bluuebunny/crossref_metadata_2025 huggingface dataset:
The Impact of the Bologna Agreement on Electric Power Engineering Education in Latvia
Authors: Sauhatas A. , Gerhards J. , Chuvychin V.
Published: February 2013

The fast transmission to a market form of economics in Latvia caused many complex problems, not least for electric power engineering education. As a result, there was a perceived need for reorganisation of the structure of the educational process, forms of teaching and the contents of courses. This reorganisation, and the transformation of courses and degree programmes, was applied across all educational levels to avoid too narrow a specialisation. The task was carried out with the active participation of some universities from within the European Community and with the participation of electric utilities in financing practically oriented projects. An especially successful aspect of this cooperation was participation in local research activity, which led to the development of new devices for monitoring and control of processes in electric power systems, as well as participation in a large European research project.
Bologna: Engineering the Right Outcomes
Authors: Shearman Richard
Published: February 2013

The 1999 Bologna Declaration and consequent changes in educational policy reflect a desire first to promote mobility and secondly to promote Europe as a world force in higher education in the face of challenges from elsewhere in the world. Innovative approaches to the Bologna reforms, such as outcomes-based accreditation, show great potential for realising these goals; however, they will only succeed if different national contexts are carefully considered.
SPICE BSIM3 Model Parameter Extraction and Optimisation: Practical Considerations
Authors: Abebe H. , Tyree V. , Morris H. , Vernier P. T.
Published: February 2013

This tutorial paper discusses the SPICE BSIM3v3.1 model parameter extraction and optimisation strategies that show consistency and very good accuracy in circuit simulation, less than 10% error, for practical IC design application in deep submicron processes. This paper describes an approach to BSIM3v3.1 model parameter extraction that mitigates or eliminates many of the unstable circuit behaviours observed during SPICE simulations with BSIM3v3. We present here a strategy applicable to 0.18 micron CMOS technology, in which the accuracy of the final extracted model parameters is evaluated by comparing simulations of inverter gain and a 31-stage ring oscillator with measured data.
Damping of Power Swings Using a FACTS Device of the TCPS Type: Modelling and Laboratory Experiments
Authors: Robak S. , Rasolomampionona D. D. , Januszewski M.
Published: February 2013

Considerations concerning the damping of power swings using a FACTS device like TCPS are presented in this paper. The case of a generator-infinite bus test system is taken into consideration. Phenomena have been analysed both by performing computer simulations of the mathematical model and experimental analysis in laboratory conditions. A short description is given of the laboratory set up equipped with a TCPS device used for the experimental analysis.
Introducing the Analysis of Bifurcation in Dynamical Systems by Symbolic Computation
Authors: Moreno Ubirajara F. , Peres Pedro L. D. , Bonatti Ivanil S.
Published: February 2013

The aim of this paper is to introduce a few topics about nonlinear systems that are usual in electrical engineering but are frequently disregarded in undergraduate courses. More precisely, the main subject of this paper is to present the analysis of bifurcations in dynamical systems through the use of symbolic computation. The necessary conditions for the occurrence of Hopf, saddle-node, transcritical or pitchfork bifurcations in first order state space nonlinear equations depending upon a vector of parameters are expressed in terms of symbolic computation. With symbolic computation, the relationship between the state variables and the parameters that play a crucial role in the occurrence of such phenomena can be established. Firstly, the symbolic computation is applied to a third order dynamic Lorenz system in order to familiarise the students with the technique. Then, the symbolic routines are used in the analysis of the simplified model of a power system, bringing new insights and a deeper understanding about the occurrence of these phenomena in physical systems.
A Laboratory Exercise for Impulse Voltage Testing of Power Transformers
Authors: Indulkar C. S. , Ramalingam K.
Published: February 2013

This paper describes a simple laboratory experiment related to impulse voltage testing of transformers. Students study the effects of the front and the tail resistors of the impulse generator, and the load capacitance of the transformer under test on the wave shapes in a laboratory using the available apparatus.
A Method to Derive Mutual Inductance Properties Using Electric Circuit Analysis Tools
Authors: Abatti Paulo José , Pichorim Sérgio Francisco , Schneider Bertoldo
Published: February 2013

A method to derive mutual inductance properties, using electric circuit analysis tools, is presented. This procedure may be useful in introductory circuit analysis courses, since it allows us to introduce or review, depending on students' background in electromagnetic theory, mutual inductance properties, while circuit analysis tools are being taught.
Case Study of the Introduction of Problem-Based Learning in Electronic Engineering
Authors: Mitchell John E. , Smith Jan
Published: February 2013

This paper reports on the implementation of problem-based learning (PBL) in an undergraduate electronic engineering degree programme. Initially, there is a review of literature to explore the claims made about the benefits of PBL and how these informed the development of our PBL course. This is followed by a description of the course and an explanation of our case study approach. We detail and discuss our findings in relation to theory and the development process, and conclude that from our experience PBL performs well as an adjunct to traditional teaching when considered in the context of the teaching of electronic engineering.
Electrical Engineering Students Evaluate Problem-Based Learning (PBL)
Authors: de Camargo Ribeiro Luis Roberto
Published: February 2013

This paper analyses and discusses a partial implementation of problem-based learning (PBL) from the student standpoint. PBL is an instructional approach that uses problems to initiate, focus and motivate students' acquisition of specific knowledge and development of professional skills and attitudes. In this study PBL was implemented in an administration theory module of an electrical engineering programme at a public university in Brazil. Data was collected through participant observation of classes and an end-of-term questionnaire and analysed qualitatively. Despite suggesting disadvantages such as increased workload and time consumption, superficial knowledge acquisition and deficient evaluation, results indicate a high level of student satisfaction as regards PBL and its capacity for promoting skills and attitudes cited by the literature.
A Modular, Open-Architecture D.C.-D.C. Power Conversion Laboratory
Authors: Barnes M. , Foster D. A. , Hutchins J. , Bailey M.
Published: February 2013

Today's graduates are expected to have a mix of skills and be competent as technology specialists and system designers. Many undergraduate courses are reflecting these requirements by introducing an element of systems design into their programmes and individual modules. This paper presents a power conversion laboratory based around a d.c.-d.c. power supply conversion unit that helps students understand both the system elements behind the unit's design, as well as the technology areas of power electronics required within the design. The laboratory is modular, allowing considerable flexibility in the type of experiment run and its main learning outcomes, for example whether the focus is on the power switches, the electronics, the magnetics or the control.
Obtaining State Equations for Planar Nondegenerate Linear Electric Circuits Using Mesh Analysis with Virtual Voltage Sources
Authors: Karamousantas Dimitrios Ch. , Chatzarakis George E. , Korres George N. , Katsikas Peter J.
Published: February 2013

This paper presents a method for obtaining the state equations for planar Nondegenerate Linear Electric Circuits (NDLEC), based on Mesh Analysis with Virtual Voltage Sources (MA-VVS). To apply this method, all circuit energy-storage elements and nonconvertible current sources are replaced by virtual sources. The work is mostly done by inspection.
Efficient Minimisation of Boolean Functions
Authors: Prasad V. C.
Published: February 2013

Quine Mc Cluskey's (QM) method is a popular method for minimisation of Boolean functions. This method is widely taught at undergraduate level. In this paper simple modifications are suggested to make it more efficient. They allow us to avoid repetitions in the QM method. Further, a minimal set of prime implicants is easily obtained.
A Distribution Automation System Simulator for Training and Research
Authors: Gupta R. P. , Srivastava S. C.
Published: February 2013

This paper presents the design and development of a scaled down physical model for power Distribution Automation (DA) system simulation. The developed DA system simulator is useful in providing hands-on experience to utility engineers/managers to familiarise themselves with the DA system and gain confidence in managing the power distribution system from the computer aided distribution control centre. The distribution automation system simulator can be effectively used to carry out further research work in this area. This also helps undergraduate and graduate students to understand power distribution automation technology in the laboratory environment.
A Zero-Cost, Real-Time, Windows Signal Laboratory
Authors: Leis John , Snook Chris
Published: February 2013

This paper introduces a Windows-based signal capture, display, and waveform synthesis package called ‘Win-eLab’. The software is able to run on a conventional desktop or laptop with no additional hardware, and can perform real-time Fourier analysis on audio-frequency signals. This paper is intended as an introduction to Win-eLab, aimed at motivating further use of it in both teaching and self-directed learning contexts. The use of the software to familiarize students with the concept of ‘laboratory’ instrumentation is discussed, as well as the usefulness of a simultaneous time-domain/frequency-domain display for understanding signals, particularly in signal processing and communications systems courses. It is anticipated that applications may extend beyond electrical and electronic engineering – for example, as an aid to understanding mechanical vibrations, acoustics, and in other discipline areas.
Feedback Control of T-S Fuzzy Systems Based on LTV System Theory
Authors: Gao Shiyu , Man Zhihong , Yu Xinghuo
Published: February 2013

Takage-Sugeno (T-S) fuzzy systems are equivalent to linear time-varying (LTV) systems; the theory of LTV systems can therefore be used to design global feedback controllers to stabilise T-S fuzzy systems. In this paper, a T-S fuzzy system is first transformed into its canonical form in terms of a Lyapunov transform. A global feedback controller can then be designed to assign all parallel D-spectrum eigenvalues (PD eigenvalues) of the closed-loop T-S fuzzy system to the desired locations with negative extended means. The advantage of the proposed scheme is that it allows us to design a single feedback controller to regulate the closed-loop T-S fuzzy system in the whole state-space, and guarantee that the closed-loop system is globally asymptotically stable. A simulation example is given in support of the proposed scheme.
Improving Understanding of Single Phase Transformer Behaviour through a Multimedia Tool
Authors: Fraile-Ardanuy J. , García-Gutiérrez P. , Pérez J. I. , Fraile-Mora J. J.
Published: February 2013

Many civil engineering students may show little motivation for a course in electrical machinery, because they consider it unexciting and of little importance to their professional practice. Therefore, the use of interactive computer graphics and animations can be a complementary tool for teaching these topics. This paper describes the use of Multimedia MATLAB Graphical User Interface (GUI) for studying the electric single phase transformer at undergraduate level. This Multimedia tool integrates: a description of its structural features; a video recorded in the laboratory showing the open circuit and short circuit tests; and a simulation module that allows us to perform these transformer tests and to analyse voltage regulation and the efficiency of the transformer. This GUI helps students not only to get a better understanding of the advantages and limitations of computer simulation, but also to get a better feel for the physical concepts they study in the lecture and laboratory parts of the course.
‘Learning by Doing’ Methodology Applied to the Practical Teaching of Electrical Machines
Authors: de la Hoz i Casas Jordi , de Blas del Hoyo Alfredo
Published: February 2013

An educational improvement and innovation project has been initiated in the Electrical Machines area of the Escola Universitària d'Enginyeria Tècnica Industrial de Barcelona (EUETIB) with the support of the Polytechnic University of Catalonia (UPC) and the assistance of its Department of Electrical Engineering. One of the main tasks performed within the project framework has been the design of a new active methodology for laboratory sessions. This methodology is an adaptation of the ‘learning by doing’ method to the singularities of practical work in electrical machines courses. The development and implementation of this active, student-centered methodology has yielded excellent results and allowed electrical machines courses to be accommodated to UPC's new educational models in the European High Education Area (EHEA) context. In this new environment, students play a more active role in the teaching and learning process.
Application of Advanced Digital Signal Processing Tools for Analysis of Voltage Events in Power Systems
Authors: Pérez Enrique , Barros Julio
Published: February 2013

This paper presents a digital signal processing laboratory developed for analysis of voltage events in power systems. The designed laboratory permits the analysis of simulated voltage events of different magnitude, duration and point-on-the-wave of beginning as well as the analysis of real voltage events from records taken by power quality monitoring equipment, using different signal processing tools such as r.m.s magnitude, Fourier analysis, Kalman filtering and wavelet analysis. This laboratory has been used as a benchmark in the development of new signal processing methods for the complete characterization of voltage events in power systems as well as a powerful teaching tool in electrical power quality courses.
Work Placement for Professional Experience in Electronics and Communications Engineering Education
Authors: Vaezi-Nejad S. M.
Published: February 2013

This paper describes the aims, health and safety issues, learning aspects and assessment of work placement for professional experience as an optional module offered to our undergraduate students. Some examples of activities carried out by students during their placement are also presented. It is argued that this module develops the capabilities and skills of our students as well as enabling them to become aware of the culture and structure of a working environment.
Networks of Capacitors in a D.C. Circuit
Authors: Labinac Velimir , Jusup Marko , Legovic Tarzan , Spiric Ljubomir
Published: February 2013

Suppose that an arbitrary electric circuit with a network of capacitors is connected to a d.c. e.m.f. device. Herein we address several related questions. What is the equivalent capacitance of the network? What is the voltage and charge on each capacitor? How long will it take to charge the network and will all capacitors be charged at the same time? Finally, the most challenging among these questions: how, in fact, are capacitors being charged? We answer these questions using theory and experiment adapted to the undergraduate level.
Educational Software for Studying a CBIR System
Authors: Aritonovic Goran , Starcevic Dusan
Published: February 2013

This paper presents software for training students in the field of computer vision and digital image processing. The procedure for realising the system for retrieval from a digital image collection based on colour and texture features is presented. This type of system realisation enables students to test the existing and new descriptors of colour and texture without any need to implement the complete system. What is proposed here is a simple and efficient way for storing and retrieving feature vectors of images from collections. The system is implemented by using a MATLAB program package and its tools for digital image processing, wavelet signal analysis and statistical data processing. In the paper are presented examples of testing standard descriptors of colour and texture and, for comparing descriptors, standard statistics metrics are used. We also show the example of realising a CBIR algorithm using our educational software.
Development of an MP3 Player Using an MP3 Hardware Decoder
Authors: Zoranović Aleksandar L. , Stojanović Goran M. , Malbaša Veljko D.
Published: February 2013

This paper presents an implementation of a digital audio player with the MP3 hardware decoder VS1033 as a result of a project-based course. The aim of this course is to motivate students to integrate knowledge from hardware and software in the field of microcomputer electronics and to apply them in order to create a functional device. This device uses a very low consumption MSP430F2417 microcontroller, which has built-in peripherals for serial communication with decoder, MMC/SDC memory card and dot matrix display with a resolution of 128 × 64 dots. It is able to play MP3, WMA and MIDI files and has voice recording capability.
A Variety of Approaches to the Provision of Mathematics Help for First-Year Engineering Undergraduates
Authors: Perkin Glynis , Bamforth Sarah
Published: February 2013

Loughborough University offers mathematical support to its students in a variety of different ways. This paper details four initiatives, implemented during the academic years from 2003/2004 to 2008/2009, which were targeted at first-year engineering students with either non-traditional mathematical backgrounds or identified as having significant gaps in their mathematical knowledge. The four initiatives are: a summer school, workshops, timetabled practice sessions and additional examination revision sessions. The benefits, difficulties and shortcomings associated with each of the four approaches are described. We also present findings from a questionnaire investigating student uptake of mathematics support and student perceptions of mathematics difficulty. Whilst successful in helping most students who engage, the paper suggests that it is often those students who are most in need of help who do not take advantage of the available support. Possible reasons why students are not accessing additional support are proposed.
The on-Line Teaching of Robot Visual Servoing
Authors: Perez-Vidal Carlos , Garcia Nicolas , Cervera Enric , Gracia Luis , Sabater Jose Maria
Published: February 2013

Visual servoing uses the visual information provided by cameras to control the movement of a robotic system. This paper presents an international on-line course aimed at BSc, MSc and PhD students in this subject. The course lasted for eight weeks, and its objective was to provide a general vision of those aspects related to the course theme including a special incentive: the professors teaching the course were the most important experts in this field at a global level, signifying that the students were able to gain access to a potentially higher quality of teaching than that available at an individual traditional university.
Smartphone Feedback: Using an iPhone to Improve the Distribution of Audio Feedback
Authors: Nortcliffe Anne , Middleton Andrew
Published: February 2013

Smartphones combine the flexibility of MP3 recorders and the connectivity of a PC in a discrete handheld device, thereby suggesting their application as a user friendly tool for giving recorded audio feedback efficiently. This paper describes a smartphone feedback methodology and presents findings from research on its use with 130 Level 5 (2nd year of degree study) Engineering and Computing students. The study found that the smartphone was more suitable than other technologies to the various demands of feedback production and distribution, and that this helped the tutor to manage the exceptionally stressful time associated with marking and giving feedback on top of an ongoing teaching load. Its pedagogic integration also resulted in a good dialogical experience as evidenced through student testimony.
Magnetic Balance for Teaching Metrology Concepts in Electrical Engineering
Authors: Geršak Gregor , Tacar Drago
Published: February 2013

In this paper a successful and inexpensive laboratory exercise is presented for explaining basic metrology concepts (reference value, standard, measuring error, traceability of measurement, measuring uncertainty) to undergraduate students of electrical engineering. For a better understanding, a common mass measurement was used. Mass of weights was measured by using a modified audio speaker as a weight balance, working on the principle of electromagnetic levitation. Speaker-balance measuring range was 10 g to 1000 g, with relative uncertainty of 3%. Students could learn about problems of the definition of the kilogram, about mass measurements and balances, repeatability of measurements, uncertainty budget calculations, and common measuring uncertainty contributions.
Outcomes-Based Assessment in Instrumentation and Measurement
Authors: Grodzicki G. P. , Madigan P. Q.
Published: February 2013

The Instrumentation and Measurement course unit at the University of Western Sydney is taken by third year engineering students. The unit integrates knowledge gained to date with an emphasis on practical completions. While delivery is via combined lecture/tutorials and practicals, it is in the practicals that a difference is found. Students are required to sequentially complete set practical tasks over 13 teaching weeks to the point of demonstrating correct operation to the lab supervisor. Students generally work individually, with each lab session having one or two supervisors. The tasks are completed sequentially; what is not completed one week is continued in the following week. Students work at their own pace and those with superior practical skills are not held back but may surge ahead towards the early completion of tasks. The students' enthusiasm is reflected in the exceptionally good attendance at the practical sessions.
Implementation of Industrial Automation Laboratories for E-learning
Authors: Gardel Alfredo , Bravo Ignacio , Revenga Pedro A. , Lázaro José L. , García Jorge
Published: February 2013

This paper presents an approach to teaching based on an industrial automation laboratory using e-learning. The approach is suitable for both in-class and remote access. It is based on providing remote access to laboratory facilities dedicated to industrial automation. A teaching platform is integrated into Moodle, an open-source e-learning system. Remote desktop programs were developed to allow students to access a remote PC and control the automation equipment. An IP camera is used to verify the operation. Each time a course is completed, or after any other activity in which the remote laboratory is used, a survey is made to assess the student's level of satisfaction and perceived degree of difficulty of the coursework. The results of the surveys from 25 graduate students per year are presented and discussed.
Influence of Self-Induced Vibrations on Geared Systems with Clearances
Authors: Michalopoulos D.
Published: February 2013

The behaviour of multishaft machinery involving gears with clearances and operating on sliding bearings was investigated experimentally and analytically. The model used represents the gear tooth pair and constitutes the basis for the determination of the response of such mechanical systems. In many applications including turbomachinery, machine tools and diesel engines non-linearities are present due to gear backlash, tooth stiffness and impact damping and they are susceptible to micro-vibrations. The bearing coefficient of friction versus speed and lubricant viscosity was determined experimentally and used in the analysis. A design methodology is presented that can be used to predict the dynamic behaviour of mechanical systems and can be extended to other types of multi-degree of freedom systems with clearances.
Product Case Studies for Polymer Composite Sandwich Beam Construction
Authors: Mines R. A. W.
Published: February 2013

A previous paper [1] has discussed some simplified models that describe the impact behaviour of polymer composite sandwich beams. The models were used as part of a final-year undergraduate course in impact engineering at the University of Liverpool. This paper relates these beam models to five composite constructions, namely, a surfboard, a dinghy, a solar car, a train and a helicopter. The aim of the paper is to integrate issues concerning composite materials, manufacture and structural design. The beam models are used to critique the selected product designs and to identify the effects of improvements to material properties with a view to improving beam, and hence, product performance.
Discrepancies between Theory and Experiment for a Laboratory Surge Tank Rig
Authors: Watson R.
Published: February 2013

This paper deals with the discrepancies between experimental results and the simple theory usually used for an undergraduate laboratory surge tank rig. It has been found that most are due to the ‘annular effect’ which occurs in unsteady laminar pipe flow. The results will also be of interest when interpreting physical model tests of full size surge tank systems.
A Multimedia Guide to Protective Product Packaging
Authors: Lye S. W. , Lee S. G. , Chew B. H.
Published: February 2013

A multimedia courseware on protective product packaging has been developed using a commercial authoring tool, IconAuthor™. The courseware contains general information on packaging and packaging materials, the design of expandable polystyrene foam protective packaging buffers and the moulding process. The courseware, designed with the novice designer in mind, is characterized by easy navigation, and contains self-assessment quizzes at the end of each module that is a judicious mix of questions that test both recall as well as comprehension. The choice of authoring tool is also discussed. Interactive multimedia was chosen as the medium of delivery as it has many advantages such as the inclusion of video, sound, animation, which are not found in conventional instructional media.
Algebraic Evaluation of Temperatures and Heat Transfer Rates in Simple Bodies with a 1-D Composite Lumped Model. Its Connection to the Heisler/Gröber Charts
Authors: Campo Antonio
Published: February 2013

Calculations of temperature histories and heat transfer rates in simple bodies (infinite plate, infinite cylinder and sphere) have been traditionally explained in courses on heat transfer by way of the popular Heisler/Gröber charts, which are applicable to dimensionless times, τ, greater than 0.2. This imposing restriction comes from the ‘one-term series solutions' used in their construction. The central goal of this educational paper is to predict mean, surface and centre temperatures, as well as heat transfer rates of simple bodies, by implementing a 1-D composite lumped analysis. This effortless analysis brings about a handful of algebraic equations that can be easily evaluated with a pocket-size calculator. Even more important, the same algebraic equations can be extended into the sensible subregions described by dimensionless times less than 0.2; these subregions are ignored by the Heisler/Gröber charts.
Some Observations on Carnot Cycle as the Genesis of the Heat Pipe and Thermosyphon
Authors: Cheng K. C.
Published: February 2013

The purpose of this article is to show that the limiting case of the Carnot vapor cycle with a temperature difference of only a few degrees between hot and cold reservoirs, can be interpreted as the idealized heat pipe (Carnot heat pipe) for transporting heat, utilizing the boiling condensation processes. The observation of the basic relationship (definition of absolute temperature) Q1/ Q2 = T1/ T2 for Carnot cycle reveals that the Carnot heat engine becomes a heat transfer device when the temperature difference is very small. The Clapeyron—Clausius equation for the infinitesimal (differential) Carnot vapour cycle becomes the genesis for the operating principle of the heat pipe and two-phase thermosyphon. The Carnot heat pipe is independent of the system and working fluid. Within the context of the idealized Carnot heat pipe, it is shown that thermodynamics, fluid mechanics and heat transfer (thermal sciences) are closely coupled in heat pipe operation. The present observation is based on various expositions of classical thermodynamics available in the historical literature. It is of interest to note that the Carnot vapor cycle provides the basic principle for heat pipe and two-phase thermosyphon in addition to the classical cases of heat engine, refrigeration machine and heat pump.
Applications of the Bienamé and Tchebycheff Inequalities for the ‘Structural Reliability’ and ‘Engineering Planning and Design’ Courses
Authors: Elishakoff Isaac
Published: February 2013

Some examples are given to elucidate an application of the Bienamé and Tchebycheff inequalities in the probabilistic strength of materials. These inequalities are discussed in the elective undergraduate or first-year graduate courses ‘structural reliability’ or ‘engineering planning and design’. These examples, hopefully, will be beneficial to students, in that they illustrate how simple calculations can be performed to derive estimates of structural reliability with limited information. The material discussed in this paper can be covered in a single, standard fifty-minute lecture.
A Simplified Numerical Solution of Unsteady Heat Conduction Problems with an Application to a Short Cylinder
Authors: Antar Mohamed A.
Published: February 2013

A simple numerical approach is introduced, for solving transient one-dimensional heat conduction problems, in both a plate and a long cylinder with or without internal heat generation, using spreadsheets. Details of developing the nodal equations and writing them in spreadsheet format are presented. Then, the formulated problems are used to solve transient multi-dimensional heat conduction in a short cylinder applying the principle of the separation of variables. This reduces the two-dimensional nature of the problem into a couple of one-dimensional problems that are easily solved using spreadsheets. Temperature at any location and time is obtained by combining both solutions. The method allows the easy change in time increment and Biot number in a way that make it general for solving transient heat conduction in a short cylinder. It is believed that this method is appropriate for teaching transient conduction numerically to undergraduate heat transfer students.
Maximum Specific Work for Power Optimized Endoreversible Gas Turbine Cycles
Authors: Blank David A. , Bhattacharyya Souvik
Published: February 2013

As a Carnot-like cycle the continuous Ericsson cycle represents the upper efficiency limit of multistage gas turbine operations using intercooling, reheating and regeneration. When considering linear external heat transfer modes, the theory of irreversible thermodynamics for continuous endoreversible Carnot-like cycles gives rise to an optimum efficiency at maximum power output of β= 1 — ( T L/ T H)0.5 in contrast to the upper limit of β = 1 — ( T L/ T H) obtained from classical thermodynamics for ideal Carnot-like cycles. It is shown here that, additionally, for continuous (gas turbine) endoreversible cycles like Carnot and Ericsson, the optimum specific work output at maximum power ( wopt), is exactly half of that obtained for externally reversible cycles (Carnot work, wrev ) operating between the same temperature limits (i.e. wopt = 1/2 wrev). Moreover, this optimum specific work output is the same expression for these and a family of other continuous cycles. The formulation used in the analysis makes use of the ideal gas model with constant specific heats, though the results are shown to be universal for cycles using linear heat transfer laws and using vapours and real gases having specific heats that vary only as a function of temperature. Also given for the first time for this general family of cycles are expressions for power optimized mass flow rates and the cycle operating temperatures which yield optimum power. These results quantify the absolute upper power limit for power optimized gas turbine operations where the external heat transfer is by linear modes.
Mechanical Analogs in Control Education
Authors: Hizal N. Aydin
Published: February 2013

In teaching relatively abstract concepts, it is well known that analogical phenomena in more familiar domains are quite helpful in illustrating these concepts to make them more easily understandable. In this paper, the use of mechanical analogs of some fundamental phenomena in automatic control systems which we have found helpful in teaching automatic control to mechanical engineering students is described.
Using the Ideal Gas Law and Heat Release Models to Demonstrate Timing in Spark and Compression Ignition Engines
Authors: Huffman G. David
Published: February 2013

Analysis techniques of internal combustion engines range from thermodynamic methods to complex engine design programs. Thermodynamic analyses preclude engine timing while the details of engine design programs are beyond the level of undergraduate courses. This article combines the ideal gas law with heat release models and an engineering equation solver to demonstrate timing in spark and compression ignition internal combustion engines in a manner that can be used in undergraduate courses.
A Unified Approach to the Analysis of Unidirectional and Bi-Directional Parallel Flow Heat Exchangers
Authors: Sekulić D. P.
Published: February 2013

Virtually all sources devoted to heat exchanger theory, (in particular the heat transfer textbooks), start the analyses of the main thermal features of various heat exchangers by emphasizing the differences between the two basic flow arrangements: (i) the unidirectional parallel flow (in the literature often called parallel flow or co-current flow), and (ii) bidirectional flow (in the literature often called counterflow or counter-current flow). This is justified by a convincing argument that the two arrangements correspond to the two theoretical limits of performance. Namely, among all possible flow arrangements, the unidirectional flow is characterized with the smallest and the bi-directional with the largest effectiveness. Modeling of the two arrangements is, as a rule, performed simultaneously but separately. More importantly, the concept of heat exchanger effectiveness is usually introduced as the ratio of the heat transfer rate, exchanged in a given heat exchanger, and the maximum possible heat transfer rate that could be exchanged in a hypothetical bidirectional flow (counterflow) heat exchanger of an infinitely large thermal (and physical!) size.

In contrast, this paper promotes a unified approach to both flow arrangements and advocates the use of the effectiveness definition based on a notion of the dimensionless outlet temperature of fluid stream. It is argued that this approach evades pedagogical drawbacks of formal integration of two mathematical models and, more importantly, eliminates the need for an introduction of a vague concept of ‘infinitely large counter-current heat exchanger’. Instead, a unified analysis of a single model should be performed and the effectiveness should be introduced as a figure of merit that takes into account performance only of the actual heat exchanger. This approach leads to the same final results as the conventional one, but it follows methodologically a simpler path, without a need for an early introduction of vague (although plausible) thermodynamic concepts.
Ghanaian Women and the Engineering Profession
Authors: Baryeh E. A. , Obu R. Y. , Lamptey D. L. , Baryeh N. Y.
Published: February 2013

The number of Ghanaian women in the engineering profession is very low compared to that of men, although current government policies on education promote equal educational opportunities for both sexes. A study has been conducted on some Ghanaian women engineers and women engineering students, with some input from some male engineering student counterparts, and male and female engineering lecturers.

It was found, amongst other reasons, that the absence of counselling in secondary schools, difficulties in understanding mathematical concepts, criticism and discouragement from people and the low number of female lecturers are some of the causes of low female participation in engineering. Cultural and social stereotyping of male and female roles in jobs did not worry the female engineers and engineering students. The major motivating factors were natural curiosity, mathematics and science ability, and influence from family and non-family members. They had high career aspirations of rising to management, executive positions and setting up engineering firms. The engineering lecturers and male engineering students were all in favour of increasing the participation of females in engineering. Some suggestions have been made on what to do to increase female participation in engineering.
A Note on Energy Dissipation
Authors: Bessaih N. , Sharp J. J.
Published: February 2013

The dissipation of energy in a stilling basin is often increased by the use of blocks and baffles which create additional eddies and turbulence in the flow. These are beneficial in decreasing the specific energy of the flow and in lowering depths downstream of the hydraulic jump. However it must be appreciated, by students and teachers alike, that dissipation of additional energy will increase downstream velocities. Although this should be obvious from a specific energy diagram the effects may easily be overlooked. This brief paper helps to clarify the extent of the velocity increase and provides quantitative data showing the relationship between velocity increase and specific energy decrease.
A Tool for Learning Mohr's Circle
Authors: Moller James , Mokaddem Amer
Published: February 2013

Mastery of the relations among loads on an elastic object and the corresponding stress state as well as the transformed and principal stresses at a point inside the object frequently presents a significant hurdle to Mechanics of Materials students. Mohr's circle is commonly introduced as a tool ostensibly to make transformation and principal information easier to understand and apply. Yet learning Mohr's circle construction and interpretation frequently introduces an additional challenge. A learning tool in the form of a system that gives realtime display of the stress state and its corresponding Mohr's circle at a point in a structure that the student manually loads is introduced. Rather than being a virtual learning environment, a unique synergism among a computer and a physically tangible object is reported. Visual, tactile, and muscular feedback to the learner's attempts to load and deform the object are provided. The results of learning experiments are reported. When the computer program portion of the tool is used alone, it is most effective at improving students' ability to anticipate the way in which stress magnitude varies with transformation angle and for identifying principal stresses on the circle. When the complete tool is used, learners can handle and load the structure and become distinctly more confident of their understanding of Mohr's circle than those who had not. Students who used the complete tool after working related homework problems were more satisfied with the tool man than those who did the opposite. Students who used the complete tool before working homework problems demonstrated a stronger ability to correctly locate Mohr's circle as well as to calculate maximum shear stress.
A Complete Kinematic Analogy
Authors: Rico-Martinez J. M. , Gallardo-Alvarado J.
Published: February 2013

A decade ago Roth [1] presented a kinematic analogy between angular and linear kinematic quantities which is of ‘general application’ in the sense that the analogy does not require a ‘special’ type of angular motion. Unfortunately, the analogy seemed to hold only at the velocity analysis. More precisely, when the equations for the acceleration analysis are presented, the analogy breaks down. Since that paper was presented, newer results in kinematics allow us to show that, redefining a few terms, the analogy can be extended to higher order analyses. Furthermore, it is shown that the analogy is at the heart of the theory of screws proposed by Ball one hundred years ago.
Spreadsheet Modelling of Transient Three Dimensional Heat Conduction with Various Standard Boundary Conditions
Authors: Antar Mohamed A. , Mokheimer Esmail M.
Published: February 2013

A method of analysing transient three-dimensional heat conduction problems using spreadsheets is described. An implicit numerical scheme is used and user-defined macros are designed and executed in a single-layer sheet. The method allows the use of all standard boundary conditions such as constant surface temperature, specified heat flux, thermal insulation, convection and/or thermal radiation. This method seems to be convenient for both practising engineers as well as undergraduate students since it enables them to solve engineering problems numerically without complicated programming. The method also allows the user to incorporate nonlinear boundary conditions such as thermal radiation with no further simplification which otherwise would require further effort to model. The method was received by engineering students and hence was useful as an educational aid that can be applied in other fields of engineering applications.
On the Dynamics of Variable Mass Systems
Authors: Eke F. O. , Mao T. C.
Published: February 2013

This paper accomplishes two things. It presents a derivation of the equations of motion of variable mass systems. The method presented here is based on Kane's formalism, and is complete, efficient, and mathematically rigorous—avoiding heuristics and many other pitfalls of previous attempts at such derivation. The paper also presents a detailed discussion of the meaning and importance of the various terms of the equations of motion, and the circumstances under which each term can be neglected. It is found that certain judiciously simplified versions of the equations of motion are adequate for most studies. The most important forces contributed by mass variability appear to be the thrust vector and the Coriolis force. The jet damping moment and the moment due to inertia variation are the dominant moments due to mass variability. The study ends with specific equations that are recommended for use in the study of the dynamics of variable mass systems. These equations capture all the important features of the motion of variable mass systems, while remaining simple enough to permit tractable analyses of the behaviour of such systems.
Didactic Software for the Design of Rotative Shafts
Authors: Cavalca Katia Lucchesi , Jacon Fabio Tadeu Peggau
Published: February 2013

The present work proposes the development of a program in Visual Basic to the didactics improvement in teaching machine components design, focusing the calculation procedures adopted in the design of rotative shafts, considering its dynamic behaviour as the fundamental influence in the vibrational response of a rotative machine. The design and diameters evaluation of the component, previous to its integration as a part of the rotative machine group, is done in a software developed in Visual Basic, with an interactive interface with the user, that models a presented shaft with loads, geometry and bearing position through singularity functions. This model, when analysing either the static or the dynamic condition, supplies answers to the user with respect to the shaft deflections, supports reactions, stress state and the final geometry. Viewing that the objective of that software is being used in disciplines of Mechanical Design, the same not only should be capable of calculating the shaft dimensions, obeying fatigue failure approaches and for multiaxial stress state, but also to present a didactic and simplified interface to the user.
A Membrane Stress Experiment Using Drinking Cans
Authors: Ng T. W.
Published: February 2013

A simple experiment to demonstrate membrane stresses acting in cylindrical pressure vessels is described in this work. This was accomplished by attaching strain gauges to a drinking can that was, in turn, pressurized using a bicycle pump. Despite the items used being inexpensive and commonly available, the experiment was nonetheless able to produce measurements that were close to that predicted by membrane stress theory. More importantly, it was highly successful in helping students grasp the fundamental concepts of membrane stresses in an experiential manner.
A Project-Based Approach to Teaching Numerical Methods
Authors: Musto Joseph C.
Published: February 2013

This paper describes a numerical methods course that introduces and reinforces mathematical concepts by relating them to a term-long design project. The project, involving the design of a robotic workcell, allows the students to develop and apply techniques for root finding, curve fitting, numerical differentiation, numerical integration, and optimization within the context of a team design effort. Weekly assignments require the student design team to build computational submodules to analyse pieces of the robotic system; these submodules are integrated into a large complex simulation module, which is used for design optimization. Student design teams report their design methodology and results through formal design reports and design presentations. Student feedback indicates that the teaching of numerical methods against the backdrop of a tangible design problem allows for enhanced understanding and enthusiasm for the course material.
An Interactive Knowledge-Based Multimedia Intelligent Tutoring System for Apprenticeship Training in the Precision Engineering Industry: Implementation of IPD_ITS
Authors: Cheok B. T. , Lim K. B. , Nee A. Y. C.
Published: February 2013

We discuss the cognitive aspects of skills training in progressive die design, and the ways to incorporate them into the ITS. We also give an overview of the IPD progressive die design system and explain how the design knowledge base can be exploited for development into an ITS. In this paper, we describe IPD_ITS, the tutoring module of IPD and explain its implementation for burring.
An Appraisal of A-Level and University Examination Results for Engineering Undergraduates
Authors: Adamson J. , Clifford H.
Published: February 2013

The examination performance of Mechanical Engineering undergraduate students from two comparable UK universities over a three-year study period is analysed. For each student group the examination results from each year of study are compared with each other, with the third-year project mark, with A-level results and with the results of a prior knowledge assessment test using a ranking correlation technique. The significance of the derived correlation coefficients is assessed and discussed. Subsequently, third-year marks are further appraised in relation to the combined A-level ‘score’ and A-level Mathematics ‘grade’, and the distribution of the differences between third- and first-year marks is examined.