Stroud, K A
2013-01-01
A groundbreaking and comprehensive reference that's been a bestseller since it first debuted in 1970, the new seventh edition of Engineering Mathematics has been thoroughly revised and expanded. Providing a broad mathematical survey, this innovative volume covers a full range of topics from the very basic to the advanced. Whether you're an engineer looking for a useful on-the-job reference or want to improve your mathematical skills, or you are a student who needs an in-depth self-study guide, Engineering Mathematics is sure to come in handy time and time again.
Bird, John
2014-01-01
A practical introduction to the core mathematics required for engineering study and practiceNow in its seventh edition, Engineering Mathematics is an established textbook that has helped thousands of students to succeed in their exams.John Bird's approach is based on worked examples and interactive problems. This makes it ideal for students from a wide range of academic backgrounds as the student can work through the material at their own pace. Mathematical theories are explained in a straightforward manner, being supported by practical engineering examples and applications in order to ensure
Mathematical methods in engineering
Machado, José
2014-01-01
This book presents a careful selection of the contributions presented at the Mathematical Methods in Engineering (MME10) International Symposium, held at the Polytechnic Institute of Coimbra- Engineering Institute of Coimbra (IPC/ISEC), Portugal, October 21-24, 2010. The volume discusses recent developments about theoretical and applied mathematics toward the solution of engineering problems, thus covering a wide range of topics, such as: Automatic Control, Autonomous Systems, Computer Science, Dynamical Systems and Control, Electronics, Finance and Economics, Fluid Mechanics and Heat Transfer, Fractional Mathematics, Fractional Transforms and Their Applications, Fuzzy Sets and Systems, Image and Signal Analysis, Image Processing, Mechanics, Mechatronics, Motor Control and Human Movement Analysis, Nonlinear Dynamics, Partial Differential Equations, Robotics, Acoustics, Vibration and Control, and Wavelets.
MATHEMATICS EDUCATION FOR LOGISTICS ENGINEERING
BÉLA ILLÉS; GABRIELLA BOGNÁR
2012-01-01
Mathematics is a crucial language in all engineering courses and researches where mathematical modeling, simulation and manipulation are commonly used. Engineering Mathematics courses are considered difficult courses in engineering curricula. This is reflected in engineering students’ performance at the end of each semester for these courses. Our goal is to overview a few questions on mathematics as a core subject of engineering.
Higher engineering mathematics
John Bird
2014-01-01
A practical introduction to the core mathematics principles required at higher engineering levelJohn Bird's approach to mathematics, based on numerous worked examples and interactive problems, is ideal for vocational students that require an advanced textbook.Theory is kept to a minimum, with the emphasis firmly placed on problem-solving skills, making this a thoroughly practical introduction to the advanced mathematics engineering that students need to master. The extensive and thorough topic coverage makes this an ideal text for upper level vocational courses. Now in
Advanced engineering mathematics
Jeffrey, Alan
2001-01-01
Advanced Engineering Mathematics provides comprehensive and contemporary coverage of key mathematical ideas, techniques, and their widespread applications, for students majoring in engineering, computer science, mathematics and physics. Using a wide range of examples throughout the book, Jeffrey illustrates how to construct simple mathematical models, how to apply mathematical reasoning to select a particular solution from a range of possible alternatives, and how to determine which solution has physical significance. Jeffrey includes material that is not found in works of a similar nature, such as the use of the matrix exponential when solving systems of ordinary differential equations. The text provides many detailed, worked examples following the introduction of each new idea, and large problem sets provide both routine practice, and, in many cases, greater challenge and insight for students. Most chapters end with a set of computer projects that require the use of any CAS (such as Maple or Mathematica) th...
Bird, John
2014-01-01
Introductory mathematics written specifically for students new to engineering Now in its sixth edition, Basic Engineering Mathematics is an established textbook that has helped thousands of students to succeed in their exams. John Bird's approach is based on worked examples and interactive problems. This makes it ideal for students from a wide range of academic backgrounds as the student can work through the material at their own pace. Mathematical theories are explained in a straightforward manner, being supported by practical engineering examples and applications in order to ensure that readers can relate theory to practice. The extensive and thorough topic coverage makes this an ideal text for introductory level engineering courses. This title is supported by a companion website with resources for both students and lecturers, including lists of essential formulae, multiple choice tests, full solutions for all 1,600 further questions contained within the practice exercises, and biographical information on t...
Engineering mathematics pocket book
Bird, John
2008-01-01
This compendium of essential formulae, definitions, tables and general information provides the mathematical information required by students, technicians, scientists and engineers in day-to-day engineering practice. A practical and versatile reference source, now in its fourth edition, the layout has been changed and the book has been streamlined to ensure the information is even more quickly and readily available - making it a handy companion on-site, in the office as well as for academic study. It also acts as a practical revision guide for those undertaking BTEC Nationals, Higher Nationals and NVQs, where engineering mathematics is an underpinning requirement of the course.All the essentials of engineering mathematics - from algebra, geometry and trigonometry to logic circuits, differential equations and probability - are covered, with clear and succinct explanations and illustrated with over 300 line drawings and 500 worked examples based in real-world application. The emphasis throughout the book is on ...
Bolton, W
2012-01-01
Mathematics for Engineering has been carefully designed to provide a maths course for a wide ability range, and does not go beyond the requirements of Advanced GNVQ. It is an ideal text for any pre-degree engineering course where students require revision of the basics and plenty of practice work. Bill Bolton introduces the key concepts through examples set firmly in engineering contexts, which students will find relevant and motivating. The second edition has been carefully matched to the Curriculum 2000 Advanced GNVQ units:
Engineering Mathematics in Context
DEFF Research Database (Denmark)
Ravn, Ole; Henriksen, Lars Bo
2017-01-01
A theory-based approach to scientific research has an inherent tendency to become secluded from the ongoing problems and discussions of the surrounding society. A problem-based approach to research immediately involves this context of problems and discussions from the outset. In this article, we ...... argue that education in university engineering mathematics should take its outset in contextual problems in order to provide a foundation for the skills and capabilities engineers need in their future job settings, whether it be research or development activities....
Mathematics in physics and engineering
Irving, J; Massey, H S W; Brueckner, Keith A
1959-01-01
Mathematics in Physics and Engineering describes the analytical and numerical (desk-machine) methods that arise in pure and applied science, including wave equations, Bessel and Legendre functions, and matrices. The manuscript first discusses partial differential equations, as well as the method of separation of variables, three-dimensional wave equation, diffusion or heat flow equation, and wave equation in plane and cylindrical polar coordinates. The text also ponders on Frobenius' and other methods of solution. Discussions focus on hypergeometric equation, Bessel's equation, confluent hyper
Understanding engineering mathematics
Cox, Bill
2001-01-01
* Unique interactive style enables students to diagnose their strengths and weaknesses and focus their efforts where needed* Ideal for self-study and tutorial work, building from an initially supportive approach to the development of independent learning skills * Free website includes solutions to all exercises, additional topics and applications, guide to learning mathematics, and practice materialStudents today enter engineering courses with a wide range of mathematical skills, due to the many different pre-university qualifications studied. Bill Cox''s aim is for students to gain a thorough understanding of the maths they are studying, by first strengthening their background in the essentials of each topic. His approach allows a unique self-paced study style, in which students Review their strengths and weaknesses through self-administered diagnostic tests, then focus on Revision where they need it, to finally Reinforce the skills required.The book is structured around a highly successful ''transition'' ma...
Ganesh, A
2009-01-01
About the Book: This book Engineering Mathematics-II is designed as a self-contained, comprehensive classroom text for the second semester B.E. Classes of Visveswaraiah Technological University as per the Revised new Syllabus. The topics included are Differential Calculus, Integral Calculus and Vector Integration, Differential Equations and Laplace Transforms. The book is written in a simple way and is accompanied with explanatory figures. All this make the students enjoy the subject while they learn. Inclusion of selected exercises and problems make the book educational in nature. It shou
Mathematics for Physicists and Engineers.
Organisation for Economic Cooperation and Development, Paris (France).
The text is a report of the OEEC Seminar on "The Mathematical Knowledge Required by the Physicist and Engineer" held in Paris, 1961. There are twelve major papers presented: (1) An American Parallel (describes the work of the Panel on Physical Sciences and Engineering of the Committee on the Undergraduate Program in Mathematics of the Mathematical…
Applied Mathematical Problems in Engineering
Directory of Open Access Journals (Sweden)
Carlos Llopis-Albert
2016-10-01
Full Text Available There is a close relationship between engineering and mathematics, which has led to the development of new techniques in recent years. Likewise the developments in technology and computers have led to new ways of teaching mathematics for engineering students and the use of modern techniques and methods. This research aims to provide insight on how to deal with mathematical problems for engineering students. This is performed by means of a fuzzy set/Qualitative Comparative Analysis applied to conflict resolution of Public Participation Projects in support to the EU Water Framework Directive.
Teaching Mathematics to Civil Engineers
Sharp, J. J.; Moore, E.
1977-01-01
This paper outlines a technique for teaching a rigorous course in calculus and differential equations which stresses applicability of the mathematics to problems in civil engineering. The method involves integration of subject matter and team teaching. (SD)
Mathematics in Engineering - Part I
Indian Academy of Sciences (India)
tion of mathematics to engineering problems; to provide a taste of some ... for organizations like ISRO or DRDO are called scien- tists. ... analysis and development of measurable physical data, using .... Any serious discussion of mathematics in modern engi- neering .... A simple way to solve this problem computationally is.
Power systems engineering and mathematics
Knight, U G
1972-01-01
Power Systems Engineering and Mathematics investigates the application of mathematical aids, particularly the techniques of resource planning, to some of the technical-economic problems of power systems engineering. Topics covered include the process of engineering design and the use of computers in system design and operation; power system planning and operation; time scales and computation in system operation; and load prediction and generation capacity. This volume is comprised of 13 chapters and begins by outlining the stages in the synthesis of designs (or operating states) for engineerin
Essentials engineering mathematics
Jeffrey, Alan
2004-01-01
Real numbers, inequalities and intervalsFunction, domain and rangeBasic coordinate geometryPolar coordinatesMathematical inductionBinomial theoremCombination of functionsSymmetry in functions and graphsInverse functionsComplex numbers; real and imaginary formsGeometry of complex analysisModulus-argument form of a complex numberRoots of complex numbersLimitsOne-sided limitsDerivativesLeibniz's formulaDifferentialsDifferentiation of inverse trigonometric functionsImplicit differentiationParametrically defined curves and parametric differentiationThe exponential functionThe logarithmic functionHy
Irreversible Brownian Heat Engine
Taye, Mesfin Asfaw
2017-10-01
We model a Brownian heat engine as a Brownian particle that hops in a periodic ratchet potential where the ratchet potential is coupled with a linearly decreasing background temperature. We show that the efficiency of such Brownian heat engine approaches the efficiency of endoreversible engine η =1-√{{Tc/Th}} [23]. On the other hand, the maximum power efficiency of the engine approaches η ^{MAX}=1-({Tc/Th})^{1\\over 4}. It is shown that the optimized efficiency always lies between the efficiency at quasistatic limit and the efficiency at maximum power while the efficiency at maximum power is always less than the optimized efficiency since the fast motion of the particle comes at the expense of the energy cost. If the heat exchange at the boundary of the heat baths is included, we show that such a Brownian heat engine has a higher performance when acting as a refrigerator than when operating as a device subjected to a piecewise constant temperature. The role of time on the performance of the motor is also explored via numerical simulations. Our numerical results depict that the time t and the external load dictate the direction of the particle velocity. Moreover, the performance of the heat engine improves with time. At large t (steady state), the velocity, the efficiency and the coefficient of performance of the refrigerator attain their maximum value. Furthermore, we study the effect of temperature by considering a viscous friction that decreases exponentially as the background temperature increases. Our result depicts that the Brownian particle exhibits a fast unidirectional motion when the viscous friction is temperature dependent than that of constant viscous friction. Moreover, the efficiency of this motor is considerably enhanced when the viscous friction is temperature dependent. On the hand, the motor exhibits a higher performance of the refrigerator when the viscous friction is taken to be constant.
Mathematical model of the Amazon Stirling engine
Energy Technology Data Exchange (ETDEWEB)
Vidal Medina, Juan Ricardo [Universidad Autonoma de Occidente (Colombia)], e-mail: jrvidal@uao.edu.co; Cobasa, Vladimir Melian; Silva, Electo [Universidade Federal de Itajuba, MG (Brazil)], e-mail: vlad@unifei.edu.br
2010-07-01
The Excellency Group in Thermoelectric and Distributed Generation (NEST, for its acronym in Portuguese) at the Federal University of Itajuba, has designed a Stirling engine prototype to provide electricity to isolated regions of Brazil. The engine was designed to operate with residual biomass from timber process. This paper presents mathematical models of heat exchangers (hot, cold and regenerator) integrated into second order adiabatic models. The general model takes into account the pressure drop losses, hysteresis and internal losses. The results of power output, engine efficiency, optimal velocity of the exhaust gases and the influence of dead volume in engine efficiency are presented in this paper. The objective of this modeling is to propose improvements to the manufactured engine design. (author)
Salzbrenner, R.
1984-06-01
The mechanical shape memory effect associated with a thermoelastic martensitic transformation can be used to convert heat directly into mechanical work. Laboratory simulation of two types of heat engine cycles (Stirling and Ericsson) has been performed to measure the amount of work available/cycle in a Ni-45 at. pct Ti alloy. Tensile deformations at ambient temperature induced martensite, while a subsequent increase in temperature caused a reversion to the parent phase during which a load was carried through the strain recovery (i.e., work was accomplished). The amount of heat necessary to carry the engines through a cycle was estimated from calorimeter measurements and the work performed/cycle. The measured efficiency of the system tested reached a maximum of 1.4 percent, which was well below the theoretical (Carnot) maximum efficiency of 35.6 percent.
Line integral on engineering mathematics
Wiryanto, L. H.
2018-01-01
Definite integral is a basic material in studying mathematics. At the level of calculus, calculating of definite integral is based on fundamental theorem of calculus, related to anti-derivative, as the inverse operation of derivative. At the higher level such as engineering mathematics, the definite integral is used as one of the calculating tools of line integral. the purpose of this is to identify if there is a question related to line integral, we can use definite integral as one of the calculating experience. The conclusion of this research says that the teaching experience in introducing the relation between both integrals through the engineer way of thinking can motivate and improve students in understanding the material.
Acoustical heat pumping engine
Wheatley, J.C.; Swift, G.W.; Migliori, A.
1983-08-16
The disclosure is directed to an acoustical heat pumping engine without moving seals. A tubular housing holds a compressible fluid capable of supporting an acoustical standing wave. An acoustical driver is disposed at one end of the housing and the other end is capped. A second thermodynamic medium is disposed in the housing near to but spaced from the capped end. Heat is pumped along the second thermodynamic medium toward the capped end as a consequence both of the pressure oscillation due to the driver and imperfect thermal contact between the fluid and the second thermodynamic medium. 2 figs.
Heat engine driven by purely quantum information
Park, Jung Jun; Kim, Kang-Hwan; Sagawa, Takahiro; Kim, Sang Wook
2013-01-01
The key question of this paper is whether work can be extracted from a heat engine by using purely quantum mechanical information. If the answer is yes, what is its mathematical formula? First, by using a bipartite memory we show that the work extractable from a heat engine is bounded not only by the free energy change and the sum of the entropy change of an individual memory but also by the change of quantum mutual information contained inside the memory. We then find that the engine can be ...
The mathematics of nuclear engineering
International Nuclear Information System (INIS)
Lewins, J.D.
1982-01-01
The mathematics of nuclear engineering is considered with especial reference to the problems of; the representation of the transformation of matter at the nuclear level by radioactive decay and neutron transmutation, the problem of the distribution of neutrons and other particles as a transport theory problem including some of the approximation methods used in this problem, particularly diffusion theory with particular emphasis on steady-state problems, time-dependent reactor kinetic and control, and the longer term changes involved with the nuclear fuel cycle both within and without the reactor itself. (U.K.)
Mathematical concepts for mechanical engineering design
Asli, Kaveh Hariri; Aliyev, Soltan Ali Ogli
2013-01-01
PrefaceIntroductionHeat Flow: From Theory to PracticeDispersed Fluid and Ideal Fluid MechanicsModeling for Pressure Wave into Water PipelineHeat Transfer and Vapor BubbleMathematical Concepts and Computational Approaches on Hydrodynamics InstabilityMathematical Concepts and Dynamic ModelingModeling for Predictions of Air Entrance into Water PipelineIndex
Situated Mathematics Teaching within Electrical Engineering Courses
Hennig, Markus; Mertsching, Bärbel; Hilkenmeier, Frederic
2015-01-01
The initial phase of undergraduate engineering degree programmes often comprises courses requiring mathematical expertise which in some cases clearly exceeds school mathematics, but will be imparted only later in mathematics courses. In this article, an approach addressing this challenge by way of example within a "fundamentals of electrical…
Modern mathematics for the engineer second series
1961-01-01
This volume and its predecessor were conceived to advance the level of mathematical sophistication in the engineering community. The books particularly focus on material relevant to solving the kinds of mathematical problems regularly confronted by engineers. Suitable as a text for advanced undergraduate and graduate courses as well as a reference for professionals, Volume Two's three-part treatment covers mathematical methods, statistical and scheduling studies, and physical phenomena. Contributions include chapters on chance processes and fluctuations by William Feller, Monte Carlo calculati
Modern mathematics for the engineer first series
1956-01-01
This volume and its successor were conceived to advance the level of mathematical sophistication in the engineering community. The books particularly focus on material relevant to solving the kinds of mathematical problems regularly confronted by engineers. Suitable as a text for advanced undergraduate and graduate courses as well as a reference for professionals, Volume One's three-part treatment covers mathematical models, probabilistic problems, and computational considerations. Contributions include chapters on linear and nonlinear oscillations by Solomon Lefschetz, on hyperbolic partial
Mathematical physics applied mathematics for scientists and engineers
Kusse, Bruce R
2006-01-01
What sets this volume apart from other mathematics texts is its emphasis on mathematical tools commonly used by scientists and engineers to solve real-world problems. Using a unique approach, it covers intermediate and advanced material in a manner appropriate for undergraduate students. Based on author Bruce Kusse's course at the Department of Applied and Engineering Physics at Cornell University, Mathematical Physics begins with essentials such as vector and tensor algebra, curvilinear coordinate systems, complex variables, Fourier series, Fourier and Laplace transforms, differential and integral equations, and solutions to Laplace's equations
Heat engine driven by purely quantum information.
Park, Jung Jun; Kim, Kang-Hwan; Sagawa, Takahiro; Kim, Sang Wook
2013-12-06
The key question of this Letter is whether work can be extracted from a heat engine by using purely quantum mechanical information. If the answer is yes, what is its mathematical formula? First, by using a bipartite memory we show that the work extractable from a heat engine is bounded not only by the free energy change and the sum of the entropy change of an individual memory but also by the change of quantum mutual information contained inside the memory. We then find that the engine can be driven by purely quantum information, expressed as the so-called quantum discord, forming a part of the quantum mutual information. To confirm it, as a physical example we present the Szilard engine containing a diatomic molecule with a semipermeable wall.
Life explained by heat engines
Muller, A.W.J.; Seckbach, J.
2012-01-01
Mitochondria are in essence fuel cells that use organics as reductant and oxygen as oxidant. In engineering, increasing attention is being given to the replacement of the internal combustion engine by the fuel cell. According to the Thermosynthesis theory, a similar replacement of heat engines by
Applied mathematics for science and engineering
Glasgow, Larry A
2014-01-01
Prepare students for success in using applied mathematics for engineering practice and post-graduate studies moves from one mathematical method to the next sustaining reader interest and easing the application of the techniques Uses different examples from chemical, civil, mechanical and various other engineering fields Based on a decade's worth of the authors lecture notes detailing the topic of applied mathematics for scientists and engineers Concisely writing with numerous examples provided including historical perspectives as well as a solutions manual for academic adopters
Mathematics and engineering in real life through mathematical competitions
More, M.
2018-02-01
We bring out an experience of organizing mathematical competitions that can be used as a medium to motivate the student and teacher minds in new directions of thinking. This can contribute to fostering research, innovation and provide a hands-on experience of mathematical concepts with the real world. Mathematical competitions can be used to build curiosity and give an understanding of mathematical applications in real life. Participation in the competition has been classified under four broad categories. Student can showcase their findings in various forms of expression like model, poster, soft presentation, animation, live performance, art and poetry. The basic focus of the competition is on using open source computation tools and modern technology, to emphasize the relationship of mathematical concepts with engineering applications in real life.
MATHEMATICAL MODEL OF UNSTEADY HEAT TRANSFER OF PASSENGER CAR WITH HEATING SYSTEM
Directory of Open Access Journals (Sweden)
E. V. Biloshytskyi
2018-02-01
Full Text Available Purpose. The existing mathematical models of unsteady heat processes in a passenger car do not fully reflect the thermal processes, occurring in the car wits a heating system. In addition, unsteady heat processes are often studied in steady regime, when the heat fluxes and the parameters of the thermal circuit are constant and do not depend on time. In connection with the emergence of more effective technical solutions to the life support system there is a need for creating a new mathematical apparatus, which would allow taking into account these features and their influence on the course of unsteady heat processes throughout the travel time. The purpose of this work is to create a mathematical model of the heat regime of a passenger car with a heating system that takes into account the unsteady heat processes. Methodology. To achieve this task the author composed a system of differential equations, describing unsteady heat processes during the heating of a passenger car. For the solution of the composed system of equations, the author used the method of elementary balances. Findings. The paper presents the developed numerical algorithm and computer program for simulation of transitional heat processes in a locomotive traction passenger car, which allows taking into account the various constructive solutions of the life support system of passenger cars and to simulate unsteady heat processes at any stage of the trip. Originality. For the first time the author developed a mathematical model of heat processes in a car with a heating system, that unlike existing models, allows to investigate the unsteady heat engineering performance in the cabin of the car under different operating conditions and compare the work of various life support systems from the point of view their constructive solutions. Practical value. The work presented the developed mathematical model of the unsteady heat regime of the passenger car with a heating system to estimate
Mathematical modeling a chemical engineer's perspective
Rutherford, Aris
1999-01-01
Mathematical modeling is the art and craft of building a system of equations that is both sufficiently complex to do justice to physical reality and sufficiently simple to give real insight into the situation. Mathematical Modeling: A Chemical Engineer's Perspective provides an elementary introduction to the craft by one of the century's most distinguished practitioners.Though the book is written from a chemical engineering viewpoint, the principles and pitfalls are common to all mathematical modeling of physical systems. Seventeen of the author's frequently cited papers are reprinted to illus
Mathematical formulas for industrial and mechanical engineering
Kadry, Seifedine
2014-01-01
Mathematical Formulas For Industrial and Mechanical Engineering serves the needs of students and teachers as well as professional workers in engineering who use mathematics. The contents and size make it especially convenient and portable. The widespread availability and low price of scientific calculators have greatly reduced the need for many numerical tables that make most handbooks bulky. However, most calculators do not give integrals, derivatives, series and other mathematical formulas and figures that are often needed. Accordingly, this book contains that information in an easy way to
MATHEMATICAL MODELING OF UNSTEADY HEAT EXCHANGE IN A PASSENGER CAR
Directory of Open Access Journals (Sweden)
I. Yu. Khomenko
2013-07-01
Full Text Available Purpose.Existing mathematicalmodelsofunsteadyheatexchangeinapassengercardonotsatisfytheneedofthedifferentconstructivedecisionsofthelifesupportsystemefficiencyestimation. They also don’t allow comparing new and old life support system constructions influence on the inner environment conditions. Moreoverquite frequently unsteady heat exchange processes were studied at the initial car motion stage. Due to the new competitive engineering decisionsof the lifesupportsystemthe need of a new mathematical instrument that would satisfy the mentioned features and their influence on the unsteadyheatexchangeprocesses during the whole time of the road appeared. The purpose of this work is creation of the mathematicalmodel ofunsteadyheatexchangeinapassengercarthatcan satisfythe above-listed requirements. Methodology. Fortheassigned task realizationsystemofdifferentialequationsthatcharacterizesunsteadyheatexchangeprocessesinapassengercarwascomposed; forthesystemof equationssolution elementary balance method was used. Findings. Computational algorithm was developed andcomputer program for modeling transitional heat processes in the car was designed. It allows comparing different life support system constructions influence on the inner environment conditionsand unsteady heat exchange processes can be studied at every car motion stage. Originality.Mathematicalmodelofunsteadyheatexchangeinapassengercarwasimproved. That is why it can be used for the heat engineering studying of the inner car state under various conditions and for the operation of the different life support systems of passenger cars comparison. Mathematicalmodelingofunsteadyheatexchangeinapassengercarwas made by the elementary balance method. Practical value. Created mathematical model gives the possibility to simulate temperature changes in passenger car on unsteady thermal conditions with enough accuracy and to introduce and remove additional elements to the designed model. Thus different
International Nuclear Information System (INIS)
Welty, J.R.
1974-01-01
The basic concepts of heat transfer are covered with special emphasis on up-to-date techniques for formulating and solving problems in the field. The discussion progresses logically from phenomenology to problem solving, and treats numerical, integral, and graphical methods as well as traditional analytical ones. The book is unique in its thorough coverage of the fundamentals of numerical analysis appropriate to solving heat transfer problems. This coverage includes several complete and readable examples of numerical solutions, with discussions and interpretations of results. The book also contains an appendix that provides students with physical data for often-encountered materials. An index is included. (U.S.)
Johnson, Clifford V.
2018-02-01
It is shown that aspects of the extended thermodynamic properties of the Taub–Bolt–AdS spacetime in four dimensions are similar to those of the Schwarzschild–AdS black hole. In a high temperature expansion, the equations of state begin to deviate only at next-to-subleading orders. By analogy with what has been done for black holes, Taub–Bolt’s thermodynamic equations are used to define holographic heat engines, the first examples of gravitational heat engines defined using a spacetime that is not a black hole. As a further comparison, the Taub–Bolt engine efficiency is computed for two special kinds of engine cycle and compared to the results for analogous Schwarzschild black hole engine cycles.
An adjustable Brownian heat engine
International Nuclear Information System (INIS)
Asfaw, Mesfin; Bekele, Mulugeta
2002-09-01
A microscopic heat engine is modeled as a Brownian particle in a sawtooth potential (with load) moving through a highly viscous medium driven by the thermal kick it gets from alternately placed hot and cold heat reservoirs. We found a closed form expression for the current as a function of the parameters characterizing the model. Depending on the values these model parameters take, the engine is also found to function as a refrigerator. Expressions for the efficiency as well as for the refrigerator performance are also reported. Study of how these quantities depend on the model parameters enabled us in identifying the points in the parameter space where the engine performs either with maximum power or with optimized efficiency. The corresponding efficiencies of the engine are then compared with those of the endoreversible and Carnot engines. (author)
Probability theory and mathematical statistics for engineers
Pugachev, V S
1984-01-01
Probability Theory and Mathematical Statistics for Engineers focuses on the concepts of probability theory and mathematical statistics for finite-dimensional random variables.The publication first underscores the probabilities of events, random variables, and numerical characteristics of random variables. Discussions focus on canonical expansions of random vectors, second-order moments of random vectors, generalization of the density concept, entropy of a distribution, direct evaluation of probabilities, and conditional probabilities. The text then examines projections of random vector
Mathematical methods for physicists and engineers
Collins, Royal Eugene
2011-01-01
This practical, highly readable text provides physics and engineering students with the essential mathematical tools for thorough comprehension of their disciplines. Featuring all the necessary topics in applied mathematics in the form of programmed instruction, the text can be understood by advanced undergraduates and beginning graduate students without any assistance from the instructor. Topics include elementary vector calculus, matrix algebra, and linear vector operations; the many and varied methods of solving linear boundary value problems, including the more common special functions o
Annaratone, Donatello
2010-01-01
This book is a generalist textbook; it is designed for anybody interested in heat transmission, including scholars, designers and students. Two criteria constitute the foundation of Annaratone's books, including the present one. The first one consists of indispensable scientific rigor without theoretical exasperation. The inclusion in the book of some theoretical studies, even if admirable for their scientific rigor, would have strengthened the scientific foundation of this publication, yet without providing the reader with further applicable know-how. The second criterion is to deliver practi
Mathematical Modeling of Loop Heat Pipes
Kaya, Tarik; Ku, Jentung; Hoang, Triem T.; Cheung, Mark L.
1998-01-01
The primary focus of this study is to model steady-state performance of a Loop Heat Pipe (LHP). The mathematical model is based on the steady-state energy balance equations at each component of the LHP. The heat exchange between each LHP component and the surrounding is taken into account. Both convection and radiation environments are modeled. The loop operating temperature is calculated as a function of the applied power at a given loop condition. Experimental validation of the model is attempted by using two different LHP designs. The mathematical model is tested at different sink temperatures and at different elevations of the loop. Tbc comparison of the calculations and experimental results showed very good agreement (within 3%). This method proved to be a useful tool in studying steady-state LHP performance characteristics.
Mathematics for engineering, technology and computing science
Martin, Hedley G
1970-01-01
Mathematics for Engineering, Technology and Computing Science is a text on mathematics for courses in engineering, technology, and computing science. It covers linear algebra, ordinary differential equations, and vector analysis, together with line and multiple integrals. This book consists of eight chapters and begins with a discussion on determinants and linear equations, with emphasis on how the value of a determinant is defined and how it may be obtained. Solution of linear equations and the dependence between linear equations are also considered. The next chapter introduces the reader to
Mathematical Building-Blocks in Engineering Mechanics
Boyajian, David M.
2007-01-01
A gamut of mathematical subjects and concepts are taught within a handful of courses formally required of the typical engineering student who so often questions the relevancy of being bound to certain lower-division prerequisites. Basic classes at the undergraduate level, in this context, include: Integral and Differential Calculus, Differential…
MATHEMATICAL MODELING OF HEATING RATE PRODUCT AT HIGH HEAT TREATMENT
Directory of Open Access Journals (Sweden)
M. M. Akhmedova
2014-01-01
Full Text Available Methods of computing and mathematical modeling are all widely used in the study of various heat exchange processes that provide the ability to study the dynamics of the processes, as well as to conduct a reasonable search for the optimal technological parameters of heat treatment.This work is devoted to the identification of correlations among the factors that have the greatest effect on the rate of heating of the product at hightemperature heat sterilization in a stream of hot air, which are chosen as the temperature difference (between the most and least warming up points and speed cans during heat sterilization.As a result of the experimental data warming of the central and peripheral layers compote of apples in a 3 liter pot at high-temperature heat treatment in a stream of hot air obtained by the regression equation in the form of a seconddegree polynomial, taking into account the effects of pair interaction of these parameters.
Applied mathematics for engineers and physicists
Pipes, Louis A
2014-01-01
One of the most widely used reference books on applied mathematics for a generation, distributed in multiple languages throughout the world, this text is geared toward use with a one-year advanced course in applied mathematics for engineering students. The treatment assumes a solid background in the theory of complex variables and a familiarity with complex numbers, but it includes a brief review. Chapters are as self-contained as possible, offering instructors flexibility in designing their own courses. The first eight chapters explore the analysis of lumped parameter systems. Succeeding topi
Heat Pipes Reduce Engine-Exhaust Emissions
Schultz, D. F.
1986-01-01
Increased fuel vaporization raises engine efficiency. Heat-pipe technology increased efficiency of heat transfer beyond that obtained by metallic conduction. Resulted in both improved engine operation and reduction in fuel consumption. Raw material conservation through reduced dependence on strategic materials also benefit from this type of heat-pipe technology. Applications result in improved engine performance and cleaner environment.
Performance of heat engines with non-zero heat capacity
International Nuclear Information System (INIS)
Odes, Ron; Kribus, Abraham
2013-01-01
Highlights: ► Finite heat capacity is a second irreversibility mechanism in addition to thermal resistance. ► Heat capacity introduces thermal transients and reverse heat flow. ► Engine maximum power and efficiency are lower for finite heat capacity. ► Implementing the optimal engine cycle requires active control. - Abstract: The performance of a heat engine is analyzed subject to two types of irreversibility: a non-zero heat capacity, together with the more common finite heat transfer rate between the engine and the external heat reservoirs. The heat capacity represents an engine body that undergoes significant temperature variations during the engine cycle. An option to cut off the heat exchange between the engine and the external surrounding for part of the engine cycle is also explored. A variational approach was taken to find the engine’s internal temperature profile (which defines the internal thermodynamic cycle) that would produce maximum power. The maximum power is shown to be lower than the case of zero heat capacity, due to a loss of heat that is stored in the engine body and then lost, bypassing the thermodynamic cycle. The maximum efficiency and the efficiency at maximum power are also lower than the zero heat capacity case. Similar to the Curzon–Ahlborn analysis, power can be traded for increased efficiency, but for high heat capacity, the range of efficiency that is available for such a trade is diminished. Isolating the engine during part of the cycle reduces maximum power, but the efficiency at maximum power and the maximum efficiency are improved, due to better exploitation of heat stored in the engine body. This might be useful for real engines that are limited by the internal energy change during a single engine cycle or by the operating frequency, leading to a broader power–efficiency curve.
Combination solar photovoltaic heat engine energy converter
Chubb, Donald L.
1987-01-01
A combination solar photovoltaic heat engine converter is proposed. Such a system is suitable for either terrestrial or space power applications. The combination system has a higher efficiency than either the photovoltaic array or the heat engine alone can attain. Advantages in concentrator and radiator area and receiver mass of the photovoltaic heat engine system over a heat-engine-only system are estimated. A mass and area comparison between the proposed space station organic Rankine power system and a combination PV-heat engine system is made. The critical problem for the proposed converter is the necessity for high temperature photovoltaic array operation. Estimates of the required photovoltaic temperature are presented.
Students' perceptions of the relevance of mathematics in engineering
Flegg, Jennifer; Mallet, Dann; Lupton, Mandy
2012-09-01
In this article, we report on the findings of an exploratory study into the experience of students as they learn first year engineering mathematics. Here we define engineering as the application of mathematics and sciences to the building and design of projects for the use of society [M. Kirschenman and B. Brenner, Education for Civil Engineering: A Profession of Practice, Leader. Manag. Eng. 10 (2010), p. 54]. Qualitative and quantitative data on students' views of the relevance of their mathematics study to their engineering studies and future careers in engineering was collected. The students described using a range of mathematics techniques (mathematics skills developed, mathematics concepts applied to engineering and skills developed relevant for engineering) for various usages (as a subject of study, a tool for other subjects or a tool for real world problems). We found a number of themes relating to the design of engineering mathematics curriculum emerged from the data. These included the relevance of mathematics within different engineering majors, the relevance of mathematics to future studies, the relevance of learning mathematical rigour and the effectiveness of problem-solving tasks in conveying the relevance of mathematics more effectively than other forms of assessment. We make recommendations for the design of engineering mathematics curriculum based on our findings.
Adaptation of abbreviated mathematics anxiety rating scale for engineering students
Nordin, Sayed Kushairi Sayed; Samat, Khairul Fadzli; Sultan, Al Amin Mohamed; Halim, Bushra Abdul; Ismail, Siti Fatimah; Mafazi, Nurul Wirdah
2015-05-01
Mathematics is an essential and fundamental tool used by engineers to analyse and solve problems in their field. Due to this, most engineering education programs involve a concentration of study in mathematics courses whereby engineering students have to take mathematics courses such as numerical methods, differential equations and calculus in the first two years and continue to do so until the completion of the sequence. However, the students struggled and had difficulties in learning courses that require mathematical abilities. Hence, this study presents the factors that caused mathematics anxiety among engineering students using Abbreviated Mathematics Anxiety Rating Scale (AMARS) through 95 students of Universiti Teknikal Malaysia Melaka (UTeM). From 25 items in AMARS, principal component analysis (PCA) suggested that there are four mathematics anxiety factors, namely experiences of learning mathematics, cognitive skills, mathematics evaluation anxiety and students' perception on mathematics. Minitab 16 software was used to analyse the nonparametric statistics. Kruskal-Wallis Test indicated that there is a significant difference in the experience of learning mathematics and mathematics evaluation anxiety among races. The Chi-Square Test of Independence revealed that the experience of learning mathematics, cognitive skills and mathematics evaluation anxiety depend on the results of their SPM additional mathematics. Based on this study, it is recommended to address the anxiety problems among engineering students at the early stage of studying in the university. Thus, lecturers should play their part by ensuring a positive classroom environment which encourages students to study mathematics without fear.
Mathematical Model of Piston Ring Sealing in Combustion Engine
Directory of Open Access Journals (Sweden)
Koszałka Grzegorz
2015-01-01
Full Text Available This paper presents a mathematical model of piston-rings-cylinder sealing (TPC of a combustion engine. The developed model is an itegrated model of gas flow through gaps in TPC unit, displacements and twisting motions of piston rings in ring grooves as well as generation of oil film between ring face surfaces and cylinder liner. Thermal deformations and wear of TPC unit elements as well as heat exchange between flowing gas and surrounding walls, were taken into account in the model. The paper contains descriptions of: assumptions used for developing the model, the model itself, its numerical solution as well as its computer application for carrying out simulation tests.
The Role of Mathematics Learning Centres in Engineering Education.
Fuller, Milton
2002-01-01
Points out the diminishing demand for mathematics undergraduate programs and the strong trend in engineering education to make greater use of computer coursework such as Mathcad, Matlab, and other software systems for the mathematical and statistical components of engineering programs. Describes the changing role of mathematics learning centers…
Mathematical methods in physics and engineering
Dettman, John W
2011-01-01
Intended for college-level physics, engineering, or mathematics students, this volume offers an algebraically based approach to various topics in applied math. It is accessible to undergraduates with a good course in calculus which includes infinite series and uniform convergence. Exercises follow each chapter to test the student's grasp of the material; however, the author has also included exercises that extend the results to new situations and lay the groundwork for new concepts to be introduced later. A list of references for further reading will be found at the end of each chapter. For t
Formative assessment in mathematics for engineering students
Ní Fhloinn, Eabhnat; Carr, Michael
2017-07-01
In this paper, we present a range of formative assessment types for engineering mathematics, including in-class exercises, homework, mock examination questions, table quizzes, presentations, critical analyses of statistical papers, peer-to-peer teaching, online assessments and electronic voting systems. We provide practical tips for the implementation of such assessments, with a particular focus on time or resource constraints and large class sizes, as well as effective methods of feedback. In addition, we consider the benefits of such formative assessments for students and staff.
Mathematical and Scientific Foundations for an Integrative Engineering Curriculum.
Carr, Robin; And Others
1995-01-01
Describes the Mathematical and Scientific Foundations of Engineering curriculum which emphasizes the mathematical and scientific concepts common to all engineering fields. Scientists and engineers together devised topics and experiments that emphasize the relevance of theory to real-world applications. Presents material efficiently while building…
Surface engineering and heat treatment
International Nuclear Information System (INIS)
Morton, P.H.
1991-01-01
This book is the proceedings of a Conference organised jointly by The Institute of Metals and The Centre for Exploitation of Science and Technology (CEST). It sets out to review this role and point the way to the future by collecting together a series of invited papers written by noted authorities in their fields. The opening review by CEST highlights the economic and industrial importance of Surface Engineering and is followed by a group of four articles devoted to specific branches of industry. Several technical papers then describe various aspects of the development of heat treatment over the last twenty-five years. These are followed by papers describing advances made possible by new technologies such as plasma, laser and ion beam. A separate abstract has been prepared for a paper on materials aspects of ion beam technology. (author)
Learning mathematics in students of Mechanical Engineering
Directory of Open Access Journals (Sweden)
Raquel Ramírez-Pedroso
2016-07-01
Full Text Available Mathematical discipline contributes to the development of logical and algorithmic thinking and provides the basics of a specialist in Technical Sciences, as every engineer considers technical and scientific representations in mathematical terms, with which reflects the quantitative and qualitative features of the phenomena studied . His goal is to make the engineer master the mathematical apparatus to do so able to model and analyze the technical, economic, productive and scientific processes using both, analytical methods and numerical. Interdisciplinarity is a current educational trend that puts in the center the comprehensive treatment of the complex processes of reality from the contribution of different disciplines and meet common objectives. It is necessary to address the issue of interdisciplinarity, from different points of view. Normal 0 21 false false false ES X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}
Novikov Engine with Fluctuating Heat Bath Temperature
Schwalbe, Karsten; Hoffmann, Karl Heinz
2018-04-01
The Novikov engine is a model for heat engines that takes the irreversible character of heat fluxes into account. Using this model, the maximum power output as well as the corresponding efficiency of the heat engine can be deduced, leading to the well-known Curzon-Ahlborn efficiency. The classical model assumes constant heat bath temperatures, which is not a reasonable assumption in the case of fluctuating heat sources. Therefore, in this article the influence of stochastic fluctuations of the hot heat bath's temperature on the optimal performance measures is investigated. For this purpose, a Novikov engine with fluctuating heat bath temperature is considered. Doing so, a generalization of the Curzon-Ahlborn efficiency is found. The results can help to quantify how the distribution of fluctuating quantities affects the performance measures of power plants.
Mathematics and Engineering in Real Life through Mathematical Competitions
More, M.
2018-01-01
We bring out an experience of organizing mathematical competitions that can be used as a medium to motivate the student and teacher minds in new directions of thinking. This can contribute to fostering research, innovation and provide a hands-on experience of mathematical concepts with the real world. Mathematical competitions can be used to build…
Heat Exchanger Lab for Chemical Engineering Undergraduates
Rajala, Jonathan W.; Evans, Edward A.; Chase, George G.
2015-01-01
Third year chemical engineering undergraduate students at The University of Akron designed and fabricated a heat exchanger for a stirred tank as part of a Chemical Engineering Laboratory course. The heat exchanger portion of this course was three weeks of the fifteen week long semester. Students applied concepts of scale-up and dimensional…
Shalaginova, Z. I.
2016-03-01
The mathematical model and calculation method of the thermal-hydraulic modes of heat points, based on the theory of hydraulic circuits, being developed at the Melentiev Energy Systems Institute are presented. The redundant circuit of the heat point was developed, in which all possible connecting circuits (CC) of the heat engineering equipment and the places of possible installation of control valve were inserted. It allows simulating the operating modes both at central heat points (CHP) and individual heat points (IHP). The configuration of the desired circuit is carried out automatically by removing the unnecessary links. The following circuits connecting the heating systems (HS) are considered: the dependent circuit (direct and through mixing elevator) and independent one (through the heater). The following connecting circuits of the load of hot water supply (HWS) were considered: open CC (direct water pumping from pipelines of heat networks) and a closed CC with connecting the HWS heaters on single-level (serial and parallel) and two-level (sequential and combined) circuits. The following connecting circuits of the ventilation systems (VS) were also considered: dependent circuit and independent one through a common heat exchanger with HS load. In the heat points, water temperature regulators for the hot water supply and ventilation and flow regulators for the heating system, as well as to the inlet as a whole, are possible. According to the accepted decomposition, the model of the heat point is an integral part of the overall heat-hydraulic model of the heat-supplying system having intermediate control stages (CHP and IHP), which allows to consider the operating modes of the heat networks of different levels connected with each other through CHP as well as connected through IHP of consumers with various connecting circuits of local systems of heat consumption: heating, ventilation and hot water supply. The model is implemented in the Angara data
Advanced radioisotope heat source for Stirling Engines
International Nuclear Information System (INIS)
Dobry, T.J.; Walberg, G.
2001-01-01
The heat exchanger on a Stirling Engine requires a thermal energy transfer from a heat source to the engine through a very limited area on the heater head circumference. Designing an effective means to assure maximum transfer efficiency is challenging. A single General Purpose Heat Source (GPHS), which has been qualified for space operations, would satisfy thermal requirements for a single Stirling Engine that would produce 55 electrical watts. However, it is not efficient to transfer its thermal energy to the engine heat exchanger from its rectangular geometry. This paper describes a conceptual design of a heat source to improve energy transfer for Stirling Engines that may be deployed to power instrumentation on space missions
Science, Engineering, Mathematics and Aerospace Academy
1997-01-01
This is an annual report on the Science, Engineering, Mathematics, and Aerospace Academy (SEMAA), which is run as a collaborative effort of NASA Lewis Research Center, and Cuyahgoga Community College. The purpose of SEMA is to increase the percentage of African Americans, and Hispanics in the fields of science and technology. The SEMAA program reaches from kindergarden, to grade 12, involving the family of under-served minorities in the education of the children. The year being reported (i.e., 1996-1997) saw considerable achievement. The program served over 1,939 students, and 120 parents were involved in various seminars. The report goes on to review the program and its implementation for each grade level. It also summarizes the participation, by gender and ethnicity.
MATHEMATICAL MODELING OF HEATING AND COOLING OF SAUSAGES
Directory of Open Access Journals (Sweden)
A. V. Zhuchkov
2013-01-01
Full Text Available In the article the mathematical modeling of the processes of heating and cooling of sausage products in order to define reference characteristics of the processes was carried out. Basic regularities of the processes are graphically shown.
Mathematical Modeling of Hybrid Electrical Engineering Systems
Directory of Open Access Journals (Sweden)
A. A. Lobaty
2016-01-01
Full Text Available A large class of systems that have found application in various industries and households, electrified transportation facilities and energy sector has been classified as electrical engineering systems. Their characteristic feature is a combination of continuous and discontinuous modes of operation, which is reflected in the appearance of a relatively new term “hybrid systems”. A wide class of hybrid systems is pulsed DC converters operating in a pulse width modulation, which are non-linear systems with variable structure. Using various methods for linearization it is possible to obtain linear mathematical models that rather accurately simulate behavior of such systems. However, the presence in the mathematical models of exponential nonlinearities creates considerable difficulties in the implementation of digital hardware. The solution can be found while using an approximation of exponential functions by polynomials of the first order, that, however, violates the rigor accordance of the analytical model with characteristics of a real object. There are two practical approaches to synthesize algorithms for control of hybrid systems. The first approach is based on the representation of the whole system by a discrete model which is described by difference equations that makes it possible to synthesize discrete algorithms. The second approach is based on description of the system by differential equations. The equations describe synthesis of continuous algorithms and their further implementation in a digital computer included in the control loop system. The paper considers modeling of a hybrid electrical engineering system using differential equations. Neglecting the pulse duration, it has been proposed to describe behavior of vector components in phase coordinates of the hybrid system by stochastic differential equations containing generally non-linear differentiable random functions. A stochastic vector-matrix equation describing dynamics of the
Zero-dimensional mathematical model of the torch ignited engine
International Nuclear Information System (INIS)
Cruz, Igor William Santos Leal; Alvarez, Carlos Eduardo Castilla; Teixeira, Alysson Fernandes; Valle, Ramon Molina
2016-01-01
Highlights: • Publications about the torch ignition system are mostly CFD or experimental research. • A zero-dimensional mathematical model is presented. • The model is based on classical thermodynamic equations. • Approximations are based on empirical functions. • The model is applied to a prototype by means of a computer code. - Abstract: Often employed in the analysis of conventional SI and CI engines, mathematical models can also be applied to engines with torch ignition, which have been researched almost exclusively by CFD or experimentally. The objective of this work is to describe the development and application of a zero-dimensional model of the compression and power strokes of a torch ignited engine. It is an initial analysis that can be used as a basis for future models. The processes of compression, combustion and expansion were described mathematically and applied to an existing prototype by means of a computer code written in MATLAB language. Conservation of energy and mass and the ideal gas law were used in determining gas temperature, pressure, and mass flow rate within the cylinder. Gas motion through the orifice was modelled as an isentropic compressible flow. The thermodynamic properties of the mixture were found by a weighted arithmetic mean of the data for each component, computed by polynomial functions of temperature. Combustion was modelled by the Wiebe function. Heat transfer to the cylinder walls was estimated by Annand’s correlations. Results revealed the behaviour of pressure, temperature, jet velocity, energy transfer, thermodynamic properties, among other variables, and how some of these are influenced by others.
Students' Perceptions of the Relevance of Mathematics in Engineering
Flegg, Jennifer; Mallet, Dann; Lupton, Mandy
2012-01-01
In this article, we report on the findings of an exploratory study into the experience of students as they learn first year engineering mathematics. Here we define engineering as the application of mathematics and sciences to the building and design of projects for the use of society [M. Kirschenman and B. Brenner, "Education for Civil…
MATHEMATICAL MODEL OF UNSTEADY HEAT TRANSFER OF PASSENGER CAR WITH HEATING SYSTEM
E. V. Biloshytskyi
2018-01-01
Purpose. The existing mathematical models of unsteady heat processes in a passenger car do not fully reflect the thermal processes, occurring in the car wits a heating system. In addition, unsteady heat processes are often studied in steady regime, when the heat fluxes and the parameters of the thermal circuit are constant and do not depend on time. In connection with the emergence of more effective technical solutions to the life support system there is a need for creating a new mathematical...
The use of mathematical models in teaching wastewater treatment engineering
DEFF Research Database (Denmark)
Morgenroth, Eberhard Friedrich; Arvin, Erik; Vanrolleghem, P.
2002-01-01
Mathematical modeling of wastewater treatment processes has become increasingly popular in recent years. To prepare students for their future careers, environmental engineering education should provide students with sufficient background and experiences to understand and apply mathematical models...... efficiently and responsibly. Approaches for introducing mathematical modeling into courses on wastewater treatment engineering are discussed depending on the learning objectives, level of the course and the time available....
D. Shchedrolosev
2010-01-01
Fundamental mathematical background is an important part of training future engineers and programmers. The paper considers existing approaches to teaching the fundamentals of discrete mathematics specialist IT profile, a comparative analysis of modern textbooks on discrete mathematics for IT professionals was conducted
Directory of Open Access Journals (Sweden)
D. Shchedrolosev
2010-04-01
Full Text Available Fundamental mathematical background is an important part of training future engineers and programmers. The paper considers existing approaches to teaching the fundamentals of discrete mathematics specialist IT profile, a comparative analysis of modern textbooks on discrete mathematics for IT professionals was conducted
Reverse electrodialysis heat engine for sustainable power production
International Nuclear Information System (INIS)
Tamburini, A.; Tedesco, M.; Cipollina, A.; Micale, G.; Ciofalo, M.; Papapetrou, M.; Van Baak, W.; Piacentino, A.
2017-01-01
Graphical abstract: State of the art technologies for the conversion of heat into power. Grey circles refer to technologies at very early stage of development and non-available at industrial level. The Carnot efficiency (on the secondary horizontal axis) is evaluated assuming a cold sink temperature of 25 °C. SRC-hot gases: Steam Rankine Cycle integrated with gas turbine/other topping cycles; SRC-fuel: Steam Rankine Cycle directly fuelled by oil, coal or other fuels; KC: Kalina Cycle; ORC: Organic Rankine Cycle; TEG: Thermoelectric Generation; PEPG: Piezoelectric Power Generation with waste heat-powered expansion/compression cycle; OHE: Osmotic Heat Engine; REDHE, Reverse Electrodialysis Heat Engine (this paper). Display Omitted -- Highlights: •For the first time, the potential of Reverse Electrodialysis Heat Engine is assessed. •An overview of the possible regeneration methods is presented. •Performance of the RED unit fed by different salty solutions was suitably optimized. •Three different RED Heat Engine scenarios were studied. •Exergetic efficiency of about 85% could be achieved in the foreseen future. -- Abstract: Reverse Electrodialysis Heat Engine (REDHE) is a promising technology to convert waste heat at temperatures lower than 100 °C into electric power. In the present work an overview of the possible regeneration methods is presented and the technological challenges for the development of the RED Heat Engine (REDHE) are identified. The potential of this power production cycle was investigated through a simplified mathematical model. In the first part of the work, several salts were singularly modelled as possible solutes in aqueous solutions feeding the RED unit and the corresponding optimal conditions were recognized via an optimization study. In the second part, three different RED Heat Engine scenarios were studied. Results show that power densities much higher than those relevant to NaCl-water solutions can be obtained by using different
MODERN OR TRADITIONAL TEACHING STRATEGY IN LEARNING ENGINEERING MATHEMATICS COURSE
Directory of Open Access Journals (Sweden)
N. RAZALI
2016-11-01
Full Text Available First-year engineering students of the Faculty of Engineering and Built Environment, UKM are in the process of transition in the way they learn mathematics from pre-university level to the undergraduate level. It is essential for good engineers to have the ability to unfold mathematical problems in an efficient way. Thus, this research is done to investigate students preference in learning KKKQ1123 Engineering Mathematics I (Vector Calculus (VC course; either individually or in a team; using modern (e-learning or traditional (cooperative-learning teaching strategy. Questionnaires are given to the first year Chemical and Process Engineering students from academic year 2015/2016 and the results were analysed. Based on the finding, the students believed that the physical educators or teachers play an important role and that they have slightest preference in the traditional teaching strategy to learn engineering mathematics course.
Reliability of ceramics for heat engine applications
1980-01-01
The advantages and disadvantages associated with the use of monolithic ceramics in heat engines are discussed. The principle gaps in the state of understanding of ceramic material, failure origins, nondestructive tests as well as life prediction are included.
Stirling Engine With Radial Flow Heat Exchangers
Vitale, N.; Yarr, George
1993-01-01
Conflict between thermodynamical and structural requirements resolved. In Stirling engine of new cylindrical configuration, regenerator and acceptor and rejector heat exchangers channel flow of working gas in radial direction. Isotherms in regenerator ideally concentric cylinders, and gradient of temperature across regenerator radial rather than axial. Acceptor and rejector heat exchangers located radially inward and outward of regenerator, respectively. Enables substantial increase in power of engine without corresponding increase in diameter of pressure vessel.
Mathematical Modelling of a Hybrid Micro-Cogeneration Group Based on a Four Stroke Diesel Engine
Directory of Open Access Journals (Sweden)
Apostol Valentin
2014-06-01
Full Text Available The paper presents a part of the work conducted in the first stage of a Research Grant called ”Hybrid micro-cogeneration group of high efficiency equipped with an electronically assisted ORC” acronym GRUCOHYB. The hybrid micro-cogeneration group is equipped with a four stroke Diesel engine having a maximum power of 40 kW. A mathematical model of the internal combustion engine is presented. The mathematical model is developed based on the Laws of Thermodynamics and takes into account the real, irreversible processes. Based on the mathematical model a computation program was developed. The results obtained were compared with those provided by the Diesel engine manufacturer. Results show a very high correlation between the manufacturer’s data and the simulation results for an engine running at 100% load. Future developments could involve using an exergetic analysis to show the ability of the ORC to generate electricity from recovered heat
Which Techno-mathematical Literacies Are Essential for Future Engineers?
van der Wal, Nathalie J.; Bakker, Arthur; Drijvers, Paul
Due to increased use of technology, the workplace practices of engineers have changed. So-called techno-mathematical literacies (TmL) are necessary for engineers of the 21st century. Because it is still unknown which TmL engineers actually use in their professional practices, the purpose of this
Engineering calculations in radiative heat transfer
Gray, W A; Hopkins, D W
1974-01-01
Engineering Calculations in Radiative Heat Transfer is a six-chapter book that first explains the basic principles of thermal radiation and direct radiative transfer. Total exchange of radiation within an enclosure containing an absorbing or non-absorbing medium is then described. Subsequent chapters detail the radiative heat transfer applications and measurement of radiation and temperature.
Efficiency bounds for nonequilibrium heat engines
International Nuclear Information System (INIS)
Mehta, Pankaj; Polkovnikov, Anatoli
2013-01-01
We analyze the efficiency of thermal engines (either quantum or classical) working with a single heat reservoir like an atmosphere. The engine first gets an energy intake, which can be done in an arbitrary nonequilibrium way e.g. combustion of fuel. Then the engine performs the work and returns to the initial state. We distinguish two general classes of engines where the working body first equilibrates within itself and then performs the work (ergodic engine) or when it performs the work before equilibrating (non-ergodic engine). We show that in both cases the second law of thermodynamics limits their efficiency. For ergodic engines we find a rigorous upper bound for the efficiency, which is strictly smaller than the equivalent Carnot efficiency. I.e. the Carnot efficiency can be never achieved in single reservoir heat engines. For non-ergodic engines the efficiency can be higher and can exceed the equilibrium Carnot bound. By extending the fundamental thermodynamic relation to nonequilibrium processes, we find a rigorous thermodynamic bound for the efficiency of both ergodic and non-ergodic engines and show that it is given by the relative entropy of the nonequilibrium and initial equilibrium distributions. These results suggest a new general strategy for designing more efficient engines. We illustrate our ideas by using simple examples. -- Highlights: ► Derived efficiency bounds for heat engines working with a single reservoir. ► Analyzed both ergodic and non-ergodic engines. ► Showed that non-ergodic engines can be more efficient. ► Extended fundamental thermodynamic relation to arbitrary nonequilibrium processes
Mathematical modeling and computational intelligence in engineering applications
Silva Neto, Antônio José da; Silva, Geraldo Nunes
2016-01-01
This book brings together a rich selection of studies in mathematical modeling and computational intelligence, with application in several fields of engineering, like automation, biomedical, chemical, civil, electrical, electronic, geophysical and mechanical engineering, on a multidisciplinary approach. Authors from five countries and 16 different research centers contribute with their expertise in both the fundamentals and real problems applications based upon their strong background on modeling and computational intelligence. The reader will find a wide variety of applications, mathematical and computational tools and original results, all presented with rigorous mathematical procedures. This work is intended for use in graduate courses of engineering, applied mathematics and applied computation where tools as mathematical and computational modeling, numerical methods and computational intelligence are applied to the solution of real problems.
Externally heated valve engine a new approach to piston engines
Kazimierski, Zbyszko
2016-01-01
This book reports on a novel approach for generating mechanical energy from different, external heat sources using the body of a typical piston engine with valves. By presenting simple yet effective numerical models, the authors show how this new approach, which combines existing internal combustion technology with a lubrication system, is able to offer an economic solution to the problem of mechanical energy generation in piston engines. Their results also show that a stable heat generation process can be guaranteed outside of the engine. The book offers a detailed report on physical and numerical models of 4-stroke and 2-stroke versions of the EHVE together with different models of heat exchange, valves and results of their simulations. It also delivers the test results of an engine prototype run in laboratory conditions. By presenting a novel theoretical framework and providing readers with extensive knowledge of both the advantages and challenges of the method, this book is expected to inspire academic re...
Technology-Enhanced Mathematics Education for Creative Engineering Studies
DEFF Research Database (Denmark)
Triantafyllou, Eva; Timcenko, Olga
2014-01-01
This project explores the opportunities and challenges of integrating digital technologies in mathematics education in creative engineering studies. Students in such studies lack motivation and do not perceive the mathematics the same way as mathematics students do. Digital technologies offer new...... are conceptualized. Then, we are going to apply this field data in designing learning technologies, which will be introduced in university classrooms. The effect of this introduction will be evaluated through educational design experiments....
A Mathematics Support Programme for First-Year Engineering Students
Hillock, Poh Wah; Jennings, Michael; Roberts, Anthony; Scharaschkin, Victor
2013-01-01
This article describes a mathematics support programme at the University of Queensland, targeted at first-year engineering students identified as having a high risk of failing a first-year mathematics course in calculus and linear algebra. It describes how students were identified for the programme and the main features of the programme. The…
Support of Study on Engineering Technology from Physics and Mathematics
Mynbaev, Djafar K.; Cabo, Candido; Kezerashvili, Roman Ya.; Liou-Mark, Janet
2008-01-01
An approach that provides students with an ability to transfer learning in physics and mathematics to the engineering-technology courses through e-teaching and e-learning process is proposed. E-modules of courses in mathematics, physics, computer systems technology, and electrical and telecommunications engineering technology have been developed. These modules being used in the Blackboard and Web-based communications systems create a virtual interdisciplinary learning community, which helps t...
Heat pump heating with heat pumps driven by combustion engines or turbines
Energy Technology Data Exchange (ETDEWEB)
Hein, K
1977-01-27
The heat pump described is driven by a gas Otto cycle engine, or a gas- or light- or heavy-oil fired Diesel engine. The claim refers to the use of waste heat of the engines by feeding into the input circuit of the heat pump. In addition, a drive by an electrical motor-generator or power production can be selected at times of peak load in the electrical supply network.
Basitere, Moses; Ivala, Eunice
2015-01-01
This paper reports on a study carried out at a University of Technology, South Africa, aimed at identifying the existence of the mathematical knowledge gap and evaluating the intervention designed to bridge the knowledge gap amongst students studying first year mathematics at the Chemical Engineering Extended Curriculum Program (ECP). In this…
Computer-Based Mathematics Instructions for Engineering Students
Khan, Mustaq A.; Wall, Curtiss E.
1996-01-01
Almost every engineering course involves mathematics in one form or another. The analytical process of developing mathematical models is very important for engineering students. However, the computational process involved in the solution of some mathematical problems may be very tedious and time consuming. There is a significant amount of mathematical software such as Mathematica, Mathcad, and Maple designed to aid in the solution of these instructional problems. The use of these packages in classroom teaching can greatly enhance understanding, and save time. Integration of computer technology in mathematics classes, without de-emphasizing the traditional analytical aspects of teaching, has proven very successful and is becoming almost essential. Sample computer laboratory modules are developed for presentation in the classroom setting. This is accomplished through the use of overhead projectors linked to graphing calculators and computers. Model problems are carefully selected from different areas.
Ceramic Technology for Advanced Heat Engines Project
Energy Technology Data Exchange (ETDEWEB)
1989-08-01
The Ceramic Technology for Advanced Heat Engines Project was developed by the Department of Energy's Office of Transportation Systems (OTS) in Conservation and Renewable Energy. This project, part of the OTS's Advanced Materials Development Program, was developed to meet the ceramic technology requirements of the OTS's automotive technology programs. Significant accomplishments in fabricating ceramic components for the Department of Energy (DOE), National Aeronautics and Space Administration (NASA), and Department of Defense (DoD) advanced heat engine programs have provided evidence that the operation of ceramic parts in high-temperature engine environments is feasible. However, these programs have also demonstrated that additional research is needed in materials and processing development, design methodology, and data base and life prediction before industry will have a sufficient technology base from which to produce reliable cost-effective ceramic engine components commercially.
Colloquy on Minority Males in Science, Technology, Engineering, and Mathematics
Didion, Catherine; Fortenberry, Norman L.; Cady, Elizabeth
2012-01-01
On August 8-12, 2010 the National Academy of Engineering (NAE), with funding from the National Science Foundation (NSF), convened the Colloquy on Minority Males in Science, Technology, Engineering, and Mathematics (STEM), following the release of several reports highlighting the educational challenges facing minority males. The NSF recognized the…
Mathematics Learning by Programming in a Game Engine
DEFF Research Database (Denmark)
Triantafyllou, Evangelia; Timcenko, Olga; Misfeldt, Morten
2017-01-01
This paper emerges from our research focusing on mathematics education in trans-disciplinary engineering programs and presents a case study in such an engineering discipline, namely the Media Technology program at Aalborg University Copenhagen, Denmark. In this case study, we substituted traditio...
Ceramic Technology For Advanced Heat Engines Project
Energy Technology Data Exchange (ETDEWEB)
1990-12-01
Significant accomplishments in fabricating ceramic components for the Department of Energy (DOE), National Aeronautics and Space Administration (NASA), and Department of Defense (DoD) advanced heat engine programs have provided evidence that the operation of ceramic parts in high-temperature engine environments is feasible. However, these programs have also demonstrated that additional research is needed in materials and processing development, design methodology, and data base and life prediction before industry will have a sufficient technology base from which to produce reliable cost-effective ceramic engine components commercially. The objective of the project is to develop the industrial technology base required for reliable ceramics for application in advanced automotive heat engines. The project approach includes determining the mechanisms controlling reliability, improving processes for fabricating existing ceramics, developing new materials with increased reliability, and testing these materials in simulated engine environments to confirm reliability. Although this is a generic materials project, the focus is on the structural ceramics for advanced gas turbine and diesel engines, ceramic bearings and attachments, and ceramic coatings for thermal barrier and wear applications in these engines. This advanced materials technology is being developed in parallel and close coordination with the ongoing DOE and industry proof of concept engine development programs. To facilitate the rapid transfer of this technology to U.S. industry, the major portion of the work is being done in the ceramic industry, with technological support from government laboratories, other industrial laboratories, and universities. Abstracts prepared for appropriate papers.
Quantum heat engine with coupled superconducting resonators
DEFF Research Database (Denmark)
Hardal, Ali Ümit Cemal; Aslan, Nur; Wilson, C. M.
2017-01-01
We propose a quantum heat engine composed of two superconducting transmission line resonators interacting with each other via an optomechanical-like coupling. One resonator is periodically excited by a thermal pump. The incoherently driven resonator induces coherent oscillations in the other one...... the signatures of quantum behavior in the statistical and thermodynamic properties of the system. We find evidence of a quantum enhancement in the power output of the engine at low temperatures....
Milaturrahmah, Naila; Mardiyana, Pramudya, Ikrar
2017-08-01
This 21st century demands competent human resources in science, technology, engineering design and mathematics so that education is expected to integrate the four disciplines. This paper aims to describe the importance of STEM as mathematics learning approach in Indonesia in the 21st century. This paper uses a descriptive analysis research method, and the method reveals that STEM education growing in developed countries today can be a framework for innovation mathematics in Indonesia in the 21st century. STEM education integrate understanding of science, math skills, and the available technology with the ability to perform engineering design process. Implementation of mathematics learning with STEM approach makes graduates trained in using of mathematics knowledge that they have to create innovative products that are able to solve the problems that exist in society.
Quantum heat engines and refrigerators: continuous devices.
Kosloff, Ronnie; Levy, Amikam
2014-01-01
Quantum thermodynamics supplies a consistent description of quantum heat engines and refrigerators up to a single few-level system coupled to the environment. Once the environment is split into three (a hot, cold, and work reservoir), a heat engine can operate. The device converts the positive gain into power, with the gain obtained from population inversion between the components of the device. Reversing the operation transforms the device into a quantum refrigerator. The quantum tricycle, a device connected by three external leads to three heat reservoirs, is used as a template for engines and refrigerators. The equation of motion for the heat currents and power can be derived from first principles. Only a global description of the coupling of the device to the reservoirs is consistent with the first and second laws of thermodynamics. Optimization of the devices leads to a balanced set of parameters in which the couplings to the three reservoirs are of the same order and the external driving field is in resonance. When analyzing refrigerators, one needs to devote special attention to a dynamical version of the third law of thermodynamics. Bounds on the rate of cooling when Tc→0 are obtained by optimizing the cooling current. All refrigerators as Tc→0 show universal behavior. The dynamical version of the third law imposes restrictions on the scaling as Tc→0 of the relaxation rate γc and heat capacity cV of the cold bath.
Ceramic Technology for Advanced Heat Engines Project
Energy Technology Data Exchange (ETDEWEB)
1990-08-01
The Ceramic Technology For Advanced Heat Engines Project was developed by the Department of Energy's Office of Transportation Systems (OTS) in Conservation and Renewable Energy. This project, part of the OTS's Advanced Materials Development Program, was developed to meet the ceramic technology requirements of the OTS's automotive technology programs. Significant accomplishments in fabricating ceramic components for the Department of Energy (DOE), National Aeronautics and Space Administration (NASA), and Department of Defense (DOD) advanced heat engine programs have provided evidence that the operation of ceramic parts in high-temperature engine environments is feasible. However, these programs have also demonstrated that additional research is needed in materials and processing development, design methodology, and data base and life prediction before industry will have a sufficient technology base from which to produce reliable cost-effective ceramic engine components commercially. An assessment of needs was completed, and a five year project plan was developed with extensive input from private industry. The objective of the project is to develop the industrial technology base required for reliable ceramics for application in advanced automotive heat engines. The project approach includes determining the mechanisms controlling reliability, improving processes for fabricating existing ceramics, developing new materials with increased reliability, and testing these materials in simulated engine environments to confirm reliability. Although this is a generic materials project, the focus is on structural ceramics for advanced gas turbine and diesel engines, ceramic hearings and attachments, and ceramic coatings for thermal barrier and wear applications in these engines.
Integrated Heat Exchange For Recuperation In Gas Turbine Engines
2016-12-01
combustion engines conduct heat transfer in the exhaust system. The exhaust valves have hollow stems containing sodium, which act as heat pipes with...is the use of heat pipes in internal combustion engines . Internal combustion engines have combustion chambers with temperatures as high as 2700 K...accomplished using evaporative heat pipes . This study explores the feasibility of embedding this heat exchange system within engines using a
Mathematical modeling in wound healing, bone regeneration and tissue engineering.
Geris, Liesbet; Gerisch, Alf; Schugart, Richard C
2010-12-01
The processes of wound healing and bone regeneration and problems in tissue engineering have been an active area for mathematical modeling in the last decade. Here we review a selection of recent models which aim at deriving strategies for improved healing. In wound healing, the models have particularly focused on the inflammatory response in order to improve the healing of chronic wound. For bone regeneration, the mathematical models have been applied to design optimal and new treatment strategies for normal and specific cases of impaired fracture healing. For the field of tissue engineering, we focus on mathematical models that analyze the interplay between cells and their biochemical cues within the scaffold to ensure optimal nutrient transport and maximal tissue production. Finally, we briefly comment on numerical issues arising from simulations of these mathematical models.
Single-particle stochastic heat engine
Rana, Shubhashis; Pal, P. S.; Saha, Arnab; Jayannavar, A. M.
2014-10-01
We have performed an extensive analysis of a single-particle stochastic heat engine constructed by manipulating a Brownian particle in a time-dependent harmonic potential. The cycle consists of two isothermal steps at different temperatures and two adiabatic steps similar to that of a Carnot engine. The engine shows qualitative differences in inertial and overdamped regimes. All the thermodynamic quantities, including efficiency, exhibit strong fluctuations in a time periodic steady state. The fluctuations of stochastic efficiency dominate over the mean values even in the quasistatic regime. Interestingly, our system acts as an engine provided the temperature difference between the two reservoirs is greater than a finite critical value which in turn depends on the cycle time and other system parameters. This is supported by our analytical results carried out in the quasistatic regime. Our system works more reliably as an engine for large cycle times. By studying various model systems, we observe that the operational characteristics are model dependent. Our results clearly rule out any universal relation between efficiency at maximum power and temperature of the baths. We have also verified fluctuation relations for heat engines in time periodic steady state.
A course of mathematics for engineerings and scientists
Chirgwin, Brian H
1984-01-01
A Course of Mathematics for Engineers and Scientists, Volume 2 continues the course of pure and applied mathematics for undergraduate science and engineering students. It contains further examples and exercises from examination papers from Oxford University, Cambridge University, and the University of London. The topics covered in this book include differential equations, linear equations, matrices and determinants, vector algebra and coordinate geometry, and differentiation and integration of functions of two or more variables. This book is intended as a reference for students taking science
The heat treatment of steel. A mathematical control problem
Energy Technology Data Exchange (ETDEWEB)
Hoemberg, Dietmar; Kern, Daniela
2009-07-21
The goal of this paper is to show how the heat treatment of steel can be modelled in terms of a mathematical optimal control problem. The approach is applied to laser surface hardening and the cooling of a steel slab including mechanical effects. Finally, it is shown how the results can be utilized in industrial practice by a coupling with machine-based control. (orig.)
Deep heat muscle treatment: A mathematical model - I
International Nuclear Information System (INIS)
Ogulu, A.; Bestman, A.R.
1992-03-01
The flow of blood during deep heat muscle treatment is studied in this paper. We model the blood vessel as a long tube in circular section whose radius varied slowly. Under the Boussinesq approximation, we seek asymptotic series expansions for the velocity components, temperature and pressure about a small parameter, ε, characterizing the radius variation. The study reveals mathematically why physicians recommend a hot bath for cuts and physiotherapists use ice packs for bruises. (author). 5 refs, 3 figs
Advanced Analysis of Isobaric Heat Capacities by Mathematical Gnostics
Czech Academy of Sciences Publication Activity Database
Wagner, Zdeněk; Bendová, Magdalena; Rotrekl, Jan; Velíšek, Petr; Storch, Jan; Uchytil, Petr; Setničková, Kateřina; Řezníčková Čermáková, Jiřina
2017-01-01
Roč. 46, 9-10 (2017), s. 1836-1853 ISSN 0095-9782. [International Symposium on Solubility Phenomena and Related Equilibrium Processes. Geneva, 24.07.2016-29.07.2016] R&D Projects: GA MŠk LD14090 Institutional support: RVO:67985858 Keywords : isobaric heat capacity * ionic liquids * mathematical gnostics Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 1.342, year: 2016
Heat transfer applications for the practicing engineer
Theodore, Louis
2011-01-01
This book serves as a training tool for individuals in industry and academia involved with heat transfer applications. Although the literature is inundated with texts emphasizing theory and theoretical derivations, the goal of this book is to present the subject of heat transfer from a strictly pragmatic point of view. The book is divided into four Parts: Introduction, Principles, Equipment Design Procedures and Applications, and ABET-related Topics. The first Part provides a series of chapters concerned with introductory topics that are required when solving most engineering problems, inclu
Advanced mathematics for engineers and scientists
DuChateau, Paul
2012-01-01
This book can be used as either a primary text or a supplemental reference for courses in applied mathematics. Its core chapters are devoted to linear algebra, calculus, and ordinary differential equations. Additional topics include partial differential equations and approximation methods. Each chapter features an ample selection of solved problems. These problems were chosen to illustrate not only how to solve various algebraic and differential equations but also how to interpret the solutions in order to gain insight into the behavior of the system modeled by the equation. In addition to th
Quantum dynamical framework for Brownian heat engines
Agarwal, G. S.; Chaturvedi, S.
2013-07-01
We present a self-contained formalism modeled after the Brownian motion of a quantum harmonic oscillator for describing the performance of microscopic Brownian heat engines such as Carnot, Stirling, and Otto engines. Our theory, besides reproducing the standard thermodynamics results in the steady state, enables us to study the role dissipation plays in determining the efficiency of Brownian heat engines under actual laboratory conditions. In particular, we analyze in detail the dynamics associated with decoupling a system in equilibrium with one bath and recoupling it to another bath and obtain exact analytical results, which are shown to have significant ramifications on the efficiencies of engines involving such a step. We also develop a simple yet powerful technique for computing corrections to the steady state results arising from finite operation time and use it to arrive at the thermodynamic complementarity relations for various operating conditions and also to compute the efficiencies of the three engines cited above at maximum power. Some of the methods and exactly solvable models presented here are interesting in their own right and could find useful applications in other contexts as well.
Mathematical Model of the Jet Engine Fuel System
Directory of Open Access Journals (Sweden)
Klimko Marek
2015-01-01
Full Text Available The paper discusses the design of a simplified mathematical model of the jet (turbo-compressor engine fuel system. The solution will be based on the regulation law, where the control parameter is a fuel mass flow rate and the regulated parameter is the rotational speed. A differential equation of the jet engine and also differential equations of other fuel system components (fuel pump, throttle valve, pressure regulator will be described, with respect to advanced predetermined simplifications.
Mathematical Model of the Jet Engine Fuel System
Klimko, Marek
2015-05-01
The paper discusses the design of a simplified mathematical model of the jet (turbo-compressor) engine fuel system. The solution will be based on the regulation law, where the control parameter is a fuel mass flow rate and the regulated parameter is the rotational speed. A differential equation of the jet engine and also differential equations of other fuel system components (fuel pump, throttle valve, pressure regulator) will be described, with respect to advanced predetermined simplifications.
Experimental Study of the Gas Engine Driven Heat Pump with Engine Heat Recovery
Directory of Open Access Journals (Sweden)
Wei Zhang
2015-01-01
Full Text Available Gas engine driven heat pumps (GEHPs represent one of practical solutions to effectively utilize fossil fuel energy and reduce environmental pollution. In this paper, the performance characteristics of the GEHP were investigated experimentally with engine heat recovery. A GEHP test facility was set up for this purpose. The effects of several important factors including engine speed, ambient temperature, condenser water flow rate, and condenser water inlet temperature on the system performance were studied over a wide range of operating conditions. The results showed that the engine waste heat accounted for about 40–50% of the total heat capacity over the studied operating conditions. It also showed that engine speed and ambient temperature had significant effects on the GEHP performance. The coefficient of performance (COP and the primary energy ratio (PER decreased by 14% and 12%, respectively, as engine speed increased from 1400 rpm to 2000 rpm. On the other hand, the COP and PER of the system increased by 22% and 16%, respectively, with the ambient temperature increasing from 3 to 12°C. Furthermore, it was demonstrated that the condenser water flow rate and condenser water inlet temperature had little influence on the COP of the heat pump and the PER of the GEHP system.
Partial differential equations mathematical techniques for engineers
Epstein, Marcelo
2017-01-01
This monograph presents a graduate-level treatment of partial differential equations (PDEs) for engineers. The book begins with a review of the geometrical interpretation of systems of ODEs, the appearance of PDEs in engineering is motivated by the general form of balance laws in continuum physics. Four chapters are devoted to a detailed treatment of the single first-order PDE, including shock waves and genuinely non-linear models, with applications to traffic design and gas dynamics. The rest of the book deals with second-order equations. In the treatment of hyperbolic equations, geometric arguments are used whenever possible and the analogy with discrete vibrating systems is emphasized. The diffusion and potential equations afford the opportunity of dealing with questions of uniqueness and continuous dependence on the data, the Fourier integral, generalized functions (distributions), Duhamel's principle, Green's functions and Dirichlet and Neumann problems. The target audience primarily comprises graduate s...
Mathematical modeling of the energy consumption of heated swimming pools
Energy Technology Data Exchange (ETDEWEB)
Le Bel, C.; Millette, J. [LTE Shawinigan, Shawinigan, PQ (Canada)
2007-07-01
A mathematical model was developed to estimate the water temperature of a residential swimming pool. The model can compare 2 different situations and, if local climatic conditions are known, it can accurately predict energy costs of the pool relative to the total energy consumption of the house. When used with the appropriate energy transfer coefficient and weather file, the model can estimate the water temperature of a residential swimming pool having specific characteristics, such as in-ground, above-ground, heated or non-heated. The model is suitable for determining residential loads. It can be applied to different pool types and sizes, for different water heating scenarios and different climatic regions. Data obtained from the monitoring of water temperature and electricity use of 57 residential swimming pools was used to validate the model. In addition, 5 above-ground pools were installed on the property of LTE Shawinigan to allow for a more detailed study of the parameters involved in the thermal balance of a pool. The mathematical model, based on a global heat transfer coefficient, can determine the effect of a solar blanket and the effect of water volume. 14 refs., 5 tabs., 11 figs.
Ceramic technology for Advanced Heat Engines Project
Energy Technology Data Exchange (ETDEWEB)
Johnson, D.R.
1991-07-01
Significant accomplishments in fabricating ceramic components for advanced heat engine programs have provided evidence that the operation of ceramic parts in high-temperature engine environments is feasible. However, these programs have also demonstrated that additional research is needed in materials and processing development, design methodology, and database and life prediction before industry will have a sufficient technology base from which to produce reliable cost-effective ceramic engine components commercially. An assessment of needs was completed, and a five year project plan was developed with extensive input from private industry. The project approach includes determining the mechanisms controlling reliability, improving processes for fabricating existing ceramics, developing new materials with increased reliability, and testing these materials in simulated engine environments to confirm reliability. Although this is a generic materials project, the focus is on the structural ceramics for advanced gas turbine and diesel engines, ceramic bearings and attachments, and ceramic coatings for thermal barrier and wear applications in these engines. To facilitate the rapid transfer of this technology to US industry, the major portion of the work is being done in the ceramic industry, with technological support from government laboratories, other industrial laboratories, and universities. This project is managed by ORNL for the Office of Transportation Technologies, Office of Transportation Materials, and is closely coordinated with complementary ceramics tasks funded by other DOE offices, NASA, DOD, and industry.
Taiwanese Preservice Teachers' Science, Technology, Engineering, and Mathematics Teaching Intention
Lin, Kuen-Yi; Williams, P. John
2016-01-01
This study applies the theory of planned behavior as a basis for exploring the impact of knowledge, values, subjective norms, perceived behavioral controls, and attitudes on the behavioral intention toward science, technology, engineering, and mathematics (STEM) education among Taiwanese preservice science teachers. Questionnaires (N = 139)…
Control Engineering, System Theory and Mathematics: The Teacher's Challenge
Zenger, K.
2007-01-01
The principles, difficulties and challenges in control education are discussed and compared to the similar problems in the teaching of mathematics and systems science in general. The difficulties of today's students to appreciate the classical teaching of engineering disciplines, which are based on rigorous and scientifically sound grounds, are…
Use of Mathematical Methods of Statistics for Analyzing Engine Characteristics
Directory of Open Access Journals (Sweden)
Aivaras Jasilionis
2012-11-01
Full Text Available For the development of new models, automobile manufacturers are trying to come up with optimal software for engine control in all movement modes. However, in this case, a vehicle cannot reach outstanding characteristics in none of them. This is the main reason why modifications in engine control software used for adapting the vehicle for driver’s needs are becoming more and more popular. The article presents a short analysis of development trends towards engine control software. Also, models of mathematical statistics for engine power and torque growth are created. The introduced models give an opportunity to predict the probabilities of engine power or torque growth after individual reprogramming of engine control software.
Applied Mathematics for agronomical engineers in Spain at UPM
Anton, J. M.; Grau, J. B.; Tarquis, A. M.; Fabregat, J.; Sanchez, M. E.
2009-04-01
Mathematics, created or discovered, are a global human conceptual endowment, containing large systems of knowledge, and varied skills to use definite parts of them, in creation or discovery, or for applications, e.g. in Physics, or notably in engineering behaviour. When getting upper intellectual levels in the 19th century, the agronomical science and praxis was noticeably or mainly organised in Spain in agronomical engineering schools and also in institutes, together with technician schools, also with different lower lever centres, and they have evolved with progress and they are much changing at present to a EEES schema (Bolonia process). They work in different lines that need some basis or skills from mathematics. The vocation to start such careers, that have varied curriculums, contains only some mathematics, and the number of credits for mathematics is restrained because time is necessary for other initial sciences such as applied chemistry, biology, ecology and soil sciences, but some basis and skill of maths are needed, also with Physics, at least for electricity, machines, construction, economics at initial ground levels, and also for Statistics that are here considered part of Applied Mathematics. The ways of teaching mathematical basis and skills are especial, and are different from the practical ways needed e. g. for Soil Sciences, and they involve especial efforts from students, and especial controls or exams that guide much learning. The mathematics have a very large accepted content that uses mostly a standard logic, and that is remarkably stable and international, rather similar notation and expressions being used with different main languages. For engineering the logical basis is really often not taught, but the use of it is transferred, especially for calculus that requires both adapted somehow simplified schemas and the learning of a specific skill to use it, and also for linear algebra. The basic forms of differential calculus in several
A Mathematical Model of Marine Diesel Engine Speed Control System
Sinha, Rajendra Prasad; Balaji, Rajoo
2018-02-01
Diesel engine is inherently an unstable machine and requires a reliable control system to regulate its speed for safe and efficient operation. Also, the diesel engine may operate at fixed or variable speeds depending upon user's needs and accordingly the speed control system should have essential features to fulfil these requirements. This paper proposes a mathematical model of a marine diesel engine speed control system with droop governing function. The mathematical model includes static and dynamic characteristics of the control loop components. Model of static characteristic of the rotating fly weights speed sensing element provides an insight into the speed droop features of the speed controller. Because of big size and large time delay, the turbo charged diesel engine is represented as a first order system or sometimes even simplified to a pure integrator with constant gain which is considered acceptable in control literature. The proposed model is mathematically less complex and quick to use for preliminary analysis of the diesel engine speed controller performance.
Determination and Application of Comprehensive Specific Frictional Resistance in Heating Engineering
Directory of Open Access Journals (Sweden)
Yanan Tian
2018-01-01
Full Text Available In this study, we analyze the deficiencies of specific frictional resistance in heating engineering. Based on economic specific frictional resistance, we put forward the concept of comprehensive specific frictional resistance, which considers the multiple factors of technology, economy, regulation modes, pipe segment differences, and medium pressure. Then, we establish a mathematical model of a heating network across its lifespan in order to develop a method for determining the comprehensive specific frictional resistance. Relevant conclusions can be drawn from the results. As an application, we have planned the heating engineering for Yangyuan County in China, which demonstrates the feasibility and superiority of the method.
Mathematical methods in engineering and physics
Felder, Gary N
2016-01-01
This text is intended for the undergraduate course in math methods, with an audience of physics and engineering majors. As a required course in most departments, the text relies heavily on explained examples, real-world applications and student engagement. Supporting the use of active learning, a strong focus is placed upon physical motivation combined with a versatile coverage of topics that can be used as a reference after students complete the course. Each chapter begins with an overview that includes a list of prerequisite knowledge, a list of skills that will be covered in the chapter, and an outline of the sections. Next comes the motivating exercise, which steps the students through a real-world physical problem that requires the techniques taught in each chapter.
Rančić, Milica
2016-01-01
This book highlights the latest advances in engineering mathematics with a main focus on the mathematical models, structures, concepts, problems and computational methods and algorithms most relevant for applications in modern technologies and engineering. In particular, it features mathematical methods and models of applied analysis, probability theory, differential equations, tensor analysis and computational modelling used in applications to important problems concerning electromagnetics, antenna technologies, fluid dynamics, material and continuum physics and financial engineering. The individual chapters cover both theory and applications, and include a wealth of figures, schemes, algorithms, tables and results of data analysis and simulation. Presenting new methods and results, reviews of cutting-edge research, and open problems for future research, they equip readers to develop new mathematical methods and concepts of their own, and to further compare and analyse the methods and results discussed. The ...
Course of mathematics for engineers and scientists v.1
Chirgwin, Brian H
1961-01-01
A Course of Mathematics for Engineers and Scientists, Volume 1 studies the various concepts in pure and applied mathematics, specifically the technique and applications of differentiation and integration of one variable, geometry of two dimensions, and complex numbers. The book is divided into seven chapters, wherein the first of which presents the introductory concepts, such as the functional notation and fundamental definitions; the roots of equations; and limits and continuity. The text then tackles the techniques and applications of differentiation and integration. Geometry of two dimensio
Course of mathematics for engineerings and scientists v.5
Chirgwin, Brian H
2013-01-01
A Course of Mathematics for Engineers and Scientists, Volume 5 presents the solutions of differential equations by obtaining the results in different forms. This book discusses the significant branch of mathematics generalizing the elementary ideas of function, integration, and differentiation. Organized into four chapters, this volume begins with an overview of the use of Fourier series that leads to solutions consisting of infinite series. This text then discusses the fundamental advantage of Laplace and Fourier transformation. Other chapters consider the technique of obtaining the solutions
Mathematical methods for mathematicians, physical scientists and engineers
Dunning-Davies, J
2003-01-01
This practical introduction encapsulates the entire content of teaching material for UK honours degree courses in mathematics, physics, chemistry and engineering, and is also appropriate for post-graduate study. It imparts the necessary mathematics for use of the techniques, with subject-related worked examples throughout. The text is supported by challenging problem exercises (and answers) to test student comprehension. Index notation used in the text simplifies manipulations in the sections on vectors and tensors. Partial differential equations are discussed, and special functions introduced
Superconductor Particles As The Working Media Of A Heat Engine
Keefe, Peter D.
2011-12-01
A heat engine is presented in which the working media comprises a multiplicity of mutually isolated particles of Type I superconductor which are selectively processed through H-T phase space so as to convert a heat influx from a high temperature heat reservoir into a useful work output, wherein no heat is rejected to a low temperature heat reservoir.
Sorption heat engines: simple inanimate negative entropy generators
Muller, Anthonie W. J.; Schulze-Makuch, Dirk
2005-01-01
The name 'sorption heat engines' is proposed for simple negative entropy generators that are driven by thermal cycling and work on alternating adsorption and desorption. These generators are in general not explicitly recognized as heat engines. Their mechanism is applicable to the fields of engineering, physics, chemistry, geology, and biology, in particular the origin of life. Four kinds of sorption heat engines are distinguished depending on the occurrence of changes in the adsorbent or ads...
Quantum heat engine with coupled superconducting resonators
DEFF Research Database (Denmark)
Hardal, Ali Ümit Cemal; Aslan, Nur; Wilson, C. M.
2017-01-01
the differences between the quantum and classical descriptions of our system by solving the quantum master equation and classical Langevin equations. Specifically, we calculate the mean number of excitations, second-order coherence, as well as the entropy, temperature, power, and mean energy to reveal......We propose a quantum heat engine composed of two superconducting transmission line resonators interacting with each other via an optomechanical-like coupling. One resonator is periodically excited by a thermal pump. The incoherently driven resonator induces coherent oscillations in the other one...... the signatures of quantum behavior in the statistical and thermodynamic properties of the system. We find evidence of a quantum enhancement in the power output of the engine at low temperatures....
Quantum optomechanical piston engines powered by heat
Mari, A.; Farace, A.; Giovannetti, V.
2015-09-01
We study two different models of optomechanical systems where a temperature gradient between two radiation baths is exploited for inducing self-sustained coherent oscillations of a mechanical resonator. From a thermodynamic perspective, such systems represent quantum instances of self-contained thermal machines converting heat into a periodic mechanical motion and thus they can be interpreted as nano-scale analogues of macroscopic piston engines. Our models are potentially suitable for testing fundamental aspects of quantum thermodynamics in the laboratory and for applications in energy efficient nanotechnology.
Quantum optomechanical piston engines powered by heat
International Nuclear Information System (INIS)
Mari, A; Farace, A; Giovannetti, V
2015-01-01
We study two different models of optomechanical systems where a temperature gradient between two radiation baths is exploited for inducing self-sustained coherent oscillations of a mechanical resonator. From a thermodynamic perspective, such systems represent quantum instances of self-contained thermal machines converting heat into a periodic mechanical motion and thus they can be interpreted as nano-scale analogues of macroscopic piston engines. Our models are potentially suitable for testing fundamental aspects of quantum thermodynamics in the laboratory and for applications in energy efficient nanotechnology. (paper)
Optimization of solar-powered Stirling heat engine with finite-time thermodynamics
Energy Technology Data Exchange (ETDEWEB)
Yaqi, Li [School of Energy and Power Engineering, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Xi' an Research Institute of Hi-Tech, Xi' an, Shaanxi 710025 (China); Yaling, He; Weiwei, Wang [School of Energy and Power Engineering, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China)
2011-01-15
A mathematical model for the overall thermal efficiency of the solar-powered high temperature differential dish-Stirling engine with finite-rate heat transfer, regenerative heat losses, conductive thermal bridging losses and finite regeneration processes time is developed. The model takes into consideration the effect of the absorber temperature and the concentrating ratio on the thermal efficiency; radiation and convection heat transfer between the absorber and the working fluid as well as convection heat transfer between the heat sink and the working fluid. The results show that the optimized absorber temperature and concentrating ratio are at about 1100 K and 1300, respectively. The thermal efficiency at optimized condition is about 34%, which is not far away from the corresponding Carnot efficiency at about 50%. Hence, the present analysis provides a new theoretical guidance for designing dish collectors and operating the Stirling heat engine system. (author)
The Mathematical Modelling of Heat Transfer in Electrical Cables
Directory of Open Access Journals (Sweden)
Bugajev Andrej
2014-05-01
Full Text Available This paper describes a mathematical modelling approach for heat transfer calculations in underground high voltage and middle voltage electrical power cables. First of the all typical layout of the cable in the sand or soil is described. Then numerical algorithms are targeted to the two-dimensional mathematical models of transient heat transfer. Finite Volume Method is suggested for calculations. Different strategies of nonorthogonality error elimination are considered. Acute triangles meshes were applied in two-dimensional domain to eliminate this error. Adaptive mesh is also tried. For calculations OpenFOAM open source software which uses Finite Volume Method is applied. To generate acute triangles meshes aCute library is used. The efficiency of the proposed approach is analyzed. The results show that the second order of convergence or close to that is achieved (in terms of sizes of finite volumes. Also it is shown that standard strategy, used by OpenFOAM is less efficient than the proposed approach. Finally it is concluded that for solving real problem a spatial adaptive mesh is essential and adaptive time steps also may be needed.
Darlington, Ellie; Bowyer, Jessica
2017-01-01
An ongoing reform programme of the post-16 Advanced "A"-level qualifications in England and Wales means that pre-university mathematics content and assessment will change from 2017. Undergraduate engineering is a subject that relies heavily on mathematics, and applicants to engineering degree programmes in the UK are required to have…
DEFF Research Database (Denmark)
Triantafyllou, Evangelia; Misfeldt, Morten; Timcenko, Olga
2016-01-01
This article explores student attitudes and preferences in learning and teaching of mathematics in engineering studies that transcend the division between technical, scientific and artistic disciplines. For observing such attitudes, we have developed a model that relates the attitude towards...... by a teacher. We propose that these findings inspire reforming mathematical education for such engineering students....
Effect of finite heat input on the power performance of micro heat engines
International Nuclear Information System (INIS)
Khu, Kerwin; Jiang, Liudi; Markvart, Tom
2011-01-01
Micro heat engines have attracted considerable interest in recent years for their potential exploitation as micro power sources in microsystems and portable devices. Thermodynamic modeling can predict the theoretical performance that can be potentially achieved by micro heat engine designs. An appropriate model can not only provide key information at the design stage but also indicate the potential room for improvement in existing micro heat engines. However, there are few models reported to date which are suitable for evaluating the power performance of micro heat engines. This paper presents a new thermodynamic model for determining the theoretical limit of power performance of micro heat engines with consideration to finite heat input and heat leakage. By matching the model components to those of a representative heat engine layout, the theoretical power, power density, and thermal efficiency achievable for a micro heat engine can be obtained for a given set of design parameters. The effects of key design parameters such as length and thermal conductivity of the engine material on these theoretical outputs are also investigated. Possible trade-offs among these performance objectives are discussed. Performance results derived from the developed model are compared with those of a working micro heat engine (P3) as an example. -- Highlights: → Thermodynamic model for micro heat engines. → Effect of different parameters on potential performance. → Tradeoffs for determining optimal size of micro engines.
MATHEMATICAL MODELLING OF OPERATION HEAT NETWORKS IN VIEW OF HEAT LOSS
Directory of Open Access Journals (Sweden)
ZBARAZ L. I.
2016-08-01
Full Text Available Goal. In recent years, due to a significant rise in price of energy, the reduction of direct costs for heating becomes a priority. In the utilities especially important to optimization of energy heating system equipment. During transport of thermal energy in the distribution networks thermal losses occur along the length of the hydraulic pipes and the coolant pumping losses. These loss-dependence of the particular distribution network. Changing temperature and the hydraulic regime at the source necessary to achieve the minimum cost of transport for today acting tariffs for energy. Scientific novelty. The studies received law changes head to the source at the qualitative and quantitative methods of regulation. Results. A mathematical model of an extensive network of decentralized heat source heating, which are analyzed using different methods of regulating and found the best.
A Mathematical Model of Heat Transfer in Spheroplastic
Directory of Open Access Journals (Sweden)
V. S. Zarubin
2016-01-01
Full Text Available Spheroplastics are composite materials composed of a polymer or organosilicate binder and hollow spherical inclusions (mostly, of glass, but there are also of carbon, phenol, and epoxy, which are called microspheres and have a diameter within a millimeter with the wall thickness of several micrometers. To reduce the material density in watercraft constructions sometimes are used so called macrospheres of up to 40 mm in diameter and shell thickness of 0,5--1,5 mm from spheroplastic with microspheres.Microspheres may contain inert gases such as nitrogen. Many countries have commercialised quartz microspheres. The USA, in particular, produces Q-Gel microspheres with density of 300 kg / m3, the bulk density - 100 kg / m3 and the average diameter of 75 microns,characterized by a high mechanical strength and low cost. Carbon microspheres having low mechanical properties can absorb radio waves in certain frequency ranges. Spheroplastic with silicone microspheres combine relatively high mechanical and dielectric properties.In virtue of low thermal conductivity spheroplastics are used in various heat-insulating structures. As the thermal insulation coatings, the spheroplastic covers the outer surface of the pipes, in particular oil and gas pipelines in the permafrost zones, regions of swampy ground, and underwater. The effective heat conductivity factor, primarily, determines the specific application of spheroplastic as a thermal insulation material. To quantify the value of this factor is necessary to have a mathematical model describing heat ransfer in spheroplastic.The paper presents a four-phase mathematical model of the heat transfer in a representative element of a spheroplastic structure placed in an unlimited array of homogeneous material, the thermal conductivity of which is to be determined as desired characteristics of spheroplastic. This model in combination with a dual variational formulation of stationary heat conduction problem in the
Holographic heat engine within the framework of massive gravity
Mo, Jie-Xiong; Li, Gu-Qiang
2018-05-01
Heat engine models are constructed within the framework of massive gravity in this paper. For the four-dimensional charged black holes in massive gravity, it is shown that the existence of graviton mass improves the heat engine efficiency significantly. The situation is more complicated for the five-dimensional neutral black holes since the constant which corresponds to the third massive potential also contributes to the efficiency. It is also shown that the existence of graviton mass can improve the heat engine efficiency. Moreover, we probe how the massive gravity influences the behavior of the heat engine efficiency approaching the Carnot efficiency.
Ceramic technology for advanced heat engines project
Energy Technology Data Exchange (ETDEWEB)
1990-09-01
The Ceramic Technology for Advanced Heat Engines Project was developed by the Department of Energy's Office of Transportation Systems in Conservation and Renewable Energy. This project was developed to meet the ceramic technology requirements of the OTT's automotive technology programs. This project is managed by ORNL and is closely coordinated with complementary ceramics tasks funded by other DOE offices, NASA, DoD, and industry. Research is discussed under the following topics; Turbomilling of SiC Whiskers; microwave sintering of silicon nitride; and milling characterization; processing of monolithics; silicon nitride matrix; oxide matrix; silicate matrix; thermal and wear coatings; joining; design; contact interfaces; time-dependent behavior; environmental effects; fracture mechanics; nondestructive evaluation; and technology transfer. References, figures, and tables are included with each topic.
Understanding Immunology via Engineering Design: The Role of Mathematical Prototyping
Klinke, David J.; Wang, Qing
2012-01-01
A major challenge in immunology is how to translate data into knowledge given the inherent complexity and dynamics of human physiology. Both the physiology and engineering communities have rich histories in applying computational approaches to translate data obtained from complex systems into knowledge of system behavior. However, there are some differences in how disciplines approach problems. By referring to mathematical models as mathematical prototypes, we aim to highlight aspects related to the process (i.e., prototyping) rather than the product (i.e., the model). The objective of this paper is to review how two related engineering concepts, specifically prototyping and “fitness for use,” can be applied to overcome the pressing challenge in translating data into improved knowledge of basic immunology that can be used to improve therapies for disease. These concepts are illustrated using two immunology-related examples. The prototypes presented focus on the beta cell mass at the onset of type 1 diabetes and the dynamics of dendritic cells in the lung. This paper is intended to illustrate some of the nuances associated with applying mathematical modeling to improve understanding of the dynamics of disease progression in humans. PMID:22973412
Quantum heat engine with coupled superconducting resonators
Hardal, Ali Ü. C.; Aslan, Nur; Wilson, C. M.; Müstecaplıoǧlu, Özgür E.
2017-12-01
We propose a quantum heat engine composed of two superconducting transmission line resonators interacting with each other via an optomechanical-like coupling. One resonator is periodically excited by a thermal pump. The incoherently driven resonator induces coherent oscillations in the other one due to the coupling. A limit cycle, indicating finite power output, emerges in the thermodynamical phase space. The system implements an all-electrical analog of a photonic piston. Instead of mechanical motion, the power output is obtained as a coherent electrical charging in our case. We explore the differences between the quantum and classical descriptions of our system by solving the quantum master equation and classical Langevin equations. Specifically, we calculate the mean number of excitations, second-order coherence, as well as the entropy, temperature, power, and mean energy to reveal the signatures of quantum behavior in the statistical and thermodynamic properties of the system. We find evidence of a quantum enhancement in the power output of the engine at low temperatures.
Black holes in massive gravity as heat engines
Hendi, S. H.; Eslam Panah, B.; Panahiyan, S.; Liu, H.; Meng, X.-H.
2018-06-01
The paper at hand studies the heat engine provided by black holes in the presence of massive gravity. The main motivation is to investigate the effects of massive gravity on different properties of the heat engine. It will be shown that massive gravity parameters modify the efficiency of engine on a significant level. Furthermore, it will be pointed out that it is possible to have a heat engine for non-spherical black holes in massive gravity, and therefore, we will study the effects of horizon topology on the properties of heat engine. Surprisingly, it will be shown that the highest efficiency for the heat engine belongs to black holes with the hyperbolic horizon, while the lowest one belongs to the spherical black holes.
Heat engine development for solar thermal power systems
Pham, H. Q.; Jaffe, L. D.
The parabolic dish solar collector systems for converting sunlight to electrical power through a heat engine will, require a small heat engine of high performance long lifetime to be competitive with conventional power systems. The most promising engine candidates are Stirling, high temperature Brayton, and combined cycle. Engines available in the current market today do not meet these requirements. The development of Stirling and high temperature Brayton for automotive applications was studied which utilizes much of the technology developed in this automotive program for solar power engines. The technical status of the engine candidates is reviewed and the components that may additional development to meet solar thermal system requirements are identified.
Mathematical Modeling and Simulation Introduction for Scientists and Engineers
Velten, Kai
2008-01-01
This concise and clear introduction to the topic requires only basic knowledge of calculus and linear algebra—all other concepts and ideas are developed in the course of the book. Lucidly written so as to appeal to undergraduates and practitioners alike, it enables readers to set up simple mathematical models on their own and to interpret their results and those of others critically. To achieve this, many examples have been chosen from various fields, such as biology, ecology, economics, medicine, agricultural, chemical, electrical, mechanical and process engineering, which are subsequently di
2013-04-03
... procedure acceptable to the NRC staff for providing summary details of mathematical modeling methods used in... NUCLEAR REGULATORY COMMISSION [NRC-2013-0062] Reporting Procedure for Mathematical Models Selected... Regulatory Guide (RG) 4.4, ``Reporting Procedure for Mathematical Models Selected to Predict Heated Effluent...
A Mathematical Model for the Exhaust Gas Temperature Profile of a Diesel Engine
Brito, C. H. G.; Maia, C. B.; Sodré, J. R.
2015-09-01
This work presents a heat transfer model for the exhaust gas of a diesel power generator to determine the gas temperature profile in the exhaust pipe. The numerical methodology to solve the mathematical model was developed using a finite difference method approach for energy equation resolution and determination of temperature profiles considering turbulent fluid flow and variable fluid properties. The simulation was carried out for engine operation under loads from 0 kW to 40 kW. The model was compared with results obtained using the multidimensional Ansys CFX software, which was applied to solve the governor equations of turbulent fluid flow. The results for the temperature profiles in the exhaust pipe show a good proximity between the mathematical model developed and the multidimensional software.
A Study of Competence in Mathematics and Mechanics in an Engineering Curriculum
Munns, Andrew
2017-01-01
Professional bodies expect engineers to show competence in both mathematics and engineering topics such as mechanics, using their abilities in both of these to solve problems. Yet within engineering programmes there is a phenomenon known as "The Mathematics Problem", with students not demonstrating understanding of the subject. This…
A National Study of Mathematics Requirements for Scientists and Engineers. Final Report.
Miller, G. H.
The National Study of Mathematics Requirements for Scientists and Engineers is concerned with establishing the mathematics experiences desired for the many specializations in science and engineering, such as microbiology, organic chemistry, electrical engineering, and molecular physics. An instruction and course content sheet and a course…
Thermodynamic analysis of a new Marnoch Heat Engine
International Nuclear Information System (INIS)
Saneipoor, P.; Dincer, I.; Naterer, G.F.
2013-01-01
In this paper, recovery of waste heat from an industrial facility with a new Marnoch Heat Engine (MHE) is examined. The MHE can be operated with temperature differentials below 100 K. A flowing liquid transfers heat from the heat source into heat exchangers and then removes heat from cold heat exchangers. Compressed dry air is used as a working medium in the heat engine. In this paper, the mechanical configuration of the heat engine is presented and analyzed. A thermodynamic model is developed to study the performance of the heat engine under various operating conditions. The results show that the exergy efficiency of the MHE reaches up to 17%. The major sources of exergy loss are presented and discussed, in order to optimize the system performance. -- Highlights: ► To develop a thermodynamic model to study the performance of a Marnoch Heat Engine (MHE). ► To investigate the effects of changing operational conditions on the MHE's efficiency. ► To assess the application of the MHE's commercial viability
Turbofan engine mathematic model for its static and dynamic characteristics research
Directory of Open Access Journals (Sweden)
О.Є. Карпов
2004-01-01
Full Text Available Demands to mathematical model of the turbofan engine are determined in the article. The mathematical model is used for calculations static and dynamic parameters, which are required for estimation of engine technical state in operation. There are the mathematical model of the turbofan engine AИ-25 and the results of calculations static and dynamic parameters at initial condition in the article.
Modelling of the heat load in the piston of turbo diesel engine - continuation
Directory of Open Access Journals (Sweden)
Piotr GUSTOF
2007-01-01
Full Text Available In this study the mathematical description of characteristic surfaces of the heat exchange of the piston and temperature distribution of the turbo diesel engine at the beginning phase its work was presented. The computations were performed by means of the two-zone combustion model, the boundary conditions of III kind and the finite elements method (MES by using of COSMOS/M program.
2010-01-01
The mathematical model of heat transfer in whole-body hyperthermia, developed earlier by the author, has been refined using the mathematical apparatus of the circuit theory. The model can be used to calculate the temperature of each organ, which can increase the efficacy and safety of the immersion-convection technique of whole-body hyperthermia.
A quantum heat engine based on Tavis-Cummings model
Sun, Kai-Wei; Li, Ran; Zhang, Guo-Feng
2017-09-01
This paper will investigate a four-stroke quantum heat engine based on the Tavis-Cummings model. The cycle of the heat engine is similar to the Otto cycle in classical thermodynamics. The relationship between output power as well as cycle efficiency and external physical system parameters are given. Under this condition, the entanglement behavior of the system will be studied. The system can show considerable entanglement by strictly controlling relevant parameters. Unlike common two-level quantum heat engines, efficiency is a function of temperature, showing interesting and unexpected phenomena. Several ways to adjust engine properties by external parameters are proposed, with which the output power and efficiency can be optimized. The heat engine model exhibits high efficiency and output power with the participation of a small number of photons, and decay rapidly as the number of photons increases in entangled area but shows interesting behaviors in non-entangled area of photon numbers.
On the question of heat engine cycles optimization
Directory of Open Access Journals (Sweden)
Костянтин Ігорович Ткаченко
2015-10-01
Full Text Available It is known that the efficiency of heat engines nowadays isn’t more than 50-60% for prototypes and maximum possible efficiency of a heat engine is considered Carnot cycle efficiency Thus, at least 40% of the disposable amount of heat is lost in the surrounding medium, unless the waste gases heat is utilized somehow. General idea of heat engines cycles is the transfer of energy from the heater (both external and internal to a working fluid, obtaining mechanical work from expanding of the working fluid, and returning the working fluid to the initial state by compression and excess heat discharge into a cooler. In this paper the combination of a heat engine operating according to the standard Edwards cycle and consisting of isochor, adiabat and isotherm, and the heat pump, using the reverse Carnot cycle is investigated. The heat pump partially picks out the heat of the working fluid at its isothermal compression, and returns it to the equivalent working fluid or regenerator cap, at the beginning of isochoric heating. The efficiency coefficient of the heat pump, and thus the work to putting it into action is calculated by proper equations at the constant temperature of the low-potential heat source (working fluid and variable temperature of the heated equivalent of the working fluid or the regenerator cap. Taking as an example selected quantitative parameters of the Edwards cycle it has been proved that the use of the heat pump increases the effective efficiency of combined cycle as compared to the basic one. In addition, it has been shown that the dependence of the efficiency on the degree of heat return is not monotonic and has a maximum
Heat pipes to reduce engine exhaust emissions
Schultz, D. F. (Inventor)
1984-01-01
A fuel combustor is presented that consists of an elongated casing with an air inlet conduit portion at one end, and having an opposite exit end. An elongated heat pipe is mounted longitudinally in the casing and is offset from and extends alongside the combustion space. The heat pipe is in heat transmitting relationship with the air intake conduit for heating incoming air. A guide conduit structure is provided for conveying the heated air from the intake conduit into the combustion space. A fuel discharge nozzle is provided to inject fuel into the combustion space. A fuel conduit from a fuel supply source has a portion engaged in heat transfer relationship of the heat pipe for preheating the fuel. The downstream end of the heat pipe is in heat transfer relationship with the casing and is located adjacent to the downstream end of the combustion space. The offset position of the heat pipe relative to the combustion space minimizes the quenching effect of the heat pipe on the gaseous products of combustion, as well as reducing coking of the fuel on the heat pipe, thereby improving the efficiency of the combustor.
Directory of Open Access Journals (Sweden)
Alexandros Sotirios Anifantis
2018-02-01
Full Text Available Nowadays, the traditional energy sources used for greenhouse heating are fossil fuels such as LPG, diesel and natural gas. The global energy demand will continue to grow and alternative technologies need to be developed in order to improve the sustainability of crop production in protected environments. Innovative solutions are represented by renewable energy plants such as photovoltaic, wind and geothermal integrated systems, however, these technologies need to be connected to the power grid in order to store the energy produced. On agricultural land, power grids are not widespread and stand-alone renewable energy systems should be investigated especially for greenhouse applications. The aim of this research is to analyze, by means of a mathematical model, the energy efficiency of a photovoltaic (8.2 kW, hydrogen (2.5 kW and ground source gas heat pump (2.2 kW integrated in a stand-alone system used for heating an experimental greenhouse tunnel (48 m2 during the winter season. A yearlong energy performance analysis was conducted for three different types of greenhouse cover materials, a single layer polyethylene film, an air inflated-double layer polyethylene film, and a double acrylic or polycarbonate. The results of one year showed that the integrated system had a total energy efficiency of 14.6%. Starting from the electric energy supplied by the photovoltaic array, the total efficiency of the hydrogen and ground source gas heat pump system was 112% if the coefficient of the performance of the heat pump is equal to 5. The heating system increased the greenhouse air temperatures by 3–9 °C with respect to the external air temperatures, depending on the greenhouse cover material used.
The heat engine cycle, the heat removal cycle, and ergonomics of the control room displays
International Nuclear Information System (INIS)
Beltracchi, L.
1986-01-01
This paper discusses and illustrates the ergonomics of an integrated display, which will allow operators to monitor the heat engine cycle during normal operation of the plant, and the heat removal cycle during emergency operation of the plant. A computer-based iconic display is discussed as an overview to monitor these cycles. Specific emphasis is placed upon the process variables and process functions within each cycle, and the action of control systems and engineered safeguard systems within each cycle. This paper contains examples of display formats for the heat engine cycle and the heat removal cycle in a pressurized water reactor
Mathematics for physicists and engineers fundamentals and interactive study guide
Weltner, Klaus; Grosjean, Jean; Schuster, Peter
2009-01-01
Mathematics is the basic language in physics and engineering. It is an essential tool which first and second year students have to master as soon as possible. A lack of competence in mathematics is the main reason for failure and drop out in the beginning periods of study. This textbook offers an accessible and highly approved approach which is characterized by the combination of the textbook with a detailed study guide available online at extras.springer.com. This study guide divides the whole learning task into small units which the student is very likely to master successfully. Thus he or she is asked to read and study a limited section of the textbook and to return to the study guide afterwards. Working with the study guide his or her learning results are controlled, monitored and deepened by graded questions, exercises, repetitions and finally by problems and applications of the content studied. Since the degree of difficulties is slowly rising the students gain confidence and experience their own progre...
Heat Transfer Analysis of a Diesel Engine Head
Directory of Open Access Journals (Sweden)
M. Diviš
2003-01-01
Full Text Available This paper documents the research carried out at the Josef Božek Research Center of Engine and Automotive Engineering dealing with extended numerical stress/deformation analyses of engines parts loaded by heat and mechanical forces. It contains a detailed description of a C/28 series diesel engine head FE model and a discussion of heat transfer analysis tunning and results. The head model consisting of several parts allows a description of contact interaction in both thermal and mechanical analysis.
A Study of Ballast Water Treatment Using Engine Waste Heat
Balaji, Rajoo; Yaakob, Omar; Koh, Kho King; Adnan, Faizul Amri bin; Ismail, Nasrudin bin; Ahmad, Badruzzaman bin; Ismail, Mohd Arif bin
2018-05-01
Heat treatment of ballast water using engine waste heat can be an advantageous option complementing any proven technology. A treatment system was envisaged based on the ballast system of an existing, operational crude carrier. It was found that the available waste heat could raise the temperatures by 25 °C and voyage time requirements were found to be considerable between 7 and 12 days to heat the high volumes of ballast water. Further, a heat recovery of 14-33% of input energies from exhaust gases was recorded while using a test rig arrangement representing a shipboard arrangement. With laboratory level tests at temperature ranges of around 55-75 °C, almost complete species mortalities for representative phytoplankton, zooplankton and bacteria were observed while the time for exposure varied from 15 to 60 s. Based on the heat availability analyses for harvesting heat from the engine exhaust gases(vessel and test rig), heat exchanger designs were developed and optimized using Lagrangian method applying Bell-Delaware approaches. Heat exchanger designs were developed to suit test rig engines also. Based on these designs, heat exchanger and other equipment were procured and erected. The species' mortalities were tested in this mini-scale arrangement resembling the shipboard arrangement. The mortalities realized were > 95% with heat from jacket fresh water and exhaust gases alone. The viability of the system was thus validated.
Capture of Heat Energy from Diesel Engine Exhaust
Energy Technology Data Exchange (ETDEWEB)
Chuen-Sen Lin
2008-12-31
Diesel generators produce waste heat as well as electrical power. About one-third of the fuel energy is released from the exhaust manifolds of the diesel engines and normally is not captured for useful applications. This project studied different waste heat applications that may effectively use the heat released from exhaust of Alaskan village diesel generators, selected the most desirable application, designed and fabricated a prototype for performance measurements, and evaluated the feasibility and economic impact of the selected application. Exhaust flow rate, composition, and temperature may affect the heat recovery system design and the amount of heat that is recoverable. In comparison with the other two parameters, the effect of exhaust composition may be less important due to the large air/fuel ratio for diesel engines. This project also compared heat content and qualities (i.e., temperatures) of exhaust for three types of fuel: conventional diesel, a synthetic diesel, and conventional diesel with a small amount of hydrogen. Another task of this project was the development of a computer-aided design tool for the economic analysis of selected exhaust heat recovery applications to any Alaskan village diesel generator set. The exhaust heat recovery application selected from this study was for heating. An exhaust heat recovery system was fabricated, and 350 hours of testing was conducted. Based on testing data, the exhaust heat recovery heating system showed insignificant effects on engine performance and maintenance requirements. From measurements, it was determined that the amount of heat recovered from the system was about 50% of the heat energy contained in the exhaust (heat contained in exhaust was evaluated based on environment temperature). The estimated payback time for 100% use of recovered heat would be less than 3 years at a fuel price of $3.50 per gallon, an interest rate of 10%, and an engine operation of 8 hours per day. Based on experimental data
Performance evaluation and experiment system for waste heat recovery of diesel engine
International Nuclear Information System (INIS)
Wenzhi, Gao; Junmeng, Zhai; Guanghua, Li; Qiang, Bian; Liming, Feng
2013-01-01
In this paper, a waste heat recovery system is proposed where a high speed turbocharged diesel engine acts as the topper of a combined cycle with exhaust gases used for a bottoming Rankine cycle. The paper describes a mathematical model to evaluate the performance of Rankine cycle system with a reciprocating piston expander. The paper focuses on the performance evaluation and parameter selection of the heat exchanger and reciprocating piston expander that are suitable to waste heat recovery of ICE (internal combustion engine). The paper also describes the experimental setup and the preliminary results. The simulation results show that a proper intake pressure should be 4–5 MPa at its given mass flow rate of 0.015–0.021 kg/s depending on the waste heat recovery of a turbocharged diesel engine (80 kW/2590 rpm). The net power and net power rise rate at various ICE rotation speeds are calculated. The result shows that introducing heat recovery system can increase the engine power output by 12%, when diesel engine operates at 80 kW/2590 rpm. The preliminary experimental results indirectly prove the simulation model by two negative work loops in the P–V curve, under a low intake pressure and steam flow rate condition. - Highlights: • We investigate waste heat recovery through secondary fluid power cycle. • We establish a thermodynamic model of reciprocating steam engine. • We conduct the performance evaluation and experimental system development. • Primary parameters of the heat exchangers and expander are determined
Investigating and Developing Engineering Students' Mathematical Modelling and Problem-Solving Skills
Wedelin, Dag; Adawi, Tom; Jahan, Tabassum; Andersson, Sven
2015-01-01
How do engineering students approach mathematical modelling problems and how can they learn to deal with such problems? In the context of a course in mathematical modelling and problem solving, and using a qualitative case study approach, we found that the students had little prior experience of mathematical modelling. They were also inexperienced…
Optimal power and efficiency of quantum Stirling heat engines
Yin, Yong; Chen, Lingen; Wu, Feng
2017-01-01
A quantum Stirling heat engine model is established in this paper in which imperfect regeneration and heat leakage are considered. A single particle which contained in a one-dimensional infinite potential well is studied, and the system consists of countless replicas. Each particle is confined in its own potential well, whose occupation probabilities can be expressed by the thermal equilibrium Gibbs distributions. Based on the Schrödinger equation, the expressions of power output and efficiency for the engine are obtained. Effects of imperfect regeneration and heat leakage on the optimal performance are discussed. The optimal performance region and the optimal values of important parameters of the engine cycle are obtained. The results obtained can provide some guidelines for the design of a quantum Stirling heat engine.
Non-Markovian Investigation of an Autonomous Quantum Heat Engine
Goyal, Ketan
A systematic study of a quantum heat engine is presented in this thesis. In particular, we study heat conduction through a two-two level composite system, which is then connected to a photon cavity to extract work, forming an autonomous quantum heat engine. The question as to what extent quantum effects such as quantum coherence and correlations impact thermodynamic properties of such a system is addressed. The investigated heat engine has been previously studied using the popular Born-Markovian quantum master equation under weak internal coupling approximation. However, we show that the used approach is quite limited in addressing such problems as it is incapable of correctly accounting for the quantum effects. By using a non-Markovian approach involving hierarchical equations of motion, we show that quantum coherence and correlations between system and environments play a significant role in energy transfer processes of heat conduction and work.
A Complex Formula: Girls and Women in Science, Technology, Engineering and Mathematics in Asia
Salmon, Aliénor
2015-01-01
What factors might be causing the low participation of women Science, Technology, Engineering and Mathematics (STEM) fields? What can be done to attract more girls and women into STEM in Asia and beyond? The report, "A Complex Formula. Girls and Women in Science, Technology, Engineering and Mathematics in Asia", answers three fundamental…
Engineering Physics and Mathematics Division progress report for period ending August 31, 1989
International Nuclear Information System (INIS)
1989-12-01
This paper contains abstracts on research performed at the Engineering Physics and Mathematics Division of Oak Ridge National Laboratory. The areas covered are: mathematical science; nuclear-data measurement and evaluation; intelligent systems; nuclear analysis and shielding; and Engineering Physics Information Center
Engineering Physics and Mathematics Division progress report for period ending August 31, 1989
Energy Technology Data Exchange (ETDEWEB)
1989-12-01
This paper contains abstracts on research performed at the Engineering Physics and Mathematics Division of Oak Ridge National Laboratory. The areas covered are: mathematical science; nuclear-data measurement and evaluation; intelligent systems; nuclear analysis and shielding; and Engineering Physics Information Center. (LSP)
TDmat--Mathematics Diagnosis Evaluation Test for Engineering Sciences Students
Pinto, J. S.; Oliveira, M. P.; Anjo, A. B.; Pais, S. I. Vieira; Isidro, R. O.; Silva, M. H.
2007-01-01
Since 1989, the Mathematics Education Project (PmatE--Projecto Matematica Ensino) has developed several strategies to improve the success of students in Mathematics. The most important of these are mathematical games for all grades above primary school. The online evaluation of Mathematics subjects is one of PmatE's goals. The implementation of an…
Effect of different heat transfer models on HCCI engine simulation
International Nuclear Information System (INIS)
Neshat, Elaheh; Saray, Rahim Khoshbakhti
2014-01-01
Highlights: • A new multi zone model is developed for HCCI combustion modeling. • New heat transfer model is used for prediction of heat transfer in HCCI engines. • Model can predict engine combustion, performance and emission characteristics well. • Appropriate mass and heat transfer models cause to accurate prediction of CO, UHC and NOx. - Abstract: Heat transfer from engine walls has an important role on engine combustion, performance and emission characteristics. The main focus of this study is offering a new relation for calculation of convective heat transfer from in-cylinder charge to combustion chamber walls of HCCI engines and providing the ability of new model in comparison with the previous models. Therefore, a multi zone model is developed for homogeneous charge compression ignition engine simulation. Model consists of four different types of zones including core zone, boundary layer zone, outer zones, which are between core and boundary layer, and crevice zone. Conductive heat transfer and mass transfer are considered between neighboring zones. For accurate calculation of initial conditions at inlet valve closing, multi zone model is coupled with a single zone model, which simulates gas exchange process. Various correlations are used as convective heat transfer correlations. Woschni, modified Woschni, Hohenberg and Annand correlations are used as convective heat transfer models. The new convection model, developed by authors, is used, too. Comparative analyses are done to recognize the accurate correlation for prediction of engine combustion, performance and emission characteristics in a wide range of operating conditions. The results indicate that utilization of various heat transfer models, except for new convective heat transfer model, leads to significant differences in prediction of in-cylinder pressure and exhaust emissions. Using Woschni, Chang and new model, convective heat transfer coefficient increases near top dead center, sharply
The Dependency of Engineering Technology Student’s towards the Usage of Calculator in Mathematics
Directory of Open Access Journals (Sweden)
Hussin Nor Hafizah
2017-01-01
Full Text Available Calculators are one of the important technology used to solve mathematical computations. It also can be the tool for learning mathematics if it is used appropriately. However, too much depends on calculator can be harmful to students ability to solve simple mathematical problem. The purpose of this study is to examine the dependency of students in Faculty of Engineering Technology (FTK, Universiti Teknikal Malaysia Melaka, on the usage of calculator to solve the mathematical problems. A sample of 383 first year Engineering Technology (ET students’ taking mathematics subject are selected from five different course. Students were examined based on the results of Mathematic Competency Test and the survey from a questionnaire that covers questions regarding the students’ enjoyment on the usage of calculator and the usefulness of calculator in mathematic activities. The investigation yield a result showing that the students has a high dependency on using calculator to solve mathematical problem.
Generalized irreversible heat-engine experiencing a complex heat-transfer law
International Nuclear Information System (INIS)
Chen Lingen; Li Jun; Sun Fengrui
2008-01-01
The fundamental optimal relation between optimal power-output and efficiency of a generalized irreversible Carnot heat-engine is derived based on a generalized heat-transfer law, including a generalized convective heat-transfer law and a generalized radiative heat-transfer law, q ∝ (ΔT n ) m . The generalized irreversible Carnot-engine model incorporates several internal and external irreversibilities, such as heat resistance, bypass heat-leak, friction, turbulence and other undesirable irreversibility factors. The added irreversibilities, besides heat resistance, are characterized by a constant parameter and a constant coefficient. The effects of heat-transfer laws and various loss terms are analyzed. The results obtained corroborate those in the literature
Evaluation of heat transfer correlations for HCCI engine modeling
Soyhan, H.S.; Yasar, H.; Walmsley, H.; Head, B.; Kalghatgi, G.T.; Sorusbay, C.
2009-01-01
Combustion in HCCI engines is a controlled auto-ignition of well-mixed fuel, air and residual gas. The thermal conditions of the combustion chamber are governed by chemical kinetics strongly coupled with heat transfer from the hot gas to the walls. The heat losses have a critical effect on HCCI
Design procedures for heat-straightening repair : an engineering guide.
1992-12-01
This report summarizes over four years of research on heat-straightening repairs and provides a prototype engineering guide for the application of heat-straightening to bridge structures. It is based on the research results detailed in a companion re...
Randahl, Mira
2016-01-01
Doktorgradsavhandling It is usually assumed that the students at tertiary level work intensively and individually with the new mathematical concepts (Wood, 2001). In this context the mathematics textbook might be an important learning tool. This thesis addresses the issue of what factors might influence the role of the mathematics textbook as a learning tool. The study is situated in the context of the basic mathematics course taken by first-year engineering students. A b...
Performance analysis of diesel engine heat pump incorporated with heat recovery
International Nuclear Information System (INIS)
Shah, N.N.; Huang, M.J.; Hewitt, N.J.
2016-01-01
Highlights: • Diesel engine heat pump with heat recovery. • Water-to-water source heat pump based on R134a. • Possibility for different flow temperature for heat distribution system. • Possible retrofit application in off-gas or weak electricity network area. • Potential to diversify use of fossil fuel, primary energy and CO_2 emission savings. - Abstract: This paper presents experimental study of diesel engine heat pump (DEHP) system to find potential as retrofit technology in off-gas or weak electricity network area to replace existing gas/oil/electric heating system in domestic sector. Test set-up of diesel engine driven water-to-water heat pump system was built which included heat recovery arrangement from the engine coolant & exhaust gas. The system was designed to meet typical house heating demand in Northern Ireland. Performance of DEHP was evaluated to meet house-heating demand at different flow temperature (35, 45, 55 & 65 °C), a typical requirement of underfloor space heating, medium/high temperature radiators and domestic hot water. The performance was evaluated against four-evaporator water inlet temperature (0, 5, 10 & 15 °C) and at three different engine speed 1600, 2000 & 2400 rpm. Experiment results were analysed in terms of heating/cooling capacity, heat recovery, total heat output, primary energy ratio (PER), isentropic efficiency, etc. Test results showed that DEHP is able to meet house-heating demand with help of heat recovery with reduced system size. Heat recovery contributed in a range of 22–39% in total heat output. It is possible to achieve high flow temperature in a range of 74 °C with help of heat recovery. Overall system PER varied in a range of 0.93–1.33. Speed increment and flow temperature has significant impact on heat recovery, total heat output and PER. A case scenario with different flow temperature to match house-heating demand has been presented to show working potential with different heat distribution system
Geothermal heating a handbook of engineering economics
Harrison, R; Smarason, O B
2013-01-01
To date all books on geothermics have emphasized its use for generating electricity, with applications of lower grade resources for direct heating meriting only a brief chapter. This book brings together research from a range of scientific journals and 'grey' literature to produce the first comprehensive text on geothermal heating. Economics form an important part of the book. It provides a step by step analysis of the various ways in which thermal waters can be used to provide space heating and of the advantages and disadvantages of different approaches. The final section of the book provides
Mathematical model of heat transfer to predict distribution of hardness through the Jominy bar
International Nuclear Information System (INIS)
Lopez, E.; Hernandez, J. B.; Solorio, G.; Vergara, H. J.; Vazquez, O.; Garnica, F.
2013-01-01
The heat transfer coefficient was estimated at the bottom surface at Jominy bar end quench specimen by solution of the heat inverse conduction problem. A mathematical model based on the finite-difference method was developed to predict thermal paths and volume fraction of transformed phases. The mathematical model was codified in the commercial package Microsoft Visual Basic v. 6. The calculated thermal path and final phase distribution were used to evaluate the hardness distribution along the AISI 4140 Jominy bar. (Author)
Mathematical model development of heat and mass exchange processes in the outdoor swimming pool
M. V. Shaptala; D. E. Shaptala
2014-01-01
Purpose. Currently exploitation of outdoor swimming pools is often not cost-effective and, despite of their relevance, such pools are closed in large quantities. At this time there is no the whole mathematical model which would allow assessing qualitatively the effect of energy-saving measures. The aim of this work is to develop a mathematical model of heat and mass exchange processes for calculating basic heat and mass losses that occur during its exploitation. Methodology. The m...
Mohammadi, Bijan; Pironneau, Olivier; Cipolla, Vittorio
2016-01-01
This book presents papers surrounding the extensive discussions that took place from the ‘Variational Analysis and Aerospace Engineering’ workshop held at the Ettore Majorana Foundation and Centre for Scientific Culture in 2015. Contributions to this volume focus on advanced mathematical methods in aerospace engineering and industrial engineering such as computational fluid dynamics methods, optimization methods in aerodynamics, optimum controls, dynamic systems, the theory of structures, space missions, flight mechanics, control theory, algebraic geometry for CAD applications, and variational methods and applications. Advanced graduate students, researchers, and professionals in mathematics and engineering will find this volume useful as it illustrates current collaborative research projects in applied mathematics and aerospace engineering.
Rancic, Milica
2016-01-01
This book highlights the latest advances in engineering mathematics with a main focus on the mathematical models, structures, concepts, problems and computational methods and algorithms most relevant for applications in modern technologies and engineering. It addresses mathematical methods of algebra, applied matrix analysis, operator analysis, probability theory and stochastic processes, geometry and computational methods in network analysis, data classification, ranking and optimisation. The individual chapters cover both theory and applications, and include a wealth of figures, schemes, algorithms, tables and results of data analysis and simulation. Presenting new methods and results, reviews of cutting-edge research, and open problems for future research, they equip readers to develop new mathematical methods and concepts of their own, and to further compare and analyse the methods and results discussed. The book consists of contributed chapters covering research developed as a result of a focused interna...
Fuel system for diesel engine with multi-stage heated
Ryzhov, Yu N.; Kuznetsov, Yu A.; Kolomeichenko, A. V.; Kuznetsov, I. S.; Solovyev, R. Yu; Sharifullin, S. N.
2017-09-01
The article describes a fuel system of a diesel engine with a construction tractor multistage heating, allowing the use of pure rapeseed oil as a diesel engine fuel. The paper identified the kinematic viscosity depending on the temperature and composition of the mixed fuel, supplemented by the existing recommendations on the use of mixed fuels based on vegetable oils and developed the device allowing use as fuel for diesel engines of biofuels based on vegetable oils.
HEAT TRANSFER IN EXHAUST SYSTEM OF A COLD START ENGINE AT LOW ENVIRONMENTAL TEMPERATURE
Directory of Open Access Journals (Sweden)
Snežana D Petković
2010-01-01
Full Text Available During the engine cold start, there is a significantly increased emission of harmful engine exhaust gases, particularly at very low environmental temperatures. Therefore, reducing of emission during that period is of great importance for the reduction of entire engine emission. This study was conducted to test the activating speed of the catalyst at low environmental temperatures. The research was conducted by use of mathematical model and developed computer programme for calculation of non-stationary heat transfer in engine exhaust system. During the research, some of constructional parameters of exhaust system were adopted and optimized at environmental temperature of 22 C. The combination of design parameters giving best results at low environmental temperatures was observed. The results showed that the temperature in the environment did not have any significant influence on pre-catalyst light-off time.
Li, Shu-Nan; Cao, Bing-Yang
2017-09-01
The second law of thermodynamics governs the direction of heat transport, which provides the foundational definition of thermodynamic Clausius entropy. The definitions of entropy are further generalized for the phenomenological heat transport models in the frameworks of classical irreversible thermodynamics and extended irreversible thermodynamics (EIT). In this work, entropic functions from mathematics are combined with phenomenological heat conduction models and connected to several information-geometrical conceptions. The long-time behaviors of these mathematical entropies exhibit a wide diversity and physical pictures in phenomenological heat conductions, including the tendency to thermal equilibrium, and exponential decay of nonequilibrium and asymptotics, which build a bridge between the macroscopic and microscopic modelings. In contrast with the EIT entropies, the mathematical entropies expressed in terms of the internal energy function can avoid singularity paired with nonpositive local absolute temperature caused by non-Fourier heat conduction models.
Proceedings of the 1987 coatings for advanced heat engines workshop
Energy Technology Data Exchange (ETDEWEB)
1987-01-01
This Workshop was conducted to enhance communication among those involved in coating development for improved heat engine performance and durability. We were fortunate to have Bill Goward review the steady progress and problems encountered along the way in the use of thermal barrier coatings (TBC) in aircraft gas turbine engines. Navy contractors discussed their work toward the elusive goal of qualifying TBC for turbine airfoil applications. In the diesel community, Caterpillar and Cummins are developing TBC for combustion chamber components as part of the low heat rejection diesel engine concept. The diesel engine TBC work is based on gas turbine technology with a goal of more than twice the thickness used on gas turbine engine components. Adoption of TBC in production for diesel engines could justify a new generation of plasma spray coating equipment. Increasing interests in tribology were evident in this Workshop. Coatings have a significant role in reducing friction and wear under greater mechanical loadings at higher temperatures. The emergence of a high temperature synthetic lubricant could have an enormous impact on diesel engine design and operating conditions. The proven coating processes such as plasma spray, electron-beam physical vapor deposition, sputtering, and chemical vapor deposition have shown enhanced capabilities, particularly with microprocessor controls. Also, the newer coating schemes such as ion implantation and cathodic arc are demonstrating intriguing potential for engine applications. Coatings will play an expanding role in higher efficiency, more durable heat engines.
Endoreversible quantum heat engines in the linear response regime.
Wang, Honghui; He, Jizhou; Wang, Jianhui
2017-07-01
We analyze general models of quantum heat engines operating a cycle of two adiabatic and two isothermal processes. We use the quantum master equation for a system to describe heat transfer current during a thermodynamic process in contact with a heat reservoir, with no use of phenomenological thermal conduction. We apply the endoreversibility description to such engine models working in the linear response regime and derive expressions of the efficiency and the power. By analyzing the entropy production rate along a single cycle, we identify the thermodynamic flux and force that a linear relation connects. From maximizing the power output, we find that such heat engines satisfy the tight-coupling condition and the efficiency at maximum power agrees with the Curzon-Ahlborn efficiency known as the upper bound in the linear response regime.
Analysis of pre-heated fuel combustion and heat-emission dynamics in a diesel engine
Plotnikov, S. A.; Kartashevich, A. N.; Buzikov, S. V.
2018-01-01
The article explores the feasibility of diesel fuel pre-heating. The research goal was to obtain and analyze the performance diagrams of a diesel engine fed with pre-heated fuel. The engine was tested in two modes: at rated RPMs and at maximum torque. To process the diagrams the authors used technique developed by the Central Diesel Research Institute (CDRI). The diesel engine’s heat emission curves were obtained. The authors concluded that fuel pre-heating shortened the initial phase of the combustion process and moderated the loads, thus making it possible to boost a diesel engine’s mean effective pressure.
Irreversible thermodynamic analysis and application for molecular heat engines
Lucia, Umberto; Açıkkalp, Emin
2017-09-01
Is there a link between the macroscopic approach to irreversibility and microscopic behaviour of the systems? Consumption of free energy keeps the system away from a stable equilibrium. Entropy generation results from the redistribution of energy, momentum, mass and charge. This concept represents the essence of the thermodynamic approach to irreversibility. Irreversibility is the result of the interaction between systems and their environment. The aim of this paper is to determine lost works in a molecular engine and compare results with macro (classical) heat engines. Firstly, irreversible thermodynamics are reviewed for macro and molecular cycles. Secondly, irreversible thermodynamics approaches are applied for a quantum heat engine with -1/2 spin system. Finally, lost works are determined for considered system and results show that macro and molecular heat engines obey same limitations. Moreover, a quantum thermodynamic approach is suggested in order to explain the results previously obtained from an atomic viewpoint.
Heat exchanger operation in the externally heated air valve engine with separated settling chambers
International Nuclear Information System (INIS)
Kazimierski, Zbyszko; Wojewoda, Jerzy
2014-01-01
The crucial role in the externally heated air valve engine is played by its heat exchangers which work in a closed cycle. These are: a heater and a cooler and they are subject to a numerical analysis in the paper. Both of them are equipped with fixed volumes that are separate settling chambers causing that heat exchangers behave as almost stationary recuperators and analysis of the stationary behaviour is the main goal of the paper. Power and efficiency of the engine must be not lower than their averaged values for the same engine working in unsteady conditions. The results of calculations confirm such a statement. The pressure drop in the exchanger is another natural phenomenon presented. It has been overcome by use of additional blowers and the use of them is an additional focus of the presented analysis. A separation of settling chambers and additional blowers is a novelty in the paper. There is also a pre-heater applied in the engine which does not differ from well-known heat exchangers met in energy generation devices. The main objective of the paper is to find the behaviour of the engine model under stationary conditions of the heat exchangers and compare it with the non-stationary ones. - Highlights: • Externally heated air engine combined with forced working gas flow (supercharging). • Separate settling chambers allow for achieving stable and constant heat exchange parameters. • Pressure drop in heat exchangers overcome by additional blowers. • Reciprocating piston air engine, cam governing system, standard lubrication for externally heated engine. • Different fuels: oil, coal, gas, biomass also solar or nuclear energy
Atmospheric Circulations of Rocky Planets as Heat Engines
Koll, D. D. B.
2017-12-01
Rocky planets are extremely common in the galaxy and include Earth, Mars, Venus, and hundreds of exoplanets. To understand and compare the climates of these planets, we need theories that are general enough to accommodate drastically different atmospheric and planetary properties. Unfortunately, few such theories currently exist.For Earth, there is a well-known principle that its atmosphere resembles a heat engine - the atmosphere absorbs heat near the surface, at a hot temperature, and emits heat to space in the upper troposphere, at a cold temperature, which allows it to perform work and balance dissipative processes such as friction. However, previous studies also showed that Earth's hydrological cycle uses up a large fraction of the heat engine's work output, which makes it difficult to view other atmospheres as heat engines.In this work I extend the heat engine principle from Earth towards other rocky planets. I explore both dry and moist atmospheres in an idealized general circulation model (GCM), and quantify their work output using entropy budgets. First, I show that convection and turbulent heat diffusion are important entropy sources in dry atmospheres. I develop a scaling that accounts for its effects, which allows me to predict the strength of frictional dissipation in dry atmospheres. There are strong parallels between my scaling and so-called potential intensity theory, which is a seminal theory for understanding tropical cyclones on Earth. Second, I address how moisture affects atmospheric heat engines. Moisture modifies both the thermodynamic properties of air and releases latent heat when water vapor condenses. I explore the impact of both effects, and use numerical simulations to explore the difference between dry and moist atmospheric circulations across a wide range of climates.
Engineering Physics and Mathematics Division progress report for period ending December 31, 1994
International Nuclear Information System (INIS)
Sincovec, R.F.
1995-07-01
This report provides a record of the research activities of the Engineering Physics and Mathematics Division for the period January 1, 1993, through December 31, 1994. This report is the final archival record of the EPM Division. On October 1, 1994, ORELA was transferred to Physics Division and on January 1, 1995, the Engineering Physics and Mathematics Division and the Computer Applications Division reorganized to form the Computer Science and Mathematics Division and the Computational Physics and Engineering Division. Earlier reports in this series are identified on the previous pages, along with the progress reports describing ORNL's research in the mathematical sciences prior to 1984 when those activities moved into the Engineering Physics and Mathematics Division
Engineering Physics and Mathematics Division progress report for period ending December 31, 1994
Energy Technology Data Exchange (ETDEWEB)
Sincovec, R.F.
1995-07-01
This report provides a record of the research activities of the Engineering Physics and Mathematics Division for the period January 1, 1993, through December 31, 1994. This report is the final archival record of the EPM Division. On October 1, 1994, ORELA was transferred to Physics Division and on January 1, 1995, the Engineering Physics and Mathematics Division and the Computer Applications Division reorganized to form the Computer Science and Mathematics Division and the Computational Physics and Engineering Division. Earlier reports in this series are identified on the previous pages, along with the progress reports describing ORNL`s research in the mathematical sciences prior to 1984 when those activities moved into the Engineering Physics and Mathematics Division.
Mathematical model development of heat and mass exchange processes in the outdoor swimming pool
Directory of Open Access Journals (Sweden)
M. V. Shaptala
2014-12-01
Full Text Available Purpose. Currently exploitation of outdoor swimming pools is often not cost-effective and, despite of their relevance, such pools are closed in large quantities. At this time there is no the whole mathematical model which would allow assessing qualitatively the effect of energy-saving measures. The aim of this work is to develop a mathematical model of heat and mass exchange processes for calculating basic heat and mass losses that occur during its exploitation. Methodology. The method for determination of heat and mass loses based on the theory of similarity criteria equations is used. Findings. The main types of heat and mass losses of outdoor pool were analyzed. The most significant types were allocated and mathematically described. Namely: by evaporation of water from the surface of the pool, by natural and forced convection, by radiation to the environment, heat consumption for water heating. Originality. The mathematical model of heat and mass exchange process of the outdoor swimming pool was developed, which allows calculating the basic heat and mass loses that occur during its exploitation. Practical value. The method of determining heat and mass loses of outdoor swimming pool as a software system was developed and implemented. It is based on the mathematical model proposed by the authors. This method can be used for the conceptual design of energy-efficient structures of outdoor pools, to assess their use of energy-intensive and selecting the optimum energy-saving measures. A further step in research in this area is the experimental validation of the method of calculation of heat losses in outdoor swimming pools with its use as an example the pool of Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan. The outdoor pool, with water heating- up from the boiler room of the university, is operated year-round.
Nanoscale magnetic heat pumps and engines
Bauer, G.E.W.; Bretzel, S.; Brataas, A.; Tserkovnyak, Y.
2010-01-01
We present the linear-response matrix for a sliding domain wall in a rotatable magnetic nanowire, which is driven out of equilibrium by temperature and voltage bias, mechanical torque, and magnetic field. An expression for heat-current-induced domain-wall motion is derived. Application of Onsager’s
New Physical and Mathematical Model of Radiation Heat Transmission Inside Circular Furnace
Directory of Open Access Journals (Sweden)
V. I. Timoshpolsky
2004-01-01
Full Text Available Methods of solving problems concerning heat transmission by radiation are considered in the paper. The paper shows disadvantages of the existing techniques. A physical and mathematical model of a conjugate heat exchange has been developed to eliminate the above disadvantages.
Dual Expander Cycle Rocket Engine with an Intermediate, Closed-cycle Heat Exchanger
Greene, William D. (Inventor)
2008-01-01
A dual expander cycle (DEC) rocket engine with an intermediate closed-cycle heat exchanger is provided. A conventional DEC rocket engine has a closed-cycle heat exchanger thermally coupled thereto. The heat exchanger utilizes heat extracted from the engine's fuel circuit to drive the engine's oxidizer turbomachinery.
Quantum heat engine operating between thermal and spin reservoirs
Wright, Jackson S. S. T.; Gould, Tim; Carvalho, André R. R.; Bedkihal, Salil; Vaccaro, Joan A.
2018-05-01
Landauer's erasure principle is a cornerstone of thermodynamics and information theory [R. Landauer, IBM J. Res. Dev. 5, 183 (1961), 10.1147/rd.53.0183]. According to this principle, erasing information incurs a minimum energy cost. Recently, Vaccaro and Barnett [J. A. Vaccaro and S. M. Barnett, Proc. R. Soc. A 467, 1770 (2011), 10.1098/rspa.2010.0577] explored information erasure in the context of multiple conserved quantities and showed that the erasure cost can be solely in terms of spin angular momentum. As Landauer's erasure principle plays a fundamental role in heat engines, their result considerably widens the possible configurations that heat engines can have. Motivated by this, we propose here an optical heat engine that operates under a single thermal reservoir and a spin angular momentum reservoir coupled to a three-level system with two energy degenerate ground states. The proposed heat engine operates without producing waste heat and goes beyond the traditional Carnot engine where the working fluid is subjected to two thermal baths at different temperatures.
Design of Heat Exchanger for Ericsson-Brayton Piston Engine
Directory of Open Access Journals (Sweden)
Peter Durcansky
2014-01-01
Full Text Available Combined power generation or cogeneration is a highly effective technology that produces heat and electricity in one device more efficiently than separate production. Overall effectiveness is growing by use of combined technologies of energy extraction, taking heat from flue gases and coolants of machines. Another problem is the dependence of such devices on fossil fuels as fuel. For the combustion turbine is mostly used as fuel natural gas, kerosene and as fuel for heating power plants is mostly used coal. It is therefore necessary to seek for compensation today, which confirms the assumption in the future. At first glance, the obvious efforts are to restrict the use of largely oil and change the type of energy used in transport. Another significant change is the increase in renewable energy—energy that is produced from renewable sources. Among machines gaining energy by unconventional way belong mainly the steam engine, Stirling engine, and Ericsson engine. In these machines, the energy is obtained by external combustion and engine performs work in a medium that receives and transmits energy from combustion or flue gases indirectly. The paper deals with the principle of hot-air engines, and their use in combined heat and electricity production from biomass and with heat exchangers as primary energy transforming element.
Design of heat exchanger for Ericsson-Brayton piston engine.
Durcansky, Peter; Papucik, Stefan; Jandacka, Jozef; Holubcik, Michal; Nosek, Radovan
2014-01-01
Combined power generation or cogeneration is a highly effective technology that produces heat and electricity in one device more efficiently than separate production. Overall effectiveness is growing by use of combined technologies of energy extraction, taking heat from flue gases and coolants of machines. Another problem is the dependence of such devices on fossil fuels as fuel. For the combustion turbine is mostly used as fuel natural gas, kerosene and as fuel for heating power plants is mostly used coal. It is therefore necessary to seek for compensation today, which confirms the assumption in the future. At first glance, the obvious efforts are to restrict the use of largely oil and change the type of energy used in transport. Another significant change is the increase in renewable energy--energy that is produced from renewable sources. Among machines gaining energy by unconventional way belong mainly the steam engine, Stirling engine, and Ericsson engine. In these machines, the energy is obtained by external combustion and engine performs work in a medium that receives and transmits energy from combustion or flue gases indirectly. The paper deals with the principle of hot-air engines, and their use in combined heat and electricity production from biomass and with heat exchangers as primary energy transforming element.
Optimization of Heat Exchangers for Intercooled Recuperated Aero Engines
Directory of Open Access Journals (Sweden)
Dimitrios Misirlis
2017-03-01
Full Text Available In the framework of the European research project LEMCOTEC, a section was devoted to the further optimization of the recuperation system of the Intercooled Recuperated Aero engine (IRA engine concept, of MTU Aero Engines AG. This concept is based on an advanced thermodynamic cycle combining both intercooling and recuperation. The present work is focused only on the recuperation process. This is carried out through a system of heat exchangers mounted inside the hot-gas exhaust nozzle, providing fuel economy and reduced pollutant emissions. The optimization of the recuperation system was performed using computational fluid dynamics (CFD computations, experimental measurements and thermodynamic cycle analysis for a wide range of engine operating conditions. A customized numerical tool was developed based on an advanced porosity model approach. The heat exchangers were modeled as porous media of predefined heat transfer and pressure loss behaviour and could also incorporate major and critical heat exchanger design decisions in the CFD computations. The optimization resulted in two completely new innovative heat exchanger concepts, named as CORN (COnical Recuperative Nozzle and STARTREC (STraight AnnulaR Thermal RECuperator, which provided significant benefits in terms of fuel consumption, pollutants emission and weight reduction compared to more conventional heat exchanger designs, thus proving that further optimization potential for this technology exists.
Directory of Open Access Journals (Sweden)
Jose Manuel Diaz Moreno
2017-12-01
Full Text Available We describe a mathematical model for the industrial heating and cooling processes of a steel workpiece representing the steering rack of an automobile. The goal of steel heat treating is to provide a hardened surface on critical parts of the workpiece while keeping the rest soft and ductile in order to reduce fatigue. The high hardness is due to the phase transformation of steel accompanying the rapid cooling. This work takes into account both heating-cooling stage and viscoplastic model. Once the general mathematical formulation is derived, we can perform some numerical simulations.
A thermoacoustic-Stirling heat engine: detailed study
Backhaus; Swift
2000-06-01
A new type of thermoacoustic engine based on traveling waves and ideally reversible heat transfer is described. Measurements and analysis of its performance are presented. This new engine outperforms previous thermoacoustic engines, which are based on standing waves and intrinsically irreversible heat transfer, by more than 50%. At its most efficient operating point, it delivers 710 W of acoustic power to its resonator with a thermal efficiency of 0.30, corresponding to 41% of the Carnot efficiency. At its most powerful operating point, it delivers 890 W to its resonator with a thermal efficiency of 0.22. The efficiency of this engine can be degraded by two types of acoustic streaming. These are suppressed by appropriate tapering of crucial surfaces in the engine and by using additional nonlinearity to induce an opposing time-averaged pressure difference. Data are presented which show the nearly complete elimination of the streaming convective heat loads. Analysis of these and other irreversibilities show which components of the engine require further research to achieve higher efficiency. Additionally, these data show that the dynamics and acoustic power flows are well understood, but the details of the streaming suppression and associated heat convection are only qualitatively understood.
A thermoacoustic-Stirling heat engine: Detailed study
International Nuclear Information System (INIS)
Backhaus, S.; Swift, G. W.
2000-01-01
A new type of thermoacoustic engine based on traveling waves and ideally reversible heat transfer is described. Measurements and analysis of its performance are presented. This new engine outperforms previous thermoacoustic engines, which are based on standing waves and intrinsically irreversible heat transfer, by more than 50%. At its most efficient operating point, it delivers 710 W of acoustic power to its resonator with a thermal efficiency of 0.30, corresponding to 41% of the Carnot efficiency. At its most powerful operating point, it delivers 890 W to its resonator with a thermal efficiency of 0.22. The efficiency of this engine can be degraded by two types of acoustic streaming. These are suppressed by appropriate tapering of crucial surfaces in the engine and by using additional nonlinearity to induce an opposing time-averaged pressure difference. Data are presented which show the nearly complete elimination of the streaming convective heat loads. Analysis of these and other irreversibilities show which components of the engine require further research to achieve higher efficiency. Additionally, these data show that the dynamics and acoustic power flows are well understood, but the details of the streaming suppression and associated heat convection are only qualitatively understood. (c) 2000 Acoustical Society of America
Mathematical modelling of thermal and flow processes in vertical ground heat exchangers
Directory of Open Access Journals (Sweden)
Pater Sebastian
2017-12-01
Full Text Available The main task of mathematical modelling of thermal and flow processes in vertical ground heat exchanger (BHE-Borehole Heat Exchanger is to determine the unit of borehole depth heat flux obtainable or transferred during the operation of the installation. This assignment is indirectly associated with finding the circulating fluid temperature flowing out from the U-tube at a given inlet temperature of fluid in respect to other operational parameters of the installation.
Mančić Marko V.; Živković Dragoljub S.; Milosavljević Peđa M.; Todorović Milena N.
2014-01-01
Buildings with indoor swimming pools have a large energy footprint. The source of major energy loss is the swimming pool hall where air humidity is increased by evaporation from the pool water surface. This increases energy consumption for heating and ventilation of the pool hall, fresh water supply loss and heat demand for pool water heating. In this paper, a mathematical model of the swimming pool was made to assess energy demands of an indoor swimming po...
Finite-size effect on optimal efficiency of heat engines.
Tajima, Hiroyasu; Hayashi, Masahito
2017-07-01
The optimal efficiency of quantum (or classical) heat engines whose heat baths are n-particle systems is given by the strong large deviation. We give the optimal work extraction process as a concrete energy-preserving unitary time evolution among the heat baths and the work storage. We show that our optimal work extraction turns the disordered energy of the heat baths to the ordered energy of the work storage, by evaluating the ratio of the entropy difference to the energy difference in the heat baths and the work storage, respectively. By comparing the statistical mechanical optimal efficiency with the macroscopic thermodynamic bound, we evaluate the accuracy of the macroscopic thermodynamics with finite-size heat baths from the statistical mechanical viewpoint. We also evaluate the quantum coherence effect on the optimal efficiency of the cycle processes without restricting their cycle time by comparing the classical and quantum optimal efficiencies.
Molecular engineering problems in heat and mass transfer
International Nuclear Information System (INIS)
Kotake, S.
1991-01-01
As for developing, manufacturing and applying new materials of advanced functions such as high-performance devices and high-temperature materials, fundamental understanding of the phenomena from the standpoint of molecular and atomic levels has been required. In these problems, the processes of heat and mass transfer play an important role, being one of the rate-controlling factors. But the energy levels associated with heat and mass transfer are of the orders much less than those of chemical reaction, and it is not easy to understand the thermal problems on the molecular and atomic basis. This paper views the processes of heat and mass transfer from the dynamical motions of atom and molecule for thermal engineering problems. Especially, problems are considered of heat conduction in fine-ceramics, sintered materials of high heat conductivity or high heat-insulation, phase change of condensation in vapor deposition processes such as CVD and PVD, and radiation in laser processing
Work and power fluctuations in a critical heat engine
Holubec, Viktor; Ryabov, Artem
2017-09-01
We investigate fluctuations of output work for a class of Stirling heat engines with working fluid composed of interacting units and compare these fluctuations to an average work output. In particular, we focus on engine performance close to a critical point where Carnot's efficiency may be attained at a finite power as reported by M. Campisi and R. Fazio [Nat. Commun. 7, 11895 (2016), 10.1038/ncomms11895]. We show that the variance of work output per cycle scales with the same critical exponent as the heat capacity of the working fluid. As a consequence, the relative work fluctuation diverges unless the output work obeys a rather strict scaling condition, which would be very hard to fulfill in practice. Even under this condition, the fluctuations of work and power do not vanish in the infinite system size limit. Large fluctuations of output work thus constitute inseparable and dominant element in performance of the macroscopic heat engines close to a critical point.
Work and power fluctuations in a critical heat engine.
Holubec, Viktor; Ryabov, Artem
2017-09-01
We investigate fluctuations of output work for a class of Stirling heat engines with working fluid composed of interacting units and compare these fluctuations to an average work output. In particular, we focus on engine performance close to a critical point where Carnot's efficiency may be attained at a finite power as reported by M. Campisi and R. Fazio [Nat. Commun. 7, 11895 (2016)2041-172310.1038/ncomms11895]. We show that the variance of work output per cycle scales with the same critical exponent as the heat capacity of the working fluid. As a consequence, the relative work fluctuation diverges unless the output work obeys a rather strict scaling condition, which would be very hard to fulfill in practice. Even under this condition, the fluctuations of work and power do not vanish in the infinite system size limit. Large fluctuations of output work thus constitute inseparable and dominant element in performance of the macroscopic heat engines close to a critical point.
Mathematical Theory of Compressible Viscous, and Heat Conducting Fluids
Czech Academy of Sciences Publication Activity Database
Feireisl, Eduard
2007-01-01
Roč. 33, č. 4 (2007), s. 461-490 ISSN 0898-1221 R&D Projects: GA ČR GA201/05/0164 Institutional research plan: CEZ:AV0Z10190503 Keywords : compressible fluid * viscous fluid * entropy Subject RIV: BA - General Mathematics Impact factor: 0.720, year: 2007
Heat Transfer in Large Two-Stroke Marine Diesel Engines
DEFF Research Database (Denmark)
Jensen, Michael Vincent
Heat transfer between the cylinder gas and the piston surface during combustion in large two-stroke uniflow scavenged marine diesel engines has been investigated in the present work. The piston surface experiences a severe thermal load during combustion due to the close proximity of the combustion...... zone to the surface. At the same time, cooling of the piston crown is relatively complicated. This can cause large thermal stresses in the piston crown and weakening of the material strength, which may be critical as it can lead to formation of cracks. Information about the piston surface heat transfer...... is thus important for the engine manufactures. The piston surface heat transfer was studied in the event of impingement of hot combustion products on the piston during combustion, and an estimate was obtained of the peak heat flux level experienced on the piston surface. The investigation was carried out...
Shokati, Naser; Mohammadkhani, Farzad; Farrokhi, Navid; Ranjbar, Faramarz
2014-12-01
During manufacture of engines, evaluation of engine performance is essential. This is accomplished in test cells. During the test, a significant portion of heat energy released by the fuel is wasted. In this study, in order to recover these heat losses, Organic Rankine Cycle (ORC) is recommended. The study has been conducted assuming the diesel oil to be composed of a single hydrocarbon such as C12H26. The composition of exhaust gases (products of combustion) have been computed (and not determined experimentally) from the stoichiometric equation representing the combustion reaction. The test cell heat losses are recovered in three separate heat exchangers (preheater, evaporator and superheater). These heat exchangers are separately designed, and the whole system is analyzed from energy and exergy viewpoints. Finally, a parametric study is performed to investigate the effect of different variables on the system performance characteristics such as the ORC net power, heat exchangers effectiveness, the first law efficiency, exergy destruction and heat transfer surfaces. The results of the study show that by utilizing ORC, heat recovery equivalent to 8.85 % of the engine power is possible. The evaporator has the highest exergy destruction rate, while the pump has the lowest among the system components. Heat transfer surfaces are calculated to be 173.6, 58.7, and 11.87 m2 for the preheater, evaporator and superheater, respectively.
Science, Engineering, and Mathematics (SEM) at the Timbuktu Academy
2005-07-31
Science (AAAS) and the first Standards of the National Council of Teachers o f Mathematics ( NCTM ) both appeared in 1989 . They were followed by Scope...National Council of Teachers of Mathematics ( NCTM , 1989, 1991 , and 1995), Science for All Americans (Project 2061) and the Benchmarks of the America n...Documents, Mail Stop SSOP, Washington, DC, 20402-9328 . National Council of Teachers of Mathematics ( NCTM ) . Curriculum and Evaluation Standard s for School
Saadon, S.; Abu Talib, A. R.
2016-10-01
Due to energy shortage and global warming, issues of energy saving have become more important. To increase the energy efficiency and reduce the fuel consumption, waste heat recovery is a significant method for energy saving. The organic Rankine cycle (ORC) has great potential to recover the waste heat from the core jet exhaust of a turbofan engine and use it to produce power. Preliminary study of the design concept and thermodynamic performance of this ORC system would assist researchers to predict the benefits of using the ORC system to extract the exhaust heat engine. In addition, a mathematical model of the heat transfer of this ORC system is studied and developed. The results show that with the increment of exhaust heat temperature, the mass flow rate of the working fluid, net power output and the system thermal efficiency will also increase. Consequently, total consumption of jet fuel could be significantly saved as well.
Insoluble Coatings for Stirling Engine Heat Pipe Condenser Surfaces
Dussinger, Peter M.; Lindemuth, James E.
1997-01-01
The principal objective of this Phase 2 SBIR program was to develop and demonstrate a practically insoluble coating for nickel-based superalloys for Stirling engine heat pipe applications. Specific technical objectives of the program were: (1) Determine the solubility corrosion rates for Nickel 200, Inconel 718, and Udimet 72OLI in a simulated Stirling engine heat pipe environment, (2) Develop coating processes and techniques for capillary groove and screen wick structures, (3) Evaluate the durability and solubility corrosion rates for capillary groove and screen wick structures coated with an insoluble coating in cylindrical heat pipes operating under Stirling engine conditions, and (4) Design and fabricate a coated full-scale, partial segment of the current Stirling engine heat pipe for the Stirling Space Power Convertor program. The work effort successfully demonstrated a two-step nickel aluminide coating process for groove wick structures and interior wall surfaces in contact with liquid metals; demonstrated a one-step nickel aluminide coating process for nickel screen wick structures; and developed and demonstrated a two-step aluminum-to-nickel aluminide coating process for nickel screen wick structures. In addition, the full-scale, partial segment was fabricated and the interior surfaces and wick structures were coated. The heat pipe was charged with sodium, processed, and scheduled to be life tested for up to ten years as a Phase 3 effort.
Active learning increases student performance in science, engineering, and mathematics.
Freeman, Scott; Eddy, Sarah L; McDonough, Miles; Smith, Michelle K; Okoroafor, Nnadozie; Jordt, Hannah; Wenderoth, Mary Pat
2014-06-10
To test the hypothesis that lecturing maximizes learning and course performance, we metaanalyzed 225 studies that reported data on examination scores or failure rates when comparing student performance in undergraduate science, technology, engineering, and mathematics (STEM) courses under traditional lecturing versus active learning. The effect sizes indicate that on average, student performance on examinations and concept inventories increased by 0.47 SDs under active learning (n = 158 studies), and that the odds ratio for failing was 1.95 under traditional lecturing (n = 67 studies). These results indicate that average examination scores improved by about 6% in active learning sections, and that students in classes with traditional lecturing were 1.5 times more likely to fail than were students in classes with active learning. Heterogeneity analyses indicated that both results hold across the STEM disciplines, that active learning increases scores on concept inventories more than on course examinations, and that active learning appears effective across all class sizes--although the greatest effects are in small (n ≤ 50) classes. Trim and fill analyses and fail-safe n calculations suggest that the results are not due to publication bias. The results also appear robust to variation in the methodological rigor of the included studies, based on the quality of controls over student quality and instructor identity. This is the largest and most comprehensive metaanalysis of undergraduate STEM education published to date. The results raise questions about the continued use of traditional lecturing as a control in research studies, and support active learning as the preferred, empirically validated teaching practice in regular classrooms.
Quantum Heat Engine and Negative Boltzmann Temperature
International Nuclear Information System (INIS)
Xi Jing-Yi; Quan Hai-Tao
2017-01-01
To clarify the ambiguity on negative Boltzmann temperature in literature, we study the Carnot and the Otto cycle with one of the heat reservoirs at the negative Boltzmann temperature based on a canonical ensemble description. The work extraction, entropy production and the efficiency of these cycles are explored. Conditions for constructing and properties of these thermodynamic cycles are elucidated. We find that the apparent “violation” of the second law of thermodynamics in these cycles are due to the fact that the traditional definition of thermodynamic efficiency is inappropriate in this situation. When properly understanding the efficiency and the adiabatic processes, in which the system crosses over “absolute ZERO” in a limit sense, the Carnot cycle with one of the heat reservoirs at a negative Boltzmann temperature can be understood straightforwardly, and it contradicts neither the second nor the third law of thermodynamics. Hence, negative Boltzmann temperature is a consistent concept in thermodynamics. We use a two-level system and an Ising spin system to illustrate our central results. (paper)
Nonstationary heat flow in the piston of the turbocharged engine
Directory of Open Access Journals (Sweden)
Piotr GUSTOF
2010-01-01
Full Text Available In this study the numeric computations of nonstationary heat flow in form of temperature distribution on characteristic surfaces of the piston of the turbocharged engine at the beginning phase its work was presented. The computations were performed for fragmentary load engine by means of the two-zone combustion model, the boundary conditions of III kind and the finite elements method (FEM by using of COSMOS/M program.
INVOLVING STUDENTS IN RESEARCH AS A FORM OF INTEGRATION OF ENGINEERING WITH MATHEMATICAL EDUCATION
Directory of Open Access Journals (Sweden)
Viktor M. Fedoseyev
2016-03-01
Full Text Available Introduction: questions of integration of mathematical with engineering training in educational process of higher education institution are explored. The existing technologies of the integrated training are analyzed, and the project-oriented direction is distinguished. Research involving students as an organisational and methodical form of training bachelors of the technical speciali sations is discussed. Materials and Methods: results of article are based on researches of tendencies of development of technical and mathematical education, works on the theory and methodology of pedagogical integration, methodology of mathematics and technical science. Methods of historical and pedagogical research, analytical, a method of mathematical modeling were used. Results: the main content of the paper is to make discussion of experience in developing and using integrated educational tasks in real educational process. Discussion is based on a specific technological assignment including a number of mathematical tasks used as a subject of research for students. In the assignment a special place is allocated to the questions reflecting the interplay of a technical task with a mathematical method of research highlighting the objective significance of mathematics as a method to solve engineering problems. Discussion and Conclusions: the paper gives reasons to conditions for using research work with students as an organisational and methodical form of integrated training in mathematics. In realisation of educational technology it is logical to apply the method of projects. It is necessary to formulate a task as an engineering project: to set an engineering objective of research, to formulate specifications; to differentiate between engineering and mathematical tasks of the project, to make actual interrelations between them; the mathematical part of the project has to be a body of research; assessment of the project must be carried out not only accounting for
Heat recovery from a cement plant with a Marnoch Heat Engine
International Nuclear Information System (INIS)
Saneipoor, P.; Naterer, G.F.; Dincer, I.
2011-01-01
This paper examines the performance of a new Marnoch Heat Engine (MHE) that recovers waste heat from within a typical cement plant. Two MHE units with compressed air as the working fluid are installed to recover the waste heat. The first unit on the main stack has four pairs of shell and tube heat exchangers. The second heat recovery unit is installed on a clinker quenching system. This unit operates with three pairs of shell and tube heat exchangers. The recovered heat is converted to electricity through the MHE system and used internally within the cement plant. A predictive model and results are presented and discussed. The results show the promising performance of the MHE's capabilities for efficient generation of electricity from waste heat sources in a cement plant. The new heat recovery system increases the efficiency of the cement plant and lowers the CO 2 emissions from the clinker production process. Moreover, it reduces the amount of waste heat to the environment and lowers the temperature of the exhaust gases. - Highlights: → This paper examines the thermodynamic performance of a new Marnoch Heat Engine (MHE) that recovers waste heat to produce electricity and improve the operating efficiency of a typical cement plant. → The first unit of the MHE on the main stack has four pairs of shell and tube heat exchangers and the second heat recovery unit is installed on a clinker quenching system. → Both predicted and experimental results demonstrate the promising performance of the MHE's capabilities for efficient generation of electricity from waste heat sources in a cement plant.
International Nuclear Information System (INIS)
Li, X.; He, X.; Lv, J.; Wu, Y.; Luo, Y.; Chen, H.
2013-01-01
High intensive microwave pretreatment is a new method to modify wood for the fabrication of wood-based nano composites. Based on the physical law on heat transfer, a mathematical model to describe the temperature profiles within wood heated by high intensive microwave was established and simulated in this research. The results showed that the temperature profiles within wood were related to microwave heating methods; The temperature inside wood firstly increased and then gradually decreased along the direction of microwave transmission when the unilateral microwave heating was applied, and the temperature difference along the thickness direction of wood was very significant; The temperature with wood firstly increased and then gradually decreased from the wood surface to interior when the bilateral microwave heating was applied. Compared with the unilateral microwave heating, bilateral microwave heating is a better microwave heating method for the more uniform wood microwave pretreatment.
Ways of Thinking, Ways of Seeing Mathematical and other Modelling in Engineering and Technology
Dillon, Chris
2012-01-01
This fascinating book examines some of the characteristics of technological/engineering models that are likely to be unfamiliar to those who are interested primarily in the history and philosophy of science and mathematics, and which differentiate technological models from scientific and mathematical ones. Themes that will be highlighted include: • the role of language: the models developed for engineering design have resulted in new ways of talking about technological systems • communities of practice: related to the previous point, particular engineering communities have particular ways of sharing and developing knowledge • graphical (re)presentation: engineers have developed many ways of reducing quite complex mathematical models to more simple representations • reification: highly abstract mathematical models are turned into ‘objects’ that can be manipulated almost like components of a physical system • machines: not only the currently ubiquitous digital computer, but also older analogue dev...
Science, Technology, Engineering, and Mathematics (STEM) Education Issues and Legislative Options
National Research Council Canada - National Science Library
Kuenzi, Jeffrey J; Matthews, Christine M; Mangan, Bonnie F
2006-01-01
There is growing concern that the United States is not preparing a sufficient number of students, teachers, and practitioners in the areas of science, technology, engineering, and mathematics (STEM...
Mathematical Modelling in Engineering: A Proposal to Introduce Linear Algebra Concepts
Cárcamo Bahamonde, Andrea; Gómez Urgelles, Joan; Fortuny Aymemí, Josep
2016-01-01
The modern dynamic world requires that basic science courses for engineering, including linear algebra, emphasise the development of mathematical abilities primarily associated with modelling and interpreting, which are not exclusively calculus abilities. Considering this, an instructional design was created based on mathematical modelling and…
Online mathematics education: E-math for first year engineering students
DEFF Research Database (Denmark)
Markvorsen, Steen; Schmidt, Karsten
2012-01-01
We consider the technology enhanced learning of first year engineering mathematics and in particular the application of E-learning objects and principles in the course Mathematics 1 which has a yearly intake of 750 students at the technical University of Denmark. We show that with non-linear mult...
Carr, M.; Fidalgo, C.; Bigotte de Almeida, M. E.; Branco, J. R.; Santos, V.; Murphy, E.; Ní Fhloinn, E.
2015-01-01
Concern has been expressed throughout Europe about the significant deficiencies in the basic mathematical skills of many engineering undergraduates. Mathematics diagnostic tests in the UK, Ireland and Portugal have shown these shortcomings, which provide a challenge to those striving to introduce more innovative educational practices into…
Air Force-Wide Needs for Science, Technology, Engineering, and Mathematics (STEM) Academic Degrees
2014-01-01
anthropology (0190), mathematical statistics (1529), general math (AFIT faculty only), metallurgy (1321), and actuarial science (1510). 97 Tier II. Few...linking or frEE DownloAD At www.rand.org C O R P O R A T I O N Research Report Air Force–Wide Needs for Science , Technology, Engineering, and...00-00-2014 4. TITLE AND SUBTITLE Air Force-Wide Needs for Science , Technology, Engineering, and Mathematics (STEM) Academic Degrees 5a. CONTRACT
Waste Heat Recovery from a High Temperature Diesel Engine
Adler, Jonas E.
Government-mandated improvements in fuel economy and emissions from internal combustion engines (ICEs) are driving innovation in engine efficiency. Though incremental efficiency gains have been achieved, most combustion engines are still only 30-40% efficient at best, with most of the remaining fuel energy being rejected to the environment as waste heat through engine coolant and exhaust gases. Attempts have been made to harness this waste heat and use it to drive a Rankine cycle and produce additional work to improve efficiency. Research on waste heat recovery (WHR) demonstrates that it is possible to improve overall efficiency by converting wasted heat into usable work, but relative gains in overall efficiency are typically minimal ( 5-8%) and often do not justify the cost and space requirements of a WHR system. The primary limitation of the current state-of-the-art in WHR is the low temperature of the engine coolant ( 90 °C), which minimizes the WHR from a heat source that represents between 20% and 30% of the fuel energy. The current research proposes increasing the engine coolant temperature to improve the utilization of coolant waste heat as one possible path to achieving greater WHR system effectiveness. An experiment was performed to evaluate the effects of running a diesel engine at elevated coolant temperatures and to estimate the efficiency benefits. An energy balance was performed on a modified 3-cylinder diesel engine at six different coolant temperatures (90 °C, 100 °C, 125 °C, 150 °C, 175 °C, and 200 °C) to determine the change in quantity and quality of waste heat as the coolant temperature increased. The waste heat was measured using the flow rates and temperature differences of the coolant, engine oil, and exhaust flow streams into and out of the engine. Custom cooling and engine oil systems were fabricated to provide adequate adjustment to achieve target coolant and oil temperatures and large enough temperature differences across the
Energy Technology Data Exchange (ETDEWEB)
Stakhov, A.P. [International Club of the Golden Section, 6 McCreary Trail, Bolton, ON, L7E 2C8 (Canada)] e-mail: goldenmuseum@rogers.com
2005-10-01
The 'Dichotomy Principle' and the classical 'Golden Section Principle' are two of the most important principles of Nature, Science and also Art. The Generalized Principle of the Golden Section that follows from studying the diagonal sums of the Pascal triangle is a sweeping generalization of these important principles. This underlies the foundation of 'Harmony Mathematics', a new proposed mathematical direction. Harmony Mathematics includes a number of new mathematical theories: an algorithmic measurement theory, a new number theory, a new theory of hyperbolic functions based on Fibonacci and Lucas numbers, and a theory of the Fibonacci and 'Golden' matrices. These mathematical theories are the source of many new ideas in mathematics, philosophy, botanic and biology, electrical and computer science and engineering, communication systems, mathematical education as well as theoretical physics and physics of high energy particles.
International Nuclear Information System (INIS)
Stakhov, A.P.
2005-01-01
The 'Dichotomy Principle' and the classical 'Golden Section Principle' are two of the most important principles of Nature, Science and also Art. The Generalized Principle of the Golden Section that follows from studying the diagonal sums of the Pascal triangle is a sweeping generalization of these important principles. This underlies the foundation of 'Harmony Mathematics', a new proposed mathematical direction. Harmony Mathematics includes a number of new mathematical theories: an algorithmic measurement theory, a new number theory, a new theory of hyperbolic functions based on Fibonacci and Lucas numbers, and a theory of the Fibonacci and 'Golden' matrices. These mathematical theories are the source of many new ideas in mathematics, philosophy, botanic and biology, electrical and computer science and engineering, communication systems, mathematical education as well as theoretical physics and physics of high energy particles
VHTR engineering design study: intermediate heat exchanger program. Final report
International Nuclear Information System (INIS)
1976-11-01
The work reported is the result of a follow-on program to earlier Very High Temperature Reactor (VHTR) studies. The primary use of the VHTR is to provide heat for various industrial processes, such as hydrocarbon reforming and coal gasification. For many processes the use of an intermediate heat transfer barrier between the reactor coolant and the process is desirable; for some processes it is mandatory. Various intermediate heat exchanger (IHX) concepts for the VHTR were investigated with respect to safety, cost, and engineering design considerations. The reference processes chosen were steam-hydrocarbon reforming, with emphasis on the chemical heat pipe, and steam gasification of coal. The study investigates the critically important area of heat transfer between the reactor coolant, helium, and the various chemical processes
A study of competence in mathematics and mechanics in an engineering curriculum
Munns, Andrew
2017-11-01
Professional bodies expect engineers to show competence in both mathematics and engineering topics such as mechanics, using their abilities in both of these to solve problems. Yet within engineering programmes there is a phenomenon known as 'The Mathematics Problem', with students not demonstrating understanding of the subject. This paper will suggest that students are constructing different concept images in engineering and mathematics, based on their perception of either the use or exchange-value for the topics. Using a mixed methods approach, the paper compares 10 different types of concept image constructed by students, which suggests that familiar procedural images are preferred in mathematics. In contrast strategic and conceptual images develop for mechanics throughout the years of the programme, implying that different forms of competence are being constructed by students between the two subjects. The paper argues that this difference is attributed to the perceived use-value of mechanics in the career of the engineer, compared to the exchange-value associated with mathematics. Questions are raised about the relevance of current definitions of competence given that some routine mathematical operations previously performed by engineers are now being replaced by technology, in the new world of work.
Optimal Control of Diesel Engines with Waste Heat Recovery System
Willems, F.P.T.; Donkers, M.C.F.; Kupper, F.
2014-01-01
This study presents an integrated energy and emission management strategy for a Euro-VI diesel engine with Waste Heat Recovery (WHR) system. This Integrated Powertrain Control (IPC) strategy optimizes the CO2-NOx trade-off by minimizing the operational costs associated with fuel and AdBlue
Optimal control of diesel engines with waste heat recovery systems
Willems, F.P.T.; Donkers, M.C.F.; Kupper, F.; Waschl, H.; Kolmanovsky, I.; Steinbuch, M.; Del Re, L.
2014-01-01
This study presents an integrated energy and emission management strategy for a Euro-VI diesel engine with Waste Heat Recovery (WHR) system. This Integrated Powertrain Control (IPC) strategy optimizes the CO 2 - NO x trade-off by minimizing the operational costs associated with fuel and AdBlue
Optimization of powered Stirling heat engine with finite speed thermodynamics
International Nuclear Information System (INIS)
Ahmadi, Mohammad H.; Ahmadi, Mohammad Ali; Pourfayaz, Fathollah; Bidi, Mokhtar; Hosseinzade, Hadi; Feidt, Michel
2016-01-01
Highlights: • Based on finite speed method and direct method, the optimal performance is investigated. • The effects of major parameters on the optimal performance are investigated. • The accuracy of the results was compared with previous works. - Abstract: Popular thermodynamic analyses including finite time thermodynamic analysis was lately developed based upon external irreversibilities while internal irreversibilities such as friction, pressure drop and entropy generation were not considered. The aforementioned disadvantage reduces the reliability of the finite time thermodynamic analysis in the design of an accurate Stirling engine model. Consequently, the finite time thermodynamic analysis could not sufficiently satisfy researchers for implementing in design and optimization issues. In this study, finite speed thermodynamic analysis was employed instead of finite time thermodynamic analysis for studying Stirling heat engine. The finite speed thermodynamic analysis approach is based on the first law of thermodynamics for a closed system with finite speed and the direct method. The effects of heat source temperature, regenerating effectiveness, volumetric ratio, piston stroke as well as rotational speed are included in the analysis. Moreover, maximum output power in optimal rotational speed was calculated while pressure losses in the Stirling engine were systematically considered. The result reveals the accuracy and the reliability of the finite speed thermodynamic method in thermodynamic analysis of Stirling heat engine. The outcomes can help researchers in the design of an appropriate and efficient Stirling engine.
Engineering and economic aspects of centalized heating from nuclear boilers
International Nuclear Information System (INIS)
Emel'yanov, I.Ya.; Baturov, B.B.; Korytnikov, V.P.; Koryakin, Yu.I.; Chernyaev, V.A.; Kovylyanskij, Ya.A.; Galaktionov, I.V.
1979-01-01
Some engineering and economic aspects for deployment of centralized nuclear boilers (NB) in the USSR are considered. Engineering, maintenance and economic features of NB as compared to organic-fuelled boilers and nuclear thermal power plants are discussed. Among major factors governing economic efficiency of NB underlined are oraganic fuel costs, reactor unit power, location relative to heat-consuming centres and capacity factor. It is concluded that NB can be economical for heating large consumers (more than 1500 G kal/hr). At the periphery NB can be competitive already at reactor unit power of several MWth. The development of HTGR type reactor-based nuclear-chemical boilers and lines for heat transport in a chemically bound state (e.g., CH 4 → H 2 +CO 2 +CO → CH 4 ) opens the way for a substantial breakthrow in the centralized NB efficiency
Performance analysis of a thermosize micro/nano heat engine
International Nuclear Information System (INIS)
Nie Wenjie; He Jizhou
2008-01-01
In a recent paper [A. Sisman, I. Muller, Phys. Lett. A 320 (2004) 360] the thermodynamic properties of ideal gases confined in a narrow box were examined theoretically. The so-called 'thermosize effects' similar to thermoelectric effects, such as Seebeck-like thermosize effect, Peltier-like thermosize effect and Thomson-like thermosize effect, were analyzed. Like the thermoelectric generator, based on the thermosize effects we have established a model of micro/nano scaled ideal gas heat engine cycle which includes two isothermal and two isobaric processes. The expressions of power output and efficiency of this cycle in the two cases of reversible and irreversible heat exchange are derived and the optimal performance characteristics of the heat engine is discussed by some numerical example. The results obtained here will provide theoretical guidance for the design of micro/nano scaled device
Understanding Immunology via Engineering Design: The Role of Mathematical Prototyping
Directory of Open Access Journals (Sweden)
David J. Klinke
2012-01-01
type 1 diabetes and the dynamics of dendritic cells in the lung. This paper is intended to illustrate some of the nuances associated with applying mathematical modeling to improve understanding of the dynamics of disease progression in humans.
Heat engine in the three-dimensional spacetime
Energy Technology Data Exchange (ETDEWEB)
Mo, Jie-Xiong [Institute of Theoretical Physics, Lingnan Normal University,Zhanjiang, 524048, Guangdong (China); Department of Physics, Lingnan Normal University,Zhanjiang, 524048, Guangdong (China); Liang, Feng [Department of Physics, Lingnan Normal University,Zhanjiang, 524048, Guangdong (China); Li, Gu-Qiang [Institute of Theoretical Physics, Lingnan Normal University,Zhanjiang, 524048, Guangdong (China); Department of Physics, Lingnan Normal University,Zhanjiang, 524048, Guangdong (China)
2017-03-02
We define a kind of heat engine via three-dimensional charged BTZ black holes. This case is quite subtle and needs to be more careful. The heat flow along the isochores does not equal to zero since the specific heat C{sub V}≠0 and this point completely differs from the cases discussed before whose isochores and adiabats are identical. So one cannot simply apply the paradigm in the former literatures. However, if one introduces a new thermodynamic parameter associated with the renormalization length scale, the above problem can be solved. We obtain the analytical efficiency expression of the three-dimensional charged BTZ black hole heat engine for two different schemes. Moreover, we double check with the exact formula. Our result presents the first specific example for the sound correctness of the exact efficiency formula. We argue that the three-dimensional charged BTZ black hole can be viewed as a toy model for further investigation of holographic heat engine. Furthermore, we compare our result with that of the Carnot cycle and extend the former result to three-dimensional spacetime. In this sense, the result in this paper would be complementary to those obtained in four-dimensional spacetime or ever higher. Last but not the least, the heat engine efficiency discussed in this paper may serve as a criterion to discriminate the two thermodynamic approaches introduced in ref. https://www.doi.org/10.1103/PhysRevD.92.124069 and our result seems to support the approach which introduces a new thermodynamic parameter R=r{sub 0}.
Melnik, Roderick
2015-01-01
Illustrates the application of mathematical and computational modeling in a variety of disciplines With an emphasis on the interdisciplinary nature of mathematical and computational modeling, Mathematical and Computational Modeling: With Applications in the Natural and Social Sciences, Engineering, and the Arts features chapters written by well-known, international experts in these fields and presents readers with a host of state-of-the-art achievements in the development of mathematical modeling and computational experiment methodology. The book is a valuable guide to the methods, ideas,
Utilisation of diesel engine waste heat by Organic Rankine Cycle
International Nuclear Information System (INIS)
Kölsch, Benedikt; Radulovic, Jovana
2015-01-01
In this paper, three different organic liquids were investigated as potential working fluids in an Organic Rankine Cycle. Performance of Methanol, Toluene and Solkatherm SES36 was modelled in an ORC powered by a diesel engine waste heat. The ORC model consists of a preheater, evaporator, superheater, turbine, pump and two condensers. With variable maximum cycle temperatures and high cycle pressures, the thermal efficiency, net power output and overall heat transfer area have been evaluated. Methanol was found to have the best thermal performance, but also required the largest heat transfer area. While Toluene achieved lower thermal efficiency, it showed great work potential at high pressures and relatively low temperatures. Our model identified the risks associated with employing these fluids in an ORC: methanol condensing during the expansion and toluene not sufficiently superheated at the turbine inlet, which can compromise the cycle operation. The best compromise between the size of heat exchanger and thermodynamic performance was found for Methanol ORC at intermediate temperatures and high pressures. Flammability and toxicity, however, remain the obstacles for safe implementation of both fluids in ORC systems. - Highlights: • ORC powered by diesel-engine waste heat was developed. • Methanol, Toluene and Solkatherm were considered as working fluids. • Methanol was selected due to the best overall thermal performance. • Optimal cycle operating parameters and heat exchanger area were evaluated
International Nuclear Information System (INIS)
Khairnasov, S.M.; Zaripov, V.K.; Passamakin, B.M. et al.
2013-01-01
This paper presents the results of studies into the heat-engineering characteristics of a flat heat solar collector based on aluminum heat pipes that is designed to be used in building facades. The principle of work and the structure of the solar collector are considered; the results of its comparison with a traditional flat solar collector are presented. The studies were performed at a heat carrier temperature range of +10 - +30 degree C and at a solar heat flow density of 400 - 1000 W/m 2 . The obtained experimental heat-engineering characteristics of the collector based on heat pipes show that they are at a level of traditional flow solar collectors; for example, its efficiency is 0.65 - 0.73. Meanwhile, the hydraulic resistance of the structure with heat pipes is by a factor of 2 - 2.4 smaller and ensures a high level of scalability, reliability, and maintainability, which is important when using it as an element of facade constructions of solar heat systems. (author)
Heat transfer characteristics of some oils used for engine cooling
International Nuclear Information System (INIS)
Abou-Ziyan, Hosny Z.
2004-01-01
This paper reports the results of an experimental investigation of heat transfer from a cast iron test specimen to engine oils under boiling conditions. The work is aimed at evaluating the thermal characteristics of some engine oils in contact with high temperature parts in internal combustion engines. Three mono-grade oils and two multi-grade oils are examined at heat fluxes from about 30 to more than 400 kW/m 2 for bulk temperatures of 40, 60, 80, 100, 125, 150 and 175 deg. C. The considered oils are analyzed and tested according to some ASTM standards to determine their additives concentration and to obtain some of their thermophysical properties. The results indicated that oil additives, oil properties and bulk temperatures have substantial effects on the oil characteristics. The boiling heat flux, for the best oil, rises by a factor of 1.65 as the bulk temperature decreases from 175 to 40 deg. C. The mono-grade oils produce superior heat transfer characteristics compared to those produced by multi-grade oils. The oil with the best additive concentrations produces boiling heat fluxes up to 4.44 times higher than those produced by some other oils. Comparing the results of the tested oils revealed that the oil that has the largest concentrations of boron, magnesium, phosphorus and zinc with low concentration of calcium yields the best heat transport characteristics among the other tested oils. These additives provide superior detergent and dispersant characteristics, reflected in the large alkalinity and low corrosivity of the oil. On the other side, calcium has a negative interaction with other additives and yields an adverse effect on heat transfer characteristics even when it exists in oil with large concentrations of boron, magnesium, phosphorus and zinc
Maximum Power Output of Quantum Heat Engine with Energy Bath
Directory of Open Access Journals (Sweden)
Shengnan Liu
2016-05-01
Full Text Available The difference between quantum isoenergetic process and quantum isothermal process comes from the violation of the law of equipartition of energy in the quantum regime. To reveal an important physical meaning of this fact, here we study a special type of quantum heat engine consisting of three processes: isoenergetic, isothermal and adiabatic processes. Therefore, this engine works between the energy and heat baths. Combining two engines of this kind, it is possible to realize the quantum Carnot engine. Furthermore, considering finite velocity of change of the potential shape, here an infinite square well with moving walls, the power output of the engine is discussed. It is found that the efficiency and power output are both closely dependent on the initial and final states of the quantum isothermal process. The performance of the engine cycle is shown to be optimized by control of the occupation probability of the ground state, which is determined by the temperature and the potential width. The relation between the efficiency and power output is also discussed.
Shestakov, Igor; Dolgova, Anastasia; Maksimov, Vyacheslav Ivanovich
2015-01-01
The article shows the results of mathematical modeling of convective heat transfer in the low-temperature storage of liquefied natural gas. Regime of natural convection in an enclosure with different intensity of the heat flux at the external borders are investigated. Was examined two-dimensional nonstationary problem within the model of Navier-Stokes in dimensionless variables “vorticity - stream function - temperature”. Distributions of hydrodynamic parameters and temperatures that characte...
Olund, Jeanine K.
2012-01-01
Although the number of women entering science, technology, engineering, and mathematics (STEM) disciplines has increased in recent years, overall there are still more men than women completing four-year degrees in these fields, especially in physics, engineering, and computer science. At higher levels of education and within the workplace, the…
Snead-McDaniel, Kimberly
2010-01-01
An expanding ethnicity gap exists in the number of students pursuing science, technology, engineering, and mathematics (STEM) careers in the United States. The National Action Council for Minorities in Engineering revealed that the number of minorities pursuing STEM degrees and careers has declined over the past few years. The specific origins of…
McDonald, Harry E.
2010-01-01
The United States ranking among the world in science, technology, engineering, and mathematics (STEM) education is decreasing. To counteract this problem NASA has made it part of its mission to promote STEM education among the nation s youth. Mockups can serve as a great tool when promoting STEM education in America. The Orion Cockpit Working Group has created a new program called Students Shaping America s Next Space Craft (SSANS) to outfit the Medium Fidelity Orion Mockup. SSANS will challenge the students to come up with unique designs to represent the flight design hardware. There are two main types of project packages created by SSANS, those for high school students and those for university students. The high school projects will challenge wood shop, metal shop and pre-engineering classes. The university projects are created mainly for senior design projects and will require the students to perform finite element analysis. These projects will also challenge the undergraduate students in material selection and safety requirements. The SSANS program will help NASA in its mission to promote STEM education, and will help to shape our nations youth into the next generation of STEM leaders.
An Engineering Aerodynamic Heating Method for Hypersonic Flow
Riley, Christopher J.; DeJarnette, Fred R.
1992-01-01
A capability to calculate surface heating rates has been incorporated in an approximate three-dimensional inviscid technique. Surface streamlines are calculated from the inviscid solution, and the axisymmetric analog is then used along with a set of approximate convective-heating equations to compute the surface heat transfer. The method is applied to blunted axisymmetric and three-dimensional ellipsoidal cones at angle of attack for the laminar flow of a perfect gas. The method is also applicable to turbulent and equilibrium-air conditions. The present technique predicts surface heating rates that compare favorably with experimental (ground-test and flight) data and numerical solutions of the Navier-Stokes (NS) and viscous shock-layer (VSL) equations. The new technique represents a significant improvement over current engineering aerothermal methods with only a modest increase in computational effort.
SrF2 capsule design for heat engine applications
International Nuclear Information System (INIS)
Lester, D.H.
1976-04-01
A number of design changes were considered to improve heat transfer characteristics of the WESF capsule. This capsule was evaluated in a design concept for use as a heat source in a helium-working fluid, Stirling heat engine. Throughout the study a heat block concept was used. The helium was assumed to be at 1200 0 F and 200 atm. The upper temperature limit at the fuel-metal interface was assumed to be 800 0 C because of material compatibility considerations. A 0.6-in. thick outer can was considered since it may be required for impact resistance and high pressure accident environments. The modifications considered were: (1) filling all gaps with helium rather than air, (2) filling gaps with powdered metal, and (3) adding a third can to the existing capsule. Also, enhancement of emissivity on metal surfaces was considered as a possible modification
Hybrid heat recovery - flat plate Stirling engine system
International Nuclear Information System (INIS)
Bogdanizh, A.M.; Budin, R.; Sutlovizh, I.
2000-01-01
In this paper, the possibility of process condensate heat recovery for boiler water preheating as well as for combined heat and power production for chosen process in textile industry has been investigated. The garment industry requires low pressure process steam or hot water for which production expensive fossil fuel should be used. Fuel usage can be reduced by various energy conservation methods. During the process a great quantity of hot condensate or waste hot water is rejected in the sewage system. To reduce heat wastes and improve technological process this condensate could be returned to the boiler for feed water preheating. When 60% condensate is returned to the steam generator about 8 % natural gas is saved. The rest of the condensate should be used for driving low temperature flat plate Stirling motor the advantage of the flat plate Stirling engine is ability to work at low temperatures. This engine produces electrical energy which can put in motion an electrogenerator in the same plant. While Stirling engine can be used electrical power and economical effect could be much greater using such a hybrid system the process waste heat is not only converted into useful work but at the same time thermal pollution is greatly diminished. (Author)
Size dependence of efficiency at maximum power of heat engine
Izumida, Y.; Ito, N.
2013-01-01
We perform a molecular dynamics computer simulation of a heat engine model to study how the engine size difference affects its performance. Upon tactically increasing the size of the model anisotropically, we determine that there exists an optimum size at which the model attains the maximum power for the shortest working period. This optimum size locates between the ballistic heat transport region and the diffusive heat transport one. We also study the size dependence of the efficiency at the maximum power. Interestingly, we find that the efficiency at the maximum power around the optimum size attains a value that has been proposed as a universal upper bound, and it even begins to exceed the bound as the size further increases. We explain this behavior of the efficiency at maximum power by using a linear response theory for the heat engine operating under a finite working period, which naturally extends the low-dissipation Carnot cycle model [M. Esposito, R. Kawai, K. Lindenberg, C. Van den Broeck, Phys. Rev. Lett. 105, 150603 (2010)]. The theory also shows that the efficiency at the maximum power under an extreme condition may reach the Carnot efficiency in principle.© EDP Sciences Società Italiana di Fisica Springer-Verlag 2013.
Size dependence of efficiency at maximum power of heat engine
Izumida, Y.
2013-10-01
We perform a molecular dynamics computer simulation of a heat engine model to study how the engine size difference affects its performance. Upon tactically increasing the size of the model anisotropically, we determine that there exists an optimum size at which the model attains the maximum power for the shortest working period. This optimum size locates between the ballistic heat transport region and the diffusive heat transport one. We also study the size dependence of the efficiency at the maximum power. Interestingly, we find that the efficiency at the maximum power around the optimum size attains a value that has been proposed as a universal upper bound, and it even begins to exceed the bound as the size further increases. We explain this behavior of the efficiency at maximum power by using a linear response theory for the heat engine operating under a finite working period, which naturally extends the low-dissipation Carnot cycle model [M. Esposito, R. Kawai, K. Lindenberg, C. Van den Broeck, Phys. Rev. Lett. 105, 150603 (2010)]. The theory also shows that the efficiency at the maximum power under an extreme condition may reach the Carnot efficiency in principle.© EDP Sciences Società Italiana di Fisica Springer-Verlag 2013.
A novel heat engine for magnetizing superconductors
Energy Technology Data Exchange (ETDEWEB)
Coombs, T A; Hong, Z; Zhu, X [Cambridge University Engineering Department, Trumpington Street, CB2 1PZ (United Kingdom); Krabbes, G [IFW Dresden, Helmholtzstrasse 20, 01069 Dresden (Germany)
2008-03-01
The potential of bulk melt-processed YBCO single domains to trap significant magnetic fields (Tomita and Murakami 2003 Nature 421 517-20; Fuchs et al 2000 Appl. Phys. Lett. 76 2107-9) at cryogenic temperatures makes them particularly attractive for a variety of engineering applications including superconducting magnets, magnetic bearings and motors (Coombs et al 1999 IEEE Trans. Appl. Supercond. 9 968-71; Coombs et al 2005 IEEE Trans. Appl. Supercond. 15 2312-5). It has already been shown that large fields can be obtained in single domain samples at 77 K. A range of possible applications exist in the design of high power density electric motors (Jiang et al 2006 Supercond. Sci. Technol. 19 1164-8). Before such devices can be created a major problem needs to be overcome. Even though all of these devices use a superconductor in the role of a permanent magnet and even though the superconductor can trap potentially huge magnetic fields (greater than 10 T) the problem is how to induce the magnetic fields. There are four possible known methods: (1) cooling in field; (2) zero field cooling, followed by slowly applied field; (3) pulse magnetization; (4) flux pumping. Any of these methods could be used to magnetize the superconductor and this may be done either in situ or ex situ. Ideally the superconductors are magnetized in situ. There are several reasons for this: first, if the superconductors should become demagnetized through (i) flux creep, (ii) repeatedly applied perpendicular fields (Vanderbemden et al 2007 Phys. Rev. B 75 (17)) or (iii) by loss of cooling then they may be re-magnetized without the need to disassemble the machine; secondly, there are difficulties with handling very strongly magnetized material at cryogenic temperatures when assembling the machine; thirdly, ex situ methods would require the machine to be assembled both cold and pre-magnetized and would offer significant design difficulties. Until room temperature superconductors can be prepared, the
A novel heat engine for magnetizing superconductors
International Nuclear Information System (INIS)
Coombs, T A; Hong, Z; Zhu, X; Krabbes, G
2008-01-01
The potential of bulk melt-processed YBCO single domains to trap significant magnetic fields (Tomita and Murakami 2003 Nature 421 517-20; Fuchs et al 2000 Appl. Phys. Lett. 76 2107-9) at cryogenic temperatures makes them particularly attractive for a variety of engineering applications including superconducting magnets, magnetic bearings and motors (Coombs et al 1999 IEEE Trans. Appl. Supercond. 9 968-71; Coombs et al 2005 IEEE Trans. Appl. Supercond. 15 2312-5). It has already been shown that large fields can be obtained in single domain samples at 77 K. A range of possible applications exist in the design of high power density electric motors (Jiang et al 2006 Supercond. Sci. Technol. 19 1164-8). Before such devices can be created a major problem needs to be overcome. Even though all of these devices use a superconductor in the role of a permanent magnet and even though the superconductor can trap potentially huge magnetic fields (greater than 10 T) the problem is how to induce the magnetic fields. There are four possible known methods: (1) cooling in field; (2) zero field cooling, followed by slowly applied field; (3) pulse magnetization; (4) flux pumping. Any of these methods could be used to magnetize the superconductor and this may be done either in situ or ex situ. Ideally the superconductors are magnetized in situ. There are several reasons for this: first, if the superconductors should become demagnetized through (i) flux creep, (ii) repeatedly applied perpendicular fields (Vanderbemden et al 2007 Phys. Rev. B 75 (17)) or (iii) by loss of cooling then they may be re-magnetized without the need to disassemble the machine; secondly, there are difficulties with handling very strongly magnetized material at cryogenic temperatures when assembling the machine; thirdly, ex situ methods would require the machine to be assembled both cold and pre-magnetized and would offer significant design difficulties. Until room temperature superconductors can be prepared, the
A heating system for piglets in farrowing house using waste heat from biogas engine
Directory of Open Access Journals (Sweden)
Payungsak Junyusen
2008-12-01
Full Text Available The aim of this study is to design and test a heating system for piglets in farrowing house by utilising the waste heat from a biogas engine as a heat source. The study was separated into three parts: the study on the biogas combined heat and power plant, the investigation on the properties of the heat panel, and the installation and testing of the heating system. From the experiment, the condition producing 60 kW of electrical power was a proper one, in which electrical efficiency and specific fuel consumption were 14% and 1.22 m3/kWh respectively. Generating both electricity and heat increased the overall efficiency to 37.7% and decreased the specific fuel consumption to 0.45 m3/kWh. The heat panel, which was made of a plastic material, had a thermal conductivity of 0.58 W/mC and the maximum compressive force and operating pressure of 8.1 kN and 0.35 bar respectively. The surface temperature of the panel was dependent on the inlet water temperature. When hot water of 44C was supplied into the farrowing house with room temperature of 26C, the average surface temperature was 33C. The developed heating system could provide heat for 4.3 farrowing houses. The payback period of this project was 2.5 years.
Irreversible performance of a quantum harmonic heat engine
Rezek, Yair; Kosloff, Ronnie
2006-05-01
The unavoidable irreversible loss of power in a heat engine is found to be of quantum origin. Following thermodynamic tradition, a model quantum heat engine operating in an Otto cycle is analysed, where the working medium is composed of an ensemble of harmonic oscillators and changes in volume correspond to changes in the curvature of the potential well. Equations of motion for quantum observables are derived for the complete cycle of operation. These observables are sufficient to determine the state of the system and with it all thermodynamical variables. Once the external controls are set, the engine settles to a limit cycle. Conditions for optimal work, power and entropy production are derived. At high temperatures and quasistatic operating conditions, the efficiency at maximum power coincides with the endoreversible result \\eta_q=1-\\sqrt{{T_c}/{T_h}} . The optimal compression ratio varies from {\\cal C} =\\sqrt{T_h/T_c} in the quasistatic limit where the irreversibility is dominated by heat conductance to {\\cal C} =(T_h/T_c)^{1/4} in the sudden limit when the irreversibility is dominated by friction. When the engine deviates from adiabatic conditions, the performance is subject to friction. The origin of this friction can be traced to the noncommutability of the kinetic and potential energy of the working medium.
Improving Engine Oil Warm Up through Waste Heat Recovery
Directory of Open Access Journals (Sweden)
Davide Di Battista
2017-12-01
Full Text Available In the transportation sector, engine oil thermal management has not yet received the attention it deserves in the path towards carbon dioxide and pollutants reduction. During the homologation cycle (which represents a typical daily trip, oil temperature reaches its thermal steady value, which insures best performances in terms of viscosity, only in the final part of the trip, when most part of the harmful emissions have been already emitted; therefore, a warm up acceleration would surely represent a strong beneficial action. In this paper, a faster warming up of the lubricant oil was done using the heat owned by the exhaust gases, which was almost immediately ready after the engine ignition, in the early part of a driving cycle. An experimental activity has been developed in a turbocharged engine (F1C 3L IVECO, modifying the oil circuit in order to heat up the oil during the cold phase of a homologation cycle by the exhaust gases. A significant reduction of fuel consumption and pollutant emissions savings has been experimentally demonstrated. Also, the interaction between the modified oil circuit, engine, coolant circuit, and exhaust line has been investigated in order to have a system view of the new heating oil technology.
Barclay, C J
2015-09-01
Contracting muscles produce heat which largely arises from the biochemical reactions that provide the energy for contraction. Measurements of muscle heat production have made, and continue to make, important contributions to our understanding of the bases of contraction. Most measurements of muscle heat production are made using a thermopile, consisting of a series of thermocouples arranged so that alternate thermocouples are in thermal contact with the muscle and with an isothermal reference. In this study, a mathematical model was constructed of a muscle lying on a thermopile consisting of antimony-bismuth thermocouples sandwiched between polymer sheets. The validity of the model was demonstrated by its ability to accurately predict thermopile outputs in response to applying heat to the thermopile surface, to generating heat in the thermocouples using the Peltier effect and to adding heat capacity on the thermopile surface. The model was then used to show how practical changes to thermopile construction could minimise response time and thermopile heat capacity and allow measurement of very low rates of heat production. The impulse response of a muscle-thermopile system was generated using the model and used to illustrate how a measured signal can be deconvolved with the impulse response to correct for lag introduced by the thermopile.
Performance of discrete heat engines and heat pumps in finite time
Feldmann; Kosloff
2000-05-01
The performance in finite time of a discrete heat engine with internal friction is analyzed. The working fluid of the engine is composed of an ensemble of noninteracting two level systems. External work is applied by changing the external field and thus the internal energy levels. The friction induces a minimal cycle time. The power output of the engine is optimized with respect to time allocation between the contact time with the hot and cold baths as well as the adiabats. The engine's performance is also optimized with respect to the external fields. By reversing the cycle of operation a heat pump is constructed. The performance of the engine as a heat pump is also optimized. By varying the time allocation between the adiabats and the contact time with the reservoir a universal behavior can be identified. The optimal performance of the engine when the cold bath is approaching absolute zero is studied. It is found that the optimal cooling rate converges linearly to zero when the temperature approaches absolute zero.
Thermoelectric properties of an interacting quantum dot based heat engine
Erdman, Paolo Andrea; Mazza, Francesco; Bosisio, Riccardo; Benenti, Giuliano; Fazio, Rosario; Taddei, Fabio
2017-06-01
We study the thermoelectric properties and heat-to-work conversion performance of an interacting, multilevel quantum dot (QD) weakly coupled to electronic reservoirs. We focus on the sequential tunneling regime. The dynamics of the charge in the QD is studied by means of master equations for the probabilities of occupation. From here we compute the charge and heat currents in the linear response regime. Assuming a generic multiterminal setup, and for low temperatures (quantum limit), we obtain analytical expressions for the transport coefficients which account for the interplay between interactions (charging energy) and level quantization. In the case of systems with two and three terminals we derive formulas for the power factor Q and the figure of merit Z T for a QD-based heat engine, identifying optimal working conditions which maximize output power and efficiency of heat-to-work conversion. Beyond the linear response we concentrate on the two-terminal setup. We first study the thermoelectric nonlinear coefficients assessing the consequences of large temperature and voltage biases, focusing on the breakdown of the Onsager reciprocal relation between thermopower and Peltier coefficient. We then investigate the conditions which optimize the performance of a heat engine, finding that in the quantum limit output power and efficiency at maximum power can almost be simultaneously maximized by choosing appropriate values of electrochemical potential and bias voltage. At last we study how energy level degeneracy can increase the output power.
Energy Management of a Hybrid-Power Gas Engine-Driven Heat Pump
Directory of Open Access Journals (Sweden)
Qingkun Meng
2015-10-01
Full Text Available The hybrid-power gas engine-driven heat pump (HPGHP combines hybrid power technology with a gas engine heat pump. The engine in the power system is capable of operating constantly with high thermal efficiency and low emissions during different operating modes. In this paper, the mathematical models of various components is established, including the engine thermal efficiency map and the motor efficiency map. The comprehensive charging/discharging efficiency model and energy management optimization strategy model which is proposed to maximize the efficiency of instantaneous HPGHP system are established. Then, different charging/discharging torque limits are obtained. Finally, a novel gas engine economical zone control strategy which combined with the SOC of battery in real time is put forward. The main operating parameters of HPGHP system under energy management are simulated by Matlab/Simulink and validated by experimental data, such as engine and motor operating torque, fuel consumption rate and comprehensive efficiency, etc. The results show that during 3600 s’ run-time, the SOC value of battery packs varies between 0.58 and 0.705, the fuel consumption rate reaches minimum values of approximately 291.3 g/(kW h when the compressor speed is nearly 1550 rpm in mode D, the engine thermal efficiency and comprehensive efficiency reach maximum values of approximately 0.2727 and 0.2648 when the compressor speed is 1575 rpm and 1475 rpm, respectively, in mode D. In general, the motor efficiency can be maintained above 0.85 in either mode.
Mathematical and statistical applications in life sciences and engineering
Adhikari, Mahima; Chaubey, Yogendra
2017-01-01
The book includes articles from eminent international scientists discussing a wide spectrum of topics of current importance in mathematics and statistics and their applications. It presents state-of-the-art material along with a clear and detailed review of the relevant topics and issues concerned. The topics discussed include message transmission, colouring problem, control of stochastic structures and information dynamics, image denoising, life testing and reliability, survival and frailty models, analysis of drought periods, prediction of genomic profiles, competing risks, environmental applications and chronic disease control. It is a valuable resource for researchers and practitioners in the relevant areas of mathematics and statistics.
Heat transfers through diesel-engine cylinder liners
Energy Technology Data Exchange (ETDEWEB)
Green, R T; Jambunathan, K; Probert, S D
1983-01-01
A computer package has been developed, using a finite-element technique, to predict the steady-state rate of heat transfer radially through the cylinder liner, or other axisymmetric components, of a medium-speed diesel engine. Comparisons between experimentally measured and computer predicted results have been made: better corroboration occurs for engine loads above 1034 k N m/sup -2/ BMEP. The predictive computer package DIESHT needs only a simple 'user input' and produces a complete graphical output of generated mesh and computed isotherms. Computational storage requirements are modest so that the program can be used with a CAD system, if required, in order to facilitate an interactive design procedure.
Modern thermodynamics from heat engines to dissipative structures
Kondepudi, Dilip
2014-01-01
Modern Thermodynamics: From Heat Engines to Dissipative Structures, Second Edition presents a comprehensive introduction to 20th century thermodynamics that can be applied to both equilibrium and non-equilibrium systems, unifying what was traditionally divided into 'thermodynamics' and 'kinetics' into one theory of irreversible processes. This comprehensive text, suitable for introductory as well as advanced courses on thermodynamics, has been widely used by chemists, physicists, engineers and geologists. Fully revised and expanded, this new edition includes the following updates and featur
Trajectories of Mathematics and Technology Education Pointing to Engineering Design
Daugherty, Jenny L.; Reese, George C.; Merrill, Chris
2010-01-01
A brief examination and comparison of mathematics and technology education provides the background for a discussion of integration. In particular, members of each field have responded to the increasing pressures to better prepare students for the technologically rich, globally competitive future. Approaches based within each discipline are varied…
Mathematical modeling of heat transfer in production premises heated by gas infrared emitters
Directory of Open Access Journals (Sweden)
Maksimov Vyacheslav I.
2017-01-01
Full Text Available The results of numerical modeling of the process of free convective heat transfer in the regime of turbulent convection in a closed rectangular region heated by an infrared radiator are presented. The system of Navier-Stokes equations in the Boussinesq approximation is solved, the energy equation for the gas and the heat conduction equations for the enclosing vertical and horizontal walls. A comparative analysis of the heat transfer regimes in the considered region for different Grashof numbers is carried out. The features of the formation of heated air flows relative to the infrared emitter located at some distance from the upper horizontal boundary of the region are singled out.
Alves, Manuela; Rodrigues, Cristina S.; Rocha, Ana Maria A. C.; Coutinho, Clara
2016-01-01
The accomplishment in mathematics has gained attention from educators and arises as an emerging field of study, including in engineering education. However, in Portugal, there is still incipient research in the area; so it is high time to explore factors that might enlighten the gap in the study of the relationship between Portuguese engineering students and the learning of mathematics. The main purpose of this study is to explore three factors identified in the literature as influencing the learning of mathematical concepts - self-efficacy, anxiety towards mathematics and perceived importance of mathematics - and search for differences by gender and by type of engineering course, a dimension not much reported in the literature but which was revealed as important in the team's previous research. Based on a sample of 140 undergraduate students of different engineering courses from University of Minho, results only identify differences in the type of course and not in gender. These results constitute a contribution and open new paths for future research in the engineering education.
Recovery of Exhaust Waste Heat for ICE Using the Beta Type Stirling Engine
Aladayleh, Wail; Alahmer, Ali
2015-01-01
This paper investigates the potential of utilizing the exhaust waste heat using an integrated mechanical device with internal combustion engine for the automobiles to increase the fuel economy, the useful power, and the environment safety. One of the ways of utilizing waste heat is to use a Stirling engine. A Stirling engine requires only an external heat source as wasted heat for its operation. Because the exhaust gas temperature may reach 200 to 700°C, Stirling engine will work effectively....
On introduction of artificial intelligence elements to heat power engineering
Dregalin, A. F.; Nazyrova, R. R.
1993-10-01
The basic problems of 'the thermodynamic intelligence' of personal computers have been outlined. The thermodynamic intellect of personal computers as a concept has been introduced to heat processes occurring in engines of flying vehicles. In particular, the thermodynamic intellect of computers is determined by the possibility of deriving formal relationships between thermodynamic functions. In chemical thermodynamics, a concept of a characteristic function has been introduced.
Gold, Zachary Samuel
Engineering play is a new perspective on preschool education that views constructive play as an engineering design process that parallels the way engineers think and work when they develop engineered solutions to human problems (Bairaktarova, Evangelou, Bagiati, & Brophy, 2011). Early research from this perspective supports its use in framing play as a key learning context. However, no research to date has examined associations between engineering play and other factors linked with early school success, such as executive function, mathematical ability, and spatial ability. Additionally, more research is needed to further validate a new engineering play observational measure. This study had two main goals: (1) to gather early validity data on the engineering play measure as a potentially useful instrument for documenting the occurrence of children's engineering play behaviors in educational contexts, such as block play. This was done by testing the factor structure of the engineering play behaviors in this sample and their association with preschoolers' planning, a key aspect of the engineering design process; (2) to explore associations between preschoolers' engineering play and executive function, mathematical ability, and spatial ability. Participants included 110 preschoolers (62 girls; 48 boys; M = 58.47 months) from 10 classrooms in the Midwest United States coded for their frequency of engagement in each of the nine engineering play behaviors. A confirmatory factor analysis resulted in one engineering play factor including six of the engineering play behaviors. A series of marginal regression models revealed that the engineering play factor was significantly and positively associated with the spatial horizontal rotation transformation. However, engineering play was not significantly related to planning ability, executive function, informal mathematical abilities, or other spatial transformation skills. Follow-up analyses revealed significant positive
Investigating and developing engineering students' mathematical modelling and problem-solving skills
Wedelin, Dag; Adawi, Tom; Jahan, Tabassum; Andersson, Sven
2015-09-01
How do engineering students approach mathematical modelling problems and how can they learn to deal with such problems? In the context of a course in mathematical modelling and problem solving, and using a qualitative case study approach, we found that the students had little prior experience of mathematical modelling. They were also inexperienced problem solvers, unaware of the importance of understanding the problem and exploring alternatives, and impeded by inappropriate beliefs, attitudes and expectations. Important impacts of the course belong to the metacognitive domain. The nature of the problems, the supervision and the follow-up lectures were emphasised as contributing to the impacts of the course, where students show major development. We discuss these empirical results in relation to a framework for mathematical thinking and the notion of cognitive apprenticeship. Based on the results, we argue that this kind of teaching should be considered in the education of all engineers.
Directory of Open Access Journals (Sweden)
Maxim Glushenkov
2018-01-01
Full Text Available Isobaric expansion (IE engines are a very uncommon type of heat-to-mechanical-power converters, radically different from all well-known heat engines. Useful work is extracted during an isobaric expansion process, i.e., without a polytropic gas/vapour expansion accompanied by a pressure decrease typical of state-of-the-art piston engines, turbines, etc. This distinctive feature permits isobaric expansion machines to serve as very simple and inexpensive heat-driven pumps and compressors as well as heat-to-shaft-power converters with desired speed/torque. Commercial application of such machines, however, is scarce, mainly due to a low efficiency. This article aims to revive the long-known concept by proposing important modifications to make IE machines competitive and cost-effective alternatives to state-of-the-art heat conversion technologies. Experimental and theoretical results supporting the isobaric expansion technology are presented and promising potential applications, including emerging power generation methods, are discussed. It is shown that dense working fluids with high thermal expansion at high process temperature and low compressibility at low temperature make it possible to operate with reasonable thermal efficiencies at ultra-low heat source temperatures (70–100 °C. Regeneration/recuperation of heat can increase the efficiency notably and extend the area of application of these machines to higher heat source temperatures. For heat source temperatures of 200–600 °C, the efficiency of these machines can reach 20–50% thus making them a flexible, economical and energy efficient alternative to many today’s power generation technologies, first of all organic Rankine cycle (ORC.
Mathematics Education for Engineering Technology Students – A Bridge Too Far?
Directory of Open Access Journals (Sweden)
Noraishiyah Abdullah
2013-03-01
Full Text Available Trying to decide what is best suited for someone or something is an ever enduring task let alone trying to prepare students with the right engineering mind. So ‘how do you build an engineer?’ if that is the right word. What is the right ingredient? Mathematics has been said as the most important foundation in engineers’ life. Curriculum has been developed and reviewed over the years to meet this target. This work explores how much or lack of it has the curriculum prepares the future technologist to face the world of engineering technology as far as mathematics is concerned. Analysis of mathematics lectures, interviews of engineering technologist students and engineering technology subject lecturer is undertaken. Understand what each contributes help in understanding the picture that the current education is painting. Based on the theory of learning, APOS theory helps in explaining how students bridge their knowledge of mathematics when it comes to solving engineering technology problems. The question is, is it a bridge too far?
The Gender-Equality Paradox in Science, Technology, Engineering, and Mathematics Education.
Stoet, G; Geary, DC
2018-01-01
The underrepresentation of girls and women in science, technology, engineering, and mathematics (STEM) fields is a continual concern for social scientists and policymakers. Using an international database on adolescent achievement in science, mathematics, and reading ( N = 472,242), we showed that girls performed similarly to or better than boys in science in two of every three countries, and in nearly all countries, more girls appeared capable of college-level STEM study than had enrolled. P...
A quantum Szilard engine without heat from a thermal reservoir
Hamed Mohammady, M.; Anders, Janet
2017-11-01
We study a quantum Szilard engine that is not powered by heat drawn from a thermal reservoir, but rather by projective measurements. The engine is constituted of a system { S }, a weight { W }, and a Maxwell demon { D }, and extracts work via measurement-assisted feedback control. By imposing natural constraints on the measurement and feedback processes, such as energy conservation and leaving the memory of the demon intact, we show that while the engine can function without heat from a thermal reservoir, it must give up at least one of the following features that are satisfied by a standard Szilard engine: (i) repeatability of measurements; (ii) invariant weight entropy; or (iii) positive work extraction for all measurement outcomes. This result is shown to be a consequence of the Wigner-Araki-Yanase theorem, which imposes restrictions on the observables that can be measured under additive conservation laws. This observation is a first-step towards developing ‘second-law-like’ relations for measurement-assisted feedback control beyond thermality.
Mathematical modelling in engineering: A proposal to introduce linear algebra concepts
Directory of Open Access Journals (Sweden)
Andrea Dorila Cárcamo
2016-03-01
Full Text Available The modern dynamic world requires that basic science courses for engineering, including linear algebra, emphasize the development of mathematical abilities primarily associated with modelling and interpreting, which aren´t limited only to calculus abilities. Considering this, an instructional design was elaborated based on mathematic modelling and emerging heuristic models for the construction of specific linear algebra concepts: span and spanning set. This was applied to first year engineering students. Results suggest that this type of instructional design contributes to the construction of these mathematical concepts and can also favour first year engineering students understanding of key linear algebra concepts and potentiate the development of higher order skills.
Seymour, David C.; Martin, Michael A.; Nguyen, Huy H.; Greene, William D.
2005-01-01
The subject of mathematical modeling of the transient operation of liquid rocket engines is presented in overview form from the perspective of engineers working at the NASA Marshall Space Flight Center. The necessity of creating and utilizing accurate mathematical models as part of liquid rocket engine development process has become well established and is likely to increase in importance in the future. The issues of design considerations for transient operation, development testing, and failure scenario simulation are discussed. An overview of the derivation of the basic governing equations is presented along with a discussion of computational and numerical issues associated with the implementation of these equations in computer codes. Also, work in the field of generating usable fluid property tables is presented along with an overview of efforts to be undertaken in the future to improve the tools use for the mathematical modeling process.
Directory of Open Access Journals (Sweden)
Tan Chan Sin
2015-01-01
Full Text Available Productivity rate (Q or production rate is one of the important indicator criteria for industrial engineer to improve the system and finish good output in production or assembly line. Mathematical and statistical analysis method is required to be applied for productivity rate in industry visual overviews of the failure factors and further improvement within the production line especially for automated flow line since it is complicated. Mathematical model of productivity rate in linear arrangement serial structure automated flow line with different failure rate and bottleneck machining time parameters becomes the basic model for this productivity analysis. This paper presents the engineering mathematical analysis method which is applied in an automotive company which possesses automated flow assembly line in final assembly line to produce motorcycle in Malaysia. DCAS engineering and mathematical analysis method that consists of four stages known as data collection, calculation and comparison, analysis, and sustainable improvement is used to analyze productivity in automated flow assembly line based on particular mathematical model. Variety of failure rate that causes loss of productivity and bottleneck machining time is shown specifically in mathematic figure and presents the sustainable solution for productivity improvement for this final assembly automated flow line.
Directory of Open Access Journals (Sweden)
Zeeshan Nawaz
2009-04-01
Full Text Available The present research focuses to develop mathematical model for the removal of iron (magnetite by ion-exchange resin from primary heat transfer loop of process industries. This mathematical model is based on operating capacities (that’s provide more effective design as compared to loading capacity from static laboratory tests. Results showed non-steady state distribution of external Fe2+ and limitations imposed on operating conditions, these conditions includes; loading and elution cycle time, flow rate, concentration of both loading and removal, volume of resin required. Number of generalized assumptions was made under shortcut modeling techniques to overcome the gap of theoretical and actual process design.
Directory of Open Access Journals (Sweden)
Natal’ya Yur’evna Gorbunova
2017-06-01
Full Text Available We described several aspects of organizing student research work, as well as solving a number of mathematical modeling problems: professionally-oriented, multi-stage, etc. We underlined the importance of their economic content. Samples of using such problems in teaching Mathematics at agricultural university were given. Several questions connected with information material selection and peculiarities of research problems application were described. Purpose. The author aims to show the possibility and necessity of using professionally-oriented problems of mathematical modeling in teaching Mathematics at agricultural university. The subject of analysis is including such problems into educational process. Methodology. The main research method is dialectical method of obtaining knowledge of finding approaches to selection, writing and using mathematical modeling and professionally-oriented problems in educational process; the methodology is study of these methods of obtaining knowledge. Results. As a result of analysis of literature, students opinions, observation of students work, and taking into account personal teaching experience, it is possible to make conclusion about importance of using mathematical modeling problems, as it helps to systemize theoretical knowledge, apply it to practice, raise students study motivation in engineering sphere. Practical implications. Results of the research can be of interest for teachers of Mathematics in preparing Bachelor and Master students of engineering departments of agricultural university both for theoretical research and for modernization of study courses.
International Nuclear Information System (INIS)
Yassin, Jamal S.; Eljrushi, Gibril S.
2006-01-01
This paper presents a mathematical model for thermal desalination plant operating with solar energy and hydrogen. This plant is composed of two main systems, the heating system and the distillation system. The distillation system is composed of multi-cells; each cell is using the humidification-dehumidification (H-D) process in the distillation unit and getting the required amount of heat from feed seawater heater. The feed seawater heater is a heat exchanger used to raise the temperature of the preheated seawater coming from the condensation chamber (Dehumidifier) of each cell to about 85 degree centigrade. The heating amount in the heat exchangers is obtained from the thermal storage tank, which gets its energy from solar thermal system and is coupled with a hydrogen-fired backup system to guaranty necessary operating conditions and permit 24 hours solar H-D desalination plant to enhance the performance of this system. The mathematical model studies the performance of the proposed desalination system using thermal solar energy and hydrogen as fuel. Other pertinent variable in the heating and distillation system are also studied. The outcomes of this study are analyzed to enhance the used solar desalination process and make commercial.(Author)
Osmotic heat engine using thermally responsive ionic liquids
Zhong, Yujiang
2017-07-11
The osmotic heat engine (OHE) is a promising technology for converting low grade heat to electricity. Most of the existing studies have focused on thermolytic salt systems. Herein, for the first time, we proposed to use thermally responsive ionic liquids (TRIL) that have either an upper critical solution temperature (UCST) or lower critical solution temperature (LCST) type of phase behavior as novel thermolytic osmotic agents. Closed-loop TRIL-OHEs were designed based on these unique phase behaviors to convert low grade heat to work or electricity. Experimental studies using two UCST-type TRILs, protonated betaine bis(trifluoromethyl sulfonyl)imide ([Hbet][Tf2N]) and choline bis(trifluoromethylsulfonyl)imide ([Choline][Tf2N]) showed that (1) the specific energy of the TRIL-OHE system could reach as high as 4.0 times that of the seawater and river water system, (2) the power density measured from a commercial FO membrane reached up to 2.3 W/m2, and (3) the overall energy efficiency reached up to 2.6% or 18% of the Carnot efficiency at no heat recovery and up to 10.5% or 71% of the Carnet efficiency at 70% heat recovery. All of these results clearly demonstrated the great potential of using TRILs as novel osmotic agents to design high efficient OHEs for recovery of low grade thermal energy to work or electricity.
Engine and radiator: fetal and placental interactions for heat dissipation.
Schröder, H J; Power, G G
1997-03-01
The 'engine' of fetal metabolism generates heat (3-4 W kg-1 in fetal sheep) which has to be dissipated to the maternal organism. Fetal heat may move through the amniotic/allantoic fluids to the uterine wall (conductive pathway; total conductance, 1.1 W degrees C-1 kg-1) and with the umbilical arterial blood flow (convective pathway) to the placenta. Because resistance to heat flow is larger than zero fetal temperature exceeds maternal temperature by about 0.5 degree C (0.3-1 degree C). Probably 85% of fetal heat is lost to the maternal organism through the placenta, which thus serves as the main 'radiator'. Placental heat conductivity appears to be extremely high and this may lead to impaired heat exchange (guinea-pig placenta). A computer simulation demonstrates that fetal temperature is essentially clamped to maternal temperature, and that fetal thermoregulatory efforts to gain thermal independence would be futile. Indeed, when the late gestational fetus in utero is challenged by cold stress, direct and indirect indicators of (non-shivering) thermogenesis (oxygen consumption, increase of plasma glycerol and free fatty acid levels) change only moderately. In prematurely delivered lambs, however, cold stress provokes summit metabolism and maximum heat production. Only when birth is imitated in utero (by cord clamping, external artificial lung ventilation and cooling) do thermogenic efforts approach levels typical of extra-uterine life. This suggests the presence of inhibitors of thermogenesis of placental origin, e.g. prostaglandins and adenosine. When the synthesis of prostaglandins is blocked by pretreatment with indomethacin, sheep fetuses react to intra-uterine cooling with vigorous thermogenic responses, which can be subdued by infusion of prostaglandin E2 (PGE2). Since the sheep placenta is known to produce sufficient amounts of PGE2, it seems that the placenta controls fetal thermogenic responses to some extent. This transforms the fetus into an ectothermic
Performance characteristics of a combination solar photovoltaic heat engine energy converter
Chubb, Donald L.
1987-01-01
A combination solar photovoltaic heat engine converter is proposed. Such a system is suitable for either terrestrial or space power applications. The combination system has a higher efficiency than either the photovoltaic array or the heat engine alone can attain. Advantages in concentrator and radiator area and receiver mass of the photovoltaic heat engine system over a heat-engine-only system are estimated. A mass and area comparison between the proposed space station organic Rankine power system and a combination PV-heat engine system is made. The critical problem for the proposed converter is the necessity for high temperature photovoltaic array operation. Estimates of the required photovoltaic temperature are presented.
Sliding seal materials for low heat rejection engines
Beaty, Kevin; Lankford, James; Vinyard, Shannon
1989-01-01
Sliding friction coefficients and wear rates of promising piston seal materials were measured under temperature, environmental, velocity, and loading conditions that are representative of the low heat rejection (LHR) diesel engine environment. These materials included carbides, oxides, and nitrides. In addition, silicon nitride and partially stablized zirconia disks (cylinder liners) were ion-implanted with TiNi, Ni, Co, and Cr, and subsequently run against carbide pins (piston rings), with the objective of producing reduced friction via solid lubrication at elevated temperature. Friction and wear measurements were obtained using pin-on-disk laboratory experiments and a unique engine friction test rig. Unmodified ceramic sliding couples were characterized at all temperatures by friction coefficients of 0.24 and above during the pin-on-disk tests. The coefficient at 800 C in an oxidizing environment was reduced to below 0.1, for certain material combination, by the ion-implantation of TiNi or Co. This beneficial effect was found to derive from the lubricious Ti, Ni, and Co oxides. Similar results were demonstrated on the engine friction test rig at lower temperatures. The structural integrity and feasibility of engine application with the most promising material combination were demonstrated during a 30-hour single-cylinder, direct-injection diesel engine test.
The High Level Mathematical Models in Calculating Aircraft Gas Turbine Engine Parameters
Directory of Open Access Journals (Sweden)
Yu. A. Ezrokhi
2017-01-01
Full Text Available The article describes high-level mathematical models developed to solve special problems arising at later stages of design with regard to calculation of the aircraft gas turbine engine (GTE under real operating conditions. The use of blade row mathematics models, as well as mathematical models of a higher level, including 2D and 3D description of the working process in the engine units and components, makes it possible to determine parameters and characteristics of the aircraft engine under conditions significantly different from the calculated ones.The paper considers application of mathematical modelling methods (MMM for solving a wide range of practical problems, such as forcing the engine by injection of water into the flowing part, estimate of the thermal instability effect on the GTE characteristics, simulation of engine start-up and windmill starting condition, etc. It shows that the MMM use, when optimizing the laws of the compressor stator control, as well as supplying cooling air to the hot turbine components in the motor system, can significantly improve the integral traction and economic characteristics of the engine in terms of its gas-dynamic stability, reliability and resource.It ought to bear in mind that blade row mathematical models of the engine are designed to solve purely "motor" problems and do not replace the existing models of various complexity levels used in calculation and design of compressors and turbines, because in “quality” a description of the working processes in these units is inevitably inferior to such specialized models.It is shown that the choice of the mathematical modelling level of an aircraft engine for solving a particular problem arising in its designing and computational study is to a large extent a compromise problem. Despite the significantly higher "resolution" and information ability the motor mathematical models containing 2D and 3D approaches to the calculation of flow in blade machine
Strengthening programs in science, engineering and mathematics. Third annual progress report
Energy Technology Data Exchange (ETDEWEB)
Sandhu, S.S.
1997-09-30
The Division of Natural Sciences and Mathematics at Claflin College consists of the Departments of Biology, Chemistry, Computer Science, Physics, Engineering and Mathematics. It offers a variety of major and minor academic programs designed to meet the mission and objectives of the college. The division`s pursuit to achieve excellence in science education is adversely impacted by the poor academic preparation of entering students and the lack of equipment, facilities and research participation, required to impart adequate academic training and laboratory skills to the students. Funds were received from the US Department of Energy to improve the divisional facilities and laboratory equipment and establish mechanism at pre-college and college levels to increase (1) the pool of high school students who will enroll in Science and Mathematics courses (2) the pool of well qualified college freshmen who will seek careers in Science, Engineering and Mathematics (3) the graduation rate in Science,engineering and Mathematics at the undergraduate level and (4) the pool of well-qualified students who can successfully compete to enter the graduate schools of their choice in the fields of science, engineering, and mathematics. The strategies that were used to achieve the mentioned objectives include: (1) Improved Mentoring and Advisement, (2) Summer Science Camp for 7th and 8th graders, (3) Summer Research Internships for Claflin SEM Seniors, (4) Summer Internships for Rising High School Seniors, (5) Development of Mathematical Skills at Pre-college/Post-secondary Levels, (6) Expansion of Undergraduate Seminars, (7) Exposure of Undergraduates to Guest Speakers/Roll Models, (8) Visitations by Undergraduate Students to Graduate Schools, and (9) Expanded Academic Program in Environmental Chemistry.
A comparative study of open and closed heat-engines for small-scale CHP applications
Eames, Ian W.; Evans, Kieran; Pickering, Stephen
2016-01-01
In this paper the authors compare and contrast open and closed-cycle heat engines. First of all, by way of example and to aid discussion, the performance of proprietary externally heated closed-cycle Stirling engines is compared with that of internally heated open Otto cycle engines. Both types of engine have disadvantages and merits and this suggested that in order to accommodate the best of both engine types an externally-heated open-cycle engine might offer a more satisfactory solution for...
Why So Few? Women in Science, Technology, Engineering, and Mathematics
Hill, Catherine; Corbett, Christianne; St. Rose, Andresse
2010-01-01
The number of women in science and engineering is growing, yet men continue to outnumber women, especially at the upper levels of these professions. In elementary, middle, and high school, girls and boys take math and science courses in roughly equal numbers, and about as many girls as boys leave high school prepared to pursue science and…
A mathematical model to predict the effect of heat recovery on the wastewater temperature in sewers.
Dürrenmatt, David J; Wanner, Oskar
2014-01-01
Raw wastewater contains considerable amounts of energy that can be recovered by means of a heat pump and a heat exchanger installed in the sewer. The technique is well established, and there are approximately 50 facilities in Switzerland, many of which have been successfully using this technique for years. The planning of new facilities requires predictions of the effect of heat recovery on the wastewater temperature in the sewer because altered wastewater temperatures may cause problems for the biological processes used in wastewater treatment plants and receiving waters. A mathematical model is presented that calculates the discharge in a sewer conduit and the spatial profiles and dynamics of the temperature in the wastewater, sewer headspace, pipe, and surrounding soil. The model was implemented in the simulation program TEMPEST and was used to evaluate measured time series of discharge and temperatures. It was found that the model adequately reproduces the measured data and that the temperature and thermal conductivity of the soil and the distance between the sewer pipe and undisturbed soil are the most sensitive model parameters. The temporary storage of heat in the pipe wall and the exchange of heat between wastewater and the pipe wall are the most important processes for heat transfer. The model can be used as a tool to determine the optimal site for heat recovery and the maximal amount of extractable heat. Copyright © 2013 Elsevier Ltd. All rights reserved.
Resource Review: Why So Few? Women in Science, Technology, Engineering, and Mathematics
Patricia A. Dawson
2014-01-01
“Why So Few? Women in Science, Technology, Engineering and Mathematics” (Hill, C., Corbett, C., Rose, A., 2010) reports on an extensive study of women’s underrepresentation in science, technology, engineering, and mathematics professions. Funded by the National Science Foundation, the project was conducted by American Association of University Women. The resource includes findings from eight research studies which examined social and environmental factors which contribute to women’s underrepr...
Mathematical modeling of a four-stroke resonant engine for micro and mesoscale applications
Preetham, B. S.; Anderson, M.; Richards, C.
2014-12-01
In order to mitigate frictional and leakage losses in small scale engines, a compliant engine design is proposed in which the piston in cylinder arrangement is replaced by a flexible cavity. A physics-based nonlinear lumped-parameter model is derived to predict the performance of a prototype engine. The model showed that the engine performance depends on input parameters, such as heat input, heat loss, and load on the engine. A sample simulation for a reference engine with octane fuel/air ratio of 0.043 resulted in an indicated thermal efficiency of 41.2%. For a fixed fuel/air ratio, higher output power is obtained for smaller loads and vice-versa. The heat loss from the engine and the work done on the engine during the intake stroke are found to decrease the indicated thermal efficiency. The ratio of friction work to indicated work in the prototype engine is about 8%, which is smaller in comparison to the traditional reciprocating engines.
A heat mathematical model of polymer composite cylinder during microwave treatment
Directory of Open Access Journals (Sweden)
S. V. Reznik
2014-01-01
Full Text Available Traditional technologies of producing epoxy based polymer composite materials (PCM require a long-term and energy consuming thermal processing. Microwave heating could be used as an alternative technology for heating work pieces made of PCM; this would allow to reduce treatment time and energy consumption significantly. A mathematical model of temperature distribution inside a cylindrical composite system during microwave treatment was investigated in this paper. The model includes a hollow PCM cylinder made of an epoxy binder and carbon fibers and a solid cylindrical mandrel. Theoretical and experimental results on the temperature state of the system were analyzed and discussed.
Directory of Open Access Journals (Sweden)
Mančić Marko V.
2014-01-01
Full Text Available Buildings with indoor swimming pools have a large energy footprint. The source of major energy loss is the swimming pool hall where air humidity is increased by evaporation from the pool water surface. This increases energy consumption for heating and ventilation of the pool hall, fresh water supply loss and heat demand for pool water heating. In this paper, a mathematical model of the swimming pool was made to assess energy demands of an indoor swimming pool building. The mathematical model of the swimming pool is used with the created multi-zone building model in TRNSYS software to determine pool hall energy demand and pool losses. Energy loss for pool water and pool hall heating and ventilation are analyzed for different target pool water and air temperatures. The simulation showed that pool water heating accounts for around 22%, whereas heating and ventilation of the pool hall for around 60% of the total pool hall heat demand. With a change of preset controller air and water temperatures in simulations, evaporation loss was in the range 46-54% of the total pool losses. A solar thermal sanitary hot water system was modelled and simulated to analyze it's potential for energy savings of the presented demand side model. The simulation showed that up to 87% of water heating demands could be met by the solar thermal system, while avoiding stagnation. [Projekat Ministarstva nauke Republike Srbije, br. III 42006: Research and development of energy and environmentally highly effective polygeneration systems based on using renewable energy sources
Energy Technology Data Exchange (ETDEWEB)
Kim, Cheol Min; Chang, Se Dong [HAC R and D Laboratory, LG Electronics, 327-23 Gasan-Dong, Geumcheon-gu, Seoul 153-802 (Korea); Lee, Jaekeun; Hwang, Yujin [School of Mechanical Engineering, Pusan National University, San 30, Changjeon-Dong, Keumjeong-Ku, Busan 609-735 (Korea)
2009-11-15
This paper is concerned with the effect of recovered heat on the heating capacity of an Electric Heat Pump (EHP), which is supplied with electric power and recovered heat from a gas engine generator system. Two methods of supplying recovery heat are examined: (i) to the refrigerant with the discharge line heat exchanger (HEX), and (ii) to the refrigerant of the evaporator with the sub-evaporator. Heating capacity, input power and coefficient of performance (COP) were investigated and compared for each heat recovery method. Conclusively, we found that the second method was most reasonable to recover wasted heat and increased system COP by 215%. (author)
Kinnari-Korpela, Hanna
2015-01-01
Mathematics' skills and knowledge lay the basis for engineering studies. However, the resources targeted to mathematics' teaching are in many cases very limited. During the past years in our university the reduction of mathematics' contact hours has been significant while at the same time the study groups have grown. However, the mathematical…
Mathematical modeling of the heat frozen earth in OpenFOAM
International Nuclear Information System (INIS)
Kudryashov, N.A.; Chmykhov, M.A.; Kartashev, A.P.
2015-01-01
A mathematical model of heating permafrost has been presented with allowance for the Stefan condition at the boundary melting. A numerical algorithm has been proposed for analyzing this process. A computation module has been developed on an open architecture with the use of object-oriented programming language OpenFOAM. The computation module has been verified on the known exact solutions of simplified problems [ru
Engineering design aspects of the heat-pipe power system
International Nuclear Information System (INIS)
Capell, B.M.; Houts, M.G.; Poston, D.I.; Berte, M.
1997-10-01
The Heat-pipe Power System (HPS) is a near-term, low-cost space power system designed at Los Alamos that can provide up to 1,000 kWt for many space nuclear applications. The design of the reactor is simple, modular, and adaptable. The basic design allows for the use of a variety of power conversion systems and reactor materials (including the fuel, clad, and heat pipes). This paper describes a project that was undertaken to develop a database supporting many engineering aspects of the HPS design. The specific tasks discussed in this paper are: the development of an HPS materials database, the creation of finite element models that will allow a wide variety of investigations, and the verification of past calculations
Engineering design aspects of the heat-pipe power system
Capell, B. M.; Houts, M. G.; Poston, D. I.; Berte, M.
1997-01-01
The Heat-pipe Power System (HPS) is a near-term, low-cost space power system designed at Los Alamos that can provide up to 1,000 kWt for many space nuclear applications. The design of the reactor is simple, modular, and adaptable. The basic design allows for the use of a variety of power conversion systems and reactor materials (including the fuel, clad, and heat pipes). This paper describes a project that was undertaken to develop a database supporting many engineering aspects of the HPS design. The specific tasks discussed in this paper are: the development of an HPS materials database, the creation of finite element models that will allow a wide variety of investigations, and the verification of past calculations.
Mathematics for physicists and engineers fundamentals and interactive study guide
Weltner, Klaus; Weber, Wolfgang J; Schuster, Peter; Grosjean, Jean
2014-01-01
This textbook offers an accessible and highly approved approach which is characterized by the combination of the textbook with a detailed study guide available online at our repository extras.springer.com. This study guide divides the whole learning task into small units which the student is very likely to master successfully. Thus he or she is asked to read and study a limited section of the textbook and to return to the study guide afterwards. Working with the study guide his or her learning results are controlled, monitored and deepened by graded questions, exercises, repetitions and finally by problems and applications of the content studied. Since the degree of difficulties is slowly rising the students gain confidence and experience their own progress in mathematical competence thus fostering motivation. Furthermore in case of learning difficulties he or she is given supplementary explanations and in case of individual needs supplementary exercises and applications. So the sequence of the studies is ind...
Convective Heating of the LIFE Engine Target During Injection
Energy Technology Data Exchange (ETDEWEB)
Holdener, D S; Tillack, M S; Wang, X R
2011-10-24
Target survival in the hostile, high temperature xenon environment of the proposed Laser Inertial Fusion Energy (LIFE) engine is critical. This work focuses on the flow properties and convective heat load imposed upon the surface of the indirect drive target while traveling through the xenon gas. While this rarefied flow is traditionally characterized as being within the continuum regime, it is approaching transition where conventional CFD codes reach their bounds of operation. Thus ANSYS, specifically the Navier-Stokes module CFX, will be used in parallel with direct simulation Monte Carlo code DS2V and analytically and empirically derived expressions for heat transfer to the hohlraum for validation. Comparison of the viscous and thermal boundary layers of ANSYS and DS2V were shown to be nearly identical, with the surface heat flux varying less than 8% on average. From the results herein, external baffles have been shown to reduce this heat transfer to the sensitive laser entrance hole (LEH) windows and optimize target survival independent of other reactor parameters.
Decomposition techniques in mathematical programming engineering and science applications
Conejo, Antonio J; Minguez, Roberto; Garcia-Bertrand, Raquel
2006-01-01
Optimization plainly dominates the design, planning, operation, and c- trol of engineering systems. This is a book on optimization that considers particular cases of optimization problems, those with a decomposable str- ture that can be advantageously exploited. Those decomposable optimization problems are ubiquitous in engineering and science applications. The book considers problems with both complicating constraints and complicating va- ables, and analyzes linear and nonlinear problems, with and without in- ger variables. The decomposition techniques analyzed include Dantzig-Wolfe, Benders, Lagrangian relaxation, Augmented Lagrangian decomposition, and others. Heuristic techniques are also considered. Additionally, a comprehensive sensitivity analysis for characterizing the solution of optimization problems is carried out. This material is particularly novel and of high practical interest. This book is built based on many clarifying, illustrative, and compu- tional examples, which facilitate the learning p...
Geometric Calculus -- Engineering Mathematics for the 21st century
HITZER, Eckhard MS
2002-01-01
This paper treats important questions at the interface of mathmatics and the engineering science. It starts off with a quick quotation tour through 2300 years of mathmatical history. At the beginning of the 21 century,technology has developed beyond every expectation. But do we also learn and practice an adequately modern form of mathmatics? The papaer argues that this role is very likely to be played by universal geometric calculus. The fundamental geometric product of vectors is introduced....
Celedón-Pattichis, Sylvia; LópezLeiva, Carlos Alfonso; Pattichis, Marios S.; Llamocca, Daniel
2013-01-01
There is a strong need in the United States to increase the number of students from underrepresented groups who pursue careers in Science, Technology, Engineering, and Mathematics. Drawing from sociocultural theory, we present approaches to establishing collaborations between computer engineering and mathematics/bilingual education faculty to…
DEFF Research Database (Denmark)
Triantafyllou, Evangelia; Misfeldt, Morten; Timcenko, Olga
2015-01-01
In this article, we present our idea of using a game engine (Unity) to teach Media Technology students mathematics-related concepts. In order to observe how the introduction of a technological tool, namely the game engine, changes the practices in mathematical work, we adopted the anthropological...
Stevenson, Heidi J.
2014-01-01
The Business Roundtable (2013) website presents a common narrative in regard to STEM (Science, Technology, Engineering and Mathematics) education, "American students are falling behind in math and science. Fewer and fewer students are pursuing careers in science, technology, engineering and mathematics, and American students are performing at…
2015-08-03
AND SUBTITLE Mobile STEMship Discovery Center: K-12 Aerospace-Based Science, Technology, Engineering, and Mathematics (STEM) Mobile Teaching Vehicle...Center program to be able to expose Science Technology, Engineering and Mathematics (STEM) space-inspired science centers for DC Metro beltway schools
Engineering Physics and Mathematics Division progress report for period ending March 31, 1991
Energy Technology Data Exchange (ETDEWEB)
1991-10-01
The primary purpose of this report is to provide an archival record of the activities of the Engineering Physics and Mathematics Division during the period September 1, 1989 through March 31, 1991. Earlier reports in this series are identified on the previous pages, along with the progress reports describing ORNL's research on the mathematical sciences prior to 1984 when those activities moved into the division. As in previous reports, our research is described through abstracts of journal articles, technical reports, and presentations. Summary lists of publications and presentations, staff additions and departures, scientific and professional activities of division staff, and technical conferences organized and sponsored by the division are included as appendices. The report is organized following the division of our research among four sections and information centers. These research areas are: Mathematical Sciences; Nuclear Data Measurement and Evaluations; Intelligent Systems; Nuclear Analysis and Shielding; and Engineering Physics Information Center.
Engineering Physics and Mathematics Division progress report for period ending September 30, 1987
Energy Technology Data Exchange (ETDEWEB)
1987-12-01
This report provides an archival record of the activities of the Engineering Physics and Mathematics Division during the period June 30, 1985 through September 30, 1987. Work in Mathematical Sciences continues to include applied mathematics research, statistics research, and computer science. Nuclear-data measurements and evaluations continue for fusion reactors, fission reactors, and other nuclear systems. Also discussed are long-standing studies of fission-reactor shields through experiments and related analysis, of accelerator shielding, and of fusion-reactor neutronics. Work in Machine Intelligence continues to feature the development of an autonomous robot. The last descriptive part of this report reflects the work in our Engineering Physics Information Center, which again concentrates primarily upon radiation-shielding methods and related data.
Engineering Physics and Mathematics Division progress report for period ending March 31, 1991
International Nuclear Information System (INIS)
1991-10-01
The primary purpose of this report is to provide an archival record of the activities of the Engineering Physics and Mathematics Division during the period September 1, 1989 through March 31, 1991. Earlier reports in this series are identified on the previous pages, along with the progress reports describing ORNL's research on the mathematical sciences prior to 1984 when those activities moved into the division. As in previous reports, our research is described through abstracts of journal articles, technical reports, and presentations. Summary lists of publications and presentations, staff additions and departures, scientific and professional activities of division staff, and technical conferences organized and sponsored by the division are included as appendices. The report is organized following the division of our research among four sections and information centers. These research areas are: Mathematical Sciences; Nuclear Data Measurement and Evaluations; Intelligent Systems; Nuclear Analysis and Shielding; and Engineering Physics Information Center
Engineering Physics and Mathematics Division progress report for period ending September 30, 1987
International Nuclear Information System (INIS)
1987-12-01
This report provides an archival record of the activities of the Engineering Physics and Mathematics Division during the period June 30, 1985 through September 30, 1987. Work in Mathematical Sciences continues to include applied mathematics research, statistics research, and computer science. Nuclear-data measurements and evaluations continue for fusion reactors, fission reactors, and other nuclear systems. Also discussed are long-standing studies of fission-reactor shields through experiments and related analysis, of accelerator shielding, and of fusion-reactor neutronics. Work in Machine Intelligence continues to feature the development of an autonomous robot. The last descriptive part of this report reflects the work in our Engineering Physics Information Center, which again concentrates primarily upon radiation-shielding methods and related data
Performance of engineering undergraduate students in mathematics: A case study in UniMAP
Saad, Syafawati Ab.; Azziz, Nor Hizamiyani Abdul; Zakaria, Siti Aisyah; Yazid, Nornadia Mohd
2015-12-01
The purpose of this paper is to study the trend performance of the first year engineering students at a public university in Mathematics course: Engineering Mathematics I. We analyze how ethnicity factor influenced students' performance in mathematics course over three years period. The performance of the undergraduate students in this study is measured by their cumulative grade point average (CGPA) in the first semester. Analysis of Variance (ANOVA) will be used to test the significance difference between three variables (Malay, Chinese and Indian). Method of simple linear regression (SLR) is used to test the relationship between the performances and to predict the future performance for this course. The findings of the study show that Chinese students perform better than Malay and Indian students.
Lobato, Fran Sérgio
2017-01-01
This book is aimed at undergraduate and graduate students in applied mathematics or computer science, as a tool for solving real-world design problems. The present work covers fundamentals in multi-objective optimization and applications in mathematical and engineering system design using a new optimization strategy, namely the Self-Adaptive Multi-objective Optimization Differential Evolution (SA-MODE) algorithm. This strategy is proposed in order to reduce the number of evaluations of the objective function through dynamic update of canonical Differential Evolution parameters (population size, crossover probability and perturbation rate). The methodology is applied to solve mathematical functions considering test cases from the literature and various engineering systems design, such as cantilevered beam design, biochemical reactor, crystallization process, machine tool spindle design, rotary dryer design, among others.
Lee, Sang Eun
2017-01-01
This dissertation examines gender differences in career advancement outcomes among academic science, technology, engineering and mathematics (STEM) scientists. In particular, this research examines effects of gender, PhD advisors and postdoctoral supervisors mentoring resources and gender homophily in the mentoring dyads on the career advancement…
Mathematical Modelling in Engineering: An Alternative Way to Teach Linear Algebra
Domínguez-García, S.; García-Planas, M. I.; Taberna, J.
2016-01-01
Technological advances require that basic science courses for engineering, including Linear Algebra, emphasize the development of mathematical strengths associated with modelling and interpretation of results, which are not limited only to calculus abilities. Based on this consideration, we have proposed a project-based learning, giving a dynamic…
Park, Mi-Hwa; Dimitrov, Dimiter M.; Patterson, Lynn G.; Park, Do-Yong
2017-01-01
The purpose of this study was to examine beliefs of early childhood teachers about their readiness for teaching science, technology, engineering, and mathematics, with a focus on testing for heterogeneity of such beliefs and differential effects of teacher-related factors. The results from latent class analysis of survey data revealed two latent…
Kovarik, Dina N.; Patterson, Davis G.; Cohen, Carolyn; Sanders, Elizabeth A.; Peterson, Karen A.; Porter, Sandra G.; Chowning, Jeanne Ting
2013-01-01
We investigated the effects of our Bio-ITEST teacher professional development model and bioinformatics curricula on cognitive traits (awareness, engagement, self-efficacy, and relevance) in high school teachers and students that are known to accompany a developing interest in science, technology, engineering, and mathematics (STEM) careers. The…
Women's Leadership in Science, Technology, Engineering and Mathematics: Barriers to Participation
McCullough, Laura
2011-01-01
Despite gains overall, women are still under-represented in leadership positions in science, technology, engineering, and mathematics (STEM) fields. Data in the US suggest around one-quarter of deans and department heads are women; in science this drops to nearly 1 in 20. Part of this problem of under-representation stems from the population pool:…
Women of Color in Mathematics, Science & Engineering: A Review of the Literature.
Clewell, Beatriz Chu; Anderson, Bernice
This review of the literature on women of color in mathematics, science, and engineering helps define the need for a national agenda for equity in these fields sponsored by the Educational Equity Policy Studies Program of the Center for Women Policy Studies, and for a comprehensive research program that examines barriers to the participation of…
Leadership Training in Science, Technology, Engineering and Mathematics Education in Bulgaria
Bairaktarova, Diana; Cox, Monica F.; Evangelou, Demetra
2011-01-01
This synthesis paper explores current leadership training in science, technology, engineering and mathematics (STEM) education in Bulgaria. The analysis begins with discussion of global factors influencing the implementation of leadership training in STEM education in general and then presents information about the current status of leadership…
Puzzle-Based Learning in Engineering Mathematics: Students' Attitudes
Klymchuk, Sergiy
2017-01-01
The article reports on the results of two case studies on the impact of the regular use of puzzles as a pedagogical strategy in the teaching and learning of engineering mathematics. The intention of using puzzles is to engage students' emotions, creativity and curiosity and also to enhance their generic thinking skills and lateral thinking…
Koyunlu Unlu, Zeynep; Dokme, Ilbilge; Unlu, Veli
2016-01-01
Problem Statement: Science, technology, engineering, and mathematics (STEM) education has recently become a remarkable research topic, especially in developed countries as a result of the skilled workforce required in the fields of the STEM. Considering that professional tendencies are revealed at early ages, determining students' interest in STEM…
Cusker, Jeremy; Rauh, Anne E.
2014-01-01
Discussions of the potential of open access publishing frequently must contend with the skepticism of research authors regarding the need to pay author fees (also known as publication fees). With that in mind, the authors undertook a survey of faculty, postdocs, and graduate students in physical science, mathematics, and engineering fields at two…
Psycho-Social Determinants of Gender Prejudice in Science, Technology, Engineering and Mathematics
Nnachi, N. O.; Okpube, M. N.
2015-01-01
This work focused on the "Psycho-social Determinants of Gender Prejudice in Science, Technology, Engineering and Mathematics (STEM)". The females were found to be underrepresented in STEM fields. The under-representation results from gender stereotype, differences in spatial skills, hierarchical and territorial segregations and…
Greenseid, Lija O.; Lawrenz, Frances
2011-01-01
This study explores the use of citation analysis methods to assess the influence of program evaluations conducted within the area of science, technology, engineering, and mathematics (STEM) education. Citation analysis is widely used within scientific research communities to measure the relative influence of scientific research enterprises and/or…
Nkere, Nsidi
2016-01-01
A qualitative case study was conducted by examining the perceptions of fifth-grade African American girls about their experiences with science, technology, engineering and mathematics (STEM) education and potential for STEM as a future career. As the United States suffers from waning participation across all demographics in STEM and a high level…
Jensen, Jamie L.; Neeley, Shannon; Hatch, Jordan B.; Piorczynski, Ted
2017-01-01
The United States produces too few Science, Technology, Engineering, and Mathematics (STEM) graduates to meet demand. We investigated scientific reasoning ability as a possible factor in STEM retention. To do this, we classified students in introductory biology courses at a large private university as either declared STEM or non-STEM majors and…
Torcivia, Patrice Prusko
2012-01-01
Numerous studies have addressed science, technology, engineering and mathematics (STEM) and their relation to education and gender ranging from elementary school pedagogy to career choices for traditional-aged college students. Little research has addressed nontraditional female students returning to the university to in the STEM fields. This…
Leddy, Mark H.
2010-01-01
Americans with disabilities are underemployed in science, technology, engineering and mathematics (STEM) at higher rates than their nondisabled peers. This article provides an overview of the National science Foundation's Research in Disabilities Education (RDE) program, of technology use by students with disabilities (SWD) in STEM, and of…
"MathePraxis"--Connecting First-Year Mathematics with Engineering Applications
Harterich, Jorg; Kiss, Christine; Rooch, Aeneas; Monnigmann, Martin; Darup, Moritz Schulze; Span, Roland
2012-01-01
First-year engineering students often complain about their mathematics courses as the significance of the difficult and abstract calculus to their field of study remains unclear. We report on the project "MathePraxis", a feasibility study which was designed as a means to give first-year students some impression about the use of…
Martinez, Alina; Cosentino de Cohen, Clemencia
2010-01-01
This report presents findings from a NASA requested evaluation in 2008, which contains both implementation and impact modules. The implementation study investigated how sites implement Science, Engineering, Mathematics, and Aerospace Academy (SEMAA) and the contextual factors important in this implementation. The implementation study used data…
Karahan, Engin; Canbazoglu Bilici, Sedef; Unal, Aycin
2015-01-01
Problem Statement: Science, technology, engineering and mathematics (STEM) education aims at improving students' knowledge and skills in science and math, and thus their attitudes and career choices in these areas. The ultimate goal in STEM education is to create scientifically literate individuals who can survive in the global economy. The…
Mathematical model of marine diesel engine simulator for a new methodology of self propulsion tests
Energy Technology Data Exchange (ETDEWEB)
Izzuddin, Nur; Sunarsih,; Priyanto, Agoes [Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia)
2015-05-15
As a vessel operates in the open seas, a marine diesel engine simulator whose engine rotation is controlled to transmit through propeller shaft is a new methodology for the self propulsion tests to track the fuel saving in a real time. Considering the circumstance, this paper presents the real time of marine diesel engine simulator system to track the real performance of a ship through a computer-simulated model. A mathematical model of marine diesel engine and the propeller are used in the simulation to estimate fuel rate, engine rotating speed, thrust and torque of the propeller thus achieve the target vessel’s speed. The input and output are a real time control system of fuel saving rate and propeller rotating speed representing the marine diesel engine characteristics. The self-propulsion tests in calm waters were conducted using a vessel model to validate the marine diesel engine simulator. The simulator then was used to evaluate the fuel saving by employing a new mathematical model of turbochargers for the marine diesel engine simulator. The control system developed will be beneficial for users as to analyze different condition of vessel’s speed to obtain better characteristics and hence optimize the fuel saving rate.
Two-phase plate-fin heat exchanger modeling for waste heat recovery systems in diesel engines
Feru, E.; Jager, de A.G.; Willems, F.P.T.; Steinbuch, M.
2014-01-01
This paper presents the modeling and model validation for a modular two-phase heat exchanger that recovers energy in heavy-duty diesel engines. The model is developed for temperature and vapor quality prediction and for control design of the waste heat recovery system. In the studied waste heat
Ecological optimization of an irreversible quantum Carnot heat engine with spin-1/2 systems
International Nuclear Information System (INIS)
Liu Xiaowei; Chen Lingen; Wu Feng; Sun Fengrui
2010-01-01
A model of a quantum heat engine with heat resistance, internal irreversibility and heat leakage and many non-interacting spin-1/2 systems is established in this paper. The quantum heat engine cycle is composed of two isothermal processes and two irreversible adiabatic processes and is referred to as a spin quantum Carnot heat engine. Based on the quantum master equation and the semi-group approach, equations of some important performance parameters, such as power output, efficiency, entropy generation rate and ecological function (a criterion representing the optimal compromise between exergy output rate and exergy loss rate), for the irreversible spin quantum Carnot heat engine are derived. The optimal ecological performance of the heat engine in the classical limit is analyzed with numerical examples. The effects of internal irreversibility and heat leakage on ecological performance are discussed in detail.
Tully, D.; Jacobs, B.
2010-08-01
This study focused on a population of female engineering students, probing the influences of their secondary school experience on their choice to pursue an engineering course of study at university. The motivating question is: Do unique opportunities exist in an all-female secondary school mathematics classroom, which impact a young woman's self-perception of her mathematics ability as well as promote a positive path towards an engineering-based university major? Using both qualitative and quantitative data collection instruments, this study examined a sample of Australian engineering students enrolled at the University of Technology, Sydney (UTS). Demographic statistics show that 40% of UTS' female engineering student population attended a single-gender secondary school, indicating a potential influence of school type (single-gender) on engineering enrolment patterns. Female students were primarily motivated to pursue a post secondary engineering path because of a self-belief that they are good at mathematics. In contrast, male students were more influenced by positive male role models of family members who are practising engineers. In measures of self- perception of mathematical skill and ability, female students from single-gender schools outscored their male engineering counterparts. Additionally, female students seem to benefit from verbal encouragement, contextualisation, same gender problem-solving groups and same gender classroom dynamics.
Many-objective thermodynamic optimization of Stirling heat engine
International Nuclear Information System (INIS)
Patel, Vivek; Savsani, Vimal; Mudgal, Anurag
2017-01-01
This paper presents a rigorous investigation of many-objective (four-objective) thermodynamic optimization of a Stirling heat engine. Many-objective optimization problem is formed by considering maximization of thermal efficiency, power output, ecological function and exergy efficiency. Multi-objective heat transfer search (MOHTS) algorithm is proposed and applied to obtain a set of Pareto-optimal points. Many objective optimization results form a solution in a four dimensional hyper objective space and for visualization it is represented on a two dimension objective space. Thus, results of four-objective optimization are represented by six Pareto fronts in two dimension objective space. These six Pareto fronts are compared with their corresponding two-objective Pareto fronts. Quantitative assessment of the obtained Pareto solutions is reported in terms of spread and the spacing measures. Different decision making approaches such as LINMAP, TOPSIS and fuzzy are used to select a final optimal solution from Pareto optimal set of many-objective optimization. Finally, to reveal the level of conflict between these objectives, distribution of each decision variable in their allowable range is also shown in two dimensional objective spaces. - Highlights: • Many-objective (i.e. four objective) optimization of Stirling engine is investigated. • MOHTS algorithm is introduced and applied to obtain a set of Pareto points. • Comparative results of many-objective and multi-objectives are presented. • Relationship of design variables in many-objective optimization are obtained. • Optimum solution is selected by using decision making approaches.
Multilevel quantum Otto heat engines with identical particles
Huang, X. L.; Guo, D. Y.; Wu, S. L.; Yi, X. X.
2018-02-01
A quantum Otto heat engine is studied with multilevel identical particles trapped in one-dimensional box potential as working substance. The symmetrical wave function for Bosons and the anti-symmetrical wave function for Fermions are considered. In two-particle case, we focus on the ratios of W^i (i=B,F) to W_s, where W^B and W^F are the work done by two Bosons and Fermions, respectively, and W_s is the work output of a single particle under the same conditions. Due to the symmetrical of the wave functions, the ratios are not equal to 2. Three different regimes, low-temperature regime, high-temperature regime, and intermediate-temperature regime, are analyzed, and the effects of energy level number and the differences between the two baths are calculated. In the multiparticle case, we calculate the ratios of W^i_M/M to W_s, where W^i_M/M can be seen as the average work done by a single particle in multiparticle heat engine. For other working substances whose energy spectrum has the form of E_n˜ n^2, the results are similar. For the case E_n˜ n, two different conclusions are obtained.
Recovery of Exhaust Waste Heat for ICE Using the Beta Type Stirling Engine
Directory of Open Access Journals (Sweden)
Wail Aladayleh
2015-01-01
Full Text Available This paper investigates the potential of utilizing the exhaust waste heat using an integrated mechanical device with internal combustion engine for the automobiles to increase the fuel economy, the useful power, and the environment safety. One of the ways of utilizing waste heat is to use a Stirling engine. A Stirling engine requires only an external heat source as wasted heat for its operation. Because the exhaust gas temperature may reach 200 to 700°C, Stirling engine will work effectively. The indication work, real shaft power and specific fuel consumption for Stirling engine, and the exhaust power losses for IC engine are calculated. The study shows the availability and possibility of recovery of the waste heat from internal combustion engine using Stirling engine.
9 CFR 91.22 - Protection from heat of boilers and engines.
2010-01-01
... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Protection from heat of boilers and... Protection from heat of boilers and engines. No animals shall be stowed along the alleyways leading to the engine or boiler rooms unless the sides of said engine or boiler rooms are covered by a tongue and groove...
Elements of learning technologies designing of engineering networks heat
Directory of Open Access Journals (Sweden)
Sidorkina Irina G.
2016-01-01
Full Text Available Modern educational systems function as a medium fast analysis of shared information that defines them as analytical. The purpose of analytical information processing systems: working with distributed data on a global computer networks, mining and processing of semi structured information, knowledge. Existing mathematical and heuristic methods for the automated synthesis of electronic courses and their corresponding algorithms do not allow the full compliance of development realized in the form of adequate criteria for the totality of the properties distributed educational systems within acceptable time limits and characteristic. Therefore, the development of electronic educational applications must be accompanied by a variety of software support intelligent and adaptive functions. In addition, there is no theoretical justification for integrative aspects and their practical applications for intelligent and adaptive systems of designing distance learning courses. Currently, this type of problem may be considered as a potentially promising. The article presents the functionality of the e-learning course on the design engineering of thermal networks, process modeling in engineering networks with the solution of energy efficiency, detection of problem areas; identify the irrational layout of heaters and others.
Mathematical modelling of heat production in deep geological repository of high-level nuclear waste
International Nuclear Information System (INIS)
Kovanda, O.
2017-01-01
Waste produced by nuclear industry requires special handling. Currently, there is a research taking place, focused at possibilities of nuclear waste storage in deep geological repositories, hosted in stable geological environment. The high-level nuclear waste produces significant amount of heat for a long time, which can affect either environment outside of or within the repository in a negative way. Therefore to reduce risks, it is desirable to know the principles of such heat production, which can be achieved using mathematical modeling. This thesis comes up with a general model of heat production-time dependency, dependable on initial composition of the waste. To be able to model real situations, output of this thesis needs to be utilized in an IT solution. (authors)
Directory of Open Access Journals (Sweden)
Shestakov Igor A.
2015-01-01
Full Text Available The article shows the results of mathematical modeling of convective heat transfer in the low-temperature storage of liquefied natural gas. Regime of natural convection in an enclosure with different intensity of the heat flux at the external borders are investigated. Was examined two-dimensional nonstationary problem within the model of Navier-Stokes in dimensionless variables “vorticity - stream function - temperature”. Distributions of hydrodynamic parameters and temperatures that characterize the basic regularities of the processes are obtained. Circulating flows are determined and carried out the analysis of vortices formation mechanism and the temperature distribution in solution at conditions of natural convection when the Grashof number (Gr = 106. A significant influence of heat transfer rate on solutions boundary on flow structure and temperature field in LNG storage tanks.
The atmospheric heat engine response to climate change
Pauluis, O. M.
2014-12-01
Moist convection is characterized by complex interactions between dynamics and thermodynamics. As air parcels within the atmosphere, they experience multiple thermodynamic transformations, such as compression and expansion, diabatic heating and cooling, condensation and mixing. These transformations correspond to those of a heat engine that produces kinetic energy while transporting energy from a warm source to a colder sink. This atmospheric heat engine is however directly affected by moist processes. First, falling precipitation acts as a break on the circulation by dissipating a significant amount of kinetic energy. Second, evaporation of unsaturated water and diffusion of water vapor are irrevesible processes that also reduce the amount of work that can be produced. An important challenge is to quantify the impacts that these two effects have on the generation of kinetic energy. Here, I will introduce a new technique - the Mean Air Flow As Lagragian Dynamics Approximation (MAFALDA) - that can be used to systematically analyze the thermodynamic behavior of complex atmospheric flows. This approach relies on sorting the upward mass transport in terms of the equivalent potential temperature of the air parcels to obtain an isentropic streamfunction. This streamfunction is then used to determine the thermodynamic evolution of air parcels as they move through the atmosphere. This approach is applied to analyze how convective systems would behave in a warmer climate. It is shown that an increase in atmospheric temperature lead to a significant increase of the amount of kinetic energy that is produced per unit of mass of air transported. At the same time, the total generation of kinetic energy is only slightly affected. Taken together, these findings imply that, in a warming atmosphere, the number of intense convective events will be reduced, while their intensity should increase. I will also discuss the new possibility of systematically studying the thermodynamic
Directory of Open Access Journals (Sweden)
Chia-En Ho
2012-09-01
Full Text Available This paper investigates the optimization of the performance of a solar powered Stirling engine based on finite-time thermodynamics. Heat transference in the heat exchangers between a concentrating solar collector and the Stirling engine is studied. The irreversibility of a Stirling engine is considered with the heat transfer following Newton's law. The power generated by a Stirling engine is used as an objective function for maximum power output design with the concentrating solar collector temperature and the engine thermal efficiency as the optimization parameters. The maximum output power of engine and its corresponding system parameters are determined using a genetic algorithm.
Continuum mechanics the birthplace of mathematical models
Allen, Myron B
2015-01-01
Continuum mechanics is a standard course in many graduate programs in engineering and applied mathematics as it provides the foundations for the various differential equations and mathematical models that are encountered in fluid mechanics, solid mechanics, and heat transfer. This book successfully makes the topic more accessible to advanced undergraduate mathematics majors by aligning the mathematical notation and language with related courses in multivariable calculus, linear algebra, and differential equations; making connections with other areas of applied mathematics where parial differe
Effect of translucence of engineering ceramics on heat transfer in diesel engines. Final report
Energy Technology Data Exchange (ETDEWEB)
Wahiduzzaman, S.; Morel, T. [Integral Technologies, Inc., Westmont, IL (United States)
1992-04-01
This report describes the experimental portion of a broader study undertaken to assess the effects of translucence of ceramic materials used as thermal barrier coatings in diesel engines. In an earlier analytical work a parametric study was performed, varying several radiative properties over ranges typical of engineering ceramics, thereby identifying the most important radiative properties and their impact on in-cylinder heat transfer. In the current study these properties were experimentally determined for several specific zirconia coatings considered for thermal barrier applications in diesel engines. The methodology of this study involved formulation of a model capable of describing radiative transfer through a semitransparent medium as a function of three independent model parameters, ie, absorption coefficient, scattering coefficient and refractive index. For the zirconia-based ceramics investigated in this study, it was concluded that for usual coating thicknesses (1.5--2.5 mm) these ceramics are optically thick and hence, are effective as radiative heat transfer barriers. These ceramics possess high scattering coefficients and low absorption coefficients causing them to be highly reflective (60-80%) in the spectral region where thermal radiation is important. The performance of the investigated ceramics and the mechanism of heat transfer were found to depend on surface condition, specifically on soot deposition. Thus, to insure the optimum thermal barrier operation for either clean or heavily sooted surfaces, a ceramic material with high scattering coefficient provides the best choice.
Effect of translucence of engineering ceramics on heat transfer in diesel engines
Energy Technology Data Exchange (ETDEWEB)
Wahiduzzaman, S.; Morel, T. (Integral Technologies, Inc., Westmont, IL (United States))
1992-04-01
This report describes the experimental portion of a broader study undertaken to assess the effects of translucence of ceramic materials used as thermal barrier coatings in diesel engines. In an earlier analytical work a parametric study was performed, varying several radiative properties over ranges typical of engineering ceramics, thereby identifying the most important radiative properties and their impact on in-cylinder heat transfer. In the current study these properties were experimentally determined for several specific zirconia coatings considered for thermal barrier applications in diesel engines. The methodology of this study involved formulation of a model capable of describing radiative transfer through a semitransparent medium as a function of three independent model parameters, ie, absorption coefficient, scattering coefficient and refractive index. For the zirconia-based ceramics investigated in this study, it was concluded that for usual coating thicknesses (1.5--2.5 mm) these ceramics are optically thick and hence, are effective as radiative heat transfer barriers. These ceramics possess high scattering coefficients and low absorption coefficients causing them to be highly reflective (60-80%) in the spectral region where thermal radiation is important. The performance of the investigated ceramics and the mechanism of heat transfer were found to depend on surface condition, specifically on soot deposition. Thus, to insure the optimum thermal barrier operation for either clean or heavily sooted surfaces, a ceramic material with high scattering coefficient provides the best choice.
Rodionova, N. S.; Popov, E. S.; Pozhidaeva, E. A.; Pynzar, S. S.; Ryaskina, L. O.
2018-05-01
The aim of this study is to develop a mathematical model of the heat exchange process of LT-processing to estimate the dynamics of temperature field changes and optimize the regime parameters, due to the non-stationarity process, the physicochemical and thermophysical properties of food systems. The application of LT-processing, based on the use of low-temperature modes in thermal culinary processing of raw materials with preliminary vacuum packaging in a polymer heat- resistant film is a promising trend in the development of technics and technology in the catering field. LT-processing application of food raw materials guarantees the preservation of biologically active substances in food environments, which are characterized by a certain thermolability, as well as extend the shelf life and high consumer characteristics of food systems that are capillary-porous bodies. When performing the mathematical modeling of the LT-processing process, the packet of symbolic mathematics “Maple” was used, as well as the mathematical packet flexPDE that uses the finite element method for modeling objects with distributed parameters. The processing of experimental results was evaluated with the help of the developed software in the programming language Python 3.4. To calculate and optimize the parameters of the LT processing process of polycomponent food systems, the differential equation of non-stationary thermal conductivity was used, the solution of which makes it possible to identify the temperature change at any point of the solid at different moments. The present study specifies data on the thermophysical characteristics of the polycomponent food system based on plant raw materials, with the help of which the physico-mathematical model of the LT- processing process has been developed. The obtained mathematical model allows defining of the dynamics of the temperature field in different sections of the LT-processed polycomponent food systems on the basis of calculating the
Biogas Engine Waste Heat Recovery Using Organic Rankine Cycle
Directory of Open Access Journals (Sweden)
Alberto Benato
2017-03-01
Full Text Available Italy is a leading country in the biogas sector. Energy crops and manure are converted into biogas using anaerobic digestion and, then, into electricity using internal combustion engines (ICEs. Therefore, there is an urgent need for improving the efficiency of these engines taking the real operation into account. To this purpose, in the present work, the organic Rankine cycle (ORC technology is used to recover the waste heat contained in the exhaust gases of a 1 MWel biogas engine. The ICE behavior being affected by the biogas characteristics, the ORC unit is designed, firstly, using the ICE nameplate data and, then, with data measured during a one-year monitoring activity. The optimum fluid and the plant configuration are selected in both cases using an “in-house” optimization tool. The optimization goal is the maximization of the net electric power while the working fluid is selected among 115 pure fluids and their mixtures. Results show that a recuperative ORC designed using real data guarantees a 30% higher net electric power than the one designed with ICE nameplate conditions.
Bizarro, João P S; Rodrigues, Paulo
2012-11-01
For work-producing heat engines, or work-consuming refrigerators and heat pumps, the percentage decrease caused by friction in their efficiencies, or coefficients of performance (COP's), is approximately given by the ratio W(fric)/W between the work spent against friction forces and the work performed by, or delivered to, the working fluid. This universal scaling, which applies in the limit of small friction (W(fric)/W heat-engine efficiencies), allows a simple and quick estimate of the impact that friction losses can have on the FOM's of thermal engines and plants, or of the level of those losses from the observed and predicted FOM's. In the case of refrigerators and heat pumps, if W(fric)/W heat engines), the COP percentage decrease due to friction approaches asymptotically (W(fric)/W)/(1+W(fric)/W) instead of W(fric)/W. Estimates for the level of frictional losses using the Carnot (or, for heat engines and power plants only, the Curzon-Ahlborn) predictions and observed FOM's of real power plants, heat engines, refrigerators, and heat pumps show that they usually operate in domains where these behaviors are valid.
Study of heat insulated turbo compound engine. Shanetsugata tabo konpaundo engine to tomoni ayumu
Energy Technology Data Exchange (ETDEWEB)
Hirai, K [Isuzu Motors Ltd., Tokyo (Japan). Ceramics Research Lab.
1994-02-01
For a main purpose of development of the heat insulated turbo compound engine using the ceramics, the Isuzu Ceramics Inst. Co., Ltd. was established by the Isuzu Motors Ltd. in 1988. The main study subjects take up various topics such as a development of the new engine system for actualizing a low fuel consumption and low emission, an improvement of deteriorated combustion caused by the insulation, a development of energy recovery facility for utilizing effectively the exhaust energy from the engines, a development of power electronics technology for controlling the recovery facility, a study and development of ceramics as the insulation material and so forth. The outstanding characteristics of this institute are that a development of the heat insulated turbo compound engine is set as the main study subject, but at the same time that a commercialization of the various derivation technology derived from this study. Even just the main study subjects currently under way are counted up to a number close to 10 items, and consequently the efforts are being continued in each field assigned for solving the subjects. 6 figs.
Tully, D.; Jacobs, B.
2010-01-01
This study focused on a population of female engineering students, probing the influences of their secondary school experience on their choice to pursue an engineering course of study at university. The motivating question is: Do unique opportunities exist in an all-female secondary school mathematics classroom, which impact a young woman's…
Mathematical Model for the Sequential Action of Radiation and Heat on Yeast Cells
International Nuclear Information System (INIS)
Kim, Jin Kyu; Lee, Yun Jong; Kim, Su Hyoun; Nili, Mohammad; Zhurakovskaya, Galina P.; Petin, Vladislav G.
2009-01-01
It is well known that the synergistic interaction of hyperthermia with ionizing radiation and other agents is widely used in hyperthermic oncology. Interaction between two agents may be considered as synergistic or antagonistic when the effect produced is greater or smaller than the sum of the two single responses. It has long be considered that the mechanism of synergistic interaction of hyperthermia and ionizing radiation may be brought about by an inhibition of the repair from sublethal and potentially lethal damage at the cellular level. The inhibition of the recovery process after combined treatments cannot be considered as a reason for the synergy, but rather would be the expected and predicted consequence of the production of irreversible damage. On the basis of it, a simple mathematical model of the synergistic interaction of two agents acting simultaneously has been proposed. However, the model has not been applied to predict the degree of interaction of heat and ionizing radiation after their sequential action. Extension of the model to the sequential treatment of heat and ionizing radiation seems to be of interest for theoretical and practical reasons. Thus, the purposes of the present work is to suggest the simplest mathematical model which would be able to account for the results obtained and currently available experimental information on the sequential action of radiation and heat.
Consideration on nuclear fusion in plasma by the magnetic confinement as a heat engine
International Nuclear Information System (INIS)
Tsuji, Yoshio
1990-01-01
In comparing nuclear fusion in plasma by the magnetic confinement with nuclear fission and chemical reactions, the power density and the function of a heat engine are discussed using a new parameter G introduced as an eigenvalue of a reaction and the value of q introduced to estimate the thermal efficiency of a heat engine. It is shown that the fusion reactor by the magnetic confinement is very difficult to be a modern heat engine because of the lack of some indispensable functions as a modern heat engine. The value of G and q have the important role in the consideration. (author)
Effectiveness-ntu computation with a mathematical model for cross-flow heat exchangers
Directory of Open Access Journals (Sweden)
H. A. Navarro
2007-12-01
Full Text Available Due to the wide range of design possibilities, simple manufactured, low maintenance and low cost, cross-flow heat exchangers are extensively used in the petroleum, petrochemical, air conditioning, food storage, and others industries. In this paper a mathematical model for cross-flow heat exchangers with complex flow arrangements for determining epsilon -NTU relations is presented. The model is based on the tube element approach, according to which the heat exchanger outlet temperatures are obtained by discretizing the coil along the tube fluid path. In each cross section of the element, tube-side fluid temperature is assumed to be constant because the heat capacity rate ratio C*=Cmin/Cmax tends toward zero in the element. Thus temperature is controlled by effectiveness of a local element corresponding to an evaporator or a condenser-type element. The model is validated through comparison with theoretical algebraic relations for single-pass cross-flow arrangements with one or more rows. Very small relative errors are obtained showing the accuracy of the present model. epsilon -NTU curves for several complex circuit arrangements are presented. The model developed represents a useful research tool for theoretical and experimental studies on heat exchangers performance.
Mathematical model of solid food pasteurization by ohmic heating: influence of process parameters.
Marra, Francesco
2014-01-01
Pasteurization of a solid food undergoing ohmic heating has been analysed by means of a mathematical model, involving the simultaneous solution of Laplace's equation, which describes the distribution of electrical potential within a food, the heat transfer equation, using a source term involving the displacement of electrical potential, the kinetics of inactivation of microorganisms likely to be contaminating the product. In the model, thermophysical and electrical properties as function of temperature are used. Previous works have shown the occurrence of heat loss from food products to the external environment during ohmic heating. The current model predicts that, when temperature gradients are established in the proximity of the outer ohmic cell surface, more cold areas are present at junctions of electrodes with lateral sample surface. For these reasons, colder external shells are the critical areas to be monitored, instead of internal points (typically geometrical center) as in classical pure conductive heat transfer. Analysis is carried out in order to understand the influence of pasteurisation process parameters on this temperature distribution. A successful model helps to improve understanding of these processing phenomenon, which in turn will help to reduce the magnitude of the temperature differential within the product and ultimately provide a more uniformly pasteurized product.
Heat engines for dilatonic Born-Infeld black holes
Energy Technology Data Exchange (ETDEWEB)
Bhamidipati, Chandrasekhar; Yerra, Pavan Kumar [Indian Institute of Technology Bhubaneswar, School of Basic Sciences, Bhubaneswar (India)
2017-08-15
In the context of dilaton coupled Einstein gravity with a negative cosmological constant and a Born-Infeld field, we study heat engines where a charged black hole is the working substance. Using the existence of a notion of thermodynamic mass and volume (which depend on the dilaton coupling), the mechanical work takes place via the pdV terms present in the first law of extended gravitational thermodynamics. The efficiency is analyzed as a function of dilaton and Born-Infeld couplings, and the results are compared with analogous computations in the related conformal solutions in the Brans-Dicke-Born-Infeld theory and black holes in anti-de Sitter space-time. (orig.)
Advanced materials for alternative fuel capable directly fired heat engines
Energy Technology Data Exchange (ETDEWEB)
Fairbanks, J.W.; Stringer, J. (eds.)
1979-12-01
The first conference on advanced materials for alternative fuel capable directly fired heat engines was held at the Maine Maritime Academy, Castine, Maine. It was sponsored by the US Department of Energy, (Assistant Secretary for Fossil Energy) and the Electric Power Research Institute, (Division of Fossil Fuel and Advanced Systems). Forty-four papers from the proceedings have been entered into EDB and ERA and one also into EAPA; three had been entered previously from other sources. The papers are concerned with US DOE research programs in this area, coal gasification, coal liquefaction, gas turbines, fluidized-bed combustion and the materials used in these processes or equipments. The materials papers involve alloys, ceramics, coatings, cladding, etc., and the fabrication and materials listing of such materials and studies involving corrosion, erosion, deposition, etc. (LTN)
Contributions in mathematics and engineering in honor of Constantin Carathéodory
Rassias, Themistocles
2016-01-01
The contributions in this volume aim to deepen the researcher's understanding of some of the current research problems and theories in modern topics such as calculus of variations, optimization theory, complex analysis, real analysis, differential equations, and geometry. Applications to these areas of mathematics are presented within the broad spectrum of research in Engineering Science with particular emphasis on equilibrium problems, complexity in numerical optimization, dynamical systems, non-smooth optimization, complex network analysis, statistical models and data mining, and energy systems. Additional emphasis is given to interdisciplinary research, although subjects are treated in a unified and self-contained manner. The presentation of methods, theory and applications makes this tribute an invaluable reference for teachers, researchers, and other professionals interested in pure and applied research, philosophy of mathematics, and mathematics education. Some review papers published in this volume wil...
2014-01-01
This highly multidisciplinary volume contains contributions from leading researchers in STEAM-H disciplines (Science, Technology, Engineering, Agriculture, Mathematics and Health). The volume explores new frontiers in multidisciplinary research, including: the mathematics of cardiac arrhythmia; brain research on working memory; penalized ordinal regression to classify melanoma skin samples; forecasting of time series data; dynamics of niche models; analysis of chemical moieties as anticancer agents; study of gene locus control regions; qualitative mathematical modelling; convex quadrics and group circle systems; remanufacturing planning and control; complexity reduction of functional differential equations; computation of viscous interfacial motion; and differentiation in human pluripotent stem cells. An extension of a seminar series at Virginia State University, the collection is intended to foster student interest and participation in interdisciplinary research, and to stimulate new research. The content wi...
International Nuclear Information System (INIS)
Olsen, D.A.
1991-01-01
The authors constructed an apparatus to measure heat transfer coefficients in compact heat exchangers which are candidate cooling jackets for the engine struts of the National Aerospace Plane. This paper reports measurements on a tube specimen heat exchanger. The heat exchanger consisted of 20 nickel tubes (2 mm OD, 1 mm ID, 15.2 cm heated length), brazed to a 3 mm thick nickel plate. The tubes lay parallel to one another, 3.8 mm on-center separation. The heat exchanger was heated on one side in a radiative furnace at heat fluxes of 3.4 to 54 W/cm 2 over a normal area of 7.8 cm by 15.2 cm. The coolant fluid was helium gas at Reynolds numbers of 3000 to 35 000 and 3.50 MPa pressure. For high heat flux and low
Mathematical model of an indirect action fuel flow controller for aircraft jet engines
Tudosie, Alexandru-Nicolae
2017-06-01
The paper deals with a fuel mass flow rate controller with indirect action for aircraft jet engines. The author has identified fuel controller's main parts and its operation mode, then, based on these observations, one has determined motion equations of each main part, which have built system's non-linear mathematical model. In order to realize a better study this model was linearised (using the finite differences method) and then adimensionalized. Based on this new form of the mathematical model, after applying Laplace transformation, the embedded system (controller+engine) was described by the block diagram with transfer functions. Some Simulink-Matlab simulations were performed, concerning system's time behavior for step input, which lead to some useful conclusions and extension possibilities.
International Nuclear Information System (INIS)
Zhao, Yingru; Chen, Jincan
2007-01-01
An irreversible cycle model of the Diesel heat engine is established in which the temperature dependent heat capacities of the working fluid, the irreversibilities resulting from non-isentropic compression and expansion processes and heat leak losses through the cylinder wall are taken into account. The adiabatic equation of ideal gases with temperature dependent heat capacity is strictly deduced without using the additional approximation condition in the relevant literature and is used to analyze the performance of the Diesel heat engine. Expressions for the work output and efficiency of the cycle are derived by introducing the pressure ratio and the compression and expansion efficiencies. The performance characteristic curves of the Diesel heat engine are presented for a set of given parameters. The optimum criteria of some important parameters such as the work output, efficiency, pressure ratio and temperatures of the working fluid are obtained. Moreover, the influence of the compression and expansion efficiencies, variable heat capacities, heat leak and other parameters on the performance of the cycle is discussed in detail. The results obtained may provide a theoretical basis for both optimal design and operation of real Diesel heat engines
Elementary mathematical and computational tools for electrical and computer engineers using Matlab
Manassah, Jamal T
2013-01-01
Ideal for use as a short-course textbook and for self-study Elementary Mathematical and Computational Tools for Electrical and Computer Engineers Using MATLAB fills that gap. Accessible after just one semester of calculus, it introduces the many practical analytical and numerical tools that are essential to success both in future studies and in professional life. Sharply focused on the needs of the electrical and computer engineering communities, the text provides a wealth of relevant exercises and design problems. Changes in MATLAB's version 6.0 are included in a special addendum.
Engineering Physics and Mathematics Division progress report for period ending December 31, 1992
Energy Technology Data Exchange (ETDEWEB)
Ward, R.C.
1993-05-01
In this report, our research is described through abstracts of journal articles, technical reports, and presentations organized into sections following the five major operating units in the division: Mathematical Sciences, Intelligent Systems, Nuclear Data and Measurement Analysis, Nuclear Analysis and Shielding, and the Engineering Physics Information Centers. Each section begins with an introduction highlighting honors, awards, and significant research accomplishments in that unit during the reporting period.
Engineering Physics and Mathematics Division progress report for period ending December 31, 1992
International Nuclear Information System (INIS)
Ward, R.C.
1993-05-01
In this report, our research is described through abstracts of journal articles, technical reports, and presentations organized into sections following the five major operating units in the division: Mathematical Sciences, Intelligent Systems, Nuclear Data and Measurement Analysis, Nuclear Analysis and Shielding, and the Engineering Physics Information Centers. Each section begins with an introduction highlighting honors, awards, and significant research accomplishments in that unit during the reporting period
Makaliuk Iryna V.
2014-01-01
The article identifies stages of the process of optimisation of transaction expenses. It develops an economic and mathematical model of optimisation of transaction expenses of engineering enterprises by the criterion of maximisation of income from realisation of products and system of restrictions, which envisages exceeding income growth rate over the expenses growth rate. The article offers to use types of expenses by accounting accounts as indicators of transaction expenses. In the result o...
Mathematical modeling and analysis of heat pipe start-up from the frozen state
International Nuclear Information System (INIS)
Jang, J.H.; Faghri, A.; Chang, W.S.; Mahefkey, E.T.
1989-08-01
The start-up process of a frozen heat pipe is described and a complete mathematical model for the start-up of the frozen heat pipe is developed based on the existing experimental data, which is simplified and solved numerically. The two-dimensional transient model for the wall and wick is coupled with the one-dimensional transient model for the vapor flow when vaporization and condensation occur at the interface. A parametric study is performed to examine the effect of the boundary specification at the surface of the outer wall on the successful start-up from the frozen state. For successful start-up, the boundary specification at the outer wall surface must melt the working substance in the condenser before dry-out takes place in the evaporator
Heat integration of an Olefins Plant: Pinch Analysis and mathematical optimization working together
Directory of Open Access Journals (Sweden)
M. Beninca
2011-03-01
Full Text Available This work explores a two-step, complexity reducing methodology, to analyze heat integration opportunities of an existing Olefins Plant, identify and quantify reduction of energy consumption, and propose changes of the existing heat exchanger network to achieve these goals. Besides the analysis of plant design conditions, multiple operational scenarios were considered to propose modifications for handling real plant operation (flexibility. On the strength of plant complexity and large dimension, work methodology was split into two parts: initially, the whole plant was evaluated with traditional Pinch Analysis tools. Several opportunities were identified and modifications proposed. Modifications were segregated to represent small and independent portions of the original process. One of them was selected to be re-analyzed, considering two scenarios. Reduction of problem dimension allowed mathematical methodologies (formulation with decomposition, applying LP, MILP and NLP optimization methods to synthesize flexible networks to be applied, generating a feasible modification capable of fulfilling the proposed operational scenarios.
Energy Technology Data Exchange (ETDEWEB)
Masaki,
1976-04-15
The device described here serves to heat exhaust gases of internal combustion engines by heat exchange with hot gases and also, in cold engines, to raise the temperature of the fuel-air mixture drawn in by the engine. The device is installed next to the outlet opening of the engine. It consists of a burner to generate the hot gas, as well as a heat exchanger permitting heat supply to the exhaust gases and a hot-gas line leading to the intake line. Heating of the air is taken in leads to a better atomization of the mixture and thus to improved combustion. Heating of the exhaust gases improves afterburning. The burner generating the hot gas is shut off when the normal operational temperature of the engine is reached. The temperature is controlled by means of a temperature sensor installed in the device.
Eringen, A Cemal
2013-01-01
Continuum Physics: Volume 1 - Mathematics is a collection of papers that discusses certain selected mathematical methods used in the study of continuum physics. Papers in this collection deal with developments in mathematics in continuum physics and its applications such as, group theory functional analysis, theory of invariants, and stochastic processes. Part I explains tensor analysis, including the geometry of subspaces and the geometry of Finsler. Part II discusses group theory, which also covers lattices, morphisms, and crystallographic groups. Part III reviews the theory of invariants th
1993-01-01
This Strategic Plan was developed by the Federal Coordinating Council for Science, Engineering, and Technology (FCCSET) through its Committee on Education and Human Resources (CEHR), with representatives from 16 Federal agencies. Based on two years of coordinated interagency effort, the Plan confirms the Federal Government's commitment to ensuring the health and well-being of science, mathematics, engineering, and technology education at all levels and in all sectors (i.e., elementary and secondary, undergraduate, graduate, public understanding of science, and technology education). The Plan represents the Federal Government's efforts to develop a five-year planning framework and associated milestones that focus Federal planning and the resources of the participating agencies toward achieving the requisite or expected level of mathematics and science competence by all students. The priority framework outlines the strategic objectives, implementation priorities, and components for the Strategic Plan and serves as a road map for the Plan. The Plan endorses a broad range of ongoing activities, including continued Federal support for graduate education as the backbone of our country's research and development enterprise. The Plan also identifies three tiers of program activities with goals that address issues in science, mathematics, engineering, and technology education meriting special attention. Within each tier, individual agency programs play important and often unique roles that strengthen the aggregate portfolio. The three tiers are presented in descending order of priority: (1) reforming the formal education system; (2) expanding participation and access; and (3) enabling activities.
International Nuclear Information System (INIS)
Daghigh, Roonak; Shafieian, Abdellah
2016-01-01
Highlights: • The power output of the cycle is about 53 kW in the mass flow rate of 0.6 kg/s. • The output cooling water temperature of evaporator is 3.64 °C. • The absorption chiller has a coefficient of performance equal to 0.94. - Abstract: High temperature and mass flow rate of the exhaust gases of submarine diesel engines provide an appropriate potential for their thermal recovery. The current study introduces a combined cooling, heating and power system for thermal recovery of submarine diesel engines. The cooling system is composed of a mixed effect absorption chiller with two high and low pressure generators. The exhaust of the diesel engine is used in the high pressure generator, and the low pressure generator was divided into two parts. The required heat for the first and second compartments is supplied by the cooling water of the engine and condensation of the vapor generated in the high pressure generator, respectively. The power generation system is a Rankine cycle with an organic working fluid, which is considered a normal thermal system to supply hot water. The whole system is encoded based on mass stability, condensation and energy equations. The obtained findings showed that the maximum heat recovery for the power cycle occurs in exhaust gas mass ratio of 0.23–0.29 and working fluid mass flow rate of 0.45–0.57 kg/s. Further, for each specific mass ratio of exhaust gas, only a certain range of working fluid mass flow rate is used. In the refrigerant mass flow rate of 0.6 kg/s and exhaust gas mass ratio of 0.27, the power output of the cycle is 53 kW, which can also be achieved by simultaneous increase of refrigerant mass flow rate and exhaust gas mass ratio in a certain range of higher powers. In the next section, the overall distribution diagram of output water temperature of the thermal system is obtained according to the exhaust gas mass ratio in various mass flow rates, which can increase the potential of designing and controlling the
Optimum performance characteristics of a solar-driven Stirling heat engine system
International Nuclear Information System (INIS)
Liao, Tianjun; Lin, Jian
2015-01-01
Graphical abstract: T–S diagram of the SHE cycle. - Highlights: • Based on Lagrange multiplier method, the optimal performance are investigated. • The energy balance between the absorber and the hot side of Stirling heat engine is considered. • The effects of major parameters on the optimal performance are investigated. - Abstract: A solar-driven Stirling heat engine system composed of a Stirling heat engine, a solar collector, and a heat sink is presented, in which the radiation and convection heat losses of the solar collector, the heat-leak between the thermal absorber and heat sink, the regenerative losses of the Stirling heat engine, and the energy balance between the thermal absorber and the high isothermal process of the Stirling heat engine are taken into consideration. Based on the irreversible thermodynamics and Lagrange multiplier method, the maximum power output and the corresponding optimal efficiency of the system are determined and the absorber temperature that maximizes the optimal system efficiency is calculated numerically. The influences of some system parameters such as the concentrating ratio, the volume ratio during the regenerative processes and irreversibilities of heat exchange processes on the optimal efficiency are analyzed in details. The results obtained here may provide a new idea to design practical solar-driven Stirling heat engine system
Mathematical modelling of heat absorption capacity of containment spray system in a 700 MWe PHWR
International Nuclear Information System (INIS)
Kota, Sampath Bharadwaj; Ali, Seik Mansoor; Balasubramaniyan, V.
2015-01-01
This paper presents a mathematical model for estimating the heat removal by containment spray system in the post Loss of Coolant Accident (LOCA) environment. The procedure involves firstly, the calculation of heat removal rates by droplets of spray dispersed in the air-steam mixture by an appropriate direct contact condensation model accounting for the presence of non-condensable gas (air). Parametric influence of droplet size, ambient pressure and temperature on heat flux is brought out. It was found that the heat flux is inversely proportional to the ambient pressure and diameter. A spray module was subsequently developed and incorporated into an in-house containment thermal hydraulics code. The pressure and temperature transients in a 700 MWe PHWR containment building following a Large Break LOCA was obtained using this code. The efficacy of the spray in condensing the steam is shown by comparing the transients with and without the operation of spray system. Parametric studies are also conducted with respect to droplet size and flow rate of water droplet spray. The details of the investigation are presented and discussed in this paper. (author)
International Nuclear Information System (INIS)
Debeljkovic, D.Lj.; Stevic, D.Z.; Simeunovic, G.V.; Misic, M.A.
2015-01-01
The heat exchangers are frequently used as constructive elements in various plants and their dynamics is very important. Their operation is usually controlled by manipulating inlet fluid temperatures or mass flow rates. On the basis of the accepted and critically clarified assumptions, a linearized mathematical model of the cross-flow heat exchanger has been derived, taking into account the wall dynamics. The model is based on the fundamental law of energy conservation, covers all heat accumulation storages in the process, and leads to the set of partial differential equations (PDE), which solution is not possible in closed form. In order to overcome the solutions difficulties in this paper are analyzed different methods for modeling the heat exchanger: approach based on Laplace transformation, approximation of partial differential equations based on finite differences, the method of physical discretization and the transport approach. Specifying the input temperatures and output variables, under the constant initial conditions, the step transient responses have been simulated and presented in graphic form in order to compare these results for the four characteristic methods considered in this paper, and analyze its practical significance. (author)
Mathematical modeling of the complete thermodynamic cycle of a new Atkinson cycle gas engine
International Nuclear Information System (INIS)
Shojaeefard, Mohammad Hassan; Keshavarz, Mojtaba
2015-01-01
The Atkinson cycle provides the potential to increase the efficiency of SI engines using overexpansion concept. This also will suggest decrease in CO_2 generation by internal combustion engine. In this study a mathematical modeling of complete thermodynamic cycle of a new two-stroke Atkinson cycle SI engine will be presented. The mathematical modeling is carried out using two-zone combustion analysis in order to make the model predict exhaust emission so that its values could be compared with the values of conventional SI engine. The model also is validated against experimental tests in that increase in efficiency is achieved compared to conventional SI engines. - Highlights: • The complete cycle model for the rotary Atkinson engine was developed. • Comparing the results with experimental data shows good model validity. • The model needs further improvement for the scavenging phase. • There is 5% increment in thermal efficiency with new engine compared to conventional SI engines.
Chiel, Hillel J.; McManus, Jeffrey M.; Shaw, Kendrick M.
2010-01-01
We describe the development of a course to teach modeling and mathematical analysis skills to students of biology and to teach biology to students with strong backgrounds in mathematics, physics, or engineering. The two groups of students have different ways of learning material and often have strong negative feelings toward the area of knowledge…
Nakakoji, Yoshitaka; Wilson, Rachel
2018-01-01
Transfer of mathematical learning to science is seen as critical to the development of education and industrial societies, yet it is rarely interrogated in applied research. We present here research looking for evidence of transfer from university mathematics learning in semester one to second semester sciences/engineering courses (n = 1125). A…
Dubetz, Terry A.; Wilson, Jo Ann
2013-01-01
Girls in Engineering, Mathematics and Science (GEMS) is a science and math outreach program for middle-school female students. The program was developed to encourage interest in math and science in female students at an early age. Increased scientific familiarity may encourage girls to consider careers in science and mathematics and will also help…
Matzakos, Nikolaos M.; Kalogiannakis, Michail
2018-01-01
An online support distance-learning program in Mathematics was developed to aid first year engineering students for their transition from the secondary to the tertiary education in order to reinforce deficiencies they may have in mathematical knowledge. The aim of the present study is to examine, firstly, to what extent the attendance of such a…
Piston surface heat transfer during combustion in large marine diesel engines
DEFF Research Database (Denmark)
Jensen, Michael Vincent; Walther, Jens Honore
2010-01-01
In the design process of large marine diesel engines information on the maximum heat load on the piston surface experienced during the engine cycle is an important parameter. The peak heat load occurs during combustion when hot combustion products impinge on the piston surface. Although the maximum...... heat load is only present for a short time of the total engine cycle, it is a severe thermal load on the piston surface. At the same time, cooling of the piston crown is generally more complicated than cooling of the other components of the combustion chamber. This can occasionally cause problems...... with burning off piston surface material. In this work the peak heat load on the piston surface of large marine diesel engines during combustion was investigated. Measurements of the instantaneous surface temperature and surface heat flux on pistons in large marine engines are difficult due to expensive...
Directory of Open Access Journals (Sweden)
V. S. Kudryashov
2017-01-01
Full Text Available The article is devoted to the development of the algorithm of the heating phase control of a rubber compound for CJSC “Voronezh tyre plant”. The algorithm is designed for implementation on basis of controller Siemens S-300 to control the RS-270 mixer. To compile the algorithm a systematic analysis of the heating process has been performed as a control object, also the mathematical model of the heating phase has been developed on the basis of the heat balance equation, which describes the process of heating of a heat-transfer agent in the heat exchanger and further heating of the mixture in the mixer. The dynamic characteristics of temperature of the heat exchanger and the rubber mixer have been obtained. Taking into account the complexity and nonlinearity of the control object – a rubber mixer, as well as the availability of methods and great experience in managing this machine in an industrial environment, the algorithm has been implemented using the Pontryagin maximum principle. The optimization problem is reduced to determining the optimal control (heating steam supply and the optimal path of the object’s output coordinates (the temperature of the mixture which ensure the least flow of steam while heating a rubber compound in a limited time. To do this, the mathematical model of the heating phase has been written in matrix form. Coefficients matrices for each state of the control, control and disturbance vectors have been created, the Hamilton function has been obtained and time switching points have been found for constructing an optimal control and escape path of the object. Analysis of the model experiments and practical research results in the process of programming of the controller have showed a decrease in the heating steam consumption by 24.4% during the heating phase of the rubber compound.
Campbell, P. C.; Hawbolt, E. B.; Brimacombe, J. K.
1991-11-01
The goal of this study was to develop a mathematical model which incorporates heat flow, phase transformation kinetics, and property-structure-composition relationships to predict the mechanical properties of steel rod being control cooled under industrial conditions. Thus, the principles of microstructural engineering have been brought to bear on this interdisciplinary problem by combining computer modeling with laboratory measurements of heat flow, austenite decomposition kinetics, microstructure and mechanical properties, and industrial trials to determine heat transfer and obtain rod samples under known conditions. Owing to the length and diversity of the study, it is reported in three parts,[8191]the first of which is concerned with the heat flow measurements. A relatively simple and reliable technique, involving a preheated steel rod instrumented with a thermocouple secured at its centerline, has been devised to determine the cooling rate in different regions of the moving bed of rod loops on an operating Stelmor line. The measured thermal response of the rod has been analyzed by two transient conduction models (lumped and distributed parameter, respectively) to yield overall heat-transfer coefficients for radiation and convection. The adequacy of the technique has been checked by cooling instrumented rods under well-defined, air crossflow conditions in the laboratory and comparing measured heat-transfer coefficients to values predicted from well-established equations. The industrial thermal measurements have permitted the characterization of a coefficient to account for radiative interaction among adjacent rod loops near the edge and at the center of the bed.
Nguyen, H. L.; Addy, H. E.; Bond, T. H.; Lee, C. M.; Chun, K. S.
1987-01-01
A computer simulation which models engine performance of the Direct Injection Stratified Charge (DISC) rotary engines was used to study the effect of variations in engine design and operating parameters on engine performance and efficiency of an Outboard Marine Corporation (OMC) experimental rotary combustion engine. Engine pressure data were used in a heat release analysis to study the effects of heat transfer, leakage, and crevice flows. Predicted engine data were compared with experimental test data over a range of engine speeds and loads. An examination of methods to improve the performance of the rotary engine using advanced heat engine concepts such as faster combustion, reduced leakage, and turbocharging is also presented.
Directory of Open Access Journals (Sweden)
Toshihiro Ashino
2012-12-01
Full Text Available Many relationships between parameters and physical properties in materials science and engineering are represented as mathematical expressions, such as empirical equations and regression expressions. Some materials databases handle such information with indirect methods: as a table of sets of parameters, as a list of statements of programming languages, and other ways. There is no standardized way to represent mathematical relationships, and that makes it difficult to exchange, process, and display such information. The AIST (National Institute of Advanced Industrial Science and Technology in Japan thermophysical property database manages sets of parameter values for expressions and Fortran statements that represent relationships between physical parameters, e.g., temperature, pressure, etc. and thermophysical properties. However, in this method, it is not easy to add new parameters, to process expressions, and exchange information with other software tools. In this paper, we describe the current implementation of representing mathematical knowledge in the AIST thermophysical property database, and we also discuss its problems, sample implementations, and definitions of the OpenMath content dictionary for materials science and engineering.
Moscardini, Alfredo
1994-01-01
As the role of the modern engineer is markedly different from that of even a decade ago, the theme of engineering mathematics educa tion (EME) is an important one. The need for mathematical model ling (MM) courses and consideration of the educational impact of computer-based technology environments merit special attention. This book contains the proceeding of the NATO Advanced Research Workshop held on this theme in July 1993. We have left the industrial age behind and have entered the in formation age. Computers and other emerging technologies are penetrating society in depth and gaining a strong influence in de termining how in future society will be organised, while the rapid change of information requires a more qualified work force. This work force is vital to high technology and economic competitive ness in many industrialised countries throughout the world. Within this framework, the quality of EME has become an issue. It is expected that the content of mathematics courses taught in schools o...
Directory of Open Access Journals (Sweden)
Bondarenko V.I.
2015-03-01
Full Text Available The generic mathematical model and computational algorithm considering hydrodynamics, heat and mass transfer processes during casting and forming steel ingots and castings are offered. Usage domains for turbulent, convective and non-convective models are determined depending on ingot geometry and thermal overheating of the poured melt. The expert system is developed, enabling to choose a mathematical model depending on the physical statement of a problem.
On the importance of specific heats as regards efficiency increases for highly dilute IC engines
International Nuclear Information System (INIS)
Caton, Jerald A.
2014-01-01
Highlights: • Importance of specific heats towards increasing engine efficiency was quantified. • Decreases of specific heats contribute 3.5–6.3% (abs) to the efficiency. • Dilute engines benefit from decreases of specific heats due to lower temperatures. - Abstract: Engineering and scientific efforts continue with the development of advanced, IC engines using highly dilute mixtures, and relatively high compression ratios. Such engines are known to provide opportunities for low emissions as well as high efficiencies. The main features of these engines include higher compression ratios, lean operation, use of EGR, and shorter burn durations. First, this study reviews the quantitative contributions of each of these features as determined by an engine cycle simulation. Second, this study provides the quantitative contributions to the increased efficiency in terms of fundamental thermodynamic considerations. An automotive engine operated at 2000 rpm was selected for this study. For the conditions examined, the net indicated thermal efficiency increased from 37.0% (conventional engine) to 53.9% (high efficiency engine) – for an incremental increase of 16.9% (absolute). The contribution of increases of the ratio of specific heats towards the final thermal efficiency is quantified. This aspect has been well known, but has not been quantified for actual engines. For the various conditions examined, 21–35% of the total efficiency improvement was estimated to be due to the increase of the ratio of specific heats
Stein, Sherman K
2010-01-01
Anyone can appreciate the beauty, depth, and vitality of mathematics with the help of this highly readable text, specially developed from a college course designed to appeal to students in a variety of fields. Readers with little mathematical background are exposed to a broad range of subjects chosen from number theory, topology, set theory, geometry, algebra, and analysis. Starting with a survey of questions on weight, the text discusses the primes, the fundamental theorem of arithmetic, rationals and irrationals, tiling, tiling and electricity, probability, infinite sets, and many other topi
International Nuclear Information System (INIS)
Sheng, Shiqi; Tu, Z C
2013-01-01
A unified χ-criterion for heat devices (including heat engines and refrigerators), which is defined as the product of the energy conversion efficiency and the heat absorbed per unit time by the working substance (de Tomás et al 2012 Phys. Rev. E 85 010104), is optimized for tight-coupling heat engines and refrigerators operating between two heat baths at temperatures T c and T h ( > T c ). By taking a new convention on the thermodynamic flux related to the heat transfer between two baths, we find that for a refrigerator tightly and symmetrically coupled with two heat baths, the coefficient of performance (i.e., the energy conversion efficiency of refrigerators) at maximum χ asymptotically approaches √(ε C ) when the relative temperature difference between two heat baths ε C -1 ≡(T h -T c )/T c is sufficiently small. Correspondingly, the efficiency at maximum χ (equivalent to maximum power) for a heat engine tightly and symmetrically coupled with two heat baths is proved to be η C /2+η C 2 /8 up to the second order term of η C ≡ (T h − T c )/T h , which reverts to the universal efficiency at maximum power for tight-coupling heat engines operating between two heat baths at small temperature difference in the presence of left–right symmetry (Esposito et al 2009 Phys. Rev. Lett. 102 130602). (fast track communication)
Stirling engine or heat pump having an improved seal
White, Maurice A.; Riggle, Peter; Emigh, Stuart G.
1985-01-01
A Stirling Engine or Heat Pump having two relatively movable machine elements for power transmission purposes includes a hermetic seal bellows interposed between the elements for separating a working gas from a pressure compensating liquid that balances pressure across the bellows to reduce bellows stress and to assure long bellows life. The volume of pressure compensating liquid displaced due to relative movement between the machine elements is minimized by enclosing the compensating liquid within a region exposed to portions of both machine elements at one axial end of a slidable interface presented between them by a clearance seal having an effective diameter of the seal bellows. Pressure equalization across the bellows is achieved by a separate hermetically sealed compensator including a movable enclosed bellows. The interior of the compensator bellows is in communication with one side of the seal bellows, and its exterior is in communication with the remaining side of the seal bellows. A buffer gas or additional liquid region can be provided at the remaining axial end of the clearnace seal, along with valved arrangements for makeup of liquid leakage through the clearance seal.
Possible directions for using bran in heat-power engineering
Directory of Open Access Journals (Sweden)
Gaydabrus Maria
2017-01-01
Full Text Available In connection with the necessity of providing of ecofriendlyness of energy the researches sent to the increase of stake of biomass in fuel and energy balance are actual direction of science and technique. The aim of work is put the study of heating engineering properties of bran and research of possibility of briquetting as it applies to the power use in the stratified fire-box devices. Research methods included standard methodologies of ISO and physical experiment. It is shown as a result of research that bran on the warmth of combustion is comparable with brown coals, but has a less ash-content considerably. However shallow factious composition of bran and caking in the process of ashing will result in high operating costs at their incineration in a natural kind. The variant of the power use of bran is considered as the preforms got the thermal pressing, and the optimal temperature of pressing, equal 150°C. On the example of pressing of shell of cedar nuts possibility of the use of bran is shown as connective, is set here.
Reversible and irreversible heat engine and refrigerator cycles
Leff, Harvey S.
2018-05-01
Although no reversible thermodynamic cycles exist in nature, nearly all cycles covered in textbooks are reversible. This is a review, clarification, and extension of results and concepts for quasistatic, reversible and irreversible processes and cycles, intended primarily for teachers and students. Distinctions between the latter process types are explained, with emphasis on clockwise (CW) and counterclockwise (CCW) cycles. Specific examples of each are examined, including Carnot, Kelvin and Stirling cycles. For the Stirling cycle, potentially useful task-specific efficiency measures are proposed and illustrated. Whether a cycle behaves as a traditional refrigerator or heat engine can depend on whether it is reversible or irreversible. Reversible and irreversible-quasistatic CW cycles both satisfy Carnot's inequality for thermal efficiency, η ≤ η C a r n o t . Irreversible CCW cycles with two reservoirs satisfy the coefficient of performance inequality K ≤ K C a r n o t . However, an arbitrary reversible cycle satisfies K ≥ K C a r n o t when compared with a reversible Carnot cycle operating between its maximum and minimum temperatures, a potentially counterintuitive result.
Cascade fuzzy control for gas engine driven heat pump
International Nuclear Information System (INIS)
Li Shuze; Zhang Wugao; Zhang Rongrong; Lv Dexu; Huang Zhen
2005-01-01
In addition to absorption chillers, today's gas cooling technology includes gas engine driven heat pump systems (GEHP) in a range of capacities and temperature capacities suitable for most commercial air conditioning and refrigeration applications. Much is expected from GEHPs as a product that would help satisfy the air conditioning system demand from medium and small sized buildings, restrict electric power demand peaks in summer and save energy in general. This article describes a kind of control strategy for a GEHP, a cascade fuzzy control. GEHPs have large and varying time constants and their dynamic modeling cannot be easily achieved. A cascade control strategy is effective for systems that have large time constants and disturbances, and a fuzzy control strategy is fit for a system that lacks an accurate model. This cascade fuzzy control structure brings together the best merits of fuzzy control and cascade control structures. The performance of the cascade fuzzy control is compared to that of a cascade PI (proportional and integral) control strategy, and it is shown by example that the cascade fuzzy control strategy gives a better performance, reduced reaction time and smaller overshoot temperature
Gustof, P.; Hornik, A.
2016-09-01
In the paper, numeric calculations of thermal stresses of the piston in a turbocharged Diesel engine in the initial phase of its work were carried out based on experimental studies and the data resulting from them. The calculations were made using a geometrical model of the piston in a five-cylinder turbocharged Diesel engine with a capacity of about 2300 cm3, with a direct fuel injection to the combustion chamber and a power rating of 85 kW. In order to determine the thermal stress, application of own mathematical models of the heat flow in characteristic surfaces of the piston was required to show real processes occurring on the surface of the analysed component. The calculations were performed using a Geostar COSMOS/M program module. A three-dimensional geometric model of the piston was created in this program based on a real component, in order to enable the calculations and analysis of thermal stresses during non-stationary heat flow. Modelling of the thermal stresses of the piston for the engine speed n=4250 min-1 and engine load λ=1.69 was carried out.
International Nuclear Information System (INIS)
Demazure, M.
1988-01-01
The 1988 progress report of the Mathematics center (Polytechnic School, France), is presented. The Center is composed of different research teams: analysis, Riemann geometry, group theory, formal calculus and algorithm geometry, dynamical systems, topology and singularity. For each team, the members, the research topics, the national and international cooperations, are given. The papers concerning the investigations carried out in 1988, are listed [fr
Povinelli, Louis A.
2001-01-01
A thermodynamic cycle analysis of the effect of sensible heat release on the relative performance of pulse detonation and gas turbine engines is presented. Dissociation losses in the PDE (Pulse Detonation Engine) are found to cause a substantial decrease in engine performance parameters.
Directory of Open Access Journals (Sweden)
Christoph J.W. Kirmse
2016-06-01
Full Text Available The Up-THERM heat converter is an unsteady, two-phase thermofluidic oscillator that employs an organic working fluid, which is currently being considered as a prime-mover in small- to medium-scale combined heat and power (CHP applications. In this paper, the Up-THERM heat converter is compared to a basic (sub-critical, non-regenerative organic Rankine cycle (ORC heat engine with respect to their power outputs, thermal efficiencies and exergy efficiencies, as well as their capital and specific costs. The study focuses on a pre-specified Up-THERM design in a selected application, a heat-source temperature range from 210 °C to 500 °C and five different working fluids (three n-alkanes and two refrigerants. A modeling methodology is developed that allows the above thermo-economic performance indicators to be estimated for the two power-generation systems. For the chosen applications, the power output of the ORC engine is generally higher than that of the Up-THERM heat converter. However, the capital costs of the Up-THERM heat converter are lower than those of the ORC engine. Although the specific costs (£/kW of the ORC engine are lower than those of the Up-THERM converter at low heat-source temperatures, the two systems become progressively comparable at higher temperatures, with the Up-THERM heat converter attaining a considerably lower specific cost at the highest heat-source temperatures considered.
The Gender-Equality Paradox in Science, Technology, Engineering, and Mathematics Education.
Stoet, Gijsbert; Geary, David C
2018-04-01
The underrepresentation of girls and women in science, technology, engineering, and mathematics (STEM) fields is a continual concern for social scientists and policymakers. Using an international database on adolescent achievement in science, mathematics, and reading ( N = 472,242), we showed that girls performed similarly to or better than boys in science in two of every three countries, and in nearly all countries, more girls appeared capable of college-level STEM study than had enrolled. Paradoxically, the sex differences in the magnitude of relative academic strengths and pursuit of STEM degrees rose with increases in national gender equality. The gap between boys' science achievement and girls' reading achievement relative to their mean academic performance was near universal. These sex differences in academic strengths and attitudes toward science correlated with the STEM graduation gap. A mediation analysis suggested that life-quality pressures in less gender-equal countries promote girls' and women's engagement with STEM subjects.
Inverted Classroom by Topic - A Study in Mathematics for Electrical Engineering Students
Directory of Open Access Journals (Sweden)
Isabel Braun
2014-06-01
Full Text Available The inverted classroom is a teaching model, where the students prepare for classroom by watching video lectures. The classroom time is then dedicated to individual practice. We evaluated a mathematics course for electrical engineering students throughout three semesters, where 20% of the topics were taught using the inverted classroom model. The aim was to find out whether the model can help to better address groups with large differences in prior knowledge in mathematics. We report mainly positive feedback from the students, although the opinions vary greatly between the groups. The students appreciate the increased amount of practice in the classroom as well as the possibility to learn at their own pace. Exam performance remained constant in the topics taught using the inverted classroom compared to previous semesters. The exam performance of weaker students also remained constant.
First-year engineering students' use of their mathematics textbook - opportunities and constraints
Randahl, Mira
2012-09-01
The role of the mathematics textbook at tertiary level has received limited exposure in previous research although it is likely that students work individually and that some of this work depends on the use of the textbook. The aim of this study was to investigate the process of approaching the textbook from epistemological, cognitive, and didactical perspectives. The focus was on identifying and discussing the opportunities and constraints in the process. The study was an explorative case study and the participants were first-year engineering students taking a basic calculus course. The data were collected through questionnaires, observations, and interviews. Results showed that the textbook was used to a very low degree and mainly perceived as a source of tasks. Different opportunities and constraints are pointed out and some didactical implications are suggested. The results and discussion indicate that a need for greater awareness about the use of mathematical textbooks in meaningful ways at tertiary level.
Chaskalovic, Joël
2014-01-01
This self-tutorial offers a concise yet thorough introduction into the mathematical analysis of approximation methods for partial differential equation. A particular emphasis is put on finite element methods. The unique approach first summarizes and outlines the finite-element mathematics in general and then, in the second and major part, formulates problem examples that clearly demonstrate the techniques of functional analysis via numerous and diverse exercises. The solutions of the problems are given directly afterwards. Using this approach, the author motivates and encourages the reader to actively acquire the knowledge of finite- element methods instead of passively absorbing the material, as in most standard textbooks. This English edition is based on the Finite Element Methods for Engineering Sciences by Joel Chaskalovic
International Nuclear Information System (INIS)
Zhang, R.R.; Lu, X.S.; Li, S.Z.; Lin, W.S.; Gu, A.Z.
2005-01-01
In this study, the heating performance of a gas engine driven air to water heat pump was analyzed using a steady state model. The thermodynamic model of a natural gas engine is identified by the experimental data and the compressor model is created by several empirical equations. The heat exchanger models are developed by the theory of heat balance. The system model is validated by comparing the experimental and simulation data, which shows good agreement. To understand the heating characteristic in detail, the performance of the system is analyzed in a wide range of operating conditions, and especially the effect of engine waste heat on the heating performance is discussed. The results show that engine waste heat can provide about 1/3 of the total heating capacity in this gas engine driven air to water heat pump. The performance of the engine, heat pump and integral system are analyzed under variations of engine speed and ambient temperature. It shows that engine speed has remarkable effects on both the engine and heat pump, but ambient temperature has little influence on the engine's performance. The system and component performances in variable speed operating conditions is also discussed at the end of the paper
Energy Technology Data Exchange (ETDEWEB)
Katz, M
1984-01-01
The dictionary lists technical terms of the fields of combustion engineering and heating engineering. The heating engineering part was kept as short as possible; only those terms are listed, that are directly or indirectly related to combustion engineering. Contents: Definitions, standard nomenclature, burner systems, treatment systems, burner components, dictionary, SI-units, drawings with translations. 26 figs.
Optimization of the dynamic and thermal performance of a resonant micro heat engine
International Nuclear Information System (INIS)
Bardaweel, H K; Richards, R F; Richards, C D; Anderson, M J
2008-01-01
The dynamic behavior of a flexing membrane micro heat engine is presented. The micro heat engine consists of a cavity filled with a saturated, two-phase working fluid bounded on the top by a flexible expander membrane and on the bottom by a stiff evaporator membrane. A lumped parameter model is developed to simulate the dynamic behavior of the micro heat engine. First, the model is validated against experimental data. Then, the model is used to investigate the effect of the duration of the heat addition process, the mass of the expander membrane and the thermal storage or thermal inertia associated with the engine cavity on the dynamic behavior of the micro engine. The results show the optimal duration for the heat addition process to be less than 10% of the engine cycle period. Increasing the mass of the flexible expander membrane is shown to reduce the resonant frequency of the engine to 130 Hz. Operating the engine at resonance leads to increased power output. The thermal storage or thermal inertia associated with the engine cavity is shown to have a strong effect on engine performance
Verta, Antonella; Schena, Emiliano; Silvestri, Sergio
2010-06-01
The control of thermo-hygrometric conditions of gas delivered in neonatal mechanical ventilation appears to be a particularly difficult task, mainly due to the vast number of parameters to be monitored and the control strategies of heated humidifiers to be adopted. In the present paper, we describe the heat and fluid exchange occurring in a heated humidifier in mathematical terms; we analyze the sensitivity of the relative humidity of outlet gas as a function of thermo-hygrometric and fluid-dynamic parameters of delivered gas; we propose a control strategy that will enable the stability of outlet gas thermo-hygrometric conditions. The mathematical model is represented by a hyper-surface containing the functional relations between the input variables, which must be measured, and the output variables, which have to remain constant. Model sensitivity analysis shows that heated humidifier efficacy and stability of outlet gas thermo-hygrometric conditions are principally influenced by four parameters: liquid surface temperature, gas flow rate, inlet gas temperature and inlet gas relative humidity. The theoretical model has been experimentally validated in typical working conditions of neonatal applications. The control strategy has been implemented by a minimal measurement system composed of three thermometers, a humidity sensor, and a flow rate sensor, and based on the theoretical model. Outlet relative humidity, contained in the range 90+/-4% and 94+/-4%, corresponding with temperature variations in the range 28+/-2 degrees C and 38+/-2 degrees C respectively, has been obtained in the whole flow rate range typical of neonatal ventilation from 1 to 10 L/min. We conclude that in order to obtain the stability of the thermo-hygrometric conditions of the delivered gas mixture: (a) a control strategy with a more complex measurement system must be implemented (i.e. providing more input variables); (b) and the gas may also need to be pre-warmed before entering the humidifying
Wheels, Cranks, and Cams: An Animated Spreadsheet-Based Mathematical Model of a Four-Stroke Engine.
Callender, J. T.; Jackson, R.
1998-01-01
Analyzes the mathematics of rotational and translational motion and how one can influence the other in the context of cams and cranks. Describes how the individual components can be brought together to simulate a four-stroke engine and how the engine animates again using the same simple macro. (Author/ASK)
2016-01-08
Actuarial Science Taylor, Triniti Lanier Alcorn State University Animal Science Tchounwou, Hervey Madison Central Jackson State University Computer...for Public Release; Distribution Unlimited Final Report: Jackson State University (JSU)’s Center of Excellence in Science , Technology, Engineering...Final Report: Jackson State University (JSU)’s Center of Excellence in Science , Technology, Engineering, and Mathematics Education (CESTEME) Report
Directory of Open Access Journals (Sweden)
V. V. Leonov
2014-01-01
Full Text Available When designing large-sized mirror concentrating systems (MCS for high-temperature solar power plants, one must have at disposal reasonably reliable and economical methods and tools, making it possible to analyze its characteristics, to predict them depending on the operation conditions and accordingly to choose the most suitable system for the solution of particular task.Experimental determination of MCS characteristics requires complicated and expensive experimentation, having significant limitations on interpretation of the results, as well as limitations imposed due to the size of the structure. Therefore it is of particular interest to develop a mathematical model capable of estimating power characteristics of MCS considering the influence of operating conditions, design features, roughness and other surface defects.For efficient solution of the tasks the model must ensure simulation of solar radiant flux as well as simulation of geometrical and optical characteristics of reflection surface and their interaction. In this connection a statistical mathematical model of radiation heat exchange based on use of Monte Carlo methods and Finite Element Method was developed and realized in the software complex, making it possible to determine main characteristics of the MCS.In this paper the main attention is given to definition of MCS radiation characteristics with account for deep reflecting surface defects (cavities, craters. Deep cavities are not typical for MCS, but their occurrence is possible during operation as a result of erosion or any physical damage. For example, for space technology it is primarily micrometeorite erosion.
A review of heat transfer in human tooth--experimental characterization and mathematical modeling.
Lin, Min; Xu, Feng; Lu, Tian Jian; Bai, Bo Feng
2010-06-01
With rapid advances in modern dentistry, high-energy output instruments (e.g., dental lasers and light polymerizing units) are increasingly employed in dental surgery for applications such as laser assisted tooth ablation, bleaching, hypersensitivity treatment and polymerization of dental restorative materials. Extreme high temperature occurs within the tooth during these treatments, which may induce tooth thermal pain (TTP) sensation. Despite the wide application of these dental treatments, the underlying mechanisms are far from clear. Therefore, there is an urgent need to better understand heat transfer (HT) process in tooth, thermally induced damage of tooth, and the corresponding TTP. This will enhance the design and optimization of clinical treatment strategies. This paper presents the state-of-the-art of the current understanding on HT in tooth, with both experimental study and mathematical modeling reviewed. Limitations of the current experimental and mathematical methodologies are discussed and potential solutions are suggested. Interpretation of TTP in terms of thermally stimulated dentinal fluid flow is also discussed. Copyright (c) 2010 Academy of Dental Materials. All rights reserved.
International Nuclear Information System (INIS)
Torregrosa, A.J.; Bermúdez, V.; Olmeda, P.; Fygueroa, O.
2012-01-01
Higlights: ► We measured in-cylinder wall heat fluxes. ► We examine the effects of different engine parameters. ► Increasing air mass flow increase heat fluxes. ► The effect of engine speed can be masked by the effect of volumetric efficiency. ► Differences among the different walls have been found. - Abstract: The main goal of this work is to validate an innovative experimental facility and to establish a methodology to evaluate the influence of some of the engine parameters on local engine heat transfer behaviour under motored steady-state conditions. Instantaneous temperature measurements have been performed in order to estimate heat fluxes on a modified Diesel single cylinder combustion chamber. This study was divided into two main parts. The first one was the design and setting on of an experimental bench to reproduce Diesel conditions and perform local-instantaneous temperature measurements along the walls of the combustion chamber by means of fast response thermocouples. The second one was the development of a procedure for temperature signal treatment and local heat flux calculation based on one-dimensional Fourier analysis. A thermodynamic diagnosis model has been employed to characterise the modified engine with the new designed chamber. As a result of the measured data coherent findings have been obtained in order to understand local behaviour of heat transfer in an internal combustion engine, and the influence of engine parameters on local instantaneous temperature and heat flux, have been analysed.
Evaluation of an Integrated Curriculum in Physics, Mathematics, Engineering, and Chemistry
Beichner, Robert
1997-04-01
An experimental, student centered, introductory curriculum called IMPEC (for Integrated Mathematics, Physics, Engineering, and Chemistry curriculum) is in its third year of pilot-testing at NCSU. The curriculum is taught by a multidisciplinary team of professors using a combination of traditional lecturing and alternative instructional methods including cooperative learning, activity-based class sessions, and extensive use of computer modeling, simulations, and the world wide web. This talk will discuss the research basis for our design and implementation of the curriculum, the qualitative and quantitative methods we have been using to assess its effectiveness, and the educational outcomes we have noted so far.
Post secondary project-based learning in science, technology, engineering and mathematics
Ralph, Rachel A.
2016-01-01
Project-based learning (PjBL - to distinguish from problem-based learning - PBL) has become a recurrent practice in K-12 classroom environments. As PjBL has become prominent in K-12 classrooms, it has also surfaced in post-secondary institutions. The purpose of this paper is to examine the research that has studied a variety of science, technology, engineering and mathematic subjects using PjBL in post-secondary classrooms. Eleven articles (including qualitative, quantitative and mixed metho...
Quantum Stirling heat engine and refrigerator with single and coupled spin systems
Huang, Xiao-Li; Niu, Xin-Ya; Xiu, Xiao-Ming; Yi, Xue-Xi
2014-02-01
We study the reversible quantum Stirling cycle with a single spin or two coupled spins as the working substance. With the single spin as the working substance, we find that under certain conditions the reversed cycle of a heat engine is NOT a refrigerator, this feature holds true for a Stirling heat engine with an ion trapped in a shallow potential as its working substance. The efficiency of quantum Stirling heat engine can be higher than the efficiency of the Carnot engine, but the performance coefficient of the quantum Stirling refrigerator is always lower than its classical counterpart. With two coupled spins as the working substance, we find that a heat engine can turn to a refrigerator due to the increasing of the coupling constant, this can be explained by the properties of the isothermal line in the magnetic field-entropy plane.
Energy Technology Data Exchange (ETDEWEB)
1990-07-01
The purpose of the Ceramic Technology for Advanced Heat Engines (CTAHE) Project is the development of an industrial technology base capable of providing reliable and cost-effective high temperature ceramic components for application in advanced heat engines. There is a deliberate emphasis on industrial'' in the purpose statement. The project is intended to support the US ceramic and engine industries by providing the needed ceramic materials technology. The heat engine programs have goals of component development and proof-of-concept. The CTAHE Project is aimed at developing generic basic ceramic technology and does not involve specific engine designs and components. The materials research and development efforts in the CTAHE Project are focused on the needs and general requirements of the advanced gas turbine and low heat rejection diesel engines. The CTAHE Project supports the DOE Office of Transportation Systems' heat engine programs, Advanced Turbine Technology Applications (ATTAP) and Heavy Duty Transport (HDT) by providing the basic technology required for development of reliable and cost-effective ceramic components. The heat engine programs provide the iterative component design, fabrication, and test development logic. 103 refs., 18 figs., 11 tabs.
Heat transfer comparison between methane and hydrogen in a spark ignited engine
Energy Technology Data Exchange (ETDEWEB)
Sierens, Roger; Demuynck, Joachim; Paepe, Michel de; Verhelst, Sebastian [Ghent Univ. (Belgium)
2010-07-01
Hydrogen is one of the alternative fuels which are being investigated at Ghent University. NO{sub x} emissions will occur at high engine loads and they are a constraint for power and efficiency optimization. The formation of NO{sub x} emissions is temperature dependent. Consequently, the heat transfer from the burning gases to the cylinder walls has to be accurately modelled if precise computer calculations of the emissions are wanted. Several engine heat transfer models exist but they have been cited to be inaccurate for hydrogen. We have measured the heat flux in a spark ignited engine with a commercially available heat flux sensor. This paper investigates the difference between the heat transfer of hydrogen and a fossil fuel, in this case methane. Measurements with the same indicated power output are compared and the effect of the heat loss on the indicated efficiency is investigated. The power output of hydrogen combustion is lowered by burning lean in contrast to using a throttle in the case of methane. Although the peak in the heat flux of hydrogen is 3 times higher compared to methane for a high engine power output, the indicated efficiency is only 3% lower. The heat loss for hydrogen at a low engine load is smaller than that of methane which results in a higher indicated efficiency. The richness of the hydrogen-air mixture has a great influence on the heat transfer process in contrast to the in-cylinder mass in the case of methane. (orig.)
Malone-brayton cycle engine/heat pump
Gilmour, Thomas A.
1994-07-01
A machine, such as a heat pump, and having an all liquid heat exchange fluid, operates over a more nearly ideal thermodynamic cycle by adjustment of the proportionality of the volumetric capacities of a compressor and an expander to approximate the proportionality of the densities of the liquid heat exchange fluid at the chosen working pressures. Preferred forms of a unit including both the compressor and the expander on a common shaft employs difference in axial lengths of rotary pumps of the gear or vane type to achieve the adjustment of volumetric capacity. Adjustment of the heat pump system for differing heat sink conditions preferably employs variable compression ratio pumps.
News from the Library: Springer e-books in Engineering and Mathematics - now at your desktop!
CERN Library
2013-01-01
Users obviously expect library collections to be shaped to meet their information needs. Today, online systems have replaced the good old "Book Suggestion Register" to help readers provide libraries with input. Moreover, e-books lend themselves by their nature to a trial period, whereby the needs and the potential usage of collections can be effectively measured. In this sense, the trial of Springer e-books on engineering done in October-November last year was extremely fruitful because it showed the interest of the community and provided us with essential feedback. Following that trial, the Library now provides access to a collection of Springer e-books on Engineering published in 2012 and 2013 and also on Mathematics (2010-2013). These collections complement the Springer Physics and Astronomy and "Lecture Notes in Physics" e-books series. As usual, your feedback is most welcome! Please contact us by e-mail.
Building a Network to Support Girls and Women in Science, Technology, Engineering, and Mathematics
Spears, Jacqueline D.; Dyer, Ruth A.; Franks, Suzanne E.; Montelone, Beth A.
Women today constitute over half of the U.S. population and almost half of its overall workforce, yet they make up less than a quarter of the science and engineering workforce. Many historical and social factors contribute to this discrepancy, and numerous individual, institutional, and governmental attempts have been made to redress it. However, many of the efforts to promote, include, and engage girls and women in science, technology, engineering, and mathematics (STEM) education and professions have been made in isolation. At Kansas State University, the authors have begun a systemic effort to increase the participation of girls and women in STEM. This article describes the creation and initial activities of a network of partners that includes universities, school districts, corporations, governmental agencies, and nonprofit organizations, assembled under the aegis of a project supported by funding from the National Science Foundation.
HISTORY OF THE ENGINEERING PHYSICS AND MATHEMATICS DIVISION 1955-1993
Energy Technology Data Exchange (ETDEWEB)
Maskewitz, B.F.
2001-09-14
A review of division progress reports noting significant events and findings of the Applied Nuclear Physics, Neutron Physics, Engineering Physics, and then Engineering Physics and Mathematics divisions from 1955 to 1993 was prepared for use in developing a history of the Oak Ridge National Laboratory in celebration of its 50th year. The research resulted in an accumulation of historic material and photographs covering 38 years of effort, and the decision was made to publish a brief history of the division. The history begins with a detailed account of the founding of the Applied Nuclear Physics Division in 1955 and continues through the name change to the Neutron Physics Division in the late 1950s. The material thereafter is presented in decades--the sixties, seventies, and eighties--and ends as we enter the nineties.
International Nuclear Information System (INIS)
Ai Baoquan; Wang Liqiu; Liu Lianggang
2006-01-01
We study the thermodynamic features of a thermal motor driven by temperature differences, which consists of a Brownian particle moving in a sawtooth potential with an external load. The motor can work as a heat engine or a refrigerator under different conditions. The heat flow driven by both potential and kinetic energy is considered. The former is reversible when the engine works quasistatically and the latter is always irreversible. The efficiency of the heat engine (Coefficient Of Performance (COP) of a refrigerator) can never approach Carnot efficiency (COP)
International Nuclear Information System (INIS)
Açıkkalp, Emin
2017-01-01
Highlights: • An irreversible MCFC - Braysson heat engine is considered. • Its performance is investigated with ecological approach. • A new ecological criteria are presented called as modified ecological function. • Result are obtained numerically and discussed. - Abstract: An irreversible hybrid molten carbonate fuel cell-Braysson heat engine is taken into account. Basic thermodynamics parameters including power output, efficiency and exergy destruction rate are considered. In addition ecological function and new criteria, which is based on ecological function, for heat engines called as modified ecological function is suggested. Optimum conditions for mentioned parameters above are determined. Numerical results are obtained and plotted. Finally, results are discussed.
Effects of irreversibility and economics on the performance of a heat engine
International Nuclear Information System (INIS)
Ibrahim, O.M.; Klein, S.A.; Mitchell, J.W.
1992-01-01
In this paper, optimization of the power output of an internally irreversible heat engine is considered for finite capacitance rates of the external fluid streams. The method of Lagrange multipliers is used to solve for working fluid temperatures which yield maximum power. Analytical expressions for the maximum power and the cycle efficiency at miximum power are obtained. The effects of irreversibility and economics on the performance of a heat engine are investigated. A relationship between the maximum power point and economically optimum design is identified. It is demonstrated that, with certain reasonable economic assumptions, the maximum power point of a heat engine corresponds to a point of minimum life-cycle costs
Welch, C.; Osborne, B.
The UK national STEM Ambassadors programme provides inspiring role models for school students in science, technology, engineering, mathematics (STEM) subjects. STEMNET, the national body responsible for STEM Ambassa- dors aims to provide more than 27,000 STEM Ambassadors nationwide by the end of 2011. This paper reports on a project at Kingston University to embed STEM Ambassador training and activity in Year 2 of the undergraduate Aerospace Engineering, Astronautics and Space Technology degree. The project, known as KUSPACE (Kingston University Students Providing Amazing Classroom Experiences), was conceived to develop students' communication, planning and presentation skills and build links between different cohort years, while providing a valuable contribution to local primary schools' STEM programmes and simultaneously raising the public engagement profile of the university. This paper describes the pedagogical conception of the KUSPACE, its implementation in the curriculum, the delivery of it in the university and schools and its effect on the undergraduate students, as well as identifying good practice and drawing attention to lessons learned.STEMNET (www.stemnet.org) is the UK's Science, Technol- ogy, Engineering and Mathematics Network. Working with a broad range of UK partners and funded by the UK govern- ment's Department for Business Innovation and Skills, STEMNET plays a significant role in ensuring that five to nineteen year olds and their teachers can experience a wide range of activities and schemes which enhance and enrich the school curriculum [1]. Covering all aspects of Science, Tech- nology, Engineering and Maths (STEM), these activities and schemes are designed both to increase STEM awareness and literacy in the young people and also to encourage more of them to undertake post-16 STEM qualifications and associated careers [2]. STEMNET operates through forty-five local con- tract holders around the UK which help the network deliver its
Thin film heat flux sensor for Space Shuttle Main Engine turbine environment
Will, Herbert
1991-01-01
The Space Shuttle Main Engine (SSME) turbine environment stresses engine components to their design limits and beyond. The extremely high temperatures and rapid temperature cycling can easily cause parts to fail if they are not properly designed. Thin film heat flux sensors can provide heat loading information with almost no disturbance of gas flows or of the blade. These sensors can provide steady state and transient heat flux information. A thin film heat flux sensor is described which makes it easier to measure small temperature differences across very thin insulating layers.
Design and evaluation of fluidized bed heat recovery for diesel engine systems
Hamm, J. R.; Newby, R. A.; Vidt, E. J.; Lippert, T. E.
1985-01-01
The potential of utilizing fluidized bed heat exchangers in place of conventional counter-flow heat exchangers for heat recovery from adiabatic diesel engine exhaust gas streams was studied. Fluidized bed heat recovery systems were evaluated in three different heavy duty transport applications: (1) heavy duty diesel truck; (2) diesel locomotives; and (3) diesel marine pushboat. The three applications are characterized by differences in overall power output and annual utilization. For each application, the exhaust gas source is a turbocharged-adiabatic diesel core. Representative subposed exhaust gas heat utilization power cycles were selected for conceptual design efforts including design layouts and performance estimates for the fluidized bed heat recovery heat exchangers. The selected power cycles were: organic rankine with RC-1 working fluid, turbocompound power turbine with steam injection, and stirling engine. Fuel economy improvement predictions are used in conjunction with capital cost estimates and fuel price data to determine payback times for the various cases.
The second law of thermodynamics and quantum heat engines: Is the law strictly enforced?
Keefe, Peter D.
2010-01-01
A quantum heat engine is a construct having a working medium which is cyclically processed through a pair of control variables of state involving a Bose-Einstein condensation (BEC) in which a heat input is converted into a work output. Of interest is a first species of quantum heat engine in which the working medium is macroscopic in the sense the size scale is sufficiently large that the BEC is not volumetrically coherent. In this first species of quantum heat engine, near Carnot efficiencies may be possible. Of particular interest is a second species of quantum heat engine in which the working medium is mesoscopic in the sense that the size scale is sufficiently small that the BEC is volumetrically coherent. In this second species of quantum heat engine, the resulting in-process non-equilibrium condition affects the finally arrived at control variables of state such that Carnot efficiencies and beyond may be possible. A Type I superconductor is used to model the first and second species of quantum heat engine.
International Nuclear Information System (INIS)
Shadid, John Nicolas; Lehoucq, Richard B.; Christon, Mark Allen; Slepoy, Alexander; Bochev, Pavel Blagoveston; Collis, Samuel Scott; Wagner, Gregory John
2004-01-01
Existing approaches in multiscale science and engineering have evolved from a range of ideas and solutions that are reflective of their original problem domains. As a result, research in multiscale science has followed widely diverse and disjoint paths, which presents a barrier to cross pollination of ideas and application of methods outside their application domains. The status of the research environment calls for an abstract mathematical framework that can provide a common language to formulate and analyze multiscale problems across a range of scientific and engineering disciplines. In such a framework, critical common issues arising in multiscale problems can be identified, explored and characterized in an abstract setting. This type of overarching approach would allow categorization and clarification of existing models and approximations in a landscape of seemingly disjoint, mutually exclusive and ad hoc methods. More importantly, such an approach can provide context for both the development of new techniques and their critical examination. As with any new mathematical framework, it is necessary to demonstrate its viability on problems of practical importance. At Sandia, lab-centric, prototype application problems in fluid mechanics, reacting flows, magnetohydrodynamics (MHD), shock hydrodynamics and materials science span an important subset of DOE Office of Science applications and form an ideal proving ground for new approaches in multiscale science.
International Nuclear Information System (INIS)
Colaluca, M.A.
1990-01-01
Recent experimental evidence suggests the possibility of sulfur cleanup by direct injection at gas temperatures that do not thermodynamically favor the absorption of sulfur by the limestone. The purpose of this paper is to analytically investigate possible mechanistic explanations of this observed sulfur capture with the goal of evaluating the potential for limestone injection sulfur capture in direct coal fired gas turbine and diesel engine (heat engines) combustion applications. The method was to use current available data on the physical properties of limestone, and the rates of the pertinent reactions, and to develop mathematical models of the processes experienced by the sorbent particles. The models were then used to predict extent of capture at the high-pressure, high-temperature, short residence time conditions of interest. The goal was to first investigate capture in a single-pulse reactor (combustion bomb) and then to extrapolate these results to advanced coal-fired heat engine combustion environments. Model predictions were in good agreement with observed sulfur capture in cold wall combustion bomb studies and suggest that efficient sulfur capture (in excess of 80 percent calcium utilization) may b e possible when limestone sorbents are injected into high-temperature combustion products, even when the gas temperatures exceed the thermodynamically favored temperature window by several hundred kelvins. This behavior is possible because particle temperatures are moderated and held at levels that favor sulfur capture due to the strongly endothermic calcination reaction
Osman, Sharifah; Mohammad, Shahrin; Abu, Mohd Salleh
2015-05-01
Mathematics and engineering are inexorably and significantly linked and essentially required in analyzing and accessing thought to make good judgment when dealing in complex and varied engineering problems. A study in the current engineering education curriculum to explore how the critical thinking and mathematical thinking relates to one another, is therefore timely crucial. Unfortunately, there is not much information available explicating about the link. This paper aims to report findings of a critical review as well as to provide brief description of an on-going research aimed to investigate the dispositions of critical thinking and the relationship and integration between critical thinking and mathematical thinking during the execution of civil engineering tasks. The first part of the paper reports an in-depth review on these matters based on rather limited resources. The review showed a considerable form of congruency between these two perspectives of thinking, with some prevalent trends of engineering workplace tasks, problems and challenges. The second part describes an on-going research to be conducted by the researcher to investigate rigorously the relationship and integration between these two types of thinking within the perspective of civil engineering tasks. A reasonably close non-participant observations and semi-structured interviews will be executed for the pilot and main stages of the study. The data will be analyzed using constant comparative analysis in which the grounded theory methodology will be adopted. The findings will serve as a useful grounding for constructing a substantive theory revealing the integral relationship between critical thinking and mathematical thinking in the real civil engineering practice context. The substantive theory, from an angle of view, is expected to contribute some additional useful information to the engineering program outcomes and engineering education instructions, aligns with the expectations of
Basaran, Mehmet; Özalp, Gülümser; Kalender, Ilker; Alacaci, Cengiz
2015-01-01
One important function of school mathematics curriculum is to prepare high school students with the knowledge and skills needed for university education. Identifying them empirically will help making sound decisions about the contents of high school mathematics curriculum. It will also help students to make informed choices in course selection at…
Comparing Two Definitions of Work for a Biological Quantum Heat Engine
International Nuclear Information System (INIS)
Xu You-Yang; Zhao Shun-Cai; Liu Juan
2015-01-01
Systems of photosynthetic reaction centres have been modelled as heat engines, while it has also been reported that the efficiency and power of such heat engines can be enhanced by quantum interference — a trait that has attracted much interest. We compare two definitions of the work of such a photosynthetic heat engine, i.e. definition A used by Weimer et al. and B by Dorfman et al. We also introduce a coherent interaction between donor and acceptor (CIDA) to demonstrate a reversible energy transport. We show that these two definitions of work can impart contradictory results, that is, CIDA enhances the power and efficiency of the photosynthetic heat engine with definition B but not with A. Additionally, we find that both reversible and irreversible excitation-energy transport can be described with definition A, but definition B can only model irreversible transport. As a result, we conclude that definition A is more suitable for photosynthetic systems than definition B. (paper)
International Nuclear Information System (INIS)
Fu, Jianqin; Liu, Jingping; Xu, Zhengxin; Ren, Chengqin; Deng, Banglin
2013-01-01
In this paper, a novel approach for exhaust heat recovery was proposed to improve IC (internal combustion) engine fuel efficiency and also to achieve the goal for direct usage of methanol as IC engine fuel. An open organic Rankine cycle system using methanol as working medium is coupled to IC engine exhaust pipe for exhaust heat recovery. In the bottom cycle, the working medium first undergoes dissociation and expansion processes, and is then directed back to IC engine as fuel. As the external bottom cycle and the IC engine main cycle are combined together, this scheme forms a combined thermodynamic cycle. Then, this concept was applied to a turbocharged engine, and the corresponding simulation models were built for both of the external bottom cycle and the IC engine main cycle. On this basis, the energy saving potential of this combined cycle was estimated by parametric analyses. Compared to the methanol vapor engine, IC engine in-cylinder efficiency has an increase of 1.4–2.1 percentage points under full load conditions, while the external bottom cycle can increase the fuel efficiency by 3.9–5.2 percentage points at the working pressure of 30 bar. The maximum improvement to the IC engine global fuel efficiency reaches 6.8 percentage points. - Highlights: • A combined thermodynamic cycle using methanol as working medium for IC engine exhaust heat recovery is proposed. • The external bottom cycle of exhaust heat recovery and IC engine working cycle are combined together. • IC engine fuel efficiency could be improved from both in-cylinder working cycle and external bottom cycle. • The maximum improvement to the IC engine global fuel efficiency reaches 6.8 percentage points at full load
International Nuclear Information System (INIS)
Shehata, M.S.
2010-01-01
An experimental work were conducted for investigating cylinder pressure, performance parameters, heat release, specific heat ratio and duration of combustion for multi cylinder spark ignition engine (SIE). Ccylinder pressure was measured for gasoline, kerosene and Liquefied Petroleum Gases (LPG) separately as a fuel for SIE. Fast Fourier Transformations (FFT) was used to cylinder pressure data transform from time domain into frequency domain to develop empirical correlation for calculating cylinder pressures at different engine speeds and different fuels. In addition, Inverse Fast Fourier Transformations (IFFT) was used to cylinder pressure reconstruct into time domain. The results gave good agreement between the measured cylinder pressure and the reconstructed cylinder pressure in time domain with different engine speeds and different fuels. The measured cylinder pressure and hydraulic dynamotor were the sours of data for calculating engine performance parameters. First law of thermodynamics and single zone heat release model with temperature dependant specific heat ratio γ(T) were the main tools for calculating heat release and heat transfer to cylinder walls. Third order empirical correlation for calculating γ(T) was one of the main gains of the present study. The correlation gave good agreement with other researchers with wide temperatures range. For kerosene, cylinder pressure is higher than for gasoline and LPG due to high volumetric efficiency where kerosene density (mass/volume ratio) is higher than gasoline and LPG. In addition, kerosene heating value is higher than gasoline that contributes in heat release rate and pressure increases. Duration of combustion for different engine speeds was determined using four different methods: (I) Mass fuel burnt, (II) Entropy change, (III) Temperature dependant specific heat ratio γ(T), and (IV) Logarithmic scale of (P and V). The duration of combustion for kerosene is smaller than for gasoline and LPG due to high
Energy Technology Data Exchange (ETDEWEB)
Shehata, M.S. [Mechanical Engineering Technology Department, Higher Institute of Technology, Banha University, 4Zagalol Street, Benha, Galubia 1235 Z (Egypt)
2010-12-15
An experimental work were conducted for investigating cylinder pressure, performance parameters, heat release, specific heat ratio and duration of combustion for multi cylinder spark ignition engine (SIE). Ccylinder pressure was measured for gasoline, kerosene and Liquefied Petroleum Gases (LPG) separately as a fuel for SIE. Fast Fourier Transformations (FFT) was used to cylinder pressure data transform from time domain into frequency domain to develop empirical correlation for calculating cylinder pressures at different engine speeds and different fuels. In addition, Inverse Fast Fourier Transformations (IFFT) was used to cylinder pressure reconstruct into time domain. The results gave good agreement between the measured cylinder pressure and the reconstructed cylinder pressure in time domain with different engine speeds and different fuels. The measured cylinder pressure and hydraulic dynamotor were the source of data for calculating engine performance parameters. First law of thermodynamics and single zone heat release model with temperature dependant specific heat ratio {gamma}(T) were the main tools for calculating heat release and heat transfer to cylinder walls. Third order empirical correlation for calculating {gamma}(T) was one of the main gains of the present study. The correlation gave good agreement with other researchers with wide temperatures range. For kerosene, cylinder pressure is higher than for gasoline and LPG due to high volumetric efficiency where kerosene density (mass/volume ratio) is higher than gasoline and LPG. In addition, kerosene heating value is higher than gasoline that contributes in heat release rate and pressure increases. Duration of combustion for different engine speeds was determined using four different methods: (I) Mass fuel burnt, (II) Entropy change, (III) Temperature dependant specific heat ratio {gamma}(T), and (IV) Logarithmic scale of (P and V). The duration of combustion for kerosene is smaller than for gasoline and
On the thermodynamics of waste heat recovery from internal combustion engine exhaust gas
Meisner, G. P.
2013-03-01
The ideal internal combustion (IC) engine (Otto Cycle) efficiency ηIC = 1-(1/r)(γ - 1) is only a function of engine compression ratio r =Vmax/Vmin and exhaust gas specific heat ratio γ = cP/cV. Typically r = 8, γ = 1.4, and ηIC = 56%. Unlike the Carnot Cycle where ηCarnot = 1-(TC/TH) for a heat engine operating between hot and cold heat reservoirs at TH and TC, respectively, ηIC is not a function of the exhaust gas temperature. Instead, the exhaust gas temperature depends only on the intake gas temperature (ambient), r, γ, cV, and the combustion energy. The ejected exhaust gas heat is thermally decoupled from the IC engine and conveyed via the exhaust system (manifold, pipe, muffler, etc.) to ambient, and the exhaust system is simply a heat engine that does no useful work. The maximum fraction of fuel energy that can be extracted from the exhaust gas stream as useful work is (1-ηIC) × ηCarnot = 32% for TH = 850 K (exhaust) and TC = 370 K (coolant). This waste heat can be recovered using a heat engine such as a thermoelectric generator (TEG) with ηTEG> 0 in the exhaust system. A combined IC engine and TEG system can generate net useful work from the exhaust gas waste heat with efficiency ηWH = (1-ηIC) × ηCarnot ×ηTEG , and this will increase the overall fuel efficiency of the total system. Recent improvements in TEGs yield ηTEG values approaching 15% giving a potential total waste heat conversion efficiency of ηWH = 4.6%, which translates into a fuel economy improvement approaching 5%. This work is supported by the US DOE under DE-EE0005432.
Heat Transfer in Two-Stroke Diesel Engines for Large Ship Propulsion
DEFF Research Database (Denmark)
Christiansen, Caspar Ask
Demands on reducing the fuel consumption and harmful emissions from the compression ignition engines (diesel engines) have been continuously increasing in recent years. To comply with this, better modeling tools for the diesel combustion process are desired from the engine developers. A very......%, 30% and 50% load) was performed on a MAN Diesel & Turbo SE test engine, which shows very promising results for further investigations of dynamic temperature and heat flux in large bore engines. Instantaneous heat flux is derived using both an analytical and a numerical model and compared. More...... was investigated by computer simulations using a 3-D numerical finite volume model made in STAR-CD. General trends are observed from the temperature measurements in the limited part load range. These include among others: local increase in mean surface temperature and mean surface heat flux with increasing load...
Improving the engineering strength of heat strengthened glass
Veer, F.A.; Rodichev, YM
2016-01-01
Although glass is increasingly used as a structural material, glass is not produced to strength standards, like steel and concrete. Of the three types of glass: annealed, heat strengthened and fully tempered, only heat strengthened glass has the properties to function as a safe structural material.
Engineering economic assessment of residential wood heating in NY
We provide insight into the recent resurgence in residential wood heating in New York by: (i) examining the lifetime costs of outdoor wood hydronic heaters (OWHHs) and other whole-house residential wood heat devices,(ii) comparing these lifetime costs with those of competing tech...
Integration of a wood pellet burner and a Stirling engine to produce residential heat and power
International Nuclear Information System (INIS)
Cardozo, Evelyn; Erlich, Catharina; Malmquist, Anders; Alejo, Lucio
2014-01-01
The integration a Stirling engine with a pellet burner is a promising alternative to produce heat and power for residential use. In this context, this study is focused on the experimental evaluation of the integration of a 20 kW th wood pellet burner and a 1 kW e Stirling engine. The thermal power not absorbed by the engine is used to produce hot water. The evaluation highlights the effects of pellet type, combustion chamber length and cycling operation on the Stirling engine temperatures and thermal power absorbed. The results show that the position of the Stirling engine is highly relevant in order to utilize as much as possible of the radiative heat from the burner. Within this study, only a 5 cm distance change between the Stirling engine and the pellet burner could result in an increase of almost 100 °C in the hot side of the engine. However, at a larger distance, the temperature of the hot side is almost unchanged suggesting dominating convective heat transfer from the hot flue gas. Ash accumulation decreases the temperature of the hot side of the engine after some cycles of operation when a commercial pellet burner is integrated. The temperature ratio, which is the relation between the minimum and maximum temperatures of the engine, decreases when using Ø8 mm wood pellets in comparison to Ø6 mm pellets due to higher measured temperatures on the hot side of the engine. Therefore, the amount of heat supplied to the engine is increased for Ø8 mm wood pellets. The effectiveness of the engine regenerator is increased at higher pressures. The relation between temperature of the hot side end and thermal power absorbed by the Stirling engine is nearly linear between 500 °C and 660 °C. Higher pressure inside the Stirling engine has a positive effect on the thermal power output. Both the chemical and thermal losses increase somewhat when integrating a Stirling engine in comparison to a stand-alone boiler for only heat production. The overall efficiency
Starobin, Soko S.; Laanan, Frankie Santos
Female and minority students have historically been underrepresented in the field of science, mathematics, and engineering at colleges and universities. Although a plethora of research has focused on students enrolled in 4-year colleges or universities, limited research addresses the factors that influence gender differences in community college students in science, mathematics, and engineering. Using a target population of 1,599 aspirants in science, mathematics, and engineering majors in public community colleges, this study investigates the determinants of self-concept by examining a hypothetical structural model. The findings suggest that background characteristics, high school academic performance, and attitude toward science have unique contributions to the development of self-concept among female community college students. The results add to the literature by providing new theoretical constructs and the variables that predict students' self-concept.
Exergy, Economic and Environmental Analysis for Simple and Combined Heat and Power IC Engines
Directory of Open Access Journals (Sweden)
Mehdi Aliehyaei
2015-04-01
Full Text Available This study reports the results of exergy, economic and environmental analyses of simple and combined heat and power internal combustion engines. Values of entropy production, second law efficiency are calculated, and an objective function, including initial, operation, maintenance and fuel costs, as well as the external costs of environmental pollutants, such as CO2, CO and NOx, are presented for the flue gas of the internal combustion engine. The results show that entropy generation in the combined heat and power mode is 30% lower than that in the simple internal combustion engine. Also, by excessively increasing the air ratio, the system entropy generation decreases in both cases of simple and combined heat and power IC engines. The greatest portion of entropy generation is related to the combined heat and power internal combustion engine. The gas heat exchanger generates more entropy than the jacket heat exchanger. Lower values of electricity cost and external costs of air pollution are provided by higher values of molar air to fuel ratio. The environmental aspects depend on location of the system and time of engine operation.
Gradient heat flux measurement as monitoring method for the diesel engine
Sapozhnikov, S. Z.; Mityakov, V. Yu; Mityakov, A. V.; Vintsarevich, A. V.; Pavlov, A. V.; Nalyotov, I. D.
2017-11-01
The usage of gradient heat flux measurement for monitoring of heat flux on combustion chamber surface and optimization of diesel work process is proposed. Heterogeneous gradient heat flux sensors can be used at various regimes for an appreciable length of time. Fuel injection timing is set by the position of the maximum point on the angular heat flux diagram however, the value itself of the heat flux may not be considered. The development of such an approach can be productive for remote monitoring of work process in the cylinders of high-power marine engines.
International Nuclear Information System (INIS)
Chen, Liwei; Zhang, Houcheng; Gao, Songhua; Yan, Huixian
2014-01-01
A new hybrid system mainly consists of a molten carbonate fuel cell (MCFC) and a Stirling heat engine is established, where the Stirling heat engine is driven by the high-quality waste heat generated in the MCFC. Based on the electrochemistry and non-equilibrium thermodynamics, analytical expressions for the efficiency and power output of the hybrid system are derived by taking various irreversible losses into account. It shows that the performance of the MCFC can be greatly enhanced by coupling a Stirling heat engine to further convert the waste heat for power generation. By employing numerical calculations, not only the influences of multiple irreversible losses on the performance of the hybrid system are analyzed, but also the impacts of some operating conditions such as the operating temperature, input gas compositions and operating pressure on the performance of the hybrid system are also discussed. The investigation method in the present paper is feasible for some other similar energy conversion systems as well. - Highlights: • A model of MCFC–Stirling heat engine hybrid system is established. • Analytical expressions for the efficiency and power output are derived. • MCFC performance can be greatly enhanced by coupling a Stirling heat engine. • Effects of some operating conditions on the performance are discussed. • Optimum operation regions are subdivided by multi-objective optimization method
Heat exchanger design for hot air ericsson-brayton piston engine
Directory of Open Access Journals (Sweden)
Ďurčanský P.
2014-03-01
Full Text Available One of the solutions without negative consequences for the increasing energy consumption in the world may be use of alternative energy sources in micro-cogeneration. Currently it is looking for different solutions and there are many possible ways. Cogeneration is known for long time and is widely used. But the installations are often large and the installed output is more suitable for cities or industry companies. When we will speak about decentralization, the small machines have to be used. The article deals with the principle of hot-air engines, their use in combined heat and electricity production from biomass and with heat exchangers as primary energy transforming element. In the article is hot air engine presented as a heat engine that allows the conversion of heat into mechanical energy while heat supply can be external. In the contribution are compared cycles of hot-air engine. Then are compared suitable heat exchangers for use with hot air Ericsson-Brayton engine. In the final part is proposal of heat exchanger for use in closed Ericsson-Brayton cycle.
Heat exchanger design for hot air ericsson-brayton piston engine
Ďurčanský, P.; Lenhard, R.; Jandačka, J.
2014-03-01
One of the solutions without negative consequences for the increasing energy consumption in the world may be use of alternative energy sources in micro-cogeneration. Currently it is looking for different solutions and there are many possible ways. Cogeneration is known for long time and is widely used. But the installations are often large and the installed output is more suitable for cities or industry companies. When we will speak about decentralization, the small machines have to be used. The article deals with the principle of hot-air engines, their use in combined heat and electricity production from biomass and with heat exchangers as primary energy transforming element. In the article is hot air engine presented as a heat engine that allows the conversion of heat into mechanical energy while heat supply can be external. In the contribution are compared cycles of hot-air engine. Then are compared suitable heat exchangers for use with hot air Ericsson-Brayton engine. In the final part is proposal of heat exchanger for use in closed Ericsson-Brayton cycle.
Directory of Open Access Journals (Sweden)
Haritonova Larisa
2017-01-01
Full Text Available The article gives the analytical generalization of the data on the energy efficiency for heat exchangers with the flat heat exchange surface to which systems of impact plane parallel jets are sent. Functional relations of specific power consumption (per unit of area, which were obtained for the first time using the techniques of the similarity law, for moving a heat carrier are shown with regard to design and operation factors. The regression equations representing a mathematical model of the process enable to carry out an analysis of various factors impact on the parameter to be determined. The obtained results can be used to optimize or to create the calculation techniques for new highly-efficient heat exchange devices with jet plane -parallel impingement systems and also to reduce power consumption for moving a heat carrier.
Towards intelligent diagnostic system employing integration of mathematical and engineering model
International Nuclear Information System (INIS)
Isa, Nor Ashidi Mat
2015-01-01
The development of medical diagnostic system has been one of the main research fields during years. The goal of the medical diagnostic system is to place a nosological system that could ease the diagnostic evaluation normally performed by scientists and doctors. Efficient diagnostic evaluation is essentials and requires broad knowledge in order to improve conventional diagnostic system. Several approaches on developing the medical diagnostic system have been designed and tested since the earliest 60s. Attempts on improving their performance have been made which utilizes the fields of artificial intelligence, statistical analyses, mathematical model and engineering theories. With the availability of the microcomputer and software development as well as the promising aforementioned fields, medical diagnostic prototypes could be developed. In general, the medical diagnostic system consists of several stages, namely the 1) data acquisition, 2) feature extraction, 3) feature selection, and 4) classifications stages. Data acquisition stage plays an important role in converting the inputs measured from the real world physical conditions to the digital numeric values that can be manipulated by the computer system. One of the common medical inputs could be medical microscopic images, radiographic images, magnetic resonance image (MRI) as well as medical signals such as electrocardiogram (ECG) and electroencephalogram (EEG). Normally, the scientist or doctors have to deal with myriad of data and redundant to be processed. In order to reduce the complexity of the diagnosis process, only the significant features of the raw data such as peak value of the ECG signal or size of lesion in the mammogram images will be extracted and considered in the subsequent stages. Mathematical models and statistical analyses will be performed to select the most significant features to be classified. The statistical analyses such as principal component analysis and discriminant analysis as well
Towards intelligent diagnostic system employing integration of mathematical and engineering model
Isa, Nor Ashidi Mat
2015-05-01
The development of medical diagnostic system has been one of the main research fields during years. The goal of the medical diagnostic system is to place a nosological system that could ease the diagnostic evaluation normally performed by scientists and doctors. Efficient diagnostic evaluation is essentials and requires broad knowledge in order to improve conventional diagnostic system. Several approaches on developing the medical diagnostic system have been designed and tested since the earliest 60s. Attempts on improving their performance have been made which utilizes the fields of artificial intelligence, statistical analyses, mathematical model and engineering theories. With the availability of the microcomputer and software development as well as the promising aforementioned fields, medical diagnostic prototypes could be developed. In general, the medical diagnostic system consists of several stages, namely the 1) data acquisition, 2) feature extraction, 3) feature selection, and 4) classifications stages. Data acquisition stage plays an important role in converting the inputs measured from the real world physical conditions to the digital numeric values that can be manipulated by the computer system. One of the common medical inputs could be medical microscopic images, radiographic images, magnetic resonance image (MRI) as well as medical signals such as electrocardiogram (ECG) and electroencephalogram (EEG). Normally, the scientist or doctors have to deal with myriad of data and redundant to be processed. In order to reduce the complexity of the diagnosis process, only the significant features of the raw data such as peak value of the ECG signal or size of lesion in the mammogram images will be extracted and considered in the subsequent stages. Mathematical models and statistical analyses will be performed to select the most significant features to be classified. The statistical analyses such as principal component analysis and discriminant analysis as well
Towards intelligent diagnostic system employing integration of mathematical and engineering model
Energy Technology Data Exchange (ETDEWEB)
Isa, Nor Ashidi Mat [Imaging and Intelligent System Research Team (ISRT), School of Electrical and Electronic Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)
2015-05-15
The development of medical diagnostic system has been one of the main research fields during years. The goal of the medical diagnostic system is to place a nosological system that could ease the diagnostic evaluation normally performed by scientists and doctors. Efficient diagnostic evaluation is essentials and requires broad knowledge in order to improve conventional diagnostic system. Several approaches on developing the medical diagnostic system have been designed and tested since the earliest 60s. Attempts on improving their performance have been made which utilizes the fields of artificial intelligence, statistical analyses, mathematical model and engineering theories. With the availability of the microcomputer and software development as well as the promising aforementioned fields, medical diagnostic prototypes could be developed. In general, the medical diagnostic system consists of several stages, namely the 1) data acquisition, 2) feature extraction, 3) feature selection, and 4) classifications stages. Data acquisition stage plays an important role in converting the inputs measured from the real world physical conditions to the digital numeric values that can be manipulated by the computer system. One of the common medical inputs could be medical microscopic images, radiographic images, magnetic resonance image (MRI) as well as medical signals such as electrocardiogram (ECG) and electroencephalogram (EEG). Normally, the scientist or doctors have to deal with myriad of data and redundant to be processed. In order to reduce the complexity of the diagnosis process, only the significant features of the raw data such as peak value of the ECG signal or size of lesion in the mammogram images will be extracted and considered in the subsequent stages. Mathematical models and statistical analyses will be performed to select the most significant features to be classified. The statistical analyses such as principal component analysis and discriminant analysis as well
Finite-Time Thermoeconomic Optimization of a Solar-Driven Heat Engine Model
Directory of Open Access Journals (Sweden)
Fernando Angulo-Brown
2011-01-01
Full Text Available In the present paper, the thermoeconomic optimization of an irreversible solar-driven heat engine model has been carried out by using finite-time/finite-size thermodynamic theory. In our study we take into account losses due to heat transfer across finite time temperature differences, heat leakage between thermal reservoirs and internal irreversibilities in terms of a parameter which comes from the Clausius inequality. In the considered heat engine model, the heat transfer from the hot reservoir to the working fluid is assumed to be Dulong-Petit type and the heat transfer to the cold reservoir is assumed of the Newtonian type. In this work, the optimum performance and two design parameters have been investigated under two objective functions: the power output per unit total cost and the ecological function per unit total cost. The effects of the technical and economical parameters on the thermoeconomic performance have been also discussed under the aforementioned two criteria of performance.
Evaporation and condensation devices for passive heat removal systems in nuclear power engineering
International Nuclear Information System (INIS)
Gershuni, A.N.; Pis'mennyj, E.N.; Nishchik, A.P.
2016-01-01
The paper justifies advantages of evaporation and condensation heat transfer devices as means of passive heat removal and thermal shielding in nuclear power engineering. The main thermophysical factors that limit heat transfer capacity of evaporation and condensation systems have been examined in the research. The results of experimental studies of heat engineering properties of elongated (8-m) vertically oriented evaporation and condensation devices (two-phase thermosyphons), which showed a high enough heat transfer capacity, as well as stability and reliability both in steady state and in start-up modes, are provided. The paper presents the examples of schematic designs of evaporation and condensation systems for passive heat removal and thermal shielding in application to nuclear power equipment
Waste heat recovery system for recapturing energy after engine aftertreatment systems
Ernst, Timothy C.; Nelson, Christopher R.
2014-06-17
The disclosure provides a waste heat recovery (WHR) system including a Rankine cycle (RC) subsystem for converting heat of exhaust gas from an internal combustion engine, and an internal combustion engine including the same. The WHR system includes an exhaust gas heat exchanger that is fluidly coupled downstream of an exhaust aftertreatment system and is adapted to transfer heat from the exhaust gas to a working fluid of the RC subsystem. An energy conversion device is fluidly coupled to the exhaust gas heat exchanger and is adapted to receive the vaporized working fluid and convert the energy of the transferred heat. The WHR system includes a control module adapted to control at least one parameter of the RC subsystem based on a detected aftertreatment event of a predetermined thermal management strategy of the aftertreatment system.
Building an Understanding of Heat Transfer Concepts in Undergraduate Chemical Engineering Courses
Nottis, Katharyn E. K.; Prince, Michael J.; Vigeant, Margot A.
2010-01-01
Understanding the distinctions among heat, energy and temperature can be difficult for students at all levels of instruction, including those in engineering. Misconceptions about heat transfer have been found to persist, even after students successfully complete relevant coursework. New instructional methods are needed to address these…
The Amount of Regenerated Heat Inside the Regenerator of a Stirling Engine
Directory of Open Access Journals (Sweden)
J. Škorpík
2008-01-01
Full Text Available The paper deals with analytical computing of the regenerated heat inside the regenerator of a Stirling engine. The total sum of the regenerated heat is constructed as a function of the crank angle in the case of Schmidt’s idealization.
Energy Technology Data Exchange (ETDEWEB)
Schoen, E. (Ruhrgas A.G., Essen (Germany, F.R.). Abt. E-F)
1978-01-01
The contribution illustrates, from the industrial viewpoint, how one may produce process heat rationally and make optimum use of it using natural gas and how competing fuels can be supplanted. The heat economy engineering activities of a modern gas supply undertaking and a few practical examples to improve the industrial produce structure are shown.
Fuel effects on knock, heat releases and CARS temperatures in a spark ignition engine
Kalghatgi, G.T.; Golombok, M.; Snowdon, P.
1995-01-01
Net heat release, knock characteristics and temperature were derived from in-cylinder pressure and end-gas CARS measurements for different fuels in a single-cylinder engine. The maximum net heat release rate resulting from the final phase of autoignition is closely associated with knock intensity.
Directory of Open Access Journals (Sweden)
Irina Carmen ANDREI
2015-09-01
Full Text Available The purpose of this paper is to set up a method to determine the missing engine design parameters (turbine inlet temperature T3T, airflow rate which significantly influence the jet engines thrust. The authors have introduced a new non-linear equation connecting the fan specific work with the temperature T3T, customized for turbofan. The method of chords, since it converges unconditionally, has been used for solving the non-linear equation of variable temperature T3T. An alternate method, based for the same relation between fan specific work and T3T, has been presented in purpose to determine airflow rate and fan pressure ratio. Two mixed flows turbofans have been considered as study cases. For case #1 it was determined a value comparable to the Turbomeca Larzac turbofan series 04-C6 and 04-C20 which power the AlphaJet machines (series A - Luftwaffe, series E - Dassault Dornier. For the F100-PW229 turbofan, as case #2, being given T3T, then have been determined the airflow rate, fan pressure ratio and fan specific work. After completing the mathematical model with the missing parameters, the performances of the engines at off-design regimes and the operational envelopes revealing i.e. the variations of thrust, specific thrust and fuel specific consumption with altitude and Mach number have been calculated.
Heat Transfer and Fluid Dynamics Measurements in the Expansion Space of a Stirling Cycle Engine
Jiang, Nan; Simon, Terrence W.
2006-01-01
The heater (or acceptor) of a Stirling engine, where most of the thermal energy is accepted into the engine by heat transfer, is the hottest part of the engine. Almost as hot is the adjacent expansion space of the engine. In the expansion space, the flow is oscillatory, impinging on a two-dimensional concavely-curved surface. Knowing the heat transfer on the inside surface of the engine head is critical to the engine design for efficiency and reliability. However, the flow in this region is not well understood and support is required to develop the CFD codes needed to design modern Stirling engines of high efficiency and power output. The present project is to experimentally investigate the flow and heat transfer in the heater head region. Flow fields and heat transfer coefficients are measured to characterize the oscillatory flow as well as to supply experimental validation for the CFD Stirling engine design codes. Presented also is a discussion of how these results might be used for heater head and acceptor region design calculations.
Quantum lubrication: Suppression of friction in a first-principles four-stroke heat engine
Feldmann, Tova; Kosloff, Ronnie
2006-02-01
A quantum model of a heat engine resembling the Otto cycle is employed to explore strategies to suppress frictional losses. These losses are caused by the inability of the engine’s working medium to follow adiabatically the change in the Hamiltonian during the expansion and compression stages. By adding external noise to the engine frictional losses can be suppressed.
To capabilities of heat engines with gas working medium in closed cycle
International Nuclear Information System (INIS)
Kotov, V.M.; Tikhomirov, L.N.; Rajkhanov, N.A.; Kotov, S.V.
2003-01-01
The effort gives analysis of performance of engines and heat pumps with closed cycles based on use of well practiced adiabatic and isobaric processes. Advantages of theses cycles are demonstrated as compared to Stirling engines, and capabilities of their application in piston machines. (author)
Mathematical programming model for heat exchanger design through optimization of partial objectives
International Nuclear Information System (INIS)
Onishi, Viviani C.; Ravagnani, Mauro A.S.S.; Caballero, José A.
2013-01-01
Highlights: • Rigorous design of shell-and-tube heat exchangers according to TEMA standards. • Division of the problem into sets of equations that are easier to solve. • Selected heuristic objective functions based on the physical behavior of the problem. • Sequential optimization approach to avoid solutions stuck in local minimum. • The results obtained with this model improved the values reported in the literature. - Abstract: Mathematical programming can be used for the optimal design of shell-and-tube heat exchangers (STHEs). This paper proposes a mixed integer non-linear programming (MINLP) model for the design of STHEs, following rigorously the standards of the Tubular Exchanger Manufacturers Association (TEMA). Bell–Delaware Method is used for the shell-side calculations. This approach produces a large and non-convex model that cannot be solved to global optimality with the current state of the art solvers. Notwithstanding, it is proposed to perform a sequential optimization approach of partial objective targets through the division of the problem into sets of related equations that are easier to solve. For each one of these problems a heuristic objective function is selected based on the physical behavior of the problem. The global optimal solution of the original problem cannot be ensured even in the case in which each of the sub-problems is solved to global optimality, but at least a very good solution is always guaranteed. Three cases extracted from the literature were studied. The results showed that in all cases the values obtained using the proposed MINLP model containing multiple objective functions improved the values presented in the literature
International Nuclear Information System (INIS)
Hosoz, M.; Direk, M.; Yigit, K.S.; Canakci, M.; Alptekin, E.; Turkcan, A.
2009-01-01
Because the amount of waste heat used for comfort heating of the passenger compartment in motor vehicles decreases continuously as a result of the increasing engine efficiencies originating from recent developments in internal combustion engine technology, it is estimated that heat requirement of the passenger compartment in vehicles using future generation diesel engines will not be met by the waste heat taken from the engine coolant. The automotive heat pump (AHP) system can heat the passenger compartment individually, or it can support the present heating system of the vehicle. The AHP system can also be employed in electric vehicles, which do not have waste heat, as well as vehicles driven by a fuel cell. The authors of this paper observed that such an AHP system using ambient air as a heat source could not meet the heat requirement of the compartment when ambient temperature was extremely low. The reason is the decrease in the amount of heat taken from the ambient air as a result of low evaporating temperatures. Furthermore, the moisture condensed from air freezed on the evaporator surface, thus blocking the air flow through it. This problem can be solved by using the heat of engine coolant or exhaust gases. In this case, the AHP system can have a higher heating capacity and reuse waste heat. (author)
Experimental study on heat storage system using phase-change material in a diesel engine
International Nuclear Information System (INIS)
Park, Sangki; Woo, Seungchul; Shon, Jungwook; Lee, Kihyung
2017-01-01
Engines usually use only about 25% of the total fuel energy for power, and the rest is discarded to the cooling water and exhaust gas. Therefore, a technique for utilizing external waste heat is required to improve fuel efficiency in terms of total energy consumption. In this study, a heat storage system was built using a phase-change material in order to recover about 30% of the thermal energy wasted through engine cooling. The components of the heat storage system were divided into phase-change material, a heat exchanger, and a heat-insulating container. For each component, a phase-change material that is suitable for use in vehicles was selected based on the safety, thermal properties, and durability. As a result, a stearic acid of a fatty acid series with natural extracts was determined to be appropriate. In order to measure the reduction in engine fuel consumption, a thermal storage system designed for the actual engine was applied to realize a quick warm-up by releasing stored heat energy directly on the coolant during a cold start. This technique added about 95 calories of heat storage device warm-up time compared to the non-added state, which was reduced by about 18.1% to about 27.1%. - Highlights: • The diesel engine used phase-change material with heat storage system. • The thermal storage system designed for the actual engine. • A stearic acid of a fatty acid series was determined to be appropriate. • Applied heat storage system was reduced by about 18.1%–27.1%.
Applicability of advanced automotive heat engines to solar thermal power
Beremand, D. G.; Evans, D. G.; Alger, D. L.
The requirements of a solar thermal power system are reviewed and compared with the predicted characteristics of automobile engines under development. A good match is found in terms of power level and efficiency when the automobile engines, designed for maximum powers of 65-100 kW (87 to 133 hp) are operated to the nominal 20-40 kW electric output requirement of the solar thermal application. At these reduced power levels it appears that the automotive gas turbine and Stirling engines have the potential to deliver the 40+ percent efficiency goal of the solar thermal program.
Energy Efficient Waste Heat Recovery from an Engine Exhaust System
2016-12-01
costs for the operation of the ship. The types of boilers used in this process are specially built to have water flowing around thousands of tubes ...uneven heating of the water and metal heat exchanger, leading to damage or possible failure of the boiler . Since the merchant vessels operate at near...one of the central boiler tubes . Each of the sensors was individually adjusted to ensure that the readings were as accurate as possible to allow for
International Nuclear Information System (INIS)
Engelhardt, G.; Urquidi-Macdonald, M.; Sikora, J.; Macdonald, D.D.
1995-01-01
A predictive and self-consistent mathematical model has been developed to describe the localized corrosion in steam generators. The model recognizes that the internal and external environment are coupled by the need to conserve charge in the system. Thus, solution of Laplace's equation for the external environment (outside the crevice) provides the boundary condition for the electric potential at the crevice mouth, which is needed for solving the system of mass transfer equations for the internal environment (inside the crevice). Mass transfer by diffusion, ion migration, and convection was considered. Heat and momentum transfer equations are solved simultaneously, with the mass balance equation for each species and the condition of electroneutrality inside the cavity being considered. The model takes into account the porosity and tortuosity in the corrosion product deposit in the crevice. The homogeneous chemical reactions (hydrolysis of the products of the anodic reaction and the autoprotolysis of water) are included in the model. The model, in this preliminary form predicts the solution chemistry, potential drop, and temperature distribution inside the crevice. An order of magnitude estimate of the crevice corrosion rate also obtained. At this point, the model predicts only the steady state solution, but it is recognized that a steady state may not exist under normal conditions
Electrical performances of pyroelectric bimetallic strip heat engines describing a Stirling cycle
Arnaud, A.; Boughaleb, J.; Monfray, S.; Boeuf, F.; Cugat, O.; Skotnicki, T.
2015-12-01
This paper deals with the analytical modeling of pyroelectric bimetallic strip heat engines. These devices are designed to exploit the snap-through of a thermo-mechanically bistable membrane to transform a part of the heat flowing through the membrane into mechanical energy and to convert it into electric energy by means of a piezoelectric layer deposited on the surface of the bistable membrane. In this paper, we describe the properties of these heat engines in the case when they complete a Stirling cycle, and we evaluate the performances (available energy, Carnot efficiency...) of these harvesters at the macro- and micro-scale.
Universal Trade-Off between Power, Efficiency, and Constancy in Steady-State Heat Engines
Pietzonka, Patrick; Seifert, Udo
2018-05-01
Heat engines should ideally have large power output, operate close to Carnot efficiency and show constancy, i.e., exhibit only small fluctuations in this output. For steady-state heat engines, driven by a constant temperature difference between the two heat baths, we prove that out of these three requirements only two are compatible. Constancy enters quantitatively the conventional trade-off between power and efficiency. Thus, we rationalize and unify recent suggestions for overcoming this simple trade-off. Our universal bound is illustrated for a paradigmatic model of a quantum dot solar cell and for a Brownian gyrator delivering mechanical work against an external force.
A quantum Otto engine with finite heat baths
DEFF Research Database (Denmark)
Pozas-Kerstjens, Alejandro; Brown, Eric G.; Hovhannisyan, Karen V.
2018-01-01
We study a driven harmonic oscillator operating an Otto cycle by strongly interacting with two thermal baths of finite size. Using the tools of Gaussian quantum mechanics, we directly simulate the dynamics of the engine as a whole, without the need to make any approximations. This allows us...... to understand the non-equilibrium thermodynamics of the engine not only from the perspective of the working medium, but also as it is seen from the thermal baths' standpoint. For sufficiently large baths, our engine is capable of running a number of perfect cycles, delivering finite power while operating very...... close to maximal efficiency. Thereafter, having traversed the baths, the perturbations created by the interaction abruptly deteriorate the engine's performance. Weadditionally study the correlations generated in the system, and, in particular, we find a direct connection between the build up of bath...
Optimal design of Stirling heat engine using an advanced ...
Indian Academy of Sciences (India)
R V Rao
The comparisons of the proposed algorithm are made with those obtained by using the decision-making methods like linear ... cooling water and had improved the thermal efficiency of ... integrated system of a free-piston Stirling engine and an.
LeBeau, Brandon; Harwell, Michael; Monson, Debra; Dupuis, Danielle; Medhanie, Amanuel; Post, Thomas R.
2012-04-01
Background: The importance of increasing the number of US college students completing degrees in science, technology, engineering or mathematics (STEM) has prompted calls for research to provide a better understanding of factors related to student participation in these majors, including the impact of a student's high-school mathematics curriculum. Purpose: This study examines the relationship between various student and high-school characteristics and completion of a STEM major in college. Of specific interest is the influence of a student's high-school mathematics curriculum on the completion of a STEM major in college. Sample: The sample consisted of approximately 3500 students from 229 high schools. Students were predominantly Caucasian (80%), with slightly more males than females (52% vs 48%). Design and method: A quasi-experimental design with archival data was used for students who enrolled in, and graduated from, a post-secondary institution in the upper Midwest. To be included in the sample, students needed to have completed at least three years of high-school mathematics. A generalized linear mixed model was used with students nested within high schools. The data were cross-sectional. Results: High-school predictors were not found to have a significant impact on the completion of a STEM major. Significant student-level predictors included ACT mathematics score, gender and high-school mathematics GPA. Conclusions: The results provide evidence that on average students are equally prepared for the rigorous mathematics coursework regardless of the high-school mathematics curriculum they completed.
Directory of Open Access Journals (Sweden)
Karen Bultitude
2009-05-01
Full Text Available Effective training in key communications skills is critical for successful public engagement. However, what are the secrets to designing and delivering an effectual training course? This paper outlines key findings from a research study into communication training programmes for public engagement with STEM (science, technology, engineering and mathematics. The research focused on training in direct communication methods, (as separate from media training and encompassed both trainers and trainees, the latter group spanning across both scientists and explainers. The findings indicated that training courses are effective at increasing involvement in science communication events and trainees feel more confident and able to engage due to training. An interactive style was found to be a key element of training courses. Demonstrations of good practice followed by own performance with feedback were also important, preferably involving a ‘real’ audience. A list of guidelines on best practice has been developed which offers practical advice.
Pohlmeyer, J. V.
2013-01-29
Motivated by experimental work (Miller et al. in Biomaterials 27(10):2213-2221, 2006, 32(11):2775-2785, 2011) we investigate the effect of growth factor driven haptotaxis and proliferation in a perfusion tissue engineering bioreactor, in which nutrient-rich culture medium is perfused through a 2D porous scaffold impregnated with growth factor and seeded with cells. We model these processes on the timescale of cell proliferation, which typically is of the order of days. While a quantitative representation of these phenomena requires more experimental data than is yet available, qualitative agreement with preliminary experimental studies (Miller et al. in Biomaterials 27(10):2213-2221, 2006) is obtained, and appears promising. The ultimate goal of such modeling is to ascertain initial conditions (growth factor distribution, initial cell seeding, etc.) that will lead to a final desired outcome. © 2013 Society for Mathematical Biology.
Challenging assumptions of notational transparency: the case of vectors in engineering mathematics
Craig, Tracy S.
2017-11-01
The notation for vector analysis has a contentious nineteenth century history, with many different notations describing the same or similar concepts competing for use. While the twentieth century has seen a great deal of unification in vector analysis notation, variation still remains. In this paper, the two primary notations used for expressing the components of a vector are discussed in historical and current context. Popular mathematical texts use the two notations as if they are transparent and interchangeable. In this research project, engineering students' proficiency at vector analysis was assessed and the data were analyzed using the Rasch measurement method. Results indicate that the students found items expressed in unit vector notation more difficult than those expressed in parenthesis notation. The expert experience of notation as transparent and unproblematically symbolic of underlying processes independent of notation is shown to contrast with the student experience where the less familiar notation is experienced as harder to work with.
Wei, Xin; Yu, Jennifer W; Shattuck, Paul; McCracken, Mary; Blackorby, Jose
2013-07-01
Little research has examined the popular belief that individuals with an autism spectrum disorder (ASD) are more likely than the general population to gravitate toward science, technology, engineering, and mathematics (STEM) fields. This study analyzed data from the National Longitudinal Transition Study-2, a nationally representative sample of students with an ASD in special education. Findings suggest that students with an ASD had the highest STEM participation rates although their college enrollment rate was the third lowest among 11 disability categories and students in the general population. Disproportionate postsecondary enrollment and STEM participation by gender, family income, and mental functioning skills were found for young adults with an ASD. Educational policy implications are discussed.
Directory of Open Access Journals (Sweden)
Sergio Amat
2015-08-01
Full Text Available The aim of this paper is to present a teaching experience developed in the Polytechnic University of Cartagena and, more specifically, in the subject of Mathematical Methods Applied to Civil Engineering, that belongs to the Master Degree of Paths, Channels and Ports. Our classes were a mix between the traditional system and the new educational system. Moreover, we tried to adapt the evaluation process to the new European Framework for Higher Education. We have used videos developed by us and by students in our classes. We have noticed that the interest and motivation in class has grown. Also the grades have improved. We did a survey during this academic year and the results were strongly positive for both students and teachers.
Experimental study of gas engine driven air to water heat pump in cooling mode
International Nuclear Information System (INIS)
Elgendy, E.; Schmidt, J.
2010-01-01
Nowadays a sustainable development for more efficient use of energy and protection of the environment is of increasing importance. Gas engine heat pumps represent one of the most practicable solutions which offer high energy efficiency and environmentally friendly for heating and cooling applications. In this paper, the performance characteristics of gas engine driven heat pump used in water cooling were investigated experimentally without engine heat recovery. The effects of several important factors (evaporator water inlet temperature, evaporator water volume flow rate, ambient air temperature, and engine speed) on the performance of gas engine driven heat pump were studied in a wide range of operating conditions. The results showed that primary energy ratio of the system increased by 22.5% as evaporator water inlet temperature increased from 13 o C to 24 o C. On the other hand, varying of engine speed from 1300 rpm to 1750 rpm led to decrease in system primary energy ratio by 13%. Maximum primary energy ratio has been estimated with a value of two over a wide range of operating conditions.
Sumi, Yoichi
2014-01-01
This book is about the pattern formation and the evolution of crack propagation in engineering materials and structures, bridging mathematical analyses of cracks based on singular integral equations, to computational simulation of engineering design. The first two parts of this book focus on elasticity and fracture and provide the basis for discussions on fracture morphology and its numerical simulation, which may lead to a simulation-based fracture control in engineering structures. Several design concepts are discussed for the prevention of fatigue and fracture in engineering structures, including safe-life design, fail-safe design, damage tolerant design. After starting with basic elasticity and fracture theories in parts one and two, this book focuses on the fracture morphology that develops due to the propagation of brittle cracks or fatigue cracks. In part three, the mathematical analysis of a curved crack is precisely described, based on the perturbation method. The stability theory of interactive ...
Experimentally-determined external heat loss of automotive gas turbine engine
Meng, P. R.; Wulf, R. F.
1975-01-01
An external heat balance was conducted on a 150 HP two-shaft automotive gas turbine engine. The engine was enclosed in a calorimeter box and the temperature change of cooling air passing through the box was measured. Cooling airflow ranges of 1.6 to 2.1 lb-per-second and 0.8 to 1.1 lb-per-second were used. The engine housing heat loss increased as the cooling airflow through the calorimeter box was increased, as would be the case in a moving automobile. The heat balance between the total energy input and the sum of shaft power output and various losses compared within 30 percent at engine idle speeds and within 7 percent at full power.
Thermodynamic analysis of the heat regenerative cycle in porous medium engine
International Nuclear Information System (INIS)
Liu Hongsheng; Xie Maozhao; Wu Dan
2009-01-01
The advantages of homogeneous combustion in internal combustion engines are well known all over the world. Recent years, porous medium (PM) engine has been proposed as a new type engine based on the technique of combustion in porous medium, which can fulfils all requirements to perform homogeneous combustion. In this paper, working processes of a PM engine are briefly introduced and an ideal thermodynamic model of the PM heat regeneration cycle in PM engine is developed. An expression for the relation between net work output and thermal efficiency is derived for the cycle. In order to evaluate of the cycle, the influences of the expansion ratio, initial temperature and limited temperature on the net work and efficiency are discussed, and the availability terms of the cycle are analyzed. Comparing the PM heat regenerative cycle of the PM engine against Otto cycle and Diesel cycle shows that PM heat regenerative cycle can improve net work output greatly with little drop of efficiency. The aim of this paper is to predict the thermodynamic performance of PM heat regeneration cycle and provide a guide to further investigations of the PM engine
International Nuclear Information System (INIS)
Guzman-Vargas, L; Reyes-Ramirez, I; Sanchez, N
2005-01-01
In a recent paper (Santillan et al 2001 J. Phys. D: Appl. Phys. 34 2068-72) the local stability of a Curzon-Ahlborn-Novikov (CAN) engine with equal conductances in the coupling with thermal baths was analysed. In this work, we present a local stability analysis of an endoreversible engine operating at maximum power output, for common heat transfer laws, and for different heat conductances α and β, in the isothermal couplings of the working substance with the thermal sources T 1 and T 2 (T 1 > T 2 ). We find that the relaxation times, in the cases analysed here, are a function of α, β, the heat capacity C, T 1 and T 2 . Besides, the eigendirections in a phase portrait are also functions of τ = T 1 /T 2 and the ratio β/α. From these findings, phase portraits for the trajectories after a small perturbation over the steady-state values of internal temperatures are presented, for some significant situations. Finally, we discuss the local stability and energetic properties of the endoreversible CAN heat engine
Numerical study of heat transfer and combustion in IC engine with a porous media piston region
International Nuclear Information System (INIS)
Zhou, Lei; Xie, Mao-Zhao; Luo, Kai Hong
2014-01-01
Based on superadiabatic combustion in porous medium (PM), the porous medium engine as a new combustion concept is proposed to achieve high combustion efficiency and low emissions. In this paper, an axisymmetric model with detailed chemistry and two-temperature treatment is implemented into a variant of the KIVA-3V code to simulate the working process of the PM engine. Comparisons with the same engine but without PM are conducted. Temperature evolution of the PM and its effects are discussed in detail. Key factors affecting heat transfer, combustion and emissions of the PM engine, such as porosity, the initial PM temperature and equivalence ratio, are analyzed. The results show that the characteristics of heat transfer, emissions and combustion of the PM engine are superior to the engine without PM, providing valuable support for the PM engine concept. In particular, the PM engine is shown to sustain ultra lean combustion. - Graphical abstract: In the PM engine, a PM reactor is mounted on the piston head as shown in Fig. 1 which shows the schematic diagram of the computational domain. The heat exchange process between PM material and compressed air increases with upward motion of piston at compression stroke. At the TDC, almost all the air is compressed and closed to PM volume, meanwhile, the fuel is injected into PM chamber to achieve homogenization combustion. - Highlights: •Two-temperature treatment studies the working process of the PM engine. •Self-balancing temperature of the PM determines the continued and stable work. •Stronger heat exchange occurs between gas and PM with smaller porosity. •The PM engine can have lower levels of NO x , unburnt HC and CO emissions
The Importance of Thermal Heat Bridges in Civil Engineering
Directory of Open Access Journals (Sweden)
Adriana Tokar
2011-10-01
Full Text Available Based on the heat transfer characteristics of a construction, the expected temperatures along interior surfaces must be evaluated in order to predict (and avoid areas of potential moisture condensation. Beyond preventing damage to building materials caused by mould growth, adequate surface temperatures are also a relevant factor in the thermal comfort of an interior environment. An agreable climate in a room can be obtained, when relative humidity is between 40 and 60%. As the air in a room is warmer, the more vapor can absorb (and vice versa, influencing the thermal comfort index. Heat losses are influenced largely by thermal bridges of construction. The importance of the thermal heat bridges is strongly increasing today. In new developments the thermal optimization of junctions in today common low energy constructions receives very special standing. The subject of avoiding thermal bridges in passive houses became predominant.
International Nuclear Information System (INIS)
Xia, Jiaxi; Wang, Jiangfeng; Lou, Juwei; Zhao, Pan; Dai, Yiping
2016-01-01
Highlights: • A combined cooling and power system was proposed for engine waste heat recovery. • Effects of key parameters on thermodynamic performance of the system were studied. • Exergoeconomic parameter analysis was performed for the system. • A single-objective optimization by means of genetic algorithm was carried out. - Abstract: A combined cooling and power (CCP) system is developed, which comprises a CO 2 Brayton cycle (BC), an organic Rankine cycle (ORC) and an ejector refrigeration cycle for the cascade utilization of waste heat from an internal combustion engine. By establishing mathematical model to simulate the overall system, thermodynamic analysis and exergoeconomic analysis are conducted to examine the effects of five key parameters including the compressor pressure ratio, the compressor inlet temperature, the BC turbine inlet temperature, the ORC turbine inlet pressure and the ejector primary flow pressure on system performance. What’s more, a single-objective optimization by means of genetic algorithm (GA) is carried out to search the optimal system performance from viewpoint of exergoeconomic. Results show that the increases of the BC turbine inlet temperature, the ORC turbine inlet pressure and the ejector primary flow pressure are benefit to both thermodynamic and exergoeconimic performances of the CCP system. However, the rises in compressor pressure ratio and compressor inlet temperature will lead to worse system performances. By the single-objective optimization, the lowest average cost per unit of exergy product for the overall system is obtained.
An analysis of geothermal heating and engineering cost in Tianjin, China
International Nuclear Information System (INIS)
Wang, W.
1990-01-01
Tianjin is a region with fairly rich low-temperature geothermal resources. Its climate and soaring price of raw coals have made geo heating in Tianjin develop rapidly over the past 5 years. The types of heating systems fall into 3 categories and the primary factors for using temperature drop are 5. According to economical analysis, the optimal discharge temperature in the space heating is about 43 degrees C and the minimum discharge temperature 35 degrees C approximately. This paper reports that an analysis of a typical engineering costs involved shows that the advantages of geo space heating are not notable when compared with burning coals. However, to reduce air pollution, the state and general public are ready to support the development of such geothermal wells as deep as 3,000 m for space heating irrespective of their sole engineering costs
Kuvyrkin, G. N.; Savelyeva, I. Y.; Kuvshynnikova, D. A.
2018-04-01
Creation of new materials based on nanotechnology is an important direction of modern materials science development. Materials obtained using nanotechnology can possess unique physical-mechanical and thermophysical properties, allowing their effective use in structures exposed to high-intensity thermomechanical effects. An important step in creation and use of new materials is the construction of mathematical models to describe the behavior of these materials in a wide range of changes under external effects. The model of heat conduction of structural-sensitive materials is considered with regard to the medium nonlocality effects. The relations of the mathematical model include an integral term describing the spatial nonlocality of the medium. A difference scheme, which makes it possible to obtain a numerical solution of the problem of nonstationary heat conduction with regard to the influence of the medium nonlocality on space, has been developed. The influence of the model parameters on the temperature distributions is analyzed.
Analysis and assessment of a new organic Rankine based heat engine system with/without cogeneration
International Nuclear Information System (INIS)
Hogerwaard, Janette; Dincer, Ibrahim; Zamfirescu, Calin
2013-01-01
A low-temperature heat driven heat engine is proposed as a cost-effective system for power and heat production for small scale applications. The external heat source allows flexibility in the design; the system may be coupled with various available renewable sources including biomass/biofuel/biogas combustion, geothermal heat, concentrated solar radiation, and industrial waste heat, by selecting appropriate off-the-shelf components from the HVAC (heating, ventilation, and air conditioning), refrigeration, and automotive industries for use in an ORC (organic Rankine cycle). A theoretical analysis and an experimental study are carried out for an ORC with R134a as the working fluid, utilizing a low-temperature heat source (T source < 150 °C), with focus on the expansion and boiling processes. The complete ORC model is comprised of models for the expander, working fluid pump, boiler, and condenser. Thermodynamic and heat transfer models are developed to calculate the local and averaged heat transfer coefficient of the working fluid throughout the boiling process, based on the geometry of the selected heat exchanger. Data collected for the experimental ORC test bench are used to validate the expander and boiler models. A case study is performed for the proposed ORC, for cogeneration of power and heat in a residential application. The results of the case study analysis for the proposed ORC system indicate a cycle efficiency of 0.05, exergy efficiency of 0.17, and energy and exergy cogeneration efficiency of 0.87, and 0.35, respectively. - Highlights: • Development and investigation of a scroll based Rankine heat engine operating with R134a. • Thermodynamic analyses of the system and its components. • Heat transfer analyses of boiler and condenser. • Dynamic analysis of expander. • Model validation through performed experiments on an ORC test bench
Khudyakova, G. I.; Kozlov, A. N.; Svishchev, D. A.
2017-11-01
The paper is concerned with an integrated system of internal combustion engine and mini combined heat and power plant (ICE-CHP). The system is based on multi-stage wood biomass gasification. The use of producer gas in the system affects negatively the internal combustion engine performance and, therefore, reduces the efficiency of the ICE-CHP plant. A mathematical model of an internal combustion engine running on low-calorie producer gas was developed using an overview of Russian and foreign manufacturers of reciprocating units, that was made in the research. A thermal calculation was done for four-stroke gas engines of different rated power outputs (30, 100 and 250 kW), running on producer gas (CO2 - 10.2, CO - 45.8, N2 - 38.8%). Thermal calculation demonstrates that the engine exhaust gas temperature reaches 500 - 600°C at the rated power level and with the lower engine power, the temperature gets higher. For example, for an internal combustion engine power of 1000 kW the temperature of exhaust gases equals 400°C. A comparison of the efficiency of engine operation on natural gas and producer gas shows that with the use of producer gas the power output declines from 300 to 250 kWe. The reduction in the effective efficiency in this case makes up 2%. The measures are proposed to upgrade the internal combustion engine to enable it to run on low-calorie producer gas.
Physical principle and engineering features of the deep pool reactor for residential heating
International Nuclear Information System (INIS)
Shi Gong; Zhao Zhaoyi; Guo Jingren; Tian Jiafu
1999-01-01
The use of nuclear energy for low temperature heating is confronted with challenges of safety and economy. The deep pool reactor, a low temperature heating reactor based on novel design principles, has been studied in detail. Results show that it has excellent safety and economic features, and is very suitable for low temperature heating purposes. The whole heating system including the nuclear reactor will be a simple and easy engineering system with the characteristics of reliability, safety and economy because the system and all its devices are based on low temperature and ordinary pressure
Kalevitch, Maria; Maurer, Cheryl; Badger, Paul; Holdan, Greg; Sirinterlikci, Arif
2015-01-01
The School of Engineering, Mathematics, and Science (SEMS) at Robert Morris University (RMU) was awarded a five-year grant from the National Science Foundation (NSF) to fund scholarships to 21 academically talented but financially challenged students majoring in the disciplines of science, technology, engineering, and mathematics (STEM). Each…
Dotson, Daniel S.; Franks, Tina P.
2015-01-01
More than 53,000 citations from 609 dissertations published at The Ohio State University between 1998-2012 representing four science disciplines--civil engineering, computer science, mathematics and physics--were examined to determine what, if any, preferences or trends exist. This case study seeks to identify whether or not researcher preferences…
Taljaard, Johann
2016-01-01
This article reviews the literature on multi-sensory technology and, in particular, looks at answering the question: "What multi-sensory technologies are available to use in a science, technology, engineering, arts and mathematics (STEAM) classroom, and do they affect student engagement and learning outcomes?" Here engagement is defined…
Gilmore, Joanna; Maher, Michelle A.; Feldon, David F.; Timmerman, Briana
2014-01-01
Research indicates that modifying teachers' beliefs about learning and teaching (i.e. teaching orientation) may be a prerequisite to changing their teaching practices. This mixed methods study quantitized data from interviews with 65 graduate teaching assistants (GTAs) from science, technology, engineering, and mathematics (STEM) fields to assess…
Butkovich, Nancy J.
2015-01-01
Doctoral candidates may request short-term embargoes on the release of their dissertations in order to apply for patents. This study examines how often inventions described in dissertations in chemical engineering, chemistry, physics, and mathematics are converted into U.S. patent applications, as well as the relationship between dissertation…