The aim of this work was to prepare gold nanoparticles from gold scrap by using Ultrasonic Spray Pyrolysis (USP).USP is an innovative and powerful tool for the synthesis of particles with controlled and uniform particle size. The mechanism of gold nanoparticles` synthesis by USP was realized by an investigation of the reactions parameters and morphological characteristics of obtained Au nanoparticles. The experimental investigations were performed by an ultrasonic source of 0.8 and 2.5 MHz, acting in a mixture of chloric/nitric acid and by forming aerosols with constant droplet sizes. The droplet's size depends on the characteristics of the formatted solution and the frequencies of the ultrasound. Subsequent thermal decomposition of the aerosol droplet was performed in a hydrogen and nitrogen atmosphere between 300 and 800 °C. With the experimental production five different fractions of gold nanoparticles were obtained. For the microstructure characterisation of Au nanoparticles the following techniques were used: SEM and TEM microscopies, and EDX analysis.
B.04 Guest lecture
COBISS.SI-ID: 15322902Numerical analysis is performed to examine the heat transfer of colloidal dispersions of Au nanoparticles in water (Au nanofluids). The analysis used a two-dimensional enclosure under natural convection heat transfer conditions and has been carried out for the Rayleigh number in the range 10(exp3)(Ra(10(exp5), and for the Au nanoparticles` volume fraction range 0(fi(0.10. We report highly accurate numerical results which indicate clearly that the mean Nusselt number is an increasing function of both, Rayleigh number and volume fraction of Au nanoparticles. The results also indicate that heat transfer enhancement is possible using nanofluids in comparison to conventional fluids. However, low Rayleigh numbers show more enhancement compared to high Rayleigh numbers.
B.04 Guest lecture
COBISS.SI-ID: 15537686On the TV evening the development of production techniques for synthesis of Au nanoparticles with well-defined size, shape and composition was presented. This science field is namely the important filed in nanotechnology. Au gold nanoparticles are namely very attractive because of their potential use in electro-chemistry and medicine such like for production different nano-devices.
F.18 Transfer of new know-how to direct users (seminars, fora, conferences)
COBISS.SI-ID: 14940694