Abstract: In recent years, the use of the aluminum based alloys
in the industry and technology are increasing. Alloying elements in
aluminum have further been improving the strength and stiffness
properties that provide superior compared to other metals. In this
study, investigation of physical properties (microstructure,
microhardness, tensile strength, electrical conductivity and thermal
properties) in the Al-12.6wt.%Si-%2wt.Ni ternary alloy were
investigated. Al-Si-Ni alloy was prepared in vacuum atmosphere. The
samples were directionally solidified upwards with different growth
rate V (8.3−165.45 μm/s) at constant temperature gradient G (7.73
K/mm). The flake spacings (λ), microhardness (HV), ultimate tensile
strength (σ), electrical resistivity (ρ) and thermal properties (H, Cp,
Tm) of the samples were measured. Influence of the growth rate and
spacings on microhardness, ultimate tensile strength and electrical
resistivity were investigated and relationships between them were
obtained. According to results, λ values decrease with increasing V,
but HV, σ and ρ values increase with increasing V. Variations of
electrical resistivity (ρ) of solidified samples were also measured.
The enthalpy of fusion (H) and specific heat (Cp) for the alloy was
also determined by differential scanning calorimeter (DSC) from
heating trace during the transformation from liquid to solid. The
results in this work were compared with the previous similar
experimental results.
Abstract: Photovoltaic (PV) power generation systems, mainly
small scale, are rapidly being deployed in Jordan. The impact of these
systems on the grid has not been studied or analyzed. These systems
can cause many technical problems such as reverse power flows and
voltage rises in distribution feeders, and real and reactive power
transients that affect the operation of the transmission system. To
fully understand and address these problems, extensive research,
simulation, and case studies are required. To this end, this paper
studies the cloud shadow effect on the power generation of a ground
mounted PV system installed at the test field of the Renewable
Energy Center at the Applied Science University.
Abstract: The LSTF experiment simulating the SGTR accident at
the Mihama Unit-2 reactor is analyzed using the RELAP5/MOD3.3
code. In the accident, and thus in the experiment, the ECC water was
injected not only into the cold legs but into the upper plenum. Overall
transients during the experiment such as pressures and fluid
temperatures are simulated well by the code. The cold-leg fluid
temperatures are shown to decrease if the upper plenum injection
system is connected to the cold leg. It is found that the cold-leg fluid
temperatures also decrease if the upper-plenum injection is not used
and the cold-leg injection alone is actuated.
Abstract: In order to achieve high data rate and increase the
spectral efficiency, multiple input multiple output (MIMO) system has
been proposed. However, multiple antennas are limited by size and
cost. Therefore, recently developed cooperative diversity scheme,
which profits the transmit diversity only with the existing hardware by
constituting a virtual antenna array, can be a solution. However, most
of the introduced cooperative techniques have a common fault of
decreased transmission rate because the destination should receive the
decodable compositions of symbols from the source and the relay. In
this paper, we propose a cooperative cyclic delay diversity (CDD)
scheme that use hierarchical modulation. This scheme is free from the
rate loss and allows seamless cooperative communication.
Abstract: In this study, electric field distribution analyses for
three pylon models are carried out by a Finite Element Method
(FEM) based software. Analyses are performed in both stationary and
time domains to observe instantaneous values along with the
effective ones. Considering the results of the study, different line
geometries is considerably affecting the magnitude and distribution
of electric field although the line voltages are the same. Furthermore,
it is observed that maximum values of instantaneous electric field
obtained in time domain analysis are quite higher than the effective
ones in stationary mode. In consequence, electric field distribution
analyses should be individually made for each different line model
and the limit exposure values or distances to residential buildings
should be defined according to the results obtained.
Abstract: Facility location is a complex real-world problem
which needs a strategic management decision. This paper provides a
general review on studies, efforts and developments in Facility
Location Problems which are classical optimization problems having
a wide-spread applications in various areas such as transportation,
distribution, production, supply chain decisions and
telecommunication. Our goal is not to review all variants of different
studies in FLPs or to describe very detailed computational techniques
and solution approaches, but rather to provide a broad overview of
major location problems that have been studied, indicating how they
are formulated and what are proposed by researchers to tackle the
problem. A brief, elucidative table based on a grouping according to
“General Problem Type” and “Methods Proposed” used in the studies
is also presented at the end of the work.
Abstract: Below-knee amputees commonly experience
asymmetrical gait patterns. It is generally believed that ischemia is
related to the formation of pressure sores due to uneven distribution
of forces. Micro-vascular responses can reveal local malnutrition.
Changes in local skin blood supply under various external loading
conditions have been studied for a number of years. Radionuclide
clearance, photo-plethysmography, trans-cutaneous oxygen tension
along with other studies showed that the blood supply would be
influenced by the epidermal forces, and the rate and the amount of
blood supply would decrease with increased epidermal loads being
shear forces or normal forces. Several cases of socket designs were
investigated using Finite Element Model (FEM) and Design of
Experiment (DOE) to increase flexibility and minimize the pressure
at the limb/socket interface using ultra high molecular weight
polyethylene (UHMWPE) and polyamide 6 (PA6) or Duraform. The
pressure reliefs at designated areas where reducing thickness is
involved are seen to be critical in determination of amputees’ comfort
and are very important to clinical applications. Implementing a hole
between the Patellar Tendon (PT) and Distal Tibia (DT) would
decrease stiffness and increase prosthesis range of motion where
flexibility is needed. In addition, displacement and prosthetic energy
storage increased without compromising mechanical efficiency and
prosthetic design integrity.
Abstract: In this paper, monitoring and control of tap changer
mechanism of a transformer implementation in an Intelligent
Electronic Device (IED) is discussed. It has been a custom for
decades to provide a separate panel for on load tap changer control
for monitoring the tap position. However, this facility cannot either
record or transfer the information to remote control centers. As there
is a technology shift towards the smart grid protection and control
standards, the need for implementing remote control and monitoring
has necessitated the implementation of this feature in numerical
relays. This paper deals with the programming, settings and logic
implementation which is applicable to both IEC 61850 compatible
and non-compatible IEDs thereby eliminating the need for separate
tap changer control equipment. The monitoring mechanism has been
implemented in a 28MVA, 110 /6.9kV transformer with 16 tap
position with GE make T60 IED at Ultratech cement limited
Gulbarga, Karnataka and is in successful service.
Abstract: Sewer deposits have been identified as a major cause
of dysfunctions in combined sewer systems regarding sewer
management, which induces different negative consequents resulting
in poor hydraulic conveyance, environmental damages as well as
worker’s health. In order to overcome the problematics of
sedimentation, flushing has been considered as the most operative
and cost-effective way to minimize the sediments impacts and
prevent such challenges. Flushing, by prompting turbulent wave
effects, can modify the bed form depending on the hydraulic
properties and geometrical characteristics of the conduit. So far, the
dynamics of the bed-load during high-flow events in combined sewer
systems as a complex environment is not well understood, mostly due
to lack of measuring devices capable to work in the “hostile” in
combined sewer system correctly. In this regards, a one-episode
flushing issue from an opening gate valve with weir function was
carried out in a trunk sewer in Paris to understand its cleansing
efficiency on the sediments (thickness: 0-30 cm). During more than
1h of flushing within 5 m distance in downstream of this flushing
device, a maximum flowrate and a maximum level of water have
been recorded at 5 m in downstream of the gate as 4.1 m3/s and 2.1
m respectively. This paper is aimed to evaluate the efficiency of this
type of gate for around 1.1 km (from the point -50 m to +1050 m in
downstream from the gate) by (i) determining bed grain-size
distribution and sediments evolution through the sewer channel, as
well as their organic matter content, and (ii) identifying sections that
exhibit more changes in their texture after the flush. For the first one,
two series of sampling were taken from the sewer length and then
analyzed in laboratory, one before flushing and second after, at same
points among the sewer channel. Hence, a non-intrusive sampling
instrument has undertaken to extract the sediments smaller than the
fine gravels. The comparison between sediments texture after the
flush operation and the initial state, revealed the most modified zones
by the flush effect, regarding the sewer invert slope and hydraulic
parameters in the zone up to 400 m from the gate. At this distance,
despite the increase of sediment grain-size rages, D50 (median grainsize)
varies between 0.6 mm and 1.1 mm compared to 0.8 mm and 10
mm before and after flushing, respectively. Overall, regarding the
sewer channel invert slope, results indicate that grains smaller than
sands (< 2 mm) are more transported to downstream along about 400
m from the gate: in average 69% before against 38% after the flush
with more dispersion of grain-sizes distributions. Furthermore, high
effect of the channel bed irregularities on the bed material evolution
has been observed after the flush.
Abstract: Commercial banks in Nigeria adopted many strategies
to attract fresh deposits including the use of high deposit rate.
However, pricing of banking services moved in favor of the banks at
the expense of customers, resulting in their seeking other investment
alternatives rather than saving their money in the bank. Both deposit
and lending rates were greatly influenced by the Central Bank of
Nigeria (CBN) decision on interest rate. Therefore, commercial bank
effort to attract deposits via manipulation of her rates was greatly
limited, otherwise the banks will be giving out more than it earned.
The study aimed at examining the relationship between interest rate
and fixed fund deposit of commercial banks, how policy-controlled
interest rate affected commercial bank’s fixed fund deposit The
researcher employed ordinary least square technique, using, multiple
linear regression, unrestricted vector auto-regression, correlation
matrix test, granger causality and impulse response graph in the
analysis. Commercial bank’s interest rates affected commercial
bank’s fixed fund deposit significantly while policy-controlled
interest rate did not significantly transmit through the commercial
bank’s interest rates to affect fixed fund deposit. While commercial
banks seek creative ways to expand their fixed fund deposit, policy
authorities in Nigeria should better coordinate interest rate fluctuation
and induce competition in the entire financial sector.
Abstract: Conductivity properties of DNA molecule is
investigated in a simple, but chemically specific approach that is
intimately related to the Su-Schrieffer-Heeger (SSH) model. This
model is a tight-binding linear nanoscale chain. We have tried to
study the electrical current flowing in DNA and investigated the
characteristic I-V diagram. As a result, It is shown that there are the
(quasi-) ohmic areas in I-V diagram. On the other hand, the regions
with a negative differential resistance (NDR) are detectable in
diagram.
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: The use of Flexible AC Transmission System
(FACTS) devices in a power system can potentially overcome
limitations of the present mechanically controlled transmission
system. Also, the advance of technology makes possible to include
new energy storage devices in the electrical power system. The
integration of Superconducting Magnetic Energy Storage (SMES)
into Static Synchronous Compensator (STATCOM) can lead to
increase their flexibility in improvement of power system dynamic
behaviour by exchanging both active and reactive powers with power
grids. This paper describes structure and behaviour of SMES,
specifications and performance principles of the STATCOM/SMES
compensator. Moreover, the benefits and effectiveness of integrated
SMES with STATCOM in power systems is presented. Also, the
performance of the STATCOM/SMES compensator is evaluated
using an IEEE 3-bus system through the dynamic simulation by
PSCAD/EMTDC software.
Abstract: High frequency automotive interior noise above 500
Hz considerably affects automotive passenger comfort. To reduce this
noise, sound insulation material is often laminated on body panels or
interior trim panels. For a more effective noise reduction, the sound
reduction properties of this laminated structure need to be estimated.
We have developed a new calculate tool that can roughly calculate the
sound absorption and insulation properties of laminate structure and
handy for designers. In this report, the outline of this tool and an
analysis example applied to floor mat are introduced.
Abstract: In this paper, we report the development of the device
for diagnostics of cardiovascular system state and associated
automated workstation for large-scale medical measurement data
collection and analysis. It was shown that optimal design for the
monitoring device is wristband as it represents engineering trade-off
between accuracy and usability. Monitoring device is based on the
infrared reflective photoplethysmographic sensor, which allows
collecting multiple physiological parameters, such as heart rate and
pulsing wave characteristics. Developed device uses BLE interface
for medical and supplementary data transmission to the coupled
mobile phone, which processes it and send it to the doctor's
automated workstation. Results of this experimental model
approbation confirmed the applicability of the proposed approach.
Abstract: In order to obtain efficient pollutants removal in
small-scale wastewater treatment plants, uniform water flow has to be
achieved. The experimental setup, designed for treating high-load
wastewater (leachate), consists of two aerobic biological reactors and
a lamellar settler. Both biological tanks were aerated by using three
different types of aeration systems - perforated pipes, membrane air
diffusers and tube ceramic diffusers. The possibility of homogenizing
the water mass with each of the air diffusion systems was evaluated
comparatively. The oxygen concentration was determined by optical
sensors with data logging. The experimental data was analyzed
comparatively for all three different air dispersion systems aiming to
identify the oxygen concentration variation during different
operational conditions. The Oxygenation Capacity was calculated for
each of the three systems and used as performance and selection
parameter. The global mass transfer coefficients were also evaluated
as important tools in designing the aeration system. Even though
using the tubular porous diffusers leads to higher oxygen
concentration compared to the perforated pipe system (which
provides medium-sized bubbles in the aqueous solution), it doesn’t
achieve the threshold limit of 80% oxygen saturation in less than 30
minutes. The study has shown that the optimal solution for the
studied configuration was the radial air diffusers which ensure an
oxygen saturation of 80% in 20 minutes. An increment of the values
was identified when the air flow was increased.
Abstract: The present study applies the inverse method and
three-dimensional CFD commercial software in conjunction with the
experimental temperature data to investigate the heat transfer and fluid
flow characteristics of the plate-fin heat sink in a rectangular closed
enclosure. The inverse method with the finite difference method and
the experimental temperature data is applied to determine the
approximate heat transfer coefficient. Later, based on the obtained
results, the zero-equation turbulence model is used to obtain the heat
transfer and fluid flow characteristics between two fins. T0 validate
the accuracy of the results obtained, the comparison of the heat transfer
coefficient is made. The obtained temperature at selected
measurement locations of the fin is also compared with experimental
data. The effect of the height of the rectangular enclosure on the
obtained results is discussed.
Abstract: In this research, a questionnaire survey was conducted
to measure nap, drowsiness and fatigue of drivers who work for long
shifts, to discuss about the work environment and health conditions for
taxi and bus drivers who work at night-time. The questionnaire sheet
used for this research was organized into the following categories:
tension/tiredness, drowsiness while driving, and the nap situation
during night-time work. The number of taxi drivers was 127 and the
number of bus drivers was 40. Concerning the results of a comparison
of nap hours of taxi and bus drivers, the taxi drivers’ nap hours are
overwhelmingly shorter, and also the frequency of drivers who
experience drowsiness is higher. The burden on bus drivers does not
change because of the system of a two-driver rotation shift. In
particular, the working environment of the taxi driver may lead to
greater fatigue accumulation than the bus driver’s environment.
Abstract: New environmental regulations and the increasing
market preference for companies that respect the ecosystem had
encouraged the industry to look after new treatments for its effluents.
The sugar industry, one of the largest emitter of environmental
pollutants, follows this tendency. Membrane technology is
convenient for separation of suspended solids, colloids and high
molecular weight materials that are present in a wastewater from
sugar industry. The idea is to microfilter the wastewater, where the
permeate passes through the membrane and becomes available for
recycle and re-use in the sugar manufacturing process. For
microfiltration of this effluent a tubular ceramic membrane was used
with a pore size of 200 nm at transmembrane pressure in range of 1–3
bars and in range of flow rate of 50–150 l/h. Kenics static mixer was
used for permeate flux enhancement. Turbidity and suspended solids
were removed and the permeate flux was continuously monitored
during the microfiltration process. The flux achieved after 90 minutes
of microfiltration was in a range of 50–70 l/m2h. The obtained
turbidity decrease was in the range of 50-99 % and total amount of
suspended solids was removed.
Abstract: In insulation and cooling of power transformers
various liquids are used. Mineral oils have wide availability and low
cost. However, they have a poor biodegradability potential and lower
fire point in comparison with other insulating liquids. Use of a liquid
having high biodegradability is important due to environmental
consideration. This paper investigates edible corn oil as an alternative
to mineral oil. Various properties of mineral and corn oil like
breakdown voltage, dissipation factor, relative dielectric constant,
power loss and resistivity were measured according to different
standards.