KUET Institutional Repository (Khulna University of Engineering & Technology)
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Effect of Temperature on Bond Strength of Reinforced Concrete Structure
No full textThis thesis is submitted to the Department of Civil Engineering, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Civil Engineering, April 2016.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 84-88)The study has been carried out to investigate the influence of temperature on bond behavior of reinforced concrete. The effects of casting temperature and curing temperature on various properties of concrete were investigated. Four different temperatures (20 oC, 30 oC, 45 oC and 60 oC) were maintained for this purpose. Locally available materials were used to prepare the specimens. To observe the effect of coating on bond stress, three different types of coating were used in this work such as red oxide, synthetic enamel paint and aluminum oxide. The study also investigates the temperature effect on corrosion of reinforced concrete. In this work, pullout test and electrochemical corrosion were performed as a major test program. To carry out these tests, 100 mm dia and 200 mm high cylindrical concretes were prepared. A 12 mm
dia MS bar was placed vertically at the center concrete layer. Bond stress measurement under different temperatures and coatings were the major findings of this work. Test results explained that volume of void increased with the increment of temperature. Result of bond strength showed 20% better performance for lower casting and curing temperature compared to higher temperature. Application of coating on rebar surface did not give satisfactory result of bond stress compared to non-coated rebar. 20 oC temperature induced specimens increase the time of corrosion crack initiation and decrease the penetration rate than 60oC temperature induced specimens. Coatings significantly showed a good agreements for corrosion effect on reinforced concrete. Among three coatings, aluminum oxide revealed better performance against pullout
test and electrochemical corrosion test. Finally, it can be concluded that temperature at 20 oC gives significant bond stress and provides better protection for corrosion than 60 oC temperature.Bappa Kumar PaulMaster of Science in Civil Engineerin
Analytical Solutions of Second Order Strongly Nonlinear Differential Systems with Slowly Varying Coefficients
No full textThis thesis is submitted to the Department of Mathematics, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Mathematics, June 2016.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 26-30).Considerable attention has been directed toward the study of strongly nonlinear
differential systems. Nonlinear differential systems have been widely used in many areas
of applied mathematics, physics, plasma and laser physics and engineering and are of
significant importance in mechanical and structural dynamics for the comprehensive
understanding and accurate prediction of motion.
The aim of the present study is to develop an analytical technique for obtaining the
approximate solutions of second order strongly nonlinear differential systems with slowly
varying coefficients and higher order nonlinearity in presence of small damping based on
the He’s homotopy perturbation method (HPM) and the extended form of the Krylov-
Bogoliubov- Mitropolskii (KBM) method. Graphical representation of any physical
system is important for its locations, amplitudes and phases. So the results obtained by
the presented method are compared with those solutions obtained by the fourth order
Runge-Kutta method in graphically.Chumki Rani DeyMaster of Science in Mathematic
A Study of Structural and Magnetic Properties of Mg-Cu Mixed Spinel Ferrites
No full textThis thesis is submitted to the Department of Physics, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Physics, April 2016.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 111-120).Cataloged from PDF Version of Thesis.Mg-Cu ferrites are well-known technological magnetic materials finding applications in various electrical devices. The present work is focused on the influence of substitutions and sintering temperature on structural and magnetic properties of Mg-Cu ferrites. Mg1- xCuxFe2O4 where x=0.0, 0.1, 0.2, 0.3, 0.4 and 0.5 samples have been prepared by conventional ceramic method, sintered at 1100°C, 1200°C and 1200°C (quenched). Some physical properties such as lattice parameters, density, porosity, magnetic properties such specific magnetization and hyperfine magnetic field. The structural phase identification was carried out by X-ray diffraction (XRD), microstructure analysis of the samples following scanning electron microscope (SEM), specific magnetization measurement by vibrating sample magnetometer (VSM) and Mössbauer spectroscopy analysis. The X-ray diffraction
analysis revealed that all the samples are crystallize in single phase cubic spinel structure. It was found that lattice parameter and porosity decreases with the Cucontent. It was observed from the microstructure study that the grain size increase with the increasing Cu-content. Thoughout the investigation it has also been found that grain size increases with increasing sintering temperature. Magnetization measurements have been accomplished by VSM. It was found that saturation magnetization increases with Cu-content with high value of 36.77 emu/gm for x = 0.5 at sintered temperature 1200°C (quenched), as well as microstructure grain size increases and grain growth clear visible. Interesting experimental results on
magnetization at different sintering temperature have been found. Other structural and
magnetic properties such as chemical isomer shift, quadruple splitting and hyperfine
field were determined by Mössbauer spectroscopy. The velocity scale of a thin 57Fe
sample and the isomer shifts are given relative to the centroid of the spectrum. The
shifts of Fe atoms in all Mg-Cu ferrites sample behave trivalent ions. The spectrum
for the Mg1-xCuxFe2O4 ferrites consists of six lines which are broad as compared with
Mössbauer spectrum of a pure 57Fe samples. One of the magnetic signals is a sextet
typical of those associated with a good ferromagnetic at room temperature. In a
ferromagnetic order all Fe with antiparallel behavior is consistent with a diluted
exchange coupling between magnetic Fe-ions on the tetrahedral site to octahedral site.Apurba PodderMaster of Science in Physic
Sensitivity study for the simulation of Tornado/Nor’wester during pre-monsoon season over Bangladesh using high resolution WRF-ARW model
No full textThis thesis is submitted to the Department of Physics, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Physics, August 2016.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 121-127).Comprehensive sensitivity analyses on physical parameterization schemes of Weather Research and Forecasting (WRF-ARW V3.5.1) Model have been carried out for the simulation of squall/nor'wester on 07 April 2012, 28 April 2012, 27 April 2014 and 15 May 2014 over Bangladesh. Final Reanalysis (FNL) data (l° x l°) from National Centre for Environment Prediction (NCEP), is used as initial and lateral boundary conditions which is updated at six hourly interval i.e. the model is initialized with 0000, 0600, 1200 and 1800 UTC initial fields of corresponding dates. The NCFP FNL data is interpolated to the model horizontal and vertical grids. The model is configured in a single domain, having 3 km horizontal grid spacing with 173x225 grids in the east-west and north-south directions and 15 vertical levels. By using Grads software, the different meteorological parameters, stability indices and energies are obtained, which are related to Nor'wester/squall line. The six different MP schemes used in this research are Kessler, Lin et al., WSM6, Thompson, SBU and WDM6. The meteorological parameters, which have been analyzed, are Wind Speed at 10m Level, Temperature at 2m Level, Sea Level Pressure (SLP), Relative Humidity (RH), Maximum Reflectivity, Latent Heat, MCAPE, MCIN, Total Total Index ('IT), Vertical Total Index (VT). Cross Total Index (CT), K Index (KI), Lifting Condensation Level (LCI.) and Level of Free Convection (LFC) at Dhaka, Chittagong, Sylhet, Khulna and Barisal stations. Significant changes are found by all the MPs coupling with CPs in all the parameters during the time of occurrence of squall/gusty wind. Significant changes are found in all the parameters for all MPs coupling with CPs at Dhaka after 0500 UTC and at Chittagong after 0900 UTC of 7 April 2012, which is delayed almost one and half hours. BMJ has simulated reflectivity at a particular time but KF simulated reflectivity wide range of time over Dhaka and Chittagong on 7 April 2012. Significant changes are found by all the MPs coupling with CPs in all the parameters during the time of occurrence of squall at Barisal and Chittagong on 15 May 2014.Busrat JahanMaster of Science in Physic
New Analytical Methods for Finding Optimal Solution of a Transportation Problems
No full textThis thesis is submitted to the Department of Mathematics, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Philosophy in Mathematics, January 2016.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 31-34).Determining the efficient solution for large scale of transportation problems (TPs) is an important task in operations research. TPs can also be formulated as a linear programming problem (LPP). The TP is concerned for finding an optimal distribution plan for a single commodity from several sources to different destinations. A given supply of the commodity is available at the different number of sources and there is a specified demand for the commodity at each of the various numbers of destinations and the unit transportation cost between each source-destination pair is known. In the simplest case, the unit transportation cost is constant during the period. In this thesis, a modified Vogel's approximation method has been developed for obtaining a good primal solution of a large scale of TPs. Also, a direct analytical method has been developed for finding an optimal solution for a wide range of transportation problems. Numerical illustrations are considered and the optimality tests of the results are justified by these methods. The most attractive feature of these methods is that they require very simple arithmetical and logical calculations. So, it is very easy to understand and use for layman. These methods will be very worthwhile for those decision makers who are dealing with logistics and supply chain related issues. One can easily adopt the proposed methods among the existing methods for simplicity of the presented method.Rijwana KawserMaster of Philosophy in Mathematic
Numerical Investigation of Stress Field for Anisotropic Elastic Bonded Joints
No full textThis thesis is submitted to the Department of Mechanical Engineering, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Mechanical Engineering, March 2016.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 52-55)In recent years, intelligent or smart structures and systems have drawn more and more
attention. Bonded structures are playing a key role as active components in many fields of engineering and technology. Mechanical stress occurs in smart structures for mechanical or thermal loading. The stress concentrations caused by mechanical or thermal loads may lead to crack initiation and extension, and sometimes the stress concentrations may be high enough to debond the material parts. Reliable service lifetime predictions of bonded components demand a complete understanding of the debonding processes of these materials. The stress fields are one of the main factors responsible for debonding under mechanical or thermal loading. Stress singularity frequently occurs at a vertex in an interface of joints due to discontinuity of materials. Stress singularity is related to debonding and delamination at interface of the bonded joints. Different numerical methods had developed for determining the stress field in a 3D dissimilar material joint. Several studies have investigated the stress field in 3D elastic materials. Recently, some researchers proposed the solution of singular stress field and its stress intensity factors of an interfacial corner of a 2D dissimilar anisotropic material joint with crack. However, the stress field at a vertex in 3D anisotropic elastic bonded joints has not been made clear. In this study, the stress field at a vertex and interface edge has been investigated in anisotropic bonded joints.
The project was focused on the reliability of anisotropic elastic bonded joints under
varying tensile load condition. In the present work, the displacement and stress
distributions at the vertex and along the interface edge of the joint were determined using
Autodesk Simulation Mechanical 2015 software. The activities of the project involve the
use of advanced numerical techniques based on Finite Element Method (FEM). The stress field in anisotropic elastic bonded joints with different materials condition was calculated. The stress and displacement field near the vertex and interface edge was investigated using developed model and material combination. Finally, the numerical results were analyzed. The numerical results suggest that the displacement and stress distribution at the vertex and interface edge were larger than the inner portion of the joints. Therefore there is a possibility of delamination and debonding occurs near the vertex and free edge of the interface of bonded joint due to higher stress concentration.A. H. M. Abdullah Al MamunMaster of Science in Mechanical Engineerin
Service Aware Fuzzy Logic Based Handover Decision in Heterogeneous Wireless Networks
No full textThis thesis is submitted to the Department of Electrical and Electronic Engineering, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Electrical and Electronic Engineering, November 2016Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 55-57).The ubiquitous services of wireless communication networks are growing rapidly by the
development of wireless communication technologies. While a user is roaming from one cell
to another cell, an intelligent decision mechanism and network selection is extremely crucial
to maintain the quality of service (QoS) during handover. Handover decision must be made
preciously to avoid any unnecessary phenomenon like ping-pong, corner effect, call blocking,
and call dropping etc. In addition, the handover decision must be very efficient and costeffective.
Particular services require diverse level of QoS and different networks provide
different level of service in terms of throughput, mobility, jitter, security, price, etc. This
work considered service types like voice, video, and data and their QoS requirements for
handover decision using fuzzy logic in heterogeneous network environment. Service is an
important factor for the users and particular service requires respective QoS. This research
provides all the cases of handover decisions between macrocell and femtocell networks
considering service type. The proposed system models regarding these handover decisions
using fuzzy logic, considering several input parameters e.g. received signal strength indicator
(RSSI), data rate, user’s velocity, and interference level (signal-to-noise plus interference
ratio) are shown. All handover cases in macrocell/femtocell integrated network such as femtocell to macrocell, macrocell to femtocell or femtocell to femtocell are addressed in this
research. The performance of different parameters are shown based on service type are
analyzed.Mehek-Moutushy Rahman MouMaster of Science in Electrical and Electronic Engineerin