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Abstract The direct carbon fuel cells with solid oxide electrolyte (DC-SOFC) and anodes deposited by inject printing (EM/DCIJP) were studied. The cells were fed with carbon fuel obtained by the direct RF plasma splitting of methane. Since the (EM/DCIJP)M/DCIJP technology allows easy modification of electrode material, the effect of Cu addition to the Ni–YSZ anode was investigated. The significant improvement of the cell performance with the new anode was observed.

Ceramic carbon electrodes were prepared via polymerization of silane materials containing sulfonic acid groups in the presence of Pt/Vulcan XC72. Cyclic voltammetry and electrochemical impedance spectroscopy were used to investigate the effects of sulfonic acid functionalities on platinum utilization and proton conductivity, as well as CCE microstructure. It has been determined that incorporation of small amounts of sulfonated silane to the CCE structure can lead to a profound enhancement of proton conductivity despite decreases in BET surface area. Retention of surface area was achieved through combination of sulfonated and unsulfonated organosilane precursors. These composite samples show improved performance during fuel cell testing than for CCEs prepared using unsulfonated precursors.

AbstractIn this manuscript we reply to the issues raised by G. Bagheri and C. Bonadonna in their comment 2019JB017697. We reiterate our definition of particle Reynolds number, which is appropriate for our data set of experimental measurements, and we show that the poor performance of Bagheri and Bonadonna (2016, https://doi.org/10.1016/j.powtec.2016.06.015) model discussed in Dioguardi et al. (2018, https://doi.org/10.1002/2017JB014926) was mainly due to the typos in the equations presented in their original manuscript. We believe that the iterative methodology for calculating the drag coefficient is not strictly necessary for our data set. In this reply, however, we also include results of the intercomparison study among different drag models using the iterative methodology. Results show that the performance of the different drag models considered in the intercomparison study is not significantly affected by the employed methodology (direct vs. iterative) and that, regardless the employed methodology and unlike what has been stated in the comment 2019JB017697, our model has the best performance in reproducing the experimentally measured terminal velocities.

Abstract Various assumptions are often made to model turbomachinery bladed assemblies. In particular, the cyclic symmetry of single rotor stages, and dynamically independence of isolated rotor stages are frequently used. The first assumption enables a drastic reduction of the required computational resources by considering only one sector instead of the entire assembly to model and analyze the dynamic behavior of the complete structure. However, small random blade-to-blade structural variations, known as mistuning, exist due to manufacturing tolerances, etc. and significantly affect the dynamic behavior of bladed disks. The second assumption also reduces the needed computational resources and time. However, ignore inter-stage coupling does not always describe accurately the disk or drum flexibility especially at the inter-stage boundaries. In this work, the component mode mistuning method is used for multi-stage assemblies to create a mistuning identification approach. An experimental modal analysis is performed on a two-stage monobloc academic bladed drum. The frequency response function is measured using a base excitation with an electrodynamic shaker and one measurement point per blade of each stage is used. The approach is used to identify mistuning in a multi-stage rotor. Numerical and experimental results are presented. Results show that the proposed approach is effective even for modes which are multi-stage.

A description is given of how accurate system modeling of a DC system with an electromagnetic transient simulation program can be used to study and correct interbipole oscillations between converters connected into a parallel multiterminal system. The authors show how too decide on the details of the modeling that is required and demonstrate that it is often not enough to use prepackaged, generic HVDC control models supplied with these programs. The details of control models that are used in electromagnetic simulation programs are shown to have a significant impact, in some cases, on the simulation results. In particular, a case of 6 Hz oscillations, in the DC current of two converters of the Nelson River System, is accurately simulated, and it is shown that control modifications suggested by the simulation actually do eliminate the interbipole oscillations. >

This study is to our knowledge the first to describe the effect of a Gas-Gas Heater (GGH) of a coal fired power plant's has on (i) the H2SO4 concentration and (ii) the particle/aerosol number concentration and particle size distribution present in the flue gas. In the absence of a GGH, homogenous nucleation takes places inside the Wet Flue Gas Desulphurisation (WFGD) converting the gaseous H2SO4 into aerosol H2SO4. This leads to a high aerosol number concentration behind the WFGD with 80% of the aerosols being smaller than 0.02 μm. This implies that an amine based carbon capture (CC) installation treating this flue gas can suffer from amine mist formation due to the high amount of available nuclei (i.e., H2SO4 aerosols) resulting in high amine emissions. In contrast, in the presence of a GGH not only 70% of the H2SO4 is removed from the flue gas (measured at the Nijmegen powerplant), but also homogenous nucleation in the WFGD is prevented resulting in low particle number concentrations. The flue gas leaving the GGH will not create any mist formation issues in an amine based CC installation due to the low amount of nuclei present in the flue gas. It is not the reduction in H2SO4 concentration by 70% inside the GGH as such that prevents mist formation but absence of H2SO4 in its aerosol form. These results are most likely quite widely transformable to other power plants that burn low sulfur coal i.e., around 0.7 weight%. This information will serve future pilot and demo CC installation around the world; in particular when retrofitted on power plants that have a GGH.

A preliminary evaluation of the performance characteristics for three types of rechargeable, ‘AA’ size, lithium cell chemistries, namely Li/TiS2 (two different manufacturers), Li/MoS2 and Li/MnO2, was carried out in order to determine their potential usefulness in the internal (implanted) battery for the electrohydraulic ventricular assist device (EVAD) being developed. The major parameters studied at 37 °C were discharge rate capability, self-discharge and cycle life. The cycle life of the lithium cells above the minimum 30 min discharge time specified for EVAD were short, with the Li/MoS2, Li/MnO2 and two Li/TiS2 cells giving 80, ∼ 11, 37 and 101 cycles, respectively, under pulsed discharge conditions. The 24 H, self-discharge study of all the cells at 37 °C showed < 1.2% decrease in capacity. Discharge rate studies showed that the Li/TiS2 cells from both manufacturers offered higher observed specific energies (85 and 133 W h/kg) and energy densities (203 and 273 W h/l), lower internal resistances (155 and 84 mΩ) and larger observed capacities (0.83 and 1.00 A h) when compared to the Li/MoS2 (49 W h/kg, 126 W h/l, 153 mΩ and 0.58 A h, respectively) and Li/MnO2 (56 W h/kg, 131 W h/l, 350 mΩ and 0.39 A h, respectively) cells operating under average EVAD load conditions. The cycle life and operating times of cells that were pulse discharged to mimic actual EVAD operating conditions were shorter than those that underwent cycling with an average EVAD load. When compared to other energy sources and the EVAD design specification, it was concluded that none of these prototype lithium cells were currently suitable for use in the EVAD due to their low cycle life.

Use of a pilot-scale fixed-film bioreactor was investigated for remediation of bromate contamination within groundwater. Bromate reduction with stoichiometric production of bromide was observed, providing supporting evidence for complete reduction of bromate with no production of stable intermediates. Reduction of 87-90% bromate from an influent concentration of 1.1 mg L(-1) was observed with retention times of 40-80 h. Lower retention times led to decreases in bromate reduction capability, with 11.5% removal at a 10 h retention time. Nitrate reduction of 76-99% from a 30.7 mg L(-1) as NO(3)(-) influent was observed at retention times of 10-80 h, although an increase in nitrite production to 2.7 mg L(-1) occurred with a 10 h retention time. Backwashing was not required, with the large plastic packing media able to accommodate biomass accumulation without decreases in operational efficiency. This study has provided proof of concept and demonstrated the potential of biological bromate reduction by fixed-film processes for remediation of a bromate contaminated groundwater source.