7940 research outputs found
Sort by
Geodynamics of the Indo-Burmese Arc: Northwest Sunda Arc
No full textThe Indo-Burmese Arc (IBA) comprises highly populated regions of Northeast India, Bangladesh, and Myanmar. Thus, quantitative estimation of crustal deformation, earthquake occurrence process, and seismic vulnerability along this densely populated region is considered to be paramount. However, diverse opinion exists regarding the strain accumulation, status of active convergence, and associated seismic vulnerability across the IBA. In addition, the IBA is surrounded by several seismo-tectonically active geodynamic units such as Indo-Burmese Wedge (IBW) in the forearc, deformation front of Northeast Himalaya, Eastern Himalayan Syntaxis (EHS), Assam-Brahmaputra valley, Shillong Plateau, and laterally extruding Tibetan lithosphere in adjacent Sundaland block, etc. The geodynamic interaction and associated complexities of these regions and their interaction with the IBA remain elusive. Apart from these tectonic complexities, the second-largest seasonal hydrological load lies over the Southeast Asia covering the IBA plate boundary region. However, the exact interaction between the seasonally induced non-tectonic and tectonic deformation process along this plate boundary remains debated. In the present Ph.D. work, these tectonic and non-tectonic deformation aspects of the IBA have been characterized by constraining combined geodetic, seismic, and satellite based observations.
By constraining geodetic observations, the Euler rotation parameters of the Indian and Sunda plates are estimated. The India‐Sunda long-term relative plate motion (~37 mm/year) is distributed among three major active fault systems, namely, the Sagaing Fault (SF) (~18 mm/year), Churachandpur‐Mao Fault (CMF) (~17 mm/year), and the Blind megathrust (BMT) (~7 mm/year), from east to west across the IBA respectively. The estimated convergence across the BMT is significantly lower than the earlier estimates. Moreover, due to large scatter in the geodetic data close to the updip edge of the BMT, it is not certain whether the motion across the detachment is accommodated through shallow creep or in stick‐slip manner, thus leading to uncertainty in the seismic hazard in this densely populated region. Further, in the Northeast Himalaya, the lateral extrusion model of the Tibetan crust appears to contradict with the oblique convergence model of the Himalayan-Tibetan orogeny. Geodetic observations indicate that the overall India-southern Tibet convergence in the Northeast Himalaya (i.e., Bhutan and Arunachal Himalaya) is about 20–25% less than that in the neighboring central Himalaya and EHS. This deficiency of motion is accommodated through distributed deformation along the Dauki Fault and Naga Thrust, which suggests that these two units participate in the Northeast Himalayan strain budget via distributed deformation along the Assam-Brahmaputra valley. Thus, it has proposed that instead of partitioning in the backarc, the Northeast Himalaya has developed an active sliver along the Assam-Brahmaputra valley in the outer deformation front of Main Frontal Thrust in order to accommodate the deficiency in long-term plate convergence. It has argued that the strong eastward extrusion of Tibetan crust in the backarc is the main driving force for such unusual development of sliver in the outer deformation front. Further, by considering geodetic observations from Southeast Asia along with satellite data from Gravity Recovery and Climate Experiment (GRACE), the seasonal deformation over the IBA is characterized. In fact, the relationship between hydrological mass oscillation and seismicity modulation over the IBW and SF indicates no such prominent annual or semi-annual periodicity in the seismicity catalogue, which may be attributed to the higher magnitude completeness of the available seismicity catalogue (Mc>4.0). It appears that the IBA is a geodynamically and seismo-tectonically complex domain where both tectonic and non-tectonic deformation process operates
Multiple Fault Parameters Estimation of an Active Magnetic Bearing Integrated Coupled–Rotor–Bearing System
No full textCondition monitoring techniques have an important role in continuously running high-speed machines including jet engines, ship propellers, compressors, steam turbines and generators. Early detection and diagnosis of faults such as inherent unbalance, shaft bow/bent, misalignment, bearing, gear, rotor cracks and motor faults associated with these machines are the primary concern of researchers in the field. The excessive vibration generated at higher operating speeds due to these faults can be suppressed and controlled with the help of Active Magnetic Bearings (AMBs). AMB is a mechatronic product used in industries due to its excellent features such as no wear and tear, lubrication-free and frictionless operation due to the absence of mechanical loading. The present work mainly concentrates on the development of an identification algorithm to estimate fault parameters (inherent unbalance and misalignment) along with AMB parameters in an AMB integrated rotor-bearing-coupling system. First, an identification methodology is proposed to quantify fault parameters along with AMB characteristic parameters of a coupled turbine generator system. A simplest possible turbo-generator system is modelled to analyze coupling misalignment and inherent unbalance. Conventional methodology to estimate dynamic system parameters based on forced response information is not enough for an AMB-integrated rotor system because it requires additional current information along with displacement information. The controlling current of AMB is tuned and controlled with the help of a proportional–integral–derivative (PID) type controller. Lagrange’s equation is used to obtain equations of motion (EOMs). Accordingly, a SIMULINKTM model is developed and solved using Runge–Kutta technique to acquire the time domain responses (current and displacement). The fast Fourier transformation (FFT) is applied on obtained responses to acquire responses in frequency domain. A methodology based on the least-squares regression approach is proposed to evaluate the multi-fault parameters of AMB integrated rotor system. The robustness of the algorithm is checked against various levels of noise and modelling error and observed efficient. An appreciable reduction in misalignment forces and moments is observed by using AMBs. Next, a finite element method (FEM) is implemented on the proposed model to overcome the limitations of the numerical model. The purpose of the FEM model is to represent the complex physical system more accurately. A quantification technique is suggested to evaluate the tuned AMB characteristics along with imbalance and coupling misalignment dynamic parameters. A FEM modelling with a high-frequency reduction scheme is utilized to acquire reduced system equations of motion. The advantage of employing a condensation scheme is twofold; first, it reduces the number of sensors required and second, only linear (practically measurable) degrees of freedom present in equations of motion. A SIMULINKTM code is prepared to solve a reduced linear differential equation. The time series signals (current and displacement) obtained are transformed into a frequency series utilizing Fast Fourier Transformation (FFT) and utilized in proposed algorithm. To establish the accuracy and effectiveness of the methodology, the estimated parameters are evaluated under two different frequency bands against measurement noise and modelling error (5% variation in mass of the disc and bearing characteristic parameters). The proposed FEM model is then extended to estimate the speed-dependent fault and AMB characteristic parameters along with speed independent unbalance parameters. Here, a novel gyroscopic high-frequency condensation (GHFC) scheme is proposed to obtain reduced EOMs for the system. The transformation matrix obtained in standard high-frequency condensation (SHFC) is modified by adding a gyroscopic effect into the transformation matrix to achieve the novel GHFC. The estimated parameters are compared for SHFC and GHFC. The GHFC is found effective over SHFC techniques. The effect of noisy response and modelling error on the estimation algorithm is analyzed and found competent. The work carried out in this thesis mainly focuses on the modelling, analysis and estimation of fault parameters of an AMB integrated coupled rotor-bearing system. AMB is used as an agent to suppress the excessive vibration generated due to various faults present in the system. The faults considered in this analysis are coupling misalignment and inherent unbalance. The identification methodology developed has scope in the online condition monitoring of rotating machines
Response of local weather to urban induced land-use change: A study over eastern and southern Indian cities
No full textUrban transition is an unstoppable process in developing countries. Despite the planning measures, the growing cities face the impact of urbanisation in the form of severe LU alteration. Though land use and land cover (LULC) change process, during urbanization, is relatively localised, it has regional and global impacts. Urban induced LULC change affects land-atmospheric interactions due to changes in surface energy budget and anthropogenic activities. Urbanisation process can severely affect the diurnal temperature, circulation pattern and spatial-temporal rainfall distribution over a city. Therefore, the main objectives of the thesis includes both observational and numerical modelling techniques for quantifying the urban sprawl and dynamics, analyzing the longterm urban climatology and examining the role of urban induced LU change during extreme weather events like heatwaves, thunderstorms and urban floods. Urban dynamics of cities using satellite data and ‘spatial metrics” based indices are analysed to quantify the urban LU increase in different cities. Observational data is used to understand the effect of urban growth on long-term climatology. For both urban growth, dynamics and climatological analyses, the Tier-I cities like Chennai, Bengaluru, Hyderabad and Kolkata and the Tier-II cities like Bhubaneswar-Cuttack, Ranchi, Visakhapatnam and Coimbatore are considered. Multiple numerical simulation-based experiments were carried out considering the mentioned weather events over some of these cities. The urban induced LU change impact is examined using different types of LULC data in the weather research and forecasting (WRF) model with varying urban fractions. The concerned cities of this study experienced a massive load of population inflow, industrialisation, and economic development. Since all these cities have the potential to grow as a future megacity, there is an urge to assess the current scenario of urban sprawl dynamics for careful design of the city and policymaking. Tier-I cities like Chennai and Hyderabad experience spreading of the city core, but Kolkata and Bengaluru mostly show infill growth. These cities show compact development up to ~25–35km radius and mushrooming of satellite townships towards the periphery is seen. Ribbon developments along the expressways are found connecting to the nearby small towns. Among the tier- II cities, Visakhapatnam develops a secondary core and expanding rapidly than the central core, while Ranchi shows the highest degree of sprawling. Fanning and fringe development are predominant for Coimbatore city. Both Cuttack and Bhubaneswar are approaching towards each other to form a single metropolitan. The analysis suggests the growth of the cities expanding its boundary irrespective of their geographical location and type. Climatological analysis suggests both increase and decrease of the diurnal temperature range (DTR) over different cities. The decrease and increase in DTR are due to the increase in minimum temperature and overall general warming due to global warming respectively. An overall increase in rainfall and lighting activity is seen for pre and post-monsoon days indicating the enhancement of convective processes over cities. Urban induced LU change incorporated in the model using updated ISRO LU. The impact of LU change is examined by analyzing the outputs from updated ISRO and older USGS LU based simulations. During HW episodes, the analysis revealed that the Tmax is hardly affected due to the LU change while most prominent increment in Tmin is seen. The increment in Tmin contributed to the decrease in DTR, causing maximum discomfort for city dwellers during the HW episode. Computed urban heat island (UHI) shows higher values for updated LU considerations indicating the feedback from larger impervious areas. For all the simulated cases, higher UHI variation found over industrial cities followed by near coastal cities similarly the LU change simulation is mostly noticed over the industrial city, while moderate and least effect seen for near-coastal ones. Comparative analysis has confirmed that UHI development is highly localised and unique to each city, while the amplitude of UHI is related to the type of the city whether industry dominated or not. The UHI correlation to the size of the city did not hold good for our case because of the geographical location and influence of large water body inside the city. Experiments for thunderstorms (TS) using recent LU based simulations predict most of the rainfall inside the city boundary towards the northern and southern part of the Bhubaneswar-Cuttack urban-complex with significant improvements in the amount. Major amount of rainfall is found to be distributed in the downwind direction being influenced by the southwesterly circulation. The simulations confirm that the urban area does play an important role in the spatial distribution and temporal variation of precipitation in the current scenario. For the case of Kolkata metropolitan, model results reveal a higher precipitation distribution over high-density urban areas. Results for the impacts during urban flooding event over Chennai were found to be sensitive to urban growth incorporated in different LU data sets for prediction of rainfall and surface runoff. The most significant impact was noted with updated urban LU. Urban induced LU change played an important role in redistributing the rainfall and the convection build-up. Higher runoff is simulated by the experiments with a high fraction of urban LU than the low urban LU, which inhibits the percolation process and enhances more surface flow of runoff water. The flood scenario was due to the enhanced runoff as a consequence of the increased urban built-ups and impervious layers in the metropolitan area. Though the large scale systems caused the extreme rainfall event prevailed over the Bay of Bengal, the role of urban impervious layers in enhancing the surface runoff and thereby causing the flood scenario cannot be denied. The impressions of updated urban LU is apparent in simulating the weather events like HW, TS and extreme rainfall causing urban flood and must be accounted for in emerging urban modelling systems
Electrocardiogram Signal Analysis for Myocardial Infarction Detection and Reconstruction
No full textRecent advances in biomedical signal processing have resulted in the development of many reliable medical diagnosis systems that can facilitate in providing better health-care to patients. These are accomplished with advanced techniques for accurate detection, correct classification and fast localization of disease, and efficient reconstruction of biomedical signal. Out of all the biomedical signals, electrocardiogram (ECG) is the most suitable modality for early identification of many cardiovascular diseases, as it is the easy and non-invasive way of assessment of cardiac condition. ECG signal results from the electrical activity of the myocardium cells which leads to contraction and relaxation of the heart muscles alternately in atria and ventricles. Myocardial infarction (MI) is one of the most common reason behind the mortality of human beings worldwide. Timely detection of MI in ECG signal is one of the important task in cardiac health monitoring system, which has immense importance in clinical diagnosis. On the onset of MI three basic changes are generally noticed in the leads facing the infarcted wall. ECG signals are affected by lots of noises like muscle artifact (MA), baseline wander (BW), power line interference (PLI) and white Gaussian noise (WGN). Hence tracking of all the morphological alterations in ECG recordings due to MI as well as original ECG signal reconstruction have pivotal importance in healthcare monitoring system. In this thesis, we aim to devise efficient methodologies for accurate detection of MI in ECG signal and reconstruction of the same. Fourier transform (FT) represents a signal as a summation of sinusoids and it depicts the signal in frequency domain only as there is no localization in time. Wavelet transform (WT) is an effective tool for analysis of signals with both temporal and frequency resolution levels. It overcomes the fixed window length problem of short-time Fourier transform (STFT) because of its scaling and translating parameters. Discrete WT (DWT) represents the correlation of the signal with the scaled and translated versions of the mother wavelet. The multiresolution properties of WT are explored for the extraction of the fiducial points in the ECG signal. Hence in this thesis, we have utilized wavelet transform to identify the locations affected due to abrupt changes caused by onset of MI in the frequency domain at a particular instant of time. In particular, multiscale energy analysis is carried out on the subbands resulted from WT and then using the distinct multi scale multi energy features and threshold based classification rule, the detection of MI has been performed in the ECG recordings. We have also made an attempt for the selection of suitable wavelet basis functions for detection of MI. The above proposition has limitation of providing phase information of the ECG signal. In order to overcome this bottleneck, we have employed Stockwell transform (ST) to ECG signal that provides better time resolution in high frequency and better frequency resolution in low frequency. ST uses concept of dynamic window length and also preserves the phase information of the ECG signal during signal decomposition. The phase distribution pattern as a result of MI are explored for detection of MI and to get advanced control over both time and frequency resolution, modified ST (MST) is employed for signal decomposition. The efficacy of the above proposed detection methodologies is validated using both MI and healthy ECG data. This dissertation also aims for devising reconstruction methods of ECG signal while applying to advanced cardiac health monitoring system. Interacting multiple model (IMM) has the adaptability of interchanging between several morphological representations. It offers the advantage of not necessitating user-specific parameters. This model does not necessitate a priori information about the ECG signal to initialize the filter parameters and delimitation of fiducial points of ECG signal. The particle filter (PF)-based schemes show superiority owing to their freedom from a single assumption on the signal model and noise model. Besides, it has the potential of simultaneously tracking multiple pathological and morphological changes in ECG signals due to MI. Thus, the parameters of the model are estimated by adopting the PF, so that the MI affected ECG signals can be efficiently tracked. Investigations on ECG signals signify that the IMM PF scheme can represent several MI morphologies with minimum prior information without distorting the helpful diagnostic information of ECG accurately. Better time and frequency localization ability of sparse representation approach is leveraged for efficient ECG signal reconstruction by presenting a new ECG signal reconstruction technique for efficient tracking of ECG signal in different noise driven situations. A new ECG reconstruction technique which combines IMM scheme with context aware learning based sparse representation is proposed. We adopted KSVD algorithm for dictionary learning for sparse representation of the noisy ECG signals. Different dictionaries are used to recover the ECG signals in different noise driven environments. The objective is to show the efficacy of the proposed learning based approach in tracking the multiple pathological and morphological changes occurring in ECG signals without distorting the helpful diagnostic information of ECG for better reconstruction in different noisy environments. All the proposed methods are validated with ECG data taken from PTB diagnostic ECG database and MIT-BIH arrhythmia database. Performance evaluations of these methods are compared with their related state-of-the-art methods both qualitatively and quantitatively
Optimization and Prioritization of Test Scenarios for Object Oriented Systems using Soft Computing Techniques
No full textThere are three major verticals of software testing, i.e. test case generation, optimization and prioritization. At first, test cases are generated aiming at achieving maximum coverage. Then, test case optimization and prioritization are done on the generated test cases to minimize various factors like effort, cost etc. So, our work is concentrated on test suite management through generation, optimization, and prioritization of test scenarios. In our first work, an approach is proposed to optimize the test scenarios while keeping the percentage of coverage intact using Intelligent Optimization Agent (IOA). First, the System Under Test (SUT) is modelled using UML Activity Diagram which is then converted into an Activity Graph (AG). The graph is traversed and the optimized test cases are found out by using IOA. Further to make the optimized test suite more effective, a duplicate/redundancy node removal algorithm is proposed to remove the redundant nodes in optimized test scenarios. Then, the approach is extended by combining UML activity diagram with the sequence diagram. Addition of sequence diagram has increased the efficiency by detecting more faults like message dependency faults etc. Both the proposed approaches are compared with different existing approaches and found to be very effective i.e. the number of optimized test scenarios (37 for HMS case study) is better than other approaches. Our next work is proposing an approach for test scenario optimization using UML behavioural diagrams and cuckoo search algorithm. The system under test is modelled using the UML activity diagram and sequence diagram. An intermediate graph i.e. Activity Sequence Graph (ASG) is generated by considering the features of both the diagrams. Then, the cuckoo search algorithm is applied to optimize the test scenarios. The proposed work is also compared with some existing work and the number of optimized test scenarios (16 for HMS case study) is better than other approaches. Next, an approach is proposed for test scenario prioritization using UML behavioural diagrams and association rule mining. To improve the fault detection rate, an approach is proposed for prioritizing the test scenarios by using multiple modified functions and association rule mining. Here, UML activity diagram and sequence diagram are used to model the system and Activity Sequence Graph (ASG) is generated taking into account the combined features of both the diagrams. Then, test scenarios are generated by traversing the graph. The affected nodes and corresponding modified nodes are found out using a forward slicing algorithm. Then, Association Rule Mining (ARM) is applied to the historical data to generate the frequent pattern. Finally, test scenarios are prioritized based on Business Criticality Test Value (BCTV) and frequent pattern. The APFD metric is used to verify the effectiveness of proposed approach. The APFD value of our approach is 0.8258 (for HMS case study) and found to be better than other approach
Genome-wide Identification and Characterization of Features of the Piwi- Interacting RNAs and Targets
No full textSmall non-coding RNAs (sncRNAs) are presently being recognized as an essential player in the modulation of regulatory events and implicated in the etiology of human diseases. In the present study, we comprehensively decoded the presence of Piwi-interacting RNAs (piRNAs), a recently discovered class of sncRNAs in the normal human ovary (NO) and its cancer subtypes: endometrioid ovarian cancer (ENOCa) and serous ovarian cancer (SOCa), along with their characteristic features encoded within sequence and structures as well as target binding features. In this regard, we performed next-generation sequencing (NGS) followed by comprehensive bioinformatics analysis and identified a catalog of 219, 256, and 234 piRNAs in NO, ENOCa, and SOCa samples, respectively. Furthermore, our study revealed some key piRNAs, piR-52207 and piR-33733 involved in the modulation of the pathophysiology of ovarian carcinoma. Moreover, we have identified several sequence and structural features of piRNAs, including its precursors and piRNA target sites, that might aid in the proper identification of piRNAs and their targets, which is essential for decrypting piRNA biogenesis and functions. In summary, the present study decodes piRNA-mediated target regulation in the pathophysiology of ovarian cancer subtypes and distinct sequence and structural features of piRNAs and their target sites providing a complete picture of the piRNAs and piRNA-mediated regulations. This might pave the way for developing tools for predicting piRNAs and their targets more precisely
Facile Synthesis and Photocatalytic Application of Bi-Based Binary/Ternary Heterostructure Nanomaterials Towards Degradation of Emerging Pharmaceutical and Agrochemical Contaminants
No full textIn this thesis, the fabrication and photocatalytic application of bismuth based novel binary/ternary heterostructure materials has been described for mineralization of selected pesticides and emerging pharmaceutical contaminants. Initially, morphology controlled synthesis of Bi2O2CO3 was performed by using a modified hydrothermal route. The Bi2O2CO3 was subsequently used as a precursor for synthesis of phase pure tetragonal -Bi2O3 material. The Bi2O2CO3 and -Bi2O3 had been used as base materials for construction of visible light active binary/ternary heterostructure photocatalysts. In a novel approach, facile one pot synthesis routes were also developed for fabrication of CdS/BiOBr/Bi2O2CO3 and Bi2S3/β-Bi2O3/ZnIn2S4 ternary heterostructure materials with improved charge carrier separation and enhanced photocatalytic activity.
Bi2O2CO3 nanoplates with high aspect ratio and hierarchical nanostructures were prepared by a hydrothermal technique using urea/hexamethylenetetraamine as hydrolysing agent and KCl/KBr as additive in different solvent systems. The relative molar proportion of urea and KCl was crucial for phase purity as well as thickness and planar dimension of the BSC plates. The BSC nanoplates were used as substrates to prepare CuS/Bi2O2CO3 binary heterojunction systems. The presence of crystalline tetragonal BSC and hexagonal covellite CuS phase was inferred from XRD study. Morphologically, the CuS/BSC material contained CuS nanorods and BSC nanoplates. An HRTEM study suggested microscopic close contact between the CuS nanorods and BSC nanoplates. A study of optical properties revealed improvement in visible light absorption and enhanced separation of excitons. The CuS/BSC materials were used as photocatalyst for chlorpyrifos (CP) pesticide degradation under visible light irradiation. The heterojunction materials were highly active achieving >90% degradation within 3 h of reaction. The degradation pathway of CP and photocatalytic mechanism was studied in detail by using radical trapping experiments and analysis of intermediate products by GC-Ms analysis. In order to further explore the potential of Bi2O2CO3 based semiconductor heterostructure towards pesticide degradation, binary BiOBr/Bi2O2CO3 material was prepared by optimizing the molar ratio of Bi(NO3)3.5H2O precursor salt, urea and KBr using same hydrothermal protocol. In addition, a one-step hydrothermal method was developed for morphology controlled synthesis of CdS/BiOBr/Bi2O2CO3 ternary heterostructure materials. The ternary system contained well dispersed CdS nanoparticles (50-80 nm) anchored over ultrathin BiOBr and Bi2O2CO3 nanoplates with high interfacial contact. A significant enhancement in visible light absorption, prolonged life time decay and improved charge carrier separation and migration property accounted for the excellent photocatalytic activity of the ternary heterostructure towards atrazine herbicide degradation in a short span of time (>95% in 30 min). An MTT assay study revealed that the photo-catalytically treated atrazine solution showed significant reduction in cytotoxicity.
The Bi2O2CO3 was used further as a precursor to prepare metastable -Bi2O3 by using a low temperature calcination route. The -Bi2O3 was subsequently modified with metal chalcogenide (NiS, Bi2S3, and ZnIn2S4) to prepare binary/ternary heterostructure systems. The visible light driven photocatalytic activity of the heterostructure materials was explored for photodegradation of pharmaceutical contaminants from aqueous sources. Initially, a facile method was also developed for synthesis of ultrathin α-NiS nanosheets under mild conditions using hexamethylenetetramine as hydrolyzing agent and Na2S2O3 as sulfur source. The α-NiS nanosheets were subsequently hybridized with -Bi2O3 to prepare a series of α-NiS/-Bi2O3 composite nanomaterials. The α-NiS/-Bi2O3 composite materials were thoroughly characterized using a variety of techniques to understand their structural, optical, electrochemical, microstructural and morphological attributes. The α-NiS/-Bi2O3 materials exhibited improved visible light absorption, enhanced charge carrier separation and photo-electrochemical properties. The microscopic close contact between the two semiconductor phases was established from the morphological studies. The α-NiS/-Bi2O3 ¬system was highly active for tramadol degradation from aqueous solution achieving 94% degradation in 3 h. The effect of various reaction parameters and the photocatalytic mechanism was investigated thoroughly. The photocatalytic potential of -Bi2O3 based heterostructure materials was further explored by rational design of a Bi2S3/β-Bi2O3/ZnIn2S4 ternary heterostructure for degradation of tetracycline antibiotic and microbial disinfection. The co-assembly of Bi2S3 and ZnIn2S4 with β-Bi2O3 was achieved by a tailor made in situ reflux route using thioacetamide as sulfur source. Comprehensive characterization of the ternary composite revealed close microscopic contact between the semiconductors, fast electron channelization, enhanced charge carrier separation and a prolonged life time (11.25 ns) of the excited state. The ternary composite exhibits excellent visible light assisted photocatalytic activity for aqueous phase tetracycline (TCN) degradation achieving 96.3% (kapp= 0.0868 min-1) degradation in a short reaction span of 40 min. A bacterial inactivation study conducted using Enterobacter cloacae suggested good visible light assisted bacterial degradation activity of the coupled semiconductor system. MTT assay study confirmed the non-cytotoxic nature of the treated TCN solutions. Finally, the occurrence of Z-scheme electron transfer mechanism in the above mentioned binary/ternary heterojunction was deduced from radical trapping experiments and ESR study which accounted for the excellent photocatalytic activity of the ternary composite material
Design and Analysis of Mutual Authentication Scheme in Multiserver Environment
No full textThe advancement of network technology has changed the world’s perspective toward the Internet. The growth of the Internet and telecommunication technology has facilitated several remote access to the server while being located anywhere. Remote access is essential for providing various Internet services like telecommuting, banking, gaming, shopping, etc. However, the protection of user credentials’ privacy and the provision of several remote services using an insecure channel is a critical issue. Thus, mutual authentication and session key security are the vital characteristics of a remote access security policy. Mutual authentication is a user-friendly and scalable mechanism to establish secure and authorized communication between the remote entities over the insecure network. This dissertation focuses on the design and analysis of the variants of user authentication schemes along with their applications. The authentication schemes based on smart card and biometric have been suggested for the multi-server environment, cloud environment, and fog environment. The first contribution presents a new smart card-based authentication scheme for the multi-server environment (SMASME). The proposed scheme maintains a low computational and communicational cost as it uses only exclusive-or (XOR) and hash function. Besides, SMASME ensures better security and efficiency as compared to other existing approaches. In the second contribution, a biometric-based authentication scheme (BMASME) is suggested for a multi-server environment using Elliptic Curve Cryptography (ECC) to resolve the smart card-based issues. The scheme achieves user anonymity, session key security, and several security features during communication. Nowadays, the cloud is becoming an important paradigm due to cost efficiency, scalability, availability, and high resource utilization. Thus, the authentication scheme for the cloud server environment is more challenging and has become an active area of research. The third contribution hence proposes a biometric-based authentication scheme referred to as (BMASCE) for healthcare applications in the cloud environment. Since the patient’s information is sensitive and must not be revealed to others except the healthcare professionals, the protection of patients’ privacy has become another key issue for health care applications. Thus, mutual authentication with anonymity property is the most basic and commonly used method to resolve security and privacy issues. The BMASCE has low computation cost, computational cost, and several security features compared to other existing schemes. In the final contribution, an efficient ECC based authentication scheme called (BMASFE) is designed to resolve the cloud server issues. This study also focuses on the development of Intra fog and Inter fog communication for latency reduction. The comparison among BMASFE and other related existing user authentication schemes in
the context of security functionality, communication, and computation costs show that the scheme is efficient. The mutual authentication of the proposed schemes is proved with the help of Burrows-Abadi-Needham (BAN) logic. In addition, the session key security is proved under Real-or-Random (RoR) model. The informal security analysis of the proposed schemes proves that the scheme is secure against possible other known attacks. Furthermore, the formal verification of the proposed schemes is simulated using a widely accepted and powerful AVISPA tool, which confirms the schemes are safe and secure
Development and Evaluation of Bituminous Mixes Containing Reclaimed Asphalt Pavement and Recycled Concrete Aggregate
No full textDue to increased maintenance and rehabilitation activities related to bituminous pavements, huge quantity of aged bituminous mix is generated as waste, needing huge space for disposal/dumping. This waste is commonly referred to as reclaimed asphalt pavement (RAP). The RAP material normally contains substantial amounts of aggregates and bitumen. The latter is found to have lost most of its desirable properties in course of its service. It is also of great concern that, due to unabated construction activities, aggregates used in bulk in road paving layers become scarce and costlier because of the fast depleting natural stone resources. Keeping these two issues in mind, a good number of attempts have been made to re-use these pavement wastes, thus reducing the cost of construction as well as preserving the available natural stone resources. Concrete is a commonly used material for buildings and also for different types of structures. The demolition of such concrete structures because of end of their service life or any other reason, results in huge amount of construction and demolition waste. The disposal of such concrete demolition wastes requires huge space for dumping. When these concrete wastes are recycled and turned into aggregates for new construction works, these are known as recycled concrete aggregate (RCA). Similarly, plastics which are used in day-to-day activities remain as wastes once they are used. These plastic wastes being non-biodegradable adversely affect the environment.
It is reported that, both RAP and RCA have been separately used in bituminous pavements with promising results. But a study on the combined effect of RAP and RCA in bituminous paving applications has not been done systematically. The scholar has therefore been motivated to use RAP and RCA each collected and processed locally for development of new bituminous paving mix through a simple and innovative approach. The approach involves recovering bitumen from the RAP and addition of fresh bitumen suitably to the extracted bitumen (from RAP) in order to achieve the desired conventional and rheological properties of the target bitumen conventionally used in India, so that RAP may be reused as new bituminous paving mix. Though many researchers have used different rejuvenators to modify the aged binder characteristics, the present study involves the use of low viscosity VG10 and VG30 bitumens each in appropriate proportion for achieving the normal binder consistency as that of target VG40 bitumen. Further, it was felt necessary to develop and evaluate the resulting dense bituminous macadam (DBM) mixes containing mainly RAP and additional ingredients such as aggregate and virgin bitumen of low viscosity, with all ingredients in selected proportions. A new general approach was developed to determine the quantity of fresh aggregates and virgin low viscosity bitumen to be added to RAP to suit the existing aggregate grading of RAP, RAP bitumen content and the selected proportion in modified bitumen blend. The tests used for evaluation included Marshall characteristics, indirect tensile strength, moisture susceptibility, fatigue life and rutting resistance. For the purpose of comparison a control mix having same aggregate grading, made of conventional stone aggregate (CSA) and VG40 bitumen was also considered. Further, attempts have been made to replace the conventional coarse aggregate fractions in modified RAP mixes by RCA and pretreated recycled concrete aggregate (PRCA). As a part of further development, waste plastic in the form of low density polyethylene packaging for milk (500 ml pouches) available locally and abundantly, were utilised to further modify the resulting paving mixes.
Based on penetration tests initially corroborated by other conventional and rheological tests, the optimum proportions of the modified blend comprising VG10 or VG30 bitumen and RAP bitumen were found to be 60:40 and 70:30 respectively. As compared with virgin bitumen, the modified bitumen binder also resulted in improved resistance to rutting at high service temperatures, and better resistance to fatigue against the RAP bitumen at intermediate performance temperatures. Marshall characteristics and moisture susceptibility parameters indicated that 30% RAP for VG30 and 40% RAP for VG10 can be considered as optimum dosages for the modified RAP mixes (containing additional CSA, RCA or PRCA), which can perform either similar or better than the control mix (CSA-VG40). Modified RAP mixes prepared with RCA/PRCA and waste plastic (designated respectively as RAP-RCAP/ RAP-PRCAP) were observed to have better Marshall characteristics than the control mix, especially in terms of Marshall stability and flow value. Utilisation of waste plastic in modified RAP mixes can be less susceptible to moisture induced damage. Use of pre-treated RCA and RAP in the bituminous mix was found to be effective with decreased rut depth and higher flow number in contrast with the control mix. Utilisation of waste plastic in all categories of modified RAP mixes considered in the study further enhances the rutting resistance as determined in terms of flow number and rut depth. The modified RAP mixes with pretreated RCA and waste plastic (RAP-PRCAP) were also observed to have significant improvement in terms of resilient modulus as well as fatigue life than the control mix at all test temperatures. This indicates a major benefit of using RAP, pre-treated RCA and waste plastic in the resulting bituminous paving mixes. Besides, the modified RAP mixes prepared with pre-treated RCA and waste plastic in dense bituminous macadam (DBM) layer of flexible pavement can reduce the total cost of the pavement (up to 15%, for a service period of 30 years) as compared with conventional bituminous mix (control mix).
On the whole, this study recommends 30%RAP-PRCAP-VG30 and 40%RAP-PRCAP-VG10 mixes (each with 8% plastic by weight of respective optimum bitumen content) have much superior performance characteristics than the control DBM mix with conventional stone aggregate and VG40 bitumen. It is concluded that, this combination of waste materials such as RAP, RCA and waste plastic can be reutilised in place of control bituminous paving mixes with improved performance characteristics, which can lead to sustainable bituminous paving ensuring economy, conservation of natural resources and reduction of environmental concerns. The utilisation of RAP and RCA modified with waste plastic in a fresh bituminous paving mix, is a new and original contribution of the present study
Agro Hydrological Characterization of River Basin in Tropical Monsoon Climatology under Changing Land Use and Climate Scenarios
No full textThe present study assessed the impact of climate and land use change on agro-hydrological characteristics in the Anandapur catchment of Baitarani River basin, India using the Soil and Water Assessment Tool (SWAT) hydrological model. SWAT is a physically based semi-distributed hydrologic model and widely used for hydrological fluxes simulation and watershed management across the globe. The future climatic alterations under two Representative Concentration Pathways (RCPs 4.5 and 8.5) scenarios are quantified by an ensemble of two different CMIP5 models (CNRM-CM5.0 and GFDL-CM3.0). The future climatic alterations under two Representative Concentration Pathways (RCPs), i.e., 4.5 and 8.5 scenarios are quantified by an ensemble of two different CMIP5 models, i.e., CNRM-CM5.0, GFDL-CM3.0. The outcomes of this study reveal that the future rainfall and temperature may experience an increasing trend with gradual shifting of monsoon from mid-June to mid-May. The climate change impact on the considered three hydrological fluxes indicates that the streamflow and evapotranspiration (ET) exhibit significant increasing trend across all the future projections, whereas the groundwater recharge (GWR) is expected to have a comparatively slower increasing trend. The spatial discretization of streamflow and ET exhibits a linear association with the precipitation during the base period and future climate scenarios. The reduction in the GWR could be attributed to the increased urbanization and decreased forest cover in the coming time scales resulting in three major sub-basins to have only 0-20% increase with respect to the base period. The future LULC change scenarios are simulated using land change modeler (LCM). A land change modeler is a decision-making tool and it is facilitated with LULC change analysis, modeling, identification of transitions between LULC classes, and predict the future scenarios of the landscape by incorporating user-specified drivers of changes. The LCM uses Markov Chain model to compute the future land-use change of each land cover class for a specified date. The model is calibrated and validated at the catchment and sub-catchment level with an uncertainty analysis. After validation of model the future LULC change scenarios are predicted by the model in 2030 and 2040 using the transition matrix. Then combined effect of climate and land use change on hydrological components has been analysed onsidering both climatic and land use dataset. The variation of different hydrological components based on combined effect of both climate and land use change scenario are almost similar to variation found in the climate change only scenario. The crop yield is simulated in spatial and temporal scale considering different irrigation strategy. The performance of the model is found to be satisfactory for crop yield simulation during the calibration and validation periods. The optimal irrigation schedule could save more water leading to less groundwater exploitation, increase yield at par with full irrigation and higher crop water productivity (CWP) than other irrigation scenarios. The drought have been evaluated based on climate and land use change scenarion using different drought indices. The variation of standardized precipitation evapotranspiration index (SPI) and standardized precipitation evapotranspiration index (SPEI) are almost similar in annual time scale. Under moderate and severe conditions the number of drought events has increased based on SPEI compared to SPI. The number of drought months under moderate and severe conditions has increased after considering temperature along with precipitation. The influence of temperature is more in causing moderate and severe drought events. The performance of agricultural standardized precipitation evapotranspiration index (aSPEI) is better than SPEI for analysing the agricultural drought characteristics. The future drought events are identified which have negative impact on crop yield considering critical drought point of different regions. The characteristics of hydrological drought were evaluated considering climate variable along with catchment variables. The catchment variable, base flow index has higher influence on short term hydrological drought where, pastureland has significant control over medium term drought. The average precipitation during the spring has potential influence on the average drought duration, where, the average precipitation during the summer showed a significant control on the long term drought duration. Overall, the decreasing trend of water availability in the catchment is likely to intensify further with fewer runoff losses in the form of streamflow. On the other hand, the crop is expected to suffer from moisture stress owing to frequent alternate dry spells and unexpected inundation due to frequent flash floods, due to intensive rainfall across the basin during monsoon season. Frequent irrigation is required during the non-monsoon period because of increased ET in this period