bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic characteristics and energy evolution of granite subjected to coupled static–cyclic impact loading
Authors: Wang Xinyu , Liu Zhongyang , Gao Xicai , Li Pengfei , Dong Bin 
Published: May 2023

Abstract
In many underground rock projects, rock masses are subjected to coupled static–cyclic dynamic loading. In this paper, dynamic tests were carried out on granite specimens using a modified split Hopkinson pressure bar to study the dynamic characteristics and energy evolution of the rock under coupled static–cyclic impact loading. The results show that both the dynamic characteristics and the energy evolution of granite are sensitive to the number of repeated impacts and the confining pressure. Under the same confining pressure, the dynamic increase factor (DIF), dynamic elastic modulus, and transmitted energy ratio decreases, while the cumulative dissipated energy, cumulative specific energy dissipation and dissipated energy density tend to increase as more impact cycles are applied. The effect of confining pressure on enhancing the mechanical property of the rock is pronounced: the peak stress of rocks under confining pressure during cyclic impact is higher than their quasi-static compressive strength, and the DIF increase as the confining pressure increases. However, its effect on the dynamic elastic modulus is fairly insignificant. The confining pressure could change the crack propagation path of the specimens, and the failure mode is mainly a tensile failure, with no obvious axial splitting. By increasing the confining pressure, the energy dissipation capacity of the rock is significantly improved, and its increased rate of internal damage could be slowed down.

Graphical abstract
Meteorological Pre-warning Grade of High Temperature During Flowering Stage for Summer Maize in North China Plain
Authors: Li Shuyan , Fang Wensong , Liu Tianxue , Ma Zhihong , Noor Mehmood Ali , Liang Lu , Ma Wei , Xue Changying 
Published: May 2023

AbstractHigh temperatures during flowering stage affects the seed setting in maize and thereby result in significant yield penalties in recent changing climate era. Based on the daily maximum temperature data of the maize growing season from 1971 to 2019 at the surface meteorological observatory in Henan Province of China and maize observation data at the agricultural meteorological observatory, an early warning grade of high temperatures during the summer maize flowering stage was constructed. The daily maximum temperature of the summer maize flowering stage was ≥ 32 °C as the critical threshold of high temperature disaster, and ≥ 35 °C as the threshold of high temperature disaster. The number of high temperature days (HD) ≥ 32 °C and ≥ 35 °C during 10 days of the summer maize flowering stage were counted. The sequence of high temperature days of summer maize flowering stage was constructed and its normal distribution characteristics were verified. The quartile value of the normal distribution sequence was selected as the threshold value of high temperature in different grades, and the high temperature heat damage in the summer maize flowering stage was divided into three early warning meteorological grades. The index verification of the early warning meteorological grade was carried out by using the observation data of kernel number per ear in the agricultural meteorological station for maize. The results showed that the three grade indexes corresponding to the number of high temperature days with daily maximum temperature ≥ 32 °C were: 3 ≤ HD < 5 (Grade I), 5 ≤ HD < 7 (Grade II), and HD ≥ 7 (Grade III) and the three grade indexes corresponding to high temperature days ≥ 35 °C were: 2 ≤ HD < 3 (Grade I), 3 ≤ HD < 5 (Grade II), HD ≥ 5 (Grade III). The constructed indexes were verified as follows, the number of high temperature days ≥ 32 °C at about 90% stations was significantly negatively correlated with the number of maize grains per ear, and 74% stations which the number of high temperature days ≥ 35 °C was significantly negatively correlated with the number of maize grains per ear. Applying this index to evaluate the high temperature risk in the flowering period, we can indicate that the high temperature risk had trend of increasing gradually from north to south. In conclusion, the constructed high temperature warning meteorological grade index during the flowering stage could accurately reflect the damage grade of maize during the flowering stage.
Effects of Mineral and Organic Fertilization on Forage Maize Yield, Soil Carbon Balance, and NPK Budgets, Under Rainfed Conditions in the Azores Islands (Portugal)
Authors: Pacheco Carlos Arruda , Oliveira André , Tomaz Alexandra 
Published: May 2023

AbstractGreen organic fertilizers can be a valuable option to reduce the use of chemical fertilizers, improve the physical and chemical properties of soil, and promote circular agriculture. The effects of two fertilization schemes, (i) a combination of mineral fertilizers with dairy farm slurry (TA) and (ii) an organic substrate (SO) from green waste (TB), on soil fertility and forage maize (Zea mays L.) yield were studied in an on-farm trial in the Azores Island of S. Miguel (Portugal). For this purpose, soil chemical parameters were evaluated on three sampling dates, forage maize yield and yield components were compared, and the balances of soil carbon (SC), nitrogen (N), phosphorus (P), and potassium (K) were evaluated. The results showed that the maize yield obtained in TB was significantly higher than in TA. The differences in precipitation that occurred over the two years influenced the yield in both treatments. The SC, available P, and pH were significantly higher in TB at every sampling date, mainly in the subsurface layer, and overall enrichment in nitrogen was observed. Despite the need to extend this evaluation over a longer period, the results indicate that the application of SO could be an alternative to conventional mineral fertilization in forage maize in the Azores and in similar cropping systems in regions of temperate insular nature.
3D printable electroconductive gelatin-hyaluronic acid materials containing polypyrrole nanoparticles for electroactive tissue engineering
Authors: Serafin Aleksandra , Culebras Mario , Oliveira J. Miguel , Koffler Jacob , Collins Maurice N. 
Published: May 2023

AbstractElectrically conductive bio-scaffolds are explored in the field of tissue engineering (TE) as a solution to address the clinical need of electroactive tissues, finding applications in nervous, cardiac, and spinal cord injury repair. In this work, we synthesise polypyrrole nanoparticles (PPy NP) via the mini-emulsion method with further combination with a gelatin/hyaluronic acid (HA) hydrogel to create electroconductive Gel:HA:PPy-NP TE scaffolds. Electroconductive Gel:HA:PPy-NP scaffolds possess excellent mechanical properties at 1.08 ± 0.26 MPa, closely matching the reported mechanical performance of the spinal cord. Scaffolds were designed with controlled porosity of 526.2 ± 74.6–403.9 ± 57.4 µm, and conductivities of 4.3 × 10–6 ± 1.1 × 10–6 S.cm−1 were reached. Rheological studies show that prior to lyophilisation, the Gel:HA:PPy-NP hydrogels display a shear-thinning behaviour. These gels were subsequently 3D printed into predefined 2 layer lattice geometries and displayed excellent post-printing shape fidelity. In vitro studies show that the Gel:HA:PPy-NP scaffolds are cytocompatible with mesenchymal stem cells and neuronal stem cells and display encouraging cell attachment and proliferation profiles. Based on these results, the incorporation of PPy NPs into Gel:HA biomaterial scaffolds enhances the conductive capabilities of the material, while showcasing biocompatible behaviour with cell cultures. Hence, Gel:HA:PPy-NP scaffolds are a promising TE option for stimulating regeneration following nervous tissue injury.
Hysteresis performance of section steel reinforced concrete-filled rectangular stainless steel tubular columns
Authors: Xie Enpu , Wang Yang , Bao Yibei , Huang Kun , Zhang Xianjiang 
Published: May 2023

AbstractDue to high bearing capacity and excellent seismic performance, the section steel reinforced concrete-filled rectangular steel tube has been widely applied in engineering. The application of stainless steel for outer steel tube can improve the durability performance of members. In this study, ABAQUS software was used to perform nonlinear seismic analysis on section steel reinforced concrete-filled rectangular stainless steel tubular columns, and the numerical model was validated against experimental data. The mechanism and parametric study of the hysteresis performance were conducted. These parameters mainly include: concrete strength, strength of stainless steel, strength of section steel, steel ratio of stainless steel tube, steel ratio of section steel, axial compression ratio, and slenderness ratio. The analysis results showed that: increasing the strength of stainless steel tube and concrete can significantly improve the bearing capacity of members, but the strength of section steel has little effect; the bearing capacity decreases with the increasing slenderness ratio; when the axial compression ratio is smaller than 0.4, increasing axial compression can improve the bearing capacity. The strength of each material shows little influence on the shape of load–displacement skeleton; the axial compression ratio presents high effect on the shape of descending stage of curve, and the larger the axial compression ratio, the steeper the descending stage; the slenderness shows high influence on curve shape, and the larger the slenderness, the less the elastic stiffness, and the more gentle the descending stage of curve. Finally, a simplified load–displacement hysteretic model was proposed, which exhibits good agreement with finite element numerical analysis.
Boosting Adversarial Training Using Robust Selective Data Augmentation
Authors: Rasheed Bader , Masood Khattak Asad , Khan Adil , Protasov Stanislav , Ahmad Muhammad 
Published: May 2023

AbstractArtificial neural networks are currently applied in a wide variety of fields, and they are near to achieving performance similar to humans in many tasks. Nevertheless, they are vulnerable to adversarial attacks in the form of a small intentionally designed perturbation, which could lead to misclassifications, making these models unusable, especially in applications where security is critical. The best defense against these attacks, so far, is adversarial training (AT), which improves the model’s robustness by augmenting the training data with adversarial examples. In this work, we show that the performance of AT can be further improved by employing the neighborhood of each adversarial example in the latent space to make additional targeted augmentations to the training data. More specifically, we propose a robust selective data augmentation (RSDA) approach to enhance the performance of AT. RSDA complements AT by inspecting the quality of the data from a robustness perspective and performing data transformation operations on specific neighboring samples of each adversarial sample in the latent space. We evaluate RSDA on MNIST and CIFAR-10 datasets with multiple adversarial attacks. Our experiments show that RSDA gives significantly better results than just AT on both adversarial and clean samples.
A Survey of Ski Patrols in the United States Comparing Medical Direction, Patroller Training, and Patient Care
Authors: Fell Lindsey L. , Linney Olivia S. , DeLoughery Thomas G. , Johnston Emily E. 
Published: May 2023

Introduction Ski patrols are tasked with substantial challenges: distance from definitive care, complex extrications, and winter environments. Rules for US ski patrols stipulate that ≥1 persons be trained in basic first aid, but no further regulations regarding the specifics of provided medical care exist. This project investigated patroller training, patient care, and medical direction of US ski patrols through a survey of ski patrol directors and medical directors. Methods Participants were contacted via email, phone, and personal contacts. After consultation with known ski patrol directors and medical directors for question guidance, 2 separate institutional review board-approved surveys were designed: 1 for ski patrol directors and 1 for ski patrol medical directors, containing 28 and 15 qualitative questions, respectively. The surveys were distributed with a link to the encrypted Qualtrics survey platform. After 2 reminders and 4 mo, results were downloaded from Qualtrics into an Excel spreadsheet. Results Twenty-two responses from patrol directors and 15 from medical directors were received. The response rate is unknown. Outdoor emergency care certification was the minimum medical training required by 77% of the study participants. Twenty-seven percent of surveyed patrols belonged to an emergency medical service agency. Fifty percent of 11 surveyed ski patrols had a medical director, 6 of whom were board certified in emergency medicine. All surveyed medical directors stated that they assisted with patroller education, and 93% assisted with protocol development. Conclusions The surveys demonstrated variability in patroller training, protocols, and medical directorship. The authors questioned whether ski patrols would benefit from increased standardization of care and training, quality improvement programs, and medical directorship.
Fine Structure of Tremor Migrations Beneath the Kii Peninsula, Southwest Japan, Extracted With a Space‐Time Hough Transform
Authors: Sagae Kodai , Nakahara Hisashi , Nishimura Takeshi , Imanishi Kazutoshi 
Published: May 2023

AbstractTectonic tremors occurring on subducting plate boundaries are known to migrate at various timescales and migration speeds. Spatiotemporal patterns of tremor migration are key to investigating the rupture growth of slow earthquakes. However, spatiotemporal patterns are not sufficiently simple to visually define tremor migrations. This study developed a space‐time Hough transform to objectively extract tremor migrations. The space‐time Hough transform enables the extraction of multiple tremor migrations with various durations, migration directions, and migration speeds. We applied this method to a catalog of tremors for the period from 2012 to 2014, which was determined from the data analysis of a dense seismic array deployed in the Kii Peninsula, Southwest Japan. We successfully extracted 1,010 tremor migrations with durations ranging from 10 min to 24 hr. Along‐strike migrations propagating southwestward were predominant in the northeastern part of the Kii Peninsula, whereas those propagating northeastward were principal in the southwestern part. Regarding the along‐dip direction, tremor migrations propagating in the up‐dip directions were predominant in the deep part, and those propagating in the down‐dip directions were principal in the shallow part. The patterns of along‐strike migrations were related to the distribution of tremor energies, suggesting that tremor migrations may be controlled by heterogeneous structures of frictional properties on the plate interface. We further found that the migration speed is proportional to the inverse of the square root of the duration. This relation implies that a diffusion process controls the growth of fault ruptures behind tremor migrations.
Inter‐Annual Variability in Phytoplankton and Nutrients in the Gulf of Elat/Aqaba
Authors: Berman Hadar , Gildor Hezi , Fredj Erick 
Published: May 2023

AbstractThe Gulf of Elat/Aqaba exhibits high inter‐annual variability in mixed layer depth. Observations from the northern Gulf show differences of hundreds of meters in winter mixing depth, which ranges between 300 m in years with shallow mixing and up to 700 m in years with deep mixing. Deep mixing events can occur in two consecutive years or after four consecutive years of shallow mixing. The mixing depth has an effect on the concentration of nutrients and chlorophyll (and other tracers) in the surface and deep water. Using a 3D coupled physical‐ecological model, we studied the effect of shallow versus deep mixing on the processes controlling the phytoplankton bloom and on nutrient accumulation in the deep water. We found that years with deep mixing are characterized by larger spatial variability in surface and integrated chlorophyll concentration during the mixing season. We found that horizontal advection is a dominant contributor for integrated phytoplankton concentration in years with deep mixing in the northern Gulf. Even when mixing was deep and nutrient limitation decreased, light limitation on phytoplankton integrated growth was enhanced in the north compared with the south. In addition, we showed that the nutrient accumulation in the deep water after a year with deep mixing in the northern Gulf was initially affected mostly by physical processes (such as advection and vertical mixing), and less from ecological regeneration, and switched to be dominated by ecological processes alone during the third year after mixing.
Friction Experiments on Lunar Analog Gouges and Implications for the Mechanism of the Apollo 17 Long Runout Landslide
Authors: Magnarini G. , Aretusini S. , Mitchell T. M. , Pennacchioni G. , Di Toro G. , Schmitt H. H. 
Published: May 2023

AbstractThe Light Mantle landslide is a hypermobile landslide on the Moon. Apollo 17 astronauts collected a core sample of the top 60 cm of the Light Mantle deposit, which is currently being analyzed as part of the NASA's Apollo Next Generation Sample Analysis program. The origin of its hypermobility remains undetermined, as the proposed mechanisms are difficult to prove because of the lack of theoretical and experimental support and the scarcity of field data related to the internal structures of its deposit. Regardless of the emplacement mechanisms, it has been proposed that localized dynamic frictional weakening is responsible for the early stage instability that leads to catastrophic failure. Here, we conduct friction experiments under vacuum to investigate the viability of dynamic friction weakening in lunar analog anorthosite‐bearing gouges (i.e., rock powders). Our results show that localized dynamic friction weakening does not occur in these gouges at loading conditions where, instead, weakening is observed in other materials on Earth. Therefore, possibly other fluidization‐related mechanisms contributed to the initiation of the hypermobile Light Mantle landslide. Finally, we describe the microstructures formed in the experiments, including the presence of clast cortex aggregates. Preliminary investigation of the Light Mantle core samples (73001/73002) shows the presence of similar microstructures. Therefore, our microstructural observations will help the analysis and interpretation of the Apollo 17 core samples, as keys to insights about internal processes occurring during the emplacement of the landslide.
Temporal and Spatial Variations in Subterranean Estuary Geochemical Gradients and Nutrient Cycling Rates: Impacts on Groundwater Nutrient Export to Estuaries
Authors: Wilson Stephanie J. , Anderson Iris C. , Song Bongkeun , Tobias Craig R. 
Published: May 2023

AbstractSubterranean estuaries (STEs) form at the land‐sea boundary where groundwater and seawater mix. These biogeochemically reactive zones influence groundwater‐borne nutrient concentrations and speciation prior to export via submarine groundwater discharge (SGD). We examined a STE located along the York River Estuary (YRE) to determine if SGD delivers dissolved inorganic nitrogen (DIN) and phosphorus (DIP) to the overlying water. We assessed variations in STE geochemical profiles with depth across locations, times, and tidal stages, estimated N removal along the STE flow path, measured hydraulic gradients to estimate SGD, and calculated potential nutrient fluxes. Salinity, dissolved oxygen (DO), DIN, and DIP varied significantly with depth and season (p < 0.05), but not location or tidal stage. Ammonium dominated the DIN pool deep in the STE. Moving toward the sediment surface, ammonium concentrations decreased as nitrate and DO concentrations increased, suggesting nitrification. Potential sediment N removal rates mediated by denitrification were <8 mmoles N m−2 d−1. The total groundwater discharge rate was 38 ± 11 L m−2 d−1; discharge followed tidal and seasonal patterns. Net SGD nutrient fluxes were 0.065–3.2 and 0.019–0.093 mmoles m−2 d−1 for DIN and DIP, respectively. However, microbial N removal in the STE may attenuate 0.58% to >100% of groundwater DIN. SGD fluxes were on the same order of magnitude as diffusive benthic fluxes but accounted for <10% of the nutrients delivered by fluvial advection in the YRE. Our results indicate the importance of STE biogeochemical transformations to SGD flux estimations and their role in coastal eutrophication and nutrient dynamics.
Acceleration of the Parameterization of Unified Microphysics Across Scales (PUMAS) on the Graphics Processing Unit (GPU) With Directive‐Based Methods
Authors: Sun Jian , Dennis John M. , Mickelson Sheri A. , Vanderwende Brian , Gettelman Andrew , Thayer‐Calder Katherine 
Published: May 2023

AbstractCloud microphysics is one of the most time‐consuming components in a climate model. In this study, we port the cloud microphysics parameterization in the Community Atmosphere Model (CAM), known as Parameterization of Unified Microphysics Across Scales (PUMAS), from CPU to GPU to seek a computational speedup. The directive‐based methods (OpenACC and OpenMP target offload) are determined as the best fit specifically for our development practices, which enable a single version of source code to run either on the CPU or GPU, and yield a better portability and maintainability. Their performance is first examined in a PUMAS stand‐alone kernel and the directive‐based methods can outperform a CPU node as long as there is enough computational burden on the GPU. A consistent behavior is observed when we run PUMAS on the GPU in a practical CAM simulation. A 3.6× speedup of the PUMAS execution time, including data movement between CPU and GPU, is achieved at a coarse horizontal resolution (8 NVIDIA V100 GPUs against 36 Intel Skylake CPU cores). This speedup further increases up to 5.4× at a high resolution (24 NVIDIA V100 GPUs against 108 Intel Skylake CPU cores), which highlights the fact that GPU favors larger problem size. This study demonstrates that using GPU in a CAM simulation can save noticeable computational costs even with a small portion of code being GPU‐enabled. Therefore, we are encouraged to port more parameterizations to GPU to take advantage of its computational benefit.