Capture Points Research Articles

A common framework for the development of spring water contamination early warning system in western Mediterranean karst areas: Spanish and French sites

Karst water resources, traditionally used worldwide for drinking purposes, are highly vulnerable to contamination. Scientific-technical efforts must therefore be done to ensure sufficient water quality for human consumption. Early-Warning-Systems emerge as an effective spring scale protection strategy for real-time identification of contamination episodes at drinking water capture points. With this ambition, the proposed stepwise procedure for the implementation of site-specific Early-Warning-Systems (EWS), focuses on three critical features: identification of groundwater contamination proxy parameters, warning dissemination and system validation. It was tested at three karst springs affected by temporary faecal contamination and intended for supplying drinking water to populations in Spain (Ubrique) and France (Montpellier). The applied statistical techniques, coupled to the analysis of individual flood events at karst springs, allowed to identify the optimal combination of groundwater and contamination proxy parameters at each study site according to the main contaminants and recharge mechanisms. The decision tree-like workflow, used to evaluate groundwater quality at hourly time step and set up the EWS, was then constructed considering a specific combination of hydroclimatic, hydrodynamic and physical variables together with national regulations for drinking water. Hence, warning thresholds were adapted to the behaviour of each karst system, and used to trigger the alarm when specific parameters and proxies exceeded the defined limits. The performance of the EWS was assessed by implementing 4 specific Key Performance Indicators (KPIs) dedicated to appreciate the effectiveness of the workflows in identifying contamination events and verifying estimated warning thresholds. The performed analysis demonstrated an overall successful functioning of the EWS for the three case studies, with mean anticipation times ranging between 12 and 45 h and <3 % of failure rate.

Reflectance characterization of Starlink-like satellite with HELIOS brightness testing facility

The HELIOS (High Efficiency Light Intensity Observation System) project addresses the issue of excessive brightness from LEO satellite constellations. The system aims to develop a reflectance model of a satellite prior to launch, enabling the validation of compliance with astronomer guidelines, which suggest a minimum magnitude of 7. This ensures that the constellation is not visible to the naked eye and does not excessively interfere with astronomical observations. Additionally, the reflectance model obtained can be used for attitude determination by comparing the light curves with those obtained from observations. This application extends to Space Traffic Management, debris reentry prediction, and active debris removal. The system utilizes a light source consisting of 14 high-power LEDs with different wavelengths that replicate the solar spectrum. The light is positioned on an arc and can slide along a rail, allowing sampling at various angles. The arc itself can rotate on its axis, enabling the placement of the light source at any point on the hemisphere. At the center of the hemisphere, a scaled 3D printed model of the satellite under study is placed, with surface finishes resembling the actual satellite. Creating models with varying levels of detail permits to assess their impact on the reflectance model. Finally, the robotic arm Arm4NDO (Arm For Near Distance Observations) permits the movement of a high-efficiency quantum camera mounted at its end across the entire hemisphere’s surface for data acquisition. The camera records a video, stopping at points of interest for capturing frames. To strike a balance between continuous data acquisition and reasonable testing times, both the light source and capture points are positioned every 15° in elevation and azimuth. The initial test campaign aimed to determine optimal camera settings (exposure, aperture, and ISO) to achieve good model visibility and a dark background. Preliminary tests focused on Starlink’s chassis and the most significant observation configurations. Frames of interest were extracted from the videos, and their luminous flux (sum of pixel intensity values) was derived. With the obtained data, curves normalized relative to the maximum were plotted, allowing for a comparison of flux variations among different configurations.

Deciphering Martian Flood Infiltration Processes at Hebrus Valles: Insights From Laboratory Experiments and Remote Sensing Observations

AbstractIn evaluating the unique geomorphology of Hebrus Valles on Mars, an outflow channel southeast of Utopia Planitia, we investigated the role of fluvial dynamics in forming subsurface conduits. Unlike typical Martian channels that terminate under younger sediment rocks, Hebrus Valles retains its downstream features, thus offering a window into surface and subsurface interactions between liquid water and regolith. Employing physical lab simulations, we utilized buried polygonal tunneling configurations in a sandy matrix to replicate the incision features observed at the channel's terminus. This study provides the first lab‐based evidence demonstrating the role of conduits in conveying large floods in the Hebrus Valles. Our results lend support to the interpretation that Hebrus Valles conveyed high‐volume floods by demonstrating that conduits are necessary to form the features observed on the surface of Hebrus Valles. The experiments also highlight the role of sinkholes as floodwater capture points, which suggests the formation of a regional interconnected network of subsurface channels and caverns. These findings affirm that fluvial dynamics in Hebrus Valles could have expanded subsurface discontinuities into functioning conduit systems, potentially directing floodwaters through an interconnected subterranean network.

Dual biomimetic surfaces with anisotropic wettability for multi-scale droplets manipulation

Droplets manipulation on functional biomimetic surfaces have been highly anticipated for their wide range of applications. However, preparing a metal platform for manipulating multi-scale droplets without external energy input remains a challenge. Herein, dual biomimetic surfaces (DBSs) were fabricated by twice laser and thiol modification. The unique interfacial behavior of the droplets can be realized under the synergistic effect of the special “millimeter-micrometer-nanometer” multi-hierarchical composite structure and chemical composition. The as-prepared DBSs can achieve multi-scale droplets manipulation, directional self-cleaning in various media, and efficient directional fog collection. Further, the mechanism of specific interface behavior is analyzed in depth. Nanoparticles endow DBSs with more capture points and condensation cores and micrometer mastoids realized the transmission and aggregation of microscopic droplets through the action of Laplace force. Based on resistance, energy barriers and three-phase contact line, influence of millimeter grooves on anisotropic wettability and directional transportation of the droplets is analyzed. Besides, the multi-hierarchical structure also endows DBSs with good droplets manipulation ability and stability. This work not only provides an advanced biomimetic platform, but also provides an important reference for metal-based lab-on-a-chip for multi-scale droplets manipulation.

Parentage of 920 gray‐sided voles (Myodes rufocanus) born in a 3‐ha outdoor enclosure between September 1992 and May 1994

AbstractThis dataset provides the estimated birth location, sex, assigned parents, and estimated birth and death dates of 920 gray‐sided voles (Myodes rufocanus) born in a 3‐ha outdoor enclosure in Sapporo, Japan between September 1992 and May 1994, as well as capture–recapture data for 30 trapping sessions. We introduced 22 males and 25 females from several natural populations into the enclosure in late September 1992. Individuals in the enclosure were captured using live traps every 2 weeks until late April 1994, except for periods with deep snow cover. The location, body weight, and reproductive status of each vole were monitored throughout the study period. Complementary trapping was performed within the home ranges of breeding females to mark juveniles as early as possible. Upon first capture, each individual was marked by toe clipping for subsequent identification, and the clipped toes were used as DNA samples. For each individual, candidate parents were selected based on female reproduction history and capture points. Parentage then was determined using genotypes at 3–5 microsatellite loci with the CERVUS program. The results show that individuals born in the enclosure (N = 920) were derived from 215 litters, among which multiple males sired 51 litters. We used this database to elucidate the promiscuous mating system and inbreeding‐avoidance mechanism of the gray‐sided vole and to develop a new method for estimating the frequency of multiple‐male mating. This dataset will contribute to future behavioral ecological research on this and other small mammal species. The complete data set for this abstract published in the Data Article section of the journal is available in electronic format in MetaCat in JaLTER at http://db.cger.nies.go.jp/JaLTER/metacat/metacat/ERDP-2023-03.1/jalter-en.

Enhancing fog collection by optimizing wettability combination and fork-row collector arrangement: light and heavy fog

Fog collection is essential to alleviate water scarcity in arid areas. However, the vast majority of existing fog collectors only work effectively in heavy fog. To broaden the fog concentration range for efficient work, an optimization strategy based on wettability combination and fork-row arrangement is proposed in this work. Single-layer experiment results show that a hydrophilic (HL) surface with high deposition capacity collects droplets at a faster rate in light fog (25–80 g h−1), while the collection rate of a hydrophobic (HB) surface with high drainage capacity is higher in heavy fog (220–500 g h−1). Double-layer experiment results show that in light fog, the best combination of double-layer collection electrodes is HL–HL, while HB–HL performs best in heavy fog. A 35% improvement in collection rate can be obtained simply by changing the arrangement from smooth-row (S) to fork-row (F), which is attributed to the increased effective collision area of droplets. In our series of experiments, at 50 g h−1, the collection rate of double-layer combination HL–HL(F) is 56.7% higher than that of single-layer HL. In particular, the collection rate of HB–HL(F) reaches 1434.7 mg cm−2 h−1 at 500 g h−1. Such a good performance is attributed to the force imbalance of hanging droplets caused by wettability differences, which tends to transport small droplets on HB towards HL directionally, resulting in a rapid droplet slippage. Therefore, the HB–HL accelerates drainage and refreshes capture points. Furthermore, fog collection performance is also influenced by layer spacing, which has an optimal distance. These findings provide a promising method for practical applications of fog collectors in a wide range of fog flow quantities, enhancing adaptability to variable environments.

High-precision plant height measurement by drone with RTK-GNSS and single camera for real-time processing

Conventional crop height measurements performed using aerial drone images require 3D reconstruction results of several aerial images obtained through structure from motion. Therefore, they require extensive computation time and their measurement accuracy is not high; if the 3D reconstruction result fails, several aerial photos must be captured again. To overcome these challenges, this study proposes a high-precision measurement method that uses a drone equipped with a monocular camera and real-time kinematic global navigation satellite system (RTK-GNSS) for real-time processing. This method performs high-precision stereo matching based on long-baseline lengths (approximately 1 m) during the flight by linking the RTK-GNSS and aerial image capture points. As the baseline length of a typical stereo camera is fixed, once the camera is calibrated on the ground, it does not need to be calibrated again during the flight. However, the proposed system requires quick calibration in flight because the baseline length is not fixed. A new calibration method that is based on zero-mean normalized cross-correlation and two stages least square method, is proposed to further improve the accuracy and stereo matching speed. The proposed method was compared with two conventional methods in natural world environments. It was observed that error rates reduced by 62.2% and 69.4%, for flight altitudes between 10 and 20 m respectively. Moreover, a depth resolution of 1.6 mm and reduction of 44.4% and 63.0% in the error rates were achieved at an altitude of 4.1 m, and the execution time was 88 ms for images with a size of 5472 × 3468 pixels, which is sufficiently fast for real-time measurement.

Nonlinear kinematics of space parallel robot with Bricard mechanism

The space parallel robot with Bricard mechanism (SPRBM) is a complex mechanical device used for capturing free-floating space debris. It consists of a 3-RRS (Revolute-Revolute-Spherical Joints) parallel mechanism and a Bricard mechanism. Space debris can be captured by the interior space of the SPRBM. Compared with the conventional manipulator system, the SPRBM can capture a target with an arbitrary shape and motion state if the target can be enwrapped by the mechanism. In addition, it does not impose any stringent requirement on the locations of the capture points on the debris. However, the SPRBM has complex configurations and therefore nonlinear kinematics. This paper presents a detailed kinematics analysis of the SPRBM. The analysis involves the degrees of freedom, singularity, forward and inverse kinematics, workspace, and the trajectory planning method. These analyses and the results provide the fundamentals for modeling and controlling the SPRBM.

Nitrogen and carbon stable isotope analysis sheds light on trophic competition between two syntopic land iguana species from Galápagos

Coexistence between closely related species can lead to intense competition for resources. Stable isotope analysis (SIA) is a reliable tool to estimate the extent of species competition. We employed SIA to evaluate niche partitioning among two syntopic species of Galápagos land iguanas: Conolophus subcristatus and C. marthae. Samples were collected on Wolf Volcano, Isabela Island, where C. marthae is endemic and syntopic with C. subcristatus. We determined δ13C and δ15N ratios and described the isotopic niche of each species using corrected standard ellipse area (SEAc). We tested for differentiation between the isotopic niches, while controlling for sex, body size, spatial location of samples and mean annual primary productivity at capture points, using bivariate linear models. Despite the extensive overlap of the isotopic niches, we found species and sex to be a significant, interacting predictor of a sample’s location in the δ13C, δ15N space, indicating the existence of niche partitioning mechanisms acting between species and sexes. We also found that body size and productivity at the capture points, compounded with yet undetermined spatial effects, explain ca. 75% of the differences observed between species and sexes, providing evidence for differential microhabitat and food-items usage. Our study provides essential baselines for evaluating conservation actions for C. marthae, such as the potential translocation to a sanctuary area free of competition from C. subcristatus.

Fatty acid, proximate composition and mineral content of Tenualosa sp. from east coast of India

This study investigated the proximate composition and fatty acid profiles of Tenualosa sp. (Tenualosa ilisha, Tenualosa keli) at three leading capture points on the east coast of India i.e., Chilika, Chandravaga, and Chandipur. The Tenualosa sp. contained 89.03, 7.52, 1.66, and 1.04% of moisture, protein, fat, and ash, respectively. Out of 33 detected fatty acid components, myristic acid (C14:0) (684.67 mg/100g) was found to be the predominant saturated fatty acid (SFA) content. The ω-3 and ω-6 PUFA contents in the fish flesh ranged between 123.4 and 239.43 (avg. 177.89 mg/100g) and 293.43–543.37 (avg. 391.96 mg/100g), respectively. The highest DHA of 1.29 mg/100g was registered for the Tenualosa sp. of Chilika lagoon. The atherogenicity indices (AI), thrombogenicity indices (TI), hypocholesterolaemia / hypercholesterolemic ratio (H/h) were found to be 1.5,0.63, and 0.62, respectively, and <2 which indicated safe for human consumption as per Food and Agriculture Organization of the United Nations (FAO-UN). The trace metal concentrations of copper (Cu), zinc (Zn), iron (Fe), chromium (Cr) were also recorded within the safe limit for consumption as suggested by the world health organisation (WHO). Hence, the Tenualosa sp. proved to be safe for consumption and can be regarded as a dietary component for good health.

Artificial Displacement Alters Movement Behavior of a Terrestrial Amphibian

Homing abilities have been widely documented in amphibians, but it remains unclear whether individuals have homing tendencies in the absence of motivational cues related to breeding and site fidelity. We tested whether artificial displacement would affect the movement behavior of a nonphilopatric terrestrial amphibian, the Fowler's Toad (Anaxyrus fowleri), within its home range and after its breeding season had ended. We translocated 65 male and female Fowler's Toads from their initial points of capture a total of 104 times over one of three different distances (100 m, 250 m, and 500 m) and compared these toads' subsequent 24-h movements with those of a control group of 43 untranslocated toads. To shield the translocated toads from auditory, visual, and olfactory cues en route, we translocated them in opaque enclosed boxes and performed the experiment in the uniformly unobstructed landscape of the Lake Erie shoreline of Long Point, ON, Canada. We mainly investigated directionality bias as the orientation between control and translocated groups, homing tendency as the correlation between movements after translocation and translocation distance, and homing accuracy as the variation in distance between final and initial capture points. Our results provide clear evidence that translocation changes the movement behavior of these toads and that they possess homing tendencies outside of their breeding season. Toads had a strong directional bias to move in the opposite direction to the one in which they were artificially displaced, in contrast with the control group, which showed no directional bias among 61 recorded 24-h movements. This tendency for amphibians to home after artificial displacement might be a significant confounding factor in any procedure involving their relocation.

Phenotypic Variations of Aedes aegypti Populations and Egg Abundance According to Environmental Parameters in Two Dengue-Endemic Ecoregions in Paraguay.

Dengue in Paraguay is an endemic disease of public health importance. Several studies suggest that an increased density of Aedes aegypti and the presence of dengue cases may be associated with climatic conditions. This study aimed to establish the phenotypic variations of Ae. aegypti from four cities (Asunción, Itauguá, Minga Guazú, and Ciudad del Este) and the potential association of environmental variables with the number of eggs in capture sites. Eleven morphometric phenotypic characters were evaluated, and environmental data were obtained from Earth Engine and local meteorological stations. An analysis was carried out using principal component analysis and linear discriminant analysis, and we estimated the correlation using [relative humidity, Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI)] between variables and the number of eggs in each site. Differences in mean NDVI and NDWI between cities and their relationship with the morphometric performance of individuals were also assessed. The study demonstrated morphometric variations between the populations of Ae. aegypti from two ecoregions, with the Litoral ecoregion populations presented a greater phenotypic variation than those observed in the Alto Paraná ecoregion. Significant statistical associations were registered between the number of eggs with relative humidity (r = -0.45) and the NDVI at 100 meters from the capture points (r = -0.61) for Minga Guazú, and with the NDWI at 100 meters (r = 0.54) for Ciudad del Este. Future studies on these Ae. aegypti populations, and its dispersion could contribute to improve vector control measures and foster future genetic studies.

Thermal evolution of microdefects in He ion irradiated W-Ni-Feheavy alloy

To investigate the thermal evolution of vacancy-type defects and the relationship between the evolution of vacancy-type defects and the formation of fuzz structure on the surface of W-Ni-Fe heavy alloys irradiated with He ions, isochronal annealing treatments at temperatures from 100 °C to 1000 °C were conducted on the irradiated 97W-2Ni-Fe alloy. The evolution of microdefects was characterized by positron annihilation spectroscopy (PAS). Thermal desorption spectroscopy (TDS), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) were used to supplement the positron annihilation method. A large number of vacancy-type defects were produced in the 97W-2Ni-Fe alloy after irradiation at room temperature and isochronal annealing, and the main defect types of positron capture changed at three stages: RT-600 °C, 600–800 °C, and 800–1000 °C. SEM found that a large number of nanoscale protrusions appeared on the surface of samples annealed at 800 °C, and these nanoscale protrusions were seeds of fuzz structures. The formation of fuzz structure is closely related to the movement of vacancy-type defects by PAS, TDS, SEM, and other characterization methods. In addition, we found that the high density Ni and Fe in the matrix phase of the 97W-2Ni-Fe alloy as He capture points would accelerate the nucleation and growth of He bubbles and promote the growth of the fuzz structure.

Comparative assessment of blue hydrogen from steam methane reforming, autothermal reforming, and natural gas decomposition technologies for natural gas-producing regions

Interest in blue hydrogen production technologies is growing. Some researchers have evaluated the environmental and/or economic feasibility of producing blue hydrogen, but a holistic assessment is still needed. Many aspects of hydrogen production have not been investigated. There is very limited information in the literature on the impact of plant size on production and the extent of carbon capture on the cost and life cycle greenhouse gas (GHG) emissions of blue hydrogen production through various production pathways. Detailed uncertainty and sensitivity analyses have not been included in most of the earlier studies. This study conducts a holistic comparative cost and life cycle GHG emissions’ footprint assessment of three natural gas-based blue hydrogen production technologies – steam methane reforming (SMR), autothermal reforming (ATR), and natural gas decomposition (NGD) to address these research gaps. A hydrogen production plant capacity of 607 tonnes per day was considered. For SMR, based on the percentage of carbon capture and capture points, we considered two scenarios, SMR-52% (indicates 52% carbon capture) and SMR-85% (indicates 85% carbon capture). A scale factor was developed for each technology to understand the hydrogen production cost with a change in production plant size. Hydrogen cost is 1.22, 1.23, 2.12, 1.69, 2.36, 1.66, and 2.55 $/kg H2 for SMR, ATR, NGD, SMR-52%, SMR-85%, ATR with carbon capture and sequestration (ATR-CCS), and NGD with carbon capture and sequestration (NGD-CCS), respectively. The results indicate that when uncertainty is considered, SMR-52% and ATR are economically preferable to NGD and SMR-85%. SMR-52% could outperform ATR-CCS when the natural gas price decreases and the rate of return increases. SMR-85% is the least attractive pathway; however, it could outperform NGD economically when CO2 transportation cost and natural gas price decrease. Hydrogen storage cost significantly impacts the hydrogen production cost. SMR-52%, SMR-85%, ATR-CCS, and NGD-CCS have scale factors of 0.67, 0.68, 0.54, and 0.65, respectively. The hydrogen cost variation with capacity shows that operating SMR-52% and ATR-CCS above hydrogen capacity of 200 tonnes/day is economically attractive. Blue hydrogen from autothermal reforming has the lowest life cycle GHG emissions of 3.91 kgCO2eq/kg H2, followed by blue hydrogen from NGD (4.54 kgCO2eq/kg H2), SMR-85% (6.66 kgCO2eq/kg H2), and SMR-52% (8.20 kgCO2eq/kg H2). The findings of this study are useful for decision-making at various levels.

What do patients want out of their Total Knee Arthroplasty?: An Indian perspective

Introduction and aimTotal Knee Arthroplasty surgery is one of the most successful operations in orthopaedics. Still a sizable percentage of patients remain dissatisfied. Various studies have been conducted to analyse the red flags associated with poor outcome. In this study we tried to have insight on actual requirements of Indian patients from TKA operation. Material & methods300 patients undergoing TKA were studied by way of patient expectation feedback form. The form had various patient related capture points. It had a leading question: What are your expectations from TKA? They were asked to rank the 5 most important options in the order of importance. The patient expectation form was distributed and collected by an independent observer. Results70% of patients ranked relief of pain as the most important expectation. 20% reported improvement in walking as the number one expectation. Nearly equal number listed improvement in walking and ease of doing day-to-day activities as the second most important expectation. This was followed by improvement in climbing the stairs and improvement in quality of life. Correction of deformity and no pain while squatting and getting up from sitting position ranked at the bottom. ConclusionOur study shows that the primary expectations of Indian population from their TKA are relief from pain and improvement in walking. Secondary expectations include ease of doing day-to-day activities and improvement in quality of life.

Spatial distribution and effects of land use and cover on cutaneous leishmaniasis vectors in the municipality of Paracambi, Rio de Janeiro, Brazil

The municipality of Paracambi (Rio de Janeiro, Brazil) reports sporadic cases of American cutaneous leishmaniasis (ACL). Previous studies detected Nyssomyia intermedia (Diptera: Psychodidae) as the main vector in the region, but its spatial distribution and the presence of other vector species have not been evaluated. This study aims at filling this knowledge gap, by studying the ecology of sand flies, their spatiotemporal distribution, and correlation with land use/cover. Two campaigns of monthly sand fly collections using light traps and manual captures were conducted in 1992–1994 and 2001–2003. Females were dissected to detect natural Leishmania infections. The spatial distribution of sand flies was assessed using kernel density maps. Correlations with land use/cover were evaluated by extracting satellite imagery data around the capture points. A total of 17,232 sand flies from 13 species were captured. Medically important species included Ny. intermedia, Migonemyia migonei, Pintomyia fischeri and Ny. whitmani. No Leishmania-infected females were detected. Highest densities were detected in the peri-urban areas Cascata and Sabugo, and in rural areas São José and Mutirão. Ny. intermedia had statistically significant correlations with pasture and agricultural areas. Present results strengthened that Ny. intermedia and Mg. migonei are the main local ACL vectors. Correlations with land use evidence the association between ACL and anthropic environmental change.

Visual quality of Banjir Kanal Timur riverbank as a public open space in the city (Case study: Banjir Kanal Timur Jakarta)

The availability of public open spaces in urban areas is very urgent at this time, especially considering the need for public open spaces that can be used by urban communities, both as social areas and sports recreation. The existing condition along the canal edge requires improving the visual quality so that it can be used as a public open space. The purpose of this study is to evaluate the riverbank, as well as increasing the visual appeal to form public open spaces without reducing the ecological quality of the land and waters of the canal. The analysis method uses scenic beauty estimation, semantic, differential to assess the visual quality at 10 capture points of the coastal riverbank landscape and those with a value less than - 20 have a low or poor visual quality value. In general, the riverbank has a moderate visual quality value because it has not been used properly. The final result of this research activity is as a reference for improving the visual quality of Banjir Kanal Timur, thus creating a Public Open Space according to standart, safe, comfortable regulation for social interaction, sports recreation, education and concern for the ecological and hydrological aspects of the city.

Capture and detumbling control for active debris removal by a dual-arm space robot

Active debris removal (ADR) technology is an effective approach to remediate the proliferation of space debris, which seriously threatens the operational safety of orbital spacecraft. This study aims to design a controller for a dual-arm space robot to capture tumbling debris, including capture control and detumbling control. Typical space debris is considered as a non-cooperative target, which has no specific capture points and unknown dynamic parameters. Compliant clamping control and the adaptive backstepping-based prescribed trajectory tracking control (PTTC) method are proposed in this paper. First, the differential geometry theory is utilized to establish the constraint equations, the dynamic model of the chaser-target system is obtained by applying the Hamilton variational principle, and the compliance clamping controller is further designed to capture the non-cooperative target without contact force feedback. Next, in the post-capture phase, an adaptive backstepping-based PTTC is proposed to detumble the combined spacecraft in the presence of model uncertainties. Finally, numerical simulations are carried out to validate the feasibility of the proposed capture and detumbling control method. Simulation results indicate that the target detumbling achieved by the PTTC method can reduce propellant consumption by up to 24.11%.

Heavy Mineral Assemblage Variation in Late Cenozoic Sediments from the Middle Yangtze River Basin: Insights into Basin Sediment Provenance and Evolution of the Three Gorges Valley

The Three Gorges valley is one of the two key capture points of the evolution of the Yangtze River, yet the formation of this valley—from the pre-Miocene to the late Pleistocene—remains uncertain. The Jianghan Basin, a late Mesozoic–Cenozoic basin located just downstream of the Three Gorges valley, is a crucial area for understanding the formation of the valley. In this study, we used heavy mineral assemblages to trace the provenance of Pliocene–Pleistocene sediments obtained from the 300-m-depth Zhoulao drillcore in the Jianghan Basin. Results show that heavy mineral concentrations, compositions, and species display a clear change at a depth of 110 m in the studied core, consistent with the change in values of magnetic indexes and trace-element geochemical indicators. The heavy mineral assemblage deposited below a depth of 110 m (lower section of the core) comprises zircon, epidote, leucoxene, rutile, anatase, pyrite, and titanite, whereas that deposited above 110 m (upper section) consists of hornblende, pyroxene, garnet, hematite-limonite, and magnetite. In addition, the heavy mineral assemblage of the upper section is similar to that of the modern surface fluvial sediments of the Yangtze, which indicates that materials of the upper core section of the Jianghan Basin were sourced from the upper Yangtze River Basin, west of the Three Gorges. After incision of the Three Gorges valley, sediments from the upper Yangtze were transported to the Jianghan Basin and deposited. Combining the results of this study with the known paleomagnetic chronology of the Jianghan Basin, we propose that the Three Gorges valley was incised at ca. 1.1 Ma.

Controlling messy errors in virtual reconstruction of random sports image capture points for complex systems

When athletes perform different sports, the angles of joints and the speed of movement are different, which causes the feature capture points to not correspond to the key areas well. This results in forming feature messy correspondence errors, and affecting the accuracy of shape basis calculation. The traditional 3D reconstruction algorithms for sports images are affected by the messy profile, and it is difficult to counter the accuracy of later modeling. Therefore, an error control mechanism in the virtual modernization of random sports image collected points is recommended for the complex systems. In this work, the factorization method is used to establish a 3-D dynamic simulation structure of the human body when it is moving. The stolt transformation is implemented for adjusting the azimuth offset rate of all image capturing regions, such that it cannot generate excessive errors during feature matching. The large messy residual error is used for third-order signal compensation for realizing the 3-D dynamic simulation structure in the humanoid signal image sequence. The observed outcomes shows that this approach improves the authenticity of 3-D dynamic simulation of human signal image classifications. Using 150 images and 915 key points, an authenticity coefficient of 0.86 is achieved by the proposed approach outperforming the other state-of-the-art algorithms.