Search Results (36)

This paper presents a novel dynamic modeling framework for gantry crane systems based on the cart double pendulum with dual cables (CDPD) model. The CDPD model systematically incorporates the effects of dual suspension cables, equalizer beams, and closed-chain kinematic constraints, enabling an accurate simulation of both symmetric and asymmetric lifting scenarios. Utilizing Kane’s method, the model efficiently handles redundant coordinates and holonomic constraints, resulting in a compact and numerically robust formulation. Validation results demonstrate strict energy conservation and consistency with traditional models in limiting cases. The proposed approach provides a unified and extensible foundation for the advanced analysis, control, and optimization of large-scale gantry crane operations. Full article

The incorporation of Mg into PtCoAl catalysts was systematically investigated to elucidate its impact on the physicochemical properties and catalytic performance in CO₂ hydrogenation. A series of x% Mg-PtCoAl catalysts with varying Mg contents were synthesized and evaluated for CO₂ hydrogenation. The results demonstrate that Mg acts as a promoter by strengthening metal–support interactions, slightly suppressing reducibility while markedly enhancing hydrogen adsorption capacity and the number of basic sites. Additionally, an optimal Mg content increases the proportion of weak basic sites, which synergistically facilitates CO₂ activation in conjunction with weakly adsorbed hydrogen. The effects of Pt and Mg loadings were further investigated using different precipitants, revealing that moderate loadings (Pt: 0.11–0.12 mmol g_cat⁻¹, Mg: 0.08–0.10 mmol g_cat⁻¹) most effectively enhance catalytic activity. Under an initial pressure of 4 MPa and 180 °C, the Mg-modified PtCoAl catalyst achieved a methane productivity of 51.4 mmol g_cat⁻¹ h⁻¹ and an alcohol productivity of 0.895 mmol g_cat⁻¹ h⁻¹, with higher alcohols accounting for 33.6% of the total alcohol products. This study underscores the pivotal role of Mg in tuning surface basicity and hydrogen adsorption properties, offering valuable insights for the rational design of efficient CO₂ hydrogenation catalysts. Full article

With the advancement of industrialization and urbanization, the arbitrary emission of sewage containing TC-tetracycline and hexavalent chromium (Cr(VI)) possesses a serious threat to both ecological–environment and public health. However, developing a low-toxicity and cost-effective photocatalyst for the simultaneous elimination of these two pollutants remains a formidable task. This study devised a photocatalytic sample (CSMX-X) comprised of Copper(I) sulfide (Cu₂S) and Titanium carbide (Ti₃C₂) through a simple solvothermal method and applied it to remove TC-tetracycline and Cr(VI). The CSMX-X not only increases the specific surface area from 2.7 m²·g⁻¹ for pure Cu₂S to 30.65 m²·g⁻¹, but also effectively addresses the problems of insufficient separation efficiency of photogenerated holes and electrons and low carrier density. The photocatalytic efficiency for an individual pollutant (10 mg·L⁻¹ Cr(VI) or 20 mg·L⁻¹ TC-tetracycline) can reach more than 90%, while the removal efficiency for mixed Cr(VI) and TC-tetracycline pollutants only decreases by 12%. Meanwhile, copper leaching levels under different pH conditions (0.032–0.676 mg·L⁻¹) are considerably lower than the 2 mg·L⁻¹ safety standard set by the World Health Organization. This study provides valuable perspectives for constructing Cu₂S-based composite photocatalysts to remove multiple contaminants in real aquatic environments. Full article

With the increasing scale of infrastructure projects in sectors such as hydraulics and transportation, coupled with the widespread adoption of anchorage support technologies, numerous rock slope anchorage systems have been established. This study proposes a novel stability evaluation methodology for these systems, integrating genetic algorithms with discrete element analysis. The discrete element method is employed to obtain multi-field data related to the rock slope anchorage system, including slope displacement, pre-stress in anchorage structures, and displacement metrics. The genetic algorithm is utilized for efficient optimization, enabling the identification of numerical model parameters that best align with field monitoring data and actual engineering conditions. Based on the results from discrete element analysis, the proposed method assesses the dynamic variation of multi-field data within the rock slope anchorage system, facilitating a comprehensive stability evaluation. The findings indicate that (1) the proposed evaluation method effectively accounts for the interaction between the anchorage structure and the rock slope, ensuring accurate results; (2) the method leverages the discrete element numerical model to quantitatively assess deformation and stress distribution within the system; (3) the integration of genetic algorithms significantly enhances the efficiency of identifying the most representative numerical model, and thereby the efficiency of stability evaluation is improved; and (4) the evaluation framework is capable of performing dynamic analyses of the stability evolution throughout the entire operational lifecycle of the rock slope anchorage system. Full article

Fluorescent brighteners (FBs) are a class of chemicals extensively used in industrial and consumer products. Their environmental occurrences and potential health risks have raised significant concerns. However, the lack of analytical methods for FBs in human samples has hindered the accurate assessment of internal exposure levels. Addressing this gap, this study developed and validated a novel method for the simultaneous determination of 13 FBs at trace levels in human plasma using solid-phase extraction combined with HPLC-MS/MS. The method employed EMR-Lipid SPE columns, which can selectively adsorb phospholipids for plasma sample pre-treatment. Detection was achieved through positive ion electrospray ionization (ESI) in multiple reaction monitoring (MRM) modes. The results showed that all 13 FBs exhibited good linearity within their respective ranges, with correlation coefficients (R²) greater than 0.992. The method quantitation limits (MQLs) of the FBs ranged from 0.012 to 0.348 ng/mL, and the spiked recovery rates ranged from 61% to 98%. The method was successfully applied to analyze 10 adult plasma samples, detecting 10 FBs with total concentrations ranging from 0.221 to 0.684 ng/mL. This study provides a reliable analytical method for determining FBs in human plasma, providing a basis for further research on human internal exposure to FBs and associated health risk assessments. Full article

The restorative effects of various environmental factors within urban forests on physical and mental health exhibit significant differences. Specifically, vegetation types and topographical slope positions are key elements contributing to the environmental heterogeneity of urban forests. However, there is a lack of studies that have concurrently examined the health restoration effects of both factors. This study conducted an empirical experiment on university students in urban forests during the autumn season, investigating the effects of different vegetation types and slope positions on physiological and psychological restoration, and identifying the key environmental factors contributing to these effects. The results show the following: (1) Urban forests with different vegetation types exhibit varying restorative effects, with coniferous forests offering greater physiological restoration benefits than coniferous–broadleaf mixed forests. (2) Slope position affects both physiological and psychological restoration. In coniferous forests, the restorative effects on physical and mental health are greater at the top and midslope positions compared to the bottom slope position; in coniferous–broadleaf mixed forests, the best physiological restoration effects occur at the midslope position. (3) The key environmental factors influencing physiological restoration in urban coniferous forests are panoramic green coverage and elevation. (4) In urban coniferous–broadleaf mixed forests, temperature, humidity, and wind speed are the key factors affecting physiological restoration. This study reveals the restorative differences in urban forests under different vegetation types and slope positions, identifies the key environmental factors influencing health restoration, and provides a theoretical basis for further research on the impact of urban forests on human health. Future urban forest layout and design should fully consider the characteristics of different slope positions, optimize microclimate regulation, and maximize their role in promoting public health. Full article

The low-altitude economy heavily relies on new carriers represented by unmanned aerial vehicles (UAVs). The localization accuracy of UAVs highly relies on the Global Navigation Satellite System (GNSS), which can be easily affected in low-altitude urban environments, making it difficult to maintain effective localization accuracy. To solve this problem, this paper proposes a UAV autonomous localization method with keypoints on the edges of semantic objects (KESO). Firstly, semantic objects within the working area are selected, and then the latitude, longitude, and altitude of these semantic objects’ keypoints are measured to construct a database. By identifying the semantic objects from aerial images and detecting the edge of the semantic objects, the keypoints of the semantic objects are obtained. Finally, by matching the detected keypoints in the aerial images with the keypoints in the database, the UAV’s position can achieve a high-precision position when satellite signals are blocked in low-altitude urban environments. As verified by real flight data, the results show that the localization error is less than 5 m, and the edges of objects can obtain more accurate keypoints to help UAVs locate more accurately. This paper can provide a reference for UAV localization in the urban environments of the low-altitude economy. Full article

As a byproduct of corn processing, corn husk is usually burned or disposed of. To make a better use of corn husk, its bioactive components need to be further explored. In this work, the carotenoids and phenolics of the extracts from the corn grain and corn husk of 15 different yellow corn and 8 different waxy corn were identified and quantified, and their antioxidant activities were assessed. The results showed many considerable variations in carotenoid contents. Four types of carotenoids were observed only in both yellow corn and black waxy corn. The highest lutein and zeaxanthin contents were both observed in yellow corn husks. Lutein dominates in yellow corn, ranging from 494.5 μg/g dw to 2870.8 μg/g dw, which is followed by zeaxanthin, ranging from 63.0 μg/g dw to 360.2 μg/g dw, and finally β-cryptoxanthin and β-carotene. The total content of polyphenols (TPC) and flavonoids (TFC) of the husk from 13 yellow corn cultivars, as well as the TPC of husk from 8 waxy corn cultivars, were all higher than those of their corn grain, with the highest TPC found in waxy corn husk. Additionally, a total of 20 phenolic compounds were identified, and ferulic acid showed the highest content and reached 1101.9 µg/g dw in a waxy corn husk. The average antioxidant activity of a waxy corn husk was 25–65% higher than that of a yellow corn husk, and the highest values were observed in the husk of the waxy corn cultivar Huhong 1. These results suggested that corn husk is a rich source of lutein and phenolics and provided excellent cultivars as a reference for functional food products in agriculture and the food industry. Full article

We have developed an ovarian cancer-targeted drug delivery system based on a follicle-stimulating hormone receptor (FSHR) peptide. The lipophilic chemotherapeutic drug SN38 and the photosensitizer IR820 were loaded into the phospholipid bilayer of liposomes. The combination of chemotherapy and phototherapy has become a promising strategy to improve the therapeutic effect of chemotherapy drugs on solid tumors. IR820 can be used for photodynamic therapy (PDT), effectively converting near-infrared light (NIR) into heat and producing reactive oxygen species (ROS), causing damage to intracellular components and leading to cell death. In addition, PDT generates heat in near-infrared, thereby enhancing the sensitivity of tumors to chemotherapy drugs. FSH liposomes loaded with SN38 and IR820 (SN38/IR820-Lipo@FSH) were prepared using thin-film hydration-sonication. FSH peptide binding was analyzed using 1H NMR spectrum and Maldi-Tof. The average size and zeta potential of SN38/IR820-Lipo@FSH were 105.1 ± 1.15 nm (PDI: 0.204 ± 0.03) and −27.8 ± 0.42 mV, respectively. The encapsulation efficiency of SN38 and IR820 in SN38/IR820-Lipo@FSH liposomes were 90.2% and 91.5%, respectively, and their release was slow in vitro. FSH significantly increased the uptake of liposomes, inhibited cell proliferation, and induced apoptosis in A2780 cells. Moreover, SN38/IR820-Lipo@FSH exhibited better tumor-targeting ability and anti-ovarian cancer activity in vivo when compared with non-targeted SN38/IR820-Lipo. The combination of chemotherapy and photodynamic treatment based on an FSH peptide-targeted delivery system may be an effective approach to treating ovarian cancer. Full article

With the increasing popularity of automatic identification system AIS devices, mining latent vessel motion patterns from AIS data has become a hot topic in water transportation research. Trajectory similarity computation is a fundamental issue to many maritime applications such as trajectory clustering, prediction, and anomaly detection. However, current non-learning-based methods face performance and efficiency issues, while learning-based methods are limited by the lack of labeled sample and explicit spatial modeling, making it difficult to achieve optimal performance. To address the above issues, we propose CLAIS, a contrastive learning framework for graph-based vessel trajectory similarity computation. A combined parameterized trajectory augmentation scheme is proposed to generate similar trajectory sample pairs and a constructed spatial graph of the study region is pretrained to help model the input trajectory graph. A graph neural network encoder is used to extract spatial dependency from the trajectory graph to learn better trajectory representations. Finally, a contrastive loss function is used to train the model in an unsupervised manner. We also propose an improved experiment and three related metrics and conduct extensive experiments to evaluate the performance of the proposed framework. The results validate the efficacy of the proposed framework in trajectory similarity calculation. Full article

In 1960, R.E. Kalman published his famous paper describing a recursive solution, the Kalman filter, to the discrete-data linear filtering problem. In the following decades, thanks to the continuous progress of numerical computing, as well as the increasing demand for weather prediction, target tracking, and many other problems, the Kalman filter has gradually become one of the most important tools in science and engineering. With the continuous improvement of its theory, the Kalman filter and its derivative algorithms have become one of the core algorithms in optimal estimation. This paper attempts to systematically collect and sort out the basic principles of the Kalman filter and some of its important derivative algorithms (mainly including the Extended Kalman filter (EKF), the Unscented Kalman filter (UKF), the Ensemble Kalman filter (EnKF)), as well as the scope of their application, and also to compare their advantages and limitations. In addition, because there are a large number of applications based on the Kalman filter in data assimilation, this paper also provides examples and classifies the applications of both the Kalman filter and its derivative algorithms in the field of data assimilation. Full article

A keloid is a benign tumor manifested as abnormal fibroplasia on the surface of the skin. Curing keloids has become a major clinical challenge, and searching for new treatments and medications has become critical. In this study, we developed a LA67 liposome-loaded thermo-sensitive hydrogel (LA67-RL-Gel) with active targeting for treating keloids via peritumoral injection and explored the anti-keloid mechanism. Firstly, Arg-Gly-Asp (RGD) peptide-modified liposomes (LA67-RL) loaded with LA67 were prepared with a particle size of 105.9 nm and a Zeta potential of −27.4 mV, and an encapsulation efficiency of 89.6 ± 3.7%. We then constructed a thermo-sensitive hydrogel loaded with LA67-RL by poloxamer 407 and 188. The formulation was optimized through the Box–Behnken design, where the impact of the proportion of the ingredients on the quality of the hydrogel was evaluated entirely. The optimal formulation was 20.7% P407 and 2.1% P188, and the gelation time at 37 °C was 9.5 s. LA67-RL-Gel slowly released 92.2 ± 0.8% of LA67 at pH 6.5 PBS for 72 h. LA67-RL-Gel increased adhesion with KF cells; increased uptake; promoted KF cells apoptosis; inhibited cell proliferation; reduced α-SMA content; decreased collagen I, collagen III, and fibronectin deposition; inhibited angiogenesis; and modulated the keloid microenvironment, ultimately exerting anti-keloid effects. In summary, this simple, low-cost, and highly effective anti-keloid liposome hydrogel provides a novel approach for treating keloids and deserves further development. Full article

In recent years, steel fiber-reinforced concrete (SFRC) single-layer linings have been used in tunnel engineering. Compared to plain concrete single-layer linings, SFRC single-layer linings demonstrate enhanced bearing capacity, durability, and sustainability. Existing studies primarily focused on the mechanical properties of SFRC; however, limited investigations have been conducted on the cracking pattern of SFRC linings. This study uses laboratory tests to examine the influence of steel fiber content and aspect ratio on the mechanical properties of concrete, such as compressive strength and elastic modulus. After the recommended content and aspect ratio of steel fiber are proposed through tests, the cracking pattern and safety performance of plain concrete and SFRC linings under surrounding rock pressure are studied using a similar model test. The test results indicate that the recommended steel fiber volume fraction and aspect ratio for CF35 SFRC are 0.58% and 70, respectively. Due to the effect of loose load, cracks initially develop on the inside of arch crowns in both plain concrete and SFRC single-layer linings. Subsequently, new cracks appear on the inside of the lining floor and the outside of the two wall feet. Numerous narrow cracks with rugged and winding expansion paths can be found on SFRC single-layer linings. Conversely, plain concrete single-layer linings exhibit fewer cracks with larger widths along a straighter path. The initial cracking load of a single-layer lining made of plain concrete is 0.027 MPa, whereas for a single-layer lining made of SFRC, it is 0.04 MPa. This indicates that SFRC can effectively enhance the initial cracking load of lining structures. In the event of damage to the lining, the most critical area for the plain concrete single-layer lining is at the two wall feet, where the minimum safety factor is 1.66. However, for the SFRC lining in the same location, the safety factor is 2.7, resulting in a 62.7% increase in safety. Full article

Masonry is among the most widely used construction materials around the world. Contemporary masonry buildings are primarily designed to comply with prescriptive building code regulations. In recent decades, performance-based design (PBD) has gained increasing attention and achieved significant success in critical structures or infrastructure systems. Instead of being the first mover, the masonry research and practice community can be a faster follower in response to the design paradigm shift towards PBD for masonry buildings. A reliable performance assessment of masonry buildings is of paramount importance in the PBD framework. To facilitate this, this paper presents an up-to-date comprehensive literature review of experimental and analytical studies with emphasis on their contributions to advancement towards performance assessment of masonry buildings. This review categorized available works into two sub-topics: (1) traditional unreinforced masonry and (2) modern reinforced masonry. In each sub-topic, studies focusing on the structural behaviors of masonry at the component-level (i.e., masonry wall) are discussed first, followed by the building system-level-related studies. Through this literature review, the current state of the art and remaining research gaps are identified to provide guidance for future research needs and to pave the way for implementing PBD in the masonry industry. Full article

The study of wearable systems based on surface electromyography (sEMG) signals has attracted widespread attention and plays an important role in human–computer interaction, physiological state monitoring, and other fields. Traditional sEMG signal acquisition systems are primarily targeted at body parts that are not in line with daily wearing habits, such as the arms, legs, and face. In addition, some systems rely on wired connections, which impacts their flexibility and user-friendliness. This paper presents a novel wrist-worn system with four sEMG acquisition channels and a high common-mode rejection ratio (CMRR) greater than 120 dB. The circuit has an overall gain of 2492 V/V and a bandwidth of 15~500 Hz. It is fabricated using flexible circuit technologies and is encapsulated in a soft skin-friendly silicone gel. The system acquires sEMG signals at a sampling rate of over 2000 Hz with a 16-bit resolution and transmits data to a smart device via low-power Bluetooth. Muscle fatigue detection and four-class gesture recognition experiments (accuracy greater than 95%) were conducted to validate its practicality. The system has potential applications in natural and intuitive human–computer interaction and physiological state monitoring. Full article