Abstract: In this article, we synthesize a novel chitosan -based
superabsorbent hydrogel via graft copolymerization of mixtures
acrylic acid (AA) and N-vinyl pyrollidon onto chitosan backbones.
The polymerization reaction was carried out in an aqueous medium
and in the presence of ammonium persulfate (APS) as an initiator and
N,N'-methylene bisacrylamide (MBA) as a crosslinker.The hydrogel
structures were confirmed by FTIR spectroscopy. The swelling
behavior of these absorbent polymers was also investigated in
various salt solutions. Results indicated that the swelling capacity
decreased with an increase in the ionic strength of the swelling
medium. Furthermore, the swelling of superabsorbing hydrogels was
examined in solutions with pH values ranging between 1.0 and 13.0.
It showed a reversible pH-responsive behavior at pHs 2.0 and 8.0.
This on-off switching behavior makes the synthesized hydrogels as
an excellent candidate for controlled delivery of bioactive agents.
Abstract: Entrepreneurship has become an important and
extensively researched concept in business studies. Research on
foreign direct investment (FDI) has become widespread due to the
growth of FDI and its importance in globalization. Most
entrepreneurship studies examined the importance and influence of
entrepreneurial orientation in a micro-level context. On the other
hand, studies and research concerning FDI used statistical techniques
to analyze the effect, determinants, and motives of FDI on a
macroeconomic level, ignoring empirical studies on other noneconomic
determinants. In order to bridge the gap between the theory
and empirical evidence on FDI and the theory and research on
entrepreneurship, this study examines the impact of entrepreneurship
on inward foreign direct investment. The relationship between
entrepreneurship and foreign direct investment is investigated
through regression analysis of pooled time-series and cross-sectional
data. The results suggest that entrepreneurship has a significant effect
on FDI.
Abstract: In this paper, the application of thermal spray
coatings in high speed shafts by a revolution up to 23000 RPM
has been studied. Gas compressor shafts are worn in contact
zone with journal therefore will be undersized. Wear
mechanisms of compressor shaft were identified. The
predominant wear mechanism is abrasion wear. The worn
surface was coated by hard WC-Co cermets using high
velocity oxy fuel (HVOF) after preparation. The shafts were in
satisfactory service in 8000h period. The metallurgical and
Tribological studies has been made on the worn and coated
shaft using optical microscopy, scanning electron microscopy
(SEM) and X-ray diffraction.
Abstract: In this paper, an automatic determination algorithm for nuclear magnetic resonance (NMR) spectra of the metabolites in the living body by magnetic resonance spectroscopy (MRS) without human intervention or complicated calculations is presented. In such method, the problem of NMR spectrum determination is transformed into the determination of the parameters of a mathematical model of the NMR signal. To calculate these parameters efficiently, a new model called modified Hopfield neural network is designed. The main achievement of this paper over the work in literature [30] is that the speed of the modified Hopfield neural network is accelerated. This is done by applying cross correlation in the frequency domain between the input values and the input weights. The modified Hopfield neural network can accomplish complex dignals perfectly with out any additinal computation steps. This is a valuable advantage as NMR signals are complex-valued. In addition, a technique called “modified sequential extension of section (MSES)" that takes into account the damping rate of the NMR signal is developed to be faster than that presented in [30]. Simulation results show that the calculation precision of the spectrum improves when MSES is used along with the neural network. Furthermore, MSES is found to reduce the local minimum problem in Hopfield neural networks. Moreover, the performance of the proposed method is evaluated and there is no effect on the performance of calculations when using the modified Hopfield neural networks.
Abstract: Stable bacterial polymorphism on a single limiting resource may appear if between the evolved strains metabolic interactions take place that allow the exchange of essential nutrients [8]. Towards an attempt to predict the possible outcome of longrunning evolution experiments, a network based on the metabolic capabilities of homogeneous populations of every single gene knockout strain (nodes) of the bacterium E. coli is reconstructed. Potential metabolic interactions (edges) are allowed only between strains of different metabolic capabilities. Bacterial communities are determined by finding cliques in this network. Growth of the emerged hypothetical bacterial communities is simulated by extending the metabolic flux balance analysis model of Varma et al [2] to embody heterogeneous cell population growth in a mutual environment. Results from aerobic growth on 10 different carbon sources are presented. The upper bounds of the diversity that can emerge from single-cloned populations of E. coli such as the number of strains that appears to metabolically differ from most strains (highly connected nodes), the maximum clique size as well as the number of all the possible communities are determined. Certain single gene deletions are identified to consistently participate in our hypothetical bacterial communities under most environmental conditions implying a pattern of growth-condition- invariant strains with similar metabolic effects. Moreover, evaluation of all the hypothetical bacterial communities under growth on pyruvate reveals heterogeneous populations that can exhibit superior growth performance when compared to the performance of the homogeneous wild-type population.
Abstract: Pressure waves and Water Hammer occur in a
pumping system when valves are closed or opened suddenly or in
the case of sudden failure of pumps. Determination of maximum
water hammer is considered one of the most important technical
and economical items of which engineers and designers of
pumping stations and conveyance pipelines should take care.
Hammer Software is a recent application used to simulate water
hammer. The present study focuses on determining significance of
each input parameter of the application relative to the maximum
amount of water hammer estimated by the software. The study
determines estimated maximum water hammer variations due to
variations of input parameters including water temperature, pipe
type, thickness and diameter, electromotor rpm and power, and
moment of inertia of electromotor and pump. In our study,
Kuhrang Pumping Station was modeled using WaterGEMS
Software. The pumping station is characterized by total discharge
of 200 liters per second, dynamic height of 194 meters and 1.5
kilometers of steel conveyance pipeline and transports water to
Cheshme Morvarid for farmland irrigation. The model was run in
steady hydraulic condition and transferred to Hammer Software.
Then, the model was run in several unsteady hydraulic conditions
and sensitivity of maximum water hammer to each input parameter
was calculated. It is shown that parameters to which maximum
water hammer is most sensitive are moment of inertia of pump and
electromotor, diameter, type and thickness of pipe and water
temperature, respectively.
Abstract: In Croatia, the majority of cultured marine fish species are reared in net cages. The intensive production of the fish in net cages may generate the considerable amount of bio waste and change water quality especially in enclosed and semi-enclosed coastal areas. The aim of this paper is to assess the potential impact of sea bass (Dicentrarchus labrax L.) cage farm on water quality. The weak relationship between food supply and water quality parameters (nutrient content and phytoplankton biomass) was found, but significant changes in oxygen saturation was observed in the cages during the warmer period of a year especially in the morning (occasionally it dropped below 70 %). Despite of, satisfactory results of water quality parameters, it is necessary to establish comprehensive monitoring process, especially to include quality assessment of fouling communities.
Abstract: This paper describes the design concepts and
implementation of a 5-Joint mechanical arm for a rescue robot named
CEO Mission II. The multi-joint arm is a five degree of freedom
mechanical arm with a four bar linkage, which can be stretched to
125 cm. long. It is controlled by a teleoperator via the user-friendly
control and monitoring GUI program. With Inverse Kinematics
principle, we developed the method to control the servo angles of all
arm joints to get the desired tip position. By clicking the determined
tip position or dragging the tip of the mechanical arm on the
computer screen to the desired target point, the robot will compute
and move its multi-joint arm to the pose as seen on the GUI screen.
The angles of each joint are calculated and sent to all joint servos
simultaneously in order to move the mechanical arm to the desired
pose at once. The operator can also use a joystick to control the
movement of this mechanical arm and the locomotion of the robot.
Many sensors are installed at the tip of this mechanical arm for
surveillance from the high level and getting the vital signs of victims
easier and faster in the urban search and rescue tasks. It works very
effectively and easy to control. This mechanical arm and its software
were developed as a part of the CEO Mission II Rescue Robot that
won the First Runner Up award and the Best Technique award from
the Thailand Rescue Robot Championship 2006. It is a low cost,
simple, but functioning 5-Jiont mechanical arm which is built from
scratch, and controlled via wireless LAN 802.11b/g. This 5-Jiont
mechanical arm hardware concept and its software can also be used
as the basic mechatronics to many real applications.
Abstract: We discuss the signal detection through nonlinear
threshold systems. The detection performance is assessed by the
probability of error Per . We establish that: (1) when the signal is
complete suprathreshold, noise always degrades the signal detection
both in the single threshold system and in the parallel array of
threshold devices. (2) When the signal is a little subthreshold, noise
degrades signal detection in the single threshold system. But in the
parallel array, noise can improve signal detection, i.e., stochastic
resonance (SR) exists in the array. (3) When the signal is predominant
subthreshold, noise always can improve signal detection and SR
always exists not only in the single threshold system but also in the
parallel array. (4) Array can improve signal detection by raising the
number of threshold devices. These results extend further the
applicability of SR in signal detection.
Abstract: this paper presents a novel scheme which is capable of reducing the error rate and improves the transmission performance in the asynchronous cooperative MIMO systems. A case study of image transmission is applied to prove the efficient of scheme. The linear dispersion structure is employed to accommodate the cooperative wireless communication network in the dynamic topology of structure, as well as to achieve higher throughput than conventional space–time codes based on orthogonal designs. The LDPC encoder without girth-4 and the STBC encoder with guard intervals are respectively introduced. The experiment results show that the combined coder of LDPC-STBC with guard intervals can be the good error correcting coders and BER performance in the asynchronous cooperative communication. In the case study of image transmission, the results show that in the transmission process, the image quality which is obtained by applied combined scheme is much better than it which is not applied the scheme in the asynchronous cooperative MIMO systems.
Abstract: E-Learning systems are used by many learners and
teachers. The developer is developing the e-Learning system. However,
the developer cannot do system construction to satisfy all of
users- demands. We discuss a method of constructing e-Learning
systems where learners and teachers can design, try to use, and share
extending system functions that they want to use; which may be nally
added to the system by system managers.
Abstract: In this work we study the effect of several covariates X on a censored response variable T with unknown probability distribution. In this context, most of the studies in the literature can be located in two possible general classes of regression models: models that study the effect the covariates have on the hazard function; and models that study the effect the covariates have on the censored response variable. Proposals in this paper are in the second class of models and, more specifically, on least squares based model approach. Thus, using the bootstrap estimate of the bias, we try to improve the estimation of the regression parameters by reducing their bias, for small sample sizes. Simulation results presented in the paper show that, for reasonable sample sizes and censoring levels, the bias is always smaller for the new proposals.
Abstract: As a vital activity for companies, new product
development (NPD) is also a very risky process due to the high
uncertainty degree encountered at every development stage and the
inevitable dependence on how previous steps are successfully
accomplished. Hence, there is an apparent need to evaluate new
product initiatives systematically and make accurate decisions under
uncertainty. Another major concern is the time pressure to launch a
significant number of new products to preserve and increase the
competitive power of the company. In this work, we propose an
integrated decision-making framework based on neural networks and
fuzzy logic to make appropriate decisions and accelerate the
evaluation process. We are especially interested in the two initial
stages where new product ideas are selected (go/no go decision) and
the implementation order of the corresponding projects are
determined. We show that this two-staged intelligent approach allows
practitioners to roughly and quickly separate good and bad product
ideas by making use of previous experiences, and then, analyze a
more shortened list rigorously.
Abstract: Pyritisation halos are identified in weathering crusts and unconsolidated formations at five locations within large fault structure of the Urals’ eastern slope. Electron microscopy reveals the presence of inclusions and growths on pyrite faces – normally on cubic pyrite with striations, or combinations of cubes and other forms. Following neogenesis types are established: native elements and intermetallic compounds (including gold and silver), halogenides, sulphides, sulfosalts, tellurides, sulphotellurides,
selenides, tungstates, sulphates, phosphates, carbon-based substances. Direct relationship is noted between amount and diversity of such mineral phases, and proximity to and scale of ore-grade mineralization. Gold and silver, both in native form and within tellurides, presence of lead (galena, native lead), native tungsten, and, possibly, molybdenite and sulfosalts can indicate gold-bearing formations. First find of native tungsten in the Urals is for the first time – in crystallised and druse-like form. Link is suggested between unusual mineralization and “reducing” hydrothermal fluids from deep-seated faults at later stages of Urals’ reactivation.
Abstract: The significant effects of the interactions between the
system boundaries and the near wall molecules in miniaturized
gaseous devices lead to the formation of the Knudsen layer in which
the Navier-Stokes-Fourier (NSF) equations fail to predict the correct
associated phenomena. In this paper, the well-known lattice
Boltzmann method (LBM) is employed to simulate the fluid flow and
heat transfer processes in rarefied gaseous micro media. Persuaded
by the problematic deficiency of the LBM in capturing the Knudsen
layer phenomena, present study tends to concentrate on the effective
molecular mean free path concept the main essence of which is to
compensate the incapability of this mesoscopic method in dealing
with the momentum and energy transport within the above mentioned
kinetic boundary layer. The results show qualitative and quantitative
accuracy comparable to the solutions of the linearized Boltzmann
equation or the DSMC data for the Knudsen numbers of O (1) .
Abstract: Natural gas usually includes H2S component which is
very toxic, hazardous and corrosive to environment, human being and
process equipments, respectively. Therefore, sweetening of the gas
(separation of H2S) is inevitable. To achieve this purpose, using
packed-bed columns with liquid absorbents such as MEA or DEA is
very common. Due to some problems of usual packed columns
especially high pressure drop of gas phase, a novel kind of them
called wetted-wire column (WWC) has been invented. The column
decreases the pressure drop significantly and improves the absorption
efficiency. The packings are very thin rods (like wire) and as long as
column. The column has 100 wires with a triangular arrangement and
counter current flows of gas and liquid phases. The observation
showed that at the same conditions, the absorption performance was
quite comparable to conventional packed-bed towers and a very low
pressure drop.
Abstract: Designing and implementing intelligent systems has become a crucial factor for the innovation and development of better products of space technologies. A neural network is a parallel system, capable of resolving paradigms that linear computing cannot. Field programmable gate array (FPGA) is a digital device that owns reprogrammable properties and robust flexibility. For the neural network based instrument prototype in real time application, conventional specific VLSI neural chip design suffers the limitation in time and cost. With low precision artificial neural network design, FPGAs have higher speed and smaller size for real time application than the VLSI and DSP chips. So, many researchers have made great efforts on the realization of neural network (NN) using FPGA technique. In this paper, an introduction of ANN and FPGA technique are briefly shown. Also, Hardware Description Language (VHDL) code has been proposed to implement ANNs as well as to present simulation results with floating point arithmetic. Synthesis results for ANN controller are developed using Precision RTL. Proposed VHDL implementation creates a flexible, fast method and high degree of parallelism for implementing ANN. The implementation of multi-layer NN using lookup table LUT reduces the resource utilization for implementation and time for execution.
Abstract: The present study was conducted to observe the effect
of Plantago psyllium on blood glucose and cholesterol levels in
normal and alloxan induced diabetic rats. To investigate the effect of
Plantago psyllium 40 rats were included in this study divided into
four groups of ten rats in each group. One group A was normal,
second group B was diabetic, third group C was non diabetic and
hypercholesterolemic and fourth group D was diabetic and
hypercholesterolemic. Two groups B and D were made diabetic by
intraperitonial injection of alloxan dissolved in 1mL distilled water at
a dose of 125mg/Kg of body weight. Two groups C and D were
made hypercholesterolemic by oral administration of powder
cholesterol (1g/Kg of body weight). The blood samples from all the
rats were collected from coccygial vein on 1st day, then on 21st and
42nd day respectively. All the samples were analyzed for blood
glucose and cholesterol level by using enzymatic kits. The blood
glucose and cholesterol levels of treated groups of rats showed
significant reduction after 7 weeks of treatment with Plantago
psyllium. By statistical analysis of results it was found that Plantago
psyllium has anti-diabetic and hypocholesterolemic activity in
diabetic and hypercholesterolemic albino rats.
Abstract: This study investigated the relationship between urban
and rural ozone concentrations and quantified the extent to which
ambient rural conditions and the concentrations of other pollutants
can be used to predict urban ozone concentrations. The study
describes the variations of ozone in weekday and weekends as well as
the daily maximum recorded at selected monitoring stations. The
results showed that Putrajaya station had the highest concentrations
of O3 on weekend due the titration of NO during the weekday.
Additionally, Jerantut had the lowest average concentration with a
reading value high on Wednesdays. The comparisons of average and
maximum concentrations of ozone for the three stations showed that
the strongest significant correlation is recorded in Jerantut station
with the value R2= 0.769. Ozone concentrations originating from a
neighbouring urban site form a better predictor to the urban ozone
concentrations than widespread rural ozone at some levels of
temporal averaging. It is found that in urban and rural of Malaysian
peninsular, the concentration of ozone depends on the concentration
of NOx and seasonal meteorological factors. The HYSPLIT Model
(the northeast monsoon) showed that the wind direction can also
influence the concentration of ozone in the atmosphere in the studied
areas.
Abstract: In this work, we present a comparison between
different techniques of image compression. First, the image is
divided in blocks which are organized according to a certain scan.
Later, several compression techniques are applied, combined or
alone. Such techniques are: wavelets (Haar's basis), Karhunen-Loève
Transform, etc. Simulations show that the combined versions are the
best, with minor Mean Squared Error (MSE), and higher Peak Signal
to Noise Ratio (PSNR) and better image quality, even in the presence
of noise.