Md Mehdi Hasan - Academia.edu (original) (raw)

Papers by Md Mehdi Hasan

Water research, Nov 29, 2018

A fairly clean ice cover can form over a contaminated water pond when the air-cooled surface of w... more A fairly clean ice cover can form over a contaminated water pond when the air-cooled surface of water freezes and impurities are efficiently expelled to the remaining water underneath. Natural freeze crystallization has recently been studied as a potential wastewater purification method with aqueous solutions on a laboratory scale. The effect of impurity inclusions on ice strength has been researched in model ice basins over the past few decades. It is of interest to discover how efficiently natural freeze separation works under real weather conditions before freezing can be utilized for wastewater treatment application. Herein, understanding the mechanical strength properties of naturally frozen wastewater (ice) is important when planning ice breaking and harvesting devices. This research implemented in-situ measurements of the flexural and compressive strength of ice in natural ice-covered environments of a freshwater lake, two peatlands and three mining site basins, and compares ...

Chemical Engineering & Technology, 2014

Freezing point depression (FDP) modeling was performed for selected aqueous nitrate and sulfate s... more Freezing point depression (FDP) modeling was performed for selected aqueous nitrate and sulfate salt solutions to evaluate Pitzer ion interaction parameter values at 273.15 K. 1‐1 and 1‐2 electrolyte solutions of NaNO3, KNO3, NH4NO3, Na2SO4, K2SO4, and (NH4)2SO4 were studied. New Pitzer parameter values of β0, β1, and Cϕ were obtained for the studied electrolyte solutions. FDP modeling was also used to determine temperature derivatives of interaction parameters for the Pitzer model for selected salt solutions. Osmotic and activity coefficients using the new parameter values are also presented.

Industrial & Engineering Chemistry Research, 2014

A novel calculation method (see the article in Ind. Eng. Chem. Res. 2014, 53, 5608−5616) was appl... more A novel calculation method (see the article in Ind. Eng. Chem. Res. 2014, 53, 5608−5616) was applied in this work to evaluate the ion interaction parameters for the Pitzer model from freezing points of aqueous solutions of pure electrolytes. The freezing-point depression data from aqueous solutions of salts consisting of chloride, bromide, nitrate, chlorate, perchlorate, formate, and acetate ions as anions and lithium, sodium, and potassium ions as cations were used in the present study. The literature data from the research group of Scatchard (

P.G. Department of Physical Chemistry, M.S.G. College, Malegaon Camp-423 105, Dist. Nashik,<br... more P.G. Department of Physical Chemistry, M.S.G. College, Malegaon Camp-423 105, Dist. Nashik, Maharashtra, India E-mail : mihasan@rediffmail.com L. V. H. College, Nashik, Maharashtra, India Manuscript received 11 October 2007, revised 5 August 2008, accepted 7 August 2008 The densities and viscosities of glucose solutions in water and in 0.05, 0.1, 0.5, 1.00 M NaCI, NaBr, KCI and KBr have been measured at 298.15, 303.15, 308.15 and 313.15 K. From densities (ρ), the limiting partial molar volumes (φ0v) have been evaluated. The viscosity data have been analyzed with the help of the modified Jones-Dole equation and the corresponding viscosity B-coefficients have been calculated.

Zenodo (CERN European Organization for Nuclear Research), 2005

The viscosities of cesium halides (CI-, Brand 1-), (C~H 9) 4 NHr, NaBr and NaBPh 4 have been meas... more The viscosities of cesium halides (CI-, Brand 1-), (C~H 9) 4 NHr, NaBr and NaBPh 4 have been measured in (0, 20, 40, 80) mass% aqueous acetone at 298.15 K. The viscosity B-coefficicnts have been calculated by using the Jones-Dole equation. The ionic B-coefficicnts have been determined using the reference electrolytes NaBPh 4 , NaBr and (C 4 H 9) 4 NBr.

Russian Journal of Physical Chemistry A, 2010

The densities and viscosities of tetra n alkylammonium bromides, R 4 NBr (R = CH 3 to C 4 H 9), N... more The densities and viscosities of tetra n alkylammonium bromides, R 4 NBr (R = CH 3 to C 4 H 9), NaBPh 4 and NaBr have been measured in 0, 10, 30, 50, 70, 90, and 100 wt % ethanol + water at 303.15 K. From the densities, apparent and limiting partial molar volumes of the electrolytes and ions in these mixture have been evaluated. The viscosity data have been analyzed with the help of Jones-Dole equation and the viscosity B coefficients have been determined. The viscosity B coefficients are further split up in to their ionic contributions.

Journal of Solution Chemistry, 2011

Densities, viscosities and speeds of sound of binary mixtures of ethanol, propan-1-ol, butan-1-ol... more Densities, viscosities and speeds of sound of binary mixtures of ethanol, propan-1-ol, butan-1-ol and pentane-1-ol with n-butyl acetate have been measured over the entire range of composition at temperatures of 298.15, 303.15, 308.15 and 313.15 K and atmospheric pressure. From the experimental densities, viscosities and speeds of sound, the excess molar volumes V E , deviations in viscosity η, and deviations in isentropic compressibility κ S have been calculated. The excess molar volumes and deviations in isentropic compressibility are positive for all the binary systems studied over the whole composition, while deviations in viscosities are negative for all of the binary mixtures. The excess molar volumes, deviations in viscosity, and deviations in isentropic compressibility have been fitted to a Redlich-Kister type polynomial equation. FTIR and 1 H-NMR studies of these mixtures are also reported. Keywords Density • Viscosity • Speed of sound • IR • 1 H-NMR • n-Butyl acetate • Alkanols

Journal of Chemical & Engineering Data, 1997

ABSTRACT The densities of tetraalkyl ammonium bromide, R4NBr (R=CH3 through n-C4H9), NaBPh4 and N... more ABSTRACT The densities of tetraalkyl ammonium bromide, R4NBr (R=CH3 through n-C4H9), NaBPh4 and NaBr solutions in (0, 10, 30, 50, 70, 90, and 100) mass% ethanol+water have been measured over the whole composition range at 298.15 K. From the densities, apparent and limiting partial molar volumes of the electrolytes and ions in these mixtures have been evaluated.

Fluid Phase Equilibria, 2007

Densities, viscosities, and ultrasonic velocities of binary mixtures of chloroform with propan-1-... more Densities, viscosities, and ultrasonic velocities of binary mixtures of chloroform with propan-1-ol and butan-1-ol have been measured over the entire range of composition, at (303.15 and 313.15) K and at atmospheric pressure. From the experimental data, excess molar volumes (V E), deviations in viscosity (∆η), and excess isentropic compressibility (κ s E) have been calculated. The excess molar volumes and isentropic compressibility for propan-1-ol and butan-1-ol are positive while deviations in viscosity are negative. The results have been interpreted in terms of intermolecular interactions. These are further fitted to the Redlich-Kister polynomial equation.

Work Function Tuning in Sub-20nm TiN Metal GateMechanism and Engineering Md. Mehedi Hasan Scaling... more Work Function Tuning in Sub-20nm TiN Metal GateMechanism and Engineering Md. Mehedi Hasan Scaling of transistors (the building blocks of modern information age) provides faster computation at the expense of excessive power dissipation. Thus to address these challenges, high-k/metal gate stack has been introduced in commercially available microprocessors from 2007. Since then titanium nitride (TiN) metal gate’s work function (Wf) tunability with its thickness (thickness increases, work function increases) is a well known phenomenon. Many hypotheses have been made over the years which include but not limited to: trap charge and metal gate nucleation, nitrogen concentration, microstructure agglomeration and global stress, metal oxide formation, and interfacial oxide thickness. However, clear contradictions exist in these assumptions. Also, nearly all these reports skipped a comprehensive approach to explain this complex paradigm. Therefore, in this work we first show a comprehensive ph...