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[en] Secular and long-term periodic changes in surface temperature cause perturbations to the geothermal gradient which may be significant to depths of at least 1000 m, and major corrections are required to determine absolute values of heat flow from the Earth's interior. However, detailed climatic models remain contentious and estimates of error in geothermal gradients differ widely. Consequently, regions of anomalous heat flow which could contain geothermal resources may be more easily resolved by measuring relative values at a standard depth (e.g. 100 m) so that all data are subject to similar corrections. (orig./ME)
[en] Geothermal studies have been conducted in China continuosly since the end of the 1950's with renewed activity since 1970. Three areas of research are defined: (1) fundamental theoretical research of geothermics, including subsurface temperatures, terrestrial heat flow and geothermal modeling; (2) exploration for geothermal resources and exploitation of geothermal energy; (3) geothermal studies in mines. (orig./ME)
[en] A novel nuclear astrophysics facility, CLAIRE (Center for Low Energy Astrophysics and Interdisciplinary REsearch), is being designed at Lawrence Berkeley National Laboratory to address the need for precise fusion cross section measurements at near-solar energies (∼20 keV). At these low energies, fusion cross sections decrease exponentially with energy and are expected to approach femtobarn levels or less. In order to measure such small cross sections, the CLAIRE facility will incorporate a versatile accelerator capable of transporting high current (>100 mA), low energy (50-300 keV) ion beams with a tight focus (<1 cm) to a cooled, dense gas-jet target. The conceptual design for this accelerator is discussed, and simulations of both beam extraction and transport are presented
[en] The unified global energy dependence of the induced fission times obtained by the experimental crystal blocking technique for nuclei with Z=91-94 in the range of initial excitation energy from 5 to 250 MeV was analyzed. It was demonstrated that for the energies up to 60-70 MeV the fission times can be described in the frame of the statistical theory taking into account the double-humped structure of the fission barrier and the lifetimes of both classes of excited nuclear states realized in the first and second potential wells. However, for the excitation energies above 70 MeV it is needed to consider the dynamical effects in fission channel
[en] There are numerous indications that solar energy is far more than a mere stopgap measure to escape from the present environmental crisis. These include the natural as well as the developed, and still developing, technological potential of solar energy; the vast opportunities offered by abandoning destructive energy sources; and, not least, the new industrial perspectives arising from the conversion of our energy system. In addition to the environmental benefits, solar energy will bring about major economic and social gains. The creation of a solar energy system offers an unexpected and unique chance to release industrial society from the harmful consequences of the Industrial Revolution and to make available its positive accomplishments - particularly the social, democratic and cultural opportunities made possible by freeing mankind from slave labour - to all of mankind. Destruction of the environment is the greatest danger for industrialized societies pursuing economic growth, but it is not the only one. The Western high culture of welfare states is evidently a thing of the past. Created by the pressure of social movements that emerged in the Industrial Revolution, they stabilized capitalism by making it more responsive to the social needs in its strongholds. But both old and new contradictions, as well as the growth of welfare costs, lead to the conclusion that the future of the industrial system is increasingly seen only in terms of jettisoning its social obligations. Political democracy will then once more be in danger. Modern history is unable to provide an example of a stable democracy based on permanent mass misery
[en] In simulation of fluid injection in fractured geothermal reservoirs, the characteristics of the physical processes are severely affected by the local occurence of connected fractures. To resolve these structurally dominated processes, there is a need to develop discretization strategies that also limit computational effort. In this paper, we present an upscaling methodology for geothermal heat transport with fractures represented explicitly in the computational grid. The heat transport is modeled by an advection-conduction equation for the temperature, and solved on a highly irregular coarse grid that preserves the fracture heterogeneity. The upscaling is based on different strategies for the advective term and the conductive term. The coarse scale advective term is constructed from sums of fine scale fluxes, whereas the coarse scale conductive term is constructed based on numerically computed basis functions. The method naturally incorporates the coupling between solution variables in the matrix and in the fractures, respectively, via the discretization. In this way, explicit transfer terms that couple fracture and matrix solution variables are avoided. Numerical results show that the upscaling methodology performs well, in particular for large upscaling ratios, and that it is applicable also to highly complex fracture networks.
[en] I use a simple model to parameterize mirror energy differences for several nuclei with N=8 or 10 and their mirrors with Z=8 or 10. I then use the results of the fit to predict the energy of the ground state of the unbound nucleus 15Ne: E2p=2.68(24) MeV.
[en] The large penetration of wind farm into interconnected power systems may cause the severe problem of tie-line power oscillations. To suppress power oscillations, the superconducting magnetic energy storage (SMES) which is able to control active and reactive powers simultaneously, can be applied. On the other hand, several generating and loading conditions, variation of system parameters, etc., cause uncertainties in the system. The SMES controller designed without considering system uncertainties may fail to suppress power oscillations. To enhance the robustness of SMES controller against system uncertainties, this paper proposes a robust control design of SMES by taking system uncertainties into account. The inverse additive perturbation is applied to represent the unstructured system uncertainties and included in power system modeling. The configuration of active and reactive power controllers is the first-order lead-lag compensator with single input feedback. To tune the controller parameters, the optimization problem is formulated based on the enhancement of robust stability margin. The particle swarm optimization is used to solve the problem and achieve the controller parameters. Simulation studies in the six-area interconnected power system with wind farms confirm the robustness of the proposed SMES under various operating conditions
[en] Pairing reduction in deformed nuclei due to the blocking effect is treated exactly with the particle-number-conserving method. Merely due to the blocking effect the gap parameter Δ becomes configuration-dependent. The pairing reduction delta(ν0) depends sensitively on the location of the blocked level ν0 relative to the Fermi surface, lambda, and decreases rapidly with vertical strokeepsilonν0lambdavertical stroke. The pairing reduction delta(ν0) depends also sensitively on the single-particle level distribution near the Fermi surface. In some special cases pairing reduction may be negative. With an increasing number of the blocked levels (above the Fermi surface) the gap parameter Δ decreases dramatically. If the blocked levels are below the Fermi surface the situation is quite different and as the number of the blocked levels becomes sufficiently large the pairing reduction may vanish. (orig.)