Filament Diameter Research Articles

Non-destructive evaluation of melt-extruded part quality using in situ data

PurposeThis study aims to collect real-time, in situ data from polymer melt extrusion (ME) 3D printing and use only the collected data to non-destructively identify printed parts that contain defects.Design/methodology/approachA set of sensors was created to collect real-time, in situ data from polymer ME 3D printing. A variance analysis was completed to identify an “acceptable” range for filament diameter on a popular desktop 3D printer. These data were used as the basis of a quality evaluation process to non-destructively identify spatial regions of printed parts in multi-part builds that contain defects.FindingsAnomalous parts were correctly identified non-destructively using only in situ collected data.Research limitations/implicationsThis methodology was developed by varying the filament diameter, one of the most common reasons for print failure in ME. Numerous other printing parameters are known to create faults in melt extruded parts, and this methodology can be extended to analyze other parameters.Originality/valueTo the best of the authors’ knowledge, this is the first report of a non-destructive evaluation of 3D-printed part quality using only in situ data in ME. The value is in improving part quality and reliability in ME, thereby reducing 3D printing part errors, plastic waste and the associated cost of time and material.

Indications for a genetic basis for big bacteria and description of the giant cable bacterium Candidatus Electrothrix gigas sp. nov.

Bacterial cells can vary greatly in size, from a few hundred nanometers to hundreds of micrometers in diameter. Filamentous cable bacteria also display substantial size differences, with filament diameters ranging from 0.4 to 8 µm. We analyzed the genomes of cable bacterium filaments from 11 coastal environments of which the resulting 23 new genomes represent 10 novel species-level clades of Candidatus Electrothrix and two clades that putatively represent novel genus-level diversity. Fluorescence in situ hybridization with a species-level probe showed that large-sized cable bacteria belong to a novel species with the proposed name Ca. Electrothrix gigas. Comparative genome analysis suggests genes that play a role in the construction or functioning of large cable bacteria cells: the genomes of Ca. Electrothrix gigas encode a novel actin-like protein as well as a species-specific gene cluster encoding four putative pilin proteins and a putative type II secretion platform protein, which are not present in other cable bacteria. The novel actin-like protein was also found in a number of other giant bacteria, suggesting there could be a genetic basis for large cell size. This actin-like protein (denoted big bacteria protein, Bbp) may have a function analogous to other actin proteins in cell structure or intracellular transport. We contend that Bbp may help overcome the challenges of diffusion limitation and/or morphological complexity presented by the large cells of Ca. Electrothrix gigas and other giant bacteria. IMPORTANCE In this study, we substantially expand the known diversity of marine cable bacteria and describe cable bacteria with a large diameter as a novel species with the proposed name Candidatus Electrothrix gigas. In the genomes of this species, we identified a gene that encodes a novel actin-like protein [denoted big bacteria protein (Bbp)]. The bbp gene was also found in a number of other giant bacteria, predominantly affiliated to Desulfobacterota and Gammaproteobacteria, indicating that there may be a genetic basis for large cell size. Thus far, mostly structural adaptations of giant bacteria, vacuoles, and other inclusions or organelles have been observed, which are employed to overcome nutrient diffusion limitation in their environment. In analogy to other actin proteins, Bbp could fulfill a structural role in the cell or potentially facilitate intracellular transport.

The Production of Ultra-Thin Polyethylene-Based Carbon Fibers out of an “Islands-in-the-Sea” (INS) Precursor

Carbon fibers (CF) and their composites (CC) are one of the world’s most promising and avant-garde high-performance materials, as they combine excellent mechanical characteristics with high weight reduction potential. Polyethylene (PE) is the perfect alternative precursor for CF as it combines widespread availability, low cost, high carbon content, and, most importantly, precursor fibers that can be produced via melt-spinning. PE-based CF production involves a challenging and time-consuming diffusion-limited chemical stabilization step. The work presented in this article tackles the challenge of reducing the chemical stabilization process time by converting a bicomponent island-in-the-sea fiber, consisting of PA6 as sea matrix and HDPE as island material, into an ultra-thin PE-precursor fiber. The produced precursor fiber is then successfully converted into an ultra-thin PE-based CF through sulfonation and subsequent carbonization in a continuous set-up. The resulting CF has a smooth surface with no observable surface defects and a filament diameter of around 3 µm. The successful conversion to ultra-thin CF is shown in both batch and continuous processes. Additionally, a reduction in sulfonation reaction time from 4 h to 3 h is achieved.

Determination of Energy Consumption During The Tensile Test Sample Production in 3D Printer Working with The Fused Deposition Modeling Method

Today, 3-dimensional (3D) printers are developing increasingly, and rapid progress is being made to become an alternative to traditional production methods. 3D printers, which produce with the Fused Deposition Modeling (FDM) method, commonly produce by using polymer materials in the form of filament with a diameter of 1.75 mm or 2.85 mm. This study, tensile test specimens were produced using PLA filaments of different diameters (1.75 mm and 2.85 mm) with two different 3D printers. The electricity consumption of 3D printers during the production of tensile test samples was measured. The energy consumed by both 3D printers in producing tensile test specimens was compared. Instead of simultaneously producing a single test sample, it has been determined that the power consumption per test sample will be reduced by producing many test samples together.

Accelerated in vitro oxidative degradation testing of polypropylene surgical mesh.

Polypropylene (PP) surgical mesh had reasonable success in repair of hernia and treatment of stress urinary incontinence (SUI); however, their use for the repair of pelvic organ prolapse (POP) resulted in highly variable results with lifelong complications in some patients. One of several factors that could be associated with mesh-related POP complications is changes in the properties of the implanted surgical mesh due to oxidative degradation of PP in vivo. Currently, there are no standardized in vitro bench testing methods available for assessing the susceptibility to oxidative degradation and estimating long-term in vivo stability of surgical mesh. In this work, we adapted a previously reported automated reactive accelerated aging (aRAA) system, which uses elevated temperatures and high concentrations of hydrogen peroxide (H2 O2 ), for accelerated bench-top oxidative degradation testing of PP surgical mesh. Since H2 O2 is highly unstable at elevated temperatures and for prolonged periods, the aRAA system involves a feedback loop based on electrochemical detection methods to maintain consistent H2 O2 concentration in test solutions. Four PP mesh samples with varying mesh knit designs, filament diameter, weight, and % porosity, were selected for testing using aRAA up to 4 weeks and characterized using thermal analysis, Fourier-transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) and scanning electron microscopy (SEM). Additionally, the oxidation index (OI) values were calculated based on the FTIR-ATR spectra to estimate the oxidative degradation and oxidation reaction kinetics of PP surgical mesh. The OI values and surface damage in the form of surface flaking, peeling, and formation of transverse cracks increased with aRAA aging time. The aRAA test method introduced here could be used to standardize the assessment of long-term stability of surgical mesh and may also be adopted for accelerated oxidative degradation testing of other polymer-based medical devices.

Sustainable fabrication of 3D printing filament from recycled PET plastic

The widespread use of plastic is leading to increased plastic waste and environmental concerns globally. This research paper aims to address this issue by investigating the potential of creating a sustainable 3D printing filament using recycled polyethylene terephthalate (PET) bottles. Our experimental setup involved a 1.6 mm diameter nozzle with a heater block to ensure precise temperature control during filament extrusion, resulting in a reliable and repeatable filament diameter of 1. 65 mm.The study focuses on creating a consistent filament with a 1.65 mm diameter using recycled PET bottles. Additionally, finite element analysis (FEA) is conducted using SolidWorks software to compare the mechanical properties of the PET filament to conventional polylactic acid (PLA) material widely used in 3D printing. The FEA simulations analyze stress, strain, and displacement for both PET and PLA materials, and the results are compared to draw conclusions based on the numerical observations. The findings from this research will offer valuable insights into the potential of recycled PET bottles as an environmentally friendly alternative for 3D printing filaments. This work contributes to reducing plastic waste and promotes sustainable practices in additivemanufacturing.

Investigating the thermal and mechanical properties of novel LDPE/TiO2 and LDPE/TiO2/CNT composites for 3D printing applications.

The development of new materials is essential for advancing technology and improving the quality of life. With new materials, we can create products that are stronger, more durable, and more efficient. The ongoing research and development of new materials for 3D printing applications continue to drive innovation in various fields, leading to improved products and processes with great benefits. The main goal of this work was to produce a functional filament with a 1.75-mm diameter that may be used for 3D printing. Composite materials were prepared using a low-density polyethylene (LDPE) resin as polymer matrix, and titanium dioxide (TiO2) and carbon nanotubes (CNT) as fillers in various ratios. Up to 15 wt% of TiO2 and 0.25 wt% of CNT were added. Some of the greatest difficulties with high filler content composites are achieving good homogeneity, and in the case of the 3D printing, greatest difficulties are producing the filament with a specific and stable filament diameter. During the 3D printing itself, the fillers can also often cause the nozzle clogging. This paper reports findings of thermal and mechanical properties of the LDPE/TiO2/CNT composites which are significant for the 3D printing process and the applicability of the composite materials. All of the planed composite materials are successfully prepared and 3D printed into the tensile test specimens. The melting point shift caused by the addition of fillers did not show consistent pattern at differential scanning calorimetry, as all of the samples had melting temperatures around 113.5 ± 1.4 °C. The addition of filler, according to the TGA, increased the threshold temperature for the material decomposition, in case of TiO2 5.4 °C increase, while TiO2 and CNT combination increased the threshold temperature for 6.8 °C. The results of the tensile test show a general increase trend with addition of TiO2 filler but do not show to a trend for the tensile strength as a result of the addition of CNT filler. The sample with highest TiO2 filler ratio of 15% (LDPE 15T0C) showed the greatest tensile strength of 14.5 MPa, compared to the 13.0 MPa of pure LDPE. The sample with 5% of TiO2 filler and 0.1% of CNT filler (LDPE 5T0.1C) showed the greatest elongation of 73.9%, compared to the 68.9% of pure LDPE.

Magnetization AC losses of MgB2 wires with thin filaments and resistive sheath

Magnetization AC losses of fine-filamentary MgB2 wires with resistive CuNi sheaths were measured. The effects of varying the number of filaments (114–342, corresponding to effective filament diameters of 14–20 μm), twist pitch (10–30 mm) and outer sheath material on the total AC loss were studied. For a better understanding of individual loss contributions, the effects of varying applied temperature, magnetic field, and frequencies were examined. It is found that hysteresis loss per volume decreases with the reduced filament size and that coupling current losses play a dominant role. The effect of decoupling by twisting was clearly observed for the smallest twist pitches. Considering the possible degradation of transport currents by twisting, AC losses were also normalized by the critical currents of the same wires. While twisting to short pitch decreases losses significantly, it apparently does not reduce the transport current. Consequently, the fine-filamentary MgB2 wires with resistive CuNi sheath examined in this paper are excellent candidates for future low loss applications. Unlike ReBCO tapes, round MgB2 wires enable easy single strand twisting, and the braiding or cabling, of wires into a variety of specific shapes and diameters.

Overview and Comparison of PLA Filaments Commercially Available in Europe for FFF Technology.

This study presents a comprehensive techno-economic analysis of PLA materials for fused filament fabrication (FFF) from eight European manufacturers. The comparison involved rigorous experimental assessments of the mechanical properties, dimensional accuracy, and print quality using standardized methods and equipment such as tensile and CT testing. What makes this study unique is the consistent methodology applied, considering factors such as material color, printing temperature, printing orientation, filament diameter, and printer selection, to ensure meaningful and reliable results. Contrary to the common belief that a higher price implies better quality, the study revealed that the second cheapest PLA material achieved the best overall performance within the methodology employed. The study also confirmed certain observations, such as the influence of printing orientation and geometry on dimensional accuracy and mechanical properties, as well as the significant disparities between manufacturer-provided values and actual measured mechanical properties, highlighting the importance of experimental verification. Hence, the findings of this study hold value not only for the scientific community but also for hobbyist printers and beginners in the 3D printing realm seeking guidance in material selection for their projects. Furthermore, the methodology employed in this research can be adapted for evaluating a broad range of other 3D printing materials.

Multilayer 3D bioprinting and complex mechanical properties of alginate-gelatin mesostructures

In the biomedical field, extrusion-based 3D bioprinting has emerged as a promising technique to fabricate tissue replacements. However, a main challenge is to find suitable bioinks and reproducible procedures that ensure good printability and generate final printed constructs with high shape fidelity, similarity to the designed model, and controllable mechanical properties. In this study, our main goal is to 3D print multilayered structures from alginate-gelatin (AG) hydrogels and to quantify their complex mechanical properties with particular focus on the effects of the extrusion process and geometrical parameters, i.e. different mesostructures and macroporosities. We first introduce a procedure including a pre-cooling step and optimized printing parameters to control and improve the printability of AG hydrogels based on rheological tests and printability studies. Through this procedure, we significantly improve the printability and flow stability of AG hydrogels and successfully fabricate well-defined constructs similar to our design models. Our subsequent complex mechanical analyses highlight that the extrusion process and the mesostructure, characterized by pore size, layer height and filament diameter, significantly change the complex mechanical response of printed constructs. The presented approach and the corresponding results have important implications for future 3D bioprinting applications when aiming to produce replacements with good structural integrity and defined mechanical properties similar to the native tissue, especially in soft tissue engineering. The approach is also applicable to the printing of gelatin-based hydrogels with different accompanying materials, concentrations, or cells.

Mesalazine hollow suppositories based on 3D printing for treatment of ulcerative colitis

Mesalazine (MSZ) suppositories are a first-line medication for the localized treatment of ulcerative colitis (UC). However, the frequent defecation of patients with UC influences the retention of the suppository in the rectum and multiple doses have to be applied. Here, a mesalazine hollow suppository (MHS) is developed using three-dimensional (3D) printing. The MHS is composed of an inner supporting spring and an outer MSZ-loaded curved hollow shell. Springs were prepared using fused deposition modeling (FDM) 3D printing with thermoplastic urethane filaments, followed by splitting. The optimal parameters, including elasticity, filament diameter, spring inner diameter, and filament distance, were screened. The shell was prepared by FDM 3D printing utilizing MSZ, polyvinyl alcohol, and polyethylene glycol, which were assembled with springs to obtain FDM 3D-printed MHS (F-MHS); if 3D-printed metal molding was used in preparing shell, mold-formed MHS (M-MHS) was obtained. The F-MHS exhibited faster MSZ release than the M-MHS; therefore, the molding method is preferable. The inserted M-MHS was retained in the rat rectum for 5 h without affecting defecation. M-MHS alleviated tissue damage of UC rats and reduced inflammation with low levels of myeloperoxidase and proinflammatory cytokines. Personalized MHS is a promising medication for the localized treatment of UC.

CREATING AN OPEN-SOURCE, LOW-COST COMPOSITE FEEDER DESIGN TO IMPROVE FILAMENT QUALITY OF HIGH-PERFORMANCE MATERIALS TO BE USED IN FUSED FILAMENT FABRICATION (FFF)

AbstractComposite filaments are getting increased attention in additive manufacturing (AM). More and better solutions for filament production are needed to assist researchers in discovering new materials capable of producing AM-made high-performance parts. This article presents a method for producing composite filament, including an open-source, low-cost automatic composite feeder designed to increase the accuracy and quality of the filament. The feeder includes a fibre screw designed through an iterative prototyping process to accurately control the filament's fibre percentage while reducing lumps' occurrence in a single step. An experiment evaluating the quality of filament made of Polylactic Acid (PLA) and carbon fibre (CF) tested the use of the feeder compared to manual mixing. Filament with a nominal diameter of 2.85mm with 4.5%, 7.9%, 11.2% and 14.5% CF was made. The results suggest that the composite feeder improved the filament quality. The filament diameter RMSE value was reduced from 0.08 to 0.06 and 0.15 to 0.13 for both 4.5% and 11.2%, respectively. The article concludes that the feeder design may help researchers develop and discover new materials while improving the quality of the filament.

Characterizing properties of scaffolds 3D printed with peptide-polymer conjugates

Three-dimensional (3D) printing is a popular biomaterials fabrication technique because it enables scaffold composition and architecture to be tuned for different applications. Modifying these properties can also alter mechanical properties, making it challenging to decouple biochemical and physical properties. In this study, inks containing peptide-poly(caprolactone) (PCL) conjugates were solvent-cast 3D printed to create peptide-functionalized scaffolds. We characterized how different concentrations of hyaluronic acid-binding (HAbind-PCL) or mineralizing (E3-PCL) conjugates influenced properties of the resulting 3D-printed constructs. The peptide sequences CGGGRYPISRPRKR (HAbind-PCL; positively charged) and CGGGAAAEEE (E3-PCL; negatively charged) enabled us to evaluate how conjugate chemistry, charge, and concentration affected 3D-printed architecture, conjugate location, and mechanical properties. For both HAbind-PCL and E3-PCL, conjugate addition did not affect ink viscosity, filament diameter, scaffold architecture, or scaffold compressive modulus. Increasing conjugate concentration in the ink prior to printing correlated with an increase in peptide concentration on the scaffold surface. Interestingly, conjugate type affected final conjugate location within the 3D-printed filament cross-section. HAbind-PCL conjugates remained within the filament bulk while E3-PCL conjugates were located closer to the filament surface. E3-PCL at all concentrations did not affect mechanical properties, but an intermediate HAbind-PCL concentration resulted in a moderate decrease in filament tensile modulus. These data suggest final conjugate location within the filament bulk may influence mechanical properties. However, no significant differences were observed between PCL filaments printed without conjugates and filaments printed with higher HAbind-PCL concentrations. These results demonstrate that this 3D printing platform can be used to functionalize the surface without significant changes to the physical properties of the scaffold. The downstream potential of this strategy will enable decoupling of biochemical and physical properties to fine-tune cellular responses and support functional tissue regeneration.

Effect of stearic acid on the mechanical and rheological properties of PLA/HA biocomposites

In this study, biocomposite filaments of polylactic acid (PLA) combined with stearic acid (SA)-coated nano-hydroxyapatite (HA) filler were prepared and characterized. These filaments were then used in material extrusion (MEX) additive manufacturing via fused deposition modeling (FDM) to create scaffolds for bone tissue engineering (BTE). Initially, HA was characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), and the Rietveld method. Particle size distribution was examined through dynamic light scattering (DLS), and its specific surface area was determined by the Brunauer-Emmett-Teller (BET) method. Subsequently, the HA nanoparticles were coated with stearic acid (SA) to explore its potential as a surfactant for PLA/HA nanocomposites. For composite fabrication, pure HA and SA-coated HA were mixed with PLA in a torque rheometer to obtain PLA/HA and PLA/HA-SA biocomposites. Their flow behavior was evaluated using a slit die rheometer, demonstrating that the SA coating improved rheological properties. The composites were extruded to produce 1.75 mm diameter filaments, which were analyzed by mechanical tensile testing, showing that the SA coating reduced the fragility of the PLA/HA filaments. The filaments exhibited high repeatability in terms of quality, facilitating scaffold printing. The FDM-manufactured scaffolds were analyzed through compressive testing, Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and AlamarBlue Cell Viability Analysis. The results demonstrated that these scaffolds possess the required mechanical, thermal, and cytotoxicity properties for applications in bone tissue engineering.

On the Thermomechanical Behavior of 3D-Printed Specimens of Shape Memory R-PETG.

From commercial pellets of recycled polyethylene terephthalate glycol (R-PETG), 1.75 mm diameter filaments for 3D printing were produced. By varying the filament's deposition direction between 10° and 40° to the transversal axis, parallelepiped specimens were fabricated by additive manufacturing. When bent at room temperature (RT), both the filaments and the 3D-printed specimens recovered their shape during heating, either without any constraint or while lifting a load over a certain distance. In this way, free-recovery and work-generating shape memory effects (SMEs) were developed. The former could be repeated without any visible fatigue marks for as much as 20 heating (to 90 °C)-RT cooling-bending cycles, while the latter enabled the lifting of loads over 50 times heavier than the active specimens. Tensile static failure tests revealed the superiority of the specimens printed at larger angles over those printed at 10°, since the specimens printed at 40° had tensile failure stresses and strains over 35 MPa and 8.5%, respectively. Scanning electron microscopy (SEM) fractographs displayed the structure of the successively deposited layers and a shredding tendency enhanced by the increase in the deposition angle. Differential scanning calorimetry (DSC) analysis enabled the identification of the glass transition between 67.5 and 77.3 °C, which might explain the occurrence of SMEs in both the filament and 3D-printed specimens. Dynamic mechanical analysis (DMA) emphasized a local increase in storage modulus of 0.87-1.66 GPa that occurred during heating, which might explain the development of work-generating SME in both filament and 3D-printed specimens. These properties recommend 3D-printed parts made of R-PETG as active elements in low-price lightweight actuators operating between RT and 63 °C.

3D graphene-based active electrodes with large areal capacitance by modified direct ink writing method

The application of 3D printing technology in the field of energy storage is of great practical significance but still remains challenging. Recently, 3D-printed graphene-based architecture has been found to be a promising material for electrochemical energy storage devices. In this study, graphene-based conductive filaments were printed through direct ink writing method (DIW), and then dense poly-pyrrole film (PPy) was formed on the surface of the 3D frame by simple electrodeposition. And followed by post treatment three-dimensional heterogeneous graphene-based electrodes wrapped by nanocarbon cloth (3DCGs) were readily prepared. 3D-printed open porous structure provides effective aligned channels for ion transport as well as large ion accessible area for electrochemical reaction. PPy layer helps to maintain the structural integrity and obtain high capacitance retention rate. A series of 3DCGs with controllable channels were prepared by adjusting the number printing layers, infilled spacing and nozzle size. Thus, we gained an insight into the influence of structural engineering of electrode materials on electrochemical performance. The 5-layer 3DCG with filament spacing of 300 µm and filament diameter of 400 µm achieved an areal capacitance of 2265.19 mF/cm2 at a scan rate of 5 mV/s, which was significantly higher than that of non-3DCG (400.15 mF/cm2). Briefly, this study reports the integration of DIW 3D-printing and electrodeposition techniques allowing a facile way of fabricating customized 3D-electrodes with large areal capacitance.

D65. Optimizing the Design of Biodegradable 3D-printed Scaffolds for Tissue Engineering Nipples with Lasting Projection and Biosimilar Stiffness

PURPOSE: Creating the nipple is the last surgical step of breast reconstruction. However, autologous tissue techniques are limited due to scar contracture and significant loss of neo-nipple projection. Poly-4-Hydroxybutyrate (P4HB) is a biodegradable polymer with a long track record of clinical use as a surgical mesh and we have previously shown long-term maintenance of nipple projection using 3D-printed P4HB nipple scaffolds filled with processed cartilage in nude rats. Here we aim to modify the interior reticular structure of the 3D-printed P4HB cylindrical scaffold to better mimic the biomechanical properties of the native nipple while maintaining the nipple projection in an immunocompetent rodent model. METHODS: Nipple scaffolds were 3D-P4HB printed (diameter: 1.0cm, height: 1.0cm) with different internal 3D latticework of P4HB filaments (infill density: 20, 25 and 30%; filament diameter: 0.15 and 0.2mm). All the scaffolds were subcutaneously implanted in rats using a CV flap technique. P4HB scaffolds without the internal latticework and Cook Biodesign® Nipple Cylinder were implanted as controls. RESULTS: The projection of 3D-P4HB nipples were well maintained over 3 months (>90%, p>0.05) and nipple stiffness slowly declined as the polymer was gradually replaced by tissue. In contrast, the Cook Biodesign® nipple lost 25% and 50% projection at 1- and 3-month respectively (p<0.05). CONCLUSION: We have successfully engineered neo-nipples that maintain projection over time, while simultaneously allowing for tissue ingrowth that is biomechanically similar to that of native nipples. Long-term observation will be warranted to verify the translatability of this novel 3D-P4HB nipple scaffold.

Three-dimensional orthogonal woven hybrid fabrics in X band frequency region for electromagnetic shielding effectiveness

The three-dimensional fabric structures with metallic yarns and different fibers offer additional opportunities to enhance the electromagnetic shielding potential. This study involves the manufacturing of a Three-Dimensional Orthogonal Woven (3DOW) hybrid conductive fabric to be potentially used in an electromagnetic shielding field. 3DOW fabric consisting of copper filament-based core-sheath hybrid yarn in the weft direction has been manufactured to obtain maximum shielding effect. Hybrid yarns were produced using the DREF-III spinning technique, having copper filament in the core and sheathing by Polyphenylene Sulfide (PPS) staple fibers. The experiment was designed using Box-Behnken method. The orthogonal fabric samples are tested in an electromagnetic frequency region of 8-12 GHz using Free Space Measurement System (FSMS) to estimate absorbance, reflectance, and transmittance. Hybrid yarn parameters such as PPS fiber diameter, copper filament diameter, and yarn linear density considerably affect electromagnetic shielding. 3DOW fabric’s electromagnetic shielding effect increase with the diameter of the copper core filament, as does PPS yarn’s diameter, showing a promising trend towards shielding. The findings of orthogonal structure can be further extended in other Three-Dimensional structures like multi-layer, angle interlock, draperies, and tops for civilians and soldierly applications.

Witnessing the fragmentation of a filament into prestellar cores in Orion B/NGC 2024

Context. Recent Herschel observations of nearby molecular clouds have shown that filamentary structures are ubiquitous and that most prestellar cores form in dense filaments. Probing the detailed density and velocity structure of molecular filaments is therefore crucial for improving our observational understanding of the star formation process. Aims. We aim to characterize both the density and the velocity field of a typical molecular filament in the process of fragmenting into cores. Methods. We mapped a portion of the NGC 2024 region in the Orion B molecular cloud with the Nobeyama 45m telescope, in the 12CO (J = 1–0), 13CO (J = 1–0), C18O (J = 1–0), and H13CO+ (J = 1–0) lines, and the southwestern part of NGC 2024, corresponding to the NGC 2024S filament, with the NOrthern Extended Millimeter Array (NOEMA) interferometer in H13CO+ (J = 1–0). Results. The maps of 13CO, C18O, and H13CO+ emission trace at least part of the filamentary structure seen in the 8″ resolution ArTéMiS+Herschel data. The median radial column density profile of the NGC 2024S filament as derived from ArTéMiS+Herschel dust emission data is well fitted by a Plummer profile with a half-power diameter DHPPlummer=0.081±0.014 pc, which is similar to the findings of previous studies of nearby molecular filaments with Herschel. On the other hand, the half-power diameters of NGC 2024S as measured from the Nobeyama 13CO and C18O data are broader than, and the half-power diameter derived from the H13CO+ data narrower than the filament diameter measured with Herschel. These results suggest that the 13CO and C18O data trace only the (low-density) outer part of the Herschel filament and the H13CO+ data only the (dense) inner part. We identify four cores in the portion of the Herschel map covered by NOEMA and find that each Herschel core corresponds to a single core detected in the combined NOEMA+45m H13CO+ data cube. The Nobeyama H13CO+ centroid velocity map reveals velocity gradients along both the major and the minor axis of the NGC 2024S filament, as well as velocity oscillations with a period λ ~0.2 pc along the major axis. Comparison between the centroid velocity and the column density distribution shows a tentative λ/4 phase shift in H13CO+ or C18O. This λ/4 shift is not simultaneously observed for all cores in any single tracer but is tentatively seen for each core in either H13CO+ or C18O. The difference between the H13CO+ and C18O velocity patterns may arise from differences in the range of densities probed by H13CO+ and C18O. We produced a toy model that takes into account the three velocity-field components: a transverse velocity gradient, a longitudinal velocity gradient, and a longitudinal oscillation mode caused by fragmentation. Examination of synthetic data shows that the longitudinal oscillation component produces an oscillation pattern in the velocity structure function of the model. Since the velocity structure function of the Nobeyama H13CO+ centroid velocity data does show an oscillation pattern, we suggest that our observations are partly tracing core-forming motions and the fragmentation of the NGC 2024S filament into cores. We also find that the mean core mass in NGC 2024S corresponds to the effective Bonnor-Ebert mass in the filament. This is consistent with a scenario in which higher-mass cores form in higher-line-mass filaments.

Influence of Scaffold Microarchitecture on Angiogenesis and Regulation of Cell Differentiation during the Early Phase of Bone Healing: A Transcriptomics and Histological Analysis.

The early phase of bone healing is a complex and poorly understood process. With additive manufacturing, we can generate a specific and customizable library of bone substitutes to explore this phase. In this study, we produced tricalcium phosphate-based scaffolds with microarchitectures composed of filaments of 0.50 mm in diameter, named Fil050G, and 1.25 mm named Fil125G, respectively. The implants were removed after only 10 days in vivo followed by RNA sequencing (RNAseq) and histological analysis. RNAseq results revealed upregulation of adaptive immune response, regulation of cell adhesion, and cell migration-related genes in both of our two constructs. However, significant overexpression of genes linked to angiogenesis, regulation of cell differentiation, ossification, and bone development was observed solely in Fil050G scaffolds. Moreover, quantitative immunohistochemistry of structures positive for laminin revealed a significantly higher number of blood vessels in Fil050G samples. Furthermore, µCT detected a higher amount of mineralized tissue in Fil050G samples suggesting a superior osteoconductive potential. Hence, different filament diameters and distances in bone substitutes significantly influence angiogenesis and regulation of cell differentiation involved in the early phase of bone regeneration, which precedes osteoconductivity and bony bridging seen in later phases and as consequence, impacts the overall clinical outcome.