Very fast H2 production from the methanolysis of NaBH4 by metal‐free poly(ethylene imine) microgel catalysts

The polyethyleneimine (PEI) microgels prepared via microemulsion polymerization are protonated by hydrochloric acid treatment (p‐PEI) and quaternized (q‐PEI) via modification reaction with methyl iodide and with bromo alkanes of different alkyl chain lengths such as 1‐bromoethane, 1‐bromobutane, 1‐bromohexane, and 1‐bromooctane. The bare p‐PEI and q‐PEI microgels are used as catalysts directly without any metal nanoparticles for the methanolysis reaction of sodium borohydride (NaBH₄). Various parameters such as the protonation/quaternization reaction on PEI microgels, the amount of catalyst, the amount of NaBH₄, and temperature are investigated for their effects on the hydrogen (H₂) production rate. The reaction of self‐methanolysis of NaBH₄ finishes in about 32.5 min, whereas the bare PEI microgel as catalyst finishes the methanolysis of NaBH₄ in 22 min. Surprisingly, it is found that when the protonated PEI microgels are used as catalyst, the same methanolysis of NaBH₄ is finished in 1.5 min. The highest H₂ generation rate value is observed for protonated PEI microgels (10 mg) with 8013 mL of H₂/(g of catalyst.min) for the methanolysis of NaBH₄. Moreover, activation parameters are also calculated with activation energy value of 23.7 kJ/mol, enthalpy 20.9 kJ/mol, and entropy ?158 J/K.mol. Copyright © 2016 John Wiley & Sons, Ltd.     

博弈结构、生产方式与双方道德风险组织激励

基于委托代理理论给出了双方道德风险组织激励问题的基本分析框架,建立合作与非合作博弈结构下双方道德风险组织激励问题的规划模型。以分析框架与规划模型为基础,引入线性生产与协作生产两种具体的生产方式,全面对比分析了不同博弈结构、不同生产方式下双方道德风险组织激励的均衡努力、最优契约和效用水平,揭示了不同博弈结构、不同生产方式下双方道德风险组织激励问题的特点与规律。     

施工质量控制要素及PDCA循环应用

施工生产要素是施工质量形成的物质基础,关系到施工质量的优劣,所以在施工过程中应加强对各生产要素的管理,并运用动态控制的原理来保证在实践环节的运用有效性。文章指出哪些是控制的重点,并且对PDCA模式的运用进行深入浅出的描述,旨在为施工质量控制提供理论支持。     

A p-n heterojunction NiS-sensitized TiO2 photocatalytic system for efficient photoreduction of carbon dioxide to methane

Nanoparticles of the p-type semiconductor nickel sulfide are grown on a highly aligned n-type TiO₂ film. Using XRD, XPS, EDS, UV–Vis diffuse reflectance spectroscopy, photoluminescence, photocurrent density, and CO₂-TPD, the physicochemical characteristics of the p-n heterojunction NiS-sensitized TiO₂ films are investigated. The highest photocurrent is obtained for the optimized 0.10 M NiS-sensitized TiO₂ film, which resulted in eventually decreasing the electron-hole recombination during CO₂ photoreduction. The NiS-sensitized TiO₂ film exhibits superior photocatalytic behavior compared to that of a pure TiO₂ film. A model for investigating the catalytic activity of the NiS-sensitized TiO₂ film for CO₂ photoreduction is proposed.     

Production planning in automotive powertrain plants: a case study

Based on a real case study from the automotive industry, this paper deals with production planning in powertrain plants. We present an overview of the production planning process and propose a mixed integer linear programme to determine the production quantities of each product over a planning horizon of several days. Then, using real data of an engine assembly line, we simulate the performance obtained through the proposed model within a rolling horizon planning process. We perform multiple tests in order to evaluate the impact of two parameters involved in this process: planning frequency and frozen horizon length. Furthermore, in order to illustrate the value of improving coordination between engine plants and their customers, we evaluate the impact of the quality of demand information (orders and forecasts). We analyse the simulation results and provide insights and recommendations in order to achieve a good trade-off between service level, inventory, and planning stability.     

Effect of Flaxseed Meals and Extracts on Lipid Stability in a Stored Meat Product

Flaxseeds have been recently in focus due to the antioxidant capacity of some of their compounds. However, there is a lack of easily accessible information concerning their activity against lipid oxidation in food systems. Therefore, the aim of the study was to determine the effect of defatted meals (DFM) and the aqueous extracts (AFE) obtained from brown and golden flaxseeds on lipid oxidation in pork meatballs. Fatty acid composition, peroxide value (PV), thiobarbituric acid reactive substances (TBARS) and cholesterol content were monitored during 6 months of freezer storage. Cholesterol oxidation products were identified and quantified. Both DFM and AFE limited fatty acid and cholesterol oxidation during meatball storage. Their antioxidant effect depended on flax variety (brown or golden) and preparation type (DFM or AFE). Lower level of PV and TBARS, compared with the ones with AFE, were noted in meatballs with DFM. Both DFM and AFE, from the brown seed variety, protect the lipids against oxidation to a higher extent. During the storage, a cholesterol degradation was observed. AFE (particularly from the brown variety) limited changes in cholesterol content. Moreover, they stabilized fatty acid composition of stored meatballs. However, DFM efficiently inhibited cholesterol oxidation.     

Long-term water balance and sustainable production of Miscanthus energy crops in the Loess Plateau of China

Sustainable production of second-generation energy crops on marginal land holds a great potential for renewable energy development. Because a vast area of marginal land is located in the arid and semiarid regions of the world, water shortage is the most serious environmental limitation. In this study, we developed a water balance model to address the question of whether Miscanthus energy crops can be sustainably produced in the Loess Plateau of China, a region of more than 60 million hectares particularly abundant in semiarid marginal land. The simulation of 20-year soil water content in bare soil, the winter wheat field, and the Miscanthus field across the Loess Plateau suggested that the long-term production of Miscanthus would not cause water depletion in deep soil. This finding addressed a serious concern that growing high-biomass plants in the Loess Plateau might lead to deep-soil water depletion, which was suggested to be the cause of previous failure of afforestation. Planting Miscanthus was effective in reducing surface runoff and consequently preventing water and soil loss in this heavily eroded region. The model and analyses illustrated where in the Loess Plateau this perennial energy crop could be produced with stable and sufficient yield.     

Integration of wind turbine with heliostat based CSP/CPVT system for hydrogen production and polygeneration: A thermodynamic comparison

In this study, two wind-solar-based polygeneration systems namely CES-1 and CES-2 are developed, modeled, and analyzed thermodynamically. CES-1 hybridizes a heliostat based CSP system with wind turbines while CES-2 integrates heliostat-based CPVT with wind turbines. This study aims to compare the production and thermodynamics performance of two heliostat based concentrated solar power technologies when hybridized with wind turbines. The systems have been modeled to produce, freshwater, hot water, electricity, hydrogen, and cooling with different cycles/subsystems. While the overall objective of the study is to model two polygeneration systems with improved energy and exergy performances, the performances of two solar technologies are compared. The wind turbine system integrated with the comprehensive energy systems will produce 1.14 MW of electricity and it has 72.2% energy and exergy efficiency. Also, based on the same solar energy input, the performance of the heliostat integrated CPVT system (CES-2) is found to be better than that of the CSP based system (CES-1). The polygeneration thermal and exergy efficiencies for the two systems respectively are 48.08% and 31.67% for CES-1; 59.7% and 43.91% for CES-2. Also, the electric power produced by CES-2 is 280 kW higher in comparison to CES-1.     

Effect of titania synthesis conditions on the catalytic performance of mesoporous Ni/TiO2 catalysts for carbon dioxide reforming of methane

The catalytic performance of 5 wt% Ni/TiO₂ catalysts with different physicochemical properties was studied for the CO₂ reforming of methane reaction. The TiO₂ supports were prepared by the evaporation-induced self-assembly method using three different titania metal precursors. The catalysts were characterized by XRD, BET, TGA, and TEM techniques. The results showed that the phase composition of TiO₂ support plays a crucial role in catalyst performance. Furthermore, the variation of synthesis conditions significantly affects the physicochemical properties of TiO₂ support. NH₃-treatment helped maintain the higher surface area by retaining a significant fraction of the amorphous content of titania support. Catalysts deactivation was caused by the phase transformation of TiO₂ from anatase to rutile and the sintering of Ni metal. Phase transformation into rutile was more significant, with the catalysts possessing a higher content of amorphous TiO₂. Ni/TiO₂ catalyst prepared using the titanium ethoxide precursor performed better in the dry reforming reaction. Anatase titania offers strong metal-support interaction, whereas weak metal-support interaction was observed in the amorphous and rutile phase.