UTILIZATION OF TOOLS FOR SUCCESSFUL. TROUBLESHOOTING OF STRUCTURAL PROBLEMS

A structural failure problem was solved using an integrated and iterative program of testing and analysis. The steps taken in solving the problem were: analytical calculations; operational testing; qualifications of analytical results; problem identification; design of corrective action; and confirmatory testing.     

Nanomachines: A Roadmap for Realizing the Vision

Journal of Nanoparticle Research -     

Surface-dependent cytotoxicity on bacteria as a model for environmental stress of halloysite nanotubes

Nanoparticles of CoDy_0.1Fe_1.9O₄ were synthesized by sol–gel auto-combustion method. Four samples were synthesized from precursor solutions having different pH values in the range of 2.5–10. X-ray diffraction patterns were analyzed to determine the crystal phase of CoDy_0.1Fe_1.9O₄ nanoparticles synthesized at different pH. The XRD patterns confirm the formation of cubic spinel structure for CoDy_0.1Fe_1.9O₄ nanoparticles synthesized at different pH values. However the single phase is obtained only at pH 7.5, while γ and α-Fe₂O₃ phases appeared at pH 2.5, 5.0, and 10.0. Transmission electron microscopy shows that the structural morphology of the nanoparticles is highly dependent on the pH concentration. Particle size varies in between 24 and 36 nm with respect to change in pH concentration of the sample. Particle size increases to 36 nm with increase in pH up to 7.5 followed by a decrease in particle size for further increase in pH value. Magnetic properties were explored by vibrating sample magnetometry. The variation in pH during the synthesis process changes the size and structural morphology of the nanoparticles, which ultimately causes the variation in the values of the magnetic parameters such as saturation magnetization and coercivity. Infrared spectroscopy is employed to determine the local symmetry in the crystalline solids and to shed light on the ordering phenomenon under the influence of different pH values.     

Vortex lattice transitions in YNi2B2C

We have performed extensive small-angle neutron scattering (SANS) diffraction studies of the vortex lattice in single crystal YNi₂B₂C for B‖c. High-resolution SANS, combined with a field-oscillation vortex lattice preparation technique, allows us to separate Bragg scattered intensities from two orthogonal domains and accurately determine the unit cell angle, β. The data suggest that upon increasing field there is a finite transition width where both low- and high-field distorted hexagonal vortex lattice phases, mutually rotated by 45°, coexist. The smooth variation of diffracted intensity from each phase through the transition corresponds to a redistribution of populations between the two types of domains.     

Application of biomolecular recognition via magnetic nanoparticle in nanobiotechnology

The marriage of biomolecular recognition and magnetic nanoparticle creates tremendous opportunities in the development of advanced technology both in academic research and in industrial sectors. In this paper, we review current progress on the magnetic nanoparticle-biomolecule hybrid systems, particularly employing the recognition pairs of DNA-DNA, DNA-protein, protein-protein, and protein-inorganics in several nanobiotechnology application areas, including molecular biology, diagnostics, medical treatment, industrial biocatalysts, and environmental separations.     

Flow phenomena in floppy tubes

Collapsible tubes, which occur all over the body, have unique properties from the point of view of both physics and physiology. A brief review is attempted of first the basic observable properties, followed by simple theory to explain the steady-flow aspects and an overview of the somewhat more complex theories for unsteady flow, in particular the flow-induced oscillations. The experimental evidence from laboratory studies is reviewed with particular emphasis on the dynamical system aspects. A final section looks at the current position and prospects.