다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Foreword 1. Prosperity Lost 2. The Age of Irresponsibility 3. Redefining Prosperity 4. The Dilemma of Growth 5. The Myth of Decoupling 6. The 'Iron Cage' of Consumerism 7. Keynesianism and the 'Green New Deal' 8. Ecological Macro-Economics 9. Flourishing - within Limits 10. Governance for Prosperity 11. The Transition to a Sustainable Economy 12. A Lasting Prosperity Appendices References Endnotes

Prosperity without growth : economics for a finite planet

Biodiesel is produced by the transesterification of oil triglycerides with methanol or ethanol, in the presence of a homogeneous or heterogeneous catalyst. This study aims to report the results of the transesterification of sunflower oil with methanol to produce biodiesel using CaO nanoparticles supported on NaX zeolite as catalyst. The effect of the CaO nanoparticles concentration on the NaX zeolite surface was studied in the range of 5−25 wt %. The transesterification reaction was carried out at reflux temperature of methanol, atmospheric pressure, a reaction time of 6 h, and with a 6:1 molar ratio of methanol to sunflower oil. Catalyst characterization was carried out by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. It was concluded that methyl esters content is highly influenced by basicity and that the best catalyst was the one holding 16 wt % CaO nanoparticles. The produced biodiesel was 93.5% methyl esters and was found to fulfill the specifications of Europ...

Preparation and Characterization of CaO Nanoparticles/NaX Zeolite Catalysts for the Transesterification of Sunflower Oil

The world is confronted with the twin crises of fossil fuel depletion and environmental degradation. The indiscriminate extraction and consumption of fossil fuels have led to a reduction in petroleum reserves. Petroleum based fuels are obtained from limited reserves. These finite reserves are highly concentrated in certain region of the world. Therefore, those countries not having these resources are facing a foreign exchange crisis, mainly due to the import of crude petroleum oil. Hence it is necessary to look for alternative fuels, which can be produced from materials available within the country. Although vegetative oils can be fuel for diesel engines, but their high viscosities, low volatilities and poor cold flow properties have led to the investigation of its various derivatives. Among the different possible sources, fatty acid methyl esters, known as Biodiesel fuel derived from triglycerides (vegetable oil and animal fates) by transesterification with methanol, present the promising alternative substitute to diesel fuels and have received the most attention now a day. The main advantages of using Biodiesel are its renewability, better quality exhaust gas emission, its biodegradability and the organic carbon present in it is photosynthetic in origin. It does not contribute to a rise in the level of carbon dioxide in the atmosphere and consequently to the green house effect. This paper reviews the source of production and characterization of vegetable oils and their methyl ester as the substitute of the petroleum fuel and future possibilities of Biodiesel production.

Biodiesel production through the use of different sources and characterization of oils and their esters as the substitute of diesel: A review

Heat transfer enhancement by oscillatory baffled flows

Localized electron energy loss spectroscopy (EELS) studies in the bandgap energy regime were conducted in the GaN/3C-SiC and GaAlInP/GaAs materials systems. Requirements on experimental conditions and data analysis using the VG601UX and the possible interferences arising from instrumental factors and Cerenkov radiation losses are addressed. The bandgap of GaAs can be determined after subtraction of the zero loss peak. This procedure is, however, proned to introduce inaccuracies: GaAlInP shows deviations from the expected bandgap value of 0.5 eV. Materials not requiring subtraction of the zero loss peak fare better: the bandgap values of 3.3 and 3.1 eV obtained for GaN tie in with those obtained from Photoluminescence spectra for hexagonal and cubic GaN. Variations in the midgap states density vary with the location in the film and can be related to the amount of microstructural defects. 

Adam Harvey

Papers

Heat transfer enhancement by oscillatory baffled flows

Electron Energy Loss Spectroscopy in the 2–5 eV Regime

Environment-Friendly Epoxidation of Limonene Using Tungsten-Based Polyoxometalate Catalyst

Flow field and heat transfer characteristics in oscillatory flow reactors with helical coil inserts

Electron energy loss spectroscopy of extended defects