Abstract: This paper presents a model predictive control (MPC)
of a utility interactive three phase inverter (TPI) for a photovoltaic
(PV) system at commercial level. The proposed model uses phase
locked loop (PLL) to synchronize the TPI with the power electric
grid (PEG) and performs MPC control in a dq reference frame. TPI
model consists of a boost converter (BC), maximum power point
tracking (MPPT) control, and a three-leg voltage source inverter
(VSI). The operational model of VSI is used to synthesize the
sinusoidal current and track the reference. The model is validated
using a 35.7 kW PV system in Matlab/Simulink. Implementation
results show simplicity and accuracy, as well as reliability of the
model.
Abstract: The use of information technology in education have
changed not only the learners learning style but also the way they
taught, where nowadays learners are connected with diversity of
information sources with means of knowledge available everywhere.
The advantage of network wireless technologies and mobility
technologies used in the education and learning processes lead to
mobile learning as a new model of learning technology. Currently,
most of mobile learning applications are developed for the formal
education and learning environment. Despite the long history and
large amount of research on mobile learning and instruction design
model still there is a need of well-defined process in designing
mobile learning applications. Based on this situation, this paper
emphasizes on identifying instruction design phase’s considerations
and influencing factors in developing mobile learning application.
This set of instruction design steps includes analysis, design,
development, implementation, evaluation and continuous has been
built from a literature study, with focus on standards for learning,
mobile application software quality and guidelines. The effort is part
of an Omani-funded research project investigating the development,
adoption and dissemination of mobile learning in Oman.
Abstract: This paper presents comparative analysis of
photovoltaic systems (PVS) and propose practical techniques to
improve operational efficiency of the PVS. The best engineering and
construction practices for PVS are identified and field oriented
recommendation are made. Comparative analysis of central and
string inverter based, as well as 600 and 1000VDC PVS are
performed. In addition, direct current (DC) and alternating current
(AC) photovoltaic (PV) module based systems are compared.
Comparison shows that 1000V DC String Inverters based PVS is the
best choice.
Abstract: This paper considers the design of Dual Proportional-
Integral (DPI) Load Frequency Control (LFC), using gravitational
search algorithm (GSA). The design is carried out for nonlinear
hydrothermal power system where generation rate constraint (GRC)
and governor dead band are considered. Furthermore, time delays
imposed by governor-turbine, thermodynamic process, and
communication channels are investigated. GSA is utilized to search
for optimal controller parameters by minimizing a time-domain based
objective function. GSA-based DPI has been compared to Ziegler-
Nichols based PI, and Genetic Algorithm (GA) based PI controllers
in order to demonstrate the superior efficiency of the proposed
design. Simulation results are carried for a wide range of operating
conditions and system parameters variations.
Abstract: Tamil handwritten document is taken as a key source
of data to identify the writer. Tamil is a classical language which has
247 characters include compound characters, consonants, vowels and
special character. Most characters of Tamil are multifaceted in
nature. Handwriting is a unique feature of an individual. Writer may
change their handwritings according to their frame of mind and this
place a risky challenge in identifying the writer. A new
discriminative model with pooled features of handwriting is proposed
and implemented using support vector machine. It has been reported
on 100% of prediction accuracy by RBF and polynomial kernel based
classification model.
Abstract: Tamil handwritten document is taken as a key source of data to identify the writer. Tamil is a classical language which has 247 characters include compound characters, consonants, vowels and special character. Most characters of Tamil are multifaceted in nature. Handwriting is a unique feature of an individual. Writer may change their handwritings according to their frame of mind and this place a risky challenge in identifying the writer. A new discriminative model with pooled features of handwriting is proposed and implemented using support vector machine. It has been reported on 100% of prediction accuracy by RBF and polynomial kernel based classification model.
Abstract: Water resource systems modeling has constantly been
a challenge through history for human beings. As the innovative
methodological development is evolving alongside computer sciences
on one hand, researches are likely to confront more complex and
larger water resources systems due to new challenges regarding
increased water demands, climate change and human interventions,
socio-economic concerns, and environment protection and
sustainability. In this research, an automatic calibration scheme has
been applied on the Gilan’s large-scale water resource model using
mathematical programming. The water resource model’s calibration
is developed in order to attune unknown water return flows from
demand sites in the complex Sefidroud irrigation network and other
related areas. The calibration procedure is validated by comparing
several gauged river outflows from the system in the past with model
results. The calibration results are pleasantly reasonable presenting a
rational insight of the system. Subsequently, the unknown optimized
parameters were used in a basin-scale linear optimization model with
the ability to evaluate the system’s performance against a reduced
inflow scenario in future. Results showed an acceptable match
between predicted and observed outflows from the system at selected
hydrometric stations. Moreover, an efficient operating policy was
determined for Sefidroud dam leading to a minimum water shortage
in the reduced inflow scenario.
Abstract: A multilayer passive shield composed of low-activity
lead (Pb), copper (Cu), tin (Sn) and iron (Fe) was designed and
manufactured for a coaxial HPGe detector placed at a surface
laboratory for reducing background radiation and radiation dose to
the personnel. The performance of the shield was evaluated and
efficiency curves of the detector were plotted by using of various
standard sources in different distances. Monte Carlo simulations and
a set of TLD chips were used for dose estimation in two distances of
20 and 40 cm. The results show that the shield reduced background
spectrum and the personnel dose more than 95%.
Abstract: This study aimed to explore the practical experience
of child welfare caseworkers and professionalism in child case
management in Malaysia. This paper discussed the specific social
work practice competency and the challenges faced by child
caseworkers in the fieldwork. This research was qualitative with
grounded theory approach. Four sessions of focused group discussion
(FGD) were conducted involving a total of 27 caseworkers (child
protector and probation officers) in the Klang Valley. The study
found that the four basic principles of knowledge in child case
management namely: 1. knowledge in child case management; 2.
professional values of caseworkers towards children; 3. skills in
managing cases; and 4. culturally competent practice in child case
management. In addition, major challenges faced by the child case
manager are the capacity and commitment of the family in children’s
rehabilitation program, the credibility of caseworkers are being
challenged, and the challenges of support system from intra and interagency.
This study is important for policy makers to take into account
the capacity and the needs of the child’s caseworker in accordance
with the national social work competency framework. It is expected
that case management services for children will improve
systematically in line with national standards.
Abstract: Electrohydraulic servo system have been used in
industry in a wide number of applications. Its dynamics are highly
nonlinear and also have large extent of model uncertainties and
external disturbances. In this paper, a robust back-stepping control
(RBSC) scheme is proposed to overcome the problem of disturbances
and system uncertainties effectively and to improve the tracking
performance of EHS systems. In order to implement the proposed
control scheme, the system uncertainties in EHS systems are
considered as total leakage coefficient and effective oil volume. In
addition, in order to obtain the virtual controls for stabilizing system,
the update rule for the system uncertainty term is induced by
the Lyapunov control function (LCF). To verify the performance and
robustness of the proposed control system, computer simulation of
the proposed control system using Matlab/Simulink Software
is executed. From the computer simulation, it was found that the
RBSC system produces the desired tracking performance and has
robustness to the disturbances and system uncertainties of EHS
systems.
Abstract: This paper deals with nonlinear vibration analysis
using finite element method for frame structures consisting of elastic
and viscoelastic damping layers supported by multiple nonlinear
concentrated springs with hysteresis damping. The frame is supported
by four nonlinear concentrated springs near the four corners. The
restoring forces of the springs have cubic non-linearity and linear
component of the nonlinear springs has complex quantity to represent
linear hysteresis damping. The damping layer of the frame structures
has complex modulus of elasticity. Further, the discretized equations in
physical coordinate are transformed into the nonlinear ordinary
coupled differential equations using normal coordinate corresponding
to linear natural modes. Comparing shares of strain energy of the
elastic frame, the damping layer and the springs, we evaluate the
influences of the damping couplings on the linear and nonlinear impact
responses. We also investigate influences of damping changed by
stiffness of the elastic frame on the nonlinear coupling in the damped
impact responses.
Abstract: This paper discusses the propagation of sound waves in
air, specifically in narrow rectangular pathways of an occluded-ear
simulator for acoustic measurements. In narrow pathways, both the
speed of sound and the phase of the sound waves are affected by the
damping of the air viscosity. Herein, we propose a new finite-element
method (FEM) that considers the effects of the air viscosity. The
method was developed as an extension of existing FEMs for porous,
sound-absorbing materials. The results of a numerical calculation for a
three-dimensional ear-simulator model using the proposed FEM were
validated by comparing with theoretical lumped-parameter modeling
analysis and standard values.
Abstract: Effects of nicotine on pre-partum body weight and
preimplantation embryonic development has been reported
previously. Present study was conducted to determine the effects of
annatto (Bixa orellana)-derived delta-tocotrienol (TCT) (with
presence of 10% gamma-TCT isomer) on the nicotine-induced
reduction in body weight and 8-cell embryonic growth in mice.
Twenty-four 6-8 weeks old (23-25g) female balb/c mice were
randomly divided into four groups (G1-G4; n=6). Those groups were
subjected to the following treatments for 7 consecutive days: G1
(control) were gavaged with 0.1 ml tocopherol stripped corn oil. G2
was subcutaneously (s.c.) injected with 3 mg/kg/day of nicotine. G3
received concurrent treatment of nicotine (3 mg/kg/day) and 60
mg/kg/day of δ-TCT mixture (contains 90% delta & 10% gamma
isomers) and G4 was given 60 mg/kg/day of δ-TCT mixture alone.
Body weights were recorded daily during the treatment. On Day 8,
females were superovulated with 5 IU Pregnant Mare’s Serum
Gonadotropin (PMSG) for 48 hours followed with 5 IU human
Chorionic Gonadotropin (hCG) before mated with males at the ratio
of 1:1. Females were sacrificed by cervical dislocation for embryo
collection 48 hours post-coitum. Collected embryos were cultured in
vitro. Results showed that throughout Day 1 to Day 7, the body
weight of nicotine treated group (G2) was significantly lower
(p
Abstract: Industries produce millions of cubic meters of effluent
every year and the wastewater produced may be released into the
surrounding water bodies, treated on-site or at municipal treatment
plants. The determination of organic matter in the wastewater
generated is very important to avoid any negative effect on the
aquatic ecosystem. The scope of the present work is to assess the
physicochemical composition of the wastewater produced from one
of the brewery industry in South Africa. This is to estimate the
environmental impact of its discharge into the receiving water bodies
or the municipal treatment plant. The parameters monitored for the
quantitative analysis of brewery wastewater include biological
oxygen demand (BOD5), chemical oxygen demand (COD), total
suspended solids, volatile suspended solids, ammonia, total oxidized
nitrogen, nitrate, nitrite, phosphorus and alkalinity content. In
average, the COD concentration of the brewery effluent was 5340.97
mg/l with average pH values of 4.0 to 6.7. The BOD5 and the solids
content of the wastewater from the brewery industry were high. This
means that the effluent is very rich in organic content and its
discharge into the water bodies or the municipal treatment plant could
cause environmental pollution or damage the treatment plant. In
addition, there were variations in the wastewater composition
throughout the monitoring period. This might be as a result of
different activities that take place during the production process, as
well as the effects of peak period of beer production on the water
usage.
Abstract: To evaluate the vigor of wheat seeds and stress of
premature aging effects on germination percentage, root length and
shoot length of five wheat cultivars that include Vynak, Karkheh,
Chamran, Star and Kavir which underwent a period of zero, two,
three, four days in terms of premature aging with 41°C temperature
and 100% relative humidity. Seed germination percentage, root
length and shoot length in these conditions were measured. This
experiment was conducted as a factorial completely randomized
design with four replications in laboratory conditions. The results
showed that each of aging treatments used in this experiment can be
used to detect differences in vigor of wheat varieties. Wheat cultivars
illustrated significant differences in germination percentage, root
length and shoot length in terms of premature aging. The wheat
cultivars; Astar and Vynak had maximum germination percentage
and Karkheh, respectively Kavir and Chamran had lowest percentage
of seed germination. Reactions of root and shoot length of wheat
cultivars was also different. The results showed that the seeds with a
stronger vigor affected less in premature aging condition and the
difference between the percentage of seed germination under normal
conditions and stress was significant and the seeds with the weaker
vigor were more sensitive to the premature aging stress and the
premature aging had more severe negative impact on seed vigor.
Abstract: Particle size distribution, the most important
characteristics of aerosols, is obtained through electrical
characterization techniques. The dynamics of charged nanoparticles
under the influence of electric field in Electrical Mobility
Spectrometer (EMS) reveals the size distribution of these particles.
The accuracy of this measurement is influenced by flow conditions,
geometry, electric field and particle charging process, therefore by
the transfer function (transfer matrix) of the instrument. In this work,
a wire-cylinder corona charger was designed and the combined fielddiffusion
charging process of injected poly-disperse aerosol particles
was numerically simulated as a prerequisite for the study of a
multichannel EMS. The result, a cloud of particles with no uniform
charge distribution, was introduced to the EMS. The flow pattern and
electric field in the EMS were simulated using Computational Fluid
Dynamics (CFD) to obtain particle trajectories in the device and
therefore to calculate the reported signal by each electrometer.
According to the output signals (resulted from bombardment of
particles and transferring their charges as currents), we proposed a
modification to the size of detecting rings (which are connected to
electrometers) in order to evaluate particle size distributions more
accurately. Based on the capability of the system to transfer
information contents about size distribution of the injected particles,
we proposed a benchmark for the assessment of optimality of the
design. This method applies the concept of Von Neumann entropy
and borrows the definition of entropy from information theory
(Shannon entropy) to measure optimality. Entropy, according to the
Shannon entropy, is the ''average amount of information contained in
an event, sample or character extracted from a data stream''.
Evaluating the responses (signals) which were obtained via various
configurations of detecting rings, the best configuration which gave
the best predictions about the size distributions of injected particles,
was the modified configuration. It was also the one that had the
maximum amount of entropy. A reasonable consistency was also
observed between the accuracy of the predictions and the entropy
content of each configuration. In this method, entropy is extracted
from the transfer matrix of the instrument for each configuration.
Ultimately, various clouds of particles were introduced to the
simulations and predicted size distributions were compared to the
exact size distributions.
Abstract: In order to study the effect of different levels of triple
super phosphate chemical fertilizer and biological phosphate fertilizer
(fertile 2) on some morphological traits of corn this research was
carried out in Ahvaz in 2002 as a factorial experiment in randomized
complete block design with 4 replications). The experiment included
two factors: first, biological phosphate fertilizer (fertile 2) at three
levels of 0, 100, 200 g/ha; second, triple super phosphate chemical
fertilizer at three levels of 0, 60, 90 kg/ha of pure phosphorus (P2O5).
The obtained results indicated that fertilizer treatments had a
significant effect on some morphological traits at 1% probability
level. In this regard, P2B2 treatment (100 g/ha biological phosphate
fertilizer (fertile 2) and 60 kg/ha triple super phosphate fertilizer) had
the greatest plant height, stem diameter, number of leaves and ear
length. It seems that in Ahvaz weather conditions, decrease of
consumption of triple superphosphate chemical fertilizer to less than
a half along with the consumption of biological phosphate fertilizer
(fertile 2) is highly important in order to achieve optimal results.
Therefore, it can be concluded that biological fertilizers can be used
as a suitable substitute for some of the chemical fertilizers in
sustainable agricultural systems.
Abstract: The synthesis of CuFe2O4 spinel powders by an
optimized combustion-like process followed by calcination is
described herein. The samples were characterized using X-ray
diffraction (XRD), differential thermal analysis (TG/DTA), scanning
electron microscopy (SEM), dilatometry and 4-probe DC methods.
Different glycine to nitrate (G/N) ratios of 1 (fuel-deficient), 1.48
(stoichiometric) and 2 (fuel-rich) were employed. Calcining the asprepared
powders at 800 and 1000°C for 5 hours showed that the G/N
ratio of 2 results in the formation of the desired copper spinel single
phase at both calcination temperatures. For G/N=1, formation of
CuFe2O4 takes place in three steps. First, iron and copper nitrates
decompose to iron oxide and pure copper. Then, copper transforms to
copper oxide and finally, copper and iron oxides react with each other
to form a copper ferrite spinel phase. The electrical conductivity and
the coefficient of thermal expansion of the sintered pelletized
samples were 2 S.cm-1 (800°C) and 11×10-6 °C-1 (25-800°C),
respectively.
Abstract: Several embryonic cellular mechanism including cell
cycle, growth and apoptosis are regulated by phosphatidylinositol-3-
kinase (PI3K)/Akt signaling pathway. The goal of present study is to
determine the effects of annatto (Bixa orellana)-derived δ-tocotrienol
(δ-TCT) on the regulations of PI3K/Akt genes in murine morula.
Twenty four 6-8 week old (23-25g) female balb/c mice were
randomly divided into four groups (G1-G4; n=6). Those groups were
subjected to the following treatments for 7 consecutive days: G1
(control) received tocopherol stripped corn oil, G2 was given 60
mg/kg/day of δ-TCT mixture (contains 90% delta & 10% gamma
isomers), G3 was given 60 mg/kg/day of pure δ-TCT (>98% purity)
and G4 received 60 mg/kg/day α-TOC. On Day 8, females were
superovulated with 5 IU Pregnant Mare’s Serum Gonadotropin
(PMSG) for 48 hours followed with 5 IU human Chorionic
Gonadotropin (hCG) before mated with males at the ratio of 1:1.
Females were sacrificed by cervical dislocation for embryo collection
48 hours post-coitum. About fifty morulas from each group were
used in the gene expression analyses using Affymetrix QuantiGene
Plex 2.0 Assay. Present data showed a significant increase (p
Abstract: Ceramic Waste Aggregates (CWAs) were made from
electric porcelain insulator wastes supplied from an electric power
company, which were crushed and ground to fine aggregate sizes. In
this study, to develop the CWA mortar as an eco–efficient, ground
granulated blast–furnace slag (GGBS) as a Supplementary
Cementitious Material (SCM) was incorporated. The water–to–binder
ratio (W/B) of the CWA mortars was varied at 0.4, 0.5, and 0.6. The
cement of the CWA mortar was replaced by GGBS at 20 and 40% by
volume (at about 18 and 37% by weight). Mechanical properties of
compressive and splitting tensile strengths, and elastic modulus were
evaluated at the age of 7, 28, and 91 days. Moreover, the chloride
ingress test was carried out on the CWA mortars in a 5.0% NaCl
solution for 48 weeks. The chloride diffusion was assessed by using an
electron probe microanalysis (EPMA). To consider the relation of the
apparent chloride diffusion coefficient and the pore size, the pore size
distribution test was also performed using a mercury intrusion
porosimetry at the same time with the EPMA. The compressive
strength of the CWA mortars with the GGBS was higher than that
without the GGBS at the age of 28 and 91 days. The resistance to the
chloride ingress of the CWA mortar was effective in proportion to the
GGBS replacement level.