Evaluation of elastic properties of DLC layers using resonant ultrasound spectroscopy and AFM nanoindentation

Elastic properties of diamond-like carbon (DLC) layers with gradient carbon–silicon interlayer were studied by resonant ultrasound spectroscopy (RUS) and standard nano-indentation technique. The DLC layers were prepared by pulsed laser deposition on SiC/Si substrates. The RUS method is based on modal analysis of the specimen vibration. The resonant frequency shifts caused by the layer are for the evaluation of the dynamic in-plane elastic properties of the deposited DLC. The results were compared with the quasi-statical quantities — Young's modulus and hardness, obtained by nanoindentation using the AFM tip.     

Sorption of some metal cations by a modified biopolymer based on the mycelium of Penicillium chrysogenum

Summary Three types of a modified biopolymer based on the mycelium of Penicillium chrysogenum were evaluated as to their sorption characteristics for Hg²⁺, Pb²⁺, Cu²⁺ and Cd²⁺. Their useful and total sorption capacities were calculated from their respective breakthrough curves. The highest sorption capacity was recorded for Hg²⁺. Evidence is presented that the retained metals can be easily eluted with diluted mineral acids.     

Anodic oxidation of o-toluenesulphonamide to saccharine on a NiO(OH)-coated nickel anode

o-Toluenesulphonamide has been electrolytically oxidized at low current density to saccharine in aqueous solutions of alkali carbonates on anodes coated with NiO(OH). This electrolytic oxidation led to a 40% yield of saccharine. The application of carbon and glassy-carbon counter electrodes or of various supports for the working electrodes did not result in improved saccharine yield. Moreover, the choice of a different potential and a different current density or the use of organic co-solvents did not substantially affect the course of the electrolytic oxidation.In the electrolytic oxidation ofo-toluenesulphonamide a parasitic evolution of oxygen occurred which caused a partial degradation of the starting material. In strongly alkaline media, i.e. in aqueous solutions of alkali hydroxides, a fission of the NH₂ group with formation ofo-toluenesulphonate occurred during the electrolysis.     

Electrolytical reduction of maleinamide and fumaramide of 2-nitrobiphenyl-2′-amine at mercury electrodes

The role played by geometric isomerism in the intramolecular cyclization reaction initiated by the electrode reduction of maleinamide and fumaramide of 2-nitrobiphenyl-2′-amine was studied at mercury electrodes. The cyclization reaction leading to the formation of benzo(c)cinnoline occurs with the former substance whereas only a reduction of the nitro group and of the CC double bond could be observed with the latter.     

Metallographic examination and reconstruction of the 6th century lombardic sword from Kyjov

ABSTRACT

A Lombardic cemetery dating to the late Migration Period was excavated at Kyjov (Czech Republic) in 2010, and inter alia a warrior’s grave no.881, which had never been looted, was uncovered there. The burial included a sword, which was subjected to a detailed conservation survey and then to metallographic examination. Further technological information was obtained by the production of a replica of the sword. The weapon can be characterized as a pattern-welded sword, with cutting edges and an inner core of steel. Construction and heat treatment of the sword are discussed in a broader context of 5th–7th century swords and sword-making. Experimental reconstruction of the sword shows that historical pattern-welded composites reveal a clear pattern after being exposed to controlled corrosion in vinegar vapor.     

Heat Integration retrofit analysis—an oil refinery case study by Retrofit Tracing Grid Diagram

Heat Integration has been established over the last decades as a proven chemical engineering methodology. Two design implementations are often used in the industry: grassroots and retrofit. Although various methods have been developed for retrofit, it still needs more development to ensure simultaneously thermodynamic feasibility and economic viability. In this paper, a novel graphical approach has been developed to facilitate the understanding of the current situation and scope of improvement. The Retrofit Tracing Grid Diagram presents all streams and heat exchangers in temperature scale and the heat exchangers are clearly separated from each other, enabling clear visualisation of the current state. The tool incorporates the previously developed Cross-Pinch Analysis as well as path approach for retrofit. Additionally, the non-vertical heat transfer can be evaluated. The application of the developed tool has been validated on an oil refinery case study. The applicability of the tool is evident as it can reveal additional options for modification that none of the previous methods considered.     

Mechanisms and strategies for ash deposition reduction in flue gas heat exchanger

Clean Technologies and Environmental Policy - Ash deposition in flue gas heat exchanger affects its heat transfer performance and lifecycle, which becomes a crucial factor restricting the efficient...     

Advancing low-carbon emissions in Asia: mitigation of greenhouse gases and enhancing economic feasibility for major sectors

Clean Technologies and Environmental Policy -