Depth Of Trough Research Articles

Experimental Study of Bedform Development Characteristics and Their Effects on Sediment Transport

Bedforms are complex and varied features on riverbeds created by the interaction between flow and sediment particles. Bedform evolution is crucial for understanding sediment transport, bed resistance, and the ecological environment of rivers. In this study, a series of movable-bed dune experiments were conducted utilizing advanced 3D topographic laser scanning technology to precisely measure the 2D and 3D dune bedforms under various conditions. This enabled the detailed analysis of the bedform parameters, including the dune length and height, the crest height, and the trough depth. Furthermore, this study examined the relationship between bed resistance and dune morphology and investigated how the intensity of bedload transport affects bed resistance. The findings indicate that bedload mass transport on the riverbed significantly contributes to increased bed resistance. Given the limitations of the traditional bedload transport rate formulas for dune bedforms, this research introduces a new formula derived from the experimental data. The accuracy of this formula was confirmed using the nonlinear least squares method. Our study enhances the accuracy of sediment transport predictions and provides scientific support for river management and engineering practices.

Bridging the Gap Rather Than Filling the Entire Valley-Anatomic Insights When Treating the Medial Infraorbital Region.

The treatment of the medial infraorbital region also termed the tear trough has become increasingly popular by the use of soft tissue fillers in a minimally invasive approach using a cannula. A total of 246 tear troughs were injected and investigated originating from 123 study participants. The clinical outcome was evaluated 6 months after the treatment by independent observers based on standardized frontal images and the procedure was documented by ultrasound imaging. On average, 0.26 (0.1) cc [range: 0.08-0.32] of soft tissue filler material was injected per tear trough. Tear trough depth was before the treatment rated as 2.12 (0.4), whereas after the treatment it was 1.15 (0.4) (p < 0.001). Hyperpigmentation score was 2.19 (0.4) before the treatment, whereas after the treatment it was 1.31 (0.5) (p < 0.001). Intraorbital fat pseudo-prolapse severity was rated before the treatment 1.88 (0.7), whereas it was rated after the treatment 1.14 (0.3) (p < 0.001). Wrinkle severity of the lower eyelid was rated before the treatment 1.51 (0.6), whereas it was rated after the treatment 1.12 (0.3) (p < 0.001). The results of this retrospectively investigated case series revealed that the conducted injection technique for treating the tear trough for medial infraorbital hollowing with a cannula provided statistically significant clinical improvement with a limited adverse events profile. The technique utilized an injection approach which was perpendicularly oriented to the longitudinal axis of the tear trough thereby "bridging the gap instead of filling the entire valley."

Poster 254: Improvements in Kujala at Minimum Two-Years Following Medial Patellofemoral Ligament Reconstruction are Correlated with Intraoperative Instability Measurements: A Multivariate Analysis of Risk Factors

Objectives: Isolated medial patellofemoral ligament reconstruction (MPFLR) is an effective treatment for those suffering from patellofemoral instability. Currently, many concomitant procedures are associated with MPFLR that address underlying pathologic anatomy. The indication and need for such procedures are currently not well understood and often involve the use of more invasive techniques. We aim to identify patients who may be more vulnerable to worse outcomes. The purpose of this study is to correlate demographic, anatomical, and clinical risk factors to minimum two-year outcomes following isolated MPFLR. Methods: A retrospective review of patients undergoing isolated MPFLR for recurrent patellar instability at a single institution between December 2015-June 2021 was performed. Patients with concomitant osseous procedures beyond chondroplasty and any ligamentous procedure were excluded. Included patients completed patient reported outcome (PRO) surveys preoperatively then at a minimum of 2 years postoperatively. Demographic, radiographic, surgical, and clinical data was collected. Univariate correlations to minimum 2-year delta-PRO scores were calculated, then those reaching significance were included in a multivariable linear regression analysis. Results: One hundred and thirteen MPFLR patients were included (77 female, 36 male; age: 21.6 ± 9.1 years). Final Kujala score was 88.44 ± 14.12 at 2.97 ± 1.11 years postoperatively. On univariate testing, final Kujala score was significantly correlated with age at time of surgery ( P=0.035; r=0.218), body mass index (P=0.035; r=-0.204), and the degree of knee flexion at which the patella can no longer be manually dislocated laterally during an examination under anesthesia (Instability Resolution Angle — IRA; P=0.010; r=-0.318). The delta final Kujala score (mean score 30.72 ± 19.68) was significantly correlated with age at time of surgery (P=0.032; r=-0.207), age at time of first patellar instability event (P=0.001; r=0.364), Caton-Deschamps Index (CDI; P=0.026; r=-0.235), trochlear width (P=0.016; r=0.251), the percentage of trochlear-patellar overlap on sagittal MRI (P=0.031; r=0.227), and the depth of the central trochlear trough from the lateral trochlear peak (P=0.035; r=0.221)(Table 1). On multivariable linear regression analysis, a larger IRA remained significantly correlated with worse final Kujala scores ( P= 0.018) and delta final Kujala ( P= 0.04). Conclusions: A larger IRA on examination under anesthesia is independently correlated with worse final and delta final Kujala scores at a minimum of two-years after isolated MPFLR. This finding can help guide surgeons in their decision to do an isolated MPFLR or add in larger, more invasive procedures that address underlying anatomic pathologies.

Prolonged Lifespan of Superhydrophobic Thin Films and Coatings Using Recycled Polyethylene.

High-density polyethylene (HDPE) waste poses a significant environmental challenge due to its non-biodegradable nature and the vast quantities generated annually. However, conventional recycling methods are energy-intensive and often yield low-quality products. Herein, HDPE waste is upcycled into anti-aging, superhydrophobic thin films suitable for outdoor applications. A two-layer spin-casting method combined with heating-induced crosslinking is utilized to produce an exceptionally rough superhydrophobic surface, featuring a root mean square (RMS) roughness of 50 nm, an average crest height of 222 nm, an average trough depth of -264 nm, and a contact angle (CA) of 148°. To assess durability, weathering tests were conducted, revealing the films' susceptibility to degradation under harsh conditions. The films' resistance to environmental factors is improved by incorporating a UV absorber, maintaining their hydrophobic properties and mechanical strength. Our research demonstrates a sustainable method for upcycling waste into high-performance, weather-resistant, superhydrophobic films.

Shear Trough Depth and Geometry Relation Determined from Satellite Radar Images from One or Two Orbits

Shear Trough Depth and Geometry Relation Determined from Satellite Radar Images from One or Two Orbits

An investigation into the constitutive relation of corrugated metro rail material based on nano-indentation experiment and inverse analysis

To establish the constitutive relation of corrugated rail material, rail corrugation was reproduced. The material mechanical properties of corrugation peaks and troughs were obtained by experiment. A set of dimensionless functions was proposed for the elastic modulus, hardness and yield stress at arbitrary depth of corrugation peaks and troughs. By combining the finite element model and dimensional functions, the constitutive relations were obtained at different vertical and lateral positions of corrugation. The closer the material is to the rail surface, the larger the mechanical property values. The elastic modulus and hardness of corrugated rail material at the trough surface are higher than those at the peak, while the yield stress at the peak surface is higher than the trough.

Ground subsidence and polygon development due to thermokarst in the Lena-Aldan interfluve, eastern Siberia, revealed by satellite remote sensing data

Thermokarst development is a topographic change in the landscape that is commonly associated with permafrost degradation in ice-rich permafrost regions. The Lena-Aldan interfluvial area in Central Yakutia in eastern Siberia has undergone extensive thermokarst development in the last three decades, particularly in the vicinity of settlements. Despite the negative effects of thermokarst development on the inhabitants of these settlements, no quantitative observation methods have been developed to investigate the surface displacement due to thermokarst development over entire towns. This study utilized interferometric synthetic aperture radar to reveal ground-surface displacement associated with thermokarst near the settlements of selected towns. The findings showed that significant subsidence was detected in disturbed areas (farming and abundant arable land) near the towns. The magnitude of subsidence in the Tyungyulyu and Mayya areas was less than that in Churapcha and Amga. Polygon density in a defined area in each town was examined using high-resolution optical images. The polygon density in Churapcha was considerably lower than that in Mayya, whereas polygonal texture in some areas in Tyungyulyu and Amga was unclear. Spatial frequency analysis using satellite optical images showed clear differences in averaged spectrum models between well-developed and less-developed polygons, which may reflect trough depths and density of vegetation between polygons. Satellite-based subsidence maps and statistics describing polygon development may be useful for evaluating both initial and subsequent stages of thermokarst development.

Experimental Analysis of the Changes in Coral Sand Beach Profiles under Regular Wave Conditions

This study utilized 50 laboratory experiments to document the evolution of coral beaches under varying regular wave conditions, including five distinct wave periods and ten wave heights. Both the type of equilibrium beach and the shape of sand bars were used to represent beach evolution. The evolution of coral sand beaches was then compared to quartz sand beaches. The experimental results show that the predicted (modeled) equilibrium profile of a quartz sand beach was not applicable to coral sand beaches. Compared to sand bars on quartz sand beaches, the distance from bar crests to the beach berm in coral sand beaches was greater, whereas the erosional depth of sand troughs was deeper. However, the grain size distribution of sand associated with the coral sand beach under wave action was consistent with Celikoglu’s law. Both an equilibrium beach profile classification model and a sand bar shape prediction model for coral sand beaches were developed based on the experimental data.

Temperature evolution of pseudo magnetic properties and vortex state in Fe71Ga29 thin films

We report on the temperature evolution of pseudo magnetic properties and vortex state in Fe71Ga29 thin films at different substrate temperatures (RT-25 °C, 50 °C, 75 °C, and 150 °C) using minor loop analysis and first-order reversal curves respectively. Phase purity of Fe71Ga29 thin films confirmed with grazing incidence X–ray diffraction, which confirms the A2-type disordered phase. The minor loop parameters such as energy loss coefficient WF0 (362 kOe.emu/cc to 278 kOe.emu/cc) and trough depth coefficient WR0 (67.30 kOe.emu/cc to 50.23 kOe.emu/cc) values drop as grain size increases due to a reduction in defects as a result of an increase in substrate temperature. First-order reversal curves allow us to estimate the coercivity variation and switching field distribution that allow us to get information about magnetic interactions between the domains. Additionally, the contour plots of FORC and MFM phase images infer the coexistence of multidomain and Vortex State (VS) in all the Fe71Ga29 thin films deposited at different substrate temperatures.

The Circumgalactic Medium of Extreme Emission Line Galaxies at z∼2: Resolved Spectroscopy and Radiative Transfer Modeling of Spatially Extended Lyα Emission in the KBSS-KCWI Survey* *Based on data obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA, and was made possible by the generous

The resonantly scattered Lyα line illuminates the extended halos of neutral hydrogen in the circumgalactic medium of galaxies. We present integral field Keck Cosmic Web Imager observations of double-peaked, spatially extended Lyα emission in 12 relatively low-mass (M ⋆ ∼ 109 M⊙) z ∼ 2 galaxies characterized by extreme nebular emission lines. Using individual spaxels and small bins as well as radially binned profiles of larger regions, we find that for most objects in the sample the Lyα blue-to-red peak ratio increases, the peak separation decreases, and the fraction of flux emerging at line center increases with radius. We use new radiative transfer simulations to model each galaxy with a clumpy, multiphase outflow with radially varying outflow velocity, and self-consistently apply the same velocity model to the low-ionization interstellar absorption lines. These models reproduce the trends of peak ratio, peak separation, and trough depth with radius, and broadly reconcile outflow velocities inferred from Lyα and absorption lines. The galaxies in our sample are well-described by a model in which neutral, outflowing clumps are embedded in a hotter, more highly ionized inter-clump medium (ICM), whose residual neutral content produces absorption at the systemic redshift. The peak ratio, peak separation, and trough flux fraction are primarily governed by the line-of-sight component of the outflow velocity, the H i column density, and the residual neutral density in the ICM respectively. The azimuthal asymmetries in the line profile further suggest nonradial gas motions at large radii and variations in the H i column density in the outer halos.

Cosmic radio background from primordial black holes at cosmic dawn

The presence of an extra radio background besides the cosmic microwave background has important implications for the observation of the 21-cm signal during the cosmic Dark Ages, Cosmic Dawn, and epoch of Reionization. The strong absorption trough found in the 21-cm global spectrum measured by the EDGES experiment, which has a much greater depth than the standard model prediction, has drawn great interest to this scenario, but more generally it is still of great interest to consider such a cosmic radio background (CRB) in the early Universe. To be effective in affecting the 21-cm signal at early time, such a radio background must be produced by sources which can emit strong radio signals but modest amount of X-rays, so that the gas is not heated up too early. We investigate the scenario that such a radio background is produced by the primordial black holes (PBHs). For PBH with a single mass, we find that if the PBHs' abundance $\log(f_{\rm PBH})$ (ratio of total PBH mass density to total matter density) and mass satisfy the relation $\log(f_{\rm PBH}) \sim -1.8\log(M_\bullet/{\rm M}_{\odot})-3.5$ for $1\,{\rm M}_\odot \lesssim M_\bullet \lesssim 300 {\rm M}_\odot$, and have jet emission, they can generate a CRB required for reproducing the 21-cm absorption signal seen by the EDGES. The accretion rate can be boosted if the PBHs are surrounded by dark matter halos, which permits lower $f_{\rm PBH}$ value to satisfy the EDGES observation. In the latter scenario, since the accretion rate can evolve rapidly during the Cosmic Dawn, the frequency (redshift) and depth of the absorption trough can determine the mass and abundance of the PBHs simultaneously. For absorption trough redshift $\sim$ 17 and depth $\sim -500$ mK, it corresponds to $M_\bullet \sim 1.05\,{\rm M}_{\odot}$ and $f_{\rm PBH}\sim 1.5\times10^{-4}$.

The roles of climate and alternative prey in explaining 142 years of declining willow ptarmigan hunting yield

Long time series are important because they extend back to an era when animal populations were less influenced by habitat loss and climate change. Annual fluctuations in harvest yields are good proxies for large changes in population size and may reveal underlying ecological processes. From a variety of sources, we built a 142‐year long time series representing the mean daily catch (CPUE) of willow ptarmigan Lagopus lagopus in southeastern Norway. CPUE decreased over the 142 years, from approximately 35 birds shot per day in early years to around two in the last years. There were three periods in the time series: a first period with 3–5 year cycles of high peaks and low troughs (1872–1900), a short second period with similarly high peaks, variable depth of troughs and variable cyclicity (1901–1916), and a third long period with much lower peaks and faded cycles (1917–2013). Yearly variation in CPUE was best explained by an interacting effect of small rodent peak years and period, with a reduced positive effect of rodents in the last period, and a positive effect of the North Atlantic Oscillation index in spring and early summer. None of the weather variables with significant time trends explained any variation in CPUE and we could therefore not attribute the decline in CPUE directly to climate change. We postulate that a long‐term dampening of the amplitude in small rodent cycles combined with an increase in red fox numbers, have increased predation on alternative prey like ptarmigan, and prevented the populations from reaching their earlier peaks. Even though the present population of willow ptarmigan is only a fraction of what it was in former days, we recommend light hunting to motivate for monitoring and to keep public attention on the bird.

The Influence of Transport Stage on Preserved Fluvial Cross Strata

AbstractFluvial cross strata are depositional products of bedform migration that record formative flow and sediment transport conditions on planetary bodies. Bedform evolution varies with transport stage even under constant flow depths, but our understanding of how prevailing sediment transport conditions affect preserved cross strata is limited. Here, we analyzed experimental bedform evolution and preserved set thickness spanning threshold‐of‐motion to suspension‐dominated transport conditions at multiple equilibrium flow depths. Results show that bedform trough depth and mean preserved set thickness have a parabolic dependence on transport stage, with maximum values observed at intermediate transport stages. Our results indicate that transport stage is a key control on the flow‐depth‐normalized set thickness but set thickness is a poor indicator of flow depth. Thus, the dependence of bedform dimensions on transport stage should be considered in paleohydraulic reconstruction, and the analysis of set thickness may aid in the estimation of ancient fluvial sediment flux.

A correlation between H α trough depth and inclination in quiescent X-ray transients: evidence for a low-mass black hole in GRO J0422+32

ABSTRACT We present a new method to derive binary inclinations in quiescent black hole (BH) X-ray transients (XRTs), based on the depth of the trough (T) from double-peaked H α emission profiles arising in accretion discs. We find that the inclination angle (i) is linearly correlated with T in phase-averaged spectra with sufficient orbital coverage (≳50 per cent) and spectral resolution, following i(deg) = 93.5 × T + 23.7. The correlation is caused by a combination of line opacity and local broadening, where a leading (excess broadening) component scales with the deprojected velocity of the outer disc. Interestingly, such scaling allows to estimate the fundamental ratio M1/Porb by simply resolving the intrinsic width of the double-peak profile. We apply the T–i correlation to derive binary inclinations for GRO J0422+32 and Swift J1357−0933, two BH XRTs where strong flickering activity has hindered determining their values through ellipsoidal fits to photometric light curves. Remarkably, the inclination derived for GRO J0422+32 (i = 55.6 ± 4.1○) implies a BH mass of $2.7^{+0.7}_{-0.5}$ M⊙ thus placing it within the gap that separates BHs from neutron stars. This result proves that low-mass BHs exist in nature and strongly suggests that the so-called ‘mass gap’ is mainly produced by low number statistics and possibly observational biases. On the other hand, we find that Swift J1357−0933 contains a $10.9^{+1.7}_{-1.6}$ M⊙ BH, seen nearly edge on ($i=87.4^{+2.6}_{-5.6}$ deg). Such extreme inclination, however, should be treated with caution since it relies on extrapolating the T–i correlation beyond i ≳ 75○, where it has not yet been tested.

Numerical simulation of ground surface settlement of underpass building in tunnel boring machine double-line tunnels

Ground surface settlement under subway tunnel construction is one of the main sources of urban ground surface settlement, which may threaten the safety of existing buildings. Therefore, it is necessary to study the influence of subway tunnel construction on the safety and stability of surface subsidence. In the current study, the ground settlement originating from the operation of a tunnel-boring machine (TBM) while excavating a double-line tunnel that underpasses existing buildings is studied. To this end, numerical simulations were carried out and experimental data were analyzed. The boring parameters for the underpass interval section were derived by simulating the construction process and analyzing the TBM parameters in a real project. Then, the influence of thrust force, grouting pressure, and frictional force was considered on the surface settlement. For spatial locations between the existing buildings and the tunnel in the underpass area, the width of the ground surface settlement caused by different excavation sequences of the TBM two-line tunnel was analyzed. The obtained results demonstrate that the performed calculations are consistent with the monitoring data. It is found that the width and depth of the ground surface settlement trough are affected by the distance between the existing buildings and the TBM construction tunnel. However, the settlement location is independent of the excavated sequence but depends on the location of the TBM tunnel and the existing building.

Viscosity and structure evolution of molten vanadium slag during carbothermic reduction process

In this study, the viscosity and structure evolution of molten vanadium slag at different stages during carbothermic reduction process were investigated through employing the rotating cylinder technique, Fourier transformation infrared (FTIR) and Raman spectroscopy. The results showed that both the viscosity and apparent activation energy of the slag continuously increased with the decrease of FeO and MnO contents, while decreased with the decrement of Cr2O3 and V2O3 contents. The mole fractions of Q2 and Q3 units in the silicate melt increased significantly due to the decrease in the concentration of free oxygen with the reduction of FeO and MnO, and the structural units transformed from prevalent Q0 and Q1 to Q2 and Q3 dominant, resulting in the fact that the trough depth of the [SiO4]-tetrahedral band was obviously enhanced and its center shifted to a higher wavenumber region in the FTIR spectroscopy. On the contrary, the reduction of Cr2O3 and V2O3 brought a gradual increasing Q0 and Q1 concentration and lower polymerization degree of molten slag, while the trough depth of the [SiO4]-tetrahedral band was weakened and its center shifted to a lower wavenumber region, which responded well to the viscosity variation of the slag.

Objective Assessment of the Effectiveness of the Transconjunctival Fat-Repositioning Technique Using Magnetic Resonance Imaging and Three-Dimensional Surface Imaging.

Background: To quantify the surgical outcomes of transconjunctival fat repositioning technique, we study the lower periorbital area with magnetic resonance imaging (MRI) and three-dimensional (3D) surface imaging. Methods: The preoperative and postoperative images were analyzed. The T1-weighted MR images in the quasi-sagittal plane parallel to the long axis of the orbit and passing through the globe center were used to measure the transposed fat, and 3D comparison was performed to calculate the tear trough depth. Changes throughout the surgery and their relationships with clinical characteristics were statistically analyzed. Results: A total of 11 patients who underwent surgery were included. The mean follow-up period was 10.1 months. MRI measurements showed that the fat area beneath the tear trough increased from 0 to 22.7 ± 6.7 mm2 after fat repositioning, whereas the fat area of the eyelid bag decreased from 46.3 ± 11.0 mm2 to 25.5 ± 14.0 mm2. The 3D results revealed an increase in thickness by 1.2 ± 0.4 mm in the tear tough areas. Conclusion: Both MRI and 3D imaging provide options to objectively assess the fat-repositioning technique.

Pseudo magnetic properties and evidence for vortex state in Fe2NiGe Heusler alloy thin films

We report on the anisotropy, pseudo magnetic properties and formation of vortex state in Fe2NiGe thin films. From the torque measurements, estimated anisotropy constants K1 and K2 are found to be 4.47 × 103 J/m3 and −1.98 × 102 J/m3 respectively. Pseudo magnetic properties such as pseudo hysteresis work and pseudo remanence work infer that motion of domain wall in Fe2NiGe is rather smooth. The crest height and trough depth coefficient from the second stage of magnetization curves are estimated and are found to be 9.44 × 106 (A/m).mT and 8.76 × 106 (A/m).mT respectively. First order reversal curves infer switching field distribution is very small, which infers that less dislocations and more grain size. Indeed, the vortex state is evident from the contour graph of the first order reversal curves. We believe present results would be helpful for the future spintronic devices based on Heusler alloy thin films.

Impact damage to the middle trough of a scraper conveyor based on the engineering discrete element method and orthogonal matrix analysis.

The middle trough serves as a key part of a scraper conveyor. During the working process, falling raw coal lands on the middle plate of the trough, causing impact damage. This study aims to find the optimal working condition combination to minimize impact damage to the middle trough based on the engineering discrete element method (EDEM) and orthogonal matrix analysis (OMA). In EDEM software, simulation data of the impact damage depth and normal cumulative contact energy of the middle trough corresponding to the four influencing factors of the transverse laying roll angle, front lean angle, raw coal particle size, and chain layout and spacing under different horizontal conditions are obtained. Matrices of the impact damage depth and normal cumulative contact energy are separately established. Based on the respective factor layer, level and evaluation index weight matrices, a global weight matrix is finally obtained. The optimal combination of working conditions is obtained, and the weight of each factor on impact damage to the middle trough is determined by the weight coefficient. The accuracy of the simulation results is then verified in experiments. Among the considered factors, the raw coal particle size achieves the highest impact damage coefficient. When the raw coal particle size is the smallest (0.5 times the basic particle size), the transverse roll angle and front lean angle of the middle trough are positive (5° and 10°, respectively), the chain adopts the double-center chain arrangement, and minimal impact damage to the middle trough occurs. OMA reduces the test times to determine the optimal working conditions of a scraper conveyor.

Second harmonic generation from GaAs-Au subwavelength relief gratings

We study numerically the second-harmonic generation (SHG) from subwavelength GaAs relief gratings with and without Au nano-stripes on the bottom of grating troughs. The SHG efficiency is calculated by finite element method as a function of grating amplitude, Au-stripes thickness, depth of trough for TE and TM polarized fundamental harmonic. Our results show that a deep subwavelength grating without Au stripes can be considered as a homogeneous film when the grating period is 3.5 times shorter than the wavelength. Such a grating with a certain amplitude enhances the SHG efficiency by about 20 times compared with the efficiency of a crystal with flat surface. The Au-stripes at the grating troughs significantly increase the electromagnetic field concentration in the crystal ridges of the grating due to plasmonic resonance. In this case, the SHG efficiency enhancement is more than 500 times, while the absolute value of SHG efficiency reaches 1.2 × 10−3% when the intensity of pump light is 1 GW/cm2.