Earthquake‐induced hydrodynamic pressures on a 3D rigid dam–reservoir system using DRBEM and a radiation matrix

The dual reciprocity method is applied to determine the hydrodynamic pressure distribution in a three‐dimensional dam–reservoir system subjected to earthquake excitation. The reservoir domain is idealized as a finite region of irregular geometry adjacent to the dam followed by an infinite domain of uniform cross‐section in the upstream direction. The reservoir hydrodynamic pressure response is governed by the Helmholtz equation subject to free surface, dam–reservoir interface, absorbing bottom/banks and radiation boundary conditions. A three‐dimensional (3D) dual reciprocity model is developed to determine the hydrodynamic pressure in the finite reservoir domain. A radiation matrix is developed and introduced to relate the hydrodynamic pressure and its normal derivative on the interface between the finite and infinite domains. The three‐dimensional radiation model used is developed by applying a two‐dimensional dual reciprocity formulation along the interface of the finite and infinite reservoirs together with a continuum solution in the upstream direction of the infinite domain. The model is compared for the hydrodynamic response of a three‐dimensional rectangular reservoir and found to be in excellent agreement with results obtained from a model based on the analytical formulation existing in the literature. Copyright © 2003 John Wiley & Sons, Ltd.     

Multicriteria Analysis For Water Productivity in the Jordan Valley

Abstract

Multiple variables associated with agricultural sector, including crop water consumption, salinity tolerance, marketing, evapotranspiration and other factors related to industrial sector, were incorporated into a multi-criteria analysis (MCA). The MCA utilized Analytical Hierarchy Process (AHP) which resulted in the prioritization of water use for management in the Jordan Valley. The inputs to the MCA were generated through metrological variables for the Jordan Valley for the period 1980 to 1999. Soil data and crop data were evaluated using the EVAPOT program, the KCISA program, and the ISAREG model to estimate reference evapotranspiration, crop coefficiency, crop water requirement, and calculations of water productivity for agricultural and industrial sectors. The results of the MCA make recommendations for enhancing long-term sustainability of water resources in the Jordan Valley, while allowing for water utilization and economic growth. The MCA ranked the date palm as the highest priority crop with respect to the goal of sustainable agricultural use of water. Apparel manufacturing was the most sustainable industry. Overall, the industrial sector seems to perform better with regards to water productivity than the agricultural sector. It can be concluded that the MCA tool and ISAREG model are potentially positive contributions to the process of decision- making for selection and ranking of alternatives for help in solving problems that include conflicting criteria.     

An improved approximation for the Nakagami-m inverse CDF using artificial bee colony optimization

Wireless Networks - The quantile function [or inverse cumulative distribution function (CDF)] is a probabilistic measure that is widely employed in both statistical applications and Monte Carlo...     

In-Plane Magnetic Field-Driven Creation and Annihilation of Magnetic Skyrmion Strings in Nanostructures

In bulk chiral crystals, 3D structures of magnetic skyrmions form topologically protected skyrmion strings (SkS) that have shown potential as magnonic nano-waveguides for information transfer. Although SkS stability is expected to be enhanced in nanostructures of skyrmion-hosting materials, experimental observation and detection of SkS in nanostructures under an applied in-plane magnetic field is difficult. Here, temperature-dependent magnetic field-driven creation and annihilation of SkS in B20 FeGe nanostructures (nanowires and nanoplates) under in-plane magnetic field (H_||) are shown and the mechanisms behind these transformations are explained. Unusual asymmetric and hysteretic magnetoresistance (MR) features are observed but previously unexplained during magnetic phase transitions within the SkS stability regime when H_|| is along the nanostructure's long edge, which increase the sensitivity of MR detection. Lorentz transmission electron microscopy of the SkS and other magnetic textures under H_|| in corroboration with the analysis of the anisotropic MR responses elucidates the field-driven creation and annihilation processes of SkS responsible for such hysteretic MR features and reveals an unexplored stability regime in nanostructures.     

Tunable Néel–Bloch Magnetic Twists in Fe3GeTe2 with van der Waals Structure

The advent of ferromagnetism in 2D van der Waals (vdW) magnets has stimulated high interest in exploring topological magnetic textures, such as skyrmions for use in future skyrmion-based spintronic devices. To engineer skyrmions in vdW magnets by transforming Bloch-type magnetic bubbles into Néel-type skyrmions, a heavy metal/vdW magnetic thin film heterostructure has been made to induce interfacial Dzyaloshinskii–Moriya interaction (DMI). However, the unambiguous identification of the magnetic textures inherent to vdW magnets, for example, whether the magnetic twists (skyrmions/domain walls) are Néel- or Bloch-type, is unclear. Here we demonstrate that the magnetic twists can be tuned between Néel and Bloch-type in the vdW magnet Fe₃GeTe₂ (FGT) with/without interfacial DMI. We use an in-plane magnetic field to align the modulation wavevector q of the magnetizations in order to distinguish the Néel- or Bloch-type magnetic twists. We observe that q is perpendicular to the in-plane field in the heterostructure (Pt/oxidized-FGT/FGT/oxidized-FGT), while q aligns at a rotated angle with respect to the field direction in the FGT thin plate thinned from bulk. We find that the aligned domain wall twists hold fan-like modulations, coinciding qualitatively with our computational results.     

Applied whispering gallery modes on ZnO nanorods coated glass for humidity sensing application

In this letter, a humidity sensor is demonstrated by applying a whispering gallery mode (WGM) from a microsphere resonator onto the ZnO nanorods coated glass surface. The diameter of the microsphere was 234 µm and the glass surface was coated with ZnO nanorods using the hydrothermal method at growth duration of 12 h. A significant response to humidity level ranging from 35%RH to 85%RH has been observed with the sensitivity of 0.014 2 nm/%RH. The proposed humidity sensor has successfully employed to enhance interaction between the whispering gallery mode evanescent and surrounds analyte with the assistance of ZnO nanorods coated glass.     

Gold nanoparticles film for Q-switched pulse generation in thulium doped fiber laser cavity

Passively Q-switched thulium doped fiber laser (TDFL) has been successfully demonstrated using gold nanoparticles (GNPs), which were embedded into polyvinyl alcohol as saturable absorber (SA). The stable self-starting Q-switched laser was generated to operate at 1 891 nm when a tiny piece of the prepared film was slot in between two fiber ferrules and incorporated into the laser cavity. The repetition rate can be adjusted from 48.54 kHz to 49.64 kHz while the pulse width decreased from 3.52 μs to 2.38 μs with the increase of 1 550 nm pump power from 840 mW to 930 mW. The corresponding pump power output power linearly increased from 3.62 mW to 6.3 mW with a slope efficiency of 2.53%. The maximum peak power and pulse energy were recorded at about 39 mW and 0.12 µJ, respectively at pump power of 930 mW. The Q-switching operation was caused by the surface plasmon resonance absorption of GNPs.     

Augmented finite transition systems as abstractions for control synthesis

This work is motivated by the problem of synthesizing switching protocols for continuous switched systems described by differential or difference equations, in a way that guarantees that the resulting closed-loop trajectories satisfy certain high-level specifications expressed in linear temporal logic. We introduce augmented finite transition systems as an abstract representation of the continuous dynamics; the augmentation consists in encodings of liveness properties that can be used to enforce progress in accordance with the underlying continuous dynamics. Abstraction and refinement relations that induce a preorder on this class of finite transition systems are established, and, by construction, this preorder respects the feasibility (i.e., realizability) of the synthesis problem. Hence, existence of a discrete strategy for one of these abstract finite transition systems guarantees the existence of a switching protocol for the continuous system that enforces the specification for all resulting trajectories. We show how abstractions and refinements can be computed for different classes of continuous systems through an incremental synthesis procedure that starts with a coarse abstraction and gradually refines it according to the established preorder relations. Finally, the incremental synthesis procedure is tailored to a class of temporal logic formulas by utilizing specific fixed point structures to enable localized updates in the refinement steps. The procedure is not guaranteed to terminate in general but we illustrate its practical applicability on numerical examples.     

Quantification of silane grafting efficacy,weak IR vibration bands and percentage crystallinity in post e-beam irradiated UHMWPE

Vinyl-tri-methoxy silane (VTMS) and vinyl-tri-ethoxy silane (VTES) were grafted onto ultra-high molecular weight polyethylene (UHMWPE) by irradiating the UHMWPE/silane hybrids with e-beam. The samples were irradiated under high moisture contents for total dose values of 30, 65 and 100 kGy, respectively. The synergistic effect of silane and irradiation on the grafting efficacy, concentration of weak bonds like trans-vinylene (–CH=CH–) and vinyl (–CH=CH₂) and percentage values of crystallinity were studied using FTIR spectroscopy. For the estimation of grafting reactions efficiency, absorption due to characteristic infrared absorption bands of –Si–CH– in the region ~800 cm^?1 was monitored and found that grafting efficacy of VTMS on UHMWPE was higher as compared to VTES and increased with irradiation. The relative amounts of grafting extension (R) for 100 kGy irradiated UHMWPE/VTMS and UHMWPE/VTES hybrids were found to increase 20 and 15 %, respectively. The concentration of trans-vinylene in UHMWPE was found to increase from 0.015 to 0.035 mmol/l due to synergistic effects of silane and irradiation. Moreover, crystallinity of UHWMPE was found to decrease from 65 to 55 % due to the abovementioned synergistic effects which was also confirmed with DSC tests. Furthermore, oxidation index values were measured to confirm the efficacy of silane as free radical quencher via silane grafting extension reactions.