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ETD at Indian Institute of Science (3.241 recursos)

Repository of Theses and Dissertations of Indian Institute of Science, Bangalore, India. The repository has been developed to capture, disseminate and preserve research theses of Indian Institute of Science.

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Mostrando recursos 1 - 20 de 77

  1. Towards Flexible Sensors and Actuators : Application Aspect of Piezoelectronic Thin Film

    Joshi, Sudeep
    Man’s desire to replicate/mimic the nature’s creation provided an impetus and inspiration to the rapid advancements and progress made in the sensors and actuators technology. A normal human being has five basic sensory organs, which helps and guides him in performing the routine tasks. This underlines the importance of basic sensory organs in a human life. In a similar fashion, sensors and actuators are of paramount importance for most of the science and engineering applications. The aim of the present thesis work is to explore the application of piezoelectric ZnO thin films deposited on a flexible substrate for the development...

  2. Polyvinylidene Fluoride Nasal Sensor : Design, Development and Its Biomedical Applications

    Roopa Manjunatha, G
    The growth of sensors and sensing technologies have made significant impact in our day-to-day life. The five principle sensory organs of our body should perform effectively, so that we can lead a good healthy life. Apart from these natural sensors, there are man-made sensors that helps us to cope with diseases, organ failure etc. and enable us to lead a normal life. In recent years, with the prevalence of new kind of diseases, the need for new type of biomedical sensors is becoming very important. As a result, sensors used for biomedical applications have become an emerging technology and rapidly...

  3. Growth of Semiconductor and Semiconducting Oxides Nanowires by Vacuum Evaporation Methods

    Rakesh Kumar, Rajaboina
    Recently, there has been a growing interest in semiconductor and semiconducting oxide nanowires for applications in electronics, energy conversion, energy storage and optoelectronic devices such as field effect transistors, solar cells, Li- ion batteries, gas sensors, light emitting diodes, field emission displays etc. Semiconductor and semiconducting oxide nanowires have been synthesized widely by different vapor transport methods. However, conditions like high growth temperature, low vacuum, carrier gases for the growth of nanowires, limit the applicability of the processes for the growth of nanowires on a large scale for different applications. In this thesis work, studies have been made on the...

  4. Studies on Multifrequensy Multifunction Electrical Impedance Tomography (MfMf-EIT) to Improve Bio-Impedance Imaging

    Bera, Tushar Kanti
    Electrical Impedance Tomography (EIT) is a non linear inverse problem in which the electrical conductivity or resistivity distribution across a closed domain of interest is reconstructed from the surface potentials measured at the domain boundary by injecting a constant sinusoidal current through an array of surface electrodes. Being a non-invasive, non-radiating, non-ionizing, portable and inexpensive methodology, EIT has been extensively studied in medical diagnosis, biomedical engineering, biotechnology, chemical engineering, industrial and process engineering, civil and material engineering, soil and rock science, electronic industry, defense field, nano-technology and many other fields of applied physics. The reconstructed image quality in EIT depends...

  5. Studies on Si15Te85-xGex and Ge15Te85-xAgx Amorphous Thin Films for Possible Applications in Phase Change Memories

    Lakshmi, K P
    Chalcogenide glasses are a class of covalent amorphous semiconductors with interesting properties. The presence of short-range order and the pinned Fermi level are the two important properties that make them suitable for many applications. With flash memory technology reaching the scaling limit as per Moore’s law, alternate materials and techniques are being researched at for realizing next generation non-volatile memories. Two such possibilities that are being looked at are Phase Change Memory (PCM) and Programmable Metallization Cell (PMC) both of which make use of chalcogenide materials. This thesis starts with a survey of the work done so far in realizing...

  6. Spatial Filtering Techniques for Large Penetration Depth and Volume Imaging in Fluorescence Microscopy

    Purnapatra, Subhajit Banergjee
    In the past two decades, Fluorescence microscopy has imparted tremendous impact in Biology and Imaging. Several super-resolution Fluorescence imaging techniques (e.g. PALM, STED, STORM, 4Pi and structured illumination) have enabled diff raction-unlimited imaging. But high resolution is limited to a depth of few tens of microns. Thus, deep tissue imaging and simultaneous volume imaging have become a highly sought after feature in Fluorescence microscopy. The research work in this thesis address these issues by using spatial filtering techniques to tailor the point spread function (PSF) which uniquely characterizes the optical sys-tem. The advantage of this approach lies in the fact that...

  7. Stochastic Dynamical Systems : New Schemes for Corrections of Linearization Errors and Dynamic Systems Identification

    Raveendran, Tara
    This thesis essentially deals with the development and numerical explorations of a few improved Monte Carlo filters for nonlinear dynamical systems with a view to estimating the associated states and parameters (i.e. the hidden states appearing in the system or process model) based on the available noisy partial observations. The hidden states are characterized, subject to modelling errors, by the weak solutions of the process model, which is typically in the form of a system of stochastic ordinary differential equations (SDEs). The unknown system parameters, when included as pseudo-states within the process model, are made to evolve as Wiener processes....

  8. Point-of-Care High-throughput Optofluidic Microscope for Quantitative Imaging Cytometry

    Jagannadh, Veerendra Kalyan
    Biological research and Clinical Diagnostics heavily rely on Optical Microscopy for analyzing properties of cells. The experimental protocol for con-ducting a microscopy based diagnostic test consists of several manual steps, like sample extraction, slide preparation and inspection. Recent advances in optical microscopy have predominantly focused on resolution enhancement. Whereas, the aspect of automating the manual steps and enhancing imaging throughput were relatively less explored. Cost-e ective automation of clinical microscopy would potentially enable the creation of diagnostic devices with a wide range of medical and biological applications. Further, automation plays an important role in enabling diagnostic testing in resource-limited settings....

  9. Design of a Vortex Tube based Refrigeration System

    Chatterjee, Aritra
    Vortex tube (VT) is a mechanical device with no moving parts. The fundamental principle of Vortex Tube is that it can split an incoming fluid flow of a constant pressure and constant temperature gas stream into two separate low pressure streams, one having higher enthalpy and the other having lower enthalpy than the inlet flow. So this device essentially works as a temperature separator. On separation from the device, a warmer flow exits through a terminal which is called the “hot end” and a low temperature stream comes out from another terminal known as the “cold end”. Just with a...

  10. Optimization of HfO2 Thin Films for Gate Dielectric Applications in 2-D Layered Materials

    Ganapathi, K Lakshmi
    Recently, high-κ materials have become the focus of research and been extensively utilized as the gate dielectric layer in aggressive scaled complementary metal-oxide-semiconductor (CMOS) technology. Hafnium dioxide (HfO2) is the most promising high-κ material because of its excellent chemical, thermal, mechanical and dielectric properties and also possesses good thermodynamic stability and better band offsets with silicon. Hence, HfO2 has already been used as gate dielectric in modern CMOS devices. For future technologies, it is very difficult to scale the silicon transistor gate length, so it is a necessary requirement of replacing the channel material from silicon to some high mobility material....

  11. Threshold Voltage Shift Compensating Circuits in Non-Crystalline Semiconductors for Large Area Sensor Actuator Interface

    Raghuraman, Mathangi
    Thin Film Transistors (TFTs) are widely used in large area electronics because they offer the advantage of low cost fabrication and wide substrate choice. TFTs have been conventionally used for switching applications in large area display arrays. But when it comes to designing a sensor actuator system on a flexible substrate comprising entirely of organic and inorganic TFTs, there are two main challenges – i) Fabrication of complementary TFT devices is difficult ii) TFTs have a drift in their threshold voltage (VT) on application of gate bias. Also currently there are no circuit simulators in the market which account for...

  12. Design, Development and Performance Analysis of Micromachined Sensors for Pressure and Flow Measurement

    Singh, Jaspreet
    Now-a-days sensors are not limited only to industry or research laboratories but have come to common man’s usage. From kids toys to house hold equipment like washing machine, microwave oven as well as in automobiles, a wide variety of sensors and actuators can be easily seen. The aim of the present thesis work is to discuss the design, development, fabrication and testing of miniaturized piezoresistive, absolute type, low pressure sensor and flow sensor. Detailed performance study of these sensors in different ambient conditions (including harsh environment such as radiation, temperature etc.) has been reported. Extensive study on designing of thin...

  13. Light Sheet Based Microfluidic Flow Cytometry Techniques for High throughput Interrogation and High-resolution Imaging

    Regmi, Raju
    Light allows to non-invasively study the complex and dynamic biological phenomenon undergoing within cells and tissues in their native state. The development of super-resolution microscopes in recent years has helped to overcome the fundamental limitation imposed by Abbe’s diffraction limit, thereby revolutionizing the field of molecular and cellular biology. With the advancement of various super-resolution techniques (like STED, PALM, and 4Pi) it is now possible to visualize the nanometeric cellular structures and their dynamics in real time. The limitations of existing fluorescence microscopy techniques are: poor axial resolution when compared to their lateral counterpart, and their inability to produce high...

  14. Mechanical, Structural, Thermal and Electrical Studies on Indium and Silver Doped Ge-Te Glasses having Possible PCM Applications

    Sreevidya Varma, G
    The Science behind amorphous Chalcogenide materials opened up new technologies in the arena of Phase Change Memories. The Ovonic universal phase change memory is called universal because it can replace flash memory, DRAM and SRAM. These are not only basic computer memory devices but also are becoming the driving force for the ongoing revolutionary growth of cell phones and other mobile devices, which are in desperate need of memory providing higher density, faster speed and lower power consumption. In this thesis, compositional dependence of various properties of different chalcogenide glasses are investigated, to explore the possibility of their application in...

  15. Numerical Investigation of Segmented Electrode Designs for the Cylindrical Ion Trap and the Orbitrap Mass Analyzers

    Sonalikar, Hrishikesh Shashikant
    This thesis is a numerical study of fields within ion traps having segmented electrodes1. The focus is on two cylindrical ion trap structures, two Orbit rap structures and one planar structure which mimics the field of the Orbit rap. In all these geometries, the segments which comprise the electrodes are easily Machin able rings and plates. By applying suitable potential to the different segments, the fields within these geometries are made to mimic the fields in the respective ideal structures. This thesis is divided into 6 chapters. Chapter 1 presents introduction and background information relevant to this work. A brief...

  16. Fabrication and Optimization of Yttria Stabilized Zirconia Thinfilms towards the Development of Electrochemical Gas Sensor

    Kiruba, M S
    Yttria stabilized Zirconia (8YSZ) is an extensively used solid electrolyte, which finds applications in electrochemical sensors, solid oxide fuel cells and gate oxide in MOSFETs. Recent studies report that YSZ thin films are better performers than their bulk counterparts, in terms of ionic conductivity even at moderate temperatures. YSZ thin films also attract attention with the scope of device miniaturization. However, most of the studies available in the literature on YSZ thin films focus mainly on their electrical characterization. In this work, YSZ thin films were deposited, characterized and possible use of sensors were evaluated. In the present work, 8...

  17. A Stochastic Search Approach to Inverse Problems

    Venugopal, Mamatha
    The focus of the thesis is on the development of a few stochastic search schemes for inverse problems and their applications in medical imaging. After the introduction in Chapter 1 that motivates and puts in perspective the work done in later chapters, the main body of the thesis may be viewed as composed of two parts: while the first part concerns the development of stochastic search algorithms for inverse problems (Chapters 2 and 3), the second part elucidates on the applicability of search schemes to inverse problems of interest in tomographic imaging (Chapters 4 and 5). The chapter-wise contributions of...

  18. Design, Development and Validation of Fiber Bragg Grating Sensor Based Devices for Detecting Certain Healthcare Parameters

    Chethana, K
    Several sensor technologies have been developed and experimented over the last few decades to cater various needs of medical diagnostics. Among these, fiber optic sensors, in particular, Fiber Bragg Grating (FBG) based sensors have attracted considerable attention due to their inherent advantages such electrical passiveness, immunity to Electro Magnetic Interference (EMI), chemical inertness, etc. The present research work focuses on design, development and validation of FBG sensor based devices for measurement of certain healthcare parameters in the context of foot function/gait cycle, cardiac and breathing activity, nostril dominance, hand grip/wrist angle force function, etc. The experimental work presented here emphasizes...

  19. Poly-Vinylidene Fluoride Based Vibration Spectrum Sensors and Energy Harvestors

    Nyayapati, Mahidhar Ramesh
    Mechanical vibrations in large structures such as buildings, bridges, dams and critical frequencies in large machinery generally have low frequencies (100Hz-1000Hz). To monitor large areas of such structures we need huge network of low cost, easily manufacturable, self-powered and stand-alone vibration spectrum sensors. The sensors should also consume very little power during their overall operation cycle and have moderately high frequency resoultion. The thesis provides mathematical analysis, design and development of stand-alone, low frequency vibration spectrum analyzer .A mechanically stretched polymer piezoelectric membrane, which has a fixed length and tension, can act as a single frequency detector due to its unique...

  20. Poly-Vinylidene Fluoride Based Vibration Spectrum Sensors and Energy Harvestors

    Nyayapati, Mahidhar Ramesh
    Mechanical vibrations in large structures such as buildings, bridges, dams and critical frequencies in large machinery generally have low frequencies (100Hz-1000Hz). To monitor large areas of such structures we need huge network of low cost, easily manufacturable, self-powered and stand-alone vibration spectrum sensors. The sensors should also consume very little power during their overall operation cycle and have moderately high frequency resoultion. The thesis provides mathematical analysis, design and development of stand-alone, low frequency vibration spectrum analyzer .A mechanically stretched polymer piezoelectric membrane, which has a fixed length and tension, can act as a single frequency detector due to its unique...

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