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Sample records for mechanical engineers boston

  1. Mechanical engineering

    CERN Document Server

    Darbyshire, Alan

    2010-01-01

    Alan Darbyshire's best-selling text book provides five-star high quality content to a potential audience of 13,000 engineering students. It explains the most popular specialist units of the Mechanical Engineering, Manufacturing Engineering and Operations & Maintenance Engineering pathways of the new 2010 BTEC National Engineering syllabus. This challenging textbook also features contributions from specialist lecturers, ensuring that no stone is left unturned.

  2. Engineering mechanics

    CERN Document Server

    Gross, Dietmar; Schröder, Jörg; Wall, Wolfgang A; Rajapakse, Nimal

    Statics is the first volume of a three-volume textbook on Engineering Mechanics. The authors, using a time-honoured straightforward and flexible approach, present the basic concepts and principles of mechanics in the clearest and simplest form possible to advanced undergraduate engineering students of various disciplines and different educational backgrounds. An important objective of this book is to develop problem solving skills in a systematic manner. Another aim of this volume is to provide engineering students as well as practising engineers with a solid foundation to help them bridge the gap between undergraduate studies on the one hand and advanced courses on mechanics and/or practical engineering problems on the other. The book contains numerous examples, along with their complete solutions. Emphasis is placed upon student participation in problem solving. The contents of the book correspond to the topics normally covered in courses on basic engineering mechanics at universities and colleges. Now in i...

  3. Mechanical engineering

    International Nuclear Information System (INIS)

    1988-01-01

    The Mechanical Engineering Division provides the other NAC divisions with design and construction services. Items of special mechanical significance are discussed here. The projects which received major design attention during the past year were: a coupling capacitor for SPC2; a bending magnet and solenoid for ECR ion source; a scanner for outer orbits of the SSC; a scattering chamber for an experimental beamline; a beam swinger; a rotary target magazine for isotope production; a robot arm for isotope production; an isotope transport system and a target cooling system for isotope production. The major projects that were under construction are: a magnetic spectrometer; a second injector cyclotron (SPC2) and extensions to the high-energy beamlines. 4 figs

  4. Mechanical engineer's handbook

    CERN Document Server

    Marghitu, Dan B

    2001-01-01

    The Mechanical Engineer's Handbook was developed and written specifically to fill a need for mechanical engineers and mechanical engineering students throughout the world. With over 1000 pages, 550 illustrations, and 26 tables the Mechanical Engineer's Handbook is very comprehensive, yet affordable, compact, and durable. The Handbook covers all major areas of mechanical engineering with succinct coverage of the definitions, formulas, examples, theory, proofs, and explanations of all principle subject areas. The Handbook is an essential, practical companion for all mechanic

  5. Mechanical engineering education

    CERN Document Server

    Davim, J Paulo

    2012-01-01

    Mechanical Engineering is defined nowadays as a discipline "which involves the application of principles of physics, design, manufacturing and maintenance of mechanical systems". Recently, mechanical engineering has also focused on some cutting-edge subjects such as nanomechanics and nanotechnology, mechatronics and robotics, computational mechanics, biomechanics, alternative energies, as well as aspects related to sustainable mechanical engineering.This book covers mechanical engineering higher education with a particular emphasis on quality assurance and the improvement of academic

  6. Tokamak engineering mechanics

    CERN Document Server

    Song, Yuntao; Du, Shijun

    2013-01-01

    Tokamak Engineering Mechanics offers concise and thorough coverage of engineering mechanics theory and application for tokamaks, and the material is reinforced by numerous examples. Chapter topics include general principles, static mechanics, dynamic mechanics, thermal fluid mechanics and multiphysics structural mechanics of tokamak structure analysis. The theoretical principle of the design and the methods of the analysis for various components and load conditions are presented, while the latest engineering technologies are also introduced. The book will provide readers involved in the study

  7. Tokamak engineering mechanics

    International Nuclear Information System (INIS)

    Song, Yuntao; Wu, Weiyue; Du, Shijun

    2014-01-01

    Provides a systematic introduction to tokamaks in engineering mechanics. Includes design guides based on full mechanical analysis, which makes it possible to accurately predict load capacity and temperature increases. Presents comprehensive information on important design factors involving materials. Covers the latest advances in and up-to-date references on tokamak devices. Numerous examples reinforce the understanding of concepts and provide procedures for design. Tokamak Engineering Mechanics offers concise and thorough coverage of engineering mechanics theory and application for tokamaks, and the material is reinforced by numerous examples. Chapter topics include general principles, static mechanics, dynamic mechanics, thermal fluid mechanics and multiphysics structural mechanics of tokamak structure analysis. The theoretical principle of the design and the methods of the analysis for various components and load conditions are presented, while the latest engineering technologies are also introduced. The book will provide readers involved in the study of mechanical/fusion engineering with a general understanding of tokamak engineering mechanics.

  8. Mechanical engineers' handbook, materials and engineering mechanics

    CERN Document Server

    Kutz, Myer

    2015-01-01

    Full coverage of materials and mechanical design inengineering Mechanical Engineers' Handbook, Fourth Edition provides aquick guide to specialized areas you may encounter in your work,giving you access to the basics of each and pointing you towardtrusted resources for further reading, if needed. The accessibleinformation inside offers discussions, examples, and analyses ofthe topics covered. This first volume covers materials and mechanical design, givingyou accessible and in-depth access to the most common topics you'llencounter in the discipline: carbon and alloy steels, stainlesssteels, a

  9. Mechanical engineers data handbook

    CERN Document Server

    Carvill, James

    1994-01-01

    This text provides the student and professional mechanical engineer with a reference text of an essentially practical nature. It is uncluttered by text, and extensive use of illustrations and tables provide quick and clear access to information. It alsoincludes examples of detailed calculations on many of the applications of technology used by mechanical and production engineers, draughtsmen and engineering designers.Although mainly intended for those studying and practising mechanical engineering, a glance at the contents will show that it is also useful to those in related br

  10. Mechanical design engineering handbook

    CERN Document Server

    Childs, Peter R N

    2013-01-01

    Mechanical Design Engineering Handbook is a straight-talking and forward-thinking reference covering the design, specification, selection, use and integration of machine elements fundamental to a wide range of engineering applications. Develop or refresh your mechanical design skills in the areas of bearings, shafts, gears, seals, belts and chains, clutches and brakes, springs, fasteners, pneumatics and hydraulics, amongst other core mechanical elements, and dip in for principles, data and calculations as needed to inform and evaluate your on-the-job decisions. Covering the full spectrum

  11. Engineering quantum mechanics

    CERN Document Server

    Ahn, Doyeol

    2011-01-01

    A clear introduction to quantum mechanics concepts Quantum mechanics has become an essential tool for modern engineering, particularly due to the recent developments in quantum computing as well as the rapid progress in optoelectronic devices. Engineering Quantum Mechanics explains the fundamentals of this exciting field, providing broad coverage of both traditional areas such as semiconductor and laser physics as well as relatively new yet fast-growing areas such as quantum computation and quantum information technology. The book begins with basic quantum mechanics, reviewing measurements and probability, Dirac formulation, the uncertainty principle, harmonic oscillator, angular momentum eigenstates, and perturbation theory. Then, quantum statistical mechanics is explored, from second quantization and density operators to coherent and squeezed states, coherent interactions between atoms and fields, and the Jaynes-Cummings model. From there, the book moves into elementary and modern applications, discussing s...

  12. Mechanical engineer's reference book

    CERN Document Server

    Parrish, A

    1973-01-01

    Mechanical Engineer's Reference Book: 11th Edition presents a comprehensive examination of the use of Systéme International d' Unités (SI) metrication. It discusses the effectiveness of such a system when used in the field of engineering. It addresses the basic concepts involved in thermodynamics and heat transfer. Some of the topics covered in the book are the metallurgy of iron and steel; screw threads and fasteners; hole basis and shaft basis fits; an introduction to geometrical tolerancing; mechanical working of steel; high strength alloy steels; advantages of making components as castings

  13. Mechanical engineering principles

    CERN Document Server

    Bird, John

    2014-01-01

    A student-friendly introduction to core engineering topicsThis book introduces mechanical principles and technology through examples and applications, enabling students to develop a sound understanding of both engineering principles and their use in practice. These theoretical concepts are supported by 400 fully worked problems, 700 further problems with answers, and 300 multiple-choice questions, all of which add up to give the reader a firm grounding on each topic.The new edition is up to date with the latest BTEC National specifications and can also be used on undergraduate courses in mecha

  14. Game mechanics engine

    OpenAIRE

    Magnusson, Lars V

    2011-01-01

    Game logic and game rules exists in all computer games, but they are created di erently for all game engines. This game engine dependency exists because of how the internal object model is implemented in the engine, as a place where game logic data is intermingled with the data needed by the low- level subsystems. This thesis propose a game object model design, based on existing theory, that removes this dependency and establish a general game logic framework. The thesis the...

  15. Diesel Engine Mechanics.

    Science.gov (United States)

    Foutes, William A.

    Written in student performance terms, this curriculum guide on diesel engine repair is divided into the following eight sections: an orientation to the occupational field and instructional program; instruction in operating principles; instruction in engine components; instruction in auxiliary systems; instruction in fuel systems; instruction in…

  16. System dynamics for mechanical engineers

    CERN Document Server

    Davies, Matthew

    2015-01-01

    This textbook is ideal for mechanical engineering students preparing to enter the workforce during a time of rapidly accelerating technology, where they will be challenged to join interdisciplinary teams. It explains system dynamics using analogies familiar to the mechanical engineer while introducing new content in an intuitive fashion. The fundamentals provided in this book prepare the mechanical engineer to adapt to continuous technological advances with topics outside traditional mechanical engineering curricula by preparing them to apply basic principles and established approaches to new problems. This book also: ·         Reinforces the connection between the subject matter and engineering reality ·         Includes an instructor pack with the online publication that describes in-class experiments with minimal preparation requirements ·         Provides content dedicated to the modeling of modern interdisciplinary technological subjects, including opto-mechanical systems, high...

  17. Springer handbook of mechanical engineering

    Energy Technology Data Exchange (ETDEWEB)

    Grote, Karl-Heinrich [Magdeburg Univ. (Germany). Dept. of Mechanical Engineering; Antonsson, Erik K. (eds.) [California Inst. of Technology (CALTEC), Pasadena, CA (United States). Dept. of Mechanical Engineering

    2009-07-01

    Mechanical Engineering is a professional engineering discipline which involves the application of principles of physics, design, manufacturing and maintenance of mechanical systems. It requires a solid understanding of the key concepts including mechanics, kinematics, thermodynamics and energy. Mechanical engineers use these principles and others in the design and analysis of automobiles, aircrafts, heating and cooling systems, industrial equipment and machinery. In addition to these main areas, specialized fields are necessary to prepare future engineers for their positions in industry, such as mechatronics and robotics, transportation and logistics, fuel technology, automotive engineering, biomechanics, vibration, optics and others. Accordingly, the Springer Handbook of Mechanical Engineering devotes its contents to all areas of interest for the practicing engineer as well as for the student at various levels and educational institutions. Authors from all over the world have contributed with their expertise and support the globally working engineer in finding a solution for today's mechanical engineering problems. Each subject is discussed in detail and supported by numerous figures and tables. DIN standards are retained throughout and ISO equivalents are given where possible. The text offers a concise but detailed and authoritative treatment of the topics with full references. (orig.)

  18. Mechanical Material Engineering

    International Nuclear Information System (INIS)

    Kim, Mun Il

    1993-01-01

    This book introduced mechanical material with introduction, basic problems about metal ingredient of machine of metal and alloy, property of metal material mechanical metal material such as categorization of metal material and high tensile structure steel, mechanic design and steel material with three important points on using of steel materials, selection and directions machine structural steel, selection and directions of steel for tool, selection and instruction of special steel like stainless steel and spring steel, nonferrous metal materials and plastic.

  19. Mechanical Engineering Department Technical Review

    International Nuclear Information System (INIS)

    Carr, R.B.; Denney, R.M.

    1981-01-01

    The Mechanical Engineering Department Technical Review is published to inform readers of various technical activities within the Department, promote exchange of ideas, and give credit to personnel who are achieving the results. The report is presented in two parts: technical achievements and publication abstracts. The first is divided into seven sections, each of which reports on an engineering division and its specific activities related to nuclear tests, nuclear explosives, weapons, energy systems, engineering sciences, magnetic fusion, and materials fabrication

  20. Mechanical Engineering Department technical abstracts

    International Nuclear Information System (INIS)

    1984-01-01

    The Mechanical Engineering Department publishes abstracts twice a year to inform readers of the broad range of technical activities in the Department, and to promote an exchange of ideas. Details of the work covered by an abstract may be obtained by contacting the author(s). General information about the current role and activities of each of the Department's seven divisions precedes the technical abstracts. Further information about a division's work may be obtained from the division leader, whose name is given at the end of each divisional summary. The Department's seven divisions are as follows: Nuclear Test Engineering Division, Nuclear Explosives Engineering Division, Weapons Engineering Division, Energy Systems Engineering Division, Engineering Sciences Division, Magnetic Fusion Engineering Division and Materials Fabrication Division

  1. The Stirling engine mechanism optimization

    Directory of Open Access Journals (Sweden)

    Jiří Podešva

    2016-03-01

    Full Text Available A special type of the gas engine with external combustion is called Stirling engine. The mechanism has two pistons with two volumes inside. The pistons are connected together through cooler, regenerator and warmer. The engine effectivity depends on the piston movement behaviour. The usual sinusoidal time curve leads to low effectiveness. The quick movement from lower to upper position with a certain delay in both top and bottom dead centres is more effective. The paper deals with three types of mechanisms, analyzing the piston movement, and their behavior. Special emphasize is taken to the piston movement regime.

  2. Handbook of mechanical engineering terms

    CERN Document Server

    Ramalingam, KK

    2009-01-01

    About the Book: The Handbook of Mechanical Engineering terms contains short, precise definitions of about four thousand terms. These terms have been collected from different sources, edited and grouped under twenty six parts and given alphabetically under each part for easy reference. The book will be a source of guidance and help to the students, staff and practising engineers in understanding and updating the subject matter. Contents: The Handbook of Mechanical Engineering terms contains short, precise definitions of about four thousand terms. These terms have been collected from differ

  3. Mechanical Engineering | Classification | College of Engineering & Applied

    Science.gov (United States)

    Engineering Concentration on Ergonomics M.S. Program in Computer Science Interdisciplinary Concentration on Energy Doctoral Programs in Engineering Non-Degree Candidate Departments Biomedical Engineering Biomedical Engineering Industry Advisory Council Civil & Environmental Engineering Civil &

  4. Basic Mechanics with Engineering Applications

    CERN Document Server

    Jones, J; Fawcett, J N

    2012-01-01

    This book gives a sufficient grounding in mechanics for engineers to tackle a significant range of problems encountered in the design and specification of simple structures and machines. It also provides an excellent background for students wishing to progress to more advanced studies in three-dimensional mechanics.

  5. 77 FR 50916 - Safety Zone; Boston Harbor's Rock Removal Project, Boston Inner Harbor, Boston, MA

    Science.gov (United States)

    2012-08-23

    ... operation on the navigable waters of Boston Inner Harbor, in the main ship channel near Castle Island. This... operations in support of the U.S. Army Corps of Engineers rock removal project. Entering into, transiting... before the start date of the project. The U.S. Army Corps of Engineers also discussed the rock removal...

  6. Continuum mechanics for engineers

    CERN Document Server

    Mase, G Thomas; Mase, George E

    2009-01-01

    Continuum TheoryContinuum MechanicsStarting OverNotationEssential MathematicsScalars, Vectors and Cartesian TensorsTensor Algebra in Symbolic Notation - Summation ConventionIndicial NotationMatrices and DeterminantsTransformations of Cartesian TensorsPrincipal Values and Principal DirectionsTensor Fields, Tensor CalculusIntegral Theorems of Gauss and StokesStress PrinciplesBody and Surface Forces, Mass DensityCauchy Stress PrincipleThe Stress TensorForce and Moment Equilibrium; Stress Tensor SymmetryStress Transformation LawsPrincipal Stresses; Principal Stress DirectionsMaximum and Minimum Stress ValuesMohr's Circles For Stress Plane StressDeviator and Spherical Stress StatesOctahedral Shear StressKinematics of Deformation and MotionParticles, Configurations, Deformations and MotionMaterial and Spatial CoordinatesLangrangian and Eulerian DescriptionsThe Displacement FieldThe Material DerivativeDeformation Gradients, Finite Strain TensorsInfinitesimal Deformation TheoryCompatibility EquationsStretch RatiosRot...

  7. Mechanics of composite materials - 1983. Proceedings of the Symposium, Boston, MA, November 13-18, 1983

    International Nuclear Information System (INIS)

    Dvorak, G.J.

    1983-01-01

    The present conference discusses plate theories applicable to laminated composites, the analysis of large deformations in layered composite shells, composite plate nonlinear bending effects, hybrid composite constitutive behavior, polymeric material life prediction by means of kinetic fracture mechanics, and crack growth direction in fibrous composites. Also discussed are stress singularities and solution structures, together with the delamination behavior and fracture mechanics parameters, of delamination mechanics in fiber-reinforced composites, followed by the theory and applications of unidirectional composite fracture, impact and fatigue behavior in graphite-epoxy laminates, and the fracture behavior of notched unidirectional boron/aluminum composite laminates

  8. Hamiltonian mechanics limits microscopic engines

    Science.gov (United States)

    Anglin, James; Gilz, Lukas; Thesing, Eike

    2015-05-01

    We propose a definition of fully microscopic engines (micro-engines) in terms of pure mechanics, without reference to thermodynamics, equilibrium, or cycles imposed by external control, and without invoking ergodic theory. This definition is pragmatically based on the observation that what makes engines useful is energy transport across a large ratio of dynamical time scales. We then prove that classical and quantum mechanics set non-trivial limits-of different kinds-on how much of the energy that a micro-engine extracts from its fuel can be converted into work. Our results are not merely formal; they imply manageable design constraints on micro-engines. They also suggest the novel possibility that thermodynamics does not emerge from mechanics in macroscopic regimes, but rather represents the macroscopic limit of a generalized theory, valid on all scales, which governs the important phenomenon of energy transport across large time scale ratios. We propose experimental realizations of the dynamical mechanisms we identify, with trapped ions and in Bose-Einstein condensates (``motorized bright solitons'').

  9. Modern mechanical engineering research, development and education

    CERN Document Server

    2014-01-01

    This book covers modern subjects of mechanical engineering such as nanomechanics and nanotechnology, mechatronics and robotics, computational mechanics, biomechanics, alternative energies, sustainability as well as all aspects related with mechanical engineering education. The chapters help enhance the understanding of both the fundamentals of mechanical engineering and its application to the solution of problems in modern industry. This book is suitable for students, both in final undergraduate mechanical engineering courses or at the graduate level. It also serves as a useful reference for academics, mechanical engineering researchers, mechanical, materials and manufacturing engineers, professionals in related with mechanical engineering.

  10. Quantum Mechanics for Electrical Engineers

    CERN Document Server

    Sullivan, Dennis M

    2011-01-01

    The main topic of this book is quantum mechanics, as the title indicates.  It specifically targets those topics within quantum mechanics that are needed to understand modern semiconductor theory.   It begins with the motivation for quantum mechanics and why classical physics fails when dealing with very small particles and small dimensions.  Two key features make this book different from others on quantum mechanics, even those usually intended for engineers:   First, after a brief introduction, much of the development is through Fourier theory, a topic that is at

  11. Engineering science and mechanics department head named

    OpenAIRE

    Nystrom, Lynn A.

    2004-01-01

    Ishwar K. Puri, professor of mechanical engineering and executive associate dean of engineering at the University of Illinois at Chicago, will become the head of Virginia Tech•À_ó»s Department of Engineering Science and Mechanics Aug. 1.

  12. Perspectives of ukrainian mechanical engineering development

    OpenAIRE

    Dyrda, E.; Schepetkova, A.; Galushko, O.

    2013-01-01

    Theses are devoted to problems and perspectives of Ukrainian mechanical engineering development. Role of mechanical engineering in national economy is described. Problems of mechanical engineering, such as losing the cometetive advantages, production decreasing, debts growing, ineffective assets structure, are investigated. Influence of European integration process on mechanical engineering enterprises is discussed.

  13. Mechanical engineering department technical review

    International Nuclear Information System (INIS)

    Carr, R.B.; Denney, R.M.

    1981-01-01

    The Mechanical Engineering Department Technical Review is published to: (1) inform the readers of various technical activities within the department, (2) promote exchange of ideas, and (3) give credit to the personnel who are achieving the results. The report is formatted into two parts: technical acievements and publication abstracts. The first is divided into eight sections, one for each division in the department providing the reader with the names of the personnel and the division accomplishing the work

  14. Mechanical Engineering Department. Technical review

    Energy Technology Data Exchange (ETDEWEB)

    Simecka, W.B.; Condouris, R.A.; Talaber, C. (eds.)

    1980-01-01

    The Mechanical Engineering Department Technical Review is published to (1) inform the readers of various technical activities within the Department, (2) promote exchange of ideas, and (3) give credit to the personnel who are achieving the results. The report is formatted into two parts: technical achievements and publication abstracts. The first is divided into eight sections, one for each Division in the Department providing the reader with the names of the personnel and the Division accomplishing the work.

  15. Mechanical Engineering Department technical abstracts

    International Nuclear Information System (INIS)

    Denney, R.M.

    1982-01-01

    The Mechanical Engineering Department publishes listings of technical abstracts twice a year to inform readers of the broad range of technical activities in the Department, and to promote an exchange of ideas. Details of the work covered by an abstract may be obtained by contacting the author(s). Overall information about current activities of each of the Department's seven divisions precedes the technical abstracts

  16. Mechanical Engineering Department. Technical review

    International Nuclear Information System (INIS)

    Simecka, W.B.; Condouris, R.A.; Talaber, C.

    1980-01-01

    The Mechanical Engineering Department Technical Review is published to (1) inform the readers of various technical activities within the Department, (2) promote exchange of ideas, and (3) give credit to the personnel who are achieving the results. The report is formatted into two parts: technical achievements and publication abstracts. The first is divided into eight sections, one for each Division in the Department providing the reader with the names of the personnel and the Division accomplishing the work

  17. A brief history of mechanical engineering

    CERN Document Server

    Dixit, Uday Shanker; Davim, J Paulo

    2017-01-01

    What is mechanical engineering? What a mechanical engineering does? How did the mechanical engineering change through ages? What is the future of mechanical engineering? This book answers these questions in a lucid manner. It also provides a brief chronological history of landmark events and answers questions such as: When was steam engine invented? Where was first CNC machine developed? When did the era of additive manufacturing start? When did the marriage of mechanical and electronics give birth to discipline of mechatronics? This book informs and create interest on mechanical engineering in the general public and particular in students. It also helps to sensitize the engineering fraternity about the historical aspects of engineering. At the same time, it provides a common sense knowledge of mechanical engineering in a handy manner.

  18. SMAP Instrument Mechanical System Engineering

    Science.gov (United States)

    Slimko, Eric; French, Richard; Riggs, Benjamin

    2013-01-01

    The Soil Moisture Active Passive (SMAP) mission, scheduled for launch by the end of 2014, is being developed to measure the soil moisture and soil freeze/thaw state on a global scale over a three-year period. The accuracy, resolution, and global coverage of SMAP measurements are invaluable across many science and applications disciplines including hydrology, climate, carbon cycle, and the meteorological, environment, and ecology applications communities. The SMAP observatory is composed of a despun bus and a spinning instrument platform that includes both a deployable 6 meter aperture low structural frequency Astromesh reflector and a spin control system. The instrument section has engendered challenging mechanical system issues associated with the antenna deployment, flexible antenna pointing in the context of a multitude of disturbances, spun section mass properties, spin control system development, and overall integration with the flight system on both mechanical and control system levels. Moreover, the multitude of organizations involved, including two major vendors providing the spin subsystem and reflector boom assembly plus the flight system mechanical and guidance, navigation, and control teams, has led to several unique system engineering challenges. Capturing the key physics associated with the function of the flight system has been challenging due to the many different domains that are applicable. Key interfaces and operational concepts have led to complex negotiations because of the large number of organizations that integrate with the instrument mechanical system. Additionally, the verification and validation concerns associated with the mechanical system have had required far-reaching involvement from both the flight system and other subsystems. The SMAP instrument mechanical systems engineering issues and their solutions are described in this paper.

  19. Expose Mechanical Engineering Students to Biomechanics Topics

    Science.gov (United States)

    Shen, Hui

    2011-01-01

    To adapt the focus of engineering education to emerging new industries and technologies nationwide and in the local area, a biomechanics module has been developed and incorporated into a mechanical engineering technical elective course to expose mechanical engineering students at ONU (Ohio Northern University) to the biomedical engineering topics.…

  20. Standardized Curriculum for Diesel Engine Mechanics.

    Science.gov (United States)

    Mississippi State Dept. of Education, Jackson. Office of Vocational, Technical and Adult Education.

    Standardized curricula are provided for two courses for the secondary vocational education program in Mississippi: diesel engine mechanics I and II. The eight units in diesel engine mechanics I are as follows: orientation; shop safety; basic shop tools; fasteners; measurement; engine operating principles; engine components; and basic auxiliary…

  1. Mechanical Engineering Department technical review

    Energy Technology Data Exchange (ETDEWEB)

    Carr, R.B.; Abrahamson, L.; Denney, R.M.; Dubois, B.E (eds.)

    1982-01-01

    Technical achievements and publication abstracts related to research in the following Divisions of Lawrence Livermore Laboratory are reported in this biannual review: Nuclear Fuel Engineering; Nuclear Explosives Engineering; Weapons Engineering; Energy Systems Engineering; Engineering Sciences; Magnetic Fusion Engineering; and Material Fabrication. (LCL)

  2. Technical abstracts: Mechanical engineering, 1990

    International Nuclear Information System (INIS)

    Broesius, J.Y.

    1991-01-01

    This document is a compilation of the published, unclassified abstracts produced by mechanical engineers at Lawrence Livermore National Laboratory (LLNL) during the calendar year 1990. Many abstracts summarize work completed and published in report form. These are UCRL-JC series documents, which include the full text of articles to be published in journals and of papers to be presented at meetings, and UCID reports, which are informal documents. Not all UCIDs contain abstracts: short summaries were generated when abstracts were not included. Technical Abstracts also provides descriptions of those documents assigned to the UCRL-MI (miscellaneous) category. These are generally viewgraphs or photographs presented at meetings. An author index is provided at the back of this volume for cross referencing

  3. Korean society of mechanical engineers 60 years

    International Nuclear Information System (INIS)

    2005-12-01

    This book introduces 60 years of Korean society of mechanical engineers with birth, foundation, development process, change of enforcement regulation and articles of association, important data of this association, 60 years of parts, committee and branch, business of association like academic event, publication, technical development business, supporting research centers, bond Korean society of mechanical engineers and mechanical industry and development of related organizations, development for industrial fields and development direction of Korean society of mechanical engineers.

  4. An introduction to mechanical engineering, pt.2

    CERN Document Server

    Clifford, Michael

    2010-01-01

    An Introduction to Mechanical Engineering: Part 2 is an essential text for all second-year undergraduate students as well as those studying foundation degrees and HNDs. The text provides thorough coverage of the following core engineering topics:Fluid dynamicsThermodynamicsSolid mechanicsControl theory and techniquesMechanical power, loads and transmissionsStructural vibrationAs well as mechanical engineers, the text will be highly relevant to automotive, aeronautical/aerospace and general engineering students.The material in this book has full student and lecturer support on an accompanying w

  5. Deformation and fracture mechanics of engineering materials

    National Research Council Canada - National Science Library

    Hertzberg, Richard W; Vinci, Richard Paul; Hertzberg, Jason L

    2012-01-01

    "Hertzberg's 5th edition of Deformation & Fracture Mechanics of Engineering Materials offers several new features including a greater number and variety of homework problems using more computational software...

  6. An introduction to mechanical engineering, pt.1

    CERN Document Server

    Clifford, Michael; Shipway, Philip

    2012-01-01

    An Introduction to Mechanical Engineering is an essential text for all first-year undergraduate students as well as those studying for foundation degrees and HNDs. The text gives a thorough grounding in the following core engineering topics: thermodynamics, fluid mechanics, solid mechanics, dynamics, electricals and electronics, and materials science. As well as mechanical engineers, the text will be highly relevant to civil, automotive, aeronautical/aerospace and general engineering students.The text is written by an experienced team of first-year lecturers at the internationally renowned Uni

  7. Teaching Continuum Mechanics in a Mechanical Engineering Program

    Science.gov (United States)

    Liu, Yucheng

    2011-01-01

    This paper introduces a graduate course, continuum mechanics, which is designed for and taught to graduate students in a Mechanical Engineering (ME) program. The significance of continuum mechanics in engineering education is demonstrated and the course structure is described. Methods used in teaching this course such as topics, class…

  8. Mechanical engineering science in SI units

    CERN Document Server

    Gwyther, J L; Williams, G

    1970-01-01

    0.1 Mechanical Engineering Science covers various fundamental concepts that are essential in the practice of mechanical engineering. The title is comprised of 19 chapters that detail various topics, including chemical and physical laws. The coverage of the book includes Newtonian laws, mechanical energy, friction, stress, and gravity. The text also discusses the chemical aspects of mechanical engineering, which include gas laws, states of matter, and fuel combustion. The last chapter tackles concerns in laboratory experiments. The book will be of great use to students of mechanical eng

  9. Gasoline Engine Mechanics. Florida Vocational Program Guide.

    Science.gov (United States)

    University of South Florida, Tampa. Dept. of Adult and Vocational Education.

    This vocational program guide is intended to assist in the organization, operation, and evaluation of a program in gasoline engine mechanics in school districts, area vocational centers, and community colleges. The following topics are covered: job duties of small-engine mechanics; program content (curriculum framework and student performance…

  10. Introductory Education for Mechanical Engineering by Exercise in Mechanical Disassembly

    Science.gov (United States)

    Matsui, Yoshio; Asakawa, Naoki; Iwamori, Satoru

    An introductory program “Exercise for engineers in mechanical disassembly” is an exercise that ten students of every team disassemble a motor scooter to the components and then assemble again to the initial form in 15 weeks. The purpose of this program is to introduce mechanical engineering by touching the real machine and learning how it is composed from various mechanical parts to the students at the early period after the entrance into the university. Additional short lectures by young teachers and a special lecture by a top engineer in the industry encourage the students to combine the actual machine and the mechanical engineering subjects. Furthermore, various educations such as group leader system, hazard prediction training, parts filing are included in this program. As a result, students recognize the importance of the mechanical engineering study and the way of group working.

  11. Selection of software for mechanical engineering undergraduates

    International Nuclear Information System (INIS)

    Cheah, C. T.; Yin, C. S.; Halim, T.; Naser, J.; Blicblau, A. S.

    2016-01-01

    A major problem with the undergraduate mechanical course is the limited exposure of students to software packages coupled with the long learning curve on the existing software packages. This work proposes the use of appropriate software packages for the entire mechanical engineering curriculum to ensure students get sufficient exposure real life design problems. A variety of software packages are highlighted as being suitable for undergraduate work in mechanical engineering, e.g. simultaneous non-linear equations; uncertainty analysis; 3-D modeling software with the FEA; analysis tools for the solution of problems in thermodynamics, fluid mechanics, mechanical system design, and solid mechanics.

  12. Selection of software for mechanical engineering undergraduates

    Energy Technology Data Exchange (ETDEWEB)

    Cheah, C. T.; Yin, C. S.; Halim, T.; Naser, J.; Blicblau, A. S., E-mail: ablicblau@swin.edu.au [Swinburne University of Technology, Faculty of Science Engineering and Technology, PO Box 218 Hawthorn, Victoria, Australia, 3122 (Australia)

    2016-07-12

    A major problem with the undergraduate mechanical course is the limited exposure of students to software packages coupled with the long learning curve on the existing software packages. This work proposes the use of appropriate software packages for the entire mechanical engineering curriculum to ensure students get sufficient exposure real life design problems. A variety of software packages are highlighted as being suitable for undergraduate work in mechanical engineering, e.g. simultaneous non-linear equations; uncertainty analysis; 3-D modeling software with the FEA; analysis tools for the solution of problems in thermodynamics, fluid mechanics, mechanical system design, and solid mechanics.

  13. Mechanical engineers' handbook, design, instrumentation, and controls

    CERN Document Server

    Kutz, Myer

    2015-01-01

    Full coverage of electronics, MEMS, and instrumentation andcontrol in mechanical engineering This second volume of Mechanical Engineers' Handbookcovers electronics, MEMS, and instrumentation and control, givingyou accessible and in-depth access to the topics you'll encounterin the discipline: computer-aided design, product design formanufacturing and assembly, design optimization, total qualitymanagement in mechanical system design, reliability in themechanical design process for sustainability, life-cycle design,design for remanufacturing processes, signal processing, dataacquisition and dis

  14. Fluid mechanics for engineers. A graduate textbook

    Energy Technology Data Exchange (ETDEWEB)

    Schobeiri, Meinhard T. [Texas A and M Univ., College Station, TX (United States). Dept. of Mechanical Engineering

    2010-07-01

    The contents of this book covers the material required in the Fluid Mechanics Graduate Core Course (MEEN-621) and in Advanced Fluid Mechanics, a Ph.D-level elective course (MEEN-622), both of which I have been teaching at Texas A and M University for the past two decades. While there are numerous undergraduate fluid mechanics texts on the market for engineering students and instructors to choose from, there are only limited texts that comprehensively address the particular needs of graduate engineering fluid mechanics courses. To complement the lecture materials, the instructors more often recommend several texts, each of which treats special topics of fluid mechanics. This circumstance and the need to have a textbook that covers the materials needed in the above courses gave the impetus to provide the graduate engineering community with a coherent textbook that comprehensively addresses their needs for an advanced fluid mechanics text. Although this text book is primarily aimed at mechanical engineering students, it is equally suitable for aerospace engineering, civil engineering, other engineering disciplines, and especially those practicing professionals who perform CFD-simulation on a routine basis and would like to know more about the underlying physics of the commercial codes they use. Furthermore, it is suitable for self study, provided that the reader has a sufficient knowledge of calculus and differential equations. (orig.)

  15. The characteristics of mechanical engineering systems

    CERN Document Server

    Holmes, R

    1977-01-01

    The Characteristics of Mechanical Engineering Systems focuses on the characteristics that must be considered when designing a mechanical engineering system. Mechanical systems are presented on the basis of component input-output relationships, paying particular attention to lumped-parameter problems and the interrelationships between lumped components or """"black-boxes"""" in an engineering system. Electric motors and generators are treated in an elementary manner, and the principles involved are explained as far as possible from physical and qualitative reasoning. This book is comprised of

  16. Routine Design for Mechanical Engineering

    OpenAIRE

    Brinkop, Axel; Laudwein, Norbert; Maasen, Rudiger

    1995-01-01

    COMIX (configuration of mixing machines) is a system that assists members of the EKATO Sales Department in designing a mixing machine that fulfills the requirements of a customer. It is used to help the engineer design the requested machine and prepare an offer that's to be submitted to the customer. comix integrates more traditional software techniques with explicit knowledge representation and constraint propagation. During the process of routine design, some design decisions have to be mad...

  17. Boston Architectural College Urban Sustainability Initiative

    Energy Technology Data Exchange (ETDEWEB)

    Byers, Arthur C.

    2013-07-31

    runoff into the Charles River Basin in one of its most significantly polluted sections and, will provide a green renovation mechanism for the redirected storm water of a public alley way. This activity is designed to improve the quality of water recharging the ground water and protecting the vulnerable wood pilings under many of the historic masonry buildings in Boston's Back Bay. Sustainable design research and system monitoring opportunities will also be incorporated, providing ongoing tools for public outreach and education through innovative signage and "virtual tour" technology. The monitoring will include a "building performance dash board" that reflects real time operating conditions and improvements in environmental and economic performance to be prominently displayed on the face of our 320 Newbury Street building (approximately 1.5 million people walk by annually). The project site and demonstration area is located at the rear of 951 Boylston Street, Boston, MA 02115 and the parking area adjacent to Public Alley #444 in Boston's historic Back Bay. Task II of the project is Geothermal Solution. This task involves the installation of approximately seven Geothermal wells which will tap into the earth's constant underground temperatures to provide air-conditioning and heating for BAC facilities. The environmentally friendly geothermal system uses no fossil fuel, produces no emissions and runs silently, providing a sustainable model for commercial and residential buildings throughout Boston. Ultimately the combination of this project and other projects will assist in making the BAC "carbon-neutral", and could generate enough additional energy to provide free power to the Engine 33 and Ladder 15 Firehouse located at 941 Boylston Street. The project is located at the rear of 951 Boylston Street, Boston, MA 02115 and the parking area adjacent to Public Alley #444 in Boston's historic Back Bay. Task III of the project is the Sustainability Design

  18. Engineering Change Management Method Framework in Mechanical Engineering

    Science.gov (United States)

    Stekolschik, Alexander

    2016-11-01

    Engineering changes make an impact on different process chains in and outside the company, and lead to most error costs and time shifts. In fact, 30 to 50 per cent of development costs result from technical changes. Controlling engineering change processes can help us to avoid errors and risks, and contribute to cost optimization and a shorter time to market. This paper presents a method framework for controlling engineering changes at mechanical engineering companies. The developed classification of engineering changes and accordingly process requirements build the basis for the method framework. The developed method framework comprises two main areas: special data objects managed in different engineering IT tools and process framework. Objects from both areas are building blocks that can be selected to the overall business process based on the engineering process type and change classification. The process framework contains steps for the creation of change objects (both for overall change and for parts), change implementation, and release. Companies can select singleprocess building blocks from the framework, depending on the product development process and change impact. The developed change framework has been implemented at a division (10,000 employees) of a big German mechanical engineering company.

  19. Mechanical engineers' handbook, energy and power

    CERN Document Server

    Kutz, Myer

    2015-01-01

    The engineer's ready reference for mechanical power and heat Mechanical Engineer's Handbook provides the mostcomprehensive coverage of the entire discipline, with a focus onexplanation and analysis. Packaged as a modular approach, thesebooks are designed to be used either individually or as a set,providing engineers with a thorough, detailed, ready reference ontopics that may fall outside their scope of expertise. Each bookprovides discussion and examples as opposed to straight data andcalculations, giving readers the immediate background they needwhile pointing them toward more in-depth infor

  20. Mechanical engineering aspects of TFTR

    International Nuclear Information System (INIS)

    Citrolo, J.C.

    1983-04-01

    This paper briefly presents the principles which characterize a tokamak and discusses the mechanical aspects of TFTR, particularly the toroidal field coils and the vacuum chamber, in the context of being key components common to all tokamaks. The mechanical loads on these items as well as other design requirements are considered and the solutions to these requirements as executed in TFTR are presented. Future technological developments beyond the scope of TFTR, which are necessary to bring the tokamak concept to a full fusion-power system, are also presented. Additional methods of plasma heating, current drive, and first wall designs are examples of items in this category

  1. Optimization of a relativistic quantum mechanical engine.

    Science.gov (United States)

    Peña, Francisco J; Ferré, Michel; Orellana, P A; Rojas, René G; Vargas, P

    2016-08-01

    We present an optimal analysis for a quantum mechanical engine working between two energy baths within the framework of relativistic quantum mechanics, adopting a first-order correction. This quantum mechanical engine, with the direct energy leakage between the energy baths, consists of two adiabatic and two isoenergetic processes and uses a three-level system of two noninteracting fermions as its working substance. Assuming that the potential wall moves at a finite speed, we derive the expression of power output and, in particular, reproduce the expression for the efficiency at maximum power.

  2. Mechanical technology for higher engineering technicians

    CERN Document Server

    Black, Peter

    1972-01-01

    Mechanical Technology for Higher Engineering Technicians deals with the mechanics of machines, thermodynamics, and mechanics of fluids. This book presents discussions and examples that deal with the strength of materials, technology of machines, and techniques used by professional engineers. The book explains the strain energy of torsion, coil springs, and the effects of axial load. The author also discusses the forces that produce bending, shearing, and bending combined with direct stress, as well as beams subjected to a uniform bending moment or simply supported beams with concentrated non-c

  3. Computational structural mechanics for engine structures

    Science.gov (United States)

    Chamis, C. C.

    1989-01-01

    The computational structural mechanics (CSM) program at Lewis encompasses: (1) fundamental aspects for formulating and solving structural mechanics problems, and (2) development of integrated software systems to computationally simulate the performance/durability/life of engine structures. It is structured to mainly supplement, complement, and whenever possible replace, costly experimental efforts which are unavoidable during engineering research and development programs. Specific objectives include: investigate unique advantages of parallel and multiprocesses for: reformulating/solving structural mechanics and formulating/solving multidisciplinary mechanics and develop integrated structural system computational simulators for: predicting structural performances, evaluating newly developed methods, and for identifying and prioritizing improved/missing methods needed. Herein the CSM program is summarized with emphasis on the Engine Structures Computational Simulator (ESCS). Typical results obtained using ESCS are described to illustrate its versatility.

  4. Mechanical engineers' handbook, manufacturing and management

    CERN Document Server

    Kutz, Myer

    2015-01-01

    Full coverage of manufacturing and management in mechanicalengineering Mechanical Engineers' Handbook, Fourth Edition provides aquick guide to specialized areas that engineers may encounter intheir work, providing access to the basics of each and pointingtoward trusted resources for further reading, if needed. The book'saccessible information offers discussions, examples, and analysesof the topics covered, rather than the straight data, formulas, andcalculations found in other handbooks. No single engineer can be aspecialist in all areas that they are called upon to work in. It'sa discipline

  5. Micro electromechanical systems (MEMS) for mechanical engineers

    Energy Technology Data Exchange (ETDEWEB)

    Lee, A. P., LLNL

    1996-11-18

    The ongoing advances in Microelectromechanical Systems (MEMS) are providing man-kind the freedom to travel to dimensional spaces never before conceivable. Advances include new fabrication processes, new materials, tailored modeling tools, new fabrication machines, systems integration, and more detailed studies of physics and surface chemistry as applied to the micro scale. In the ten years since its inauguration, MEMS technology is penetrating industries of automobile, healthcare, biotechnology, sports/entertainment, measurement systems, data storage, photonics/optics, computer, aerospace, precision instruments/robotics, and environment monitoring. It is projected that by the turn of the century, MEMS will impact every individual in the industrial world, totaling sales up to $14 billion (source: System Planning Corp.). MEMS programs in major universities have spawned up all over the United States, preparing the brain-power and expertise for the next wave of MEMS breakthroughs. It should be pointed out that although MEMS has been initiated by electrical engineering researchers through the involvement of IC fabrication techniques, today it has evolved such that it requires a totally multi-disciplinary team to develop useful devices. Mechanical engineers are especially crucial to the success of MEMS development, since 90% of the physical realm involved is mechanical. Mechanical engineers are needed for the design of MEMS, the analysis of the mechanical system, the design of testing apparatus, the implementation of analytical tools, and the packaging process. Every single aspect of mechanical engineering is being utilized in the MEMS field today, however, the impact could be more substantial if more mechanical engineers are involved in the systems level designing. In this paper, an attempt is made to create the pathways for a mechanical engineer to enter in the MEMS field. Examples of application in optics and medical devices will be used to illustrate how mechanical

  6. International Conference on Mechanical Engineering and Technology

    CERN Document Server

    Mechanical Engineering and Technology

    2012-01-01

    The volume includes a set of selected papers extended and revised from the 2011 International Conference on Mechanical Engineering and Technology, held on London, UK, November 24-25, 2011.   Mechanical engineering technology is the application of physical principles and current technological developments to the creation of useful machinery and operation design. Technologies such as solid models may be used as the basis for finite element analysis (FEA) and / or computational fluid dynamics (CFD) of the design. Through the application of computer-aided manufacturing (CAM), the models may also be used directly by software to create "instructions" for the manufacture of objects represented by the models, through computer numerically controlled (CNC) machining or other automated processes, without the need for intermediate drawings.   This volume covers the subject areas of mechanical engineering and technology, and also covers interdisciplinary subject areas of computers, communications, control and automation...

  7. Mechanics of materials formulas and problems : engineering mechanics 2

    CERN Document Server

    Gross, Dietmar; Wriggers, Peter; Schröder, Jörg; Müller, Ralf

    2017-01-01

    This book contains the most important formulas and more than 140 completely solved problems from Mechanics of Materials and Hydrostatics. It provides engineering students material to improve their skills and helps to gain experience in solving engineering problems. Particular emphasis is placed on finding the solution path and formulating the basic equations. Topics include: - Stress - Strain - Hooke’s Law - Tension and Compression in Bars - Bending of Beams - Torsion - Energy Methods - Buckling of Bars - Hydrostatics .

  8. Mechanics, Models and Methods in Civil Engineering

    CERN Document Server

    Maceri, Franco

    2012-01-01

    Mechanics, Models and Methods in Civil Engineering” collects leading papers dealing with actual Civil Engineering problems. The approach is in the line of the Italian-French school and therefore deeply couples mechanics and mathematics creating new predictive theories, enhancing clarity in understanding, and improving effectiveness in applications. The authors of the contributions collected here belong to the Lagrange Laboratory, an European Research Network active since many years. This book will be of a major interest for the reader aware of modern Civil Engineering.

  9. Elements of theoretical mechanics for electronic engineers

    CERN Document Server

    Bultot, Franz

    1965-01-01

    Elements of Theoretical Mechanics for Electronic Engineers deals with theoretical mechanics, which is considered one of the fundamental branches of instruction essential to training an engineer. This book discusses the oscillatory motions and their counterparts in electrical circuits and radio, and provides an introduction to differential operators of vector field theory. Other topics covered include systems and functions of vectors; dynamics of a free point; vibrations and waves; and statics. Worked examples and many notes on the application of most sections of the theories to electrical deve

  10. 46 CFR 12.15-13 - Deck engine mechanic.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Deck engine mechanic. 12.15-13 Section 12.15-13 Shipping... ENDORSEMENTS Qualified Member of the Engine Department § 12.15-13 Deck engine mechanic. (a) An applicant for an endorsement as deck engine mechanic shall be a person holding an MMC or MMD endorsed as junior engineer. The...

  11. Mechanical Engineering Department engineering research: Annual report, FY 1986

    International Nuclear Information System (INIS)

    Denney, R.M.; Essary, K.L.; Genin, M.S.; Highstone, H.H.; Hymer, J.D.; Taft, S.O.

    1986-12-01

    This report provides information on the five areas of research interest in LLNL's Mechanical Engineering Department. In Computer Code Development, a solid geometric modeling program is described. In Dynamic Systems and Control, structure control and structure dynamics are discussed. Fabrication technology involves machine cutting, interferometry, and automated optical component manufacturing. Materials engineering reports on composite material research and measurement of molten metal surface properties. In Nondestructive Evaluation, NMR, CAT, and ultrasound machines are applied to manufacturing processes. A model for underground collapse is developed. Finally, an alternative heat exchanger is investigated for use in a fusion power plant. Separate abstracts were prepared for each of the 13 reports in this publication

  12. Thermal integrity in mechanics and engineering

    CERN Document Server

    Shorr, Boris F

    2015-01-01

    The book is targeted at engineers, university lecturers, postgraduates, and final year undergraduate students involved in computational modelling and experimental and theoretical analysis of the high-temperature behavior of engineering structures. It will also be of interest to researchers developing the thermal strength theory as a branch of continuum mechanics. Thermal integrity is a multidisciplinary field combining the expertise of mechanical engineers, material scientists and applied mathematicians, each approaching the problem from their specific viewpoint. This monograph draws on the research of a broad scientific community including the author’s contribution. The scope of thermal strength analysis was considerably extended thanks to modern computers and the implementation of FEM codes. However, the author believes that some material models adopted in the advanced high-performance software, are not sufficiently justificated due to lack of easy-to-follow books on the theoretical and experimental aspec...

  13. Gasoline Engine Mechanics. Performance Objectives. Intermediate Course.

    Science.gov (United States)

    Jones, Marion

    Several intermediate performance objectives and corresponding criterion measures are listed for each of six terminal objectives presented in this curriculum guide for an intermediate gasoline engine mechanics course at the secondary level. (For the beginning course guide see CE 010 947.) The materials were developed for a two-semester (2 hour…

  14. Quantum mechanics for applied physics and engineering

    CERN Document Server

    Fromhold, Albert T

    2011-01-01

    This excellent text, directed to upper-level undergraduates and graduate students in engineering and applied physics, introduces the fundamentals of quantum mechanics, emphasizing those aspects of quantum mechanics and quantum statistics essential to an understanding of solid-state theory. A heavy background in mathematics and physics is not required beyond basic courses in calculus, differential equations, and calculus-based elementary physics.The first three chapters introduce quantum mechanics (using the Schrödinger equations), quantum statistics, and the free-electron theory of metals. Ch

  15. DESIGN QUALITY IN MECHANICAL ENGINEERING APPLICATION

    Directory of Open Access Journals (Sweden)

    Ayşegül Akdogan Eker

    2010-09-01

    Full Text Available There is a close relationship between material chose and quality in mechanical engineering application like there is in all the other engineering applications. If this relation is balanced then engineering success increases. Material chose comes to fore in the design process most of the time. The two most important responsibilities of the design engineer in here is to chose suitable material and to know the production processes about design. The chose of material of a design that will fulfill the needs all through its life has great importance. It is needed to limit the material applicants by choosing the most suitable ones among variable material. Choosing materials that were examined before and whose behavior is well known provides the designer to feel confident. However since using highly successful materials would increase the competitive power of the designs; designers should follow the developments in materials and know the features of new materials. The description of these features can be interpreted within quality. Quality from the point of engineer is the total fulfillment of expectations.Engineer today are faced with very important problems such as fast technological innovations, a dynamic socio-economical environment, global rivalry. One of the life buoys they stick while trying to solve these problems is total method of quality control. Total Quality model which can provide higher competitive power compared to classical management model brings success only when applied with its whole components. "Approach toward prevention" and "measurement and statistics" have an important place among these elements. The first step of the approach toward prevention composes of design quality and Quality Function Deployment (QFD, or in other words The House of Quality method that will provide this. In this paper; considering the quality function deployment, how the chose of material are done in mechanical engineering applications will be explained.

  16. Mathematical formulas for industrial and mechanical engineering

    CERN Document Server

    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

  17. Mechanical Engineering Department engineering research: Annual report, FY 1986

    Energy Technology Data Exchange (ETDEWEB)

    Denney, R.M.; Essary, K.L.; Genin, M.S.; Highstone, H.H.; Hymer, J.D.; Taft, S.O. (eds.)

    1986-12-01

    This report provides information on the five areas of research interest in LLNL's Mechanical Engineering Department. In Computer Code Development, a solid geometric modeling program is described. In Dynamic Systems and Control, structure control and structure dynamics are discussed. Fabrication technology involves machine cutting, interferometry, and automated optical component manufacturing. Materials engineering reports on composite material research and measurement of molten metal surface properties. In Nondestructive Evaluation, NMR, CAT, and ultrasound machines are applied to manufacturing processes. A model for underground collapse is developed. Finally, an alternative heat exchanger is investigated for use in a fusion power plant. Separate abstracts were prepared for each of the 13 reports in this publication. (JDH)

  18. A new guide of mechanical engineering

    International Nuclear Information System (INIS)

    1993-01-01

    This book introduces a new guide of mechanical engineering which deals with basic thing such as mathematical formula, dynamics, material dynamics, industrial materials, machine design like screws and rivets, gears and springs, the method of machine such as drilling machine and its work, planar, shaper and slotter and their work, honing and super finishing machine and their work, measuring of machine, test and machine, hydraulics and hydraulic machine and telecommunication equipment and automation.

  19. Thermal integrity in mechanics and engineering

    International Nuclear Information System (INIS)

    Shorr, Boris F.

    2015-01-01

    The book is targeted at engineers, university lecturers, postgraduates, and final year undergraduate students involved in computational modelling and experimental and theoretical analysis of the high-temperature behavior of engineering structures. It will also be of interest to researchers developing the thermal strength theory as a branch of continuum mechanics. Thermal integrity is a multidisciplinary field combining the expertise of mechanical engineers, material scientists and applied mathematicians, each approaching the problem from their specific viewpoint. This monograph draws on the research of a broad scientific community including the author's contribution. The scope of thermal strength analysis was considerably extended thanks to modern computers and the implementation of FEM codes. However, the author believes that some material models adopted in the advanced high-performance software, are not sufficiently justificated due to lack of easy-to-follow books on the theoretical and experimental aspects of thermal integrity. The author endeavors to provide a thorough yet sufficiently simple presentation of the underlying concepts, making the book compelling to a wide audience.

  20. Thermal integrity in mechanics and engineering

    Energy Technology Data Exchange (ETDEWEB)

    Shorr, Boris F. [Central Institute of Aviation Motors (CIAM), Moscow (Russian Federation)

    2015-07-01

    The book is targeted at engineers, university lecturers, postgraduates, and final year undergraduate students involved in computational modelling and experimental and theoretical analysis of the high-temperature behavior of engineering structures. It will also be of interest to researchers developing the thermal strength theory as a branch of continuum mechanics. Thermal integrity is a multidisciplinary field combining the expertise of mechanical engineers, material scientists and applied mathematicians, each approaching the problem from their specific viewpoint. This monograph draws on the research of a broad scientific community including the author's contribution. The scope of thermal strength analysis was considerably extended thanks to modern computers and the implementation of FEM codes. However, the author believes that some material models adopted in the advanced high-performance software, are not sufficiently justificated due to lack of easy-to-follow books on the theoretical and experimental aspects of thermal integrity. The author endeavors to provide a thorough yet sufficiently simple presentation of the underlying concepts, making the book compelling to a wide audience.

  1. Research Skills Enhancement in Future Mechanical Engineers

    Directory of Open Access Journals (Sweden)

    Jorge Lino Alves

    2011-04-01

    Full Text Available Nowadays, the Web is a common tool for students searching information about the subjects taught in the different university courses. Although this is a good tool for the first rapid knowledge, a deeper study is usually demanded.

    After many years of teaching a course about ceramic and composite materials in the Integrated Master in Mechanical Engineering of Faculty of Engineering of University of Porto, Portugal, the authors used the Bologna reformulation of the mechanical engineering course to introduce new teaching methodologies based on a project based learning methodology.

    One of the main innovations is a practical work that comprises the study of a recent ceramic scientific paper, using all the actual available tools, elaboration of a scientific report, work presentation and participation in a debate.

    With this innovative teaching method the enrolment of the students was enhanced with a better knowledge about the ceramics subject and the skills related with the CDIO competences.

    This paper presents the reasons for this implementation and explains the teaching methodology adopted as well as the changes obtained in the students’ final results.

  2. Propulsion Mechanism of Catalytic Microjet Engines.

    Science.gov (United States)

    Fomin, Vladimir M; Hippler, Markus; Magdanz, Veronika; Soler, Lluís; Sanchez, Samuel; Schmidt, Oliver G

    2014-02-01

    We describe the propulsion mechanism of the catalytic microjet engines that are fabricated using rolled-up nanotech. Microjets have recently shown numerous potential applications in nanorobotics but currently there is a lack of an accurate theoretical model that describes the origin of the motion as well as the mechanism of self-propulsion. The geometric asymmetry of a tubular microjet leads to the development of a capillary force, which tends to propel a bubble toward the larger opening of the tube. Because of this motion in an asymmetric tube, there emerges a momentum transfer to the fluid. In order to compensate this momentum transfer, a jet force acting on the tube occurs. This force, which is counterbalanced by the linear drag force, enables tube velocities of the order of 100 μ m/s. This mechanism provides a fundamental explanation for the development of driving forces that are acting on bubbles in tubular microjets.

  3. Essays on the history of mechanical engineering

    CERN Document Server

    Genchi, Giuseppe

    2016-01-01

    This book treats several subjects from the History of Mechanism and Machine Science, and also contains an illustrative presentation of the Museum of Engines and Mechanisms of the University of Palermo, Italy, which houses a collection of various pieces of machinery from the last 150 years. The various sections deal with some eminent scientists of the past, with the history of industrial installations, machinery and transport, with the human inventiveness for mechanical and scientific devices, and with robots and human-driven automata. All chapters have been written by experts in their fields. The volume shows a wide-ranging panorama on the historical progress of scientific and technical knowledge in the past centuries. It will stimulate new research and ideas for those involved in the history of Science and Technology.

  4. Superconducting Qubits as Mechanical Quantum Engines.

    Science.gov (United States)

    Sachtleben, Kewin; Mazon, Kahio T; Rego, Luis G C

    2017-09-01

    We propose the equivalence of superconducting qubits with a pistonlike mechanical quantum engine. The work reports a study on the nature of the nonequilibrium work exchanged with the quantum-nonadiabatic working medium, which is modeled as a multilevel coupled quantum well system subject to an external control parameter. The quantum dynamics is solved for arbitrary control protocols. It is shown that the work output has two components: one that depends instantaneously on the level populations and another that is due to the quantum coherences built in the system. The nonadiabatic coherent dynamics of the quantum engine gives rise to a resistance (friction) force that decreases the work output. We consider the functional equivalence of such a device and a rf-SQUID flux qubit.

  5. Simulation based engineering in solid mechanics

    CERN Document Server

    Rao, J S

    2017-01-01

    This book begins with a brief historical perspective of the advent of rotating machinery in 20th century Solid Mechanics and the development of the discipline of the Strength of Materials. High Performance Computing (HPC) and Simulation Based Engineering Science (SBES) have gradually replaced the conventional approach in Design bringing science directly into engineering without approximations. A recap of the required mathematical principles is given. The science of deformation, strain and stress at a point under the application of external traction loads is next presented. Only one-dimensional structures classified as Bars (axial loads), Rods (twisting loads) and Beams (bending loads) are considered in this book. The principal stresses and strains and von Mises stress and strain that used in design of structures are next presented. Lagrangian solution was used to derive the governing differential equations consistent with assumed deformation field and solution for deformations, strains and stresses were obtai...

  6. Mechanics of materials an introduction to engineering technology

    CERN Document Server

    Ghavami, Parviz

    2015-01-01

    This book, framed in the processes of engineering analysis and design, presents concepts in mechanics of materials for students in two-year or four-year programs in engineering technology, architecture, and building construction, as well as for students in vocational schools and technical institutes. Using the principles and laws of mechanics, physics, and the fundamentals of engineering, Mechanics of Materials: An Introduction for Engineering Technology will help aspiring and practicing engineers and engineering technicians from across disciplines—mechanical, civil, chemical, and electrical—apply concepts of engineering mechanics for analysis and design of materials, structures, and machine components. The book is ideal for those seeking a rigorous, algebra/trigonometry-based text on the mechanics of materials. This book also: ·       Elucidates concepts of engineering mechanics in materials, including stress and strain, force systems on structures, moment of inertia, and shear and bending moments...

  7. Stirling engine control mechanism and method

    Science.gov (United States)

    Dineen, John J.

    1983-01-01

    A reciprocating-to-rotating motion conversion and power control device for a Stirling engine includes a hub mounted on an offset portion of the output shaft for rotation relative to the shaft and for sliding motion therealong which causes the hub to tilt relative to the axis of rotation of the shaft. This changes the angle of inclination of the hub relative to the shaft axis and changes the axial stroke of a set of arms connected to the hub and nutating therewith. A hydraulic actuating mechanism is connected to the hub for moving its axial position along the shaft. A balancing wheel is linked to the hub and changes its angle of inclination as the angle of inclination of the hub changes to maintain the mechanism in perfect balance throughout its range of motion.

  8. Reflections on Jonathan Boston's Paper

    Science.gov (United States)

    Devine, Nesta

    2014-01-01

    In this article, Nesta Devine responds to Jonathan Boston's article "Child Poverty in New Zealand: Why It Matters and How It Can Be Reduced" ("Educational Philosophy and Theory," v46 n9 p995-999, 2014). Devine wishes to consider Boston's position from two angles: one is to rehearse the point that these statistics are an…

  9. Geometry of surfaces a practical guide for mechanical engineers

    CERN Document Server

    Radzevich, Stephen P

    2012-01-01

    Presents an in-depth analysis of geometry of part surfaces and provides the tools for solving complex engineering problems Geometry of Surfaces: A Practical Guide for Mechanical Engineers is a comprehensive guide to applied geometry of surfaces with focus on practical applications in various areas of mechanical engineering. The book is divided into three parts on Part Surfaces, Geometry of Contact of Part Surfaces and Mapping of the Contacting Part Surfaces. Geometry of Surfaces: A Practical Guide for Mechanical Engineers combines differential geometry and gearing theory and presents new developments in the elementary theory of enveloping surfaces. Written by a leading expert of the field, this book also provides the reader with the tools for solving complex engineering problems in the field of mechanical engineering. Presents an in-depth analysis of geometry of part surfaces Provides tools for solving complex engineering problems in the field of mechanical engineering Combines differential geometry an...

  10. Engineering of Impulse Mechanism for Mechanical Hander Power Tools

    Science.gov (United States)

    Nikolaevich Drozdov, Anatoliy

    2018-03-01

    The solution to the problem of human security in cities should be considered on the basis of an integrated and multidisciplinary approach, including issues of security and ecology in the application of technical means used to ensure the viability and development of technocracy. In this regard, an important task is the creation of a safe technique with improved environmental properties with high technological characteristics. This primarily relates to mechanised tool — the division of technological machines with built in engines is that their weight is fully or partially perceived by the operator’s hands, making the flow and control of the car. For this subclass of machines is characterized by certain features: a built-in motor, perception of at least part of their weight by the operator during the work, the implementation of feeding and management at the expense of the muscular power of the operator. Therefore, among the commonly accepted technical and economic characteristics, machines in this case, important ergonomic (ergonomics), regulation of levels which ensures the safety of the operator. To ergonomics include vibration, noise characteristics, mass, and force feeding machine operator. Vibration is a consequence of the dynamism of the system operator machine - processed object (environment) in which the engine energy is redistributed among all the structures, causing their instability. In the machine vibration caused by technological and constructive (transformative mechanisms) unbalance of individual parts of the drive, the presence of technological and design (impact mechanisms) clearances and other reasons. This article describes a new design of impulse mechanism for hander power tools (wrenches, screwdrivers) with enhanced torque. The article substantiates a simulation model of dynamic compression process in an operating chamber during impact, provides simulation results and outlines further lines of research.

  11. Mechanical Engineering Senior Design Project Final Presentations | College

    Science.gov (United States)

    Engineering Research Computational Mechanics Laboratory Environmental Engineering Laboratory Geotechnical of Engineering & Applied Science A B C D E F G H I J K L M N O P Q R S T U V W X Y Z D2L Programs Concentration in Biomedical Engineering Concentration on Ergonomics M.S. Program in Computer

  12. DESIGN OPTIMIZATION METHOD USED IN MECHANICAL ENGINEERING

    Directory of Open Access Journals (Sweden)

    SCURTU Iacob Liviu

    2016-11-01

    Full Text Available This paper presents an optimization study in mechanical engineering. First part of the research describe the structural optimization method used, followed by the presentation of several optimization studies conducted in recent years. The second part of the paper presents the CAD modelling of an agricultural plough component. The beam of the plough is analysed using finite element method. The plough component is meshed in solid elements, and the load case which mimics the working conditions of agricultural equipment of this are created. The model is prepared to find the optimal structural design, after the FEA study of the model is done. The mass reduction of part is the criterion applied for this optimization study. The end of this research presents the final results and the model optimized shape.

  13. The Clean Development Mechanism Re-engineered

    DEFF Research Database (Denmark)

    Lütken, Søren

    2016-01-01

    for engineering such mechanism, or indeed reengineering the CDM itself, to make it a viable mitigation financing tool, providing receipts for payments in the form of certified emission reductions (CER). Two solutions are presented, both of which secure new financing for projects that deliver real and measurable...... emissions reduction benefits on the basis of prospective revenues from emissions reduction: one introduces up-front securitization of the emissions reductions; the other builds on a defined value of the CERs without the need for a carbon price or a market for trading. Most of us use simple heuristics...... time. Simply put CERs are not project finance and do not address project capital needs when most needed — upfront. CER based returns are available only after a project is operational. That is why only one third of registered CDM projects went as far as to get their carefully calculated CERs issued...

  14. Application of Modern Simulation Technology in Mechanical Outstanding Engineer Training

    Directory of Open Access Journals (Sweden)

    Gongfa Li

    2014-03-01

    Full Text Available This text has described the relationship between outstanding engineer training and modern simulation technology, have recommended the characteristics of mechanical outstanding engineer in detail. Aiming at the importance of the teaching practice link to course of theory of mechanics, mechanical design and mechanical signal analysis, have expounded the function of modern simulation technology in the mechanical outstanding engineer training, especially on teaching practice in the theory of mechanics, mechanical design and mechanical signal analysis. It has the advantages of economizing the teaching cost, overcoming the hardware constrains, model prediction, promoting student's innovation and manipulative ability, so can popularize and develop in a more cost-effective manner in the university.

  15. International Conference on Research and Innovations in Mechanical Engineering

    CERN Document Server

    Singh, Paramjit; Singh, Harwinder; Brar, Gurinder

    2014-01-01

    This book comprises the proceedings of International Conference on Research and Innovations in Mechanical Engineering (ICRIME 2013) organized by Guru Nanak Dev Engineering College, Ludhiana with support from AICTE, TEQIP, DST and PTU, Jalandhar. This international conference served as a premier forum for communication of new advances and research results in the fields of mechanical engineering. The proceedings reflect the conference’s emphasis on strong methodological approaches and focus on applications within the domain of mechanical engineering. The contents of this volume aim to highlight new theoretical and experimental findings in the fields of mechanical engineering and closely related fields, including interdisciplinary fields such as robotics and mechatronics.

  16. Condition and prospects of development of agricultural mechanical engineering

    OpenAIRE

    Vsevolod Babushkin; Margarita Ignatyeva

    2011-01-01

    In this paper, an estimation of condition and level of development of agricultural mechanical engineering is given; also an expert estimation of scales of the Russian market of agricultural machinery is given. The factors negatively influencing formation of the named market are designated. Features and prospects of development of agricultural mechanical engineering of Sverdlovsk region are defined. State regulation mechanisms of domestic agricultural mechanical engineering development are des...

  17. 2dF mechanical engineering

    Science.gov (United States)

    Smith, Greg; Lankshear, Allan

    1998-07-01

    2dF is a multi-object instrument mounted at prime focus at the AAT capable of spectroscopic analysis of 400 objects in a single 2 degree field. It also prepares a second 2 degree 400 object field while the first field is being observed. At its heart is a high precision robotic positioner that places individual fiber end magnetic buttons on one of two field plates. The button gripper is carried on orthogonal gantries powered by linear synchronous motors and contains a TV camera which precisely locates backlit buttons to allow placement in user defined locations to 10 (mu) accuracy. Fiducial points on both plates can also be observed by the camera to allow repeated checks on positioning accuracy. Field plates rotate to follow apparent sky rotation. The spectrographs both analyze light from the 200 observing fibers each and back- illuminate the 400 fibers being re-positioned during the observing run. The 2dF fiber position and spectrograph system is a large and complex instrument located at the prime focus of the Anglo Australian Telescope. The mechanical design has departed somewhat from the earlier concepts of Gray et al, but still reflects the audacity of those first ideas. The positioner is capable of positioning 400 fibers on a field plate while another 400 fibers on another plate are observing at the focus of the telescope and feeding the twin spectrographs. When first proposed it must have seemed like ingenuity unfettered by caution. Yet now it works, and works wonderfully well. 2dF is a system which functions as the result of the combined and coordinated efforts of the astronomers, the mechanical designers and tradespeople, the electronic designers, the programmers, the support staff at the telescope, and the manufacturing subcontractors. The mechanical design of the 2dF positioner and spectrographs was carried out by the mechanical engineering staff of the AAO and the majority of the manufacture was carried out in the AAO workshops.

  18. Biology: An Important Agricultural Engineering Mechanism

    Science.gov (United States)

    Henderson, S. M.

    1974-01-01

    Describes the field of bioengineering with particular emphasis on agricultural engineering, and presents the results of a survey of schools that combine biology and engineering in their curricula. (JR)

  19. Mechanical Engineering Practice – using a simple Stirling engine as case

    DEFF Research Database (Denmark)

    Meyer, Knud Erik

    2011-01-01

    The first technical course that students in mechanical engineering take at the Technical University of Denmark is called “Mechanical Engineering Practice”. We have used a simple Stirling engine as a design-implement project. Students were asked to design and build a heat engine using materials....... The Stirling engine worked well in the drawing assignments. The Stirling engine also served as illustration of coming courses in mechanical engineering. The resulting engines had large variations in their design and most groups succeeded in building a functioning engine. However, achieved efficiencies were...... obtained by their own means and were competing on achieving the highest efficiency. We added an extra dimension to the project by making detailed measurements of the pressure variation to check simple thermodynamic models of the engine. The course had integrated lessons in sketching and technical drawing...

  20. 76 FR 37005 - Safety Zone; Fan Pier Yacht Club Fireworks, Boston Harbor, Boston, MA

    Science.gov (United States)

    2011-06-24

    ...-AA00 Safety Zone; Fan Pier Yacht Club Fireworks, Boston Harbor, Boston, MA AGENCY: Coast Guard, DHS... Sector Boston Captain of the Port (COTP) Zone for the Fan Pier Yacht Club Fireworks display. This safety... Safety Zone; Fan Pier Yacht Club Fireworks, Boston Harbor, Boston, Massachusetts. (a) General. A...

  1. Use of fracture mechanics in engineering problems

    Energy Technology Data Exchange (ETDEWEB)

    Carter, C S

    1965-02-26

    If an engineering material containing a crack is subjected to a slowly increasing load, applied so that the crack tends to open, a small zone of plastic yielding develops at the crack tip. This zone increases in size with increasing load, and has the effect of resisting the tendency of the crack to extend. The basic concepts of fracture mechanics are outlined and the significance of crack toughness as measured by KDcU and KD1cU which relate the applied stress and crack size for unstable fracture prior to general yielding is discussed. The methods available for crack-toughness evaluation are indicated, and the mathematical expressions describing KDcU and KD1cU for a variety of geometrical situations are quoted. This approach to the design of fracture- resistant structures has been used in a number of fields in the U.S. and could be of value to the British steam turbine, aerospace, and pressure-vessel industries for design, inspection, and material selection. (64 refs.)

  2. IECEC '91; Proceedings of the 26th Intersociety Energy Conversion Engineering Conference, Boston, MA, Aug. 4-9, 1991. Vol 6

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    Papers are presented on aerospace power systems (burst and pulse power, simulation, solar dynamics, and space nuclear systems, etc.), conversion technologies, electrochemical conversion, and energy conservation. Consideration is also given to energy systems and alternative fuels, renewable resource systems, Stirling engines and applications, and innovative and advanced systems (e.g., superconducting power and magnetic devices at high temperature)

  3. Summary of Research 2001, Department of Mechanical Engineering, Graduate School of Engineering and Applied Sciences

    National Research Council Canada - National Science Library

    McNelley, Terry

    2002-01-01

    This report contains project summaries of the research projects in the Department of Mechanical Engineering A list of recent publications is also included, which consists of conference presentations...

  4. Statics formulas and problems : engineering mechanics 1

    CERN Document Server

    Gross, Dietmar; Wriggers, Peter; Schröder, Jörg; Müller, Ralf

    2017-01-01

    This book contains the most important formulas and more than 160 completely solved problems from Statics. It provides engineering students material to improve their skills and helps to gain experience in solving engineering problems. Particular emphasis is placed on finding the solution path and formulating the basic equations. Topics include: - Equilibrium - Center of Gravity, Center of Mass, Centroids - Support Reactions - Trusses - Beams, Frames, Arches - Cables - Work and Potential Energy - Static and Kinetic Friction - Moments of Inertia.

  5. A new and efficient mechanism for spark ignition engines

    International Nuclear Information System (INIS)

    Shadloo, M.S.; Poultangari, R.; Abdollahzadeh Jamalabadi, M.Y.; Rashidi, M.M.

    2015-01-01

    Highlights: • A new slider–crank mechanism, with superior performance is presented. • Thermodynamic processes as well as vibration and internal forces have been modeled. • Comparison with the conventional four-stroke spark ignition engines is made. • Advantages and disadvantages of the proposed mechanism are discussed. - Abstract: In this paper a new symmetrical crank and slider mechanism is proposed and a zero dimensional model is utilized to study its combustion performance enhancement in a four-stroke spark ignition (SI) engine. The main features of this new mechanism are superior thermodynamic efficiency, lower internal frictions, and lower pollutants. Comparison is made between its performance and that of the conventional four-stroke SI engines. Presented mechanism is designed to provide better fuel consumption of internal combustion engines. These advantages over standard engine are achieved through synthesis of new mechanism. Numerical calculation have been performed for several cases of different mechanism parameters, compression ratio and engine speed. A comprehensive comparison between their thermodynamic processes as well as vibration and internal forces has been done. Calculated efficiency and power diagrams are plotted and compared with performance of a conventional SI engine. Advantages and disadvantages of the proposed mechanism are discussed in details

  6. Mechanical and materials engineering of modern structure and component design

    CERN Document Server

    Altenbach, Holm

    2015-01-01

    This book presents the latest findings on mechanical and materials engineering as applied to the design of modern engineering materials and components. The contributions cover the classical fields of mechanical, civil and materials engineering, as well as bioengineering and advanced materials processing and optimization. The materials and structures discussed can be categorized into modern steels, aluminium and titanium alloys, polymers/composite materials, biological and natural materials, material hybrids and modern nano-based materials. Analytical modelling, numerical simulation, state-of-the-art design tools and advanced experimental techniques are applied to characterize the materials’ performance and to design and optimize structures in different fields of engineering applications.

  7. Dynamics formulas and problems : engineering mechanics 3

    CERN Document Server

    Gross, Dietmar; Wriggers, Peter; Schröder, Jörg; Müller, Ralf

    2017-01-01

    This book contains the most important formulas and more than 190 completely solved problems from Kinetics and Hydrodynamics. It provides engineering students material to improve their skills and helps to gain experience in solving engineering problems. Particular emphasis is placed on finding the solution path and formulating the basic equations. Topics include: - Kinematics of a Point - Kinetics of a Point Mass- Dynamics of a System of Point Masses - Kinematics of Rigid Bodies - Kinetics of Rigid Bodies - Impact - Vibrations - Non-Inertial Reference Frames - Hydrodynamics .

  8. Development of Engineering Design Education in the Department of Mechanical Engineering at Kanazawa Technical College

    Science.gov (United States)

    Yamada, Hirofumi; Ten-Nichi, Michio; Mathui, Hirosi; Nakamura, Akizi

    This paper introduces a method of the engineering design education for college of technology mechanical engineering students. In order to teach the practical engineering design, the MIL-STD-499A process is adapted and improved upon for a Mechatronics hands-on lesson used as the MOT method. The educational results in five years indicate that knowledge of the engineering management is useful for college students in learning engineering design. Portfolio for lessons and the hypothesis method also have better effects on the understanding of the engineering specialty.

  9. The role of mechanical loading in ligament tissue engineering.

    Science.gov (United States)

    Benhardt, Hugh A; Cosgriff-Hernandez, Elizabeth M

    2009-12-01

    Tissue-engineered ligaments have received growing interest as a promising alternative for ligament reconstruction when traditional transplants are unavailable or fail. Mechanical stimulation was recently identified as a critical component in engineering load-bearing tissues. It is well established that living tissue responds to altered loads through endogenous changes in cellular behavior, tissue organization, and bulk mechanical properties. Without the appropriate biomechanical cues, new tissue formation lacks the necessary collagenous organization and alignment for sufficient load-bearing capacity. Therefore, tissue engineers utilize mechanical conditioning to guide tissue remodeling and improve the performance of ligament grafts. This review provides a comparative analysis of the response of ligament and tendon fibroblasts to mechanical loading in current bioreactor studies. The differential effect of mechanical stimulation on cellular processes such as protease production, matrix protein synthesis, and cell proliferation is examined in the context of tissue engineering design.

  10. Mathematical Building-Blocks in Engineering Mechanics

    Science.gov (United States)

    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…

  11. Healthcare Technology Management (HTM) of mechanical ventilators by clinical engineers.

    Science.gov (United States)

    Yoshioka, Jun; Nakane, Masaki; Kawamae, Kaneyuki

    2014-01-01

    Mechanical ventilator failures expose patients to unacceptable risks, and maintaining mechanical ventilator safety is an important issue. We examined the usefulness of maintaining mechanical ventilators by clinical engineers (CEs) using a specialized calibrator. These evaluations and the ability to make in-house repairs proved useful for obviating the need to rent ventilators which, in turn, might prove faulty themselves. The CEs' involvement in maintaining mechanical ventilators is desirable, ensures prompt service, and, most importantly, enhances safe management of mechanical ventilators.

  12. The development and application of CFD technology in mechanical engineering

    Science.gov (United States)

    Wei, Yufeng

    2017-12-01

    Computational Fluid Dynamics (CFD) is an analysis of the physical phenomena involved in fluid flow and heat conduction by computer numerical calculation and graphical display. The numerical method simulates the complexity of the physical problem and the precision of the numerical solution, which is directly related to the hardware speed of the computer and the hardware such as memory. With the continuous improvement of computer performance and CFD technology, it has been widely applied to the field of water conservancy engineering, environmental engineering and industrial engineering. This paper summarizes the development process of CFD, the theoretical basis, the governing equations of fluid mechanics, and introduces the various methods of numerical calculation and the related development of CFD technology. Finally, CFD technology in the mechanical engineering related applications are summarized. It is hoped that this review will help researchers in the field of mechanical engineering.

  13. 2012 International Conference on Mechanical and Electronic Engineering

    CERN Document Server

    Lin, Sally; ICMEE2012; Advances in Mechanical and Electronic Engineering v.2

    2012-01-01

    This book includes the volume 2 of the proceedings of the 2012 International Conference on Mechanical and Electronic Engineering(ICMEE2012), held at June 23-24,2012 in Hefei, China. The conference provided a rare opportunity to bring together worldwide researchers who are working in the fields. This volume 2 is focusing on Mechatronic Engineering and Technology,  Electronic Engineering and Electronic Information Technology .

  14. Formula Student as Part of a Mechanical Engineering Curriculum

    Science.gov (United States)

    Davies, Huw Charles

    2013-01-01

    Formula Student (FS) is a multi-university student design competition managed by the UK Institution of Mechanical Engineers. Students are required to demonstrate and prove their creativity and engineering skills through the design, manufacture and financing of a small formula style race car. This paper seeks to explore the educational value that…

  15. Mechanical design and engineering calculation of the SMCAMS magnet

    International Nuclear Information System (INIS)

    Chen Guosheng

    2001-01-01

    The basis of the mechanical design of the SMCAMS magnet, and the structure characters of the magnet and its coils are introduced. Finally, the engineering design of other parts, including deflectors, probes and accelerating electrodes are described

  16. IECEC '91; Proceedings of the 26th Intersociety Energy Conversion Engineering Conference, Boston, MA, Aug. 4-9, 1991. Vol. 5 - Renewable resource systems, Stirling engines and applications, systems and cycles

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    Various papers on energy conversion engineering are presented. The general topics considered are: developments in nuclear power, energy from waste and biomass, system performance and materials in photovoltaics, solar thermal energy, wind energy systems, Stirling cycle analysis, Stirling cycle power, Stirling component technology, Stirling cooler/heat pump developments, Stirling engine concepts, Stirling engine design and optimization, Stirling engine dynamics and response, Stirling engine solar terrestrial, advanced cogeneration, AMTC, fossil fuel systems and technologies, marine energy

  17. Analysis of the Lifecycle of Mechanical Engineering Products

    OpenAIRE

    Gubaidulina, Rauza Khamidovna; Gruby, S. V.; Davlatov, G. D.

    2016-01-01

    Principal phases of the lifecycle of mechanical engineering products are analyzed in the paper. The authors have developed methods and procedures to improve designing, manufacturing, operating and recycling of the machine. It has been revealed that economic lifecycle of the product is a base for appropriate organization of mechanical engineering production. This lifecycle is calculated as a minimal sum total of consumer and producer costs. The machine construction and its manufacturing techno...

  18. Elements of Motivational Structure for Studying Mechanical Engineering

    OpenAIRE

    Nikša Dubreta; Damir Miloš

    2017-01-01

    The article presents the findings on students' reasons for studying mechanical engineering. These reasons were covered in terms of extrinsic and intrinsic motivation additionally related to selected independent variables of the sample – students' secondary school Grade Point Average, their gender and the socio-economic status. The research was conducted with the first year students of the Faculty of Mechanical Engineering at the University of Zagreb, Croatia. The sample consisted of 282 stude...

  19. Creating mechanisms of toxic substances emission of combustion engines

    OpenAIRE

    Jankowski Antoni; Kowalski Mirosław

    2015-01-01

    The paper analyses the mechanisms of creation of toxic exhaust gases, which mainly derived from inexact fuel metering and improper air-fuel mixture preparation. The paper describes the process of creating toxic components in the exhaust gases of piston engines during engine operation, and impact on the emission of these components determining the composition of the fuel mixture determined equivalence factor Φ. The principal mechanisms of formation of toxic exhaust gases, in particular nitroge...

  20. Healthcare Technology Management (HTM) of mechanical ventilators by clinical engineers

    OpenAIRE

    Yoshioka, Jun; Nakane, Masaki; Kawamae, Kaneyuki

    2014-01-01

    Mechanical ventilator failures expose patients to unacceptable risks, and maintaining mechanical ventilator safety is an important issue. We examined the usefulness of maintaining mechanical ventilators by clinical engineers (CEs) using a specialized calibrator. These evaluations and the ability to make in-house repairs proved useful for obviating the need to rent ventilators which, in turn, might prove faulty themselves. The CEs' involvement in maintaining mechanical ventilators is desirable...

  1. Welcoming speech from Dean Faculty of Mechanical Engineering, UMP

    Science.gov (United States)

    Taha, Zahari

    2012-09-01

    In the Name of Allah, the Most Beneficent, the Most Merciful. It is with great pleasure that I welcome the participants of the International Conference of Mechanical Engineering Research 2011. The Prophet Muhammad (peace be upon him) said 'Acquire knowledge and impart it to the people.' (Al Tirmidhi). The quest for knowledge has been from the beginning of time but knowledge only becomes valuable when it is disseminated and applied to benefit humankind. It is hoped that ICMER 2011 will be a platform to gather and disseminate the latest knowledge in mechanical engineering. Academicians, Scientist, Researchers and practitioners of mechanical engineering will be able to share and discuss new findings and applications of mechanical engineering. It is envisaged that the intellectual discourse will result in future collaborations between universities, research institutions and industry both locally and internationally. In particular it is expected that focus will be given to issues on environmental and energy sustainability. Researchers in the mechanical engineering faculty at UMP have a keen interest in technology to harness energy from the ocean. Lowering vehicle emissions has been a primary goal of researchers in the mechanical engineering faculty and the automotive engineering centre as well including developing vehicles using alternative fuels such as biodiesel and renewable sources such as solar driven electric vehicles. Finally I would like to congratulate the organizing committee for their tremendous efforts in organizing the conference. As I wrote this in the Holy Land of Makkah, I pray to Allah swt that the conference will be a success. Prof. Dr. Zahari Taha CEng, MIED, FASc Dean, Faculty of Mechanical Engineering Universiti Malaysia Pahang

  2. The Purdue Mechanics Freeform Classroom: A New Approach to Engineering Mechanics Education

    OpenAIRE

    Rhoads, Jeffrey F.; Nauman, Eric; Holloway, Beth M; Krousgrill, Charles Morton

    2014-01-01

    The [REMOVED] Mechanics Freeform Classroom: A New Approach to Engineering Mechanics EducationMotivated by the need to address the broad spectrum of learning styles embraced by today’sengineering students, a desire to encourage active, peer-to-peer, and self-learning, and a goal ofinteracting with every student despite ever-expanding enrollments, the mechanics faculty at[REMOVED] University have developed the [REMOVED] Mechanics Freeform Classroom(PMFC) -- a new approach to engineering mechani...

  3. Latest progress of soft rock mechanics and engineering in China

    Directory of Open Access Journals (Sweden)

    Manchao He

    2014-06-01

    Full Text Available The progress of soft rock mechanics and associated technology in China is basically accompanied by the development of mining engineering and the increasing disasters of large rock deformation during construction of underground engineering. In this regard, Chinese scholars proposed various concepts and classification methods for soft rocks in terms of engineering practices. The large deformation mechanism of engineering soft rocks is to be understood through numerous experiments; and thus a coupled support theory for soft rock roadways is established, followed by the development of a new support material, i.e. the constant resistance and large deformation bolt/anchor with negative Poisson's ratio effect, and associated control technology. Field results show that large deformation problems related to numbers of engineering cases can be well addressed with this new technology, an effective way for similar soft rock deformation control.

  4. System dynamics an introduction for mechanical engineers

    CERN Document Server

    Seeler, Karl A

    2014-01-01

    This essential textbook takes the student from the initial steps in modeling a dynamic system through development of the mathematical models needed for feedback control.  The generously-illustrated, student-friendly text focuses on fundamental theoretical development rather than the application of commercial software.  Practical details of machine design are included to motivate the non-mathematically inclined student. This book also: Emphasizes the linear graph method for modeling dynamic systems Offers a systematic approach for creating an engineering model, extracting information, and formulating mathematical analyses Adopts a unifying theme of power flow as the dynamic agent that eases analysis of hybrid systems, such as machinery Presents differential equations as dynamic operators and stresses input/output relationships Introduces Mathcad and programming in MATLAB Allows for use of Open Source Computational Software (R or C) Features over 1000 illustrations

  5. 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;}

  6. Mathematical concepts for mechanical engineering design

    CERN Document Server

    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

  7. Blow molding electric drives of Mechanical Engineering

    Science.gov (United States)

    Bukhanov, S. S.; Ramazanov, M. A.; Tsirkunenko, A. T.

    2018-03-01

    The article considers the questions about the analysis of new possibilities, which gives the use of adjustable electric drives for blowing mechanisms of plastic production. Thus, the use of new semiconductor converters makes it possible not only to compensate the instability of the supply network by using special dynamic voltage regulators, but to improve (correct) the power factor. The calculation of economic efficiency in controlled electric drives of blowing mechanisms is given. On the basis of statistical analysis, the calculation of the reliability parameters of the regulated electric drives’ elements under consideration is given. It is shown that an increase in the reliability of adjustable electric drives is possible both due to overestimation of the electric drive’s installed power, and in simpler schemes with pulse-vector control.

  8. Proper body mechanics from an engineering perspective.

    Science.gov (United States)

    Mohr, Edward G

    2010-04-01

    The economic viability of the manual therapy practitioner depends on the number of massages/treatments that can be given in a day or week. Fatigue or injuries can have a major impact on the income potential and could ultimately reach the point which causes the practitioner to quit the profession, and seek other, less physically demanding, employment. Manual therapy practitioners in general, and massage therapists in particular, can utilize a large variety of body postures while giving treatment to a client. The hypothesis of this paper is that there is an optimal method for applying force to the client, which maximizes the benefit to the client, and at the same time minimizes the strain and effort required by the practitioner. Two methods were used to quantifiably determine the effect of using "poor" body mechanics (Improper method) and "best" body mechanics (Proper/correct method). The first approach uses computer modeling to compare the two methods. Both postures were modeled, such that the biomechanical effects on the practitioner's elbow, shoulder, hip, knee and ankle joints could be calculated. The force applied to the client, along with the height and angle of application of the force, was held constant for the comparison. The second approach was a field study of massage practitioners (n=18) to determine their maximal force capability, again comparing methods using "Improper and Proper body mechanics". Five application methods were tested at three different application heights, using a digital palm force gauge. Results showed that there was a definite difference between the two methods, and that the use of correct body mechanics can have a large impact on the health and well being of the massage practitioner over both the short and long term. Copyright 2009 Elsevier Ltd. All rights reserved.

  9. Engineering mechanical microenvironment of macrophage and its biomedical applications.

    Science.gov (United States)

    Li, Jing; Li, Yuhui; Gao, Bin; Qin, Chuanguang; He, Yining; Xu, Feng; Yang, Hui; Lin, Min

    2018-03-01

    Macrophages are the most plastic cells in the hematopoietic system and can be widely found in almost all tissues. Recently studies have shown that mechanical cues (e.g., matrix stiffness and stress/strain) can significantly affect macrophage behaviors. Although existing reviews on the physical and mechanical cues that regulate the macrophage's phenotype are available, engineering mechanical microenvironment of macrophages in vitro as well as a comprehensive overview and prospects for their biomedical applications (e.g., tissue engineering and immunotherapy) has yet to be summarized. Thus, this review provides an overview on the existing methods for engineering mechanical microenvironment of macrophages in vitro and then a section on their biomedical applications and further perspectives are presented.

  10. Engineering a General Education Program: Designing Mechanical Engineering General Education Courses

    Science.gov (United States)

    Fagette, Paul; Chen, Shih-Jiun; Baran, George R.; Samuel, Solomon P.; Kiani, Mohammad F.

    2013-01-01

    The Department of Mechanical Engineering at our institution created two engineering courses for the General Education Program that count towards second level general science credit (traditional science courses are first level). The courses were designed for the general student population based upon the requirements of our General Education Program…

  11. Control Engineering as a Part of Undergraduate Curriculum for Mechanical Engineering in India

    Science.gov (United States)

    Akhtar, Shagil; Iqbal, Syed Muneeb; Bajpai, Shrish

    2016-01-01

    In this present study we have traced the genesis of control engineering in the scope of mechanical engineering and then some analysis on its recent developments, their increasing need and how this particular subject has evolved machines functioning nowadays specifically its standard of education in India. We have probed this field right from its…

  12. Deconstructing Engineering Education Programmes: The DEEP Project to Reform the Mechanical Engineering Curriculum

    Science.gov (United States)

    Busch-Vishniac, Ilene; Kibler, Tom; Campbell, Patricia B.; Patterson, Eann; Guillaume, Darrell; Jarosz, Jeffrey; Chassapis, Constantin; Emery, Ashley; Ellis, Glenn; Whitworth, Horace; Metz, Susan; Brainard, Suzanne; Ray, Pradosh

    2011-01-01

    The goal of the Deconstructing Engineering Education Programmes project is to revise the mechanical engineering undergraduate curriculum to make the discipline more able to attract and retain a diverse community of students. The project seeks to reduce and reorder the prerequisite structure linking courses to offer greater flexibility for…

  13. Sputtering. [as deposition technique in mechanical engineering

    Science.gov (United States)

    Spalvins, T.

    1976-01-01

    This paper primarily reviews the potential of using the sputtering process as a deposition technique; however, the manufacturing and sputter etching aspects are also discussed. Since sputtering is not regulated by classical thermodynamics, new multicomponent materials can be developed in any possible chemical composition. The basic mechanism for dc and rf sputtering is described. Sputter-deposition is described in terms of the unique advantageous features it offers such as versatility, momentum transfer, stoichiometry, sputter-etching, target geometry (coating complex surfaces), precise controls, flexibility, ecology, and sputtering rates. Sputtered film characteristics, such as strong adherence and coherence and film morphology, are briefly evaluated in terms of varying the sputtering parameters. Also described are some of the specific industrial areas which are turning to sputter-deposition techniques.

  14. Cell Patterning for Liver Tissue Engineering via Dielectrophoretic Mechanisms

    Directory of Open Access Journals (Sweden)

    Wan Nurlina Wan Yahya

    2014-07-01

    Full Text Available Liver transplantation is the most common treatment for patients with end-stage liver failure. However, liver transplantation is greatly limited by a shortage of donors. Liver tissue engineering may offer an alternative by providing an implantable engineered liver. Currently, diverse types of engineering approaches for in vitro liver cell culture are available, including scaffold-based methods, microfluidic platforms, and micropatterning techniques. Active cell patterning via dielectrophoretic (DEP force showed some advantages over other methods, including high speed, ease of handling, high precision and being label-free. This article summarizes liver function and regenerative mechanisms for better understanding in developing engineered liver. We then review recent advances in liver tissue engineering techniques and focus on DEP-based cell patterning, including microelectrode design and patterning configuration.

  15. International Joint Conference on Mechanics, Design Engineering & Advanced Manufacturing

    CERN Document Server

    Nigrelli, Vincenzo; Oliveri, Salvatore; Peris-Fajarnes, Guillermo; Rizzuti, Sergio

    2017-01-01

    This book gathers papers presented at the International Joint Conference on Mechanics, Design Engineering and Advanced Manufacturing (JCM 2016), held on 14-16 September, 2016, in Catania, Italy. It reports on cutting-edge topics in product design and manufacturing, such as industrial methods for integrated product and process design; innovative design; and computer-aided design. Further topics covered include virtual simulation and reverse engineering; additive manufacturing; product manufacturing; engineering methods in medicine and education; representation techniques; and nautical, aeronautics and aerospace design and modeling. The book is divided into eight main sections, reflecting the focus and primary themes of the conference. The contributions presented here will not only provide researchers, engineers and experts in a range of industrial engineering subfields with extensive information to support their daily work; they are also intended to stimulate new research directions, advanced applications of t...

  16. Mechanical design criteria for intervertebral disc tissue engineering.

    Science.gov (United States)

    Nerurkar, Nandan L; Elliott, Dawn M; Mauck, Robert L

    2010-04-19

    Due to the inability of current clinical practices to restore function to degenerated intervertebral discs, the arena of disc tissue engineering has received substantial attention in recent years. Despite tremendous growth and progress in this field, translation to clinical implementation has been hindered by a lack of well-defined functional benchmarks. Because successful replacement of the disc is contingent upon replication of some or all of its complex mechanical behaviors, it is critically important that disc mechanics be well characterized in order to establish discrete functional goals for tissue engineering. In this review, the key functional signatures of the intervertebral disc are discussed and used to propose a series of native tissue benchmarks to guide the development of engineered replacement tissues. These benchmarks include measures of mechanical function under tensile, compressive, and shear deformations for the disc and its substructures. In some cases, important functional measures are identified that have yet to be measured in the native tissue. Ultimately, native tissue benchmark values are compared to measurements that have been made on engineered disc tissues, identifying where functional equivalence was achieved, and where there remain opportunities for advancement. Several excellent reviews exist regarding disc composition and structure, as well as recent tissue engineering strategies; therefore this review will remain focused on the functional aspects of disc tissue engineering. Copyright 2009 Elsevier Ltd. All rights reserved.

  17. Introduction to Analytical Methods for Internal Combustion Engine Cam Mechanisms

    CERN Document Server

    Williams, J J

    2013-01-01

    Modern design methods of Automotive Cam Design require the computation of a range of parameters. This book provides a logical sequence of steps for the derivation of the relevant equations from first principles, for the more widely used cam mechanisms. Although originally derived for use in high performance engines, this work is equally applicable to the design of mass produced automotive and other internal combustion engines.   Introduction to Analytical Methods for Internal Combustion Engine Cam Mechanisms provides the equations necessary for the design of cam lift curves with an associated smooth acceleration curve. The equations are derived for the kinematics and kinetics of all the mechanisms considered, together with those for cam curvature and oil entrainment velocity. This permits the cam shape, all loads, and contact stresses to be evaluated, and the relevant tribology to be assessed. The effects of asymmetry on the manufacture of cams for finger follower and offset translating curved followers is ...

  18. Engineering three-dimensional cell mechanical microenvironment with hydrogels.

    Science.gov (United States)

    Huang, Guoyou; Wang, Lin; Wang, Shuqi; Han, Yulong; Wu, Jinhui; Zhang, Qiancheng; Xu, Feng; Lu, Tian Jian

    2012-12-01

    Cell mechanical microenvironment (CMM) significantly affects cell behaviors such as spreading, migration, proliferation and differentiation. However, most studies on cell response to mechanical stimulation are based on two-dimensional (2D) planar substrates, which cannot mimic native three-dimensional (3D) CMM. Accumulating evidence has shown that there is a significant difference in cell behavior in 2D and 3D microenvironments. Among the materials used for engineering 3D CMM, hydrogels have gained increasing attention due to their tunable properties (e.g. chemical and mechanical properties). In this paper, we provide an overview of recent advances in engineering hydrogel-based 3D CMM. Effects of mechanical cues (e.g. hydrogel stiffness and externally induced stress/strain in hydrogels) on cell behaviors are described. A variety of approaches to load mechanical stimuli in 3D hydrogel-based constructs are also discussed.

  19. Engineering three-dimensional cell mechanical microenvironment with hydrogels

    International Nuclear Information System (INIS)

    Huang Guoyou; Wang Lin; Han Yulong; Zhang Qiancheng; Xu Feng; Lu Tianjian; Wang Shuqi; Wu Jinhui

    2012-01-01

    Cell mechanical microenvironment (CMM) significantly affects cell behaviors such as spreading, migration, proliferation and differentiation. However, most studies on cell response to mechanical stimulation are based on two-dimensional (2D) planar substrates, which cannot mimic native three-dimensional (3D) CMM. Accumulating evidence has shown that there is a significant difference in cell behavior in 2D and 3D microenvironments. Among the materials used for engineering 3D CMM, hydrogels have gained increasing attention due to their tunable properties (e.g. chemical and mechanical properties). In this paper, we provide an overview of recent advances in engineering hydrogel-based 3D CMM. Effects of mechanical cues (e.g. hydrogel stiffness and externally induced stress/strain in hydrogels) on cell behaviors are described. A variety of approaches to load mechanical stimuli in 3D hydrogel-based constructs are also discussed. (topical review)

  20. 46 CFR 113.35-15 - Mechanical engine order telegraph systems; application.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Mechanical engine order telegraph systems; application...) ELECTRICAL ENGINEERING COMMUNICATION AND ALARM SYSTEMS AND EQUIPMENT Engine Order Telegraph Systems § 113.35-15 Mechanical engine order telegraph systems; application. If a mechanical engine order telegraph...

  1. Thermodynamic and Mechanical Analysis of a Thermomagnetic Rotary Engine

    International Nuclear Information System (INIS)

    Fajar, D M; Khotimah, S N; Khairurrijal

    2016-01-01

    A heat engine in magnetic system had three thermodynamic coordinates: magnetic intensity ℋ, total magnetization ℳ, and temperature T, where the first two of them are respectively analogous to that of gaseous system: pressure P and volume V. Consequently, Carnot cycle that constitutes the principle of a heat engine in gaseous system is also valid on that in magnetic system. A thermomagnetic rotary engine is one model of it that was designed in the form of a ferromagnetic wheel that can rotates because of magnetization change at Curie temperature. The study is aimed to describe the thermodynamic and mechanical analysis of a thermomagnetic rotary engine and calculate the efficiencies. In thermodynamic view, the ideal processes are isothermal demagnetization, adiabatic demagnetization, isothermal magnetization, and adiabatic magnetization. The values of thermodynamic efficiency depend on temperature difference between hot and cold reservoir. In mechanical view, a rotational work is determined through calculation of moment of inertia and average angular speed. The value of mechanical efficiency is calculated from ratio between rotational work and heat received by system. The study also obtains exergetic efficiency that states the performance quality of the engine. (paper)

  2. Thermodynamic and Mechanical Analysis of a Thermomagnetic Rotary Engine

    Science.gov (United States)

    Fajar, D. M.; Khotimah, S. N.; Khairurrijal

    2016-08-01

    A heat engine in magnetic system had three thermodynamic coordinates: magnetic intensity ℋ, total magnetization ℳ, and temperature T, where the first two of them are respectively analogous to that of gaseous system: pressure P and volume V. Consequently, Carnot cycle that constitutes the principle of a heat engine in gaseous system is also valid on that in magnetic system. A thermomagnetic rotary engine is one model of it that was designed in the form of a ferromagnetic wheel that can rotates because of magnetization change at Curie temperature. The study is aimed to describe the thermodynamic and mechanical analysis of a thermomagnetic rotary engine and calculate the efficiencies. In thermodynamic view, the ideal processes are isothermal demagnetization, adiabatic demagnetization, isothermal magnetization, and adiabatic magnetization. The values of thermodynamic efficiency depend on temperature difference between hot and cold reservoir. In mechanical view, a rotational work is determined through calculation of moment of inertia and average angular speed. The value of mechanical efficiency is calculated from ratio between rotational work and heat received by system. The study also obtains exergetic efficiency that states the performance quality of the engine.

  3. Project-Based Laboratory Experiences in Mechanical Engineering

    Directory of Open Access Journals (Sweden)

    Narendra Sharma

    2011-12-01

    Full Text Available In this paper we describe project-based laboratories in Mechanical Engineering designed to provide semester-long team experiences which mimic the real life industrial processes of design, development, testing and optimization. The labs are focused on courses at the sophomore level and thus require special attention to constraints of student backgrounds and experience. This paper describes laboratory projects in Dynamics and Fluid Mechanics.

  4. Basic Gasoline Engine Mechanics. Florida Vocational Program Guide.

    Science.gov (United States)

    University of South Florida, Tampa. Dept. of Adult and Vocational Education.

    This packet contains a program guide and Career Merit Achievement Plan (Career MAP) for the implementation of a basic gasoline engine mechanics program in Florida secondary and postsecondary schools. The program guide describes the program content and structure, provides a program description, lists job titles under the program, and includes a…

  5. Elements of Motivational Structure for Studying Mechanical Engineering

    Science.gov (United States)

    Dubreta, Nikša; Miloš, Damir

    2017-01-01

    The article presents the findings on students' reasons for studying mechanical engineering. These reasons were covered in terms of extrinsic and intrinsic motivation additionally related to selected independent variables of the sample--students' secondary school Grade Point Average, their gender and the socio-economic status. The research was…

  6. A Plastic Damage Mechanics Model for Engineered Cementitious Composites

    DEFF Research Database (Denmark)

    Dick-Nielsen, Lars; Stang, Henrik; Poulsen, Peter Noe

    2007-01-01

    This paper discusses the establishment of a plasticity-based damage mechanics model for Engineered Cementitious Composites (ECC). The present model differs from existing models by combining a matrix and fiber description in order to describe the behavior of the ECC material. The model provides...

  7. Alternative evaluation of innovations’ effectiveness in mechanical engineering

    Science.gov (United States)

    Puryaev, A. S.

    2017-09-01

    The aim of present work is approbation of the developed technique for assessing innovations’ effectiveness. We demonstrate an alternative assessment of innovations’ effectiveness (innovation projects) in mechanical engineering on illustrative example. It is proposed as an alternative to the traditional method technique based on the value concept and the method of “Cash flow”.

  8. Evaluating Risk Awareness in Undergraduate Students Studying Mechanical Engineering

    Science.gov (United States)

    Langdon, G. S.; Balchin, K.; Mufamadi, P.

    2010-01-01

    This paper examines the development of risk awareness among undergraduate students studying mechanical engineering at a South African university. A questionnaire developed at the University of Liverpool was modified and used on students from the first, second and third year cohorts to assess their awareness in the areas of professional…

  9. Engine Fundamentals: Automotive Mechanics Instructional Program. Block 2.

    Science.gov (United States)

    O'Brien, Ralph D.

    The second of six instructional blocks in automotive mechanics, the lessons and supportive information in the document provide a guide for teachers in planning an instructional program in engine fundamentals at the secondary and postsecondary level. The material, as organized, is a suggested sequence of instruction within each block. Each lesson…

  10. Mechanical engineering problems in the TFTR neutral beam system

    International Nuclear Information System (INIS)

    Cannon, D.D.; Bryant, E.H.; Johnson, R.L.; Kim, J.; Queen, C.C.; Schilling, G.

    1975-01-01

    A conceptual design of a prototype beam line for the TFTR Neutral Beam System has been developed. The basic components have been defined, cost estimates prepared, and the necessary development programs identified. Four major mechanical engineering problems, potential solutions and the required development programs are discussed

  11. Mechanical stimulation in the engineering of heart muscle.

    Science.gov (United States)

    Liaw, Norman Yu; Zimmermann, Wolfram-Hubertus

    2016-01-15

    Recreating the beating heart in the laboratory continues to be a formidable bioengineering challenge. The fundamental feature of the heart is its pumping action, requiring considerable mechanical forces to compress a blood filled chamber with a defined in- and outlet. Ventricular output crucially depends on venous loading of the ventricles (preload) and on the force generated by the preloaded ventricles to overcome arterial blood pressure (afterload). The rate of contraction is controlled by the spontaneously active sinus node and transmission of its electrical impulses into the ventricles. The underlying principles for these physiological processes are described by the Frank-Starling mechanism and Bowditch phenomenon. It is essential to consider these principles in the design and evaluation of tissue engineered myocardium. This review focuses on current strategies to evoke mechanical loading in hydrogel-based heart muscle engineering. Copyright © 2015. Published by Elsevier B.V.

  12. A real CDIO mechanical engineering project in 4th semester

    DEFF Research Database (Denmark)

    Lauritsen, Aage Birkkjær

    In the past 6 years at the mechanical engineering study at the Engineering College of Aarhus we have been practicing project work on 4th Semester in the design of energy technology systems. In my presentation, I will give a description of the project, and the thoughts behind; pedagogic......-6 students, and will partly support the general theory being taught in the courses, but will also provide students with skills in teamwork, project work and system building. The pedagogical considerations behind the development of the project are quite simply that students learn best through active work...

  13. 2014 Joint Conference on Mechanical Design Engineering and Advanced Manufacturing

    CERN Document Server

    Daidie, Alain; Eynard, Benoit; Paredes, Manuel

    2016-01-01

    Covering key topics in the field such as technological innovation, human-centered sustainable engineering and manufacturing, and manufacture at a global scale in a virtual world, this book addresses both advanced techniques and industrial applications of key research in interactive design and manufacturing. Featuring the full papers presented at the 2014 Joint Conference on Mechanical Design Engineering and Advanced Manufacturing, which took place in June 2014 in Toulouse, France, it presents recent research and industrial success stories related to implementing interactive design and manufacturing solutions.

  14. International Stand of Ukrainian Mechanical Engineering in the European Economy

    Directory of Open Access Journals (Sweden)

    Anastasia A. Goncharova

    2014-03-01

    Full Text Available The article analyses the significant changes in the society that have taken place in Ukraine for the past twenty-five years that considerably influenced the structure and dynamics of mechanical engineering, which, due to objective and subjective reasons, is not ready for large-scale transformational actions. The author has also investigated the dynamics of changes, taking place in the machine-building complex of Ukraine. There have been identified structural changes of the industrial complex that occurred during the crisis and post-crisis period. The article has identified the position of Ukrainian engineering in the European economy.

  15. Contact mechanics of reverse engineered distal humeral hemiarthroplasty implants.

    Science.gov (United States)

    Willing, Ryan; King, Graham J W; Johnson, James A

    2015-11-26

    Erosion of articular cartilage is a concern following distal humeral hemiarthroplasty, because native cartilage surfaces are placed in contact with stiff metallic implant components, which causes decreases in contact area and increases in contact stresses. Recently, reverse engineered implants have been proposed which are intended to promote more natural contact mechanics by reproducing the native bone or cartilage shape. In this study, finite element modeling is used in order to calculate changes in cartilage contact areas and stresses following distal humeral hemiarthroplasty with commercially available and reverse engineered implant designs. At the ulna, decreases in contact area were -34±3% (p=0.002), -27±1% (pengineered and cartilage reverse engineered designs, respectively. Peak contact stresses increased by 461±57% (p=0.008), 387±127% (p=0.229) and 165±16% (p=0.003). At the radius, decreases in contact area were -21±3% (p=0.013), -13±2% (p0.999), 241±32% (p=0.010) and 61±10% (p=0.021). Between the three different implant designs, the cartilage reverse engineered design yielded the largest contact areas and lowest contact stresses, but was still unable to reproduce the contact mechanics of the native joint. These findings align with a growing body of evidence indicating that although reverse engineered hemiarthroplasty implants can provide small improvements in contact mechanics when compared with commercially available designs, further optimization of shape and material properties is required in order reproduce native joint contact mechanics. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Idiopatiske skolioser behandlet med Boston-korset

    DEFF Research Database (Denmark)

    Andersen, M O; Andersen, G R; Kruuse, A M

    1993-01-01

    It is well known that Boston bracing may stop progression in many patients with minor curves. One hundred and thirty-eight patients were treated with the Boston brace for idiopathic scoliosis. Age was 14.1 +/- 1.6 years at the time of bracing, and the length of time spent in the brace was 2.6 +/- 1...

  17. Creating mechanisms of toxic substances emission of combustion engines

    Directory of Open Access Journals (Sweden)

    Jankowski Antoni

    2015-12-01

    Full Text Available The paper analyses the mechanisms of creation of toxic exhaust gases, which mainly derived from inexact fuel metering and improper air-fuel mixture preparation. The paper describes the process of creating toxic components in the exhaust gases of piston engines during engine operation, and impact on the emission of these components determining the composition of the fuel mixture determined equivalence factor Φ. The principal mechanisms of formation of toxic exhaust gases, in particular nitrogen oxides, carbon monoxide and hydrocarbons, and also essential according to create each of toxic exhaust gases are the subject of the paper. Moreover, empirical relationships, by means of which it is possible to determine the time of creation of the individual components of toxic exhaust gases, are presented. For example, one of the mechanisms for prompt formation of nitrogen oxides and hydrocarbons graphic illustration of formation as a function of crank angle is described. At the conclusion, the summary and significance of information on creation mechanisms of toxic components in the exhaust gases of piston engines are presented.

  18. A high throughput mechanical screening device for cartilage tissue engineering.

    Science.gov (United States)

    Mohanraj, Bhavana; Hou, Chieh; Meloni, Gregory R; Cosgrove, Brian D; Dodge, George R; Mauck, Robert L

    2014-06-27

    Articular cartilage enables efficient and near-frictionless load transmission, but suffers from poor inherent healing capacity. As such, cartilage tissue engineering strategies have focused on mimicking both compositional and mechanical properties of native tissue in order to provide effective repair materials for the treatment of damaged or degenerated joint surfaces. However, given the large number design parameters available (e.g. cell sources, scaffold designs, and growth factors), it is difficult to conduct combinatorial experiments of engineered cartilage. This is particularly exacerbated when mechanical properties are a primary outcome, given the long time required for testing of individual samples. High throughput screening is utilized widely in the pharmaceutical industry to rapidly and cost-effectively assess the effects of thousands of compounds for therapeutic discovery. Here we adapted this approach to develop a high throughput mechanical screening (HTMS) system capable of measuring the mechanical properties of up to 48 materials simultaneously. The HTMS device was validated by testing various biomaterials and engineered cartilage constructs and by comparing the HTMS results to those derived from conventional single sample compression tests. Further evaluation showed that the HTMS system was capable of distinguishing and identifying 'hits', or factors that influence the degree of tissue maturation. Future iterations of this device will focus on reducing data variability, increasing force sensitivity and range, as well as scaling-up to even larger (96-well) formats. This HTMS device provides a novel tool for cartilage tissue engineering, freeing experimental design from the limitations of mechanical testing throughput. © 2013 Published by Elsevier Ltd.

  19. Microfabrication of hierarchical structures for engineered mechanical materials

    Science.gov (United States)

    Vera Canudas, Marc

    Materials found in nature present, in some cases, unique properties from their constituents that are of great interest in engineered materials for applications ranging from structural materials for the construction of bridges, canals and buildings to the fabrication of new lightweight composites for airplane and automotive bodies, to protective thin film coatings, amongst other fields. Research in the growing field of biomimetic materials indicates that the micro-architectures present in natural materials are critical to their macroscopic mechanical properties. A better understanding of the effect that structure and hierarchy across scales have on the material properties will enable engineered materials with enhanced properties. At the moment, very few theoretical models predict mechanical properties of simple materials based on their microstructures. Moreover these models are based on observations from complex biological systems. One way to overcome this challenge is through the use of microfabrication techniques to design and fabricate simple materials, more appropriate for the study of hierarchical organizations and microstructured materials. Arrays of structures with controlled geometry and dimension can be designed and fabricated at different length scales, ranging from a few hundred nanometers to centimeters, in order to mimic similar systems found in nature. In this thesis, materials have been fabricated in order to gain fundamental insight into the complex hierarchical materials found in nature and to engineer novel materials with enhanced mechanical properties. The materials fabricated here were mechanically characterized and compared to simple mechanics models to describe their behavior with the goal of applying the knowledge acquired to the design and synthesis of future engineered materials with novel properties.

  20. Combination of biochemical and mechanical cues for tendon tissue engineering.

    Science.gov (United States)

    Testa, Stefano; Costantini, Marco; Fornetti, Ersilia; Bernardini, Sergio; Trombetta, Marcella; Seliktar, Dror; Cannata, Stefano; Rainer, Alberto; Gargioli, Cesare

    2017-11-01

    Tendinopathies negatively affect the life quality of millions of people in occupational and athletic settings, as well as the general population. Tendon healing is a slow process, often with insufficient results to restore complete endurance and functionality of the tissue. Tissue engineering, using tendon progenitors, artificial matrices and bioreactors for mechanical stimulation, could be an important approach for treating rips, fraying and tissue rupture. In our work, C3H10T1/2 murine fibroblast cell line was exposed to a combination of stimuli: a biochemical stimulus provided by Transforming Growth Factor Beta (TGF-β) and Ascorbic Acid (AA); a three-dimensional environment represented by PEGylated-Fibrinogen (PEG-Fibrinogen) biomimetic matrix; and a mechanical induction exploiting a custom bioreactor applying uniaxial stretching. In vitro analyses by immunofluorescence and mechanical testing revealed that the proposed combined approach favours the organization of a three-dimensional tissue-like structure promoting a remarkable arrangement of the cells and the neo-extracellular matrix, reflecting into enhanced mechanical strength. The proposed method represents a novel approach for tendon tissue engineering, demonstrating how the combined effect of biochemical and mechanical stimuli ameliorates biological and mechanical properties of the artificial tissue compared to those obtained with single inducement. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  1. Interactive training model of TRIZ for mechanical engineers in China

    Science.gov (United States)

    Tan, Runhua; Zhang, Huangao

    2014-03-01

    Innovation is a process of taking an original idea and converting it into a business value, in which the engineers face some inventive problems which can be solved hardly by experience. TRIZ, as a new theory for companies in China, provides both conceptual and procedural knowledge for finding and solving inventive problems. Because the government plays a leading role in the diffusion of TRIZ, too many companies from different industries are waiting to be trained, but the quantity of the trainers mastering TRIZ is incompatible with that requirement. In this context, to improve the training effect, an interactive training model of TRIZ for the mechanical engineers in China is developed and the implementation in the form of training classes is carried out. The training process is divided into 6 phases as follows: selecting engineers, training stage-1, finding problems, training stage-2, finding solutions and summing up. The government, TRIZ institutions and companies to join the programs interact during the process. The government initiates and monitors a project in form of a training class of TRIZ and selects companies to join the programs. Each selected companies choose a few engineers to join the class and supervises the training result. The TRIZ institutions design the training courses and carry out training curriculum. With the beginning of the class, an effective communication channel is established by means of interview, discussion face to face, E-mail, QQ and so on. After two years training practices, the results show that innovative abilities of the engineers to join and pass the final examinations increased distinctly, and most of companies joined the training class have taken congnizance of the power of TRIZ for product innovation. This research proposes an interactive training model of TRIZ for mechanical engineers in China to expedite the knowledge diffusion of TRIZ.

  2. MULTIDISCIPLINARY PROJECTS FOR SECOND YEAR CHEMICAL AND MECHANICAL ENGINEERING STUDENTS

    Directory of Open Access Journals (Sweden)

    MARWAN M. SHAMEL

    2013-04-01

    Full Text Available In the second semester of the second year of a Mechanical Engineering course, students are supposed to take a Module Outside the Main Discipline (MOMD. This module is chosen to be “Product Design Exercise” a module that is offered to Chemical Engineering students at the same stage. The aim was to expose students from both disciplines to an environment in which they are encouraged to interact with and engage team members with a relatively different background. The students were divided into eight groups all comprised of Chemical and Mechanical Engineering students, and they were offered different open-ended projects that were selected to exploit the knowledge developed by the students thus far and they were slightly skewed towards Chemical Engineering. The students demonstrated a high level of cooperation and motivation throughout the period of the project. Effective communication and closing of knowledge gaps were prevalent. At the end of the project period, students produced a journal paper in lieu of the project report.

  3. Catastrophe theory and its application status in mechanical engineering

    Directory of Open Access Journals (Sweden)

    Jinge LIU

    Full Text Available Catastrophe theory is a kind of mathematical method which aims to apply and interpret the discontinuous phenomenon. Since its emergence, it has been widely used to explain a variety of emergent phenomena in the fields of natural science, social science, management science and some other science and technology fields. Firstly, this paper introduces the theory of catastrophe in several aspects, such as its generation, radical principle, basic characteristics and development. Secondly, it summarizes the main applications of catastrophe theory in the field of mechanical engineering, focusing on the research progress of catastrophe theory in revealing catastrophe of rotor vibration state, analyzing friction and wear failure, predicting metal fracture, and so on. Finally, it advises that later development of catastrophe theory should pay more attention to the combination of itself with other traditional nonlinear theories and methods. This paper provides a beneficial reference to guide the application of catastrophe theory in mechanical engineering and related fields for later research.

  4. Fuzzy commutative algebra and its application in mechanical engineering

    International Nuclear Information System (INIS)

    Han, J.; Song, H.

    1996-01-01

    Based on literature data, this paper discusses the whole mathematical structure about point-fuzzy number set F(R). By introducing some new operations about addition, subtraction, multiplication, division and scalar multiplication, we prove that F(R) can form fuzzy linear space, fuzzy commutative ring, fuzzy commutative algebra in order. Furthermore, we get that A is fuzzy commutative algebra for any fuzzy subset. At last, we give an application of point-fuzzy number to mechanical engineering

  5. The Application of Problem-Based Learning in Mechanical Engineering

    Science.gov (United States)

    Putra, Z. A.; Dewi, M.

    2018-02-01

    The course of Technology and Material Testing prepare students with the ability to do a variety of material testing in the study of mechanical engineering. Students find it difficult to understand the materials to make them unable to carry out the material testing in accordance with the purpose of study. This happens because they knowledge is not adequately supported by the competence to find and construct learning experience. In this study, quasy experiment research method with pre-post-test with control group design was used. The subjects of the study were students divided in two groups; control and experiment with twenty-two students in each group. Study result: their grades showed no difference in between the pre-test or post-test in control group, but the difference in grade existed between the pre-test and post-test in experiment group. Yet, there is no significant difference in the study result on both groups. The researcher recommend that it is necessary to develop Problem-Based Learning that suits need analysis on D3 Program for Mechanical Engineering Department at the State University of Padang, to ensure the compatibility between Model of Study and problems and need. This study aims to analyze how Problem-Based Learning effects on the course of Technology and Material Testing for the students of D3 Program of Mechanical Engineering of the State University of Padang.

  6. Channelled scaffolds for engineering myocardium with mechanical stimulation.

    Science.gov (United States)

    Zhang, Ting; Wan, Leo Q; Xiong, Zhuo; Marsano, Anna; Maidhof, Robert; Park, Miri; Yan, Yongnian; Vunjak-Novakovic, Gordana

    2012-10-01

    The characteristics of the matrix (composition, structure, mechanical properties) and external culture environment (pulsatile perfusion, physical stimulation) of the heart are important characteristics in the engineering of functional myocardial tissue. This study reports on the development of chitosan-collagen scaffolds with micropores and an array of parallel channels (~ 200 µm in diameter) that were specifically designed for cardiac tissue engineering using mechanical stimulation. The scaffolds were designed to have similar structural and mechanical properties of those of native heart matrix. Scaffolds were seeded with neonatal rat heart cells and subjected to dynamic tensile stretch using a custom designed bioreactor. The channels enhanced oxygen transport and facilitated the establishment of cell connections within the construct. The myocardial patches (14 mm in diameter, 1-2 mm thick) consisted of metabolically active cells that began to contract synchronously after 3 days of culture. Mechanical stimulation with high tensile stress promoted cell alignment, elongation, and expression of connexin-43 (Cx-43). This study confirms the importance of scaffold design and mechanical stimulation for the formation of contractile cardiac constructs. Copyright © 2011 John Wiley & Sons, Ltd.

  7. Channeled Scaffolds for Engineering Myocardium with Mechanical Stimulation

    Science.gov (United States)

    Zhang, Ting; Wan, Leo Q.; Xiong, Zhuo; Marsano, Anna; Maidhof, Robert; Park, Miri; Yan, Yongnian; Vunjak-Novakovic, Gordana

    2011-01-01

    The characteristics of the matrix (composition, structure, mechanical properties) and external culture environment (pulsatile perfusion, physical stimulation) are critically important for engineering functional myocardial tissue. We report the development of chitosan-collagen scaffolds with micro-pores and an array of parallel channels (~200 μm in diameter) that were specifically designed for cardiac tissue engineering with mechanical stimulation. The scaffolds were designed to have the structural and mechanical properties similar to those of the native human heart matrix. Scaffolds were seeded with neonatal rat heart cells and subjected to dynamic tensile stretch using a custom-designed bioreactor. The channels enhanced oxygen transport and facilitated the establishment of cell connections within the construct. The myocardial patches (14 mm in diameter, 1–2 mm thick) consisted of metabolically active cells and started to contract synchronously after 3 days of culture. Mechanical stimulation with high tensile stresses promoted cell alignment, elongation, and the expression of connexin-43 (Cx-43). This study confirms the importance of scaffold design and mechanical stimulation for the formation of contractile cardiac constructs. PMID:22081518

  8. Reliability design of mechanical systems a guide for mechanical and civil engineers

    CERN Document Server

    Woo, Seongwoo

    2017-01-01

    This book describes basic reliability concepts – parametric ALT plan, failure mechanism and design, and reliability testing with acceleration factor and sample size equation. A generalized life-stress failure model with a new effort concept has been derived and recommended to calculate the acceleration factor of the mechanical system. The new sample size equation with the acceleration factor has also been derived to carry out the parametric ALT. This new parametric ALT should help a mechanical/civil engineer to uncover the design parameters affecting reliability during the design process of the mechanical system. Consequently, it should help companies to improve product reliability and avoid recalls due to the product/structure failures in the field. As the improper or missing design parameters in the design phase are experimentally identified by this new reliability design method - parametric ALT, the mechanical/civil engineering system might improve in reliability by the increase in lifetime and the reduc...

  9. Mechanical stimulation improves tissue-engineered human skeletal muscle

    Science.gov (United States)

    Powell, Courtney A.; Smiley, Beth L.; Mills, John; Vandenburgh, Herman H.

    2002-01-01

    Human bioartificial muscles (HBAMs) are tissue engineered by suspending muscle cells in collagen/MATRIGEL, casting in a silicone mold containing end attachment sites, and allowing the cells to differentiate for 8 to 16 days. The resulting HBAMs are representative of skeletal muscle in that they contain parallel arrays of postmitotic myofibers; however, they differ in many other morphological characteristics. To engineer improved HBAMs, i.e., more in vivo-like, we developed Mechanical Cell Stimulator (MCS) hardware to apply in vivo-like forces directly to the engineered tissue. A sensitive force transducer attached to the HBAM measured real-time, internally generated, as well as externally applied, forces. The muscle cells generated increasing internal forces during formation which were inhibitable with a cytoskeleton depolymerizer. Repetitive stretch/relaxation for 8 days increased the HBAM elasticity two- to threefold, mean myofiber diameter 12%, and myofiber area percent 40%. This system allows engineering of improved skeletal muscle analogs as well as a nondestructive method to determine passive force and viscoelastic properties of the resulting tissue.

  10. Mechanics and model-based control of advanced engineering systems

    CERN Document Server

    Irschik, Hans; Krommer, Michael

    2014-01-01

    Mechanics and Model-Based Control of Advanced Engineering Systems collects 32 contributions presented at the International Workshop on Advanced Dynamics and Model Based Control of Structures and Machines, which took place in St. Petersburg, Russia in July 2012. The workshop continued a series of international workshops, which started with a Japan-Austria Joint Workshop on Mechanics and Model Based Control of Smart Materials and Structures and a Russia-Austria Joint Workshop on Advanced Dynamics and Model Based Control of Structures and Machines. In the present volume, 10 full-length papers based on presentations from Russia, 9 from Austria, 8 from Japan, 3 from Italy, one from Germany and one from Taiwan are included, which represent the state of the art in the field of mechanics and model based control, with particular emphasis on the application of advanced structures and machines.

  11. Experiments in Creative Engineering at the Department of Mechanical Engineering in Kurume National College of Technology

    Science.gov (United States)

    Tanaka, Hiroshi; Hashimura, Shinji; Hiroo, Yasuaki

    We present a program to learn ability to solve problems on engineering. This program is called “Experiments in creative engineering” in the department of mechanical engineering in Kurume National College of Technology advanced engineering school. In the program, students have to determine own theme and manufacture experimental devices or some machines by themselves. The students must also perform experiments to valid the function and performance of their devices by themselves. The restriction of the theme is to manufacture a device which function dose not basically exist in the world with limited cost (up to 20,000Yen) . As the results of questionnaire of students, the program would be very effective to the creative education for the students.

  12. 46 CFR 113.35-13 - Mechanical engine order telegraph systems; operation.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Mechanical engine order telegraph systems; operation...) ELECTRICAL ENGINEERING COMMUNICATION AND ALARM SYSTEMS AND EQUIPMENT Engine Order Telegraph Systems § 113.35-13 Mechanical engine order telegraph systems; operation. If more than one transmitter operates a...

  13. 46 CFR 113.35-9 - Mechanical engine order telegraph systems.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Mechanical engine order telegraph systems. 113.35-9 Section 113.35-9 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING COMMUNICATION AND ALARM SYSTEMS AND EQUIPMENT Engine Order Telegraph Systems § 113.35-9 Mechanical engine order...

  14. Mechanical-engineering aspects of mirror-fusion technology

    International Nuclear Information System (INIS)

    Fisher, D.K.; Doggett, J.N.

    1982-01-01

    The mirror approach to magnetic fusion has evolved from the original simple mirror cell to today's mainline effort: the tandem-mirror machine with thermal barriers. Physics and engineering research is being conducted throughout the world, with major efforts in Japan, the USSR, and the US. At least one facility under construction (MFTF-B) will approach equivalent energy breakeven in physics performance. Significant mechanical engineering development is needed, however, before a demonstration reactor can be constructed. The principal areas crucial to mirror reactor development include large high-field superconducting magnets, high-speed continuous vacuum-pumping systems, long-pulse high-power neutral-beam and rf-plasma heating systems, and efficient high-voltage high-power direct converters. Other areas common to all fusion systems include tritium handling technology, first-wall materials development, and fusion blanket design

  15. Mechanical cues in orofacial tissue engineering and regenerative medicine.

    Science.gov (United States)

    Brouwer, Katrien M; Lundvig, Ditte M S; Middelkoop, Esther; Wagener, Frank A D T G; Von den Hoff, Johannes W

    2015-01-01

    Cleft lip and palate patients suffer from functional, aesthetical, and psychosocial problems due to suboptimal regeneration of skin, mucosa, and skeletal muscle after restorative cleft surgery. The field of tissue engineering and regenerative medicine (TE/RM) aims to restore the normal physiology of tissues and organs in conditions such as birth defects or after injury. A crucial factor in cell differentiation, tissue formation, and tissue function is mechanical strain. Regardless of this, mechanical cues are not yet widely used in TE/RM. The effects of mechanical stimulation on cells are not straight-forward in vitro as cellular responses may differ with cell type and loading regime, complicating the translation to a therapeutic protocol. We here give an overview of the different types of mechanical strain that act on cells and tissues and discuss the effects on muscle, and skin and mucosa. We conclude that presently, sufficient knowledge is lacking to reproducibly implement external mechanical loading in TE/RM approaches. Mechanical cues can be applied in TE/RM by fine-tuning the stiffness and architecture of the constructs to guide the differentiation of the seeded cells or the invading surrounding cells. This may already improve the treatment of orofacial clefts and other disorders affecting soft tissues. © 2015 by the Wound Healing Society.

  16. Engineering the mechanical and biological properties of nanofibrous vascular grafts for in situ vascular tissue engineering.

    Science.gov (United States)

    Henry, Jeffrey J D; Yu, Jian; Wang, Aijun; Lee, Randall; Fang, Jun; Li, Song

    2017-08-17

    Synthetic small diameter vascular grafts have a high failure rate, and endothelialization is critical for preventing thrombosis and graft occlusion. A promising approach is in situ tissue engineering, whereby an acellular scaffold is implanted and provides stimulatory cues to guide the in situ remodeling into a functional blood vessel. An ideal scaffold should have sufficient binding sites for biomolecule immobilization and a mechanical property similar to native tissue. Here we developed a novel method to blend low molecular weight (LMW) elastic polymer during electrospinning process to increase conjugation sites and to improve the mechanical property of vascular grafts. LMW elastic polymer improved the elasticity of the scaffolds, and significantly increased the amount of heparin conjugated to the micro/nanofibrous scaffolds, which in turn increased the loading capacity of vascular endothelial growth factor (VEGF) and prolonged the release of VEGF. Vascular grafts were implanted into the carotid artery of rats to evaluate the in vivo performance. VEGF treatment significantly enhanced endothelium formation and the overall patency of vascular grafts. Heparin coating also increased cell infiltration into the electrospun grafts, thus increasing the production of collagen and elastin within the graft wall. This work demonstrates that LMW elastic polymer blending is an approach to engineer the mechanical and biological property of micro/nanofibrous vascular grafts for in situ vascular tissue engineering.

  17. Mechanisms Engineering Test Loop - Phase 1 Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Kultgen, D. [Argonne National Lab. (ANL), Argonne, IL (United States); Grandy, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Hvasta, M. [Argonne National Lab. (ANL), Argonne, IL (United States); Lisowski, D. [Argonne National Lab. (ANL), Argonne, IL (United States); Toter, W. [Argonne National Lab. (ANL), Argonne, IL (United States); Borowski, A. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-09-01

    This report documents the current status of the Mechanisms Engineering Test Loop (METL) as of the end of FY2016. Currently, METL is in Phase I of its design and construction. Once operational, the METL facility will test small to intermediate-scale components and systems in order to develop advanced liquid metal technologies. Testing different components in METL is essential for the future of advanced fast reactors as it will provide invaluable performance data and reduce the risk of failures during plant operation.

  18. The Code Aster: a product for mechanical engineers

    International Nuclear Information System (INIS)

    Levesque, J.R.

    1998-01-01

    The Code Aster is a 2D or 3D structural finite element software: analysis of structures and thermo-mechanics for evaluation and research with linear for non linear modelling. Since 1989, it has been the host structure that capitalizes on developments made by the Research and Development Division in the field of numerical modelling in structural mechanics, and user experience feedback. It is an industrial design tool, particularly for engineering of facilities in operation and for the evaluation of new projects. This software was developed using a quality Assurance methodology with independent validation. Upgrades to this product are guided by the objective of satisfying the needs of expertise studies, attempting to make functions coherent and complete. (author)

  19. Interactive simulations as teaching tools for engineering mechanics courses

    Science.gov (United States)

    Carbonell, Victoria; Romero, Carlos; Martínez, Elvira; Flórez, Mercedes

    2013-07-01

    This study aimed to gauge the effect of interactive simulations in class as an active teaching strategy for a mechanics course. Engineering analysis and design often use the properties of planar sections in calculations. In the stress analysis of a beam under bending and torsional loads, cross-sectional properties are used to determine stress and displacement distributions in the beam cross section. The centroid, moments and products of inertia of an area made up of several common shapes (rectangles usually) may thus be obtained by adding the moments of inertia of the component areas (U-shape, L-shape, C-shape, etc). This procedure is used to calculate the second moments of structural shapes in engineering practice because the determination of their moments of inertia is necessary for the design of structural components. This paper presents examples of interactive simulations developed for teaching the ‘Mechanics and mechanisms’ course at the Universidad Politecnica de Madrid, Spain. The simulations focus on fundamental topics such as centroids, the properties of the moment of inertia, second moments of inertia with respect to two axes, principal moments of inertia and Mohr's Circle for plane stress, and were composed using Geogebra software. These learning tools feature animations, graphics and interactivity and were designed to encourage student participation and engagement in active learning activities, to effectively explain and illustrate course topics, and to build student problem-solving skills.

  20. Elements of Motivational Structure for Studying Mechanical Engineering

    Directory of Open Access Journals (Sweden)

    Nikša Dubreta

    2017-12-01

    Full Text Available The article presents the findings on students' reasons for studying mechanical engineering. These reasons were covered in terms of extrinsic and intrinsic motivation additionally related to selected independent variables of the sample – students' secondary school Grade Point Average, their gender and the socio-economic status. The research was conducted with the first year students of the Faculty of Mechanical Engineering at the University of Zagreb, Croatia. The sample consisted of 282 students (228 males and 54 females and comprised students of all majors. According to descriptive character of the questionnaire type survey characteristics of the sample are presented. Composite variables of extrinsic and intrinsic motivation were dichotomized to present different levels of the students' overall motivational structure. Results indicate a students' interest in the field of science and technology as the most important element of intrinsic motivation, with no significant relation to any of independent variables. By contrast, extrinsic motivation has manifested as significantly related to the variables of Grade Point Average and to parents' education as one component of the socio-economic status. However, a significant level of indecisive respondents regarding the both intrinsic and extrinsic motivation suggests that the choice of the study programme is not always a consistent and an unambiguous process.

  1. Interactive simulations as teaching tools for engineering mechanics courses

    International Nuclear Information System (INIS)

    Carbonell, Victoria; Martínez, Elvira; Flórez, Mercedes; Romero, Carlos

    2013-01-01

    This study aimed to gauge the effect of interactive simulations in class as an active teaching strategy for a mechanics course. Engineering analysis and design often use the properties of planar sections in calculations. In the stress analysis of a beam under bending and torsional loads, cross-sectional properties are used to determine stress and displacement distributions in the beam cross section. The centroid, moments and products of inertia of an area made up of several common shapes (rectangles usually) may thus be obtained by adding the moments of inertia of the component areas (U-shape, L-shape, C-shape, etc). This procedure is used to calculate the second moments of structural shapes in engineering practice because the determination of their moments of inertia is necessary for the design of structural components. This paper presents examples of interactive simulations developed for teaching the ‘Mechanics and mechanisms’ course at the Universidad Politecnica de Madrid, Spain. The simulations focus on fundamental topics such as centroids, the properties of the moment of inertia, second moments of inertia with respect to two axes, principal moments of inertia and Mohr's Circle for plane stress, and were composed using Geogebra software. These learning tools feature animations, graphics and interactivity and were designed to encourage student participation and engagement in active learning activities, to effectively explain and illustrate course topics, and to build student problem-solving skills. (paper)

  2. Tunable engineered skin mechanics via coaxial electrospun fiber core diameter.

    Science.gov (United States)

    Blackstone, Britani Nicole; Drexler, Jason William; Powell, Heather Megan

    2014-10-01

    Autologous engineered skin (ES) offers promise as a treatment for massive full thickness burns. Unfortunately, ES is orders of magnitude weaker than normal human skin causing it to be difficult to apply surgically and subject to damage by mechanical shear in the early phases of engraftment. In addition, no manufacturing strategy has been developed to tune ES biomechanics to approximate the native biomechanics at different anatomic locations. To enhance and tune ES biomechanics, a coaxial (CoA) electrospun scaffold platform was developed from polycaprolactone (PCL, core) and gelatin (shell). The ability of the coaxial fiber core diameter to control both scaffold and tissue mechanics was investigated along with the ability of the gelatin shell to facilitate cell adhesion and skin development compared to pure gelatin, pure PCL, and a gelatin-PCL blended fiber scaffold. CoA ES exhibited increased cellular adhesion and metabolism versus PCL alone or gelatin-PCL blend and promoted the development of well stratified skin with a dense dermal layer and a differentiated epidermal layer. Biomechanics of the scaffold and ES scaled linearly with core diameter suggesting that this scaffold platform could be utilized to tailor ES mechanics for their intended grafting site and reduce graft damage in vitro and in vivo.

  3. Tunable Engineered Skin Mechanics via Coaxial Electrospun Fiber Core Diameter

    Science.gov (United States)

    Blackstone, Britani Nicole; Drexler, Jason William

    2014-01-01

    Autologous engineered skin (ES) offers promise as a treatment for massive full thickness burns. Unfortunately, ES is orders of magnitude weaker than normal human skin causing it to be difficult to apply surgically and subject to damage by mechanical shear in the early phases of engraftment. In addition, no manufacturing strategy has been developed to tune ES biomechanics to approximate the native biomechanics at different anatomic locations. To enhance and tune ES biomechanics, a coaxial (CoA) electrospun scaffold platform was developed from polycaprolactone (PCL, core) and gelatin (shell). The ability of the coaxial fiber core diameter to control both scaffold and tissue mechanics was investigated along with the ability of the gelatin shell to facilitate cell adhesion and skin development compared to pure gelatin, pure PCL, and a gelatin-PCL blended fiber scaffold. CoA ES exhibited increased cellular adhesion and metabolism versus PCL alone or gelatin-PCL blend and promoted the development of well stratified skin with a dense dermal layer and a differentiated epidermal layer. Biomechanics of the scaffold and ES scaled linearly with core diameter suggesting that this scaffold platform could be utilized to tailor ES mechanics for their intended grafting site and reduce graft damage in vitro and in vivo. PMID:24712409

  4. Multi-axial mechanical stimulation of tissue engineered cartilage: Review

    Directory of Open Access Journals (Sweden)

    S D Waldman

    2007-04-01

    Full Text Available The development of tissue engineered cartilage is a promising new approach for the repair of damaged or diseased tissue. Since it has proven difficult to generate cartilaginous tissue with properties similar to that of native articular cartilage, several studies have used mechanical stimuli as a means to improve the quantity and quality of the developed tissue. In this study, we have investigated the effect of multi-axial loading applied during in vitro tissue formation to better reflect the physiological forces that chondrocytes are subjected to in vivo. Dynamic combined compression-shear stimulation (5% compression and 5% shear strain amplitudes increased both collagen and proteoglycan synthesis (76 ± 8% and 73 ± 5%, respectively over the static (unstimulated controls. When this multi-axial loading condition was applied to the chondrocyte cultures over a four week period, there were significant improvements in both extracellular matrix (ECM accumulation and the mechanical properties of the in vitro-formed tissue (3-fold increase in compressive modulus and 1.75-fold increase in shear modulus. Stimulated tissues were also significantly thinner than the static controls (19% reduction suggesting that there was a degree of ECM consolidation as a result of long-term multi-axial loading. This study demonstrated that stimulation by multi-axial forces can improve the quality of the in vitro-formed tissue, but additional studies are required to further optimize the conditions to favour improved biochemical and mechanical properties of the developed tissue.

  5. Applications of the discrete element method in mechanical engineering

    International Nuclear Information System (INIS)

    Fleissner, Florian; Gaugele, Timo; Eberhard, Peter

    2007-01-01

    Compared to other fields of engineering, in mechanical engineering, the Discrete Element Method (DEM) is not yet a well known method. Nevertheless, there is a variety of simulation problems where the method has obvious advantages due to its meshless nature. For problems where several free bodies can collide and break after having been largely deformed, the DEM is the method of choice. Neighborhood search and collision detection between bodies as well as the separation of large solids into smaller particles are naturally incorporated in the method. The main DEM algorithm consists of a relatively simple loop that basically contains the three substeps contact detection, force computation and integration. However, there exists a large variety of different algorithms to choose the substeps to compose the optimal method for a given problem. In this contribution, we describe the dynamics of particle systems together with appropriate numerical integration schemes and give an overview over different types of particle interactions that can be composed to adapt the method to fit to a given simulation problem. Surface triangulations are used to model complicated, non-convex bodies in contact with particle systems. The capabilities of the method are finally demonstrated by means of application examples

  6. Integrating Technical Communication in the Mechanical Engineering Curriculum

    Science.gov (United States)

    Norberg, Seth; Ashcraft, Timothy; van Poppel, Bret

    2017-11-01

    Technical communication is essential to engineering practice, but these skills can be challenging to teach and assess in the classroom. Instructors in the Mechanical Engineering (ME) program at the United States Military Academy are developing new learning exercises to prepare students for success in their capstone design course and beyond. In this paper we highlight the recent successes and lessons learned from two courses: junior-level Thermal-Fluid Systems and the senior-level ME Seminar. Both courses support the newly implemented West Point Writing Program (WPWP), an institutional, writing-across-the-curriculum program. The junior course incorporates four hands-on experiments, which provide an abundance of data for students to analyze, assess, and present. In the senior course the majority of the content that students present is from their ongoing capstone design projects. Between the two courses, students craft essays, lab reports, short summaries, posters, quad charts, and technical presentations. Both courses include peer evaluation, revision exercises, and timed (on demand) writing assignments. The junior course includes assignments co-authored by a group as well as an individual report. An overview of both courses' assignments with course-end feedback from the students and the faculty is provided. Strengths and weaknesses are identified and recommendations for instructors seeking to implement similar technical communications assignments in their own courses are presented.

  7. First Year Experiences in School of Mechanical Engineering Kanazawa University

    Science.gov (United States)

    Kinari, Toshiyasu; Kanjin, Yuichi; Furuhata, Toru; Tada, Yukio

    This paper reports two lectures of the first year experience, ‧Lecture on Life in Campus and Society‧ and ‧Freshman Seminar‧ and discusses their effects. Both lectures have been given freshmen of the school of mechanical engineering, Kanazawa University in H20 spring term. The former lecture is aimed at freshmen to keep on a proper way in both social and college life. It consists of normal class and e-learning system lectures. E-learning system examination requires students to review the whole text book and that seems to have brought better results in the survey. The latter seminar is aimed at freshmen to get active and self-disciplined learning way through their investigation, discussion, presentation, writing work, and so on.

  8. Critical Performance of Turbopump Mechanical Elements for Rocket Engine

    Science.gov (United States)

    Takada, Satoshi; Kikuchi, Masataka; Sudou, Takayuki; Iwasaki, Fumiya; Watanabe, Yoshiaki; Yoshida, Makoto

    It is generally acknowledged that bearings and axial seals have a tendency to go wrong compared with other rocket engine elements. And when those components have malfunction, missions scarcely succeed. However, fundamental performance (maximum rotational speed, minimum flow rate, power loss, durability, etc.) of those components has not been grasped yet. Purpose of this study is to grasp a critical performance of mechanical seal and hybrid ball bearing of turbopump. In this result, it was found that bearing outer race temperature and bearing coolant outlet temperature changed along saturation line of liquid hydrogen when flow rate was decreased under critical pressure. And normal operation of bearing was possible under conditions of more than 70,000 rpm of rotational speed and more than 0.2 liter/s of coolant flow rate. Though friction coefficient of seal surface increased several times of original value after testing, the seal showed a good performance same as before.

  9. A concise introduction to mechanics of rigid bodies multidisciplinary engineering

    CERN Document Server

    Huang, L

    2017-01-01

    This updated second edition broadens the explanation of rotational kinematics and dynamics — the most important aspect of rigid body motion in three-dimensional space and a topic of much greater complexity than linear motion. It expands treatment of vector and matrix, and includes quaternion operations to describe and analyze rigid body motion which are found in robot control, trajectory planning, 3D vision system calibration, and hand-eye coordination of robots in assembly work, etc. It features updated treatments of concepts in all chapters and case studies. The textbook retains its comprehensiveness in coverage and compactness in size, which make it easily accessible to the readers from multidisciplinary areas who want to grasp the key concepts of rigid body mechanics which are usually scattered in multiple volumes of traditional textbooks. Theoretical concepts are explained through examples taken from across engineering disciplines and links to applications and more advanced courses (e.g. industrial rob...

  10. Incorporating a Product Archaeology Paradigm across the Mechanical Engineering Curriculum

    Science.gov (United States)

    Moore-Russo, Deborah; Cormier, Phillip; Lewis, Kemper; Devendorf, Erich

    2013-01-01

    Historically, the teaching of design theory in an engineering curriculum has been relegated to a senior capstone design experience. Presently, however, engineering design concepts and courses can be found through the entirety of most engineering programs. Educators have recognized that engineering design provides a foundational platform that can…

  11. Proceedings of the 3. Canada-US rock mechanics symposium and 20. Canadian rock mechanics symposium : rock engineering 2009 : rock engineering in difficult conditions

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    This conference provided a forum for geologists, mining operators and engineers to discuss the application of rock mechanics in engineering designs. Members of the scientific and engineering communities discussed challenges and interdisciplinary elements involved in rock engineering. New geological models and methods of characterizing rock masses and ground conditions in underground engineering projects were discussed along with excavation and mining methods. Papers presented at the conference discussed the role of rock mechanics in forensic engineering. Geophysics, geomechanics, and risk-based approaches to rock engineering designs were reviewed. Issues related to high pressure and high flow water conditions were discussed, and new rock physics models designed to enhance hydrocarbon recovery were presented. The conference featured 84 presentations, of which 9 have been catalogued separately for inclusion in this database. tabs., figs.

  12. Engineering and Design: Reliability Analysis of Navigation Lock and Dam Mechanical and Electrical Equipment

    National Research Council Canada - National Science Library

    Beranek, Dwight

    2001-01-01

    This engineer technical letter (ETL) provides guidance for assessing the reliability of mechanical and electrical systems of navigation locks and dams and for establishing an engineering basis for major rehabilitation investment decisions...

  13. Dynamics and control of mechanical systems in offshore engineering

    CERN Document Server

    He, Wei; How, Bernard Voon Ee; Choo, Yoo Sang

    2014-01-01

    Dynamics and Control of Mechanical Systems in Offshore Engineering is a comprehensive treatment of marine mechanical systems (MMS) involved in processes of great importance such as oil drilling and mineral recovery. Ranging from nonlinear dynamic modeling and stability analysis of flexible riser systems, through advanced control design for an installation system with a single rigid payload attached by thrusters, to robust adaptive control for mooring systems, it is an authoritative reference on the dynamics and control of MMS. Readers will gain not only a complete picture of MMS at the system level, but also a better understanding of the technical considerations involved and solutions to problems that commonly arise from dealing with them. The text provides:                                                                                                                                 ...

  14. A Novel bioreactor with mechanical stimulation for skeletal tissue engineering

    Directory of Open Access Journals (Sweden)

    M. Petrović

    2009-01-01

    Full Text Available The provision of mechanical stimulation is believed to be necessary for the functional assembly of skeletal tissues, which are normally exposed to a variety of biomechanical signals in vivo. In this paper, we present a development and validation of a novel bioreactor aimed for skeletal tissue engineering that provides dynamic compression and perfusion of cultivated tissues. Dynamic compression can be applied at frequencies up to 67.5 Hz and displacements down to 5 m thus suitable for the simulation of physiological conditions in a native cartilage tissue (0.1-1 Hz, 5-10 % strain. The bioreactor also includes a load sensor that was calibrated so to measure average loads imposed on tissue samples. Regimes of the mechanical stimulation and acquisition of load sensor outputs are directed by an automatic control system using applications developed within the LabView platform. In addition, perfusion of tissue samples at physiological velocities (10–100 m/s provides efficient mass transfer, as well as the possibilities to expose the cells to hydrodynamic shear and simulate the conditions in a native bone tissue. Thus, the novel bioreactor is suited for studies of the effects of different biomechanical signals on in vitro regeneration of skeletal tissues, as well as for the studies of newly formulated biomaterials and cell biomaterial interactions under in vivo-like settings.

  15. Primary splenic torsion in a Boston terrier.

    Science.gov (United States)

    OHTA, Hiroshi; TAKAGI, Satoshi; MURAKAMI, Masahiro; SASAKI, Noboru; YOSHIKAWA, Muneyoshi; NAKAMURA, Kensuke; HWANG, Shiang-Jyi; YAMASAKI, Masahiro; TAKIGUCHI, Mitsuyoshi

    2009-11-01

    A 7-year-old female Boston terrier was referred to Hokkaido University Veterinary Teaching Hospital with a history of hemoglobinuria and anemia for several days. Abdominal radiographs showed splenomegaly, and ultrasonography revealed a hypoechoic splenic parenchyma with interspersed linear echoes consistent with the ultrasonographic appearance of splenic torsion. Ultrasonography and computed tomography (CT) indicated a C-shaped spleen. Exploratory laparotomy confirmed the diagnosis of splenic torsion. A splenectomy was performed, and the dog recovered well without complications. This is the first report of splenic torsion in Boston terriers, and the usefulness of ultrasonographic and CT findings of the splenic torsion was also confirmed.

  16. Primary splenic torsion in a Boston terrier

    International Nuclear Information System (INIS)

    Ohta, H.; Takagi, S.; Murakami, M.; Sasaki, N.; Yoshikawa, M.; Nakamura, K.; Hwang, S.J.; Yamasaki, M.; Takiguchi, M.

    2009-01-01

    A 7-year-old female Boston terrier was referred to Hokkaido University Veterinary Teaching Hospital with a history of hemoglobinuria and anemia for several days. Abdominal radiographs showed splenomegaly, and ultrasonography revealed a hypoechoic splenic parenchyma with interspersed linear echoes consistent with the ultrasonographic appearance of splenic torsion. Ultrasonography and computed tomography (CT) indicated a C-shaped spleen. Exploratory laparotomy confirmed the diagnosis of splenic torsion. A splenectomy was performed, and the dog recovered well without complications. This is the first report of splenic torsion in Boston terriers, and the usefulness of ultrasonographic and CT findings of the splenic torsion was also confirmed

  17. Draft fracture mechanics code case for American Society of Mechanical Engineers NUPACK rules

    International Nuclear Information System (INIS)

    McConnell, P.; Sorenson, K.; Nickell, R.; Saegusa, T.

    2004-01-01

    The containment boundaries of most spent-fuel casks certified for use in the United States by the Nuclear Regulatory Commission are constructed with stainless steel, a material that is ductile in an engineering sense at all temperatures and for which, therefore, fracture mechanics principles are not relevant for the containment application. Ferritic materials may fail in a nonductile manner at sufficiently low temperatures, so fracture mechanics principles may be applied to preclude nonductile fracture. Because of the need to transport and store spent nuclear fuel safely in all types of climatic conditions, these vessels have regulatory lowest service temperatures that range down to -40 C (-40 F) for transport application. Such low service temperatures represent a severe challenge in terms of fracture toughness to many ferritic materials. Linear-elastic and elastic-plastic fracture mechanics principles provide a methodology for evaluating ferritic materials under such conditions

  18. Environmental Assessment for Boston Harbor Maintenance Dredging, Boston, Massachusetts.

    Science.gov (United States)

    1981-12-01

    Harbor was developed by Jerome et al (1966), Chesmore et al (1971) and Iwanowicz et al. (1973). The studies on the Lower Mystic River were concentrated in... Iwanowicz et al. (1973) and this data should be referred to for detailed information. Waters overlying the shellfish beds are contaminated by wastes...DMRP Technical Report DS-78-5, Environmental Laboratory, U.S. Army Engineer Waterways Experiment Station, Vicksburg, Mississippi. Iwanowicz , H. R., R D

  19. Analytical expression for an optimised link bar mechanism for a beta-type Stirling engine

    DEFF Research Database (Denmark)

    Carlsen, Henrik; Bovin, Jonas Kabell

    2007-01-01

    The design of a mechanism for kinematic beta-type Stirling engines, where the displacer piston and the working piston share the same cylinder, is complicated. A well-known solution is the rhombic drive, but this solution depends on oil lubrication because of the gear wheels connecting the two...... counter rotating crank shafts. In a hermetically sealed Stirling engine it is an advantage to avoid oil in the crank case, making the application of the rhombic drive difficult. In this paper, another crank mechanism is presented, which has been developed for a 9 kW single cylinder engine. The new crank...... mechanism is a further development of the mechanism in a previous 9 kW engine. The crank mechanism for the beta-type Stirling engine is based on two four-link straight line mechanisms pointing up and down, respectively. The mechanism pointing upwards is connected to the working piston, while the mechanism...

  20. AUTOMOTIVE DIESEL MAINTENANCE 1. UNIT VI, MAINTAINING MECHANICAL GOVERNORS--DETROIT DIESEL ENGINES.

    Science.gov (United States)

    Human Engineering Inst., Cleveland, OH.

    THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE OPERATION AND MAINTENANCE OF MECHANICAL GOVERNORS USED ON DIESEL ENGINES. TOPICS ARE (1) TYPES OF GOVERNORS AND ENGINE LOCATION, (2) GOVERNOR APPLICATIONS, (3) LIMITING SPEED MECHANICAL GOVERNOR, (4) VARIABLE SPEED MECHANICAL GOVERNOR, AND (5) CONSTANT SPEED…

  1. Automotive Engines; Automotive Mechanics I: 9043.03.

    Science.gov (United States)

    Dade County Public Schools, Miami, FL.

    This automotive engines course studies and demonstrates the theory and principles of operation of the automotive four stroke cycle engine. The student will develop an understanding of the systems necessary to make the engine perform as designed, such as cooling, fuel, ignition and lubrication. This is a one or two quinmester credit course of 45…

  2. 78 FR 35756 - Drawbridge Operation Regulations; Charles River, Boston, MA

    Science.gov (United States)

    2013-06-14

    ... Regulations; Charles River, Boston, MA AGENCY: Coast Guard, DHS. ACTION: Notice of temporary deviation from...) Bridge across the Charles River, mile 1.0, at Boston, Massachusetts. Under this temporary deviation the... Metropolitan District Commission (Craigie) Bridge, across the Charles River, mile 1.0, at Boston, Massachusetts...

  3. 2009 National Renewable Energy Laboratory/Boston Redevelopment Authority Topographic LiDAR: Boston, Massachusetts

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Alliance for Sustainable Energy, LLC contracted with Sanborn to provide LiDAR mapping services for the Boston area. Utilizing multi-return systems, Light...

  4. A Systems Engineering Approach to Electro-Mechanical Actuator Diagnostic and Prognostic Development

    Data.gov (United States)

    National Aeronautics and Space Administration — The authors have formulated a Comprehensive Systems Engineering approach to Electro-Mechanical Actuator (EMA) Prognostics and Health Management (PHM) system...

  5. Novel mechanically competent polysaccharide scaffolds for bone tissue engineering

    International Nuclear Information System (INIS)

    Kumbar, S G; Toti, U S; Deng, M; James, R; Laurencin, C T; Aravamudhan, A; Harmon, M; Ramos, D M

    2011-01-01

    The success of the scaffold-based bone regeneration approach critically depends on the biomaterial's mechanical and biological properties. Cellulose and its derivatives are inherently associated with exceptional strength and biocompatibility due to their β-glycosidic linkage and extensive hydrogen bonding. This polymer class has a long medical history as a dialysis membrane, wound care system and pharmaceutical excipient. Recently cellulose-based scaffolds have been developed and evaluated for a variety of tissue engineering applications. In general porous polysaccharide scaffolds in spite of many merits lack the necessary mechanical competence needed for load-bearing applications. The present study reports the fabrication and characterization of three-dimensional (3D) porous sintered microsphere scaffolds based on cellulose derivatives using a solvent/non-solvent sintering approach for load-bearing applications. These 3D scaffolds exhibited a compressive modulus and strength in the mid-range of human trabecular bone and underwent degradation resulting in a weight loss of 10–15% after 24 weeks. A typical stress–strain curve for these scaffolds showed an initial elastic region and a less-stiff post-yield region similar to that of native bone. Human osteoblasts cultured on these scaffolds showed progressive growth with time and maintained expression of osteoblast phenotype markers. Further, the elevated expression of alkaline phosphatase and mineralization at early time points as compared to heat-sintered poly(lactic acid–glycolic acid) control scaffolds with identical pore properties affirmed the advantages of polysaccharides and their potential for scaffold-based bone regeneration.

  6. Mechanical Design Engineering Enabler Project wheel and wheel drives

    Science.gov (United States)

    Nutt, Richard E.; Couch, Britt K.; Holley, John L., Jr.; Garris, Eric S.; Staut, Paul V.

    1992-01-01

    Our group was assigned the responsibility of designing the wheel and wheel drive system for a proof-of-concept model of the lunar-based ENABLER. ENABLER is a multi-purpose, six wheeled vehicle designed to lift and transport heavy objects associated with the construction of a lunar base. The resulting design was based on the performance criteria of the ENABLER. The drive system was designed to enable the vehicle to achieve a speed of 7 mph on a level surface, climb a 30 percent grade, and surpass a one meter high object and one meter wide crevice. The wheel assemblies were designed to support the entire weight of the vehicle on two wheels. The wheels were designed to serve as the main component of the vehicle's suspension and will provide suitable traction for lunar-type surfaces. The expected performance of the drive system for the ENABLER was influenced by many mechanical factors. The expected top speed on a level sandy surface is 4 mph instead of the desired 7 mph. This is due to a lack of necessary power at the wheels. The lack of power resulted from dimension considerations that allowed only an eight horsepower engine and also from mechanical inefficiencies of the hydraulic system. However, the vehicle will be able to climb a 30 percent grade, surpass a one meter high object and one meter wide crevice. The wheel assemblies will be able to support the entire weight of the vehicle on two wheels. The wheels will also provide adequate suspension for the vehicle and sufficient traction for lunar-type surfaces.

  7. Mechanical Engineering of the Linac for the Spallation Neutron Source

    International Nuclear Information System (INIS)

    Bultman, N.K.; Chen, Z.; Collier, M.; Erickson, J.L.; Guthrie, A.; Hunter, W.T.; Ilg, T.; Meyer, R.K.; Snodgrass, N.L.

    1999-01-01

    The linac for the Spallation Neutron Source (SNS) Project will accelerate an average current of 1 mA of H - ions from 20 MeV to 1GeV for injection into an accumulator ring. The linac will be an intense source of H - ions and as such requires advanced design techniques to meet project technical goals as well as to minimize costs. The DTL, CCDTL and CCL are 466m long and operate at 805 MHz with a maximum H - input current of 28 mA and 7% rf duty factor. The Drift Tube Linac is a copper-plated steel structure using permanent magnetic quadrupoles. The Coupled-Cavity portions are brazed copper structures and use electromagnetic quads. RF losses in the copper are 80 MW, with total rf power supplied by 52 klystrons. Additionally, the linac is to be upgraded to the 2- and 4-MW beam power levels with no increase in duty factor. The authors give an overview of the linac mechanical engineering effort and discuss the special challenges and status of the effort

  8. Mechanical engineering prospects at the end of the twentieth century

    International Nuclear Information System (INIS)

    Garcia Rodriguez, A.

    1993-01-01

    The future of Mechanical Engineering in Spain appears to be very bright indeed. This conclusion has been derived from an analysis of its evolution in the last 20 years, a period which has seen the development of excellent working universities, research organizations and centres, and in industry. The initial delay in Spain's industrialization process, as compared to other European countries, has led to the situation where we do not have multinational companies which are purely Spanish-owned in these areas. Nevertheless, a process of globalization of the industry is clearly under way, not only in Europe, under the aegis of the EC, but also all over the world. This implies that in this new context it will be possible to access, from Spain itself, posts of growing responsibility in large post-multinational companies, and also to work in areas I have defined as more noble. The possibility of these companies implementing activities of major interest in Spain will depend on factors such as existing infrastructure, qualification of personnel and the surrounding life style. The qualification of personnel relies on basic training and promotion of research activities; therefore, these aspects will require special attention. (author)

  9. A Study of Competence in Mathematics and Mechanics in an Engineering Curriculum

    Science.gov (United States)

    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…

  10. Modeling the impact of scaffold architecture and mechanical loading on collagen turnover in engineered cardiovascular tissues

    NARCIS (Netherlands)

    Argento, G.; de Jonge, N.; Söntjens, S.H.M.; Oomens, C.W.J.; Bouten, C.V.C.; Baaijens, F.P.T.

    2015-01-01

    The anisotropic collagen architecture of an engineered cardiovascular tissue has a major impact on its in vivo mechanical performance. This evolving collagen architecture is determined by initial scaffold microstructure and mechanical loading. Here, we developed and validated a theoretical and

  11. NASA GSFC Mechanical Engineering Latest Inputs for Verification Standards (GEVS) Updates

    Science.gov (United States)

    Kaufman, Daniel

    2003-01-01

    This viewgraph presentation provides information on quality control standards in mechanical engineering. The presentation addresses safety, structural loads, nonmetallic composite structural elements, bonded structural joints, externally induced shock, random vibration, acoustic tests, and mechanical function.

  12. A dual flow bioreactor with controlled mechanical stimulation for cartilage tissue engineering

    NARCIS (Netherlands)

    Spitters, Tim; Leijten, Jeroen Christianus Hermanus; Deus, F.D.; Costa, I.B.F.; van Apeldoorn, Aart A.; van Blitterswijk, Clemens; Karperien, Hermanus Bernardus Johannes

    2013-01-01

    In cartilage tissue engineering bioreactors can create a controlled environment to study chondrocyte behavior under mechanical stimulation or produce chondrogenic grafts of clinically relevant size. Here we present a novel bioreactor, which combines mechanical stimulation with a two compartment

  13. Review on patents for mechanical stimulation of articular cartilage tissue engineering

    NARCIS (Netherlands)

    Donkelaar, van C.C.; Schulz, R.M.

    2008-01-01

    To repair articular cartilage defects in osteoarthritic patients with three-dimensional tissue engineered chondrocyte grafts, requires the formation of new cartilage with sufficient mechanical properties. The premise is that mechanical stimulation during the culturing process is necessary to reach

  14. Proceedings of the COBEM 99: 15. Brazilian congress on mechanical engineering. Engineering committed to quality of life. Abstracts

    International Nuclear Information System (INIS)

    1999-01-01

    Theoretical and experimental papers are presented approaching the following area and subjects: petroleum industry, equipment and products, gas and wind turbines, hydroelectric power plants and equipment, environment, mechanical engineering, computerized analysis, fluid flow, thermal machines, fluid flow and mechanics, porous media, nuclear energy, refrigeration, bioengineering, energy sources, consumption and conservation

  15. Embarked diagnosis applied to a mechanical system "diesel engine ...

    African Journals Online (AJOL)

    The implementation of OBD (on-board diagnostic) systems for diesel engines has become an unavoidable necessity. From the models described in the literature, the latest generation diesel engine models as well as defects affecting it were established. A board diagnostic system based on the use of fuzzy pattern ...

  16. Development of a robust and compact kerosene–diesel reaction mechanism for diesel engines

    International Nuclear Information System (INIS)

    Tay, Kun Lin; Yang, Wenming; Mohan, Balaji; An, Hui; Zhou, Dezhi; Yu, Wenbin

    2016-01-01

    Highlights: • An approach is used to develop a robust kerosene–diesel reaction mechanism. • Ignition delay of the kerosene sub-mechanism is well validated with experiments. • The kerosene sub-mechanism reproduces the flame lift-off lengths of Jet-A reasonably well. • The kerosene sub-mechanism performs reasonably well under engine conditions. - Abstract: The use of kerosene fuels in internal combustion engines is getting more widespread. The North Atlantic Treaty Organization military is pushing for the use of a single fuel on the battlefield in order to reduce logistical issues. Moreover, in some countries, fuel adulteration is a serious matter where kerosene is blended with diesel and used in diesel engines. So far, most investigations done regarding the use of kerosene fuels in diesel engines are experimental and there is negligible simulation work done in this area possibly because of the lack of a robust and compact kerosene reaction mechanism. This work focuses on the development of a small but reliable kerosene–diesel reaction mechanism, suitable to be used for diesel engine simulations. The new kerosene–diesel reaction mechanism consists only of 48 species and 152 reactions. Furthermore, the kerosene sub-mechanism in this new mechanism is well validated for its ignition delay times and has proven to replicate kerosene combustion well in a constant volume combustion chamber and an optical engine. Overall, this new kerosene–diesel reaction mechanism is proven to be robust and practical for diesel engine simulations.

  17. 49 CFR 173.220 - Internal combustion engines, self-propelled vehicles, mechanical equipment containing internal...

    Science.gov (United States)

    2010-10-01

    ... and vehicles with certain electronic equipment when transported by aircraft or vessel. When an... vehicles, mechanical equipment containing internal combustion engines, and battery powered vehicles or... Than Class 1 and Class 7 § 173.220 Internal combustion engines, self-propelled vehicles, mechanical...

  18. Reducing barriers to energy efficiency in the German mechanical engineering sector. Executive summary

    Energy Technology Data Exchange (ETDEWEB)

    Schleich, J.; Boede, U.

    2000-12-01

    This report describes the empirical research into barriers to energy efficiency in the German mechanical engineering (ME) sector. It is one of nine such reports in the BARRIERS project. The report contains description and analysis of four case studies of energy management in German companies in the ME sector. The results are analysed using the theoretical framework developed for the BARRIERS project. The report also provides brief recommendations on how these barriers to the rational use of energy (RUE) may be overcome and how energy efficiency within the ME sector may be improved. The results of the study for the ME sector in Germany are summarised in this executive summary under the following headings: - Characterising the mechanical engineering sector; - Case studies of energy management in the German mechanical engineering sector; - Evidence of barriers in the German mechanical engineering sector; - The role of energy service companies in the mechanical engineering sector; - Policy implications. (orig.)

  19. Reducing barriers to energy efficiency in the German mechanical engineering sector. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Schleich, J.; Boede, U.

    2000-12-01

    This report describes the empirical research into barriers to energy efficiency in the German mechanical engineering (ME) sector. It is one of nine such reports in the BARRIERS project. The report contains description and analysis of four case studies of energy management in German companies in the ME sector. The results are analysed using the theoretical framework developed for the BARRIERS project. The report also provides brief recommendations on how these barriers to the rational use of energy (RUE) may be overcome and how energy efficiency within the ME sector may be improved. The results of the study for the ME sector in Germany are summarised in this executive summary under the following headings: - Characterising the mechanical engineering sector; - Case studies of energy management in the German mechanical engineering sector; - Evidence of barriers in the German mechanical engineering sector; - The role of energy service companies in the mechanical engineering sector; - Policy implications. (orig.)

  20. Bluff evolution along coastal drumlins: Boston Harbor Islands, Massachusetts

    Science.gov (United States)

    Himmelstoss, E.A.; FitzGerald, D.M.; Rosen, P.S.; Allen, J.R.

    2006-01-01

    A series of partially drowned drumlins forms the backbone of the inner islands within Boston Harbor. The shoreline of these rounded glacial deposits is composed of actively retreating bluffs formed by continual wave attack. Comparisons of bluffs reveal variability in their height and lateral extent, as well as in the dominant mechanism causing their retreat. Two processes are responsible for bluff erosion and yield distinct bluff morphologies: (1) wave attack undercuts the bluff and causes episodic slumping, yielding planar bluff slopes, and (2) subaerial processes such as rainfall create irregular slopes characterized by rills and gullies. We propose a model of drumlin bluff evolution that is based on processes of erosion and physical characteristics such as bluff height, slope morphology, and the orientation of the bluff with respect to the long axis of the drumlin and its topographic crest. The four phases of drumlin bluff evolution consist of (1) initial formation of bluff, with retreat dominated by wave notching and slumping processes; (2) rill and gully development as bluff heights exceed 10 m and slumped sediment at bluff base inhibits wave attack; (3) return of wave notching and slumping as bluff heights decrease; and (4) final development of boulder retreat lag as last remnants of drumlin are eroded by wave action. These phases capture the important physical processes of drumlin evolution in Boston Harbor and could apply to other eroding coastal drumlin deposits.

  1. Cohort profile: the Boston Area Community Health (BACH) survey.

    Science.gov (United States)

    Piccolo, Rebecca S; Araujo, Andre B; Pearce, Neil; McKinlay, John B

    2014-02-01

    The Boston Area Community Health (BACH) Survey is a community-based, random sample, epidemiologic cohort of n = 5502 Boston (MA) residents. The baseline BACH Survey (2002-05) was designed to explore the mechanisms conferring increased health risks on minority populations with a particular focus on urologic signs/symptoms and type 2 diabetes. To this end, the cohort was designed to include adequate numbers of US racial/ethnic minorities (Black, Hispanic, White), both men and women, across a broad age of distribution. Follow-up surveys were conducted ∼5 (BACH II, 2008) and 7 (BACH III, 2010) years later, which allows for both within- and between-person comparisons over time. The BACH Survey's measures were designed to cover the following seven broad categories: socio-demographics, health care access/utilization, lifestyles, psychosocial factors, health status, physical measures and biochemical parameters. The breadth of measures has allowed BACH researchers to identify disparities and quantify contributions to social disparities in a number of health conditions including urologic conditions (e.g. nocturia, lower urinary tract symptoms, prostatitis), type 2 diabetes, obesity, bone mineral content and density, and physical function. BACH I data are available through the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) Central Repositories (www.niddkrepository.org). Further inquiries can be made through the New England Research Institutes Inc. website (www.neriscience.com/epidemiology).

  2. Mechanical Properties Experimental Study of Engineering Vehicle Refurbished Tire

    Science.gov (United States)

    Qiang, Wang; Xiaojie, Qi; Zhao, Yang; Yunlong, Wang; Guotian, Wang; Degang, Lv

    2018-05-01

    The vehicle refurbished tire test system was constructed, got load-deformation, load-stiffness, and load-compression ratio property laws of engineering vehicle refurbished tire under the working condition of static state and ground contact, and built radial direction loading deformation mathematics model of 26.5R25 engineering vehicle refurbished tire. The test results show that radial-direction and side-direction deformation value is a little less than that of the new tire. The radial-direction stiffness and compression ratio of engineering vehicle refurbished tire were greatly influenced by radial-direction load and air inflation pressure. When load was certain, radial-direction stiffness would increase with air inflation pressure increasing. When air inflation pressure was certain, compression ratio of engineering vehicle refurbished tire would enlarge with radial-direction load increasing, which was a little less than that of the new and the same type tire. Aging degree of old car-case would exert a great influence on deformation property of engineering vehicle refurbished tire, thus engineering vehicle refurbished tires are suitable to the working condition of low tire pressure and less load.

  3. Comparative study on the mechanical mechanism of confined concrete supporting arches in underground engineering.

    Science.gov (United States)

    Lv, Zhijin; Qin, Qian; Jiang, Bei; Luan, Yingcheng; Yu, Hengchang

    2018-01-01

    In order to solve the supporting problem in underground engineering with high stress, square steel confined concrete (SQCC) supporting method is adopted to enhance the control on surrounding rocks, and the control effect is remarkable. The commonly used cross section shapes of confined concrete arch are square and circular. At present, designers have no consensus on which kind is more proper. To search for the answer, this paper makes an analysis on the mechanical properties of the two shapes of the cross-sections. A full-scale indoor comparative test was carried out on the commonly used straight-wall semi-circular SQCC arch and circular steel confined concrete arch (CCC arch). This test is based on self-developed full-scale test system for confined concrete arch. Our research, combining with the numerical analysis, shows: (1) SQCC arch is consistent with CCC arch in the deformation and failure mode. The largest damages parts are at the legs of both of them. (2) The SQCC arch's bearing capability is 1286.9 kN, and the CCC arch's ultimate bearing capability is 1072.4kN. Thus, the SQCC arch's bearing capability is 1.2 times that of the CCC arch. (3) The arches are subjected to combined compression and bending, bending moment is the main reason for the arch failure. The section moment of inertia of SQCC arch is 1.26 times of that of CCC arch, and the former is better than the latter in bending performance. The ultimate bearing capacity is positively correlated with the size of the moment of inertia. Based on the above research, the engineering suggestions are as follows: (1) To improve the bearing capacity of the arch, the cross-sectional shape of the chamber should be optimized and the arch bearing mode changed accordingly. (2) The key damaged positions, such as the arch leg, should be reinforced, optimizing the state of force on the arch. SQCC arches should be used for supporting in underground engineering, which is under stronger influence of the bending moment and

  4. Study of nozzle deposit formation mechanism for direct injection gasoline engines; Chokufun gasoline engine yo nozzle no deposit seisei kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Kinoshita, M; Saito, A [Toyota Central Research and Development Labs., Inc., Aichi (Japan); Matsushita, S [Toyota Motor Corp., Aichi (Japan); Shibata, H [Nippon Soken, Inc., Tokyo (Japan); Niwa, Y [Denso Corp., Aichi (Japan)

    1997-10-01

    Nozzles in fuel injectors for direct injection gasoline engines are exposed to high temperature combustion gases and soot. In such a rigorous environment, it is a fear that fuel flow rate changes in injectors by deposit formation on nozzles. Fundamental factors of nozzle deposit formation were investigated through injector bench tests and engine dynamometer tests. Deposit formation processes were observed by SEM through engine dynamometer tests. The investigation results reveal nozzle deposit formation mechanism and how to suppress the deposit. 4 refs., 8 figs., 3 tabs.

  5. Mechanical Engineering Department technical abstracts for the period January-June 1985

    International Nuclear Information System (INIS)

    Woo, H.H.

    1986-01-01

    This document contains the abstracts from 116 reports produced by the Mechanical Engineering Department of the Lawrence Livermore National Laboratory during the period January - June, 1985. The Mechanical Engineering Department is reponsible for the design, analysis, fabrication, testing, and field installation of all mechanical components and systems required by Defence Systems, Lasers, Magnetic Fusion Energy, Physics, and Biomedical and Environmental Research. Similar support is provided to the Chemistry and Computation Departments. Keyword, author, and report-number indices are included

  6. Thermal and Mechanical Design Aspects of the LIFE Engine

    Energy Technology Data Exchange (ETDEWEB)

    Abbott, R P; Gerhard, M A; Latkowski, J F; Kramer, K J; Morris, K R; Peterson, P F; Seifried, J E

    2008-10-25

    The Laser Inertial confinement fusion - Fission Energy (LIFE) engine encompasses the components of a LIFE power plant responsible for converting the thermal energy of fusion and fission reactions into electricity. The design and integration of these components must satisfy a challenging set of requirements driven by nuclear, thermal, geometric, structural, and materials considerations. This paper details a self-consistent configuration for the LIFE engine along with the methods and technologies selected to meet these stringent requirements. Included is discussion of plant layout, coolant flow dynamics, fuel temperatures, expected structural stresses, power cycle efficiencies, and first wall survival threats. Further research and to understand and resolve outstanding issues is also outlined.

  7. Mechanics of oriented electrospun nanofibrous scaffolds for annulus fibrosus tissue engineering.

    Science.gov (United States)

    Nerurkar, Nandan L; Elliott, Dawn M; Mauck, Robert L

    2007-08-01

    Engineering a functional replacement for the annulus fibrosus (AF) of the intervertebral disc is contingent upon recapitulation of AF structure, composition, and mechanical properties. In this study, we propose a new paradigm for AF tissue engineering that focuses on the reconstitution of anatomic fiber architecture and uses constitutive modeling to evaluate construct function. A modified electrospinning technique was utilized to generate aligned nanofibrous polymer scaffolds for engineering the basic functional unit of the AF, a single lamella. Scaffolds were tested in uniaxial tension at multiple fiber orientations, demonstrating a nonlinear dependence of modulus on fiber angle that mimicked the nonlinearity and anisotropy of native AF. A homogenization model previously applied to native AF successfully described scaffold mechanical response, and parametric studies demonstrated that nonfibrillar matrix, along with fiber connectivity, are key contributors to tensile mechanics for engineered AF. We demonstrated that AF cells orient themselves along the aligned scaffolds and deposit matrix that contributes to construct mechanics under loading conditions relevant to the in vivo environment. The homogenization model was applied to cell-seeded constructs and provided quantitative measures for the evolution of matrix and interfibrillar interactions. Finally, the model demonstrated that at fiber angles of the AF (28 degrees -44 degrees ), engineered material behaved much like native tissue, suggesting that engineered constructs replicate the physiologic behavior of the single AF lamella. Constitutive modeling provides a powerful tool for analysis of engineered AF neo-tissue and native AF tissue alike, highlighting key mechanical design criteria for functional AF tissue engineering.

  8. Mechanical cues in orofacial tissue engineering and regenerative medicine

    NARCIS (Netherlands)

    Brouwer, K.M.; Lundvig, D.M.S.; Middelkoop, E.; Wagener, F.A.D.T.; Von den Hoff, J.W.

    2015-01-01

    Cleft lip and palate patients suffer from functional, aesthetical, and psychosocial problems due to suboptimal regeneration of skin, mucosa, and skeletal muscle after restorative cleft surgery. The field of tissue engineering and regenerative medicine (TE/RM) aims to restore the normal physiology of

  9. comparison of elastic-plastic FE method and engineering method for RPV fracture mechanics analysis

    International Nuclear Information System (INIS)

    Sun Yingxue; Zheng Bin; Zhang Fenggang

    2009-01-01

    This paper described the FE analysis of elastic-plastic fracture mechanics for a crack in RPV belt line using ABAQUS code. It calculated and evaluated the stress intensity factor and J integral of crack under PTS transients. The result is also compared with that by engineering analysis method. It shows that the results using engineering analysis method is a little larger than the results using FE analysis of 3D elastic-plastic fracture mechanics, thus the engineering analysis method is conservative than the elastic-plastic fracture mechanics method. (authors)

  10. A Comparison of the mechanical engineering and safety engineering student’s ICT attitudes at the Obuda University

    Directory of Open Access Journals (Sweden)

    Kiss Gabor

    2016-01-01

    Full Text Available Communication and technology are critical to education. However, using technology in education is not an easy task as communication barriers emerge. The aim of this research is to analyze the ICT attitudes from different faculties at the Obuda University that is between the mechanical engineering students and safety engineering students from the Donát Bánki Mechanical Safety Engineer Faculty. The students from these two groups will use different ICT tool at work after their graduation; the mechanical engineering students will work mostly with designer ICT tools, the safety engineering students will use security systems. It would be important to know whether instructors, when using ICT, have to follow different teaching methods and approaches in these two different groups or not. We measured the ICT attitude with a tool consisting of 23 items (Likert scaled. We worked with 361 students. The data analysis was performed with SPSS software using descriptive statistics and Mann-Whitney test. The results show both groups having the same positive ICT attitude however with one difference.

  11. Automatic compression adjusting mechanism for internal combustion engines

    Science.gov (United States)

    Akkerman, J. W. (Inventor)

    1983-01-01

    Means for controlling the compression pressure in an internal combustion engine having one or more cylinders and subject to widely varying power output requirements are provided. Received between each crank pin and connecting rod is an eccentric sleeve selectively capable of rotation about the crank pin and/or inside the rod and for latching with the rod to vary the effective length of the connecting rod and thereby the clearance volume of the engine. The eccentric normally rotates inside the connecting rod during the exhaust and intake strokes but a latching pawl carried by the eccentric is movable radially outwardly to latch the rod and eccentric together during the compression and power strokes. A control valve responds to intake manifold pressure to time the supply of hydraulic fluid to move the latch-pawl outwardly, varying the effective rod length to maintain a substantially optimum firing chamber pressure at all intake manifold pressures.

  12. Dynamic Mechanical and Nanofibrous Topological Combinatory Cues Designed for Periodontal Ligament Engineering.

    Science.gov (United States)

    Kim, Joong-Hyun; Kang, Min Sil; Eltohamy, Mohamed; Kim, Tae-Hyun; Kim, Hae-Won

    2016-01-01

    Complete reconstruction of damaged periodontal pockets, particularly regeneration of periodontal ligament (PDL) has been a significant challenge in dentistry. Tissue engineering approach utilizing PDL stem cells and scaffolding matrices offers great opportunity to this, and applying physical and mechanical cues mimicking native tissue conditions are of special importance. Here we approach to regenerate periodontal tissues by engineering PDL cells supported on a nanofibrous scaffold under a mechanical-stressed condition. PDL stem cells isolated from rats were seeded on an electrospun polycaprolactone/gelatin directionally-oriented nanofiber membrane and dynamic mechanical stress was applied to the cell/nanofiber construct, providing nanotopological and mechanical combined cues. Cells recognized the nanofiber orientation, aligning in parallel, and the mechanical stress increased the cell alignment. Importantly, the cells cultured on the oriented nanofiber combined with the mechanical stress produced significantly stimulated PDL specific markers, including periostin and tenascin with simultaneous down-regulation of osteogenesis, demonstrating the roles of topological and mechanical cues in altering phenotypic change in PDL cells. Tissue compatibility of the tissue-engineered constructs was confirmed in rat subcutaneous sites. Furthermore, in vivo regeneration of PDL and alveolar bone tissues was examined under the rat premaxillary periodontal defect models. The cell/nanofiber constructs engineered under mechanical stress showed sound integration into tissue defects and the regenerated bone volume and area were significantly improved. This study provides an effective tissue engineering approach for periodontal regeneration-culturing PDL stem cells with combinatory cues of oriented nanotopology and dynamic mechanical stretch.

  13. Use of Concept Maps as an Assessment Tool in Mechanical Engineering Education

    Science.gov (United States)

    Tembe, B. L.; Kamble, S. K.

    2013-01-01

    The purpose of this study to investigate, how third year mechanical engineering students are able to use their knowledge of concept maps in their study of the topic of "Introduction to the Internal Combustion Engines (IICE)". 41 students participated in this study. Firstly, the students were taught about concept maps and then asked to…

  14. Curriculum Development Based on the Big Picture Assessment of the Mechanical Engineering Program

    Science.gov (United States)

    Sabri, Mohd Anas Mohd; Khamis, Nor Kamaliana; Tahir, Mohd Faizal Mat; Wahid, Zaliha; Kamal, Ahmad; Ihsan, Ariffin Mohd; Sulong, Abu Bakar; Abdullah, Shahrum

    2013-01-01

    One of the major concerns of the Engineering Accreditation Council (EAC) is the need for an effective monitoring and evaluation of program outcome domains that can be associated with courses taught under the Mechanical Engineering program. However, an effective monitoring method that can determine the results of each program outcome using Bloom's…

  15. Profiles of Automotive Suppliers Industries--Engineered Mechanical Components and Systems : Volume II, Appendices.

    Science.gov (United States)

    1981-09-01

    The profile describes and analyzes that segment of the automotive supplier industry which provides engineered mechanical components/assemblies/systems to the prime auto manufacturers. It presents an overview of the role and structure of this industry...

  16. Profiles of Automotive Suppliers Industries--Engineered Mechanical Components and Systems : Volume I, Text.

    Science.gov (United States)

    1981-09-01

    This profile describes and analyzes that segment of the automotive supplier industry which provides engineered mechanical components/assemblies/systems to the prime auto manufacturers. It presents an overview of the role and structure of this industr...

  17. Prospect of mechanical engineering. Report from MIT; Kikai kogaku no atarashii tenkai. MIT kara no hokoku

    Energy Technology Data Exchange (ETDEWEB)

    Asada, H [Massachusetts Inst. of Technology, Cambridge, MA (United States)

    1996-01-05

    The author of this article is a professor of Department of Mechanical Engineering of Massachusetts Institute of Technology (MIT) and the director general of Laboratory for Information Systems and Technology of the institute. At Department of Mechanical Engineering of Engineering Faculty of world-famous MIT, Laboratory for Information Systems and Technology was established in 1994 and in the same year, the curricula of the department were greatly revised after 30 years for its enforcement from the new semester starting from September, 1995. These two occasions are suggestive for guessing the future of mechanical engineering, hence its aim and meaning are introduced. Department of Mechanical Engineering aims to bring up system integrators who can consolidate systems based on wide-ranged knowledge, and its basic subjects are divided into 4 subjects namely dynamics and control, heat and fluid, system engineering and control, and design and production, and it has been decided that each of them is taught in equal weight and in parallel. Also as a new study field in the above Department of Mechanical Engineering, nanotechnology and artificial intelligence, and high-technological aircraft and networks are shown as examples.

  18. Computational Quantum Mechanics for Materials Engineers The EMTO Method and Applications

    CERN Document Server

    Vitos, L

    2007-01-01

    Traditionally, new materials have been developed by empirically correlating their chemical composition, and the manufacturing processes used to form them, with their properties. Until recently, metallurgists have not used quantum theory for practical purposes. However, the development of modern density functional methods means that today, computational quantum mechanics can help engineers to identify and develop novel materials. Computational Quantum Mechanics for Materials Engineers describes new approaches to the modelling of disordered alloys that combine the most efficient quantum-level th

  19. Particular mechanism for continuously varying the compression ratio for an internal combustion engine

    Science.gov (United States)

    Raţiu, S.; Cătălinoiu, R.; Alexa, V.; Miklos, I.; Cioată, V.

    2018-01-01

    Variable compression ratio (VCR) is a technology to adjust the compression ratio of an internal combustion engine while the engine is in operation. The paper proposes the presentation of a particular mechanism allowing the position of the top dead centre to be changed, while the position of the bottom dead centre remains fixed. The kinematics of the mechanism is studied and its trajectories are graphically represented for different positions of operation.

  20. A Model for Implementing Practical Design in the Education of Mechanical Engineers

    DEFF Research Database (Denmark)

    Hansen, Michael Rygaard; Mouritsen, Ole Ø.; Andersen, Torben Ole

    2006-01-01

    In this paper the PBL model used at Aalborg University in the mechanical engineering is shortly presented. A specific semester with a both theoretical and practical content that allow the students to is presented in detail. It is then used as a reference project for a subsequent discussion on three...... potential concerns with respect to the continued succes of problem and project based learning in mechanical and mechatronics engineering namely: individual assessment, bologna (student exchange) model and research based teaching....

  1. Development of a mechanical maintenance training simulator in OpenSimulator for F-16 aircraft engines

    OpenAIRE

    Pinheiro, André; Fernandes, Paulo; Maia, Ana; Cruz, Gonçalo; Pedrosa, Daniela; Fonseca, Benjamim; Paredes, Hugo; Martins, Paulo; Morgado, Leonel; Rafael, Jorge

    2014-01-01

    Mechanical maintenance of F-16 engines is carried out as a team effort involving 3–4 skilled engine technicians, but the details of its procedures and requisites change constantly, to improve safety, optimize resources, and respond to knowledge learned from field outcomes. This provides a challenge for development of training simulators, since simulated actions risk becoming obsolete rapidly and require costly reimplementation. This paper presents the development of a 3D mechanical maintenanc...

  2. Mechanical testing of hydrogels in cartilage tissue engineering: beyond the compressive modulus.

    Science.gov (United States)

    Xiao, Yinghua; Friis, Elizabeth A; Gehrke, Stevin H; Detamore, Michael S

    2013-10-01

    Injuries to articular cartilage result in significant pain to patients and high medical costs. Unfortunately, cartilage repair strategies have been notoriously unreliable and/or complex. Biomaterial-based tissue-engineering strategies offer great promise, including the use of hydrogels to regenerate articular cartilage. Mechanical integrity is arguably the most important functional outcome of engineered cartilage, although mechanical testing of hydrogel-based constructs to date has focused primarily on deformation rather than failure properties. In addition to deformation testing, as the field of cartilage tissue engineering matures, this community will benefit from the addition of mechanical failure testing to outcome analyses, given the crucial clinical importance of the success of engineered constructs. However, there is a tremendous disparity in the methods used to evaluate mechanical failure of hydrogels and articular cartilage. In an effort to bridge the gap in mechanical testing methods of articular cartilage and hydrogels in cartilage regeneration, this review classifies the different toughness measurements for each. The urgency for identifying the common ground between these two disparate fields is high, as mechanical failure is ready to stand alongside stiffness as a functional design requirement. In comparing toughness measurement methods between hydrogels and cartilage, we recommend that the best option for evaluating mechanical failure of hydrogel-based constructs for cartilage tissue engineering may be tensile testing based on the single edge notch test, in part because specimen preparation is more straightforward and a related American Society for Testing and Materials (ASTM) standard can be adopted in a fracture mechanics context.

  3. Analysis of engineering cycles thermodynamics and fluid mechanics series

    CERN Document Server

    Haywood, R W

    1980-01-01

    Analysis of Engineering Cycles, Third Edition, deals principally with an analysis of the overall performance, under design conditions, of work-producing power plants and work-absorbing refrigerating and gas-liquefaction plants, most of which are either cyclic or closely related thereto. The book is organized into two parts, dealing first with simple power and refrigerating plants and then moving on to more complex plants. The principal modifications in this Third Edition arise from the updating and expansion of material on nuclear plants and on combined and binary plants. In view of increased

  4. MECHANICAL ENGINEERING CURRICULUM AT DTU AND THE APPLICATION OF CDIO IN FIRST YEAR COURSES

    DEFF Research Database (Denmark)

    Houbak, Niels; Klit, Peder

    2005-01-01

    philosophy. This course in particular but also the design of the study plan will be described in this paper as will an ongoing effort on evaluating the current curriculum with improvements in mind. A part of this evaluation of the curriculum will involve an analysis of first year courses among some...... of Manufacturing Engineering and Management and the Department of Mechanical Engineering deliver the technical courses for the Bachelor education (called Production and Engineering Design, P&E). In cooperation the two departments gives an introductory ‘Engineering Work’ course with much emphasis on the CDIO...

  5. Engineering Mathematics I : Electromagnetics, Fluid Mechanics, Material Physics and Financial Engineering

    CERN Document Server

    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 ...

  6. Design Learning of Teaching Factory in Mechanical Engineering

    Science.gov (United States)

    Putra, R. C.; Kusumah, I. H.; Komaro, M.; Rahayu, Y.; Asfiyanur, E. P.

    2018-02-01

    The industrial world that is the target of the process and learning outcomes of vocational high school (SMK) has its own character and nuance. Therefore, vocational education institutions in the learning process should be able to make the appropriate learning approach and in accordance with the industrial world. One approach to learning that is based on production and learning in the world of work is by industry-based learning or known as Teaching Factory, where in this model apply learning that involves direct students in goods or service activities are expected to have the quality so it is worth selling and accepted by consumers. The method used is descriptive approach. The purpose of this research is to get the design of the teaching factory based on the competency requirements of the graduates of the spouse industry, especially in the engineering department. The results of this study is expected to be one of the choice of model factory teaching in the field of machinery engineering in accordance with the products and competencies of the graduates that the industry needs.

  7. Comparison of different chemical kinetic mechanisms of methane combustion in an internal combustion engine configuration

    OpenAIRE

    Ennetta Ridha; Hamdi Mohamed; Said Rachid

    2008-01-01

    Three chemical kinetic mechanisms of methane combustion were tested and compared using the internal combustion engine model of Chemkin 4.02 [1]: one-step global reaction mechanism, four-step mechanism, and the standard detailed scheme GRIMECH 3.0. This study shows good concordances, especially between the four-step and the detailed mechanisms in the prediction of temperature and main species profiles. But reduced schemes were incapables to predict pollutant emissions in an internal combustion...

  8. The International Congress of Mechanical Engineering and Agricultural Sciences – CIIMCA 2013

    International Nuclear Information System (INIS)

    Remolina-Millán, Aduljay; Hernández-Arroyo, Emil

    2014-01-01

    The organizing committee of The International Congress of Mechanical Engineering and Agricultural Sciences – CIIMCA 2013 – are pleased to present CIIMCA-2013: the first international conference focused on subjects of materials science, mechanical engineering and renewable energy organized by Mechanical Engineering Faculty of the ''Universidad Pontificia Bolivariana'' in Bucaramanga, Colombia. This conference aims to be a place to produce discussions on whole topics of the congress, between the scientists of Colombia and the world. We strongly believe that knowledge is fundamental to the development of our countries. For that reason this multidisciplinary conference is looking forward to integrate engineering, agricultural science and nanoscience and nanotechnology to produce a synergy of this area of knowledge and to achieve scientific and technological developments. Agriculture is a very important topic for our conference; in Colombia, agricultural science needs more attention from the scientific community and the government. In the Faculty of Mechanical Engineering we are beginning to work on these issues to produce knowledge and improve the conditions in our country. The CIIMCA conference is a great opportunity to create interpersonal relationships and networks between scientists around the world. The interaction between scientists is very important in the process of the construction of knowledge. The general chairman encourages and invites you to make friends, relationships and participate strongly in the symposia and all program activities. PhD Aduljay Remolina-Millán Principal Chairman, International Mechanical Engineering and Agricultural Sciences Congress – CIIMCA Msc Emil Hernández-Arroyo Principal Chairman, International Mechanical Engineering and Agricultural Sciences Congress – CIIMCA Conferencephotograph Conferencephotograph 'Universidad Pontificia Bolivariana seccional Bucaramanga' host of the first

  9. Investigations of leakage mechanisms and its influences on a micro swing engine considering rarefaction effects

    International Nuclear Information System (INIS)

    Zhou, Xiong; Zhang, Zhenyu; Kong, Wenjun; Du, Ning

    2016-01-01

    Highlights: • Mechanisms of the leakage flow in different flow regimes have been studied. • The leakage flow regime and patterns in the micro swing engine are presented. • Slip on the walls has a larger effect on leakage flow with decreasing the gap. • Rarefaction effects on the engine performance have been investigated. - Abstract: Considering rarefaction effects, this paper investigated mechanisms of the clearance leakage and its influences on a micro swing engine for the micro power generation by employing three different flow models named as discrete velocity direction (DVD) model, Navier-Stokes equations with slip boundary conditions (NS-slip) and no-slip boundary conditions (NS-no slip). Using the DVD model, this paper firstly studied leakage mechanisms of a micro Couette-Poisueille flow. Factors which control the leakage in different regimes were obtained. Furthermore, the system-level predictions of the clearance leakage in the micro swing engine have been conducted by solving the Navier-Stokes equations. The leakage flow regime, patterns and characteristics were presented. Results by NS-slip and NS-no slip were compared to study the rarefaction effects. Finally, investigations of the engine size and the gap height on the engine performance have been conducted. The significance of the leakage in different engine size regimes was presented, and the results show that rarefaction effects affect the indicated thermal efficiency greatly with the decrease of the engine size scale.

  10. A blended learning approach to teach fluid mechanics in engineering

    Science.gov (United States)

    Rahman, Ataur

    2017-05-01

    This paper presents a case study on the teaching and learning of fluid mechanics at the University of Western Sydney (UWS), Australia, by applying a blended learning approach (BLA). In the adopted BLA, various flexible learning materials have been made available to the students such as online recorded lectures, online recorded tutorials, hand written tutorial solutions, discussion board and online practice quizzes. The lecture and tutorial class times have been primarily utilised to discuss confusing topics and engage students with practical issues in applying the theories learnt in fluid mechanics. Based on the data of over 734 students over a 4-year period, it has been shown that a BLA has improved the learning experience of the fluid mechanics students in UWS. The overall percentage of student satisfaction in this subject has increased by 18% in the BLA case compared with the traditional one.

  11. Stirling engine power control and motion conversion mechanism

    Science.gov (United States)

    Marks, David T.

    1983-01-01

    A motion conversion device for converting between the reciprocating motion of the pistons in a Stirling engine and the rotating motion of its output shaft, and for changing the stroke and phase of the pistons, includes a lever pivoted at one end and having a cam follower at the other end. The piston rod engages the lever intermediate its ends and the cam follower engages a cam keyed to the output shaft. The lever pivot can be moved to change the length of the moment arm defined between the cam follower and the piston rod the change the piston stroke and force exerted on the cam, and the levers can be moved in opposite directions to change the phase between pistons.

  12. Mechanical properties of Composite Engineering Structures by Multivolume Micromechanical Modelling

    Directory of Open Access Journals (Sweden)

    B. Novotný

    2000-01-01

    Full Text Available Engineering structures often consist of elements having the character of a periodically repeated composite structure. A multivolume micromechanical model based on a representative cell division into r1 × r2 × r3 subcells with different elastic material properties has been used in this paper to derive macromechanical characteristics of the composite construction response to applied load and temperature changes. The multivolume method is based on ensuring the equilibrium of the considered volume on an average basis. In the same (average way, the continuity conditions of displacements and tractions at the interfaces between subcells and between neighboring representative elements are imposed, resulting in a homogenization procedure that eliminates the discrete nature of the composite model. The details of the method are shown for the case of a concrete block pavement. A parametric study is presented illustrating the influence of joint thickness, joint filling material properties and the quality of bonding between block and filler elements.

  13. Department of Mechanical Engineering, lISe, Bangalore 560 012

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 5; Issue 12. Founder of Modern Fluid Mechanics. Jaywant H Arakeri. Article-in-a-Box Volume 5 Issue 12 December 2000 pp 2-3. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/005/12/0002-0003 ...

  14. A Blended Learning Approach to Teach Fluid Mechanics in Engineering

    Science.gov (United States)

    Rahman, Ataur

    2017-01-01

    This paper presents a case study on the teaching and learning of fluid mechanics at the University of Western Sydney (UWS), Australia, by applying a blended learning approach (BLA). In the adopted BLA, various flexible learning materials have been made available to the students such as online recorded lectures, online recorded tutorials, hand…

  15. Matrix methods applied to engineering rigid body mechanics

    Science.gov (United States)

    Crouch, T.

    The purpose of this book is to present the solution of a range of rigorous body mechanics problems using a matrix formulation of vector algebra. Essential theory concerning kinematics and dynamics is formulated in terms of matrix algebra. The solution of kinematics and dynamics problems is discussed, taking into account the velocity and acceleration of a point moving in a circular path, the velocity and acceleration determination for a linkage, the angular velocity and angular acceleration of a roller in a taper-roller thrust race, Euler's theroem on the motion of rigid bodies, an automotive differential, a rotating epicyclic, the motion of a high speed rotor mounted in gimbals, and the vibration of a spinning projectile. Attention is given to the activity of a force, the work done by a conservative force, the work and potential in a conservative system, the equilibrium of a mechanism, bearing forces due to rotor misalignment, and the frequency of vibrations of a constrained rod.

  16. General Mechanical Repair. Minor Automotive Maintenance, Small Engine [Repair, and] Welding: Competency Test Package.

    Science.gov (United States)

    Hamlin, Larry

    This document contains the competency test package for three sections of a general mechanical repair course: minor automotive maintenance, small engine mechanics, and welding. Following a list of the common essential elements for trade and industrial education, competency tests for the three sections are provided. Each test includes unit name,…

  17. Dynamic model of Stirling engine crank mechanism with connected electric generator

    Directory of Open Access Journals (Sweden)

    Vlach R.

    2009-06-01

    Full Text Available This paper treats of a numerical dynamic model of Stirling engine crank mechanism. The model is included in the complex model of combined heat and power unit. The unit is composed of the Stirling engine and of attached three-phase synchronous generator. This generator should start the Stirling engine in motor mode as well. It is necessary to combine the crank shaft dynamic model and the complete thermal model of Stirling engine for simulations and analyses of engine run. Our aim is to create a dynamics model which takes into account the parameters of crankshaft, piston rods, pistons, and attached generator. For unit working, the electro-mechanical behaviour of generator is also important. That is why we experimentally verified the parameters of generator. The measured characteristics are used in a complex model of heat and power unit. Moreover, it is also possible to determine the Stirling engine torque by the help of these electro-mechanical characteristics. These values can be used e. g. for determination of optimal engine working point or for unit control.

  18. 77 FR 59551 - Safety Zone, Changes to Original Rule; Boston Harbor's Rock Removal Project, Boston Inner Harbor...

    Science.gov (United States)

    2012-09-28

    ... DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 165 [Docket No. USCG-2012-0767] RIN 1625-AA00 Safety Zone, Changes to Original Rule; Boston Harbor's Rock Removal Project, Boston Inner Harbor... original provisions of that temporary final rule, but adds two additional safety zones necessary for the...

  19. The Engineering Mechanism in Formation of Informational Basis of Analysis of Financial Sustainability of Enterprise

    Directory of Open Access Journals (Sweden)

    Chumak Oksana V.

    2017-12-01

    Full Text Available The article is aimed at substantiating the mechanism and instruments of financial and accountancy engineering with purpose of formation of information support of analysis of financial sustainability in the enterprise management system. The essence and preconditions of introduction of financial and accountancy engineering are disclosed. Expediency of application of the financial engineering mechanism at enterprise while analyzing financial sustainability has been substantiated. An analysis of methods of formation and use of derivative balance reports was carried out. Models of the conception of mechanisms and instruments of financial and accountancy engineering in analyzing the financial sustainability of enterprise have been suggested. A mega-accounts system in the working plan of the enterprise’s accounts has been recommended. Seven iterations have been provided, which constitute the basis of accounting-analytical support of the accountancy engineering. The information obtained on the basis of the financial and accountancy engineering mechanism allows to carry out real assessment of the enterprise’s financial sustainability.

  20. Selection of pipeline steels with an engineering fracture mechanical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Stenbacka, N [Swedish State Power Board, Vaellingby

    1985-01-01

    Selection of pipeline steels is discussed on the basis of two mutually independent failure mechanisms: elastic fracture and plastic collapse. The presentation is restricted to axial flaws. A formal analysis shows that brittle fracture in modern pipelines has no high priority in design, since steels used today have a high fracture toughness. Instead, a case of practical concern is tha plastic collapse mode, where failure is flow stress controlled. Conditions governing this design case are specified. In conjunction with this, criterions for material selection with regard to fracture toughness is presented.

  1. Corrosion problems of materials for mechanical, power and chemical engineering

    International Nuclear Information System (INIS)

    Bouska, P.; Cihal, V.; Malik, K.; Vyklicky, M.; Stefec, R.

    1988-01-01

    The proceedings contain 47 contributions, out of which 8 have been inputted in INIS. These are concerned with various corrosion problems of WWER primary circuit components and their testing. The factors affecting the corrosion resistance are analyzed, the simultaneous corrosion action of decontamination of steels is assessed, and the corrosion cracking of special steels is dealt with. The effects of deformation on the corrosion characteristics are examined for steel to be used in fast reactors. The corrosion potentials were measured for various steels. A testing facility for corrosion-mechanical tests is briefly described. (M.D.). 5 figs., 5 tabs., 25 refs

  2. Automatization and mechanization of welding in nuclear engineering

    Energy Technology Data Exchange (ETDEWEB)

    Shul' ma, I E; Kupin, N V

    1986-02-01

    The state of welding and cladding works, which constitute more than 12% of total labour content of NPP equipment production, is described. Special attention is paid to a considerable part of manual labour in the processes of thermal cutting and welding of joints inside the vessels. The necessity of perspective technology introduction is pointed out. It means, in particular, the introduction of technological complex robotics for automatic welding of pipes with tube plates in heat exchanger, the mechanization of cladding processes for sealing surfaces of locking equipment, facility equipment for the welding of steam generator vessels to bottoms by means of preliminary and concomitant heating devices.

  3. Graphite structure and its relation to mechanical engineering design

    International Nuclear Information System (INIS)

    Brocklehurst, J.E.; Kelly, B.T.

    1980-01-01

    The inhomogeneous nature of polycrystalline graphite requires property measurements to be made over dimensions large enough to average the local variations in the structure. This is particularly true for mechanical integrity, and experimental data are presented which illustrate the importance of the real aggregate structure of graphite and the difficulties of interpreting strength data from different tests. The classical statistical treatments do not hold generally, and the problem of defining a failure criterion for graphite is discussed. It is suggested that the stress conditions in graphite components might be classified in terms of the dimensions and stress gradients related to the characteristic flaw size of the material as determined experimentally. (author)

  4. Automatization and mechanization of welding in nuclear engineering

    International Nuclear Information System (INIS)

    Shul'ma, I.E.; Kupin, N.V.

    1986-01-01

    The state of welding and cladding works, which constitute more than 12% of total labour content of NPP equipment production, is described. Special attention is paid to a considerable part of manual labour in the processes of thermal cutting and welding of joints inside the vessels. The necessity of perspective technology introduction is pointed out. It means, in particular, the introduction of technological complex robotics for automatic welding of pipes with tube plates in heat exchanger, the mechanization of cladding processes for sealing surfaces of locking equipment, facility equipment for the welding of steam generator vessels to bottoms by means of preliminary and concomitant heating devices

  5. Effects of mechanical loading on human mesenchymal stem cells for cartilage tissue engineering.

    Science.gov (United States)

    Choi, Jane Ru; Yong, Kar Wey; Choi, Jean Yu

    2018-03-01

    Today, articular cartilage damage is a major health problem, affecting people of all ages. The existing conventional articular cartilage repair techniques, such as autologous chondrocyte implantation (ACI), microfracture, and mosaicplasty, have many shortcomings which negatively affect their clinical outcomes. Therefore, it is essential to develop an alternative and efficient articular repair technique that can address those shortcomings. Cartilage tissue engineering, which aims to create a tissue-engineered cartilage derived from human mesenchymal stem cells (MSCs), shows great promise for improving articular cartilage defect therapy. However, the use of tissue-engineered cartilage for the clinical therapy of articular cartilage defect still remains challenging. Despite the importance of mechanical loading to create a functional cartilage has been well demonstrated, the specific type of mechanical loading and its optimal loading regime is still under investigation. This review summarizes the most recent advances in the effects of mechanical loading on human MSCs. First, the existing conventional articular repair techniques and their shortcomings are highlighted. The important parameters for the evaluation of the tissue-engineered cartilage, including chondrogenic and hypertrophic differentiation of human MSCs are briefly discussed. The influence of mechanical loading on human MSCs is subsequently reviewed and the possible mechanotransduction signaling is highlighted. The development of non-hypertrophic chondrogenesis in response to the changing mechanical microenvironment will aid in the establishment of a tissue-engineered cartilage for efficient articular cartilage repair. © 2017 Wiley Periodicals, Inc.

  6. Assessment of the Use of AutoCAD in Mechanical Engineering Technical Drawing Education

    OpenAIRE

    Akyürek, Turgut

    2018-01-01

    AutoCAD is one of the widely used software tools in engineering education. In this study, ageneral assessment of AutoCAD for the usage in the mechanical engineering technical drawing educationis made. AutoCAD is assessed in terms of the fulfilment of the requirements defined for the main twotechnical drawing courses. AutoCAD is assessed in terms of its capability in meeting the requirements ofthe technical drawing courses.

  7. Molecular mechanism of hypoxia-induced chondrogenesis and its application in in vivo cartilage tissue engineering.

    OpenAIRE

    Duval , Elise; Baugé , Catherine; Andriamanalijaona , Rina; Bénateau , Hervé; Leclercq , Sylvain; Dutoit , Soizic; Poulain , Laurent; Galéra , Philippe; Boumédiene , Karim

    2012-01-01

    International audience; Cartilage engineering is one of the most challenging issue in regenerative medicine, due to its limited self-ability to repair. Here, we assessed engineering of cartilage tissue starting from human bone marrow (hBM) stem cells under hypoxic environment and delineated the mechanism whereby chondrogenesis could be conducted without addition of exogenous growth factors. hBM stem cells were cultured in alginate beads and chondrogenesis was monitored by chondrocyte phenotyp...

  8. A study of competence in mathematics and mechanics in an engineering curriculum

    Science.gov (United States)

    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.

  9. Silicon-based tracking system: Mechanical engineering and design

    International Nuclear Information System (INIS)

    Miller, W.O.; Gamble, M.T.; Thompson, T.C.; Woloshun, K.A.; Reid, R.S.; Hanlon, J.A.; Michaud, F.D.; Dransfield, G.D.; Ziock, H.J.; Palounek, A.P.

    1992-01-01

    The Silicon Tracking System (STS) is composed of silicon strip detectors arranged by both in a cylindrical array and an array of flat panels about the interaction region. The cylindrical array is denoted the central region and the flat panel arrays, which are normal to the beam axis, we denoted the forward regions. The overall length of the silicon array is 5.16 m and the maximum diameter is 0.93 m. The Silicon Tracking System Conceptual Design Report, should be consulted for the body of analysis performed to quantify the present design concept. For the STS to achieve its physics goals, the mechanical structures and services must support 17 m 2 of silicon detectors and stabilize their positions to within 5 μm, uniformly cool the detector the system to O degrees C and at the same time potentially remove up to 13 kW of waste heat generated by the detector electronics, provide up to 3400 A of current to supply the 6.5 million electronics channels, and supply of control and data transmission lines for those channels. These objectives must be achieved in a high ionizing radiation environment, using virtually no structural mass and only low-Z materials. The system must be maintainable during its 10 year operating life

  10. Fast-Response electric drives of Mechanical Engineering objects

    Science.gov (United States)

    Doykina, L. A.; Bukhanov, S. S.; Gryzlov, A. A.

    2018-03-01

    The article gives a solution to the problem of increasing the speed in the electrical drives of machine-building enterprises due to the application of a structure with ISC control. In this case, it is possible to get rid of the speed sensors. It is noted that in this case no circulating pulsations are applied to the input of the control system, caused by a non-identical interface between the sensor and the shaft of the operating mechanism. For detailed modeling, a mathematical model of an electric drive with distributed parameters was proposed. The calculation of such system was carried out by the finite element method. Taking into account the distributed characteristic of the system parameters allowed one to take into account the discrete nature of the electric machine’s work. The simulation results showed that the response time in the control circuit is estimated at a time constant of 0.0015, which is about twice as fast as in traditional vector control schemes.

  11. Mechanical Objects and the Engineering Learner: An Experimental Study of How the Presence of Objects Affects Students' Performance on Engineering Related Tasks

    Science.gov (United States)

    Bairaktarova, Diana N.

    2013-01-01

    People display varying levels of interaction with the mechanical objects in their environment; engineers in particular as makers and users of these objects display a higher level of interaction with them. Investigating the educational potential of mechanical objects in stimulating and supporting learning in engineering is warranted by the fact…

  12. Engineering a Place for Women: A Study of How Departmental Climate Influences the Career Satisfaction of Female Mechanical Engineering Faculty Members

    Science.gov (United States)

    Young, Monica J.

    2012-01-01

    The purpose of this mixed-methods study was to better understand how female mechanical engineering faculty members' career experiences in academia affect their satisfaction. Specifically, the research considered differences in satisfaction reported by female and male mechanical engineering faculty members in terms of: (a) departmental…

  13. Methodologies of Knowledge Discovery from Data and Data Mining Methods in Mechanical Engineering

    Directory of Open Access Journals (Sweden)

    Rogalewicz Michał

    2016-12-01

    Full Text Available The paper contains a review of methodologies of a process of knowledge discovery from data and methods of data exploration (Data Mining, which are the most frequently used in mechanical engineering. The methodologies contain various scenarios of data exploring, while DM methods are used in their scope. The paper shows premises for use of DM methods in industry, as well as their advantages and disadvantages. Development of methodologies of knowledge discovery from data is also presented, along with a classification of the most widespread Data Mining methods, divided by type of realized tasks. The paper is summarized by presentation of selected Data Mining applications in mechanical engineering.

  14. Mechanical stretching for tissue engineering: two-dimensional and three-dimensional constructs.

    Science.gov (United States)

    Riehl, Brandon D; Park, Jae-Hong; Kwon, Il Keun; Lim, Jung Yul

    2012-08-01

    Mechanical cell stretching may be an attractive strategy for the tissue engineering of mechanically functional tissues. It has been demonstrated that cell growth and differentiation can be guided by cell stretch with minimal help from soluble factors and engineered tissues that are mechanically stretched in bioreactors may have superior organization, functionality, and strength compared with unstretched counterparts. This review explores recent studies on cell stretching in both two-dimensional (2D) and three-dimensional (3D) setups focusing on the applications of stretch stimulation as a tool for controlling cell orientation, growth, gene expression, lineage commitment, and differentiation and for achieving successful tissue engineering of mechanically functional tissues, including cardiac, muscle, vasculature, ligament, tendon, bone, and so on. Custom stretching devices and lab-specific mechanical bioreactors are described with a discussion on capabilities and limitations. While stretch mechanotransduction pathways have been examined using 2D stretch, studying such pathways in physiologically relevant 3D environments may be required to understand how cells direct tissue development under stretch. Cell stretch study using 3D milieus may also help to develop tissue-specific stretch regimens optimized with biochemical feedback, which once developed will provide optimal tissue engineering protocols.

  15. The effects of matrix inhomogeneities on the cellular mechanical environment in tissue-engineered cartilage: an in silico investigation

    NARCIS (Netherlands)

    Khoshgoftar, M.; Wilson, W.; Ito, K.; Donkelaar, C.C. van

    2014-01-01

    Mechanical stimulation during cartilage tissue-engineering enhances extracellular matrix (ECM) synthesis and thereby improves the mechanical properties of tissue engineered (TE) cartilage. Generally, these mechanical stimuli are of a fixed magnitude. However, as a result of ECM synthesis and spatial

  16. Advances in Application of Mechanical Stimuli in Bioreactors for Cartilage Tissue Engineering.

    Science.gov (United States)

    Li, Ke; Zhang, Chunqiu; Qiu, Lulu; Gao, Lilan; Zhang, Xizheng

    2017-08-01

    Articular cartilage (AC) is the weight-bearing tissue in diarthroses. It lacks the capacity for self-healing once there are injuries or diseases due to its avascularity. With the development of tissue engineering, repairing cartilage defects through transplantation of engineered cartilage that closely matches properties of native cartilage has become a new option for curing cartilage diseases. The main hurdle for clinical application of engineered cartilage is how to develop functional cartilage constructs for mass production in a credible way. Recently, impressive hyaline cartilage that may have the potential to provide capabilities for treating large cartilage lesions in the future has been produced in laboratories. The key to functional cartilage construction in vitro is to identify appropriate mechanical stimuli. First, they should ensure the function of metabolism because mechanical stimuli play the role of blood vessels in the metabolism of AC, for example, acquiring nutrition and removing wastes. Second, they should mimic the movement of synovial joints and produce phenotypically correct tissues to achieve the adaptive development between the micro- and macrostructure and function. In this article, we divide mechanical stimuli into three types according to forces transmitted by different media in bioreactors, namely forces transmitted through the liquid medium, solid medium, or other media, then we review and summarize the research status of bioreactors for cartilage tissue engineering (CTE), mainly focusing on the effects of diverse mechanical stimuli on engineered cartilage. Based on current researches, there are several motion patterns in knee joints; but compression, tension, shear, fluid shear, or hydrostatic pressure each only partially reflects the mechanical condition in vivo. In this study, we propose that rolling-sliding-compression load consists of various stimuli that will represent better mechanical environment in CTE. In addition, engineers

  17. Microfabrication of a platform to measure and manipulate the mechanics of engineered microtissues.

    Science.gov (United States)

    Ramade, Alexandre; Legant, Wesley R; Picart, Catherine; Chen, Christopher S; Boudou, Thomas

    2014-01-01

    Engineered tissues can be used to understand fundamental features of biology, develop organotypic in vitro model systems, and as engineered tissue constructs for replacing damaged tissue in vivo. However, a key limitation is an inability to test the wide range of parameters that might impact the engineered tissue in a high-throughput manner and in an environment that mimics the three-dimensional (3D) native architecture. We developed a microfabricated platform to generate arrays of microtissues embedded within 3D micropatterned matrices. Microcantilevers simultaneously constrain microtissue formation and report forces generated by the microtissues in real time, opening the possibility to use high-throughput, low-volume screening for studies on engineered tissues. Thanks to the micrometer scale of the microtissues, this platform is also suitable for high-throughput monitoring of drug-induced effect on architecture and contractility in engineered tissues. Moreover, independent variations of the mechanical stiffness of the cantilevers and collagen matrix allow the measurement and manipulation of the mechanics of the microtissues. Thus, our approach will likely provide valuable opportunities to elucidate how biomechanical, electrical, biochemical, and genetic/epigenetic cues modulate the formation and maturation of 3D engineered tissues. In this chapter, we describe the microfabrication, preparation, and experimental use of such microfabricated tissue gauges. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Thermodynamic analysis of a beta-type Stirling engine with rhombic drive mechanism

    International Nuclear Information System (INIS)

    Aksoy, Fatih; Cinar, Can

    2013-01-01

    Highlights: • Thermodynamic analysis of Stirling engine with rhombic-drive mechanism was performed. • The analysis was performed for smooth and grooved displacer cylinders. • The convective heat transfer coefficient was predicted using the experimental results. • The experimental results was compared with the theoretical results. - Abstract: This paper presents a theoretical investigation on kinematic and thermodynamic analysis of a beta type Stirling engine with rhombic-drive mechanism. Variations in the hot and cold volumes of the engine were calculated using kinematic relations. Two different displacer cylinders were investigated: one of them had smooth inner surface and the other had axial slots grooved into the cylinder to increase the heat transfer area. The effects of the slots grooved into the displacer cylinder inner surface on the performance were calculated using nodal analysis in Fortran. The effects of working fluid mass on cyclic work were investigated using 200, 300 and 400 W/m 2 K convective heat transfer coefficients for smooth and grooved displacer cylinders. The variation of engine power with engine speed was obtained by using the same convective heat transfer coefficients and isothermal conditions. The convective heat transfer coefficient was predicted as 104 W/m 2 K using the experimental results measured from the prototype engine under atmospheric conditions. The variation in cyclic work determined by the experimental study was also compared with the theoretical results obtained for different convective heat transfer coefficients and isothermal conditions

  19. Túnel bajo el puerto de Boston

    Directory of Open Access Journals (Sweden)

    Editorial, Equipo

    1963-05-01

    Full Text Available The new tunnel under Boston harbour has been constructed because of the insufficient capacity of a similar, earlier, tunnel to cope with the ever increasing road traffic. This tunnel is 1,550 ms long, and 9.50 ms in external diameter. There are two traffic lanes, each 3.20 ms wide. Inside it is faced with ceramic tiles, has fluorescent lighting, and ventilation is maintained by means of two ducts, one at each entrance, where the necessary compressor and other equipment has been situated. The most interesting feature of this important project is the excavation method adopted for its construction: the tunnel crosses a clay layer, which at certain places is sufficiently fluid to allow a pneumatic shield to be forced through it leaving hardly any debris behind. It will be readily appreciated that this procedure shows an obvious advantage over ordinary methods, in which it is necessary to cut out, and transport to the exterior all the excavated material. The metal sheathing was by the Commercial Shearing and Stamping Co., Youngstown, Ohio.Este nuevo túnel, bajo el puerto de Boston, es una consecuencia de la necesidad imperiosa que se hacía sentir dada la insuficiente capacidad del otro túnel similar antiguo y el aumento continuo del tráfico urbano y por carretera. Tiene 1.550 m de longitud, 9,50 m de diámetro exterior y una calzada con dos bandas de circulación de 3,20 m de anchura cada una. Está revestido ccn baldosa cerámica, iluminado con luz fluorescente, y el aire viciado se ventila y renueva por medio de dos torres de ventilación—una en cada portal—, en las que se han instalado el equipo mecánico adecuado de ventilación y compresores. La parte más interesante de esta importante obra estriba en los procedimientos empleados para llevar a cabo la excavación, pues atraviesa un banco de arcilla que, en ciertos tramos, es suficientemente fluida para permitir dejarse empujar y ceder paso a un escudo neumático que avanza sin apenas

  20. Mechatronics: the future of mechanical engineering; past, present, and a vision for the future

    Science.gov (United States)

    Ramasubramanian, M. K.

    2001-08-01

    Mechatronics is the synergistic integration of precision mechanical engineering, electronics, computational hardware and software in the design of products and processes. Mechatronics, the term coined in Japan in the '70s, has evolved to symbolize what mechanical design engineers do today worldwide. The revolutionary introduction of the microprocessor (or microcontroller) in the early '80s and ever increasing performance-cost ratio has changed the paradigm of mechanical design forever, and has broadened the original definition of mechatronics to include intelligent control and autonomous decision-making. Today, increasing number of new products is being developed at the intersection between traditional disciplines of Engineering, and Computer and Material Sciences. New developments in these traditional disciplines are being absorbed into mechatronics design at an ever-increasing pace. In this paper, a brief history of mechatronics, and several examples of this rapid adaptation of technologies into product design is presented. With the ongoing information technology revolution, especially in wireless communication, smart sensors design (enabled by MEMS technology), and embedded systems engineering, mechatronics design is going through another step change in capabilities and scope. The implications of these developments in mechatronics design in the near future are discussed. Finally, deficiencies in our engineering curriculum to address the needs of the industry to cope up with these rapid changes, and proposed remedies, will also be discussed.

  1. Uranium mine venting during operation of self-propelled Diesel engine mechanisms

    International Nuclear Information System (INIS)

    Hemer, M.

    1983-01-01

    A draft directive has been issued for the ventilation of uranium mines which takes into consideration the concentration of radon daughter products, radon volume activity as well as the concentration of harmful wastes emitted by the Diesel engines of mining mechanisms. The mathematical relations are given for the calculation of the required amount of pure mine winds. Also listed are the technical requirements for ventilation, dust emission and the control and maintenance of mining mechanisms. (M.D.)

  2. Rotation, Reflection, and Frame Changes; Orthogonal tensors in computational engineering mechanics

    Science.gov (United States)

    Brannon, R. M.

    2018-04-01

    Whilst vast literature is available for the most common rotation-related tasks such as coordinate changes, most reference books tend to cover one or two methods, and resources for less-common tasks are scarce. Specialized research applications can be found in disparate journal articles, but a self-contained comprehensive review that covers both elementary and advanced concepts in a manner comprehensible to engineers is rare. Rotation, Reflection, and Frame Changes surveys a refreshingly broad range of rotation-related research that is routinely needed in engineering practice. By illustrating key concepts in computer source code, this book stands out as an unusually accessible guide for engineers and scientists in engineering mechanics.

  3. Reliability in automotive and mechanical engineering determination of component and system reliability

    CERN Document Server

    Bertsche, Bernd

    2008-01-01

    In the present contemporary climate of global competition in every branch of engineering and manufacture it has been shown from extensive customer surveys that above every other attribute, reliability stands as the most desired feature in a finished product. To survive this relentless fight for survival any organisation, which neglect the plea of attaining to excellence in reliability, will do so at a serious cost Reliability in Automotive and Mechanical Engineering draws together a wide spectrum of diverse and relevant applications and analyses on reliability engineering. This is distilled into this attractive and well documented volume and practising engineers are challenged with the formidable task of simultaneously improving reliability and reducing the costs and down-time due to maintenance. The volume brings together eleven chapters to highlight the importance of the interrelated reliability and maintenance disciplines. They represent the development trends and progress resulting in making this book ess...

  4. Proceedings of the fourteenth symposium on energy engineering sciences: Mechanical sciences; Solids and fluids

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-10-01

    The Engineering Research Program is charged with the identification, initiation, and management of fundamental research on broad, generic topics addressing energy-related engineering problems. Its stated goals are: (1) to improve and extend the body of knowledge underlying current engineering practice so as to create new options for enhancing energy savings and production, for prolonging useful life of energy-related structures and equipment and for developing advanced manufacturing technologies and materials processing with emphasis on reducing costs with improved industrial production and performance quality; (2) to expand the store of fundamental concepts for solving anticipated and unforeseen engineering problems in the energy technologies. The 26 papers in this proceedings are arranged in the following topical sections: superconductors (4 papers); materials (7); controls (4); fluid mechanics (7); and thin films (4). Papers have been processed separately for inclusion on the data base.

  5. Was Babbage's Analytical Engine intended to be a mechanical model of the mind?

    Science.gov (United States)

    Green, Christopher D

    2005-02-01

    In the 1830s, Charles Babbage worked on a mechanical computer he dubbed the Analytical Engine. Although some people around Babbage described his invention as though it had authentic mental powers, Babbage refrained from making such claims. He does not, however, seem to have discouraged those he worked with from mooting the idea publicly. This article investigates whether (1) the Analytical Engine was the focus of a covert research program into the mechanism of mentality; (2) Babbage opposed the idea that the Analytical Engine had mental powers but allowed his colleagues to speculate as they saw fit; or (3) Babbage believed such claims to be fanciful, but cleverly used the publicity they engendered to draw public and political attention to his project.

  6. Cam Design Projects in an Advanced CAD Course for Mechanical Engineers

    Science.gov (United States)

    Ault, H. K.

    2009-01-01

    The objective of this paper is to present applications of solid modeling aimed at modeling of complex geometries such as splines and blended surfaces in advanced CAD courses. These projects, in CAD-based Mechanical Engineering courses, are focused on the use of the CAD system to solve design problems for applications in machine design, namely the…

  7. The Faculty Perspective on Holistic and Systems Thinking in American and Australian Mechanical Engineering Programmes

    Science.gov (United States)

    Kellam, N. N.; Maher, M. A.; Peters, W. H.

    2008-01-01

    This research effort examined current mechanical engineering educational programmes in America and Australia to determine the degree of holistic, systems thinking of each programme. Faculty from ten American universities and ten Australian universities participated in online surveys and interviews. Resulting data analysis and interpretation…

  8. Identifying and Investigating Difficult Concepts in Engineering Mechanics and Electric Circuits. Research Brief

    Science.gov (United States)

    Streveler, Ruth; Geist, Monica; Ammerman, Ravel; Sulzbach, Candace; Miller, Ronald; Olds, Barbara; Nelson, Mary

    2007-01-01

    This study extends ongoing work to identify difficult concepts in thermal and transport science and measure students' understanding of those concepts via a concept inventory. Two research questions provided the focal point: "What important concepts in electric circuits and engineering mechanics do students find difficult to learn?" and…

  9. Preliminary Assessment of the Emporium Model in a Redesigned Engineering Mechanics Course

    Science.gov (United States)

    Rais-Rohani, Masoud; Walters, Andrew

    2014-01-01

    A lecture-based engineering mechanics course (Statics) is redesigned using the Emporium model. Whereas students study the material outside of class via asynchronous online delivery of the content and instructional videos, they do all the other activities (e.g., assignments, tests) either individually or in groups inside the classroom. Computer-…

  10. Student Motivation in Low-Stakes Assessment Contexts: An Exploratory Analysis in Engineering Mechanics

    Science.gov (United States)

    Musekamp, Frank; Pearce, Jacob

    2016-01-01

    The goal of this paper is to examine the relationship of student motivation and achievement in low-stakes assessment contexts. Using Pearson product-moment correlations and hierarchical linear regression modelling to analyse data on 794 tertiary students who undertook a low-stakes engineering mechanics assessment (along with the questionnaire of…

  11. An integrated finite-element approach to mechanics, transport and biosynthesis in tissue engineering

    NARCIS (Netherlands)

    Sengers, B.G.; Oomens, C.W.J.; Baaijens, F.P.T.

    2004-01-01

    A finite-element approach was formulated, aimed at enabling an integrated study of mechanical and biochemical factors that control the functional development of tissue engineered constructs. A nonlinear biphasic displacement-velocity-pressure description was combined with adjective and diffusive

  12. Effectiveness of Using a Video Game to Teach a Course in Mechanical Engineering

    Science.gov (United States)

    Coller, B. D.; Scott, M. J.

    2009-01-01

    One of the core courses in the undergraduate mechanical engineering curriculum has been completely redesigned. In the new numerical methods course, all assignments and learning experiences are built around a video/computer game. Students are given the task of writing computer programs to race a simulated car around a track. In doing so, students…

  13. Engine Performance (Section C: Emission Control Systems). Auto Mechanics Curriculum Guide. Module 3. Instructor's Guide.

    Science.gov (United States)

    Rains, Larry

    This engine performance (emission control systems) module is one of a series of competency-based modules in the Missouri Auto Mechanics Curriculum Guide. Topics of this module's five units are: positive crankcase ventilation (PCV) and evaporative emission control systems; exhaust gas recirculation (EGR); air injection and catalytic converters;…

  14. Engine Tune-up Service. Unit 6: Emission Control Systems. Student Guide. Automotive Mechanics Curriculum.

    Science.gov (United States)

    Bacon, E. Miles

    This student guide is for Unit 6, Emission Control Systems, in the Engine Tune-Up Service portion of the Automotive Mechanics Curriculum. It deals with inspecting, testing, and servicing an emission control system. A companion review exercise book and posttests are available separately as CE 031 221-222. An introduction tells how this unit fits…

  15. Engine Tune-Up Service. Unit 5: Fuel and Carburetion Systems. Student Guide. Automotive Mechanics Curriculum.

    Science.gov (United States)

    Goodson, Ludy

    This student guide is for Unit 5, Fuel and Carburetion Systems, in the Engine Tune-Up Service portion of the Automotive Mechanics Curriculum. It deals with inspecting and servicing the fuel and carburetion systems. A companion review exercise book and posttests are available separately as CE 031 218-219. An introduction tells how this unit fits…

  16. Engine Tune-Up Service. Unit 4: Secondary Circuit. Student Guide. Automotive Mechanics Curriculum.

    Science.gov (United States)

    Bacon, E. Miles

    This student guide is for Unit 4, Secondary Circuit, in the Engine Tune-Up Service portion of the Automotive Mechanics Curriculum. It deals with how to test and service the secondary ignition circuit. A companion review exercise book and posttests are available separately as CE 031 215-216. An introduction tells how this unit fits into the total…

  17. Engine Tune-Up Service. Unit 3: Primary Circuit. Student Guide. Automotive Mechanics Curriculum.

    Science.gov (United States)

    Bacon, E. Miles

    This student guide is for Unit 3, Primary Circuit, in the Engine Tune-Up Service portion of the Automotive Mechanics Curriculum. It deals with how to test the primary ignition circuit. A companion review exercise book and posttests are available separately as CE 031 212-213. An introduction tells how this unit fits into the total tune-up service,…

  18. Engine Tune-up Service. Unit 2: Charging System. Student Guide. Automotive Mechanics Curriculum.

    Science.gov (United States)

    Richardson, Roger L.; Bacon, E. Miles

    This student guide is for Unit 2, Charging System, in the Engine Tune-Up Service portion of the Automotive Mechanics Curriculum. It deals with how to test the charging system. A companion review exercise book and posttests are available separately as CE 031 209-210. An introduction tells how this unit fits into the total tune-up service, defines…

  19. Nondestructive and noninvasive assessment of mechanical properties in heart valve tissue engineering

    NARCIS (Netherlands)

    Kortsmit, J.; Driessen, N.J.B.; Rutten, M.C.M.; Baaijens, F.P.T.

    2009-01-01

    Despite recent progress, mechanical behavior of tissue-engineered heart valves still needs improvement when native aortic valves are considered as a benchmark. Although it is known that cyclic straining enhances tissue formation, optimal loading protocols have not been defined yet. To obtain a

  20. Multi-scale mechanical characterization of scaffolds for heart valve tissue engineering

    NARCIS (Netherlands)

    Argento, G.; Simonet, M.; Oomens, C.W.J.; Baaijens, F.P.T.

    2012-01-01

    Electrospinning is a promising technology to produce scaffolds for cardiovascular tissue engineering. Each electrospun scaffold is characterized by a complex micro-scale structure that is responsible for its macroscopic mechanical behavior. In this study, we focus on the development and the

  1. Assessing Cognitive Load Theory to Improve Student Learning for Mechanical Engineers

    Science.gov (United States)

    Impelluso, Thomas J.

    2009-01-01

    A computer programming class for students of mechanical engineering was redesigned and assessed: Cognitive Load Theory was used to redesign the content; online technologies were used to redesign the delivery. Student learning improved and the dropout rate was reduced. This article reports on both attitudinal and objective assessment: comparing…

  2. General Mechanical Repair. Minor Automotive Maintenance, Small Engine [Repair, and] Welding: Curriculum Guide and Lesson Plans.

    Science.gov (United States)

    Hamlin, Larry

    This document contains a curriculum guide and lesson plans for a general mechanical repair course with three sections: minor automotive maintenance, small engine repair, and welding. The curriculum guide begins with a matrix that relates the lesson plans to essential elements of math, science, language arts, and social studies and to Texas…

  3. General Mechanical Repair. Minor Automotive Maintenance, Small Engine [Repair, and] Welding: Student Manual.

    Science.gov (United States)

    Hamlin, Larry

    This document is a student manual for a general mechanical repair course. Following a list of common essential elements of trade and industrial education, the manual is divided into three sections. The first section, on minor automotive maintenance, contains 13 units: automotive shop safety; engine principles; fuel system operation and repair;…

  4. Strategies for the Cooperation of Educational Institutions and Companies in Mechanical Engineering

    Science.gov (United States)

    Kettunen, Juha

    2006-01-01

    Purpose: The purpose of this study is to analyse the strategic planning of the Centre for Mechanical Engineering, which is a joint venture of educational institutions and companies in Southwest Finland. Design/methodology/approach: The paper presents the strategies of focus and cost efficiency and how the selected strategies can be adjusted…

  5. PREFACE: 3rd International Conference of Mechanical Engineering Research (ICMER 2015)

    Science.gov (United States)

    Mamat, Riazalman; Rahman, Mustafizur; Mohd. Zuki Nik Mohamed, Nik; Che Ghani, Saiful Anwar; Harun, Wan Sharuzi Wan

    2015-12-01

    The 3rd ICMER2015 is the continuity of the NCMER2010. The year 2010 represents a significant milestone in the history for Faculty of Mechanical Engineering, Universiti Malaysia Pahang (UMP) Malaysia with the organization of the first and second national level conferences (1st and 2nd NCMER) at UMP on May 26-27 and Dec 3-4 2010. The Faculty then changed the name from National Conference on Mechanical Engineering Research (NCMER) to International Conference on Mechanical Engineering Research (ICMER) in 2011 and this year, 2015 is our 3rd ICMER. These proceedings contain the selected scientific manuscripts submitted to the conference. It is with great pleasure to welcome you to the "International Conference on Mechanical Engineering Research (ICMER2015)" that is held at Zenith Hotel, Kuantan, Malaysia. The call for papers attracted submissions of over two hundred abstracts from twelve different countries including Japan, Iran, China, Kuwait, Indonesia, Norway, Philippines, Morocco, Germany, UAE and more. The scientific papers published in these proceedings have been revised and approved by the technical committee of the 3rd ICMER2015. All of the papers exhibit clear, concise, and precise expositions that appeal to a broad international readership interested in mechanical engineering, combustion, metallurgy, materials science as well as in manufacturing and biomechanics. The reports present original ideas or results of general significance supported by clear reasoning and compelling evidence, and employ methods, theories and practices relevant to the research. The authors clearly state the questions and the significance of their research to theory and practice, describe how the research contributes to new knowledge, and provide tables and figures that meaningfully add to the narrative. In this edition of ICMER representatives attending are from academia, industry, governmental and private sectors. The plenary and invited speakers will present, discuss, promote and

  6. A Typology of Techniques for Motivation of Personnel at Mechanical Engineering Enterprises

    Directory of Open Access Journals (Sweden)

    Melnyk Olga G.

    2015-03-01

    Full Text Available The purpose of the article is to develop a typology of techniques for motivation of personnel at mechanical engineering enterprises providing for systematization of their forms on the basis of a number of the existing features and identified new ones, which are justified by the requirements of today. There has been proved the fragmentary character of developments in this area making it impossible to form basic prerequisites for studying the concept. It has been found that certain features of the typology of methods for motivating employees may also be signs of a typology of techniques for motivation of personnel at enterprises of mechanical engineering industry. Among the current signs of a typology of techniques for motivation of personnel at mechanical engineering enterprises it is proposed to use the following ones: the nature of the impact; results obtained, object of the impact; direction; nature of the objectives; scope of the anticipated changes in the existing motivation system; nature of the needs, at which the techniques are directed. In addition, expediency of introducing new features of the typology, namely: the novelty level (classic and innovative motivation techniques, level of individualization (individual and standard; level of formalization (formalized at the high, medium and low level, source of the need for formation and implementation (the techniques, which necessity is specified by the enterprise, and the techniques, which necessity is specified by the business environment, origin («field» and «office» ones. These results allow forming a holistic view of the diversity of techniques for motivation of personnel at mechanical engineering enterprises as well as reasonable choosing among them their individual types at improving the motivation system. Prospects for further research in this direction should be allocation and systematization of the factors influencing the choice of one or another technique for motivation of

  7. PREFACE: 1st International Conference on Mechanical Engineering Research 2011 (ICMER2011)

    Science.gov (United States)

    Abu Bakar, Rosli

    2012-09-01

    The year 2010 represented a significant milestone in the history of the Mechanical Engineering community with the organization of the first and second national level conferences (National Conference in Mechanical Engineering for Research, 1st and 2nd NCMER) at Universiti Malaysia Pahang on 26-27 May and 3-4 December 2010. The conferences attracted a large number of delegates from different premier academic and research institutions in the country to participate and share their research experiences at the conference. The International Conference on Mechanical Engineering Research (ICMER 2011) followed on from the first and second conferences due to good support from researchers. The ICMER 2011 is a good platform for researchers and postgraduate students to present their latest finding in research. The conference covers a wide range of topics including the internal combustion engine, machining processes, heat and mass transfer, fuel, biomechanical analysis, aerodynamic analysis, thermal comfort, computational techniques, design and simulation, automotive transmission, optimization techniques, hybrid electric vehicles, engine vibration, heat exchangers, finite element analysis, computational fluid dynamics, green energy, vehicle dynamics renewable energy, combustion, design, product development, advanced experimentation techniques, to name but a few. The international conference has helped to bridge the gap between researchers working at different institutions and in different countries to share their knowledge and has helped to motivate young scientists with their research. This has also given some clear direction for further research from the deliberations of the conference. Several people have contributed in different ways to the success of the conference. We thank the keynote speakers and all authors of the contributed papers, for the cooperation rendered to us in the publication of the CD conference proceedings. In particular, we would like to place on record our

  8. The history of theoretical, material and computational mechanics mathematics meets mechanics and engineering

    CERN Document Server

    2014-01-01

    This collection of 23 articles is the output of lectures in special sessions on “The History of Theoretical, Material and Computational Mechanics” within the yearly conferences of the GAMM in the years 2010 in Karlsruhe, Germany, 2011 in Graz, Austria, and in 2012 in Darmstadt, Germany; GAMM is the “Association for Applied Mathematics and Mechanics”, founded in 1922 by Ludwig Prandtl and Richard von Mises. The contributions in this volume discuss different aspects of mechanics. They are related to solid and fluid mechanics in general and to specific problems in these areas including the development of numerical solution techniques. In the first part the origins and developments of conservation principles in mechanics and related variational methods are treated together with challenging applications from the 17th to the 20th century. Part II treats general and more specific aspects of material theories of deforming solid continua and porous soils. and Part III presents important theoretical and enginee...

  9. A Robust Method to Generate Mechanically Anisotropic Vascular Smooth Muscle Cell Sheets for Vascular Tissue Engineering.

    Science.gov (United States)

    Backman, Daniel E; LeSavage, Bauer L; Shah, Shivem B; Wong, Joyce Y

    2017-06-01

    In arterial tissue engineering, mimicking native structure and mechanical properties is essential because compliance mismatch can lead to graft failure and further disease. With bottom-up tissue engineering approaches, designing tissue components with proper microscale mechanical properties is crucial to achieve the necessary macroscale properties in the final implant. This study develops a thermoresponsive cell culture platform for growing aligned vascular smooth muscle cell (VSMC) sheets by photografting N-isopropylacrylamide (NIPAAm) onto micropatterned poly(dimethysiloxane) (PDMS). The grafting process is experimentally and computationally optimized to produce PNIPAAm-PDMS substrates optimal for VSMC attachment. To allow long-term VSMC sheet culture and increase the rate of VSMC sheet formation, PNIPAAm-PDMS surfaces were further modified with 3-aminopropyltriethoxysilane yielding a robust, thermoresponsive cell culture platform for culturing VSMC sheets. VSMC cell sheets cultured on patterned thermoresponsive substrates exhibit cellular and collagen alignment in the direction of the micropattern. Mechanical characterization of patterned, single-layer VSMC sheets reveals increased stiffness in the aligned direction compared to the perpendicular direction whereas nonpatterned cell sheets exhibit no directional dependence. Structural and mechanical anisotropy of aligned, single-layer VSMC sheets makes this platform an attractive microstructural building block for engineering a vascular graft to match the in vivo mechanical properties of native arterial tissue. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Optimization of rhombic drive mechanism used in beta-type Stirling engine based on dimensionless analysis

    International Nuclear Information System (INIS)

    Cheng, Chin-Hsiang; Yang, Hang-Suin

    2014-01-01

    In the present study, optimization of rhombic drive mechanism used in a beta-type Stirling engine is performed based on a dimensionless theoretical model toward maximization of shaft work output. Displacements of the piston and the displacer with the rhombic drive mechanism and variations of volumes and pressure in the chambers of the engine are firstly expressed in dimensionless form. Secondly, Schmidt analysis is incorporated with Senft's shaft work theory to build a dimensionless thermodynamic model, which is employed to yield the dimensionless shaft work. The dimensionless model is verified with experimental data. It is found that the relative error between the experimental and the theoretical data in dimensionless shaft work is lower than 5.2%. This model is also employed to investigate the effects of the influential geometric parameters on the shaft work, and the optimization of these parameters is attempted. Eventually, design charts that help design the optimal geometry of the rhombic drive mechanism are presented in this report. - Highlights: • Specifically dealing with optimization of rhombic-drive mechanism used in Stirling engine based on dimensionless model. • Propose design charts that help determine the optimal geometric parameters of the rhombic drive mechanism. • Complete study of influential factors affecting the shaft work output

  11. Release mechanisms from shallow engineered trenches used as repositories for radioactive wastes

    International Nuclear Information System (INIS)

    Locke, J.; Wood, E.

    1987-05-01

    This report has been written for the Department of the Environment as part of their radioactive waste management research programme. The aim has been to identify release mechanisms of radioactivity from fully engineered trenches of the LAND 2 type and, to identify the data needed for their assessment. No direct experimental work has been involved. The report starts with a brief background to UK strategy and outlines a basic disposal system. It gives reviews of existing experience of low level radioactive waste disposal from LAND 1 trenches and of UK experience of toxic waste disposal to provide a practical basis for the next section which covers the implications of identified release mechanisms on the design requirements for an engineered trench. From these design requirements and their interaction with potential site conditions (both saturated and unsaturated zone sites are considered) an assessment of radionuclide release mechanism is made. (author)

  12. Renovation of a Mechanical Engineering Senior Design Class to an Industry-Tied and Team-Oriented Course

    Science.gov (United States)

    Liu, Yucheng

    2017-01-01

    In this work, an industry-based and team-oriented education model was established based on a traditional mechanical engineering (ME) senior design class in order to better prepare future engineers and leaders so as to meet the increasing demand for high-quality engineering graduates. In the renovated curriculum, industry-sponsored projects became…

  13. Design considerations and challenges for mechanical stretch bioreactors in tissue engineering.

    Science.gov (United States)

    Lei, Ying; Ferdous, Zannatul

    2016-05-01

    With the increase in average life expectancy and growing aging population, lack of functional grafts for replacement surgeries has become a severe problem. Engineered tissues are a promising alternative to this problem because they can mimic the physiological function of the native tissues and be cultured on demand. Cyclic stretch is important for developing many engineered tissues such as hearts, heart valves, muscles, and bones. Thus a variety of stretch bioreactors and corresponding scaffolds have been designed and tested to study the underlying mechanism of tissue formation and to optimize the mechanical conditions applied to the engineered tissues. In this review, we look at various designs of stretch bioreactors and common scaffolds and offer insights for future improvements in tissue engineering applications. First, we summarize the requirements and common configuration of stretch bioreactors. Next, we present the features of different actuating and motion transforming systems and their applications. Since most bioreactors must measure detailed distributions of loads and deformations on engineered tissues, techniques with high accuracy, precision, and frequency have been developed. We also cover the key points in designing culture chambers, nutrition exchanging systems, and regimens used for specific tissues. Since scaffolds are essential for providing biophysical microenvironments for residing cells, we discuss materials and technologies used in fabricating scaffolds to mimic anisotropic native tissues, including decellularized tissues, hydrogels, biocompatible polymers, electrospinning, and 3D bioprinting techniques. Finally, we present the potential future directions for improving stretch bioreactors and scaffolds. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:543-553, 2016. © 2016 American Institute of Chemical Engineers.

  14. Gelatin Scaffolds with Controlled Pore Structure and Mechanical Property for Cartilage Tissue Engineering.

    Science.gov (United States)

    Chen, Shangwu; Zhang, Qin; Nakamoto, Tomoko; Kawazoe, Naoki; Chen, Guoping

    2016-03-01

    Engineering of cartilage tissue in vitro using porous scaffolds and chondrocytes provides a promising approach for cartilage repair. However, nonuniform cell distribution and heterogeneous tissue formation together with weak mechanical property of in vitro engineered cartilage limit their clinical application. In this study, gelatin porous scaffolds with homogeneous and open pores were prepared using ice particulates and freeze-drying. The scaffolds were used to culture bovine articular chondrocytes to engineer cartilage tissue in vitro. The pore structure and mechanical property of gelatin scaffolds could be well controlled by using different ratios of ice particulates to gelatin solution and different concentrations of gelatin. Gelatin scaffolds prepared from ≥70% ice particulates enabled homogeneous seeding of bovine articular chondrocytes throughout the scaffolds and formation of homogeneous cartilage extracellular matrix. While soft scaffolds underwent cellular contraction, stiff scaffolds resisted cellular contraction and had significantly higher cell proliferation and synthesis of sulfated glycosaminoglycan. Compared with the gelatin scaffolds prepared without ice particulates, the gelatin scaffolds prepared with ice particulates facilitated formation of homogeneous cartilage tissue with significantly higher compressive modulus. The gelatin scaffolds with highly open pore structure and good mechanical property can be used to improve in vitro tissue-engineered cartilage.

  15. A Guide for Using Mechanical Stimulation to Enhance Tissue-Engineered Articular Cartilage Properties.

    Science.gov (United States)

    Salinas, Evelia Y; Hu, Jerry C; Athanasiou, Kyriacos

    2018-04-26

    The use of tissue-engineered articular cartilage (TEAC) constructs has the potential to become a powerful treatment option for cartilage lesions resulting from trauma or early stages of pathology. Although fundamental tissue-engineering strategies based on the use of scaffolds, cells, and signals have been developed, techniques that lead to biomimetic AC constructs that can be translated to in vivo use are yet to be fully confirmed. Mechanical stimulation during tissue culture can be an effective strategy to enhance the mechanical, structural, and cellular properties of tissue-engineered constructs toward mimicking those of native AC. This review focuses on the use of mechanical stimulation to attain and enhance the properties of AC constructs needed to translate these implants to the clinic. In vivo, mechanical loading at maximal and supramaximal physiological levels has been shown to be detrimental to AC through the development of degenerative changes. In contrast, multiple studies have revealed that during culture, mechanical stimulation within narrow ranges of magnitude and duration can produce anisotropic, mechanically robust AC constructs with high cellular viability. Significant progress has been made in evaluating a variety of mechanical stimulation techniques on TEAC, either alone or in combination with other stimuli. These advancements include determining and optimizing efficacious loading parameters (e.g., duration and frequency) to yield improvements in construct design criteria, such as collagen II content, compressive stiffness, cell viability, and fiber organization. With the advancement of mechanical stimulation as a potent strategy in AC tissue engineering, a compendium detailing the results achievable by various stimulus regimens would be of great use for researchers in academia and industry. The objective is to list the qualitative and quantitative effects that can be attained when direct compression, hydrostatic pressure, shear, and tensile

  16. Mathematical Modeling of Uniaxial Mechanical Properties of Collagen Gel Scaffolds for Vascular Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Ramiro M. Irastorza

    2015-01-01

    Full Text Available Small diameter tissue-engineered arteries improve their mechanical and functional properties when they are mechanically stimulated. Applying a suitable stress and/or strain with or without a cycle to the scaffolds and cells during the culturing process resides in our ability to generate a suitable mechanical model. Collagen gel is one of the most used scaffolds in vascular tissue engineering, mainly because it is the principal constituent of the extracellular matrix for vascular cells in human. The mechanical modeling of such a material is not a trivial task, mainly for its viscoelastic nature. Computational and experimental methods for developing a suitable model for collagen gels are of primary importance for the field. In this research, we focused on mechanical properties of collagen gels under unconfined compression. First, mechanical viscoelastic models are discussed and framed in the control system theory. Second, models are fitted using system identification. Several models are evaluated and two nonlinear models are proposed: Mooney-Rivlin inspired and Hammerstein models. The results suggest that Mooney-Rivlin and Hammerstein models succeed in describing the mechanical behavior of collagen gels for cyclic tests on scaffolds (with best fitting parameters 58.3% and 75.8%, resp.. When Akaike criterion is used, the best is the Mooney-Rivlin inspired model.

  17. Mathematical modeling of uniaxial mechanical properties of collagen gel scaffolds for vascular tissue engineering.

    Science.gov (United States)

    Irastorza, Ramiro M; Drouin, Bernard; Blangino, Eugenia; Mantovani, Diego

    2015-01-01

    Small diameter tissue-engineered arteries improve their mechanical and functional properties when they are mechanically stimulated. Applying a suitable stress and/or strain with or without a cycle to the scaffolds and cells during the culturing process resides in our ability to generate a suitable mechanical model. Collagen gel is one of the most used scaffolds in vascular tissue engineering, mainly because it is the principal constituent of the extracellular matrix for vascular cells in human. The mechanical modeling of such a material is not a trivial task, mainly for its viscoelastic nature. Computational and experimental methods for developing a suitable model for collagen gels are of primary importance for the field. In this research, we focused on mechanical properties of collagen gels under unconfined compression. First, mechanical viscoelastic models are discussed and framed in the control system theory. Second, models are fitted using system identification. Several models are evaluated and two nonlinear models are proposed: Mooney-Rivlin inspired and Hammerstein models. The results suggest that Mooney-Rivlin and Hammerstein models succeed in describing the mechanical behavior of collagen gels for cyclic tests on scaffolds (with best fitting parameters 58.3% and 75.8%, resp.). When Akaike criterion is used, the best is the Mooney-Rivlin inspired model.

  18. 77 FR 39996 - Department of Mechanical Engineering, Texas A&M University, Notice of Decision on Application for...

    Science.gov (United States)

    2012-07-06

    ... DEPARTMENT OF COMMERCE International Trade Administration Department of Mechanical Engineering, Texas A&M University, Notice of Decision on Application for Duty-Free Entry of Scientific Instruments...: Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843-3123. Instrument: Arc...

  19. Chondroprotective supplementation promotes the mechanical properties of injectable scaffold for human nucleus pulposus tissue engineering.

    Science.gov (United States)

    Foss, Berit L; Maxwell, Thomas W; Deng, Ying

    2014-01-01

    A result of intervertebral disc (IVD) degeneration, the nucleus pulposus (NP) is no longer able to withstand applied load leading to pain and disability. The objective of this study is to fabricate a tissue-engineered injectable scaffold with chondroprotective supplementation in vitro to improve the mechanical properties of a degenerative NP. Tissue-engineered scaffolds were fabricated using different concentrations of alginate and calcium chloride and mechanically evaluated. Fabrication conditions were based on structural and mechanical resemblance to the native NP. Chondroprotective supplementation, glucosamine (GCSN) and chondroitin sulfate (CS), were added to scaffolds at concentrations of 0:0µg/mL (0:0-S), 125:100µg/mL (125:100-S), 250:200µg/mL (250:200-S), and 500:400µg/mL (500:400-S), GCSN and CS, respectively. Scaffolds were used to fabricate tissue-engineered constructs through encapsulation of human nucleus pulposus cells (HNPCs). The tissue-engineered constructs were collected at days 1, 14, and 28 for biochemical and biomechanical evaluations. Confocal microscopy showed HNPC viability and rounded morphology over the 28 day period. MTT analysis resulted in significant increases in cell proliferation for each group. Collagen type II ELISA quantification and compressive aggregate moduli (HA) showed increasing trends for both 250:200-S and the 500:400-S groups on Day 28 with significantly greater HA compared to 0:0-S group. Glycosaminoglycan and water content decreased for all groups. Results indicate the increased mechanical properties of the 250:200-S and the 500:400-S was due to production of a functional matrix. This study demonstrated potential for a chondroprotective supplemented injectable scaffold to restore biomechanical function of a degenerative disc through the production of a mechanically functional matrix. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Biological and mechanical evaluation of a Bio-Hybrid scaffold for autologous valve tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Jahnavi, S [Stem Cell and Molecular Biology Laboratory, Department of Biotechnology, Indian Institute of Technology Madras, Chennai, TN 600036 (India); Tissue Culture Laboratory, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Poojappura, Trivandrum, Kerala 695012 (India); Saravanan, U [Department of Civil Engineering, Indian Institute of Technology Madras, Chennai, TN 600036 (India); Arthi, N [Stem Cell and Molecular Biology Laboratory, Department of Biotechnology, Indian Institute of Technology Madras, Chennai, TN 600036 (India); Bhuvaneshwar, G S [Department of Engineering Design, Indian Institute of Technology Madras, Chennai, TN 600036 (India); Kumary, T V [Tissue Culture Laboratory, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Poojappura, Trivandrum, Kerala 695012 (India); Rajan, S [Madras Medical Mission, Institute of Cardio-Vascular Diseases, Mogappair, Chennai, Tamil Nadu 600037 (India); Verma, R S, E-mail: vermars@iitm.ac.in [Stem Cell and Molecular Biology Laboratory, Department of Biotechnology, Indian Institute of Technology Madras, Chennai, TN 600036 (India)

    2017-04-01

    Major challenge in heart valve tissue engineering for paediatric patients is the development of an autologous valve with regenerative capacity. Hybrid tissue engineering approach is recently gaining popularity to design scaffolds with desired biological and mechanical properties that can remodel post implantation. In this study, we fabricated aligned nanofibrous Bio-Hybrid scaffold made of decellularized bovine pericardium: polycaprolactone-chitosan with optimized polymer thickness to yield the desired biological and mechanical properties. CD44{sup +}, αSMA{sup +}, Vimentin{sup +} and CD105{sup −} human valve interstitial cells were isolated and seeded on these Bio-Hybrid scaffolds. Subsequent biological evaluation revealed interstitial cell proliferation with dense extra cellular matrix deposition that indicated the viability for growth and proliferation of seeded cells on the scaffolds. Uniaxial mechanical tests along axial direction showed that the Bio-Hybrid scaffolds has at least 20 times the strength of the native valves and its stiffness is nearly 3 times more than that of native valves. Biaxial and uniaxial mechanical studies on valve interstitial cells cultured Bio-Hybrid scaffolds revealed that the response along the axial and circumferential direction was different, similar to native valves. Overall, our findings suggest that Bio-Hybrid scaffold is a promising material for future development of regenerative heart valve constructs in children. - Highlights: • We report detailed biological and mechanical investigations of a Bio-Hybrid scaffold. • Optimized polymer thickness yielded desired biological and mechanical properties. • Bio-Hybrid scaffold revealed hVIC proliferation with dense ECM deposition. • Biaxial testing indicated that Bio-Hybrid scaffolds are mechanically stronger than native valves. • Bio-Hybrid scaffold is a promising material for autologous valve tissue engineering.

  1. Correlation between electrical, mechanical and chemical properties of fresh and used aircraft engine oils

    Science.gov (United States)

    Gajewski, Juliusz B.; Głogowski, Marek J.; Paszkowski, Maciej; Czarnik-Matusewicz, Bogusława

    2011-06-01

    In this paper the results are presented of measurements of electrical, mechanical and chemical properties of fresh and used aircraft engine oils. Oils were used in a four-stroke aircraft engine and their samples were taken after the 50-hour work of the engine. The resistivity, permittivity and viscosity of oils were measured as a function of temperature. Additionally, some measurements of the absorbance spectra and size of particles contained in the oils were carried out. The significant reduction in the resistivity of the used Total oil was observed. The relative permittivity of both used oils was slightly increased. The oil's relative viscosity depends on temperature of oil and given time that elapsed from the very first moment when the shear force was applied in a rheometer. The results obtained allowed one to identify more precisely the chemical and physico-chemical interactions occurring in the tested samples, as compared with a typical infrared spectroscopy.

  2. FAILURE MECHANISMS OF THERMAL BARRIER COATINGS INTERNAL COMBUSTION ENGINES AND llMPROVEMENTS

    Directory of Open Access Journals (Sweden)

    ADNAN PARLAK

    2003-04-01

    Full Text Available MechanicaJ properties of high performance ceramics have been improved to the point where their use in heat engines is possible. The high temperature strength and low thermal expansion properties of bigh performance ceramics offer an advantage over metals in the development of non-water cooling engine. However, because bard environment in diesel engine combustion chamber, solving the problem of durabiUty of TBC is important. DurabiUty of thermal barrier coatings(TBC is liınited by two main failure mechanisms: Therınal expansion nlİsmatch betwcen bond coat and top coat and bond coat oxidation. Both of these can cause failure of the ceramic top coat. Developments of recent years sholv that bond coats \\Vith higher oxidation resistance tend to have better coating system cyclic lives

  3. Correlation between electrical, mechanical and chemical properties of fresh and used aircraft engine oils

    International Nuclear Information System (INIS)

    Gajewski, Juliusz B; Glogowski, Marek J; Paszkowski, Maciej; Czarnik-Matusewicz, Boguslawa

    2011-01-01

    In this paper the results are presented of measurements of electrical, mechanical and chemical properties of fresh and used aircraft engine oils. Oils were used in a four-stroke aircraft engine and their samples were taken after the 50-hour work of the engine. The resistivity, permittivity and viscosity of oils were measured as a function of temperature. Additionally, some measurements of the absorbance spectra and size of particles contained in the oils were carried out. The significant reduction in the resistivity of the used Total oil was observed. The relative permittivity of both used oils was slightly increased. The oil's relative viscosity depends on temperature of oil and given time that elapsed from the very first moment when the shear force was applied in a rheometer. The results obtained allowed one to identify more precisely the chemical and physico-chemical interactions occurring in the tested samples, as compared with a typical infrared spectroscopy.

  4. Modeling the impact of scaffold architecture and mechanical loading on collagen turnover in engineered cardiovascular tissues.

    Science.gov (United States)

    Argento, G; de Jonge, N; Söntjens, S H M; Oomens, C W J; Bouten, C V C; Baaijens, F P T

    2015-06-01

    The anisotropic collagen architecture of an engineered cardiovascular tissue has a major impact on its in vivo mechanical performance. This evolving collagen architecture is determined by initial scaffold microstructure and mechanical loading. Here, we developed and validated a theoretical and computational microscale model to quantitatively understand the interplay between scaffold architecture and mechanical loading on collagen synthesis and degradation. Using input from experimental studies, we hypothesize that both the microstructure of the scaffold and the loading conditions influence collagen turnover. The evaluation of the mechanical and topological properties of in vitro engineered constructs reveals that the formation of extracellular matrix layers on top of the scaffold surface influences the mechanical anisotropy on the construct. Results show that the microscale model can successfully capture the collagen arrangement between the fibers of an electrospun scaffold under static and cyclic loading conditions. Contact guidance by the scaffold, and not applied load, dominates the collagen architecture. Therefore, when the collagen grows inside the pores of the scaffold, pronounced scaffold anisotropy guarantees the development of a construct that mimics the mechanical anisotropy of the native cardiovascular tissue.

  5. Methods for automated semantic definition of manufacturing structures (mBOM) in mechanical engineering companies

    Science.gov (United States)

    Stekolschik, Alexander, Prof.

    2017-10-01

    The bill of materials (BOM), which involves all parts and assemblies of the product, is the core of any mechanical or electronic product. The flexible and integrated management of engineering (Engineering Bill of Materials [eBOM]) and manufacturing (Manufacturing Bill of Materials [mBOM]) structures is the key to the creation of modern products in mechanical engineering companies. This paper presents a method framework for the creation and control of e- and, especially, mBOM. The requirements, resulting from the process of differentiation between companies that produce serialized or engineered-to-order products, are considered in the analysis phase. The main part of the paper describes different approaches to fully or partly automated creation of mBOM. The first approach is the definition of part selection rules in the generic mBOM templates. The mBOM can be derived from the eBOM for partly standardized products by using this method. Another approach is the simultaneous use of semantic rules, options, and parameters in both structures. The implementation of the method framework (selection of use cases) in a standard product lifecycle management (PLM) system is part of the research.

  6. Methodological advances in predicting flow-induced dynamics of plants using mechanical-engineering theory.

    Science.gov (United States)

    de Langre, Emmanuel

    2012-03-15

    The modeling of fluid-structure interactions, such as flow-induced vibrations, is a well-developed field of mechanical engineering. Many methods exist, and it seems natural to apply them to model the behavior of plants, and potentially other cantilever-like biological structures, under flow. Overcoming this disciplinary divide, and the application of such models to biological systems, will significantly advance our understanding of ecological patterns and processes and improve our predictive capabilities. Nonetheless, several methodological issues must first be addressed, which I describe here using two practical examples that have strong similarities: one from agricultural sciences and the other from nuclear engineering. Very similar issues arise in both: individual and collective behavior, small and large space and time scales, porous modeling, standard and extreme events, trade-off between the surface of exchange and individual or collective risk of damage, variability, hostile environments and, in some aspects, evolution. The conclusion is that, although similar issues do exist, which need to be exploited in some detail, there is a significant gap that requires new developments. It is obvious that living plants grow in and adapt to their environment, which certainly makes plant biomechanics fundamentally distinct from classical mechanical engineering. Moreover, the selection processes in biology and in human engineering are truly different, making the issue of safety different as well. A thorough understanding of these similarities and differences is needed to work efficiently in the application of a mechanistic approach to ecology.

  7. Passaged adult chondrocytes can form engineered cartilage with functional mechanical properties: a canine model.

    Science.gov (United States)

    Ng, Kenneth W; Lima, Eric G; Bian, Liming; O'Conor, Christopher J; Jayabalan, Prakash S; Stoker, Aaron M; Kuroki, Keiichi; Cook, Cristi R; Ateshian, Gerard A; Cook, James L; Hung, Clark T

    2010-03-01

    It was hypothesized that previously optimized serum-free culture conditions for juvenile bovine chondrocytes could be adapted to generate engineered cartilage with physiologic mechanical properties in a preclinical, adult canine model. Primary or passaged (using growth factors) adult chondrocytes from three adult dogs were encapsulated in agarose, and cultured in serum-free media with transforming growth factor-beta3. After 28 days in culture, engineered cartilage formed by primary chondrocytes exhibited only small increases in glycosaminoglycan content. However, all passaged chondrocytes on day 28 elaborated a cartilage matrix with compressive properties and glycosaminoglycan content in the range of native adult canine cartilage values. A preliminary biocompatibility study utilizing chondral and osteochondral constructs showed no gross or histological signs of rejection, with all implanted constructs showing excellent integration with surrounding cartilage and subchondral bone. This study demonstrates that adult canine chondrocytes can form a mechanically functional, biocompatible engineered cartilage tissue under optimized culture conditions. The encouraging findings of this work highlight the potential for tissue engineering strategies using adult chondrocytes in the clinical treatment of cartilage defects.

  8. Essentials of the finite element method for mechanical and structural engineers

    CERN Document Server

    Pavlou, Dimitrios G

    2015-01-01

    Fundamental coverage, analytic mathematics, and up-to-date software applications are hard to find in a single text on the finite element method (FEM). Dimitrios Pavlou's Essentials of the Finite Element Method: For Structural and Mechanical Engineers makes the search easier by providing a comprehensive but concise text for those new to FEM, or just in need of a refresher on the essentials. Essentials of the Finite Element Method explains the basics of FEM, then relates these basics to a number of practical engineering applications. Specific topics covered include linear spring elements, bar elements, trusses, beams and frames, heat transfer, and structural dynamics. Throughout the text, readers are shown step-by-step detailed analyses for finite element equations development. The text also demonstrates how FEM is programmed, with examples in MATLAB, CALFEM, and ANSYS allowing readers to learn how to develop their own computer code. Suitable for everyone from first-time BSc/MSc students to practicing mechanic...

  9. Satellite Monitoring of Boston Harbor Water Quality: Initial Investigations

    Science.gov (United States)

    Sheldon, P.; Chen, R. F.; Schaaf, C.; Pahlevan, N.; Lee, Z.

    2016-02-01

    The transformation of Boston Harbor from the "dirtiest in America" to a National Park Area is one of the most remarkable estuarine recoveries in the world. A long-term water quality dataset from 1991 to present exists in Boston Harbor due to a $3. 8 billion lawsuit requiring the harbor clean-up. This project uses discrete water sampling and underway transects with a towed vehicle coordinated with Landsat 7 and Landsat 8 to create surface maps of chlorophyll a (Chl a), dissolved organic matter (CDOM and DOC), total suspended solids (TSS), diffuse attenuation coefficient (Kd_490), and photic depth in Boston Harbor. In addition, 3 buoys have been designed, constructed, and deployed in Boston Harbor that measure Chl a and CDOM fluorescence, optical backscatter, salinity, temperature, and meteorological parameters. We are initially using summer and fall of 2015 to develop atmospheric corrections for conditions in Boston Harbor and develop algorithms for Landsat 8 data to estimate in water photic depth, TSS, Chl a, Kd_490, and CDOM. We will report on initial buoy and cruise data and show 2015 Landsat-derived distributions of water quality parameters. It is our hope that once algorithms for present Landsat imagery can be developed, historical maps of water quality can be constructed using in water data back to 1991.

  10. The Boston Marathon versus the World Marathon Majors.

    Directory of Open Access Journals (Sweden)

    Philip B Maffetone

    Full Text Available To compare finish times across WMM races for Boston, London, Berlin, Chicago and New York Marathons.Race times of the top 10 male and 10 female finishers were analyzed from 2005 to 2014 using the high-performance mixed linear model procedure in the Statistical Analysis System. Venue-to-venue comparisons, as well as comparisons between Boston and other WMM races, with and without factors of temperature, humidity and altitude change were examined.Performance from 2005 to 2014 in the WMM races was found to improve at a rate of ~1% each 7 years. Despite its higher variability, comparison between Boston's estimated mean finishing time and all other venues revealed moderate positive differences, indicating the Boston event to be typically slower than other venues.Across the 10-year study period, performance times improved ~1% each 7 years for both genders for the WMM, with the Boston Marathon being slower on average than other WMM venues. Weather rather than course metrics appeared to impact performance times most.

  11. 2nd International Conference on Mechanical, Manufacturing and Process Plant Engineering

    CERN Document Server

    2017-01-01

    This volume presents selected papers from the 2nd International Conference on Mechanical, Manufacturing and Process Plant Engineering (ICMMPE 2016) which was held from 23rd to 24th November, 2016 in Kuala Lumpur, Malaysia. The proceedings discuss genuine problems of joining technologies that are heart of manufacturing sectors. It discusses the findings of experimental and numerical works from soldering, arc welding to solid state joining technology that faced by current industry. .

  12. The State and Factors of the Economic Dynamics of Mechanical Engineering Enterprises in Ukraine

    Directory of Open Access Journals (Sweden)

    Stadnyk Valentyna V.

    2017-06-01

    Full Text Available The economic dynamics of mechanical engineering enterprises in Ukraine is considered. Steady negative trends in the volumes of production and sales of mechanical engineering products are revealed. The analysis of the export capabilities of the mechanical engineering industry in the context of the main commodity groups showed an increase in the exports of products of the third technological mode, which indicates a decrease in its science intensity. The study of the impact on the state of the industry of general macroeconomic trends, which are reflected in the changes in the Global Competitiveness Index of Ukraine in 2014-2016, demonstrated some improvements in the indicators characterizing the conditions of business management and the results of their innovation activities. With the purpose of assessing the conformity of the directions in innovation activities of enterprises in the industrial sector of Ukraine to the objectives of increasing their innovative potential, there conducted an analysis of the structure of innovation costs, which showed a significant predominance of costs on acquiring equipment, while the implementation of new technologies is carried out mainly on the basis of resource saving and not flexibility; the introduction of product innovations in the market, especially of fundamentally new ones, decreases. The examination of organizational forms of innovation management in mechanical engineering enterprises indicated the lack of complementarity of innovation management and quality management systems, as well as a low level of staff involvement in these improvement processes. The necessity of eliminating these deficiencies in management for increasing the innovative potential of enterprises and achieving cognitive self-sufficiency is underlined. It is noted that the principles underlying modern quality management systems can be used to solve these problems.

  13. Effect of processing methods on the mechanical properties of engineered bamboo

    OpenAIRE

    Sharma, Bhavna; Gatóo, Ana; Ramage, Michael H.

    2015-01-01

    Engineered bamboo is increasingly explored as a material with significant potential for structural applications. The material is comprised of raw bamboo processed into a laminated composite. Commercial methods vary due to the current primary use as an architectural surface material, with processing used to achieve different colours in the material. The present work investigates the effect of two types of processing methods, bleaching and caramelisation, to determine the effect on the mechanic...

  14. Definition of design criteria of mechanical transfer: an interaction between engineering and health areas.

    Science.gov (United States)

    Luz, Taciana Ramos; Echternacht, Eliza Helena de Oliveira

    2012-01-01

    This study aims to analyze the factors that justify the low use of a mechanical transfer in the context of a long-term institution. It is a device intended for internal transportation of individuals who have mobility problems. The analysis involves researchers from the fields of health and engineering in order to generate design criteria that consider the needs of caregivers and patients of this institution. To understand the reality of this site and their specificities, was used Ergonomic Work Analysis.

  15. Economic efficiency substantiation of information products practical online promotion on the mechanical engineering plants

    OpenAIRE

    Roman Oksentyuk

    2015-01-01

    The profitability ratio ROI and its adaptation to calculate the economic efficiency of online advertising campaign has been analyzed. Investment profitability factor enables to estimate to what extent the advertising costs in the global network are justified and profitable for your business. The ratio use on the Ternopil mechanical engineering plants websites as a case study has been investigated by the author of the article. Such indices as the number...

  16. A novel bioreactor to simulate urinary bladder mechanical properties and compliance for bladder functional tissue engineering.

    Science.gov (United States)

    Wei, Xin; Li, Dao-bing; Xu, Feng; Wang, Yan; Zhu, Yu-chun; Li, Hong; Wang, Kun-jie

    2011-02-01

    Bioreactors are pivotal tools for generating mechanical stimulation in functional tissue engineering study. This study aimed to create a bioreactor that can simulate urinary bladder mechanical properties, and to investigate the effects of a mechanically stimulated culture on urothelial cells and bladder smooth muscle cells. We designed a bioreactor to simulate the mechanical properties of bladder. A pressure-record system was used to evaluate the mechanical properties of the bioreactor by measuring the pressure in culture chambers. To test the biocompatibility of the bioreactor, viabilities of urothelial cells and smooth muscle cells cultured in the bioreactor under static and mechanically changed conditions were measured after 7-day culture. To evaluate the effect of mechanical stimulations on the vital cells, urethral cells and smooth muscle cells were cultured in the simulated mechanical conditions. After that, the viability and the distribution pattern of the cells were observed and compared with cells cultured in non-mechanical stimulated condition. The bioreactor system successfully generated waveforms similar to the intended programmed model while maintaining a cell-seeded elastic membrane between the chambers. There were no differences between viabilities of urothelial cells ((91.90 ± 1.22)% vs. (93.14 ± 1.78)%, P > 0.05) and bladder smooth muscle cells ((93.41 ± 1.49)% vs. (92.61 ± 1.34)%, P > 0.05). The viability of cells and tissue structure observation after cultured in simulated condition showed that mechanical stimulation was the only factor affected cells in the bioreactor and improved the arrangement of cells on silastic membrane. This bioreactor can effectively simulate the physiological and mechanical properties of the bladder. Mechanical stimulation is the only factor that affected the viability of cells cultured in the bioreactor. The bioreactor can change the growth behavior of urothelial cells and bladder smooth muscle cells, resulting in

  17. Enabling Robotic Social Intelligence by Engineering Human Social-Cognitive Mechanisms

    DEFF Research Database (Denmark)

    Wiltshire, Travis; Warta, Samantha F.; Barber, Daniel

    2017-01-01

    for artificial cognitive systems. We discuss a recent integrative perspective of social cognition to provide a systematic theoretical underpinning for computational instantiations of these mechanisms. We highlight several commitments of our approach that we refer to as Engineering Human Social Cognition. We...... then provide a series of recommendations to facilitate the development of the perceptual, motor, and cognitive architecture for this proposed artificial cognitive system in future work. For each recommendation, we highlight their relation to the discussed social-cognitive mechanisms, provide the rationale...

  18. Supercharged two-cycle engines employing novel single element reciprocating shuttle inlet valve mechanisms and with a variable compression ratio

    Science.gov (United States)

    Wiesen, Bernard (Inventor)

    2008-01-01

    This invention relates to novel reciprocating shuttle inlet valves, effective with every type of two-cycle engine, from small high-speed single cylinder model engines, to large low-speed multiple cylinder engines, employing spark or compression ignition. Also permitting the elimination of out-of-phase piston arrangements to control scavenging and supercharging of opposed-piston engines. The reciprocating shuttle inlet valve (32) and its operating mechanism (34) is constructed as a single and simple uncomplicated member, in combination with the lost-motion abutments, (46) and (48), formed in a piston skirt, obviating the need for any complex mechanisms or auxiliary drives, unaffected by heat, friction, wear or inertial forces. The reciprocating shuttle inlet valve retains the simplicity and advantages of two-cycle engines, while permitting an increase in volumetric efficiency and performance, thereby increasing the range of usefulness of two-cycle engines into many areas that are now dominated by the four-cycle engine.

  19. Development of Chitosan Scaffolds with Enhanced Mechanical Properties for Intestinal Tissue Engineering Applications.

    Science.gov (United States)

    Zakhem, Elie; Bitar, Khalil N

    2015-10-13

    Massive resections of segments of the gastrointestinal (GI) tract lead to intestinal discontinuity. Functional tubular replacements are needed. Different scaffolds were designed for intestinal tissue engineering application. However, none of the studies have evaluated the mechanical properties of the scaffolds. We have previously shown the biocompatibility of chitosan as a natural material in intestinal tissue engineering. Our scaffolds demonstrated weak mechanical properties. In this study, we enhanced the mechanical strength of the scaffolds with the use of chitosan fibers. Chitosan fibers were circumferentially-aligned around the tubular chitosan scaffolds either from the luminal side or from the outer side or both. Tensile strength, tensile strain, and Young's modulus were significantly increased in the scaffolds with fibers when compared with scaffolds without fibers. Burst pressure was also increased. The biocompatibility of the scaffolds was maintained as demonstrated by the adhesion of smooth muscle cells around the different kinds of scaffolds. The chitosan scaffolds with fibers provided a better candidate for intestinal tissue engineering. The novelty of this study was in the design of the fibers in a specific alignment and their incorporation within the scaffolds.

  20. Design and fabrication of a cryostat for low temperature mechanical testing for the Mechanical and Materials Engineering group at CERN

    CERN Document Server

    Aviles Santillana, I; Gerardin, A; Guinchard, M; Langeslag, S A E; Sgobba, S

    2015-01-01

    Mechanical testing of materials at low temperatures is one of the cornerstones of the Mechanical and Materials Engineering (MME) group at CERN. A long tradition of more than 20 years and a unique know - how of such tests has been developed with an 18 kN double-walled cryostat. Large campaigns of material qualification have been carried out and the mechanical behaviour of materials at 4 K has been vastly studied in sub - size samples for projects like LEP, LHC and its experiments. With the aim of assessing the mechanical properties of materials of higher strength and/or issued from heavy gauge products for which testing standardized specimens of larger cross section might be more adapted, a new 100 kN cryostat capable of hosting different shapes of normalized samples has been carefully designed and fabricated inhouse together with the associated tooling and measurement instrumentation. It has been conceived to be able to adapt to different test frames both dynamic and static, which will be of paramount importa...

  1. Frederick Law Olmsted y el "Emerald Necklace" de Boston

    Directory of Open Access Journals (Sweden)

    Ricardo Austrich

    2003-09-01

    Full Text Available En 1879, Frederick Law Olmsted, el creador del Central Park en Nueva York, Prospect Park en Brooklyn, inventor de la profesión de paisajismo (Landscape Architecture en los EE.UU., arriba a Boston agotado y exhausto. Acaba de renunciar el cargo de paisajista de Central Park, sintiéndose defraudado por las intrigas políticas de la comisión de parques de Nueva York, viajaba a Boston a descansar y pasar un rato con sus amigos en las cercanías de Boston, en Cambridge y Brookline. Su gran amigo, Henry Hobson Richardson, el reconocido arquitecto de la época, vivía y trabajaba en Brookline, y sirve como su anfitrión, tanto como sus amigos en Cambridge.

  2. Mechanical Characterization of Tissue-Engineered Cartilage Using Microscopic Magnetic Resonance Elastography

    Science.gov (United States)

    Yin, Ziying; Schmid, Thomas M.; Yasar, Temel K.; Liu, Yifei; Royston, Thomas J.

    2014-01-01

    Knowledge of mechanical properties of tissue-engineered cartilage is essential for the optimization of cartilage tissue engineering strategies. Microscopic magnetic resonance elastography (μMRE) is a recently developed MR-based technique that can nondestructively visualize shear wave motion. From the observed wave pattern in MR phase images the tissue mechanical properties (e.g., shear modulus or stiffness) can be extracted. For quantification of the dynamic shear properties of small and stiff tissue-engineered cartilage, μMRE needs to be performed at frequencies in the kilohertz range. However, at frequencies greater than 1 kHz shear waves are rapidly attenuated in soft tissues. In this study μMRE, with geometric focusing, was used to overcome the rapid wave attenuation at high frequencies, enabling the measurement of the shear modulus of tissue-engineered cartilage. This methodology was first tested at a frequency of 5 kHz using a model system composed of alginate beads embedded in agarose, and then applied to evaluate extracellular matrix development in a chondrocyte pellet over a 3-week culture period. The shear stiffness in the pellet was found to increase over time (from 6.4 to 16.4 kPa), and the increase was correlated with both the proteoglycan content and the collagen content of the chondrocyte pellets (R2=0.776 and 0.724, respectively). Our study demonstrates that μMRE when performed with geometric focusing can be used to calculate and map the shear properties within tissue-engineered cartilage during its development. PMID:24266395

  3. Mechanical modulation of nascent stem cell lineage commitment in tissue engineering scaffolds.

    Science.gov (United States)

    Song, Min Jae; Dean, David; Knothe Tate, Melissa L

    2013-07-01

    Taking inspiration from tissue morphogenesis in utero, this study tests the concept of using tissue engineering scaffolds as delivery devices to modulate emergent structure-function relationships at early stages of tissue genesis. We report on the use of a combined computational fluid dynamics (CFD) modeling, advanced manufacturing methods, and experimental fluid mechanics (micro-piv and strain mapping) for the prospective design of tissue engineering scaffold geometries that deliver spatially resolved mechanical cues to stem cells seeded within. When subjected to a constant magnitude global flow regime, the local scaffold geometry dictates the magnitudes of mechanical stresses and strains experienced by a given cell, and in a spatially resolved fashion, similar to patterning during morphogenesis. In addition, early markers of mesenchymal stem cell lineage commitment relate significantly to the local mechanical environment of the cell. Finally, by plotting the range of stress-strain states for all data corresponding to nascent cell lineage commitment (95% CI), we begin to "map the mechanome", defining stress-strain states most conducive to targeted cell fates. In sum, we provide a library of reference mechanical cues that can be delivered to cells seeded on tissue engineering scaffolds to guide target tissue phenotypes in a temporally and spatially resolved manner. Knowledge of these effects allows for prospective scaffold design optimization using virtual models prior to prototyping and clinical implementation. Finally, this approach enables the development of next generation scaffolds cum delivery devices for genesis of complex tissues with heterogenous properties, e.g., organs, joints or interface tissues such as growth plates. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Biomimetics: forecasting the future of science, engineering, and medicine

    Directory of Open Access Journals (Sweden)

    Hwang J

    2015-09-01

    Full Text Available Jangsun Hwang,1 Yoon Jeong,1,2 Jeong Min Park,3 Kwan Hong Lee,1,2,4 Jong Wook Hong,1,2 Jonghoon Choi1,2 1Department of Bionano Technology, Graduate School, Hanyang University, Seoul, 2Department of Bionano Engineering, Hanyang University ERICA, Ansan, Korea; 3Department of Biomedical Engineering, Boston University, 4OpenView Venture Partners, Boston, MA, USA Abstract: Biomimetics is the study of nature and natural phenomena to understand the principles of underlying mechanisms, to obtain ideas from nature, and to apply concepts that may benefit science, engineering, and medicine. Examples of biomimetic studies include fluid-drag reduction swimsuits inspired by the structure of shark’s skin, velcro fasteners modeled on burrs, shape of airplanes developed from the look of birds, and stable building structures copied from the backbone of turban shells. In this article, we focus on the current research topics in biomimetics and discuss the potential of biomimetics in science, engineering, and medicine. Our report proposes to become a blueprint for accomplishments that can stem from biomimetics in the next 5 years as well as providing insight into their unseen limitations. Keywords: biomimicry, tissue engineering, biomaterials, nature, nanotechnology, nanomedicine

  5. Identification of the Scale of Changes in Personnel Motivation Techniques at Mechanical-Engineering Enterprises

    Directory of Open Access Journals (Sweden)

    Melnyk Olga G.

    2016-02-01

    Full Text Available The method for identification of the scale of changes in personnel motivation techniques at mechanical-engineering enterprises based on structural and logical sequence of implementation of relevant stages (identification of the mission, strategy and objectives of the enterprise; forecasting the development of the enterprise business environment; SWOT-analysis of actual motivation techniques, deciding on the scale of changes in motivation techniques, choosing providers for changing personnel motivation techniques, choosing an alternative to changing motivation techniques, implementation of changes in motivation techniques; control over changes in motivation techniques. It has been substantiated that the improved method enables providing a systematic and analytical justification for management decisionmaking in this field and choosing the best for the mechanical-engineering enterprise scale and variant of changes in motivation techniques. The method for identification of the scale of changes in motivation techniques at mechanical-engineering enterprises takes into account the previous, current and prospective character. Firstly, the approach is based on considering the past state in the motivational sphere of the mechanical-engineering enterprise; secondly, the method involves identifying the current state of personnel motivation techniques; thirdly, within the method framework the prospective, which is manifested in strategic vision of the enterprise development as well as in forecasting the development of its business environment, is taken into account. The advantage of the proposed method is that the level of its specification may vary depending on the set goals, resource constraints and necessity. Among other things, this method allows integrating various formalized and non-formalized causal relationships in the sphere of personnel motivation at machine-building enterprises and management of relevant processes. This creates preconditions for a

  6. Estrogen inhibits lysyl oxidase and decreases mechanical function in engineered ligaments.

    Science.gov (United States)

    Lee, Cassandra A; Lee-Barthel, Ann; Marquino, Louise; Sandoval, Natalie; Marcotte, George R; Baar, Keith

    2015-05-15

    Women are more likely to suffer an anterior cruciate ligament (ACL) rupture than men, and the incidence of ACL rupture in women rises with increasing estrogen levels. We used an engineered ligament model to determine how an acute rise in estrogen decreases the mechanical properties of ligaments. Using fibroblasts isolated from human ACLs from male or female donors, we engineered ligaments and determined that ligaments made from female ACL cells had more collagen and were equal in strength to those made from male ACL cells. We then treated engineered ligaments for 14 days with low (5 pg/ml), medium (50 pg/ml), or high (500 pg/ml) estrogen, corresponding to the range of in vivo serum estrogen concentrations and found that collagen within the grafts increased without a commensurate increase in mechanical strength. Mimicking the menstrual cycle, with 12 days of low estrogen followed by 2 days of physiologically high estrogen, resulted in a decrease in engineered ligament mechanical function with no change in the amount of collagen in the graft. The decrease in mechanical stiffness corresponded with a 61.7 and 76.9% decrease in the activity of collagen cross-linker lysyl oxidase with 24 and 48 h of high estrogen, respectively. Similarly, grafts treated with the lysyl oxidase inhibitor β-aminoproprionitrile (BAPN) for 24 h showed a significant decrease in ligament mechanical strength [control (CON) = 1.58 ± 0.06 N; BAPN = 1.06 ± 0.13 N] and stiffness (CON = 7.7 ± 0.46 MPa; BAPN = 6.1 ± 0.71 MPa) without changing overall collagen levels (CON = 396 ± 11.5 μg; BAPN = 382 ± 11.6 μg). Together, these data suggest that the rise in estrogen during the follicular phase decreases lysyl oxidase activity in our engineered ligament model and if this occurs in vivo may decrease the stiffness of ligaments and contribute to the elevated rate of ACL rupture in women. Copyright © 2015 the American Physiological Society.

  7. Chitosan fibers with improved biological and mechanical properties for tissue engineering applications.

    Science.gov (United States)

    Albanna, Mohammad Z; Bou-Akl, Therese H; Blowytsky, Oksana; Walters, Henry L; Matthew, Howard W T

    2013-04-01

    The low mechanical properties of hydrogel materials such as chitosan hinder their broad utility for tissue engineering applications. Previous research efforts improved the mechanical properties of chitosan fiber through chemical and physical modifications; however, unfavorable toxicity effects on cells were reported. In this paper, we report the preparation of chitosan fibers with improved mechanical and biocompatibility properties. The structure-property relationships of extruded chitosan fibers were explored by varying acetic acid (AA) concentration, ammonia concentration, annealing temperature and degree of heparin crosslinking. Results showed that optimizing AA concentration to 2vol% improved fiber strength and stiffness by 2-fold. Extruding chitosan solution into 25wt% of ammonia solution reduced fiber diameters and improved fiber strength by 2-fold and stiffness by 3-fold, due to an increase in crystallinity as confirmed by XRD. Fiber annealing further reduced fiber diameter and improved fiber strength and stiffness as temperature increased. Chitosan fibers crosslinked with heparin had increased diameter but lower strength and stiffness properties and higher breaking strain values. When individual parameters were combined, further improvement in fiber mechanical properties was achieved. All mechanically improved fibers and heparin crosslinked fibers promoted valvular interstitial cells (VIC) attachment and growth over 10 day cultures. Our results demonstrate the ability to substantially improve the mechanical properties of chitosan fibers without adversely affecting their biological properties. The investigated treatments offer numerous advantages over previous physical/chemical modifications and thus are expected to expand the utility of chitosan fibers with tunable mechanical properties in various tissue engineering applications. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. A Novel Pulsatile Bioreactor for Mechanical Stimulation of Tissue Engineered Cardiac Constructs

    Directory of Open Access Journals (Sweden)

    Günther Eissner

    2011-07-01

    Full Text Available After myocardial infarction, the implantation of stem cell seeded scaffolds on the ischemic zone represents a promising strategy for restoration of heart function. However, mechanical integrity and functionality of tissue engineered constructs need to be determined prior to implantation. Therefore, in this study a novel pulsatile bioreactor mimicking the myocardial contraction was developed to analyze the behavior of mesenchymal stem cells derived from umbilical cord tissue (UCMSC colonized on titanium-coated polytetrafluorethylene scaffolds to friction stress. The design of the bioreactor enables a simple handling and defined mechanical forces on three seeded scaffolds at physiological conditions. The compact system made of acrylic glass, Teflon®, silicone, and stainless steel allows the comparison of different media, cells and scaffolds. The bioreactor can be gas sterilized and actuated in a standard incubator. Macroscopic observations and pressure-measurements showed a uniformly sinusoidal pulsation, indicating that the bioreactor performed well. Preliminary experiments to determine the adherence rate and morphology of UCMSC after mechanical loadings showed an almost confluent cellular coating without damage on the cell surface. In summary, the bioreactor is an adequate tool for the mechanical stress of seeded scaffolds and offers dynamic stimuli for pre-conditioning of cardiac tissue engineered constructs in vitro.

  9. Multi-scale mechanical response of freeze-dried collagen scaffolds for tissue engineering applications.

    Science.gov (United States)

    Offeddu, Giovanni S; Ashworth, Jennifer C; Cameron, Ruth E; Oyen, Michelle L

    2015-02-01

    Tissue engineering has grown in the past two decades as a promising solution to unresolved clinical problems such as osteoarthritis. The mechanical response of tissue engineering scaffolds is one of the factors determining their use in applications such as cartilage and bone repair. The relationship between the structural and intrinsic mechanical properties of the scaffolds was the object of this study, with the ultimate aim of understanding the stiffness of the substrate that adhered cells experience, and its link to the bulk mechanical properties. Freeze-dried type I collagen porous scaffolds made with varying slurry concentrations and pore sizes were tested in a viscoelastic framework by macroindentation. Membranes made up of stacks of pore walls were indented using colloidal probe atomic force microscopy. It was found that the bulk scaffold mechanical response varied with collagen concentration in the slurry consistent with previous studies on these materials. Hydration of the scaffolds resulted in a more compliant response, yet lesser viscoelastic relaxation. Indentation of the membranes suggested that the material making up the pore walls remains unchanged between conditions, so that the stiffness of the scaffolds at the scale of seeded cells is unchanged; rather, it is suggested that thicker pore walls or more of these result in the increased moduli for the greater slurry concentration conditions. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. Biological and mechanical evaluation of a Bio-Hybrid scaffold for autologous valve tissue engineering.

    Science.gov (United States)

    Jahnavi, S; Saravanan, U; Arthi, N; Bhuvaneshwar, G S; Kumary, T V; Rajan, S; Verma, R S

    2017-04-01

    Major challenge in heart valve tissue engineering for paediatric patients is the development of an autologous valve with regenerative capacity. Hybrid tissue engineering approach is recently gaining popularity to design scaffolds with desired biological and mechanical properties that can remodel post implantation. In this study, we fabricated aligned nanofibrous Bio-Hybrid scaffold made of decellularized bovine pericardium: polycaprolactone-chitosan with optimized polymer thickness to yield the desired biological and mechanical properties. CD44 + , αSMA + , Vimentin + and CD105 - human valve interstitial cells were isolated and seeded on these Bio-Hybrid scaffolds. Subsequent biological evaluation revealed interstitial cell proliferation with dense extra cellular matrix deposition that indicated the viability for growth and proliferation of seeded cells on the scaffolds. Uniaxial mechanical tests along axial direction showed that the Bio-Hybrid scaffolds has at least 20 times the strength of the native valves and its stiffness is nearly 3 times more than that of native valves. Biaxial and uniaxial mechanical studies on valve interstitial cells cultured Bio-Hybrid scaffolds revealed that the response along the axial and circumferential direction was different, similar to native valves. Overall, our findings suggest that Bio-Hybrid scaffold is a promising material for future development of regenerative heart valve constructs in children. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Mapping of Mechanical Strains and Stresses around Quiescent Engineered Three-Dimensional Epithelial Tissues

    Science.gov (United States)

    Gjorevski, Nikolce; Nelson, Celeste M.

    2012-01-01

    Understanding how physical signals guide biological processes requires qualitative and quantitative knowledge of the mechanical forces generated and sensed by cells in a physiologically realistic three-dimensional (3D) context. Here, we used computational modeling and engineered epithelial tissues of precise geometry to define the experimental parameters that are required to measure directly the mechanical stress profile of 3D tissues embedded within native type I collagen. We found that to calculate the stresses accurately in these settings, we had to account for mechanical heterogeneities within the matrix, which we visualized and quantified using confocal reflectance and atomic force microscopy. Using this technique, we were able to obtain traction forces at the epithelium-matrix interface, and to resolve and quantify patterns of mechanical stress throughout the surrounding matrix. We discovered that whereas single cells generate tension by contracting and pulling on the matrix, the contraction of multicellular tissues can also push against the matrix, causing emergent compression. Furthermore, tissue geometry defines the spatial distribution of mechanical stress across the epithelium, which communicates mechanically over distances spanning hundreds of micrometers. Spatially resolved mechanical maps can provide insight into the types and magnitudes of physical parameters that are sensed and interpreted by multicellular tissues during normal and pathological processes. PMID:22828342

  12. Ultrasound Imaging Techniques for Spatiotemporal Characterization of Composition, Microstructure, and Mechanical Properties in Tissue Engineering.

    Science.gov (United States)

    Deng, Cheri X; Hong, Xiaowei; Stegemann, Jan P

    2016-08-01

    Ultrasound techniques are increasingly being used to quantitatively characterize both native and engineered tissues. This review provides an overview and selected examples of the main techniques used in these applications. Grayscale imaging has been used to characterize extracellular matrix deposition, and quantitative ultrasound imaging based on the integrated backscatter coefficient has been applied to estimating cell concentrations and matrix morphology in tissue engineering. Spectral analysis has been employed to characterize the concentration and spatial distribution of mineral particles in a construct, as well as to monitor mineral deposition by cells over time. Ultrasound techniques have also been used to measure the mechanical properties of native and engineered tissues. Conventional ultrasound elasticity imaging and acoustic radiation force imaging have been applied to detect regions of altered stiffness within tissues. Sonorheometry and monitoring of steady-state excitation and recovery have been used to characterize viscoelastic properties of tissue using a single transducer to both deform and image the sample. Dual-mode ultrasound elastography uses separate ultrasound transducers to produce a more potent deformation force to microscale characterization of viscoelasticity of hydrogel constructs. These ultrasound-based techniques have high potential to impact the field of tissue engineering as they are further developed and their range of applications expands.

  13. Mini-Symposium on Micromechanics at the CSME Mechanical Engineering Forum

    CERN Document Server

    Muschik, W

    1991-01-01

    This volume contains the lectures presented at the mini-symposium on "Micromechanics" held in conjunction with the CSME Mechanical Engineer­ ing Forum 1990 between the 3rd and 8th June, 1990 at the University of Toronto, Canada. The expressed purpose of this symposium was to discuss some recent developments in the Micromechanics of Materials and how ad­ vances in this field now relate to the solution of practical engineer­ ing problems. Due to the time limit set for this section of the Engineer­ ing Forum as well as the restriction on the number of papers to be pre­ sented, it was not possible to cover a much wider range of topics. How­ ever, an attempt was made to include the most important advances asso­ ciated with the progress made in micromechanics in its application to material science and engineering over the past decade. Thus, the topics are concerned with: the fundamental aspects of the thermodynamics of structured solids (part I), - the micromechanical behaviour of alloys (part II), - the mod...

  14. Manufacturing of hydrogel biomaterials with controlled mechanical properties for tissue engineering applications.

    Science.gov (United States)

    Vedadghavami, Armin; Minooei, Farnaz; Mohammadi, Mohammad Hossein; Khetani, Sultan; Rezaei Kolahchi, Ahmad; Mashayekhan, Shohreh; Sanati-Nezhad, Amir

    2017-10-15

    Hydrogels have been recognized as crucial biomaterials in the field of tissue engineering, regenerative medicine, and drug delivery applications due to their specific characteristics. These biomaterials benefit from retaining a large amount of water, effective mass transfer, similarity to natural tissues and the ability to form different shapes. However, having relatively poor mechanical properties is a limiting factor associated with hydrogel biomaterials. Controlling the biomechanical properties of hydrogels is of paramount importance. In this work, firstly, mechanical characteristics of hydrogels and methods employed for characterizing these properties are explored. Subsequently, the most common approaches used for tuning mechanical properties of hydrogels including but are not limited to, interpenetrating polymer networks, nanocomposites, self-assembly techniques, and co-polymerization are discussed. The performance of different techniques used for tuning biomechanical properties of hydrogels is further compared. Such techniques involve lithography techniques for replication of tissues with complex mechanical profiles; microfluidic techniques applicable for generating gradients of mechanical properties in hydrogel biomaterials for engineering complex human tissues like intervertebral discs, osteochondral tissues, blood vessels and skin layers; and electrospinning techniques for synthesis of hybrid hydrogels and highly ordered fibers with tunable mechanical and biological properties. We finally discuss future perspectives and challenges for controlling biomimetic hydrogel materials possessing proper biomechanical properties. Hydrogels biomaterials are essential constituting components of engineered tissues with the applications in regenerative medicine and drug delivery. The mechanical properties of hydrogels play crucial roles in regulating the interactions between cells and extracellular matrix and directing the cells phenotype and genotype. Despite

  15. Fabrication and mechanical characterization of 3D electrospun scaffolds for tissue engineering

    International Nuclear Information System (INIS)

    Wright, L D; Young, R T; Andric, T; Freeman, J W

    2010-01-01

    Electrospinning is a polymer processing technique that produces fibrous structures comparable to the extracellular matrix of many tissues. Electrospinning, however, has been severely limited in its tissue engineering capabilities because this technique has produced few three-dimensional structures. Sintering of electrospun materials provides a method to fabricate unique architectures and allow much larger structures to be made. Electrospun mats were sintered into strips and cylinders, and their tensile and compressive mechanical properties were measured. In addition, electrospun materials with salt pores (salt embedded within the material and then leached out) were fabricated to improve porosity of the electrospun materials for tissue engineering scaffolds. Sintered electrospun poly(d,l-lactide) and poly(l-lactide) (PDLA/PLLA) materials have higher tensile mechanical properties (modulus: 72.3 MPa, yield: 960 kPa) compared to unsintered PLLA (modulus: 40.36 MPa, yield: 675.5 kPa). Electrospun PDLA/PLLA cylinders with and without salt-leached pores had compressive moduli of 6.69 and 26.86 MPa, respectively, and compressive yields of 1.36 and 0.56 MPa, respectively. Sintering of electrospun materials is a novel technique that improves electrospinning application in tissue engineering by increasing the size and types of electrospun structures that can be fabricated.

  16. Cell-biomaterial mechanical interaction in the framework of tissue engineering: insights, computational modeling and perspectives.

    Science.gov (United States)

    Sanz-Herrera, Jose A; Reina-Romo, Esther

    2011-01-01

    Tissue engineering is an emerging field of research which combines the use of cell-seeded biomaterials both in vitro and/or in vivo with the aim of promoting new tissue formation or regeneration. In this context, how cells colonize and interact with the biomaterial is critical in order to get a functional tissue engineering product. Cell-biomaterial interaction is referred to here as the phenomenon involved in adherent cells attachment to the biomaterial surface, and their related cell functions such as growth, differentiation, migration or apoptosis. This process is inherently complex in nature involving many physico-chemical events which take place at different scales ranging from molecular to cell body (organelle) levels. Moreover, it has been demonstrated that the mechanical environment at the cell-biomaterial location may play an important role in the subsequent cell function, which remains to be elucidated. In this paper, the state-of-the-art research in the physics and mechanics of cell-biomaterial interaction is reviewed with an emphasis on focal adhesions. The paper is focused on the different models developed at different scales available to simulate certain features of cell-biomaterial interaction. A proper understanding of cell-biomaterial interaction, as well as the development of predictive models in this sense, may add some light in tissue engineering and regenerative medicine fields.

  17. Silicon subsystem mechanical engineering closeout report for the Solenoidal Detector Collaboration

    International Nuclear Information System (INIS)

    Hanlon, J.; Christensen, R.W.; Hayman, G.; Jones, D.C.; Ross, R.; Wilds, W.; Yeamans, S.; Ziock, H.J.

    1995-01-01

    The authors group at Los Alamos National Laboratory was responsible for the mechanical engineering of the silicon tracking system of the Solenoidal Detector Collaboration (SDC) experiment of the Superconducting Super Collider (SSC) project. The responsibility included the overall design of the system from the mechanical point of view, development and integration of the cooling system, which was required to remove the heat generated by the front-end electronics, assembly of the system to extremely tight tolerances, and verification that the construction and operational stability and alignment tolerances would be met. A detailed description of the concepts they developed and the work they performed can be found in a report titled ''Silicon Subsystem Mechanical Engineering Work for the Solenoidal Detector Collaboration'' which they submitted to the SSC Laboratory. In addition to the mechanical engineering work, they also performed activation, background, and shielding studies for the SSC program. Much of the work they performed was potentially useful for other future high energy physics (HEP) projects. This report describes the closeout work that was performed for the Los Alamos SDC project. Four major tasks were identified for completion: (1) integration of the semi-automated assembly station being developed and construction of a precision part to demonstrate solutions to important general assembly problems (the station was designed to build precision silicon tracker subassemblies); (2) build a state-of-the-art TV holography (TVH) system to use for detector assembly stability tests; (3) design, build, and test a water based cooling system for a full silicon shell prototype; and (4) complete and document the activation, background, and shielding studies, which is covered in a separate report

  18. Silicon subsystem mechanical engineering closeout report for the Solenoidal Detector Collaboration

    Energy Technology Data Exchange (ETDEWEB)

    Hanlon, J.; Christensen, R.W.; Hayman, G.; Jones, D.C.; Ross, R.; Wilds, W.; Yeamans, S.; Ziock, H.J.

    1995-02-01

    The authors group at Los Alamos National Laboratory was responsible for the mechanical engineering of the silicon tracking system of the Solenoidal Detector Collaboration (SDC) experiment of the Superconducting Super Collider (SSC) project. The responsibility included the overall design of the system from the mechanical point of view, development and integration of the cooling system, which was required to remove the heat generated by the front-end electronics, assembly of the system to extremely tight tolerances, and verification that the construction and operational stability and alignment tolerances would be met. A detailed description of the concepts they developed and the work they performed can be found in a report titled ``Silicon Subsystem Mechanical Engineering Work for the Solenoidal Detector Collaboration`` which they submitted to the SSC Laboratory. In addition to the mechanical engineering work, they also performed activation, background, and shielding studies for the SSC program. Much of the work they performed was potentially useful for other future high energy physics (HEP) projects. This report describes the closeout work that was performed for the Los Alamos SDC project. Four major tasks were identified for completion: (1) integration of the semi-automated assembly station being developed and construction of a precision part to demonstrate solutions to important general assembly problems (the station was designed to build precision silicon tracker subassemblies); (2) build a state-of-the-art TV holography (TVH) system to use for detector assembly stability tests; (3) design, build, and test a water based cooling system for a full silicon shell prototype; and (4) complete and document the activation, background, and shielding studies, which is covered in a separate report.

  19. Particle Engineering Via Mechanical Dry Coating in the Design of Pharmaceutical Solid Dosage Forms.

    Science.gov (United States)

    Qu, Li; Morton, David A V; Zhou, Qi Tony

    2015-01-01

    Cohesive powders are problematic in the manufacturing of pharmaceutical solid dosage forms because they exhibit poor flowability, fluidization and aerosolization. These undesirable bulk properties of cohesive powders represent a fundamental challenge in the design of efficient pharmaceutical manufacturing processes. Recently, mechanical dry coating has attracted increasing attention as it can improve the bulk properties of cohesive powders in a cheaper, simpler, safer and more environment-friendly way than the existing solvent-based counterparts. In this review, mechanical dry coating techniques are outlined and their potential applications in formulation and manufacturing of pharmaceutical solid dosage forms are discussed. Reported data from the literature have shown that mechanical dry coating holds promise for the design of superior pharmaceutical solid formulations or manufacturing processes by engineering the interfaces of cohesive powders in an efficient and economical way.

  20. Mechanical Stimulation Protocols of Human Derived Cells in Articular Cartilage Tissue Engineering - A Systematic Review.

    Science.gov (United States)

    Khozoee, Baktash; Mafi, Pouya; Mafi, Reza; Khan, Wasim S

    2017-01-01

    Mechanical stimulation is a key factor in articular cartilage generation and maintenance. Bioreactor systems have been designed and built in order to deliver specific types of mechanical stimulation. The focus has been twofold, applying a type of preconditioning in order to stimulate cell differentiation, and to simulate in vivo conditions in order to gain further insight into how cells respond to different stimulatory patterns. Due to the complex forces at work within joints, it is difficult to simulate mechanical conditions using a bioreactor. The aim of this review is to gain a deeper understanding of the complexities of mechanical stimulation protocols by comparing those employed in bioreactors in the context of tissue engineering for articular cartilage, and to consider their effects on cultured cells. Allied and Complementary Medicine 1985 to 2016, Ovid MEDLINE[R] 1946 to 2016, and Embase 1974 to 2016 were searched using key terms. Results were subject to inclusion and exclusion criteria, key findings summarised into a table and subsequently discussed. Based on this review it is overwhelmingly clear that mechanical stimulation leads to increased chondrogenic properties in the context of bioreactor articular cartilage tissue engineering using human cells. However, given the variability and lack of controlled factors between research articles, results are difficult to compare, and a standardised method of evaluating stimulation protocols proved challenging. With improved standardisation in mechanical stimulation protocol reporting, bioreactor design and building processes, along with a better understanding of joint behaviours, we hope to perform a meta-analysis on stimulation protocols and methods. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  1. An education model of a nano-positioning system for mechanical engineers

    International Nuclear Information System (INIS)

    Lee, Dong Yeon; Gweon, Dae Gab

    2006-01-01

    The increasing use of nano-positioners in a wide variety of laboratory and industrial applications has created a need for nano-mechatronics education in all engineering disciplines. The subject of nano-mechatronics is broad and interdisciplinary. This article focuses on the way nano-mechatronics is taught in department of mechanical engineering at Korea Advanced Institute of Science and Technology (KAIST). As one model of nano-positioning systems, design and experimental methodology is presented in this article. For design phase, the stiffness and resonant frequencies are found analytically and verified by using a commercial finite element analysis program. Next, for experimental phase, various tests are performed to access the performances of the designed nano-positioner, for example, sine-tracking, multi-step response and travel-range check etc. Finally, the definition of 'separation frequency' is described and some comments are discussed

  2. A systemic analysis of cheating in an undergraduate engineering mechanics course.

    Science.gov (United States)

    Bertram Gallant, Tricia; Van Den Einde, Lelli; Ouellette, Scott; Lee, Sam

    2014-03-01

    Cheating in the undergraduate classroom is not a new problem, and it is recognized as one that is endemic to the education system. This paper examines the highly normative behavior of using unauthorized assistance (e.g., a solutions manual or a friend) on an individual assignment within the context of an upper division undergraduate course in engineering mechanics. The findings indicate that there are varying levels of accepting responsibility among the students (from denial to tempered to full) and that acceptance of responsibility can lead to identification of learning and necessary behavioral changes. The findings have implications for institutions and engineering faculty, in particular the need for consistent academic integrity education and the teaching of professional integrity and ethics.

  3. Critical review on the physical and mechanical factors involved in tissue engineering of cartilage.

    Science.gov (United States)

    Gaut, Carrie; Sugaya, Kiminobu

    2015-01-01

    Articular cartilage defects often progress to osteoarthritis, which negatively impacts quality of life for millions of people worldwide and leads to high healthcare expenditures. Tissue engineering approaches to osteoarthritis have concentrated on proliferation and differentiation of stem cells by activation and suppression of signaling pathways, and by using a variety of scaffolding techniques. Recent studies indicate a key role of environmental factors in the differentiation of mesenchymal stem cells to mature cartilage-producing chondrocytes. Therapeutic approaches that consider environmental regulation could optimize chondrogenesis protocols for regeneration of articular cartilage. This review focuses on the effect of scaffold structure and composition, mechanical stress and hypoxia in modulating mesenchymal stem cell fate and the current use of these environmental factors in tissue engineering research.

  4. Reverse engineering the mechanical and molecular pathways in stem cell morphogenesis.

    Science.gov (United States)

    Lu, Kai; Gordon, Richard; Cao, Tong

    2015-03-01

    The formation of relevant biological structures poses a challenge for regenerative medicine. During embryogenesis, embryonic cells differentiate into somatic tissues and undergo morphogenesis to produce three-dimensional organs. Using stem cells, we can recapitulate this process and create biological constructs for therapeutic transplantation. However, imperfect imitation of nature sometimes results in in vitro artifacts that fail to recapitulate the function of native organs. It has been hypothesized that developing cells may self-organize into tissue-specific structures given a correct in vitro environment. This proposition is supported by the generation of neo-organoids from stem cells. We suggest that morphogenesis may be reverse engineered to uncover its interacting mechanical pathway and molecular circuitry. By harnessing the latent architecture of stem cells, novel tissue-engineering strategies may be conceptualized for generating self-organizing transplants. Copyright © 2013 John Wiley & Sons, Ltd.

  5. Mechanical engineering and design of silicon-based particle tracking devices

    International Nuclear Information System (INIS)

    Miller, W.O.; Thompson, T.C.; Gamble, M.T.; Reid, R.S.; Woloshun, K.A.; Dransfield, G.D.; Ziock, H.J.

    1990-01-01

    The Mechanical Engineering and Electronics Division of the Los Alamos National Laboratory has been investigating silicon-based particle tracking device technology as part of the Superconducting Super Collider-sponsored silicon subsystem collaboration. Structural, thermal, and materials issues have been addressed. This paper discussed detector structural integrity and stability, including detailed finite element models of the silicon chip support and predictive methods used in designing with advanced composite materials. Electronic thermal loading and efficient dissipation of such energy using heat pipe technology has been investigated. The use of materials whose coefficients of thermal expansion are engineered to match silicon or to be near zero, as appropriate, have been explored. Material analysis and test results from radiation, chemical, and static loading are compared with analytical predictions and discussed. 1 ref., 2 figs., 1 tab

  6. Education of the Mechanical Engineering Literacy by the Collaboration Learning of the Different Grade

    Science.gov (United States)

    Nakashima, Kenji; Nakaura, Shigeki; Morita, Hidetoshi; Matsuyama, Fuminori; Nishiguchi, Hiroshi; Fukuda, Takayuki

    We trained business ability of the students through the senior instructing younger student system by fourth year students in the class of the practical skill. The theme of the practical skill is the resolution and the assembling of the gasoline engine, the automatic control of the radio control car with the PLC, the learning of dynamics using Mini-Yonku and the operation of the laser cutter. For the fourth students, we can expect an effect of their ability in the future work. For the first students, we can expect an effect for them to be interested in mechanical engineering. Concerning the effects of this project, all the fourth students and teachers discussed, and the effect of the project was evaluated by a poster session. As a result, we have found that more effects than we had expected has been gained.

  7. Methodology for Developing Teaching Activities and Materials for Use in Fluid Mechanics Courses in Undergraduate Engineering Programs

    Science.gov (United States)

    Gamez-Montero, P. Javier; Raush, Gustavo; Domènech, Lluis; Castilla, Robert; García-Vílchez, Mercedes; Moreno, Hipòlit; Carbó, Albert

    2015-01-01

    "Mechanics" and "Fluids" are familiar concepts for any newly-registered engineering student. However, when combined into the term "Fluid Mechanics", students are thrust into the great unknown. The present article demonstrates the process of adaptation employed by the Fluid Mechanics course in the undergraduate…

  8. The effects of matrix inhomogeneities on the cellular mechanical environment in tissue-engineered cartilage : an in silico investigation

    NARCIS (Netherlands)

    Khoshgoftar, M.; Wilson, W.; Ito, K.; Donkelaar, van C.C.

    2014-01-01

    Mechanical stimulation during cartilage tissue-engineering (TE) enhances extracellular matrix (ECM) synthesis and thereby improves the mechanical properties of TE cartilage. Generally, these mechanical stimuli are of a fixed magnitude. However, as a result of ECM synthesis and spatial variations

  9. Biphasic Finite Element Modeling Reconciles Mechanical Properties of Tissue-Engineered Cartilage Constructs Across Testing Platforms.

    Science.gov (United States)

    Meloni, Gregory R; Fisher, Matthew B; Stoeckl, Brendan D; Dodge, George R; Mauck, Robert L

    2017-07-01

    Cartilage tissue engineering is emerging as a promising treatment for osteoarthritis, and the field has progressed toward utilizing large animal models for proof of concept and preclinical studies. Mechanical testing of the regenerative tissue is an essential outcome for functional evaluation. However, testing modalities and constitutive frameworks used to evaluate in vitro grown samples differ substantially from those used to evaluate in vivo derived samples. To address this, we developed finite element (FE) models (using FEBio) of unconfined compression and indentation testing, modalities commonly used for such samples. We determined the model sensitivity to tissue radius and subchondral bone modulus, as well as its ability to estimate material parameters using the built-in parameter optimization tool in FEBio. We then sequentially tested agarose gels of 4%, 6%, 8%, and 10% weight/weight using a custom indentation platform, followed by unconfined compression. Similarly, we evaluated the ability of the model to generate material parameters for living constructs by evaluating engineered cartilage. Juvenile bovine mesenchymal stem cells were seeded (2 × 10 7 cells/mL) in 1% weight/volume hyaluronic acid hydrogels and cultured in a chondrogenic medium for 3, 6, and 9 weeks. Samples were planed and tested sequentially in indentation and unconfined compression. The model successfully completed parameter optimization routines for each testing modality for both acellular and cell-based constructs. Traditional outcome measures and the FE-derived outcomes showed significant changes in material properties during the maturation of engineered cartilage tissue, capturing dynamic changes in functional tissue mechanics. These outcomes were significantly correlated with one another, establishing this FE modeling approach as a singular method for the evaluation of functional engineered and native tissue regeneration, both in vitro and in vivo.

  10. Study of mechanical properties and fracture mechanisms of synthetic fibers nylon-and-polyester type, used in engineering products

    International Nuclear Information System (INIS)

    Cardoso, Sergio Gomes

    2009-01-01

    Fibers are groups formed by molecular-chain-oriented filaments. Fibers play a fundamental role in human being's daily life and they can be found in several forms and geometries, such as filaments, yarns, beams, rope, fabric, composite, coatings, others. They are used in various segments such as civil, mechanical, electrical, electronics, military, naval, nautical, aviation, health, medicine, environment, communications, safety, space, others. Fibers are divided into two distinct classes: natural and chemical ones, which cover synthetic and man-made sub-classes. They can be produced from several materials, such as wool, cotton, rayon, flax, silk, rock, nylon, polyester, polyethylene, poly-propylene, aramid, glass, carbon, steel, ceramic, others. Globally, the participation of chemical fibers corresponds to approximately 59,9%, and the synthetic fiber polyester, the most used one, represents approximately 63% of the world market. Vital needs have led to the development of multi-function fibers and the focus has changed in the last 10 years with the use of nano technology for environmental responsibility and smart fibers. The study of mechanical properties and fracture mechanisms of fibers is of great relevance for characterization and understanding of causes as consequence of failures. For such reason, it was selected technical fabrics made of high performance synthetic fiber nylon-and-polyester type, used in engineered products such as tires, belts, hoses and pneumatic springs, which have been analyzed in each processing phase. Fiber samples were extracted after each processing phase to be analyzed, by traction destructive tests and scanning electron microscopy. The results of analysis of mechanical properties showed loss of resistance to temperature and multi axial stress during fiber processing phase. Through microscopy tests, it was possible to find contamination, surface stains, plastic deformations, scaling, variations in the fracture faces of the filaments and

  11. Engineering the Mechanical Properties of Polymer Networks with Precise Doping of Primary Defects.

    Science.gov (United States)

    Chan, Doreen; Ding, Yichuan; Dauskardt, Reinhold H; Appel, Eric A

    2017-12-06

    Polymer networks are extensively utilized across numerous applications ranging from commodity superabsorbent polymers and coatings to high-performance microelectronics and biomaterials. For many applications, desirable properties are known; however, achieving them has been challenging. Additionally, the accurate prediction of elastic modulus has been a long-standing difficulty owing to the presence of loops. By tuning the prepolymer formulation through precise doping of monomers, specific primary network defects can be programmed into an elastomeric scaffold, without alteration of their resulting chemistry. The addition of these monomers that respond mechanically as primary defects is used both to understand their impact on the resulting mechanical properties of the materials and as a method to engineer the mechanical properties. Indeed, these materials exhibit identical bulk and surface chemistry, yet vastly different mechanical properties. Further, we have adapted the real elastic network theory (RENT) to the case of primary defects in the absence of loops, thus providing new insights into the mechanism for material strength and failure in polymer networks arising from primary network defects, and to accurately predict the elastic modulus of the polymer system. The versatility of the approach we describe and the fundamental knowledge gained from this study can lead to new advancements in the development of novel materials with precisely defined and predictable chemical, physical, and mechanical properties.

  12. 77 FR 11140 - Availability of the Draft Supplementary Risk Assessment for the Boston University (BU) National...

    Science.gov (United States)

    2012-02-24

    ... analysis include the Boston University Medical Campus (BUMC) BioSquare Research Park, Boston, where the... construction grant to Boston University Medical Campus to partly fund the design and construction of one of two..., bioethics, biodefense, biosafety, and infectious disease modeling. The NIH has also sought guidance from the...

  13. The Center for Social Innovation at Boston College.

    Science.gov (United States)

    Berzin, Stephanie Cosner; Dearing, Tiziana; Mathews, Olivia; Choi, Yeon Jin; Pitt-Catsouphes, Marcie

    2018-01-01

    Established in 2011, the Center for Social Innovation at Boston College has focused on fostering "effective, sustainable social innovations that enhance social justice." the Center is committed to building research evidence that is used for changing practice and works to disseminate findings through a three-channel approach: traditional research publications, convening of practitioners, and through use of media outlets.

  14. 33 CFR 110.30 - Boston Harbor, Mass.

    Science.gov (United States)

    2010-07-01

    ... Yacht Club, South Boston. Northerly of a line bearing 96° from the stack of the heating plant of the... Yacht Club property. (b) Dorchester Bay, in vicinity of Savin Hill Yacht Club. Northerly of a line... vicinity of Dorchester Yacht Club. Eastward of a line bearing 21° from the stack located a short distance...

  15. The Closing of the Classified Catalog at Boston University

    Science.gov (United States)

    Hazen, Margaret Hindle

    1974-01-01

    Although the classified catalog at Boston University libraries has been a useful research tool, it has proven too expensive to keep current. The library has converted to a traditional alphabetic subject catalog and will recieve catalog cards from the Ohio College Library Center through the New England Library Network. (Author/LS)

  16. Early weaning might reduce the psychological strain of Boston bracing

    DEFF Research Database (Denmark)

    Andersen, Mikkel Ø; Andersen, Gert Rahbek; Thomsen, Karsten

    2002-01-01

    From 1983 to 1990 a total of 136 patients with adolescent idiopathic scoliosis were treated with the Boston brace. With the aim of examining the social and psychological impact of the brace treatment all patients received a questionnaire at an average of 3.5 years after termination of the treatment...

  17. The Emerald Necklace: Boston's Green Connection. Teaching with Historic Places.

    Science.gov (United States)

    Marsh, Lisa; Snow, Pamela

    In 1870, Boston, Massachusetts, was an overcrowded, noisy, and dirty city. Concerned with the health and happiness of Bostonians restricted to these unhealthy surroundings, the city hired Frederick Law Olmsted to design a park system. The series of parks he designed over the next several years is known as the Emerald Necklace. From lovely…

  18. Charter, Private, and Public Schools Work Together in Boston

    Science.gov (United States)

    Lam, Diana

    2014-01-01

    A public, Catholic, and charter school in Boston all work together to share their strengths and learn from each other in an effort to deliver the best education for all of their students. The arrangement is called the School Performance Partnership, and it is a grantee of the Bill and Melinda Gates Foundation.

  19. Matrix production and organization by endothelial colony forming cells in mechanically strained engineered tissue constructs.

    Directory of Open Access Journals (Sweden)

    Nicky de Jonge

    Full Text Available AIMS: Tissue engineering is an innovative method to restore cardiovascular tissue function by implanting either an in vitro cultured tissue or a degradable, mechanically functional scaffold that gradually transforms into a living neo-tissue by recruiting tissue forming cells at the site of implantation. Circulating endothelial colony forming cells (ECFCs are capable of differentiating into endothelial cells as well as a mesenchymal ECM-producing phenotype, undergoing Endothelial-to-Mesenchymal-transition (EndoMT. We investigated the potential of ECFCs to produce and organize ECM under the influence of static and cyclic mechanical strain, as well as stimulation with transforming growth factor β1 (TGFβ1. METHODS AND RESULTS: A fibrin-based 3D tissue model was used to simulate neo-tissue formation. Extracellular matrix organization was monitored using confocal laser-scanning microscopy. ECFCs produced collagen and also elastin, but did not form an organized matrix, except when cultured with TGFβ1 under static strain. Here, collagen was aligned more parallel to the strain direction, similar to Human Vena Saphena Cell-seeded controls. Priming ECFC with TGFβ1 before exposing them to strain led to more homogenous matrix production. CONCLUSIONS: Biochemical and mechanical cues can induce extracellular matrix formation by ECFCs in tissue models that mimic early tissue formation. Our findings suggest that priming with bioactives may be required to optimize neo-tissue development with ECFCs and has important consequences for the timing of stimuli applied to scaffold designs for both in vitro and in situ cardiovascular tissue engineering. The results obtained with ECFCs differ from those obtained with other cell sources, such as vena saphena-derived myofibroblasts, underlining the need for experimental models like ours to test novel cell sources for cardiovascular tissue engineering.

  20. Multiaxial mechanical response and constitutive modeling of esophageal tissues: Impact on esophageal tissue engineering.

    Science.gov (United States)

    Sommer, Gerhard; Schriefl, Andreas; Zeindlinger, Georg; Katzensteiner, Andreas; Ainödhofer, Herwig; Saxena, Amulya; Holzapfel, Gerhard A

    2013-12-01

    Congenital defects of the esophagus are relatively frequent, with 1 out of 2500 babies suffering from such a defect. A new method of treatment by implanting tissue engineered esophagi into newborns is currently being developed and tested using ovine esophagi. For the reconstruction of the biological function of native tissues with engineered esophagi, their cellular structure as well as their mechanical properties must be considered. Since very limited mechanical and structural data for the esophagus are available, the aim of this study was to investigate the multiaxial mechanical behavior of the ovine esophagus and the underlying microstructure. Therefore, uniaxial tensile, biaxial tensile and extension-inflation tests on esophagi were performed. The underlying microstructure was examined in stained histological sections through standard optical microscopy techniques. Moreover, the uniaxial ultimate tensile strength and residual deformations of the tissue were determined. Both the mucosa-submucosa and the muscle layers showed nonlinear and anisotropic mechanical behavior during uniaxial, biaxial and inflation testing. Cyclical inflation of the intact esophageal tube caused marked softening of the passive esophagi in the circumferential direction. The rupture strength of the mucosa-submucosa layer was much higher than that of the muscle layer. Overall, the ovine esophagus showed a heterogeneous and anisotropic behavior with different mechanical properties for the individual layers. The intact and layer-specific multiaxial properties were characterized using a well-known three-dimensional microstructurally based strain-energy function. This novel and complete set of data serves the basis for a better understanding of tissue remodeling in diseased esophagi and can be used to perform computer simulations of surgical interventions or medical-device applications. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  1. Application of SolidWorks Plastic in the Training in Mechanical Engineering

    Directory of Open Access Journals (Sweden)

    Maria Ivanova Bakalova

    2017-12-01

    Full Text Available Abstract. In this article is presented an example of the application of SolidWorks the training in mechanical engineering. The main features of the design of the parts intended for injection molding are mentioned. SolidWorks allows all these recommendations to be implemented when creating the details. The text explains the simulation settings that are made in SolidWorks Plastics when simulating injection molding. Through a specific example referred to how to make an analysis of the results obtained.

  2. Cloning Nacre's 3D Interlocking Skeleton in Engineering Composites to Achieve Exceptional Mechanical Properties.

    Science.gov (United States)

    Zhao, Hewei; Yue, Yonghai; Guo, Lin; Wu, Juntao; Zhang, Youwei; Li, Xiaodong; Mao, Shengcheng; Han, Xiaodong

    2016-07-01

    Ceramic/polymer composite equipped with 3D interlocking skeleton (3D IL) is developed through a simple freeze-casting method, exhibiting exceptionally light weight, high strength, toughness, and shock resistance. Long-range crack energy dissipation enabled by 3D interlocking structure is considered as the primary reinforcing mechanism for such superior properties. The smart composite design strategy should hold a place in developing future structural engineering materials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Biaxial Stretch Improves Elastic Fiber Maturation, Collagen Arrangement, and Mechanical Properties in Engineered Arteries.

    Science.gov (United States)

    Huang, Angela H; Balestrini, Jenna L; Udelsman, Brooks V; Zhou, Kevin C; Zhao, Liping; Ferruzzi, Jacopo; Starcher, Barry C; Levene, Michael J; Humphrey, Jay D; Niklason, Laura E

    2016-06-01

    Tissue-engineered blood vessels (TEVs) are typically produced using the pulsatile, uniaxial circumferential stretch to mechanically condition and strengthen the arterial grafts. Despite improvements in the mechanical integrity of TEVs after uniaxial conditioning, these tissues fail to achieve critical properties of native arteries such as matrix content, collagen fiber orientation, and mechanical strength. As a result, uniaxially loaded TEVs can result in mechanical failure, thrombus, or stenosis on implantation. In planar tissue equivalents such as artificial skin, biaxial loading has been shown to improve matrix production and mechanical properties. To date however, multiaxial loading has not been examined as a means to improve mechanical and biochemical properties of TEVs during culture. Therefore, we developed a novel bioreactor that utilizes both circumferential and axial stretch that more closely simulates loading conditions in native arteries, and we examined the suture strength, matrix production, fiber orientation, and cell proliferation. After 3 months of biaxial loading, TEVs developed a formation of mature elastic fibers that consisted of elastin cores and microfibril sheaths. Furthermore, the distinctive features of collagen undulation and crimp in the biaxial TEVs were absent in both uniaxial and static TEVs. Relative to the uniaxially loaded TEVs, tissues that underwent biaxial loading remodeled and realigned collagen fibers toward a more physiologic, native-like organization. The biaxial TEVs also showed increased mechanical strength (suture retention load of 303 ± 14.53 g, with a wall thickness of 0.76 ± 0.028 mm) and increased compliance. The increase in compliance was due to combinatorial effects of mature elastic fibers, undulated collagen fibers, and collagen matrix orientation. In conclusion, biaxial stretching is a potential means to regenerate TEVs with improved matrix production, collagen organization, and mechanical

  4. Program Guide for Diesel Engine Mechanics 8742000 (IN47.060500) and Heavy Duty Truck and Bus Mechanics DIM0991 (IN47.060501).

    Science.gov (United States)

    University of South Florida, Tampa. Coll. of Education.

    This competency-based program guide provides course content information and procedures for secondary schools, postsecondary vocational schools, and community colleges in Florida that conduct programs in diesel engine mechanics and heavy duty truck and bus mechanics. The first section is on legal authority, which applies to all vocational education…

  5. Molecular mechanism of hypoxia-induced chondrogenesis and its application in in vivo cartilage tissue engineering.

    Science.gov (United States)

    Duval, Elise; Baugé, Catherine; Andriamanalijaona, Rina; Bénateau, Hervé; Leclercq, Sylvain; Dutoit, Soizic; Poulain, Laurent; Galéra, Philippe; Boumédiene, Karim

    2012-09-01

    Cartilage engineering is one of the most challenging issue in regenerative medicine, due to its limited self-ability to repair. Here, we assessed engineering of cartilage tissue starting from human bone marrow (hBM) stem cells under hypoxic environment and delineated the mechanism whereby chondrogenesis could be conducted without addition of exogenous growth factors. hBM stem cells were cultured in alginate beads and chondrogenesis was monitored by chondrocyte phenotypic markers. Activities and roles of Sox and HIF-1α transcription factors were investigated with complementary approaches of gain and loss of function and provided evidences that HIF-1α is essential for hypoxic induction of chondrogenesis. Thereafter, hBM cells and human articular chondrocytes (HAC) underwent chondrogenesis by 3D and hypoxic culture for 7 days or by ectopic expression of HIF-1α. After subcutaneous implantation of 3 weeks into athymic mice, tissue analysis showed that hypoxia or HIF-1α overexpression is effective and sufficient to induce chondrocyte phenotype in hBM cells, without use of exogenous growth factors. Therefore, this study brings interesting data for a simple and affordable system in biotechnology of cartilage engineering. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Assessment on mechanical effect of engineering barrier system to fault movement. Research document

    International Nuclear Information System (INIS)

    Hirai, Takashi; Tanai, Kenji; Takaji, Kazuhiko; Ohnuma, Satoshi

    2003-03-01

    The objective of this report is to clarify mechanical effect of engineering barrier system to the unavoidable fault movement. From the basic policy of the second progress report by JNC, natural phenomenon which affect strongly to the geological disposal system should be avoided. However, small faults as sliprate ''C'' far from principal fault zone, are difficult to be found out completely. Therefore, it is important to evaluate the influence of these fault movements and to clarify stability and safety of the engineered barrier system. Accordingly, the effect of a rock displacement across a deposition holl was considered and the midium scale test was carried out. Then midium scale test was simulated by Finit Element Method in which the constitutive model of Tresca was adopted to analyze elastoplastic behavior of buffer material. From the result of the midium scale test and the analysis, it was realized that the buffer material diminish shear stress acting on the overpack. Further analytical study was conducted to evaluate the real scale engineered barrier system designed in the second progress report by JNC. From the study, it was appeared that stress in buffer corresponded to the stress calculated for the midium scale test model. Consequently, it was obvious that rock displacement, 80% of buffer didn't affect overpack if velocity of fault movement was under 10 cm/sec. (author)

  7. Combining mechanical foaming and thermally induced phase separation to generate chitosan scaffolds for soft tissue engineering.

    Science.gov (United States)

    Biswas, D P; Tran, P A; Tallon, C; O'Connor, A J

    2017-02-01

    In this paper, a novel foaming methodology consisting of turbulent mixing and thermally induced phase separation (TIPS) was used to generate scaffolds for tissue engineering. Air bubbles were mechanically introduced into a chitosan solution which forms the continuous polymer/liquid phase in the foam created. The air bubbles entrained in the foam act as a template for the macroporous architecture of the final scaffolds. Wet foams were crosslinked via glutaraldehyde and frozen at -20 °C to induce TIPS in order to limit film drainage, bubble coalescence and Ostwald ripening. The effects of production parameters, including mixing speed, surfactant concentration and chitosan concentration, on foaming are explored. Using this method, hydrogel scaffolds were successfully produced with up to 80% porosity, average pore sizes of 120 μm and readily tuneable compressive modulus in the range of 2.6 to 25 kPa relevant to soft tissue engineering applications. These scaffolds supported 3T3 fibroblast cell proliferation and penetration and therefore show significant potential for application in soft tissue engineering.

  8. Effects of Structural Deformations of the Crank-Slider Mechanism on the Estimation of the Instantaneous Engine Friction Torque

    Science.gov (United States)

    CHALHOUB, N. G.; NEHME, H.; HENEIN, N. A.; BRYZIK, W.

    1999-07-01

    The focus on the current study is to assess the effects of structural deformations of the crankshaft/connecting-rod/piston mechanism on the computation of the instantaneous engine friction torque. This study is performed in a fully controlled environment in order to isolate the effects of structural deformations from those of measurement errors or noise interference. Therefore, a detailed model, accounting for the rigid and flexible motions of the crank-slider mechanism and including engine component friction formulations, is considered in this study. The model is used as a test bed to generate the engine friction torque,Tfa, and to predict the rigid and flexible motions of the system in response to the cylinder gas pressure. The torsional vibrations and the rigid body angular velocity of the crankshaft, as predicted by the detailed model of the crank-slider mechanism, are used along with the engine load torque and the cylinder gas pressure in the (P-ω) method to estimate the engine friction torque,Tfe. This method is well suited for the purpose of this study because its formulation is based on the rigid body model of the crank-slider mechanism. The digital simulation results demonstrate that the exclusion of the structural deformations of the crank-slider mechanism from the formulation of the (P-ω) method leads to an overestimation of the engine friction torque near the top-dead-center (TDC) position of the piston under firing conditions. Moreover, for the remainder of the engine cycle, the estimated friction torque exhibits large oscillations and takes on positive numerical values as if it is inducing energy into the system. Thus, the adverse effects of structural deformations of the crank-slider mechanism on the estimation of the engine friction torque greatly differ in their nature from one phase of the engine cycle to another.

  9. COBEM 99: Proceedings of the 15. Brazilian congress on mechanical engineering

    International Nuclear Information System (INIS)

    1999-01-01

    The Brazilian Congress on Mechanical Engineering is the main event promoted by the Brazilian Society of Mechanical Sciences and happens biannually. In the congress people involved in industrial, research and teaching activities are able to meet and discuss or present, in technical sessions and exhibitions, recent technological and scientific contributions to this area and related activities. The 15. edition of the COBEM, due to 99, took place in Aguas de Lindoia, Sao Paulo State. Theoretical and experimental papers are presented approaching the following area and subjects: petroleum industry, equipment and products, gas and wind turbines, hydroelectric power plants and equipment, environmental subjects, computerized analysis, heat transfer, fluid flow, thermal machines, porous media, nuclear energy, solar energy, refrigeration, energy sources, consumption and conservation

  10. Grain Boundary Engineering the Mechanical Properties of Allvac 718Plus(Trademark) Superalloy

    Science.gov (United States)

    Gabb, Timothy P.; Telesman, Jack; Garg, Anita; Lin, Peter; Provenzano, virgil; Heard, Robert; Miller, Herbert M.

    2010-01-01

    Grain Boundary Engineering can enhance the population of structurally-ordered "low S" Coincidence Site Lattice (CSL) grain boundaries in the microstructure. In some alloys, these "special" grain boundaries have been reported to improve overall resistance to corrosion, oxidation, and creep resistance. Such improvements could be quite beneficial for superalloys, especially in conditions which encourage damage and cracking at grain boundaries. Therefore, the effects of GBE processing on high-temperature mechanical properties of the cast and wrought superalloy Allvac 718Plus (Allvac ATI) were screened. Bar sections were subjected to varied GBE processing, and then consistently heat treated, machined, and tested at 650 C. Creep, tensile stress relaxation, and dwell fatigue crack growth tests were performed. The influences of GBE processing on microstructure, mechanical properties, and associated failure modes are discussed.

  11. A Space Cam Mechanism for Power Transmission of an Opposite-cylinder Piston Engine

    Directory of Open Access Journals (Sweden)

    Zhang Haoyue

    2015-01-01

    Full Text Available For the purpose of improving the engine’s power density, we put forward a new type of power transmission mechanism which is used for opposed-cylinder engine. The gas pressure acts on the cam through the piston and push rod, and the spindle rotation of external is driven by the cam. The design of spatial cam work surface is completed by using the enveloping theory of a family of space curves, the force between roller and cam is analyzed using dynamic analysis software. Under the condition of equal number, size and stroke of piston, the new one with larger power density is more compact in structure than the traditional power transmission mechanism, and the reaction force on either side of the main shaft and the acting force between pistons and cylinders are smaller than those in traditional one, which prolongs the service life of the pistons.

  12. Taking Stock: Five Years of Structural Change in Boston's Public Schools. A Boston Indicators Project Special Report

    Science.gov (United States)

    McEnroe, Ted

    2014-01-01

    While structural reform has certainly inspired change in Boston's public schools, its true value is best measured by examining the impact those changes have had on students. Seen through the lens of student performance over the past five years there is ample suggestion that these structural changes have been more than just window dressing--they…

  13. The Path Forward: School Autonomy and Its Implications for the Future of Boston's Public Schools. Understanding Boston

    Science.gov (United States)

    French, Dan; Hawley Miles, Karen; Nathan, Linda

    2014-01-01

    Boston Public Schools is at a crossroads. Nearly one-third of the system's schools operate under one of several "autonomy" structures, where school leaders have increased flexibility regarding staffing and other resources, and choice data indicate parents are far more likely to prefer these schools over so-called "traditional"…

  14. Mechanical enhancement and in vitro biocompatibility of nanofibrous collagen-chitosan scaffolds for tissue engineering.

    Science.gov (United States)

    Zou, Fengjuan; Li, Runrun; Jiang, Jianjun; Mo, Xiumei; Gu, Guofeng; Guo, Zhongwu; Chen, Zonggang

    2017-12-01

    The collagen-chitosan complex with a three-dimensional nanofiber structure was fabricated to mimic native ECM for tissue repair and biomedical applications. Though the three-dimensional hierarchical fibrous structures of collagen-chitosan composites could provide more adequate stimulus to facilitate cell adhesion, migrate and proliferation, and thus have the potential as tissue engineering scaffolding, there are still limitations in their applications due to the insufficient mechanical properties of natural materials. Because poly (vinyl alcohol) (PVA) and thermoplastic polyurethane (TPU) as biocompatible synthetic polymers can offer excellent mechanical properties, they were introduced into the collagen-chitosan composites to fabricate the mixed collagen/chitosan/PVA fibers and a sandwich structure (collagen/chitosan-TPU-collagen/chitosan) of nanofiber in order to enhance the mechanical properties of the nanofibrous collagen-chitosan scaffold. The results showed that the tensile behavior of materials was enhanced to different degrees with the difference of collagen content in the fibers. Besides the Young's modulus had no obvious changes, both the break strength and the break elongation of materials were heightened after reinforced by PVA. For the collagen-chitosan nanofiber reinforced by TPU, both the break strength and the Young's modulus of materials were heightened in different degrees with the variety of collagen content in the fibers despite the decrease of the break elongation of materials to some extent. In vitro cell test demonstrated that the materials could provide adequate environment for cell adhesion and proliferation. All these indicated that the reinforced collagen-chitosan nanofiber could be as potential scaffold for tissue engineering according to the different mechanical requirements in clinic.

  15. Possible Mechanisms for Turbofan Engine Ice Crystal Icing at High Altitude

    Science.gov (United States)

    Tsao, Jen-Ching; Struk, Peter M.; Oliver, Michael J.

    2016-01-01

    A thermodynamic model is presented to describe possible mechanisms of ice formation on unheated surfaces inside a turbofan engine compression system from fully glaciated ice crystal clouds often formed at high altitude near deep convective weather systems. It is shown from the analysis that generally there could be two distinct types of ice formation: (1) when the "surface freezing fraction" is in the range of 0 to 1, dominated by the freezing of water melt from fully or partially melted ice crystals, the ice structure is formed from accretion with strong adhesion to the surface, and (2) when the "surface melting fraction" is the range of 0 to 1, dominated by the further melting of ice crystals, the ice structure is formed from accumulation of un-melted ice crystals with relatively weak bonding to the surface. The model captures important qualitative trends of the fundamental ice-crystal icing phenomenon reported earlier (Refs. 1 and 2) from the research collaboration work by NASA and the National Research Council (NRC) of Canada. Further, preliminary analysis of test data from the 2013 full scale turbofan engine ice crystal icing test (Ref. 3) conducted in the NASA Glenn Propulsion Systems Laboratory (PSL) has also suggested that (1) both types of ice formation occurred during the test, and (2) the model has captured some important qualitative trend of turning on (or off) the ice crystal ice formation process in the tested engine low pressure compressor (LPC) targeted area under different icing conditions that ultimately would lead to (or suppress) an engine core roll back (RB) event.

  16. Implementation of Simulation Based-Concept Attainment Method to Increase Interest Learning of Engineering Mechanics Topic

    Science.gov (United States)

    Sultan, A. Z.; Hamzah, N.; Rusdi, M.

    2018-01-01

    The implementation of concept attainment method based on simulation was used to increase student’s interest in the subjects Engineering of Mechanics in second semester of academic year 2016/2017 in Manufacturing Engineering Program, Department of Mechanical PNUP. The result of the implementation of this learning method shows that there is an increase in the students’ learning interest towards the lecture material which is summarized in the form of interactive simulation CDs and teaching materials in the form of printed books and electronic books. From the implementation of achievement method of this simulation based concept, it is noted that the increase of student participation in the presentation and discussion as well as the deposit of individual assignment of significant student. With the implementation of this method of learning the average student participation reached 89%, which before the application of this learning method only reaches an average of 76%. And also with previous learning method, for exam achievement of A-grade under 5% and D-grade above 8%. After the implementation of the new learning method (simulation based-concept attainment method) the achievement of Agrade has reached more than 30% and D-grade below 1%.

  17. Virtual reality as a new trend in mechanical and electrical engineering education

    Directory of Open Access Journals (Sweden)

    Kamińska Dorota

    2017-12-01

    Full Text Available In their daily practice, academics frequently face lack of access to modern equipment and devices, which are currently in use on the market. Moreover, many students have problems with understanding issues connected to mechanical and electrical engineering due to the complexity, necessity of abstract thinking and the fact that those concepts are not fully tangible. Many studies indicate that virtual reality can be successfully used as a training tool in various domains, such as development, health-care, the military or school education. In this paper, an interactive training strategy for mechanical and electrical engineering education shall be proposed. The prototype of the software consists of a simple interface, meaning it is easy for comprehension and use. Additionally, the main part of the prototype allows the user to virtually manipulate a 3D object that should be analyzed and studied. Initial studies indicate that the use of virtual reality can contribute to improving the quality and efficiency of higher education, as well as qualifications, competencies and the skills of graduates, and increase their competitiveness in the labour market.

  18. Mechanical Behaviour of Inconel 718 Thin-Walled Laser Welded Components for Aircraft Engines

    Directory of Open Access Journals (Sweden)

    Enrico Lertora

    2014-01-01

    Full Text Available Nickel alloys are very important in many aerospace applications, especially to manufacture gas turbines and aero engine components, where high strength and temperature resistance are necessary. These kinds of alloys have to be welded with high energy density processes, in order to preserve their high mechanical properties. In this work, CO2 laser overlap joints between Inconel 718 sheets of limited thickness in the absence of postweld heat treatment were made. The main application of this kind of joint is the manufacturing of a helicopter engine component. In particular the aim was to obtain a specific cross section geometry, necessary to overcome the mechanical stresses found in these working conditions without failure. Static and dynamic tests were performed to assess the welds and the parent material fatigue life behaviour. Furthermore, the life trend was identified. This research pointed out that a full joint shape control is possible by choosing proper welding parameters and that the laser beam process allows the maintenance of high tensile strength and ductility of Inconel 718 but caused many liquation microcracks in the heat affected zone (HAZ. In spite of these microcracks, the fatigue behaviour of the overlap welds complies with the technical specifications required by the application.

  19. Fabrication and mechanical characterization of a polyvinyl alcohol sponge for tissue engineering applications.

    Science.gov (United States)

    Karimi, A; Navidbakhsh, M; Faghihi, S

    2014-05-01

    Polyvinyl alcohol (PVA) sponges are widely used for clinical applications, including ophthalmic surgical treatments, wound healing and tissue engineering. There is, however, a lack of sufficient data on the mechanical properties of PVA sponges. In this study, a biomechanical method is used to characterize the elastic modulus, maximum stress and strain as well as the swelling ratio of a fabricated PVA sponge (P-sponge) and it is compared with two commercially available PVA sponges (CENEFOM and EYETEC). The results indicate that the elastic modulus of the P-sponge is 5.32% and 13.45% lower than that of the CENEFOM and EYETEC sponges, while it bears 4.11% more and 10.37% less stress compared to the CENEFOM and EYETEC sponges, respectively. The P-sponge shows a maximum strain of 32% more than the EYETEC sponge as well as a 26.78% higher swelling ratio, which is a significantly higher absorbency compared to the CENEFOM. It is believed that the results of this study would help for a better understanding of the extension, rupture and swelling mechanism of PVA sponges, which could lead to crucial improvement in the design and application of PVA-based materials in ophthalmic and plastic surgeries as well as wound healing and tissue engineering.

  20. Improving the mechanical properties of collagen-based membranes using silk fibroin for corneal tissue engineering.

    Science.gov (United States)

    Long, Kai; Liu, Yang; Li, Weichang; Wang, Lin; Liu, Sa; Wang, Yingjun; Wang, Zhichong; Ren, Li

    2015-03-01

    Although collagen with outstanding biocompatibility has promising application in corneal tissue engineering, the mechanical properties of collagen-based scaffolds, especially suture retention strength, must be further improved to satisfy the requirements of clinical applications. This article describes a toughness reinforced collagen-based membrane using silk fibroin. The collagen-silk fibroin membranes based on collagen [silk fibroin (w/w) ratios of 100:5, 100:10, and 100:20] were prepared by using silk fibroin and cross-linking by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide. These membranes were analyzed by scanning electron microscopy and their optical property, and NaCl and tryptophan diffusivity had been tested. The water content was found to be dependent on the content of silk fibroin, and CS10 membrane (loading 10 wt % of silk fibroin) performed the optimal mechanical properties. Also the suture experiments have proved CS10 has high suture retention strength, which can be sutured in rabbit eyes integrally. Moreover, the composite membrane proved good biocompatibility for the proliferation of human corneal epithelial cells in vitro. Lamellar keratoplasty shows that CS10 membrane promoted complete epithelialization in 35 ± 5 days, and their transparency is restored quickly in the first month. Corneal rejection reaction, neovascularization, and keratoconus are not observed. The composite films show potential for use in the field of corneal tissue engineering. © 2014 Wiley Periodicals, Inc.

  1. Engineering cell wall synthesis mechanism for enhanced PHB accumulation in E. coli.

    Science.gov (United States)

    Zhang, Xing-Chen; Guo, Yingying; Liu, Xu; Chen, Xin-Guang; Wu, Qiong; Chen, Guo-Qiang

    2018-01-01

    The rigidity of bacterial cell walls synthesized by a complicated pathway limit the cell shapes as coccus, bar or ellipse or even fibers. A less rigid bacterium could be beneficial for intracellular accumulation of poly-3-hydroxybutyrate (PHB) as granular inclusion bodies. To understand how cell rigidity affects PHB accumulation, E. coli cell wall synthesis pathway was reinforced and weakened, respectively. Cell rigidity was achieved by thickening the cell walls via insertion of a constitutive gltA (encoding citrate synthase) promoter in front of a series of cell wall synthesis genes on the chromosome of several E. coli derivatives, resulting in 1.32-1.60 folds increase of Young's modulus in mechanical strength for longer E. coli cells over-expressing fission ring FtsZ protein inhibiting gene sulA. Cell rigidity was weakened by down regulating expressions of ten genes in the cell wall synthesis pathway using CRISPRi, leading to elastic cells with more spaces for PHB accumulation. The regulation on cell wall synthesis changes the cell rigidity: E. coli with thickened cell walls accumulated only 25% PHB while cell wall weakened E. coli produced 93% PHB. Manipulation on cell wall synthesis mechanism adds another possibility to morphology engineering of microorganisms. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  2. Virtual reality as a new trend in mechanical and electrical engineering education

    Science.gov (United States)

    Kamińska, Dorota; Sapiński, Tomasz; Aitken, Nicola; Rocca, Andreas Della; Barańska, Maja; Wietsma, Remco

    2017-12-01

    In their daily practice, academics frequently face lack of access to modern equipment and devices, which are currently in use on the market. Moreover, many students have problems with understanding issues connected to mechanical and electrical engineering due to the complexity, necessity of abstract thinking and the fact that those concepts are not fully tangible. Many studies indicate that virtual reality can be successfully used as a training tool in various domains, such as development, health-care, the military or school education. In this paper, an interactive training strategy for mechanical and electrical engineering education shall be proposed. The prototype of the software consists of a simple interface, meaning it is easy for comprehension and use. Additionally, the main part of the prototype allows the user to virtually manipulate a 3D object that should be analyzed and studied. Initial studies indicate that the use of virtual reality can contribute to improving the quality and efficiency of higher education, as well as qualifications, competencies and the skills of graduates, and increase their competitiveness in the labour market.

  3. Viscoelastic behaviour of hydrogel-based composites for tissue engineering under mechanical load.

    Science.gov (United States)

    Kocen, Rok; Gasik, Michael; Gantar, Ana; Novak, Saša

    2017-03-06

    Along with biocompatibility, bioinductivity and appropriate biodegradation, mechanical properties are also of crucial importance for tissue engineering scaffolds. Hydrogels, such as gellan gum (GG), are usually soft materials, which may benefit from the incorporation of inorganic particles, e.g. bioactive glass, not only due to the acquired bioactivity, but also due to improved mechanical properties. They exhibit complex viscoelastic properties, which can be evaluated in various ways. In this work, to reliably evaluate the effect of the bioactive glass (BAG) addition on viscoelastic properties of the composite hydrogel, we employed and compared the three most commonly used techniques, analyzing their advantages and limitations: monotonic uniaxial unconfined compression, small amplitude oscillatory shear (SAOS) rheology and dynamic mechanical analysis (DMA). Creep and small amplitude dynamic strain-controlled tests in DMA are suggested as the best ways for the characterization of mechanical properties of hydrogel composites, whereas the SAOS rheology is more useful for studying the hydrogel's processing kinetics, as it does not induce volumetric changes even at very high strains. Overall, the results confirmed a beneficial effect of BAG (nano)particles on the elastic modulus of the GG-BAG composite hydrogel. The Young's modulus of 6.6 ± 0.8 kPa for the GG hydrogel increased by two orders of magnitude after the addition of 2 wt.% BAG particles (500-800 kPa).

  4. Effects of geometry and cell-matrix interactions on the mechanics of 3D engineered microtissues

    Science.gov (United States)

    Bose, Prasenjit; Eyckmans, Jeroen; Chen, Christopher; Reich, Daniel

    Approaches to measure and control cell-extracellular matrix (ECM) interactions in a dynamic mechanical environment are important both for studies of mechanobiology and for tissue design for bioengineering applications. We have developed a microtissue-based platform capable of controlling the ECM alignment of 3D engineered microtissues while simultaneously permitting measurement of cellular contractile forces and the tissues' mechanical properties. The tissues self-assemble from cell-laden collagen gels placed in micro-fabricated wells containing sets of flexible elastic pillars. Tissue geometry and ECM alignment are controlled by the pillars' number, shape and location. Optical tracking of the pillars provides readout of the tissues' contractile forces. Magnetic materials bound to selected pillars allow quasi-static or dynamic stretching of the tissue, and together with simultaneous measurements of the tissues' local dynamic strain field, enable characterization of the mechanical properties of the system, including their degree of anisotropy. Results on the effects of symmetry and degree of ECM alignment and organization on the role of cell-ECM interactions in determining tissue mechanical properties will be discussed. This work is supported by NSF CMMI-1463011 and CMMI-1462710.

  5. Mechanical loading regulates human MSC differentiation in a multi-layer hydrogel for osteochondral tissue engineering.

    Science.gov (United States)

    Steinmetz, Neven J; Aisenbrey, Elizabeth A; Westbrook, Kristofer K; Qi, H Jerry; Bryant, Stephanie J

    2015-07-01

    A bioinspired multi-layer hydrogel was developed for the encapsulation of human mesenchymal stem cells (hMSCs) as a platform for osteochondral tissue engineering. The spatial presentation of biochemical cues, via incorporation of extracellular matrix analogs, and mechanical cues, via both hydrogel crosslink density and externally applied mechanical loads, were characterized in each layer. A simple sequential photopolymerization method was employed to form stable poly(ethylene glycol)-based hydrogels with a soft cartilage-like layer of chondroitin sulfate and low RGD concentrations, a stiff bone-like layer with high RGD concentrations, and an intermediate interfacial layer. Under a compressive load, the variation in hydrogel stiffness within each layer produced high strains in the soft cartilage-like layer, low strains in the stiff bone-like layer, and moderate strains in the interfacial layer. When hMSC-laden hydrogels were cultured statically in osteochondral differentiation media, the local biochemical and matrix stiffness cues were not sufficient to spatially guide hMSC differentiation after 21 days. However dynamic mechanical stimulation led to differentially high expression of collagens with collagen II in the cartilage-like layer, collagen X in the interfacial layer and collagen I in the bone-like layer and mineral deposits localized to the bone layer. Overall, these findings point to external mechanical stimulation as a potent regulator of hMSC differentiation toward osteochondral cellular phenotypes. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  6. APPLICATION OF APM WINMACHINE SOFTWARE FOR DESIGN AND CALCULATIONS IN MECHANICAL ENGINEERING

    Directory of Open Access Journals (Sweden)

    L. O. Neduzha

    2016-04-01

    Full Text Available Purpose.To conduct the research at all stages of design, development, operation, residual operation life determination, namely, preliminary study, action principle choice, design of draft and technical projects, their optimization, preparation of design documentation and control information for automated production, comprehensive engineering analysis, it is required to use the latest computer technologies. Their use can not only present data and information in some way, but also gives the opportunity to effectively and directly interact with the information object that is created or demonstrated. Methodology.To perform engineering calculations associated with the analysis of the strength of machines, mechanisms, constructions one uses both analytical and numerical methods in practice.The most common method for analysing the stress-strain state of object models, obtaining their dynamic and stability characteristics at constant and variable modes of external load is the finite element method, which is implemented in many famous and widespread software products, providing strength calculation of models of machines, mechanisms and structures. Findings.The use of modern software for designing machine parts and various types of their joints and for strength analysis of structures is justified. Colour charts for distribution of stresses, displacement, internal efforts, safety factor and others allow accurate and quick identification of the most dangerous places in the structure. The program also provides an opportunity to «look» inside the elements and see the resulting distribution of internal force factors. Originality.The paper considered the aspects, which are unexplored at present, associated with the current state and prospects of development of industrial production, the use of software package for design and calculations in the mechanical industry. The result of the work is the justification of software application for solving problems that

  7. Dynamic Mechanical Compression of Chondrocytes for Tissue Engineering: A Critical Review.

    Science.gov (United States)

    Anderson, Devon E; Johnstone, Brian

    2017-01-01

    species, and complex loading regimes, did not necessarily corroborate prior positive results. These studies report positive results with respect to very specific conditions for cellular responses to dynamic load but fail to consistently achieve significant positive changes in relevant tissue engineering parameters, particularly collagen content and stiffness. There is a need for standardized methods and analyses of dynamic mechanical loading systems to guide the field of tissue engineering toward building cartilaginous implants that meet the goal of regenerating articular cartilage.

  8. Dynamic Mechanical Compression of Chondrocytes for Tissue Engineering: A Critical Review

    Directory of Open Access Journals (Sweden)

    Devon E. Anderson

    2017-12-01

    derived from different species, and complex loading regimes, did not necessarily corroborate prior positive results. These studies report positive results with respect to very specific conditions for cellular responses to dynamic load but fail to consistently achieve significant positive changes in relevant tissue engineering parameters, particularly collagen content and stiffness. There is a need for standardized methods and analyses of dynamic mechanical loading systems to guide the field of tissue engineering toward building cartilaginous implants that meet the goal of regenerating articular cartilage.

  9. Infusion of Emerging Technologies and New Teaching Methods into the Mechanical Engineering Curriculum at the City College of New York

    Science.gov (United States)

    Delale, Feridun; Liaw, Benjamin M.; Jiji, Latif M.; Voiculescu, Ioana; Yu, Honghui

    2011-01-01

    From October 2003 to April 2008 a systemic reform of the Mechanical Engineering program at The City College of New York was undertaken with the goal of incorporating emerging technologies (such as nanotechnology, biotechnology, Micro-Electro-Mechanical Systems (MEMS), intelligent systems) and new teaching methodologies (such as project based…

  10. Example of Good Practice of a Learning Environment with a Classroom Response System in a Mechanical Engineering Bachelor Course

    Science.gov (United States)

    Arteaga, Ines Lopez; Vinken, Esther

    2013-01-01

    Results of a successful pilot study are presented, in which quizzes are introduced in a second year bachelor course for mechanical engineering students. The pilot study course entailed the basic concepts of mechanical vibrations in complex, realistic structures. The quiz is held weekly using a SharePoint application. The purpose of the quizzes is…

  11. Active Bodies, Active Minds: A Case Study on Physical Activity and Academic Success in Lawrence, Massachusetts. Understanding Boston

    Science.gov (United States)

    Sacheck, Jennifer; Wright, Catherine; Chomitz, Virginia; Chui, Kenneth; Economos, Christina; Schultz, Nicole

    2015-01-01

    This case study addresses two major priorities of the Boston Foundation--health and education. Since the 2007 publication of the "Understanding Boston" report "The Boston Paradox: Lots of Health Care, Not Enough Health," the Boston Foundation has worked to draw attention to the epidemic of preventable chronic disease that not…

  12. Replication of engine block cylinder bridge microstructure and mechanical properties with lab scale 319 Al alloy billet castings

    International Nuclear Information System (INIS)

    Lombardi, A.; D'Elia, F.; Ravindran, C.; MacKay, R.

    2014-01-01

    In recent years, aluminum alloy gasoline engine blocks have in large part successfully replaced nodular cast iron engine blocks, resulting in improved vehicle fuel efficiency. However, because of the inadequate wear resistance properties of hypoeutectic Al–Si alloys, gray iron cylinder liners are required. These liners cause the development of large tensile residual stress along the cylinder bores and necessitate the maximization of mechanical properties in this region to prevent premature engine failure. The aim of this study was to replicate the engine cylinder bridge microstructure and mechanical properties following TSR treatment (which removes the sand binder to enable easy casting retrieval) using lab scale billet castings of the same alloy composition with varying cooling rates. Comparisons in microstructure between the engine block and the billet castings were carried out using optical and scanning electron microscopy, while mechanical properties were assessed using tensile testing. The results suggest that the microstructure at the top and middle of the engine block cylinder bridge was successfully replicated by the billet castings. However, the microstructure at the bottom of the cylinder was not completely replicated due to variations in secondary phase morphology and distribution. The successful replication of engine block microstructure will enable the future optimization of heat treatment parameters. - Highlights: • A method to replicate engine block microstructure was developed. • Billet castings will allow cost effective optimization of heat treatment process. • The replication of microstructure in the cylinder region was mostly successful. • Porosity was more clustered in the billet castings compared to the engine block. • Mechanical properties were lower in billet castings due to porosity and inclusions

  13. Replication of engine block cylinder bridge microstructure and mechanical properties with lab scale 319 Al alloy billet castings

    Energy Technology Data Exchange (ETDEWEB)

    Lombardi, A., E-mail: a2lombar@ryerson.ca [Centre for Near-net-shape Processing of Materials, Ryerson University, 101 Gerrard Street East, Toronto, Ontario M5B2K3 (Canada); D' Elia, F.; Ravindran, C. [Centre for Near-net-shape Processing of Materials, Ryerson University, 101 Gerrard Street East, Toronto, Ontario M5B2K3 (Canada); MacKay, R. [Nemak of Canada Corporation, 4600 G.N. Booth Drive, Windsor, Ontario N9C4G8 (Canada)

    2014-01-15

    In recent years, aluminum alloy gasoline engine blocks have in large part successfully replaced nodular cast iron engine blocks, resulting in improved vehicle fuel efficiency. However, because of the inadequate wear resistance properties of hypoeutectic Al–Si alloys, gray iron cylinder liners are required. These liners cause the development of large tensile residual stress along the cylinder bores and necessitate the maximization of mechanical properties in this region to prevent premature engine failure. The aim of this study was to replicate the engine cylinder bridge microstructure and mechanical properties following TSR treatment (which removes the sand binder to enable easy casting retrieval) using lab scale billet castings of the same alloy composition with varying cooling rates. Comparisons in microstructure between the engine block and the billet castings were carried out using optical and scanning electron microscopy, while mechanical properties were assessed using tensile testing. The results suggest that the microstructure at the top and middle of the engine block cylinder bridge was successfully replicated by the billet castings. However, the microstructure at the bottom of the cylinder was not completely replicated due to variations in secondary phase morphology and distribution. The successful replication of engine block microstructure will enable the future optimization of heat treatment parameters. - Highlights: • A method to replicate engine block microstructure was developed. • Billet castings will allow cost effective optimization of heat treatment process. • The replication of microstructure in the cylinder region was mostly successful. • Porosity was more clustered in the billet castings compared to the engine block. • Mechanical properties were lower in billet castings due to porosity and inclusions.

  14. BANGLADESH EPZS AS AN EXAMPLE FOR DEVELOPMENT OF RUSSIAN MECHANIC ENGINEERING

    Directory of Open Access Journals (Sweden)

    P. P. Bogdanenko

    2015-01-01

    Full Text Available The subject of the article is export processing zones of Bangladesh, which may become a sample for development of mechanic engineering in Russia. Export processing zone, as a kind of special economic zones, is a quite useful tool for the country's economy. They allow reaching a number of government objectives: increase employment, attract investment and enhance volume of collected taxes. In addition to the direct eff ect, the emergence of export processing zones has indirect impact on the economy by increasing purchases from suppliers by SEZ residents. Providing tax and customs benefi ts to residents, the state puts companies outside the zones at a disadvantage. However, to counter this, state imposes restrictions on admission of products of resident companies on domestic market. These restrictions may relate to establishment either of a certain percentage of products that can be delivered freely on the internal market or share that can be delivered after payment of customs duties and taxes. The purpose of this work is to show the results of Bangladesh EPZs and to present basic directions of development for such zone specialized in mechanic engineering in Russia. The methodological base of the research is comparative analysis, cause-eff ect relationships, as well as historical method. In this article the author analyzes the experience of creation of export processing zones in Bangladesh, where they are suffi ciently proven: new jobs and enterprises have been created - investments to these zones account for a signifi cant share of total investments to the country. Moreover export of Bangladesh has increased signifi cantly. At the same time the goal for diversifying the country industry has not been met: textile is the main branch is in these zones. At the article the author points to the possibility of using this experience in Russia in terms of mechanic engineering. Availability of qualifi ed personnel, training base, transfer of

  15. Hybrid printing of mechanically and biologically improved constructs for cartilage tissue engineering applications

    International Nuclear Information System (INIS)

    Xu Tao; Binder, Kyle W; Albanna, Mohammad Z; Dice, Dennis; Zhao Weixin; Yoo, James J; Atala, Anthony

    2013-01-01

    Bioprinting is an emerging technique used to fabricate viable, 3D tissue constructs through the precise deposition of cells and hydrogels in a layer-by-layer fashion. Despite the ability to mimic the native properties of tissue, printed 3D constructs that are composed of naturally-derived biomaterials still lack structural integrity and adequate mechanical properties for use in vivo, thus limiting their development for use in load-bearing tissue engineering applications, such as cartilage. Fabrication of viable constructs using a novel multi-head deposition system provides the ability to combine synthetic polymers, which have higher mechanical strength than natural materials, with the favorable environment for cell growth provided by traditional naturally-derived hydrogels. However, the complexity and high cost associated with constructing the required robotic system hamper the widespread application of this approach. Moreover, the scaffolds fabricated by these robotic systems often lack flexibility, which further restrict their applications. To address these limitations, advanced fabrication techniques are necessary to generate complex constructs with controlled architectures and adequate mechanical properties. In this study, we describe the construction of a hybrid inkjet printing/electrospinning system that can be used to fabricate viable tissues for cartilage tissue engineering applications. Electrospinning of polycaprolactone fibers was alternated with inkjet printing of rabbit elastic chondrocytes suspended in a fibrin–collagen hydrogel in order to fabricate a five-layer tissue construct of 1 mm thickness. The chondrocytes survived within the printed hybrid construct with more than 80% viability one week after printing. In addition, the cells proliferated and maintained their basic biological properties within the printed layered constructs. Furthermore, the fabricated constructs formed cartilage-like tissues both in vitro and in vivo as evidenced by the

  16. Future Nuisance Flooding at Boston Caused by Astronomical Tides Alone

    Science.gov (United States)

    Ray, Richard D.; Foster, Grant

    2016-01-01

    Sea level rise necessarily triggers more occurrences of minor, or nuisance, flooding events along coastlines, a fact well documented in recent studies. At some locations nuisance flooding can be brought about merely by high spring tides, independent of storms, winds, or other atmospheric conditions. Analysis of observed water levels at Boston indicates that tidal flooding began to occur there in 2011 and will become more frequent in subsequent years. A compilation of all predicted nuisance-flooding events, induced by astronomical tides alone, is presented through year 2050. The accuracy of the tide prediction is improved when several unusual properties of Gulf of Maine tides, including secular changes, are properly accounted for. Future mean sea-level rise at Boston cannot be predicted with comparable confidence, so two very different climate scenarios are adopted; both predict a large increase in the frequency and the magnitude of tidal flooding events.

  17. Mechanically activated fly ash as a high performance binder for civil engineering

    International Nuclear Information System (INIS)

    Rieger, D; Kullová, L; Čekalová, M; Novotný, P; Pola, M

    2017-01-01

    This study is aimed for investigation of fly ash binder with suitable properties for civil engineering needs. The fly ash from Czech brown coal power plant Prunerov II was used and mechanically activated to achieve suitable particle size for alkaline activation of hardening process. This process is driven by dissolution of aluminosilicate content of fly ash and by subsequent development of inorganic polymeric network called geopolymer. Hardening kinetics at 25 and 30 °C were measured by strain controlled small amplitude oscillatory rheometry with strain of 0.01 % and microstructure of hardened binder was evaluated by scanning electron microscopy. Strength development of hardened binder was investigated according to compressional and flexural strength for a period of 180 days. Our investigation finds out, that mechanically activated fly ash can be comparable to metakaolin geopolymers, according to setting time and mechanical parameters even at room temperature curing. Moreover, on the bases of long time strength development, achieved compressional strength of 134.5 after 180 days is comparable to performance of high grade Portland cement concretes. (paper)

  18. Cyanobacterial defense mechanisms against foreign DNA transfer and their impact on genetic engineering

    Directory of Open Access Journals (Sweden)

    Karina Stucken

    2013-01-01

    Full Text Available Cyanobacteria display a large diversity of cellular forms ranging from unicellular to complex multicellular filaments or aggregates. Species in the group present a wide range of metabolic characteristics including the fixation of atmospheric nitrogen, resistance to extreme environments, production of hydrogen, secondary metabolites and exopolysaccharides. These characteristics led to the growing interest in cyanobacteria across the fields of ecology, evolution, cell biology and biotechnology. The number of available cyanobacterial genome sequences has increased considerably in recent years, with more than 140 fully sequenced genomes to date. Genetic engineering of cyanobacteria is widely applied to the model unicellular strains Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942. However the establishment of transformation protocols in many other cyanobacterial strains is challenging. One obstacle to the development of these novel model organisms is that many species have doubling times of 48 h or more, much longer than the bacterial models E. coli or B. subtilis. Furthermore, cyanobacterial defense mechanisms against foreign DNA pose a physical and biochemical barrier to DNA insertion in most strains. Here we review the various barriers to DNA uptake in the context of lateral gene transfer among microbes and the various mechanisms for DNA acquisition within the prokaryotic domain. Understanding the cyanobacterial defense mechanisms is expected to assist in the development and establishment of novel transformation protocols that are specifically suitable for this group.

  19. Additively Manufactured Scaffolds for Bone Tissue Engineering and the Prediction of their Mechanical Behavior: A Review.

    Science.gov (United States)

    Zhang, Xiang-Yu; Fang, Gang; Zhou, Jie

    2017-01-10

    Additive manufacturing (AM), nowadays commonly known as 3D printing, is a revolutionary materials processing technology, particularly suitable for the production of low-volume parts with high shape complexities and often with multiple functions. As such, it holds great promise for the fabrication of patient-specific implants. In recent years, remarkable progress has been made in implementing AM in the bio-fabrication field. This paper presents an overview on the state-of-the-art AM technology for bone tissue engineering (BTE) scaffolds, with a particular focus on the AM scaffolds made of metallic biomaterials. It starts with a brief description of architecture design strategies to meet the biological and mechanical property requirements of scaffolds. Then, it summarizes the working principles, advantages and limitations of each of AM methods suitable for creating porous structures and manufacturing scaffolds from powdered materials. It elaborates on the finite-element (FE) analysis applied to predict the mechanical behavior of AM scaffolds, as well as the effect of the architectural design of porous structure on its mechanical properties. The review ends up with the authors' view on the current challenges and further research directions.

  20. Mechanisms relevant to the enhanced virulence of a dihydroxynaphthalene-melanin metabolically engineered entomopathogen.

    Directory of Open Access Journals (Sweden)

    Min-Nan Tseng

    Full Text Available The entomopathogenic fungus Metarhizium anisopliae MA05-169 is a transformant strain that has been metabolically engineered to express dihydroxynaphthalene-melanin biosynthesis genes. In contrast to the wild type strain, the transformant displays a greater resistance to environmental stress and a higher virulence toward target insect host. However, the underlying mechanisms for these characteristics remain unclear; hence experiments were initiated to explore the possible mechanism(s through physiological and molecular approaches. Although both transformant and wild type strains could infect and share the same insect host range, the former germinated faster and produced more appressoria than the latter, both in vivo and in vitro. The transformant showed a significantly shorter median lethal time (LT50 when infecting the diamondback moth (Plutella xylostella and the striped flea beetle (Phyllotreta striolata, than the wild type. Additionally, the transformant was more tolerant to reactive oxygen species (ROS, produced 40-fold more orthosporin and notably overexpressed the transcripts of the pathogenicity-relevant hydrolytic enzymes (chitinase, protease, and phospholipase genes in vivo. In contrast, appressorium turgor pressure and destruxin A content were slightly decreased compared to the wild type. The transformant's high anti-stress tolerance, its high virulence against five important insect pests (cowpea aphid Aphis craccivora, diamondback moth Pl. xylostella, striped flea beetle Ph. striolata, and silverleaf whitefly Bemisia argentifolii and its capacity to colonize the root system are key properties for its potential bio-control field application.

  1. Enhanced mechanical properties of thermosensitive chitosan hydrogel by silk fibers for cartilage tissue engineering.

    Science.gov (United States)

    Mirahmadi, Fereshteh; Tafazzoli-Shadpour, Mohammad; Shokrgozar, Mohammad Ali; Bonakdar, Shahin

    2013-12-01

    Articular cartilage has limited repair capability following traumatic injuries and current methods of treatment remain inefficient. Reconstructing cartilage provides a new way for cartilage repair and natural polymers are often used as scaffold because of their biocompatibility and biofunctionality. In this study, we added degummed chopped silk fibers and electrospun silk fibers to the thermosensitive chitosan/glycerophosphate hydrogels to reinforce two hydrogel constructs which were used as scaffold for hyaline cartilage regeneration. The gelation temperature and gelation time of hydrogel were analyzed by the rheometer and vial tilting method. Mechanical characterization was measured by uniaxial compression, indentation and dynamic mechanical analysis assay. Chondrocytes were then harvested from the knee joint of the New Zealand white rabbits and cultured in constructs. The cell proliferation, viability, production of glycosaminoglycans and collagen type II were assessed. The results showed that mechanical properties of the hydrogel were significantly enhanced when a hybrid with two layers of electrospun silk fibers was made. The results of GAG and collagen type II in cell-seeded scaffolds indicate support of the chondrogenic phenotype for chondrocytes with a significant increase in degummed silk fiber-hydrogel composite for GAG content and in two-layer electrospun fiber-hydrogel composite for Col II. It was concluded that these two modified scaffolds could be employed for cartilage tissue engineering. © 2013.

  2. Development of the mechanical properties of engineered skin substitutes after grafting to full-thickness wounds.

    Science.gov (United States)

    Sander, Edward A; Lynch, Kaari A; Boyce, Steven T

    2014-05-01

    Engineered skin substitutes (ESSs) have been reported to close full-thickness burn wounds but are subject to loss from mechanical shear due to their deficiencies in tensile strength and elasticity. Hypothetically, if the mechanical properties of ESS matched those of native skin, losses due to shear or fracture could be reduced. To consider modifications of the composition of ESS to improve homology with native skin, biomechanical analyses of the current composition of ESS were performed. ESSs consist of a degradable biopolymer scaffold of type I collagen and chondroitin-sulfate (CGS) that is populated sequentially with cultured human dermal fibroblasts (hF) and epidermal keratinocytes (hK). In the current study, the hydrated biopolymer scaffold (CGS), the scaffold populated with hF dermal skin substitute (DSS), or the complete ESS were evaluated mechanically for linear stiffness (N/mm), ultimate tensile load at failure (N), maximum extension at failure (mm), and energy absorbed up to the point of failure (N-mm). These biomechanical end points were also used to evaluate ESS at six weeks after grafting to full-thickness skin wounds in athymic mice and compared to murine autograft or excised murine skin. The data showed statistically significant differences (p clinical morbidity from graft loss.

  3. Prehistory effects on the VHCF behaviour of engineering metallic materials with different strengthening mechanisms

    International Nuclear Information System (INIS)

    Zimmermann, M; Stoecker, C; Mueller-Bollenhagen, C; Christ, H-J

    2010-01-01

    Engineering materials often undergo a plastic deformation during manufacturing, hence the effect of a predeformation on the subsequent fatigue behaviour has to be considered. The effect of a prestrain on the microstructure is strongly influenced by the strengthening mechanism. Different mechanisms are relevant in the materials applied in this study: a solid-solution hardened and a precipitation-hardened nickel-base alloy and a martensite-forming metastable austenitic steel. Prehistory effects become very important, when fatigue failure at very high number of cycles (N > 10 7 ) is considered, since damage mechanisms occur different to those observed in the range of conventional fatigue limit. With the global strain amplitude being well below the static elastic limit, only inhomogeneously distributed local plastic deformation takes place in the very high cycle fatigue (VHCF) region. The dislocation motion during cyclic loading thus depends on the effective flow stress, which is defined by the global cyclic stress-strain relation and the local stress distribution as a consequence of the interaction between dislocations and precipitates, grain boundaries, martensite phases and micro-notches. As a consequence, no significant prehistory effect was observed for the VHCF behaviour of the solid-solution hardening alloy, while the precipitation-hardening alloy shows a perceptible prehistory dependence. In the case of the austenitic steel, strain-hardening and the volume fraction of the deformation-induced martensite dominate the fatigue behaviour.

  4. 78 FR 9730 - Boston Harbor Islands Advisory Council Meeting

    Science.gov (United States)

    2013-02-11

    .... The agenda includes a presentation by Sally Snowman, 70th keeper of Boston Light, the election of officers, and a park update. Date/Time: March 6, 2013, 6:00 p.m. to 8:00 p.m. (Eastern). Location: Wilmer... information--may be made publicly available at any time. While you can ask us in your comment to withhold your...

  5. Mapping urban pipeline leaks: Methane leaks across Boston

    International Nuclear Information System (INIS)

    Phillips, Nathan G.; Ackley, Robert; Crosson, Eric R.; Down, Adrian; Hutyra, Lucy R.; Brondfield, Max; Karr, Jonathan D.; Zhao Kaiguang; Jackson, Robert B.

    2013-01-01

    Natural gas is the largest source of anthropogenic emissions of methane (CH 4 ) in the United States. To assess pipeline emissions across a major city, we mapped CH 4 leaks across all 785 road miles in the city of Boston using a cavity-ring-down mobile CH 4 analyzer. We identified 3356 CH 4 leaks with concentrations exceeding up to 15 times the global background level. Separately, we measured δ 13 CH 4 isotopic signatures from a subset of these leaks. The δ 13 CH 4 signatures (mean = −42.8‰ ± 1.3‰ s.e.; n = 32) strongly indicate a fossil fuel source rather than a biogenic source for most of the leaks; natural gas sampled across the city had average δ 13 CH 4 values of −36.8‰ (±0.7‰ s.e., n = 10), whereas CH 4 collected from landfill sites, wetlands, and sewer systems had δ 13 CH 4 signatures ∼20‰ lighter (μ = −57.8‰, ±1.6‰ s.e., n = 8). Repairing leaky natural gas distribution systems will reduce greenhouse gas emissions, increase consumer health and safety, and save money. Highlights: ► We mapped 3356 methane leaks in Boston. ► Methane leaks in Boston carry an isotopic signature of pipeline natural gas. ► Replacing failing gas pipelines will provide safety, environmental, and economic benefits. - We identified 3356 methane leaks in Boston, with isotopic characteristics consistent with pipeline natural gas.

  6. Personal Hygiene Practices among Urban Homeless Persons in Boston, MA

    OpenAIRE

    Leibler, Jessica H.; Nguyen, Daniel D.; Le?n, Casey; Gaeta, Jessie M.; Perez, Debora

    2017-01-01

    Persons experiencing homelessness in the United States experience significant barriers to self-care and personal hygiene, including limited access to clean showers, laundry and hand washing facilities. While the obstacles to personal hygiene associated with homelessness may increase risk of infectious disease, hygiene-related behaviors among people experiencing homelessness has received limited attention. We conducted a cross-sectional study of individuals experiencing homelessness in Boston,...

  7. Do foreclosures affect Boston public school student academic performance?

    OpenAIRE

    Bradbury, Katharine L.; Burke, Mary A.; Triest, Robert K.

    2013-01-01

    Foreclosures have well-documented adverse consequences for families living in or owning properties undergoing foreclosure and on surrounding neighborhoods, but they may also have other costs. This policy brief summarizes our research on the impact of mortgage foreclosures on academic performance among Boston public school students. The data show that students who live at an address that experiences a foreclosure tend to score substantially lower on standardized tests (math and English) and al...

  8. From Boston to the Balkans: Olmsted’s Emerald Legacy

    Directory of Open Access Journals (Sweden)

    Christina Luke

    2013-01-01

    Full Text Available This article explores the legacy of landscape architect Fredrick Law Olmsted on modern cultural tourism policies. The author explains the involvement of Olmsted in the founding of Yosemite National Park, and describes the influence of this experience on his later work on the Emerald Necklace parks project in Boston. This became a model for natural and cultural corridors worldwide, including those in the Balkans and Turkey.

  9. Engineering mechanical gradients in next generation biomaterials - Lessons learned from medical textile design.

    Science.gov (United States)

    Ng, Joanna L; Collins, Ciara E; Knothe Tate, Melissa L

    2017-07-01

    facilitate transport of molecules and cells during tissue genesis within tissue defects (surgical membranes). External and internal biomaterial membranes prescribe boundary conditions for treatment of medical disorders, from oedema to tissue defects. Studies are needed to guide the design of next generation biomaterials and devices that incorporate gradient engineering approaches, which offer great potential to enhance function in a dynamic and physiological context. Mechanical gradients intrinsic to currently implemented biomaterials such as medical textiles and surgical interface membranes are poorly understood. Here we characterise quantitatively the mechanics of textile and nonwoven biomaterial membranes for external and internal use. The lack of seamless gradients in compression medical textiles contrasts with the graded mechanical effects achieved by elastomeric exercise bands, which are designed to deliver controlled, incremental increases in loading to facilitate healing as injured tissues return to normal structure and function. Engineering textiles with a prescient choice of fibre composition/size, type of knit/weave and inlay fibres, and weave density/anisotropy will enable creation of fabrics that can deliver spatially and temporally controlled mechanical gradients to maintain force balances at tissue boundaries, e.g. to treat oedema or tissue defects. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  10. The critical chemical and mechanical regulation of folic acid on neural engineering.

    Science.gov (United States)

    Kim, Gloria B; Chen, Yongjie; Kang, Weibo; Guo, Jinshan; Payne, Russell; Li, Hui; Wei, Qiong; Baker, Julianne; Dong, Cheng; Zhang, Sulin; Wong, Pak Kin; Rizk, Elias B; Yan, Jiazhi; Yang, Jian

    2018-04-03

    The mandate of folic acid supplementation in grained products has reduced the occurrence of neural tube defects by one third in the U.S since its introduction by the Food and Drug Administration in 1998. However, the advantages and possible mechanisms of action of using folic acid for peripheral nerve engineering and neurological diseases still remain largely elusive. Herein, folic acid is described as an inexpensive and multifunctional niche component that modulates behaviors in different cells in the nervous system. The multiple benefits of modulation include: 1) generating chemotactic responses on glial cells, 2) inducing neurotrophin release, and 3) stimulating neuronal differentiation of a PC-12 cell system. For the first time, folic acid is also shown to enhance cellular force generation and global methylation in the PC-12 cells, thereby enabling both biomechanical and biochemical pathways to regulate neuron differentiation. These findings are evaluated in vivo for clinical translation. Our results suggest that folic acid-nerve guidance conduits may offer significant benefits as a low-cost, off-the-shelf product for reaching the functional recovery seen with autografts in large sciatic nerve defects. Consequently, folic acid holds great potential as a critical and convenient therapeutic intervention for neural engineering, regenerative medicine, medical prosthetics, and drug delivery. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Progress and challenges of engineering a biophysical CO2-concentrating mechanism into higher plants.

    Science.gov (United States)

    Rae, Benjamin D; Long, Benedict M; Förster, Britta; Nguyen, Nghiem D; Velanis, Christos N; Atkinson, Nicky; Hee, Wei Yih; Mukherjee, Bratati; Price, G Dean; McCormick, Alistair J

    2017-06-01

    Growth and productivity in important crop plants is limited by the inefficiencies of the C3 photosynthetic pathway. Introducing CO2-concentrating mechanisms (CCMs) into C3 plants could overcome these limitations and lead to increased yields. Many unicellular microautotrophs, such as cyanobacteria and green algae, possess highly efficient biophysical CCMs that increase CO2 concentrations around the primary carboxylase enzyme, Rubisco, to enhance CO2 assimilation rates. Algal and cyanobacterial CCMs utilize distinct molecular components, but share several functional commonalities. Here we outline the recent progress and current challenges of engineering biophysical CCMs into C3 plants. We review the predicted requirements for a functional biophysical CCM based on current knowledge of cyanobacterial and algal CCMs, the molecular engineering tools and research pipelines required to translate our theoretical knowledge into practice, and the current challenges to achieving these goals. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  12. Teaching-Learning-Based Optimization with Learning Enthusiasm Mechanism and Its Application in Chemical Engineering

    Directory of Open Access Journals (Sweden)

    Xu Chen

    2018-01-01

    Full Text Available Teaching-learning-based optimization (TLBO is a population-based metaheuristic search algorithm inspired by the teaching and learning process in a classroom. It has been successfully applied to many scientific and engineering applications in the past few years. In the basic TLBO and most of its variants, all the learners have the same probability of getting knowledge from others. However, in the real world, learners are different, and each learner’s learning enthusiasm is not the same, resulting in different probabilities of acquiring knowledge. Motivated by this phenomenon, this study introduces a learning enthusiasm mechanism into the basic TLBO and proposes a learning enthusiasm based TLBO (LebTLBO. In the LebTLBO, learners with good grades have high learning enthusiasm, and they have large probabilities of acquiring knowledge from others; by contrast, learners with bad grades have low learning enthusiasm, and they have relative small probabilities of acquiring knowledge from others. In addition, a poor student tutoring phase is introduced to improve the quality of the poor learners. The proposed method is evaluated on the CEC2014 benchmark functions, and the computational results demonstrate that it offers promising results compared with other efficient TLBO and non-TLBO algorithms. Finally, LebTLBO is applied to solve three optimal control problems in chemical engineering, and the competitive results show its potential for real-world problems.

  13. Inconceivable events in handling material in a heavy mechanical engineering industry

    International Nuclear Information System (INIS)

    Oestberg, G.; Hoffstedt, H.; Holm, G.; Klingenstierna, B.; Rydnert, B.; Samsonowitz, V.; Sjoeberg, L.

    1977-05-01

    This report accounts for an exploratory project concerning so-called inconceivable events in a manufacturing process. The study was performed at a medium-sized mechanical engineering company manufacturing heavy welded constructions with high demands on reliability and safety. On the basis of experience gained in the present study the main study shall deal with inconceivable events during the manufacture of welded nuclear pressure vessels. First, a description is given of the background and conditions of the project. On this follows a technical description of the studied process, and an account is given of observations and results of interviews at the company as well. In the light of this, an attempt to find a pattern of inconceivable events was done, and a model for analysis of rare events was developed. By means of this model and earlier described events, causes of unpredicted or unexpected events are discussed. Finally the methodology applied in the study is accounted for and discussed

  14. The use of mechanically activated micronized coal in thermal power engineering

    Directory of Open Access Journals (Sweden)

    Burdukov Anatoliy P.

    2016-01-01

    Full Text Available Coal is one of the main energy resources and development of new promising technologies on its basis is certainly topical. This article discusses the use of new technology of gas and fuel oil replacement by mechanically activated micronized coal in power engineering: ignition and stabilization of pulverized coal flame combustion, as well as gasification of micronized coal in the flow. The new technology coal combustion with two stages of grinding is suggested. Optimization of the scheme of two-stage combustion is calculated. The first experimental data on the combustion process are obtained. The first demonstration tests on gas and heavy oil replacement by micronized coal during boiler ignition were carried out in the real power boiler with the capacity of 320 tons of steam per hour.

  15. Electro-Mechanical Response and Engineering Properties of Piezocomposite with Imperfect Interface

    Directory of Open Access Journals (Sweden)

    Tippayaphalapholgul Rattanan

    2016-01-01

    Full Text Available Composites of piezoelectric materials are widely use in practical applications such as nondestructive testing devices, smart adaptive structures and medical devices. A thorough understanding of coupled electro-elastic response and properties of piezocomposite are crucial for the development and design of piezoelectric composite materials used in advanced applications. The micromechanics analysis is employed in this paper to determine the response and engineering properties of the piezocomposite. A mechanical imperfect interface bonding between piezoelectric inclusion and polymer matrix is taken into consideration in the analysis. The micromechanics analysis is based on the Boundary Element Method (BEM together with the periodic micro-field micromechanics theory. A selected set of numerical results is presented to investigate the influence of volume ratio and interface bonding condition on effective piezocomposite material coefficients and portray basic features of coupled electroelastic response within the domain of piezocomposite unit cell.

  16. Distortions and gender-related differences in the perception of mechanical engineering in high school students.

    Science.gov (United States)

    Ferrando Piera, Pere Joan; Gutiérrez-Colón Plana, Mar; Paleo Cageao, Paloma; de la Flor López, Silvia; Ferrando Piera, Francesc

    2013-01-01

    The reason for this study was the low interest that high school students, particularly females, show for the subject of mechanical engineering (ME). We assumed that this problem was partly due to: (a) lack of understanding of the tasks involved in ME, and (b) a distorted and negative perception of the professional environment and working conditions. To assess these two assumptions, two measurement instruments (tasks and perceptions) were developed and administered in a sample of 496 high school students. A multiple-group design was used and data was analyzed by using an extended item response theory model. In general terms, the results agreed with our expectations. However, no significant gender differences were found. The implications of the results for future improvements are discussed.

  17. The Evaluation of Industry Practical of Mechanical Engineering in Vocational Education: A CIPP Model Approach

    Science.gov (United States)

    Kamaludin, M.; Munawar, W.; Mahdan, D.; Simanjuntak, M. V.; Wendi, H. F.

    2018-02-01

    The learning system is not only studied on campus but also practicing in the world of work. Industry Practical aims to enable students to develop their skills in accordance with the real world of work. To know the success of the implementation of industry practical program then held evaluation. The evaluation of the program in this study used the CIPP evaluation approach (Context, Input, Process, Product). The purpose of this research is to know the extent of achievement and success of industry practical program at vocational school in Bandung with descriptive research method using mix method approach. The sample in this research is students majoring in mechanical engineering in the city of Bandung who have done industry practical.

  18. Mechanical and fracture properties at impact loading of selected steels for nuclear power engineering

    International Nuclear Information System (INIS)

    Buchar, J.; Bilek, Z.

    1988-01-01

    The possibilities are briefly characterized of experimental research of mechanical and fracture properties of steels used in nuclear power engineering. Attention is paid to plastic deformation and the assessment of fracture formation during impact loading. The results are reported for steels 15Kh2MFA and 10GN2MFA. For steel 15Kh2MFA the effect was also studied of neutron radiation at different temperatures. From the theory developed for non-irradiated material 10GN2MFA, a prediction is made within the original model of the fracture stress value for steel 15Kh2MFA in both non-irradiated and irradiated states. The conclusion is arrived at that the existing methods of assessing steel properties at impact load allow obtaining knowledge of all significant effects during actual stress, this using only small specimens of the materials. (Z.M.). 4 figs., 8 refs

  19. Outsourcing neural active control to passive composite mechanics: a tissue engineered cyborg ray

    Science.gov (United States)

    Gazzola, Mattia; Park, Sung Jin; Park, Kyung Soo; Park, Shirley; di Santo, Valentina; Deisseroth, Karl; Lauder, George V.; Mahadevan, L.; Parker, Kevin Kit

    2016-11-01

    Translating the blueprint that stingrays and skates provide, we create a cyborg swimming ray capable of orchestrating adaptive maneuvering and phototactic navigation. The impossibility of replicating the neural system of batoids fish is bypassed by outsourcing algorithmic functionalities to the body composite mechanics, hence casting the active control problem into a design, passive one. We present a first step in engineering multilevel "brain-body-flow" systems that couple sensory information to motor coordination and movement, leading to behavior. This work paves the way for the development of autonomous and adaptive artificial creatures able to process multiple sensory inputs and produce complex behaviors in distributed systems and may represent a path toward soft-robotic "embodied cognition".

  20. Understanding dental CAD/CAM for restorations--the digital workflow from a mechanical engineering viewpoint.

    Science.gov (United States)

    Tapie, L; Lebon, N; Mawussi, B; Fron Chabouis, H; Duret, F; Attal, J-P

    2015-01-01

    As digital technology infiltrates every area of daily life, including the field of medicine, so it is increasingly being introduced into dental practice. Apart from chairside practice, computer-aided design/computer-aided manufacturing (CAD/CAM) solutions are available for creating inlays, crowns, fixed partial dentures (FPDs), implant abutments, and other dental prostheses. CAD/CAM dental solutions can be considered a chain of digital devices and software for the almost automatic design and creation of dental restorations. However, dentists who want to use the technology often do not have the time or knowledge to understand it. A basic knowledge of the CAD/CAM digital workflow for dental restorations can help dentists to grasp the technology and purchase a CAM/CAM system that meets the needs of their office. This article provides a computer-science and mechanical-engineering approach to the CAD/CAM digital workflow to help dentists understand the technology.

  1. Tensor algebra and tensor analysis for engineers with applications to continuum mechanics

    CERN Document Server

    Itskov, Mikhail

    2015-01-01

    This is the fourth and revised edition of a well-received book that aims at bridging the gap between the engineering course of tensor algebra on the one side and the mathematical course of classical linear algebra on the other side. In accordance with the contemporary way of scientific publications, a modern absolute tensor notation is preferred throughout. The book provides a comprehensible exposition of the fundamental mathematical concepts of tensor calculus and enriches the presented material with many illustrative examples. In addition, the book also includes advanced chapters dealing with recent developments in the theory of isotropic and anisotropic tensor functions and their applications to continuum mechanics. Hence, this monograph addresses graduate students as well as scientists working in this field. In each chapter numerous exercises are included, allowing for self-study and intense practice. Solutions to the exercises are also provided.

  2. Boston's balloon dilatation for treatment of cardiac achalasia

    International Nuclear Information System (INIS)

    Yin Jianguo; Song Jinwen; Yang Yan; Liu Xiaohong; Fu Zhiming; Zhang Yaqin

    2001-01-01

    Objective: To review and summarize effectiveness and method of the Boston's balloon dilation in cardiac achalasia. Methods: The intensified guide wire was inserted into stomach through mouth cavity under TV control. The Boston's balloon was inserted to the cardiac stricture through the guide wire and dilatated with 15% contrast medium with to a maximum diameter for five minutes and then the balloon was dilatated again for 3-5 minutes, all together for 3-4 times. The severe stricture must be pre-dilatated with 20-25 mm diameter balloon. Results: The balloon insertion was technically successful in all 26 patients. The once success of balloon dilation was achieved in 24 patients and twice in other 2. Follow-up time was from 2 weeks to 31 months (mean 10.6 months). Recurrent stenosis had not occurred in all patients. Remission rate of dysphagia was 100%. Esophageal reflux occurred in 3 patients. Conclusions: The Boston's balloon dilatation is simple and effective for treatment of cardiac achalasia. The method sometimes may replace surgical procedure

  3. Effect of Kettlebell Lifting on Physical Condition of Future Mechanical Engineers

    Directory of Open Access Journals (Sweden)

    А. П. Конох

    2016-08-01

    Full Text Available The objective of the paper is to study the effect of exercises with kettlebell lifting elements on the physical condition of future mechanical engineers. Materials and methods. To address the tasks set, the study used the following research methods: theoretical analysis and collation of literary sources; implementation of a pilot program of physical education through kettlebell lifting in higher agricultural educational institutions; methods of mathematical statistics. Research results. The paper focuses on the relevant issue of theoretical and methodological support of the process of improving students' physical condition. The study has determined the effect of kettlebell lifting on the physical condition of the future mechanical engineers involved in maintenance and repair of agricultural equipment and machinery. Kettlebell lifting proves to provide good physical training, has a positive effect on the human body, and strengthens health in general. The research conducted gave grounds to determine that the level of the physical condition of the test group students is satisfactory on all indicators. This meets the requirements set before the future specialists. Conclusions. The study of the effectiveness of kettlebell lifting influence on the physical condition of the test group students yielded positive results. As a result, the training improves the performance of the students’ respiratory and cardiovascular systems, decreases their heart rate and blood pressure, enhances economization of the body systems performance at rest and at load, boosts the reserve capacity of these systems, reduces the recovery period after load, and improves the metabolic processes, which contributes to enhancing the organism tolerance to the unfavorable factors of the profession-related activity.

  4. Public-private partnership from theory to practice: Walgreens and the Boston Public Health Commission supporting each other before and after the Boston bombings.

    Science.gov (United States)

    Martin, Atyia; Williams, Jim

    2014-01-01

    This paper presents an overview of the public health and medical services continuity of operations, response and recovery efforts in the aftermath of the Boston bombings. Countless public and private organisations and agencies came together to support the community and the survivors. The efforts of these organisations define what it means to be Boston Strong.

  5. A structural model for the flexural mechanics of nonwoven tissue engineering scaffolds.

    Science.gov (United States)

    Engelmayr, George C; Sacks, Michael S

    2006-08-01

    The development of methods to predict the strength and stiffness of biomaterials used in tissue engineering is critical for load-bearing applications in which the essential functional requirements are primarily mechanical. We previously quantified changes in the effective stiffness (E) of needled nonwoven polyglycolic acid (PGA) and poly-L-lactic acid (PLLA) scaffolds due to tissue formation and scaffold degradation under three-point bending. Toward predicting these changes, we present a structural model for E of a needled nonwoven scaffold in flexure. The model accounted for the number and orientation of fibers within a representative volume element of the scaffold demarcated by the needling process. The spring-like effective stiffness of the curved fibers was calculated using the sinusoidal fiber shapes. Structural and mechanical properties of PGA and PLLA fibers and PGA, PLLA, and 50:50 PGA/PLLA scaffolds were measured and compared with model predictions. To verify the general predictive capability, the predicted dependence of E on fiber diameter was compared with experimental measurements. Needled nonwoven scaffolds were found to exhibit distinct preferred (PD) and cross-preferred (XD) fiber directions, with an E ratio (PD/XD) of approximately 3:1. The good agreement between the predicted and experimental dependence of E on fiber diameter (R2 = 0.987) suggests that the structural model can be used to design scaffolds with E values more similar to native soft tissues. A comparison with previous results for cell-seeded scaffolds (Engelmayr, G. C., Jr., et al., 2005, Biomaterials, 26(2), pp. 175-187) suggests, for the first time, that the primary mechanical effect of collagen deposition is an increase in the number of fiber-fiber bond points yielding effectively stiffer scaffold fibers. This finding indicated that the effects of tissue deposition on needled nonwoven scaffold mechanics do not follow a rule-of-mixtures behavior. These important results underscore

  6. Methodology for developing teaching activities and materials for use in fluid mechanics courses in undergraduate engineering programs

    Directory of Open Access Journals (Sweden)

    Pedro Javier Gamez-Montero

    2015-03-01

    Full Text Available “Mechanics” and “Fluids” are familiar concepts for any newly-registered engineering student. However, when combined into the term “Fluid Mechanics”, students are thrust into the great unknown. The present article demonstrates the process of adaptation employed by the Fluid Mechanics course in the undergraduate engineering program, along with the teaching methodology, teaching materials and results obtained, evaluating the final objective in terms of student satsfaction and level of learning.

  7. The use of physical and virtual manipulatives in an undergraduate mechanical engineering (Dynamics) course

    Science.gov (United States)

    Pan, Edward A.

    Science, technology, engineering, and mathematics (STEM) education is a national focus. Engineering education, as part of STEM education, needs to adapt to meet the needs of the nation in a rapidly changing world. Using computer-based visualization tools and corresponding 3D printed physical objects may help nontraditional students succeed in engineering classes. This dissertation investigated how adding physical or virtual learning objects (called manipulatives) to courses that require mental visualization of mechanical systems can aid student performance. Dynamics is one such course, and tends to be taught using lecture and textbooks with static diagrams of moving systems. Students often fail to solve the problems correctly and an inability to mentally visualize the system can contribute to student difficulties. This study found no differences between treatment groups on quantitative measures of spatial ability and conceptual knowledge. There were differences between treatments on measures of mechanical reasoning ability, in favor of the use of physical and virtual manipulatives over static diagrams alone. There were no major differences in student performance between the use of physical and virtual manipulatives. Students used the physical and virtual manipulatives to test their theories about how the machines worked, however their actual time handling the manipulatives was extremely limited relative to the amount of time they spent working on the problems. Students used the physical and virtual manipulatives as visual aids when communicating about the problem with their partners, and this behavior was also seen with Traditional group students who had to use the static diagrams and gesture instead. The explanations students gave for how the machines worked provided evidence of mental simulation; however, their causal chain analyses were often flawed, probably due to attempts to decrease cognitive load. Student opinions about the static diagrams and dynamic

  8. Enhanced mechanical properties of thermosensitive chitosan hydrogel by silk fibers for cartilage tissue engineering

    International Nuclear Information System (INIS)

    Mirahmadi, Fereshteh; Tafazzoli-Shadpour, Mohammad; Shokrgozar, Mohammad Ali; Bonakdar, Shahin

    2013-01-01

    Articular cartilage has limited repair capability following traumatic injuries and current methods of treatment remain inefficient. Reconstructing cartilage provides a new way for cartilage repair and natural polymers are often used as scaffold because of their biocompatibility and biofunctionality. In this study, we added degummed chopped silk fibers and electrospun silk fibers to the thermosensitive chitosan/glycerophosphate hydrogels to reinforce two hydrogel constructs which were used as scaffold for hyaline cartilage regeneration. The gelation temperature and gelation time of hydrogel were analyzed by the rheometer and vial tilting method. Mechanical characterization was measured by uniaxial compression, indentation and dynamic mechanical analysis assay. Chondrocytes were then harvested from the knee joint of the New Zealand white rabbits and cultured in constructs. The cell proliferation, viability, production of glycosaminoglycans and collagen type II were assessed. The results showed that mechanical properties of the hydrogel were significantly enhanced when a hybrid with two layers of electrospun silk fibers was made. The results of GAG and collagen type II in cell-seeded scaffolds indicate support of the chondrogenic phenotype for chondrocytes with a significant increase in degummed silk fiber–hydrogel composite for GAG content and in two-layer electrospun fiber–hydrogel composite for Col II. It was concluded that these two modified scaffolds could be employed for cartilage tissue engineering. - Highlights: • Chitosan hydrogel composites fabricated by two forms of silk fiber • Silk fibers provide structural support for the hydrogel matrix. • The mechanical properties of hydrogel significantly improved by associating with silk. • Production of GAG and collagen type II was demonstrated within the scaffolds

  9. Enhanced mechanical properties of thermosensitive chitosan hydrogel by silk fibers for cartilage tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Mirahmadi, Fereshteh [Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); National Cell Bank of Iran, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of); Tafazzoli-Shadpour, Mohammad, E-mail: Tafazoli@aut.ac.ir [Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Shokrgozar, Mohammad Ali, E-mail: mashokrgozar@pasteur.ac.ir [National Cell Bank of Iran, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of); Bonakdar, Shahin [National Cell Bank of Iran, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of)

    2013-12-01

    Articular cartilage has limited repair capability following traumatic injuries and current methods of treatment remain inefficient. Reconstructing cartilage provides a new way for cartilage repair and natural polymers are often used as scaffold because of their biocompatibility and biofunctionality. In this study, we added degummed chopped silk fibers and electrospun silk fibers to the thermosensitive chitosan/glycerophosphate hydrogels to reinforce two hydrogel constructs which were used as scaffold for hyaline cartilage regeneration. The gelation temperature and gelation time of hydrogel were analyzed by the rheometer and vial tilting method. Mechanical characterization was measured by uniaxial compression, indentation and dynamic mechanical analysis assay. Chondrocytes were then harvested from the knee joint of the New Zealand white rabbits and cultured in constructs. The cell proliferation, viability, production of glycosaminoglycans and collagen type II were assessed. The results showed that mechanical properties of the hydrogel were significantly enhanced when a hybrid with two layers of electrospun silk fibers was made. The results of GAG and collagen type II in cell-seeded scaffolds indicate support of the chondrogenic phenotype for chondrocytes with a significant increase in degummed silk fiber–hydrogel composite for GAG content and in two-layer electrospun fiber–hydrogel composite for Col II. It was concluded that these two modified scaffolds could be employed for cartilage tissue engineering. - Highlights: • Chitosan hydrogel composites fabricated by two forms of silk fiber • Silk fibers provide structural support for the hydrogel matrix. • The mechanical properties of hydrogel significantly improved by associating with silk. • Production of GAG and collagen type II was demonstrated within the scaffolds.

  10. Cell-matrix mechanical interaction in electrospun polymeric scaffolds for tissue engineering: Implications for scaffold design and performance.

    Science.gov (United States)

    Kennedy, Kelsey M; Bhaw-Luximon, Archana; Jhurry, Dhanjay

    2017-03-01

    Engineered scaffolds produced by electrospinning of biodegradable polymers offer a 3D, nanofibrous environment with controllable structural, chemical, and mechanical properties that mimic the extracellular matrix of native tissues and have shown promise for a number of tissue engineering applications. The microscale mechanical interactions between cells and electrospun matrices drive cell behaviors including migration and differentiation that are critical to promote tissue regeneration. Recent developments in understanding these mechanical interactions in electrospun environments are reviewed, with emphasis on how fiber geometry and polymer structure impact on the local mechanical properties of scaffolds, how altering the micromechanics cues cell behaviors, and how, in turn, cellular and extrinsic forces exerted on the matrix mechanically remodel an electrospun scaffold throughout tissue development. Techniques used to measure and visualize these mechanical interactions are described. We provide a critical outlook on technological gaps that must be overcome to advance the ability to design, assess, and manipulate the mechanical environment in electrospun scaffolds toward constructs that may be successfully applied in tissue engineering and regenerative medicine. Tissue engineering requires design of scaffolds that interact with cells to promote tissue development. Electrospinning is a promising technique for fabricating fibrous, biomimetic scaffolds. Effects of electrospun matrix microstructure and biochemical properties on cell behavior have been extensively reviewed previously; here, we consider cell-matrix interaction from a mechanical perspective. Micromechanical properties as a driver of cell behavior has been well established in planar substrates, but more recently, many studies have provided new insights into mechanical interaction in fibrillar, electrospun environments. This review provides readers with an overview of how electrospun scaffold mechanics and

  11. Study of reciprocating engine with Z mechanism. Part 1. Discussion of effect on the performances of new concept engine; Yodo shiten riron wo mochiita ofuku do engine ni kansuru kenkyu. 1. Shinkihon kozo no donyu ni yoru seino kojo no suisatsu

    Energy Technology Data Exchange (ETDEWEB)

    Yoshizawa, Y; Fukuzaki, S; Kanno, M [Yoshiki Industrial Co. Ltd., Yamagata (Japan)

    1997-10-01

    A new reciprocating engine was developed as an application of new mechanism named as `Z mechanism.` In this new engine, the piston motion is described by a simple sine function and gives lower velocity around top dead center than that in conventional piston engines. Thus, the mode of combustion in this engine is closer to constant-volume process and gives higher thermal efficiency than ordinary engines. Use of Z-mechanism also eliminated high-order components of vibration that ordinary engines suffer. Development high-performance engine was successfully conducted with this new mechanism. 4 refs., 11 figs., 1 tab.

  12. Engineering on the straight and narrow: the mechanics of nanofibrous assemblies for fiber-reinforced tissue regeneration.

    Science.gov (United States)

    Mauck, Robert L; Baker, Brendon M; Nerurkar, Nandan L; Burdick, Jason A; Li, Wan-Ju; Tuan, Rocky S; Elliott, Dawn M

    2009-06-01

    Tissue engineering of fibrous tissues of the musculoskeletal system represents a considerable challenge because of the complex architecture and mechanical properties of the component structures. Natural healing processes in these dense tissues are limited as a result of the mechanically challenging environment of the damaged tissue and the hypocellularity and avascular nature of the extracellular matrix. When healing does occur, the ordered structure of the native tissue is replaced with a disorganized fibrous scar with inferior mechanical properties, engendering sites that are prone to re-injury. To address the engineering of such tissues, we and others have adopted a structurally motivated approach based on organized nanofibrous assemblies. These scaffolds are composed of ultrafine polymeric fibers that can be fabricated in such a way to recreate the structural anisotropy typical of fiber-reinforced tissues. This straight-and-narrow topography not only provides tailored mechanical properties, but also serves as a 3D biomimetic micropattern for directed tissue formation. This review describes the underlying technology of nanofiber production and focuses specifically on the mechanical evaluation and theoretical modeling of these structures as it relates to native tissue structure and function. Applying the same mechanical framework for understanding native and engineered fiber-reinforced tissues provides a functional method for evaluating the utility and maturation of these unique engineered constructs. We further describe several case examples where these principles have been put to test, and discuss the remaining challenges and opportunities in forwarding this technology toward clinical implementation.

  13. Engineering on the Straight and Narrow: The Mechanics of Nanofibrous Assemblies for Fiber-Reinforced Tissue Regeneration

    Science.gov (United States)

    Baker, Brendon M.; Nerurkar, Nandan L.; Burdick, Jason A.; Li, Wan-Ju; Tuan, Rocky S.; Elliott, Dawn M.

    2009-01-01

    Tissue engineering of fibrous tissues of the musculoskeletal system represents a considerable challenge because of the complex architecture and mechanical properties of the component structures. Natural healing processes in these dense tissues are limited as a result of the mechanically challenging environment of the damaged tissue and the hypocellularity and avascular nature of the extracellular matrix. When healing does occur, the ordered structure of the native tissue is replaced with a disorganized fibrous scar with inferior mechanical properties, engendering sites that are prone to re-injury. To address the engineering of such tissues, we and others have adopted a structurally motivated approach based on organized nanofibrous assemblies. These scaffolds are composed of ultrafine polymeric fibers that can be fabricated in such a way to recreate the structural anisotropy typical of fiber-reinforced tissues. This straight-and-narrow topography not only provides tailored mechanical properties, but also serves as a 3D biomimetic micropattern for directed tissue formation. This review describes the underlying technology of nanofiber production and focuses specifically on the mechanical evaluation and theoretical modeling of these structures as it relates to native tissue structure and function. Applying the same mechanical framework for understanding native and engineered fiber-reinforced tissues provides a functional method for evaluating the utility and maturation of these unique engineered constructs. We further describe several case examples where these principles have been put to test, and discuss the remaining challenges and opportunities in forwarding this technology toward clinical implementation. PMID:19207040

  14. Mechanics

    CERN Document Server

    Hartog, J P Den

    1961-01-01

    First published over 40 years ago, this work has achieved the status of a classic among introductory texts on mechanics. Den Hartog is known for his lively, discursive and often witty presentations of all the fundamental material of both statics and dynamics (and considerable more advanced material) in new, original ways that provide students with insights into mechanical relationships that other books do not always succeed in conveying. On the other hand, the work is so replete with engineering applications and actual design problems that it is as valuable as a reference to the practicing e

  15. Installation of Mechatronics Education Using the MindStorms for Dept. of Mechanical Engineering, O.N.C.T

    Directory of Open Access Journals (Sweden)

    Tatsushi Tokuyasu

    2009-09-01

    Full Text Available The author constructed an installation course of mechatronics and conducted on the students of department of mechanical engineering, Oita national college of technology. The course is composed of six sessions and is aiming to grow up the mechanical engineers who can adapt quickly to changes in industrial society. Then, the education programs of computer technology and information processing are more emphasized in this course. Certainly the specific subjects involved with mechatronics are constructed as a part of curriculum in the older grades, however there is some difficulties to make students of department of mechanical engineering to have interests in electronics and/or information science. Viewed in this light, it is better to begin mechatronics education with undergoing experiments like this course since they were in early grade.

  16. Installation of Mechatronics Education Using the MindStorms for Dept. of Mechanical Engineering, O.N.C.T

    Directory of Open Access Journals (Sweden)

    Tatsushi Tokuyasu

    2010-02-01

    Full Text Available The author constructed an installation course of mechatronics and conducted on the students of department of mechanical engineering, Oita national college of technology. The course is composed of six sessions and is aiming to grow up the mechanical engineers who can adapt quickly to changes in industrial society. Then, the education programs of computer technology and information processing are more emphasized in this course. Certainly the specific subjects involved with mechatronics are constructed as a part of curriculum in the older grades, however there is some difficulties to make students of department of mechanical engineering to have interests in electronics and/or information science. Viewed in this light, it is better to begin mechatronics education with undergoing experiments like this course since they were in early grade.

  17. Continuum theory of fibrous tissue damage mechanics using bond kinetics: application to cartilage tissue engineering.

    Science.gov (United States)

    Nims, Robert J; Durney, Krista M; Cigan, Alexander D; Dusséaux, Antoine; Hung, Clark T; Ateshian, Gerard A

    2016-02-06

    This study presents a damage mechanics framework that employs observable state variables to describe damage in isotropic or anisotropic fibrous tissues. In this mixture theory framework, damage is tracked by the mass fraction of bonds that have broken. Anisotropic damage is subsumed in the assumption that multiple bond species may coexist in a material, each having its own damage behaviour. This approach recovers the classical damage mechanics formulation for isotropic materials, but does not appeal to a tensorial damage measure for anisotropic materials. In contrast with the classical approach, the use of observable state variables for damage allows direct comparison of model predictions to experimental damage measures, such as biochemical assays or Raman spectroscopy. Investigations of damage in discrete fibre distributions demonstrate that the resilience to damage increases with the number of fibre bundles; idealizing fibrous tissues using continuous fibre distribution models precludes the modelling of damage. This damage framework was used to test and validate the hypothesis that growth of cartilage constructs can lead to damage of the synthesized collagen matrix due to excessive swelling caused by synthesized glycosaminoglycans. Therefore, alternative strategies must be implemented in tissue engineering studies to prevent collagen damage during the growth process.

  18. Mechanisms Underlying Cytotoxicity Induced by Engineered Nanomaterials: A Review of In Vitro Studies

    Science.gov (United States)

    Nogueira, Daniele R.; Mitjans, Montserrat; Rolim, Clarice M. B.; Vinardell, M. Pilar

    2014-01-01

    Engineered nanomaterials are emerging functional materials with technologically interesting properties and a wide range of promising applications, such as drug delivery devices, medical imaging and diagnostics, and various other industrial products. However, concerns have been expressed about the risks of such materials and whether they can cause adverse effects. Studies of the potential hazards of nanomaterials have been widely performed using cell models and a range of in vitro approaches. In the present review, we provide a comprehensive and critical literature overview on current in vitro toxicity test methods that have been applied to determine the mechanisms underlying the cytotoxic effects induced by the nanostructures. The small size, surface charge, hydrophobicity and high adsorption capacity of nanomaterial allow for specific interactions within cell membrane and subcellular organelles, which in turn could lead to cytotoxicity through a range of different mechanisms. Finally, aggregating the given information on the relationships of nanomaterial cytotoxic responses with an understanding of its structure and physicochemical properties may promote the design of biologically safe nanostructures. PMID:28344232

  19. Supersymmetric quantum mechanics: Engineered hierarchies of integrable potentials and related orthogonal polynomials

    International Nuclear Information System (INIS)

    Balondo Iyela, Daddy; Govaerts, Jan; Hounkonnou, M. Norbert

    2013-01-01

    Within the context of supersymmetric quantum mechanics and its related hierarchies of integrable quantum Hamiltonians and potentials, a general programme is outlined and applied to its first two simplest illustrations. Going beyond the usual restriction of shape invariance for intertwined potentials, it is suggested to require a similar relation for Hamiltonians in the hierarchy separated by an arbitrary number of levels, N. By requiring further that these two Hamiltonians be in fact identical up to an overall shift in energy, a periodic structure is installed in the hierarchy which should allow for its resolution. Specific classes of orthogonal polynomials characteristic of such periodic hierarchies are thereby generated, while the methods of supersymmetric quantum mechanics then lead to generalised Rodrigues formulae and recursion relations for such polynomials. The approach also offers the practical prospect of quantum modelling through the engineering of quantum potentials from experimental energy spectra. In this paper, these ideas are presented and solved explicitly for the cases N= 1 and N= 2. The latter case is related to the generalised Laguerre polynomials, for which indeed new results are thereby obtained. In the context of dressing chains and deformed polynomial Heisenberg algebras, some partial results for N⩾ 3 also exist in the literature, which should be relevant to a complete study of the N⩾ 3 general periodic hierarchies

  20. Supersymmetric quantum mechanics: Engineered hierarchies of integrable potentials and related orthogonal polynomials

    Energy Technology Data Exchange (ETDEWEB)

    Balondo Iyela, Daddy [International Chair in Mathematical Physics and Applications (ICMPA–UNESCO Chair), University of Abomey–Calavi, 072 B. P. 50 Cotonou, Republic of Benin (Benin); Centre for Cosmology, Particle Physics and Phenomenology (CP3), Institut de Recherche en Mathématique et Physique (IRMP), Université catholique de Louvain U.C.L., 2, Chemin du Cyclotron, B-1348 Louvain-la-Neuve (Belgium); Département de Physique, Université de Kinshasa (UNIKIN), B.P. 190 Kinshasa XI, Democratic Republic of Congo (Congo, The Democratic Republic of the); Govaerts, Jan [International Chair in Mathematical Physics and Applications (ICMPA–UNESCO Chair), University of Abomey–Calavi, 072 B. P. 50 Cotonou, Republic of Benin (Benin); Centre for Cosmology, Particle Physics and Phenomenology (CP3), Institut de Recherche en Mathématique et Physique (IRMP), Université catholique de Louvain U.C.L., 2, Chemin du Cyclotron, B-1348 Louvain-la-Neuve (Belgium); Hounkonnou, M. Norbert [International Chair in Mathematical Physics and Applications (ICMPA–UNESCO Chair), University of Abomey–Calavi, 072 B. P. 50 Cotonou, Republic of Benin (Benin)

    2013-09-15

    Within the context of supersymmetric quantum mechanics and its related hierarchies of integrable quantum Hamiltonians and potentials, a general programme is outlined and applied to its first two simplest illustrations. Going beyond the usual restriction of shape invariance for intertwined potentials, it is suggested to require a similar relation for Hamiltonians in the hierarchy separated by an arbitrary number of levels, N. By requiring further that these two Hamiltonians be in fact identical up to an overall shift in energy, a periodic structure is installed in the hierarchy which should allow for its resolution. Specific classes of orthogonal polynomials characteristic of such periodic hierarchies are thereby generated, while the methods of supersymmetric quantum mechanics then lead to generalised Rodrigues formulae and recursion relations for such polynomials. The approach also offers the practical prospect of quantum modelling through the engineering of quantum potentials from experimental energy spectra. In this paper, these ideas are presented and solved explicitly for the cases N= 1 and N= 2. The latter case is related to the generalised Laguerre polynomials, for which indeed new results are thereby obtained. In the context of dressing chains and deformed polynomial Heisenberg algebras, some partial results for N⩾ 3 also exist in the literature, which should be relevant to a complete study of the N⩾ 3 general periodic hierarchies.

  1. Relationship between micro-porosity, water permeability and mechanical behavior in scaffolds for cartilage engineering.

    Science.gov (United States)

    Vikingsson, L; Claessens, B; Gómez-Tejedor, J A; Gallego Ferrer, G; Gómez Ribelles, J L

    2015-08-01

    In tissue engineering the design and optimization of biodegradable polymeric scaffolds with a 3D-structure is an important field. The porous scaffold provide the cells with an adequate biomechanical environment that allows mechanotransduction signals for cell differentiation and the scaffolds also protect the cells from initial compressive loading. The scaffold have interconnected macro-pores that host the cells and newly formed tissue, while the pore walls should be micro-porous to transport nutrients and waste products. Polycaprolactone (PCL) scaffolds with a double micro- and macro-pore architecture have been proposed for cartilage regeneration. This work explores the influence of the micro-porosity of the pore walls on water permeability and scaffold compliance. A Poly(Vinyl Alcohol) with tailored mechanical properties has been used to simulate the growing cartilage tissue inside the scaffold pores. Unconfined and confined compression tests were performed to characterize both the water permeability and the mechanical response of scaffolds with varying size of micro-porosity while volume fraction of the macro-pores remains constant. The stress relaxation tests show that the stress response of the scaffold/hydrogel construct is a synergic effect determined by the performance of the both components. This is interesting since it suggests that the in vivo outcome of the scaffold is not only dependent upon the material architecture but also the growing tissue inside the scaffold׳s pores. On the other hand, confined compression results show that compliance of the scaffold is mainly controlled by the micro-porosity of the scaffold and less by hydrogel density in the scaffold pores. These conclusions bring together valuable information for customizing the optimal scaffold and to predict the in vivo mechanical behavior. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Manipulation of mechanical compliance of elastomeric PGS by incorporation of halloysite nanotubes for soft tissue engineering applications.

    Science.gov (United States)

    Chen, Qi-Zhi; Liang, Shu-Ling; Wang, Jiang; Simon, George P

    2011-11-01

    Poly (glycerol sebacate) (PGS) is a promising elastomer for use in soft tissue engineering. However, it is difficult to achieve with PGS a satisfactory balance of mechanical compliance and degradation rate that meet the requirements of soft tissue engineering. In this work, we have synthesised a new PGS nanocomposite system filled with halloysite nanotubes, and mechanical properties, as well as related chemical characters, of the nanocomposites were investigated. It was found that the addition of nanotubular halloysite did not compromise the extensibility of material, compared with the pure PGS counterpart; instead the elongation at rupture was increased from 110 (in the pure PGS) to 225% (in the 20 wt% composite). Second, Young's modulus and resilience of 3-5 wt% composites were ∼0.8 MPa and >94% respectively, remaining close to the level of pure PGS which is desired for applications in soft tissue engineering. Third, an important feature of the 1-5 wt% composites was their stable mechanical properties over an extended period, which could allow the provision of reliable mechanical support to damaged tissues during the lag phase of the healing process. Finally, the in vitro study indicated that the addition of halloysite slowed down the degradation rate of the composites. In conclusion, the good compliance, enhanced stretchability, stable mechanical behavior over an extended period, and reduced degradation rates make the 3-5 wt% composites promising candidates for application in soft tissue engineering. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. 78 FR 37885 - Approval of American Society of Mechanical Engineers' Code Cases

    Science.gov (United States)

    2013-06-24

    ... listed in these RGs as alternatives to engineering standards for the construction, inservice inspection... to engineering standards for the construction, ISI, and IST of nuclear power plant components. This...

  4. Hydrate failure in ITZ governs concrete strength: A micro-to-macro validated engineering mechanics model

    Czech Academy of Sciences Publication Activity Database

    Königsberger, M.; Hlobil, Michal; Delsaute, B.; Staquet, S.; Hellmich, C.; Pichler, B.

    2018-01-01

    Roč. 103, č. 1 (2018), s. 77-94 ISSN 0008-8846 Institutional support: RVO:68378297 Keywords : compressive strength * micromechanics * cement paste * concrete * modeling Subject RIV: JM - Building Engineering OBOR OECD: Construction engineering, Municipal and structural engineering Impact factor: 4.762, year: 2016 http://www.sciencedirect.com/science/article/pii/S0008884617302934?via%3Dihub

  5. Mechanically robust cryogels with injectability and bioprinting supportability for adipose tissue engineering.

    Science.gov (United States)

    Qi, Dianjun; Wu, Shaohua; Kuss, Mitchell A; Shi, Wen; Chung, Soonkyu; Deegan, Paul T; Kamenskiy, Alexey; He, Yini; Duan, Bin

    2018-05-26

    Bioengineered adipose tissues have gained increased interest as a promising alternative to autologous tissue flaps and synthetic adipose fillers for soft tissue augmentation and defect reconstruction in clinic. Although many scaffolding materials and biofabrication methods have been investigated for adipose tissue engineering in the last decades, there are still challenges to recapitulate the appropriate adipose tissue microenvironment, maintain volume stability, and induce vascularization to achieve long-term function and integration. In the present research, we fabricated cryogels consisting of methacrylated gelatin, methacrylated hyaluronic acid, and 4arm poly(ethylene glycol) acrylate (PEG-4A) by using cryopolymerization. The cryogels were repeatedly injectable and stretchable, and the addition of PEG-4A improved the robustness and mechanical properties. The cryogels supported human adipose progenitor cell (HWA) and adipose derived mesenchymal stromal cell adhesion, proliferation, and adipogenic differentiation and maturation, regardless of the addition of PEG-4A. The HWA laden cryogels facilitated the co-culture of human umbilical vein endothelial cells (HUVEC) and capillary-like network formation, which in return also promoted adipogenesis. We further combined cryogels with 3D bioprinting to generate handleable adipose constructs with clinically relevant size. 3D bioprinting enabled the deposition of multiple bioinks onto the cryogels. The bioprinted flap-like constructs had an integrated structure without delamination and supported vascularization. Adipose tissue engineering is promising for reconstruction of soft tissue defects, and also challenging for restoring and maintaining soft tissue volume and shape, and achieving vascularization and integration. In this study, we fabricated cryogels with mechanical robustness, injectability, and stretchability by using cryopolymerization. The cryogels promoted cell adhesion, proliferation, and adipogenic

  6. Engineering scale tests of mechanical disassembly and short stroke shearing systems for FBR fuel assembly

    International Nuclear Information System (INIS)

    Higuchi, Hidetoshi; Kitagaki, Toru; Koizumi, Kenji; Hirano, Hiroyasu; Takeuchi, Masayuki; Washiya, Tadahiro; Kawabe, Yukinari; Kobayashi, Tsuguyuki

    2011-01-01

    Japan Atomic Energy Agency (JAEA) and The Japan Atomic Power Company (JAPC) have been developing an advanced head-end process based on mechanical disassembly and short stroke shearing systems as a part of Fast Reactor Cycle Technology Development (FaCT). Fuel pins for a fast reactor are installed within a hexagonal shaped wrapper tube made of stainless steel. In order to reprocess the fast reactor fuel pins, they must be removed from the wrapper tube and transported to the shearing system without failure. In addition, the advanced aqueous reprocessing process, called 'NEXT' (New Extraction System for TRU Recovery) process requires a solution of the spent fuel with relatively high concentration (500g/L). JAEA and JAPC have developed the mechanical disassembly and the short stroke shearing technology which is expected to make fragmented fuel to satisfy these requirements. This paper reports the results of engineering scale tests on the mechanical disassembly and short stroke shearing systems. These tests were carried out with simulated FBR fuel assembly and removed pins. The mechanical cutting method has been developed to avoid fuel pin failure during disassembly operation. The cutting process is divided into two modes, so called 'slit-cut' for cutting the wrapper tube and 'crop-cut' for the end plug region of the fuel pin bundle. In the slit-cut mode, the depth of cutting was automatically controlled based on the calculated wastage of the cutting tool and deformation of the wrapper tube which had been measured before the cutting. This procedure was confirmed to minimize the fuel pin failure which was hard to prevent in the case of laser cutting. The cutting speed was also controlled automatically by the electric current of the cutting motor to lower the load of the cutting tool. The removed fuel pins were transported to the shearing machine, whose fuel shearing magazine width was set to be narrow to realize the suitable configuration for the short stroke shearing

  7. Investigation of Deposit Formation Mechanisms for Engine In-cylinder Combustion and Exhaust Systems Using Quantitative Analysis and Sustainability Study

    Science.gov (United States)

    Ye, Z.; Meng, Q.; Mohamadian, H. P.; Wang, J. T.; Chen, L.; Zhu, L.

    2007-06-01

    The formation of SI engine combustion deposits is a complex phenomenon which depends on various factors of fuel, oil, additives, and engine. The goal of this study is to examine the effects of operating conditions, gasoline, lubricating oil, and additives on deposit formation. Both an experimental investigation and theoretical analysis are conducted on a single cylinder engine. As a result, the impact of deposits on engine performance and exhaust emissions (HC, NO x ) has been indicated. Using samples from a cylinder head and exhaust pipe as well as switching gases via the dual-gas method (N2, O2), the deposit formation mechanism is thoroughly investigated via the thermogravity analysis approach, where the roles of organic, inorganic, and volatile components of fuel, additives, and oil on deposit formation are identified from thermogravity curves. Sustainable feedback control design is then proposed for potential emission control and performance optimization

  8. Teaching design in the first years of a traditional mechanical engineering degree: methods, issues and future perspectives

    Science.gov (United States)

    Silva, Arlindo; Fontul, Mihail; Henriques, Elsa

    2015-01-01

    Engineering design is known as an answer to an ill-defined problem. As any answer to an ill-defined problem, it can never be completely right or absolutely wrong. The methods that universities use to teach engineering design, as a consequence of this, suffer from the same fate. However, the accumulated experience with the 'chalk and talk' teaching tradition has led to a reality in which the employers of fresh graduates are not happy with the engineers they are getting. Part of their complaints are related with the inability of recently graduate engineers to work in problems where the boundaries are not well defined, are interdisciplinary, require the use of effective communication and integrate non-technical issues. These skills are mostly absent from traditional engineering curricula. This paper demonstrates the implementation of engineering design perspectives enhancing some of the aforementioned skills in a traditional mechanical engineering curriculum. It emphasises in particular a design project that is tackled in a sequence of conventional courses with a focus that depends on the course objectives and disciplinary domain. This transdisciplinary design project conveys the idea (and effectively implements it concurrently) that design is multidisciplinary.

  9. Completing the results of the 2013 Boston marathon.

    Directory of Open Access Journals (Sweden)

    Dorit Hammerling

    Full Text Available The 2013 Boston marathon was disrupted by two bombs placed near the finish line. The bombs resulted in three deaths and several hundred injuries. Of lesser concern, in the immediate aftermath, was the fact that nearly 6,000 runners failed to finish the race. We were approached by the marathon's organizers, the Boston Athletic Association (BAA, and asked to recommend a procedure for projecting finish times for the runners who could not complete the race. With assistance from the BAA, we created a dataset consisting of all the runners in the 2013 race who reached the halfway point but failed to finish, as well as all runners from the 2010 and 2011 Boston marathons. The data consist of split times from each of the 5 km sections of the course, as well as the final 2.2 km (from 40 km to the finish. The statistical objective is to predict the missing split times for the runners who failed to finish in 2013. We set this problem in the context of the matrix completion problem, examples of which include imputing missing data in DNA microarray experiments, and the Netflix prize problem. We propose five prediction methods and create a validation dataset to measure their performance by mean squared error and other measures. The best method used local regression based on a K-nearest-neighbors algorithm (KNN method, though several other methods produced results of similar quality. We show how the results were used to create projected times for the 2013 runners and discuss potential for future application of the same methodology. We present the whole project as an example of reproducible research, in that we are able to make the full data and all the algorithms we have used publicly available, which may facilitate future research extending the methods or proposing completely different approaches.

  10. Completing the results of the 2013 Boston marathon.

    Science.gov (United States)

    Hammerling, Dorit; Cefalu, Matthew; Cisewski, Jessi; Dominici, Francesca; Parmigiani, Giovanni; Paulson, Charles; Smith, Richard L

    2014-01-01

    The 2013 Boston marathon was disrupted by two bombs placed near the finish line. The bombs resulted in three deaths and several hundred injuries. Of lesser concern, in the immediate aftermath, was the fact that nearly 6,000 runners failed to finish the race. We were approached by the marathon's organizers, the Boston Athletic Association (BAA), and asked to recommend a procedure for projecting finish times for the runners who could not complete the race. With assistance from the BAA, we created a dataset consisting of all the runners in the 2013 race who reached the halfway point but failed to finish, as well as all runners from the 2010 and 2011 Boston marathons. The data consist of split times from each of the 5 km sections of the course, as well as the final 2.2 km (from 40 km to the finish). The statistical objective is to predict the missing split times for the runners who failed to finish in 2013. We set this problem in the context of the matrix completion problem, examples of which include imputing missing data in DNA microarray experiments, and the Netflix prize problem. We propose five prediction methods and create a validation dataset to measure their performance by mean squared error and other measures. The best method used local regression based on a K-nearest-neighbors algorithm (KNN method), though several other methods produced results of similar quality. We show how the results were used to create projected times for the 2013 runners and discuss potential for future application of the same methodology. We present the whole project as an example of reproducible research, in that we are able to make the full data and all the algorithms we have used publicly available, which may facilitate future research extending the methods or proposing completely different approaches.

  11. A thermodynamic approach to compare the performance of rhombic-drive and crank-drive mechanisms for a beta-type Stirling engine

    International Nuclear Information System (INIS)

    Aksoy, F.; Solmaz, H.; Karabulut, H.; Cinar, C.; Ozgoren, Y.O.; Polat, Seyfi

    2016-01-01

    Highlights: • Rhombic drive and crank drive mechanisms of a beta type engine were compared. • Nodal analysis method was used to compare engines having different drive mechanism. • Maximum specific power was 1410 W/L for rhombic-drive engine. • Heat transfer coefficient was determined as 475 W/m"2K for rhombic-drive engine. • Rhombic drive provided higher efficiency because of its better kinematic behaviours. - Abstract: In this study, the effect of rhombic drive and crank drive mechanisms on the performance of a beta-type Stirling engine was investigated by nodal analysis. Kinematic and thermodynamic relations for both drive mechanisms were introduced and a Fortran code was written for the solution. Piston strokes, cylinder and displacer diameters, hot and cold end temperatures, regenerator volumes and heat transfer surface areas were taken equal for both engines with two different drive mechanisms. In the analysis, air was used as the working gas. Engine power and efficiency were compared for different charge pressure values, working gas mass values, heat transfer coefficients and hot end temperatures. Maximum specific engine power was 1410 W/L for the engine with rhombic drive mechanism and 1200 W/L for the engine with crank drive mechanism at 4 bars of charge pressure and 500 W/m"2K heat transfer coefficient. Rhombic drive mechanism was relatively advantageous at low working gas mass values and high hot end temperatures. In comparison with the engine having rhombic drive mechanism, the relatively poor kinematic behaviour of the engine having crank drive mechanism caused lower engine efficiency and performance. Heat transfer coefficient was also predicted by using an experimental pressure trace.

  12. Mechanical Stimulation of Adipose-Derived Stem Cells for Functional Tissue Engineering of the Musculoskeletal System via Cyclic Hydrostatic Pressure, Simulated Microgravity, and Cyclic Tensile Strain.

    Science.gov (United States)

    Nordberg, Rachel C; Bodle, Josie C; Loboa, Elizabeth G

    2018-01-01

    It is critical that human adipose stem cell (hASC) tissue-engineering therapies possess appropriate mechanical properties in order to restore function of the load bearing tissues of the musculoskeletal system. In an effort to elucidate the hASC response to mechanical stimulation and develop mechanically robust tissue engineered constructs, recent research has utilized a variety of mechanical loading paradigms including cyclic tensile strain, cyclic hydrostatic pressure, and mechanical unloading in simulated microgravity. This chapter describes methods for applying these mechanical stimuli to hASC to direct differentiation for functional tissue engineering of the musculoskeletal system.

  13. A compact skeletal mechanism for n -dodecane with optimized semi-global low-temperature chemistry for diesel engine simulations

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Tong; Pei, Yuanjiang; Zhong, Bei-Jing; Som, Sibendu; Lu, Tianfeng; Luo, Kai Hong

    2017-03-01

    A skeletal mechanism with 54 species and 269 reactions was developed to predict pyrolysis and oxidation of n-dodecane as a diesel fuel surrogate involving both high-temperature (high-T) and low-temperature (low-T) conditions. The skeletal mechanism was developed from a semi-detailed mechanism developed at the University of Southern California (USC). Species and reactions for high-T pyrolysis and oxidation of C5-C12 were reduced by using reaction flow analysis (RFA), isomer lumping, and then merged into a skeletal C0-C4 core to form a high-T sub-mechanism. Species and lumped semi-global reactions for low-T chemistry were then added to the high-T sub-mechanism and a 54-species skeletal mechanism is obtained. The rate parameters of the low-T reactions were tuned against a detailed mechanism by the Lawrence Livermore National Laboratory (LLNL), as well as the Spray A flame experimental data, to improve the prediction of ignition delay at low-T conditions, while the high-T chemistry remained unchanged. The skeletal mechanism was validated for auto-ignition, perfectly stirred reactors (PSR), flow reactors and laminar premixed flames over a wide range of flame conditions. The skeletal mechanism was then employed to simulate three-dimensional turbulent spray flames at compression ignition engine conditions and validated against experimental data from the Engine Combustion Network (ECN).

  14. Boston City Hospital and the Thorndike Memorial Laboratory: the birth of modern haematology.

    Science.gov (United States)

    Elrod, Jeffrey M; Karnad, Anand B

    2003-05-01

    Established in 1923, the Thorndike Memorial Laboratory at Boston City Hospital was the first clinical research laboratory in a municipal hospital in the United States of America. Minot and Castle, who were the second and third directors of the Laboratory, were pioneer haematologists and clinical investigators of the highest calibre who created an atmosphere at the Laboratory that would foster patient-centred research and attract the best physician-scientists to work and train there. The haematology research division of the Laboratory made important original contributions to the understanding of the pathophysiology of anaemia, the mechanisms of red cell and platelet destruction and the phagocytic role of the spleen, the nature of haemoglobin (normal and sickle cell), the nature of haemophilia and its therapy and the early classification of lymphoma. It contributed to the Thorndike Memorial Laboratory's worldwide reputation as a model research laboratory and established its reputation as the birthplace of modern haematology.

  15. A Danish adaptation of the Boston Naming Test

    DEFF Research Database (Denmark)

    Jørgensen, Kasper; Johannsen, Peter; Vogel, Asmus

    2017-01-01

    Objective: The purpose of the present study was to develop a Danish adaptation of the Boston Naming Test (BNT) including a shortened 30-item version of the BNT for routine clinical use and two parallel 15-item versions for screening purposes. Method: The Danish adaptation of the BNT was based...... on ranking of items according to difficulty in a sample of older non-patients (n = 99). By selecting those items with the largest discrepancy in difficulty for non-patients compared to a mild Alzheimer’s disease (AD) sample (n = 53), the shortened versions of the BNT were developed. Using an overlapping...

  16. Boston Community Information System 1986 Experimental Test Results.

    Science.gov (United States)

    1987-08-01

    addicted partiipat.’ - 1031 ’Questions concerning application and cost’ - 1032 Of would like to have different background/foreground colors .... I am getting...admit I am an ’info junkie.’ I am addicted to Boston CommlnS. It has become so much apart of my dafl routine that the isses of the other 14 magazines and...8217Sports, Financial* - 106 eSports , Racing’ -1101 -Sports- - 1107 aStocks, sportas - 1109 aStocks’ - 1110 OFinascial, commercials - 1111 *sports

  17. Validation of the Boston Carpal Tunnel Questionnaire in Russia

    Directory of Open Access Journals (Sweden)

    D. G. Yusupova

    2018-01-01

    Full Text Available International scales and questionnaires have become widespread in Russian neurology. Validation is a procedure of top priority necessary before applying this kind of diagnostic instrument in Russian-speaking population. In this article, validation of the Boston Carpal Tunnel Questionnaire (BCTQ intended for patients with this disease is described. Use of validated Russian version would allow to objectively evaluate severity of clinical manifestations of carpal tunnel syndrome and follow patient dynamics. We present the official BCTQ version recommended for use in Russia, as well as data that showed high sensitivity and reliability of this instrument for clinical evaluation of carpal tunnel syndrome.

  18. Introducing a flipped classroom to engineering students: A case study in mechanics of materials course

    Science.gov (United States)

    Suwapaet, Nuchida

    2018-03-01

    Flipped classroom is basically a reversed way of learning in classroom. Lecture is brought outside classroom and available online in many forms such as video lecture and e-books. In-class time is focused more on discussions and practices such as exercises and projects. Flipped classroom was introduced to Mechanical Engineering students in Mechanics of Materials course in 2016 academic year at Mahasarakham University, Thailand. The course was still taught in traditional way and series of video lecture were used as additional class materials outside classroom. There were 2 groups of students that enrolled in the course in 2 different semesters. Students in 1st semester were taught in traditional way (control group) and students in 2nd semester were used flipped classroom (experiment group). Students' grades between 2 groups were compared and analyzed. Satisfaction survey of using flipped classroom was carried out and evaluated. There were 3 aspects of evaluation which were content, varieties of activity, and functions. Results showed that the course's GPA of experiment group was 1.92 which was greater than the control group of 1.68. The greatly reduction of failed students in experiment group was noticeable. The percentages of failed students of control and experiment groups were 17% and 6%. Satisfaction survey evaluation results showed that the students satisfied in high level in every aspect. The comments pointed out that flipped classroom were easy to use and promoted self-study outside classroom. Those qualities would help students develop more skills in lifelong learning and learning to learn.

  19. The Influence of Bioreactor Geometry and the Mechanical Environment on Engineered Tissues

    KAUST Repository

    Osborne, J. M.; O’ Dea, R. D.; Whiteley, J. P.; Byrne, H. M.; Waters, S. L.

    2010-01-01

    A three phase model for the growth of a tissue construct within a perfusion bioreactor is examined. The cell population (and attendant extracellular matrix), culture medium, and porous scaffold are treated as distinct phases. The bioreactor system is represented by a two-dimensional channel containing a cell-seeded rigid porous scaffold (tissue construct), which is perfused with a culture medium. Through the prescription of appropriate functional forms for cell proliferation and extracellular matrix deposition rates, the model is used to compare the influence of cell density-, pressure-, and culture medium shear stress-regulated growth on the composition of the engineered tissue. The governing equations are derived in O'Dea et al. "A Three Phase Model for Tissue Construct Growth in a Perfusion Bioreactor," Math. Med. Biol., in which the long-wavelength limit was exploited to aid analysis; here, finite element methods are used to construct two-dimensional solutions to the governing equations and to investigate thoroughly their behavior. Comparison of the total tissue yield and averaged pressures, velocities, and shear stress demonstrates that quantitative agreement between the two-dimensional and long-wavelength approximation solutions is obtained for channel aspect ratios of order 10 -2 and that much of the qualitative behavior of the model is captured in the long-wavelength limit, even for relatively large channel aspect ratios. However, we demonstrate that in order to capture accurately the effect of mechanotransduction mechanisms on tissue construct growth, spatial effects in at least two dimensions must be included due to the inherent spatial variation of mechanical stimuli relevant to perfusion bioreactors, most notably, fluid shear stress, a feature not captured in the long-wavelength limit. Copyright © 2010 by ASME.

  20. Enhanced organic contaminants accumulation in crops: Mechanisms, interactions with engineered nanomaterials in soil.

    Science.gov (United States)

    Wu, Xiang; Wang, Wei; Zhu, Lizhong

    2018-05-02

    The mechanism of enhanced accumulation of organic contaminants in crops with engineered nanomaterials (ENMs) were investigated by co-exposure of crops (Ipomoea aquatica Forsk (Swamp morning-glory), Cucumis sativus L. (cucumber), Zea mays L. (corn), Spinacia oleracea L. (spinach) and Cucurbita moschata (pumpkin))to a range of chemicals (polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polybrominated diphenyl ether (PBDE)) and ENMs (TiO 2 , Ag, Al 2 O 3 , graphene, carbon nanotubes (CNTs)) in soil. Induced by 50 mg kg -1 graphene co-exposure, the increase range of BDE-209, BaP, p,p'-DDE, HCB, PYR, FLU, ANT, and PHEN in the plants were increased in the range of 7.51-36.42, 5.69-32.77, 7.09-59.43, 11.61-66.73, 4.58-57.71, 5.79-109.07, 12.85-109.76, and15.57-127.75 ng g -1 , respectively. The contaminants in ENMs-spiked and control soils were separated into bioavailable, bound and residual fractions using a sequential ultrasonic extraction procedure (SUEP) to investigate the mechanism of the enhanced accumulation. The bioavailable fraction in spiked soils showed no significant difference (p > 0.05) from that in the control, while the bound fraction increased in equal proportion (p > 0.05) to the reduction in the residual fraction. These results implied that ENMs can competitively adsorbed the bound of organic contaminants from soil and co-transferred into crops, followed by a portion of the residual fraction transferred to the bound fraction to maintain the balance of different fractions in soils. The mass balance was all higher than 98.5%, indicating the portion of degraded contaminants was less than 1.5%. These findings could expand our knowledge about the organic contaminants accumulation enhancement in crops with ENMs. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. The Influence of Bioreactor Geometry and the Mechanical Environment on Engineered Tissues

    KAUST Repository

    Osborne, J. M.

    2010-01-01

    A three phase model for the growth of a tissue construct within a perfusion bioreactor is examined. The cell population (and attendant extracellular matrix), culture medium, and porous scaffold are treated as distinct phases. The bioreactor system is represented by a two-dimensional channel containing a cell-seeded rigid porous scaffold (tissue construct), which is perfused with a culture medium. Through the prescription of appropriate functional forms for cell proliferation and extracellular matrix deposition rates, the model is used to compare the influence of cell density-, pressure-, and culture medium shear stress-regulated growth on the composition of the engineered tissue. The governing equations are derived in O\\'Dea et al. "A Three Phase Model for Tissue Construct Growth in a Perfusion Bioreactor," Math. Med. Biol., in which the long-wavelength limit was exploited to aid analysis; here, finite element methods are used to construct two-dimensional solutions to the governing equations and to investigate thoroughly their behavior. Comparison of the total tissue yield and averaged pressures, velocities, and shear stress demonstrates that quantitative agreement between the two-dimensional and long-wavelength approximation solutions is obtained for channel aspect ratios of order 10 -2 and that much of the qualitative behavior of the model is captured in the long-wavelength limit, even for relatively large channel aspect ratios. However, we demonstrate that in order to capture accurately the effect of mechanotransduction mechanisms on tissue construct growth, spatial effects in at least two dimensions must be included due to the inherent spatial variation of mechanical stimuli relevant to perfusion bioreactors, most notably, fluid shear stress, a feature not captured in the long-wavelength limit. Copyright © 2010 by ASME.

  2. Mississippi Curriculum Framework for Diesel Equipment Repair & Service (Program CIP: 47.0605--Diesel Engine Mechanic & Repairer). Secondary Programs.

    Science.gov (United States)

    Mississippi Research and Curriculum Unit for Vocational and Technical Education, State College.

    This document, which reflects Mississippi's statutory requirement that instructional programs be based on core curricula and performance-based assessment, contains outlines of the instructional units required in local instructional management plans and daily lesson plans for diesel engine mechanics I and II. Presented first are a program…

  3. Influence of the temporal deposition of extracellular matrix on the mechanical properties of tissue-engineered cartilage

    NARCIS (Netherlands)

    Khoshgoftar, M.; Wilson, W.; Ito, K.; Donkelaar, van C.C.

    2014-01-01

    Enhancement of the load-bearing capacity of tissue engineered (TE) cartilage is expected to improve the clinical outcome of implantations. Generally, cartilage TE studies aim to increase the total extracellular matrix (ECM) content to improve implant mechanical properties. Besides the ECM content,

  4. Mechanical Engineering at KSC: 'How I spend My Hours from 9 to 5 and Draw a Paycheck'

    Science.gov (United States)

    Randazzo, John; Steinrock. Todd (Technical Monitor)

    2003-01-01

    This viewgraph presentation provides an overview of a senior mechanical engineer's role in designing and testing sensors to fly aboard the shuttle Discovery during STS-95 and STS-98. Topics covered include: software development tools, computation fluid dynamics, structural analysis, housing design, and systems integration.

  5. Development and Validation of Mechanical Engineering Trade Skills Assessment Instrument for Sustainable Job Security in Yobe State

    Science.gov (United States)

    Adamu, Gishua Garba; Dawha, Josphine Musa; Kamar, Tiamiyu Salihu

    2015-01-01

    Mechanical Engineering Trade Skills Assessment Instrument (METSAI) is aimed at determining the extent to which students have acquired practical skills before graduation that will enable them get employment for sustainable job security in Yobe state. The study employed instrumentation research design. The populations of the study were 23 mechanical…

  6. Escapement mechanisms and the conversion of disequilibria; the engines of creation

    Energy Technology Data Exchange (ETDEWEB)

    Branscomb, E., E-mail: brnscmb@illinois.edu [Institute for Genomic Biology, UIUC, Champaign–Urbana, IL (United States); NASA Astrobiology Institute, UIUC NAI, Towards Universal Biology (United States); Biancalani, T. [Institute for Genomic Biology, UIUC, Champaign–Urbana, IL (United States); NASA Astrobiology Institute, UIUC NAI, Towards Universal Biology (United States); Department of Physics, Massachusetts Institute of Technology, Cambridge (United States); Goldenfeld, N. [Institute for Genomic Biology, UIUC, Champaign–Urbana, IL (United States); NASA Astrobiology Institute, UIUC NAI, Towards Universal Biology (United States); Russell, M. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA (United States); NASA Astrobiology Institute, JPL Icy Worlds (United States)

    2017-03-17

    Virtually every interesting natural phenomenon, not least life itself, entails physical systems being forced to flow thermodynamically up-hill, away from equilibrium rather than towards it. This requires the action of a mechanism, acting as an “engine”, which lashes the up-hill process to a more powerful one proceeding in its spontaneous, down-hill direction; in this way converting one disequilibrium into another. All organized and dynamic elements of creation, from the galactic to the atomic, can be viewed as powered by, or being the result of, engines of disequilibria conversion; each a link in a great hierarchical cascade of conversions. There is, however, widespread misunderstanding about how disequilibria conversions happen–and indeed about what physically causes them to happen–especially regarding the role of energy and of the physical meaning of free energy. We attempt here to describe and justify what we assert is the correct alternative view of how phenomena are powered in nature, focusing especially on the molecular-level conversion processes (often called “energy conserving”) that power life and that must, then acting in an entirely abiotic context, have driven it first into being.

  7. Development and use of data base on mechanical properties of materials in power engineering

    International Nuclear Information System (INIS)

    Popov, A.A.; Shchukina, E.G.; Karaev, A.B.

    1987-01-01

    The structure of a data base on the properties of materials used in reactor engineering is considered. The data base presents a factographic automated data retrieval system, containing test results on the 15Kh2NMFA, 15Kh2NMFA-A, 15Kh2MFA, 10GN2MFA, 22K reactor vessel steels and also the data on the A533, A508 and A304 steels taken from literature. The system is realized using the VAN6 minicomputer and operates in a dialogue mode. Software of the system is arranged by module scheme and realized using the BASIC language. Results of tensile, impact, hardness, fatigue, brittle hardness, radiation resistance, high-temperature strength and heat-resistance tests and data on the thermal properties of the alloys are introduced into the system. Prior to the input in the system the information is subjected to additional expert analysis for completeness and authenticity. The main function of the data base considered consists in the systematization of a large volume of experimental data, which envisages arbitrary retrieval and subsequent analysis using statistical methods. The system contains approximately 15 thousand records on magnetic discs. The total volume of the store is 20 M byte. The system capabilities are demonstrated when analyzing the effects of aalloying additions on mechanical properties of the 15Kh2NMFA steel

  8. Training mechanical engineering students to utilize biological inspiration during product development.

    Science.gov (United States)

    Bruck, Hugh A; Gershon, Alan L; Golden, Ira; Gupta, Satyandra K; Gyger, Lawrence S; Magrab, Edward B; Spranklin, Brent W

    2007-12-01

    The use of bio-inspiration for the development of new products and devices requires new educational tools for students consisting of appropriate design and manufacturing technologies, as well as curriculum. At the University of Maryland, new educational tools have been developed that introduce bio-inspired product realization to undergraduate mechanical engineering students. These tools include the development of a bio-inspired design repository, a concurrent fabrication and assembly manufacturing technology, a series of undergraduate curriculum modules and a new senior elective in the bio-inspired robotics area. This paper first presents an overview of the two new design and manufacturing technologies that enable students to realize bio-inspired products, and describes how these technologies are integrated into the undergraduate educational experience. Then, the undergraduate curriculum modules are presented, which provide students with the fundamental design and manufacturing principles needed to support bio-inspired product and device development. Finally, an elective bio-inspired robotics project course is present, which provides undergraduates with the opportunity to demonstrate the application of the knowledge acquired through the curriculum modules in their senior year using the new design and manufacturing technologies.

  9. Cross-linkable graphene oxide embedded nanocomposite hydrogel with enhanced mechanics and cytocompatibility for tissue engineering.

    Science.gov (United States)

    Liu, Xifeng; Miller, A Lee; Waletzki, Brian E; Lu, Lichun

    2018-05-01

    Graphene oxide (GO) is an attractive material that can be utilized to enhance the modulus and conductivities of substrates and hydrogels. To covalently cross-link graphene oxide sheets into hydrogels, abundant cross-linkable double bonds were introduced to synthesize the graphene-oxide-tris-acrylate sheet (GO-TrisA). Polyacrylamide (PAM) nanocomposite hydrogels were then fabricated with inherent covalently and permanently cross-linked GO-TrisA sheets. Results showed that the covalently cross-linked GO-TrisA/PAM nanocomposite hydrogel had enhanced mechanical strength, thermo stability compared with GO/PAM hydrogel maintained mainly by hydrogen bonding between PAM chains and GO sheets. In vitro cell study showed that the covalently cross-linked rGO-TrisA/PAM nanocomposite hydrogel had excellent cytocompatibility after in situ reduction. These results suggest that rGO-TrisA/PAM nanocomposite hydrogel holds great potential for tissue engineering applications. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1247-1257, 2018. © 2018 Wiley Periodicals, Inc.

  10. Aerosol in selected laboratories at Faculty of Mechanical Engineering, Opole University of Technology

    Science.gov (United States)

    Olszowski, Tomasz

    2017-10-01

    The paper contains the results of a study into mass concentration of the dispersed aerosol fraction with the aerodynamic diameter of up to 2.5 and 10 micrometers. The study was conducted during classes with students participating in them in two laboratories located at Faculty of Mechanical Engineering, Opole University of Technology as well as outdoor outside the building. It was demonstrated that the values of the mass concentration of PM2.5 and PM10 measured in the laboratories differ considerably from the levels measured in the ambient air in the outdoor areas surrounding the faculty building. It was concluded that the diversity of PM2.5/PM10 ratio was greater in the laboratories. Direct correlation was not established between the concentrations of the particular PM fractions in the two investigated environments. It was demonstrated that there is a statistically significant relation between the concentration of PM2.5 and PM10 and the number of people present in the laboratory. The conducted cluster analysis led to the detection of the existence of dominant structures determining air quality parameters. For the analyzed case, endogenic factors are responsible for the aerosanitary condition. The study demonstrated that the evaluation of air quality needs to be performed individually for the specific rooms.

  11. Bio-Orthogonally Crosslinked, Engineered Protein Hydrogels with Tunable Mechanics and Biochemistry for Cell Encapsulation.

    Science.gov (United States)

    Madl, Christopher M; Katz, Lily M; Heilshorn, Sarah C

    2016-06-07

    Covalently-crosslinked hydrogels are commonly used as 3D matrices for cell culture and transplantation. However, the crosslinking chemistries used to prepare these gels generally cross-react with functional groups present on the cell surface, potentially leading to cytotoxicity and other undesired effects. Bio-orthogonal chemistries have been developed that do not react with biologically relevant functional groups, thereby preventing these undesirable side reactions. However, previously developed biomaterials using these chemistries still possess less than ideal properties for cell encapsulation, such as slow gelation kinetics and limited tuning of matrix mechanics and biochemistry. Here, engineered elastin-like proteins (ELPs) are developed that cross-link via strain-promoted azide-alkyne cycloaddition (SPAAC) or Staudinger ligation. The SPAAC-crosslinked materials form gels within seconds and complete gelation within minutes. These hydrogels support the encapsulation and phenotypic maintenance of human mesenchymal stem cells, human umbilical vein endothelial cells, and murine neural progenitor cells. SPAAC-ELP gels exhibit independent tuning of stiffness and cell adhesion, with significantly improved cell viability and spreading observed in materials containing a fibronectin-derived arginine-glycine-aspartic acid (RGD) domain. The crosslinking chemistry used permits further material functionalization, even in the presence of cells and serum. These hydrogels are anticipated to be useful in a wide range of applications, including therapeutic cell delivery and bioprinting.

  12. An Engineered Kinetic Amplification Mechanism for Single Nucleotide Variant Discrimination by DNA Hybridization Probes.

    Science.gov (United States)

    Chen, Sherry Xi; Seelig, Georg

    2016-04-20

    Even a single-nucleotide difference between the sequences of two otherwise identical biological nucleic acids can have dramatic functional consequences. Here, we use model-guided reaction pathway engineering to quantitatively improve the performance of selective hybridization probes in recognizing single nucleotide variants (SNVs). Specifically, we build a detection system that combines discrimination by competition with DNA strand displacement-based catalytic amplification. We show, both mathematically and experimentally, that the single nucleotide selectivity of such a system in binding to single-stranded DNA and RNA is quadratically better than discrimination due to competitive hybridization alone. As an additional benefit the integrated circuit inherits the property of amplification and provides at least 10-fold better sensitivity than standard hybridization probes. Moreover, we demonstrate how the detection mechanism can be tuned such that the detection reaction is agnostic to the position of the SNV within the target sequence. in contrast, prior strand displacement-based probes designed for kinetic discrimination are highly sensitive to position effects. We apply our system to reliably discriminate between different members of the let-7 microRNA family that differ in only a single base position. Our results demonstrate the power of systematic reaction network design to quantitatively improve biotechnology.

  13. A Novel Visual Interface to Foster Innovation in Mechanical Engineering and Protect from Patent Infringement

    Science.gov (United States)

    Sorce, Salvatore; Malizia, Alessio; Jiang, Pingfei; Atherton, Mark; Harrison, David

    2018-04-01

    One of the main time and money consuming tasks in the design of industrial devices and parts is the checking of possible patent infringements. Indeed, the great number of documents to be mined and the wide variety of technical language used to describe inventions are reasons why considerable amounts of time may be needed. On the other hand, the early detection of a possible patent conflict, in addition to reducing the risk of legal disputes, could stimulate a designers’ creativity to overcome similarities in overlapping patents. For this reason, there are a lot of existing patent analysis systems, each with its own features and access modes. We have designed a visual interface providing an intuitive access to such systems, freeing the designers from the specific knowledge of querying languages and providing them with visual clues. We tested the interface on a framework aimed at representing mechanical engineering patents; the framework is based on a semantic database and provides patent conflict analysis for early-stage designs. The interface supports a visual query composition to obtain a list of potentially overlapping designs.

  14. Mechanical properties of electrospun bilayer fibrous membranes as potential scaffolds for tissue engineering.

    Science.gov (United States)

    Pu, Juan; Komvopoulos, Kyriakos

    2014-06-01

    Bilayer fibrous membranes of poly(l-lactic acid) (PLLA) were fabricated by electrospinning, using a parallel-disk mandrel configuration that resulted in the sequential deposition of a layer with fibers aligned across the two parallel disks and a layer with randomly oriented fibers, both layers deposited in a single process step. Membrane structure and fiber alignment were characterized by scanning electron microscopy and two-dimensional fast Fourier transform. Because of the intricacies of the generated electric field, bilayer membranes exhibited higher porosity than single-layer membranes consisting of randomly oriented fibers fabricated with a solid-drum collector. However, despite their higher porosity, bilayer membranes demonstrated generally higher elastic modulus, yield strength and toughness than single-layer membranes with random fibers. Bilayer membrane deformation at relatively high strain rates comprised multiple abrupt microfracture events characterized by discontinuous fiber breakage. Bilayer membrane elongation yielded excessive necking of the layer with random fibers and remarkable fiber stretching (on the order of 400%) in the layer with fibers aligned in the stress direction. In addition, fibers in both layers exhibited multiple localized necking, attributed to the nonuniform distribution of crystalline phases in the fibrillar structure. The high membrane porosity, good mechanical properties, and good biocompatibility and biodegradability of PLLA (demonstrated in previous studies) make the present bilayer membranes good scaffold candidates for a wide range of tissue engineering applications. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  15. Mechanical properties and biocompatibility of porous titanium scaffolds for bone tissue engineering.

    Science.gov (United States)

    Chen, Yunhui; Frith, Jessica Ellen; Dehghan-Manshadi, Ali; Attar, Hooyar; Kent, Damon; Soro, Nicolas Dominique Mathieu; Bermingham, Michael J; Dargusch, Matthew S

    2017-11-01

    Synthetic scaffolds are a highly promising new approach to replace both autografts and allografts to repair and remodel damaged bone tissue. Biocompatible porous titanium scaffold was manufactured through a powder metallurgy approach. Magnesium powder was used as space holder material which was compacted with titanium powder and removed during sintering. Evaluation of the porosity and mechanical properties showed a high level of compatibility with human cortical bone. Interconnectivity between pores is higher than 95% for porosity as low as 30%. The elastic moduli are 44.2GPa, 24.7GPa and 15.4GPa for 30%, 40% and 50% porosity samples which match well to that of natural bone (4-30GPa). The yield strengths for 30% and 40% porosity samples of 221.7MPa and 117MPa are superior to that of human cortical bone (130-180MPa). In-vitro cell culture tests on the scaffold samples using Human Mesenchymal Stem Cells (hMSCs) demonstrated their biocompatibility and indicated osseointegration potential. The scaffolds allowed cells to adhere and spread both on the surface and inside the pore structures. With increasing levels of porosity/interconnectivity, improved cell proliferation is obtained within the pores. It is concluded that samples with 30% porosity exhibit the best biocompatibility. The results suggest that porous titanium scaffolds generated using this manufacturing route have excellent potential for hard tissue engineering applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Understanding dental CAD/CAM for restorations--accuracy from a mechanical engineering viewpoint.

    Science.gov (United States)

    Tapie, Laurent; Lebon, Nicolas; Mawussi, Bernardin; Fron-Chabouis, Hélène; Duret, Francois; Attal, Jean-Pierre

    2015-01-01

    As is the case in the field of medicine, as well as in most areas of daily life, digital technology is increasingly being introduced into dental practice. Computer-aided design/ computer-aided manufacturing (CAD/CAM) solutions are available not only for chairside practice but also for creating inlays, crowns, fixed partial dentures (FPDs), implant abutments, and other dental prostheses. CAD/CAM dental practice can be considered as the handling of devices and software processing for the almost automatic design and creation of dental restorations. However, dentists who want to use dental CAD/CAM systems often do not have enough information to understand the variations offered by such technology practice. Knowledge of the random and systematic errors in accuracy with CAD/CAM systems can help to achieve successful restorations with this technology, and help with the purchasing of a CAD/CAM system that meets the clinical needs of restoration. This article provides a mechanical engineering viewpoint of the accuracy of CAD/ CAM systems, to help dentists understand the impact of this technology on restoration accuracy.

  17. Intracellular uptake: a possible mechanism for silver engineered nanoparticle toxicity to a freshwater alga Ochromonas danica.

    Directory of Open Access Journals (Sweden)

    Ai-Jun Miao

    2010-12-01

    Full Text Available The behavior and toxicity of silver engineered nanoparticles (Ag-ENs to the mixotrophic freshwater alga Ochromonas danica were examined in the present study to determine whether any other mechanisms are involved in their algal toxicity besides Ag(+ liberation outside the cells. Despite their good dispersability, the Ag-ENs were found to continuously aggregate and dissolve rapidly. When the initial nanoparticle concentration was lower than 10 µM, the total dissolved Ag(+ concentration ([Ag(+](T in the suspending media reached its maximum after 1 d and then decreased suggesting that Ag(+ release might be limited by the nanoparticle surface area under these conditions. Furthermore, Ag-EN dissolution extent remarkably increased in the presence of glutathione. In the Ag-EN toxicity experiment, glutathione was also used to eliminate the indirect effects of Ag(+ that was released. However, remarkable toxicity was still observed although the free Ag(+ concentration in the media was orders of magnitude lower than the non-observed effect concentration of Ag(+ itself. Such inhibitive effects were mitigated when more glutathione was added, but could never be completely eliminated. Most importantly, we demonstrate, for the first time, that Ag-ENs can be taken in and accumulated inside the algal cells, where they exerted their toxic effects. Therefore, nanoparticle internalization may be an alternative pathway through which algal growth can be influenced.

  18. Escapement mechanisms and the conversion of disequilibria; the engines of creation

    International Nuclear Information System (INIS)

    Branscomb, E.; Biancalani, T.; Goldenfeld, N.; Russell, M.

    2017-01-01

    Virtually every interesting natural phenomenon, not least life itself, entails physical systems being forced to flow thermodynamically up-hill, away from equilibrium rather than towards it. This requires the action of a mechanism, acting as an “engine”, which lashes the up-hill process to a more powerful one proceeding in its spontaneous, down-hill direction; in this way converting one disequilibrium into another. All organized and dynamic elements of creation, from the galactic to the atomic, can be viewed as powered by, or being the result of, engines of disequilibria conversion; each a link in a great hierarchical cascade of conversions. There is, however, widespread misunderstanding about how disequilibria conversions happen–and indeed about what physically causes them to happen–especially regarding the role of energy and of the physical meaning of free energy. We attempt here to describe and justify what we assert is the correct alternative view of how phenomena are powered in nature, focusing especially on the molecular-level conversion processes (often called “energy conserving”) that power life and that must, then acting in an entirely abiotic context, have driven it first into being.

  19. Explanation of the law on radiation injury prevention for mechanical engineers

    International Nuclear Information System (INIS)

    Fukuyama, Hiroyuki

    1991-01-01

    Generally to the facilities in which radioisotopes are treated, the Law on Radiation Injury Prevention is applied, but this law was revised in May, 1988, and enforced on April 1, 1989. As to the retroaction to existing facilities, the delay till March 31, 1991 is granted. In this report, by rearranging the system of contents so as to suit to mechanical engineers, the procedure of application and the standard for exhaust facilities and drainage facilities, which seem to be necessary matters, are described. In addition, the standard for facilities related to architecture which seems useful for design and construction if it is known as the basic matter and the standard for the control of the exposure of human bodies, surface contamination and measurement, related to the RI contamination in the air are referred to. The main points of revision in terms, unit and the law are shown. The Law on Radiation Injury Prevention is composed of the Law on Prevention of Radiation Injuries Due to Radioisotopes and Others, the enforcement ordinance, the enforcement regulation and the notice on determining the quantity of isotopes emitting radiation. (K.I.)

  20. Supplementation of exogenous adenosine 5'-triphosphate enhances mechanical properties of 3D cell-agarose constructs for cartilage tissue engineering.

    Science.gov (United States)

    Gadjanski, Ivana; Yodmuang, Supansa; Spiller, Kara; Bhumiratana, Sarindr; Vunjak-Novakovic, Gordana

    2013-10-01

    Formation of tissue-engineered cartilage is greatly enhanced by mechanical stimulation. However, direct mechanical stimulation is not always a suitable method, and the utilization of mechanisms underlying mechanotransduction might allow for a highly effective and less aggressive alternate means of stimulation. In particular, the purinergic, adenosine 5'-triphosphate (ATP)-mediated signaling pathway is strongly implicated in mechanotransduction within the articular cartilage. We investigated the effects of transient and continuous exogenous ATP supplementation on mechanical properties of cartilaginous constructs engineered using bovine chondrocytes and human mesenchymal stem cells (hMSCs) encapsulated in an agarose hydrogel. For both cell types, we have observed significant increases in equilibrium and dynamic compressive moduli after transient ATP treatment applied in the fourth week of cultivation. Continuous ATP treatment over 4 weeks of culture only slightly improved the mechanical properties of the constructs, without major changes in the total glycosaminoglycan (GAG) and collagen content. Structure-function analyses showed that transiently ATP-treated constructs, and in particular those based on hMSCs, had the highest level of correlation between compositional and mechanical properties. Transiently treated groups showed intense staining of the territorial matrix for GAGs and collagen type II. These results indicate that transient ATP treatment can improve functional mechanical properties of cartilaginous constructs based on chondrogenic cells and agarose hydrogels, possibly by improving the structural organization of the bulk phase and territorial extracellular matrix (ECM), that is, by increasing correlation slopes between the content of the ECM components (GAG, collagen) and mechanical properties of the construct.