Geochemical and petrological studies of high sulfur coal and overburden from Makum coalfield (Northeast India) towards understanding and mitigation of acid mine drainage

Opencast coal mining produces trash of soil and rock containing various minerals,that are usually dumped nearby the abandoned sites which causes severe environmental concern including the production of acid mine drainage(AMD)through oxidation pyrite minerals.The current study entailed assessing the potential production of AMD from an opencast coal mining region in Northeast part of India.In order to have a comprehensive overview of the AMD problem in Makum coalfield,the physico-chemical,geochemical,and petrological characteristics of the coal and overburden(OB)samples collected from the Makum coalfield(Northeast India)were thoroughly investigated.The maceral compositions reveal that coal features all three groups of macerals(liptinite,vitrinite,and inertinite),with a high concentration of liptinite indicating the coal of perhydrous,thereby rendering it more reactive.Pyrite(FeS_(2))oxidation kinetics were studied by conducting the aqueous leaching experiments of coal and(OB)samples to interpret the chemical weathering under controlled laboratory conditions of various temperature and time periods,and to replicate the actual mine site leaching.Inductively coupled plasma-optical emission spectroscopy(ICP-OES)was operated to detect the disposal of some precarious elements from coal and OB samples to the leachates during our controlled leaching experiment.The Rare earth element(REE)enrichment in the samples shows the anthropogenic incorporation of the REE in the coal and OB.These experiments reveal the change in conductivity,acid producing tendency,total dissolved solid(TDS),total Iron(Fe)and dissolved Sulfate(SO_(4)^(2−))ions on progress of the leaching experiments.Moreover,the discharge of FeS_(2) via atmospheric oxidation in laboratory condition undergoes a significant growth with the rise of temperature of the reaction systems in the environment and follows pseudo first order kinetics.A bio-remediative strategies is also reported in this paper to mitigate AMD water by employing size-segregated powdered limestone and water hyacinth plant in an indigenously developed site-specific prototype station.Apart from neutralisation of AMD water,this eco-friendly AMD remediation strategy demonstrates a reduction in PHEs concentrations in the treated AMD water.

快速热处理化学气相沉积法制备用于电子产品热管理的轻质柔性石墨烯

下一代电子产品的飞速发展对热管理提出了更高的要求。初始石墨烯的导热性是铜的13倍。本文通过快速热处理化学气相沉积(RTP-CVD)法制备了具有大sp^(2)结构域的单层、双层和多层石墨烯(SLG、BLG、FLG),进一步通过低浓度H_(2)还原制备了高导热石墨烯。在1000℃下生长25 min制备出SLG,利用拉曼光谱和透射电子显微镜(TEM)研究了石墨烯的品质。为了验证RTP-CVD法生成的石墨烯的散热能力,将其作为2TB固态硬盘的散热器,通过红外热成像仪进行了研究。结果证明,RTP-CVD生长的石墨烯用于消费电子产品的热管理测试时性能表现优异。SLG显示温度(最高)比商用铜散热器低5℃,SLG的散热能力比商用铜散热器快200倍左右。综上,利用RTP-CVD法制备的轻质的柔性石墨烯可以成为下一代5G设备和消费电子产品热管理的更好选择。

Legumes from the Paleocene sediments of India and their ecological significance

During the early Paleogene,greenhouse gases created warm global climates.These warm climates redistributed the habitat of marine and terrestrial biota globally.Understanding the ecology of biotas under extremely warm climates is important to decipher their behavior in future climate warming.Here we report two new legume fossils(Leguminocarpum meghalayensis Bhatia,Srivastava et Mehrotra sp.nov.,and Parvileguminophyllum damalgiriensis Bhatia,Srivastava et Mehrotra sp.nov.) from the late Paleocene sediments of Tura Formation of Meghalaya,northeast India.Globally,the Paleocene legume fossil records indicate that legumes most likely immigrated to India from Africa via the Ladakh-Kohistan Arc during the early Paleogene.Moreover,previously reconstructed climate data from the Tura Formation indicate that legumes were well adapted to a warm seasonal climate with monsoon rains.

Human Factors While Using Head-Up-Display in Low Visibility Flying Conditions

Flying an aircraft in low visibility is still a challenging task for the pilot.It requires precise and accurate situational awareness(SA)in real-time.A Head-up Display(HUD)is used to project collimated internal and externalflight information on a transparent screen in the pilot’s forwardfield of view,which eliminates the change of eye position between Head-Down-Display(HDD)instru-ments and outer view through the windshield.Implementation of HUD increases the SA and reduces the workload for the pilot.But to provide a betterflying capability for the pilot,projecting extensive information on HUD causes human factor issues that reduce pilot performance and lead to accidents in low visibility conditions.The literature shows that human error is the leading cause of more than 70%of aviation accidents.In this study,the ability of the pilot able to read background and symbology information of HUD at a different level of back-ground seen complexity,such as symbology brightness,transition time,amount of Symbology,size etc.,in low visibility conditions is discussed.The result shows that increased complexity on the HUD causes more detection errors.

Experimental studies on liquefaction and reliquefaction potential of saturated ground subjected to repeated incremental acceleration loading with varying shaking duration

Past research has focused on the factors that influence liquefaction under normal shaking conditions.However,studies on parameters that influence the reliquefaction potential of saturated deposits during repeated shaking events are limited.In this study,an attempt has been made to examine the influence of acceleration amplitude and shaking duration on liquefaction and reliquefaction potential under repeated shaking conditions is conducted.1-g uni-axial shaking table experiments were performed on saturated ground prepared with 40%and 60%relative density.The prepared ground was subjected to alternate longer and shorter shaking durations(40 and 20 s)of repeated incremental 0.1 g,0.2 g,0.3 g and 0.4 g acceleration loading,respectively.The variation in density,excess pore water pressure(EPWP),cyclic resistance ratio(CRR)and surface settlement were estimated.The results showed that due to repeated incremental shaking events,reliquefaction was observed on the prepared ground.During longer shaking duration,the post-liquefied soil showed density improvement with improved soil resistance.However,the application of shorter duration loading followed by longer shaking reduced the beneficial effect of density improvement by disturbing the densified ground.Due to this,the ground was found to be more susceptible to reliquefaction in the subsequent incremental longer shaking event.

Mesoporous titanium-aluminosilicate as an efficient catalyst for selective oxidation of cyclohexene at mild reaction conditions

Mesoporous titanium containing alumino-silicate materials with various titanium/silicon(Ti/Si) ratio(AlSi-Ti(n);n = Ti/Si mole ratio) have been successfully synthesized by a novel single-step sodium(Na)-free method, for the first time. The obtained characterization results of the prepared materials reveal that in-situ addition of Ti into AlSi shows ordered mesoporous structure along with uniformly dispersed Ti species in +4 and +3 oxidation states suitable for selective oxidation of allylic C—H bond. The prepared mesoporouse Ti-AlSi(n) samples exhibited excellent activity in the oxidation of cyclohexene with 100%conversion and 100% selectivity to ketone-alcohol(KA) oil(cyclohex-2-en-1-ol and 2-cyclohexen-1-one) at low temperature and reaction time(35℃ and 30 min reaction time). This study suggests that AlSi-Ti(0.05) material can be a promising catalyst for the selective oxidation of cyclohexene under mild reaction conditions.

Geochemical and mineralogical evaluations of coal,shale,and mine waste overburden from Makum coalfield of the Northeast India

The Cenozoic-age Makum coal from northeastern India offers numerous research opportunities because of its diverse geochemical and geological characteristics.Due to its high sulfur content,the coal has been found to be less useful for industrial purposes.It can,however,serve as a hub for ongoing research on coal-based derivative products.The aim of this research work is to investigate the mineralogical and geochemical compositions of the coal,mine overburden(MOB)and shale samples taken from the Makum coal field and also on establishing a mutual relationship between them.To characterize the geochemical controlling factors of the Makum coal field,the study employs coal petrography,FTIR,mineralogical,and geochemical analysis.According to X-ray diffraction analysis,the major minerals like quartz,kaolinite,haematite,illite,pyrite,and calcite are present in coal and MOB.Pyrite is observed by SEM-EDS analysis as cubic-shaped particles that are smaller than a fewμm in size.The presence of sulfide minerals represents a phase of pyrite mineralization.The petrography study was used to better understand the environment that existed during the formation of the plant material,which aids us in determining the quantity of detrital mineral sediment contained in the coal.According to the ICP-MS analysis,the samples indicate significant levels of rare earth elements including yttrium.The present study reveals higher concentrations of poten-tial hazardous elements in the coal samples,with V,Cr,Ni,Cu,and Zn content in coal being considerably enriched compared to world-average concentrations.The correlation analysis reveals that the potential hazardous elements like Co,Ni,As,and Cu are associated with pyrite as they have strong affinity towards pyrite.Thus,numerous minerals and rare earth elements(REEs)exist,opening up a fresh avenue for more research in the area.This study also assists researchers in understanding the significance of Makum coal and provides numerous ideas for coal characterization.

A strategic way of high-performance energy storage device development with environmentally viable “Water-in-salt” electrolytes

Development of cost-effective and environmental friendly energy storage devices(ESDs) has attracted widespread attention in recent scenario of energy research.Recently,the environmentally viable "water-in-salt"(WiS) electrolytes has received significant interest for the development of advanced high performance ESDs.The WiS electrolyte exhibits wide electrochemical stability window(ESW),highsafety,non-flammability and superior electrochemical performance compared to the conventional "salt-in-water" electrolytes.This review aims to provide a comprehensive discussion on WiS electrolyte based on theoretical,electrochemical and physicochemical characteristics.A strategic way for the usage of WiS electrolyte in rechargeable metal-ion batteries and supercapacitors with potentially improved electrochemical performance has been reviewed systematically.This review also discussed the unique advantages of WiS electrolytes as well as the future scope and challenges.

Designing of future ornamental crops: a biotechnological driven perspective

With a basis in human appreciation of beauty and aesthetic values,the new era of ornamental crops is based on implementing innovative technologies and transforming symbols into tangible assets.Recent advances in plant biotechnology have attracted considerable scientific and industrial interest,particularly in terms ofmodifying desired plant traits and developing future ornamental crops.By utilizing omics approaches,genomic data,genetic engineering,and gene editing tools,scientists have successively explored the underlying molecular mechanism and potential gene(s)behind trait regulation such as floral induction,plant architecture,stress resistance,plasticity,adaptation,and phytoremediation in ornamental crop species.These signs of progress lay a theoretical and practical foundation for designing and enhancing the efficiency of ornamental plants for a wide range of applications.In this review,we briefly summarized the existing literature and advances in biotechnological approaches for the improvement of vital traits in ornamental plants.The future ornamental plants,such as light-emitting plants,biotic/abiotic stress detectors,and pollution abatement,and the introduction of new ornamental varieties via domestication of wild species are also discussed.

Analyzing the Prebiotic Potential of Glucosamine for Targeting the Gut Microbiome Health

Recognizing the composition and modulation of the microbiome, a viable therapeutic tool for multi-targeted therapy is a new strategy that has recently been explored. Glucosamine (GS) is being studied for its prebiotic potential in addition to being the most abundant and naturally occurring amino monosaccharide. The current study focuses on glucosamine’s prebiotic potential by assessing the stability of various GS concentrations (1% - 5%) in the gastrointestinal tract (GIT) and its ability to be fermented by the gut microbiota. The results showed that GS stimulated the most growth in L. acidophilus even after a longer incubation time than B. bifidum and L. acidophilus growth was concentration-dependent, with maximum growth at 3% with a simultaneous decrease in pH (5.6 - 1.7). The decrease in GS concentration with time also represented the growth of bacterial species, demonstrating the species’ utilization of GS. Furthermore, at 3%, GS also represented the prebiotic index of 1.9. In addition, the concentration of GS in various simulated GIT fluids was estimated in both fast and fed conditions to examine GS stability at various levels in the gut. The results showed that GS remained unaffected and non-digestible in all of the simulated GIT fluids (salivary, gastric, intestinal, and colonic), but there was a slight decrease in GS concentration (2.8%) in the fasted state of gastric fluid due to low pH levels (1.6). As a result, the findings are conclusive and suggest that GS possesses prebiotic properties.

Rapid metabolic fingerprinting with the aid of chemometric models to identify authenticity of natural medicines: Turmeric, Ocimum, and Withania somnifera study

Herbal medicines are popular natural medicines that have been used for decades.The use of alternative medicines continues to expand rapidly across the world.The World Health Organization suggests that quality assessment of natural medicines is essential for any therapeutic or health care applications,as their therapeutic potential varies between different geographic origins,plant species,and varieties.Classification of herbal medicines based on a limited number of secondary metabolites is not an ideal approach.Their quality should be considered based on a complete metabolic profile,as their pharmacological activity is not due to a few specific secondary metabolites but rather a larger group of bioactive compounds.A holistic and integrative approach using rapid and nondestructive analytical strategies for the screening of herbal medicines is required for robust characterization.In this study,a rapid and effective quality assessment system for geographical traceability,species,and variety-specific authenticity of the widely used natural medicines turmeric,Ocimum,and Withania somnifera was investigated using Fourier transform near-infrared(FT-NIR)spectroscopy-based metabolic fingerprinting.Four different geographical origins of turmeric,five different Ocimum species,and three different varieties of roots and leaves of Withania somnifera were studied with the aid of machine learning approaches.Extremely good discrimination(R^(2)>0.98,Q^(2)>0.97,and accuracy=1.0)with sensitivity and specificity of 100%was achieved using this metabolic fingerprinting strategy.Our study demonstrated that FT-NIR-based rapid metabolic fingerprinting can be used as a robust analytical method to authenticate several important medicinal herbs.

Identification of EST–SSRs and molecular diversity analysis in Mentha piperita

EST sequences of Mentha piperita available in the public domain(NCBI) were exploited to develop SSR markers. A total of 1316 ESTs were assembled into 155 contigs and 653 singletons and of these, 110 sequences were found to contain 130 SSRs, with a frequency of1 SSR/3.4 kb. Dinucleotide repeat SSRs were most frequent(72.3%) with the AG/CT(43.8%)repeat motif followed by AT/AT(16.2%). Primers were successfully designed for 68SSR-containing sequences(62.0%). The 68 primers amplified 13 accessions of M. piperita and 54 produced clear amplicons of the expected size. Of these 54, 33(61%) were found to be polymorphic among M. piperita accessions, showing from 2 to 4 alleles with an average of2.33 alleles/SSR, and the polymorphic information content(PIC) value varied between 0.13 and 0.51(average 0.25). All the amplified SSRs showed transferability among four different species of Mentha, with a highest in Mentha arvensis(87.0%) and minimum in Mentha citrata(37.0%). The newly developed SSRs markers were found to be useful for diversity analysis, as they successfully differentiated among species and accessions of Mentha.

Transition metal-based single-atom catalysts(TM-SACs);rising materials for electrochemical CO_(2) reduction

The continuous increase of global atmospheric CO_(2) concentrations brutally damages our environment. A series of methods have been developed to convert CO_(2) to valuable fuels and value-added chemicals to maintain the equilibrium of carbon cycles. The electrochemical CO_(2) reduction reaction(CO_(2)RR) is one of the promising methods to produce fuels and chemicals, and it could offer sustainable paths to decrease carbon intensity and support renewable energy. Thus, significant research efforts and highly efficient catalysts are essential for converting CO_(2) into other valuable chemicals and fuels. Transition metal-based single atoms catalysts(TM-SACs) have recently received much attention and offer outstanding electrochemical applications with high activity and selectivity opportunities. By taking advantage of both heterogeneous and homogeneous catalysts, TM-SACs are the new rising star for electrochemical conversion of CO_(2) to the value-added product with high selectivity. In recent years, enormous research effort has been made to synthesize different TM-SACs with different M–Nxsites and study the electrochemical conversion of CO_(2) to CO. This review has discussed the development and characterization of different TMSACs with various catalytic sites, fundamental understanding of the electrochemical process in CO_(2) RR,intrinsic catalytic activity, and molecular strategics of SACs responsible for CO_(2)RR. Furthermore, we extensively review previous studies on 1 st-row transition metals TM-SACs(Ni, Co, Fe, Cu, Zn, Sn) and dual-atom catalysts(DACs) utilized for electrochemical CO_(2) conversions and highlight the opportunities and challenges.

Identification and characterization of phenolics and terpenoids from ethanolic extracts of Phyllanthus species by HPLC-ESI-QTOF-MS/MS

Phyllanthus species plants are a rich source of phenolics and widely used due to their medicinal properties. A liquid chromatography–tandem mass spectrometry(LC–MS/MS) method was developed using high-pressure liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry(HPLC-ESI-QTOFMS/MS) for the identification and characterization of quercetin, kaempferol, ellagic acid and their derivatives in ethanolic extracts of Phyllanthus species. The chromatographic separation was carried out on Thermo Betasil C_8 column(250 mm×4.5 mm, 5 μm) using 0.1% formic acid in water and 0.1% formic acid in methanol as the mobile phase. The identification of diagnostic fragment ions and optimization of collision energies were carried out using 21 reference standards. Totally 51 compounds were identified which include 21 compounds identified and characterized unambiguously by comparison with their authentic standards and the remaining 30 were tentatively identified and characterized in ethanolic extracts of P. emblica, P. fraternus, P. amarus and P.niruri.

Review of preventive and constructive measures for coal mine explosions:An Indian perspective

Firedamp and coal dust explosion constitute a lion’s share in mine accidents in a global mining scenario.This paper reports a list of mine explosion disasters since last two decades,a critical review of the different prevention and constructive measures,and its recent development to avoid firedamp and coal dust explosion.Preventive legislation in core coal-producing countries,viz.China,USA,Australia,South Africa,and India related to firedamp and coal dust explosion are critically analysed.Accidents occurred due to explosion after Nationalisation of Coal Mines(1973)in India are listed.Prevention and constructive measures adopted in India are critically analysed with respect to the global mining scenario.Measures like methane credit concept,classification of mines/seams with respect to explosion risk zone,deflagration index;installation of automatic fire warning devices,canopy air curtain technology,explosion-prevention measures,such as fire-retardant materials,inhibitors,extinguishing agent,dust suppressor,and active explosion barrier are discussed in detail to avoid explosion and thereby adhering to zero accident policy due to coal mine explosion.

Next-Generation Intelligent MXene-Based Electrochemical Aptasensors for Point-of-Care Cancer Diagnostics

Delayed diagnosis of cancer using conventional diagnostic modalities needs to be addressed to reduce the mortality rate of cancer.Recently,2 D nanomaterial-enabled advanced biosensors have shown potential towards the early diagnosis of cancer.The high surface area,surface functional groups availability,and excellent electrical conductivity of MXene make it the 2 D material of choice for the fabrication of advanced electrochemical biosensors for disease diagnostics.MXene-enabled electrochemical aptasensors have shown great promise for the detection of cancer biomarkers with a femtomolar limit of detection.Additionally,the stability,ease of synthesis,good reproducibility,and high specificity offered by MXene-enabled aptasensors hold promise to be the mainstream diagnostic approach.In this review,the design and fabrication of MXene-based electrochemical aptasensors for the detection of cancer biomarkers have been discussed.Besides,various synthetic processes and useful properties of MXenes which can be tuned and optimized easily and efficiently to fabricate sensitive biosensors have been elucidated.Further,futuristic sensing applications along with challenges will be deliberated herein.

Structural characterization of monoterpene indole alkaloids in ethanolic extracts of Rauwolfia species by liquid chromatography with quadrupole time-of-flight mass spectrometry

Rauwolfia species(Apocynaceae) are medicinal plants well known worldwide due to its potent bioactive monoterpene indole alkaloids(MIAs) such as reserpine,ajmalicine,ajmaline,serpentine and yohimbine.Reserpine,ajmalicine and ajmaline are powerful antihypertensive,tranquilizing agents used in hypertension.Yohimbine is an aphrodisiac used in dietary supplements.As there is no report on the comparative and comprehensive phytochemical investigation of the roots of Rauwolfia species,we have developed an efficient and reliable liquid chromatography-tandem mass spectrometry(LC–MS/MS) method for ethanolic root extract of Rauwolfia species to elucidate the fragmentation pathways for dereplication of bioactive MIAs using highperformance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry(HPLC–ESI–QTOF–MS/MS) in positive ion mode.We identified and established diagnostic fragment ions and fragmentation pathways using reserpine,ajmalicine,ajmaline,serpentine and yohimbine.The MS/MS spectra of reserpine,ajmalicine,and ajmaline showed C-ring-cleavage whereas E-ring cleavage was observed in serpentine via Retro Diels Alder(RDA).A total of 47 bioactive MIAs were identified and characterized on the basis of their molecular formula,exact mass measurements and MS/MS analysis.Reserpine,ajmalicine,ajmaline,serpentine and yohimbine were unambiguously identified by comparison with their authentic standards and other 42 MIAs were tentatively identified and characterized from the roots of Rauwolfia hookeri,Rauwolfia micrantha,Rauwolfia serpentina,Rauwolfia verticillata,Rauwolfia tetraphylla and Rauwolfia vomitoria.Application of LC–MS followed by principal component analysis(PCA) has been successfully used to discriminate among six Rauwolfia species.

An account of the strategies to enhance the water splitting efficiency of noble-metal-free electrocatalysts

The electrolysis of water for hydrogen generation has shown immense promise as an energy conversion technology for the green energy economy.Two concurrently occurring electrochemical reactions in water electrolysis(hydrogen and oxygen evolution reactions)are sluggish in nature and therefore the employment of electrocatalysts is highly essential.Noble-metal-based electrocatalysts(Pt,Ru O_(2),Ir O_(2),etc.)have shown superior activity towards these reactions.However,their lower natural abundance and inferior stability make the cost to performance ratio of water electrolysis too high.Thus,huge amount of research efforts are being carried out to develop electrocatalysts consisting of earth abundant elements(transition metals,carbon etc.)as the replacement of these noble-metal-based materials.Transition metal compounds,carbonaceous and hybrid materials have shown promise as efficient electrocatalysts but there is still huge gap between the activities of these materials and the noble-metal-based electrocatalysts.Several strategies like morphology modulation,elemental doping,defect engineering etc.are being deployed to enhance the activity of these noble-metal-free electrocatalysts.This review summarizes these strategies and thoroughly discusses the reason behind the changes in activity of the electrocatalysts owing to these modifications.Finally,the remaining research gaps and future prospects in this field are also discussed in detail.

TGA/DSC study to characterise and classify coal seams conforming to susceptibility towards spontaneous combustion

Thermogravimetric analysis/differential scanning calorimeter(TGA/DSC)technique along with basic coal characteristics study is carried out for eighty coal samples of Indian coalfields,to determine spontaneous combustion propensity behaviour of coal.TGA study of coal samples indicates that there is an increase in the mass of coal samples in the temperature range 150-350℃,which may be due to oxygen adsorption and absorption.The correlation and principal component analysis states that the component of proximate analysis(M_(ad),VM_(d),FR,and VR)have an acceptable correlation with the TGA experiments results i.e.,Tgsh and Tgign.Multiple fixed nonlinear regression analysis shows that thermogravimetry(TG)experiment results Tgign may be the best index to categorise/classify the coal as per their susceptibility towards spontaneous combustion.The authors proposed four groups of classification as per their propensity towards spontaneous combustion depending upon the moisture(M_(ad)),volatile matter(VM_(d)),and TG ignition temperature from differential thermogravimetric(DTG)curve(Tgign)using hierarchal clustering analysis.The coal samples of different seams from Indian coalfield may be classified into four different clusters,viz.very highly/extremely susceptible(Tgign<260℃),highly susceptible(260℃≤Tgign<290℃),moderately susceptible(290℃≤Tgign≤320℃),and poorly susceptible(Tgign>320℃).The field observations and TGA/DSC experiment results with the following statistical analysis substantiate a similar assessment.

Seismic passive earth resistance using modified pseudo-dynamic method

In earthquake prone areas, understanding of the seismic passive earth resistance is very important for the design of different geotechnical earth retaining structures. In this study, the limit equilibrium method is used for estimation of critical seismic passive earth resistance for an inclined wall supporting horizontal cohesionless backfill. A composite failure surface is considered in the present analysis. Seismic forces are computed assuming the backfill soil as a viscoelastic material overlying a rigid stratum and the rigid stratum is subjected to a harmonic shaking. The present method satisfies the boundary conditions. The amplification of acceleration depends on the properties of the backfill soil and on the characteristics of the input motion. The acceleration distribution along the depth of the backfill is found to be nonlinear in nature. The present study shows that the horizontal and vertical acceleration distribution in the backfill soil is not always in-phase for the critical value of the seismic passive earth pressure coefficient. The effect of different parameters on the seismic passive earth pressure is studied in detail. A comparison of the present method with other theories is also presented, which shows the merits of the present study.