Deconvolution of Gas Diffusion Polarization in Ni/Gadolinium-Doped Ceria Fuel Electrodes

The deconvolution of physicochemical processes in impedance spectra of SOCs with nickel/ceria fuel electrodes is challenging as gas diffusion strongly overlaps with the electrochemical processes at fuel and air electrode. To overcome this issue, symmetrical cells were applied and the gas diffusion process at the fuel electrode was quantified by altering the inert component (nitrogen / helium) in a ternary fuel gas mixture. An effective gas transport parameter considering microstructural and geometrical features was derived, enabling a precise quantification of polarization resistances related to gas diffusion and hydrogen electrooxidation. The obtained values were applied to parameterize a dc cell model. The model validation in fuel cell and electrolyzer mode showed an excellent agreement between measured and simulated current/voltage characteristics over a wide range of technically meaningful gas compositions and operating temperatures.

Creation of thin films on the surface of InP with a controlled gas-sensitive signal under the influence of PbO + Y2O3 compositions

Thin-film objects with a reproducible temperature dependence of the resistance, thermally stable, and easy to obtain can be used as the sensitive elements in semiconductor gas sensors. The aim of this study was to create thin films on the InP surface under the influence of an oxide chemostimulator + inert component (PbO + Y2O3, respectively) compositions and to determine their gas-sensitive properties and their dependence on the formula of the composition.Thin films were synthesised on the InP surface by the method of chemically stimulated thermal oxidation under the influence of various PbO + Y2O3 compositions. The thickness of the formed films, their elemental and chemical composition were determined (by laser ellipsometry, X-ray phase analysis, and infra-red spectroscopy). A number of experiments were carried out to establish the gas-sensitive properties of the obtained films with respect to ammonia with concentrations of 120, 100, and 80 ppm.By chemically stimulated thermal oxidation, we obtained thin films with semiconductor properties on the InP surface. It was determined that the samples had n-type conductivity. A gas-sensitive response was detected in the presence of ammonia in the atmosphere. The ability to create thin films with a predetermined value of sensory response was demonstrated

Application of Silicon Dioxide as the Inert Component or Oxide Component Enhancer in ANFO

Non-ideal explosives with differing contents of silicon dioxide (silica or dioxosilane) added in the form of powder and gel were tested. Measurements of structure, crystallinity and morphology were performed by means of infrared spectroscopy (IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). IR and XRD analysis revealed a lack of SiO2 influence on the non-ideal explosive structure. SEM analysis indicated that all the surface deformations of ammonium nitrate(V) prill were filled by a thin fuel film layer on which SiO2 was present. The additional calculations of selected theoretical properties of non-ideal compositions were made using ZMWCyw software. Based on this, it was established that the optimum semimetal content was 1.0 wt.%. Blasting tests confirmed that the addition of 1.0 wt.% SiO2 to the Ammonium Nitrate Fuel Oil (ANFO) resulted in the lowest volume of post-blast fumes. Moreover, it was established that finer SiO2 powder cannot be used as the oxide component enhancer due to the inhibition of detonation reaction. SiO2 should be used only as an inert component.

STUDY OF PROPERTIES OF DIFFUSION-HARDENING COMPOSITE SOLDER GASN-CUSN-MO

В статье обсуждается возможность регулирования свойств диффузионнотвердеющего припоя (ДТП) на основе легкоплавкого сплава галлий-олово и твердой компоненты состоящей из порошка сплава медь-олово посредством введения инертного порошка металлического молибдена и термической обработки. Оценена микротвердость и термическая устойчивость композиционных диффузионнотвердеющих припоев. Показано, что повторная термическая обработка при высоких температурах способствует переходу припоя в равновесное состояние, при этом происходит резкое увеличение твердости, почти на порядок. Подтверждено, что инертные наполнители снижают механическую прочность относительно начального диффузионно-твердеющего припоя, даже те, которые хорошо смачиваются галлием, однако существует некий диапазон, содержащий определенное количество инертного компонента, у порошка молибдена это 15 %, при котором микротвердость композиционного припоя выходит на максимум. The article discusses the possibility of regulating the properties of a diffusion-hardening solder based on a low-melting gallium-tin alloy and a solid component consisting of a copper-tin alloy powder by introducing an inert metal molybdenum powder and heat treatment. The microhardness and thermal stability of composite diffusion-hardening solders were evaluated. It is shown that repeated heat treatment at high temperatures contributes to the transition of the solder to an equilibrium state, with a sharp increase in hardness, almost by an order of magnitude. It is confirmed that inert fillers reduce the mechanical strength relative to the initial diffusion-hardening solder, even those that are well wetted with gallium, but there is a certain range containing a certain amount of the inert component, for molybdenum powder it is 15 %, at which the microhardness of the composite solder reaches the maximum.

Experimental Investigation of Reactive-Inert Particulate Matter Detachment from Metal Fibres at Low Flow Velocities and Different Gas Temperatures

The detachment of particle structures from single fibres in gas flow has been investigated only for inert particle structures yet. This study investigates the detachment of particle structures containing reactive components. These reactive components disappear during the reaction and enhance detachment at low flow velocities. Soot was used as the reactive component and glass spheres as the inert component of the particle structure. The soot disappears due to combustion with oxygen leaving only the glass spheres on the fibre. Without reaction, the detachment phenomenon was observed at superficial flow velocities above 1.9 m/s and with reaction at 0.5 m/s. This shows that reacting and disappearing components of the particle structure can enhance detachment.

Synthesis of nano-dimensional cobalt-zinc ferrites by the low-temperature spray-drying with subsequent thermolysis

Co0,65Zn0,35Fe2O4nanoparticles were produced by spray-drying in air in presence of NaCl from the solution of nitrates, as well as from the suspension of coprecipitated particles. The precursors obtained were annealed at 300–900 °C in the matrix of the inert component in order to increase the crystallinity degree without substantial increase of the nanoparticle size. Microstructure, morphology and magnetic properties of nanoparticles were studied by XRD, FT-IR spectroscopy, TEM / SEM and magnetometry. For the ferrites obtained from nitrate solutions partial oxidation of Co2+ions to Co3+occurs, which leads to the formation of two spinel phases, ferrite and cobaltite. With the increase of annealing temperature the content of cobaltite decreases and content of ferrite increases. No cobaltite formation was observed for annealing the spray-dried suspension. An increase in the temperature of the heat treatment leads to partial recrystallization of the particles and the ordering of the ferrite crystal structure, which causes an increase in the specific magnetization of the materials: from 32.8 emu/g (before annealing) to 91.3 emu/g (annealing at 900 ° C). The average diameter of nanoparticles after heat treatment does not exceed 100 nm.

The Combustion and Emissions Performance of a Syngas-Diesel Dual Fuel Compression Ignition Engine

Remote communities in Canada heavily rely on reciprocating diesel generators for heat and power generation. These engines utilize diesel fuel that is imported at great expense and generate green-house gas (GHG) and pollutant emissions. Replacing diesel fuel in these engines by syngas derived from a thermo-chemical treatment of local renewable biomass can not only lower the fuel cost but also reduce GHG and pollutant emissions for remote communities. Besides, syngas-diesel dual fuel combustion can maintain the ability to revert back to diesel operation and therefore ensure reliable heat and power supply when syngas is not available. In this study, the combustion and emissions performance of a syngas-diesel dual fuel engine was investigated at low and medium loads. A single cylinder direct injection diesel engine was modified to operate using a dual fuel strategy. The diesel fuel was directly injected to the cylinder, while syngas was injected into the intake port. The effects of syngas fraction and composition on energy efficiency, cylinder pressure, exhaust temperature, and combustion stability were recorded and analyzed. The emissions data, including PM, NOx, CO, and unburned hydrocarbon, were also analyzed and reported in the paper. The results suggest that the substitution of diesel by a syngas caused a slight decrease in brake thermal efficiency and an increase in CO emissions. The effect of a syngas on soot emissions depended on the composition and/or quality. The inert component content of a syngas significantly affected NOx emissions in a syngas-diesel dual fuel internal combustion engine.