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Abstract The diffusion coefficients for lithium ions in tungsten oxide and titania-doped tungsten oxide have been measured using the AC impedance spectroscopy technique. Films were prepared using both sol–gel dip coating and DC magnetron sputtering at various substrate temperatures. The diffusion coefficients for sol–gel deposited films post-processed at higher temperatures (400°C) are lower than for lower processing temperatures (300°C). For sputtered films the diffusion coefficients for higher substrate temperatures are similar to those for lower substrate temperatures. While there is a weak dependence of diffusion coefficient on level of charge injection, there is a strong correlation between the optical modulation of the films and the diffusion coefficient, with significantly larger optical modulation for films with larger diffusion coefficients. A possible explanation for this correlation in terms of film microstructure is discussed.

Solar aided power generation (SAPG) is the synergy of solar and fossil plant technology, namely combining the environmental benefits of the former and the scale, efficiency and reliability of the latter. Power plant simulations were performed using weather data for Lephalale, South Africa; home to the Matimba and, currently under construction, Medupi coal-fired power stations. A SAPG plant at Lephalale was compared to a stand-alone concentrating solar power (CSP) in a good solar resource area, namely Upington, South Africa. Parabolic trough collector solar fields of equal size were considered for both configurations. The annual electricity generated from solar thermal at the SAPG plant is more than 25% greater than the stand-alone CSP plant. If the cost of SAPG is taken as 72% of the cost of a stand-alone CSP, SAPG is 1.8 times more cost effective than the stand-alone CSP option.

Based on the characteristics of turbulent combustion in lean-premix combustion chambers, this paper presents a combustion model which solves transport equations for six chemical species. The source terms are calculated by probability weighted integration of 35 elementary reaction rates. The model presented here does not include any adjustable parameters. Therefore, it is universal in its character for conditions of highly turbulent premixed lean to stoichiometric combustion. The model is applicable to fuel compositions including methane, carbon monoxide, and hydrogen. The application is shown for a test case burning methane in lean-premixed mode.

A series of industrial mixed flowing gas tests using real connectors were performed to investigate the effects of electrical power on the life of gold-plated contacts. The connectors were divided into three sets: unmated, unpowered, and powered. Change in contact resistance was used as the measure of contact performance. The results showed that with real contacts, the shielding provided by the housing, when a connector is mated, significantly inhibits corrosion at the interface, even in the harshest environments. As a consequence, levels of corrosion produced at the interface with the unpowered and powered sets were very small. A marginal increase in contact resistance was, however, detected when contacts had been powered to rated current. In order to investigate the phenomena in more detail, more severe atmospheres and less well-shielded connectors were used. These subsequent tests produced increases in corrosion at the contact interface, particularly for the powered sets. The change in resistance of the powered contacts was higher (sometimes greater than five times) than that of the unpowered sets. It is suggested that this result is due to the rise in temperature at the interface of the powered contacts increasing the rate of chemical reaction. Continuous monitoring of resistance during the tests produced resistance changes consistent with the phenomena of self-healing. >

A hybrid drive wind turbine equipped with a speed regulating differential mechanism can generate electricity at the grid frequency by an electrically excited synchronous generator without requiring fully or partially rated converters. This mechanism has extensively been studied in recent years. To enhance the transient operation performance and low-voltage ride-through capacity of the proposed hybrid drive wind turbine, we aim to synthesize an advanced control scheme for the flexible regulation of synchronous generator excitation based on fractional-order sliding mode theory. Moreover, an extended state observer is constructed to cooperate with the designed controller and jointly compensate for parametric uncertainties and external disturbances. A dedicated simulation model of a 1.5 MW hybrid drive wind turbine is established and verified through an experimental platform. The results show satisfactory model performance with the maximum and average speed errors of 1.67% and 1.05%, respectively. Moreover, comparative case studies are carried out considering parametric uncertainties and different wind conditions and grid faults, by which the superiority of the proposed controller for improving system on-grid operation performance is verified.

Waste-printed circuit boards (WPCBs) account for approximately 3–6 wt% of total electronic waste. Due to their content of thermosetting materials and added brominated fire retardants, their recycling and disposal is difficult and not eco-friendly. Pyrolysis as a thermal degradation process may assist in the solution of this problem. In addition, using biomass as an additive can upgrade the bio-oil and fix bromines in the char. In this study, cotton stalk (CS) is chosen as an additive and kinetic of the pyrolysis of three samples namely: PCB, CS, and CS:PCB (50:50) were investigated by the thermogravimetric analyzer (TGA) at heating rates of 5, 10, and 15 K/min. Three non-isothermal methods: FWO, KAS, and Starink were found in good agreement with the TGA data; however, the FWO method was more efficient in the description of the degradation mechanism of solid-state reactions. For CS and CS:PCB (50:50), α was increased from 0.2 to 0.9 with the FWO method, and calculated Eα values were found in the range of 121.43–151.88 and 151.60–105.67 kJ/mol in zone 1, while 197.06–79.22 and 115.90–275.06 kJ/mol in zone 2, respectively. Whereas, for PCB in zone 1, Eα values were found to be in the range of 190.23–93.88 kJ/mol. The possible decomposition mechanism was determined by the Criado method, which was in agreement with the mechanism model for reaction order n = 3. The oil product was also analyzed using Fourier-Transform Infrared Spectroscopy analysis.

Paper discusses the approach that supports the decision-making under need to provide total multi-line electrical energy supply under appointed maximum level. The data available from power meters allows to estimate the boarders of acceptable level for the external power supply and to predict its overshoot. It leads to rapid decision-making and allows to avoid the penalties on behalf of the power distribution utilities. Data approximation in the form of ellipsoid gives clear graphics and concise analytical description of the desired boarder. Introduced in the paper algorithm involves logarithmic functional transformation of the target criterion that allows to convert the meter data approximation via maximum volume ellipsoid problem to the convex nonlinear mathematical programming.

Paying close attention to the environmental risks associated with traditional forms of energy, particularly the serious issue of global warming caused by the release and concentration of greenhouse gases, has become a paramount concern. This growing awareness has prompted governments worldwide to prioritize the benefits of alternative energy sources and develop comprehensive plans accordingly. Moreover, it is crucial to thoroughly consider and explore existing potentials in our quest for sustainable energy solutions. One such potential lies in the energy loss experienced due to gas pressure reduction in urban gas reduction stations. Furthermore, as we increase the amount of natural gas preheating, we observe a corresponding rise in the temperature within the expansion turbine, ultimately resulting in a significant boost in power generation. In this paper, we delve into the exciting possibility of harnessing electricity generation by utilizing a turbo expander within a municipal gas pressure reduction station. To maximize the work generation capacity, we propose preheating the gas input to the turbo expander using geothermal energy. Our study reveals that the turbo expander exhibits optimal performance, boasting an impressive isentropic efficiency of 92.3%, when the inlet temperature is maintained at 84 °C and the amount of preheating reaches 192.3 kJ/kg.

In the present work, the titanium oxide platinum (TiO2/Pt) composite particles were deposited on the Si and glass substrates at (400)°C using pulsed laser deposition technique to ablation of TiO2 target at constant laser energy 800 mJ, a double frequency Q-switching Nd: YAG laser beam ( λ= 532 nm, repetition rate 6Hz and the pulsed duration 10ns). Ultraviolet visible (UV-Vis) spectroscopy, X-ray diffraction (XRD),X-ray fluorescence (XRF), Atomic force microscopy (AFM),Scanning Electron Microscopy (SEM), electrical conductivity (σdc), Hall coefficient (RH) ,(I-V) and (C-V) were used to characterize the morphology and electrical of the films. The results showed that the transparency of film reached to about (80%) with optical band gap (3.64) and (3.76) eV for Pure TiO2 and 5% Pt:TiO2 respectively. The structural and composition of the obtained films at level 5% of platinum doping into TiO2 have been determined. The results indicated that the prepared films (Pt doped TiO2) were nanostructure and uniform with diameters less than 20 nm.