Abstract: This paper aims to present the design, fabrication and test of a novel piezoelectric actuated, check-valves embedded micropump having the advantages of miniature size, light weight and low power consumption. This device is designed to pump gases and liquids with the capability of performing the self-priming and bubble-tolerant work mode by maximizing the stroke volume of the membrane as well as the compression ratio via minimization of the dead volume of the micropump chamber and channel. By experiment apparatus setup, we can get the real-time values of the flow rate of micropump, the displacement of the piezoelectric actuator and the deformation of the check valve, simultaneously. The micropump with check valve 0.4 mm in thickness obtained higher output performance under the sinusoidal waveform of 120 Vpp. The micropump achieved the maximum pumping rates of 42.2 ml/min and back pressure of 14.0 kPa at the corresponding frequency of 28 and 20 Hz. The presented micropump is able to pump gases with a pumping rate of 196 ml/min at operating frequencies of 280 Hz under the sinusoidal waveform of 120 Vpp.
Abstract: Schools today face ever-increasing demands in their attempts to ensure that students are well equipped to enter the workforce and navigate a complex world. Research indicates that computer technology can help support learning, implementation of various experiments or learning games, and that it is especially useful in developing the higher-order skills of critical thinking, observation, comprehension, implementation, comparison, analysis and active attention to activities such as research, field work, simulations and scientific inquiry. The ICT in education supports the learning procedure by enabling it to be more flexible and effective, create a rich and attractive training environment and equip the students with knowledge and potential useful for the competitive social environment in which they live. This paper presents the design, the development, and the results of the evaluation analysis of an interactive educational game which using real electric vehicles - toys (material) on a toy race track. When the game starts each student selects a specific vehicle toy. Then students are answering questionnaires in the computer. The vehicles' speed is related to the percentage of right answers in a multiple choice questionnaire (software). Every question has its own significant value depending of the different level of questionnaire. Via the developed software, each right or wrong answers in questionnaire increase or decrease the real time speed of their vehicle toys. Moreover the rate of vehicle's speed increase or decrease depends on the difficulty level of each question. The aim of the work is to attract the student’s interest in a learning process and also to improve their scores. The developed real time game was tested using independent populations of students of age groups: 8-10, 11-14, 15-18 years. Standard educational and statistical analysis tools were used for the evaluation analysis of the game. Results reveal that students using the developed real time control game scored much higher (60%) than students using a traditional simulation game on the same questionnaire. Results further indicate that student's interest in repeating the developed real time control gaming was far higher (70%) than the interest of students using a traditional simulation game.
Abstract: In order to better understand the performance of
screen channel liquid acquisition devices (LADs) in liquid oxygen (LOX), a computational fluid dynamics (CFD) simulation of LOX passing through a LAD screen channel was conducted. In the
simulation, the screen is taken as a 'porous jump' where the pressure
drop across the screen depends on the incoming velocity and is formulated by Δp = Av + Bv2
. The CFD simulation reveals the importance of the pressure losses due to the flow entering from
across the screen and impacting and merging with the channel flow
and the vortices in the channel to the cumulative flow resistance. In fact, both the flow resistance of flows impact and mergence and the
resistance created by vortices are much larger than the friction and dynamic pressure losses in the channel and are comparable to the
flow resistance across the screen. Therefore, these resistances in the
channel must be considered as part of the evaluation for the LAD
channel performance. For proper operation of a LAD in LOX these resistances must be less than the bubble point pressure for the screen
channel in LOX. The simulation also presents the pressure and velocity distributions within the LAD screen channel, expanding the understanding of the fluid flow characteristics within the channel.
Abstract: Strict stability can present the rate of decay of the
solution, so more and more investigators are beginning to study the
topic and some results have been obtained. However, there are few
results about strict stability of stochastic differential equations. In
this paper, using Lyapunov functions and Razumikhin technique, we
have gotten some criteria for the strict stability of impulsive stochastic
functional differential equations with markovian switching.
Abstract: The migration of a deformable drop in simple shear
flow at finite Reynolds numbers is investigated numerically by
solving the full Navier-Stokes equations using a finite
difference/front tracking method. The objectives of this study are to
examine the effectiveness of the present approach to predict the
migration of a drop in a shear flow and to investigate the behavior of
the drop migration with different drop sizes and non-unity viscosity
ratios. It is shown that the drop deformation depends strongly on the
capillary number, so that; the proper non-dimensional number for the
interfacial tension is the capillary number. The rate of migration
increased with increasing the drop radius. In other words, the
required time for drop migration to the centreline decreases. As the
viscosity ratio increases, the drop rotates more slowly and the
lubrication force becomes stronger. The increased lubrication force
makes it easier for the drop to migrate to the centre of the channel.
The migration velocity of the drop vanishes as the drop reaches the
centreline under viscosity ratio of one and non-unity viscosity ratios.
To validate the present calculations, some typical results are
compared with available experimental and theoretical data.
Abstract: This paper discusses a new heavy tailed distribution based data hiding into discrete cosine transform (DCT) coefficients of image, which provides statistical security as well as robustness against steganalysis attacks. Unlike other data hiding algorithms, the proposed technique does not introduce much effect in the stegoimage-s DCT coefficient probability plots, thus making the presence of hidden data statistically undetectable. In addition the proposed method does not compromise on hiding capacity. When compared to the generic block DCT based data-hiding scheme, our method found more robust against a variety of image manipulating attacks such as filtering, blurring, JPEG compression etc.
Abstract: This paper presents a comparative study on dry and wet grinding through experimental investigation in the grinding of CSM glass fibre reinforced polymer laminates using a pink aluminium oxide wheel. Different sets of experiments were performed to study the effects of the independent grinding parameters such as grinding wheel speed, feed and depth of cut on dependent performance criteria such as cutting forces and surface finish. Experimental conditions were laid out using design of experiment central composite design. An effective coolant was sought in this study to minimise cutting forces and surface roughness for GFRP laminates grinding. Test results showed that the use of coolants reduces surface roughness, although not necessarily the cutting forces. These research findings provide useful economic machining solution in terms of optimized grinding conditions for grinding CSM GFRP.
Abstract: Ants are fascinating creatures that demonstrate the
ability to find food and bring it back to their nest. Their ability as a
colony, to find paths to food sources has inspired the development of
algorithms known as Ant Colony Systems (ACS). The principle of
cooperation forms the backbone of such algorithms, commonly used
to find solutions to problems such as the Traveling Salesman
Problem (TSP). Ants communicate to each other through chemical
substances called pheromones. Modeling individual ants- ability to
manipulate this substance can help an ACS find the best solution.
This paper introduces a Dynamic Ant Colony System with threelevel
updates (DACS3) that enhance an existing ACS. Experiments
were conducted to observe single ant behavior in a colony of
Malaysian House Red Ants. Such behavior was incorporated into the
DACS3 algorithm. We benchmark the performance of DACS3 versus
DACS on TSP instances ranging from 14 to 100 cities. The result
shows that the DACS3 algorithm can achieve shorter distance in
most cases and also performs considerably faster than DACS.
Abstract: In this paper, self-starting block hybrid method of
order (5,5,5,5)T is proposed for the solution of the special second
order ordinary differential equations with associated initial or
boundary conditions. The continuous hybrid formulations enable us
to differentiate and evaluate at some grids and off – grid points to
obtain four discrete schemes, which were used in block form for
parallel or sequential solutions of the problems. The computational
burden and computer time wastage involved in the usual reduction of
second order problem into system of first order equations are avoided
by this approach. Furthermore, a stability analysis and efficiency of
the block method are tested on stiff ordinary differential equations,
and the results obtained compared favorably with the exact solution.
Abstract: Paleoclimate was reconstructed by the clay mineral
assemblages of shale units of Pabdeh (Paleocene- Oligocene), Gurpi
(Upper Cretaceous), Kazhdumi (Albian-Cenomanian) and Gadvan
(Aptian-Neocomian) formations in the Bangestan anticline. To
compare with clay minerals assemblages in these formations,
selected samples also taken from available formations in drilled wells
in Ahvaz, Marun, Karanj, and Parsi oil fields. Collected samples
prepared using standard clay mineral methodology. They were
treated as normal, glycolated and heated oriented glass slides. Their
identification was made on X-Ray diffractographs. Illite % varies
from 8 to 36. Illite quantity increased from Pabdeh to Gurpi
Formation. This may be due to dominant dry climate. Kaolinite is in
range of 12-49%. Its variation style in different formations could be a
marker of climate changes from wet to dry which is supported by the
lithological changes. Chlorite (4-28%) can also be detected in those
samples without any kaolinite. Mixed layer minerals as the mixture
of illite-chlorite and illite-vermiculite-montmorillonite are varied
from 6 to 36%, decreased during Kazhdumi deposition from the base
to the top. This result may be according to decreasing of illite
leaching process. Vermiculite was also determined in very less
quantity and found in those units without kaolinite. Montmorillonite
varies from 8 to 43%, and its presence is due to terrestrial
depositional condition. Stratigraphical documents is also supported
this idea that clay mineral distribution is a function of the climate
changes. It seems, thus, the present results can be indicated a possible
procedure for ancient climate changes evaluation.
Abstract: The performance of ground to deep space optical
communication systems is degraded by distortion of the beam as it
propagates through the turbulent atmosphere. Turbulence causes
fluctuations in the intensity of the received signal which ultimately
affects the acquisition time required to acquire and locate the spaceborne
target using narrow laser beam. In this paper, performance of
free-space optical (FSO) communication system in atmospheric
turbulence has been analyzed in terms of acquisition time for
coherent and non-coherent modulation schemes. Numerical results
presented in graphical and tabular forms show that the acquisition
time increases with the increase in turbulence level. This is true for
both schemes. The BPSK has lowest acquisition time among all
schemes. In non-coherent schemes, M-PPM performs better than the
other schemes. With the increase in M, acquisition time becomes
lower, but at the cost of increase in system complexity.
Abstract: Dissolved gas analysis has been accepted as a sensitive, informative and reliable technique for incipient faults detection in power transformers and is widely used. In the last few years this method, which has been recommended by IEEE Power & Energy society, has been applied for fault detection in load tap changers. Regarding the critical role of load tap changers in electrical network and essential of catastrophic failures prevention, it is necessary to choose "condition based preventative maintenance strategy" which leads to reduction in costs, the number of unnecessary visits as well as the probability of interruptions and also increment in equipment reliability. In current work, considering the condition based preventative maintenance strategy, condition assessment of an Elin tap changer was carried out using dissolved gas analysis.
Abstract: In Egypt, the concept of Asset Management (AM) is
new; however, the need for applying it has become crucial because
deteriorating or losing an asset is unaffordable in a developing
country like Egypt. Therefore the current study focuses on
educational buildings as one of the most important assets regarding
planning, building, operating and maintenance expenditures. The
main objective of this study is to develop a SAMF for educational
buildings in Egypt. The General Authority for Educational Buildings
(GAEB) was chosen as a case study of the current research as it
represents the biggest governmental organization responsible for
planning, operating and maintaining schools in Egypt. To achieve the
research objective, structured interviews were conducted with senior
managers of GAEB using a pre designed questionnaire to explore the
current practice of AM. Gab analysis technique was applied against
best practices compounded from a vast literature review to identify
gaps between current practices and the desired one. The previous
steps mainly revealed; limited knowledge about strategic asset
management, no clear goals, no training, no real risk plan and lack of
data, technical and financial resources. Based on the findings, a
SAMF for GAEB was introduced and Framework implementation
steps and assessment techniques were explained in detail.
Abstract: Finding suitable non-supersingular elliptic curves for
pairing-based cryptosystems becomes an important issue for the
modern public-key cryptography after the proposition of id-based
encryption scheme and short signature scheme. In previous work
different algorithms have been proposed for finding such elliptic
curves when embedding degree k ∈ {3, 4, 6} and cofactor h ∈ {1, 2, 3,
4, 5}. In this paper a new method is presented to find more
non-supersingular elliptic curves for pairing-based cryptosystems with
general embedding degree k and large values of cofactor h. In
addition, some effective parameters of these non-supersingular elliptic
curves are provided in this paper.
Abstract: Turbulence of the incoming wind field is of paramount
importance to the dynamic response of civil engineering structures. Hence reliable stochastic models of the turbulence should be available from which time series can be generated for dynamic response and
structural safety analysis. In the paper an empirical cross spectral
density function for the along-wind turbulence component over the wind field area is taken as the starting point. The spectrum is spatially
discretized in terms of a Hermitian cross-spectral density matrix for the turbulence state vector which turns out not to be positive
definite. Since the succeeding state space and ARMA modelling of
the turbulence rely on the positive definiteness of the cross-spectral
density matrix, the problem with the non-positive definiteness of such
matrices is at first addressed and suitable treatments regarding it are proposed. From the adjusted positive definite cross-spectral density
matrix a frequency response matrix is constructed which determines the turbulence vector as a linear filtration of Gaussian white noise.
Finally, an accurate state space modelling method is proposed which allows selection of an appropriate model order, and estimation of a state space model for the vector turbulence process incorporating its phase spectrum in one stage, and its results are compared with a conventional ARMA modelling method.
Abstract: Tufting carpet is a very suitable substrate for growing
microorganism such as pathogenic microbes, due to the direct touch
with human body, long washing periods and laying on the floor; in
fact there are 3 major problems: To risk human health, Prepare bad
odors and Destruction of the products.. In the presented research, for
investigation of presence most common microbes on polyester
tufting, first goods laid in a public place (in the corridor fair) for 30
days and the existence of some microbes were investigate on it with
two methods of enrichment in nutrient environments such as
thioglycolate and noutrunt brath, and shake the dust off the polyester
tufting onto cultivation mediums such as blood agar and noutrunt
agar. After the microorganism colonics are grown, the colonies were
separated and six microbial tests such as cataloes and sitrat were
carried out in five phases on the colonics for identifying the varieties
of bacteria. As a result of tests, 5 type of bacteria, such as
Escherichia coli, staphylococcus saprophytic as were identified. Each
of the mentioned bacteria can be seriously harmful for the heath of
human.
Abstract: Current advancements in nanotechnology are dependent
on the capabilities that can enable nano-scientists to extend their eyes
and hands into the nano-world. For this purpose, a haptics (devices
capable of recreating tactile or force sensations) based system for
AFM (Atomic Force Microscope) is proposed. The system enables
the nano-scientists to touch and feel the sample surfaces, viewed
through AFM, in order to provide them with better understanding of
the physical properties of the surface, such as roughness, stiffness and
shape of molecular architecture. At this stage, the proposed work uses
of ine images produced using AFM and perform image analysis to
create virtual surfaces suitable for haptics force analysis. The research
work is in the process of extension from of ine to online process
where interaction will be done directly on the material surface for
realistic analysis.
Abstract: In this paper, a delayed competitive system with the effect of toxic substances is investigated. With the aid of differential equations with piecewise constant arguments, a discrete analogue of continuous non-autonomous delayed competitive system with the effect of toxic substances is proposed. By using Gaines and Mawhin,s continuation theorem of coincidence degree theory, a easily verifiable sufficient condition for the existence of positive solutions of difference equations is obtained.
Abstract: This paper presents an algorithm based on the
wavelet decomposition, for feature extraction from the ECG signal
and recognition of three types of Ventricular Arrhythmias using
neural networks. A set of Discrete Wavelet Transform (DWT)
coefficients, which contain the maximum information about the
arrhythmias, is selected from the wavelet decomposition. After that a
novel clustering algorithm based on nature inspired algorithm (Ant
Colony Optimization) is developed for classifying arrhythmia types.
The algorithm is applied on the ECG registrations from the MIT-BIH
arrhythmia and malignant ventricular arrhythmia databases. We
applied Daubechies 4 wavelet in our algorithm. The wavelet
decomposition enabled us to perform the task efficiently and
produced reliable results.
Abstract: Behavior of dams against the seismic loads has been
studied by many researchers. Most of them proposed new numerical
methods to investigate the dam safety. In this paper, to study the
effect of nonlinear parameters of concrete in gravity dams, a twodimensional
approach was used including the finite element method,
staggered method and smeared crack approach. Effective parameters
in the models are physical properties of concrete such as modulus of
elasticity, tensile strength and specific fracture energy. Two different
models were used in foundation (mass-less and massed) in order to
determine the seismic response of concrete gravity dams. Results
show that when the nonlinear analysis includes the dam- foundation
interaction, the foundation-s mass, flexibility and radiation damping
are important in gravity dam-s response.