Abstract: The combustion of cellulose nitrate (NC) in ballasted mixtures containing an organic binder and nickel hydroxycarbonate (NiOHCO3) or silver carbonate (Ag2CO3) as precursors has been found to produce Ni or Ag nanoparticles. Formation of Ni and Ag nanoparticles in the wave of flameless combustion of NC was monitored by the time-resolved X-Ray diffraction (TRXRD) method. During the formation of the Ag nanoparticles, the diffraction patterns exhibited only signals from decreasing amounts of the precursor and newly simultaneously formed 20-30 nm silver particles. It has been detected that in the systems with NiOHCO3 the formation of the Ni 5-10 nm crystals proceeded via some 2-3 seconds diffraction-silent intermediate state of the whole system.
Abstract: Concealed cistern control panels are the systems allowing the water inside the built-in reservoir to flow into the toilet bowl when it is necessary. In order to provide the water inside the reservoir to flush into the toilet bowl after the toilet is used, it is necessary to apply force on the control panels. Therefore, the panel surface is pressed with fingers. Especially in public places such as shopping malls, schools, hospitals; the sweat, oil and cosmetics passing through the fingers in a very short time leave spots on the panel surfaces. In order to clean the spots, it is needed to use cleaning materials with chemical content. This situation leads extra cost and as well as time consuming process. For this reason antifingerprint coated panels are required. In this study, antifingerprint coating systems were developed and to improve the coating performance such as mechanical and chemical resistance, different polyurethane composition ratios were studied and effectiveness of the coating systems were investigated by using characterization methods (SEM, EDX, FTIR).
Abstract: Calcium hydroxyapatite (Ca10(PO4)6(OH)2, CHAp), tricalcium phosphate (Ca3(PO4)2, TCP) and calcium oxide (CaO) are the main components of inorganic part of human bones. Such synthetic nanocomposites could be very important implantable materials and using as substitute material for human hard tissues (bones and teeth). In this study, an aqueous sol-gel chemistry route has been developed to prepare nanostructured CHAp thin films on stainless steel substrate. For the preparation of thin films dip-coating and spin-coating techniques were used. The final samples were obtained by calcination of coatings for different time at 1000 °C. For the characterization of surface properties, the X-ray powder diffraction (XRD) analysis, scanning electron microscopy (SEM), atomic force microscopy (AFM) and the contact angle measurements were recorded.
Abstract: The study presented deal with preparation of batches of the system Y-Ba-Cu-O using sol-gel method and citric acid as precursor. Batches with particle size of 100 nm containing each of the phases Y123 and Y211 were prepared. The stoichiometric amounts of Y, Ba and Cu oxides were dissolved in 65% HNO3 until clear blue solution was observed under heating to 80 ̊С. The nitrate solutions obtained were neutralized to pH = 6 with 25% solution of NH3 (p.a.), then С6Н8О7 was added as the gels obtained were thermally treated. The transformation processes taking place under change of temperature were studied by IR, XRD, DTA and SEM.
Abstract: Application of modern ways of ceramic materials’ consolidation and association of synthesis methods of organic and inorganic chemistry, sol-gel method and mechanochemistry, allowing to control processes of synthesis of the defined phases at molecular level, gives the chance to create highly effective composite materials. It is known that properties of composites on the basis of refractory compounds become dimensionally dependent at reduction of the particles’ size to several interatomic distances in one, two or three dimensions . Obtaining of durable nanostructural ceramics on the basis of ZrO2 with substantial increase of mechanical properties can be realized by creation of material with fine homogeneous structure, on the basis of powders of nonoxygen compounds when strength properties and crack resistance increase at creation of –intra and –inter nanostructures. In work results of creation of the consolidated nanomaterials and composite ceramics with usage of the peculiarities set forth above for synthesis of precursors of powders and the defined phases that self-reinforce ceramic matrixes have been presented.
Abstract: Currently, there are several methods to produce spinel ferrite powder material such as sol-gel synthesis, self-propagating high-temperature synthesis (SHS), aerosol spray pyrolysis, and solution combustion synthesis (SCS). These methods have been shown to produce nominally phase pure ferrites for use in hydrogen generation by thermochemical water-splitting. Among these methods, the ferrites derived by SCS have not been fully investigated for hydrogen generation from thermochemical water-splitting. SCS, in general, has several advantages such as it being a simple synthesis that can be done relatively quickly and produces materials with high specific surface area. In this study, nickel, zinc, cobalt, and manganese ferrites were synthesized using SCS and analyzed by XRD, BET, and SEM. Each ferrite material was placed inside an Inconel tubular reactor and five consecutive thermochemical cycles to determine hydrogen production. The regeneration and water-splitting temperatures were performed with water-splitting and regeneration temperatures of 900°C and 1100°C, respectively. Nickel ferrite produced significantly higher average hydrogen volume as compared to the other ferrites over the five thermochemical cycles. However, all four ferrites showed a decrease in hydrogen volume generation with increase in consecutive water-splitting cycle, which could be due to the grain growth as observed by BET and SEM analyses.
Abstract: Self-cleaning and anti-fogging technology is already used in a variety of the products today, among which glazing products prevail. Their function is based on the two principles, either hydrophobic (Lotus effect) or photocatalytic hydrophilic principle. In the latter case, self-cleaning action is based on the combination of photocatalysis and photoinduced superhydrophilicity, where dirt removal by uniform spreading of water over the whole surface is improved with photocatalytic decomposition of organic contaminants. There is a big room to play and a huge potential to improve the properties of existing self-cleaning and anti-fogging surfaces by designing and tailoring new nanoarchitectures of the light-activated thin films. In this lecture we report about the latest achievements and relevance of nanostructured metal oxide surfaces for specific application in photocatalytic self-cleaning. The emphasis is given to the preparation and structure-property relationship of nanocomposite materials based on TiO2 (TiO2-SiO2) and ZnO (ZnO/Co3O4). The emphasis is given also to determination of photocatalytic self-cleaning activity by quantitative and sensitive methods such as fluorescence detection of the first degradation product of terephthalic acid.
Abstract: In this study, a ceramic water filter with micron sized pores was developed based on diatomite raw material. The slip with diatomite earth which has tubular shaped particles was prepared by using agar. Agar is a gelatinous material derived from sea alges and used as a gelling agent in order to form ceramic filters by gel casting method. Rheology of the slip was investigated by rheometry. In the forming process, polymer and metal molds were used instead of plaster molds. After de-molding, ceramic filter samples were dried and fired at 1200 °C/ h for 2 hours. Density, phase analysis and microstructure properties of porous diatomite based filter material were measured and characterized by He picnometer, XRD and SEM, respectively. Water filtration performance and microbiological test results were also investigated.
Abstract: Aerogels are porous materials with potential applications in fields ranging from thermal insulation, catalyst support, filters, electrical storage, components in optical devices, mechanical damping all the way to drug release. However, careful reliable characterization is the base for both, understanding of fundamental structure - property relationships as well as a directed development of materials and composites for specific applications. The review therefore addressed severe problem upon aerogel characterization that have been identified in the past and presents reliable non-destructive alternatives and novel methods that can be applied for the characterization of aerogels as well as their gel precursors.