In the context of climate change, salinity intrusion into rivers has been, and will be, one of the most important issues for coastal water resources management. A combination of changes, including ...increased temperature, change in regional rainfall, especially sea level rise (SLR) related to climate change, will have significant impacts on this phenomenon. This paper presents the outcomes of a study conducted in the Mekong Delta of Vietnam (MKD) for evaluating the effect of sea water intrusion under a new SLR scenario. Salinity intrusion was simulated by one-dimensional (1D) modeling. The relative sea level projection was constructed corresponding to the RCP 6.0 emission scenario for MKD based on the statistical downscaling method. The sea level in 2050 is projected to increase from 25 cm to 30 cm compared to the baseline period (in 2000). Furthermore, the simulated results suggested that salinity greater than 4 g/l, which affects rice yield, will intrude up to 50-60 km into the river. Approximately 30,000 ha of agricultural area will be affected if the sea level rise is 30 cm.
Chiral spin textures of a ferromagnetic layer in contact to a heavy non-magnetic metal, such as Néel-type domain walls and skyrmions, have been studied intensively because of their potential for ...future nanomagnetic devices. The Dyzaloshinskii-Moriya interaction (DMI) is an essential phenomenon for the formation of such chiral spin textures. In spite of recent theoretical progress aiming at understanding the microscopic origin of the DMI, an experimental investigation unravelling the physics at stake is still required. Here we experimentally demonstrate the close correlation of the DMI with the anisotropy of the orbital magnetic moment and with the magnetic dipole moment of the ferromagnetic metal in addition to Heisenberg exchange. The density functional theory and the tight-binding model calculations reveal that inversion symmetry breaking with spin-orbit coupling gives rise to the orbital-related correlation. Our study provides the experimental connection between the orbital physics and the spin-orbit-related phenomena, such as DMI.
A topology optimization method is proposed for transient response problems involving thermoelastic models, where the objective is to optimize the structure considering time-dependent dynamic and ...thermal loads. The proposed method can be applied to problems involving thermal deformation and stress, which damage heated machine parts. This paper presents a transient response analysis of a thermoelastic model subjected to mechanical and thermal loads having arbitrary profiles with respect to time. This can be formulated as a multi-objective optimization problem to obtain a structure that minimizes the deformation and maximum stress. A sensitivity analysis was conducted by using the adjoint variable method and the discretize-then-differentiate approach. The proposed method was applied to numerical examples for validation.
•A topology optimization method considering transient response is presented.•The objective is to optimize the structure considering time-dependent loads.•The discretize-then-differentiate approach is used in the sensitivity analysis.
Experimental ground-state combination differences of CH5 Asvany, Oskar; Yamada, Koichi M. T.; Brünken, Sandra ...
Science (American Association for the Advancement of Science),
03/2015, Letnik:
347, Številka:
6228
Journal Article
Recenzirano
Protonation of methane (CH4), a rather rigid molecule well described by quantum mechanics, produces CH5+, a prototypical floppy molecule that has eluded definitive spectroscopic description. ...Experimental measurement of high-resolution spectra of pure CH5+ samples poses a formidable challenge. By applying two types of action spectroscopy predicated on photoinduced reaction with CO2 and photoinhibition of helium cluster growth, we obtained low-temperature, high-resolution spectra of mass-selected CH5+. On the basis of the very high accuracy of the line positions, we determined a spectrum of combination differences. Analysis of this spectrum enabled derivation of equally accurate ground state–level schemes of the corresponding nuclear spin isomers of CH5+, as well as tentative quantum number assignment of this enfant terrible of molecular spectroscopy.
In this study, we propose a new topology optimization problem for creep deformation minimization. It is a phenomenon in which deformation progresses even when the load is constant, and is a cause of ...damage to mechanical parts. Therefore, the results of this paper will be one of the solutions to the problem of creep deformation. We deal with a viscoelastic model assuming the generalized Maxwell model to account for creep deformation. In addition, we devise a new objective function that directly evaluate the creep deformation. Since sensitivity analysis of the objective function is necessary for topology optimization, we formulate the sensitivity of the viscoelastic model to accurately consider the time dependence. The relationship between the creep characteristics and the objective function is explained through a numerical example using a one-dimensional model. By examining a two-dimensional model, it is shown that the formulated sensitivity is validated and the proposed method derives the optimized configuration under which creep deformation is minimized.
•We propose a topology optimization for minimizing creep deformation.•We apply the generalized Maxwell model to simulate creep deformation.•A new optimization problem that enables creep deformation minimization is introduced.•We present a sensitivity analysis that considers the history dependency of deformation.
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