Search Results (16)

Cape Canaveral, home to critical space exploration infrastructure, is facing potential flooding hazards from land subsidence and sea-level rise. This study utilized three geodetic datasets, the Interferometric Synthetic Aperture Radar (InSAR), the Global Navigation Satellite System (GNSS), and precise leveling, to investigate the spatial and temporal patterns of vertical land motion (VLM) in Cape Canaveral and its surrounding areas. Our analysis revealed that Cape Canaveral experiences both long-term regional subsidence and localized subsiding areas, while Merritt Island and the Peninsular Mainland remain relatively stable. The long-term regional subsidence in Cape Canaveral is likely driven by the compaction of younger, unconsolidated siliciclastic sediments, with a small contribution from glacial isostatic adjustment (GIA). The three localized subsiding areas identified in Cape Canaveral are each driven by distinct mechanisms: wetland modification in the western area, runway infrastructure development in the central area, and the natural compaction of young siliciclastic sediments in the southeastern region. Historical leveling data indicated temporal variations in subsidence rates at Cape Canaveral, from 5 mm/yr during the 1950–70s to 2 mm/yr in the 2000s. These findings have significant implications for infrastructure resilience and flood hazard assessment, as the observed subsidence compounds with the projected accelerated sea-level rise in the region. Our results highlight the importance of integrating long-term datasets to better characterize VLM in the dynamic coastal region for effective planning and risk mitigation. Full article

Small-modulus gears, which are essential for motion transmission in precision instruments, present a measurement challenge due to their minuscule gear gaps. A high-precision measurement method under the influence of positioning errors is proposed, enabling precise evaluation of the machining quality of small-modulus gears. Firstly, a compound measurement platform for small-modulus gears is developed. Using a 3D model of the measurement system, the mathematical relationships governing motion transmission between various components are analyzed. Secondly, the formation mechanism of gear positioning error is revealed and its important influence on measurement accuracy is discussed. An optimization method for spatial coordinate transformation matrices under positioning errors of gears is proposed. Thirdly, the study focuses on small-sized gears with a modulus of 0.1 mm and a six-level accuracy. Based on the aforementioned measurement system, the tooth profile measurement points are collected in the actual workpiece coordinate system. Then, gear error parameters are extracted based on the established models for tooth profile deviation and pitch deviation. Finally, the accuracy and effectiveness of the proposed measurement method are verified by comparing the measurement results of the P26 gear measuring center. Full article

This study aims to optimize the frying process of natural porous materials (like potatoes) by enhancing heat and mass transfer phenomena through significant horizontal acceleration values following a spatially periodic pattern that alternates the intensity of inertia forces uniformly across the frying vessel. The generated horizontal inertial forces act complementary to the normal vertical buoyancy force for the creation of agitating convective currents in the oil and for vapor bubbles’ departure from the surface of frying objects. The use of an innovative frying device, employing simultaneous rotation around two vertical axes at a different speed in a so-called planetary type of motion, serves to facilitate this production of horizontal acceleration values that allows intensifying the performance of frying. The present investigation examines the impact of rotational speed, along with oil temperature and frying duration, on the water loss and sensory evaluation of fried items. The potato-to-oil ratios typically found in industrial frying operations are employed. The intended outcome is a more energy-efficient frying process, reduced cooking times, and a healthier product due to lower frying temperatures and the consequent decreased formation of harmful compounds. This approach carries substantial implications for food processing, potentially enhancing productivity while limiting operational costs. Full article

The characterization of landslides located in remote areas poses significant challenges due to the costs of reaching the sites and the lack of reliable subsurface data to constrain geological interpretations. In this paper, the advantages of combining field and remote sensing techniques to investigate the deformation and stability of rock slopes are demonstrated. The characterization of the Fels landslide, a large, slowly deforming rock slope in central Alaska, is described. Historical aerial imagery is used to highlight the relationship between glacier retreat and developing instability. Airborne laser scanning (ALS) and Structure-from-Motion (SfM) datasets are used to investigate the structural geological setting of the landslide, revealing a good agreement between structural discontinuities at the outcrop and slope scales. The magnitude, plunge, and direction of slope surface displacements and their changes over time are studied using a multi-temporal synthetic aperture radar speckle-tracking (SAR ST) dataset. The analyses show an increase in displacement rates (i.e., an acceleration of the movement) between 2010 and 2020. Significant spatial variations of displacement direction and plunge are noted and correlated with the morphology of the failure surface reconstructed using the vector inclination method (VIM). In particular, steeper displacement vectors were reconstructed in the upper slope, compared to the central part, thus suggesting a change in basal surface morphology, which is largely controlled by rock mass foliation. Through this analytical approach, the Fels landslide is shown to be a slow-moving, compound rockslide, the displacement of which is controlled by structural geological features and promoted by glacier retreat. Full article

Rotating machinery condition monitoring and fault diagnosis are important bases for maintenance decisions, as the vibrations generated during operation are usually imperceptible to the naked eye. Eulerian video motion magnification (EVMM) can reveal subtle changes and has been widely used in various fields such as medicine, structural analysis, and fault diagnosis, etc. However, the method has a bound relationship among three parameters: spatial wavelength, amplification factor, and displacement function, so it is necessary to adjust the parameters manually in practical applications. In this paper, on the basis of the original method, an automatic solution of spatial cutoff wavelength based on brightness is proposed. First, an input video is decomposed into image sequences, their RGB color spaces are transformed into HSV color spaces, and the Value channel image representing brightness is selected to automatically calculate the spatial cutoff frequency, and then the spatial cutoff wavelength is determined, and the motion magnification video in the specified frequency band is obtained by substituting it into the original method. Then, a publicly available video is taken as an example for simulation analysis. By comparing the time-brightness curves of the three videos (original video, motion magnification video obtained by the original method and the improved method), it is apparent that the proposed method exhibits the most significant brightness variation. Finally, taking an overhung rotor-bearing test device as the object, five conditions are set, respectively: normal, rotor unbalance, loosened anchor bolt of the bearing seat, compound fault, rotor misalignment. The proposed method is adopted to magnify the motion of the characteristic frequency bands including 1X frequency and 2X frequency. The results show that no obvious displacement is found in normal working conditions, and that the rotor unbalance fault has an overall axial shaking, the bearing seat at the loose place has an obvious vertical displacement, while the compound fault combines the both fault characteristics, and the rotor misalignment fault has an obvious axial displacement of the free-end bearing seat. The method proposed in this paper can automatically obtain the space cutoff wavelength, which solves the problem of defects arising from manually adjusting the parameters in the original method, and provides a new method for rotating machinery fault diagnosis and other fields of application. Full article

Flow motion with complex patterns, such as vortex, stagnant flow, and seepage, put forward higher spatial resolution requirements for particle image velocimetry (PIV). With the development of deep learning technology in optical flow estimation, many attempts have been made to introduce deep learning-based optical flow (DLOF) into PIV. Compared with the traditional optical flow method, the DLOF method has the advantages of higher precision, faster calculation speed, and avoiding manual parameter adjustment. However, DLOF research is generally developed based on the basic characteristics of rigid body motion, and its key loss function part still generally uses the L1 (mean absolute error, MAE, L1) or L2 (mean square error, MSE, L2) loss functions, which lack consideration of fluid motion characteristics. Therefore, the current DLOF research has the problems of large angular error and serious curl-divergence loss in fluid motion estimation scenarios with smaller spatial scales than rigid bodies. Based on the prior knowledge of the traditional fluid motion characteristics, this study proposes a fluid loss function for describing the fluid motion characteristics, and combines this loss function with Flownet2. The compound loss (CL) function is combined with the displacement error, angular error, and div-curl smooth loss. The method combined with the loss function in this paper is called FlowNet2-CL-PIV. In order to verify that the compound loss function proposed in this study has a positive impact on the model training results, this paper uses the cosine similarity measure to demonstrate its effectiveness. In addition, the parameter selection of the compound loss function is analyzed and compared, and it is verified that the best training effect can be achieved by adjusting the parameter so that the order of magnitude of each part of the compound loss function is consistent. In order to test the calculation effect of the Flownet2-CL-PIV method proposed in this study, synthetic particle images are used for model training and performance analysis. Simulation results in various flow fields show that the root mean square error (RMSE) and average angular error (AAE) of Flownet2-CL-PIV reach 0.182 pixels and 1.7°, which are 10% and 54% higher than the original model, respectively. Full article

Capacity is the important indicator of the cone crushers, which is determined by the motion characteristics of particles. The spatial compound motion of the mantle, which rotates both around the central axis of the cone crusher and its central axis, was analyzed to develop motion characteristic equations of particles. The velocity distribution of particles with different motion characteristics was determined by solving the motion characteristic equations of particles using the coordinate system transformation matrix. An improved capacity model of the cone crushers based on the motion characteristics of particles considering the influence of the spatial compound motion of the mantle was established by analyzing the velocity of particles in the upward and downward direction zones of the choke-level and the influence of circumferential deflection of particles on the velocity in the radial direction. A reduced-scale cone crusher with various rotational speeds was used to simulate cone crushers with different motion characteristics of the particles passing through the choke-level. The average error between the capacity calculated by the improved capacity model and the capacity determined according to the experimental data was 5.96%. Therefore, the accuracy of the improved capacity model was verified. The improved capacity model was used in the capacity calculation of the ZS200MF cone crusher; the error was 7.4% compared with the measured value at the production site; thus, the applicability of the improved capacity model is proved. The influences of four typical parameters of the cone crusher on capacity were investigated based on the improved capacity model, which provides theoretical support for the development of new high-efficiency cone crusher and the optimization of existing equipment. Full article

Natural channels often consist of a mainstream near their thalwegs and shallow vegetated areas near shores. The compounded and partially vegetated cross-sections play a significantly role in determining the hydrodynamic characteristics of a channel. By employing the Lagrangian Coherent Structure (LCS) analysis, the present work unravels the effect of vegetation and geometry on the hydrodynamic interactions between mainstreams with the various depths and vegetated shallow areas. The LCS method is the concept of dynamical system analyses, which is determined by the finite-time Lyapunov exponents (FTLE) field of fluid particles. It enables to overcome the limitations of using the particle tracking method in cost and time for simulations. Since the LCSs represent material surfaces or asymptotic lines which particles approach, but do not pass through, they match well with the trajectories of particles or materials obtained by solving particle motion equations. Therefore, the temporal and spatial developments of the interfacial layers could be investigated by using the FTLE. As the difference of depth becomes appreciable, the values of FTLE are relatively larger farther from the vegetated area. It implies that the interfacial layer becomes wider with the larger size of vortex produced by the differences of velocities between the mainstreams and the vegetated areas. In other words, as depth differences become large, materials and momentum can be spread from the vegetated area to or collected from a wider area of the mainstream. Full article

The cone crusher is the main equipment in the particle crushing process. The productivity of the cone crusher is determined by the motion characteristics of particles passing through the crushing chamber. In order to accurately describe the motion characteristics of the particles, the influence of the spatial compound motion of the mantle rotates around the central axis of the cone crusher and its central axis on the motion characteristics of the particles is investigated, then the improved motion model is established. Through the coordinate system transformation matrix, the motion characteristics of the particles including spatial sliding, free-falling, and spatial compound falling are solved. The applicability and accuracy of the improved model in describing the motion characteristics of the particle were verified through the experiment using a reduced-scale experimental cone crusher to simulate the motion characteristics of the particle. Based on the improved model, the motion characteristics of the particles in the CF11 hydraulic cone crusher can be simulated. With the decrease in height, the motion characteristics of particles gradually change from spatial sliding to spatial compound falling and finally to free-falling. The particles deflect circumferentially around the central axis of the cone crusher. The circumferential deflection of particles is directly related to the motion characteristics including spatial sliding and spatial compound falling. The improved model provides a theoretical basis for the high energy design of the crushing chamber and productivity improvement of the cone crusher. Full article

The aim of this study is to offer a comprehensive view on drug release from hydrogel, from both an experimental and a theoretical point of view. Aiming to benefit cyclodextrins’ properties (not irritant; stable; able to modify the physical, chemical and biological properties of active compounds; accessible at low prices) and those of carrageenan polysaccharide (antitumor, immunomodulatory, antihyperlipidemic, anticoagulant, biocompatibility, biodegradability), original hydrogel films based on beta cyclodextrin and kappa carrageenan using epichlorohydrin as crosslinking agent were prepared and characterized from morphological and physical/chemical points of view. The results (morphology, the swelling degree, and the loading/release capacity) proved their potential as carriers for different types of drugs. Further, a new theoretical model, from a multifractal paradigm of motion, was proposed for the drug release from hydrogel films, starting from the fundaments of its evolution at a microscopic level, and aiming to obtain information on system evolution, at both the spatial and temporal scales, inapproachable by quantitative measurements. Full article

While Uncrewed Aerial Vehicle (UAV) systems and camera sensors are routinely deployed in conjunction with Structure from Motion (SfM) techniques to derive 3D models of fluvial systems, in the presence of vegetation these techniques are subject to large errors. This is because of the high structural complexity of vegetation and inability of processing techniques to identify bare earth points in vegetated areas. Furthermore, for eco-geomorphic applications where characterization of the vegetation is an important aim when collecting fluvial survey data, the issues are compounded, and an alternative survey method is required. Laser Scanning techniques have been shown to be a suitable technique for discretizing both bare earth and vegetation, owing to the high spatial density of collected data and the ability of some systems to deliver dual (e.g., first and last) returns. Herein we detail the development and testing of a UAV mounted LiDAR and Multispectral camera system and processing workflow, with application to a specific river field location and reference to eco-hydraulic research generally. We show that the system and data processing workflow has the ability to detect bare earth, vegetation structure and NDVI type outputs which are superior to SfM outputs alone, and which are shown to be more accurate and repeatable, with a level of detection of under 0.1 m. These characteristics of the developed sensor package and workflows offer great potential for future eco-geomorphic research. Full article

In this work, the effect of molecular cosolvents tetraethylene glycol dimethyl ether (TEGDME) on the structure and versatile nature of mixtures of these compounds with imidazolium-based ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF₆]) is analyzed and discussed at a molecular level by means of all-atom molecular dynamics (MD) simulations. In the whole concentration range of the binary mixtures, the structures and properties evolution was studied by means of systematic molecular dynamics simulations of the fraction of hydrogen bonds, the radial and spatial distribution functions for the various molecular ions and molecular species in the system, together with the snapshots visualization of equilibrated simulation boxes with a color-coding scheme and the rotational dynamics of coumarin 153 (C153) in the binary mixtures. The goal of the work is to provide a molecular-level understanding of significant improvement of ionic conductivity and self-diffusion with the presence of TEGDME as a cosolvent, which causes an enhancement to the ion translational motion and fluidity in the [bmim][PF₆] ionic liquids (ILs). Under a mixture concentration change, the microstructure changes of [bmim][PF₆] with the TEGDME molar fraction (X_TEG) above 0.50 show a slight difference from that of neat [bmim][PF₆] IL and concentrated [bmim][PF₆]/TEGDME mixture in terms of the radial and spatial distribution functions. The relative diffusivities of solvent molecules to cations as a function of concentration were found to depend on the solvent but not on the anion. A TEGDME increase is found to be advantageous to the dissipation of the polar regions as well as the nonpolar regions in the [bmim][PF₆] ionic liquids. These conclusions are consistent with the experimental results, which verified that the unique, complex, and versatile nature of [bmim][PF₆]/TEGDME mixture can be correctly modeled and discussed at a molecular level using MD simulation data. Full article

The curve-face gear pair is a new type of gear pair with variable transmission ratio for spatial finite helical motion. In this paper, mathematical models of a new developed curve-face gear were simplified and obtained directly by the standard shaper. The subsequent studies on the curve-face gear compound transmission characteristics were further analyzed by the combinations of the principle of space gearing and screw theory. Firstly, the conjugate tooth surface geometry as well the point contact traces of curve-face gears were derived. Secondly, the geometric relationships between gear pair and the corresponding meshing characteristics were evaluated by several basic geometric elements, including instantaneous screw, axodes, striction curve, and conjugate pitch surface. Based on that analysis, it was found that the tooth contact normal was reciprocal to the instantaneous twist, which demonstrated that the conjugate motion with the desired transmission ratio could be realized in current curve-face gear compound transmission. Moreover, the time-varying slip characteristics of the curve-face gear pair were also revealed, that is, rolling and sliding action coexist at all contact on the tooth surfaces. In brief, this work provided the theoretical basis for following researches on machining curve-face gear with standard shaper. Full article

Over the past few decades the country of Qatar has been one of the fastest growing economies in the Middle East; it has witnessed a rapid increase in its population, growth of its urban centers, and development of its natural resources. These anthropogenic activities compounded with natural forcings (e.g., climate change) will most likely introduce environmental effects that should be assessed. In this manuscript, we identify and assess one of these effects, namely, ground deformation over the entire country of Qatar. We use the Small Baseline Subset (SBAS) InSAR time series approach in conjunction with ALOS Palsar-1 (January 2007 to March 2011) and Sentinel-1 (March 2017 to December 2019) synthetic aperture radar (SAR) datasets to assess ground deformation and conduct spatial and temporal correlations between the observed deformation with relevant datasets to identify the controlling factors. The findings indicate: (1) the deformation products revealed areas of subsidence and uplift with high vertical velocities of up to 35 mm/yr; (2) the deformation rates were consistent with those extracted from the continuously operating reference GPS stations of Qatar; (3) many inland and coastal sabkhas (salt flats) showed evidence for uplift (up to 35 mm/yr) due to the continuous evaporation of the saline waters within the sabkhas and the deposition of the evaporites in the surficial and near-surficial sabkha sediments; (4) the increased precipitation during Sentinel-1 period compared to the ALOS Palsar-1 period led to a rise in groundwater levels and an increase in the areas occupied by surface water within the sabkhas, which in turn increased the rate of deposition of the evaporitic sediments; (5) high subsidence rates (up to 14 mm/yr) were detected over landfills and dumpsites, caused by mechanical compaction and biochemical processes; and (6) the deformation rates over areas surrounding known sinkhole locations were low (+/−2 mm/yr). We suggest that this study can pave the way to similar countrywide studies over the remaining Arabian Peninsula countries and to the development of a ground motion monitoring system for the entire Arabian Peninsula. Full article

Ultrafast compound Doppler imaging (UCDI), which can be used to acquire Doppler information at very high spatial and temporal sampling rates, provides a great improvement to the characterization of the vasculature. The singular value decomposition (SVD) technique takes advantage of the different features of tissue and blood motion in terms of spatiotemporal coherence and strongly outperforms conventional clutter rejection filters in small animals. However, a major challenge of conventional UCDI with SVD clutter filtering for small vessel imaging is that it is not sensitive enough to detect the hemodynamic changes in deep tissue where the majority of the remaining signal is usually noise-saturated. In this study, with the first attempt to apply ultrasonic tissue characterization techniques to UCDI, we propose an H-scan subtraction Doppler imaging method to bypass the limitations associated with the high-order singular value thresholding selection and improve the image quality of fine vessels. The flow phantom experiments with different blood concentrations show that H-Scan is capable of estimating the relative size and spatial distribution of acoustic scattering objects. In the in vivo rabbit brain experiment, the H-Doppler method, together with the global and block-wise local SVD clutter filtering, are proposed to facilitate better power Doppler images with a significant improvement of background noise suppression. These results demonstrate that the contrast-to-noise-ratio (CNR) of the H-scan subtraction Doppler imaging is 15% to 65% higher than that of the conventional UCDI methods. Therefore, this approach can be potentially applied to the clinical applications of the functional ultrasound (fUS) imaging method. Full article