KUET Institutional Repository (Khulna University of Engineering & Technology)
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Approximate Analytic Solutions of the Nonlinear Cubic Oscillator by Iterative 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, November 2016.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 42-46).A modified approximate analytic solution of the cubic nonlinear oscillator “ẍ + x3 = 0" has been obtained based on an iteration method. Here we have used the truncated Fourier series in each iterative step. The approximate frequencies obtained by this technique show a good agreement with the exact frequency. The percentage of error between exact frequency and our fifth approximate frequency is as low as 0.009%. The calculation with this technique is very easy. The modified technique accelerates the rapid convergence of the solution, reduces the error solution and increases the validity range.Md. Mominur RahmanMaster of Science in Mathematic
Study of Stimulation Effects on Different Bands of EEG Signal
No full textThis thesis is submitted to the Department of Biomedical Engineering (BME), Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Masters of Science in Biomedical Engineering, September, 2016.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 49-52).Brain–computer interfaces (BCIs) are the communication bridge between the human brain and a computer which may be implemented on the basis of steady-state evoked potentials (SSEPs). A brain–computer interface is a direct communication pathway between the brain and an external device. BCIs are often directed at assisting, augmenting, or repairing human cognitive or sensory-motor functions. The field of BCI research and development has since focused primarily on neuroprosthetics applications that aim at restoring damaged hearing, sight and movement. The objectives of the research is to check the different stimulation effects of human brain, to improve the accuracy, higher information transfer rate (ITR), desired bandwidth (BW), and signal to noise ratio (SNR) of BCIs and to identify Power and Energy of different Stimulation Effects on Alpha and Beta bands of EEG signal. In this research the power and energy of Alpha and Beta bands of EEG signal for different stimulation were determined and signal analysis, signal processing, Fast Fourier Transform (FFT), Statistical parameter methods were used. The performance of stimulator depends on many factors such as size and shape of stimulator, frequency of stimulation, luminance, color, and subject attention. Information Transfer Rate (ITR) varies with the change of frequency and size of the visual stimuli. In this research, a circular repetitive visual stimulator (CRVS) of different diameter (2", 2.5"and 3"), color (RGB), frequency (10, 15 and 20 Hz) was used. When the size of the stimulator changes from 2" to 2.5" a greater increase of Alpha wave (58.18%) is observed than Beta wave (13.68%). But a further increase in size from 2" to 2.5" a greater decrease of Alpha wave (45%) is observed than Beta wave (36.59%).Tarun Kanti GhoshMasters of Science in Biomedical Engineering
Air Quality Modeling and Health Risk Assessment of Air Pollutants Generating from Khulna Power Plant
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, May 2016.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 75-82)Clean air is seriously affected by the atmospheric emissions generating from industrial
sectors. Power plants contribute significantly among these emissions of air pollutants.
This study describes the air pollutants emission from Khulna Power Company Limited
(KPCL), the distribution of emitted pollutants with time and space, the contribution of
power plant emission to the ambient air, and finally the estimation of health risk.
This Study reveals that KPCL (225 MW power generation capacity) using Heavy Fuel
Oil (HFO) that contains C (83.42%), H (10.02%), S (0.7%), O (0.05%) and N (0.1%) by
weight and the chemical formula of HFO was derived as C2230H3211S7N2.5O. The energy content of HFO was determined 17.76 MJ/kg and it contains Amino (-NH), Hydroxyl (-OH) and Aliphatic Carbon (-CH), Esters (S-OR) and Sulphate (S=O) bonds. The atmospheric emission from KPCL Power plants was estimated as 197.4 t/yr of SO2, 84 t/yr of NOX, 9 t/yr of CO, 12.46 t/yr of PM10, 9.30 t/yr of PM2.5 and 2.7 kg/yr of Lead
compounds. The dominant air pollutants from KPCL were found SO2 (62.04%) and NOx
(26.35%).
This study also shows that the dispersion of air pollutants from KPCL during September
month mostly travelled towards the northern direction in a long distance (>300 km)
covering the area of Jessore, Chuadanga, magura, Jhenaidah in Khulna division; Pabna, Shirazgonj, Bogra in Rajshahi division and in some cases dispersed over Dinazpur, Rangpur, Thakurgaon in Rangpur division. During the period of November 2014 to February 2015 the plume travelled long distance of more than 200km covering the area of Mongla, Bagerhat Shundarbans, Potuakhali, Borguna, Gopalgonj, Pirozpur and over Bay of Bengal. Plume also travel over Sundarbans about one- fourth (4 months) period of a year. Back trajectory of long range transport showed that air pollutants from India, Bhutan and Nepal were also contributed to the airshed of Khulna city. Due to the location Himalayan Mountains the massive air pollution of china seems not transported to Khulna airshed.
Air Quality Index (AQI) results showed that during the September 2013the AQI for SO2
(15) and NOX (21) indicating the ‘good’ category (1-50) which pose little or no short term
health risk. During this month comparing with the available local air quality monitoring
station data, it was found that 18.5% of total ambient SO2 and 12.36% of total ambient
NOX contributed by KPCL emission respectively. From dispersion modeling of
November 2014 to February 2015, it was found that, 2km surrounding area of KPCL is
mostly affected by SO2 and NOX. Average concentrations of SO2in that area were
7.04μg/m3 in November 2104, 7.7μg/m3 in December 2014, 6.62μg/m3 in January 2015
and 7.92μg/m3and the average concentrations of NOX were 2.94μg/m3 in November 2014, 3.13μg/m3 in December 2014, 2.81μg/m3 in January 2015 and 3.42μg/m3 in February 2015. Due to the exposure of SO2 and NOX in this area the DALYs for chronic respiratory disease obtained 0.15 and for cardiovascular disease it was obtained 0.35 per 10 Lac which indicates that 10 Lac inhabitants surrounding the KPCL area will lose their life expectancy by 128 days due to cardiovascular disease and 55 days due to chronic respiratory disease.Salma AlamMaster of Science in Civil Engineerin
Volumetric and Viscometric Study of N-acetylcysteine in binary and ternary system
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, July 2016.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 76-80)Volumetric and viscometric studies of binary mixtures of ethanol-NAC (N-Acetylcysteine), water-NAC and ternary mixtures of ethanol-water-NAC were done. NAC have been investigated in binary and ternary systems over a concentration range of (1-18) % (w/v) at 298.15 to 323.15 K at 5 K intervals.
Densities of the binary systems, water-NAC and ethanol-NAC have been found to be increased with increasing concentration of NAC and decreased with increasing temperature. Densities of water-NAC have been found higher than that of ethanol-NAC system. On the other hand, in ternary system densities increased with the increasing ratio of water in ethanol-water mixtures. The densities of ternary system are higher than binary system.
The apparent molar volumes, of both binary and ternary mixtures were determined from the densities of the mixtures. The values have been found to be positive throughout the whole concentration range for NAC in ethanol, water and aqueous ethanol systems. The apparent molar volumes, of NAC in ethanol, water and aqueous ethanol were found to be increased with concentration at all temperatures. These results may be due to the solute-solvent, and solute-solute interaction through H-bond, dipole-dipole and S˖˖˖S linkage in the solutions. values were found to be increased with increasing temperature at any concentration of the solution may be due to increased thermal agitation at higher temperatures. It may also be assumed as the concentration increases because solute-solute interactions by S˖˖˖S linkage start to gain importance in addition to solute-solvent interactions. This shows that values are dependent upon concentration as well as the temperature.
The apparent molar volumes at infinite dilution ( ) were computed by extrapolating values to zero concentration. The values provide information on solute-solvent interactions, as solute-solute interactions can be assumed to be eliminated at infinite dilution. The variations of both values with temperature were examined. Values were found to be increased with increasing temperature for all systems. Investigated systems showed small positive values for Sv which indicate that the solvation process involve strong interaction but not pure ionic. The apparent molar expansivities at vii infinite dilution ( 0 ) were found to be positive. Positive values indicate that, on heating some NAC molecules may be released from the solvation layer of ion.
Viscosity values, η of NAC in ethanol, water and aqueous ethanol were found to be increased with concentration at all five temperatures but decreased with the increase of temperature. The increase of η values of NAC with concentration can be attributed to the increase in both solute-solvent and solute-solute interactions with concentration as mentioned. At the same time, at a constant temperature and concentration, values of η are found to be increased with the ratio of the water in ethanol-water of ternary system but in binary system ethanol-NAC is higher than water-NAC viscosity because of larger molecule of ethanol.
The change of free energy values for viscous flow, ∆G* were found to be positive indicate that work has to be done to overcome the energy barrier for the flow process. The positive ΔH values indicate that work has to be done for all the investigated systems. That is, the viscous flow is not thermodynamically favored for the systems studied. The ∆S* values are positive for all the systems studied except ethanol–NAC system. This means that except ethanol–NAC system other binary and ternary systems are random that those of the pure one.Utpal Kumar GoshMaster of Science in Chemistr