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: The IEEE802.16 standard which has emerged as
Broadband Wireless Access (BWA) technology, promises to deliver
high data rate over large areas to a large number of subscribers in the
near future. This paper analyze the effect of overheads over capacity
of downlink (DL) of orthogonal frequency division multiple access
(OFDMA)–based on the IEEE802.16e mobile WiMAX system with
and without overheads. The analysis focuses in particular on the
impact of Adaptive Modulation and Coding (AMC) as well as
deriving an algorithm to determine the maximum numbers of
subscribers that each specific WiMAX sector may support. An
analytical study of the WiMAX propagation channel by using Cost-
231 Hata Model is presented. Numerical results and discussion
estimated by using Matlab to simulate the algorithm for different
multi-users parameters.
Abstract: This paper presents a conceptual model of agreement
options on negotiation support for civil engineering decision. The
negotiation support facilitates the solving of group choice decision
making problems in civil engineering decision to reduce the impact
of mud volcano disaster in Sidoarjo, Indonesia. The approach based
on application of analytical hierarchy process (AHP) method for
multi criteria decision on three level of decision hierarchy.
Decisions for reducing impact is very complicated since many
parties involved in a critical time. Where a number of stakeholders
are involved in choosing a single alternative from a set of solution
alternatives, there are different concern caused by differing
stakeholder preferences, experiences, and background. Therefore, a
group choice decision support is required to enable each stakeholder
to evaluate and rank the solution alternatives before engaging into
negotiation with the other stakeholders. Such civil engineering
solutions as alternatives are referred to as agreement options that are
determined by identifying the possible stakeholder choice, followed
by determining the optimal solution for each group of stakeholder.
Determination of the optimal solution is based on a game theory
model of n-person general sum game with complete information that
involves forming coalitions among stakeholders.
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: Tomato nutrition value, color, flavor of their fruits and products depends mainly on lycopene, β-carotene, ascorbic acid, sugars and their ratio. The two most important carotenoids in fruits of tomato are lycopene, which determined fruits red color, and β- carotene, which accounts for approximately 7% of the tomato carotenoids. Therefore, tomato products and their quality can be well characterized by the content of these elements.Maturity at harvest is very important to composition and quality of tomatoes. This is especially a problem with tomatoes picked green since it is difficult to differentiate between mature and immature-green fruits. Typical and advanced mature-green tomatoes will usually attain a much better flavor than those picked at the immature or partially mature stages.To better understand the synthesis of biochemical compounds, their concentration should be compared not only at the last stage of maturity, but also during all fruit ripening period in different varieties.
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: Power systems and transformer are intrinsic apparatus, therefore its reliability and safe operation is important to determine their operation conditions, and the industry uses quality control tests in the insulation design of oil filled transformers. Hence the service period effect on AC dielectric strength is significant. The effect of aging on transformer oil physical, chemical and electrical properties was studied using the international testing methods for the evaluation of transformer oil quality. The study was carried out on six transformers operate in the field and for monitoring periods over twenty years. The properties which are strongly time dependent were specified and those which have a great impact on the transformer oil acidity, breakdown voltage and dissolved gas analysis were defined. Several tests on the transformers oil were studied to know the time of purifying or changing it, moreover prediction of the characteristics of it under different operation conditions.
Abstract: Manufacturing tolerancing is intended to determine
the intermediate geometrical and dimensional states of the part
during its manufacturing process. These manufacturing dimensions
also serve to satisfy not only the functional requirements given in
the definition drawing, but also the manufacturing constraints, for
example geometrical defects of the machine, vibration and the
wear of the cutting tool. In this paper, an experimental study on the
influence of the wear of the cutting tool (systematic dispersions) is
explored. This study was carried out on three stages .The first stage
allows machining without elimination of dispersions (random,
systematic) so the tolerances of manufacture according to total
dispersions. In the second stage, the results of the first stage are
filtered in such way to obtain the tolerances according to random
dispersions. Finally, from the two previous stages, the systematic
dispersions are generated. The objective of this study is to model
by the least squares method the error of manufacture based on
systematic dispersion. Finally, an approach of optimization of the
manufacturing tolerances was developed for machining on a CNC
machine tool
Abstract: This paper presents an experimental investigation of
transformer dielectric response and solid insulation water content.
The dielectric response was carried out on the base of Hybrid
Frequency Dielectric Spectroscopy and Polarization Current
measurements method (FDS &PC). The calculation of the water
content in paper is based on the water content in oil and the obtained
equilibrium curves. A reference measurements were performed at
equilibrium conditions for water content in oil and paper of
transformer at different stable temperatures (25, 50, 60 and 70°C) to
prepare references to evaluate the insulation behavior at the not
equilibrium conditions. Some measurements performed at the
different simulated normal working modes of transformer operation
at the same temperature where the equilibrium conditions. The
obtained results show that when transformer temperature is mach
more than the its ambient temperature, the transformer temperature
decreases immediately after disconnecting the transformer from the
network and this temperature reduction influences the transformer
insulation condition in the measuring process. In addition to the oil
temperature at the near places to the sensors, the temperature
uniformity in transformer which can be changed by a big change in
the load of transformer before the measuring time will influence the
result. The investigations have shown that the extremely influence of
the time between disconnecting the transformer and beginning the
measurements on the results. And the online monitoring for water
content in paper measurements, on the basis of the oil water content
on line monitoring and the obtained equilibrium curves. The
measurements where performed continuously and for about 50 days
without any disconnection in the prepared the adiabatic room.
Abstract: In construction of any structure, the aesthetic and utility values should be considered in such a way as to make the structure cost-effective. Most structures are composed of elements and joints which are very critical in any skeletal space structure because they majorly determine the performance of the structure. In early times, most space structures were constructed using rigid joints which had the advantage of better performing structures as compared to pin-jointed structures but with the disadvantage of requiring all the construction work to be done on site. The discovery of semi-rigid joints now enables connections to be prefabricated and quickly assembled on site while maintaining good performance. In this paper, cost-effective is discussed basing on strength of connectors at the joints, buckling of joints and overall structure, and the effect of initial geometrical imperfections. Several existing joints are reviewed by classifying them into categories and discussing where they are most suited and how they perform structurally. Also, finite element modeling using ABAQUS is done to determine the buckling behavior. It is observed that some joints are more economical than others. The rise to span ratio and imperfections are also found to affect the buckling of the structures. Based on these, general principles that guide the design of cost-effective joints and structures are discussed.
Abstract: Most of ignition delay correlations studies have been
developed in a constant volume bombs which cannot capture the
dynamic variation in pressure and temperature during the ignition
delay as in real engines. Watson, Assanis et. al. and Hardenberg
and Hase correlations have been developed based on experimental
data of diesel engines. However, they showed limited predictive
ability of ignition delay when compared to experimental results. The
objective of the study was to investigate the dependency of ignition
delay time on engine brake power. An experimental investigation of
the effect of automotive diesel and water diesel emulsion fuels on
ignition delay under steady state conditions of a direct injection diesel
engine was conducted. A four cylinder, direct injection naturally
aspirated diesel engine was used in this experiment over a wide range
of engine speeds and two engine loads. The ignition delay
experimental data were compared with predictions of Assanis et. al.
and Watson ignition delay correlations. The results of the
experimental investigation were then used to develop a new ignition
delay correlation. The newly developed ignition delay correlation has
shown a better agreement with the experimental data than Assanis et.
al. and Watson when using automotive diesel and water diesel
emulsion fuels especially at low to medium engine speeds at both
loads. In addition, the second derivative of cylinder pressure which is
the most widely used method in determining the start of combustion
was investigated.
Abstract: This article analyses the relationship between
sovereign credit risk rating and gross domestic product for Central
and Eastern European Countries for the period 1996 – 2010. In order
to study the metioned relationship, we have used a numerical
transformation of the risk qualification, thus: we marked 0 the lowest
risk; then, we went on ascending, with a pace of 5, up to the score of
355 corresponding to the maximum risk. The used method of analysis
is that of econometric modelling with EViews 7.0. programme. This
software allows the analysis of data into a pannel type system,
involving a mix of periods of time and series of data for different
entities. The main conclusion of the work is the one confirming the
negative relationship between the sovereign credit risk and the gross
domestic product for the Central European and Eastern countries
during the reviewed period.
Abstract: This paper describes the application of a model predictive controller to the problem of batch reactor temperature control. Although a great deal of work has been done to improve reactor throughput using batch sequence control, the control of the actual reactor temperature remains a difficult problem for many operators of these processes. Temperature control is important as many chemical reactions are sensitive to temperature for formation of desired products. This controller consist of two part (1) a nonlinear control method GLC (Global Linearizing Control) to create a linear model of system and (2) a Model predictive controller used to obtain optimal input control sequence. The temperature of reactor is tuned to track a predetermined temperature trajectory that applied to the batch reactor. To do so two input signals, electrical powers and the flow of coolant in the coil are used. Simulation results show that the proposed controller has a remarkable performance for tracking reference trajectory while at the same time it is robust against noise imposed to system output.
Abstract: The one of best robust search technique on large scale
search area is heuristic and meta heuristic approaches. Especially in
issue that the exploitation of combinatorial status in the large scale
search area prevents the solution of the problem via classical
calculating methods, so such problems is NP-complete. in this
research, the problem of winner determination in combinatorial
auctions have been formulated and by assessing older heuristic
functions, we solve the problem by using of genetic algorithm and
would show that this new method would result in better performance
in comparison to other heuristic function such as simulated annealing
greedy approach.
Abstract: The purpose of the study was to determine the amount of Palm Kernel Oil (PKO) extracted from a packed bed of palm kernels in a supercritical fluid extractor using supercritical carbon dioxide (SC-CO2) as an environmental friendly solvent. Further, the study sought to ascertain the values of the overall mass transfer coefficient (K) of PKO evaluation through a mass transfer model, at constant temperature of 50 °C, 60 °C, and 70 °C and pressures range from 27.6 MPa, 34.5 MPa, 41.4 MPa and 48.3 MPa respectively. Finally, the study also seeks to demonstrate the application of the overall mass transfer coefficient values in relation to temperature and pressure. The overall mass transfer coefficient was found to be dependent pressure at each constant temperature of 50 °C, 60 °C and 70 °C. The overall mass transfer coefficient for PKO in a packed bed of palm kernels was found to be in the range of 1.21X 10-4 m min-1 to 1.72 X 10-4 m min-1 for a constant temperature of 50 °C and in the range of 2.02 X 10-4 m min-1 to 2.43 X 10-4 m min-1 for a constant temperature of 60 °C. Similar increasing trend of the overall mass transfer coefficient from 1.77 X 10-4 m min-1 to 3.64 X 10-4 m min-1 was also observed at constant temperature of 70 °C within the same pressure range from 27.6 MPa to 48.3 MPa.
Abstract: A novel method of individual level adaptive mutation rate control called the rank-scaled mutation rate for genetic algorithms is introduced. The rank-scaled mutation rate controlled genetic algorithm varies the mutation parameters based on the rank of each individual within the population. Thereby the distribution of the fitness of the papulation is taken into consideration in forming the new mutation rates. The best fit mutate at the lowest rate and the least fit mutate at the highest rate. The complexity of the algorithm is of the order of an individual adaptation scheme and is lower than that of a self-adaptation scheme. The proposed algorithm is tested on two common problems, namely, numerical optimization of a function and the traveling salesman problem. The results show that the proposed algorithm outperforms both the fixed and deterministic mutation rate schemes. It is best suited for problems with several local optimum solutions without a high demand for excessive mutation rates.
Abstract: The seismic feedback experiences in Algeria have
shown higher percentage of damages for non-code conforming
reinforced concrete (RC) buildings. Furthermore, the vulnerability of
these buildings was further aggravated due to presence of many
factors (e.g. weak the seismic capacity of these buildings, shorts
columns, Pounding effect, etc.).
Consequently Seismic risk assessments were carried out on
populations of buildings to identify the buildings most likely to
undergo losses during an earthquake. The results of such studies are
important in the mitigation of losses under future seismic events as
they allow strengthening intervention and disaster management plans
to be drawn up.
Within this paper, the state of the existing structures is assessed using
"the vulnerability index" method. This method allows the
classification of RC constructions taking into account both, structural
and non structural parameters, considered to be ones of the main
parameters governing the vulnerability of the structure. Based on
seismic feedback from past earthquakes DPM (damage probability
matrices) were developed too.
Abstract: This paper presents a practical scheme that can be used for allocating the transmission loss to generators and loads. In this scheme first the share of a generator or load on the current through a branch is determined using Z-bus modified matrix. Then the current components are decomposed and the branch loss allocation is obtained. A motivation of proposed scheme is to improve the results of Z-bus method and to reach more fair allocation. The proposed scheme has been implemented and tested on several networks. To achieve practical and applicable results, the proposed scheme is simulated and compared on the transmission network (400kv) of Khorasan region in Iran and the 14-bus standard IEEE network. The results show that the proposed scheme is comprehensive and fair to allocating the energy losses of a power market to its participants.