ABSTRACT
This paper presents a numeric study of the dynamic stabilization of the ablative Rayleigh-Taylor instability (ARTI) in the presence of a temporally modulated laser pulse. The results show that the specially modulated laser produces a dynamically stabilized configuration near the ablation front. The physical features of the relevant laser-driven parameters in the unperturbed ablative flows have been analyzed to reveal the inherent stability mechanism underlying the dynamically stabilized configuration. A single-mode ARTI for the modulated laser pulse is first compared with that of the unmodulated laser pulse. The results show that the modulated laser stabilizes the surface perturbations and reduces the linear growth rate and enhancement of the cutoff wavelength. For multimode perturbations, the dynamic stabilization effect of the modulated laser pulse contributes to suppress the small-scale structure and reduce the width of the mixing layer. Moreover, the results show that the stabilization effect of the modulated laser pulse decreases as the maximum wavelength increases.
ABSTRACT
Virtual water is an important indicator measuring the amount of water needed from the perspective of consumption, which can help decision makers to identify desired system design and optimal management strategy against water resources shortage. In this study, a novel model named as factorial ecologically-extended input-output model (abbreviated as FEIOM) is developed for virtual water management. FEIOM integrates techniques of input-output model (IOM), ecological network analysis (ENA) and factorial analysis (FA) into a general framework. It is effective to evaluate the virtual water flows, reveal ecological inter-connections in virtual water system (VWS), and identify key water consumption sectors that have significant individual and interactive effects on VWS's performance. FEIOM is then applied to identifying optimal virtual water management strategies for Kazakhstan in Central Asia. The main findings are: (i) Kazakhstan is a net importer of virtual water (reaching up to 46.0 × 109 m3), demonstrating that the national economic structure is reasonable, which can abate the national water scarcity and improve its eco-environmental protection; (ii) the virtual water of agricultural sector is net exporter, where vegetables, fruits and nuts occupy 86% of the total agricultural exports; the massive export of water-intensive products further squeezes the water for other users; (iii) the key factors affecting the national VWS are agriculture > primary manufacturing > advanced manufacturing > services. Therefore, from solving water resources shortage and facilitating sustainable development perspectives, Kazakhstan should stimulate the domestic primary manufacturing productions and improve agriculture and advanced manufacturing water-use efficiencies.
Subject(s)
Water Supply , Water , Agriculture , China , Kazakhstan , Water ResourcesABSTRACT
In this study, a fuzzy-vertex-based virtual-water analysis method (FVAM) is developed for assessing the virtual water content (VWC) of main agricultural products, imports, and exports at a national scale. FVAM has advantages in quantifying state-level VWC with a bottom-up approach and reflecting uncertain parameters based on vertex analysis technique. FVAM is applied to a real case of Kazakhstan in Central Asia. Results reveal that (i) the VWC of Kazakhstan's agricultural products is between 55.61 and 83.98 billion m3/yr in 2000-2016, where wheat is the largest water consumer and the Kostanay state has the largest VWC; (ii) Kazakhstan is a net exporter of virtual water, most of which flows to neighboring countries such as Russia and Azerbaijan; (iii) uncertainties in crop coefficient (Kc), feed water requirement (FWR), drinking water requirement (DWR) and service water requirement (SWR) can affect the VWC assessment; (iv) the massive export of water-intensive products makes the water resources more severe in Kazakhstan, which further squeezes the local ecological water use. Therefore, reducing the export of virtual water should be the focus of future agricultural policies. The findings are useful for decision makers to optimize Kazakhstan's agricultural structure, mitigate the national water scarcity, and facilitate the regional sustainable development.
ABSTRACT
A novel inversion technique is proposed to unfold core asymmetries at the source with x-ray emission images, which were obtained from imploded surrogate capsules in symmetry diagnostic experiments. The axisymmetrical core emission can be expanded as a Fourier series, with Legendre polynomials and spherical Bessel functions as bases concerned with polar angle and radius, respectively. A least-squares estimator is employed to obtain the unknown coefficients from its two-dimensional image data. The unfolded Legendre coefficients can be further used to test modeling of drive asymmetries in hohlraums. This technique is also demonstrated with a proof-of-principle experiment performed on the Shenguang II laser facility [L. Zunqi et al., Chin. J. Lasers B10, 6 (2001)].
