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Study on Probable Radionuclide Contents and Their Dose Assessment in Sand, Soil and Water Samples Collected from The Rupsha River, Khulna
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 101-108).The radionuclide contents and their activity concentrations in soil, sediment and water
samples collected from in and around of Rupsha River, Khulna, Bangladesh have been
determined by using a High Resolution Germanium detector (HPGe) of 20% relative
efficiency. A total of 44 samples of three categories were collected and analyzed. The activity
concentrations of 226Ra, 232Th and 40K in the soil samples of the Rupsha River side area have been found to be varied from 42.99 ± 8.60 to 53.92 ± 7.86 BqKg-1, 64.90 ± 6.60 to 94.16 ± 6.74 BqKg-1 and 581.02 ± 77.66 to 1098.50 ± 124.90 BqKg-1 respectively with an average
value of 50.16 ± 7.20 BqKg-1, 77.23 ±7.43 BqKg-1 and 864.63 ± 101.69 BqKg-1 respectively.
For sediment samples the activity concentrations of the corresponding radionuclides ranged
between 40.86 ± 4.31 to 58.27 ± 5.23 BqKg-1, 57.60 ± 6.84 to 82.78 ± 7.50 BqKg-1, 578.39 ±
74.62 to 1038.69 ± 110.70 BqKg-1 respectively with an average value of 50.46 ± 6.20 Bq/Kg,
73.99 ± 7.56 BqKg-1and 881.49 ± 100.25 BqKg-1 respectively. The results for both the soil
and sediment samples obtained for the corresponding nuclides are slightly higher than the
worldwide average values of 35, 30 and 400 BqKg-1. The activity contents of the water
samples did not show any evidence of enhancement. The calculated average absorbed dose
rates due to these radionuclides in soil and sediment samples have been found as 106.13
nGyh-1 and 105.03 nGyh-1, respectively which is higher than worldwide average values. The
estimated outdoor annual effective dose ranged from 0.11 to 0.14 mSvy-1 and 0.10 to 0.14
mSvy-1 with the mean values of 0.13 mSvy-1 and 0.13 mSvy-1 for soil and sediment samples,
respectively. The values of radium equivalent activity in almost all the samples were less than 370 BqKg-1. On the other hand, the values of external hazard index for soil and sediment samples varied between 0.52 to 0.67 and 0.49 to 0.67 with the average values of 0.61 and 0.61, respectively. The values are less than unity in all the samples that indicate the nonhazardous nature of the samples and there is no possibility of immediate health effect on the workers, public and environmentTuhina IslamMaster of Science in Physic
Numerical Electromagnetic Analysis of Lightning Surge Response on Vertical Conductor
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, May 2005.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 61-63).In analyzing the lightning performance of overhead power transmission lines and
substations, the lightning surge characteristics of transmission line components as well as
the statistical data of lightning such as the ground flash density and the stroke peak current
distributions are essential. Among the transmission line components, tower surge
characteristics including the tower footing impedance characteristics in the linear region
are probably the most fundamental factors since they contribute directly to the insulator
voltages during a lightning hit. Particularly for such tall structure as EHV or UHV doublecircuit
towers, the characteristics become more dominant owing to the longer round-trip
time of a travelling wave in the tower. An agreement on the interpretation of this
phenomenon, however, has not been reached yet.
There have been three considerations to evaluate the transient characteristics of a
tower as follows: (i) theoretical studies, (ii) simulation of reduced scale models and (iii)
simulation of full-sized tower. Measurement on full-sized towers is straightforward in
evaluating the actual characteristics of a tower struck by lightning, however it is difficult
to cam' out this kind of experiments in the ideal arrangement where a current lead wire is
stretched vertically above the tower top to simulate a lightning channel, owing to its scale.
Measurement on reduced scale models is more economical than full-sized towers, and is
flexible in setting up various experimental arrangements. It is however not easy to
maintain the accuracy. Theoretical studies on simplified geometry may be useful in
understanding the phenomenon, however, they are invalid for the accurate evaluation of
the dynamic electromagnetic behavior of a three dimensional (3-D) system struck by
lightning.
The simulation analysis of surge response are carried out in the several
arrangements of the current lead wire: (i) vertical and at the top of vertical conductor. (ii)
vertical and a little far from the top of vertical conductor. and (iii) horizontal and far from
the top of vertical conductor. In all the cases, the voltage measuring wire is placed at the
perpendicular to the current lead wire. Each of the arrangement of the current lead wire
affects the measured surge impedance of the vertical conductor and that has been
explained in this research in detail. If a travelling wave propagates along the vertical
conductor at the velocity of light, the reflected wave from the ground should return to the
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top of the vertical conductor just after the round-trip time of the travelling wave in the
vertical conductor.
For the accurate analysis of the dynamic electromagnetic field around a complex
tower system struck by lightning, electromagnetic modeling codes are appropriate. Of
many available codes, the Numerical Electromagnetic Code (NEC-2) based on the Method
of Moments is chosen for the present work, since it has been widely and successfully used
in analyzing thin-wire antennas and a tower system can be regarded as a thin-wire antenna.
In the present thesis, firstly, the applicability of NEC-2 to the electromagnetic field
analysis of vertical conductor surge response is verified by comparison with theoretical
results on simple structure.
Secondly, four parallel conductors model are taken into account for the analysis by
NEC-2 to evaluate the surge characteristics. Thirdly, the surge characteristics of actual
tower struck by lightning are studied with the help of NEC-2.
Finally, it can be concluded that this research presents some results concerning the
simulation of electromagnetic transient in transmission lines caused by direct and indirect
strikes of lightning, which will help to design the structure of tower and to design
lightning arrester to protect various electric appliances that is used in our everyday life.Md. Salah Uddin YusufMaster of Science in Electrical and Electronic Engineerin
Numerical Study of MHD Heat and Mass Transfer Flow Past an Infinite Vertical Porous Plate with Thermal Conductivity and Soret Effect in the Presence of Suction or Injection.
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 52-56).In the present study, numerical investigations have been performed to examine the MHD mixed
convection boundary layer flow over an impulsively started vertical permeable plate with
thermal-diffusion (Soret) and diffusion-thermo (Dufour) effects. Under some simplified
assumptions and using usual Boussinesq approximation, the governing boundary layer partial
differential equations have been transformed first into a non-dimensional system of non-linear
coupled partial differential equations by introducing suitable transformations. Secondly, the
transformed set of partial differential equations has been solved numerically using the implicit
finite difference numerical method. Numerical solutions are obtained for the velocity and
temperature fields as well as the concentration distribution for different values of the physical
parameters entering into the problem. The effects of these various involved parameters on the
velocity and temperature fields and on the concentration distribution have been investigated.
Finally, the obtained results involving the effects of these physical parameters on the flow
phenomena have been discussed with the help of graphs. The numerical results have shown that
the above mentioned effects have to be taken into consideration in the flow field and in the heat
and mass transfer process. It is also expected that the finding of this investigation may be useful
for the study of power engineering, geothermal and geophysical process.Md. Mahmudul HasanMaster of Science in Mathematic
Electro-oxidation of 1,2-dihydroxybenzene in Presence of Alanine, Phenylalanine and Leucine at Different pH Media
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, August 2016.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 159-163)The electro-oxidation of 1,2-dihydroxybenzene generates o-benzoquinone (Michael
acceptor) and its reaction in presence of different concentration of L-Alanine, LPhenylalanine and L-Leucine (nucleophiles) has been investigated. The overall study has been carried out in buffer solution of different pH (5, 7, 9 and 11) by using Cyclic
Voltammetry (CV), Controlled Potential Coulometry (CPC) and Differential Pulse
Voltammetry (DPV) techniques at different electrodes (GC, Pt and Au) and scan rates
(0.05-0.5 V/s). Cyclic voltammogram of electro-active 1,2-dihydroxybenzene in pure
buffer solution (5-11) shows one anodic and corresponding cathodic peak within a quasireversible process. Pure L-Alanine, L-Phenylalanine and L-Leucine are electro-inactive having no peak in the potential range of investigation (-0.6 to 0.9V).
Addition of different composition of L-Alanine (10-150 mM), L-Phenylalanine (2-100
mM) and L-Leucine (30-200 mM) in fixed 2 mM of 1,2-dihydroxybenzene solution, in the
second scan of potential a new anodic peak (A0) arises at the more negative potential with respect to the pure 1,2-dihydroxybenzene. The anodic (A1) and cathodic peak (C1) current intensity of 1,2-dihydroxybenzene also decreases significantly. This indicates the
participation of 1,4-Michael addition reaction of o-benzoquinone with L-Alanine, LPhenylalanine and L-Leucine to produce 2-((3,4-dihy droxyphenyl)amino)propanoic acid, 2-((3,4-dihydroxyphenyl)amino)-3-phenylpropanoic acid and 2-((3,4-dihydroxyphenyl) amino)-4-methyl-pentanoic acid adducts. The 1,4-Michael addition reaction of 1,2-dihydroxybenzene is strongly influenced by the concentration of nucleophiles. The electrooxidation of 2 mM 1,2-dihydroxybenzene is mostly favorable in 50 mM of L-Alaline, 20 mM of L-Phenylalanine and 100 mM of L-Leucine respectively.
The effect of pH on 1,2-dihydroxybenzene in presence of different nucleophiles has been
studied by varying pH ranging from 5 to 11. In acidic pH media (pH <7), no new anodic
peak arises after repetitive cycling due to protonation of amine group. But in the neutral
(pH=7) and basic media (pH >7), o-benzoquinone undergoes nucleophilic attack by the
amine part of amino acids and the maximum peak current is observed at pH 7. The slope value of 1,2-dihydroxybenzene-Alanine, 1,2-dihydroxybenzene-Phenylalanine and 1,2-dihydroxybenzene-Leucine adducts have been calculated (70.5 mV/pH for first anodic
peak A1), (59 mV/pH for first anodic peak A1) and (68.5 mV/pH for first anodic peak A1)
at 0.1 V/s respectively. These values indicate that the nucleophilic substitution reactions
are preceded via 1e−/1H+ process. It is also suggested that during the course of reaction, electron and proton are released simultaneously from the 1,2-dihydroxybenzene-Amino acid adducts. The nature of voltammogram, peak position and current intensity for the studied systems are different for different electrodes and the voltammetric response of GC electrode is better than Au and Pt electrodes.
The effect scan rates on cyclic voltammogram of 1,2-dihydroxybenzene in presence of LAlanine, L-Phenylalanine and L-Leucine have also been 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 with some chemical complications. The current function, Ip/v1/2 vs scan rates (v) of 1,2-dihydroxybenzene-Amino acid adducts are found to be decreased exponentially with increasing scan rate which suggests that the behavior of reaction mechanism is Electron transfer-Chemical reaction-Electron transfer (ECE) type for all the studied system. The products obtained by bulk electrolysis have also been analyzed by FTIR spectra.Palash Kumar DharMaster of Science in Chemistr
Simulation of Monsoon Rainfall 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, September 2017.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 91-93).In the present study, the Weather Research and Forecast (WRF-ARW V3.5.1) model have een
used to simulate the station wise monsoon rainfall during 2010–2014 over Bangladesh. The
initial and boundary conditions are drawn from the global operational analysis and forecast
products of National Center for Environmental Prediction (NCEP-GFS) available at 1°×1o
resolution. The model was configured in single domain, 6 km horizontal grid spacing with
161×183 grids in the east-west and north-south directions and 28 vertical levels. For the
simulation of monsoon rainfall WSM6-class graupel scheme coupled with Kain-Fritsch (KF)
cumulus parameterization (CP) scheme has been used. Initially the model was run 137 days for
long term prediction starting with the initial condition of 0000 UTC of 17 May up to 0000 UTC
of 1 October for the period 2010-2014. The model was also run 72 hours with every day 0000
UTC initial conditions for 124 days for the prediction of 24, 48 and 72 hours lead time rainfall in
the monsoon season of 2014. In this research convective and non-convective rainfall have been
simulated at 3 hourly interval then made daily and monthly total rainfall data for 24, 48, 72 hour
and long term during the studied period. We have compared this data with the observed rainfall
at 33 meteorological stations of BMD and TRMM rainfall. It has shown that the performance of the model for 24, 48 and 72 hours predictions are reasonably well except northeast and southeast hilly regions. The distribution of 24 hours lead time predicted rainfall is almost similar all over the country except the higher rainfall area where model simulated rainfall is much more. The prediction deteriorates as the prediction time increases. The long term predictions of simulated rainfall are not matched with BMD observed rainfall. The pattern of TRMM and observed rainfall are almost similar but the value of TRMM observations is much lower than that of observed rainfall. The RMSE shows that the value for 24 hour prediction lies within 15-30 mm range except hilly regions. The MAE shows that the value for 24 hour prediction lies within 10-20 mm range except hilly regions. It has also been observed that where the rainfall has minimum the RMSE and MAE have also minimum.Krishna HalderMaster of Science in Physic
Optimality Analysis of Maximin LHDs Obtaining by Iterated Local Search Heuristics Approach Regarding Audze-Eglais Criterion
No full textThis thesis is submitted in the partial fulfillment of the requirements for the degree of
Master of Philosophy in Mathematics.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 68-75).The design of experiments (DoEs) have much recent interest and this is likely to grow as more and more simulation models are used to carry out research. A good experimental design should have at least two important properties namely projective property (non-collapsing) and Space-filling (design points should be evenly spread over the entire design space) property. Any Latin Hyper-cube design (LHD) is inherently preserve projective property. But randomly generated LHDs have poor space-filling property. In consequence, in sense of space-filling, Optimal LHDs are required for good DoEs. Several optimal LHDs are available in the literature; Maximin LHD is one of the most frequently used among such optimal LHDs. It is also noted that researchers implement different type of methods to find out maximin LHDs. But the performances of the approaches are not same. In this study, we consider maximin LHDs obtained by Iterated Local search (ILS) heuristic approach in which inter-site distances are measured in Euclidean distance measure. We have compared the performance and effectiveness of ILS approach with some well-known approaches available in the literature regarding maximin LHDs in Euclidean distance measure. The experimental study agrees that ILS approach outperforms regarding maximin LHDs measured in Euclidean distance measure. We perform further extensive experiments in perspective of Audze-Eglais values. We compare Audze-Eglais values of maximin LHDs, which are optimized regarding ɸp optimal criterion and obtained by ILS approach, with Audze-Eglais value of Audze-Eglais LHDs, which are optimized regarding Audze-Eglais optimal criterion and obtained by Enhanced Stochastic Evolutionary (ESE) algorithm. In the experimental results show that the Audze-Eglais value of Maximin LHDs are comparable. We have also compared the performance of ILS approach with other approaches regarding various characteristics of the optimal designs by considering a typical design namely (k, N) = (4, 9). The comparison study reveals that ILS approach is one of the best approaches for finding maximin LHDs.Debasish BokshiMaster of Philosophy in Mathematic