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

Commercial production of nanoparticles (NP) has created a need for research to support regulation of nanotechnology. In the current study, microbial biofilm communities were developed in rotating annular reactors during continuous exposure to 500 μg L(-1) of each nanomaterial and subjected to multimetric analyses. Scanning transmission X-ray spectromicroscopy (STXM) was used to detect and estim...

The synthesis of inorganic nanotubes (INT) from layered compounds of a small size (<10 nm in diameter) and number of layers (<4) is not a trivial task. Calculations based on density functional tight-binding theory (DFTB) predict that under highly exergonic conditions, the reaction could be driven into a “window” of (meta-) stability, where 1–3-layer nanotubes will be formed. Indeed, in this stu...

We report the atomic-scale imaging with concurrent transport measurements of the breakdown of individual multiwall carbon nanotubes inside a transmission electron microscope equipped with a piezomanipulator. We found unexpectedly three distinct breakdown sequences: namely, from the outermost wall inward, from the innermost wall outward, and alternatively between the innermost and the outmost wa...

We report a theoretical analysis of the phonon thermal conductance, κ(T ), for single wall carbon nanotubes (SWCN). In a range of low temperatues up to 100K, κ(T ) of perfect SWCN is found to increase with temperature, approximately, in a parabolic fashion. This is qualitatively consistent with recent experimental measurements where the tube-tube interactions are negligibly weak. When the carbo...

Today’s business environment is causing utilities to examine methods to cut costs and to maximize revenues. Development of a comprehensive program for marketing and utilization* of coal combustion by-products (CCBPs) by a utility can generate additional revenue streams; reduce operating costs at plants; and defer capital costs of developing new waste disposal capacity. These factors can be opti...

We describe spectroscopy measurements of double wall carbon nanotubes using a displacement photocurrent technique. Peaks in the photocurrent are observed at excitation energies corresponding to the spacing of van Hove singularities for both the inner and outer shells of the nanotube. The shell assignment for the peaks can be made by comparing the spectra before and after the formation of the in...