Indian Journal of Engineering and Materials Sciences (IJEMS)

Processing of ochre from Daitari Iron ore mines, Singbhum Craton, Eastern India for optimum utilisation

2025-04-17T22:06:05+0530

Ochre, a naturally occurring powdery material, has been commonly appeared associated with different iron ore morphotypes in many iron ore deposits of the Singhbhum Craton, eastern India. It has appeared in yellow, red, gray and black colours. The present paper has described the characteristics of ochre occurring in the Daitari Iron Ore Mines in Odisha, India, and has discussed its processing for sustainable iron making and optimum utilization. Usually, ochre shows poor iron value, fine size and therefore being considered as a waste. However, in the present set-up, the ochre sample has shown ~60% Fe, 4% combined Al₂O₃ + SiO₂ and ~10% LOI, contributed by hematite, goethite and limonite phases. Though compositionally it appears to be a good candidate for iron making, it has remained unsuitable as blast furnace feed due to its fine particle size and high LOI content.
Attempts have been made to convert this powdery ochre to a lumpy form by adopting the pelletization technique. The sample below 150 μm size has been mixed thoroughly with three different charge mixes (bentonite, limestone and coke fines) and pellets have been prepared in a laboratory-scale disc pelletizer. Three sets of samples have been prepared with variable bentonite contents (0.5, 0.75 and 1%) keeping fixed limestone and coke amount. The green pellets from the pelletizer have been exposed to drop test and Green Compressive Strength (GCS), followed by thermal indurations at 1100, 1200 and 1300 °C. The porosity (%) and Cold Crushing Strength (CCS) (kg/pellet) of the indurated pellets have shown variations at three different temperatures. Pellets prepared with 1% bentonite content and indurated at 1300 °C have given 22% porosity and 255 kg/pellet CCS. XRD, optical and electron microscopy studies have revealed that recrystallization of hematite during induration has enhanced pellet strength and properties, while fayalite and calcium ferrite formation has provided stability through slag bonding. Pellets indurated at 1300 °C have shown Fe enrichment from ~60% to ~67% with ~3.2% combined Al₂O₃ + SiO₂, making them suitable as blast furnace feed. If this technique is applied, an appreciable
quantity of ochrous waste accumulated at mine sites can be converted to wealth.

Innovations in water quality management using machine learning approaches

2025-06-21T02:50:01+0530

Groundwater contamination has been posing a significant threat to sustainable water resource management, particularly in industrialized and urbanized regions. This research has introduced a novel, data-driven framework that integrates machine learning, statistical data analysis, and feature optimization to evaluate and forecast groundwater quality. Analytical results of 488 groundwater samples had been tested, and four feature reduction scenarios had been implemented using Pearson correlation to evaluate predictive performance with minimal input variables. Statistical analysis has highlighted elevated levels of parameters such as Electrical Conductivity, Chloride, Magnesium, and Total Hardness, exceeding permissible limits, and have been causing most samples to be unsuitable for consumption without treatment. To enhance groundwater monitoring and reduce laboratory testing costs, six machine learning algorithms, K-Nearest Neighbors, Support Vector Machine, Decision Tree, Random Forest, XGBoost, and Artificial Neural Network, have been used to predict the Weighted Arithmetic Water Quality Index. Model accuracy had been tested using statistical metrics such as R², RMSE, MAE, MAPE, and CRMSE, with effectiveness assessed using Taylor diagrams. ANN exhibited the highest accuracy even when using a single input (K), while SVM maintained consistent reliability with only two inputs (Mg and K), providing a cost-effective monitoring solution. Validation with 70 independent datasets has confirmed the robustness and applicability of the
suggested methodology. The study has presented an innovative modeling strategy that has substantially decreased laboratory testing needs while preserving predictive reliability. Additionally, it has offered practical implications for scalable, cost-effective deployment in areas with water scarcity or insufficient datasets.

Rutting and fatigue performance of high-dosage crumb rubber modified bitumen

2025-08-22T12:00:51+0530

This study investigates the effects of crumb rubber (CR) modification on the rheological and performance characteristics of asphalt binders, with a focus on rutting and fatigue resistance. Modified binders were prepared with CR contents 10%, 15%, 20% and 24% by weight of viscosity grade-30 (VG-30) binder. These binders were evaluated using Dynamic Shear Rheometer (DSR), Multiple Stress Creep Recovery (MSCR), Zero Shear Viscosity (ZSV), Shenoy parameter, and the Linear Amplitude Sweep (LAS) test. The addition of CR significantly increased the complex shear modulus (G*) and storage modulus (G′) by up to 3.1 and 30.3 times respectively, while reducing the phase angle (δ) by up to 34.6°, indicating improved stiffness and elasticity. Enhanced values of G*/sin δ and Shenoy parameter increased by 5.34 and 10.4 times respectively for CR24 binder demonstrating improved rutting resistance. MSCR results showed percent recovery increased from -0.2% to 75.1%, and non-recoverable creep compliance (J_nr) decreased from 2.81 to 0.07 kPa⁻¹. The Rutting Resistance Index Ratio (RRIR) was effective in evaluating crumb rubber modified bitumen (CRMB) performance with J_nr showing the highest sensitivity to CR content, establishing it as robust indicator of rutting resistance. Fatigue analysis revealed that the binder with 20% CR offered the best balance between fatigue resistance and strain tolerance, identifying it as the optimal dosage. A strong inverse correlation with r-square value 0.91 was found between elastic recovery (ER-DSR) and Jnr, and a moderate positive correlation with r-square value 0.68 between ER-DSR and fatigue life (N_f), highlighting the interconnected nature of elasticity, rutting resistance, and fatigue performance.

Comparative assessment of airport pavement condition using PCI and ACN-PCN methods

2025-02-11T14:59:37+0530

A scientific approach is essential for evaluating pavement surface conditions at the network level. The prime objective of airport pavement in terms of functional condition analysis is to focus on the current and future pavement conditions. The Pavement Condition Index (PCI) is a well-known method widely used to assess the surface conditions of airport pavements. The aircraft movement from the Runway while take-off and landing or taxiing at the taxiway and parking at aprons induces a high magnitude of repetitive loads that create excessive stresses due to which pavement layers are affected and distress appears on the surface of the pavement sections. This study computed the analysis of the distress and traffic measurement to evaluate pavement condition index (PCI), Structural condition index (SCI), and FOD index. In addition, the aircraft classification number and pavement classification number (ACN/PCN) methods were applied to all sections of airport branches to estimate the structural bearing capacity of the airport pavement network. By adopting the traditional method of the PCI, the relationship between the pavement condition index and pavement classification number was studied. Finally, based on the combined rating index, a treatment methodology was proposed for the improvement of the existing critical pavement section by using a decision tree (DT).

Electrification and its influence on trip rates and vehicle choice in urban freight - Case study of Delhi

2025-07-09T13:19:16+0530

The rapid electrification of goods vehicles in India, particularly in urban centers like Delhi, is transforming last-mile freight dynamics. This study analyzes the impact of electrification on trip rates and vehicle choice within Delhi’s urban freight sector. Using Parivahan registration data, trip rates from the trip generation study, and vehicle count surveys, we examine the shift from traditional light commercial vehicles (LCVs) toward electric goods three-wheelers (3WTs). The findings reveal a significant rise in 3WT registrations and trip frequencies, alongside a relative decline in LCV usage. The project sales of 3WT segment shows a steady rise from around 12,500 in 2025 to over 20,000 units by 2030, while the sales of LGV decline to 11,000 by 2030. Key drivers of this modal shift include operational advantages, less restriction on EV’s entry timings, and supportive government policies promoting electric vehicle adoption. These insights highlight the changing nature of freight mobility in Indian cities and suggest strategies to further support sustainable urban logistics.

Evaluating the performance of soil nailing in slope stability under complex conditions

2025-06-25T03:05:48+0530

Soil nailing has become a widely adopted slope stabilisation technique designed to enhance the structural integrity of soil and rock masses, particularly in earthquake and landslide-prone regions. It has effectively stabilised both natural and man-made slopes by preventing erosion, settlement, and various forms of slope failure, while also reinforcing existing foundations, etc. In this paper, to investigate the effect of soil nailing on slope stability, a two-dimensional finite element method (2D-FEM) was utilised to simulate four distinct slope conditions: Case-I (no surcharge, no nails), Case-II (surcharge without nails), Case-III (surcharge with nails), and Case-IV (nails without surcharge). This study has introduced a numerical framework that examines plastic equivalent deviatoric strain, plastic strain along the x- and z-planes, and plastic shear strain to comprehensively assess displacement behaviour under varying conditions. The results have shown significant reductions in displacements along the x-direction (d_x), z-direction (d_z), and the resultant displacement magnitude (|d|), particularly in Cases III and IV. Furthermore, the analysis has taken into account several environmental conditions: (A) without groundwater table (GWT) and seismic loading, (B) with GWT but without seismic loading, (C) without GWT but with seismic loading, and (D) with both GWT and seismic loading. Across all scenarios, the incorporation of soil nails significantly improved the factor of safety (FOS), whereas increasing the slope angle from 30° to 90° relative to the horizontal plane correspondingly decreased the FOS, indicating a critical balance between slope inclination and stability. Overall, this study has demonstrated the effectiveness of soil nailing in enhancing slope resilience and has provided comprehensive insights into its performance under diverse environmental and loading conditions.

Numerical investigation for performance evaluation of In-filled materials in vibration screening

2025-05-01T10:53:42+0530

Surface vibrations caused by human activities such as industrial activities, plying of high-speed traffic(e.g. on highways and
railways), piling and blasting during construction and demolition works usually reach limits where they have become problematic for people and buildings. Very often, it even reaches dangerous limits where they are no longer safe for human life. So many solutions have devised to mitigate the effects of vibration, and one of them is vibration screening by the construction of trench wave barriers. This paper has focused on evaluating the screening efficiency of in-filled materials and the impact of different parameters of trench wave barriers on efficiency. This paper has presented a numerical study and subsequent validation, a 3D finite element study of vibration screening in PLAXIS-3D against stationary surface vibrations using a trench wave barrier filled with an elastic, isotropic, homogeneous half-space. Key parameters have determined and studied thereof. The results of the numerical and experimental study have found in close agreement

Sustainable dielectric substrate for microstrip patch antennas: A comparative analysis

2025-06-14T17:25:34+0530

In this paper, a valuable evaluation of four common substrate materials Rogers RT5870, PTFE, PEC, and FR4 will be presented in combination with the microstrip patch antennas at the frequency range of 2–3 GHz. As environmental sustainability in electronic design becomes more and more popular, the paper discusses the RF performance of every substrate in terms of return loss (S11) and voltage standing wave ratio (VSWR), as well as its environmental sustainability in terms of measures like recyclability, material toxicity, and lifecycle footprint. The analyses in simulation by using CST Studio Suite 2023 will bring the fairness of all materials. The PTFE and Rogers RT5870 also perform better in RF, but FR4 also has a reasonable RF performance at a lower cost, hence it can be used in low-cost designs. PEC is a theoretical standard that is not practical to implement in reality. The outcomes underscore the necessity to have a balanced performance and sustainability that will help in the development of green electronics and an environmentally friendly antenna system.

Probabilistic analysis of cracking moment of ferrocement flexural members

2025-07-10T23:20:56+0530

Characteristic cracking moment equations for the design ferrocement flexural members are proposed. These are derived based on the results of a detailed Monte Carlo simulation (MCS) studies. In simulation, the strengths of cement mortar and reinforcement and, dimensions of reinforcements and ferrocement members are considered as random variables. The preliminary cross-sections considered for MCS are of realistic dimensions and are those of 37 ferrocement flexural members. The probability density functions of ultimate strengths of weld mesh and steel bars, required in MCS, are determined from the uni-axial tension tests on 187 weld mesh bars, 200 specimens of 4 mm diameter and 80 specimens of 6.8 mm diameter steel bars. Two deterministic equations, proposed earlier by the authors, are used in MCS. It is noted that the statistical variations in compressive strength of cement mortar has significant effect on coefficient of variation of cracking moment, and that the cracking moment follows a normal distribution at 5% significance level. A more rational equation is derived for cumulative distribution function of cracking moment and it satisfies the condition that cracking moment can not be negative. A detailed review of literature on strength and behaviour of ferrocement flexural members is included as supplementary material.

Asymmetric Magnetoresistance and Topological Hall Effect in MnZnSb single crystal

2025-08-07T14:47:10+0530

The realization of advanced spintronic phenomena in bulk materials offers a robust alternative to complex thin-film heterostructures. This study investigates the low-temperature magnetic and magnetotransport properties of bulk single-crystal MnZnSb, a ferromagnet with a Curie temperature (T_C) of ~315 K. Comprehensive characterization reveals a complex magnetic ground state below 150 K, defined by the coexistence of ferromagnetic (FM) clusters within an antiferromagnetic (AFM) or weak ferrimagnetic (WFRI) matrix. This state, stabilized by intrinsic features such as antisite disorder and kinetic arrest, creates a network of internal magnetic interfaces. Consequently, the material exhibits a pronounced spin-valve-like magnetoresistance (SVMR), an effect exceptionally rare in bulk systems, driven by spin-dependent scattering across these interfaces. Concurrently, we uncover a significant topological Hall effect (THE), with a topological Hall resistivity ( ) of ~440 nΩ cm at 5 K, contradicting earlier reports of its absence. The SVMR and THE are presented as complementary transport signatures of the non-trivial spin textures arising from the material's intrinsic magnetic inhomogeneities. These findings demonstrate that complex, heterostructure-like spintronic functionalities can emerge from phase competition in a single bulk material, opening new avenues for device design.