Journal Articles
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Item Forestry reclamation of disturbed surface mine lands(2011) Tripathi, A.K.; Bhattacharya, J.; Pal, S.K.The goal of forestry reclamation is creation of naturally stable and productive forests on disturbed surface mine soil in as little time as possible which generate value for their owners and provide watershed protection, wildlife habitat, and other environmental services. This paper describes research conducted to study the forestry reclamation of disturbed surface mine lands. Soil data for forestry reclaimed land in Rheinish lignite area has also been compared to that of adjacent undisturbed forestry land to investigate the effectiveness of reclamation and soil management operations in restoring the disturbed surface mine land similar to adjacent undisturbed land.Item A study on loose material filled PVC props as an alternative to conventional wooden supports(2011) Pal, S.K.; Kedia, R.; Trivedi, A.K.This paper describes the research conducted to design new type of props using PVC pipe and loose particles (cohesive and non-cohesive) as fill material. The design of the props is such that load is applied only to the inner core, of which a part of it is borne by the PVC because of the friction between inner and outer pipe. Rest of the load is transferred to the core, which pressurizes the pipe from inside. The reasoning behind constructing such props is that a pipe that is internally pressurized will be more rigid towards bending and hence take more load. This paper discusses experimental research work carried out on small as well as large scale props by varying L/D ratio (fixed in case of large scale props) and the type of fill material (cohesive and noncohesive) for testing their ultimate strength by loading them in different manners.Item Reclamation and management of disturbed surface mining areas for agricultural purpose with emphasis on concurrent reclamation(2012) Tripathi, A.K.; Bhattacharya, J.; Pal, S.K.The extraction of natural resources has significant influence on the surrounding landscape and environment. Consequently in modern surface mines, reclamation is considered an important part of mining activities and is given as much importance as the extraction itself. The goals of reclamation are also integrated in the overall operational concept of surface mining. This paper discusses in detail the operations carried out to reclaim and manage the disturbed surface mine lands for agricultural purpose. Reclamation operations carried out in lignite mines in Germany for restoration of disturbed surface mining areas for agricultural purpose are also described.Item Postmining soil development on spreader reclaimed land for agricultural purpose in Rheinish lignite area, Germany(2012) Tripathi, A.K.; Bhattacharya, J.; Pal, S.K.The goal [I] of agricultural reclamation in Rheinish lignite area, Germany is to restore arable soils with high capacity for crop production which ensures a permanent productivity with normal cultivation irrespective of current crop harvesting. Reclamation forms an integral component of the mine planning process and restoration of area disturbed due to mining in the region is given as much importance as the extraction of lignite itself. The soil materials for agricultural postmining land use are carefully selected and special care is taken while handling the soil so as to preserve the basic qualities. In this research, data obtained from agricultural reclaimed lands of different ages in Rheinish lignite area, Germany for various soil physical, chemical and biological parameters have been compared with nearby undisturbed soil data to study the postmining soil development with time.Item Incorporating local image structure in normalized cut based graph partitioning for grouping of pixels(2013) Sen, D.; Gupta, N.; Pal, S.K.Graph partitioning for grouping of image pixels has been explored a lot, with normalized cut based graph partitioning being one of the popular ones. In order to have a credible allegiance to the perceptual grouping taking place in early human vision, we propose and study in this paper the incorporation of local image structure/context in normalized cut based graph partitioning for grouping of image pixels. Similarity and proximity, which have been studied earlier for grouping of image pixels, are only two among many perceptual cues that act during grouping in early human vision. In addition to the said two cues, we study three other such cues, namely, common fate, common region and continuity, and find indications of local image structure utilization during grouping of image pixels. Appropriate incorporation of local image structure/context is achieved by representing it using neighborhood in the form of histogram and fuzzy set. We demonstrate both qualitatively and quantitatively through experimental results that the incorporation of local image structure improves performance of grouping of image pixels. © 2013 Elsevier Inc. All rights reserved.Item Model studies on the efficiency of gravity blind backfilling method and evaluation of a pre-jamming indication parameter(CAFET INNOVA Technical Society 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2016) Pal, S.K.; Mukhopadhyay, S.K.; Panda, S.; Tripathi, A.K.This paper discusses experimental research on a fully transparent scaled model of a section of a Bord and Pillar mine working carried out to study in detail the effectiveness of hydraulic blind backfilling as a solution to reduce subsidence problem above old underground water-logged coal mines. The relative influence of sand and water flow rates on the areas of filling from a single inlet point has been studied in detail. Automatic data acquisition system was installed in the model to continuously record the sand and water flow rates along with the inlet pressure of slurry at the entrance of the model. Pressure signature graphs have been plotted directly with the help of computer. Pressure signature analyses for various slurry flow rates and sand concentrations have been carried out. Investigation has also been carried out on evaluation of a pre-jamming indication parameter, which could be used for indication of the final stage of filling. © 2016 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Tuning the self-assembly and photophysical properties of bi-1,3,4-thiadiazole derivatives through electron donor-acceptor interactions and their application in OLEDs(Royal Society of Chemistry, 2017) Yadav, A.K.; Pradhan, B.; Ulla, H.; Nath, S.; De, J.; Pal, S.K.; Satyanarayan, M.N.; Ammathnadu Sudhakar, A.S.We report several shape anisotropic molecules that contain two centrally placed 1,3,4-thiadiazole units, which vary from each other with respect to the number and length of the flexible chains at the termini. The number, position and length of the peripheral chains connected to the termini showed an impact on the thermal behavior of these compounds. The compounds with two terminal tails exhibited an enantiotropic smectic C phase, whereas the compounds with four terminal tails turned out to be crystalline. Surprisingly, among the compounds with six terminal tails, only the compound with a longer terminal chain exhibited a columnar phase with oblique symmetry. It is also to be noted that only compounds with six terminal chains exhibited gelation in long chain hydrocarbons. The xerogel of the hexacatenar with six n-decyloxy chains showed an entangled network of nanofibers of several micrometers in length. The aggregation behavior of the hexacatenar in the hydrocarbon solvent is mainly supported by the attractive ?-? interactions of the aromatic cores and the van der Waals interactions offered by the peripheral flexible tails. The emission behavior is dependent on the number of peripheral tails and not on the length. Furthermore, one of the hexacatenars exhibited solvatochromic emissive behavior. This molecular design helps in the development of long molecular nanowires with a central conducting core and insulating peripheral sheath, which will be helpful for the application in organic electronic devices. The application potential of the columnar liquid crystal material was tested by the fabrication of organic light emitting diodes (OLEDs) either as a single emissive material or as a guest material in a host polymer. Higher efficiency and brightness were noticed in the host guest OLED, which exhibited a technologically important bright blue emission. © 2017 The Royal Society of Chemistry.Item Prediction of physico-mechanical properties of rocks using dominant frequency of vibration during rotary drilling(Science Publishing Corporation Inc ijet@sciencepubco.com, 2018) Lakshminarayana, C.R.; Tripathi, A.K.; Pal, S.K.In this study, an attempt is made to estimate some of the important physico-mechanical properties of sedimentary rocks using second-order multiple regression mathematical models. For model development, different drilling operational parameters and equivalent dominant frequencies of vibration excited at spindle head during rotary drilling were used. The prediction capacity or performance of the developed models was evaluated by using variance account for (VAF), root mean square error (RMSE) and mean absolute percentage error (MAPE).In addition, the strength of the relationship between measured and predicted value of rock properties are also checked using the Pearson correlation coefficient. Prediction performance indicators and correlation coefficients showed that the prediction model developed through the approached method can be successfully used for preliminary investigation of physico-mechanical properties of rocks which are often used as a primary data for the design of mining and civil engineering projects. © 2018Lakshminarayana C. R et. al.Item Estimation of Rock Strength Properties Using Selected Mechanical Parameters Obtained During the Rotary Drilling(Springer, 2019) Lakshminarayana, C.R.; Tripathi, A.K.; Pal, S.K.During the preliminary stage of rock engineering projects, the estimation of mechanical properties of rocks is most often required. The requirement of a large number of high-quality rock core samples is the major drawback when the mechanical rock properties are to be determined in a well-established rock mechanics laboratory. In this study, an attempt is made to estimate the uniaxial compressive strength and Brazilian tensile strength of sedimentary rocks using the selected mechanical drilling operating parameters obtained during the rotary drilling. The operating measured parameters such as the weight on bit or thrust and the vibration frequency induced at machine or drill head were acquired using the drill tool dynamometer and sound/vibration data acquisition system, respectively. The mathematical models were developed considering the drilling operational parameters (drill bit diameter, drill bit speed and penetration rate) and measured mechanical parameters (thrust and vibration frequency). The prediction potential of the developed models was assessed by the prediction performance indices. The outcome results revealed that the developed mathematical model using the approached method is significant and can be conveniently used for the estimation of mechanical properties of rocks during the rotary drilling. © 2019, The Institution of Engineers (India).Item Characteristics of vibration at failure and its relation to rock properties during tensile failure(Books and Journals Private Ltd., 2020) Pal, S.K.; Pandey, N.; Tripathi, A.K.The paper describes the study carried out to determine the relationships between the amount of vibrations that happen inside the rock at the time of failure under tensile loading and different rock properties such as uniaxial compressive strength, uniaxial tensile strength, Young’s modulus, cohesion, angle of internal friction and density. It is then tried to interpret what are the factors that affect the vibrations and the time to failure. To capture the vibrations piezoelectric sensors are used which capture the acoustic signals and convert them into electric signals. With the help of Picoscope, it was then possible to recover the acoustic signals. At the time of failure, the peak voltage (h) was recorded along with the span of time the rock took to fail (w). The h/w ratio was then obtained and used to relate it with different rock properties. h/w ratio is the measure of how much vibrations happen inside the rock and for what amount of time. It was observed to be highly related to uniaxial tensile strength, angle of internal friction and rock density. © 2020, Books and Journals Private Ltd.. All rights reserved.