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This paper investigates the tensile properties of jute-reinforced composites fabricated using stereolithography (SLA) 3D printing. Tensile tests were conducted using dog-bone tensile specimens following ASTM D638 Type IV specifications. Additionally, the study explores the effect of layer thickness on the tensile properties of the 3D-printed composite material, examining four different layer thicknesses: 0.025 mm, 0.05 mm, 0.075 mm, and 0.1 mm. The findings revealed that the tensile strength of the 3D-printed jute-reinforced composites increased with the printing layer thickness, reaching its maximum at a layer thickness of 0.1 mm. This represents an enhancement of approximately 84% compared to pure resin. Examination of the fiber–matrix interface under an optical microscope revealed a wavy pattern, suggesting that the interface may act as a mechanical interlock under tensile loads, thereby significantly enhancing tensile strength. The strength of the 3D-printed jute-reinforced composites was found to be comparable to that of glass fiber mat epoxy composites. This demonstrates that 3D SLA-printed jute-reinforced composites offer a promising avenue for producing next-generation composites that are typically challenging to manufacture using traditional fabrication techniques. [ABSTRACT FROM AUTHOR]

Hand lay-up was used to create banana and nylon Fibre-reinforced vinyl ester (VE) composites with random orientation of the short fibre ratio (banana:nylon = 1:1). To make it environmentally conscious, natural fibre (banana) was added in synthetic fibre (nylon). After fabrication, different mechanical testing was conducted. Tensile strength improves by 47% at 10 wt. % fibre loading and 13% at 20 wt.% fibre loading. Flexural strength improved by up to 213% at 15 wt. % fibre loading. At 20 wt. % fibre loading, the mean hardness number reaches its maximum. The mean impact energy is highest at 15 wt. % fibre loading. Furthermore, the highest water absorption is 2.3% with a fibre loading of 20 wt.%. After 15 wt.% fibre loading, which is suggested for optimal performance, the manufactured composites exhibit a declining trend in tensile, flexural, and impact capabilities. As a result, scanning electron micrographs were collected at 20 wt.% fibre loading to investigate the type of fibre-matrix bonding, voids, fibre agglomeration, and fibre pullouts phenomena. Fourier Transform Infrared spectroscopy was also explored to show a decline in hemicelluloses content. As-fabricated composites have several technological uses, including leisure and sports products, maritime sectors, and airplanes. [ABSTRACT FROM AUTHOR]

The growing interest in sustainable and biodegradable materials has prompted significant attention towards natural fiber-reinforced composites (FRC) due to their lower environmental impacts. In a similar sustainable vein, this study fabricated composite materials utilizing bagasse fibers with the 3D SLA (Stereolithography) printing method. To start with, a novel fiber extraction process was adopted for extracting fiber from the bagasse stem in three distinct methods (Process-1, Process-2, and Process-3). The fiber extraction process includes washing, sun-drying, manual collection of rind fibers, immersion of rind fibers in NaOH at specific concentrations for specific durations, combing, and drying. In Process-1, the rind fibers were immersed in 5% NaOH for 15 h, while in Process-2 and Process-3, the rind fibers were immersed in 1% NaOH, but the soaking time varied: 25 h for Process-2 and 18 h for Process-3.for 25 h, and in Process-3, the rind fibers were immersed in 1% NaOH for 18 h. The resulting bagasse fibers underwent comprehensive property assessment with a focus on functional group analysis, diameter measurement, and tensile strength assessment. Subsequently, these fibers were used to fabricate composite materials via the 3D SLA printing technique after being treated in a NaOH solution. The Fourier Transform Infrared (FTIR) Spectroscopy results clearly showed that a fraction of hemicellulose and lignin was removed by NaOH, resulting in improved tensile strength of the bagasse fibers. Three-dimensional-printed composites reinforced with bagasse fibers extracted through the P1 method showed the highest improvement in tensile strength (approximately 70%) compared to specimens made from pure resin. The lack of pores in the composite and the observable fiber fracture phenomena clearly indicate that 3D printing technology effectively enhances the quality of the interface between the fiber and the matrix interfacial bonding, consequently resulting in improved tensile properties of the composites. The 3D-printed composites reinforced with bagasse fiber showcased impressive tensile properties and provided solutions to the limitations of traditional composite manufacturing methods. This sets the stage for developing innovative composite materials that combine natural fibers with cutting-edge fabrication techniques, offering a promising path to tackle present and future economic and ecological challenges. [ABSTRACT FROM AUTHOR]

Numerous studies have examined rattan and date palm fibers separately, but none have combined both fibers in a single composite. This research focuses on creating novel hybrid composites using untreated and treated rattan and date palm fibers. Fibers were treated with 3%, 4%, and 5% NaOH solutions. Fiber diameters were measured microscopically. The NaOH treatment enhanced the tensile strength of the fibers. Untreated rattan, midrib, and spadix stem fibers exhibited tensile strengths of 18, 57, and 37 MPa, respectively. Polyester was used as the matrix, combined with fibers in weight fractions of 70 : 30, 75 : 25, and 80 : 20. All composites were made for 1 : 1 rattan–midrib and 1 : 1 rattan–spadix stem fibers. Composites containing 20% treated rattan–midrib fibers displayed the highest tensile and flexural strengths, measuring 13 and 39 MPa, respectively. Meanwhile, rattan–spadix stem composites achieved the highest tensile strength of 14 MPa at 30% treated fiber loading, and the highest flexural strength of 28.91 MPa at 20% fiber wt.%. Additionally, SEM images of the tensile fracture surfaces revealed voids, cracks, and impurities. The goal was to develop a new composite that provides a low cost, structurally sound, and environmentally friendly strong material suited for industrial, construction, and aviation applications. [ABSTRACT FROM AUTHOR]

The main purpose of this research is to observe the effect of alkalisation of rattan, bamboo fibre, and eggshell particles addition in the fabrication of hybrid polyester laminated composite. A 5% NaOH treatment of fibres was conducted, and 5% eggshell particles was added to the composite. The FTIR analysis was done to reveal the presence of nanol, and thermal stabilities were evaluated by TGA, DTG and DTA. Furthermore, water absorption and biodegradability of the composite were also investigated. Mechanical properties were tested with compatible ASTM standards. The 5% NaOH treated 30 wt.% fibre- loading enhanced the tensile strength, flexural strength, impact strength, and hardness by 9%, 2%, 7%, and 4%, respectively compared to the raw composites. On the other hand, the addition of 5% eggshell particles decreased the tensile strength, flexural strength, impact strength, and hardness of the raw 30 wt% fibre-reinforced composite by 5%, 4%, 3%, and 2%, respectively In addition, the raw 30 wt% fibre-reinforced composite has the highest biodegradability, and water absorption percentage than the alkali-treated and eggshell added fibre-reinforced composite. The raw 30 wt% fibre-reinforced composite has dictated over the alkali-treated and eggshell added fibre-reinforced composite in terms of thermal stability. [ABSTRACT FROM AUTHOR]

The present study investigates the 2D numerical analogies to the changes of the droplet shapes during the freefall for a wide range of droplet sizes through the stagnation air. The freefall velocity, shape change due to frictional force during free-fall is studied for different considered cases. With the elapse of time, a droplet with a larger initial diameter is changing its original shape more compared to droplets with a smaller diameter. In addition, the spreading of the droplet during the freefall seems more rapid for the larger-diameter droplet. When a droplet with an initial diameter of 15mmstarts to fall with gravitational force, the diameter ratio is decreasing for droplets with higher density and surface tension while droplets having lower density and surface tension show a diameter ratio greater than one. The spreading and splashing of the droplet on a solid surface and liquid storage at the time of impact are much influenced by the freefall memories of the droplet during the freefall from a certain height. These freefall memories are influenced by the fluid properties, drag force, and the freefall height. However, these freefall memories eventually regulate the deformation of the droplet during the freefall. [ABSTRACT FROM AUTHOR]

The freezing process is significantly influenced by environmental factors and surface morphologies. At atmospheric pressure, a surface below the dew and freezing point temperature for a given relative humidity nucleates water droplets heterogeneously on the surface and then freezes. This paper examines the effect of nanostructured surfaces on the nucleation, growth, and subsequent freezing processes. Microsphere Photolithography (MPL) is used to pattern arrays of silica nanopillars. This technique uses a self-assembled lattice of microspheres to focus UV radiation to an array of photonic jets in photoresist. Silica is deposited using e-beam evaporation and lift-off. The samples were placed on a freezing stage at an atmospheric temperature of 22±0.5°C and relative humidities of 40% or 60%. The nanopillar surfaces had a significant effect on droplet dynamics and freezing behavior with freezing accelerated by an order of magnitude compared to a plain hydrophilic surface at 60% RH where the ice bridges need to cover a larger void for the propagation of the freezing front within the growing droplets. By pinning droplets, coalescence is suppressed for the nanopillared surface, altering the size distribution of droplets and accelerating the freezing process. The main mechanism affecting freezing characteristics was the pinning behavior of the nanopillared surface. [ABSTRACT FROM AUTHOR]

Microscale mechanical systems benefit from microchannel heat sinks' heat transfer efficiency. This study uses six new pin fin shapes embedded in microchannel to improve heat dissipation. The study optimizes geometries based on overall thermal performance for Reynolds numbers ranging from 150 to 350. Validation using numerical and experimental data indicates variations under 10 %. Graphical representations show that the proposed pin fin configurations outperform the baseline case. From numerical investigation, the circular perforated fish fin increases Nusselt number by 25 %, whereas the elliptical fin lowers pressure loss by 66.95 %. Elliptical fins enhance thermal performance by 30 %, proving that novel designs and optimization tactics work. Six machine learning models are considered to predict Nu and pressure drop. Keras and sklearn were used for MLP, MLR, and XGBR was imported from XGBoost. Model performance was assessed using the R2 test, MRE, RMSE, and rRMSE. MLP (R2 test = 0.950, MRE (%) = 11, rRMSE = 2.3 %) and XGBR (R2 test = 0.909, MRE (%) = 2.2, rRMSE = 2.9 %) model a good estimation of Nu. XGBR (R2 test = 0.999, MRE (%) = 1.2, rRMSE = 1.6 %) also estimates pressure drop with good accuracy. KFold cross validation was employed to evaluate the mean CV score of the developed model. • Six novel shaped pin fin incorporation in traditional microchannel heat sinks. • Circular perforated fish fin increases Nu by 25 % and Elliptical fin lowers Δ P by 66.95 %. • MLP model outperforms in predicting Nu with R2test = 0.950 and MRE (%) = 11. • XGBR model is most effective in predicting Δ P with R2test = 0.999 and MRE (%) = 1.2 • Machine learning implementation broaden the range of potential design space of future microchannel. [ABSTRACT FROM AUTHOR]