Abstract: This paper presents the voltage regulation scheme of
D-STATCOM under three-phase faults. It consists of the voltage
detection and voltage regulation schemes in the 0dq reference. The
proposed control strategy uses the proportional controller in which
the proportional gain, kp, is appropriately adjusted by using genetic
algorithms. To verify its use, a simplified 4-bus test system is situated
by assuming a three-phase fault at bus 4. As a result, the DSTATCOM
can resume the load voltage to the desired level within
1.8 ms. This confirms that the proposed voltage regulation scheme
performs well under three-phase fault events.
Abstract: In this work, sorption of nickel from aqueous solution on hypnea valentiae, red macro algae, was investigated. Batch experiments have been carried out to find the effect of various parameters such as pH, temperature, sorbent dosage, metal concentration and contact time on the sorption of nickel using hypnea valentiae. Response surface methodology (RSM) is employed to optimize the process parameters. Based on the central composite design, quadratic model was developed to correlate the process variables to the response. The most influential factor on each experimental design response was identified from the analysis of variance (ANOVA). The optimum conditions for the sorption of nickel were found to be: pH – 5.1, temperature – 36.8oC, sorbent dosage – 5.1 g/L, metal concentration – 100 mg/L and contact time – 30 min. At these optimized conditions the maximum removal of nickel was found to be 91.97%. A coefficient of determination R2 value 0.9548 shows the fitness of response surface methodology in this work.
Abstract: The stop watch is used to measure the time required
for a certain event. This is different from normal clocks in many
ways, one of which is the accuracy of time. The stop watch requires
much more accuracy than the normal clocks. In this paper, an
ATmega8535 microcontroller was used to control the stop watch, by
which perfect accuracy can be ensured. For compiling the C code and
for loading the compiled .hex file into the microcontroller, AVR
studio and PonyProg were used respectively. The stop watch is also
different from traditional stop watches, as it contains two different
timing modes namely 'Split timing' and 'Lap timing'.
Abstract: A numerical study has been conducted to investigate the influence of fin pitch and relative humidity on the heat transfer performance of the fin-and-tube heat exchangers having plain fin geometry under dehumidifying conditions. The analysis is done using the ratio between the heat transfer coefficients in totally wet conditions and those in totally dry conditions using the appropriate correlations for both dry and wet conditions. For a constant relative humidity, it is found that the heat transfer coefficient increases with the increase of the air frontal velocity. By contrast, the fin efficiency decreases when the face velocity is increased. Apparently, this phenomenon is attributed to the path of condensate drainage. For the influence of relative humidity, the results showed an increase in heat transfer performance and a decrease in wet fin efficiency when relative humidity increases. This is due to the higher amount of mass transfer encountered at higher relative humidity. However, it is found that the effect of fin pitch on the heat transfer performance depends strongly on the face velocity. At lower frontal velocity the heat transfer increases with fin pitch. Conversely, an increase in fin pitch gives lower heat transfer coefficients when air velocity is increased.
Abstract: A new and cost effective RP-HPLC method was
developed and validated for simultaneous analysis of non steroidal
anti inflammatory dugs Diclofenac sodium (DFS), Flurbiprofen
(FLP) and an opioid analgesic Tramadol (TMD) in advanced drug
delivery systems (Liposome and Microcapsules), marketed brands
and human plasma. Isocratic system was employed for the flow of
mobile phase consisting of 10 mM sodium dihydrogen phosphate
buffer and acetonitrile in molar ratio of 67: 33 with adjusted pH of
3.2. The stationary phase was hypersil ODS column (C18, 250×4.6
mm i.d., 5 μm) with controlled temperature of 30 C°. DFS in
liposomes, microcapsules and marketed drug products was
determined in range of 99.76-99.84%. FLP and TMD in
microcapsules and brands formulation were 99.78 - 99.94 % and
99.80 - 99.82 %, respectively. Single step liquid-liquid extraction
procedure using combination of acetonitrile and trichloroacetic acid
(TCA) as protein precipitating agent was employed. The detection
limits (at S/N ratio 3) of quality control solutions and plasma samples
were 10, 20, and 20 ng/ml for DFS, FLP and TMD, respectively.
The Assay was acceptable in linear dynamic range. All other
validation parameters were found in limits of FDA and ICH method
validation guidelines. The proposed method is sensitive, accurate and
precise and could be applicable for routine analysis in
pharmaceutical industry as well as in human plasma samples for
bioequivalence and pharmacokinetics studies.
Abstract: This paper proposes an adaptive sliding mode
controller which combines adaptive control and sliding
mode control to control a nonlinear robotic manipulator
with uncertain parameters. We use an adaptive algorithm
based on the concept of sliding mode control to alleviate the
chattering phenomenon of control input. Adaptive laws are
developed to obtain the gain of switching input and the
boundary layer parameters. The stability and convergence
of the robotic manipulator control system are guaranteed
by applying the Lyapunov theorem. Simulation results
demonstrate that the chattering of control input can be
alleviated effectively. The proposed controller scheme can
assure robustness against a large class of uncertainties and
achieve good trajectory tracking performance.
Abstract: In this study we present the effect of elevated
temperatures from 300K to 400K on the electrical properties of
copper Phthalocyanine (CuPc) based organic field effect transistors
(OFET). Thin films of organic semiconductor CuPc (40nm) and
semitransparent Al (20nm) were deposited in sequence, by vacuum
evaporation on a glass substrate with previously deposited Ag source
and drain electrodes with a gap of 40 μm. Under resistive mode of
operation, where gate was suspended it was observed that drain
current of this organic field effect transistor (OFET) show an
increase with temperature. While in grounded gate condition metal
(aluminum) – semiconductor (Copper Phthalocyanine) Schottky
junction dominated the output characteristics and device showed
switching effect from low to high conduction states like Zener diode
at higher bias voltages. This threshold voltage for switching effect
has been found to be inversely proportional to temperature and shows
an abrupt decrease after knee temperature of 360K. Change in
dynamic resistance (Rd = dV/dI) with respect to temperature was
observed to be -1%/K.
Abstract: Prediction of sinusoidal signals with time-varying
frequencies has been an important research topic in power electronics
systems. To solve this problem, we propose a new fuzzy
predictive filtering scheme, which is based on a Finite Impulse
Response (FIR) filter bank. Fuzzy logic is introduced here to provide
appropriate interpolation of individual filter outputs. Therefore,
instead of regular 'hard' switching, our method has the advantageous
'soft' switching among different filters. Simulation
comparisons between the fuzzy predictive filtering and conventional
filter bank-based approach are made to demonstrate that the
new scheme can achieve an enhanced prediction performance for
slowly changing sinusoidal input signals.
Abstract: Mycophenolic acid (MPA) is a secondary metabolite
produced by Penicillium brevicompactum, which has antibiotic and
immunosuppressive properties. In this study, the first, mycophenolic
acid was produced in a fermentation process by Penicillium
brevicompactum MUCL 19011 in shake flask using a base medium.
The maximum MPA production, product yield and productivity of
process were 1.379 g/L, 18.6 mg/g glucose and 4.9 mg/L. h,
respectively. Also the glucose consumption, biomass and MPA
production profiles were investigated during batch cultivation.
Obtained results showed that MPA production starts approximately
after 180 hours and reaches to a maximum at 280 h. In the next step,
the effects of some various concentrations of enzymatically
hydrolyzed casein on MPA production were evaluated. Maximum
MPA production, product yield and productivity as 3.63 g/L, 49
mg/g glucose and 12.96 mg/L.h, respectively were obtained with
using 30 g/L enzymatically hydrolyzed casein in culture medium.
These values show an enhanced MPA production, product yield and
process productivity pr as 116.8%, 132.8% and 163.2%, respectively.
Abstract: Measuring the effect of perinatal lead exposure on learning ability of offspring is considered as a sensitive and selective index for providing an early marker for central nervous system damage produced by this toxic metal. A total of 35 Sprague-Dawley adult rats were used to investigate the effect of lead acetate toxicity on behavioral patterns of adult female rats and learning ability of offspring. Rats were allotted into 4 groups, group one received 1g/l lead acetate (n=10), group two received 1.5g/l lead acetate (n=10), group three received 2g/l lead acetate in drinking water (n=10) and control group did not receive lead acetate (n=5) from 8th day of pregnancy till weaning of pups.
The obtained results revealed a dose dependent increase in the feeding time, drinking frequency, licking frequency, scratching frequency, licking litters, nest building and retrieving frequencies, while standing time increased significantly in rats treated with 1.5g/l lead acetate than other treated groups and control, on contrary lying time decreased gradually in a dose dependent manner. Moreover, movement activities were higher in rats treated with 1g/l lead acetate than other treated groups and control. Furthermore, time spent in closed arms was significantly lower in rats given 2g/l lead acetate than other treated groups, while, they spent significantly much time spent in open arms than other treated groups which could be attributed to occurrence of adaptation. Furthermore, number of entries in open arms was dose dependent. However, the ratio between open/closed arms revealed a significant decrease in rats treated with 2g/l lead acetate than control group.
Abstract: Strict stability can present the rate of decay of the
solution, so more and more investigators are beginning to study the
topic and some results have been obtained. However, there are few
results about strict stability of stochastic differential equations. In
this paper, using Lyapunov functions and Razumikhin technique, we
have gotten some criteria for the strict stability of impulsive stochastic
functional differential equations with markovian switching.
Abstract: This paper discusses a new heavy tailed distribution based data hiding into discrete cosine transform (DCT) coefficients of image, which provides statistical security as well as robustness against steganalysis attacks. Unlike other data hiding algorithms, the proposed technique does not introduce much effect in the stegoimage-s DCT coefficient probability plots, thus making the presence of hidden data statistically undetectable. In addition the proposed method does not compromise on hiding capacity. When compared to the generic block DCT based data-hiding scheme, our method found more robust against a variety of image manipulating attacks such as filtering, blurring, JPEG compression etc.
Abstract: Continuously variable transmission (CVT) is a type of
automatic transmission that can change the gear ratio to any arbitrary
setting within the limits. The most common type of CVT operates on
a pulley system that allows an infinite variability between highest and
lowest gears with no discrete steps. However, the current CVT
system with hydraulic actuation method suffers from the power loss.
It needs continuous force for the pulley to clamp the belt and hold the
torque resulting in large amount of energy consumption. This study
focused on the development of an electromechanical actuated control
CVT to eliminate the problem that faced by the existing CVT. It is
conducted with several steps; computing and selecting the
appropriate sizing for stroke length, lead screw system and etc. From
the visual observation it was found that the CVT system of this
research is satisfactory.
Abstract: Success is a European project that will implement several clean transport offers in three European cities and evaluate the environmental impacts. The goal of these measures is to improve urban mobility or the displacement of residents inside cities. For e.g. park and ride, electric vehicles, hybrid bus and bike sharing etc. A list of 28 criteria and 60 measures has been established for evaluation of these transport projects. The evaluation criteria can be grouped into: Transport, environment, social, economic and fuel consumption. This article proposes a decision support system based that encapsulates a hybrid approach based on fuzzy logic, multicriteria analysis and belief theory for the evaluation of impacts of urban mobility solutions. A web-based tool called DeSSIA (Decision Support System for Impacts Assessment) has been developed that treats complex data. The tool has several functionalities starting from data integration (import of data), evaluation of projects and finishes by graphical display of results. The tool development is based on the concept of MVC (Model, View, and Controller). The MVC is a conception model adapted to the creation of software's which impose separation between data, their treatment and presentation. Effort is laid on the ergonomic aspects of the application. It has codes compatible with the latest norms (XHTML, CSS) and has been validated by W3C (World Wide Web Consortium). The main ergonomic aspect focuses on the usability of the application, ease of learning and adoption. By the usage of technologies such as AJAX (XML and Java Script asynchrones), the application is more rapid and convivial. The positive points of our approach are that it treats heterogeneous data (qualitative, quantitative) from various information sources (human experts, survey, sensors, model etc.).
Abstract: This paper regards the phenomena of intensive suburbanization and urbanization in Olomouc city and in Olomouc region in general for the period of 1986–2009. A Remote Sensing approach that involves tracking of changes in Land Cover units is proposed to quantify the urbanization state and trends in temporal and spatial aspects. It actually consisted of two approaches, Experiment 1 and Experiment 2 which implied two different image classification solutions in order to provide Land Cover maps for each 1986–2009 time split available in the Landsat image set. Experiment 1 dealt with the unsupervised classification, while Experiment 2 involved semi- supervised classification, using a combination of object-based and pixel-based classifiers. The resulting Land Cover maps were subsequently quantified for the proportion of urban area unit and its trend through time, and also for the urban area unit stability, yielding the relation of spatial and temporal development of the urban area unit. Some outcomes seem promising but there is indisputably room for improvements of source data and also processing and filtering.
Abstract: The current paper presents a numerical approach in solving the conjugate heat transfer problems. A heat conduction code is coupled internally with a computational fluid dynamics solver for developing a couple conjugate heat transfer solver. Methodology of treating non-matching meshes at interface has also been proposed. The validation results of 1D and 2D cases for the developed conjugate heat transfer code have shown close agreement with the solutions given by analysis.
Abstract: Researches on the general rules of temperature field
changing and their effects on the bridge in construction are necessary.
This paper investigated the rules of temperature field changing and its
effects on bridge using onsite measurement and computational
analysis. Guanyinsha Bridge was used as a case study in this research.
The temperature field was simulated in analyses. The effects of certain
boundary conditions such as sun radiance, wind speed, and model
parameters such as heat factor and specific heat on temperature field
are investigated. Recommended values for these parameters are
proposed. The simulated temperature field matches the measured
observations with high accuracy. At the same time, the stresses and
deflections of the bridge computed with the simulated temperature
field matches measured values too. As a conclusion, the temperature
effect analysis of reinforced concrete box girder can be conducted
directly based on the reliable weather data of the concerned area.
Abstract: Different types of aggregation operators such as the
ordered weighted quasi-arithmetic mean (Quasi-OWA) operator and
the normalized Hamming distance are studied. We introduce the use
of the OWA operator in generalized distances such as the quasiarithmetic
distance. We will call these new distance aggregation the
ordered weighted quasi-arithmetic distance (Quasi-OWAD) operator.
We develop a general overview of this type of generalization and
study some of their main properties such as the distinction between
descending and ascending orders. We also consider different families
of Quasi-OWAD operators such as the Minkowski ordered weighted
averaging distance (MOWAD) operator, the ordered weighted
averaging distance (OWAD) operator, the Euclidean ordered
weighted averaging distance (EOWAD) operator, the normalized
quasi-arithmetic distance, etc.
Abstract: This paper proposed classification models that would
be used as a proxy for hard disk drive (HDD) functional test equitant
which required approximately more than two weeks to perform the
HDD status classification in either “Pass" or “Fail". These models
were constructed by using committee network which consisted of a
number of single neural networks. This paper also included the
method to solve the problem of sparseness data in failed part, which
was called “enforce learning method". Our results reveal that the
constructed classification models with the proposed method could
perform well in the sparse data conditions and thus the models,
which used a few seconds for HDD classification, could be used to
substitute the HDD functional tests.
Abstract: Higher education has an important role to play in
advocating environmentalism. Given this responsibility, the goal of
higher education should therefore be to develop graduates with the
knowledge, skills and values related to environmentalism. However,
research indicates that there is a lack of consciousness amongst
graduates on the need to be more environmentally aware, especially
when it comes to applying the appropriate knowledge and skills
related to environmentalism. Although institutions of higher learning
do include environmental parameters within their undergraduate and
postgraduate academic programme structures, the environmental
boundaries are usually confined to specific engineering majors within
an engineering programme. This makes environmental knowledge,
skills and values exclusive to certain quarters of the higher education
system. The incorporation of environmental literacy within higher
education institutions as a whole is of utmost pertinence if a nation-s
human capital is to be nurtured to become change agents for the
preservation of environment. This paper discusses approaches that
can be adapted by institutions of higher learning to include
environmental literacy within the graduate-s higher learning
experience.