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Modern wave power generation plants are capable to work in variable speed operations. These wave power generation plants are provided with adjustable speed generators, like the double feed induction generator. One of the main advantages of adjustable speed generators is that they improve the system efficiency compared to fixed speed generators, because turbine speed can be adjusted as a function of the flow coefficient to maximize the output power. However these systems require a suitable speed controller in order to track the optimal turbine reference speed. In this work, a sliding mode control for variable speed wave power generation plants is proposed. The stability analysis of the proposed controller is provided under disturbances and parameter uncertainties by using the Lyapunov stability theory. Finally simulated results show, on the one hand that the proposed controller provides high-performance dynamic characteristics, and on the other hand that this scheme is robust with respect to the uncertainties that usually appear in the real systems. [ABSTRACT FROM AUTHOR]

A techno-economic analysis of a natural gas combined cycle (NGCC) integrated with MEA-based CO 2 capture with an advanced configuration is carried out. Sequential supplementary firing in the Heat Recovery Steam Generator (HRSG) is combined with a supercritical combined cycle for the purpose of increasing CO 2 production for Enhanced Oil Recovery (EOR) at a competitive levelised cost of electricity. Supercritical steam conditions with a double reheat in the steam cycle are used to largely improve performance and take full advantage of sequential supplementary firing in the HRSG. Sequential supplementary firing increases the flue gas temperature throughout the Heat Recovery Steam Generator (HRSG) by burning additional fuel at different stages to maximise the use of oxygen available in the flue gas exiting the gas turbine. The positive impact on the post combustion capture plant size and energy requirements for solvent regeneration are attractive for markets with cheap natural gas, and where the emphasis on capital cost reduction is important. This study then investigates the effect of fuel prices and capital costs for this configuration and compares it with a typical combined cycle integrated with MEA-based CO 2 capture. A case study for Mexico is presented, at a range of gas prices where these modifications would be attractive, with a tentative target of $40/tCO 2 . [ABSTRACT FROM AUTHOR]

Objective: The aim of our work was to carry out a randomized clinical trial with two diets, one enriched in fiber (total fiber 30 g and soluble fiber 4 g) to investigate the effect on lipid and glucose levels in healthy subjects. Research design and methods: Fifty-three subjects were prospectively randomized to two groups (see Table 1). Group I received a diet with 10.4 g of fiber given as 1.97 g soluble fiber (pectins, gums and mucilages) and 8.13 g of insoluble fiber (hemicelullose, cellulose and lignins) and Group II received a diet with 30.5 g of fiber of which 4.11 g were soluble fiber and 25.08 g insoluble fiber. Prospective serial assessment of weight and nutritional intake (3 days written food records) were made. These determinations were performed at baseline and at 3 months. All enrolled subjects underwent the following examinations; fasting blood samples were drawn for measurement of total cholesterol, triglyceride concentrations and other lipid fractions, low density lipoprotein (LDL-cholesterol), high density lipoprotein (HDL-cholesterol), glucose, and insulin. Results: Total calorie and fat consumption were lower than recommended in both groups (calories; group I 1633±417 kcal per day versus group II 1707.5±579 kcal per day:ns) and (fats; group I 73.4±22.7 g per day versus group II 72.6±28 g per day:ns), without differences in fatty acid intake profile. Total fiber intake did not reach that recommended in both diets but it was higher in group II (9.06±2.7 g per day versus 25.95±7.12 g per day: P<0.05). Soluble fiber intake did not reach that recommended in both diets but it was higher in group II (1.7±0.58 g per day versus 3.5±0.96 g per day: P<0.05). Body weight did not change in both groups during treatment. During treatment, in group II a significant change was detected from baseline in LDL-cholesterol and fasting glucose levels. LDL-cholesterol decreased by 12.8% (P<0.05) and glucose decreased by 12.3% (P<0.05). No statistical differences were detected among triglycerides, HDL-cholesterol, and insulin levels. Conclusions: Modest increases in soluble fiber intake in healthy subjects improved LDL cholesterol and glucose levels. [Copyright &y& Elsevier]