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[en] The efficiency of materials developed for solar energy and technological applications depends on the interplay between molecular architecture and light-induced electronic energy redistribution. The spatial localization of electronic excitations is very sensitive to molecular distortions. Vibrational nuclear motions can couple to electronic dynamics driving changes in localization. The electronic energy transfer among multiple chromophores arises from several distinct mechanisms that can give rise to experimentally measured signals. Atomistic simulations of coupled electron-vibrational dynamics can help uncover the nuclear motions directing energy flow. Through careful analysis of excited state wave function evolution and a useful fragmenting of multichromophore systems, through-bond transport and exciton hopping (through-space) mechanisms can be distinguished. Such insights are crucial in the interpretation of fluorescence anisotropy measurements and can aid materials design. Finally, this Perspective highlights the interconnected vibrational and electronic motions at the foundation of nonadiabatic dynamics where nuclear motions, including torsional rotations and bond vibrations, drive electronic transitions.
[en] The United States is in the midst of an energy revolution, spurred by advancement of technology to produce unprecedented supplies of oil and natural gas. Simultaneously, there is an increasing concern for climate change attributed to greenhouse gas (GHG) emissions that, in large part, result from burning fossil fuels. An international consensus has concluded that the U.S. and other developed nations have an imperative to reduce GHG emissions to address these climate change concerns. The global desire to reduce GHG emissions has led to the development and deployment of clean energy resources and technologies, particularly renewable energy technologies, at a rapid rate. At the same time, each of the major energy sectors-the electric grid, industrial manufacturing, transportation, and the residential/commercial consumers- is increasingly becoming linked through information and communications technologies, advanced modeling and simulation, and controls. Coordination of clean energy generation technologies through integrated hybrid energy systems, as defined below, has the potential to further revolutionize energy services at the system level by coordinating the exchange of energy currency among the energy sectors in a manner that optimizes financial efficiency (including capital investments), maximizes thermodynamic efficiency (through best use of exergy, which is the potential to use the available energy in producing energy services), reduces environmental impacts when clean energy inputs are maximized, and provides resources for grid management. Rapid buildout of renewable technologies has been largely driven by local, state, and federal policies, such as renewable portfolio standards and production tax credits that incentivize investment in these generation sources. A foundational assumption within this program plan is that renewable technologies will continue to be major contributors to the future U.S. energy infrastructure. While increased use of clean renewable technologies will aid in achieving reduced GHG emissions, it also presents new challenges to grid management that must be addressed. These challenges primarily derive from the fundamental characteristics of variable renewable generators, such as wind and solar: non-dispatchability, variable production, and reduced electromechanical inertia. This document presents a preliminary research and development (R&D) plan for detailed dynamic simulation and analysis of nuclear-renewable hybrid energy systems (N-R HES), coupled with integrated energy system design, component development, and integrated systems testing. N-R HES are cooperatively-controlled systems that dynamically apportion thermal and/or electrical energy to provide responsive generation to the power grid.
[en] The paper presents the results of calculated research on determining the thermal technical indicators of a combined solar desalinization and drying plant. The structure of the plant is developed and proposed. A mathematical model is developed that describes the thermal processes occurring in the plant based on heat-balance equations solved using the Laplace method.
[en] This talk is for the ARPA-E funded program that Los Alamos is part of a team with Carnegie Mellon University, Magnetics div. of Spang, and the University of Pittsburgh. Most of the material presented in this talk has been presented before and is associated with accelerators and has a 'DUSA' 'ATDO' designator. Slight variations in circuit topology as presented here are somewhat novel and although not classified should be considered Los Alamos proprietary. The viewgraphs from 'both' talks will be presented to team members and the ARPA-E sponsor.
[en] The Legacy Management (LM) Program has responsibility for management of over 85 post-closure sites across the United States. The program was formed through a consolidation of AEC/DOE sites being managed under separate programs and with diverse geography, regulatory bases, residual contaminants, and operating histories. Through development and implementation of a nation-wide program to ensure public safety, remedy performance, compliance, records management and ongoing stakeholder communication, the program has become efficient at meeting post-closure responsibilities and effective at proactively turning these liabilities into assets. (author)
[en] The future trends of the industry require major renovations in the infrastructure of transmission, distribution, and storing of generated energy. With the increased use of renewable energy across the globe, energy storage (ES) systems have started to play a prominent role in shaping the future of the ES market. However, because of the uneven distribution of the renewable energy throughout the world, more emphasis must be made to the integration of power grids with the ES devices to utilize the excess power more effectively. In this paper, a study is performed regarding the integration of a hybrid system, consisting of a lithium-ion battery (LIB) and superconducting magnetic energy storage (SMES), into an interconnected microgrid operation. The structure of a microgrid is explained by analyzing the selected battery (LIB) and voltage source converter (VSC)-based SMES unit via MATLAB & Simulink. Finally, the voltage waveforms are compared and discussed in detail.
[en] The photoelectron spectrum of CeO− exhibits what appears to be a single predominant electronic transition over an energy range in which numerous close-lying electronic states of CeO neutral are well known. The photoelectron spectrum of Ce(OH)2−, a molecule in which the Ce atom shares the same formal oxidation state as the Ce atom in CeO−, also exhibits what appears to be a single transition. From the spectra, the adiabatic electron affinities of CeO and Ce(OH)2 are determined to be 0.936 ± 0.007 eV and 0.69 ± 0.03 eV, respectively. From the electron affinity of CeO, the CeO− bond dissociation energy was determined to be 7.7 eV, 0.5 eV lower than the neutral bond dissociation energy. The ground state orbital occupancies of both CeO− and Ce(OH)2− are calculated to have 4f 6s2 Ce+ superconfigurations, with open-shell states having 4f5d6s superconfiguration predicted to be over 1 eV higher in energy. Low-intensity transitions observed at higher electron binding energies in the spectrum of CeO− are tentatively assigned to the 1Σ+ (Ω = 0) state of CeO with the Ce+2⍰6s2 superconfiguration
[en] Thin PbxSn1−xS films are obtained by the “hot-wall” method at substrate temperatures of 210–330°C. The microstructure, composition, morphology, and electrical characteristics of films are investigated. On the basis of the obtained films, photosensitive In/p-PbxSn1−xS Schottky barriers are fabricated for the first time. The photosensivity spectra of these structures are investigated, and the character of interband transitions and the band-gap values are determined from them. The conclusion is drawn that PbxSn1−xS thin polycrystalline films may be used in solar-energy converters.
[en] The use of a low-power solar network and standalone power plants is the most promising for the needs of the housing and utilities sector, small industrial enterprises, social and public health facilities, recreation areas, remote objects, and agricultural industries; this will make it possible to reduce the load on the energy system at peak moments, as well as to decrease losses when transporting electric energy in its elements. It is assumed that the minimum value of the unit cost of generated electric energy is used as the criterion for configuring and selecting the parameters of solar power equipment, which will make it possible to set up an economically feasible additional power supply to the consumer, since it excludes the use of storage devices and rearrangement of the power supply system.