Abstract: In this paper we consider a nonlinear feedback
control called augmented automatic choosing control (AACC)
using the automatic choosing functions of gradient optimization
type for nonlinear systems. Constant terms which arise from sectionwise
linearization of a given nonlinear system are treated as
coefficients of a stable zero dynamics. Parameters included in the
control are suboptimally selected by minimizing the Hamiltonian
with the aid of the genetic algorithm. This approach is applied to
a field excitation control problem of power system to demonstrate
the splendidness of the AACC. Simulation results show that the
new controller can improve performance remarkably well.
Abstract: This paper addresses the problem of trajectory
tracking control of an underactuated autonomous underwater vehicle
(AUV) in the horizontal plane. The underwater vehicle under
consideration is not actuated in the sway direction, and the system
matrices are not assumed to be diagonal and linear, as often found in
the literature. In addition, the effect of constant bias of environmental
disturbances is considered. Using backstepping techniques and the
tracking error dynamics, the system states are stabilized by forcing
the tracking errors to an arbitrarily small neighborhood of zero. The
effectiveness of the proposed control method is demonstrated through
numerical simulations. Simulations are carried out for an
experimental vehicle for smooth, inertial, two dimensional (2D)
reference trajectories such as constant velocity trajectory (a circle
maneuver – constant yaw rate), and time varying velocity trajectory
(a sinusoidal path – sinusoidal yaw rate).
Abstract: In order to evaluate the Effects of dual inoculation of
Azotobacter and Mycorrhiza with Nitrogen and Phosphorus levels on
yield and yield components of spring safflower, this study was
carried out in field of Farahan university in Markazi province in
2007. A factorial in a randomized complete block design with three
replications was used inoculation of Azotobacter (with inoculation
and without inoculation) and Mycorrhiza (with inoculation and
without inoculation ) with Nitrogen and Phosphorus levels [F0= N0+
P0 (kg.ha-1), F1= N50+ P25(kg.ha-1), F2= N100+ P50(kg.ha-1) and
F3= N150+ P75 (kg.ha-1)] on spring safflower (cultivar IL-111). In
this study characteristics such as: Harvest index, Hectolitre weight,
Root dry weight, Seed yield, Mycorrhizal Colonization Root,
Number of days to maturity were assessed. Results indicated that
treatment (A0M1F3) with grain yield (1556 kg.ha-1) and treatment
(A0M1F0) with grain yield (918 kg.ha-1) were significantly superior
to the other treatments and according to calculated, inoculation seeds
in plantig date with Azotobacter and Mycorrhiza to cause increase
grain yield about 5/38 percentage. we can by inoculation safflower
seeds with Azotobacter and Mycorrhiza too easily at the time sowing
date. The purpose of this research, study and evaluation the role of
biological fixation N and P, to provide for feeds plants.
Abstract: A new Feed-Forward/Feedback Generalized
Minimum Variance Pole-placement Controller to incorporate the
robustness of classical pole-placement into the flexibility of
generalized minimum variance self-tuning controller for Single-Input
Single-Output (SISO) has been proposed in this paper. The design,
which provides the user with an adaptive mechanism, which ensures
that the closed loop poles are, located at their pre-specified positions.
In addition, the controller design which has a feed-forward/feedback
structure overcomes the certain limitations existing in similar poleplacement
control designs whilst retaining the simplicity of
adaptation mechanisms used in other designs. It tracks set-point
changes with the desired speed of response, penalizes excessive
control action, and can be applied to non-minimum phase systems.
Besides, at steady state, the controller has the ability to regulate the
constant load disturbance to zero. Example simulation results using
both simulated and real plant models demonstrate the effectiveness of
the proposed controller.
Abstract: We propose a new approach on how to obtain the approximate solutions of Hamilton-Jacobi (HJ) equations. The process of the approximation consists of two steps. The first step is to transform the HJ equations into the virtual time based HJ equations (VT-HJ) by introducing a new idea of ‘virtual-time’. The second step is to construct the approximate solutions of the HJ equations through a computationally iterative procedure based on the VT-HJ equations. It should be noted that the approximate feedback solutions evolve by themselves as the virtual-time goes by. Finally, we demonstrate the effectiveness of our approximation approach by means of simulations with linear and nonlinear control problems.
Abstract: This paper proposes a low-voltage and low-power
fully integrated digitally tuned continuous-time channel selection
filter for WiMAX applications. A 5th-order elliptic low-pass filter is
realized in a Gm-C topology. The bandwidth of the fully differential
filter is reconfigurable from 2.5MHz to 20MHz (8x) for different
requirements in WiMAX applications. The filter is simulated in a
standard 90nm CMOS process. Simulation results show the THD
(@Vout =100mVpp) is less than -66dB. The in-band ripple of the
filter is about 0.15dB. The filter consumes 1.5mW from a supply
voltage of 0.9V.
Abstract: This paper addresses the problem of asymptotic tracking
control of a linear parabolic partial differential equation with indomain
point actuation. As the considered model is a non-standard
partial differential equation, we firstly developed a map that allows
transforming this problem into a standard boundary control problem
to which existing infinite-dimensional system control methods can
be applied. Then, a combination of energy multiplier and differential
flatness methods is used to design an asymptotic tracking controller.
This control scheme consists of stabilizing state-feedback derived
from the energy multiplier method and feed-forward control based
on the flatness property of the system. This approach represents
a systematic procedure to design tracking control laws for a class
of partial differential equations with in-domain point actuation. The
applicability and system performance are assessed by simulation
studies.
Abstract: In industrial scale of Gas to Liquid (GTL) process in
Fischer-Tropsch (FT) synthesis, a part of reactor outlet gases such as
CO2 and CH4 as side reaction products, is usually recycled. In this
study, the influence of CO2 and CH4 on the performance and
selectivity of Co-Ru/Al2O3 catalyst is investigated by injection of
these gases (0-20 vol. % of feed) to the feed stream. The effect of
temperature and feed flow rate, are also inspected. The results show
that low amounts of CO2 in the feed stream, doesn`t change the
catalyst activity significantly but increasing the amount of CO2 (more
than 10 vol. %) cause the CO conversion to decrease and the
selectivity of heavy components to increase. Methane acts as an inert
gas and doesn`t affect the catalyst performance. Increasing feed flow
rate has negative effect on both CO conversion and heavy component
selectivity. By raising the temperature, CO conversion will increase
but there are more volatile components in the product. The effect of
CO2 on the catalyst deactivation is also investigated carefully and a
mechanism is suggested to explain the negative influence of CO2 on
catalyst deactivation.
Abstract: Aquatic and semi aquatic birds as a group are suited to
feed and breed in environments in which water forms a fundamental
part. These birds are biological indicator in aquatic environment,
because these birds belong to the top level of food chain in aquatic
ecosystems. There are 61 species in 14 families of aquatic and semi
aquatic birds in Iran. The birds of the Sattarkhan Lake belong to 16
species in 8 families which include 26.2 percent of total Aquatic and
semi aquatic bird species and 57% of Aquatic and semi aquatic bird's
family of Iran. Study was carried out monthly at Sattarkhan Lake
show the existence of Phalacrocorax carbo, Ardea cinerea, Egretta
alba, Egretta garzetta, Bubulcus ibis, Botaurus stellaris, Sterna
hirundo, Chlidonias leucopterus, Larus minutus, Larus argentatus,
Larus ridibunbus, Alcedo atthis, Ciconia ciconia, Plegadis
falcinellus, Circus aeruginosus, Corvus frugilegus
Abstract: The effect of different combinations of response
feedback on the performance of active control system on nonlinear
frames has been studied in this paper. To this end different feedback
combinations including displacement, velocity, acceleration and full
response feedback have been utilized in controlling the response of
an eight story bilinear hysteretic frame which has been subjected to a
white noise excitation and controlled by eight actuators which could
fully control the frame. For active control of nonlinear frame
Newmark nonlinear instantaneous optimal control algorithm has been
used which a diagonal matrix has been selected for weighting
matrices in performance index. For optimal design of active control
system while the objective has been to reduce the maximum drift to
below the yielding level, Distributed Genetic Algorithm (DGA) has
been used to determine the proper set of weighting matrices. The
criteria to assess the effect of each combination of response feedback
have been the minimum required control force to reduce the
maximum drift to below the yielding drift. The results of numerical
simulation show that the performance of active control system is
dependent on the type of response feedback where the velocity
feedback is more effective in designing optimal control system in
comparison with displacement and acceleration feedback. Also using
full feedback of response in controller design leads to minimum
control force amongst other combinations. Also the distributed
genetic algorithm shows acceptable convergence speed in solving the
optimization problem of designing active control systems.
Abstract: The aim of this study was to investigate the influence
of reaction temperature and wheat straw moisture content on the
pyrolysis product yields, in the temperature range of 475-575 °C.
Samples of straw with moisture contents from 1.5 wt % to 15.0 wt %
were fed to a bench scale Pyrolysis Centrifuge Reactor (PCR). The
experimental results show that the changes in straw moisture content
have no significant effect on the distribution of pyrolysis product
yields. The maximum bio-oil yields approximately 60 (wt %, on dry
ash free feedstock basis) was observed around 525 °C - 550 °C for all
straw moisture levels. The water content in the wet straw bio-oil was
the highest. The heating value of bio-oil and solid char were
measured and the percentages of its energy distribution were
calculated. The energy distributions of bio-oil, char and gas were 56-
69 % 24-33 %, and 2-19 %, respectively.
Abstract: In this study, a mathematical model was proposed and
the accuracy of this model was assessed to predict the growth of
Pseudomonas aeruginosa and rhamnolipid production under nitrogen
limiting (sodium nitrate) fed-batch fermentation. All of the
parameters used in this model were achieved individually without
using any data from the literature.
The overall growth kinetic of the strain was evaluated using a
dual-parallel substrate Monod equation which was described by
several batch experimental data. Fed-batch data under different
glycerol (as the sole carbon source, C/N=10) concentrations and feed
flow rates were used to describe the proposed fed-batch model and
other parameters. In order to verify the accuracy of the proposed
model several verification experiments were performed in a vast
range of initial glycerol concentrations. While the results showed an
acceptable prediction for rhamnolipid production (less than 10%
error), in case of biomass prediction the errors were less than 23%. It
was also found that the rhamnolipid production by P. aeruginosa was
more sensitive at low glycerol concentrations.
Based on the findings of this work, it was concluded that the
proposed model could effectively be employed for rhamnolipid
production by this strain under fed-batch fermentation on up to 80 g l-
1 glycerol.
Abstract: A shaft-type activated sludge reactor has been
developed in order to study the feasibility of high-rate wastewater
treatment. The reactor having volume of about 14.5 L was operated
with the acclimated mixed activated sludge under batch and
continuous mode using a synthetic wastewater as feed. The batch
study was performed with varying chemical oxygen demand (COD)
concentrations of 1000–3500 mg·L-1 for a batch period up to 9 h. The
kinetic coefficients: Ks, k, Y and kd were obtained as 2040.2 mg·L-1
and 0.105 h-1, 0.878 and 0.0025 h-1 respectively from Monod-s
approach. The continuous study showed a stable and steady state
operation for a hydraulic retention time (HRT) of 8 h and influent
COD of about 1000 mg·L-1. A maximum COD removal efficiency of
about 80% was attained at a COD loading rate and food-tomicroorganism
(F/M) ratio (COD basis) of 3.42 kg·m-3d-1 and 1.0
kg·kg-1d-1 respectively under a HRT of 8 h. The reactor was also
found to handle COD loading rate and F/M ratio of 10.8 kg·m-3d-1
and 2.20 kg·kg-1d-1 respectively showing a COD removal efficiency
of about 46%.
Abstract: Polyphenolics and sugar are the components of many
fruit juices. In this work, the performance of ultra-filtration (UF) for
separating phenolic compounds from apple juice was studied by
performing batch experiments in a membrane module with an area of
0.1 m2 and fitted with a regenerated cellulose membrane of 1 kDa
MWCO. The effects of various operating conditions: transmembrane
pressure (3, 4, 5 bar), temperature (30, 35, 40 ºC), pH (2, 3, 4, 5),
feed concentration (3, 5, 7, 10, 15 ºBrix for apple juice) and feed flow
rate (1, 1.5, 1.8 L/min) on the performance were determined.
The optimum operating conditions were: transmembrane pressure
4 bar, temperature 30 ºC, feed flow rate 1 – 1.8 L/min, pH 3 and 10
Brix (apple juice). After performing ultrafiltration under these
conditions, the concentration of polyphenolics in retentate was
increased by a factor of up to 2.7 with up to 70% recovered in the
permeate and with approx. 20% of the sugar in that stream..
Application of diafiltration (addition of water to the concentrate) can
regain the flux by a factor of 1.5, which has been decreased due to
fouling. The material balance performed on the process has shown
the amount of deposits on the membrane and the extent of fouling in
the system. In conclusion, ultrafiltration has been demonstrated as a
potential technology to separate the polyphenolics and sugars from
their mixtures and can be applied to remove sugars from fruit juice.
Abstract: A process flowsheet was developed in ChemCad 6.4
to study the effect of feed moisture contents on the pre-esterification
of waste oils. Waste oils were modelled as a mixture of triolein
(90%), oleic acid (5%) and water (5%). The process mainly consisted
of feed drying, pre-esterification reaction and methanol recovery. The
results showed that the process energy requirements would be
minimized when higher degrees of feed drying and higher preesterification
reaction temperatures are used.
Abstract: Dried tomato peel (DTP) was tested in vivo (n=10) in 42 week-old laying hens at rates of 0, 40, 70, 100 and 130g/kg DM feed. Laying hens were fed in group 120 g DM/day/animal for 26 days. After 21 days, feed intake was not affected after DTP incorporation (97% of the offered feed in the five groups). Laying rate was not significantly different after DTP incorporation at 4 and 10% from the control group. Egg yolk resulting from DTP-enriched diets, contained lower amounts of cholesterol (14 to 17mg/g) and triglyceride (188mg/g) compared to the control group (22 and 241 mg/g, respectively) (P
Abstract: Active vibration control is an important problem in
structures. The objective of active vibration control is to reduce the vibrations of a system by automatic modification of the system-s
structural response. In this paper, the modeling and design of a fast
output sampling feedback controller for a smart flexible beam system embedded with shear sensors and actuators for SISO system using
Timoshenko beam theory is proposed. FEM theory, Timoshenko beam theory and the state space techniques are used to model the
aluminum cantilever beam. For the SISO case, the beam is divided into 5 finite elements and the control actuator is placed at finite
element position 1, whereas the sensor is varied from position 2 to 5, i.e., from the nearby fixed end to the free end. Controllers are
designed using FOS method and the performance of the designed FOS controller is evaluated for vibration control for 4 SISO models
of the same plant. The effect of placing the sensor at different locations on the beam is observed and the performance of the
controller is evaluated for vibration control. Some of the limitations of the Euler-Bernoulli theory such as the neglection of shear and
axial displacement are being considered here, thus giving rise to an accurate beam model. Embedded shear sensors and actuators have
been considered in this paper instead of the surface mounted sensors
and actuators for vibration suppression because of lot of advantages. In controlling the vibration modes, the first three dominant modes of
vibration of the system are considered.
Abstract: Rotation or tilt present in an image capture by digital
means can be detected and corrected using Artificial Neural Network
(ANN) for application with a Face Recognition System (FRS). Principal
Component Analysis (PCA) features of faces at different angles
are used to train an ANN which detects the rotation for an input image
and corrected using a set of operations implemented using another
system based on ANN. The work also deals with the recognition
of human faces with features from the foreheads, eyes, nose and
mouths as decision support entities of the system configured using
a Generalized Feed Forward Artificial Neural Network (GFFANN).
These features are combined to provide a reinforced decision for
verification of a person-s identity despite illumination variations. The
complete system performing facial image rotation detection, correction
and recognition using re-enforced decision support provides a
success rate in the higher 90s.
Abstract: The objective of this study was to investigate hydrogen production from alcohol wastewater by anaerobic sequencing batch reactor (ASBR) under thermophillic operation. The ASBR unit used in this study had a liquid holding volume of 4 L and was operated at 6 cycles per day. The seed sludge taken from an upflow anaerobic sludge blanket unit treating the same wastewater was boiled at 95 °C for 15 min before being fed to the ASBR unit. The ASBR system was operated at different COD loading rates at a thermophillic temperature (55 °C), and controlled pH of 5.5. When the system was operated under optimum conditions (providing maximum hydrogen production performance) at a feed COD of 60 000 mg/l, and a COD loading rate of 68 kg/m3 d, the produced gas contained 43 % H2 content in the produced gas. Moreover, the hydrogen yield and the specific hydrogen production rate (SHPR) were 130 ml H2/g COD removed and 2100 ml H2/l d, respectively.
Abstract: In Algeria, now, the oil pumping plants are fed with electric power by independent local sources. This type of feeding has many advantages (little climatic influence, independent operation). However it requires a qualified maintenance staff, a rather high frequency of maintenance and repair and additional fuel costs. Taking into account the increasing development of the national electric supply network (Sonelgaz), a real possibility of transfer of the local sources towards centralized sources appears.These latter cannot only be more economic but more reliable than the independent local sources as well. In order to carry out this transfer, it is necessary to work out an optimal strategy to rebuilding these networks taking in account the economic parameters and the indices of reliability.