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The catalytic active sites of NiFe and NiFeCr (oxy)hydroxides are revealed byoperandospectroscopic techonologies for alkaline water oxidation.

Abstract To achieve optimal generation from a number of mixed power plants by minimizing the operational cost while meeting the electricity demand is a challenging optimization problem. When the system involves uncertain renewable energy, the problem has become harder with its operated generators may suffer a technical problem of ramp-rate violations during the periodic implementation in subsequent days. In this paper, a scenario-based dynamic economic dispatch model is proposed for periodically implementing its resources on successive days with uncertain wind speed and load demand. A set of scenarios is generated based on realistic data to characterize the random nature of load demand and wind forecast errors. In order to solve the uncertain dispatch problems, a self-adaptive differential evolution and real-coded genetic algorithm with a new heuristic are proposed. The heuristic is used to enhance the convergence rate by ensuring feasible load allocations for a given hour under the uncertain behavior of wind speed and load demand. The proposed frameworks are successfully applied to two deterministic and uncertain DED benchmarks, and their simulation results are compared with each other and state-of-the-art algorithms which reveal that the proposed method has merit in terms of solution quality and reliability.

Abstract With recent developments in the design and manufacturing process of water-based fire suppression systems , more advanced technologies such as water mist systems have expanded in their building application. In this article, the critical fire suppression mechanisms of water mist systems and conventional fire sprinklers are investigated and compared, with emphasis on the influence of water droplet sizes on the fire suppression mechanisms. Applying computational fluid dynamics (CFD), a fully ventilated fire compartment room has been considered where a methane pool fire was placed at the centre. The considered fire suppression systems were placed directly upon the fire. Thermocouple and gas probes were applied in the computational domain to identify different stages of the fire suppression process, as well as to evaluate the suppression performance. The velocity field was analyzed to examine the penetration effect of suppression systems. Relative humidity and oxygen concentration data obtained by gas analyzers were also studied to further understand the droplet/fire interaction behavior. It was found that latent cooling, volumetric displacement, and dilution of oxygen and fuel were the main suppression mechanisms for water mist systems, as smaller droplets evaporate more efficiently compared to larger ones. On the other hand, for sprinklers, heat extraction by water droplets from the fire was found to be the main suppression mechanism, and the evaporation effect is not as significant as in water mist systems. According to in-depth parametric studies of water droplet sizes, recommendations for the optimal running conditions have been provided for both systems.

Abstract: After the implementation of a biofuel target in 2017, China, the second largest consumer of oil in the world, accelerated the development of lignocellulosic biomass technology to produce ethanol and minimized food security risks commonly associated with first generation biofuel production. In this study, Life Cycle Assessment (LCA) is used to investigate three new lignocellulosic biomass refinery systems based on corncob which co-produce ethanol with chemicals and energy. The bioethanol is used in E10 and E85 biofuel mixes and these are compared with a fossil gasoline reference system. Using 1 km distance driven by a compact size flexible fuel passenger vehicle as the functional unit and a exergy allocation approach to the raw material inputs and to the co-products in the simulated multifunctional biorefinery processes, the results indicate that regardless of the configuration of the ethanol-biorefinery, ethanol-blended fuels performed better than gasoline in terms of fossil fuels depletion (E10 6% lower; E85 64–70% lower), global warming potential (E10 1–10% lower; E85 5–113% lower) and human toxicity potential (E10 6–7% lower; E85 72–75% lower), but worst in terms of ozone layer depletion (E10 4.5–6.8 times higher; E85 51.9–78.2 times higher), acidification (E10 30–50% higher; E85 3.3–5.5 times higher) and eutrophication potential (E10 5.2–7.0 times higher; E85 42.4–64.0 times higher) than gasoline.

Abstract In order to achieve a perfect bottom-up electroplated Cu filling with a minimal surface thickness, 2-mercaptopyridine (2-MP) was investigated as a new leveler for replacing Janus Green B (JGB) for bottom-up copper filling. Electrochemical impedence results indicate that 2-MP has a stronger suppression for Cu deposition than JGB. With the addition of 2-MP, the filling capability of the electroplating solution is improved significantly with the Cu thickness on surface decreasing from ∼16 μm to ∼10 μm. The interaction mechanisms of 2-MP, bis(3-sulfopropyl) disulfide (SPS), Cl − and tri-block copolymer of PEG and PPG with ethylene oxide terminal blocks (EPE) in the plating solution are studied by galvanostatic measurements (GMs). The acceleration effect of SPS and the inhibition effect of 2-MP on copper deposition occur in the presence of EPE, and the convection-dependent adsorption (CDA) behavior of additives usually occurs with the injection of four additives at optional concentrations. Further, it was found that when 1.0 ppm 2-MP, 1.0 ppm SPS and 200 ppm EPE were injected into the basic electrolyte, the potential difference ( Δ h) value of the electrolyte became positive, and the bottom-up electroplated copper filling was obtained in the electrolyte in absence of Cl − . The interaction mechanisms of three additives for bottom-up filling have been investigated by GMs.

This paper reports results of further investigation of the so-called direct torque control (DTC) technique to an interior permanent magnet (1PM) synchronous motor drive. This torque control technique for IPM motors requires no dq-axes current controllers and coordinate transformnation networks. A completely sensorless 1PM motor drive with DTC, which uses a new speed estimator from the stator flux linkage vector and the torque angle, is presented. It is shown that including the torque angle in the estimation process results in a far more accurate transient speed estimator than what is reported in the existing literature.

The interface between the head of the window and the wall represents one of the largest thermal bridges of a building and one of the areas with the highest risk of surface condensation and mould growth. This study is concerned with the reliability and accuracy of assessing this thermal bridge heat loss and surface temperature at the junction of a window with a specific steel lintel where the window frame itself is excluded from the thermal model. Four cases were modelled, covering the evolution of the construction details of this junction, following changes in British legislation in regards to U-values. They were assessed with HEAT2D software under the standard (simplified) method and a more detailed approach. The outputs revealed that replacing the window frame with an adiabatic surface during the modeling process (as per standard) underestimates the risks of mould growth or surface condensation (as per PartL1A 2010), especially if the window has a high U-value.

Abstract Metallization based on electroless metal plating of nickel and copper is a simple, cost-effective process used in the fabrication of Buried Contact silicon solar cells. Whereas the electroless Ni–Cu metallization scheme works well for metal deposition on early Buried Contact solar cells, in which deposition was required only on phosphorus diffused contact regions, more care is required for advanced Buried Contact solar cell designs that require simultaneous deposition on to both phosphorus and boron diffused contact regions. In this paper, we examine two key issues related to the metallization in these solar cells. Firstly we demonstrate an improved buffered hydrofluoric acid etch process for simultaneous removal of borosilicate and borophosphosilicate glasses from the contact regions prior to electroless deposition of nickel with good etch selectivity against silicon dioxide masking films. Secondly, we demonstrate an improved process for nucleation of the nickel layer on both phosphorus and boron diffused contact areas based on immersion palladium chloride activation of the plating surfaces. N-type double-sided buried contact solar cells metallized by processing introduced in this study show improvement on absolute efficiency of more than 3%.