Abstract: Simplified coupled engine block-crankshaft models
based on beam theory provide an efficient substitute to engine
simulation in the design process. These models require accurate
definition of the main bearing stiffness. In this paper, an investigation
of this stiffness is presented. The clearance effect is studied using a
smooth bearing model. It is manifested for low shaft displacement.
The hydrodynamic assessment model shows that the oil film has no
stiffness for low loads and it is infinitely rigid for important loads.
The deformation stiffness is determined using a suitable finite
elements model based on real CADs. As a result, a main bearing
behaviour law is proposed. This behaviour law takes into account the
clearance, the hydrodynamic sustention and the deformation stiffness.
It ensures properly the transition from the configuration low rigidity
to the configuration high rigidity.
Abstract: The aim of this study was to investigate the effects of
supplementing the diluent of roosters' semen with different levels of
olive oil on motility, viability, morphology and acrosome integrity of
chicken spermatozoa after in vitro storage for up to 72 h. Semen was
collected from 60 White Layer males (62 wk of age) kept in
separated floor pens and randomly divided into six treatment groups
(10 males in each group). Experimental groups were as follows: T1
:fresh semen, T2 : semen extended 1:1 with Al – Daraji 2 diluent
(AD2D) alone, T3 – T6 :semen samples extended 1:1 with AD2D
supplemented with 2 ml, 4 ml, 6 ml or 8 ml of olive oil / 100 ml of
diluent, respectively. Semen samples were then stored at 5 °C for 24
h, 48 h or 72 h. There was a clear influence of diluent
supplementation with olive oil on the spermatozoa motility profile;
olive oil groups (T3, T4, T5 and T6) recorded the highest scores of
mass activity and individual motility during all storage periods
compared to T1 and T2 groups. In addition, the inclusion of olive oil
into semen diluent (T3, T4, T5 and T6) gave significantly higher
percentages of viable spermatozoa, normal morphologically
spermatozoa and intact acrosomes irrespective of storage period.
These results clearly show that supplementation the diluent of
roosters' semen with olive oil can improve semen quality when
semen samples in vitro stored at 5 °C for up to 72 h.
Abstract: The aim of this research is to evaluate surface
roughness and develop a multiple regression model for surface roughness as a function of cutting parameters during the turning of
flame hardened medium carbon steel with TiN-Al2O3-TiCN coated inserts. An experimental plan of work and signal-to-noise ratio (S/N)
were used to relate the influence of turning parameters to the
workpiece surface finish utilizing Taguchi methodology. The effects
of turning parameters were studied by using the analysis of variance (ANOVA) method. Evaluated parameters were feed, cutting speed,
and depth of cut. It was found that the most significant interaction among the considered turning parameters was between depth of cut and feed. The average surface roughness (Ra) resulted by TiN-Al2O3-
TiCN coated inserts was about 2.44 μm and minimum value was 0.74 μm. In addition, the regression model was able to predict values for surface roughness in comparison with experimental values within
reasonable limit.
Abstract: The recent drive for use of performance-based methodologies in design and assessment of structures in seismic areas has significantly increased the demand for the development of reliable nonlinear inelastic static pushover analysis tools. As a result, the adaptive pushover methods have been developed during the last decade, which unlike their conventional pushover counterparts, feature the ability to account for the effect that higher modes of vibration and progressive stiffness degradation might have on the distribution of seismic storey forces. Even in advanced pushover methods, little attention has been paid to the Unsymmetric structures. This study evaluates the seismic demands for three dimensional Unsymmetric-Plan buildings determined by the Displacement-based Adaptive Pushover (DAP) analysis, which has been introduced by Antoniou and Pinho [2004]. The capability of DAP procedure in capturing the torsional effects due to the irregularities of the structures, is investigated by comparing its estimates to the exact results, obtained from Incremental Dynamic Analysis (IDA). Also the capability of the procedure in prediction the seismic behaviour of the structure is discussed.
Abstract: Argument over the use of particular method in interlanguage pragmatics has increased recently. Researchers argued the advantages and disadvantages of each method either natural or elicited. Findings of different studies indicated that the use of one method may not provide enough data to answer all its questions. The current study investigated the validity of using multimethod approach in interlanguage pragmatics to understand the development of requests in Arabic as a second language (Arabic L2). To this end, the study adopted two methods belong to two types of data sources: the institutional discourse (natural data), and the role play (elicited data). Participants were 117 learners of Arabic L2 at the university level, representing four levels (beginners, low-intermediate, highintermediate, and advanced). Results showed that using two or more methods in interlanguage pragmatics affect the size and nature of data.
Abstract: In this paper we investigate the influence of external
noise on the inference of network structures. The purpose of our
simulations is to gain insights in the experimental design of microarray
experiments to infer, e.g., transcription regulatory networks
from microarray experiments. Here external noise means, that the
dynamics of the system under investigation, e.g., temporal changes of
mRNA concentration, is affected by measurement errors. Additionally
to external noise another problem occurs in the context of microarray
experiments. Practically, it is not possible to monitor the mRNA
concentration over an arbitrary long time period as demanded by the
statistical methods used to learn the underlying network structure. For
this reason, we use only short time series to make our simulations
more biologically plausible.
Abstract: This study numerically investigates the effects of Electrohydrodynamic on flow patterns and heat transfer enhancement within a cavity which is on the lower wall of channel. In this simulation, effects of using ground wire and ground plate on the flow patterns are compared. Moreover, the positions of electrode wire respecting with ground are tested in the range of angles θ = 0 - 180o. High electrical voltage exposes to air is 20 kV. Bulk mean velocity and temperature of inlet air are controlled at 0.1 m/s and 60 OC, respectively. The result shows when electric field is applied, swirling flow is appeared in the channel. In addition, swirling flow patterns in the main flow of using ground plate are widely spreader than that of using ground wire. Moreover, direction of swirling flow also affects the flow pattern and heat transfer in a cavity. These cause the using ground wire to give the maximum temperature and heat transfer higher than using ground plate. Furthermore, when the angle is at θ = 60o, high shear flow effect is obtained. This results show high strength of swirling flow and effective heat transfer enhancement.
Abstract: This paper presents a ray tracing simulation technique for characterize the radiowave propagation inside building. The implementation of an algorithm capable of enumerating a large number of propagation paths in interactive time for the special case of 2.5D. The effective dielectric constants of the building structure in the simulations are indicated. The study describes an efficient 2.5D model of ray tracing algorithm were compared with 3D model. The result of the first investigations is that the environment of the indoor wave significantly changes as we change the electric parameters of material constructions. A detailed analysis of the dependence of the indoor wave on the wideband characteristics of the channel: root mean square (RMS) delay spread characteristics and Mean excess delay, is also investigated.
Abstract: the cursive nature of the Arabic writing makes it
difficult to accurately segment characters or even deal with the whole
word efficiently. Therefore, in this paper, a printed Arabic sub-word
recognition system is proposed. The suggested algorithm utilizes
geometrical moments as descriptors for the separated sub-words.
Three types of moments are investigated and applied to the printed
sub-word images after dividing each image into multiple parts using
windowing. Since moments are global descriptors, the windowing
mechanism allows the moments to be applied to local regions of the
sub-word. The local-global mixture of the proposed scheme increases
the discrimination power of the moments while keeping the
simplicity and ease of use of moments.
Abstract: In this paper a three dimensional thermal model of a
sliding contact system is proposed for both steady-state or transient
conditions. The influence of contact force, electric current and
ambient temperature on the temperature distribution, has been
investigated. A thermal analysis of the different type of the graphite
material of fixed electric contact and its influence on contact system
temperature rise, has been performed. To validate the three
dimensional thermal model, some experimental tests have been done.
There is a good correlation between experimental and simulation
results.
Abstract: Repairing of the cracks by fiber metal laminates
(FMLs) was first done by some aeronautical laboratories in early
1970s. In this study, experimental investigations were done on the
effect of repairing the center-cracked aluminum plates using the FML
patches. The repairing processes were conducted to characterize the
response of the repaired structures to tensile tests. The composite
patches were made of one aluminum layer and two woven glassepoxy
composite layers. Three different crack lengths in three crack
angles and different patch lay-ups were examined. It was observed
for the lengthen cracks, the effect of increasing the crack angle on
ultimate tensile load in the structure was increase. It was indicated
that the situation of metal layer in the FML patches had an important
effect on the tensile response of the tested specimens. It was found
when the aluminum layer is farther, the ultimate tensile load has the
highest amount.
Abstract: Free and open source software is gaining popularity at
an unprecedented rate of growth. Organizations despite some
concerns about the quality have been using them for various
purposes. One of the biggest concerns about free and open source
software is post release software defects and their fixing. Many
believe that there is no appropriate support available to fix the bugs.
On the contrary some believe that due to the active involvement of
internet user in online forums, they become a major source of
communicating the identification and fixing of defects in open source
software. The research model of this empirical investigation
establishes and studies the relationship between open source software
defects and online public forums. The results of this empirical study
provide evidence about the realities of software defects myths of
open source software. We used a dataset consist of 616 open source
software projects covering a broad range of categories to study the
research model of this investigation. The results of this investigation
show that online forums play a significant role identifying and fixing
the defects in open source software.
Abstract: The unsteady wake of an EPPLER 361 airfoil in
pitching motion has been investigated in a subsonic wind tunnel by
hot-wire anemometry. The airfoil was given the pitching motion
about the one-quarter chord axis at reduced frequency of 0182.
Streamwise mean velocity profiles (wake profiles) were investigated
at several vertically aligned points behind the airfoil at one-quarter
chord downstream distance from trailing edge. Oscillation amplitude
and mean angle of attack were varied to determine the effects on
wake profiles. When the maximum dynamic angle of attack was
below the static stall angle of attack, weak effects on wake were
found by increasing oscillation amplitude and mean angle of attack.
But, for higher angles of attack strong unsteady effects were
appeared on the wake.
Abstract: Achieving success is a highly critical issue for the
companies to survive in a competitive business environment. The
construction industry is also an area where there is strong
competition due to a large number of construction contractors. There
have been many factors such as qualified employees, quality
workmanship and financial management that can lead to company
success in the construction industry. The aim of this study was to
investigate the critical factors leading to construction company
success. Within this context, a survey was carried out among 40
Turkish construction companies which are located in the Northwest
region of Turkey. In this survey, top-level managers and owners of
the companies were interviewed. The interviews took place over a
five month period between January and May 2007. Finally, the
ranking of the critical success factors has been determined by using
the Simple Multi Attribute Rating Technique (SMART). Based on
the results, business management, financial conditions and
owner/manager characteristics were determined as the most
important factors to company success.
Abstract: This study aims to assess the vulnerability and risk of
the coastal areas of Taijiang to abnormal oceanographic phenomena.
In addition, this study aims to investigate and collect data regarding
the disaster losses, land utilization, and other social, economic, and
environmental issues in these coastal areas to construct a coastal
vulnerability and risk map based on the obtained climate-change risk
assessment results. Considering the indexes of the three coastal
vulnerability dimensions, namely, man-made facilities, environmental
geography, and social economy, this study adopted the equal
weighting process and Analytic Hierarchy Process to analyze the
vulnerability of these coastal areas to disasters caused by climatic
changes. Among the areas with high coastal vulnerability to climatic
changes, three towns had the highest coastal vulnerability and four had
the highest relative vulnerability. Areas with lower disaster risks were
found to be increasingly vulnerable to disasters caused by climatic
changes as time progresses.
Abstract: Space Vector Modulation (SVM) is an optimum Pulse Width Modulation (PWM) technique for an inverter used in a variable frequency drive applications. It is computationally rigorous and hence limits the inverter switching frequency. Increase in switching frequency can be achieved using Neural Network (NN) based SVM, implemented on application specific chips. This paper proposes a neural network based SVM technique for a Voltage Source Inverter (VSI). The network proposed is independent of switching frequency. Different architectures are investigated keeping the total number of neurons constant. The performance of the inverter is compared for various switching frequencies for different architectures of NN based SVM. From the results obtained, the network with minimum resource and appropriate word length is identified. The bit precision required for this application is identified. The network with 8-bit precision is implemented in the IC XCV 400 and the results are presented. The performance of NN based general purpose SVM with higher bit precision is discussed.
Abstract: The main objective of this paper is a comparative
investigate in enhancement of damping power system oscillation via
coordinated design of the power system stabilizer (PSS) and static
synchronous series compensator (SSSC) and static synchronous
compensator (STATCOM). The design problem of FACTS-based
stabilizers is formulated as a GA based optimization problem. In this
paper eigenvalue analysis method is used on small signal stability of
single machine infinite bus (SMIB) system installed with SSSC and
STATCOM. The generator is equipped with a PSS. The proposed
stabilizers are tested on a weakly connected power system with
different disturbances and loading conditions. This aim is to enhance
both rotor angle and power system stability. The eigenvalue analysis
and non-linear simulation results are presented to show the effects of
these FACTS-based stabilizers and reveal that SSSC exhibits the best
effectiveness on damping power system oscillation.
Abstract: This paper addresses integration issues in supply
chain, and tries to investigate how different aspects of integration are
linked with some product features. Integration in this study is
interpreted as "internal", "upstream" (supply), and "downstream"
(demand). Two features of product innovative and quality are
considered. To examine the relationships between supply chain
integrations – as mentioned above, and product features, this research
follows the survey method in automotive industry.The results imply
that supply chain upstream integration has a higher impact on product
quality, comparing to internal and supply chain downstream
integrations. It is also found that the influence of supply chain
downstream integration on product innovation is greater than other
variables. In brief, this study mainly tackles the importance of
specific level of supply chain integrations and its effects on two
product features.
Abstract: Research results and optimal parameters investigation
of laser cut and profiling of diamond and quartz substrates by
femtosecond laser pulses are presented. Profiles 10 μm in width, ~25
μm in depth and several millimeters long were made. Investigation of
boundaries quality has been carried out with the use of AFM
«Vecco». Possibility of technological formation of profiles and
micro-holes in diamond and quartz substrates with nanometer-scale
boundaries is shown. Experimental results of multilayer dielectric
cover treatment are also presented. Possibility of precise upper layer
(thickness of 70–140 nm) removal is demonstrated. Processes of thin
metal film (60 nm and 350 nm thick) treatment are considered.
Isolation tracks (conductance ~ 10-11 S) 1.6–2.5 μm in width in
conductive metal layers are formed.