Effect of Fiber Orientation and Stacking Sequence on Mechanical and Thermal Characteristics of Banana-Kenaf Hybrid Epoxy Composite

The usage of hybrid natural composites has surged in almost all fields of engineering due to their advantage of possessing high strength to weight ratio and biodegradability. This paper deals with the fabrication and investigation of mechanical and thermal properties of banana-kenaf glass fiber reinforced epoxy composite which is relatively a newer hybrid composite. In this study, the composite is fabricated by a hand layup process with different fiber orientations and also with different volume fractions. The composites are prepared with five different proportions of banana-kenaf fibers. Various mechanical and thermal tests are conducted and the result shows that the hybrid composite in which fibers are arranged at 45⁰ inclination has better properties than the others. Also, failure morphology analysis is done using a Scanning Electron Microscope (SEM) through which the internal structures of the tested specimen are analysed.     

Structural,electrical and electrochemical properties of polyacrylonitrile-ammonium hexaflurophosphate polymer electrolyte system

Polyacrylonitrile (PAN) based polymer electrolyte membranes complexed with Ammonium hexafluorophosphate (NH₄PF₆) with different molar concentration are prepared by solution casting method. Increase in the amorphous nature by the addition of Ammonium salt and the formation of polymer-salt complex are confirmed by X ray diffraction studies and infrared spectroscopy respectively. The glass transition temperature is measured for all membranes and it showed a lowest value for the PAN complexed with 20 mol% of NH₄PF₆. Electrical properties are studied by AC impedance spectroscopy. An ionic conductivity of the order of 10^?3 Scm^?1 is obtained for the 80 PAN / 20 NH₄PF₆ polymer electrolyte. Conductivity, dielectric and modulus spectra from the impedance data are analysed to understand the ionic transport mechanism. Transference number measurement is done to study the ionic contribution to the charge transport. A proton battery with the configuration, Zn+ ZnSO₄. 7H₂O /80 PAN / 20 NH₄PF₆ / PbO₂ +V₂O₅ has been constructed and its discharge characteristics are studied.     

Effect of TiO2 and nozzle geometry on diesel emissions fuelled with biodiesel blends

In this present study, the compression ignition engine was designed to run on CIME (Calophyllum inophyllum methyl ester) biodiesel with nanoparticles. The TiO₂ nanoparticle is added to the biodiesel in the form of nanofluid at concentration levels of 100?ppm whereas ethanox is added at levels of 100, 200 and 500?ppm. The nanoparticle and the ethanox are dispersed by the ultrasonication process. The addition of nanofluid reduces the particulate emission like nitrogen oxide (NO_x) at 100% load. The efficiency is better and emission is reduced owing to the influence of explosion of water molecules present in the biodiesel. We found ethanox to be a superlative nanofluid to reduce the emission of toxic gas at appreciable levels. We have witnessed a 20% reduction in emission of NO_x and 10% reduction of other particulate emission. In addition, the exit geometry of exhaust is modified from a circular shape to an elliptical one and the consequence of the geometry is calculated.     

Finite element modeling of distortion during liquid phase sintering

Liquid phase sintering (LPS) is a common technique to consolidate materials that are difficult to process by fusion techniques, such as tungsten heavy alloys. One of the major processing difficulties associated with liquid phase sintered alloys is component distortion and loss of component shape. In LPS, this distortion is the result of viscous flow driven by curvature effects and gravity. A finite element model is developed for viscous flow of the semisolid sintering structure using Stokes equations. This model considers solid volume fraction and effective viscosity of the solid-liquid mixture. The simulation predictions are compared to distortion results for microgravity and ground-based sintering experiments, and they show good agreement. The model results indicate that the effective semisolid viscosity is significantly greater than the liquid metal viscosity. Hence, future work needs to quantitatively examine the factors controlling viscosity and the benefits from such high viscosities in liquid phase sintered systems.     

Solvothermal‐assisted green synthesis of hybrid Chi‐Fe3 O4 nanocomposites: a potential antibacterial and antibiofilm material

In this present study, a hybrid Chi‐Fe₃ O₄ was prepared, characterised and evaluated for its antibacterial and antibiofilm potential against Staphylococcus aureus and Staphylococcus marcescens bacterial pathogens. Intense peak around 260 nm in the ultraviolet–visible spectrum specify the formation of magnetite nanoparticles. Spherical‐shaped particles with less agglomeration and particle size distribution of 3.78–46.40 nm were observed using transmission electron microscopy analysis and strong interaction of chitosan with the surface of magnetite nanoparticles was studied using field emission scanning microscopy (FESEM). X‐ray diffraction analysis exhibited the polycrystalline and spinel structure configuration of the nanocomposite. Presence of Fe and O, C and Cl elements were confirmed using energy dispersive X‐ray microanalysis. Fourier transform infrared spectroscopic analysis showed the reduction and formation of Chi‐Fe₃ O₄ nanocomposite. The antibacterial activity by deformation of the bacterial cell walls on treatment with Chi‐Fe₃ O₄ nanocomposite and its interaction was visualised using FESEM and the antibiofilm activity was determined using antibiofilm assay. In conclusion, this present study shows the green synthesis of Chi‐Fe₃ O₄ nanocomposite and evaluation of its antibacterial and antibiofilm potential, proving its significance in medical and biological applicationsInspec keywords: visible spectra, particle size, magnetic particles, nanocomposites, nanoparticles, X‐ray diffraction, nanofabrication, transmission electron microscopy, X‐ray chemical analysis, nanomagnetics, microorganisms, antibacterial activity, iron compounds, ultraviolet spectra, biomedical materials, field emission scanning electron microscopy, Fourier transform infrared spectra, filled polymers, crystal growth from solution, polymer structureOther keywords: potential antibacterial material, antibiofilm potential, magnetite nanoparticles, solvothermal‐assisted green synthesis, hybrid Chi‐Fe₃ O₄ nanocomposites, staphylococcus aureus, staphylococcus marcescens, bacterial pathogens, ultraviolet–visible spectrum, spherical‐shaped particles, particle size, transmission electron microscopy, FESEM, field emission scanning electron microscopy, X‐ray diffraction, spinel structure, polycrystalline structure, energy dispersive X‐ray microanalysis, Fourier transform infrared spectroscopic analysis, deformation, bacterial cell walls, Fe₃ O₄      

Experimental study of the kinetics of transient liquid phase solidification reaction in electroplated gold-tin layers on copper

The kinetics of transient liquid phase (TLP) solidification in Au-Sn layers electroplated on Cu foil was investigated using differential scanning calorimetry (DSC). The solidification reaction takes place between a eutectic liquid of melting point 280 °C, which is shown to form in preference to other compositions, and an excess gold-rich layer. The solidification kinetics and the amount of melt formed were measured as a function of foil aging time. It is shown that the well-documented rapid interdiffusion at low temperatures between gold and tin can account for a decrease in the amount of melt produced during heating with age time. An estimate of the effective diffusivity of tin into gold at 295 °C has been obtained from measured solidification rates. The effect of copper diffusing through the gold film on the solidification kinetics was also investigated.     

Structural Model to Predict the Failure Behavior of Plated Reinforced Concrete Beams

This paper presents a theoretical model, based on truss analogy, to analyze the structural behavior at failure of reinforced concrete beams with steel plates or fiber-reinforced polymer lamitates bonded to their tension faces. The analytical approach, incorporated in the framework of strut-and-tie models, takes into account the nonlinear behavior of materials and of the structural member. In addition, it includes the load transfer mechanism to reflect the plate-debonding phenomenon and associated cracking of concrete cover, both of which play a critical role in the failure process of plated beams. The model, which takes into consideration all the possible failure modes of plated beams, is capable of predicting the beam load-carrying capacity at ultimate and, also, of indicating the associated mode of failure. It aims to develop a rational engineering analysis in a field which until now has been studied with linear elastic approaches or empirical methods. The proposed model has been validated by comparing the results obtained in the present analysis with over a hundred experimental results available in published literature. Furthermore, the results obtained with the present analysis are compared with those obtained by two other models, and it is shown that the model proposed here provides a consistent and satisfactory correlation with a wide range of reinforced concrete beam tests strengthened with steel or polymer composite plates.     

Effect of water of crystallization on synthesis of nanocrystalline ceria by non-hydrolytic method

Nanocrystalline ceria has been synthesized by a non-hydrolytic method using organic solvent and precipitant. The effect of the source compound on final nanocrystalline powder was investigated. The cerium nitrate hexahydrate subjected to different vacuum/thermal treatments to get cerium source compound having different extent of water of crystallization. The nanoceria, synthesized from these compounds was characterized by TGA-MS, XRD, HR-TEM and AFM.     

Benzimidazole-based dendritic nanofiltration membranes

A dendritic-benzimidazole (D-BI) has been prepared using polyphosphoric acid (PPA) as a condensing medium with diaminobenzidine (DAB), 1,3,5-benzene tricarboxylic acid, and isophthalic acid as monomers. The structure of D-BI was ascertained by elemental analysis, FTIR, ¹H NMR, and solid-state ¹³C-NMR. The D-BI was incorporated into polysulphone (PSf) by blending with polyvinylpyrrolidone (PVP K-30) as a macromolecular additive. The membranes were cast by phase inversion technique. The physical properties such as surface morphology and the chemical properties such as contact angle and the performance attributes, such as NOM rejection, salt rejection, and pure water flux were studied. It is imperative that the infusibility of rigid polymeric backbone is overcome by the introduction of polar moieties with no compromise on thermal stability. The membranes displayed substantial increase in thermal stability with D-BI content. The marginal increase in flux has been attributed to the branching and steric effect of D-BI. This is because the introduction of polar group efficiently affords to stabilize the adjacent aromatic rings. The salt rejection shows the order of MgSO₄ ≈ Na₂SO₄ > MgCl₂ > NaCl, which follows that the divalent ions are rejected more than monovalent ions. The antifouling behaviour was also significant as the irreversible fouling (R_Ir 9%), which was found to be minimal for D-BI-incorporated membrane. The blended membranes exhibited good hydrophilicity, antifouling, and fairly good rejection of salts.