Flat Orientation Research Articles

Optimized Protocol for Intestinal Swiss Rolls and Immunofluorescent Staining of Paraffin Embedded Tissue.

The intestine is a complex organ composed of the small and the large intestines. The small intestine can be further divided into duodenum, jejunum, and ileum. Each anatomical region of the intestine has a unique function that is reflected by differences in cellular structure. Investigating changes in the intestine requires an in-depth analysis of different tissue regions and cellular alterations. To study the intestine and visualize large pieces of tissue, researchers commonly use a technique known as intestinal Swiss rolls. In this technique, the intestine is divided into each anatomical region and fixed in a flat orientation. Then, the tissue is carefully rolled and processed for paraffin embedding. Proper tissue fixation and orientation is an often-overlooked laboratory technique but is critically important for downstream analysis. Additionally, improper Swiss rolling of intestinal tissue can damage the fragile intestinal epithelium, leading to poor tissue quality for immunostaining. Ensuring well-fixed and properly oriented tissue with intact cellular structures is a crucial step that ensures optimal visualization of intestinal cells. We present a cost-effective and simple method for making Swiss rolls to include all sections of the intestine in a single paraffin-embedded block. We also describe optimized immunofluorescence staining of intestinal tissue to study various aspects of the intestinal epithelium. The following protocol provides researchers with a comprehensive guide to obtaining high-quality immunofluorescence images through intestinal tissue fixation, Swiss-roll technique, and immunostaining. Employing these refined approaches preserves the intricate morphology of the intestinal epithelium and fosters a deeper understanding of intestinal physiology and pathobiology.

Build and raster orientation effects on CFRP onyx/aramid impact absorption

Composite materials fabricated via additive manufacturing are becoming more relevant in ready-for use products used in engineering applications like aerospace structures, propellers, electric vehicles, or sandwich cores. Continuous Fiber Reinforced Polymeric (CFRP) composites are 3D-printed composites with tailor-made properties due to the capability of the printing process to deposit matrix and fiber whenever required. However, CFRP products behave differently and have lower mechanical properties than traditional composites. This study aimed to analyze the impact strength of CFRP specimens with gyroid infill and the effects of two build (flat and on-edge) and two raster (0° and 45°) orientations on impact behavior. The gyroid infill helps to obtain a light-weight structure and it has been used in energy absorption applications showing excellent mechanical behavior in thermoplastic 3D-products. The specimens were manufactured using Onyx as the matrix and aramid fiber as the reinforcement materials. The impact energy absorption of CFRP composites was measured using unnotched Izod impact specimens. The impact tests results were statistically analyzed, revealing that the build orientation directly and significantly affects the impact behavior, resulting in higher impact absorption when flat orientation is used to produce CFRP composites. The impact strength of CFRP composites increased 8 times, and 2 times for flat and on-edge oriented specimens, respectively compared to pure Onyx specimens. The variation in impact energy absorption between raster orientations in both build orientations was not significant, the difference in flat-oriented specimens at 0° and 45° was only 0.2 J, and between on-edge-oriented specimens at 0° and 45° was only 0.089 J. Also, the after impact specimens were analyzed to categorize the different failure modes observed. The after-impact analysis showed poor impregnation between aramid and onyx layers, causing delamination, fiber bridging, and fiber exposure failures. The combination of Aramid, Onyx, and a non-solid infill (gyroid) demonstrated positive results in impact behavior, obtaining high-impact absorption (165 kJ/m2) with no more than 56 % of fiver volume. The impact properties information of CFRP composites made with aramid fibers is still very scarce, joined to the lack of information on the impact properties of CFRP composites with non-solid infill, like gyroids or sinusoidal path infills. The results of this research open the possibility of using non-solid infill in CFR process that can be used to manufacture and test ready-for-use CFRP products in tasks that require high-strength, low-weight structures and impact energy absorption.

Using extrusion-based 3D printing technology to investigate the impact of changing print conditions on tensile characteristics

PurposeThe purpose of this study, most recent advancements in threedimensional (3D) printing have focused on the fabrication of components. It is typical to use different print settings, such as raster angle, infill and orientation to improve the 3D component qualities while fabricating the sample using a 3D printer. However, the influence of these factors on the characteristics of the 3D parts has not been well explored. Owing to the effect of the different print parameters in fused deposition modeling (FDM) technology, it is necessary to evaluate the strength of the parts manufactured using 3D printing technology.Design/methodology/approachIn this study, the effect of three print parameters − raster angle, build orientation and infill − on the tensile characteristics of 3D-printed components made of three distinct materials − acrylonitrile styrene acrylate (ASA), polycarbonate ABS (PC-ABS) and ULTEM-9085 − was investigated. A variety of test items were created using a commercially accessible 3D printer in various configurations, including raster angle (0°, 45°), (0°, 90°), (45°, −45°), (45°, 90°), infill density (solid, sparse, sparse double dense) and orientation (flat, on-edge).FindingsThe outcome shows that variations in tensile strength and force are brought on by the effects of various printing conditions. In all possible combinations of the print settings, ULTEM 9085 material has a higher tensile strength than ASA and PC-ABS materials. ULTEM 9085 material’s on-edge orientation, sparse infill, and raster angle of (0°, −45°) resulted in the greatest overall tensile strength of 73.72 MPa. The highest load-bearing strength of ULTEM material was attained with the same procedure, measuring at 2,932 N. The tensile strength of the materials is higher in the on-edge orientation than in the flat orientation. The tensile strength of all three materials is highest for solid infill with a flat orientation and a raster angle of (45°, −45°). All three materials show higher tensile strength with a raster angle of (45°, −45°) compared to other angles. The sparse double-dense material promotes stronger tensile properties than sparse infill. Thus, the strength of additive components is influenced by the combination of selected print parameters. As a result, these factors interact with one another to produce a high-quality product.Originality/valueThe outcomes of this study can serve as a reference point for researchers, manufacturers and users of 3D-printed polymer material (PC-ABS, ASA, ULTEM 9085) components seeking to optimize FDM printing parameters for tensile strength and/or identify materials suitable for intended tensile characteristics.

Prediction of Optimal Parameter Settings and Significant Parameter for Reduced Geometric Deviations Through Multi Criteria Decision Making and Machine Learning Algorithms

Part dimensional inaccuracies serve as a barrier from adopting Additive Manufacturing (AM) processes in mass production. Fused Deposition Modeling (FDM) is a thermoplastic based low cost AM process which can create conceptual models, prototypes and end user industrial parts. The current study involves predicting the optimal parameter settings and significant parameter for reduced geometric deviations in printed part using Nylon filament reinforced with 20% carbon fiber. Five input factors such as build orientation, layer thickness, infill density, raster angle and infill pattern have been considered for preparing the experimental layout through taguchi�s mixed fractional factorial design. The changes in length, width and thickness of the printed part from CAD value have been evaluated individually through ANOVA and Signal to Noise Ratio method (Smaller the better). Layer thickness is significant only for variations in length, but build orientation affects both width and thickness dimensions. The geometric deviations are further analyzed using combined multi criteria decision making (MCDM) approaches such as Entropy-CoCoSo and PCA-TOPSIS. The optimal parameter settings obtained for reduced geometric deviations is found to be Flat orientation, 0.1mm layer thickness, 50% infill density, 0� raster angle and cubic infill pattern. Layer thickness is found to be highly significant parameter influencing the geometric deviations subsequently followed by build orientation from both the MCDM methods. The multi response performance index values obtained from Entropy-CoCoSo has been trained using classification algorithms such as decision tree, random forest and Naive Bayes. Naive Bayes algorithm outperformed other methods with highest classification accuracy of 99.4% in a training-testing split ratio of 75:25.

Tensile Test Analysis of 3D Printed Specimens with Varying Print Orientation and Infill Density

The research conducted aimed to investigate the effect of varying print orientation and infill density on the mechanical properties of different 3D printed polymer specimens by conducting tensile tests. The Stratasys Fortus 900mc Material Extrusion printer was used to produce multiple samples of different materials, namely, Acrylonitrile Styrene Acrylate (ASA), Nylon 12, Nylon 12 Carbon Fibre, ULTEM 1010, and ULTEM 9085 which were subjected to tensile tests according to the ASTM D638 standard. Samples were printed in flat, side, and upright orientations with both sparse (50%) and solid (100%) infill densities. The samples were then tensile tested to obtain the Young’s Modulus, ultimate tensile strength (UTS), yield strength, and strain at break. The results produced revealed that the solid infill specimens almost always outperformed the sparse infill specimens. In terms of print orientation, side-orientated specimens achieved higher values for the material properties, followed by the flat specimens, with the upright specimens producing the performance with the lowest values. There were, however, notable exceptions to the results trends mentioned above. These findings were analysed using fracture mechanics and composite theory to explain the unexpected behaviour.

A theoretical approach to the corrosion inhibition of iron in acidic solution by a green formulation derived from Nigella sativa L seeds oil

A theoretical approach combining density functional theory (DFT) computation, Monte Carlo (MC) methods, and molecular dynamics (MD) simulations was used to investigate and validate the iron corrosion inhibition performances in the acidic medium of a green formulation based on the oil extracted from Nigella sativa L. DFT calculations allowed to determine the energetic, global, and local chemical reactivity parameters. The most stable adsorption configuration of the fatty acids components of the Nigella sativa L. formulation was determined by the Monte Carlo methods with the adsorption locator module and by molecular dynamics simulations. Results indicated that all the compounds are absorbed with a totally flat orientation on the first layer of the metal surface.The active sites of molecules were effectively established by using DFT through the analysis of frontier molecular orbitals (FMO), the Hirshfeld population analysis (HPA), the electrostatic potential (ESP), molecular electron density analysis (MED), and Fukui indices (FI). The solvent effect was investigated by using the conductor-like polarizable continuum model (CPCM). Protonation effects were also analysed through the protonation energy (PE), the proton affinity (PA), and the absolute gas phase basicity (GB). The formation of a coating on the iron surface validated the good protective action of the green formulation derived from Nigella sativa L.The computational and theoretical approaches substantiate our experimental electrochemical and spectroscopic studies [1].

Influence of build orientation on porosity, strength and dimensional accuracy of laser sintered polyamide porous bone scaffolds

Development of synthetic bone graft via bone tissue engineering involves seeding of patient’s stem cells onto a porous scaffold in presence of growth factors. Porosity, strength and dimensional accuracy of the porous scaffold play a vital role in this process. This work aims at ascertaining influence of build orientation on porosity, mechanical strength and dimensional accuracy of the selectively laser sintered polyamide porous scaffolds. Initially, CAD models of test specimens with pre-designed porosity were created in Solidworks® software. All the specimens were fabricated on EOSINT P395, a selective laser sintering machine, along various primary (Flat, Edge, Upright and Flat_diag) and secondary (0o, 30o, 45o, 60o and 90o) orientations. Results show that measured porosity of most of the specimens was (range: 42.89-35.26%) less than the designed porosity (41.71%). Maximum average tensile strength (16.84 MPa) was recorded for specimens printed along Flat_0o orientation. Specimens printed along Upright_90o orientation showed highest average compressive strength (8.26 MPa). Specimens printed along Flat orientation showed relatively better average impact strength. Best dimensional accuracy was obtained for specimens printed along Flat orientation.

Molecular mechanism of decoupling between the fluorescence anisotropy thermograms of diphenylhexatriene and the thermotropic phase transitions of biomimetic ion pair amphiphile bilayers

The fluorescence anisotropy (FA) thermogram is a common technique to characterize the thermotropic phase properties and to determine the phase transition temperature of a lipid bilayer. For several biomimetic bilayer systems composed of ion pair amphiphiles (IPAs), however, the FA thermograms obtained with the 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescent probe fail to capture their phase transition behaviors. Here, we employed molecular dynamics (MD) simulation to examine the dynamics of common fluorescent probes, including DPH and 1-[4-(trimethylamino)phenyl]-6-phenyl-1,3,5-hexatriene (TMA-DPH), and evaluated the corresponding FA signals from the probe's rotational autocorrelation functions. The resulting FA thermogram of DPH in a DPPC bilayer indeed exhibits a sigmoidal feature that correlates with the phase behavior for the membrane. In contrast, the DPH FA thermogram fails to reflect the phase transition of IPA membranes with asymmetric or short alkyl tails. Such decoupling phenomenon is attributed to (1) the inherently disordered chain packing within the IPA bilayers of short alkyl tails, or (2) the flat orientation of DPH within the IPA bilayers featuring asymmetric alkyl chains. The FA thermograms further reweighted by the ratio of DPH flat orientation in IPA bilayers show excellent agreements with experimental data, demonstrating the importance of DPH orientation. Conversely, the amphiphilic TMA-DPH can capture the structural changes near the bilayer surface during the phase transition, applicable for a variety of IPA systems. The combined results provide important insights into the phase transition behaviors of different bilayer systems and offer guidance for probe selection in FA studies.

4D Printing of Commercial based Conductive Polylactic Acid: Strength and Resistance Properties

Four-dimensional (4D) printing technology is an innovative concept integrating conventional 3D printing additive manufacturing (AM) and smart materials programed to change properties or shape over time in response to environmental stimuli. This study aims to characterize the strength and electrical resistance of a commercial electrically conductive polylactic acid (PLA) with carbon black (CB) particles printed by fused filament fabrication (FFF) technique to evaluate the development feasibility of two sensor prototypes: (1) a load-cell sensor, and (2) a temperature sensor. Experiments were performed to study the orientation and raster angle–dependent mechanical and electrical performance of a PLA-CB conductive polymer manufactured by AM-FFF technology. A good agreement was observed between the data received from the manufacturer and the experimental density of the conductive AM-FFF PLA-CB three-point bending samples. The mechanical properties of 3D-printed PLA-CB were characterized based on three-point bending flexural test. Two build orientations (flat and upright) and three raster patterns (0°/90°, +45°/-45°, and concentric) were printed to check the optimal mechanical properties for electrical conductivity; six samples were printed for each one of the six configurations. The three-point bending flexural test results of the examined 36 specimens demonstrated that the samples printed in the concentric and +45°/-45° raster patterns exhibit the best mechanical properties, with the highest flexural strength and flexural modulus of elasticity in the flat orientation. Nevertheless, the concentric pattern has an advantage over the +45°/-45° pattern due to higher density and homogeneity. To examine the electrical resistance of the PLA-CB material another 12 specimens were printed and divided into four groups, each with different lengths. The electrical intrinsic resistivity was calculated from the geometry of the specimens and the measured resistance, with an average value of 13.2 [Ω·cm]. To check the production feasibility of a load-cell sensor prototype the effect of load on electrical conductivity was examined, however no effect of load on resistance was discovered. To prove the production feasibility of a sensor prototype for temperature measurements a preliminary device was designed and the effect of increasing and decreasing the temperature between 24 and 42°C on electrical resistance was examined. Based on the experimental results a calibration function was built linking between the temperature and the material’s resistance.

The Effect of Size on the Mechanical Properties of 3D-Printed Polymers

Most of the experiments on additively manufactured polymers are on a small scale, and it remains uncertain whether findings at a small scale can be extrapolated to their larger-scale counterparts. This uncertainty mainly arises due to the limited studies on the effect of size on three-dimensional (3D)-printed polymers, among many others. Given this background, this preliminary study aims to investigate the effect of geometric dimensions (i.e., the size effect) on the mechanical performance of four representative types of 3D-printable polymers, namely, (1) polycarbonate acrylonitrile butadiene styrene (PC/ABS), (2) acrylonitrile-styrene-acrylate (ASA), (3) polylactic acid (PLA) as a bio biodegradable and sustainable material, and (4) polyamide (PA, nylon), based on compression, modulus of elasticity, tension, and flexural tests. Eight different sizes were investigated for compression, modulus of elasticity, and tension tests, while seven different sizes were tested under flexure as per relevant test standards. A material extrusion technique was used to 3D-print the polymers in a flat build orientation and at an infill orientation angle of 45°. The results have shown that the mechanical properties of the 3D-printed polymers were size-dependent, regardless of the material type, with the most significant being flexure, followed by tension, compression, and modulus of elasticity; however, no clear general trend could be identified in this regard. All the materials except for nylon showed a brittle failure pattern, characterized by interfacial failure rather than filament failure. PLA outperformed the other three polymer specimens in terms of strength, irrespective of the type of loading.

Integrating experimental and theoretical studies in the development of a novel alginate-based bio-composite for copper anticorrosion in 3.5 % NaCl environments

The development of new coatings based on a biopolymer, epichlorohydrin-modified alginate, and alginate-epichlorohydrin-SrTiO3 nanocomposites incorporating SrTiO3 (STO) nanoparticles in the alginate (Alg) matrix (Alg-Ep-STO), has been addressed in this study. Various characterization techniques were employed to analyze the prepared compounds, including X-ray diffraction spectroscopy (XRD), Fourier-transform infrared spectroscopy (FTIR), as well as surface analysis methods such as Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX). Furthermore, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarisation (PDP) methods were used to evaluate corrosion inhibition and protection durability. The results demonstrate that the incorporation of STO nanoparticles into the alginate matrix with epichlorohydrin significantly improved the metal's resistance to corrosion. The experimental findings received reinforcement from various computational methods, including density functional theory (DFT), Molecular Dynamics (MD) and Monte Carlo (MC) simulations, which were employed to investigate the interactions between the Alg-Ep-STO nanocomposite and the copper surface. The computational outcomes revealed that the Alg-Ep-STO nanocomposite exhibits robust adhesion to the copper surface, maintaining a flat orientation, with its alignment being notably influenced by the presence of STO nanoparticles.

Molecular structure impacts of tetrazole derivatives on their diffusion and adsorption behaviors for microvia copper void-free filling

Optimizing a high-quality leveler has become the core task in developing the microvia copper filling technology. In this work, two nitrogen-containing heterocyclic compounds, iodonitrotetrazolium chloride (INT) and thiazolyl blue tetrazolium bromide (MTT) with a similar tetrazolyl group are selected as the levelers to investigated the molecular structure impacts on their microvia copper filling performance. Both INT and MTT inhibit the electroreduction of copper ions. The inhibiting effect of INT is greatly enhanced by convection while MTT is independent of convection, indicating a bottom-up filling performance of INT and a conformal filling performance of MTT. The microvias are supper-filled and poor-filled in electrolytes containing INT and MTT, respectively, as predicted by electrochemical analysis. Molecular dynamic simulation demonstrates that INT adsorbs in a flat orientation with its iodine and nitro group's two oxygen atoms interacting on the Cu(111) plane surface. MTT adsorbs on Cu(111) surface via positively charged tetrazole ring and its adsorption ability is much stronger than that of INT. The weak adsorption ability of INT on copper surface and the slow mass transfer rate result in its convection-dependent adsorption behavior and the excellent microvia copper filling performance.

A convenient and user-friendly hydrometallurgical process for preparing porous siliceous adsorbents using ascharite tailings: Mechanism of structural change and evaluation of adsorption properties

Ascharite tailings are discarded by the boron industry due to their low boron content and high magnesium content. Additionally, the large-scale storage of these tailings contributes to resource wastage and environmental pollution. The present study successfully prepared a siliceous adsorbent through the combined use of mechanical and acid activation methods. The tailings underwent acid treatment under mild conditions, leading to the dissolution of magnesium while maintaining the integrity of the silicate framework. This process resulted in the formation of a mesoporous structure primarily composed of slit-shaped pores. The specific surface area reached 234.7 m2 g−1, while the pore volume reached 0.31 cm3 g−1. The maximum adsorption capacity for methylene blue was 0.66 mg m−2 per unit of surface area. The pollutants displayed a flat orientation at equilibrium, with a maximum tilt angle of approximately 53°. The adsorption rate was limited due to the decrease in available adsorption sites. However, mechanical activation increased the density of active silanol sites from 2.76 to 4.34 mg m−2, significantly weakening the shielding effect on other potential sites. Thus, tailings resources can be effectively converted into valuable adsorbent materials using a convenient and controllable hydrometallurgical process.

Surface Roughness in Metal Material Extrusion 3D Printing: The Influence of Printing Orientation and the Development of a Predictive Model

This study investigates the influence of printing orientation on the surface roughness in metal material extrusion 3D printing of 17-4 PH stainless steel. Experimental tests were conducted on the Markforged Metal X commercial 3D printer at Vinh Long University of Technology Education, Vietnam. The samples were printed in three different orientations: flat, on-edge, and upright. Surface roughness measurements were performed using a handheld Mitutoyo SJ-210 roughness tester. Quantitative analysis of the surface roughness measurements revealed significant variations among the different printing orientations. The upright orientation exhibited the smoothest surface, with an average Ra value of 7.42 μm and Rz value of 40.49 μm. In contrast, the flat orientation showed the highest roughness, with an average Ra value of 82.83 μm and Rz value of 109.32 μm. The on-edge orientation had intermediate roughness values, with an average Ra value of 69.42 μm and Rz value of 92.17 μm. The study also introduces a novel predictive model for surface roughness based on the printing parameters. The model demonstrated accurate estimations for surface roughness values in specific cases, enabling optimization of the printing process for desired surface quality.

Experimental Investigation to Optimize Build Orientation and Raster Angle for PLA and ABS Specimens Generated by FDM Technology

The fused deposition modeling (FDM) process is used increasingly in the manufacture of mechanical parts and more particularly in the automotive and aeronautical fields. The purpose of this work is to optimize build orientation for obtaining polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS) samples with the best mechanical properties, dimensional accuracy, surface quality, and minimal total cost. For achieving This, PLA and ABS specimens are fabricated by FDM technology with three build orientations (flat, on edge, upright) and three raster angles (0°, 45°, 90°).at first, the dimensions of the produced samples are measured .secondly, the tensile test, DETLAB equipment was used to obtain tensile stress. In addition, roughness testers were also used to measure surface quality. As a consequence, the findings indicate that the mechanical strength increases with decreasing raster angle and by aligning from upright to flat orientation for both materials due to the fracture mechanism and loading direction. Also, the manufacturing orientation and raster angles significantly affected the dimensional accuracy and total cost. Additionally, there was a big difference in the surface roughness depending on the manufacturing orientation and raster angle; perpendicular measurements increase surface roughness values. We aim to investigate the impact of flat, on-edge, and upright build orientations as well as raster angles on the total cost, tensile strength, dimensional accuracy, and surface roughness of PLA and ABS material through tensile experiments.

Effects of copper additives on load carrying capacity and micro mechanisms of fracture in 3D-printed PLA specimens

This study deals with the effects of employing copper additives on the fracture resistance and fracture micro-mechanisms of 3D-printed Polylactic Acid (PLA) specimens under mixed mode I/II loading. Several comparative fracture tests are conducted on pre-cracked Semi-Circular Bend (SCB) specimens made of pure PLA and particulate copper-reinforced PLA (PLA/Cu) printed using the Fused Deposition Modeling (FDM) technique. The SCB specimens are fabricated in three different layer orientations. The comparison of the experimental results reveals that employing copper additives increases the load carrying capacities (LCCs) of the pre-cracked SCB specimens with the flat, on-edge, and upright layer orientations by 2.9%, 15.5%, and 27.7%, respectively. In addition, to determine the tensile properties of two desired materials, dogbone specimens made of PLA and PLA/Cu in three different layer orientations are fabricated and tested. The experimental results obtained from the characterization tests similarly indicate that the presence of copper additives in 3D printed PLA specimens increases ultimate tensile strength by 15.9%, 14%, and, 10.4% in the three flat, on-edge, and upright layer orientations, respectively. Aside from performing experimental tests, the LCCs of pre-cracked specimens are predicted theoretically by utilizing Equivalent Material Concept (EMC) combined with the well-known Average Strain Energy Density (ASED) criterion. It is shown that the EMC-ASED criterion can estimate accurately the experimental LCCs of both FDM-PLA and FDM-PLA/Cu specimens. Finally, the Scanning Electron Microscope (SEM) technique is employed to provide a better understanding of the effects of copper additives on the micro-mechanisms of fracture.

Effect of Different Standard Geometry Shapes on the Tensile Properties of 3D-Printed Polymer.

This study presents a comparative analysis of the tensile properties of 3D-printed polymer specimens with different standard geometry shapes. The objective is to assess the influence of printing orientation and geometry on the mechanical performance. Rectangular-shaped ASTM D3039 specimens with angles of 0°, 15°, and 90° are compared to various tensile test specimens based on ASTM and ISO standards. All specimens are fabricated using polyethylene terephthalate glycol (PETG) material through fused deposition modeling (FDM). Two printing orientations, flat and on-edge, are investigated, and tensile strength, elastic modulus, strain, and elongation at break are measured. The study examines the weak spot commonly found at the neck of the specimens and evaluates the broken areas. Additionally, a numerical analysis using the finite element method (FEM) is performed to identify stress risers' locations in each specimen type. Experimental results show that the ASTM D3039-0° specimen printed in the on-edge orientation exhibits the highest tensile properties, while the flat orientation yields the best results in terms of the broken area. The ISO 527-2 specimens consistently display lower tensile properties, irrespective of the printing orientation. The study highlights the enhanced tensile properties achieved with the rectangular shape. Specifically, the tensile strength of ASTM D3039-0° was 17.87% and 21% higher than that of the ISO 527 geometry shape for the flat and on-edge orientations, respectively. The numerical analysis indicated that the ISO 527-2 specimen had either no or minimal stress raisers, and the higher stresses observed in the narrow section were isolated from the gripping location. The findings contribute to understanding the relationship between standard geometry shapes, printing orientation, and the resulting tensile properties of 3D-printed polymer specimens.

The Effect of Infill Angle and Build Orientation on the Impact Strength and Production Time of Porous Infill Structure

In developing a lightweight structure, the density of the structure can be reduced by converting a solid structure to a porous infill structure. Previous research has investigated that a triangular infill structure has the highest impact strength compared to other infill patterns. However, the impact strength of this structure may still be improved by adjusting other parameters without extending the production time. This research goal is to investigate the effect of the build orientation and infill angle on the impact strength and the production time of the triangular infill structure. To achieve that goal, this research uses a 3D printing process to manufacture a triangular infill structure made of Polylactic Acid. Seven levels of infill angle and two levels of build orientation are used to find the effect. In this experiment, twenty-six Charpy Impact specimens are printed using the Fused Deposition Modelling machine. Each specimen is printed according to ISO 179 standards and tested using a GT-7045 impact testing machine to measure the impact strength of the specimen. The results of this experiment indicate that the resistance of the on-edge build orientation to the impact load is better than the flat build orientation. The on-edge build orientation type requires less printing time compared to the flat build orientation type for each infill angle. The use of a 45-degree infill angle exhibits the highest impact resistance. To achieve the shortest printing time, the 0-degree infill angle is recommended.

Adsorption of Tannic Acid onto Gold Surfaces

Thin film coatings are widely applicable in materials for consumer products, electronics, optical coatings, and even biomedical applications. Wet coating can be an effective method to obtain thin films of functional materials, and this technique has recently been studied in depth for the formation of bioinspired polyphenolic films. Naturally occurring polyphenols such as tannic acid (TA) have garnered interest due to their roles in biological processes and their applicability as antioxidants, antibacterial agents, and corrosion inhibitors. Understanding the adsorption of polyphenols to surfaces is a core aspect in the fabrication processes of thin films of these materials. In this work, the adsorption of TA to gold surfaces is measured using a quartz crystal microbalance with dissipation monitoring (QCMD) and surface plasmon resonance (SPR) for a wide range of TA concentrations. The adsorption kinetics, aggregation, and stability of TA solutions in physiological-like conditions are studied. Unexpectedly, it is found that the adsorption rates depend only weakly on concentration because of the presence of TA aggregates that do not adsorb. The mechanism of layer formation is also investigated, finding that TA monolayers readily adsorb onto gold with flat or edge-on molecular orientations dependent on the solution concentration. A mix of orientations in the intermediate case leads to slow multilayer adsorption.

Effect of building orientation and fibre type on the mechanical behaviour of additively manufactured ABS matrix composites

ABSTRACT Additive manufacturing of fibre-reinforced composites show high potential for fabrication of next-generation lightweight complex structural parts. In this study, the effects of building orientation and fibre type, i.e. carbon fibre (CF), and glass fibre (GF), on the mechanical properties of acrylonitrile butadiene styrene (ABS) composites fabricated by fused deposition modelling (FDM) were investigated. The mechanical properties, namely, tensile strength, elastic modulus, hardness, and toughness, were analyzed for flat, on-edge, and upright building orientations. Results revealed that building orientation significantly influences several mechanical properties; in-plane (flat and on-edge) orientations produced the best mechanical properties, whereas upright orientations produced the worst. However, building orientation had little effect on material hardness. Further, compared to the elastic modulus and tensile strength of pure ABS, those of CF-reinforced ABS (CF–ABS) increased by 800% and 500%, respectively, and those of GF-reinforced ABS (GF–ABS) increased by 400% and 400%, respectively, proving that reinforcing ABS with either CF or GF improves the tensile properties. The impact energy of CF–ABS (0.5 J) was lower than that of GF–ABS (1.1 J) because of the brittleness of CF. Fracture surface analysis was performed via scanning electron microscopy (SEM) which gave insight to the nature and mode of fracture of the failed specimens. The most common defects on the printed specimens were void formation, fibre pullout, and poor bonding between fibre and matrix.