bluuebunny/crossref_metadata_2025 huggingface dataset:
Infrared-Visual Image Fusion and CNN Model in Electrical Faults Diagnosis
Authors: Su Lei , Ni Qi , Jin Qiao , Cao Boyuan , Xu Zhaohong , Yu Xiao , Wang Dai
Published: May 2021

In this paper, we proposed a new faults diagnosis method based on the fusion of visible and infrared images of electrical equipment. Firstly, the discrete wavelet transform method is used to fuse the visible and infrared images, which enables the accurate location of the electrical equipment. Then, a deep convolution neural network (CNN) model is employed to identify faults in electrical equipment. Three parameters of CNN including connection weight, convolution layer parameters and pooling layer strategy are designed in this paper. The inputs of CNN are the fused reconstructed images and the outputs are the classifications of faults. Finally, simulation experiments and analysis show that the algorithm proposed in this paper can effectively improve the contrast and clarity of the fused images. It can reduce noise interference, and improve the location accuracy of electrical equipment. More specifically, the faults diagnosis rate is improved by 2-6% with the proposed method.
Application of lightweight magnesium alloy in satellite antenna products
Authors: yu-hua Li , Xue Liu Bo , Xiao Bo Zhang , Feng Zhao , Li-Li Jing
Published: May 2021

Combined with the actual work, the new metal matrix composite has the characteristics of light weight, low thermal expansion (CTE), ultra-high thermal conductivity, high specific strength, specific stiffness, good damping, etc. which is the key to realize the requirements of miniaturization, lightweight, long life and high reliability of aerospace products. This paper introduces the selection analysis and practical application of magnesium alloy in satellite antenna products. Antenna products based on magnesium alloy will be more and more widely used in aerospace field.
The design of the position detection system for drilling and stealing oil in oil pipeline
Authors: Qu Weidong , Yu Lijie
Published: May 2021

Oil theft by drilling refers to the theft of oil by drilling and installing branch pipes and valves on the oil pipeline, which can easily cause leakage and lead to the risk of pipeline failure. Drilling and oil theft is a problem that has troubled the oil pipeline enterprises for a long time, and it causes a series of serious consequences every year in China. This paper presents a design method of detecting system for locating the location of drilling and oil theft, which is accurate and reliable in performance. It can be operated under harsh conditions, and is very suitable for high pressure and harsh application environment. It has a good application prospect.
Research on Unmanned End-effector and Its Buffer Parameters
Authors: Zeng Zhe , Shi WenBo , Hou YangYang , Hong HuaJie
Published: May 2021

Based on the future application of integrated reconnaissance and strike of small unmanned combat platform, the parameters of terminal strike weapon and terminal buffer mechanism are designed and analyzed in this paper. Firstly, the internal ballistic simulation of the terminal strike load is carried out and verified with the experimental results. Then, the buffering system is modeled, the buffering parameters are analyzed theoretically and the local optimal solution is analyzed, the general law of the local optimal solution is obtained, and the optimal solution is obtained. Finally, the simulation is carried out.
Structure design of an omni-directional wheeled handling robot
Authors: Wu Binghui , Qin Dezhao , Chen Yuhan , Cao TianQi , Wu Maoliang
Published: May 2021

In response to the demand for automated item handling, this paper proposes an omnidirectional wheeled handling robot. Firstly, determine that its mobile platform is based on the design of the Mecanum wheel, which can move safely and efficiently. Secondly, according to the common object shapes, a single-side opening and closing insertion rack clamping mechanism is proposed. Thirdly, in order to meet the needs of transporting objects and avoid interference with the movement of the moving body, the mechanical arm is a four-degree-of-freedom joint structure. Finally, a decelerated AC servo motor with self-locking function is selected as the drive motor, and a low-speed motor with a reducer is used as the drive element of the moving body.
Electromagnetic Shielding Design of Transfer Orifice for Military Shelter
Authors: Zhang Weiliang , Wan Junlin , Zhang Qi , Gao Dinghan
Published: May 2021

Modern warfare has put forward higher and higher electromagnetic shielding requirements for the shelters loaded with various types of high-performance electronic equipment. The use of high-performance electromagnetic shielding shelters has become an important means to ensure the combat effectiveness and survivability of weapons and equipment. In view of the design of the transfer aperture of a certain type of military shielded shelter, starting from the electromagnetic shielding principle of the shelter, according to the theoretical calculation method of electromagnetic shielding effectiveness, the structural design elements of the shielded shelter transit orifice are detailed. Finally, according to the national military standard for shielding test verification, the shelter transfer orifice can meet the requirements of the shielding index, which can provide reference for the similar shielded shelter design.
Smart Design on the Flexible Gear based on Knowledge Graph
Authors: Hao Qin , Hu Shilin
Published: May 2021

The design of a mechanical component, such as flexible gear, would require plenty of time and energy retrieval relevant design data, information, and knowledge to complete the design tasks. However, current design support tools can hardly assist this requirement. To fill this gap, this paper has proposed a smart design tool based on knowledge graph to intelligent recommend the possible design data, information, and knowledge to engineering designs to facilitate their design tasks and improve design efficiency. This smart design method includes three parts, creating knowledge representation model, constructing knowledge graph, and developing collaborative knowledge management system for implementation. The methodology is demonstrated in this paper with a case study on the design of a double-arc tooth profile flexible gear for a harmonic drive reducer. The results have shown the feasibility of the method, the improvement in the design efficiency through intelligent recommendation of design data, information, and knowledge.
Design of digital recognition system based on FPGA
Authors: Yu Yuting , Qiao Ya , Ren Gangqiang , Jiao Jiajun
Published: May 2021

Digital recognition has become an important application of image recognition. We design a system, which takes FPGA as the core of hardware, Quartus II as the platform of software development, and uses hardware description language to complete the development. It completes the function of digital recognition. After the image is collected by the camera, the printed numbers in the image are recognized and displayed. Experiments demonstrate our design can achieve above functions on portable devices.
Analysis of Scanning Acoustic Microscopy Problems for Plastic Encapsulated Microcircuits with Complex Structure
Authors: Zhao Hailong , Zhang Kui , Zhou Zhenhua , Xi Shanbin , Ran Honglei , Huang Jie , Peng Hao
Published: May 2021

In order to keep up with the development trend of plastic encapsulated technology and effectively improve the Scanning Acoustic Microscopy (SAM) capability of Plastic Encapsulated Microcircuits (PEMs) with complex structure, the structural characteristics of complex packaging devices, the limitations of ultrasonic technology and the applicability of testing standards are systematically studied. The influence of complex package structure and chip coated structure on SAM detection is analysed. The influence of the limitation of ultrasonic technology on the thickness and number of layers of PEMs is studied. Finally, the applicability of SAM test standards is discussed. Through the research, many problems in the SAM detection of PEMs with complex structures are pointed out, and some test requirements and suggestions on test standards are given.
Design of Control System of Alkylation Unit in Petrochemical Enterprise
Authors: Guo Zhicheng , Cai Zhuoen
Published: May 2021

The temperature and liquid level in the alkylation unit are important factors affecting the product qualification rate, and the control is difficult due to the nonlinearity and hysteresis of the system. A control system with single-chip microcomputer MC9S12XS128 as the core is designed to collect operating data such as temperature and liquid level, and use fuzzy control methods to control it within the required range. The hardware circuit and software structure of the system are designed and tested and verified. The results show that the system has a good control effect and meets the requirements of the device for control accuracy and stability.
Simulation of Hydraulic Suspension System of Electric Tractor Based on Matlab-AMESim
Authors: Zhang Wei , Liu Mengnan , Xu Liyou , Zhao Xueping , Fu Xiao
Published: May 2021

For electric tractor engine power output characteristic, a load sensitive hydraulic suspension system in front of the valve is designed. In order to meet the operation requirements of different soil conditions when the electric tractor is plowing, and to improve the dynamic response characteristics of the system and the uniformity of tillage depth, a fuzzy PID based resistance-position combined adjustment tillage depth control strategy is designed. The hydraulic system simulation model is established based on AMESim, and the fuzzy PID controller model is established using Matlab. Through the joint simulation of AMESim and Matlab, the control performance of hydraulic suspension system of electric tractor with different resistance-position comprehensive proportional coefficients is analyzed. The simulation results show that the control strategy of tillage depth based on fuzzy PID is more responsive and anti-interference strong ability, the resistance-position combined adjustment has higher adaptability to different soil changes and operation methods than a single resistance adjustment or position adjustment.
Research and design of resource allocation algorithm in wireless communication system
Authors: Wei Jiaqi , Tian Haoyu
Published: May 2021

Although communication has been a topic of research since the 1960s, the last decade or so has seen a boom in research in this area. This is mainly due to the influence of several comprehensive factors, such as spectrum, power. We research the method Integer Fractional Frequency (IFR) and Fractional Frequency Reuse (FFR). We research some equations in a wireless system. And we calculate the capacity under different channel numbers. We also research the optimal power in a cell system, and the best suitable user number in the system. In a real environment, such a method can optimize the system capacity or performance and we can use a suitable model.
Music genre influence and artist similarity based on data analysis
Authors: Xiao Yuhui , He Zhilin , Liao Huming , Huang Kangjian , Zhao Jianping , Wu Yuchen
Published: May 2021

Based on related data and cluster analysis, this paper creates a mathematical model of similarity measurement based on the data set, and finally obtains the influence of different music genres on their followers and the similarity of artists of different musical genres. Here, since the study is about the similarity of music, it is divided into 2 categories according to the provided music characteristics and related indicators of music type. The data is standardized and normalized. Because there is no clear indicator to measure the similarity of music, we use spss to perform K-means clustering analysis. Here, since the similarity of music is studied, it is built on the music characteristics and music provided. Types of related indicators divide it into two categories for analysis. In order to determine the reliability of the model, this article uses meaningful learning to train 70% of the previous data, 30% to test, and finally establishes a complete mathematical model.
Distribution network planning and inventory management in a multi-retailing supply chain
Authors: Ji Jindi , Wang Yuxin , Jia Haitao , Shi Mingjun
Published: May 2021

A In this paper, we are aimed at discussing problems of distribution network planning and inventory management in a multiple-retailing supply chain. We study the distribution model and inventory management model, integrating both models to analyse the optimal decisions on maximum profit. The main methodology we used is literature study and model formulations. Through the research, we finally present the optimal distribution and inventory decision.
Analytical Solutions in a First-order Cubic Nonlinear System with Periodically Forced Oscillator
Authors: Sun Danping , Chen Lanzheng , Wan Renzhuo , Zhou Guopeng
Published: May 2021

In this paper, the analytical solutions for the period-1 motion of a cubic nonlinear dynamical system with two periodic forced terms are obtained through the generalized harmonic balance method. From the method, the analytical solutions are transformed to the Fourier series expansion in all harmonic terms at the equilibrium position. The stability and bifurcation analysis are investigated through eigenvalues analysis, and the accuracy of the analytical solutions is verified by numerical simulations. The harmonic amplitude distributions are presented to show the characteristic of the different-order terms with different excitation frequencies. From this study, the system parameters that make the system stable are determined. Furthermore, the robustness of the system is guaranteed by selecting the parameters appropriately.
Application of 3D Modeling in Real Estate and Land Integration Project
Authors: Han Qi , Yuan Xitun , Yang Xiongfei , Zhang Hang , Wen Yongxiao
Published: May 2021

With the development of science and technology, surveying and mapping technology has also advanced by leaps and bounds. More and more people in related industries have begun to pay more attention to the application of drone tilt photogrammetry to the surveying and mapping industry, which has greatly improved the progress of surveying and mapping projects. This photography technology has gradually become an indispensable part of the surveying and mapping industry due to its advantages of speed, efficiency, flexibility, and low cost. This article is aimed at the integration of premises and land project, using a drone platform equipped with 5 lens cameras and shooting from 5 directions at the same time, that is, through 1 vertical shooting lens and 4 tilting lenses to obtain ground surface images, to achieve a large overlap of multiple angles For viewing angle, the requirement for overlap is that the heading overlap is at least 60%, and the side overlap is 30%. This article uses ContextCapture Center Master software to perform three-dimensional modeling of the acquired images and obtain orthophoto results. The three-dimensional model is loaded into the EPS software for collection. The buildings, eaves, balconies and other buildings in each parcel of land are collected, and they are finally obtained. This technology greatly improves the work efficiency of the real estate integration project.
The Application of the Paradigm of Soft Set Logic Formula in Recommendation System
Authors: Lu Xiao , Liu Jingwen
Published: May 2021

With the development of science and technology, information has shown explosive growth. It is difficult for information consumers to find useful information from a large amount of information. This article combines soft set theory and propositional calculus to propose a recommendation algorithm that meets the requirements of users. The algorithm describes user requirements in terms of soft set logic formulas and gives reasonable recommendation results by solving the normal form of the sub-formula and its realization in the corresponding soft subset. Numerical example shows that the algorithm can be successfully applied to the problem of song recommendation.
A smarter algorithm-IFR3+FFR in wireless network to optimize frequency allocation
Authors: Fu Zanwen , Zhou Rui
Published: May 2021

All latest technologies require frequency channels to be allocated intelligently so that interference can be avoided. Nowadays, it is still quite challenging for people to propose an effective method to enhance the frequency allocation system, which reduces interference further and allows more users to utilize the base station at the same time. Here we describe the method of improving the frequency allocation system-IFR3 (Integer frequency reuse) plus FFR (fractional frequency reuse) in a nineteen-cell network. We simulate the system based on MATLAB, comparing capacity results against different parameters. We draw some useful conclusions after the simulation. When the number of frequencies increases, average network capacity also increases. When SNR increases, average network capacity increases at the beginning, and then at a certain critical point, it starts to decrease. Thereby, it is required to find the best system with both the appropriate number of frequencies and SNR to maximize the network capacity. As for users who are in the distance, the interference will be large when using IFR1 but small if using IFR3. Therefore, finding the best reuse factor when using FFR is indispensable. Smaller transmit power should be allocated to users in the cell’s inner area, and larger transmit power allocated to users in the outer area of the cell. This system is more advanced and capable of reducing interference efficiently.
The investigation of travelling wave solutions to some coupled space-time fractional differential equations in fluids
Authors: Zhao Meimei
Published: May 2021

Solutions of nonlinear coupled fractional differential equations (FDEs), namely, the space-time fractional coupled Burgers’ equations, coupled MKdV equations, and coupled KdV equations are obtained by the improved fractional sub-equation method in the sense of Jumarie’s modified Riemann-Liouville derivative. The form of these solutions suggests ansatz suitable for finding solutions of much more general FDEs of coupled type.
Optimization of Marine Debris Collection Routing for Solar and Diesel Hybrid Power Vessels
Authors: Tao Ling , Duan Gang , Wei Yuejiao , Chen Xiaohui , Fan Tao
Published: May 2021

With the increase of marine debris and the serious destruction of the ecological environment, marine debris collection has become an urgent task facing us. In this paper, the logistics network is used to optimize the routing of marine debris collection vessels. In order to reduce carbon emissions, we choose to use new energy waste collection vessels which have solar and diesel hybrid power. The objection of this paper is to minimize the total cost. The constraints include time window, vessel capacity and carbon emissions, which are solved by large-scale neighborhood search algorithm. Taking the East China Sea as an example, the results show that the total cost and total time can be saved by 20.58% and 17.43% respectively by choosing the best debris collection time. Under different environmental conditions, when the photovoltaic penetration of solar hybrid vessel reaches 75%, the cost can be saved by 22.14%, and the carbon emission can be reduced by 74.7%. Through the analysis of different types of vessels, it is found that 11.85% of the cost can be saved by selecting the best vessel type.
Short-term Demand Forecasting of Shared Bicycles Based on Seasonal Grey Markov Model
Authors: Liu Hengzi , He Yulong , Song Tailong , Xu Peng
Published: May 2021

According to the characteristics of periodicity, nonlinearity and randomness of shared bicycle riding data, a seasonal grey Markov model was proposed. In the new prediction model, the seasonal GM (1,1) model was used to get the prediction results firstly. Then, Markov model was used to modify the prediction residual. In the process of residual correction, the residual sequence was selected according to the new information priority principle, and the residual was modified by the expectation of the median value in the state interval, which improves the prediction accuracy of the model. Finally, the model was applied to the demand forecast of the Citi Bike shared bicycles in New York, the first three weeks of June 2019 during the Saturday peak hours. The numerical results show that the mean absolute percentage error (MAPE) of predicted value of seasonal grey Markov model is 2.72%, which is superior to the traditional GM (1,1) model, seasonal GM (1,1) model and grey Markov model.
The Radon Transformation and Its Application in Tomography
Authors: Fang Kaile
Published: May 2021

In a mathematical setting, the radon transformation is in the form of integration, which was proposed by Johann Radon in 1917. Radon transform has been applied in multiple fields of study, especially in medical research. The Radon transform can represent the data obtained from tomographic scans, so the inverse of Radon transform can be used to reconstruct the original projection properties, which is useful in computed axial tomography, electron microscopy, reflection seismology, and in the solution of hyperbolic partial differential equations. This paper summarizes the indispensable role of the radon transformation and gives a simple proof of the back-projection formula.
A two-dimensional SiGeO monolayer with high electron mobility and negative Poisson’s ratio
Authors: Lan Zhi-Shui , Liu Chun-Sheng , Yan Xiao-Hong
Published: May 2021

In this paper, we perform the first-principle calculations to explore the electronic and mechanical properties of two-dimensional SiGeO. SiGeO is an indirect band gap semiconductor with a gap of 1.29 eV and a high electron mobility of 1.70×103 cm 2V−1 s−1. The uniaxial strain can trigger the indirect-to-direct band gap transition. Moreover, SiGeO exhibits an extraordinary auxetic property, and its in-plane negative Poisson’s ratio is three times larger than that of borophenes. These properties would endow two-dimensional SiGeO with great potential in the application of electromechanical devices.
Study on flame retardant properties of Plywood Made with Eucalyptus, Birch and Poplar Wood
Authors: Pingli Li , Xiang Zhang , Chaolu Yin , Fuxin Fu
Published: May 2021

In this work, the laboratory-made flame-retardant polyvinyl alcohol adhesive was used to prepare flame-retardant plywood made with eucalyptus, birch and poplar respectively, and the effect of tree species on the Thermogravimetric behavior and flame-retardant properties of flame-retardant plywood was studied. Thermogravimetric behavior of the flame-retardant plywood prepared by eucalyptus, birch and poplar showed that poplar plywood had highest thermostability.The results of the SBI test are consistent with the results of the LOI test and Thermogravimetric analysis, both indicated that the tree species had a significant effect on the flame-retardant properties of the flame-retardant plywood, the flame-retardant plywood made with poplar veneer has the highest LOI value, lowest HRR value and lowest THR value.
Analysis of the impact of various charging modes on grid connection of electric vehicles
Authors: Zhang Zeheng , Li Weihua , Ran Youhong , Liu Dianxiang
Published: May 2021

In recent years, as a new type of green energy, electric vehicles have developed rapidly. However, the charging behavior of electric vehicles is uncertain in time and season. A large number of electric vehicles connect the load with the power grid through different charging methods, which leads to the load redistribution of the power grid. Therefore, the research on the impact of load on distribution network under different conditions can give full play to the role of electric vehicles in peak load regulation and valley filling of power grid, which is of great significance to adjust charging behavior and improve power supply reliability of power grid.

Firstly, according to the factors that affect the charging load of electric vehicles, the charger models under different charging modes and IEEE-14 node distribution network models are established. In addition, considering the daily living habits of the citizens, this paper proposes two normal distribution models to study the load distribution law of electric vehicles connected with the distribution network in different periods, and draw a one-day load curve. The peak load caused by people’s charging behavior in one day is explained and analyzed. Finally, the effects of different seasons on charging behavior and charging efficiency are simulated, and the load curves of different seasons are drawn, and the results are analyzed comprehensively.
Design of voice temperature control faucet based on STM32 MCU
Authors: Ruijie Yang , Yan Wang , Fan Yi , Xudong Han
Published: May 2021

Everyone has a different perception of water temperature. Considering the living needs of people today, a faucet that can adjust the water temperature intelligently has a good research value. Different from traditional products, the voice temperature control faucet designed in this paper can not only automatically regulate the temperature, but also keep a constant temperature. When the hot water supply is insufficient, it can give an alarm in advance to remind the customer to complete the water use as soon as possible. This design uses the existing speech signal module, it can convert the speech signal into the single chip microcomputer input signal, and then through the single chip microcomputer control of the motor rotation, so as to control the opening of cold and hot water very well. Through the effective combination of temperature sensing technology, speech recognition algorithm and MCU, the goal of intelligent temperature control can be achieved.
One-pot synthesis of gold nanocubes
Authors: Wen Xin , Zhang Lei , Tian Jiangwei
Published: May 2021

Precious metal nanomaterials have the advantages of low toxicity, optical stability, water-solubility, good biocompatibility and strong photoluminescence. In this paper, by controlling the proportion of the reaction substance, the amount of reducing agent, pH value, reaction temperature and reaction time, we synthesized the fluorescent gold nanocubes with uniform size and morphology, good fluorescence signal and excellent biocompatibility. It provides some guidance for the shape control of nanocubes synthesis.
Research on Static Rolling Angular Stiffness of Linear Motion Ball Guide
Authors: Wang Tianyu , Jiang Shuyun
Published: May 2021

The purpose of this study is to investigate the static rolling angular stiffness characteristics of the linear motion ball guide (LMBG). Firstly, a deformation compatible equation of the LMBG under rolling moment is derived by deformation compatible hypothesis, and then the model of static stiffness for the LMBG is developed using the Hertz contact theory, the deformation compatible equation and force equilibrium equation Finally, the static rolling stiffness of the LMBG was analyzed systematically via a case study, and the simulated results were verified by the experimental data
Research on the Pre-sintering Temperature During the Preparation of (1-x) NBT–xBaTiO3 Serial Ceramics
Authors: Yu Jinghua , Feng Qianwen
Published: May 2021

According to the formula of (1-x)NBT-xBaTiO3, this study selects different composition points and measures the volume density and piezoelectric property of the samples at different pre-sintering temperatures, ultimately determining the optimal pre-sintering temperature. Experiments show that for ceramic based on (1-x)NBT-xBaTiO3, when x<0.06 the optimal pre-sintering temperature should be 900°C; when x≥0.06, it should be 950°C.
Research on Unmanned Static Trajectory
Authors: Xie Peng Yang , Chen Ling Xuan , Hua Ma Shuai , Miao Tong Sheng
Published: May 2021

With the development of science and technology, the intelligence of society is getting higher and higher. The development of safe and reliable intelligent driving has become one of the important topics in today’s era. As a high-tech complex integrating environmental awareness, planning decision-making, control execution and information interaction, driverless cars are increasingly becoming the needs of the times.[1] How to accurately extract effective information to provide safe and reliable control instructions for the next decision-making of vehicles in complex multi-source and heterogeneous environment is the technical basis of intelligent driving.

In this paper, a certain amount of research has been done on lane change trajectory planning in different environments. In the aspect of static driving environment, a lane-changing trajectory planning method based on the fifth-order Bessel curve is planned. The physical problems are transformed into optimization problems of coordinate points of Bessel curve expression by planning the left and right boundaries of feasible region through lane-changing trajectory. [2]In the aspect of dynamic driving, based on the model predictive control theory, a lane-changing trajectory optimization method for multi-lane and multi-surrounding vehicles is proposed.
Recent progress in drug delivery and cancer theranostic built from metal-organic framework
Authors: Yang Peng , Chen Zhuang , Liu Shaojie , Qiao Chaoqiang , Xia Yuqiong , Wang Zhongliang
Published: May 2021

With the improvement of living standards, cancer has become a great challenge around the world during last decades, meanwhile, abundant nanomaterials have been developed as drug delivery system (DDS) or cancer theranostic agents (CTAs) with their outstanding properties. However, low multifunctional efficiency and time-consuming synthesis limit their further applications. Nowadays, green chemistry, in particular, the concept of atom economy, has defined new criteria for the simplicity and efficient production of biomaterials for nanomedicine, which not only owns the property of spatio-temporal precision imaging, but also possess the ability to treat cancer. Interestingly, metal-organic framework (MOF) is an excellent example to meet the requirements behind this concept and has great potential for next-generation nanomedicine. In this review, we summarize our recent researches and inspiring progresses in designing DDS and CTA built from MOF, aiming to show the simplicity, control, and versatility, and provide views on the development of MOF-based nanomedicine in the future.
Nitrogen dynamics in cropping systems under Mediterranean climate: a systemic analysis
Authors: Lassaletta Luis , Sanz-Cobena Alberto , Aguilera Eduardo , Quemada Miguel , Billen Gilles , Bondeau Alberte , Cayuela Maria Luz , Cramer Wolfgang , Eekhout Joris P C , Garnier Josette , Grizzetti Bruna , Intrigliolo Diego S , Ruiz Ramos Margarita , Romero Estela , Vallejo Antonio , Gimeno Benjamín S
Published: May 2021

Worldwide, Mediterranean cropping systems face the complex challenge of producing enough high-quality food while preserving the quantity and quality of scarce water for people and agriculture in the context of climate change. While good management of nitrogen (N) is paramount to achieving this objective, the efficient strategies developed for temperate systems are often not adapted to the specificities of Mediterranean systems. In this work, we combine original data with a thorough literature review to highlight the most relevant drivers of N dynamics in these semi-arid systems. To do so, we provide an analysis at nested scales combining a bottom-up approach from the field scale, with a top-down approach considering the agro-food system where cropping systems are inserted. We analyze the structural changes in the agro-food systems affecting total N entering the territory, the contrasting response of yields to N availability under rainfed and irrigated conditions in a precipitation gradient, the interaction between N management and climate change adaptation, the main drivers affecting the release of Nr compounds (nitrate, ammonia, nitric oxide and nitrous oxide) compared with temperate systems and finally, the behavior of N once exported to highly regulated river networks. We conclude that sustainable N management in Mediterranean cropping systems requires the specific adaptation of practices to particular local agro-environmental characteristics with special emphasis on water availability for rainfed and irrigated systems. This approach should also include a systemic analysis of N input into the territory that is driven by the configuration of the agro-food system.
The impact of air pollution alert services on respiratory diseases: generalized additive modeling study in South Korea
Authors: Hahm Yeankyoung , Yoon Heeyeun
Published: May 2021

To reduce human exposure to particulate matter (PM), governments have enacted various preventive measures, to which a warning system is central. To the best of our knowledge, we are the first to assess the effectiveness of mobile-based warning systems on respiratory health outcomes, examining two types of

P

M

2.5

(particles less than

2.5
μ

m

in diameter) alerts via text messaging systems: Wireless Emergency Alert (WEA) and Air Quality Information Text (AIT) as employed in South Korea from January 2015 to October 2019. We used a generalized additive model to control the non-linear relationship between the

P

M

2.5

level and the number of hospital visits and admissions for four respiratory sicknesses—chronic obstructive pulmonary disease, respiratory tract infection, asthma, and pneumonia—while deciphering how such visits and admissions are reduced by the warning systems. Our results found that both systems reduced the number of new patients with the four sicknesses at a 5% statistical significance level. Of the two, WEA was found to be more effective than AIT. The former reduced the number of new patients by 16.4%, while the latter did so by 2.8%. WEA is for everyone with a cell phone connection. By sending simple and direct alerts to a broader range of people, WEA would help people to reduce the chance of short-term exposure to PM in general. The findings provide evidence with policy implications regarding air pollution adaptation.
Deformed hopfion-Rañada knots in ModMax electrodynamics
Authors: Dassy Clémentine , Govaerts Jan
Published: May 2021

Source-free so-called ModMax theories of nonLinear electrodynamics (NLE) in the four dimensional Minkowski spacetime vacuum are the only possible continuous deformations—and as a function of a single real and positive parameter—of source-free Maxwell linear electrodynamics (MLE) in the same vacuum, which preserve all the same Poincaré and conformal spacetime symmetries as well as the continuous duality invariance of Maxwell’s theory. Null field configurations of the latter however, including null electromagnetic knots, are singular for the Lagrangian formulation of any spacetime Poincaré and conformal invariant theory of NLE. In particular null hopfion-Rañada (HR) knots are a distinguished and fascinating class on their own of topologically nontrivial solutions to Maxwell’s equations. This work addresses the fate of these configurations within ModMax theories. A doubled class of ModMax deformed HR knots is thereby identified, each of which coalescing back in a continuous fashion to the original HR knot when the nonlinear deformation parameter is turned off.
Spatial Groundwater Modelling of Micro Watersheds – A case study at Junewani watershed, Hingna Taluk, Nagpur, Maharashtra
Authors: Biroju Priyesh , Katpatal Y B
Published: May 2021

A model is a simplified representation of the complex natural world. The groundwater model provides a quantitative framework for synthesizing field information and for conceptualizing hydrogeological purposes. The present study aims to utilize remotely sensed data, Geographical Information System (GIS), and limited flow modeling to identify the groundwater recharge management practices carried out in the Junewani watershed of the Nagpur district. In this study, Modflow-NWT, in conjunction with spatial analyses, is used for modeling Groundwater flow in Junewani Watershed located at 78.90°E and 21.03°N in Nagpur District, Maharashtra. Since minimal data on flow parameters are available and aquifer systems are also heterogeneous, water level data observed from dug wells has also been used to generate the groundwater flow directions. The study area consists of 1st, 2nd and 3rd order streams and is covered with Black cotton soil and Vesicular Basalt underneath. Watershed boundary conditions, elevation details, drainage patterns, layer properties, permeability values, average rainfall, etc. are given as input for the model. The initial input data has been procured from GSDA Nagpur and through field observations. This study discusses the micro watershed groundwater modeling carried out mainly in a spatial environment supported by results of limited flow modelling, but the results and insights from this study will help in better understanding the GW flow regime after the recharge decisions were taken and the recharge practices were operated. It has been observed that recharge practices in surface dams and desilting have been beneficial at some places, while groundwater has decreased at other places. Thus it helps in decision making regarding the development of GW recharge and utilization.
Bound states and energy eigenvalues of a radial screened Coulomb potential
Authors: Stachura E , Hancock N
Published: May 2021

We analyze bound states and other properties of solutions of a radial Schrödinger equation with a new screened Coulomb potential. In particular, we employ hypervirial relations to obtain eigen-energies for a Hydrogen atom with this potential. Additionally, we appeal to a sharp estimate for a modified Bessel function to estimate the ground state energy of such a system. Finally, when the angular quantum number ℓ ≠ 0, we obtain evidence for a critical screening parameter, above which bound states cease to exist.
Multi-scale tensor network architecture for machine learning
Authors: Reyes J A , Stoudenmire E M
Published: May 2021

We present an algorithm for supervised learning using tensor networks, employing a step of data pre-processing by coarse-graining through a sequence of wavelet transformations. These transformations are represented as a set of tensor network layers identical to those in a multi-scale entanglement renormalization ansatz tensor network. We perform supervised learning and regression tasks through a model based on a matrix product states (MPSs) acting on the coarse-grained data. Because the entire model consists of tensor contractions (apart from the initial non-linear feature map), we can adaptively fine-grain the optimized MPS model ‘backwards’ through the layers with essentially no loss in performance. The MPS itself is trained using an adaptive algorithm based on the density matrix renormalization group algorithm. We test our methods by performing a classification task on audio data and a regression task on temperature time-series data, studying the dependence of training accuracy on the number of coarse-graining layers and showing how fine-graining through the network may be used to initialize models which access finer-scale features.
Machine learning modeling of materials with a group-subgroup structure
Authors: Kayastha Prakriti , Ramakrishnan Raghunathan
Published: May 2021

Crystal structures connected by continuous phase transitions are linked through mathematical relations between crystallographic groups and their subgroups. In the present study, we introduce group-subgroup machine learning (GS-ML) and show that including materials with small unit cells in the training set decreases out-of-sample prediction errors for materials with large unit cells. GS-ML incurs the least training cost to reach 2%–3% target accuracy compared to other ML approaches. Since available materials datasets are heterogeneous providing insufficient examples for realizing the group-subgroup structure, we present the ‘FriezeRMQ1D’ dataset with 8393 Q1D organometallic materials uniformly distributed across seven frieze groups. Furthermore, by comparing the performances of FCHL and 1-hot representations, we show GS-ML to capture subgroup information efficiently when the descriptor encodes structural information. The proposed approach is generic and extendable to symmetry abstractions such as spin-, valency-, or charge order.
Repurposed drug against COVID-19: nanomedicine as an approach for finding new hope in old medicines
Authors: Ahmad Mohammad Zaki , Ahmad Javed , Aslam Mohammed , Khan Mohammad Ahmed , Alasmary Mohammed Yahia , Abdel-Wahab Basel A
Published: May 2021

The coronavirus disease 2019 (COVID-19) has become a threat to global public health. It is caused by the novel severe acute respiratory syndrome coronavirus (SARS-CoV-2) and has triggered over 17 lakh causalities worldwide. Regrettably, no drug or vaccine has been validated for the treatment of COVID-19 and standard treatment for COVID-19 is currently unavailable. Most of the therapeutics moieties which were originally intended for the other disease are now being evaluated for the potential to be effective against COVID-19 (re-purpose). Nanomedicine has emerged as one of the most promising technologies in the field of drug delivery with the potential to deal with various diseases efficiently. It has addressed the limitations of traditional repurposed antiviral drugs including solubility and toxicity. It has also imparted enhanced potency and selectivity to antivirals towards viral cells. This review emphasizes the scope of repositioning of traditional therapeutic approaches, in addition to the fruitfulness of nanomedicine against COVID-19.
Almost everywhere regularity for the free boundary of the 𝑝-harmonic obstacle problem 𝑝>2
Authors: Andersson J.
Published: May 2021

Let

u
u

be a solution to the normalized

p
p

-harmonic obstacle problem with

p
>
2

p>2

. That is,

u
∈

W

1
,
p

(

B
1

(
0
)
)

u\in W^{1,p}(B_1(0))

,

2
>
p
>
∞

2>p>\infty

,

u
≥
0

u\ge 0

and
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="normal d normal i normal v left-parenthesis StartAbsoluteValue nabla u EndAbsoluteValue Superscript p minus 2 Baseline nabla u right-parenthesis equals chi Subscript left-brace u greater-than 0 right-brace Baseline in upper B 1 left-parenthesis 0 right-parenthesis">

d
i
v

(

|

∇
u

|

p
−
2

∇
u
)
=

χ

{
u
>
0
}

 
 in 
 

B
1

(
0
)

\begin{equation*} \mathrm {div}( |\nabla u|^{p-2}\nabla u)=\chi _{\{u>0\}} \ \text { in } \ B_1(0) \end{equation*}

where

u
(
x
)
≥
0

u(x)\ge 0

and

χ
A

\chi _A

is the characteristic function of the set

A
A

. The main result is that for almost every free boundary point with respect to the

(
n
−
1
)

(n-1)

-Hausdorff measure, there is a neighborhood where the free boundary is a

C

1
,
β

C^{1,\beta }

-graph. That is, for

H

n
−
1

\mathcal {H}^{n-1}

-a.e. point

x
0

∈
∂
{
u
>
0
}
∩

B
1

(
0
)

x^0\in \partial \{u>0\}\cap B_1(0)

there is an

r
>
0

r>0

such that

B
r

(

x
0

)
∩
∂
{
u
>
0
}
∈

C

1
,
β

B_r(x^0)\cap \partial \{u>0\}\in C^{1,\beta }

.
The leading edge of a free boundary interacting with a line of fast diffusion
Authors: Caffarelli L. , Roquejoffre J.-M.
Published: May 2021

Our goal in this work is to explain an unexpected feature of the expanding level sets of the solutions of a system where a half-plane in which reaction-diffusion phenomena occur exchanges mass with a line having a large diffusion of its own. The system was proposed by H. Berestycki, L. Rossi, and the second author as a model of enhancement of biological invasions by a line of fast diffusion. It was observed numerically by A.-C. Coulon that the leading edge of the front, rather than being located on the line, was in the lower half-plane.

We explain this behavior for a closely related free boundary problem. We construct travelling waves for this problem, and the analysis of their free boundary near the line confirms the predictions of the numerical simulations.
On a class of sharp multiplicative Hardy inequalities
Authors: Guzu D. , Hoffmann-Ostenhof T. , Laptev A.
Published: May 2021

A class of weighted Hardy inequalities is treated. The sharp constants depend on the lowest eigenvalues of auxiliary Schrödinger operators on a sphere. In particular, for some block radial weights these sharp constants are given in terms of the lowest eigenvalue of a Legendre type equation.
𝐿_{𝑝}-estimates of solution of the free boundary problem for viscous compressible and incompressible fluids in the linear approximation
Authors: Solonnikov V.
Published: May 2021

The paper contains

L
p

L_p

-estimates and a theorem on the local in time solvability of the problem arising as a result of linearization of the free boundary problem for two viscous fluids, compressible and incompressible, contained in a bounded vessel, separated by a free interface, and subject to mass and capillary forces. This result is known for the case of

p
=
2

p=2

; it serves as an analytical basis for the study of the complete nonlinear problem. The proof is based on the “maximal regularity” estimate of the solution obtained with the help of the

L
p

L_p

Fourier multiplier theorem due to P. I. Lizorkin.
Magnitude, change over time, demographic characteristics and geographic distribution of excess deaths among nursing home residents during the first wave of COVID-19 in France: a nationwide cohort study
Authors: Canouï-Poitrine Florence , Rachas Antoine , Thomas Martine , Carcaillon-Bentata Laure , Fontaine Roméo , Gavazzi Gaëtan , Laurent Marie , Robine Jean-Marie
Published: May 2021

Background

The objectives were to assess the excess deaths among Nursing Home (NH) residents during the first wave of the COVID-19 pandemic, to determine their part in the total excess deaths and whether there was a mortality displacement.

Methods

We studied a cohort of 494,753 adults in 6,515 NHs in France exposed to COVID-19 pandemic (from 1 March to 31 May 2020) and compared with the 2014–2019 cohorts using data from the French National Health Data System. The main outcome was death. Excess deaths and standardized mortality ratios (SMRs) were estimated.

Result

There were 13,505 excess deaths. Mortality increased by 43% (SMR: 1.43). The mortality excess was higher among males than females (SMR: 1.51 and 1.38) and decreased with increasing age (SMRs in females: 1.61 in the 60–74 age group, 1.58 for 75–84, 1.41 for 85–94 and 1.31 for 95 or over; males: SMRs: 1.59 for 60–74, 1.69 for 75–84, 1.47 for 85–94 and 1.41 for 95 or over). No mortality displacement effect was observed up until 30 August 2020. By extrapolating to all NH residents nationally (N = 570,003), we estimated that they accounted for 51% of the general population excess deaths (N = 15,114 out of 29,563).

Conclusion

NH residents accounted for half of the total excess deaths in France during the first wave of the COVID-19 pandemic. The excess death rate was higher among males than females and among younger than older residents.