The unsteady mixed convection boundary layer flow near the stagnation point on a heated
vertical plate embedded in a fluid saturated porous medium is studied. It is assumed that
the unsteadiness is caused by the impulsive motion of the free stream velocity and by sudden
increase in the surface temperature. Both the buoyancy assisting and the buoyancy
opposing flow situations are considered with combined effects of the first and second order
resistance of solid matrix of non-Darcy porous medium, variable viscosity and radiation.
The problem is reduced to a system of non-dimensional partial differential equations,
which is solved numerically using the Keller-box method. The features of the flow and
the heat transfer characteristics for different values of the governing parameters are analyzed
and discussed. The surface shear stress and the heat transfer of the present study
are compared with the available results and a good agreement is found.

Analytical descriptions of the geometric phases (GPs) for the total
system and subsystems are studied for a current biased Josephson
phase qubit strongly coupled to a lossy LC circuit in the dispersive
limit. It is found that, the GP and purity depend on the damping
parameter which leads to the phenomenon of GP death. Coherence
parameter delays the phenomenon of a regular sequence of deaths
and births of the GP. The asymptotic behavior of the GP and the
purity for the qubit-LC resonator state closely follow that for the
qubit state, but however, for the LC circuit these asymptotic values
are equal to zero.

In this study, Nostoc commune (cyanobacterium) was used as an inexpensive and efficient biosorbent for Cd(II) and Zn(II) removal from aqueous solutions. The effect of various physicochemical factors on Cd(II) and Zn(II) biosorption such as pH 2.0–7.0, initial metal concentration 0.0–300 mg/L and contact time 0–120 min were studied. Optimum pH for removal of Cd(II) and Zn(II) was 6.0, while the contact time was 30 min at room temperature. The nature of biosorbent and metal ion interaction was evaluated by infrared (IR) technique. IR analysis of bacterial biomass revealed the presence of amino, carboxyl, hydroxyl, and carbonyl groups, which are responsible for biosorption of Cd(II) and Zn (II). The maximum biosorption capacities for Cd(II) and Zn(II) biosorption by N. commune calculated from Langmuir biosorption isotherm were 126.32 and 115.41 mg/g, respectively. The biosorption isotherm for two biosorbents fitted well with Freundlich isotherm than Langmuir model with correlation coefficient (r2 < 0.99). The biosorption kinetic data were fitted well with the pseudo-second-order kinetic model. Thus, this study indicated that the N. commune is an efficient biosorbent for the removal of Cd(II) and Zn(II) from aqueous solutions.

In this study, Nostoc commune (cyanobacterium) was used as an inexpensive and efficient biosorbent for Cd(II) and Zn(II) removal from aqueous solutions. The effect of various physicochemical factors on Cd(II) and Zn(II) biosorption such as pH 2.0–7.0, initial metal concentration 0.0–300 mg/L and contact time 0–120 min were studied. Optimum pH for removal of Cd(II) and Zn(II) was 6.0, while the contact time was 30 min at room temperature. The nature of biosorbent and metal ion interaction was evaluated by infrared (IR) technique. IR analysis of bacterial biomass revealed the presence of amino, carboxyl, hydroxyl, and carbonyl groups, which are responsible for biosorption of Cd(II) and Zn (II). The maximum biosorption capacities for Cd(II) and Zn(II) biosorption by N. commune calculated from Langmuir biosorption isotherm were 126.32 and 115.41 mg/g, respectively. The biosorption isotherm for two biosorbents fitted well with Freundlich isotherm than Langmuir model with correlation coefficient (r2 < 0.99). The biosorption kinetic data were fitted well with the pseudo-second-order kinetic model. Thus, this study indicated that the N. commune is an efficient biosorbent for the removal of Cd(II) and Zn(II) from aqueous solutions.

Indan-1,3-dione (1) reacted with 3-dicyanomethylidene-2-oxoindolines
(2a-c) in refluxed ethanol to afford 2-amino-3-cyanospiro{5H-indeno[1,2-b]
pyrane-4,3'-(1’-substitutedindoline)}-2’,5-diones (3a-c) which underwent
different reactions to afford new spiro{indeno[2',1':5,6] pyrano[2,3-d]pyrimidine-
5,3'-(1’-substitutedindoline)} (4a,b)-(12a,b) which are analogues of some
reported biologically active spiropolycyclic compounds.

Indan-1,3-dione (1) reacted with 3-dicyanomethylidene-2-oxoindolines
(2a-c) in refluxed ethanol to afford 2-amino-3-cyanospiro{5H-indeno[1,2-b]
pyrane-4,3'-(1’-substitutedindoline)}-2’,5-diones (3a-c) which underwent
different reactions to afford new spiro{indeno[2',1':5,6] pyrano[2,3-d]pyrimidine-
5,3'-(1’-substitutedindoline)} (4a,b)-(12a,b) which are analogues of some
reported biologically active spiropolycyclic compounds.

Indan-1,3-dione (1) reacted with 3-dicyanomethylidene-2-oxoindolines
(2a-c) in refluxed ethanol to afford 2-amino-3-cyanospiro{5H-indeno[1,2-b]
pyrane-4,3'-(1’-substitutedindoline)}-2’,5-diones (3a-c) which underwent
different reactions to afford new spiro{indeno[2',1':5,6] pyrano[2,3-d]pyrimidine-
5,3'-(1’-substitutedindoline)} (4a,b)-(12a,b) which are analogues of some
reported biologically active spiropolycyclic compounds.

Indan-1,3-dione (1) reacted with 3-dicyanomethylidene-2-oxoindolines
(2a-c) in refluxed ethanol to afford 2-amino-3-cyanospiro{5H-indeno[1,2-b]
pyrane-4,3'-(1’-substitutedindoline)}-2’,5-diones (3a-c) which underwent
different reactions to afford new spiro{indeno[2',1':5,6] pyrano[2,3-d]pyrimidine-
5,3'-(1’-substitutedindoline)} (4a,b)-(12a,b) which are analogues of some
reported biologically active spiropolycyclic compounds.