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The Vietnamese Mekong Delta (VMD) is highly vulnerable to drought, particularly in the context of climate change. Prolonged drought during the dry season has emerged as a significant natural disaster, severely affecting agriculture and socioeconomic development in the region. To enhance water resource management and agricultural productivity, this study examines the characteristics of meteorological droughts using the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI) in the upper Mekong Delta of Vietnam. The Mann–Kendall (MK) test and Sen's slope were employed to assess trends in drought and hydrological conditions. The results reveal no significant trends in rainfall, while average temperatures have increased significantly in most months, especially during the dry season. Although water levels and discharge at the Tan Chau and Chau Doc stations have decreased, significant reductions were primarily observed at Chau Doc station from 2000 to 2021. These findings provide critical insights for sustainable water resource management and planning in the VMD, considering future climate variability and changes in hydrological regimes. [ABSTRACT FROM AUTHOR]

In this study, cellulose aerogel (CA) was synthesized from coir by the sol-gel method and applied for methylene blue (MB) removal in water. The CA materials have relatively low densities of 46.36–58.53 mg/cm3. In particular, the CA material with a coir content of 30 g/L composed of many porous fibers had the highest porosity of 96.97% and methylene blue (MB) adsorption capacity of 142.02 mg/g. In order to improve the adsorption capacity, the CA was then pyrolyzed in N2 gas and activated by KOH to produce activated carbon cellulose aerogel (ACCA). The adsorption capacity of ACCA material was 3.6 times higher than the CA precursor. The adsorption process of MB using CA and ACCA follows the Langmuir isotherm model and pseudo-second-order kinetic. The study results show the potential to activate carbon cellulose aerogel for dye treatment in industrial wastewater. [ABSTRACT FROM AUTHOR]

This paper studies the plane constrained shear problem for single crystals having one active slip system and subjected to loading in both directions within the small strain thermodynamic dislocation theory proposed by Le (J Mech Phys Solids 111:157–169, 2018). The numerical solution of the boundary value problem shows the combined isotropic and kinematic work hardening, the sensitivity of the stress–strain curves to temperature and strain rate, the Bauschinger effect, and the size effect. [ABSTRACT FROM AUTHOR]

The present paper studies non-uniform plastic deformations of crystals undergoing anti-plane constrained shear. The asymptotically exact energy density of crystals containing a moderately large density of excess dislocations is found by the averaging procedure. This energy density is extrapolated to the cases of extremely small or large dislocation densities. Taking into account the configurational temperature and the density of redundant dislocations, we develop the thermodynamic dislocation theory for non-uniform plastic deformations and use it to predict stress-strain curves and dislocation densities. [ABSTRACT FROM AUTHOR]

By using a numerical model for a selective laser melting process, this study investigates the melt pool behaviours and the resulting defects due to different scanning strategies. Two common scanning patterns were tested: sequential and boustrophedon. The study found that sequential scanning strategy leads to a non-flat printed surface, while the boustrophedon strategy produces a flat printed surface. At the beginning of the track, the molten material is pulled from the hot laser spot to the cold tail by the Marangoni force leading to an increase in the melt pool height of the sequential and alternated strategies. On the other hand, due to the deep keyhole and the high cooling rate when the laser is switched off, a recess is formed at the end of the tracks. Similar phenomena can be observed in the boustrophedon scanning strategy at the start and ending of the track. [ABSTRACT FROM AUTHOR]

This paper derives the equations of amplitude modulation of shallow water waves from the scalar Boussinesq's (BSQ) equation by using the variational-asymptotic method. Two asymptotic solutions describing the amplitude modulation of trains of solitons and of positons are obtained. The comparison with the exact solutions of BSQ equation shows quite excellent agreement. [ABSTRACT FROM AUTHOR]

We propose a thermodynamically consistent model of static and dynamic recrystallization for metals during and after severe plastic deformations that is capable of predicting the evolution of dislocation density as well as mean grain size. [ABSTRACT FROM AUTHOR]

In the last few years, a significant number of multi-objective metaheuristics have been proposed in the literature in order to address real-world problems. Local search methods play a major role in many of these metaheuristic procedures. In this paper, we adapt a recent and popular indicator-based selection method proposed by Zitzler and Künzli in 2004, in order to define a population-based multi-objective local search. The proposed algorithm is designed in order to be easily adaptable, parameter independent and to have a high convergence rate. In order to evaluate the capacity of our algorithm to reach these goals, a large part of the paper is dedicated to experiments. Three combinatorial optimisation problems are tested: a flow shop problem, a ring star problem and a nurse scheduling problem. The experiments show that our algorithm can be applied with success to different types of multi-objective optimisation problems and that it outperforms some classical metaheuristics. Furthermore, the parameter sensitivity analysis enables us to provide some useful guidelines about how to set the parameters. [ABSTRACT FROM AUTHOR]

Ovarian cancers migrate and metastasize over the surface of the peritoneal cavity. Consequently, dysregulation of mechanisms that limit cell migration may be particularly important in the pathogenesis of the disease. ARHI is an imprinted tumor-suppressor gene that is downregulated in >60% of ovarian cancers, and its loss is associated with decreased progression-free survival. ARHI encodes a 26-kDa GTPase with homology to Ras. In contrast to Ras, ARHI inhibits cell growth, but whether it also regulates cell motility has not been studied previously. Here we report that re-expression of ARHI decreases the motility of IL-6- and epidermal growth factor (EGF)-stimulated SKOv3 and Hey ovarian cancer cells, inhibiting both chemotaxis and haptotaxis. ARHI binds to and sequesters Stat3 in the cytoplasm, preventing its translocation to the nucleus and localization in focal adhesion complexes. Stat3 siRNA or the JAK2 inhibitor AG490 produced similar inhibition of motility. However, the combination of ARHI expression with Stat3 knockdown or inhibition produced greatest inhibition in ovarian cancer cell migration, consistent with Stat3-dependent and Stat3-independent mechanisms. Consistent with two distinct signaling pathways, knockdown of Stat3 selectively inhibited IL-6-stimulated migration, whereas knockdown of focal adhesion kinase (FAK) preferentially inhibited EGF-stimulated migration. In EGF-stimulated ovarian cancer cells, re-expression of ARHI inhibited FAKY397 and SrcY416 phosphorylation, disrupted focal adhesions, and blocked FAK-mediated RhoA signaling, resulting in decreased levels of GTP-RhoA. Re-expression of ARHI also disrupted the formation of actin stress fibers in a FAK- and RhoA-dependent manner. Thus, ARHI has a critical and previously uncharacterized role in the regulation of ovarian cancer cell migration, exerting inhibitory effects on two distinct signaling pathways. [ABSTRACT FROM AUTHOR]

Within continuum dislocation theory, one-dimensional energy functional of a bent beam, made of a single crystal, is derived. By relaxing the continuously differentiable minimizer of this energy functional, we construct a sequence of piecewise smooth deflections and piecewise constant plastic distortions reducing the energy and exhibiting polygonization. The number of polygons can be estimated by comparing the surface energy of small angle tilt boundaries with the contribution of the gradient terms from the weak minimizer in the bulk energy. [ABSTRACT FROM AUTHOR]

The paper aims at studying the dislocation nucleation, the corresponding work hardening and the influence of resistance to the dislocation motion within the framework of continuum theory of dislocations. We consider an anti-plane constrained shear problem which admits an analytical solution. The interesting features of this solution are the energy and dissipation thresholds for dislocation nucleation, the Bauschinger translational work hardening, and the size effect. [ABSTRACT FROM AUTHOR]

An initiation criterion and a kinetic relation describing hysteresis in shape memory alloys consistent with non-equilibrium thermodynamics are proposed. The initiation of phase transition begins always at zero driving force, defined as the negative derivative of free energy with respect to the volume fraction of high strain phase. The kinetic relation is obtained from the dissipation potential which is proportional to the magnitude of the volume fraction rate times the newly formed volume fraction. The proposed theory turns out to be rate-independent, but history dependent, and can describe all features of hysteresis loops observed in experiments. [ABSTRACT FROM AUTHOR]

An analytical formula for the energy distribution of a neutral gas of point vortices is obtained. Good agreement with the numerical results of Campbell and O'Neil is found. [ABSTRACT FROM AUTHOR]

A variational principle is formulated for a body containing a crack in equilibrium. An expression for the driving force acting on the crack admitting nontangential virtual crack extensions is derived. As a consequence of a variational principle, crack equilibrium criterion under mixed-mode loading conditions is obtained. For general 3-D problems, the magnitude as well as the direction of the driving force are precisely determined. Fracture locus for three combined modes is calculated. [ABSTRACT FROM AUTHOR]

Within the framework of classical mechanics and field theories, equivalent sets of balance equations and entropy production inequality are formulated in spatial, referential and intermediate description for an elastoplastic body at finite strain. The entropy production inequality formulated with respect to the intermediate configuration together with an assumption about the functional form of the free energy are used to substantiate new constitutive equations. Special attention is focused to the cases of small elastic/large plastic strain deformation (metal plasticity) and rigid-plastic deformation. [ABSTRACT FROM AUTHOR]

A variational principle of total energy is formulated for finite strain statics of a hyperelastic body whose initial configuration contains a gap. From this principle statical equations and boundary conditions for the gapped body are derived. The equilibrium condition at a gap tip is associated with the well-known J-integrals. By including the reaction of inertia and the flux of kinetic energy the principle of total energy is transformed to the variational inequality of evolution for dynamics of a hyperelastic body with a propagating crack. A closed system of dynamical equations, boundary conditions and additional conditions on the unknown contact crack surfaces and crack tip is obtained. As example the antiplane shear of an infinite gapped body is considered. [ABSTRACT FROM AUTHOR]