MOST STABLE MOTION DESIGN OF THE MOBILE ROBOT IN THE SPECIFIED PATH
A.A.
Moosavian
author
Shahab
Hoseyni
استان مرکزی- محلات - نیم ور - خ طالقانی - گلستان 16 - منزل سید محمود حسینی
author
text
article
2013
per
In this research, a method for stabilization of the robot motion on the specified path is presented. Also a new hybrid system that is capable of stabilizing the unstable condition is investigated. To enable a robot to maintain stability or stabilizing unstable conditions, spatial parallel mechanism between the moving base and manipulators is used. The parallel mechanism does not have any rotation relative to mobile base and only has translational motions. Carrying more loads by robots is one of the main demands. Increasing the robot load may cause the robot tips over. The robot can carry more loads using a parallel mechanism as a base for serial manipulator. In this paper, moment-height stability measure is explained. Holonomic and nonholonomic constraints of the system are derived and then kinematics and dynamics of the proposed robot is derived. The mathematical model is validated by simulation in ADAMS software. In a maneuver a part of the path that is unstable is stabled. Also most stable motion is designed for the whole of path.
Journal of Modeling in Engineering
دانشگاه سمنان
2008-4854
11
v.
33
no.
2013
1
14
http://modelling.journals.semnan.ac.ir/article_1640_86a4249912a04dfc26f0d3c2c78169d4.pdf
dx.doi.org/10.22075/jme.2017.1640
SINGLE OBJECTIVE OPTIMIZATION OF CLOSED BALL MILLING CIRCUIT OF ESFORDI PHOSPHATE PLANT
Z.S.
Mirzaei
author
A.
Farzanegan
author
text
article
2013
per
The subject of this project is optimization of closed ball-mill circuit at Esfordi phosphate plant, based on integration of process simulation and genetic algorithm (GA) concepts. The BMCSÂ® (BMCS-based Modular Comminution Simulator) under MATLAB software was used in this investigation to search for the optimal operating condition of the comminution circuit so that a pre-defined process goal can be achieved. The search process is done using genetic algorithm. The main problem in the circuit is the existence of fine particles with a high degree of iron content in the hydrocyclone underflow stream which is recycled to the ball mill unit. These particles are subjected to over grinding and cause some problems in downstream processes, i.e., flotation, which leads to a low production quality. Therefore, the goal of this project was set to improve ore grinding in ball mill unit and increase the efficiency of particle size classification by hydrocyclone unit. The GA optimization was done in a single objective form that the optimization goal was to achieve a pre-defined particle size for overflow or underflow streams separately. The circuit simulations optimized by GA produced various results and conditions that each of them can be recommended for plant testing and performance improvements.
Journal of Modeling in Engineering
دانشگاه سمنان
2008-4854
11
v.
33
no.
2013
15
25
http://modelling.journals.semnan.ac.ir/article_1641_82d890fad8c93ff201ea6430f7ebaadd.pdf
dx.doi.org/10.22075/jme.2017.1641
COMPARISON OF PERFORMANCE OF RBF AND MLP NEURAL NETWORKS FOR RESULTS OF SIMULTANEOUS HEAT & MASS TRANSFER
F.
Karimi Zad Gohari
author
A.
Shahsavand
author
text
article
2013
per
In most of the chemical engineering processes, the phenomena of mass and heat transfer are among their inseparable parts. In the present paper, simultaneous heat and mass transfer has been studied experimentally by a laboratory setup. In this apparatus, the existence of condensation and evaporation created due to heat transfer causes mass transfer and finally influences the coefficient of heat transfer. Also, mass transfer changes heat distribution in heat transfer phenomena that causes total change in heat flux. Thus, in this apparatus, some experiments have been carried out through changing different parameters such as temperature and flow rate for two fluids, water and air. Also in this paper, it is tried to compare the function of these systems with each other and the results acquired from the experiments as well as the capacity of these systems in analyzing the results were studied through artificial neural networks. From among the neural networks used in this paper, we may refer to RBF, MLP networks. The studies indicate that the MLP network is not able to predict properly due to lack of any facility for noise filtration and RBF network has the best function due to having a stronger theoretical basis.
Journal of Modeling in Engineering
دانشگاه سمنان
2008-4854
11
v.
33
no.
2013
27
43
http://modelling.journals.semnan.ac.ir/article_1642_a6a62b4f66efe7b1d89468277f6438d8.pdf
dx.doi.org/10.22075/jme.2017.1642
PRODUCTIVITY IMPROVEMENT OF A TUBULAR SOLAR STILL, USING CFD SIMULATION
E.
Fotouhi Bafghi
یزد- بافق- خیابان وحشی بافقی- فرعی22- کوچه ایثار.
author
N.
Rahbar
author
N.
Rahbar
author
J.A.
Esfahani
author
text
article
2013
per
In recent years, due to scarcity of drinking water, scientists have conducted many studies to find several optimization methods for solar desalination systems. Solar stills use clean solar energy without any noise and any pollution. Therefore, they can be the best alternative for conventional desalination devices. The intention of this work is the CFD simulation of two-dimensional laminar natural convection inside a tubular solar still. In this manner, the governing equations of mass, momentum, energy and concentration are solved by a finite volume method. Furthermore, we investigate the effects of trough geometry, cover radius, water depth, and position of the trough on the productivity of the tubular solar still. The results are in a good agreement with the results of previous reported experimental data. The results showed that the tubular solar still with circular trough is the best choice to have a maximum productivity. Moreover, the best height between the trough and the cover was found at 124.9mm, and the optimum water-depth and optimum cover-radius are 48mm and 80 mm, respectively.
Journal of Modeling in Engineering
دانشگاه سمنان
2008-4854
11
v.
33
no.
2013
45
56
http://modelling.journals.semnan.ac.ir/article_1643_6a3f6cf0803912ada388aff035a1e707.pdf
dx.doi.org/10.22075/jme.2017.1643
NUMERICAL INVESTIGATION OF NATURAL CONVECTION AROUND A CIRCULAR CYLINDER PLACED IN A CAVITY FILLED WITH NANOFLUID BY CHANGING THE LOCATION AND RADIUS
A.
Fereidun
author
A.A.
Abbasian Arani
author
A.A.
Abbasian Arani
author
M.
Hemmat Esfe
author
A.
Zare Ghadi
author
text
article
2013
per
In this article, a numerical study was conducted to examine the effect of location and diameter of the inner cylinder on laminar natural convection flow fields and temperature distribution around a circular body inserted square cavity. In order to study different situations, the radius of obstacle varied from 0.2 to 0.3 length of square, the Rayleigh number between 103 to 107 and solid contraction of nanofluid with diameter of 40 nanometers changed from 0 to 8%. The above parameters can be used as a control parameter for heat transfer, fluid flow and temperature distributions. The results show that in situations where the heated circular body is close to the lower wall of the cavity, the change of temperature field and streamlines is more noticeable than any other position. On the other hand, Nusselt number and consequently heat transfer increases with increasing of solid volume fraction of nanoparticles. Also when the radius of the body decrease from 0.3L to 0.15L, the Nusselt number increase by 79.15 percent.
Journal of Modeling in Engineering
دانشگاه سمنان
2008-4854
11
v.
33
no.
2013
57
68
http://modelling.journals.semnan.ac.ir/article_1644_87ef9c5e43e80674a458949c0d3c60bb.pdf
dx.doi.org/10.22075/jme.2017.1644
EVALUATION OF EFFECT OF REACTIVE POWER CONTROL STRATEGY BASED ON VOLTAGE TERMINAL OF GENERATORS ON LIMIT INDUCED BIFURCATION AND DYNAMIC VOLTAGE STABILITY MARGIN
M.H.
Velayati
author
N.
Amjady
author
I.
Khajevandi
author
text
article
2013
per
Reactive power limit of power system generators has a significant effect on the static voltage stability margin such as maximum load ability point and dynamic voltage stability margin such as HB, LIB and SNB. However, as the load increases, reactive power demand increases as well and thus reactive power limit of generators or other voltage-regulating devices such as Static Var Compensators (SVCs) may reach. Therefore, the voltage stability margin is decreased and or voltage collapse is occurred. Hence, different techniques such as reactive power re-dispatch or change of terminal voltage of generators, use of reactive power compensation devices and optimization method to determine optimum sizing and setting of this device is proposed for improving and increasing reactive power capacity. In this paper, based on a combined method include of time domain simulation, modal analysis and bifurcation theory effect of the regulation of terminal voltage of critical generators on the reactive power limit of generators and dynamic voltage stability status of power system based on the HB and LIB is evaluated. The obtained results give good information for network operators to optimize planning and operating of the power system. The proposed dynamic method is examined on the New England 39-bus, IEEE 68-bus test systems.
Journal of Modeling in Engineering
دانشگاه سمنان
2008-4854
11
v.
33
no.
2013
69
81
http://modelling.journals.semnan.ac.ir/article_1645_8612685a9cfd9ff3196d71686cdf9b3c.pdf
dx.doi.org/10.22075/jme.2017.1645
DEVELOPING A MODEL TO PREDICT THE PULSE DURATION OF TENSILE RESPONSE AT THE BOTTOM OF ASPHALT LAYER
M.
Fakhri
author
M.
Dolatali Zadeh
author
A.
Ghanizadeh
author
text
article
2013
per
Fatigue damage is one of the most important distresses in asphalt pavements. Fatigue cracking is influenced by many factors such as pavement structure, loading and environmental conditions and the shape and duration of tensile response pulses at the bottom of asphalt layer greatly affects fatigue life of apshlat layer. In this study, both thick and thin pavement structures in different conditions were analyzed by the 3D-Move program. In the analysis, the asphalt layer was treated as viscoelastic and other layers were considered as elastic material. Haversine and bell-shape functions were fitted to the tensile response pulses computed using dynamic analysis. The results showed that the vehicle speed, thickness of asphalt pavement, pavement temperature and radius of the contact area are the most important factors that affect the shape and duration (frequency) of the tensile response pulses at the bottom of the asphalt layer. In this study, two general models are presented to predict the duration of stress and strain response pulses in longitudinal and transverse directions based on the haversine and the bell-shape waveforms.
Journal of Modeling in Engineering
دانشگاه سمنان
2008-4854
11
v.
33
no.
2013
83
98
http://modelling.journals.semnan.ac.ir/article_1646_e9cb18b490842f08c810d65a5662b337.pdf
dx.doi.org/10.22075/jme.2017.1646