Authors:Anca Moanţă, Cătălina Ionescu, P. Rotaru, Margareta Socaciu, and Ana Hărăbor
Using the Williamson method, a new dye 4-[(4-chlorobenzyl)oxy]-3,4′-dichloroazobenzene (CODA) with liquid crystalline properties was synthesized. The structure and the thermal behavior of CODA were investigated by means of nuclear magnetic resonance, X-ray diffraction, differential scanning calorimetry, and light polarized optical microscopy techniques. The thermophysical processes were monitored by heating–cooling cycles, but the formation of liquid crystal phases were exhibited only for small values of the cooling rates. For the first heating–cooling cycle, the melting and the solidification processes, thus the characteristic temperatures, are shifted to higher values when compared to the following cycles.
Authors:A. E. Cioablă, G. Trif Tordai, P. Rotaru, Margareta Socaciu, and Ioana Ionel
This article studied two sorts of biomass (corn and beech sawdust) and two varieties of coal (bituminous coal and lignite), which can produce energy using two different technologies: co-firing and anaerobic fermentation in pilot installations, in order to determine the future perspectives of those materials for large scale applications. By thermal analysis, the thermochemical characteristics of biomass (corn and beech sawdust) and of coal (bituminous coal from Jiu Valley and lignite from Oltenia basin) were determined. The co-firing tests have been achieved at a ratio of 15 % biomass, the rest being coal. At biomass–coal co-firing, the SO2, NOx, CO, CO2 and fly ash concentrations in the flue gases is lower than the burning of fossil fuels. In the anaerobic fermentation of biomass, the maximum concentration of methane inside the produced biogas was 50–55 % by volume in the beech sawdust batch and 67–68 % by volume in the corn batch.
Authors:A. Rotaru, Catalin Constantinescu, P. Rotaru, Anca Moanţâ, M. Dumitru, Margareta Socaciu, Maria Dinescu, and E. Segal
A new synthesized 4CN type azomonoether, exhibiting dying properties, crystalline nature and generating interest as a material
for non-linear optical applications was investigated. Modern devices incorporating liquid crystals tend to use thin films
of such materials because of their special characteristics. Thermal stability studies are indispensable before attempting
any deposition experiment.
We have investigated the thermal behaviour of 4-[(4-chlorobenzyl)oxy]-4′-cyano-azobenzene (TG, DTG, DTA and DSC) in inert
flow atmosphere, under non-isothermal conditions. The phase transitions were studied by repeated heating-cooling regimes,
with intercalated isothermal steps. The thin films were deposited on silicon and quartz substrates by matrix assisted pulsed
laser evaporation (MAPLE) using a Nd:YAG laser working at 266 nm. FTIR spectroscopy of the obtained thin films confirmed the
preservation of the compound’s structure.