BITS Faculty Publications
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Item Development and optimization of pearl millet waste biocomposite ceiling tiles: a waste management approach(Springer Nature, 2025-07) Routroy, SrikantaThe present study aims to develop and optimize sustainable biocomposite ceiling tiles by partially replacing gypsum with pearl millet waste, combined with Waste Wheat Flour (WWF) and waste paper. It aims to provide a sustainable alternative to conventional gypsum-based product, maintaining thermal insulation and flexural strength. Taguchi method was employed for experimental design, by varying key parameters such as gypsum, Pearl Millet Seed Covering (PMSC), and ceiling tile thickness. The signal-to-noise (S/N) ratio was used to identify the optimal composition and Analysis of Variance (ANOVA) with regression analysis determines the significance of each factor on thermal conductivity and flexural strength. The optimized composition for minimum thermal conductivity (0.065 W/m·K) was identified as 45% PMSC and 10% gypsum at 12 mm thickness. For maximum flexural strength (1.24 MPa), the optimal mix was 55% PMSC and 30% gypsum at 14 mm thickness. The finding underscore the critical influence of gypsum and tile thickness in enhancing material performance. The developed regression models exhibited predictive R2 value of 96.90% for thermal conductivity and 94.44% for flexural strength and an error margin below 3%, confirming the robustness of the approach. This study is original and introduces pearl millet waste biocomposites as eco-friendly alternatives to gypsum ceiling tiles. These tiles hold practical implications in ceiling, partition walls and decorative finishes across various geographic regions, contributing significantly to environmental sustainability and energy-efficient building solutions.Item A multiple regression model to analyze the impact of endogenous factors on pearl millet and stover yield in India(Emerald, 2025-08) Routroy, Srikanta; Sharma, Satyendra KumarThe purpose of the study is to explore the impact of endogenous (farmer-controlled) factors on both pearl millet and stover yield. The study uses descriptive and inferential statistics to analyze farmer-controlled factors affecting pearl millet and stover yields, based on 473 survey responses from Rajasthan’s semiarid zones, analyzed with Minitab 21.4. The descriptive results indicate widespread use of desi seeds (77.4%) and organic fertilizers (67.4%), extensive crop rotation (78%), low intercropping (12%) and extensive dependence on rainfall (70%). The multiple regression analysis indicates irrigation frequency, seed type, fertilizer type and crop rotation as major drivers of yield. The most efficient combination of hybrid seeds, inorganic fertilizers, intercropping and high irrigation frequency yields the best yields. The least efficient combination of desi seeds, no fertilizer, no intercropping and very low irrigation frequency yields low yield levels. The findings validate targeted input strategies and policy reforms.Item Assessment of risk propagation in an e-waste collection system using Bayesian networks(Springer, 2025-03) Routroy, Srikanta; Dasgupta, Mani SankarThe widespread use of electrical and electronic devices has become integral to modern life, transforming communication and day-to-day work; however, this has led to a significant challenge in effectively managing the growing volume of electronic waste (e-waste). Effective e-waste management faces a substantial challenge as the collection rates remain low, primarily due to inadequate collection systems and socioeconomic disparities. The present study investigates the assessment of various prominent risks affecting the e-waste collection system. It aims to examine the e-waste collection risk propagation categorized into social, environmental, economic, technical, and policy aspects. The Bayesian network approach is utilized to address a range of potential risks. The key findings indicate inconsistencies in the data collected on e-waste, including information such as collection date and time, location, and technical details. These inconsistencies are observed both between users or customers and e-waste collection agencies, as well as among the country's administration officials. In improving the e-waste collection system, the pivotal factors contributing to improvement were found to be technical and social risks. The insights of this study provide valuable information for policymakers to make informed decisions about promoting sustainable e-waste management practices.Item Towards sustainable transportation: factors influencing electric vehicle charging stations development(Elsevier, 2025-05) Digalwar, Abhijeet K.; Routroy, SrikantaThe Indian transportation sector, reliant on fossil fuels, is predominantly accountable for the emergence of critical challenges such as greenhouse gas emissions, reliance on foreign energy sources, economic strain, and persistent health repercussions. In order to mitigate these urgent challenges, electric vehicles (EVs) are conceptualised as a viable, sustainable and ecologically sound technological solution, capable of successfully transitioning towards a sustainable low-carbon emission transportation framework and preserving finite natural resources. EVs encounter significant challenges in achieving rapid assimilation into the commercial landscape, and one of the most frequently referenced impediments to the accelerated adoption of EVs is the insufficiency of charging infrastructure along with the resultant range anxiety. Nevertheless, expanding the charging infrastructure network is financially burdensome and necessitates careful and strategic planning. Despite identifying essential factors, the inquiry “In what manner do these factors engage and interact?” has predominantly remained unaddressed in empirical investigations. Examining the interactions between these variables will empower producers and regulatory authorities to participate in systematic planning and devise suitable measures to govern these variables. The prime objective of this research is to execute an exhaustive assessment and furnish insights into the multifaceted factors/criteria influencing the establishment and development of EV charging infrastructure within a developing nation such as India. Factors are extracted from previous studies through literature reviews and expert interviews. The study also validates the identified factors empirically. Subsequently, a mixed-method approach is utilised to implement a combination of Interpretive Structural Modeling (ISM) and Decision-Making Trial and Evaluation Laboratory (DEMATEL). This methodology enables a methodical exploration of the hierarchical structures and interconnections among the variables, thereby enhancing the comprehension of their influence on the implementation and efficacy of charging infrastructure. The study identifies technological, economic, political, geographical, environmental, geopolitical, and socio-technical factors as key drivers influencing EV charging infrastructure development, highlighting the interdependencies between critical variables and providing a structured framework to enhance accessibility, scalability, and sustainability in alignment with global Sustainable Development Goals (SDGs) 7 and 13.Item Analyzing the effects of pickling sludge and fly ash valorized cement sand bricks(Springer Nature, 2025-07) Routroy, Srikanta; Singhal, AnupamThe disposal of Stainless-Steel Pickling Sludge (SSPS) in landfills remains an important issue. Utilizing SSPS as construction material mitigates the negative environmental effects associated with its disposal, providing a sustainable solution. This study investigates co-utilization of SSPS and fly ash as partial substitution of river sand on cement sand bricks properties. Nine cement sand bricks compositions, including control mix, were prepared with varying composition of SSPS, fly ash and river sand. Four compositions were developed with SSPS varied from 2.5 to 10% with fixed fly ash content of 50%. Four additional compositions with varying fly ash content from 40 to 47.5% and varying SSPS 2.5–10% content as partial substitution of river sand were prepared. The developed bricks demonstrated that gradual increment of SSPS (2.5–10%) and reduction of fly ash (47.5–40%) proved incremental to the compressive strength up to 28 MPa. In addition, the morphological analysis using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and X-ray Fluorescence (XRF) were conducted for the compositions. The microstructure analysis showed that with inclusion of fly ash, Mix 2 (M2) compositions revealed a dense microstructure validating the sorptivity results as compared to Mix 1 (M1) compositions. Finally, the cost estimation of the waste valorized bricks as compared to the control bricks was observed to be significantly low. The experiment outcomes concluded adoption of SSPS-fly ash waste valorized bricks as a greener alternative to disposal.Item Sustainable ceramic bricks for toxic industrial waste inertization: factory scale development and characterization(Springer, 2025-07) Singhal, Anupam; Routroy, Srikanta; Bhunia, DipenduThis work reports factory-scale development of cleaner ceramic bricks with the incorporation of hazardous nickel chromium electroplating sludge (NCS) obtained during chrome-plated steel production. The NCS is particularly rich in chromium and nickel, the two metals used for chrome plating. Earlier attempts to incorporate NCS in ceramic bricks faced substantial strength reduction due to heavy metals’ presence. We engineered a high-volume incorporation of pulverised coal fuel ash (PFA) along with NCS and tested 20 compositions with varying proportion of the three ingredients. The optimum composition was obtained with 37.5% PFA, 12.5% NCS, and remaining clay soil. The optimum composition bricks witnessed substantially enhanced density and compressive strength, reduced water absorption and efflorescence. XRD analysis indicated formation of spinel structure and mullite leading to strength enhancement. SEM analysis indicated increased pore filling in brick matrix with PFA cenospheres. XRF analysis revealed appreciable presence of fluxing oxides in NCS which facilitated the sintering process. Additionally, higher amount of reactive silica and alumina in PFA led to formation of stronger ceramic bonds. Leaching tests by Toxicity Characteristic Leaching Procedure indicated negligible release of heavy metals, indicating successful immobilization of heavy metals. The developed methodology provides the relevant stakeholders an eco-friendly, economical, readily deployable scheme for eliminating the mounting NCS accumulation.Item Synergic valorization of nickel-chrome plating sludge via alkali activation of steel slag and fly ash: performance analysis(Springer, 2024-09) Lahoti, Mukund; Singhal, Anupam; Routroy, Srikanta; Bhunia, DipenduNickel–chromium plating sludge (NCPS) is a hazardous waste due to high concentration (~ 25%–30%) of chromium and nickel. Electric arc furnace slag (EAFS) is a by-product of secondary steel manufacturing through the electric arc furnace route. In this work, we valorized NCPS in an innovative ambiently cured alkali-activated NCPS-Fly ash-EAFS mortar (ANFEM). NCPS substituted the binder from 0 to 25% (by weight) in the step size of 5%. The binder composition had EAFS/fly-ash = 1.0, activator/binder = 0.45, silicate/hydroxide = 2.5. Incorporation of NCPS in ANFEM resulted in several benefits such as successful NCPS immobilization, improving the flash setting and flowability issues of alkali-activated EAFS and minimal degradation in mechanical properties. Microstructural investigation by XRD, FTIR, SEM offered insights on the underlying mechanisms of NCPS valorization and corroborated the observed results of compressive strength, water absorption, bulk density, acid resistance, and surface porosity test. At 10 wt% substitution of NCPS, ANFEM produced optimum results, such as compressive strength of 40 MPa; Wabs enhancement by 4.2%; bulk density reduction by 1.1%; and the least acid-induced deterioration. Extensive leaching tests determined leachate’s heavy metals concentration to be well-within the permissible limits. Factory scale deployment of developed methodology produced paver blocks well-satisfying Indian Standard Code 15,658: 2006.Item Modelling factors influencing charging station location selection to accelerate ev adoption in India: an ISM-MICMAC analysis(Springer, 2023-12) Digalwar, Abhijeet Kumar; Routroy, SrikantaElectric vehicles (EVs) are rising fast to prominence as a key component of the effort to meet sustainable energy goals. The research and mass manufacturing of new energy vehicles, especially electric vehicles, offer several benefits over conventional energy vehicles, such as zero exhaust emissions, zero pollution, cleanliness, and low cost. As a result, more and more nations are paying attention and placing importance over the development of EV-fleet, but EV sales are still a modest part of all vehicle sales. The protruding reason highlighted by the literature and researchers is underdeveloped charging infrastructure. To get the most out of an EV, an appropriate charging station with optimum configuration needs to be placed in a specific location with all the infrastructure to make it supportive and sustainable hotspot for EVs. This study aims to identify all the factors that needs to be considered while selecting a location for setting up a sustainable charging station for EVs in semi-urban areas. A deeper understanding of factors is explored, using interpretive structural modelling (ISM) and MICMAC analysis. A total of 17 factors are considered for the analysis which are crucial in developing the configurations for an EV charging station. The outcomes of the paper will support the policymakers to locate, determine and decide the suitable locations, and configuration for constructing EV charging stations and escalate the EV adoption.Item A data-driven framework for optimizing multi-period ev charging infrastructure deployment(IEEE, 2024-12) Digalwar, Abhijeet Kumar; Routroy, SrikantaThe rise of electric vehicles represents a transformative shift in the automotive industry, signaling the dawn of a new era of clean, sustainable transportation, but their operation requires a distributed rapid-charging infrastructure. Building such rapid charging networks is currently capital-intensive and therefore, requires careful planning and the development of the charging infrastructure must be maintained. However, infrastructure construction is not a one-off investment but a multi-period plan. A multi-period location and capacity expansion model of the charging stations will be needed. This study proposes a novel data-driven framework for deploying suitable rapid-charging infrastructure for EVs in large urban areas. This study combines an iterative clustering technique with a geographical information system analysis tool to determine the suitable regions for developing an optimized EV charging service. The analysis intends to plan a case study for Gurugram City of India and suggest the locations that should be the potential points for consideration of charging station development.Item Fired clay bricks synergistically valorizing hazardous nickel chrome-plating sludge and fly ash: Performance assessment(Elsevier, 2024-04) Singhal, Anupam; Routroy, Srikanta; Bhunia, Dipendu; Lahoti, MukundNickel Chrome Plating Sludge (NCPS) is a hazardous waste containing 25%-30% nickel and chromium. Previous attempts to immobilize NCPS into fired clay bricks resulted in weakened strength due to porosity and microstructure deterioration. This study introduces co-valorization of NCPS and fly ash in fired clay bricks to address these issues. Factory-scale firing of green bricks, alongside conventional clay bricks, assessed the commercialization potential. The optimal proportion of NCPS, fly ash, and clay was found to be as 12.5:37.5:50.0, respectively. Fly ash addition significantly improved brick properties, causing compressive strength to increase from 3.2 MPa to 11.6 MPa for a NCPS content of 12.5%. Microstructural analysis highlighted fluxing oxides in NCPS, amorphous silica-alumina in fly ash, synergistic ceramic bond formation, enhanced sintering and pore filling during vitrification. The study also demonstrated substantial fuel savings of 40%-50% due to NCPS's high heat of combustion causing internal firing of green bricks. The developed bricks exhibited almost double linear attenuation coefficients, indicating enhanced gamma radiation shielding. Leaching tests confirmed successful heavy metal immobilization. This co-valorization approach not only overcomes previous drawbacks but also offers significant environmental and economic benefits in utilizing NCPS in brick production.