Abstract: In the present work, a study has been made on the combination of the electrical discharge machining (EDM) with ultrasonic vibrations to improve the machining efficiency. In experiments the graphite used as tool electrode and material of workpiece was AISIH13 tool steel. The parameters such as discharge peak current and pulse duration were changed to explore their effect on the material removal rate (MRR), relative tool wear ratio (TWR) and surface roughness. From the experimental result it can be seen that ultrasonic vibration of the workpiece can significantly reduces the inactive pulses and improves the stability of process. It was found that ultrasonic assisted EDM (US-EDM) is effective in attaining a high material removal rate (MRR) in finishing regime.
Abstract: TiO2/MgO composite films were prepared by coating
the magnesium acetate solution in the pores of mesoporous TiO2
films using a dip coating method. Concentrations of magnesium
acetate solution were varied in a range of 1x10-4 – 1x10-1 M. The
TiO2/MgO composite films were characterized by scanning electron
microscopy (SEM), transmission electron microscropy (TEM),
electrochemical impedance spectroscopy(EIS) , transient voltage
decay and I-V test. The TiO2 films and TiO2/MgO composite films
were immersed in a 0.3 mM N719 dye solution. The Dye-sensitized
solar cells with the TiO2/MgO/N719 structure showed an optimal
concentration of magnesium acetate solution of 1x10-3 M resulting in
the MgO film estimated thickness of 0.0963 nm and giving the
maximum efficiency of 4.85%. The improved efficiency of dyesensitized
solar cell was due to the magnesium oxide film as the wide
band gap coating decays the electron back transfer to the triiodide
electrolyte and reduce charge recombination.
Abstract: The major urban centers are all facing rapid growth is
most often associated with spreading urbanization, social status of the
car has also changed: it has become a commodity of mass
consumption. There are currently about 5 million and 260 cars in
Algeria (2008), this number increases every year 200,000 new cars.
These phenomena induce a demand for greater mobility and a
significant need for transport infrastructure. Faced with these
problems and development of the growing use of the automobile,
central governments and local authorities in charge of urban transport
issues are aware of the need to develop their urban transport systems
but often lack opportunities.
Urban Transport Plans (PDU) were born in reaction to the "culture
of automobile." Their existence in the world the '80s, however, they
had little success before laws on air and rational use of energy in 90
years does not alter substantially their content and make mandatory
their implementation in cities of over 100,000 inhabitants (Abroad)
[1].
The objective of this work is to use the tool and specifically
Geomatics techniques as decision support in the organization and
management of travel while taking into consideration the influence,
which will then translate by National Urban Transport Plan.
Abstract: Estimation of stormwater pollutants is a pre-requisite
for the protection and improvement of the aquatic environment and
for appropriate management options. The usual practice for the
stormwater quality prediction is performed through water quality
modeling. However, the accuracy of the prediction by the models
depends on the proper estimation of model parameters. This paper
presents the estimation of model parameters for a catchment water
quality model developed for the continuous simulation of stormwater
pollutants from a catchment to the catchment outlet. The model is
capable of simulating the accumulation and transportation of the
stormwater pollutants; suspended solids (SS), total nitrogen (TN) and
total phosphorus (TP) from a particular catchment. Rainfall and water
quality data were collected for the Hotham Creek Catchment (HTCC),
Gold Coast, Australia. Runoff calculations from the developed model
were compared with the calculated discharges from the widely used
hydrological models, WBNM and DRAINS. Based on the measured
water quality data, model water quality parameters were calibrated
for the above-mentioned catchment. The calibrated parameters are
expected to be helpful for the best management practices (BMPs)
of the region. Sensitivity analyses of the estimated parameters were
performed to assess the impacts of the model parameters on overall
model estimations of runoff water quality.
Abstract: This paper presents ageing experiments controlled by the evolution of junction parameters. The deterioration of the device is related to high injection effects which modified the transport mechanisms in the space charge region of the junction. Physical phenomena linked to the degradation of junction parameters that affect the devices reliability are reported and discussed. We have used the method based on numerical analysis of experimental current-voltage characteristic of the junction, in order to extract the electrical parameters. The simultaneous follow-up of the evolutions of the series resistance and of the transition voltage allow us to introduce a new parameter for reliability evaluation.
Abstract: Clean air in subway station is important to passengers. The Platform Screen Doors (PSDs) can improve indoor air quality in the subway station; however the air quality in the subway tunnel is degraded. The subway tunnel has high CO2 concentration and indoor particulate matter (PM) value. The Indoor Air Quality (IAQ) level in subway environment degrades by increasing the frequency of the train operation and the number of the train. The ventilation systems of the subway tunnel need improvements to have better air-quality. Numerical analyses might be effective tools to analyze the performance of subway twin-track tunnel ventilation systems. An existing subway twin-track tunnel in the metropolitan Seoul subway system is chosen for the numerical simulations. The ANSYS CFX software is used for unsteady computations of the airflow inside the twin-track tunnel when the train moves. The airflow inside the tunnel is simulated when one train runs and two trains run at the same time in the tunnel. The piston-effect inside the tunnel is analyzed when all shafts function as the natural ventilation shaft. The supplied air through the shafts is mixed with the pollutant air in the tunnel. The pollutant air is exhausted by the mechanical ventilation shafts. The supplied and discharged airs are balanced when only one train runs in the twin-track tunnel. The pollutant air in the tunnel is high when two trains run simultaneously in opposite direction and all shafts functioned as the natural shaft cases when there are no electrical power supplies in the shafts. The remained pollutant air inside the tunnel enters into the station platform when the doors are opened.
Abstract: The Platform Screen Doors improve Indoor Air Quality
(IAQ) in the subway station; however, and the air quality is degraded
in the subway tunnel. CO2 concentration and indoor particulate matter
value are high in the tunnel. The IAQ level in subway tunnel degrades
by increasing the train movements. Air-curtain installation reduces
dusts, particles and moving toxic smokes and permits traffic by
generating virtual wall. The ventilation systems of the subway tunnel
need improvements to have better air-quality. Numerical analyses
might be effective tools analyze the flowfield inside the air-curtain
installed subway tunnel. The ANSYS CFX software is used for steady
computations of the airflow inside the tunnel. The single-track subway
tunnel has the natural shaft, the mechanical shaft, and the PSDs
installed stations. The height and width of the tunnel are 6.0 m and 4.0
m respectively. The tunnel is 400 m long and the air-curtain is installed
at the top of the tunnel. The thickness and the width of the air-curtain
are 0.08 m and 4 m respectively. The velocity of the air-curtain
changes between 20 - 30 m/s. Three cases are analyzed depending on
the installing location of the air-curtain. The discharged-air through
the natural shafts increases as the velocity of the air-curtain increases
when the air-curtain is installed between the mechanical and the
natural shafts. The pollutant-air is exhausted by the mechanical and the
natural shafts and remained air is pushed toward tunnel end. The
discharged-air through the natural shaft is low when the air-curtain
installed before the natural shaft. The mass flow rate decreases in the
tunnel after the mechanical shaft as the air-curtain velocity increases.
The computational results of the air-curtain installed tunnel become
basis for the optimum design study. The air-curtain installing location
is chosen between the mechanical and the natural shafts. The velocity
of the air-curtain is fixed as 25 m/s. The thickness and the blowing
angles of the air-curtain are the design variables for the optimum
design study. The object function of the design optimization is
maximizing the discharged air through the natural shaft.
Abstract: The research study is carried out to determine the efficiency of the Biofilm sewage treatment plant which is located at the Engineering Complex-s. Wastewater analyses have been carried out at the Environmental Engineering laboratory to study the six parameters: Biochemical Oxygen Demand BOD, Chemical Oxygen Demand COD l, and Total Suspended Solids TSS, Ammoniac Nitrogen NH3-N and Phosphorous P which have been selected to determine the wastewater quality. The plant was designed to treat 750 Pe (population equivalent) at hydraulic retention time of 5 hours in the aerobic zone. The results show that Biofilm wastewater treatment plant was able to treat sewage successfully at different flow condition. The discharge has fulfilled the Malaysia Environmental of Standard A water quality. The achieved BOD removal is more than 85%, COD is more than 80%, TSS is more than 80%, NH3-N is more than 70%, and P was more than 70%. The Biofilm system provides a very efficient process for sewage treatment and it is compact in structure thus minimizes the required land area.
Abstract: Gradual patterns have been studied for many years as
they contain precious information. They have been integrated in
many expert systems and rule-based systems, for instance to reason
on knowledge such as “the greater the number of turns, the greater
the number of car crashes”. In many cases, this knowledge has been
considered as a rule “the greater the number of turns → the greater
the number of car crashes” Historically, works have thus been
focused on the representation of such rules, studying how implication
could be defined, especially fuzzy implication. These rules were
defined by experts who were in charge to describe the systems they
were working on in order to turn them to operate automatically. More
recently, approaches have been proposed in order to mine databases
for automatically discovering such knowledge. Several approaches
have been studied, the main scientific topics being: how to determine
what is an relevant gradual pattern, and how to discover them as
efficiently as possible (in terms of both memory and CPU usage).
However, in some cases, end-users are not interested in raw level
knowledge, and are rather interested in trends. Moreover, it may be
the case that no relevant pattern can be discovered at a low level of
granularity (e.g. city), whereas some can be discovered at a higher
level (e.g. county). In this paper, we thus extend gradual pattern
approaches in order to consider multiple level gradual patterns. For
this purpose, we consider two aggregation policies, namely
horizontal and vertical.
Abstract: Exploding concentrated underwater charges to
damage underwater structures such as ship hulls is a part of naval
warfare strategies. Adding small amounts of foreign particles (like
clay or silica) of nanosize significantly improves the engineering
properties of the polymers. In the present work the clay in terms 1, 2
and 3 percent by weight was surface treated with a suitable silane
agent. The hybrid nanocomposite was prepared by the hand lay-up
technique. Mathematical regression models have been employed for
theoretical prediction. This will result in considerable savings in terms of project time, effort and cost.
Abstract: This paper presents the experimental results of
discharge current phenomena on various humidity, temperature,
pressure and pollutant conditions of epoxy resin specimen. The
leakage distance of specimen was 3 cm, that it was supplied by high
voltage. The polluted condition was given with NaCl artificial
pollutant. The conducted measurements were discharge current and
applied voltage. The specimen was put in a hermetically sealed
chamber, and the current waveforms were analyzed with FFT.
The result indicated that on discharge condition, the fifth
harmonics still had dominant, rather than third one. The third
harmonics tent to be appeared on low pressure heavily polluted
condition, and followed by high humidity heavily polluted condition.
On the heavily polluted specimen, the peaks discharge current points
would be high and more frequent. Nevertheless, the specimen still
had capacitive property. Besides that, usually discharge current
points were more frequent. The influence of low pressure was still
dominant to be easier to discharge. The non-linear property would be
appear explicitly on low pressure and heavily polluted condition.
Abstract: Non-viral gene carriers composed of biodegradable
polymers or lipids have been considered as a safer alternative for gene
carriers over viral vectors. We have developed multi-functional
nano-micelles for both drug and gene delivery application.
Polyethyleneimine (PEI) was modified by grafting stearic acid (SA)
and formulated to polymeric micelles (PEI-SA) with positive surface
charge for gene and drug delivery. Our results showed that PEI-SA
micelles provided high siRNA binding efficiency. In addition, siRNA
delivered by PEI-SA carriers also demonstrated significantly high
cellular uptake even in the presence of serum proteins. The
post-transcriptional gene silencing efficiency was greatly improved by
the polyplex formulated by 10k PEI-SA/siRNA. The amphiphilic
structure of PEI-SA micelles provided advantages for multifunctional
tasks; where the hydrophilic shell modified with cationic charges can
electrostatically interact with DNA or siRNA, and the hydrophobic
core can serve as payloads for hydrophobic drugs, making it a
promising multifunctional vehicle for both genetic and chemotherapy
application.
Abstract: Hierarchical high-level PNs (HHPNs) with time
versions are a useful tool to model systems in a variety of application
domains, ranging from logistics to complex workflows. This paper
addresses an application domain which is receiving more and more
attention: procedure that arranges the final inpatient charge in
payment-s office and their management. We shall prove that Petri net
based analysis is able to improve the delays during the procedure, in
order that inpatient charges could be more reliable and on time.
Abstract: The study of interaction among the grain, moisture,
and the surrounding space (air) is key to understanding the graindrying
process. In Iran, rice (mostly Indica type) is dried by flat
bed type dryer until the final MC reaches to 6 to 8%. The
experiments were conducted to examine the effect of application of
discharge fan with different heights of paddy on the drying
efficiency. Experiments were designed based on two different
configurations of the drying methods; with and without discharge
fan with three different heights of paddy including; 5, 10, and 15
cm. The humid heated air will be going out immediately by the
suction of discharge fan. The drying time is established upon the
average final MC to achieve about 8%. To save energy and reduce
the drying time, the distribution of temperature between layers
should be fast and uniform with minimum difference; otherwise
the difference of MC gradient between layers will be high and will
induce grain breakage. The difference of final MC between layers
in the two methods was 48-73%. The steady state of temperature
between the two methods has saved time in the range of 10-20%,
and the efficiency of temperature distribution increased 17-26% by
the use of discharge fan.
Abstract: This paper applies fuzzy AHP to evaluate the service
quality of online auction. Service quality is a composition of various
criteria. Among them many intangible attributes are difficult to
measure. This characteristic introduces the obstacles for respondents
on reply in the survey. So as to overcome this problem, we invite
fuzzy set theory into the measurement of performance and use AHP in
obtaining criteria. We found the most concerned dimension of service
quality is Transaction Safety Mechanism and the least is Charge Item.
Other criteria such as information security, accuracy and information
are too vital.
Abstract: The designing of charge pump with high gain Op-
Amp is a challenging task for getting faithful response .Design of
high performance phase locked loop require ,a design of high
performance charge pump .We have designed a operational amplifier
for reducing the error caused by high speed glitch in a transistor and
mismatch currents . A separate Op-Amp has designed in 180 nm
CMOS technology by CADENCE VIRTUOSO tool. This paper
describes the design of high performance charge pump for GHz
CMOS PLL targeting orthogonal frequency division multiplexing
(OFDM) application. A high speed low power consumption Op-Amp
with more than 500 MHz bandwidth has designed for increasing the
speed of charge pump in Phase locked loop.
Abstract: An organic bulk heterojunction (BHJ) was fabricated using a blended film containing Copper (II) tetrakis(4-acumylphenoxy) phthalocyanine (Tc-CuPc) along with [6,6]-Phenyl C61 butyric acid methyl ester (PCBM). Weight ratio between Tc-CuPc and PCBM was 1:1. The electrical properties of Tc-CuPc: PCBM BHJ were examined. Rectifying nature of the BHJ was displayed by current-voltage (I-V) curves, recorded in dark and at various temperatures. At low voltages, conduction was ohmic succeeded by space-charge limiting current (SCLC) conduction at higher voltages in which exponential trap distribution was dominant. Series resistance, shunt resistance, ideality factor, effective barrier height and mobility at room temperature were found to be 526 4, 482 k4, 3.7, 0.17 eV and 2×10-7 cm2V-1s-1 respectively. Temperature effect towards different BHJ parameters was observed under dark condition.
Abstract: The direct discharge of palm oil mill effluent (POME) wastewater causes serious environmental pollution due to its high chemical oxygen demand (COD) and biochemical oxygen demand (BOD). Traditional ways for POME treatment have both economical and environmental disadvantages. In this study, a membrane anaerobic system (MAS) was used as an alternative, cost effective method for treating POME. Six steady states were attained as a part of a kinetic study that considered concentration ranges of 8,220 to 15,400 mg/l for mixed liquor suspended solids (MLSS) and 6,329 to 13,244 mg/l for mixed liquor volatile suspended solids (MLVSS). Kinetic equations from Monod, Contois and Chen & Hashimoto were employed to describe the kinetics of POME treatment at organic loading rates ranging from 2 to 13 kg COD/m3/d. throughout the experiment, the removal efficiency of COD was from 94.8 to 96.5% with hydraulic retention time, HRT from 400.6 to 5.7 days. The growth yield coefficient, Y was found to be 0.62gVSS/g COD the specific microorganism decay rate was 0.21 d-1 and the methane gas yield production rate was between 0.25 l/g COD/d and 0.58 l/g COD/d. Steady state influent COD concentrations increased from 18,302 mg/l in the first steady state to 43,500 mg/l in the sixth steady state. The minimum solids retention time, which was obtained from the three kinetic models ranged from 5 to 12.3 days. The k values were in the range of 0.35 – 0.519 g COD/ g VSS • d and values were between 0.26 and 0.379 d-1. The solids retention time (SRT) decreased from 800 days to 11.6 days. The complete treatment reduced the COD content to 2279 mg/l equivalent to a reduction of 94.8% reduction from the original.
Abstract: Behavior of turbulent jet is relying on jet parameters,
environmental and geometric parameters. In this research, it has
attempt to Study effect of jet parameters of internal angle on
maximum effective length and velocity on centerline from nozzle
experimentally. Toward this end, four internal angles 30, 45, 60 and
90-degree are considered for this study in a flume with 600cm as
long, 100cm as high and 150cm in width. Various discharges were
used to evaluate effective length for a wide range of densimetric
Froude numbers F0, from 17.9 to 39.4 that is defined at the nozzle. As
a result, It is revealed that both velocity on centerline and effective
length decreases when nozzle angle decreased from 90° to 30°. The
results show that, for all range of Fr0 the Um/U0 ratio for nozzle with
α=90° on centerline increases 20% - 27% than nozzle with α=30° that
has lowest velocity on centerline than other nozzle.
Abstract: A 2.4GHz (RF) down conversion Gilbert Cell mixer,
implemented in a 0.18-μm CMOS technology with a 1.8V supply, is
presented. Current bleeding (charge injection) technique has been
used to increase the conversion gain and the linearity of the mixer.
The proposed mixer provides 10.75 dB conversion gain ( C G ) with
14.3mw total power consumption. The IIP3 and 1-dB compression
point of the mixer are 8dbm and -4.6dbm respectively, at 300 MHz
IF frequencies. Comparing the current design against the
conventional mixer design, demonstrates better performance in the
conversion gain, linearity, noise figure and port-to-port isolation.