Non-Destructive Evaluation of Ion-Implanted Semiconductor Thin Films Using Photothermal Deflections Spectroscopy

Materials and equipment which fail to achieve the design requirements or projected life due to undetected defects may require expensive repair or early replacement. Such defects may also be the cause of unsafe conditions or catastrophic unexpected failure, and will lead to loss of revenue due to plant shutdown. Non-Destructive Evaluation (NDE) / Non Destructive Testing (NDT) is used for the examination of materials and components without changing or destroying their usefulness. NDT can be applied to each stage of a system’s construction, to monitor the integrity of the system or structure throughout its life.

Photothermal beam deflection for non-destructive evaluation of semiconductor thin films

Non-destructive testing (NDT) is the use of non-invasive techniques to determine the integrity of a material, component, or structure. Engineers and scientists use NDT in a variety of applications, including medical imaging, materials analysis, and process control.Photothermal beam deflection technique is one of the most promising NDT technologies. Tremendous R&D effort has been made for improving the efficiency and simplicity of this technique. It is a popular technique because it can probe surfaces irrespective of the size of the sample and its surroundings. This technique has been used to characterize several semiconductor materials, because of its non-destructive and non-contact evaluation strategy. Its application further extends to analysis of wide variety of materials. Instrumentation of a NDT technique is very crucial for any material analysis. Chapter two explores the various excitation sources, source modulation techniques, detection and signal processing schemes currently practised. The features of the experimental arrangement including the steps for alignment, automation, data acquisition and data analysis are explained giving due importance to details.Theoretical studies form the backbone of photothermal techniques. The outcome of a theoretical work is the foundation of an application.The reliability of the theoretical model developed and used is proven from the studies done on crystalline.The technique is applied for analysis of transport properties such as thermal diffusivity, mobility, surface recombination velocity and minority carrier life time of the material and thermal imaging of solar cell absorber layer materials like CuInS2, CuInSe2 and SnS thin films.analysis of In2S3 thin films, which are used as buffer layer material in solar cells. The various influences of film composition, chlorine and silver incorporation in this material is brought out from the measurement of transport properties and analysis of sub band gap levels.The application of photothermal deflection technique for characterization of solar cells is a relatively new area that requires considerable attention.The application of photothermal deflection technique for characterization of solar cells is a relatively new area that requires considerable attention. Chapter six thus elucidates the theoretical aspects of application of photothermal techniques for solar cell analysis. The experimental design and method for determination of solar cell efficiency, optimum load resistance and series resistance with results from the analysis of CuInS2/In2S3 based solar cell forms the skeleton of this chapter.

Non-destructive evaluation of photovoltaic materials and solar cells using Photoluminescence

Photoluminescence (PL) spectroscopy is an optical technique that has emerged successful in the field of semiconductor material and device characterization. This technique is quite a powerful one which gives idea about the defect levels in a material, the band gap of the material, composition as well as material quality. Over the recent years it has received an elevation as a mainstream characterization technique. This thesis is an attempt to characterize each individual layer used in a thin film solar cell with special focus on the electrical properties. This will be highly beneficial from the lab as well as industrial point of view because electrical measurements generally are contact mode measurements which tend to damage the surface. As far as a thin film solar cell is concerned, the constituent layers are the transparent conducting oxide (TCO), absorber layer, buffer layer and top electrode contact. Each layer has a specific role to play and the performance of a solar cell is decided and limited by the quality of each individual layer. Various aspects of PL spectroscopy have been employed for studying compound semiconductor thin films [deposited using chemical spray pyrolysis (CSP)] proposed for solar cell application. This thesis has been structured in to seven chapters

Non-destructive evaluation of carrier transport properties in CuInS2 and CuInSe2 thin films using photothermal deflection technique

Photothermal deflection technique (PTD) is a non-destructive tool for measuring the temperature distribution in and around a sample, due to various non-radiative decay processes occurring within the material. This tool was used to measure the carrier transport properties of CuInS2 and CuInSe2 thin films. Films with thickness <1 μm were prepared with different Cu/In ratios to vary the electrical properties. The surface recombination velocity was least for Cu-rich films (5×105 cm/s for CuInS2, 1×103 cm/s for CuInSe2), while stoichiometric films exhibited high mobility (0.6 cm2/V s for CuInS2, 32 cm2/V s for CuInSe2) and high minority carrier lifetime (0.35 μs for CuInS2, 12 μs for CuInSe2

An Evaluation of Extension Activities in the Development of Aquaculture in Kerala

Aquaculture is one of the prime catalysts for the socio-economic development of Indian economy contributing to the nations food and nutritional security, export earnings, income and employment generation. In this study an evaluation of extension activities in the development of aquaculture in Kerala. This study was conducted with a view to examine how the Kerala fisheries department offered extension services to the aquaculture farmers in the freshwater and brackish water sectors of the state through various agencies like Fish Farmers Development Agency(FFDA), Brackish water Fish Farmers Development Agency (BFFDA). In this study there are 3 category of respondent’s fresh water beneficiary farmers, brackish water beneficiary farmers and fisheries extension officers. The main motive of the thesis is to make an attempt to explore the responses of local producers to the extension programs of the state with special reference to the aquaculture sector of Kerala, India. The most important technical constraint faced by the fresh water farmers was lack of knowledge followed by non-availability of quality seeds. In the case of brackish water farming, it was infection of disease followed by lack of knowledge. The overall activities of the department of fisheries were ‘fairly good’. It indicate the need for improvements in the delivery of extension services to various target groups. The state fisheries department has already moving towards evolving these modes of extension activities by community participation.

Geochemistry of transition, non-transition and rare-earth elements in the surficial sediments of continental shelf of Kerala and an annex to the Cochin estuarine system

The metals present in the surface sediments have high demand on a global perspective, and the main reservoir of these elements is believed to be the ocean floor. A lot of studies on metals are going on throughout the world for its quantification and exploitation. Even though, some preliminary attempts have been made in selected areas for the quantitative study of metals in the western continental shelf of India, no comprehensive work has been reported so far. The importance of this study also lies on the fact that there has not been a proper evaluation of the impact of the Great Tsunami of 2004 on the coastal areas of the south India. In View of this, an attempt has been made to address the seasonal distribution, behavior and mechanisms which control the deposition of metals in the sediments of the western continental shelf and Cochin Estuary, an annex to this coastal marine region.Surface sediment samples were collected seasonally from two subenvironemnts of southwest coast of India, (continental shelf of Kerala and Cochin estuarine system), to estimate the seasonal distribution and geochemical behavior of non-transition, transition, rare-earth elements, Th and U. Bottom water samples were also taken from each station, and analysed for temperature, salinity and dissolved oxygen, hence the response of redox sensitive elements to oxygen minimum zone can be addressed. In addition, other sedimentary parameters such as sand, silt, clay fractions, CaCO3 and organic carbon content were also estimated to evaluate the control factors on level of metals present in the sediment. The study used different environmental data analysis techniques to evaluate the distribution and behavior of elements during different seasons. This includes environmental parameters such as elemental normalisation, enrichment factor, element excess, cerium and europium anomalies and authigenic uranium.

Studies on Non-Resonant Multiphoton Processes in Atomic Hydrogen

In the present thesis we have formulated the Dalgarno-Lewis procedure for two-and three-photon processes and an elegant alternate expressions are derived. Starting from a brief review on various multiphoton processes we have discussed the difficulties coming in the perturbative treatment of multiphoton processes. A small discussion on various available methods for studying multiphoton processes are presented in chapter 2. These theoretical treatments mainly concentrate on the evaluation of the higher order matrix elements coming in the perturbation theory. In chapter 3 we have described the use of Dalgarno-Lewis procedure and its implimentation on second order matrix elements. The analytical expressions for twophoton transition amplitude, two-photon ionization cross section, dipole dynamic polarizability and Kramers-Heiseberg are obtained in a unified manner. Fourth chapter is an extension of the implicit summation technique presented in chapter 3. We have clearly mentioned the advantage of our method, especially the analytical continuation of the relevant expressions suited for various values of radiation frequency which is also used for efficient numerical analysis. A possible extension of the work is to study various multiphoton processcs from the stark shifted first excited states of hydrogen atom. We can also extend this procedure for studying multiphoton processes in alkali atoms as well as Rydberg atoms. Also, instead of going for analytical expressions, one can try a complete numerical evaluation of the higher order matrix elements using this procedure.

Development and Evaluation of Blind Identification Techniques for Nonlinear Systems

Identification and Control of Non‐linear dynamical systems are challenging problems to the control engineers.The topic is equally relevant in communication,weather prediction ,bio medical systems and even in social systems,where nonlinearity is an integral part of the system behavior.Most of the real world systems are nonlinear in nature and wide applications are there for nonlinear system identification/modeling.The basic approach in analyzing the nonlinear systems is to build a model from known behavior manifest in the form of system output.The problem of modeling boils down to computing a suitably parameterized model,representing the process.The parameters of the model are adjusted to optimize a performanace function,based on error between the given process output and identified process/model output.While the linear system identification is well established with many classical approaches,most of those methods cannot be directly applied for nonlinear system identification.The problem becomes more complex if the system is completely unknown but only the output time series is available.Blind recognition problem is the direct consequence of such a situation.The thesis concentrates on such problems.Capability of Artificial Neural Networks to approximate many nonlinear input-output maps makes it predominantly suitable for building a function for the identification of nonlinear systems,where only the time series is available.The literature is rich with a variety of algorithms to train the Neural Network model.A comprehensive study of the computation of the model parameters,using the different algorithms and the comparison among them to choose the best technique is still a demanding requirement from practical system designers,which is not available in a concise form in the literature.The thesis is thus an attempt to develop and evaluate some of the well known algorithms and propose some new techniques,in the context of Blind recognition of nonlinear systems.It also attempts to establish the relative merits and demerits of the different approaches.comprehensiveness is achieved in utilizing the benefits of well known evaluation techniques from statistics. The study concludes by providing the results of implementation of the currently available and modified versions and newly introduced techniques for nonlinear blind system modeling followed by a comparison of their performance.It is expected that,such comprehensive study and the comparison process can be of great relevance in many fields including chemical,electrical,biological,financial and weather data analysis.Further the results reported would be of immense help for practical system designers and analysts in selecting the most appropriate method based on the goodness of the model for the particular context.

Phytochemical investigations on ‘black glumed’ Njavara (Oryza sativa L.), the medicinal rice, as compared to staple varieties and evaluation of their antioxidant, anti-inflammatory and anticancer effects

The study was planned to investigate the bioactive compounds in Njavara compared to staple varieties and their bioactivity to substantiate the medicinal properties. Results of the study on chemical indices, antioxidant activity and antiinflammatory activity (in vivo) of Njavara black rice bran and rice in comparison with non-medicinal varieties like Sujatha and Palakkadan Matta rice bran and rice are given. The phytochemical investigation and quantification of Njavara extracts in comparison with staple varieties are detailed in this study. The last chapter is divided in three sections (A, B and C). Section A comprises the antioxidant activity by in vitro assays like DPPH, superoxide anion radical and hydrogen peroxide scavenging activity of the compounds. Also, theoretical studies using DFT were carried out based on DPPH radical scavenging activity for understanding the radical stability and mechanism of antioxidant activity. Section B comprises the anti-inflammatory activity of the identified compounds namely tricin and two flavonolignans in both in vivo and in vitro models. Section C describes the cytotoxicity of the rare flavonolignans, tricin 4’-O-(erythro-β-guaiacylglyceryl) ether and tricin 4’-O-(threo-β-guaiacylglyceryl) ether towards multiple cancer cells belonging to colon, ovarian and breast tumours.

Evaluation of the Power Consumption of Routing Protocols for Wireless Sensor Networks

Sensor networks are one of the fastest growing areas in broad of a packet is in transit at any one time. In GBR, each node in the network can look at itsneighbors wireless ad hoc networking (? Eld. A sensor node, typically'hop count (depth) and use this to decide which node to forward contains signal-processing circuits, micro-controllers and a the packet on to. If the nodes' power level drops below a wireless transmitter/receiver antenna. Energy saving is one certain level it will increase the depth to discourage trafiE of the critical issue for sensor networks since most sensors are equipped with non-rechargeable batteries that have limitedlifetime. Routing schemes are used to transfer data collectedby sensor nodes to base stations. In the literature many routing protocols for wireless sensor networks are suggested. In this work, four routing protocols for wireless sensor networks viz Flooding, Gossiping, GBR and LEACH have been simulated using TinyOS and their power consumption is studied using PowerTOSSIM. A realization of these protocols has beencarried out using Mica2 Motes.

Evaluation of the Power Consumption of Routing Protocols for Wireless Sensor Networks

Sensor networks are one of the fastest growing areas in broad of a packet is in transit at any one time. In GBR, each node in the network can look at itsneighbors wireless ad hoc networking (? Eld. A sensor node, typically'hop count (depth) and use this to decide which node to forward contains signal-processing circuits, micro-controllers and a the packet on to. If the nodes' power level drops below a wireless transmitter/receiver antenna. Energy saving is one certain level it will increase the depth to discourage trafiE of the critical issue forfor sensor networks since most sensors are equipped with non-rechargeable batteries that have limited lifetime.

Evaluation of the Power Consumption of Routing Protocols for Wireless Sensor Networks

Sensor networks are one of the fastest growing areas in broadwireless ad hoc networking (?Eld. A sensor node, typically'contains signal-processing circuits, micro-controllers and awireless transmitter/receiver antenna. Energy saving is oneof the critical issue for sensor networks since most sensorsare equipped with non-rechargeable batteries that have limited lifetime.In thiswork, four routing protocols for wireless sensor networks vizFlooding, Gossiping, GBR and LEACH have been simulated using Tiny OS and their power consumption is studied usingcaorwreiredTOoSuStIuMs.ingAMirceaal2izMaotitoens.of these protocols has been carried out using mica 2 motes

A Study on Non Performing Assets of Public Sector Banks in India with Special Reference to State Bank of Travancore

The reforms in Indian banking sector since 1991 is deliberated mostly in terms of the significant measures that were implemented in order to develop a more vibrant, healthy, stable and efficient banking sector in India. The effect of a highly regulated banking environment on asset quality, productivity and performance of banks necessitated the reform process and resulted the incorporation of prudential norms for income recognition, asset classification and provisioning and capital adequacy norms, in line with international best practices. The improvements in asset quality and a reduction in non-performing assets were the primary objective enunciated in the reform measures. In this context, the present research critically evaluates the trend in movement of nonperforming assets of public sector banks in India during the period 2000-01 to 2011-12, thereby facilitates an evaluation of the effectiveness of NPA management in the post-millennium period. The non-performing assets is not a function of loan/advance alone, but is influenced by other bank performance indicators and also by the macroeconomic variables. In addition to explaining the trend in the movement of NPA, this research also explained the moderating and mediating role of various bank performance and macroeconomic indicators on incidence of NPA

Marine yeast Candida MCCF 101 as feed supplement in aquaculture: nutritional quality, optimization of large scale production and evaluation of its protective effect on Koi carp from Aeromonas infection

Marine yeast have been regarded as safe and showing a beneficial impact on biotechnological process. It provides better nutritional and dietary values indicating their potential application as feed supplements in aquaculture. Brown et al. (1996) evaluated all the marine yeasts characterised with high protein content, carbohydrate, good amino acid composition and high levels of saturated fats. However, there is paucity of information on marine yeasts as feed supplements and no feed formulation has been found either in literature or in market supplemented with them. This statement supported by Zhenming et al. (2006) reported still a lack of feed composed of single cell protein (SCP) from marine yeasts with high content of protein and other nutrients. Recent research has shown that marine yeasts also have highly potential uses in food, feed, medical and biofuel industries as well as marine biotechnology (Chi et al., 2009; 2010). Sajeevan et al. (2006; 2009a) and Sarlin and Philip (2011) demonstrates that the marine yeasts Candida sake served as a high quality, inexpensive nutrient source and it had proven immunostimulatory properties for cultured shrimps. This strain has been made part of the culture collection of National Centre for Aquatic Animal Health, Cochin University of Science and Technology as Candida MCCF 101. Over the years marine yeasts have been gaining increased attention in animal feed industry due to their nutritional value and immune boosting property.Therefore, the present study was undertaken, and focused on the nutritional quality, optimization of large scale production and evaluation of its protective effect on Koi carp from Aeromonas infection