University of Patras

About: University of Patras is a education organization based out in Pátrai, Greece. It is known for research contribution in the topics: Population & Catalysis. The organization has 13372 authors who have published 31263 publications receiving 677159 citations. The organization is also known as: Panepistímio Patrón.

Lipid production by yeasts growing on biodiesel‐derived crude glycerol: strain selection and impact of substrate concentration on the fermentation efficiency

Abstract: Aims To screen yeasts in relation to the potential to produce single cell oil (SCO) from biodiesel-derived glycerol and to enhance SCO production in Lipomyces starkeyi and Rhodosporidium toruloides yeasts. Methods and results Yarrowia lipolytica, Cryptococcus curvatus, R. toruloides and L. starkeyi were grown in nitrogen-limited flask cultures. Yarrowia lipolytica strains produced citric acid and mannitol. Lipomyces starkeyi DSM 70296 and R. toruloides NRRL Y-27012 showed potential for SCO production, and were cultivated at increasing the initial glycerol concentrations with the initial nitrogen concentration remaining constant. Significant biomass and SCO production were reported even in cultures with high initial glycerol concentrations (i.e. 180 g l(-1) ). Lipid quantities of c. 12 g l(-1) (lipid in dry cell weight 35-40%) were obtained for both L. starkeyi and R. toruloides, quite high values compared with literature values for oleaginous micro-organisms growing on glycerol. However, these strains exhibited different kinetic profiles in the synthesis of intracellular polysaccharides. Lipomyces starkeyi produced a significant quantity of polysaccharides (c. 7 g l(-1) ). The yeast lipids contained mainly oleic and palmitic and to a lesser extent linoleic and stearic acids. Conclusions Lipomyces starkeyi and R. toruloides are potential SCO producers from crude glycerol. Significance and impact of the study Very scarce numbers of reports have indicated the production of SCO by L. starkeyi and R. toruloides growing on glycerol. We report here that these yeasts are able efficiently to convert raw glycerol into SCO, while L. starkeyi also synthesizes intracellular polysaccharides in marked quantities.

Cyanographene and Graphene Acid: Emerging Derivatives Enabling High-Yield and Selective Functionalization of Graphene

Abstract: Efficient and selective methods for covalent derivatization of graphene are needed because they enable tuning of graphene’s surface and electronic properties, thus expanding its application potential. However, existing approaches based mainly on chemistry of graphene and graphene oxide achieve only limited level of functionalization due to chemical inertness of the surface and nonselective simultaneous attachment of different functional groups, respectively. Here we present a conceptually different route based on synthesis of cyanographene via the controllable substitution and defluorination of fluorographene. The highly conductive and hydrophilic cyanographene allows exploiting the complex chemistry of −CN groups toward a broad scale of graphene derivatives with very high functionalization degree. The consequent hydrolysis of cyanographene results in graphene acid, a 2D carboxylic acid with pKa of 5.2, showing excellent biocompatibility, conductivity and dispersibility in water and 3D supramolecular asse...

Surface, grain-boundary and interfacial energies in Al2O3 and Al2O3-Sn, Al2O3-Co systems

Abstract: Using the multiphase equilibrium method for the measurement of contact angles, the surface and grain-boundary energies of polycrystalline Al2O3 in the temperature range of 1473 to 1923 K were determined. Linear temperature functions were obtained by extrapolation for both quantities between absolute zero and the melting point of Al2O3. The temperature dependence of the surface and grain boundary energies can be expressed as $$\gamma _{{\rm A}l_2 O_3 } = 2.559 - 0.784 \times 10^{ - 3} T(J m^{ - 2} )$$ and $$\gamma _{{\rm A}l_2 O_3 - Al_2 O_3 = } 1.913 - 0.611 \times 10^{ - 3} T(J m^{ - 2} )$$ respectively. The interfacial energies of Al2O3 in contact with the molten metals tin and cobalt revealed a linear dependence on temperature.

On industrial learning and training for the factories of the future: a conceptual, cognitive and technology framework

Abstract: The manufacturing education addresses significant challenges in view of paving the way for the human capital of the Factories of the Future. This paper introduces a specification framework for the delivery of industrial learning and training, addressing the needs for the "knowledge" workers of the factories of the future. A review of the relevant background, including the activities associated with the industrial learning and its basic methods as well as some emerging paradigms, is first provided. A Teaching Factory based paradigm is then suggested as the conceptual foundation of this framework. A cognitive framework, addressing the major building blocks of the industrial learning process, namely the attitude the knowledge the skills and the competences is being defined. An appropriate technology framework, dealing with the needs of engineers and blue-collar workers, for practising the manufacturing knowledge content within digital environments, is suggested at this point. Finally, the approach of the future implementation of the specific framework is being discussed.