KUET Institutional Repository (Khulna University of Engineering & Technology)
Not a member yet
1045 research outputs found
Sort by
Study on Convective and Non-Convective Rain of Different Heavy Rainfall Events in the Premonsoon Season 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 Science in Physics, March, 2018.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 94-100).In the present study the Advanced Research WRF (ARW) v3.8.1 model have been used to
simulate the heavy rainfall events in the southeastern regions of Bangladesh during 4, 6 and 7 May 2013 and southern region during 15-16 May 2013. The initial and boundary conditions
are drawn from the global operational analysis and forecast products of National Center for
Environmental Prediction (NCEP-FNL) available at 1o ×1o resolution. The model was configured in single domain, 6 km horizontal grid spacing with 161×183 grids in the eastwest
and north-south directions and 30 vertical levels. Time step of integration is set to 30 seconds for maintaining computational stability as the model uses third-order Runge-Kutta
time integration scheme. In this research, four different microphysics (MP) schemes i.e., Lin
et al., WSM6, Thompson and WDM6 and four different cumulus parameterization (CP)
schemes i.e., Kain-Fritsch (KF), Tiedtke, Zhang-McFarlane (ZM) and Multi-scale Kain-
Fritsch (MSKF) are used to simulate the heavy rainfall events. In this research convective rain and non-convective rain have been studied to observe the effect of these rainfalls on total rainfall and area average rainfall, relative humidity, vertical velocity, reflectivity and vorticity have been predicted and analyzed. The different verification methods such as threat score (TS), equitable threat score (ETS), bias score (BS) and standard deviation (SD) have been computed for accuracy of forecast. Tiedtke scheme has simulated lower rainfall in combination with all chosen MPs in all Bangladesh and also heavy rainfall area on 4, 6 and 7 May. KF scheme coupling with all MPs have simulated similar average rainfall all over Bangladesh on 4 May and WDM6 coupling with KF, ZM and MSKF schemes have simulated almost similar amount of rain in the heavy rainfall region on 7 May. The model simulated heavy rainfall region is shifted from Khepupara to Mongla on 15 May all MPs and CPs and on 16 May, observed maximum rain at Barisal and Patuakhali matched but higher rain area is found at Khepupara. Simulated convective rain position matched with the observed maximum rain on 15 May but the amount is not significant for all MPs and CPs and on 16 May insufficient Convective Rain have simulated. Maximum amount of rain is found mainly non-convective for all MPs and CPs. On 16 May Lin et al. scheme coupling with all CPs have simulated almost similar results in the heavy rain area and all over Bangladesh all MPs gives higher results. WSM6 and WDM6 schemes coupling with ZM and MSKF schemes gives the better performance on the basis of Threat Score, Equivalent Threat Score and Bias Score on 4, 6 and 7 May 2013 and during 15- 16 May 2013.Md. Adnan FihirMaster of Science in Physic
Fabrication of a pH Sensor Based on Metal Oxide Nanoparticle and Ion Exchanging Surfaces
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, February 2018.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 96-107).The nanostructures of metal oxides are attractive and important for nanosensor research in
the broad range of applications in various fields of biological, environmental and
analytical chemistry. Due to their potential applications and special properties metal
oxides nanoparticle have concerned considerable attention which are strongly related with
their size, structure and morphology. Among the metal oxide, cupric oxide (CuO) is
found to be one of the most popular oxide. Owing to its exceptional electrochemical
activity and the possibility of promoting electron transfer at a low potential, availability,
stability, good morphological and structural control of the synthesized nanostructures,
CuO
is a good candidate for pH sensing application.
In this paper, an electrochemical pH sensor that has been fabricated using copper oxide
modified glassy carbon electrode (CuO/GCE). The difference in peak potential shift while
using CuO/GCE as pH sensor was measured using square wave voltammetry (SWV); and
was found to be linear over the range of pH 3-9, with a sensitivity of
60
mVpl-f'. The
sensor shows a potential drift of 1.97 —3.33 % after three hours of continuous use; and
could retain
95% of its initial sensitivity after 1 week of use. The electrode was found to
respond both in the presence and absence of oxygen, further expanding the potential
applications to include it
into de-oxygenated environments. This prototype has been
tested in real samples and verified by using commercial pH meter. The CuO based sensor
showed good sensitivity and long term stability that may show the way to develop a low
cost solid state pH sensor for a wider range of applications.Sanzida Mohosina TomaMaster of Science in Chemistr
Synthesis and Spectral Characteristics of Substituted 2,6-Dibenzylidene Cyclohexanone
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, May 2018.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 51-58).The design and synthesis of substituted 2,6-Dibenzylidene cyclohexanone based bischalcone
derivatives were studied in this research through one of the most important
Claisen-Schmidt condensation reaction of donor-acceptor conjugated system and their
spectral properties has been studied. A number of substituted 2,6-Dibenzylidene
cyclohexanone was synthesized through the reaction of commercially available para
substituted benzaldehyde and cyclohexanone in presence of basic NaOH, where NaOH acts
as a catalyst. The structures of the synthesized products were characterized by their
physical, chemical and UV, IR & 1H NMR spectra. The compounds were soluble in most
organic solvents. 2,6-Bis-(4-dimethyl-amino benzylidene)-cyclohexanone showed
acidochromic behavior with the change of pH. This compound when interacts with acids
changed the color of compounds due to the presence of chromophore. 2,6-Dibenzylidenecyclohexanone
1 absorbed at 330 nm and 2,6-Bis-(4-dimethylamino-benzylidene)-
cyclohexanone 5 disclosed high absorption at 452 nm. The bathochromic shifts for
compound 5 is due to the presence of electron donating N(CH3)2 substituents and the
hypsochromic shifts for compound 1 is mainly due to the basic chalcone framework where
no substituent is present. Also 2,6-Bis-(4-methoxy-benzylidene)-cyclohexanone 4 showed
absorption at 359 nm (bathochromic shifts, lesser than compound 5) due to the presence of
electron donating MeO substituents. Probably the halogen substituent contributed very
little effect to the absorption and hence 2,6-Bis-(4-chloro-benzylidene)-cyclohexanone 2
exhibited absorption at 333 nm. Further 2,6-Bis-(4-nitro-benzylidene)-cyclohexanone 3
showed absorption at 340 nm.
The solvatochromic behavior study of these compounds revealed that when these
compounds were dissolved in different solvents (Ethanol, Ethyl acetate and
Dichloromethane) formed hydrogen bonds on the basis of the polarity of the solvent and
stabilized the product. EtOH is a polar protic solvent and the polarity of etanol is more than
ethyl acetate and dichloromethane hence in case of compounds 1,4 & 5 exposed greater
max (bathochromic shifts) in EtOH due to the formation of hydrogen bonds. This shifts
turned to hypsochromic from ethyl acetate to DCM as these are aprotic. This could be due
to the decrease in energy of the excited state as a function of increase in solvent polarity,
which is in the order: DCM < Ethyl acetate < EtOH and stabilized the compound.Hasan Md. Ashekul IslamMaster of Science in Chemistr
