Abstract: The high efficiency power management IC (PMIC) with switching device is presented in this paper. PMIC is controlled with PFM control method in order to have high power efficiency at high current level. Dynamic Threshold voltage CMOS (DT-CMOS) with low on-resistance is designed to decrease conduction loss. The threshold voltage of DT-CMOS drops as the gate voltage increase, resulting in a much higher current handling capability than standard MOSFET. PFM control circuits consist of a generator, AND gate and comparator. The generator is made to have 1.2MHz oscillation voltage. The DC-DC converter based on PFM control circuit and low on-resistance switching device is presented in this paper.
Abstract: The aim of this study was to determine the antimicrobial effect of Helichrysum arenarium L. essential oil in "in-vitro" condition on the growth of seven microbial species including Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Saccharomyces cereviciae, Candida albicans, Aspergillus flavus and Aspergillus parasiticus using micro-dilution method. The minimum inhibitory concentration (MIC) and minimum bactericidal or fungicidal concentration (MBC, MFC) were determined for the essential oil at ten concentrations. Finally, the sensitivity of tested microbes to essential oil of H. arenarium was investigated. Results showed that Bacillus subtilis (MIC=781.25 and MBC=6250 µg/ml) was more resistance than two other bacterial species. Among the tested yeasts, Saccharomyces cereviciae (MIC=97.65 and MFC=781.25 µg/ml) was more sensitive than Candida albicans while among the fungal species, growth of Aspergillus parasiticus inhibited at lower concentration of oil than the Aspergillus flavus. The extracted essential oil exhibited the same MIC value in the liquid medium against all fungal strains (48.82 µg/ml), while different activity against A. flavus and A. parasiticus was observed in this medium with MFC values of 6250 and 390.625µg/ml, respectively. The results of the present study indicated that Helichrysum arenarium L essential oil had significant (P
Abstract: In this paper, a backward semi-Lagrangian scheme
combined with the second-order backward difference formula
is designed to calculate the numerical solutions of nonlinear
advection-diffusion equations. The primary aims of this paper are
to remove any iteration process and to get an efficient algorithm
with the convergence order of accuracy 2 in time. In order to achieve
these objects, we use the second-order central finite difference and the
B-spline approximations of degree 2 and 3 in order to approximate
the diffusion term and the spatial discretization, respectively. For the
temporal discretization, the second order backward difference formula
is applied. To calculate the numerical solution of the starting point
of the characteristic curves, we use the error correction methodology
developed by the authors recently. The proposed algorithm turns out
to be completely iteration free, which resolves the main weakness
of the conventional backward semi-Lagrangian method. Also, the
adaptability of the proposed method is indicated by numerical
simulations for Burgers’ equations. Throughout these numerical
simulations, it is shown that the numerical results is in good
agreement with the analytic solution and the present scheme offer
better accuracy in comparison with other existing numerical schemes.
Abstract: Data Grid is a geographically distributed environment that deals with data intensive application in scientific and enterprise computing. Data replication is a common method used to achieve efficient and fault-tolerant data access in Grids. In this paper, a dynamic data replication strategy, called Enhanced Latest Access Largest Weight (ELALW) is proposed. This strategy is an enhanced version of Latest Access Largest Weight strategy. However, replication should be used wisely because the storage capacity of each Grid site is limited. Thus, it is important to design an effective strategy for the replication replacement task. ELALW replaces replicas based on the number of requests in future, the size of the replica, and the number of copies of the file. It also improves access latency by selecting the best replica when various sites hold replicas. The proposed replica selection selects the best replica location from among the many replicas based on response time that can be determined by considering the data transfer time, the storage access latency, the replica requests that waiting in the storage queue and the distance between nodes. Simulation results utilizing the OptorSim show our replication strategy achieve better performance overall than other strategies in terms of job execution time, effective network usage and storage resource usage.
Abstract: Children today use computer based application in
various activities especially for learning and education. Many of
these tools and application such as the Computer Aided
Pronunciation Training (CAPT) systems enable children to explore
and experience them with little supervision from the adults. In order
for these tools and application to have maximum effect on the
children’s learning and education, it must be attractive to the children
to use them. This could be achieved with the proper user interface
(UI) design. As children grow, so do their ability, taste and
preferences. They interact differently with these applications as they
grow older. This study reviews several articles on how age factors
influence the UI design. The review focuses on age related abilities
such as cognitive, literacy, concentration and feedback requirement.
We have also evaluated few of existing CAPT systems and determine
the influence of age-based factors on the interface design.
Abstract: This paper presents a neural network based model predictive control (MPC) strategy to control a strongly exothermic reaction with complicated nonlinear kinetics given by Chylla-Haase polymerization reactor that requires a very precise temperature control to maintain product uniformity. In the benchmark scenario, the operation of the reactor must be guaranteed under various disturbing influences, e.g., changing ambient temperatures or impurity of the monomer. Such a process usually controlled by conventional cascade control, it provides a robust operation, but often lacks accuracy concerning the required strict temperature tolerances. The predictive control strategy based on the RBF neural model is applied to solve this problem to achieve set-point tracking of the reactor temperature against disturbances. The result shows that the RBF based model predictive control gives reliable result in the presence of some disturbances and keeps the reactor temperature within a tight tolerance range around the desired reaction temperature.
Abstract: This paper proposes a linear mixed model (LMM) with spatial effects to forecast rice and cassava yields in Thailand at the same time. A multivariate conditional autoregressive (MCAR) model is assumed to present the spatial effects. A Bayesian method is used for parameter estimation via Gibbs sampling Markov Chain Monte Carlo (MCMC). The model is applied to the rice and cassava yields monthly data which have been extracted from the Office of Agricultural Economics, Ministry of Agriculture and Cooperatives of Thailand. The results show that the proposed model has better performance in most provinces in both fitting part and validation part compared to the simple exponential smoothing and conditional auto regressive models (CAR) from our previous study.
Abstract: Prior literature on innovation diffusion or acceptance has almost exclusively concentrated on consumers’ positive attitudes and behaviors for new products/services. Consumers’ negative attitudes or behaviors to innovations have received relatively little marketing attention, but it happens frequently in practice. This study discusses consumer psychological factors when they try to learn or use new technologies. According to recent research, technological innovation acceptance has been considered as a dynamic or mediated process. This research argues that consumers can experience inertia and emotions in the initial use of new technologies. However, given such consumer psychology, the argument can be made as to whether the inclusion of consumer inertia (routine seeking and cognitive rigidity) and emotions increases the predictive power of new technology acceptance model. As data from the empirical study find, the process is potentially consumer emotion changing (independent of performance benefits) because of technology complexity and consumer inertia, and impact innovative technology use significantly. Finally, the study presents the superior predictability of the hypothesized model, which let managers can better predict and influence the successful diffusion of complex technological innovations.
Abstract: The analysis and design of thin shell structures is a topic of interest in a variety of engineering applications. In structural mechanics problems the analyst seeks to determine the distribution of stresses throughout the structure to be designed. It is also necessary to calculate the displacements of certain points of the structure to ensure that specified allowable values are not exceeded. In this paper a comparative study between displacement and strain based finite elements applied to the analysis of some thin shell structures is presented. The results obtained from some examples show the efficiency and the performance of the strain based approach compared to the well known displacement formulation.
Abstract: The sound pressure level (SPL) of the moving-coil
loudspeaker (MCL) is often simulated and analyzed using the lumped
parameter model. However, the SPL of a MCL cannot be simulated
precisely in the high frequency region, because the value of cone
effective area is changed due to the geometry variation in different
mode shapes, it is also related to affect the acoustic radiation mass and
resistance. Herein, the paper presents the inverse method which has a
high ability to measure the value of cone effective area in various
frequency points, also can estimate the MCL electroacoustic
parameters simultaneously. The proposed inverse method comprises
the direct problem, adjoint problem, and sensitivity problem in
collaboration with nonlinear conjugate gradient method. Estimated
values from the inverse method are validated experimentally which
compared with the measured SPL curve result. Results presented in
this paper not only improve the accuracy of lumped parameter model
but also provide the valuable information on loudspeaker cone design.
Abstract: This study presents the numerical simulation of three-dimensional incompressible steady and laminar fluid flow and conjugate heat transfer of a trapezoidal microchannel heat sink using water as a cooling fluid in a silicon substrate. Navier-Stokes equations with conjugate energy equation are discretized by finite-volume method. We perform numerical computations for a range of 50 ≦ Re ≦ 600, 0.05W ≦ P ≦ 0.8W, 20W/cm2 ≦q"≦ 40W/cm2. The present study demonstrates the numerical optimization of a trapezoidal microchannel heat sink design using the response surface methodology (RSM) and the genetic algorithm method (GA). The results show that the average Nusselt number increases with an increase in the Reynolds number or pumping power, and the thermal resistance decreases as the pumping power increases. The thermal resistance of a trapezoidal microchannel is minimized for a constant heat flux and constant pumping power.
Abstract: Sustainable urban waterfront development is one of the
most interesting phenomena of urban renewal in the last decades.
However, there are still many cities whose visual image is
compromised due to the lack of a sustainable urban waterfront
development, which consequently affects the place of those cities
globally. This paper aims to reimagine the role of waterfront areas in
city design, with a particular focus on Egypt, so that they provide
attractive, sustainable urban environments while promoting the
continued aesthetic development of the city overall. This aim will be
achieved by determining the main principles of a sustainable urban
waterfront and its applications. This paper concentrates on
sustainability assessment rating systems. A number of international
case-studies, wherein a city has applied the basic principles for a
sustainable urban waterfront and have made use of sustainability
assessment rating systems, have been selected as examples which can
be applied to the urban waterfronts in Egypt. This paper establishes the
importance of developing the design of urban environments in Egypt,
as well as identifying the methods of sustainability application for
urban waterfronts.
Abstract: As a developing country, The Kingdom of Saudi Arabia (KSA) needs to make the best possible use of its workforce for social and economic reasons. The workforce is diverse, calling for appropriate diversity management (DM). The thesis focuses on the banking sector in KSA. To date, there have been no studies on DM in the banking sector in this country. Many organizations have introduced specific policies and programmes to improve the recruitment, inclusion, promotion, and retention of diverse employees, in addition to the legal requirements existing in many countries. However, Western-centric models of DM may not be applicable, at least not in their entirety, in other regions.
The aim of the study is to devise a framework for understanding gender, age and disability DM in the banking sector in KSA in order to enhance DM in this sector. A sample of 24 managers, 2 from each of the 12 banks, was interviewed to obtain their views on DM in the banking sector in KSA. Thematic analysis was used to analyze the data. These themes were used to develop the questionnaire, which was administered to 10 managers in each of the 12 banks. After analysis of these data, and completion of the study, the research will make a theoretical contribution to the knowledge on DM and a practical contribution to the management of diversity in Saudi banks. This paper concerns a work in progress.
Abstract: In this study, Electrical Discharge Machining (EDM) is used to modify the surface of high carbon steel En31 with the help of tool electrode (Copper-Chromium-Nickel) manufactured by powder metallurgy (PM) process. The effect of EDM on surface roughness during surface alloying is studied. Taguchi’s Design of experiment (DOE) and L18 orthogonal array is used to find the best level of input parameters in order to achieve high surface finish. Six input parameters are considered and their percentage contribution towards surface roughness is investigated by analysis of variances (ANOVA). Experimental results show that an hard alloyed surface (1.21% carbon, 2.14% chromium and 1.38% nickel) with surface roughness of 3.19µm can be generated using EDM with PM tool. Additionally, techniques like Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS) are used to analyze the machined surface and EDMed layer composition, respectively. The increase in machined surface micro-hardness (101%) may be related to the formation of carbides containing chromium.
Abstract: In this paper, fractional order feedback control of a ball
beam model is investigated. The ball beam model is a particular
example of the double Integrator system having strongly nonlinear
characteristics and unstable dynamics which make the control of
such system a challenging task. Most of the work in fractional order
control systems are in theoretical nature and controller design and its
implementation in practice is very small. In this work, a successful
attempt has been made to design a fractional order PIλDμcontroller
for a benchmark laboratory ball and beam model. Better performance
can be achieved using a fractional order PID controller and it is
demonstrated through simulations results with a comparison to the
classic PID controller.
Abstract: Combustion phenomenon will be accomplished
effectively by the development of low emission combustor. One of the
significant factors influencing the entire Combustion process is the
mixing between a swirling angular jet (Primary Air) and the
non-swirling inner jet (fuel). To study this fundamental flow, the
chamber had to be designed in such a manner that the combustion
process to sustain itself in a continuous manner and the temperature of
the products is sufficiently below the maximum working temperature
in the turbine. This study is used to develop the effective combustion
with low unburned combustion products by adopting the concept of
high swirl flow and motility of holes in the secondary chamber. The
proper selection of a swirler is needed to reduce emission which can be
concluded from the emission of Nox and CO2. The capture of CO2 is
necessary to mitigate CO2 emissions from natural gas. Thus the
suppression of unburned gases is a meaningful objective for the
development of high performance combustor without affecting turbine
blade temperature.
Abstract: In this paper, the design of a coaxial feed single layer rectangular microstrip patch antenna for three different wireless communication band applications is presented. The proposed antenna is designed by using substrate Roger RT/duroid 5880 having permittivity of about 2.2 and tangent loss of 0.0009. The characteristics of the substrate are designed and to evaluate the performance of modeled antenna using HFSS v.11 EM simulator, from Ansoft. The proposed antenna has small in size and operates at 2.25GHz, 3.76GHz and 5.23GHz suitable for mobile satellite service (MSS) network, WiMAX and WLAN applications. The dimension of the patch and slots are optimized to obtain these desired functional frequency ranges. The simulation results with frequency response, radiation pattern and return loss, VSWR, Input Impedance are presented with appropriate table and graph.
Abstract: This research aims to critical analyze the feminine violent within Thai daily newspaper. This study was qualitative base; content analysis from two popular newspapers (Thairath and Dailynews) two qualitative newspapers (Thaipost and Mathichon). Purposive sampling was used to select eleven specialize news reporters to do in-depth interview. The result found that, popular newspapers, Thairath and dailynews have presented feminine violent news in their paper more than Thaipost and Mathichon the qualitative newspaper. Beside, majority of sample present the feminine violent within news under the code of ethic, The National Press Council of Thailand. Interesting, the age of feminine violent victim was the information that has been focused most. The popular newspaper have illustrated crime scene photo on their first-page while qualitative newspaper used only headline to present the same news.
Abstract: Castor (Ricinus communis L.) is one of the important
non-edible oilseed crops having immense industrial and medicinal
value. Oil yield per unit area is the ultimate target in growing oilseed
plants and sowing date is one of the important factors which have a
clear role on production of active substances particularly in oilseeds.
This study was conducted to evaluate the effect of sowing date on the
seed and oil yield of castor in Central Anatolia of Turkey in 2011.
The field experiment was set up in a completely randomized block
design with three replications. Black Diamond-2 castor cultivar was
used as plant material. The treatment was four sowing dates of May
10, May 25, June 10, June 25. In this research; seed yield, oil content
and oil yield were investigated. Results showed that the effect of
different sowing dates were significant on all of characteristics. In
general; delayed sowing dates, resulted in decreased seed yield, oil
content and oil yield. The highest value of seed yield, oil content and
oil yield (respectively, 2523.7 kg ha-1, 51.18% and 1292.2 kg ha-1)
were obtained from the first sowing date (May 10) while the lowest
seed yield, oil content and oil yield (respectively, 1550 kg ha-1,
43.67%, 677.3 kg ha-1) were recorded from the latest sowing date
(June 25). Therefore, it can be concluded that early May could be
recommended as an appropriate sowing date in the studied location
and similar climates for achieved high oil yield of castor.
Abstract: In order to respond the human needs, all regional, social, and economical factors are available to gain residents’ comfort and ideal architecture. There is no doubt the thermal comfort has to satisfy people not only for daily and physical activities but also creating pleasant area for mental activities and relaxing. It costs energy and increases greenhouse gas emissions.
Reducing energy use in buildings is a critical component of meeting carbon reduction commitments. Hence housing design represents a major opportunity to cut energy use and CO2 emissions.
In terms of energy efficiency, it is vital to propose and research modern design methods for buildings however vernacular architecture techniques are proven empirical existing practices which have to be considered. This research tries to compare two architectural solution were proposed by Persian vernacular architecture, to achieve energy efficiency in hot areas.
The aim of this research is to analyze two forms of traditional Persian architecture in different locations in order to develop a systematic research and sustainable technologies on adaptation to contemporary living standards.