Joydeep Dutta - Academia.edu (original) (raw)

Papers by Joydeep Dutta

TOPICAL REVIEW: Hydrothermal growth of ZnO nanostructures

Science and Technology of Advanced Materials, 2009

One-dimensional nanostructures exhibit interesting electronic and optical properties due to their... more One-dimensional nanostructures exhibit interesting electronic and optical properties due to their low dimensionality leading to quantum confinement effects. ZnO has received lot of attention as a nanostructured material because of unique properties rendering it suitable for various applications. Amongst the different methods of synthesis of ZnO nanostructures, the hydrothermal method is attractive for its simplicity and environment friendly conditions. This review summarizes the conditions leading to the growth of different ZnO nanostructures using hydrothermal technique. Doping of ZnO nanostructures through hydrothermal method are also highlighted.

Bilevel programming with convex lower level problems

In this article we develop certain necessary optimality condition for bilevel programming problem... more In this article we develop certain necessary optimality condition for bilevel programming problems with convex lower-level problem. The results are abstract in nature and depend on an important construction in nonsmooth analysis called the coderivative of a set-valued map.

Mathematical Methods of Operations Research, 2006

We consider vector optimization problems on Banach spaces without convexity assumptions. Under th... more We consider vector optimization problems on Banach spaces without convexity assumptions. Under the assumption that the objective function is locally Lipschitz we derive Lagrangian necessary conditions on the basis of Mordukhovich subdifferential and the approximate subdifferential by Ioffe using a non-convex scalarization scheme. Finally, we apply the results for deriving necessary conditions for weakly efficient solutions of nonconvex location problems.

New necessary optimality conditions in optimistic bilevel programming

Optimization, 2007

The article is devoted to the study of the so-called optimistic version of bilevel programming in... more The article is devoted to the study of the so-called optimistic version of bilevel programming in finite-dimensional spaces. Problems of this type are intrinsically nonsmooth (even for smooth initial data) and can be treated by using appropriate tools of modern variational analysis and generalized differentiation. Considering a basic optimistic model in bilevel programming, we reduce it to a one-level framework

Mathematical Programming

Bilevel programming problems are often reformulated using the Karush–Kuhn–Tucker conditions for t... more Bilevel programming problems are often reformulated using the Karush–Kuhn–Tucker conditions for the lower level problem resulting in a mathematical program with complementarity constraints(MPCC). Clearly, both problems are closely related. But the answer to the question posed is “No” even in the case when the lower level programming problem is a parametric convex optimization problem. This is not obvious and concerns local optimal solutions. We show that global optimal solutions of the MPCC correspond to global optimal solutions of the bilevel problem provided the lower-level problem satisfies the Slater’s constraint qualification. We also show by examples that this correspondence can fail if the Slater’s constraint qualification fails to hold at lower-level. When we consider the local solutions, the relationship between the bilevel problem and its corresponding MPCC is more complicated. We also demonstrate the issues relating to a local minimum through examples.

Optimality conditions for bilevel programming problems

Optimization, 2006

... In addition, the choice made by player 1 may affect the set of feasible strategies, S, open t... more ... In addition, the choice made by player 1 may affect the set of feasible strategies, S, open to player 2, implying the ... The impracticality of this implicit approach is obvious. ... both to correct the partial gradient and to estimate function values for F[x,y(x)] along a line search direction. ...

Growth of Zinc Oxide Nanowires and Nanobelts for Gas Sensing Applications

Journal of Metastable and Nanocrystalline Materials, 2005

MK Hossain 1 , SC Ghosh 1 , Y. Boontongkong 2 , ... C. Thanachayanont 2 and J. Dutta 1 ... 1Micro... more MK Hossain 1 , SC Ghosh 1 , Y. Boontongkong 2 , ... C. Thanachayanont 2 and J. Dutta 1 ... 1Microelectronics, School of Advanced Technologies, Asian Institute of Technology PO Box 4, Klong Luang, Pathumthani 12120, Thailand, E-mail: joy@ait.ac.th;

Science and Technology of Advanced Materials, 2005

We report the synthesis of luminescent nanoparticles of manganese doped zinc sulfide (ZnS:Mn 2C )... more We report the synthesis of luminescent nanoparticles of manganese doped zinc sulfide (ZnS:Mn 2C ) with an emission peak at around 590 nm. Nanoparticles of ZnS:Mn 2C are prepared by a co-precipitation reaction from homogenous solutions of zinc and manganese salts. Based on Ostwald ripening and surface passivation, we discuss a mechanism for the formation of ZnS:Mn 2C nanoparticles. The reaction proceeds with the nucleation of ZnS crystals, which are immediately passivated by the anions in the solution. This in turn attracts cations including zinc and manganese which contribute to the growth of the crystal. These nanoparticles are sterically stabilized using polyphosphates of sodium namely sodium tripolyphosphate (STTP) and sodium hexametaphosphate (SHMP). The nanoparticles consist of particles of 60-80 nm in diameter, each containing primary crystallites that was estimated from the X-ray diffraction patterns to be at around 2.2 nm.