Abstract: This study offers a comprehensive review of the
research papers published in the field of cooling towers and gives an
insight into the latest developments of the natural draught cooling
towers. Different modeling, analysis and design techniques are
summarized and the challenges are discussed. The 118 references
included in this paper are mostly concentrated on the review of the
published papers after 2005. The present paper represents a complete
collection of the studies done for cooling towers and would give an
updated material for the researchers and design engineers in the field
of hyperbolic cooling towers.
Abstract: A computational fluid dynamics simulation is done for
non-Newtonian fluid in a baffled stirred tank. The CMC solution is
taken as non-Newtonian shear thinning fluid for simulation. The
Reynolds Average Navier Stocks equation with steady state multi
reference frame approach is used to simulate flow in the stirred tank.
The turbulent flow field is modelled using realizable k-ε turbulence
model. The simulated velocity profiles of Rushton turbine is
validated with literature data. Then, the simulated flow field of CD-6
impeller is compared with the Rushton turbine. The flow field
generated by CD-6 impeller is less in magnitude than the Rushton
turbine. The impeller global parameter, power number and flow
number, and entropy generation due to viscous dissipation rate is also
reported.
Abstract: Curcuma longa L. (Zingiberaceae), commonly known
as turmeric, has a long history of traditional uses for culinary
purposes as a spice and a food colorant. The present study aimed to
document the ethnobotanical knowledge about Curcuma longa, and
to assess the variation in the herbalists’ experience in Northeastern
Algeria. Data were collected using semi-structured questionnaires
and direct interviews with 30 herbalists. Ethnobotanical indices,
including the fidelity level (FL%), the relative frequency citation
(RFC), and use value (UV) were determined by quantitative methods.
Diversity in the level of knowledge was analyzed using univariate,
non-parametric, and multivariate statistical methods. Three main
categories of uses were recorded for C. longa: for food, for medicine,
and for cosmetic purposes. As a medicine, turmeric was used for the
treatment of gastrointestinal, dermatological, and hepatic diseases.
Medicinal and food uses were correlated with both forms of
preparation (rhizome and powder). The age group did not influence
the use. Multivariate analyses showed a significant variation in
traditional knowledge, associated with the use value, origin, quality,
and efficacy of the drug. The findings suggested that the geographical
origin of C. longa affected the use in Algeria.
Abstract: The handwriting is a physical demonstration of a
complex cognitive process learnt by man since his childhood. People
with disabilities or suffering from various neurological diseases are
facing so many difficulties resulting from problems located at the
muscle stimuli (EMG) or signals from the brain (EEG) and which
arise at the stage of writing. The handwriting velocity of the same
writer or different writers varies according to different criteria: age,
attitude, mood, writing surface, etc. Therefore, it is interesting to
reconstruct an experimental basis records taking, as primary
reference, the writing speed for different writers which would allow
studying the global system during handwriting process. This paper
deals with a new approach of the handwriting system modeling based
on the velocity criterion through the concepts of artificial neural
networks, precisely the Radial Basis Functions (RBF) neural
networks. The obtained simulation results show a satisfactory
agreement between responses of the developed neural model and the
experimental data for various letters and forms then the efficiency of
the proposed approaches.
Abstract: At-site flood frequency analysis is used to estimate
flood quantiles when at-site record length is reasonably long. In
Australia, FLIKE software has been introduced for at-site flood
frequency analysis. The advantage of FLIKE is that, for a given
application, the user can compare a number of most commonly
adopted probability distributions and parameter estimation methods
relatively quickly using a windows interface. The new version of
FLIKE has been incorporated with the multiple Grubbs and Beck test
which can identify multiple numbers of potentially influential low
flows. This paper presents a case study considering six catchments in
eastern Australia which compares two outlier identification tests
(original Grubbs and Beck test and multiple Grubbs and Beck test)
and two commonly applied probability distributions (Generalized
Extreme Value (GEV) and Log Pearson type 3 (LP3)) using FLIKE
software. It has been found that the multiple Grubbs and Beck test
when used with LP3 distribution provides more accurate flood
quantile estimates than when LP3 distribution is used with the
original Grubbs and Beck test. Between these two methods, the
differences in flood quantile estimates have been found to be up to
61% for the six study catchments. It has also been found that GEV
distribution (with L moments) and LP3 distribution with the multiple
Grubbs and Beck test provide quite similar results in most of the
cases; however, a difference up to 38% has been noted for flood
quantiles for annual exceedance probability (AEP) of 1 in 100 for one
catchment. This finding needs to be confirmed with a greater number
of stations across other Australian states.
Abstract: An investigation into the effect of countersunk depth,
plate thickness, countersunk angle and plate width on the stress
concentration around countersunk hole is carried out with the help of
finite element analysis. The variation of stress concentration with
respect to these parameters is studied for three types of loading viz.
uniformly distributed load, uniformly varying load and functionally
distributed load. The results of the finite element analysis are
interpreted and some conclusions are drawn. The distribution of
stress concentration around countersunk hole in isotropic plates
simply supported at all the edges is found similar and is independent
of loading. The maximum stress concentration also occurs at a
particular point irrespective of the loading conditions.
Abstract: Present study is aimed on the cutting process of circular
cross-section rods where the fracture is used to separate one rod
into two pieces. Incorporating the phenomenological ductile fracture
model into the explicit formulation of finite element method, the
process can be analyzed without the necessity of realizing too many
real experiments which could be expensive in case of repetitive
testing in different conditions. In the present paper, the steel AISI
1045 was examined and the tensile tests of smooth and notched
cylindrical bars were conducted together with biaxial testing of the
notched tube specimens to calibrate material constants of selected
phenomenological ductile fracture models. These were implemented
into the Abaqus/Explicit through user subroutine VUMAT and used
for cutting process simulation. As the calibration process is based
on variables which cannot be obtained directly from experiments,
numerical simulations of fracture tests are inevitable part of the
calibration. Finally, experiments regarding the cutting process were
carried out and predictive capability of selected fracture models is
discussed. Concluding remarks then make the summary of gained
experience both with the calibration and application of particular
ductile fracture criteria.
Abstract: Self-service technologies (SSTs) make an important
contribution to the daily life of people nowadays. However, the
introduction of SST does not lead to its usage. Thereby, this paper
was an attempt on discovery of the most preferred SST in the
customers’ point of view. To fulfill this aim, the Analytical Hierarchy
Process (AHP) was applied based on Saaty’s questionnaire which
was administered to the customers of e-banking services located in
Golestan providence, northern Iran. This study used qualitative
factors in association with the intention of consumers’ usage of SSTs
to rank three SSTs: ATM, mobile banking and internet banking. The
results showed that mobile banking get the highest weight in
consumers’ point of view. This research can be useful both for
managers and service providers and also for customers who intend to
use e-banking.
Abstract: Drying behavior of blanched sweet potato in a cabinet
dryer using different five air temperatures (40-80°C) and ten sweet
potato varieties sliced to 5mm thickness were investigated. The
drying data were fitted to eight models. The Modified Henderson and
Pabis model gave the best fit to the experimental moisture ratio data
obtained during the drying of all the varieties while Newton (Lewis)
and Wang and Singh models gave the least fit. The values of Deff
obtained for Bophelo variety (1.27 x 10-9 to 1.77 x 10-9 m2/s) was
the least while that of S191 (1.93 x 10-9 to 2.47 x 10-9 m2/s) was the
highest which indicates that moisture diffusivity in sweet potato is
affected by the genetic factor. Activation energy values ranged from
0.27-6.54 kJ/mol. The lower activation energy indicates that drying
of sweet potato slices requires less energy and is hence a cost and
energy saving method. The drying behavior of blanched sweet potato
was investigated in a cabinet dryer. Drying time decreased
considerably with increase in hot air temperature. Out of the eight
models fitted, the Modified Henderson and Pabis model gave the best
fit to the experimental moisture ratio data on all the varieties while
Newton, Wang and Singh models gave the least. The lower activation
energy (0.27 - 6.54 kJ/mol) obtained indicates that drying of sweet
potato slices requires less energy and is hence a cost and energy
saving method.
Abstract: In today’s world, the LED display has been used for
presenting visual information under various circumstances. Such
information is an important intermediary in the human information
processing. Researchers have been investigated diverse factors that
influence this process effectiveness. The letter size is undoubtedly
one major factor that has been tested and recommended by many
standards and guidelines. However, viewing information on the
display from direct perpendicular position is a typical assumption
whereas many actual events are required viewing from the angles.
This current research aims to study the effect of oblique viewing
angle and viewing distance on ability to recognize alphabet, number,
and English word. The total of ten participants was volunteered to our
3 x 4 x 4 within subject study. Independent variables include three
distance levels (2, 6, and 12 m), four oblique angles (0, 45, 60, 75
degree), and four target types (alphabet, number, short word, and
long word). Following the method of constant stimuli our study
suggests that the larger oblique angle, ranging from 0 to 75 degree
from the line of sight, results in significant higher legibility threshold
or larger font size required (p-value < 0.05). Viewing distance factor
also shows to have significant effect on the threshold (p-value
Abstract: In this study, we aim to demonstrate a microgrid
system experimental simulation for an easy understanding of a
large-scale microgrid system. This model is required for industrial
training and learning environments. However, in order to create an
exact representation of a microgrid system, the laboratory-scale
system must fulfill the requirements of a grid-connected inverter, in
which power values are assigned to the system to cope with the
intermittent output from renewable energy sources. Aside from that,
during fluctuations in load capacity, the grid-connected system must
be able to supply power from the utility grid side and microgrid side in
a balanced manner. Therefore, droop control is installed in the
inverter’s control board to maintain a balanced power sharing in both
sides. This power control in a stand-alone condition and droop control
in a grid-connected condition must be implemented in order to
maintain a stabilized system. Based on the experimental results, power
control and droop control can both be applied in the system by
comparing the experimental and reference values.
Abstract: GRF, Growth regulating factor, genes encode a novel
class of plant-specific transcription factors. The GRF proteins play a
role in the regulation of cell numbers in young and growing tissues
and may act as transcription activations in growth and development
of plants. Identification of GRF genes and their expression are
important in plants to performance of the growth and development of
various organs. In this study, to better understanding the structural
and functional differences of GRFs family, 45 GRF proteins
sequences in A. thaliana, Z. mays, O. sativa, B. napus, B. rapa, H.
vulgare and S. bicolor, have been collected and analyzed through
bioinformatics data mining. As a result, in secondary structure of
GRFs, the number of alpha helices was more than beta sheets and in
all of them QLQ domains were completely in the biggest alpha helix.
In all GRFs, QLQ and WRC domains were completely protected
except in AtGRF9. These proteins have no trans-membrane domain
and due to have nuclear localization signals act in nuclear and they
are component of unstable proteins in the test tube.
Abstract: The substantial similarity of fatigue mechanism in a
new test rig for rolling contact fatigue (RCF) has been investigated. A
new reduced-scale test rig is designed to perform controlled RCF
tests in wheel-rail materials. The fatigue mechanism of the rig is
evaluated in this study using a combined finite element-fatigue
prediction approach. The influences of loading conditions on fatigue
crack initiation have been studied. Furthermore, the effects of some
artificial defects (squat-shape) on fatigue lives are examined. To
simulate the vehicle-track interaction by means of the test rig, a threedimensional
finite element (FE) model is built up. The nonlinear
material behaviour of the rail steel is modelled in the contact
interface. The results of FE simulations are combined with the critical
plane concept to determine the material points with the greatest
possibility of fatigue failure. Based on the stress-strain responses, by
employing of previously postulated criteria for fatigue crack initiation
(plastic shakedown and ratchetting), fatigue life analysis is carried
out. The results are reported for various loading conditions and
different defect sizes. Afterward, the cyclic mechanism of the test rig
is evaluated from the operational viewpoint. The results of fatigue
life predictions are compared with the expected number of cycles of
the test rig by its cyclic nature. Finally, the estimative duration of the
experiments until fatigue crack initiation is roughly determined.
Abstract: A new small–scale test rig developed for rolling
contact fatigue (RCF) investigations in wheel–rail material. This
paper presents the scaling strategy of the rig based on dimensional
analysis and mechanical modelling. The new experimental rig is
indeed a spinning frame structure with multiple wheel components
over a fixed rail-track ring, capable of simulating continuous wheelrail
contact in a laboratory scale. This paper describes the
dimensional design of the rig, to derive its overall scaling strategy
and to determine the key elements’ specifications. Finite element
(FE) modelling is used to simulate the mechanical behavior of the rig
with two sample scale factors of 1/5 and 1/7. The results of FE
models are compared with the actual railway system to observe the
effectiveness of the chosen scales. The mechanical properties of the
components and variables of the system are finally determined
through the design process.
Abstract: This study is purposed to develop an efficient fault
detection method for Global Navigation Satellite Systems (GNSS)
applications based on adaptive noise covariance estimation. Due to the
dependence on radio frequency signals, GNSS measurements are
dominated by systematic errors in receiver’s operating environment.
In the proposed method, the pseudorange and carrier-phase
measurement noise covariances are obtained at time propagations and
measurement updates in process of Carrier-Smoothed Code (CSC)
filtering, respectively. The test statistics for fault detection are
generated by the estimated measurement noise covariances. To
evaluate the fault detection capability, intentional faults were added to
the filed-collected measurements. The experiment result shows that
the proposed method is efficient in detecting unhealthy measurements
and improves GNSS positioning accuracy against fault occurrences.
Abstract: One of the most important tasks in the risk
management is the correct determination of probability of default
(PD) of particular financial subjects. In this paper a possibility of
determination of financial institution’s PD according to the creditscoring
models is discussed. The paper is divided into the two parts.
The first part is devoted to the estimation of the three different
models (based on the linear discriminant analysis, logit regression
and probit regression) from the sample of almost three hundred US
commercial banks. Afterwards these models are compared and
verified on the control sample with the view to choose the best one.
The second part of the paper is aimed at the application of the chosen
model on the portfolio of three key Czech banks to estimate their
present financial stability. However, it is not less important to be able
to estimate the evolution of PD in the future. For this reason, the
second task in this paper is to estimate the probability distribution of
the future PD for the Czech banks. So, there are sampled randomly
the values of particular indicators and estimated the PDs’ distribution,
while it’s assumed that the indicators are distributed according to the
multidimensional subordinated Lévy model (Variance Gamma model
and Normal Inverse Gaussian model, particularly). Although the
obtained results show that all banks are relatively healthy, there is
still high chance that “a financial crisis” will occur, at least in terms
of probability. This is indicated by estimation of the various quantiles
in the estimated distributions. Finally, it should be noted that the
applicability of the estimated model (with respect to the used data) is
limited to the recessionary phase of the financial market.
Abstract: This paper present the experimental work of double
unit tunnel form building (TFB) subjected to in-plane lateral cyclic
loading. A one third scale of 3-storey double unit of TFB is tested
until its strength degradation. Then, the TFB is repaired and
retrofitted using additional shear wall, steel angle and CFRP sheet.
The crack patterns, lateral strength, stiffness, ductility and equivalent
viscous damping (EVD) were analyzed and compared before and
after repair and retrofit. The result indicates that the lateral strength
increases by 22% in pushing and 27% in pulling direction. Moreover,
the stiffness and ductility obtained before and after retrofit increase
tremendously by 87.87% and 39.66%, respectively. Meanwhile, the
energy absorption measured by equivalent viscous damping obtained
after retrofit increase by 12.34% in pulling direction. It can be
concluded that the proposed retrofit method is capable to increase the
lateral strength capacity, stiffness and energy absorption of double
unit TFB.
Abstract: The crude oil in an oil well exists in various phases
such as gas, seawater, and sand, as well as oil. Therefore, a phase
separator is needed at the front of a single-phase pump for
pressurization and transfer. On the other hand, the application of a
multiphase pump can provide such advantages as simplification of the
equipment structure and cost savings, because there is no need for a
phase separation process. Therefore, the crude oil transfer method
using a multiphase pump is being applied to recently developed oil
wells. Due to this increase in demand, technical demands for the
development of multiphase pumps are sharply increasing, but the
progress of research into related technologies is insufficient, due to the
nature of multiphase pumps that require high levels of skills. This
study was conducted to verify the reliability of pump performance
evaluation using numerical analysis, which is the basis of the
development of a multiphase pump. For this study, a model was
designed by selecting the specifications of this study. The performance
of the designed model was evaluated through numerical analysis and
experiment. The results of the performance evaluation were compared
to verify the reliability of the result using numerical analysis.
Abstract: One of the biggest challenges facing Theological/
Religious Education in Nigeria is access to quality learning materials.
For instance at the Trinity (Union) Theological College, Umuahia, it
was difficult for lecturers to access suitable and qualitative materials
for instruction especially the ones that would suit the African context
and stimulate a deep rooted interest among the students. Some
textbooks written by foreign authors were readily available in the
School Library, but were lacking in the College bookshops for
students to own copies. Even when the College was able to order
some of the books from abroad, it did not usher in the needed
enthusiasm expected from the students because they were either very
expensive or very difficult to understand during private studies. So it
became necessary to develop contextual materials which were
affordable and understandable, though with little success. The
National Open University of Nigeria (NOUN)’s innovation in the
development and sharing of learning resources through its Open
Courseware is a welcome development and of great assistance to
students. Apart from NOUN students who could easily access the
materials, many others from various theological/religious institutes
across the nation have benefited immensely. So, the thesis of this
paper is that the promotion of open educational resources in
theological/religious education in Nigeria would facilitate a better
informed/equipped religious leadership, which would in turn impact
its adherents for a healthier society and national development.
Adopting a narrative and historical approach within the context of
Nigeria’s educational system, the paper discusses: educational
traditions in Nigeria; challenges facing theological/religious
education in Nigeria; and benefits of open educational resources. The
study goes further to making recommendations on how OER could
positively influence theological/religious education in Nigeria. It is
expected that theologians, religious educators, and ODL practitioners
would find this work very useful.
Abstract: In structures, stress concentration is a factor of fatigue
fracture. Basically, the stress concentration is a phenomenon that
should be avoided. However, it is difficult to avoid the stress
concentration. Therefore, relaxation of the stress concentration is
important. The stress concentration arises from notches and circular
holes. There is a relaxation method that a composite patch covers a
notch and a circular hole. This relaxation method is used to repair
aerial wings, but it is not systematized. Composites are more
expensive than single materials. Accordingly, we propose the
relaxation method that a single material patch covers a notch and a
circular hole, and aim to systematize this relaxation method.
We performed FEA (Finite Element Analysis) about an object by
using a three-dimensional FEA model. The object was that a patch
adheres to a plate with a circular hole. And, a uniaxial tensile load acts
on the patched plate with a circular hole. In the three-dimensional FEA
model, it is not easy to model the adhesion layer. Basically, the yield
stress of the adhesive is smaller than that of adherents. Accordingly,
the adhesion layer gets to plastic deformation earlier than the adherents
under the yield load of adherents. Therefore, we propose the
three-dimensional FEA model which is applied a nonlinear elastic
region to the adhesion layer. The nonlinear elastic region was
calculated by a bilinear approximation. We compared the analysis
results with the tensile test results to confirm whether the analysis
model has usefulness. As a result, the analysis results agreed with the
tensile test results. And, we confirmed that the analysis model has
usefulness.
As a result that the three-dimensional FEA model was used to the
analysis, it was confirmed that an out-of-plane deformation occurred
to the patched plate with a circular hole. The out-of-plane deformation
causes stress increase of the patched plate with a circular hole.
Therefore, we investigated that the out-of-plane deformation affects
relaxation of the stress concentration in the plate with a circular hole
on this relaxation method. As a result, it was confirmed that the
out-of-plane deformation inhibits relaxation of the stress concentration
on the plate with a circular hole.