72 research outputs found
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A feasibility study of various joining techniques for three-dimensional printed polylactic acid and wood-reinforced polylactic acid biocomposite
Current research assesses various joining techniques such as an adhesive bond, direct three-dimensional (3D) printing, and an ultrasonic welding of 3D printed dissimilar thermoplastic materials such as PLA and wood reinforced PLA composites. The importance of the present study is to determine the effective technique for joining the 3D printed complex structural profiles. Mechanical responses such as lap shear strength and shore D hardness of the various joints were studied and compared experimentally. The results highlighted that 15-17 % of higher shear strength was obtained for the ultrasonically welded joints compared with the direct 3D printed PLA and wood PLA lap joints. Macroscopic investigation of the ultrasonic welded polymeric joint exhibits the melting of polymers and wet the interface—the results in inter-molecular diffusion of polymeric chains and entanglement of polymers under the respective conditions
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Mechanical and tribological behaviour of three-dimensional printed almond shell particles reinforced polylactic acid bio-composites
Recently, composite filament development for three-dimensional printing has emerged and is used for numerous applications. The present research work develops neat polylactic acid and Almond Shell Particles reinforced polylactic acid bio-composites for three-dimensional printing and investigates the effects of printing orientation, including 0°, 45° and 90° orientation, on the tribological and mechanical behaviours of three-dimensional printed materials. The novel almond shell particles reinforced polylactic acid filaments are extruded by the filament extrusion method with the presence of 10% almond shell particles in the polylactic acid matrix, and the samples are three-dimensional printed by the fused filament fabrication technique. Mechanical characteristics such as tensile, flexural, compressive strength, and shore hardness are evaluated with respect to various three-dimensional printing orientations. The surface quality of the three-dimensional printed polylactic acid composite samples is analysed with respect to length and diameter deviation. Length accuracy of the 90° oriented polylactic acid and almond shell particles reinforced polylactic acid bio-composite samples exploits a better accuracy of 99.12% and 98.81%, respectively. It is shown that adding almond shell particles to the polylactic acid matrix decreases the flexural and tensile strength. Among the printing orientations, 0° flat samples result in the maximum tensile strength of 36 and 28 MPa for the neat polylactic acid and almond shell particles reinforced polylactic acid composites, respectively. The lowest contact angle of 54° is observed on the almond shell particles reinforced polylactic acid bio-composites three-dimensional printed with a 90° orientation. The highest contact angle value of 94° is observed on the neat polylactic acid three-dimensional printed with a 0° printing orientation. A tribological study is carried out under dry conditions on the pin-on-disc tribometer by varying the sliding speed (1, 2, and 3 m/s) and load (10, 20, and 30 N). The result shows that the lowest coefficient of friction of 0.22 is achieved for the almond shell particles reinforced polylactic acid bio-composite samples with a 0° printing orientation under a sliding load of 10 N. These kinds of newly developed compostable materials can be used for developing disposable orthotic foot appliances
Formulations of Plant Growth-Promoting Microbes for Field Applications
Development of a plant growth-promoting (PGP) microbe needs several steps starting with isolation of a pure culture, screening of its PGP or antagonistic traits by means of different efficacy bioassays performed in vitro, in vivo or in trials under greenhouse and/or field conditions. In order to maximize the potential of an efficient PGP microbe, it is essential to optimize mass multiplication protocols that promote product quality and quantity and a product formulation that enhances bioactivity, preserves shelf life and aids product delivery. Selection of formulation is very crucial as it can determine the success or failure of a PGP microbe. A good carrier material should be able to deliver the right number of viable cells in good physiological conditions, easy to use and economically affordable by the farmers. Several carrier materials have been used in formulation that include peat, talc, charcoal, cellulose powder, farm yard manure, vermicompost and compost, lignite, bagasse and press mud. Each formulation has its advantages and disadvantages but the peat based carrier material is widely used in different part of the world. This chapter gives a comprehensive analysis of different formulations and the quality of inoculants available in the market, with a case study conducted in five-states of India
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Preparation and performance evaluation of 3D printed poly lactic acid composites reinforced with silane functionalized walnut shell for food packaging applications
The main goal of this work is to develop silane-grafted Poly Lactic Acid (PLA) bio-composites reinforced by various compositions of 0, 5, 10, and 15 wt% Walnut shell (WAL) particles and 3D printed by Fused Filament Fabrication (FFF) technique. The composite filaments are extruded by filament extrusion technique, and the 3D printed Walnut shell/PLA (WAL/PLA) bio-composite samples are evaluated for various mechanical, water absorption and biodegradation properties. The effect of silane grafting increases the crystallinity index value of 61.2% for the silane-grafted WAL particles. The mechanical property results reveal that using WAL particles reduces the strength value and improves the modulus of both untreated and silane-treated WAL/PLA composites. The silane grafted 15% WAL/PLA samples show the highest shore hardness value of 71 MPa and the heat deflection temperature of 63.79 ℃. The biodegradation test results reveal that the untreated 15% WAL/PLA composites have a higher mass loss of 6.4% and 19.1% for 30 and 60 days, respectively. Fractographical results of silane-treated 10% WAL/PLA composites exhibit a uniform distribution of WAL particles with minimum particle pull-out from the polymeric matrix. The findings of this study affirm the potential of WAL/PLA bio-composites as a viable and sustainable material for application in food storage and service
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Study on the impact of material extrusion factors on the compressive characteristics of honeycomb lattice-structured Onyxâ„¢ composites
Honeycomb structures have a wide variety of applications in engineering, architecture, and transportation. Latticing, facilitated by additive manufacturing (AM), can effectively accelerate development of customizable structures. This paper introduces a systematic experimental approach to investigate the impact of various material extrusion (MEX) factors on the physical and mechanical characteristics of triangular honeycomb lattice-structured OnyxTM composites. The experimental study is conducted by varying MEX factors such as layer height, infill density, build orientation, infill pattern, and number of walls and their impact on the physical property (density), mechanical property (compressive strength), and structural property of the lattice structure (structural area deviation). The results highlight that the optimal combination for obtaining the maximum compressive strength is 0.1 mm layer height, 50 % infill density, 90° build orientation, rectilinear infill pattern, and a wall count of three. The MEX factors like infill density, build orientation and infill pattern have a significant impact on the physical properties. Furthermore, the lattice-structured OnyxTM composite with three walls exhibits buckling phenomenon at a slower rate when compared to the lattice-structured OnyxTM composites with one and two walls. The structural area deviation of the integrated lattice is majorly influenced by the layer height and build orientation. The optimized condition for a higher load bearing capability is employed for developing a topologically optimized lattice-structured camera bracket for sports-action cameras
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Predictive modeling of compressive strength for additively manufactured PEEK spinal fusion cages using machine learning techniques
The current study delves into the utilization of Machine Learning (ML) algorithms to evaluate the mechanical properties of additively manufactured PEEK spinal fusion cages. In this research, a range of ML models, including Linear Regression (LiR), Lasso Regression (LaR), Decision tree (DT), and K-Nearest Neighbor (KNN) are harnessed to enhance compressive strength prediction. Ensemble learning techniques such as bagging, boosting, and stacking are applied to identify the most accurate ML model in terms of achieving heightened accuracy and minimized errors. To facilitate this, spinal fusion cages are 3D printed using the Fused Filament Fabrication (FFF) technique and subsequently tested using a Universal Testing Machine (UTM). The development of ML models involves the exploration of independent material-extrusion factors, encompassing layer height (0.1 mm, 0.2 mm, 0.3 mm), printing temperature (370℃, 390℃, 410℃), printing speed (10 mm/sec, 30 mm/sec, 50 mm/sec), infill density (40%, 70%, 100%), build orientation (0º, 45º, 90º), and line width (0.1 mm, 0.2 mm, 0.3 mm). The robustness and effectiveness of the developed ML models in predicting compressive strength properties are optimized through comprehensive error metric analysis. The results indicate that the LiR model, particularly when implemented under the boosting ensemble technique, demonstrates the highest accuracy with a Mean Absolute Error (MAE) of 0.657, Root Mean Square Error (RMSE) of 0.758, and Median Absolute Error (MedAE) of 0.634. This underscores the potential of LiR for precise compressive strength prediction in 3D-printed PEEK spinal fusion cages for spinal and maxillomandibular reconstruction
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