2,837 research outputs found
Space-enhanced terrestrial solar power for equatorial regions
This Paper investigates the concept of solar mirrors in an Earth orbit to provide large-scale terrestrial equatorial solar farms with additional solar power during the hours of darkness. A flower constellation of mirrors is considered in highly eccentric orbits (semimajor axis=20,270.4 km) in order to increase the time of visibility over the solar farms, and through this architecture, only two mirrors are needed to provide complete night coverage over three equatorial locations. Selecting the proper value for the orbit eccentricity, solar radiation pressure and Earth’s oblateness perturbations act on the mirrors so that the apsidal motion of the orbit due to these perturbations is synchronized with the apparent motion of the sun. Therefore, it can be guaranteed that the perigee always points toward the sun and that the mirrors orbit mostly above the night side of the Earth. With respect to geostationary orbit, the family of orbits considered in this Paper allows a passive means to overcome issues related to orbital perturbations. Moreover, because of the large slant range from geostationary orbits, a larger mirror is required to deliver the same energy that could be delivered from a lower orbit with a smaller mirror. As a result, a single antiheliotropic flower constellation composed of two mirrors of 50 km2 would be able to deliver energy in the range of 4.60–5.20 GW·h per day to 1000 km3 solar farms on the equator. Finally, it is estimated that, deploying 90 of these constellations, the price of electricity could be reduced from 9.1 cents to 6 cents per kW⋅h
Multiple input control strategies for robust and adaptive climate engineering in a low order 3-box model
A low-order 3-box energy balance model for the climate system is employed with a multivariable control scheme for the evaluation of new robust and adaptive climate engineering strategies using solar radiation management. The climate engineering measures are deployed in three boxes thus representing northern, southern and central bands. It is shown that, through heat transport between the boxes, it is possible to effect a degree of latitudinal control through the reduction of insolation. The approach employed consists of a closed-loop system with an adaptive controller, where the required control intervention is estimated under the RCP4.5 radiative scenario. Through the online estimation of the controller parameters, adaptive control can overcome key issues related to uncertainties of the climate model, the external radiative forcing and the dynamics of the actuator used. In fact, the use of adaptive control offers a robust means of dealing with unforeseeable abrupt perturbations, as well as the parametrization of the model considered, to counteract the RCP4.5 scenario, while still providing bounds on stability and control performance. Moreover, applying multivariable control theory also allows the formal controllability and observability of the system to be investigated in order to identify all feasible control strategies
Spontaneous heavy cluster emission rates using microscopic potentials
The nuclear cluster radioactivities have been studied theoretically in the
framework of a microscopic superasymmetric fission model (MSAFM). The nuclear
interaction potentials required for binary cold fission processes are
calculated by folding in the density distribution functions of the two
fragments with a realistic effective interaction. The microscopic nuclear
potential thus obtained has been used to calculate the action integral within
the WKB approximation. The calculated half lives of the present MSAFM
calculations are found to be in good agreement over a wide range of observed
experimental data.Comment: 4 pages, 4 figure
Do Superordinate Identification and Temporal/Social Comparisons Independently Predict Citizens’ System Trust? Evidence From a 40-Nation Survey
Do superordinate in-group bias as well as temporal and social comparisons offer standalone explanations for system justification? We addressed this question using the latest World Value Survey (7th Wave), combining the responses of 55,721 participants from 40 different nations. Results from a random slope multilevel model showed that superordinate (national) identification, temporal comparison (i.e., the outcomes of an individual relative to those of his/her parents at different time points), and social comparison (based on income levels) were independent and positive predictors of system justification. Specifically, system justification increased when national identification was high, when income increased (i.e., the socioeconomic comparison was positive), and when the outcomes of citizens improved relative to the outcomes of their parents at relevant time points (i.e., the temporal comparison was positive). Incidentally, we also observed an interaction between national identification and temporal comparison (but not with social comparison), indicating that positive temporal comparison seemed to have a reduced effect (but still significant) for highly identified citizens. These results are supportive of the social identity approach to system justification and suggest that support for societal systems is a positive function of people’s personal and group interests
Intergroup alliance orientation among intermediate-status group members: The role of stability of social stratification
Three studies have tested the hypothesis that intermediate-status groups are more oriented to ally with outgroups when their social position is under threat. In study 1, participants believed that their ingroup was intermediate in status and social stratification was manipulated as either stable or status-detrimental unstable. Results indicated that participants were more likely to seek alliances a) with a high-status group and b) when social stratification was status-detrimental unstable. Study 2 showed that participants were more likely to seek alliances with a lower status group when social stratification was status-detrimental unstable rather than stable, while they were supportive of policies helping disadvantaged groups regardless of the stability of social stratification. Study 3 showed that when social stratification was status-detrimental unstable, intermediate-status group members were more oriented to ally with a low-status group, equally supportive of policies helping disadvantaged groups, but less oriented to supplying direct help to a low-status group
Ingroup identification, hope and system justification: Testing hypothesis from social identity model of system attitudes (SIMSA) in a sample of LGBTQIA+ individuals
The social identity model of system attitudes (SIMSA) suggests that system justification among low-status groups can be explained by ingroup identification and the hope for a collective future improvement. In this report, we summarize the results of a cross-sectional investigation concerning the relationship between system justification, hope and identification based on a sample of 200 LGBTQIA+ individuals (identifying themselves as non-normative with respect to gender identity and sexual orientation). The results were supportive of SIMSA expectations and showed that system justification was positively linked to hope for future advancement. Importantly, hope played a key role influencing the relations between ingroup identification and perceived ingroup status: for low-status individuals who had high hope, ingroup identification was positively associated with system justification. Limits are acknowledged
Universal decay law in charged-particle emission and exotic cluster radioactivity
A linear universal decay formula is presented starting from the microscopic
mechanism of the charged-particle emission. It relates the half-lives of
monopole radioactive decays with the -values of the outgoing particles as
well as the masses and charges of the nuclei involved in the decay. This
relation is found to be a generalization of the Geiger-Nuttall law in
radioactivity and explains well all known cluster decays. Predictions on the
most likely emissions of various clusters are presented.Comment: 2 figure
Huge Seebeck coefficients in non-aqueous electrolytes
The Seeebeck coefficients of the non-aqueous electrolytes tetrabutylammonium
nitrate, tetraoctylphosphonium bromide and tetradodecylammonium nitrate in
1-octanol, 1-dodecanol and ethylene-glycol are measured in a temperature range
from T=30 to T=45 C. The Seebeck coefficient is generally of the order of a few
hundreds of microvolts per Kelvin for aqueous solution of inorganic ions. Here
we report huge values of 7 mV/K at 0.1M concentration for tetrabutylammonium
nitrate in 1-dodecanol. These striking results open the question of
unexpectedly large kosmotrope or "structure making" effects of
tetraalkylammonium ions on the structure of alcohols.Comment: Submitted to J. Chem. Phy
Performance of a Y-Ba-Cu-O superconducting filter/GaAs low noise amplifier hybrid circuit
A superconducting 7.3 GHz two-pole microstrip bandpass filter and a GaAs low noise amplifier (LNA) were combined into an active circuit and characterized at liquid nitrogen temperatures. This superconducting/semiconducting circuit's performance was compared to a gold filter/GaAs LNA hybrid circuit. The superconducting filter/GaAs LNA hybrid circuit showed higher gain and lower noise figure than its gold counterpart
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