IR@CIMFR - Central Institute of Mining and Fuel Research (CSIR)
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Influence of Joint Orientation and Spacing on Induced Rock Mass Damage due to Blasting in Limestone Mines
No full textThe nature and orientation of joints in rock strata affect the damage pattern under explosive loading. Most of the limestone deposits in India are found with severity of joints. Categorically, these joints may have variable orientations such as dipping out of the blast face, inside the face, horizontally or having strike parallel to the face. The damage pattern under the varying category of orientation will be different. Accordingly, a numerical model in Ansys-Explicit Dynamics was prepared to compare the damages of rock mass under different joint orientations. The physical nature of a joint reflects frictional and stiffness behaviour. Accordingly, the damages have been compared under bonded and frictional nature of joints. The output damage pattern from the model has been validated on the basis of blastability index proposed by Lilly. Different limestone mines in India show different nature of jointing in their rock strata. Accordingly, the blasting outputs from three different limestone mines, viz. Rawan limestone mine, Sagmania and Birhauli limestone mine and Injepalli limestone mine, have been compared along with their blast design parameters and the nature of joint. The comparative results show that the closely spaced horizontal joints support maximum in burden movement and rock fragmentation due to blast
An Assessment on Quality of Life and Happiness Indices of Project Affected People in Indian Coalfields
No full textCoal deposits are generally found in either riverine and/or beneath forest area. The coerced displacement of project-affected people (PAPs) for coal mining endangers the in situ conservation of their life/livelihood. It accounts for a heavy price against the mineral value mostly harvested by distant stakeholders. A study on quality of life (QoL) enroute happiness indices of PAPs is undertaken with reference to CSR/resettlement and rehabilitation initiatives undertaken by mining companies in coalfields of Jharkhand. This study aims to analyze elements influencing quality of life and happiness indices such as job/income opportunity, housing affordability, health security, infrastructure, social relations, environment sustainability, inclusivity, equity and diversity. Data were collected directly from PAPs using a questionnaire survey method and almost 501 responses received to assist in development of the model. Multivariate statistical analysis has been used with application of structural equation modeling methodology for data analysis. The result shows vital relations among the constructs introduced based on human, social, natural, physical and economical concerns. The findings also indicate inadequate resettlement and rehabilitation initiatives undertaken by project proponents towards restoring life quality. Thus, the conceptual framework customized to mining area is developed and validated for rendering a qualitative life-ecosystems to the PAPs
Nanofiltration membranes composed of carbonized giant cane and Pongamia meal binder for ion sieving in water and molecular sieving in organic solvents
No full textClimate change and other environmental problems necessitate the use of renewable resources and the development of sustainable technologies. Thus, giant cane, which is naturally abundant, and a plant-based binder extracted from Millettia pinnata seeds were used to fabricate carbon-based composite membranes. A continuous and uniform layer of a carbonized giant cane was formed on a porous support using a simple filtration method. The hardness of the membranes increased with the carbon content. The increase in the carbon content in the membrane yielded a looser and more selective nanofiltration membrane; the water permeance increased from 13 to 19 L m−2 h−1 bar−1 and the NaCl/MgSO4 selectivity doubled from 10 to 20. Similarly, the rejection of five different salts and seven organic molecules decreased in water and acetone, respectively. The acetone permeance and molecular weight cutoff increased from 7 to 12 L m−2 h−1 bar−1 and from 577 to 795 g mol−1, respectively. The long-term performance tests on the membranes indicated a stable rejection of higher than 99% for rose bengal and a stable steady-state flux over a week of continuous filtration. The membranes exhibited good stability and high permeance in different organic solvents, including a harsh polar aprotic solvent, i.e., N,N-dimethylformamide. The toxicity of the giant cane carbon and the binder was examined via a cytotoxicity assay using NIH 3T3 cells. No toxicity was observed for either material. This study proposes a sustainable route for preparing aqueous and organic solvent nanofiltration membranes using natural nontoxic resources
3D-Printed Nanoscale-Thick Silver Thin Films for Electrochemical Sensing
No full textNanoscale-thick silver thin films (Ag-NTF) on indium tin oxide-coated glasses are fabricated at different deposition potentials (1.0–5.0 V) using an electrochemical three-dimensional (3D) printing process. The printing process is carried out using a nozzle with a diameter of 0.25 mm and a printing speed of 1.0 mm s–1. The X-ray diffraction (XRD) data showed that the mean crystallite size of Ag is 17 nm. The optical and field emission scanning electron microscopy (FESEM) data revealed the uniform NTF nature of the Ag-NTF electrode. Transmission electron microscopy (TEM) data showed that Ag-NTF electrode particles have a spherical shape with an average size of 21 nm. Furthermore, electrochemical surface activity study showed that samples deposited at 3.0 V have the best electrochemical activity, and hence, the same are used to develop hydrogen peroxide sensors. The sensing measurements are done using a 0.1 M phosphate buffer saline (PBS) electrolyte. The sensitivity of the Ag-NTF comes out to be 25 ± 1 μA mM–1 cm–2 with a lower detection limit (LOD) of 1.0 μM. The selectivity of the electrode is tested using various interfering chemicals. The developed sensors showed excellent selectivity toward H2O2. Finally, the applicability of the Ag-NTF electrodes toward real-life samples is shown using bovine albumin serum (BSA) and rainwater. For the first time, this study has demonstrated the use of an electrochemical 3D printing process to fabricate electrodes for H2O2 sensing. The inherent nature of the process has the capability to eliminate the conventional tedious route to make such electrodes and to provide a one-step and efficient solution
Symmetric supercapacitors based on copper–antimony chalcogenides: A trade-off between S and Se
No full textTo enable a society based on carbon-free electricity, electric energy storage is crucial. In this regard, the development of novel supercapacitors with high capacity and long cycling stability is critical as supercapacitors have a higher power density than batteries. A promising group of supercapacitors is chalcogenide-based materials as they show excellent ionic conductivity and stability. Moreover, ternary chalcogenides are earth-abundant, low-cost, non-hazardous materials, and the third constituting element can optimize the structural and electrochemical properties leading to improved performances. However, so far, only a few ternary chalcogenide-based supercapacitors have been developed. Herein, we have synthesised and characterized Cu3Sb(S/Se)4, Cu9S5, and Cu2-xSe using the same solution-based method at 150°C. We compare the electric properties of all four compounds to check their suitability as supercapacitor electrode materials. The highest capacitance and cyclic stability is found for Cu3SbS4. Notably during CV studies, very high specific capacitance of 397 F/g was recorded at 5 mV/s. Motivated by this result, a coin cell based on Cu3SbS4 is developed showing 21 F/g at a current rate of 0.5 A/g with excellent cyclic stability
Machine learning approach for the prediction of mining-induced stress in underground mines to mitigate ground control disasters and accidents
No full textThe bord and pillar method is commonly employed in Indian underground coal mines, and the extraction rate varies between 30 and 65%. During pillar extraction, pillars are subjected to severe stress conditions. Due to this, the natural state of stress equilibrium is disturbed, resulting in severe strata control problems leading to sudden, unpredictable failure such as a premature collapse of pillars, severe roof or side fall, and sometimes leading to serious/fatal injury or burial of machinery. This paper deals with the prediction of mining-induced stress during pillar extraction using Machine Learning (ML) techniques like Random Forest and Multilayer Perceptron. The various factors used for the formulation of the models for predicting the mining-induced stresses are Depth of the workings (H), Panel width/length (W/L), Pillar width/working height (w/h), Goaf length, and Area of extraction. This paper highlights the importance of operational parameters rather than geological parameters. The Correlation coefficient (R2) of mining-induced stresses for the case studies discussed in the paper is 0.85 for Random Forest and 0.76 for Multilayer Perceptron, which shows Random Forest results have a comparative edge over Multilayer perceptron. With this developed prediction models, the stress conditions of pillars can be predicted
Assessing the non-wettability and sustainability of cellulosic jute for roadway applications
No full textDuring the last decade, the usage of geotextiles has tremendously grown into a needful auxiliary, particularly regarding soil protection. Although geotextiles made of natural fibers blended with synthetic materials are considered a modern achievement, backing up the basic concept of increasing the stability of roads and soils, they suffer from severe degradation. It includes the environmental exposure such as hydrolysis, and thermal, chemical, and biological degradation, affecting their long-term performance. This paper focuses on the jute-based geotextile having outstanding water repellency with a water contact angle of 169° and immutable tensile strength (~ 12 MPa) when incorporated with hexadecyltrimethoxysilane (HDTMS) modified titanium dioxide (TiO2) nanoparticles (nps) via drop casting technique. Herein, the durability of the coating was examined by sand (dropping sand particles) and impact (driving two-wheeler) tests on the coated jute sample. In addition, the coated samples were immersed in different aqueous mediums, and the behaviour in the tensile strength was noted. Similarly, the thermal degradation affecting the tensile strength was also evaluated. Lastly, biodegradability was judged by burying the samples for different periods in the soil. These outcomes demonstrate the potential of the HDTMS-TiO2 nps coating on jute geotextile having a suitable mechanically durable and sustainable superhydrophobic property that could be successfully used in roadway applications
A Review of Factors Affecting Gasifier Performance
No full texthe Physico-chemical characteristics are inherent properties of fuel and their behaviour changes in different gasification conditions. The critical properties of the coal impede the gasifier's performance, and hence, a proper study is needed to develop and further enhance the gasification systems. A proper assessment of factors influencing gasifier performance and their optimization enables to select, alter, and adjust the conditions. The present paper reviews the effect of important coal properties and gasifier operating conditions on gasification performance parameters. Further, the suitability of gasifiers (moving bed, fluidized bed, and entrained flow) according to the physico-chemical properties of fuel along with proper operating parameters has also been studied
Elucidation of furanone as ergosterol pathway inhibitor in Cryptococcus neoformans
No full textIn the era of antiretroviral therapy, the prevalence of Cryptococcal infection among HIV patients in developed countries has decreased considerably. However, C. neoformans ranks top among the critical priority pathogen that affects a wide range of immunocompromised individuals. The threat of C. neoformans is because of its incredibly multifaceted intracellular survival capabilities. Cell membrane sterols especially ergosterol and enzymes of its biosynthetic pathway are considered fascinating drug targets because of their structural stability. In this study, the ergosterol biosynthetic enzymes were modeled and docked with furanone derivatives. Among the tested ligands Compound 6 has shown a potential interaction with Lanosterol 14 α-demethylase. This best-docked protein-ligand complex was taken further to molecular dynamics simulation. In addition, Compound 6 was synthesized and an in vitro study was conducted to quantify the ergosterol in Compound 6 treated cells. Altogether the computational and in vitro study demonstrates that Compound 6 has anticryptococcal activity by targeting the biosynthetic pathway of ergosterol.
Communicated by Ramaswamy H. Sarm
Effect of Temperature on physic-mechanical properties of Chunar sandstone, Mirzapur, U.P., India
No full textIn this paper, the effect of elevated thermal treatment on the physico-mechanical parameters of Chunar sandstone from Mirzapur district of U.P. was investigated. The studied area is represented geologically by the Vindhyan Supergroup from Meso to Neproterozoic age. Sandstone of Chunar area, Mirzapur, U.P. has been granted the tag of Geographical Indication (GI) under the category of natural goods in 2019. Mechanical strength tests (indirect tensile and uniaxial compressive strength) were performed by a universal testing machine. Samples were treated at elevated temperature in the electric furnace at different temperatures for conducting mechanical and physical tests in each sample and results were recorded. The results suggest that for sandstone, high temperature treatment leads to volume expansion, weight reduction and a decrease in density as well as the reduction in the strength characteristics. Up to 200 °C there is an inappreciable increase in indirect tensile strength and compressive strength but after 200 °C strength gradually decreases. Beyond 400 °C, the P-wave velocities showed a sharp decline due to elevated temperature treatment induced cracks in the heated sandstone