1. Ph.D Theses

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Design and Evaluation of Controllers for Wave Energy Based Electricity Generation System
(National Institute of Technology Karnataka, Surathkal, 2013) U., Vinatha; Vittal, K P
The research work presented in this thesis is an effort to recognize the potential issues associated with harnessing wave energy based on oscillating water column principle. A model of oscillating water column based on energy balance concept is proposed. Dynamic model of a wave energy conversion system based on OWC principle consisting of a variable speed Wells turbine driven permanent magnet synchronous generator connected to the grid by means of back to back converters is developed. Results exhibit the randomness in the various quantities like speed of the turbine, torque and powers developed of the turbine and the generators when the input to the system is varying randomly. This demonstrates uncertainty in the wave power due to arbitrariness in the waves and reveals the difficulties in developing an efficient wave harnessing system. Controllers for the generator side and the grid side converters for a grid connected wave energy conversion system are developed. The overall scheme is evaluated under steady state, dynamic and transient operating conditions. Under different operating conditions it is observed that the control scheme provides a good response in terms of power quality and power control. An important constituent for developing the wave energy conversion systems is the Wave Turbine Emulator. It offers a controllable test environment that allows the evaluation and improvement of control schemes for electric generators without construction of costly turbine and help in determining the strength and weakness of energy conversion scheme and the related control technologies. In view of this a wave turbine emulator is designed. For the realization of the wave turbine emulator a three phase permanent magnet synchronous motor is used with VSC controller as a drive. Results presented for different wave pattern as input indicates that the speed dynamics of the wave turbine model is exactly followed by wave turbine emulator developed in laboratory. An attempt is also made to study the behavior of the three phase permanent magnet synchronous generator coupled to the emulator developed.
Newton Type Methods for Lavrentiev Regularization of Nonlinear Ill-Posed Operator Equations
(National Institute of Technology Karnataka, Surathkal, 2013) Pareth, Suresan; George, Santhosh
In this thesis we consider nonlinear ill-posed operator equations of the form F(x) = f; that arise from the study of nonlinear inverse problems, where F : X ! X is a nonlinear monotone operator defined on a real Hilbert space X: In applications, instead of f; usually only noisy data fδ are available. Then the problem of recovery of the exact solution ^ x from noisy equation F(x) = fδ is ill-posed, in the sense that a small perturbation in the data can cause large deviation in the solution. Thus the computation of a stable approximation for ^ x from the solution of F(x) = fδ; becomes an important issue in ill-posed problems, and the regularization techniques have to be taken into account. Approximation methods are an attractive choice since they are straightforward to implement, for getting the numerical solution of nonlinear ill-posed problems. Thus in the last few years more emphasis was put on the investigation of iterative regularization methods. We consider Newton type iterative regularization methods and their finite dimensional realizations, for obtaining approximation for ^ x in the Hilbert space and Hilbert scales settings. We use the adaptive scheme of Pereverzyev and Schock (2005), for choosing the regularization parameter.
Voltage Regulation of Power Distribution System with Interconnected Distributed Generators
(National Institute of Technology Karnataka, Surathkal, 2013) Shivarudraswamy, R.; Gaonkar, D.N.
In the recent years the electrical power utilities are undergoing rapid restructuring process worldwide. Indeed, with deregulation, advancement in technologies and concern about the environmental impacts, competition is particularly fostered in the generation side thus allowing increased interconnection of generating units to the utility networks. These generating sources are called as distributed generators (DG) and defined as the plant which is directly connected to distribution network and is not centrally planned and dispatched. Various new types of distributed generator systems, such as microturbines and fuel cells in addition to the more traditional solar and wind power are creating significant new opportunities for the integration of diverse DG systems to the utility. Inter connection of these generators will offer a number of benefits such as improved reliability, power quality, efficiency, alleviation of system constraints along with the environmental benefits. In order to achieve these benefits with large penetration of DG source in existing utility networks several technical problems are to be fronted such as voltage regulation, islanding of DG, degradation of system reliability, power quality problems, protection and stability of the network. These issues need to be resolved, to pave the way for a sustainable energy future based on a large share of DG and hence a lot of research effort is required. Among the above issues the voltage rise problems have been reported as the foremost concern against the connection of large amounts of distributed generators to mediumvoltage and low-voltage distribution networks. The distribution systems have been planned and designed for unidirectional power flow and operated at constant voltage levels. The connection of the large amount of DG systems to the utility may reverse the power flow resulting in voltage rise above the statutory limits. Present network design practice is to limit the generator capacity to the level at which the upper voltage limit is not exceeded with maximum generation and minimum load. This can lead to a reduction in connectable generation capacity, under utilization of appropriate generation sites. The conventional voltageregulation methods of distribution system are designed with unidirectional power flow in mind and are not going to be effective in presence of a significant number of DG systems. Thus there is a need to redesign these methods to take care of bidirectional power flow or new methods have to be developed to accommodate the large number of DG systems. Thus, development of new voltage control devices/schemes have the potential to revolutionize the control of distribution network. In this thesis steady state voltage rise problem in a distribution networks interconnected with DG is examined. Case studies are presented using simulation results to study the impact of location, magnitude and operating condition of the integrated DG. The impact of other factors such as voltage at the primary substation, distance from the primary substation, demand on the system, type of loads and loading conditions on voltage level of distribution system are also analyzed. A comprehensive study on voltage control in a distribution system by taking in to account a number of DG systems and capacitors under various conditions is also presented in this work. In order to prepare the distribution networks for larger penetration of DG systems, effective voltage regulation methods are required so as to keep the voltage levels within the limits. In this work sensitivity analysis and participation factor based approaches for voltage regulation of typical distribution system are presented. The formulation for determination of voltage sensitivity index for voltage control is also given. The effectiveness of the developed approaches for voltage regulation of typical IEEE 69 bus distribution is analyzed using case studies. The OLTC, switched capacitors and DG systems are considered to regulate the voltage level in the distribution system in this study. Both methods can be used to handle all types of radial distribution system structures regardless of the system size proficiently. Individual control of various voltage regulating device such as OLTC, shunt capacitor including DG in a distribution system may cause unnecessary operations, and consequentlywear, energy consumption as well as voltage disturbances. Thus coordination among these devices for effective voltage regulation can lead increase in number of DG interconnection to utility network. In this work a coordinated regulation method using genetic algorithm is developed. Genetic algorithm is utilized to determine the optimal amount of operation for individual voltage regulating device for given distribution network. The performance of the developed method is analyzed using simulation results through two case studies. The sample load conditions using time varying load profile is considered. The multiple voltage regulating devices such as OLTC, LRT, SC, SVC including DG system is considered in this study. The input load data is very critical for distribution system load flow studies. In most cases time varying load data is required for accurate load flow analysis such as hourly load day for a day or a month. The use of this large data for load flow analysis can complicate the solution approaches. Thus in most of the cases, for validation of voltage regulation methods few samples of data are considered instead of considering the entire load profile. This approach may not accurately represent the load variation of entire profile for load follow analysis. In this work a fuzzy clustering technique for load profile generations is presented. Load profile generation using fuzzy clustering can be more realistic case rather than considering sample load conditions from set of time varying data. Fuzzy clustering is used to find 3 prototypes of hourly load data for a day (24 vectors) instead of considering sample load conditions directly from profile. Load profile generation using fuzzy clustering can be more realistic case as it considers the similarity of variation for entire set of load data. The performance of coordinated voltage control method is analyzed using the load profile generated using fuzzy cluster in this work. Distribution systems are usually unbalanced due to unbalanced loading of the different phases. Besides industrial or domestic customers some distributed generators can also impose an unbalanced operation of electrical networks. Load flow analysis of balanced radial distribution systems will be inefficient to solve the unbalanced cases and the distributionsystems need to be analyzed on a three phase basis. In this thesis load flow solution for a unbalanced system using forward and back sweep method has been presented. The detailed modeling of various components of the distribution system for the unbalanced load flow solution is also given. The performance of the coordinated voltage regulation method using two Case studies using IEEE 13 and 25 bus unbalanced distribution is analyzed through simulation. The simulation results are reported to evaluate the effectiveness of the developed method in voltage regulation of unbalanced distribution system.
Synthesis and Characterization of Thiophene Based Conjugated Polymers for Optoelectronic Applications
(National Institute of Technology Karnataka, Surathkal, 2013) M.G., Murali; D., Udaya Kumar
In the last three decades, a great deal of attention has been focused on the synthesis of conjugated polymers, because of their significant applications in the field of optoelectronic devices. In this context, the present research work is concentrated on design and synthesis of five new series of thiophene based donor-acceptor (D−A) conjugated polymers (P1−P12) for optoelectronic applications. The chemical structures of the polymers are designed by the selection of proper electron donor and electron acceptor units and they are synthesized using multistep synthetic routes. The newly synthesized intermediate compounds, monomers and polymers are characterized by 1H NMR and FTIR spectroscopic methods as well as using elemental analyses. All the polymers are thermally stable up to 300 oC under nitrogen atmosphere. The linear optical properties of the polymers are studied by using UVVisible absorption and fluorescence emission spectroscopic techniques. The optical band gap of the polymers is in the range of 1.70 − 2.63 eV. The electrochemical redox behavior of the polymers is investigated by cyclic voltammetry. The electrochemical studies reveal that polymers posses low-lying HOMO and low-lying LUMO energy levels. The preliminary studies on the electroluminescent properties show that polymers P5, P9, P10 and P12 emit red, green, green and white light respectively with lower threshold voltages. The photovoltaic properties of the low band gap polymers P6 and P7 are evaluated by fabricating bulk heterojunction solar cells using polymer as both electron donor and acceptor material. The devices exhibit satisfactorily good power conversion efficiency with high open circuit voltage. The nonlinear optical properties of the polymers are studied using z-scan technique. They show strong optical limiting/saturable absorption behavior. Polymers P1 and P5 are used to prepare polymer/TiO2 nanocomposite films and their nonlinear optical properties are studied. The incorporation of TiO2 nanoparticles into the polymer matrix marginally enhances the nonlinear absorption of the polymer.
Doping of Vacuum Deposited Zinc Oxide Thin Films
(National Institute of Technology Karnataka, Surathkal, 2013) Palimar, Sowmya; Shivakumar, G. K.; Bangera, Kasturi. V.
The main objective of present work is to study the doping of vacuum evaporated zinc oxide (ZnO) thin films. Initially, optimum conditions required to obtain good quality of undoped ZnO thin films is determined by depositing films using two evaporation sources (boats) namely molybdenum and tungsten and annealing them under different conditions. Compositional analysis of films showed incorporation of boat atoms in to ZnO thin films prepared using molybdenum as well as tungsten boat. A considerable reduction in atomic percentage incorporated boat atoms on annealing was observed in both cases. ZnO thin films obtained under optimum conditions were found to be amorphous in nature with good combination of visible region transmittance of up to 90% and room temperature conductivity of 92 Ω−1cm−1. XPS analysis has shown that the film is approximately stoichiometric with slight oxygen deficiency. From the measurements of activation energy it is observed that ZnO thin film is having two donor levels below the conduction band. Further, ZnO films are doped with third group dopants to improve their n-type conductivity. Investigation has been carried out to know the optimum percentage of dopnat to be added to retain the transmittance of the film. Role of third group elements as n-type dopants in the form of pure metals and metal oxides is studied by doping the film with indium and indium oxide separately. It is observed that contribution of indium oxide dopants is more than indium dopants in improving the conductivity of films. ZnO films were then doped with other two third group oxides, namely gallium oxide and aluminum oxide. From structural, optical and electrical properties of these oxide doped ZnO films it is found that all films have smooth surface with visible region transparency of above 90% and significantly high room temperature conductivity of the order of 103 Ω−1cm−1, which are well suited for the application of transparent electrodes.
Brand Equity for Leveraging Business Performance of Fast Moving Consumer Goods Companies
(National Institute of Technology Karnataka, Surathkal, 2013) Mohan, Bijuna C; Sequeira, A.H.
Globalization and liberalization of markets, has increased the intensity of competition faced by different organizations and hence the pressure to perform better is high. In order to fight competition companies spend huge amount on brand building activities. There is a need to study the implication of these on the performance of the business. Fast Moving Consumer Goods Industry (FMCG) is one of the fastest growing industries in India. This research focuses to identify the interrelations between the customer-based brand equity and business performance for the FMCG industry in India. Brand equity was approached from the perspective of the consumer. The literature review provides little research evidence where brand equity can be leveraged for business performance in the FMCG industry. There is immense need to focus on the concept of brand equity which can be leveraged for business performance The study merges both descriptive and exploratory approaches in order to provide a comprehensive analysis of the research problem. The study used structured and clearly stated hypotheses and involved testing the objective theories by examining the relationship among the variables. These variables were measured using questionnaires. Data on both financial performance and operational performance was collected from published external secondary sources and computerized database. Samples were chosen from the five States of Madhya Pradesh, West Bengal, Gujarat, Karnataka and Punjab based on probability and non-probability sampling. Descriptive and inferential statistics was applied to analyze the data. The four components of brand equity, appears to play a more dominant role in determining a brand’s equity for FMCG products. Brand association emerged as thelargest contributor to brand equity. The results convey that measures of consumerbased brand equity are accurate reflections of business performance in the marketplace, particularly with the operational performance. Brand loyalty had the highest influence on operational performance. The findings of this study will not only enrich the field of research pertaining to the use of brand equity for leveraging business performance, but also helps brand managers of FMCG companies to manage their brands effectively and efficiently.
Geohydrological Studies of Mulki River Basin Karnataka, India
(National Institute of Technology Karnataka, Surathkal, 2013) K., Radhakrishnan; Lokesh, K. N.
Water being the vital natural resource of concern, the sustainable development of the same is of much importance at present. A river basin or a watershed is a clearly defined basic unit to understand the water resources considering groundwater and surface water as a single resource for integrated development in a given terrain. The complex relationship that exists among soils, geology, land forms, rainfall, vegetation, land use practices and the condition of water resources is better understood and managed in a river basin or watershed. Characterizing and deriving the sustainable developmental plan for watershed, demands accurate information pertaining to its land use, soil, geology, geomorphology, meteorology, hydrogeology, quality of water, etc., in spatial domain. The erstwhile Dakshina Kannada district being blessed with many watersheds and heavy rainfall needs special attention in this regard thanks to its fast development in the coastal part of India. Mulki, a typical midland draining river basin in this coastal part of Karnataka in India has been studied and analyzed in order to understand the various aspects of its groundwater resources for the sustainable development and management. To attain this, an integration of various field and laboratory data of current and historical interest have been carried out in a spatial domain with different thematic maps derived from Survey of India (SOI) Toposheets and imageries of Indian Remote Sensing (IRS) Satellites. They have been visually and digitally processed and analyzed using geoinformatic technologies and statistical analysis. The geomorphologic studies and morphometric analysis revealed that the Mulki river having a drainage area of about 350 sq. km. is a 6th order, very coarse textured, rectilinear, dendritic, midland draining basin of matured topography with high discharge capacity and meager groundwater potential. Mulki River Basin has elbow bends in its midland area other than an offset of the NE-SW trending land mark structural ridge and WNW-ESE trending lineaments indicating structural deformation into its major course. Morphometric analysis and geomorphologic evidences such as pediplain, structural ridge, lateritic plateaus (mesas) of varying geological origin and time, waterfall, high sinuosity, cross bedding, meandering course and elbow bends inAbstract x Geohydrological Studies of Mulki River Basin, Karnataka, India. Ph.D. Thesis-2013 Department of Civil Engineering, National Institute of Technology Karnataka, Surathkal the middle stretches, river terraces, water pooling, etc., suggest neotectonic activity in this area which may be responsible for the groundwater storage and movement. The geology of the study area depicts rocks of Archaean to the Recent age, exposing fifteen lithological units representing Sargur group and Peninsular Gneissic complex of Archaean age, South Kanara Granite batholith, younger intrusive basic dykes and acid veins of Palaeoproterozoic age, laterites of Cenozoic age and coastal sands of Quaternary period and the Recent sediments of the alluvial deposits. But predominantly the rocks like Granite/Granitic gneisses with occasional laterite capping and unconsolidated river and marine sediments, occupy the area. Basic intrusives like dolerite and gabbro, and acidic intrusives like pegmatite and quartz veins are found at many places shaping the hillocks, ridges and mounds in the terrain. Many sets of joints are parallel to the river course in the ENE-WSW directions other than NE-SW, N-S, E-W and NW-SE which influence or guide the groundwater potential of the area. The NNW-SSE trending dolerite dykes are numerous and relatively abundant in granite. Foliations and joints in rocks dip either north or northeast directions favouring groundwater storage and movement in the upstream directions. Geology of the area and lineament studies confirm the earlier report of three active faults in the area which are responsible for the offset of the river and recent neotectonic activity in this area. There are some lineaments in the basin extending up to the Western Ghats which will be highly potential for groundwater explorations. NE-SW trending structural ridge of intrusive rock (mainly gabbroic) forms a major lineament in the eastern part of the basin. There are about seven genetic types of soils spread over the basin, broadly divided into four types depending on geohydrological condition as alluvial soils, loamy soils, gravelly clayey skeletal soil and lateritic soils of different encrustations. The soils and geological structures such as lineaments and joints in the otherwise hard and impervious rocks have an influence on the geohydrological conditions of this study area. Water quality, being an important criteria for deciding the suitability for drinking and irrigation purposes, about 21 important physico-chemical water quality parameters (of groundwater and surface water) have been analyzed and seven irrigation water quality parameters have been computed for 154 randomly selected water samples collected during pre-monsoon seasons of 2008 and 2009; and 95 samples collected during postmonsoon period of 2009 to understand the utility values of the same and its spatial variation. Statistical analysis of the above parameters and a comparison with acceptable drinking water quality standards revealed that most of the water samples collected during pre- and post-monsoon periods found to have quality parameters well within permissible limits. However, the spatial variation maps of vulnerable parameters and vulnerability map of water quality has been prepared, and it has been found that certain parameters like Fe, Ca, Chloride, pH, TDS, Total Hardness and Turbidity were beyond permissible limit of potable water during pre-monsoon period especially near to the coast. Salt water intrusion has taken place up to about 7 km. from the coast along the river course. The majority of the post-monsoon water samples are found to be acidic in nature influenced by the geology of the area. The drinking water qualities of surface water sources during pre-monsoon have been affected more compared to groundwater sources in the study area. There is a significant difference between the bore well water chemistry and open well water chemistry, as well as the pre-monsoon water quality and post-monsoon water quality. Bore well waters, except near the coast, are influenced by the silicate weathering of the igneous rocks, whereas the open well waters are influenced by the clay mineral reaction except those near the coast, influenced by the chloride dissolution from the salt water ingression in the study area. The total hydrochemistry in the study area is dominated by alkaline earth (64%) and strong acids (55%) with carbonate hardness (33%) (secondary alkalinity) and primary salinity (26%) influenced by the weathered granitic gneisses and leached laterite besides the influence of saline water. During pre-monsoon season Rock interaction Domain is having a dominating influence on the groundwater whereas in post-monsoon season Precipitation domain influences open well water. The difference in the hydrochemistry during pre-monsoon and postmonsoon periods indicates the influence of weathering, infiltration, mixing and leaching in the study area. A great variation is noticed in irrigation water suitability based on different characteristics and is found to be 95% (pre-monsoon) and 100% (post-monsoon) based on EC, 100% (pre-monsoon) and 98% (post-monsoon) based on SAR, 84% (pre-monsoon) and 33% (post-monsoon) based on % Na, and 60% (pre-monsoon) and 03% (post-monsoon) based on RSC. All groundwater samples fall under no problem category of sodium water type irrigation quality with low to medium salinity. Therefore, they can be used for irrigation on all types of soil with little danger of exchangeable sodium. An analysis of the Water Quality Indices (WQI) and its mapping in spatial and temporal domain in the study area found to be a faster and better tool in assessing and rating the suitability of groundwater for drinking water based on quality weightage. The very high WQI at the coastal front near the mouth of the river and its extension along the river course upstream up to a certain distance during pre-monsoon indicates the influence of saline water and its migration along tidal water in this area. The temporal variation in distribution pattern and density of WQI points to the significant role of precipitation and infiltration playing in the determination of water quality. As a part of systematic identification, quantification and management of regional hydrologic regime, geophysical investigations especially Vertical Electrical Soundings (VES) have been carried out at about 129 selected stations representing different terrains in the basin to understand the subsurface lithology, groundwater quality and aquifer characteristics at different depths. The data has been interpreted using resistivity cross sections and correlated with a few available drilled data/geology of the area in order to understand the aquifer characteristics and resource potential. Saline water ingression studies also have been carried out using these data along the coastal stretch. From the hydrometeorological analysis, the study area is found to be falling under tropical humid climatic zone where hot humid climate prevails throughout the year. The rainfall of the study area falling in the wet climatic zone is uneven and shows an overall decreasing trend for the last four decades. From the last four decade’s rainfall data analysis, the average annual rainfall is found to be about 4264.09 mm falling in the wet climatic zone giving rise to an average volume of about 1496.70x106 m3 storm water per annum in the basin. The rainfall spread for about five to six months in the study area shows spatial and temporal variation in its distribution with a minimum of 66 days at Mulki during 1973 to 161days at Karkala during 1978. The average daily rainfall also found to be varied from 12.3mm during 1973 to 53.2mm during 1997. A balance in distribution of rainfall found to be characteristic of this area where deficient years or dry years almost equaled the wet years in all three point stations during the 30 years observations period. Temporal and spatial variations in rainfall have been noticed in the study area, where 87% of rainfall is contributed from southwest monsoon spread over a period of four months and the decrease in trend is from Karkala to Mulki in a northeast to southwest direction. However, the moving average curve of rainfall denotes a nine year trend of continuous variation in its pattern and periodicity. The frequency probability analysis of magnitude and return period of rainfall in the basin demonstrate that rainfall above 3176.9mm have a chance of returning every year with 67% to 98% dependence. The computed water budget of the area shows an actual evapotranspiration of 30% of rainfall against the maximum potential evapotranspiration of 46.6% and a runoff about 771.16 x 106 cubic meters per annum from the study area. Groundwater assessment and management studies revealed that there is a surplus availability of storm water and groundwater balance in the 43 villages of the 17 Panchayats falling in the Mulki River basin, but not managed properly underutilizing its huge potential. Estimation of groundwater recharge and potential has been carried out using water table fluctuation data obtained from three observation wells other than 36 observation wells periodically monitored for a period of one year. The average annual decline in the water table of the study area is found to be about 6.85m during last one decade giving rise to a draft of 2,404.35x106 cubic meters per annum. Approximate water demand and utilization has been estimated based on Village Panchayat resource data. Even with a net annual recharge of 24,302 ha.m. of groundwater available for development in the study area, the annual net draft for utilisation from the aquifer is estimated to be 993.93 ha.m. only and a balance potential of 23,308 ha.m. is available for future utilization, but unevenly distributed in the area and lost as groundwater flow. Cultivated area of about 27% in the basin has been found in clustered strips irrigated by a good practice of rain fed traditional structures like tanks, ponds, etc. About 73 such structures ideally located with a concentration of one in 4.8 sq. km. spread over an area of 13.5 hectares with a maximum storage capacity of 0.23 MCM have been identified, delineated and mapped from the study area. Rehabilitating old Rainwater Harvesting Structures (RWHS) and increasing the density of tanks at the rate of at least one in one sq km. area can use more than 50 per cent of the runoff water considering the future needs of development. Case studies carried out to understand the viability of these resources proved these to be very effective. About 56 microwatersheds, significant in the sustainable development, spread over an area of about 46.14 sq. kms. comprising 13% of the Mulki River basin have been identified and delineated. Development of microwatersheds along with rehabilitation of abandoned and silted traditional rainwater harvesting structures found to be an efficient management practise to improve the water resource of this area for drinking and irrigational purposes. Geoinfomatic application found to be a very useful tool in the preparation of various thematic maps and integration of data for efficient planning and management of the water resources in the study area for sustainable development.
Studies on Corrosion Inhibition of 18% Ni M 250 Grade Maraging Steel under Weld Aged Condition in Acidic Media
(National Institute of Technology Karnataka, Surathkal, 2013) B. S., Sanatkumar; Shetty, A. Nityananda; Nayak, Jagannatha
The corrosion behaviour of 18 % Ni M250 grade maraging steel under weld aged conditions in two different acid media, namely, hydrochloric acid and sulphuric acid in various concentrations and temperatures have been studied by Tafel polarization and electrochemical impedance spectroscopy techniques. The corrosion rate in the sulphuric acid medium was higher than in the hydrochloric acid medium. Five organic inhibitors were synthesized and characterized using spectral and elemental analysis. The five inhibitors were 1(2E)-1-(4-aminophenyl)-3-(2-thienyl) prop-2-en-1-one (ATPI), 2-(4-chlorophenyl)-2-oxoethyl benzoate (CPOB), 2-(4- bromophenyl)-2-oxoethyl- 4-chlorobenzoate (CPOM), (E)-1-(2,4-dinitrophenyl)-2-[1- (2-nitrophenyl) ethylidene] hydrazine (DNPH) and 5-diethylamino-2-{[2-(2,4- dinitrophenyl) hydrazin-1-ylidene]methyl} - phenol (DDPM). The results pertaining to the corrosion inhibition studies of five inhibitors in two different acid media at different temperatures in the presence of varying concentrations of inhibitors are reported in the thesis. Activation parameters for the corrosion of the alloy and thermodynamic parameters for the adsorption of the inhibitors have been calculated and the results have been analysed. The adsorption of first four inhibitors on the alloy was through both physisorption and chemisorption, with predominant physisorption in both the media. The mode of adsorption for the DDPM predominantly chemisorption in both the media. The adsorption of all the five inhibitors on alloy surfaces follows Langmuir adsorption isotherm. The inhibition efficiencies of first four inhibitors decrease with the increase in temperature, the inhibition efficiency of DDPM increases with the increase in temperature.
Design Consistency Evaluation of Rural Highways
(National Institute of Technology Karnataka, Surathkal, 2013) N.J, Sowmya; Ravishankar, A.U.
Rapid growth of population and increasing economic activities are the twin factors that contribute to the tremendous increase in the vehicle population which, in turn, contributes to the growing number of road accidents. Road accidents are complex events involving a variety of factors, including highway geometry, driver behaviour, weather conditions, and speed limits. Several studies have been conducted to determine the relationship between factors associated with accidents and their effect on safety. Improving highway design consistency is considered to be an important strategy for improving traffic safety. Geometric design consistency evaluation is a widely used method of determining sections of highways which require alignment improvement. Identifying and treating any inconsistency on a highway can significantly improve its safety performance. A critical factor in highway design is maintaining a good consistency with a road geometry that meets the driver’s expectations. Considerable research has been undertaken to explain this concept, including identifying potential consistency measures and developing models to estimate them. However, considerable amount of work has not been carried out to evaluate the geometric consistency in India. Rural roads constitute about 80 per cent of Indian road network. Therefore, rural road safety accounts for a considerable share of the total road safety problem. In Dakshina Kannada District, and even in Karnataka state, intermediate lane highways make more than 50 per cent of the principal road network. The majority of these intermediate lane rural highways are historical routes and many of them do not follow a specific design code. Therefore, road safety of intermediate lane roads is a very important issue in the development of the country. This study aims to enhance the safety of these existing highways based on an understanding of actual driving behaviour by means of field data measurements, and to verify their conformance to a consistency evaluation model. Both horizontal and vertical alignments are the main focus of this study. The horizontal alignment of a road consists of a straight tangent followed by horizontal curve, whereas the vertical alignment of the road consists of a level section followedvii by a vertical curve. This study deals with developing appropriate design consistency evaluation criteria of horizontal and vertical curves using geometric, speed, and accident data of eight intermediate lane rural highways. Geometric details of a road were collected from the field and CAD (Computer Aided Design) drawings were prepared using the details of surveying. A spot speed survey was conducted for passenger cars on the approach tangent and at the beginning, middle, and end points of horizontal curves and on the approach tangent, limiting point and summit point of vertical curves. The accident details were collected for six years (from 2005 to 2010) from different police stations. The operating speed prediction models were developed for both horizontal and vertical curves. The speed change experienced by the same driver from tangent to curve i.e. speed differential was also studied for horizontal curves, and the models were developed to predict this change. Consistency evaluation criteria for horizontal curves and vertical curves were also developed to enhance the safety of the alignment. Alignment indices, are the another set of quantitative measures, were used to identify the inconsistencies that exist on intermediate lane rural highways. Finally, an attempt was made to develop the relationship between safety and alignment indices.
Preparation, Characterization and Performance Study of New Polysulfone Based Nanofiltration Membranes for Water Filtration
(National Institute of Technology Karnataka, Surathkal, 2013) Padaki, Mahesh S.; Isloor, Arun M.
Nanofiltration (NF) is a membrane based liquid separation technology which displays separation characteristics in the intermediate range between Reverse Osmosis (RO) and Ultrafiltratiom (UF). RO is capable of producing very clean water and high concentrate rejection. UF may be used for removal of suspended solids and large organic molecules. Most of the membranes were prepared from organic polymers. Inorganic polymers tend to be expensive. Cellulose derivatives, polysulfone, polyamides polyvinyldifloride are presently available polymers which are being extensively used for membrane preparation. For membranes to be competitive with conventional technology, a membrane process needs to operate with a high rate of flux, high degree of selectivity and high resistance to fouling. There are three main areas of interest when it comes to improving membrane performance: the synthesis process, post-synthesis modification and application process. These three processes were focused and discussed in present work. Synthesis of polymers, chemical modification of polymers and surface modification of the membranes were performed and discussed in this thesis. Polysulfonylaminobenzamide (PSAB), methylated polysulfonylaminobenzamide (mPSAB), poly[(4-aminophenyl)sulfonyl]butanediamide (PASB) and methylated poly[(4-aminopheonyl)sulfonyl]butanediamide (mPASB) were synthesized. Chitosan (CS) was modified into N-Phthaloyl chitosan (NCS) and polysulfone (PSf) was modified into sulfonated polysulfone (sPSf). These polymers were blend with polysulfone for the preparation of NF membranes. Surface modification was mainly carried out by chemical modification, physical vapor deposition and beam irradiation. The general properties of prepared membranes fall in UF and NF regime. The properties varied depending on the nature of the polymer, the functional group present in the polymer and manufacturing process. It was shown that the novel polymers and polymer modification enhanced the performance of the membrane.
Web UR: Effective Techniques For Web Usage Mining And Recommender System
(National Institute of Technology Karnataka, Surathkal, 2013) G., Poornalatha; V. S, Ananthanarayana; Raghavendra, Prakash S.
The proliferation of internet along with the attractiveness of the web in recent years has made web mining as the research area of great magnitude. Web mining essentially has many advantages which make this technology attractive to researchers. The analysis of web users’ navigational pattern within a web site can provide useful information for server performance enhancements, restructuring a web site, direct marketing in e-commerce etc. This thesis discusses an effective clustering technique that groups user sessions, by modifying k-means algorithm. The proposed distance measures namely, the variable length vector distance, sequence alignment based distance measure, and hybrid sequence alignment measure are explained. The results obtained are validated. The present work attempts to solve the problem of predicting the next page to be accessed by the user based on the mining of web server logs, that maintains the information of users who access the web site. The proposed model yields good prediction accuracy compared to the existing methods like Markov model, association rule, ANN etc. A recommender system based on session collaborative filtering is proposed. The proposed recommender system is compared with a few other recommender systems by using precision and recall as metrics, and a better performance is observed. The outcome of prediction and recommender system could be used to suggest any structural modifications to the web site.
Electrical Power Distribution System Management Under Deregulation Regime
(National Institute of Technology Karnataka, Surathkal, 2013) Manjunatha Sharman, K.; Panduranga Vittal, K.
The distribution system in the electrical power network is the most vital section being nearest to the consumers. The effectiveness of the power delivery to the loads is governed by the design, operation and maintenance of the distribution network. Over the years, the researchers are attempting to achieve improvements in the distribution system performance by adopting newer topologies, strategies for network design and control. In this context, globally the need for distribution system improvement is acknowledged by all countries and since past decade distribution sector reforms are being executed by initiating newer government policies which led to de-regulation regime worldwide. This thesis addresses the issues of DG insertion to distribution system in deregulation regime. The analysis carried out evaluates the feasibility of an Industrial captive power plant to operate as a DG Source, complex issues associated with multiple DG sources insertion to distribution system and impact of DG sources in network reconfiguration. A tool which facilitates decision on power export by an industrial captive power plant to grid has been developed. This tool accounts existing load pattern and generation scenario of the industrial unit. The proposed analytical approach gives with emphasis on choice of improving any specific parameter from either technical or economical perspective. The strategic technique developed proposes a comprehensive index termed as Network Performance Enhancement Index (NPEI). This index is a combination of indices related to loss reduction, voltage profile improvement, voltage regulation, voltage stability. Adapting this index provides enough alternatives to the designer so that he can decide on the most feasible solution. The technique designed for service restoration enumerates the situations of islanding of DGs due to fault in any part of network and guides the operator for supply of local loads in such a situation. This work proposes most feasible schemes for DG insertion to overcome the difficulties in implementation of the conventional fixed solutions schemes. The software tools adopted are SKM Power Tools and MATLAB and all evaluations are done using standard bus structures reported in literature and nearby captive plant data of an industry.
Design and Construction of Algebraic Codes for Enhancing Information Integrity in Data Storage Systems
(National Institute of Technology Karnataka, Surathkal, 2013) K, Rajesh Shetty; Sripati, U.
Data storage devices have become ubiquitous in present day information driven society. It is essential that storage devices exhibit very high levels of data integrity. Therefore, data integrity is a fundamental aspect of storage, security and reliability. NAND and NOR Flash memories [Chen, Y. 2008], [Mielke, N et al. 2008], [Gal, E. et al. 2005], [Jiang, A et al. 2010] are widely used for data storage because of their compactness and low power consumption. Data stored in non-volatile memory is usually critical to proper system operation, and corruption of data can lead to system failure. Hence data corruption is a major concern in applications that rely on nonvolatile memory for long-term data storage. Many techniques have been employed to improve the reliability of these devices. These techniques can be divided into two categories. In the first approach, improvements are carried out in the fabrication process to reduce the Raw Bit Error Rate (RBER). The second option is to use Error Correction Techniques to improve the RBER level to levels that are deemed acceptable to most users [Sun, F. et al. 2007], [Sun,F et al. 2006], [Chen, Y. and Parhi, K. 2004], [Mielke, N. et al. 2008]. Error Control Code (ECC) techniques (i.e., techniques capable of detecting and correcting errors in processed and stored data by using redundant bits in addition to information bits according to a given coding strategy) [Pless, V. and Huffman, W.C. 1998] have been commonly used at board level for many years to enhance the reliability of memory systems [Bertozzi, D. et al. 2005]. However, as memory chips become denser, they also become more prone to errors, as a consequence of both the reduced cell size and the increased cell count within a single die. Moreover, read and write operations are made more critical by both technology scaling down and higher speed requirements. On the other hand, higher and higher reliability is required for storage systems in a large variety of applications. Generally high storage density is achieved by reducing the size of the elementary memory cell. However, for non-volatile memories, some physical phenomena makesv an aggressive reduction of the memory cell size difficult [Atwood, G. et al. 1997], [Wang, Z. and Karpovsky, M. 2011]. An alternative solution to reduce the cost per bit and increase the storage density is to adopt the multilevel approach. It consists of placing a multiplicity of charge amount in the floating gate, thus allowing the cell to store more than one bit. However, the multilevel storage requires the consideration of three basic issues: (i) accuracy of write operation (necessary to place the correct amount of charge of the floating gate). (ii) precision of the charge sensing (required to discriminate the different threshold voltages). (iii) stability of charge over an extended time period. Although Multi Level Cell (MLC) memory has higher density than Single Level Cell (SLC) memory, MLC is more vulnerable to errors because small fluctuation of the charge amount in the floating gate and slight variation of gate voltage result in misreading of stored data [Sun, F. et al. 2007], [Sun,F et al. 2006], [Maeda, Y et al. 2009], [Lin, H et al. 2002], [Ankolekar, P. P et al.2010]. ECC is a cost effective method to enhance the integrity of data storage systems. Very stringent values of application BER, which would ordinarily require complex and expensive fabrication techniques as well as expensive materials, can be met very easily by employing ECC. Storage devices characterized by high RBER values can be made to yield application BERs as small as desired by the use of suitable ECC techniques. The fraction of erroneous bits that remain uncorrected after applying ECC constitute the uncorrectable bit error rate (UBER). UBER is a useful reliability metric for data storage devices and is used to specify the data corruption rate in the information given to the user after correction by ECC algorithms. ECC algorithms can also correct errors that may manifest at any later stage during the life of the device. Hence use of ECC techniques has been widely accepted by the semiconductor manufacturing industry to enhance the RBER to levels demanded by applications. In this thesis, we have made an attempt to synthesize a number of codes for use in data storage systems with error correcting capability exceeding the state of art asvi specified in the industry documentation. In the initial part of the thesis, the focus is on the synthesis of codes for enhancing data integrity in flash memories composed of SLCs. While studying the flash memory organization, two memory models, namely Memory model 1 and Memory model 2 are identified and the codes are synthesized separately for these memory models. As compared to the current standard, [Mehnert, A. 2008] where six bits in errors can be corrected over a span of 4096 information bits (one sector), we propose codes that can correct up to nine bits in error per sector. The various generator polynomials are computed. As the performance of the error control code improves with increase in length, we were motivated to consider the combination of two sectors to constitute the information block. For this scenario, we propose codes that can correct up to eighteen bits in error over a span of 8192 bits (two sectors). Further, using Memory model 2, we have synthesized and proposed codes that can correct up to eighteen bits in errors per sector. The performance of these codes is quantified by computing values of the probability of decoding error. To summarize, the main objective of this work has been to design, construct and synthesize a large group of codes which can be used to enhance the data integrity levels associated with flash memory devices so as to make them useful in a wider class of applications. With a view to make these synthesized codes, readily acceptable to industry, we have strictly adhered to the memory architecture specified in the literature.
Electrochemical Development and Characterization of Mutual Alloys of Iron Group Elements
(National Institute of Technology Karnataka, Surathkal, 2013) G.P., Pavithra; Hegde, A. Chitharanjan
This thesis titled ‘Electrochemical development and characterization of mutual alloys of iron group elements’ details a comprehensive approach for electrodepositon mutual alloys of Fe-group metals by a relatively inexpensive, but advanced method called composition modulated multilayer alloy (CMMA) coating method. The coating has been accomplished galvanostatically on copper using Single Bath Technique (SBT). The essential feature of this method is their tailored micro/nano structured layers with alternatively changing composition is responsible for improved corrosion resistance of the coatings. The project involves optimization of three new binary baths of mutual alloys Fe-group metals and their multilayer coatings using direct current (DC) and pulsed current, respectively. The plating conditions and operating parameters have been optimized for best magnetic and corrosion performance of monolayer (non-nanostructured, or bulk) alloy coatings. As an attempt to increase the corrosion resistance of the monolayer coatings of Fe-group metals, namely Fe-Ni, Co-Ni and Fe-Co and multilayer coatings, represented as CMMA (Fe-Ni), (Co-Ni) and (Fe-Co) have been accomplished using square current waves having dual and triple pulses from respective baths (optimized). Multilayer coatings with different configurations have been developed with different combination of current densities, called cyclic cathode current densities (CCCD’s) and number of layers. All depositions were carried out galvanostatically on copper from the respective baths for 10 minutes. Boric acid (BA), ascorbic acid (AA) and sulphanilic acid (SA) were used, as common additives to impart better appearance. The corrosion behaviors of the coatings were evaluated in 1M HCl, as representative aggressive corrosion medium by electrochemical AC and DC techniques. The surface morphology, composition and phase structure of the coatings were characterized by SEM, EDX and XRD methods respectively. The experimental results revealed that CMMA coatings developed using dual and triple current pulses exhibit better (by several fold) corrosion resistance compared to monolayer alloys, developed from same bath for same time. The significant improvement in corrosion performance of CMMA coatings was attributed to small compositional difference in alternate layers, due to change in deposition current density. The formation of layers and their corrosion mechanism have been identified by SEM analysis. The improved corrosion protection of multilayer coatings was found to be the combined effect of compositional modulation of the individual layers and increased number of interfaces due to layering. The experimental data were analyzed, and results were discussed with Tables and Figures.
Asymmetric Synthesis of Drug Intermediates using Microorganisms
(National Institute of Technology Karnataka, Surathkal, 2013) S. R., Brahmani Priyadarshini; Mugeraya, Gopal
There has been an increasing awareness of the enormous potential of microorganisms and enzymes to transform synthetic chemicals, in a highly chemo, regio and enantioselective manner. In the present work, an attempt was made to evaluate the potential of some selected fungi species to effect reduction of selected ketones and oxidation of selected sulphides. Saccharomyces cerevisae was selected for evaluating the effect of various physicochemical parameters on the (microbial induced) biotransformation, as it showed considerable reduction of the substrate, 3-[5-[(4-flurophenyl)-1, 5, dioxopentol]- yl] –4- (S) phenyl oxazolidin-2-one. The experimental results showed that maximum reduction occurred at pH of 7.6, temperature of 30° C, incubation period of 48 hours and biomass concentration of 6 g. High concentration of substrate had a negative effect on the rate of bioconversion. It was found that the organic solvents adversely affected the enzymatic reaction, while use of surfactant had a favorable effect on bioconversion. The interaction of various culture condition variables on reductase activity was also studied using S. cerevisiae. Central composite design and Response surface methodology were used in the design of the experiments and analysis of the results. The model could be successfully used for accurately predicting enzyme activity based on a new set of independent variables. Rhizopus stolonifer was found to be effective in carrying out sulphoxidation of omeprazole intermediate and the various factors affecting the reaction were studied. The ideal reaction time for the conversion was found to be 48 hours. A substrate concentration of 0.04% was found to be well-tolerated by the microbial cell. The pH and temperature of the reaction mixture in the range selected, did not affect the enzyme activity significantly. Biosulphoxidation in water miscible solvents was significantly low while the reaction did not proceed in water immiscible solvents. Use of β-cyclodextrin and surfactants in the reaction did not increase the product yield. The study on variation in the culture conditions revealed that glucose as the carbon source was most suitable for sulphoxidation. The addition of organic nitrogen and divalent metal ion salts did not haveany significant effect on the ability of the organism in bringing about sulphoxidation. Change in initial media pH and temperature did not significantly affect bioconversion.
Groundwater Level Forecasting using Radial Basis Function and Generalized Regression Neural Networks
(National Institute of Technology Karnataka, Surathkal, 2013) D, Sreenivasulu; Deka, Paresh Chandra
Forecasting of groundwater levels is very much useful for efficient planning in integrated management of groundwater and surface water resources in a basin. Accurate and reliable groundwater level forecasting models can help ensuring the sustainable use of a watershed’s aquifer for both urban and rural water supply. The present work investigates the potential of two Neural networks, such as Radial Basis Function Neural Networks (RBFNN) and Generalized Regression Neural Networks (GRNN) in comparison to regular ANN models like Feed Forward Back Propagation (FFBP) and Non-Linear Regression Model (NARX) for modeling in Ground water level (GWL) forecasting in a coastal aquifer at western Ghats of India. Total 24 wells (both shallow and deep) located within the study area (microwatershed of Pavanje river basin) were selected covering around 40sqkm. Here, two different dataset such as weekly Time series GWL and Meteorological variables those recorded during the study period (2004-2011) were used in the analysis. Various performance indices such as Root Mean Squared Error (RMSE), Coefficient of Correlation (CC) and Coefficient of Efficiency (CE) were used as evaluation criteria to assess the performance of the developed models. At the first stage, the potential and applicability of RBF for forecasting groundwater level are investigated. Weekly time series groundwater level data upto four lagged data has been used as various input scenario where predicted output are one and two week leadtime GWL. The analysis has been carried out separately for three representative open wells. For all the three well stations, higher accuracy and consistent forecasting performance for RBF network model was obtained compared to FFBP network model. After confirming the suitability of RBF in GWL forecasting and with better accuracy over FFBP, the work has been extended further to consolidate the applicability of RBF in multistep leadtime forecasting upto six week ahead. In this study, six representative wells are covered for development of RBF models for six different input combinations using lagged time series data. Outputs are the predicted GWL upto six week. RBF models are developed for every well station and results are compared with Non linear regression model (NARX). It has been observed that for allGroundwater level Forecasting using Radial Basis Function and Generalized Regression Neural Networks, Ph.D Thesis, 2012, NITK, Surathkal, India viii the six well station, the higher and consistent forecasting performance by RBF network model in multi step week lead which consolidates the forecasting capability of RBF. The NARX model result shows poor performance. In the third stage, to examine the potential and applicability of GRNN in GWL forecasting, various GRNN models has been developed by considering the advantage of S-summation and D-summation layers for different input combinations using time series data. Weekly time series groundwater level data upto four lagged data has been used as inputs where predicted outputs are one week leadtime GWL. The analysis has been carried out separately for three representative open wells. GRNN models were developed for every well and best model results were compared with best RBF and FFBP with LM training algorithm models. The RBF and GRNN models are almost performed similarly in GWL forecasting with higher accuracy in all the representative well station. The poor performance of FFBP-LM model is also satisfactory but found inferior than both GRNN and RBF. After confirming the potential and applicability of GRNN and RBF in time series GWL forecasting with similar capability, the robustness, adaptability and flexibility characteristics of these two techniques are further investigated for suitability with cause and effect relationship. Here various meteorological parameters are used as causable variable and the GWL is used as output effect .Only GRNN models are developed in the present study as RBF was found with similar predicting performance in previous studies. Five various input combinations are used to obtain best results as one step leadtime output for three representative wells. In this case also, GRNN model is predicting groundwater level with higher accuracy and with satisfactory results. The GRNN model performance is compared to general ANN (FFBP) model and found outperforming FFBP performance. The result of the study indicates the potential and suitability of RBFNN and GRNN modeling in GWL forecasting for multistep leadtime data. The performance of RBFNN and GRNN were found almost equally good. Although accuracy of forecasted GWL generally decreases with the increase of leadtime, the GWL forecast were obtained within acceptable accuracy for both the models.
Study of Geomorphology and Dynamics of Shoreline Associated with Mulky-Pavanje Rivermouth, Dakshina Kannada Coast, Karnataka, India
(National Institute of Technology Karnataka, Surathkal, 2013) Nagaraj, Gumageri; Dwarakish, G. S.
The current thesis considered Mulky-Pavanje rivermouth and associated shoreline of about 12km length, lies between 13000'00''-13006'00'' North Latitude and 74044'00''- 74050'00'' East Longitude of Dakshina Kannda coast, Karnataka, India for short-term (<10 years), medium-term (10–60 years) and long-term (>60 years) shoreline changes. Beach survey, beach width, wave climate (height, period and direction) and wind parameters (speed and direction) and sediment sampling are gathered from nine locations (BS 1 – BS 9) to represent total 12 km shoreline, during the period from September 2009 to December 2011 for short-term change analysis. Short-term change analysis indicated that net accretion on the beaches towards the south of the rivermouth (BS 1–BS 5), whereas the north of the rivermouth experienced net erosion (BS 6–BS 9). For medium-term shoreline change analysis, rainfall and river discharges are obtained from Indian Meteorological Department for the periods 1985- 2011 and 1985-1998 respectively. The monsoonal storm directly induces rivermouth morphology to vary (BS 5–BS 6), adjacent beaches to suffer from erosion (BS1–BS 4 and BS 7–BS 9) and also leads drastic changes in wave climate and freshwater flow. During monsoon and post-monsoon periods, the rivers Mulky (North) and Pavanje (South) overflow, discharge sizeable quantities of sediments into the sea, whereas during the pre-monsoon periods, seawater enters into the rivermouth area leads sediment deposition and distribution on either side of the rivermouth. However, the discharge of the Mulky river is approximately two times more than that of Pavanje river. Because of the more flow in the Mulky river, which runs across the northern part of the rivermouth, the shoreline in the vicinity of rivermouth is predominantly shifting towards south. Additionally long-term shoreline change analyses are made through multidated satellite imageries and topomaps for the period 1912–2009. The long-term shoreline change analyses depicts that northern spit and rivermouth are shifting towards south during the period 1912–2009 and also observed that fluctuation of accretion and erosion pattern on southern side of the shoreline is highly significant as compared with northern side. The Mulky-Pavanje rivermouth being highly complex and dynamic, but it provides wide scope for developmental activities around it. Therefore Land use/Land cover changes are attempted by considering recentix decade, i.e 1998–2009 with the help of topographical map and remote sensing data. Land use/Land cover change analysis indicated that, because of development of urbanization and industrialization around the rivermouth, the built-up area has been drastically increased, while the other coastal related geological features such as beach vegetation, mangroves and river sand are drastically reduced during the period 1998– 2009. In addition, Artificial Neural Network (ANN) technique is used to model the very important parameters of the coastal engineering such as wave height and littoral drift, which cause coastal erosion in the study area. The developed NARX and FFBP models are evaluated using error statistics. In both cases the NARX model performed better than FFBP and proved that wave height and littoral drift are the direct responsible factors to cause erosion in the Mulky-Pavanje rivermouth and associated shoreline.
Design and Synthesis of New Donor-Acceptor Type Conjugated Polymers for Photonic Applications
(National Institute of Technology Karnataka, Surathkal, 2013) K. A., Vishnumurthy; Adhikari, A. Vasudeva
In recent years, a great deal of interest has been focused on the synthesis of novel D-A type conjugated polymers because of their excellent photonic properties. Recently, lots of attentions have been dedicated towards the development of new D-A type polymers with desired properties through proper structural modifications. In this context, the proposed research work has been aimed at design and synthesis of new D-A type conjugated polymers with improved photonic properties. Based on the literature review, five new series of D-A type conjugated polymers (P1-P20) carrying various electron donors and acceptor moieties have been designed. Seven series of bi-functional monomers required for the synthesis of new polymers have been prepared using appropriate synthetic procedures. Structures of new intermediates and monomers have been evidenced using spectral and elemental analyses. Starting from these monomers, five new series of target polymers, viz. (i) poly(3,4-ditetradecyloxythiophene)s carrying thiophene, naphthalene, isopthalyl, vinyl and pyrazole moieties as π-conjugated spacers (Series 1, P1-P5), (ii) poly(cyanopyridines) containing phenyl, carbazole, alkoxythiophene phenothiazine and dipenyl amine based electron donating bridges (Series 2, P6-P10), (iii) poly(3,4- ditetradecyloxythiophene)s involving vinylene π-conjugated spacers (Series 3, P11- P14), (iv) poly(3,4-ditetradecyloxythiophene)s carrying aromatic conjugated cyclic imides (Series 4, P15 and P16), and (v) poly(3,4-ditetradecyloxythiophene)s with imine functionalized electron donors as π-conjugated bridges (Series 5, P17-P20), have been successfully synthesized and their synthetic protocols have been established. Their structures have been confirmed by different spectroscopic and elemental analyses. Their molecular weights have been determined by GPC technique and thermal properties have been evaluated by TGA studies. Electrochemical properties have been studied using CV experiments. The linear optical characteristics have been estimated by UV-visible absorption and fluorescence emission spectroscopy. Their fluorescent quantum yields and solvatochromic behavior have been determined. Finally, their third-order NLO properties have been investigated using open aperture Z-scan technique to investigate their optical limiting behavior. Most of the polymers have exhibited promising results.
Response Analysis of Berthing Structures for Wave and Earthquake Induced Forces Including Soil - Structure Interaction
(National Institute of Technology Karnataka, Surathkal, 2013) Shanthala, B.; Subba Rao; Venkataramana, Katta
Countries surrounded by ocean can easily achieve tremendous progress in trade and industry provided proper planning of ports and harbours is made for transportation of goods and materials through sea transport. Rapid growth in the water transport system demands the construction of more port and harbour structures. Berthing structures are constructed in ports and harbours to provide facilities such as berthing and mooring of vessels, loading and unloading of cargo and embarking and disembarking of passengers. Berthing structures are classified as vertical face structures such as diaphragm walls and open piled structures such as jetties. These berthing structures are to be designed for berthing force, mooring force, wave force, current force, seismic force, active earth pressure and differential water pressure, in addition to self-weight of the structure and live load. The deck of berthing structure is generally supported by vertical piles Waves contribute to major loads on marine structures. Therefore it is important to quantify wave-induced load effects to ensure a reasonable, safe and robust design of berthing structures.
The piled structures are the most commonly adopted structures in shallow water and deep water. Safe operations on such structures have pressed the necessity to design them to resist the disturbing wave environment, since wave forces are random and vary with time. In the present work, an attempt is made to study the response of vertical member and a simplified piled berthing structure with and without soil structure interaction. Miniature model of such structures are tested for finding natural frequency and response to forced vibrations. All of the experimental observations are reproduced quite accurately by the simulation. It was found that inclusion of water and the soil tend to increase the natural frequency of the structure.
In this research conceptual layout of jetty for berthing 200000 DWT ship is carried out based on the available environmental data and the ship dimensions at New Mangalore Port Trust, Mangalore. Static and dynamic wave response analysis is carried out using StruCAD 3D software, considering various load combinations. Responses are estimated for various pile diameters and the results are compared. Responses are also found for 45º, 90º and 135º wave directions and it is seen that the structural response is maximum for wave direction perpendicular to the structural alignment. The detailed analysis of berthing structure, for the design significant wave height of 3. 2m and maximum wave height of 5.5 m is carried out for a full cycle of wave and responses are found out.
In order to carryout analysis of a structure under earthquake conditions a representation of the earthquake loading is essential. In such situation dynamic analysis of the structure will be required in which case accelerograms will be used given that they offer detailed representation of the ground motions during earthquakes. At the same time they provide the nature of the earthquake ground shaking. In this thesis three types of recorded accelerograms were used for the time history analysis of berthing structure with and without soil structure interaction. From the time history analysis optimum width was found for the deflection criteria. It was found that soil – structure interaction causes increase in displacements of the structure, which can cause large increase in natural period, leading to much larger relative displacements.
Computational Intelligence in Prediction of Wave Transmission for Horizontally Interlaced Multi-layer Moored Floating Pipe Breakwater
(National Institute of Technology Karnataka, Surathkal, 2013) Govind, Patil Sanjay; Hegde, Arkal Vittal; Mandal, Sukomal
Energy dissipation process of Horizontally Interlaced Multi-layer Moored Floating Pipe Breakwater (HIMMFPB) depends on various factors like pipe interference effect, the spacing between the pipes and number of layers. As the effect of all these factors on transmission is not clearly understood, it will be extremely difficult to quantify them mathematically. Furthermore, it is a complex problem, and till now there has not been available a simple mathematical model to predict the wave transmission through HIMMFPB by considering all the boundary conditions, and hence one has to depend on physical model studies which are expensive and time consuming. Computational Intelligence (CI) techniques, such as, Artificial Neural Network (ANN), Adaptive Neuro-Fuzzy Inference System (ANFIS), Support Vector Machine Regression (SVMR), Genetic Programming (GP) and Genetic Algorithm (GA) have been efficaciously proposed as an efficient tool for modelling and predictions in coastal/ocean engineering problems. For developing CI models in prediction of wave transmission for HIMMFPB, data set were obtained from experimental wave transmission of HIMMFPB using regular wave flume at Marine Structure Laboratory, National Institute of Technology, Karnataka, Surathkal, Mangalore, India. These data sets are divided into two groups, one for training and other for testing. The input parameters that influence the wave transmission Kt  of floating breakwater, such as, relative spacing to pipesS D, relative breakwater widthW L, ratio of incident wave height to water depthHi d, incident wave steepness Hi L are considered in developing CI models for prediction of wave transmission past HIMMFPB. In the present work, five layer pipes with S / D of 2, 3, 4 and 5 are considered. The ANN model is developed for prediction of wave transmission for HIMMFPB. Two network models, ANN1 and ANN2 are constructed based on the parameters which influence the wave transmission of floating breakwater. The input parameters of ANN1 model areW / L , Hi / d and Hi / L . To study over a range of spacing of pipesiv S / D on Kt , an input parameter, S / D is added to form ANN2 model. Training and testing of the network models are carried out for different hidden nodes and epochs. It is observed that the correlation (above 90%) between predicted wave transmission values by the network models and measured values are in good agreement. Furthermore, to improve the result of prediction of wave transmission of HIMMFPB, recently developed technique such as SVMR is used. This technique works on structural risk minimization principle that has greater generalization ability and is superior to the empirical risk minimization principle as adopted in conventional neural network models. Support vector machines (SVMs) are based on statistical learning theory. The basic idea of support vector machines is to map the original data x into a feature space with high dimensionality through a non-linear mapping function and construct an optimal hyper-plane in new space. Six SVMR models are constructed using kernel functions. In order to study the performance of each kernel in predicting wave transmission of HIMMFPB, SVMR is trained by applying these kernel functions. Performance of SVMR is based on the best setting of SVMR and kernel parameters. Correlation Coefficient (CC) of SVMR (b-spline) model (CC Train = 0.9779 and CC Test = 0.9685) is considerably better than other SVMR models. However, it is noticed that ANN model in isolation cannot capture all data patterns easily. Adaptive neuro-fuzzy inference system (ANFIS) uses hybrid learning algorithm, which is more effective than the pure gradient decent approach used in ANN. ANFIS models are developed to predict wave transmission of HIMMFPB. The performance of the ANFIS models in the prediction of Kt is compared with the measured values using statistical measures, such as, CC, Root mean Square Error ( RMSE ) and Scatter Index ( SI ). All the ANFIS models have shown CCs higher than or equal to 0.9510, with RMSE less than or equal to 0.051074 and SI less than or equal to 0.102296. ANFIS5 model predictions are very realistic when compared with the measured values (CC Train = 0.9723, CC Test = 0.9635). It is also observed that an S D plays an important role to train ANFIS5 model to map an input-output relation. Furthermore influence of input parameters is assessed using Principalv Component Analysis (PCA). It is observed that Hi / L is the least influential parameter Based on the PCA study discarding the least influential parameters, ANFIS6 model is developed. It is observed that the ANFIS models yield higher CCs as compared to that of ANN models. To improve the performance of SVMR and better selection of SVMR and kernel parameters, hybrid genetic algorithm tuned support vector machine regression (GASVMR) model is developed to predict wave transmission through HIMMFPB. Furthermore, parameters of both linear and nonlinear SVM models are determined by GA. The results are compared with ANN, SVMR and ANFIS models in terms of CC, RMSE and SI . Performance of GA-SVMR is found to be reliably superior. CI models can be utilized to provide a fast and reliable solution in prediction of the wave transmission for HIMMFPB, thereby making GA-SVMR as an alternate approach to map the wave structure interactions of HIMMFPB.