Abstract: In this paper, a nonlinear Finite Element Analysis
(FEA) was carried out using ANSYS software to build a model able
of predicting the behavior of Reinforced Concrete (RC) beams with
unbonded reinforcement. The FEA model was compared to existing
experimental data by other researchers. The existing experimental
data consisted of 16 beams that varied from structurally sound beams
to beams with unbonded reinforcement with different unbonded
lengths and reinforcement ratios. The model was able to predict the
ultimate flexural strength, load-deflection curve, and crack pattern of
concrete beams with unbonded reinforcement. It was concluded that
when the when the unbonded length is less than 45% of the span,
there will be no decrease in the ultimate flexural strength due to the
loss of bond between the steel reinforcement and the surrounding
concrete regardless of the reinforcement ratio. Moreover, when the
reinforcement ratio is relatively low, there will be no decrease in
ultimate flexural strength regardless of the length of unbond.
Abstract: Vegetation affects the mean and turbulent flow
structure. It may increase flood risks and sediment transport.
Therefore, it is important to develop analytical approaches for the bed
shear stress on vegetated bed, to predict resistance caused by
vegetation. In the recent years, experimental and numerical models
have both been developed to model the effects of submerged
vegetation on open-channel flow. In this paper, different analytic
models are compared and tested using the criteria of deviation, to
explore their capacity for predicting the mean velocity and select the
suitable one that will be applied in real case of rivers. The
comparison between the measured data in vegetated flume and
simulated mean velocities indicated, a good performance, in the case
of rigid vegetation, whereas, Huthoff model shows the best
agreement with a high coefficient of determination (R2=80%) and the
smallest error in the prediction of the average velocities.
Abstract: In the present work, the alloy of Bismuth-lead is
prepared on the basis of percentage of molecular weight 9:1, 5:5 and
1:9 ratios and grown by Zone- Refining Technique under a vacuum
atmosphere. The EDAX of these samples are done and the results are
reported. Micro hardness test has been used as an alternative test for
measuring material’s tensile properties. The effect of temperature and
load on the hardness of the grown alloy has been studied. Further the
comparative studies of work hardening coefficients are reported.
Abstract: In this paper, a new trend for improvement in semianalytical
method based on scale boundaries in order to solve the 2D
elastodynamic problems is provided. In this regard, only the
boundaries of the problem domain discretization are by specific subparametric
elements. Mapping functions are uses as a class of higherorder
Lagrange polynomials, special shape functions, Gauss-Lobatto-
Legendre numerical integration, and the integral form of the weighted
residual method, the matrix is diagonal coefficients in the equations
of elastodynamic issues. Differences between study conducted and
prior research in this paper is in geometry production procedure of
the interpolation function and integration of the different is selected.
Validity and accuracy of the present method are fully demonstrated
through two benchmark problems which are successfully modeled
using a few numbers of DOFs. The numerical results agree very well
with the analytical solutions and the results from other numerical
methods.
Abstract: The California Bearing Ratio (CBR) has been
acknowledged as an important parameter to characterize the bearing
capacity of earth structures, such as earth dams, road embankments,
airport runways, bridge abutments and pavements. Technically, the
CBR test can be carried out in the laboratory or in the field. The CBR
test is time-consuming and is infrequently performed due to the
equipment needed and the fact that the field moisture content keeps
changing over time. Over the years, many correlations have been
developed for the prediction of CBR by various researchers,
including the dynamic cone penetrometer, undrained shear strength
and Clegg impact hammer. This paper reports and discusses some of
the results from a study on the prediction of CBR. In the current
study, the CBR test was performed in the laboratory on some finegrained
subgrade soils collected from various locations in Victoria.
Based on the test results, a satisfactory empirical correlation was
found between the CBR and the physical properties of the
experimental soils.
Abstract: This paper presents the details of a numerical study of
buckling and post buckling behaviour of laminated carbon fiber
reinforced plastic (CFRP) thin-walled cylindrical shell under axial
compression using asymmetric meshing technique (AMT) by
ABAQUS. AMT is considered to be a new perturbation method to
introduce disturbance without changing geometry, boundary
conditions or loading conditions. Asymmetric meshing affects both
predicted buckling load and buckling mode shapes. Cylindrical shell
having lay-up orientation [0^o/+45^o/-45^o/0^o] with radius to thickness
ratio (R/t) equal to 265 and length to radius ratio (L/R) equal to 1.5 is
analysed numerically. A series of numerical simulations
(experiments) are carried out with symmetric and asymmetric
meshing to study the effect of asymmetric meshing on predicted
buckling behaviour. Asymmetric meshing technique is employed in
both axial direction and circumferential direction separately using
two different methods, first by changing the shell element size and
varying the total number elements, and second by varying the shell
element size and keeping total number of elements constant. The
results of linear analysis (Eigenvalue analysis) and non-linear
analysis (Riks analysis) using symmetric meshing agree well with
analytical results. The results of numerical analysis are presented in
form of non-dimensional load factor, which is the ratio of buckling
load using asymmetric meshing technique to buckling load using
symmetric meshing technique. Using AMT, load factor has about 2%
variation for linear eigenvalue analysis and about 2% variation for
non-linear Riks analysis. The behaviour of load end-shortening curve
for pre-buckling is same for both symmetric and asymmetric meshing
but for asymmetric meshing curve behaviour in post-buckling
becomes extraordinarily complex. The major conclusions are:
different methods of AMT have small influence on predicted
buckling load and significant influence on load displacement curve
behaviour in post buckling; AMT in axial direction and AMT in
circumferential direction have different influence on buckling load
and load displacement curve in post-buckling.
Abstract: The present work aims to throw light on the effects of
arcing in air on the surface state of contact pastilles made of silvernickel
Ag-Ni (60/40). Also, the photoelectric emission from these
electrical contacts has been investigated in the spectral range of 196-
256 nm. In order to study the effects of arcing on the EWF, the
metallic samples were subjected to electrical arcs in air, at
atmospheric pressure and room temperature, after that, they have
been introduced into the vacuum chamber of an experimental UHV
set-up for EWF measurements. Both Fowler method of isothermal
curves and linearized Fowler plots were used for the measurement of
the EWF by the photoelectric effect.
It has been found that the EWF varies with the number of applied
arcs. Thus, after 500 arcs in air, the observed EWF increasing is
probably due to progressive inclusion of oxide on alloy surface.
Microscopic examination is necessary to get better understandings on
EWF of silver alloys, for both virgin and arced electrical contacts.
Abstract: Image search engines rely on the surrounding textual
keywords for the retrieval of images. It is a tedious work for the
search engines like Google and Bing to interpret the user’s search
intention and to provide the desired results. The recent researches
also state that the Google image search engines do not work well on
all the images. Consequently, this leads to the emergence of efficient
image retrieval technique, which interprets the user’s search intention
and shows the desired results. In order to accomplish this task, an
efficient image re-ranking framework is required. Sequentially, to
provide best image retrieval, the new image re-ranking framework is
experimented in this paper. The implemented new image re-ranking
framework provides best image retrieval from the image dataset by
making use of re-ranking of retrieved images that is based on the
user’s desired images. This is experimented in two sections. One is
offline section and other is online section. In offline section, the reranking
framework studies differently (reference classes or Semantic
Spaces) for diverse user query keywords. The semantic signatures get
generated by combining the textual and visual features of the images.
In the online section, images are re-ranked by comparing the
semantic signatures that are obtained from the reference classes with
the user specified image query keywords. This re-ranking
methodology will increases the retrieval image efficiency and the
result will be effective to the user.
Abstract: This study is used as a definition method to the value
and function in manufacturing sector. In concurrence of discussion
about present condition of modeling method, until now definition of
1D-CAE is ambiguity and not conceptual. Across all the physic fields,
those methods are defined with the formulation of differential
algebraic equation which only applied time derivation and simulation.
At the same time, we propose semi-acausal modeling concept and
differential algebraic equation method as a newly modeling method
which the efficiency has been verified through the comparison of
numerical analysis result between the semi-acausal modeling
calculation and FEM theory calculation.
Abstract: The study of organisations’ information security
cultures has attracted scholars as well as healthcare services industry
to research the topic and find appropriate tools and approaches to
develop a positive culture. The vast majority of studies in Saudi
national health services are on the use of technology to protect and
secure health services information. On the other hand, there is a lack
of research on the role and impact of an organisation’s cultural
dimensions on information security. This research investigated and
analysed the role and impact of cultural dimensions on information
security in Saudi Arabia health service. Hypotheses were tested and
two surveys were carried out in order to collect data and information
from three major hospitals in Saudi Arabia (SA). The first survey
identified the main cultural-dimension problems in SA health
services and developed an initial information security culture
framework model. The second survey evaluated and tested the
developed framework model to test its usefulness, reliability and
applicability. The model is based on human behaviour theory, where
the individual’s attitude is the key element of the individual’s
intention to behave as well as of his or her actual behaviour. The
research identified a set of cultural and sub-cultural dimensions in SA
health information security and services.
Abstract: High Peak to Average Power Ratio (PAPR) of the
transmitted signal is a serious problem in multicarrier systems (MC),
such as Orthogonal Frequency Division Multiplexing (OFDM), or in
Multi-Carrier Code Division Multiple Access (MC-CDMA) systems,
due to large number of subcarriers. This effect is possible reduce with
some PAPR reduction techniques. Spreading sequences at the
presence of Saleh and Rapp models of high power amplifier (HPA)
have big influence on the behavior of system. In this paper we
investigate the bit-error-rate (BER) performance of MC-CDMA
systems. Basically we can see from simulations that the MC-CDMA
system with Iterative algorithm can be providing significantly better
results than the MC-CDMA system. The results of our analyses are
verified via simulation.
Abstract: The paper deals with the usage of speech acts and
politeness strategies in an EFL classroom in Georgia (Rep of). It
explores the students’ and the teachers’ practice of the politeness
strategies and the speech acts of apology, thanking, request,
compliment / encouragement, command, agreeing / disagreeing,
addressing and code switching. The research method includes
observation as well as a questionnaire. The target group involves the
students from Georgian public schools and two certified, experienced
local English teachers. The analysis is based on Searle’s Speech Act
Theory and Brown and Levinson’s politeness strategies. The findings
show that the students have certain knowledge regarding politeness
yet they fail to apply them in English communication. In addition,
most of the speech acts from the classroom interaction are used by
the teachers and not the students. Thereby, it is suggested that
teachers should cultivate the students’ communicative competence
and attempt to give them opportunities to practise more English
speech acts than they do today.
Abstract: The adsorption efficiency of fired clayey pellets of 5
and 8 mm diameter size for Cu(II) and Zn(II) ion removal from a
waste printing developer was studied. In order to investigate the
influence of contact time, adsorbent mass and pellet size on the
adsorption efficiency the batch mode was carried out. Faster uptake
of copper ion was obtained with the fired clay pellets of 5 mm
diameter size within 30 minutes. The pellets of 8 mm diameter size
showed the higher equilibrium time (60 to 75 minutes) for copper and
zinc ion. The results pointed out that adsorption efficiency increases
with the increase of adsorbent mass. The maximal efficiency is
different for Cu(II) and Zn(II) ion due to the pellet size. Therefore,
the fired clay pellets of 5 mm diameter size present an effective
adsorbent for Cu(II) ion removal (adsorption efficiency is 63.6%),
whereas the fired clay pellets of 8 mm diameter size are the best
alternative for Zn(II) ion removal (adsorption efficiency is 92.8%)
from a waste printing developer.
Abstract: Background: With the perceived pain and poor
function experienced following knee arthroplasty, patients usually
feel un-satisfied. Yet, a controversy still persists on the appropriate
operative technique that doesn’t affect proprioception much.
Purpose: This study compared the effects of Cruciate Retaining
(CR) and Posterior Stabilized (PS) total knee arthroplasty (TKA on
dynamic balance, pain and functional performance following
rehabilitation.
Methods: Thirty patients with CRTKA (group I), thirty with
PSTKA (group II) and fifteen indicated for arthroplasty but weren’t
operated on yet (group III) participated in the study. The mean age
was 54.53±3.44, 55.13±3.48 and 55.33±2.32 years and BMI
35.7±3.03, 35.7±1.99 and 35.73±1.03 kg/m2 for groups I, II and III
respectively. The Berg Balance Scale (BBS), WOMAC pain subscale
and Timed Up-and-Go (TUG) and Stair-Climbing (SC) tests were
used for assessment. Assessments were conducted four weeks preand
post-operatively, three, six and twelve months post-operatively
with the control group being assessed at the same time intervals. The
post-operative rehabilitation involved hospitalization (1st week),
home-based (2nd-4th weeks), and outpatient clinic (5th-12th weeks)
programs, follow-up to all groups for twelve months.
Results: The Mixed design MANOVA revealed that group I had
significantly lower pain scores and SC time compared with group II
three, six and twelve months post-operatively. Moreover, the BBS
scores increased significantly and the pain scores and TUG and SC
time decreased significantly six months post-operatively compared
with four weeks pre- and post-operatively and three months postoperatively
in groups I and II with the opposite being true four weeks
post-operatively. But no significant differences in BBS scores, pain
scores and TUG and SC time between six and twelve months postoperatively
in groups I and II.
Interpretation/Conclusion: CRTKA is preferable to PSTKA,
possibly due to the preserved human proprioceptors in the un-excised
PCL.
Abstract: The main objective of this paper is study the influence
of carbon nano-tubes fibers and nano silica fibers on the
characteristic compressive strength and flexural strength on concrete
and cement mortar. Twelve tested specimens were tested with square
section its dimensions (4040 160) mm, divided into four groups.
The first and second group studied the effect of carbon nano-tubes
(CNTs) fibers with different percentage equal to 0.0, 0.11%, 0.22%,
and 0.33% by weight of cement and effect of nano-silica (nS) fibers
with different percentages equal to 0.0, 1.0%, 2.0%, and 3.0% by
weight of cement on the cement mortar. The third and fourth groups
studied the effect of CNTs fiber with different percentage equal to
0.0%, 0.11%, and 0.22% by weight of cement, and effect of nS fibers
with different percentages were equal to 0.0%, 1.0%, and 2.0% by
weight of cement on the concrete. The compressive strength and
flexural strength at 7, 28, and 90 days is determined. From analysis of
tested results concluded that the nano-fibers is more effective when
used with cement mortar more than used with concrete because of
increasing the surface area, decreasing the pore and the collection of
nano-fibers. And also by adding nano-fibers the improvement of
flexural strength of concrete and cement mortar is more than
improvement of compressive strength.
Abstract: In this study, composites were fabricated from oil
palm empty fruit bunch fiber and poly(lactic) acid by extrusion
followed by injection moulding. Surface of the fiber was pre-treated
by ultrasound in an alkali medium and treatment efficiency was
investigated by scanning electron microscopy (SEM) analysis and
Fourier transforms infrared spectrometer (FTIR). Effect of fiber
treatment on composite was characterized by tensile strength (TS),
tensile modulus (TM) and impact strength (IS). Furthermore,
biostrong impact modifier was incorporated into the treated fiber
composite to improve its impact properties. Mechanical testing
showed an improvement of up to 23.5% and 33.6% respectively for
TS and TM of treated fiber composite above untreated fiber
composite. On the other hand incorporation of impact modifier led to
enhancement of about 20% above the initial IS of the treated fiber
composite.
Abstract: The current study investigated the influence of milling
time and ball-to-powder (BPR) weight ratio on the microstructural
constituents and mechanical properties of bulk nanocrystalline Al;
Al-10%Cu; and Al-10%Cu-5%Ti alloys. Powder consolidation was
carried out using a high frequency induction heat sintering where the
processed metal powders were sintered into a dense and strong bulk
material. The powders and the bulk samples were characterized using
XRD and FEGSEM techniques. The mechanical properties were
evaluated at various temperatures of 25°C, 100°C, 200°C, 300°C and
400°C to study the thermal stability of the processed alloys. The
processed bulk nanocrystalline alloys displayed extremely high
hardness values even at elevated temperatures. The Al-10%Cu-5%Ti
alloy displayed the highest hardness values at room and elevated
temperatures which are related to the presence of Ti-containing
phases such as Al3Ti and AlCu2Ti. These phases are thermally stable
and retain the high hardness values at elevated temperatures up to
400ºC.
Abstract: The present study was undertaken to investigate the
effect of pre-aging and aging parameters (time and temperature) on
the mechanical properties of Al-Mg-Zn (7075) alloys. Ultimate
tensile strength, 0.5% offset yield strength and % elongation
measurements were carried out on specimens prepared from cast and
heat treated 7075 alloys. Aging treatments were carried out for the as
solution treated (SHT) specimens (after quenching in warm water).
The specimens were aged at different conditions; Natural aging was
carried out at room temperature for different periods of time. Double
aging was performed for SHT conditions (pre-aged at different time
and temperature followed by high temperature aging). Ultimate
tensile strength, yield strength and % elongation as a function of
different pre-aging and aging parameters are analyzed to acquire an
understanding of the effects of these variables and their interactions
on the mechanical properties of Be-treated 7075 alloys.
Abstract: Parameters of flow are calculated in vaneless diffusers
with relative width 0,014–0,10. Inlet angles of flow and similarity
criteria were varied. There is information on flow separation,
boundary layer development, configuration of streamlines.
Polytrophic efficiency, loss coefficient and recovery coefficient are
used to compare effectiveness of diffusers. The sample of
optimization of narrow diffuser with conical walls is presented. Three
wide diffusers with narrowing walls are compared. The work is made
in the R&D laboratory “Gas dynamics of turbo machines” of the TU
SPb.
Abstract: In this paper we consider the rule reduct generation
problem. Rule Reduct Generation (RG) and Modified Rule
Generation (MRG) algorithms, that are used to solve this problem,
are well-known. Alternative to these algorithms, we develop Pruning
Rule Generation (PRG) algorithm. We compare the PRG algorithm
with RG and MRG.