Abstract: This paper presents the study of a variable speed wind
energy conversion system based on a Doubly Fed Induction Generator
(DFIG) based on a sliding mode control applied to achieve control of
active and reactive powers exchanged between the stator of the DFIG
and the grid to ensure a Maximum Power Point Tracking (MPPT) of
a wind energy conversion system. The proposed control algorithm is
applied to a DFIG whose stator is directly connected to the grid and
the rotor is connected to the PWM converter. To extract a maximum
of power, the rotor side converter is controlled by using a stator
flux-oriented strategy. The created decoupling control between active
and reactive stator power allows keeping the power factor close to
unity. Simulation results show that the wind turbine can operate at
its optimum energy for a wide range of wind speed.
Abstract: Biochemical investigations were carried out to assess
the effect of different exposure regimes of Kazakhstan crude oil
(KCO) on hepatic antioxidant defense system in albino rats.
Contaminants were delivered under two different dosing regimes,
with all treatments receiving the same total contaminant load by the
end of the exposure period. Rats in regime A injected with KCO
once at a dose of 6 ml/kg bw while in regime B injected multiply at a
dose of 1.5 ml/kg bw on day 1, 3, 5 and 8. Antioxidant biomarkers
were measured in hepatic tissue after 1, 3, 5 and 8 days. Significant
induction was observed in serum aminotransferases (ALT, AST)
(p
Abstract: The impact of fixed speed squirrel cage type as well as
variable speed doubly fed induction generators (DFIG) on dynamic
performance of a multimachine power system has been investigated.
Detailed models of the various components have been presented and
the integration of asynchronous and synchronous generators has been
carried out through a rotor angle based transform. Simulation studies
carried out considering the conventional dynamic model of squirrel
cage asynchronous generators show that integration, as such, could
degrade to the AC system performance transiently. This article
proposes a frequency or power controller which can effectively
control the transients and restore normal operation of fixed speed
induction generator quickly. Comparison of simulation results
between classical cage and doubly-fed induction generators indicate
that the doubly fed induction machine is more adaptable to
multimachine AC system. Frequency controller installed in the DFIG
system can also improve its transient profile.
Abstract: In this paper, a Neural Network based predictive
DTC algorithm is proposed .This approach is used as an
alternative to classical approaches .An appropriate riate Feed -
forward network is chosen and based on its value of
derivative electromagnetic torque ; optimal stator voltage
vector is determined to be applied to the induction motor (by
inverter). Moreover, an appropriate torque and flux observer
is proposed.
Abstract: Direct and indirect somatic embryogenesis (SE) from
petiole and leaf explants of Scaevola aemula R. Br. cv. 'Purple
Fanfare' was achieved. High frequency of somatic embryos was
obtained directly from petiole and leaf explants using an inductive
plant growth regulator signal thidiazuron (TDZ). Petiole explants
were more responsive to SE than leaves. Plants derived from somatic
embryos of petiole explants germinated more readily into plants. SE
occurred more efficiently in half-strength Murashige and Skoog
(MS) medium than in full-strength MS medium. Non-embryogenic
callus induced by 2, 4-dichlorophenoxyacetic acid was used to
investigate the feasibility of obtaining SE with TDZ as a secondary
inductive plant growth regulator (PGR) signal. Non-embryogenic
callus of S. aemula was able to convert into an “embryogenic
competent mode" with PGR signal. Protocol developed for induction
of direct and indirect somatic embryogenesis in S. aemula can
improve the large scale propagation system of the plant in future.
Abstract: In vitro plant regeneration has been successfully obtained from basal shoot explant of Vetiveria zizanioides through indirect organogenesis. The explant was cultured in Murashige & Skoog’s (MS) media supplemented with 2,4-D, IAA, and kinetin in various concentrations. Callus was well induced in media supplemented with 2 ppm 2,4-D, 1 ppm IAA, and 1 ppm kinetin. This callus was then transferred to MS media supplemented with 1 - 5 ppm of BAP for shoot regeneration. The media supplemented with 3 ppm BAP was a suitable medium for shoot induction, as well as for shoot multiplication. Rooting was well developed in shoot following transferred to half MS media containing 0.2 ppm IBA. Plantlet was then transferred to husk charcoal for acclimatization, and almost all (90%) of plantlets were survived during acclimatization.
Abstract: Wind power is among the most actively developing distributed generation (DG) technology. Majority of the wind power based DG technologies employ wind turbine induction generators (WTIG) instead of synchronous generators, for the technical advantages like: reduced size, increased robustness, lower cost, and increased electromechanical damping. However, dynamic changes of wind speed make the amount of active/reactive power injected/drawn to a WTIG embedded distribution network highly variable. This paper analyzes the effect of wind speed changes on the active and reactive power penetration to the wind energy embedded distribution network. Four types of wind speed changes namely; constant, linear change, gust change and random change of wind speed are considered in the analysis. The study is carried out by three-phase, non-linear, dynamic simulation of distribution system component models. Results obtained from the investigation are presented and discussed.
Abstract: Recent theorizations on the cognitive process of moral
judgment have focused on the role of intuitions and emotions, marking
a departure from previous emphasis on conscious, step-by-step
reasoning. My study investigated how being in a disgusted mood state
affects moral judgment.
Participants were induced to enter a disgusted mood state through
listening to disgusting sounds and reading disgusting descriptions.
Results shows that they, when compared to control who have not been
induced to feel disgust, are more likely to endorse actions that are
emotionally aversive but maximizes utilitarian return
The result is analyzed using the 'emotion-as-information' approach
to decision making. The result is consistent with the view that
emotions play an important role in determining moral judgment.
Abstract: This paper details the application of a genetic
programming framework for induction of useful classification rules
from a database of income statements, balance sheets, and cash flow
statements for North American public companies. Potentially
interesting classification rules are discovered. Anomalies in the
discovery process merit further investigation of the application of
genetic programming to the dataset for the problem domain.
Abstract: This paper focuses on PSS/E modeling of wind farms
of Doubly-fed Induction Generator (DFIG) type and their impact on
issues of power system operation. Since Wind Turbine Generators
(WTG) don-t have the same characteristics as synchronous
generators, the appropriate modeling of wind farms is essential for
transmission system operators to analyze the best options of
transmission grid reinforcements as well as to evaluate the wind
power impact on reliability and security of supply. With the high
excepted penetration of wind power into the power system a
simultaneous loss of Wind Farm generation will put at risk power
system security and reliability. Therefore, the main wind grid code
requirements concern the fault ride through capability and frequency
operation range of wind turbines. In case of grid faults wind turbines
have to supply a definite reactive power depending on the
instantaneous voltage and to return quickly to normal operation.
Abstract: This paper presents the study of induced currents and
temperature distribution in gear heated by induction process using 2D
finite element (FE) model. The model is developed by coupling
Maxwell and heat transfer equations into a multi-physics model. The
obtained results allow comparing the medium frequency (MF) and
high frequency (HF) cases and the effect of machine parameters on
the evolution of induced currents and temperature during heating.
The sensitivity study of the temperature profile is conducted and the
case hardness is predicted using the final temperature profile. These
results are validated using tests and give a good understanding of
phenomena during heating process.
Abstract: This study reports the preparation of soft magnetic ribbons of Fe-based amorphous alloys using the single-roller melt-spinning technique. Ribbon width varied from 142 mm to 213 mm and, with a thickness of approximately 22 μm 2 μm. The microstructure and magnetic properties of the ribbons were characterized by differential scanning calorimeter (DSC), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and electrical resistivity measurements (ERM). The amorphous material properties dependence of the cooling rate and nozzle pressure have uneven surface in ribbon thicknesses are investigated. Magnetic measurement results indicate that some region of the ribbon exhibits good magnetic properties, higher saturation induction and lower coercivity. However, due to the uneven surface of 213 mm wide ribbon, the magnetic responses are not uniformly distributed. To understand the transformer magnetic performances, this study analyzes the measurements of a three-phase 2 MVA amorphous-cored transformer. Experimental results confirm that the transformer with a ribbon width of 142 mm has better magnetic properties in terms of lower core loss, exciting power, and audible noise.
Abstract: This paper presents an optimal design of poly-phase induction motor using Quadratic Interpolation based Particle Swarm Optimization (QI-PSO). The optimization algorithm considers the efficiency, starting torque and temperature rise as objective function (which are considered separately) and ten performance related items including harmonic current as constraints. The QI-PSO algorithm was implemented on a test motor and the results are compared with the Simulated Annealing (SA) technique, Standard Particle Swarm Optimization (SPSO), and normal design. Some benchmark problems are used for validating QI-PSO. From the test results QI-PSO gave better results and more suitable to motor-s design optimization. Cµ code is used for implementing entire algorithms.
Abstract: Oleic acid (C18:1) play an important role in
proliferation of fat cells. In this study, the effect of oleate on cells
viability in 3T3-L1 cells (fat cells) was investigated. The 3T3-L1
cells were treated with various concentrations of oleate in the
presence of 23 mM glucose. Oleate was added to adipogenic media
(day 0) to investigate the influence of oleate on proliferation of
postconfluent preadipocytes after 24 h induction. 0.1 mM oleate
promoted cell division by increasing 33.9% number of cells from
basal control in postconfluent preadipocytes. However, there were no
significantly different in cells viability with control cells when oleate
concentrations were increased up to 0.5 mM. When added to
differentiated adipocytes (day 12) for 48 h, the number of cells
decreased as oleate concentrations increased. 92.7% of cells lost
demonstrated apoptosis and necrosis after 48 h with 0.5 mM oleate.
The fluorochrome staining was examined under fluorescence
microscopy using acridine orange and ethidium bromide double
staining. Furthermore, the presence of high lactate (60.6% increased
from basal control) released into plasma has shown the direct
cytotoxicity of 0.5 mM oleate on adipocytes.
Abstract: During recent years wind turbine technology has
undergone rapid developments. Growth in size and the optimization
of wind turbines has enabled wind energy to become increasingly
competitive with conventional energy sources. As a result today-s
wind turbines participate actively in the power production of several
countries around the world. These developments raise a number of
challenges to be dealt with now and in the future. The penetration of
wind energy in the grid raises questions about the compatibility of the
wind turbine power production with the grid. In particular, the
contribution to grid stability, power quality and behavior during fault
situations plays therefore as important a role as the reliability. In the
present work, we addressed two fault situations that have shown their
influence on the generator and the behavior of the wind over the
defects which are briefly discussed based on simulation results.
Abstract: This hypothesis shows that the induction and the
remanent of magnetic properties govern the mechanism processes of
DNA replication and the shortening of the telomere.
The solenoid–like formation of each parental DNA strand, which
exists at the initial stage of the replication process, enables an electric
charge transformation through the strand to produce a magnetic field.
The magnetic field, in turn, induces the surrounding medium to form
a new (replicated) strand by a remanent magnetisation. Through the
remanent [residual] magnetisation process, the replicated strand
possesses a similar information pattern to that of the parental strand.
In the same process, the remanent amount of magnetisation forms the
medium in which it has less of both repetitive and pattern
magnetisation than that of the parental strand, therefore the replicated
strand shows a shortening in the length of its telomeres.
Abstract: The influence of humidity and low temperature on the α- amylase activity and isoenzyme composition of grains of different wheat varieties have been studied. The identified samples of varieties have significant difference in the level of enzyme induction under the impact of high humidity and low temperature. It is proposed to use this methodological approach for testing genotypes and wheat breeding lines for resistance to pre-harvest sprouting (PHS).
Abstract: The operational behavior of a six-phase squirrel cage
induction machine with faulted stator terminals is presented in this
paper. The study is carried out using the derived mathematical model
of the machine in the arbitrary reference frame. Tests are conducted
on a 1 kW experimental machine.
Steady-state and dynamic performance are analyzed for the
machine unloaded and loaded conditions. The results shows that with
one of the stator phases experiencing either an open- circuit or short
circuit fault the machine still produces starting torque, albeit the
running performance is significantly derated.
Abstract: In this paper we report the technique of optical
induction of 2 and 3-dimensional (2D and 3D) photonic lattices in
photorefractive materials based on diffraction grating self replication
-Talbot effect. 1D and 2D different rotational symmery diffraction
masks with the periods of few tens micrometers and 532 nm cw laser
beam were used in the experiments to form an intensity modulated
light beam profile. A few hundred micrometric scale replications of
mask generated intensity structures along the beam propagation axis
were observed. Up to 20 high contrast replications were detected for
1D annular mask with 30
Abstract: Stevia rebaudiana Bertoni (natural sweetener) belongs
to Asteraceae family and can be used as substitute of artificial
sweeteners for diabetic patients. Conventionally, it is cultivated by
seeds or stem cutting, but seed viability rate is poor. A protocol for
callus induction and multiplication was developed to produce large
no. of calli in short period. Surface sterilized nodal, leaf and root
explants were cultured on Murashige and Skoog (MS) medium with
different concentrations of plant hormone like, IBA, kinetin, NAA,
2,4-D, and NAA in combination with 2,4-D. 100% callusing was
observed from leaf explants cultured on combination of NAA and
2,4-D after three weeks while with 2,4-D, only 10% callusing was
observed. Calli obtained from leaf and root explants were shiny green
while with nodal explants it was hard and brown. The present
findings deal with induction of callusing in Stevia to achieve the
rapid callus multiplication for study of steviol glycosides in callus
culture.