As a water treatment technology combining thermal evaporation and membrane separation, membrane distillation (MD) holds promise for regenerating liquid desiccant and supplying drinking water simultaneously in hybrid a...
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As a water treatment technology combining thermal evaporation and membrane separation, membrane distillation (MD) holds promise for regenerating liquid desiccant and supplying drinking water simultaneously in hybrid air-conditioning systems. The present work aims to compare the potential of two commonly used compact MD configurations, direct contact membrane distillation (DCMD) and air gap membrane distillation (AGMD), for liquid desiccant regeneration under various working conditions. Based on a thermodynamic model, the performance of two solar-driven MD systems are systematically evaluated and compared from an energetic, exergetic and economic perspective. The results show that the AGMD system is preferable at a low operating temperature or solution flow rate compared to the DCMD system in terms of regeneration capacity, energy efficiency and cost-effectiveness. Furthermore, the AGMD system is found to be more competitive in handling highly saline desiccant than the DCMD system since the latter suffers from increasingly remarkable driving force reversal with the rise in concentration. As for the design parameter, the AGMD system exhibits an approximatively linear trend in regeneration capacity with extending membrane length, while for the DCMD system there exists an optimal membrane length at which it can yield the highest regeneration capacity. Additionally, the AGMD system outperforms the DCMD system regarding exergy destruction and exergy efficiency. The seasonal analysis indicates that the availability of DCMD system ranges between 60.7 % and 88.9 % during summer in Hong Kong, lower than that of the AGMD system owing to its less demand for thermal energy. These findings offer valuable insights into suitable selection of MD configurations employed in air-conditioning systems towards sustainable buildings.
Motivated by a class of nonlinear imaging inverse problems, for instance, multispectral computed tomography (MSCT), this paper studies the convergence theory of the nonlinear Kaczmarz method (NKM) for solving the syst...
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Motivated by a class of nonlinear imaging inverse problems, for instance, multispectral computed tomography (MSCT), this paper studies the convergence theory of the nonlinear Kaczmarz method (NKM) for solving the system of nonlinear equations with componentwise convex mapping, namely, the function corresponding to each equation being convex. Such kind of nonlinear mapping may not satisfy the commonly used componentwise tangential cone condition (TCC). For this purpose, we propose a novel condition named relative gradient discrepancy condition (RGDC) and make use of it to prove the convergence and even the convergence rate of the NKM with several general index selection strategies, where these strategies include the cyclic strategy and the maximum residual strategy. Particularly, we investigate the application of the NKM for solving nonlinear systems in MSCT image reconstruction. We prove that the nonlinear mappings in this context fulfill the proposed RGDC rather than the componentwise TCC and provide a global convergence of the NKM based on the previously obtained results. Numerical experiments further illustrate the numerical convergence of the NKM for MSCT image reconstruction.
Loess-mudstone landslides are common in the Loess *** into the mechanical theory of loess-mudstone landslides have become a challenging undertaking due to the distinctive interfacial properties of loess-mudstone and t...
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Loess-mudstone landslides are common in the Loess *** into the mechanical theory of loess-mudstone landslides have become a challenging undertaking due to the distinctive interfacial properties of loess-mudstone and the unique water sensitivity characteristics of ***,it is imperative to develop innovative mechanical models and mathematical equations specifically tailored to loess-mudstone *** this study,we analyze the fracture mechanism of the loess-mudstone sliding zone using plastic fracture mechanics and develop a unique fracture yield *** calculate the energy release rate during the expansion of the loess-mudstone interface tip region,the shear fracture energy G is applied,which reflects both the yield failure criterion and the fracture failure *** better understand the instability mechanism of loess-mudstone landslides,equilibrium equations based on G are established for tractive,compressive,and tensile loess-mudstone *** on the equilibrium equation,the critical length Lc of the sliding zone can be used for the safety evaluation of loess-mudstone *** this way,this study proposes a new method for determining the failure mechanism and equilibrium equation of loessmudstone landslides,which resolves their starting mechanism,mechanical equilibrium equations,and safety evaluation indicators,thus justifying the scientific significance and practical value of this research.
作者：
gao, yuXu, Meng-LeiJilin Agr Univ
Coll Plant Protect Key Lab Soybean Dis & Pest Control Minist Agr & Rural Affairs Changchun Peoples R China Jilin Univ
Coll Food Sci & Engn Jilin Prov Key Lab Nutr & Funct Food Changchun 130062 Peoples R China Jilin Univ
Coll Chem State Key Lab Supramol Struct & Mat Changchun 130012 Peoples R China
Raman spectroscopy is a rapid, noninvasive and sensitive method for analyzing the chemical composition and structure of various sample types. Over the last thirty years, this method has been used widely in entomology,...
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Raman spectroscopy is a rapid, noninvasive and sensitive method for analyzing the chemical composition and structure of various sample types. Over the last thirty years, this method has been used widely in entomology, from insect taxonomy to the detection of pest infestations in plants. This review describes the historical and contemporary applications of Raman spectroscopy in entomology. Researchers have demonstrated their unique advantages in identifying insect species, age and sex. The applicability in detecting agricultural pests has also been well proven. Two particularly promising future applications are: (1) the rapid and precise analysis of chemical and conformational structure;and (2) the detection and identification of insects in agricultural products. Interdisciplinary collaboration between entomologists, chemometricians and spectroscopists is needed to advance the application of this spectroscopic technique and to solve the problem of compositional analysis of complex samples and the determination of unknown components, thus providing a stronger technical basis for the prevention and control of harmful insects.
In this paper, the effect of gamma-ray irradiation on the electrical conductivity of polypropylene (PP) composites has been studied. The samples are prepared using PP and styrene-ethylene-butylene-styrene elastomer wi...
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In this paper, the effect of gamma-ray irradiation on the electrical conductivity of polypropylene (PP) composites has been studied. The samples are prepared using PP and styrene-ethylene-butylene-styrene elastomer with contents ranging from 0 wt% to 50 wt%, and exposed to Cobalt-60 gamma irradiation, with a dose from 0 to 250 kGy. Electrical conductivities at different temperatures and trap distributions are measured to observe the deterioration of insulation performance. The microstructure of the sample is estimated using differential scanning calorimetry, X-ray diffraction, thermogravimetric analysis and a scanning electron microscope. The obtained results demonstrate a correlation between the increase in electrical conductivity and the elevation in both total dose and temperature. At 250 kGy, the trap distribution tends to become shallower, accompanied by a decrease in crystallinity, melting and decomposition temperatures of the sample. The PP composite exhibits better stability against irradiation and thermal effects, primarily due to the cross-linked structures formed by irradiation.
In this work, diffusion diesel flames injected by a single-hole nozzle under different injection pressures and ambient temperatures in a constant volume combustion chamber (CVCC) are reconstructed using three-dimensio...
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In this work, diffusion diesel flames injected by a single-hole nozzle under different injection pressures and ambient temperatures in a constant volume combustion chamber (CVCC) are reconstructed using three-dimensional (3D) computed tomography (CT), representing the first sets of 3D diffusion flame topology within the pressurized combustor. Initially, an optical measurement system comprising fiber bundle endoscopes and high-speed cameras is arranged around the CVCC to capture line-of-sight flame projections from multiple different orientations. Moreover, 3D flames are reconstructed based on the CT technique with enhanced accuracy designed for measuring facilities with restricted optical access. The instantaneous 3D flame topology and its evolution process are analyzed under different injection pressures and ambient temperatures. Compared to two-dimensional analysis, the 3D reconstructions manage to provide in depth investigations on spatial flame intensity evolution, representative turbulent flame patterns, ignition flame kernels merging process and internal void region detection, thereby facilitating a deeper understanding of the combustion process in CVCCs.
This paper uses panel data from 278 prefecture-level cities in China from 2006 to 2021 to examine the relationship between low-carbon city pilot policies and industrial structure upgrading. It is found that China'...
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This paper uses panel data from 278 prefecture-level cities in China from 2006 to 2021 to examine the relationship between low-carbon city pilot policies and industrial structure upgrading. It is found that China's lowcarbon city pilot policy can significantly promote industrial structure upgrading. By enhancing scientific research support and improving the level of urbanization, the low-carbon city pilot policy can promote industrial structure upgrading. Compared to coastal areas in China, the promoting effect of the policy on inland areas is more obvious. The southeastern region shows a stronger promoting effect than the northwestern region. Besides, the impact of the low-carbon pilot policy on industrial structure upgrading has a non-linear characteristic at different carbon emission levels.
A soft actuator converts external energy sources like electricity, light, heat, and humidity into mechanical energy. These actuators are widely used in biomedicine, artificial muscles, electrical switches, and data en...
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A soft actuator converts external energy sources like electricity, light, heat, and humidity into mechanical energy. These actuators are widely used in biomedicine, artificial muscles, electrical switches, and data encryption. MXenes, as two-dimensional materials, provide significant advantages, including high hydrophilicity and excellent photothermal and electrothermal conversion capabilities. However, research on MXene-based actuators has mainly focused on Ti3C2Tx, leaving the potential of other MXene materials underexplored. This study developed V2CTx/PE film-based stimulus-responsive actuators using lamination and cutting techniques, considering the differing thermal expansion and hygroscopic properties of V2CTx and PE films, and examined their electrothermal and photothermal properties. Under a light power density of 70 mW/cm2, the V2CTx/PE film actuator achieved a bending angle of 61 *** application of the V2CTx/PE actuator in smart curtains and crawling machines demonstrates the potential of stimulus-responsive MXene-based composite films for use in smart home technologies and robotics.
High-resolution remote sensing imagery (HRRSI) presents significant challenges for building extraction tasks due to its complex terrain structures, multi-scale features, and rich spectral and geometric information. Tr...
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High-resolution remote sensing imagery (HRRSI) presents significant challenges for building extraction tasks due to its complex terrain structures, multi-scale features, and rich spectral and geometric information. Traditional methods often face limitations in effectively integrating multi-scale features while maintaining a balance between detailed and global semantic information. To address these challenges, this paper proposes an innovative deep learning network, Multi-Source Multi-Scale Residual Attention Network (MMRAD-Net). This model is built upon the classical encoder-decoder framework and introduces two key components: the GCN OA-SWinT Dense Module (GSTDM) and the Res DualAttention Dense Fusion Block (R-DDFB). Additionally, it incorporates Digital Surface Model (DSM) data, presenting a novel feature extraction and fusion strategy. Specifically, the model enhances building extraction accuracy and robustness through hierarchical feature modeling and a refined cross-scale fusion mechanism, while effectively preserving both detail information and global semantic relationships. Furthermore, we propose a Hybrid Loss, which combines Binary Cross-Entropy Loss (BCE Loss), Dice Loss, and an edge-sensitive term to further improve the precision of building edges and foreground reconstruction capabilities. Experiments conducted on the GF-7 and WHU datasets validate the performance of MMRAD-Net, demonstrating its superiority over traditional methods in boundary handling, detail recovery, and adaptability to complex scenes. On the GF-7 Dataset, MMRAD-Net achieved an F1-score of 91.12% and an IoU of 83.01%. On the WHU Building Dataset, the F1-score and IoU were 94.04% and 88.99%, respectively. Ablation studies and transfer learning experiments further confirm the rationality of the model design and its strong generalization ability. These results highlight that innovations in multi-source data fusion, multi-scale feature modeling, and detailed feature fusion mechanisms have
The global climate change and increasing renewable energy demand have fueled research interest in enhancing the capture performance of Wave Energy Converters (WECs) through control mechanisms. In this paper, a latchin...
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The global climate change and increasing renewable energy demand have fueled research interest in enhancing the capture performance of Wave Energy Converters (WECs) through control mechanisms. In this paper, a latching control mechanism is introduced into a coupled linear-bistable WEC system for the first time, to improve the capture performance and broaden the operating bandwidth. Based on the optimal command theory of Pontryagin maximum principle, three latching control strategies are proposed and numerically simulated. The analysis focused on the resonant frequency, capture performance and operational bandwidth of the coupled linear-bistable WEC under these control strategies, and compared the results with the condition without control (WO). Based on this, the impact of control strategies on the capture performance of coupled linear-bistable WEC is systematically compared by the relationship between control forces and floater's motions. The results show that the first-order resonant frequency of the coupled linear-bistable WEC is minimally affected by the control strategies, which significantly enhances capture performance in middle-low and high-frequency regions, leading to a broader operating bandwidth. Among the strategies, the Latching-Coupled Velocity (LCV) strategy exhibits the best control effect, with its effectiveness increasing with wave amplitude. These findings validate the feasibility and effectiveness of the three control strategies and provide valuable insights for integrating latching control mechanisms into complex coupled WEC systems.
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