Abstract: Motion response of floating structures is of great
concern in marine engineering. Nonlinearity is an inherent property
of any floating bodies subjected to irregular waves. These floating
structures are continuously subjected to environmental loadings from
wave, current, wind etc. This can result in undesirable motions of the
vessel which may challenge the operability. For a floating body to
remain in its position, it should be able to induce a restoring force
when displaced. Mooring is provided to enable this restoring force.
This paper discusses the hydrodynamic performance and motion
characteristics of an 8 point spread mooring system applied to a pipe
laying barge operating in the West African sea. The modelling of the
barge is done using a computer aided-design (CAD) software
RHINOCEROS. Irregular waves are generated using a suitable wave
spectrum. Both frequency domain and time domain analysis is done.
Numerical simulations based on potential theory are carried out to
find the responses and hydrodynamic performance of the barge in
both free floating as well as moored conditions. Initially, potential
flow frequency domain analysis is done to obtain the Response
Amplitude Operator (RAO) which gives an idea about the structural
motion in free floating state. RAOs for different wave headings are
analyzed. In the following step, a time domain analysis is carried out
to obtain the responses of the structure in the moored condition. In
this study, wave induced motions are only taken into consideration.
Wind and current loads are ruled out and shall be included in further
studies. For the current study, 2000 seconds simulation is taken. The
results represent wave induced motion responses, mooring line
tensions and identify critical mooring lines.
Abstract: Teaching of mathematics to engineering students is an
open ended problem in education. The main goal of mathematics
learning for engineering students is the ability of applying a wide
range of mathematical techniques and skills in their engineering
classes and later in their professional work. Most of the
undergraduate engineering students and faculties feels that no efforts
and attempts are made to demonstrate the applicability of various
topics of mathematics that are taught thus making mathematics
unavoidable for some engineering faculty and their students. The lack
of understanding of concepts in engineering mathematics may hinder
the understanding of other concepts or even subjects. However, for
most undergraduate engineering students, mathematics is one of the
most difficult courses in their field of study. Most of the engineering students never understood mathematics or
they never liked it because it was too abstract for them and they could
never relate to it. A right balance of application and concept based
teaching can only fulfill the objectives of teaching mathematics to
engineering students. It will surely improve and enhance their
problem solving and creative thinking skills. In this paper, some practical (informal) ways of making
mathematics-teaching application based for the engineering students
is discussed. An attempt is made to understand the present state of
teaching mathematics in engineering colleges. The weaknesses and
strengths of the current teaching approach are elaborated. Some of
the causes of unpopularity of mathematics subject are analyzed and a
few pragmatic suggestions have been made. Faculty in mathematics
courses should spend more time discussing the applications as well as
the conceptual underpinnings rather than focus solely on strategies
and techniques to solve problems. They should also introduce more
‘word’ problems as these problems are commonly encountered in
engineering courses. Overspecialization in engineering education
should not occur at the expense of (or by diluting) mathematics and
basic sciences. The role of engineering education is to provide the
fundamental (basic) knowledge and to teach the students simple
methodology of self-learning and self-development. All these issues
would be better addressed if mathematics and engineering faculty
join hands together to plan and design the learning experiences for
the students who take their classes. When faculties stop competing
against each other and start competing against the situation, they will
perform better. Without creating any administrative hassles these
suggestions can be used by any young inexperienced faculty of
mathematics to inspire engineering students to learn engineering
mathematics effectively.
Abstract: The out-of-band impedance environment is considered
to be of paramount importance in engineering the in-band impedance
environment. Presenting the frequency independent and constant outof-
band impedances across the wide modulation bandwidth is
extremely important for reliable device characterization for future
wireless systems. This paper presents an out-of-band impedance
optimization scheme based on simultaneous engineering of
significant baseband components IF1 (twice the modulation
frequency) and IF2 (four times the modulation frequency) and higher
baseband components such as IF3 (six times the modulation
frequency) and IF4 (eight times the modulation frequency) to
engineer the in-band impedance environment. The investigations
were carried out on a 10W GaN HEMT device driven to deliver a
peak envelope power of approximately 40.5dBm under modulated
excitation. The presentation of frequency independent baseband
impedances to all the significant baseband components whilst
maintaining the optimum termination for fundamental tones as well
as reactive termination for 2nd harmonic under class-J mode of
operation has outlined separate optimum impedances for best
intermodulation (IM) linearity.
Abstract: Biodiesel is widely investigated to solve the twin
problem of depletion of fossil fuel and environmental degradation.
The main objective of the present work is to compare performance,
emissions, and combustion characteristics of biodiesel derived from
cotton seed oil in a diesel engine with the baseline results of
petrodiesel fuel. Tests have been conducted on a single cylinder, four
stroke CIDI diesel engine with a speed of 1500 rpm and a fixed
compression ratio of 17.5 at different load conditions. The
performance parameters evaluated include brake thermal efficiency,
brake specific fuel consumption, brake power, indicated mean
effective pressure, mechanical efficiency, and exhaust gas
temperature. Regarding combustion study, cylinder pressure, rate of
pressure rise, net heat release rate, cumulative heat release, mean gas
temperature, mass fraction burned, and fuel line pressure were
evaluated. The emission parameters such as carbon monoxide, carbon
dioxide, un-burnt hydrocarbon, oxides of nitrogen, and smoke
opacity were also measured by a smoke meter and an exhaust gas
analyzer and compared with baseline results. The brake thermal
efficiency of cotton seed oil methyl ester (CSOME) was lower than
that of petrodiesel and brake specific fuel consumption was found to
be higher. However, biodiesel resulted in the reduction of carbon
dioxide, un-burnt hydrocarbon, and smoke opacity at the expense of
nitrogen oxides. Carbon monoxide emissions for biodiesel was higher
at maximum output power. It has been found that the combustion
characteristics of cotton seed oil methyl ester closely followed those
of standard petrodiesel. The experimental results suggested that
biodiesel derived from cotton seed oil could be used as a good
substitute to petrodiesel fuel in a conventional diesel without any
modification.
Abstract: The paper focuses on the distance laboratory
organisation for training the electrical engineering staff and students
in the fields of electrical drive and power electronics. To support
online knowledge acquisition and professional enhancement, new
challenges in remote education based on an active learning approach
with self-assessment have been emerged by the authors. Following
the literature review and explanation of the improved assessment
methodology, the concept and technological basis of the labs
arrangement are presented. To decrease the gap between the distance
study of the up-to-date equipment and other educational activities in
electrical engineering, the improvements in the following-up the
learners’ progress and feedback composition are introduced. An
authoring methodology that helps to personalise knowledge
acquisition and enlarge Web-based possibilities is described.
Educational management based on self-assessment is discussed.
Abstract: Holistic methods covering the development process as
a whole – e.g. systems engineering – have established themselves in
product design. However, technical product optimization,
representing improvements in efficiency and/or minimization of loss,
usually applies to single components of a system. A holistic approach
is being defined based on a hierarchical point of view of systems
engineering. This is subsequently presented using the example of an
electromechanical flywheel energy storage system for automotive
applications.
Abstract: Journal bearings used in IC engines are prone to premature
failures and are likely to fail earlier than the rated life due to
highly impulsive and unstable operating conditions and frequent
starts/stops. Vibration signature extraction and wear debris analysis
techniques are prevalent in industry for condition monitoring of
rotary machinery. However, both techniques involve a great deal of
technical expertise, time, and cost. Limited literature is available on
the application of these techniques for fault detection in reciprocating
machinery, due to the complex nature of impact forces that
confounds the extraction of fault signals for vibration-based analysis
and wear prediction. In present study, a simulation model was developed to investigate
the bearing wear behaviour, resulting because of different operating
conditions, to complement the vibration analysis. In current
simulation, the dynamics of the engine was established first, based on
which the hydrodynamic journal bearing forces were evaluated by
numerical solution of the Reynold’s equation. In addition, the
essential outputs of interest in this study, critical to determine wear
rates are the tangential velocity and oil film thickness between the
journals and bearing sleeve, which if not maintained appropriately,
have a detrimental effect on the bearing performance. Archard’s wear prediction model was used in the simulation to
calculate the wear rate of bearings with specific location information
as all determinative parameters were obtained with reference to crank
rotation. Oil film thickness obtained from the model was used as a
criterion to determine if the lubrication is sufficient to prevent contact
between the journal and bearing thus causing accelerated wear. A
limiting value of 1 μm was used as the minimum oil film thickness
needed to prevent contact. The increased wear rate with growing
severity of operating conditions is analogous and comparable to the
rise in amplitude of the squared envelope of the referenced vibration
signals. Thus on one hand, the developed model demonstrated its
capability to explain wear behaviour and on the other hand it also
helps to establish a co-relation between wear based and vibration
based analysis. Therefore, the model provides a cost effective and
quick approach to predict the impending wear in IC engine bearings
under various operating conditions.
Abstract: Test automation allows performing difficult and time
consuming manual software testing tasks efficiently, quickly and
repeatedly. However, development and maintenance of automated
tests is expensive, so it needs a proper prioritization what to automate
first. This paper describes a simple yet efficient approach for such
prioritization of test cases based on the effort needed for both manual
execution and software test automation. The suggested approach is
very flexible because it allows working with a variety of assessment
methods, and adding or removing new candidates at any time. The
theoretical ideas presented in this article have been successfully
applied in real world situations in several software companies by the
authors and their colleagues including testing of real estate websites,
cryptographic and authentication solutions, OSGi-based middleware
framework that has been applied in various systems for smart homes,
connected cars, production plants, sensors, home appliances, car head
units and engine control units (ECU), vending machines, medical
devices, industry equipment and other devices that either contain or
are connected to an embedded service gateway.
Abstract: Bottom ash from Municipal Solid Waste Incineration
(MSWI) can be viewed as a typical granular material because these
industrial by-products result from the incineration of various
domestic wastes. MSWI bottom ash is mainly used in road
engineering in substitution of the traditional natural aggregates. As
the characterization of their mechanical behavior is essential in order
to use them, specific studies have been led over the past few years. In
the first part of this paper, the mechanical behavior of MSWI bottom
ash is studied with triaxial tests. After, analysis of the experiment
results, the simulation of triaxial tests is carried out by using the
software package CESAR-LCPC. As the first approach in modeling
of this new class material, the Mohr-Coulomb model was chosen to
describe the evolution of material under the influence of external
mechanical actions.
Abstract: Maintenance and design engineers have great concern
for the functioning of rotating machineries due to the vibration
phenomenon. Improper functioning in rotating machinery originates
from the damage to rolling element bearings. The status of rolling
element bearings require advanced technologies to monitor their
health status efficiently and effectively. Avoiding vibration during
machine running conditions is a complicated process. Vibration
simulation should be carried out using suitable sensors/ transducers to
recognize the level of damage on bearing during machine operating
conditions. Various issues arising in rotating systems are interlinked
with bearing faults. This paper presents an approach for fault
diagnosis of bearings using neural networks and time/frequencydomain
vibration analysis.
Abstract: The statistical study has become indispensable for various fields of knowledge. Not any different, in Geotechnics the study of probabilistic and statistical methods has gained power considering its use in characterizing the uncertainties inherent in soil properties. One of the situations where engineers are constantly faced is the definition of a probability distribution that represents significantly the sampled data. To be able to discard bad distributions, goodness-of-fit tests are necessary. In this paper, three non-parametric goodness-of-fit tests are applied to a data set computationally generated to test the goodness-of-fit of them to a series of known distributions. It is shown that the use of normal distribution does not always provide satisfactory results regarding physical and behavioral representation of the modeled parameters.
Abstract: The occurrences of precipitation, also commonly
referred as rain, in the form of "convective" and "stratiform" have
been identified to exist worldwide. In this study, the radar return
echoes or known as reflectivity values acquired from radar scans
have been exploited in the process of classifying the type of rain
endured. The investigation use radar data from Malaysian
Meteorology Department (MMD). It is possible to discriminate the
types of rain experienced in tropical region by observing the vertical
characteristics of the rain structure. .Heavy rain in tropical region
profoundly affects radiowave signals, causing transmission
interference and signal fading. Required wireless system fade margin
depends on the type of rain. Information relating to the two
mentioned types of rain is critical for the system engineers and
researchers in their endeavour to improve the reliability of
communication links. This paper highlights the quantification of
percentage occurrences over one year period in 2009.
Abstract: Green and renewable energy is getting extraordinary
consideration today, because of ecological concerns made by blazing
of fossil powers. Photovoltaic and wind power generation are the
basic decisions for delivering power in this respects. Producing
power by the sun based photovoltaic systems is known to the world,
yet control makers may get confounded to pick between on-grid and
off-grid systems. In this exploration work, an endeavor is made to
compare the off-grid (stand-alone) and on-grid (grid-connected)
frameworks. The work presents relative examination, between two
distinctive PV frameworks situated at V.V.P. Engineering College,
Rajkot. The first framework is 100 kW remain solitary and the
second is 60 kW network joined. The real-time parameters compared
are; output voltage, load current, power in-flow, power output,
performance ratio, yield factor, and capacity factor. The voltage
changes and the power variances in both frameworks are given
exceptional consideration and the examination is made between the
two frameworks to judge the focal points and confinements of both
the frameworks.
Abstract: Inspired by the Formula-1 competition, IMechE
(Institute of Mechanical Engineers) and Formula SAE (Society of
Mechanical Engineers) organize annual competitions for University
and College students worldwide to compete with a single-seat racecar
they have designed and built. Design of the chassis or the frame is a
key component of the competition because the weight and stiffness
properties are directly related with the performance of the car and the
safety of the driver. In addition, a reduced weight of the chassis has
direct influence on the design of other components in the car. Among
others, it improves the power to weight ratio and the aerodynamic
performance. As the power output of the engine or the battery
installed in the car is limited to 80 kW, increasing the power to
weight ratio demands reduction of the weight of the chassis, which
represents the major part of the weight of the car. In order to reduce
the weight of the car, ION Racing team from University of
Stavanger, Norway, opted for a monocoque design. To ensure
fulfilment of the competition requirements of the chassis, the
monocoque design should provide sufficient torsional stiffness and
absorb the impact energy in case of possible collision. The study reported in this article is based on the requirements for
Formula Student competition. As part of this study, diverse
mechanical tests were conducted to determine the mechanical
properties and performances of the monocoque design. Upon a
comprehensive theoretical study of the mechanical properties of
sandwich composite materials and the requirements of monocoque
design in the competition rules, diverse tests were conducted
including 3-point bending test, perimeter shear test and test for
absorbed energy. The test panels were homemade and prepared with
equivalent size of the side impact zone of the monocoque, i.e. 275
mm x 500 mm, so that the obtained results from the tests can be
representative. Different layups of the test panels with identical core
material and the same number of layers of carbon fibre were tested
and compared. Influence of the core material thickness was also
studied. Furthermore, analytical calculations and numerical analysis
were conducted to check compliance to the stated rules for Structural
Equivalency with steel grade SAE/AISI 1010. The test results were
also compared with calculated results with respect to bending and
torsional stiffness, energy absorption, buckling, etc. The obtained results demonstrate that the material composition
and strength of the composite material selected for the monocoque
design has equivalent structural properties as a welded frame and thus
comply with the competition requirements. The developed analytical
calculation algorithms and relations will be useful for future
monocoque designs with different lay-ups and compositions.
Abstract: Microcantilevers are the basic MEMS devices, which
can be used as sensors, actuators and electronics can be easily built
into them. The detection principle of microcantilever sensors is based
on the measurement of change in cantilever deflection or change in its
resonance frequency. The objective of this work is to explore the
analogies between mechanical and electrical equivalent of
microcantilever beams. Normally scientists and engineers working in
MEMS use expensive software like CoventorWare, IntelliSuite,
ANSYS/Multiphysics etc. This paper indicates the need of developing
electrical equivalent of the MEMS structure and with that, one can
have a better insight on important parameters, and their interrelation of
the MEMS structure. In this work, considering the mechanical model
of microcantilever, equivalent electrical circuit is drawn and using
force-voltage analogy, it is analyzed with circuit simulation software.
By doing so, one can gain access to powerful set of intellectual tools
that have been developed for understanding electrical circuits Later
the analysis is performed using ANSYS/Multiphysics - software based
on finite element method (FEM). It is observed that both mechanical
and electrical domain results for a rectangular microcantlevers are in
agreement with each other.
Abstract: Common Platform for Automated Programming
(CPAP) is defined in details. Two versions of CPAP are described:
Cloud based (including set of components for classic programming,
and set of components for combined programming); and Knowledge
Based Automated Software Engineering (KBASE) based (including
set of components for automated programming, and set of
components for ontology programming). Four KBASE products
(Module for Automated Programming of Robots, Intelligent Product
Manual, Intelligent Document Display, and Intelligent Form
Generator) are analyzed and CPAP contributions to automated
programming are presented.
Abstract: In the past years electric mobility became part of a
public discussion. The trend to fully electrified vehicles instead of
vehicles fueled with fossil energy has notably gained momentum.
Today nearly every big car manufacturer produces and sells fully
electrified vehicles, but electrified vehicles are still not as competitive
as conventional powered vehicles. As the traction battery states the
largest cost driver, lowering its price is a crucial objective. In
addition to improvements in product and production processes a nonnegligible,
but widely underestimated cost driver of production can
be found in logistics, since the production technology is not
continuous yet and neither are the logistics systems. This paper presents an approach to evaluate cost factors on
different designs of load carrier systems. Due to numerous
interdependencies, the combination of costs factors for a particular
scenario is not transparent. This is effecting actions for cost reduction
negatively, but still cost reduction is one of the major goals for
simultaneous engineering processes. Therefore a concurrent and
phase appropriate cost valuation method is necessary to serve cost
transparency. In this paper the four phases of this cost valuation
method are defined and explained, which based upon a new approach
integrating the logistics development process in to the integrated
product and process development.
Abstract: Response Surface Methods (RSM) provide
statistically validated predictive models that can then be manipulated
for finding optimal process configurations. Variation transmitted to
responses from poorly controlled process factors can be accounted
for by the mathematical technique of propagation of error (POE),
which facilitates ‘finding the flats’ on the surfaces generated by
RSM. The dual response approach to RSM captures the standard
deviation of the output as well as the average. It accounts for
unknown sources of variation. Dual response plus propagation of
error (POE) provides a more useful model of overall response
variation. In our case, we implemented this technique in predicting
compressive strength of concrete of 28 days in age. Since 28 days is
quite time consuming, while it is important to ensure the quality
control process. This paper investigates the potential of using design
of experiments (DOE-RSM) to predict the compressive strength of
concrete at 28th day. Data used for this study was carried out from
experiment schemes at university of Benghazi, civil engineering
department. A total of 114 sets of data were implemented. ACI mix
design method was utilized for the mix design. No admixtures were
used, only the main concrete mix constituents such as cement, coarseaggregate,
fine aggregate and water were utilized in all mixes.
Different mix proportions of the ingredients and different water
cement ratio were used. The proposed mathematical models are
capable of predicting the required concrete compressive strength of
concrete from early ages.
Abstract: This paper introduces a signal monitoring program
developed with a view to helping electrical engineering students get
familiar with sensors with digital output. Because the output of digital
sensors cannot be simply monitored by a measuring instrument such as
an oscilloscope, students tend to have a hard time dealing with digital
sensors. The monitoring program runs on a PC and communicates with
an MCU that reads the output of digital sensors via an asynchronous
communication interface. Receiving the sensor data from the MCU,
the monitoring program shows time and/or frequency domain plots of
the data in real time. In addition, the monitoring program provides a
serial terminal that enables the user to exchange text information with
the MCU while the received data is plotted. The user can easily
observe the output of digital sensors and configure the digital sensors
in real time, which helps students who do not have enough experiences
with digital sensors. Though the monitoring program was programmed
in the Matlab programming language, it runs without the Matlab since
it was compiled as a standalone executable.
Abstract: The use of Computer Aided Design (CAD)
technologies has become pervasive in the Architecture, Engineering
and Construction (AEC) industry. This has led to its inclusion as an
important part of the training module in the curriculum for
Architecture Schools in Nigeria. This paper examines the ethical
questions that arise in the implementation of Computer Aided Design
(CAD) Content of the curriculum for Architectural education. Using
existing literature, it begins this scrutiny from the propriety of
inclusion of CAD into the education of the architect and the
obligations of the different stakeholders in the implementation
process. It also examines the questions raised by the negative use of
computing technologies as well as perceived negative influence of
the use of CAD on design creativity. Survey methodology was
employed to gather data from the Department of Architecture,
Chukwuemeka Odumegwu Ojukwu University Uli, which has been
used as a case study on how the issues raised are being addressed.
The paper draws conclusions on what will make for successful ethical
implementation.