Filament Diameter Research Articles

Influence of filament number and size on the basic properties of in situ made MgB2 wires

Monel-sheathed MgB2 wires with 6, 18 and 54 filaments of diameter 0.83 mm manufactured by Sam Dong Co., Ltd, have been subjected to twisting, drawing and rolling and measurements at low temperatures. R(T), I–V characteristics, critical currents and stress/strain tolerances of these wires were analyzed. Low reduction of critical current (⩽10%) by twisting between 50 mm and 12.5 mm was observed, especially for the wire with 54 filaments, which also showed the best strain tolerance to tension, ∼0.43% at 4.2 K. The engineering current density of the 18-filament wire was decreased by 56% by drawing from 0.83 mm to 0.4 mm, but improved by ∼24% by rolling from 0.83 mm to 0.64 mm. A small uninsulated coil was made from wire flattened from 0.83 mm to 0.64 mm by the wind and react process, resulting in a very high winding packing factor of 0.91 and also a high winding current density of 104 A cm−2 at B ⩽ 5.6 T. The presented properties are interesting for possible applications of these MgB2 wires in DC windings.

Targeted Micro-Phase separation – A generic design concept to control the elasticity of extrudable hydrogels

Hydrogels are ubiquitous in nature and technology. Controlling their mechanical properties and under-standing their complex microstructure is critical e.g. for 3D bioprinting or tissue engineering applications. Here a generic design concept for tuning the elasticity of extrudable gels at given polymer or particle concentration is presented. Targeted micro-phase separation leading to micro-heterogeneities (1–100 µm) yields high gel strength allowing for extrusion of uniform filaments with high shape accuracy as long as the heterogeneity length scale is small compared to the extruded filament diameter (>500 μm). Micro-mechanical and structural heterogeneity was enhanced in alginate hydrogels by accelerating crosslinking kinetics, corresponding to gel elasticity variation of more than two orders of magnitude (17 Pa to 2300 Pa), enabling filament extrusion (1046 µm) with high shape fidelity. Introducing poly(vinylalcohol) into gelatin gels resulted in more heterogeneous materials with a 2-fold increase in elasticity (951 Pa to 1993 Pa) and thinner filaments (908 µm to 590 µm). Higher ionic strength in Laponite-based hydrogels induced nanoparticle aggregation, leading to higher elasticity (857 Pa to 2316 Pa) enabling smooth filament extrusion. Eliminating the often tacitly assumed hydrogel uniformity on the microscale provides additional degrees of freedom to achieve high gel strength without increasing polymer, particle or crosslinker concentration.

Environmental and Hydrogeochemical Controls of Spicular Geyserite in Opaline Hot Spring Deposits

AbstractSiliceous spicules are micro‐laminated geyserite deposits, or micro‐stromatolites, found around high temperature hot‐springs and geysers, associated with intermittent splashes of water. Understanding conditions of formation of these structures will give insights of critical parameters involved in prebiotic environments and early life. We provide a new data set around two geysers from the El Tatio hydrothermal field, Atacama Desert, Chile, a modern analogue for habitable environments on early Earth and Mars. Small spicules (<5 mm diameter) dominate in the near vent areas, whereas larger spicules (>5 mm diameter) form complex columnar structures in the distal vent (>0.3 m distance from the vent). Hydrodynamics, eruption periodicity, and environmental conditions modulate the temperature and cooling patterns around vents. During geyser eruptions, the temperature of water reaching the ground decreases with the distance from the vent. Cooling is stronger during the evenings, due to strong winds and cold air temperature. Rapid water cooling drives supersaturation of amorphous silica, and therefore precipitation rates increase significantly with distance from the vent. Cooling also controls changes in the bacterial communities, from thin filaments <1 μm diameter predominating closer to the vent, to 1–2 μm diameter filaments in the distal vent. Changes in the silica precipitation rate and biota may control the growth of spicules and the transition to columns. Estimated precipitation rates of silica provide a first approximation of the longevity of these structures and the timing for the formation of internal laminations. Microlamination will form in year time‐scales closer to the vent, and weeks farther from the vent.

Three-Dimensional Printing of Recycled Polypropylene and Activated Carbon Coatings for Harmful Gas Adsorption and Antibacterial Properties.

In recent years, the utilization of three-dimensional (3D) printing has been expanding due to advances in technology and economic efficiency. One of the 3D printing technologies is fused deposition modeling, which can be used to create different kinds of products or prototypes from various polymer filaments. In this study, the activated carbon (AC) coating was introduced to the 3D outputs printed using recycled polymer materials to impart multi-functions such as adsorption of harmful gas and antimicrobial activities. A filament of uniform diameter (1.75 μm) and a filter template in the form of a 3D fabric shape were prepared through the extrusion and 3D printing processes, respectively, of the recycled polymer. In the next process, the 3D filter was developed by coating the nanoporous AC, produced from the pyrolysis fuel oil and waste PET, on the 3D filter template through direct coating. The 3D filters coated with the nanoporous activated carbon showed the enhanced adsorption capacity of 1038.74 mg of SO2 gas and the antibacterial properties of 49% removal of E. coli bacteria. As a model system, a functional gas mask that has harmful gas adsorption abilities and antibacterial properties has been produced by a 3D printing process.

Design a Viable 3DP Processing for Producing Effective Controlled-Release Pesticide

Various factors such as solubility, volatility, spray drift, runoff, and photolysis prevent the pesticides to reach their desired location and realize their full potential. In this study, additive manufacturing is used to create a drug-loaded filament that can be used in Fused deposition modeling printing. The optimal printing parameters are printing temperature (170°C), hotbed temperature (25°C), printing speed 15 mm/s, filament diameter 1.55 mm, layer height 0.3 mm, nozzle diameter 0.4 mm and zero retraction speed and retraction distance. The PCL-based framework provides a scaffold for drug encapsulation and low melting temperature. The latter is the key to maintaining the integrity and chemical properties of the loaded drug. FTIR confirms the physical-mix nature of composite. XRD suggests that PCL and model drug became amorphous after printing. The PCL controlled-release can be realized through <i>in vitro</i> dissolution tests. Among the four kinetic models: the zero-order, first-order, Higuchi model, and Korsmeyer–Peppas model, the kinetic model for dissolution and drug release conforms to the Korsmeyer–Peppas model. This study provides a viable design of controlled-release pesticides by adjusting the release regulator content and type to meet the precision pest-control needs. This 3DP tablet has higher drug loading, controllable drug loading, stable drug release ability, UV shielding performance, and an easy manufacturing process. There is no need for expensive and special equipment to produce the desired functionality, which greatly reduces production costs and simplifies the production process.

Electrospun Zr-Doped CaO Sorbent for CO2 Capture.

A Zr-doped CaO sorbent for high-temperature CO2 capture was fabricated using electrospinning. The nanofiber sorbent with an average filament diameter of about 160 nm is characterized by an initial CO2 uptake capacity of 12.1 mmol/g, a specific surface area of 79 m2/g, an indentation Young's modulus of 520 MPa, and a hardness of 1.6 MPa. After 50 carbonation/decarbonation cycles, the sorbent has a decent CO2 uptake capacity of 9.7 mmol/g due to the uniform distribution of CaZrO3 in the CaO nanofibers to prevent CaO grain growth caused by CaCO3 sintering. It is revealed that the sorbent CO2 uptake capacity decreases both with an increase in the decarbonation temperature and with an increase in the CO2 concentration in the gas flow upon carbonation, where the sorbent CO2 uptake capacity is more sensitive to the decarbonation temperature than to the CO2 concentration in the gaseous stream during carbonation. It is assumed that the electrospun regenerable Zr-doped CaO sorbent is effective for removing CO2 from flue gases.

Hydrodynamic effects of non-uniform feed spacer structures on energy loss and mass transfer in spiral wound module

To find a balance between feed flow rate and energy penalty, the hydrodynamic effects of non-uniform feed spacer structures on energy loss and mass transfer in spiral wound reverse osmosis (RO) module were numerically simulated by the CFD method through adopting dumbbell-shaped filament. The user-defined function (UDF) was employed to satisfy the permeability boundary conditions of membrane surfaces. The hydrodynamic effects of different filament diameter ratios (DR, d2/d1) as well as the spacer mesh angle α were studied. The simulation results showed that the spacer configuration greatly affected the energy loss and mass transfer in the spiral wound module. The pressure drop rate increased with increasing space mesh angle and a mesh angle between 60° and 120° was recommended for bearable pressure drop. The specific helicity was introduced to measure the vorticity transported with the flow. The negative region of specific helicity can be used to represent the wake size easily. The feed spacer with varied cross-section has the potential to reduce the specific energy consumption. When DR decreases from 1.0 to 0.45, the wake length becomes longer, and the pressure drop rate decreases significantly by about 58.1%. By increasing the Reynolds number from 50 to 200, the averaged wall shear stress increases by more than 5.6 times, and the averaged permeate water flux increases by 18.2%. Thus, the recommended value of feed flow Re was about 200. This detailed numerical study is of great significance to improve the understanding of concentration polarization and energy loss suppression by the optimized feed spacer configuration.

Optimization of Freeform Reversible Embedding of Suspended Hydrogel Microspheres for Substantially Improved Three-Dimensional Bioprinting Capabilities.

Three-dimensional (3D) bioprinting demonstrates technology that is capable of producing structures comparable to native tissues in the human body. The freeform reversible embedding of suspended hydrogels (FRESH) technique involves hydrogel-based bio-inks printed within a thermo-reversible support bath to provide mechanical strength to the printed construct. Smaller and more uniform microsphere sizes of FRESH were reported to aid in enhancing printing resolution and construct accuracy. Therefore, we sought to optimize the FRESH generation protocol, particularly by varying stir speed and stir duration, in hopes to further improve microsphere size and uniformity. We observed optimal conditions at a stir speed of 600 rpm and stir duration for 20 h that generated the smallest microspheres with the best uniformity. Comparison of using the optimized FRESH to the commercial FRESH LifeSupport to bioprint single filament and geometrical constructs revealed reduced single filament diameters and higher angular precision in the optimized FRESH bio-printed constructs compared with those printed in the commercial FRESH. Overall, our refinement of the FRESH manufacturing protocol represents an important step toward enhancing 3D bioprinting resolution and construct fidelity. Improving such technologies allows for the fabrication of highly accurate constructs with anatomical properties similar to native counterparts. Such work has significant implications in the field of tissue engineering for producing accurate human organ model systems. Impact statement Freeform reversible embedding of suspended hydrogels (FRESH) is a method of sacrificial three-dimensional (3D) bioprinting that offers support to reinforce bio-ink extrusion during printing. During FRESH generation, the stir speed and stir duration of the mixture can significantly impact FRESH microsphere characteristics. In this study, we optimized FRESH microspheres to significantly improve resolution and accuracy in bioprinting. This advancement in FRESH-based 3D bioprinting technologies allows for the fabrication of highly accurate constructs with anatomical properties similar to native counterparts and has significant implications in the field of tissue engineering and translational medicine.

3D Printing of Baclofen Gastro-Floating Drug Delivery Systems: A Comparison Study with In vitro and In vivo Evaluation

This study aims to formulate baclofen gastro-floating drug delivery dosage forms in two different approaches using hot melt extrusion and FDM 3D printing and then compare the effectiveness and select the best formula from the two approaches for further characterization. The first approach involved the preparation of baclofen-loaded filament by HME and then FDM 3D printing of floating tablets with low infill percentages. The second approach involved the formulation of sustained-release tablets by HME and 3D printing of a gastro-floating device (GFD) that holds the tablet inside it. Prepared tablets were tested for drug content, in vitro floating behavior, and in vitro dissolution test, and the optimized formula was tested for DSC, FT-IR, and in vivo radiographic study. Filaments prepared by HME with a diameter of less than 1.3 mm were not printed. Variations in filament diameter affect the printing quality of the 3D printed tablets resulting in tablets' weight variation and failure to float sometimes otherwise tablets were successfully printed and remained floating for 12 hr. Formulas prepared by both approaches with the same composition were found to have significant different dissolution profiles due to the rigid structure formed by 3D printing compared to a compressed tablet. Formulation of the HME tablet and 3D printing of GFD were more reliable and were able to float for more than 12 hr. Optimized formula containing Eudragit RS-100 and ethyl cellulose as release modifier polymers, released the drug and remained floating over 12 hr and this was confirmed by x-ray imaging of Albino rabbit. Formulation of sustained-release tablets by HME and inserting them into 3D printed GFD were found to be superior in terms of producing floating dosage forms compared to 3D printed tablets with low infill percentage.

Improving diameter measurement from Fraunhofer diffraction with fringe segment splicing.

Fraunhofer diffraction is an easy but powerful method for measuring the diameter of a thin filament. In practice, however, the diffraction pattern attainable is always subject to limits imposed by various imperfections in real systems, such as small angle approximation and sensor threshold, thus degrading the measurement resolution. In this Letter, we propose a method of fringe segment splicing for improving the diameter measurement from Fraunhofer diffraction. The fringe segment is chosen from a real diffraction pattern and is used to reproduce an ideal diffraction fringe, where the theoretical estimates give the best approximation to the observations. The problem of diameter measurement is solved in the spatial frequency-domain with an ideal diffraction fringe. Our results show that the relative error in this method is less than 0.1% and is far superior to that of previous methods.

Mineral-impregnated carbon-fiber (MCF) composites made with differently sized fly-ash geopolymers for durable light weight and high temperature applications

For a wide application of carbon-fiber reinforcement in large-scaled, lightweight construction, mineral-impregnated carbon-fiber (MCF) composites provide a promising alternative to rebar or reinforcement made of non-metallic fibers and polymer matrix. The penetration ability of the aluminosilicate particles is a key factor for a stable, reproducible impregnation and the maximal reinforcing efficiency of continuous fiber geopolymer composites.The work at hand focuses on the influence of the particle sizes of geopolymer precursors on the processing quality, microstructural development and final composite performance regarding the flexural, tensile and pullout behavior. Three differently sized fly ash (FA) sources were used to impregnate a carbon fiber heavy tow before curing at 75 °C. FA particles in the same size range as the filament diameter proved to be the most efficient, enhancing both mechanical properties of MCF and its bond to concrete matrix, well beyond the effects induced by other, coarser precursors. The results of the microscopic investigation, μCT, thermal gravimetric analyzes and mercury intrusion porosimetry measurements show that the use of this particle fraction resulted in the best fiber-matrix distribution over the cross-section, densest microstructure and highest fiber volume fraction in the impregnated yarn. Furthermore, the geopolymerization kinetics of all FAs at ambient temperature and at 75 °C were determined by isothermal calorimeter, showing an increase in the reaction rate with elevated curing temperature and higher particle finesse.

Mechanical properties of thermoplastic filament stitched carbon fiber reinforced composites

In recent years, the use of composites has attracted great interest in both academia and industry, especially due to their lightness and mechanical properties. In this study, acrylonitrile butadiene styrene (ABS), poly(ethylene-co-methacrylic) acid (EMAA) and ethylene vinyl acetate (EVA) filaments were produced in a single screw extruder. The produced filaments were integrated into composite materials by stitching method, and then, the mechanical properties of the filaments and composites were investigated. According to the tensile test results, it is concluded that the stitching process affects the mechanical properties of the composite material. The strength of the composite material produced with EVA filament with a maximum diameter of 1mm increased by 23%. Apart from these, the composite materials produced with 1mm ABS and 0.6mm and 0.8mm EMAA filaments increased by an average of 15%. There was no significant change in the elongation of the composite material produced with 0.6mm, 0.8mm, and 1mm diameter filaments. The elongation of the composite material produced with only 1mm diameter ABS filament increased by 12%. The elongation values of the composite material prepared with 0.6mm diameter EMAA and EVA polymers decreased also by 15%.

Aqueous Two-Phase Enabled Low Viscosity 3D (LoV3D) Bioprinting of Living Matter.

Embedded 3D bioprinting has great value for the freeform fabrication of living matter. However, embedded 3D bioprinting is currently limited to highly viscous liquid baths or liquid-like solid baths. In contrast, prior to crosslinking, most hydrogels are formulated as low-viscosity solutions and are therefore not directly compatible with bioprinting due to low shape fidelity and poor print stability. The authors here present a method to enable low-viscosity ink 3D (LoV3D) bioprinting, based on aqueous two-phase stabilization of the ink-bath interface. LoV3D allows for the printing of living constructs at high extrusion speeds (up to 1.8 m s-1 ) with high viability due to its exceedingly low-viscosity. Moreover, LoV3D liquid/liquid interfaces offer unique advantages for fusing printed structures, creating intricate vasculature, and modifying surfaces at higher efficiencies than traditional systems. Furthermore, the low interfacial tension of LoV3D bioprinting offers unprecedented nozzle-independent control over filament diameter via large-dimension strand-thinning, which allows for the printing of an exceptionally wide range of diameters down to the width of a single cell. Overall, LoV3D bioprinting is a unique all-aqueous approach with broad material compatibility without the need for rheological ink adaption, which opens new avenues of application in cell patterning, drug screening, engineered meat, and organ fabrication.

IN VITRO EVALUATION OF A PILE LOOP KNITTED SCAFFOLD FOR MYOCARDIAL TISSUE ENGINEERING USING C2C12 CELLS

Pile loop knitted scaffold has attracted attention for being used as a three dimensional (3D) biocompatible material particularly for the application of myocardial tissue engineering. In this research, nonintermingled, textured polyethylene terephthalate (PET) multifilament yarn with a filament count of 48 was used for producing a pile loop knit structure to investigate if structure could provide an appropriate microenvironment for the seeded murine C2C12 myoblasts in case of increasing in filament diameter (20.7 micron versus 9.1 micron from the previous study). The resulting structure had a pore network mainly consisting of macropores of 100-200 µm that were well interconnected with micropores (&amp;lt;90 µm). Furthermore, the mean values of the Young’s modulus of the structures at 20% strain were 240.67 kPa in the warp direction, and 85.73 kPa in the weft direction, which can be claimed not to be far from those declared in the literature for the human heart muscle. In addition, the cyclic loading-unloading test revealed no creep in the fabric after 100 cycles. According to the results of the WST-1 assay, the 48 filament-based scaffold was non-cytotoxic for C2C12 cells that were able to proliferate properly on the scaffold, which was visualized by SEM and confocal images. In this respect, pile loop knit structures keep promising results for being used as a cardiac patch.

Apparent thermal conductivity of PAN-based carbon fibre tow based on infrared thermography measurements

Currently, the apparent thermal conductivity of carbon fibre (CF) is measured using contact- and noncontact-type thermal conductivity methods. The contact-type method exhibits measurement non-uniformity in the CF thickness direction that does not allow uniform sampling; the error occurrence rate is known to be high. Meanwhile, in the noncontact-type method, the fibre porosity and tow gap results in a lower accuracy and similarly high error occurrence rate. Therefore, this study aims to provide a quantitative method of measuring the thermal conductivity of polyacrylonitrile (PAN)-based 12 K CF tows with a filament diameter of 7 µm using Fourier’s law of conduction and a thermal imaging camera. This method is expected to overcome the limitations of the conventional contact- and noncontact-type techniques. Using the proposed method, the average thermal conductivity of the PAN-based 12 K CF tow was measured to be approximately 21.28 W/m·K.

Marimo nanocarbons composed of a cup-stacked carbon nanofilaments as anode catalyst support for enhanced power performance of direct methanol fuel cells

Marimo nanocarbon(MNC) derived from C2 H4 and C3H6 contain many carbon nanofilaments (CNFs) with small filament diameters, whereas C2H6 and C3H8 contain many CNFs with large filament diameters. MNC(C2H4) and MNC(C3H6) pore sizes were approximately 25 nm, and MNC(C2 H4) and MNC(C3H6) specific surface area tended to be larger (C3H6). As a result, mesoporous MNC with small pore sizes can be synthesized using highly reactive alkanes as raw materials. The higher the carbon number of the raw material, the more functional groups and MNC(C2H4) and MNC(C3H6) were observed, as well as the more side chains and amorphous components. The highest surface functional group ratio was found in MNC(C3H8), while the lowest was found in MNC(C3H6). The stacking angle of graphene in CNF is gentler in MNC(C2H6) and MNC(C3H8), according to XRD results, and crystallinity is also higher in MNC (C3H8). As a result, high crystallinity MNC can be synthesized using low reactivity alkanes as raw materials. Finally, when used as a catalyst support for DMFCs, MNCs with more functional groups can improve power generation performance.

Analysis of PLA/PHB Biopolymer Material with Admixture of Hydroxyapatite and Tricalcium Phosphate for Clinical Use.

One trend in tissue engineering and regenerative medicine is the development of degradable composite polymers. The aim of this study was the comprehensive analysis of Polylactic acid (PLA)/Polyhydroxybutyrate (PHB) + Hydroxyapatite (HA)/Tricalcium phosphate (TCP) material from filament production to mechanical testing of samples with different infills and the production of an implant replacement for an intervertebral disc. Filament Maker-Composer 450 (3devo; Netherlands) was used to produce filaments. Experimental samples and the implant for the intervertebral disc were made using FDM technology using a DeltiQ2 3D printer (Trilab, Czech Republic). Mechanical testing of experimental samples was performed on an Inspekt TABLE 5 kN (Hegewald & Peschke, Nossen, Germany). Microscopic analysis, cytotoxicity test, and filament diameter analysis using descriptive statistics were also part of the focus. The results of the analysis of the diameter of the filament show that the filament meets the prescribed standard. The cytotoxicity test for PLA/PHB + HA/TCP material showed no toxicity. Microscopic analysis showed an even distribution of the ceramic component in the composite polymer. Mechanical testing showed a reduction in mechanical properties with 75% and 50% of the filling of experimental samples. All experimental samples subjected to mechanical testing showed higher tensile and compressive strength values compared to the values of the mechanical properties of vertebral trabecular bones, as reported in the literature. It can therefore be concluded that the material under investigation, PLA/PHB + HA/TCP appears to be a suitable candidate for hard tissue replacement.

Dynamic evolution of membrane biofouling in feed channels affected by spacer–membrane clearance and the induced hydrodynamic conditions

Membrane biofouling is regarded as a Gordian knot in applying reverse osmosis and nanofiltration for water treatment. It occurs in the feed spacer channels of spiral wound membrane elements. The influence of feed spacer structure on hydrodynamic condition and biofouling development remains yet to be fully understood. This study aims to quantify the dynamic evolution and spatial distribution of biomass in feed spacer channels, and reveal the great importance of spacer–membrane clearance in the biofouling development. Four kinds of feed spacers with the same thickness (28 mil) but different clearance width, by varying filament diameter (0.4, 0.45, 0.55 and 0.6 mm), were used. A relatively long-term (20 d) biofouling experiment was conducted by using a feed solution of lower bacterial load and nutrient dosage. Results showed that the “shear stress effect” dominated the early stage of biofouling as biofilm was first attached to the low-shear regions, regardless of the spacer–membrane clearance width. In the middle and late stage, the “blocking effect” emerged with the continuous accumulation of biomass, as was especially the case in the feed channel with narrow spacer–membrane clearance. In this period, biofilm was prone to deposit and block the narrow flow passage between the spacer filaments and membrane surface, which decreased the uniformity of flow field, expanded the flow “dead zone” area, boosted the feed channel pressure (FCP) drop, and resultantly accelerated the rate of membrane biofouling. Enhancement of the “shear stress effect” under an appropriate range of spacer–membrane clearance width and thus channel porosity, as well as customed design of feed spacer geometries according to specific fouling locations are suggested for the future optimization of feed spacer.

Wet-spinning of TEMPO-oxidized lignocellulose nanofibrils and functionalization of the filament with Ag nanoparticles

Wet spinning was studied for lignocellulose nanofibrils (TOLCNF) obtained by TEMPO oxidation and mechanical defibrillation of deep eutectic-like solvent-treated lignocellulose. First, the morphological characteristics, water retention value, and specific surface area of the TOLCNF were studied. The effects of the TOLCNF concentration (1.5, 2.0, and 2.5 wt%) and spinning rate (0.1, 1.0, and 10 mL/min) on the wet-spun filament diameter, orientation index, and tensile properties were studied. With an increase in the TOLCNF concentration, the average diameter increased, whereas the orientation index and tensile strength decreased. An increased spinning rate resulted in an increased orientation index and tensile strength but a decrease in the average diameter. To further extend their applicability, Ag nanoparticles (AgNPs) were grown in situ on the filament surface using UV irradiation. Spherical AgNPs with diameters of 30 to 90 nm were observed using scanning electron microscopy. An increased AgNP content improved the tensile strength and elastic modulus of the filaments.

3D-Printed Piezoelectric Porous Bioactive Scaffolds and Clinical Ultrasonic Stimulation Can Help in Enhanced Bone Regeneration.

This paper presents a comprehensive effort to develop and analyze first-of-its-kind design-specific and bioactive piezoelectric scaffolds for treating orthopedic defects. The study has three major highlights. First, this is one of the first studies that utilize extrusion-based 3D printing to develop design-specific macroporous piezoelectric scaffolds for treating bone defects. The scaffolds with controlled pore size and architecture were synthesized based on unique composite formulations containing polycaprolactone (PCL) and micron-sized barium titanate (BaTiO3) particles. Second, the bioactive PCL-BaTiO3 piezoelectric composite formulations were explicitly developed in the form of uniform diameter filaments, which served as feedstock material for the fused filament fabrication (FFF)-based 3D printing. A combined method comprising solvent casting and extrusion (melt-blending) was designed and deemed suitable to develop the high-quality PCL-BaTiO3 bioactive composite filaments for 3D printing. Third, clinical ultrasonic stimulation (US) was used to stimulate the piezoelectric effect, i.e., create stress on the PCL-BaTiO3 scaffolds to generate electrical fields. Subsequently, we analyzed the impact of scaffold-generated piezoelectric stimulation on MC3T3 pre-osteoblast behavior. Our results confirmed that FFF could form high-resolution, macroporous piezoelectric scaffolds, and the poled PCL-BaTiO3 composites resulted in the d33 coefficient in the range of 1.2-2.6 pC/N, which is proven suitable for osteogenesis. In vitro results revealed that the scaffolds with a mean pore size of 320 µm resulted in the highest pre-osteoblast growth kinetics. While 1 Hz US resulted in enhanced pre-osteoblast adhesion, proliferation, and spreading, 3 Hz US benefited osteoblast differentiation by upregulating important osteogenic markers. This study proves that 3D-printed bioactive piezoelectric scaffolds coupled with US are promising to expedite bone regeneration in orthopedic defects.