Biomedical subjects

B. D. Kulkarni

Publications and source records attributed to B. D. Kulkarni.

4 recordsLinked to original sources

PubMed2001

Synthesis and Characterization of Ferrierite-Type Zeolite in the Presence of Nonionic Surfactants.

Pure-phase ferrierite (FER) zeolite has been synthesized in the presence of small amounts of nonionic surfactants, Tween 20 and Tween 80. The input SiO(2)/Al(2)O(3) molar ratio has been varied over a range of 25 to 150. The results confirm that a small amount of pyrrolidine acts as a template and is necessary. The effects of varying concentration of surfactant on ferrierite crystallization and output SiO(2)/Al(2)O(3) molar ratio are reported. The results also show that in the absence of pyrrolidine, ZSM-5 cocrystallized with FER, whereas in the absence of a nonionic surfactant the yield and crystallization of FER are very poor. The XRF analysis shows the changes in SiO(2)/Al(2)O(3) output molar ratios as the surfactant concentration changes. The XRD data show that the samples are fully crystalline and pure. The TG/DTA of the sample shows its structural stability. The scanning electron microscopy results show changes in particle size with varying concentration of nonionic surfactant. Copyright 2001 Academic Press.

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PubMed2001

Synthesis of Ferrierite-Type Zeolite in the Presence of a Catalytic Amount of Pyrrolidine and Sodium Bis(2-ethyhlhexyl) Sulfosuccinate.

Synthesis of ferrierite (FER) type zeolite with varying Si to Al ratios in the presence of a catalytic amount of pyrrolidine and sodium bis(2-ethylhexyl) sulfosuccinate (AOT) in aqueous media is reported. The surfactant moieties direct pyrrolidine molecules in a particular fashion, resulting in a sixfold decrease in the required amount of template as compared to conventional procedure, for FER crystallization. The product obtained was highly crystalline and pure. In the presence of AOT alone, ferrierite co-crystallized with the ZSM-5 phase, indicating AOT is not acting as a structure-directing agent and a small concentration of pyrrolidine ( approximately 2 wt%) template is essential for the ferrierite crystallization. A scanning electron micrograph showed uniformity in crystals (average 2-3 µm) consisting of broad plate type morphology. The crystal structure of FER (AOT/Py) maintains structural integrity until about 1000 degrees C. FER (AOT/Py) has been further characterized by employing XRD, XRF, IR, and TG/DTA techniques. Copyright 2001 Academic Press.

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PubMed1999

Obtaining functional form for chaotic time series evolution using genetic algorithm.

A genetic algorithm (GA) based strategy is presented for deducing an exact or near-exact functional form from a time series. The GA formalism proposed here utilizes (i) the "postfix" representation with a view to reduce the procedural complexities and (ii) the "elitist mating" scheme to produce fitter offspring strings. The GA procedure is exemplified by considering chaotic time series of the well-known logistic, Henon and universal maps. The GA correctly recovers the underlying functional forms for the respective time series. Measurements from a number of finite-dimensional physical, biological, and other systems often give rise to complex time series and the presented methodology should prove useful in obtaining functional forms describing accurately the evolution of the time series. (c) 1999 American Institute of Physics.

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PubMed1998

Synchronization and control of spatiotemporal chaos using time-series data from local regions.

In this paper we show that the analysis of the dynamics in localized regions, i.e., sub-systems can be used to characterize the chaotic dynamics and the synchronization ability of the spatiotemporal systems. Using noisy scalar time-series data for driving along with simultaneous self-adaptation of the control parameter representative control goals like suppressing spatiotemporal chaos and synchronization of spatiotemporally chaotic dynamics have been discussed. (c) 1998 American Institute of Physics.

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