Due to the various shapes, textures, and colors of fires, forest fire detection is a challenging task. The traditional image processing method relies heavily on manmade features, which is not ...universally applicable to all forest scenarios. In order to solve this problem, the deep learning technology is applied to learn and extract features of forest fires adaptively. However, the limited learning and perception ability of individual learners is not sufficient to make them perform well in complex tasks. Furthermore, learners tend to focus too much on local information, namely ground truth, but ignore global information, which may lead to false positives. In this paper, a novel ensemble learning method is proposed to detect forest fires in different scenarios. Firstly, two individual learners Yolov5 and EfficientDet are integrated to accomplish fire detection process. Secondly, another individual learner EfficientNet is responsible for learning global information to avoid false positives. Finally, detection results are made based on the decisions of three learners. Experiments on our dataset show that the proposed method improves detection performance by 2.5% to 10.9%, and decreases false positives by 51.3%, without any extra latency.
•Pregelatinized starch (IPS) was prepared by Improved Extrusion Cooking Technology.•IPS had improved solubility, gel stability & lower short-term retrogradation rate.•The chains near or at the ...branching points were degraded during IECT process.•Functional properties were explained in terms of changes in starch structure.
Pregelatinized starch was made from indica rice starch using a so-called “improved extrusion cooking technology” (IECT) under 30%–70% moisture content. IECT-pregelatinized starch (IPS) had higher water solubility and water absorbability compared to native starch at low temperature. For pasting properties, the breakdown and setback viscosities of IPS were significantly (p<0.05) lower than native starch, suggesting improved gel stability and reduced short-term retrogradation. The rice starch granules lost their integrity in IPS, and formed a honeycomb-like structure with increased moisture content in the raw material. These properties can be explained in terms of molecular structural features, particularly the large reduction in the size of molecules, but without significant changes in the chain-length distributions of amylopectin component, and no significant change in amylose fraction. These results indicate that IECT is suitable for preparing IPS with desirable water solubility and gel stability properties.
In this article, the nonlinear dynamic responses of sandwich functionally graded (FG) porous cylindrical shell embedded in elastic media are investigated. The shell studied here consists of three ...layers, of which the outer and inner skins are made of solid metal, while the core is FG porous metal foam. Partial differential equations are derived by utilizing the improved Donnell’s nonlinear shell theory and Hamilton’s principle. Afterwards, the Galerkin method is used to transform the governing equations into nonlinear ordinary differential equations, and an approximate analytical solution is obtained by using the multiple scales method. The effects of various system parameters, specifically, the radial load, core thickness, foam type, foam coefficient, structure damping, and Winkler-Pasternak foundation parameters on nonlinear internal resonance of the sandwich FG porous thin shells are evaluated.
Lead-free (1−x)(0.75Bi0.5Na0.5TiO3–0.25Bi0.5K0.5TiO3)–xBiAlO3 (BNT–BKT–100xBA, x=0–0.10) ceramics were prepared by two-step sintering method and their phase structure, micro morphology and electrical ...properties were systematically investigated. X-ray diffraction analysis indicates a pure perovskite phase for x≤0.06 as well as a structural evolution from a tetragonal toward a pseudocubic phase. Transmission electron microscopy study of the x=0.04 composition reveals the existence of antiferroelectric phase with a0a0c+ oxygen octahedron tilting which is in the form of nano-domains. Polarization-electric field and current-electric field hysteresis loops demonstrate that the increase of BA concentration destroys the ferroelectric order and strengthens antiferroelectric order. A much enhanced energy storage density of 1.15J/cm3 and efficiency of 73.2% is achieved under 105kV/cm at x=0.06. In addition, its energy storage property is found to depend weakly on temperature within the measurement range of 25–150°C.
In this research, the vibration and buckling of three-dimensional graphene foam (3D-GrF) microshells are investigated for the first time. In the microshells, three-dimensional graphene foams can ...distribute uniformly or non-uniformly through the thickness direction. Based on Love's thin shell theory and the modified couple stress theory (MCST), size-dependent governing equations and corresponding boundary conditions are established through Hamilton's principle. Then, vibration and axial buckling of 3D-GrF microshells are analyzed by employing the Navier method and Galerkin method. Results show that the graphene foam distribution type, size effect, the foam coefficient, the radius-to-thickness ratio, and the length-to-radius ratio play important roles in the mechanical characteristics of 3D-GrF microshells.
AISI 420 martensitic stainless steel with excellent corrosion resistance is an ideal choice for plastic injection molds. However, injection molds are easy to fail in high–intensity and high-pressure ...environments. Therefore, it's necessary to improve their hardness and tensile strength to prolong the service life of injection molds. In this work, Selective laser melting (SLM), an additive manufacturing technology was utilized to process 5 wt% TiC/AISI 420 composites. The influence of volumetric energy density (η) on relative density, constitutional phases, microstructure and mechanical properties were investigated. The results indicated that insufficient energy input could cause defects such as pores and crack in the parts, while a part with near-full density could be fabricated if the applied η was properly settled. The ring-like structure that was comprised of thin “metal-ceramic” interface along the grain boundary was distributed more uniform with the increase of applied η. The SLM-processed sample showed a best mechanical properties at highly applied η (320 W, 850 mm/s, η = 85.6 J/mm3). It had an elevated micro-hardness (592.2 ± 53.6 Hv), an enhanced tensile strength (1452.5 MPa) and an improved elongation (8.65%), which was higher than that of the cast AISI 420 stainless steel. The research would provide theoretical support for the application of SLM-processed AISI420 stainless steel composites.
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•SLM was utilized to fabricate TiC/AISI420 composites with various volumetric energy densities.•The ring-like TiC reinforcement were distributed more uniform as the volumetric energy density increased.•A novel microstructure that obtained from samples contributed to the grains refining and grain boundaries strengthening.•The SLM-processed TiC/AISI420 composites showed superior mechanical properties.
Acute hepatopancreatic necrosis disease (AHPND) is a newly emerging shrimp disease caused by pirAB toxins encoded by a plasmid found in Vibrio parahaemolyticus. The pirAB toxins are the homologs of ...the Photorhabdus insect-related (Pir) toxins. Here, we report the complete sequences of the AHPND-causing plasmid isolated from V. owensii, as well as those of its 11 siblings (pVH family). In addition, we also included 13 related plasmids (pVH-r family) without the pirAB genes isolated from a variety of species within the Vibrio Harveyi clade. Furthermore, the pirAB-Tn903 composite transposon was identified in pVH, and both ends of the transposon appeared to have inserted simultaneously into the ancestor plasmid at different sites. The homologue counterparts of pirAB were also detected in a non-pVH plasmid in V. campbellii. Taken together, our results provide novel insights into the acquisition and evolution of pirAB as well as related plasmids in the Vibrio Harveyi clade.
Thanks to its high transparency, high carrier mobility, and thermal conductivity, graphene is often used as transparent conductive electrode (TCE) in optoelectronic devices. However, the low carrier ...concentration and high resistance caused by vacancy defects, grain boundaries, and superposed folds in typical graphene films limit its application. In this study, we propose a method to increase both the conductivity and carrier concentration in single-layer graphene (SLG) by blending it with silver nanowires (AgNWs). AgNWs provide connections between grain boundaries of graphene to improve charge-carrier transport. The AgNWs in this study can reduce the resistance of SLG from 650 Ω/◻ to 27 Ω/◻ yet still maintain a transmittance of 86.7% (at 550 nm). Flexible organic light-emitting diode, with a maximum 15000 cd m
luminance was successfully fabricated using such graphene and AgNWs composite transparent electrodes.
This study aimed to reveal the effect of corn oil on formation of complex between rice starch and fatty acids, including lauric acid (C12:0), myristic acid (C14:0), palmitic acid (C16:0) and stearic ...acid (C18:0). The RVA, XRD, DSC and CLSM analysis confirmed formation of starch-fatty acid complex but the starch-triglyceride complex was not detected. The addition of triglyceride promoted formation of starch-C16:0 and starch-C18:0 complexes, which might be due to more leached amylose induced by oil. However, triglyceride inhibited formation of starch-C12:0 and starch-C14:0 complexes, which might be due to high solubility of C12:0 and C14:0 in oil. In conclusion, the effect of triglyceride on formation of starch-fatty acid complex depended on the chain length of fatty acids.
•Starch-C12:0, starch-C14:0, starch-C16:0 and starch-C18:0 complexes were formed.•The starch-triglyceride complex was not detected by XRD, DSC and CLSM.•Triglyceride promoted formation of starch-C16:0 and starch-C18:0 complexes.•Triglyceride inhibited formation of starch-C12:0 and starch-C14:0 complexes.
Crop sap flow is a critical indicator of crop water demand, and predicting its variation trend is essential for adjusting agricultural planting structure and managing water resource in hyper-arid ...areas. Presently, research on crop sap flow in hyper-arid areas faces limitations due to inadequate meteorological data and restricted monitoring duration, leading to imprecise assessments of environmental impacts on future crop sap flow. Consequently, this hinders effective irrigation scheduling and oasis sustainable development policy. This study analyzed the sap flow changes characteristics of two economic crops (red jujube and walnut) at different time scales in the oasis in the south of Tarim Basin from 2017 to 2021 and the relationship between four environmental factors (solar radiation, temperature, relative humidity and vapor pressure deficit) and the sap flow of red jujube and walnut. By using the Random Forest (RF) model and the future climate data, the sap flow of the two economic crops from 2020 to 2100 was predicted. The results showed that: (1) walnut had a longer daily peak sap flow duration compared to red jujube, whereas red jujube showed a longer monthly peak sap flow duration; (2) in hyper-arid areas, the moisture and temperature directly influenced crop sap flow, while other environmental factor affected these two factors; (3) with the temperature increases, the water demand of red jujube and walnut in Cele Oasis will exceed local water resources carrying capacity. To achieve sustainable development of oasis, it is vital to consider future climatic changes in planning the expansion and crop structure.
•Crop sap flow data can be used to improve irrigation efficiency.•Moisture and temperature crucially impact crop sap flow in hyper-arid areas.•Warming-induced crop water demand rise threatens oasis sustainability.
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