Abstract: Tungsten Inert Gas (TIG) welding is a high quality welding process used to weld the thin metals and their alloy. 5083 Aluminium alloys play an important role in engineering and metallurgy field because of excellent corrosion properties, ease of fabrication and high specific strength coupled with best combination of toughness and formability.
TIG welding technique is one of the precise and fastest processes used in aerospace, ship and marine industries. TIG welding process is used to analyze the data and evaluate the influence of input parameters on tensile strength of 5083 Al-alloy specimens with dimensions of 100mm long x 15mm wide x 5mm thick. Welding current (I), gas flow rate (G) and welding speed (S) are the input parameters which effect tensile strength of 5083 Al-alloy welded joints. As welding speed increased, tensile strength increases first till optimum value and after that both decreases by increasing welding speed further. Results of the study show that maximum tensile strength of 129 MPa of weld joint are obtained at welding current of 240 Amps, gas flow rate of 7 Lt/min and welding speed of 98 mm/min. These values are the optimum values of input parameters which help to produce efficient weld joint that have good mechanical properties as a tensile strength.
Abstract: Simple design of a rotary valve system is capable of controlling intake and exhaust gases, which will eliminate the need of known complex mechanisms. The cost of material and production, maintenance, and noise level of the system can be further reduced. The new mechanism enables the elimination of the overlapping of valves work that reduces gas leakage. This paper examines theoretically the gas flow through the holes of a rotary valve design in a small engine. Preliminary results show that the new gas flow has many positive differences than a conventional poppet-valve system. New dependencies on the gas speed enable the finding of better solutions for the geometry of a rotary valve system that will result in a higher efficiency of an internal-combustion engine of the automotive industry.
Abstract: In the present study, two TRIP-assisted steels were designated as A (having no Cr and Cu content) and B (having higher Ni, Cr and Cu content) heat treated under different conditions, and the correlation between its heat treatment, microstructure and properties were investigated. Micro structural examination was carried out by optical microscope and scanning electron microscope after electrolytic etching. Non-destructive electrochemical and ultrasonic testing on two TRIP-assisted steels was used to find out corrosion and mechanical properties of different alter microstructure phase’s steels. Furthermore, micro structural studies accompanied by the evaluation of mechanical properties revealed that steels having martensite phases with higher corrosive and hardness value were less sound velocity and also steel’s microstructure having finer grains that was more grain boundary was less corrosion resistance. Steel containing more Cu, Ni and Cr was less corrosive compared to other steels having same processing or microstructure.
Abstract: Nanotechnology has multiple and enormous advantages for all application. Therefore, this research is carried out to synthesize and characterize bimetallic iron with copper nanoparticles. After synthesizing nano zero valent iron by reduction of ferric chloride by sodium borohydride under nitrogen purging environment, bimetallic iron with copper nanoparticles are synthesized by varying different loads of copper chloride. Due to different standard potential (E0) values of copper and iron, copper is coupled with iron at (Cu to Fe ratio of 1:5, 1:6.7, 1:10, 1:20). It is found that the resulted bimetallic Fe/Cu nanoparticles are composing phases of iron and copper. According to the diffraction patterns indicating the state of chemical combination of the bimetallic nanoparticles, the particles are well-combined and crystalline sizes are less than 1000Ao (or 100nm). Specifically, particle sizes of synthesized bimetallic Fe/Cu nanoparticles are ranging from 44.583 nm to 85.149 nm.
Abstract: This paper presents congestion management in deregulated power systems. In a deregulated environment, every buyer wants to buy power from the cheapest generator available, irrespective of relative geographical location of buyer and seller. As a consequence of this, the transmission corridors evacuating the power of cheaper generators would get overloaded if all such transactions are approved. Congestion management is a mechanism to prioritize the transactions and commit to such a schedule which would not overload the network. The congestions in the transmission lines are determined by Optimal Power Flow (OPF) solution, which is carried by primal liner programming method. Congestion in the transmission lines are alleviated by connected Distributed Generation (DG) of micro grid at load bus. A method to determine the optimal location of DG unit has been suggested based on transmission line relief sensitivity based approach. The effectiveness of proposed method has been demonstrated on modified IEEE-14 and 30 bus test systems.
Abstract: The part of “future direction” in the findings of meta-analysis could provide the great direction to conduct the future studies. This study, “The Documentary Analysis of Meta-Analysis Research in Violence of Media” would conclude “future directions” out of 10 meta-analysis papers. The purposes of this research are to find an appropriate research design or an appropriate methodology for the future research related to the topic, “violence of media”. Further research needs to explore by longitudinal and experimental design, and also needs to have a careful consideration about age effects, time spent effects, enjoyment effects and ordinary lifestyle of each media consumer.
Abstract: The newest semiconductor devices on the market are MOSFET transistors based on the silicon carbide – SiC. This material has exclusive features thanks to which it becomes a better switch than Si – silicon semiconductor switch. There are some special features that need to be understood to enable the device’s use to its full potential. The advantages and differences of SiC MOSFETs in comparison with Si IGBT transistors have been described in first part of this article. Second part describes driver for SiC MOSFET transistor and last part of article represents SiC MOSFET in the application of buck converter (step-down) and design of simple RC snubber.
Abstract: The controller is used to improve the dynamic performance of DC-DC converter by achieving a robust output voltage against load disturbances. This paper presents the performance of PI and Fuzzy controller for a phase- shifted zero-voltage switched full-bridge PWM (ZVS FB- PWM) converters with a closed loop control. The proposed converter is regulated with minimum overshoot and good stability. In this paper phase-shift control method is used as an effective tool to reduce switching losses and duty cycle losses. A 1kW/100KHz dc/dc converter is simulated and analyzed using MATLAB. The circuit is simulated for static and dynamic load (DC motor). It has been observed that performance of converter with fuzzy controller is better than that of PI controller. An efficiency comparison of the converter with a reported topology has also been carried out.
Abstract: Microarrays are made it possible to simultaneously monitor the expression profiles of thousands of genes under various experimental conditions. It is used to identify the co-expressed genes in specific cells or tissues that are actively used to make proteins. This method is used to analysis the gene expression, an important task in bioinformatics research. Cluster analysis of gene expression data has proved to be a useful tool for identifying co-expressed genes, biologically relevant groupings of genes and samples. In this work K-Means algorithms has been applied for clustering of Gene Expression Data. Further, rough set based Quick reduct algorithm has been applied for each cluster in order to select the most similar genes having high correlation. Then the ACV measure is used to evaluate the refined clusters and classification is used to evaluate the proposed method. They could identify compact clusters with feature selection method used to genes are selected.
Abstract: Tinnitus is commonly defined as an aberrant
perception of sound without external stimulus. It’s a chronic
condition with consequences on the QOL. The coping strategies used
were not always effective and coping was identified as a predictor of
QOL in individuals with tinnitus, which reinforces the idea that in
health the use of effective coping styles should be promoted. This
work intend to verify relations between coping strategies assessed by
BriefCope in subjects with tinnitus and variables such as gender, age
and severity of tinnitus measured by THI and the Visual Analogue
Scale and also hearing and hyperacusis. The results indicate that there
are any statistically significant relationships between the variables
assessed in relation to the results of BriefCope except in the Visual
Analogue Scale.These results, indicating no relationship between
almost all variables, reinforce the need for further study of coping
strategies use by these patients.
Abstract: Mobile application development is different from regular application development due to the hardware resource limitations existed in the mobile platforms. In the mobile environment, the application needs to be optimized by the developer to produce optimal software with least overhead. This study discussed about performance optimization techniques that are employed in general application development, and how such techniques are performing on mobile platforms through some empirical evaluations on a mobile emulator, Nokia X3-02 and Nokia C5-03devices. The scope of the work is only confined to mobile platform based on Java Mobile edition architecture. The empirical results showed that techniques such as loop unrolling, dependency chain, and linearized getter and setter performed better by a factor of 3 to 7. Whereas declaration and initialization on the same line or separate line did not improve the performance.
Abstract: Sea level rise threatens to increase the impact of future
storms and hurricanes on coastal communities. Accurate sea level
change prediction and supplement is an important task in determining
constructions and human activities in coastal and oceanic areas. In
this study, support vector machines (SVM) is proposed to predict
daily tidal levels along the Jeddah Coast, Saudi Arabia. The optimal
parameter values of kernel function are determined using a genetic
algorithm. The SVM results are compared with the field data and
with back propagation (BP). Among the models, the SVM is superior
to BPNN and has better generalization performance.
Abstract: In recent years, a reconstruction project for sewer
pipelines has been progressing in Japan with the aim of renewing old
sewer culverts. However, it is difficult to secure a sufficient base area
for shafts in an urban area because many streets are narrow with a
complex layout. As a result, construction in such urban areas is
generally very demanding.
In urban areas, there is a strong requirement for a safe, reliable and
economical construction method that does not disturb the public’s
daily life and urban activities. With this in mind, we developed a new
construction method called the “shield switching type micro-tunneling
method,” which integrates the micro-tunneling method and shield
method.
In this method, pipeline is constructed first for sections that are
gently curved or straight using the economical micro-tunneling
method, and then the method is switched to the shield method for
sections with a sharp curve or a series of curves without establishing
an intermediate shaft.
This paper provides the information, features and construction
examples of this newly developed method.
Abstract: Silica fume, also known as microsilica (MS) or
condensed silica fume is a by-product of the production of silicon
metal or ferrosilicon alloys. Silica fume is one of the most effective
pozzolanic additives which could be used for ultrahigh performance
and other types of concrete. Despite the fact, however is not entirely
clear, which amount of silica fume is most optimal for UHPC. Main
objective of this experiment was to find optimal amount of silica
fume for UHPC with and without thermal treatment, when different
amount of quartz powder is substituted by silica fume. In this work
were investigated four different composition of UHPC with different
amount of silica fume. Silica fume were added 0, 10, 15 and 20% of
cement (by weight) to UHPC mixture. Optimal amount of silica fume
was determined by slump, viscosity, qualitative and quantitative
XRD analysis and compression strength tests methods.
Abstract: The aim of this study is to analyze the migration
process of the rural population of Bangladesh. Heckman Probit model
with sample selection was applied in this paper to explore the
determinants of migration and intensity of migration at farm
household level. The farm survey was conducted in the central part of
Bangladesh on 160 farm households with migrant and on 154 farm
households without migrant including a total of 316 farm households.
The results from the applied model revealed that main determinants
of migration at farm household level are household age, economically
active males and females, number of young and old dependent
members in the household and agricultural land holding. On the other
hand the main determinants of intensity of migration are availability
of economically adult male in the household, number of young
dependents and agricultural land holding.
Abstract: A design problem of non-uniform circular antenna arrays for maximum reduction of both the side lobe level (SLL) and first null beam width (FNBW) is dealt with. This problem is modeled as a simple optimization problem. The method of Firefly algorithm (FFA) is used to determine an optimal set of current excitation weights and antenna inter-element separations that provide radiation pattern with maximum SLL reduction and much improvement on FNBW as well. Circular array antenna laid on x-y plane is assumed. FFA is applied on circular arrays of 8-, 10-, and 12- elements. Various simulation results are presented and hence performances of side lobe and FNBW are analyzed. Experimental results show considerable reductions of both the SLL and FNBW with respect to those of the uniform case and some standard algorithms GA, PSO and SA applied to the same problem.
Abstract: This paper describes optimal thinning of an Elliptical
Cylindrical Array (ECA) of uniformly excited isotropic antennas
which can generate directive beam with minimum relative Side Lobe
Level (SLL). The Particle Swarm Optimization (PSO) method, which
represents a new approach for optimization problems in
electromagnetic, is used in the optimization process. The PSO is used
to determine the optimal set of ‘ON-OFF’ elements that provides a
radiation pattern with maximum SLL reduction. Optimization is done
without prefixing the value of First Null Beam Width (FNBW). The
variation of SLL with element spacing of thinned array is also
reported. Simulation results show that the number of array elements
can be reduced by more than 50% of the total number of elements in
the array with a simultaneous reduction in SLL to less than -27dB.
Abstract: In Line start permanent magnet synchronous motor, eccentricity is a common fault that can make it necessary to remove the motor from the production line. However, because the motor may be inaccessible, diagnosing the fault is not easy. This paper presents an FEM that identifies different models, static eccentricity, dynamic eccentricity, and mixed eccentricity, at no load and full load. The method overcomes the difficulty of applying FEMs to transient behavior. It simulates motor speed, torque and flux density distribution along the air gap for SE,DE, and ME. This paper represents the various effects of different eccentricitiestypes on the transient performance.
Abstract: Recently, the interest of globalization in the field of
teacher education has increased. In the U.S., the government is trying
to enhance the quality of education through a global approach in
education. To do so, the schools in the U.S. are recruiting teachers with
global capability from countries like Korea where competent teachers
are being trained. Meanwhile, in the case of Korea, although excellent
teachers have been cultivated every year, due to a low birth rate it is
not easy to become a domestic teacher. To solve the trouble that the
two countries are facing, the study first examines the demand and
necessity of globalization in the field of teacher education between
Korea and the U.S. Second, we propose a new project, called the
‘Global Teachers University (GTU)’ program to satisfy the demands
of both countries. Finally, we provide its implications to build the
future educational cooperation for teacher training in a global context.
Abstract: In this research, copper borates are synthesized by the
reaction of copper sulfate pentahydrate (CuSO4.5H2O) and
tincalconite (Na2O4B7.10H2O). The experimental parameters are
selected as 80oC reaction temperature and 60 of reaction time. The
effect of mole ratio of CuSO4.5H2O to Na2O4B7.5H2O is studied. For
the identification analyses X-Ray Diffraction (XRD) and Fourier
Transform Infrared Spectroscopy (FT-IR) techniques are used. At the
end of the experiments, synthesized copper borate is matched with
the powder diffraction file of “00-001-0472” [Cu(BO2)2] and
characteristic vibrations between B and O atoms are seen. The proper
crystals are obtained at the mole ratio of 3:1. This study showed that
simplified synthesis process is suitable for the production of copper
borate minerals.