Abstract: This paper presents a method for obtaining the
desired reference current for Voltage Source Converter (VSC) of the Shunt Active Power Filter (SAPF) using Synchronous Reference Frame Theory. The method relies on the performance of the Proportional-Integral (PI) controller for
obtaining the best control performance of the SAPF. To
improve the performance of the PI controller, the feedback
path to the integral term is introduced to compensate the
winding up phenomenon due to integrator. Using Reference
Frame Transformation, reference signals are transformed from
a - b - c stationery frame to 0 - d - q rotating frame.
Using the PI controller, the reference signals in the 0 - d - q rotating frame are controlled to get the desired reference signals for the Pulse Width Modulation. The synchronizer, the Phase Locked Loop (PLL) with PI filter is used for
synchronization, with much emphasis on minimizing delays. The system performance is examined with Shunt Active Power Filter simulation model.
Abstract: As we make progressive products for good works, and
future industries want to get higher speed and resolution from various
developments in the robotics as well as precise control system, the
concept of control feedback is getting more important. Within a range
of industrial developments, the concept is most responsible for the
high reliability of a device. We explain an efficient analyzing method
of a rotary encoder such as an incremental type encoder and absolute
type encoder using the LabVIEW program
Abstract: Lateral-torsional buckling (LTB) is one of the
phenomenae controlling the ultimate bending strength of steel Ibeams
carrying distributed loads on top flange. Built-up I-sections
are used as main beams and distributors. This study investigates the
ultimate bending strength of such beams with sections of different
classes including slender elements. The nominal strengths of the
selected beams are calculated for different unsupported lengths
according to the Provisions of the American Institute of Steel
Constructions (AISC-LRFD). These calculations are compared with
results of a nonlinear inelastic study using accurate FE model for this
type of loading. The goal is to investigate the performance of the
provisions for the selected sections. Continuous distributed load at
the top flange of the beams was applied at the FE model.
Imperfections of different values are implemented to the FE model to
examine their effect on the LTB of beams at failure, and hence, their
effect on the ultimate strength of beams. The study also introduces a
procedure for evaluating the performance of the provisions compared
with the accurate FEA results of the selected sections. A simplified
design procedure is given and recommendations for future code
updates are made.
Abstract: The effect of flakes from biologically activated hullless barley grain and malt extract on microbiological safety of yoghurt was studied. Pasteurized milk, freeze-dried yoghurt culture YF-L811 (Chr. Hansen, Denmark), flakes from biologically activated hull-less barley grain (Latvia) and malt extract (Ilgezeem, Latvia) were used for experiments. Yoghurt samples with flakes from biologically activated hull-less barley grain and malt extract were analyzed for total plate count of mesophylic aerobic and facultative anaerobic microorganisms, as well yeasts and moulds population during shelflife. Results showed that the changes of pH and titratable acidity affected the concentration of added malt extract. The lowest pH and the highest titratable acidity were determined in samples YFBG5% ME4% and YFBG5% ME6% on the 14th day. The total plate count decreased in all yoghurt samples except sample YFBG5% ME6%, where was determined the increase of microorganisms from 7th till 14th day. The adding of flakes from biologically activated hull-less barley grain in yoghurt samples caused the higher initial content of yeasts and moulds comparing with control. The growth of yeasts and moulds during shelf-life provided the added malt extract in yoghurt samples. Yoghurt enriched with flakes from biologically activated hull-less barley grain and malt extract from a microbiological perspective is safe product.
Abstract: We present an integration approach of a CMOS biosensor into a polymer based microfluidic environment suitable for mass production. It consists of a wafer-level-package for the silicon die and laser bonding process promoted by an intermediate hot melt foil to attach the sensor package to the microfluidic chip, without the need for dispensing of glues or underfiller. A very good condition of the sensing area was obtained after introducing a protection layer during packaging. A microfluidic flow cell was fabricated and shown to withstand pressures up to Δp = 780 kPa without leakage. The employed biosensors were electrically characterized in a dry environment.
Abstract: Cabbage seedlings grown in vitro were exposed to
excess levels of heavy metals, including Cd, Mo, and Zn. High metal
levels affected plant growth at cotyledonary stage. Seedlings under
Cd, Mo, and Zn treatments could not produce root hairs and true
leaves. Under stress conditions, seedlings accumulated a higher
amount of anthocyanins in their cotyledons than those in the control.
The pigments isolated from Cd and Zn stressed seedling cotyledons
appeared as pink, while under Mo stress, was dark pink or purple.
Moreover, excess Mo stress increased antioxidant enzyme activities
of APX, CAT, SOD. These results suggest that, under excess Mo
stress, the induced antioxidant enzyme activity of cabbage seedlings
may function as a protective mechanism to shield the plants from
toxicity and exacerbated growth.
Abstract: Phytophthora cinnamomi (P. c) is a plant pathogenic
oomycete that is capable of damaging plants in commercial production
systems and natural ecosystems worldwide. The most common
methods for the detection and diagnosis of P. c infection are
expensive, elaborate and time consuming. This study was carried out
to examine whether species specific and life cycle specific volatile
organic compounds (VOCs) can be absorbed by solid-phase
microextraction fibers and detected by gas chromatography that are
produced by P. c and another oomycete Pythium dissotocum. A
headspace solid-phase microextraction (HS-SPME) together with gas
chromatography (GC) method was developed and optimized for the
identification of the VOCs released by P. c. The optimized parameters
included type of fiber, exposure time, desorption temperature and
desorption time. Optimization was achieved with the analytes of P.
c+V8A and V8A alone. To perform the HS-SPME, six types of fiber
were assayed and compared: 7μm Polydimethylsiloxane (PDMS),
100μm Polydimethylsiloxane (PDMS), 50/30μm
Divinylbenzene/CarboxenTM/Polydimethylsiloxane
DVB/CAR/PDMS), 65μm Polydimethylsiloxane/Divinylbenzene
(PDMS/DVB), 85μm Polyacrylate (PA) fibre and 85μm CarboxenTM/
Polydimethylsiloxane (Carboxen™/PDMS). In a comparison of the
efficacy of the fibers, the bipolar fiber DVB/CAR/PDMS had a higher
extraction efficiency than the other fibers. An exposure time of 16h
with DVB/CAR/PDMS fiber in the sample headspace was enough to
reach the maximum extraction efficiency. A desorption time of 3min
in the GC injector with the desorption temperature of 250°C was
enough for the fiber to desorb the compounds of interest. The chromatograms and morphology study confirmed that the VOCs from
P. c+V8A had distinct differences from V8A alone, as did different
life cycle stages of P. c and different taxa such as Pythium dissotocum.
The study proved that P. c has species and life cycle specific VOCs,
which in turn demonstrated the feasibility of this method as means of
Abstract: The study aimed to identify the logical structure of
data and particularities of developing and testing a website designed
for selling farm products through online auctions.
The research is based on a short literature review in the field and
exploratory trials of some successful models from other industries, in
order to identify the advantages of using such tool, as well as the
optimal structure and functionality of an auction portal. In the last
part, the study focuses on the results of testing the website by the
potential beneficiaries.
Conclusions of the study underlines that the particularities of some
agricultural products could raise difficulties in the process of selling
them through online auctions, but the use of such system it is
perceived to bring significant improvements in the supply chain.
The results of scientific investigations require a more detailed
study regarding the importance of using quality standards for
agricultural products sold via online auction, the impact that
implementation of an online payment system could have on trade
with agricultural products and problems which could arise in using
the website in different countries.
Abstract: The nutrient composition and sensory properties of
poultry-based patties (PBPs) incorporated with various levels of grey
oyster mushroom (Pleurotus sajor-caju, PSC) were studied. The
PBPs were formulated with either 0%, 25% or 50% of fresh ground
PSC. Results show poultry patty formulated with 25% PSC had
protein content of 17.46% lower than the control patty which had
18.13% but it was not significant. Meanwhile, both cooked poultry
patties containing 25% and 50% PSC significantly recorded lower
concentration of fat at 10.67% and 7.15%, respectively. On the other
hand, poultry patty added with 50% ground PSC shows the highest
concentration of total dietary fibre (TDF) of 4.90 g/100g compared to
poultry patty containing 25% of mushroom (3.40 g/100g) and to the
control (1.90g/100g). In addition, patty incorporated with 25% PSC
had moisture content of 57.91% which is significantly lower than
patty formulated with 50% which had moisture of 61.80%. In the
sensory evaluation, there were no differences recorded in all sensory
attributes of PSC-based patties judged by untrained panelists. In
conclusion, the addition of PSC to replace poultry meat can be
recommended for the purpose of lowering production cost, enhancing
nutritional composition and maintaining the acceptability of poultry
patties.
Abstract: This paper provides new ways to explore the old
problem of failure of information systems development in an
organisation. Based on the theory of cognitive dissonance,
information systems (IS) failure is defined as a gap between what the
users expect from an information system and how well these
expectations are met by the perceived performance of the delivered
system. Bridging the expectation-perception gap requires that IS
professionals make a radical change from being the proprietor of
information systems and products to being service providers. In order
to deliver systems and services that IS users perceive as valuable, IS
people must become expert in determining and assessing users-
expectations and perceptions. It is also suggested that the IS
community, in general, has given relatively little attention to the
front-end process of requirements specification for IS development.
There is a simplistic belief that requirements are obtainable from
users, they are then translatable into a formal specification. The
process of information needs analysis is problematic and worthy of
investigation.
Abstract: TTV is an unenveloped circular single-stranded DNA
virus with a diameter of 30-32 nm that first was described in 1997 in
Japan. TTV was detected in various populations without proven
pathology, including blood donors and in patients with chronic HBV
and HCV hepatitis. The aim of this study was to determine the
prevalence of TTV DNA in Iranian patients with chronic hepatitis B
and C. Viral TTV-DNA was studied in 442 samples (202 with HBV,
138 with HCV and 102 controls) collected from west south of Iran.
All extracted serum DNA was amplified by TTV ORF1 gene specific
primers using the semi nested PCR technique. TTV DNA was
detected in the serum of 8.9% and 10.8% patients with chronic
hepatitis B and C, respectively. Prevalence of TTV-DNA in the serum
of 102 controls was 2.9%. Results showed significant relation of TTV
with HBV and HCV in patients by using T test examination (P
Abstract: Fruit drying is a well known process mostly used for
preservation of fruits. Osmotic dehydration of apricot slices were
carried out in three different salt-sucrose concentrations and four
different temperatures. Also three different weight ratios of solution
to sample were conducted to one set of experiments. The dehydration
curves were constructed using Peleg-s model. Increasing the solution
volume increased the mass transfer rate and hence the solid gain
increased rapidly. Increasing the volume of osmotic media caused an
increase in overall mass transfer but a 'solution to sample' ratio of 5:1
gave the best product quality. The best temperature and concentration
that had a high water loss to solid gain ratio and an acceptable taste
were 40°C and 5%, respectively.
Abstract: In recent decade's tourism industry is one of main
reasons of the social and economical development for many
countries; so these countries try to gain more portion of it for
themselves. The excessive natural and cultural touristy potentialities
in Iran made this country to be one of the most attractive sightseeing
areas, although; Iran has got the lowest rate of tourists. Khark Island
is about 32 km. It is a beautiful coral reef coast; about 98% of oil
export has been done through this place. The ecotourism
potentialities of Khark and Kharko Islands (about 3.7km far from
Khark) are the reason to consider ecotourism and the main activity in
these islands which is exporting oil at the same time. This article
refers to way of measuring the geographical coordination of the
place, and the potentialities, ecotourism attraction of the islands and
introduces some ideas in order to expand tourism in the islands.
Abstract: Higher capacities of power plants together with
increased awareness on environmental considerations have led to
taller height of stacks. It is seen that strong wind can result in falling
of stacks. So, aerodynamic consideration of stacks is very important
in order to save the falling of stacks. One stack is not enough in
industries and power sectors and two or three stacks are required for
proper operation of the unit. It is very important to arrange the stacks
in proper way to resist their downfall. The present experimental
study concentrates on the mutual effect of three nearby stacks on
each other at three different arrangements, viz. linear, side-by-side
and triangular. The experiments find out the directions of resultant
forces acting on the stacks in different configurations so that proper
arrangement of supports can be made with respect to the wind
directionality obtained from local meteorological data. One can also
easily ascertain which stack is more vulnerable to wind in
comparison to the others for a particular configuration. Thus, this
study is important in studying the effect of wind force on three stacks
in different arrangements and is very helpful in placing the supports
in proper places in order to avoid failing of stack-like structures due
to wind.
Abstract: In our modern society electricity is vital to our health,
safety, comfort and well-being. While our daily use of electricity is
often taken for granted, public concern has arisen about potential
adverse health effects from electric and magnetic – electromagnetic –
fields (EMFs) produced by our use of electricity.
This paper aims to compare between the measured magnetic field
values and the simulated models for the indoor medium to low
voltage (MV/LV) distribution substations.
To calculate the magnetic flux density in the substations,
interactive software SUBCALC is used which is based on closed
form solution of the Biot-Savart law with 3D conductor model.
The comparison between the measured values and the simulated
models was acceptable. However there were some discrepancies, as
expected, may be due to the current variation during measurements.
Abstract: The issue of classifying objects into one of predefined
groups when the measured variables are mixed with different types
of variables has been part of interest among statisticians in many
years. Some methods for dealing with such situation have been
introduced that include parametric, semi-parametric and nonparametric
approaches. This paper attempts to discuss on a problem
in classifying a data when the number of measured mixed variables is
larger than the size of the sample. A propose idea that integrates a
dimensionality reduction technique via principal component analysis
and a discriminant function based on the location model is discussed.
The study aims in offering practitioners another potential tool in a
classification problem that is possible to be considered when the
observed variables are mixed and too large.
Abstract: Calcium magnesium acetate (CMA) is environmentally
benign deicing chemicals that can replace sodium chloride that is
widely used on roads and highways at present for snow and ice control
to provide safe driving conditions during winter. The price of CMA
from petroleum-derived acetic acid is quite expensive. The bamboo
vinegar is the by-product from bamboo charcoal production. The
bamboo vinegar was used to prepare calcium acetate as raw materials,
and its deicing and corrosive performances were studied in this paper.
The results show that the freezing temperature of calcium acetate is
lower than that of sodium chloride when they have same molar
concentration, the deicing performance of calcium acetate is better
than that of sodium chloride when they have same moles, while the
deicing performance of sodium chloride is better than that of calcium
acetate. The corrosion of sodium chloride on iron-nail and steel-nail is
larger than that of calcium acetate whether they have same mass
concentration or same molar concentration, and the corrosion of
sodium chloride and calcium acetate on iron-nail is larger than that on
steel-nail, and calcium acetate almost hasn't corrosion on steel-nail.
Abstract: Work ethic and labour productivity issues are
extremely important for any society. It has been long proven by the
global practice and various scholars that the country promoting the
labour has always been way forward from the other countries. This
paper studies the thoughts suggested by M.Weber, Confucius, Lee
Kuan Yew, Mahathir Mohammad and other prominent thinkers
concerning the issues of work ethics and labour productivity. The
article analyzes why developed nations are way more advanced in
their development compared to other nations.
Abstract: Production of hard-to-cut materials with uncoated carbide cutting tools in turning, not only cause tool life reduction but also, impairs the product surface roughness. In this paper, influence of hot machining method were studied and presented in two cases. Case1-Workpiece surface roughness quality with constant cutting parameter and 300 ºC initial workpiece surface temperature. Case 2- Tool temperature variation when cutting with two speeds 78.5 (m/min) and 51 (m/min). The workpiece material and tool used in this study were AISI 1060 steel (45HRC) and uncoated carbide TNNM 120408-SP10(SANDVIK Coromant) respectively. A gas flam heating source was used to preheating of the workpiece surface up to 300 ºC, causing reduction of yield stress about 15%. Results obtained experimentally, show that the method used can considerably improved surface quality of the workpiece.
Abstract: The internet is constantly expanding. Identifying web
links of interest from web browsers requires users to visit each of the
links listed, individually until a satisfactory link is found, therefore
those users need to evaluate a considerable amount of links before
finding their link of interest; this can be tedious and even
unproductive. By incorporating web assistance, web users could be
benefited from reduced time searching on relevant websites. In this
paper, a rough set approach is presented, which facilitates
classification of unlimited available e-vocabulary, to assist web users
in reducing search times looking for relevant web sites. This
approach includes two methods for identifying relevance data on web
links based on the priority and percentage of relevance. As a result of
these methods, a list of web sites is generated in priority sequence
with an emphasis of the search criteria.