Abstract: This paper investigates the thermo-electric effects
around the crack and notch tips under the electric current load. The
research methods include the finite element analysis and thermal
imaging experiment. The finite element solutions show that the electric
current density field concentrates at the crack tip. Due to the Joule
heating, this electric concentration causes the hot spot at the tip zone.
From numerical and experimental results, this hot spot is identified.
The temperature of the hot spot is affected by the electric load,
operation time and geometry of the sample.
Abstract: The Hall Coefficient (HC) and the Magnetoresistance (MR) have been studied in two-dimensional systems. The HC and the MR in Rectangular Quantum Wire (RQW) subjected to a crossed DC electric field and magnetic field in the presence of a Strong Electromagnetic Wave (EMW) characterized by electric field are studied in this work. Using the quantum kinetic equation for electrons interacting with optical phonons, we obtain the analytic expressions for the HC and the MR with a dependence on magnetic field, EMW frequency, temperatures of systems and the length characteristic parameters of RQW. These expressions are different from those obtained for bulk semiconductors and cylindrical quantum wires. The analytical results are applied to GaAs/GaAs/Al. For this material, MR depends on the ratio of the EMW frequency to the cyclotron frequency. Indeed, MR reaches a minimum at the ratio 5/4, and when this ratio increases, it tends towards a saturation value. The HC can take negative or positive values. Each curve has one maximum and one minimum. When magnetic field increases, the HC is negative, achieves a minimum value and then increases suddenly to a maximum with a positive value. This phenomenon differs from the one observed in cylindrical quantum wire, which does not have maximum and minimum values.
Abstract: Mumbai, being traditionally the epicenter of India's
trade and commerce, the existing major ports such as Mumbai and
Jawaharlal Nehru Ports (JN) situated in Thane estuary are also
developing its waterfront facilities. Various developments over the
passage of decades in this region have changed the tidal flux
entering/leaving the estuary. The intake at Pir-Pau is facing the
problem of shortage of water in view of advancement of shoreline,
while jetty near Ulwe faces the problem of ship scheduling due to
existence of shallower depths between JN Port and Ulwe Bunder. In
order to solve these problems, it is inevitable to have information
about tide levels over a long duration by field measurements.
However, field measurement is a tedious and costly affair;
application of artificial intelligence was used to predict water levels
by training the network for the measured tide data for one lunar tidal
cycle. The application of two layered feed forward Artificial Neural
Network (ANN) with back-propagation training algorithms such as
Gradient Descent (GD) and Levenberg-Marquardt (LM) was used to
predict the yearly tide levels at waterfront structures namely at Ulwe
Bunder and Pir-Pau. The tide data collected at Apollo Bunder, Ulwe,
and Vashi for a period of lunar tidal cycle (2013) was used to train,
validate and test the neural networks. These trained networks having
high co-relation coefficients (R= 0.998) were used to predict the tide
at Ulwe, and Vashi for its verification with the measured tide for the
year 2000 & 2013. The results indicate that the predicted tide levels
by ANN give reasonably accurate estimation of tide. Hence, the
trained network is used to predict the yearly tide data (2015) for
Ulwe. Subsequently, the yearly tide data (2015) at Pir-Pau was
predicted by using the neural network which was trained with the
help of measured tide data (2000) of Apollo and Pir-Pau. The analysis of measured data and study reveals that: The
measured tidal data at Pir-Pau, Vashi and Ulwe indicate that there is
maximum amplification of tide by about 10-20 cm with a phase lag
of 10-20 minutes with reference to the tide at Apollo Bunder
(Mumbai). LM training algorithm is faster than GD and with increase
in number of neurons in hidden layer and the performance of the
network increases. The predicted tide levels by ANN at Pir-Pau and
Ulwe provides valuable information about the occurrence of high and
low water levels to plan the operation of pumping at Pir-Pau and
improve ship schedule at Ulwe.
Abstract: The source of the jet noise is generated by rocket exhaust plume during rocket engine testing. A domain decomposition approach is applied to the jet noise prediction in this paper. The aerodynamic noise coupling is based on the splitting into acoustic sources generation and sound propagation in separate physical domains. Large Eddy Simulation (LES) is used to simulate the supersonic jet flow. Based on the simulation results of the flow-fields, the jet noise distribution of the sound pressure level is obtained by applying the Ffowcs Williams-Hawkings (FW-H) acoustics equation and Fourier transform. The calculation results show that the complex structures of expansion waves, compression waves and the turbulent boundary layer could occur due to the strong interaction between the gas jet and the ambient air. In addition, the jet core region, the shock cell and the sound pressure level of the gas jet increase with the nozzle size increasing. Importantly, the numerical simulation results of the far-field sound are in good agreement with the experimental measurements in directivity.
Abstract: In this paper, we investigate the low-lying energy
levels of the two-dimensional parabolic graphene quantum dots
(GQDs) in the presence of topological defects with long range
Coulomb impurity and subjected to an external uniform magnetic
field. The low-lying energy levels of the system are obtained within
the framework of the perturbation theory. We theoretically
demonstrate that a valley splitting can be controlled by geometrical
parameters of the graphene quantum dots and/or by tuning a uniform
magnetic field, as well as topological defects. It is found that, for
parabolic graphene dots, the valley splitting occurs due to the
introduction of spatial confinement. The corresponding splitting is
enhanced by the introduction of a uniform magnetic field and it
increases by increasing the angle of the cone in subcritical regime.
Abstract: Magnetic Resonance Imaging Contrast Agents
(MRI-CM) are significant in the clinical and biological imaging as
they have the ability to alter the normal tissue contrast, thereby
affecting the signal intensity to enhance the visibility and detectability
of images. Superparamagnetic Iron Oxide (SPIO) nanoparticles,
coated with dextran or carboxydextran are currently available for
clinical MR imaging of the liver. Most SPIO contrast agents are
T2 shortening agents and Resovist (Ferucarbotran) is one of a
clinically tested, organ-specific, SPIO agent which has a low
molecular carboxydextran coating. The enhancement effect of
Resovist depends on its relaxivity which in turn depends on factors
like magnetic field strength, concentrations, nanoparticle properties,
pH and temperature. Therefore, this study was conducted to
investigate the impact of field strength and different contrast
concentrations on enhancement effects of Resovist. The study
explored the MRI signal intensity of Resovist in the physiological
range of plasma from T2-weighted spin echo sequence at three
magnetic field strengths: 0.47 T (r1=15, r2=101), 1.5 T (r1=7.4,
r2=95), and 3 T (r1=3.3, r2=160) and the range of contrast
concentrations by a mathematical simulation. Relaxivities of r1 and r2
(L mmol-1 Sec-1) were obtained from a previous study and the selected
concentrations were 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5,
0.6, 0.7, 0.8, 0.9, 1.0, 2.0, and 3.0 mmol/L. T2-weighted images were
simulated using TR/TE ratio as 2000 ms /100 ms. According to the
reference literature, with increasing magnetic field strengths, the
r1 relaxivity tends to decrease while the r2 did not show any
systematic relationship with the selected field strengths. In parallel,
this study results revealed that the signal intensity of Resovist at lower
concentrations tends to increase than the higher concentrations. The
highest reported signal intensity was observed in the low field strength
of 0.47 T. The maximum signal intensities for 0.47 T, 1.5 T and 3 T
were found at the concentration levels of 0.05, 0.06 and 0.05 mmol/L,
respectively. Furthermore, it was revealed that, the concentrations
higher than the above, the signal intensity was decreased
exponentially. An inverse relationship can be found between the field
strength and T2 relaxation time, whereas, the field strength was
increased, T2 relaxation time was decreased accordingly. However,
resulted T2 relaxation time was not significantly different between
0.47 T and 1.5 T in this study. Moreover, a linear correlation of
transverse relaxation rates (1/T2, s–1) with the concentrations of
Resovist can be observed. According to these results, it can conclude
that the concentration of SPIO nanoparticle contrast agents and the
field strengths of MRI are two important parameters which can affect the signal intensity of T2-weighted SE sequence. Therefore, when MR
imaging those two parameters should be considered prudently.
Abstract: Seeking and sharing knowledge on online forums
have made them popular in recent years. Although online forums are
valuable sources of information, due to variety of sources of
messages, retrieving reliable threads with high quality content is an
issue. Majority of the existing information retrieval systems ignore
the quality of retrieved documents, particularly, in the field of thread
retrieval. In this research, we present an approach that employs
various quality features in order to investigate the quality of retrieved
threads. Different aspects of content quality, including completeness,
comprehensiveness, and politeness, are assessed using these features,
which lead to finding not only textual, but also conceptual relevant
threads for a user query within a forum. To analyse the influence of
the features, we used an adopted version of voting model thread
search as a retrieval system. We equipped it with each feature solely
and also various combinations of features in turn during multiple
runs. The results show that incorporating the quality features
enhances the effectiveness of the utilised retrieval system
significantly.
Abstract: The aim of irrigation is to recharge the available water
in the soil. Quality of irrigation water is essential for the yield and
quality of crops produced, maintenance of soil productivity and
protection of the environment. The analysis of irrigation water arises
as a need to know the impact of irrigation water on the yield of crops,
the effect, and the necessary control measures to rectify the effect of
this for optimum production and yield of crops. This study was conducted to assess the quality of irrigation water
with its performance on crop planted, in Josepdam irrigation scheme
Bacita, Nigeria. Field visits were undertaken to identify and locate
water supply sources and collect water samples from these sources;
X1 Drain, Oshin, River Niger loop and Ndafa. Laboratory
experiments were then undertaken to determine the quality of raw
water from these sources. The analysis was carried for various parameters namely; physical
and chemical analyses after water samples have been taken from four
sources. The samples were tested in laboratory. Results showed that
the raw water sources shows no salinity tendencies with SAR values
less than 1me/l and Ecvaules at Zero while the pH were within the
recommended range by FAO, there are increase in potassium and
sulphate content contamination in three of the location. From this, it
is recommended that there should be proper monitoring of the
scheme by conducting analysis of water and soil in the environment,
preferable test should be carried out at least one year to cover the
impact of seasonal variations and to determine the physical and
chemical analysis of the water used for irrigation at the scheme.
Abstract: Many cluster based routing protocols have been
proposed in the field of wireless sensor networks, in which a group of
nodes are formed as clusters. A cluster head is selected from one
among those nodes based on residual energy, coverage area, number
of hops and that cluster-head will perform data gathering from
various sensor nodes and forwards aggregated data to the base station
or to a relay node (another cluster-head), which will forward the
packet along with its own data packet to the base station. Here a
Game Theory based Diligent Energy Utilization Algorithm (GTDEA)
for routing is proposed. In GTDEA, the cluster head selection is done
with the help of game theory, a decision making process, that selects
a cluster-head based on three parameters such as residual energy
(RE), Received Signal Strength Index (RSSI) and Packet Reception
Rate (PRR). Finding a feasible path to the destination with minimum
utilization of available energy improves the network lifetime and is
achieved by the proposed approach. In GTDEA, the packets are
forwarded to the base station using inter-cluster routing technique,
which will further forward it to the base station. Simulation results
reveal that GTDEA improves the network performance in terms of
throughput, lifetime, and power consumption.
Abstract: Aerobic dance has becoming a popular mode of
exercise especially among women due to its fun nature. With a catchy
music background and joyful dance steps, aerobic dancers would be
able to have fun while sweating out. Depending on its level of
aggressiveness, aerobic may also improve and maintain
cardiorespiratory fitness other than being a great tool for weight loss.
This study intends to prove that aerobic dance activity can bring the
same, if not better impacts on health than other types of
cardiovascular exercise such as jogging and cycling. The objective of
this study was to evaluate and identify the effect of six weeks aerobic
dance on cardiovascular fitness and weight loss among women. This
study, which was held in Seremban Fit Challenge, used a quasiexperimental
design. The subjects selected include a total of 14
women (n = 14) with age (32.4 years old ± 9.1), weight (65.93 kg ±
11.24) and height (165.36 ± 3.46) who joined the Seremban Fit
Challenge Season 13. The subjects were asked to join an aerobic
dance class with a duration of one hour for six weeks in a row. As for
the outcome, cardiovascular fitness was measured with a 1-mile run
test while any changes on weight were measured using the weighing
scale. The result showed that there was a significant difference
between pre and post-test for cardiovascular fitness when p = 0.02
Abstract: This paper outlines the development of an
experimental technique in quantifying supersonic jet flows, in an
attempt to avoid seeding particle problems frequently associated with
particle-image velocimetry (PIV) techniques at high Mach numbers.
Based on optical flow algorithms, the idea behind the technique
involves using high speed cameras to capture Schlieren images of the
supersonic jet shear layers, before they are subjected to an adapted
optical flow algorithm based on the Horn-Schnuck method to
determine the associated flow fields. The proposed method is capable
of offering full-field unsteady flow information with potentially
higher accuracy and resolution than existing point-measurements or
PIV techniques. Preliminary study via numerical simulations of a
circular de Laval jet nozzle successfully reveals flow and shock
structures typically associated with supersonic jet flows, which serve
as useful data for subsequent validation of the optical flow based
experimental results. For experimental technique, a Z-type Schlieren
setup is proposed with supersonic jet operated in cold mode,
stagnation pressure of 4 bar and exit Mach of 1.5. High-speed singleframe
or double-frame cameras are used to capture successive
Schlieren images. As implementation of optical flow technique to
supersonic flows remains rare, the current focus revolves around
methodology validation through synthetic images. The results of
validation test offers valuable insight into how the optical flow
algorithm can be further improved to improve robustness and
accuracy. Despite these challenges however, this supersonic flow
measurement technique may potentially offer a simpler way to
identify and quantify the fine spatial structures within the shock shear
layer.
Abstract: At the Savonia University of Applied Sciences (UAS),
curriculum and studies have been improved by applying an Open
Innovation Space approach (OIS). It is based on multidisciplinary
action learning. The key elements of OIS-ideology are work-life
orientation, and student-centric communal learning. In this approach,
every participant can learn from each other and innovations will be
created. In this social innovation educational approach, all practices
are carried out in close collaboration with enterprises in real-life
settings, not in classrooms. As an example, in this paper, Savonia
UAS’s Future Food RDI hub (FF) shows how OIS practices are
implemented by providing food product development and consumer
research services for enterprises in close collaboration with
academicians, students and consumers. In particular one example of
OIS experimentation in the field is provided by a consumer research
carried out utilizing verbal analysis protocol combined with audiovisual
observation (VAP-WAVO). In this case, all co-learners were
acting together in supermarket settings to collect the relevant data for
a product development and the marketing department of a company.
The company benefitted from the results obtained, students were
more satisfied with their studies, educators and academicians were
able to obtain good evidence for further collaboration as well as
renewing curriculum contents based on the requirements of working
life. In addition, society will benefit over time as young university
adults find careers more easily through their OIS related food science
studies. Also this knowledge interaction model re-news education
practices and brings working-life closer to educational research
institutes.
Abstract: Fractal based digital image compression is a specific
technique in the field of color image. The method is best suited for
irregular shape of image like snow bobs, clouds, flame of fire; tree
leaves images, depending on the fact that parts of an image often
resemble with other parts of the same image. This technique has
drawn much attention in recent years because of very high
compression ratio that can be achieved. Hybrid scheme incorporating
fractal compression and speedup techniques have achieved high
compression ratio compared to pure fractal compression. Fractal
image compression is a lossy compression method in which selfsimilarity
nature of an image is used. This technique provides high
compression ratio, less encoding time and fart decoding process. In
this paper, fractal compression with quad tree and DCT is proposed
to compress the color image. The proposed hybrid schemes require
four phases to compress the color image. First: the image is
segmented and Discrete Cosine Transform is applied to each block of
the segmented image. Second: the block values are scanned in a
zigzag manner to prevent zero co-efficient. Third: the resulting image
is partitioned as fractals by quadtree approach. Fourth: the image is
compressed using Run length encoding technique.
Abstract: Teaching of mathematics to engineering students is an
open ended problem in education. The main goal of mathematics
learning for engineering students is the ability of applying a wide
range of mathematical techniques and skills in their engineering
classes and later in their professional work. Most of the
undergraduate engineering students and faculties feels that no efforts
and attempts are made to demonstrate the applicability of various
topics of mathematics that are taught thus making mathematics
unavoidable for some engineering faculty and their students. The lack
of understanding of concepts in engineering mathematics may hinder
the understanding of other concepts or even subjects. However, for
most undergraduate engineering students, mathematics is one of the
most difficult courses in their field of study. Most of the engineering students never understood mathematics or
they never liked it because it was too abstract for them and they could
never relate to it. A right balance of application and concept based
teaching can only fulfill the objectives of teaching mathematics to
engineering students. It will surely improve and enhance their
problem solving and creative thinking skills. In this paper, some practical (informal) ways of making
mathematics-teaching application based for the engineering students
is discussed. An attempt is made to understand the present state of
teaching mathematics in engineering colleges. The weaknesses and
strengths of the current teaching approach are elaborated. Some of
the causes of unpopularity of mathematics subject are analyzed and a
few pragmatic suggestions have been made. Faculty in mathematics
courses should spend more time discussing the applications as well as
the conceptual underpinnings rather than focus solely on strategies
and techniques to solve problems. They should also introduce more
‘word’ problems as these problems are commonly encountered in
engineering courses. Overspecialization in engineering education
should not occur at the expense of (or by diluting) mathematics and
basic sciences. The role of engineering education is to provide the
fundamental (basic) knowledge and to teach the students simple
methodology of self-learning and self-development. All these issues
would be better addressed if mathematics and engineering faculty
join hands together to plan and design the learning experiences for
the students who take their classes. When faculties stop competing
against each other and start competing against the situation, they will
perform better. Without creating any administrative hassles these
suggestions can be used by any young inexperienced faculty of
mathematics to inspire engineering students to learn engineering
mathematics effectively.
Abstract: Energy has a prominent role for development of
nations. Countries which have energy resources also have strategic
power in the international trade of energy since it is essential for all
stages of production in the economy. Thus, it is important for
countries to analyze the weaknesses and strength of the system. On
the other side, international trade is one of the fields that are analyzed
as a complex network via network analysis. Complex network is one
of the tools to analyze complex systems with heterogeneous agents
and interaction between them. A complex network consists of nodes
and the interactions between these nodes. Total properties which
emerge as a result of these interactions are distinct from the sum of
small parts (more or less) in complex systems. Thus, standard
approaches to international trade are superficial to analyze these
systems. Network analysis provides a new approach to analyze
international trade as a network. In this network, countries constitute
nodes and trade relations (export or import) constitute edges. It
becomes possible to analyze international trade network in terms of
high degree indicators which are specific to complex networks such
as connectivity, clustering, assortativity/disassortativity, centrality,
etc. In this analysis, international trade of crude oil and coal which
are types of fossil fuel has been analyzed from 2005 to 2014 via
network analysis. First, it has been analyzed in terms of some
topological parameters such as density, transitivity, clustering etc.
Afterwards, fitness to Pareto distribution has been analyzed via
Kolmogorov-Smirnov test. Finally, weighted HITS algorithm has
been applied to the data as a centrality measure to determine the real
prominence of countries in these trade networks. Weighted HITS
algorithm is a strong tool to analyze the network by ranking countries
with regards to prominence of their trade partners. We have
calculated both an export centrality and an import centrality by
applying w-HITS algorithm to the data. As a result, impacts of the
trading countries have been presented in terms of high-degree
indicators.
Abstract: The paper focuses on the distance laboratory
organisation for training the electrical engineering staff and students
in the fields of electrical drive and power electronics. To support
online knowledge acquisition and professional enhancement, new
challenges in remote education based on an active learning approach
with self-assessment have been emerged by the authors. Following
the literature review and explanation of the improved assessment
methodology, the concept and technological basis of the labs
arrangement are presented. To decrease the gap between the distance
study of the up-to-date equipment and other educational activities in
electrical engineering, the improvements in the following-up the
learners’ progress and feedback composition are introduced. An
authoring methodology that helps to personalise knowledge
acquisition and enlarge Web-based possibilities is described.
Educational management based on self-assessment is discussed.
Abstract: The field of instrumentation electronics is undergoing
an explosive growth, due to its wide range of applications. The
proliferation of electrical devices in a close working proximity can
negatively influence each other’s performance. The degradation in
the performance is due to electromagnetic interference (EMI). This paper investigates the negative effects of electromagnetic
interference originating in the General Purpose Interface Bus (GPIB)
control-network of the AC-DC transfer measurement system.
Remedial measures of reducing measurement errors and failure of
range of industrial devices due to EMI have been explored. The ACDC
transfer measurement system was analysed for the commonmode
(CM) EMI effects. Further investigation of coupling path as
well as much accurate identification of noise propagation mechanism
has been outlined. To prevent the occurrence of common-mode
(ground loops) which was identified between the GPIB system
control circuit and the measurement circuit, a microcontroller-driven
GPIB switching isolator device was designed, prototyped,
programmed and validated. This mitigation technique has been
explored to reduce EMI effectively.
Abstract: In this paper, an Infinite Impulse Response (IIR) filter
has been designed and simulated on an Field Programmable Gate
Arrays (FPGA). The implementation is based on Multiply Add and
Accumulate (MAC) algorithm which uses multiply operations for
design implementation. Parallel Pipelined structure is used to
implement the proposed IIR Filter taking optimal advantage of the
look up table of target device. The designed filter has been
synthesized on Digital Signal Processor (DSP) slice based FPGA to
perform multiplier function of MAC unit. The DSP slices are useful
to enhance the speed performance. The proposed design is simulated
with Matlab, synthesized with Xilinx Synthesis Tool, and
implemented on FPGA devices. The Virtex 5 FPGA based design can
operate at an estimated frequency of 81.5 MHz as compared to 40.5
MHz in case of Spartan 3 ADSP based design. The Virtex 5 based
implementation also consumes less slices and slice flip flops of target
FPGA in comparison to Spartan 3 ADSP based implementation to
provide cost effective solution for signal processing applications.
Abstract: This paper aims to analysis the behavior of DC corona
discharge in wire-to-plate electrostatic precipitators (ESP). Currentvoltage
curves are particularly analyzed. Experimental results show
that discharge current is strongly affected by the applied voltage. The proposed method of current identification is to use the method
of least squares. Least squares problems that of into two categories:
linear or ordinary least squares and non-linear least squares,
depending on whether or not the residuals are linear in all unknowns.
The linear least-squares problem occurs in statistical regression
analysis; it has a closed-form solution. A closed-form solution (or
closed form expression) is any formula that can be evaluated in a
finite number of standard operations. The non-linear problem has no
closed-form solution and is usually solved by iterative.
Abstract: This research work is an experimental study, through
development of an adhesive from Prosopis africana endosperm. The
prosopis seed for this work were obtained from Enugu State in the
South East part of Nigeria. The seeds were prepared by separating the
endosperm from the seed coat and cotyledon. Three methods were
used to separate them, which are acidic method, roasting method and
boiling method. 20g of seed were treated with different
concentrations (25, 40, 55, 70, and 85% w/w) at 100°C and constant
time (30 minutes), under continuous stirring with magnetic stirrer.
Also 20g of seed were treated with sulphuric acid of concentrations
40% w/w at 100°C with different time (10, 15, 20, 25, 30 minutes),
under continuous stirring with magnetic stirrer. Finally, 20g of seed
were treated with sulphuric acid of concentrations 40% w/w at
different temperature (20°C, 40°C, 60°C, 80°C, and 100°C) with
constant time (30 minutes), under continuous stirring with magnetic
stirrer. The whole endosperm extracted was adhesive. The physical
properties of the adhesive were determined (appearance, odour, taste,
solubility, pH, size, and binding strength). The percentage of the
adhesive yield makes the commercialization of the seed in Nigeria
possible and profitable. The very high viscosity attained at low
concentrations makes prosopis adhesive an excellent thickener in the
food industry.