KUET Institutional Repository (Khulna University of Engineering & Technology)
Not a member yet
1045 research outputs found
Sort by
InGaSb n-MOSFET: Modeling & Performance Analysis
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, December 2015.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 51-57).Antimonide-based III-V materials are highly interested in the channel of low power and high-speed
all-antimonide CMOS digital logic devices.
In this thesis work InGaSb-based double gate (DG) nMOSFET architectures with DG-nMOSFET
are proposed and numerically simulated. To assess and hence to compare the ballistic performance of
DG-JnMOSFET and, non-equilibrium greens function method is utilized under the framework of
well-known SILVACO’s ATLAS device simulation package without taking into account of
scattering. Wave function penetration to the oxide is taken into account in the simulation. In this
study the effect of gate length on drain current and other logic figures of merit like subthreshold
slope (SS), ION, IOFF, and ION/IOFF are investigated. The results obtained for DG-nMOSFET
demonstrate that there is negligible dependence on the “ON” current with the gate length. Small
increase in the OFF current is found for decreasing gate length from 15 nm to 13 nm, however, the
OFF current increases significantly when the gate length decreases from 13 nm. Subthreshold slope
decreases with increasing gate length. The maximum subthreshold swing is evaluated 80 mV/decade
for the gate length 7nm, which reduces to 70 mV/decade for the gate length 15 nm. Also the
threshold voltage decreases with decreasing gate length. Effect of the gate oxides (Al2O3 and HfO2)
in same equivalent oxide thickness (EOT) is also studied. The shift in threshold voltage and change
in ION/IOFF are found strong dependence with gate oxides having different dielectric constants.
Further, the effect of gate underlap is analyzed for the gate lengths 10nm and 15nm with different
underlap lengths. Drain current found to vary significantly for different underlap lengths when gate
length is 10nm. However, for the gate length 15 nm the variation of drain current is insignificant with
underlap length. The threshold voltage is also found to have strong dependence with gate length and
gate underlap length.Muhammad Shaffatul IslamMaster of Science in Electrical and Electronic Engineerin
Electrochemical Study Of Catechol In Presence Of Sulfanilic Acid And Diethytamine At Different Ph
No full textThis thesis is submitted to the Department of Departmentt of Chemistry, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Chemistry, December 2015.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 185-189).The electrochemical behavior of catechol in presence of diethylamide and sulfanilic acid &
catechol in presence of sulfanilic acid + diethylamide have been studied by cyclic
voltammetry, controlled potential coulometry, differential pulse voltammetry and
chronoamperometry techniques using Glassy carbon (GC), Gold (Au) and Platinum (Pt)
electrodes. The voltammetry studies have been carried out in variation of catechol,
diethylamine and sulfanilic acid concentration, buffer solution of different pH, different
electrodes and scan rate.
Upon addition of diethyl amine and sulfanilic acid in catechol solution at the second scan
of potential a new anodic peak appeared at the negative potential and the reduction peak
shifted with respect of pure catechol. Also the anodic and cathodic peak current decreases
significantly compared with the pure catechol that indicates the participation of reaction of
o-benzoquinone with diethylamine, sulfanilic acid and their mixtures. The products
generated from the reaction of catechol with diethylamine and sulfanilic acid are assumed
to be 4-(diethylamino)-benzene- I ,2-diol, and 4-(bis(3,4-dihydroxyphenyl)amino)
benzenesulfonic acid, respectively that undergo electron transfer at more negative
potentials than the catechol. The electro-synthesized products originated from catechol
with diethylamine and sulfanilic acid were isolated. The formation of new products was
also confirmed by FTIR spectra.
The effect of pH of catechol in presence of diethylamine and sulfanilic acid were studied
by varying pH from 3 to II except sulfanilic acid 2-9. For diethylamine, it is seen that at
pH 3-5, no new anodic peak appeared after repetitive cycling. In the pH 7-1 1, the o-
benzoquinone undergoes nucleophilic attack by the amines that voltammetric new anodic
peak A0 appeared after repetitive cycling. In contrast, for sulfanilic acid at pH 9 no new
anodic peak appeared after repetitive cycling. Whereas in pH 7, the voltammogram shows
a small peak. For diethylamine, the maximum peak current is obtained at pH 7 but the
maximum peak current of sulfanilic acid is obtained at pH 3. The slopes of the peak
potential, E vs pH plot was determined graphically as the anodic peaks of catecholdiethylamine
(69 mV/pH for first anodic peak A1mV/pH for appeared peak Ao) and catechol-sulfanilic acid (36 mV/pH for first anodic peak A1 or 38 mV/pH for appeared peak Ao) at 0.1 V/s. This indicates that the oxidation reaction of catechol-diethylamine adduct proceeded via the 1e71H process whereas catechol-sulfanilic acid adduct proceeded via the 2ei2H processes. This also suggests that during the reaction not only electron but also proton are released from the catechol-amine adduct.
The reaction was strongly influenced by the pH as well as concentration of diethylamine
and sulfanilic acid. The reaction was mostly favorable in 250 mM of diethylamine with
fixed 2 mM of catechol at pH 7. The reaction of catechol in presence of sulfanilic acid was
favorable in 2 mM sulfanilic acid, 2 mM catechol at pH 3. The electro-oxidation of
catechol-diethylamine adduct are facilitated in neutral media whereas catechol-sulfanilic
acid in acid media.
The scan rate effect on cyclic voltammogram of catechol in presence of diethylamine and
sulfanilic acid were also studied. The peak current of both the anodic and the
corresponding cathodic peaks increases with the increase of scan rate. The nearly
proportionality of the anodic and corresponding cathodic peak suggests that the peak
current of the reactant at each redox reaction is controlled by diffusion process. The
current function for anodic peak A0, (I/v) of catechol-diethylamine derivative was found
to be decreased exponentially with increasing scan rate. Catechol-diethylamine derivatives
have been found to undergo electrochemical reaction with ECE (electron transferchemical
reaction- electron transfer) type mechanism. But, the current function for the anodic peak A0,
(I1,/v) of catechol-sulfanilic acid derivative was found to be decreased with increasing scan rate and such a behavior is adopted as indicative of an ECECE type
mechanism.Md. AIim UddinMaster of Science in Chemistr
Synthesis and Characterization of MgFe204 Ferrite Nanoensemble for Biomedical Application
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 Philosophy in Physics, Septmber 2015.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 122-136).Magnetic nanoparticles have drawn tremendous attraction from both
fundamental aspect as well as applications in biomedicine such as magnetic bio-separation, detection of biological entities, magnetic resonance imaging, magnetic
fluid hyperthermia and targeted drug delivery due to their fascinating magnetic
properties. Superparamagnetic nanoparticles have become the focus of this study
because their superparamagnetic, biocompatible and hydrophilic properties would be
revealed after modifying the particle surface by suitable surfactants. Considerable
research in this area has provided valuable in sites; however, suitable magnetic
materials that can be fulfill all the requirements of MRI and hyperthermia applications
are still under investigation. This thesis reports on an investigation into the synthesis, control, and stabilization of high quality magnesium ferrite nanoparticles for biomedical
application. A new understanding of the factors effecting nanoparticle growth in a coprecipitation methodology has been determined. Then the ferrimagnetic MgFe204
r nanoparticles were modified by annealed temperature from 200 to 1400°C using box
furnace. The crystal structural, mean particle size and magnetic properties of the
modified ferrimagnetic MgFe204 nanoparticles were measured to investigate the
effect of each process on the synthesized nanoparticles. The structural, morphological,
magnetic properties of these synthesized products were characterized by using X-ray
diffraction (XRD), Vibrating sample magnetometer (VSM), Mössbauer spectroscopy
and NMR analysis. XRD patterns of as-dried powder yielded single phase. No impurity peaks were detected. With the increase of annealing temperature, the width of peaks decreases which reflects the coarsening of particles. The smallest crystallite size about 3 nm was obtained for as-dried sample while the largest value 71.86 nm was obtained from the highest studied temperature 1400°C. The crystallite size of the nanoparticles abruptly increased with the annealing temperature. Magnetization measurements have been accomplished by VSM. It was found that saturation magnetization increases with the increase particle size. The small particles first exhibit superparamagnetic behavior at
the early stage and then transform to ferromagnetic behavior when particle size passes
the superparamagnetic limit. Interesting experimental results on the size dependent
magnetic properties at different temperatures have been found. Other structural and
magnetic properties such as chemical isomer shift, quadruple splitting and hyperfine
IL field were determined by Mössbauer spectroscopy. Superparamagnetic/ferromagnetic
transition with the increase of particle size has also confirmed by this analysis.
Mössbauer spectroscopy measurements are shown to evidence collective inter-particle
correlations between the nanoparticles. The magnesium ferrite nanoparticles were
then coated with biocompatible Chitosan (CS) and Polyethylene glycol (PEG). NMR
spectroscopy was studied to investigate the spin-spin or T2 relaxivity values to
determine its applicability in magnetic resonance images as MRI contrast agents.Nipa DebnathMaster of Philosophy in Physic
Study on the Effect of Hydrometeors on the Track and Intensity of Tropical Cyclone using 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 Philosophy in Physics,December 2015.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 116-121).In this research microphysical and cumulus parameterization schemes on Weather
Research and Forecasting (WRF-ARW core) model have been used to study the effects of hydrometeors on the prediction of track and intensity of tropical cyclones Mala (2006),
Sidr (2007) and Phailin (2013) which formed over the Bay of Bengal and hit Myanmar,
Bangladesh and eastern coast of India respectively. The hydrometeors are cloud water, rain water, graupel, snow, ice and water vapor mixing ratio. The initial and boundary conditions are drawn from the global operational analysis and forecast products of National Center for Environmental Prediction (NCEP-GFS) available for the public at 1°×1° resolution. The model was run by using Kessler, Lin et al., WSM 3-class simple ice, Ferrier (New Eta), WSM 6-class graupel and Thomson graupel microphysics (MP) coupling with different cumulus parameterization (CP) schemes. The CP schemes used to simulate the Tropical Cyclone are Kain-Fritsch (KF) and Betts-Miller-Janjic (BMJ). The model domain consists of 8-24°N and 77-96°E and has 12 km horizontal resolution with 28 vertical sigma levels. The model was run for 96 and 72-h using initial data at 0000 UTC of 26 and 27 April 2006 for TC Mala, at 0000 UTC of 8 and 9 October 2013 for TC Phailin and at 0000 UTC of 11 and 12 November 2007 for TC Sidr. In order to examine the effect of hydrometeors on the movement of tropical cyclones space-averaged vertical profiles of water vapor, cloud water, rain water, graupel, snow, ice mixing ratio (g kg-1 ), vorticity and relative humidity have been calculated once every three hours. For the analysis of effects of cloud hydrometeors the model domain has been divided into 5 different regions. The different regions are Dl (22oN-26oN and 87°E-93oE), D2 (18oN-22°N and 81oE-87°E), D3 (14oN- 18°N and 78-84°E), D4 (12oN-22oN and 84cE-94°E) and D5 (17°N-22°N and 94oE-97°E). The tracks and intensity are compared with those provided by the operational centers like JTWC and IMD. The simulated result suggests that the hydrometeors and vorticity have impact on the track of tropical cyclones. The amount of hydrometeors are started to increase 2 to 3 days before
in a direction where the tropical cyclone moves. In all combination of MP and CP the area
and time average of water vapor mixing ratio (g/kg) provides similar results. Water vapor
mixing ratio has not change significantly during the period of movement of tropical
cyclones.Md: Jakir HossainMaster of Philosophy in Physic
Studies on the Extension of Shelf life of Selected Type of Mangos
No full textThis thesis is submitted to the Department of Chemistry, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Chemistry, November 2015.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 70-75).The application of different types of cost effective preservatives such as
tetracycline, sodium benzoate, acetic acid and glycerine at various concentrations
for the extension of, shelf lives of Himsagar and Langra mangoes were studied.
The physical characters such as appearance, colour, flavour, taste and texture of'
treated mango were more attractive than those of control one. The shelf life of,
treated mango was prolonged significantly as conipared to that of control one. The
weight loss control capacity of preservatives treated mangoes was higher than that
from control at 500 ppm of' tetracycline, 80 ppm of sodium benzoate and 100 ppm
of acetic acid for Himsagar mango and 10 ppm of tetracycline, 100 ppm of
sodium benzoate and 100 ppm of acetic acid lhr I angra cultivar. The superior
treatment tetracycline 500 ppm, sodium benzoate 80 ppm and acetic acid 100 ppm
of Himsagar cultivar reduced the physiological loss in weight 15.79% to 33.62%
with respect to control at 7th day. But at 8th day, the treatments, tetracycline 500
ppm, sodi urn benzoate 80 ppm and acetic acid 100 ppm reduced the physiological
loss in weight 35.34% to 40.33% with respect to control mango. On the other hand
the superior treatments tetracycline 10 ppm, sodium benioate 100 ppm and acetic
acid 100 ppm of Langra mango reduced the physiological loss in weight 17.31% to
29.23% with respect to control at 9thday. The treatments, tetracycline 10 ppm sodium
benzoate 100 ppm and acetic acid 100 ppm reduced the physiological loss
in weight 31.65 % to 41.53% with respect to control mango, cultivar of' Langra at
the 9th day. The efficiency of' glycerine as preservative of Himsagar and Langra
mango was not more effective than the other preservatives. The nutritional qualities
of mango were also affected remarkably after treatment with preservatives. At the
last edible stage, chemical analysis of mango pulp of preservatives treated
Himsagar mango at tetracycline 500 ppm, sodium benzoate 80 ppm and acetic
acid 100 ppm showed higher pH(5.56, 5.73 and 5.22), TSS (15%, 16% and
18%), total sugar (22.24, 23.53 and 23.30 g/100g), iron (6.7327, 2.5959 and
1.6789 mg/100g), vitamin C ( 20.05. 21.61 and 20.35 mg/100g) and protein
(1 .53%, 0.60% and 2.90%) in comparison to control mango (pH 5.19, TSS =
100%, total sugar = 18.60 g/l 00g, iron = 0.7218 mg/I 00g, vitamin C 19.20
mg/100g and protein = 0.57%). The treatments, tetracycline 10 ppm, sodium
benzoate 100 ppm and acetic acid 100 ppm showed higher pH (5.19, 5.21 and
5.25), TSS (16%. 14% and 17%), total sugar (11.31, 12.42 and 11.38 g/100g),
iron (3.3852, 3.3079 and 4.9801 mg/100g), vitamin C (17.32, 17.81 and 18.09
mg/100g) and protein (2.35%. 3.22% and 1.85%) for cultivar of Langra in
comparison to control mango (pH 5.19. TSS = 10%, total sugar 9.04 g/loog,
iron = 0.7118 mg/100g, vitamin C = 16.21 mg/l00g and protein = 0.55%). In
comparison to control mango it is evident that the preservatives treated mangoes
might be in superior quality as it contains higher vitamins, total soluble solids.
total sugar. protein. iron and pH than those of control.Md. Mizanur MurshedMaster of Philosophy in Chemistr
Approximate Solution of the Quadratic Nonlinear Oscillator by Iteration Procedure
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, December 2015.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 28-34).An analytical technique has been developed based on an iteration method to determine higher order approximate periodic solutions for a nonlinear oscillator with discontinuity for which the elastic force term anti-symmetric and quadratic. Usually, a set of nonlinear algebraic equations is solved with this method. However, analytical solutions of these algebraic equations are not always possible, especially in the case of large oscillations. A modified approximate analytic solution of the quadratic nonlinear oscillator "ẍ + x2 sgn(x) = 0" has been obtained based on an iteration procedure. Here we have used the truncated Fourier series in each iterative step. The approximate frequencies obtained by the technique shows a good agreement with the exact frequency and periodic solutions with the exact ones. The percentage of error between exact frequency and fourth approximate frequency of the method is as low as 0.00003%.The method is mainly illustrated by the quadratic nonlinear oscillator but it is also useful for many other nonlinear problems.Md. Rakib HossainMaster of Science in Mathematic
Studies on the Application of Antibiotics as External Preservatives of Mango Cultivar of Fazli
No full textThis thesis is submitted to the Department of Chemistry, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Chemistry, June 2015.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 58-63).The application of various antibiotics at different concentrations (10, 20, 30, 40, 50, 60, 70, 80, 90 and 100 ppm) for the extension of storage life and quality of fazli mango was studied. The physical properties such as appearance, colour, flavor, taste and texture of all antibiotics treated mangoes were more attractive than those of control one. The storage life of treated mango was prolonged significantly as compared to that of control one. The weight loss control capacity of antibiotics treated mango at 20 ppm of etracycline, amoxicillin 50 ppm, co-trimoxazole 20 and 30 ppm, cefradine 50 ppm, zithromycin 20 ppm was higher than that from control mango. The superior treatment tetracycline 20 ppm, co-trymoxazole 20 & 30 ppm and cefradin 50 ppm reduced the physiological loss in weight 15.79% to 33.62% with respect to control at 14th day. But at 15th day the treatments tetracycline 20 ppm, co-trymoxazole 20 ppm and cefradin 50 ppm reduced the physiological loss in weight 29.34% to 34.33% with respect to control mango. The nutritional qualities of mango were also affected remarkably after treatment with antibiotics. At the last edible stage chemical analysis of mango pulp from antibiotics treated mango at tetracycline 20 ppm, amoxicillin 50 ppm, co-trymoxazole 20 and
30 ppm, ciprofloxacin 20 ppm, cefradin 30 ppm, azithrornycin 20 ppm, cefixime 20 and 30 ppm showed higher pH (5.25, 5.25, 6.20, 6.25, 6.15, 6.32, 5.65, 6.31 and 5.24), total soluble solids (TSS) (12.0%, 11.5%, 15.0%, 19.0%, 18.5%, 17.0%, 15.0%, 14.0% and 13.5%), total sugar (9.79, 6.59, 8.96, 9.77, 11.53, 9.99, 12.39, 9.80 and 10.32 g/100g), protein (0.79%, 1.03%, 0.38%, 0.54%, 0.49%, 0.39%, 0.46%, 0.60% and 0.50%), and iron ( 0.9344, 1.0529, 0.4602, 0.6204, 0.4010, 0.7858, 1.2985, 0.6909 and 0.7572 mg/100g) in comparison to control mango (pH = 5.19, TSS = 10%, total sugar = 10.9 g/l00g, protein = 0.57% and iron = 0.7218 mg/100g). In comparison to control mango it is evident that the antibiotic treated mangoes might be in superior quality as it contains higher vitamin A, vitamin C, total soluble solids, total sugar, iron (Fe) and pH than those of control one.Md. Arifuzzaman KhondokarMaster of Philosophy in Chemistr