Abstract: Higher order ΔΣ Modulator (DSM) is basically an
unstable system. The approximate conditions for stability cannot be
used for the design of a DSM for industrial applications where risk is
involved. The existing second order, single stage, single bit, unity
feedback gain , discrete DSM cannot be used for the normalized full
range (-1 to +1) of an input signal since the DSM becomes unstable
when the input signal is above ±0.55. The stability is also not
guaranteed for input signals of amplitude less than ±0.55. In the
present paper, the above mentioned second order DSM is modified
with input signal dependent forward path gain. The proposed DSM is
suitable for industrial applications where one needs the digital
representation of the analog input signal, during each sampling
period. The proposed DSM can operate almost for the full range of
input signals (-0.95 to +0.95) without causing instability, assuming
that the second integrator output should not exceed the circuit supply
voltage, ±15 Volts.
Abstract: Alkylated silicon nanocrystals (C11-SiNCs) were
prepared successfully by galvanostatic etching of p-Si(100) wafers
followed by a thermal hydrosilation reaction of 1-undecene in
refluxing toluene in order to extract C11-SiNCs from porous silicon.
Erbium trichloride was added to alkylated SiNCs using a simple
mixing chemical route. To the best of our knowledge, this is the first
investigation on mixing SiNCs with erbium ions (III) by this
chemical method. The chemical characterization of C11-SiNCs and
their mixtures with Er3+(Er/C11-SiNCs) were carried out using X-ray
photoemission spectroscopy (XPS). The optical properties of C11-
SiNCs and their mixtures with Er3+ were investigated using Raman
spectroscopy and photoluminescence (PL). The erbium mixed
alkylated SiNCs shows an orange PL emission peak at around 595
nm that originates from radiative recombination of Si. Er/C11-SiNCs
mixture also exhibits a weak PL emission peak at 1536 nm that
originates from the intra-4f transition in erbium ions (Er3+). The PL
peak of Si in Er/C11-SiNCs mixture is increased in the intensity up to
three times as compared to pure C11-SiNCs. The collected data
suggest that this chemical mixing route leads instead to a transfer of
energy from erbium ions to alkylated SiNCs.
Abstract: Nowadays, the successful implementation of ICTs is
vital for almost any kind of organization. Good governance and ICT
management are essential for delivering value, managing
technological risks, managing resources and performance
measurement. In addition, outsourcing is a strategic IT service
solution which complements IT services provided internally in
organizations. This paper proposes the measurement tools of a new
holistic maturity model based on standards ISO/IEC 20000 and
ISO/IEC 38500, and the frameworks and best practices of ITIL and
COBIT, with a specific focus on IT outsourcing. These measurement
tools allow independent validation and practical application in the
field of higher education, using a questionnaire, metrics tables, and
continuous improvement plan tables as part of the measurement
process. Guidelines and standards are proposed in the model for
facilitating adaptation to universities and achieving excellence in the
outsourcing of IT services.
Abstract: Since large part of electricity is generated by using
fossil based resources, energy is an important agenda for countries. In
this context, renewable energy sources are alternative to conventional
sources due to the depletion of fossil resources, increasing awareness
of climate change and global warming concerns. Solar, wind and
hydropower energy are the main renewable energy sources. Among
of them, since installed capacity of wind power has increased
approximately eight times between 2008 - November of 2014, wind
energy is a promising source for Turkey. Furthermore, signing of
Kyoto Protocol can be accepted as a milestone for Turkey's energy
policy. Turkish Government has announced Vision 2023 (energy
targets by 2023) in 2010-2014 Strategic Plan prepared by Ministry of
Energy and Natural Resources (MENR). Energy targets in this plan
can be summarized as follows: Share of renewable energy sources in
electricity generation is 30% of total electricity generation by 2023.
Installed capacity of wind energy will be 20 GW by 2023. Other
renewable energy sources such as solar, hydropower and geothermal
are encouraged with new incentive mechanisms. Dependence on
foreign energy is reduced for sustainability and energy security. On
the other hand, since Turkey is surrounded by three coastal areas,
wind energy potential is convenient for wind power application. As
of November of 2014, total installed capacity of wind power plants is
3.51 GW and a lot of wind power plants are under construction with
capacity 1.16 GW. Turkish government also encourages the locally
manufactured equipments. In this context, one of the projects funded
by private sector, universities and TUBİTAK names as MILRES is
an important project aimed to promote the use wind energy in
electricity generation. Within this project, wind turbine with 500 kW
power has been produced and will be installed at the beginning of the
2015. After that, by using the experience obtained from the first
phase of the project, a wind turbine with 2.5 MW power will be
manufactured in an industrial scale.
Abstract: This paper presents a new structure of microstrip band
pass filter (BPF) based on coupled stepped impedance resonators.
Each filter consists of two coupled stepped impedance resonators
connected to microstrip feed lines. The coupled junction is utilized to
connect the two BPFs to the antenna. This two band pass filters are
designed and simulated to operate for the digital communication
system (DCS) and Industrial Scientific and Medical (ISM) bands at
1.8 GHz and 2.45 GHz respectively. The proposed circuit presents
good performances with an insertion loss lower than 2.3 dB and
isolation between the two channels greater than 21 dB. The prototype
of the optimized diplexer have been investigated numerically by
using ADS Agilent and verified with CST microwave software.
Abstract: The recommended limit for cadmium concentration in
potable water is less than 0.005 mg/L. A continuous biosorption
process using indigenous red seaweed, Gracilaria corticata, was
performed to remove cadmium from the potable water. The process
was conducted under fixed conditions and the breakthrough curves
were achieved for three consecutive sorption-desorption cycles. A
modeling based on Artificial Neural Network (ANN) was employed
to fit the experimental breakthrough data. In addition, a simplified
semi empirical model, Thomas, was employed for this purpose. It
was found that ANN well described the experimental data (R2>0.99)
while the Thomas prediction were a bit less successful with R2>0.97.
The adjusted design parameters using the nonlinear form of Thomas
model was in a good agreement with the experimentally obtained
ones. The results approve the capability of ANN to predict the
cadmium concentration in potable water.
Abstract: The problematic of gender and socioeconomic status
biased differences in academic motivation patterns is discussed.
Gender identity is understood according to symbolic interactionism
perspective: as a result of reflected appraisals, social comparisons,
self-attributions, and identifications, shaped by social environment
and family context. The effects of socioeconomic status on academic
motivation are conceptualized according to Bourdieu’s habitus
concept, reflecting the role of unconscious and internalized cultural
signals, proper to low and high socioeconomic status family contexts.
Since families differ by various socioeconomic features, the
hypothesis about possible impact of parents’ socioeconomic status on
their children’s academic motivation interfering with gender
socialization effects is held. The survey, aiming to seize gender
differences in academic motivation and self-recorded improvementoriented
efforts as a result of socialization processes operating in the
families of low and high socioeconomic status, was designed. The
results of Lithuanian higher education students’ survey are presented
and discussed.
Abstract: In this paper a new design of a broadband microwave
power limiter is presented and validated into simulation by using
ADS software (Advanced Design System) from Agilent technologies.
The final circuit is built on microstrip lines by using identical Zero
Bias Schottky diodes. The power limiter is designed by Associating 3
stages Schottky diodes. The obtained simulation results permit to
validate this circuit with a threshold input power level of 0 dBm until
a maximum input power of 30 dBm.
Abstract: The ad hoc networks are the future of wireless
technology as everyone wants fast and accurate error free information
so keeping this in mind Bit Error Rate (BER) and power is optimized
in this research paper by using the Genetic Algorithm (GA). The
digital modulation techniques used for this paper are Binary Phase
Shift Keying (BPSK), M-ary Phase Shift Keying (M-ary PSK), and
Quadrature Amplitude Modulation (QAM). This work is
implemented on Wireless Ad Hoc Networks (WLAN). Then it is
analyze which modulation technique is performing well to optimize
the BER and power of WLAN.
Abstract: In this study, we are interested in a species of the
family of Asteraceae (Tagetes erecta). This family is considered as a
source of antimicrobial extracts with strong capacity. The extraction
of the flavonoids is carried out by the method of liquid/liquid with the
use of successive solvents. Afterwards, we evaluated the biological
activity of the flavonoids on five pathogenic bacterial stocks such as
Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae,
Pseudomonas aeruginosa and Staphylococcus aureus and two stocks
of yeasts to knowing Candida albicans) and Saccharomyces
cerevisiae, by employing the method of the aromatogramme starting
from a solid disc. The result of the antimicrobial activity shows an
action and a variable degree of sensitivity according to bacterial
stocks tested. It will be noted that the flavonoids have an inhibiting
effect on E. coli, B. subtilis, K. pneumoniae and S. aureus. But a
resistance with respect to the extract by P. aeruginosa, C. albicans
and S. cerevisiae is to be mentioned.
Abstract: A field experiment was carried out at Arab El-
Awammer Research Station, Agric. Res. Center. Assiut Governorate
during summer seasons of 2013 and 2014. The present study assessed
the effect of cowpea with maize intercropping on yield and its
components. The experiment comprised of three treatments (sole
cowpea, sole maize and cowpea-maize intercrop). The experimental
design was a randomized complete block with four replications.
Results indicated that intercropped maize plants with cowpea,
exhibited greater potentiality and resulted in higher values of most of
the studied criteria viz., plant height, number of ears/plant, number of
rows/ear, number of grains/row, grains weight/ear, 100–grain weight
and straw and grain yields. Fresh and dry forage yields of cowpea
were lower in intercropping with maize than sole. Furthermore, the
combined of the two seasons revealed that the total Land Equivalent
Ratio (LER) between cowpea and maize was 1.65. The Aggressivity
(A) maize was 0.45 and cowpea was -0.45. This showed that maize
was the dominant crop, whereas cowpea was the dominated. The
Competitive Ratio (CR) indicated that maize more competitive than
cowpea, maize was 1.75 and cowpea was 0.57. The Actual Yield
Loss (AYL) maize was 0.05 and cowpea was -0.40. The Monetary
Advantage Index (MAI) was 2360.80.
Abstract: Steganography is the art and science that hides the information in an appropriate cover carrier like image, text, audio and video media. In this work the authors propose a new image based steganographic method for hiding information within the complex bit planes of the image. After slicing into bit planes the cover image is analyzed to extract the most complex planes in decreasing order based on their bit plane complexity. The complexity function next determines the complex noisy blocks of the chosen bit plane and finally pixel mapping method (PMM) has been used to embed secret bits into those regions of the bit plane. The novel approach of using pixel mapping method (PMM) in bit plane domain adaptively embeds data on most complex regions of image, provides high embedding capacity, better imperceptibility and resistance to steganalysis attack.
Abstract: This study presents an attempt to evaluate the
antioxidant potential and antimicrobial activity of methanolic extract,
and essential oils prepared from the leaves of sage (Salvia officinalis
L.). The content of polyphenol in the methanolic extracts from the
leaves of Salvia officinalis was determined spectrophotometrically,
calculated as gallic acid and catechin equivalent. The essential oils
and methanol extract were also subjected to screenings for the
evaluation of their antioxidant activities using 2, 2-diphenyl-1-
picrylhydrazyl (DPPH) test. While the plant essential oils showed
only weak antioxidant activities, its methanol extract was
considerably active in DPPH (IC50 = 37.29 μg/ml) test. Appreciable
total polyphenol content (31.25 mg/g) was also detected for the plant
methanol extract as gallic acid equivalent in the Folin–Ciocalteu test.
The plant was also screened for its antimicrobial activity and good to
moderate inhibitions were recorded for its essential oils, and
methanol extracts against most of the tested microorganisms.
The present investigation revealed that this plant had rich source
of antioxidant properties. It is for this reason that sage has found
increasing application in food formulations.
Abstract: In this paper, the dynamic characteristics of a threelobe
journal bearing lubricated with micropolar fluids are determined
by the linear stability theory. Lubricating oil containing additives and
contaminants is modelled as micropolar fluid. The modified
Reynolds equation is obtained using the micropolar lubrication theory
.The finite difference technique has been used to determine the
solution of the modified Reynolds equation. The dynamic
characteristics in terms of stiffness, damping coefficients, the critical
mass and whirl ratio are determined for various values of size of
material characteristic length and the coupling number. The
computed results show that the three-lobe bearing lubricated with
micropolar fluid exhibits better stability compared with that
lubricated with Newtonian fluid. According to the results obtained,
the effect of the parameter micropolar fluid is remarkable on the
dynamic characteristics and stability of the three-lobe bearing.
Abstract: Carbon nanotube is one of the most attractive materials
for the potential applications of nanotechnology due to its excellent
mechanical, thermal, electrical and optical properties. In this paper we
report a supercapacitor made of nickel foil electrodes, coated with
multiwall carbon nanotubes (MWCNTs) thin film using
electrophoretic deposition (EPD) method. Chemical vapor deposition
method was used for the growth of MWCNTs and ethanol was used as
a hydrocarbon source. High graphitic multiwall carbon nanotube was
found at 750oC analyzing by Raman spectroscopy. We observed the
electrochemical performance of supercapacitor by cyclic
voltammetry. The electrodes of supercapacitor fabricated from
MWCNTs exhibit considerably small equivalent series resistance
(ESR), and a high specific power density. Electrophoretic deposition
is an easy method in fabricating MWCNT electrodes for high
performance supercapacitor.
Abstract: This paper investigates the joint effect of the
interconnected (n,k)-star network topology and Multi-Agent
automated control on restoration and reconfiguration of power
systems. With the increasing trend in development in Multi-Agent
control technologies applied to power system reconfiguration
in presence of faulty components or nodes. Fault tolerance is
becoming an important challenge in the design processes of the
distributed power system topology. Since the reconfiguration of a
power system is performed by agent communication, the (n,k)-star
interconnected network topology is studied and modeled in this
paper to optimize the process of power reconfiguration. In this paper,
we discuss the recently proposed (n,k)-star topology and examine its
properties and advantages as compared to the traditional multi-bus
power topologies. We design and simulate the topology model for
distributed power system test cases. A related lemma based on the
fault tolerance and conditional diagnosability properties is presented
and proved both theoretically and practically. The conclusion is
reached that (n,k)-star topology model has measurable advantages
compared to standard bus power systems while exhibiting fault
tolerance properties in power restoration, as well as showing
efficiency when applied to power system route discovery.
Abstract: In wireless communication, space-time block code (STBC), cyclic delay diversity (CDD) and space-time cyclic delay diversity (STCDD)are used as the spatial diversity schemes and have been widely studied for the reliablecommunication. If these schemes are used, the communication system can obtain the improved performance. However,the quality of the system is degraded when the distance between a source and a destination is distant in wireless communication system. In this paper, the cooperative transmission scheme using two sources is proposed and improves the performance of the wireless communication system.
Abstract: Nanocrystalline powders of the lead-free piezoelectric
material, tantalum-substituted potassium sodium niobate
(K0.5Na0.5)(Nb0.9Ta0.1)O3 (KNNT), were produced using a Retsch
PM100 planetary ball mill by setting the milling time to 15h, 20h,
25h, 30h, 35h and 40h, at a fixed speed of 250rpm. The average
particle size of the milled powders was found to decrease from 12nm
to 3nm as the milling time increases from 15h to 25h, which is in
agreement with the existing theoretical model. An anomalous
increase to 98nm and then a drop to 3nm in the particle size were
observed as the milling time further increases to 30h and 40h
respectively. Various sizes of these starting KNNT powders were
used to investigate the effect of milling time on the microstructure,
dielectric properties, phase transitions and piezoelectric properties of
the resulting KNNT ceramics. The particle size of starting KNNT
was somewhat proportional to the grain size. As the milling time
increases from 15h to 25h, the resulting ceramics exhibit
enhancement in the values of relative density from 94.8% to 95.8%,
room temperature dielectric constant (εRT) from 878 to 1213, and
piezoelectric charge coefficient (d33) from 108pC/N to 128pC/N. For
this range of ceramic samples, grain size refinement suppresses the
maximum dielectric constant (εmax), shifts the Curie temperature (Tc)
to a lower temperature and the orthorhombic-tetragonal phase
transition (Tot) to a higher temperature. Further increase of milling
time from 25h to 40h produces a gradual degradation in the values of
relative density, εRT, and d33 of the resulting ceramics.
Abstract: Two types of glass fibers having different lengths
(1/16" and 1/32") were added into rigid PVC foams to enhance the
dimensional stability of extruded rigid Polyvinyl Chloride (PVC)
foam at different concentrations (0-20 phr) using a single screw
profile extruder. PVC foam-glass fiber composites (PVC-GF) were
characterized for their dimensional stability, structural, thermal, and
mechanical properties. Experimental results show that the
dimensional stability, heat resistance, and storage modulus were
enhanced without compromising the tensile and flexural strengths of
the composites. Overall, foam composites which were prepared with
longer glass fibers exhibit better mechanical and thermal properties
than those prepared with shorter glass fibers due to higher
interlocking between the fibers and the foam cells, which result in
better load distribution in the matrix.
Abstract: We model and simulate the combined effect of fiber
dispersion and frequency chirp of a directly modulated high-speed
laser diode on the figures of merit of a non-amplified 40-Gbps optical
fiber link. We consider both the return to zero (RZ) and non-return to
zero (NRZ) patterns of the pseudorandom modulation bits. The
performance of the fiber communication system is assessed by the
fiber-length limitation due to the fiber dispersion. We study the
influence of replacing standard single-mode fibers by non-zero
dispersion-shifted fibers on the maximum fiber length and evaluate
the associated power penalty. We introduce new dispersion
tolerances for 1-dB power penalty of the RZ and NRZ 40-Gbps
optical fiber links.