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Surface Water Quality and its Impact on Water Supply Scenario in Khulna City of Bangladesh
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 2017.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 84-87)To get potable water is an acute problem now a days which is increasing in an alarming rate in southern region of Bangladesh. Khulna, the third largest city in Bangladesh, is located in the southwest of the country and has a population of 1.5 million. Ground water is the main source of supply water presently used by the Khulna Water Supply Authority, KWASA. Water supply for Citizens in Khulna has been suffering from limited access to water supply services. Out of approximately one and half million of population, only 17% has access to piped water supply, and the rest resorts to alternative sources, such as shared public taps and tube wells built privately. The present water supply in Khulna is mainly from ground water sources drawn from both deep and shallow tube wells. In the long term as demand increases, conjunctive use of ground water and surface water will be required, even though surface water may suffer from salinity intrusion in dry season. Due to increasing water demand in the city, the water supply system is vulnerable to supply required water to the people. Extensive abstraction of ground water from deep aquifer causes depletion of ground water level. Water in ground aquifer is not
replenishing at the same rate of abstraction. In future, it may not be possible to yield sufficient quantity of ground water necessary for Khulna city. Therefore, to cope with current insufficient supply and increasing demand of potable and domestic water, it is necessary to allocate alternate source instead of groundwater. Therefore, a comparative study of water quality for different rivers in and around Khulna city is necessary. The main objective of this study is to investigate the usability of surface water to reduce the vulnerability of ground water for the water supply system of Khulna City Corporation (KCC) area.
There are many rivers flow through south western zone into or nearby the Khulna city and meet with Bay of Bengal in southern part of Bangladesh. Those are the Vairab, Rupsha, Kobadak, Pashur, Mayur, Modhumoti etc. In this thesis, firstly the water quality parameters for four stations of Gorai- Modhumoti river system are presented. These stations are Station-1: Haridaspur (Kumar river), Station -2: Modhupur (Gorai-Modhumoti river), Station -3: Chapailghat (Modhumoti river) and Station -4: Mollarhat (Modhumoti river). After that the water quality parameters of Rupsha- Bhairab river system are presented. Among the water quality parameters turbidity, pH, TDS, EC, chloride, salinity etc. are tested in the laboratory. Mayur river has not been considered in this study due to its insufficient water flow and its upstream source is almost moribund. The water flow source of Mayur river is mainly KCC drainage waste water and rain water in rainy season. Recently, KWASA has selected the Mollahat Point of Modhumoti River as the intake point of raw water for the alternate water source to supply after treatment. In this study, the historical flow characteristics of Gorai-Modhumoti river is also studied to explain the sustainability of the raw water intake site for KWASA.
From comparison of water quality parameters, it is found that Modhumoti River contains very low amount of chloride concentration and salinity as compare to the other rivers. The salinity is found to be increasing from February and peak in April. Chapailghat, Modhupur and Haridaspur stations are found to have almost same salinity; highest is about 500 mg/l and lowest is 90 mg/l. Mollarhat contained lowest salinity among the four stations. All of stations contain higher salinity in summer due to lower discharge of river. For low discharge the sea water enter the downstream of river easily and contain higher salinity as compare to the upstream of the river. However, the salinity level is found to be increasing with years. At Mollarhat point of Gorai-Modhumoti river, the discharge is found to be varies nearly zero at winter season to about 4000 cumec in monsoon. The maximum discharge is found to be varied from 1500 to 4000 cumec per year. Annual minimum discharge is varied from zero to 85 cumec for different years. Very low discharges are observed in the years of 2009 to 2011. Like discharge, water level is found to be varied with seasons from nearly 1 m at winter season to about 8 m in monsoon. From the linear trend line it is observed that from an average maximum
water level of 8.23 m in 1995, it is decreasing by 0.056 m per year. Annual minimum water level is varied from 1.0 to 3.0 m for different years. Due to the dredging at the mouth of Gorai river in 2011, the water level is increased in 2012, which is again gradually decreased in the following years due to siltation at the mouth of Gorai. In the low water flow season, the average water flow rate in Modhumoti river was 25.5 m3/sec in 2015. The planned water intake volumes for Khulna City by KWASA are 110,000 m3/day (= 1.273 m3/ sec) in 2025 and 220,000 m3/day (= 2.546 m3/ sec) in 2030. Therefore, in low flow season the water will be drawn by a rate of 5.0% in 2025 and 10.0% in 2030. However, the feasibility study of KWASA assumed that safe
amount to intake water from the river is less than 5%.
Modhumoti River is mainly comes through Gorai river from Ganges. A small part comes from Arial khan River through upper Kumar river. In both the source rivers, the discharges are found in decreasing trend both in monsoon and winter. It is evident from the Gorai river discharge and dredging history at Gorai mouth that dredging effectively increases the flow in Gorai river, though huge siltation affect negatively afterwards. Therefore, to increase the discharge of Gorai river, it is necessary to keep dredging on a regular basis of Gorai River, which will maintain potential flow of Modhumoti River. In addition, Kumar river bed dredging to divert flow of Arial Khan river may help further to increase the flow in Modhumoti River. Flow Divider at Gorai Off-take can be installed to divert Ganges flow into Gorai-Modhumoti river.Md Kamal HossainMaster of Science in Civil Engineerin
Motor Imagery Movement and Neurological Disorder Classification using Salient Features of EEG Signal
No full textThis thesis is submitted to the Department of Biomedical
Engineering, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Biomedical
Engineering, July 2017.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 69-75).Electroencephalography (EEG) measurement plays a significant role in the clinical and
scientific research of brain studies. EEG signals are very important, particularly for
classification and treatment of neurological diseases and brain computer interface (BCI)
applications. The aim of this dissertation is to develop methods for the analysis and
classification of different categories of motor imagery (MI) movements, epileptic EEG
signals, and human alertness states. A novel method is also developed for continuous
alertness monitoring. EEG signals of MI movements are classified for right hand and left hand (two class) and right hand, left hand, and feet (three class) movements. Nowadays, MI is a highly prescribed method for the disabled patients to give them hope to control machine or computer by interfacing with brain or mind. This dissertation proposes a classification method between imagery left and right hands movement using Daubechies wavelet of discrete wavelet transform (DWT) and Levenberg-Marquardt back propagation training algorithm of artificial neural network (ANN). DWT decomposes the raw EEG data to extract significant features that provide feature vectors precisely. ANN classifies the two class and three class trials data. Classification accuracy varies with respect to the subject. This method can be used to design a well-organized BCI system with better accuracy. Results from classifier can be used to design brain machine interface (BMI) for better performance that requires high precision and accuracy scheme. Neurological disorder i.e. epilepsy detection is enough time consuming and requires thorough observation to determine epilepsy type and locate the responsible area of the cerebral cortex. The dissertation proposes an effortless epilepsy classification method for epilepsy detection and investigates the classification accuracy of multiclass EEG signal during epilepsy. For accomplishing the proposed research work we use DWT to obtain responsible features to accumulate feature vectors. Afterward feature vectors are given in the input layer of the ANN classifiers to differentiate normal, interictal, and ictal EEG periods. Accuracy rate is calculated based on the confusion matrix. Proposed method can be utilized to monitor and detect epilepsy type incorporating with an alarm system.
It is tiresome for human to concentrate constantly, though several works require continuous
alertness like efficient driving, learning, etc. A practical method is applied to investigate the
concentration state of human brain by EEG acquisition. This research work proposes
continuous alertness state classification method based on two different types of mental tasks
with respect to the resting state (resting with eyes open and eyes close). To conduct this
research work, some participants were involved and they performed several tasks such as
alphabet counting, virtual motor driving, resting with eyes open and eyes close. During the
performances of the tasks, 9 channel EEG data has been acquired from their scalps. The data
acquisition is performed by B-Alert (BIOPAC) system. The acquired data are filtered by IIR
filter and responsible channels are selected by the statistical method. The features of the
signals were extracted by using principal component analysis (PCA) and DWT algorithms.
The alert states of our brain are classified by ANN. In addition, the specific relative power
(RP) of the responsible frequency band of EEG signals is calculated for alertness monitoring.
Within the RP range of resting and active state, a threshold value is proposed for monitoring the alertness state of the participants. This work will be helpful to classify the epileptic states with more accuracy as well as this works is also a well guide to classify the motor imagery movements. In addition, the proposed method based on continuous alertness monitoring will be remarkable approach to design machines for monitoring driving or learning.Md. Mamun Or RashidMaster of Science in Biomedical Engineerin
Study of the Effect of Grain Structure and Phase Constitution on the Magnetic Properties of Nanocrystalline fe72.5cr1nb3cu1si13.5b9 alloy
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, March 2017.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 77-84).This thesis is based on the experimental investigation of the effect of grain size and phase constitution on the magnetic properties of nanocrystalline Fe72.5Cr1Nb3Cu1Si13.5B9 alloys in the amorphous and annealed states. The sample has been prepared by rapid solidification technique and their amorphous nature has been confirmed by X-ray diffraction (XRD). The crystallization behavior and the nanocrystal formation have been studied by Differential Thermal Analysis (DTA) and XRD. Magnetization measurements have been carried out using vibrating sample magnetometer (VSM). The ribbon sample has been annealed in a controlled way in the temperature range 450oC to 800oC for 30 minutes. DTA runs for the sample show
the existence of tow exothermic peaks one for and other for Fe2B phase. Thermal analysis experiment and from the obtained data activation energy of primary crystallization products phase is 3.26eV and secondary crystallization products for Fe2B is 4.87eV. The XRD experiments are in order to study the effect of structural parameters such as lattice parameter, grain size and silicon content of the nanocrystalline grain. In the optimized annealing condition the grain size has been obtained in the range of 10-30nm. The peak shift indicates the change of the values of Si-content of nanograins and therefore, the change of the values of lattice parameter of nanograins. The saturation magnetization (Ms) has been observed 122.6emu/gm and in as prepared condition Curie temperature (Tc) has been found to be 316oC, which quite close compared to the Tc of conventional FINEMET (i,e,
sample without Cr). The critical composition for disappearance of ferromagnetism fall
of curves Ms with the replacement Fe by Cr, where the nearest neighbor coupling to
longer dominant and intermediate range occurs and the magnetization process of this
amorphous ribbon sample are soft behavior of magnetic material.Md. Tahmid ShihabMaster of Science in Physic
Study on Morphological change and navigation Problems of Pussur River in Bangladesh
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 2017.Cataloged from PDF Version of Thesis.ussur River is situated in the south western hydrological zone of Bangladesh. Mongla
Port has established at the confluence of Pussur River and Mongla Nulla, approximately
71 nautical miles upstream from the Fairway buoy (approaches to the Pussur River) of the
Bay of Bengal. Mongla Port, the second gateway of Bangladesh was designed for an
average 8.5m draft ship. But after the construction of Jetties at Mongla Port, the depths in
several areas of Pussur Channel reduced significantly and regular maintenance dredging is
required to provide adequate depth alongside the berths, in the approaches to the berths
and in the Southern Anchorage areas. The objective of the study is to investigate the
temporal and spatial change of morphological behavior of Pussur River and to suggest
some engineering interventions for sustainable navigation in the Pussur channel. In this
study, bathymetric charts of Pussur River surveyed for different years (2005 to 2016) from
Chalna to Fairway buoy have been collected from Mongla Port Authority (MPA) and the
siltation/scouring rate and pattern of morphological change has identified through the
analysis. Some field studies are performed to collect some baseline primary data such as
tidal variation of water level, suspended sediment concentration and bed material
characteristics.
In the navigation route of Pussur river, the areal distance (straight) of Hiron Point to
Chalna is found as 55 km where the channel length is 91 km. The ratio of straight length to
channel length is found as 1:1.65, which implies that the channel is mildly meandering.
Based on MPA Hydrographic charts, it is observed that the width of the Pussur River
varies at different sections between 700 m to 3000 m and approach to Pussur is about 6000
m. The minimum depth is found to be varied from 1.4 m to 11.7 m below CD. It can be
noted that the lowest depth is found at upstream (Chalna) that gradually increases towards
downstream with the highest minimum depth at Mazhar Point to D’Suza Point and again
decreases at further downstream near Fairway Buoy. The maximum depth is found to be
varied from 7.5m to 29.6 m below CD from upstream to downstream, respectively. The
suspended sediment concentration in river water is measured for a sampling time of 13
hrs. At 0.8d depth, the concentration is found to be varied from 360 mg/l to 2096 mg/l in
flood tide which changes inversely with water level and velocity. At 0.2d depth, the
concentration varies from 154 mg/l to 1478 mg/l. Sieve analysis of bed material shows
that the Fineness Modulus (FM) of the collected 04 samples are 0.30, 0.60, 0.48 and 0.49,
i.e. the bed material is mostly sandy. From the average grain size distribution of bed
material, d50 is found as 0.052 mm.
It is observed that the MPA jetty area and its approaches are mildly scoured where the
upstream i.e Chalna to Digraj is being silted up. This upper segment is very shallow
having depth about 1 to 5 m CD and have a siltation rate of 0.22 to 0.95 m/year. From
2008 to 2013, there was a natural deepening near jetty front and approaches (scour rate
0.20 m/yr) due to increasing of ship movement and increase of fresh water flow from
upstream after Gorai river dredging. In 2014, jetty front of MPA was dredged upto 8.0 m
CD which has silted up by 1.0 m within one year. But at upstream of jetty no.9 i.e at front
of kleenheat LPG jetty, the channel scoured naturally about 1.5 to 2.0 m between 2008 to
2015. MPA vessel berth and wreck pavlina area hasn’t changed significantly after one
year of dredging. The vessel berth area has found to be scoured about 0.5 m and the
channel along wreck pavlina has silted about 0.25 m in west side and scoured about 0.75
m in east side in one year. The backfilling rate in mooring buoy dredging area has found
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very high. Near the danger khal the dredged area has filled up 1.5 m within one year. The
main reason of siltation here is creating a deep pocket where the surrounding areas are
shallower. The base creek area was dredged upto -5.2 m CD in the year 2014. After one
year of dredging the main navigation channel hasn’t changed significantly. But the East
side (Convex side) has deepened about 0.8 m naturally. The bed at Karamjol F.O area is
found to be naturally scoured more than 01 m in last 05 years. Similarly the sultan khal
area scoured more than 0.5 m in last 10 years. The food silo area has a mild siltation
pattern with a rate of 0.2 m/year.
The river reach from Joymonirgoal to Harbaria is quite stable in last few decades. The
navigation channel of this reach has sufficient draft for movement and anchoring upto 10.5
m draft vessel. This reach is the anchorage point of bulk cargo vessels. After Joymonirgol
the river has found very much stable and have sufficient draft for 10.50 m draft vessel upto
Hiron Point. After that, about 16 km river reach called outer bar between Hiron point to
Fairway Buoy is very critical and don’t have enough draft for more than 8.5 m draft
vessel. After the cyclone in 1988, the outer bar has been raised up to 0 to 2 m CD and
widening in the east-west direction and the trend is continuing until the recent year. At
fairway buoy channel has sufficient depth for mother vessels (20-25 m draft). From
fairway buoy to outer bar, this 16 km is quite stable in last few decades. At outer bar area
presently shipping channel is on the eastern side of wreck ocean wave. But this channel is
being silted up and the shallow portion is extending towards east side day by day. In the
downstream of buoy 14, the sedimentation rate at two points is found to be about 0.35
m/year. As a result the width of channel is also decreasing. However, in the west side of
wreck ocean wave, the channel is quite stable is last ten years and in degrading type.
From this study, it is found that capital dredging is required to get required draft for
navigation from Sabour Beacon to Rampal Power Plant as well as for outer bar area to
remove the sediment in the existing route or fix up a new route in the nearby area. The
total volume dredged in Pussur River over the period 1979 to 2016 is about 12.872 Mm3,
which is equivalent to an average of 3,47,000 m3 per year. Out of 37 years record, around
3.0 Mm3 dredging was done in the Jetty Front to maintain the berthing pocket alongside
the jetty. But after every dredging the re-siltation rate becoming very high and it’s
becoming a very big challenge for the existence of Port. Therefore, only dredging could
not sustain the channel effectively; Permanent measures such as structural interventions
are essential for long term improvement of navigability. To improve the berthing pocket
depth in front of the jetty, in addition to maintenance dredging, sheet piling could be
proposed as a solution. The rapid siltation rate in front of the jetty is due to the sliding of
the sediment from the jetty underneath. The main reason of siltation is low velocity of
flood and ebb flow. If the velocity of flow could be increased in vulnerable sections such
as MPA Jetty area and danger khal area, then the bed could be scoured naturally. Velocity
could be increased by contracting the channel using structural interventions. For the
canalization effect near the jetty area, spur dykes/groins/ guide bund opposite to jetty may
propose as a structural intervention. The deflected flow due to the structural intervention
in east bank may cause bank erosion at the upstream of the jetty area, a bank revetment
may propose to prevent this. For the canalization of the Mooring Buoy area, structural
measures can be proposed to close the western channel along the inner bar. For more
effective result, a bank revetment at the eastern bank, opposite to inner bar may be
required. However, these structural measures require in depth study to establish the
effectiveness.Motiur RahmanMaster of Science in Civil Engineerin
Analytical Solution of Quadratic Nonlinear Oscillator by Extended Iteration Method
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, August 2017.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 46-50).A modified approximate analytic solution of the quadratic nonlinear oscillator '' x+ x2 = 0''
has been obtained based on an Extended Iteration method. In this study the Fourier series
and utilized indispensable truncated terms have been used in each step of Extended
Iterations. The approximate frequencies obtained by this technique show a good agreement
with the exact frequency. The percentage of error between exact frequency and our third
approximate frequency is as low as 0.001%.There is no algebraic complexity in our
calculation that is why this technique is very easy. The results have been compared with
the exact results and other existing results that are convergent as well as consistent.Shajia Afrin FloraMaster of Science in Mathematic