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The cleaning of particles from smooth and rough paper surfaces using a high-speed CO2 snow jet was investigated. The measurements included characterization of the jet properties, determination of the cleaning efficiency, and evaluation of any possible adverse effects. The method was compared with nitrogen jet cleaning and dry cleaning by commercial materials. The results showed that the CO2 snow jet is able to effectively remove particles from the paper surface and did not cause any observable degradation. The CO2 snow jet cleaning compared with the mechanical dry cleaning showed similar effectiveness without any adverse effects on the paper surface. It was proved that the CO2 snow technique is a suitable method for cleaning common types of paper materials. [ABSTRACT FROM AUTHOR]

Over the past few decades, detonation nanodiamonds (NDs) have gained increased attention due to their unique physicochemical properties. Various methods for preparation of ND suspensions have been introduced. This paper presents thermally annealed nanodiamonds dispersed via sonication and separated by centrifugation in deionized water and dimethylformamide in five weight concentrations ranging from 0.05 to 1 wt%. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were applied to study the thermal behavior of NDs. Crystallographic properties of air-annealed and dispersed NDs were examined by means of X-ray diffraction (XRD). Nanodiamond dispersions were analyzed by static light scattering (SLS), dynamic light scattering (DLS), ultra-small- and small-angle X-ray scattering (USAXS/SAXS), and high-resolution transmission electron microscopy (HRTEM). SLS and DLS give similar results of ND− aggregates mean size between ~ 61 and 73 nm, regardless of solvent type and nanoparticle concentration. For dispersions with increasing concentrations of NDs, neither increased aggregate size nor different kinetics of separation during sonication and centrifugation were observed. USAXS/SAXS provided the aggregates size (2Rg) in the range from 57 to 65 nm and size of primary particles from 5.4 to 5.8 nm. HRTEM also showed presence of larger aggregates with tens of nanometers in size in both water and DMF dispersions, and size of primary particles ranging from 5.5 to 6 nm in very good agreement with SAXS. [ABSTRACT FROM AUTHOR]

Silica-titania mixed oxides and composites have been broadly examined for their physical and catalytic properties, but titanium monoxide-silicon monoxide counterparts have yet drawn very little attention. Here we report that laser-induced processing of mixed silicon and titanium monoxides results in reactions yielding a nanostructured Ti/Si/O composite absorbing visible light. Changes in the composition of intimately mixed μm-sized particles of silicon monoxide (SiO) and titanium monoxide (TiO) induced by scanning of a cw CO laser beam along the TiO-SiO pellet surface were examined by FTIR and Raman spectroscopy, X-ray diffraction and electron microscopy. They are shown to consist in the evolution of TiO (rutile and anatase), titanium suboxides (TiO, TiO), silica and amorphous binary SiO, TiO and ternary SiTiO nano-phases which contain less or more O than SiO and TiO monoxides. These products are ascribed to concurrent silicothermal reduction of TiO and O-transfer between SiO and TiO due to interdiffusion of Si- and Ti-based species. These reactions taking place under transient localized heating are not inhibited by passivation shells around SiO and TiO particles. The laser-produced Ti/Si/O composite shows absorption band at 425 nm tailing up to 1100 nm. Its solar-light photocatalytic activity in decolorization of Methylene Blue is compared to that of the unheated SiO and TiO powders absorbing only in UV region. [ABSTRACT FROM AUTHOR]