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In this paper we seek to understand the impact of expanded use of soybean oil biodiesel to address biofuel mandates on global vegetable oil markets, and in particular on the demand for palm oil. An open-economy equilibrium model is derived to investigate the market effects of biodiesel expansion on related energy and vegetable oil markets. The model is calibrated to represent the recent benchmark data in calendar year 2011. The simulation estimates suggest that the expanded use of soy oil for biodiesel in the US will have considerable impacts on world vegetable oils markets. The majority of the vegetable oil replacement is likely to occur through substitution of palm oil under a wide range of plausible elasticity values on the demand for vegetable oil and the demand substitution between soy oils and palm oils.

Abstract Sustainable production of biofuels has provided an attractive alternative to fossil fuels, which has relieved the concern regarding energy supply and global climate change. Currently, interest in metabolic engineering of yeasts as microbial cell factories for biofuel production, which varies from short-chain ethanol to long-chain fatty acid-derived molecules, is growing. The commercial production of new energy-dense biofuels using yeasts and new synthetic biology tools is now possible due to recent developments in metabolic engineering. Here, it is attempted to comprehensively and critically review the latest advances in metabolism-targeted strategies and the production of different types of biofuels using yeasts. Furthermore, the key challenges and perspectives have been discussed for improving yeast biorefineries for the production of biofuels, such as host compatibility of heterologous genes, substrate extension for alternative feedstocks, better tools for reprogramming cell metabolism, host robustness for tolerating or alleviating toxicity induced by end products, and new design principles with predictable behaviors for the constructed biological systems.

Abstract In recent years, solar steam generation has attracted many attentions due to its potential applications in desalination, etc. In the present work, a bi-layer solar steam generation system is prepared by daubing carbon particles on the sintered sawdust film, which possesses an advantage of adjustable porosities compared to widely used wood. Then, the influence of the porosity on the evaporation performance is explored. The experimental result indicates that: the porosity could significantly affect the water transportation in the film, and the water diffusivity increases almost linearly with the increase of the porosity. The evaporation efficiency increases with the increasing porosity, until the porosity reaches about 0.52 then decrease slowly. The positive effect of the increased water diffusivity and the negative effect of the increased thermal conductivity of the bottom film layer determine that the porosity of 0.52 is optimal for improving the evaporation efficiency. Under a solar light power of 1 kW·m−2, the optimal porosity gives an evaporation efficiency of 77.64%, which is comparable to the best performance of bi-layer systems reported in previous works. The conduction of heat through the bottom layer to the bulk water and the convection heat loss on the top surface contribute 83% to the total heat losses in the system, suggesting that the energy losses of these two modes should be further reduced in the future applications. Considering the accessible materials, easy preparation, low cost and high efficiency, we conclude that the 0.52-porosity system is suitable for being used as an efficient solar steam generation device.

Due to the high similarity of photovoltaic images, the difficulty of registering photovoltaic images increases while the accuracy requirement for registering images is high. This article proposed a guided spatial consensus registration algorithm based on local structural similarity constraint. First, local similarity structural constraints are established based on the characteristics of the neighborhood structure among adjacent matching feature points. Second, outliers are eliminated based on the proposed similarity structural constraints to obtain a high-precision matching feature set among a strictly constrained initial matching feature set. Third, the corresponding geometric parameter of the high-precision matching feature set is used as guided information for the selection of the final inlier set from a weakly constrained initial matching feature set. Finally, the proposed method is validated by photovoltaic images with brightness and geometric differences. The experimental results demonstrate the robustness and efficiency of the proposed algorithm in the application of photovoltaic images.

Abstract Injection molding machines consume a large amount of energy in the production process, during which the power units are the most significant factor. In order to understand the energy consumption of injection molding machines driven by different types of electro-hydraulic power units, the energy efficiencies of the asynchronous motor, the servo motor and the hydraulic pump under different working conditions are firstly analyzed. Then, the power consumptions of five different types of electro-hydraulic power units during different injection molding stages are compared and analyzed. Finally, the energy consumptions of the injection molding machine during a working cycle driven by these five power units are tested and analyzed respectively. The results indicate that the power unit using a fixed displacement pump driven by an asynchronous motor has the largest energy consumption. Compared to this power unit, the energy consumptions of other units, i.e. a fixed displacement pump driven by a speed variable asynchronous motor, a variable displacement pump driven by an asynchronous motor or driven by a speed variable asynchronous motor, and a fixed displacement pump driven by a servo motor, can be reduced by 47%, 69%, 78% and 87% respectively.

Abstract Lignin is considered as a renewable and sustainable resource for producing value-added aromatic chemicals and functional carbon materials. Herein, we develop a one-step catalyst-free depolymerization strategy to convert lignin into aryl monomers and carbon nanospheres simultaneously. Importantly, microwave-assisted depolymerization (MAD) in conjunction with dichloromethane (CH2Cl2) vapors is developed. The total mass yield of guaiacols reached the highest amount of 225.1 mg/g at 600 °C, and the highest yields of phenols (49.0 mg/g) and aromatic hydrocarbons (155.1 mg/g) were obtained at 700 °C. Hydrogen radicals and hydrogen chloride (HCl) are in-situ formed from CH2Cl2, significantly decreasing the activation barrier and reforming pyrolysis vapors to promote the formation of aryl monomers. Interestingly, uniform carbon nanospheres with an average size of 140 nm were produced as co-products at 700 °C. The microwave “hot-spots”, allied with the continuous surface erosion and the decrease in surface energy of lignin-derived carbon precursors by CH2Cl2 vapor, can be considered the driving force for the ultimate formation of carbon nanospheres. The CH2Cl2/MAD system produces aryl monomers (26.8 wt% yield) and carbon nanospheres (36.6 wt% yield) at 700 °C. We provide a facile, intriguing and scalable approach to convert lignin to valuable aryl monomers and sustainable carbon materials that can be applied in the chemistry, energy and environmental fields.

AbstractReview: 50 refs.

Access to reliable and affordable energy is vital for sustainable development. In the off-grid areas of developing countries, decentralized energy solutions have received increasing attention due to their contributions to reducing poverty. However, most of the rural population in many developing countries still has little or no access to modern energy technologies. This paper assesses the factors that determine the successes and failures of decentralized energy solutions based on local harmonized case studies from heterogeneous contexts from Asia, sub-Saharan Africa, and South America. The case studies were analyzed through the coupled lenses of energy transition and the Water–Energy–Food Security (WEF) Nexus. The findings indicate that access to modern decentralized energy solutions has not resulted in complete energy transitions due to various tradeoffs with the other domains of the WEF Nexus. On the other hand, the case studies point at the potential for improvements in food security, incomes, health, the empowerment of women, and resource conservation when synergies between decentralized energy solutions and other components of the WEF Nexus are present.

Abstract Uncertainties of cell temperature and aging are two challenges for the power management of battery-integrated systems. To evaluate the maximum power capability of batteries with uncertain degree of degradation and internal temperature, a temperature-compensated battery model is first established as a base model in this paper. Then the linear migration with particle filtering is employed to adjust the developed base model so that the migrated model can be adaptive to the uncertainties of aging and internal temperature. Moreover, a numerical seeking method is proposed for state of power (SoP) calculation to avoid direct handling of the complex, highly nonlinear battery model. After that, the multiple constraints such as current, state of charge (SoC), and voltage limitations are considered for SoP estimation. Experimental results show that for the cases of capacity degradation up to 15%, temperature variation up to 40 °C, and the root-mean-square error (RMSE) of the voltage measurement noise up to 50 mV, the RMSE of the voltage tracking for SoP calculation can still be limited to 8.4 mV, and the RMSE of the SoC estimation is better than 1.64%. In addition, the computational efficiency of the proposed seeking algorithm is stable with particle filters using different configurations.