Abstract: In order to enhance the aircraft survivability, the
infrared signatures emitted by hot engine parts should be determined
exactly. For its reduction it is necessary for the rear fuselage
temperature to be decreased. In this study, numerical modeling of flow
fields and heat transfer characteristics of an aircraft nozzle is
performed and its temperature distribution along each component wall
is predicted. The radiation shield is expected to reduce the skin
temperature of rear fuselage. The effect of material characteristic of
radiation shield on the heat transfer is also investigated. Through this
numerical analysis, design parameters related to the susceptibility of
aircraft are examined.
Abstract: This work presents a comparison between the Annual
Energy Output (AEO) of two commercial vertical-axis wind turbines
(VAWTs) for a low-wind urban site: both a drag-driven and a liftdriven
concepts are examined in order to be installed on top of the
new Via dei Giustinelli building, Trieste (Italy). The power-curves,
taken from the product specification sheets, have been matched to the
wind characteristics of the selected installation site. The influence of
rotor swept area and rated power on the performance of the two
proposed wind turbines have been examined in detail, achieving a
correlation between rotor swept area, electrical generator size and
wind distribution, to be used as a guideline for the calculation of the
AEO.
Abstract: This purpose of this paper is to present the acceptance single sampling plan when the fraction of nonconforming items is a fuzzy number and being modeled based on the fuzzy Poisson distribution. We have shown that the operating characteristic (oc) curves of the plan is like a band having a high and low bounds whose width depends on the ambiguity proportion parameter in the lot when that sample size and acceptance numbers is fixed. Finally we completed discuss opinion by a numerical example. And then we compared the oc bands of using of binomial with the oc bands of using of Poisson distribution.
Abstract: The production of biodiesel from crude palm oil with
a homogeneous base catalyst is unlikely owing to considerable
formation of soap. Free fatty acids (FFA) in crude palm oil need to
be reduced, e.g. by esterification. This study investigated the activity
of sulfated zirconia calcined at various temperatures for esterification
of FFA in crude palm oil to biodiesel. It was found that under a
proper reaction condition, sulfated zirconia well catalyzes
esterification. FFA content can be reduced to an acceptable value for
typical biodiesel production with a homogeneous base catalyst.
Crystallinity and sulfate attachment of sulfated zirconia depend on
calcination temperature during the catalyst preparation. Too low
temperature of calcination gives amorphous sulfated zirconia which
has low activity for esterification of FFA. In contrast, very high
temperature of calcination removes sulfate group, consequently,
conversion of FFA is reduced. The appropriate temperature range of
calcination is 550-650 oC.
Abstract: In order to achieve effective management, the professional and individual characteristics and qualifications of school principals and their system-oriented perception is very important. Therefore, it is necessary to conduct regular comprehensive studies into the profiles of school principals. The purpose of this study is to determine the perceptions of primary school principals about their working conditions and to present their professional profiles. The questionnaire was distributed to 1475 respondents and 1428 valid questionnaires were evaluated. The results of the research were discussed and compared to other similar studies.Keywordseducation, education management, primary school principal, principals profiles
Abstract: Data warehouse is a dedicated database used for querying and reporting. Queries in this environment show special characteristics such as multidimensionality and aggregation. Exploiting the nature of queries, in this paper we propose a query driven design framework. The proposed framework is general and allows a designer to generate a schema based on a set of queries.
Abstract: Today automobile and aerospace industries realise Laser Beam Welding for a clean and non contact source of heating and fusion for joining of sheets. The welding performance is mainly based on by the laser welding parameters. Some concepts related to Artificial Neural Networks and how can be applied to model weld bead geometry and mechanical properties in terms of equipment parameters are reported in order to evaluate the accuracy and compare it with traditional modeling schemes. This review reveals the output features of Titanium and Aluminium weld bead geometry and mechanical properties such as ultimate tensile strength, yield strength, elongation and reduction of the area of the weld using Artificial Neural Network.
Abstract: Industrial robots play a vital role in automation
however only little effort are taken for the application of robots in
machining work such as Grinding, Cutting, Milling, Drilling,
Polishing etc. Robot parallel manipulators have high stiffness,
rigidity and accuracy, which cannot be provided by conventional
serial robot manipulators. The aim of this paper is to perform the
modeling and the workspace analysis of a 3 DOF Parallel
Manipulator (3 DOF PM). The 3 DOF PM was modeled and
simulated using 'ADAMS'. The concept involved is based on the
transformation of motion from a screw joint to a spherical joint
through a connecting link. This paper work has been planned to
model the Parallel Manipulator (PM) using screw joints for very
accurate positioning. A workspace analysis has been done for the
determination of work volume of the 3 DOF PM. The position of the
spherical joints connected to the moving platform and the
circumferential points of the moving platform were considered for
finding the workspace. After the simulation, the position of the joints
of the moving platform was noted with respect to simulation time and
these points were given as input to the 'MATLAB' for getting the
work envelope. Then 'AUTOCAD' is used for determining the work
volume. The obtained values were compared with analytical
approach by using Pappus-Guldinus Theorem. The analysis had been
dealt by considering the parameters, link length and radius of the
moving platform. From the results it is found that the radius of
moving platform is directly proportional to the work volume for a
constant link length and the link length is also directly proportional
to the work volume, at a constant radius of the moving platform.
Abstract: This paper presented a collaborative education model,
which consists four parts: collaborative teaching, collaborative
working, collaborative training and interaction. Supported by an
e-learning platform, collaborative education was practiced in a data
structure e-learning course. Data collected shows that most of students
accept collaborative education. This paper goes one step attempting to
determine which aspects appear to be most important or helpful in
collaborative education.
Abstract: This work deals with problems of tool axis inclination angles in ball-end milling. Tool axis inclination angle contributes to improvement of functional surface properties (surface integrity - surface roughness, residual stress, micro hardness, etc.), decreasing cutting forces and improving production. By milling with ball-end milling tool, using standard way of cutting, when work piece and cutting tool contain right angle, we have zero cutting speed on edge. At this point cutting tool only pushes material into the work piece. Here we can observe the following undesirable effects - chip contraction, increasing of cutting temperature, increasing vibrations or creation of built-up edge. These effects have negative results – low quality of surface and decreasing of tool life (in the worse case even it is pinching out). These effects can be eliminated with the tilt of cutting tool or tilt of work piece.
Abstract: A total of twenty tensile biopsies were collected from
children undergoing tonsillectomy from teaching hospital ENT
department and Kurdistan private hospital in sulaimani city. All
biopsies were homogenized and cultured; the obtained bacterial
isolates were purified and identified by biochemical tests and VITEK
2 compact system. Among the twenty studied samples, only one
Pseudomonas putida with probability of 99% was isolated.
Antimicrobial susceptibility was carried out by disk diffusion
method, Pseudomonas putida showed resistance to all antibiotics
used except vancomycin. The isolate further subjected to PCR and
DNA sequence analysis of blaVIM gene using different set of primers
for different regions of VIM gene. The results were found to be PCR
positive for the blaVIM gene. To determine the sequence of blaVIM
gene, DNA sequencing performed. Sequence alignment of blaVIM
gene with previously recorded blaVIM gene in NCBI- database showed
that P. putida isolate have different blaVIM gene.
Abstract: The effect of different combinations of response
feedback on the performance of active control system on nonlinear
frames has been studied in this paper. To this end different feedback
combinations including displacement, velocity, acceleration and full
response feedback have been utilized in controlling the response of
an eight story bilinear hysteretic frame which has been subjected to a
white noise excitation and controlled by eight actuators which could
fully control the frame. For active control of nonlinear frame
Newmark nonlinear instantaneous optimal control algorithm has been
used which a diagonal matrix has been selected for weighting
matrices in performance index. For optimal design of active control
system while the objective has been to reduce the maximum drift to
below the yielding level, Distributed Genetic Algorithm (DGA) has
been used to determine the proper set of weighting matrices. The
criteria to assess the effect of each combination of response feedback
have been the minimum required control force to reduce the
maximum drift to below the yielding drift. The results of numerical
simulation show that the performance of active control system is
dependent on the type of response feedback where the velocity
feedback is more effective in designing optimal control system in
comparison with displacement and acceleration feedback. Also using
full feedback of response in controller design leads to minimum
control force amongst other combinations. Also the distributed
genetic algorithm shows acceptable convergence speed in solving the
optimization problem of designing active control systems.
Abstract: Within the last years, several technologies have been developed to help building e-learning portals. Most of them follow approaches that deliver a vast amount of functionalities, suitable for class-like learning. The SuGI project, as part of the D-Grid (funded by the BMBF), targets on delivering a highly scalable and sustainable learning solution to provide materials (e.g. learning modules, training systems, webcasts, tutorials, etc.) containing knowledge about Grid computing to the D-Grid community. In this article, the process of the development of an e-learning portal focused on the requirements of this special user group is described. Furthermore, it deals with the conceptual and technical design of an e-learning portal, addressing the special needs of heterogeneous target groups. The main focus lies on the quality management of the software development process, Web templates for uploading new contents, the rich search and filter functionalities which will be described from a conceptual as well as a technical point of view. Specifically, it points out best practices as well as concepts to provide a sustainable solution to a relatively unknown and highly heterogeneous community.
Abstract: This paper introduces a new instantaneous frequency
computation approach -Counting Instantaneous Frequency for a
general class of signals called simple waves. The classsimple wave
contains a wide range of continuous signals for which the concept
instantaneous frequency has a perfect physical sense. The concept of
-Counting Instantaneous Frequency also applies to all the discrete data.
For all the simple wave signals and the discrete data, -Counting
instantaneous frequency can be computed directly without signal
decomposition process. The intrinsic mode functions obtained through
empirical mode decomposition belongs to simple wave. So
-Counting instantaneous frequency can be used together with
empirical mode decomposition.
Abstract: The number of users supported in a DS-CDMA
cellular system is typically less than spreading factor (N), and the
system is said to be underloaded. Overloading is a technique to
accommodate more number of users than the spreading factor N. In
O/O overloading scheme, the first set is assigned to the N
synchronous users and the second set is assigned to the additional
synchronous users. An iterative multistage soft decision interference
cancellation (SDIC) receiver is used to remove high level of
interference between the two sets. Performance is evaluated in terms
of the maximum number acceptable users so that the system
performance is degraded slightly compared to the single user
performance at a specified BER. In this paper, the capacity of CDMA
based O/O overloading scheme is evaluated with SDIC receiver. It is
observed that O/O scheme using orthogonal Gold codes provides
25% channel overloading (N=64) for synchronous DS-CDMA
system on an AWGN channel in the uplink at a BER of 1e-5.For a
Rayleigh faded channel, the critical capacity is 40% at a BER of 5e-5
assuming synchronous users. But in practical systems, perfect chip
timing is very difficult to maintain in the uplink.. We have shown that
the overloading performance reduces to 11% for a timing
synchronization error of 0.02Tc for a BER of 1e-5.
Abstract: Most fingerprint recognition techniques are based on minutiae matching and have been well studied. However, this technology still suffers from problems associated with the handling of poor quality impressions. One problem besetting fingerprint matching is distortion. Distortion changes both geometric position and orientation, and leads to difficulties in establishing a match among multiple impressions acquired from the same finger tip. Marking all the minutiae accurately as well as rejecting false minutiae is another issue still under research. Our work has combined many methods to build a minutia extractor and a minutia matcher. The combination of multiple methods comes from a wide investigation into research papers. Also some novel changes like segmentation using Morphological operations, improved thinning, false minutiae removal methods, minutia marking with special considering the triple branch counting, minutia unification by decomposing a branch into three terminations, and matching in the unified x-y coordinate system after a two-step transformation are used in the work.
Abstract: This research aims to study value-creation process of
producing monk-s bowls, Thai traditional handicrafts, which is facing problems in adapting to the changing society. It also aims to identify
problems and obstacles to value creation. This research is based on a case study of monk-s bowl manufactures from Ban-Baat Village,
Bangkok. The conceptual framework is based on the model of value
chain to analyze the process.
The research methodology is qualitative. This research found that the value-creation process of monk-s bowls consists of eight
activities contributing to adding value to the products and increasing
profits to the producers in return. Five major problems and obstacles
are found.
The research suggests that these problems and obstacles limit the manufacturers- potential for creating more valued product and lead to business stagnation. These problems should be addressed and solved with collaboration among the government, the private sector and the
manufacturers.
Abstract: In this study, a mathematical model was proposed and
the accuracy of this model was assessed to predict the growth of
Pseudomonas aeruginosa and rhamnolipid production under nitrogen
limiting (sodium nitrate) fed-batch fermentation. All of the
parameters used in this model were achieved individually without
using any data from the literature.
The overall growth kinetic of the strain was evaluated using a
dual-parallel substrate Monod equation which was described by
several batch experimental data. Fed-batch data under different
glycerol (as the sole carbon source, C/N=10) concentrations and feed
flow rates were used to describe the proposed fed-batch model and
other parameters. In order to verify the accuracy of the proposed
model several verification experiments were performed in a vast
range of initial glycerol concentrations. While the results showed an
acceptable prediction for rhamnolipid production (less than 10%
error), in case of biomass prediction the errors were less than 23%. It
was also found that the rhamnolipid production by P. aeruginosa was
more sensitive at low glycerol concentrations.
Based on the findings of this work, it was concluded that the
proposed model could effectively be employed for rhamnolipid
production by this strain under fed-batch fermentation on up to 80 g l-
1 glycerol.
Abstract: Control of commutation of switched reluctance (SR)
motor has been an area of interest for researchers for sometime now
with mixed successes in addressing the inherent challenges. New
technologies, processing schemes and methods have been adopted to
make sensorless SR drive a reality. There are a number of
conceptual, offline, analytical and online solutions in literature that
have varying complexities and achieved equally varying degree of
robustness and accuracies depending on the method used to address
the challenges and the SR drive application. Magnetic coupling is
one such challenge when using active probing techniques to
determine rotor position of a SR motor from stator winding. This
paper studies the effect of back-of-core saturation on the detected
rotor position and presents results on measurement made on a 4-
phase SR motor. The results shows that even for a four phase motor
which is excited one phase at a time and using the electrically
opposite phase for active position probing, the back-of-core
saturation effects should not be ignored.
Abstract: Although e-mail is the most efficient and popular communication method, unwanted and mass unsolicited e-mails, also called spam mail, endanger the existence of the mail system. This paper proposes a new algorithm called Dynamic Weighted Majority Concept Drift Detection (DWM-CDD) for content-based filtering. The design purposes of DWM-CDD are first to accurate the performance of the previously proposed algorithms, and second to speed up the time to construct the model. The results show that DWM-CDD can detect both sudden and gradual changes quickly and accurately. Moreover, the time needed for model construction is less than previously proposed algorithms.