196,189 research outputs found
Flower-like AuPtPd-Fe3O4 Nanocatalyst for Electrochemical Removal of Humic Acids and Cr(VI)
No full textA new nanohybrid for electrochemical removal of humic acids and Cr(VI)
No full textA new nanohybrid, based on flower‐like AuPtPd‐Fe3O4, has been designed and prepared through an easy and scalable synthetic approach for the effective and simultaneous removal of humic acids (HAs) and Cr(VI). The nanocatalyst, prepared in a one‐step procedure, consists of nanoparticles with a grain size of about 40 nm, constituted of a magnetite core ca. 20 nm and petals of PtPd and Au and, after a ligand exchange process, results dispersible in water. Calibration equations were plotted for the removal evaluation in water samples. Electrochemical tests were carried out at pH 3.0 and 30 mA. HAs were highly mineralized with TOC removal efficiency of 95% after only 3‐h electrolysis, while 99% of total chromium (Cr) was removed in 3 h. A mechanism was proposed to describe the catalyst activity. The nanocatalyst shows high removal performances for HAs and Cr(VI) even after 10 times treatment, indicating good stability
Laser damage threshold of SiO2 films by the photoacoustic Mirage technique
No full textAIP CP 463, edited by F. Scudieri and M. Bertolott
Simultaneous photoacoustic measurements of specific heat and thermal conductivity critical behaviour at a smectic A–nematic phase transition
No full textSimultaneous measurements of the thermal conductivity and specific heat at the smectic A-nematic phase transition in 4-n-octyl-4′-cyanobiphenyl (8CB) have been carried out with the photoacoustic technique. A critical increase in the thermal conductivity is reported. A critical decrease in the thermal diffusivity data confirms that the transition in 8CB is fluctuation dominated as also shown by the critical behaviour of the specific heat. © 1989 Taylor & Francis Group, LLC
Application of a front detection photopyroelectric configuration to the study of nonlinear effects in liquid crystals phase transitions
No full textThe aim of this paper is to present an experimental configuration which enables the use of the pyroelectric transducer in the front detection configuration. This configuration has been applied to the study of thermal parameters in the vicinity of two phase transitions of 9CB liquid crystal. Anomalies have been found in the phase of the photopyroelectric signal near the phase transitions. Strong nonlinear effects have been detected both in the 2ω signal amplitude and phase
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