Abstract: Laser Metal Deposition (LMD) is an additive manufacturing process with capabilities that include: producing new
part directly from 3 Dimensional Computer Aided Design (3D CAD)
model, building new part on the existing old component and repairing an existing high valued component parts that would have
been discarded in the past. With all these capabilities and its advantages over other additive manufacturing techniques, the
underlying physics of the LMD process is yet to be fully understood probably because of high interaction between the processing
parameters and studying many parameters at the same time makes it
further complex to understand. In this study, the effect of laser power
and powder flow rate on physical properties (deposition height and
deposition width), metallurgical property (microstructure) and
mechanical (microhardness) properties on laser deposited most
widely used aerospace alloy are studied. Also, because the Ti6Al4V
is very expensive, and LMD is capable of reducing buy-to-fly ratio
of aerospace parts, the material utilization efficiency is also studied.
Four sets of experiments were performed and repeated to establish repeatability using laser power of 1.8 kW and 3.0 kW, powder flow
rate of 2.88 g/min and 5.67 g/min, and keeping the gas flow rate and
scanning speed constant at 2 l/min and 0.005 m/s respectively. The
deposition height / width are found to increase with increase in laser
power and increase in powder flow rate. The material utilization is favoured by higher power while higher powder flow rate reduces
material utilization. The results are presented and fully discussed.
Abstract: Computers are increasingly being used as educational
tools in elementary/primary schools worldwide. A specific
application of such computer use, is that of multimedia games, where
the aim is to combine pedagogy and entertainment. This study
reports on a case-study whereby an educational multimedia game has
been developed for use by elementary school children. The stages of
the application-s design, implementation and evaluation are
presented. Strengths of the game are identified and discussed, and its
weaknesses are identified, allowing for suggestions for future redesigns.
The results show that the use of games can engage children
in the learning process for longer periods of time with the added
benefit of the entertainment factor.
Abstract: In this paper, we first show a relationship between two
stabilizing controllers, which presents an extended feedback system
using two stabilizing controllers. Then, we apply this relationship to
the two-stage compensator design. In this paper, we consider singleinput
single-output plants. On the other hand, we do not assume the
coprime factorizability of the model. Thus, the results of this paper
are based on the factorization approach only, so that they can be
applied to numerous linear systems.
Abstract: This paper presents comparative emission study of
newly introduced gasoline/LPG bifuel automotive engine in Indian
market. Emissions were tested as per LPG-Bharat stage III driving
cycle. Emission tests were carried out for urban cycle and extra urban
cycle. Total time for urban and extra urban cycle was 1180 sec.
Engine was run in LPG mode by using conversion system. Emissions
were tested as per standard procedure and were compared. Corrected
emissions were computed by deducting ambient reading from sample
reading. Paper describes detail emission test procedure and results
obtained. CO emissions were in the range of38.9 to 111.3 ppm. HC
emissions were in the range of 18.2 to 62.6 ppm. Nox emissions were
08 to 3.9 ppm and CO2 emissions were from 6719.2 to 8051 ppm.
Paper throws light on emission results of LPG vehicles recently
introduced in Indian automobile market. Objectives of this
experimental study were to measure emissions of engines in gasoline
& LPG mode and compare them.
Abstract: The purpose of this study was primarily assessing how important economic factors namely: The Thai export price of white rice, the exchange rate, and the world rice consumption affect the overall Thai white rice export, using historical data during the period 1989-2013 from the Thai Rice Exporters Association, and Food and Agricultural Organization of the United Nations. The co-integration method, regression analysis, and error correction model were applied to investigate the econometric model. The findings indicated that in the long-run, the world rice consumption, the exchange rate, and the Thai export price of white rice were the important factors affecting the export quantity of Thai white rice respectively, as indicated by their significant coefficients. Meanwhile, the rice export price was an important factor affecting the export quantity of Thai white rice in the short-run. This information is useful in the business, export opportunities, price competitiveness, and policymaker in Thailand.
Abstract: This paper discusses a new, systematic approach to
the synthesis of a NP-hard class of non-regenerative Boolean
networks, described by FON[FOFF]={mi}[{Mi}], where for every
mj[Mj]∈{mi}[{Mi}], there exists another mk[Mk]∈{mi}[{Mi}], such
that their Hamming distance HD(mj, mk)=HD(Mj, Mk)=O(n), (where
'n' represents the number of distinct primary inputs). The method
automatically ensures exact minimization for certain important selfdual
functions with 2n-1 points in its one-set. The elements meant for
grouping are determined from a newly proposed weighted incidence
matrix. Then the binary value corresponding to the candidate pair is
correlated with the proposed binary value matrix to enable direct
synthesis. We recommend algebraic factorization operations as a post
processing step to enable reduction in literal count. The algorithm
can be implemented in any high level language and achieves best
cost optimization for the problem dealt with, irrespective of the
number of inputs. For other cases, the method is iterated to
subsequently reduce it to a problem of O(n-1), O(n-2),.... and then
solved. In addition, it leads to optimal results for problems exhibiting
higher degree of adjacency, with a different interpretation of the
heuristic, and the results are comparable with other methods.
In terms of literal cost, at the technology independent stage, the
circuits synthesized using our algorithm enabled net savings over
AOI (AND-OR-Invert) logic, AND-EXOR logic (EXOR Sum-of-
Products or ESOP forms) and AND-OR-EXOR logic by 45.57%,
41.78% and 41.78% respectively for the various problems.
Circuit level simulations were performed for a wide variety of
case studies at 3.3V and 2.5V supply to validate the performance of
the proposed method and the quality of the resulting synthesized
circuits at two different voltage corners. Power estimation was
carried out for a 0.35micron TSMC CMOS process technology. In
comparison with AOI logic, the proposed method enabled mean
savings in power by 42.46%. With respect to AND-EXOR logic, the
proposed method yielded power savings to the tune of 31.88%, while
in comparison with AND-OR-EXOR level networks; average power
savings of 33.23% was obtained.
Abstract: From past many decades human beings are suffering
from plethora of natural disasters. Occurrence of disasters is a
frequent process; it changes conceptual myths as more and more
advancement are made. Although we are living in technological era
but in developing countries like Pakistan disasters are shaped by
socially constructed roles. The need is to understand the most
vulnerable group of society i.e. females; their issues are complex in
nature because of undermined gender status in the society. There is a
need to identify maximum issues regarding females and to enhance
the achievement of millennium development goals (MDGs). Gender
issues are of great concern all around the globe including Pakistan.
Here female visibility in society is low, and also during disasters, the
failure to understand the reality that concentrates on double burden
including productive and reproductive care. Women have to
contribute a lot in society so we need to make them more disaster
resilient. For this non-structural measures like awareness, trainings
and education must be carried out. In rural and in urban settings in
any disaster like earthquake or flood, elements like gender
perspective, their age, physical health, demographic issues contribute
towards vulnerability. In Pakistan the gender issues in disasters were
of less concern before 2005 earthquake and 2010 floods. Significant
achievements are made after 2010 floods when gender and child cell
was created to provide all facilities to women and girls. The aim of
the study is to highlight all necessary facilities in a disaster to build
coping mechanism in females from basic rights till advance level
including education.
Abstract: Salinity is a measure of the amount of salts in the
water. Total Dissolved Solids (TDS) as salinity parameter are often
determined using laborious and time consuming laboratory tests, but
it may be more appropriate and economical to develop a method
which uses a more simple soil salinity index. Because dissolved ions
increase salinity as well as conductivity, the two measures are
related. The aim of this research was determine of constant
coefficients for predicting of Total Dissolved Solids (TDS) based on
Electrical Conductivity (EC) with Statistics of Correlation
coefficient, Root mean square error, Maximum error, Mean Bias
error, Mean absolute error, Relative error and Coefficient of residual
mass. For this purpose, two experimental areas (S1, S2) of Khuzestan
province-IRAN were selected and four treatments with three
replications by series of double rings were applied. The treatments
were included 25cm, 50cm, 75cm and 100cm water application. The
results showed the values 16.3 & 12.4 were the best constant
coefficients for predicting of Total Dissolved Solids (TDS) based on
EC in Pilot S1 and S2 with correlation coefficient 0.977 & 0.997 and
191.1 & 106.1 Root mean square errors (RMSE) respectively.
Abstract: We report the results of an lattice Boltzmann
simulation of magnetohydrodynamic damping of sidewall convection
in a rectangular enclosure filled with a porous medium. In particular
we investigate the suppression of convection when a steady magnetic
field is applied in the vertical direction. The left and right vertical
walls of the cavity are kept at constant but different temperatures
while both the top and bottom horizontal walls are insulated. The
effects of the controlling parameters involved in the heat transfer and
hydrodynamic characteristics are studied in detail. The heat and mass
transfer mechanisms and the flow characteristics inside the enclosure
depended strongly on the strength of the magnetic field and Darcy
number. The average Nusselt number decreases with rising values of
the Hartmann number while this increases with increasing values of
the Darcy number.
Abstract: To deal with random delays in Networked Control System (NCS), Modified Fuzzy PID Controller is introduced in this paper to implement real-time control adaptively. Via adjusting the control signal dynamically, the system performance is improved. In this paper, the design process and the ultimate simulation results are represented. Finally, examples and corresponding comparisons prove the significance of this method.
Abstract: This paper presents the outcomes of a qualitative
study which aims to investigate the pedagogical potentials of serious
games in the preparation of future teachers. The authors discuss the
existing problems and barriers associated with the organization of
teaching practices in Bulgaria as part of the pre-service teacher
training, as well as the attitudes and perceptions of the interviewed
academics, teachers and trainees concerning the integration of serious
games in the teaching practicum. The study outcomes strongly
confirm the positive attitudes of the respondents to the introduction
of virtual learning environments for the development of professional
skills of future teachers as a supplement to the traditional forms of
education. Through the inclusion of serious games it is expected to
improve the quality of practical training of pre-service teachers as
they overcome many of the problems identified in the existing
teaching practices. The outcomes of the study will inform the design
of the educational simulation software which is part of the project
SimAula Tomorrow's Teachers Training.
Abstract: Heating is inevitable in any bearing operation. This
leads to not only the thinning of the lubricant but also could lead to a
thermal deformation of the bearing. The present work is an attempt to
analyze the influence of thermal deformation on the thermohydrodynamic
lubrication of infinitely long tilted pad slider rough
bearings. As a consequence of heating the slider is deformed and is
assumed to take a parabolic shape. Also the asperities expand leading
to smaller effective film thickness. Two different types of surface
roughness are considered: longitudinal roughness and transverse
roughness. Christensen-s stochastic approach is used to derive the
Reynolds-type equations. Density and viscosity are considered to be
temperature dependent. The modified Reynolds equation, momentum
equation, continuity equation and energy equation are decoupled and
solved using finite difference method to yield various bearing
characteristics. From the numerical simulations it is observed that the
performance of the bearing is significantly affected by the thermal
distortion of the slider and asperities and even the parallel sliders
seem to carry some load.
Abstract: Isobaric vapor-liquid equilibrium measurements are
reported for binary mixture of 2-Methyltetrahydrofuran and Cumene
at 97.3 kPa. The data were obtained using a vapor recirculating type
(modified Othmer's) equilibrium still. The mixture shows slight
negative deviation from ideality. The system does not form an
azeotrope. The experimental data obtained in this study are
thermodynamically consistent according to the Herington test. The
activity coefficients have been satisfactorily correlated by means of
the Margules, and NRTL equations. Excess Gibbs free energy has
been calculated from the experimental data. The values of activity
coefficients have also been obtained by the UNIFAC group
contribution method.
Abstract: This paper presents the possibilities of using Weibull statistical distribution in modeling the distribution of defects in ERP systems. There follows a case study, which examines helpdesk records of defects that were reported as the result of one ERP subsystem upgrade. The result of the applied modeling is in modeling the reliability of the ERP system from a user perspective with estimated parameters like expected maximum number of defects in one day or predicted minimum of defects between two upgrades. Applied measurement-based analysis framework is proved to be suitable in predicting future states of the reliability of the observed ERP subsystems.
Abstract: In this paper a novel method for multiple one dimensional real valued sinusoidal signal frequency estimation in the presence of additive Gaussian noise is postulated. A computationally simple frequency estimation method with efficient statistical performance is attractive in many array signal processing applications. The prime focus of this paper is to combine the subspace-based technique and a simple peak search approach. This paper presents a variant of the Propagator Method (PM), where a collaborative approach of SUMWE and Propagator method is applied in order to estimate the multiple real valued sine wave frequencies. A new data model is proposed, which gives the dimension of the signal subspace is equal to the number of frequencies present in the observation. But, the signal subspace dimension is twice the number of frequencies in the conventional MUSIC method for estimating frequencies of real-valued sinusoidal signal. The statistical analysis of the proposed method is studied, and the explicit expression of asymptotic (large-sample) mean-squared-error (MSE) or variance of the estimation error is derived. The performance of the method is demonstrated, and the theoretical analysis is substantiated through numerical examples. The proposed method can achieve sustainable high estimation accuracy and frequency resolution at a lower SNR, which is verified by simulation by comparing with conventional MUSIC, ESPRIT and Propagator Method.
Abstract: Properties of cement pastes with fine-ground ceramics
used as an alternative binder replacing Portland cement up to 20% of
its mass are investigated. At first, the particle size distribution of
cement and fine-ground ceramics is measured using laser analyser.
Then, the material properties are studied in the early hardening
period up to 28 days. The hydration process of studied materials is
monitored by electrical conductivity measurement using TDR
sensors. The changes of materials- structures within the hardening are
observed using pore size distribution measurement. The compressive
strength measurements are done as well. Experimental results show
that the replacement of Portland cement by fine-ground ceramics in
the amount of up to 20% by mass is acceptable solution from the
mechanical point of view. One can also assume similar physical
properties of designed materials to the reference material with only
Portland cement as binder.
Abstract: Development, calibration and validation of a threedimensional
model of the Legform impactor for pedestrian crash with
bumper are presented. Lower limb injury is becoming an increasingly
important concern in vehicle safety for both occupants and
pedestrians. In order to prevent lower extremity injuries to a
pedestrian when struck by a car, it is important to elucidate the
loadings from car front structures on the lower extremities and the
injury mechanism caused by these loadings. An impact test
procedure with a legform addressing lower limb injuries in car
pedestrian accidents has been proposed by EEVC/WG17. In this
study a modified legform impactor is introduced and validated
against EEVC/WG17 criteria. The finite element model of this
legform is developed using LS-DYNA software. Total mass of
legform impactor is 13.4 kg.Technical specifications including the
mass and location of the center of gravity and moment of inertia
about a horizontal axis through the respective centre of gravity in
femur and tibia are determined. The obtained results of legform
impactor static and dynamic tests are as specified in the
EEVC/WG17.
Abstract: In the analysis of structures, the nonlinear effects due to large displacement, large rotation and materially-nonlinear are very important and must be considered for the reliable analysis. The non-linear fmite element analysis has potential as usable and reliable means for analyzing of civil structures with the availability of computer technology. In this research the large displacements and materially nonlinear behavior of shear wall is presented with developing of fmite element code using the standard Galerkin weighted residual formulation. Two-dimensional plane stress model was carried out to present the shear wall response. Total Lagangian formulation, which is computationally more effective, is used in the formulation of stiffness matrices and the Newton-Raphson method is applied for the solution of nonlinear transient equations. The details of the program formulation are highlighted and the results of the analyses are presented, along with a comparison of the response of the structure with Ansys software results. The presented model in this paper can be developed for nonlinear analysis of civil engineering structures with different material behavior and complicated geometry.
Abstract: In the paper we presented the possibility of application
collagen gels with active principle-s from marine algae extract and chlorhexidine salt in dental medicine. The hydro-alcoholic extracts
from marine algae have been used as they have been obtained. The extracts from marine algae and chlorhexidine salt (digluconate) are
incorporated in type I non-denatured fibrillar collagen matrixes. In order to obtain therapeutic effects at nanostructure level, it is important to know the rheological characteristics of the relevant mixtures of collagen gels and extracts from marine algae selected for use. In this survey we have studied mixtures made of non-denatured
fibrillar collagen hydro-gels where different concentrations of marine
algae have been incorporated. Based on the data obtained for the
shearing tensions, we have traced the rheograms – the diagrams for shearing tensions depending on the shearing speed values – from
which we have calculated the apparent viscosities as ratios between shearing tension and speed values, which have been figured in
relation to the shearing speed values, with a view to levelling
dependency.
Abstract: This work presents a new algorithm based on a combination of fuzzy (FUZ), Dynamic Programming (DP), and Genetic Algorithm (GA) approach for capacitor allocation in distribution feeders. The problem formulation considers two distinct objectives related to total cost of power loss and total cost of capacitors including the purchase and installation costs. The novel formulation is a multi-objective and non-differentiable optimization problem. The proposed method of this article uses fuzzy reasoning for sitting of capacitors in radial distribution feeders, DP for sizing and finally GA for finding the optimum shape of membership functions which are used in fuzzy reasoning stage. The proposed method has been implemented in a software package and its effectiveness has been verified through a 9-bus radial distribution feeder for the sake of conclusions supports. A comparison has been done among the proposed method of this paper and similar methods in other research works that shows the effectiveness of the proposed method of this paper for solving optimum capacitor planning problem.