• Energy Research
• US close
• IT close
• GB close
• RU close
• English close

In the analysis of unprotected loss-of-flow and overpower transients of liquid metal fast breeder reactors, the modeling of heat transfer from molten fuel, ejected into the coolant channel after cladding rupture, to liquid sodium is an important part of fuel-coolant interaction (FCI). Some of the ejected molten fuel fragments into small particles and gets dispersed in the coolant. In the PLUT02 code model and other modeling efforts of FCI it is assumed that the fuel particle to liquid sodium heat transfer is limited only by the thermal conduction resistance of the fuel because the thermal conductivity of liquid sodium is about 30 times higher than that of mixed oxide. The fuel particle (assumed to be a sphere) surface temperature, under this assumption, equals the coolant temperature. The purpose of the present analysis is to obtain the value of meter C/sub 1/ (for V/sub l/ = 1) by solving the linear transient heat conduction equation a constant parameter in the equation for evaluating the fuel-coolant heat transfer coefficient.

Chiefly tables. ; Second in a series. ; Mode of access: Internet.

Energy efficiency is among the cheapest, cleanest, and most widely available of energy resources. Improved energy efficiency provides opportunities to sustainably expand energy services and support development and economic growth, contributing to higher living standards, as well as reducing greenhouse gas emissions. In developing countries, where demand for energy is growing rapidly, the potential for energy efficiency improvements is significant, particularly in the residential sector. The purpose of this guide is to raise awareness of behavioral approaches to achieving development outcomes, demonstrate the role that behavioral sciences can play in promoting energy efficiency, and provide guidance on how to integrate behavior change approaches into projects.

Establishing a sustainable future requires the replacement of petroleum as the primary carbon source for modern industry. Biomass derived species offer a promising alternative to petroleum derived species for fuel and chemical production. However, such species are often low molecular weight and heavily oxygenated, and require reductive upgrading or coupling to form more valuable species. Electrochemistry offers a promising technology for biomass upgrading. Easily utilizing renewable energy sources, such as wind and solar power, electrochemical reduction uses an applied electrical potential to drive the reduction of biomass species. This technique applies to a wide range of functional groups, including aromatic rings, C=C bonds and carbonyls. Despite these advantages, electrochemical biomass upgrading largely remains unviable due to poor catalysts and a lack of mechanistic understanding. This work seeks to advance the mechanistic understanding of electrochemical biomass upgrading by investigating the electrochemical reduction of carbonyl species. ☐ The first chapter investigates benzaldehyde reduction on four different metals: Cu, Au, Pt and Pd. Reactivity tests show a large difference in reduction selectivity between metals, with Cu showing benzaldehyde coupling ability, while the other metals do not. In situ infrared spectroscopy experiments suggest this difference in coupling ability results from the relative ability of the metal surface to stabilize the ketyl radical reaction intermediate. Spectroscopic features related to the ketyl radical appear on Au and Cu surfaces, but not on Pt or Pd. The appearance of radicals on both Au and Cu suggests the difference in Cu and Au coupling ability results from a lower radical concentration on Au, likely due to lower radical stability. On Pt and Pd, CO appears under reduction conditions, suggesting the general instability of benzaldehyde adsorbates limits surface coverage and coupling ability. Combined, the spectroscopic and reactivity evidence suggest ketyl radical stability acts as a key descriptor of benzaldehyde coupling ability. ☐ Subsequently, the second chapter extends the analysis to the reductive coupling of benzaldehyde and furfural on Cu and Pb electrodes. Under simultaneous reduction, reactivity tests show both the self-coupling and cross-coupling of the aldehyde species on the two metal surfaces, but with different selectivities. Cu shows greater selectivity for cross-coupling, whereas Pb favors furfural coupling. Comparison with a stochastic model suggests both metals deviate from stochastic coupling control, with greater deviation on Pb, likely due to a larger difference in aldehyde binding energies. Cyclic voltammetry and in situ spectroscopy further support stronger benzaldehyde adsorption compared to furfural on both metals, with a larger difference in binding energy for Pb. Combined, the reactivity, cyclic voltammetry and spectroscopy experiments suggest that the cross-coupling of two aldehydes follows a two reactant Sabatier rule, with optimum cross-coupling for electrodes with similar reactant binding energies. ☐ Finally, the third chapter investigates the effect of structure on reduction activity for aliphatic ketone reduction on Pb and Au electrodes. Specifically, reduction kinetics are investigated for acetone, 2-butanone, 2-pentanone, 2-hexanone, cyclopentanone and cyclohexanone. Reactivity tests show only an alcohol product, with reduction activity decreasing with size for the linear ketones. Cyclic species show higher activity than the corresponding linear species, with activity increasing with ketone size. Similar Tafel slopes suggest a common reduction mechanism for all ketones on both metals. A change in Tafel slope with potential suggests a change in the ketone reaction network. Comparison with a simple model suggests this change likely results from increased hydrogen competition at lower potentials. Rate order and pH dependent measurements further support this explanation. Temperature dependent measurements suggest that rate decreases with ketone size result from a smaller pre-exponential factor. Comparison with a kinetic model suggests the decrease in pre-exponential factor results from weaker orbital overlap for larger ketones, with hydraulic radius offering a good descriptor for ketone size. Cyclohexanone proves the exception, likely due to a different binding orientation or higher binding strength. Activation energy measurements suggest similar intrinsic activation energies for all ketone species, with variation in observed activation energy resulting from different adsorption energies.

Issued September 26, 1919. ; Mode of access: Internet.

"July 31, 1968." ; Includes bibliographical references (p. 45-46) ; Sponsored by the Air Force Office of Scientific Research, Office of Aerospace Research, United States Airforce, under AFOSR Contracts ; Mode of access: Internet.

This work has been developed under the AGROinLOG Project, “Demonstration of innovative integrated biomass logistics centres for the Agro-industry sector in Europe”. An Integrated Biomass Logistics Center (IBLC), is based on the introduction of new production chains into existing agro-industries by using new biomass feedstock. The AGROinLOG Project has dedicated great attention to investigate the potential of cereal chaff as a valuable resource.Chaff is the fine fraction of the thrashing residues, not usually collected. Chaff is made up of glumes, seed husks, rachis and the tinner part of the cereal stems, whole and cracked kernels, as well as weed seeds.Currently there are several mechanical solutions available on the market for chaff recovery, and others are still at prototype stage, but theyare not so common and very often unknown to the farmers.So far, the literature reportsfew cases of chaff collection with the specific purpose of weed seeds removal, but it still lacks specificexperiments on these machinesintentionally used for biomass collection.For this reason, during the Project AGROinLOG a series of large field tests were performed using an independent scientific approach with different kind of chaff harvesting technologiesin France, Sweden and Italy from 2017 to 2019.The present study collects the results of these activities with the aim to fill that gap and provide deeper understanding in the possibility to enhance the current cereal harvesting method, in order to improve the quantity of biomass collected by including the chaff. Proceedings of the 29th European Biomass Conference and Exhibition, 26-29 April 2021, Online, pp. 62-68

The objective of this paper is to analyze and quantify the inertia and frequency responses of wind power plants with different wind turbine technologies (particularly those of fixed speed, variable slip with rotor-resistance controls, and variable speed with vector controls).

The Country Opinion Survey in Swaziland assists the World Bank Group (WBG) in gaining a better understanding of how stakeholders in Swaziland perceive the WBG. It provides the WBG with systematic feedback from national and local governments, multilateral/bilateral agencies, media, academia, the private sector, and civil society in Swaziland on 1) their views regarding the general environment in Swaziland; 2) their overall attitudes toward the WBG in Swaziland; 3) overall impressions of the WBG’s effectiveness and results, knowledge work and activities, and communication and information sharing in Swaziland; and 4) their perceptions of the WBG’s future role in Swaziland.

Green ammonia is gaining momentum as a globally significant technology for deep decarbonisation. In this thesis, several models are developed across chemical, techno-economic, and energy system modelling disciplines to explore the future role of green ammonia. First, standalone models of production (i.e., power-to-ammonia) and re-electrification (i.e., ammonia-to-power) are developed and compared to competing technologies. Second, these models are integrated into a planning and dispatch energy system model (ESM) of India to 2050. The ESM has several novel additions including the sector coupling of hydrogen and ammonia, multiple years of granular weather data, and learning-curve-based technology cost forecasts. India is chosen as an ideal case study given its globally unmatched demand growth in all three relevant sectors: electricity, green hydrogen, and green ammonia. The projected electricity demands for green hydrogen and ammonia production account for 25% of the total Indian electricity demand in 2050, underscoring the transformational potential that green hydrogen and ammonia sector coupling can have on the Indian energy system. The results of the state-of-the-art ESM highlight synergistic effects of hydrogen and ammonia sector coupling with the power system. The least-cost system employs seasonal green ammonia production paired with up to 40 million tonnes (i.e., 200 TWh) of ammonia storage, as well as some re-electrification via gas turbines. Sector coupling reduces system curtailment, addresses challenges of long-duration storage, and improves system resilience to interannual weather variations. While India is a crucial case study from a global decarbonisation perspective, the methodology and findings are generally applicable, and it is the aim of this work to motivate and accelerate the wider research community into considering the potential impacts of green ammonia sector coupling on electricity grid design. Finally, this work highlights strategic technology development direction for ammonia producers and gas turbine manufacturers, as well as implications for policymakers.