Abstract: Load balancing is the process of improving the
performance of a parallel and distributed system through a
redistribution of load among the processors [1] [5]. In this paper we
present the performance analysis of various load balancing
algorithms based on different parameters, considering two typical
load balancing approaches static and dynamic. The analysis indicates
that static and dynamic both types of algorithm can have
advancements as well as weaknesses over each other. Deciding type
of algorithm to be implemented will be based on type of parallel
applications to solve. The main purpose of this paper is to help in
design of new algorithms in future by studying the behavior of
various existing algorithms.
Abstract: In this paper, we consider Wiener nonlinear model for solid oxide fuel cell (SOFC). The Wiener model of the SOFC consists of a linear dynamic block and a static output non-linearity followed by the block, in which linear part is approximated by state-space model and the nonlinear part is identified by a polynomial form. To control the SOFC system, we have to consider various view points such as operating conditions, another constraint conditions, change of load current and so on. A change of load current is the significant one of these for good performance of the SOFC system. In order to keep the constant stack terminal voltage by changing load current, the nonlinear model predictive control (MPC) is proposed in this paper. After primary control method is designed to guarantee the fuel utilization as a proper constant, a nonlinear model predictive control based on the Wiener model is developed to control the stack terminal voltage of the SOFC system. Simulation results verify the possibility of the proposed Wiener model and MPC method to control of SOFC system.
Abstract: In this study, a 3D combustion chamber was simulated
using FLUENT 6.32. Aims to obtain accurate information about the
profile of the combustion in the furnace and also check the effect of
oxygen enrichment on the combustion process. Oxygen enrichment is
an effective way to reduce combustion pollutant. The flow rate of air
to fuel ratio is varied as 1.3, 3.2 and 5.1 and the oxygen enriched
flow rates are 28, 54 and 68 lit/min. Combustion simulations
typically involve the solution of the turbulent flows with heat
transfer, species transport and chemical reactions. It is common to
use the Reynolds-averaged form of the governing equation in
conjunction with a suitable turbulence model. The 3D Reynolds
Averaged Navier Stokes (RANS) equations with standard k-ε
turbulence model are solved together by Fluent 6.3 software. First
order upwind scheme is used to model governing equations and the
SIMPLE algorithm is used as pressure velocity coupling. Species
mass fractions at the wall are assumed to have zero normal
gradients.Results show that minimum mole fraction of CO2 happens
when the flow rate ratio of air to fuel is 5.1. Additionally, in a fixed
oxygen enrichment condition, increasing the air to fuel ratio will
increase the temperature peak. As a result, oxygen-enrichment can
reduce the CO2 emission at this kind of furnace in high air to fuel
rates.
Abstract: This paper reports on the results of experimental
investigations of flash evaporation from superheated jet issues
vertically upward from a round straight nozzle of 81.3 mm diameter.
For the investigated range of jet superheat degree and velocity, it was
shown that flash evaporation enhances with initial temperature
increase. Due to the increase of jet inertia and subsequently the delay
of jet shattering, increase of jet velocity was found to result in
increase of evaporation "delay period". An empirical equation
predicts the jet evaporation completion height was developed, this
equation is thought to be useful in designing the flash evaporation
chamber. In attempts for enhancement of flash evaporation, use of
steel wire mesh located at short distance downstream was found
effective with no consequent pressure drop.
Abstract: Aroma forming volatiles are important components of
fermented beverages. The aim of current research is to evaluate the
volatile compounds and phenolic compounds of commercial ciders.
Volatile aroma compounds and TPC of seven commercial ciders
were determined. Extraction of aroma compounds was performed
using solid phase microextraction (DVB/Car/PDMS fibre). Analysis
of volatile aroma compounds was made using a Perkin Elmer Clarus
500 GC/MS. Total phenol content (TPC) was determined according
to the Folin-Ciocalteu spectrophotometric method and results were
expressed as gallic acid equivalents. The highest volatile compounds
were in apple ciders with pear flavor. The highest TPC and lower
content of volatile compounds were detected in French ciders.
Abstract: Groundwater resources in Arsanjan plain provide
water for agriculture, industry, and human consumption. Continued
agricultural development in this area needs to additional groundwater
resources for, particularly during of drought periods, and effects on
the quantity and quality of ground water available. The purpose of
this study is to evaluate water level changes in the aquifer of
Arsanjan plain in the Fars province in order to determine the areas of
greatest depletion and the causes of depletion. In this plain, farmers
and other users are pumping groundwater faster than its natural
replenishment rate, causing a continuous drop in groundwater tables
and depletion of this resource. In this research variation of
groundwater level, their effects and ways to help control groundwater
levels in aquifer of the Arsanjan plains were evaluated .Excessive
exploitation of groundwater in this aquifer caused the groundwater
levels fall too fast or to unacceptable levels. The average drawdown
of the groundwater level in this plain were 19.66 meters during
1996 to 2003.
Abstract: In order to realize long-lived electric propulsion
systems, we have been investigating an electrodeless plasma thruster.
In our concept, a helicon plasma is accelerated by the magnetic nozzle
for the thrusts production. In addition, the electromagnetic thrust can
be enhanced by the additional radio-frequency rotating electric field
(REF) power in the magnetic nozzle. In this study, a direct
measurement of the electromagnetic thrust and a probe measurement
have been conducted using a laboratory model of the thruster under the
condition without the REF power input. Fromthrust measurement, it is
shown that the thruster produces a sub-milli-newton order
electromagnetic thrust force without the additional REF power. The
thrust force and the density jump are observed due to the discharge
mode transition from the inductive coupled plasma to the helicon wave
excited plasma. The thermal thrust is theoretically estimated, and the
total thrust force, which is a sum of the electromagnetic and the
thermal thrust force and specific impulse are calculated to be up to 650
μN (plasma production power of 400 W, Ar gas mass flow rate of 1.0
mg/s) and 210 s (plasma production power of 400 W, Ar gas mass flow
rate of 0.2 mg/s), respectively.
Abstract: The fast technology and economic growth in China has
attracted global attention in its tourism development. This study makes
an effort on investigating China-s online tourism market and the
Chinese online travelers- perceptions of hotel websites. The findings
are expected to better understand Chinese customers- online
preference and identified the differences among online travelers from
different regions in the country. Empirical findings showed online
reservation information is the most important factor to Chinese
customers, and tourists from different regions of China have
perception difference on user-friendly factor. The findings benefit
hoteliers from understanding their websites development and
formulating more appropriate online strategies to meet the
requirements of Chinese travelers.
Abstract: This paper examines the problem of designing robust H controllers for for HIV/AIDS infection system with dual drug dosages described by a Takagi-Sugeno (S) fuzzy model. Based on a linear matrix inequality (LMI) approach, we develop an H controller which guarantees the L2-gain of the mapping from the exogenous input noise to the regulated output to be less than some prescribed value for the system. A sufficient condition of the controller for this system is given in term of Linear Matrix Inequalities (LMIs). The effectiveness of the proposed controller design methodology is finally demonstrated through simulation results. It has been shown that the anti-HIV vaccines are critically important in reducing the infected cells.
Abstract: A closed-loop controlled wireless power transmission circuit block for implantable biomedical applications is described in this paper. The circuit consists of one front-end rectifier, power management sub-block including bandgap reference and low drop-out regulators (LDOs) as well as transmission power detection / feedback circuits. Simulation result shows that the front-end rectifier achieves 80% power efficiency with 750-mV single-end peak-to-peak input voltage and 1.28-V output voltage under load current of 4 mA. The power management block can supply 1.8mA average load current under 1V consuming only 12μW power, which is equivalent to 99.3% power efficiency. The wireless power transmission block described in this paper achieves a maximum power efficiency of 80%. The wireless power transmission circuit block is designed and implemented using UMC 65-nm CMOS/RF process. It occupies 1 mm × 1.2 mm silicon area.
Abstract: This study was carried out to determine the feedback from the primary school headmasters on in-service training activities. 384 primary school headmasters were asked to give feedback on the in-service training facilities organized by the Ministry of Education through an open –ended question. The study group was formed by 359 primary school headmasters who attended “Management Skills" seminars which were organized in March, April and May in the extent of 2006 In-service Training Facilities Plan by the Ministry of Education and were also volunteers to give feedback on the inservice training activities. The qualitative research method was used in the analysis of the data since the primary school headmasters gave written feedback on the in-service training activities. Having analyzed the feedback, certain categories were formed by coding it. Certain frequencies and percentages were determined according to the codes. It was made obvious that the primary school headmasters benefitted from those facilities by sharing their experiences, problems and their possible solutions mutually
Abstract: Functional Magnetic Resonance Imaging(fMRI) is a
noninvasive imaging technique that measures the hemodynamic
response related to neural activity in the human brain. Event-related
functional magnetic resonance imaging (efMRI) is a form of
functional Magnetic Resonance Imaging (fMRI) in which a series of
fMRI images are time-locked to a stimulus presentation and averaged
together over many trials. Again an event related potential (ERP) is a
measured brain response that is directly the result of a thought or
perception. Here the neuronal response of human visual cortex in
normal healthy patients have been studied. The patients were asked
to perform a visual three choice reaction task; from the relative
response of each patient corresponding neuronal activity in visual
cortex was imaged. The average number of neurons in the adult
human primary visual cortex, in each hemisphere has been estimated
at around 140 million. Statistical analysis of this experiment was
done with SPM5(Statistical Parametric Mapping version 5) software.
The result shows a robust design of imaging the neuronal activity of
human visual cortex.
Abstract: This study examines the influence of information
transparency and corporate governance on purchase directors and
officers liability (D&O) insurance decisions. The results show that
companies with greater information transparency have significant
demand for D&O insurance. Greater transparency in voluntary
disclosures is significantly and positively associated with demand for
insurance, indicating that increasing the degree of information
disclosure reduces information asymmetry for insurers, which
stimulates their willingness to provide greater protection.
Analysis of insured and uninsured subsamples indicates that
uninsured companies have superior corporate governance compared to
insured companies. Although insured companies tend to have weaker
corporate governance structures, they appoint Big 4 firms or industry
experts to compensate for the weakness of their corporate governance.
Empirical results indicate that purchasing D&O insurance can
strengthen external corporate governance and increase companies’
willingness to voluntarily provide more transparent information.
Abstract: The main aim of this work is to develop a model of hydrogen sulfide (H2S) separation from natural gas by using membrane separation technology. The model is developed by incorporating three diffusion mechanisms which are Knudsen, viscous and surface diffusion towards membrane selectivity and permeability. The findings from the simulation result shows that the permeability of the gas is dependent toward the pore size of the membrane, operating pressure, operating temperature as well as feed composition. The permeability of methane has the highest value for Poly (1-trimethylsilyl-1-propyne ) PTMSP membrane at pore size of 0.1nm and decreasing toward a minimum peak at pore range 1 to 1.5 nm as pore size increased before it increase again for pore size is greater than 1.5 nm. On the other hand, the permeability of hydrogen sulfide is found to increase almost proportionally with the increase of membrane pore size. Generally, the increase of pressure will increase the permeability of gas since more driving force is provided to the system while increasing of temperature would decrease the permeability due to the surface diffusion drop off effect. A corroboration of the simulation result also showed a good agreement with the experimental data.
Abstract: This paper presents the experimental results of
leakage current waveforms which appears on porcelain insulator
surface due to existence of artificial pollutants. The tests have been
done using the chemical compounds of NaCl, Na2SiO3, H2SO4, CaO,
Na2SO4, KCl, Al2SO4, MgSO4, FeCl3, and TiO2. The insulator
surface was coated with those compounds and dried. Then, it was
tested in the chamber where the high voltage was applied. Using
correspondence analysis, the result indicated that the fundamental
harmonic of leakage current was very close to the applied voltage
and third harmonic leakage current was close to the yielded leakage
current amplitude. The first harmonic power was correlated to first
harmonic amplitude of leakage current, and third harmonic power
was close to third harmonic one. The chemical compounds of H2SO4
and Na2SiO3 affected to the power factor of around 70%. Both are the
most conductive, due to the power factor drastically increase among
the chemical compounds.
Abstract: Client expectations and preferences about therapy
represent an important area of investigation as research shows they
are linked to engagement in therapy and therapy outcomes. Studies
examining young people-s expectations and preferences of therapy
remain a neglected area of research. The present study explored what
expectations and preferences young people seeking professional help
held regarding: their role as a client, their therapist-s role, their
therapeutic outcomes, and the processes of therapy. Gender and age
differences were also examined. Participants included 188 young
people aged 12-25 who completed a survey while attending their
initial session at a youth mental health service. Data were analysed
using quantitative methods. Results found the young people held
significantly more pessimistic expectations around therapy when
compared to what they had wanted therapy to be like. Few age and
gender differences were found. Results highlight the importance of a
collaborative therapy approach when working with young people.
Abstract: Let G be an arbitrary group with identity e and let
R be a G-graded ring. In this paper we define graded semiprime submodules of a graded R-moduleM and we give a number of results
concerning such submodules. Also, we extend some results of graded semiprime submoduls to graded weakly semiprime submodules.
Abstract: Experimental investigation has been carried out
towards understanding the complex fluid dynamics involved in the
interaction of vortical structures with zero pressure gradient boundary
layer. A laminar boundary layer is produced on the flat plate placed
in the water flume and the synthetic jet actuator is deployed on top of
the plate at a definite distance from the leading edge. The synthetic
jet actuator has been designed in such a way that the to and fro
motion of the diaphragm is maneuvered at will by varying the
operating parameters to produce the typical streamwise vortical
structures namely hairpin and tilted vortices. PIV measurements are
made on the streamwise plane normal to the plate to evaluate their
interaction with the near wall fluid.
Abstract: An improved processing description to be employed in biosonar signal processing in a cochlea model is proposed and examined. It is compared to conventional models using a modified discrimination analysis and both are tested. Their performances are evaluated with echo data captured from natural targets (trees).Results indicate that the phase characteristics of low-pass filters employed in the echo processing have a significant effect on class separability for this data.
Abstract: Our research aims at helping the tutor on line to
evaluate the student-s cognitive processes. The student is a learner in
French as a Second Language who studies an on-line socio-cognitive
scenario in written communication. In our method, these cognitive
processes are defined. For that, the language abilities and learning
tasks are associated to cognitive operation. Moreover, the found
cognitive processes are named with specific terms. The result was to
create an instrumental pattern to question the learner about the
cognitive processes used to build an item of written comprehension.
Our research follows the principles of the third historical generation
of studies on the cognitive activity of the text comprehension. The
strength of our instrumental pattern stands in the precision and the
logical articulation of the questions to the learner. However, the
learner-s answers can still be subjective but the precision of the
instrument restricts it.