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International Journal of Coal Science & Technology 2024年第2期11卷 111-122页

作者： Heena dhawan D.K.Sharma ANRF Ministry of ScienceNew DelhiIndia Department of Energy Science and Engineering Indian Institute of Technology DelhiNew Delhi 110016India

Chemical leaching of coals would be required to produce cleaner coals for some special applications where physical benefi-ciation may not be effective *** would also help in recovering Li and rare earth metals besides in the sequestration of CO_(2).About 20 Indian coals having complexly distributed moderate to high ash contents were sequentially treated with various alkali–acid such as NaOH-HCl,HF,HCl,HCl-HF,and NaOH-HCl-HF *** aimed to establish and design the best stepwise sequential process for the highest degree of demineralisation through a chemical leaching *** and process intensification studies were carried *** than 80%demineralisation of Madhaipur and Neemcha coals was observed using the best sequential treatment designed *** repeated stepwise treatment of the alkali and the acid was also studied,which was found to significantly enhance the degree of demineralisation of *** integrated process of alkali–acid leaching followed by solvent extraction(Organo-refining)and vice versa of the treated coal was also studied for producing cleaner coals.

关键词： Alkali–acid leaching Demineralisation Integrated process Rare earth elements

Secure and resilient improved image steganography using hybrid fuzzy neural network with fuzzy logic

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Journal of Safety Science and Resilience 2024年第1期5卷 91-101页

作者： Sachin dhawan Hemanta Kumar Bhuyan Subhendu Kumar Pani Vinayakumar Ravi Rashmi Gupta Arun Rana Alanoud Al Mazroa Dorset College King George BlvdSurreyBritish ColumbiaCanada Department of Information Technology Vignan’s Foundation for ScienceTechnology and Research(Deemed to be University)Andhra PradeshIndia Krupajal Computer Academy Biju Patnaik University of Technology(BPUT)Rourkela 751002India Center for Artificial Intelligence Prince Mohammad Bin Fahd UniversityKhobarSaudi Arabia NSUT East Campus(Formerly AIACTRDelhi 110031India(Affiliated to Guru Gobind Singh Inderaprastha University))Dwarka 110078India Department of Computer Science and Engineering Galgotias College of Engineering and Technology Greater Noida 201310Uttar PradeshIndia Department of Information Systems College of Computer and Information SciencesPrincess Nourah bint Abdulrahman University(PNU)P.O.Box 84428Riyadh 11671Saudi Arabia

The exponential growth in communication networks,data technology,advanced libraries,and mainly World Wide Web services has played a pivotal role in facilitating the retrieval of various types of information as ***,this progress has also led to security concerns related to the transmission of confidential ***,safeguarding these data during communication through insecure channels is crucial for obvious *** emergence of steganography offers a robust approach to concealing confidential information,such as images,audio tracks,text files,and video files,in suitable media carriers.A novel technique is envisioned based on back-propagation *** to the proposed method,a hybrid fuzzy neural network(HFNN)is applied to the output obtained from the least significant bit substitution of secret data using pixel value dif-ferences and exploiting the modification *** simulation and test results,it has been observed that the proposed methodology achieves secure steganography and superior visual *** the experiments,we observed that for the secret image of the cameraman,the PSNR&MSE values of the proposed technique are 61.963895 and 0.041361,respectively.

关键词： Image enhancement Image processing Steganography Deep learning Fuzzy neural combination

Modelling of electronegative collisional warm plasma for plasma-surface interaction process

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Plasma Science and Technology 2021年第4期23卷 48-54页

作者： Rajat dhawan Hitendra K MALIK Plasma Science and Technology Laboratory Department of PhysicsIndian Institute of Technology DelhiNew Delhi—110016India

An electronegative collisional plasma having warm and massive positive ions,non-extensive distributed electrons and Boltzmann distributed negative ions is modelled for the plasma-surface interaction process that is used for the surface *** the sheath formation is evaluated through the Bohm’s criterion,which is found to be modified,and the variation of the sheath thickness and profiles of the density of plasma species and the net space charge density in the sheath region in addition to the electric *** effect of ion temperature,nonextensivity and collisional parameter is examined in greater detail considering the collisional cross-section to obey power-law dependency on the positive ion *** positive ions are found to enter in the sheath region at lower velocities in the collisional plasma compared to the case of collision-less plasma;this velocity sees minuscule reduction with increasing *** increasing ion temperature and collisional parameter lead to the formation of sheath with smaller thickness.

关键词： electronegative sheath ion temperature non-extensivity sheath thickness power-law dependency collisions

Noninvasive biomarkers in non-alcoholic fatty liver disease:Current status and a glimpse of the future

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World Journal of Gastroenterology 2014年第31期20卷 10851-10863页

作者： Emer Fitzpatrick Anil dhawan Paediatric Liver GI and Nutrition Centre King’s College London School of Medicine at King’s College Hospital

The development of non invasive biomarkers of disease has become a major focus of interest in nonalcoholic fatty liver disease(NAFLD). The large prevalence of the disease and the invasive nature of the investigation means that screening with liver biopsy is *** addition to screening, the differentiation of those with simple steatosis vs steatohepatitis and fibrosis is clinically important as the prognosis of each *** biomarkers may be a combination of simple markers derived from large data sets or direct markers of disease activity. Serum markers of inflammation,apoptosis and oxidative stress in addition to fibrosis have been extensively studied in patients with *** techniques such as transient elastography,magnetic resonance elastography and acoustic radiation force imaging are becoming more established as noninvasive methods of detecting fibrosis in a variety of chronic liver conditions in addition to NAFLD. Newer high throughput methods such as proteomics and glycomics allow the nonhypothesis-driven identification of novel markers and may also potentially contribute to our understanding of the pathogenesis of the *** review addresses some of the methodological issues which need to be considered in the search for the ideal biomarker. It is likely that a combination of serum biomarkers and techniques such as transient elastography may provide the optimal diagnostic discrimination however this remains to be proven in large studies.

关键词： Noninvasive biomarkers Nonalcoholic fatty liver disease Fibrosis

Advances in the chemical leaching (inorgano-leaching), bioleaching and desulphurisation of coals

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International Journal of Coal Science & Technology 2019年第2期6卷 169-183页

作者： Heena dhawan Durlubh Kumar Sharma Centre for Energy Studies Indian Institute of Technology Delhi Hauz Khas New Delhi 110016 India

Coal still remains an important source of power generation world over. Along with its usage, comes unwanted generation of noxious gas emissions, toxic metal releases into wastewater and other pollutants which ultimately lead to environmental concerns. So cleaning of coal through physical or chemical processes becomes utmost important. There are several coals which cannot be cleaned by physical beneficiation techniques to produce low ash cleaner coals. Such coals can be cleaned only through chemical cleaning techniques. The present paper reviews the chemical demineralisation and desulphurisation of coals over the years using various inorganic and organic acids, alkalis, oxidants, leachants and various acids and alkali-acid combinations to reduce the ash and sulphur contents in coals. As high as 90% demineralisation and desulfurization could be achieved with the use of these cheap inorganic acids as compared to the expensive solvents used for solvent extraction processes, a parallel approach of cleaning and refining coals.

关键词： Coal Demineralisation Desulfurization Acids Alkalis

Insights from principal component analysis applied to Py-GCMS study of Indian coals and their solvent extracted clean coal products

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International Journal of Coal Science & Technology 2021年第6期8卷 1504-1514页

作者： Abyansh Roy Heena dhawan Sreedevi Upadhyayula Hariprasad Kodamana Department of Chemical Engineering Indian Institute of Technology DelhiHauz KhasNew Delhi 110016India

The present work aims at studying five Indian coals and their solvent extracted clean coal products using Py-GCMS analysis and correlating the characterization data using theoretical principal component *** pyrolysis products of the original coals and the super clean coals were classified as mono-,di-and tri-aromatics,while other prominent products that were obtained included cycloalkanes,n-alkanes,and alkenes ranging from C_(10)-C_(29).The principal component analysis is a dimensionality reduction technique that reduced the number of input variables in the characterization dataset and gave inferences on the relative composition of constituent compounds and functional groups and structural insights based on scores and loading plots which were consistent with the experimental ***-FTIR studies confirmed the reduced concentration of ash in the super clean coals and the presence of *** Py-GCMS data and the ATR-FTIR spectra led to the conclusion that the super clean coals behaved similarly for both coking and noncoking coals with high aromatic concentrations as compared to the raw *** lignite super clean coal was found to show some structural similarity with the original coals,whereas the other super clean coals showed structural similarity within themselves but not with their original coal samples confirming the selective action of the e,N solvent in solubilizing the polycondensed aromatic structures in the coal samples.

关键词： Indian coal Super clean coals Pyrolysis PCA ATR-FTIR Py-GCMS

Liver transplantation for pediatric inherited metabolic liver diseases

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World Journal of Hepatology 2021年第10期13卷 1351-1366页

作者： Sunitha Vimalesvaran Anil dhawan Paediatric Liver GI and Nutrition Center King's College HospitalLondon SE59RSUnited Kingdom

Liver transplantation(LT)remains the gold standard treatment for end stage liver disease in the pediatric *** liver based metabolic disorders(LBMDs),the decision for LT is predicated on a different set of *** improved outcomes post-transplantation,LT is no longer merely life saving,but has the potential to also significantly improve quality of *** review summarizes the clinical presentation,medical treatment and indications for LT for some of the common *** also provide a practical update on the dilemmas and controversies surrounding the indications for transplantation,surgical considerations and prognosis and long terms outcomes for pediatric LT in *** progress has been made in understanding these diseases in recent years and with that we outline some of the new therapies that have emerged.

关键词： Pediatric metabolic liver disease Liver transplantation Liver based metabolic disorders Inherited Cell therapy Gene therapy

Design of experiments to optimize the extraction parameters of a power grade Indian coal

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International Journal of Coal Science & Technology 2018年第4期5卷 417-429页

作者： Heena dhawan Sreedevi Upadhyayula D.K.Sharma Centre tor Energy Studies Indian Institute of TechnologyNew Delhi 110016India Department of Chemical Engineering Indian Institute of TechnologyNew Delhi 110016India

Low grade high ash coals with difficult physical washability characteristics require chemical cleaning techniques such as solvent extractio n to obtain super clean coal with lower ash conte ***,an In di an low grade coal has ash con tent around 44%-50%and there is a need to maximize its solvent extraction yield so as to make this power grade coal industrially *** paper highlights the use of definitive screening design and response surface methodology to extract the maximum organic matter from Kedla coal using ethylenediannnine(EDA)and N-methyl pyrollidone(NMP)as solvents under mild atmospheric pressure *** coal was pre-treated with acetic acid before extractions were carried *** parameters such as the acid pre-treatment time,acid concenmion,particle size,the co-solvent concentratio n and the solvent concentration were optimized in this *** this design of experimenls technique about 40%of the organic matter with minimal ash(less than 2%)content was「endered extractable unlike the already postulated designer solvent system—e,N system(*** containing small amount of EDA)that uses coal to solve nt ratio as 1:17(wt/vol)and coal to co-solvent ratio as 1:l(wt/vol)thus only giving 19%extraction ***,the present design of experimetechnique helps in conserving the number of experimems for process intensification.

关键词： Coal Extraction yield Acid pre-treatment Definitive screening design Response surface methodology

Effect of vitamin B12 deficiency anemia on peripapillary retinal nerve fiber layer

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International Journal of Ophthalmology(English edition) 2021年第9期14卷 1424-1429页

作者： Sushobhan Das Gupta Tarannum Shakeel Aeshwarya dhawan Aashish Kakkar Department of Ophthalmology Shri Guru Ram Rai Institute of Medical and Health SciencePatel NagarDehradun 248001India

AIM:To evaluate the effect of vitamin B12 deficiency anemia(BDA)on peripapillary retinal nerve fiber layer thickness(RNFLT)using spectral domain optical coherence tomography(SD-OCT),and to determine any correlation arising ***:In this cross-sectional observational study,99 eyes of 50 BDA patients of age 18-65 y were compared with 100 eyes of 50 healthy control *** subjects underwent comprehensive clinical,ophthalmic,and hematological evaluation,followed by peripapillary RNFLT assessment using ***:The mean total,inferior,nasal,and temporal RNFLT were significantly lower in BDA group as compared to control group(P<0.05).The mean total,inferior and nasal RNFLT correlated significantly(P<0.05)with serum Hb%,B12 and mean corpuscular volume(MCV)level(r=0.310,0.435,-0.386 for total;r=0.932,0.481,-0.513 for inferior;r=0.344,0.254,-0.233 for nasal;respectively),while temporal and superior RNFLT quadrant did not show any correlation with any of the hematological parameters(r=0.144,0.167,-0.096;r=0.111,0.070,-0.099;respectively).The mean total RNFLT showed progressive thinning at par with the progression of anemia,except in very severe BDA,where an inverse relationship was ***:The mean total,inferior,nasal,and temporal peripapillary RNFLT was significantly thinner in BDA *** RNFLT thinning seemed to proceed at par with the progression of severity of anemia,except in very sever *** assessment of peripapillary RNFLT may be crucial in BDA patients to prevent potential blinding *** RNFLT thinning in BDA patients should be considered in the differential diagnosis of other non-glaucomatous optic neuropathies,as well.

关键词： vitamin B12 deficiency anemia retinal nerve fiber layer spectral domain optical coherence tomography

Microwave-assisted reduction roasting–magnetic separation studies of two mineralogically different low-grade iron ores

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International Journal of Minerals,Metallurgy and Materials 2020年第11期27卷 1449-1461页

作者： Subhnit K.Roy Deepak Nayak Nilima Dash Nikhil dhawan Swagat S.Rath Mineral Processing Department CSIR-Institute of Minerals and Materials TechnologyBhubaneswar 751013India Department of Metallurgical and Materials Engineering Indian Institute of TechnologyRoorkee 247667India

The microwave-assisted reduction behaviours of two low-grade iron ores having a similar Fe content of 49wt%but distinctly different mineralogical and liberation characteristics were *** performances in terms of the iron grade and recovery as obtained from statistically designed microwave(MW)roasting followed by low-intensity magnetic separation(LIMS)experiments were *** respective optimum conditions,the titano-magnetite ore(O1)could yield an iron concentrate of 62.57%Fe grade and 60.01%Fe recovery,while the goethitic ore(O2)could be upgraded to a concentrate of 64.4%Fe grade and 33.3%Fe *** with the goethitic ore,the titanomagnetite ore responded better to MW *** characterization studies of the feed and roasted products obtained at different power and time conditions using X-ray diffraction,optical microscopy,vibrating-sample magnetometry,and electron-probe microanalysis explain the sequential reduction in the iron oxide ***,taking advantage of the MW absorbing character of the titano-magnetite ore,a blend of the same with the goethite-rich ore at a weight ratio of 60:40(O2:O1)was subjected to MW roasting that resulted in a concentrate of 61.57%Fe grade with a Fe recovery of 64.47%.

关键词： microwave reduction roasting titano-magnetite ore goethitic ore magnetic separation