The fifth-order accurate Weighted Essentially Nonoscillatory space discretization developed by Jiang and Shu (WENO-JS) is studied theoretically. An exact Nonlinear Spectral Method (NSM) is developed ...based on an innovative yet simple methodology. The NSM explains the behaviour of nonsmooth solutions because it is valid for arbitrary modified wave numbers (MWN). The NSM clarifies the effects of the time integration methods and the Courant number. The mode isolation assumption, extensively used to analyse WENO-JS, is elucidated, and several novel findings are presented. The improved performance of the combination of WENO-JS with the forward Euler time integration method, compared to the Linear Fifth-Order Upwind discretization, is illustrated. The overdamping of the combination of WENO-JS with the popular third-order total variation diminishing Runge-Kutta method is discovered. Thus, the NSM covers several gaps in the current literature.
Understanding the salt tolerance mechanism in obligate halophytes provides valuable information for conservation and re-habitation of saline areas. Here, we investigated the responses of three ...obligate halophytes namely Arthrocnemum macrostachyum, Sarcocornia fruticosa and Salicornia europaea to salt stress (0, 100, 200, 400 and 600 mM NaCl) during their vegetative growth with regard to biomass, ions contents (Na+, K+ and Ca2+), chlorophyll contents, carotenoids, phenolic compounds, flavonoids, and superoxide dismutase, peroxidase and esterase activities. S. europaea showed the lowest biomass, root K+ content, Chl a/b ratio, and carotenoids under salinity. This reduction of biomass is concomitant with the increase in proline contents and peroxidase activity. On the other hand, the promotion of growth under low salinity and maintenance under high salinity (200 and 400 Mm NaCl) in A. Macrostachyum and S. fruticosa are accompanied by an increase in Chl a/b ratio, carotenoids, phenolics contents, and esterase activity. Proline content was decreased under high salinity (400 and 600 mM NaCl) in both species compared to S. europaea, while peroxidase showed the lowest activity in both plants under all salt levels except under 600 mM NaCl in Arthrocnemum macrostachyum compared to S. europaea. These results suggest two differential strategies; (1) the salt tolerance is due to activation of antioxidant enzymes and biosynthesis of proline in S. europaea, (2) the salt tolerance in A. macrostachyum, S. fruticosa are due to rearrangement of chlorophyll ratio and biosynthesis of antioxidant compounds (carotenoids, phenolics and flavonoids) which their cost seem to need less energy than activation of antioxidant enzymes. The differential behavior in halophytes of the same habitat confirms that the tolerance mechanism in halophytes is species-specific which provides new insight about the restoration strategy of saline areas.
With the growing deployment of microgrids, it has become urgent to investigate the microgrid behavior during transient faults and subsequent islanding conditions. The load type and the manner in ...which distributed generations (DGs) are controlled can have substantial impacts on the dynamic performance of microgrids. In this paper, impacts of different control schemes of the inverter-based DG and microgrid load types on the microgrid stability subsequent to fault-forced islanding are investigated. A microgrid model, simulated on Matlab/Simulink software, is analyzed including a mix of synchronous and inverter-based DG and a combination of passive RLC and induction motor (IM) loads. Simulation results show that in the presence of IM loads, the microgrid may lose its stable operation even if the fault is isolated within a typical clearing time. The critical clearing time of a microgrid is highly dependent on the microgrid control strategy, DG interface control, and load type. Induction motor loads can prove problematical to microgrid transient stability, particularly in situations in which the voltage dip can cause the induction motor to "pull out".
We investigate the collider signatures of neutral and charged long-lived particles (LLPs), predicted by the supersymmetric B−L extension of the Standard Model (BLSSM), at the Large Hadron Collider ...(LHC). The BLSSM is a natural extension of the minimal supersymmetric Standard Model (MSSM) that can account for nonvanishing neutrino masses. We show that the lightest right-handed sneutrino can be the lightest supersymmetric particle (LSP), while the next-to-the LSP (NLSP) is either the lightest left-handed sneutrino or the left-handed stau, which are natural candidates for the LLPs. We analyze the displaced vertex signature of the neutral LLP (the lightest left-handed sneutrino) and the charged tracks associated with the charged LLP (the left-handed stau). We show that the production cross sections of our neutral and charged LLPs are relatively large, namely of order O(1) fb. Thus, probing these particles at the LHC is quite plausible. In addition, we find that the displaced dilepton associated with the lightest left-handed sneutrino has a large impact parameter that discriminates it from other SM leptons. We also emphasize that the charged track associated with the left-handed stau has a large momentum with slow moving charged tracks, hence it is distinguished from the SM background, and therefore it can be accessible at the LHC.
Abstract The pure conjugated polyarylene azomethine (CPAA) and its nanocomposites (CPAA-TiO 2 ) with different concentrations of TiO 2 nanoparticles were successfully prepared by in-situ technique ...and analyzed by different advanced techniques. XRD has confirmed the structural properties and crystallinity of (CPAA) and nanocomposites. The SEM clearly shows that the (CPAA) is uniform and homogeneous, with tightly connected aggregate layers in shape. However, the amount of TiO 2 in the nanocomposites greatly affects their morphology, revealing structural differences and indicating a reaction between (CPAA) and TiO 2 , especially at a higher concentration of 5% TiO 2 . A new composite of (CPAA) was introduced and the photocatalytic effect for MB was studied. The removal efficiency of (pure-CPAA) over MB dye under simulated sunlight was 62%. However, (CPAA-TiO 2 1%) destroyed 90% of MB dyes. It was discovered that the low band gap of (CPAA-TiO 2 1% (2.84 eV)) accelerates high electron–hole recombination, increasing photocatalytic activity.
Polyaniline/SiO2 composite was successfully prepared via in situ polymerization using polyvinyl alcohol as a surfactant. The prepared PAn/SiO2 composite was used for the removal of Zr(IV), U(VI), and ...Mo(VI) ions from their liquid solutions. PAn/SiO2 composite was characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The synthesized composite was irradiated with γ-radiation from a Co-60 radioactive source with absorbed dose 50, 100, and 150 kGy and the corresponding changes in structural properties of the composites were studied. The thermal and radiation stabilities of PAn/SiO2 composite in terms of saturation capacities were studied. PAn/SiO2 composite has a good thermal stability as it retained about 78.83% of its saturation capacity upon heating at 400±1 °C, while the saturation capacity of PAn/SiO2 composite was increased from 191.28 to 319.16 mg/g for Zr(IV) with varying the irradiated doses from 0 to 150 kGy. The sorption studies for several metal ions revealed marked selectivity of PAn/SiO2 composite towards Zr(IV), U(VI), and Mo(VI) ions with selectivity order; Zr(IV) > U(VI) > Mo(VI). The results indicated that PAn/SiO2 composite removed 95.33, 75.97, and 52.87% from Zr(IV), U(VI), and Mo(VI) ions, respectively at pH 3.26. Hence, analytical utility of PAn/SiO2 composite was accomplished by performing some quantitative separation such as separation of U(VI) ions from monazite leachate and separation of Zr(IV), U(VI), and Mo(VI) ions from simulated liquid waste. Thermodynamic parameter studies concluded that the adsorption of Zr(IV), U(VI), and Mo(VI) ions was spontaneous and endothermic in nature.
•Isolation of silica from rice straw.•Binding of isolated silica with polyaniline.•Characterization of PAn/SiO2 composite.•Selective removal of U(VI) species from low grade monazite leachate.•Recovery of Zr(IV), U(VI), and Mo(VI) ions from simulated liquid waste.
Keeping the generators operating during transient grid faults becomes an obligation for the bulk wind generation units connected to the transmission network, and it is highly desired for distribution ...wind generators. A proposed scheme is implemented to keep the wind-power DFIG operating during transient grid faults. Challenges imposed on the generator configuration and the control during the fault and recovering periods are presented. A comprehensive time domain model for the DFIG with the decoupled dq controller is implemented using Matlab/Simulink software. Intensive simulation results are discussed to ensure the validity and feasibility of the proposed fault ride through technique. The scheme protects the DFIG components, fulfills the grid code requirements and optimises the hardware added to the generator.
Transverse thoracic block is a new perioperative analgesic method for post-sternotomy discomfort. This study discusses the efficacy of an ultrasound-guided transversus thoracic muscle plane block ...(TTPB) in patients undergoing heart surgery, including sternotomy.
In this prospective trial, 60 patients were randomly assigned to two groups: transversus (T) or general anesthesia (GA). Patients in the T group received TTPB with GA and 15 mL of 0.25% bupivacaine was administered on either side. Patients in the GA group received TTPB along with GA, but 15 mL saline was injected on either side instead. The patients were followed up postoperatively. The percentage of patients receiving additional opioids, extubation time, intensive care unit (ICU) length, postoperative morphine dose, and adverse events were documented.
The percentage of patients requiring additional morphine was significantly lower in the T group (p<0.015). Pain scores were comparable between the groups at extubation time and 18 h postoperatively. At 8, 12, and 24 h after surgery, pain scores in the T group were significantly lower (P<0.001). The total amount of morphine required after surgery was much lower in the T group (8±0.74 mg), and the duration to initial analgesic necessity was significantly greater in the GA group (P<0.001). Patients in the GA group had a considerably longer ventilation time (11.07±0.64) (P<0.001). The ICU stay in the T group was substantially shorter (P<0.001), and postoperative complications were comparable.
For patients undergoing heart surgery, TTPB offers sufficient postoperative pain control, resulting in lower pain scores, lower postoperative analgesic doses, shorter extubation times, and shorter ICU stay lengths.
Polytrauma patients are at a higher risk of delayed gastric emptying. To assess the gastric volume, a reliable diagnostic tool is needed to prevent the occurrence of aspiration pneumonia, which ...remains a serious complication associated with anesthesia. Gastric antral ultrasound can provide reliable information about the size of the gastric antrum in traumatized patients undergoing emergency surgery.
A prospective observational study of 45 polytrauma patients undergoing emergency surgery under general anesthesia was carried out. Prior to induction of anesthesia in the emergency department, gastric ultrasound was performed for qualitative and quantitative assessment of the gastric antrum in a supine position and right lateral decubitus (RLD) position. This was followed by routine placement of the nasogastric tube to aspirate and calculate the volume of the stomach contents.
Of the 45 polytrauma patients, the risk assessment of aspiration and the anesthesia technique changed in 14 patients (31.1%) after the gastric ultrasound examination. A very good relationship existed between the expected stomach volume at the RLD position and the suction volume in the nasogastric tube. In all cases, no aspirations were documented.
Ultrasound examination of the stomach in polytrauma patients allows assessing the size and type of stomach contents. The data obtained can influence the choice of anesthesia technique and reduce the risk of aspiration pneumonia.
This trial was registered at ClinicalTrials.gov . registry number: NCT04083677 on September 6, 2019.
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