45 research outputs found

    Global nonlinear optimization for the estimation of static shift and interpretation of 1-D magnetotelluric sounding data

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    In the presence of conducting inhomogeneities in near-surface structures, apparent resistivity data in magnetotelluric sounding can be severely distorted. This is due to electric fields generated from boundary charges on surficial inhomogeneities. Such distortion persists throughout the entire recording range and is known as static shift in magnetotellurics. Frequencyindependent static shifts manifest as vertical, parallel shifts that occur in plots of the dual logarithmic scale of apparent resistivity versus time period. The phase of magnetotelluric sounding data remains unaffected by the static shift and can be used to remove the static shift to some extent. However, individual inversion of phase data yields highly nonunique results, and alone it will not work to correctly remove the static shift. Inversions of uncorrected magnetotelluric data yield erroneous and unreliable estimations, while static-shift-corrected magnetotelluric data provide better and reliable estimations of the resistivities and thicknesses of subsurface structures. In the present study, static shift (a frequencyindependent real constant) is also considered as one of the model parameters and is optimized together with other model parameters(resistivity and thickness) using the very fast simulated annealing global inversion technique. This implies that model parameters are determined simultaneously with the estimate of the static shift in the data. Synthetic and noisy data generated for a number of models are interpreted, to demonstrate the efficacy of the approach to yield reliable estimates of subsurface structures when the apparent resistivity data are affected by static shift. Individual inversions of static-shift-affected apparent resistivity data and phase data yield unreliable estimations of the model parameters. Furthermore, the estimated model parameters after individual data inversions do not show any systematic correlations with the amount of static shift in the data. The present study shows that only joint inversion of the apparent resistivity and phase data, without or with optimizing of the static shift, yields models that show good fits between the observed and the model data. Joint inversion results also reveal a systematic relationship between the estimated model parameters and the static shift in the data. The proposed approach also shows that estimated resistivities are ‘S’ (the static shift parameter) times the actual resistivities, and that estimated thicknesses are √S times the actual thicknesses without optimization of the static shift. This result is in good agreement with the existing relationship in the literature. Therefore, the global optimization procedure developed can be effectively used to optimize the static shifts in data, to obtain reliable estimations of model parameters. Subsequently, joint inversion of the apparent resistivity and phase data, with optimization of the static shift, is performed, which yields accurate estimates of subsurface structures. It is demonstrated that this approach can also be used when the data is not affected by the static shift. In such cases, the estimated static shift parameter ‘S’ will be close to unity. The efficacy of the approach is demonstrated with a field example from Singhbhum craton, eastern India, by providing an accurate estimation of the craton thickness and the conducting structure that lies below the craton

    NADI PARIKSHA: WRIST PULSE ANALYSIS WITH TRADITIONAL AND MODERN INTERPRETATION

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    Nadi Pariksha (Pulse diagnosis) is considered the most important assessment in Traditional Medicine System (TMS) for health monitoring. Traditional pulse analysis is subjective and hard to quantify. It is difficult for a Ayurvedic doctor to understand the pulse by his own perception due to its arbitrariness. To realize due recognition of TMS, standard techniques and standard instruments are urgently to be developed. In view of the increasing popularity of traditional and alternative medicine worldwide, researchers have explored pulse sensing and analysis, but due to the conflict of research goals, methodologies and statistical tools applied, the outcome of studies till date is not focused in one direction. This study explores current status of pulse signal interpretation by researchers using latest electronic signal processing techniques in recent years. The aim of research is towards development of pulse sensing and analyzing techniques using latest technology to assist or help Ayurvedic doctors, in a way to promote our countrys traditional pulse sensing. Since no sensor is benchmarked as a standard in wrist pulse sensing till date, various sensors were explored to sense wrist pulse and the results were correlated with the recent research. Optical sensor HOA 709 in reflective mode, exhibited best results, it captured the minute details and was used to acquire pulse signal of healthy subjects at Pita point on radial artery. The sensor was explored further to record pre-meal and post-meal data of two subjects and significant variation in signal contour was noticed. It can further be explored to extract more parameters with the help of Ayurvedic doctors to make it useful in health care.

    Prevalence and fungal profile of pulmonary aspergillosis in immunocompromised and immunocompetent patients of a tertiary care hospital

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    Background: Aspergillus is a fungus which may present an array of pulmonary manifestations, depending on the patient’s immunological and physiological state. Although the incidence of pulmonary aspergillosis occurs primarily in immunocompromised patients but the incidence is also rising in immunocompetent individuals, especially in developing countries. Aim: The objective of the study was to determine the prevalence and predisposing factors of pulmonary aspergillosis along with species identification. Materials and Methods: One hundred and three patients admitted to the Department of Chest and Tuberculosis and in the Department of Medicine from Jan 2012 to Jan 2013 were included in this study. The patients were epitomized on the basis of clinical signs and symptoms, physical examination, chest radiography, CT scans, histopathological examination, bronchoscopy and fungal examination including potassium hydroxide mount, fungal culture of sputum and bronchoalveolar lavage. Species identification was done by colony characteristics, slide culture and Lactophenol Cotton blue mount. Results: Out of the 103 patients, (63 males and 40 females) Aspergillus species has been isolated from 17 (16.5%) males and 07 (6.79%) females. Various predisposing factors of pulmonary aspergillosis have been identified in which pulmonary tuberculosis, chronic smoking and environmental exposure to asbestos, cement its tops the list. Many of the patients had multiple predisposing factors. Aspergillus species were isolated in 24 (23.3%) cases. Aspergillus fumigatus was the predominant species isolated in 13 (54.16%) cases followed by Aspergillus flavus in 07 (29.16%) cases, Aspergillus niger in 03 (12.5 %) and Aspergillus terrus in 1 (4.16%) cases. Conclusion: It is concluded that the prevalence of pulmonary Aspergillosis is quite high in immunocompromised individuals and low in immunocompetent individuals. An adequate and efficient evaluation of the etiological agents has a crucial role in the management of such patients

    Effects of different rates of nitrogen and pinching on yield and yield attributes of African marigold (Tagetes erecta L.)

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    Proper pinching practice and the optimum rate of nitrogen (N) enhance the production of marigold. An experiment was conducted at a farmer’s field in Gadawa-4, Gangaparaspur, Dang, Nepal from July 2018 to November 2018 to investigate the effects of different rates of nitrogen and pinching on yield and yield attributes of African marigold (cv. Kolkata Local). Two factorial experiment was laid in the Randomized Complete Block Design (RCBD) with three replications. There were eight treatments, consist of four rates of nitrogen (0, 50, 100 and 150 kg/ha) and two levels of pinching (pinching and non-pinching). The maximum plant height (89.70 cm), the diameter of flower (4.29 cm) and the fresh weight per flower (4.32 g) and early days to 50% flowering (61.58) were obtained at non- pinching. The highest number of flowers (60.66), yield per plant (237.49 g) and yield per hectare (9.89 t/ha) were obtained with pinching. The highest plant height (92.20 cm) was recorded at 150 kg/ha of N but the highest yield per plant (238.18 g) and yield per ha (9.91 t/ha) was obtained at 50 kg/ha of nitrogen application. No significant effect was noted on the days to 50% flowering, number of flowers per plant, fresh weight per flower and diameter of flowers by different rates of nitrogen. The interaction of pinching and different rates of nitrogen showed non- significant effect on yield per plant and yield per ha. But, the combination of pinching and nitrogen rates at 50 kg/ha recorded the maximum yield per plant (249.20 g) and yield per ha (10.36 t/ha). Hence it is suggested to use pinching practice with optimum application of nitrogen @ 50 kg/ha to obtain high yield of marigold

    Integrating Apparent Conductance in Resistivity Sounding to Constrain 2D Gravity Modeling for Subsurface Structure Associated with Uranium Mineralization across South Purulia Shear Zone, West Bengal, India

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    South Purulia Shear Zone (SPSZ) is an important area for the prospect of uranium mineralization and no detailed geophysical investigations have been carried out in this region. To delineate the subsurface structure in the present area, vertical electrical soundings using Schlumberger array and gravity survey were carried out along a profile perpendicular to the SPSZ. Apparent conductance in the subsurface revealed a possible connection from SPSZ to Raghunathpur. The gravity model reveals the presence of a northerly dipping low density zone (most likely the shear zone) extending up to Raghunathpur under a thin cover of granitic schist of Chotanagpur Granite Gneissic Complex (CGGC). The gravity model also depicts the depth of the zone of density low within this shear zone at ~400 m near Raghunathpur village and this zone truncates with a steep slope. Integration of resistivity and gravity study revealed two possible contact zones within this low density zone in the subsurface at depth of 40 m and 200 m. Our study reveals a good correlation with previous studies in Raghunathpur area characterized by medium to high hydro-uranium anomaly. Thus the conducting zone coinciding with the low gravity anomaly is inferred to be a possible uranium mineralized zone

    Technical risk assessment for the safe design of a man-rider chair lift system

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    Underground mining is a difficult area for miners to work. Miners must go to the working faces by walking, which is not only time consuming but also physically demanding. In mines, a man-rider chair lift system (MRCL) has been developed to alleviate the strain stresses caused by walking lengthy and uneven distances up to the working faces. All parameters, including horizontal and vertical distances, variation and inclination of underground mines, slope forces considering the weight of persons and chair, forces acting towards return and drive unit, curves angles, power to operate, and rope safety factor, are calculated mathematically while modelling a man-rider chair lift system for both the installation and extension phases. We analyzed the analytical approach in conjunction with practical installation of the man-rider chair lift system to establish if the installation and extension of MRCL is genuinely feasible in the current scenario. We also created a simulation model of steel wire rope in Creo 8.0 for analyzing the various stresses on it with the Ansys R 16.2 software. In both phase I and phase II, the factor of safety is above that recommended, and the system is a hundred percent reliable, risk-free, and safe for operation.The authors are grateful to FCT—Fundação para a CiĂȘncia e Tecnologia (Portugal)—who partially financially supported this work through the RD Units Project Scope: UIDP/04077/2020 and UIDB/04077/2020

    A comparative numerical analysis on the effect of welding consumables on the ballistic resistance of SMAW joints of armor steel

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    In the present investigation, a comparative study of ballistic impact behavior of Armox 500T (base metal) and its weldments prepared by low hydrogen ferrite (weldment-1) and austenitic stainless steel (weldment-2) consumables against 7.62 AP bullet has been performed with the help of finite element analysis code Abaqus 2017. Further, the result is validated with the experimental results. The experiment has been performed on the base metal, weldment-1, and weldment-2 against 7.62 AP bullet. Further, a two-dimensional explicit model has been developed for given purpose to simulate the bullet penetration at such high strain rate (103 s−1). Both bullet and plate are considered as deformable. Experimental results revealed that the depth of penetration in the base metal, weldment-1, and weldment-2 is 10.93, 13.65, and 15.20 mm respectively. Further computational results revealed that the depth of penetration of base metal, weldment-1, and weldment-2 is 10.11, 12.87, and 14.60 mm, respectively. Furthermore, weldment-1 shows more resistance against 7.62 AP bullet than weldment-2 in experimentation as well as FEA results. The percentage difference between experimental and FEA results are less than 10% which shows the prediction capability of FEA models. A feasibility analysis has been presented for using the welding consumables to weld the Armox 500T plate. Finally, in terms of ballistic resistance, the low hydrogen ferrite consumables are more appropriate than austenitic stainless-steel electrodes

    Assessment of dimensional stability, biodegradability, and fracture energy of bio composites reinforced with novel pine cone

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    In this investigation, biodegradable composites were fabricated with polycaprolactone (PCL) matrix reinforced with pine cone powder (15%, 30%, and 45% by weight) and compatibilized with graphite powder (0%, 5%, 10%, and 15% by weight) in polycaprolactone matrix by compression molding technique. The samples were prepared as per ASTM standard and tested for dimensional stability, biodegradability, and fracture energy with scanning electron micrographs. Water-absorption and thickness-swelling were performed to examine the dimensional stability and tests were performed at 23 °C and 50% humidity. Results revealed that the composites with 15 wt % of pine cone powder (PCP) have shown higher dimensional stability as compared to other composites. Bio-composites containing 15–45 wt % of PCP with low graphite content have shown higher disintegration rate than neat PCL. Fracture energy for crack initiation in bio-composites was increased by 68% with 30% PCP. Scanning electron microscopy (SEM) of the composites have shown evenly-distributed PCP particles throughout PCL-matrix at significantly high-degrees or quantities of reinforcing
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