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Study of Rainfall & Temperature Trend in Bangladesh
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, August 2017.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 91-96)Climatic data collected from Bangladesh Meteorological Department was used for the study. The
regression equation, the coefficient of determination, standard deviation and coefficient of
variation were calculated for the analysis. Mann-Kendall test for trend and Sen’s slope estimates
were also calculated. Annual average temperature (Tavg) in all division is increasing. The Tavg
in Khulna is increasing by 0.007ºC/year, in Dhaka it is increasing by 0.021ºC/year. The average
temperature has also an increasing trend in other divisionsand the rates are 0.0110C/year in
Rajshahi, 0.019ºC/year in Sylhet, 0.0001ºC/year in Rangpur, 0.013ºC/year in Chittagong,
0.012ºC/year in Barisal and 0.003ºC/year in Mymensingh.Annual maximum temperature
(Tmax)has an increasing trend in Khulna, Dhaka, Rajshahi, Sylhet, Barisal and Chittagong
divisions while it has decreasing trend in Rangpur and Mymensingh divisions. The Tmax in
Khulna is increasing by 0.01 ºC/year, in Dhaka it is increasing by 0.0179 ºC/year. And the
maximum temperaturehas also an increasing trend in Rajshahi, Sylhet, Chittagong and Barisal
divisions.The rates of increase are 0.006 ºC/year in Rajshahi, 0.018 ºC/year in Sylhet, 0.020
ºC/year in Chittagong and 0.0178 ºC /year in Barisal divisions. Whereas the maximum
temperature has a decreasing trendat -0.014 ºC/year and -0.004 ºC/year in Rangpur and
Mymensingh divisions respectively. Annual minimum temperatures (Tmin) in all divisions
areincreasing.The Tmin in Khulna is increasing by 0.0058 ºC/year, in Dhaka it is increasing by
0.024 ºC/year. The minimum temperature has also an increasing trend in other divisions and the
rates are 0.016 ºC/year in Rajshahi, 0.021ºC/year in Sylhet, 0.015 ºC/year in Rangpur, 0.007
ºC/year in Chittagong, 0.006 ºC/year in Barisal and 0.010 ºC/year in Mymensingh. The Mann-
Kendall test indicates that in Khulna division Tavg has an increasing trend in monsoon and post
monsoon seasons with value of Z 6.31and 2.52 which are statistically significant. This test also
indicates that in Dhaka division,it has an increasing trend in pre-monsoon, monsoon, post
monsoonand winter seasons with value of Z 2.75, 6.23, 5.60 and4.62 respectively which are
statistically significant. In Rajshahi division, it has an increasing trend in monsoon season with
value of Z 6.25which is statistically significant.In Sylhet division, it has an increasing trend
inpre-monsoon, monsoon, post monsoonand winter seasons with Z values of 2.24,6.10, 5.24
and4.60 respectively which are statistically significant.In Rangpur division, it has an increasing
trend in monsoon while decreasing trend in winterseasons with valuesZ of 3.85 and -1.86 which
are statistically significant. In Barisal division,it has an increasing trend in Monsoon and Postmonsoon
seasons with Z values of are 4.77 and 3.48 which is statistically significant. In
Chittagong division, it has an increasing trend in pre-monsoon, monsoon, post-monsoonand
winter seasons with Z values of 2.25,6.44,3.94and 1.79respectively which are statistically
significant.In Mymensingh division,it has an increasing trend inmonsoon season with Z value of
5.11 which is statistically significant. Annual total rainfall has an increasing trend in Khulna,
Rajshahi, Sylhet, Chittagong, Rangpur and Mymensingh divisionswhile decreasing trend in
Dhaka and Barisaldivisions. The total rainfall has an increasing trend in Khulna by 3.392
mm/year, in Rajshahi it is increasing by 2.3279 mm/year. The total rainfall has also an increasing trend in Sylhet, Rangpur, Chittagong and Mymensingh divisions. The rates are 2.6605 mm/year
in Sylhet, 5.5885 mm/year in Rangpur, 1.889 mm/year in Chittagong and 2.283 mm/year in
Mymensingh division. Whereas the total rainfall has a decreasing trends (-2.0292 mm/year) in
Dhaka and (-1.985 mm/year) in Barisal division. The results suggest that temperature and rainfall
are increasing in most of the stations and divisions.Karno Kumar MondalMaster of Science in Physic
Studies on Volumetric and Viscometric Properties on N-Acetylcysteine in Dimethylsulfoxide-Water Mixture
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 2017.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 97-104).The density and viscosity of NAC (~0.10 to ~1.00) mol.L to-1 in H20, DMSO and
DMSO-H20 mixed solutions were measured and studied over the entire molarity range
at (298.15, 303.15, 308.15, 313.15 and 318.15) K temperatures with a view to
determining the molecular interactions among NAC, H20 and DMSO. NAC is a
suithydryl substance widely used as medicine known as best free radical and heavy metal
scavenger in human body. DMSO is a colorless organic polar solvent has led to its largescale
production in recent years with negligible toxicity. DMSO is completely miscible
with universal solvent water. So DMSO-H20 mixture can be a vital binary solution in
investigating NAC; were taken as topic of research in this study. The apparent molar
volumes were obtained from the experimental density data. In the NAC—H20 system the
apparent molar volume of NAC increases, whereas in the NAC—DMSO system it
decreases smoothly. In addition, apparent molar volume at infinite dilution, apparent
molar expansivity, transfer apparent molar volume and S values were also calculated
according to the experimental density data. The apparent molar volume at infinite
dilution gives an idea about the presence of solute—solvent interactions whereas Sv is the
experimental slopes which give an idea about the prevailing solute—solute interactions in
the mixtures. The calculated data indicate that there may be solute-solute and solutesolvent
interactions present in the binary and ternary solutions. Hepler constant which is
used to determine the capacity of solute as a structure maker or structure breaker in
mixed solvent system has also determined. It is seen that NAC has good structure
making property in ternary solutions than the binary systems. Both binary and ternary
systems showed rapid increase of viscosity values with the increased NAC concentration
but the values of viscosity decreased with the increase of temperature. The viscosity data
were employed to determine the viscosity (A, B) coefficients, change of free energy,
AG*, change of enthalpy, H* and change of entropy, S*. From these thermodynamic
parameters state of the spontaneity of the investigated systems were known. Moreover,
negative A and positive B co-efficients suggesting that weak solute-solute but strong
solute-solvent interaction present in the binary and ternary solution. On the basis of this
data, the predominant molecular interactions occurring between NAC—H20, NAC—
DMSO and NAC—DMSO—H2O were found to be solute-solvent interaction. The results
suggest that there is a significant effect of NAC on water and DMSO.Md. Mehidi Hassan KhanMaster of Science in Chemistr
