National Institute of Technology Rourkela

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7542 research outputs found

Analytical and Numerical Solutions of Fractional Differential Equations

Differential equations are often used to explain the behaviours of real-life phenomena, and those are usually modelled by various differential equations with integer orders. Sometimes the behaviours of the physical problems may be advantageous to understand using non-integer order derivatives. In this regard, fractional calculus (FC) was introduced. Due to its hereditary and the description of memory properties, fractional-order models are more realistic and best suited in real phenomena than the integer-order models. The subject of fractional calculus has gained considerable popularity and importance during the past three decades mainly due to its validated applications in various fields. It deals with the differential and integral operators with non-integral powers. The fractional derivative has been used in various physical problems, such as frequency-dependent damping behaviour of structures, motion of a plate in a Newtonian fluid, controller for the control of dynamical systems, etc. The mathematical models in electromagnetics, rheology, viscoelasticity, electrochemistry, control theory, Brownian motion, signal and image processing, fluid dynamics, financial mathematics, and material science are well defined by fractional-order differential equations. D PI One of the most notable features of fractional derivatives is their distinctive nonlocal properties. This property allows to forecast the behaviours of phenomena by looking at their progress from the past to the present. Mostly used definitions of fractional calculus are Riemann-Liouville (RL) and Caputo fractional operators, defined by the convolution and the Power decay functions as kernel. Several researchers have extended the principles of fractional differential and integral operators to the fields related to various science and engineering problems using power-law distribution. However, when the fractional order is less than 1, this power-law distribution has no statistical significance. The fractional differential operators based on the power-law kernel meet certain classical conditions, such as index law, classical mechanical law, and singular kernels. It suggests that those operators based on the power-law kernel are physically weak and may not deal with more complex phenomena. Another problem is singularity which is challenging to explain in different natural phenomena. In order to address these problems, two important fractional derivatives, namely Caputo-Fabrizio and Atangana-Baleanu are developed. Although, these modern derivatives do not work under a power distribution, but they have nonsingular kernels. A generalized Mittag-Leffler function is used for Atangana–Baleanu derivative, and the Caputo-Fabrizio operator relies on the exponential law. Such operators have been able to model several scientific processes. Further, a new kind of operator was developed to represent two forms of fractional order, which reflect the fractional-order and the fractal dimension. The definitions of fractal-fractional differential and integral operators seem superior to the present fractional operators. One may obtain the fractal differential and integral operators when the fractional order is removed in the fractal-fractional differential and integral operators. Further, when the fractal dimension is neglected, then fractional derivatives and integrals are obtained. Hence, these fractal-fractional operators may catch more complexities than current operators as they have both exact and self-similar properties. Further, the uncertainties or randomness of the parameters and variables involved in the fractional systems are of serious concern. Investigations on a variety of fractional models are usually done by taking deterministic or crisp parameters, but the truth is quite diverse. The primary causes of the spread of uncertainty or randomness are defects in measurement, observations, environmental conditions, etc., which hinder the behaviour of models. As a matter of fact, these investigation anomalies indicate that the fractional models may not have the capability to demonstrate their normal behaviours. The influence of uncertainties becomes much more profound in the case of physical and structural problems due to the possibility of errors in the experiments or observations. In fact, several fractional physical and structural dynamics studies also support the claim of the possible inclusion of uncertainties in various parameters and initial conditions. In view of the above, the objective of this thesis has been to investigate a variety of fractional and fractal-fractional order models arise in i) wave dynamics, ii) fluid dynamics, iii) structural dynamics, iv) biology, v) economics, and vi) interpersonal relationship. In some of the problems, initial conditions and involved parameters are also considered as uncertain. Various computationally efficient analytical or numerical methods (where appropriate) are used/developed to investigate the models accordingly. Although a few methods have been developed by other researchers to analyse the above problems, but often those are problem dependent and are not efficient

Genesis of Gold Mineralization in the South Kolar and Gadag Greenstone Belts, Dharwar Craton: Constraints from Hydrothermal Alteration, Tourmaline Chemistry, Fluid Inclusion and Stable Isotope Studies

South Kolar greenstone belt (SKGB) in the Eastern Dharwar Craton (EDC) and Gadag greenstone belt (GGB) in the Western Dharwar Craton (WDC) are well known for Neoarchean orogenic gold deposits in India. Chigargunta (CG) and Bisanatham (BN) deposits with contrasting host rocks such as Champion gneiss and metabasalt respectively within the SKGB reflect almost similar steeply dipping structural attitudes (0–10/74W– 87E) that controls the emplacements of auriferous lodes. On the other hand, third generation deformations along the NW-SE were the key structural control for major gold mineralization in turbidite hosted Gadag gold field (GGF) in the GGB. Hydrothermal alteration mineral assemblages i.e., quartz + carbonate + muscovite + chlorite + sericite + tourmaline (± biotite) are common in both the SKGB and GGF deposits irrespective of their host rock compositions, deformation settings and P-T conditions of alteration. Although, mineralogically they are similar, alteration mineral chemistry and substantial mobility of elements during alteration of two contrasting lithounits from the CG (Champion gneiss) and BN (metabasalt) typically fingerprint the host rock chemistry. Abridged activity-activity [(aMg2+/aH+) vs. (aK+/aH+) and (aNa+/aH+) vs. (aK+/aH+)] diagrams corroborate the observed alteration-induced mineralogical changes, in accordance with the isocon plot and constrain the possible fluid composition. Occurrences of native gold in association with sulfides are more common in the SKGB while both invisible lattice bound refractory as well as native gold are observed in the GGF. Hydrothermally precipitated tourmalines intimately associated with/without sulfides, in the alteration zones, from the gold deposits of the CG, BN and GGF belong to dravite or oxy-dravite group. A significant fluctuation in chemical compositions (XFe, Mg, Ca) from proximal to inner zone and strong chemical zoning of tourmaline grains without changes in Na content reflect no changes in fluid salinity in the CG and suggest ore fluid evolution with multiple pulses in a cyclic fluid flow event. Such notable change in fluid chemistry is attributed to the result of fluctuation of fluid pressure during seismic fracture propagation accompanying gold mineralization event. The intra-deposit chemical fluctuation within tourmaline in the BN and GGF are insignificant. The low salinity and reduced nature of the ore fluid are consistent throughout all the deposits inferred from low to medium Na, medium to high X-site vacancy and low Fe3+/Fe2+ ratio. Detailed fluid inclusion study from the mineralized quartz-carbonate veins reveals low to medium saline (CG: 0.5–13.3 wt% NaCl equiv.; BN: 1. 6–6.4 wt% NaCl equiv; GGF: 0.04–9.6 wt% NaCl equiv.) H2O-NaCl-CO2±CH4±N2 primary fluid. Estimated P-T conditions (CG: 1.7–3.5 kbar/285–378 ℃; BN: 0.8–1.2 kbar/365405 ℃; GGF: 1.62.9 kbar/296333 ℃) by combining fluid inclusion, chlorite and arsenopyrite thermometry reflect greenschist facies conditions of alteration and mineralization at the SKGB and GGF. Alteration mineral assemblages, tourmaline chemistry and fluid inclusion study confirm that the low saline, reduced fluid transported gold as Au(HS)2 − complex and precipitated gold as a consequence of pressure drop induced phase separation as well as wall rock interaction processes rather than fluid mixing. Sulfur isotopic compositions of the ore fluid (34SH2S) (CG: –0.4 to +2.4‰, BN: +0.3 to +2.3‰ and GGF: +1.0 to +3.4‰) are indicative of average crustal sulfur source. The 34S (+1.5 to +4.5‰) values of mineralized sulfides overlap with host-rock early pyrites (–1.0 to +7.5‰) in the GGF. Thus, it can be inferred that the sulfur in the mineralizing fluid most likely have derived either by desulfidation and/or dissolution of early pyrites during the continuous fluid flux along the shear zone. Carbon (δ13CCO2) isotopic compositions of ore fluid deduced from δ13C of carbonates furnish a range from –2.4 to +3.3‰ in the CG, – 2.1 to +1.4‰ in the BN and –5.9 to +1.6‰ in the GGF. Such inferred narrow ranges signify that the carbonates in ore forming fluid could have possibly been derived by decarbonation or dissolution of marine carbonates during the metamorphic devolatilization of the greenstone belts. Hence, the metamorphic source of ore-forming fluid is postulated for the gold mineralization at the SKGB and GGF and it is comparable with other orogenic gold hosting greenstone belts in the Dharwar Craton and elsewhere in the world

Development of IoT-based Wireless Sensor System for Slope Stability Monitoring in Open-cast mines

Slope stability in open-cast mines is one of the dominant topics of geological interest. The slopes of open-cast mines need to be monitored consistently so that one has prior knowledge of any slope failure. An early-warning system is necessary for the open-cast mines so that loss of human lives and property is prevented. Both Internet of things (IoT) and wireless sensor system (WSS) have emerged as an aid for real-time monitoring systems. Using WSS, one can monitor the concrete environmental structures by sensing their changes whereas IoT communicates this sensed data from the real-time applications to the application for additional analysis. In real-time monitoring scenarios, power consumption and long-range coverage are of high concern. That is the reason, technologies like WSS, Long Range (LoRa), and IoT have to be collaboratively used to build a slope monitoring system. To monitor slope failure first, slope deformation has to be tracked so that a prediction can be made based on the pattern and generate an alarm that failure is to happen. A coaxial cable along with Time-domain reflectometry (TDR) is used to measure slope deformation based on the reflection principle. This TDR sensor with coaxial cable is set up in slope areas that are more susceptible to failure. Test through open-cast model experiment and shear testing experiment was performed with two types of coaxial cables calibrated with TDR – RG-6 and RG-213 out of which RG-6 was found to be most suitable. Both coaxial cable and TDR are present at the sensing end of the WSS. LoRa acts as a framework for IoT. Since mines are situated in extreme environmental conditions, it is not practical for the mine personnel to be physically present at the mine site to monitor the slopes. The existing slope monitoring systems do not provide the flexibility to monitor slopes independently. Slope monitoring is an exhaustive and risky task for the miners and mine officials if it has to be done physically since any time loss of life may happen due to slope failure. By incorporating LoRa, a wide area is covered and with WSS and IoT slope can be continuously monitored. LoRa operates on various SF out of which SF7 is chosen for this work. This is because, with the increase of SF value, the coverage distance also increases but the signal fades away. The field test results of LoRa with SF7 in open space or non-line of sight (NLoS) areas offered coverage of 2.3 km whereas in the mine site coverage of 1.7 km was obtained without any packet loss. This proved helpful for this research work in open-cast mines because the distance from the mine slope to the mine office is around 1 km. The data which comes from the real-time slope monitoring system has to be processed somewhere so that an early warning can be generated hinting at the occurrence of slope failure. For this purpose, fog computing comes into the picture. Instead of depending on the cloud for every computation, the sensed or monitored data is computed in fog and the outcome is provided to the user. Since the mine environment is uncertain, slope failure can happen within a fraction of a second. For such a scenario, latency-free processing, and delay-free data transmission is required which is offered by fog computing. Besides, it also brings the cloud functionalities nearer to the sensing layer which gives the user the flexibility and eases to use cloud services without any delay. With these motivations and aims, developed and implemented a novel real-time slope monitoring system in this research work is known as Fog-IoT Slope Monitoring (FIoTSM) system to monitor slopes and generate warnings of its failure

Polysaccharide-based Oil-in-water Emulsion Systems for the Prolonged Efficacy of Hydrophobic Antimicrobial Compounds

Prevalence of foodborne pathogens and its associated disease outbreaks are major causes of concern for public health globally. Significant efforts have been taken to resolve this issue, among which the use of antimicrobials is a major approach. Antimicrobial compounds have been used alone or in combinations to achieve enhanced functionality within food systems. Natural antimicrobials such as essential oils used in food preservation by conventional techniques are prone to rapid depletion owing to their volatile nature, hydrophobic properties, enzymatic hydrolysis, specific interactions with surrounding food components and alteration of flavor profile at higher usage levels. One strategy for prolonged protection of antimicrobial compounds is through designing a suitable carrier vehicle. In this study, the overall goal is to design oil-in-water emulsion systems for the sustained protection of various antimicrobial compounds against targeted foodborne pathogens. The first part of the work was carried out in model testing system such as Brain heart infusion (BHI) broth, where the effective concentration of antimicrobial emulsions prepared through ultrasonication and stabilized with gum arabic were evaluated. The oil phase of formulated emulsions was constituted with geraniol and carvacrol, incorporated at various ratios of 1:0, 2:1, 1:1, 1:2, and 0:1 (v/v). These emulsion systems were characterized for mean particle diameter, polydispersity index (PDI), ζ-potential, storage stability, creaming index, and microstructural parameters (confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM)). In addition, Time-kill assay for the formulated emulsions was tested against model bacterial pathogens, Gram-positive bacteria B. cereus MTCC 430 and Gram-negative bacteria Escherichia coli MTCC 443. The results demonstrated that among all the formulations, higher stability was displayed by combined oil, geraniol: carvacrol (1:1) emulsion with no visible separation of cream. Further, the microstructural analysis confirmed the presence of stable emulsion. Analysis of time-kill assay showed prolonged antibacterial efficacy for the combined essential oil-based emulsion against both the model bacterial pathogens. In the second part of the work, the antimicrobial emulsions incorporated with geraniol and carvacrol at the selected oil phase ratios were stabilized with Tween 80 and Gum arabic (coating solution). These emulsion-based coating solutions were used to extend the shelf life of goat meat. They were characterized for mean particle diameter, PDI, ζ-potential, storage stability and creaming index, and microstructural parameters. Evaluation of the antimicrobial activity of the functional emulsions was carried out against Gram-positive bacteria B. cereus MTCC 430 and Gram-negative bacteria Escherichia coli MTCC 443. The study showed that the emulsion-entrapped formulations could prolong the antimicrobial efficacy of geraniol and carvacrol till nine days as compared to treatments performed with non-emulsion formulations on a goat meat model. The final part of the work was focused towards using two volatile essential oils, d-limonene and trans-cinnamaldehyde stabilized by Tween-20 and Starch-Octenyl Succinic Anhydride (OSA), for the preparation and characterization of oil-in-water type emulsions (coating solution). The impact of this delivery system on the antimicrobial retention was studied against the model bacterial pathogens using fresh-cut papaya as the model food. It was found that the emulsion-based coating solutions could prolong the antimicrobial efficacy of d-limonene and trans-cinnamaldehyde against both B. cereus MTCC 430 and Escherichia coli MTCC 443 on fresh-cut papaya. Overall, the emulsion-based carrier systems demonstrated effective retention of antimicrobials in the model testing system (BHI broth) and a potential application of these delivery systems to extend the shelf-life of goat meat and fresh-cut fruits was identified

Impact of dietary modulations on the onset of Type 2 Diabetes in Drosophila melanogaster and its treatment mediated by metallic and polymeric nanoparticles

Diabetes mellitus is one of the most prevalent metabolic disorders of the current century. High calorie diet having high glycemic index (GI) are the major contributors of diabetes. Due to the complex nature of this disease, it is difficult to treat and often leads to huge treatment burden. Numerous studies have tried to understand the detailed mechanism of this disease to design new and effective therapeutic approaches. The application of nanotechnology in the field of diabetes have been proven beneficial. The current study aims to investigate the effect of dietary modulation in the onset of diabetes and established the role of anti-diabetic NPs by using Drosophila melanogaster as a model system. The first objective aims to investigate the effects of dietary advanced glycated end products (AGE). Oral feeding of three types of AGE compounds (i.e. AGE glucose, AGE-fructose and AGE-ribose) was found to alter growth and development of the flies. Beside this, the larva and adults showed persistent hyperglycemic condition, excess fat deposition and micronuclei formation in gut and fat body as well as insulin resistance. The flies also showed increased ROS formation via downregulation of the antioxidant enzyme system. Behavioral defects were also evidenced in the larval and adult locomotion, suggesting neuronal damage. The second objective depicts the role of Strontium ferrite, a metallic nanoparticle as a non-toxic anti-diabetic agent. Files fed with a high fat diet (HFD) were used as a diabetic model. The toxicity profile of the nanoparticles was checked, showing no DNA damage or cytotoxicity. Feeding of the NPs to the diabetic flies demonstrated that, the NPs were able to reduce fly weight, metabolic sugar and triglyceride level, reduce the deposition of fat and also reduce ROS level and behavioral abnormalities. In the third objective, the flies were reared on a high sugar diet (HSD), which tremendously affected their growth and development. Beside this, behavioral alterations was also seen. Hyperglycemia followed by excess fat deposition in the gut, fat body and crop confirmed the diabetic phenotype. A novel polymeric nanoparticle, namely polyvinylpyrollidone-curcumin (PVP-C) was checked for antidiabetic potential. Non-cytotoxic and non-genotoxic potential of the nanoparticles were evidenced from no DNA damage, and absence of trypan blue staining, as well as no phenotypic abnormality. Treatment of PVP-C NPs to the diabetic flies showed reduction of metabolic contents and ROS level. Together the study suggests the role of diet in diabetic onset and importance of nanoparticles having potential to be used alone as an anti-diabetic agent or a combination to deliver therapeutic molecules

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