检索结果-南通市图书馆

Calibration of DEM Parameters to Simulate a Planetary Ball Mill

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Materials Physics and Chemistry 2022年第7期12卷 155-162页

作者： mohsen mhadhbi Laboratory of Useful Materials National Institute of Research and Physicochemical Analysis Ariana Tunisia

Planetary ball mill is a powerful tool, which has been used for milling various materials for size reduction. The discrete element method (DEM) was used to simulate the dynamics of particle processes in a planetary ball mill. This work includes the calibration of DEM parameters to simulate a planetary ball mill using EDEM Altair 2021.2 software, which provides both faster workflows and results. The iterative input parameters changed to a close correlation between the simulation and experimental results are attained. The results showed that the standard tests could be used to generate various experimental reference values for the calibration. The numerical modeling results agree with theexperimental, indicating that the calibrated parameters are accurate.

关键词： Discrete Element Method (DEM) Calibration Planetary Ball Mill Parameters

Effect of Milling Parameters on DEM Modeling of a Planetary Ball Mill

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Materials Physics and Chemistry 2023年第4期13卷 49-58页

作者： mohsen mhadhbi Laboratory of Useful Materials National Institute of Research and Physicochemical Analysis Ariana Tunisia

The effects of the milling parameters involving shape of powder particles, rotation speed, and ball-to-powder diameter (BPDR) on DEM modeling in the planetary ball mill were investigated. BPDR was varied from 1 to 10. The results revealed that the size and shape of the powder particles do not give a significant change in simulation results when BPDR attains maximum value of 10. The increasing of BPDR leads to the increase of simulation time and size. Hence, the effect of change of the powder particle shape on the calculated data size is not significant. The results also revealed that the increasing rotation speed increases impact energy between powder particles.

关键词： DEM Modeling Milling Parameters Planetary Ball Mill Particles Shape

Simulation of a Laboratory Scale Ball Mill via Discrete Element Method Modelling

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Materials Physics and Chemistry 2021年第10期11卷 167-175页

作者： mohsen mhadhbi Laboratory of Useful Materials National Institute of Research and Physicochemical Analysis Technopole Sidi Thabet Ariana Tunisia

Discrete Element Method (DEM) is a powerful tool for simulating different types of mills. It also used for computing different types of particles such as rocks, grains, and molecules. DEM has been widely used in the field of rock mechanics. In the present work, DEM approach is applied to model the milling media (powder particles and balls) inside a planetary ball mill and to estimate the distribution of particles of a dry powder during milling. In fact, the efficiency of the DEM strongly depends on the input parameters. The DEM simulation results indicated that DEM is a promising tool for the simulation of the dynamic particles motion and interactions within planetary ball mill. These results could be utilized to further develop the synthesis performance, anticipate the reaction, and reduce the wear in the dry milling reactions.

关键词： Modelling Discrete Element Method Milling Media Planetary Ball Mill Simulation

Optimum allocation of FACTS devices in Fars Regional Electric Network using genetic algorithm based goal attainment

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第4期10卷 478-487页

作者： mohsen GITIZADEH mohsen KALANTAR Center of Excellence for Power System Automation and Operation Department of Electrical Engineering Iran University of Science and TechnologyTehran 16844 Iran

This paper presents a novel approach to find optimum locations and capacity of flexible alternating current transmission system (FACTS) devices in a power system using a multi-objective optimization function. Thyristor controlled series compensators (TCSCs) and static var compensators (SVCs) are the utilized FACTS devices. Our objectives are active power loss reduction, newly introduced FACTS devices cost reduction, voltage deviation reduction, and increase on the robustness of the security margin against voltage collapse. The operational and controlling constraints, as well as load constraints, were considered in the optimum allocation. A goal attainment method based on the genetic algorithm (GA) was used to approach the global optimum. The estimated annual load profile was utilized in a sequential quadratic programming (SQP) optimization sub-problem to the optimum siting and sizing of FACTS devices. Fars Regional Electric Network was selected as a practical system to validate the performance and effectiveness of the proposed method. The entire investment of the FACTS devices was paid off and an additional 2.4% savings was made. The cost reduction of peak point power generation implies that power plant expansion can be postponed.

关键词： Flexible alternating current transmission system (FACTS) devices allocation Multi-objective optimization Geneticalgorithm (GA) Goal attainment

Effects of porous material on transient natural convection heat transfer of nano-fluids inside a triangular chamber

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2020年第5期28卷 1203-1213页

作者： mohsen Izadi Mechanical Engineering Department Faculty of EngineeringLorestan UniversityKhorramabadIran

This study numerically investigates the impact of porous materials,nano-particle types,and their concentrations on transient natural convection heat transfer of nano-fluid inside a porous chamber with a triangular *** governing equations of the two-phase mixture model are separated on the computational domain and solved using the Finite Volume Method,taking into account the Darcy–Brinkman model for porous *** was observed that convection heat transfer inside the triangular chamber consists of three stages named initial,transient,and *** features of each step are provided in *** results suggested that the use of a hybrid nano-fluid(water/aluminum oxide-cooper)inside a porous glass material and an increase in volume fraction of nano-particles have adverse effects on heat transfer *** contrast,as the nano-particle volume fraction of the single nano-fluid(water/aluminum oxide)inside the chamber increased,convection heat transfer rate *** the same time,it was observed that the use of both nano-fluids(single and hybrid)in the porous environment of the aluminum foam could improve convection.

关键词： Transient natural convection Mixture model Darcy-Brinlanan model Rayleigh-Benard instability Triangular chamber

Orbital electronic heat capacity of hydrogenated monolayer and bilayer graphene

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2017年第2期26卷 375-381页

作者： mohsen Yarmohammadi Young Researchers and Elite Club Kermanshah Branch Islamic Azad University Kermanshah Ira

The tight-binding Harrison model and Green＇s function approach have been utilized in order to investigate the contribution of hybridized orbitals in the electronic density of states（DOS） and electronic heat capacity（EHC） for four hydrogenated structures, including monolayer chair-like, table-like, bilayer AA- and finally AB-stacked graphene. After hydrogenation, monolayer graphene and bilayer graphene are behave as semiconducting systems owning a wide direct band gap and this means that all orbitals have several states around the Fermi level. The energy gap in DOS and Schottky anomaly in EHC curves of these structures are compared together illustrating the maximum and minimum band gaps are appear for monolayer chair-like and bilayer AA-stacked graphane, respectively. In spite of these, our findings show that the maximum and minimum values of Schottky anomaly appear for hydrogenated bilayer AA-stacked and monolayer table-like configurations, respectively.

关键词： hydrogenated monolayer and bilayer graphene Harrison model electronic heat capacity density of states Green's function

Adaptive Output Feedback Regulation for a Class of Uncertain Feedforward Time-Delay Nonlinear Systems

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2020年第3期33卷 604-621页

作者： BELFEKI mohsen University of Sfax IPEISRoute Menzel ChakerKM 0.5B.P.1172Sfax 3018Tunisia Department of mathematics Alkurmah University collegeTaif UniversitySaudi Arabia

This paper addresses the global output feedback regulation problem for a class of uncertain feedforward time-delay nonlinear *** to the previous works,the nonlinear functions in the class of systems under consideration are dominated by an input-output function multiplied by an unknown parameter and linear unmeasured *** using only one dynamic gain and an appropriate Lyapunov-Krasovskii functionals,it is shown that the closed-loop system is globally asymptotically ***,a numerical example is provided to illustrate the effectiveness of the proposed design scheme.

关键词： Adaptive regulation dynamic gain output feedback uncertain feedforward time-delay systems

Robust Hybrid Control for Ballistic Missile Longitudinal Autopilot

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2011年第6期24卷 777-788页

作者： WAEL mohsen Ahmeda WAEL mohsen Ahmed QUAN Quan Department of Automatic Control School of Automation Science and Electrical Engineering Beihang University Beijing 100191 China State Key Laboratory of Virtual Reality Technology and Systems Beihang University Beijing 100191 China

This paper investigates the boost phase＇s longitudinal autopilot of a ballistic missile equipped with thrust vector control. The existing longitudinal autopilot employs time-invariant passive resistor-inductor-capacitor （RLC） network compensator as a control strategy, which does not take into account the time-varying missile dynamics. This may cause the closed-loop system instability in the presence of large disturbance and dynamics uncertainty. Therefore, the existing controller should be redesigned to achieve more stable vehicle response. In this paper, based on gain-scheduling adaptive control strategy, two different types of optimal controllers are proposed. The first controller is gain-scheduled optimal tuning-proportional-integral-derivative （PID） with actuator constraints, which supplies better response but requires a priori knowledge of the system dynamics. Moreover, the controller has oscillatory response in the presence of dynamic uncertainty. Taking this into account, gain-scheduled optimal linear quadratic （LQ） in conjunction with optimal tuning-compensator offers the greatest scope for controller improvement in the presence of dynamic uncertainty and large disturbance. The latter controller is tested through various scenarios for the validated nonlinear dynamic flight model of the real ballistic missile system with autopilot exposed to external disturbances.

关键词： ballistic missiles attitude control gain-scheduling optimal tuning-control LQ optimal regulators

Assessment of mobile and potential mobile trace elements extractability in calcareous soils using different extracting agents

在线全文

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2020年第1期14卷 109-125页

作者： mohsen Jalali Ziba Hurseresht Department of Soil Science College of AgricultureBu_Ali Sina UniversityHamedanIran

Understanding trace elements mobility in soils,extracting agents,and their relationships with soil components,are essential for predicting their movement in soil profile and availability to plants.A laboratory study was conducted to evaluate extractability of cadmium(Cd),cobalt(Co),copper(Cu),nickel(Ni),and zinc(Zn)from calcareous soils utilizing various extracting agents to be specific CaCU,DTPA,EDTA,HNO3,MgCl2,NaN03,NH4NO3,and *** analysis indicated that DTPA and NH4OAc,HN03 and EDTA,and M gCl2 and NH4NO3 extracting agents yielded comparative values,whereas NaN03 and CaCl2 have shown different behavior than other extracting agents for all studied trace *** speciationof extracted trace elements in solutions indicated that in the CaCl2,NaN03,NH4NO3,and MgCl2 extracting agents most extracted Cd,Co,Ni,Zn,and part f Cu were as free ions and may be re-adsorbed on soils,leading to lower extractability,whereas,in the caseof HNO3 extracting agent,the likelihoodof re-adsorptionof trace elements may be *** resultsof speciationof trace elements using NH4OAc DTPA,and EDTA extracting agents showed that Me-(Acetate)3,Me-(Acetate)2(aq),Me(DTPA)3-3-,Me(EDTA)2-.and MeH(EDTA)-complexes dominated in solutions indicating that the extracted trace elements may not be re-adsorbed on soils,leading to higher *** resultsof this study are useful for short and long-term evaluationsof trace elements mobility and further environmental impacts.

关键词： Mobility Calcareous soils Extracting agents Trace elements