Abstract: Hydrodynamic pressures acting on upstream of concrete dams during an earthquake are an important factor in designing and assessing the safety of these structures in Earthquake regions. Due to inherent complexities, assessing exact hydrodynamic pressure is only feasible for problems with simple geometry. In this research, the governing equation of concrete gravity dam reservoirs with effect of fluid viscosity in frequency domain is solved and then compared with that in which viscosity is assumed zero. The results show that viscosity influences the reservoir-s natural frequency. In excitation frequencies near the reservoir's natural frequencies, hydrodynamic pressure has a considerable difference in compare to the results of non-viscose fluid.
Abstract: To make use of the limited amounts of water in arid
region, the Iranians developed man-made underground water
channels called qanats (kanats) .In fact, qanats may be considered as
the first long-distance water transfer system. Qanats are an ancient
water transfer system found in arid regions wherein groundwater
from mountainous areas, aquifers and sometimes from rivers, was
brought to points of re-emergence such as an oasis, through one or
more underground tunnels. The tunnels, many of which were
kilometers in length, had designed for slopes to provide gravitational
flow. The tunnels allowed water to drain out to the surface by gravity
to supply water to lower and flatter agricultural land.
Qanats have been an ancient, sustainable system facilitating the
harvesting of water for centuries in Iran, and more than 35 additional
countries of the world such as India, Arabia, Egypt, North Africa,
Spain and even to New world.
There are about 22000 qanats in Iran with 274000 kilometers of
underground conduits all built by manual labor. The amount of
water of the usable qanats of Iran produce is altogether 750 to
1000 cubic meter per second. The longest chain of qanat is
situated in Gonabad region in Khorasan province. It is 70
kilometers long. Qanats are renewable water supply systems that
have sustained agricultural settlement on the Iranian plateau for
millennia. The great advantages of Qanats are no evaporation
during transit, little seepage , no raising of the water- table and no
pollution in the area surrounding the conduits. Qanat systems
have a profound influence on the lives of the water users in Iran, and
conform to Iran-s climate. Qanat allows those living in a desert
environment adjacent to a mountain watershed to create a large oasis
in an otherwise stark environment.
This paper explains qanats structure designs, their history,
objectives causing their creation, construction materials, locations
and their importance in different times, as well as their present
sustainable role in Iran.
Abstract: The copper flotation tailings from Konkola Copper
mine in Nchanga, Zambia were used in the study. The purpose of this
study was to determine the leaching characteristics of the tailings
material prior and after the physical beneficiation process is
employed. The Knelson gravity concentrator (KC-MD3) was used for
the beneficiation process. The copper leaching efficiencies and
impurity co-extraction percentages in both the upgraded and the raw
feed material were determined at different pH levels and temperature.
It was observed that the copper extraction increased with an increase
in temperature and a decrease in pH levels. In comparison to the raw
feed sample, the upgraded sample reported a maximum copper
extraction of 69% which was 9%, higher than raw feed % extractions.
The impurity carry over was reduced from 18% to 4 % on the
upgraded sample. The reduction in impurity co-extraction was as a
result of the removal of the reactive gangue elements during the
upgrading process, this minimized the number of side reaction
occurring during leaching.
Abstract: In the paper, the energetic features of the loaded gait
are newly analyzed depending on the trunk flexion change. To
investigate the loaded gait, walking experiments are performed for five
subjects and, the ground reaction forces and kinematic data are
measured. Based on these information, we compute the impulse,
momentum and mechanical works done on the center of body mass,
through the trunk flexion change. As a result, it is shown that the trunk
flexion change does not affect the impulses and momentums during
the step-to-step transition as well. However, the direction of the
pre-collision momentum does change depending on the trunk flexion
change, which is degenerated just after (or during) the collision period.
Abstract: The mathematical framework for studying of a fuzzy approximate reasoning is presented in this paper. Two important defuzzification methods (Area defuzzification and Height defuzzification) besides the center of gravity method which is the best well known defuzzification method are described. The continuity of the defuzzification methods and its application to a fuzzy feedback control are discussed.
Abstract: Shear walls are used in most of the tall buildings for
carrying the lateral load. When openings for doors or windows are
necessary to be existed in the shear walls, a special type of the shear
walls is used called "coupled shear walls" which in some cases is
stiffened by specific beams and so, called "stiffened coupled shear
walls".
In this paper, a mathematical method for geometrically nonlinear
analysis of the stiffened coupled shear walls has been presented.
Then, a suitable formulation for determining the critical load of the
stiffened coupled shear walls under gravity force has been proposed.
The governing differential equations for equilibrium and deformation
of the stiffened coupled shear walls have been obtained by setting up
the equilibrium equations and the moment-curvature relationships for
each wall. Because of the complexity of the differential equation, the
energy method has been adopted for approximate solution of the
equations.
Abstract: A new Meta heuristic approach called "Randomized gravitational emulation search algorithm (RGES)" for solving vertex covering problems has been designed. This algorithm is found upon introducing randomization concept along with the two of the four primary parameters -velocity- and -gravity- in physics. A new heuristic operator is introduced in the domain of RGES to maintain feasibility specifically for the vertex covering problem to yield best solutions. The performance of this algorithm has been evaluated on a large set of benchmark problems from OR-library. Computational results showed that the randomized gravitational emulation search algorithm - based heuristic is capable of producing high quality solutions. The performance of this heuristic when compared with other existing heuristic algorithms is found to be excellent in terms of solution quality.
Abstract: The effect of time-periodic oscillations of the Rayleigh- Benard system on the heat transport in dielectric liquids is investigated by weakly nonlinear analysis. We focus on stationary convection using the slow time scale and arrive at the real Ginzburg- Landau equation. Classical fourth order Runge-kutta method is used to solve the Ginzburg-Landau equation which gives the amplitude of convection and this helps in quantifying the heat transfer in dielectric liquids in terms of the Nusselt number. The effect of electrical Rayleigh number and the amplitude of modulation on heat transport is studied.
Abstract: Nonlinear propagation of ion-acoustic waves in a selfgravitating
dusty plasma consisting of warm positive ions,
isothermal two-temperature electrons and negatively charged dust
particles having charge fluctuations is studied using the reductive
perturbation method. It is shown that the nonlinear propagation of
ion-acoustic waves in such plasma can be described by an uncoupled
third order partial differential equation which is a modified form of
the usual Korteweg-deVries (KdV) equation. From this nonlinear
equation, a new type of solution for the ion-acoustic wave is
obtained. The effects of two-temperature electrons, gravity and dust
charge fluctuations on the ion-acoustic solitary waves are discussed
with possible applications.
Abstract: The main objective developed in this paper is to find a
graphic technique for modeling, simulation and diagnosis of the
industrial systems. This importance is much apparent when it is about
a complex system such as the nuclear reactor with pressurized water
of several form with various several non-linearity and time scales. In
this case the analytical approach is heavy and does not give a fast
idea on the evolution of the system. The tool Bond Graph enabled us
to transform the analytical model into graphic model and the
software of simulation SYMBOLS 2000 specific to the Bond Graphs
made it possible to validate and have the results given by the
technical specifications. We introduce the analysis of the problem
involved in the faults localization and identification in the complex
industrial processes. We propose a method of fault detection applied
to the diagnosis and to determine the gravity of a detected fault. We
show the possibilities of application of the new diagnosis approaches
to the complex system control. The industrial systems became
increasingly complex with the faults diagnosis procedures in the
physical systems prove to become very complex as soon as the
systems considered are not elementary any more. Indeed, in front of
this complexity, we chose to make recourse to Fault Detection and
Isolation method (FDI) by the analysis of the problem of its control
and to conceive a reliable system of diagnosis making it possible to
apprehend the complex dynamic systems spatially distributed applied
to the standard pressurized water nuclear reactor.
Abstract: Future space vehicles will require the use of non-toxic, cryogenic propellants, because of the performance advantages over the toxic hypergolic propellants and also because of the environmental and handling concerns. A prototypical capillary flow liquid acquisition device (LAD) for cryogenic propellants was fabricated with a mesh screen, covering a rectangular flow channel with a cylindrical outlet tube, and was tested with liquid oxygen (LOX). In order to better understand the performance in various gravity environments and orientations with different submersion depths of the LAD, a series of computational fluid dynamics (CFD) simulations of LOX flow through the LAD screen channel, including horizontally and vertically submersions of the LAD channel assembly at normal gravity environment was conducted. Gravity effects on the flow field in LAD channel are inspected and analyzed through comparing the simulations.
Abstract: In order to alleviate the mental and physical problems
of persons with disabilities, animal-assisted therapy (AAT) is one of
the possible modalities that employs the merit of the human-animal
interaction. Nevertheless, to achieve the purpose of AAT for persons
with severe disabilities (e.g. spinal cord injury, stroke, and
amyotrophic lateral sclerosis), real-time animal language
interpretation is desirable. Since canine behaviors can be visually
notable from its tail, this paper proposes the automatic real-time
interpretation of canine tail language for human-canine interaction in
the case of persons with severe disabilities. Canine tail language is
captured via two 3-axis accelerometers. Directions and frequencies
are selected as our features of interests. The novel fuzzy rules based
on Gaussian-Trapezoidal model and center of gravity (COG)-based
defuzzification method are proposed in order to interpret the features
into four canine emotional behaviors, i.e., agitate, happy, scare and
neutral as well as its blended emotional behaviors. The emotional
behavior model is performed in the simulated dog and has also been
evaluated in the real dog with the perfect recognition rate.
Abstract: As it is known, buoyancy and drag forces rule bubble's rise velocity in a liquid column. These forces are strongly dependent on fluid properties, gravity as well as equivalent's diameter. This study reports a set of bubble rising velocity experiments in a liquid column using water or glycerol. Several records of terminal velocity were obtained. The results show that bubble's rise terminal velocity is strongly dependent on dynamic viscosity effect. The data set allowed to have some terminal velocities data interval of 8.0 ? 32.9 cm/s with Reynolds number interval 1.3 -7490. The bubble's movement was recorded with a video camera. The main goal is to present an original set data and results that will be discussed based on two-phase flow's theory. It will also discussed, the prediction of terminal velocity of a single bubble in liquid, as well as the range of its applicability. In conclusion, this study presents general expressions for the determination of the terminal velocity of isolated gas bubbles of a Reynolds number range, when the fluid proprieties are known.
Abstract: The dispersion of heavy particles line in an isotropic
and incompressible three-dimensional turbulent flow has been
studied using the Kinematic Simulation techniques to find out the
evolution of the line fractal dimension. In this study, the fractal
dimension of the line is found for different cases of heavy particles
inertia (different Stokes numbers) in the absence of the particle
gravity with a comparison with the fractal dimension obtained in the
diffusion case of material line at the same Reynolds number. It can
be concluded for the dispersion of heavy particles line in turbulent
flow that the particle inertia affect the fractal dimension of a line
released in a turbulent flow for Stokes numbers 0.02 < St < 2. At the
beginning for small times, most of the different cases are not affected
by the inertia until a certain time, the particle response time τa, with
larger time as the particles inertia increases, the fractal dimension of
the line increases owing to the particles becoming more sensitive to
the small scales which cause the change in the line shape during its
journey.
Abstract: The present study investigates numerically the
phenomenon of vortex-shedding and its suppression in twodimensional
mixed convective flow past a square cylinder under the
joint influence of buoyancy and free-stream orientation with respect
to gravity. The numerical experiments have been conducted at a
fixed Reynolds number (Re) of 100 and Prandtl number (Pr) of 0.71,
while Richardson number (Ri) is varied from 0 to 1.6 and freestream
orientation, α, is kept in the range 0o≤ α ≤ 90o, with 0o
corresponding to an upward flow and 90o representing a cross-flow
scenario, respectively. The continuity, momentum and energy
equations, subject to Boussinesq approximation, are discretized using
a finite difference method and are solved by a semi-explicit pressure
correction scheme. The critical Richardson number, leading to the
suppression of the vortex-shedding (Ric), is estimated by using
Stuart-Landau theory at various free-stream orientations and the
neutral curve is obtained in the Ri-α plane. The neutral curve
exhibits an interesting non-monotonic behavior with Ric first
increasing with increasing values of α upto 45o and then decreasing
till 70o. Beyond 70o, the neutral curve again exhibits a sharp
increasing asymptotic trend with Ric approaching very large values
as α approaches 90o. The suppression of vortex shedding is not
observed at α = 90o (cross-flow). In the unsteady flow regime, the
Strouhal number (St) increases with the increase in Richardson
number.
Abstract: In the present study, the lattice Boltzmann Method (LBM) is applied for simulating of Natural Convection in an inclined open ended cavity. The cavity horizontal walls are insulated while the west wall is maintained at a uniform temperature higher than the ambient. Prandtl number is fixed to 0.71 (air) while Rayligh numbers, aspect ratio of the cavity are changed in the range of 103 to 104 and of 1-4, respectively. The numerical code is validated for the previously results for open ended cavities, and then the results of an inclined open ended cavity for various angles of rotating open ended cavity are presented. Result shows by increasing of aspect ratio, the average Nusselt number on hot wall decreases for all rotation angles. When gravity acceleration direction is opposite of standard gravity direction the convection heat transfer has a manner same as conduction.
Abstract: The fine structure of supercavitation in the wake of a
symmetrical cylinder is studied with high-speed video cameras. The
flow is observed in a cavitation tunnel at the speed of 8m/sec when the
sidewall and the wake are partially filled with the massive cavitation
bubbles. The present experiment observed that a two-dimensional
ripple wave with a wave length of 0.3mm is propagated in a
downstream direction, and then abruptly increases to a thicker
three-dimensional layer. IR-photography recorded that the wakes
originated from the horseshoe vortexes alongside the cylinder. The
wake was developed to inside the dead water zone, which absorbed the
bubbly wake propelled from the separated vortices at the center of the
cylinder. A remote sensing classification technique (maximum most
likelihood) determined that the surface porosity was 0.2, and the mean
speed in the mixed wake was 7m/sec. To confirm the existence of
two-dimensional wave motions in the interface, the experiments were
conducted at a very low frequency, and showed similar gravity waves
in both the upper and lower interfaces.
Abstract: The purpose of this study is to find natural gait of
biped robot such as human being by analyzing the COG (Center Of
Gravity) trajectory of human being's gait. It is discovered that human
beings gait naturally maintain the stability and use the minimum
energy. This paper intends to find the natural gait pattern of biped
robot using the minimum energy as well as maintaining the stability by
analyzing the human's gait pattern that is measured from gait image on
the sagittal plane and COG trajectory on the frontal plane. It is not
possible to apply the torques of human's articulation to those of biped
robot's because they have different degrees of freedom. Nonetheless,
human and 5-link biped robots are similar in kinematics. For this, we
generate gait pattern of the 5-link biped robot by using the GA
algorithm of adaptation gait pattern which utilize the human's ZMP
(Zero Moment Point) and torque of all articulation that are measured
from human's gait pattern. The algorithm proposed creates biped
robot's fluent gait pattern as that of human being's and to minimize
energy consumption because the gait pattern of the 5-link biped robot
model is modeled after consideration about the torque of human's each
articulation on the sagittal plane and ZMP trajectory on the frontal
plane. This paper demonstrate that the algorithm proposed is superior
by evaluating 2 kinds of the 5-link biped robot applied to each gait
patterns generated both in the general way using inverse kinematics
and in the special way in which by considering visuality and
efficiency.
Abstract: Small satellites have become increasingly popular recently as a means of providing educational institutes with the chance to design, construct, and test their spacecraft from beginning to the possible launch due to the low launching cost. This approach is remarkably cost saving because of the weight and size reduction of such satellites. Weight reduction could be realised by utilising electromagnetic coils solely, instead of different types of actuators. This paper describes the restrictions of using only “Electromagnetic" actuation for 3D stabilisation and how to make the magnetorquer based attitude control feasible using Fuzzy Logic Control (FLC). The design is developed to stabilize the spacecraft against gravity gradient disturbances with a three-axis stabilizing capability.
Abstract: Minor law breaking seems more and more to be a part
of adolescence behavior. An important risk factor which seems to
influence delinquency appears to be the socio-economic one.
According to Romanian statistics, during the first six months of 2012,
1,378 minors have committed various crimes, the most common
being theft, sexual offenses and violent assaults. Drug-related
offenses did not reach the gravity of those from high income
countries of the European Union, but have a continuous upward
during the last years.
The aim of our research was to examine whether delinquency in
adolescence is correlated to mental disorders or socio-economic and
familial factors. Forensic psychiatric expertise was performed to 79
adolescents who committed offenses between 01 January 2012 and
31 December 2012. Teenagers, with ages between 12 and 17, were
examined by day hospitalization in the University Clinic of
Psychiatry Craiova.