bluuebunny/crossref_metadata_2025 huggingface dataset:
A Highly Stretchable Force Sensitive and Temperature Sensitive Sensor Material with the Sandwich Structure of PDMS + PDMS/GaInSn + PDMS
Authors: Zhang Rongmin , Zhai Qianqian , Bao Fandou , Zhao Di , Lu Zhihua , Wang Jing , Wang Weina
Published: September 2023

Flexible conductive sensor materials have received great attention for their sensitive electrical response to external conditions and their promising applications in flexible wearable and robotic applications. In this work, a highly stretchable force sensitive and temperature sensitive sensor material with a sandwich structure was prepared from the polydimethylsiloxane (PDMS) and the liquid metal (LM) gallium–indium–tin alloy (GaInSn). The sandwich structure (PDMS + PDMS/GaInSn + PDMS) was proven to prevent the “leakage” of LM. The preparation method of the sensing material was simple and time-saving (less than 1.5 h) and can be used for industrial production. The electrical performance analysis results confirmed that the resistance (R) of the material was sensitive to the external force, such as repeated stretching, compressing, bending, and impacting. The ΔR/R changed periodically and stably with the repeated stretching, when the GaInSn/Part A ≥ 0.4, the cyclic tensile strain ≤ 50%, and the cyclic tensile rate ≤ 2.5 mm/min. The R of the sensor materials was also responsive to the temperature, such as hot air and liquid nitrogen. In conclusion, this work provides a method for preparing sensing materials with the sandwich structure, which was confirmed to be sensitive to force and temperature without leaking LM, and it produced different types of R signals under different deformations and different temperatures.
Enhanced Interfacial Properties of Carbon Fiber/Maleic Anhydride-Grafted Polypropylene Composites via Two-Step Surface Treatment: Electrochemical Oxidation and Silane Treatment
Authors: Kim Dong-Kyu , Han Woong , Kim Kwan-Woo , Kim Byung-Joo
Published: September 2023

The interfacial adhesion between carbon fibers (CFs) and a thermoplastic matrix is an important aspect that should be improved in manufacturing CF-reinforced thermoplastics with high strength and rigidity. In this study, the effects of a two-step surface treatment comprising electrochemical oxidation and silane treatment of the CF surface on the mechanical properties of CF/maleic anhydride-grafted polypropylene (MAPP) composites were confirmed. The surface characteristics of the treated CFs were analyzed via scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The tensile testing of a single CF and interfacial adhesion of the samples before and after the surface treatment were analyzed using a single-fiber testing machine and a universal testing machine. After the silane treatment, the roughness of the CF surface increased due to the formation of a siloxane network. In addition, the interfacial shear strength increased by ∼450% compared to that of the untreated CFs due to the covalent bond between the -NH2 end group of siloxane and MAPP. This two-step surface treatment, which can be performed continuously, is considered an effective method for improving the mechanical interface strength between the CF and polymer matrix.
Influence of the Print Envelope Temperature on the Morphology and Tensile Properties of Thermoplastic Polyolefins Fabricated by Material Extrusion and Material Jetting Additive Manufacturing
Authors: Hentschel Lukas , Petersmann Sandra , Kynast Frank , Schäfer Ute , Holzer Clemens , Gonzalez-Gutierrez Joamin
Published: September 2023

Additive manufacturing (AM) nowadays has become a supportive method of traditional manufacturing. In particular, the medical and healthcare industry can profit from these developments in terms of personalized design and batches ranging from one to five specimens overall. In terms of polymers, polyolefins are always an interesting topic due to their low prices, inert chemistry, and crystalline structure resulting in preferable mechanical properties. Their semi-crystalline nature has some advantages but are challenging for AM due to their shrinkage and warping, resulting in geometrical inaccuracies or even layer detaching during the process. To tackle these issues, process parameter optimization is vital, with one important parameter to be studied more in detail, the print envelope temperature. It is well known that higher print envelope temperatures lead to better layer adhesion overall, but this investigation focuses on the mechanical properties and resulting morphology of a semi-crystalline thermoplastic polyolefin. Further, two different AM technologies, namely material jetting (ARBURG plastic freeforming—APF) and filament-based material extrusion, were studied and compared in detail. It was shown that higher print envelope temperatures lead to more isotropic behavior based on an evenly distributed morphology but results in geometrical inaccuracies since the material is kept in a molten state during printing. This phenomenon especially could be seen in the stress and strain values at break at high elongations. Furthermore, a different crystal structure can be achieved by setting a specific temperature and printing time, also resulting in peak values of certain mechanical properties. In comparison, better results could be archived by the APF technology in terms of mechanical properties and homogeneous morphology. Nevertheless, real isotropic part behavior could not be managed which was shown by the specimen printed vertically. Hence, a sweet spot between geometrical and mechanical properties still has to be found.
Fracture Resistance of Fiber-Reinforced Composite Restorations: A Systematic Review and Meta-Analysis
Authors: Escobar Lorena Bogado , Pereira da Silva Lígia , Manarte-Monteiro Patrícia
Published: September 2023

Composite resin is universally used for posterior teeth restorations. Fibers have been suggested for the mechanical improvement of the restorations. This study assessed the fracture resistance of class II fiber-reinforced composite restorations and compared it with the fracture resistance of three control groups: (1) healthy teeth, (2) non-fiber-reinforced restorations and (3) unrestored cavities. A search was performed using PubMed, Web of Science and Google Scholar from 15 May to 12 June 2023. Only in vitro studies from the last 10 years were included for this systematic analysis. This study was registered in the PROSPERO database, it followed PRISMA guidelines and the risk of bias was assessed using the QUIN tool. Fracture resistance median values, in Newtons (N), were calculated for the experimental and control groups (95% confidence interval). For pairwise comparison, nonparametric tests (p < 0.05) were applied. Twenty-four in vitro studies met the inclusion criteria. The fracture resistance of the experimental group was 976.0 N and differed (p < 0.05) from all controls. The experimental group showed lower values of fracture resistance than healthy teeth (1459.9 N; p = 0.048) but higher values than non-fiber-reinforced restorations (771.0 N; p = 0.008) and unrestored cavities (386.6 N; p < 0.001). In vitro systematic outcomes evidenced that glass and/or polyethylene fibers improved the fracture resistance of composite restorations.
Effects of Electron Irradiation and Temperature on Mechanical Properties of Polyimide Film
Authors: Qiu Jian , Ma Jusha , Han Wenjia , Wang Xiao , Wang Xunchun , Heini Maliya , Li Bingyang , Sun Dongyang , Zhang Ruifeng , Shi Yan , Gao Cunfa
Published: September 2023

Polyimide (PI) is widely deployed in space missions due to its good radiation resistance and durability. The influences from radiation and harsh temperatures should be carefully evaluated during the long-term service life. In the current work, the coupled thermal and radiation effects on the mechanical properties of PI samples were quantitatively investigated via experiments. At first, various PI specimens were prepared, and electron irradiation tests were conducted with different fluences. Then, both uniaxial tensile tests at room temperature and the dynamic mechanical analysis at varied temperatures of PI specimens with and without electron irradiation were performed. After that, uniaxial tensile tests at low and high temperatures were performed. The fracture surface of the PI film was observed using a scanning electron microscope, and its surface topography was measured using atomic force microscopy. In the meantime, the Fourier-transform infrared spectrum tests were conducted to check for chemical changes. In conclusion, the tensile tests showed that electron irradiation has a negligible effect during the linear stretching period but significantly impacts the hardening stage and elongation at break. Moreover, electron irradiation slightly influences the thermal properties of PI according to the differential scanning calorimetry results. However, both high and low temperatures dramatically affect the elastic modulus and elongation at break of PI.
Interferometric Synthetic Aperture Radar Applicability Analysis for Potential Landslide Identification in Steep Mountainous Areas with C/L Band Data
Authors: Deng Jin , Dai Keren , Liang Rubing , Chen Lichuan , Wen Ningling , Zheng Guang , Xu Hong
Published: September 2023

Landslides frequently occur in the mountainous area of southwest China, resulting in infrastructure damage, as well as a loss of life and property. The use of interferometric synthetic aperture radar (InSAR) technology has become increasingly popular due to its wide coverage, high precision, and efficiency in identifying potential landslides in steep mountainous regions to mitigate risks. This study focused on the Mao County region in China and utilized a small baseline subset of InSAR (SBAS−InSAR) technology with Sentinel-1 and ALOS-2 data to identify the potential landslides and analyze their applicability. To ensure accuracy, the findings were verified using optical image and field surveys. Additionally, a comparative analysis was performed on C-band and L-band SAR data to examine differences in the coherence, geometric distortion, and displacement results, revealing that the L-band has clear advantages in the coherence, suitable observation coverage, and displacement results, while C-band can detect relatively slight displacements. This study aimed to determine the applicability of different SAR satellites for early landslide identification in steep mountainous areas, which can serve as a technical reference for selecting appropriate SAR data and enhancing InSAR identification abilities for potential landslides in the future.
Land–Atmosphere Interactions and Effects on the Climate of the Tibetan Plateau and Surrounding Regions II
Authors: Ma Yaoming , Zhong Lei , Jia Li , Menenti Massimo
Published: September 2023

As the world’s highest and largest plateau, the Tibetan Plateau (TP) is referred to as ‘the Asian Water Tower’ and ‘the Third Pole of the World’ [...]
Effects of Thermokarst Lake Drainage on Localized Vegetation Greening in the Yamal–Gydan Tundra Ecoregion
Authors: Liu Aobo , Chen Yating , Cheng Xiao
Published: September 2023

As the climate warms, the Arctic permafrost region has undergone widespread vegetation changes, exhibiting overall greening trends but with spatial heterogeneity. This study investigates an underexamined mechanism driving heterogeneous greening patterns, thermokarst lake drainage, which creates drained lake basins (DLBs) that represent localized greening hotspots. Focusing on the Yamal–Gydan region in Siberia, we detect 2712 lakes that have drained during the period of 2000–2020, using Landsat time-series imagery and an automated change detection algorithm. Vegetation changes in the DLBs and the entire study area were quantified through NDVI trend analysis. Additionally, a machine learning model was employed to correlate NDVI trajectories in the DLBs with environmental drivers. We find that DLBs provide ideal conditions for plant colonization, with greenness levels reaching or exceeding those of the surrounding vegetation within about five years. The greening trend in DLBs is 8.4 times the regional average, thus contributing disproportionately despite their small area share. Number of years since lake drainage, annual soil temperature, latitude, air temperature trends, and summer precipitation emerged as key factors influencing DLB greening. Our study highlights lake drainage and subsequent vegetation growth as an important fine-scale process augmenting regional greening signals. Quantifying these dynamics is critical for assessing climate impacts on regional vegetation change.
Estimating the Impacts of Ungauged Reservoirs Using Publicly Available Streamflow Simulations and Satellite Remote Sensing
Authors: Nguyen Ngoc Thi , Du Tien Le Thuy , Park Hyunkyu , Chang Chi-Hung , Choi Sunghwa , Chae Hyosok , Nelson E. James , Hossain Faisal , Kim Donghwan , Lee Hyongki
Published: September 2023

On the Korean Peninsula, the Imjin River is a transboundary river that flows from North Korea into South Korea. Therefore, human intervention activities in the upstream region can have a substantial impact on the downstream region of South Korea. In addition to climate impacts, there are increasing concerns regarding upstream man-made activities, particularly the operation of the Hwanggang dam located in the territory of North Korea. This study explored the feasibility of using the publicly available global hydrological model and satellite remote sensing imagery for monitoring reservoir dynamics and assessing their impacts on downstream hydrology. “Naturalized” streamflow simulation was obtained from the Group on Earth Observation (GEO) Global Water Sustainability (GEOGloWS) European Centre for Medium-Range Weather Forecasts (ECMWF) Streamflow Services (GESS) model. To correct the biases of the GESS-based streamflow simulations, we employed quantile mapping using the observed streamflow from a nearby location. This method significantly reduced volume and variability biases by up to 5 times on both daily and monthly scales. Nevertheless, its effectiveness in improving temporal correlation on a daily scale in small catchments remained constrained. For the reservoir storage changes in the Hwanggang dam, we combined multiple remote sensing imagery, particularly cloud-free optical images of Landsat-8, Sentinel-2, and snow-free Sentinel-1, with the area–elevation–volume (AEV) curves derived from the Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM). In assessing its hydrological impacts, the study found that overall impacts within the downstream catchment in Pilseung bridge of South Korea were generally less significant compared to the upstream Hwanggang catchment. However, there was a higher probability of experiencing water shortages during wet months due to the upstream dam’s operations. The study highlights the potential benefits of utilizing the publicly available hydrological model and satellite remote sensing imagery to supplement decision makers with important information for the effective management of the transboundary river basin in ungauged regions.
Evaluation of Susceptibility by Mass Movements through Stochastic and Statistical Methods for a Region of Bucaramanga, Colombia
Authors: Valencia Ortiz Joaquín Andrés , Martínez-Graña Antonio Miguel , Méndez Lenny Mejía
Published: September 2023

Mass movements are one of the hydrometeorological phenomena with the most negative impacts on the study area, and their evaluation through the calculation of susceptibility provides a tool of vital importance within territorial planning and disaster risk management on natural and anthropic environments. Their evaluation took algorithms designed within stochastic and statistical methods, such as the artificial neural network, the bivariate statistical method, and the logistic regression method, which integrate inherent variables (geoenvironmental characterization) against events or dependent variables. This correlation simulates regions with a probability of occurrence of mass movement under training or weight assignment. Its construction for this study took, as a basis, 50% of the events (test) and 50% of the events (validation) randomly and with equivalent area distribution against the inherent variables. As a result, it was observed that the bivariate method presented a good performance in spatial prediction. This model presents values of AUC = 82.2% (test) and AUC = 76.9% (validation), grouping a total of 591 events of the 856 events in the high category (69%). In turn, from a second evaluation carried out by this method to each hydrographic basin, a condition was established in the area (50 km2) for coherent results at a level of analysis 1:25,000, based on the idea that the variables do not present changes greater than 20% in their attributes, added to a knowledge of the area evaluated.
Irrigation Cooling Effect on Local Temperatures in the North China Plain Based on an Improved Detection Method
Authors: Hou Mengjie , Zhao Lin , Lin Aiwen
Published: September 2023

Irrigation has excellent potential for altering surface characteristics and the local climate. Although studies using site observations or remote sensing data have demonstrated an irrigation cooling effect (ICE) on the air temperature (Tem) and land surface temperature (LST), it is difficult to eliminate other stress factors due to different backgrounds. We characterized the irrigation effect as the differences (Δ) of LST and DCT (DCT = LST − Tem) between irrigated and adjacent non-irrigated areas. An improved method was proposed to detect it over the North China Plain (NCP) based on satellite observations. We also investigated the effects of irrigation on Tem, precipitation, NDVI, and ET, and explored the relationships between them. The results show that irrigation induced a decrease in the daytime/nighttime LST and DCT (−0.13/−0.09 and −0.14/−0.07 °C yr−1), Tem (−0.023 °C in spring), and precipitation (−1.461 mm yr−1), and an increase in NDVI (0.03 in spring) and ET (0.289 mm yr−1) across the NCP. The effect on nighttime LST and NDVI increased by 0.04 °C 10 yr−1 and 0.003 10 yr−1, and that on ET weakened by 0.23 mm 10 yr−1 during 2000–2015. The ICE on the LST had evident spatiotemporal heterogeneity, which was greater in the daytime, in the spring, and in the northern area of the NCP (dry–hot conditions). The daytime ICE in the NCP and northern NCP was 0.37 and 0.50 °C during spring, respectively, with the strongest ICE of 0.60 °C in Henan; however, the ICE was less evident (<0.1 °C) in the southern NCP throughout the year. The ΔNDVI, ΔET, and ΔTem were the main factors driving ICE, explaining approximatively 22%, 45%, and 25% of the daytime ICE, respectively. For every unit of these measures that was increased, the daytime ICE increased by about 7.3, 4.6, and 1.5 °C, respectively. This study highlights the broad irrigation effect on LST, ET, NDVI, and the climate, and provides important information for predicting climate change in the future. The improved method is more suitable for regions with uneven terrain and a varying climate.
An InSAR Deformation Phase Retrieval Method Combined with Reference Phase in Mining Areas
Authors: Wang Zhihong , Dai Huayang , Yan Yueguan , Ren Jintong , Zhang Yanjun , Liu Jibo
Published: September 2023

The acquisition of precise deformation data, including the entirety of the subsidence basin resulting from subterranean mining operations, assumes critical significance in the context of surface impairment monitoring during the course of mining activities. In light of the constraints associated with InSAR technology when applied to the surveillance of expansive deformation gradient mining regions, an innovative approach is advanced herein for InSAR deformation phase retrieval. This approach integrates a reference phase, derivable through a variety of means, including pre-existing models or measurements. Initially, the reference deformation phase is subjected to subtraction from the wrapped InSAR deformation phase, culminating in the derivation of the wrapped phase indicative of the residual phase. Notably, it is posited that the fringe density characterizing the wrapped phase of the residual phase is theoretically diminished in comparison to that of the InSAR wrapped phase. This reduction in complexity in phase unwrapping ensues as a direct consequence. Subsequent to this, the phase retrieval process is effectuated through the summation of the reference phase and the unwrapped phase pertaining to the residual phase. The study harnesses Sentinel-1A and ALOS PALSAR-2 data, employing the PIM-predicted outcomes and GNSS-RTK monitoring outcomes as reference phases for the execution of phase retrieval experiments in two designated study areas. The computation of subsidence is subsequently realized through the combination of the displacement vector depression angle model and the retrieved phase, with the accuracy thereof corroborated through the utilization of leveling data. The experimental findings underscore the efficacy of the reference phase retrieval methodology in securing a more precise deformation phase characterization within expansive deformation gradient mining regions, thereby demonstrating the suitability of this methodological approach.
SMFF-YOLO: A Scale-Adaptive YOLO Algorithm with Multi-Level Feature Fusion for Object Detection in UAV Scenes
Authors: Wang Yuming , Zou Hua , Yin Ming , Zhang Xining
Published: September 2023

Object detection in images captured by unmanned aerial vehicles (UAVs) holds great potential in various domains, including civilian applications, urban planning, and disaster response. However, it faces several challenges, such as multi-scale variations, dense scenes, complex backgrounds, and tiny-sized objects. In this paper, we present a novel scale-adaptive YOLO framework called SMFF-YOLO, which addresses these challenges through a multi-level feature fusion approach. To improve the detection accuracy of small objects, our framework incorporates the ELAN-SW object detection prediction head. This newly designed head effectively utilizes both global contextual information and local features, enhancing the detection accuracy of tiny objects. Additionally, the proposed bidirectional feature fusion pyramid (BFFP) module tackles the issue of scale variations in object sizes by aggregating multi-scale features. To handle complex backgrounds, we introduce the adaptive atrous spatial pyramid pooling (AASPP) module, which enables adaptive feature fusion and alleviates the negative impact of cluttered scenes. Moreover, we adopt the Wise-IoU(WIoU) bounding box regression loss to enhance the competitiveness of different quality anchor boxes, which offers the framework a more informed gradient allocation strategy. We validate the effectiveness of SMFF-YOLO using the VisDrone and UAVDT datasets. Experimental results demonstrate that our model achieves higher detection accuracy, with AP50 reaching 54.3% for VisDrone and 42.4% for UAVDT datasets. Visual comparative experiments with other YOLO-based methods further illustrate the robustness and adaptability of our approach.
Transformations in Local Social Action in Portugal
Authors: Gonçalves Hermínia , Ferreira Jorge
Published: September 2023

The decentralization of social functions to municipalities, also known as municipal decentralization, triggered new contexts of practice in municipal social intervention. Municipalities are now dealing with more work and a focus on working in partnerships, which calls for greater dynamism of the local social action teams. This process has pushed the social workers to practices that alternate between mediation through the construction of access to a universal standard of social rights and the development of social intervention models with specific access to certain contexts and social groups. The objective of this paper is to envision new forms of standardization of social action within the framework of municipal decentralization, combining place-based perspectives with community and structural social work. What can we learn from social workers’ perspectives on the context of social functions in order to envision forms of place-based standardization of municipal social action? We seek to analyze the professional visions of local social action systems reform, discussing new contexts of practice; new place-based functions; and their correlation with political mediation for universal and intermunicipal social rights, instrumental dimensions of concrete work, and dimensions of value attributed to practicing social work. We organized the research according to the phenomenological paradigm, mobilizing the qualitative method and the multiple-case study. Based on evidence from the discourse of all professionals involved in the study, the findings indicate that the transformations of local social action systems, associated with the processes of social functions decentralization, imply greater comprehensiveness of social intervention, the ability to work in partnerships, and new place-based approach matrices, but they also present challenges for social workers in terms of multilevel governance that may favor the standardization of access to better social well-being between municipal territories.
“Bad Students” and the Configuration of School Failure through Their Social Representations
Authors: Velasco Beltrán Ángela María , Velasco Beltrán Rocío del Pilar
Published: September 2023

Social representations can influence, to a great extent, the way in which we relate to people in different situations. In the educational environment, these representations—in terms of their adaptation or not to the school’s academic and behavioural demands—can lead to the school failure of those considered as “bad students”. Following an assessment, interviews and discussion groups were conducted with various members of an educational institution in the south of Bogotá to describe the social representations that prevail in this community about students who were at possible risk of school failure and how these representations could determine whether or not the student does indeed fail. Discourse analysis results yielded categories such as the differential construction between a “good student” and a “bad student” as well as stigmatization and conflicts with the school hierarchy and also showed how, occasionally, student failure is considered a consequence of family or social and economic factors unrelated to the school itself and to pedagogy. In conclusion, it is evident that there is an urgent need to establish institutional mechanisms that promote and adopt inclusion in educational relationships and practices from the perspective of the needs and interests of the most vulnerable pupils.
Investigating Disaster Mechanisms Triggered by Abrupt Overburden Fracture Alterations in Close-Seam Mining Beneath an Exceptionally Thick Sandstone Aquifer
Authors: Yan Tao , Zhu Chuanqu , Li Qingfeng , Xu Qian
Published: September 2023

The influx of roof water from exceptionally thick sandstone aquifers in northwestern China’s mining regions presents considerable challenges to the safety and productivity of coal mining operations. However, a significant gap in the literature persists concerning the underlying mechanisms. In this study, we investigated coal-seam mining beneath the exceptionally thick sandstone aquifer of the Zhiluo Formation at the Lingxin Coal Mine, utilizing this context as the basis for our engineering analysis. Our examination probed the hydrogeological and geomechanical mechanisms responsible for the abrupt alterations in overburden fractures and their catastrophic consequences during close-seam mining operations, employing research methodologies such as a theoretical analysis, fluid–structure-coupled simulation, and comparative evaluation. The study highlighted the intricate interplay between compressive-shear loads and the mechanics of hydraulic fracturing processes. The results revealed that in the absence of waterproof coal pillars, the downward mining of the L1614, L1615, and L1616 working faces led to the overlying rock’s water-conducting fractures reaching 204.9 m. This height was equivalent to 20 times the combined mining thickness of the three coal seams, impacting both the K3 and K4 aquifers. Conversely, when the water-resistant coal pillars were retained during the downward mining of the L1814, L1815, and L1816 working faces, the maximum height of the water-conducting fractures in the overlying rock was 103.5 m. This height was 10 times the combined mining thickness of the three coal seams, affecting only the K4 aquifer. Notably, vertical hydraulic fracturing was observed when the water pressure variation in the K3 aquifer exceeded 2–3 times its initial value. The water-conducting fracture zone was primarily characterized by the presence of “Type I-II” fractures, with the termination point of each fracture influenced by pressure and shear forces. Furthermore, we established a “fracture cracking and propagation model” and a “hydraulic fracturing-induced disaster model” based on the principles of fracture mechanics. We also provided formulas for calculating the cracking angles and extension heights of overburden fractures’ endpoints, which were derived from the maximum normal stress criterion.
One-Dimensional Compressibility and Creep Characteristics of Unsaturated Compacted Loess Based on Incremental Loading and Constant Rate of Strain Methods
Authors: Qin Pengju , Yan Qingchen , Lu Yu , Yang Chungang , Song Zhiwei , Li Chunbao
Published: September 2023

In engineering practice, unsaturated compacted loess is often utilized as a filling material in the loess regions. The loess inevitably undergoes one-dimensional compressibility and creep deformation due to the long-term effects of the upper soil layers and buildings. When the deformation is large enough, it tends to damage buildings and threaten engineering safety. In this regard, the one-dimensional compressibility and creep properties of unsaturated compacted loess based on incremental loading (IL) and constant rate of strain (CRS) methods have been studied. First, soil materials with an initial moisture content of 15% were prepared and then compacted into soil samples with an 80 mm diameter and a 10 mm height. Second, the compressibility and creep properties of the compacted loess samples obtained via the IL and CRS compression tests were compared and analyzed. In this study, several parameters, including the primary compression index Cc and secondary compression index Cα, were derived. Meanwhile, the moisture content of the samples was measured via electrical resistivity methods. Finally, the microstructural characteristics were derived via nuclear magnetic resonance (NMR) and scanning electron microscopy (SEM) tests. The results showed that Cc and Cα increased with the increase in moisture content and vertical stress; Cα/Cc ranged from 0.026 to 0.042. Compared with the compression parameters and deformation of the samples, those obtained via the CRS tests are a little larger than those obtained via the IL tests for a given loading and initial moisture content. The electrical resistivity depends on pore water-connected channels, which were deeply affected by the initial moisture content, vertical stress and loading duration (or strain rate). Moreover, as vertical stress increased, the pore size and pore area gradually decreased, the coarse particles were broken, and the fine particles increased. The contacts between particles changed from point-to-point contacts and edge-to-edge contacts to face-to-face contacts. Meanwhile, as vertical stress and loading rate increased, the loess particles were apt to vary from irregular elongated particles to equiaxial circular particles. This investigation can provide a theoretical base and experimental support for improving ground stability and preventing landslide disasters in loess regions.
Serum Trimethylamine N-Oxide Level Is Positively Associated with Aortic Stiffness Measured by Carotid–Femoral Pulse Wave Velocity in Patients Undergoing Maintenance Hemodialysis
Authors: Huang Po-Yu , Hsu Bang-Gee , Lai Yu-Hsien , Wang Chih-Hsien , Tsai Jen-Pi
Published: September 2023

Trimethylamine N-oxide (TMAO) is a biomarker that is effective in predicting major adverse cardiovascular (CV) events. Age-related vascular problems are significantly affected by aortic stiffness (AS), which is independently linked to CV morbidity and mortality. This study aimed to determine the association between serum TMAO levels and carotid–femoral pulse wave velocity (cfPWV) in patients receiving hemodialysis (HD) therapy. In total, 115 patients with HD were enrolled in this study. The AS group included patients whose cfPWV was >10 m/s. Using high-performance liquid chromatography and mass spectrometry, the levels of serum TMAO were measured. The AS group included 42 (36.5%) patients, and compared with the non-AS group, the rates of diabetes, hypertension, older age, systolic blood pressure, serum glucose, and TMAO levels were high. In the multivariate logistic regression analysis, serum TMAO and age were independently linked with AS after correcting for the factors significantly associated with AS. Following multivariate stepwise linear regression analysis, serum TMAO in these individuals was found to be strongly correlated with cfPWV values (p < 0.001). In patients on chronic HD, serum TMAO level is an independent measure of AS and strongly correlated with cfPWV.
Long-Term Exposure to Microcystin-LR Induces Gastric Toxicity by Activating the Mitogen-Activated Protein Kinase Signaling Pathway
Authors: Liu Ying , Li Yafang , Tan Qinmei , Lv Yilin , Tang Yan , Yang Yue , Yao Xueqiong , Yang Fei
Published: September 2023

Previous studies have primarily concentrated on the hepatotoxicity of MC-LR, whereas its gastric toxicity effects and mechanisms of long-term exposure under low dosage remain unknown. Herein, the gastric tissue from C57BL/6 mice fed with drinking water contaminated by low-dose MC-LR (including 1, 60, and 120 μg/L) was investigated. The results obtained showed that exposure to different concentrations of MC-LR resulted in significant shedding and necrosis of gastric epithelial cells in mice, and a down-regulation of tight junction markers, including ZO-1, Claudin1, and Occludin in the stomach, which might lead to increased permeability of the gastric mucosa. Moreover, the protein expression levels of p-RAF/RAF, p-ERK1/2/ERK1/2, Pink1, Parkin, and LC3-II/LC-3-I were increased in the gastric tissue of mice exposed to 120 μg/L of MC-LR, while the protein expression level of P62 was significantly decreased. Furthermore, we found that pro-inflammatory factors, including IL-6 and TNF-ɑ, were dramatically increased, while the anti-inflammatory factor IL-10 was significantly decreased in the gastric tissue of MC-LR-exposed mice. The activation of the MAPK signaling pathway and mitophagy might contribute to the development of gastric damage by promoting inflammation. We first reported that long-term exposure to MC-LR induced gastric toxicity by activating the MAPK signaling pathway, providing a new insight into the gastric toxic mechanisms caused by MC-LR.
Lysimeter Sampling System for Optimal Determination of Trace Elements in Soil Solutions
Authors: Fernando Salani U. , Galagedara Lakshman , Krishnapillai Mano , Cuss Chad W.
Published: September 2023

Understanding trace element (TE) composition and behavior in soil solution is extremely important for assessing ecological and human health impacts. Using lysimeters to collect soil solution with minimum alteration to the in situ phase distribution and concentration of TEs will facilitate a more accurate assessment. However, different lysimeter materials and sampling conditions may lead to vastly different results, demonstrating the need for the optimal choice of lysimeter depending upon environmental conditions. There is no general agreement or overview discussing the best lysimeter type and sampling system to use under various conditions. This review provides a critical summary of various lysimeters that can be used to collect soil solutions for the analysis of TEs and thereby provides key guidance for developing the best lysimeter sampling system for conditions and research questions of interest. This includes a range of aspects related to lysimeters, such as different types and materials, the basic principles of design and operation, advantages and disadvantages, challenges and limitations, techniques for cleaning and pretreatment, correct installation procedures, the influence of soil physical and chemical properties on sampling, and existing research gaps within this field.
Evaluating Climate Change Effects on a Snow-Dominant Watershed: A Multi-Model Hydrological Investigation
Authors: Sharifinejad Ali , Hassanzadeh Elmira
Published: September 2023

Assessing the impact of climate change on water systems often requires employing a hydrological model to estimate streamflow. However, the choice of hydrological model, process representation, input data resolution, and catchment discretization can potentially influence such analyses. This study aims to evaluate the sensitivity of climate change impact assessments to various hydrological modeling configurations in a snow-dominated headwater system in Alberta, Canada. The HBV-MTL and GR4J models, coupled with the Degree-Day and CemaNeige snowmelt modules, were utilized and calibrated using point- and grid-based climate data on lumped and semi-distributed catchment discretization. The hydrological models, in conjunction with a water allocation model, were supplied with climate model outputs to project changes in the basin. While all models revealed a unanimous increase in peak flow, the difference between their estimations could be as substantial as 42%. In contrast, their divergence was minimal in projecting median flow. Furthermore, most models projected an aggravated water supply deficit between 16% and 40%. Overall, the quantified climate change impacts were the most sensitive to the choice of snow routine module, followed by the model type, catchment discretization, and data resolution in this snow-dominant basin. Therefore, particular attention should be given to the proper representation of snowmelt processes.
Multivariate Drought Risk Analysis for the Weihe River: Comparison between Parametric and Nonparametric Copula Methods
Authors: Liu Fengping , Wang Xu , Chang Yuhu , Xu Ye , Zheng Yinan , Sun Ning , Li Wei
Published: September 2023

This study analyzed the multivariate drought risks for the Wei River basin by characterizing the interdependence between the standardized precipitation index (SPI) and the standardized precipitation evapotranspiration index (SPEI). Both parametric and nonparametric copulas were adopted to quantify the dependence between the SPI and SPEI. The results indicated that the Gaussian copula demonstrated the best fit in most cases, while the nonparametric copula method showed superiority over the parametric models at only one out of eighteen meteorological stations. The joint return periods (TOR, TAND, and TKendall) were computed through copula modeling, providing valuable insights into the co-occurrence of extreme drought events. For the SPI and SPEI with a 50-year return period, the TOR values range from 25.5 to 37.9 years, the TAND values fluctuate between 73.4 and 1233 years, and the TKendall values range from 60.61 to 574.71 years, indicating a high correlation between the SPI and SPEI in the study area. The spatial analysis revealed varying patterns across the basin with some regions more prone to experiencing simultaneous drought conditions characterized by both the SPI and SPEI. Furthermore, our results indicated that the SPEI exhibited more severity in drought characterization than the SPI due to its consideration of temperature effects. The disparities in the spatial features of the SPI and SPEI underscore the importance of incorporating multiple meteorological factors for a comprehensive drought risk analysis. This research contributes to a better understanding of the drought patterns and their joint risks in the Wei River basin, offering valuable information for drought preparedness and water resource management.
Characteristics of Dissolution Changes in Carbonate Rocks and Their Influencing Factors in the Maocun Basin, Guilin, China
Authors: Mo Chunmeng , Xin Shenglin , Huang Fen , Cao Jianhua , Xiao Junbo
Published: September 2023

Karstification and the global carbon cycle are closely related. Understanding the features of dissolution variations in carbonate rocks and the variables influencing carbonate dissolution is crucial for producing reliable estimates of karst carbon sinks. The seasonal variations in carbonate dissolution rates and the primary factors affecting carbonate dissolution in the Maocun watershed, Guilin, are examined under external source water (Xiaolongbei), karst water (Beidiping), and the mixed external source water and karst water (Bianyan) conditions. In this work, the characteristics of carbonate dissolution rates in several water bodies are investigated using field sampling and indoor experimental measurements. A correlation analysis is performed to analyze the key environmental factors impacting carbonate dissolution. The findings demonstrate that there is a clear seasonal and regional variation in the rate of the dissolution of carbonate rocks. The seasonal characteristics of the carbonate dissolution rate are summer > autumn > spring > winter. The carbonate dissolution rate ranges from −0.023 to 0.258 mg/cm2/d, with a mean value of 0.068 mg/cm2/d. The variation in carbonate dissolution rates on a spatial scale is characterized by exogenous water (Xiaolongbei) > exogenous water mixed with karst water (Bianyan) > karst water (Beidiping). As the rate of carbonate erosion in the Maocun basin is influenced by many factors, the correlation analysis shows that the main controlling factors for the rate of carbonate erosion in the Maocun basin are flow, the saturation index, pH, and pCO2. Seasonal variations in carbonate dissolution rates are mainly influenced by pCO2 and the flow rate, and the spatial variations are mainly influenced by pH and the saturation index. The results of this study are important for the scientific assessment of karst development in the study area and the accurate estimation of karst carbon sinks.
Numerical Investigation for Rehabilitation and Lining of a Problematic Canal
Authors: Ibrahim Amir , Khater Abdel Hamed M. , Gad Christina F. , Elzahry Elzahry Farouk M.
Published: September 2023

Canal lining and rehabilitation aim to distribute water, reduce losses, and ensure that water reaches the ends of the canals. Recognizing the need to improve the management of the irrigation system and maintain the width of strategic adjacent roads to canals, the Western Meleg Canal in Menoufia Governorate, Egypt, was selected as a case study. A reach of 1500–3400 km faces problems that impede the implementation of the lining sector as a result of the proximity of the buildings that could not be removed on the canal banks. Two alternatives, including the contraction of the bed width or coverage of the reach from 1500 km to 3400 km on the Western Meleg Canal, were explored. A coupled one-two dimensional numerical model to replicate the water surface profile and flow velocity was implemented. The total cost of each alternative was approximately estimated. The results show that the contraction of the bed width along the considered reach has a limited effect on the levels and velocities of water along the canal, as water levels increased by 2 to 6 cm from the design levels before the contraction of the width of the bed, and the maximum velocity of the water was 0.72 m/s. In the case of covering the selected reach, the difference in water pressure through the coverage (1500:4000 km) was 74 cm, and the coverage works under free flow. The estimated cost of covering is more than four times the cost of plain concrete lining. The findings of this study may help decision-makers and could be implemented in other such canals.
Cultura financiera y su incidencia en la economía familiar de los habitantes del cantón Macará, Ecuador.
Authors: Ochoa Herrera Johanna Maribel , Tandazo Luis Gustavo
Published: September 2023

Los cambios graduales en la economía son el producto de un mundo cada vez más globalizado. La cultura financiera es la medida de los conocimientos adquiridos por educación y herencias de comportamientos generacionales, estos pueden incidir en las finanzas personales y el bienestar económico de las familias. Para obtener un buen nivel de cultura financiera debe existir dominio en los términos financieros y control en los comportamientos de ahorro y deuda, esto con la finalidad de tomar decisiones asertivas con respecto a la gestión del dinero. El artículo tiene como objetivo medir la cultura financiera del cantón Macará y relacionarla con la economía familiar, para ello, se utilizaron varios estudios relacionados al tema en mención y se identificó algunos métodos que miden la situación financiera de varios países en Latinoamérica. El método aplicado para la investigación es un análisis de Chi-cuadrado, apoyado del coeficiente V de Cramer, para así demostrar la asociatividad de las variables. La información se recolectó a través de una encuesta a 377 familias, posteriormente, se dio el respectivo tratamiento de la data para estimar los resultados. Los principales hallazgos demuestran que las relaciones entre cultura financiera frente al ahorro, nivel de endeudamiento y el presupuesto de gastos familiares no tienen correspondencia significativa. Por tal motivo, se deduce que la economía de los hogares en las familias macareñas no dependen del conocimiento financiero
Operational Cyber Risk in the differing business model of Insurance Companies: the example of Poland
Authors: Hęćka-Sadowska Aleksandra , Łyskawa Krzysztof
Published: September 2023

Cybersecurity has become one of the greatest challenges in today’s post pandemic, digital and interconnected world, and also a subject of strategic importance for the insurance industry. There is no doubt that the advance of technology and the increased use of big data and cloud computing have set up an opportunity for insurance business, but they also expanded insurance companies’ vulnerabilities towards cyber risk. As insurers collect a large amount of confidential data, including protected personal sensitive information, they are a natural target for cyber-attacks. On the one hand, the aim of the article is to indicate how the risks associated with digitalisation affect the day-to-day operations in selected business areas of an insurance company, and which methods may be used to manage them, on the other. After a general review of cyber risk based on recent branch reports and survey results, the authors identified its global economic impact with particular regard to financial institutions, and also insurers’ exposure and perception of cyber risk and cybersecurity spending. Moreover, administrative decisions issued by the President of the Personal Data Protection Office in Poland, selected jurisdictions and loss scenarios for insurance companies were examined with a deeper dive into underwriting, selling, administration and claims handling processes. The results of the literature study show that cyber risk is recognized to be one of the most significant non-financial risks (in terms of the source, not result of the risk) for insurers and that many proactive security measures can be implemented. However, due to the high vulnerability to leaks of confidential personal and financial data or unauthorized system access, which may cause not only financial loss, but also business interruptions and reputational damage, in the authors’ opinion, loss prevention and reduction are insufficient. Thus, both insurance and non-insurance methods of external financing cyber risk results were indicated. On this basis, the cyber insurance is considered by the authors to be the best tool providing both prevention and financial compensation in case of cyber incidents, also in insurance companies.