Search Results (22)

Horizontal well fracturing is a pivotal technology for enhancing the efficiency of shale oil and gas development. Shale reservoirs exhibit significant heterogeneity and intricate fracture propagation patterns, often resulting in uneven multiple fractures caused by horizontal well fracturing. Temporary plugging technology plays a critical role in optimizing fracture propagation patterns; however, there is currently limited research on its optimization. Based on a hydraulic fracturing fracture propagation simulation, an optimization study was conducted on temporary plugging technology for horizontal well fracturing in shale oil reservoirs. Numerical simulation results demonstrate that the uniformity of hydraulic fracture propagation during horizontal well fracturing in shale oil reservoirs is maximized when 30 perforations are plugged. The most uniform fracture propagation pattern is achieved by adding temporary plugging agents after pumping a total volume of 30% fracturing fluid. Furthermore, a comparison between one-time plugging with temporary plugging balls and multiple plugging was made to evaluate differences in fracture propagation. It was observed that performing temporary plugging once significantly improves the uniformity of fracture propagation compared to multiple temporary plugging. These research findings have been successfully validated through the practical application of hydraulic fracturing techniques, as indicated by substantial improvements in both the mode and uniformity of fracture propagation following temporary plugging. Full article

This review comprehensively focuses on catalyst dense-phase packing technology. It provides a systematic review of its principles, characteristics, and applications across diverse fields. A detailed comparison between dense-phase packing and traditional packing methods is presented, along with an in-depth analysis of its application status in petrochemical, fine-chemical, and other industries. The innovative trends of this technology in packing equipment and processes, as well as the challenges and countermeasures in its application, are thoroughly discussed. The aim is to offer a comprehensive and profound reference for relevant research and industrial practices, guiding future development in this crucial area of chemical engineering. Full article

As the global demand for aquafeed ingredients continues to rise, sourcing sustainable alternatives is crucial for aquaculture industries. This study aimed to explore the potential of enzymatic hydrolysate as a substitute for traditional fishmeal and soybean meal in diets for juvenile sea cucumbers (Apostichopus japonicus). Three isonitrogenous (15% crude protein) and isolipidic (2.4% crude lipid) diets were formulated: a control diet containing 10% fishmeal and 5% soybean meal and two experimental low-fishmeal (8%) and low-soybean meal (0%) diets, supplemented with either 8% enzymatically hydrolyzed fish stickwater (EFS) or 8% enzymatically hydrolyzed chicken pulp (ECP), designated as Control, EFS, and ECP, respectively. Juvenile sea cucumbers (initial body weight, 0.25 ± 0.01 g) were fed these diets for 84 days to evaluate the effects of ECP and EFS on their growth performance, antioxidant capacity, and inflammatory responses. The results revealed significantly higher final weights and specific growth rates in both experimental groups than the control (p < 0.05). The proximate chemical compositions of sea cucumber were less affected by the diets (p > 0.05). Compared with the control group, significantly elevated levels of digestive enzymes, antioxidants, and lysozyme, together with lower malondialdehyde levels, were recorded in the experimental groups (p < 0.05). ECP appeared to exhibit greater potency than EFS in enhancing growth performance and antioxidant capacity. Similar trends were observed in the mRNA expression of SOD, CAT, and inflammation-related genes across the groups. In a nutshell, both ECP and EFS supplemented in a low-fishmeal and low-soybean meal diet could effectively promote the growth and health of A. japonicus, with ECP showing a superior effect over EFS. These findings suggest that enzymatic hydrolysate demonstrates potential as a viable alternative to traditional fishmeal and soybean meal in diets for sustainable sea cucumber aquaculture. Further investigations are warranted to reveal its underlying mechanism. Full article

Digital trade (DT), a key component of today’s digital economy, is pivotal in attaining “carbon neutrality and carbon peaking”, essential for low-carbon and high-quality growth. This study delves into the intermediary role of carbon emissions (CE) reduction in DT, analyzing both production and consumption angles, and examines the moderating influences of CE in DT through industrial agglomeration and low-carbon pilot policy. The research employs spatial panel and system GMM models for an empirical investigation. On the production side, the scale and technological effects on CE outweigh the structural impact on emissions. In terms of consumption, the mediating role of urban residents’ consumption upgrading is to enhance the effect of DT on reducing CE by promoting consumption upgrading, whereas the mediating role of rural residents’ consumption upgrading is to promote consumption upgrading but weaken the effect of DT on reducing CE. Regarding regulatory influences, the factor of industrial agglomeration tends to diminish the impact of DT on reducing CE; thus, industrial agglomeration does not amplify the reduction effect of DT on CE. Low-carbon pilot policy(pol)s can enhance the CE reduction effect of DT, showing stronger CE reduction effects in provinces participating in low-carbon pilot programs. Full article

As one of the major water supply systems for inland rivers, especially in arid and semi-arid regions, snow cover strongly affects hydrological cycles. In this study, remote sensing datasets combined with in-situ observation data from a route survey of snow cover were used to investigate the changes in snow cover parameters on the Chinese Altai Mountains from 2000 to 2022, and the responses of snow cover to climate and hydrology were also discussed. The annual snow cover frequency (SCF), snow cover area, snow depth (SD), and snow density were 45.03%, 2.27 × 10⁴ km², 23.4 cm, and ~0.21 g·cm⁻³, respectively. The snow water equivalent ranged from 0.58 km³ to 1.49 km³, with an average of 1.12 km³. Higher and lower SCF were mainly distributed at high elevations and on both sides of the Irtysh river. The maximum and minimum snow cover parameters occurred in the Burqin River Basin and the Lhaster River Basin. In years with high SCF, abnormal westerly airflow was favorable for water vapor transport to the Chinese Altai Mountains, resulting in strong snowfall, and vice versa in years with low SCF. There were significant seasonal differences in the impact of temperature and precipitation on regional SCF changes. The snowmelt runoff ratios were 11.2%, 25.30%, 8.04%, 30.22%, and 11.56% in the Irtysh, Kayit, Haba, Kelan, and Burqin River Basins. Snow meltwater has made a significant contribution to the hydrology of the Chinese Altai Mountains. Full article

An exceptionally high-performance, high-birefringent photonic crystal fiber (PCF) is meticulously designed. The core design features a unique arrangement in which the central row of circular air holes is substituted by three rows of smaller circular holes. Subsequently, the middle row is adjusted to achieve various rectangular mode field configurations. With the optimized structure parameters, the birefringence of the PCF can reach 3.57 × 10${}^{-2}$ at a wavelength of 1.55 $\mathsf{\mu }$m. The confinement loss is as low as 8.4 × 10${}^{-6}$ dB/m. The nonlinear coefficient is up to 41 W${}^{-1}$·km${}^{-1}$. The dispersion is relatively flat within the range from 1.3 $\mathsf{\mu }$m to 1.9 $\mathsf{\mu }$m. These remarkable characteristics render the proposed PCF a strong candidate for applications in polarization preservation, dispersion compensation, wideband supercontinuum generation, and other related fields. Full article

The sustained growth of global meat consumption incentivized the development of the meat substitute industry. However, long-term global commercialization of meat substitutes faces challenges that arise from technological innovation, limited consumer awareness, and an imperfect regulatory environment. Many important questions require urgent answers. This paper presents a review of issues affecting meat substitute manufacturing and marketing, and helps to bridge important gaps which appear in the literature. To date, global research on meat substitutes focuses mainly on technology enhancement, cost reduction, and commercialization with a few studies focused on a regulatory perspective. Furthermore, the studies on meat substitute effects on environmental pollution reduction, safety, and ethical risk perception are particularly important. A review of these trends leads to conclusions which anticipate the development of a much broader market for the meat substitute industry over the long term, the gradual discovery of solutions to technical obstacles, upgraded manufacturing, the persistent perception of ethical risk and its influence on consumer willingness to accept meat substitutes, and the urgent need for constructing an effective meat substitute regulatory system. Full article

Mercury (Hg), as the most potentially hazardous heavy metal, has accumulated in the aquatic environment and has caused concern about its safety. To test the toxic effects of mercury chloride (Hg²⁺) on rare minnow (Gobiocypris rarus), the acute toxicity of Hg²⁺ to embryos, newly hatched larvae, juvenile fish, and the short-term developmental toxicity of Hg²⁺ to the embryo and sac-fry stages, were investigated. The 96-h LC₅₀ values of Hg²⁺ to embryos, newly hatched larvae, and juvenile fish were 0.56, 0.07, and 0.10 mg/L, respectively, suggesting newly hatched larvae were the most sensitive, followed by juvenile fish, while embryos were the most resistant in response to an Hg²⁺ challenge. The research data revealed that the safe level of Hg²⁺ exposure for rare minnow was 0.7 μg/L. In addition, the LOEC (lowest observed effect concentration) and NOEC (no observed effect concentration) values of Hg²⁺ to heartbeat, mortality, malformation rate, and body length of survived larvae were identically, 0.05 and 0.01 mg/L, respectively. These findings indicated that Hg²⁺ had lethal effects on rare minnow at different life stages, and that newly hatched larvae were the most sensitive stage. The above findings have important implications for better understanding the environmental risk assessment of Hg²⁺ on aquatic organisms. Full article

The noise suppression method based on dictionary learning has shown great potential in magnetotelluric (MT) data processing. However, the constraints used in the existing algorithm’s method need to set manually, which significantly limits its application. To solve this problem, we propose a deep learning optimized dictionary learning denoising method. We use a deep convolutional network to learn the characteristic parameters of high-quality MT data independently and then use them as the constraints for dictionary learning so as to achieve fully adaptive sparse decomposition. The method uses unified parameters for all data and completely eliminates subjective bias, which makes it possible to batch-process MT data using sparse decomposition. The processing results of simulated and field data examples show that the new method has good adaptability and can achieve recognition with high accuracy. After processing with our method, the apparent resistivity and phase curves became smoother and more continuous, and the results were validated by the remote reference method. Our method can be an effective alternative method when no remote reference station is set up or the remote reference processing is not effective. Full article

The temperature and pressure of seawater are of great importance to investigate the environmental evolution for the research of ocean science. With this regard, we proposed and experimentally demonstrated a seawater temperature and pressure sensor realized by a polyimide (PI) tube-based Fabry-Perot interferometer (FPI) together with a fiber Bragg grating (FBG). Benefiting from the higher thermo-optical coefficient and larger elasticity of polymer than the fused silica fiber, the sensitivity of the sensor is largely improved. The FBG is used to compensate the cross effect of the temperature. The measured temperature and pressure sensitivities of the sensor are 18.910 nm/°C and −35.605 nm/MPa, respectively. Furthermore, the temperature and pressure information measured by the sensor can be achieved simultaneously using the sensitivity matrix method. In addition, the proposed sensor has advantages of easy fabrication, compact size, as well as capability of multiplexing and long-distance measurement, making it competitive and promising during the marine monitoring. Full article

Glacier mass balance can visually indicate the degree of glacier response to climate change. The mountain glaciers are an essential source of recharge for rivers in arid regions and play a vital role in maintaining regional ecological stability and production life. This paper drives a spatially distributed degree-day model using multi-source remote sensing data such as MOD11C3 and TRMM3B43 to simulate the mass balance in the Tianshan Mountains’ south and north slope basins. The spatiotemporal heterogeneity of the mass balance was compared and attributed using a Geographical detector. The results show that: (1) The glaciers in the north and south basins are mainly distributed at an altitude of 3900–4300 m, and the total glacier area accounts for 85.71%. The number of less than 1 km² glaciers is the most in the whole region. (2) During the study period, the glaciers in the north and south basins were negative (−465.95 mm w.e.) an entire interannual change rate was −28.36 mm w.e./a. The overall trend of ablation can be divided into two stages: from 2000 to 2010a, the persistence increased, and from 2010 to 2016a, the volatility decreased. (3) In the attribution of mass balance, the factors affecting glacier mass balance can be divided into two parts: climate and topography. The cumulative contribution rate of climate factors in Kaidu is nearly 20% higher than that of topographic factors, but the contribution rate of climate factors in Manas is only 7.3% higher. Therefore, the change of glacier mass balance in the Kaidu river basin is more driven by climate factors, while the glacier mass balance in the Manas river basin is more affected by the combination of climate and topographic factors. (4) The climate accumulation is the dominant factor in the Manas river basin (69.55%); for the ablation area, the Kaidu river basin is dominated by climate (70.85%), and the Manas river basin is dominated by topographic factors (54.11%). Due to the driving force of climate and topographic factors and the different coupling modes, glacier mass balance’s spatiotemporal heterogeneity in the north and south slope basins is caused. This study contributes to analyzing the mechanism of regional changes in the glacier mass balance. It provides a scientific basis for investigating the characteristics of water resource changes and water resource regulation in the north and south slope basins of the Tianshan Mountains. Full article

The world’s growing population requires an adequate supply of protein to maintain food security, but animal protein production is limited by the finite resources of land, fresh water, and ocean capacity. Several meat substitutes offer protein alternatives that may improve food security in less-developed economies. However, perceptions of difference in the ethical risk associated with consumption of plant-based substitutes (PM) vs. cultured meat (CM) may affect purchases of these products. This study examined differences in ethical risk perception using online survey data gathered in 2020. An ordered logit technique yielded the probabilities of changes in ethical risk perception influenced by demographic attributes, views about the technology, and adequacy of industry regulations. The results show that consumers associated PM with low ethical risk. Educated consumers were more likely to agree that the ethical risks of CM are higher than PM and to regard PM products as safer than CM. Price sensitivity made consumers more likely to agree that the ethical risks related to CM are higher than those related to PM. Ingredient safety concerns increased the ethical risk perception of CM. Consumers perceiving the meat substitute classification to be unclear were more likely to assign a higher ethical risk to CM than PM. The perception of ethical risk associated with CM was greater than that associated with PM if meat substitute industry regulations were inadequate. The results suggest a need to provide verifiable information about each type of meat substitute as well as transparent and understandable standards and rules before these products can improve protein availability and food security. Full article

Changes in glacier resources and their meltwater runoff contributions in Xinjiang are significant to the hydrological processes and water resources utilization. This study used the first and second Chinese Glacier Inventory, geomorphological and meteorological data. GIS spatial analysis technology was used to explore the characteristics of glacier change and its response to topography and climate change in Xinjiang in the last 50 years. The results show that there are currently 20,695 glaciers in Xinjiang with a total area of 22,742.55 km² and ice reserves of about 2229.17 km³. Glaciers in Xinjiang are concentrated at 5100–6000 m. The Tianshan mountains have the largest number of glaciers. However, the Kunlun mountains have the largest glaciers and ice reserves. The scale of glaciers is significantly larger in the south than that in the north. The changes in glaciers in Xinjiang during the last 50 years are mainly receding and splitting, and their number, area, and ice reserves have decreased by 1359, 7080.12 km² and 482.65 km³, respectively. Small glaciers are more sensitive to climate change. Glaciers are basically unchanged in regions above 6000 m. The glaciers on the south slope of mountains are more susceptible to climate change. The phenomenon of an increase in the number of glaciers but decreasing total area in the southern mountains is related to glacier extinction and splitting. Glacier development and formation are determined by the combination of topography and hydrothermal material conditions. The change of glacier areas in Xinjiang is jointly affected by climatic conditions (53.45%) and topographic conditions (46.55%), among which climatic conditions are more prominent. Full article

The development of “large display, high performance and low cost” in the FPD industry demands glass substrates to be “larger and thinner”. Therefore, the requirements of handling robots are developing in the direction of large scale, high speed, and high precision. This paper presents a novel construction of a glass substrate handling robot, which has a 2.5 m/s travelling speed. It innovatively adopts bionic end-suction technology to grasp the glass substrate more firmly. The structure design is divided into the following three parts: a travel track, a robot body, and an end-effector. The manipulator can be smoothly and rapidly extended by adjusting the transmission ratio of the reducer to 1:2:1, using only one motor to drive two sections of the arm. This robot can transfer two pieces of glass substrate at one time, and improves the working efficiency. The kinematic and dynamic models of the robot are built based on the DH coordinate. Through the positioning accuracy experiment and vibration experiment of the end-effector, it is found that the robot has high precision during handling. The robots developed in this study can be used in large-scale glass substrate handling. Full article

Cadmium (Cd) is a toxic metal and found in various soils, including forest soils. The great spatial heterogeneity in soil Cd makes it difficult to determine its distribution. Both traditional soil surveys and spatial modeling have been used to study the natural distribution of Cd. However, traditional methods are highly labor-intensive and expensive, while modeling is often encumbered by the need to select the proper predictors. In this study, based on intensive soil sampling (385 soil pits plus 64 verification soil pits) in subtropical forests in Yunfu, Guangdong, China, we examined the impacting factors and the possibility of combining existing soil information with digital elevation model (DEM)-derived variables to predict the Cd concentration at different soil depths along the landscape. A well-developed artificial neural network model (ANN), multi-variate analysis, and principal component analysis were used and compared using the same dataset. The results show that soil Cd concentration varied with soil depth and was affected by the top 0–20 cm soil properties, such as soil sand or clay content, and some DEM-related variables (e.g., slope and vertical slope position, varying with depth). The vertical variability in Cd content was found to be correlated with metal contents (e.g., Cu, Zn, Pb, Ni) and Cd contents in the layer immediately above. The selection of candidate predictors differed among different prediction models. The ANN models showed acceptable accuracy (around 30% of predictions have a relative error of less than 10%) and could be used to assess the large-scale Cd impact on environmental quality in the context of intensifying industrialization and climate change, particularly for ecosystem management in this region or other regions with similar conditions. Full article