Conditions For Occurrence Research Articles

Step-by-step silicon carbide graphitisation process study in terms of time and temperature parameters

This work investigates the temperature and time as key parameters for graphene formation on the silicon carbide surface during the high thermal decomposition process. Measurements were performed using various experimental techniques under ultra-high vacuum conditions. The graphitisation process was divided into various stages, after which the surface chemical composition and atomic structures were analysed in detail. It has been shown that despite the known theory of graphitisation mechanism and initial condition for occurrence of this process, the application of different temperatures and heating times affect the quality and quantity of formed graphene layers. Applying a temperature too low or annealing the sample for a too short time led to an inefficient silicon sublimation process. On the other hand, too high temperature during flashing modifies the visibility of surface structures, which may be crucial for other investigations and potential applications of such systems.

Exploration of the Conditions for Occurrence of Photoplethysmographic Signal Inversion above the Dorsalis Pedis Artery.

Inversion of the photoplethysmographic (PPG) signal is a rarely reported case. This signal anomaly can have implications for PPG-based cardiovascular assessments. The conditions for PPG signal inversion in the vicinity of the dorsalis pedis (DPA) artery of the foot were investigated. Wireless multi-wavelength PPG sensing with skin-probe contact pressure and local skin temperature were studied at different sensor positions, and the occurrence of inversion (OOI) was investigated. Twelve healthy adult volunteers were studied over four LED wavelengths at three levels of contact pressure for 11 probe positions. A novel algorithm quantified the proportion of inverted samples with respect to the abovementioned variables. Our algorithm classifying inverted vs. non-inverted pulses achieved 98.3% accuracy. Ten of the participants had at least one inverted signal identified. The impact of interindividual variation on inversion prevalence was large, but different LEDs, relative position to the DPA and sensor contact pressure also affected OOI. Skin surface and room temperatures showed no impact on OOI. Lateral measurements showed 39.6% more inversion at maximum compared to minimum contact pressure. Mechanical capillary bed variations and arterial reflections during venous engorgement are considered viable explanations for our observations. These findings motivate an expanded study of the occurrence of PPG signal inversion.

Reclaiming Calcicoles: New Insights into Lime Lovers

Calcicoles are never new to the evolutionary life forms in the ecological world. The ramifications of environmental extremes always facilitate the emergence of the functional and structural integrity of plants and calcicoles, which have been exuding through this. The word “calcicole” finds its roots in the writings of Nathaniel Colgan, “The Orchids of Country Dublin,” published in August 1895 in “The Irish Naturalist.” Calcicoles are likely to flourish under calcium-rich soil having a pH of more than five, which otherwise hinders the growth of plant species, causing detrimental effects on their physiology. They are often regarded as lime lovers or acidofuges and are classified based on Ca2+ stress resistance, soluble and insoluble Ca2+ and Mg2+, pH conditions of soil, occurrence, and habitat. There are various variables used to evaluate the calcicoles described in this review, such as the Index of calcifugy, Ellenberg’s indicator values, and Landolt indicator values to predict the influence of environmental factors in determining flora along with changes in vegetation in a particular area considering the ecophysiological or morphological features. Calcicoles have specific in-built mechanisms to cope with stress conditions by producing phytosiderophores (PS) and by involving ecto and ericoid mycorrhizal associations for the absorption of iron and phosphorus, and high control over cytosolic Ca2+ concentrations. Calcicoles are markedly distributed in various plant families like Asteraceae, Brassicaceae, Amaranthaceae, Caryophyllaceae, Ericaceae, Primulaceae, Fabaceae, Gentianaceae, Rubiaceae, Plantaginaceae, Poaceae, Saxifragaceae, etc. The current review focuses on the ecological perspectives, special adaptive features, and phytopharmacological aspects of calcicoles.

Integrating hydrological parameters in wildfire risk assessment: a machine learning approach for mapping wildfire probability

Abstract The increasing occurrence of catastrophic wildfire across the globe threatens public health, community safety, ecosystem functioning, and biodiversity resilience. Wildfire risk is closely connected to shifting climatic trends and their impacts on fuel availability and flammability. Although previous research has explored the connection between meteorological conditions and wildfire probabilities, there remains a substantial gap in understanding the influence of hydrologic drivers, such as groundwater recharge, on wildfire dynamics. Both short- and long-term variations in these variables are crucial in shaping fuel conditions, and significant changes can create environments more prone to severe wildfires. This study focuses on Santa Barbara County to examine the connection between wildfire probability and various environmental factors, including meteorological and hydrological data from 1994 to 2021, topography, vegetation, and proximity to road. Using a random forest (RF) machine learning model and fine-scale data (270 m resolution) we achieved high predictive accuracy in identifying wildfire probability. Our findings confirm the important roles of short-term meteorological conditions, such as mean precipitation 12 months and relative humidity 1 month before a wildfire event, in predicting wildfire occurrence. In addition, our results emphasize the critical contribution of long-term hydrological components, such as mean deviation from the historical normal in actual evapotranspiration and recharge in the years preceding the fire, in influencing wildfire probability. Partial dependence plots from our RF model revealed that both positive and negative deviations of these hydrological variables can increase the likelihood of wildfire by controlling fuel water availability and productivity. These findings are particularly relevant given the increasing extreme weather patterns in southern California, significantly affecting water availability and fuel conditions. This study provides valuable insights into the complex interactions between wildfire occurrence and hydrometeorological conditions. Additionally, the resulting wildfire probability map, can aid in identifying high-risk areas, contributing to enhanced mitigation planning and prevention strategies.

Increasing the reliability of oil and gas well fastening with polycomponent plugging systems

Purpose. Development of effective composite plugging systems for reliable fastening of oil and gas wells in difficult mining-geological conditions of deposits of Ukraine. Methods. The proposed research is based on an analytical and industrial study of the problems of the well construction and fastening in the conditions of chemogenic deposit occurrence when applying the analysis of geophysical research materials. The research of tamponage solutions and buffer liquids was carried out using standard devices and methods that meet the set of requirements for testing cements and technological systems for well construction. Processing of research results was carried out in MATHSAD and EXCEL. Composite cement CEM V according to the European standard EN 197-1, tamponage cement 1-G, krents - high-basic C2F CaSO4 and low-basic 3(CF) CaSO4 calcium sulfoferites were used for the research. Findings. It was established that the basic plugging material, as well as technological solutions for fastening wells in difficult mining-geological conditions, do not ensure compliance of the well as an engineering structure with operational reliability indicators. As a result, violations in the fastening system are quite often recorded, which require significant time and financial costs for their elimination, and sometimes lead to well liquidation. In order to increase the reliability of fastening wells, it is necessary to use multi-component tamponade systems modified by krents. Calcium sulfoferrite admixtures have been proved to accelerate the kinetics of early strength and contribute to the formation of cement stone with improved characteristics. The need to use effective buffer systems to improve the quality of fastening is substantiated. Originality. On the basis of assessment, systematization and detailed study of geophysical material and features of well fastening under the conditions of exposure to chemogenic sediments, the necessity of using composite plugging material was established. The conducted studies have proved that to ensure reliable fastening of wells in difficult mining-geological conditions, it is necessary to use multicomponent composite plugging material modified by calcium sulfoferites with accelerated kinetics of early strength, which form cement stone with a densely packed structure. Practical implications. Based on the industrial material evaluation and detailed laboratory studies, technological solutions have been developed to increase the reliability of well fastening due to the introduction of multi-component composite plugging material modified by krents and buffer liquids.

The clinical characteristics and risk factors analysis within one week before the onset of necrotizing enterocolitis

There are considerable researches on risk factors for necrotizing enterocolitis (NEC), focusing primarily on the entire course before onset. However, fewer studies address risk factors within the brief period before NEC occurrence. The current study aims to retrospectively analyze the clinical data of NEC patients while focusing on relevant risk factors in the preceding week of NEC onset. Infants born between January 2019 and December 2021 at Suzhou Municipal Hospital and Suzhou University Children’s Hospital with a birth weight < 1500 g or a gestational age < 32 weeks were included. Around 54 NEC patients and 180 controls were recruited in the study. NEC patients satisfying the inclusion criteria formed the case group, while a 1:4 matching principle helped select the control group based on gestational age and birth weight. A statistically significant difference was observed between groups when red blood cell transfusions were compared the week before NEC onset (adjusted OR and 95% CI 2.16 (1.10, 4.24)). Broad-spectrum antibiotic usage before NEC occurrence was significantly lower in the NEC group than in the control group (adjusted OR and 95% CI 0.95 (0.91, 0.99)). A statistically significant difference was observed between groups while comparing patent ductus arteriosus (PDA) (adjusted OR and 95% CI 2.45 (1.23, 4.91)). The indication for packed red blood cell transfusion should be strictly controlled. Moreover, close monitoring of the patient’s condition for NEC occurrence should be conducted within one-week post-transfusion. Accurately identifying infections and using broad-spectrum antibiotics can reduce the incidence of NEC.

Mechanism of Instantaneous High-Strength Sand–Water Inrush in Steeply Inclined Mining of Soft Coal Seam under Disturbed Rock–Soil Overburden

Abstract Water and sand inrush pose significant threats to underground geotechnical engineering, including shallow buried resource extraction and tunnel construction. To understand the mechanisms behind these phenomena, a mud collapse accident in Chaider Coal Mine was comprehensively investigated through field exploration and laboratory-based testings. Using numerical simulation experiments, we analyzed the failure patterns and seepage characteristics of overlying strata in steeply inclined coal seam mining under various working conditions. We established a structural instability model for water and sand inrush and identified the critical conditions for sand collapse occurrence. Our research indicates that the backfill in the surface mining pit provided a substantial material source for the accident. The overall destabilization of the top coal, due to its insufficient thickness and strength, created a pathway for sand collapse. Furthermore, frequent rainfall during the flood season and the inadequate arrangement of pumping equipment acted as triggers for the sudden water collapse. Preventative measures, such as limiting the mining height, enhancing the shear strength of the top coal, and altering the working face layout, can effectively control the development height of the water-conducting fracture zone. Additionally, timely evacuation and lowering of the aquifer water level, weakening its seepage effect in the top coal area, reducing the moisture content of the bottom soil, and improving its shear strength can mitigate water and sand inrush accidents in the backfill areas of open-pit mines.

METHOD FOR ASSESSING THE IMPACT OF GEOLOGICAL HETEROGENEITY ON OIL SATURATION DISTRIBUTION

This article examines a method for assessing the impact of reservoir heterogeneity on the distribution of oil saturation in pay zones using the example of the Bajossian and Bathonian stages of the Jurassic system of the Kalamkas field. Within this field, the Jurassic oil and gas stratum under consideration lies on the eroded surface of various horizons of the Middle and Lower Triassic and is represented by uneven alternation of sand-siltstone and clay rocks, as a result of which these deposits have a complex geological structure, due in the lithological plan to uneven alternation of sand-siltstone and clay rocks. As a result, a rather complex distribution of oil (water) saturation may occur in the formation, which differs from the standard ideas about the geological structure of the object under study, i.e. the presence of such «unconventional» reservoir boundaries (oil-bearing contour) as capillary barriers of the first kind is possible. As a result of this approach, the following is obtained. For the conditions of occurrence of productive formations of the Bajossian stage of the field in question, in order to ensure that the dimensions of the capillary barrier in the reservoir do not exceed the height of 1 m at an average value of the porosity coefficient Kп = 27,6 % it is necessary to fulfill the inequality of Kпр ≥ 6,1∙10−3 μm2. For the conditions of occurrence of productive formations of the Bathonian stage, in order for the dimensions of the capillary barrier in the reservoir not to exceed the height of 1 m with an average value of the porosity coefficient Kп = 28,0 % it is necessary to Kпр ≥ 7,5∙10−3 μm2. Also, on the basis of this method, various ratios of Kпр permeability coefficients and porosity were obtained Kп at which the dimensions of the capillary barrier in the deposit will exceed the heights of 1.0, 1.5 and 2.0 m above the level of the accepted oil-water contact (OWC) for the conditions of occurrence of the Kalamkas field in question. It was noted that this approach makes it possible to assess uncertainties in the position of fluid contacts when justifying the boundaries of the oil potential contour and the distribution of oil reserves in formations with a wide range of reservoir properties.

Sufficient condition for reliable logic operations in an over damped bistable system driven by Gaussian white noise.

In this paper, we investigate an overdamped bistable system subject to Gaussian white noise and logical inputs. By solving and estimating the steady distribution of the corresponding Fokker-Planck equation and considering the two essential features of the reliable logic operations (RLOs)-initial value independence and sign invariance-we establish the sufficient condition for RLO occurrence and identify parametric resonance phenomena in the system. Our numerical simulations confirm the reliability and accuracy of the theoretical results. This work offers insights into enhancing the accuracy of stochastic systems, particularly in the realm of logical stochastic resonance, thereby contributing to advancements in understanding and controlling stochastic dynamical systems.

Estimation of hydrochemical profile and trophic status of a coastal Ramsar site in south west coast of India

Coastal lakes are confronting a spectrum of threats arising from both natural processes and human activities. This study presents an investigation into the nutrient and trophic status of the Ramsar-designated (Ramsar site No. 1204) Ashtamudi Lake (ASL; area= 56 km2), situated along the southwest coast of India. To establish a comprehensive hydrochemical profile, 50 representative water samples comprising lake, surface and bottom layers were systematically collected from 25 distinct sites during the non-monsoon and monsoon seasons of 2017. Physcio-chemical characteristics were evaluated using standard protocols and procedures. The salinity observations consistently position the majority of the lake's area within the 'polyhaline' condition (18–30 PSU) throughout the year. The evaluation of nutrient ratios (DIN/DIP, DSi/DIN, and DSi/DIP) during the respective seasons highlights a prevalent phosphorus (P) and silicon (Si) limited scenario during non-monsoon period. This condition is marked by elevated dissolved inorganic nitrogen (DIN) concentrations juxtaposed with lower levels of dissolved inorganic phosphorus (DIP) and dissolved silicon (DSi). The computed Trophic Index (TRIX) unequivocally denotes a 'hypertrophic' state within the lake during the non-monsoon season. This characterization is upheld by TRIX values of 7.73±0.61 and 8.06±0.62 for surface and bottom water during non-monsoon. Further insight into the TRIX findings is derived from the supplementary Efficiency Coefficient (EF) index, which accentuates ASL's limited nutrient assimilation in conjunction with a substantial input of DIN. Overall, the sustained condition of occurrence of low dissolved oxygen and elevated DIN/DIP ratios exacerbates the hypertrophic state. This complex interplay heightens ecological strain, thereby imperiling aquatic organisms, particularly valuable fishery resources. Unfortunately, this situation invariably curtails the essential ecosystem services furnished by ASL. Therefore, the adoption of strategic interventions aimed at ameliorating nutrient influx and restoring a balanced trophic equilibrium stands imperative to mitigate ecological degradation and uphold the lake's pivotal contributions to its surrounding environment.

Producing a siliceous ferroalloy from a mixture of amorphous rocks

The main silicon-containing component in a charge during ferrosilicon smelting is quartzite. The carbothermic reduction rate of the crystalline structure SiO2 has a limitation associated with a fixed energy reserve of silicon-oxygen bond. The reactive capacity of silica can be increased by using its amorphous form instead of the crystalline SiO2. The amorphous form of silica has a higher dispersion, greater free surface energy, and, consequently, a more active degree of entering into a reaction. Such silica-containing materials include amorphous rocks: diatomite, opoka, tripoli. The article presents the results of experimental studies of electrothermal ferrosilicon production from a mixture of amorphous rocks (tripoli, opoka, diatomite with a mass ratio of 1:1:1).It is established that when smelting the mixture of amorphous rocks containing 77 % SiO2, 7.9 % Al2O3, 5.2 % Σ CaO and MgO, 4 % Σ K2O Na2O, 3.3 % Fe2O3, 1.3 % CaCO3, 0.9 % CaSO4, 0.4 % others, three ferrosilicon grades are formed: FeSi25 (22–29 % Si), FeSi45 (41–47 % Si), FeSi50 (47–52 % Si) with the extraction degree of 70–87.6 % silicon into the alloy. Moreover, the ferrosilicon grade decreases with an increase in steel shavings in the charge from 21.9-31.4 % to 33–35 %. In comparison with ferrosilicon smelting from a standard charge containing quartzite with the crystalline form of SiO2, steel shavings and coke, ferrosilicon production from the mixture of amorphous rocks allows to increase the process rate by 17.5–21.6 %. It is possible to increase the silicon extraction degree into the alloy from 80-85 %–94.5 % if its final stage is carried out in the resistance mode. Widespread occurrence in nature, favorable conditions of occurrence, low cost, high reactive capacity are favorable factors for using amorphous rocks in the production of ferroalloys.

Predicting the climatic suitability of non-native drought resistant trees in the face of desertification – A case study with Argania spinosa in the Iberian Peninsula

Climate change is driving a poleward shift in the optimal distributions of terrestrial organisms, including trees. Consequently, trees are expected to decrease in climatically unfavourable areas as their optimal climatic conditions shift poleward. This is the case of Mediterranean High Nature Value agroforestry systems in Iberian Peninsula, dominated by holm oaks (Quercus rotundifolia) and cork oaks (Quercus suber), which are expected to shift their future distribution northward. Failure to keep pace with climate warming poses a heightened risk of extinction for these tree species, as well as the loss of crucial ecosystem services they provide. A similar situation is found for argan trees (Argania spinosa) in the southwestern region of Morocco, where it also supports an agroforestry system. The optimum climate for these trees is also shifting northward, toward the Iberian Peninsula. As the argan tree thrives in more arid conditions with irregular precipitation, the future climatic conditions in the Iberian Peninsula may become favourable for the persistence of this tree. In light of this situation, the assisted colonization of the argan tree could potentially contribute to protecting and preserving the tree-associated ecosystem services in Iberian Peninsula. We conducted climate suitability modelling using maximum entropy approach, for both the current and future timeframes, for North of Morocco and Algeria (native range) and the whole Iberian Peninsula (non-native range). Accordingly, there appears to be a significant area with highly suitable climatic conditions (>80 %) for argan tree occurrence, covering approximately 6.7 % of the territory, over 38,000 km2. This area is projected to increase significantly in the future, covering 9–22 % of the territory, or about 55,000 and 127,000 km2. With this study, we aim to contribute to the discussion on the benefits of assisted colonization of argan trees into Iberian Peninsula, as well as potential drawbacks such as the risk of this species becoming invasive.

Pattern dynamics of a Lotka-Volterra model with taxis mechanism

This paper deals with the Turing bifurcation and pattern dynamics of a Lotka-Volterra model with the predator-taxis and the homogeneous no-flux boundary conditions. To investigate the pattern dynamics, we first give the occurrence conditions of the Turing bifurcation. It is found that there is no Turing bifurcation when predator-taxis disappears, while the Turing bifurcation occurs as predator-taxis is presented. Next, we establish the amplitude equation by virtue of weakly nonlinear analysis. Our theoretical result suggests the Lotka-Volterra model admits the supercritical or subcritical Turing bifurcation. In this manner, we can determine the stability of the bifurcating solution. Finally, some numerical simulation results verify the validity of the theoretical analysis. The stripe pattern, the mixed patterns, and wave patterns are performed. Interestingly, the stable stripe patterns will be broken and become wave patterns when the predator-taxis parameter is far from the Turing bifurcation critical point.

Analysis of condensation phenomena according to the type of energy recovery ventilator—Simulation and experiments

Ventilation plays a crucial role in maintaining indoor air quality. Energy recovery ventilators (ERVs) have emerged as a solution to balance ventilation needs and energy consumption in buildings. However, ERVs can encounter condensation issues in extreme outdoor conditions, impacting their performance and indoor air quality. In this study, we investigate occurrence conditions and ratios of condensation in ERVs through dynamic simulations and experimental tests using different heat exchanger types: plastic-based plate, membrane-based plate, and rotary. The simulation results show that condensation ratios vary depending on the heat exchanger type and seasonal conditions, with higher latent effectiveness playing a significant role in reducing condensation. Notably, we demonstrate that rotary ERVs rarely exhibit the generation of condensation. The simulation results are validated through experimental tests, ensuring reliable condensation predictions in ERVs. Our findings underline the importance of selecting appropriate type of ERV to mitigate condensation and enhance indoor comfort while promoting energy efficiency. The proposed simulation methodology will provide valuable insights into estimating condensation ratios in ERVs under diverse climatic conditions.

Electro-optical effect of unpolarized light modulation in homeoplanar structures of ferroelectric and ferrielectric liquid crystals.

A clearly expressed effect of unpolarized light electro-optical modulation by homeoplanar structures of a smectic C* ferroelectric liquid crystal (FLC) and a ferrielectric liquid crystal (FerriLC) was discovered and investigated for the first time to our knowledge. This effect of electrically controlled light scattering is insensitive to the applied voltage sign, as for polymer-dispersed nematic liquid crystals (PDLCs), but the electro-optical modulation frequency reaches the kilohertz range. Occurrence conditions and essential features of the effect, as well as its physical origin, are discussed.

Occurrence characteristics and enrichment mechanism of cobalt in pyrite from the Han‐Xing type skarn iron deposit using laser‐ablation inductively‐coupled‐plasma mass‐spectrometry elemental mapping, Taihang Mountain, China

Cobalt is a critical and strategic metal mainly found as associated element in several types of deposits, of which skarn‐type deposits are the major sources. Han‐Xing type skarn iron deposit, having high grade iron ore and associated cobalt, is a typical skarn‐type iron ore in China. But the complete recovery and exploitation of cobalt are restricted because of the lower grade of related cobalt and the dearth of prior research on its occurrence condition and enrichment mechanism. In this paper, pyrite from five typical ore deposits in the Han‐Xing area was studied by using electron probe microanalysis (EPMA) and laser‐ablation inductively‐coupled‐plasma mass‐spectrometry (LA–ICP–MS) techniques to decipher the occurrence state and enrichment mechanism of associated cobalt in skarn‐type iron deposits. The results show that Co2+ replaces Fe2+ in pyrite through isomorphism. The distribution of cobalt in pyrite from different deposits varies greatly, that is, in the Xishimen iron deposit, the cobalt content is comparatively enriched in the pyrite's core. In contrast, in other deposits, the cobalt content is concentrated in the pyrite's rims, where it can be up to 1000 times higher than in the core. The cobalt mineralization in Han‐Xing area can be divided into several stages. The sulphur element of sulphide is mainly derived from evaporite, while cobalt mineralization occurred in the early stage with pyrite formation or in the late stage by metasomatism/cementation of Co‐rich ore‐forming fluid. The magma assimilated with the Ordovician evaporite not only promoted iron mineralization, but also became the main controlling factor for cobalt enrichment.

Study on dynamic mechanical properties and microscopic damage mechanisms of granite after dynamic triaxial compression and thermal treatment

As underground mining operations gradually extend deeper, the conditions for orebody occurrence become increasingly complex, and various geological disasters occur frequently. Rock masses are prone to different degrees and types of damage, making it impractical to continue using intact rock as a reference. To study the dynamic mechanical properties of damaged rock under actual conditions, this study subjected granite samples to impact and high-temperature damage. Detailed observations were made of the samples' surface morphology and microstructure before and after damage, and the patterns of damage changes were investigated. Subsequently, uniaxial compression tests at different loading rates were conducted on the damaged samples. By calculating the loading rate effect sensitivity, it was found that as the damage increased, the rate effect gradually diminished. In addition, this study also summarized the influence of damage and loading rate on the macroscopic failure characteristics of the samples. The novelty of this study lies in focusing on damaged rock, which more closely resembles the actual rock conditions encountered in most underground mining operations today. This research can provide a reference for stability assessment and safe construction in deep mining rock engineering and offers important insights into the feasibility of non-explosive extraction of damaged rock.

The Application of Remote Sensing Technology in Post-Disaster Emergency Investigations of Debris Flows: A Case Study of the Shuimo Catchment in the Bailong River, China

The Bailongjiang River Basin is a high-risk area for debris flow in China. On 17 August 2020, a debris flow occurred in the Shuimo catchment, Wen County, which blocked the Baishui River, forming a barrier lake and causing significant casualties and property damage. In this study, remote sensing, InSAR, field surveys, and unmanned aerial vehicle (UAV) techniques were used to analyze the causal characteristics, material source characteristics, dynamic processes, and disaster characteristics after the debris flow. The results showed that the Shuimo catchment belongs to low-frequency debris flows, with a recurrence cycle of more than 100 years and concealed features. High vegetation coverage (72%) and a long main channel (11.49 km) increase the rainfall-triggering conditions for debris flow occurrence, making it more hidden and less noticed. The Shuimo catchment has a large drainage area of 31.26 km2, 15 tributaries, significant elevation differences of 2017 m, and favorable hydraulic conditions for debris flow. The main sources of debris flow material supply are channel erosion and slope erosion, which account for 84.4% of the total material. The collapse of landslides blocking both sides of the main channel resulted in an amplification of the debris flow scale, leading to the blockage of the Baishui River. The scale of the accumulation fan is 28 × 104 m3, and the barrier lake area is 37.4 × 104 m2. The formation mechanism can be summarized as follows: rainfall triggering → shallow landslides → slope debris flow → channel erosion → landslide damming → dam failure and increased discharge → deposition and river blockage. The results of this study provide references for remote sensing emergency investigation and analysis of similar low-frequency and concealed debris flows, as well as a scientific basis for local disaster prevention and reduction.

Analysis method of point defects evolution in fused silica under multi-pulse nanosecond laser irradiation

Although no optically visible damage is produced in the fused silica under laser irradiation below its laser-induced damage threshold (LIDT), defect proliferation may occur due to the evolution of its internal atomic structure. The escalation in defect content leads to heightened absorption, and resulting in the degradation of the optical performance of the optics. In recent decades, there have been a lot of experimental studies on laser-induced damage and laser conditioning, but there is still a great lack of in-depth understanding and theoretical analysis of the evolution process of point defects in fused silica. In this study, the emphasis is on the evolution of point defects and fatigue damage in fused silica under multi-pulse nanosecond laser irradiation. To address this, a point-defect evolution model is developed, and the coupled evolution law of temperature and defect during laser irradiation is derived by integrating it with a numerical model. The results demonstrate that the model effectively predicts the defect evolution of fused silica under laser irradiation and facilitates the prediction of fatigue damage. It is revealed that the rate of defect evolution in fused silica is more influenced by temperature than stress, and a temperature threshold can be used to judge the condition of damage occurrence. Furthermore, through an analysis of the effect of laser fluence on defect relaxation rate, a defect relaxation method employing variable laser fluence was proposed. This study provides a reliable theoretical analysis method for understanding the fatigue damage induced by multi-pulse laser irradiation in fused silica and offers a new perspective for the annealing treatment of point defects in fused silica.

Prediction of Anthracnose Risk in Large-Leaf Tea Trees Based on the Atmospheric Environmental Changes in Yunnan Tea Gardens—Cox Regression Model and Machine Learning Model

Crop diseases pose a major threat to agricultural production, quality, and sustainable development, highlighting the importance of early disease risk prediction for effective disease control. Tea anthracnose can easily occur in Yunnan under high-temperature and high-humidity environments, which seriously affects the ecosystem of tea gardens. Therefore, the establishment of accurate, non-destructive, and rapid prediction models has a positive impact on the conservation of biodiversity in tea plantations. Because of the linear relationship between disease occurrence and environmental conditions, the growing environmental conditions can be effectively used to predict crop diseases. Based on the climate data collected by Internet of Things devices, this study uses LASSO-COX-NOMOGRAM to analyze the expression of tea anthracrum to different degrees through Limma difference analysis, and it combines Cox single-factor analysis to study the influence mechanism of climate and environmental change on tea anthracrum. Modeling factors were screened by LASSO regression, 10-fold cross-validation and Cox multi-factor analysis were used to establish the basis of the model, the nomogram prediction model was constructed, and a Shiny- and DynNOM-visualized prediction system was built. The experimental results showed that the AUC values of the model were 0.745 and 0.731 in the training set and 0.75 and 0.747 in the verification set, respectively, when the predicted change in tea anthracnose disease risk was greater than 30% and 60%, and the calibration curve was in good agreement with the ideal curve. The accuracy of external verification was 83.3% for predicting tea anthracnose of different degrees. At the same time, compared with the traditional prediction method, the method is not affected by the difference in leaf background, which provides research potential for early prevention and phenotypic analysis, and also provides an effective means for tea disease identification and harm analysis.