Abstract: In this work, an organic compound 5,10,15,20-
Tetrakis(3,5-di-tertbutylphenyl)porphyrinatocopper(II) (TDTBPPCu)
is studied as an active material for thin film electronic devices. To
investigate the electrical properties of TDTBPPCu, junction of
TDTBPPCu with heavily doped n-Si and Al is fabricated.
TDTBPPCu film was sandwiched between Al and n-Si electrodes.
Various electrical parameters of TDTBPPCu are determined. The
current-voltage characteristics of the junction are nonlinear,
asymmetric and show rectification behavior, which gives the clue of
formation of depletion region. This behavior indicates the potential
of TDTBPPCu for electronics applications. The current-voltage and
capacitance-voltage techniques are used to find the different
electronic parameters.
Abstract: Martensitic stainless steels have been extensively used for their good corrosion resistance and better mechanical properties. Heat treatment was suggested as one of the most excellent ways to this regard; hence, it affects the microstructure, mechanical and corrosion properties of the steel. In the current research work the microstructural changes and corrosion behavior in an AISI 420A stainless steel exposed to temperatures in the 980-1035oC range were investigated. The heat treatment is carried out in vacuum furnace within the said temperature range. The quenching of the samples was carried out in oil, brine and water media. The formation and stability of passive film was studied by Open Circuit Potential, Potentiodynamic polarization and Electrochemical Scratch Tests. The Electrochemical Impedance Spectroscopy results simulated with Equivalent Electrical Circuit suggested bilayer structure of outer porous and inner barrier oxide films. The quantitative data showed thick inner barrier oxide film retarded electrochemical reactions. Micrographs of the quenched samples showed sigma and chromium carbide phases which prove the corrosion resistance of steel alloy.
Abstract: One of the main environmental problems which affect extensive areas in the world is soil salinity. Traditional data collection methods are neither enough for considering this important environmental problem nor accurate for soil studies. Remote sensing data could overcome most of these problems. Although satellite images are commonly used for these studies, however there are still needs to find the best calibration between the data and real situations in each specified area. Neyshaboor area, North East of Iran was selected as a field study of this research. Landsat satellite images for this area were used in order to prepare suitable learning samples for processing and classifying the images. 300 locations were selected randomly in the area to collect soil samples and finally 273 locations were reselected for further laboratory works and image processing analysis. Electrical conductivity of all samples was measured. Six reflective bands of ETM+ satellite images taken from the study area in 2002 were used for soil salinity classification. The classification was carried out using common algorithms based on the best composition bands. The results showed that the reflective bands 7, 3, 4 and 1 are the best band composition for preparing the color composite images. We also found out, that hybrid classification is a suitable method for identifying and delineation of different salinity classes in the area.
Abstract: Condition monitoring of electrical power equipment
has attracted considerable attention for many years. The aim of this
paper is to use Labview with Fuzzy Logic controller to build a
simulation system to diagnose transformer faults and monitor its
condition. The front panel of the system was designed using
LabVIEW to enable computer to act as customer-designed
instrument. The dissolved gas-in-oil analysis (DGA) method was
used as technique for oil type transformer diagnosis; meanwhile
terminal voltages and currents analysis method was used for dry type
transformer. Fuzzy Logic was used as expert system that assesses all
information keyed in at the front panel to diagnose and predict the
condition of the transformer. The outcome of the Fuzzy Logic
interpretation will be displayed at front panel of LabVIEW to show
the user the conditions of the transformer at any time.
Abstract: Permanent rivers are the main sources of renewable
water supply for the croplands under the irrigation and drainage
schemes. They are also the major source of sediment loads transport
into the storage reservoirs of the hydro-electrical dams, diversion
weirs and regulating dams. Sedimentation process results from soil
erosion which is related to poor watershed management and human
intervention ion in the hydraulic regime of the rivers. These could
change the hydraulic behavior and as such, leads to riverbed and river
bank scouring, the consequences of which would be sediment load
transport into the dams and therefore reducing the flow discharge in
water intakes. The present paper investigate sedimentation process
by varying the Manning coefficient "n" by using the SHARC
software along the watercourse in the Dez River. Results indicated
that the optimum "n" within that river range is 0.0315 at which
quantity minimum sediment loads are transported into the Eastern
intake. Comparison of the model results with those obtained by those
from the SSIIM software within the same river reach showed a very
close proximity between them. This suggests a relative accuracy with
which the model can simulate the hydraulic flow characteristics and
therefore its suitability as a powerful analytical tool for project
feasibility studies and project implementation.
Abstract: Fats and oils are made of esterified hydrocarbons
(RCOOR-) and this work demonstrates the substitution of R by
multi-walled CNTs (MWNTs). The resultant materials are fluidic, oily,
electrically conducting and excellent lubricants. Esterified MWNTs
can also respond to magnetic field when tubules contain long segments
of Fe
Abstract: This paper presents the impact study of GTO Controlled Series Capacitor (GCSC) parameters on measured impedance (Zseen) by MHO distance relays for single transmission line high voltage 220 kV in the presence of single phase to earth fault with fault resistance (RF). The study deals with a 220 kV single electrical transmission line of Eastern Algerian transmission networks at Group Sonelgaz (Algerian Company of Electrical and Gas) compensated by series Flexible AC Transmission System (FACTS) i.e. GCSC connected at midpoint of the transmission line. The transmitted active and reactive powers are controlled by three GCSC-s. The effects of maximum reactive power injected as well as injected maximum voltage by GCSC on distance relays measured impedance is treated. The simulations results investigate the effects of GCSC injected parameters: variable reactance (XGCSC), variable voltage (VGCSC) and reactive power injected (QGCSC) on measured resistance and reactance in the presence of earth fault with resistance fault varied between 5 to 50 Ω for three cases study.
Abstract: Today with the rapid growth of telecommunications equipment, electronic and developing more and more networks of power, influence of electromagnetic waves on one another has become hot topic discussions. So in this article, this issue and appropriate mechanisms for EMC operations have been presented. First, impact of high voltage lines on the surrounding environment especially on the control room has been investigated, then to reduce electromagnetic radiation, various methods of shielding are provided and shielding effectiveness of them has been compared. It should be expressed that simulations have been done by the finite element method (FEM).
Abstract: Nowadays, engineering ceramics have significant
applications in different industries such as; automotive, aerospace,
electrical, electronics and even martial industries due to their
attractive physical and mechanical properties like very high hardness
and strength at elevated temperatures, chemical stability, low friction
and high wear resistance. However, these interesting properties plus
low heat conductivity make their machining processes too hard,
costly and time consuming. Many attempts have been made in order
to make the grinding process of engineering ceramics easier and
many scientists have tried to find proper techniques to economize
ceramics' machining processes. This paper proposes a new diamond
plunge grinding technique using ultrasonic vibration for grinding
Alumina ceramic (Al2O3). For this purpose, a set of laboratory
equipments have been designed and simulated using Finite Element
Method (FEM) and constructed in order to be used in various
measurements. The results obtained have been compared with the
conventional plunge grinding process without ultrasonic vibration
and indicated that the surface roughness and fracture strength
improved and the grinding forces decreased.
Abstract: In the current research, neuro-fuzzy model and regression model was developed to predict Material Removal Rate in Electrical Discharge Machining process for AISI D2 tool steel with copper electrode. Extensive experiments were conducted with various levels of discharge current, pulse duration and duty cycle. The experimental data are split into two sets, one for training and the other for validation of the model. The training data were used to develop the above models and the test data, which was not used earlier to develop these models were used for validation the models. Subsequently, the models are compared. It was found that the predicted and experimental results were in good agreement and the coefficients of correlation were found to be 0.999 and 0.974 for neuro fuzzy and regression model respectively
Abstract: Temperature rise in a transformer depends on variety
of parameters such as ambient temperature, output current and type
of the core. Considering these parameters, temperature rise estimation
is still complicated procedure. In this paper, we present a new model
based on simple electrical equivalent circuit. This method avoids the
complication associated to accurate estimation and is in very good
agreement with practice.
Abstract: A transient finite element model has been developed
to study the heat transfer and fluid flow during spot Gas Tungsten
Arc Welding (GTAW) on stainless steel. Temperature field, fluid
velocity and electromagnetic fields are computed inside the cathode,
arc-plasma and anode using a unified MHD formulation. The
developed model is then used to study the influence of different
helium-argon gas mixtures on both the energy transferred to the
workpiece and the time evolution of the weld pool dimensions. It is
found that the addition of helium to argon increases the heat flux
density on the weld axis by a factor that can reach 6.5. This induces
an increase in the weld pool depth by a factor of 3. It is also found
that the addition of only 10% of argon to helium decreases
considerably the weld pool depth, which is due to the electrical
conductivity of the mixture that increases significantly when argon is
added to helium.
Abstract: Ultrathin (UTD) and Nanoscale (NSD) SOI-MOSFET devices, sharing a similar W/L but with a channel thickness of 46nm and 1.6nm respectively, were fabricated using a selective “gate recessed” process on the same silicon wafer. The electrical transport characterization at room temperature has shown a large difference between the two kinds of devices and has been interpreted in terms of a huge unexpected series resistance. Electrical characteristics of the Nanoscale device, taken in the linear region, can be analytically derived from the ultrathin device ones. A comparison of the structure and composition of the layers, using advanced techniques such as Focused Ion Beam (FIB) and High Resolution TEM (HRTEM) coupled with Energy Dispersive X-ray Spectroscopy (EDS), contributes an explanation as to the difference of transport between the devices.
Abstract: A method and apparatus for noninvasive measurement
of blood glucose concentration based on transilluminated laser beam
via the Index Finger has been reported in this paper. This method
depends on atomic gas (He-Ne) laser operating at 632.8nm
wavelength. During measurement, the index finger is inserted into the
glucose sensing unit, the transilluminated optical signal is converted
into an electrical signal, compared with the reference electrical
signal, and the obtained difference signal is processed by signal
processing unit which presents the results in the form of blood
glucose concentration. This method would enable the monitoring
blood glucose level of the diabetic patient continuously, safely and
noninvasively.
Abstract: The atmospheric pressure plasma torch with a direct
current arc discharge stabilized by water vapor vortex was
experimentally investigated. Overheated up to 450K water vapor was
used as plasma forming gas. Plasma torch design is one of the most
important factors leading to a stable operation of the device. The
electrical and thermal characteristics of the plasma torch were
determined during the experimental investigations. The design and
the basic characteristics of the water vapor plasma torch are presented
in the paper.
Plasma torches with the electric arc stabilized by water vapor
vortex provide special performance characteristics in some plasma
processing applications such as thermal plasma neutralization and
destruction of organic wastes enabling to extract high caloric value
synthesis gas as by-product of the process. Syngas could be used as a
surrogate fuel partly replacing the dependence on the fossil fuels or
used as a feedstock for hydrogen, methanol production.
Abstract: In this paper, a new efficient method for load balancing in low voltage distribution systems is presented. The proposed method introduces an improved Leap-frog method for optimization. The proposed objective function includes the difference between three phase currents, as well as two other terms to provide the integer property of the variables; where the latter are the status of the connection of loads to different phases. Afterwards, a new algorithm is supplemented to undertake the integer values for the load connection status. Finally, the method is applied to different parts of Tabriz low voltage network, where the results have shown the good performance of the proposed method.
Abstract: The increase in energy demand has raised concerns
over adverse impacts on the environment from energy generation. It
is important to understand the status of energy consumption for
institutions such as Curtin Sarawak to ensure the sustainability of
energy usage, and also to reduce its costs. In this study, a preliminary
audit framework was developed and was conducted around the
Malaysian campus to obtain information such as the number and
specifications of electrical appliances, built-up area and ambient
temperature to understand the relationship of these factors with
energy consumption. It was found that the number and types of
electrical appliances, population and activities in the campus
impacted the energy consumption of Curtin Sarawak directly.
However, the built-up area and ambient temperature showed no clear
correlation with energy consumption. An investigation of the diurnal
and seasonal energy consumption of the campus was also carried out.
From the data, recommendations were made to improve the energy
efficiency of the campus.
Abstract: The draw solute separation process in Forward
Osmosis desalination was simulated in Aspen Plus chemical process
modeling software, to estimate the energy consumption and compare
it with other desalination processes, mainly the Reverse Osmosis
process which is currently most prevalent. The electrolytic chemistry
for the system was retrieved using the Elec – NRTL property method
in the Aspen Plus database. Electrical equivalent of energy required
in the Forward Osmosis desalination technique was estimated and
compared with the prevalent desalination techniques.
Abstract: In this paper, we present a vertical nanowire thin film transistor with gate-all-around architecture, fabricated using CMOS compatible processes. A novel method of fabricating polysilicon vertical nanowires of diameter as small as 30 nm using wet-etch is presented. Both n-type and p-type vertical poly-silicon nanowire transistors exhibit superior electrical characteristics as compared to planar devices. On a poly-crystalline nanowire of 30 nm diameter, high Ion/Ioff ratio of 106, low drain-induced barrier lowering (DIBL) of 50 mV/V, and low sub-threshold slope SS~100mV/dec are demonstrated for a device with channel length of 100 nm.
Abstract: Samples of CoFe2-xCrxO4 where x varies from 0.0 to 0.5 were prepared by co-precipitation route. These samples were sintered at 750°C for 2 hours. These particles were characterized by X-ray diffraction (XRD) at room temperature. The FCC spinel structure was confirmed by XRD patterns of the samples. The crystallite sizes of these particles were calculated from the most intense peak by Scherrer formula. The crystallite sizes lie in the range of 37-60 nm. The lattice parameter was found decreasing upon substitution of Cr. DC electrical resistivity was measured as a function of temperature. The room temperature thermoelectric power was measured for the prepared samples. The magnitude of Seebeck coefficient depends on the composition and resistivity of the samples.