Abstract: Analytical formula for the optical gain based on a
simple parabolic-band by introducing theoretical expressions for the
quantized energy is presented. The model used in this treatment take
into account the effects of intraband relaxation. It is shown, as a
result, that the gain for the TE mode is larger than that for TM mode
and the presence of acceptor impurity increase the peak gain.
Abstract: An industrial system for the production of white
liquor of a paper industry, Klabin Paraná Papéis, formed by ten
reactors was modeled, simulated, and analyzed. The developed model
considered possible water losses by evaporation and reaction, in
addition to variations in volumetric flow of lime mud across the
reactors due to composition variations. The model predictions agreed
well with the process measurements at the plant and the results
showed that the slaking reaction is nearly complete at the third
causticizing reactor, while causticizing ends by the seventh reactor.
Water loss due to slaking reaction and evaporation occurs more
pronouncedly in the slaking reaction than in the final causticizing
reactors; nevertheless, the lime mud flow remains nearly constant
across the reactors.
Abstract: Measuring the Electrocardiogram (ECG) signal is an
essential process for the diagnosis of the heart diseases. The ECG
signal has the information of the degree of how much the heart
performs its functions. In medical diagnosis and treatment systems,
Decision Support Systems processing the ECG signal are being
developed for the use of clinicians while medical examination. In this
study, a modular wireless ECG (WECG) measuring and recording
system using a single board computer and e-Health sensor platform
is developed. In this designed modular system, after the ECG signal
is taken from the body surface by the electrodes first, it is filtered and
converted to digital form. Then, it is recorded to the health database
using Wi-Fi communication technology. The real time access of the
ECG data is provided through the internet utilizing the developed
web interface.
Abstract: Milk is considered as an essential and complete food.
The present study was conducted at Milk Plant Mohali especially in
reference to the procurement section where the cash inflow was
maximum, with the objective to achieve higher productivity and
reduce wastage of milk. In milk plant it was observed that during the
month of Jan-2014 to March-2014 the average procurement of milk
was Rs. 4, 19, 361 liter per month and cost of procurement of milk is
Rs 35/- per liter. The total cost of procurement thereby equal to Rs.
1crore 46 lakh per month, but there was mismatch in procurementproduction
of milk, which leads to an average loss of Rs. 12, 94, 405
per month. To solve the procurement-production problem Quality
Control Tools like brainstorming, Flow Chart, Cause effect diagram
and Pareto analysis are applied wherever applicable. With the
successful implementation of Quality Control tools an average saving
of Rs. 4, 59, 445 per month is done.
Abstract: As per the statistical data, the Doubly-fed Induction
Generator (DFIG) based wind turbine with variable speed and
variable pitch control is the most common wind turbine in the
growing wind market. This machine is usually used on the grid
connected wind energy conversion system to satisfy grid code
requirements such as grid stability, Fault Ride Through (FRT), power
quality improvement, grid synchronization and power control etc.
Though the requirements are not fulfilled directly by the machine, the
control strategy is used in both the stator as well as rotor side along
with power electronic converters to fulfil the requirements stated
above. To satisfy the grid code requirements of wind turbine, usually
grid side converter is playing a major role. So in order to improve the
operation capacity of wind turbine under critical situation, the
intensive study of both machine side converter control and grid side
converter control is necessary In this paper DFIG is modeled using
power components as variables and the performance of the DFIG
system is analysed under grid voltage fluctuations. The voltage
fluctuations are made by lowering and raising the voltage values in
the utility grid intentionally for the purpose of simulation keeping in
view of different grid disturbances.
Abstract: It is the patient compliance and stability in
combination with controlled drug delivery and biocompatibility that
forms the core feature in present research and development of
sustained biodegradable patch formulation intended for wound
healing. The aim was to impart sustained degradation, sterile
formulation, significant folding endurance, elasticity,
biodegradability, bio-acceptability and strength. The optimized
formulation comprised of polymers including Hydroxypropyl methyl
cellulose, Ethylcellulose, and Gelatin, and Citric Acid PEG Citric
acid (CPEGC) triblock dendrimers and active Curcumin. Polymeric
mixture dissolved in geometric order in suitable medium through
continuous stirring under ambient conditions. With continued stirring
Curcumin was added with aid of DCM and Methanol in optimized
ratio to get homogenous dispersion. The dispersion was sonicated
with optimum frequency and for given time and later casted to form a
patch form. All steps were carried out under strict aseptic conditions.
The formulations obtained in the acceptable working range were
decided based on thickness, uniformity of drug content, smooth
texture and flexibility and brittleness. The patch kept on stability
using butter paper in sterile pack displayed folding endurance in
range of 20 to 23 times without any evidence of crack in an
optimized formulation at room temperature (RT) (24 ± 2°C). The
patch displayed acceptable parameters after stability study conducted
in refrigerated conditions (8±0.2°C) and at RT (24 ± 2°C) up to 90
days. Further, no significant changes were observed in critical
parameters such as elasticity, biodegradability, drug release and drug
content during stability study conducted at RT 24±2°C for 45 and 90
days. The drug content was in range 95 to 102%, moisture content
didn’t exceeded 19.2% and patch passed the content uniformity test.
Percentage cumulative drug release was found to be 80% in 12h and
matched the biodegradation rate as drug release with correlation
factor R2>0.9. The biodegradable patch based formulation developed
shows promising results in terms of stability and release profiles.
Abstract: In recent years, the use of the aluminum based alloys
in the industry and technology are increasing. Alloying elements in
aluminum have further been improving the strength and stiffness
properties that provide superior compared to other metals. In this
study, investigation of physical properties (microstructure,
microhardness, tensile strength, electrical conductivity and thermal
properties) in the Al-12.6wt.%Si-%2wt.Ni ternary alloy were
investigated. Al-Si-Ni alloy was prepared in vacuum atmosphere. The
samples were directionally solidified upwards with different growth
rate V (8.3−165.45 μm/s) at constant temperature gradient G (7.73
K/mm). The flake spacings (λ), microhardness (HV), ultimate tensile
strength (σ), electrical resistivity (ρ) and thermal properties (H, Cp,
Tm) of the samples were measured. Influence of the growth rate and
spacings on microhardness, ultimate tensile strength and electrical
resistivity were investigated and relationships between them were
obtained. According to results, λ values decrease with increasing V,
but HV, σ and ρ values increase with increasing V. Variations of
electrical resistivity (ρ) of solidified samples were also measured.
The enthalpy of fusion (H) and specific heat (Cp) for the alloy was
also determined by differential scanning calorimeter (DSC) from
heating trace during the transformation from liquid to solid. The
results in this work were compared with the previous similar
experimental results.
Abstract: In insulation and cooling of power transformers
various liquids are used. Mineral oils have wide availability and low
cost. However, they have a poor biodegradability potential and lower
fire point in comparison with other insulating liquids. Use of a liquid
having high biodegradability is important due to environmental
consideration. This paper investigates edible corn oil as an alternative
to mineral oil. Various properties of mineral and corn oil like
breakdown voltage, dissipation factor, relative dielectric constant,
power loss and resistivity were measured according to different
standards.
Abstract: Based on application requirements, nodes are static or
mobile in Wireless Sensor Networks (WSNs). Mobility poses
challenges in protocol design, especially at the link layer requiring
mobility adaptation algorithms to localize mobile nodes and predict
link quality to be established with them. This study implements
XMAC and Berkeley Media Access Control (BMAC) routing
protocols to evaluate performance under WSN’s static and mobility
conditions. This paper gives a comparative study of mobility-aware
MAC protocols. Routing protocol performance, based on Average
End to End Delay, Average Packet Delivery Ratio, Average Number
of hops, and Jitter is evaluated.
Abstract: This paper examines the relationship between
corporate governance rating and stock prices of 26 Turkish firms
listed in Turkish stock exchange (Borsa Istanbul) by using panel data
analysis over five-year period. The paper also investigates the stock
performance of firms with governance rating with regards to the
market portfolio (i.e. BIST 100 Index) both prior and after
governance scoring began. The empirical results show that there is no
relation between corporate governance rating and stock prices when
using panel data for annual variation in both rating score and stock
prices. Further analysis indicates surprising results that while the
selected firms outperform the market significantly prior to rating, the
same performance does not continue afterwards.
Abstract: While choosing insulating oil, characteristic features
such as thermal cooling, endurance, efficiency and being
environment-friendly should be considered. Mineral oils are referred
as petroleum-based oil. In this study, vegetable oils investigated as an
alternative insulating liquid to mineral oil. Dissipation factor,
breakdown voltage, relative dielectric constant and resistivity
changes with the frequency and voltage of mineral, rapeseed and nut
oils were measured. Experimental studies were performed according
to ASTM D924 and IEC 60156 standards.
Abstract: Mitigating soil erosion, especially in Mediterranean
countries such as Greece, is essential in order to maintain
environmental and agricultural sustainability. In this paper, scientific
publications related to soil erosion studies in Greece were reviewed
and categorized. To accomplish this, the online search engine of
Scopus was used. The key words were “soil”, “erosion” and
“Greece.” An analysis of the published articles was conducted at
three levels: i) type of publication, ii) chronologic and iii) thematic. A
hundred and ten publications published in scientific journals were
reviewed. The results showed that the awareness regarding the soil
erosion in Greece has increased only in the last decades. The
publications covered a wide range of thematic categories such as the
type of studied areas, the physical phenomena that trigger and
influence the soil erosion, the negative anthropogenic impacts on
them, the assessment tools that were used in order to examine the
threat and the proper management. The analysis of these articles was
significant and necessary in order to find the scientific gaps of soil
erosion studies in Greece and help enhance the sustainability of soil
management in the future.
Abstract: Perception, evaluation and representation of the
environment have been the subject of many disciplines including
psychology, geography and architecture. In environmental and social
psychology literature there are several evidences which suggest that
cognitive representations about a place consisted of not only
geographic items but also social and cultural. Mental representations
of residence area or a country are influenced and determined by
social-demographics, the physical and social context. Thus, all
mental representations of a given place are also social
representations. Cognitive maps are the main and common
instruments that are used to identify spatial images and the difference
between physical and subjective environments. The aim of the
current study is investigating the mental and social representations of
Turkey in university students’ minds. Data was collected from 249
university students from different departments (i.e. psychology,
geography, history, tourism departments) of Ege University.
Participants were requested to reflect Turkey in their mind onto the
paper drawing sketch maps. According to the results, cognitive maps
showed geographic aspects of Turkey as well as the context of
symbolic, cultural and political reality of Turkey. That is to say, these
maps had many symbolic and verbal items related to critics on social
and cultural problems, ongoing ethnic and political conflicts, and
actual political agenda of Turkey. Additionally, one of main
differentiations in these representations appeared in terms of the East
and West side of the Turkey, and the representations of the East and
West was varied correspondingly participants’ cultural background,
their ethnic values, and where they have born. The results of the
study were discussed in environmental and social psychological
perspective considering cultural and social values of Turkey and
current political circumstances of the country.
Abstract: Aim of this research study is to investigate and
establish the characteristics of brain dominances (BD) and multiple
intelligences (MI). This experimentation has been conducted for the
sample size of 552 undergraduate computer-engineering students. In
addition, mathematical formulation has been established to exhibit
the relation between thinking and intelligence, and its correlation has
been analyzed. Correlation analysis has been statistically measured
using Pearson’s coefficient. Analysis of the results proves that there
is a strong relational existence between thinking and intelligence.
This research is carried to improve the didactic methods in
engineering learning and also to improve e-learning strategies.
Abstract: Reticence is a prominent and complex phenomenon
which occurs in foreign language classrooms and influences students’
oral passivity. The present study investigated the extent in which
students experience reticence in the EFL classrooms and explored the
underlying factors triggering reticence. The participants were 104
Iranian freshmen undergraduate male and female EFL students, who
enrolled in listening and speaking courses, all majoring in English
studying at Islamic Azad University Isfahan (Khorasgan) Branch and
University of Isfahan, Isfahan, Iran. To collect the data, the Reticence
Scale-12 (RS-12) questionnaire which measures the level of reticence
consisting of six dimensions (anxiety, knowledge, timing,
organization, skills, and memory) was administered to the
participants. The statistical analyses showed that the reticent level
was high among the Iranian EFL undergraduate students, and their
major problems were feelings of anxiety and delivery skills.
Moreover, the results revealed that factors such as low English
proficiency, the teaching method, and lack of confidence contributed
to the students’ reticence in Iranian EFL classrooms. It can be
implied that language teachers’ awareness of learners’ reticence can
help them choose more appropriate activities and provide a friendly
environment enhancing hopefully more effective participation of EFL
learners. The findings can have implications for EFL teachers,
learners and policy makers.
Abstract: Students' academic achievement, along with the
effects of different variables, has been a serious concern of educators
since long ago. This study was an attempt to investigate the interplay
of Locus of Control (LOC), academic achievement and biological
variables among Iranian online EFL Learners. The participants of the
study included 100 students of different age groups and genders
studying English online at Iran Language Institute (ILI), Isfahan,
Iran. The instrument used was Trice Academic LOC questionnaire
which identifies orientations of internality or externality. The
participants' Grade Point Averages (GPAs) were used as the measure
of their academic achievement. A series of independent samples ttests
were performed on the data. The results of the study showed that
(a) there were no significant differences between male and female
participants in LOC orientation, (b) there was no relationship
between LOC and academic achievement among internal males and
females, (c) external females were better achievers than external
males, (d) and the age had no significant relationship with LOC and
academic achievement. It can be concluded that the social, cultural
patterns of genders have changed. This study might help sociologists
and psychologists as well as applied linguists in that they reflect the
recent social changes and their effects on the LOC and their
consequent implications in teaching languages.
Abstract: A novel design technique employing CMOS Current
Feedback Operational Amplifier (CFOA) is presented. The feature of
consumption very low power in designing pseudo-OTA is used to
decreasing the total power consumption of the proposed CFOA. This
design approach applies pseudo-OTA as input stage cascaded with
buffer stage. Moreover, the DC input offset voltage and harmonic
distortion (HD) of the proposed CFOA are very low values compared
with the conventional CMOS CFOA due to the symmetrical input
stage. P-Spice simulation results are obtained using 0.18μm MIETEC
CMOS process parameters and supply voltage of ±1.2V, 50μA
biasing current. The p-spice simulation shows excellent improvement
of the proposed CFOA over existing CMOS CFOA. Some of these
performance parameters, for example, are DC gain of 62. dB, openloop
gain bandwidth product of 108 MHz, slew rate (SR+) of
+71.2V/μS, THD of -63dB and DC consumption power (PC) of
2mW.
Abstract: Any variation in environmental characteristics of
geomorphosites would lead to destabilisation of their geotouristic
values all around the planet. The Urmia lake, with an area of
approximately 5,500 km2 and a catchment area of 51,876 km2, and to
which various reasons over time, especially in the last fifty years
have seen a sharp decline and have decreased by about 93 % in two
recent decades. These variations are not only driving significant
changes in the morphology and ecology of the present lake
landscape, but at the same time are shaping newly formed
morphologies, which vanished some valuable geomorphosites or
develop into smaller geomorphosites with significant value from a
scientific and cultural point of view. This paper analyses and
discusses features and evolution in several representative coastal and
island geomorphosites. For this purpose, a total of 23 geomorphosites
were studied in two data series (1963 and 2015) and the respective
data were compared and analysed. The results showed, the total loss
in geomorphosites area in a half century amounted to a loss of more
than 90% of the valuable geomorphosites. Moreover, the comparison
between the mean yearly value of coastal area lost over the entire
period and the yearly average calculated for the shorter period (1998-
2014) clearly indicates a pattern of acceleration. This acceleration in
the rate of reduction in lake area was seen in most of the southern
half of the lake. In the region as well, the general water-level falling
is not only causing the loss of a significant water resource, which is
followed by major impact on regional ecosystems, but is also driving
the most marked recent (last century) changes in the geotouristic
landscapes. In fact, the disappearance of geomorphosites means the
loss of tourism phenomenon. In this context attention must be paid to
the question of conservation. The action needed to safeguard
geomorphosites includes: 1) Preventive action, 2) Corrective action,
and 3) Sharing knowledge.
Abstract: The posterior reference for the ala tragal line is a
cause of confusion, with different authors suggesting different
locations as to the superior, middle or inferior part of the tragus. This
study was conducted on 200 subjects to evaluate if any correlation
exists between the variation of angulation of palatal throat form and
the relative parallelism of occlusal plane to ala-tragal line at different
tragal levels. A custom made Occlusal Plane Analyzer was used to
check the parallelism between the ala-tragal line and occlusal plane.
A lateral cephalogram was shot for each subject to measure the
angulation of the palatal throat form. Fisher’s exact test was used to
evaluate the correlation between the angulation of the palatal throat
form and the relative parallelism of occlusal plane to the ala tragal
line. Also, a classification was formulated for the palatal throat form,
based on confidence interval. From the results of the study, the
inferior part, middle part and superior part of the tragus were seen as
the reference points in 49.5%, 32% and 18.5% of the subjects
respectively. Class I palatal throat form (41degree-50 degree), Class
II palatal throat form (below 41 degree) and Class III palatal throat
form (above 50 degree) were seen in 42%, 43% and 15% of the
subjects respectively. It was also concluded that there is no
significant correlation between the variation in the angulations of the
palatal throat form and the relative parallelism of occlusal plane to
the ala-tragal line.
Abstract: Due to the increasing efforts on saving our natural
environment a change in the structure of energy resources can be
observed - an increasing fraction of a renewable energy sources.
In many countries traditional underground coal mining loses its
significance but there are still countries, like Poland or Germany, in
which the coal based technologies have the greatest fraction in a total
energy production. This necessitates to make an effort to limit the
costs and negative effects of underground coal mining. The longwall
complex is as essential part of the underground coal mining. The
safety and the effectiveness of the work is strongly dependent of the
diagnostic state of powered roof supports.
The building of a useful and reliable diagnostic system requires
a lot of data. As the acquisition of a data of any possible operating
conditions it is important to have a possibility to generate a demanded
artificial working characteristics. In this paper a new approach of
modelling a leg pressure in the single unit of powered roof support.
The model is a result of the analysis of a typical working cycles.