Abstract: The number of Ground Motion Prediction Equations
(GMPEs) used for predicting peak ground acceleration (PGA) and
the number of earthquake recordings that have been used for fitting
these equations has increased in the past decades. The current PF-L
database contains 3550 recordings. Since the GMPEs frequently
model the peak ground acceleration the goal of the present study was
to refit a selection of 44 of the existing equation models for PGA in
light of the latest data. The algorithm Levenberg-Marquardt was used
for fitting the coefficients of the equations and the results are
evaluated both quantitatively by presenting the root mean squared
error (RMSE) and qualitatively by drawing graphs of the five best
fitted equations. The RMSE was found to be as low as 0.08 for the
best equation models. The newly estimated coefficients vary from the
values published in the original works.
Abstract: At certain depths during large diameter displacement
pile driving, rebound well over 0.25 inches was experienced,
followed by a small permanent-set during each hammer blow. High
pile rebound (HPR) soils may stop the pile driving and results in a
limited pile capacity. In some cases, rebound leads to pile damage,
delaying the construction project, and the requiring foundations
redesign. HPR was evaluated at seven Florida sites, during driving of
square precast, prestressed concrete piles driven into saturated, fine
silty to clayey sands and sandy clays. Pile Driving Analyzer (PDA)
deflection versus time data recorded during installation, was used to
develop correlations between cone penetrometer (CPT) pore-water
pressures, pile displacements and rebound. At five sites where piles
experienced excessive HPR with minimal set, the pore pressure
yielded very high positive values of greater than 20 tsf. However, at
the site where the pile rebounded, followed by an acceptable
permanent-set, the measured pore pressure ranged between 5 and 20
tsf. The pore pressure exhibited values of less than 5 tsf at the site
where no rebound was noticed. In summary, direct correlations
between CPTu pore pressure and rebound were produced, allowing
identification of soils that produce HPR.
Abstract: Negative pressure phenomenon appears in many
thermodynamic, geophysical and biophysical processes in the Nature
and technological systems. For more than 100 years of the laboratory
researches beginning from F. M. Donny’s tests, the great values of
negative pressure have been achieved. But this phenomenon has not
been practically applied, being only a nice lab toy due to the special
demands for the purity and homogeneity of the liquids for its
appearance. The possibility of creation of direct wave of negative
pressure in real heterogeneous liquid systems was confirmed
experimentally under the certain kinetic and hydraulic conditions.
The negative pressure can be considered as the factor of both useful
and destroying energies. The new approach to generation of the
negative pressure waves in impure, unclean fluids has allowed the
creation of principally new energy saving technologies and
installations to increase the effectiveness and efficiency of different
production processes. It was proved that the negative pressure is one
of the main factors causing hard troubles in some technological and
natural processes. Received results emphasize the necessity to take
into account the role of the negative pressure as an energy factor in
evaluation of many transient thermohydrodynamic processes in the
Nature and production systems.
Abstract: Equal channel angular pressing (ECAP) of
commercial Al-Mg-Si alloy was conducted using two strain rates.
The ECAP processing was conducted at room temperature and at
250°C. Route A was adopted up to a total number of four passes in
the present work. Structural evolution of the aluminum alloy discs
was investigated before and after ECAP processing using optical
microscopy (OM). Following ECAP, simple compression tests and
Vicker’s hardness were performed. OM micrographs showed that, the
average grain size of the as-received Al-Mg-Si disc tends to be larger
than the size of the ECAP processed discs. Moreover, significant
difference in the grain morphologies of the as-received and processed
discs was observed. Intensity of deformation was observed via the
alignment of the Al-Mg-Si consolidated particles (grains) in the
direction of shear, which increased with increasing the number of
passes via ECAP. Increasing the number of passes up to 4 resulted in
increasing the grains aspect ratio up to ~5. It was found that the
pressing temperature has a significant influence on the
microstructure, Hv-values, and compressive strength of the processed
discs. Hardness measurements demonstrated that 1-pass resulted in
increase of Hv-value by 42% compared to that of the as-received
alloy. 4-passes of ECAP processing resulted in additional increase in
the Hv-value. A similar trend was observed for the yield and
compressive strength. Experimental data of the Hv-values
demonstrated that there is a lack of any significant dependence on the
processing strain rate.
Abstract: Burnishing is increasingly used as a finishing operation to improve surface roughness and surface hardness. This can be achieved by applying a hard ball or roller onto metallic surfaces under pressure, in order to achieve many advantages in the metallic surface. In the present work, the feed rate, speed and force have been considered as the basic burnishing parameters to study the surface roughness and surface hardness of metallic matrix composites. The considered metal matrix composites were made from Aluminum-Magnesium-Graphite with five different weight percentage of graphite. Both effects of burnishing parameters mentioned above and the graphite percentage on the surface hardness and surface roughness of the metallic matrix composites were studied. The results of this investigation showed that the surface hardness of the metallic composites increases with the increase of the burnishing force and decreases with the increase in the burnishing feed rate and burnishing speed. The surface roughness of the metallic composites decreases with the increasing of the burnishing force, feed rate, and speed to certain values, then it starts to increase. On the other hand, the increase in the weight percentage of the graphite in the considered composites causes a decrease in the surface hardness and an increase in the surface roughness.
Abstract: Early pre-code reinforced concrete structures present
undetermined resistance to earthquakes. This situation is particularly
unacceptable in the case of essential structures, such as healthcare
structures and pilgrims' houses. Amongst these, an existing old RC
building in Madinah city (KSA) is seismically evaluated with and
without infill wall and their dynamic characteristics are compared
with measured values in the field using ambient vibration
measurements (AVM). After updating the mathematical models for
this building with the experimental results, three dimensional
pushover analysis (Nonlinear static analysis) was carried out using
commercial structural analysis software incorporating inelastic
material properties for concrete, infill and steel. The purpose of this
analysis is to evaluate the expected performance of structural systems
by estimating, strength and deformation demands in design, and
comparing these demands to available capacities at the performance
levels of interest. The results summarized and discussed.
Abstract: Testing the first year students of Informatics at the
University of Debrecen revealed that students start their tertiary
studies in programming with a low level of programming knowledge
and algorithmic skills. The possible reasons which lead the students
to this very unfortunate result were examined. The results of the test
were compared to the students’ results in the school leaving exams
and to their self-assessment values. It was found that there is only a
slight connection between the students’ results in the test and in the
school leaving exams, especially at intermediate level. Beyond this,
the school leaving exams do not seem to enable students to evaluate
their own abilities.
Abstract: Starting in 2020, an EU-wide CO2-limitation of
95 g/km is scheduled for the average of an OEMs passenger car fleet.
Taking that into consideration additional improvement measures of
the Diesel cycle are necessary in order to reduce fuel consumption
and emissions while boosting, or at the least, keeping performance
values at the same time.
The present article deals with the possibilities of an optimized
air/water charge air cooler, also called iCAC (indirect Charge Air
Cooler) for a Diesel passenger car amongst extreme-boundary
conditions. In this context, the precise objective was to show the
impact of improved intercooling with reference to the engine working
process (fuel consumption and NOx-emissions). Several extremeboundaries
- e.g. varying ambient temperatures or mountainous
routes - that will become very important in the near future regarding
RDE (Real Driving emissions) were subject of the investigation.
With the introduction of RDE in 2017 (EU6c measure), the
controversial NEDC (New European Driving Cycle) will belong to
the past and the OEMs will have to avoid harmful emissions in any
conceivable real life situation.
This is certainly going to lead to optimization-measurements at the
powertrain, which again is going to make the implementation of
iCACs, presently solely used for the premium class, more and more
attractive for compact class cars. The investigations showed a benefit
in FC between 1 and 3% for the iCAC in real world conditions.
Abstract: In this work, neural networks methods MLP type were
applied to a database from an array of six sensors for the detection of
three toxic gases. The choice of the number of hidden layers and the
weight values are influential on the convergence of the learning
algorithm. We proposed, in this article, a mathematical formula to
determine the optimal number of hidden layers and good weight
values based on the method of back propagation of errors. The results
of this modeling have improved discrimination of these gases and
optimized the computation time. The model presented here has
proven to be an effective application for the fast identification of
toxic gases.
Abstract: A field experiment was carried out at Arab El-
Awammer Research Station, Agric. Res. Center. Assiut Governorate
during summer seasons of 2013 and 2014. The present study assessed
the effect of cowpea with maize intercropping on yield and its
components. The experiment comprised of three treatments (sole
cowpea, sole maize and cowpea-maize intercrop). The experimental
design was a randomized complete block with four replications.
Results indicated that intercropped maize plants with cowpea,
exhibited greater potentiality and resulted in higher values of most of
the studied criteria viz., plant height, number of ears/plant, number of
rows/ear, number of grains/row, grains weight/ear, 100–grain weight
and straw and grain yields. Fresh and dry forage yields of cowpea
were lower in intercropping with maize than sole. Furthermore, the
combined of the two seasons revealed that the total Land Equivalent
Ratio (LER) between cowpea and maize was 1.65. The Aggressivity
(A) maize was 0.45 and cowpea was -0.45. This showed that maize
was the dominant crop, whereas cowpea was the dominated. The
Competitive Ratio (CR) indicated that maize more competitive than
cowpea, maize was 1.75 and cowpea was 0.57. The Actual Yield
Loss (AYL) maize was 0.05 and cowpea was -0.40. The Monetary
Advantage Index (MAI) was 2360.80.
Abstract: Securing the confidential data transferred via wireless
network remains a challenging problem. It is paramount to ensure
that data are accessible only by the legitimate users rather than by the
attackers. One of the most serious threats to organization is jamming,
which disrupts the communication between any two pairs of nodes.
Therefore, designing an attack-defending scheme without any packet
loss in data transmission is an important challenge. In this paper,
Dependence based Malicious Route Defending DMRD Scheme has
been proposed in multi path routing environment to prevent jamming
attack. The key idea is to defend the malicious route to ensure
perspicuous transmission. This scheme develops a two layered
architecture and it operates in two different steps. In the first step,
possible routes are captured and their agent dependence values are
marked using triple agents. In the second step, the dependence values
are compared by performing comparator filtering to detect malicious
route as well as to identify a reliable route for secured data
transmission. By simulation studies, it is observed that the proposed
scheme significantly identifies malicious route by attaining lower
delay time and route discovery time; it also achieves higher
throughput.
Abstract: This paper investigates the viability of using carbon
fiber reinforced epoxy composites modified with carbon nanotubes to
strengthening reinforced concrete (RC) columns. Six RC columns
was designed and constructed according to ASCE standards. The
columns were wrapped using carbon fiber sheets impregnated with
either neat epoxy or CNTs modified epoxy. These columns were then
tested under concentric axial loading. Test results show that;
compared to the unwrapped specimens; wrapping concrete columns
with carbon fiber sheet embedded in CNTs modified epoxy resulted
in an increase in its axial load resistance, maximum displacement,
and toughness values by 24%, 109% and 232%, respectively. These
results reveal that adding CNTs into epoxy resin enhanced the
confinement effect, specifically, increased the axial load resistance,
maximum displacement, and toughness values by 11%, 6%, and
19%, respectively compared with columns strengthening with carbon
fiber sheet embedded in neat epoxy.
Abstract: Safety is one of the most important considerations
when buying a new car. While active safety aims at avoiding
accidents, passive safety systems such as airbags and seat belts
protect the occupant in case of an accident. In addition to legal
regulations, organizations like Euro NCAP provide consumers with
an independent assessment of the safety performance of cars and
drive the development of safety systems in automobile industry.
Those ratings are mainly based on injury assessment reference values
derived from physical parameters measured in dummies during a car
crash test.
The components and sub-systems of a safety system are designed
to achieve the required restraint performance. Sled tests and other
types of tests are then carried out by car makers and their suppliers
to confirm the protection level of the safety system. A Knowledge
Discovery in Databases (KDD) process is proposed in order to
minimize the number of tests. The KDD process is based on the
data emerging from sled tests according to Euro NCAP specifications.
About 30 parameters of the passive safety systems from different data
sources (crash data, dummy protocol) are first analysed together with
experts opinions. A procedure is proposed to manage missing data
and validated on real data sets. Finally, a procedure is developed to
estimate a set of rough initial parameters of the passive system before
testing aiming at reducing the number of tests.
Abstract: In this paper, the dynamic characteristics of a threelobe
journal bearing lubricated with micropolar fluids are determined
by the linear stability theory. Lubricating oil containing additives and
contaminants is modelled as micropolar fluid. The modified
Reynolds equation is obtained using the micropolar lubrication theory
.The finite difference technique has been used to determine the
solution of the modified Reynolds equation. The dynamic
characteristics in terms of stiffness, damping coefficients, the critical
mass and whirl ratio are determined for various values of size of
material characteristic length and the coupling number. The
computed results show that the three-lobe bearing lubricated with
micropolar fluid exhibits better stability compared with that
lubricated with Newtonian fluid. According to the results obtained,
the effect of the parameter micropolar fluid is remarkable on the
dynamic characteristics and stability of the three-lobe bearing.
Abstract: Many of the ever-growing elderly population require
exercise, such as running, for health management. One important
element of a runner’s training is the choice of shoes for exercise; shoes
are important because they provide the interface between the feet and
road. When we purchase shoes, we may instinctively choose a pair
after trying on many different pairs of shoes. Selecting the shoes
instinctively may work, but it does not guarantee a suitable fit for
running activities. Therefore, if we could select suitable shoes for each
runner from the viewpoint of brain activities, it would be helpful for
validating shoe selection. In this paper, we describe how brain
activities show different characteristics during particular task,
corresponding to different properties of shoes. Using five subjects, we
performed a verification experiment, applying weight, softness, and
flexibility as shoe properties. In order to affect the shoe property’s
differences to the brain, subjects run for 10 min. Before and after
running, subjects conducted a paced auditory serial addition task
(PASAT) as the particular task; and the subjects’ brain activities
during the PASAT are evaluated based on oxyhemoglobin and
deoxyhemoglobin relative concentration changes, measured by
near-infrared spectroscopy (NIRS). When the brain works actively,
oxihemoglobin and deoxyhemoglobin concentration drastically
changes; therefore, we calculate the maximum values of concentration
changes. In order to normalize relative concentration changes after
running, the maximum value are divided by before running maximum
value as evaluation parameters. The classification of the groups of
shoes is expressed on a self-organizing map (SOM). As a result,
deoxyhemoglobin can make clusters for two of the three types of
shoes.
Abstract: The objective of meta-analysis is to combine results
from several independent studies in order to create generalization
and provide evidence base for decision making. But recent studies
show that the magnitude of effect size estimates reported in many
areas of research significantly changed over time and this can
impair the results and conclusions of meta-analysis. A number of
sequential methods have been proposed for monitoring the effect
size estimates in meta-analysis. However they are based on statistical
theory applicable only to fixed effect model (FEM) of meta-analysis.
For random-effects model (REM), the analysis incorporates the
heterogeneity variance, τ 2 and its estimation create complications.
In this paper we study the use of a truncated CUSUM-type test with
asymptotically valid critical values for sequential monitoring in REM.
Simulation results show that the test does not control the Type I error
well, and is not recommended. Further work required to derive an
appropriate test in this important area of applications.
Abstract: Nanocrystalline powders of the lead-free piezoelectric
material, tantalum-substituted potassium sodium niobate
(K0.5Na0.5)(Nb0.9Ta0.1)O3 (KNNT), were produced using a Retsch
PM100 planetary ball mill by setting the milling time to 15h, 20h,
25h, 30h, 35h and 40h, at a fixed speed of 250rpm. The average
particle size of the milled powders was found to decrease from 12nm
to 3nm as the milling time increases from 15h to 25h, which is in
agreement with the existing theoretical model. An anomalous
increase to 98nm and then a drop to 3nm in the particle size were
observed as the milling time further increases to 30h and 40h
respectively. Various sizes of these starting KNNT powders were
used to investigate the effect of milling time on the microstructure,
dielectric properties, phase transitions and piezoelectric properties of
the resulting KNNT ceramics. The particle size of starting KNNT
was somewhat proportional to the grain size. As the milling time
increases from 15h to 25h, the resulting ceramics exhibit
enhancement in the values of relative density from 94.8% to 95.8%,
room temperature dielectric constant (εRT) from 878 to 1213, and
piezoelectric charge coefficient (d33) from 108pC/N to 128pC/N. For
this range of ceramic samples, grain size refinement suppresses the
maximum dielectric constant (εmax), shifts the Curie temperature (Tc)
to a lower temperature and the orthorhombic-tetragonal phase
transition (Tot) to a higher temperature. Further increase of milling
time from 25h to 40h produces a gradual degradation in the values of
relative density, εRT, and d33 of the resulting ceramics.
Abstract: An algorithm is a well-defined procedure that takes
some input in the form of some values, processes them and gives the
desired output. It forms the basis of many other algorithms such as
searching, pattern matching, digital filters etc., and other applications
have been found in database systems, data statistics and processing,
data communications and pattern matching. This paper introduces
algorithmic “Enhanced Bidirectional Selection” sort which is
bidirectional, stable. It is said to be bidirectional as it selects two
values smallest from the front and largest from the rear and assigns
them to their appropriate locations thus reducing the number of
passes by half the total number of elements as compared to selection
sort.
Abstract: In this paper, Least Mean Square (LMS) adaptive
noise reduction algorithm is proposed to enhance the speech signal
from the noisy speech. In this, the speech signal is enhanced by
varying the step size as the function of the input signal. Objective and
subjective measures are made under various noises for the proposed
and existing algorithms. From the experimental results, it is seen that
the proposed LMS adaptive noise reduction algorithm reduces Mean
square Error (MSE) and Log Spectral Distance (LSD) as compared to
that of the earlier methods under various noise conditions with
different input SNR levels. In addition, the proposed algorithm
increases the Peak Signal to Noise Ratio (PSNR) and Segmental SNR
improvement (ΔSNRseg) values; improves the Mean Opinion Score
(MOS) as compared to that of the various existing LMS adaptive
noise reduction algorithms. From these experimental results, it is
observed that the proposed LMS adaptive noise reduction algorithm
reduces the speech distortion and residual noise as compared to that
of the existing methods.
Abstract: A key issue in seismic risk analysis within the context
of Performance-Based Earthquake Engineering is the evaluation of
the expected seismic damage of structures under a specific
earthquake ground motion. The assessment of the seismic
performance strongly depends on the choice of the seismic Intensity
Measure (IM), which quantifies the characteristics of a ground
motion that are important to the nonlinear structural response. Several
conventional IMs of ground motion have been used to estimate their
damage potential to structures. Yet, none of them has been proved to
be able to predict adequately the seismic damage. Therefore,
alternative, scalar intensity measures, which take into account not
only ground motion characteristics but also structural information
have been proposed. Some of these IMs are based on integration of
spectral values over a range of periods, in an attempt to account for
the information that the shape of the acceleration, velocity or
displacement spectrum provides. The adequacy of a number of these
IMs in predicting the structural damage of 3D R/C buildings is
investigated in the present paper. The investigated IMs, some of
which are structure specific and some are non structure-specific, are
defined via integration of spectral values. To achieve this purpose
three symmetric in plan R/C buildings are studied. The buildings are
subjected to 59 bidirectional earthquake ground motions. The two
horizontal accelerograms of each ground motion are applied along
the structural axes. The response is determined by nonlinear time
history analysis. The structural damage is expressed in terms of the
maximum interstory drift as well as the overall structural damage
index. The values of the aforementioned seismic damage measures
are correlated with seven scalar ground motion IMs. The comparative
assessment of the results revealed that the structure-specific IMs
present higher correlation with the seismic damage of the three
buildings. However, the adequacy of the IMs for estimation of the
structural damage depends on the response parameter adopted.
Furthermore, it was confirmed that the widely used spectral
acceleration at the fundamental period of the structure is a good
indicator of the expected earthquake damage level.