Boards
Editorial
Preface
Contents of Number
1
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Experimental Study on
Formaldehyde Emission from Environmental Protection and
Energy-Saving Alcohol Fuel for Vehicles
Dandan Liu,
Shigang Li, Hui Liu. |
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Abstract: With the further increase of domestic oil
demand, the diversification strategy of energy supply
represented by alternative energy sources, such as alcohol fuel
which has become a direction of China's energy policy. Alcohol
fuel can reduce conventional engine emissions by replacing
conventional gasoline and diesel, but their unconventional
emissions -- formaldehyde -- tend to have higher concentrations
than conventional engines. Based on this, this paper analyzed
the physical and chemical properties of mixture of methanol and
gasoline and its feasibility as an energy fuel, and conducted
experiments on formaldehyde emission of gasoline and methanol
gasoline respectively, and then obtained a large number of
experimental data that studied and analyzed the experimental
results and methods, and drew relevant research conclusions. The
results show that the high ratio of alcohol fuel can replace the
use of chemical fuel and has good energy saving and
environmental protection characteristics. When the same fuel is
tested, the formaldehyde emission increases first and then
decreases with the increase of power. In this paper, a large
amount of formaldehyde emission data from alcohol fuel engines
are obtained through bench experiments, which provides a
scientific basis for the future development of alcohol fuel
vehicle combustion system and the formulation of environmental
emission standards.
Keywords: engine, alcohol
fuel, methanol, unconventional emission, formaldehyde;
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Design of the Lower Control Arm of an Electric SUV Front
Suspension Based on Multi-Disciplinary Optimization Technology
Zhenqi Yu, Huifang Jia, Xingyuan Huang |
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Abstract: An electric SUV is designed and developed based
on the original traditional fuel vehicle model. The design
scheme of the front suspension lower control arm of prototype
vehicle is referred to save the development cycle and cost of
the design. The original design scheme is optimized to meet the
performance and lightweight requirements. In this paper, the
analysis model of lower control arm is firstly established based
on the finite element technology to conduct free modal analysis.
The results show that the first two modes appear as bending and
torsion. The modal frequency is higher than excitation
frequency, which satisfies the requirement of vibration
characteristics. Then free modal test on lower control arm is
carried out based on hammer method, and the test results show
that the accuracy of the analysis value is high. Then, the front
suspension dynamics model of electric SUV model is established
to extract the load of lower control arm. The inertial release
method is applied to analyze its limit strength, the results
show that its maximum stress is lower than its used stress which
meets the requirements of strength design. Finally, the
multidisciplinary optimal design of lower control arm is carried
out to obtain the best design scheme. After optimization, both
modal characteristics and strength characteristics meet the
design requirements, and its mass is reduced by 16.7%. And its
optimization scheme has passed the bench test and road test
certificate successfully, so it has high accuracy and
feasibility, providing a new idea for the design and development
of the lower control arm, the front suspension of electric SUV.
Keywords:lower control arm;
modal; inertia release; strength; optimization; bench test;
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Accurate Modeling and Numerical Control Machining for Spiral
Rotor of Double Rotor Flowmeter
Chunyan Tian, Hai Jiang, Chaochao Chen |
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Abstract: Aiming at the design and manufacturing problems
of the spiral rotor of dual-rotor flowmeter, the profile
characteristics and forming principles of the spiral rotor are
analyzed, and the function equation of its cross-section profile
curve is derived. Based on the analysis, a mathematical model
for machining screw rotor with spherical milling cutter is
established and the accurate three-dimensional modeling of
spiral rotor parts is realized by using UG software. The
simulation of the two rotors proves that the modeling method is
reasonable and effective. Then using automatic programming and
manual programming methods, a multi-axis NC machining program
for the parts is written. The macro variable is introduced for
the main program to call many times, which greatly simplifies
the program structure, reduces the amount of program, and is
easy to modify. The NC machining experiment of the spiral rotor
with a standard ball-end milling cutter on a four-axis milling
machining center is conducted. The results show that the screw
rotor machined by the mathematical model has good quality. This
programming and manufacturing method is very suitable for
processing spiral rotors in multi-variety small batch
production, and thus a high machining accuracy can be achieved.
Keywords:spiral rotor;
functional equation; digital modeling; NC programming;
multi-axis simultaneous machining;
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Simulation Analysis of the Effects of EGR Rate on HCCI
Combustion of Free-piston Diesel Engine Generator
Chunhui Liu, Kechuan Yi |
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Abstract: The effects of exhaust gas recirculation (EGR)
rate on homogeneous charge compression ignition (HCCI)
combustion and emission of free-piston diesel engine generator (FPDEG)
was investigated by using a three-dimensional (3-D)
computational fluid dynamics (CFD) model of FPDEG. In the 3-D
CFD model of FPDEG, the diesel mechanism with 109 species and
543 reactions was incorporated into the combustion model, and
the soot and NOx production were calculated by Hiroyasu-NSC
model and 12 steps NOx model. The simulation results showed that
the EGR rate had great influence on the HCCI combustion and
emission performance of FPDEG. As the EGR rate was changed from
0 to 10%, the HCCI combustion phase of FPDEG slightly lagged,
the peak value of heat release, the maximum in-cylinder
temperature and pressure and the NOx content significantly
decreased, but SOOT content increased. When the EGR rate was
20%, the HCCI combustion of FPDEG was incomplete, and the UCH,
SOOT and CO content all obviously increased.
Keywords:Free-piston diesel
engine generator, Homogeneous charge compression ignition,
diesel mechanism, exhaust gas recirculation;
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Space Trajectory Planning of Electric Robot Based on Unscented
Kalman Filter
Chang Kuang, Xiaoyi Zheng |
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Abstract: Abstract: The effects of exhaust gas
recirculation (EGR) rate on homogeneous charge compression
ignition (HCCI) combustion and emission of free-piston diesel
engine generator (FPDEG) was investigated by using a
three-dimensional (3-D) computational fluid dynamics (CFD) model
of FPDEG. In the 3-D CFD model of FPDEG, the diesel mechanism
with 109 species and 543 reactions was incorporated into the
combustion model, and the soot and NOx production were
calculated by Hiroyasu-NSC model and 12 steps NOx model. The
simulation results showed that the EGR rate had great influence
on the HCCI combustion and emission performance of FPDEG. As the
EGR rate was changed from 0 to 10%, the HCCI combustion phase of
FPDEG slightly lagged, the peak value of heat release, the
maximum in-cylinder temperature and pressure and the NOx content
significantly decreased, but SOOT content increased. When the
EGR rate was 20%, the HCCI combustion of FPDEG was incomplete,
and the UCH, SOOT and CO content all obviously increased.
Keywords:Free-piston diesel engine generator, Homogeneous charge
compression ignition, diesel mechanism, exhaust gas
recirculation;
Keywords:Kalman filter;
Electric robot; Space track; Mobile trajectory planning;
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The
Electric Vehicle Torque Adaptive Drive Anti-Skid Control Based
on Objective Optimization
Yingqi He |
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Abstract: The vehicle is interfered by the lateral wind
in the traditional anti-skid control method, which results in a
bad anti-skid control effect of electric vehicle torque drive.
For this reason, a method of torque adaptive drive anti-skid
control for electric vehicle is proposed. In order to realize
the driving force control of distributed driving electric
vehicle, the driving motor is modeled and simplified. A battery
model was established to analyze the influence of the bus
voltage fluctuation on the motor torque response. The power
system model is added to the existing vehicle model to complete
the simulation model design of the distributed drive electric
vehicle. According to the characteristics of the friction circle
of the tire, the driving torque of the driving wheel is
analyzed. In order to resist the influence of interference
factors on vehicles during vehicle movement, through the concept
of vehicle stability control, the left and right driving torque
is dynamically adjusted by using the obtained ideal driving
force distribution ratio of front and rear axles. The simulation
results show that the proposed method can effectively increase
the driving torque and improve the fitting coefficient of the
driving anti-skid torque.
Keywords:Distributed drive;
Drive skid control; Driving force distribution; Dynamical system
modeling;
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The
Role of Double-Cylinder Insulation Technology in Ensuring the
Quality of Bored Pile Concrete under Negative Temperature
Condition
Ziying Liua, Tianlai Yu, Ning Yan, Zhihai Piao, Hongxiang
Zhang |
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Abstract: In this paper, the cement concrete with low
heat of hydration was prepared by adding fly ash, and then used
in the double-cylinder insulation technology. Based on heat
dissipation test, thermal conductivity test and low temperature
strength test of the prepared concrete, the growth law of
concrete strength under negative temperature condition was
studied. The strengths of three concrete test piles at the
corresponding temperature were measured by ultrasonic method,
and the influence law of double-cylinder insulation technology
on the change of concrete strength was studied. The results show
that the curing temperature dropped from 20C to -3C, -5C and
-7C on the 28th day. Compared with the standard curing
temperature, the strength loss was 29.7%, 31.7% and 42.8%,
respectively. There were similar rules on the 60th day and 28th
day. In the first 7 days, the temperature of low hydration heat
concrete was 1. ~2.8°C lower than that of ordinary concrete.
From the 7th day to the 28th day, the temperature of low
hydration heat concrete was 0.5°C higher than that of ordinary
concrete. After applying the double-cylinder insulation
technology to the concrete, the temperature was increased by
7.9°C, 7.3°C and 4.8°C in 0~3rd day, 3rd~7th day and 7th~28th
day, respectively. Compared with strength on the 28th day, the
strength of low-hydration heat concrete was 2.15% higher than
that of ordinary concrete. After applying polyurethane
insulation layer, the strength of the low-hydration heat
concrete increased by 18.6% compared with that of the
low-hydration heat concrete without insulation layer.
Keywords:negative temperature, concrete, low heat of
hydration, heat preservation, temperature of foundation pile,
strength; |
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Wear Properties of Aluminum Alloy 211z.1 Drilling Tool
Yong Liu, Lin He, Sen Yuan |
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Abstract: In the application process of China’s
independently produced new aluminum alloy 211z.1 into high-end
military and civilian industries, a great many holes are needed
for fastening connection. However, the severe wear of the
cutting edge of twist drill is an important factor that
restricts the quality of hole processing and tool life. In this
paper, the wear condition of the standard high-speed steel twist
drill in drilling the new aluminum alloy 211z.1 is studied based
on the drilling test, and the influence law of the drilling
amount on the tool wear is revealed by designing a reasonable
drilling test plan. The research results show that the cutting
speed has a significant effect on the flank wear, and the
drilling feed and the drilling height have relatively little
influence on the flank wear of the tool.
Keywords:Aluminum Alloy
211z.1; High-speed Steel; Standard Twist Drill; Drilling Test;
Flank Wear; |
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Calculation Method of Stiffness and Deflection of Corroded RC
Beam Strengthened by Steel Plate
Qian Zhang, Huang Tang, Shihui Guo |
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Abstract: Abstract: In the application process of China’s
independently produced new aluminum alloy 211z.1 into high-end
military and civilian industries, a great many holes are needed
for fastening connection. However, the severe wear of the
cutting edge of twist drill is an important factor that
restricts the quality of hole processing and tool life. In this
paper, the wear condition of the standard high-speed steel twist
drill in drilling the new aluminum alloy 211z.1 is studied based
on the drilling test, and the influence law of the drilling
amount on the tool wear is revealed by designing a reasonable
drilling test plan. The research results show that the cutting
speed has a significant effect on the flank wear, and the
drilling feed and the drilling height have relatively little
influence on the flank wear of the tool.
Keywords:Steel Plate, Corroded RC Beam, Strengthening,
Stiffness, Deflection, Calculation Method.; |
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Electromechanical Coupling Model of AC Asynchronous Motor Drive
System Based on Multiscale Method
Qiuping Pan, Jiaxiang Zhang |
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Abstract: Due to the development of motor drive system
towards high power, integration and high-power density, this
model cannot control mechanical vibration caused by
electromechanical coupling. A new electromechanical coupling
model of alternating current (AC) induction motor drive system
is proposed. The transient characteristics of the motor were
studied by multi-scale method, and the electromechanical
coupling dynamic characteristics of the drive system were
extracted. According to the dynamometer, the impact load is
applied to the drive system, which causes the load on the
inertial flywheel to suddenly increase by 3.5 times from 2500
Nm. The service coefficient of the realization shaft is defined
as the ratio of the measured post-impact torque to the average
pre-impact torque. The experimental results show that when the
AC asynchronous motor's influence is passed through the
electromechanical coupling model, the difference between the
input and output shafts of the gearbox is minimal, and when the
AC asynchronous motor's influence is different, the input and
output shafts of the gearbox are maximum. It can be seen that
the electromechanical coupling model established in this paper
can control the mechanical vibration caused by electromechanical
coupling and convert the internal load threat to the external
load threat
Keywords:multiscale method; AC asynchronous motor; drive
system; electromechanical coupling model; |
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Impact Evaluation of Industrial Energy Consumption Based on
Input-output Complex Network
Ren Zhou, Xinhua Wang |
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Abstract:
Target control and industrial transfer are important methods to
regulate energy conservation and emission reduction in the
region, so measuring the influence of each industry to energy
consumption is the basis of regional industrial structure
adjustment. Firstly, an energy flow network model is constructed
based on the theory of Industrial Complex Network. It describes
the mutual input and consumption of material and energy among
industrial sectors. Then, the index system is designed to
evaluate the influence of each industry on energy consumption in
the economic system. According to the evaluation, methods are
searched for to regulate energy-saving and emission-reducing on
the industrial level. Based on the data of Shandong Province,
the strategies of energy saving and emission reduction are put
forward: research and develop new technologies; Sort management,
focusing on the control of “key industries”, and paying
attention to the industries that consume less energy but
relevant more with others appropriately; Rational layout
industry, optimize industrial structure and so on.
Keywords:energy consumption; energy flow network;
Shandong province; evaluation of industrial impact;
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A
New Method to Analyze CNC Lathe Faults Based on
Gutenberg–Richter Curve
Jie Yu, Zhiwei Zhu, Tiebin Wang, Yue Yao, Jiexiang Ding |
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Abstract:
This paper collects and sorts out a large amount of fault data
of a series of CNC lathes, and analyzes the fault data to
classify fault levels. The values of a and b are obtained by
Gutenberg–Richter (G-R) curve fitting, and then the relationship
between a and b is used. The b value under each division
criterion is obtained. By analyzing and comparing these b
values, the rationality of classifying the fault levels
according to these three methods is verified. The b-value is
towards 1.0 when the reliability level of CNC lathes was
promoted through ten years' reliability promotion.
Keywords: Gutenberg–Richter (G-R) curve; b value; CNC machine
tool; fault level; reliability;
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Analysis of Activity Parameters of CNC Machine Tools Failures
Based on Gutenberg–Richter Curve
Jie Yu, Zhiwei Zhu, Tiebin Wang, Yue Yao, Jiexiang Ding |
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Abstract:
Gutenberg–Richter (G-R) scaling relations are commonly used on
seism prediction. The variance of b-values can reflect the seism
active degree of the area. B value in frequent failure time is
lower than in stable failure time. We use the curve to calculate
the values of parameters a and b in the Gutenberg–Richter (G-R)
relation, draw a graph of the b-value and the ratio of the
number of failures over time, and find that the trend is
reversed, which prove that the b-value can reflect the ratio of
the number of failures. Draw the trend curve of a-value and lgN.
By comparing and finding the same trend, it is proved that the
a-value can reflect the overall level of failure data. The
relationship between a and b-value is analyzed and the
influencing factors on activity parameters are discussed.
Keywords: CNC machine tool, Gutenberg–Richter (G-R) curve,
a-value, b-value, Gutenberg–Richter (G-R) scaling relation;
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Fault Status Information Monitoring Technology for Large Complex
Electromechanical System
Baoli Wei, Hongtao Jiao |
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Abstract:
In order to improve the accuracy of fault state monitoring of
electromechanical system, a fault state informatization
monitoring technology for large complex electromechanical system
is proposed. Based on the standard PD (Partial Discharge) signal
expression derived from the traditional communication theory,
the characteristic value of the fault signal is calculated, and
the feature of the fault state signal is extracted by using the
functions of the time and frequency of the fault state of the
electromechanical system. Experimental results show that
compared with the information monitoring technology based on
support vector machine, the proposed fault monitoring technology
has a higher monitoring accuracy.
Keywords: complex electromechanical; system fault state;
informatization; monitoring technology;
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Method of Power Performance Fault Alarm of Hybrid Electric
Vehicle Based on Hydraulic Technology
Wenjuan Liu |
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Abstract:
Due to the lack of precision in the modeling of the vehicle
power system, the fault diagnosis and alarm accuracy of the
current hybrid vehicle dynamic performance fault alarm method is
reduced. Therefore, a hybrid vehicle dynamic performance fault
alarm method based on hydraulic technology is designed. The
power system model of hybrid electric vehicle is built by
hydraulic technology, which is the data base of fault diagnosis.
The method of self-diagnosis and the knowledge base of fault
diagnosis are used to realize the fault diagnosis of vehicle
power system. The interface between mobile network and on-board
information is selected to realize vehicle fault alarm by
setting alarm information content. The fault diagnosis accuracy
of this method is always between 88.5% and 94.5%, the fault
diagnosis time is less than 0.5 s, and the highest effective
failure alarm rate is 99.8%. The experimental results show that
the research method has the advantages of high accuracy, short
diagnosis time, high effective alarm rate, low cost, superior
economic performance and good application effect.
Keywords: hydraulic technology; hybrid vehicle; fault
diagnosis; fault early warning; power system modeling; mobile
network;
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Mould Pollution Control Model of Aluminum Alloy Equipment
Considering Ultraviolet Radiation Intensity
Wenbo Yang, Gang Li |
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Abstract:
Due to the particularity of the aluminum alloy equipment
material, it is extremely susceptible to mold corrosion and
corrosion in the case of external environmental pollution,
affecting the performance of the equipment. Taking the aluminum
alloy equipment contaminated by mold as the research object, the
control model of mold contamination was constructed under
different ultraviolet irradiation intensity. This includes
separating and purifying from corrosion samples of aluminum
alloy, and obtaining test culture strains, measuring the change
of pH value in the corrosion medium, and then studying the
growth characteristics of Aspergillus niger in pure Chagas
medium. Through electrochemical testing and surface morphology
analysis, the growth and corrosion behavior of mold on the
surface of aluminum alloy were studied. It is essential to
change the irradiation intensity and irradiation time of
ultraviolet ray to study its control effect on aluminum alloy
mold corrosion. The experimental results show that the
sterilization effect is the most effective and economical when
the UV intensity is 84000 μW/cm2 and the irradiation time is 30
min.
Keywords:Ultraviolet radiation intensity; aluminum alloy
equipment; mold contamination; control model; corrosion
behavior;
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Fault Tolerant Control Method of Power System of Tram Based on
PLC
Zhenzhen You |
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Abstract:
Due to the large fault classification granularity of tram power
system, there is still a problem that the gain coefficient is
not reasonable in different control links, so a fault-tolerant
control method of tram power system based on PLC is designed.
First, the fault classification of the tram power system is
carried out, then the fault diagnosis of the tram power system
is carried out. Finally, the fault-tolerant control of the tram
power system is carried out through the angle fault-tolerant
control unit, PID control algorithm model and brake pull
fault-tolerant control unit, as to complete the fault-tolerant
control of the tram power system based on PLC. The experimental
results show that the reasonable value of proportional gain
coefficient, integral gain coefficient and differential gain
coefficient are 30.00, 15.00 and 29.98 respectively.
Keywords:PLC; tram; Power system; Fault-tolerant control;
Fault diagnosis;
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Design of Mechanical and Electrical Control System of Mixed
Liquid Gas Pressure Energy Storage Based on Maximum Power Point
Tracking
Jia Zhang |
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Abstract:
In order to solve the problem that the accuracy of the
controller of the traditional mechanical control system is not
high and the efficiency of the control system is too low, a
mechanical control system based on maximum power point tracking
is designed. Through the controller platform, the embedded
microprocessor with arm architecture is used to design the basic
peripheral circuit, and to improve the control accuracy of the
controller, and to complete the hardware design of the system.
According to the characteristics of the compression efficiency
of the liquid pump, the energy storage device is modeled, the
maximum power point tracking algorithm is used to control the
speed of the motor, and the software design of the system is
completed. Regarding the hardware and software design of the
system, the mechanical and electrical control system design of
the mixed liquid gas pressure energy storage device is realized.
The experimental results show that the design system is
basically consistent with the standard control value, the system
efficiency is the largest, and the mechanical and electrical
control accuracy of the mixed oil and gas energy storage is
improved, and the active power can reach a stable state.
Keywords:Maximum power point tracking; Mixed liquid gas
pressure energy storage machine; Control system; Efficiency
value;
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Contents of Number2
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Optimal Quay Crane
Assignment and Scheduling in Port’s Container Terminals
Abbas Al-Refaie, Hala Abedalqader. |
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Abstract: Effective scheduling of quay cranes can
increase throughput, and lead to higher revenues of container
terminals. This research, therefore, proposes an optimization
model to deal with quay crane assignment and scheduling problem
(QCASP) considering multiple objective functions. The first
objective minimizes the handling makespan in the terminal by
sequencing the work of quay cranes on vessels' bays, while the
second objective aims to maximize the number of containers being
handled by each quay crane (QC) for all QCs in the container
port to make sure that all QCs are utilized during the handling
process. Finally, the third objective seeks to maximize
satisfaction levels on handling completion times. The model
takes into consideration the non-violence of non-crossing
constraints and task completion without preemption constraints.
Illustrations of the developed model were provided. The results
showed that the proposed optimization model is found effective
in optimizing terminal performance by optimizing the three
stated objective functions concurrently. In practice, solving
the QCASP helps in enhancing utilization of QCs, shortening
service period at the terminal, and increasing the throughput at
the terminal. In conclusion, the proposed optimization model can
benefit planning engineers in determining optimal quay crane
assignment and scheduling. Future research will focus on
integrating berth allocation problem with QCASP.
Keywords: Optimization, Quay
cranes, Scheduling and Assignment;
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A Rough
Multi-Attributive Border Approximation Area Comparison Approach
for Arc Welding Robot Selection
Subham Agarwal, Santonab Chakraborty, Kanika Prasad, Shankar
Chakraborty |
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Abstract: In the present day, automated industries, such
as arc welding robots have found immense applications in
manufacturing of steel furniture, automobile components,
agricultural machineries etc. Selection of the most appropriate
robot for a specific welding application can be treated as a
multi-criteria decision making problem where the best
alternative needs to be identified with respect to a set of
conflicting evaluation criteria. In this paper, rough numbers
are integrated with multi-attributive border approximation area
comparison (MABAC) approach for solving an arc welding robot
selection problem. The opinions of five decision makers are
aggregated together using rough numbers to avoid subjectivity in
the decision making process, while MABAC method is employed to
rank the candidate alternatives and choose the best robot for
the given welding application. The criteria weights are
determined using rough entropy method, which reveals that
welding performance and payload are the two most important arc
welding robot selection criteria, followed by cost of the robot.
The application of rough-MABAC method identifies robot A6 as the
most suitable choice and robot A2 as the least preferred option.
Keywords:Arc welding robot;
MABAC method; Rank; Rough set theory; Selection;
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Lead-Free Solder
Reliability Modeling Using Adaptive Neuro-Fuzzy Inference System
(ANFIS)
Azmi Alazzam, Tariq Tashtoush |
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Abstract: Lead-free solder is a new material that has
been utilized in manufacturing electronic components and
packages; therefore, the material behavior had not been analyzed
completely. This paper summarizes our effort to model the change
in lead-free solder hardness behavior with respect to aging time
and temperature as a measure of the components’ reliability.
ANFIS is a modeling technique that had been used in analyzing
the current trend and predicting future progression. The ANFIS
model was developed based on the BPN-ANN structure with two
inputs and one output using Matlab®. The developed model was
compared to different regression models that are being used
frequently in the literature. The well-trained ANFIS model gave
very accurate results for predicting the hardness (output) with
a small Root Mean Square Error (RMSE) compared to the Minitab®
regression models. ANFIS is one of the best techniques in
modeling non-linear data, and it can give better and more
accurate data representation and future prediction.
Keywords:Fuzzy Logic, Neural
Network, Behavior Modeling, Lead-Free Solder, Aging,
Reliability, Electronic packages, Matlab, Minitab;
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Numerical
Investigation of the Cooling Performance of PCM-based Heat Sinks
Integrated with Metal Foam Insertion
Ahmad K. AL-Migdady, Ali M. Jawarneh, Amer Khalil Ababneh,
Hussein N. Dalgamoni |
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Abstract: In this study, numerical simulations were
carried out to analyze the cooling behavior of PCM-based heat
sinks integrated with Aluminum foam. The performance of the PCM
based heat sink is investigated under various operating
parameters including: metal foam porosity (ε =100%, 97% and
90%), Two different PCMs (RT35HC and RT44HC) and three different
values of convective heat transfer coefficient (10, 20, 30
W/m2.K) while keeping the heat flux input constant at 3200 W/m2.
Better cooling characteristics were achieved in the heat sink
filled with RT35HC when compared to RT44HC based heat sink. The
Aluminum foam insertion further decreased the base temperature
by almost (6 and 5)°C for the (ε =97% and 90%) respectively when
compared to the no-metal foam case (ε =100%). likewise, in the
RT44HC based heat sink, a further decrease in the base
temperature by almost (5 and 4)°C was reported for the (ε =97%
and 90%) cases respectively when compared to the no-metal foam
case (ε =100%). The increase in the convective heat transfer
coefficient resulted in longer time needed for PCM melting.
Keywords: Aluminum-foam,
heat sink, Phase change material “PCM”, Electronic cooling;
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Optimization of
Performance and Exhaust Emissions of a PFI SI Engine Operated
with Iso-stoichiometric GEM Blends Using Response Surface
Methodology
Farooq Sk, D. Vinay Kumar |
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Abstract: The present work aimed at optimizing the
performance and emission characteristics of a Port Fuel
Injection (PFI) SI engine fueled with Gasoline-Ethanol-Methanol
(GEM) blends using Response Surface Methodology (RSM). Test
fuels used in the study are pure gasoline (E0), E10, E10
equivalent iso-stoichiometric GEM blend (E10_Eq), E20, E20
equivalent iso-stoichiometric GEM blend (E20_Eq). Formulated E10
and E20 equivalent blends have identical air-fuel ratios, lower
heating values, density, and octane number as target binary
blends (E10, E20). The test engine was operated with different
fuel blends by varying the engine speed from 1700 to 3300 rpm at
a constant engine load of 5 kg. For optimization of the engine,
speed and fuel blends were considered as input parameters and
brake thermal efficiency (B_The), brake specific fuel
consumption (BSFC) and, nitrogen oxide (NOx) emissions as
responses. Optimization was carried out using the desirability
approach with a target of maximizing the B_The and minimizing
the BSFC and NOx. From the results, it was observed that the
E10_Eq GEM blend operation of the test engine has optimized
values of B_The, BSFC, and NOx emissions with values of 33.17%,
251 g/kW-hr, and 1389.8 ppm respectively at an engine speed of
2416 rpm. A composite desirability value of 0.64 obtained from
the regression model shows that RSM can be conveniently employed
to determine the significant factors that could impact engine
performance and emissions;
Keywords: GEM blends,
Response surface methodology, Analysis of variance, Equivalent
blends;
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Design and
Development of a promising Biochar-based Copper Catalyst
Mohammad Hossein Nargesi, Reza Yeganeh, Fatemeh Valizadeh
kakhkib Maryam Hajjami |
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Abstract: As about 70 percent of the air pollution comes
from vehicles, automotive companies have always been seeking
novel catalytic converters to reduce engine emissions. However,
so far, a comprehensive research on the impact of copper
catalytic converters on biochar has not been conducted. This
research aims to study the effect of biochar-based catalytic
converter on the amount of exhaust emissions in an XU7 engine.
Two thicknesses of the biochar-based catalysts, 7 and 14 cm and
Cu (No3)2 in two densities of 1 and 2 mmol were applied for the
experiments. Five types of contaminants (i.e., CO, CO2, HC, O2
and NOx) were measured for the evaluation of exhaust emissions.
In this study, the XU7 engine, which was produced in 2011, was
used to perform the tests. The results showed that the levels of
exhaust gases from combustion of the XU7 engine were low and
acceptable in all treatments in comparison to the environmental
standard. In addition, the catalyst used in the XU7 engine had a
significant impact on the absorption of exhaust gas from the
engine, especially for CO and the level of its concentration was
significantly different in comparison with a new catalyst,
biochar-based catalysts and control and also, for HC the levels
of concentration were shifted applying biochar-based catalysts
comparing to the new catalyst and control. Based on the results,
it was observed that applying the proposed approach can be an
effective step in reducing greenhouse gas emissions from
combustion and increasing the life span of engines.
Keywords: XU7 Engine;
Biochar;Copper catalyst;NOx;Exhaust emissions;
|
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Comprehensive
Energy-Econo-Enviro (3E) Analysis of Grid-Connected Household
Scale Wind Turbines in Qatar
Ehsan Abbasi Teshnizi, Mehdi Jahangiri, Akbar Alidadi Shamsabadi,
Luis Martin Pomares, Ali Mostafaeipour, Mamdouh El Haj Assad |
|
Abstract: Among various types of renewables, wind energy
requires a less initial investment that is projected to decrease
even more due to technology advancement, a higher number of
turbines, and ease of restrictions. Unlike traditional
power-plants, wind turbines have been developed in various
dimensions, and minimal land is taken out of production, so they
are recommended for small countries facing a lack of space.
Given these facts, a potentio metric study of supplying the
electricity of a residential house in 5 cities of Abu Samrah,
Ar-Ruways, Doha, Duhan, and Musayid, Qatar, is performed using
HOMER and meteorological 20-year-average data taken from the
NASA website. The studied system is connected to the grid, and a
techno-Econo-environmental study is conducted. The study results
of the turbulence intensity (TI) parameter indicated the
mechanical components of the wind turbine in the Doha station
were under intermediate fatigue loads while these loads were
lower in the remaining stations. According to the results, it is
clear that Doha station, with a price per kWh of electricity
generated, and a total net present cost (NPC) of $0.086 and
$6349, respectively, produces the most cost-effective wind power
electricity due to using BWC XL.1 horizontal axis wind turbine.
The highest amount of CO2 emissions savings and most top
production of CO2 are associated with Doha (-300 kg) and Abu
Samrah (2844 kg) due to using EOLO and Turby wind turbines,
respectively. Ar-Ruways generate the highest (8890 kWh/y) and
lowest (658 kWh/y) amounts of wind power electricity and Abu
Samrah stations which are due to utilizing Generic 10 kW and
Turby wind turbines, respectively.
Keywords: Power curve; Hub height; Wind speed; National
electricity grid; Weibull function; |
|
Magnus Wind Turbine
Effect Vertical Axis Using Rotating Cylinder Blades
Khalideh Al bkoor Alrawashdeh, Nabeel.S.Gharaibeh, Abdullah A.
Alshorman, Mohamad H. Okour |
|
Abstract: The aerodynamic characteristics of a Magnus
wind turbine (MWT) with cylinder blades are evaluated by using
numerical simulation COMSOL. Yaw and lifting systems are used to
identify the features of the MWT to maximizing power output at
minimum tresses, torque and fatigue. MWT is characterized by low
efficiency of power production. Therefore, it is important to
seek effective components to improve the power performance of
MWT. The blades design in Yaw and lifting system are critical
parameters that affect MWT performance. In this study, five
suggestions were discussed to choose the best configurations of
MWT in order to promote MWT application. Performance
characteristics, such as stresses, Torque, deflection and
fatigue with suggested configurations are analyzed and compared
to identify the desirable components for this type of MWT. The
results showed that the aerodynamic characteristics of MWT in
this study will be presented as a significance guide for the
initial research and preliminary design of MWT. Based on the
suggested design configuration, the results showed that the Von
Mises stresses are low at the bottom and high at the top, and
the buckling is very high at the top but low at the bottom of
the base while the maximum value of Findley’s fatigue is for the
bottom as a result of axial stress. As for the designed shaft,
the force increases when the stress increases accordingly,
therefore, the deflection also increases. Moreover, the results
showed more specified ranges of stresses distributions on blades
and deflection ranges of decrease and increase that enable for
better design, control and power utilization of turbine.
Keywords: Magnus effect,
wind turbine, stress, deflection, torque, yaw system; |
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Contents of Number3
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Mathematical
Modelling and Correlation Between the Primary Waviness and
Roughness Profiles During Hard Turning
Mite Tomov, Bojan Prangoski, Pawel Karolczak |
|
Abstract: This paper presents a research primarily aimed
at determining the correlations between the primary profile,
waviness, and roughness profiles during hard turning, using
mathematical modeling of the primary profile (Pa), the roughness
profile (Ra) and the waviness profile (Wa). For this purpose, we
employed the Design of experiments (DOE) principles expressing
the roughness parameters models as a nonlinear function shape of
the first order of the input variables: cutting speed (v), feed
(f), depth of cut (ap) and tool nose radius (rε). The models
were done based on empirical data obtained by processing special
rings made of stee lEN C55 (AISI 1055) with hardness of 53±1 HRC,
using a CNC lathe. The obtained results are presented as
mathematical models, but also as 3D diagrams which clearly show
the change trends and their mutual relationships for the
considered parameters.
Keywords: hard turning,
surface roughness, primary profile, waviness profile, roughness
profiles, mathematical modeling;
|
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Data Envelopment
Analysis in the Presence of Correlated Evaluation Variables
Mohammad Bastani, Saeedeh Ketabi, Reza Maddahi, Roya M.Ahari |
|
Abstract: Data Envelopment Analysis (DEA) is a technique
for evaluating homogeneous Decision-Making Units (DMUs) that
consume similar inputs to produce similar outputs. An essential
principle in this method is to identify inputs and outputs; the
identified inputs (outputs) must be independent of each other.
However, in the real world, there are situations where there is
a correlation between two or more inputs (outputs), and then one
of them should be considered in the performance evaluation. This
issue can cause problems in practice. The main question, in this
case, will be that" Which of these two or more correlated
variables should be considered in evaluating DMUs?". In this
paper, a method for determining an essential variable using a
DEA model is presented. In this way, the basic models of DEA
have been integrated with the 0-1 programming to achieve the
above objective. The proposed method is then improved by using
Centralized Data Envelopment Analysis (CDEA) model, followed by
refining the performance evaluation variables. At last, the
application of the proposed method has been verified for
different examples. Results show that the proposed method
selects the appropriate variable from among the correlated
variables. Also, improving the method using a centralized
approach leads to the selection of a variable that increases the
total efficiency. The application and implementation of the
proposed method is simple and does not have computational
complexity. It also does not need experts’ judgment, so it is a
cost-effective way.
Keywords: Centralized Data
Envelopment Analysis, Correlated variables, Performance
evaluation, Filtering variables;
|
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Study of the Effect
of some Deflector's Geometry Factors on the Reduction of the
Aerodynamic Drag of the Car Model
Mohamed MAINE, Mohamed EL OUMAMI, Otmane BOUKSOUR, Boujemâa
NASSIRI |
|
Abstract: In this article, passive flow control around a
generic car model has been investigated numerically. A deflector
installed on the rear window of the Ahmed model at 25° was used
to study the aerodynamic effect. The study involves the analysis
of a set of eight two-level deflector-related factors with the
aim of assessing their effects on aerodynamic drag. The assays
were determined by establishing a Plackett-Burman screening plan
and the results are studied by JMP Pro 14 software. It was
observed that the factors (type of deflector, inlet velocity and
length’s ratio) have a significant effect on reducing
aerodynamic drag. The optimal test conditions proposed by the
Plackett-Burman plan were investigated numerically and the value
obtained was slightly higher than the value of the screening
design. It was concluded that the model of Ahmed with optimal
deflector gives the best drag reduction, compared to the model
without deflector. Installing the optimal deflector on Ahmed’s
body widens the wake area and eliminates chainstay vortex.
Keywords: Aerodynamic drag,
Generic car, Ahmed model, Deflector, Plackett-Burman plan;
|
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Performance and
Emission Characteristics of Waste Frying Oil Biodiesel Stored
Under Optimized Condition
J. Pavalavana Pandian , M. Pugazhvadivu , B. Prabu, K.
Velmurugan, V.S.K. Venkatachalapathy |
|
Abstract: Diesel engines are the most ideal prime-movers
for automobiles, railways, and marine transport to generate
power. A hasty switch to alternative fuels is crucial to meet
the diesel fuel demand as well as to safeguard the environment
from the pollution caused by the diesel fuel combustion. In
recent periods, biodiesel becomes an established possible
substitute fuel for Compression Ignition (CI) engines as it
offers numerous important advantages like bio-degradability and
renewability. It also produces comparable engine performance and
relatively lowers toxic emissions. A single cylinder, 4.4 kW
rated power CI engine was operated with biodiesel with
Pyrogallol (PY) stored at optimized storage conditions (B100 (PY)),
biodiesel stored at 4.5 months at ambient condition (B100) and
diesel fuel. The engine performance results indicate that the
brake specific fuel consumption by B100 (PY) was lower with
9.62% than that of B100 and 15.09% higher than the base line
diesel fuel. The thermal efficiency of the engine fuelled with
B100 (PY) was comparable with diesel. The engine thermal
efficiency with diesel and B100 (PY) is 31.79% and 29.53%
respectively. Further, there was no significant changes in
combustion characteristics, viz. heat release rate and gas
pressure available in cylinder between B100 (PY) and diesel
fuel. The Nitrogen Oxides (NOx) with B100 (PY) was 15.04% higher
than diesel. This is because of 10 - 11% oxygen substance
present in biodiesel. However, the NOx concentration by B100 (PY)
was 8.43% lower than B100. Similarly, the smoke density with
B100 (PY) was 9.83% and 25.72% lower than B100 and diesel fuel
respectively. The engine performance results thus showed that
waste frying oil (WFO) biodiesel has to be stored under optimum
conditions to obtain equivalent engine performance and lower
emissions.
Keywords: Biodiesel, waste
frying oil, antioxidant, pyrogallol, storage stability, diesel
engine;
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Impact of Carbon
Nano Tubes on the Performance and Emissions of a Diesel Engine
Fuelled with Pongamia Oil Biodiesel
N.Kapilan |
|
Abstract: Biodiesel is considered an immediate substitute
for the fossil diesel as the fuel properties, such as calorific
value, density, ash content and acid value are comparable to the
diesel. In India, pongamia oil has considerable potential for
the biodiesel production. The pongamia oil biodiesel has lower
volatility and slightly higher viscosity than the diesel. Hence
the pongamia oil biodiesel fuelled diesel engine results in
lower thermal efficiency as compared to the diesel. The carbon
nanotubes (CNTs) were used in this work as additive to the
pongamia oil biodiesel, to enhance the atomization and to reduce
the ignition delay of the pongamia oil biodiesel. The CNTs were
added to the pongamia oil biodiesel with different dosages and
subjected to ultrasonication for 60 min, to prepare homogenous
mixture. The engine tests were conducted on a single cylinder
diesel engine without making any modifications in the fuel
injection system. The addition of CNTs to the pongamia oil
biodiesel resulted in higher brake thermal efficiency at higher
loads between 75 to 100 % of the full load. From the engine
tests, it was observed that the CNTs improves the engine thermal
efficiency and reduces the CO, HC and smoke emissions of the
diesel engine depends upon the CNT dosage. This is due to
shorten ignition delay caused by the CNTs which improves the
combustion of the pongamia oil biodiesel. The optimum CNT dosage
of 50 mg/l results in 4% increase in thermal efficiency and
reduces the CO, HC and smoke emissions by 20.33, 25 and 12.5%
respectively at full load;
Keywords: pongamia oil,
biodiesel, alternative fuel, carbon nanotubes, engine tests;
|
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Effect of Gable Roof
Angle on Natural Ventilation for an Isolated Building
Lip Kean Moey, Man Fai Kong, Vin Cent Tai, Tze Fong Go, Nor
Mariah Adam |
|
Abstract: Airflow characteristics around and within an
isolated gable roof building were investigated using
computational fluid dynamic with steady RANS equations. This
study focuses on the following parameters: streamline of
normalized velocity, pressure coefficient, and normalized
turbulent kinetic energy. Three different roof pitches of the
gable roof namely 15º, 25º, and 35º were considered. The
streamline shows that an increase in roof pitch results in a
corresponding increase of velocity at the window openings.
Meanwhile, the streamline velocity at the roof opening varies
across different roof angles. On the other hand, the pressure
coefficient at the windward side and interior of the building
decreases as the roof pitch becomes steeper. Variation in the
flow fields of 25º and 35º roof pitch with window and roof
opening, is relatively more apparent as compared to that of a
15º and 25º roof pitch. The turbulent kinetic energy at the
leeward side of the building also becomes larger with the
increase in roof pitch. Therefore, airflow behavior and
characteristics are significantly dependent on the roof pitch
which shows good agreement with the literatures. A higher roof
pitch of gable roof building is, therefore, preferred for better
ventilation rate.
Keywords: Natural
Ventilation, Gable Roof, CFD, Roof Pitch, Steady RANS,
Ventilation Rate;
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Dynamic Behavior of
Thin Graphite/Epoxy FRP Simply Supported Beam Under Thermal Load
Using 3-D Finite Element Modeling
Fadi Alfaqs |
|
Abstract: Composite laminated structures have attracted
much attention in recent years due to their wide range of
mechanical properties and applications. However, this study
presents an investigation of temperature impact as well as fiber
orientation effect on mid-plane transverse deflection and
interlaminar shear stress as the latter plays a crucial role in
the layers’ delamination in eight-layer laminated simply
supported Graphite/Epoxy FRP composite beam. The beam considered
is subjected to dynamic force of magnitude 1000 N concentrated
in the middle as frequency varies 5-50 Hz using 3-D finite
element modeling where different fiber orientations ([0o]8,
[0o/15o]s, [0o/30o]s, [0o/45o]s, [0o/60o]s, [0o/75o]s, and
[0o/90o]s) are considered for temperature 22, 40, and 60oC.
Furthermore, modal analyses are carried out for all fiber
orientations and temperatures considered. Results obtained via
this study show that natural frequencies’ values drop narrowly
when the temperature applied on the structure rises. Moreover,
dynamic mid-plane transverse and interfacial shear stress
increases when increasing temperature. It should be said that
comparing fiber orientations considered for every single
temperature across the frequency range, fiber orientation scheme
[0o]8 recorded minimum transverse deflection and maximum shear
stress.
Keywords: Laminated Beam; Dynamic; Modal, interlaminar
Shear stress; Finite element; |
|
Effect of Alkaline
Nitrates and Operating Temperature on the Performance of Dye
Sensitized Solar Cells
Mohamad I. Al-Widyan, Borhan A. Albiss, Mohammad S. Ali |
|
Abstract: This work sought to investigate experimentally
the applicability of an alkaline nitrate (NaNO3 and KNO3)-coated
TiO2 working electrode in a dye-sensitize solar cell (DSSC) in
enhancing the cell’s performance. A simple dipping method was
used to modify the surfaces of TiO2 films with nitrate aqueous
solutions with concentrations of 0.01M, 0.05M and 0.1M. Using
standard SEM, XRD and UV-Vis apparatus, the modified cell
performance was compared with an equivalent bare-TiO2 surface in
terms of performance at two temperature levels. It was found
that with higher alkaline concentrations, the electrode surface
was covered with smaller, denser and nicely oriented nitrate
nanoparticles, as well as superior optical performance and a
quite successful incorporation of the alkaline nitrates with
TiO2 paste. The modified DSSC consistently showed higher power
conversion efficiency. Specifically, findings indicate that the
power conversion efficiency of the modified cell increased by up
to 200% relative to its unmodified one. In addition, it was
found that the conversion efficiency using NaNO3–TiO2/ITO layer
was better compared to the KNO3–TiO2/ITO layer at all
concentrations and temperature levels considered. The highest
power conversion efficiency was recorded in the DSSC with NaNO3
(0.1)–TiO2/ITO layer at 1.029% and 0.84% at 13 oC and 40 oC,
respectively. Moreover, the findings reaffirmed the positive
effect of lower temperature on cell performance.
Keywords: Dye-sensitized
solar cells, Cell performance, Cell temperature, Electrode
modification, Alkaline nitrates, TiO2 nanoparticles; |
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Contents of Number4
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Establishing Process Capability Indices in a Sugar Manufacturing Industry – an Industrial Engineering Perspective
G.V.S.S.Sharma, P. Srinivasa Rao, B. Surendra Babu |
|
Abstract: Quality of the product is a very important
factor to any organization on which the future of the company
depends. There are many tools available to check and control the
quality of the product, and among them is the process capability
study which is highly important. This work is an attempt towards
applying the concepts of process capability principles
pertaining to discrete manufacturing into the scenario of
continuous process oriented industries. In this work, the
process capability study is carried out in a sugar processing
industry. Data pertaining to Critical-To-Quality parameters of
sugar have been collected for several sugar samples. The reasons
for the variability are identified and the necessary and
corrective actions are suggested to overcome the variations in
the sugar manufacturing process. A significant improvement is
registered in the process capability indexes of CP and CPK for
the identified Critical-To-Quality (CTQ) characteristics of
sugar turbidity and minimum aperture. An increase of 7 folds is
observed for the CPM value for the CTQ characteristic of minimum
aperture. Thus, the process capability indexes are calculated
and the capability of the process is determined based on their
values.
Keywords: Quality Assurance;
Process capability; Sugar processing; Statistical Process
Control; ANOVA analysis; Critical-To-Quality (CTQ)
characteristic;
|
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Aluminium Alloys
Nanostructures Produced by Accumulative Roll Bonding (ARB)
Yazan M.
Almaetah, khaleel N. Abushgair, Mohammad A. Hamdan |
|
Abstract: The accumulative roll-bonding process (ARB) is
one of the severe plastic deformation methods. It aims at
producing nano/ultra-fine-grained materials along with
enhancements in the mechanical properties. In this work, ARB was
performed on commercially cheap and available aluminium alloys
in Jordan`s local market; AL-2024-O and AL-1100-Oalloys. Four
bonding cycles were applied to promote grain refinement at room
temperature with no pre/post heat treatment. In ARB processes,
the thickness is reduced by 50% in each pass. A new stacking
technique has been performed at the alternate layers depending
on the friction of its scratched edges. After the production of
samples and the investigation of mechanical properties through
micro hardness test, tensile test was accomplished at room
temperature after each cycle with the aim of determining whether
ARB increases the mechanical properties of both aluminium alloys
besides identifying the instance were material experiences high
ultimate tensile strength. Information about the texture,
microstructure and average crystalline size of the samples was
obtained using SEM and XRD. The hardness test shows improvements
for AL-2024-O/1100-O for each cycle and reported 125 HV and 80
HV respectively after four rolling cycles. The highest UTS was
recorded for AL-2024-O and 1100-O on the 4th pass and reported
370 MPa and 170MPa respectively. It was also found out that the
percentage elongation decreased due to a decrease in ductility
after undergoing the ARB process. Moreover, after four rolling
cycles, the average grain size for AL-2024/1100 decreased to
39.6 nm and 59.9 nm respectively.
Keywords: Severe plastic
deformations, Accumulative roll bonding, Nanostructures,
Aluminium alloys;
|
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Simulation of
Trajectory Tracking and Motion Coordination for Heterogeneous
Multi-Robots System
Samer Mutawe,
Mohammad Hayajneh, Suleiman BaniHani, Mohammad Al Qaderi |
|
Abstract: The paper addresses developing a team of aerial
and ground robots to accomplish multi-robot system navigation
task in an accessible way. The motions of two different robotic
structures, namely quadcopter, and differential drive mobile
robots are simulated and controlled. Two-level controller has
been adopted for the multi-robot system. A low-level controller
is utilized for each robotic platform to insure its motion
stability and robustness. Then, a formulation of high-level
tracking controller is presented to allow each robot to avoid
obstacles in a dynamic environment and to organize its motion
with other flying/ground robots. The performance of the proposed
system is demonstrated in a simulation environment. A modeling
platform is adopted to construct the simulation environment,
which allows the user to easily adjust the models and controller
parameters as well as to implement different control algorithms.
In addition, the simulation environment helps in analyzing the
obtained results and performing several tasks in different
conditions. The real-time motion of multi-robot system is
monitored in the created environment that provides
three-dimensional graphical displays of the robotic platforms.
Simulation results show that the aerial and ground robots
produced trajectories individually to reach different targets.
Meanwhile, each robot in the system was able to navigate among
obstacles without colliding with other agents in the network.
Keywords: Ground robot,
Multi-robots, Path planning, Quadcopter, Trajectory tracking;
|
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Control of Wake Behind an
Unconfined Wedge Structure by Magnetohydrodynamics
JShailendra Rana, Hari B. Dura, Rajendra Shrestha |
|
Abstract: The laminar, viscous and incompressible flow of
an electrically conducting fluid across an unconfined wedge
structure in the presence of a transverse magnetic field has
been studied. Two-dimensional numerical simulations have been
performed for Reynolds number (Re) = 1-150 and Hartmann number
(Ha) = 0-10 for a fixed blockage ratio (β) = d/W = 1/30. The
magnetic induction method in magnetohydrodynamics module built
in ANSYS FLUENT solver has been employed to compute the flow
fields. Results show that the vortex shedding can be completely
eliminated if the applied magnetic field is strong enough. In
the steady flow regime, it has been found that the recirculation
length reduces with the increase in Ha. A minimal reduction in
the drag coefficient is observed with the increase in Ha as long
as unsteady flow is maintained (Ha < 7.3). However, the drag
coefficient has a tendency to significantly increase with the
increase in Ha for steady flow. Similarly, the lift amplitude
decreases with the increase in Ha indicating a diminishing
effect on the strength of vortices. A critical Hartmann number (Hacr)
of 7.3 has been found for Re = 100 at which complete suppression
of vortex shedding is observed.
Keywords:
Magnetohydrodynamics, active vortex suppression, Strouhal
number, magnetic Reynolds number, Hartmann number;
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Numerical Study of Fluid
Dynamics and Heat Transfer Characteristics for the Flow Past a
Heated Square Cylinder
Rashid Ali , Anshumaan Singh |
|
Abstract: Effects of inertia and buoyancy forces are
numerically investigated on fluid dynamics and heat transfer
characteristics for the flow past a heated square cylinder in an
unconfined flow regime. Non-dimensional number in the study
chosen are Re = 1 - 45, Ri = 0 - 1.50, α = 0o– 90o. The
orientation of the cylinder and the Prandtl number are kept
fixed as ϕ = 0oand Pr = 100. Numerical experiments in
generalized body-fitted coordinates subject to Boussinesq
approximation were conducted in the form of solution of
continuity, momentum and energy equations. The momentum and
energy equations are discretized using finite difference method.
The equations are solved by using SMAC type implicit pressure
correction scheme. The flow is noticed steady for 1 ≤ Re ≤ 30
and 0 ≤ Ri ≤ 0.50 at α = 0o, 1 ≤ Re ≤ 20 and 0 ≤ Ri ≤ 0.50at α =
45o, 1 ≤ Re ≤ 10 and 1.0 ≤ Ri ≤ 1.50 at α = 90o. Onset of
vortex-shedding is observed initially at Re = 30, α = 45o, 0 ≤
Ri ≤ 0.50, the flow becomes unsteady and periodic flow. At small
magnitudes of Reynolds number, the wake on downstream side of
cylinder is found thin, and it becomes wider at large magnitudes
of Reynolds number. It is noticed that the width of the wake
reduces in size with increasing Richardson number. Maximum mean
lift coefficient is found to occur at Re = 20, Ri = 1.5 and α =
90o, and maximum mean drag coefficient is noted at Re = 1 for
the chosen range of Richardson number and free-stream
orientations. For the whole range of Reynolds and Richardson
numbers, the front face(s) of the cylinder had more crowding of
isotherms in comparison with other faces of the cylinder. The
front face(s) of the cylinder have high rate of heat transfer as
compared to other cylinder faces. Heat transfer rate from the
cylinder is enhanced either with increase in Richardson number
or Reynolds number.
Keywords: Mixed convection,
streamline and isotherms patterns, contours of vorticity,
Nusselt number, rate of heat transfer;
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Investigation on the
Performance of Order Release Methods in a Flow Shop with
Bottlenecks
Aruna Prabhu,
Raghunandana K, Yogesh Pai P |
|
Abstract: The workload control (WLC) is a popular concept
in manufacturing planning and control, which plays a significant
role in enhancing the efficiency of manufacturing firms that
have uncertainty in meeting customer orders. Owing to changes in
several set of factors, such as processing time variations,
fluctuation in orders, and rise in quality issues etc., would
disrupt production schedules and adversely affect the shop
performance. Improvements are certainly possible by integrating
WLC policies in distinct stages of production that in turn help
to keep a steady workflow and balanced shop floor activities. In
this study, we have considered the production of a part of a
windmill that poses difficulties in production due to changes in
processing times. A production shop simulation model was
developed by considering real-time data. The model is simulated
to analyze the performance under different order release methods
at process time changes. In addition, we consider the influence
of downtime and capacity cushion at bottleneck station. The
objective of this research is to investigate the influence of
the processing time variation, downtime, and capacity cushion on
the performance of the shop floor and to evaluate the best
release method suitable in different situations.
Keywords: Workload control,
Order release methods, Work in process, Simulation;
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The Effects of Sulfur Content
on the Mechanical Properties of Nitrile Butadiene Rubber with
Different Aging Conditions
Nabeel
Alshabatat, Ahmad Abouel-Kasem |
|
Abstract: This paper aims to investigate the effects of
sulfur addition on enhancing the mechanical properties of
Nitrile Butadiene Rubber (NBR) composites. The composites were
prepared with the assistance of internal mixer and two-roll
mill, and then the speciemns were vulcanized by electrically
heated press. The NBR composites were prepared with different
sulfur contents (2, 3, 4, 5, and 7 phr). The tensile strength,
hardness, compression set, tear strength, and swelling ratio
were investigated. The experimental results showed that the
addition of sulfur to NBR composites improved their mechanical
properties. The unaged NBR composite containing 7 phr of sulfur
gives the best 20% modulus (650% improvement), and shore A
hardness (27.4% improvement). However, the unaged NBR composites
containing 4 phr of sulfur gives the minimum compression set
(i.e., 3.2%). Also, adding small amount of sulfur (less than 4
phr) increases the tear strength. The unaged NBR composite
containing 2 phr of sulfur gives the best tear strength (106%
improvement). The swelling ratio decreases significantly with
adding sulfur contents. The unaged NBR composites containing
more than or equal to 3 phr of sulfur give 0% swelling. Also,
the effects of different aging conditions were investigated. The
results showed that NBR composites which were aged in ozone and
air degraded more seriously than those aged in oil.
Keywords: Nitrile Butadiene Rubber; sulfur content;
rubber aging; mechanical properties; |
|
A Hybrid Batch-Fabrication
Decision for a Vendor–Buyer Integrated System with Multiple
Deliveries, Rework, and Machine Failures
Yuan-Shyi
Peter Chiu, Chia-Ming Lai, Tiffany Chiu, Chung-Li Chou |
|
Abstract: Transnational firms operate in turbulent and
competitive marketplaces. They continually find ways to optimize
their internal supply chains to guarantee that firms achieve
operating goals of high quality, quick response time, smooth
fabrication schedules, and timely deliveries under the reality
of limited capacity and unreliable machines/processes. This
study considers a vendor–buyer integrated batch-fabrication
problem with outsourcing, rework, machine failures, and multiple
deliveries to facilitate better decision making and assist
enterprises in increasing their competitive advantages. We
assume that a portion of a batch is outsourced in order to
reduce manufacturing uptime, and in-house production experiences
undesirable situations, such as machine failures and
nonconforming stock making. Corrective action on failures and
repair tasks of the nonconforming are undertaken in each cycle
as they occur. The finished stocks are then shipped under the
multiple-deliveries plan. We build a model to explicitly depict
the problem and determine the problem’s cost function through
formulations and derivations. The convexity of cost function and
the optimal uptime are obtained via differential calculus and a
proposed specific algorithm. Lastly, we offer a numerical
example to show our proposed model makes diverse crucial system
information, such as the individual and joint impact of
outsourcing, rework, random failures, as well as the frequency
of delivery on different features and the optimal uptime of the
problem, easily accessible, to assist enterprises in strategic
planning, management, and decision making in their practical
intra-supply-chain environments.
Keywords: Vendor-buyer
integrated system, Hybrid batch fabrication, Machine failures,
Rework, Multi-delivery; |
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Contents of Number5
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Improving Mechanical
Properties of Rice Husk and Straw Fiber Reinforced Polymer
Composite through Reinforcement Optimization
Sachin G
Ghalme |
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Abstract: The generation of lignocellulosic agriculture
waste and the residue is unavoidable, and disposal of the same
with burning or burying creates environmental issues. In recent
years the scientific community is continuously looking for
sustainable development using natural resources for development.
Rice husk (RH) and straw (RS) are already proposed as natural
fiber reinforcing materials for natural fiber reinforced polymer
composite (NFRPC). In this article, an attempt has been made to
obtain the optimized proportion of rice husk and straw
reinforcement in bio epoxy resin for the development of rice
husk and straw fiber-reinforced hybrid composite with improved
mechanical properties. The grey relational analysis (GRA)
methodology is implemented to obtain the optimized proportion of
RH and RS for maximization of tensile and flexural strength of
polymer composite simultaneously. The experimental and grey
relational analysis result presents the addition of 05 and 08
wt% of RS and RH fiber respectively in bio epoxy resin presents
rice straw and husk reinforced polymer composite with improved
tensile and flexural strength simultaneously.
Keywords: Natural fiber
reinforced polymer composite (NFRPC), rice husk (RH), rice straw
(RS), mechanical properties, grey relational analysis (GRA);
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Analytical Formula of
Positive Position Solution of 2PPa-PSS 3-Translational Parallel
Mechanism with Low Coupling-degree and its Numerical Application
Junjie Gong,
Wei Wei, Sixu Peng, Kechen Zhang |
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Abstract: Most of the parallel mechanisms (PM) with low
coupling degree cannot directly obtain the analytical expression
of the positive position solution of the PM, which makes it
difficult to carry out the follow-up research on the kinematic
accuracy analysis and trajectory planning of the PM. Based on
the topological structure theory, this paper analyzes the
position and orientation characteristic(POC), DOF and coupling
degree of 2PPa-PSS PM. Afterward, the kinematic mathematical
model of 2PPa-PSS PM is established based on the order single
open chain of kinematic modeling principle. The moving platform
of the mechanism is set as an equilateral triangle, and the
intermediate variables are solved by combining the constraints
of the two chains. The positive position solution of the PM in
analytical form is obtained. The correctness of the kinematic
model of the mechanism is verified by numerical calculation.
Then, according to the positive position solution analytical
expression, we can work out the complete workspace of the PM,
and the significant influence of the driving increment on the
attitude change of the moving platform is analyzed by using the
analysis method based on the orthogonal test. According to the
results of orthogonal experiment, the best driving range of the
mechanism is obtained.
Keywords: Positive position
solution; Parallel mechanism; Coupling degree; Workspace;
Orthogonal test;
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Application of Potential
Energy Method for Driver Seat Suspension System Using Quasi-Zero
Stiffness: A Numerical and Experimental Study
Mostafizur
Rahman, Md. Arafat Rahman |
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Abstract: To improve comfort, a quasi-zero stiffness (QZS)
drivers’ seat suspension system is designed and fabricated based
on potential energy method. At first, the mathematical model for
the seat suspension is established. Thereafter, a model of seat
suspension system with natural frequency of 2.45 Hz is
fabricated to check validity of this method. A negative
stiffness spring (NSS) is used as added system to reduce the
natural frequency to 1.78 Hz. In addition, double NSS is added
to suspension system to obtain QZS and natural frequency
observed to near about 0.84 Hz. Hence, vibration magnitude of
seat suspension is reduced to 27.3% in case of single NSS and
65.7% for double NSS compared with suspension system without NSS.
Compared with the original seat suspension system, the new
suspension system with NSS has better vibration isolation
characteristics and can electively improve drivers’ ride
comfort.
Keywords: Vibration; Natural
frequency; Transmissibility; Suspension system; Potential
energy; Quasi-zero stiffness; Stability;
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Impact of Abrasive Grit Size
and MQL Supply on the Surface Roughness in Belt Grinding of a
Case Hardened Steel
Amine Hamdi, Sidi Mohammed Merghache |
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Abstract: In automotive industries, the belt grinding
(BG) is a mechanical manufacturing process by removing material
using a tool called an abrasive belt. This technique enables
high surface quality and reproducibility of high-precision
mechanical parts to be achieved. The main objective of this
paper is to provide a detailed account of the effect of
superfinishing on the surface texture of 16MC5 casehardened
steel by the belt grinding process under the alumina abrasive
grains (Al2O3) with average sizes (60, 40, 30, 20 and 9 μm),
respectively. The surface quality was characterized by one
surface roughness parameter (Ra) and three parameters of the
Abbott-Firestone curve (Rpk, Rk and Rvk) in order to determine
the relationship between the grains size reduction and the
surface texture. As all mechanical machining processes with
undefined tool geometry (e.g. grinding, polishing,
lapping,...etc.), experimental results obtained during
measurements suggest a clear relationship between the reduction
in abrasive grains size and the surface texture. The minimum
quantity lubrication (MQL) also decreases the surface roughness;
the lubrication addition helps to achieve better surface quality
than the dry belt grinding.
Keywords: Abrasive grains,
Belt grinding, Superfinishing, Surface texture;
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The Analysis of Particle Size
Effect on Performance of WC/Cu P/M Compact Sintered Electrode in
EDM Process
R.V.S.Subrahmanyam, Koona Ramji, Pujari Srinivasa Rao,
ChundruVenkata Rao |
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Abstract: The main aim of this study is to evaluate the
influence of particle size variations on electric discharge
machining (EDM) electrodes made with a combination of Tungsten
carbide (WC) and Copper (Cu) powders using the powder metallurgy
(P/M) method. The electrodes are in cylindrical shape of 15 mm
diameter and are made with following sizes i.e., Nano Particles
(NP), a mix of Nano and Micron Particles (NMP) and Micron
Particles (MP). Electrodes, thus made in combinations were used
to study the performance during surface modification of Inconel
718 alloy using EDM. The electrodes were made with wt% 40, 50&
60 of WC and the rest is Cu, whereas the compaction ranges
200-400Mpa. Among the unconventional machining processes, EDM is
the most preferred surface modification process to machine very
hard materials like Inconel 718 alloy. Machining was conducted
by varying parameters viz., pulse on time, polarity, peak
current, %WC in tool composition, Particle size, and compaction
pressure. The performance indicators in the present
investigation are material removal rate (MRR) and tool wear rate
(TWR). The results were analyzed using MINITAB 14 software, and
it was noted that the improvement in MRR was due to the
influence of particle size and peak current. A highest MRR of
9.90 mg/min was attained with NP electrode and a peak current of
13A. The highest TWR of 20.70 mg/min was also observed at the
machining condition where highest MRR was observed. The results
of the MRR and TWR values show the significant influence of all
the six process variables on EDM process.
Keywords: EDM, WC- Cu, P/M
compact sintered electrode, MRR, TWR, Inconel 718;
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On the Use of
Rigid-Body-Translations for Determining Surface Tilt Angles in
Two-dimensional Digital Image Correlation Experiments: A
Generalized Approach
Ala Hijazi |
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Abstract: The two-dimensional digital image correlation
(2D-DIC) technique is used for making full-field in-plane
deformation/strain measurements on planar surfaces. One of the
basic requirements for making measurements using 2D-DIC is to
observe the target surface perpendicularly by the camera.
Ensuring camera perpendicularity before starting to make
measurements using 2D-DIC is important because errors will be
induced in the measured displacements/strains if the camera is
not oriented properly. During the initial setting of an
experimental setup, small camera misalignment angles of one or
two degrees can easily go undetected. This paper reports a
simple and reliable approach for verifying the camera
perpendicularity in 2D-DIC experiments, and for measuring the
tilt angle(s) if the camera is not perpendicular to the surface.
The approach uses in-plane rigid-body-translation where the
strain error(s) obtained from DIC measurements are used to
calculate the tilt angle(s). The translation can be either
parallel to the target plane (done by moving the target) or
parallel to the camera plane (done by moving the camera) where a
different set of equations is used for calculating the tilt
angles in each scenario. A translation of a known magnitude in
any in-plane direction (parallel to the x or y axes of the
image, or at any angle in between) is all what is required to
calculate the tilt angle(s). The approach is also capable to
determine the tilt angles if the target is tilted about any of
the two in-plane axes (x or y) or about the two axes
simultaneously. Several rigid-body-translation experiments are
performed under different conditions to evaluate the validity
and accuracy of this approach at tilt angles between 1° and 4°.
The results show that tilt angles as small as 1° can be
calculated accurately, and that rigid-body-translation as small
as 2% of the field-of-view width can be used for making
measurements with good accurac.
Keywords: Digital image
correlation; 2D-DIC; normal strain error; shear strain error;
strain bias; camera non-perpendicularity; camera misalignment;
tilt angle; rigid-body-translation;
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A Machine Learning Approach
for Fire-Fighting Detection in the Power Industry
Firas Basim Ismail, Ammar Al-Bazi, Rami Hikmat Al-Hadeethi,
Mathew Victor |
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Abstract: Coal kept in the coal storage yard
spontaneously catches on fire, which results in wastage and can
even cause a massive fire to break out. This phenomenon is known
as the spontaneous combustion of coal. It is a complex process
that has non-linear relationships between its causing variables.
Preventive measures to prevent the fire from spreading to other
coal piles in the vicinity have already been implemented.
However, the predictive aspect before the fire occurs is of
great necessity for the power generation sector. This research
investigates various prediction models for spontaneous coal
combustion, explicitly selecting input and output parameters to
identify a proper clinker formation prediction model.
Feed-Forward Neural Network (FFNN) is proposed as a proper
prediction model. Two Hidden Layers (2HL) network is found to be
the best with 5 minutes prediction capability. A sensitivity
analysis study is also conducted to determine the influence of
random input variables on their respective response variables.
Keywords: Spontaneous combustion of coal, Artificial
Neural Network, Clinker Formation Prediction Models, Coal-fired
power plant; |
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Characterization of Al-SiCP
Functionally Graded Metal Matrix Composites Developed through
Centrifuge Casting Technique
Kiran Aithal S, Ramesh Babu N, Manjunath HN, Chethan KS |
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Abstract: Centrifuge casting is a new technique wherein a
mold assembly is made to rotate at a certain speed that will
induce higher 'G' force to the molten metal.The existing higher
rotational force creates a compositional gradient that segregate
phases with different densities. In this work, an attempt has
been made to develop Al alloy/ SiCP FGMs. It has been observed
that due to the higher density of SiC compared to Aluminum, the
bottom part of the casting is rich in SiC particles with good
resistance to wear, and the top of the casting results in high
toughness as it is more of Al alloy. In the present work FG
Composites are produced using hypereutectic (17%Si) Al-Si alloy
using centrifuge casting technique with SiC particulate(SiCP) as
reinforcement using stir casting followed by centrifuge casting.
The samples were characterized for microstructure, hardness, and
wear. It was found that there is a gradation in the sample for
all the above said properties from top to bottom of the sample.
It was found that Al-17wt% Si matrix alloy reinforced with 2%
SiCP yielded a maximum hardness of about 66BHN at 400rpm while
for 4% and 6% the hardness was found to be 82 and 94BHN.The
results revealed that the wear resistance was high at both the
ends of the specimen due to segregation of Si at one end and
SiCp at the other end.
Keywords: FG composite,
Centrifuge casting, Microstructure, Hardness, Wear; |
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