Fracture behaviour of fly-ash filled FRP composites

The major objective of this study was to determine the fracture toughness and fracture surface energy of epoxy, epoxy/fly-ash, epoxy/carbon fibre, epoxy/carbon fibre/fly-ash, epoxy/glass fibre and epoxy/glass fibre/fly-ash composites. The quality of composite specimens was evaluated by the ultrasonic method. The results show that a fly-ash particle can arrest the crack path and thus improve the fracture properties of fibre reinforced plastic (FRP) composites. The results of this study have further significance in view of the fact that fly-ash powder is far cheaper than carbon fibre, glass fibre and epoxy resin.     

A figure of merit for evaluating sustainability of renewable energy systems

For grading different types of renewable energy based electricity generation systems, a figure of merit has been proposed and evaluated. The figure of merit has been obtained by analyzing total energy utilization in constructing and installing the systems and by their respective electricity generation. The gross carbon emission has also been estimated for evaluation of figure of merit. This figure of merit clearly indicates that wind power is the most sustainable source for electricity generation, followed by small hydropower and solar photovoltaics.     

Multi-electrode microbial fuel cell (MEMFC): A close analysis towards large scale system architecture

Microbial fuel cells are capable of producing electricity through the treatment of wastewater, however, the low power density poses main hurdles towards their wide application. In present work, microbial fuel cell based on multiple anodes, acting as baffle is constructed for achieving higher performance which can be scaled up for real life application. It is investigated for continuous sixty two days using distillery wastewater (WW) in three batches under ambient condition. During first batch, the WW is maintained under stagnant condition inside the anode chamber where as in the rest of the two batches WW is recirculated in the chamber. A maximum power density 427 mW m⁻², is achieved under stagnant condition which is further enhanced to 597 mW m⁻² under recirculation mode. Recirculation of WW reduces the internal resistance arising from the mass transfer by 50%. Maximum COD removal and Coulombic efficiency obtained is 43% and 23%. Biofouling on the surface of the membrane facing anode chamber is observed.     

Experimental and thermal analysis of energy efficient novel design wet cooling towers

Waste heat is generally dissipated from process water to atmospheric air in cooling towers. In the present study, a novel design is used to extract more amount of heat without any additional energy input by incorporating secondary ambient air in an induced draft wet cooling tower. In addition, more fresh air is induced in the tower from the rain zone, which increases the effectiveness at any value of the water to air flow rate (L/G ratio). Moreover, tower characteristics, range, and evaporation loss were also increased due to the novel design. It is noteworthy that secondary fresh air increases effectiveness, heat rejection, and tower characteristics by 10.12%, 19.65%, and 26.11%, respectively, and decreases approach by 16.32% at 0.55 L/G ratio, 44°C inlet water temperature, 29.7°C dry bulb temperature, and 18.4°C inlet air wet bulb temperature.     

Orientation-Dependent Developments in Misorientation and Residual Stress in Rolled Aluminum: The Defining Role of Dislocation Interactions

Orientation-dependent developments in misorientation and residual stress, in rolled aluminum, were quantified experimentally and simulated numerically. The latter involved analysis using a crystal plasticity finite element model, accounting for anisotropies in slip system hardening but neglecting near-neighbor interactions, and discrete dislocation dynamics of the single crystals. Both were successful in capturing the experimental patterns of orientation dependence. Numerical simulations, without slip transfer across the neighboring grains, thus established the defining role of dislocation interactions in establishing orientation-sensitive microstructural evolution.     

Corrosion inhibition behaviour of thiourea derivatives in acid media against mild steel deterioration: An overview

This paper summarizes the inhibitor activity of various reported thiourea derivatives in acid media used against the deterioration of mild steel. Acid solutions have been extensively employed in manufacturing and many industrial processes for pickling and removal of undesirable scale. Mild steel is highly susceptible to corrosion in such aggressive acid media. The additives such as inhibitors are widely employed in those cases to reduce the extent of corrosion as much as possible. The survey of literature on organic inhibitors clearly indicates the potential usage of thiourea derivatives as inhibitors of mild steel corrosion. The influence of physical-chemical properties on the inhibition activity of thiourea derivatives has been discussed. This information is highly useful for different industrial applications where good performing inhibitors are being required for protecting mild steel from aggressive acid media.     

Effect of 200 MeV Ag ion irradiation on structural and electrical transport properties of Fe3O4 thin films

Thin films of Fe₃O₄ have been deposited on single crystal MgO(1 0 0) and Si(1 0 0) substrates using pulsed laser deposition. Films grown on MgO substrate are epitaxial with c-axis orientation whereas, films on Si substrate are highly 〈1 1 1〉 oriented. Film thicknesses are 150 nm. These films have been irradiated with 200 MeV Ag ions. We study the effect of the irradiation on structural and electrical transport properties of these films. The fluence value of irradiation has been varied in the range of 5 × 10¹⁰ ions/cm² to 1 × 10¹² ions/cm². We compare the irradiation induced modifications on various physical properties between the c-axis oriented epitaxial film and non epitaxial but 〈1 1 1〉 oriented film. The pristine film on Si substrate shows Verwey transition (T_V) close to 125 K, which is higher than generally observed in single crystals (121 K). After the irradiation with the 5 × 10¹⁰ ions/cm² fluence value, T_V shifts to 122 K, closer to the single crystal value. However, with the higher fluence (1 × 10¹² ions/cm²) irradiation, T_V again shifts to 125 K.     

Dynamic shovel allocation approach to short-term production planning in open-pit mines

The complexity and uncertainties associated with mining operations often lead to deviations from short-term plans. A proactive approach will predict such deviations and help minimise opportunity losses, providing economic and operational gains. This paper presents an optimisation tool as a dynamic shovel allocation decision-maker for mining operation simulation models. The objectives of the optimisation tool are to provide shovel allocations to mining faces in order to maximise production, meet desired head grade and tonnage at the crushers, and minimise shovel movements. This paper presents the development and implementation of the optimisation tool with an iron ore mine case study.     

A numerical approach for a comparative study of laser drilling process under single and repetitive pulse

An axisymmetric model is developed to study laser drilling process under a single pulse as well as repetitive laser pulse. The laser pulse irradiated on the surface of the workpiece is volumetric and Gaussian in nature. The laser irradiated surface is subjected to convective‐radiative boundary condition while rest of the surfaces are insulated. Finite volume method is used to discretize the domain under consideration. The resulting algebraic equations are solved with the help of the tridiagonal matrix algorithm to find temperature distribution throughout the domain. The enthalpy‐porosity method is used to track the solid‐liquid interface generated during the laser melting process. Convective heat transfer occurs inside the generated melt pool. The current model is first used to validate the results of the existing literature and as the results agreed well, further studies are made to find out the advantages of using repetitive laser pulse over single pulse laser source for laser drilling process for the same laser energy and total heating duration. Vaporization has been avoided during the process and metal removal occurs through melting only. The present numerical model can provide some insight for practical laser drilling process.