Abstract: Bionanotechnology deals with nanoscopic interactions between nanostructured materials and biological systems. Polymer nanocomposites with optimized biological activity have attracted great attention. Nanoclay is considered as reinforcing nanofiller in manufacturing of high performance nanocomposites. In current study, organomodified-nanoclay with negatively charged silicate layers was incorporated into biomedical grade silicone rubber. Nanoparticle loading has been tailored to enhance cell behavior. Addition of nanoparticles led to improved mechanical properties of substrate with enhanced strength and stiffness while no toxic effects was observed. Results indicated improved viability and proliferation of cells by addition of nanofillers. The improved mechanical properties of the matrix result in proper cell response through adjustment and arrangement of cytoskeletal fibers. Results can be applied in tissue engineering when enhanced substrates are required for improvement of cell behavior for in vivo applications.
Abstract: The hydrodynamic processes in bubbly liquid flowing
in tubes and nozzles are studied theoretically and numerically. The
principal regularities of non-stationary processes of boiling liquid
outflow are established under conditions of experiments when the
depressurization of a tube with high pressure inside occurs. The
steady-state solution of bubbly liquid flow in the nozzle of round
cross section with high pressure and temperature conditions inside
bubbles is studied accounting for phase transition and chemical
reactions.
Abstract: Nigella sativa L. is an aromatic plant belonging to the
family Ranunculaceae. It has been used traditionally, especially in the
middle East and India, for the treatment of asthma, cough, bronchitis,
headache, rheumatism, fever, influenza and eczema. Several
biological activities have been reported in Nigella sativa seeds,
including antioxidant. In this context we tried to estimate the
antioxidant activity of various extracts prepared from Nigella sativa
seeds, methanolic extract (ME), chloroformic extract (CE), hexanic
extract (HE : fixed oil), ethyl acetate extract (EAE) water extract
(WE). The Folin-Ciocalteu assay showed that CE and EAE contained
high level of phenolic compounds 81.31 and 72.43μg GAE/mg of
extract respectively. Similarly, the CE and EAE exhibited the highest
DPPH radical scavenging activity, with IC50 values of 106.56μg/ml
and 121.62μg/ml respectively. In addition, CE and HE showed the
most scavenging activity against superoxide radical generated in the
PMS-NADH-NBT system with respective IC50 values of 361.86
μg/ml and 371.80 μg/ml, which is comparable to the activity of the
standard antioxidant BHT (344.59 μg/ml). Ferrous ion chelating
capacity assay showed that WE, EAE and ME are the most active
with 40.57, 39.70 and 22.02 mg EDTA-E/g of extract. The inhibition
of linoleic acid/ß-carotene coupled oxidation was estimated by ßcarotene
bleaching assay, this showed a highest relative antioxidant
activity with CE and EAE (69.82% of inhibition). The antioxidant
activities of the methanolic extract and the fixed oil are confirmed by
an in vivo assay in mice, the daily oral administration of methanolic
extract (500 and 800 mg/kg/day) and fixed oil (2 and 4 ml/kg/day)
during 21 days, resulted in a significant enhancement of the blood
total antioxidant capacity (measured by KRL test) and the plasmatic
antioxidant capacity towards DPPH radical.
Abstract: In this paper we developed the Improved Runge-Kutta Nystrom (IRKN) method for solving second order ordinary differential equations. The methods are two step in nature and require lower number of function evaluations per step compared with the existing Runge-Kutta Nystrom (RKN) methods. Therefore, the methods are computationally more efficient at achieving the higher order of local accuracy. Algebraic order conditions of the method are obtained and the third and fourth order method are derived with two and three stages respectively. The numerical results are given to illustrate the efficiency of the proposed method compared to the existing RKN methods.
Abstract: Databases have become ubiquitous. Almost all IT applications are storing into and retrieving information from databases. Retrieving information from the database requires knowledge of technical languages such as Structured Query Language (SQL). However majority of the users who interact with the databases do not have a technical background and are intimidated by the idea of using languages such as SQL. This has led to the development of a few Natural Language Database Interfaces (NLDBIs). A NLDBI allows the user to query the database in a natural language. This paper highlights on architecture of new NLDBI system, its implementation and discusses on results obtained. In most of the typical NLDBI systems the natural language statement is converted into an internal representation based on the syntactic and semantic knowledge of the natural language. This representation is then converted into queries using a representation converter. A natural language query is translated to an equivalent SQL query after processing through various stages. The work has been experimented on primitive database queries with certain constraints.
Abstract: The interdependences among stock market indices
were studied for a long while by academics in the entire world. The
current financial crisis opened the door to a wide range of opinions
concerning the understanding and measurement of the connections
considered to provide the controversial phenomenon of market
integration. Using data on the log-returns of 17 stock market indices
that include most of the CEE markets, from 2005 until 2009, our
paper studies the problem of these dependences using a new
methodological tool that takes into account both the volatility
clustering effect and the stochastic properties of these linkages
through a Dynamic Conditional System of Simultaneous Equations.
We find that the crisis is well captured by our model as it provides
evidence for the high volatility – high dependence effect.
Abstract: Nuts are part of a healthy diet such as Mediterranean diet. Benefits of nuts in reducing the risk of heart disease has been reasonably attributed to their composition of vitamins, minerals, unsaturated fatty acids, fiber and phytochemicals such as polyphenols, tocopherols, squalene and phytosterols. More than 75% of total fatty acids of nuts are unsaturated. α- tocopherol is the main tocopherol isomer present in most of the nuts. While walnuts, Brazil nut, cashew nut, peanut, pecan and pistachio nuts are rich in γ- tocopherol. β- sitosterol is dominant sterol in nuts. Pistachio and pine nut have the highest total phytosterol and Brazil nut and English walnut the lowest. Walnuts also contain large amount of phenolic compounds compared with other nuts. Nuts are rich in compounds with antioxidant properties and their consumption can offer preventing from incidence of many diseases including cardiovascular.
Abstract: Simulation and modeling computer programs are
concerned with construction of models for analyzing different
perspectives and possibilities in changing conditions environment.
The paper presents theoretical justification and evaluation of
qualitative e-learning development model in perspective of advancing
modern technologies. There have been analyzed principles of
qualitative e-learning in higher education, productivity of studying
process using modern technologies, different kind of methods and
future perspectives of e-learning in formal education. Theoretically
grounded and practically tested model of developing e-learning
methods using different technologies for different type of classroom,
which can be used in professor-s decision making process to choose
the most effective e-learning methods has been worked out.
Abstract: In pressure vessels contain hydrogen, the role of
hydrogen will be important because of hydrogen cracking problem. It
is difficult to predict what is happened in metallurgical field spite of a
lot of studies have been searched. The main role in controlling the
mass diffusion as driving force is related to stress. In this study, finite
element analysis is implemented to estimate material-s behavior
associated with hydrogen embrittlement. For this purpose, one model
of a pressure vessel is introduced that it has definite boundary and
initial conditions. In fact, finite element is employed to solve the
sequentially coupled mass diffusion with stress near a crack front in a
pressure vessel. Modeling simulation intergrarnular fracture of AISI
4135 steel due to hydrogen is investigated. So, distribution of
hydrogen and stress are obtained and they indicate that their
maximum amounts occur near the crack front. This phenomenon is
happened exactly the region between elastic and plastic field.
Therefore, hydrogen is highly mobile and can diffuse through crystal
lattice so that this zone is potential to trap high volume of hydrogen.
Consequently, crack growth and fast fracture will be happened.
Abstract: The objective of this study was to evaluate the
distribution patterns of Cd, Zn and Hg in groundwater by geospatial
interpolation. The study was performed at Rayong province in the
eastern part of Thailand, with high agricultural and industrial
activities. Groundwater samples were collected twice a year from 31
tubewells around this area. Inductively Coupled Plasma-Atomic
Emission Spectrometer (ICP-AES) was used to measure the
concentrations of Cd, Zn, and Hg in groundwater samples. The
results demonstrated that concentrations of Cd, Zn and Hg range
from 0.000-0.297 mg/L (x = 0.021±0.033 mg/L), 0.022-33.236 mg/L
(x = 4.214±4.766 mg/L) and 0.000-0.289 mg/L (x = 0.023±0.034
mg/L), respectively. Most of the heavy metals concentrations were
exceeded groundwater quality standards as specified in the Ministry
of Natural Resources and Environment, Thailand. The trend
distribution of heavy metals were high concentrations at the
southeastern part of the area that especially vulnerable to heavy
metals and other contaminants.
Abstract: The effects of upflow liquid velocity (ULV) on
performance of expanded granular sludge bed (EGSB) system were
investigated. The EGSB reactor, made from galvanized steel pipe
0.10 m diameter and 5 m height, had been used to treat piggery
wastewater, after passing through acidification tank. It consisted of
39.3 l working volume in reaction zone and 122 l working volume in
sedimentation zone, at the upper part. The reactor was seeded with
anaerobically digested sludge and operated at the ULVs of 4, 8, 12
and 16 m/h, consecutively, corresponding to organic loading rates of
9.6 – 13.0 kg COD/ (m3.d). The average COD concentrations in the
influent were 9,601 – 13,050 mg/l. The COD removal was not
significantly different, i.e. 93.0% - 94.0%, except at ULV 12 m/h where
SS in the influent was exceptionally high so that VSS washout had
occurred, leading to low COD removal. The FCOD and VFA
concentrations in the effluent of all experiments were not much
different, indicating the same range of treatment performance. The
biogas production decreased at higher ULV and ULV of 4 m/h is
suggested as design criterion for EGSB system.
Abstract: The use of technology is increasingly adopted to
support flexible learning in Higher Education institutions. The
adoption of more sophisticated technologies offers a broad range of
facilities for communication and resource sharing, thereby creating a
flexible learning environment that facilitates and even encourages
students not to physically attend classes. However this emerging
trend seems to contradict class attendance requirements within
universities, inevitably leading to a dilemma between amending
traditional regulations and creating new policies for the higher
education institutions. This study presents an investigation into
student engagement in a technology enhanced/driven flexible
environment along with its relationship to attainment. We propose an
approach to modelling engagement from different perspectives in
terms of indicators and then consider what impact these indicators
have on student academic performance. We have carried out a case
study on the relation between attendance and attainment in a flexible
environment. Although our preliminary results show attendance is
quantitatively correlated with successful student development and
learning outcomes, our results also indicate there is a cohort that did
not follow such a pattern. Nevertheless the preliminary results could
provide an insight into pilot studies in the wider deployment of new
technology to support flexible learning.
Abstract: In this paper, a new alignment method based on the particle swarm optimization (PSO) technique is presented. The PSO algorithm is used for locating the optimal coupling position with the highest optical power with three-degrees of freedom alignment. This algorithm gives an interesting results without a need to go thru the complex mathematical modeling of the alignment system. The proposed algorithm is validated considering practical tests considering the alignment of two Single Mode Fibers (SMF) and the alignment of SMF and PCF fibers.
Abstract: The purpose of this study is to identify the underlying
causes of late payment from the contractors- perspective in the
Malaysian construction industry and to recommend effective solutions
to mitigate late payment problems. The target groups of respondents in
this study were Grades G3, G5, G6 and G7 contractors with
specialization in building works and civil engineering works registered
with the Construction Industry Development Board (CIDB) in
Malaysia. Results from this study were analyzed with Statistical
Package for the Social Science (SPSS 15.0). From this study, it was
found that respondents have highest ranked five significant variables
out of a total of forty-one variables which can caused late payment
problems: a) cash flow problems due to deficiencies in client-s
management capacity (mean = 3.96); b) client-s ineffective utilization
of funds (mean = 3.88); c) scarcity of capital to finance the project
(mean = 3.81); d) clients failure to generate income from bank when
sales of houses do not hit the targeted amount (mean=3.72); and e)
poor cash flow because of lack of proper process implementation,
delay in releasing of the retention monies to contractor and delay in the
evaluation and certification of interim and final payment (mean =
3.66).
Abstract: The aim of the article is extending and developing
econometrics and network structure based methods which are able to
distinguish price manipulation in Tehran stock exchange. The
principal goal of the present study is to offer model for
approximating price manipulation in Tehran stock exchange. In order
to do so by applying separation method a sample consisting of 397
companies accepted at Tehran stock exchange were selected and
information related to their price and volume of trades during years
2001 until 2009 were collected and then through performing runs
test, skewness test and duration correlative test the selected
companies were divided into 2 sets of manipulated and non
manipulated companies. In the next stage by investigating
cumulative return process and volume of trades in manipulated
companies, the date of starting price manipulation was specified and
in this way the logit model, artificial neural network, multiple
discriminant analysis and by using information related to size of
company, clarity of information, ratio of P/E and liquidity of stock
one year prior price manipulation; a model for forecasting price
manipulation of stocks of companies present in Tehran stock
exchange were designed. At the end the power of forecasting models
were studied by using data of test set. Whereas the power of
forecasting logit model for test set was 92.1%, for artificial neural
network was 94.1% and multi audit analysis model was 90.2%;
therefore all of the 3 aforesaid models has high power to forecast
price manipulation and there is no considerable difference among
forecasting power of these 3 models.
Abstract: The use of Virtual Reality (VR) in schools and higher education is proliferating. Due to its interactive and animated features, it is regarded as a promising technology to increase students- spatial ability. Spatial ability is assumed to have a prominent role in science and engineering domains. However, research concerning individual differences such as spatial ability in the context of VR is still at its infancy. Moreover, empirical studies that focus on the features of VR to improve spatial ability are to date rare. Thus, this paper explores the possible educational values of VR in relation to spatial ability to call for more research concerning spatial ability in the context of VR based on studies in computerbased learning. It is believed that the incorporation of state-of-the-art VR technology for educational purposes should be justified by the enhanced benefits for the target learners.
Abstract: The pyrolysis characteristics and kinetics of seven marine biomass, which are fixed Enteromorpha clathrata, floating Enteromorpha clathrata, Ulva lactuca L., Zosterae Marinae L., Thallus Laminariae, Asparagus schoberioides kunth and Undaria pinnatifida (Harv.), were studied with thermogravimetric analysis method. Simultaneously, cornstalk, which is a grass biomass, and sawdust, which is a lignocellulosic biomass, were references. The basic pyrolysis characteristics were studied by using TG- DTG-DTA curves. The results showed that there were three stages (dehydration, dramatic weight loss and slow weight loss) during the whole pyrolysis process of samples. The Tmax of marine biomass was significantly lower than two kinds of terrestrial biomass. Zosterae Marinae L. had a relatively high stability of pyrolysis, but floating Enteromorpha clathrata had lowest stability of pyrolysis and a good combustion characteristics. The corresponding activation energy E and frequency factor A were obtained by Coats-Redfern method. It was found that the pyrolysis reaction mechanism functions of three kinds of biomass are different.
Abstract: The bridge vibration due to traffic loading has been a
subject of extensive research during the last decades. A number of
these studies are concerned with the effects of the unevenness of
roadways on the dynamic responses of highway bridges. The road
unevenness is often described as a random process that constitutes
of different wavelengths. Thus, the study focuses on examining
the effects of the random description of roadways on the dynamic
response and its variance. A new setting of variance based sensitivity
analysis is proposed and used to identify and quantify the
contributions of the roadway-s wavelengths to the variance of the
dynamic response. Furthermore, the effect of the vehicle-s speed on
the dynamic response is studied.
Abstract: A new and highly efficient architecture for elliptic curve scalar point multiplication which is optimized for a binary field recommended by NIST and is well-suited for elliptic curve cryptographic (ECC) applications is presented. To achieve the maximum architectural and timing improvements we have reorganized and reordered the critical path of the Lopez-Dahab scalar point multiplication architecture such that logic structures are implemented in parallel and operations in the critical path are diverted to noncritical paths. With G=41, the proposed design is capable of performing a field multiplication over the extension field with degree 163 in 11.92 s with the maximum achievable frequency of 251 MHz on Xilinx Virtex-4 (XC4VLX200) while 22% of the chip area is occupied, where G is the digit size of the underlying digit-serial finite field multiplier.
Abstract: In this study, we introduced a communication system
where human body was used as medium through which data were
transferred. Multiple biosignal sensing units were attached to a subject
and wireless personal area network was formed. Data of the sensing
units were shared among them. We used wideband pulse
communication that was simple, low-power consuming and high data
rated. Each unit functioned as independent communication device or
node. A method of channel search and communication among the
modes was developed. A protocol of carrier sense multiple
access/collision detect was implemented in order to avoid data
collision or interferences. Biosignal sensing units should be located at
different locations due to the nature of biosignal origin. Our research
provided a flexibility of collecting data without using electrical wires.
More non-constrained measurement was accomplished which was
more suitable for u-Health monitoring.