IR@CIMFR - Central Institute of Mining and Fuel Research (CSIR)
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Soil Water content measurement using hyperspectral remote sensing techniques - A case study from north-western part of Tamil Nadu, India
No full textThis study examines the hyperspectral signatures (in the visible near-infrared(VNIR)–shortwave infrared (SWIR) regions of different samples of soilspossessing varying water content. Totally 82 soil samples with differing water contents were examined using a hyperspectral radiometer operating in the 350–2,500-nm range, and the spectral curves were obtained. Statistical analyses (linear regression and Pearson R) of the curves indicate that overall reflectanceincreases with decreasing water content in the sample within the saturation limit. ‘Depth at 1400 nm region’ as a dependable spectral parameter since there exists a good correlation compared to other parameters. Further the depth of absorption at 1400 nm region correlates well with water content even when the water content crosses the saturation limit. Based on these well-defined relations, it is inferred that hyperspectral radiometry in the VNIR and SWIR regions can be used to estimate the water content of soils
Role of Mn on reducibility and acidity of Cu-Zn promoted Co-Fe based bimetallic Fischer–Tropsch (F–T) catalysts
No full textThe effect of Mn is studied on Cu-Zn promoted alumina supported bimetallic (Co-Fe) FT catalyst. The catalysts have been prepared by wet impregnation technique on alumina with the respective metal nitrate solutions. Characterization of the catalysts have been carried out with XRD, H2-TPR, NH3-TPD and BET surface area. The results indicate that small addition of Mn enhances reducibility and minimizes the acidity of catalysts. This study will help to understand the contribution Mn for the development of efficient catalysts for Fischer-Tropsch synthesis
Prediction of ground behaviour for rock tunnelling
No full textStudies have shown that the ground behaviour for rock tunnelling depends on the rock mass strength and the in situ stresses. The rock mass strength, to a considerable extent, is governed by the presence of joints/discontinuities and their properties. Three aspects concerning the joints are primarily responsible for the reduction in the strength and are measurable in the field: (i) Joint frequency or number of joints per metre length in the direction of loading (Jn), (ii) orientation of critical joint set with respect to loading direction (β), and (iii) shear strength along the critical joint set (r). These three factors have been combined into another rock mass parameter, namely, the joint factor (Jf). Thus, joint factor has been selected as one of the parameters for developing the empirical correlation for predicting the ground behaviour. In addition to joint factor, the tunnel size and the tunnel depth are the other two involved parameters. Details of data and the process of developing the empirical correlations are discussed in the paper. The proposed empirical correlations for non-squeezing and squeezing ground behaviours have been validated by comparing the results with the observed data obtained from various sections of one Himalayan tunnel recently excavated in the state of Jammu and Kashmir in India
Study of temperature classification, spark ignition and drop test assessment on secondary cells for intrinsically safe equipment for explosive atmospheres
No full textIn any explosive atmosphere the cell/battery (pack of secondary cells) is used in handheld intrinsically safe (IS) apparatus. The cell is a rechargeable battery. Chemically similar cells of different makes were assessed for maximum surface temperature followed by the spark ignition test as per IS/IEC 60079-11. It was observed that the maximum surface temperature, open voltage, and short circuit current varied among cells having the same maker and nominal capacity. The cells were not vented or leaked or exploded during the short circuit test for determining the temperature class of cells. The cells with protection circuit had passed in spark ignition test but failed without protection circuit. It may be recommended that the cell should not be used without appropriate protection circuit even in a low power rating certified IS circuit for hazardous areas. A study was also carried out for spark ignition test on different cells connected to the IS protection circuit and the certified IS apparatus as a composite circuit. Each cell was encapsulated along with IS protection circuit and endured drop test successfully. This study was revealed that cell(s) may be used with appropriate IS protection circuit for IS apparatus/equipment
Monte Carlo simulation-based probabilistic health risk assessment of metals in groundwater via ingestion pathway in the mining areas of Singhbhum copper belt, India
No full textProbabilistic health risk assessment was conducted for metal exposure through groundwater in mining areas of Singhbhum Copper Belt, India. The concentrations of metals showed notable spatial variation exceeding drinking water standards at some of the locations. Hazard Quotient revealed that chronic risks to the local population were largely contributed by Mn, Co and As. The 95th percentiles of Hazard Index (HI) calculated using Monte Carlo simulations showed that the HI for male, female and child populations was 2.87, 2.54 and 4.57 for pre-monsoon, 2.16, 1.88 and 3.49 for monsoon and 2.28, 2.02 and 3.75 for post-monsoon seasons, respectively. The Hazard Indices indicated that amongst the populations, risk was greater for child population and considering the seasons the risk was higher during the pre-monsoon season. The sensitivity analysis suggested that concentration of metals in groundwater and exposure duration were 2 most influential input variables that contributed to the total ris
Investigation on the Combustion Behavior of Coal at Various Level of Washing in TGA and Drop Tube Furnace
No full textCleaning of coal resulted in ash reduction, heat value enhancement, increased reactive maceral content and change in ash composition influencing combustion performance. With washed fractions, trends of improved combustion behavior were observed in thermo-gravimetric analyser, which was not always reflected correspondingly in bench scale combustor, i.e. drop tube furnace (DTF). Lower burnout efficiency in DTF was observed when top port char particles were totally masked by defused mineral matter. Higher burnout efficiency was observed with tenui ballon/ sphere type of char structure partially covered by defused mineral matter. Overall improvement of combustion performance also led to CO2 emission reduction
Formation of thermogenic gases with coalification: FTIR and DFT examination of vitrinite rich coals
No full textThe evolution of thermogenic gases during coalification has not yet been theoretically attempted. Examinations on Indian Permian vitrinites of various ranks ranging from Cwt% 76 to 92 were performed. Fourier Transform Infra-red spectroscopy (FTIR) provided insight into the structural changes where the aliphatic CH increases with increase in percentage of carbon up to ~85% and then decreases. In contrast, the aromatic CH, the ratio of aromatic CH to aliphatic CH and aromaticity (fa) increase monotonically with the advancement of rank. A relationship between fa and atomic H/C ratio as fa = 1.12–0.45H/C was established to predict fa from elemental analysis. The structural data from FTIR served as an input to construct six representative hypothetical models of coal of varying Cwt% (76, 80, 83, 86, 87 and 89). Density Functional Theory (DFT) has been applied to these coal models and the formation of principal thermogenic gases, viz. CO2 for the low-(76%C)and CH4 for the high-rank (87%C), with simultaneous increase in the rank was demonstrated considering the smaller structural units extracted from the relevant coal models. The suggested reaction pathways are supported by the negative values of changes in free energies of the reactions computed from the Gaussian thermo-chemistry. The studies could, therefore, show that gas evolution as a natural (spontaneous) process with feasibility of rank advancement
Beneficial Poisonous Plants and their Therapeutic Values in Coal Capital City of Dhanbad, Jharkhand, India
No full textThe main objective of this study is to provide an insight into selective poisonous medicinal plants used in various beneficial treatments for the safety of the human health and culture which are now ignored and vanishing from Dhanbad district. The chemical constituents and phytochemical screening of plant species were done in the laboratory for their suitability in curing various ailments. Standard methods were used for identifying chemical species such as protein, carbohydrates, flavonoids, alkaloids, saponins, tannins, terpenoids, glycosides etc. Screening of these species were done for the various plant parts by established procedures using various media such as aqueous, chloroform, methanol, ethanol etc. Minimum Inhibitory Concentration (MIC) of leaf extracts of Nerium oleander (N. oleander) in acetone was found to be 30 mg/l while it was 100 mg/l in aqueous extract. No microbial lethality was seen. In Thevetia peruviana (T. peruviana), the concentration. of secondary metabolites followed methanol>aqueous>chloroform sequence. Presence of saponin and phalobatannin were not reported. Only phenols were seen. The bacterial inhibition rate in Ricinus communis (R. communis) was found to vary from 60-100% in Escherichia coli, 72-100% for Staphylococcus aureus (S. aureus), fungal inhibition against Aspergillus niger (A. niger) from 58-100% and antioxidant activity against 2, 2 Diphenyl, 1-picryl-hadrazyl-hydrate (DPHH) only 4%.
In this study therapeutic applications of three poisonous plants have been screened and selected for their use against various diseases once abundant in the coal city of Dhanbad, Jharkhand, India
Dynamic simulation approach to assess influence of charging parameters on blast induced ground vibration
No full textBlast induced ground vibration is one of the key concerns from safety view of nearby structures. There are many direct and indirect parameters responsible for blast induced ground vibration. Explosive parameters including its charging quantity and quality is one of them. Velocity of detonation of explosives, its interaction with rock strata and charging condition of a blasthole influences blast outputs in the form of fragmentation as well as undesirable effects like ground vibration, flyrock, air-over-pressure/noise etc. Researchers around the globe have established empirical formulations to investigate effects of explosive parameters on blast induced ground vibration. Following paper focused on investigating influence of charging parameters on blast induced ground vibration. Numerical simulation using dynamic modelling package of FLAC3D have been used for this. Signature hole geometry with rock properties and explosive properties in the form of detonation pressure has been modelled. Detonation pressure of the explosive was estimated from recorded in-the-hole velocity of detonation and density data for different explosive types. Damping parameters in the form of damping coefficient and frequency has been given to deplete blast vibration velocity for the medium. This was estimated by back calculation from recorded blast vibration data. Influence of hole diameter, distance of blast face from monitoring point, column length of explosive charge and charge distribution on blast induced vibration were assessed. Blast induced ground vibration in the form of history of velocity peaks has been plotted against dynamic time of blast wave propagation. Results of the dynamic simulation shows effects of hole diameter and charge column length on blast vibration in the same line with explosive weight per delay considered in USBM predictor equation. Investigation of effects of distance on blast induced vibration shows dependency of blast vibration on directional distance rather than radial distance. Charge distribution effects shows considerable reduction in blast vibration magnitude for distributed charge than full column charge
Some insights into fracturing of rock due to blasting in homogeneous material using particle flow code
No full textBlasting is a dynamic process in which rock is broken into smaller fragments, so that, it can be loaded and hauled with least effort and hence investment. The performance of the mine to mill system thus is mainly dependent on the fragmentation that in turn should be of optimum size. Understanding the fracture mechanics of a particular rock is thus quite imperative. Understanding the breakage of rockmass is very important because it ultimately helps in evaluating the performance of equipment vis-a-vis optimum fragment size that finally dictates the mine economics. The outcome of a blast is dependent on several variables belonging to rockmass and blast design. While blast design variables are controllable, the rock variables are of uncontrolled nature and hence difficult to simulate. One of the rock properties is its stiffness that has an impact on breakage of rock and is the subject of this paper. In order to determine the behaviour and fracturing during dynamic loading simple models representing blast benches were constructed using Particle Flow Code2D. Few simulations of throw, stemming movement and heave were made while varying the stiffness of material and keeping all other parameters constant. The paper thus reports the results obtained from such simulations