IR@CIMFR - Central Institute of Mining and Fuel Research (CSIR)
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Comprehensive advances in the synthesis, fluorescence mechanism and multifunctional applications of red-emitting carbon nanomaterials
No full textRed emitting fluorescent carbon nanomaterials have drawn significant scientific interest in recent years due to their high quantum yield, water-dispersibility, photostability, biocompatibility, ease of surface functionalization, low cost and eco-friendliness. The red emissive characteristics of fluorescent carbon nanomaterials generally depend on the carbon source, reaction time, synthetic approach/methodology, surface functional groups, average size, and other reaction environments, which directly or indirectly help to achieve red emission. The importance of several factors to achieve red fluorescent carbon nano materials is highlighted in this review. Numerous plausible theories have been explained in detail tounder stand the origin of red fluorescence and tunable emission in these carbon-based nano structures. The above advantages and fluorescence in the red region make them a potential candidate for multi functional applications in various current fields. Therefore, this review focused on the recent advances in the synthesis approach, mechanism of fluorescence, and electronic and optical properties of red-emitting fluorescent carbon nanomaterials. This review also explains the several innovative applications of red-emitting fluorescent carbon nanomaterials such as biomedicine, light-emitting devices, sensing, photocatalysis, energy, anticounterfeiting, fluorescent silk, artificial photosynthesis, etc. It is hoped that by choosing appropriate methods, the present review can inspire and guide future research on the design of red emissive fluorescent carbon nanomaterials for potential advancements inmulti functional application
Numerical investigation on structural stability and explicit performance of high-pressure hydrogen storage cylinders
No full textHydrogen, a clean and renewable energy fuel is termed the fuel of the future. Although the production of hydrogen is well-established, its storage is a major concern. The conventional metallic cylinders are bulky and cause difficulties in transportation and long-term sustenance, calling for the exploration of alternatives that are durable, lightweight and easy to fabricate. Composite high-pressure cylinders appear to be a promising solution for the storage of gaseous hydrogen. In this work, weight optimization of Type 1, Type 3 and Type 4 cylinders have been performed using lightweight materials such as Titanium, Acrylonitrile Butadiene Styrene (ABS) and Carbon fibre. The stability of these cylinders has been confirmed via structural analysis. In addition, explicit analyses such as drop and crash tests have also been carried out to evaluate the performance of the cylinder. Type 1 shows the least deformation, however, failed both the crash as well as drop tests. Whereas, the type 4 cylinder exhibits better performance in both structural and explicit simulations and is 39.2% lighter than the Type 1 cylinder. Such type 4 cylinders can revolutionize the energy storage sector and can advance mobility to a great extent in the near future
Systematic Pore Characterization of Sub-Bituminous Coal from Sohagpur Coalfield, Central India Using Gas Adsorption Coupled with X-ray Scattering and High-Resolution Imaging
No full textPore characterization helps to estimate the coalbed methane recovery and carbon storage potential of the reservoir. Earlier research on the characteristics of coal pores has shown that coal has high hydrocarbon storage potential in the adsorbed state, but few studies have shown the influence of chemical heterogeneities and depth on the adsorption potential of the coal. With the objective of studying the effect of chemical variation, depth, and surface roughness on gas adsorption potential, this study combines coal composition analysis and adsorption-based pore characterization of coal and shale samples coupled with high-resolution imaging and X-ray scattering measurements. Variation in pore features is correlated with varying depth and composition. A decrease in the mesopore volume and surface area is observed with an increase in the depth and total organic content and inverse behavior is observed for micropores. Scanning electron microscopy images depict the change in the pore shape from semi-spherical OM pores to elongated pores with depth, and samples with high mineral content show a dominance of inter- and intraparticle pores. Fractal dimension values estimated from SAXS are notably higher than N2-LPGA-derived values (i.e.,─DS > DN) due to the incorporation of inaccessible pores, which reflects an increase of up to 62% in SAXS estimated mesopore volume and surface area. This study will provide a better approach to understand the impact of composition, depth, and surface roughness over the gas storage potential in coal reservoirs
Facile Synthesis of Crystalline Molybdenum Carbide (Mo2C) Nanoparticles Coupled with a N-Doped Porous Carbon Sheet: A Synergistic Effect on the Electrocatalytic Hydrogen Evolution Reaction
No full textMo2C is a unique material due to its tunable phase and electronic structures. Because of the interaction of molybdenum and carbon, the D band of molybdenum atoms expands, similar to Pt. This hybridization minimizes the energy required for hydrogen adsorption, thereby enhancing the electrocatalytic characteristics. In this article, we report the direct one-pot synthesis of Mo2C on N doped on a porous carbon sheet for electrocatalytic hydrogen evolution reactions using ammonium molybdate as a molybdenum source, glucose as a carbon source, and ammonia as a nitrogen source. The porosity and Mo2C nanostructure embedded in N-doped carbon have helped to facilitate the infusion of electrolytes and the detachment of hydrogen molecules from the surface of a Mo2C-N-doped porous carbon sheet. Besides, the prepared composite has shown the most efficient HER performances with the overpotential and Tafel slope of Mo2C and Mo2C-NC mA/cm2 being 133 and 95 mV and 76 and 69 mV dec–1, respectively; it also has excellent stability in an acidic medium. Because of its easy resource, simple preparation, and excellent performance, the prepared Mo2C on a N-doped carbon sheet has a significant potential to be an alternative for cost-effective hydrogen production
Advances in polymer-based nanocomposite membranes for water remediation: Preparation methods, critical issues and mechanisms
No full textMembrane technology is a growing tool for contaminants removal from polluted water. Although various types
of polymeric membranes have been developed for water remediation, the common drawbacks like fouling,
hydrophobicity and low mechanical strength are yet to be suitably addressed. Most of the research is directed
towards the development of polymer nanocomposites viz., incorporating different nanomaterials into polymer
matrices enhancing bare polymer matrices’ properties. In this paper, we discuss different strategies for preparing
polymer nanocomposite membranes, their performance, and critical issues to be addressed. In addition, we
discussed the scalability and the economic feasibility of membrane-based systems for wastewater treatment
Distribution of Element oxides or minerals depending on the high to low density/gravity of some selected coal
No full textThe element oxides or minerals that are found in coal can be classified into koalinite, quartz, siderite, hematite, etc. The effects of these element oxides or mineral matter during gravity fractionation were studied. The float and sink methods and sieving were employed to partition the ground coal. The principal techniques include LAT using quantitative evaluation of X-ray diffraction; HAT for conventional geochemical analysis; and knowing the morphological structures and elemental compositions with the help of Fe-SEM and EDS. Kaolinite was recorded at (31.38–33.23%) high at heavier gravity fractions and at low concentrations (7.38–14.08%) at lower gravity fractions. Quartz ranged from 24.16 to 32.36% in heavier gravity fractions and from 5.79 to 12.33% in lower gravity fractions. Sanidine (AlSi3O8) was reported at 21.4% in the heavy fraction. The behaviour of four elements, Ca, Al, Fe, and K, was reported at around 1.1-2.0 mg/kg in heavy gravity fraction after removing these at around 0.01 to 0.41 mg/kg. It was probably derived from the interaction of organically-associated coals during the low-temperature ashing process, but in lower fractions, it was recorded at a trace level. There are almost 3 to 4 times the separation noted for most of the obstacle elemental oxide
Required strength design of cemented backfill for underground metalliferous mine
No full textDetermination of the minimum required strength of backfill is the key design aspect for underground mining with backfill. In this study, a 3D simulation model was developed for predicting the required strength of backfill and displacement contours, yield state, and strength/stress ratios were considered to evaluate the stability and failure mechanism of backfill. The backfill design strength, assessed from numerical modelling, was compared with the previously developed analytical solutions. Further, the developed 3D simulation model was successfully used for backfill strength estimation of a few underground stopes in Eastern and Western India
Internal and cross sectional benchmarking of electrical energy use in opencast coal mine
No full textElectrical energy consumption in the opencast coal mine is very high. Electric shovels, pumps and coal handling plants consume 75% of the total electricity consumption of an opencast coal mine. In this paper, a modelling framework has been developed for electrical energy use benchmarking (internal as well as cross-sectional) of the mine. To develop a mine specific model for benchmarking electrical energy use statistical approach (linear regression method) has been applied. Specific power consumption (SPC) is used as a benchmarking index to assess the operating energy performance of a specific mine and multiple coal mines of India based on the field studies. Seasonal analysis of the electrical energy usage has also been analysed. Our results show the benchmark SPC as 0.50 kWh/t and the energy-saving potential as 10.7% for a single mine and the benchmark SPC of multiple coal mines as 0.52 kWh/t. The result concludes that SPC widely depends on its capacity and mining method and the developed model are useful for benchmarking and targeting for efficient electrical energy use in opencast mine
Study on Critical Factors Influencing Crown Pillar’s Stability through Numerical Simulation
No full textMining is a defined process through which valuable minerals are extracted from the earth's crust either using the surface or underground operations. Surface/Open pit mining is the most common approach, used to extract ore from shallow depths. Underground mining, on the other hand, is used to extract deposits at greater depths and when open pit mining is no longer economically feasible or due to lateral extent limitations, the majority of open cast mines must transition from open pit to underground at a certain depth. This transition necessitates the existence of a barrier pillar between the surface and underground mines in order to keep one working area separate from the underground workings and is referred to as a Crown pillar. This barrier pillar is critical throughout the mining operation, and its stability analysis is vital to protect both surface mine slopes and underground my infrastructure. Because of variations in geo-mining conditions, the crown pillar behaves differently than the surface crown, which is commonly leftover barrier at the surface in direct underground mining operations. Stresses reorient around the crown pillar during the underground mining operations and leads to the occurrence of displacements, which can be evaluated using numerical simulation techniques. This paper focuses on the behaviour of crown pillar and its key factor’s influence on its stability by interpreting the stresses and displacements using FLAC3D software
Negative δ13Ccarb excursions within early part of the Lomagundi event recorded in the Paleoproterozoic sedimentary carbonates, Aravalli Supergroup, Rajasthan India: Chemostratigraphy and basin evolution
No full textHigh resolution stable isotopic (C and O) and geochemical studies of Paleoproterozoic carbonates were carried
out in the Umra sub-basin of the Aravalli Supergroup, Rajasthan, India. All the sections, Umra-Dedkiya (UM),
Umra-Jampa (BD), and Matoon (MU and GU), have yielded characteristic Lomagundi type positive values, with
δ13Ccarb > 4 ‰ VPDB (maximum up to 6.86 ‰). Samples of two sections (UM and BD) have also yielded several
distinct negative δ13Ccarb values (up to − 6.14 ‰ VPDB). Geochemical validation of trace element and REE data
indicate both these types of excursions to be of pristine character, with no signature of organic-remineralisation
or hypersaline depositional condition. Mineralogical assemblages lack hypersalinity indicator minerals, such as
Na-tourmaline, Na-Albite or scapolite, in the positive δ13C bearing carbonate samples. This supports the infer-
ence regarding the observed positive δ13C excursions mimicking the global Paleoproterozoic Lomagundi event.
Chemostratigraphic correlation within the basin and with one of the global strato-type Paleoproterozoic car-
bonate unit from Paso Severino Formation, Uruguay, indicate interruptions in the initial part of the Lomagundi
episode marked by several negative δ13C excursion events before achieving a stable positive δ13C character. This
phenomenon is also evident from variation in paleo productivity proxies, such as TOC, TN, Ba and P values,
consistent with δ13C fluctuations. Mathematical model calculations have corroborated such a conclusion. All
these observations motivated us to present a modified version of the global Paleoproterozoic δ13Ccarb curve and a
six stage basin evolution model to explain the evolution of δ13C vis-`a-vis variation in atmospheric oxygen