Abstract: Pressure vessels are usually operating at temperatures
where the conditions of linear elastic fracture mechanics are no
longer met because massive plasticity precedes crack propagation. In
this work the development of a surface crack in a pressure vessel
subject to bending and tension under elastic-plastic fracture
mechanics conditions was investigated. Finite element analysis was
used to evaluate the hydrostatic stress, the J-integral and crack
growth for semi-elliptical surface-breaking cracks. The results
showed non-uniform stress triaxiality and crack driving force around
the crack front at large deformation levels. Different ductile crack
extensions were observed which emphasis the dependent of ductile
tearing on crack geometry and type of loading. In bending the crack
grew only beneath the surface, and growth was suppressed at the
deepest segment. This contrasts to tension where the crack breaks
through the thickness with uniform growth along the entire crack
front except at the free surface. Current investigations showed that
the crack growth developed under linear elastic fracture mechanics
conditions will no longer be applicable under ductile tearing
scenarios.
Abstract: As known that efficiency of photovoltaic cells is not
high as desired level. Efficiency of PVs could be improved by
selecting convenient locations that have high solar irradiation,
sunshine duration, mild temperature, low level air pollution and dust
concentration. Additionally, some environmental parameters called
derating factors effect to decrease PV efficiencies such as cloud, high
temperature, aerosol optical depth, high dust concentration, shadow,
snow, humidity etc. In this paper, all parameters that effect PV
efficiency are considered in detail under climatic conditions of
Istanbul. A 750 Wp PV system with measurement devices is
constructed in Maslak campus of Istanbul Technical University.
Abstract: In the present work, an attempt has been made to
understand the feasibility of using UHF technique for identification
of any corona discharges/ arcing in insulating material due to water
droplets. The sensors of broadband type are useful for identification
of such discharges. It is realised that arcing initiated by liquid droplet
radiates UHF signals in the entire bandwidth up to 2 GHz. The
frequency content of the UHF signal generated due to corona/arcing
is not much varied in epoxy nanocomposites with different weight
percentage of clay content. The exfoliated/intercalated properties
were analysed through TEM studies. It is realized that corona
initiated discharges are of intermittent process. The hydrophobicity
of the material characterized through contact angle measurement. It
is realized that low Wt % of nanoclay content in epoxy resin reduces
the surface carbonization due to arcing/corona discharges. The results
of the study with gamma irradiated specimen indicates that contact
angle, discharge inception time and evaporation time of the liquid are
much lower than the virgin epoxy nanocomposite material.
Abstract: In today-s competitive global business environment,
the concept of supply chain management (SCM) continues to become
increasingly market-oriented, shifting the primary driver of the value
chain from supply to demand. Recent recommendations encourage
researchers to focus investigations on the supply chain process
integration (SCPI) capabilities that integrate a focal firm with its
network of suppliers and business customers to create value for it.
However, theoretical and empirical researches pertaining to the
antecedents and consequences of a focal firm-s SCPI capabilities have
been limited and piecemeal. The purpose of this study is to investigate
the critical determinants and consequences of a focal firm-s SCPI
capabilities. We test our proposed research framework using a sample
of 139 sales managers of manufacturing industries in Taiwan, our
research findings show that (1) both perceived business customer-s
power and focal firm-s market-oriented culture positively influences a
focal firm-s SCPI capabilities, and (2) SCPI capabilities positively
influence a focal firm-s SCM performance, both operational and
strategic benefits. Implications for practitioners and researchers and
suggestions for future research are also addressed in this study.
Abstract: Quaternary InxAlyGa1-x-yN semiconductors have
attracted much research interest because the use of this quaternary
offer the great flexibility in tailoring their band gap profile while
maintaining their lattice-matching and structural integrity. The
structural and optical properties of InxAlyGa1-x-yN alloys grown by
molecular beam epitaxy (MBE) is presented. The structural quality of
InxAlyGa1-x-yN layers was characterized using high-resolution X-ray
diffraction (HRXRD). The results confirm that the InxAlyGa1-x-yN
films had wurtzite structure and without phase separation. As the In
composition increases, the Bragg angle of the (0002) InxAlyGa1-x-yN
peak gradually decreases, indicating the increase in the lattice constant
c of the alloys. FWHM of (0002) InxAlyGa1-x-yN decreases with
increasing In composition from 0 to 0.04, that could indicate the
decrease of quality of the samples due to point defects leading to
non-uniformity of the epilayers. UV-VIS spectroscopy have been used
to study the energy band gap of InxAlyGa1-x-yN. As the indium (In)
compositions increases, the energy band gap decreases. However, for
InxAlyGa1-x-yN with In composition of 0.1, the band gap shows a
sudden increase in energy. This is probably due to local alloy
compositional fluctuations in the epilayer. The bowing parameter
which appears also to be very sensitive on In content is investigated
and obtained b = 50.08 for quaternary InxAlyGa1-x-yN alloys. From
photoluminescence (PL) measurement, green luminescence (GL)
appears at PL spectrum of InxAlyGa1-x-yN, emitted for all x at ~530 nm
and it become more pronounced as the In composition (x) increased,
which is believed cause by gallium vacancies and related to isolated
native defects.
Abstract: Bursa, since the establishment of the Ottoman Empire,
being on the important trade roads and having a capital accumulation
as a result of silk production, was one of the first cities of
modernization activities applied. Bursa maintained its importance
even during the Republican Period and became one of the most
important cities of the country and today is the fourth biggest and the
industrialized city in Turkey. Social, political, economical and
cultural changes occured with the reforms starting with the 1839
Edict of Tanzimat that aimed at modernizing the society and the
government and centralizing the political power began in the
Ottoman Empire. After the Tanzimat Reforms transformation of the
city changed and planning processes began in Bursa according to the
vision of Governors. The theresholds of the city are very important
data for a sustainable planning for the city planners. Main aim of this
study is to investigate the changes and transformations of the city
according to the changes in the socio-economical and cultural
properties for the city planners.
Abstract: Dehydration of methanol to dimethyl ether (DME)
over a commercial Al2O3 catalyst was studied in an isothermal integral
fixed bed reactor. The experiments were performed on the temperature
interval 513-613 K, liquid hourly space velocity (LHSV) of 0.9-2.1h-1,
pressures between 0.1 and 1.0 MPa. The effect of different operation
conditions on the dehydration of methanol was investigated in a
laboratory scale experiment. A new intrinsic kinetics equation based
on the mechanism of Langmuir-Hinshelwood dissociation adsorption
was developed for the dehydration reaction by fitting the expressions
to the experimental data. An activation energy of 67.21 kJ/mol was
obtained for the catalyst with the best performance. Statistic test
showed that this new intrinsic kinetics equation was acceptable.
Abstract: In the study of chironomids in Armenia several
species of Orthocladiinae subfamily of Cricotopus genus,
Diamesinae subfamily of Diamesa genus, and Chironominae
subfamily of Chironomus genus, have been identified. In the
Cricotopus genus two sibling species were found, not distinguishable
by larval morphological features, but clearly distinct cytogenetically.
Abstract: A prototype of an anomaly detection system was
developed to automate process of recognizing an anomaly of
roentgen image by utilizing fuzzy histogram hyperbolization image
enhancement and back propagation artificial neural network.
The system consists of image acquisition, pre-processor, feature
extractor, response selector and output. Fuzzy Histogram
Hyperbolization is chosen to improve the quality of the roentgen
image. The fuzzy histogram hyperbolization steps consist of
fuzzyfication, modification of values of membership functions and
defuzzyfication. Image features are extracted after the the quality of
the image is improved. The extracted image features are input to the
artificial neural network for detecting anomaly. The number of nodes
in the proposed ANN layers was made small.
Experimental results indicate that the fuzzy histogram
hyperbolization method can be used to improve the quality of the
image. The system is capable to detect the anomaly in the roentgen
image.
Abstract: In this paper back-propagation artificial neural network
(BPANN )with Levenberg–Marquardt algorithm is employed to
predict the deformation of the upsetting process. To prepare a
training set for BPANN, some finite element simulations were
carried out. The input data for the artificial neural network are a set
of parameters generated randomly (aspect ratio d/h, material
properties, temperature and coefficient of friction). The output data
are the coefficient of polynomial that fitted on barreling curves.
Neural network was trained using barreling curves generated by
finite element simulations of the upsetting and the corresponding
material parameters. This technique was tested for three different
specimens and can be successfully employed to predict the
deformation of the upsetting process
Abstract: Most standard software development methodologies
are often not applied to software projects in many developing
countries of the world. The approach generally practice is close to
what eXtreme Programming (XP) is likely promoting, just keep
coding and testing as the requirement evolves. XP is an agile
software process development methodology that has inherent
capability for improving efficiency of Business Software
Development (BSD). XP can facilitate Business-to-Development
(B2D) relationship due to its customer-oriented advocate. From
practitioner point of view, we applied XP to BSD and result shows
that customer involvement has positive impact on productivity, but
can as well frustrate the success of the project. In an effort to
promote software engineering practice in developing countries of
Africa, we present the experiment performed, lessons learned,
problems encountered and solution adopted in applying XP
methodology to BSD.
Abstract: Flexible manufacturing system is a system that is able to respond to changed conditions. In general, this flexibility is divided into two key categories and several subcategories. The first category is the so called machine flexibility which enables to make various products by the given machinery. The second category is routing flexibility enabling to execute the same operation by various machines. Flexible manufacturing systems usually consist of three main parts: CNC machine tools, transport system and control system. A higher level of flexible manufacturing systems is represented by the so called intelligent manufacturing systems.
Abstract: Trust and Energy consumption is the most challenging
issue in routing protocol design for Mobile ad hoc networks
(MANETs), since mobile nodes are battery powered and nodes
behaviour are unpredictable. Furthermore replacing and recharging
batteries and making nodes co-operative is often impossible in
critical environments like military applications. In this paper, we
propose a trust based energy aware routing model in MANET.
During route discovery, node with more trust and maximum energy
capacity is selected as a router based on a parameter called
'Reliability'. Route request from the source is accepted by a node
only if its reliability is high. Otherwise, the route request is
discarded. This approach forms a reliable route from source to
destination thus increasing network life time, improving energy
utilization and decreasing number of packet loss during transmission.
Abstract: The implementation of the new software and hardware-s technologies for tritium processing nuclear plants, and especially those with an experimental character or of new technology developments shows a coefficient of complexity due to issues raised by the implementation of the performing instrumentation and equipment into a unitary monitoring system of the nuclear technological process of tritium removal. Keeping the system-s flexibility is a demand of the nuclear experimental plants for which the change of configuration, process and parameters is something usual. The big amount of data that needs to be processed stored and accessed for real time simulation and optimization demands the achievement of the virtual technologic platform where the data acquiring, control and analysis systems of the technological process can be integrated with a developed technological monitoring system. Thus, integrated computing and monitoring systems needed for the supervising of the technological process will be executed, to be continued with the execution of optimization system, by choosing new and performed methods corresponding to the technological processes within the tritium removal processing nuclear plants. The developing software applications is executed with the support of the program packages dedicated to industrial processes and they will include acquisition and monitoring sub-modules, named “virtually" as well as the storage sub-module of the process data later required for the software of optimization and simulation of the technological process for tritium removal. The system plays and important role in the environment protection and durable development through new technologies, that is – the reduction of and fight against industrial accidents in the case of tritium processing nuclear plants. Research for monitoring optimisation of nuclear processes is also a major driving force for economic and social development.
Abstract: In this paper, we propose a new architecture for the implementation of the N-point Fast Fourier Transform (FFT), based on the Radix-2 Decimation in Frequency algorithm. This architecture is based on a pipeline circuit that can process a stream of samples and produce two FFT transform samples every clock cycle. Compared to existing implementations the architecture proposed achieves double processing speed using the same circuit complexity.
Abstract: Today, incorrect use of lands and land use changes,
excessive grazing, no suitable using of agricultural farms, plowing on
steep slopes, road construct, building construct, mine excavation etc
have been caused increasing of soil erosion and sediment yield. For
erosion and sediment estimation one can use statistical and empirical
methods. This needs to identify land unit map and the map of
effective factors. However, these empirical methods are usually time
consuming and do not give accurate estimation of erosion. In this
study, we applied GIS techniques to estimate erosion and sediment of
Menderjan watershed at upstream Zayandehrud river in center of
Iran. Erosion faces at each land unit were defined on the basis of land
use, geology and land unit map using GIS. The UTM coordinates of
each erosion type that showed more erosion amounts such as rills and
gullies were inserted in GIS using GPS data. The frequency of
erosion indicators at each land unit, land use and their sediment yield
of these indices were calculated. Also using tendency analysis of
sediment yield changes in watershed outlet (Menderjan hydrometric
gauge station), was calculated related parameters and estimation
errors. The results of this study according to implemented watershed
management projects can be used for more rapid and more accurate
estimation of erosion than traditional methods. These results can also
be used for regional erosion assessment and can be used for remote
sensing image processing.
Abstract: This paper investigates vortex shedding processes
occurring at the end of a stack of parallel plates, due to an oscillating
flow induced by an acoustic standing wave within an acoustic
resonator. Here, Particle Image Velocimetry (PIV) is used to quantify
the vortex shedding processes within an acoustic cycle
phase-by-phase, in particular during the “ejection" of the fluid out of
the stack. Standard hot-wire anemometry measurement is also applied
to detect the velocity fluctuations near the end of the stack.
Combination of these two measurement techniques allowed a detailed
analysis of the vortex shedding phenomena. The results obtained show
that, as the Reynolds number varies (by varying the plate thickness
and drive ratio), different flow patterns of vortex shedding are
observed by the PIV measurement. On the other hand, the
time-dependent hot-wire measurements allow obtaining detailed
frequency spectra of the velocity signal, used for calculating
characteristic Strouhal numbers. The impact of the plate thickness and
the Reynolds number on the vortex shedding pattern has been
discussed. Furthermore, a detailed map of the relationship between the
Strouhal number and Reynolds number has been obtained and
discussed.
Abstract: The objective of the research was to evaluate the
hardness stability of milk pomade sweets packed in several
packaging materials (OPP, Multibarrier 60 HFP, BIALON 65
HFP, BIALON 50 HFP, ECOLEAN) by several packaging
technologies – modified atmosphere (MAP) (consisting of
30% CO2+70% N2; 30% N2+70% CO2 and 100% CO2) and
control – in air ambiance. Samples were stored at the room
temperature +21±1 °C. The studies of the samples were
carried out before packaging and after 2, 4, 6, 8, and 10
storage weeks.
Abstract: The iris recognition technology is the most accurate,
fast and less invasive one compared to other biometric techniques
using for example fingerprints, face, retina, hand geometry, voice or
signature patterns. The system developed in this study has the
potential to play a key role in areas of high-risk security and can
enable organizations with means allowing only to the authorized
personnel a fast and secure way to gain access to such areas. The
paper aim is to perform the iris region detection and iris inner and
outer boundaries localization. The system was implemented on
windows platform using Visual C# programming language. It is easy
and efficient tool for image processing to get great performance
accuracy. In particular, the system includes two main parts. The first
is to preprocess the iris images by using Canny edge detection
methods, segments the iris region from the rest of the image and
determine the location of the iris boundaries by applying Hough
transform. The proposed system tested on 756 iris images from 60
eyes of CASIA iris database images.
Abstract: Australia, while being a large and eager consumer of
innovative and cutting edge Information and Communication
Technologies (ICT), continues to struggle to remain a leader in
Technological Innovation. This paper has two main contributions to
address certain aspects of this complex issue. The first being the
current findings of an ongoing research project on Information and
Innovation Management in the Australian Information and
Communication Technologies (ICT) sector. The major issues being
considered by the project include: investigation of the possible
inherent entrepreneurial nature of ICT; how to foster ICT innovation;
and examination of the inherent difficulties currently found within
the ICT industry of Australia in regards to supporting the
development of innovative and creative ideas. The second major
contribution is details of the I.-C.A.N. (Innovation by Collaborative
Anonymous Networking) software application information
management tool created and evolving in our research group. I-CAN,
besides having a positive reinforcement acronym, is aimed at
facilitating productive collaborative innovation in an Australian
workplace. Such a work environment is frequently subjected to
cultural influences such as the 'tall poppy syndrome' and 'negative'
or 'unconstructive' peer-pressure. There influences are frequently
seen as inhibitors to employee participation, entrepreneurship and
innovation.