bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on the uniformity of internal flow field of air knife
Authors: Chen Hui , Lai Huanxin
Published: October 2024

The uniformity of the flow in the air knives play a crucial role for the quality of the galvanized anti-corrosion coating. Simulations of the flow are carried out to study the uniformity. To simplify the simulations, the air knife is segmented into two parts: the ends- and the periodic-segments. The velocity, vorticity, and turbulent kinetic energy both around the air distribution plates and the outlet are analyzed. Results show that the uniformity in downstream of the air distribution plates is higher in the periodic segment than that in the ends segment. While the uniformity around the outlet is found similar in the ends- and the periodic- segments. When the opening degree of the knife lip decreasing, the uniformity increases in downstream of the air distribution plates and decreases around the outlet. In such way, the present study sheds some light for the internal flow field of the air knife, and provides technical support for the design of air knife.
The Wind Power Blade Spoiler Design and Validation Based on CFD
Authors: Yujun Qiao , Zhenya Fan , Wenming Zhou , Yongguo Feng
Published: October 2024

The power generation capacity of the wind turbine is derived from the aerodynamic properties of the blade, which can be characterized by the local flow state of the blade. In order to improve the aerodynamic performance of the blade and furthermore the power generation efficiency of the wind turbine, the top priority is to find the abnormal area of the local flow along the blade, and take relevant strategies to control the abnormal flow. The CFD-based blade spoiler design is carried out in both the blade root and the blade middlepiece respectively. Meanwhile, the influence of assembled spoilers on the local and whole performance of the blade is verified by the panel method and BEM method. The verification lays the foundation for further flow control optimization design.
Numerical Simulation and Artificial Neural Network Modeling of Cavitation on 2D Tandem Hydrofoils Arrangement
Authors: Gang Yin , Yiteng Zhao , Guidong Li
Published: October 2024

In the current research, we used a parametric approach to investigate cavitation with tandem-arranged Clark Y-11.7% hydrofoils. We simulated the tandem-arranged hydrofoil system using ANSYS FLUENT with the Zwart cavitation model combined with the Transition SST turbulence model. To substantiate the accuracy and reliability of the numerical model, computations were performed for an individual Clark Y-11.7% hydrofoil and compared to experimental results. The following parameters were studied in tandem arrangement: cavitation number(σ), horizontal direction spacing ratio between two hydrofoils(x), vertical direction spacing ratio between two hydrofoils(y), angle of attack (AOA) of the upstream hydrofoil (α
1), and angle of the downstream hydrofoil relative to the upstream hydrofoil (α
2). The lift coefficient (C
L) was used to estimate due to the acceptable error. An optimal artificial neural network (ANN) model was trained based on the five-parameter combination from numerical simulations. The model’s weights and biases were presented, providing a prediction method for hydrofoils in tandem arrangement with cavitation. A global sensitivity analysis based on the trained model is implemented, which reveals the AOA of the downstream hydrofoil (α
2), the horizontal spacing ratio (x), and the AOA of the upstream hydrofoil (α
1) have a main effect on the performance of the tandem arrangement.
Optimized design of annular ejector primary nozzle based on orthogonal test method
Authors: Liu Kang , Guan Xifeng , Fang Kaiyue , Cao Zhengqing , Zhang Xinchen , Yang Xuelong
Published: October 2024

Annular ejectors are widely used in aerospace and other applications, and their performance has a significant impact on the overall system. In this paper, the effects of main nozzle area ratio, contraction section angle and diffusion section angle on the performance of annular ejector are investigated by using computational fluid dynamics combined with one-factor experiments, on the basis of which the L9(33) orthogonal table is established to optimise the structure of main nozzle and to screen the main influencing factors. The results show that the flow field inside the annular ejector is extremely complex. The influence of the main nozzle area ratio on the performance of the annular ejector is very great, and the change of the area ratio will lead to the change of the position of the second excitation sequence as well as the Mach number at the outlet of the main nozzle. However, as with the results of the one-way analysis, the effect of the angle of the constriction section on the exit Mach number is negligible.
SSM-CloudNet: state space model-based cloud and cloud shadow detection network for Sentinel-2 imagery
Authors: He Lirong , Pu Pengyu , Zhang Ying , Xu Meng
Published: October 2024

Remote sensing images acquired by satellite sensors are inevitably obscured by clouds and cloud shadows, which obscure true ground reflectance information in those areas. Therefore, to ensure the accuracy and reliability of downstream analyses, detecting clouds and their shadows in satellite images is crucial. This paper proposes a state space model-based cloud and cloud shadow detection network for Sentinel-2 imagery, named SSM-CloudNet. This is the first time that a state space model (SSM) is applied to cloud and cloud shadow detection tasks, combining the efficient feature extraction capability of the symmetric encoder-decoder structure with the accuracy of SSM in cloud feature extraction, and providing an innovative approach to this task. Experiments demonstrate that SSM-CloudNet performs exceptionally well across multiple metrics, proving the high effectiveness of the proposed method.
Research on 3D geographic entity recognition method based on the double matching degree
Authors: Zhang Huabin , Liao Shunhua , Bai Haoyuan , Yang Xincheng
Published: October 2024

In the process of real-view 3D construction, the description of the same geospatial object by multiple departments is not the same, and how to link the city’s multi-source datasets to the same entity and construct the mapping relationship between multi-source data has become the current difficulty of multi-source data convergence. A double-matching degree entity recognition method was proposed in this paper for the problem of unified geographic entities in data convergence. Firstly, the address information is extracted from the original address data according to the address elements, and the hierarchical address tree is established by using the organization of a dictionary tree for hierarchical matching. The BERT model and twin neural network are introduced to divide the address information on the remaining paths at the byte and word level to calculate the similarity of address information. Then, the similarity of entity names is calculated by the method based on editing distance, and by combining the string-based method and the neural network-based method with each other, the hierarchical step-by-step matching is performed to narrow the matching space, determine the matching entities, and establish the entity links. Experiments on the self-built dataset show that this method has performed better in entity recognition compared to other methods.
Analysis of evolutionary paths and application scenarios of InSAR in geohazard research
Authors: Zhang Jiarui , Geng Wei , Dai Xiaomin , Song Liang
Published: October 2024

With the deterioration of the world environment and intense human activities, geohazards show a frequent occurrence, and InSAR, with its all-weather, all-day, and penetrating nature, rapidly develops into an essential means of earth monitoring. In this paper, using Citespace knowledge graph analysis software, we combed the CNKI core database from 2004 to 2023 and the literature about InSAR in geohazards. The evolution path was analyzed through the spatiotemporal evolution mapping and keyword co-occurrence network parsing, and the research trends and hotspots were predicted. The research results show that firstly, the application of InSAR in geohazards has experienced three classic stages: emerging development, early identification, and synergistic monitoring; secondly, the research topics were clustered into three main spatial and temporal evolution paths, which were “geohazard,” “phase disentanglement”, and “genetic algorithm”; thirdly, future perspectives of InSAR-based technology for geohazard monitoring mainly include as “efficient and intelligent monitoring” and “digital multidimensional monitoring”.
Research on AIS algorithm based on factor graph inference in Doppler localization
Authors: Chen Wantong , Xu Jiale , Liu Ruihua , Sun Shuguang
Published: October 2024

In this paper, an adaptive incremental smoothing (AIS) algorithm based on factor graph inference is proposed to solve the problem of improving the Doppler positioning accuracy of low-Earth orbit communication satellites. Traditional methods such as iterative least squares (ILS) algorithm and Extended Kalman filter (EKF) have certain limitations in real-time Doppler localization. The AIS algorithm uses factor graph inference to identify interference factors, and adopts adaptive smoothing to reduce the impact of estimation errors and promote adaptive noise estimation. The ground station Starlink satellite constellation static positioning was taken as an example, and the simulation was carried out on the STK software simulation platform to verify the feasibility and effectiveness of the algorithm. The experimental results show that the positioning accuracy of the AIS algorithm based on factor graph inference is significantly improved compared with the ILS and EKF algorithms in real-time Doppler positioning solutions. The aim of this research is to improve the positioning accuracy of low-orbit satellites and provide a reference for practical applications.
Current Progress of EUV Spectral Responsivity Calibration for EUV Lithography at CMS/ITRI
Authors: Chuang Yi-Chen , Chen Cheng-Hsien
Published: October 2024

To support the development of advanced EUV lithography for the semiconductor industry in Taiwan, a calibration system for photodiodes’ spectral responsivity was established. The current system utilizes the synchrotron radiation light source and the method is traceable to PTB, Germany. The wavelength range is from 10 nm to 15 nm, including the most often used 13.5 nm. Several techniques were studied to compensate for light source fluctuation and to reduce the measurement uncertainty. The relative expanded uncertainty of the spectral responsivity calibration at 13.5 nm is 4.6 % (k=2). A wafer-type EUV radiant power meter designed to be used in EUV lithography chambers is being developed. Our goal is to develop simple and reliable methods for on-site EUV optical power measurement and dose estimation.
A Portable Broadband Radiance Source for Ground Validation Sites
Authors: Li L , Sun R , Wang Y , Wu Z , Dai C
Published: October 2024

A portable broadband radiance source based on COB-LED has been developed. It was designed to calibrate array spectroradiometers for Ground Validation Sites. The spectral distribution of COB-LED chip was more similar with solar radiance than traditional calibration light source in the wavelength range between 380 nm and 780 nm. The spectral radiance stability of the light source measured under laboratory condition was within 0.1%/h by developing the temperature control system and high-precision portable power supply. The COB-LED-based source was calibrated by Spectral Irradiance Secondary Standard at NIM.
New Mie Scattering Diffuse Targets Development and Characterization
Authors: Georgiev Georgi , McCorkel Joel , Barsi Julia , Patel Jessica , Gao Guangjun , Georgieva Elena
Published: October 2024

Earth science remote sensing observations require the detection and measurement of light originating from bright targets, such as clouds, and darker targets, such as an open ocean. This requirement drives the need to design, develop, and characterize improved calibration targets in support of current and future NASA instruments. New diffuse targets to be used as spectral albedo calibration standards were developed and characterized. The new targets based on fused silica or/and pressed and sintered Polytetrafluoroethylene (PTFE) were developed to be Earth scene specific. The various reflectance levels are achieved by modifying the material parameters, thickness, and surface finish. The new targets were characterized in cleanroom environment. We acquired high accuracy reflectance and transmittance data using a precision optical scatterometer and spectrophotometer located in the NASA Goddard Space Flight Center (GSFC) Diffuser Calibration Lab. The Total hemispherical reflectance (THR) and Bidirectional Reflectance Distribution Function (BRDF) were measured over the range of solar incident and scattered elevation and azimuthal angles typically realized on orbit by remote sensing instruments. We intend to space certify the new calibration targets after concluding on-orbit testing on the International Space Stations (ISS) scheduled for the second half of 2023.
Using the MSL goniospectrophotometer to measure the bidirectional transmittance distribution function
Authors: Molloy E , Koo A
Published: October 2024

Measurements of the bidirectional transmittance distribution function (BTDF) are of interest to a wide range of industries, including satellite calibration, computer graphics, and lighting design. The scale of BTDF is realised at various national metrology institutes using goniospectrophotometers. This paper describes the measurement model for BTDF using the MSL goniospectrophotometer, which uses rotation stages to adjust the angle of the sample. The measurement model is applied to measurements of two different sample types as an example of the performance of the instrument.
Design and development of a portable tuneable radiation source from UV to IR for in situ calibration of radiometers measuring atmospheric aerosol properties.
Authors: Smid M , Porrovecchio G , Burnitt T , Tesar J , Linduska P
Published: October 2024

We present the results of development of a portable tuneable radiation source (TuPS II) covering the broad spectral range from 300 nm up to 1700 nm. It was developed to provide SI-traceable in-situ calibration of bandpass functions of radiometers measuring both sky radiance and sky irradiance in the surface-based remote sensing networks for column integrated atmospheric aerosol properties. The TuPS II provides quasi-monochromatic radiation with spectral bandwidth smaller than 0.2 nm and central wavelength uncertainty lower than 0.05 nm for a specified number of aerosol wavelength bands ranging from to 300 nm to 1700 nm. In its design it represents an evolution with extended spectral capabilities of the TuPS (Smid, M. et al., 2021) that was successfully used to characterize Dobson spectrophotometers in the UV spectral range.
Study on welding process of stainless steel/superalloy dissimilar materials
Authors: Liu Xin , Li Zhuoliang , Yu Xianglin , Zhang Quanhou , Wang Jibing , Guan Changjiang , Wang Jun
Published: October 2024

In this study, dissimilar materials of 321 stainless steel, S-03 stainless steel, and GH3030 superalloy were selected and the argon tungsten-arc welding method was used to explore the welding parameters. The microstructure and properties of three materials after welding were studied. The main mechanism of welding cracks was analyzed by optical microscope and scanning electron microscope. Reasonable welding parameters were established and the dissimilar welding process was realized. The experimental results show that the cracks produced by welding of the three materials are typical welding hot cracks. The crack source originated from the bottom layer and extended to the surface of the welded joint. The main reason for cracking is the formation of low melting point compounds by the segregation of S and Ti elements during the process of self-melting. The welding process of the dissimilar materials can be realized by multi-pass filling welding. Increasing welding speed and reducing heat input are effective ways to improve weld mechanical properties of the welded joint.
Effects of processing parameters on microstructure and mechanical properties of friction stir additive manufactured Al-Zn-Mg-Cu alloy
Authors: Li Ying , Li Xiwu , He Changshu , Wen Kai , Li Yanan , Yan Lizhen , Zhang Yongan , Xiong Baiqing
Published: October 2024

A multilayered build was fabricated by friction stir additive manufacturing (FSAM) with different parameters, using 4-mm thick 7A04-T6 aluminum alloy sheets in this study. The parameters effect on the microstructure and mechanical properties of the builds were investigated combined scanning electron microscopy (SEM), transmission electron microscopy (TEM), vickers hardness and tensile tests. Macro-softening phenomenon was observed in the builds. The precipitation and growth of the Mg (Zn, Cu, Al)2 or MgZn2 phase with the effect of the effective thermal cycles during the FSAM process mainly attributed to the formation of the macro-softening. The more effective thermal cycles experienced during the FSAM process, the more Mg (Zn, Cu, Al)2 or MgZn2 phase precipitated and coarsened, resulting in a more pronounced decrease in the mechanical properties of the build. Heat input affected the macro-softening behavior of the build by influencing the degree of dissolution, re-precipitation and coarsening of the precipitates during the FSAM process. Too low or too high heat input resulted in the incomplete dissolution or further precipitation and growth of the precipitates, aggravating the macro-softening phenomenon, and reducing the precipitation strengthening ability of the build. The mechanical properties of the build fabricated at the rotation speed of 700 rpm and travelling speed of 160 mm/min were the best in this study.
Core-Shell catalyst-mediated hydrodeoxygenation of guaiacol for the preparation of cyclohexanol
Authors: Luan Guili , Nie Genkuo
Published: October 2024

The conversion of lignin-derived phenolic compounds into high-value chemicals through value-added reactions holds significant importance. Cyclohexanol, an essential chemical raw material and organic intermediate, was synthesized in this study from guaiacol, a phenolic compound derived from lignin, through a hydrodeoxygenation reaction. When compared to mechanically mixed and supported catalysts, the use of the HZSM-5@Pd-SiO2 core-shell catalyst resulted in a cyclohexanol yield of 51.1% after a reaction conducted at 493K and 2 MPa H2 for 8h. The core-shell catalyst was characterized using TEM, N2 adsorption-desorption, and NH3-TPD, Py-FTIR revealing its rich acid sites, large specific surface area, and uniform mesopores.
Preparation and study of polyvinylidene fluoride film with high UV aging resistance
Authors: Wang Peng , Nie Fu , Fei Hailin , Zhen Wanqing
Published: October 2024

Polyvinylidene fluoride materials were widely used in the preparation of solar panel films due to their excellent weather resistance and heat resistance. In this work, Polyvinylidene fluoride films with UV absorbers (PF/UV films) were prepared by customized extrusion equipment. The properties of these films were demonstrated with a scanning electron microscope (SEM), water contact angle (WCA), thermogravimetric analyzer (TGA), differential scanning calorimetry (DSC), and tensile strength tester. Furthermore, the SEM observation suggested that PF/UV films had smooth surfaces without significant defects. The WCA results illustrated that PF/UV films had better hydrophobicity than polyvinylidene fluoride films. The TGA and DSC curves indicated that the initial decomposition temperature and the melting temperature of the PF/UV film were 365.1°C and 169.2°C, respectively. Furthermore, the results of UV transmittance indicated that the UV aging resistances of PF/UV film were higher than that of polyvinylidene fluoride film.
Study on the mechanical properties of non-calcined coal gangue geopolymer concrete reinforced by basalt fibers
Authors: Pu Xinmeng , Chen Yijie , Chen Yilun
Published: October 2024

Fiber-reinforced non-calcined coal gangue-based polymer concrete (BFCGGC) was synthesized utilizing gangue, slag, an alkali exciter solution, and coarse and fine aggregates, alongside basalt fibers as primary constituents. Mechanical characteristics of BFCGGC were investigated by varying the mass fractions of basalt fibers, while its micro-mechanism was examined using scanning electron microscopy. The findings indicated a trend in the compressive strength of BFCGGC, initially ascending and subsequently descending with fiber incorporation. Nevertheless, both tensile and flexural strengths exhibited continuous augmentation with the inclusion of fibers. Notably, basalt fibers demonstrated a pronounced improvement in the split tensile strength of BFCGGC, with a peak enhancement rate reaching 41.3%.
Effect of dimensional stabilization treatment on mechanical properties of 45% SiCp/Al composites
Authors: Dai Tong
Published: October 2024

With 14μm SiC particles and 2024Al alloy as raw materials, 45% SiCp/Al composites were prepared by hot isostatic pressing method to study the effect of dimensional stabilization treatments on the mechanical properties of composites. The dimensional stabilization treatments used were divided into annealing heat treatment and cold and thermal cycle treatments, and the research method found that the primary annealing treatment decreased the bending strength from 694MPa to 639MPa, and the secondary annealing treatment decreased the bending strength from 863.69MPa to 605MPa. The bending strength decreased from 694 MPa to 639 MPa after the second annealing treatment, and further to 605 MPa after the second annealing treatment. The bending strength of the composites also decreased from 863.69 MPa to 836.16 MPa, and then to 855.54 MPa after solution aging due to the cold and thermal cycle treatments of 120°C to −20°C and 190°C to −196°C, respectively. The micro yield strength increased from 356.57 MPa to 402.66 MPa, and then to 476.03 MPa. The dimensional stabilization treatments included heat treatment, as well as cold and thermal cycle treatments. The cold and thermal cycle treatments further increased the brittleness of the composites after solution aging. Both annealing and cold and thermal cycling reduce the density of the composite, with the annealing resulting in a smaller reduction than the cold and thermal cycling.
Citric acid induced enhancement in capacitive performances of polyaniline/graphene gel electrode for flexible supercapacitors
Authors: Dong Jiahui , Qin Zongyi
Published: October 2024

A composite hydrogel electrode for a flexible supercapacitor was fabricated by dispersing polyaniline/graphene composite into a polyvinyl alcohol gel network in the presence of citric acid. It was found that the introduction of citric acid could greatly promote the capacitive performances of composite gel electrodes. The assembled flexible supercapacitor could exhibit a maximum specific capacitance of 321.3 F g−1 at 1 A g−1 with a capacitance retention rate of 76.0% (from 1 A g−1 to 20 A g−1). Furthermore, even after enduring 5000 cycles at 20 A g−1, the supercapacitor maintained 86.8% of its initial capacitance, demonstrating excellent cycling stability. This work indicated that the introduction of multifunctional organic acid offered a more efficient pore structure for facilitating charge transport and dextral charge storage for gel electrodes, as a result, significant enhancement in capacitive performances.
Study on factors affecting slip resistance performance of floor panels
Authors: Liu Yu , Kang Dugang , Lv Xiao , Chen Zhonggeng , Wan Shuai , Quan Yonglin , Tang Jia , Zhang Bo
Published: October 2024

In order to improve the slip resistence performance of floor panels used in escalators and moving walkways, as well as ensure the safety, the paper analyzes the impact of different factors on the slip resistence performance of floor panels through experiments. The test results reveal that the surface treatment degree of floor panels, environmental temperature and humidity, and passengers’ footwear all exert varying degress of impact on the slip resistence performance.
Investigation on heat transfer enhancement of PCM by tree-like fins
Authors: Guo Zishuo , Xu Li , Sun Feihu , Sun Si
Published: October 2024

The limited thermal conductivity of PCM significantly hampers the potential applications of phase change heat storage. To enhance heat transfer efficiency, fins can be incorporated into the phase change unit. In this study, two tree-like fins were designed based on fractal principles, and a transient model for fin-lauric acid phase change was established. Through numerical simulations, we investigated and compared the variations in liquid fraction of units equipped with fractal fins, traditional rectangular fins, and without any fins. In order to explore the variation of the heat transfer process in the units, the solid-liquid interface and temperature distribution were analyzed. The results demonstrate that due to their superior enhancement effect on heat conduction outweighing any inhibitory effects from natural convection, fractal fins exhibit significant improvements in heat transfer performance by shortening the complete melting time by 33.72% and 29.17%, respectively, for each type of tree-like fin.
Study on the effect of thickness on sound absorption performance of foam aluminum
Authors: Yuan Zhaodong , Zhu Kailin , Dang Sizheng , Zhu Yuanzhi
Published: October 2024

This paper investigates the effects of different thicknesses on the sound absorption performance of foam aluminum with different pore sizes through a combination of experiments and theoretical research. The results show that the average sound absorption coefficient of small-pore foam aluminum increases with increasing material thickness. As the thickness increases, there is a trend of the peak sound absorption performance shifting towards lower frequencies. In the mid-frequency range, although the sound absorption coefficient increases with the thickness of foam aluminum, the growth rate decreases. The average sound absorption coefficient of large-pore foam aluminum significantly increases with the material thickness and is reflected across various frequency ranges. With the increase in thickness, the sound absorption efficiency also improves, but the rate of improvement gradually slows down after reaching a certain thickness. Samples with the same thickness exhibit different performances in sound absorption coefficient, especially in frequencies above 2000Hz, where these differences are more pronounced. In the high-frequency range, the sound absorption coefficient of 100mm-thick large-pore foam aluminum material approaches 1, approximately 0.95.
Droplet bouncing electricity generation on graphene substrate
Authors: Li Dan , Chen Nan
Published: October 2024

Since the discovery of the phenomenon of droplets bouncing on hydrophobic surfaces, researchers have been dedicated to studying the underlying physical mechanisms of this phenomenon. Particularly, in recent years, researchers have focused on the observation that droplet bouncing can generate electrical signals. Inspired by this, we explore the potential applications of electrical signals generated by droplets (water droplets) bouncing in sensors and other relevant fields. In this study, we chose a well-established reduced graphene oxide (rGO) film, typical in the sensor field, as a substrate to investigate the bouncing electricity generation performance of water droplets on it. Three variable factors were considered, including droplet bouncing on rGO substrates with different inclinations, bouncing of droplets of different sizes at the same inclination on rGO substrates, and droplet dropping frequency, to investigate their effects on the electrical signals.
Optimal economic operation of smart home devices based on home microgrids and time-of-use tariffs
Authors: Liao Mengting , Yu Ling , Ding Baocang , Yu Min , Du Maochun
Published: October 2024

In this paper, a two-layer model is proposed for smart devices in a home energy management system in order to optimize residential energy use under time-of-use tariffs and home microgrids. Home smart devices are modelled based on their power consumption attributes and building thermal resistance. An HVAC-transferable device cooperative operation strategy is introduced to construct the economic optimization of the upper-level HVAC operation and the lower-level transferable device operation. This strategy reduces home power costs while maintaining user comfort. By iteratively solving the two-layer model, the optimal power consumption scheme for home smart devices is determined.
Soft robots and soft bodies: biological insights into the structure and function of fluidic soft robots
Authors: Zamanian Amir Hosein , Voltzow Janice
Published: October 2024

Over the last two decades, robotics engineering has witnessed rapid growth in the exploration and development of soft robots. Soft robots are made of deformable materials with mechanical properties or other features that resemble biological structures. These robots are often inspired by living organisms or mimic their locomotion, such as crawling and swimming. This paper aims to assist researchers in robotics and engineering to design soft robots incorporating or inspired by biological systems with a more informed perspective on biological models and functions. We address the characteristics of fluidic soft robots inspired by or mimicking biological examples, establish a method to categorize soft robots from a functional biological perspective, and provide a wider range of organisms to inspire the development of soft robotics. The actuation mechanisms in bioinspired and biomimetic soft robotics would benefit from a clearer understanding of the underlying principles, organization, and function of biological structures.
The dominant mechanisms of nutrient cycling in high-dam reservoirs: retention, transport or transformation?
Authors: Wu Yujiao , Li Yu , Du Erhu , Sun Yan , Zhang Jingjie , Liu Zhihong , Song Changchun
Published: October 2024

High-dam reservoirs can significantly affect nutrient cycling processes across the globe. However, the research community now has two contradictive views (i.e. retention versus transformation) about the impact of high-dam reservoirs on nutrient cycling due to incomplete information obtained from limited field samplings. To resolve this issue, we develop a physically-based, three-dimensional water quality model to examine the spatiotemporal distributions of biogenic elements (nitrogen and phosphorus) in high-dam reservoirs with high spatial and temporal details. We apply the model to the Xiaowan Reservoir, a representative high-dam reservoir in the Lancang River Basin. By scrutinizing the spatiotemporal distributions of biogenic elements across space and over time, we find a unique ‘retention-transformation-transportation’ process of nitrogen and phosphorus in the high-dam reservoir, with dominant transformation occurring in the water zone before the dam during non-flood period while dominant retention occurring in the middle part of a reservoir during flood period. We further find that transformations of biogenic elements are enhanced only in low-temperature and low-oxygen environments. Our findings show solid scientific basis to resolve the contradictive views about nutrient cycling mechanisms in high-dam reservoirs, and provide important policy implications for the operation of high-dam reservoirs to achieve improved water quality while maintaining clean energy supply.
Ornithological characterisation of the natural habitats’s Lake Dayet Er Roumi (Khemisset, Morocco)
Authors: Sadki M , Chahlaoui A , Belkhiri A , Maliki A , Saidi A , Khaffou M
Published: October 2024

The permanent natural lake located in the Dayet Er-Roumi lake ecosystem (N 33°74’ - W 6°19’) is a Site of Biological and Ecological Interest (SIBE) that is unique in a semi-continental region. This site has a distinct sub-humid microclimate, in marked contrast to the vast semi-arid zone that surrounds it. Located 15 kilometres south of the town of Khémisset, the lake is subject to significant human pressure due to its ease of access, its importance to local communities and its significant biological value.

The overall aim of this study is to analyse the Dayet Er-Roumi lake ecosystem, focusing on the site’s natural habitats and their interactions with the bird population. The study aims to provide an in-depth understanding of the environmental health and biodiversity of the lake, given the significant human pressure exerted on it. The research took place during the 2020-2021 campaign, with regular weekly analyses and observations.

Analysis of the ecology of bird populations and their natural environments at Lake Dayet Er-Roumi revealed a gradual deterioration in the natural habitats of the lake system. The latter includes wetland habitats such as surface water, the aquatic bed, emergents, trees and shrubs, woodlands and non-vegetative areas, as well as non-wetland habitats such as agricultural fields and residential areas. This alteration has a negative impact on the distribution of bird populations, whether sedentary or migratory. A total of 45 species were recorded during the study, but it is important to note that 4 of them have a dual status, with the following numbers: sedentary breeders (n=1), sedentary non-breeders (n=19), winterers (n=17), migratory passage birds (n=10), and occasional visitors (n=3).
Soil quality index: a tool to detect the sensitivity to soil erosion in an agricultural catchment from the Middle Atlas of Morocco.
Authors: Nadia Ennaji , Hasan Ouakhir , Said Halouan , Hassan Mosaid , Youness Abahrour , Mohamed Abahrour
Published: October 2024

The present paper focuses on the application of the Soil Quality Index (SQI) within the Tiguert catchment, situated in the Middle Atlas of Morocco. The studied catchment, covering approximately 10.2 km², experiences a semi-arid climate with irregular rainfall and is designated as an agricultural area, making it an ideal site for studying the intricate interactions between natural processes and human activities. The SQI developed as part of the Mediterranean Desertification and Land Use (MEDALUS) project is tailored to the unique conditions of the Mediterranean region. In the case of the Tiguert catchment, SQI is calculated using a formula that considers topographical slope, horizontal depth of soil, parental material, and soil brightness. Consequently, the results depict a promising scenario, with 61% of the soil classified as “High Quality,” indicating robust soil health and resilience despite the challenges posed by a semi-arid climate. The 31% categorized as “Moderate Quality” underscores areas requiring specific management attention, while the 8% identified as “Low Quality” signals localized challenges potentially influenced by irregular rainfall patterns. Furthermore, the SQI results are closely linked to soil erosion dynamics, with higher SQI values associated with improved resistance to erosion. The dynamic connection between precipitation patterns and SQI over a 40-year analysis indicates the impact of varying rainfall on soil health. Extreme rainfall events correspond to higher SQI percentages in the “High Quality” category, while drier periods align with lower SQI percentages, emphasizing the dynamic relationship between climate and soil quality. A comprehensive analysis of SQI across diverse ecosystems in Tiguert reveals variations in soil health, emphasizing the importance of tailored land management approaches for different land use types to optimize overall soil sustainability.
Modeling of ecological niches of Barbary Partridge (Alectoris barbara) under conditions of bioclimatic variability in the Fes-Meknes region (Morocco)
Authors: El fallah Kamal , El kharrim Khadija , Belghyti Driss
Published: October 2024

The Barbary Partridge (Alectoris barbara) is a bird species belonging to the Phasianidae family and is endemic to North Africa, including Morocco. Effective conservation of this species requires a thorough understanding and accurate assessment of the environmental factors that influence reproductive parameters. In this study, we used the species distribution models (SDM) to study the geographical distribution of the Barbary Partridge in Morocco. These models are tools that allow us to study the effects of climate change on the spatial distribution of species, they are based on the Maxent (maximum entropy) algorithm. These models are based on environmental and biological data and can predict the probability of a species’ occurrence in a given geographic area. They can also predict how climatic and environmental conditions will change over time and how these changes will affect the species’ distribution. The results obtained revealed that the environmental factors that have a significant influence on the distribution area of Barbary Partridge under Moroccan conditions are: annual precipitation (Bio12) with a contribution rate of 23.3%; precipitation of the driest quarter (Bio17) at 19.9%; altitude at 9.9%; minimum temperature of the coldest month (Bio 6) at 7.6%; precipitation of the driest month (Bio14) at 7.2%; and mean temperature of the wettest quarter (Bio8) at 4.4%. This information can be used to assist in long-term conservation planning by identifying areas that may become more or less suitable for the species.
The effect of climate change on the variation of low flow rates within mountainous basins: Case study of the Srou basin-Middle Atlas-Morocco (1976-2016)
Authors: Omar Ghadbane , Mohamed Chakir , Hasan Ouakhir
Published: October 2024

The study of hydro-climatic variability over extended periods is crucial for comprehending the effects of climate variability on water resources and the incidence of droughts. In Morocco, drought has historically afflicted the plains, eastern, and southern regions of the country. However, the impact of drought in mountainous areas has often been overlooked. Climate change has exacerbated this situation, as evidenced by significant water deficits experienced by Morocco in 1982 and 2007. These events underscore the vulnerability of regions to drought, especially during periods of low-flow. This study focuses on examining rainfall variability within the Srou River basin, and its impact on fluctuations in low-flow rates in the context of a changing climate. The analysis utilizes the Cumulative Sum method to assess these dynamics. Besides, rainfall data and monthly low-flow rates were analysed and assessed. The obtained results reveal a significant variability in rainfall across the watershed, with a general trend of decline punctuated by occasional brief wet periods. These drought episodes have led to diminished surface and groundwater resources within the area. This research sheds light on the pressing need to address hydro-climatic challenges and underscores the urgency of adaptation measures to safeguard water security in Morocco’s diverse geographical contexts.
Ecological Management of Stored Grain Pests: Global Insights and Future Directions
Authors: El Baghazaoui Rachid , Houssine Bouiamrine El , Nassiri Laila , Boutagayout Abdellatif , Belmalha Saadia
Published: October 2024

Post-harvest losses due to pests in cereals and pulse warehouses represent a major challenge to global food security. These losses have widespread negative impacts on the food supply chain, leading to the widespread use of synthetic insecticides to control the spread of pests in stored commodities. Although these chemicals are initially effective against warehouse pests, their prolonged use leads to increased resistance, resulting in increased health and environmental risks. In addition, the residues left by these synthetic insecticides can alter the quality of stored food, thereby posing a threat to human and animal health. In response to this problem, several studies have focused on ecological management aimed at combating warehouse pests without compromising the quality of stored grain. These studies include an assessment of traditional, ecological, and modern approaches as well as a summary of technological advances in cereal storage. This analysis describes new emerging ecological methods such as varietal resistance, use of semiochemicals, and physical and biological control methods. The challenges and research prospects associated with ecological practices were also discussed. It is emphasized that ecological control is not only safer and more sustainable in the long term but also contributes to the preservation of the environment and human health by reducing exposure to harmful substances.
Fabrication of hierarchically porous trabecular bone replicas via 3D printing with high internal phase emulsions (HIPEs)
Authors: Sengokmen-Ozsoz Nihan , Aleemardani Mina , Palanca Marco , Hann Alice , Reilly Gwendolen C , Dall’Ara Enrico , Claeyssens Frederik
Published: October 2024

Combining emulsion templating with additive manufacturing enables the production of inherently porous scaffolds with multiscale porosity. This approach incorporates interconnected porous materials, providing a structure that supports cell ingrowth. However, 3D printing hierarchical porous structures that combine semi-micropores and micropores remains a challenging task. Previous studies have demonstrated that using a carefully adjusted combination of light absorbers and photoinitiators in the resin can produce open surface porosity, sponge-like internal structures, and a printing resolution of about 150 µm. In this study, we explored how varying concentrations of tartrazine (0, 0.02, 0.04, and 0.08 wt%) as a light absorber affect the porous structure of acrylate-based polymerized medium internal phase emulsions fabricated via vat photopolymerization. Given the importance of a porous and interconnected structure for tissue engineering and regenerative medicine, we tested cell behavior on these 3D-printed disk samples using MG-63 cells, examining metabolic activity, adhesion, and morphology. The 0.08 wt% tartrazine-containing 3D-printed sample (008 T) demonstrated the best cell proliferation and adhesion. To show that this high internal phase emulsion (HIPE) resin can be used to create complex structures for biomedical applications, we 3D-printed trabecular bone structures based on microCT imaging. These structures were further evaluated for cell behavior and migration, followed by microCT analysis after 60 days of cell culture. This research demonstrates that HIPEs can be used as a resin to print trabecular bone mimics using additive manufacturing, which could be further developed for lab-on-a-chip models of healthy and diseased bone.
Standalone single- and bi-layered human skin 3D models supported by recombinant silk feature native spatial organization
Authors: Gkouma Savvini , Bhalla Nayanika , Frapard Solène , Jönsson Alexander , Gürbüz Hakan , Dogan Asli Aybike , Giacomello Stefania , Duvfa Martin , Ståhl Patrik L , Widhe Mona , Hedhammar My
Published: October 2024

Physiologically relevant human skin models that include key skin cell types can be used for in vitro drug testing, skin pathology studies, or clinical applications such as skin grafts. However, there is still no golden standard for such a model. We investigated the potential of a recombinant functionalized spider silk protein, FN-silk, for the construction of a dermal, an epidermal, and a bilayered skin equivalent (BSE). Specifically, two formats of FN-silk (i.e. 3D network and nanomembrane) were evaluated. The 3D network was used as an elastic ECM-like support for the dermis, and the thin, permeable nanomembrane was used as a basement membrane to support the epidermal epithelium. Immunofluorescence microscopy and spatially resolved transcriptomics analysis demonstrated the secretion of key ECM components and the formation of microvascular-like structures. Furthermore, the epidermal layer exhibited clear stratification and the formation of a cornified layer, resulting in a tight physiologic epithelial barrier. Our findings indicate that the presented FN-silk-based skin models can be proposed as physiologically relevant standalone epidermal or dermal models, as well as a combined BSE.
The impact of green credit on the green transformation of the manufacturing industry
Authors: Gao Dawei , Ma Meichen
Published: October 2024

Manufacturing’s green transformation is essential for advancing high-quality development. Green credit, which functions as a market-driven tool, offers support for achieving this transformation. Using manufacturing data from 30 provinces in China from 2005 to 2020, this research establishes a theoretical framework to analyze how green credit and marketization levels influence manufacturing’s green transformation. This research also provides an empirical analysis of how green credit influences this transition. The results are as follows: first, the growth of green credit plays a significant role in driving the green transformation of the manufacturing sector, with this finding remaining valid after a series of robustness and endogeneity tests. Second, the mechanism analysis shows that green credit supports the environmentally friendly transformation of the manufacturing industry through an improvement in R&D intensity. Third, moderation testing reveals that the process of marketization significantly strengthens the positive effect of green credit on the promotion of manufacturing’s green transformation Among them are the following, the relationship between the government and the market and the development of the product market inhibit the role of green credit in support of the green transformation of the manufacturing sector. The development of factor markets, the development of non-state-owned economies, and the development of market intermediary organizations and the legal system environment exert a facilitating function, which significantly enhances the positive effect of green credit in the promotion of the green transformation. The conclusions provide fresh insights and empirical evidence for advancing manufacturing’s green transformation and hold practical significance for refining green credit policies and advancing market-oriented reforms.
Optimization of microstructure and mechanical properties of 7075 aluminum alloy by equal channel angular pressing technology
Authors: Xu Gang , Li Shilin
Published: October 2024

The equal channel angular pressing technology, as an effective technique for modifying the surface of a material, has had a significant impact on the microstructure and mechanical properties of the 7075 aluminum alloy. The study achieved the refinement of 7075 aluminum alloy grains and the homogenization of the second phase particle distribution through equal channel angular pressing technology, thereby significantly improving the strength and plasticity of the material. Through orthogonal experimental design, the effects of extrusion angle, extrusion speed, and remelting temperature on material properties were studied. The results showed that appropriate ECAP parameters could effectively regulate the microstructure of 7075 aluminum alloy, thereby optimizing its mechanical properties. Especially in the analysis of equivalent strain rate, when the extrusion angle was 50°, the position of the maximum equivalent strain rate at the forefront point remained unchanged, but the equivalent strain rate decreased to 0.107−1. In the aging hardness analysis, when the number of equal channel angular pressing passes was 3, the aging hardness of G group 7075 aluminum alloy increased to 195HV in the first 5 min. The equal channel angular pressing technology can optimize the internal structure of 7075 aluminum alloy and improve the material’s plasticity and mechanical properties. The research provides important technical support for the application of 7075 aluminum alloy in high-end equipment manufacturing.