Mathematical modeling of temperature effect on algal growth for biodiesel application

Microalgae biomass is promising feedstock for the industrial production of biodiesel. Hence, research and development are required in various domains especially optimizations of growth conditions including temperature effect for mass scale operation (production of biomass, harvesting, extraction of lipid, etc). Since in middle east region, seasonal temperature variation and more rapid daily fluctuations are amenable to alter the growth kinetics of microalgae in outdoor culture and hence affect algae biomass production efficiency. Therefore, in this study, a mathematical model was developed to calculate how the algae sp. (Chlorella kessleri) will react at different temperatures. The model integrates Monod model and Arrhenius equation, and as such it describes the relationship of algal growth rate with culturing temperature and limiting nutrient concentration. The apparent activation energy and pre-exponential factors were calculated to be 2537 cal/mol and 0.0077 day−1, respectively. The developed models could be useful to anticipate the effective impacts of temperature on outdoor algae culture

Potentiodynamic polarization studies of Cefadroxil and Dicloxacillin drugs on the corrosion susceptibility of aluminium AA6063 in 0.5 M nitric acid

The inhibition effectiveness of Cefadroxil (C) and Dicloxacillin (D) drugs on aluminium in0.5 M nitric acid solution have been holistically studied using potentiodynamic polarizationtechniques, weight loss measurements, computational studies and structural character-ization. The structural characterizations were carried with the aid of scanning electronmicroscope equipped with energy dispersive spectrometer (SEM/EDS), optical microscope(OPM) and XRD. Potentiodynamic polarization test revealed the corrosion protectivenessand adsorbing ability of Cefadroxil and Dicloxacillin drugs on aluminium (Al). The mixedinhibitive characteristics of Cefadroxil and Dicloxacillin drugs were confirmed through theTafel plot, which further established their predominant effect on the anodic reaction asa result of Ecorrvalue shift to more positive sides. The combined effect of Cefadroxil andDicloxacillin drugs reduced the exchange in current density and corrosion rate drasticallyfrom 484 �A/cm2to 199 �A/cm2and 0.4502 mm/year to 0.2152 mm/year respectively. 44.4%increase in microhardness was achieved and Inhibition efficiency of 58.9% was accom-plished

Study of the sensitisation process of a duplex stainless steel (UNS 1.4462) by means of confocal microscopy and localised electrochemical techniques

When duplex stainless steels are heated, they can become sensitised and intermetallic phases can appear. In this work, samples of duplex stainless steel, UNS 1.4462, have been heated (850 degrees C for 1 and 2 h) in a heating unit that can be accommodated to a confocal microscope in order to study the morphological changes in-situ. The electrochemical behaviour of the samples has been analysed by means of conventional and localised electrochemical techniques. According to the results, there is a general decrease in the steel resistance to localised corrosion; this decrease can be related to defects in the formed passive film.We wish to express our gratitude to MICINN (CTQ2009-07518), to Universitat Politecnica de Valencia (CEI-01-11), to the Generalitat Valenciana for its help in the CLSM acquisition (MY08/ISIRM/S/100), to Professor Alda Simoes and Andreia Marques for the help on LEIS measurements and to Dr. Asuncion Jaime for her translation assistance.Leiva García, R.; Fernandes, JS.; Muñoz-Portero, M.; Garcia-Anton, J. (2015). Study of the sensitisation process of a duplex stainless steel (UNS 1.4462) by means of confocal microscopy and localised electrochemical techniques. Corrosion Science. 94:327-341. https://doi.org/10.1016/j.corsci.2015.02.016S3273419