Abstract: Ceramic obtained on the base of aluminum oxide has
wide application range, because it has unique properties, for example,
wear-resistance, dielectric characteristics, and exploitation ability at
high temperatures and in corrosive atmosphere. Low temperature
synthesis of α-Al2O3 is energo-economical process and it is topical
for developing technologies of corundum ceramics fabrication. In the present work possibilities of low temperature transformation
of oxyhydroxides in α-Al2O3, during the presence of small amount of
rare–earth elements compounds (also Th, Re), have been discussed.
Aluminum unstable oxyhydroxides have been obtained by hydrolysis
of aluminium isopropoxide, nitrates, sulphate, and chloride in
alkaline environment at 80-90ºC temperatures. β-Al(OH)3 has been
received from aluminum powder by ultrasonic development. Drying
of oxyhydroxide sol has been conducted with presence of various
types seeds, which amount reaches 0,1-0,2% (mas). Neodymium,
holmium, thorium, lanthanum, cerium, gadolinium, disprosium
nitrates and rhenium carbonyls have been used as seeds and they
have been added to the sol specimens in amount of 0.1-0.2% (mas)
calculated on metals. Annealing of obtained gels is carried out at 70–
1100ºC for 2 hrs. The same specimen transforms in α-Al2O3 at
1100ºC. At this temperature in case of presence of lanthanum and
gadolinium transformation takes place by 70-85%. In case of
presence of thorium stabilization of γ-and θ-phases takes place. It is
established, that thorium causes inhibition of α-phase generation at
1100ºC, and at the time when in all other doped specimens α-phase is
generated at lower temperatures (1000-1050ºC). Synthesis of various
type compounds and simultaneous consolidation has developed in the
furnace of OXY-GON. Composite materials containing oxide and
non-oxide components close to theoretical data have been obtained in
this furnace respectively. During the work the following devices have
been used: X-ray diffractometer DRON-3M (Cu-Kα, Ni filter,
2º/min), High temperature vacuum furnace OXY-GON, electronic
scanning microscopes Nikon ECLIPSE LV 150, NMM-800TRF,
planetary mill Pulverisette 7 premium line, SHIMADZU Dynamic
Ultra Micro Hardness Tester, DUH-211S, Analysette 12 Dyna sizer.
Abstract: An experimental study with four different types of bed
conditions was carried out to understand the effect of roughness in
open channel flow at two different Reynolds numbers. The bed
conditions include a smooth surface and three different roughness
conditions, which were generated using sand grains with a median
diameter of 2.46 mm. The three rough conditions include a surface
with distributed roughness, a surface with continuously distributed
roughness and a sand bed with a permeable interface. A commercial
two-component fibre-optic LDA system was used to conduct the
velocity measurements. The variables of interest include the mean
velocity, turbulence intensity, correlation between the streamwise and
the wall normal turbulence, Reynolds shear stress and velocity triple
products. Quadrant decomposition was used to extract the magnitude
of the Reynolds shear stress of the turbulent bursting events. The
effect of roughness was evident throughout the flow depth. The
results show that distributed roughness has the greatest roughness
effect followed by the sand bed and the continuous roughness.
Compared to the smooth bed, the streamwise turbulence intensity
reduces but the vertical turbulence intensity increases at a location
very close to the bed due to the introduction of roughness. Although
the same sand grain is used to create the three different rough bed
conditions, the difference in the turbulence intensity is an indication
that the specific geometry of the roughness has an influence on
turbulence structure.
Abstract: Mineral oil is commonly used for high voltage
transformer insulation. The insulation quality of mineral oil is
affecting the operation process of high voltage transformer. There are
many contaminations which could decrease the insulation quality of
mineral oil. One of them is water. This research talks about the effect
of water content on dielectric properties, physic properties, and
partial discharge pattern on mineral oil. Samples were varied with 10
varieties of water content value. And then all samples would be tested
to measure the dielectric properties, physic properties, and partial
discharge pattern. The result of this research showed that an
increment of water content value would decrease the insulation
quality of mineral oil.
Abstract: An analytical 4-DOF nonlinear model of a de Laval
rotor-stator system based on Energy Principles has been used
theoretically and experimentally to investigate fault symptoms in a
rotating system. The faults, namely rotor-stator-rub, crack and
unbalance are modeled as excitations on the rotor shaft. Mayes
steering function is used to simulate the breathing behaviour of the
crack. The fault analysis technique is based on waveform signal,
orbits and Fast Fourier Transform (FFT) derived from simulated and
real measured signals. Simulated and experimental results manifest
considerable mutual resemblance of elliptic-shaped orbits and FFT
for a same range of test data.
Abstract: Si-Ge solid solutions (bulk poly- and mono-crystalline
samples, thin films) are characterized by high perspectives for
application in semiconductor devices, in particular, optoelectronics
and microelectronics. From this point of view, complex studying of
structural state of the defects and structural-sensitive physical
properties of Si-Ge solid solutions depending on the contents of Si
and Ge components is very important. Present work deals with the
investigations of microstructure, microhardness, internal friction and
shear modulus of Si1-xGex(x≤0,02) bulk monocrystals conducted at
room temperature. Si-Ge bulk crystals were obtained by Czochralski
method in [111] crystallographic direction. Investigated
monocrystalline Si-Ge samples are characterized by p-type
conductivity and carriers’ concentration 5.1014-1.1015cm-3.
Microhardness was studied on Dynamic Ultra Micro hardness Tester
DUH-201S with Berkovich indenter. Investigate samples are characterized with 0,5x0,5x(10-15)mm3
sizes, oriented along [111] direction at torsion oscillations ≈1Hz,
multistage changing of internal friction and shear modulus has been
revealed in an interval of strain amplitude of 10-5-5.10-3. Critical
values of strain amplitude have been determined at which hysteretic
changes of inelastic characteristics and microplasticity are observed. The critical strain amplitude and elasticity limit values are also
determined. Dynamic mechanical characteristics decreasing trend is
shown with increasing Ge content in Si-Ge solid solutions. Observed
changes are discussed from the point of view of interaction of various
dislocations with point defects and their complexes in a real structure
of Si-Ge solid solutions.
Abstract: The effect of molybdate addition to chloride
environment on resistance of AISI 316Ti stainless steel to pitting
corrosion was studied. Potentiodynamic polarisation tests were
performed in 1 M and 0.1 M chloride acidified solutions with various
additions of sodium molybdate at room temperature. The presented
results compare the effect of molybdate anions on quality of passive
film (expressed by the pitting potential) in both chloride solutions.
The pitting potential increases with the increase inhibitor
concentration. The inhibitive effect of molybdate ions is stronger in
chloride solution of lower aggressiveness (0.1M).
Abstract: New and more powerful communications technologies
continue to emerge at a rapid pace and their uses in education are
widespread and the impact remarkable in the developing societies.
This study investigates Mobile Collaboration Learning Technique
(MCLT) on learners’ outcome among students in tertiary institutions
of developing nations (a case of Nigeria students). It examines the
significance of retention achievement scores of students taught using
mobile collaboration and conventional method. The sample consisted
of 120 students using Stratified random sampling method. Five
research questions and hypotheses were formulated, and tested at
0.05 level of significance. A student achievement test (SAT) was
made of 40 items of multiple-choice objective type, developed and
validated for data collection by professionals. The SAT was
administered to students as pre-test and post-test. The data were
analyzed using t-test statistic to test the hypotheses. The result
indicated that students taught using MCLT performed significantly
better than their counterparts using the conventional method of
instruction. Also, there was no significant difference in the post-test
performance scores of male and female students taught using MCLT.
Based on the findings, the following submissions was made that:
Mobile collaboration system be encouraged in the institutions to
boost knowledge sharing among learners, workshop and training
should be organized to train teachers on the use of this technique,
schools and government should consistently align curriculum
standard to trends of technological dictates and formulate policies
and procedures towards responsible use of MCLT.
Abstract: The McEliece cryptosystem is an asymmetric type of
cryptography based on error correction code. The classical McEliece
used irreducible binary Goppa code which considered unbreakable
until now especially with parameter [1024, 524, and 101], but it is
suffering from large public key matrix which leads to be difficult to
be used practically. In this work Irreducible and Separable Goppa
codes have been introduced. The Irreducible and Separable Goppa
codes used are with flexible parameters and dynamic error vectors. A
Comparison between Separable and Irreducible Goppa code in
McEliece Cryptosystem has been done. For encryption stage, to get
better result for comparison, two types of testing have been chosen;
in the first one the random message is constant while the parameters
of Goppa code have been changed. But for the second test, the
parameters of Goppa code are constant (m=8 and t=10) while the
random message have been changed. The results show that the time
needed to calculate parity check matrix in separable are higher than
the one for irreducible McEliece cryptosystem, which is considered
expected results due to calculate extra parity check matrix in
decryption process for g2(z) in separable type, and the time needed to
execute error locator in decryption stage in separable type is better
than the time needed to calculate it in irreducible type. The proposed
implementation has been done by Visual studio C#.
Abstract: In this work, we attempt to associate firm
characteristics with innovative activity. We collect microdata from
listed firms of selected Eurozone Country-members, after the
beginning of 2007 financial crisis. The following literature, several
indicators of growth and performance were selected and tested for
their ability to interpret innovative activity. The main scope is to
examine the possible differences in performance and growth between
innovative and non-innovative firms, during a severe recession.
Additionally to that, a special focus will be held on whether
macroeconomic performance and national innovation system,
determines the extent of innovators' performance. Preliminary
findings, through correlation matrices and non-parametric tests,
strongly indicate the positive relation between innovative activity and
most of the measures used (profitability, size, employment),
confirming that even during a recessionary period, innovative firms
not only survive but also seem to succeed better economic results in
almost all indexes relative to non-innovative. However, even though
innovators seem to perform better in all economies examined, the
extent of that performance seems to be strongly affected by the
supportive mechanisms (financial and structural) that their country
provides. Thus, it is clear, that the technologically intensive 'gap'
between European South and North, during the economic crisis,
became chaotic, due to the harsh austerity measures and reduced
budgets in those countries, even in sectors with high potentials in
economic activity and employment, impairing the effects of crisis and
enhancing the vicious circle of recession.
Abstract: Predicting earnings management is vital for the capital
market participants, financial analysts and managers. The aim of this
research is attempting to respond to this query: Is there a significant
difference between the regression model and neural networks’
models in predicting earnings management, and which one leads to a
superior prediction of it? In approaching this question, a Linear
Regression (LR) model was compared with two neural networks
including Multi-Layer Perceptron (MLP), and Generalized
Regression Neural Network (GRNN). The population of this study
includes 94 listed companies in Tehran Stock Exchange (TSE)
market from 2003 to 2011. After the results of all models were
acquired, ANOVA was exerted to test the hypotheses. In general, the
summary of statistical results showed that the precision of GRNN did
not exhibit a significant difference in comparison with MLP. In
addition, the mean square error of the MLP and GRNN showed a
significant difference with the multi variable LR model. These
findings support the notion of nonlinear behavior of the earnings
management. Therefore, it is more appropriate for capital market
participants to analyze earnings management based upon neural
networks techniques, and not to adopt linear regression models.
Abstract: This paper proposes a novel heuristic algorithm that aims to determine the best size and location of distributed generators in unbalanced distribution networks. The proposed heuristic algorithm can deal with the planning cases where power loss is to be optimized without violating the system practical constraints. The distributed generation units in the proposed algorithm is modeled as voltage controlled node with the flexibility to be converted to constant power factor node in case of reactive power limit violation. The proposed algorithm is implemented in MATLAB and tested on the IEEE 37 -node feeder. The results obtained show the effectiveness of the proposed algorithm.
Abstract: The latest years the number of immigrants at Greece
has increased dramatically. Their impact on the National Health
System (NHS) has not been yet thoroughly investigated. This paper
analyses the cost of immigrants to the NHS hospitals of the region of
Eastern Macedonia and Thrace. The data are collected from 2005 to
2011 from five different hospitals and are analysed using linear
mixed effects models in order to investigate the effects of nationality
and year on the cost of hospitalization and treatment. The results
show that generally the Greek nationality patients have a higher mean
cost of hospitalization compared to the immigrants and that there is
an increasing trend for the cost except for the year 2010.
Abstract: The paper aims to evaluate the effect of online
advertising on consumer purchase behavior in Malaysian
organizations. The paper has potential to extend and refine theory. A
survey was distributed among Students of UTM university during the
winter 2014 and 160 responses were collected. Regression analysis
was used to test the hypothesized relationships of the model. Result
shows that the predictors (cost saving factor, convenience factor and
customized product or services) have positive impact on intention to
continue seeking online advertising.
Abstract: This paper reports the viability of developing Zn-27Al
alloy matrix hybrid composites reinforced with alumina, graphite and
fly ash (solid waste bye product of coal in thermal power plants).
This research work was aimed at developing low cost-high
performance Zn-27Al matrix composite with low density. Alumina
particulates (Al2O3), graphite added with 0, 2, 3, 4 and 5 wt% fly ash
were utilized to prepare 10wt% reinforcing phase with Zn-27Al alloy
as matrix using two-step stir casting method. Density measurement,
estimated percentage porosity, tensile testing, micro hardness
measurement and optical microscopy were used to assess the
performance of the composites produced. The results show that the
hardness, ultimate tensile strength, and percent elongation of the
hybrid composites decrease with increase in fly ash content. The
maximum decrease in hardness and ultimate tensile strength of
13.72% and 15.25% respectively were observed for composite grade
containing 5wt% fly ash. The percentage elongation of composite
sample without fly ash is 8.9% which is comparable with that of the
sample containing 2wt% fly ash with percentage elongation of 8.8%.
The fracture toughness of the fly ash containing composites was
however superior to those of composites without fly ash with 5wt%
fly ash containing composite exhibiting the highest fracture
toughness. The results show that fly ash can be utilized as
complementary reinforcement in ZA-27 alloy matrix composite to
reduce cost.
Abstract: This work explores the inter-region investment
behaviors of Integrated Circuit (IC) design industry from Taiwan to
China using the amount of foreign direct investment (FDI). According
to the mutual dependence among different IC design industrial
locations, Lotka-Volterra model is utilized to explore the FDI
interactions between South and East China. Effects of inter-regional
collaborations on FDI flows into China are considered. The analysis
results show that FDIs into South China for IC design industry
significantly inspire the subsequent FDIs into East China, while FDIs
into East China for Taiwan’s IC design industry significantly hinder
the subsequent FDIs into South China. Because the supply chain along
IC industry includes upstream IC design, midstream manufacturing, as
well as downstream packing and testing enterprises, IC design industry
has to cooperate with IC manufacturing, packaging and testing
industries in the same area to form a strong IC industrial cluster.
Taiwan’s IC design industry implement the largest FDI amount into
East China and the second largest FDI amount into South China
among the four regions: North, East, Mid-West and South China. If IC
design houses undertake more FDIs in South China, those in East
China are urged to incrementally implement more FDIs into East
China to maintain the competitive advantages of the IC supply chain in
East China. On the other hand, as the FDIs in East China rise, the FDIs
in South China will successively decline since capitals have
concentrated in East China. In addition, this investigation proves that
the prediction of Lotka-Volterra model in FDI trends is accurate
because the industrial interactions between the two regions are
included. Finally, this work confirms that the FDI flows cannot reach a
stable equilibrium point, so the FDI inflows into East and South China
will expand in the future.
Abstract: The consumption of food contaminated with molds
(microscopic filamentous fungi) and their toxic metabolites results in
the development of food-borne mycotoxicosis. The spores of molds
are ubiquitously spread in the environment and can be detected
everywhere. Ochratoxin A is a toxic and potentially carcinogenic
fungal toxin found in a variety of food commodities. In this study, the
mycological quality of various ready-to-eat local and imported pork
meat and meat byproducts sold in Egyptian markets were assessed
and the presence of various molds was determined in pork used as a
raw material, edible organs as liver and kidney as well as in
fermented raw meat by-products. The study assessed the mycological
quality of pork raw meat and their by-products sold in commercial
shops in Cairo, Egypt. Mycological analysis was conducted on
(n=110) samples which included pig’s livers and kidneys from
Egyptian Bassatin slaughter house; local and imported processed
pork meat by-products from Egyptian pork markets. The isolates
were identified using traditional mycological and biochemical tests.
All kidney and liver samples were positive to molds growth while all
byproducts were negative. Ochratoxin A levels were quantitatively
analyzed using the high performance liquid chromatography (HPLC)
and the highest results were present in kidney 7.51 part per billion
(ppb) followed by minced meat 6.19 ppb generally the local samples
showed higher levels than the imported ones. To the best of our
knowledge, this is the first report on mycotoxins detection and
quantification from pork by-products in Egypt.
Abstract: Structural failure is caused mainly by damage that
often occurs on structures. Many researchers focus on to obtain very
efficient tools to detect the damage in structures in the early state. In
the past decades, a subject that has received considerable attention in
literature is the damage detection as determined by variations in the
dynamic characteristics or response of structures. The study presents
a new damage identification technique. The technique detects the
damage location for the incomplete structure system using output
data only. The method indicates the damage based on the free
vibration test data by using ‘Two Points Condensation (TPC)
technique’. This method creates a set of matrices by reducing the
structural system to two degrees of freedom systems. The current
stiffness matrices obtain from optimization the equation of motion
using the measured test data. The current stiffness matrices compare
with original (undamaged) stiffness matrices. The large percentage
changes in matrices’ coefficients lead to the location of the damage. TPC technique is applied to the experimental data of a simply
supported steel beam model structure after inducing thickness change
in one element, where two cases consider. The method detects the
damage and determines its location accurately in both cases. In
addition, the results illustrate these changes in stiffness matrix can be
a useful tool for continuous monitoring of structural safety using
ambient vibration data. Furthermore, its efficiency proves that this
technique can be used also for big structures.
Abstract: This paper reports on the response of a fiber-optic
sensing probe to small concentrations of hydrogen peroxide (H2O2)
vapor at room temperature. H2O2 has extensive applications in industrial and medical
environments. Conversely, H2O2 can be a health hazard by itself. For
example, H2O2 induces cellular damage in human cells and its
presence can be used to diagnose illnesses such as asthma and human
breast cancer. Hence, development of reliable H2O2 sensor is of vital
importance to detect and measure this species. Ferric ferrocyanide, referred to as Prussian Blue (PB), was
deposited on the tip of a multimode optical fiber through the single
source precursor technique and served as an indicator of H2O2 in a
spectroscopic manner. Sensing tests were performed in H2O2-H2O
vapor mixtures with different concentrations of H2O2. The results of sensing tests show the sensor is able to detect H2O2
concentrations in the range of 50.6 ppm to 229.5 ppm. Furthermore,
the sensor response to H2O2 concentrations is linear in a log-log scale
with the adjacent R-square of 0.93. This sensing behavior allows us
to detect and quantify the concentration of H2O2 in the vapor phase.
Abstract: Urban areas, as they have been developed and operate
today, are areas of accumulation of a significant amount of people
and a large number of activities that generate desires and reasons for
traveling. The territorial expansion of the cities as well as the need to
preserve the importance of the central city areas lead to the
continuous increase of transportation needs which in the limited
urban space results in creating serious traffic and operational
problems. The modern perception of urban planning is directed towards more
holistic approaches and integrated policies that make it economically
competitive, socially just and more environmentally friendly. Over
the last 25 years, the goal of sustainable transport development has
been central to the agenda of any plan or policy for the city. The
modern planning of urban space takes into account the economic and
social aspects of the city and the importance of the environment to
sustainable urban development. In this context, the European Union
promotes direct or indirect related interventions according to the
cohesion and environmental policies; many countries even had the
chance to actually test them. This paper explores the methods and processes that have been
developed towards this direction and presents a review and
systematic presentation of this work. The ultimate purpose of this
research is to effectively use this review to create a decision making
methodological framework which can be the basis of a useful
operational tool for sustainable urban planning.
Abstract: Social Avoidance is one of the most important
problems that face a good number of disabled students. It results from
the negative attitudes of non-disabled students, teachers and others.
Some of the past research has shown that non-disabled individuals
hold negative attitudes toward persons with disabilities. The present
study aims to alleviate Social Avoidance by applying the Cognitive
Behavioral Intervention. 24 Blind students aged 19–24 (university students) were randomly
chosen we compared an experimental group (consisted of 12
students) who went through the intervention program, with a control
group (12 students also) who did not go through such intervention.
We used the Social Avoidance and Distress Scale (SADS) to assess
social anxiety and distress behavior. The author used many
techniques of cognitive behavioral intervention such as modeling,
cognitive restructuring, extension, contingency contracts, selfmonitoring,
assertiveness training, role play, encouragement and
others. Statistically, T-test was employed to test the research
hypothesis. Result showed that there is a significance difference between the
experimental group and the control group after the intervention and
also at the follow up stages of the Social Avoidance and Distress
Scale. Also for the experimental group, there is a significance
difference before the intervention and the follow up stages for the
scale. Results showed that, there is a decrease in social avoidance.
Accordingly, cognitive behavioral intervention program was
successful in decreasing social avoidance for blind students.