Abstract: In this study, an analysis has been performed for
heat and mass transfer of a steady laminar boundary-layer flow
of a viscous flow past a nonlinearly stretching sheet.
Parameters n, Ec, k0, Sc represent the dominance of the
nonlinearly effect, viscous effect, radiation effect and mass
transfer effect which have presented in governing equations,
respectively. The similarity transformation and the
finite-difference method have been used to analyze the present
problem.
Abstract: This paper proposes a method to vibration analysis in
order to on-line monitoring and predictive maintenance during the
milling process. Adapting envelope method to diagnostics and the
analysis for milling tool materials is an important contribution to the
qualitative and quantitative characterization of milling capacity and a
step by modeling the three-dimensional cutting process. An
experimental protocol was designed and developed for the
acquisition, processing and analyzing three-dimensional signal. The
vibration envelope analysis is proposed to detect the cutting capacity
of the tool with the optimization application of cutting parameters.
The research is focused on Hilbert transform optimization to evaluate
the dynamic behavior of the machine/ tool/workpiece.
Abstract: For maintenance of a spine stability during the
postoperative period a transpedicular fixing of its elements is often
used. Usually the transpedicular systems are formed of rods which as
a result form a design of the frame type, fastening by screws to
vertebras. Such design should be rigid and perceive loadings
operating from the spine without essential deformations. From the
perfection point of view of known designs their stress
whole, and each of elements, in particular is of interest. In this study
the modeling of the transpedicular screw is performed and
estimation of its deformations taking into account interaction with a
vertebra body having variable structure is made.
Abstract: A transient heat transfer mathematical model for the
prediction of temperature distribution in the car body during primer
baking has been developed by considering the thermal radiation and
convection in the furnace chamber and transient heat conduction
governing equations in the car framework. The car cockpit is
considered like a structure with six flat plates, four vertical plates
representing the car doors and the rear and front panels. The other
two flat plates are the car roof and floor. The transient heat
conduction in each flat plate is modeled by the lumped capacitance
method. Comparison with the experimental data shows that the heat
transfer model works well for the prediction of thermal behavior of
the car body in the curing furnace, with deviations below 5%.
Abstract: This paper investigates the effect of replacing
crankshaft with cam on the indicated torque during compression and
power strokes in internal combustion engines. A Cycloidal cam
profile was used in Revetec engine to calculate and compare the
torque to a conventional engine, using a computational method.
Firstly, the cylinder pressure was calculated using Ferguson equation,
and then the torque calculated depending on cylinder pressure values
in every crank angle. the results showed that by using Cycloidal cam
profile in Revetec engine the torque can increased by 14% compared
with conventional engines, which means an increase in engine
efficiency.
Abstract: Cavitation, usually known as a destructive
phenomenon, involves turbulent unsteady two-phase flow. Having
such features, cavitating flows have been turned to a challenging
topic in numerical studies and many researches are being done for
better understanding of bubbly flows and proposing solutions to
reduce its consequent destructive effects. Aeration may be regarded
as an effective protection against cavitation erosion in many
hydraulic structures, like gated tunnels. The paper concerns
numerical simulation of flow in discharge gated tunnel of a dam
using ing RNG k -ε model coupled with the volume of fluid (VOF)
method and the zone which is susceptible of cavitation inception in
the tunnel is predicted. In the second step, a vent is considered in the
mentioned zone for aeration and the numerical simulation is done
again to study the effects of aeration. The results show that aeration
is an impressively useful method to exclude cavitation in mentioned
tunnels.
Abstract: One of the most important parts of a cement factory is
the cement rotary kiln which plays a key role in quality and quantity of produced cement. In this part, the physical exertion and bilateral
movement of air and materials, together with chemical reactions take
place. Thus, this system has immensely complex and nonlinear dynamic equations. These equations have not worked out yet. Only
in exceptional case; however, a large number of the involved parameter were crossed out and an approximation model was
presented instead. This issue caused many problems for designing a
cement rotary kiln controller. In this paper, we presented nonlinear predictor and simulator models for a real cement rotary kiln by using
nonlinear identification technique on the Locally Linear Neuro-
Fuzzy (LLNF) model. For the first time, a simulator model as well as
a predictor one with a precise fifteen minute prediction horizon for a
cement rotary kiln is presented. These models are trained by
LOLIMOT algorithm which is an incremental tree-structure
algorithm. At the end, the characteristics of these models are expressed. Furthermore, we presented the pros and cons of these
models. The data collected from White Saveh Cement Company is used for modeling.
Abstract: This work is focused on the numerical prediction of the fracture resistance of a flat stiffened panel made of the aluminium alloy 2024 T3 under a monotonic traction condition. The performed numerical simulations have been based on the micromechanical Gurson-Tvergaard (GT) model for ductile damage. The applicability of the GT model to this kind of structural problems has been studied and assessed by comparing numerical results, obtained by using the WARP 3D finite element code, with experimental data available in literature. In the sequel a home-made procedure is presented, which aims to increase the residual strength of a cracked stiffened aluminum panel and which is based on the stochastic design improvement (SDI) technique; a whole application example is then given to illustrate the said technique.
Abstract: An experimental investigation was performed on pulp
liquid flow in straight ducts with a square cross section. Fully
developed steady flow was visualized and the fiber concentration was
obtained using a light-section method developed by the author et al.
The obtained results reveal quantitatively, in a definite form, the
distribution of the fiber concentration. From the results and
measurements of pressure loss, it is found that the flow characteristics
of pulp liquid in ducts can be classified into five patterns. The
relationships among the distributions of mean and fluctuation of fiber
concentration, the pressure loss and the flow velocity are discussed,
and then the features for each pattern are extracted. The degree of
nonuniformity of the fiber concentration, which is indicated by the
standard deviation of its distribution, is decreased from 0.3 to 0.05
with an increase in the velocity of the tested pulp liquid from 0.4 to
0.8%.
Abstract: In this study the elastic-plastic stress distribution in
weld-bonded joint, fabricated from austenitic stainless steel (AISI
304) sheet of 1.00 mm thickness and Epoxy adhesive Araldite 2011,
subjected to axial loading is investigated. This is needed to improve
design procedures and welding codes, and saving efforts in the
cumbersome experiments and analysis. Therefore, a complete 3-D
finite element modelling and analysis of spot welded, bonded and
weld-bonded joints under axial loading conditions is carried out. A
comprehensive systematic experimental program is conducted to
determine many properties and quantities, of the base metals and the
adhesive, needed for FE modelling, such like the elastic – plastic
properties, modulus of elasticity, fracture limit, the nugget and heat
affected zones (HAZ) properties, etc. Consequently, the finite
element models developed, for each case, are used to evaluate
stresses distributions across the entire joint, in both the elastic and
plastic regions. The stress distribution curves are obtained,
particularly in the elastic regions and found to be consistent and in
excellent agreement with the published data. Furthermore, the
stresses distributions are obtained in the weld-bonded joint and
display the best results with almost uniform smooth distribution
compared to spot and bonded cases. The stress concentration peaks at
the edges of the weld-bonded region, are almost eliminated resulting
in achieving the strongest joint of all processes.
Abstract: This work deals with the design of the robotic assembly
system for the roller clamps. The task is characterized by high speed,
high yield and safety engagement. This paper describes the design of
different parts of an automated high speed machine to assemble the
parts of roller clamps. The roller clamp robotic assembly system
performs various processes in the assembly line which include clamp
body and roller feeding, inserting the roller into the clamp body, and
dividing the rejected clamp and successfully assembled clamp into
their own tray. The electrical/electronics design of the machine is
discussed. The target is to design a cost effective, minimum
maintenance and high speed machine for the industry applications.
Abstract: This paper addresses linear quadratic regulation (LQR)
for variable speed variable pitch wind turbines. Because of the
inherent nonlinearity of wind turbine, a set of operating conditions is
identified and then a LQR controller is designed for each operating
point. The feedback controller gains are then interpolated linearly to
get control law for the entire operating region. Besides, the
aerodynamic torque and effective wind speed are estimated online to
get the gain-scheduling variable for implementing the controller. The
potential of the method is verified through simulation with the help of
MATLAB/Simulink and GH Bladed. The performance and
mechanical load when using LQR are also compared with that when
using PI controller.
Abstract: In inspection and workpiece localization, sampling point data is an important issue. Since the devices for sampling only sample discrete points, not the completely surface, sampling size and location of the points will be taken into consideration. In this paper a method is presented for determining the sampled points size and location for achieving efficient sampling. Firstly, uncertainty analysis of the localization parameters is investigated. A localization uncertainty model is developed to predict the uncertainty of the localization process. Using this model the minimum size of the sampled points is predicted. Secondly, based on the algebra theory an eigenvalue-optimal optimization is proposed. Then a freeform surface is used in the simulation. The proposed optimization is implemented. The simulation result shows its effectivity.
Abstract: In this paper, an analytical approach for free vibration
analysis of rectangular and circular membranes is presented. The
method is based on wave approach. From wave standpoint vibration
propagate, reflect and transmit in a structure. Firstly, the propagation
and reflection matrices for rectangular and circular membranes are
derived. Then, these matrices are combined to provide a concise and
systematic approach to free vibration analysis of membranes.
Subsequently, the eigenvalue problem for free vibration of membrane
is formulated and the equation of membrane natural frequencies is
constructed. Finally, the effectiveness of the approach is shown by
comparison of the results with existing classical solution.
Abstract: This paper introduces a high-gain observer based state of charge(SOC) estimator for lithium-Ion batteries. The proposed SOC estimator has a high-gain observer(HGO) structure. The HGO scheme enhances the transient response speed and diminishes the effect of uncertainties. Furthermore, it guarantees that the output feedback controller recovers the performance of the state feedback controller when the observer gain is sufficiently high. In order to show the effectiveness of the proposed method, the linear RC battery model in ADVISOR is used. The performance of the proposed method is compared with that of the conventional linear observer(CLO) and some simulation result is given.
Abstract: Rotational Smart Lighting Control System can supply
the quantity of lighting which is required to run plants by rotating few
LED and Fluorescent instead of that are used in the existing plant
factories.The initial installation of the existing plants factory is
expensive, so in order to solve the problem with smart lighting control
system was developed.
The beam required intensity for the growth of crops, Photosynthetic
Photon Flux Density(PPFD)is calculated; and the number of LED, are
installed on the blades, set; using the Lighting Simulation
Program.Relux, it is able to confirm that the difference of the beam
intensity between the center and the outer of lighting system when the
lighting device is rotating.
Abstract: Heat transfer from two cam shape cylinder in tandem
arrangement had been studied numerically.
The distance between the centers of cylinders (L) is allowed to
vary to change the longitudinal pitch ratio (L/Deq). The equivalent
diameter of the cylinder (Deq) is 27.6 mm and longitudinal pitch ratio
varies in range 2
Abstract: In this paper, a theoretical formula is presented to
predict the instantaneous folding force of the first fold creation in a
square column under axial loading. Calculations are based on analysis
of “Basic Folding Mechanism" introduced by Wierzbicki and
Abramowicz. For this purpose, the sum of dissipated energy rate under
bending around horizontal and inclined hinge lines and dissipated
energy rate under extensional deformations are equated to the work rate
of the external force on the structure. Final formula obtained in this
research, reasonably predicts the instantaneous folding force of the first
fold creation versus folding distance and folding angle and also predicts
the instantaneous folding force instead of the average value. Finally,
according to the calculated theoretical relation, instantaneous folding
force of the first fold creation in a square column was sketched
versus folding distance and was compared to the experimental results
which showed a good correlation.
Abstract: Experiments have been performed to investigate the radiation effects on mixed convection heat transfer for thermally developing airflow in vertical ducts with two differentially heated isothermal walls and two adiabatic walls. The investigation covers the Reynolds number Re = 800 to Re = 2900, heat flux varied from 256 W/m2 to 863 W/m2, hot wall temperature ranges from 27°C to 100 °C, aspect ratios 1 & 0.5 and the emissivity of internal walls are 0.05 and 0.85. In the present study, combined flow visualization was conducted to observe the flow patterns. The effect of surface temperature along the walls was studied to investigate the local Nusselt number variation within the duct. The result shows that flow condition and radiation significantly affect the total Nusselt number and tends to reduce the buoyancy condition.
Abstract: Omni directional mobile robots have been popularly
employed in several applications especially in soccer player robots
considered in Robocup competitions. However, Omni directional
navigation system, Omni-vision system and solenoid kicking
mechanism in such mobile robots have not ever been combined. This
situation brings the idea of a robot with no head direction into
existence, a comprehensive Omni directional mobile robot. Such a
robot can respond more quickly and it would be capable for more
sophisticated behaviors with multi-sensor data fusion algorithm for
global localization base on the data fusion. This paper has tried to
focus on the research improvements in the mechanical, electrical and
software design of the robots of team ADRO Iran. The main
improvements are the world model, the new strategy framework,
mechanical structure, Omni-vision sensor for object detection, robot
path planning, active ball handling mechanism and the new kicker
design, , and other subjects related to mobile robot