Global NEST Journal

Green sand moulding uses silica sand for metal casting. Silica sand mining and delivery to foundries destroy the ecosystem, making metal casting unsustainable. Due to increased sand-casting output and massive civil buildings in India, the silica sand supply is declining. The depletion and shortage of silica sand necessitate the search for viable replacements. Industrial solid waste from large-scale industrialization pollutes land, air, and water. In order to use industrial waste in large amounts, an attempt is made to use it as a replacement for natural resources. The main objective of this research is to reduce the consumption of silica sand in the foundry mould-making process. Silica sand is replaced with industrial solid waste, cupola slag, and construction solid waste sources like spent fire bricks and quarry dust, up to a considerable amount, to save the natural resources. Utilization of solid waste material in the mould-making process will reduce production costs and environmental pollution, like dumping solid waste materials on land. Sand tests like permeability, green compression strength, dry compression strength, and compactability were conducted to assess the moulding properties of these alternative moulding materials. The process parameters considered for this investigation were the percentage of bentonite binder and the percentage addition of alternative mould materials with silica sand. The various sand tests showed that 40%, 30%, and 20% of quarry dust, spent fire bricks, and cupola slag, respectively, will adequately replace silica sand for mould making. A bentonite binder of 8% is suitable for quarry dust mould, and a 10% bentonite binder is required for spent fire brick particles and cupola slag to yield better results. Aluminium castings were produced at the optimal mixture of these solid waste particles and silica sand. The results of mechanical tests such as hardness, tensile, and impact tests are comparable to those of silica sand castings.

The paper attempts to discover a city's global, direct beam, and diffused solar radiation with the help of known solar radiation of its neighbor(s). Two distinctive architecture have been used to find the solar radiation of a city. In the first architecture, we used single input and a single hidden layer of the neuron to find the solar radiation of the city. The solar radiation of Lahore, Multan, and Quetta was found via the solar radiation of Karachi. In the second architecture scheme, we used three inputs and ten neurons' hidden layers to find the solar radiation of a city in the region bounded by three cities lying at the vertices of a triangle. Multan was assumed as such an area; its neighboring cities, Lahore, Quetta, and Karachi, form a triangle, and Multan lies inside the triangle area. In both architectures, three types of solar radiation, DSR, BSR, and GSR, were found with an accuracy of 99.8 %. The coefficient of determination in each case was 0.99. It shows that the results obtained through ANN models agree well with the known values.

The effectiveness of biochar as a soil conditioner is depended on the feedstock type and pyrolysis conditions as these two factors determine its physical and chemical properties. Wheat straw was heated at two temperatures: a) 2500C and b) 5000C for two time periods: i)20 min and ii) 60 min to produce four types of wheat biochar (WB) (WB250/20, WB250/60, WB500/20 and WB500/60) that were added at two different textured soils, a sandy and a loamy one. We studied C mineralization and changes of the structural quality of the two soils. Incomplete carbonization of WB250 resulted in higher C mineralization in both soils. WB250 decomposed more intensely in the sandy soil while decomposition of WB500 was not affected by soil texture or duration of pyrolysis. Biochar addition reduced the cohesiveness of the loamy soil. WB500 enhanced the formation of smaller aggregates while pyrolysis time had no effect. None of the four types of biochar altered the aggregate size distribution of the no cohesive sandy soil. Biochar with longer pyrolysis time enhanced aggregate stability of both soils because of its higher C contents and EC that promote aggregating mechanisms. WB500/60 resulted in reduced clay dispersion in both soils.

In recent years, geotechnical engineers preferred environmentally friendly and sustainable techniques to improve the engineering characteristics of expansive soil. This paper focuses on the comparative study of the enhancement in engineering properties of expansive soil using lime and waste eggshell powder. A series of laboratory tests such as Unconfined Compressive Strength Test, pH test, Free swell Index Test, Swelling Pressure Test, California – Bearing Ratio test and Atterberg’s limit test were performed for evaluating the engineering behaviour of expansive soil with lime and waste eggshell both individually and together. The experimental test results showed that the combined admixtures significantly improve the engineering characteristics of the soil. The maximum value of compressive strength at the inclusion of 9% lime and 12% waste eggshell powder was observed to be 306 kPa. The swell pressure of the treated soil showed up to a reduction till 2.32 at the inclusion of 3% lime and 12% waste eggshell powder. In all the tests, the combined admixtures exhibited greater efficiency when compared to individual inclusion of lime and waste eggshell. Thus, the investigation results confirmed the efficient use of lime and waste eggshell powder at optimum percentages as soil-stabilizing material and made them suitable for field applications.