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Experimental Evaluation of Trilateration-Based Outdoor Localizationwith LoRaWAN

Computers, Materials & Continua 2023年第4期75卷 845-862页

作者： saeed Ahmed Magsi Mohd Haris Bin Md Khir Illani Bt Mohd Nawi Muath al Hasan Zaka Ullah Fasih Ullah Khan Abdul saboor Muhammad Aadil siddiqui Department of Electrical and Electronic Engineering Universiti Teknologi PETRONASSeri Iskandar32610Malaysia Balochistan University of Information Technology Engineeringand Management SciencesQuetta37500Pakistan College of Engineering Al Ain UniversityAl Ain64141United Arab Emirates Department of Technology The University of LahoreLahore54000Pakistan High Performance Cloud Computing Centre(HPC3) Universiti Teknologi PETRONASSeri Iskandar32610Malaysia

Long Range Wide Area Network (LoRaWAN) in the Internet ofThings (IoT) domain has been the subject of interest for researchers. Thereis an increasing demand to localize these IoT devices using LoRaWAN dueto the quickly growing number of IoT devices. LoRaWAN is well suited tosupport localization applications in IoTs due to its low power consumptionand long range. Multiple approaches have been proposed to solve the localizationproblem using LoRaWAN. The Expected signal Power (EsP) basedtrilateration algorithm has the significant potential for localization becauseEsP can identify the signal’s energy below the noise floor with no additionalhardware requirements and ease of implementation. This research articleoffers the technical evaluation of the trilateration technique, its efficiency,and its limitations for the localization using LoRa EsP in a large outdoorpopulated campus environment. Additionally, experimental evaluations areconducted to determine the effects of frequency hopping, outlier removal, andincreasing the number of gateways on localization accuracy. Results obtainedfrom the experiment show the importance of calculating the path loss exponentfor every frequency to circumvent the high localization error because ofthe frequency hopping, thus improving the localization performance withoutthe need of using only a single frequency.

关键词： LoRaWAN localization expected signal power(EsP) path loss exponent(PLE) trilateration

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Dispersion equation of magnetoelastic shear waves in irregular monoclinic layer

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Applied Mathematics and Mechanics(English Edition) 2011年第5期32卷 571-586页

作者： A.CHATTOPADHYAY s.GUPTA s.A.sAHU A.K.sINGH Department of Applied Mathematics Indian school of Mines

This paper studies the propagation of horizontally polarized shear waves in an internal magnetoelastic monoclinic stratum with irregularity in lower interface. The stratum is sandwiched between two magnetoelastic monoclinic semi-infinite media. Dispersion equation is obtained in a closed form. In the absence of magnetic field and irregularity of the medium, the dispersion equation agrees with the equation of classical case in three layered media. The effects of magnetic field and size of irregularity on the phase velocity are depicted by means of graphs.

关键词： shear wave magnetoelastic monoclinic irregularity dispersion equation perturbation

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Evaluating the effectiveness of marine actinobacterial extract and its mediated titanium dioxide nanoparticles in the degradation of azo dyes

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Journal of Environmental sciences 2014年第4期26卷 775-782页

作者： s Priyaragini s Veena D swetha L Karthik G Kumar K V Bhaskara Rao Molecular and Microbiology Research Laboratory Environmental Biotechnology Division School of Bio Sciences and Technology VIT University

Aim of the present study was to synthesize titanium dioxide nanoparticles （YiO2 NPs） from marine actinobacteria and to develop an eco-friendly azo-dye degradation method. A total of five actinobacterial isolates were isolated from Chennai marine sediments, Tamilnadu, India and analyzed for the synthesis of TiO2 NPs using titanium hydroxide. Among these, the isolate PsV 3 showed positive results for the synthesis of TiO2 NPs, which was confirmed by UV analysis. Further characterization of the synthesized TiO2 NPs was done using XRD, AFM and FI＇-IR analysis. Actinobacterial crude extract and synthesized TiO2 NPs was found efficient in degrading azo dye such as Acid Red 79 （AR-79） and Acid Red 80 （AR-80）. Degradation percentage was found to be 81% for AR-79, 83% for AR-80 using actinobacterial crude extract and 84% for AR-79, 85% for AR-80 using TiO2 NPs. Immobilized actinobacterial ceils showed 88% for AR-79 and 81% for AR- 80, dye degrading capacity. Degraded components were characterized by FT-IR and GC-Ms analysis. The phytotoxicity test with 500 μg/mL of untreated dye showed remarkable phenotypic as well as cellular damage to Tagetes erecta plant. Comparatively no such damage was observed on plants by degraded dye components. In biotoxicity assay, treated dyes showed less toxic effect as compared to the untreated dyes.

关键词： actinobacteria azo dye degradation ZiO2 NPs biotoxicity Tagetes erecta

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Experimental data for high-temperature decomposition of natural celadonite from banded iron formation

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Chinese Journal Of Geochemistry 2015年第4期34卷 507-514页

作者： K.A.savko s.M.Piliugin N.s.Bazikov Voronezh state University Universitetskaya Square

Three experiments were set up to evaluate conditions for the high-temperature decomposition of celadonite from a banded iron formation in an alumina-free system and identify its decomposition products. It was estimated that at 650 and 750 °C, with a Ni Ni O buffer and pressure of 3 kbar, celadonite completely decomposes and the decomposition products were tetraferribiotite, magnetite and quartz. Under more oxidizing conditions(hematite-magnetite buffer instead of Ni Ni O), ferrous potassium feldspar sanidine forms instead of *** the celadonite decomposition in oxidizing conditions more magnesian and aluminous tetraferribiotite,along with ferrous sanidine, are formed than at reducing conditions.

关键词：实验数据高温分解磁铁矿条带状天然分解产物氧化条件分解过程

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Entropy analysis of unsteady magneto-nanofluid flow past accelerating stretching sheet with convective boundary condition

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Applied Mathematics and Mechanics(English Edition) 2015年第12期36卷 1593-1610页

作者： s.DAs s.CHAKRABORTY R.N.JANA O.D.MAKINDE Department of Mathematics University of Gour Banga Department of Applied Mathematics Vidyasagar University Faculty of Military science Stellenbosch University

The unsteady laminar magnetohydrodynamics （MHD） boundary layer flow and heat transfer of nanofluids over an accelerating convectively heated stretching sheet are numerically studied in the presence of a transverse magnetic field with heat source/sink The unsteady governing equations are solved by a shooting method with the Runge-Kutta- Fehlberg scheme. Three different types of water based nanofluids, containing copper, aluminium oxide, and titanium dioxide, are taken into consideration. The effects of the pertinent parameters on the fluid velocity, the temperature, the entropy generation num- ber, the Bejan number, the shear stress, and the heat transfer rate at the sheet surface are graphically and quantitatively discussed in detail. A comparison of the entropy generation due to the heat transfer and the fluid friction is made with the help of the Bejan number. It is observed that the presence of the metallic nanoparticles creates more entropy in the nanofluid flow than in the regular fluid flow.

关键词： unsteady MHD flow nanofluid heat source/sink entropy generation Bejan number

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Irreversibility analysis of unsteady couette flow with variable viscosity

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Journal of Hydrodynamics 2015年第2期27卷 304-310页

作者： EEGUNJOBI A.s. MAKINDE O.D. TsHEHLA M.s. FRANKs O. Department of Mathematics and statistics Namibia University of Science and Technology Faculty of Military science Stellenbosch University Faculty of Engineering Built Environment and Information Technology Nelson Mandela Metropolitan University Faculty of Military science Stellenbosch University

This paper investigates numerically the inherent irreversibility in unsteady generalized Couette flow between two parallel plates with variable viscosity. The nonlinear governing equations are derived from the Navier-stokes equations and solved numerically using a semi-discretization finite difference method together with the Runge-Kutta-Fehlberg integration scheme. The profiles of velocity and the temperature obtained are used to compute the entropy generation number, Bejan number, skin friction and Nusselt number. The effects of embedded parameters on entire flow structure are presented graphically and discussed quantitatively.

关键词： parallel plates variable viscosity heat transfer Couette flow entropy generation

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Lubricatio mechanism of a strong tribofilm by imidazolium ionic liquid

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Friction 2023年第3期11卷 425-440页

作者： Wei sONG Jie ZHANG sophie CAMPEN Jincan YAN Hongbing JI Janet s.s.WONG Department of Mechanical Engineering Imperial College LondonLondon SW72AZUK Fine Chemical Industry Research Institute Schoolof Chemistry Sun Yat-sen UniversityGuangzhou 510275China school of Chemical and Environmental Engineering Shanghai Institute of TechnologyFengxianShanghai 201418China school of Chemical Engineering Guangdong University of Petrochemical TechnologyMaoming 525000China

Friction modifiers(FMs)are surface-active additives added to base fluids to reduce friction between rubbing *** effectiveness depends on their interactions with rubbing surfaces and may be mitigated by the choice of the base *** this work,the performance of an imidazolium ionic liquid(ImIL)additive in polyethylene-glycol(PEG)and 1,4-butanediol for lubricating steel/steel and diamond-like-carbon/diamond-like carbon(DLC-DLC)contacts were ***-containing PEG reduces friction more effectively in steel-steel than DLC-DLC *** contrast,adding ImIL in 1,4-butanediol results in an increase in friction in steel-steel *** from the Raman spectroscopy,X-ray photoelectron spectroscopy(XPs),and focused ion beam-transmission electron microscopy(FIB-TEM)reveal that a surface film is formed on steel during rubbing in ImIL-containing *** film consists of two *** top layer is composed of amorphous carbon and are easily removed during *** bottom layer,which contains iron oxide and nitride compound,adheres strongly on the steel *** film maintains its effectiveness in a steel-steel contact even after ImIL additives are *** film is not observed in 1,4-butanediol where the adsorption of ImIL is hindered,as suggested by the quartz crystal microbalance(QCM)*** benefit is observed when the base fluid on its own is sufficiently lubricious,as in the case of DLC *** work provides fundamental insights on how compatibilities among base fluid,FM,and rubbing surface affect the performance of IL as surface active *** reveals the structure of an ionic liquid(IL)surface film,which is effective and *** knowledge is useful for guiding future IL additive development.

关键词： ionic liquid(IL) polyethylene-glycol(PEG) friction modifiers(FMs) tribofilm

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separation of ^(152+154)Eu,^(90)sr from radioactive waste effluent using liquid–liquid extraction by polyglycerol phthalate

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Nuclear science and Techniques 2018年第6期29卷 76-84页

作者： M.F.Attallah s.E.Rizk s.A.shady Analytical Chemistry and Control Department Hot Laboratories Center Atomic Energy Authority of Egypt Chemistry of Nuclear Fuel Department Hot Laboratories Center Atomic Energy Authority of Egypt Technology of Nuclear Fuel Department Hot Laboratories Center Atomic Energy Authority of Egypt

A new polyglycerol phthalate extractant was prepared and characterized using Fourier transform infrared spectroscopy, proton nuclear magnetic resonance(~1H NMR) spectroscopy, and thermogravimetric analysis. A preliminary study of the extraction of long-lived(^(90) sr and ^(152+154)Eu) and short-lived(^(90) Y) radionuclides by polyglycerol phthalate was performed. The influence of different diluents, concentration of the acid, type of acid, and various interfering ions was explored. The stripping of ^(152+154)Eu radionuclide was studied by using different acid solutions, and it was found that sulfuric acid was the ideal acid for this purpose. Furthermore,^(152+154)Eu was extracted from the fission products(^(90) sr) and the extraction% of^(90) sr was found to improve in the presence of interfering ions.

关键词：放射性核种抽取液体 Fourier 分离浪费光谱学 NMR

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Flat solutions of some Non-Lipschitz Autonomous semilinear Equations May be stable for N≥3

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Chinese Annals of Mathematics,series B 2017年第1期38卷 345-378页

作者： Jesús Ildefonso DIAZ Jesús HERNaNDEZ Yavdat IL'Y AsOV Instituto de Matematica Interdisciplinar Universidad Complutense de Madrid 28040 MadridSpain. Departamento de Matematicas Universidad Autonoma de Madrid 28049 CantoblancoMadridSpain. Institute of Mathematics Ufa Science Center of RAS 112Chernyshevsky StrUfa 450077Russia.

The authors prove that flat ground state solutions(i.e. minimizing the energy and with gradient vanishing on the boundary of the domain) of the Dirichlet problem associated to some semilinear autonomous elliptic equations with a strong absorption term given by a non-Lipschitz function are unstable for dimensions N = 1, 2 and they can be stable for N ≥ 3 for suitable values of the involved exponents.

关键词： semilinear elliptic and parabolic equation strong absorption spectral problem Nehari manifolds Pohozaev identity Flat solution Linearized stability Lyapunov function Global instability

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Diversity and structural composition of species in dipterocarp forests:a study from Fasiakhali Wildlife sanctuary, Bangladesh

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Journal of Forestry Research 2018年第5期29卷 1241-1249页

作者： s.C.Das M.s.alam M.A.Hossain Institute of Forestry and Environmental sciences University of Chittagong

Fasiakhali Wildlife sanctuary is a protected area composed of tropical remnant rainforest that harbor substantial number of large,old Garjan（Dipterocarpus spp.）*** present study assessed composition,structure and diversity of the species in this protected area.A total of 32 trees species were recorded with DBH ≥ 11 cm belonging to 24 genera and 19 *** forest is low in plant diversity as represented by shannon–Wiener diversity and simpson Dominance *** turbinatus was the most dominant species with maximum relative density,frequency,dominance,and importance value *** firmum and Tectona grandis followed in terms of *** structural composition indicated higher number of individuals in the medium growth classes（41 to 〈 511 cm DBH and 16–20 m height ranges）,whereas *** was the only species that dominated most of the growth *** stem density in lower growth classes indicated meager recruitment of regeneration which may be due to lower annual precipitation,increased grazing and *** study will help to understand the patterns of tree species composition and diversity in the remnant dipterocarp forests of *** will also contribute to identifying threatened plants to undertake *** based conservation and sustainable management of the Fasiakhali Wildlife sanctuary.

关键词： species diversity structural composition Protected area Importance value index Cluster analysis

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