Abstract: Research on damage of gears and gear pairs using
vibration signals remains very attractive, because vibration signals
from a gear pair are complex in nature and not easy to interpret.
Predicting gear pair defects by analyzing changes in vibration signal
of gears pairs in operation is a very reliable method. Therefore, a
suitable vibration signal processing technique is necessary to extract
defect information generally obscured by the noise from dynamic
factors of other gear pairs.This article presents the value of cepstrum
analysis in vehicle gearbox fault diagnosis. Cepstrum represents the
overall power content of a whole family of harmonics and sidebands
when more than one family of sidebands is present at the same time.
The concept for the measurement and analysis involved in using the
technique are briefly outlined. Cepstrum analysis is used for detection
of an artificial pitting defect in a vehicle gearbox loaded with
different speeds and torques. The test stand is equipped with three
dynamometers; the input dynamometer serves asthe internal
combustion engine, the output dynamometers introduce the load on
the flanges of the output joint shafts. The pitting defect is
manufactured on the tooth side of a gear of the fifth speed on the
secondary shaft. Also, a method for fault diagnosis of gear faults is
presented based on order Cepstrum. The procedure is illustrated with
the experimental vibration data of the vehicle gearbox. The results
show the effectiveness of Cepstrum analysis in detection and
diagnosis of the gear condition.
Abstract: In 3D-wavelet video coding framework temporal
filtering is done along the trajectory of motion using Motion
Compensated Temporal Filtering (MCTF). Hence computationally
efficient motion estimation technique is the need of MCTF. In this
paper a predictive technique is proposed in order to reduce the
computational complexity of the MCTF framework, by exploiting
the high correlation among the frames in a Group Of Picture (GOP).
The proposed technique applies coarse and fine searches of any fast
block based motion estimation, only to the first pair of frames in a
GOP. The generated motion vectors are supplied to the next
consecutive frames, even to subsequent temporal levels and only fine
search is carried out around those predicted motion vectors. Hence
coarse search is skipped for all the motion estimation in a GOP
except for the first pair of frames. The technique has been tested for
different fast block based motion estimation algorithms over different
standard test sequences using MC-EZBC, a state-of-the-art scalable
video coder. The simulation result reveals substantial reduction (i.e.
20.75% to 38.24%) in the number of search points during motion
estimation, without compromising the quality of the reconstructed
video compared to non-predictive techniques. Since the motion
vectors of all the pair of frames in a GOP except the first pair will
have value ±1 around the motion vectors of the previous pair of
frames, the number of bits required for motion vectors is also
reduced by 50%.
Abstract: The incidence of mechanical fracture of an
automobile piston rings prompted development of fracture analysis
method on this case. The three rings (two compression rings and one
oil ring) were smashed into several parts during the power-test (after
manufacturing the engine) causing piston and liner to be damaged.
The radial and oblique cracking happened on the failed piston rings.
The aim of the fracture mechanics simulations presented in this paper
was the calculation of particular effective fracture mechanics
parameters, such as J-integrals and stress intensity factors. Crack
propagation angles were calculated as well. Two-dimensional
fracture analysis of the first compression ring has been developed in
this paper using ABAQUS CAE6.5-1 software. Moreover, SEM
fractography was developed on fracture surfaces and is discussed in
this paper. Results of numerical calculations constitute the basis for
further research on real object.
Abstract: This study was to investigate the performance of
hybrid solvents blended between primary, secondary, or tertiary
amines and piperazine (PZ) for CO2 removal from flue gas in terms
of CO2 absorption capacity and regeneration efficiency at 90 oC.
Alkanolamines used in this work were monoethanolamine (MEA),
diethanolamine (DEA), and triethanolamine (TEA). The CO2
absorption was experimentally examined under atmospheric pressure
and room temperature. The results show that MEA blend with PZ
provided the maximum CO2 absorption capacity of 0.50 mol
CO2/mol amine while TEA provided the minimum CO2 absorption
capacity of 0.30 mol CO2/mol amine. TEA was easier to regenerate
for both first cycle and second cycle with less loss of absorption
capacity. The regeneration efficiency of TEA was 95.09 and 92.89 %,
for the first and second generation cycles, respectively.
Abstract: Self-directed learning (SDL) was developed initially
for adult learning. Guglielmino constructed a scale to measure SDL.
Recent researchers have applied this concept to children. Although
there are sufficient theoretical evidences to present the possibility of
applying this concept to children, empirical evidences were not
provided. This study aimed to examine the quality of SDL and
construct a scale to measure SDL among young children. A modified
scale of Guglielmino-s scale was constructed and piloted with 183
subjects of age 9. Findings suggest that the qualities of SDL in young
ages are apparently congruent with that of adults.
Abstract: Researches related to standard product model and
development of neutral manufacturing interfaces for numerical
control machines becomes a significant topic since the last 25 years.
In this paper, a detail description of STEP implementation on turnmill
manufacturing has been discussed. It shows requirements of
information contents from ISO14649 data model. It covers to
describe the design of STEP-NC framework applicable to turn-mill
manufacturing. In the framework, EXPRESS-G and UML modeling
tools are used to depict the information contents of the system and
established the bases of information model requirement. A product
and manufacturing data model applicable for STEP compliant
manufacturing. The next generation turn-mill operations
requirements have been represented by a UML diagram. An object
oriented classes of ISO1449 has been developed on Visual Basic dot
NET platform for binding the static information model represented
by the UML diagram. An architect of the proposed system
implementation has been given on the bases of the design and
manufacturing module of STEP-NC interface established. Finally, a
part 21 file process plan generated for an illustration of turn-mill
components.
Abstract: with increasing circuits- complexity and demand to
use portable devices, power consumption is one of the most
important parameters these days. Full adders are the basic block of
many circuits. Therefore reducing power consumption in full adders
is very important in low power circuits. One of the most powerconsuming
modules in full adders is XOR/XNOR circuit. This paper
presents two new full adders based on two new logic approaches. The
proposed logic approaches use one XOR or XNOR gate to implement
a full adder cell. Therefore, delay and power will be decreased. Using
two new approaches and two XOR and XNOR gates, two new full
adders have been implemented in this paper. Simulations are carried
out by HSPICE in 0.18μm bulk technology with 1.8V supply voltage.
The results show that the ten-transistors proposed full adder has 12%
less power consumption and is 5% faster in comparison to MB12T
full adder. 9T is more efficient in area and is 24% better than similar
10T full adder in term of power consumption. The main drawback of
the proposed circuits is output threshold loss problem.
Abstract: It is quite essential to form dialogue mechanisms and
dialogue channels to solve intercultural communication issues.
Therefore, every country should develop a intercultural education
project which aims to resolve international communication issues.
For proper mediation training, the first step is to reach an agreement
on the actors to run the project. The strongest mediation mechanisms
in the world should be analyzed and initiated within the educational
policies. A communication-based mediation model should be
developed for international mediation training. Mediators can use
their convincing communication skills as a part of this model. At the
first, fundamental stages of the mediation training should be specified
within the scope of the model. Another important topic at this point is
common sence and peace leaders to act as an ombudsman in this
process. Especially for solving some social issues and conflicts,
common sense leaders acting as an ombudsman would lead to
effective communication. In mediation training that is run by
universities and non-governmental organizations, another phase is to
focus on conducting the meetings. In intercultural mediation training,
one of the most critical topics is to conduct the meeting traffic and
performing a shuttle diplomacy. Meeting traffic is where the mediator
organizes meetings with the parties with initiative powers, in order to
contribute to the solution of the issue, and schedule these meetings.
In this notice titled “ Intercultural mediation training and the training
process of common sense leaders by the leadership of universities
communication and artistic campaigns" , communication models and
strategies about this topic will be constructed and an intercultural art
activities and perspectives will be presented.
Abstract: The malfunction of thermal protection system (TPS) caused by aerodynamic heating is a latent trouble to aircraft structure safety. Accurately predicting the structure temperature field is quite important for the TPS design of hypersonic vehicle. Since Thornton’s work in 1988, the coupled method of aerodynamic heating and heat transfer has developed rapidly. However, little attention has been paid to the influence of structural deformation on aerodynamic heating and structural temperature field. In the flight, especially the long-endurance flight, the structural deformation, caused by the aerodynamic heating and temperature rise, has a direct impact on the aerodynamic heating and structural temperature field. Thus, the coupled interaction cannot be neglected. In this paper, based on the method of static aero-thermo-elasticity, considering the influence of aero-thermo-elasticity deformation, the aerodynamic heating and heat transfer coupled results of hypersonic vehicle wing model were calculated. The results show that, for the low-curvature region, such as fuselage or center-section wing, structure deformation has little effect on temperature field. However, for the stagnation region with high curvature, the coupled effect is not negligible. Thus, it is quite important for the structure temperature prediction to take into account the effect of elastic deformation. This work has laid a solid foundation for improving the prediction accuracy of the temperature distribution of aircraft structures and the evaluation capacity of structural performance.
Abstract: In recent years, there has been an increasing interest
toward the use of bovine genotyped embryos for commercial embryo
transfer programs. Biopsy of a few cells in morulla stage is essential
for preimplantation genetic diagnosis (PGD). Low amount of DNA
have limited performing the several molecular analyses within PGD
analyses. Whole genome amplification (WGA) promises to eliminate
this problem. We evaluated the possibility and performance of an
improved primer extension preamplification (I-PEP) method with a
range of starting bovine genomic DNA from 1-8 cells into the WGA
reaction. We optimized a short and simple I-PEP (ssI-PEP) procedure
(~3h). This optimized WGA method was assessed by 6 loci specific
polymerase chain reactions (PCRs), included restriction fragments
length polymorphism (RFLP). Optimized WGA procedure possesses
enough sensitivity for molecular genetic analyses through the few
input cells. This is a new era for generating characterized bovine
embryos in preimplantation stage.
Abstract: This paper presents a new feature based dense stereo
matching algorithm to obtain the dense disparity map via dynamic
programming. After extraction of some proper features, we use some
matching constraints such as epipolar line, disparity limit, ordering
and limit of directional derivative of disparity as well. Also, a coarseto-
fine multiresolution strategy is used to decrease the search space
and therefore increase the accuracy and processing speed. The
proposed method links the detected feature points into the chains and
compares some of the feature points from different chains, to
increase the matching speed. We also employ color stereo matching
to increase the accuracy of the algorithm. Then after feature
matching, we use the dynamic programming to obtain the dense
disparity map. It differs from the classical DP methods in the stereo
vision, since it employs sparse disparity map obtained from the
feature based matching stage. The DP is also performed further on a
scan line, between any matched two feature points on that scan line.
Thus our algorithm is truly an optimization method. Our algorithm
offers a good trade off in terms of accuracy and computational
efficiency. Regarding the results of our experiments, the proposed
algorithm increases the accuracy from 20 to 70%, and reduces the
running time of the algorithm almost 70%.
Abstract: Intelligent technologies are increasingly facilitating
sustainable water management strategies in Australia. While this
innovation can present clear cost benefits to utilities through
immediate leak detection and deference of capital costs, the impact of
this technology on households is less distinct. By offering real-time
engagement and detailed end-use consumption breakdowns, there is
significant potential for demand reduction as a behavioural response
to increased information. Despite this potential, passive
implementation without well-planned residential engagement
strategies is likely to result in a lost opportunity. This paper begins
this research process by exploring the effect of smart water meters
through the lens of three behaviour change theories. The Theory of
Planned Behaviour (TPB), Belief Revision theory (BR) and Practice
Theory emphasise different variables that can potentially influence
and predict household water engagements. In acknowledging the
strengths of each theory, the nuances and complexity of household
water engagement can be recognised which can contribute to
effective planning for residential smart meter engagement strategies.
Abstract: In the other to Study of drought stress and Selenium
spraying effect on superoxide dismotase (SOD) activity of rapeseed
(Brassica napus L.) cultivars in Shahr-e-Rey region, an experiment
carried out in Split factorial design in the basis of randomized
complete blocks with 4 replications in 2006. Irrigation in two levels:
Normal irrigation and irrigation with drought stress when the soil
electrical conductivity reached to 60 as main factor and rapeseed
cultivars in 3 levels Zarfam, Okapi, Opera and selenium spraying at
the beginning of flowering stage in 3 levels: 0, 16 and 21 g/ha as sub
factor.
The results showed that the simple and interaction effect of
irrigation, selenium and cultivars on SOD activity had significant
difference. In this case Zarfam cultivar with 2010 u.mg-1 protein and
Opera with 1454 u.mg-1 protein produced maximum and minimum
amounts of SOD activitiy. Interaction effect of irrigation and variety
showed that, normal irrigation in Opera with 1115 u.mg-1 protein
and drought stress in Zarfam with 2784 u.mg-1 protein conducted to
and minimum and maximum amounts of SOD activity.
Interaction effect of irrigation, cultivar and selenium on SOD
indicated that drought stress condition and 21 gr/ha selenium
spraying in Zarfam variety with 3146 u.mg-1 protein gained to
highest activities of SOD.
Abstract: This paper describes design of a digital feedback loop
for a low switching frequency dc-dc switching converters. Low
switching frequencies were selected in this design. A look up table
for the digital PID (proportional integrator differentiator)
compensator was implemented using Altera Stratix II with built-in
ADC (analog-to-digital converter) to achieve this hardware
realization. Design guidelines are given for the PID compensator,
high frequency DPWM (digital pulse width modulator) and moving
average filter.
Abstract: White rust, caused by Albugo candida, is the most
destructive foliar diseases of persian cress, Lepidium sativum in Iran.
Application of fungicide is the most common method for the disease
control. However, regarding the problems created by synthetic
pesticides application, environmentally safe methods are needed to
replace chemical pesticides. In this study, the antifungal activity of
plant natural extracts was investigated for their ability to inhibit
zoospore release from sporangia of A. candida. The crude extract of
46 plants was obtained using methanol. The inhibitory effect of the
extracts was examined by mixing the plant extracts with a
zoosporangial suspension of A. candida (1×106 spore/ml) at three
concentrations, 250, 100 and 50 ppm. The experiments were
conducted in a completely randomized design, with three replicates.
The results of the experiment showed that three out of 46 plants
species, including, Rhus coriaria, Anagallis arvensis and Mespilus
germanica were completely inhibit zoospore release from
zoosporangia of Albugo candida at concentration of 50 ppm.
Abstract: Eutrophication of surface water is one of the most
widespread environmental problems at present. Large number of
pilgrims and tourists visit sacred artificial tank known as “Brahma
Sarover” located at Kurukshetra, India to take holy dip and perform
religious ceremonies. The sources of pollutants include impurities in
feed water, mass bathing, religious offerings and windblown
particulate matter. Studies so far have focused mainly on assessing
water quality for bathing purpose by using physico-chemical and
bacteriological parameters. No effort has been made to assess nutrient
concentration and trophic status of the tank to take more appropriate
measures for improving water quality on long term basis. In the
present study, total nitrogen, total phosphorous and chlorophyll a
measurements have been done to assess the nutrient level and trophic
status of the tank. The results show presence of high concentration of
nutrients and Chlorophyll a indicating mesotrophic and eutrophic
state of the tank. Phosphorous has been observed as limiting nutrient
in the tank water.
Abstract: There are lots of different ways to find the natural
frequencies of a rotating system. One of the most effective methods
which is used because of its precision and correctness is the
application of the transfer matrix. By use of this method the entire
continuous system is subdivided and the corresponding differential
equation can be stated in matrix form. So to analyze shaft that is this
paper issue the rotor is divided as several elements along the shaft
which each one has its own mass and moment of inertia, which this
work would create possibility of defining the named matrix. By
Choosing more elements number, the size of matrix would become
larger and as a result more accurate answers would be earned. In this
paper the dynamics of a rotor-bearing system is analyzed,
considering the gyroscopic effect. To increase the accuracy of
modeling the thickness of the disk and bearings is also taken into
account which would cause more complicated matrix to be solved.
Entering these parameters to our modeling would change the results
completely that these differences are shown in the results. As said
upper, to define transfer matrix to reach the natural frequencies of
probed system, introducing some elements would be one of the
requirements. For the boundary condition of these elements, bearings
at the end of the shaft are modeled as equivalent spring and dampers
for the discretized system. Also, continuous model is used for the
shaft in the system. By above considerations and using transfer
matrix, exact results are taken from the calculations. Results Show
that, by increasing thickness of the bearing the amplitude of vibration
would decrease, but obviously the stiffness of the shaft and the
natural frequencies of the system would accompany growth.
Consequently it is easily understood that ignoring the influences of
bearing and disk thicknesses would results not real answers.
Abstract: This paper describes a method to measure and
compensate a 4 axes ultra-precision machine tool that generates micro
patterns on the large surfaces. The grooving machine is usually used
for making a micro mold for many electrical parts such as a light guide
plate for LCD and fuel cells. The ultra precision machine tool has three
linear axes and one rotational table. Shaping is usually used to
generate micro patterns. In the case of 50 μm pitch and 25 μm height
pyramid pattern machining with a 90° wedge angle bite, one of linear
axis is used for long stroke motion for high cutting speed and other
linear axis are used for feeding. The triangular patterns can be
generated with many times of long stroke of one axis. Then 90°
rotation of work piece is needed to make pyramid patterns with
superposition of machined two triangular patterns.
To make a two dimensional positioning error, straightness of two
axes in out of plane, squareness between the each axis are important.
Positioning errors, straightness and squarness were measured by laser
interferometer system. Those were compensated and confirmed by
ISO230-6. One of difficult problem to measure the error motions is
squareness or parallelism of axis between the rotational table and
linear axis. It was investigated by simultaneous moving of rotary table
and XY axes. This compensation method is introduced in this paper.
Abstract: This study realizes an empirical investigation of main factors to develop an accounting career, stereotypes on accountants and accounting and perceptions on future career path for a sample of master students in accounting. The research provides some insight into what master students consider when choosing their future career paths. The most important two reasons chosen by students were “career opportunities" and “future earnings. They see accounting as structured, governed by conformity, requiring skills in working with numbers, monotonous, accurate, more efficient than effective but also absorbing, interesting and involving a certain degree of novelty. Although these students plan to start their careers in a multinational or accounting/audit firm, most of those plan to leave after five years. It resulted that women value more flexibility and time requiring special attention in retention policies practiced by firms.
Abstract: One of the main research directions in CAD/CAM
machining area is the reducing of machining time.
The feedrate scheduling is one of the advanced techniques that
allows keeping constant the uncut chip area and as sequel to keep
constant the main cutting force. They are two main ways for feedrate
optimization. The first consists in the cutting force monitoring, which
presumes to use complex equipment for the force measurement and
after this, to set the feedrate regarding the cutting force variation. The
second way is to optimize the feedrate by keeping constant the
material removal rate regarding the cutting conditions.
In this paper there is proposed a new approach using an extended
database that replaces the system model.
The feedrate scheduling is determined based on the identification
of the reconfigurable machine tool, and the feed value determination
regarding the uncut chip section area, the contact length between tool
and blank and also regarding the geometrical roughness.
The first stage consists in the blank and tool monitoring for the
determination of actual profiles. The next stage is the determination
of programmed tool path that allows obtaining the piece target
profile.
The graphic representation environment models the tool and blank
regions and, after this, the tool model is positioned regarding the
blank model according to the programmed tool path. For each of
these positions the geometrical roughness value, the uncut chip area
and the contact length between tool and blank are calculated. Each of
these parameters are compared with the admissible values and
according to the result the feed value is established.
We can consider that this approach has the following advantages:
in case of complex cutting processes the prediction of cutting force is
possible; there is considered the real cutting profile which has
deviations from the theoretical profile; the blank-tool contact length
limitation is possible; it is possible to correct the programmed tool
path so that the target profile can be obtained.
Applying this method, there are obtained data sets which allow the
feedrate scheduling so that the uncut chip area is constant and, as a
result, the cutting force is constant, which allows to use more
efficiently the machine tool and to obtain the reduction of machining
time.