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the Radcliffe Wave Parameters from Data on Open Star Clusters

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Research in Astronomy and Astrophysics 2024年第3期24卷 106-109页

作者： V.V.Bobylev A.t.Bajkova Pulkovo Astronomical Observatory St-Petersburg 196140Russia

A spectral analysis of the vertical positions and velocities of 374 open star clusters(OSCs)was carried *** took these OSCs from the Hunt and Reffert catalog;they have an average age of about 10 million years,and are located on the galactic plane XY in a narrow zone inclined by 25°to the galactic axis *** following estimates of the parameters of the Radcliffe wave were obtained:(a)the maximum value in periodic perturbations of vertical coordinates Z_(max)=92±10pc with the wavelength of these perturbations λ_(z)=4.82±0.09 kpc;(b)the maximum value of the velocity of vertical disturbances Wmax=4.36±0.12km s^(-1) with disturbance wavelengthλ_(W)=1.78±0.02 *** that the results of the vertical velocity analysis are first-class in accuracy and completely new.

关键词： (Galaxy) local interstellar matter-Galaxy structure-(Galaxy) solar neighborhood

Voids size distribution in gelled waxy crude oil under dynamic and static cooling

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Petroleum Research 2024年第1期9卷 109-114页

作者： Girma t.Chala Shaharin A.Sulaiman Department of Mechanical Engineering(Well Engineering) International College of Engineering and ManagementP.O.Box 2511C.P.O Seeb 111MuscatOman Department of Mechanical Engineering Universiti Teknologi PETRONASBandar Seri Iskandar37500TronohPerakMalaysia

Waxy crude oil is known for its high wax contents that can potentially result in gelling following sufficient cooling of the transportation line in the subsea bed at offshore *** gelling over the entire lines requires an accurately predicted restart pressure to restart the clogged and idle ***,the common way of predicting the restart pressure has been reported to result in over-designed and predicted piping *** research findings evidenced the formation of voids which would reduce the restart pressure *** study conducted in this paper is aimed at investigating the voids size distribution in gelled crude oil across and along transportation *** of experiments simulating crude oil transportation during both static and dynamic cooling were *** gelled crude oil below the pour point temperature was then scanned using a Magnetic Resonance Imaging(MRI)system to detect the voids *** resulting voids at each scanning cross-section were quantified,and their distributions were *** was observed that dynamic cooling had minimal impacts on the voids size difference along the pipeline with the difference in voids areas within 10 mm^(2) to be twice and uniform for the entire flow rates ***,voids size in statically cooled waxy crude oil was found to be highly distributed with a maximum of 6 voids size distribution in 10 mm2 *** low-end temperature had the highest size difference while the difference was decreasing with higher end *** study shows that the voids amount in dynamically cooled waxy crude oil could also be estimated with lower numbers of cross-sectional voids ***,the higher cross-sectional voids detection is recommended while estimating voids in statically cooled waxy crude oil.

关键词： Gelled crude oil Voids size distribution Dynamic cooling Static cooling

Mathematical modelling of ball and plate system with experimental and correlation function-based model validation

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Control theory and technology 2024年第2期22卷 326-341页

作者： t.R.Dil Kumar S.J.Mija Department of Electrical Engineering National Institute of Technology CalicutKozhikode673601KeralaIndia

the ball and plate system is an inherently nonlinear under actuated benchmark system used for validating the performance of various control schemes. A mathematical model depicting the dynamics close to that of the system is very much required for such a test bed. In this correspondence, the complete nonlinear model, a simplified nonlinear model, and a linearized model of the ball and plate system are developed. the system comprises a ball and plate mechanism and a rotary servo unit. the ball and plate mechanism is modelled using the Euler–Lagrange method, whereas the rotary servo subsystem is modelled from the first principles. the nonlinear model of the combined system is developed by including the dynamics of the servo motor with gear and rolling resistance between the ball and the plate. the simplified nonlinear model of the system is obtained with suitable assumptions. the model is linearized around the operating point using the Jacobian. the validity of the developed models is investigated through correlation function analysis. the open-loop response of the three models, viz., nonlinear, simplified nonlinear, and linearized models, is analyzed in the MAtLAB/Simulink platform. Since the open-loop system is unstable, the experimental validation of the model is performed with a double-loop PSO (particle swarm optimization) PID control scheme.

关键词： Ball and plate system Correlation function Model validation Particle swarm optimization(PSO) PSO PID controller

Evaluation of slope stability through rock mass classification and kinematic analysis of some major slopes along NH-1A from Ramban to Banihal, North Western Himalayas

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 167-182页

作者： Amit Jaiswal A.K.Verma t.N.Singh Department of Civil and Environmental Engineering Indian Institute of Technology PatnaPatna801106India

the network of Himalayan roadways and highways connects some remote regions of valleys or hill slopes,which is vital for India’s socio-economic *** to natural and artificial factors,frequency of slope instabilities along the networks has been increasing over last few *** of stability of natural and artificial slopes due to construction of these connecting road networks is significant in safely executing these roads throughout the *** rock mass classification methods are generally used to assess the strength and deformability of rock *** study assesses slope stability along the NH-1A of Ramban district of North Western *** structurally and non-structurally controlled rock mass classification systems have been applied to assess the stability conditions of 14 *** evaluating the stability of these slopes,kinematic analysis was performed along with geological strength index(GSI),rock mass rating(RMR),continuous slope mass rating(CoSMR),slope mass rating(SMR),and Q-slope in the present *** SMR gives three slopes as completely unstable while CoSMR suggests four slopes as completely *** stability of all slopes was also analyzed using a design chart under dynamic and static conditions by slope stability rating(SSR)for the factor of safety(FoS)of 1.2 and 1 respectively.Q-slope with probability of failure(PoF)1%gives two slopes as stable *** slope angle has been determined based on the Q-slope safe angle equation and SSR design chart based on the *** value ranges given by different empirical classifications were RMR(37-74),GSI(27.3-58.5),SMR(11-59),and CoSMR(3.39-74.56).Good relationship was found among RMR&SSR and RMR&GSI with correlation coefficient(R 2)value of 0.815 and 0.6866,***,a comparative stability of all these slopes based on the above classification has been performed to identify the most critical slope along this road.

关键词： Rock mass classification Kinematic analysis Slope stability Himalayan road Static and dynamic conditions

Near resonance vibration isolation on a levered-dual response(LEDAR)Coulomb-damped system by differential preloads/offsets in linear springs

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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 1033-1050页

作者： t.I.tOLUWALOJU C.K.tHEIN D.HALIM Department of Mechanical Materials and Manufacturing EngineeringUniversity of Nottingham Ningbo ChinaNingbo 315100Zhejiang ProvinceChina Nottingham Ningbo China Beacons of Excellence Research and Innovation Institute University of Nottingham Ningbo ChinaNingbo 315048Zhejiang ProvinceChina

the levered-dual response(LEDAR)Coulomb-damped system attains near resonant vibration isolation by differential preloads/offsets in linear *** takes the advantages of both the preloads/offsets in linear springs and the guiderail friction for realizing different levels of vibration *** isolation capacities are investigated on the strategies with both the horizontal and vertical guiderails,with the horizontal rail only,and without *** compressive preloads generally result in the consumption of most of the initial excitation energy so as to overcome the potential *** isolation onsets at the frequency ratio of 1∓0.095 on the left-hand side(LHS)and the right-hand side(RHS)of the lever are relative to the load plate *** observed near resonant isolation thus makes the LEDAR system a candidate for the isolation of the mechanical systems about resonance while opening a path for simultaneous harvesterisolation functions and passive functions at extreme frequencies.

关键词： lever ratio Coulomb damping preload tension/compression isolation band/depth offset potential

Development of endemicity and conservation importance indices for tropical forests and the floral diversity assessment of *** in Benguet,Philippines

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Journal of Mountain Science 2024年第3期21卷 786-804页

作者： Johndale Rein t.BULLONG Jim P.SILVERIO Joanna I.ALAFAG Maricel A.GURON Jones t.NAPALDEt Department of Environmental Science Benguet State UniversityLa Trinidad 2601Philippines Department of Biology Benguet State UniversityLa Trinidad 2601Philippines

the scientific community faces the challenge of measuring progress toward biodiversity targets and indices have been traditionally ***,recent inventories in secondary tropical mountain forests using traditional biodiversity indices have yielded results that are indistinct with primary *** shows the need to develop complementary indices that goes beyond species count but integrates the distribution and conservation status of the *** study developed endemicity and conservation importance index for tropical forest that incorporated the distribution and conservation status of the *** indices were applied to ***,a remnant primary mossy forest in Buguias,Benguet,Philippines,that resulted to endemicity index of 81.07 and conservation importance index of *** these with secondary forest sites with comparable Shannon-Wiener,Simpson,Evenness and Margalef’s indices,our endemicity and conservation indices clearly differentiates primary forest(our study site)with higher values from secondary forests with much lower ***,we are proposing these indices for a direct but scientifically-informed identification of specific sites for conservation and protection in tropical ***,our study documented a total of 168 vascular plant species(79 endemic and 12 locally threatened species)in *** are of tropical elements for both generic and species levels with some temperate elements that could be attributed to the site's high elevation and semi-temperate *** are important baseline information for conservation plans and monitoring of tropical mossy forests.

关键词： Endemicity index Conservation importance index Cordillera Central Range Floristic element Jaccard Index of Similarity

Grazing Pressure and Plant Functional types in Puna Highlands,Northwestern Argentina

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Phyton-International Journal of Experimental Botany 2024年第5期93卷 1067-1080页

作者： Quiroga Mendiola Mariana tálamo Andrés IPAF NOA—INtA(National Institute for Agricultural technology) Posta de HornillosJujuy4622Argentina Facultad de Ciencias Naturales Universidad Nacional de SaltaSalta4400Argentina Instituto de Bio y Geociencias del NOA(IBIGEO) UNSa-CONICET.Laboratorio de Ecología Aplicada a la Conservación(LEAC)Facultad de Ciencias NaturalesUniversidad Nacional de SaltaSalta4400Argentina Maestría en Gestión Ambiental Escuela de NegociosUniversidad Católica de Salta(UCASAL)Salta4400Argentina

the Puna grasslands support grazing systems that produce meat and wool in multi-species herds,especially from llama(Lama glama)and ***,it is yet unknown whether grazing pressure can modify grassland structure and Plant Functional types diversity and cover in Puna *** analyzed the relationship between grazing pressure and Plant Functional types by comparing transects located near stockyards(high grazing pressure)and far from them(low pressure)and by evaluating the relationship between the Plant Functional types cover to a Grazing Pressure Index(GPI).this index incorporates the heterogeneity of traditional pastoral *** two ecological sites(Ciénego and tolar),we sampled paired transects(near-far).Plots near and far from corrals were similar in all the variables measured except for plots in tolar,which tend to have higher total cover,possibly due to fecal fertilization near ***,we recorded an increase in total cover and grass cover at higher GPI in Ciénego,while in tolar we found lower values of total cover and herbaceous dicotyledonous cover at intermediate intensities of *** only negative relationship found was the cover of clonal and non-clonal shrubs,possibly explained by the greater use of these shrubs as firewood near *** summary,our study does not show important changes in Plant Functional types as a function of grazing pressure in the studied grasslands probably because grazing pressure is diluted or diminished when livestock rotates in different areas and grazing durations ***,the long grazing history with which the Puna has evolved could also contribute to the co-structuration between native vegetation and livestock farming.

关键词： Natural grasslands Puna herbivory ecological perturbation

Energy exchange between charged relativistic fluids in f(t) gravity

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Communications in theoretical Physics 2024年第10期76卷 108-120页

作者： Z Yousaf U A Khokhar Nasser Bin turki t Suzuki Department of Mathematics University of the Punjab Quaid-i-Azam Campus Department of Mathematics College of Science King Saud University Department of Regional Management Faculty of Management Fukushima College

this study focuses on the effects of a polytropic fluid on a charged gravitational source within f(t) gravity, where t is the torsion scalar. We investigate how the electromagnetic field affects the flow of energy in spherically symmetric and static celestial objects that contain relativistic fluids. By using the gravitational decoupling technique, we analyze the effects of polytropic fluid on the dynamics of the gravitational source, accompanied by the matching of the interior geometry with an exterior at the hypersurface Σ. Finally, with the help of the tolman ⅡV solution, we observe the conduct of energy conditions with the existence of charge using f(t)field equations and got the intended outcomes.

关键词： anisotropy complexity energy exchange hydrodynamics self-gravitating systems

Impacts of multiple demand-side management strategies on microgrids planning: a literature survey

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CLEAN ENERGY 2024年第1期8卷 36-54页

作者： Elazab, Rasha Abdelnaby, Ahmed t. Ali, A. A. Helwan Univ Fac Engn Elect Power & Machines Dept Cairo Egypt

Demand-side management (DSM) schemes play a crucial role in managing renewable energy generation and load fluctuations by utilizing demand-response programmes (DRPs). this paper aims to provide a detailed overview of DRPs that help microgrid operators to keep costs and reliability within acceptable ranges. Additionally, this review paper provides a detailed economic load model for DRPs based on initial load, demand-response (DR) incentive, DR penalty and elasticity coefficients. this article also aims to guide researchers in identifying research gaps in DSM applications in microgrids by comparing various DSM schemes from different countries and regions in terms of DSM strategies, objective functions and optimization techniques. Furthermore, this study analyses the impact of DRPs on microgrid configuration from the perspective of utilities and customers, considering technical and economic performance metrics. As a result, it can be concluded that none of the studied cases provides models or guidelines for choosing appropriate DSM schemes that consider different consumer interests or load-type features. Furthermore, a few researchers have addressed the features of a modern price-based DR strategy, renewable generation-based dynamic pricing DR, which offers higher customer satisfaction than traditional DRPs. [GRAPHICS] .

关键词： demand-side management optimal sizing demand-response strategies renewable generation-based dynamic pricing tIME-OF-USE ENERGY MANAGEMENt RENEWABLE ENERGY RESPONSE PROGRAM RELIABILItY PARtICIPAtION tECHNOLOGY CHALLENGES OPERAtION SYStEMS