Two-Dimensional Modeling of the Capillary Plasma With the Kinetic Ablation Model
A steady 2-D magnetohydrodynamic model of a capillary discharge is presented. Special attention is paid to the ablation/deposition process at the capillary wall, and the results show distinct 2-D features.
Ablation study in the capillary discharge of an electrothermal gun
In this paper, we study the ablation phenomena associated with the operation of a capillary discharge for an electrothermal gun. Electrothermal-chemical (ETC) guns are used for enhancement of ignition and combustion of an energetic propellant. One of the major components of the ETC system is a plasma source based on a capillary discharge. In this paper, a model of the capillary discharge is developed. In this model, primary attention is paid to the ablation phenomenon. Different characteristic subregions near the ablated surface, namely, a space-charge sheath, a Knudsen layer, and a hydrodynamic layer, are considered. In this formulation, the ablation rate is determined by the parameters at the edge of the Knudsen layer. The kinetic approach is used to determine the parameters at the interface between the kinetic Knudsen layer and the hydrodynamic layer. Coupling the solution of the nonequilibrium Knudsen layer with the hydrodynamic layer provides a self-consistent solution for the ablation rate. Accordin...
Applications of nanocomposite hydrogels for biomedical engineering and environmental protection
Nanocomposite hydrogels are polymeric networks that possess a unique property of hydration. The presence of alcohols, carboxylic acids and amides as hydrophilic moieties in structure of nanocomposite hydrogels enhances their stiffness and water-absorbing capacity. Addition of cross-linker in the synthesis of hydrogels increases their stability under extreme conditions of temperature, pH and pressure. Natural polymer-based nanocomposite hydrogels are biodegradable, highly hydrophilic and possess good mechanical strength. Gelatin, chitin, cellulose, pectin, carrageenan, starch and alginate are natural polymers commonly used to fabricate nanocomposite hydrogels. Nanocomposite hydrogels have special characteristics such as high swelling rate, selectivity and stimuli-sensitive nature. Here we review nanocomposite hydrogels for environmental protection and biomedical engineering. Applications in biomedical engineering include drug delivery agents, wound dressing, tissue engineering and antibacterials. Applications in environmental protection include ion exchangers, adsorption, photocatalysis and soil conditioning. Many nanocomposite hydrogels show excellent adsorption selectivity for heavy metal ions: Cu2+ up to 30.35 mg/g, Pb2+ up to 35.94 mg/g, and Zn2+ and Fe3+ up to 94.34 mg/g. Xanthan gum-based nanocomposite hydrogel has removed 96% dye from industrial effluent as reported. In addition, most of the nanocomposite hydrogels showed better adsorption capacity for pollutants in the pH range from 5 to 7. The nanocomposite hydrogels could also be regenerated and successfully utilized for several times. Nanocomposite hydrogels are therefore good bio-absorbent materials for environmental detoxification.