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This study investigated the convective heat transfer coefficient and friction coefficient in a copper helical double pipe heat exchanger utilizing biosynthetic aqua-based silver (Ag) nanofluids prepared with Histiopteris incisa leaf extract. The nanofluids were characterized using UV–Vis spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and high-resolution transmission electron microscopy. The experimental approach involved the constant heat flux method under laminar flow conditions with flow rates ranging from 100 to 160 litres per hour (LPH). Biosynthesized aqua-based silver nanofluids were synthesized using a one-step biosynthesis method, resulting in volume concentrations ranging from 0.3 to 0.9%. Our findings demonstrated that the biosynthesized aqua-based silver nanofluids exhibited enhanced convective heat transfer compared to pure water. Additionally, the heat transfer coefficient showed an increasing trend with higher volume concentrations of biosynthesized aqua-based silver nanofluids. Notably, the most significant improvement in convective heat transfer, reaching 40%, was achieved with a 0.9% volume concentration of biosynthesized aqua-based silver nanofluids, a flow rate of 140 LPH, and a Dean number of 1400. Moreover, the friction coefficients observed for biosynthesized aqua-based silver nanofluids were 35% higher than those of water in the Dean number range of 1400–2400. [ABSTRACT FROM AUTHOR]

In this present work, characterize the chemical, physical, thermal and Morphological behaviour of raw and alkali-treated (NaOH 5 %,10 % & 15 %) new natural cellulose Habara plant stem fiber (HF). From the chemical analysis, the 10 % alkali-treated HF obtained cellulose (67.9 %), hemicellulose (12.7 %), lignin (11.8 %) wax (0.18 %), moisture (2.44 %) and Ash (1.21 %). Fourier Transform Infrared Spectroscopy Analysis, alkali treatment effectively eliminates hemicellulose and lignin from the surfaces of natural fiber, as seen changes in the FTIR peaks at 1730, 1480, and 1140 cm−1.The X-ray analysis results indicate that, there is crystalline cellulose present, with a crystallinity level of 43.87 %, and that the other components are amorphous. In addition, the thermal stability of lignocellulosic fiber up to 230 °C was observed, and the degradation steps of each major component could be identified. The 10 % alkali-treated HF provides tensile strength of 790.9 MPa, with an elongation at break of about 3.41 %. The Scanning Electron Microscope analysis showcased the morphological changes on the fiber fractured surface, diameter variation, and impurities, etc. The Atomic Force Microscopy was used to determine the surface roughness characteristics of the HF , which confirmed the possible reinforcement in the structure of the polymer matrix composite structure. [ABSTRACT FROM AUTHOR]

Mullite is the most attractive material in Material Science for TBC—thermal barrier coatings. As a TBC material, enhancement in its properties like thermal shock resistance is reported when an intermittent phase like lanthanum oxide—La2O3 is introduced. In this present research, effort has been put to identify La2O3 as an equivalent TBC material to Zirconia—ZrO2. A mixture of MZ (Mullite-ZrO2) and ML (Mullite-La2O3) at 10-30% weight ratio as top coat and NiCr as bond coat, is plasma sprayed on A356 aluminium specimen treated to T6 condition. The results obtained indicate that the ML2 plasma sprayed coatings exhibit regularly formed grain structure that increases the fracture toughness. The average hardness value and average adhesion strength values of the ML coatings were are 13.3 GPa and 9.5 MPa, which was 1.6 and 1.2 times larger than the traditional Zirconia coatings. The ML coatings also showed no corrosion or spallation or crack formation after 100 h of NACL salt spray test and after 100 cycles of thermal shock load at 550 °C at a cycle time of 10 min. [ABSTRACT FROM AUTHOR]

In this research work, the untreated and various concentrations of alkali treated continuous mulberry fibers were used as reinforcement in polyester matrix and its static and dynamic mechanical properties were investigated. The composites were fabricated using untreated, 5%, 10%, and 15% alkali treated mulberry fibers (ATMF) reinforced in polyester resin by compression molding technique. The result showed that the 10% alkali treated mulberry fiber composite (ATMFC) considerable increase in tensile, flexural, and impact properties compared to untreated, 5% and 15% alkali treated mulberry fiber composites. The 15% alkali treated mulberry fiber composite showed decrease in water absorption property. The fractured surface morphology of composite samples was examined by Scanning Electron Microscopy (SEM). The Dynamic Mechanical Analysis (DMA) shows that the 10% alkali treated mulberry fiber composite enhanced storage and loss modulus compared to untreated, 5% and 15% alkali treated mulberry fiber composites. The weight loss of untreated, 5%, 10%, and 15% alkali treated composites were studied under varying temperature by Thermo Gravimetric Analysis (TGA) and Differential Thermo Gravimetric analysis (DTG). POLYM. COMPOS., 39:E1908–E1919, 2018. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

In this research the fibers were extracted from mulberry plant and treated with various concentrations of alkali solution (NaOH) such as 5, 10, and 15%, and their physical, chemical, mechanical, morphological, and thermal properties were investigated experimentally. Due to alkali treatment, it was observed that the density of mulberry fibers increased while the diameter of fibers reduced. The chemical analyses showed that the cellulose content increased and hemicellulose, lignin, wax, and ash contents were found to be reduced due to alkali treatment. The chemical species present in the fibers were characterized by Fourier transform infrared spectrometry. In addition, tensile test showed that 5% alkali-treated fibers exhibited a tensile strength of 605.61 ± 41.34 MPa, tensile modulus of 11.78 ± 1.93 GPa, and strain at break of 4.73 ± 1.06%. The surface texture and thermal properties of raw- and alkali-treated fibers were examined using scanning electron microscopy and thermogravimetric analysis and differential thermogravimetric analysis. [ABSTRACT FROM AUTHOR]

Steering knuckle is a prominent component of an automobile steering system. It is subjected cyclic loads from the suspension system during its service life. The Spheroid Graphite (SG) iron is the most commonly used material for manufacturing the steering knuckle. Fatigue behaviour is therefore a key consideration in its design and performance evaluation. Geometric modelling and stress analysis of such steering knuckle using finite element analysis software is carried out. Then the fatigue life of steering knuckle made from SG iron has been evaluated under the different load conditions and the results have been compared. [ABSTRACT FROM AUTHOR]

An experimental study to determine the wear behaviour of Agave fibre reinforced epoxy composites (AFEC) has been conducted. Epoxy composites reinforced with Agave fibres of length 3, 5 and 7 mm namely were prepared by hand lay up and open mould technique. Wear behaviour of the composite was responsive to varied load, fibre length and sliding velocity. Observations of this experiment exposed that, AFEC3 has a good degree of wear behaviour when sliding against the stainless steel. The worn surfaces and wreckage were observed under scanning electron microscope. Finally, microscopic observation indicated that the AFEC3 has the ability to have a fairly good bonding with the epoxy matrix. [ABSTRACT FROM AUTHOR]

Abstract: Composites based on short Agave fibres (untreated and alkali treated) reinforced epoxy resin using three different fibre lengths (3mm, 7mm and 10mm length) are prepared by using hand lay up and compression mould technique. The materials were characterized in terms of tensile, compressive, flexural, impact, water absorption properties and machinability behaviour. All mechanical tests showed that alkali treated fibre composites withstand more fracture strain than untreated fibre composites. As evidenced by the dynamic mechanical analysis (DMA) tests, the thermo-mechanical properties of the composite with alkali treated Agave fibre were considerably good as alkali treatment had facilitated more sites of fibre resin interface. The machinability and atomic force microscope (AFM) studies were carried out to analyze the fibre–matrix interaction in untreated and alkali treated Agave fibre–epoxy composites. [Copyright &y& Elsevier]

Abstract: The mechanical properties such as tensile, compressive, flexural, impact strength and water absorption of the alkali treated continuous Agave fibre reinforced epoxy composite (TCEC) and untreated continuous Agave fibre reinforced epoxy composite (UTCEC) were analysed. A comparison of the surfaces of TCEC and UTCEC composites was carried out by dynamic mechanical analysis (DMA), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The thermomechanical properties of the composite reinforced with sodium hydroxide (NaOH) treated Agave fibres were considerably good as the shrinkage of the fibre during alkali treatment had facilitated more points of fibre resin interface. The SEM micrograph and FTIR spectra of the impact fracture surfaces of TCEC clearly demonstrate the better interfacial adhesion between fibre and the matrix. In both analyses the TCEC gave good performance than UTCEC and, thus, there is a scope for its application in light weight manufacture in future. [Copyright &y& Elsevier]

Abstract: The present research work studies the effect of cryogenic treatment on the residual stress state in 4140 steel. Two kinds of cryogenic treatment, namely shallow (SCT, −80°C×5h) and deep cryogenic treatment (DCT, −196°C×24h) were carried out between quenching and tempering in conventional heat treatment process. The results evidenced an increase in the compressive residual stress in steel are subjected to cryogenic treatment before tempering. X-ray diffractometry revealed that residual stresses are relieved during tempering, according to the redistribution of carbon in martensite and the precipitation of transition carbides. While conventional heat treatment (CHT) and shallow cryogenic treatment (SCT) promote a tensile state of residual stress, DCT shows a compressive residual stress. [ABSTRACT FROM AUTHOR]

This paper aims at introducing new natural fibers for use as fillers in a polymeric matrix enabling production of cost-effective, biodegradable, and lightweight composites for load carrying structures. Agave (Agave americana) leaf fiber, one such kind, is rich in cellulose, relatively inexpensive, and abundantly available. In this study, investigations on extraction of agave leaf fiber are carried out and its physical, chemical, and mechanical properties such as the cross section, length distribution, weight distribution, density, cellulose, hemicellose, lignin, and wax are determined experimentally. Analysis of the tensile force of the fiber, elongation of the fiber, and water absorption of the fiber in load direction and fiber length are also carried out. The effect of alkali treatment on the fiber at varying concentrations, temperature, and holding time are also studied. A scanning electron microscope is used to analyze the morphology of raw and treated fibers. [ABSTRACT FROM PUBLISHER]

Tool wear prediction plays an important role in industry for higher productivity and product quality. Flank wear of cutting tools is often selected as the tool life criterion as it determines the diametric accuracy of machining, its stability and reliability. This paper focuses on two different models, namely, regression mathematical and artificial neural network (ANN) models for predicting tool wear. In the present work, flank wear is taken as the response (output) variable measured during milling, while cutting speed, feed and depth of cut are taken as input parameters. The Design of Experiments (DOE) technique is developed for three factors at five levels to conduct experiments. Experiments have been conducted for measuring tool wear based on the DOE technique in a universal milling machine on AISI 1020 steel using a carbide cutter. The experimental values are used in Six Sigma software for finding the coefficients to develop the regression model. The experimentally measured values are also used to train the feed forward back propagation artificial neural network (ANN) for prediction of tool wear. Predicted values of response by both models, i.e. regression and ANN are compared with the experimental values. The predictive neural network model was found to be capable of better predictions of tool flank wear within the trained range. [ABSTRACT FROM AUTHOR]

Optimization of cutting parameters is valuable in terms of providing high precision and efficient machining. Optimization of machining parameters for milling is an important step to minimize the machining time and cutting force, increase productivity and tool life and obtain better surface finish. In this work a mathematical model has been developed based on both the material behavior and the machine dynamics to determine cutting force for milling operations. The system used for optimization is based on powerful artificial intelligence called genetic algorithms (GA). The machining time is considered as the objective function and constraints are tool life, limits of feed rate, depth of cut, cutting speed, surface roughness, cutting force and amplitude of vibrations while maintaining a constant material removal rate. The result of the work shows how a complex optimization problem is handled by a genetic algorithm and converges very quickly. Experimental end milling tests have been performed on mild steel to measure surface roughness, cutting force using milling tool dynamometer and vibration using a FFT (fast Fourier transform) analyzer for the optimized cutting parameters in a Universal milling machine using an HSS cutter. From the estimated surface roughness value of 0.71 μm, the optimal cutting parameters that have given a maximum material removal rate of 6.0×103 mm3/min with less amplitude of vibration at the work piece support 1.66 μm maximum displacement. The good agreement between the GA cutting forces and measured cutting forces clearly demonstrates the accuracy and effectiveness of the model presented and program developed. The obtained results indicate that the optimized parameters are capable of machining the work piece more efficiently with better surface finish. [ABSTRACT FROM AUTHOR]

The research article address, the mechanical properties such as fatigue, impact strength and tribological properties of Austempered ductile iron (ADI) has been investigated. The samples of ADI iron were austenitized at 927°C for 2 hrs and later it was under austempering process for 2 hrs at a temperature range of 240°C to 400°C. Experiments under axial loading has been carried out on three different compositions (without Ni(X), 0.22 wt % Ni (X1), 0.34 wt. % Ni (X2). Fabricated test bars were converted in to as per ASTM standard samples for different tests. In order to study the influence of chunky nickel morphology studies on fatigue life and impact strength were carried out on a second set of specimens without any microstructural defect. Metallurgical analyses were performed on all the samples of heat treated samples (AF - Ausferrite, MB - Mixed bainite, M - Martensite, RA - Retained Austenite and N-Nodule) were found and compared. It was found that a mean content of 22% of chunky nickel in the microstructure (with respect to total Ni content) influence considerably the fatigue and impact strength properties of the cast iron. Moreover tribological properties of the specimens were also studied under dry sliding conditions at various sliding speed and load. The wear resistance and coefficient of friction were found to increase with increase in load and sliding speed. [ABSTRACT FROM AUTHOR]

Abstract: In the present paper, the wear behaviour of aluminium metal matrix composite (Al MMC) sliding against automobile friction material has been compared with the conventional grey cast iron. The wear tests have been carried out on a pin on disc machine, using pin as brake shoe lining material and discs as A356/25SiCp Al MMC and grey cast iron materials. Pins of 10mm diameter have been machined from a brake shoe lining of a commercial passenger car. The grey cast iron disc has been machined from a brake drum of a commercial passenger car. The Al MMC disc has been manufactured by stir casting technique using A356 aluminium alloy and 25% silicon carbide particles and machined to the required size. The friction and the wear behaviour of Al MMC, grey cast iron and the semi-metallic brake shoe lining have been investigated at different sliding velocities, loads and sliding distances. The worn surfaces and sub-surface regions of MMC, the cast iron and the lining have been analysed using optical micrographs. The present investigation shows that the MMCs have considerable higher wear resistance than conventional grey cast iron while sliding against automobile friction material under identical conditions. A gradual reduction of friction coefficient with increase of applied load is observed for both cast iron and Al MMC materials. However, in all the tests it is observed that the friction coefficient of Al MMC is 25% more than the cast iron while sliding under identical conditions. The wear of the lining material has been observed more when sliding against MMC disc because of the ploughing of the lining material by the silicon carbide particles. The wear grooves formed on the lining material while sliding against MMC and cast iron have been analysed using optical micrographs. [Copyright &y& Elsevier]