Search Results (26)

Background/Objectives: The International Dysphagia Diet Standardisation Initiative (IDDSI) introduced Level 1 (slightly thick) as a new intermediate consistency between thin liquid (Level 0) and mildly thick (Level 2). Although over-thickening is associated with reduced hydration and impaired medication absorption, the specific clinical utility of Level 1 has not been quantified. We aimed to determine the clinical benefit of Level 1 and identify the proportion of dysphagia patients for whom Level 1 is the minimum sufficient consistency. Methods: We retrospectively analyzed 163 consecutive patients undergoing a videofluoroscopic swallowing study (VFSS) in a single rehabilitation department, including a pre-specified stroke subgroup (n = 87). A de-escalation protocol was used (IDDSI Level 3 → 2 → 1 → 0) with stepwise bolus volumes (2–3 mL followed by 5 mL at each consistency), and testing was discontinued at thinner consistencies once aspiration (Penetration–Aspiration Scale [PAS] ≥ 6) was observed. PAS values at untested thinner levels following aspiration were imputed (assigned an assumed value reflecting the expected clinical outcome) as 8 in the primary analysis. We quantified Level 1 effectiveness using absolute risk reduction (ARR), relative risk reduction (RRR), and number needed to treat (NNT). Results: In paired analyses, Level 1 reduced aspiration versus Level 0 by 12.0 percentage points (RRR 31.5%, NNT 8.4) in the full cohort and 13.7 percentage points (RRR 38.5%, NNT 7.3) in the stroke subgroup. Incremental escalation from Level 1 to Level 2 yielded only modest additional benefit (incremental NNT 18.4 and 38.5). Patient-level classification identified 13.7% (full) and 16.5% (stroke) of patients as “Level 1-sufficient”, defined as unsafe on thin liquid but safe on Level 1. Conclusions: IDDSI Level 1 provides substantial aspiration protection compared to thin liquid (NNT ≈ 7–8) with diminishing returns from further escalation, supporting Level 1 as a clinically useful and underutilized first-line thickened liquid option that may help avoid the nutritional and hydration drawbacks of over-thickening. Full article

In this paper, we investigate the absolute stability of several Translationally Invariant Configurations (TICs) observed in cholesteric liquid crystal samples. The bounding plates of the samples may impose homeotropic anchoring (case 1), slightly tilted anchoring when the plates are also rubbed in either the same (case 2) or opposite (case 3) directions, or hybrid anchoring with planar on one plate and homeotropic on the other. In each case, the stability is examined as a function of the confinement ratio—defined as the ratio of the sample thickness to the cholesteric pitch—and of the applied field (electric and/or magnetic). Full article

The liquid spreading on structured packings plays an essential role in affecting gas–liquid mass transfer in separation columns, yet the synergistic mechanism of surface wettability and textured geometries remains insufficiently understood. This study integrates experimental and computational methods to systematically investigate the liquid spreading characteristics on textured surfaces. The synergistic combination of hydrophilic modification and surface textures markedly enhances liquid spreading performance. Compared with the hydrophilic plane surface, the spherical cap texture increases the interface area and wetted area by 25.2% and 49.6%, respectively, while the pyramid-shaped texture leads to improvements of 24.5% and 48.9%, respectively. Based on Weber number analysis, it is identified that the competition between inertial force and surface tension governs the evolution of liquid spreading regimes. In addition, the results suggest that variations in liquid viscosity and density may further influence spreading behavior by modifying the balance among inertial, viscous, and surface tension forces. The geometric parameters of spherical cap textures are systematically examined, and it is revealed that a spherical cap with a non-uniform staggered configuration (Mode III) enables the efficient liquid spreading. A new non-uniform spherical cap texture is designed to enhance liquid spreading, which enhances spreading performance compared with the original plate, increasing the interface area by 27.3% and the wetted area by 47.4%. Although the liquid film thickness increases slightly, the wetted area ratio is significantly improved, indicating enhanced effective surface coverage. Both simulations and experiments confirm that the new textured structure further enhances liquid spreading performance on the textured surface. This research unveils a strategy to improve liquid spreading through tailored surface textures, opening up new possibilities for the design of efficient packings. Full article

The efficiency of an electrolyzer is significantly influenced by mass, heat, and charge transport within its porous transport layer (PTL). The infeasibility of measuring them in-situ makes it challenging to study their influence experimentally, leading to the adoption of various modeling approaches. This study applies pore network (PN) modeling to investigate mass transport properties and capillary invasion behavior in three commercial titanium felt PTLs commonly used in proton exchange membrane water electrolyzers (PEMWEs). One PTL has a graded structure. Reconstructed PNs were derived from microcomputed X-ray tomography (µ-CT) data, allowing for a detailed analysis of pore size distributions, absolute and relative permeabilities, capillary pressure curves, and residual liquid saturations. The results from the PN approach are compared to literature correlations. The absolute permeability of all PTLs is between 1.1 × 10⁻¹⁰ m² and 1.5 × 10⁻¹⁰ m², with good agreement between PNM results and predictions from the Jackson and James model and the Tomadakis and Sotirchos model, the two latter involving the fiber diameter as a model parameter. The graded PTL, with fiber diameters varying between 25 µm and 40 µm, showed the best agreement with literature correlations. However, the capillary pressure curves exhibited significant deviations from the Leverett and Brooks–Corey equations at low and high liquid saturations, emphasizing the limitations of these correlations. In addition, residual liquid saturation varied strongly with PTL structure. The thicker PTL with a slightly narrower pore size distribution, demonstrated a lower residual liquid saturation (19%) and a more homogeneous invasion compared to the graded PTL (64%), which exhibited significant gas fingering. The results suggest that higher gas saturation could enhance gas removal, with much higher relative permeabilities, despite the greater PTL thickness. In contrast, the graded PTL achieves the highest relative liquid permeability (~70%) while maintaining a relative gas permeability of ~30%. These findings highlight the impact of microstructure on invasion and transport properties and suggest PN modeling as a powerful tool for their study. Full article

The utilization of liquid-cooled plates has been increasingly prevalent within the thermal management of batteries for new energy vehicles. Using Tesla valves as internal flow channels of liquid-cooled plates can improve heat dissipation characteristics. However, conventional Tesla valve flow channels frequently experience challenges such as inconsistencies in heat dissipations and unacceptably high levels of pressure loss. In light of this, this paper proposes a new type of Tesla valve with partitions, which is used as internal channel for liquid-cooled plate. Its purpose is to solve the shortcomings of existing flow channels. Under the working conditions of Reynolds number equal to 1000, the neural network prediction-NSGA-II multi-objective optimization method is used to optimize the channel structural parameters. The objective is to identify the optimal structural configuration that exhibits the greatest Nusselt number while simultaneously exhibiting the lowest Fanning friction factor. The variables to consider are the half of partition thickness H, partition length L, and the fillet radius R. The study result revealed that the optimal parameter combination consisted of H = 0.25 mm, R = 1.253 mm, L = 0.768 mm, which demonstrated the best performance. The Fanning friction factor of the optimized flow channel is substantially reduced compared to the reference channel, reducing by approximately 16.4%. However, the Nusselt number is not noticeably increased, increasing by only 0.9%. This indicates that the optimized structure can notably reduce the fluid’s friction resistance and pressure loss and slightly enhance the heat dissipation characteristics. Full article

In this paper, we demonstrate a novel photonic hook being initiated using an air–liquid interface (ALI). This bent light focus is produced by immersing a dielectric micro-cylinder partially at the edge of a thin liquid film whose thickness is smaller than the diameter of the micro-cylinder. Unlike the well-known properties of normal near-field focuses, this photonic hook propagates horizontally in the liquid along the ALI at specific depths and does not require the material processing of microscopic particles or the modulation of light irradiation for initiation. A morphological analysis indicates that the contrast in the refractive indexes of the ALI causes this phenomenon at the shadow end of the micro-cylinder with a transverse dimension smaller than the diffraction limit. Compared to previously discovered photonic hooks, the unique setup of this photonic hook can generate a force field that enables optical trapping in the region slightly beneath the ALI, and the related optical pressures have been simulated. Full article

In the continuous casting, the protective slag is coated on the surface of the molten steel, which is an important factor affecting the quality of the billet. The liquid slag layer on the surface of molten steel should be kept at an appropriate thickness to ensure a sufficient supply of liquid slag and to prevent slag from becoming entangled in the billet shell. Moreover, the consumption of protective slag should be appropriate to ensure stable liquid slag film thickness and uniform heat transfer between the casting billet and the mold. In this work, a two-dimensional numerical calculation model using volume of fluid method was established for the flow of protective slag, the Navier–Stokes equation was solved for the model, the consumption of protective slag during a vibration cycle was calculated, and the effects of factors such as casting speed, amplitude, and vibration frequency on the consumption of protective slag were explored. The results showed that when the casting speed increased from 1.2 m/min to 1.6 m/min, the consumption of protective slag per unit area decreased by about 4.76%, but the consumption of protective slag per unit length of the casting billet increased by about 26.98% within a vibration cycle. The consumption of protective slag per unit area and per unit billet length within a vibration cycle increased slightly with the increase of amplitude. The variation pattern of the consumption of protective slag with vibration frequency was not obvious. This model can provide theoretical basis and technical guidance for the design of protective slag, thereby improving the quality of steel billets in steel plants. Full article

Revealing the interface effect on lubrication is great significance for designing high performance water-based lubricating friction pairs. In this study, a new thin film lubrication numerical model considering the electrical double layer (EDL) effect with an imperfect coating in point contact is proposed, and the validity and effectiveness of the model is verified. The numerical results show that increasing the zeta potential increases the film thickness, which indicates that the EDL effect can improve the firm lubricated film formation. However, the effect of the zeta potential on the von Mises stress is very small because the liquid film pressure remains constant at different surface potentials. On the other hand, with an increase in coating thickness, the effects of the coating on the film thickness and pressure gradually become evident, but the von Mises stress is affected by the imperfectly bonded interface and coating thickness. Finally, the effect of surface roughness on thin film lubrication was analyzed. The liquid film thickness slightly decreased and the occurrence of stress concentration on the surface coating was evident. The proposed model was expected to provide a calculation basis for solving the thin film lubrication problem of coatings affected by the EDL. Full article

In this paper, we numerically and experimentally show that the director field orientation degeneracy within the Translationally Invariant Configuration (TIC) of a cholesteric liquid crystal under an electric field can be lifted by imposing a magnetic field $\overrightarrow{B}$ parallel to the electrodes. The configuration can be either parallel or perpendicular to the magnetic field depending on the values of the sample thickness, pitch, and applied voltage, with two equiprobable orientations in each case. The transition between the parallel and perpendicular orientations has hysteresis, suggesting that it is first order. When $\overrightarrow{B}$ is slightly tilted with respect to the electrode plane, the indeterminacy on the TIC orientation is removed when the TIC is directed along $\overrightarrow{B}$. Full article

Liquid rocket engines with hydrogen peroxide and kerosene have the advantages of high density specific impulse, high reliability, and no ignition system. At present, the cooling problem of hydrogen peroxide engines, especially with regenerative cooling, has been little explored. In this study, a realizable k-epsilon turbulence model, discrete phase model, eddy dissipation concept model, and 10-step 10-component reaction mechanism of kerosene with oxygen are used. The increased rib height of the regenerative cooling channel causes the inner wall temperature of the engine increases, the average temperature of the coolant outlet decreases slightly, and the coolant pressure decreases. The overall wall temperature decreases as the rib width of the regenerative cooling channel increases. However, in the nozzle throat area, the wall temperature increases, the average coolant outlet temperature decreases, and the coolant pressure drop increases. A decrease in the inner wall thickness of the regenerative cooling channel results in a significant decrease in the wall temperature and a small increase in the average coolant outlet temperature. These findings contribute to the further development of the engine with hydrogen peroxide and can guide the design of its regenerative cooling process. Full article

Due to the inability of conventional wastewater treatment procedures to remove organic pharmaceutical pollutants, active pharmaceutical components remain in wastewater and even reach tap water. In terms of pharmaceutical pollutants, the scientific community focuses on β-blockers due to their extensive (over)usage and moderately high solubility. In this study, the photocatalytic activity of V₂O₅ was investigated through the degradation of nadolol (NAD), pindolol (PIN), metoprolol (MET), and their mixture under ultraviolet (UV) irradiation in water. For the preparation of V₂O₅, facile hydrothermal synthesis was used. The structural, morphological, and surface properties and purity of synthesized V₂O₅ powder were investigated by scanning electron microscopy (SEM), X-ray, and Raman spectroscopy. SEM micrographs showed hexagonal-shaped platelets with well-defined morphology of materials with diameters in the range of 10–65 µm and thickness of around a few microns. X-ray diffraction identified only one crystalline phase in the sample. The Raman scattering measurements taken on the catalyst confirmed the result of XRPD. Degradation kinetics were monitored by ultra-fast liquid chromatography with diode array detection. The results showed that in individual solutions, photocatalytic degradation of MET and NAD was relatively insignificant (<10%). However, in the PIN case, the degradation was significant (64%). In the mixture, the photodegradation efficiency of MET and NAD slightly increased (15% and 13%). Conversely, it reduced the PIN to the still satisfactory value of 40%. Computational analysis based on molecular and periodic density functional theory calculations was used to complement our experimental findings. Calculations of the average local ionization energy indicate that the PIN is the most reactive of all three considered molecules in terms of removing an electron from it. Full article

Compound events occur when multiple drivers or hazards occur in the same region or on the same time scale, hence amplifying their impacts. Compound events can cause large economic damage or endanger human lives. Thus, a better understanding of the characteristics of these events is needed in order to protect human lives. This study investigates the drivers and characteristics of floods in Europe and North America from the compound event perspective. More than 100 catchments across Europe and North America were selected as case study examples in order to investigate characteristics of floods during a 1979–2019 period. Air temperature, precipitation, snow thickness, snow liquid water equivalent, wind speed, vapour pressure, and soil moisture content were used as potential drivers. Annual maximum floods were classified into several flood types. Predefined flood types were snowmelt floods, rain-on-snow floods, short precipitation floods and long precipitation floods that were further classified into two sub-categories (i.e., wet and dry initial conditions). The results of this study show that snowmelt floods were often the dominant flood type in the selected catchments, especially at higher latitudes. Moreover, snow-related floods were slightly less frequent for high altitude catchments compared to low- and medium-elevation catchments. These high-altitude areas often experience intense summer rainstorms that generate the highest annual discharges. On the other hand, snowmelt-driven floods were the predominant flood type for the lower elevation catchments. Moreover, wet initial conditions were more frequent than the dry initial conditions, indicating the importance of the soil moisture for flood generation. Hence, these findings can be used for flood risk management and modelling. Full article

Molecular dynamics simulations of ultrathin free-standing layers made of melted (373.15–673.15 K) polyethylene chains, which exhibit a lower melting temperature (compared to the bulk value), were carried out to investigate the dominant pressure forces that shape the conformation of chains at the interfacial and bulk liquid regions. We investigated layer thicknesses, $t_L$, from the critical limit of mechanical stability up to lengths of tens of nm and found a normal distribution of bonds dominated by slightly stretched chains across the entire layer, even at large temperatures. In the bulk region, the contribution of bond vibrations to pressure was one order of magnitude larger than the contributions from interchain interactions, which changed from cohesive to noncohesive at larger temperatures just at a transition temperature that was found to be close to the experimentally derived onset temperature for thermal stability. The interchain interactions produced noncohesive interfacial regions at all temperatures in both directions (normal and lateral to the surface layer). Predictions for the value of the surface tension, $\gamma$, were consistent with experimental results and were independent of $t_L$. However, the real interfacial thickness—measured from the outermost part of the interface up to the point where $\gamma$ reached its maximum value—was found to be dependent on $t_L$, located at a distance of 62 Å from the Gibbs dividing surface in the largest layer studied (1568 chains or 313,600 bins); this was ~4 times the length of the interfacial thickness measured in the density profiles. Full article

The properties of GaAsSbN and GaAsSb layers grown by liquid-phase epitaxy on n-GaAs substrates were investigated in a comparative plan with a view of their possible application in multi-junction solar cells. To avoid non-uniformity effects in the composition of these compounds with two or three different group-V volatile elements, the crystallization was carried out from finite melt with a thickness of 0.5 mm at low (<560 °C) temperatures. X-ray microanalysis and X-ray diffraction were used to determine the composition, lattice mismatch, and crystalline quality of the epitaxial layers. The morphology and surface roughness were examined by atomic force microscopy. Surface photovoltage (SPV) spectroscopy at room temperature was applied to study the optical absorption properties and the photocarrier transport in the samples. The long-wavelength photosensitivity of the GaAsSbN and GaAsSb layers, determined from their SPV spectra, is extended down to 1.2 eV. Although GaAsSb has a slightly larger lattice mismatch with the GaAs substrate compared to GaAsSbN, it presents a higher photoresponse, since, in GaAsSbN, the incorporation of N induces additional recombination centres. Therefore, GaAsSb could be an alternative to GaAsSbN for solar cell applications. Full article

Meteorological variables (e.g., air temperature (T2), radiation flux, and precipitation) determine the evolution of glacier mass and characteristics. Observations of these variables are not available with adequate spatial coverage and spatiotemporal resolution over the Tibetan Plateau. Albedo is the key factor of net radiation and is determined by the land cover and snow-related variables. This study focuses on evaluating the performance of the albedo parameterization scheme in WRF coupled with Noah-MP in terms of glacio-meteorological variables, by conducting experiments applying the standard surface albedo scheme with the default vegetation and corrected to ice cover and the modified glacial albedo scheme to the Parlung No. 4 Glacier in the 2016 ablation season. In situ glacio-meteorological element observations and MODIS-retrieved albedo are selected to assess the performance of the model. The key results are as follows. First, compared to the air temperature bias of 1.56 °C in WRF applying the standard surface albedo scheme and the default vegetation cover, realistic land-use categories considerably reduce the model warm bias on the glacier. The model using realistic land-use categories yields similar T2 diurnal patterns to the observations, with a mean bias of only −0.5 °C, no matter which glacial albedo scheme is implemented. Second, the default glacial albedo scheme gives a rather high albedo value of 0.68, causing an apparent underestimation of the net shortwave radiation and net radiation; the modified glacial albedo scheme gives a mean albedo value of 0.35, close to the in situ observations, helping to relieve underestimations of net shortwave radiation and net radiation. Compared with the MODIS albedo of the glacier, WRF applying the default glacial albedo scheme apparently overestimates the albedo with a mean error of 0.18, while WRF applying the modified glacial albedo scheme slightly underestimates the albedo with a mean error of only −0.08. Third, the mean net radiation flux (142 W m⁻²) and high ground heat flux (182 W m⁻²) values that were estimated by WRF applying the corrected land cover and the modified glacial albedo scheme result in the heating of the glacier surface and subsurface, causing ice melt and the liquid water content to increase more quickly and preferentially, equating to an estimated ice thickness decrease of 1 m by mid-June in the ablation region. Our study confirms the ability of the WRF model to reproduce glacio-meteorological variables as long as a reasonable glacial albedo scheme and the corrected land cover is applied and provides a theoretical reference for researchers that are committed to further improvement of the glacial albedo scheme. Full article