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Control Theory and Technology 2024年第3期22卷 455-467页

作者： r.H.Harsha Nawarathna Yuandan Lin Yuan Wang Department of Mathematical Sciences Florida Atlantic UniversityBoca RatonFL 33431USA

We consider how small delays affect the integral-input-to-state stability(iss)property for a *** result is similar to the input-to-state stability(Iss)result obtained in[1]:the iss property will be preserved in a practical and semi-global manner if the delay interval is small ***,since the iss quantifies the robust stability in terms of a generalized Li norm of the inputs instead of a generalized Loo norm of the inputs for the Iss case,the techniques and proofs for the Iss case do not apply to the iss case *** the proofs in[1]are based on the Lyapunov-razumikhin approach,our proofs are based on the iss-Lyapunov functions for the zero-delay *** addition to the interest by its own in showing how the iss property is affected by small delays,the result also serves to the study of the iss property for singularly perturbed systems.

关键词： Integral-input-to-state stability Nonlinear systems Small delays Lyapunov method

Local Criteria Used by Farmers to Evaluate the Agronomic Performance and the Fertilizing Capacity of Cowpea Varieties: Diversity, Variability and Proximal relation with Agronomic Measurements in Contrasted sahelian Locations

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Agricultural Sciences 2024年第1期15卷 114-131页

作者： Nouhou salifou Jangorzo Abdoul-Aziz saïdou Abou-Soufianou sadda Abdoulaye Moussa Mamoudou Hassane Bil-Assanou Issoufou Département des Sciences du Sol et Télédétection Université Dan Dicko Dankoulodo de Maradi Maradi Niger. Unité Mixte de recherche “Diversité et Adaptation des Plantes” (UMr DAP) Université Dan Dicko Dankoulodo de Maradi Maradi Niger Centre Imaan de Support en recherche Transdisciplinaire (Imaan research) Niamey Niger Institut de recherche pour le Développement Niamey Niger Université Boubacar BA de Tillabéri Tillabéri Niger Département des Sciences et Techniques de Productions Végétales Université Dan Dicko Dankoulodo de Maradi Maradi Niger

When contributing to participatory research, farmers usually appreciate the performance of cowpea varieties using qualitative scores. The score they attribute to each variety are based on local knowledge. The specific criteria they individually use to attribute a score are not well described. The objectives of this work were to: 1) identify and describe exhaustively the local criteria used by farmers to measure the agronomic performance of cowpea;2) assess the variability and statistical structure of these farmer criteria across local contexts;3) and analyze the association between these farmer criteria and the classical agronomic measurement. To achieve these objectives, an augmented block design was implemented across fifteen locations in the regions of Maradi, Dosso and Tillabéri, representing a diversity of local contexts. From a set of 36 cowpea varieties, fifteen varieties were sown per location, including five varieties (controls) common to all locations. In each location, two replicates were sown in randomized Fisher’s blocks. After agronomic measurement and participatory evaluation (scoring of varieties by farmers), a group survey (focus group) was conducted in each location to identify the criteria considered by farmers to found their discretional scoring of varieties during the participatory evaluation. The analysis of the data identified, across locations, thirteen criteria defined by farmers to characterize the agronomic performance of cowpea. Some of these criteria were different according to location. Farmers ranked the three varieties with the best performance for each agronomical trait (Top 3 varieties). A comparison of the farmer ranking with the ranking based on agronomic measurements revealed similarity and complementary between both methods. This study highlighted the importance of considering both local and scientific knowledge in local varietal evaluations.

关键词： Agronomic Performance Participatory research Cowpea Farmers’ Criteria

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

Probing the Bardeen-Kiselev black hole with the cosmological constant caused by Einstein equations coupled with nonlinear electrodynamics using quasinormal modes and greybody bounds

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Communications in Theoretical Physics 2024年第6期76卷 102-119页

作者： S r Wu B Q Wang Z W Long College of Physics Guizhou UniversityGuiyang 550025China College Pharmacy Guizhou University of Traditional Chinese MedicineGuiyang 550025China

In this work,we investigate a static and spherically symmetric Bardeen-Kiselev black hole(BH)with the cosmological constant,which is a solution of the Einstein-non-linear Maxwell field *** compute the quasinormal frequencies for the Bardeen-Kiselev BH with the cosmological constant due to electromagnetic and gravitational *** varying the BH parameters,we discuss the behavior of both real and imaginary parts of the BH quasinormal frequencies and compare these frequencies with the reissner-Nordström-de Sitter BH surrounded by quintessence(rN-dSQ).Interestingly,it is shown that the responses of the Bardeen-Kiselev BH with the cosmological constant and the rN-dSQ under electromagnetic perturbations are different when the charge parameter q,the state parameter w and the normalization factor c are varied;however,for the gravitational perturbations,the responses of the Bardeen-Kiselev BH with the cosmological constant and the rN-dSQ are different only when the charge parameter q is ***,compared with the gravitational perturbations,the electromagnetic perturbations can be used to understand nonlinear and linear electromagnetic fields in curved spacetime *** interesting observation is that,due to the presence of Kiselev quintessence,the electromagnetic perturbations around the Bardeen-Kiselev BH with the cosmological constant damps faster and oscillates slowly;for the gravitational perturbations,the quasinormal mode decays slowly and oscillates *** also study the reflection and transmission coefficients along with the absorption cross section in the Bardeen-Kiselev BH with the cosmological constant;it is shown that the transmission coefficients will increase due to the presence of Kiselev quintessence.

关键词： quasinormal modes greybody factors Bardeen-Kiselev black hole with cosmological constant

Effect of Cr and Co Promoters Addition on Vanadium Phosphate Catalysts for Mild Oxidation of n-Butane

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Journal of Natural Gas Chemistry 2006年第2期15卷 144-148页

作者： Yun hin Taufiq-Yap Putra Laboratory for Catalysis and Technology Department of ChemistryFaculty of ScienceUniversiti Putra Malaysia43400 UPM SerdangSelangorMalaysia

In this study, Cr and Co promoted, as well as unpromoted vanadium phosphate （VPO） catalysts were synthesized by the reaction of V2O5 and o-H3PO4 in organic medium followed by calcination in n-butane/air environment at 673 K. The physico-chemical properties and the catalytic behavior were affected by the addition of Cr and Co dopants. H2-TPr was used to investigate the nature of oxidants in the unpromoted and promoted catalysts. The results showed that both the Cr and Co promoters remarkably lowered the temperature of the reduction peak associated with V^5＋. The amount of oxygen species originated from the active phase, V^4＋, removed was significantly increased for Co and Cr-promoted catalysts. Both Cr and Co dopants improve strongly the n-butane conversion without sacrificing the MA selectivity. A good correlation was observed between the amount of oxygen species removed from V^4＋ phase and the activity for n-butane oxidation to maleic anhydride. This suggested that V^4＋-O was the center for the activation of n-butane.

关键词： n-butane oxidation VPO promoter maleic anhydride TPr

Design of a large-scale model for wind tunnel test of a multiadaptive flap concept

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Chinese Journal of Aeronautics 2024年第2期37卷 58-80页

作者： Mürüvvet Sinem SICIM DEMIrCI rosario PECOrA Metin Orhan KAYA Aeronautical Engineering Department Istanbul Technical UniversityIstanbulTurkey Industrial Engineering Department University of Naples Federico IINapoliItaly

The design and application of morphing systems are ongoing issues compelling the aviation *** Clean Sky-program represents the most significant aeronautical research ever launched in Europe on advanced technologies for greening next-generation *** primary purpose of the program is to develop new concepts aimed at decreasing the effects of aviation on the environment,increasing reliability,and promoting eco-friendly *** ambitions are pursued through research on enabling technologies fostering noise and gas emissions reduction,mainly by improving aircraft aerodynamic *** the Clean Sky framework,a multimodal morphing flap device was designed based on tight industrial requirements and tailored for large civil aircraft *** flap is deployed in one unique setting,and its cross section is morphed differently in take-off and landing to get the necessary extra lift for the specific flight ***,during the cruise,the tip of the flap is deflected for load control and induced drag *** manufacturing the first flap prototype,a high-speed(Ma=0.3),large-scale test campaign(geometric scale factor 1:3)was deemed necessary to validate the performance improvements brought by this novel system at the aircraft *** the other hand,the geometrical scaling of the flap prototype was considered impracticable due to the unscalability of the embedded mechanisms and actuators for shape ***,a new architecture was conceived for the flap model to comply with the scaled dimensions requirements,withstand the relevant loads expected during the wind tunnel tests and emulate the shape transition capabilities of the true-scale *** strategies were developed to effectively morph the model during wind tunnel tests while ensuring the robustness of each morphed configuration and maintaining adequate stiffness levels to prevent undesirable deviations from the intended aerodynamic ***,

关键词： Morphing structures Smart aircraft Morphing flap Adaptive systems Finger-like ribs Wind tunnel tests Large-scale morphing archi-tectures Variable camber airfoil

Deep bed filtration model for cake filtration and erosion

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Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 355-372页

作者： L.I.KUZMINA Y.V.OSIPOV A.r.PESTErEV Department of Applied Mathematics HSE UniversityMoscow 101000Russia Department of Computer Science and Applied Mathematics Moscow State University of Civil EngineeringMoscow 129337Russia

Many phenomena in nature and technology are associated with the filtration of suspensions and colloids in porous media. Two main types of particle deposition,namely, cake filtration at the inlet and deep bed filtration throughout the entire porous medium, are studied by different models. A unified approach for the transport and deposition of particles based on the deep bed filtration model is proposed. A variable suspension flow rate, proportional to the number of free pores at the inlet of the porous medium, is considered. To model cake filtration, this flow rate is introduced into the mass balance equation of deep bed filtration. For the cake filtration without deposit erosion,the suspension flow rate decreases to zero, and the suspension does not penetrate deep into the porous medium. In the case of the cake filtration with erosion, the suspension flow rate is nonzero, and the deposit is distributed throughout the entire porous medium. An exact solution is obtained for a constant filtration function. The method of characteristics is used to construct the asymptotics of the concentration front of suspended and retained particles for a filtration function in a general form. Explicit formulae are obtained for a linear filtration function. The properties of these solutions are studied in detail.

关键词： deep bed filtration cake filtration porous medium particle deposition and erosion analytical solution concentration front

Hybrid LES/rANS Simulations of Compressible Flow in a Linear Cascade of Flat Blade Profiles

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Journal of Thermal Science 2024年第5期33卷 1839-1850页

作者： Jaromír PrIHODA Petr STrAKA David SIMUrDA Petr SIDLOF Jan LEPICOVSKY Institute of Thermomechanics of the Czech Academy of Sciences Dolejskova 1402/518200 Prague 5Czech Republic Aerospace research and Test Centre Beranovych 13019905 PragueCzech Republic Technical University of Liberec Faculty of MechatronicsStudentska 246117 Liberec 1Czech Republic

The paper reports on 3D numerical simulations of unsteady compressible airflow in a blade cascade consisting of flat profiles using a hybrid LES/rANS approach including a transition *** a first step towards simulation of blade flutter in turbomachinery,various incidence angle offsets of the middle blade were *** simulations were run for the flow regime characterized by outlet isentropic Mach number M_(is)=0.5and zero *** results of the LES/rANS simulations(pressure and Mach number distributions)were compared to a baseline rANS model,and to experimental data measured in a high-speed wind *** numerical results show that both methods overpredict flow separation taking place at the leading *** this regard,the hybrid LES/rANS method does not provide superior results compared to the traditional rANS ***,the LES/rANS results also capture vortex shedding from the blunt trailing *** frequency of the trailing edge vortex shedding in CFD simulations matches perfectly the spectral peak recorded during wind tunnel measurements.

关键词： numerical simulation blade cascade hybrid LES/rANS

Multi-objective method of selecting performance-based local climatic zones using binomial logistic regression in warm and humid climate

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Frontiers of Architectural research 2024年第1期13卷 184-200页

作者： G.r.Madhavan Dorairaj Kannamma Department of Architecture National Institute of TechnologyTiruchirappalliTamil Nadu 620015India

Urban agglomeration is a serious concern due to its high energy usage and impact on the local *** countries strive to determine the development path to optimize energy *** present study aims to examine the local climatic zones(LCZs)performance in warm and humid climate through a multi-objective approach for the residential *** performance is assessed by evaluating the urban microclimate and cooling load consumption for both summer and winter months using binomial logistic *** study concludes that LCZ 2_(3)(compact mid-rise with open low-rise)and LCZ 6_(B)(open low-rise with scattered trees)perform better for 80%and 50%of total hours in warm and humid *** also proves the presence of significant performance differences between mid-rise and low-rise *** intra-zonal differences between the climatic variables are higher than the inter-zonal differences due to the impact of land surface temperature(LST).The high aspect ratio and low sky view factor of LCZ 2_(3) help the residents in that morphology in enhancing better thermal comfort and reducing cooling load *** present study contributes to building regulation policymakers by providing information on the suitable morphology for warm and humid climate.

关键词： LCZ Outdoor thermal comfort Cooling load LST and urban morphology indicators

Utilization of Pyrrolic Compounds as Indicators of Secondary Migration for Woodford Oils in the Anadarko Basin, Oklahoma, Usa

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Journal of Earth Science 2024年第5期35卷 1499-1512页

作者： Mu Liu r.Paul Philp Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of Sciences School of Geosciences University of Oklahoma

Migration pathways and distances of the oils in reservoir are thought to affect the distribution of pyrrolic compounds such as carbazole, its alkyl derivatives(alkylated carbazoles) and benzocarbazoles, although other factors, including maturity and depositional environments may also affect the distribution of these organic nitrogen compounds. In this study, 14 oil samples produced from conventional reservoirs in Pauls Valley, south Oklahoma were investigated using organic geochemical techniques. The sterane and hopane fingerprints suggest that most of the oils were sourced from the Devonian Woodford shale. Maturity parameters consistently indicate that the maturity level of the studied samples are all of similar maturity(rc = ～0.7%), suggesting the distribution of the organic nitrogen organic compounds is possibly reflecting variations in relative migration distances. The distribution of alkylcarbazoles revealed a preferential enrichment during migration, with the nitrogen-shielded alkylcarbazole tending to be enriched relative to the nitrogen-semi-shielded alkylcarbozoles particularly in oils produced close to the Arbuckle uplift to the east. Correspondingly, another family of pyrrolic compounds, benzocarbazoles, whose distributions also indicated that the Pauls Valley Woodford oils came from deeper part of the Anadarko Basin as the benzo-[a]/([a]+[c])-carbazole ratios decrease eastwards. In more specific migration systems, although the pyrrolic compound indicators are potentially disturbed by the structural complexes, the general migration directions suggest that the studied oils in Pauls Valley Hunton uplift were sourced from the deep basin area, and migrate upwards in porous sediments due to the buoyancy. This study investigates the feasibility of using pyrrolic compounds to estimate relative migration distances and will aid in the interpretation of migration history by using the distribution of carbazole, alkylated carbazoles, benzocarbazoles isomers in the An

关键词： carbazole migration oil Oklahoma biomarker organic geochemistry

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