A study on thermal characteristics of polymer composites filled with micro sized tio2 particles

This thesis reports on the research dealing with the processing and characterization of TiO2 filled polymer composites. The first part of the work includes the description of the materials used and the details of the experiments that are done during this research. It also presents the test results in regard to the physical, mechanical and micro-structural characteristics of the epoxy and polypropylene composites filled with micro-sized TiO2 particles. The second part depicts the development of a theoretical heat conduction model based on which a mathematical correlation has been proposed for estimation of effective thermal conductivity of polymer composites with uniformly distributed micro-sized particulate fillers. In this part, the correlation is validated for TiO2 filled polymers through numerical analysis and experimentation. The last part has reported on the epoxy and polypropylene composites in regard to their other thermal characteristics such as glass transition temperature (Tg) and coefficient of thermal expansion (CTE). The effects of TiO2 content on these properties of epoxy and polypropylene have been studied experimentally. The estimation of effective thermal conductivity of the composites using finite element method (FEM) and using the proposed theoretical models is done and the results are validated by corresponding experimental results. The findings of this research suggest that incorporation of TiO2 into epoxy and polypropylene leads to substantial improvement in thermal conductivity and glass transition temperature of the resins. At the same time, TiO2 helps in lowering the coefficient of thermal expansion of such composites. This work further shows that the FEM serves as a good predictive tool for assessment of thermal conductivity of these composites. The theoretical correlation proposed in this work can serve as a very good empirical model for spherical inclusions to estimate the effective thermal conductivity of the composites within the percolation limit. With light weight and improved heat conduction capability, the TiO2 filled polymer composites can be used for applications such as electronic packaging, encapsulations, communication devices, thermal interface material, printed circuit board substrates etc

Computation of dynamic slices of aspect oriented programs

This thesis presents our work concerning computation of dynamic slicing of aspect oriented programs. Program slicing is a decomposition technique which extracts program elements related to a particular computation from a program. A program slice consists of those parts of a program that may directly or indirectly affect the values computed at some program point of interest, referred to as a slicing criterion. A program slice an be static or dynamic. Static slice contains all the statements that may affect the slicing criterion for every possible inputs to the program. Dynamic slice contains only those statements that actually affect the slicing criterion for a particular input to the program. Aspect-Oriented Programming is a new programming technique proposed for cleanly modularizing the cross- cutting structure of concerns. An aspect is an area of concern that cuts across the structure of a program. The main idea behind Aspect-Oriented Programming (AOP) is to allow a program to be constructed by describing each concern separately. Aspect J is an aspect-oriented extension to the Java programming language. Aspect J adds new concepts and associated constructs called join points, point cuts, advices, introductions, aspects to Java. We first store the statements executed for a particular execution in an execution trace le. Next, we develop a dependence-based representation alled Dynamic Aspect-Oriented Dependence Graph (DADG) as the intermediate program representation. The DADG is an arc-classied digraph which represents various dynamic dependences between the statements of an aspect-oriented program for a particular execution. Then, we present an efficient dynamic slicing technique for aspect-oriented programs using DADG. Taking any vertex as the starting point, our algorithm performs a graph traversal on the DADG using breadth-first graph traversal or depth-first graph traversal. Then, the traversed vertices are mapped to the original program to compute the dynamic slices. We have shown that our proposed algorithm efficiently calculates dynamic slices. The space complexity of the algorithm is O(S). The run-time complexity of the algorithm is O(S 2 ). We have also shown that our dynamic slicing algorithm computes correct dynamic slices

A study on thermal characteristics of polymer composites filled with micro sized tio2 particles

This thesis reports on the research dealing with the processing and characterization of TiO2 filled polymer composites. The first part of the work includes the description of the materials used and the details of the experiments that are done during this research. It also presents the test results in regard to the physical, mechanical and micro-structural characteristics of the epoxy and polypropylene composites filled with micro-sized TiO2 particles. The second part depicts the development of a theoretical heat conduction model based on which a mathematical correlation has been proposed for estimation of effective thermal conductivity of polymer composites with uniformly distributed micro-sized particulate fillers. In this part, the correlation is validated for TiO2 filled polymers through numerical analysis and experimentation. The last part has reported on the epoxy and polypropylene composites in regard to their other thermal characteristics such as glass transition temperature (Tg) and coefficient of thermal expansion (CTE). The effects of TiO2 content on these properties of epoxy and polypropylene have been studied experimentally. The estimation of effective thermal conductivity of the composites using finite element method (FEM) and using the proposed theoretical models is done and the results are validated by corresponding experimental results. The findings of this research suggest that incorporation of TiO2 into epoxy and polypropylene leads to substantial improvement in thermal conductivity and glass transition temperature of the resins. At the same time, TiO2 helps in lowering the coefficient of thermal expansion of such composites. This work further shows that the FEM serves as a good predictive tool for assessment of thermal conductivity of these composites. The theoretical correlation proposed in this work can serve as a very good empirical model for spherical inclusions to estimate the effective thermal conductivity of the composites within the percolation limit. With light weight and improved heat conduction capability, the TiO2 filled polymer composites can be used for applications such as electronic packaging, encapsulations, communication devices, thermal interface material, printed circuit board substrates etc

Parametric Comparison of K-means and Adaptive K-means Clustering Performance on Different Images

Image segmentation takes a major role to analyzing the area of interest in image processing. Many researchers have used different types of techniques to analyzing the image. One of the widely used techniques is K-means clustering. In this paper we use two algorithms K-means and the advance of K-means is called as adaptive K-means clustering. Both the algorithms are using in different types of image and got a successful result. By comparing the Time period, PSNR and RMSE value from the result of both algorithms we prove that the Adaptive K-means clustering algorithm gives a best result as compard to K-means clustering in image segmentation.   

THD Analysis of a Seven, Nine, and Eleven Level Cascaded H-Bridge Multilevel Inverter for Different Loads

A multilevel inverter is implemented for generating the required staircase AC voltage of output from various steps of voltages of DC sources. The multilevel inverter gives a better harmonic spectrum and a compatible quality of output. This article delves into an analytical analysis of the total harmonic distortion (THD) of different multilevel inverters which employ a multicarrier PWM technique. This technique is implemented for operating the switches at their respective angle of conduction. This paper deals with various cascaded H-Bridge multilevel inverters (CMI) with various loads that are modelled by implementing the MATLAB/Simulink platform. The output gives a better result of the proposed model in terms that it is helpful towards reducing the THD and the losses of switching

Equivalence of DES and AES Algorithm with Cellular Automata

In this paper we present the equivalence of the operations involved in DES and AES algorithm with operations of cellular automata. We identify all the permutation and substitution operations involved in DES and AES algorithm and compare these operations with the cellular automata rules. Then we find that permutation operations involved in DES and AES are equivalent to linear cellular automata rules providing diffusion property of cryptography whereas substitution operations involved in DES and AES are equivalent to non linear cellular automata rules providing the confusion property of cryptography. Hence instead of using operations involved in DES and AES algorithm, we can apply linear as well as non-linear cellular automata rules in cryptography for better security and parallel processing

Encryption and Decryption algorithm using two dimensional cellular automata rules in Cryptography

In this paper we present a new encryption and decryption algorithm for block cipher based on the linear (periodic boundary-PB) and nonlinear cellular automata rules. First we apply non linear CA rules (complements) to both plain text and key. Then PB CA rule is applied to the above results separately followed by the XOR operation of above results. After that the result of XOR operation is fed to substitution box(S-box) and again PB CA rules are applied followed by SBox. The decryption process is carried out just similar to that of encryption but in the reverse way. Both the process of encryption and decryption is performed for 8 number of rounds in order to avoid the dependency between the plain text and cipher text so that the our proposed algorithm is more secure than that of AES and DES algorithms

Neurotrophin receptor Ntrk2b function in the maintenance of dopamine and serotonin neurons in zebrafish

Neurotrophins and their receptors have highly conserved evolutionary lineage in vertebrates including zebrafish. The NTRK2 receptor has two isoforms in zebrafish, Ntrk2a and Ntrk2b. The spatio-temporal expression pattern of bdnf and ntrk2b in the zebrafish brain was studied using in situ hybridization. The robust and corresponding expression pattern of ntrk2b to bdnf suggests that ntrk2b is the key receptor for bdnf in the zebrafish brain, unlike its duplicate isoform ntrk2a. To study ntrk2b function, two different genetic strategies, the TILLING mutant and morpholino oligonucleotides (MO), were used. Specific subsets of the dopaminergic and serotonergic neuronal populations were affected in the mutants and morphants. The mutant showed anxiety-like behavior both in larval and adult stages. Our results consistently indicate that BDNF/NTRK2 signaling has a significant role in the development and maintenance of aminergic neuronal populations. Therefore, the ntrk2b-deficient zebrafish is well suited to study mechanisms relevant for psychiatric disorders attributed to a dysfunctional monoaminergic system.Peer reviewe

Performance of Used Transformer Oil as Dielectric Media During EDM of Inconel 718 Super Alloys

Application potential of used transformer oil as dielectric media has been experimentally studied during electro-discharge machining of Inconel 718 super alloys. Experiments have been conducted by varying peak discharge current and pulse-on duration; the following performance measures material removal efficiency, surface roughness, surface crack density and white layer thickness etc. have been studied. Improvement in EDM performance in purview of material removal rate, morphology and topography of the machined surface has been discussed while using used transformer oil (as dielectric) instead of kerosene. Topography of the EDMed surface has been analyzed in detail which has included surface roughness, metal migration, phase transformation, grain refinement, formation of intermetallic compounds, residual stress and micro-hardness. Overall, it has been included that application of used transformer oil has offered potential benefit as compared to kerosene dielectric media to facilitate machinability of ‘difficult-to-cut’ material Inconel 718 during electro-discharge machining