Sustainable nickel catalyst for the conversion of lignocellulosic biomass to H2-rich gas

The objective of this paper was to design sustainable nickel catalysts supported on selected fly ash based zeolites to thermal processing of lignocellulosic feedstock towards hydrogen-rich gas. Moreover, in order to increase its catalytic performance in the studied process the catalyst supported on the most promising fly ash based zeolite was modified by selected rare-earth and transition metals (La, Pr, Ce, Y, Gd, Zr). The performed measurements exhibited that incorporation of nickel into the structure of zeolite A modified by lanthanum resulted in the most effective production of H₂. The characterization of its physicochemical properties (XRD, TPR, SEM-EDS, TPD-NH₃, BET and TGA-DTA) suggested that large pore size, moderate acidity, increased reducibility of an active phase and higher resistance to coke formation are the main factors responsible for increased activity of this catalyst.     

Derivatives of 1,4‐naphthoquinone as visible‐light‐absorbing one‐component photoinitiators for radical polymerisation

Bifunctional visible‐light photoinitiators for free radical polymerisation based on a 1,4‐naphthoquinone skeleton were synthesised and characterised using proton nuclear magnetic resonance spectroscopy and chemical ionisation mass spectrometry. Their basic spectroscopic properties, such as absorption and low‐temperature phosphorescence spectra, and their red‐ox properties were also measured. These initiators contain an appropriate electron/hydrogen donor group in the skeleton and do not require an additional coinitiator for initiation. During irradiation they act both as a triplet photosensitiser and as a hydrogen/electron donor. The ability of each naphthoquinone to act as a photoinitiator strongly depends on its chemical structure. These studies suggest that initiator radicals are generated from the triplet state in an intermolecular electron/hydrogen transfer reaction.     

Peculiar Role of the Metallic States on the Nano‐MoS2 Ceramic Particle Surface in Antimicrobial and Antifungal Activity

This study concerns the interactions of two chemically different materials hBN (covalent‐ionic bonds) and MoS₂ (covalent‐ionic and dispersive bonds) with bacteria and fungi. The materials used in the study were in the form of micro‐ and nanocrystals. Countable inactivation of microorganisms (Staphylococcus aureus, Sarcina lutea, Aspergillus niger, Escherichia coli) took place only in the case of MoS₂ nanosheets. The authors of the study suppose that the bioactivity of nano‐MoS₂ can be associated with the presence of “metallic states,” which are present only on their surface.     

OSCAT: Novel Technique for Time-Resolved Experiments Without Moveable Optical Delay Lines

Here, we present a novel technique for time resolved experiments without any moveable external delay line. Optical Sampling by Cavity Tuning (OSCAT) method is based on a femtosecond laser with a tunable repetition rate and a passive delay line. The time delay between the pump and probe pulses is determined by the repetition rate of the femtosecond laser.     

The effects of power characteristics on the heat transfer process in various types of motionless mixing devices

The main objective of this paper is to present the measurement results of the pressure drop and the heat transfer coefficient in the various types of static mixers. The experimental investigations are provided for the explanation of the influence of hydrodynamic conditions on the heat transfer enhancement for different static mixers. Based on the analysis of the experimental database and theoretical considerations, original formulas are proposed for the determination of the power consumption and the heat transfer in various types of motionless mixing devices. In this paper a new criterion is also defined which takes into consideration both the heat transfer process and hydrodynamic conditions. This criterion may be successfully applied to the selection of a static mixer for the heat transfer problems.     

A reduced order model of Molten Carbonate Fuel Cell: A proposal

The mathematical model of the Molten Carbonate Fuel Cell (MCFC) is presented. The new approach for modeling the voltage of MCFC is proposed. Electrochemical, thermal, electrical and flow parameters are collected in the 0-D mathematical model. The aim was to combine all cell working conditions in as a low number of factors as possible and to have the factors relatively easy to determine. A validation process for various experimental data was made and adequate results are shown. The presented model was validated for various fuel mixtures in relatively wide ranges of parameters. A distinction is made between the “design-point” and “off-design operation”.     

A Kerberized Architecture for Fast Re-authentication in Heterogeneous Wireless Networks

In this paper we present an architecture for fast re-authentication, based on the use of the Kerberos protocol, which allows the reduction in the latency introduced for an authentication process based on the Extensible Authentication Protocol (EAP) when providing network access in mobile networks. The architecture supports two modes of operation, proactive and reactive, to reduce the latency added for the authentication processes which is required when a mobile user changes network points of attachment. Moreover, we provide implementation details on a representative wireless testbed and obtain experimental results from the testbed. Those results are used for simulations to evaluate the performance of the proposed architecture for different deployment scenarios and parameters. We also provide a mathematical analysis to compute authentication delay and validate the simulation results. Performance comparison based on the experiment, simulation and analysis show that the proposed architecture can reduce the authentication delay, compared to other alternatives in typical deployment scenarios.