768 research outputs found

    A Fuzzy-Interval Dynamic Optimization Model for Regional Water Resources Allocation under Uncertainty

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    In this study, a fuzzy-interval dynamic programming (FIDP) model is proposed for regional water management under uncertainty by combining fuzzy-interval linear programming (FILP) and dynamic programming (DP). This model can not only tackle uncertainties presented as intervals, but also consider the dynamic characteristics in the allocation process for water resources. Meanwhile, the overall satisfaction from users is considered in the objective function to solve the conflict caused by uneven distribution of resources. The FIDP model is then applied to the case study in terms of water resources allocation under uncertainty and dynamics for the City of Handan in Hebei Province, China. The obtained solutions can provide detailed allocation schemes and water shortage rates at different stages. The calculated comprehensive benefits of economy, water users’ satisfaction and pollutant discharge (i.e., COD) are [2264.72, 2989.33] × 108 yuan, [87.50, 96.50] % and [1.23, 1.65] × 108 kg respectively with a plausibility degree (i.e., λ±opt) ranging within [0.985, 0.993]. Moreover, the benefit from FIDP model under consideration of dynamic features is more specific and accurate than that of FILP model, whilst the water shortage rate from FIDP is [5.10, 9.10] % lower than that of FILP model.This research was supported by Nation Natural Science Foundation of China (61873084), and Natural Science Foundation of Hebei, in China (D2019402235)

    Experimental Investigation on the Tensile Strength of Composite Laminates Containing Open and Filled Holes

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    An experimental study is performed to evaluate the effects of clamping pressure, friction, and washer size on the static performance of composite laminates with open and bolt-filled holes. The static tensile strength and failure behavior of composite laminates with an open hole and a bolt-filled hole are analyzed and compared. Experimental results show that the static tensile strength of composite laminates is sensitive to pre-existing damage of both open- or filled-hole laminates. In contrast, a comparison between the experimental results of open- and filled-hole specimens proved that whether the hole is open or filled has a feeble influence on the tensile-tensile fatigue strength of studied composite laminates. In comparison, however, it is found that the inserted washer size, bolt clamping force, and friction force strongly affect the tensile strength of open- and filled-hole composite laminates. Moreover, application of thicker washers and hi-lock bolt will significantly increase the static strength and fatigue life of composite laminates with a bolt-filled hole.Экспериментально оценено влияние силы зажима, трения и размера шайбы на статические характеристики слоистых композитов со сквозными и болтовыми отверстиями. Проведено сравнение статического предела прочности при растяжении и характера разрушения слоистых композитов со сквозным и болтовым отверстиями. Результаты экспериментальных исследований показали, что на статический предел прочности при растяжении слоистых композитов влияет изначальное повреждение независимо от наличия сквозного или болтового отверстия. Сравнительный анализ результатов исследований образцов со сквозным и болтовым отверстиями подтвердил тот факт, что вид отверстия (сквозное или болтовое) незначительно влияет на усталостную прочность при растяжении исследуемых слоистых композитов. Установлено, что такие факторы, как размер шайбы, сила зажима болта и сила трения, существенно влияют на предел прочности при растяжении слоистых композитов со сквозным или болтовым отверстием. Использование утолщенных шайб между слоистым материалом и болтом-заклепкой значительно увеличивает статическую прочность и долговечность слоистых композитов с болтовыми отверстиями.Експериментально досліджено вплив сили затиску, тертя і розміру шайби на статичні характеристики шаруватих композитів із наскрізними і болтовими отворами. Проведено порівняння статичної границі міцності при розтязі і характера руйнування шаруватих композитів із наскрізними і болтовими отворами. Результати експериментальних досліджень показали, що на статичну границю міцності при розтязі шаруватих композитів впливає початкове пошкодження незалежно від наявності наскрізного чи болтового отвору. Порівняльний аналіз результатів досліджень зразків із наскрізними і болтовими отворами підтвердив той факт, що вид отвору (наскрізне чи болтове) незначно впливає на міцність від утомленості при розтязі досліджуваних шаруватих композитів. Установлено, що такі чинники, як розмір шайби, сила затиску болта і сила тертя, суттєво впливають на границю міцності при розтязі шаруватих композитів із наскрізним чи болтовим отвором. Використання стовщених шайб між шаруватим матеріалом і болтом-заклепкою значно збільшує статичну міцність і довговічність шаруватих композитів із болтовими отворам

    Physiological responses of Porphyra haitanesis to different copper and zinc concentrations

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    No presente estudo foram investigadas as respostas fisiológicas da alga vermelha Porphyra haitanesis às elevadas concentrações de cobre (acima de 50 μM) e de zinco (acima de 100 μM). Os resultados mostram que os efeitos de Cu2+ e Zn2+ sobre o crescimento, pigmentos fotossintéticos (clorofilas e carotenóides), ficobiliproteína e metabolismo (o espectro de emissão de fluorescência e as atividades do fotossistema) não seguem o mesmo padrão. A taxa de crescimento relativo foi inibida por diferentes concentrações de Cu2+ e, em presença de Zn2+, aumentou ligeiramente em baixas concentrações (abaixo de 10 μM) e foi inibida em altas concentrações. Por outro lado, os teores de ficoeritrina apresentaram leve aumento em concentrações relativamente baixas de Cu2+ e Zn2+ (até 1 μM Cu2+ e até 20 μM Zn2+, respectivamente) e foram inibidas por altas concentrações. Além disso, tanto a fotossíntese quanto a respiração mostraram aumento nas trocas de oxigênio em resposta às concentrações relativamente baixas de Cu2+ (até 1 μM) e de Zn2+ (até 10 μM), além da redução em concentrações relativamente altas desses metais. Adicionalmente, as atividades fotoredutoras e as emissões de fluorescência do fotossistema II (PSII) foram incrementadas em baixas concentrações de Cu2+ (até 0,1 μM) e de Zn2+ (até 10 μM) e inibidas por altas concentrações. Desta forma, a intensidade da fluorescência da clorofila-a e dos centros de reação ativa PSII seguiram um padrão semelhante em resposta às elevadas concentrações de Cu2+ e Zn2+. Esses resultados sugerem que baixas concentrações de Cu2+ e Zn2+ afetam o metabolismo de P. haitanesis, que se torna inibido por altas concentrações desses metais.In the present study, several physiological responses of the red marine alga Porphyra haitanesis to elevated concentrations of copper (up to 50 μM) and zinc (up to 100 μM) were investigated. Our results showed that the effects of Cu2+ and Zn2+ on growth, photosynthetic pigments (chlorophylls and carotenoids), phycobiliprotein and metabolism (the fluorescence emission spectra and the activities of photosystemII) did not follow the same pattern. The relative growth rate was inhibited by different concentrations of Cu2+, and was slightly increased at lower concentrations (up to 10 μM) and inhibited at higher Zn2+concentrations. On the other hand, the phycoerythrin contents were slightly increased at relatively low concentrations (up to 1 μM Cu2+ or 20 μM Zn2+) and inhibited by high Cu2+ and Zn2+ concentrations. Moreover, photosynthesis and respiration showed an increase in the amount of oxygen exchange in response to relatively low Cu2+ (up to 1 μM) and Zn2+ concentrations (up to 10 μM), and a reduction to relatively high Cu2+ and Zn2+ concentrations. Oxygen evolution was more sensitive than oxygen uptake to Cu2+ and Zn2+. In addition, the photoreductive activities and fluorescence emission of photosystem II (PS II) were enhanced by lower concentrations of Cu2+ (up to 0.1 μM) and Zn2+ (up to 10 μM) and inhibited by higher concentrations. Furthermore, the intensity of chlorophyll a fluorescence and the active PSII reaction centers followed a similar pattern in response to elevated concentrations of Cu2+ and Zn2+. These results suggest that lower concentrations of Cu2+ and Zn2+ affected the metabolism of P. haitanesis, which was inhibited by higher concentrations of these metals

    Rapid appearance quality of rice based on machine vision and convolutional neural network research on automatic detection system

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    IntroductionIn the process of rice production and storage, there are many defects in the traditional detection methods of rice appearance quality, but using modern high-precision instruments to detect the appearance quality of rice has gradually developed into a new research trend at home and abroad with the development of agricultural artificial intelligence.MethodsIn this study, we independently designed a fast automatic rice appearance quality detection system based on machine vision technology by introducing convolutional neural network and image processing technology. In this study, NIR and RGB images were generated into five-channel image data by superposition function, and image are preprocessed by combining the Watershed algorithm with the Otus adaptive threshold function. Different grains in the samples were labeled and put in the convolutional neural network for training. The rice grains were classified and the phenotype data were analyzed by selecting the optimal training model to realize the detection of rice appearance quality.Results and discussionThe experimental results showed that the resolution of the system could reach 92.3%. In the detection process, the system designed with this method not only reduces the subjectivity problems caused by different detection environments, visual fatigue caused large sample size and the inspector’s personal factors, but also significantly improves the detection time and accuracy, which further enhances the detection efficiency of rice appearance quality, and has positive significance for the development of the rice industry

    High power rechargeable magnesium/iodine battery chemistry

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    © The Author(s) 2017. Rechargeable magnesium batteries have attracted considerable attention because of their potential high energy density and low cost. However, their development has been severely hindered because of the lack of appropriate cathode materials. Here we report a rechargeable magnesium/iodine battery, in which the soluble iodine reacts with Mg2+ to form a soluble intermediate and then an insoluble final product magnesium iodide. The liquid-solid two-phase reaction pathway circumvents solid-state Mg2+ diffusion and ensures a large interfacial reaction area, leading to fast reaction kinetics and high reaction reversibility. As a result, the rechargeable magnesium/iodine battery shows a better rate capability (180 mAh g-1 at 0.5 C and 140 mAh g-1 at 1 C) and a higher energy density (∼400 Wh kg-1) than all other reported rechargeable magnesium batteries using intercalation cathodes. This study demonstrates that the liquid-solid two-phase reaction mechanism is promising in addressing the kinetic limitation of rechargeable magnesium batteries
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