SBA-15 is synthesized using triblock copolymer Pluronic P123 as the structure directing agent and different silica sources such as tetraethyl orthosilicate (TEOS), sodium metasilicate, coal fly ash (CFA) derived supernatant and a mix of sodium metasilicate, CFA-derived supernatant for comparative study towards Fischer-Tropsch synthesis (FTS). The active metal cobalt (15 wt. %) has been impregnated in each support via the wet impregnation technique. The catalysts and supports are characterized by N2 adsorption-desorption, Field Emission Scanning Electron Microscopy (FESEM), High-Resolution Transmission Electron Microscopy (HRTEM), X-ray Diffraction (XRD), X-ray Energy Dispersion Spectrophotometer (EDX), Fourier Transform Infrared (FTIR), and Temperature Programmed Reduction (TPR). The catalytic performance of synthesized catalysts for the FTS has been investigated in a fixed bed tubular reactor at T=220 °C, P=30 bar, and GHSV=500 h−1 using simulated syngas composition equivalent to coal-derived syngas using air blown fixed bed gasifier having H2/CO molar ratio of 2 : 1. The maximum CO conversion and middle distillate (C6−C20) selectivity is observed as 59.2 % and 84.6 % respectively for the catalyst support synthesized from mix of sodium metasilicate and CFA-derived supernatant.
Groundnut shells (GNS) are renewable and sustainable sources that can reinforce polypropylene for composites intended for interior building and other applications. However, the hydrophilicity, low thermal and noise insulation of GNS reinforced polypropylene (PP) necessitate the use of additives to improve properties. In this work, non-coking bituminous coal was used as an additive to improve the properties of GNS-PP composites. Up to 30% of coal particles were included and the changes in tensile, flexural properties and noise and thermal insulation were studied. Morphological analysis showed limited interaction of coal with GNS or PP and consequently, there was only marginal improvement in the mechanical properties. However, moisture sorption of the composites decreased by 25% and the limited oxygen index increased to 27 from 24 without any coal. The presence of coal increases sound absorption and the noise absorption coefficient showed high absorption at specific frequencies. Coal is an abundantly available natural material which is suitable to improve the performance of composites.
Performance of TBM is significantly influenced by the ground conditions and machine variables. To achieve an optimum rate of penetration (ROP) during TBM excavation, it is important to assess the interaction between rock mass properties and machine operational/performance variables. This paper presents a systematic analysis of TBM performance based on the data collected from the MetroLine-3 UGC-01 project in Mumbai, India, and proposes a few performance prediction models for the Deccan Traps. The current work attempted to bring out the combined effect of RQD × Js as a single predictor variable while suggesting a reliable RSA modeling technique which considers the simultaneous interaction of variables. The database consisted of engineering-geological and machine variables; the selected variables were analyzed using artificial neural networks (ANN) for identifying the significant variables. Subsequently, multivariate regression (MVRA) and response surface analysis (RSA) were utilized to develop a model for predicting TBM ROP. The first model developed using MVRA as a function of rock mass variables yielded a coefficient of determination (R2) of 0.80, whereas the second composite model developed as a function of geological and machine variables yielded an R2 of 0.85. The third model was developed utilizing RSA which resulted in 2FI (two-factor interaction) model with improved R2 of 0.88. Further, the best-performing RSA model accuracy is compared with the existing models and subsequently validated using new datasets and yielded an R2 of 0.79. The developed model equation indicates that UCS, RQD × Js, and thrust variables show significant influence on the TBM ROP.
This investigation addresses the minimum fluidization velocity (Umf) determination in a refractory insulated fluidized bed reactor (FBR) of 200 mm ID. Umf is determined with respect to different particle sizes and operating parameters like temperature and pressure up to 900 °C and 1 MPa respectively. This study has the main thrust into the establishment of Umf at elevated temperature and pressure during the thermochemical process, involving uniform mixing of gas-solid by fluidization phenomena at a pilot scale FBR. So, to understand the significance and impact of temperature along with pressure on Umf, a set of fluidization experiments have been demonstrated in FBR. Two waste materials are abundantly available, similar to Geldart’s group-B type bed materials, i.e. Calcined-clay and Coal-ash of an average size of 1.04 and 0.92 mm respectively, and apparent density of 883 and 850 kg/m³ respectively, have been selected as bed material. Experimental results revealed that Umf directly relates to particle size and inverse relationship with operating temperature and pressure. Results revealed that Umf decreases by 59.7% and 59.2% for both bed materials such as Calcined-clay and Coal-ash respectively as the temperature increases from 30 to 900°C at atmospheric pressure. Similarly, Umf also decreases by 63.3% and 66.0% for bed materials such as Calcined-clay and Coal-ash respectively as the pressure increases from atmospheric pressure to 1 MPa at room temperature. An empirical model has been developed for predicting Umf at elevated temperature and pressure during fluidization phenomena. The experimental Remf shows a good agreement with the predicted Remf by using the developed model proving its robustness.
In 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, 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.
Additives provide substantial improvement in the properties of composites. Although bio-based composites are preferred over synthetic polymer and metal-based composites, they do not have the requisite properties to meet specific needs. Hence, organic, inorganic and metallic additives are included to improve the properties of bio-based composites. Coal is a readily available resource with high thermal insulation, flame resistance and other properties. This work demonstrates the addition of 20–30% natural sub-bituminous coal as filler for coir-reinforced polypropylene (PP) composites and exhibits an increased tensile strength by 66% and flexural strength by 55% compared to the composites without any filler. Such composites are intended for insulation applications and as a replacement for gypsum-based false ceiling tiles. Various ratios of coal samples were included in the composites and their effect on mechanical, acoustic, thermal insulation, flame and water resistance have been determined. A substantial improvement in both flexural and tensile properties has been observed due to the addition of coal. However, a marginal improvement has been observed in both thermal conductivity (0.65 W/mK) and flame resistance values due to the presence of coal. Adding coal increases the intensity of noise absorption, particularly at a higher frequency, whereas water sorption of the composites tends to decrease with an increase in the coal content. The addition of coal improves and adds unique properties to composites, allowing coir–coal–PP composites to outperform commercially available gypsum-based insulation panels.
Methanol synthesis from syngas is an effective method for producing fuel additives, oxygenated fuels, and other chemicals. Several promoted catalytic systems have been tested for the synthesis of methanol. Catalysts based on noble metals are extremely active in generating methanol from syngas. However, sintering, poisoning, and related expenses accounted for the switch to Cu‐based catalysts. The promotion of Cu‐based catalysts, even with small doses of an effective promoter, resulted in a considerable change in product selectivity. A suitable promoter is required for Cu‐based catalysts used in the synthesis of methanol because it significantly impacts the electronic, geometric, or acid/base surface properties, which in turn affect the catalyst's activity and selectivity. It also significantly impacts the interactions between the catalyst's active ingredients. However, the interactions between the active component and the promoter can be adjusted or influenced by appropriate support. The present paper primarily focuses on several promoters in the copper‐based catalyst for synthesizing methanol from syngas. Briefly deliberated on the need for Cu‐based catalysts for methanol synthesis, their reaction & mechanism, cause for promoter's addition concerning their role & influence, the importance of CO2 addition in feed synthesis gas & their impact on the catalyst. This paper mainly highlights the selectivity and activity of various promoted Cu‐based catalysts, although different parameters for the cause of promotion and inhibitions in the catalyst. The effect of reaction conditions, including pressure, temperature, gas hourly space velocity (GHSV), and syngas composition, is briefly reported. Herein, this paper also comprehensively compares the effects of adding various promoters in small amounts to Cu‐based catalysts. This review intends to be illustrative rather than exhaustive. This article is protected by copyright. All rights reserved.
The pressure drop across the distributor signifies the total pressure drop and ensures desired fluidization in the fluidized bed. This study estimates the pressure drop requirements for 1.2 and 2.05 mm particles utilizing two distinct perforated type conical distributors with 154 and 302 orifices, respectively. The investigation was carried out in a cold flow condition. The pressure drop across the distributor was introduced in this investigation by filling bed material in the conical portion of the distributor. To estimate the bed pressure, a combined pressure drop of the conical distributor with and without bed material was approached. Explicitly, pressure drop requirements for the minimum fluidization and bubbling regimes have been focused on and presented in this work. In view of bed pressure, an attempt has been made to establish a relationship for pressure requirements across distributors. The integration and estimation of pressure drop across distributor with bed material in conical portion could be very beneficial in view of the fluidized bed. As the bed height increased, the pressure increased, but the pressure drop ratio decreased for the selected particles. The distributor features a higher number of orifices that demonstrate lower pressure requirements during fluidization and bubbling regimes. This study emphasizes the desired pressure requirements for the fluidized bed.
The longleaf pine ( Pinus palustris Mill.) and related ecosystem is an icon of the southeastern United States (US). Once covering an estimated 37 million ha from Texas to Florida to Virginia, the near-extirpation of, and subsequent restoration efforts for, the species has been well-documented over the past ca. 100 years. Although longleaf pine is one of the longest-lived tree species in the southeastern US—with documented ages of over 400 years—its use has not been reviewed in the field of dendrochronology. In this paper, we review the utility of longleaf pine tree-ring data within the applications of four primary, topical research areas: climatology and paleoclimate reconstruction, fire history, ecology, and archeology/cultural studies. Further, we highlight knowledge gaps in these topical areas, for which we introduce the Longleaf Tree-Ring Network (LTRN). The overarching purpose of the LTRN is to coalesce partners and data to expand the scientific use of longleaf pine tree-ring data across the southeastern US. As a first example of LTRN analytics, we show that the development of seasonwood chronologies (earlywood width, latewood width, and total width) enhances the utility of longleaf pine tree-ring data, indicating the value of these seasonwood metrics for future studies. We find that at 21 sites distributed across the species’ range, latewood width chronologies outperform both their earlywood and total width counterparts in mean correlation coefficient (RBAR = 0.55, 0.46, 0.52, respectively). Strategic plans for increasing the utility of longleaf pine dendrochronology in the southeastern US include  saving remnant material ( e.g., stumps, logs, and building construction timbers) from decay, extraction, and fire consumption to help extend tree-ring records, and  developing new chronologies in LTRN spatial gaps to facilitate broad-scale analyses of longleaf pine ecosystems within the context of the topical groups presented.
Belgaon underground coal mine is located in Warora tehsil of Chandrapur district, Maharashtra, India. ‘Mayo seam’ at Belgaon mine has a total thickness of 11 m but only the bottom section is found to be mineable, which has seam thickness varying from 3.2 to 3.7 m. This coal seam is dipping at 1 in 6.25 to 1 in 20 and is being developed along the floor by leaving a coal layer of 0.5–0.6 m against the shale roof. Panel D2-1 of the seam is developed at a depth of approximately 230 m by Bord and Pillar method with pillars of 40 m × 40 m in size. This D2-1 Panel has been planned for depillaring with caving to extract the coal and accordingly support design work as well as hydro-geological study, which has been carried out both for safety and also for statuary compliance. This research paper focuses on the site-specific hydrogeological study performed for water assessment in the Moturs/Barakar coal formations including related water management. The study is based on the encountered geological conditions, local aquifer parameters and other site-specific field observations. Both primary data and secondary data have been used for analysis and discussion in this study. The scientific evaluation carried out concluded that extraction of coal from the Depillaring panel D2-1 is safe and the creation of goaf, as a result of the depillaring operation, will cause an insignificant impact on the water-charged Kamptee series as a whole. Encountered geological features of the underground working areas will play an important role in the magnitude of water quantity.
A combination of high-resolution imaging, low-pressure gas adsorption, and small-angle X-ray and neutron scattering quantifies changes in the pore characteristics of pulverized shale samples under oxic and anoxic environments up to 300 ℃. Clay-rich early-mature shales have a fair potential to generate hydrocarbons, the total organic carbon content of which lies within a range of 2.9 % to 7.4 %. High-resolution imaging indicates restructuring and coalescence of Type III kerogen-hosted pores due to oxic heating, which causes up to 580 % and 300 % increase in the surface area and pore volume of mesopores respectively. Similarly, up to 300 % and 1200 % increase in micropore surface area and pore volume is observed post oxic heating. However, during anoxic heating, bitumen mobilizes, leads to pore-blockage, and reduces the surface area and pore volume up to 45 % and 12 % respectively without any significant mass loss up to 350 ◦C. Between 400 and 550 ◦C, considerable loss in mass occurred due to breaking of organic matter, facilitated by the presence of siderite that caused up to 30 % loss in mass. The test conditions display starkly opposite effects in pores that have a width of < 100 nm when compared to the larger macropore domain, which has a pore width in the range of 100 to 700 nm as inferred from their small-angle X-ray (SAXS) and neutron (SANS) scattering behaviour, respectively. Despite the formation of new mesopores or the creation of new networks of pores with rougher surfaces, the fractal behavior of accessible mesopores in combusted shales minimally increase mesopore surface roughness. The pyrolyzed shales exhibit decreased mesopore surface roughness at higher temperatures, which indicates smoothening of pores due to pore blocking. Increase in pore volume and surface area due to oxic-heat treatment enhances the feasibility of long-term CO2 storage in shales.
Long-Hole Raising (LHR) is the prime excavation technique used for driving the vertical and steeply inclined raise structures in underground mining and civil construction projects. However, progress rate of raising is an important factor as it has enormous impact on cost and productivity. Therefore, to enhance the development rate of long raises under safe working conditions, several experimental LHR blasts in a single-shot have been conducted in the four underground metalliferous mines. This paper aimed to investigate the influence of void ratio (i.e. empty space) and delay time on the advancement of raises, considering fair and good quality of rock mass. In order to accomplish long raises, various parallel long-hole cut designs were executed in the first cut-section by varying void ratios ranging from 7.00 % to 36.50 %. Meanwhile, up to 25 m long raises were advanced effectively using one blast. As a result, it was found that amount of void ratio, and delay intervals between two adjacent blast-holes need to be increased adequately for longer length of raises (i.e. for higher degree of confinement factor). Subsequently, required void ratios and delay timing for the specific blast-holes length were assessed to succeed LHR blast in a single-shot. Regression analyses were carried out to establish the best-fitted model using residuals plot assumptions. Eventually, two empirical equations were derived between void ratio and blast-hole length, allowing for the fair and good quality of rock mass. Moreover, delay interval between adjacent blast-holes should be at least 22 times the blast-hole length for effective construction of long raises.
Global urbanization and industrialization are energy-intensive processes. Among different energy resources, fossil fuels meet more than 80 % of the energy demand. The factors such as the depletion of fossil fuel reserves, the unstable price of fossil fuels, and the emission of greenhouse gases (GHGs) due to the burning of fuels draw researchers’ attention towards the development of renewable and sustainable fuels. In this context, biomass may fill the gap between energy demand and petroleum availability in the foreseeable future. Moreover, half of this bioenergy comes from conventional uses of biomass, primarily in cooking and heating, as well as within small-scale industries (such as charcoal kilns and brick kilns). The Biomass-to-Liquid (BTL) technology using Fischer-Tropsch synthesis (FTS) and the Methanol process offers advantages over the traditional use of biomass. The FT/Methanol process is a propitious route to produce carbon-neutral, ultra-clean fuels that generate regulated emissions, including NOx, SOx, and PM. In this article, we have reviewed the processes of biomass gasification, syngas cleaning and conditioning, FTS and methanol synthesis.
A variety of coal room and pillar mining methods have been efficiently practiced at depths of up to 500 m with least strata mechanics issues. However, for the first time, this method was trialled at depths of 850–900 m in CSM mine of Czech Republic. The rhomboid-shaped coal pillars with acute corners of 70°, surrounded with 5.2 m wide and 3.5–4.5 m high mine roadways, were used. Pillars were developed in a staggered manner with their size variation in the Panel II from 83 m × 25 m–24 m × 20 m (corner to corner) and Panel V from 35 m × 30 m–26 m × 16 m. Coal seam inclined at 12° was affected by the unusual slippery slickenside roof bands and sometimes in the floor levels with high vertical stress below strong and massive sandstone roof. In order to ensure safety, pillars in both the panels were continuously monitored using various geotechnical instruments measuring the induced stresses, side spalling and roof sagging. Both panels suffered high amounts of mining induced stress and pillar failure with side-spalling up to 5 m from all sides. Heavy fracturing of coal pillar sides was controlled by fully encapsulated steel bolts. Mining induced stress kept increasing with the progress of development of pillars and galleries. Instruments installed in the pillar failed to monitor actual induced stress due to fracturing of coal mass around it which created an apprehension of pillar failure up to its core due to high vertical mining induced stress. This risk was reduced by carrying out scientific studies including the three-dimensional numerical models calibrated with data from the instrumented pillar. An attempt has been made to study the behavior of coal pillars and their yielding characteristics at deeper cover based on field and simulation results.
Hydrogen, 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.
In this paper, we discuss the necessity of mapping of characterisation of unapproachable underground mine workings by electrical resistivity tomography (ERT). Initially, numerical forward modelling is conducted for considering the possibilities of water fill and air fill void in old workings using Wenner–Schlumberger (WS), dipole–dipole (DD) and inversion of joint of both arrays (WS+DD). Considerable accuracy of cavities dimension, depth and extensions could be recovered from data inversion of joint of both arrays (WS+DD). In field, 2D ERT survey was conducted along three parallel profiles using said configurations over Jharia coalfield, India. Inversion of joint of both arrays was introduced during data analysis for propensities of better demarcation of underground mine workings characterisations under complex geological formations. Furthers, pseudo-3D model was also done by merging 2D ERT parallel profile data for improved visualisation of 3D resistivity distributions of surveyed area. High resistivity contrast in 2D ERT model and 3D volumetric iso-resistivity model provided comfortable guidance in the investigation of possible continuity of barrier between caved panels of XVIA seam. Moderately low resistivity indicated anticipation of XVII seam working filled with water and also validated through the existing mine plan. Thus, interpretation of 3D data eventually helped in convincing outcomes.
The Bundelkhand region of Central India has been facing increasing severity of droughts, water-level depletion and deterioration in water quality. In this perspective, an attempt has been made for a qualitative evaluation of surface and groundwater resources belonging to the rural environment of this region to understand the contaminant’s source and probable human health risk due to the intake of the available water. The water samples collected from this region were analysed for pH, electrical conductivity (EC), total dissolved solids (TDS), turbidity, total hardness (TH), major anions (F⁻, Cl⁻, HCO3⁻, SO4²⁻, NO3⁻) and major cations (Ca²⁺, Mg²⁺, Na⁺, K⁺). The observations revealed a near-neutral to slightly alkaline nature of the studied water samples. The computed water quality index implies that around 82% water samples are of good to excellent category for drinking uses. Turbidity, TDS, TH and NO3⁻ were identified as the major parameters which violate the limits of drinking water. Geochemical investigations in association with multivariate statistical analysis identify carbonate weathering in coordination with the ion-exchange process as the major hydrogeochemical mechanism controlling the solute chemistry and concentrations of TH, TDS, HCO3⁻, F⁻, Ca²⁺, Mg²⁺ and Na⁺. On the contrary NO3⁻, Cl⁻, SO4²⁻ and K⁺ were strongly associated with anthropogenic activities. Water at most of the locations expresses positive saturation indices with respect to calcite and dolomite minerals, inferring the precipitation of these mineral phases. Sodium adsorption ratio (SAR) and percent sodium (%Na) values show a low alkali hazard and water can be used safely for irrigation purposes. However, high salinity in 39% of the water samples makes it unfit for application in agricultural fields. The non-carcinogenic hazard indices (HI) calculated by adding hazard quotient values of NO3⁻ and F⁻ for child, adult male and female population show that more than 64% of the water samples are deemed to be unfit for human consumption.
This paper presents the efforts made to design irregular-shaped-heightened-rib/snook based on factor of safety (FOS) during mechanised extraction of already developed coal pillars by continuous miner. In situ monitoring of performance of different sizes of rib/snook with variation in their area, effective-width, width-to-height ratio and height under varying geo-mining conditions are studied comprehensively at 39 panels of 7 different mines and found a number of influencing factors affecting its design as per the field studies. Based on this study, a number of conceptual models are developed to understand the need of rib/snook and its interaction with different nature of roof at varying depth of cover. Further, a parametric study is carried out on calibrated numerical models by varying the area and height of rib/snook with nature of roof, depth of cover and panel width for the estimation of strength and stress over it. Empirical formulations are developed for estimation of a competent area, effective width and width-to-height ratio in a given geo-mining condition corresponding to a limiting value of FOS of 0.30-0.35. Further, the results of developed empirical formulations are validated with the field studies.
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