. The EvaSIM simulator can interpret the codes of the scripts generated with the EVA visual programming language (VPL) as well as the codes generated with the EvaML language, an XML-based language for developing interactive sessions for the EVA robot. The simulator includes a Parser and an Execution module and GUI to enact the designed interactions. EvaSIM is capable of simulating the robot's multimodal interaction capabilities, emphasizing its social affordances. The simulator was evaluated in relation to its perceived usefulness, perceived ease of use, clarity and usability by 26 users. The SUS instrument was used to assess usability. Results indicate that the EvaSIM simulator is perceived by users as effective, useful and easy to use. Results were consistent among experienced and beginner users. [ABSTRACT FROM AUTHOR]

Although research has touted the value of making in educational settings, scant work has been done in formal school contexts utilizing quantitative methods. This could be attributed to the various challenges in integrating making in school settings. To fill in the gap, this study presents an approach to integrate making into science classes at the 3rd to 5th grade levels in a U.S. public school for four consecutive years (2015–2019). We examined the effect of the program on students' self-beliefs (self-efficacy, motivation, and self-concept) using a longitudinal quasi-experimental design. We also examined the effect of making on students' knowledge and skills using state testing data. Results suggest that when averaged across post school year surveys, students in maker classes (vs. control) reported higher self-efficacy beliefs in science and making as well as more interests in STEM-related careers. Moreover, over two school years, we observed that students in the control group experienced declines on some of our variables while our maker students did not. Data thereby speaks to the potential value and promise of integrating making into formal school settings. Practical implications are discussed. [ABSTRACT FROM AUTHOR]

Fused deposition modeling is frequently utilized for rapid prototyping and customized objects because it is affordable and open source. Three-dimensional (3D)-printed polylactic acid (PLA) samples were coated with polyurethane (PU) to achieve unique features like outstanding durability, and excellent surface finishing. Also, multi-walled carbon nanotube (MWCNT) nanoparticles have been inserted into PU coatings to enhance mechanical properties under a corrosion environment. This research coated the additive-manufactured PLA samples with the PU and PU/MWCNT for tensile, impact, microhardness, and pull-off tests. Additionally, the mechanical performance of the samples was evaluated after immersion in NaCl 3.5 wt% solution for 10, 20, and 30 days. The microstructure and chemical properties of the coated specimens were characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) techniques, and X-ray diffraction analysis (XRD). The addition of PU and PU/MWCNTs nanocomposite coatings enhanced the mechanical characteristics of the 3D-printed samples compared to the pure PLA. Among all samples, the PLA/PU/MWCNT samples demonstrated the best performance. When PLA was coated with PU/MWCNTs, its tensile strength increased from 32 to 39 MPa when exposed to a NaCl 3.5 wt% solution. Although the impact strength of the PU/MWCNTs-coated samples slightly decreased with longer immersion time in the NaCl solution, it remained significantly higher than that of the uncoated PLA samples. Analysis of the microstructure revealed that the MWCNTs filled gaps and microcracks, resulting in a more uniform and compact protective layer. In summary, incorporating MWCNTs into the coating improved the mechanical properties of additive-manufactured PLA samples. [ABSTRACT FROM AUTHOR]

Background: 3D printers have gained prominence in rapid prototyping and viable in creating dimensionally accurate objects that are both safe within a Magnetic Resonance Imaging (MRI) environment and visible in MRI scans. A challenge when making MRI-visible objects using 3D printing is that hard plastics are invisible in standard MRI scans, while fluids are not. So typically, a hollow object will be printed and filled with a liquid that will be visible in MRI scans. This poses an engineering challenge however since objects created using traditional Fused Deposition Modeling (FDM) 3D-printing techniques are prone to leakage. Digital Light Processing (DLP) is a relatively modern and affordable 3D-printing technique using UV-hardened resin, capable of creating objects that are inherently liquid-tight. When printing hollow parts using DLP printers, one typically requires adding drainage holes for uncured liquid resin to escape during the printing process. If this is not done liquid resin will remain inside the object, which in our application is the desired outcome. Purpose: We devised a method to produce an inherently MRI-visible accessory using DLP technology with low dimensional tolerance to facilitate MRI-guided breast biopsies. Methods: By hollowing out the object without adding drainage holes and tuning printing parameters such as z-lift distance to retain as much uncured liquid resin inside as possible through surface tension, objects that are inherently visible in MRI scans can be created without further post-processing treatment. Results: Objects created through our method are simple and inexpensive to recreate, have minimal manufacturing steps, and are shown to be dimensionally exact and inherently MRI visible to be directly used in various applications without further treatment. Conclusion: Our proposed method of manufacturing objects that are inherently both MRI safe, and MRI visible. The proposed process is simple and does not require additional materials and tools beyond a DLP 3D-printer. With only an inexpensive DLP 3D-printer kit and basic cleaning and sanitation materials found in the hospital, we have demonstrated the viability of our process by successfully creating an object containing fine structures with low spatial tolerances used for MRI-guided breast biopsies. [ABSTRACT FROM AUTHOR]

Prosthetic rehabilitation refers to the process of restoring or improving a patient's physical function, appearance, and quality of life through the use of prosthetic devices. Providing cost-effective prosthetic rehabilitation for transfemoral amputees remains a challenging task. Traditional prosthetic fabrication methods, such as casting and lamination, are expensive and prone to fitting errors. Moreover, these methods are time-consuming, labor-intensive, and lack data-driven precision, heavily relying on artisanal expertise for socket fitting. However, recent advancements in rapid prototyping technologies, in conjunction with Reverse Engineering through 3D scanners, offer a promising alternative. This scoping review explores the current state of knowledge in transfemoral prosthesis fabrication, with a focus on additive manufacturing (AM), RE, and computer-aided manufacturing (CAM) methods. A systematic database search on PubMed and LENS.ORG was conducted, followed by a thorough analysis of selected articles. The review highlights major research areas, including pressure/stress/strain distribution analysis at the socket-stump interface, gait cycle assessment, and developments in 3D printing of knee and ankle joints. Critical appraisals of each article provide valuable insights for future research and advancements in affordable prosthetic rehabilitation. In conclusion, the utilization of AM, RE, and CAM methods for TFP fabrication is in its infancy but holds immense potential for improving cost-effective solutions in this domain. [ABSTRACT FROM AUTHOR]

Microfluidic devices have immense potential for widespread community use, but a current bottleneck is the transition from research prototyping into mass production because the gold standard prototyping strategy is too costly and labor intensive when scaling up fabrication throughput. For increased throughput, it is common to mold devices out of thermoplastics due to low per-unit costs at high volumes. However, conventional fabrication methods have high upfront development expenses with slow mold fabrication methods that limit the speed of design evolution for expedited marketability. To overcome this limitation, we propose a rapid prototyping protocol to fabricate thermoplastic devices from a stereolithography (SLA) 3D printed template through intermediate steps akin to those employed in soft lithography. We apply this process towards the design of self-operating capillaric circuits, well suited for deployment as low-cost decentralized assays. Rapid development of these geometry- and material-dependent devices benefits from prototyping with thermoplastics. We validated the constructed capillaric circuits by performing an autonomous, pre-programmed, bead-based immunofluorescent assay for protein quantification. Overall, this prototyping method provides a valuable means for quickly iterating and refining microfluidic devices, paving the way for future scaling of production. [ABSTRACT FROM AUTHOR]

3D printing technology has revolutionized product development in numerous industries. Due to 3D printing, innovative ways of directly giving drugs to patients, anatomical models for surgical planning and training, and tailored prosthetics and other medical equipment are all within the realm of possibility in the medical industry. 3D printing in healthcare has sparked a paradigm shift in creating medical implants and prosthetics. As a result of their exceptional mechanical, thermal, electrical, and optical qualities, polymers and composites made of them have gained widespread use in the medical industry. In this review article, we look at the most recent and cutting-edge benefits of 3D printing technology to create medical products out of polymers and composites. This article summarizes recent findings in patient-specific medical device and prosthesis design and manufacture and anatomical model development for surgical training and planning. Various 3D printing techniques, i.e., stereolithography, fused deposition modeling, and selective laser sintering methods, were examined, along with the pros and cons. Finally, we discuss the importance of 3D printing, which could significantly alter how medical devices are designed and produced, enhancing healthcare services and improving patient outcomes. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM), a quickly changing field, is reshaping industries by producing novel and customized materials quickly and efficiently. AM deviates from conventional subtractive processes by enabling layer-by-layer production of products with computer-aided design software. This process offers unique advantages for niche applications, such as metamaterial properties. Numerous industries have adopted this adaptable and aesthetically pleasing technology. For 3D printing, nylon, known for its strength, durability, and flexibility, has become the material of choice, especially when creating complex objects. Though it suffers from some difficulties, such as stretching and shrinking, as the most common AM method for nylon, material extrusion takes advantage of its superior mechanical properties and reliability. The processes, morphological traits, and mechanical properties of the AM of nylon and nylon composite materials are all covered in this thorough review, which methodically focuses on the body of current research. Tensile, flexural strength, and hardness are the main mechanical properties explored in this review, considering subtleties found in previous research. The paper ends with a research analysis viewpoint, pointing out managerial and theoretical gaps based on the body of literature and advocating for more studies to improve AM procedures. This succinct but comprehensive review offers insightful guidance on overcoming obstacles and leveraging advances in AM materials. [ABSTRACT FROM AUTHOR]

The importance of geometrical control of three dimensional (3D) printable concrete without the support of formwork is widely acknowledged. In this study, a numerical model based on computational fluid dynamics was developed to evaluate the geometrical quality of a 3D printed layer. The numerical results were compared, using image analysis, with physical cross-sectional sawn samples. The influence of printing parameters (printing speed, nozzle height, and nozzle diameter) and the rheological behavior of printed materials (yield stress), on the geometrical quality of one printed layer was investigated. In addition, the yield zone of the printed layer was analyzed, giving insights on the critical factors for geometrical control in 3D concrete printing. Results indicated that the developed model can precisely describe the extrusion process, as well as the cross-sectional quality. [ABSTRACT FROM AUTHOR]

Digital fabrication techniques, in recent decades, have provided the basis of a sustainable revolution in the construction industry. However, selecting the digital fabrication method in terms of manufacturability and functionality requirements is a complex problem. This paper presents alternatives and criteria for selection of digital fabrication techniques by adopting the multi-criteria decision-making technique. The alternatives considered in the study are concrete three-dimensional (3D) printing, shotcrete, smart dynamic casting, material intrusion, mesh molding, injection concrete 3D printing, and thin forming techniques. The criteria include formwork utilization, reinforcement incorporation, geometrical complexity, material enhancement, assembly complexity, surface finish, and build area. It demonstrates different multi-criteria decision-making techniques, with both subjective and objective weighting methods. The given ranking is based on the current condition of digital fabrication in the construction industry. The study reveals that in the selection of digital fabrication techniques, the criteria including reinforcement incorporation, build area, and geometrical complexity play a pivotal role, collectively accounting for nearly 70% of the overall weighting. Among the evaluated techniques, concrete 3D printing emerged as the best performer, however the shotcrete and mesh molding techniques in the second and third positions. [ABSTRACT FROM AUTHOR]

Some of the most metabolically diverse species of bacteria (e.g., Actinobacteria) have higher GC content in their DNA, differ substantially in codon usage, and have distinct protein folding environments compared to tractable expression hosts like Escherichia coli. Consequentially, expressing biosynthetic gene clusters (BGCs) from these bacteria in E. coli often results in a myriad of unpredictable issues with regard to protein expression and folding, delaying the biochemical characterization of new natural products. Current strategies to achieve soluble, active expression of these enzymes in tractable hosts can be a lengthy trial-and-error process. Cell-free expression (CFE) has emerged as a valuable expression platform as a testbed for rapid prototyping expression parameters. Here, we use a type III polyketide synthase from Streptomyces griseus, RppA, which catalyzes the formation of the red pigment flaviolin, as a reporter to investigate BGC refactoring techniques. We applied a library of constructs with different combinations of promoters and rppA coding sequences to investigate the synergies between promoter and codon usage. Subsequently, we assess the utility of cell-free systems for prototyping these refactoring tactics prior to their implementation in cells. Overall, codon harmonization improves natural product synthesis more than traditional codon optimization across cell-free and cellular environments. More importantly, the choice of coding sequences and promoters impact protein expression synergistically, which should be considered for future efforts to use CFE for high-yield protein expression. The promoter strategy when applied to RppA was not completely correlated with that observed with GFP, indicating that different promoter strategies should be applied for different proteins. In vivo experiments suggest that there is correlation, but not complete alignment between expressing in cell free and in vivo. Refactoring promoters and/or coding sequences via CFE can be a valuable strategy to rapidly screen for catalytically functional production of enzymes from BCGs, which advances CFE as a tool for natural product research. [ABSTRACT FROM AUTHOR]

Constructing gene networks in cells enables the efficient production of valuable substances and the creation of cells performing intended functions. However, the construction of a cellular network of interest, based on a design-build-test-learn cycle, is quite time-consuming due to processes mainly attributed to cell growth. Among the various available methods, cell-free systems have recently been employed for solving network testing problems using cells, because cell-free systems allow quick evaluations of test networks without waiting for cell growth. Although cell-free systems have the potential for use in rapid prototyping platforms, the correlation between the in vitro and in vivo activities for each genetic part (e.g. promoter) remains enigmatic. By quantifying mRNA and its encoded protein in a cell, we have identified appropriate culture conditions where cellular bottlenecks are circumvented and promoter activities are correlated with previous in vitro studies. This work provides a foundation for the development of molecular breadboard research. [ABSTRACT FROM AUTHOR]

The work is devoted to the study of bimetallic structures "titanium-steel" by electron beam freeform fabrication with the use of niobium and copper interlayers. A metallographic study of the deposited interlayers is carried out. The hardness distribution over the samples is shown. Technological issues according to deposition of niobium on titanium and steel on copper are pointed out. Tensile testing results reveal that the obtained structures have an ultimate tensile strength of 150–228 MPa and the fracture is located at the niobium-copper alloy side or at the niobium interlayer. The need to reduce the titanium content in niobium due to the occurrence of intergranular penetration of copper is demonstrated. [ABSTRACT FROM AUTHOR]

Architected porosity in masonry structures can be created by transforming stock materials into a lattice of interlocking units through an automated batch process. Porous masonry forms numerous enclosed cavities for thermal performance and reduces material usage while maintaining structural integrity. This work investigates the potential and limits of digital tectonics of porous masonry through a complete process of design, manufacturing, and construction. The confluence of digital fabrication with tectonic exploration opens new dimensions unattainable by traditional stereotomy. Interlocking materials inspired by Abeille vault and digital stereotomy have made rapid progress. Following the theory of poetic construction, this work proposes that masonry construction should evoke visual or haptic enhancement through the fulfillment of pragmatic functions. We formulated a design challenge for a confined dry masonry wall for the envelope of the 2226 building. It assumes batch-cutting bespoke units out of large blocks of high-strength foam. Through a process of cutting and reassembling, the stock material is topologically expanded into a porous structure. A series of prototypes were developed to explore novel articulation, structural and thermal performance, and economical manufacturing. One can perceive the logic of porous construction through visual and haptic empathy. The materialization process interacts with the design masonry units and the interlocking mechanism. For future practice in masonry, the porosity should be planned at multiple scales (molecular scale, aggerate scale, construction scale) across the life cycle of the material. [ABSTRACT FROM AUTHOR]

Printed conductive polymer composites allow for the bespoke manufacture of products with complicated geometries, which is critical for rapid prototyping and adaptability of flexible electrical devices. However, it is still challenging to prepare environmentally friendly and sustainable conductive polymer composites with aqueous solvent systems which accomplish excellent printing and electromechanical properties at the same time. In this work, the effect of composite components on performance was explored, and orthogonal tests were utilized to discover the precise formulation of new green aqueous conductive polymer composites with superior performance. The printing accuracy of the conductive polymer composites was enhanced (printed circuit burrs less than 20 μm) and the dependability of the printed circuits as well as the failure mechanism during electrochemical migration (ECM) were thoroughly investigated. As a proof of concept, ultrahigh frequency (UHF) flexible linearly polarized antennae with read range forward surpassing 10 m was designed and printed. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) is a preferred industrial manufacturing method for modeling and rapid prototyping of physical systems. The final product in AM must have appropriate mechanical properties, such as flexural strength and be of good quality. The selection of printing parameters is essential for this reason. In this study, three critical printing parameters, such as layer thickness (100-200-300 µm), raster angle (0-30-60°), and infill density (40-60-80%) were examined. The analysis of variance method was used to look at the relationship between these parameters and the flexure strength of samples fabricated using the fused deposition modeling technique with polyethylene terephthalate glycol material. The experimental design process was performed using Taguchi L9 orthogonal design. Fuzzy logic-based modeling was applied to estimate the flexural strength. The results demonstrated that the infill density is the most important parameter affecting flexural strength compared to the other parameters. The highest strength of 57.76 MPa was achieved when the layer thickness, raster angle, and infill density were set to 100 µm, 60°, and 80%, respectively. The fuzzy logic provided a high-accuracy estimation of the flexural strength with a maximum percentage error of 2.65%. Consequently, it was determined that the model and experimental results were in agreement. [ABSTRACT FROM AUTHOR]

Powder-based laser-directed energy deposition (L-DED) enables rapid prototyping and production of complex geometry Inconel 718 parts for structural applications. However, the heterogeneous microstructure obtained by the L-DED could lead to non-uniform mechanical properties at room temperature. Therefore, evaluating the local heterogeneity in mechanical properties of L-DED manufactured Inconel 718 superalloy is important. The mechanical properties in terms of hardness and local tensile properties of Inconel 718 superalloy have been investigated within the sample volume manufactured by L-DED to determine the local variations in properties. The mechanical properties were compared under the as-deposition and standard solution treatment and aging (STA) conditions. The average hardness and tensile strength properties of L-DED Inconel 718 in as-deposition conditions were significantly lower, while the strain-to-failure is significantly higher than that of its wrought counterparts. STA leads the average mechanical properties of L-DED Inconel 718, which is equivalent to its wrought counterpart. The hardness varied along the deposition direction in as-deposited L-DED Inconel 718. Interestingly, the local variability in the hardness along the deposition direction in L-DED Inconel 718 was eliminated after STA. The tensile strength properties varied along the deposition direction and were found to be lowest near the surface. The local variation trend in tensile strength properties was the same even after STA. The local ductility followed a trend relative to the strength in L-DED Inconel 718. A careful assessment shows that local variation in the mechanical properties was significant along the deposition direction, while it was minimal along the scanning direction of L-DED Inconel 718 under as-deposition and STA conditions. The local heterogeneity in the mechanical properties in L-DED Inconel 718 is explained in terms of the respective microstructure and deformation characteristics. [ABSTRACT FROM AUTHOR]

This work presents an experimental and mechanical study on the tensile response of 3D-printed thermoplastic polyurethane membranes, to be used as stretchable members of novel seismic isolators. The examined specimens have been 3D-printed by fused deposition modeling at the Rapid Prototyping Laboratory of the University of Salerno. Cyclic tests performed at different strain rates are employed to characterize the mechanical response of such members and the dependence of preconditioning effects on the recovery time and the initial pretension of the specimens. The presented results show a marked hysteretic response, the fast recovery of residual strains with time, and an appreciable increase of the tangent tensile modulus along the loading phase of the stress–strain curve with growing values of the applied strain rate. [ABSTRACT FROM AUTHOR]

The role of carbide in additive manufacturing of nickel-based superalloy is significant and debated. The Ni–Fe–Cr–Al–Ti alloys with different content of carbon were designed and prepared using electron beam freeform fabrication with nickel-based powder-cored wire. The influence of the in-situ forming carbides on the printability, microstructure, and mechanical properties of the alloys was investigated. The role of the in-situ forming carbides in the precipitation of the γ′ phase and its function in suppressing the cracking mechanism was explored. The results showed that the in-situ forming TiC precipitated along the grain boundaries with diverse morphologies including long strips, feathers, and fish bones. With the increase of the proportion of TiC precipitated phase, the distribution of carbides gradually presents a continuous network structure. Moreover, the microhardness and tensile strength of the deposited samples were increased. The alloy with the highest content of in-situ forming TiC shows the highest microhardness (464.9 HV) and tensile strength (967.5 MPa at room temperature, 646.8 MPa at 850 °C). Furthermore, the in-situ forming TiC inhibited the precipitation and growth of γ′ phase by consuming Ti element and reducing the precipitation temperature of γ′ phase. Consequently, the solid-state cracks induced by the γ′ phase transition stress were suppressed effectively, and the printability of the alloy was improved. The above results comprehensively elucidate the roles of the carbide in additive manufacturing of nickel-based superalloy. [ABSTRACT FROM AUTHOR]

Background: Proximal humeral fractures (PHFs) are still controversial with regards to treatment and are difficult to classify. The study's objective is to show that preoperative planning performed while handling a three-dimensional (3D) printed anatomical model of the fracture can ensure a better understanding of trauma for both surgeons and patients. Materials and methods: Twenty patients (group A, cases) with complex PHF were evaluated preoperatively by reproducing life-size, full-touch 3D anatomical models. Intraoperative blood loss, radiographic controls, duration of surgery, and clinical outcomes of patients in group A were compared with 20 patients (group B, controls) who underwent standard preoperative evaluation. Additionally, senior surgeons and residents, as well as group A patients, answered a questionnaire to evaluate innovative preoperative planning and patient compliance. Cost analysis was evaluated. Results: Intraoperative radiography controls and length of operation were significantly shorter in group A. There were no differences in clinical outcomes or blood loss. Patients claim a better understanding of the trauma suffered and the proposed treatment. Surgeons assert that the planning of the definitive operation with 3D models has had a good impact. The development of this tool has been well received by the residents. The surgery was reduced in length by 15%, resulting in savings of about EUR 400 for each intervention. Conclusions: Fewer intraoperative radiography checks, shorter surgeries, and better patient compliance reduce radiation exposure for patients and healthcare staff, enhance surgical outcomes while reducing expenses, and lower the risk of medicolegal claims. Level of evidence: Level I, prospective randomized case–control study. [ABSTRACT FROM AUTHOR]

This paper proposes an effective approach to realise circular construction with concrete, and shows Unreinforced Masonry as a foundational building block for it. The paper outlines the importance of circularity in building structures. It specifically focuses on the impact of circular construction with concrete on improving the sustainability of the built environment in a rapidly urbanising world economy. Subsequently, the relevance of principles of structural design and construction of unreinforced masonry to achieve circularity is articulated. Furthermore, the paper presents and summarises recent developments in the field of Unreinforced Concrete Masonry (URCM) including digital design tools to synthesise structurally efficient shapes, and low-waste digital fabrication techniques using lower-embodied-emission materials to realise the designed shapes. The paper exemplifies these using two physically realised, full-scale URCM footbridge prototypes and a commercially available, mass-customisable building floor element, called the Rippmann Floor System (RFS). The paper also outlines the benefits of mainstream, industrial-scale adoption of the design and construction technologies for URCM, including accelerating the pathway to decarbonise the concrete industry. In summary, the paper argues that URCM provides a solution to significantly mitigate the carbon emissions associated with concrete and reduce the use of virgin resources whilst retaining its benefits such as widespread and cheap availability, endurance, fire safety, low maintenance requirements and recyclability. [ABSTRACT FROM AUTHOR]

The shift towards bio-economies of architectural fabrication necessitates particular consideration of how characterizing aspects of bio-materials such as heterogeneity and anisotropy impact the designed performance of architectural elements. These aspects must be integrated into the modelling and representation of architecture and must be instrumentalised for digital design and fabrication processes. The use of timber in construction is challenging due to its complex material behaviours, and therefore robust methods for predicting and modelling these are crucial for exploiting the timber resource more effectively. In light of this, we focus on developing a holistic and integrated digital modelling approach for glue-laminated timber construction elements that connects the digital design model to the specific material resource and incorporates its material complexity into design simulation workflows. We question the role of the lamella in the glulam blank and trace its agency through a series of four disparate projects, from an initially silent and generic constituent of the blank to a key, operative actor in the design of performance-graded timber products through the added specificity of material composition and a liberation of its form. The first project develops a modelling approach that connects material specification and lamella sizing to free-form timber element geometries. It uses principles of industrial glulam production and knowledge of the anisotropic nature of timber to speculate on new forms of glulam blanks that could arise from a deeper engagement with the glue-lamination process. The second project looks further back in the timber value chain at the processing of the specific forest resource into tailored building elements, attaching a material specificity to the lamella. The third project expands the modelling and prototyping of non-standard glulam blanks into considerations of timber waste streams and aesthetics. The final project aims to further speciate the lamella by tailoring its form as well as its material composition to respond to simulated performance demands. Through these projects we outline the development of a novel digital framework that begins as a modelling approach for free-form glulam beams and grows to accommodate the mapping and allocation of specific, heterogeneous input material. As the digital framework matures, increasingly detailed and interlinked digital simulations of mechanical performance are integrated. [ABSTRACT FROM AUTHOR]

The application of microfluidic devices as next-generation cell and tissue culture systems has increased impressively in the last decades. With that, a plethora of materials as well as fabrication methods for these devices have emerged. Here, we describe the rapid prototyping of microfluidic devices, using micromilling and vapour-assisted thermal bonding of polymethyl methacrylate (PMMA), to create a spheroid-on-a-chip culture system. Surface roughness of the micromilled structures was assessed using scanning electron microscopy (SEM) and atomic force microscopy (AFM), showing that the fabrication procedure can impact the surface quality of micromilled substrates with milling tracks that can be readily observed in micromilled channels. A roughness of approximately 153 nm was created. Chloroform vapour-assisted bonding was used for simultaneous surface smoothing and bonding. A 30-s treatment with chloroform-vapour was able to reduce the surface roughness and smooth it to approximately 39 nm roughness. Subsequent bonding of multilayer PMMA-based microfluidic chips created a durable assembly, as shown by tensile testing. MDA-MB-231 breast cancer cells were cultured as multicellular tumour spheroids in the device and their characteristics evaluated using immunofluorescence staining. Spheroids could be successfully maintained for at least three weeks. They consisted of a characteristic hypoxic core, along with expression of the quiescence marker, p27kip1. This core was surrounded by a ring of Ki67-positive, proliferative cells. Overall, the method described represents a versatile approach to generate microfluidic devices compatible with biological applications. [ABSTRACT FROM AUTHOR]

To search for dark matter candidates with masses below O (MeV), the SPLENDOR (Search for Particles of Light dark mattEr with Narrow-gap semiconDuctORs) experiment is developing novel narrow-bandgap semiconductors with electronic bandgaps on the order of 1–100 meV. In order to detect the charge signal produced by scattering or absorption events, SPLENDOR has designed a two-stage cryogenic HEMT-based amplifier with an estimated charge resolution approaching the single-electron level. A low-capacitance (∼ 1.6 pF) HEMT is used as a buffer stage at T = 10 mK to mitigate effects of stray capacitance at the input. The buffered signal is then amplified by a higher-capacitance (∼ 200 pF) HEMT amplifier stage at T = 4 K. Importantly, the design of this amplifier makes it usable with any insulating material—allowing for rapid prototyping of a variety of novel detector materials. We present the two-stage cryogenic amplifier design, preliminary voltage noise performance, and estimated charge resolution of 7.2 electrons. [ABSTRACT FROM AUTHOR]

The development of 3D spiral microfluidics has opened new avenues for leveraging inertial focusing to analyze small fluid volumes, thereby advancing research across chemical, physical, and biological disciplines. While traditional straight microchannels rely solely on inertial lift forces, the novel spiral geometry generates Dean drag forces, eliminating the necessity for external fields in fluid manipulation. Nevertheless, fabricating 3D spiral microfluidics remains a labor-intensive and costly endeavor, hindering its widespread adoption. Moreover, conventional lithographic methods primarily yield 2D planar devices, thereby limiting the selection of materials and geometrical configurations. To address these challenges, this work introduces a streamlined fabrication method for 3D spiral microfluidic devices, employing rotational force within a miniaturized thermal drawing process, termed as mini-rTDP. This innovation allows for rapid prototyping of twisted fiber-based microfluidics featuring versatility in material selection and heightened geometric intricacy. To validate the performance of these devices, we combined computational modeling with microtomographic particle image velocimetry (μTPIV) to comprehensively characterize the 3D flow dynamics. Our results corroborate the presence of a steady secondary flow, underscoring the effectiveness of our approach. Our 3D spiral microfluidics platform paves the way for exploring intricate microflow dynamics, with promising applications in areas such as drug delivery, diagnostics, and lab-on-a-chip systems. [ABSTRACT FROM AUTHOR]

Additive manufacturing of polymers is used for rapid prototyping and in specific applications for the fabrication of final products. As the application range grows to the industrial sector, functional parts require better mechanical properties and tighter tolerance ranges. Short-fiber reinforced polymers can handle higher stresses and significantly less deformation than raw AM polymers, but their surface roughness and viscoelastic behavior are poorly understood. The authors perform the dynamical mechanical analysis, line, and surface roughness characterization of fused filament fabricated composites in this work. Mainly, Onyx, a short carbon-filled fiber nylon thermoplastic composite, was used in three different build orientations: flat, on-edge, and upright. Then, the effect of build orientation on the viscoelastic and roughness properties is discussed. Results showed that despite using the same raw material, printing direction has a moderate impact on the viscoelastic behavior and a significant effect on the surface roughness of the part. For instance, a difference of 25 °C in the Tg was observed between the on-edge and upright build orientation, with the latter the highest. Also, the flat print orientation presented the lowest values in the z-roughness of all the three build orientations analyzed. [ABSTRACT FROM AUTHOR]

Self-expanding frames for minimally invasive implants are typically made from nitinol wires and are heat treated to maintain the desired shapes. In the process of heat treatment, nitinol structures are placed in a high-temperature oven, while they are confined by a fixture. During this process, nitinol exerts a high amount of force. Accordingly, a fixture requires high mechanical strength and temperature resistance; this is why fixtures are typically made from metals. The use of metal fixture also increases the turnaround time and cost. However, accelerating this process is beneficial in many applications, such as rapid development of medical implants that are patient-specific. Inspired by the use of sacrificial layers in microfabrication technology, here we propose a novel method for shape setting nitinol wires using a sacrificial metal fixture. In this process, the nitinol wires are first aligned inside copper hypotubes. Next, the forming process is done using hand-held tools to shape complex geometrical structures, annealing the nitinol reinforced by copper, and then selectively etching copper hypotubes in ammonium persulfate solutions. In this process, other sacrificial cores, which are 3D printed or cast from low-cost polymers, are also used. This combination of polymeric cores and minimal use of metals enables reducing the cost and the turnaround time. As a proof of concept, we showed that this process was capable of fabricating springs with mm or sub-mm diameters. The result showed a change of less than 5% in the intended diameter of the nitinol spring with diameters ranging from ~ 0.7 to 1.9 mm, which confirms copper as a suitable sacrificial fixture to obtain the desired complex geometry for nitinol. A metric, based on the elastic strain stored in copper is suggested to predict the possible variation of the intended dimensions in this process. Finally, to demonstrate the potential of this method, as proof of concept, we fabricated NiTi wire frames designed for anchoring through the atrial septum. These frames demonstrated septal defect occluders that were designed based on a patient's cardiac image available in the public domain. This low-cost rapid fabrication technique is highly beneficial for a variety of applications in engineering and medicine with specific applications in rapid prototyping of medical implants. [ABSTRACT FROM AUTHOR]

Additive manufacturing transforms the industry by integrating innovative and intelligent technology, resulting in less material waste and faster prototyping. However, qualitative ambiguities are a significant barrier to digital fabrication methods to manufacture essential parts that require great precision and accuracy. However, qualitative ambiguities are a substantial barrier to digital fabrication methods to manufacture crucial parts that demand higher precision and accuracy. As a result, process monitoring techniques during production are becoming increasingly important. Acoustic emission testing is a prominent nondestructive testing approach that has demonstrated its capacity to detect and locate minute and internal developing cracks, allowing for real-time damage monitoring. This study briefly discussed different additive manufacturing processes, their influential parameters, and monitoring techniques, with particular emphasis on acoustic emission techniques. This study provides extensive recommendations for process monitoring of fused deposition modeling, powder bed fusion and directed energy deposition methods using acoustic emission testing. The different approaches used for handling the acoustic emission data and the effect of defects on acoustic emission signal parameters are also reviewed in this study. [ABSTRACT FROM AUTHOR]

This manuscript explores the applications and advancements in three-dimensional (3D) printing with a focus on incorporating additive particles with unique properties into polymer composites. The benefits of 3D printing, such as design flexibility and rapid prototyping, are discussed along with the challenges of incorporating reinforcement materials with the polymer matrix. The review emphasizes the importance of achieving a homogeneous distribution of particles in the polymer matrix for filament fabrication in 3D printers. Thus, this review introduces the optimum method to produce a homogenous distribution of particles in the polymer matrix for fabricating filament for a FDM 3D printer. The use of filler particles enhances the properties of 3D printed parts, increasing their density, stiffness, and tribological performance, thereby expanding their applicability in industrial and biomedical fields. [ABSTRACT FROM AUTHOR]