Abstract: In this work, we successfully extended one-dimensional differential transform method (DTM), by presenting and proving some theorems, to solving nonlinear high-order multi-pantograph equations. This technique provides a sequence of functions which converges to the exact solution of the problem. Some examples are given to demonstrate the validity and applicability of the present method and a comparison is made with existing results.
Abstract: There are reports of gas and oil wells fire due to different accidents. Many different methods are used for fire fighting in gas and oil industry. Traditional fire extinguishing techniques are mostly faced with many problems and are usually time consuming and needs lots of equipments. Besides, they cause damages to facilities, and create health and environmental problems. This article proposes innovative approach in fire extinguishing techniques in oil and gas industry, especially applicable for burning oil wells located offshore. Fire extinguishment employing a turbojet is a novel approach which can help to extinguishment the fire in short period of time. Divergent and convergent turbojets modeled in laboratory scale along with a high pressure flame were used. Different experiments were conducted to determine the relationship between output discharges of trumpet and oil wells. The results were corrected and the relationship between dimensionless parameters of flame and fire extinguishment distances and also the output discharge of turbojet and oil wells in specified distances are demonstrated by specific curves.
Abstract: Supplementation of palm vitamin E has been reported
to prevent loss of bone density in ovariectomised female rats. The
mechanism by which palm vitamin E exerts these effects is still
unknown. We hypothesized that palm vitamin E may act by
preventing the protein expression changes. Two dimensional poly
acyrilamide gel electrophoresis (2-D PAGE) and PD Quest software
genomic solutions Investigator (proteomics) was used to analyze the
differential protein expression profile in femoral and humeri bones
harvested from three groups of rats; sham-operated rats (SO),
ovariectomised rats (Ovx) and ovariectomised rats supplemented for
2 months with palm vitamin E. The results showed that there were
over 300 valued spot on each of the groups PVE and OVX as
compared to about 200 in SO. Comparison between the differential
protein expression between OVX and PVE groups showed that ten
spots were down –regulated in OVX but up-regulated in PVE. The
ten differential spots were separately named P1-P10. The
identification and understanding of the pathway of the differential
protein expression among the groups is ongoing and may account for
the molecular mechanism through which palm vitamin E exert its
anti-osteoporotic effect.
Abstract: Among all mechanical joining processes, welding has
been employed for its advantage in design flexibility, cost saving,
reduced overall weight and enhanced structural performance.
However, for structures made of relatively thin components, welding
can introduce significant buckling distortion which causes loss of
dimensional control, structural integrity and increased fabrication
costs. Different parameters can affect buckling behavior of welded
thin structures such as, heat input, welding sequence, dimension of
structure. In this work, a 3-D thermo elastic-viscoplastic finite
element analysis technique is applied to evaluate the effect of shell
dimensions on buckling behavior and entropy generation of welded
thin shells. Also, in the present work, the approximated longitudinal
transient stresses which produced in each time step, is applied to the
3D-eigenvalue analysis to ratify predicted buckling time and
corresponding eigenmode. Besides, the possibility of buckling
prediction by entropy generation at each time is investigated and it is
found that one can predict time of buckling with drawing entropy
generation versus out of plane deformation. The results of finite
element analysis show that the length, span and thickness of welded
thin shells affect the number of local buckling, mode shape of global
buckling and post-buckling behavior of welded thin shells.
Abstract: A topologically oriented neural network is very
efficient for real-time path planning for a mobile robot in changing
environments. When using a recurrent neural network for this
purpose and with the combination of the partial differential equation
of heat transfer and the distributed potential concept of the network,
the problem of obstacle avoidance of trajectory planning for a
moving robot can be efficiently solved. The related dimensional
network represents the state variables and the topology of the robot's
working space. In this paper two approaches to problem solution are
proposed. The first approach relies on the potential distribution of
attraction distributed around the moving target, acting as a unique
local extreme in the net, with the gradient of the state variables
directing the current flow toward the source of the potential heat. The
second approach considers two attractive and repulsive potential
sources to decrease the time of potential distribution. Computer
simulations have been carried out to interrogate the performance of
the proposed approaches.
Abstract: An experimental study is realized in order to verify the
Mini Heat Pipe (MHP) concept for cooling high power dissipation
electronic components and determines the potential advantages of
constructing mini channels as an integrated part of a flat heat pipe. A
Flat Mini Heat Pipe (FMHP) prototype including a capillary structure
composed of parallel rectangular microchannels is manufactured and
a filling apparatus is developed in order to charge the FMHP. The
heat transfer improvement obtained by comparing the heat pipe
thermal resistance to the heat conduction thermal resistance of a
copper plate having the same dimensions as the tested FMHP is
demonstrated for different heat input flux rates. Moreover, the heat
transfer in the evaporator and condenser sections are analyzed, and
heat transfer laws are proposed. In the theoretical part of this work, a
detailed mathematical model of a FMHP with axial microchannels is
developed in which the fluid flow is considered along with the heat
and mass transfer processes during evaporation and condensation.
The model is based on the equations for the mass, momentum and
energy conservation, which are written for the evaporator, adiabatic,
and condenser zones. The model, which permits to simulate several
shapes of microchannels, can predict the maximum heat transfer
capacity of FMHP, the optimal fluid mass, and the flow and thermal
parameters along the FMHP. The comparison between experimental
and model results shows the good ability of the numerical model to
predict the axial temperature distribution along the FMHP.
Abstract: Equal Channel Angular Pressing (ECAP) is currently
being widely investigated because of its potential to produce ultrafine
grained microstructures in metals and alloys. A sound
knowledge of the plastic deformation and strain distribution is
necessary for understanding the relationships between strain
inhomogeneity and die geometry. Considerable research has been
reported on finite element analysis of this process, assuming threedimensional
plane strain condition. However, the two-dimensional
models are not suitable due to the geometry of the dies, especially in
cylindrical ones. In the present work, three-dimensional simulation of
ECAP process was carried out for six outer corner radii (sharp to 10
mm in steps of 2 mm), with channel angle 105¶Çü▒, for strain hardening
aluminium alloy (AA 6101) using ABAQUS/Standard software.
Strain inhomogeneity is presented and discussed for all cases. Pattern
of strain variation along selected radial lines in the body of the workpiece
is presented. It is found from the results that the outer corner
has a significant influence on the strain distribution in the body of
work-piece. Based on inhomogeneity and average strain criteria,
there is an optimum outer corner radius.
Abstract: This study offers a new simple method for assessing
an axial part-through crack in a pipe wall. The method utilizes simple
approximate expressions for determining the fracture parameters K,
J, and employs these parameters to determine critical dimensions of a
crack on the basis of equality between the J-integral and the J-based
fracture toughness of the pipe steel. The crack tip constraint is taken
into account by the so-called plastic constraint factor C, by which the
uniaxial yield stress in the J-integral equation is multiplied. The
results of the prediction of the fracture condition are verified by burst
tests on test pipes.
Abstract: Performance management seems to be essential in
business area and is also an exciting topic. Despite significant and
myriads of research efforts, performance management guide today as a
rigorous approach is still in an immature state and metrics are often
selected based on intuitive and heuristic approach. In R&D side, the
difficulty to guide the proper performance management is even more
increasing due to the natural characteristics of R&D such as unique or
domain-specific problems. In our approach, we present R&D
performance management guide considering various characteristics of
R&D side: performance evaluation objectives, dimensions, metrics,
and uncertainties of R&D sector.
Abstract: The automatic discrimination of seismic signals is an important practical goal for earth-science observatories due to the large amount of information that they receive continuously. An essential discrimination task is to allocate the incoming signal to a group associated with the kind of physical phenomena producing it. In this paper, two classes of seismic signals recorded routinely in geophysical laboratory of the National Center for Scientific and Technical Research in Morocco are considered. They correspond to signals associated to local earthquakes and chemical explosions. The approach adopted for the development of an automatic discrimination system is a modular system composed by three blocs: 1) Representation, 2) Dimensionality reduction and 3) Classification. The originality of our work consists in the use of a new wavelet called "modified Mexican hat wavelet" in the representation stage. For the dimensionality reduction, we propose a new algorithm based on the random projection and the principal component analysis.
Abstract: Ant colony optimization (ACO) and its variants are
applied extensively to resolve various continuous optimization
problems. As per the various diversification and intensification
schemes of ACO for continuous function optimization, researchers
generally consider components of multidimensional state space to
generate the new search point(s). However, diversifying to a new
search space by updating only components of the multidimensional
vector may not ensure that the new point is at a significant distance
from the current solution. If a minimum distance is not ensured
during diversification, then there is always a possibility that the
search will end up with reaching only local optimum. Therefore, to
overcome such situations, a Mahalanobis distance-based
diversification with Nelder-Mead simplex-based search scheme for
each ant is proposed for the ACO strategy. A comparative
computational run results, based on nine nonlinear standard test
problems, confirms that the performance of ACO is improved
significantly with the integration of the proposed schemes in the
ACO.
Abstract: In this paper, the effects of radiation, chemical
reaction and double dispersion on mixed convection heat and mass
transfer along a semi vertical plate are considered. The plate is
embedded in a Newtonian fluid saturated non - Darcy (Forchheimer
flow model) porous medium. The Forchheimer extension and first
order chemical reaction are considered in the flow equations. The
governing sets of partial differential equations are nondimensionalized
and reduced to a set of ordinary differential
equations which are then solved numerically by Fourth order Runge–
Kutta method. Numerical results for the detail of the velocity,
temperature, and concentration profiles as well as heat transfer rates
(Nusselt number) and mass transfer rates (Sherwood number) against
various parameters are presented in graphs. The obtained results are
checked against previously published work for special cases of the
problem and are found to be in good agreement.
Abstract: A method is presented for obtaining the error probability for block codes. The method is based on the eigenvalueeigenvector properties of the code correlation matrix. It is found that under a unary transformation and for an additive white Gaussian noise environment, the performance evaluation of a block code becomes a one-dimensional problem in which only one eigenvalue and its corresponding eigenvector are needed in the computation. The obtained error rate results show remarkable agreement between simulations and analysis.
Abstract: A two dimensional numerical simulation has been
performed for incompressible and compressible fluid flow through
microchannels in slip flow regime. The Navier-Stokes equations have
been solved in conjunction with Maxwell slip conditions for
modeling flow field associated with slip flow regime. The wall
roughness is simulated with triangular microelements distributed on
wall surfaces to study the effects of roughness on fluid flow. Various
Mach and Knudsen numbers are used to investigate the effects of
rarefaction as well as compressibility. It is found that rarefaction has
more significant effect on flow field in microchannels with higher
relative roughness. It is also found that compressibility has more
significant effects on Poiseuille number when relative roughness
increases. In addition, similar to incompressible models the increase
in average fRe is more significant at low Knudsen number flows but
the increase of Poiseuille number duo to relative roughness is sharper
for compressible models. The numerical results have also validated
with some available theoretical and experimental relations and good
agreements have been seen.
Abstract: Soft clays are defined as cohesive soil whose water
content is higher than its liquid limits. Thus, soil-cement mixing is
adopted to improve the ground conditions by enhancing the strength
and deformation characteristics of the soft clays. For the above
mentioned reasons, a series of laboratory tests were carried out to
study some fundamental mechanical properties of cement stabilized
soft clay. The test specimens were prepared by varying the portion of
ordinary Portland cement to the soft clay sample retrieved from the
test site of RECESS (Research Centre for Soft Soil). Comparisons
were made for both homogeneous and columnar system specimens
by relating the effects of cement stabilized clay of for 0, 5 and 10 %
cement and curing for 3, 28 and 56 days. The mechanical properties
examined included one-dimensional compressibility and undrained
shear strength. For the mechanical properties, both homogeneous and
columnar system specimens were prepared to examine the effect of
different cement contents and curing periods on the stabilized soil.
The one-dimensional compressibility test was conducted using an
oedometer, while a direct shear box was used for measuring the
undrained shear strength. The higher the value of cement content, the
greater is the enhancement of the yield stress and the decrease of
compression index. The value of cement content in a specimen is a
more active parameter than the curing period.
Abstract: Abdominal aortic aneurysms rupture (AAAs) is one of the main causes of death in the world. This is a very complex phenomenon that usually occurs “without previous warning". Currently, criteria to assess the aneurysm rupture risk (peak diameter and growth rate) can not be considered as reliable indicators. In a first approach, the main geometric parameters of aneurysms have been linked into five biomechanical factors. These are combined to obtain a dimensionless rupture risk index, RI(t), which has been validated preliminarily with a clinical case and others from literature. This quantitative indicator is easy to understand, it allows estimating the aneurysms rupture risks and it is expected to be able to identify the one in aneurysm whose peak diameter is less than the threshold value. Based on initial results, a broader study has begun with twelve patients from the Clinic Hospital of Valladolid-Spain, which are submitted to periodic follow-up examinations.
Abstract: Concerning the measurement of friction properties of
textiles and fabrics using Kawabata Evaluation System (KES), whose
output is constrained to the surface friction factor of fabric, and no
other data would be generated; this research has been conducted to
gain information about surface roughness regarding its surface
friction factor. To assess roughness properties of light nonwovens, a
3-dimensional model of a surface has been simulated with regular
sinuous waves through it as an ideal surface. A new factor was
defined, namely Surface Roughness Factor, through comparing
roughness properties of simulated surface and real specimens. The
relation between the proposed factor and friction factor of specimens
has been analyzed by regression, and results showed a meaningful
correlation between them. It can be inferred that the new presented
factor can be used as an acceptable criterion for evaluating the
roughness properties of light nonwoven fabrics.
Abstract: The use of new technologies such internet (e-mail, chat
rooms) and cell phones has steeply increased in recent years.
Especially among children and young people, use of technological
tools and equipments is widespread. Although many teachers and
administrators now recognize the problem of school bullying, few are
aware that students are being harassed through electronic
communication. Referred to as electronic bullying, cyber bullying, or
online social cruelty, this phenomenon includes bullying through email,
instant messaging, in a chat room, on a website, or through
digital messages or images sent to a cell phone. Cyber bullying is
defined as causing deliberate/intentional harm to others using internet
or other digital technologies. It has a quantitative research design nd
uses relational survey as its method. The participants consisted of
300 secondary school students in the city of Konya, Turkey. 195
(64.8%) participants were female and 105 (35.2%) were male. 39
(13%) students were at grade 1, 187 (62.1%) were at grade 2 and 74
(24.6%) were at grade 3. The “Cyber Bullying Question List"
developed by Ar─▒cak (2009) was given to students. Following
questions about demographics, a functional definition of cyber
bullying was provided. In order to specify students- human values,
“Human Values Scale (HVS)" developed by Dilmaç (2007) for
secondary school students was administered. The scale consists of 42
items in six dimensions. Data analysis was conducted by the primary
investigator of the study using SPSS 14.00 statistical analysis
software. Descriptive statistics were calculated for the analysis of
students- cyber bullying behaviour and simple regression analysis was
conducted in order to test whether each value in the scale could
explain cyber bullying behaviour.
Abstract: In this work, the primary compressive strength
components of human femur trabecular bone are qualitatively
assessed using image processing and wavelet analysis. The Primary
Compressive (PC) component in planar radiographic femur trabecular
images (N=50) is delineated by semi-automatic image processing
procedure. Auto threshold binarization algorithm is employed to
recognize the presence of mineralization in the digitized images. The
qualitative parameters such as apparent mineralization and total area
associated with the PC region are derived for normal and abnormal
images.The two-dimensional discrete wavelet transforms are utilized
to obtain appropriate features that quantify texture changes in medical
images .The normal and abnormal samples of the human femur are
comprehensively analyzed using Harr wavelet.The six statistical
parameters such as mean, median, mode, standard deviation, mean
absolute deviation and median absolute deviation are derived at level
4 decomposition for both approximation and horizontal wavelet
coefficients. The correlation coefficient of various wavelet derived
parameters with normal and abnormal for both approximated and
horizontal coefficients are estimated. It is seen that in almost all cases
the abnormal show higher degree of correlation than normals. Further
the parameters derived from approximation coefficient show more
correlation than those derived from the horizontal coefficients. The
parameters mean and median computed at the output of level 4 Harr
wavelet channel was found to be a useful predictor to delineate the
normal and the abnormal groups.
Abstract: In this work, we obtain some analytic solutions for the (3+1)-dimensional breaking soliton after obtaining its Hirota-s bilinear form. Our calculations show that, three-wave method is very easy and straightforward to solve nonlinear partial differential equations.