Abstract: The sand production problem has led researchers into making various attempts to understand the phenomenon. The generally accepted concept is that the occurrence of sanding is due to the in-situ stress conditions and the induced changes in stress that results in the failure of the reservoir sandstone during hydrocarbon production from wellbores. By using a hypothetical cased (perforated) well, an approach to the problem is presented here by using Finite Element numerical modelling techniques. In addition to the examination of the erosion problem, the influence of certain key parameters is studied in order to ascertain their effect on the failure and subsequent erosion process. The major variables investigated include: drawdown, perforation depth, and the erosion criterion. Also included is the determination of the optimal mud pressure for given operational and reservoir conditions. The improved understanding between parameters enables the choice of optimal values to minimize sanding during oil production.
Abstract: Scale Time Offset Robust Modulation (STORM) [1]–
[3] is a high bandwidth waveform design that adds time-scale
to embedded reference modulations using only time-delay [4]. In
an environment where each user has a specific delay and scale,
identification of the user with the highest signal power and that
user-s phase is facilitated by the STORM processor. Both of these
parameters are required in an efficient multiuser detection algorithm.
In this paper, the STORM modulation approach is evaluated with
a direct sequence spread quadrature phase shift keying (DS-QPSK)
system. A misconception of the STORM time scale modulation is that
a fine temporal resolution is required at the receiver. STORM will
be applied to a QPSK code division multiaccess (CDMA) system
by modifying the spreading codes. Specifically, the in-phase code
will use a typical spreading code, and the quadrature code will
use a time-delayed and time-scaled version of the in-phase code.
Subsequently, the same temporal resolution in the receiver is required
before and after the application of STORM. In this paper, the bit error
performance of STORM in a synchronous CDMA system is evaluated
and compared to theory, and the bit error performance of STORM
incorporated in a single user WCDMA downlink is presented to
demonstrate the applicability of STORM in a modern communication
system.
Abstract: The localized corrosion behavior of laser surface
melted 304L austenitic stainless steel was studied by
potentiodynamic polarization test. The extent of improvement in
corrosion resistance was governed by the preferred orientation and
the percentage of delta ferrite present on the surface of the laser
melted sample. It was established by orientation imaging microscopy
that the highest pitting potential value was obtained when grains were
oriented in the most close- packed [101] direction compared to the
random distribution of the base metal and other laser surface melted
samples oriented in [001] direction. The sample with lower
percentage of ferrite had good pitting resistance.
Abstract: The proof of concept experiments were conducted to
determine the feasibility of using small amounts of Dissolved
Sulphur (DS) from the gaseous phase to precipitate platinum ions in
chloride media. Two sets of precipitation experiments were
performed in which the source of sulphur atoms was either a
thiosulphate solution (Na2S2O3) or a sulphur dioxide gas (SO2). In
liquid-liquid (L-L) system, complete precipitation of Pt was achieved
at small dosages of Na2S2O3 (0.01 – 1.0 M) in a time interval of 3-5
minutes. On the basis of this result, gas absorption tests were carried
out mainly to achieve sulphur solubility equivalent to 0.018 M. The
idea that huge amounts of precious metals could be recovered
selectively from their dilute solutions by utilizing the waste SO2
streams at low pressure seemed attractive from the economic and
environmental point of views. Therefore, mass transfer characteristics
of SO2 gas associated with reactive absorption across the gas-liquid
(G-L) interface were evaluated under different conditions of pressure
(0.5 – 2 bar), solution temperature ranges from 20 – 50 oC and acid
strength (1 – 4 M, HCl). This paper concludes with information about
selective precipitation of Pt in the presence of cations (Fe2+, Co2+,
and Cr3+) in a CSTR and recommendation to scale up laboratory data
to industrial pilot scale operations.
Abstract: In recent years, most of the regions in the world are
exposed to degradation and erosion caused by increasing
population and over use of land resources. The understanding of
the most important factors on soil erosion and sediment yield are
the main keys for decision making and planning. In this study, the
sediment yield and soil erosion were estimated and the priority of
different soil erosion factors used in the MPSIAC method of soil
erosion estimation is evaluated in AliAbad watershed in southwest
of Isfahan Province, Iran. Different information layers of the
parameters were created using a GIS technique. Then, a
multivariate procedure was applied to estimate sediment yield and
to find the most important factors of soil erosion in the model. The
results showed that land use, geology, land and soil cover are the
most important factors describing the soil erosion estimated by
MPSIAC model.
Abstract: In process control applications, above 90% of the
controllers are of PID type. This paper proposed a robust PI
controller with fractional-order integrator. The PI parameters were
obtained using classical Ziegler-Nichols rules but enhanced with the
application of error filter cascaded to the fractional-order PI. The
controller was applied on steam temperature process that was
described by FOPDT transfer function. The process can be classified
as lag dominating process with very small relative dead-time. The
proposed control scheme was compared with other PI controller
tuned using Ziegler-Nichols and AMIGO rules. Other PI controller
with fractional-order integrator known as F-MIGO was also
considered. All the controllers were subjected to set point change and
load disturbance tests. The performance was measured using Integral
of Squared Error (ISE) and Integral of Control Signal (ICO). The
proposed controller produced best performance for all the tests with
the least ISE index.
Abstract: In this paper, a pipelined version of genetic algorithm,
called PLGA, and a corresponding hardware platform are described.
The basic operations of conventional GA (CGA) are made pipelined
using an appropriate selection scheme. The selection operator, used
here, is stochastic in nature and is called SA-selection. This helps
maintaining the basic generational nature of the proposed pipelined
GA (PLGA). A number of benchmark problems are used to compare
the performances of conventional roulette-wheel selection and the
SA-selection. These include unimodal and multimodal functions with
dimensionality varying from very small to very large. It is seen that
the SA-selection scheme is giving comparable performances with
respect to the classical roulette-wheel selection scheme, for all the
instances, when quality of solutions and rate of convergence are considered.
The speedups obtained by PLGA for different benchmarks
are found to be significant. It is shown that a complete hardware
pipeline can be developed using the proposed scheme, if parallel
evaluation of the fitness expression is possible. In this connection
a low-cost but very fast hardware evaluation unit is described.
Results of simulation experiments show that in a pipelined hardware
environment, PLGA will be much faster than CGA. In terms of
efficiency, PLGA is found to outperform parallel GA (PGA) also.
Abstract: The feasibility of employing solar radiation for
enhanced Fenton process in degradation of combined chlorpyrifos,
cypermethrin and chlorothalonil pesticides was examined. The effect
of various operating conditions of the process on biodegradability
improvement and mineralization of the pesticides were also
evaluated. The optimum operating conditions for treatment of
aqueous solution containing 100, 50 and 250 mg L-1 chlorpyrifos
cypermethrin and chlorothalonil, respectively were observed to be
H2O2/COD molar ratio 2, H2O2/Fe2+ molar ratio 25 and pH 3. Under
the optimum operating conditions, complete degradation of the
pesticides occurred in 1 min. Biodegradability (BOD5/COD)
increased from zero to 0.36 in 60 min, and COD and TOC removal
were 74.19 and 58.32%, respectively in 60 min. Due to
mineralization of organic carbon, decrease in ammonia-nitrogen from
22 to 4.3 mg L-1 and increase in nitrate from 0.7 to 18.1 mg L-1 in
60 min were recorded. The study indicated that solar photo-Fenton
process can be used for pretreatment of chlorpyrifos, cypermethrin
and chlorothalonil pesticides in aqueous solution for further
biological treatment.
Abstract: The paper deals with calculation of the parameters of
ceramic material from a set of destruction tests of ceramic heads of
total hip joint endoprosthesis. The standard way of calculation of the
material parameters consists in carrying out a set of 3 or 4 point
bending tests of specimens cut out from parts of the ceramic material
to be analysed. In case of ceramic heads, it is not possible to cut out
specimens of required dimensions because the heads are too small (if
the cut out specimens were smaller than the normalised ones, the
material parameters derived from them would exhibit higher strength
values than those which the given ceramic material really has). On
that score, a special testing jig was made, in which 40 heads were
destructed. From the measured values of circumferential strains of the
head-s external spherical surface under destruction, the state of stress
in the head under destruction was established using the final elements
method (FEM). From the values obtained, the sought for parameters
of the ceramic material were calculated using Weibull-s weakest-link
theory.
Abstract: The characterization of κ-carrageenan could provide a
better understanding of its functions in biological, medical and
industrial applications. Chemical and physical analyses of
carrageenan from seaweeds, Euchema cottonii L., were done to offer
information on its properties and the effects of Co-60 γ-irradiation on
its thermochemical characteristics. The structural and morphological
characteristics of κ-carrageenan were determined using scanning
electron microscopy (SEM) while the composition, molecular weight
and thermal properties were determined using attenuated total
reflectance Fourier transform infrared spectroscopy (ATR-FTIR), gel
permeation chromatography (GPC), thermal gravimetric analysis
(TGA) and differential scanning calorimetry (DSC). Further chemical
analysis was done using hydrogen-1 nuclear magnetic resonance (1H
NMR) and functional characteristics in terms of biocompatibility
were evaluated using cytotoxicity test.
Abstract: We propose a decoy-pulse protocol for frequency-coded implementation of B92 quantum key distribution protocol. A direct extension of decoy-pulse method to frequency-coding scheme results in security loss as an eavesdropper can distinguish between signal and decoy pulses by measuring the carrier photon number without affecting other statistics. We overcome this problem by optimizing the ratio of carrier photon number of decoy-to-signal pulse to be as close to unity as possible. In our method the switching between signal and decoy pulses is achieved by changing the amplitude of RF signal as opposed to modulating the intensity of optical signal thus reducing system cost. We find an improvement by a factor of 100 approximately in the key generation rate using decoy-state protocol. We also study the effect of source fluctuation on key rate. Our simulation results show a key generation rate of 1.5×10-4/pulse for link lengths up to 70km. Finally, we discuss the optimum value of average photon number of signal pulse for a given key rate while also optimizing the carrier ratio.
Abstract: Tomato powder has good potential as substitute of tomato paste and other tomato products. In order to protect physicochemical properties and nutritional quality of tomato during dehydration process, investigation was carried out using different drying methods and pretreatments. Solar drier and continuous conveyor (tunnel) drier were used for dehydration where as calcium chloride (CaCl2), potassium metabisulphite (KMS), calcium chloride and potassium metabisulphite (CaCl2 +KMS), and sodium chloride (NaCl) selected for treatment.. lycopene content, dehydration ratio, rehydration ratio and non-enzymatic browning in addition to moisture, sugar and titrable acidity were studied. Results show that pre-treatment with CaCl2 and NaCl increased water removal and moisture mobility in tomato slices during drying of tomatoes. Where CaCl2 used along with KMS the NEB was recorded the least compared to other treatments and the best results were obtained while using the two chemicals in combination form. Storage studies in LDPE polymeric and metalized polyesters films showed less changes in the products packed in metallized polyester pouches and even after 6 months lycopene content did not decrease more than 20% as compared to the control sample and provide extension of shelf life in acceptable condition for 6 months. In most of the quality characteristics tunnel drier samples presented better values in comparison to solar drier.
Abstract: This paper presents a genetic algorithm based
approach for solving security constrained optimal power flow
problem (SCOPF) including FACTS devices. The optimal location of
FACTS devices are identified using an index called overload index
and the optimal values are obtained using an enhanced genetic
algorithm. The optimal allocation by the proposed method optimizes
the investment, taking into account its effects on security in terms of
the alleviation of line overloads. The proposed approach has been
tested on IEEE-30 bus system to show the effectiveness of the
proposed algorithm for solving the SCOPF problem.
Abstract: This is a study on numerical simulation of the convection-diffusion transport of a chemical species in steady flow through a small-diameter tube, which is lined with a very thin layer made up of retentive and absorptive materials. The species may be subject to a first-order kinetic reversible phase exchange with the wall material and irreversible absorption into the tube wall. Owing to the velocity shear across the tube section, the chemical species may spread out axially along the tube at a rate much larger than that given by the molecular diffusion; this process is known as dispersion. While the long-time dispersion behavior, well described by the Taylor model, has been extensively studied in the literature, the early development of the dispersion process is by contrast much less investigated. By early development, that means a span of time, after the release of the chemical into the flow, that is shorter than or comparable to the diffusion time scale across the tube section. To understand the early development of the dispersion, the governing equations along with the reactive boundary conditions are solved numerically using the Flux Corrected Transport Algorithm (FCTA). The computation has enabled us to investigate the combined effects on the early development of the dispersion coefficient due to the reversible and irreversible wall reactions. One of the results is shown that the dispersion coefficient may approach its steady-state limit in a short time under the following conditions: (i) a high value of Damkohler number (say Da ≥ 10); (ii) a small but non-zero value of absorption rate (say Γ* ≤ 0.5).
Abstract: Li1.5Al0.5Ti1.5 (PO4)3(LATP) has received much
attention as a solid electrolyte for lithium batteries. In this study, the
LATP solid electrolyte is prepared by the co-precipitation method
using Li3PO4 as a Li source. The LATP is successfully prepared and
the Li ion conductivities of bulk (inner crystal) and total (inner crystal
and grain boundary) are 1.1 × 10-3 and 1.1 × 10-4 S cm-1, respectively.
These values are comparable to the reported values, in which Li2C2O4
is used as the Li source. It is conclude that the LATP solid electrolyte
can be prepared by the co-precipitation method using Li3PO4 as the Li
source and this procedure has an advantage in mass production over
previous procedure using Li2C2O4 because Li3PO4 is lower price
reagent compared with Li2C2O4.
Abstract: Leading topic of this article is description of Lorentz
forces in the container with cuboid and cylindrical shape. Inside of
the container is an electrically conductive melt. This melt is driven by
rotating magnetic field. Input data for comparing Lorentz forces in
the container with cuboid shape were obtained from the computing
program NS-FEM3D, which uses DDS method of computing. Values
of Lorentz forces for container with cylindrical shape were obtained
from inferred analytical formula.
Abstract: Liver segmentation is the first significant process for
liver diagnosis of the Computed Tomography. It segments the liver
structure from other abdominal organs. Sophisticated filtering techniques
are indispensable for a proper segmentation. In this paper, we
employ a 3D anisotropic diffusion as a preprocessing step. While
removing image noise, this technique preserve the significant parts
of the image, typically edges, lines or other details that are important
for the interpretation of the image. The segmentation task is done
by using thresholding with automatic threshold values selection and
finally the false liver region is eliminated using 3D connected component.
The result shows that by employing the 3D anisotropic filtering,
better liver segmentation results could be achieved eventhough simple
segmentation technique is used.
Abstract: Automotive engine air-ratio plays an important role of
emissions and fuel consumption reduction while maintains
satisfactory engine power among all of the engine control variables. In
order to effectively control the air-ratio, this paper presents a model
predictive fuzzy control algorithm based on online least-squares
support vector machines prediction model and fuzzy logic optimizer.
The proposed control algorithm was also implemented on a real car for
testing and the results are highly satisfactory. Experimental results
show that the proposed control algorithm can regulate the engine
air-ratio to the stoichiometric value, 1.0, under external disturbance
with less than 5% tolerance.
Abstract: How to efficiently assign system resource to route the
Client demand by Gateway servers is a tricky predicament. In this
paper, we tender an enhanced proposal for autonomous recital of
Gateway servers under highly vibrant traffic loads. We devise a
methodology to calculate Queue Length and Waiting Time utilizing
Gateway Server information to reduce response time variance in
presence of bursty traffic.
The most widespread contemplation is performance, because
Gateway Servers must offer cost-effective and high-availability
services in the elongated period, thus they have to be scaled to meet
the expected load. Performance measurements can be the base for
performance modeling and prediction. With the help of performance
models, the performance metrics (like buffer estimation, waiting
time) can be determined at the development process.
This paper describes the possible queue models those can be
applied in the estimation of queue length to estimate the final value
of the memory size. Both simulation and experimental studies using
synthesized workloads and analysis of real-world Gateway Servers
demonstrate the effectiveness of the proposed system.
Abstract: The objective of this research is parameters optimized
of the stair shape workpiece which is cut by CNC Wire-Cut EDM
(WEDW). The experiment material is SKD-11 steel of stair-shaped
with variable height workpiece 10, 20, 30 and 40 mm. with the same
10 mm. thickness are cut by Sodick's CNC Wire-Cut EDM model
AD325L.
The experiments are designed by 3k full factorial experimental
design at 3 level 2 factors and 9 experiments with 2 replicate. The
selected two factor are servo voltage (SV) and servo feed rate (SF)
and the response is cutting thickness error. The experiment is divided
in two experiments. The first experiment determines the significant
effective factor at confidential interval 95%. The SV factor is the
significant effective factor from first result. In order to result smallest
cutting thickness error of workpieces is 17 micron with the SV value
is 46 volt. Also show that the lower SV value, the smaller different
thickness error of workpiece. Then the second experiment is done to
reduce different cutting thickness error of workpiece as small as
possible by lower SV. The second experiment result show the
significant effective factor at confidential interval 95% is the SV
factor and the smallest cutting thickness error of workpieces reduce
to 11 micron with the experiment SV value is 36 volt.