in spite of the fact that cementitious and concrete materials are mainly used on a large scale and inhuge quantities for roads, dams, bridges and building constructions, the mechanical behavior of thesematerials depends to a great extend on structural elements and phenomena which are effective on amicro and nanoscale. although this is well known by researchers, material producers and engineersf...

in the present work, highly efficient oxidation of sulfides catalyzed by moo2(acac)2 supported on multi-wall carbon nanotubes, mwcnts, modified with 1,2-diaminobenzene (dab) and 2-aminophenol (ap), at room temperature are reported. the effects of various parameters such as reaction time, solvent, catalyst amount, oxidant, etc, were studied. these heterogenized catalysts showed high activity in ...

a new hydroxylamine sensor has been fabricated by immobilizing oxadiazol denvative at the surface ol aglassy carbon electrode (gce) modified by multi-wall carbon nanotube (mivcnt). the adsorbed thin illms oroxadiazol derivative on the mwcnt modified gce show a pair of peaks with surface confined characierisnus.the oxadiazol derivative mwcni (omwcnt) modified gce shows highly catalytic activity ...

in the present work, highly efficient oxidation of sulfides catalyzed by moo2(acac)2 supported on multi-wall carbon nanotubes, mwcnts, modified with 1,2-diaminobenzene (dab) and 2-aminophenol (ap), at room temperature are reported. the effects of various parameters such as reaction time, solvent, catalyst amount, oxidant, etc, were studied. these heterogenized catalysts showed high activity in ...

We demonstrate a simplified synthesis technique for double-wall carbon nanotubes that is an adaptation of chemical vapor deposition (CVD) techniques used previously for the production of single-wall nanotubes. Double-wall nanotubes (DWNTs) provide ideal geometries for numerous fundamental structural, electronic, thermal and vibrational studies, as well as providing a unique new platform for pra...

The fundamental relations governing the geometry of carbon nanotubes are reviewed, and explicit examples are presented. A framework is given for the symmetry properties of carbon nanotubes for both symmorphic and non-symmorphic tubules which have screw-axis symmetry. The implications of symmetry on the vibrational and electronic structure of ID carbon nanotube systems are considered. The corres...

The mechanical compressive properties of individual thin-wall and thick-wall TiO(2) nanotubes were directly measured for the first time. Nanotubes with outside diameters of 75 and 110 nm and wall thicknesses of 5 and 15 nm, respectively, were axially compressed inside a 400 keV high-resolution transmission electron microscope (TEM) using a new fully integrated TEM-atomic force microscope (AFM) ...

The iodide (I!)-triiodide (I3 ) redox pair was used as a model system to evaluate the potential catalytic activity of various carbon nanotubes. Aqueous solutions of hydroiodic acid were irradiated with ultraviolet light in the presence of single wall, multi-wall, boron-doped and nitrogen-doped multi-wall carbon nanotubes. The nitrogen-doped multi-wall carbon nanotubes showed significant catalyt...

Uniform dispersion of pre-synthesized nanotubes in metal matrices is difficult to achieve, and there is substantial damage to the nanotubes during subsequent composite fabrication. The demonstration of an in-situ process involving chemical vapor deposition of single-wall and multi-wall carbon nanotubes into iron matrices without the concomitant formation of iron carbides is reported here. It wa...