An Investigation of Purely Azimuthal Passive Localization and Position Adjustment in Attempted UAV Formation Flights

When a cluster of unmanned aerial vehicles (UAVs) is flying in formation, it is crucial to maintain the formation and not to be interfered by external electromagnetic wave signals. In order to maintain the formation, this paper proposes to use pure azimuth passive positioning to adjust the position of UAVs, i.e., certain UAVs in the formation transmit signals, the rest of the UAVs receive the signals passively, and extract the orientation information from them to adjust the position of the UAVs [1] [2] [3]. In this paper, the position adjustment problem of UAVs in “circular” formation flight under three models is investigated. To address the problem of “how to obtain the position of the receiving UAV when there are two UAVs with known numbers and evenly distributed on the circumference in addition to the UAV transmitting at the known center of the circle, and the rest of the UAVs with slight deviations in their positions are receiving the signals”, two purely mathematical geometric methods, namely, triangular localization method and polar co-ordinate method, are proposed respectively. We have determined the position of the receiving UAV;we have used the exhaustive method and the construction and disproof method to solve the problem of “how many UAVs are needed to transmit signals in order to realize the effective positioning of the UAVs when it is known that a certain UAV with a slight deviation in its position receives the signals emitted by two UAVs at the same time”, and the results show that: in addition to the known signals emitted by two UAVs, it is also necessary to transmit the signals emitted by two UAVs. The results show that in addition to the known two UAVs transmitting signals, two additional UAVs are required to transmit signals for precise po-sitioning. When the position of UAVs has deviation at the initial moment, the ideal approximation method and the target delimitation method are pro-posed, and the target of nine UAVs uniformly distributed on a circle of a spe-cific radius is achieved through several adjustments, after which the ad-vantages and disadvantages of each model are analyzed, and suggestions for improvement are put forward. The purely azimuthal passive localization method and the constructed model approach proposed in this paper can be extended to other fields, such as spacecraft formations in space and battle-ship formations at sea, as well as other formation flight position adjustment problems.

Eco-friendly corrosion inhibitor from Pennisetum purpureum biomass and synergistic intensifiers for mild steel

Extracts of elephant grass(Pennisetum purpureum) blended with some intensifier halides like ammonium chloride(AMC) and potassium iodide(PTI) were investigated as corrosion inhibitor for mild steel.The corrosion process was monitored in 3.5% HCl by mass loss and electrochemical techniques at 30,40,50,60 and 90 °C.Addition of AMC and PTI increased the inhibition efficiency with the highest inhibition efficiency obtained with PTI blended extract.The blends behaved as mixed type inhibitors and were spontaneously adsorbed on mild steel surface in exothermic nature.Synergistic parameters of the intensifier ions revealed cooperative effect.Kinetic data treatment indicated increase in energy barrier by intensifier ions.The results demonstrate that elephant grass extract blended with halide ions can act as alternative ecofriendly inhibitor for mild steel at elevated temperatures.

极板凹凸排布对微流通道流动性能影响研究

目前电解单元极板多采用球凸球凹的组合布置形式,其目的是为了增强通道内部的抗扰动能力,提高流体分布的均匀性。为更深入改进通道内流场分布,采用CFD数值模拟的方法对比了5种不同球凸球凹排布方式内部的流场分布特性。结果表明,5种组合布置形式在入口处均呈涡旋运动的特点,且case A方形扩列在入口处的涡旋运动范围较小;布置的形式会影响流场的分布,在球凹球凸单元间形成连续的低速尾迹区,形成较大的速度梯度;温度场的分布与流体速度分布大体呈负相关;所有通道均有速度分量uw的负速度区域,其对应湍流动能较大;通道内部的凹凸单元布置形式会影响局部流动细节,改善流场分布均匀性,其中case A方形顺列的内部流场均匀性最佳。

THE RIEMANN PROBLEM FOR ISENTROPIC COMPRESSIBLE EULER EQUATIONS WITH DISCONTINUOUS FLUX

We consider the singular Riemann problem for the rectilinear isentropic compressible Euler equations with discontinuous flux,more specifically,for pressureless flow on the left and polytropic flow on the right separated by a discontinuity x=x(t).We prove that this problem admits global Radon measure solutions for all kinds of initial data.The over-compressing condition on the discontinuity x=x(t)is not enough to ensure the uniqueness of the solution.However,there is a unique piecewise smooth solution if one proposes a slip condition on the right-side of the curve x=x(t)+0,in addition to the full adhesion condition on its left-side.As an application,we study a free piston problem with the piston in a tube surrounded initially by uniform pressureless flow and a polytropic gas.In particular,we obtain the existence of a piecewise smooth solution for the motion of the piston between a vacuum and a polytropic gas.This indicates that the singular Riemann problem looks like a control problem in the sense that one could adjust the condition on the discontinuity of the flux to obtain the desired flow field.

一种植物工厂内可移动装配式大黄育苗装置设计

设计的可移动装配式大黄育苗装置由发光二极管(Lighting Emitting Diode,LED)补光系统、水肥一体化系统、栽培系统和自动控制系统等组成,可以随时拆卸、重组,方便搬运、调整,便于回收和再利用,适应性强,具有集约化和标准化的特点,是大黄工厂化育苗的一种省力型生产装置。

Evaluation of Phytochemical Contents and Antimicrobial Activities of Pandiaka heudelotii

The work investigated the secondary metabolites present in different parts of the Pandiaka heudelotii plant harvested from Ezira, Orumba south local government area of Anambra state, southeastern Nigeria as well as their antimicrobial activity. The objectives were to extract, determine the phytochemicals present, evaluate the antimicrobial potential and determine the zones of inhibition of the root, stem and leaf extracts of the plant. The emergence of antibiotics has decreased the spread and severity of a wide range of diseases. Plant extracts were tested for antibacterial and antifungal activities against Staphylococcus aureus, Escherichia coli, Proteus vulgaris, Streptococcus pyogenes, Bacillus subtelis, Pseudomonas aerogenes, Salmonella typhi, Aspergillus flavus, Aspergillus niger and Candida albicans. The zone of inhibition of extracts was compared with that of standard drugs like Erythromycin, Ciprofloxacin, Fulcin and Fluconazole. The result revealed the inhibition of bacterial and fungal growth with some test organisms. The microbial activity of the plant parts may be due to the presence of various secondary metabolites. The ethyl acetate extracts of Pandiaka heudelotii stood out with a minimum inhibitory concentration (MIC) range of 5 - 10 mg/mL and a minimum bactericidal concentration (MBC)/minimum fungicidal concentration (MFC) of 10 - 20 mg/ml against some test organisms. The plant can thus be worked upon to discover biologically active natural products that may serve as a prelude to the development of new pharmaceutical research undertakings.

Navigation Finsler metrics on a gradient Ricci soliton

In this paper,we study a class of Finsler metrics defined by a vector field on a gradient Ricci soliton.We obtain a necessary and sufficient condition for these Finsler metrics on a compact gradient Ricci soliton to be of isotropic S-curvature by establishing a new integral inequality.Then we determine the Ricci curvature of navigation Finsler metrics of isotropic S-curvature on a gradient Ricci soliton generalizing result only known in the case when such soliton is of Einstein type.As its application,we obtain the Ricci curvature of all navigation Finsler metrics of isotropic S-curvature on Gaussian shrinking soliton.

Modeling Blood Flow in Veins of Uniform Properties (Giraffe Jugular Vein)

This paper models the giraffe’s jugular veins as a uniform collapsible tube from a rigid skull. The equations governing one-dimensional steady flow through such a tube for various conditions have been developed. The effects of inertial and inclination angles that have not been discussed previously have been included. It has been shown that different flows for a uniform tube (vein) are possible. However, this flow matches that of a jugular vein which is supercritical, and the steady solution has been given by the balance between the driving forces of gravity and the viscous resistance to the flow at the right atrium of the heart must be sub-critical for a fixed right-atrium pressure which means that an elastic jump is required to return the flow to sub-critical from the supercritical flow upstream this type of relationship gives rise to flow limitation at the same time given any right atrium fixed pressure there exists a maximum flow rate which when exceeded the boundary conditions of the flow do not hold boundary conditions at the right atrium are not satisfied hence making the steady flow impossible this mechanism of flow limitation is slightly different from the other one in that causes airways through forced expiration from the observation made it is clearly shown that there is an intravascular pressure difference with a change in height.

萃取温度及溶剂对活性炭性能的影响

为了进一步提升活性炭的性能,以褐煤为原料对不同萃取工艺下活性炭的基础结构和电化学性能进行对比。根据实验需求确定的实验方案,重点对萃取剂和萃取温度进行确定,并设计了工艺路线;基于实验方案分别验证了不同萃取温度和萃取剂下活性炭的结构和电化学性能,研究成果将应用于活性炭的工业生产制备。

高表面活性炭制备工艺的优化

为解决化学活化法制备高表面活性炭成本高、能耗大的问题,在对高表面活性炭制备工艺简单概述的基础上,结合实践生产对当前活化比条件下的生产工艺参数进行调试;为达到降低能耗和生产成本的目的对活化比参数以及活化剂添加时间点进行优化,最终达到产品比表面积等指标满足要求的基础上降低生产成本的目的。

Hydromagnetic Squeezing Nanofluid Flow between Two Vertical Plates in Presence of a Chemical Reaction

In this study, Hydromagnetic Squeezing Nanofluid flow between two vertical plates in presence of a chemical reaction has been investigated. The governing equations were transformed by similarity transformation and the resulting ordinary differential equations were solved by collocation method. The velocity, temperature, concentration and magnetic induction profiles were determined with help of various flow parameters. The numerical scheme was simulated with aid of MATLAB. The results showed that increasing the squeeze number only boosts velocity and concentration while lowering temperature. Conversely, increasing the Hartmann number, Reynold’s magnetic number, Eckert number and Thermal Grashof number generally increases temperature but decreases both velocity and concentration. Chemical reaction rate and Soret number solely elevate concentration while Schmidt number only reduces it. The results of this study will be useful in the fields of oil and gas industry, plastic processing industries, filtration, food processing, lubrication system in machinery, Microfluidics devices for drug delivery and other related fields of nanotechnology.

Heat and Mass Transfer for a Nanofluid Flow in Fluidized Bed Dryer in Presence of Induced Magnetic Field

This research entails the study of heat and mass transfer of nanofluid flow in a fluidized bed dryer used in tea drying processes in presence of induced magnetic field. A mathematical model describing the fluid flow in a Fluidized bed dryer was developed using the nonlinear partial differential equations. Due to their non-linearity, the equations were solved numerically by use of the finite difference method. The effects of physical flow parameters on velocity, temperature, concentration and magnetic induction profiles were studied and results were presented graphically. From the mathematical analysis, it was deduced that addition of silver nanoparticles into the fluid flow enhanced velocity and temperature profiles. This led to improved heat transfer in the fluidized bed dryer, hence amplifying the tea drying process. Furthermore, it was noted that induced magnetic field tends to decrease the fluid velocity, which results in uniform distribution of heat leading to efficient heat transfer between the tea particles and the fluid, thus improving the drying process. The research findings provide information to industries on ways to optimize thermal performance of fluidized bed dryers.

律宗在北京:以清代潭柘寺为中心的考察

北京作为辽金元明清五朝帝都,因其特殊的社会政治背景,使北京佛教在历史上具有重要的地位。潭柘山岫云寺乃京西名刹,清代从震寰照福奉旨住持以来,岫云寺前三代住持,皆是康熙帝钦命,灯灯续焰。自震寰照福律师始,直到民国建立,数百年间,潭柘山岫云寺律师传承有18代。可以说形成了一条法脉清晰、传承有序的律宗谱系,成为清代北京佛教宗派发展史最具特色的一章。透过这一谱系也可折射出清代律门宗统的分灯,以及当时王权对教权的主导。

揿针联合易罐治疗VDT性视疲劳的临床观察

目的探讨揿针结合易罐治疗视频终端综合征(VDT)性视疲劳的临床疗效及对眼部血流动力学的影响。方法纳入符合标准的VDT性视疲劳患者63例,随机分为试验组(31例)和对照组(32例)。试验组给予揿针联合易罐治疗,每周3次,对照组给予七叶洋地黄双苷滴眼液,点双眼,每日3次;2组均观察28 d。观测指标包括眼表疾病指数量表(OSDI)量表、眼部彩色多普勒超声对睫状前动脉(ACA)、视网膜中央动脉(CRA)的流速测定。结果(1)OSDI积分:2组治疗前后比较,差异均统计学意义(t对照组=-13.568,t试验组=-17.178,均P=0.000)。治疗后试验组OSDI总积分低于对照组,差异具有统计学意义(t=-4.708,P=0.000)。(2)眼部血流动力学数值:对照组各血流峰值治疗前后比较,差异均有统计学意义(t_((ACA(PSV)))=13.479,t_((ACA(EDV)))=13.877,t_((CRA(PSV)))=13.681,t_((CRA(PSV)))=11.474,均P=0.000)。试验组各血流峰值治疗前后比较,差异均有统计学意义(t_((ACA(PSV)))=20.285,t_((ACA(EDV)))=16.075,t_((CRA(PSV)))=16.280,t(CRA(EDV))=14.762,均P=0.000)。试验组ACA的收缩期峰值流速(PSV)、舒张末期血流速度(EDV)、视网膜中央动脉(CRA)的PSV峰值均高于对照组,差异均有统计学意义(t_((ACA(PSV)))=5.110,t_((ACA(EDV)))=4.003,t(CRA(PSV))=4.109,均P=0.000)。(3)临床疗效:试验组总有效率为90.32%,高于对照组(78.12%),等级差异具有统计学意义(χ^(2)=20.756,P=0.000)。结论揿针联合易罐疗法具有改善VDT性视疲劳患者的眼部血流状态,使眼部组织结构获得再灌注,恢复视物能力与功能的作用。

从“辨构论治”理念探讨颈肩腰腿痛

在诊治颈肩腰腿痛的过程中借鉴前辈经验并吸收中医理论提出了“辨构论治”的诊疗理念。“辨构论治”诊疗理念分为诊断与治疗两个部分,诊断中,医者要筋骨并重,内外兼顾,做到精确诊断;调衡治疗则对应为理筋、正骨、调衡,做到精简治疗。“辨构论治”诊疗理念时时刻刻都在体现整体性,就“辨构论治”诊疗理念与中医整体性之间的关系进行探讨。

欧姆加热纳米流体中具有热跳现象移动表面的Falkner-Skan流分析

边界层假设下的Falkner-Skan流分析因其在渗流、导热垫、热交换器、油层检测和地热分析等许多工业领域和过程中的广泛应用引起了越来越多的关注。本文主要研究了氧化石墨烯-水纳米流体的Falkner-Skan磁楔流。通过对驻点附近进行分析,研究了可拉伸壁面的速度和热滑现象,以及黏性耗散和欧姆加热对热传输的影响。利用同伦算法说明了相关参数与速度和热传输机理的关系,阐述了Nusselt数和表面摩擦因数的影响。结果表明:温度随着Brinkman数的增长而升高,进一步的热跳则使温度场减小;Hartmann数的增加使热场厚度增大,动量谱厚度减小。该研究对医疗、高温设施、热交换器和机械结构有极大意义。

无痛蜂疗法联合HAART治疗脾肾两虚型AIDS患者的临床疗效研究

目的:探讨无痛蜂疗法联合HAART治疗脾肾两虚型艾滋病(AIDS)患者的临床疗效。方法:选择2020年5月至2022年7月我院收治的80例AIDS患者随机分为观察组与对照组。对照组应用HAART治疗,观察组在对照组基础上应用无痛蜂疗法联合治疗。比较两组治疗效果;比较两组治疗前后免疫功能与生存质量。结果:观察组治疗总有效率为92.50%,高于对照组的75.00%(P<0.05)。治疗后3个月,观察组细胞免疫指标均优于对照组(P<0.05)。治疗后3个月,观察组心理、生理、环境、社会关系项目评分均高于对照组(P<0.05)。结论:无痛蜂疗法联合HAART治疗脾肾两虚型AIDS患者的临床效果较好,可显著改善患者免疫功能,提升其近期生存质量,值得推广应用。

The Effects of Thermal Radiation and Viscous Dissipation on the Stagnation Point Flow of a Micropolar Fluid over a Permeable Stretching Sheet in the Presence of Porous Dissipation

In this paper,the effects of thermal radiation and viscous dissipation on the stagnation–point flow of a micropolar fluid over a permeable stretching sheet with suction and injection are analyzed and discussed.A suitable similarity transformation is used to convert the governing nonlinear partial differential equations into a system of nonlinear ordinary differential equations,which are then solved numerically by a fourth–order Runge–Kutta method.It is found that the linear fluid velocity decreases with the enhancement of the porosity,boundary,and suction parameters.Conversely,it increases with the micropolar and injection parameters.The angular velocity grows with the boundary,porosity,and suction parameters,whereas it is reduced if the micropolar and injection parameters become larger.It is concluded that the thermal boundary layer extension increases with the injection parameter and decreases with the suction parameter.

Radon Measure Solutions to Riemann Problems for Isentropic Compressible Euler Equations of Polytropic Gases

We solve the Riemann problems for isentropic compressible Euler equations of polytropic gases in the class of Radon measures,and the solutions admit the concentration of mass.It is found that under the requirement of satisfying the over-compressing entropy condition:(i)there is a unique delta shock solution,corresponding to the case that has two strong classical Lax shocks;(ii)for the initial data that the classical Riemann solution contains a shock wave and a rarefaction wave,or two shocks with one being weak,there are infinitely many solutions,each consists of a delta shock and a rarefaction wave;(iii)there are no delta shocks for the case that the classical entropy weak solutions consist only of rarefaction waves.These solutions are self-similar.Furthermore,for the generalized Riemann problem with mass concentrated initially at the discontinuous point of initial data,there always exists a unique delta shock for at least a short time.It could be prolonged to a global solution.Not all the solutions are self-similar due to the initial velocity of the concentrated point-mass(particle).Whether the delta shock solutions constructed satisfy the over-compressing entropy condition is clarified.This is the first result on the construction of singular measure solutions to the compressible Euler system of polytropic gases,that is strictly hyperbolic,and whose characteristics are both genuinely nonlinear.We also discuss possible physical interpretations and applications of these new solutions.

Nanoparticle Shape Effect on a Sodium–Alginate Based Cu–Nanofluid under a Transverse Magnetic Field

Sodium-alginate(SA)based nanofluids represent a new generation of fluids with improved performances in terms of heat transfer.This work examines the influence of the nanoparticle shape on a non–Newtonian viscoplastic Cu–nanofluid pertaining to this category.In particular,a stretching/shrinking sheet subjected to a transverse magnetic field is considered.The proposed Cu–nanofluid consists of four different nanoparticles having different shapes,namely bricks,cylinders,platelets,and blades dispersed in a mixture of sodium alginate with Prandtl number Pr=6.45.Suitable similarity transformations are employed to reduce non–linear PDEs into a system of ODEs and these equations and related boundary conditions are solved numerically by means of a Runge–Kutta–Fehlberg(RKF)method.Moreover,analytical solutions are obtained through the application of a MAPLE built–in differential equation solver(Dsolve).The behavior of prominent parameters against velocity and temperature is analyzed.It is found that the temperature increases for all shapes of nanoparticles with the viscoplastic parameter and the Eckert number.