bluuebunny/crossref_metadata_2025 huggingface dataset:
Economic Evaluation of Pediatric Telemedicine Consultations to Rural Emergency Departments
Authors: Yang Nikki H. , Dharmar Madan , Yoo Byung-Kwang , Leigh J. Paul , Kuppermann Nathan , Romano Patrick S. , Nesbitt Thomas S. , Marcin James P.
Published: May 2015

Background. Comprehensive economic evaluations have not been conducted on telemedicine consultations to children in rural emergency departments (EDs). Objective. We conducted an economic evaluation to estimate the cost, effectiveness, and return on investment (ROI) of telemedicine consultations provided to health care providers of acutely ill and injured children in rural EDs compared with telephone consultations from a health care payer prospective. Methods. We built a decision model with parameters from primary programmatic data, national data, and the literature. We performed a base-case cost-effectiveness analysis (CEA), a probabilistic CEA with Monte Carlo simulation, and ROI estimation when CEA suggested cost-saving. The CEA was based on program effectiveness, derived from transfer decisions following telemedicine and telephone consultations. Results. The average cost for a telemedicine consultation was $3641 per child/ED/year in 2013 US dollars. Telemedicine consultations resulted in 31% fewer patient transfers compared with telephone consultations and a cost reduction of $4662 per child/ED/year. Our probabilistic CEA demonstrated telemedicine consultations were less costly than telephone consultations in 57% of simulation iterations. The ROI was calculated to be 1.28 ($4662/$3641) from the base-case analysis and estimated to be 1.96 from the probabilistic analysis, suggesting a $1.96 return for each dollar invested in telemedicine. Treating 10 acutely ill and injured children at each rural ED with telemedicine resulted in an annual cost-savings of $46,620 per ED. Limitations. Telephone and telemedicine consultations were not randomly assigned, potentially resulting in biased results. Conclusions. From a health care payer perspective, telemedicine consultations to health care providers of acutely ill and injured children presenting to rural EDs are cost-saving (base-case and more than half of Monte Carlo simulation iterations) or cost-effective compared with telephone consultations.
Presenting Numeric Information with Percentages and Descriptive Risk Labels
Authors: Sinayev Aleksandr , Peters Ellen , Tusler Martin , Fraenkel Liana
Published: May 2015

Background. Previous research demonstrated that providing (v. not providing) numeric information about the adverse effects (AEs) of medications increased comprehension and willingness to use medication but left open the question about which numeric format is best. The objective was to determine which of 4 tested formats (percentage, frequency, percentage + risk label, frequency + risk label) maximizes comprehension and willingness to use medication across age and numeracy levels. Methods. In a cross-sectional internet survey ( N = 368; American Life Panel, 15 May 2008 to 18 June 2008), respondents were presented with a hypothetical prescription medication for high cholesterol. AE likelihoods were described using 1 of 4 tested formats. Main outcome measures were risk comprehension (ability to identify AE likelihood from a table) and willingness to use the medication (7-point scale; not likely = 0, very likely = 6). Results. The percentage + risk label format resulted in the highest comprehension and willingness to use the medication compared with the other 3 formats (mean comprehension in percentage + risk label format = 95% v. mean across the other 3 formats = 81%; mean willingness = 3.3 v. 2.95, respectively). Comprehension differences between percentage and frequency formats were smaller among the less numerate. Willingness to use medication depended less on age and numeracy when labels were used. Generalizability is limited by the use of a sample that was older, more educated, and better off financially than national averages. Conclusions. Providing numeric AE-likelihood information in a percentage format with risk labels is likely to increase risk comprehension and willingness to use a medication compared with other numeric formats.
The Teaching of the Theory of Yield Surfaces for Perfectly Plastic Thin Shells
Authors: Robinson M.
Published: May 2015

A straightforward but complete derivation is given of the yield surface for a circular cylinder under axisymmetric loading. It is suggested that such a derivation is essential for the proper teaching of shell plasticity, and that to quote the results without proof leaves students with little understanding and confidence in the subject.
Clarification of the Evaluation of Friction Work Transfer in Control Volume Analyses
Authors: Barrow H. , Pope C. W.
Published: May 2015

Friction work transfer in control volume analyses has been critically examined with special reference to the case when the friction force is not uniform over the boundary of the control volume. By considering a particular application of a Couette flow between a stationary smooth surface and a moving rough surface with a positive pressure gradient, it is shown that an inconsistency may be introduced in quantifying the work transfer rate when the modelling of the flow is on a one-dimensional basis.
Links between the Factor-of-Safety and the Reliability Methods of Design
Authors: Latcha Michael A. , Der Hovanesian Joseph
Published: May 2015

Relationships are developed that bridge the gap between the deterministic, or factor-of-safety, approach to mechanical design and the more recent reliability, or stochastic, method. The resulting equations make it possible to incorporate stochastic data into determìnistic analyses, such as the finite element method. Estimates of design reliability can be calculated, based on the variation of the strength of the material and/or the stresses seen by the part while in service.
A Teaching Note on Failure Criteria and Failure Surfaces for Ductile and Brittle Materials
Authors: Schajer G. S.
Published: May 2015

This note discusses some basic concepts underlying isotropic material failure criteria under multiaxial loadings. It also describes the shapes and features of the associated failure surfaces in three-dimensional stress space. Failure criteria for ductile materials are first reviewed. They are then generalized so that they may also be applied to brittle materials. The relationships among the various failure criteria, the shapes and characteristics of the associated failure surfaces, and the special features of physically acceptable isotropic failure criteria are then considered.
Teaching Integrated CAD with Solid Modelling in Engineering Courses
Authors: Becker A. A. , Nadiri F.
Published: May 2015

A practical CAD course is presented for engineering undergraduate courses, using engineering examples to demonstrate how modern CAD packages are used. The CAD course is split into formal lectures and workshop sessions, and can be divided into three stages, the first two as part of the syllabus in the first two years of a three/four year B.Eng. course, and the final stage as an optional final-year course. The syllabus suggested is suitable for inclusion in a modular course. The CAD course covers 2D drafting, 3D solid modelling as well as finite element analysis, which are considered most relevant to mechanical engineers.
Heat Transfer as a Design-Oriented Course: Mechanical Supports as Thermal Insulators
Authors: Bejan Adrian
Published: May 2015

Four problems are used to show how the following objectives can be pursued in a heat transfer course: the introduction of design principles along with heat transfer science, the interdisciplinary character of heat transfer engineering, and the relationship between heat transfer and other engineering disciplines. The problems address the design question of how to select the shape and material of a mechanical support that must be a good thermal insulator at the same time. They show that the mechanical and thermal functions of the system compete against one another, and that it is possible to balance these competing objectives into an optimal design.
A Comparison of Expectations and Achievement in a Prior Knowledge Assessment of B. Eng. (Hons) Course Entrants
Authors: Clifford H.
Published: May 2015

The results of a ‘prior knowledge’ test taken by a group of 42 students at the beginning of a B. Eng. degree course in Mechanical Engineering at a UK university have been analysed and compared with the results expected by the 18 teaching staff in the department concerned. The comparison covers both overall performances and the responses to individual questions. The average student ‘score’ was 40.3%; the average expected ‘score’ was 80.7%.
The Use of Computer-Assisted Learning within Undergraduate Thermofluids Courses
Authors: Allwright R. D. , Tubman K. A.
Published: May 2015

This article describes the results of a 1992 survey into the use of computer-assisted teaching of undergraduate thermofluids within UK universities. The results do not include computer packages which are of a general scientific nature and used as aids to calculations. It is assumed that all universities are using these computer aids.

The analysis of 44 responses to a questionnaire sent out to 65 UK universities reveals that very few are using any thermofluids computer packages in the first and second undergraduate years, but about three-quarters are using some (typically 1, 2 or 3 packages) in the final year. About one-third of the packages are ‘home-produced’ by individual universities, tailored to their particular courses. Two-thirds are educational licensed versions of bought commercial packages. No single commercial package is in widespread use across the university sector, but six separate packages are in limited use.

The authors conclude this paper with their views on future developments.
Upheaval Buckling of a Mechanism under External Pressure and Compressive Loading
Authors: Plaut R. H. , Mróz Z.
Published: May 2015

A mechanical or structural element often buckles when it is compressed beyond a certain amount. Constraints may raise the value of the critical compressive load. In some cases a constraint may completely prevent the occurrence of buckling. This situation is demonstrated here by a simple two-bar model that rests on a rigid foundation and is subjected to pressure and compressive loading. If the system is ‘perfect’, buckling is not possible. However, if the foundation is not flat, or if the load is applied eccentrically, a sudden jump in deflection may occur as the load is increased.
An Extension of Rayleigh's Principle
Authors: Díaz-Jiménez Alfonso , Estévez-Bretón Gentil A.
Published: May 2015

Steidel's extension of Rayleigh's method for calculating the natural vibrational frequencies of mechanical systems with two degrees of freedom provides an elegant method to obtain exact results. In the present article this approach, which perhaps has not been exploited as much as it could be, is first reviewed and then several examples of the procedure are given. An extension of the method to three degrees of freedom is presented, and a natural generalization of Rayleigh's principle is suggested.
Derailment of Trains
Authors: Roorda J. , Gracie B.
Published: May 2015

A simple model of train derailments reduces a complex dynamic process to a recursive series of statics and geometry calculations accompanied by computation of energy dissipation by ground friction forces. A calibration of the model parameters ensures a good fit to reality. Some derailment characteristics can be predicted.
Cycle Optimization and Comparison of Ideal Thermal Cycles for Maximum Specific Output
Authors: Agnew B. , Anderson A. , Frost T. H.
Published: May 2015

The thermal efficiencies of several thermodynamic cycles are evaluated and compared for the condition of maximum specific net work output for a specified cycle temperature ratio. It is shown at this condition that the efficiencies of all of the cycles are very similar and that an objective selection of a cycle for a particular application cannot be made on the basis of thermal efficiency alone. The different cycles are then compared with respect to other important design parameters for the optimized condition and comments are made with regard to power generation and the associated controlling rate processes.
Computer-Aided Analysis of Centrifugal Compressors
Authors: Moukalled F. , Naim N. , Lakkis I.
Published: May 2015

This paper describes computer-aided analysis of centrifugal compressors (CAACC), a micro-computer-based, interactive, and menu-driven software package for use as an educational tool by mechanical engineering students studying radial flow compressors. CAACC is written in the Pascal computer language and runs on IBM PC, or compatible, computers. In addition to solving for any unknown variables, the graphical utilities of the package allow the user to display a diagrammatic sketch of the compressor and to draw velocity diagrams at several locations. Furthermore, the program allows the investigation and plotting of the variation of any parameter versus any other parameter. Through this option, the package guides the student in learning the basics of centrifugal compressors by the various performance studies that can be undertaken and graphically displayed. The comprehensive example presented demonstrates the capabilities of the package as a teaching tool.
The Bilinear Transform in Control System Simulation
Authors: Morgan C.
Published: May 2015

Digital computer simulation of a continuous control system furnishes the designer with a convenient means of assessing the effects of control strategies and can also provide an independent check on the transient and frequency responses obtained from a theoretical analysis. Although commercial packages are widely available, it is instructive to build an initial simulation using a discrete transfer function representation of the dynamic elements. The bilinear transform can be used to derive a suitable transfer function, with the necessary algebraic manipulations being performed by the computer. The method produces an inherently flexible simulation and is equally applicable to linear and nonlinear systems.
A Simple Approach to the Generalized Properties of Orthotropic Sheets
Authors: Amirbayat J.
Published: May 2015

The paper presents a simple method for derivation of four in-plane and out-of-plane properties of orthotropic sheets, which are a matter of interest to engineering students, along different directions as a helpful teaching tool. The prerequisite knowledge of students to follow the subject is undergraduate level of strength of materials.
A Simple Laboratory Experiment to Measure the Convective Heat Transfer Coefficient from a Heated Copper Rod in Air
Authors: Cloete F. L. D.
Published: May 2015

This paper describes a simple experimental rig which enables students to measure convective heat transfer coefficients between a heated copper rod and ambient air with reasonable accuracy and good repeatability. It is simple in design so that any workshop should be able to make up its own version at low cost. The interpretation of results is based on the well-known heat transfer analysis of a fin. The rig is versatile in that both free and forced convection conditions as well as unsteady-state behaviour can be demonstrated.
Two-Surface Approach to the Derivation of Anisotropic Shallow-Shell Theory Equations—Part 2: Arbitrary Loading
Authors: Mbakogu F. C. , Pavlovic M. N.
Published: May 2015

In this, the second of the two articles on a simplified method of teaching anisotropic shell theory, the governing equations of shallow shells—previously derived for the case of transverse loading—are now extended so as to cater for completely general loading. The whole approach becomes almost trivial once the two-surface notion (i.e. the splitting of the actual shell into two imaginary ‘stretching’ and ‘bending’ surfaces) is employed.
Solar Still Heat Transfer Simulation Model
Authors: Dobson R. T.
Published: May 2015

This article serves as a possible basis for the introductory lecture to a first course in heat transfer. By making use of a solar still as a practical example many of the important heat transfer concepts may be interestingly introduced. Conduction, convection and radiation and combinations thereof are all important in the analysis of the performance of a solar still. The conservation of energy and mass is applied to the components of the solar still treated as control volumes. The resulting system of simultaneous differential equations simulating the behaviour of the still are then solved numerically. The results thus obtained are compared to experimental observations. Fairly good agreement between the theoretical and experimental results were obtained, for instance the theoretical daily production of fresh water of 3.15 kg/m2 was 5% less than the experimentally measured value, and the maximum temperature of the water in the still was predicted at 15% more than the experimentally measured value of 62°C.
An Expression for the Strain Energy of Laminated Composite Thin Shells
Authors: Tse P. C. , Lai T. C.
Published: May 2015

An expression for the complementary strain energy of a linear elastic laminated composite thin-walled structure is presented which describes the energy in terms of midplane properties and subsequently stress and moment resultants rather than local stress and strain values. This expression is particularly useful for the analysis of statically indeterminate structures and energy storage devices such as springs.
Engineering Science-Led Computer-Aided Design: A Project-Based Approach
Authors: Dunne F. P. E. , Taylor D. A. W.
Published: May 2015

A project-based learning approach has been developed in which a commercial CAD package is employed to analyse and redesign a shaft and bearing system which is known to fail in service after short term use. The principal aim of the project is to emphasize the importance of the appraisal of design software packages. The students are required to apply their knowledge and understanding of the relevant engineering science to check and validate the results predicted by the software package. The project is therefore used to emphasize the importance of questioning the output obtained from software packages, and the need for validation. In addition, the project aims to introduce students to the power of the microcomputer in quickly carrying out the many iterative analyses that are often required at the detailed stages of design.

The importance of project-based design work in enabling the acquisition of skills, and the development of understanding of fundamental engineering concepts is discussed and an approach is proposed for enabling integration of design teaching with first- and second-year engineering science courses within an engineering degree course. The approach presented seeks to exploit student interest and enthusiasm for engineering project work in order to aid, and enhance the development of understanding for a particular domain of engineering science. The design project considers a ‘real’ design problem, and the hardware is made available to the students for viewing and handling. It is argued that reality plays an important role in maintaining student interest and commitment, which is essential for effective learning in design.

The paper gives an overview of the design project, and hence demonstrates how design teaching can provide an integrating theme within engineering science courses. The emphasis of the current approach on student-centred, active learning, rather than the traditional passive learning methods, is also discussed. Finally, an assessment is made of the project-based approach to design teaching and of its ability to develop understanding of engineering principles, to develop skills in CAD, and to maintain student enthusiasm using active learning techniques.
A Sound Derivation of the Nonlinear Differential Equations of Motion of a Travelling String
Authors: Bar-Avi Patrick , Porat Itzhak
Published: May 2015

Axially moving materials, such as high-speed magnetic tapes, belts and band saws, have been discussed since 1897. In this paper the nonlinear differential equations, which describe the string's plane motion (lateral and longitudinal), are developed by two different methods: direct method (Newton's second law) and Hamilton's principle. The control volume method is presented briefly. The equations are stated in two different coordinates systems. Comparison between the equations developed by the different methods and coordinates systems shows that they are the same. The coupling between the lateral and longitudinal vibrations is of the second order, hence linearization (to the first order) leads to uncoupled equations.
Stresses in Thick-Walled Cylinders: A Simple and Insightful Treatment
Authors: French M. J. , Widden M. B.
Published: May 2015

The paper introduces a method for finding stresses in thick-walled cylinders which is more direct than the usual technique. By reducing markedly the amount of algebra needed, the method helps students to see clearly how a thick-walled cylinder withstands internal pressure. Calculation of the interference needed in shrink-fitted cylinders, and of the residual stresses following autofrettage, are greatly simplified using the method.
Developing a Course on Advanced Industrial Sensors
Authors: Bradley C.
Published: May 2015

Increasing demands for higher production quality, improved manufacturing efficiency, and more stringent environmental standards have led to the development of new and complex types of industrial sensors. These sensor systems are finding widespread application in such diverse fields as machine tools, product inspection, and advanced composite aircraft. The sensors typically employ optical, ultrasonic, or microwave techniques to perform measuring functions. Most undergraduate mechanical engineering programmes do not fill this knowledge gap in the students' education and their exists a requirement for sensor engineering courses tailored to meet the background and needs of mechanical engineers. This paper describes the development of such a course, in particular, selecting the content, developing demonstrations, and acquiring video support material.
The Development of Combustion Laboratory Test Apparatus for Mechanical Engineers
Authors: Lee Dae-Hee , Bollinger B.
Published: May 2015

A combustion laboratory test apparatus has been developed and put to use in the mechanical engineering measurement course at the California State University, Sacramento. The objectives of this apparatus are to study the characteristics of a premixed flame for a range if air/propane mixtures (from near stoichiometric to rich to highly rich) and to examine the principles of chemical thermodynamics of combustion by comparing the calculated adiabatic flame temperature to the measured adiabatic flame temperature, and by doing an energy balance on the flame. The apparatus consists of a burner that is used to ignite a regulated air/propane mixture. A thin wire thermocouple is used to measure both the flame temperature profiles and the adiabatic flame temperatures for two different air/propane mixtures (rich and highly rich). Furthermore, a copper tank containing water is heated by a near-stoichiometric mixture flame, causing heat transfer from the flame to the water. The results show that approximately 83% of the heat released from the near stoichiometric flame is transferred to the water in the copper tank.
Heat-Transfer for Fins with Two-Port Theory
Authors: Lombard C.
Published: May 2015

Fin heat transfer is an essential part of the education of mechanical engineers. It represents the simplest application of the heat conduction equation: the one-dimensional, steady, case. The usual presentation of the subject involves solving the conduction equation for various boundary conditions. In this paper, two-port techniques are applied to fin heat transfer. This concept is more suitable for the training of engineers because it emphasizes the importance of the boundaries rather than the internal conduction. Besides this important conceptual aid, the matrix is a powerful aid in computations; making it much easier to solve arrangements with complicated geometry. In fact, the two-port representation makes it possible to use graph theory for the automatic solution of complicated heat-flow structures.
Analysis of a Pneumatic Cylinder System
Authors: Fok S. C. , Ong E. K.
Published: May 2015

Pneumatic cylinder systems have the potential to provide fast and reliable motion characteristics with large power output to weight at low cost to benefit ratios. To properly utilize pneumatic cylinder systems in industrial applications (especially in control situations), mechanical engineers must appreciate and understand the dynamic characteristics of these devices. In this paper, the linearized continuous time dynamics of a pneumatic rodless cylinder system are examined. Two transfer functions, based upon the midstroke and off-centre operation conditions respectively, are presented.
A Simple Experiment on Heat Transfer Using a Phase Change Material
Authors: Macías-Machín A. , Henríquez V. , Lozano A.
Published: May 2015

An experiment to calculate the heat transfer coefficient using a phase change material is described. The various tests use a naphthalene ball which changes from solid to gas. The technique is simple and inexpensive, and it is capable of yielding meaningful results.

It will be seen that the heat transfer rises with the temperature and air flowrate. Also, students will be encouraged to analyse their own results and to find other variations to this experiment. This will considerably enhance the students' understanding of the processes at work.
Spreadsheet Applications for Modelling and Analysis in Mechanical Engineering
Authors: Fraser C. J. , Thorpe J. R.
Published: May 2015

This paper outlines a number of different applications of spreadsheet solutions to mechanical engineering problems involving ideal fluid flow, two-dimensional heat transfer, plate bending and torsion of non-circular sections. The general utility of a spreadsheet in handling finite difference equations is further illustrated in an application to simulate the dynamic response of a DC voltage controlled servo-motor. Finally, since most spreadsheets also incorporate the common logical operators then any arbitrary Boolean function can be manipulated with any range of input logic states. Details are therefore included in the paper on the application of a spreadsheet to simulate and test the operation of a prototype digital logic circuit. The educational advantages in using a spreadsheet are highlighted in the variety of engineering problems which can be solved without having to resort to the specialist and generally more expensive finite element software packages.
Collapse of a Factory Chimney: An Example Problem for a Course in Dynamics
Authors: Pavier M. J.
Published: May 2015

This paper describes an example problem for a course in dynamics based on the collapse of a factory chimney. The motion of the chimney is analysed and the point during collapse when the chimney breaks into two parts is predicted. The subsequent motion is calculated allowing the eventual position of bricks originally at the top of the chimney to be estimated.
An Aircraft Longitudinal Static Stability and Control Experiment
Authors: Bloy A. W.
Published: May 2015

An experiment on aircraft longitudinal static stability and control, which is relatively easy to perform, requires minimal equipment and provides sufficiently accurate results, is described. Typical results are given for a Harrier aircraft model.
Thermal Engineering Design Project: Heat Transfer from a Cylinder in Crossflow
Authors: Mullisen R. S.
Published: May 2015

A novel thermal engineering design project involving heat transfer from a cylinder in crossflow is described. The class assignment required design of equipment, trial-and-error experimentation, data collection, and data reduction to obtain a heat transfer correlation without the use of a wind or water tunnel. The student designs involved the use of moving cars, flowing creeks, and spinning wheels as the means of obtaining the free-stream velocity; the author used a pedalled bicycle. Data reduction accounted for radiation and employed the lumped heat capacity method. The 18 student groups plus the author produced 132 data points which were collectively plotted on a modified Nusselt number versus Reynolds number plane. All of these data produced a correlation which deviated form a published empirical correlation by about 12%.
Lateral Mixing of Continuous Line Source: An Introduction to Turbulent Diffusion
Authors: Lee Joseph H. W. , Chu Paul C. K. , Yau Tony W. C.
Published: May 2015

The lateral turbulent mixing of a continuous line source of neutral tracer or contaminant in steady uniform open channel flow illustrates several useful concepts of advective diffusion. Flow visualization of the slender plume downstream of the source in a laboratory flume is presented. The self-similar tracer concentration field is obtained by both conductivity measurements and laser-induced fluorescence (L1F) techniques. The dimensionless turbulent diffusivity is determined, and the pedagogical features of the experiment are discussed.
Teaching Power Cycles by Comparative First- and Second-Law Analysis of Their Evolution
Authors: Dunbar William R. , Lior Noam
Published: May 2015

The teaching of power cycles in courses of thermodynamics or thermal engineering was traditionally based on first-law analysis. Second-law analysis was typically taught later, and not integrated with it. This approach leaves the student ignorant of the effect of operating parameters and cycle modifications on the accompanying exergy (availability) magnitudes and component irreversibilities, which are necessary for evaluating the potential for further system improvements. It also leaves many of the students with an ambiguous understanding of the exergy concept and its use. Consonant with the gradual changes in this educational approach, which increasingly attempt to integrate first- and second-law analysis, this paper recommends a strategy which integrates exergy analysis into the introduction and teaching of energy systems, demonstrated and made didactically appealing by an examination of the historical evolution of power plants, emphasizing the objectives for improvements, accomplishments, constraints, and consequently the remaining opportunities. Important conclusions from exergy analysis, not obtainable from the conventional energy analysis, were emphasized. It was found that this approach evoked the intellectual curiosity of students and increased their interest in the course.
Fundamental Optima in Thermal Science
Authors: Bejan Adrian
Published: May 2015

This paper addresses a modern trend in heat transfer education, namely, the increasingly important roles played by ‘purpose’ and thermodynamic principles in problem formulation. The answers to such basic questions represent an emerging class of fundamental optima (extrema) that are redefining thermal science. The combined heat transfer and thermodynamics models and analyses are extremely simple and brief. The method is illustrated by means of six examples: maximum rate of ice production, optimal on & off operation of defrosting refrigerators and power plants with heat exchangers that experience fouling, optimal allocation of heat exchanger equipment in power plants and refrigeration plants, and optimal spacing between elements in a fixed volume with natural or forced convection.
Two Strain Plasticity Experiments Yielding Joule's Constant
Authors: Mullisen R. S.
Published: May 2015

Two, simple, strain plasticity experiments that yield Joule's constant (J = 778 (ft lbf)/Btu) are described in this paper. One experiment uses lead-smashing and the other copper cold-working. In both experiments the lead or copper specimens have an attached thermocouple and perform as calorimeters. The equipment is easily constructed at minimal expense and may be used as laboratory experiments. The experimental results gave an average, absolute deviation from Joule's constant of 4.2% for the lead-smashing experiment and 11.8% for the copper cold-working experiment.
Computer-Aided Analysis of Hydraulic Reaction Turbines
Authors: Moukalled F. , Honein A.
Published: May 2015

A microcomputer-based educational software package designed to help mechanical engineering students to understand hydraulic reaction turbines is described. The software is interactive, menu-driven, and easy-to-use, is written in the Pascal computer language, and runs on IBM PC, or compatible, computers. The program can handle radial, mixed, or axial flow turbine problems by solving for unknown variables through a complete set of equations covering the turbine installation. Using similarity laws, model-prototype problems or operation under different conditions can also be tackled. Furthermore, the program is equipped with graphical utilities that include many diagrammatic sketches of reaction turbines, some recommended charts, and the possibility of drawing velocity triangles when corresponding variables are available. The most important feature of the package is an option that allows one to plot the variation of any parameter versus any other one. Through this option, the student can easily understand and discuss the effects of varying design parameters on the overall performance of the machine. Finally, some special features that are important in making the package user-friendly and encouraging-to-use are also available, and the comprehensive example problem provided demonstrates the capabilities of the package as an instructional tool.
A Transient Buoyancy-Driven Convection Experiment for Surfaces in Air
Authors: Mullisen R. S.
Published: May 2015

A novel, transient experiment for buoyancy-driven convection from surfaces in air is described in this paper. The experiment is applied to a heated, vertical (37 mm high), copper plate which is allowed to cool in still air and in a partial vacuum. The recorded temperature histories are reduced using numerical methods. The result is an average emissivity of 0.42 and a heat transfer correlation of NuH = 1.59 RaH0.175 in the Rayleigh number range 31 300 to 242 500. A scale analysis shows that the transient heat transfer result may be compared with a steady-state correlation.
Teaching Robotics with Projects
Authors: Gürocak Hakan B.
Published: May 2015

An overview of the organization of an elective robotics course in mechanical engineering is presented. The course consists of two main sections: (1) theoretical aspects of robotics, and (2) student projects. The student teams work on projects starting from design and ending with construction, testing and demonstration. All the projects involve software development on a personal computer for robot programming and motion sequence control. In addition, some of the projects require construction of mechanical devices, sensors, power electronics and computer interface circuits.
A Contribution to New Theorems for Moment of Inertia
Authors: Ntoko Nzumbe-Mesape
Published: May 2015

The oblique axis theorem is derived using a rotation of axis. A generalization of the approach then ables the moment of inertia of any object to be calculated about any arbitrary axis in space.
Teaching Heat Transfer Using Automotive-Related Case Studies with a Spreadsheet Analysis Package
Authors: Schumack Mark R.
Published: May 2015

Five automotive-related projects used to teach the principles of heat transfer are presented. The projects were completed by students from Ford Motor Company in the Bachelor of Mechanical Engineering programme offered by the University of Detroit Mercy. Students were required to perform their engineering calculations with the spreadsheet package Microsoft Excel™. The objectives for the use of these projects in the heat transfer course were to increase student understanding of and interest in heat transfer principles by presenting problems in a familiar context, to improve the students' ability to use spreadsheets as an engineering analysis tool, and to provide experience in dealing with the open-endedness of real engineering problems. The problem statements and solutions are described, and student performance and reaction are discussed. The projects may serve as useful course material for other instructors of heat transfer, even for students outside the automotive industry.
Thermodynamic Analysis of Waste-Heat Thermoelectric Generators
Authors: el Haj Assad Mamdouh
Published: May 2015

A thermodynamic analysis of a real waste-heat thermoelectric generator is investigated. The thermoelectric generator is considered as a heat engine cycle process with internal irreversibilities. The efficiency of the thermoelectric generator is expressed in terms of two non-dimensional parameters which are to be optimized. A finite-time thermodynamic analysis is used to optimize the temperatures of the hot and cold junctions of the real thermoelectric generator. A comparison between ideal and real waste-heat thermoelectric generators is demonstrated.
General Solutions Using the Castigliano Theorem
Authors: Ward J. P.
Published: May 2015

The Castigliano theorem of solid mechanics is normally used to obtain displacements at specific points on the surface of an elastic body. In this work it will be shown that by using fictitious forces placed in general positions the general solution for the displacement may be found without the need to solve a differential equation. The work also uses the technique to obtain an unusual derivation of the Euler-Bernoulli equation.
Solving Mechanics Problems with Physical Understanding
Authors: Zhang L. C.
Published: May 2015

This paper introduces a simple method for solving solid mechanics problems. Based on a physical consideration, the equilibrium equations of a mechanics system were transferred to corresponding dynamic ones. The static solution was then obtained as a result of damped oscillation. The bending of a simply supported elastic beam was used to demonstrate the feasibility and efficiency of the method. The paper emphasizes that solid mechanics problems can be solved effectively with a sound physical understanding.
An Interactive Multimedia Computer Program on Aircraft Stability and Control
Authors: Bloy A. W. , Turner J. T. , Rizzi A.
Published: May 2015

A pilot interactive multimedia computer program on aircraft longitudinal static stability and trim is described. The module simulates typical features of an undergraduate course and has been evaluated by third-year undergraduate students familiar with the topic. In general, favourable comments have been made, particularly concerning the ease of use, overall presentation, level of interactivity and the simulation of a wind-tunnel experiment. Applications of the program are suggested.
One-Dimensional Composite Micromechanics
Authors: Dunn Martin L.
Published: May 2015

We present an easily understood, one-dimensional development of composite micromechanics that bridges the gap between the state of the art in composites research and composites education. By developing the general framework in a one-dimensional setting, a clear exposition of the basic ideas evolves. Exact analysis is carried out as far as possible, until one arrives at a natural point where assumptions must be introduced. The nature of the necessary assumptions is then clear and they have a simple physical interpretation. The connection between the framework presented here and traditional mechanics of materials analyses is discussed at length, as is a method by which the approach can be used in conjunction with an experimental programme to assess the validity of various assumptions. The general approach in one dimension leads naturally to the extension to two and three dimensions, along with the extension to analogous physical and thermomechanical properties.
An Introduction to the Impact Behaviour of Polymer Composites Using Simplified Beam Models
Authors: Mines R. A. W.
Published: May 2015

The paper describes a final-year undergraduate course that has been taught at the University of Liverpool for the past three years. The main aims of the course are to introduce the student to the design of structures using multi-component (composite) materials and to the performance of such structures under impact loading. Given the complexity of generalized composite behaviour and of structural crashworthiness, a simple structural case is considered, namely, a beam subject to three-point bending. A feature of the course is that not only is linear structural response considered but also non-linear (progressive) structural collapse is covered. The course is split into four parts, namely: (i) analysis of composite laminae, (ii) analysis of laminated beams, (iii) local and global effects in sandwich beams, and (iv) post-failure and progressive collapse of sandwich beams. Static and impact loadings are considered. Comments are made on how the theories are simplified and communicated to the undergraduate students.
Introducing CFD to Undergraduate Chemical Engineers
Authors: Wilkinson Derek
Published: May 2015

CFD (computational fluid dynamics) has become readily accessible and is widely applied in many aspects of the processing industries. A short introduction to CFD has been included in undergraduate Chemical Engineering courses with the aim of giving students an appreciation of its principal features. This comprised three lectures followed by practical experience of commercial CFD software applied to four simple fluid flow problems. A leading aim of the course has been to encourage a sceptical approach to initial results and to indicate methods by which their validity should be established.
Integrated Data Acquisition and Control System of an Engine Testbed
Authors: Guadalupe Julio Barros , Sáiz Victor M. Moreno , Romero José Isla
Published: May 2015

This paper presents the structure and operation of an integrated data acquisition and control system for analysis of the performance characteristics of an internal combustion engine in a testbed. The system allows on-line monitoring of different engine parameters and also enables us to obtain automatically the operating curves of the engine and to compare them with those provided by the manufacturer in order to assess the condition of the engine. With this system, engineering and graduate students are able to monitor the engine continuously and to check the effect of different working conditions on its performance.
Low Cost Sun-Tracking Photovoltaic Panel
Authors: Chiang Luciano E. , Jacob Jorge E.
Published: May 2015

A photovoltaic panel (PVP) incorporating a sun-tracking system was designed, built and tested. The performance improvement obtained due to the two-axis tracking system justifies the additional cost, which is minimized by using off-the-shelf components in a compact and reliable configuration. The PVP charges two 6-V batteries which in turn are used to feed the control system using only a small proportion of the converted solar energy. Thus the entire system works autonomously and independent of geographic location. Its convenience is therefore suggested for isolated and remote low-power applications. In particular it is intended for use in desertic locations in northern Chile and, by extension, in geographically similar locations in other developing countries.
Coping with Curvilinear Coordinates
Authors: Paavola J. , Salonen E.-M.
Published: May 2015

A systematic method to generate expressions appearing in physics and engineering and valid in curvilinear orthogonal coordinates is presented. The method, which is called ‘the method of local cartesian coordinates’ achieves the same as ‘the method of moving axes’ presented in Love [1] but with a smaller effort and with more familiar mathematical tools. The main idea is: if we have an expression valid in rectangular cartesian coordinates, a corresponding expression for curvilinear orthogonal coordinates can be formed with simple steps. Some general expressions are generated, but the method can be used equally well to produce the desired formulas directly in specific cases. For this purpose, polar coordinates are employed extensively as a demonstration example.
Implementation of a Digital Controller Based on a Reduced Order Observer for an Inherently Unstable Multivariable System
Authors: Roddis R. , Wardman D.
Published: May 2015

This paper describes the design methodology of a reduced order observer and digital controller for a multivariable inherently unstable electro-hydraulic system. The paper describes the experimental techniques used to identify the parameters of the system using the Signal Processing Toolbox within Matlab, and shows the use of Matlab's Control System Toolbox to design the observer and the feedback gains. The significance of signal saturation is illustrated and the means to avoid such problems in the controller are explained.
A micromechanical debonding analysis of fiber-reinforced composites due to curing residual stress
Authors: Li Jun , Liu XiaoYu , Yao XueFeng , Yuan YaNan
Published: May 2015

The representative volume element method is used to investigate the interface debonding of fiber-reinforced composites due to curing residual stress. First, the interface debonding behavior is characterized by means of the cohesive zone model, and the effects of curing residual stresses on the fiber/resin interface debonding are also studied using the cure hardening instantaneously linear elastic model. Second, debonding envelops of the representative volume element are obtained for tension loading, shear loading and mixed loading, respectively, which indicate that the curing residual stresses will have an important influence on the maximum principal stress and have no effects on the debonding initiation location and the propagating path. Finally, the relationships between the fiber versus resin aspect ratio γ and the maximum principal stress at the fiber/resin interface of the representative volume element in fiber-reinforced composites are investigated as well.
Bucklings interactions in columns made by built-up thin, open, pultruded FRP shapes
Authors: Russo Salvatore
Published: May 2015

This research evaluates the presence of buckling modes in built-up columns made from pultruded fiber reinforced polymer (FRP) profiles when flexural instability is coupled with torsional instability. This phenomenon is already well known in the field of steel construction and is tested and emphasized with the use of thin walled open cross sections of pultruded FRP materials in testing to analyze the effects of local buckling due to FRP’s orthotropy and high deformability. Also through previous tests on columns made by singular “C” shapes that create the built-up columns tested, the study presents the confidence between experimental results for the pultruded FRP built-up columns and the available formulas for calculating the expected buckling interactions. The investigation shows that torsional-flexural buckling is confirmed but is also combined with a local buckling that first influences the buckling interactions. From a practical application point of view, the study examines a comparison between experimental and formulation characterization of buckling analysis with open cross sections assumed as equivalent to the built-up cross sections. The ratio between the different critical loads and their chronology to collapse is described.