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A comprehensive analysis of various structural parameters of Indian coals with the aid of advanced analytical tools
An exhaustive structural analysis was carried out on three Indian coals (ranging from sub-bituminous to high volatile bituminous coal) using a range of advanced characterization tools. Detailed investigations were carried out using UVVisible spectroscopy, X-ray diffraction, scanning electron microscopy coupled energy dispersive spectroscopy, Raman spectroscopy and Fourier transform infrared spectroscopy. The X-ray and Raman peaks were deconvoluted and analyzed in details. Coal crystallites possess turbostratic structure, whose crystallite diameter and height increase with rank. The H/C ratio plotted against aromaticity exhibited a decreasing trend, confirming the graphitization of coal upon leaching. It is also found that, with the increase of coal rank, the dependency of I20/I26 on La is saturated, due to the increase in average size of sp2 nanoclusters. In Raman spectra, the observed G peak (1585cm?1) and the D2 band arises from graphitic lattices. In IR spectrum, two distinct peaks at 2850 and 2920cm?1 are attributed to the symmetric and asymmetric CH2 stretching vibrations. The intense peak at ~1620cm?1, is either attributed to the aromatic ring stretching of C=C nucleus. 2016, The Author(s). -
Synthesis and characterization of porous, mixed phase, wrinkled, few layer graphene like nanocarbon from charcoal
A technique to synthesis wrinkled graphene like nano carbon (GNC) from charcoal is reported in the current study. The charcoal produced by thermal decomposition and is intercalated by Hummers method. It is separated by centrifugation and sonication to get few layer graphene sheets. The structural and chemical changes of the nanostructure is elucidated by Raman spectroscopy, TEM, SEM-EDS and XPS. Raman spectra revealed the existence of highly graphitized amorphous carbon, which is confirmed by the appearance of five peaks in the deconvoluted first order Raman spectra. The SEM analysis reveals the formation of large area graphene sheets with nano-porous structure in it. The TEM/SAED analysis exhibits the presence of short range few layer graphene. 2015 Pleiades Publishing, Ltd. -
Investigation of nanocrystalline structure in selected carbonaceous materials
The structural parameters of nine Indian coals were determined by X-ray diffraction (XRD) and Raman spectroscopy. The study revealed that the coals contain crystalline carbon of turbostratic structure with amorphous carbon. The stacking height (Lc) and interlayer spacing (d002) of the crystallite structure of the coals ranged from 1.986 to 2.373 nm and from 0.334 to 0.340 nm, respectively. The degree of graphitization was calculated to range from 42% to 99%, thereby confirming the ordering of the carbon layers with the increase in coal rank. An exponential correlation was observed among the aromaticity (fa), the lateral size (Lc), and the rank (I20/I26), suggesting that the coal crystallites are nanocrystalline in nature. A very strong correlation was observed between the structural parameters (fa, d002, Lc, the H/C ratio, and I20/I26), the volatile matter content, and the elemental carbon content, indicating the structures of coals are controlled by the degree of contact metamorphism. The Raman spectra exhibited two prominent bands: the graphitic band (G) and the first-order characteristic defect band (D). The deconvolution resulted in five peaks: G, D1, D2, D3, and D4. The intense D1 band, which appeared at ~1350 cm-1, corresponds to a lattice vibration mode with A1g symmetry. The D2 mode, which appeared at ~1610 cm-1, arises from the structural disorder as a shoulder on the G band. University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg 2014. -
Characterization of nano-crystalline carbon from camphor and diesel by x-ray diffraction technique
Hydrocarbons are by far the most widespread precursors among carbon sources employed in the production of carbon nanotubes and carbon nanosphers. In the present study, diesel and camphor have been used as precursors for nanomaterials. Carbonaceous soot produced from combustion of diesel in engine shows the presence of significant amount of carbon nanomaterials. The ? band at about 19.28 has been attributed to the presence of amorphous carbon and surface defects in carbon nanotubes. The ? band at about 25.81 corresponds to e2g mode of graphite which is related to vibration of sp2bonded carbon atoms and the presence of ordered carbon nanotubes in diesel soot. The SEM micrographs provide a clear indication that nanoparticle formed in diesel soot are clusters of carbon nanospheres. Energy dispersive spectrum analysis of diesel soot confirms that the soot particles to be composed of primarily carbon and oxygen along with hydrogen. The camphor soot shows ? and ? bands which reveals the presence of crystalline graphitic carbon. The SEM micrographs of camphor show the presence of carbon nanostructures. It is found nanomaterials formed in the diesel soot consists more of disordered carbon, whereas in camphor it is more of ordered graphite like carbon. -
Chemical leaching of an indian bituminous coal and characterization of the products by spectroscopic techniques
Fourier transform infrared (FTIR) spectra of high volatile bituminous coal as well as their insoluble organic matter, obtained by chemical leaching with HF, EDTA and acid mixture (HF + HCl and HF + HNO3) were recorded between 500 and 4000 cm-1. UV-Visible-NIR spectroscopy was used to study the sample and its leached products in the 200-800 nm wavelength region. Oxygen containing structures were observed in the 1800-1000 cm-1 zone, aliphatic hydrogen in the 2920-2800 cm-1 zone, aromatic outof- plane structure in the 900-670 cm-1 zone. A great abundance of C=C structure was noticed at 1600 cm-1 region, while clay and silicate minerals were identified in the 540 cm-1 and 1030 cm-1 region. With chemical leaching silicate bands showed a decrease in intensity and were least for EDTA and HF leached samples. The UV-Visible -NIR spectrum showed absorption maximum at 235-270 nm and was shown a red shift with leaching. The II-II* electronic transitions of the poly-nuclear aromatic hydrocarbons was responsible for the absorption at 680 nm. The weak bands observed in the visible region (400-500 nm) were due to the presence of SO2 in the sample and decreased with chemical leaching. It was evident from the results that amongst the leachants used, hydrofluoric acid and acid mixture had significant effect in removing the mineral matter and oxygenated functional groups. -
Bio-demineralization of Indian bituminous coal by Aspergillus niger and characterization of the products
The effect of demineralization on an Indian bituminous coal has been investigated by filamentous fungus Aspergillus niger. X-ray diffraction profile reveals the presence of inorganic components in the sample. Bio-Solubilization using Aspergillus niger significantly reduced the ash content in the coal sample (10.23wt% to 5.21wt %). Leaching process removed silicate and pyrite minerals where as aluminates were decreased considerably. The carbon content showed an increase of 19.94% where as the oxygen content decreased by 52.3%. During biosolubilization the fungus produced acids like gluconic acid, oxalic acid and citric acid along with oxalates which are responsible for the demineralization in coal by the formation of mineral salts. The broad diffraction peak at 2?~25.5 is due to the crystalline carbon in the sample which is mainly due to the typical (002) plane reflection of graphite. -
Demineralization of sub-bituminous coal by fungal leaching: A structural characterization by X-ray and FTIR analysis
The filamentous fungi, A. niger, A. flavus and Penicillium spp were studied for their ability to demineralise the low rank Indian coals. The FTIR spectra of coals showed the presence of stretching vibrations of -OH bond, aliphatic -CH, -CH2 and - CH3 absorptions, C=C and -CH of aromatic structure and mineral groups. X-ray analyses revealed that coal consists of crystalline carbon of turbostratic structure. The average lateral sizes (La), stacking height (Lc) and the interlayer spacing (d002) of the crystallite structure were calculated which ranged from 343.64 to 1.5, 223.20 to 22.54 and 3.35 to 3.60respectively. The structure of coal was modified to a product similar to that of pure graphite after leaching with Penicillium spp. Scanning electron microscopy (SEM) analysis of coal revealed a layer like structure on the surface. -
Biological elimination of minerals from high ash coal by Aspergillus-like fungi
Efficiency of filamentous fungi such as Aspergillus niger on the bio-liquefaction of low rank Indian coals, its chemical composition, surface characteristics of the products and the microbial mechanisms of coal conversion were studied. Virgin and bio-liquefied/solubilized coal samples were characterized using FT-IR, Scanning electron microscopy and CHNS and proximate analysis. The micrographs were bright field and reveal several features correspond to the mineral grains comprising of aluminium, silicates and calcites. The absence of some morphological features corresponds to inorganic elements in residual samples which confirm demineralisation with the possible formation of respective Aluminum and Silicate complexes. The change in absorption of mineral matter functional group of these coal samples were studied using Fourier transform infra red spectroscopy (FT-IR). From the proximate analysis it was found that the ash content decreased by 76% when treated with fungal culture. Global Science Publications. -
Systematic investigations of graphene layers in sub-bituminous coal
Coal is the plentiful and widely and universally used fuel. However, its structural characteristic makes a perception that it is only worthwhile for generating energy via combustion. Herein we report a simple method to synthesize nanometre-sized graphene sheets with amorphous carbon addends on the edges from sub-bituminous coal. The X-ray analysis reveals the presence of crystalline carbon in the amorphous background. The average number of carbon atoms and aromatic layers was estimated as ?21 and 8. The interlayer spacing d 002 for the aromatic lamellae of samples leached using HF and acetic acid, are found to be 0.352 and 0.376 nm, respectively. The oxidation of coal structure resulted in nanometre sized graphene having lateral size of 4.19 nm and stacking height of 2.3 nm. The Raman spectrum analysis confirmed the formation of finite sized, less defective graphene nanolayers with leaching. The crystalline carbon within the coal matrix displaced with chemical leaching, resulting nano-meter sized graphene sheets. The results also established that with HF leaching, carbon in coal becomes more stacked and ordered compared to organic acid leached coal. 2014 Pleiades Publishing, Ltd. -
Leaching of minerals in subbituminous Indian coal and characterisation of the products by SEM
Coal is chemically and physically a complex and heterogeneous material, consisting of organic and inorganic mineral constituents. Presence of minerals in excess will pollute water, air and soil. Concerted efforts are needed to reduce 'ash forming' inorganic elements and to develop clean methods of using coal. This paper reports the demineralization of sub bituminous coal with EDTA, HCl, HF, chloroform and acid mixture. The residual coal from each treatment was analyzed using Scanning Electron Microscopy (SEM) and Ultimate analysis. All the micrographs were bright field and revealed several features corresponding to the mineral grains. It comprised of lithophiles like aluminium, silicates and calcium. The absences of some morphological features correspond to inorganic elements in residual coal samples confirming 'demineralization'. This result was further confirmed with the CHNS analysis. It was evident from the results that amongst the leachants used, Hydrofluoric acid and acid mixture had significant effect in removing the mineral matter, sulphur and oxygenated functional groups. Global Science Publications. -
Study of stacking structure of amorphous carbon by X-ray diffraction technique
Random layered (graphene) structural parameters of the coals such as aromaticity fa, coal rank, number of carbon atoms per aromatic lamellae (n), lateral size La and stacking height Lc are determined using X-ray diffraction technique (XRD). It is found that the structural parameters like fa & Lc increases, where as interlayer spacing d002 decreases with increase in carbon content, aromaticity and coal rank. The number of layers and average number of carbon atoms per aromatic graphene are found to be varying from 7 to 8 and 16-21 for the coal samples with carbon content of 72- 77.4%. A good linear relationship exists between number of layers and stacking height of the aromatic lamellae in coal. 2012 by ESG. -
Chemical leaching of an Indian bituminous coal and characterization of the products by vibrational spectroscopic techniques
High volatile bituminous coal was demineralized by a chemical method. The vibrations of the "aromatics" structure of graphite, crystalline or non-crystalline, were observed in the spectra at the 1600 cm -1 region. The band at 1477 cm -1 is assigned as VR band, the band at 1392 cm -1 as VL band and the band at 1540 cm -1 as GR band. Graphite structure remains after chemical leaching liberates oxygenated functional groups and mineral groups. The silicate bands between 1010 and 1100 cm -1 are active in the infrared (IR) spectrum but inactive in the Raman spectrum. Absorption arising from C-H stretching in alkenes occurs in the region of 3000 to 2840 cm -1. Raman bands because of symmetric stretch of water molecules were also observed in the spectrum at 3250 cm -1 and 3450 cm -1. Scanning electron microscopy analysis revealed the presence of a graphite layer on the surface. Leaching of the sample with hydrofluoric acid decreases the mineral phase and increases the carbon content. The ash content is reduced by 84.5wt% with leaching from its initial value by mainly removing aluminum and silicate containing minerals. University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg 2012. -
Facile synthesis of preformed mixed nano-carbon structure from low rank coal
Coal is a natural energy resource which is mainly used for energy production via combustion. Coal has nanocrystals embedded in it, formed during the coalification process, and is an ideal precursor for nano-carbon dots and diamonds. Herein, we report a facile top-down method to synthesise nanodots and diamonds of the size of 5 nm to 10 nm from three different types of coal by simple chemical leaching. TEM analysis revealed the formation of a mixture of carbon dots, graphene layers, and quantum dots in bituminous coal and sub-bituminous coal. Raman analysis confirmed the existence of synthesized nano-diamond and nano-carbon mixed phase with defects associated with it. It is concluded that graphene quantum dots, nano-diamonds, graphene sheets and carbon dots present in coal can be extracted by simple chemical treatment. These structures can be tuned to photoluminescent material for various optoelectronic applications or energy harvesting devices like super capacitors. 2018. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License. -
Tunable direct band gap photoluminescent organic semiconducting nanoparticles from lignite
Fluorescent organic semiconducting dots (OSDs) with tunable particle size and surface functionality are synthesized from lignite by chemical oxidation method followed by ultra-sonication techniques and dialysis. The defects and oxygen functionalities play a vital role in the photoluminescent property of the synthesized nanoparticles along with quantum confinement effect. These nanomaterials are suitable for imaging and chemical sensing applications as there is no photobleaching and quenching even after a continuous UV exposure of 24 hours and storage of 2 years. The excellent excitation dependent luminescence of the synthesized carbon dots can be utilized for making a low-cost carbon-based sensor for Cu2+ metal ions sensing. The OSDs show good ratiometric fluorescent sensing and can be used as a reliable probe for the detection of Cu2+ ions. They exhibit excellent detection limit of copper ion in acidic solution to a very low concentration of 0.0089 nM. The fluorescent nanodots synthesized from such an abundant and cost-effective precursor exhibiting high copper ion sensitivity is being reported for the first time. 2017 The Author(s). -
Tailoring of low grade coal to fluorescent nanocarbon structures and their potential as a glucose sensor
Lignite is an abundantly utilized feedstock for the facile synthesis of fluorescent carbon dots and carbon nanomaterials. Its value is appreciated as an energy source for combustion for long time. Herein we report a novel top-down strategy to synthesis lignite based fluorescent nano carbon structures by combined acidic oxidation and chemical reflux. The nanocarbon crystallites in lignite are converted to oxygenated nano carbon dots and graphene sheets. They exhibited stable fluorescence property in the visible region depending on their size, functionalities and defects which were highly stable in all the pH conditions. These nanocarbon structures are an effective probe for fluorescent sensing of label-free and selective detection of glucose ions with detection limit as low as 0.125 mM, promising real-world sensor applications. These findings establish a scalable method for the production of fluorescent carbon based glucose sensor from lignite. 2018, The Author(s). -
Characterization of diesel soot from the combustion in engine by X-ray and spectroscopic techniques
Carbon nanomaterials formed during the combustion of Diesel inside engine is characterized by X-ray diffraction (XRD) and spectroscopic techniques. The soot are collected from the Engine and washed with Acetone. Carbon Nanomaterials produced from diesel soot show the morphology of carbon nanospheres mixed with carbon nanotubes. X-ray diffraction investigation shows the presence of carbon nanotubes in association with amorphous nanomaterial. EDS analysis of Diesel soot indicates that the soot particles to be composed of primarily carbon and oxygen along with hydrogen. NMR spectrum of the soot reveals significant aliphatic component with predominance of methyl and methylene groups on ? and ? positions to aromatic rings. There is significant fraction of hydrogen on the ? position at 0.864 ppm, which suggests the existence of large aliphatic chains or saturated rings joined to aromatic rings. The IR spectrum shows characteristic signals in the region 1700-1000 cm -1, where the most important one correspond to C=O stretching of carboxylic acids at 1639 cm -1, C=C stretching of aromatic groups at 1533 cm -1, and aliphatic C-H plane deformation of CH 2/CH 3 groups at 1380 cm -1 and 1445 cm -1 respectively. 2012 by ESG. -
Cobb douglas production function analysis of total factor productivity in Indian textile industry in the post multi-fiber agreement (MFA) period
Internnational tradee in textiles aand clothing wwas governedd by the systemm of bilateral quotas undeer the MMulti Fibre AgreementA (MMFA) since 11973 and thiss agreement has been repeplaced by thhe Agreeement on Texxtiles and Cllothing (ATC)C) from Januaary 1, 2005. The dismanntling of quotta restricctions had brrought about a significant change in thee structure off worldwide trrade in textilees as theere are no quuota barriers for the exporrt of textiles aand apparelss and the hithherto protecteed textilee industry wouldw be exposed to interrnational commpetition. It was widely believed annd highliighted in mosst of the studies that develloping economies, especiaally India andd China woulld be thee major gaineers in the neww policy regiime. In view of the changged trading ennvironment foor textilee trade, it wass considered important to analyze the immpact of quotta removal onn Indian textille industry, especiallyy with respecct to the prodductivity on thhis sector. Thee study has coonsidered fouur sub seectors of Indiian textile inddustry as givven in the Annnual Survey oof Industries, viz, Spinningg, Weavving and Finiishing of Texxtiles, Manuffacture of Other Textiles,, Manufacturre of Wearinng Apparrels and Manufacture off Crocheted aand Knitted Fabrics. Esstimates of CCobb Douglaas produuction function shows that the removal of textile quoota had impaccted all the foour sub sectorrs considdered in the study.s The imppact of quota removal on pproductivity iis positive andd significant iin the caase of spinninng, weaving aand finishingg of textiles ass well as in tthe manufactuure of wearinng apparrels. In the casec of mannufacture of other textiless and the mmanufacture oof knitted annd crochheted fabrics, the quota duummy coefficient is negatiive and signifificant at onee percent leveel. This sshows that thhe removal ofof quota restrrictions have adversely immpacted the ooutput of thesse sectorrs. 2020, North Carolina State University. All rights reserved. -
Smart songs selection in playlists using parallel k-means clustering
Most songs today are of different tempo, pitch and time signature. In a music player application, the typical shuffle picks the succeeding song or preceding song at random with no parameters to choose the songs. Different songs from different genres can have a tempo range anywhere between forty beats per minute and three hundred beats per minute. In this paper, the quick and efficient parallel k means clustering algorithm is implemented in Hadoop on the million-song dataset subset to form clusters for the songs based on tempo and pitch. The aim of this paper is to reduce the variation that occurs when a typical shuffle picks the succeeding song at random. This variation can be in the form of tempo or other parameters. The formation of clusters and intern the reduction in the variation of tempo can be used in a new 'smart shuffle'. After the clusters have been formed, the smart shuffle picks the songs within that specific cluster. This paper aims at reducing the variation by 50%. This would have many musical benefits and would also be more pleasing to the listener. 2018 IAEME Publication. -
Synthesis and characterization of porous, mixed phase, wrinkled, few layer graphene like nanocarbon from charcoal /
Russian Journal Of Physical Chemistry A, Vol.89, Issue 13, pp.2438-2442, ISSN No: 0036-0244. -
Export performance of Indian textile industry in the post multi fibre agreement regime /
Artha Journal Of Social Science, Vol.13, Issue 4, pp.63-86, ISSN No: 0975-329X.