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: This paper aims to determine Fundamental Natural
Frequency (FNF) of a structural composite floor system known as
Chromite. To achieve this purpose, FNFs of studied panels are
determined by development of Finite Element Models (FEMs) in
ABAQUS program. American Institute of Steel Construction (AISC)
code in Steel Design Guide Series 11 presents a fundamental formula
to calculate FNF of a steel framed floor system. This formula has
been used to verify results of the FEMs. The variability in the FNF of
the studied system under various parameters such as dimensions of
floor, boundary conditions, rigidity of main and secondary beams
around the floor, thickness of concrete slab, height of composite
joists, distance between composite joists, thickness of top and bottom
flanges of the open web steel joists, and adding tie beam
perpendicular on the composite joists, is determined. The results
show that changing in dimensions of the system, its boundary
conditions, rigidity of main beam, and also adding tie beam,
significant changes the FNF of the system up to 452.9%, 50.8%, -
52.2%, %52.6%, respectively. In addition, increasing thickness of
concrete slab increases the FNF of the system up to 10.8%.
Furthermore, the results demonstrate that variation in rigidity of
secondary beam, height of composite joist, and distance between
composite joists, and thickness of top and bottom flanges of open
web steel joists insignificant changes the FNF of the studied system
up to -0.02%, -3%, -6.1%, and 0.96%, respectively. Finally, the
results of this study help designer predict occurrence of resonance,
comfortableness, and design criteria of the studied system.
Abstract: Asphalt concrete pavements have a short life cycle,
failing mainly due to temperature changes, traffic loading and ageing.
Modified asphalt mixtures provide the technology to produce a
bituminous binder with improved viscoelastic properties, which
remain in balance over a wider temperature range and loading
conditions. In this research, 60/70 penetration grade asphalt binder
was modified by adding 2, 4, 6, 8 and 10 percent by weight of asphalt
binder following the wet process and the mineral aggregate was
modified by adding 1, 2, 3, 4 and 5 percent crumb rubber by volume
of the mineral aggregate following the dry process. The LDPE
modified asphalt binder rheological properties were evaluated. The
laboratory results showed an increase in viscosity, softening point
and stiffness of the binder. The modified asphalt was then used in
preparing asphalt mixtures by Marshall Mix design procedure. The
Marshall Stability values for mixes containing 2% crumb rubber and
4% LDPE were found to be 30% higher than the conventional asphalt
concrete mix.
Abstract: This paper describes I²C Slave implementation using
I²C master obtained from the OpenCores website. This website
provides free Verilog and VHDL Codes to users. The design
implementation for the I²C slave is in Verilog Language and uses
EDA tools for ASIC design known as ModelSim from Mentor
Graphic. This tool is used for simulation and verification purposes.
Common application for this I²C Master-Slave integration is also
included. This paper also addresses the advantages and limitations of
the said design.
Abstract: This research studies the joint production,
maintenance and subcontracting control policy for an unreliable
deteriorating manufacturing system. Production activities are
controlled by a derivation of the Hedging Point Policy, and given that
the system is subject to deterioration, it reduces progressively its
capacity to satisfy product demand. Multiple deterioration effects are
considered, reflected mainly in the quality of the parts produced and
the reliability of the machine. Subcontracting is available as support
to satisfy product demand; also, overhaul maintenance can be
conducted to reduce the effects of deterioration. The main objective
of the research is to determine simultaneously the production,
maintenance and subcontracting rate, which minimize the total,
incurred cost. A stochastic dynamic programming model is
developed and solved through a simulation-based approach
composed of statistical analysis and optimization with the response
surface methodology. The obtained results highlight the strong
interactions between production, deterioration and quality, which
justify the development of an integrated model. A numerical example
and a sensitivity analysis are presented to validate our results.
Abstract: The Gezi Park protests of 2013 have significantly changed the Turkish agenda and its effects have been felt historically. The protests, which rapidly spread throughout the country, were triggered by the proposal to recreate the Ottoman Army Barracks to function as a shopping mall on Gezi Park located in Istanbul’s Taksim neighbourhood despite the oppositions of several NGOs and when trees were cut in the park for this purpose. Once the news that the construction vehicles entered the park on May 27 spread on social media, activists moved into the park to stop the demolition, against whom the police used disproportioned force. With this police intervention and the then prime-minister Tayyip Erdoğan's insistent statements about the construction plans, the protests turned into anti- government demonstrations, which then spread to the rest of the country, mainly in big cities like Ankara and Izmir. According to the Ministry of Internal Affairs’ June 23rd reports, 2.5 million people joined the demonstrations in 79 provinces, that is all of them, except for the provinces of Bayburt and Bingöl, while even more people shared their opinions via social networks. As a result of these events, 8 civilians and 2 security personnel lost their lives, namely police chief Mustafa Sarı, police officer Ahmet Küçükdağ, citizens Mehmet Ayvalıtaş, Abdullah Cömert, Ethem Sarısülük, Ali İsmail Korkmaz, Ahmet Atakan, Berkin Elvan, Burak Can Karamanoğlu, Mehmet İstif, and Elif Çermik, and 8163 more were injured. Besides being a turning point in Turkish history, the Gezi Park protests also had broad repercussions in both in Turkish and in global media, which focused on Turkey throughout the events. Our study conducts content analysis of three Turkish reporting newspapers with varying ideological standpoints, Hürriyet, Cumhuriyet ve Yeni Şafak, in order to reveal their basic approach to news casting in context of the Gezi Park protests. Headlines, news segments, and news content relating to the Gezi protests were treated and analysed for this purpose. The aim of this study is to understand the social effects of the Gezi Park protests through media samples with varying political attitudes towards news casting.
Abstract: The purpose of the present work was to develop an innovative food product with good textural and sensorial characteristics. The product, a new type of bread, was prepared with wheat (90%) and lupin (10%) flours, without the addition of any conservatives. Several experiences were also done to find the most appropriate proportion of lupin flour. The optimized product was characterized considering the rheological, physical-chemical and sensorial properties. The water absorption of wheat flour with 10% of lupin was higher than that of the normal wheat flours, and Wheat Ceres flour presented the lower value, with lower dough development time and high stability time. The breads presented low moisture but a considerable water activity. The density of bread decreased with the introduction of lupin flour. The breads were quite white, and during storage the colour parameters decreased. The lupin flour clearly increased the number of alveolus, but the total area increased significantly just for the Wheat Cerealis bread. The addition of lupin flour increased the hardness and chewiness of breads, but the elasticity did not vary significantly. Lupin bread was sensorially similar to wheat bread produced with WCerealis flour, and the main differences are the crust rugosity, colour and alveolus characteristics.
Abstract: Temperature effect on the performance of a photovoltaic module is one of the main concerns that face this renewable energy, especially in hot arid region, e.g. United Arab Emirates. Overheating of the PV modules reduces the open circuit voltage and the efficiency of the modules dramatically. In this work, water-cooling is developed to enhance the performance of PV modules. Different scenarios are tested under UAE weather conditions: front, back and double cooling. A spraying system is used for the front cooling whether a direct contact water system is used for the back cooling. The experimental results are compared to non-cooling module and the performance of the PV module is determined for different situations. The experimental results show that the front cooling is more effective than the back cooling and may decrease the temperature of the PV module significantly.
Abstract: The objective of this paper is to analyze the role played by the institute of the public hearings in the Brazilian Supreme Court. The public hearings are regulated since 1999 by the Brazilian Laws nº 9.868, nº 9.882 and by the Intern Regiment of the Brazilian Supreme Court. According to this legislation, the public hearings are supposed to be called when a matter of circumstance of fact must be clarified, what can be done through the hearing of the testimonies of persons with expertise and authority in the theme related to the cause. This work aims to investigate what is the role played by the public hearings and by the experts in the Brazilian Supreme Court. The hypothesis of this research is that: (I) The public hearings in the Brazilian Supreme Court are used to uphold a rhetoric of a democratic legitimacy of the Court`s decisions; (II) The Legislative intentions have been distorted. To test this hypothesis, the adopted methodology involves an empirical study of the Brazilian jurisprudence. As a conclusion, it follows that the public hearings convened by the Brazilian Supreme Court do not correspond, in practice, to the role assigned to them by the Congress since they do not serve properly to epistemic interests. The public hearings not only do not legitimate democratically the decisions, but also, do not properly clarify technical issues.
Abstract: The aim of this study was to investigate the
photocatalytic activity of polycrystalline phases of bismuth tungstate
of formula Bi2WO6. Polycrystalline samples were elaborated using a
coprecipitation technique followed by a calcination process at
different temperatures (300, 400, 600 and 900°C). The obtained
polycrystalline phases have been characterized by X-ray diffraction
(XRD), scanning electron microscopy (SEM), and transmission
electron microscopy (TEM). Crystal cell parameters and cell volume
depend on elaboration temperature. High-resolution electron
microscopy images and image simulations, associated with X-ray
diffraction data, allowed confirming the lattices and space groups
Pca21. The photocatalytic activity of the as-prepared samples was
studied by irradiating aqueous solutions of Rhodamine B, associated
with Bi2WO6 additives having variable crystallite sizes. The
photocatalytic activity of such bismuth tungstates increased as the
crystallite sizes decreased. The high specific area of the
photocatalytic particles obtained at 300°C seems to condition the
degradation kinetics of RhB.
Abstract: The purpose of this research was to investigate the
creep behaviour of the heterogeneous Timber-UHPFRC beams. New
developments have been done to further improve the structural
performance, such as strengthening of the timber (glulam) beam by
bonding composite material combine with an ultra-high performance
fibre reinforced concrete (UHPFRC) internally reinforced with or
without carbon fibre reinforced polymer (CFRP) bars. However, in
the design of wooden structures, in addition to the criteria of
strengthening and stiffness, deformability due to the creep of wood,
especially in horizontal elements, is also a design criterion. Glulam,
UHPFRC and CFRP may be an interesting composite mix to respond
to the issue of creep behaviour of composite structures made of
different materials with different rheological properties. In this paper,
we describe an experimental and analytical investigation of the creep
performance of the glulam-UHPFRC-CFRP beams assembled by
bonding. The experimental investigations creep behaviour was
conducted for different environments: in- and outside under constant
loading for approximately a year. The measured results are compared
with numerical ones obtained by an analytical model. This model was
developed to predict the creep response of the glulam-UHPFRCCFRP
beams based on the creep characteristics of the individual
components. The results show that heterogeneous glulam-UHPFRC
beams provide an improvement in both the strengthening and
stiffness, and can also effectively reduce the creep deflection of
wooden beams.
Abstract: We report the design and characterization of ultra high
quality factor filter based on one-dimensional photonic-crystal Thue-
Morse sequence structure. The behavior of aperiodic array of
photonic crystal structure is numerically investigated and we show
that by changing the angle of incident wave, desired wavelengths
could be tuned and a tunable filter is realized. Also it is shown that
high quality factor filter be achieved in the telecommunication
window around 1550 nm, with a device based on Thue-Morse
structure. Simulation results show that the proposed structure has a
quality factor more than 100000 and it is suitable for DWDM
communication applications.
Abstract: This paper presents the modeling approach in SBO
sequence for VVER 1000 reactors and describes the reactor core
behavior at late in-vessel phase in case of late reflooding by HPIS
and gives preliminary results for the ASTECv2 validation. The work
is focused on investigation of plant behavior during total loss of
power and the operator actions. The main goal of these analyses is to
assess the phenomena arising during the Station blackout (SBO)
followed by primary side high pressure injection system (HPIS)
reflooding of already damaged reactor core at very late “in-vessel”
phase. The purpose of the analyses is to define how the later HPIS
switching on can delay the time of vessel failure or possibly avoid
vessel failure. The times for HPP injection were chosen based on
previously performed investigations.
Abstract: Ultraviolet photocatalytic oxidation (UV-PCO)
technology has been recommended as a green approach to health
indoor environment when it is integrated into mechanical ventilation
systems for inorganic and organic compounds removal as well as
energy saving due to less outdoor air intakes. Although much research
has been devoted to UV-PCO, limited information is available on the
UV-PCO behavior tested by the mixtures in literature. This project
investigated UV-PCO performance and by-product generation using a
single and a mixture of acetone and MEK at 100 ppb each in a
single-pass duct system in an effort to obtain knowledge associated
with competitive photochemical reactions involved in. The
experiments were performed at 20 % RH, 22 °C, and a gas flow rate of
128 m3/h (75 cfm). Results show that acetone and MEK mutually
reduced each other’s PCO removal efficiency, particularly negative
removal efficiency for acetone. These findings were different from
previous observation of facilitatory effects on the adsorption of
acetone and MEK on photocatalyst surfaces.
Abstract: In this study, failure analysis of pipe system at a micro
hydroelectric power plant is investigated. Failure occurred at the pipe
system in the powerhouse during shut down operation of the water
flow by a valve. This locking had caused a sudden shock wave, also
called “Water-hammer effect”, resulting in noise and inside pressure
increase. After visual investigation of the effect of the shock wave on
the system, a circumference crack was observed at the pipe flange
weld region. To establish the reason for crack formation, calculations
of pressure and stress values at pipe, flange and welding seams were
carried out and concluded that safety factor was high (2.2), indicating
that no faulty design existed. By further analysis, pipe system and
hydroelectric power plant was examined. After observations it is
determined that the plant did not include a ventilation nozzle (air
trap), that prevents the system of sudden pressure increase inside the
pipes which is caused by water-hammer effect. Analyses were carried
out to identify the influence of water-hammer effect on inside
pressure increase and it was concluded that, according Jowkowsky’s
equation, shut down time is effective on inside pressure increase. The
valve closing time was uncertain but by a shut down time of even one
minute, inside pressure would increase by 7.6 bar (working pressure
was 34.6 bar). Detailed investigations were also carried out on the
assembly of the pipe-flange system by considering technical
drawings. It was concluded that the pipe-flange system was not
installed according to the instructions. Two of five weld seams were
not applied and one weld was carried out faulty. This incorrect and
inadequate weld seams resulted in; insufficient connection of the pipe
to the flange constituting a strong notch effect at weld seam regions,
increase in stress values and the decrease of strength and safety
factor.
Abstract: This paper addresses minimizing the makespan of the
distributed permutation flow shop scheduling problem. In this
problem, there are several parallel identical factories or flowshops
each with series of similar machines. Each job should be allocated to
one of the factories and all of the operations of the jobs should be
performed in the allocated factory. This problem has recently gained
attention and due to NP-Hard nature of the problem, metaheuristic
algorithms have been proposed to tackle it. Majority of the proposed
algorithms require large computational time which is the main
drawback. In this study, a general variable neighborhood search
algorithm (GVNS) is proposed where several time-saving schemes
have been incorporated into it. Also, the GVNS uses the sophisticated
method to change the shaking procedure or perturbation depending
on the progress of the incumbent solution to prevent stagnation of the
search. The performance of the proposed algorithm is compared to
the state-of-the-art algorithms based on standard benchmark
instances.
Abstract: Elliptic curve discrete logarithm problem(ECDLP) is
one of problems on which the security of pairing-based cryptography
is based. This paper considers Pollard’s rho method to evaluate
the security of ECDLP on Barreto-Naehrig(BN) curve that is an
efficient pairing-friendly curve. Some techniques are proposed to
make the rho method efficient. Especially, the group structure on
BN curve, distinguished point method, and Montgomery trick are
well-known techniques. This paper applies these techniques and
shows its optimization. According to the experimental results for
which a large-scale parallel system with MySQL is applied, 94-bit
ECDLP was solved about 28 hours by parallelizing 71 computers.
Abstract: Ecological systems are exposed and are influenced by
various natural and anthropogenic disturbances. They produce
various effects and states seeking response symmetry to a state of
global phase coherence or stability and balance of their food webs.
This research project addresses the development of a computational
methodology for modeling plankton food webs. The use of
algorithms to establish connections, the generation of representative
fuzzy multigraphs and application of technical analysis of complex
networks provide a set of tools for defining, analyzing and evaluating
community structure of coastal aquatic ecosystems, beyond the
estimate of possible external impacts to the networks. Thus, this
study aims to develop computational systems and data models to
assess how these ecological networks are structurally and
functionally organized, to analyze the types and degree of
compartmentalization and synchronization between oscillatory and
interconnected elements network and the influence of disturbances on
the overall pattern of rhythmicity of the system.
Abstract: Passive control methods can be utilized to build
earthquake resistant structures, and also to strengthen the vulnerable
ones. In this paper, we studied the effect of this system in increasing
the ductility and energy dissipation and also modeled the behavior of
this type of eccentric bracing, and compared the hysteresis diagram
of the modeled samples with the laboratory samples. We studied
several samples of frames with vertical shear-links in order to assess
the behavior of this type of eccentric bracing. Each of these samples
was modeled in finite element software ANSYS 9.0, and was
analyzed under the static cyclic loading. It was found that vertical
shear-links have a more stable hysteresis loops. Another analysis
showed that using honeycomb beams as the horizontal beam along
with steel reinforcement has no negative effect on the hysteresis
behavior of the sample.
Abstract: Useful lifetime evaluation of chevron rubber spring
was very important in design procedure to assure the safety and
reliability. It is, therefore, necessary to establish a suitable criterion
for the replacement period of chevron rubber spring. In this study, we
performed characteristic analysis and useful lifetime prediction of
chevron rubber spring. Rubber material coefficient was obtained by
curve fittings of uniaxial tension equibiaxial tension and pure shear
test. Computer simulation was executed to predict and evaluate the
load capacity and stiffness for chevron rubber spring. In order to
useful lifetime prediction of rubber material, we carried out the
compression set with heat aging test in an oven at the temperature
ranging from 50°C to 100°C during a period 180 days. By using the
Arrhenius plot, several useful lifetime prediction equations for rubber
material was proposed.