Mechanical engineering

The authors regret that there were errors in the calculation of the values of the work of adhesion. Consequently, the work of adhesion values in tables 2 and 3 and in two sentences should change. These changes do not in any way alter the conclusions of this paper as well as the discussions. These corrections are mentioned below and have been updated on the online version. 1. Correction in Table 2

A cross-over in the interfacial strength, with increase in the separation rate, is observed between graphite-cis-1,4-polyisoprene and amorphous silica-cis-1,4-polyisoprene interfaces. Molecular dynamics simulations are used to compare the traction-separation characteristics of the two interfaces in the opening mode of separation at various separation rates and temperatures above the glass transition temperature of cis-1,4-polyisoprene. It was observed that various parameters governing the interface strength, such as strength modulus (ratio of peak traction to the separation at peak traction), peak traction, and the work of adhesion are higher for the silica substrated interface at very low separation rates. However, at higher rates, the graphite substrated interface showed higher values for the strength parameters. The reasons for this interface strength cross-over are explained using the potential energy, mobility, entanglement strength, tensile stiffness, and densities of the polymer over both substrates and the interface cohesive binding energy. Based on these observations, it is concluded that silica filled rubber nanocomposites are suitable for normal automobile tire applications; however, graphite fillers may be more suitable for resisting very large impact loads.

Energy efficiency (EE) improvement is one of the most crucial elements in the decarbonization of industry. EE potential within industries largely remains untapped due to the lack of information regarding potential EE measures (EEM), knowledge regarding energy use, and due to the existence of some inconsistencies in the evaluation of energy use. Classification of energy end-using processes would increase the understanding of energy use, which in turn would increase the detection and deployment of EEMs. The study presents a novel taxonomy with hierarchical levels for energy end-use in manufacturing operations for the engineering industry, analyzes processes in terms of energy end-use (EEU) and CO2 emissions, and scrutinizes energy performance indicators (EnPIs), as well as proposing potential new EnPIs that are suitable for the engineering industry. Even though the study has been conducted with a focus on the Swedish engineering industry, the study may be generalizable to the engineer...

ÐThe synthesis, microstructural characterization and microhardness of nanocrystalline B2-phase NiAl intermetallic are discussed in this paper. Nanophase NiAl powders were prepared by mechanical alloying of elemental Ni and Al powders under an argon atmosphere for dierent times (0±48 h). The alloyed nanocrystalline powders were then consolidated by shock compaction at a peak pressure of 4± 6 GPa, to 83% dense compacts. Characterization by transmission electron microscopy (TEM) revealed that the microstructure of the shock-consolidated sample was retained at the nanoscale. The average crystallite size measurements revealed that mechanically alloyed NiAl grain size decreased from 48 227 to 923 nm with increasing mechanical alloying time from 8 to 48 h. The long-range-order parameters of powders mechanically alloyed for dierent times were determined, and were observed to vary between 0.82 for 5 h and 0.63 for 48 h of milling time. Following shock compaction, the long-range-order parameter was determined to be 0.76, 0.69 and 0.66, respectively, for the 16, 24 and 48 h alloyed specimens. Both the mechanically alloyed nanocrystalline NiAl powder and the shock-consolidated bulk specimen showed evidence of grain boundary dislocations, subgrains, and distorted regions. A large number of grain boundaries and defects were observed via high resolution TEM (HRTEM). Shear bands were also observed in the mechanically alloyed NiAl intermetallic powders and in the shock-consolidated compacts. Microhardness measurements of shock-consolidated material showed increasing microhardness with increasing crystallite size re®nement, following Hall±Petch behavior.

This paper investigates the mechanical properties and forming capabilities of magnesium ZE10. Mechanical properties are observed by stress strain diagram. Three types of the samples are used which are machined from thin sheets of 0.8mm thickness in 00, 450, 900 of the rolling direction (RD). The samples are then tested at different temperatures varying from room temperature (RT) to 400°C. The factors that are considered in tensile tests are Youngs modulus, Yield strength, Ultimate tensile strength and fracture strain. The later part of this paper is devoted to deep drawing tests in which specimen are drawn from room temperature to 250°C. In these tests variation of Limit Drawing Ratio (LDR) is investigated at different temperatures. The other parameters observed are drawing depth, punch force, blank holder force and their variation from room temperature to elevated temperature.

The heat and mass transfer characteristics of a micropolar nanofluid-filled cubic cavity are investigated with different types of nanoparticles (Al 2 O 3 , TiO 2, Cu and Ag). Pure water is assumed as the base fluid. The governing equations are simplified by means of vorticity-vector potential formulation and subsequently solved numerically using the finite volume method. The influences of relevant parameters on heat and mass transfer characteristics are well explored and the results show that for the micropolar nanofluid model both heat and mass transfer rates and the three-dimensional character of the flow are smaller compared with that of a pure nanofluid model. It is also found that the rate of heat and mass transfer decreases with an increase in vortex viscosity parameters as well as volume fractions. The enhancement in the volume fraction of nanoparticles weakens both flow strength and three-dimensional nature of the flow, which are more prominent in the thermal buoyancy dominated flow. The average Nusselt and Sherwood numbers decrease with the increase in the volume fraction of nanoparticles resulting in a significant enhancement in thermal properties of nanofluids with elevated heat and mass transport features. The effects of type of nanoparticles on the rate of heat and mass transfer and flow structure are analyzed.

The objectives of the present research work are the three-dimensional computational analysis and predictions on double-diffusive natural convection in a cubic cavity filled with Cu-Al 2 O 3 /water micropolar hybrid nanofluid. The governing equations are carefully modified employing vorticity-vector potential formulation and are solved by the finite volume method. Performance enhancement of Cu-Al 2 O 3 /water micropolar hybrid nanofluid is judiciously compared with the Cu/water simple nanofluid. Besides, the influences of concentration of nanoparticles, Rayleigh number, buoyancy ratio, and micropolar vortex parameter on the flow field and heat transfer are critically analyzed. The results show that heat and mass transfer rates are lower for a micropolar nanofluid model when compared to the pure nanofluid model. The hybrid micropolar nanofluid displays more heat and mass transfer rates for thermal buoyancy dominated zones when compared with traditional nanofluid. Conversely, the heat and mass transfer rates are decreased when using micropolar hybrid nanofluid for the solutal-dominated regime. The enhancement of micropolar viscosity parameter results in a decrease of average Nusselt and Sherwood numbers which are more perceptible in the thermal buoyancy dominated flow.

The choice of suitable inoculants in the grain refinement process and subsequent enhancement of the characteristics of the composites developed is an important materials research topic, having wide scope. In this regard, the present work is aimed at finding the appropriate composition and size of fly ash as inoculants for grain refinement of the aluminum AA 5083 composites. Fly ash particles, which are by products of the combustion process in thermal power plants, contributing to the large-scale pollution and landfills can be effectively utilized as inoculants and interatomic lubricants in the composite matrix–reinforcement subspaces synthesized in the inert atmosphere using ultrasonic assisted stir casting setup. Thus, the work involves the study of the influence of percentage and size of the fly ash dispersions on the tensile and impact strength characteristics of the aluminum AA 5083/7.5SiC composites. The C type of fly ash with the particle size in the series of 40–75 µm, 76–100...

This comparative study inspects the MHD three-dimensional revolving flow and temperature transmission of a radiative stretching surface. The flow of nanofluid is modeled using the Tiwari and Das model. Water is the base fluid, and the nanoparticles are composed of two different types of nanoparticle, i.e., gold and silver (Au and Ag). The non-radiative heat flow notion is examined in a temperature field that results in a nonlinear energy equation. Conformist transformations are used to generate a self-similar arrangement of the leading differential system. The resulting system has an intriguing temperature ratio constraint, which shows whether the flow has a little or significant temperature differential. By using a powerful mathematical technique, numerical results are obtained. The solutions are influenced by both stretching and rotation. The difference in velocity constituents with the elements’ volume fraction is non-monotonic. Results for the rotating nanofluid flow and heat tr...

In this experimental study, the performance of the diesel engine was analyzed for biodiesel derived from Calophyllum inophyllum. The impact of the addition of additives such as N-octanol and N-butanol with Calophyllum inophyllum biodiesel has been assessed. Impact of the application of hybrid N-octanol and N-butanol with biodiesel on emission profile used for the engine performance has also been demonstrated. Response surface analysis of alcohol additives-biodiesel blend was performed separately in this study for the engine efficiency and emission profile. A combination of N-octanol and N-butanol presented the highest brake thermal efficiency (BTE) and lowest carbon monoxide (CO) emission among the ternary blends of octanol. N-butanol-biodiesel blend presented the lowest hydrocarbon (HC) emission among the blends of N-butanol. N-octanol with 5 and 10% addition with biodiesel showed the lowest HC emissions among the blends of octanol. The response surface methodology (RSM) optimizati...

The objective of the work is to investigate both thermal and mechanical properties of vinyl ester/glass composites incorporated with different percentages of carbon black reinforcements through experimental approaches. Analysis of glass transition temperature, thermogravimetric analysis (TGA), degradation temperature, hardness, flexural strength, etc. is performed using differential scanning calorimeter, X-ray diffraction, tensile machine, and flexural machine, respectively. The scanning electron microscope was used for surface fracture studies. The degradation temperature reduces initially with the percentage of carbon black and then increases. Glass transition temperature increases with the percentage of carbon black while above 500°C temperature, the weight percentage of composite drops. The results also reveal that 4% of carbon with vinyl ester improved the tensile strength by 30%, hardness by 35%, flexural strength by 45%, flexural modulus by 66%, and interlaminate shear streng...

This paper mainly focuses on optimal replacement of diesel by Tyre Pyrolysis oil-Ethanol blends to run a common rail direct injection (CRDI) multi cylinder engine and to compare the results with neat diesel fuel operation results at 1500 rpm. The engine was operated at different loads and speeds. From the experimental study, decrease in brake thermal efficiency (BTE) and oxides of nitrogen (NOx) emission with increase in carbon monoxide (CO), hydrocarbon (HC), and smoke emission was observed for blends as compared to diesel fuel. Further, it was also observed that increase in speed from 1200 rpm to 1800 rpm yielded higher BTE with decrease in CO, HC and smoke emission. But slightly increase in NOx, peak pressure (PP) and heat release rate (HRR) was reported at higher speed as compared to lower speeds. Beyond engine speed of 1800 rpm, knocking was observed.

This study presents a novel application of soft-computing through intelligent, neural networks backpropagated by Levenberg–Marquardt scheme (NNs-BLMS) to solve the mathematical model of unsteady thin film flow of magnetized Maxwell fluid with thermo-diffusion effects and chemical reaction (TFFMFTDECR) over a horizontal rotating disk. The expression for thermophoretic velocity is accounted. Energy expression is deliberated with the addition of non-uniform heat source. The PDEs of mathematical model of TFFMFTDECR are transformed to ODEs by the application of similarity transformations. A dataset is generated through Adams method for the proposed NNs-BLMS in case of various scenarios of TFFMFTDECR model by variation of rotation parameter, magnetic parameter, space dependent heat sink/source parameter, temperature dependent heat sink/source parameter and chemical reaction controlling parameter. The designed computational solver NNs-BLMS is implemented by performing training, testing and...

The recent work investigates the heat transfer attributes in the flow of engine oil which comprises of nano-particles such as Cu and TiO2. The performance of Copper and Titanium oxide is over looked in the flow of engine oil. The energy equation is amended by the features of thermal radiation, viscous dissipation, and heat generation. The mathematical model signifies the porosity, entropy generation and moving flat horizontal surface with the non-uniform stretching velocity. Quasi-linearization, which is a persuasive numerical technique to solve the complex coupled differential equations, is used to acquire the numerical solution of the problem. Flow and heat transfer aspects of Cu–TiO2in the flow are examined against the preeminent parameters. The flow is significantly affected by the thermal jump conditions and porous media. It is observed here that the temperature as well as heat transport rate is reduced with the effect of involved preeminent parameters. However, such fluids mus...