Current Materials Science - Current Issue

Ultrasonic is an area of intense scientific and technological research.

Detailed study of ultrasonic parameters such as velocity paves way for study of interactions among the molecules in binary and ternary liquid mixtures. Ultrasonic velocity (u), density (ρ) and viscosity (ɳ) of the binary mixture of artificial sweetener is determined at ambient temperature.

Using these basic parameters, several acoustical parameters such as adiabatic compressibility, acoustic impedance, intermolecular free length, molar volume, free volume, internal pressure, relaxation time, Gibb’s free energy, Rao’s constant and Wada’s constant are calculated and some spectroscopic studies is done to elucidate the functional group that are present in the binary mixture.

This gives an understanding of molecular interactions. This work can be extended to many multi component solutions.

Electronic packaging makes use of hybrid A356 aluminium alloy MMCs (matrix metal composites). Enhanced endurance limit, increased production and energy, low maintenance cost, and benefits to the environment, such as reduced noise and airborne pollutants, are among the features that are recommended to be evaluated. This study aimed to analyze the thermal properties of A356 aluminium alloy with graphite (Gr) and boron carbide (B4C) hybrid metal matrix composites. For this purpose, the A356 hybrid composite was primed by the stir casting process with the addition of 5 wt % and 10 wt % of Gr and B4C reinforcements. In general, A356 hybrid composite material thermal analysis is crucial for electrical equipment.

The liquid-in-filtration method was used to create the hybrid composites, which were then tested thermally for parameters, like melting point, thermal diffusivity, and thermal coefficient of expansion. The thermocouple sensor of a calorimeter was used to examine the disparity in the composites. A thermal analysis tool called TGA was used to visually represent the relationship between a material's weight and temperature.

The temperature was found to be 300^oC at the 0.411 W/g maximum heat flow rate. Thermal conductivity is the ratio of the temperature difference divided by the area of the heat transfer from one substance to another. The thermal coefficient of expansion illustrates how a material's dimensions and weight change as temperature increases.

The proportion of the weight of the hybrid composites was found to fall with a rise in the temperature. The melting point curve of the composites demonstrated a little increase in temperature to be accompanied by a sharp increase in heat flow.

The modern Aluminium-Copper-Lithium (Al-Cu-li) based composites have a great demand in aerospace applications due to their lightweight, high strength, high stiffness, and superior mechanical properties. The present study explored the effect of reinforcements like graphite and boron carbide on the mechanical behaviour and microstructure of AA2195 composite.

The Medium Frequency Induction Furnace (MFIF) was used to fabricate the composites with two factors each at four levels ordered in Taguchi L16 orthogonal array.

The microstructures revealed that the reinforcements were distributed uniformly throughout the composite. The elemental investigation observed by X-Ray Diffraction (XRD) revealed that the formed Intermetallic Compounds (IMCs) helped in refining the microstructure and further increasing the mechanical properties.

The composite fabricated at 8% Boron Carbide (B4C) and 6% Graphite (Gr) exhibited better ultimate tensile strength, % elongation, and hardness as 190.74 MPa, 0.58, and 87.2 VHN, respectively.

The main key input variables to this optimization technique for constructing incomplete block designs are using bipartite and spanning subgraphs through numerical examples of vehicle fuel consumption and emissions. The theory of graphs plays a significant role in mathematical sciences and engineering technologies. In addition, the graph models many relations and processes in physical, biological, social, and information systems. The construction methods using Partially Incomplete Block Designs (PBIBD) with differential equations through bipartite and spanning subgraphs that predict hot stabilized vehicle fuel consumption and emission rates for different drivers using different cars are studied in this paper. The other modelling of fuel consumption and emissions have appeared as an essential tool, which helps to develop and measure vehicle techniques and to help estimate vehicle fuel consumption and emissions. This paper aims to develop an optimization technique for the construction method for incomplete block designs LSD with PBIBD(2) through vehicle fuel consumption and emissions.

An incomplete block design can be constructed using LSD statistical analysis with bipartite and spanning subgraphs. First, the method for the construction of LSD using bipartite graphs. The second method for the construction of PBIBD(m) using spanning subgraphs. The two construction methods are through numerical examples of an oil company testing five mixings of petrol for fuel efficiency and emission according to the variability of five drivers and five models of cars.

The inference of the first model of PBIBD(2) using LSD F-value of 0.08 implies the model is not significant (P-values greater than 0.05). The second model has no significant difference between petrol fuel efficiency and emissions. In the third model, there is no significant difference in fuel efficiency between different cars of petrol bunks.

Finally, it is concluded that the response variable is represented above the maximum quality scores from our fourth driver using a second car to the fourth petrol bunk in fuel efficiency.

With an aim to partially replace conventional diesel fuel, this work investigated the impact of injecting hydrogen into an intake manifold of a diesel engine on its performance. Due to the benefits of hydrogen fuel, such as its high calorific value and flame velocity, it can be used in a dual-fuel mode of operation with diesel. The experiment was carried out for various engine loads with engine speed maintained constant at 1500. By using a digital volume flow metre, hydrogen was injected at three different volume flow rates, namely 3, 6, and 9 lpm. Engine combustion, emission, and performance parameters were evaluated for different hydrogen flow rates and compared to sole diesel.

The result revealed that the brake thermal efficiency of the engine increased, whereas the brake-specific fuel consumption decreased due to hydrogen enrichment. The hydrocarbon and carbon monoxide emissions were lower in dual fuel mode when compared to sole diesel operation under all load situations.

On the other hand, Oxides of Nitrogen (NOx) emission increased with hydrogen flow rate and resulted in higher NOx than diesel. Furthermore, hydrogen enrichment increased the values of the peak heat release rate and cylinder pressure by a significant margin from the corresponding values given by diesel fuel.

Among the evaluated H2 flow rates, 9 lpm is found to be the best, demonstrating enhanced engine characteristics.

Machining hybrid composites through conventional machining technique was a challenging task as it produces excessive tool wear and exhibits poor surface roughness. In this research work, an attempt was made to electric discharge machining of AA7075/SiCP/B4CP Hybrid Composites produced through the stir casting route. The used engine oil was as the dielectric fluid with the objective of obtaining wealth from waste. The experiments were performed by varying distinct Electric Discharge Machining (EDM) process parameters with the goal of obtaining a high Material Removal Rate (MRR), low Tool Wear Rate (TWR) and least Surface Roughness (Ra). The experimental runs were optimized using the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) optimization techniques.

Experimental runs were designed using the L20 Taguchi orthogonal arrayin which Powder concentration, Current and Pulse on time were varied for three different levels, and two various dielectric fluids were used for investigation. The characteristics of the Used Engine Oil (UEO) were assessed to find its feasibility as a dielectric fluid.

In comparison to EDM oil, the specimen machined in UEO dielectric medium has a somewhat greater MRR. Regardless of the kind of dielectric fluid employed, adding Al2O3 particles increases the MRR because of the bridging effect. Due to its high thermal conductivity, UEO oil produced electrodes with a TWR that was greater than that of EDM oil. The TWR decreases with the addition of Al2O3 particles due to an increase in the spark gap. In comparison to EDM oil, the specimen machined under UEO displays a lower Ra value. Ra decreases with the inclusion of Al2O3 particles due to the thorough flushing of machining waste.

The specimen machined under Al2O3 mixed UEO dielectric medium, with the process parameters tuned at 3 A current and 20 µs Ton, offers better machining performance and was recommended for EDM sector.

Yb³⁺/Ho³⁺co-doped YPO4 nano phosphors were synthesized by polyol route, which has both up-conversion (UC) and down-conversion (DC) characteristics and excellent luminescent properties. DC peaks were seen at ~460, ~550, and ~650 nm.

Switching at ~750 with 300 nm excitation revealed a modest P-O charge-transfer (CT) band of the Ho³⁺ ion and a little non-radiative resonant energy transfer. We discovered that YPO4: Yb³⁺/Ho³⁺ is an up-converting (UC) nanophosphor capability. Large-scale creation and amplification of light through green and red emissions.

Strong laser irradiation at 980 nm results in clear up-conversion emission peaks for Ho³⁺ ions at 550 and 650 nm. This technique yields high-quality nanocrystalline materials with tens of nanometers in size. YPO4 produced high quantum yield values: Yb³⁺/Ho³⁺ when stimulation was applied at 300 nm.

This finding can be used to manufacture high-efficiency phosphors and demonstrates that the nano-phosphor materials covered by this method have a wide range of applications.

Conventional reinforced concrete mixes are used for building projects worldwide because they are strong and last longer. Due to its versatility with different admixtures and compositions, the conventional concrete mix has always been a research area. Researchers are investigating the compatibility of conventional concrete with natural fibers to inexpensively attain maximum strength in concrete, as conventional concrete adds strength by adding fibers.

In this research, the durability test, acid and alkaline attack test, and wetting and drying test are performed to evaluate the concrete mix.

The mix design for M25, M35, and M50 grade concrete with and without sisal fiber is completed in this work. Overall, findings from several analyses suggest that sisal fiber concrete outperforms conventional concrete in terms of strength and durability. According to the study, sisal fiber concrete can be used instead of conventional concrete to achieve superior outcomes and sustainability.