Filter Medias from Granulated Foam-glass, Properties Investigated for Water Treatment Possibilities

Inorganic material – granulated foam-glass produced from glass breakage in small porous granule shape. Foam-glass is gotten by connecting thoroughly grounded glass with foamers, later this composition is heated in the furnace in especially high temperature and is turned into various diameter greyish granules. Granulated foam-glass is a unique ecological material of which inner structure pores are arranged in such a way that air is trapped inside. Foam-glass production technology is one of the most advanced since the product is made from secondary raw materials, not leaving any third row waste. From granule surface images it can be seen that granule surface has pores and voids, some of these pores are closed, others are connected with granule’s inner pores, all pore walls are smooth, and the wall material is vitrified. Pores and voids are arranged chaotically in smaller granules, bigger granules inner space structure is tidy, bigger part is occupied by correctly arranged bigger pores and space between them is filled with smaller pores. Granules are composed of amorphous phase, in mineralogical composition can emit one material cristobalite. In the work were researched two fraction granules: 0/2 and 2/4 as well as determined 0/4 fraction granular-metric composition. Researched and determined main physical granule properties and properties related to water effect to the material, shown in micro-structural granule surface and inner structure images. According to explored properties it can be noted that granules can be adapted in water cleaning technologies.

Effect of RF Power on the Chemical Bonding and Humidity Sensing Properties of a-CNx Thin Films

Amorphous carbon nitride (a-CNx) thin films were deposited using radio frequency plasma enhanced chemical vapor deposition (rf-PECVD) technique. A set of a-CNxthin films were prepared using pure methane (CH4) gas diluted with nitrogen (N2) gas. The rf power was varied at 50, 60, 70, 80, 90 and 100 W. The characterization techniques used were Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscope (FESEM). Humidity sensing properties of the a-CNxthin films were investigated by recording their electrical response to relative humidity (RH) at room temperature. Chemical bonding analysis clearly showed the presence of nitrile bands in the deposited films. The FESEM images of the films show a porous, granule-like and dendritic morphology. The average resistance of the a-CNxthin film is changed from 23.7 kΩ to 5.8 kΩ in the range of 5 to 95%RH. The films show a good response and repeatability as a humidity sensing materials. This work showed that rf power has a significant effects on the chemical bonding, morphology and electrical properties of the a-CNxfilms.

Nonlinear Smoluchowski slip velocity and micro-vortex generation

When an electric field is applied across a conducting and ion-selective porous granule in an electrolyte solution, a polarized surface layer with excess counter-ions is created. The depth of this layer and the overpotential V across this layer are functions of the normal electric field j on the granule surface. By transforming the ionic flux equations and the Poisson equation into the Painlevé equation of the second type and by analysing the latter's asymptotic solutions, we derive a linear universal j–V correlation at large flux with an electrokinetic slip length β. The flux-induced surface polarization produces a nonlinear Smoluchowski slip velocity that can couple with the granule curvature to produce micro-vortices in micro-devices. Such vortices are impossible in irrotational electrokinetic flow with a constant zeta-potential and a linear slip velocity.