In-situ sub-structure decoupling of resiliently coupled assemblies

The context of this paper is the increasing need for vibro-acoustic simulation across many sectors. A procedure is derived for decoupling the components of resiliently mounted assemblies. An independent characterisation of the components is obtained such that they can be mathematically recombined with other elements to form virtual assemblies or Virtual Acoustic Prototypes. Unlike standard decoupling procedures, the proposed approach does not require the assembly to be physically decoupled at any stage. It is argued that this offers significant advantages in terms of convenience and, importantly, representativeness. The boundary conditions within a physically coupled assembly are realistic by definition, which may not be the case for physically decoupled components. The procedure is validated numerically using a lumped parameter model and demonstrated experimentally through several case studies. Keywords: In-situ, measurement, experimental,free-interface, decoupling, FRF, sub-structure, structural, characterisatio

Direct observation via in situ heated stage EBSD analysis of recrystallization of phosphorous deoxidised copper in unstrained and strained conditions

Recrystallization of phosphorous deoxidised copper used for strength critical applications at elevated temperatures was investigated by means of in situ heated stage EBSD analysis using a Gatan Murano heated stage mounted within a Carl Zeiss Sigma FEGSEM electron microscope. The influence of applied strain as the result of deformation within a Nakajima test as an analogue for industrial forming on the recrystallization temperature was investigated, the impact of increased heating rates on microstructural evolution was also investigated. Inverse pole figure plots combined with regions of reduction in local misorientations and variations in geometrically necessary dislocations were used to establish the point of recrystallization and the recrystallized fraction of the material. Recrystallization was observed to occur at temperatures as low as 130 °C in highly strained samples compared to around 300 °C within the annealed samples dependent upon heating rate. Increased heating rates were observed to produce a finer final grain structure but had little effect on presence of 60° grain twins, which was influenced more by initial material condition

In situ elucidation of the active state of Co-CeOx catalysts in the dry reforming of methane: the important role of the reducible oxide support and interactions with cobalt

The dry reforming of methane was systematically studied over a series (2-30 wt%) of Co (~5nm in size) loaded CeO2 catalysts, with an effort to elucidate the behavior of Co and ceria in the catalytic process using in-situ methods. For the systems under study, the reaction activity scaled with increasing Co loading, and a 10 wt% Co-CeO2 catalyst exhibiting the best catalytic activity and good stability at 500 °C with little evidence for carbon accumulation. The phase transitions and the nature of active components in the catalyst were investigated during pretreatment and under reaction conditions by ex-situ/in-situ techniques including X-ray diffraction (XRD) and ambient-pressure X-ray photoelectron spectroscopy (AP-XPS). These studies showed a dynamical evolution in the chemical composition of the catalysts under reaction conditions. A clear transition of Co3O4 → CoO → Co, and Ce4+ to Ce3+, was observed during the temperature programmed reduction under H2 and CH4. However, introduction of CO2, led to partial re-oxidation of all components at low temperatures, followed by reduction at high temperatures. Under optimum CO and H2 producing conditions both XRD and AP-XPS indicated that the active phase involved a majority of metallic Co with a small amount of CoO both supported on a partially reduced ceria (Ce3+/Ce4+). We identified the importance of dispersing Co, anchoring it onto ceria surface sites, and then utilizing the redox properties of ceria for activating and then oxidatively converting methane while inhibiting coke formation. Furthermore, a synergistic effect between cobalt and ceria and the interfacial site are essential to successfully close the catalytic cycle.Peer ReviewedPostprint (author's final draft

In-situ Co2 Current Efficiency Measurement of Direct Ethanol Fuel Cell

In this present work, we carry out systematically study on catalyst for ethanol electrooxidation in direct ethanol fuel cell. For cathode catalyst we use a commercial catalyst of 40% Pt/C from ETEK. Catalysts were printed on to carbon paper of TGPH 060 and sandwiched into membrane electrode assembly (MEA) and then arranged in fuel cell with the geometric area 1.2 cm2. As an electrolyte, we used Nafion 117 from Du Pont. On-line Differential Electrochemical Mass Spectrometry (DEMS) measurement in fuel cell setup was carried out in order to determine the activity and selectivity which was indicated by result of Faradaic current and CO2 current efficiency of ethanol electro-oxidation respectively. PtRhCeO2/C was significantly improve the selectivity to form of CO2 in comparison to the commercial catalyst of 20% Pt/C from Alfa Aesar- Johnson Mattews . Increasing of selectivity is shown by increase of CO2 current efficiency of ethanol oxidation of about 25 percent in comparison to references catalyst of 20% Pt/C Alfa Aesar-J