Abstract: Optimal reactive power flow is an optimization problem
with one or more objective of minimizing the active power losses for
fixed generation schedule. The control variables are generator bus
voltages, transformer tap settings and reactive power output of the
compensating devices placed on different bus bars. Biogeography-
Based Optimization (BBO) technique has been applied to solve
different kinds of optimal reactive power flow problems subject
to operational constraints like power balance constraint, line flow
and bus voltages limits etc. BBO searches for the global optimum
mainly through two steps: Migration and Mutation. In the present
work, BBO has been applied to solve the optimal reactive power
flow problems on IEEE 30-bus and standard IEEE 57-bus power
systems for minimization of active power loss. The superiority of the
proposed method has been demonstrated. Considering the quality of
the solution obtained, the proposed method seems to be a promising
one for solving these problems.
Abstract: Nonlinear finite element method with eight noded
isoparametric quadrilateral element is used for prediction of loaddeformation
behavior including bearing capacity of foundations.
Modified generalized plasticity model with non-associated flow rule
is applied for analysis of soil-footing system. Also Von Mises and
Tresca criterions are used for simulation of soil behavior. Modified
generalized plasticity model is able to simulate load-deformation
including softening behavior. Localization phenomena are considered
by different meshes. Localization phenomena have not been seen in
the examples. Predictions by modified generalized plasticity model
show good agreement with laboratory data and theoretical prediction
in comparison the other models.
Abstract: We study a new technique for optimal data compression
subject to conditions of causality and different types of memory. The
technique is based on the assumption that some information about
compressed data can be obtained from a solution of the associated
problem without constraints of causality and memory. This allows
us to consider two separate problem related to compression and decompression
subject to those constraints. Their solutions are given
and the analysis of the associated errors is provided.
Abstract: The present work deals with the stabilisation of
organic clay using hydrated lime. Artificial organic clays were
prepared by adding kaolin and different humic acid contents. Results
given by physical testing show that the presence of humic acid has a
drawback effect on the untreated organic clay. The decrease in
specific gravity value was accompanied by a decrease in dry density
and plasticity of clay at higher humic acid contents. Significant
increase in shear strength at 7 days of curing period is observed in the
lime-treated samples up to 5% lime content. However shear strength
of lime-treated organic clay decreases at longer curing periods. The
results given by laboratory testing is further verified by
microstructure analysis. Based on the results obtained in this study, it
can be concluded that the presence of more than 1.5% humic acid
reduces significantly the efficiency of lime stabilization in organic
clays.
Abstract: This paper presents a developed method for
controlling multi-renewable energy generators. The control system
depends basically on three sensors (wind anemometer, solar sensor,
and voltage sensor). These sensors represent PLC-s analogue inputs.
Controlling the output voltage supply can be achieved by an
enhanced method of interlocking between the renewable energy
generators, depending on those sensors and output contactors.
Abstract: In this paper a procedure for the split-pipe design of looped water distribution network based on the use of simulated annealing is proposed. Simulated annealing is a heuristic-based search algorithm, motivated by an analogy of physical annealing in solids. It is capable for solving the combinatorial optimization problem. In contrast to the split-pipe design that is derived from a continuous diameter design that has been implemented in conventional optimization techniques, the split-pipe design proposed in this paper is derived from a discrete diameter design where a set of pipe diameters is chosen directly from a specified set of commercial pipes. The optimality and feasibility of the solutions are found to be guaranteed by using the proposed method. The performance of the proposed procedure is demonstrated through solving the three well-known problems of water distribution network taken from the literature. Simulated annealing provides very promising solutions and the lowest-cost solutions are found for all of these test problems. The results obtained from these applications show that simulated annealing is able to handle a combinatorial optimization problem of the least cost design of water distribution network. The technique can be considered as an alternative tool for similar areas of research. Further applications and improvements of the technique are expected as well.
Abstract: This paper addresses one important aspect of
combustion system analysis, the spray evaporation and
dispersion modeling. In this study we assume an empty
cylinder which is as a simulator for a ramjet engine and the
cylinder has been studied by cold flow. Four nozzles have the
duties of injection which are located in the entrance of
cylinder. The air flow comes into the cylinder from one side
and injection operation will be done. By changing injection
velocity and entrance air flow velocity, we have studied
droplet sizing and efficient mass fraction of fuel vapor near
and at the exit area. We named the mass of fuel vapor inside
the flammability limit as the efficient mass fraction. Further,
we decreased the initial temperature of fuel droplets and we
have repeated the investigating again. To fulfill the calculation
we used a modified version of KIVA-3V.
Abstract: State-dependent Riccati equation based controllers are
becoming increasingly popular because of having attractive
properties like optimality, stability and robustness. This paper focuses
on the design of a roll autopilot for a fin stabilized and canard
controlled 122mm artillery rocket using state-dependent Riccati
equation technique. Initial spin is imparted to rocket during launch
and it quickly decays due to straight tail fins. After the spin phase, the
roll orientation of rocket is brought to zero with the canard deflection
commands generated by the roll autopilot. Roll autopilot has been
developed by considering uncoupled roll, pitch and yaw channels.
The canard actuator is modeled as a second-order nonlinear system.
Elements of the state weighing matrix for Riccati equation have been
chosen to be state dependent to exploit the design flexibility offered
by the Riccati equation technique. Simulation results under varying
conditions of flight demonstrate the wide operating range of the
proposed autopilot.
Abstract: The principal objective of a water treatment plant is to
produce water that satisfies a set of drinking water quality standards
at a reasonable price to the consumers. The gravel-bed flocculator
provide a simple and inexpensive design for flocculation in small
water treatment plants (less than 5000 m3/day capacity). The packed
bed of gravel provides ideal conditions for the formation of compact
settleable flocs because of continuous recontact provided by the
sinuous flow of water through the interstices formed by the gravel.
The field data which were obtained from the operation of the
water supply treatment unit cover the physical, chemical and
biological water qualities of the raw and settled water as obtained by
the operation of the treatment unit. The experiments were carried out
with the aim of assessing the efficiency of the gravel filter in
removing the turbidity, pathogenic bacteria, from the raw water. The
water treatment plant, which was constructed for the treatment of
river water, was in principle a rapid sand filter.
The results show that the average value of the turbidity level of
the settled water was 4.83 NTU with a standard deviation of turbidity
2.893 NTU. This indicated that the removal efficiency of the
sedimentation tank (gravel filter) was about 67.8 %. for pH values
fluctuated between 7.75 and 8.15, indicating the alkaline nature of
the raw water of the river Shatt Al-Hilla, as expected. Raw water pH
is depressed slightly following alum coagulation. The pH of the
settled water ranged from 7.75 to a maximum of 8.05.
The bacteriological tests which were carried out on the water
samples were: total coliform test, E-coli test, and the plate count test.
In each test the procedure used was as outlined in the Standard
Methods for the Examination of Water and Wastewater (APHA,
AWWA, and WPCF, 1985). The gravel filter exhibit a low
performance in removing bacterial load. The percentage bacterial
removal, which is maximum for total plate count (19%) and
minimum for total coliform (16.82%).
Abstract: This article presents new current-mode oscillator circuits using CDTAs which is designed from block diagram. The proposed circuits consist of two CDTAs and two grounded capacitors. The condition of oscillation and the frequency of oscillation can be adjusted by electronic method. The circuits have high output impedance and use only grounded capacitors without any external resistor which is very appropriate to future development into an integrated circuit. The results of PSPICE simulation program are corresponding to the theoretical analysis.
Abstract: Col is a classic combinatorial game played on graphs
and to solve a general instance is a PSPACE-complete problem.
However, winning strategies can be found for some specific graph
instances. In this paper, the solution of Col on complete k-ary trees
is presented.
Abstract: This paper presents the experimental results of
discharge current phenomena on various humidity, temperature,
pressure and pollutant conditions of epoxy resin specimen. The
leakage distance of specimen was 3 cm, that it was supplied by high
voltage. The polluted condition was given with NaCl artificial
pollutant. The conducted measurements were discharge current and
applied voltage. The specimen was put in a hermetically sealed
chamber, and the current waveforms were analyzed with FFT.
The result indicated that on discharge condition, the fifth
harmonics still had dominant, rather than third one. The third
harmonics tent to be appeared on low pressure heavily polluted
condition, and followed by high humidity heavily polluted condition.
On the heavily polluted specimen, the peaks discharge current points
would be high and more frequent. Nevertheless, the specimen still
had capacitive property. Besides that, usually discharge current
points were more frequent. The influence of low pressure was still
dominant to be easier to discharge. The non-linear property would be
appear explicitly on low pressure and heavily polluted condition.
Abstract: Temperature dependence of force of gravitation is one
of the fundamental problems of physics. This problem has got special
value in connection with that the general theory of relativity,
supposing the weakest positive influence of a body temperature on its
weight, actually rejects an opportunity of measurement of negative
influence of temperature on gravity in laboratory conditions. Really,
the recognition of negative temperature dependence of gravitation,
for example, means basic impossibility of achievement of a
singularity («a black hole») at a gravitational collapse. Laboratory
experiments with exact weighing the heated up metal samples,
indicating negative influence temperatures of bodies on their physical
weight are described. Influence of mistakes of measurements is
analyzed. Calculations of distribution of temperature in volume of the
bar, agreed with experimental data of time dependence of weight of
samples are executed. The physical substantiation of negative
temperature dependence of weight of the bodies, based on correlation
of acceleration at thermal movement of micro-particles of a body and
its absolute temperature, are given.
Abstract: With the growth of electricity generation from gas
energy gas pipeline reliability can substantially impact the electric
generation. A physical disruption to pipeline or to a compressor
station can interrupt the flow of gas or reduce the pressure and lead
to loss of multiple gas-fired electric generators, which could
dramatically reduce the supplied power and threaten the power
system security. Gas pressure drops during peak loading time on
pipeline system, is a common problem in network with no enough
transportation capacity which limits gas transportation and causes
many problem for thermal domain power systems in supplying their
demand. For a feasible generation scheduling planning in networks
with no sufficient gas transportation capacity, it is required to
consider gas pipeline constraints in solving the optimization problem
and evaluate the impacts of gas consumption in power plants on gas
pipelines operating condition. This paper studies about operating of
gas fired power plants in critical conditions when the demand of gas
and electricity peak together. An integrated model of gas and electric
model is used to consider the gas pipeline constraints in the economic
dispatch problem of gas-fueled thermal generator units.
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: The paper presents a complete discrete statistical framework, based on a novel vector quantization (VQ) front-end process. This new VQ approach performs an optimal distribution of VQ codebook components on HMM states. This technique that we named the distributed vector quantization (DVQ) of hidden Markov models, succeeds in unifying acoustic micro-structure and phonetic macro-structure, when the estimation of HMM parameters is performed. The DVQ technique is implemented through two variants. The first variant uses the K-means algorithm (K-means- DVQ) to optimize the VQ, while the second variant exploits the benefits of the classification behavior of neural networks (NN-DVQ) for the same purpose. The proposed variants are compared with the HMM-based baseline system by experiments of specific Arabic consonants recognition. The results show that the distributed vector quantization technique increase the performance of the discrete HMM system.
Abstract: The relics of traditional folk culture in Kazakhstan are ceremonies or their fragments - such as weddings, funerals, shamanism. The world of spiritual creatures, spirits-protectors, spirits-helpers, injury spirits, spirits of illnesses, etc., is described in detail in shamanic rites (in Kazakh culture it is called bakslyk). The study of these displays of folk culture, which reflect the peoples` ethnic mentality or notions about the structure, values and hierarchies of the universe, includes collection and recording of the field materials and their interpretation, i.e. reconstruction of those meanings which were initially embodied or “coded" in folklore. A distinctive feature of Kazakh nomadic culture is its self-preservation and actualization, almost untouched the ancient mythologies of the world, in particular, the mythologies connected with music, musical instruments and the creator of music. Within the frameworks of the traditional culture the word and the music keep the sacral meaning. The ritual melodies and what they carry – the holly, and at the same time unexplored, powerful and threatening, uncontrolled by people world – keep on attributing the soul to all, connected with culture.
Abstract: In this paper we present an efficient method for inverting an ideal in the ideal class group of a Cab curve by extending the method which is presented in [3]. More precisely we introduce a useful generator for the inverse ideal as a K[X]-module.
Abstract: The aim of this study was to investigate the effect of blood viscosity on the radial pulse wave. For this, we obtained the radial pulse wave of 15 males with abnormal high hematocrit level and 47 males with normal hematocrit level at the age of thirties and forties. Various variables of the radial pulse wave between two groups were analyzed and compared by Student's T test. There are significant differences in several variables about height, time and area of the pulse wave. The first peak of the radial pulse wave was higher in abnormal high hematocrit group, but the third peak was higher and longer in normal hematocrit group. Our results suggest that the radial pulse wave can be used for diagnosis of high blood viscosity and more clinical application.
Abstract: In this research sodium bicarbonate (NaHCO3) was introduced to generate carbon dioxide gas (CO2) to the existing nitrogen gas (N2) of elastomeric foam, to lower thermal conductivity (K). Various loadings of NaHCO3 (0 to 60 phr) were added into the azodicarbonamide (AZC)-containing compound and its properties were then determined. Two vulcanization methods, i.e., hot air and infrared (IR), were employed and compared in this study. Results revealed that compound viscosity tended to increase slightly with increasing NaHCO3 content but cure time was delayed. The effect of NaHCO3 content on thermal conductivity depended on the vulcanization method. For hot air method, the thermal conductivity was insignificantly changed with increasing NaHCO3 up to 40 phr whereas it tended to decrease gradually for IR method. At higher NaHCO3 content (60 phr), unexpected increase of thermal conductivity was observed. The water absorption was also determined and foam structures were then used to explain the results.