The Stirling engine as a low cost tool to educate mechanical engineers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gros, J.; Munoz, M.; Moreno, F.

1995-12-31

The University of Zaragoza through CIRCE, the New Enterprise foundation, an Opel foundation and the local Government of Aragon have been developed a program to introduce the Stirling Engine as a low cost tool to educate students in mechanical engineering. The promotion of a prize like GNAT Power organized by the magazine Model Engineer in London, has improved the practical education of students in the field of mechanical devices and thermal engines. Two editions of the contest, 1993 and 1994, awarded the greatest power Stirling engine made by only using a little candle of paraffin as a heat source. Fourmore » engines were presented in the first edition, with an average power of about 100 mW, and seven engines in the second one, achieving a power of about 230 mW. Presentations in Technical Schools and the University have been carried out. Also low cost tools have been made for measuring an electronic device to draw the real internal pressure volume diagram using a PC. A very didactic software to design classic kinematic alpha, beta and gamma engines plus Ringbom beta and gamma engines has been created. A book is going to be published (in Spanish) explaining the design of small Stirling engines as a way to start with low cost research in thermal engines, a very difficult target with IC engines.« less

Fracture mechanics /Dryden Lecture/. [aerospace structural design applications

NASA Technical Reports Server (NTRS)

Hardrath, H. F.

1974-01-01

A historical outline of the engineering discipline of fracture mechanics is presented, and current analytical procedures are summarized. The current status of the discipline is assessed, and engineering applications are discussed, along with recommended directions for future study.

Performance deterioration of commercial high-bypass ratio turbofan engines

NASA Technical Reports Server (NTRS)

Mehalic, C. M.; Ziemianski, J. A.

1980-01-01

The results of engine performance deterioration investigations based on historical data, special engine tests, and specific tests to define the influence of flight loads and component clearances on performance are presented. The results of analyses of several damage mechanisms that contribute to performance deterioration such as blade tip rubs, airfoil surface roughness and erosion, and thermal distortion are also included. The significance of these damage mechanisms on component and overall engine performance is discussed.

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

NASA Astrophysics Data System (ADS)

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.

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

DOT National Transportation Integrated Search

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...

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

DOT National Transportation Integrated Search

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...

Safety engineering: KTA code of practice. Lifting mechanisms in nuclear plant

NASA Astrophysics Data System (ADS)

Lifting mechanisms safety requirements are discussed in accordance with the present state of development of science and engineering for the protection of life, health, and assets against the dangers of nuclear energy and the ill effects of ionizing radiation.

Quiet Clean Short-haul Experimental Engine (QCSEE). Under-The-Wing (UTW) engine boilerplate nacelle test report. Volume 3: Mechanical performance

NASA Technical Reports Server (NTRS)

1977-01-01

Results of initial tests of the under the wing experimental engine and boilerplate nacelle are presented. The mechanical performance of the engine is reported with emphasis on the advanced technology components. Technology elements of the propulsion system covered include: system dynamics, composite fan blades, reduction gear, lube and accessory drive system, fan frame, inlet, core cowl cooling, fan exhaust nozzle, and digital control system.

High-power baseline and motoring test results for the GPU-3 Stirling engine

NASA Technical Reports Server (NTRS)

Thieme, L. G.

1981-01-01

Test results are given for the full power range of the engine with both helium and hydrogen working fluids. Comparisons are made to previous testing using an alternator and resistance load bank to absorb the engine output. Indicated power results are presented as determined by several methods. Motoring tests were run to aid in determining engine mechanical losses. Comparisons are made between the results of motoring and energy-balance methods for finding mechanical losses.

MEMSlab: A Practical MEMS Course for the Fabrication, Packaging, and Testing of a Single-Axis Accelerometer

ERIC Educational Resources Information Center

Grundbacher, R.; Hoetzel, J. E.; Hierold, C.

2009-01-01

A microelectro-mechanical systems (MEMS) laboratory course (MEMSlab) in the Mechanical and Process Engineering Department at the Swiss Federal Institute of Technology (ETH Zurich), is presented. The course has been taught for four years and has been attended primarily by Master's students from mechanical and electrical engineering; since fall…

Incorporating a Product Archaeology Paradigm across the Mechanical Engineering Curriculum

ERIC Educational Resources Information Center

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…

Annual Conference Abstracts

ERIC Educational Resources Information Center

Engineering Education, 1976

1976-01-01

Presents the abstracts of 158 papers presented at the American Society for Engineering Education's annual conference at Knoxville, Tennessee, June 14-17, 1976. Included are engineering topics covering education, aerospace, agriculture, biomedicine, chemistry, computers, electricity, acoustics, environment, mechanics, and women. (SL)

RFID-Based Multidisciplinary Educational Platform to Improve the Engineering and Technology Curriculums

ERIC Educational Resources Information Center

Yelamarthi, Kumar

2012-01-01

Multidisciplinary projects involving electrical engineering (EE), mechanical engineering (ME), and computer engineering (CE) students are both exciting and difficult to conceptualize. Answering this challenge, this paper presents a multidisciplinary educational platform on radio frequency identification-based assistive devices. The combination of…

Marine Engine Mechanics. Performance Objectives. Intermediate Course.

ERIC Educational Resources Information Center

Jones, Marion

Several intermediate performance objectives and corresponding criterion measures are presented for each of ten terminal objectives for a two-semester course (3 hours daily). This 540-hour intermediate course includes advanced troubleshooting techniques on outboard marine engines, inboard-outboard marine engines, inboard marine engines, boat…

Engineering Lubrication in Articular Cartilage

PubMed Central

McNary, Sean M.; Athanasiou, Kyriacos A.

2012-01-01

Despite continuous progress toward tissue engineering of functional articular cartilage, significant challenges still remain. Advances in morphogens, stem cells, and scaffolds have resulted in enhancement of the bulk mechanical properties of engineered constructs, but little attention has been paid to the surface mechanical properties. In the near future, engineered tissues will be able to withstand and support the physiological compressive and tensile forces in weight-bearing synovial joints such as the knee. However, there is an increasing realization that these tissue-engineered cartilage constructs will fail without the optimal frictional and wear properties present in native articular cartilage. These characteristics are critical to smooth, pain-free joint articulation and a long-lasting, durable cartilage surface. To achieve optimal tribological properties, engineered cartilage therapies will need to incorporate approaches and methods for functional lubrication. Steady progress in cartilage lubrication in native tissues has pushed the pendulum and warranted a shift in the articular cartilage tissue-engineering paradigm. Engineered tissues should be designed and developed to possess both tribological and mechanical properties mirroring natural cartilage. In this article, an overview of the biology and engineering of articular cartilage structure and cartilage lubrication will be presented. Salient progress in lubrication treatments such as tribosupplementation, pharmacological, and cell-based therapies will be covered. Finally, frictional assays such as the pin-on-disk tribometer will be addressed. Knowledge related to the elements of cartilage lubrication has progressed and, thus, an opportune moment is provided to leverage these advances at a critical step in the development of mechanically and tribologically robust, biomimetic tissue-engineered cartilage. This article is intended to serve as the first stepping stone toward future studies in functional tissue engineering of articular cartilage that begins to explore and incorporate methods of lubrication. PMID:21955119

Elements of Motivational Structure for Studying Mechanical Engineering

ERIC Educational Resources Information Center

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…

Gasoline Engine Mechanics. Performance Objectives. Intermediate Course.

ERIC Educational Resources Information Center

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…

Application of superalloy powder metallurgy for aircraft engines

NASA Technical Reports Server (NTRS)

Dreshfield, R. L.; Miner, R. V., Jr.

1980-01-01

The results of the Materials for Advanced Turbine Engines (MATE) program initiated by NASA are presented. Mechanical properties comparisons are made for superalloy parts produced by as-HIP powder consolidation and by forging of HIP consolidated billets. The effect of various defects on the mechanical properties of powder parts are shown.

Activities of the Institute for Mechanical Engineering

NASA Astrophysics Data System (ADS)

The Institute of Mechanical Engineering (IME) is part of Canada's National Research Council. Its mission is to undertake, support, promote, and disseminate research and development in the mechanical engineering aspects of three vital sectors of the Canadian economy: transportation, resource industries, and manufacturing. The IME achieves its mission by performing research and development in its own facilities; by developing, providing, and transferring expertise and knowledge; by making its research facilities available to collaborators and clients; and by participating in international liaison and collaborative research activities. Six research programs are conducted in the IME: Advanced Manufacturing Technology; Coastal Zone Engineering; Cold Regions Engineering; Combustion and Fluids Engineering; Ground Transportation Technology; and Machinery and Engine Technology. The rationale and major research thrusts of each program are described, and specific achievements in 1991-92 are reviewed. Lists of technical reports and papers presented by IME personnel are also included.

The Evaluation of the Effectiveness of ESP Courses in Enhancing Technical Translation Proficiency: A Case Study of ESP Course for Mechanical Engineering Students

ERIC Educational Resources Information Center

Hatam, Amir Hussein; Shafiei, Shilan

2012-01-01

The purpose of the present study was twofold. Firstly, it tried to investigate the relationship between the technical English proficiency of the students of Mechanical Engineering in the universities of Iran and their technical translation proficiency in translating technical texts of Mechanics. Secondly, it attempted to evaluate the effectiveness…

Example of Good Practice of a Learning Environment with a Classroom Response System in a Mechanical Engineering Bachelor Course

ERIC Educational Resources Information Center

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…

Graduate engineering research participation in aeronautics

NASA Technical Reports Server (NTRS)

Roberts, A. S., Jr.

1986-01-01

The Aeronautics Graduate Research Program commenced in 1971, with the primary goal of engaging students who qualified for regular admission to the Graduate School of Engineering at Old Dominion University in a graduate engineering research and study program in collaboration with NASA Langley Research Center, Hampton, Virginia. The format and purposes of this program are discussed. Student selection and program statistics are summarized. Abstracts are presented in the folowing areas: aircraft design, aerodynamics, lift/drag characteristics; avionics; fluid mechanics; solid mechanics; instrumentation and measurement techniques; thermophysical properties experiments; large space structures; earth orbital dynamics; and environmental engineering.

Gasoline Engine Mechanics. Performance Objectives. Basic Course.

ERIC Educational Resources Information Center

Jones, Marion

Several intermediate performance objectives and corresponding criterion measures are listed for each of five terminal objectives presented in this curriculum guide for a basic gasoline engine mechanics course at the secondary level. (For the intermediate course guide see CE 010 946.) The materials were developed for a two semester (2 hours daily)…

Mechanical Engineering at KSC: 'How I spend My Hours from 9 to 5 and Draw a Paycheck'

NASA Technical Reports Server (NTRS)

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.

Alternative evaluation of innovations’ effectiveness in mechanical engineering

NASA Astrophysics Data System (ADS)

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”.

Newton's Laws, Euler's Laws and the Speed of Light

ERIC Educational Resources Information Center

Whitaker, Stephen

2009-01-01

Chemical engineering students begin their studies of mechanics in a department of physics where they are introduced to the mechanics of Newton. The approach presented by physicists differs in both perspective and substance from that encountered in chemical engineering courses where Euler's laws provide the foundation for studies of fluid and solid…

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

NASA Astrophysics Data System (ADS)

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 disseminate research in all fields of mechanical engineering. Topics cover synthesis, applications, and fundamental studies of the topics related to mechanical engineering. In addition, booths for industries to showcase their state-of-the-art products are also provided. The organizing committee of the conference thanks all the participants for their fruitful work and personal contribution to the development of these conference proceedings.

The Use of Mini-projects in the Teaching of Geotechnics to Civil Engineering Undergraduates.

ERIC Educational Resources Information Center

Anderson, W. F.; And Others

1985-01-01

Geotechnics (which encompasses soil and rock mechanics, engineering geology, foundation design, and ground engineering methods) is a major component of virtually all civil engineering courses. Show how mini-projects are used to teach this subject. Format of projects, development of presentation skills, and assessment considerations are discussed.…

Engineering Students Learning Preferences in UNITEN: Comparative Study and Patterns of Learning Styles

ERIC Educational Resources Information Center

Lee, Chen Kang; Sidhu, Manjit Singh

2015-01-01

Engineering educators have been increasingly taking the learning style theories into serious consideration as part of their efforts to enhance the teaching and learning in engineering. This paper presents a research study to investigate the learning style preference of the mechanical engineering students in Universiti Tenaga Nasional (UNITEN),…

Computers in Engineering Teaching.

ERIC Educational Resources Information Center

Rushby, N. J.

This bibliography cites 26 books, papers, and reports dealing with various uses of computers in engineering education; and describes several computer programs available for use in teaching aeronautical, chemical, civil, electrical and electronic, mechanical, and nuclear engineering. Each computer program entry is presented by name, author,…

Engine balance apparatus and accessory drive device

NASA Technical Reports Server (NTRS)

Brogdon, James William (Inventor); Gill, David Keith (Inventor)

2000-01-01

A balancing mechanism for an engine that has a rotating crankshaft and reciprocating pistons such as those engines used in automobiles, aircrafts, boats, piston-driven compressors, piston-driven slider crank mechanisms, etc. The present balancing mechanism may comprise a first balance mass non-rotatably affixed to the crankshaft and a second balance mass rotatably supported on the crankshaft. A driver assembly is affixed to crankshaft to cause the second balance mass to rotate in a direction that is opposite to the direction in which the crank shaft is rotating. The driver assembly may include auxiliary gears configured to transport rotary power to auxiliary components.

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

NASA Astrophysics Data System (ADS)

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.

Efficiency Assessment of a Blended-Learning Educational Methodology in Engineering

NASA Astrophysics Data System (ADS)

Rogado, Ana Belén González; Conde, Ma José Rodríguez; Migueláñez, Susana Olmos; Riaza, Blanca García; Peñalvo, Francisco José García

The content of this presentation highlights the importance of an active learning methodology in engineering university degrees in Spain. We present of some of the outcomes from an experimental study carried out during the academic years 2007/08 and 2008/09 with engineering students (Technical Industrial Engineering: Mechanics, Civical Design Engineering: Civical building, Technical Architecture and Technical Engineering on Computer Management.) at the University of Salamanca. In this research we select a subject which is common for the four degrees: Computer Science. This study has the aim of contributing to the improvement of education and teaching methods for a better performance of students in Engineering.

The International Congress of Mechanical Engineering and Agricultural Sciences - CIIMCA 2013

NASA Astrophysics Data System (ADS)

Remolina-Millán, Aduljay; Hernández-Arroyo, Emil

2014-06-01

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 Conference photograph Conference photograph 'Universidad Pontificia Bolivariana seccional Bucaramanga' host of the first International Mechanical Engineering and Agricultural Sciences Congress - CIIMCA 2013 - Floridablanaca, Colombia. Conference photograph Closure of CIIMCA 2013. Details of the editorial committee and acknowledgements are available in the PDF.

Compact scheme for systems of equations applied to fundamental problems of mechanics of continua

NASA Technical Reports Server (NTRS)

Klimkowski, Jerzy Z.

1990-01-01

Compact scheme formulation was used in the treatment of boundary conditions for a system of coupled diffusion and Poisson equations. Models and practical solutions of specific engineering problems arising in solid mechanics, chemical engineering, heat transfer and fuid mechanics are described and analyzed for efficiency and accuracy. Only 2-D cases are discussed and a new method of numerical treatment of boundary conditions common in the fundamental problems of mechanics of continua is presented.

Advances in engineering science, volume 1

NASA Technical Reports Server (NTRS)

1976-01-01

Proceedings from a conference on engineering advances are presented, including materials science, fracture mechanics, and impact and vibration testing. The tensile strength and moisture transport of laminates are also discussed.

Lubricant Formulations to Enhance Engine Efficiency in Modern Internal Combustion Engines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Wai; Wong, Victor; Plumley, Michael

2017-04-19

The research program presented aimed to investigate, develop, and demonstrate low-friction, environmentally-friendly and commercially-feasible lubricant formulations that would significantly improve the mechanical efficiency of modern engines without incurring increased wear, emissions or deterioration of the emission-aftertreatment system.

Mechanical Autonomous Stochastic Heat Engine

NASA Astrophysics Data System (ADS)

Serra-Garcia, Marc; Foehr, André; Molerón, Miguel; Lydon, Joseph; Chong, Christopher; Daraio, Chiara

2016-07-01

Stochastic heat engines are devices that generate work from random thermal motion using a small number of highly fluctuating degrees of freedom. Proposals for such devices have existed for more than a century and include the Maxwell demon and the Feynman ratchet. Only recently have they been demonstrated experimentally, using, e.g., thermal cycles implemented in optical traps. However, recent experimental demonstrations of classical stochastic heat engines are nonautonomous, since they require an external control system that prescribes a heating and cooling cycle and consume more energy than they produce. We present a heat engine consisting of three coupled mechanical resonators (two ribbons and a cantilever) subject to a stochastic drive. The engine uses geometric nonlinearities in the resonating ribbons to autonomously convert a random excitation into a low-entropy, nonpassive oscillation of the cantilever. The engine presents the anomalous heat transport property of negative thermal conductivity, consisting in the ability to passively transfer energy from a cold reservoir to a hot reservoir.

Mechanical Autonomous Stochastic Heat Engine.

PubMed

Serra-Garcia, Marc; Foehr, André; Molerón, Miguel; Lydon, Joseph; Chong, Christopher; Daraio, Chiara

2016-07-01

Stochastic heat engines are devices that generate work from random thermal motion using a small number of highly fluctuating degrees of freedom. Proposals for such devices have existed for more than a century and include the Maxwell demon and the Feynman ratchet. Only recently have they been demonstrated experimentally, using, e.g., thermal cycles implemented in optical traps. However, recent experimental demonstrations of classical stochastic heat engines are nonautonomous, since they require an external control system that prescribes a heating and cooling cycle and consume more energy than they produce. We present a heat engine consisting of three coupled mechanical resonators (two ribbons and a cantilever) subject to a stochastic drive. The engine uses geometric nonlinearities in the resonating ribbons to autonomously convert a random excitation into a low-entropy, nonpassive oscillation of the cantilever. The engine presents the anomalous heat transport property of negative thermal conductivity, consisting in the ability to passively transfer energy from a cold reservoir to a hot reservoir.

Type Safe Extensible Programming

NASA Astrophysics Data System (ADS)

Chae, Wonseok

2009-10-01

Software products evolve over time. Sometimes they evolve by adding new features, and sometimes by either fixing bugs or replacing outdated implementations with new ones. When software engineers fail to anticipate such evolution during development, they will eventually be forced to re-architect or re-build from scratch. Therefore, it has been common practice to prepare for changes so that software products are extensible over their lifetimes. However, making software extensible is challenging because it is difficult to anticipate successive changes and to provide adequate abstraction mechanisms over potential changes. Such extensibility mechanisms, furthermore, should not compromise any existing functionality during extension. Software engineers would benefit from a tool that provides a way to add extensions in a reliable way. It is natural to expect programming languages to serve this role. Extensible programming is one effort to address these issues. In this thesis, we present type safe extensible programming using the MLPolyR language. MLPolyR is an ML-like functional language whose type system provides type-safe extensibility mechanisms at several levels. After presenting the language, we will show how these extensibility mechanisms can be put to good use in the context of product line engineering. Product line engineering is an emerging software engineering paradigm that aims to manage variations, which originate from successive changes in software.

Cam Design Projects in an Advanced CAD Course for Mechanical Engineers

ERIC Educational Resources Information Center

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…

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

ERIC Educational Resources Information Center

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…

Mississippi Curriculum Framework for Diesel Equipment Repair & Service (Program CIP: 47.0605--Diesel Engine Mechanic & Repairer). Secondary Programs.

ERIC Educational Resources Information Center

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…

Fluid Mechanics

NASA Astrophysics Data System (ADS)

Pnueli, David; Gutfinger, Chaim

1997-01-01

This text is intended for the study of fluid mechanics at an intermediate level. The presentation starts with basic concepts, in order to form a sound conceptual structure that can support engineering applications and encourage further learning. The presentation is exact, incorporating both the mathematics involved and the physics needed to understand the various phenomena in fluid mechanics. Where a didactical choice must be made between the two, the physics prevails. Throughout the book the authors have tried to reach a balance between exact presentation, intuitive grasp of new ideas, and creative applications of concepts. This approach is reflected in the examples presented in the text and in the exercises given at the end of each chapter. Subjects treated are hydrostatics, viscous flow, similitude and order of magnitude, creeping flow, potential flow, boundary layer flow, turbulent flow, compressible flow, and non-Newtonian flows. This book is ideal for advanced undergraduate students in mechanical, chemical, aerospace, and civil engineering. Solutions manual available.

Project CAD as of July 1978: CAD support project, situation in July 1978

NASA Technical Reports Server (NTRS)

Boesch, L.; Lang-Lendorff, G.; Rothenberg, R.; Stelzer, V.

1979-01-01

The structure of Computer Aided Design (CAD) and the requirements for program developments in past and future are described. The actual standard and the future aims of CAD programs are presented. The developed programs in: (1) civil engineering; (2) mechanical engineering; (3) chemical engineering/shipbuilding; (4) electrical engineering; and (5) general programs are discussed.

A reduced mechanism for biodiesel surrogates with low temperature chemistry for compression ignition engine applications

NASA Astrophysics Data System (ADS)

Luo, Zhaoyu; Plomer, Max; Lu, Tianfeng; Som, Sibendu; Longman, Douglas E.

2012-04-01

Biodiesel is a promising alternative fuel for compression ignition (CI) engines. It is a renewable energy source that can be used in these engines without significant alteration in design. The detailed chemical kinetics of biodiesel is however highly complex. In the present study, a skeletal mechanism with 123 species and 394 reactions for a tri-component biodiesel surrogate, which consists of methyl decanoate, methyl 9-decanoate and n-heptane was developed for simulations of 3-D turbulent spray combustion under engine-like conditions. The reduction was based on an improved directed relation graph (DRG) method that is particularly suitable for mechanisms with many isomers, followed by isomer lumping and DRG-aided sensitivity analysis (DRGASA). The reduction was performed for pressures from 1 to 100 atm and equivalence ratios from 0.5 to 2 for both extinction and ignition applications. The initial temperatures for ignition were from 700 to 1800 K. The wide parameter range ensures the applicability of the skeletal mechanism under engine-like conditions. As such the skeletal mechanism is applicable for ignition at both low and high temperatures. Compared with the detailed mechanism that consists of 3299 species and 10806 reactions, the skeletal mechanism features a significant reduction in size while still retaining good accuracy and comprehensiveness. The validations of ignition delay time, flame lift-off length and important species profiles were also performed in 3-D engine simulations and compared with the experimental data from Sandia National Laboratories under CI engine conditions.

VR/LE engine with a variable R/L during a single cycle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rychter, T.J.; Teodorczyk, A.

1985-01-01

A new concept of an engine, called a Variable R/L Engine (VR/LE) is presented. The main feature of the engine is the continuous change of the crank-radius to connecting-rod-length ratio (R/L) during the single engine cycle. The variations of the phase angle result in changes of all the engine stroke lengths and also-they are causing the changes of the thermodynamic cycle of the engine. Therefore the phase angle variations make it possible to regulate continuously the compression ratio and the displacement volume of the engine within the range which depends on the engine mechanism geometry. The presented concept can bemore » applied to all the types of the IC piston engines, independently of their size and operation principle.« less

EDITORIAL: Precision Measurement Technology at the 56th International Scientific Colloquium in Ilmenau Precision Measurement Technology at the 56th International Scientific Colloquium in Ilmenau

NASA Astrophysics Data System (ADS)

Manske, E.; Froehlich, T.

2012-07-01

The 56th International Scientific Colloquium was held from 12th to 16th September 2011 at the Ilmenau University of Technology in Germany. This event was organized by the Faculty of Mechanical Engineering under the title: 'Innovation in Mechanical Engineering—Shaping the Future' and was intended to reflect the entire scope of modern mechanical engineering. In three main topics many research areas, all involving innovative mechanical engineering, were addressed, especially in the fields of Precision Engineering and Precision Measurement Technology, Mechatronics and Ambient-Assisted Living and Systems Technology. The participants were scientists from 21 countries, and 166 presentations were given. This special issue of Measurement Science and Technology presents selected contributions on 'Precision Engineering and Precision Measurement Technology'. Over three days the conference participants discussed novel scientific results in two sessions. The main topics of these sessions were: Measurement and Sensor Technology Process measurement Laser measurement Force measurement Weighing technology Temperature measurement Measurement dynamics and Nanopositioning and Nanomeasuring Technology Nanopositioning and nanomeasuring machines Nanometrology Probes and tools Mechanical design Signal processing Control and visualization in NPM devices Significant research results from the Collaborative Research Centre SFB 622 'Nanopositioning and Nanomeasuring Machines' funded by the German Research Foundation (DFG) were presented as part of this topic. As the Chairmen, our special thanks are due to the International Programme Committee, the Organization Committee and the conference speakers as well as colleagues from the Institute of Process Measurement and Sensor Technology who helped make the conference a success. We would like to thank all the authors for their contributions, the referees for their time spent reviewing the contributions and their valuable comments, and the whole Editorial Board of Measurement Science and Technology for their support.

Engineering Change Management Method Framework in Mechanical Engineering

NASA Astrophysics Data System (ADS)

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.

A vibroacoustic diagnostic system as an element improving road transport safety.

PubMed

Komorska, Iwona

2013-01-01

Mechanical defects of a vehicle driving system can be dangerous on the road. Diagnostic systems, which monitor operations of electric and electronic elements and devices of vehicles, are continuously developed and improved, while defects of mechanical systems are still not managed properly. This article proposes supplementing existing on-board diagnostics with a system of diagnosing selected defects to minimize their impact. It presents a method of diagnosing mechanical defects of the engine, gearbox and other elements of the driving system on the basis of a model of the vibration signal obtained adaptively. This method is suitable for engine valves, engine head gasket, main gearbox, joints, etc.

Robert Henry Thurston: Professionalism and Engineering Education

ERIC Educational Resources Information Center

Nienkamp, Paul

2016-01-01

Robert Henry Thurston is presented in this article. He provides one the most significant examples of professionalizing engineering through innovative education and promoting scientific education practices in the late nineteenth century. The son of a draftsmen and steam engine mechanic, Thurston spent his early years in Providence, Rhode Island.…

Quiet Clean Short-haul Experimental Engine (QCSEE). The aerodynamic and mechanical design of the QCSEE over-the-wing fan

NASA Technical Reports Server (NTRS)

1976-01-01

The aerodynamic and mechanical design of a fixed-pitch 1.36 pressure ratio fan for the over-the-wing (OTW) engine is presented. The fan has 28 blades. Aerodynamically, the fan blades were designed for a composite blade, but titanium blades were used in the experimental fan as a cost savings measure.

The making of the mechanical universe

NASA Technical Reports Server (NTRS)

Blinn, James

1989-01-01

The Mechanical Universe project required the production of over 550 different animated scenes, totaling about 7 and 1/2 hours of screen time. The project required the use of a wide range of techniques and motivated the development of several different software packages. A documentation is presented of many aspects of the project, encompassing artistic design issues, scientific simulations, software engineering, and video engineering.

Mechanical-Kinetic Modeling of a Molecular Walker from a Modular Design Principle

NASA Astrophysics Data System (ADS)

Hou, Ruizheng; Loh, Iong Ying; Li, Hongrong; Wang, Zhisong

2017-02-01

Artificial molecular walkers beyond burnt-bridge designs are complex nanomachines that potentially replicate biological walkers in mechanisms and functionalities. Improving the man-made walkers up to performance for widespread applications remains difficult, largely because their biomimetic design principles involve entangled kinetic and mechanical effects to complicate the link between a walker's construction and ultimate performance. Here, a synergic mechanical-kinetic model is developed for a recently reported DNA bipedal walker, which is based on a modular design principle, potentially enabling many directional walkers driven by a length-switching engine. The model reproduces the experimental data of the walker, and identifies its performance-limiting factors. The model also captures features common to the underlying design principle, including counterintuitive performance-construction relations that are explained by detailed balance, entropy production, and bias cancellation. While indicating a low directional fidelity for the present walker, the model suggests the possibility of improving the fidelity above 90% by a more powerful engine, which may be an improved version of the present engine or an entirely new engine motif, thanks to the flexible design principle. The model is readily adaptable to aid these experimental developments towards high-performance molecular walkers.

Microfabrication of hierarchical structures for engineered mechanical materials

NASA Astrophysics Data System (ADS)

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.

Design study of RL10 derivatives. Volume 3, part 1: Preliminary interface control document. [development of baseline engines for space tug vehicles

NASA Technical Reports Server (NTRS)

Adams, A.

1973-01-01

The Interface Control Document contains engine information necessary for installation of the baseline RL10 Derivative engines in the Space Tug vehicle. The ICD presents a description of the baseline engines and their operating characteristics, mass and load characteristics, and environmental criteria. The document defines the engine/vehicle mechanical, electrical, fluid and pneumatic interface requirements.

The Further Development of Heat-Resistant Materials for Aircraft Engines

NASA Technical Reports Server (NTRS)

Bollenrath, Franz

1946-01-01

The present report deals with the problems involved in the greater utilization and development of aircraft engine materials, and specifically; piston materials, cylinder heads, exhaust valves, and exhaust gas turbine blading. The blades of the exhaust gas turbine are likely to be the highest stressed components of modern power plants from a thermal-mechanical and chemical standpoint, even though the requirements on exhaust valves of engines with gasoline injection are in general no less stringent. For the fire plate in Diesel engines the specifications for mechanical strength and design are not so stringent, and the question of heat resistance, which under these circumstances is easier obtainable, predominates.

Engineering study of the rotary-vee engine concept

NASA Technical Reports Server (NTRS)

Willis, Edward A.; Bartrand, Timothy A.; Beard, John E.

1989-01-01

The applicable thermodynamic cycle and performance considerations when the rotary-vee mechanism is used as an internal combustion (I.C.) heat engine are reviewed. Included is a simplified kinematic analysis and studies of the effects of design parameters on the critical pressures, torques and parasitic losses. A discussion of the principal findings is presented.

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

NASA Astrophysics Data System (ADS)

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.

Computer program for a four-cylinder-Stirling-engine controls simulation

NASA Technical Reports Server (NTRS)

Daniels, C. J.; Lorenzo, C. F.

1982-01-01

A four cylinder Stirling engine, transient engine simulation computer program is presented. The program is intended for controls analysis. The associated engine model was simplified to shorten computer calculation time. The model includes engine mechanical drive dynamics and vehicle load effects. The computer program also includes subroutines that allow: (1) acceleration of the engine by addition of hydrogen to the system, and (2) braking of the engine by short circuiting of the working spaces. Subroutines to calculate degraded engine performance (e.g., due to piston ring and piston rod leakage) are provided. Input data required to run the program are described and flow charts are provided. The program is modular to allow easy modification of individual routines. Examples of steady state and transient results are presented.

Proving the suitability of magnetoelectric stimuli for tissue engineering applications.

PubMed

Ribeiro, C; Correia, V; Martins, P; Gama, F M; Lanceros-Mendez, S

2016-04-01

A novel approach for tissue engineering applications based on the use of magnetoelectric materials is presented. This work proves that magnetoelectric Terfenol-D/poly(vinylidene fluoride-co-trifluoroethylene) composites are able to provide mechanical and electrical stimuli to MC3T3-E1 pre-osteoblast cells and that those stimuli can be remotely triggered by an applied magnetic field. Cell proliferation is enhanced up to ≈ 25% when cells are cultured under mechanical (up to 110 ppm) and electrical stimulation (up to 0.115 mV), showing that magnetoelectric cell stimulation is a novel and suitable approach for tissue engineering allowing magnetic, mechanical and electrical stimuli. Copyright © 2015 Elsevier B.V. All rights reserved.

Quiet Clean Short-haul Experimental Engine (QCSEE). Ball spline pitch change mechanism design report

NASA Technical Reports Server (NTRS)

1978-01-01

Detailed design parameters are presented for a variable-pitch change mechanism. The mechanism is a mechanical system containing a ball screw/spline driving two counteracting master bevel gears meshing pinion gears attached to each of 18 fan blades.

Currently available medical engineering degrees in the UK. Part 1: Undergraduate degrees.

PubMed

Joyce, T

2009-05-01

This paper reviews mechanical-engineering-based medical engineering degrees which are currently provided at undergraduate level in the UK. At present there are 14 undergraduate degree programmes in medical engineering, offered by the University of Bath, University of Birmingham, University of Bradford, Cardiff University, University of Hull, Imperial College London, University of Leeds, University of Nottingham, University of Oxford, Queen Mary University of London, University of Sheffield, University of Southampton, University of Surrey, and Swansea University. All these undergraduate courses are delivered on a full-time basis, both 3 year BEng and 4 year MEng degrees. Half of the 14 degree courses share a core first 2 years with a mechanical engineering stream. The other seven programmes include medical engineering modules earlier in their degrees. Within the courses, a very wide range of medical-engineering-related modules are offered, although more common modules include biomaterials, biomechanics, and anatomy and physiology.

Mechanical Design of Spacecraft

NASA Technical Reports Server (NTRS)

1962-01-01

In the spring of 1962, engineers from the Engineering Mechanics Division of the Jet Propulsion Laboratory gave a series of lectures on spacecraft design at the Engineering Design seminars conducted at the California Institute of Technology. Several of these lectures were subsequently given at Stanford University as part of the Space Technology seminar series sponsored by the Department of Aeronautics and Astronautics. Presented here are notes taken from these lectures. The lectures were conceived with the intent of providing the audience with a glimpse of the activities of a few mechanical engineers who are involved in designing, building, and testing spacecraft. Engineering courses generally consist of heavily idealized problems in order to allow the more efficient teaching of mathematical technique. Students, therefore, receive a somewhat limited exposure to actual engineering problems, which are typified by more unknowns than equations. For this reason it was considered valuable to demonstrate some of the problems faced by spacecraft designers, the processes used to arrive at solutions, and the interactions between the engineer and the remainder of the organization in which he is constrained to operate. These lecture notes are not so much a compilation of sophisticated techniques of analysis as they are a collection of examples of spacecraft hardware and associated problems. They will be of interest not so much to the experienced spacecraft designer as to those who wonder what part the mechanical engineer plays in an effort such as the exploration of space.

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

PubMed

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.

The convective engine paradigm for the supernova explosion mechanism and its consequences.

NASA Astrophysics Data System (ADS)

Herant, M.

1995-05-01

The convective engine paradigm for the explosion mechanism in core collapse supernovae is presented in a pedagogical manner. A candid evaluation of its strengths and weaknesses is attempted. The case where the convective mode corresponds to l=1, m=0 (one inflow, one outflow) is explored in more detail. The author also discusses the potential importance of such a convective pattern for neutron star kicks.

Civil and mechanical engineering applications of sensitivity analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Komkov, V.

1985-07-01

In this largely tutorial presentation, the historical development of optimization theories has been outlined as they applied to mechanical and civil engineering designs and the development of modern sensitivity techniques during the last 20 years has been traced. Some of the difficulties and the progress made in overcoming them have been outlined. Some of the recently developed theoretical methods have been stressed to indicate their importance to computer-aided design technology.

Assessment of the mechanical properties of sisal fiber-reinforced silty clay using triaxial shear tests.

PubMed

Wu, Yankai; Li, Yanbin; Niu, Bin

2014-01-01

Fiber reinforcement is widely used in construction engineering to improve the mechanical properties of soil because it increases the soil's strength and improves the soil's mechanical properties. However, the mechanical properties of fiber-reinforced soils remain controversial. The present study investigated the mechanical properties of silty clay reinforced with discrete, randomly distributed sisal fibers using triaxial shear tests. The sisal fibers were cut to different lengths, randomly mixed with silty clay in varying percentages, and compacted to the maximum dry density at the optimum moisture content. The results indicate that with a fiber length of 10 mm and content of 1.0%, sisal fiber-reinforced silty clay is 20% stronger than nonreinforced silty clay. The fiber-reinforced silty clay exhibited crack fracture and surface shear fracture failure modes, implying that sisal fiber is a good earth reinforcement material with potential applications in civil engineering, dam foundation, roadbed engineering, and ground treatment.

Engineering study on the rotary-vee engine concept

NASA Technical Reports Server (NTRS)

Willis, Edward A.; Bartland, Timothy A.; Beard, John E.

1989-01-01

This paper provides a review of the applicable thermodynamic cycle and performance considerations when the rotary-vee mechanism is used as an internal combustion (IC) heat engine. Included is a simplified kinematic analysis and studies of the effects of design parameters on the critical pressures, torques and parasitic losses. A discussion of the principal findings is presented.

Mississippi Curriculum Framework for Small Engine Repair (Program CIP: 47.0606--Small Engine Mechanic and Repairer). Secondary Programs.

ERIC Educational Resources Information Center

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 small engine repair I and II. Presented first are a program description…

Theoretical study of a thermo-acousto-electric generator equipped with an electroacoustic feedback loop

NASA Astrophysics Data System (ADS)

Olivier, Come; Penelet, Guillaume; Poignand, Gaelle; Lotton, Pierrick

2015-10-01

A simplified model of a Stirling-type thermoacoustic engine coupled to a resonant mechanical system is presented. The acoustic network is presented as its temperature-dependent lumped element equivalent, and the nonlinear effects involved in such engines are accounted for in a nonlinear heat equation governing the temperature distribution through the thermoacoustic core. The low-order model is sufficient to capture the behavior of the engine, both in terms of stability and dynamic behavior.

Development of Mechanics in Support of Rocket Technology in Ukraine

NASA Astrophysics Data System (ADS)

Prisnyakov, Vladimir

2003-06-01

The paper analyzes the advances of mechanics made in Ukraine in resolving various problems of space and rocket technology such as dynamics and strength of rockets and rocket engines, rockets of different purpose, electric rocket engines, and nonstationary processes in various systems of rockets accompanied by phase transitions of working media. Achievements in research on the effect of vibrations and gravitational fields on the behavior of space-rocket systems are also addressed. Results obtained in investigating the reliability and structural strength durability conditions for nuclear installations, solid- and liquid-propellant engines, and heat pipes are presented

Mechanics: Statics; A Syllabus.

ERIC Educational Resources Information Center

Compo, Louis

The instructor's guide presents material for structuring an engineering fundamentals course covering the basic laws of statistics as part of a mechanical technology program. Detailed behavioral objectives are described for the following five areas of course content: principles of mechanics, two-dimensional equilibrium, equilibrium of internal…

The formation of students’ engineering thinking as a way to create new techniques, technologies, materials

NASA Astrophysics Data System (ADS)

Gilmanshin, Iskander; Gilmanshina, Suriya

2016-06-01

Engineering thinking is regarded as the quality of the person, which is stimulating the human need for the creation of new techniques, technologies and materials. Applications in the study of competence approach allows us to consider a professional thinking as one of the core competencies required for successful engineer innovations in mechanical engineering. The author's definition of professional engineering thinking is presented. The ways of its formation at students of technical fields enrolled in university courses are illustrated

Aircraft gas-turbine engines: noise reduction and vibration control. January 1973-November 1988 (Citations from Information Services in Mechanical Engineering data base). Report for January 1973-November 1988

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1988-12-01

This bibliography contains citations concerning the design of aircraft gas-turbine engines with respect to noise reduction and vibration control. The aerodynamics of inlet design is presented for several types of engine applications including turbofan, turboprop, and vertical takeoff and landing aircraft. Helicopter engines are excluded from this bibliography. (This updated bibliography contains 212 citations, 28 of which are new entries to the previous edition.)

A classification of the mechanisms producing pathological tissue changes.

PubMed

Grippo, John O; Oh, Daniel S

2013-05-01

The objectives are to present a classification of mechanisms which can produce pathological changes in body tissues and fluids, as well as to clarify and define the term biocorrosion, which has had a singular use in engineering. Considering the emerging field of biomedical engineering, it is essential to use precise definitions in the lexicons of engineering, bioengineering and related sciences such as medicine, dentistry and veterinary medicine. The mechanisms of stress, friction and biocorrosion and their pathological effects on tissues are described. Biocorrosion refers to the chemical, biochemical and electrochemical changes by degradation or induced growth of living body tissues and fluids. Various agents which can affect living tissues causing biocorrosion are enumerated which support the necessity and justify the use of this encompassing and more precise definition of biocorrosion. A distinction is made between the mechanisms of corrosion and biocorrosion.

On Unsaturated Soil Mechanics - Personal Views on Current Research

NASA Astrophysics Data System (ADS)

Pande, G. N.; Pietruszczak, S.

2015-09-01

This paper presents the authors' personal views on current research being conducted by various research groups around the world in the broad area of mechanics of unsaturated geomaterials in general and soils in particular. The topic is of interest to a wide spectrum of scientists and engineers working in diverse areas such as geology and geophysics, powder technology, agricultural, petroleum, chemical, geotechnical, civil, environmental and nuclear engineering. Even if we restrict ourselves to civil, geotechnical and environmental engineering, it is noted that a plethora of hypotheses as well as a number of empirical and semi-empirical relations have been introduced for describing the mechanics of unsaturated porous media. However, many of these proposed advances as well as methods of testing may lack sound theoretical basis.

Loss terms in free-piston Stirling engine models

NASA Technical Reports Server (NTRS)

Gordon, Lloyd B.

1992-01-01

Various models for free piston Stirling engines are reviewed. Initial models were developed primarily for design purposes and to predict operating parameters, especially efficiency. More recently, however, such models have been used to predict engine stability. Free piston Stirling engines have no kinematic constraints and stability may not only be sensitive to the load, but also to various nonlinear loss and spring constraints. The present understanding is reviewed of various loss mechanisms for free piston Stirling engines and how they have been incorporated into engine models is discussed.

An Exploratory Study to Analyze New Skill Content in Selected Occupations in Michigan and the Mechanism for its Translation into Vocational Education Curricula: Section Report on Automobile Engine Mechanics.

ERIC Educational Resources Information Center

Battelle Memorial Inst., Columbus, OH. Columbus Labs.

The report is one of a series which supplements the overall report "Exploratory Study to Analyze New Skill Content in Selected Occupations in Michigan and the Mechanism for its Translation into Vocational Education Curricula". The present report presents detailed task analyses and results of employers skill requirements for auto mechanics. The…

Quiet Clean Short-haul Experimental Engine (QCSEE) Under-The-Wing (UTW) boiler plate nacelle and core exhaust nozzle design report

NASA Technical Reports Server (NTRS)

1976-01-01

The mechanical design of the boiler plate nacelle and core exhaust nozzle for the QCSEE under the wing engine is presented. The nacelle, which features interchangeable hard-wall and acoustic panels, is to be utilized in the initial engine testing to establish acoustic requirements for the subsequent composite nacelle as well as in the QCSEE over the wing engine configuration.

Investigation of performance deterioration of the CF6/JT9D, high-bypass ratio turbofan engines

NASA Technical Reports Server (NTRS)

Ziemianski, J. A.; Mehalic, C. M.

1980-01-01

The aircraft energy efficiency program within NASA is developing technology required to improve the fuel efficiency of commercial subsonic transport aricraft. One segment of this program includes engine diagnostics which is directed toward determining the sources and causes of performance deterioration in the Pratt and Whitney Aircraft JT9D and General Electric CF6 high-bypass ratio turbofan engines and developing technology for minimizing the performance losses. Results of engine performance deterioration investigations based on historical data, special engine tests, and specific tests to define the influence of flight loads and component clearances on performance are presented. The results of analysis of several damage mechanisms that contribute to performance deterioration such as blade tip rubs, airfoil surface roughness and erosion, and thermal distortion are also included. The significance of these damage mechanisms on component and overall engine performance is discussed.

The Role of Functionality in the Mental Representations of Engineering Students: Some Differences in the Early Stages of Expertise

ERIC Educational Resources Information Center

Moss, Jarrod; Kotovsky, Kenneth; Cagan, Jonathan

2006-01-01

As engineers gain experience and become experts in their domain, the structure and content of their knowledge changes. Two studies are presented that examine differences in knowledge representation among freshman and senior engineering students. The first study examines recall of mechanical devices and chunking of components, and the second…

Case Study of a Discontinued Start-Up Engineering Program: Critical Challenges and Lessons Learned

ERIC Educational Resources Information Center

Friess, Wilhelm A.

2017-01-01

The explanatory case study presented here analyzes the factors that have contributed to the failure of a start-up engineering program launched at an off-campus site, and aimed at imparting the first two years of the BSc Mechanical, Electrical, Computer and Civil Engineering utilizing an integrated curriculum. Findings indicate the root cause for…

PREFACE: International Conference on Applied Sciences 2015 (ICAS2015)

NASA Astrophysics Data System (ADS)

Lemle, Ludovic Dan; Jiang, Yiwen

2016-02-01

The International Conference on Applied Sciences ICAS2015 took place in Wuhan, China on June 3-5, 2015 at the Military Economics Academy of Wuhan. The conference is regularly organized, alternatively in Romania and in P.R. China, by Politehnica University of Timişoara, Romania, and Military Economics Academy of Wuhan, P.R. China, with the joint aims to serve as a platform for exchange of information between various areas of applied sciences, and to promote the communication between the scientists of different nations, countries and continents. The topics of the conference cover a comprehensive spectrum of issues from: >Economical Sciences and Defense: Management Sciences, Business Management, Financial Management, Logistics, Human Resources, Crisis Management, Risk Management, Quality Control, Analysis and Prediction, Government Expenditure, Computational Methods in Economics, Military Sciences, National Security, and others... >Fundamental Sciences and Engineering: Interdisciplinary applications of physics, Numerical approximation and analysis, Computational Methods in Engineering, Metallic Materials, Composite Materials, Metal Alloys, Metallurgy, Heat Transfer, Mechanical Engineering, Mechatronics, Reliability, Electrical Engineering, Circuits and Systems, Signal Processing, Software Engineering, Data Bases, Modeling and Simulation, and others... The conference gathered qualified researchers whose expertise can be used to develop new engineering knowledge that has applicability potential in Engineering, Economics, Defense, etc. The number of participants was 120 from 11 countries (China, Romania, Taiwan, Korea, Denmark, France, Italy, Spain, USA, Jamaica, and Bosnia and Herzegovina). During the three days of the conference four invited and 67 oral talks were delivered. Based on the work presented at the conference, 38 selected papers have been included in this volume of IOP Conference Series: Materials Science and Engineering. These papers present new research in the various fields of Materials Engineering, Mechanical Engineering, Computers Engineering, and Electrical Engineering. It's our great pleasure to present this volume of IOP Conference Series: Materials Science and Engineering to the scientific community to promote further research in these areas. We sincerely hope that the papers published in this volume will contribute to the advancement of knowledge in the respective fields.

The 18th Aerospace Mechanisms Symposium

NASA Technical Reports Server (NTRS)

1984-01-01

Topics concerning aerospace mechanisms, their functional performance, and design specifications are presented. Discussed subjects include the design and development of release mechanisms, actuators, linear driver/rate controllers, antenna and appendage deployment systems, position control systems, and tracking mechanisms for antennas and solar arrays. Engine design, spaceborne experiments, and large space structure technology are also examined.

Probabilistic Multi-Scale, Multi-Level, Multi-Disciplinary Analysis and Optimization of Engine Structures

NASA Technical Reports Server (NTRS)

Chamis, Christos C.; Abumeri, Galib H.

2000-01-01

Aircraft engines are assemblies of dynamically interacting components. Engine updates to keep present aircraft flying safely and engines for new aircraft are progressively required to operate in more demanding technological and environmental requirements. Designs to effectively meet those requirements are necessarily collections of multi-scale, multi-level, multi-disciplinary analysis and optimization methods and probabilistic methods are necessary to quantify respective uncertainties. These types of methods are the only ones that can formally evaluate advanced composite designs which satisfy those progressively demanding requirements while assuring minimum cost, maximum reliability and maximum durability. Recent research activities at NASA Glenn Research Center have focused on developing multi-scale, multi-level, multidisciplinary analysis and optimization methods. Multi-scale refers to formal methods which describe complex material behavior metal or composite; multi-level refers to integration of participating disciplines to describe a structural response at the scale of interest; multidisciplinary refers to open-ended for various existing and yet to be developed discipline constructs required to formally predict/describe a structural response in engine operating environments. For example, these include but are not limited to: multi-factor models for material behavior, multi-scale composite mechanics, general purpose structural analysis, progressive structural fracture for evaluating durability and integrity, noise and acoustic fatigue, emission requirements, hot fluid mechanics, heat-transfer and probabilistic simulations. Many of these, as well as others, are encompassed in an integrated computer code identified as Engine Structures Technology Benefits Estimator (EST/BEST) or Multi-faceted/Engine Structures Optimization (MP/ESTOP). The discipline modules integrated in MP/ESTOP include: engine cycle (thermodynamics), engine weights, internal fluid mechanics, cost, mission and coupled structural/thermal, various composite property simulators and probabilistic methods to evaluate uncertainty effects (scatter ranges) in all the design parameters. The objective of the proposed paper is to briefly describe a multi-faceted design analysis and optimization capability for coupled multi-discipline engine structures optimization. Results are presented for engine and aircraft type metrics to illustrate the versatility of that capability. Results are also presented for reliability, noise and fatigue to illustrate its inclusiveness. For example, replacing metal rotors with composites reduces the engine weight by 20 percent, 15 percent noise reduction, and an order of magnitude improvement in reliability. Composite designs exist to increase fatigue life by at least two orders of magnitude compared to state-of-the-art metals.

Quiet Clean Short-Haul Experimental Engine (QCSEE). Preliminary analyses and design report, volume 2

NASA Technical Reports Server (NTRS)

1974-01-01

The experimental and flight propulsion systems are presented. The following areas are discussed: engine core and low pressure turbine design; bearings and seals design; controls and accessories design; nacelle aerodynamic design; nacelle mechanical design; weight; and aircraft systems design.

Metal- matrix composite processing technologies for aircraft engine applications

NASA Astrophysics Data System (ADS)

Pank, D. R.; Jackson, J. J.

1993-06-01

Titanium metal-matrix composites (MMC) are prime candidate materials for aerospace applications be-cause of their excellent high-temperature longitudinal strength and stiffness and low density compared with nickel- and steel-base materials. This article examines the steps GE Aircraft Engines (GEAE) has taken to develop an induction plasma deposition (IPD) processing method for the fabrication of Ti6242/SiC MMC material. Information regarding process methodology, microstructures, and mechani-cal properties of consolidated MMC structures will be presented. The work presented was funded under the GE-Aircraft Engine IR & D program.

Application of directional blasting in mining and civil engineering, 1986

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chernigovskii, A.A.

1986-01-01

The author describes the mechanism of breaking mineral rocks through blasting and offers recommendations on the application of directional blasting in mining and civil engineering. He also introduces criteria for cost-effectiveness of transporting rock mass from stope to pile by means of energy of explosion. And, the book presents ballistic tables to be used in constructing the trajectory of movement of a rock fragment during blasting operations while taking into account the topography of the land. In this edition, the author presents a more detailed theoretical treatment on the mechanism of fragmentation of a monolithic or fissured rock mass throughmore » blasting.« less

Fast and Efficient Feature Engineering for Multi-Cohort Analysis of EHR Data.

PubMed

Ozery-Flato, Michal; Yanover, Chen; Gottlieb, Assaf; Weissbrod, Omer; Parush Shear-Yashuv, Naama; Goldschmidt, Yaara

2017-01-01

We present a framework for feature engineering, tailored for longitudinal structured data, such as electronic health records (EHRs). To fast-track feature engineering and extraction, the framework combines general-use plug-in extractors, a multi-cohort management mechanism, and modular memoization. Using this framework, we rapidly extracted thousands of features from diverse and large healthcare data sources in multiple projects.

Materials properties, loads, and stress analysis, Spartan REM: Appendix A

NASA Technical Reports Server (NTRS)

Marlowe, D. S.; West, E. J.

1984-01-01

The mechanical properties, load tests, and stress analysis of the Spartan Release Engagement Mechanism (REM) is presented. The fracture properties of the components of the unit are also discussed. Detailed engineering drawings are included.

Computer models and output, Spartan REM: Appendix B

NASA Technical Reports Server (NTRS)

Marlowe, D. S.; West, E. J.

1984-01-01

A computer model of the Spartan Release Engagement Mechanism (REM) is presented in a series of numerical charts and engineering drawings. A crack growth analysis code is used to predict the fracture mechanics of critical components.

Mechanisms, applications, and perspectives of antiviral RNA silencing in plants

PubMed Central

Garcia-Ruiz, Hernan; Ruiz, Mayra Teresa Garcia; Peralta, Sergio Manuel Gabriel; Gabriel, Cristina Betzabeth Miravel; El-Mounadi, Kautar

2017-01-01

Viral diseases of plants cause important economic losses due to reduction in crop quality and quantity to the point of threatening food security in some countries. Given the reduced availability of natural sources, genetic resistance to viruses has been successfully engineered for some plant-virus combinations. A sound understanding of the basic mechanisms governing plant-virus interactions, including antiviral RNA silencing, is the foundation to design better management strategies and biotechnological approaches to engineer and implement antiviral resistance in plants. In this review, we present current molecular models to explain antiviral RNA silencing and its application in basic plant research, biotechnology and genetic engineering. PMID:28890589

Comparison of TAPS Packages for Engineering

ERIC Educational Resources Information Center

Sidhu, S. Manjit

2008-01-01

Purpose: This paper aims to present the development of technology-assisted problem solving (TAPS) packages at University Tenaga Nasional (UNITEN). The project is the further work of the development of interactive multimedia based packages targeted for students having problems in understanding the subject of engineering mechanics dynamics.…

Multifunctional Collaborative Modeling and Analysis Methods in Engineering Science

NASA Technical Reports Server (NTRS)

Ransom, Jonathan B.; Broduer, Steve (Technical Monitor)

2001-01-01

Engineers are challenged to produce better designs in less time and for less cost. Hence, to investigate novel and revolutionary design concepts, accurate, high-fidelity results must be assimilated rapidly into the design, analysis, and simulation process. This assimilation should consider diverse mathematical modeling and multi-discipline interactions necessitated by concepts exploiting advanced materials and structures. Integrated high-fidelity methods with diverse engineering applications provide the enabling technologies to assimilate these high-fidelity, multi-disciplinary results rapidly at an early stage in the design. These integrated methods must be multifunctional, collaborative, and applicable to the general field of engineering science and mechanics. Multifunctional methodologies and analysis procedures are formulated for interfacing diverse subdomain idealizations including multi-fidelity modeling methods and multi-discipline analysis methods. These methods, based on the method of weighted residuals, ensure accurate compatibility of primary and secondary variables across the subdomain interfaces. Methods are developed using diverse mathematical modeling (i.e., finite difference and finite element methods) and multi-fidelity modeling among the subdomains. Several benchmark scalar-field and vector-field problems in engineering science are presented with extensions to multidisciplinary problems. Results for all problems presented are in overall good agreement with the exact analytical solution or the reference numerical solution. Based on the results, the integrated modeling approach using the finite element method for multi-fidelity discretization among the subdomains is identified as most robust. The multiple-method approach is advantageous when interfacing diverse disciplines in which each of the method's strengths are utilized. The multifunctional methodology presented provides an effective mechanism by which domains with diverse idealizations are interfaced. This capability rapidly provides the high-fidelity results needed in the early design phase. Moreover, the capability is applicable to the general field of engineering science and mechanics. Hence, it provides a collaborative capability that accounts for interactions among engineering analysis methods.

Assessment of the Mechanical Properties of Sisal Fiber-Reinforced Silty Clay Using Triaxial Shear Tests

PubMed Central

Wu, Yankai; Li, Yanbin; Niu, Bin

2014-01-01

Fiber reinforcement is widely used in construction engineering to improve the mechanical properties of soil because it increases the soil's strength and improves the soil's mechanical properties. However, the mechanical properties of fiber-reinforced soils remain controversial. The present study investigated the mechanical properties of silty clay reinforced with discrete, randomly distributed sisal fibers using triaxial shear tests. The sisal fibers were cut to different lengths, randomly mixed with silty clay in varying percentages, and compacted to the maximum dry density at the optimum moisture content. The results indicate that with a fiber length of 10 mm and content of 1.0%, sisal fiber-reinforced silty clay is 20% stronger than nonreinforced silty clay. The fiber-reinforced silty clay exhibited crack fracture and surface shear fracture failure modes, implying that sisal fiber is a good earth reinforcement material with potential applications in civil engineering, dam foundation, roadbed engineering, and ground treatment. PMID:24982951

Maintenance of Mechanical Equipment in Minnesota Schools, 1968 Survey.

ERIC Educational Resources Information Center

Larson, R. E.; Rust, L. W.

Results of a one-year research program to study maintenance procedures for operating mechanical equipment were based on the determination of--(1) the present condition and level of performance of operating mechanical equipment, (2) the problems encountered by school administrators and custodial engineers pertaining to operating mechanical…

Assessment of potential asbestos exposures from jet engine overhaul work.

PubMed

Mlynarek, S P; Van Orden, D R

2012-06-01

Asbestos fibers have been used in a wide variety of products and numerous studies have shown that exposures from the use or manipulation of these products can vary widely. Jet engines contained various components (gaskets, clamps, o-rings and insulation) that contained asbestos that potentially could release airborne fibers during routine maintenance or during an engine overhaul. To evaluate the potential exposures to aircraft mechanics, a Pratt & Whitney JT3D jet engine was obtained and overhauled by experienced mechanics using tools and work practices similar to those used since the time this engine was manufactured. This study has demonstrated that the disturbance of asbestos-containing gaskets, o-rings, and other types of asbestos-containing components, while performing overhaul work to a jet engine produces very few airborne fibers, and that virtually none of these aerosolized fibers is asbestos. The overhaul work was observed to be dirty and oily. The exposures to the mechanics and bystanders were several orders of magnitude below OSHA exposure regulations, both current and historic. The data presented underscore the lack of risk to the health of persons conducting this work and to other persons in proximity to it from airborne asbestos. Copyright © 2012 Elsevier Inc. All rights reserved.

The 11th Aerospace Mechanisms Symposium

NASA Technical Reports Server (NTRS)

1977-01-01

Various mechanisms in aerospace engineering were presented at this conference. Specifications, design, and use of spacecraft and missile components are discussed, such as tail assemblies, radiometers, magnetormeters, pins, reaction wheels, ball bearings, actuators, mirrors, nutation dampers, airfoils, solar arrays, etc.

Marine Engine Mechanics. Performance Objectives. Basic Course.

ERIC Educational Resources Information Center

Jones, Marion

Several intermediate performance objectives and corresponding criterion measures are presented for each of six terminal objectives for a two-semester course (2 hours daily) which provides training in the terminology, construction, and function of both two- and four-cycle fuel-air mixture internal combustion engines with emphasis on outboard marine…

General Mechanical Repair. Minor Automotive Maintenance. Volume 1. Teacher's Guide.

ERIC Educational Resources Information Center

East Texas State Univ., Commerce. Occupational Curriculum Lab.

Fourteen units on minor automotive maintenance are presented in this teacher's guide. The units are the following: introduction to minor automotive maintenance, shop safety, engine principles, fuel system operation and repair, electrical system, ignition system, lubrication system, engine cooling system, exhaust system, wheel bearings and tires,…

Mechatronics as a technological basis for an innovative learning environment in engineering

NASA Astrophysics Data System (ADS)

Garner, Gavin Thomas

Mechatronic systems that couple mechanical and electrical systems with the help of computer control are forcing a paradigm shift in the design, manufacture, and implementation of mechanical devices. The inherently interdisciplinary nature of these systems generates exciting new opportunities for developing a hands-on, inventive, and creativity-focused educational program while still embracing rigorous scientific fundamentals. The technologies associated with mechatronics are continually evolving (e.g., integrated circuit chips, miniature and new types of sensors, and state-of-the-art actuators). As a result, a mechatronics curriculum must prepare students to adapt along with these rapidly changing technologies---and perhaps even advance these technologies themselves. Such is the inspiring and uncharted new world that is presented for student exploration and experimentation in the University of Virginia's Mechatronics Laboratory. The underlying goal of this research has been to develop a framework for teaching mechatronics that helps students master fundamental concepts and build essential technical and analytical skills. To this end, two courses involving over fifty hours worth of technologically-innovative and educationally-effective laboratory experiments have been developed along with open-ended projects in response to the unique and new challenges associated with teaching mechatronics. These experiments synthesize an unprecedentedly vast array of skills from many different disciplines and enable students to haptically absorb the fundamental concepts involved in designing mechatronic systems. They have been optimized through several iterations to become highly efficient. Perspectives on the development of these courses and on the field of mechatronics in general are included. Furthermore, this dissertation demonstrates the integration of new technologies within a learning environment specifically designed to teach mechatronics to mechanical engineers. For mechanical engineering in particular, mechatronics poses considerable challenges, and necessitates a fundamental evolution in the understanding of the relationship between the various engineering disciplines. Consequently, this dissertation helps to define the role that mechatronics must play in mechanical engineering and presents unique laboratory experiments, creative projects, and modeling and simulation exercises as effective tools for teaching mechatronics to the modern mechanical engineering student.

Energy and technology review: Engineering modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cabayan, H.S.; Goudreau, G.L.; Ziolkowski, R.W.

1986-10-01

This report presents information concerning: Modeling Canonical Problems in Electromagnetic Coupling Through Apertures; Finite-Element Codes for Computing Electrostatic Fields; Finite-Element Modeling of Electromagnetic Phenomena; Modeling Microwave-Pulse Compression in a Resonant Cavity; Lagrangian Finite-Element Analysis of Penetration Mechanics; Crashworthiness Engineering; Computer Modeling of Metal-Forming Processes; Thermal-Mechanical Modeling of Tungsten Arc Welding; Modeling Air Breakdown Induced by Electromagnetic Fields; Iterative Techniques for Solving Boltzmann's Equations for p-Type Semiconductors; Semiconductor Modeling; and Improved Numerical-Solution Techniques in Large-Scale Stress Analysis.

Project-Based Manufacturing Engineering Practice at Ibaraki University and Its Outcomes

NASA Astrophysics Data System (ADS)

Yamasaki, Kazuhiko; Wang, Dong F.; Maekawa, Katsuhiro

The real world experience of manufacturing processes from an idea stage to a final product must be related to classroom lectures in mechanical engineering curriculum, including design, materials engineering, dynamics and control. Various challenges and difficulties encountered during the manufacturing engineering practice also let students recognize their creativity as well as what kinds of knowledge is missing. Awareness is the start of growth. In line with this principle we have carried out the mechanical engineering practice for 10 years. Some modifications toward “project-based practice” , however, have been made through manufacturing engineers’ real activities. Drawing and specification, process control, cost management, and role-sharing arrangement are stressed during the semester course. The present paper describes how it works and what is left to improve further, such as a refinement of themes and a coaching method for bringing out the hidden talent in students.

A sublimation heat engine

PubMed Central

Wells, Gary G.; Ledesma-Aguilar, Rodrigo; McHale, Glen; Sefiane, Khellil

2015-01-01

Heat engines are based on the physical realization of a thermodynamic cycle, most famously the liquid–vapour Rankine cycle used for steam engines. Here we present a sublimation heat engine, which can convert temperature differences into mechanical work via the Leidenfrost effect. Through controlled experiments, quantified by a hydrodynamic model, we show that levitating dry-ice blocks rotate on hot turbine-like surfaces at a rate controlled by the turbine geometry, temperature difference and solid material properties. The rotational motion of the dry-ice loads is converted into electric power by coupling to a magnetic coil system. We extend our concept to liquid loads, generalizing the realization of the new engine to both sublimation and the instantaneous vapourization of liquids. Our results support the feasibility of low-friction in situ energy harvesting from both liquids and ices. Our concept is potentially relevant in challenging situations such as deep drilling, outer space exploration or micro-mechanical manipulation. PMID:25731669

Controllability of Free-piston Stirling Engine/linear Alternator Driving a Dynamic Load

NASA Technical Reports Server (NTRS)

Kankam, M. David; Rauch, Jeffrey S.

1994-01-01

This paper presents the dynamic behavior of a Free-Piston Stirling Engine/linear alternator (FPSE/LA) driving a single-phase fractional horse-power induction motor. The controllability and dynamic stability of the system are discussed by means of sensitivity effects of variations in system parameters, engine controller, operating conditions, and mechanical loading on the induction motor. The approach used expands on a combined mechanical and thermodynamic formulation employed in a previous paper. The application of state-space technique and frequency domain analysis enhances understanding of the dynamic interactions. Engine-alternator parametric sensitivity studies, similar to those of the previous paper, are summarized. Detailed discussions are provided for parametric variations which relate to the engine controller and system operating conditions. The results suggest that the controllability of a FPSE-based power system is enhanced by proper operating conditions and built-in controls.

A sublimation heat engine.

PubMed

Wells, Gary G; Ledesma-Aguilar, Rodrigo; McHale, Glen; Sefiane, Khellil

2015-03-03

Heat engines are based on the physical realization of a thermodynamic cycle, most famously the liquid-vapour Rankine cycle used for steam engines. Here we present a sublimation heat engine, which can convert temperature differences into mechanical work via the Leidenfrost effect. Through controlled experiments, quantified by a hydrodynamic model, we show that levitating dry-ice blocks rotate on hot turbine-like surfaces at a rate controlled by the turbine geometry, temperature difference and solid material properties. The rotational motion of the dry-ice loads is converted into electric power by coupling to a magnetic coil system. We extend our concept to liquid loads, generalizing the realization of the new engine to both sublimation and the instantaneous vapourization of liquids. Our results support the feasibility of low-friction in situ energy harvesting from both liquids and ices. Our concept is potentially relevant in challenging situations such as deep drilling, outer space exploration or micro-mechanical manipulation.

Nanotechnology in the Regeneration of Complex Tissues

PubMed Central

Cassidy, John W.

2015-01-01

Modern medicine faces a growing crisis as demand for organ transplantations continues to far outstrip supply. By stimulating the body’s own repair mechanisms, regenerative medicine aims to reduce demand for organs, while the closely related field of tissue engineering promises to deliver “off-the-self” organs grown from patients’ own stem cells to improve supply. To deliver on these promises, we must have reliable means of generating complex tissues. Thus far, the majority of successful tissue engineering approaches have relied on macroporous scaffolds to provide cells with both mechanical support and differentiative cues. In order to engineer complex tissues, greater attention must be paid to nanoscale cues present in a cell’s microenvironment. As the extracellular matrix is capable of driving complexity during development, it must be understood and reproduced in order to recapitulate complexity in engineered tissues. This review will summarize current progress in engineering complex tissue through the integration of nanocomposites and biomimetic scaffolds. PMID:26097381

The Transport of Mass, Energy, and Entropy in Cryogenic Support Struts for Engineering Design

NASA Technical Reports Server (NTRS)

Elchert, J. P.

2012-01-01

Engineers working to understand and reduce cryogenic boil-off must solve a variety of transport problems. An important class of nonlinear problems involves the thermal and mechanical design of cryogenic struts. These classic problems are scattered about the literature and typically require too many resources to obtain. So, to save time for practicing engineers, the author presents this essay. Herein, a variety of new, old, and revisited analytical and finite difference solutions of the thermal problem are covered in this essay, along with commentary on approach and assumptions. This includes a few thermal radiation and conduction combined mode solutions with a discussion on insulation, optimum emissivity, and geometrical phenomenon. Solutions to cooling and heat interception problems are also presented, including a discussion of the entropy generation. The literature on the combined mechanical and thermal design of cryogenic support struts is reviewed with an introduction to the associated numerical methods.

The Transport of Mass, Energy, and Entropy in Cryogenic Support Struts for Engineering Design

NASA Technical Reports Server (NTRS)

Elchert, J. P.

2012-01-01

Engineers working to understand and reduce cryogenic boil-off must solve a. variety of transport problems. An important class of nonlinear problems involves the thermal and mechanical design of cryogenic struts. These classic problems are scattered about the literature and typically require too many resources to obtain. So, to save time for practicing engineers, the author presents this essay. Herein, a variety of new, old, and revisited analytical and finite difference solutions of the thermal problem are covered in this essay, along with commentary on approach and assumptions, This includes a few thermal radiation and conduction combined mode solution with a discussion on insulation, optimum emissivity, and geometrical phenomenon. Solutions to cooling and heat interception problems are also presented, including a discussion of the entropy generation. And the literature on the combined mechanical and thermal design of cryogenic support struts is reviewed with an introduction to the associated numerical methods.

Effect of soot on oil properties and wear of engine components

NASA Astrophysics Data System (ADS)

Green, D. A.; Lewis, R.

2007-09-01

The objective of the work outlined in this paper was to increase the understanding of the wear mechanisms that occur within a soot contaminated contact zone, to help in future development of a predictive wear model to assist in the automotive engine valve train design process. The paper builds on previous work by the author, through testing of different lubricants and increased levels of soot contamination. Wear testing has been carried out using specimens operating under realistic engine conditions, using a reciprocating test-rig specifically designed for this application, where a steel disc is held in a heated bath of oil and a steel ball is attached to a reciprocating arm (replicating a sliding elephant's foot valve train contact). Detailed analysis of the test specimens has been performed using scanning electron microscopy to identify wear features relating to the proposed wear mechanisms. Analysis of worn engine components from durability engine tests has also been carried out for a comparison between specimen tests and engine testing. To assist the understanding of the wear test results obtained, the physical properties of contaminated lubricants were investigated, through viscosity, traction and friction measurements. The results have revealed how varying lubrication conditions change the wear rate of engine components and determine the wear mechanism that dominates in specific situations. Testing has also shown the positive effects of advanced engine lubricants to reduce the amount of wear produced with soot present.

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

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 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...

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

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 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...

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

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 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...

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

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 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...

The Role of Hydroxide and Metal Concentration on the Viscoelastic Properties of Metal Coordinated Gels

NASA Astrophysics Data System (ADS)

Cazzell, Seth; Holten-Andersen, Niels

Nature uses metal binding amino acids to engineer mechanical properties. An example of this engineering can be found in the mussel byssal thread. This acellular thread contains reversible intermolecular protein-metal bonds, which allows the mussel to robustly anchor to rocks, while withstanding the mechanically demanding intertidal environment. Inspired by this metal-binding material, we present a synthetic hydrogel designed to mimic this bonding behavior. The mechanical properties of this hydrogel can be controlled independently by manipulating the amount of metal relative to the metal binding ligand, and the gel's pH. Here we report how high metal to ligand ratios and low pH can be used to induce the formation of a strong, slow relaxing gels. This gel has potential applications as an energy dissipating material, and furthers our understanding of the bio-inspired engineering techniques that are used to design viscoelastic soft materials. I was supported by the Department of Defense (DoD) through the National Defense Science & Engineering Graduate Fellowship (NDSEG) Program.

Active and passive interaction mechanism of smart materials for health monitoring of engineering structures: a review

NASA Astrophysics Data System (ADS)

Annamdas, Venu Gopal Madhav; Annamdas, Kiran Kumar

2009-03-01

Smart materials when interact with engineering structures, should have the capability to sense, measure, process, and detect any change in the selected variables (stress, damage) at critical locations. These smart materials can be classified into active and passive depending on the type of the structure, variables to be monitored, and interaction mechanism due to surface bonding or embedment. Some of the prominent smart materials are piezoelectric materials, micro fiber composite, polymers, shape memory alloys, electrostrictive and magnetostrictive materials, electrorheological and magnetorheological fluids and fiber optics. In addition, host structures do have the properties to support or repel the usage of smart materials inside or on it. This paper presents some of the most widely used smart materials and their interaction mechanism for structural health monitoring of engineering structures.

Performance and Durability of Environmental Barrier Coatings on SiC/SiC Ceramic Matrix Composites

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Harder, Bryan; Bhatt, Ramakrishna

2016-01-01

This presentation highlights advanced environmental barrier coating (EBC) and SiC-SiC Ceramic Matrix Composites (CMC) systems for next generation turbine engines. The emphasis will be placed on fundamental coating and CMC property evaluations; and the integrated system performance and degradation mechanisms in simulated laboratory turbine engine testing environments. Long term durability tests in laser rig simulated high heat flux the rmomechanical creep and fatigue loading conditions will also be presented. The results can help improve the future EBC-CMC system designs, validating the advanced EBC-CMC technologies for hot section turbine engine applications.

Summer Institute in Agricultural Mechanics Education, Southern Region, Proceedings (Blacksburg, Virginia, August 3-7, 1970).

ERIC Educational Resources Information Center

Virginia Polytechnic Inst. and State Univ., Blacksburg.

This summer institute emphasizes the establishment of minimum measurable standards of attainment in agricultural engineering phases of teacher education in agriculture. Speeches presented are: (1) "Where We Are in Agricultural Mechanics Education," by Alfred H. Krebs, (2) "Research Offerings for More Effective Teaching in Agricultural Mechanics,"…

A summary of NASA/Air Force full scale engine research programs using the F100 engine

NASA Technical Reports Server (NTRS)

Deskin, W. J.; Hurrell, H. G.

1979-01-01

A full scale engine research (FSER) program conducted with the F100 engine is presented. The program mechanism is described and the F100 test vehicles utilized are illustrated. Technology items were addressed in the areas of swirl augmentation, flutter phenomenon, advanced electronic control logic theory, strain gage technology and distortion sensitivity. The associated test programs are described. The FSER approach utilizes existing state of the art engine hardware to evaluate advanced technology concepts and problem areas. Aerodynamic phenomenon previously not considered by design systems were identified and incorporated into industry design tools.

Engineering Knowledge for Assistive Living

NASA Astrophysics Data System (ADS)

Chen, Liming; Nugent, Chris

This paper introduces a knowledge based approach to assistive living in smart homes. It proposes a system architecture that makes use of knowledge in the lifecycle of assistive living. The paper describes ontology based knowledge engineering practices and discusses mechanisms for exploiting knowledge for activity recognition and assistance. It presents system implementation and experiments, and discusses initial results.

SMS engineering design report

NASA Technical Reports Server (NTRS)

1976-01-01

The engineering design for the Shuttle Missions Simulator is presented in sections, with each section representing a subsystem development activity. Subsystems covered include: electrical power system; mechanical power system; main propellant and external tank; solid rocket booster; reaction control system; orbital maneuvering system; guidance, navigation, and control; data processing system; mission control center interface; and image display system.

Automotive Modules. Vocational Behavioral Objectives: A Guide for Individualizing Instruction.

ERIC Educational Resources Information Center

Westinghouse Learning Corp., New York, NY.

The curriculum guide deals with automotive repair skills at the secondary level of vocational education and industrial arts. It addresses the subject in behavioral terms, as prominent components of the career education concept. Presenting four skill modules, auto body repair, gas engine repair, service, and diesel engine mechanics, the objectives…

An overview of the Penn State Propulsion Engineering Research Center

NASA Technical Reports Server (NTRS)

Merkle, Charles L.

1991-01-01

An overview of the Penn State Propulsion Engineering Research Center is presented. The following subject areas are covered: research objectives and long term perspective of the Center; current status and operational philosophy; and brief description of Center projects (combustion, fluid mechanics and heat transfer, materials compatibility, turbomachinery, and advanced propulsion concepts).

From Tootsie Rolls to Broken Bones: An Innovative Approach for Active Learning in Mechanics of Materials

ERIC Educational Resources Information Center

Linsey, Julie; Talley, Austin; White, Christina; Jensen, Dan; Wood, Kristin

2009-01-01

Active learning enhances engineering education. This paper presents rationale, curriculum supplements, and an approach to active learning that may be seamlessly incorporated into a traditional lecture-based engineering class. A framework of educational theory that structures the active learning experiences and includes consideration of learning…

A Multicomponent Blend as a Diesel Fuel Surrogate for Compression Ignition Engine Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pei, Yuanjiang; Mehl, Marco; Liu, Wei

A mixture of n-dodecane and m-xylene is investigated as a diesel fuel surrogate for compression ignition engine applications. Compared to neat n-dodecane, this binary mixture is more representative of diesel fuel because it contains an alkyl-benzene which represents an important chemical class present in diesel fuels. A detailed multi-component mechanism for n-dodecane and m-xylene was developed by combining a previously developed n-dodecane mechanism with a recently developed mechanism for xylenes. The xylene mechanism is shown to reproduce experimental ignition data from a rapid compression machine and shock tube, speciation data from the jet stirred reactor and flame speed data. Thismore » combined mechanism was validated by comparing predictions from the model with experimental data for ignition in shock tubes and for reactivity in a flow reactor. The combined mechanism, consisting of 2885 species and 11754 reactions, was reduced to a skeletal mechanism consisting 163 species and 887 reactions for 3D diesel engine simulations. The mechanism reduction was performed using directed relation graph (DRG) with expert knowledge (DRG-X) and DRG-aided sensitivity analysis (DRGASA) at a fixed fuel composition of 77% of n-dodecane and 23% m-xylene by volume. The sample space for the reduction covered pressure of 1 – 80 bar, equivalence ratio of 0.5 – 2.0, and initial temperature of 700 – 1600 K for ignition. The skeletal mechanism was compared with the detailed mechanism for ignition and flow reactor predictions. Finally, the skeletal mechanism was validated against a spray flame dataset under diesel engine conditions documented on the Engine Combustion Network (ECN) website. These multi-dimensional simulations were performed using a Representative Interactive Flame (RIF) turbulent combustion model. Encouraging results were obtained compared to the experiments with regards to the predictions of ignition delay and lift-off length at different ambient temperatures.« less

46 CFR 12.15-13 - Deck engine mechanic.

Code of Federal Regulations, 2010 CFR

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...

46 CFR 12.15-13 - Deck engine mechanic.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 1 2012-10-01 2012-10-01 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...

46 CFR 12.15-13 - Deck engine mechanic.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 1 2013-10-01 2013-10-01 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...

46 CFR 12.15-13 - Deck engine mechanic.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 1 2011-10-01 2011-10-01 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...

NASA-UVA Light Aerospace Alloy and Structures Technology Program: LA(2)ST

NASA Technical Reports Server (NTRS)

Gangloff, Richard P.; Haviland, John K.; Herakovich, Carl T.; Pilkey, Walter D.; Pindera, Marek-Jerzy; Scully, John R.; Stoner, Glenn E.; Thornton, Earl A.; Wawner, Franklin E., Jr.; Wert, John A.

1993-01-01

The NASA-UVA Light Aerospace Alloy and Structures Technology (LA(2)ST) Program continues a high level of activity, with projects being conducted by graduate students and faculty advisors in the Departments of Materials Science and Engineering, Civil Engineering and Applied Mechanics, and Mechanical and Aerospace Engineering at the University of Virginia. This work is funded by the NASA-Langley Research Center under Grant NAG-1-745. We report on progress achieved between July 1 and December 31, 1992. The objective of the LA(2)ST Program is to conduct interdisciplinary graduate student research on the performance of next generation, light weight aerospace alloys, composites and thermal gradient structures in collaboration with NASA-Langley researchers. Specific technical objectives are presented for each research project. We generally aim to produce relevant data and basic understanding of material mechanical response, corrosion behavior, and microstructure; new monolithic and composite alloys; advanced processing methods; new solid and fluid mechanics analyses; measurement advances; and critically, a pool of educated graduate students for aerospace technologies.

On the dynamical vs. thermodynamical performance of a β-type Stirling engine

NASA Astrophysics Data System (ADS)

Reséndiz-Antonio, Margarita; Santillán, Moisés

2014-09-01

In this work we present a simple mathematical model for a β-type Stirling engine. Despite its simplicity, the model considers all the engine’s relevant thermodynamic and mechanical aspects. The dynamic behavior of the model equation of motion is analyzed in order to obtain the sufficient conditions for engine cycling and to study the stability of the stationary regime. The performance of the engine’s thermodynamic part is also investigated. As a matter of fact, we found that it corresponds to a Carnot engine.

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

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Mechanical engine order telegraph systems. 113.35-9... COMMUNICATION AND ALARM SYSTEMS AND EQUIPMENT Engine Order Telegraph Systems § 113.35-9 Mechanical engine order telegraph systems. (a) Each mechanical engine order telegraph system must consist of transmitters and...

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

PubMed

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 loading are used to tissue-engineer AC. Our goal is to provide a practical guide to their use and optimization of loading parameters. For each loading condition, we will also present and discuss benefits and limitations of bioreactor configurations that have been used. The intent is for this review to serve as a reference for including mechanical stimulation strategies as part of AC construct culture regimens.

A Noise-Assisted Reprogrammable Nanomechanical Logic Gate

DTIC Science & Technology

2009-01-01

effort toward scalable mechanical computation.1-4 This effort can be traced back to 1822 (at least), when Charles Babbage presented a mechanical...the ONR (N000140910963). REFERENCES AND NOTES (1) Babbage , H. P. Babbage’s Calculating Engines; Charles Babbage Reprint Series for the History of

Impact Mechanics

NASA Astrophysics Data System (ADS)

Stronge, W. J.

2004-03-01

Impact mechanics is concerned with the reaction forces that develop during a collision and the dynamic response of structures to these reaction forces. The subject has a wide range of engineering applications, from designing sports equipment to improving the crashworthiness of automobiles. This book develops several different methodologies for analysing collisions between structures. These range from rigid body theory for structures that are stiff and compact, to vibration and wave analyses for flexible structures. The emphasis is on low-speed impact where damage is local to the small region of contact between the colliding bodies. The analytical methods presented give results that are more robust or less sensitive to initial conditions than have been achieved hitherto. As a text, Impact Mechanics builds upon foundation courses in dynamics and strength of materials. It includes numerous industrially relevant examples and end-of-chapter homework problems drawn from industry and sports. Practising engineers will also find the methods presented in this book useful in calculating the response of a mechanical system to impact.

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

NASA Astrophysics Data System (ADS)

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.

A modular approach to creating large engineered cartilage surfaces.

PubMed

Ford, Audrey C; Chui, Wan Fung; Zeng, Anne Y; Nandy, Aditya; Liebenberg, Ellen; Carraro, Carlo; Kazakia, Galateia; Alliston, Tamara; O'Connell, Grace D

2018-01-23

Native articular cartilage has limited capacity to repair itself from focal defects or osteoarthritis. Tissue engineering has provided a promising biological treatment strategy that is currently being evaluated in clinical trials. However, current approaches in translating these techniques to developing large engineered tissues remains a significant challenge. In this study, we present a method for developing large-scale engineered cartilage surfaces through modular fabrication. Modular Engineered Tissue Surfaces (METS) uses the well-known, but largely under-utilized self-adhesion properties of de novo tissue to create large scaffolds with nutrient channels. Compressive mechanical properties were evaluated throughout METS specimens, and the tensile mechanical strength of the bonds between attached constructs was evaluated over time. Raman spectroscopy, biochemical assays, and histology were performed to investigate matrix distribution. Results showed that by Day 14, stable connections had formed between the constructs in the METS samples. By Day 21, bonds were robust enough to form a rigid sheet and continued to increase in size and strength over time. Compressive mechanical properties and glycosaminoglycan (GAG) content of METS and individual constructs increased significantly over time. The METS technique builds on established tissue engineering accomplishments of developing constructs with GAG composition and compressive properties approaching native cartilage. This study demonstrated that modular fabrication is a viable technique for creating large-scale engineered cartilage, which can be broadly applied to many tissue engineering applications and construct geometries. Copyright © 2017 Elsevier Ltd. All rights reserved.

Modeling and Simulation of a Free-Piston Engine with Electrical Generator Using HCCI Combustion

NASA Astrophysics Data System (ADS)

Alrbai, Mohammad

Free-piston engines have the potential to challenge the conventional crankshaft engines by their design simplicity and higher operational efficiency. Many studies have been performed to overcome the limitations of the free-piston devices especially the stability and control issues. The investigations within the presented dissertation aim to satisfy many objectives by employing the approach of chemical kinetics to present the combustion process in the free-piston engine. This approach in addition to its advanced accuracy over the empirical methods, it has many other features like the ability to analyze the engine emissions. The effect of the heat release rate (HRR) on the engine performance is considered as the main objective. Understanding the relation between the HRR and the piston dynamics helps in enhancing the system efficiency and identifying the parameters that affect the overall performance. The dissertation covers some other objectives that belongs to the combustion phasing. Exhaust gas recirculation (EGR), equivalence ratio and the intake temperature represent the main combustion parameters, which have been discussed in this dissertation. To obtain the stability in system performance, the model requires a proper controller to simulate the operation and manage the different system parameters; for this purpose, different controlling techniques have been employed. In addition, the dissertation considers some other topics like engine emissions, fuels and fuels mechanisms. The model of the study describes the processes within a single cylinder, two stroke engine, which includes springs to support higher frequencies, reduce cyclic variations and sustain the engine compression ratio. An electrical generator presents the engine load; the generator supports different load profiles and play the key role in controlling the system. The 1st law of thermodynamics and Newton's 2nd law are applied to couple the piston dynamics with the engine thermodynamics. The model governing equations represent a single zone perfectly stirred reactor (PSR) which contain a perfect mixing ideal gas mixture. The chemical kinetics approach is applied using Cantera/ MATLABRTM toolbox, which presents the combustion process. In this research, a homogenous charge compression ignition (HCCI) at different operational conditions is used. HCCI engines have high efficiencies and low emissions and can work within a wide range of fuels. The results have been presented in a multi-cycle simulation and a parametric study forms. In the case of the multi-cycle simulation, a 100 cycles of the engine operation have been simulated. The overall work that is delivered to the electrical generator presents 47% of the total fuel energy. The model indicates an average frequency of 125 Hz along the operational cycles. In order to eliminate the cyclic variations and ensure a continuous operation, a proportional derivative (PD) controller has been employed. The controller adjusts the generator load in order to minimize the difference between the bottom dead center (BDC) locations along the operation cycles. The PD controller shows weakness in achieving the full steady state operation, for this purpose; a proportional integral (PI) controller has been implemented. The PI controller seeks to achieve a specific compression ratio. The results show that; the PI controller indicates unique behavior after 15 cycles of operation where the model ended to fluctuate between two compression ratios only. The complex relation between the thermodynamics and the dynamics of the engine is the greatest challenge in examining the effectiveness of the PI controller. In the parametric investigations, EGR examinations show that NOx emission is reduced to less than the half, as 30 % of EGR is used; this occurs due to the EGR thermal and dilution effects, which cause significant drop in the peak bulk temperature and CO emissions as well. Under the applied conditions, EGR has the ability to raise the work output ratio by increasing the engine compression ratio. The examination of the EGR temperature on the engine performance indicates that cooled EGR charges have the advantage over the hot EGR mixtures on enhancing the work output ratio. At the same time, EGR temperature affects the NOx formation by speeding its instantaneous reactions rate. The dissertation includes a study of the effect of the intake temperature and the equivalence ratio (φ) as well. The increasing in the intake temperature reduce the time needed for ignition, but leads to a reduction in the work output ratio at the same time. Such results can help in studying high knock resistance fuels where ignition delay is a matter. In the case of the equivalence ratio, lean mixtures show efficiencies that exceed 50% compared to those at the stoichiometric conditions. In the case of the ultra-lean (φ<0.5) combustion, the results show that the NOx emission is with the minimal levels as well as the CO and the unburned hydrocarbons (UHC) emissions. Sensitivity analysis to the chemical kinetic mechanism for the fuel combustion has been presented also in the dissertation. Many mechanisms for different fuels have been investigated, for example; a modified mechanism for Methane that includes 36 species and 222 reactions has been compared with the full GRI 3.0 mechanism (53 species and 325 reactions). The results of this comparison indicate that the modified mechanism has the potential to replace the full one in some cases like in demonstrating the engine operation, but not in the engine emissions analysis.

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

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Mechanical engine order telegraph systems; application...-15 Mechanical engine order telegraph systems; application. If a mechanical engine order telegraph... cables or other mechanical limitations must not prevent the efficient operation of the system. ...

Turbine Engine Clearance Control Systems: Current Practices and Future Directions

NASA Astrophysics Data System (ADS)

Lattime, Scott B.; Steinetz, Bruce M.

2002-09-01

Improved blade tip sealing in the high pressure compressor (HPC) and high pressure turbine (HPT) can provide dramatic reductions in specific fuel consumption (SFC), time-on-wing, compressor stall margin, and engine efficiency as well as increased payload and mission range capabilities. Maintenance costs to overhaul large commercial gas turbine engines can easily exceed 1M. Engine removal from service is primarily due to spent exhaust gas temperature (EGT) margin caused mainly by the deterioration of HPT components. Increased blade tip clearance is a major factor in hot section component degradation. As engine designs continue to push the performance envelope with fewer parts and the market drives manufacturers to increase service life, the need for advanced sealing continues to grow. A review of aero gas turbine engine HPT performance degradation and the mechanisms that promote these losses are discussed. Benefits to the HPT due to improved clearance management are identified. Past and present sealing technologies are presented along with specifications for next generation engine clearance control systems.

Turbine Engine Clearance Control Systems: Current Practices and Future Directions

NASA Technical Reports Server (NTRS)

Lattime, Scott B.; Steinetz, Bruce M.

2002-01-01

Improved blade tip sealing in the high pressure compressor (HPC) and high pressure turbine (HPT) can provide dramatic reductions in specific fuel consumption (SFC), time-on-wing, compressor stall margin, and engine efficiency as well as increased payload and mission range capabilities. Maintenance costs to overhaul large commercial gas turbine engines can easily exceed $1M. Engine removal from service is primarily due to spent exhaust gas temperature (EGT) margin caused mainly by the deterioration of HPT components. Increased blade tip clearance is a major factor in hot section component degradation. As engine designs continue to push the performance envelope with fewer parts and the market drives manufacturers to increase service life, the need for advanced sealing continues to grow. A review of aero gas turbine engine HPT performance degradation and the mechanisms that promote these losses are discussed. Benefits to the HPT due to improved clearance management are identified. Past and present sealing technologies are presented along with specifications for next generation engine clearance control systems.

Systematic Engine Uprate Technology Development and Deployment for Pipeline Compressor Engines through Increased Torque

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dennis Schmitt; Daniel Olsen

2005-09-30

Three methods were utilized to analyze key components of slow-speed, large-bore, natural gas integral engines. These three methods included the application of computational fluid dynamics (CFD), dynamic modal analysis using finite element analysis (FEA), and a stress analysis method also using FEA. The CFD analysis focuses primarily on the fuel mixing in the combustion chamber of a TLA engine. Results indicate a significant increase in the homogeneity of the air and fuel using high-pressure fuel injection (HPFI) instead of standard low-pressure mechanical gas admission valve (MGAV). A modal analysis of three engine crankshafts (TLA-6, HBA-6, and GMV-10) is developed andmore » presented. Results indicate that each crankshaft has a natural frequency and corresponding speed that is well away from the typical engine operating speed. A frame stress analysis method is also developed and presented. Two different crankcases are examined. A TLA-6 crankcase is modeled and a stress analysis is performed. The method of dynamic load determination, model setup, and the results from the stress analysis are discussed. Preliminary results indicate a 10%-15% maximum increase in frame stress due to a 20% increase in HP. However, the high stress regions were localized. A new hydraulically actuated mechanical fuel valve is also developed and presented. This valve provides equivalent high-energy (supersonic) fuel injection comparable to a HPFI system, at 1/5th of the natural gas fuel pressure. This valve was developed in cooperation with the Dresser-Rand Corporation.« less

Fundamental heat transfer research for gas turbine engines

NASA Technical Reports Server (NTRS)

Metzger, D. E. (Editor)

1980-01-01

Thirty-seven experts from industry and the universities joined 24 NASA Lewis staff members in an exchange of ideas on trends in aeropropulsion research and technology, basic analyses, computational analyses, basic experiments, near-engine environment experiments, fundamental fluid mechanics and heat transfer, and hot technology as related to gas turbine engines. The workshop proceedings described include pre-workshop input from participants, presentations of current activity by the Lewis staff, reports of the four working groups, and a workshop summary.

Engineering-derived approaches for iPSC preparation, expansion, differentiation and applications.

PubMed

Li, Yang; Li, Ling; Chen, Zhi-Nan; Gao, Ge; Yao, Rui; Sun, Wei

2017-07-31

Remarkable achievements have been made since induced pluripotent stem cells (iPSCs) were first introduced in 2006. Compared with non-pluripotent stem cells, iPSC research faces several additional complexities, such as the choice of extracellular matrix proteins, growth and differentiation factors, as well as technical challenges related to self-renewal and directed differentiation. Overcoming these challenges requires the integration of knowledge and technologies from multiple fields including cell biology, biomaterial science, engineering, physics and medicine. Here, engineering-derived iPSC approaches are reviewed according to three aspects of iPSC studies: preparation, expansion, differentiation and applications. Engineering strategies, such as 3D systems establishment, cell-matrix mechanics and the regulation of biophysical and biochemical cues, together with engineering techniques, such as 3D scaffolds, cell microspheres and bioreactors, have been applied to iPSC studies and have generated insightful results and even mini-organs such as retinas, livers and intestines. Specific results are given to demonstrate how these approaches impact iPSC behavior, and related mechanisms are discussed. In addition, cell printing technologies are presented as an advanced engineering-derived approach since they have been applied in both iPSC studies and the construction of diverse tissues and organs. Further development and possible innovations of cell printing technologies are presented in terms of creating complex and functional iPSC-derived living tissues and organs.

Kinematic amplification strategies in plants and engineering

NASA Astrophysics Data System (ADS)

Charpentier, Victor; Hannequart, Philippe; Adriaenssens, Sigrid; Baverel, Olivier; Viglino, Emmanuel; Eisenman, Sasha

2017-06-01

While plants are primarily sessile at the organismal level, they do exhibit a vast array of movements at the organ or sub-organ level. These movements can occur for reasons as diverse as seed dispersal, nutrition, protection or pollination. Their advanced mechanisms generate a myriad of movement typologies, many of which are not fully understood. In recent years, there has been a renewal of interest in understanding the mechanical behavior of plants from an engineering perspective, with an interest in developing novel applications by up-sizing these mechanisms from the micro- to the macro-scale. This literature review identifies the main strategies used by plants to create and amplify movements and anatomize the most recent mechanical understanding of compliant engineering mechanics. The paper ultimately demonstrates that plant movements, rooted in compliance and multi-functionality, can effectively inspire better kinematic/adaptive structures and materials. In plants, the actuators and the deployment structures are fused into a single system. The understanding of those natural movements therefore starts with an exploration of mechanisms at the origins of movements. Plant movements, whether slow or fast, active or passive, reversible or irreversible, are presented and detailed for their mechanical significance. With a focus on displacement amplification, the most recent promising strategies for actuation and adaptive systems are examined with respect to the mechanical principles of shape morphing plant tissues.

Unstart phenomena induced by flow choking in scramjet inlet-isolators

NASA Astrophysics Data System (ADS)

Im, Seong-kyun; Do, Hyungrok

2018-02-01

A review of recent research outcomes in downstream flow choking-driven unstart is presented. Unstart is a flow phenomenon at the inlet that severely reduces the air mass flow rate through the engine, causing a loss of thrust and considerable transient mechanical loading. Therefore, unstart in a scramjet engine crucially affects the design and the operation range of hypersonic vehicles. Downstream flow choking is known to be one of the major mechanisms inducing inlet unstart, as confirmed by recent scramjet-powered flight tests. The current paper examines recent research progress in identifying flow choking mechanisms that trigger unstart. Three different flow choking mechanisms are discussed: flow blockage, mass addition, and heat release from combustion reactions. Current research outcomes on the characteristic of unstarting flows, such as transient and quasi-steady motions, are reviewed for each flow choking mechanism. The characteristics of unstarted flows are described including Buzzing phenomena and oscillatory motions of unstarted shockwaves. Then, the state-of-the-art methods to predict, detect, and control unstart are presented. The review suggests that further investigations with high-enthalpy ground facilities will aid understanding of heat release-driven unstart.

A Summary of the Naval Postgraduate School Research Program.

DTIC Science & Technology

1984-06-01

Administrative Sciences, Operations Research, National Security Affairs, Physics, Electrical Engineering , Meterology, Aeronautics, Oceanography and Mechanical ...Oceans and Major Seas -------------------------------- 290 DEPARTMENT OF MECHANICAL ENGINEERING 291 Mechanical Engineering Department Summary 293...in Buried Pipes Using Sulphur Hexaflouride as a Tracer Gas," American Society of Mechanical Engineers , The Journal of Engineering for Power

A simplified fuel control approach for low cost aircraft gas turbines

NASA Technical Reports Server (NTRS)

Gold, H.

1973-01-01

Reduction in the complexity of gas turbine fuel controls without loss of control accuracy, reliability, or effectiveness as a method for reducing engine costs is discussed. A description and analysis of hydromechanical approach are presented. A computer simulation of the control mechanism is given and performance of a physical model in engine test is reported.

Comparisons of Kinematics and Dynamics Simulation Software Tools

NASA Technical Reports Server (NTRS)

Shiue, Yeu-Sheng Paul

2002-01-01

Kinematic and dynamic analyses for moving bodies are essential to system engineers and designers in the process of design and validations. 3D visualization and motion simulation plus finite element analysis (FEA) give engineers a better way to present ideas and results. Marshall Space Flight Center (MSFC) system engineering researchers are currently using IGRIP from DELMIA Inc. as a kinematic simulation tool for discrete bodies motion simulations. Although IGRIP is an excellent tool for kinematic simulation with some dynamic analysis capabilities in robotic control, explorations of other alternatives with more powerful dynamic analysis and FEA capabilities are necessary. Kinematics analysis will only examine the displacement, velocity, and acceleration of the mechanism without considering effects from masses of components. With dynamic analysis and FEA, effects such as the forces or torques at the joint due to mass and inertia of components can be identified. With keen market competition, ALGOR Mechanical Event Simulation (MES), MSC visualNastran 4D, Unigraphics Motion+, and Pro/MECHANICA were chosen for explorations. In this study, comparisons between software tools were presented in terms of following categories: graphical user interface (GUI), import capability, tutorial availability, ease of use, kinematic simulation capability, dynamic simulation capability, FEA capability, graphical output, technical support, and cost. Propulsion Test Article (PTA) with Fastrac engine model exported from IGRIP and an office chair mechanism were used as examples for simulations.

Reuleaux models at St. Petersburg State University

NASA Astrophysics Data System (ADS)

Kuteeva, G. A.; Sinilshchikova, G. A.; Trifonenko, B. V.

2018-05-01

Franz Reuleaux (1829 - 1905) is a famous mechanical engineer, a Professor of the Berlin Royal Technical Academy. He became widely known as an engineer-scientist, a Professor and industrial consultant, education reformer and leader of the technical elite of Germany. He directed the design and manufacture of over 300 models of simple mechanisms. They were sold to many famous universities for pedagogical and scientific purposes. Today, the most complete set is at Cornell University, College of Engineering. In this article we discuss the history, the modern state and our using the Reuleaux models that survived at St. Petersburg State University for educational purposes. We present description of certain models and our electronic resource with these models. We provide the information of similar electronic resources from other universities.

Experimental and analytical study of ceramic-coated turbine-tip shroud seals for small turbine engines

NASA Technical Reports Server (NTRS)

Biesiadny, T. J.; Mcdonald, G. E.; Hendricks, R. C.; Little, J. K.; Robinson, R. A.; Klann, G. A.; Lassow, E. S.

1985-01-01

The results of an experimental and analytical evaluation of ceramic turbine tip shrouds within a small turbine engine operating environment are presented. The ceramic shrouds were subjected to 1001 cycles between idle and high power and steady-state conditions for a total of 57.8 engine hr. Posttest engine inspection revealed mud-flat surface cracking, which was attributed to microcracking under tension with crack penetration to the ceramic and bond coat interface. Sections and micrographs tend to corroborate the thesis. The engine test data provided input to a thermomechanical analysis to predict temperature and stress profiles throughout the ceramic gas-path seal. The analysis predicts cyclic thermal stresses large enough to cause the seal to fail. These stresses are, however, mitigated by inelastic behavior of the shroud materials and by the microfracturing that tensile stresses produce. Microfracturing enhances shroud longevity during early life but provides the failure mechanism during life but provides the failure mechanism during extended life when coupled with the time dependent inelastic materials effects.

Developing technology for surgery in the UK: a multidisciplinary meeting of engineers and surgeons.

PubMed

Taylor, G W

2007-03-01

There is an increasing necessity for surgeons and engineers to work together in order to target future technological developments at clinical need and cost-effectiveness. This is a report of two linked meetings with these objectives, held at the Institute of Mechanical Engineers, London, UK. The two meetings were organized by the same faculty members and held on consecutive days. Delegates included surgeons, academic mechanical engineers, researchers and industrial representatives. The programme was made up of varied presentations by surgeons and engineers as well as open discussion of the topics covered. Delegates were updated on the current state of surgical robotics in the UK in four surgical specialties; urology, neurosurgery, orthopaedics and ENT. This included clinical and experimental evidence, together with discussion of future advances. Minimally invasive surgery, real-time imaging and the development of more compact and cost effective surgical robots were identified as key areas for future research. Copyright 2006 John Wiley & Sons, Ltd.

Thermal engine driven heat pump for recovery of volatile organic compounds

DOEpatents

Drake, Richard L.

1991-01-01

The present invention relates to a method and apparatus for separating volatile organic compounds from a stream of process gas. An internal combustion engine drives a plurality of refrigeration systems, an electrical generator and an air compressor. The exhaust of the internal combustion engine drives an inert gas subsystem and a heater for the gas. A water jacket captures waste heat from the internal combustion engine and drives a second heater for the gas and possibly an additional refrigeration system for the supply of chilled water. The refrigeration systems mechanically driven by the internal combustion engine effect the precipitation of volatile organic compounds from the stream of gas.

Engine starting and stopping

NASA Astrophysics Data System (ADS)

Curnock, Barry

Different starter systems for jet engines are discussed: electric, cartridge, iso-propyl-nitrate, air, gas turbine, and hydraulic. The fuel system, ignition system, air flow control system, and actual starting mechanism of an air starter motor system are considered. The variation of engine parameters throughout a typical starting sequence are described, with reference to examples for an RB211-535 engine. Physical constraints on engine starting are considered: rotating stall, light up, the window between hang and stall, hang, compressor stall, and the effects of ambient conditions. The following are also discussed: contractual and airworthiness requirements; windmilling; inflight relighting; afterburning light up; combustion stability; and broken shafts. Graphics illustrating the above are presented.

United States Air Force Graduate Student Summer Support Program 1986. Program Technical Report. Volume 2

DTIC Science & Technology

1986-12-01

Engineering University of Wisconsin- Madison Mechanics, 1985 Dept. of Engineering Mechanics Specialty: Engineering Mechanics 1415 Johnson Drive Assigned: RPL... Madison , WI 53706 (608) 262-3990 Brian J. Doherty Degree: B.S.E., Bioenginnering, 1984 Duke University Specialty: Bloengineering Biomedical Engineering...Assigned: ML Kent, OH 44242 (216) 672-2246 Gregory L. Walker Degree: B.S., Engineering University of Wisconsin- Madison Mechanics, 1985 Engineering

Creating Learning Environment Connecting Engineering Design and 3D Printing

NASA Astrophysics Data System (ADS)

Pikkarainen, Ari; Salminen, Antti; Piili, Heidi

Engineering education in modern days require continuous development in didactics, pedagogics and used practical methods. 3D printing provides excellent opportunity to connect different engineering areas into practice and produce learning by doing applications. The 3D-printing technology used in this study is FDM (Fused deposition modeling). FDM is the most used 3D-printing technology by commercial numbers at the moment and the qualities of the technology makes it popular especially in academic environments. For achieving the best result possible, students will incorporate the principles of DFAM (Design for additive manufacturing) into their engineering design studies together with 3D printing. This paper presents a plan for creating learning environment for mechanical engineering students combining the aspects of engineering design, 3D-CAD learning and AM (additive manufacturing). As a result, process charts for carrying out the 3D printing process from technological point of view and design process for AM from engineering design point of view were created. These charts are used in engineering design education. The learning environment is developed to work also as a platform for Bachelor theses, work-training environment for students, prototyping service centre for cooperation partners and source of information for mechanical engineering education in Lapland University of Applied Sciences.

Real-time earthquake monitoring using a search engine method.

PubMed

Zhang, Jie; Zhang, Haijiang; Chen, Enhong; Zheng, Yi; Kuang, Wenhuan; Zhang, Xiong

2014-12-04

When an earthquake occurs, seismologists want to use recorded seismograms to infer its location, magnitude and source-focal mechanism as quickly as possible. If such information could be determined immediately, timely evacuations and emergency actions could be undertaken to mitigate earthquake damage. Current advanced methods can report the initial location and magnitude of an earthquake within a few seconds, but estimating the source-focal mechanism may require minutes to hours. Here we present an earthquake search engine, similar to a web search engine, that we developed by applying a computer fast search method to a large seismogram database to find waveforms that best fit the input data. Our method is several thousand times faster than an exact search. For an Mw 5.9 earthquake on 8 March 2012 in Xinjiang, China, the search engine can infer the earthquake's parameters in <1 s after receiving the long-period surface wave data.

Real-time earthquake monitoring using a search engine method

PubMed Central

Zhang, Jie; Zhang, Haijiang; Chen, Enhong; Zheng, Yi; Kuang, Wenhuan; Zhang, Xiong

2014-01-01

When an earthquake occurs, seismologists want to use recorded seismograms to infer its location, magnitude and source-focal mechanism as quickly as possible. If such information could be determined immediately, timely evacuations and emergency actions could be undertaken to mitigate earthquake damage. Current advanced methods can report the initial location and magnitude of an earthquake within a few seconds, but estimating the source-focal mechanism may require minutes to hours. Here we present an earthquake search engine, similar to a web search engine, that we developed by applying a computer fast search method to a large seismogram database to find waveforms that best fit the input data. Our method is several thousand times faster than an exact search. For an Mw 5.9 earthquake on 8 March 2012 in Xinjiang, China, the search engine can infer the earthquake’s parameters in <1 s after receiving the long-period surface wave data. PMID:25472861

Data Documentation for Navy Civilian Manpower Study,

DTIC Science & Technology

1986-09-01

Engineering 0830 Mechanical Engineer 0840 Nuclear Engineering 0850 Electrical Engineering 0855 Electronics Engineering 0856 Electronics ...OCCUPATIONAL LEVEL (DONOL) CODES DONOL code Title 1060 Engineering Drafting 1061 Electronics Technician w 1062 Engineering Technician 1063 Industrial...Architect 2314 Electrical Engineer 2315 Electronic Engineer 2316 Industrial Engineer 2317 Mechanical Engineer 2318

Multiscale Poly-(ϵ-caprolactone) Scaffold Mimicking Nonlinearity in Tendon Tissue Mechanics

PubMed Central

Banik, Brittany L.; Lewis, Gregory S.; Brown, Justin L.

2016-01-01

Regenerative medicine plays a critical role in the future of medicine. However, challenges remain to balance stem cells, biomaterial scaffolds, and biochemical factors to create successful and effective scaffold designs. This project analyzes scaffold architecture with respect to mechanical capability and preliminary mesenchymal stem cell response for tendon regeneration. An electrospun fiber scaffold with tailorable properties based on a “Chinese-fingertrap” design is presented. The unique criss-crossed fiber structures demonstrate non-linear mechanical response similar to that observed in native tendon. Mechanical testing revealed that optimizing the fiber orientation resulted in the characteristic “S”-shaped curve, demonstrating a toe region and linear elastic region. This project has promising research potential across various disciplines: vascular engineering, nerve regeneration, and ligament and tendon tissue engineering. PMID:27141530

Single and two-mode mechanical squeezing of an optically levitated nanodiamond via dressed-state coherence

NASA Astrophysics Data System (ADS)

Ge, Wenchao; Bhattacharya, M.

2016-10-01

Nonclassical states of macroscopic objects are promising for ultrasensitive metrology as well as testing quantum mechanics. In this work, we investigate dissipative mechanical quantum state engineering in an optically levitated nanodiamond. First, we study single-mode mechanical squeezed states by magnetically coupling the mechanical motion to a dressed three-level system provided by a nitrogen-vacancy center in the nanoparticle. Quantum coherence between the dressed levels is created via microwave fields to induce a two-phonon transition, which results in mechanical squeezing. Remarkably, we find that in ultrahigh vacuum quantum squeezing is achievable at room temperature with feedback cooling. For moderate vacuum, quantum squeezing is possible with cryogenic temperature. Second, we present a setup for two mechanical modes coupled to the dressed three levels, which results in two-mode squeezing analogous to the mechanism of the single-mode case. In contrast to previous works, our study provides a deterministic method for engineering macroscopic squeezed states without the requirement for a cavity.

Learning framework of “Integrating Techniques” for Solving Problems and Its Empirical Application in Doctoral Course in Mechanical Engineering

NASA Astrophysics Data System (ADS)

Otsuka, Yuichi; Ohta, Kazuhide; Noguchi, Hiroshi

The 21st century Center of Excellence (COE) program in Department of Mechanical Engineering Science at Kyushu University construct the training framework of learning “Integrating Techniques” by research presentations for students in different majors and accident analyses for practical cases by Ph.D course students. The training framework is composed of three processes : 1) Peer review among Ph.D course students for the presentations, 2) Instructions by teachers in order to improve the quality of the presentations based on the result of the peer-reviews, 3) Final evaluation for the improved presentations by teachers and the students. This research has elucidated the quantitative effectiveness of the framework by the evaluations using questionnaires for the presentations. Furthermore, the result of investigation for the course students has observed positive correlation between the significance of integration techniques and the enthusiasm for participating the course, which reveals the efficacy of the learning framework proposed.

A Hurricane for Physics Students.

ERIC Educational Resources Information Center

Mayo, Ned

1994-01-01

Describes how the study of a hurricane can be used to provide integrated basic mechanics in a first-year college course in engineering mechanics. Presents models that predict wind speed given surface eye pressure and several radial dimensions of the storm and calculate total kinetic energy once the wind speed is determined. (ZWH)

Development of Facilities for an Ocean Engineering Laboratory. Final Report.

ERIC Educational Resources Information Center

Nash, W. A.; And Others

A collection of seven laboratory facilities and processes dedicated to improving student understanding of the fundamental concepts associated with the structural mechanics of oceanic structures is described. Complete working drawings covering all mechanical and electrical aspects of these systems are presented so that the systems may be reproduced…

Protein-based hydrogels for tissue engineering

PubMed Central

Schloss, Ashley C.; Williams, Danielle M.; Regan, Lynne J.

2017-01-01

The tunable mechanical and structural properties of protein-based hydrogels make them excellent scaffolds for tissue engineering and repair. Moreover, using protein-based components provides the option to insert sequences associated with the promoting both cellular adhesion to the substrate and overall cell growth. Protein-based hydrogel components are appealing for their structural designability, specific biological functionality, and stimuli-responsiveness. Here we present highlights in the field of protein-based hydrogels for tissue engineering applications including design requirements, components, and gel types. PMID:27677513

Quiet Clean Short-haul Experimental Engine (QCSEE) UTW fan preliminary design

NASA Technical Reports Server (NTRS)

1975-01-01

High bypass geared turbofan engines and propulsion systems designed for short-haul passenger aircraft are described. The propulsion technology required for future externally blown flap aircraft with engines located both under the wing and over the wing is emphasized. The aerodynamic and mechanical preliminary design of the QCSEE under the wing 1.34 pressure ratio fan with variable blade pitch is presented. Design information is given for two pitch change actuation systems which will provide reverse thrust.

An experimental investigation of the aerodynamics and cooling of a horizontally-opposed air-cooled aircraft engine installation

NASA Technical Reports Server (NTRS)

Miley, S. J.; Cross, E. J., Jr.; Owens, J. K.; Lawrence, D. L.

1981-01-01

A flight-test based research program was performed to investigate the aerodynamics and cooling of a horizontally-opposed engine installation. Specific areas investigated were the internal aerodynamics and cooling mechanics of the installation, inlet aerodynamics, and exit aerodynamics. The applicable theory and current state of the art are discussed for each area. Flight-test and ground-test techniques for the development of the cooling installation and the solution of cooling problems are presented. The results show that much of the internal aerodynamics and cooling technology developed for radial engines are applicable to horizontally opposed engines. Correlation is established between engine manufacturer's cooling design data and flight measurements of the particular installation. Also, a flight-test method for the development of cooling requirements in terms of easily measurable parameters is presented. The impact of inlet and exit design on cooling and cooling drag is shown to be of major significance.

Variable valve timing in a homogenous charge compression ignition engine

DOEpatents

Lawrence, Keith E.; Faletti, James J.; Funke, Steven J.; Maloney, Ronald P.

2004-08-03

The present invention relates generally to the field of homogenous charge compression ignition engines, in which fuel is injected when the cylinder piston is relatively close to the bottom dead center position for its compression stroke. The fuel mixes with air in the cylinder during the compression stroke to create a relatively lean homogeneous mixture that preferably ignites when the piston is relatively close to the top dead center position. However, if the ignition event occurs either earlier or later than desired, lowered performance, engine misfire, or even engine damage, can result. The present invention utilizes internal exhaust gas recirculation and/or compression ratio control to control the timing of ignition events and combustion duration in homogeneous charge compression ignition engines. Thus, at least one electro-hydraulic assist actuator is provided that is capable of mechanically engaging at least one cam actuated intake and/or exhaust valve.

Datasets on demographic trends in enrollment into undergraduate engineering programs at Covenant University, Nigeria.

PubMed

Popoola, Segun I; Atayero, Aderemi A; Badejo, Joke A; Odukoya, Jonathan A; Omole, David O; Ajayi, Priscilla

2018-06-01

In this data article, we present and analyze the demographic data of undergraduates admitted into engineering programs at Covenant University, Nigeria. The population distribution of 2649 candidates admitted into Chemical Engineering, Civil Engineering, Computer Engineering, Electrical and Electronics Engineering, Information and Communication Engineering, Mechanical Engineering, and Petroleum Engineering programs between 2002 and 2009 are analyzed by gender, age, and state of origin. The data provided in this data article were retrieved from the student bio-data submitted to the Department of Admissions and Student Records (DASR) and Center for Systems and Information Services (CSIS) by the candidates during the application process into the various engineering undergraduate programs. These vital information is made publicly available, after proper data anonymization, to facilitate empirical research in the emerging field of demographics analytics in higher education. A Microsoft Excel spreadsheet file is attached to this data article and the data is thoroughly described for easy reuse. Descriptive statistics and frequency distributions of the demographic data are presented in tables, plots, graphs, and charts. Unrestricted access to these demographic data will facilitate reliable and evidence-based research findings for sustainable education in developing countries.

Comparing Composites.

ERIC Educational Resources Information Center

Mathras, Michael S.

1993-01-01

Presents an activity that models the work of chemical engineers. Students design, fabricate, and perform mechanical tests on plaster matrix composites and compare the strength to mass ratios of several products. (PR)

An accurate and efficient method for piezoelectric coated functional devices based on the two-dimensional Green’s function for a normal line force and line charge

NASA Astrophysics Data System (ADS)

Hou, Peng-Fei; Zhang, Yang

2017-09-01

Because most piezoelectric functional devices, including sensors, actuators and energy harvesters, are in the form of a piezoelectric coated structure, it is valuable to present an accurate and efficient method for obtaining the electro-mechanical coupling fields of this coated structure under mechanical and electrical loads. With this aim, the two-dimensional Green’s function for a normal line force and line charge on the surface of coated structure, which is a combination of an orthotropic piezoelectric coating and orthotropic elastic substrate, is presented in the form of elementary functions based on the general solution method. The corresponding electro-mechanical coupling fields of this coated structure under arbitrary mechanical and electrical loads can then be obtained by the superposition principle and Gauss integration. Numerical results show that the presented method has high computational precision, efficiency and stability. It can be used to design the best coating thickness in functional devices, improve the sensitivity of sensors, and improve the efficiency of actuators and energy harvesters. This method could be an efficient tool for engineers in engineering applications.

NASA-UVA light aerospace alloy and structures technology program (LA2ST)

NASA Technical Reports Server (NTRS)

Gangloff, Richard P.

1992-01-01

The NASA-UVa Light Aerospace Alloy and Structure Technology (LAST) Program continues to maintain a high level of activity, with projects being conducted by graduate students and faculty advisors in the Departments of Materials Science and Engineering, Civil Engineering and Applied Mechanics, and Mechanical and Aerospace Engineering at the University of Virginia. This work is funded by the NASA-Langley Research Center under Grant NAG-1-745. Here, we report on progress achieved between January 1 and June 30, 1992. The objectives of the LA2ST Program is to conduct interdisciplinary graduate student research on the performance of the next generation, light weight aerospace alloys, composites and thermal gradient structures in collaboration with Langley researchers. Technical objectives are established for each research project. We aim to produce relevant data and basic understanding of material mechanical response, corrosion behavior, and microstructure; new monolithic and composite alloys; advanced processing methods; new solid and fluid mechanics analyses; measurement advances; and critically, a pool of educated graduate students for aerospace technologies. The accomplishments presented in this report cover topics including: (1) Mechanical and Environmental Degradation Mechanisms in Advance Light Metals and Composites; (2) Aerospace Materials Science; (3) Mechanics of Materials and Composites for Aerospace Structures; and (4) Thermal Gradient Structures.

Mechanism Design Principle for Optical-Precision, Deployable Instruments

NASA Technical Reports Server (NTRS)

Lake, Mark S.; Hachkowski, M. Roman

2000-01-01

The present paper is intended to be a guide for the design of 'microdynamically quiet' deployment mechanisms for optical-precision structures, such as deployable telescope mirrors and optical benches. Many of the guidelines included herein come directly from the field of optomechanical engineering, and are neither newly developed guidelines nor are they uniquely applicable to high-precision deployment mechanisms. However, the application of these guidelines to the design of deployment mechanisms is a rather new practice, so efforts are made herein to illustrate the process through the discussion of specific examples. The present paper summarizes a more extensive set of design guidelines for optical-precision mechanisms that are under development.

Microwave-Assisted Ignition for Improved Internal Combustion Engine Efficiency

NASA Astrophysics Data System (ADS)

DeFilippo, Anthony Cesar

The ever-present need for reducing greenhouse gas emissions associated with transportation motivates this investigation of a novel ignition technology for internal combustion engine applications. Advanced engines can achieve higher efficiencies and reduced emissions by operating in regimes with diluted fuel-air mixtures and higher compression ratios, but the range of stable engine operation is constrained by combustion initiation and flame propagation when dilution levels are high. An advanced ignition technology that reliably extends the operating range of internal combustion engines will aid practical implementation of the next generation of high-efficiency engines. This dissertation contributes to next-generation ignition technology advancement by experimentally analyzing a prototype technology as well as developing a numerical model for the chemical processes governing microwave-assisted ignition. The microwave-assisted spark plug under development by Imagineering, Inc. of Japan has previously been shown to expand the stable operating range of gasoline-fueled engines through plasma-assisted combustion, but the factors limiting its operation were not well characterized. The present experimental study has two main goals. The first goal is to investigate the capability of the microwave-assisted spark plug towards expanding the stable operating range of wet-ethanol-fueled engines. The stability range is investigated by examining the coefficient of variation of indicated mean effective pressure as a metric for instability, and indicated specific ethanol consumption as a metric for efficiency. The second goal is to examine the factors affecting the extent to which microwaves enhance ignition processes. The factors impacting microwave enhancement of ignition processes are individually examined, using flame development behavior as a key metric in determining microwave effectiveness. Further development of practical combustion applications implementing microwave-assisted spark technology will benefit from predictive models which include the plasma processes governing the observed combustion enhancement. This dissertation documents the development of a chemical kinetic mechanism for the plasma-assisted combustion processes relevant to microwave-assisted spark ignition. The mechanism includes an existing mechanism for gas-phase methane oxidation, supplemented with electron impact reactions, cation and anion chemical reactions, and reactions involving vibrationally-excited and electronically-excited species. Calculations using the presently-developed numerical model explain experimentally-observed trends, highlighting the relative importance of pressure, temperature, and mixture composition in determining the effectiveness of microwave-assisted ignition enhancement.

Fracture mechanics methodology: Evaluation of structural components integrity

NASA Astrophysics Data System (ADS)

Sih, G. C.; de Oliveira Faria, L.

1984-09-01

The application of fracture mechanics to structural-design problems is discussed in lectures presented in the AGARD Fracture Mechanics Methodology course held in Lisbon, Portugal, in June 1981. The emphasis is on aeronautical design, and chapters are included on fatigue-life prediction for metals and composites, the fracture mechanics of engineering structural components, failure mechanics and damage evaluation of structural components, flaw-acceptance methods, and reliability in probabilistic design. Graphs, diagrams, drawings, and photographs are provided.

Evaluation of Separation Mechanism Design for the Orion/Ares Launch Vehicle

NASA Technical Reports Server (NTRS)

Konno, Kevin E.; Catalano, Daniel A.; Krivanek, Thomas M.

2008-01-01

As a part of the preliminary design work being performed for the Orion vehicle, the Orion to Spacecraft Adaptor (SA) separation mechanism mechanism was analyzed and sized, with findings presented here. Sizing is based on worst case abort condition as a result of an anomaly driving the launch vehicle engine thrust vector control hard-over causing a severe vehicle pitch over. This worst case scenario occurs just before Upper Stage Main Engine Cut-Off (MECO) when the vehicle is the lightest and the damping effect due to propellant slosh has been reduced to a minimum. To address this scenario and others, two modeling approaches were invoked. The first approach was a detailed Simulink model to quickly assess the Service Module Engine nozzle to SA clearance for a given separation mechanism. The second approach involved the generation of an Automatic Dynamic Analysis of Mechanical Systems (ADAMS) model to assess secondary effects due to mass centers of gravity that were slightly off the vehicle centerline. It also captured any interference between the Solar Arrays and the Spacecraft Adapter. A comparison of modeling results and accuracy are discussed. Most notably, incorporating a larger SA flange diameter allowed for a natural separation of the Orion and its engine nozzle even at relatively large pitch rates minimizing the kickoff force. Advantages and disadvantages of the Simulink model vs. a full geometric ADAMS model are discussed as well.

Free Fall Misconceptions: Results of a Graph Based Pre-Test of Sophomore Civil Engineering Students

ERIC Educational Resources Information Center

Montecinos, Alicia M.

2014-01-01

A partially unusual behaviour was found among 14 sophomore students of civil engineering who took a pre test for a free fall laboratory session, in the context of a general mechanics course. An analysis contemplating mathematics models and physics models consistency was made. In all cases, the students presented evidence favoring a correct free…

Chemical Engineers Go to the Movies (Stimulating Problems for the Contemporary Undergraduate Student)

ERIC Educational Resources Information Center

Smart, Jimmy L.

2007-01-01

In this article, the author presents five problems that are representative of some of the "movie problems" that he has used on tests in various courses, including reactor design, heat transfer, mass transfer, engineering economics, and fluid mechanics. These problems tend to be open-ended. They can be challenging and can often be worked a variety…

FOREWORD: 9th Curtin University of Technology Science and Engineering International Conference 2014 (CUTSE2014)

NASA Astrophysics Data System (ADS)

Chieng Chen, Vincent Lee

2015-04-01

A very warm welcome to all participants of the 9th Curtin University Technology, Science and Engineering (CUTSE) Conference 2014. This annual conference dates back to 2006 when the first Curtin University of Technology Science and Engineering (CUTSE) Conference was held in Curtin University, Miri Sarawak. CUTSE Conference was initially intended for Curtin's undergraduates such that they are able to experience the presentation of their work in a conference environment. As time passes and following the urge of knowledge dissemination, CUTSE Conference is hence open to public. This year the Department of Mechanical Engineering has been given the honour to organize the 9th CUTSE Conference. It has been a pleasure to watch CUTSE grow from strength to strength over the years. This year, our theme is "Discovering, Innovating and Engineering". We hope that it is in this spirit that CUTSE participants may align their respective work, such that we all aim for a greater and better implementation of "Discovering, Innovating and Engineering". The 9th CUTSE Conference 2014 is an excellent avenue for researchers, engineers, scientists, academicians, professionals from industry and students to share their research findings and initiate further collaborations in their respective fields. Parallel sessions in Mechanical, Electrical, Computer, Civil and Chemical engineering as well as the sciences will be hosted over a period of two days. Each year, the conference attracts participation from a number of countries in addition to Malaysia and Australia. In addition, student participants will get the opportunity to present their research projects and gain valuable feedback from industry professionals. This year the Conference will be organised by the Department of Mechanical Engineering of Curtin Sarawak's School of Engineering and Science in collaboration with The Institute of Engineers Malaysia, Miri Branch. On behalf of the organizing committee, I would like to thank this year's sponsors and supporters. We appreciate your support for CUTSE 2014 and in research and development, and your foresight in nurturing cutting edge research into industrial applications. CUTSE 2014 would not be possible without the dedicated work and efforts of the organizing committee, who worked tirelessly in all aspects of the conference organization. I thank you for your hard work and commitment towards making CUTSE 2014 a success. Selamat Datai (Welcome) and enjoy the conference. Dr Vincent Lee Chieng Chen Organizing Chairperson, 9th CUTSE Conference 2014

Standardized Curriculum for Diesel Engine Mechanics.

ERIC Educational Resources Information Center

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…

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

NASA Astrophysics Data System (ADS)

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 thanks to the expert reviewers who have spared their time reviewing the papers. We also highly appreciate the assistance offered by many volunteers in the preparation of the conference proceedings. All papers in ICMER 2011 have the opportunity to be published in IOP Conference Series: Materials Science and Engineering, (indexed by Scopus, Ei Compendex, Inspec), International Journal of Automotive and Mechanical Engineering (IJAME) and Journal of Mechanical Engineering and Sciences (JMES). Professor Dr Hj Rosli Abu Bakar Chairman ICMER 2011

Ramin Faramarzi | NREL

Science.gov Websites

Ramin Faramarzi Photo of Ramin Faramarzi Ramin Faramarzi Researcher V-Mechanical Engineering Engineering, California State University B.S. Mechanical Engineering, North Carolina State University articles and is a registered mechanical engineer in the state of California. Education M.S. Mechanical

Characterizing Strain Variation in Engineered E. coli Using a Multi-Omics-Based Workflow

DOE PAGES

Brunk, Elizabeth; George, Kevin W.; Alonso-Gutierrez, Jorge; ...

2016-05-19

Understanding the complex interactions that occur between heterologous and native biochemical pathways represents a major challenge in metabolic engineering and synthetic biology. We present a workflow that integrates metabolomics, proteomics, and genome-scale models of Escherichia coli metabolism to study the effects of introducing a heterologous pathway into a microbial host. This workflow incorporates complementary approaches from computational systems biology, metabolic engineering, and synthetic biology; provides molecular insight into how the host organism microenvironment changes due to pathway engineering; and demonstrates how biological mechanisms underlying strain variation can be exploited as an engineering strategy to increase product yield. As a proofmore » of concept, we present the analysis of eight engineered strains producing three biofuels: isopentenol, limonene, and bisabolene. Application of this workflow identified the roles of candidate genes, pathways, and biochemical reactions in observed experimental phenomena and facilitated the construction of a mutant strain with improved productivity. The contributed workflow is available as an open-source tool in the form of iPython notebooks.« less

Suitability of a PLCL fibrous scaffold for soft tissue engineering applications: A combined biological and mechanical characterisation.

PubMed

Laurent, Cédric P; Vaquette, Cédryck; Liu, Xing; Schmitt, Jean-François; Rahouadj, Rachid

2018-04-01

Poly(lactide-co-ε-caprolactone) (PLCL) has been reported to be a good candidate for tissue engineering because of its good biocompatibility. Particularly, a braided PLCL scaffold (PLL/PCL ratio = 85/15) has been recently designed and partially validated for ligament tissue engineering. In the present study, we assessed the in vivo biocompatibility of acellular and cellularised scaffolds in a rat model. We then determined its in vitro biocompatibility using stem cells issued from both bone marrow and Wharton Jelly. From a biological point of view, the scaffold was shown to be suitable for tissue engineering in all these cases. Secondly, while the initial mechanical properties of this scaffold have been previously reported to be adapted to load-bearing applications, we studied the evolution in time of the mechanical properties of PLCL fibres due to hydrolytic degradation. Results for isolated PLCL fibres were extrapolated to the fibrous scaffold using a previously developed numerical model. It was shown that no accumulation of plastic strain was to be expected for a load-bearing application such as anterior cruciate ligament tissue engineering. However, PLCL fibres exhibited a non-expected brittle behaviour after two months. This may involve a potential risk of premature failure of the scaffold, unless tissue growth compensates this change in mechanical properties. This combined study emphasises the need to characterise the properties of biomaterials in a pluridisciplinary approach, since biological and mechanical characterisations led in this case to different conclusions concerning the suitability of this scaffold for load-bearing applications.

Expose Mechanical Engineering Students to Biomechanics Topics

ERIC Educational Resources Information Center

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.…

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

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 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...

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

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 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...

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

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 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...

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

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 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...

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

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 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...

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

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 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...

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

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 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...

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

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 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...

Modeling mechanical interactions in growing populations of rod-shaped bacteria

NASA Astrophysics Data System (ADS)

Winkle, James J.; Igoshin, Oleg A.; Bennett, Matthew R.; Josić, Krešimir; Ott, William

2017-10-01

Advances in synthetic biology allow us to engineer bacterial collectives with pre-specified characteristics. However, the behavior of these collectives is difficult to understand, as cellular growth and division as well as extra-cellular fluid flow lead to complex, changing arrangements of cells within the population. To rationally engineer and control the behavior of cell collectives we need theoretical and computational tools to understand their emergent spatiotemporal dynamics. Here, we present an agent-based model that allows growing cells to detect and respond to mechanical interactions. Crucially, our model couples the dynamics of cell growth to the cell’s environment: Mechanical constraints can affect cellular growth rate and a cell may alter its behavior in response to these constraints. This coupling links the mechanical forces that influence cell growth and emergent behaviors in cell assemblies. We illustrate our approach by showing how mechanical interactions can impact the dynamics of bacterial collectives growing in microfluidic traps.

Thermal-Mechanical Fatigue Testing of a Titanium-Aluminide Alloy.

DTIC Science & Technology

1987-12-01

DIMSTRIBUTION STA Approved for pubi robing e% dQ *- AFIT/GAB/AA/87D-18 THERMAL-MECHANICAL FATIGUE TESTING OF A TITANIUM - ALUMINIDE ALLOY THESIS John J...THERMAL-MECHANICAL FATIGUE TESTING OF A TITANIUM - ALUMINIDE ALLOY THESIS Presented to the Faculty of the School of Engineering of the Air Force Institute...develop a Thermal-Mechanical Fatigue (TMF) testing system for titanium - aluminide compact tension specimens. I could not have accomplished this without the

Low-intensity pulsed ultrasound in dentofacial tissue engineering.

PubMed

Tanaka, Eiji; Kuroda, Shingo; Horiuchi, Shinya; Tabata, Akira; El-Bialy, Tarek

2015-04-01

Oral and maxillofacial diseases affect millions of people worldwide and hence tissue engineering can be considered an interesting and clinically relevant approach to regenerate orofacial tissues after being affected by different diseases. Among several innovations for tissue regeneration, low-intensity pulsed ultrasound (LIPUS) has been used extensively in medicine as a therapeutic, operative, and diagnostic tool. LIPUS is accepted to promote bone fracture repair and regeneration. Furthermore, the effect of LIPUS on soft tissues regeneration has been paid much attention, and many studies have performed to evaluate the potential use of LIPUS to tissue engineering soft tissues. The present article provides an overview about the status of LIPUS stimulation as a tool to be used to enhance regeneration/tissue engineering. This review consists of five parts. Part 1 is a brief introduction of the acoustic description of LIPUS and mechanical action. In Part 2, biological problems in dentofacial tissue engineering are proposed. Part 3 explores biologic mechanisms of LIPUS to cells and tissues in living body. In Part 4, the effectiveness of LIPUS on cell metabolism and tissue regeneration in dentistry are summarized. Finally, Part 5 relates the possibility of clinical application of LIPUS in orthodontics. The present review brings out better understanding of the bioeffect of LIPUS therapy on orofacial tissues which is essential to the successful integration of management remedies for tissue regeneration/engineering. To develop an evidence-based approach to clinical management and treatment of orofacial degenerative diseases using LIPUS, we would like to be in full pursuit of LIPUS biotherapy. Still, there are many challenges for this relatively new strategy, but the up to date achievements using it promises to go far beyond the present possibilities.

Wernher von Braun

NASA Image and Video Library

1965-11-05

In this photograph, Marshall Space Flight Center Director, Dr. Wernher von Braun, presents a Co-Inventor’s award to MSFC employee Martin Hall of the Mechanical Engineering Laboratory during the NASA Anniversary ceremony.

Outstanding student paper award at the 1996 Fall Meeting

NASA Astrophysics Data System (ADS)

The Planetology Section presented an Outstanding Student Paper Award at the AGU 1996 Fall Meeting in San Francisco, California, in December 1996. Elissa Koenig, presented a poster entitled “Mapping and Modeling of Radial Fracture Patterns on Venus.” Koenig graduated summa cum laude from Princeton University in 1991 with a B.S.E. form the Geological Engineering Program. She then spent a year as a Fulbright Scholar at the University of Auckland, New Zealand, where she studied the fluid dynamics of geyser eruptions. Elissa joined the Geomechanics Research Group at Stanford University in 1993 as an NSF Graduate Fellow, minoring in mechanical engineering. Her Ph.D. dissertation, titled “The Mechanics of Brittle Fracture and Faulting Venus,” explores the processes of both radial dike emplacement and strike-slip faulting.

On the possibility of producing piston pins for diesel engines from steel 18KhGT with the use of mechanical and chemical heat treatment

NASA Astrophysics Data System (ADS)

Zolot'ko, V. A.

1997-06-01

At the present time pisto pins of highly loaded diesel engines are produced by mechanical treatment from tube preforms of steel 12KhN3A and carburized by subsequent heat treatment. The high cost of domestic steel and the absence of preforms of the requisite size make it necessary to choose a less scare material and develop a treatment process that would provide the requisite operational characteristics of the parts. The present work is devoted to a study of the possibility of using for the purpose steel 18KhGT in a state of substructural toughening created by cold plastic straining (CPS) and a stabilizing heat treatment with subsequent ion nitriding.

Recent Cooperative Research Activities of HDD and Flexible Media Transport Technologies in Japan

NASA Astrophysics Data System (ADS)

Ono, Kyosuke

This paper presents the recent status of industry-university cooperative research activities in Japan on the mechatronics of information storage and input/output equipment. There are three research committees for promoting information exchange on technical problems and research topics of head-disk interface in hard disk drives (HDD), flexible media transport and image printing processes which are supported by the Japan Society of Mechanical Engineering (JSME), the Japanese Society of Tribologists (JAST) and the Japan Society of Precision Engineering (JSPE). For hard disk drive technology, the Storage Research Consortium (SRC) is supporting more than 40 research groups in various different universities to perform basic research for future HDD technology. The past and present statuses of these activities are introduced, particularly focusing on HDD and flexible media transport mechanisms.

The role of gender on academic performance in STEM-related disciplines: Data from a tertiary institution.

PubMed

John, Temitope M; Badejo, Joke A; Popoola, Segun I; Omole, David O; Odukoya, Jonathan A; Ajayi, Priscilla O; Aboyade, Mary; Atayero, Aderemi A

2018-06-01

This data article presents data of academic performances of undergraduate students in Science, Technology, Engineering and Mathematics (STEM) disciplines in Covenant University, Nigeria. The data shows academic performances of Male and Female students who graduated from 2010 to 2014. The total population of samples in the observation is 3046 undergraduates mined from Biochemistry (BCH), Building technology (BLD), Computer Engineering (CEN), Chemical Engineering (CHE), Industrial Chemistry (CHM), Computer Science (CIS), Civil Engineering (CVE), Electrical and Electronics Engineering (EEE), Information and Communication Engineering (ICE), Mathematics (MAT), Microbiology (MCB), Mechanical Engineering (MCE), Management and Information System (MIS), Petroleum Engineering (PET), Industrial Physics-Electronics and IT Applications (PHYE), Industrial Physics-Applied Geophysics (PHYG) and Industrial Physics-Renewable Energy (PHYR). The detailed dataset is made available in form of a Microsoft Excel spreadsheet in the supplementary material of this article.

Opto-mechanical subsystem of a 10 micrometer wavelength receiver terminal. Waveguide laser local oscillator. Servo system

NASA Technical Reports Server (NTRS)

1975-01-01

An engineering model opto-mechanical subsystem for a 10.6-micrometer laser heterodyne receiver is developed, and a CO2 waveguide local oscillator and servo electronics are provided for the receiver. Design goals are presented for the subsystems and overall package design is described. Thermal and mechanical distortion loading tests were performed and the results are included.

Research in nonlinear structural and solid mechanics

NASA Technical Reports Server (NTRS)

Mccomb, H. G., Jr. (Compiler); Noor, A. K. (Compiler)

1981-01-01

Recent and projected advances in applied mechanics, numerical analysis, computer hardware and engineering software, and their impact on modeling and solution techniques in nonlinear structural and solid mechanics are discussed. The fields covered are rapidly changing and are strongly impacted by current and projected advances in computer hardware. To foster effective development of the technology perceptions on computing systems and nonlinear analysis software systems are presented.

Activities report of the Department of Engineering

NASA Astrophysics Data System (ADS)

Acoustics, aerodynamics, fluid mechanics, design, electrical, materials science, mechanical, control, robotics, soil mechanics, structural engineering, thermodynamics, and turbomachine engineering research are described.

The Educational Needs of Graduate Mechanical Engineers in New Zealand.

ERIC Educational Resources Information Center

Deans, J.

1999-01-01

Surveys graduate and undergraduate mechanical engineering students at the University of Auckland. Shows that the dominant work activities of New Zealand mechanical engineers include design and consultancy and that graduate engineers rapidly migrate into management. (Author/CCM)

Homologous structure-function relationships between native fibrocartilage and tissue engineered from MSC-seeded nanofibrous scaffolds.

PubMed

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

2011-01-01

Understanding the interplay of composition, organization and mechanical function in load-bearing tissues is a prerequisite in the successful engineering of tissues to replace diseased ones. Mesenchymal stem cells (MSCs) seeded on electrospun scaffolds have been successfully used to generate organized tissues that mimic fibrocartilages such as the knee meniscus and the annulus fibrosus of the intervertebral disc. While matrix deposition has been observed in parallel with improved mechanical properties, how composition, organization, and mechanical function are related is not known. Moreover, how this relationship compares to that of native fibrocartilage is unclear. Therefore, in the present work, functional fibrocartilage constructs were formed from MSC-seeded nanofibrous scaffolds, and the roles of collagen and glycosaminoglycan (GAG) in compressive and tensile properties were determined. MSCs deposited abundant collagen and GAG over 120 days of culture, and these extracellular molecules were organized in such a way that they performed similar mechanical functions to their native roles: collagen dominated the tensile response while GAG was important for compressive properties. GAG removal resulted in significant stiffening in tension. A similar stiffening response was observed when GAG was removed from native inner annulus fibrosus, suggesting an interaction between collagen fibers and their surrounding extrafibrillar matrix that is shared by both engineered and native fibrocartilages. These findings strongly support the use of electrospun scaffolds and MSCs for fibrocartilage tissue engineering, and provide insight on the structure-function relations of both engineered and native biomaterials. Copyright © 2010 Elsevier Ltd. All rights reserved.

Magnetic targeting of mechanosensors in bone cells for tissue engineering applications.

PubMed

Hughes, Steven; Dobson, Jon; El Haj, Alicia J

2007-01-01

Mechanical signalling plays a pivotal role in maintaining bone cell function and remodelling of the skeleton. Our previous work has highlighted the potential role of mechano-induction in tissue engineering applications. In particular, we have highlighted the potential for using magnetic particle techniques for tissue engineering applications. Previous studies have shown that manipulation of integrin attached magnetic particles leads to changes in intracellular calcium signalling within osteoblasts. However, due to the phenomenon of particle internalisation, previous studies have typically focused on short-term stimulation experiments performed within 1-2 h of particle attachment. For tissue engineering applications, bone tissue growth occurs over a period of 3-5 weeks. To date, no study has investigated the cellular responses elicited from osteoblasts over time following stimulation with internalised magnetic particles. Here, we demonstrate the long-term biocompatibility of 4.5 microm RGD-coated particles with osteoblasts up to 21 days in culture, and detail a time course of responses elicited from osteoblasts following mechanical stimulation with integrin attached magnetic particles (<2h post attachment) and internalised particles (>48h post attachment). Mechanical manipulation of both integrin attached and internalised particles were found to induce intracellular calcium signalling. It is concluded that magnetic particles offer a tool for applying controlled mechanical forces to osteoblasts, and can be used to stimulate intracellular calcium signalling over prolonged periods of time. Magnetic particle technology presents a potentially valuable tool for tissue engineering which permits the delivery of highly localised mechano-inductive forces directly to cells.

HOMOLOGOUS STRUCTURE-FUNCTION RELATIONSHIPS BETWEEN NATIVE FIBROCARTILAGE AND TISSUE ENGINEERED FROM MSC-SEEDED NANOFIBROUS SCAFFOLDS

PubMed Central

Nerurkar, Nandan L.; Han, Woojin; Mauck, Robert L.; Elliott, Dawn M.

2010-01-01

Understanding the interplay of composition, organization and mechanical function in load-bearing tissues is a prerequisite in the successful engineering of replacement tissues for diseased ones. Mesenchymal stem cells (MSCs) seeded on electrospun scaffolds have been successfully used to generate organized tissues that mimic fibrocartilages such as the knee meniscus and the annulus fibrosus of the intervertebral disc. While matrix deposition has been observed in parallel with improved mechanical properties, how composition, organization, and mechanical function are related is not known. Moreover, how this relationship compares to that of native fibrocartilage is unclear. Therefore, in the present work, functional fibrocartilage constructs were formed from MSC-seeded nanofibrous scaffolds, and the roles of collagen and glycosaminoglycan (GAG) in compressive and tensile properties were determined. MSCs deposited abundant collagen and GAG over 120 days of culture, and these extracellular molecules were organized in such a way that they performed similar mechanical functions to their native roles: collagen dominated the tensile response while GAG was important for compressive properties. GAG removal resulted in significant stiffening in tension. A similar stiffening response was observed when GAG was removed from native inner annulus fibrosus, suggesting an interaction between collagen fibers and their surrounding extrafibrillar matrix that is shared by both engineered and native fibrocartilages. These findings strongly support the use of electrospun scaffolds and MSCs for fibrocartilage tissue engineering, and provide insight on the structure-function relations of both engineered and native biomaterials. PMID:20880577

A Blended Learning Approach to Teach Fluid Mechanics in Engineering

ERIC Educational Resources Information Center

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…

Evaluating the Learning Process of Mechanical CAD Students

ERIC Educational Resources Information Center

Hamade, R. F.; Artail, H. A.; Jaber, M. Y.

2007-01-01

There is little theoretical or experimental research on how beginner-level trainees learn CAD skills in formal training sessions. This work presents findings on how trainees develop their skills in utilizing a solid mechanical CAD tool (Pro/Engineer version 2000i[squared] and later version Wildfire). Exercises at the beginner and intermediate…

Integrating Technical Communication in the Mechanical Engineering Curriculum

NASA Astrophysics Data System (ADS)

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.

Present Circumstances and its Effect of Participation in NHK Robocon/RoboCup Competition for Engineering Education in College of Technology

NASA Astrophysics Data System (ADS)

Sugiura, Touko; Ito, Kazuaki; Watanabe, Masato

The engineering education through making robots which needs various techniques such as construction of mechanism and electric circuit design are very useful for training of the students' creativity and developing the students' personality. Toyota National College of Technology has participate in NHK Robocon competition for sixteen years and Robocup competition for four years as a part of engineering education getting spectacular results in those competitions. This paper discusses the present circumstances and its effect of participation in Robocon/RoboCup competition for the engineering education, based on the students' questionnaire survey. It is described to participate in NHK Robocon competition is very important for enhancing the students' knowledge and experience. Furthermore, the participation in Robocup competition brings better results for student' personality development as compared with participation in only Robocon competition.

Session 6: Dynamic Modeling and Systems Analysis

NASA Technical Reports Server (NTRS)

Csank, Jeffrey; Chapman, Jeffryes; May, Ryan

2013-01-01

These presentations cover some of the ongoing work in dynamic modeling and dynamic systems analysis. The first presentation discusses dynamic systems analysis and how to integrate dynamic performance information into the systems analysis. The ability to evaluate the dynamic performance of an engine design may allow tradeoffs between the dynamic performance and operability of a design resulting in a more efficient engine design. The second presentation discusses the Toolbox for Modeling and Analysis of Thermodynamic Systems (T-MATS). T-MATS is a Simulation system with a library containing the basic building blocks that can be used to create dynamic Thermodynamic Systems. Some of the key features include Turbo machinery components, such as turbines, compressors, etc., and basic control system blocks. T-MAT is written in the Matlab-Simulink environment and is open source software. The third presentation focuses on getting additional performance from the engine by allowing the limit regulators only to be active when a limit is danger of being violated. Typical aircraft engine control architecture is based on MINMAX scheme, which is designed to keep engine operating within prescribed mechanical/operational safety limits. Using a conditionally active min-max limit regulator scheme, additional performance can be gained by disabling non-relevant limit regulators

Shale Failure Mechanics and Intervention Measures in Underground Coal Mines: Results From 50 Years of Ground Control Safety Research

PubMed Central

2015-01-01

Ground control research in underground coal mines has been ongoing for over 50 years. One of the most problematic issues in underground coal mines is roof failures associated with weak shale. This paper will present a historical narrative on the research the National Institute for Occupational Safety and Health has conducted in relation to rock mechanics and shale. This paper begins by first discussing how shale is classified in relation to coal mining. Characterizing and planning for weak roof sequences is an important step in developing an engineering solution to prevent roof failures. Next, the failure mechanics associated with the weak characteristics of shale will be discussed. Understanding these failure mechanics also aids in applying the correct engineering solutions. The various solutions that have been implemented in the underground coal mining industry to control the different modes of failure will be summarized. Finally, a discussion on current and future research relating to rock mechanics and shale is presented. The overall goal of the paper is to share the collective ground control experience of controlling roof structures dominated by shale rock in underground coal mining. PMID:26549926

Shale Failure Mechanics and Intervention Measures in Underground Coal Mines: Results From 50 Years of Ground Control Safety Research.

PubMed

Murphy, M M

2016-02-01

Ground control research in underground coal mines has been ongoing for over 50 years. One of the most problematic issues in underground coal mines is roof failures associated with weak shale. This paper will present a historical narrative on the research the National Institute for Occupational Safety and Health has conducted in relation to rock mechanics and shale. This paper begins by first discussing how shale is classified in relation to coal mining. Characterizing and planning for weak roof sequences is an important step in developing an engineering solution to prevent roof failures. Next, the failure mechanics associated with the weak characteristics of shale will be discussed. Understanding these failure mechanics also aids in applying the correct engineering solutions. The various solutions that have been implemented in the underground coal mining industry to control the different modes of failure will be summarized. Finally, a discussion on current and future research relating to rock mechanics and shale is presented. The overall goal of the paper is to share the collective ground control experience of controlling roof structures dominated by shale rock in underground coal mining.

Shale Failure Mechanics and Intervention Measures in Underground Coal Mines: Results From 50 Years of Ground Control Safety Research

NASA Astrophysics Data System (ADS)

Murphy, M. M.

2016-02-01

Ground control research in underground coal mines has been ongoing for over 50 years. One of the most problematic issues in underground coal mines is roof failures associated with weak shale. This paper will present a historical narrative on the research the National Institute for Occupational Safety and Health has conducted in relation to rock mechanics and shale. This paper begins by first discussing how shale is classified in relation to coal mining. Characterizing and planning for weak roof sequences is an important step in developing an engineering solution to prevent roof failures. Next, the failure mechanics associated with the weak characteristics of shale will be discussed. Understanding these failure mechanics also aids in applying the correct engineering solutions. The various solutions that have been implemented in the underground coal mining industry to control the different modes of failure will be summarized. Finally, a discussion on current and future research relating to rock mechanics and shale is presented. The overall goal of the paper is to share the collective ground control experience of controlling roof structures dominated by shale rock in underground coal mining.

Modular Engine Noise Component Prediction System (MCP) Technical Description and Assessment Document

NASA Technical Reports Server (NTRS)

Herkes, William H.; Reed, David H.

2005-01-01

This report describes an empirical prediction procedure for turbofan engine noise. The procedure generates predicted noise levels for several noise components, including inlet- and aft-radiated fan noise, and jet-mixing noise. This report discusses the noise source mechanisms, the development of the prediction procedures, and the assessment of the accuracy of these predictions. Finally, some recommendations for future work are presented.

Physics and Process Modeling (PPM) and Other Propulsion R and T. Volume 1; Materials Processing, Characterization, and Modeling; Lifting Models

NASA Technical Reports Server (NTRS)

1997-01-01

This CP contains the extended abstracts and presentation figures of 36 papers presented at the PPM and Other Propulsion R&T Conference. The focus of the research described in these presentations is on materials and structures technologies that are parts of the various projects within the NASA Aeronautics Propulsion Systems Research and Technology Base Program. These projects include Physics and Process Modeling; Smart, Green Engine; Fast, Quiet Engine; High Temperature Engine Materials Program; and Hybrid Hyperspeed Propulsion. Also presented were research results from the Rotorcraft Systems Program and work supported by the NASA Lewis Director's Discretionary Fund. Authors from NASA Lewis Research Center, industry, and universities conducted research in the following areas: material processing, material characterization, modeling, life, applied life models, design techniques, vibration control, mechanical components, and tribology. Key issues, research accomplishments, and future directions are summarized in this publication.

Noise from turbomachinery.

NASA Technical Reports Server (NTRS)

Feiler, C. E.; Conrad, E. W.

1973-01-01

This paper reviews turbomachinery noise from turbofan engines as typified by fan noise. The mechanisms and theories of fan noise are reviewed and concepts for its reduction, including acoustic suppresion are discussed. Correlations of the overall noise data from several full-scale fans tested at NASA-Lewis Research Center are presented as indicative of the current state-of-the-art. Estimates are presented to show economics versus reduced noise for two quieted experimental engines, one with subsonic and one with supersonic fan tip speed. Finally, some concepts that may have the potential to reduce fan noise are indicated.

Introductory Education for Mechanical Engineering by Exercise in Mechanical Disassembly

NASA Astrophysics Data System (ADS)

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.

Mechatronic system design course for undergraduate programmes

NASA Astrophysics Data System (ADS)

Saleem, A.; Tutunji, T.; Al-Sharif, L.

2011-08-01

Technology advancement and human needs have led to integration among many engineering disciplines. Mechatronics engineering is an integrated discipline that focuses on the design and analysis of complete engineering systems. These systems include mechanical, electrical, computer and control subsystems. In this paper, the importance of teaching mechatronic system design to undergraduate engineering students is emphasised. The paper offers the collaborative experience in preparing and delivering the course material for two universities in Jordan. A detailed description of such a course is provided and a case study is presented. The case study used is a final year project, where students applied a six-stage design procedure that is described in the paper.

Development of a CFRP Engine Thrust Frame for the Next Generation Launchers

NASA Astrophysics Data System (ADS)

Fatemi, Javad; van der Bas, Finn; Cruijssen, Henk

2012-07-01

This paper addresses the activities related to the development of technologies for a composite Engine Thrust Frame (ETF) for the next generation launchers. In particular, the design and analyses of a full Carbon Fibre Reinforced Plastic (CFRP) engine thrust frame are presented in more detail. The ETF concept is composed of three main parts, i.e. an aluminium top-ring which connects the ETF to the upper-stage tank, a CFRP cone, and a CFRP cone-cap which connects the Vinci engine to the ETF. The main challenging requirements for development of a CFRP ETF are recalled. The ETF concept and its mechanical performances are assessed.

Three-grid accelerator system for an ion propulsion engine

NASA Technical Reports Server (NTRS)

Brophy, John R. (Inventor)

1994-01-01

An apparatus is presented for an ion engine comprising a three-grid accelerator system with the decelerator grid biased negative of the beam plasma. This arrangement substantially reduces the charge-exchange ion current reaching the accelerator grid at high tank pressures, which minimizes erosion of the accelerator grid due to charge exchange ion sputtering, known to be the major accelerator grid wear mechanism. An improved method for life testing ion engines is also provided using the disclosed apparatus. In addition, the invention can also be applied in materials processing.

Development of structural ceramic components for automobile applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kawamoto, H.

1995-12-01

Development efforts have been made in automobile technologies on heat engines to improve the power performance, the fuel economy, and so on. It is well recognized that ceramic applications are keys to succeed in such advanced heat engines, because of their good mechanical and thermal properties. This paper discusses present automobile applications of structural ceramic components and the expectations in automobile uses. The strength and reliability of mass-produced components for the engines are described with the manufacturing processes. The future R&D directions are recommended for structural ceramics.

The 1975 NASA/ASEE summer faculty fellowship research program. [research in the areas of aerospace engineering, aerospace systems, and information systems

NASA Technical Reports Server (NTRS)

1975-01-01

A research program was conducted to further the professional knowledge of qualified engineering and science faculty members, to stimulate an exchange of ideas between participants and NASA engineers and scientists, and to enrich the research activities of the participants' institutions. Abstracts of reports submitted at the end of the program are presented. Topics investigated include multispectral photography, logic circuits, gravitation theories, information systems, fracture mechanics, holographic interferometry, surface acoustic wave technology, ion beams in the upper atmosphere, and hybrid microcircuits.

Compendium of Abstracts on Statistical Applications in Geotechnical Engineering.

DTIC Science & Technology

1983-09-01

research in the application of probabilistic and statistical methods to soil mechanics, rock mechanics, and engineering geology problems have grown markedly...probability, statistics, soil mechanics, rock mechanics, and engineering geology. 2. The purpose of this report is to make available to the U. S...Deformation Dynamic Response Analysis Seepage, Soil Permeability and Piping Earthquake Engineering, Seismology, Settlement and Heave Seismic Risk Analysis

Teaching Continuum Mechanics in a Mechanical Engineering Program

ERIC Educational Resources Information Center

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…

Dynamic behavior of the mechanical systems from the structure of a hybrid automobile

NASA Astrophysics Data System (ADS)

Dinel, Popa; Irina, Tudor; Nicolae-Doru, Stănescu

2017-10-01

In introduction are presented solutions of planetary mechanisms that can be used in the construction of the hybrid automobiles where the thermal and electrical sources must be coupled. The systems have in their composition a planetary mechanism with two degrees of mobility at which are coupled a thermal engine, two revertible electrical machines, a gear transmission with four gears and a differential mechanism which transmits the motion at the driving wheels. For the study of the dynamical behavior, with numerical results, one designs such mechanisms, models the elements with solids in AutoCAD, and obtains the mechanical properties of the elements. Further on, we present and solve the equations of motion of a hybrid automotive for which one knows the dynamical parameters.

Tissue engineering therapy for cardiovascular disease.

PubMed

Nugent, Helen M; Edelman, Elazer R

2003-05-30

The present treatments for the loss or failure of cardiovascular function include organ transplantation, surgical reconstruction, mechanical or synthetic devices, or the administration of metabolic products. Although routinely used, these treatments are not without constraints and complications. The emerging and interdisciplinary field of tissue engineering has evolved to provide solutions to tissue creation and repair. Tissue engineering applies the principles of engineering, material science, and biology toward the development of biological substitutes that restore, maintain, or improve tissue function. Progress has been made in engineering the various components of the cardiovascular system, including blood vessels, heart valves, and cardiac muscle. Many pivotal studies have been performed in recent years that may support the move toward the widespread application of tissue-engineered therapy for cardiovascular diseases. The studies discussed include endothelial cell seeding of vascular grafts, tissue-engineered vascular conduits, generation of heart valve leaflets, cardiomyoplasty, genetic manipulation, and in vitro conditions for optimizing tissue-engineered cardiovascular constructs.

Coupling of PZT Thin Films with Bimetallic Strip Heat Engines for Thermal Energy Harvesting.

PubMed

Boughaleb, Jihane; Arnaud, Arthur; Guiffard, Benoit; Guyomar, Daniel; Seveno, Raynald; Monfray, Stéphane; Skotnicki, Thomas; Cottinet, Pierre-Jean

2018-06-06

A thermal energy harvester based on a double transduction mechanism and which converts thermal energy into electrical energy by means of piezoelectric membranes and bimetals, has previously been developed and widely presented in the literature In such a device, the thermo-mechanical conversion is ensured by a bimetal whereas the electro-mechanical conversion is generated by a piezoelectric ceramic. However, it has been shown that only 19% of the mechanical energy delivered by the bimetal during its snap is converted into electrical energy. To extract more energy from the bimetallic strip and to increase the transduction efficiency, a new way to couple piezoelectric materials with bimetals has thus been explored through direct deposition of piezoelectric layers on bimetals. This paper consequently presents an alternative way to harvest heat, based on piezoelectric bimetallic strip heat engines and presents a proof of concept of such a system. In this light, different PZT (Lead zirconate titanate) thin films were synthesized directly on aluminium foils and were attached to the bimetals using conductive epoxy. The fabrication process of each sample is presented herein as well as the experimental tests carried out on the devices. Throughout this study, different thicknesses of the piezoelectric layers and substrates were tested to determine the most powerful configuration. Finally, the study also gives some guidelines for future improvements of piezoelectric bimetals.

Air Force Center of Excellence on Bio-nano-enabled Inorganic/Organic Nanostructures and Improved Cognition (BIONIC)

DTIC Science & Technology

2015-01-09

IRG #3)  Mostafa A. El-Sayed, School of Chemistry & Biochemistry (IRG #2)  Andrei Fedorov, School of Mechanical Engineering (IRG #2)  Michael A...Engineering, U.S. Citizen)  *David Anderson (Ph.D. student, School of Mechanical Engineering, U.S. Citizen)  Luke A. Beardslee (Ph.D. student, School...Songkil Kim (PhD student, School of Mechanical Engineering)  Philip Kwon (Ph.D. student, School of Mechanical Engineering, U.S. Citizen)  Erin Lightman

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

NASA Astrophysics Data System (ADS)

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.

Creep, Fatigue and Fracture Behavior of Environmental Barrier Coating and SiC-SiC Ceramic Matrix Composite Systems: The Role of Environment Effects

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Ghosn, Louis J.

2015-01-01

Advanced environmental barrier coating (EBC) systems for low emission SiCSiC CMC combustors and turbine airfoils have been developed to meet next generation engine emission and performance goals. This presentation will highlight the developments of NASAs current EBC system technologies for SiC-SiC ceramic matrix composite combustors and turbine airfoils, their performance evaluation and modeling progress towards improving the engine SiCSiC component temperature capability and long-term durability. Our emphasis has also been placed on the fundamental aspects of the EBC-CMC creep and fatigue behaviors, and their interactions with turbine engine oxidizing and moisture environments. The EBC-CMC environmental degradation and failure modes, under various simulated engine testing environments, in particular involving high heat flux, high pressure, high velocity combustion conditions, will be discussed aiming at quantifying the protective coating functions, performance and durability, and in conjunction with damage mechanics and fracture mechanics approaches.

Experimental study on mechanism and shape characteristics of suspended flexible dam

NASA Astrophysics Data System (ADS)

Wang, Jian-zhong; Fan, Hong-xia; Zhu, Li-jun

2014-12-01

Hydraulic structures such as groin, longitudinal dike and seawall are common in water conservancy and water transportation engineering projects at home and abroad, which have long been dominated by solid mass structural form. With brush and stone as building materials, this kind of structure has an obvious engineering effect. However, it not only requires huge capital investments, but also has negative impacts on the ecological environment. The suspended flexible dam is an innovative engineering measure, and few theoretical and experimental researches of this type dam can be found at present. This paper studies the mechanism and shape characteristics of this dam and obtains the dynamic equilibrium equation of flexible dam, the float buoyancy expression, and the condition for transformation among three forms of the underwater shape of the dam. The results are valuable in engineering application and can be used as the reference for the future work due to the distinctive design philosophy, the small negative effects on environment and the consistency for sustainable development.

Impact of air conditioning system operation on increasing gases emissions from automobile

NASA Astrophysics Data System (ADS)

Burciu, S. M.; Coman, G.

2016-08-01

The paper presents a study concerning the influence of air conditioning system operation on the increase of gases emissions from cars. The study focuses on urban operating regimes of the automobile, regimes when the engines have low loads or are operating at idling. Are presented graphically the variations of pollution emissions (CO, CO2, HC) depending of engine speed and the load on air conditioning system. Additionally are presented, injection duration, throttle position, the mechanical power required by the compressor of air conditioning system and the refrigerant pressure variation on the discharge path, according to the stage of charging of the air conditioning system.

State-of-the-Art Review of 3D Bioprinting for Cardiovascular Tissue Engineering.

PubMed

Duan, Bin

2017-01-01

3D bioprinting is a group of rapidly growing techniques that allows building engineered tissue constructs with complex and hierarchical structures, mechanical and biological heterogeneity. It enables implementation of various bioinks through different printing mechanisms and precise deposition of cell and/or biomolecule laden biomaterials in predefined locations. This review briefly summarizes applicable bioink materials and various bioprinting techniques, and presents the recent advances in bioprinting of cardiovascular tissues, with focusing on vascularized constructs, myocardium and heart valve conduits. Current challenges and further perspectives are also discussed to help guide the bioink and bioprinter development, improve bioprinting strategies and direct future organ bioprinting and translational applications.

Present State of the Art of Composite Fabric Forming: Geometrical and Mechanical Approaches

PubMed Central

Cherouat, Abel; Borouchaki, Houman

2009-01-01

Continuous fibre reinforced composites are now firmly established engineering materials for the manufacture of components in the automotive and aerospace industries. In this respect, composite fabrics provide flexibility in the design manufacture. The ability to define the ply shapes and material orientation has allowed engineers to optimize the composite properties of the parts. The formulation of new numerical models for the simulation of the composite forming processes must allow for reduction in the delay in manufacturing and an optimization of costs in an integrated design approach. We propose two approaches to simulate the deformation of woven fabrics: geometrical and mechanical approaches.

Procedure for implementation of temperature-dependent mechanical property capability in the Engineering Analysis Language (EAL) system

NASA Technical Reports Server (NTRS)

Glass, David E.; Robinson, James C.

1990-01-01

A procedure is presented to allow the use of temperature dependent mechanical properties in the Engineering Analysis Language (EAL) System for solid structural elements. This is accomplished by including a modular runstream in the main EAL runstream. The procedure is applicable for models with multiple materials and with anisotropic properties, and can easily be incorporated into an existing EAL runstream. The procedure (which is applicable for EAL elastic solid elements) is described in detail, followed by a description of the validation of the routine. A listing of the EAL runstream used to validate the procedure is included in the Appendix.

Reusable rocket engine turbopump health monitoring system, part 3

NASA Technical Reports Server (NTRS)

Perry, John G.

1989-01-01

Degradation mechanisms and sensor identification/selection resulted in a list of degradation modes and a list of sensors that are utilized in the diagnosis of these degradation modes. The sensor list is divided into primary and secondary indicators of the corresponding degradation modes. The signal conditioning requirements are discussed, describing the methods of producing the Space Shuttle Main Engine (SSME) post-hot-fire test data to be utilized by the Health Monitoring System. Development of the diagnostic logic and algorithms is also presented. The knowledge engineering approach, as utilized, includes the knowledge acquisition effort, characterization of the expert's problem solving strategy, conceptually defining the form of the applicable knowledge base, and rule base, and identifying an appropriate inferencing mechanism for the problem domain. The resulting logic flow graphs detail the diagnosis/prognosis procedure as followed by the experts. The nature and content of required support data and databases is also presented. The distinction between deep and shallow types of knowledge is identified. Computer coding of the Health Monitoring System is shown to follow the logical inferencing of the logic flow graphs/algorithms.

Analytical techniques: A compilation

NASA Technical Reports Server (NTRS)

1975-01-01

A compilation, containing articles on a number of analytical techniques for quality control engineers and laboratory workers, is presented. Data cover techniques for testing electronic, mechanical, and optical systems, nondestructive testing techniques, and gas analysis techniques.

Mechanical Engineering Technology Curriculum.

ERIC Educational Resources Information Center

Georgia State Univ., Atlanta. Dept. of Vocational and Career Development.

This guide offers information and procedures necessary to train mechanical engineering technicians. Discussed first are the rationale and objectives of the curriculum. The occupational field of mechanical engineering technology is described. Next, a curriculum model is set forth that contains information on the standard mechanical engineering…

Basic mechanics of laminated composite plates

NASA Technical Reports Server (NTRS)

Nettles, Alan T.

1994-01-01

The mechanics of laminated composite materials is presented in a clear manner with only essential derivations included. The constitutive equations in all of their forms are developed and then summarized in a separate section. The effects of hygrothermal effects are included. The prediction of the engineering constants for a laminate are derived. Strength of laminated composites is not covered.

Molecular Engineering for Mechanically Resilient and Stretchable Electronic Polymers and Composites

DTIC Science & Technology

2016-06-08

AFRL-AFOSR-VA-TR-2016-0231 Molecular Engineering for Mechanically Resilient and Stretchable Electronic Polymers and Composites Darren Lipomi...04-2013 to 31-03-2016 4. TITLE AND SUBTITLE Molecular Engineering for Mechanically Resilient and Stretchable Electronic Polymers and Composites 5a... Engineering for Mechanically Resilient and Stretchable Electronic Polymers and Composites PI: Prof. Darren J. Lipomi 9500 Gilman Dr., Mail Code #0448

The 1990-1991 project summaries

NASA Technical Reports Server (NTRS)

1991-01-01

Georgia Tech's School of Textile & Fiber Engineering and School of Mechanical Engineering participated in four cooperative design efforts this year. One group designed a thermal shield for a lunar telescope. The second group designed a selenotextile habitat shielding structure. The third group designed a pneumatically assisted elbow joint for the NASA zero-prebreathe suit (ZPS). The final group designed an electromechanical system to power an astronaut's finger joints. Summaries of these projects are presented.

The 1990-1991 project summaries

NASA Astrophysics Data System (ADS)

Georgia Tech's School of Textile & Fiber Engineering and School of Mechanical Engineering participated in four cooperative design efforts this year. One group designed a thermal shield for a lunar telescope. The second group designed a selenotextile habitat shielding structure. The third group designed a pneumatically assisted elbow joint for the NASA zero-prebreathe suit (ZPS). The final group designed an electromechanical system to power an astronaut's finger joints. Summaries of these projects are presented.

Development of Diesel Engine Diagnostics for U.S. Coast Guard Cutters.

DTIC Science & Technology

1981-07-01

even though this type of transducer is sensitive to both acoustic noise and mechanical vibration. These "noise" signals are ordinarily of much higher...Unfortunately, this maintenance work was not scheduled for the immediate future, but the E.O. did agree to make exhaust pyrometer readings for the...pressure pulsations normally present in the engine crankcase. However, the very sensitive pressure transducer apparently registered the acoustical

Blood Pump Development Using Rocket Engine Flow Simulation Technology

NASA Technical Reports Server (NTRS)

Kiris, Cetin C.; Kwak, Dochan

2002-01-01

This viewgraph presentation provides information on the transfer of rocket engine flow simulation technology to work involving the development of blood pumps. Details are offered regarding the design and requirements of mechanical heart assist devices, or VADs (ventricular assist device). There are various computational fluid dynamics issues involved in the visualization of flow in such devices, and these are highlighted and compared to those of rocket turbopumps.

A Transversely Isotropic Thermo-mechanical Framework for Oil Shale

NASA Astrophysics Data System (ADS)

Semnani, S. J.; White, J. A.; Borja, R. I.

2014-12-01

The present study provides a thermo-mechanical framework for modeling the temperature dependent behavior of oil shale. As a result of heating, oil shale undergoes phase transformations, during which organic matter is converted to petroleum products, e.g. light oil, heavy oil, bitumen, and coke. The change in the constituents and microstructure of shale at high temperatures dramatically alters its mechanical behavior e.g. plastic deformations and strength, as demonstrated by triaxial tests conducted at multiple temperatures [1,2]. Accordingly, the present model formulates the effects of changes in the chemical constituents due to thermal loading. It is well known that due to the layered structure of shale its mechanical properties in the direction parallel to the bedding planes is significantly different from its properties in the perpendicular direction. Although isotropic models simplify the modeling process, they fail to accurately describe the mechanical behavior of these rocks. Therefore, many researchers have studied the anisotropic behavior of rocks, including shale [3]. The current study presents a framework to incorporate the effects of transverse isotropy within a thermo-mechanical formulation. The proposed constitutive model can be readily applied to existing finite element codes to predict the behavior of oil shale in applications such as in-situ retorting process and stability assessment in petroleum reservoirs. [1] Masri, M. et al."Experimental Study of the Thermomechanical Behavior of the Petroleum Reservoir." SPE Eastern Regional/AAPG Eastern Section Joint Meeting. Society of Petroleum Engineers, 2008. [2] Xu, B. et al. "Thermal impact on shale deformation/failure behaviors---laboratory studies." 45th US Rock Mechanics/Geomechanics Symposium. American Rock Mechanics Association, 2011. [3] Crook, AJL et al. "Development of an orthotropic 3D elastoplastic material model for shale." SPE/ISRM Rock Mechanics Conference. Society of Petroleum Engineers, 2002.

Evaluation of Separation Mechanism Design for the Orion/Ares Launch Vehicle

NASA Technical Reports Server (NTRS)

Konno, Kevin E.; Catalano, Daniel A.; Krivanek, Thomas M.

2008-01-01

As a part of the preliminary design work being performed for the Orion vehicle, the Orion to Spacecraft Adaptor (SA) separation mechanism was analyzed and sized, with findings presented here. Sizing is based on worst case abort condition as a result of an anomaly driving the launch vehicle engine thrust vector control hard-over causing a severe vehicle pitch over. This worst case scenario occurs just before Upper Stage Main Engine Cut-Off (MECO) when the vehicle is the lightest and the damping effect due to propellant slosh has been reduced to a minimum. To address this scenario and others, two modeling approaches were invoked. The first approach was a detailed 2-D (Simulink) model to quickly assess the Service Module Engine nozzle to SA clearance for a given separation mechanism. The second approach involved the generation of an Automatic Dynamic Analysis of Mechanical Systems (ADAMS) model to assess secondary effects due to mass centers of gravity that were slightly off the vehicle centerline. It also captured any interference between the Solar Arrays and the Spacecraft Adapter. A comparison of modeling results and accuracy are discussed. Most notably, incorporating a larger SA flange diameter allowed for a natural separation of the Orion and its engine nozzle even at relatively large pitch rates minimizing the kickoff force. Advantages and disadvantages of the 2-D model vs. a full 3-D (ADAMS) model are discussed as well.

Evaluation of Separation Mechanism Design for the Orion/Ares Launch Vehicle

NASA Technical Reports Server (NTRS)

Konno, Kevin E.; Catalano, Daniel A.; Krivanek, Thomas M.

2008-01-01

As a part of the preliminary design work being performed for the Orion vehicle, the Orion to Spacecraft Adaptor (SA) separation mechanism was analyzed and sized, with findings presented here. Sizing is based on worst case abort condition as a result of an anomaly driving the launch vehicle engine thrust vector control hard-over causing a severe vehicle pitch over. This worst-case scenario occurs just before Upper Stage Main Engine Cut-Off when the vehicle is the lightest and the damping effect due to propellant slosh has been reduced to a minimum. To address this scenario and others, two modeling approaches were invoked. The first approach was a detailed Simulink model to quickly assess the Service Module Engine nozzle to SA clearance for a given separation mechanism. The second approach involved the generation of an Automatic Dynamic Analysis of Mechanical Systems (ADAMS) model to assess secondary effects due to mass centers of gravity that were slightly off the vehicle centerline. It also captured any interference between the Solar Arrays and the Spacecraft Adapter. A comparison of modeling results and accuracy are discussed. Most notably, incorporating a larger SA flange diameter allowed for a natural separation of the Orion and its engine nozzle even at relatively large pitch rates minimizing the kickoff force. Advantages and disadvantages of the Simulink model vs. a full geometric ADAMS model are discussed as well.

Evaluation of Separation Mechanism Design for the Orion/Ares Launch Vehicle

NASA Technical Reports Server (NTRS)

Konno, Kevin E.; Catalano, Daniel A.; Krivanek, Thomas M.

2008-01-01

As a part of the preliminary design work being performed for the Orion vehicle, the Orion to Spacecraft Adaptor (SA) separation mechanism was analyzed and sized, with findings presented here. Sizing is based on worst case abort condition as a result of an anomaly driving the launch vehicle engine thrust vector control hard-over causing a severe vehicle pitch over. This worst case scenario occurs just before Upper Stage Main Engine Cut-Off (MECO) when the vehicle is the lightest and the damping effect due to propellant slosh has been reduced to a minimum. To address this scenario and others, two modeling approaches were invoked. The first approach was a detailed Simulink model to quickly assess the Service Module Engine nozzle to SA clearance for a given separation mechanism. The second approach involved the generation of an Automatic Dynamic Analysis of Mechanical Systems (ADAMS) model to assess secondary effects due to mass centers of gravity that were slightly off the vehicle centerline. It also captured any interference between the Solar Arrays and the Spacecraft Adapter. A comparison of modeling results and accuracy are discussed. Most notably, incorporating a larger SA flange diameter allowed for a natural separation of the Orion and it's engine nozzle even at relatively large pitch rates minimizing the kickoff force. Advantages and disadvantages of the Simulink model vs. a full geometric ADAMS model are discussed as well.

An elastic-plastic contact model for line contact structures

NASA Astrophysics Data System (ADS)

Zhu, Haibin; Zhao, Yingtao; He, Zhifeng; Zhang, Ruinan; Ma, Shaopeng

2018-06-01

Although numerical simulation tools are now very powerful, the development of analytical models is very important for the prediction of the mechanical behaviour of line contact structures for deeply understanding contact problems and engineering applications. For the line contact structures widely used in the engineering field, few analytical models are available for predicting the mechanical behaviour when the structures deform plastically, as the classic Hertz's theory would be invalid. Thus, the present study proposed an elastic-plastic model for line contact structures based on the understanding of the yield mechanism. A mathematical expression describing the global relationship between load history and contact width evolution of line contact structures was obtained. The proposed model was verified through an actual line contact test and a corresponding numerical simulation. The results confirmed that this model can be used to accurately predict the elastic-plastic mechanical behaviour of a line contact structure.

PREFACE: International Conference on Applied Sciences (ICAS2014)

NASA Astrophysics Data System (ADS)

Lemle, Ludovic Dan; Jiang, Yiwen

2015-06-01

The International Conference on Applied Sciences (ICAS2014) took place in Hunedoara, Romania from 2-4 October 2014 at the Engineering Faculty of Hunedoara. The conference takes place alternately in Romania and in P.R. China and is organized by "Politehnica" University of Timisoara, Romania, and Military Economics Academy of Wuhan, P.R. China, with the aim to serve as a platform for exchange of information between various areas of applied sciences and to promote the communication between scientists of different nations, countries and continents. The topics of the conference covered a comprehensive spectrum of issues: 1. Economical Sciences 2. Engineering Sciences 3. Fundamental Sciences 4. Medical Sciences The conference gathered qualified researchers whose expertise can be used to develop new engineering knowledge that has the potential for application in economics, defense, medicine, etc. There were nearly 100 registered participants from six countries, and four invited and 56 oral talks were delivered during the two days of the conference. Based on the work presented at the conference, selected papers are included in this volume of IOP Conference Series: Materials Science and Engineering. These papers present new research in the various fields of Materials Engineering, Mechanical Engineering, Computer Engineering, and Mathematical Engineering. It is our great pleasure to present this volume of IOP Conference Series: Materials Science and Engineering to the scientific community to promote further research in these areas. We sincerely hope that the papers published in this volume will contribute to the advancement of knowledge in their respective fields.

Integrating interface slicing into software engineering processes

NASA Technical Reports Server (NTRS)

Beck, Jon

1993-01-01

Interface slicing is a tool which was developed to facilitate software engineering. As previously presented, it was described in terms of its techniques and mechanisms. The integration of interface slicing into specific software engineering activities is considered by discussing a number of potential applications of interface slicing. The applications discussed specifically address the problems, issues, or concerns raised in a previous project. Because a complete interface slicer is still under development, these applications must be phrased in future tenses. Nonetheless, the interface slicing techniques which were presented can be implemented using current compiler and static analysis technology. Whether implemented as a standalone tool or as a module in an integrated development or reverse engineering environment, they require analysis no more complex than that required for current system development environments. By contrast, conventional slicing is a methodology which, while showing much promise and intuitive appeal, has yet to be fully implemented in a production language environment despite 12 years of development.

Reverse engineering development: Crosstalk opportunities between developmental biology and tissue engineering.

PubMed

Marcucio, Ralph S; Qin, Ling; Alsberg, Eben; Boerckel, Joel D

2017-11-01

The fields of developmental biology and tissue engineering have been revolutionized in recent years by technological advancements, expanded understanding, and biomaterials design, leading to the emerging paradigm of "developmental" or "biomimetic" tissue engineering. While developmental biology and tissue engineering have long overlapping histories, the fields have largely diverged in recent years at the same time that crosstalk opportunities for mutual benefit are more salient than ever. In this perspective article, we will use musculoskeletal development and tissue engineering as a platform on which to discuss these emerging crosstalk opportunities and will present our opinions on the bright future of these overlapping spheres of influence. The multicellular programs that control musculoskeletal development are rapidly becoming clarified, represented by shifting paradigms in our understanding of cellular function, identity, and lineage specification during development. Simultaneously, advancements in bioartificial matrices that replicate the biochemical, microstructural, and mechanical properties of developing tissues present new tools and approaches for recapitulating development in tissue engineering. Here, we introduce concepts and experimental approaches in musculoskeletal developmental biology and biomaterials design and discuss applications in tissue engineering as well as opportunities for tissue engineering approaches to inform our understanding of fundamental biology. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2356-2368, 2017. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Redirecting adenovirus tropism by genetic, chemical, and mechanical modification of the adenovirus surface for cancer gene therapy.

PubMed

Yoon, A-Rum; Hong, Jinwoo; Kim, Sung Wan; Yun, Chae-Ok

2016-06-01

Despite remarkable advancements, clinical evaluations of adenovirus (Ad)-mediated cancer gene therapies have highlighted the need for improved delivery and targeting. Genetic modification of Ad capsid proteins has been extensively attempted. Although genetic modification enhances the therapeutic potential of Ad, it is difficult to successfully incorporate extraneous moieties into the capsid and the engineering process is laborious. Recently, chemical modification of the Ad surface with nanomaterials and targeting moieties has been found to enhance Ad internalization into the target by both passive and active mechanisms. Alternatively, external stimulus-mediated targeting can result in selective accumulation of Ad in the tumor and prevent dissemination of Ad into surrounding nontarget tissues. In the present review, we discuss various genetic, chemical, and mechanical engineering strategies for overcoming the challenges that hinder the therapeutic efficacy of Ad-based approaches. Surface modification of Ad by genetic, chemical, or mechanical engineering strategies enables Ad to overcome the shortcomings of conventional Ad and enhances delivery efficiency through distinct and unique mechanisms that unmodified Ad cannot mimic. However, although the therapeutic potential of Ad-mediated gene therapy has been enhanced by various surface modification strategies, each strategy still possesses innate limitations that must be addressed, requiring innovative ideas and designs.

Assessment of Knowledge and Skills Needed in Selected Engineering Technician Fields: Mechanical/Manufacturing/Industrial.

ERIC Educational Resources Information Center

Gourley, Frank A., Jr.

A study identified the essential educational topics and the level of proficiency perceived to be required in these topics for selected two-year engineering technology programs in North Carolina. The four curricula studied were mechanical engineering technology, mechanical drafting and design technology, manufacturing engineering technology, and…

Test Rig for Evaluating Active Turbine Blade Tip Clearance Control Concepts

NASA Technical Reports Server (NTRS)

Lattime, Scott B.; Steinetz, Bruce M.; Robbie, Malcolm G.

2003-01-01

Improved blade tip sealing in the high pressure compressor and high pressure turbine can provide dramatic improvements in specific fuel consumption, time-on-wing, compressor stall margin and engine efficiency as well as increased payload and mission range capabilities of both military and commercial gas turbine engines. The preliminary design of a mechanically actuated active clearance control (ACC) system for turbine blade tip clearance management is presented along with the design of a bench top test rig in which the system is to be evaluated. The ACC system utilizes mechanically actuated seal carrier segments and clearance measurement feedback to provide fast and precise active clearance control throughout engine operation. The purpose of this active clearance control system is to improve upon current case cooling methods. These systems have relatively slow response and do not use clearance measurement, thereby forcing cold build clearances to set the minimum clearances at extreme operating conditions (e.g., takeoff, re-burst) and not allowing cruise clearances to be minimized due to the possibility of throttle transients (e.g., step change in altitude). The active turbine blade tip clearance control system design presented herein will be evaluated to ensure that proper response and positional accuracy is achievable under simulated high-pressure turbine conditions. The test rig will simulate proper seal carrier pressure and temperature loading as well as the magnitudes and rates of blade tip clearance changes of an actual gas turbine engine. The results of these evaluations will be presented in future works.

U.S. rail equipment crashworthiness standards

DOT National Transportation Integrated Search

2001-05-01

This paper was presented at the conference, "What Can We Realistically Expect from Crash Worthiness? Improving Train Design to Withstand Future Accidents," which was held at the Institute of Mechanical Engineers' Headquarters at London, England on Ma...

An Attempt to Improve Students' Presentation Skills via Course of Graduation Research and its Educational Effects

NASA Astrophysics Data System (ADS)

Yamaguchi, Kenji; Ohtuka, Sigeru; Morita, Shinichi; Matsumoto, Itaru; Yakabe, Masaki; Hayamizu, Yasutaka; Ohtuka, Kouichi

The importance of presentation skills rapidly increases in engineering education in Japan. The authors have applied various teaching-method of presentation skills to the course of graduation research for the fifth-grade students of the mechanical engineering program in Yonago National College of Technology. The lectures including teachers' demonstration and basic skills in presentation have resulted in improvement of students' skills. The meeting for announcing the results of graduation research has been opened to the public in cooperation with the Yonago Chamber of Commerce and Industry to give the students incentives to graduation research as well as presentation. The students have mutually evaluated their presentation to get good opportunities for even self-evaluation. This paper discusses the effects and problems of our educational practice.

An investigation of crankshaft oscillations for cylinder health diagnostics

NASA Astrophysics Data System (ADS)

Geveci, Mert; Osburn, Andrew W.; Franchek, Matthew A.

2005-09-01

The vibrational characteristics of an internal combustion engine crankshaft are investigated from a cylinder health diagnostics point of view. Experimental results from a six-cylinder industrial diesel engine are presented to demonstrate the effects of cylinder imbalance on the individual harmonic components of the engine speed signal. A crank-angle domain numerical model of the crankshaft dynamics for a six-cylinder industrial diesel engine is also adopted to establish the effects of continuous low-power production in individual cylinders of a multi-cylinder engine. Outline of a diagnostics algorithm that makes use of the properties of crankshaft vibration behaviour is provided. In particular, crank-angle domain notch filters are employed to extact the harmonic components of engine speed. The outlined method can be implemented for individual cylinder health diagnostics across a family of multi-cylinder engines and can be formulated to handle changes in crankshaft characteristics due to replacement of mechanical components and/or wear.

Energy Efficient Engine: Flight propulsion system final design and analysis

NASA Technical Reports Server (NTRS)

Davis, Donald Y.; Stearns, E. Marshall

1985-01-01

The Energy Efficient Engine (E3) is a NASA program to create fuel saving technology for future transport engines. The Flight Propulsion System (FPS) is the engine designed to achieve E3 goals. Achieving these goals required aerodynamic, mechanical and system technologies advanced beyond that of current production engines. These technologies were successfully demonstrated in component rigs, a core engine and a turbofan ground test engine. The design and benefits of the FPS are presented. All goals for efficiency, environmental considerations, and economic payoff were met. The FPS has, at maximum cruise, 10.67 km (35,000 ft), M0.8, standard day, a 16.9 percent lower installed specific fuel consumption than a CF6-50C. It provides an 8.6 percent reduction in direct operating cost for a short haul domestic transport and a 16.2 percent reduction for an international long distance transport.

78 FR 37721 - Approval of American Society of Mechanical Engineers' Code Cases

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-24

...-0359] RIN 3150-AI72 Approval of American Society of Mechanical Engineers' Code Cases AGENCY: Nuclear... mandatory American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (BPV) Code and... Guide'' series. In a notice of proposed rulemaking, ``Approval of American Society of Mechanical...

Small Engines and Outboard Marine Mechanics Curriculum.

ERIC Educational Resources Information Center

Alaska State Dept. of Education, Juneau. Div. of Adult and Vocational Education.

This competency-based curriculum guide is a handbook for the development of small engine and outboard marine mechanics programs. Based on a survey of Alaskan small engines and marine mechanics employers, it includes all competencies a student should acquire in such a mechanics program. The handbook stresses the importance of understanding the…

Performance deterioration based on existing (historical) data; JT9D jet engine diagnostics program

NASA Technical Reports Server (NTRS)

Sallee, G. P.

1978-01-01

The results of the collection and analysis of historical data pertaining to the deterioration of JT9D engine performance are presented. The results of analyses of prerepair and postrepair engine test stand performance data from a number of airlines to establish the individual as well as average losses in engine performance with respect to service use are included. Analysis of the changes in mechanical condition of parts, obtained by inspection of used gas-path parts of varying age, allowed preliminary assessments of component performance deterioration levels and identification of the causitive factors. These component performance estimates, refined by data from special engine back-to-back testing related to module performance restoration, permitted the development of preliminary models of engine component/module performance deterioration with respect to usage. The preliminary assessment of the causes of module performance deterioration and the trends with usage are explained, along with the role each module plays in overall engine performance deterioration. Preliminary recommendations with respect to operating and maintenance practices which could be adopted to control the level of performance deterioration are presented. The needs for additional component sensitivity testing as well as outstanding issues are discussed.

Notes on Earth Atmospheric Entry for Mars Sample Return Missions

NASA Technical Reports Server (NTRS)

Rivell, Thomas

2006-01-01

The entry of sample return vehicles (SRVs) into the Earth's atmosphere is the subject of this document. The Earth entry environment for vehicles, or capsules, returning from the planet Mars is discussed along with the subjects of dynamics, aerodynamics, and heat transfer. The material presented is intended for engineers and scientists who do not have strong backgrounds in aerodynamics, aerothermodynamics and flight mechanics. The document is not intended to be comprehensive and some important topics are omitted. The topics considered in this document include basic principles of physics (fluid mechanics, dynamics and heat transfer), chemistry and engineering mechanics. These subjects include: a) fluid mechanics (aerodynamics, aerothermodynamics, compressible fluids, shock waves, boundary layers, and flow regimes from subsonic to hypervelocity; b) the Earth s atmosphere and gravity; c) thermal protection system design considerations; d) heat and mass transfer (convection, radiation, and ablation); e) flight mechanics (basic rigid body dynamics and stability); and f) flight- and ground-test requirements; and g) trajectory and flow simulation methods.

A review of acoustic dampers applied to combustion chambers in aerospace industry

NASA Astrophysics Data System (ADS)

Zhao, Dan; Li, X. Y.

2015-04-01

In engine combustion systems such as rockets, aero-engines and gas turbines, pressure fluctuations are always present, even during normal operation. One of design prerequisites for the engine combustors is stable operation, since large-amplitude self-sustained pressure fluctuations (also known as combustion instability) have the potential to cause serious structural damage and catastrophic engine failure. To dampen pressure fluctuations and to reduce noise, acoustic dampers are widely applied as a passive control means to stabilize combustion/engine systems. However, they cannot respond to the dynamic changes of operating conditions and tend to be effective over certain narrow range of frequencies. To maintain their optimum damping performance over a broad frequency range, extensive researches have been conducted during the past four decades. The present work is to summarize the status, challenges and progress of implementing such acoustic dampers on engine systems. The damping effect and mechanism of various acoustic dampers, such as Helmholtz resonators, perforated liners, baffles, half- and quarter-wave tube are introduced first. A summary of numerical, experimental and theoretical studies are then presented to review the progress made so far. Finally, as an alternative means, ';tunable acoustic dampers' are discussed. Potential, challenges and issues associated with the dampers practical implementation are highlighted.

Using quantum erasure to exorcize Maxwell's demon: I. Concepts and context

NASA Astrophysics Data System (ADS)

Scully, Marlan O.; Rostovtsev, Yuri; Sariyanni, Zoe-Elizabeth; Suhail Zubairy, M.

2005-10-01

Szilard [L. Szilard, Zeitschrift für Physik, 53 (1929) 840] made a decisive step toward solving the Maxwell demon problem by introducing and analyzing the single atom heat engine. Bennett [Sci. Am. 255 (1987) 107] completed the solution by pointing out that there must be an entropy, ΔS=kln2, generated as the result of information erased on each cycle. Nevertheless, others have disagreed. For example, philosophers such as Popper “have found the literature surrounding Maxwell's demon deeply problematic.” We propose and analyze a new kind of single atom quantum heat engine which allows us to resolve the Maxwell demon paradox simply, and without invoking the notions of information or entropy. The energy source of the present quantum engine [Scully, Phys. Rev. Lett. 87 (2001) 22601] is a Stern-Gerlach apparatus acting as a demonesque heat sorter. An isothermal compressor acts as the entropy sink. In order to complete a thermodynamic cycle, an energy of ΔW=kTln2 must be expended. This energy is essentially a “reset” or “eraser” energy. Thus Bennett's entropy ΔS=ΔW/T emerges as a simple consequence of the quantum thermodynamics of our heat engine. It would seem that quantum mechanics contains the kernel of information entropy at its very core. That is the concept of information erasure as it appears in quantum mechanics [Scully and Drühl, Phys. Rev. A 25 (1982) 2208] and the present quantum heat engine have a deep common origin.

Overview of Lightweight Structures for Rotorcraft Engines and Drivetrains

NASA Technical Reports Server (NTRS)

Roberts, Gary D.

2011-01-01

This is an overview presentation of research being performed in the Advanced Materials Task within the NASA Subsonic Rotary Wing Project. This research is focused on technology areas that address both national goals and project goals for advanced rotorcraft. Specific technology areas discussed are: (1) high temperature materials for advanced turbines in turboshaft engines; (2) polymer matrix composites for lightweight drive system components; (3) lightweight structure approaches for noise and vibration control; and (4) an advanced metal alloy for lighter weight bearings and more reliable mechanical components. An overview of the technology in each area is discussed, and recent accomplishments are presented.

FIBER-TEX 1991: The Fifth Conference on Advanced Engineering Fibers and Textile Structures for Composites

NASA Technical Reports Server (NTRS)

Buckley, John D. (Editor)

1992-01-01

This document is a compilation of papers presented at a joint NASA/North Carolina State University/DoD/Clemson University/Drexel University conference on Fibers, Textile Technology, and Composites Structures held at the College of Textiles Building on Centennial Campus of North Carolina State University, Raleigh, North Carolina on October 15-17, 1991. Conference papers presented information on advanced engineering fibers, textile processes and structures, structural fabric production, mechanics and characteristics of woven composites, pultruded composites, and the latest requirements for the use of textiles in the production of composite materials and structures.

40 CFR 1065.410 - Maintenance limits for stabilized test engines.

Code of Federal Regulations, 2013 CFR

2013-07-01

... engineering grade tools to identify bad engine components. Any equipment, instruments, or tools used for... no longer use it as an emission-data engine. Also, if your test engine has a major mechanical failure... your test engine has a major mechanical failure that requires you to take it apart, you may no longer...

40 CFR 1065.410 - Maintenance limits for stabilized test engines.

Code of Federal Regulations, 2012 CFR

2012-07-01

... engineering grade tools to identify bad engine components. Any equipment, instruments, or tools used for... no longer use it as an emission-data engine. Also, if your test engine has a major mechanical failure... your test engine has a major mechanical failure that requires you to take it apart, you may no longer...

Mechanical Engineering | Classification | College of Engineering & Applied

Science.gov Websites

ProfessorMechanical Engineering(414) 229-6949avdeev@uwm.eduEng & Math Sciences 975 profile photo Robert Balmer, Sc . D.Professor EmeritusMechanical Engineering(414) 229-3374balmer@uwm.eduEng & Math Sciences E260 profile -6614wjchang@uwm.eduEng & Math Sciences 1113 profile photo Junhong Chen Ph.D.UWM Distinguished

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

ERIC Educational Resources Information Center

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…

Integrating Communication into Engineering Curricula: An Interdisciplinary Approach to Facilitating Transfer at New Mexico Institute of Mining and Technology

ERIC Educational Resources Information Center

Ford, Julie Dyke

2012-01-01

This program profile describes a new approach towards integrating communication within Mechanical Engineering curricula. The author, who holds a joint appointment between Technical Communication and Mechanical Engineering at New Mexico Institute of Mining and Technology, has been collaborating with Mechanical Engineering colleagues to establish a…

Calcium-Magnesium-Alumino-Silicates (CMAS) Reaction Mechanisms and Resistance of Advanced Turbine Environmental Barrier Coatings for SiC/SiC Ceramic Matrix Composites

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Costa, Gustavo; Harder, Bryan J.; Wiesner, Valerie L.; Hurst, Janet B.; Puleo, Bernadette J.

2017-01-01

Environmental barrier coatings (EBCs) and SiC/SiC ceramic matrix composites (CMCs) systems will play a crucial role in future turbine engines for hot-section component applications because of their ability to significantly increase engine operating temperatures, reduce engine weight and cooling requirements. The development of prime-reliant environmental barrier coatings is an essential requirement to enable the applications of the 2700-3000 F EBC - CMC systems. This presentation primarily focuses on the reaction mechanisms of advanced NASA environmental barrier coating systems, when in contact with Calcium-Magnesium Alumino-Silicates (CMAS) at high temperatures. Advanced oxide-silicate defect cluster environmental barrier coatings are being designed for ultimate balanced controls of the EBC temperature capability and CMAS reactivity, thus improving the CMAS resistance. Further CMAS mitigation strategies are also discussed.

Hillslope hydrology and stability

USGS Publications Warehouse

Lu, Ning; Godt, Jonathan

2012-01-01

Landslides are caused by a failure of the mechanical balance within hillslopes. This balance is governed by two coupled physical processes: hydrological or subsurface flow and stress. The stabilizing strength of hillslope materials depends on effective stress, which is diminished by rainfall. This book presents a cutting-edge quantitative approach to understanding hydro-mechanical processes across variably saturated hillslope environments and to the study and prediction of rainfall-induced landslides. Topics covered include historic synthesis of hillslope geomorphology and hydrology, total and effective stress distributions, critical reviews of shear strength of hillslope materials and different bases for stability analysis. Exercises and homework problems are provided for students to engage with the theory in practice. This is an invaluable resource for graduate students and researchers in hydrology, geomorphology, engineering geology, geotechnical engineering and geomechanics and for professionals in the fields of civil and environmental engineering and natural hazard analysis.

Genetic engineering of woody plants: current and future targets in a stressful environment.

PubMed

Osakabe, Yuriko; Kajita, Shinya; Osakabe, Keishi

2011-06-01

Abiotic stress is a major factor in limiting plant growth and productivity. Environmental degradation, such as drought and salinity stresses, will become more severe and widespread in the world. To overcome severe environmental stress, plant biotechnologies, such as genetic engineering in woody plants, need to be implemented. The adaptation of plants to environmental stress is controlled by cascades of molecular networks including cross-talk with other stress signaling mechanisms. The present review focuses on recent studies concerning genetic engineering in woody plants for the improvement of the abiotic stress responses. Furthermore, it highlights the recent advances in the understanding of molecular responses to stress. The review also summarizes the basis of a molecular mechanism for cell wall biosynthesis and the plant hormone responses to regulate tree growth and biomass in woody plants. This would facilitate better understanding of the control programs of biomass production under stressful conditions. Copyright © Physiologia Plantarum 2011.

Interfacing modules for integrating discipline specific structural mechanics codes

NASA Technical Reports Server (NTRS)

Endres, Ned M.

1989-01-01

An outline of the organization and capabilities of the Engine Structures Computational Simulator (Simulator) at NASA Lewis Research Center is given. One of the goals of the research at Lewis is to integrate various discipline specific structural mechanics codes into a software system which can be brought to bear effectively on a wide range of engineering problems. This system must possess the qualities of being effective and efficient while still remaining user friendly. The simulator was initially designed for the finite element simulation of gas jet engine components. Currently, the simulator has been restricted to only the analysis of high pressure turbine blades and the accompanying rotor assembly, although the current installation can be expanded for other applications. The simulator presently assists the user throughout its procedures by performing information management tasks, executing external support tasks, organizing analysis modules and executing these modules in the user defined order while maintaining processing continuity.

The Impact of Biomechanics in Tissue Engineering and Regenerative Medicine

PubMed Central

Butler, David L.; Goldstein, Steven A.; Guo, X. Edward; Kamm, Roger; Laurencin, Cato T.; McIntire, Larry V.; Mow, Van C.; Nerem, Robert M.; Sah, Robert L.; Soslowsky, Louis J.; Spilker, Robert L.; Tranquillo, Robert T.

2009-01-01

Biomechanical factors profoundly influence the processes of tissue growth, development, maintenance, degeneration, and repair. Regenerative strategies to restore damaged or diseased tissues in vivo and create living tissue replacements in vitro have recently begun to harness advances in understanding of how cells and tissues sense and adapt to their mechanical environment. It is clear that biomechanical considerations will be fundamental to the successful development of clinical therapies based on principles of tissue engineering and regenerative medicine for a broad range of musculoskeletal, cardiovascular, craniofacial, skin, urinary, and neural tissues. Biomechanical stimuli may in fact hold the key to producing regenerated tissues with high strength and endurance. However, many challenges remain, particularly for tissues that function within complex and demanding mechanical environments in vivo. This paper reviews the present role and potential impact of experimental and computational biomechanics in engineering functional tissues using several illustrative examples of past successes and future grand challenges. PMID:19583462

Engineering and Fabrication Considerations for Cost-Effective Space Reactor Shield Development

NASA Astrophysics Data System (ADS)

Berg, Thomas A.; Disney, Richard K.

2004-02-01

Investment in developing nuclear power for space missions cannot be made on the basis of a single mission. Current efforts in the design and fabrication of the reactor module, including the reactor shield, must be cost-effective and take into account scalability and fabricability for planned and future missions. Engineering considerations for the shield need to accommodate passive thermal management, varying radiation levels and effects, and structural/mechanical issues. Considering these challenges, design principles and cost drivers specific to the engineering and fabrication of the reactor shield are presented that contribute to lower recurring mission costs.

Engineering and Fabrication Considerations for Cost-Effective Space Reactor Shield Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berg, Thomas A.; Disney, Richard K.

Investment in developing nuclear power for space missions cannot be made on the basis of a single mission. Current efforts in the design and fabrication of the reactor module, including the reactor shield, must be cost-effective and take into account scalability and fabricability for planned and future missions. Engineering considerations for the shield need to accommodate passive thermal management, varying radiation levels and effects, and structural/mechanical issues. Considering these challenges, design principles and cost drivers specific to the engineering and fabrication of the reactor shield are presented that contribute to lower recurring mission costs.

Processing study of injection molding of silicon nitride for engine applications

NASA Technical Reports Server (NTRS)

Rorabaugh, M. E.; Yeh, H. C.

1985-01-01

The high hardness of silicon nitride, which is currently under consideration as a structural material for such hot engine components as turbine blades, renders machining of the material prohibitively costly; the near net shape forming technique of injection molding is accordingly favored as a means for component fabrication. Attention is presently given to the relationships between injection molding processing parameters and the resulting microstructural and mechanical properties of the resulting engine parts. An experimental program has been conducted under NASA sponsorship which tests the quality of injection molded bars of silicon nitride at various stages of processing.

A New, Highly Improved Two-Cycle Engine

NASA Technical Reports Server (NTRS)

Wiesen, Bernard

2008-01-01

The figure presents a cross-sectional view of a supercharged, variable-compression, two-cycle, internal-combustion engine that offers significant advantages over prior such engines. The improvements are embodied in a combination of design changes that contribute synergistically to improvements in performance and economy. Although the combination of design changes and the principles underlying them are complex, one of the main effects of the changes on the overall engine design is reduced (relative to prior two-cycle designs) mechanical complexity, which translates directly to reduced manufacturing cost and increased reliability. Other benefits include increases in the efficiency of both scavenging and supercharging. The improvements retain the simplicity and other advantages of two-cycle engines while affording increases in volumetric efficiency and performance across a wide range of operating conditions that, heretofore have been accessible to four-cycle engines but not to conventionally scavenged two-cycle ones, thereby increasing the range of usefulness of the two-cycle engine into all areas now dominated by the four-cycle engine. The design changes and benefits are too numerous to describe here in detail, but it is possible to summarize the major improvements: Reciprocating Shuttle Inlet Valve The entire reciprocating shuttle inlet valve and its operating gear is constructed as a single member. The shuttle valve is actuated in a lost-motion arrangement in which, at the ends of its stroke, projections on the shuttle valve come to rest against abutments at the ends of grooves in a piston skirt. This shuttle-valve design obviates the customary complex valve mechanism, actuated from an engine crankshaft or camshaft, yet it is effective with every type of two-cycle engine, from small high-speed single cylinder model engines, to large low-speed multiple cylinder engines.

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

ERIC Educational Resources Information Center

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…

Structure and Mechanics

NASA Technical Reports Server (NTRS)

Sanger, George

1991-01-01

Artemis is a Common Lunar Lander (CLL) design for the Space Exploration Initiative (SEI). Structure factors for the CLL's primary and secondary structures are listed in tabular form. Additionally, engineering drawings of various systems, including the propulsion and landing systems, are presented.

Multifunctional centrifugal grinding unit

NASA Astrophysics Data System (ADS)

Sevostyanov, V. S.; Uralskij, V. I.; Uralskij, A. V.; Sinitsa, E. V.

2018-03-01

The article presents scientific and engineering developments of multifunctional centrifugal grinding unit in which the selective effect of grinding bodies on the crushing material is realized, depending on its physical and mechanical characteristics and various schemes for organizing the technological process

The Management of Building Environment for Comfort and Energy Conservation. Final Report.

ERIC Educational Resources Information Center

North Seattle Community Coll., WA.

This report presents materials from a Washington State project to develop a curriculum outline of three courses for energy conservation to be used in vocational supplement classes. It first presents results from an industrial survey on which engineers, architects, and mechanical contractors rated objectives for the three courses. Next are provided…

Heat engine driven by purely quantum information.

PubMed

Park, Jung Jun; Kim, Kang-Hwan; Sagawa, Takahiro; Kim, Sang Wook

2013-12-06

The key question of this Letter is whether work can be extracted from a heat engine by using purely quantum mechanical information. If the answer is yes, what is its mathematical formula? First, by using a bipartite memory we show that the work extractable from a heat engine is bounded not only by the free energy change and the sum of the entropy change of an individual memory but also by the change of quantum mutual information contained inside the memory. We then find that the engine can be driven by purely quantum information, expressed as the so-called quantum discord, forming a part of the quantum mutual information. To confirm it, as a physical example we present the Szilard engine containing a diatomic molecule with a semipermeable wall.

It's all in the timing: modeling isovolumic contraction through development and disease with a dynamic dual electromechanical bioreactor system.

PubMed

Morgan, Kathy Ye; Black, Lauren Deems

2014-01-01

This commentary discusses the rationale behind our recently reported work entitled "Mimicking isovolumic contraction with combined electromechanical stimulation improves the development of engineered cardiac constructs," introduces new data supporting our hypothesis, and discusses future applications of our bioreactor system. The ability to stimulate engineered cardiac tissue in a bioreactor system that combines both electrical and mechanical stimulation offers a unique opportunity to simulate the appropriate dynamics between stretch and contraction and model isovolumic contraction in vitro. Our previous study demonstrated that combined electromechanical stimulation that simulated the timing of isovolumic contraction in healthy tissue improved force generation via increased contractile and calcium handling protein expression and improved hypertrophic pathway activation. In new data presented here, we further demonstrate that modification of the timing between electrical and mechanical stimulation to mimic a non-physiological process negatively impacts the functionality of the engineered constructs. We close by exploring the various disease states that have altered timing between the electrical and mechanical stimulation signals as potential future directions for the use of this system.

Multiscale design and synthesis of biomimetic gradient protein/biosilica composites for interfacial tissue engineering.

PubMed

Guo, Jin; Li, Chunmei; Ling, Shengjie; Huang, Wenwen; Chen, Ying; Kaplan, David L

2017-11-01

Continuous gradients present at tissue interfaces such as osteochondral systems, reflect complex tissue functions and involve changes in extracellular matrix compositions, cell types and mechanical properties. New and versatile biomaterial strategies are needed to create suitable biomimetic engineered grafts for interfacial tissue engineering. Silk protein-based composites, coupled with selective peptides with mineralization domains, were utilized to mimic the soft-to-hard transition in osteochondral interfaces. The gradient composites supported tunable mineralization and mechanical properties corresponding to the spatial concentration gradient of the mineralization domains (R5 peptide). The composite system exhibited continuous transitions in terms of composition, structure and mechanical properties, as well as cytocompatibility and biodegradability. The gradient silicified silk/R5 composites promoted and regulated osteogenic differentiation of human mesenchymal stem cells in an osteoinductive environment in vitro. The cells differentiated along the composites in a manner consistent with the R5-gradient profile. This novel biomimetic gradient biomaterial design offers a useful approach to meet a broad range of needs in regenerative medicine. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fibrin gels exhibit improved biological, structural, and mechanical properties compared with collagen gels in cell-based tendon tissue-engineered constructs.

PubMed

Breidenbach, Andrew P; Dyment, Nathaniel A; Lu, Yinhui; Rao, Marepalli; Shearn, Jason T; Rowe, David W; Kadler, Karl E; Butler, David L

2015-02-01

The prevalence of tendon and ligament injuries and inadequacies of current treatments is driving the need for alternative strategies such as tissue engineering. Fibrin and collagen biopolymers have been popular materials for creating tissue-engineered constructs (TECs), as they exhibit advantages of biocompatibility and flexibility in construct design. Unfortunately, a few studies have directly compared these materials for tendon and ligament applications. Therefore, this study aims at determining how collagen versus fibrin hydrogels affect the biological, structural, and mechanical properties of TECs during formation in vitro. Our findings show that tendon and ligament progenitor cells seeded in fibrin constructs exhibit improved tenogenic gene expression patterns compared with their collagen-based counterparts for approximately 14 days in culture. Fibrin-based constructs also exhibit improved cell-derived collagen alignment, increased linear modulus (2.2-fold greater) compared with collagen-based constructs. Cyclic tensile loading, which promotes the maturation of tendon constructs in a previous work, exhibits a material-dependent effect in this study. Fibrin constructs show trending reductions in mechanical, biological, and structural properties, whereas collagen constructs only show improved tenogenic expression in the presence of mechanical stimulation. These findings highlight that components of the mechanical stimulus (e.g., strain amplitude or time of initiation) need to be tailored to the material and cell type. Given the improvements in tenogenic expression, extracellular matrix organization, and material properties during static culture, in vitro findings presented here suggest that fibrin-based constructs may be a more suitable alternative to collagen-based constructs for tissue-engineered tendon/ligament repair.

Fibrin Gels Exhibit Improved Biological, Structural, and Mechanical Properties Compared with Collagen Gels in Cell-Based Tendon Tissue-Engineered Constructs

PubMed Central

Dyment, Nathaniel A.; Lu, Yinhui; Rao, Marepalli; Shearn, Jason T.; Rowe, David W.; Kadler, Karl E.; Butler, David L.

2015-01-01

The prevalence of tendon and ligament injuries and inadequacies of current treatments is driving the need for alternative strategies such as tissue engineering. Fibrin and collagen biopolymers have been popular materials for creating tissue-engineered constructs (TECs), as they exhibit advantages of biocompatibility and flexibility in construct design. Unfortunately, a few studies have directly compared these materials for tendon and ligament applications. Therefore, this study aims at determining how collagen versus fibrin hydrogels affect the biological, structural, and mechanical properties of TECs during formation in vitro. Our findings show that tendon and ligament progenitor cells seeded in fibrin constructs exhibit improved tenogenic gene expression patterns compared with their collagen-based counterparts for approximately 14 days in culture. Fibrin-based constructs also exhibit improved cell-derived collagen alignment, increased linear modulus (2.2-fold greater) compared with collagen-based constructs. Cyclic tensile loading, which promotes the maturation of tendon constructs in a previous work, exhibits a material-dependent effect in this study. Fibrin constructs show trending reductions in mechanical, biological, and structural properties, whereas collagen constructs only show improved tenogenic expression in the presence of mechanical stimulation. These findings highlight that components of the mechanical stimulus (e.g., strain amplitude or time of initiation) need to be tailored to the material and cell type. Given the improvements in tenogenic expression, extracellular matrix organization, and material properties during static culture, in vitro findings presented here suggest that fibrin-based constructs may be a more suitable alternative to collagen-based constructs for tissue-engineered tendon/ligament repair. PMID:25266738

Fabrication, characterization, and biocompatibility assessment of a novel elastomeric nanofibrous scaffold: A potential scaffold for soft tissue engineering.

PubMed

Shamirzaei Jeshvaghani, Elham; Ghasemi-Mobarakeh, Laleh; Mansurnezhad, Reza; Ajalloueian, Fatemeh; Kharaziha, Mahshid; Dinari, Mohammad; Sami Jokandan, Maryam; Chronakis, Ioannis S

2017-11-23

With regard to flexibility and strength properties requirements of soft biological tissue, elastomeric materials could be more beneficial in soft tissue engineering applications. The present work investigates the use of an elastic polymer, (polycaprolactone fumarate [PCLF]), for fabricating an electrospun scaffold. PCLF with number-average molecular weight of 13,284 g/mol was synthetized, electrospun PCLF:polycaprolactone (PCL) (70:30) nanofibrous scaffolds were fabricated and a novel strategy (in situ photo-crosslinking along with wet electrospinning) was applied for crosslinking of PCLF in the structure of PCLF:PCL nanofibers was presented. Sol fraction results, Fourier-transform infrared spectroscopy, and mechanical tests confirmed occurrence of crosslinking reaction. Strain at break and Young's modulus of crosslinked PCLF:PCL nanofibers fabricated was found to be 114.5 ± 3.9% and 0.6 ± 0.1 MPa, respectively, and dynamic mechanical analysis results revealed elasticity of nanofibers. MTS assay showed biocompatibility of PCLF:PCL (70:30) nanofibrous scaffolds. Our overall results showed that electrospun PCLF:PCL nanofibrous scaffold could be considered as a candidate for further in vitro and in vivo experiments and its application for engineering of soft tissues subjected to in vivo cyclic mechanical stresses. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2017. © 2017 Wiley Periodicals, Inc.

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.

PubMed

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.

Magnetic Gearboxes for Aerospace Applications

NASA Technical Reports Server (NTRS)

Perez-Diaz, Jose Luis; Diez-Jimenez, Efren; Alvarez-Valenzuela, Marco A.; Sanchez-Garcia-Casarrubios, Juan; Cristache, Christian; Valiente-Blanco, Ignacio

2014-01-01

Magnetic gearboxes are contactless mechanisms for torque-speed conversion. They present no wear, no friction and no fatigue. They need no lubricant and can be customized for other mechanical properties as stiffness or damping. Additionally, they can protect structures and mechanisms against overloads, limitting the transmitted torque. In this work, spur, planetary and "magdrive" or "harmonic drive" configurations are compared considering their use in aerospace applications. The most recent test data are summarized to provide some useful help for the design engineer.

Effect of Nanoparticle Incorporation and Surface Coating on Mechanical Properties of Bone Scaffolds: A Brief Review

PubMed Central

Corona-Gomez, Jesus; Chen, Xiongbiao; Yang, Qiaoqin

2016-01-01

Mechanical properties of a scaffold play an important role in its in vivo performance in bone tissue engineering, due to the fact that implanted scaffolds are typically subjected to stress including compression, tension, torsion, and shearing. Unfortunately, not all the materials used to fabricate scaffolds are strong enough to mimic native bones. Extensive research has been conducted in order to increase scaffold strength and mechanical performance by incorporating nanoparticles and/or coatings. An incredible improvement has been achieved; and some outstanding examples are the usage of nanodiamond, hydroxyapatite, bioactive glass particles, SiO2, MgO, and silver nanoparticles. This review paper aims to present the results, to summarize significant findings, and to give perspective for future work, which could be beneficial to future bone tissue engineering. PMID:27420104

Recent advances in engineering science; Proceedings of the A. Cemal Eringen Symposium, University of California, Berkeley, June 20-22, 1988

NASA Technical Reports Server (NTRS)

Koh, Severino L. (Editor); Speziale, Charles G. (Editor)

1989-01-01

Various papers on recent advances in engineering science are presented. Some individual topics addressed include: advances in adaptive methods in computational fluid mechanics, mixtures of two medicomorphic materials, computer tests of rubber elasticity, shear bands in isotropic micropolar elastic materials, nonlinear surface wave and resonator effects in magnetostrictive crystals, simulation of electrically enhanced fibrous filtration, plasticity theory of granular materials, dynamics of viscoelastic media with internal oscillators, postcritical behavior of a cantilever bar, boundary value problems in nonlocal elasticity, stability of flexible structures with random parameters, electromagnetic tornadoes in earth's ionosphere and magnetosphere, helicity fluctuations and the energy cascade in turbulence, mechanics of interfacial zones in bonded materials, propagation of a normal shock in a varying area duct, analytical mechanics of fracture and fatigue.

Combined analytical and numerical approaches in Dynamic Stability analyses of engineering systems

NASA Astrophysics Data System (ADS)

Náprstek, Jiří

2015-03-01

Dynamic Stability is a widely studied area that has attracted many researchers from various disciplines. Although Dynamic Stability is usually associated with mechanics, theoretical physics or other natural and technical disciplines, it is also relevant to social, economic, and philosophical areas of our lives. Therefore, it is useful to occasionally highlight the general aspects of this amazing area, to present some relevant examples and to evaluate its position among the various branches of Rational Mechanics. From this perspective, the aim of this study is to present a brief review concerning the Dynamic Stability problem, its basic definitions and principles, important phenomena, research motivations and applications in engineering. The relationships with relevant systems that are prone to stability loss (encountered in other areas such as physics, other natural sciences and engineering) are also noted. The theoretical background, which is applicable to many disciplines, is presented. In this paper, the most frequently used Dynamic Stability analysis methods are presented in relation to individual dynamic systems that are widely discussed in various engineering branches. In particular, the Lyapunov function and exponent procedures, Routh-Hurwitz, Liénard, and other theorems are outlined together with demonstrations. The possibilities for analytical and numerical procedures are mentioned together with possible feedback from experimental research and testing. The strengths and shortcomings of these approaches are evaluated together with examples of their effective complementing of each other. The systems that are widely encountered in engineering are presented in the form of mathematical models. The analyses of their Dynamic Stability and post-critical behaviour are also presented. The stability limits, bifurcation points, quasi-periodic response processes and chaotic regimes are discussed. The limit cycle existence and stability are examined together with their separating roles as attractors and repulsers. Two levels of stability loss (recovery of the system is possible or final collapse is inevitable) as can be observed in softening systems are noted. Time-limited excitation and relevant transition effects (e.g., seismic excitation) are also discussed, together with the evaluation of possible system reliability improvement. The Dynamic Stability investigation of two degrees-of-freedom aero-elastic systems in a linear formulation using several approaches is briefly highlighted. Further systems modelling problems that arise in transport engineering are also outlined. A few hints for applications are given. Some open problems and possible future research strategies are outlined.

Knowledge-based personalized search engine for the Web-based Human Musculoskeletal System Resources (HMSR) in biomechanics.

PubMed

Dao, Tien Tuan; Hoang, Tuan Nha; Ta, Xuan Hien; Tho, Marie Christine Ho Ba

2013-02-01

Human musculoskeletal system resources of the human body are valuable for the learning and medical purposes. Internet-based information from conventional search engines such as Google or Yahoo cannot response to the need of useful, accurate, reliable and good-quality human musculoskeletal resources related to medical processes, pathological knowledge and practical expertise. In this present work, an advanced knowledge-based personalized search engine was developed. Our search engine was based on a client-server multi-layer multi-agent architecture and the principle of semantic web services to acquire dynamically accurate and reliable HMSR information by a semantic processing and visualization approach. A security-enhanced mechanism was applied to protect the medical information. A multi-agent crawler was implemented to develop a content-based database of HMSR information. A new semantic-based PageRank score with related mathematical formulas were also defined and implemented. As the results, semantic web service descriptions were presented in OWL, WSDL and OWL-S formats. Operational scenarios with related web-based interfaces for personal computers and mobile devices were presented and analyzed. Functional comparison between our knowledge-based search engine, a conventional search engine and a semantic search engine showed the originality and the robustness of our knowledge-based personalized search engine. In fact, our knowledge-based personalized search engine allows different users such as orthopedic patient and experts or healthcare system managers or medical students to access remotely into useful, accurate, reliable and good-quality HMSR information for their learning and medical purposes. Copyright © 2012 Elsevier Inc. All rights reserved.

Design of a miniature hydrogen fueled gas turbine engine

NASA Technical Reports Server (NTRS)

Burnett, M.; Lopiccolo, R. C.; Simonson, M. R.; Serovy, G. K.; Okiishi, T. H.; Miller, M. J.; Sisto, F.

1973-01-01

The design, development, and delivery of a miniature hydrogen-fueled gas turbine engine are discussed. The engine was to be sized to approximate a scaled-down lift engine such as the teledyne CAE model 376. As a result, the engine design emerged as a 445N(100 lb.)-thrust engine flowing 0.86 kg (1.9 lbs.) air/sec. A 4-stage compressor was designed at a 4.0 to 1 pressure ratio for the above conditions. The compressor tip diameter was 9.14 cm (3.60 in.). To improve overall engine performance, another compressor with a 4.75 to 1 pressure ratio at the same tip diameter was designed. A matching turbine for each compressor was also designed. The turbine tip diameter was 10.16 cm (4.0 in.). A combustion chamber was designed, built, and tested for this engine. A preliminary design of the mechanical rotating parts also was completed and is discussed. Three exhaust nozzle designs are presented.

Advanced online control mode selection for gas turbine aircraft engines

NASA Astrophysics Data System (ADS)

Wiseman, Matthew William

The modern gas turbine aircraft engine is a complex, highly nonlinear system the operates in a widely varying environment. Traditional engine control techniques based on the hydro mechanical control concepts of early turbojet engines are unable to deliver the performance required from today's advanced engine designs. A new type of advanced control utilizing multiple control modes and an online mode selector is investigated, and various strategies for improving the baseline mode selection architecture are introduced. The ability to five-tune actuator command outputs is added to the basic mode selection and blending process, and mode selection designs that we valid for the entire flight envelope are presented. Methods for optimizing the mode selector to improve overall engine performance are also discussed. Finally, using flight test data from a GE F110-powered F16 aircraft, the full-envelope mode selector designs are validated and shown to provide significant performance benefits. Specifically, thrust command tracking is enhanced while critical engine limits are protected, with very little impact on engine efficiency.

Welcoming speech from Dean Faculty of Mechanical Engineering, UMP

NASA Astrophysics Data System (ADS)

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

Learning analytics for smart campus: Data on academic performances of engineering undergraduates in Nigerian private university.

PubMed

Popoola, Segun I; Atayero, Aderemi A; Badejo, Joke A; John, Temitope M; Odukoya, Jonathan A; Omole, David O

2018-04-01

Empirical measurement, monitoring, analysis, and reporting of learning outcomes in higher institutions of developing countries may lead to sustainable education in the region. In this data article, data about the academic performances of undergraduates that studied engineering programs at Covenant University, Nigeria are presented and analyzed. A total population sample of 1841 undergraduates that studied Chemical Engineering (CHE), Civil Engineering (CVE), Computer Engineering (CEN), Electrical and Electronics Engineering (EEE), Information and Communication Engineering (ICE), Mechanical Engineering (MEE), and Petroleum Engineering (PET) within the year range of 2002-2014 are randomly selected. For the five-year study period of engineering program, Grade Point Average (GPA) and its cumulative value of each of the sample were obtained from the Department of Student Records and Academic Affairs. In order to encourage evidence-based research in learning analytics, detailed datasets are made publicly available in a Microsoft Excel spreadsheet file attached to this article. Descriptive statistics and frequency distributions of the academic performance data are presented in tables and graphs for easy data interpretations. In addition, one-way Analysis of Variance (ANOVA) and multiple comparison post-hoc tests are performed to determine whether the variations in the academic performances are significant across the seven engineering programs. The data provided in this article will assist the global educational research community and regional policy makers to understand and optimize the learning environment towards the realization of smart campuses and sustainable education.

Instrumental Analysis Chemistry Laboratory

ERIC Educational Resources Information Center

Munoz de la Pena, Arsenio; Gonzalez-Gomez, David; Munoz de la Pena, David; Gomez-Estern, Fabio; Sequedo, Manuel Sanchez

2013-01-01

designed for automating the collection and assessment of laboratory exercises is presented. This Web-based system has been extensively used in engineering courses such as control systems, mechanics, and computer programming. Goodle GMS allows the students to submit their results to a…

WATER TREATMENT AND EDUCATION IN VILLAHERMOSA, MEXICO

EPA Science Inventory

The interdisciplinary P3 team included mechanical, civil and environmental, and electrical engineers. This was critical to overcome the technical challenges presented by this project. A successful full-scale system was developed that greatly reduces the probability of contract...

Shake, Rattle, and Roll: Nonlinear Dynamics in Mechanical Engineering

NASA Astrophysics Data System (ADS)

Shaw, Steven

1997-03-01

This presentation will focus on three mechanical engineering applications in which methods from nonlinear dynamics have been applied with success. Each topic will be briefly surveyed by outlining the development of a mathematical model, providing a description of the analysis tools employed, and showing the main results obtained. The applications are: vibration reduction in internal combustion engines, impact dynamics of mechanical components, and the dynamics of ship capsize. The first topic demonstrates a novel arrangement of dynamic absorbers that can be used for attenuating torsional vibrations in rotating machinery. The operation of this device takes advantage of a purely nonlinear system response that results from a period doubling bifurcation. This configuration is more effective than existing absorbers and it cannot be imagined by using naive extensions of linear vibration theory. The second topic deals with the dynamics of mechanical systems in which components make intermittent contact with each another. Such dynamics are often the source of undesirable noise and wear in machinery and can be extremely complicated. Results obtained from simple predictive models and some application areas will be presented for these impacting systems. The final topic deals with the gross motions of seagoing vessels and their stability against capsize. Existing safety regulations for ship stability are based on purely static measures, whereas capsize is an inherently nonlinear dynamic event. An overview will be given that considers some basic modeling issues, dynamic analysis techniques (based on the concept of chaotic phase-space transport), and the resulting predictive tools that have been developed for this class of problems.

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

ERIC Educational Resources Information Center

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…

Job Prospects for Mechanical Engineers.

ERIC Educational Resources Information Center

Basta, Nicholas

1986-01-01

Discusses the career outlook for mechanical engineers. Explains that the number of bachelor degrees awarded yearly has reached a plateau, but salaries continue to rise. Suggests that the largest increase in demand for mechanical engineers will come from industries involved in automation, particularly those developing robotics. (TW)

Elements of Engineering Excellence

NASA Technical Reports Server (NTRS)

Blair, J. C.; Ryan, R. S.; Schutzenhofer

2012-01-01

The inspiration for this Contract Report (CR) originated in discussions with the director of Marshall Space Flight Center (MSFC) Engineering who asked that we investigate the question: "How do you achieve excellence in aerospace engineering?" Engineering a space system is a complex activity. Avoiding its inherent potential pitfalls and achieving a successful product is a challenge. This CR presents one approach to answering the question of how to achieve Engineering Excellence. We first investigated the root causes of NASA major failures as a basis for developing a proposed answer to the question of Excellence. The following discussions integrate a triad of Technical Understanding and Execution, Partnership with the Project, and Individual and Organizational Culture. The thesis is that you must focus on the whole process and its underlying culture, not just on the technical aspects. In addition to the engineering process, emphasis is given to the need and characteristics of a Learning Organization as a mechanism for changing the culture.

Apparatus and method for operating internal combustion engines from variable mixtures of gaseous fuels

DOEpatents

Heffel, James W [Lake Matthews, CA; Scott, Paul B [Northridge, CA; Park, Chan Seung [Yorba Linda, CA

2011-11-01

An apparatus and method for utilizing any arbitrary mixture ratio of multiple fuel gases having differing combustion characteristics, such as natural gas and hydrogen gas, within an internal combustion engine. The gaseous fuel composition ratio is first sensed, such as by thermal conductivity, infrared signature, sound propagation speed, or equivalent mixture differentiation mechanisms and combinations thereof which are utilized as input(s) to a "multiple map" engine control module which modulates selected operating parameters of the engine, such as fuel injection and ignition timing, in response to the proportions of fuel gases available so that the engine operates correctly and at high efficiency irrespective of the gas mixture ratio being utilized. As a result, an engine configured according to the teachings of the present invention may be fueled from at least two different fuel sources without admixing constraints.

Apparatus and method for operating internal combustion engines from variable mixtures of gaseous fuels

DOEpatents

Heffel, James W.; Scott, Paul B.

2003-09-02

An apparatus and method for utilizing any arbitrary mixture ratio of multiple fuel gases having differing combustion characteristics, such as natural gas and hydrogen gas, within an internal combustion engine. The gaseous fuel composition ratio is first sensed, such as by thermal conductivity, infrared signature, sound propagation speed, or equivalent mixture differentiation mechanisms and combinations thereof which are utilized as input(s) to a "multiple map" engine control module which modulates selected operating parameters of the engine, such as fuel injection and ignition timing, in response to the proportions of fuel gases available so that the engine operates correctly and at high efficiency irrespective of the gas mixture ratio being utilized. As a result, an engine configured according to the teachings of the present invention may be fueled from at least two different fuel sources without admixing constraints.

Failure mode analysis to predict product reliability.

NASA Technical Reports Server (NTRS)

Zemanick, P. P.

1972-01-01

The failure mode analysis (FMA) is described as a design tool to predict and improve product reliability. The objectives of the failure mode analysis are presented as they influence component design, configuration selection, the product test program, the quality assurance plan, and engineering analysis priorities. The detailed mechanics of performing a failure mode analysis are discussed, including one suggested format. Some practical difficulties of implementation are indicated, drawn from experience with preparing FMAs on the nuclear rocket engine program.

Corrosion engineering in the utilization of the Raft River geothermal resource

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, R.L.

1976-08-01

The economic impact of corrosion and the particular problems of corrosion in the utilization of geothermal energy resources are noted. Corrosion is defined and the parameters that control corrosion in geothermal systems are discussed. A general background of corrosion is presented in the context of the various forms of corrosion, in relation to the Raft River geothermal system. A basic reference for mechanical design engineers involved in the design of geothermal energy recovery systems is provided.

Biomaterials for Tissue Engineering

PubMed Central

Lee, Esther J.; Kasper, F. Kurtis; Mikos, Antonios G.

2013-01-01

Biomaterials serve as an integral component of tissue engineering. They are designed to provide architectural framework reminiscent of native extracellular matrix in order to encourage cell growth and eventual tissue regeneration. Bone and cartilage represent two distinct tissues with varying compositional and mechanical properties. Despite these differences, both meet at the osteochondral interface. This article presents an overview of current biomaterials employed in bone and cartilage applications, discusses some design considerations, and alludes to future prospects within this field of research. PMID:23820768

Mechanical evaluation of nHAp scaffold coated with poly-3-hydroxybutyrate for bone tissue engineering.

PubMed

Foroughi, Mohammad Reza; Karbasi, Saeed; Ebrahimi-Kahrizsangi, Reza

2013-02-01

Regeneration of bone, cartilage and osteochondral tissues by tissue engineering has attracted intense attention due to its potential advantages over the traditional replacement of tissues with synthetic implants. Nevertheless, there is still a dearth of ideal or suitable scaffolds based on porous biomaterials, and the present study was undertaken to develop and evaluate a useful porous composite scaffold system. In this study, nano hydroxyapatite (nHAp) powder made (about 35-45 nm) by heating at temperature of 900 degrees C and porous hydroxyapatite (40, 50 and 60 wt% solution) for making scaffold, by using Polyurethane sponge replication method. In order to increase the scaffolds mechanical properties, they coated with 2, 4 and 6 wt% Poly-3-hydroxybutyrate (P3HB) for 30 sec and 60 sec, respectively; after the scaffold coated by Polymer and survey results, this scaffold is nHAp/P3HB composite. Based on these results, this scaffold is an optimized one among three tested above mentioned composition and can be utilized in bone tissue engineering. In the result, the best of scaffold is with 50 wt% HAp and 6 wt% P3HB and porosity of present is between 80-90% with compressive strength and modulus 1.51 MPa and 22.73 MPa, respectively, that it can be application in bone tissue engineering.

Double patterning from design enablement to verification

NASA Astrophysics Data System (ADS)

Abercrombie, David; Lacour, Pat; El-Sewefy, Omar; Volkov, Alex; Levine, Evgueni; Arb, Kellen; Reid, Chris; Li, Qiao; Ghosh, Pradiptya

2011-11-01

Litho-etch-litho-etch (LELE) is the double patterning (DP) technology of choice for 20 nm contact, via, and lower metal layers. We discuss the unique design and process characteristics of LELE DP, the challenges they present, and various solutions. ∘ We examine DP design methodologies, current DP conflict feedback mechanisms, and how they can help designers identify and resolve conflicts. ∘ In place and route (P&R), the placement engine must now be aware of the assumptions made during IP cell design, and use placement directives provide by the library designer. We examine the new effects DP introduces in detail routing, discuss how multiple choices of LELE and the cut allowances can lead to different solutions, and describe new capabilities required by detail routers and P&R engines. ∘ We discuss why LELE DP cuts and overlaps are critical to optical process correction (OPC), and how a hybrid mechanism of rule and model-based overlap generation can provide a fast and effective solution. ∘ With two litho-etch steps, mask misalignment and image rounding are now verification considerations. We present enhancements to the OPCVerify engine that check for pinching and bridging in the presence of DP overlay errors and acute angles.

DI Diesel Performance and Emissions Model

DTIC Science & Technology

1998-03-31

Skeletal mechanism for NOx chemistry in Diesel engines ," SAE Paper 981450. Mori, K. (1997), "Worldwide...Based on the review discussed above, Mellor et al. (1998) postulate a skeletal mechanism for NO chemistry in DI Diesel engines . This mechanism is... mechanism for NOx chemistry in Diesel engines ," SAE Paper 981450. Various Internal Ford Reports, Ford Motor Company, Dearborn, MI. 29

Gasoline Engine Mechanics. Florida Vocational Program Guide.

ERIC Educational Resources Information Center

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…

Progress of a Cross-Correlation Based Optical Strain Measurement Technique for Detecting Radial Growth on a Rotating Disk

NASA Technical Reports Server (NTRS)

Clem, Michelle M.; Abdul-Aziz, Ali; Woike, Mark R.; Fralick, Gustave C.

2015-01-01

The modern turbine engine operates in a harsh environment at high speeds and is repeatedly exposed to combined high mechanical and thermal loads. The cumulative effects of these external forces lead to high stresses and strains on the engine components, such as the rotating turbine disks, which may eventually lead to a catastrophic failure if left undetected. The operating environment makes it difficult to use conventional strain gauges, therefore, non-contact strain measurement techniques is of interest to NASA and the turbine engine community. This presentation describes one such approach; the use of cross correlation analysis to measure strain experienced by the engine turbine disk with the goal of assessing potential faults and damage.

From Structure-Function Analyses to Protein Engineering for Practical Applications of DNA Ligase

PubMed Central

Tanabe, Maiko; Nishida, Hirokazu

2015-01-01

DNA ligases are indispensable in all living cells and ubiquitous in all organs. DNA ligases are broadly utilized in molecular biology research fields, such as genetic engineering and DNA sequencing technologies. Here we review the utilization of DNA ligases in a variety of in vitro gene manipulations, developed over the past several decades. During this period, fewer protein engineering attempts for DNA ligases have been made, as compared to those for DNA polymerases. We summarize the recent progress in the elucidation of the DNA ligation mechanisms obtained from the tertiary structures solved thus far, in each step of the ligation reaction scheme. We also present some examples of engineered DNA ligases, developed from the viewpoint of their three-dimensional structures. PMID:26508902

An Exact Efficiency Formula for Holographic Heat Engines

DOE PAGES

Johnson, Clifford

2016-03-31

Further consideration is given to the efficiency of a class of black hole heat engines that perform mechanical work via the pdV terms present in the First Law of extended gravitational thermodynamics. It is noted that, when the engine cycle is a rectangle with sides parallel to the (p,V) axes, the efficiency can be written simply in terms of the mass of the black hole evaluated at the corners. Since an arbitrary cycle can be approximated to any desired accuracy by a tiling of rectangles, a general geometrical algorithm for computing the efficiency of such a cycle follows. Finally, amore » simple generalization of the algorithm renders it applicable to broader classes of heat engine, even beyond the black hole context.« less

Modelling the degradation and elastic properties of poly(lactic-co-glycolic acid) films and regular open-cell tissue engineering scaffolds.

PubMed

Shirazi, Reyhaneh Neghabat; Ronan, William; Rochev, Yury; McHugh, Peter

2016-02-01

Scaffolding plays a critical rule in tissue engineering and an appropriate degradation rate and sufficient mechanical integrity are required during degradation and healing of tissue. This paper presents a computational investigation of the molecular weight degradation and the mechanical performance of poly(lactic-co-glycolic acid) (PLGA) films and tissue engineering scaffolds. A reaction-diffusion model which predicts the degradation behaviour is coupled with an entropy-based mechanical model which relates Young׳s modulus and the molecular weight. The model parameters are determined based on experimental data for in-vitro degradation of a PLGA film. Microstructural models of three different scaffold architectures are used to investigate the degradation and mechanical behaviour of each scaffold. Although the architecture of the scaffold does not have a significant influence on the degradation rate, it determines the initial stiffness of the scaffold. It is revealed that the size of the scaffold strut controls the degradation rate and the mechanical collapse. A critical length scale due to competition between diffusion of degradation products and autocatalytic degradation is determined to be in the range 2-100μm. Below this range, slower homogenous degradation occurs; however, for larger samples monomers are trapped inside the sample and faster autocatalytic degradation occurs. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of coupling approaches for thermomechanical simulations

DOE PAGES

Novascone, S. R.; Spencer, B. W.; Hales, J. D.; ...

2015-08-10

Many problems of interest, particularly in the nuclear engineering field, involve coupling between the thermal and mechanical response of an engineered system. The strength of the two-way feedback between the thermal and mechanical solution fields can vary significantly depending on the problem. Contact problems exhibit a particularly high degree of two-way feedback between those fields. This paper describes and demonstrates the application of a flexible simulation environment that permits the solution of coupled physics problems using either a tightly coupled approach or a loosely coupled approach. In the tight coupling approach, Newton iterations include the coupling effects between all physics,more » while in the loosely coupled approach, the individual physics models are solved independently, and fixed-point iterations are performed until the coupled system is converged. These approaches are applied to simple demonstration problems and to realistic nuclear engineering applications. The demonstration problems consist of single and multi-domain thermomechanics with and without thermal and mechanical contact. Simulations of a reactor pressure vessel under pressurized thermal shock conditions and a simulation of light water reactor fuel are also presented. Here, problems that include thermal and mechanical contact, such as the contact between the fuel and cladding in the fuel simulation, exhibit much stronger two-way feedback between the thermal and mechanical solutions, and as a result, are better solved using a tight coupling strategy.« less

Kh. A. Rakhmatulin's scientific legacy in the field of mechanics of deformable rigid bodies

NASA Astrophysics Data System (ADS)

Goldstein, R. V.; Dem'yanov, Yu. A.; Nikitin, L. V.; Smirnov, N. N.; Shemyakin, E. I.

2010-02-01

Kh. A. Rakhmatulin's scientific activity was aimed at solving the most important scientific and technical problems encountered by the country. Khalil Akhmetovich was a unique combination of a theorist and an experimenter, an engineer and an inventor, a talented teacher and a scientific research manager. He fruitfully worked in mechanics of deformable solids (the corresponding results are surveyed in the present paper) as well as in fluid mechanics (as described in detail in the journal [1] dedicated to his memory).

24 CFR 200.934 - User fee system for the technical suitability of products program.

Code of Federal Regulations, 2012 CFR

2012-04-01

... section establishes fee requirements for the issuance of Structural Engineering Bulletins (SEBs), Mechanical Engineering Bulletins (MEBs), Truss Connector Bulletins (TCBs), Area Letters of Acceptance (ALAs... Department. (i) With respect to Mechanical Engineering Bulletins (MEBs), Structural Engineering Bulletins...

24 CFR 200.934 - User fee system for the technical suitability of products program.

Code of Federal Regulations, 2013 CFR

2013-04-01

... section establishes fee requirements for the issuance of Structural Engineering Bulletins (SEBs), Mechanical Engineering Bulletins (MEBs), Truss Connector Bulletins (TCBs), Area Letters of Acceptance (ALAs... Department. (i) With respect to Mechanical Engineering Bulletins (MEBs), Structural Engineering Bulletins...

24 CFR 200.934 - User fee system for the technical suitability of products program.

Code of Federal Regulations, 2014 CFR

2014-04-01

... section establishes fee requirements for the issuance of Structural Engineering Bulletins (SEBs), Mechanical Engineering Bulletins (MEBs), Truss Connector Bulletins (TCBs), Area Letters of Acceptance (ALAs... Department. (i) With respect to Mechanical Engineering Bulletins (MEBs), Structural Engineering Bulletins...

24 CFR 200.934 - User fee system for the technical suitability of products program.

Code of Federal Regulations, 2011 CFR

2011-04-01

... section establishes fee requirements for the issuance of Structural Engineering Bulletins (SEBs), Mechanical Engineering Bulletins (MEBs), Truss Connector Bulletins (TCBs), Area Letters of Acceptance (ALAs... Department. (i) With respect to Mechanical Engineering Bulletins (MEBs), Structural Engineering Bulletins...

Natural tooth intrusion and reversal in implant-assisted prosthesis: evidence of and a hypothesis for the occurrence.

PubMed

Sheets, C G; Earthmann, J C

1993-12-01

Based on clinical observation, a hypothesis of the mechanism of intrusion of natural teeth in an implant-assisted prosthesis is suggested. Engineering principles are presented that establish an energy absorption model as it relates to the implant-assisted prosthesis. In addition, in the course of patient treatment it has been discovered that the intrusion of natural teeth can be reversed. Patient histories that demonstrate intrusion reversal are reviewed. The possible mechanisms for the intrusion/reversal phenomenon are presented and preventative recommendations are given.

Bending-induced folding, an actuation mechanism for plant reconfiguration.

NASA Astrophysics Data System (ADS)

Terwagne, Denis; Segers, JéRéMy; trioS. lab-Soft Structures; Surfaces Lab Team

Inspired by the sophisticated mechanism of the opening and closing of the ice seed plant valves (Aizoaceae), we present a simple model experiment of this mechanism based on an origami folding. By imposing a curvature to one of the plate connected to a fold designed along a curved path, we actuate its opening and closing. The imposed curvature induces inner mechanical constraints that give us a precise control of the deflection angle, which ultimately leads the fold to close completely. In this talk, we will present an analysis and characterization of this mechanism as a function of the geometrical and mechanical parameters of the system. From these insights, we will show how to build origami pliers with tunable mechanical properties. Possible out comings that might arise in various fields, ranging from deployable engineered structure to soft robotics and medical devices, are discussed. DT and JS thank the Belgian national science foundation F.R.S-FNRS for funding.

Super Turbocharging the Direct Injection Diesel engine

NASA Astrophysics Data System (ADS)

Boretti, Albert

2018-03-01

The steady operation of a turbocharged diesel direct injection (TDI) engine featuring a variable speed ratio mechanism linking the turbocharger shaft to the crankshaft is modelled in the present study. Key parameters of the variable speed ratio mechanism are range of speed ratios, efficiency and inertia, in addition to the ability to control relative speed and flow of power. The device receives energy from, or delivers energy to, the crankshaft or the turbocharger. In addition to the pistons of the internal combustion engine (ICE), also the turbocharger thus contributes to the total mechanical power output of the engine. The energy supply from the crankshaft is mostly needed during sharp accelerations to avoid turbo-lag, and to boost torque at low speeds. At low speeds, the maximum torque is drastically improved, radically expanding the load range. Additionally, moving closer to the points of operation of a balanced turbocharger, it is also possible to improve both the efficiency η, defined as the ratio of the piston crankshaft power to the fuel flow power, and the total efficiency η*, defined as the ratio of piston crankshaft power augmented of the power from the turbocharger shaft to the fuel flow power, even if of a minimal extent. The energy supply to the crankshaft is possible mostly at high speeds and high loads, where otherwise the turbine could have been waste gated, and during decelerations. The use of the energy at the turbine otherwise waste gated translates in improvements of the total fuel conversion efficiency η* more than the efficiency η. Much smaller improvements are obtained for the maximum torque, yet again moving closer to the points of operation of a balanced turbocharger. Adopting a much larger turbocharger (target displacement x speed 30% larger than a conventional turbocharger), better torque outputs and fuel conversion efficiencies η* and η are possible at every speed vs. the engine with a smaller, balanced turbocharger. This result motivates further studies of the mechanism that may considerably benefit traditional powertrains based on diesel engines.

Standardized Curriculum for Outboard Marine Engine Mechanics.

ERIC Educational Resources Information Center

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

This curriculum guide for outboard marine engine mechanics was developed by the state of Mississippi to standardize vocational education course titles and core contents. The objectives contained in this document are common to all outboard marine engine mechanics programs in the state. The guide contains objectives for outboard marine engine…

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

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Mechanical engine order telegraph systems; operation. 113.35-13 Section 113.35-13 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED...-13 Mechanical engine order telegraph systems; operation. If more than one transmitter operates a...

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

Federal Register 2010, 2011, 2012, 2013, 2014

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...

Dr. Johney Green Jr. - Associate Laboratory Director for Mechanical and

Science.gov Websites

Thermal Engineering Sciences | NREL Dr. Johney Green Jr. - Associate Laboratory Director for Mechanical and Thermal Engineering Sciences Dr. Johney Green Jr. - Associate Laboratory Director for Mechanical and Thermal Engineering Sciences A photo of Johney Green In his role, Johney Green oversees early

Engineered Three-Dimensional Cardiac Fibrotic Tissue to Study Fibrotic Remodeling

PubMed Central

Sadeghi, Amir Hossein; Shin, Su Ryon; Deddens, Janine C.; Fratta, Giuseppe; Mandla, Serena; Yazdi, Iman K.; Prakash, Gyan; Antona, Silvia; Demarchi, Danilo; Buijsrogge, Marc P.; Sluijter, Joost P.G.; Hjortnaes, Jesper

2017-01-01

Activation of cardiac fibroblasts (CF) into myofibroblasts is considered to play an essential role in cardiac remodeling and fibrosis. A limiting factor in studying this process is the spontaneous activation of CFs when cultured on two-dimensional (2D) culture plates. Here, a simplified 3D hydrogel platform of contractile cardiac tissue, stimulated by transforming growth factor-β1 (TGF-β1), is presented to recapitulate a fibrogenic micro-environment. It was hypothesized that the quiescent state of CFs can be maintained by mimicking the mechanical stiffness of native heart tissue. To test this hypothesis, a 3D cell culture model consisting of cardiomyocytes and CFs encapsulated within mechanically engineered gelatin methacryloyl (GelMA) hydrogel, was developed. The study shows that CFs maintain their quiescent phenotype in mechanically tuned hydrogels. Additionally, treatment with a beta-adrenergic agonist increased beating frequency, demonstrating physiologic-like behavior of the heart constructs. Subsequently, quiescent CFs within the constructs were activated by the exogenous addition of TGF-β1. The expression of fibrotic protein markers (and the functional changes in mechanical stiffness) in the fibrotic-like tissues were analyzed to validate the model. Overall, this 3D engineered culture model of contractile cardiac tissue enabled controlled activation of CFs, demonstrating the usability of this platform to study fibrotic remodeling. PMID:28498548

Preparation and characterization of novel functionalized multiwalled carbon nanotubes/chitosan/β-Glycerophosphate scaffolds for bone tissue engineering.

PubMed

Gholizadeh, Shayan; Moztarzadeh, Fathollah; Haghighipour, Nooshin; Ghazizadeh, Leila; Baghbani, Fatemeh; Shokrgozar, Mohammad Ali; Allahyari, Zahra

2017-04-01

A major limitation in current tissue engineering scaffolds is that some of the most important characteristics of the intended tissue are ignored. As piezoelectricity and high mechanical strength are two of the most important characteristics of the bone tissue, carbon nanotubes are getting a lot of attention as a bone tissue scaffold component in recent years. In the present study, composite scaffolds comprised of functionalized Multiwalled Carbon Nanotubes (f-MWCNT), medium molecular weight chitosan and β-Glycerophosphate were fabricated and characterized. Biodegradability and mechanical tests indicate that while increasing f-MWCNT content can improve electrical conductivity and mechanical properties, there are some limitations for these increases, such as a decrease in mechanical properties and biodegradability in 1w/v% content of f-MWCNTs. Also, MTT cytotoxicity assay was conducted for the scaffolds and no significant cytotoxicity was observed. Increasing f-MWCNT content led to higher alkaline Phosphatase activity. The overall results show that composites with f-MWCNT content between 0.1w/v% and 0.5w/v% are the most suitable for bone tissue engineering application. Additionally, Preliminary cell electrical tests proved the efficiency of the prepared scaffolds for cell electrical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

A summary of NASA/Air Force Full Scale Engine Research programs using the F100 engine

NASA Technical Reports Server (NTRS)

Deskin, W. J.; Hurrell, H. G.

1979-01-01

This paper summarizes a joint NASA/Air Force Full Scale Engine Research (FSER) program conducted with the F100 engine during the period 1974 through 1979. The program mechanism is described and the F100 test vehicles utilized are illustrated. Technology items which have been addressed in the areas of swirl augmentation, flutter phenomenon, advanced electronic control logic theory, strain gage technology, and distortion sensitivity are identified and the associated test programs conducted at the NASA-Lewis Research Center are described. Results presented show that the FSER approach, which utilizes existing state-of-the-art engine hardware to evaluate advanced technology concepts and problem areas, can contribute a significant data base for future system applications. Aerodynamic phenomenon previously not considered by current design systems have been identified and incorporated into current industry design tools.

Martian (and Cold Region Lunar) Soil Mechanics Considerations

NASA Astrophysics Data System (ADS)

Chua, Koon Meng; Johnson, Stewart W.

1998-01-01

The exploration of Mars has generated a lot of interest in recent years. With the completion of the Pathfinder Mission and the commencement of detailed mapping by Mars Global Surveyor, the possibility of an inhabited outpost on the planet is becoming more realistic. In spite of the upbeat mood, human exploration of Mars is still many years in the future. Additionally, the earliest return of any martian soil samples will probably not be until 2008. So why the discussion about martian soil mechanics when there are no returned soil samples on hand to examine? In view of the lack of samples, the basis of this or any discussion at this time must necessarily be one that involves conjecture, but not without the advantage of our knowledge of regolith mechanics of the Moon and soil mechanics on Earth. The objective of this presentation/discussion is fourfold: (1) Review some basic engineering-related information about Mars that may be of interest to engineers, and scientists - including characteristics of water and C02 at low temperature; (2) review and bring together principles of soil mechanics pertinent to studying and predicting how martian soil may behave, including the morphology and physical characteristics of coarse-grained and fine-grained soils (including clays), the characteristics of collapsing soils, potentials and factors that affect migration of water in unfrozen and freezing/frozen soils, and the strength and stiffness characteristics of soils at cold temperatures; (3) discuss some preliminary results of engineering experiments performed with frozen lunar soil simulants, JSC-1, in the laboratory that show the response to temperature change with and without water, effects of water on the strength and stiffness at ambient and at below freezing temperatures; and (4) discuss engineering studies that could be performed prior to human exploration and engineering research to be performed alongside future scientific missions to that planet.

Damage-mitigating control of space propulsion systems for high performance and extended life

NASA Technical Reports Server (NTRS)

Ray, Asok; Wu, Min-Kuang; Dai, Xiaowen; Carpino, Marc; Lorenzo, Carl F.

1993-01-01

Calculations are presented showing that a substantial improvement in service life of a reusable rocket engine can be achieved by an insignificant reduction in the system dynamic performance. The paper introduces the concept of damage mitigation and formulates a continuous-time model of fatigue damage dynamics. For control of complex mechanical systems, damage prediction and damage mitigation are carried out based on the available sensory and operational information such that the plant can be inexpensively maintained and safely and efficiently steered under diverse operating conditions. The results of simulation experiments are presented for transient operations of a reusable rocket engine.

New Approaches to Multidisciplinary Design and Optimization

NASA Technical Reports Server (NTRS)

Schrage, D. P.; Craig, J. I.; Fulton, R. E.; Mistree, F.

1995-01-01

Research under the subject grant is being carried out in a jointly coordinated effort within three laboratories in the School of Aerospace Engineering and the George Woodruff School of Mechanical Engineering. The objectives and results for Year 2 of the research program are summarized. The "Objectives" and "Expected Significance" are taken directly from the Year 2 Proposal presented in October 1994, and "Results" summarize the what has been accomplished this year. A discussion of these results is provided in the following sections. A listing of papers, presentations and reports that acknowledge grant support, either in part or in whole, and that were prepared during this period is provided in an attachment.

Advanced Environmental Barrier Coating Development for SiC-SiC Ceramic Matrix Composite Components

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Harder, Bryan; Bhatt, Ramakrishna; Kiser, Doug; Wiesner, Valerie L.

2016-01-01

This presentation reviews the NASA advanced environmental barrier coating (EBC) system development for SiCSiC Ceramic Matrix Composite (CMC) components for next generation turbine engines. The emphasis has been placed on the current design challenges of the 2700F environmental barrier coatings; coating processing and integration with SiCSiC CMCs and component systems; and performance evaluation and demonstration of EBC-CMC systems. This presentation also highlights the EBC-CMC system temperature capability and durability improvements through advanced compositions and architecture designs, as shown in recent simulated engine high heat flux, combustion environment, in conjunction with mechanical creep and fatigue loading testing conditions.

The role of mechanical loading in ligament tissue engineering.

PubMed

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.

Rate-programming of nano-particulate delivery systems for smart bioactive scaffolds in tissue engineering.

PubMed

Izadifar, Mohammad; Haddadi, Azita; Chen, Xiongbiao; Kelly, Michael E

2015-01-09

Development of smart bioactive scaffolds is of importance in tissue engineering, where cell proliferation, differentiation and migration within scaffolds can be regulated by the interactions between cells and scaffold through the use of growth factors (GFs) and extra cellular matrix peptides. One challenge in this area is to spatiotemporally control the dose, sequence and profile of release of GFs so as to regulate cellular fates during tissue regeneration. This challenge would be addressed by rate-programming of nano-particulate delivery systems, where the release of GFs via polymeric nanoparticles is controlled by means of the methods of, such as externally-controlled and physicochemically/architecturally-modulated so as to mimic the profile of physiological GFs. Identifying and understanding such factors as the desired release profiles, mechanisms of release, physicochemical characteristics of polymeric nanoparticles, and externally-triggering stimuli are essential for designing and optimizing such delivery systems. This review surveys the recent studies on the desired release profiles of GFs in various tissue engineering applications, elucidates the major release mechanisms and critical factors affecting release profiles, and overviews the role played by the mathematical models for optimizing nano-particulate delivery systems. Potentials of stimuli responsive nanoparticles for spatiotemporal control of GF release are also presented, along with the recent advances in strategies for spatiotemporal control of GF delivery within tissue engineered scaffolds. The recommendation for the future studies to overcome challenges for developing sophisticated particulate delivery systems in tissue engineering is discussed prior to the presentation of conclusions drawn from this paper.

Simulated effect on the compressive and shear mechanical properties of bionic integrated honeycomb plates.

PubMed

He, Chenglin; Chen, Jinxiang; Wu, Zhishen; Xie, Juan; Zu, Qiao; Lu, Yun

2015-05-01

Honeycomb plates can be applied in many fields, including furniture manufacturing, mechanical engineering, civil engineering, transportation and aerospace. In the present study, we discuss the simulated effect on the mechanical properties of bionic integrated honeycomb plates by investigating the compressive and shear failure modes and the mechanical properties of trabeculae reinforced by long or short fibers. The results indicate that the simulated effect represents approximately 80% and 70% of the compressive and shear strengths, respectively. Compared with existing bionic samples, the mass-specific strength was significantly improved. Therefore, this integrated honeycomb technology remains the most effective method for the trial manufacturing of bionic integrated honeycomb plates. The simulated effect of the compressive rigidity is approximately 85%. The short-fiber trabeculae have an advantage over the long-fiber trabeculae in terms of shear rigidity, which provides new evidence for the application of integrated bionic honeycomb plates. Copyright © 2015 Elsevier B.V. All rights reserved.

Carbon Nanotube Composites: Strongest Engineering Material Ever?

NASA Technical Reports Server (NTRS)

Mayeaux, Brian; Nikolaev, Pavel; Proft, William; Nicholson, Leonard S. (Technical Monitor)

1999-01-01

The primary goal of the carbon nanotube project at Johnson Space Center (JSC) is to fabricate structural materials with a much higher strength-to-weight ratio than any engineered material today, Single-wall nanotubes present extraordinary mechanical properties along with new challenges for materials processing. Our project includes nanotube production, characterization, purification, and incorporation into applications studies. Now is the time to move from studying individual nanotubes to applications work. Current research at JSC focuses on structural polymeric materials to attempt to lower the weight of spacecraft necessary for interplanetary missions. These nanoscale fibers present unique new challenges to composites engineers. Preliminary studies show good nanotube dispersion and wetting by the epoxy materials. Results of tensile strength tests will also be reported. Other applications of nanotubes are also of interest for energy storage, gas storage, nanoelectronics, field emission, and biomedical uses.

46 CFR 12.607 - Requirements to qualify for an STCW endorsement as rating as able seafarer-engine.

Code of Federal Regulations, 2014 CFR

2014-10-01

... mechanic, or engineman in the engine department, or as an RFPEW for a period of not less than 12 months... Engineman None. Deck Engine Mechanic None. Electrician 6 months.1 Refrigerating Engineer 6 months.1 Pumpman...

Two-Year ET Programs: Essential Topics and Levels of Proficiency.

ERIC Educational Resources Information Center

Gourley, Frank A., Jr.

1990-01-01

Reports the results of a survey of graduates, employers, and instructors of engineering technology programs for the essential topics in mechanical engineering technology, mechanical drafting/design technology, manufacturing engineering technology, and industrial engineering technology. Identifies the proficiency level suggested for classwork and…

Fabrication of ceramic substrate-reinforced and free forms

NASA Technical Reports Server (NTRS)

Quentmeyer, R. J.; Mcdonald, G.; Hendricks, R. C.

1985-01-01

Components fabricated of, or coated with, ceramics have lower parasitic cooling requirements. Techniques are discussed for fabricating thin-shell ceramic components and ceramic coatings for applications in rocket or jet engine environments. Thin ceramic shells with complex geometric forms involving convolutions and reentrant surfaces were fabricated by mandrel removal. Mandrel removal was combined with electroplating or plasma spraying and isostatic pressing to form a metal support for the ceramic. Rocket engine thrust chambers coated with 0.08 mm (3 mil) of ZrO2-8Y2O3 had no failures and a tenfold increase in engine life. Some measured mechanical properties of the plasma-sprayed ceramic are presented.

Investigation of the fundamentals of low-energy nanosecond pulse ignition: Final CRADA Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wallner, Thomas; Scarcelli, Riccardo; Zhang, Anqi

A detailed investigation of the fundamentals of low-energy nanosecond pulse ignition was performed with the objective to overcome the barrier presented by limited knowledge and characterization of nonequilibrium plasma ignition for realistic internal combustion engine applications (be it in the automotive or power generation field) and shed light on the mechanisms which improve the performance of the advanced TPS ignition system compared to conventional state-of-the-art hardware. Three main tasks of the research included experimental evaluation on a single-cylinder automotive gasoline engine, experimental evaluation on a single-cylinder stationary natural gas engine and energy quantification using x-ray diagnostics.

Cartilage tissue engineering: recent advances and perspectives from gene regulation/therapy.

PubMed

Li, Kuei-Chang; Hu, Yu-Chen

2015-05-01

Diseases in articular cartilages affect millions of people. Despite the relatively simple biochemical and cellular composition of articular cartilages, the self-repair ability of cartilage is limited. Successful cartilage tissue engineering requires intricately coordinated interactions between matrerials, cells, biological factors, and phycial/mechanical factors, and still faces a multitude of challenges. This article presents an overview of the cartilage biology, current treatments, recent advances in the materials, biological factors, and cells used in cartilage tissue engineering/regeneration, with strong emphasis on the perspectives of gene regulation (e.g., microRNA) and gene therapy. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Practical Possibilities of High-Altitude Flight with Exhaust-Gas Turbines in Connection with Spark Ignition Engines Comparative Thermodynamic and Flight Mechanical Investigations

NASA Technical Reports Server (NTRS)

Weise, A.

1947-01-01

As a means of preparing for high-altitude flight with spark-ignition engines in conjunction with exhaust-gas turbosuperchargers, various methods of modifying the exhaust-gas temperatures, which are initially higher than a turbine can withstand are mathematically compared. The thermodynamic results first obtained are then examined with respect to the effect on flight speed, climbing speed, ceiling, economy, and cruising range. The results are so presented in a generalized form that they may be applied to every appropriate type of aircraft design and a comparison with the supercharged engine without exhaust-gas turbine can be made.

Energy efficient engine: Turbine intermediate case and low-pressure turbine component test hardware detailed design report

NASA Technical Reports Server (NTRS)

Leach, K.; Thulin, R. D.; Howe, D. C.

1982-01-01

A four stage, low pressure turbine component has been designed to power the fan and low pressure compressor system in the Energy Efficient Engine. Designs for a turbine intermediate case and an exit guide vane assembly also have been established. The components incorporate numerous technology features to enhance efficiency, durability, and performance retention. These designs reflect a positive step towards improving engine fuel efficiency on a component level. The aerodynamic and thermal/mechanical designs of the intermediate case and low pressure turbine components are presented and described. An overview of the predicted performance of the various component designs is given.

Engineering of arteries in vitro

PubMed Central

Huang, Angela H.; Niklason, Laura E.

2014-01-01

This review will focus on two elements that are essential for functional arterial regeneration in vitro: the mechanical environment and the bioreactors used for tissue growth. The importance of the mechanical environment to embryological development, vascular functionality, and vascular graft regeneration will be discussed. Bioreactors generate mechanical stimuli to simulate the biomechanical environment of the arterial system. This system has been used to reconstruct arterial grafts with appropriate mechanical strength for implantation by controlling the chemical and mechanical environments in which the grafts are grown. Bioreactors are powerful tools to study the effect of mechanical stimuli on extracellular matrix (ECM) architecture and the mechanical properties of engineered vessels. Hence biomimetic systems enable us to optimize chemo-biomechanical culture conditions to regenerate engineered vessels with physiological properties similar to those of native arterial vessels. In addition, this review will introduce and examine various approaches and techniques that have been used to engineer biologically-based vascular grafts, including collagen-based grafts, fibrin-gel grafts, cell sheet engineering, biodegradable polymers, and decellularization of native vessels. PMID:24399290

Lyophilized Silk Sponges: A Versatile Biomaterial Platform for Soft Tissue Engineering

PubMed Central

2015-01-01

We present a silk biomaterial platform with highly tunable mechanical and degradation properties for engineering and regeneration of soft tissues such as, skin, adipose, and neural tissue, with elasticity properties in the kilopascal range. Lyophilized silk sponges were prepared under different process conditions and the effect of silk molecular weight, concentration and crystallinity on 3D scaffold formation, structural integrity, morphology, mechanical and degradation properties, and cell interactions in vitro and in vivo were studied. Tuning the molecular weight distribution (via degumming time) of silk allowed the formation of stable, highly porous, 3D scaffolds that held form with silk concentrations as low as 0.5% wt/v. Mechanical properties were a function of silk concentration and scaffold degradation was driven by beta-sheet content. Lyophilized silk sponges supported the adhesion of mesenchymal stem cells throughout 3D scaffolds, cell proliferation in vitro, and cell infiltration and scaffold remodeling when implanted subcutaneously in vivo. PMID:25984573

Reverse engineering the cooperative machinery of human hemoglobin.

PubMed

Ren, Zhong

2013-01-01

Hemoglobin transports molecular oxygen from the lungs to all human tissues for cellular respiration. Its α2β2 tetrameric assembly undergoes cooperative binding and releasing of oxygen for superior efficiency and responsiveness. Over past decades, hundreds of hemoglobin structures were determined under a wide range of conditions for investigation of molecular mechanism of cooperativity. Based on a joint analysis of hemoglobin structures in the Protein Data Bank (Ren, companion article), here I present a reverse engineering approach to elucidate how two subunits within each dimer reciprocate identical motions that achieves intradimer cooperativity, how ligand-induced structural signals from two subunits are integrated to drive quaternary rotation, and how the structural environment at the oxygen binding sites alter their binding affinity. This mechanical model reveals the intricate design that achieves the cooperative mechanism and has previously been masked by inconsistent structural fluctuations. A number of competing theories on hemoglobin cooperativity and broader protein allostery are reconciled and unified.

Engineering cells for cell culture bioprocessing--physiological fundamentals.

PubMed

Seth, Gargi; Hossler, Patrick; Yee, Joon Chong; Hu, Wei-Shou

2006-01-01

In the past decade, we have witnessed a tremendous increase in the number of mammalian cell-derived therapeutic proteins with clinical applications. The success of making these life-saving biologics available to the public is partly due to engineering efforts to enhance process efficiency. To further improve productivity, much effort has been devoted to developing metabolically engineered producing cells, which possess characteristics favorable for large-scale bioprocessing. In this article we discuss the fundamental physiological basis for cell engineering. Different facets of cellular mechanisms, including metabolism, protein processing, and the balancing pathways of cell growth and apoptosis, contribute to the complex traits of favorable growth and production characteristics. We present our assessment of the current state of the art by surveying efforts that have already been undertaken in engineering cells for a more robust process. The concept of physiological homeostasis as a key determinant and its implications on cell engineering is emphasized. Integrating the physiological perspective with cell culture engineering will facilitate attainment of dream cells with superlative characteristics.

Direct Numerical Simulations of Autoignition in Stratified Dimethyl-ether (DME)/Air Turbulent Mixtures

DOE PAGES

Bansal, Gaurav; Mascarenhas, Ajith; Chen, Jacqueline H.

2014-10-01

In our paper, two- and three-dimensional direct numerical simulations (DNS) of autoignition phenomena in stratified dimethyl-ether (DME)/air turbulent mixtures are performed. A reduced DME oxidation mechanism, which was obtained using rigorous mathematical reduction and stiffness removal procedure from a detailed DME mechanism with 55 species, is used in the present DNS. The reduced DME mechanism consists of 30 chemical species. This study investigates the fundamental aspects of turbulence-mixing-autoignition interaction occurring in homogeneous charge compression ignition (HCCI) engine environments. A homogeneous isotropic turbulence spectrum is used to initialize the velocity field in the domain. Moreover, the computational configuration corresponds to amore » constant volume combustion vessel with inert mass source terms added to the governing equations to mimic the pressure rise due to piston motion, as present in practical engines. DME autoignition is found to be a complex three-staged process; each stage corresponds to a distinct chemical kinetic pathway. The distinct role of turbulence and reaction in generating scalar gradients and hence promoting molecular transport processes are investigated. Then, by applying numerical diagnostic techniques, the different heat release modes present in the igniting mixture are identified. In particular, the contribution of homogeneous autoignition, spontaneous ignition front propagation, and premixed deflagration towards the total heat release are quantified.« less

Essays on the History of Rocketry and Astronautics: Proceedings of the Third through the Sixth History Symposia of the International Academy of Astronautics, volume 1

NASA Technical Reports Server (NTRS)

Hall, R. C. (Editor)

1977-01-01

This two volume publication presents the proceedings of the third through sixth history symposia of the International Academy of Astronautics. Thirty-nine papers are divided into four categories: (1) Early Solid Propellant Rocketry; (2) Rocketry and Astronautics: Concepts, Theory, and Analyses after 1880; (3) The Development of Liquid and Solid Propellant Rockets from 1880 to 1945; and (4) Rocketry and Astronautics after 1945. Categories 1 and 2 will be found in volume 1 and the remainder in volume 2. Among other diciplines, Rocketry and Astronautics encompasses the physical and engineering sciences including fluid mechanics, thermodynamics, vibration theory, structural mechanics, and celestial mechanics. Papers presented in these two volumes range from those of empirical experimenters who used the time-honored cut and try methods to scientists wielding theoretical principles. The work traces the coupling of the physical and engineering sciences, industrial advances, and state support that produced the awesome progress in rocketry and astronautics for the most part within living memory. The proceedings of the four symposia present in these two volumes contain information on the work of leading investigators and their associates carried out in the first two-thirds of the twentieth century.

First Year Experiences in School of Mechanical Engineering Kanazawa University

NASA Astrophysics Data System (ADS)

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.

Engineering antigen-specific immunological tolerance.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kontos, Stephan; Grimm, Alizee J.; Hubbell, Jeffrey A.

2015-05-01

Unwanted immunity develops in response to many protein drugs, in autoimmunity, in allergy, and in transplantation. Approaches to induce immunological tolerance aim to either prevent these responses or reverse them after they have already taken place. We present here recent developments in approaches, based on engineered peptides, proteins and biomaterials, that harness mechanisms of peripheral tolerance both prophylactically and therapeutically to induce antigenspecific immunological tolerance. These mechanisms are based on responses of B and T lymphocytes to other cells in their immune environment that result in cellular deletion or ignorance to particular antigens, or in development of active immune regulatorymore » responses. Several of these approaches are moving toward clinical development, and some are already in early stages of clinical testing.« less

Outsourcing neural active control to passive composite mechanics: a tissue engineered cyborg ray

NASA Astrophysics Data System (ADS)

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".

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

Code of Federal Regulations, 2010 CFR

2010-10-01

... vehicles, mechanical equipment containing internal combustion engines, and battery powered vehicles or... equipment containing internal combustion engines, and battery powered vehicles or equipment. (a... internal combustion engine, or a battery powered vehicle or equipment is subject to the requirements of...

Table-Top Robotics for Engineering Design

ERIC Educational Resources Information Center

Wilczynski, Vincent; Dixon, Gregg; Ford, Eric

2005-01-01

The Mechanical Engineering Section at the U.S. Coast Guard Academy has developed a comprehensive activity based course to introduce second year students to mechanical engineering design. The culminating design activity for the course requires students to design, construct and test robotic devices that complete engineering challenges. Teams of…

Shawn Sheng | NREL

Science.gov Websites

experience includes mechanical and electrical system modeling and analysis, data sensing and sensor placement . Education Ph.D. in Mechanical Engineering, University of Massachusetts at Amherst; M.S. in Electrical Engineering, Institute of Electrical Engineering, Chinese Academy of Sciences; B.S. in Electrical Engineering

Fast nastic motion of plants and bioinspired structures

PubMed Central

Guo, Q.; Dai, E.; Han, X.; Xie, S.; Chao, E.; Chen, Z.

2015-01-01

The capability to sense and respond to external mechanical stimuli at various timescales is essential to many physiological aspects in plants, including self-protection, intake of nutrients and reproduction. Remarkably, some plants have evolved the ability to react to mechanical stimuli within a few seconds despite a lack of muscles and nerves. The fast movements of plants in response to mechanical stimuli have long captured the curiosity of scientists and engineers, but the mechanisms behind these rapid thigmonastic movements are still not understood completely. In this article, we provide an overview of such thigmonastic movements in several representative plants, including Dionaea, Utricularia, Aldrovanda, Drosera and Mimosa. In addition, we review a series of studies that present biomimetic structures inspired by fast-moving plants. We hope that this article will shed light on the current status of research on the fast movements of plants and bioinspired structures and also promote interdisciplinary studies on both the fundamental mechanisms of plants' fast movements and biomimetic structures for engineering applications, such as artificial muscles, multi-stable structures and bioinspired robots. PMID:26354828

Biofluid Mechanics Education at U Michigan

NASA Astrophysics Data System (ADS)

Grotberg, James

2007-11-01

At the University of Michigan, biofluid mechanics is taught in the Department of Biomedical Engineering with cross-listing in Mechanical Engineering. The course has evolved over 25 years and serves advanced undergraduates and graduate students. The course description is as follows: BiomedE/MechE 476 Biofluid Mechanics. CATALOG DESCRIPTION: This is an intermediate level fluid mechanics course which uses examples from biotechnology processes and physiologic applications including cellular, cardiovascular, respiratory, ocular, renal, orthopedic, and gastrointestinal systems. COURSE TOPICS: 1. Dimensional analysis (gastrointestinal, renal) 2. Approximation methods, numerical methods (biotechnology, respiratory) 3. Particle kinematics in Eulerian and Lagrangian references frames (biotechnology, respiratory) 4. Conservation of mass and momentum 5. Constitutive equations (blood, mucus) 6. Kinematic and stress boundary conditions: rigid, flexible, porous (cardio-pulmonary, cellular) 7. Surface tension phenomena (pulmonary, ocular) 8. Flow and wave propagation in flexible tubes (cardio-pulmonary) 9. Oscillatory and pulsatile flows (cardio-pulmonary, orthopedic) 10. High Reynolds number flows (cardio-pulmonary) 11. Low Reynolds number flows (biotechnology, cellular, vascular) 12. Lubrication theory (vascular, orthopedic) 13. Flow in poroelastic media (orthopedic, pulmonary, ocular) 14. Video presentations of laboratory experiments.

Fast nastic motion of plants and bioinspired structures.

PubMed

Guo, Q; Dai, E; Han, X; Xie, S; Chao, E; Chen, Z

2015-09-06

The capability to sense and respond to external mechanical stimuli at various timescales is essential to many physiological aspects in plants, including self-protection, intake of nutrients and reproduction. Remarkably, some plants have evolved the ability to react to mechanical stimuli within a few seconds despite a lack of muscles and nerves. The fast movements of plants in response to mechanical stimuli have long captured the curiosity of scientists and engineers, but the mechanisms behind these rapid thigmonastic movements are still not understood completely. In this article, we provide an overview of such thigmonastic movements in several representative plants, including Dionaea, Utricularia, Aldrovanda, Drosera and Mimosa. In addition, we review a series of studies that present biomimetic structures inspired by fast-moving plants. We hope that this article will shed light on the current status of research on the fast movements of plants and bioinspired structures and also promote interdisciplinary studies on both the fundamental mechanisms of plants' fast movements and biomimetic structures for engineering applications, such as artificial muscles, multi-stable structures and bioinspired robots. © 2015 The Author(s).

Laser engines operating by resonance absorption.

PubMed

Garbuny, M; Pechersky, M J

1976-05-01

The coherence properties and power levels of lasers available at present lend themselves to the remote operation of mechanical engines by resonance absorption in a working gas. Laser radiation is capable of producing extremely high temperatures in a gas. Limits to the achievable temperatures in the working gas of an engine are imposed by the solid walls and by loss of resonance absorption due to thermal saturation, bleaching, and dissociation. However, it is shown that by proper control of the laser beam in space, time, and frequency, as well as by choice of the absorbing gas, these limits are to a great extent removed so that very high temperatures are indeed attainable. The working gas is largely monatomic, preferably helium with the addition of a few volume percent of an absorber. Such a gas mixture, internally heated, permits an optimization of the expansion ratio, with resulting thermal efficiencies and work ratios, not achievable in conventional engines. A relationship between thermal efficiency and work ratio is derived that is quite general for the optimization condition. The performance of laser piston engines, turbines, and the Stirling cycle based on these principles is discussed and compared with conventional engine operation. Finally, a brief discussion is devoted to the possibility and concepts for the direct conversion of selective vibrational or electronic excitation into mechanical work, bypassing the translational degrees of freedom.

Australian Apprentice & Trainee Statistics: Mechanical Engineering and Fabrication Trades, 1995-1999. Australian Vocational Education & Training.

ERIC Educational Resources Information Center

National Centre for Vocational Education Research, Leabrook (Australia).

Statistics regarding Australians participating in apprenticeships and traineeships in the mechanical engineering and fabrication trades in 1995-1999 were reviewed to provide an indication of where skill shortages may be occurring or will likely occur in relation to the following occupations: mechanical engineering trades; fabrication engineering…

MECHANICAL STRENGTH RESPONSES OF POLED LEAD ZIRCONATE TITANATE UNDER EXTREME ELECTRIC FIELD AND VARIOUS TEMPERATURE CONDITIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Hong; Matsunaga, Tadashi; Zhang, Kewei

PZT (lead zirconate titanate), particularly PZT-5A, is used in a variety of critical actuation and sensing systems because of its high Curie temperature and large piezoelectric coefficients. However, PZT is susceptible to mechanical failure. The evaluation of the mechanical strength of the material under the target working conditions is very important. This study presents part of the recent experimental developments in mechanical testing and evaluation of PZT materials at Oak Ridge National Laboratory. Ball-on-ring and four-point bending testing setups were used, with modifications made to account for testing requirements from high-level electric field and elevated temperature. The poled PZT-5A ormore » equivalent material was tested under various specimen and testing conditions. The parameters of the distribution of strengths (characteristic strength and Weibull modulus) are discussed in relation to the testing conditions. Fractographic results based on scanning electron microscopy are also presented and discussed. The related data can serve as input for the design of piezoceramic devices, not only those used in energy systems like fuel injectors in heavy-duty diesel engines, but also those used in structural health monitoring, energy harvesting, and other critical systems in aerospace and civil engineering.« less

Simplified jet fuel reaction mechanism for lean burn combustion application

NASA Technical Reports Server (NTRS)

Lee, Chi-Ming; Kundu, Krishna; Ghorashi, Bahman

1993-01-01

Successful modeling of combustion and emissions in gas turbine engine combustors requires an adequate description of the reaction mechanism. Detailed mechanisms contain a large number of chemical species participating simultaneously in many elementary kinetic steps. Current computational fluid dynamic models must include fuel vaporization, fuel-air mixing, chemical reactions, and complicated boundary geometries. A five-step Jet-A fuel mechanism which involves pyrolysis and subsequent oxidation of paraffin and aromatic compounds is presented. This mechanism is verified by comparing with Jet-A fuel ignition delay time experimental data, and species concentrations obtained from flametube experiments. This five-step mechanism appears to be better than the current one- and two-step mechanisms.

Selection of software for mechanical engineering undergraduates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheah, C. T.; Yin, C. S.; Halim, T.

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.

Training mechanical engineering students to utilize biological inspiration during product development.

PubMed

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.

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

PubMed

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.

Photo-cross-linkable methacrylated gelatin and hydroxyapatite hybrid hydrogel for modularly engineering biomimetic osteon.

PubMed

Zuo, Yicong; Liu, Xiaolu; Wei, Dan; Sun, Jing; Xiao, Wenqian; Zhao, Huan; Guo, Likun; Wei, Qingrong; Fan, Hongsong; Zhang, Xingdong

2015-05-20

Modular tissue engineering holds great potential in regenerating natural complex tissues by engineering three-dimensional modular scaffolds with predefined geometry and biological characters. In modular tissue-like construction, a scaffold with an appropriate mechanical rigidity for assembling fabrication and high biocompatibility for cell survival is the key to the successful bioconstruction. In this work, a series of composite hydrogels (GH0, GH1, GH2, and GH3) based on a combination of methacrylated gelatin (GelMA) and hydroxyapatite (HA) was exploited to enhance hydrogel mechanical rigidity and promote cell functional expression for osteon biofabrication. These composite hydrogels presented a lower swelling ratio, higher mechanical moduli, and better biocompatibility when compared to the pure GelMA hydrogel. Furthermore, on the basis of the composite hydrogel and photolithograph technology, we successfully constructed an osteon-like concentric double-ring structure in which the inner ring encapsulating human umbilical vascular endothelial cells (HUVECs) was designed to imitate blood vessel tubule while the outer ring encapsulating human osteoblast-like cells (MG63s) acts as part of bone. During the coculture period, MG63s and HUVECs exhibited not only satisfying growth status but also the enhanced genic expression of osteogenesis-related and angiogenesis-related differentiations. These results demonstrate this GelMA-HA composite hydrogel system is promising for modular tissue engineering.

The design and development of a high-throughput magneto-mechanostimulation device for cartilage tissue engineering.

PubMed

Brady, Mariea A; Vaze, Reva; Amin, Harsh D; Overby, Darryl R; Ethier, C Ross

2014-02-01

To recapitulate the in vivo environment and create neo-organoids that replace lost or damaged tissue requires the engineering of devices, which provide appropriate biophysical cues. To date, bioreactors for cartilage tissue engineering have focused primarily on biomechanical stimulation. There is a significant need for improved devices for articular cartilage tissue engineering capable of simultaneously applying multiple biophysical (electrokinetic and mechanical) stimuli. We have developed a novel high-throughput magneto-mechanostimulation bioreactor, capable of applying static and time-varying magnetic fields, as well as multiple and independently adjustable mechanical loading regimens. The device consists of an array of 18 individual stations, each of which uses contactless magnetic actuation and has an integrated Hall Effect sensing system, enabling the real-time measurements of applied field, force, and construct thickness, and hence, the indirect measurement of construct mechanical properties. Validation tests showed precise measurements of thickness, within 14 μm of gold standard calliper measurements; further, applied force was measured to be within 0.04 N of desired force over a half hour dynamic loading, which was repeatable over a 3-week test period. Finally, construct material properties measured using the bioreactor were not significantly different (p=0.97) from those measured using a standard materials testing machine. We present a new method for articular cartilage-specific bioreactor design, integrating combinatorial magneto-mechanostimulation, which is very attractive from functional and cost viewpoints.

Challenge of biomechanics.

PubMed

Volokh, K Y

2013-06-01

The application of mechanics to biology--biomechanics--bears great challenges due to the intricacy of living things. Their dynamism, along with the complexity of their mechanical response (which in itself involves complex chemical, electrical, and thermal phenomena) makes it very difficult to correlate empirical data with theoretical models. This difficulty elevates the importance of useful biomechanical theories compared to other fields of engineering. Despite inherent imperfections of all theories, a well formulated theory is crucial in any field of science because it is the basis for interpreting observations. This is all-the-more vital, for instance, when diagnosing symptoms, or planning treatment to a disease. The notion of interpreting empirical data without theory is unscientific and unsound. This paper attempts to fortify the importance of biomechanics and invigorate research efforts for those engineers and mechanicians who are not yet involved in the field. It is not aimed here, however, to give an overview of biomechanics. Instead, three unsolved problems are formulated to challenge the readers. At the micro-scale, the problem of the structural organization and integrity of the living cell is presented. At the meso-scale, the enigma of fingerprint formation is discussed. At the macro-scale, the problem of predicting aneurysm ruptures is reviewed. It is aimed here to attract the attention of engineers and mechanicians to problems in biomechanics which, in the author's opinion, will dominate the development of engineering and mechanics in forthcoming years.

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

NASA Astrophysics Data System (ADS)

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.

Pullout of a Rigid Insert Adhesively Bonded to an Elastic Half Plane.

DTIC Science & Technology

1983-12-01

COMMAND UNITED STATES AIR FORCE C-= °84 02 13 071. C,, W % d 6 This document was prepared by the Department of Engineering Mechanics, USAF Academy Faculty...THOMAS E. KULLGREN, Lt Col, USAF Project Engineer /Scientist Professor and Acting Head, Department of Engineering Mechanics KENNETH E. SIEGETH Lt Col...Department of Engineering (Ifapphicable) Mechanics USAFA/DFEM 6c. ADDRESS (City. State and ZIP Code) 7b. ADDRESS (City, Slate and ZIP Code) USAF Academy

Cracking mechanism of shale cracks during fracturing

NASA Astrophysics Data System (ADS)

Zhao, X. J.; Zhan, Q.; Fan, H.; Zhao, H. B.; An, F. J.

2018-06-01

In this paper, we set up a model for calculating the shale fracture pressure on the basis of Huang’s model by the theory of elastic-plastic mechanics, rock mechanics and the application of the maximum tensile stress criterion, which takes into account such factors as the crustal stress field, chemical field, temperature field, tectonic stress field, the porosity of shale and seepage of drilling fluid and so on. Combined with the experimental data of field fracturing and the experimental results of three axis compression of shale core with different water contents, the results show that the error between the present study and the measured value is 3.85%, so the present study can provide technical support for drilling engineering.

Controlling Hydrogel Mechanics via Bio-Inspired Polymer-Nanoparticle Bond Dynamics.

PubMed

Li, Qiaochu; Barrett, Devin G; Messersmith, Phillip B; Holten-Andersen, Niels

2016-01-26

Interactions between polymer molecules and inorganic nanoparticles can play a dominant role in nanocomposite material mechanics, yet control of such interfacial interaction dynamics remains a significant challenge particularly in water. This study presents insights on how to engineer hydrogel material mechanics via nanoparticle interface-controlled cross-link dynamics. Inspired by the adhesive chemistry in mussel threads, we have incorporated iron oxide nanoparticles (Fe3O4 NPs) into a catechol-modified polymer network to obtain hydrogels cross-linked via reversible metal-coordination bonds at Fe3O4 NP surfaces. Unique material mechanics result from the supra-molecular cross-link structure dynamics in the gels; in contrast to the previously reported fluid-like dynamics of transient catechol-Fe(3+) cross-links, the catechol-Fe3O4 NP structures provide solid-like yet reversible hydrogel mechanics. The structurally controlled hierarchical mechanics presented here suggest how to develop hydrogels with remote-controlled self-healing dynamics.

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

NASA Astrophysics Data System (ADS)

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%.

An Educational Program of Mechatronics for Multidisciplinary Knowledge Acquisition

NASA Astrophysics Data System (ADS)

Watanuki, Keiichi; Kojima, Kazuyuki

Recently, as the technologies surrounding mechanical engineering have improved remarkably, the expectations for students who graduate from departments of mechanical engineering have increased. For example, in order to develop a mechatronics system, a student needs to integrate a wide variety of technologies, such as mechanical engineering, electrical and electronics engineering, and information technology. Therefore, from the perspective of educators, the current education system, which stresses expertizing each technology, should be replaced by an education system that stresses integrating multidisciplinary knowledge. In this paper, a trial education program for students of the department of mechanical engineering in our university, in which students are required to integrate multidisciplinary knowledge in order to develop a biologically-based robot, is described. Finally, the efficacy of the program is analyzed.

Gel spinning of silk tubes for tissue engineering

PubMed Central

Lovett, Michael; Cannizzaro, Christopher; Vunjak-Novakovic, Gordana; Kaplan, David L.

2011-01-01

Tubular vessels for tissue engineering are typically fabricated using a molding, dipping, or electrospinning technique. While these techniques provide some control over inner and outer diameters of the tube, they lack the ability to align the polymers or fibers of interest throughout the tube. This is an important aspect of biomaterial composite structure and function for mechanical and biological impact of tissue outcomes. We present a novel aqueous process system to spin tubes from biopolymers and proteins such as silk fibroin. Using silk as an example, this method of winding an aqueous solution around a reciprocating rotating mandrel offers substantial improvement in the control of the tube properties, specifically with regard to winding pattern, tube porosity, and composite features. Silk tube properties are further controlled via different post-spinning processing mechanisms such as methanol-treatment, air-drying, and lyophilization. This approach to tubular scaffold manufacture offers numerous tissue engineering applications such as complex composite biomaterial matrices, blood vessel grafts and nerve guides, among others. PMID:18801570

Degradation Mechanisms of an Advanced Jet Engine Service-Retired TBC Component

NASA Astrophysics Data System (ADS)

Wu, Rudder T.; Osawa, Makoto; Yokokawa, Tadaharu; Kawagishi, Kyoko; Harada, Hiroshi

Current use of TBCs is subjected to premature spallation failure mainly due to the formation of thermally grown oxides (TGOs). Although extensive research has been carried out to gain better understanding of the thermo - mechanical and -chemical characteristics of TBCs, laboratory-scale studies and simulation tests are often carried out in conditions significantly differed from the complex and extreme environment typically of a modern gas-turbine engine, thus, failed to truly model service conditions. In particular, the difference in oxygen partial pressure and the effects of contaminants present in the engine compartment have often been neglected. In this respect, an investigation is carried out to study the in-service degradation of an EB-PVD TBC coated nozzle-guide vane. Several modes of degradation were observed due to three factors: 1) presence of residual stresses induced by the thermal-expansion mismatches, 2) evolution of bond coat microstructure and subsequent formation of oxide spinels, 3) deposition of CMAS on the surface of TBC.

Deconvolution of the role of metal and pH in metal coordinating polymers

NASA Astrophysics Data System (ADS)

Cazzell, Seth; Holten-Andersen, Niels

Nature uses metal binding amino acids to engineer both mechanical properties and structural functionality. Some examples of this metal binding behavior can be found in both mussel foot protein and DNA binding protein. The mussel byssal thread contains reversible intermolecular protein-metal bonds, allowing it to withstand harsh intertidal environments. Zinc fingers form intramolecular protein-metal bonds to stabilize the tertiary structure of DNA binding proteins, allowing specific structural functionality. Inspired by both these metal-binding materials, we present mechanical and spectroscopic characterization of a model polymer system, designed to mimic this bonding. Through these studies, we are able to answer fundamental polymer physics questions, such as the role of pH and metal to ligand ratio, illuminating both the macroscopic and microscopic material behavior. These understandings further bio-inspired engineering techniques that are used to design viscoelastic soft materials. I was supported by the Department of Defense (DoD) through the National Defense Science & Engineering Graduate Fellowship (NDSEG) Program.

FlowGo: An Educational Kit for Fluid Dynamics and Heat Transfer

NASA Astrophysics Data System (ADS)

Guri, Dominic; Portsmore, Merredith; Kemmerling, Erica

2015-11-01

The authors have designed and prototyped an educational toolkit that will help middle-school-aged students learn fundamental fluid mechanics and heat transfer concepts in a hands-on play environment. The kit allows kids to build arbitrary flow rigs to solve fluid mechanics and heat transfer challenge problems. Similar kits for other engineering fields, such as structural and electrical engineering, have resulted in pedagogical improvements, particularly in early engineering education, where visual demonstrations have a significant impact. Using the FlowGo kit, students will be able to conduct experiments and develop new design ideas to solve challenge problems such as building plant watering systems or modeling water and sewage reticulation. The toolkit consists of components such as tubes, junctions, and reservoirs that easily snap together via a modular, universal connector. Designed with the Massachusetts K-12 science standards in mind, this kit is intended to be affordable and suitable for classroom use. Results and user feedback from students conducting preliminary tests of the kit will be presented.

Coupled multi-disciplinary simulation of composite engine structures in propulsion environment

NASA Technical Reports Server (NTRS)

Chamis, Christos C.; Singhal, Surendra N.

1992-01-01

A computational simulation procedure is described for the coupled response of multi-layered multi-material composite engine structural components which are subjected to simultaneous multi-disciplinary thermal, structural, vibration, and acoustic loadings including the effect of hostile environments. The simulation is based on a three dimensional finite element analysis technique in conjunction with structural mechanics codes and with acoustic analysis methods. The composite material behavior is assessed at the various composite scales, i.e., the laminate/ply/constituents (fiber/matrix), via a nonlinear material characterization model. Sample cases exhibiting nonlinear geometrical, material, loading, and environmental behavior of aircraft engine fan blades, are presented. Results for deformed shape, vibration frequency, mode shapes, and acoustic noise emitted from the fan blade, are discussed for their coupled effect in hot and humid environments. Results such as acoustic noise for coupled composite-mechanics/heat transfer/structural/vibration/acoustic analyses demonstrate the effectiveness of coupled multi-disciplinary computational simulation and the various advantages of composite materials compared to metals.

A biomimetic three-dimensional woven composite scaffold for functional tissue engineering of cartilage

NASA Astrophysics Data System (ADS)

Moutos, Franklin T.; Freed, Lisa E.; Guilak, Farshid

2007-02-01

Tissue engineering seeks to repair or regenerate tissues through combinations of implanted cells, biomaterial scaffolds and biologically active molecules. The rapid restoration of tissue biomechanical function remains an important challenge, emphasizing the need to replicate structural and mechanical properties using novel scaffold designs. Here we present a microscale 3D weaving technique to generate anisotropic 3D woven structures as the basis for novel composite scaffolds that are consolidated with a chondrocyte-hydrogel mixture into cartilage tissue constructs. Composite scaffolds show mechanical properties of the same order of magnitude as values for native articular cartilage, as measured by compressive, tensile and shear testing. Moreover, our findings showed that porous composite scaffolds could be engineered with initial properties that reproduce the anisotropy, viscoelasticity and tension-compression nonlinearity of native articular cartilage. Such scaffolds uniquely combine the potential for load-bearing immediately after implantation in vivo with biological support for cell-based tissue regeneration without requiring cultivation in vitro.

Advanced Propfan Engine Technology (APET) definition study, single and counter-rotation gearbox/pitch change mechanism design

NASA Technical Reports Server (NTRS)

Anderson, R. D.

1985-01-01

Single-rotation propfan-powered regional transport aircraft were studied to identify key technology development issues and programs. The need for improved thrust specific fuel consumption to reduce fuel burned and aircraft direct operating cost is the dominant factor. Typical cycle trends for minimizing fuel consumption are reviewed, and two 10,000 shp class engine configurations for propfan propulsion systems for the 1990's are presented. Recommended engine configurations are both three-spool design with dual spool compressors and free power turbines. The benefits of these new propulsion system concepts were evaluated using an advanced airframe, and results are compared for single-rotation propfan and turbofan advanced technology propulsion systems. The single-rotation gearbox is compared to a similar design with current technology to establish the benefits of the advanced gearbox technology. The conceptual design of the advanced pitch change mechanism identified a high pressure hydraulic system that is superior to the other contenders and completely external to the gearboxes.

Modeling of a data exchange process in the Automatic Process Control System on the base of the universal SCADA-system

NASA Astrophysics Data System (ADS)

Topolskiy, D.; Topolskiy, N.; Solomin, E.; Topolskaya, I.

2016-04-01

In the present paper the authors discuss some ways of solving energy saving problems in mechanical engineering. In authors' opinion one of the ways of solving this problem is integrated modernization of power engineering objects of mechanical engineering companies, which should be intended for the energy supply control efficiency increase and electric energy commercial accounting improvement. The author have proposed the usage of digital current and voltage transformers for these purposes. To check the compliance of this equipment with the IEC 61850 International Standard, we have built a mathematic model of the data exchange process between measuring transformers and a universal SCADA-system. The results of modeling show that the discussed equipment corresponds to the mentioned Standard requirements and the usage of the universal SCADA-system for these purposes is preferable and economically reasonable. In modeling the authors have used the following software: MasterScada, Master OPC_DI_61850, OPNET.

Engineering Graphene Mechanical Systems

DTIC Science & Technology

2012-07-05

strength material. On the basis of chemical /defect manipulation and recrystallization this technique allows wide-range engineering of mechanical... Engineering Graphene Mechanical Systems Maxim K. Zalalutdinov,† Jeremy T. Robinson,*,† Chad E. Junkermeier,‡ James C. Culbertson, Thomas L. Reinecke...Information ABSTRACT: We report a method to introduce direct bonding between graphene platelets that enables the transformation of a multilayer chemically

14 CFR 13.18 - Civil penalties: Administrative assessment against an individual acting as a pilot, flight...

Code of Federal Regulations, 2013 CFR

2013-01-01

... against an individual acting as a pilot, flight engineer, mechanic, or repairman. 13.18 Section 13.18... assessment against an individual acting as a pilot, flight engineer, mechanic, or repairman. (a) General. (1... procedures against an individual acting as a pilot, flight engineer, mechanic, or repairman, under 49 U.S.C...

77 FR 3073 - American Society of Mechanical Engineers (ASME) Codes and New and Revised ASME Code Cases...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-23

... NUCLEAR REGULATORY COMMISSION 10 CFR Part 50 [NRC-2008-0554] RIN 3150-AI35 American Society of Mechanical Engineers (ASME) Codes and New and Revised ASME Code Cases; Corrections AGENCY: Nuclear Regulatory... the American Society of Mechanical Engineers, Three Park Avenue, New York, NY 10016, phone (800) 843...

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

PubMed

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.

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

PubMed Central

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. PMID:26989897

Airframe-Jet Engine Integration Noise

NASA Technical Reports Server (NTRS)

Tam, Christopher; Antcliff, Richard R. (Technical Monitor)

2003-01-01

It has been found experimentally that the noise radiated by a jet mounted under the wing of an aircraft exceeds that of the same jet in a stand-alone environment. The increase in noise is referred to as jet engine airframe integration noise. The objectives of the present investigation are, (1) To obtain a better understanding of the physical mechanisms responsible for jet engine airframe integration noise or installation noise. (2) To develop a prediction model for jet engine airframe integration noise. It is known that jet mixing noise consists of two principal components. They are the noise from the large turbulence structures of the jet flow and the noise from the fine scale turbulence. In this investigation, only the effect of jet engine airframe interaction on the fine scale turbulence noise of a jet is studied. The fine scale turbulence noise is the dominant noise component in the sideline direction. Thus we limit out consideration primarily to the sideline.

Engineering, technology and science disciplines and gender difference: a case study among Indian students

NASA Astrophysics Data System (ADS)

Cheruvalath, Reena

2018-01-01

It is proposed to examine the argument that females cannot perform better in engineering and science fields because of their poor mathematical or logical reasoning. The major reason for the reduced number of females in the above fields in India is the socio-cultural aversion towards females choosing the field and restriction in providing higher education for them by their parents. The present study shows that the females who get the opportunity to study engineering and science perform equal to or better than their male counterparts. An analysis of CGPA (Cumulative Grade Point Average) of 2631 students who have completed their engineering or science programme in one of the top engineering colleges in India for five years shows that female academic performance is equal to or better than that of males. Mathematical, logical, verbal and mechanical reasoning are tested while calculating CGPA.

Development Status and Performance Comparisons of Environmental Barrier Coating Systems for SiCSiC Ceramic Matrix Composites

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Harder, Bryan

2016-01-01

Environmental barrier coatings (EBC) and SiCSiC ceramic matrix composites (CMCs) will play a crucial role in future aircraft turbine engine systems, because of their ability to significantly increase engine operating temperatures, reduce engine weight and cooling requirements. This paper presents current NASA EBC-CMC development emphases including: the coating composition and processing improvements, laser high heat flux-thermal gradient thermo-mechanical fatigue - environmental testing methodology development, and property evaluations for next generation EBC-CMC systems. EBCs processed with various deposition techniques including Plasma Spray, Electron Beam - Physical Vapor Deposition, and Plasma Spray Physical Vapor Deposition (PS-PVD) will be particularly discussed. The testing results and demonstrations of advanced EBCs-CMCs in complex simulated engine thermal gradient cyclic fatigue, oxidizing-steam and CMAS environments will help provide insights into the coating development strategies to meet long-term engine component durability goals.

Exergy analysis of electrically- and thermally-driven engines to drive heat pumps: An exhaustive comparative study

DOE PAGES

Ally, Moonis R.; Sharma, Vishaldeep; Abdelaziz, Omar

2017-02-21

The choice of driving a heat pump with an electrically$-$or a thermally-driven engine is a vexing question complicated by the carbon footprint and environmental impact of using electricity versus natural gas (or waste heat) as the main driver for the respective engines. The amount of useful work generated by these two distinct engines is the focal point of this paper, which addresses a key question: which engine presents a better choice for a given heat pumping application within the constraints of energy and environmental stewardship? Extensive use of energy, exergy, and availability analysis is necessary to quantify the useful workmore » and to examine the issue holistically for both types of engines. The methodology explains why the output of work from these two distinct engines to satisfy a given load is vastly different, a direct consequence of their inherent Irreversibility. Thermodynamic consistency is guaranteed by satisfaction of the First and Second Laws applied to closed systems and their subsystems. The general conclusion is that thermally-driven engines are not industrious converters of heat to mechanical work.« less

Recent developments in turbomachinery component materials and manufacturing challenges for aero engine applications

NASA Astrophysics Data System (ADS)

Srinivas, G.; Raghunandana, K.; Satish Shenoy, B.

2018-02-01

In the recent years the development of turbomachinery materials performance enhancement plays a vital role especially in aircraft air breathing engines like turbojet engine, turboprop engine, turboshaft engine and turbofan engines. Especially the transonic flow engines required highly sophisticated materials where it can sustain the entire thrust which can create by the engine. The main objective of this paper is to give an overview of the present cost-effective and technological capabilities process for turbomachinery component materials. Especially the main focus is given to study the Electro physical, Photonic additive removal process and Electro chemical process for turbomachinery parts manufacture. The aeronautical propulsion based technologies are reviewed thoroughly where in surface reliability, geometrical precession, and material removal and highly strengthened composite material deposition rates usually difficult to cut dedicated steels, Titanium and Nickel based alloys. In this paper the past aeronautical and propulsion mechanical based manufacturing technologies, current sophisticated technologies and also future challenging material processing techniques are covered. The paper also focuses on the brief description of turbomachinery components of shaping process and coating in aeromechanical applications.

Exergy analysis of electrically- and thermally-driven engines to drive heat pumps: An exhaustive comparative study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ally, Moonis R.; Sharma, Vishaldeep; Abdelaziz, Omar

The choice of driving a heat pump with an electrically$-$or a thermally-driven engine is a vexing question complicated by the carbon footprint and environmental impact of using electricity versus natural gas (or waste heat) as the main driver for the respective engines. The amount of useful work generated by these two distinct engines is the focal point of this paper, which addresses a key question: which engine presents a better choice for a given heat pumping application within the constraints of energy and environmental stewardship? Extensive use of energy, exergy, and availability analysis is necessary to quantify the useful workmore » and to examine the issue holistically for both types of engines. The methodology explains why the output of work from these two distinct engines to satisfy a given load is vastly different, a direct consequence of their inherent Irreversibility. Thermodynamic consistency is guaranteed by satisfaction of the First and Second Laws applied to closed systems and their subsystems. The general conclusion is that thermally-driven engines are not industrious converters of heat to mechanical work.« less

Compression Ratio Adjuster

NASA Technical Reports Server (NTRS)

Akkerman, J. W.

1982-01-01

New mechanism alters compression ratio of internal-combustion engine according to load so that engine operates at top fuel efficiency. Ordinary gasoline, diesel and gas engines with their fixed compression ratios are inefficient at partial load and at low-speed full load. Mechanism ensures engines operate as efficiently under these conditions as they do at highload and high speed.

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

ERIC Educational Resources Information Center

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…

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

ERIC Educational Resources Information Center

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…

Learning Activity Packets for Auto Mechanics II. Section A--Engine Rebuilding.

ERIC Educational Resources Information Center

Oklahoma State Board of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

Eight learning activity packets (LAPs) are provided for the instructional area of engine rebuilding in the auto mechanics II program. They accompany an instructor's guide available separately. The LAPs outline the study activities and performance tasks for these eight units: (1) engine condition evaluation; (2) engine removal; (3) engine…

Auto Mechanics I. Learning Activity Packets (LAPs). Section C--Engine.

ERIC Educational Resources Information Center

Oklahoma State Board of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

This document contains five learning activity packets (LAPs) that outline the study activities for the "engine" instructional area for an Auto Mechanics I course. The five LAPs cover the following topics: basic engine principles, cooling system, engine lubrication system, exhaust system, and fuel system. Each LAP contains a cover sheet…

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

ERIC Educational Resources Information Center

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…

The knowledge instinct, cognitive algorithms, modeling of language and cultural evolution

NASA Astrophysics Data System (ADS)

Perlovsky, Leonid I.

2008-04-01

The talk discusses mechanisms of the mind and their engineering applications. The past attempts at designing "intelligent systems" encountered mathematical difficulties related to algorithmic complexity. The culprit turned out to be logic, which in one way or another was used not only in logic rule systems, but also in statistical, neural, and fuzzy systems. Algorithmic complexity is related to Godel's theory, a most fundamental mathematical result. These difficulties were overcome by replacing logic with a dynamic process "from vague to crisp," dynamic logic. It leads to algorithms overcoming combinatorial complexity, and resulting in orders of magnitude improvement in classical problems of detection, tracking, fusion, and prediction in noise. I present engineering applications to pattern recognition, detection, tracking, fusion, financial predictions, and Internet search engines. Mathematical and engineering efficiency of dynamic logic can also be understood as cognitive algorithm, which describes fundamental property of the mind, the knowledge instinct responsible for all our higher cognitive functions: concepts, perception, cognition, instincts, imaginations, intuitions, emotions, including emotions of the beautiful. I present our latest results in modeling evolution of languages and cultures, their interactions in these processes, and role of music in cultural evolution. Experimental data is presented that support the theory. Future directions are outlined.

Video Outreach Graduate Program.

ERIC Educational Resources Information Center

Rigas, Anthony L.

The University of Idaho's video outreach graduate program is described. The program is designed to provide continuing education, credit courses, and graduate degree-granting programs anywhere in the state by producing these programs on video cassette and Betamax formats. Presently the Master of Engineering in electrical and Mechanical Engineering…

Thomas D. Foust, Ph.D, P.E. | NREL

Science.gov Websites

-June 1997 Mechanical Systems Engineer, Nuclear Energy Program, DOE, August 1990-August 1992 Test Production," Science (2007) Heat Exchanger Performance Enhancement Methodologies, DOE Technical Report Separation Systems for Bioenergy Separations," presented at 24th Symposium on Biotechnology for Fuels

Robotics technology discipline

NASA Technical Reports Server (NTRS)

Montemerlo, Melvin D.

1990-01-01

Viewgraphs on robotics technology discipline for Space Station Freedom are presented. Topics covered include: mechanisms; sensors; systems engineering processes for integrated robotics; man/machine cooperative control; 3D-real-time machine perception; multiple arm redundancy control; manipulator control from a movable base; multi-agent reasoning; and surfacing evolution technologies.

Flight Mechanics Experiment Onboard NASA's Zero Gravity Aircraft

ERIC Educational Resources Information Center

Matthews, Kyle R.; Motiwala, Samira A.; Edberg, Donald L.; García-Llama, Eduardo

2012-01-01

This paper presents a method to promote STEM (Science, Technology, Engineering, and Mathematics) education through participation in a reduced gravity program with NASA (National Aeronautics and Space Administration). Microgravity programs with NASA provide students with a unique opportunity to conduct scientific research with innovative and…

Effect of Surface Impulsive Thermal Loads on Fatigue Behavior of Constant Volume Propulsion Engine Combustor Materials

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Fox, Dennis S.; Miller, Robert A.; Ghosn, Louis J.; Kalluri, Sreeramesh

2004-01-01

The development of advanced high performance constant-volume-combustion-cycle engines (CVCCE) requires robust design of the engine components that are capable of enduring harsh combustion environments under high frequency thermal and mechanical fatigue conditions. In this study, a simulated engine test rig has been established to evaluate thermal fatigue behavior of a candidate engine combustor material, Haynes 188, under superimposed CO2 laser surface impulsive thermal loads (30 to 100 Hz) in conjunction with the mechanical fatigue loads (10 Hz). The mechanical high cycle fatigue (HCF) testing of some laser pre-exposed specimens has also been conducted under a frequency of 100 Hz to determine the laser surface damage effect. The test results have indicated that material surface oxidation and creep-enhanced fatigue is an important mechanism for the surface crack initiation and propagation under the simulated CVCCE engine conditions.

The development and application of CFD technology in mechanical engineering

NASA Astrophysics Data System (ADS)

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.

From GCode to STL: Reconstruct Models from 3D Printing as a Service

NASA Astrophysics Data System (ADS)

Baumann, Felix W.; Schuermann, Martin; Odefey, Ulrich; Pfeil, Markus

2017-12-01

The authors present a method to reverse engineer 3D printer specific machine instructions (GCode) to a point cloud representation and then a STL (Stereolithography) file format. GCode is a machine code that is used for 3D printing among other applications, such as CNC routers. Such code files contain instructions for the 3D printer to move and control its actuator, in case of Fused Deposition Modeling (FDM), the printhead that extrudes semi-molten plastics. The reverse engineering method presented here is based on the digital simulation of the extrusion process of FDM type 3D printing. The reconstructed models and pointclouds do not accommodate for hollow structures, such as holes or cavities. The implementation is performed in Python and relies on open source software and libraries, such as Matplotlib and OpenCV. The reconstruction is performed on the model’s extrusion boundary and considers mechanical imprecision. The complete reconstruction mechanism is available as a RESTful (Representational State Transfer) Web service.

Porous magnesium-based scaffolds for tissue engineering.

PubMed

Yazdimamaghani, Mostafa; Razavi, Mehdi; Vashaee, Daryoosh; Moharamzadeh, Keyvan; Boccaccini, Aldo R; Tayebi, Lobat

2017-02-01

Significant amount of research efforts have been dedicated to the development of scaffolds for tissue engineering. Although at present most of the studies are focused on non-load bearing scaffolds, many scaffolds have also been investigated for hard tissue repair. In particular, metallic scaffolds are being studied for hard tissue engineering due to their suitable mechanical properties. Several biocompatible metallic materials such as stainless steels, cobalt alloys, titanium alloys, tantalum, nitinol and magnesium alloys have been commonly employed as implants in orthopedic and dental treatments. They are often used to replace and regenerate the damaged bones or to provide structural support for healing bone defects. Among the common metallic biomaterials, magnesium (Mg) and a number of its alloys are effective because of their mechanical properties close to those of human bone, their natural ionic content that may have important functional roles in physiological systems, and their in vivo biodegradation characteristics in body fluids. Due to such collective properties, Mg based alloys can be employed as biocompatible, bioactive, and biodegradable scaffolds for load-bearing applications. Recently, porous Mg and Mg alloys have been specially suggested as metallic scaffolds for bone tissue engineering. With further optimization of the fabrication techniques, porous Mg is expected to make a promising hard substitute scaffold. The present review covers research conducted on the fabrication techniques, surface modifications, properties and biological characteristics of Mg alloys based scaffolds. Furthermore, the potential applications, challenges and future trends of such degradable metallic scaffolds are discussed in detail. Copyright © 2016 Elsevier B.V. All rights reserved.

Joining and Integration of Silicon Carbide for Turbine Engine Applications

NASA Technical Reports Server (NTRS)

Halbig, Michael C.; Singh, Mrityunjay; Coddington, Bryan; Asthana, Rajiv

2010-01-01

The critical need for ceramic joining and integration technologies is becoming better appreciated as the maturity level increases for turbine engine components fabricated from ceramic and ceramic matrix composite materials. Ceramic components offer higher operating temperatures and reduced cooling requirements. This translates into higher efficiencies and lower emissions. For fabricating complex shapes, diffusion bonding of silicon carbide (SiC) to SiC is being developed. For the integration of ceramic parts to the surrounding metallic engine system, brazing of SiC to metals is being developed. Overcoming the chemical, thermal, and mechanical incompatibilities between dissimilar materials is very challenging. This presentation will discuss the types of ceramic components being developed by researchers and industry and the benefits of using ceramic components. Also, the development of strong, crack-free, stable bonds will be discussed. The challenges and progress in developing joining and integration approaches for a specific application, i.e. a SiC injector, will be presented.

Computational structural mechanics for engine structures

NASA Technical Reports Server (NTRS)

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.

Preloaded joint analysis methodology for space flight systems

NASA Technical Reports Server (NTRS)

Chambers, Jeffrey A.

1995-01-01

This report contains a compilation of some of the most basic equations governing simple preloaded joint systems and discusses the more common modes of failure associated with such hardware. It is intended to provide the mechanical designer with the tools necessary for designing a basic bolted joint. Although the information presented is intended to aid in the engineering of space flight structures, the fundamentals are equally applicable to other forms of mechanical design.

Dynamic Manipulation of Hydrogels to Control Cell Behavior: A Review

PubMed Central

Vats, Kanika

2013-01-01

For many tissue engineering applications and studies to understand how materials fundamentally affect cellular functions, it is important to have the ability to synthesize biomaterials that can mimic elements of native cell–extracellular matrix interactions. Hydrogels possess many properties that are desirable for studying cell behavior. For example, hydrogels are biocompatible and can be biochemically and mechanically altered by exploiting the presentation of cell adhesive epitopes or by changing hydrogel crosslinking density. To establish physical and biochemical tunability, hydrogels can be engineered to alter their properties upon interaction with external driving forces such as pH, temperature, electric current, as well as exposure to cytocompatible irradiation. Additionally, hydrogels can be engineered to respond to enzymes secreted by cells, such as matrix metalloproteinases and hyaluronidases. This review details different strategies and mechanisms by which biomaterials, specifically hydrogels, can be manipulated dynamically to affect cell behavior. By employing the appropriate combination of stimuli and hydrogel composition and architecture, cell behavior such as adhesion, migration, proliferation, and differentiation can be controlled in real time. This three-dimensional control in cell behavior can help create programmable cell niches that can be useful for fundamental cell studies and in a variety of tissue engineering applications. PMID:23541134

Current Results and Proposed Activities in Microgravity Fluid Dynamics

NASA Technical Reports Server (NTRS)

Polezhaev, V. I.

1996-01-01

The Institute for Problems in Mechanics' Laboratory work in mathematical and physical modelling of fluid mechanics develops models, methods, and software for analysis of fluid flow, instability analysis, direct numerical modelling and semi-empirical models of turbulence, as well as experimental research and verification of these models and their applications in technological fluid dynamics, microgravity fluid mechanics, geophysics, and a number of engineering problems. This paper presents an overview of the results in microgravity fluid dynamics research during the last two years. Nonlinear problems of weakly compressible and compressible fluid flows are discussed.

2. Photographic copy of engineering drawing showing mechanical systems in ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. Photographic copy of engineering drawing showing mechanical systems in plan and sections of Test Stand 'E,' including tunnel entrance. California Institute of Technology, Jet Propulsion Laboratory, Plant Engineering 'Bldg. E-60 Mechanical, Solid Propellant Test Stand,' sheet E60/13-4, June 20, 1961. - Jet Propulsion Laboratory Edwards Facility, Test Stand E, Edwards Air Force Base, Boron, Kern County, CA

14 CFR 13.16 - Civil Penalties: Administrative assessment against a person other than an individual acting as a...

Code of Federal Regulations, 2012 CFR

2012-01-01

... against a person other than an individual acting as a pilot, flight engineer, mechanic, or repairman... assessment against a person other than an individual acting as a pilot, flight engineer, mechanic, or... as a pilot, flight engineer, mechanic, or repairman for a violation cited in the first sentence of 49...

14 CFR 13.16 - Civil Penalties: Administrative assessment against a person other than an individual acting as a...

Code of Federal Regulations, 2011 CFR

2011-01-01

... against a person other than an individual acting as a pilot, flight engineer, mechanic, or repairman... assessment against a person other than an individual acting as a pilot, flight engineer, mechanic, or... as a pilot, flight engineer, mechanic, or repairman for a violation cited in the first sentence of 49...

14 CFR 13.16 - Civil Penalties: Administrative assessment against a person other than an individual acting as a...

Code of Federal Regulations, 2014 CFR

2014-01-01

... against a person other than an individual acting as a pilot, flight engineer, mechanic, or repairman... assessment against a person other than an individual acting as a pilot, flight engineer, mechanic, or... as a pilot, flight engineer, mechanic, or repairman for a violation cited in the first sentence of 49...

14 CFR 13.16 - Civil Penalties: Administrative assessment against a person other than an individual acting as a...

Code of Federal Regulations, 2013 CFR

2013-01-01

... against a person other than an individual acting as a pilot, flight engineer, mechanic, or repairman... assessment against a person other than an individual acting as a pilot, flight engineer, mechanic, or... as a pilot, flight engineer, mechanic, or repairman for a violation cited in the first sentence of 49...

14 CFR 13.16 - Civil Penalties: Administrative assessment against a person other than an individual acting as a...

Code of Federal Regulations, 2010 CFR

2010-01-01

... against a person other than an individual acting as a pilot, flight engineer, mechanic, or repairman... assessment against a person other than an individual acting as a pilot, flight engineer, mechanic, or... as a pilot, flight engineer, mechanic, or repairman for a violation cited in the first sentence of 49...

Modeling, Analysis, and Optimization Issues for Large Space Structures.

DTIC Science & Technology

1983-02-01

There are numerous opportunities - provided by new advances in computer hardware, firmware, software , CAD/CAM systems, computational algorithms and...Institute Department of Mechanical Engineering Dept. of Civil Engineering & Mechanics Troy, NY 12181 Drexel University Philadelphia, PA 19104 Dr...Mechanical Engineering Hampton, VA 23665 Washington, DC 20059 Dr. K. T. Alfriend Mr. Siva S. Banda Department of the Navy Flight Dynamics LaboratoryNaval

Mechanical preconditioning enables electrophysiologic coupling of skeletal myoblast cells to myocardium

PubMed Central

Treskes, Philipp; Cowan, Douglas B.; Stamm, Christof; Rubach, Martin; Adelmann, Roland; Wittwer, Thorsten; Wahlers, Thorsten

2015-01-01

Objective The effect of mechanical preconditioning on skeletal myoblasts in engineered tissue constructs was investigated to resolve issues associated with conduction block between skeletal myoblast cells and cardiomyocytes. Methods Murine skeletal myoblasts were used to generate engineered tissue constructs with or without application of mechanical strain. After in vitro myotube formation, engineered tissue constructs were co-cultured for 6 days with viable embryonic heart slices. With the use of sharp electrodes, electrical coupling between engineered tissue constructs and embryonic heart slices was assessed in the presence or absence of pharmacologic agents. Results The isolation and expansion procedure for skeletal myoblasts resulted in high yields of homogeneously desmin-positive (97.1% ± 0.1%) cells. Mechanical strain was exerted on myotubes within engineered tissue constructs during gelation of the matrix, generating preconditioned engineered tissue constructs. Electrical coupling between preconditioned engineered tissue constructs and embryonic heart slices was observed; however, no coupling was apparent when engineered tissue constructs were not subjected to mechanical strain. Coupling of cells from engineered tissue constructs to cells in embryonic heart slices showed slower conduction velocities than myocardial cells with the embryonic heart slices (preconditioned engineered tissue constructs vs embryonic heart slices: 0.04 ± 0.02 ms vs 0.10 ± 0.05 ms, P = .011), lower stimulation frequencies (preconditioned engineered tissue constructs vs maximum embryonic heart slices: 4.82 ± 1.42 Hz vs 10.58 ± 1.56 Hz; P = .0009), and higher sensitivities to the gap junction inhibitor (preconditioned engineered tissue constructs vs embryonic heart slices: 0.22 ± 0.07 mmol/L vs 0.93 ± 0.15 mmol/L; P = .0004). Conclusions We have generated skeletal myoblast–based transplantable grafts that electrically couple to myocardium. PMID:22980065

Fabrication and Assembly of High-Precision Hinge and Latch Joints for Deployable Optical Instruments

NASA Technical Reports Server (NTRS)

Phelps, James E.

1999-01-01

Descriptions are presented of high-precision hinge and latch joints that have been co-developed, for application to deployable optical instruments, by NASA Langley Research Center and Nyma/ADF. Page-sized versions of engineering drawings are included in two appendices to describe all mechanical components of both joints. Procedures for assembling the mechanical components of both joints are also presented. The information herein is intended to facilitate the fabrication and assembly of the high-precision hinge and latch joints, and enable the incorporation of these joints into the design of deployable optical instrument systems.

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

NASA Astrophysics Data System (ADS)

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.

“Engineering Substrate Micro- and Nanotopography to Control Cell Function”

PubMed Central

Bettinger, Christopher J; Langer, Robert; Borenstein, Jeffrey T

2010-01-01

Lead-In The interaction of mammalian cells with nanoscale topography has proven to be an important signaling modality in controlling cell function. Naturally occurring nanotopographic structures within the extracellular matrix present surrounding cells with mechanotransductive cues that influence local migration, cell polarization, and other functions. Synthetically nanofabricated topography can also influence cell morphology, alignment, adhesion, migration, proliferation, and cytoskeleton organization. Here we review the use of in vitro synthetic cell-nanotopography interactions to control cell behavior and influence complex cellular processes including stem cell differentiation and tissue organization. Future challenges and opportunities in cell-nanotopography engineering will also be discussed including the elucidation of mechanisms and applications in tissue engineering. PMID:19492373

Fabrication of ceramic substrate-reinforced and free forms by mandrel plasma spraying metal-ceramic composites

NASA Technical Reports Server (NTRS)

Quentmeyer, R. J.; Mcdonald, G.; Hendricks, R. C.

1985-01-01

Components fabricated of, or coated with, ceramics have lower parasitic cooling requirements. Techniques are discussed for fabricating thin-shell ceramic components and ceramic coatings for applications in rocket or jet engine environments. Thin ceramic shells with complex geometric forms involving convolutions and reentrant surfaces were fabricated by mandrel removal. Mandrel removal was combined with electroplating or plasma spraying and isostatic pressing to form a metal support for the ceramic. Rocket engine thrust chambers coated with 0.08 mm (3 mil) of ZrO2-8Y2O3 had no failures and a tenfold increase in engine life. Some measured mechanical properties of the plasma-sprayed ceramic are presented.

Testing and analysis of the impact on engine cycle parameters and control system modifications using hydrogen or methane as fuel in an industrial gas turbine

NASA Astrophysics Data System (ADS)

Funke, H. H.-W.; Keinz, J.; Börner, S.; Hendrick, P.; Elsing, R.

2016-07-01

The paper highlights the modification of the engine control software of the hydrogen (H2) converted gas turbine Auxiliary Power Unit (APU) GTCP 36-300 allowing safe and accurate methane (CH4) operation achieved without mechanical changes of the metering unit. The acceleration and deceleration characteristics of the engine controller from idle to maximum load are analyzed comparing H2 and CH4. Also, the paper presents the influence on the thermodynamic cycle of gas turbine resulting from the different fuels supported by a gas turbine cycle simulation of H2 and CH4 using the software GasTurb.

Implementation of a Goal-Based Systems Engineering Process Using the Systems Modeling Language (SysML)

NASA Technical Reports Server (NTRS)

Breckenridge, Jonathan T.; Johnson, Stephen B.

2013-01-01

This paper describes the core framework used to implement a Goal-Function Tree (GFT) based systems engineering process using the Systems Modeling Language. It defines a set of principles built upon by the theoretical approach described in the InfoTech 2013 ISHM paper titled "Goal-Function Tree Modeling for Systems Engineering and Fault Management" presented by Dr. Stephen B. Johnson. Using the SysML language, the principles in this paper describe the expansion of the SysML language as a baseline in order to: hierarchically describe a system, describe that system functionally within success space, and allocate detection mechanisms to success functions for system protection.

Grain boundary engineering: fatigue fracture

NASA Astrophysics Data System (ADS)

Das, Arpan

2017-04-01

Grain boundary engineering has revealed significant enhancement of material properties by modifying the populations and connectivity of different types of grain boundaries within the polycrystals. The character and connectivity of grain boundaries in polycrystalline microstructures control the corrosion and mechanical behaviour of materials. A comprehensive review of the previous researches has been carried out to understand this philosophy. Present research thoroughly explores the effect of total strain amplitude on phase transformation, fatigue fracture features, grain size, annealing twinning, different grain connectivity and grain boundary network after strain controlled low cycle fatigue deformation of austenitic stainless steel under ambient temperature. Electron backscatter diffraction technique has been used extensively to investigate the grain boundary characteristics and morphologies. The nominal variation of strain amplitude through cyclic plastic deformation is quantitatively demonstrated completely in connection with the grain boundary microstructure and fractographic features to reveal the mechanism of fatigue fracture of polycrystalline austenite. The extent of boundary modifications has been found to be a function of the number of applied loading cycles and strain amplitudes. It is also investigated that cyclic plasticity induced martensitic transformation strongly influences grain boundary characteristics and modifications of the material's microstructure/microtexture as a function of strain amplitudes. The experimental results presented here suggest a path to grain boundary engineering during fatigue fracture of austenite polycrystals.

Transport phenomena in environmental engineering

NASA Astrophysics Data System (ADS)

Sander, Aleksandra; Kardum, Jasna Prlić; Matijašić, Gordana; Žižek, Krunoslav

2018-01-01

A term transport phenomena arises as a second paradigm at the end of 1950s with high awareness that there was a strong need to improve the scoping of chemical engineering science. At that point, engineers became highly aware that it is extremely important to take step forward from pure empirical description and the concept of unit operations only to understand the specific process using phenomenological equations that rely on three elementary physical processes: momentum, energy and mass transport. This conceptual evolution of chemical engineering was first presented with a well-known book of R. Byron Bird, Warren E. Stewart and Edwin N. Lightfoot, Transport Phenomena, published in 1960 [1]. What transport phenomena are included in environmental engineering? It is hard to divide those phenomena through different engineering disciplines. The core is the same but the focus changes. Intention of the authors here is to present the transport phenomena that are omnipresent in treatment of various process streams. The focus in this chapter is made on the transport phenomena that permanently occur in mechanical macroprocesses of sedimentation and filtration for separation in solid-liquid particulate systems and on the phenomena of the flow through a fixed and a fluidized bed of particles that are immanent in separation processes in packed columns and in environmental catalysis. The fundamental phenomena for each thermal and equilibrium separation process technology are presented as well. Understanding and mathematical description of underlying transport phenomena result in scoping the separation processes in a way that ChEs should act worldwide.

Damage-mitigating control of a reusable rocket engine for high performance and extended life

NASA Technical Reports Server (NTRS)

Ray, Asok; Dai, Xiaowen

1995-01-01

The goal of damage mitigating control in reusable rocket engines is to achieve high performance with increased durability of mechanical structures such that functional lives of the critical components are increased. The major benefit is an increase in structural durability with no significant loss of performance. This report investigates the feasibility of damage mitigating control of reusable rocket engines. Phenomenological models of creep and thermo-mechanical fatigue damage have been formulated in the state-variable setting such that these models can be combined with the plant model of a reusable rocket engine, such as the Space Shuttle Main Engine (SSME), for synthesizing an optimal control policy. Specifically, a creep damage model of the main thrust chamber wall is analytically derived based on the theories of sandwich beam and viscoplasticity. This model characterizes progressive bulging-out and incremental thinning of the coolant channel ligament leading to its eventual failure by tensile rupture. The objective is to generate a closed form solution of the wall thin-out phenomenon in real time where the ligament geometry is continuously updated to account for the resulting deformation. The results are in agreement with those obtained from the finite element analyses and experimental observation for both Oxygen Free High Conductivity (OFHC) copper and a copper-zerconium-silver alloy called NARloy-Z. Due to its computational efficiency, this damage model is suitable for on-line applications of life prediction and damage mitigating control, and also permits parametric studies for off-line synthesis of damage mitigating control systems. The results are presented to demonstrate the potential of life extension of reusable rocket engines via damage mitigating control. The control system has also been simulated on a testbed to observe how the damage at different critical points can be traded off without any significant loss of engine performance. The research work reported here is built upon concepts derived from the disciplines of Controls, Thermo-fluids, Structures, and Materials. The concept of damage mitigation, as presented in this report, is not restricted to control of rocket engines. It can be applied to any system where structural durability is an important issue.

Selective Guide to Literature on Engineering Geology. Engineering Literature Guides, Number 7.

ERIC Educational Resources Information Center

Mullen, Cecilia P., Comp.

This guide has been prepared for use by the undergraduate or graduate student in engineering geology. Because of the broad scope of the field, the major disciplines of soil mechanics, rock mechanics, and foundations are primarily emphasized. This document is a survey of information sources in engineering geology and is intended to identify those…

The Process of Updating Engineering Management Science in an Australian Regional University Excellence in Developing E-Learning

ERIC Educational Resources Information Center

Ku, H.; Fulcher, R.

2007-01-01

The aim of the current paper is to share the processes in revising the courseware of the course of "Engineering Management Science" coded as ENG4004, in the Bachelor of Engineering (Mechanical, Mechatronics, Electrical and Electronic, Computer Systems, Instrumentation and Control), Bachelor of Engineering Technology (Mechanical, Building…

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

PubMed

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.

In situ damage monitoring in vibration mechanics: diagnostics and predictive maintenance

NASA Astrophysics Data System (ADS)

Basseville, M.; Benveniste, A.; Gach-Devauchelle, B.; Goursat, M.; Bonnecase, D.; Dorey, P.; Prevosto, M.; Olagnon, M.

1993-09-01

A system identification approach is presented for damage monitoring in vibration mechanics. Identification, detection, and diagnostics are performed using accelerometer measurements from the system at work so that the excitation is not controlled, usually not observed and may involve turbulent phenomena. Targeted applications include power engineering (rotating machines, core and pipes of nuclear power plants), civil engineering (large buildings subject to hurricanes or earthquakes, bridges, dams, offshore structures), aeronautics (wings and other structures subject to strength), automobile, rail transportation etc. The method is illustrated by a laboratory example, and the results of 3 years industrial usage. This paper is a progress report on a 10 year project involving three people almost permanently. We describe here the whole approach but omit the technical details which are available in previous papers.

LARGE STRAIN STIMULATION PROMOTES EXTRACELLULAR MATRIX PRODUCTION AND STIFFNESS IN AN ELASTOMERIC SCAFFOLD MODEL

PubMed Central

D’more, Antonio; Soares, Joao; Stella, John A.; Zhang, Will; Amoroso, Nicholas J.; Mayer, John E.; Wagner, William R.; Sacks, Michael S.

2016-01-01

Mechanical conditioning of engineered tissue constructs is widely recognized as one of the most relevant methods to enhance tissue accretion and microstructure, leading to improved mechanical behaviors. The understanding of the underlying mechanisms remains rather limited, restricting the development of in silico models of these phenomena, and the translation of engineered tissues into clinical application. In the present study, we examined the role of large strip-biaxial strains (up to 50%) on ECM synthesis by vascular smooth muscle cells (VSMCs) micro-integrated into electrospun polyester urethane urea (PEUU) constructs over the course of 3 weeks. Experimental results indicated that VSMC biosynthetic behavior was quite sensitive to tissue strain maximum level, and that collagen was the primary ECM component synthesized. Moreover, we found that while a 30% peak strain level achieved maximum ECM synthesis rate, further increases in strain level lead to a reduction in ECM biosynthesis. Subsequent mechanical analysis of the formed collagen fiber network was performed by removing the scaffold mechanical responses using a strain-energy based approach, showing that the de-novo collagen also demonstrated mechanical behaviors substantially better than previously obtained with small strain training and comparable to mature collagenous tissues. We conclude that the application of large deformations can play a critical role not only in the quantity of ECM synthesis (i.e. the rate of mass production), but also on the modulation of the stiffness of the newly formed ECM constituents. The improved understanding of the process of growth and development of ECM in these mechano-sensitive cell-scaffold systems will lead to more rational design and manufacturing of engineered tissues operating under highly demanding mechanical environments. PMID:27344402

Instructional Guidelines. Welding.

ERIC Educational Resources Information Center

Fordyce, H. L.; Doshier, Dale

Using the standards of the American Welding Society and the American Society of Mechanical Engineers, this welding instructional guidelines manual presents a course of study in accordance with the current practices in industry. Intended for use in welding programs now practiced within the Federal Prison System, the phases of the program are…

Teaching Classical Mechanics Concepts Using Visuo-Haptic Simulators

ERIC Educational Resources Information Center

Neri, Luis; Noguez, Julieta; Robledo-Rella, Victor; Escobar-Castillejos, David; Gonzalez-Nucamendi, Andres

2018-01-01

In this work, the design and implementation of several physics scenarios using haptic devices are presented and discussed. Four visuo-haptic applications were developed for an undergraduate engineering physics course. Experiments with experimental and control groups were designed and implemented. Activities and exercises related to classical…

78 FR 30842 - Submission for OMB Review; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-23

... through the use of appropriate automated, electronic, mechanical, or other technological collection..., moved interstate, or released into the environment, will not present a risk of plant pest introduction... engineered organism will pose a risk to agriculture or the environment if grown in the absence of regulations...

FRONT DETAIL OF RIGHT ENGINE AND WING. MECHANICS CHECK METAL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

FRONT DETAIL OF RIGHT ENGINE AND WING. MECHANICS CHECK METAL CHIP DETECTOR ON RIGHT ENGINE. THE LEADING EDGE FLAPS ON THE RIGHT WING ARE DOWN PRIOR TO LUBRICATION. - Greater Buffalo International Airport, Maintenance Hangar, Buffalo, Erie County, NY

Accelerated testing of space mechanisms

NASA Technical Reports Server (NTRS)

Murray, S. Frank; Heshmat, Hooshang

1995-01-01

This report contains a review of various existing life prediction techniques used for a wide range of space mechanisms. Life prediction techniques utilized in other non-space fields such as turbine engine design are also reviewed for applicability to many space mechanism issues. The development of new concepts on how various tribological processes are involved in the life of the complex mechanisms used for space applications are examined. A 'roadmap' for the complete implementation of a tribological prediction approach for complex mechanical systems including standard procedures for test planning, analytical models for life prediction and experimental verification of the life prediction and accelerated testing techniques are discussed. A plan is presented to demonstrate a method for predicting the life and/or performance of a selected space mechanism mechanical component.

Mechanical cues in orofacial tissue engineering and regenerative medicine.

PubMed

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.

Tissue-Engineered Nanofibrous Nerve Grafts for Enhancing the Rate of Nerve Regeneration

DTIC Science & Technology

2015-10-01

structured nanofibrous biodegradable nerve graft system that present ECM protein, neurotrophic factor, and pre-seeded with bone marrow stromal cells in...nanofibrous biodegradable nerve graft system that present extracellular matrix (ECM) protein, nerve growth factor, and pre-seeded with bone marrow stromal...proposed novel structured nanofibrous biodegradable grafts will provide the micro environment, bioactivity, transport features and mechanics ideal for

Computational structural mechanics engine structures computational simulator

NASA Technical Reports Server (NTRS)

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.

Tribology theory versus experiment

NASA Technical Reports Server (NTRS)

Ferrante, John

1987-01-01

Tribology, the study of friction and wear of materials, has achieved a new interest because of the need for energy conservation. Fundamental understanding of this field is very complex and requires a knowledge of solid-state physics, material science, chemistry, and mechanical engineering. This paper is meant to be didactic in nature and outlines some of the considerations needed for a tribology research program. The approach is first to present a simple model, a field emission tip in contact with a flat surface, in order to elucidate important considerations, such as contact area, mechanical deformations, and interfacial bonding. Then examples from illustrative experiments are presented. Finally, the current status of physical theories concerning interfacial bonding are presented.

Engineering mechanics: statics and dynamics. [Textbook

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sandor, B.I.

1983-01-01

The purpose of this textbook is to provide engineering students with basic learning material about statics and dynamics which are fundamental engineering subjects. The chapters contain information on: an introduction to engineering mechanics; forces on particles, rigid bodies, and structures; kinetics of particles, particle systems, and rigid bodies in motion; kinematics; mechanical vibrations; and friction, work, moments of inertia, and potential energy. Each chapter contains introductory material, the development of the essential equations, worked-out example problems, homework problems, and, finally, summaries of the essential methods and equations, graphically illustrated where appropriate. (LCL)

Progress of Stirling cycle analysis and loss mechanism characterization

NASA Technical Reports Server (NTRS)

Tew, R. C., Jr.

1986-01-01

An assessment of Stirling engine thermodynamic modeling and design codes shows a general deficiency; this deficiency is due to poor understanding of the fluid flow and heat transfer phenomena that occur in the oscillating flow and pressure level environment within the engines. Stirling engine thermodynamic loss mechanisms are listed. Several experimental and computational research efforts now underway to characterize various loss mechanisms are reviewed. The need for additional experimental rigs and rig upgrades is discussed. Recent developments and current efforts in Stirling engine thermodynamic modeling are also reviewed.

Integrated approaches to spatiotemporally directing angiogenesis in host and engineered tissues.

PubMed

Kant, Rajeev J; Coulombe, Kareen L K

2018-03-15

The field of tissue engineering has turned towards biomimicry to solve the problem of tissue oxygenation and nutrient/waste exchange through the development of vasculature. Induction of angiogenesis and subsequent development of a vascular bed in engineered tissues is actively being pursued through combinations of physical and chemical cues, notably through the presentation of topographies and growth factors. Presenting angiogenic signals in a spatiotemporal fashion is beginning to generate improved vascular networks, which will allow for the creation of large and dense engineered tissues. This review provides a brief background on the cells, mechanisms, and molecules driving vascular development (including angiogenesis), followed by how biomaterials and growth factors can be used to direct vessel formation and maturation. Techniques to accomplish spatiotemporal control of vascularization include incorporation or encapsulation of growth factors, topographical engineering, and 3D bioprinting. The vascularization of engineered tissues and their application in angiogenic therapy in vivo is reviewed herein with an emphasis on the most densely vascularized tissue of the human body - the heart. Vascularization is vital to wound healing and tissue regeneration, and development of hierarchical networks enables efficient nutrient transfer. In tissue engineering, vascularization is necessary to support physiologically dense engineered tissues, and thus the field seeks to induce vascular formation using biomaterials and chemical signals to provide appropriate, pro-angiogenic signals for cells. This review critically examines the materials and techniques used to generate scaffolds with spatiotemporal cues to direct vascularization in engineered and host tissues in vitro and in vivo. Assessment of the field's progress is intended to inspire vascular applications across all forms of tissue engineering with a specific focus on highlighting the nuances of cardiac tissue engineering for the greater regenerative medicine community. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

An early glimpse at long-term subsonic commercial turbofan technology requirements. [fuel conservation

NASA Technical Reports Server (NTRS)

Gray, D. E.; Dugan, J. F.

1975-01-01

This paper reports on the exploratory investigation and initial findings of the study of future turbofan concepts to conserve fuel. To date, these studies have indicated a potential reduction in cruise thrust specific fuel consumption in 1990 turbofans of approximately 15% relative to present day new engines through advances in internal aerodynamics, structure-mechanics, and materials. Advanced materials also offer the potential for fuel savings through engine weight reduction. Further studies are required to balance fuel consumption reduction with sound airlines operational economics.

Design methodology and projects for space engineering

NASA Technical Reports Server (NTRS)

Nichols, S.; Kleespies, H.; Wood, K.; Crawford, R.

1993-01-01

NASA/USRA is an ongoing sponsor of space design projects in the senior design course of the Mechanical Engineering Department at The University of Texas at Austin. This paper describes the UT senior design sequence, consisting of a design methodology course and a capstone design course. The philosophical basis of this sequence is briefly summarized. A history of the Department's activities in the Advanced Design Program is then presented. The paper concludes with a description of the projects completed during the 1991-92 academic year and the ongoing projects for the Fall 1992 semester.

Space Station Environmental Control/Life Support System engineering

NASA Technical Reports Server (NTRS)

Miller, C. W.; Heppner, D. B.

1985-01-01

The present paper is concerned with a systems engineering study which has provided an understanding of the overall Space Station ECLSS (Environmental Control and Life Support System). ECLSS/functional partitioning is considered along with function criticality, technology alternatives, a technology description, single thread systems, Space Station architectures, ECLSS distribution, mechanical schematics per space station, and Space Station ECLSS characteristics. Attention is given to trade studies and system synergism. The Space Station functional description had been defined by NASA. The ECLSS will utilize technologies which embody regenerative concepts to minimize the use of expendables.

Knocking in the Otto-cycle Engine

NASA Technical Reports Server (NTRS)

Weinhart, H

1939-01-01

Engine knock is, as is known, preceded by normal burning of the first part of the charge, and only the part burned last (residual charge), knocks. The aim of the present measurements was, first, to reexamine the combustion form in this residual charge, because of the absence of uniform and frequently contradictory results in the very extensive literature on the subject. On top of that, an attempt was to be made to gain a deeper insight into the mechanism accompanying the combustion process, by means of the electrical test equipment perfected in recent years.

Elevated temperature biaxial fatigue

NASA Technical Reports Server (NTRS)

Jordan, E. H.

1983-01-01

Biaxial fatigue is often encountered in the complex thermo-mechanical loadings present in gas turbine engines. Engine strain histories can involve non-constant temperature, mean stress, creep, environmental effects, both isotropic and anisotropic materials and non-proportional loading. Life prediction for the general case involving all the above factors is not a practicable research project. The current research program is limited to isothermal fatigue at room temperature and 1200 F of Hastalloy-X for both proportional and non-proportional loading. An improved method for predicting the fatigue life and deformation response under biaxial cycle loading is sought.

The 1991 research and technology report, Goddard Space Flight Center

NASA Technical Reports Server (NTRS)

Soffen, Gerald (Editor); Ottenstein, Howard (Editor); Montgomery, Harry (Editor); Truszkowski, Walter (Editor); Frost, Kenneth (Editor); Sullivan, Walter (Editor); Boyle, Charles (Editor)

1991-01-01

The 1991 Research and Technology Report for Goddard Space Flight Center is presented. Research covered areas such as (1) earth sciences including upper atmosphere, lower atmosphere, oceans, hydrology, and global studies; (2) space sciences including solar studies, planetary studies, Astro-1, gamma ray investigations, and astrophysics; (3) flight projects; (4) engineering including robotics, mechanical engineering, electronics, imaging and optics, thermal and cryogenic studies, and balloons; and (5) ground systems, networks, and communications including data and networks, TDRSS, mission planning and scheduling, and software development and test.

CMC Research at NASA Glenn in 2017: Recent Progress and Plans

NASA Technical Reports Server (NTRS)

Grady, Joseph E.

2017-01-01

As part of NASA's Aeronautics research mission, Glenn Research Center has developed advanced constituents for 2700F CMC turbine engine applications. In this presentation, fiber and matrix development and characterization for SiCSiC composites will be reviewed and resulting improvements in CMC durability and mechanical properties will be summarized. Progress toward the development and validation of models predicting the effects of the engine environment on durability of CMC and Environmental Barrier Coatings will be summarized and plans for research and collaborations in 2017 will be summarized.

FLUID MECHANICS OF ARTIFICIAL HEART VALVES

PubMed Central

Dasi, Lakshmi P; Simon, Helene A; Sucosky, Philippe; Yoganathan, Ajit P

2009-01-01

SUMMARY 1. Artificial heart valves have been in use for over five decades to replace diseased heart valves. Since the first heart valve replacement performed with a caged-ball valve, more than 50 valve designs have been developed, differing principally in valve geometry, number of leaflets and material. To date, all artificial heart valves are plagued with complications associated with haemolysis, coagulation for mechanical heart valves and leaflet tearing for tissue-based valve prosthesis. For mechanical heart valves, these complications are believed to be associated with non-physiological blood flow patterns. 2. In the present review, we provide a bird’s-eye view of fluid mechanics for the major artificial heart valve types and highlight how the engineering approach has shaped this rapidly diversifying area of research. 3. Mechanical heart valve designs have evolved significantly, with the most recent designs providing relatively superior haemodynamics with very low aerodynamic resistance. However, high shearing of blood cells and platelets still pose significant design challenges and patients must undergo life-long anticoagulation therapy. Bioprosthetic or tissue valves do not require anticoagulants due to their distinct similarity to the native valve geometry and haemodynamics, but many of these valves fail structurally within the first 10–15 years of implantation. 4. These shortcomings have directed present and future research in three main directions in attempts to design superior artificial valves: (i) engineering living tissue heart valves; (ii) development of advanced computational tools; and (iii) blood experiments to establish the link between flow and blood damage. PMID:19220329

Fluid mechanics of artificial heart valves.

PubMed

Dasi, Lakshmi P; Simon, Helene A; Sucosky, Philippe; Yoganathan, Ajit P

2009-02-01

1. Artificial heart valves have been in use for over five decades to replace diseased heart valves. Since the first heart valve replacement performed with a caged-ball valve, more than 50 valve designs have been developed, differing principally in valve geometry, number of leaflets and material. To date, all artificial heart valves are plagued with complications associated with haemolysis, coagulation for mechanical heart valves and leaflet tearing for tissue-based valve prosthesis. For mechanical heart valves, these complications are believed to be associated with non-physiological blood flow patterns. 2. In the present review, we provide a bird's-eye view of fluid mechanics for the major artificial heart valve types and highlight how the engineering approach has shaped this rapidly diversifying area of research. 3. Mechanical heart valve designs have evolved significantly, with the most recent designs providing relatively superior haemodynamics with very low aerodynamic resistance. However, high shearing of blood cells and platelets still pose significant design challenges and patients must undergo life-long anticoagulation therapy. Bioprosthetic or tissue valves do not require anticoagulants due to their distinct similarity to the native valve geometry and haemodynamics, but many of these valves fail structurally within the first 10-15 years of implantation. 4. These shortcomings have directed present and future research in three main directions in attempts to design superior artificial valves: (i) engineering living tissue heart valves; (ii) development of advanced computational tools; and (iii) blood experiments to establish the link between flow and blood damage.

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

ERIC Educational Resources Information Center

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…

Should bioengineering graduates seek employment in the defense industry?

PubMed

Johnson, Arthur T

2014-01-01

They say that the difference between a mechanical engineer and a civil engineer is that the mechanical engineer develops weapons whereas a civil engineer designs targets. The implication is that some engineers are involved with building peaceful infrastructure whereas others contribute to destruction. This brings to mind the question: what is the proper role for engineers in the creation of weapons and defenses against them? In particular, should engineers specializing in biology or medicine be involved in the defense industry? After all, bioengineers are supposed to be builders or healers rather than warriors or destroyers.

Motivational project-based laboratory for a common first year electrical engineering course

NASA Astrophysics Data System (ADS)

Nedic, Zorica; Nafalski, Andrew; Machotka, Jan

2010-08-01

Over the past few years many universities worldwide have introduced a common first year for all engineering disciplines. This is despite the opinion of many academics that large classes have negative effects on the learning outcomes of first year students. The University of South Australia is also faced with low motivation amongst engineering students studying non-major courses. In 2006, a project-based laboratory was successfully introduced for first year students enrolled in electrical disciplines, which increased student satisfaction, reduced the attrition rate and improved students' success rate. This paper presents the experiences with the project-based laboratory's implementation in three different projects in the common first year course, Electrical and Energy Systems, where each project aims to increase the motivation of students in one of three disciplines: electrical, mechanical or civil engineering.

Learning analytics: Dataset for empirical evaluation of entry requirements into engineering undergraduate programs in a Nigerian university.

PubMed

Odukoya, Jonathan A; Popoola, Segun I; Atayero, Aderemi A; Omole, David O; Badejo, Joke A; John, Temitope M; Olowo, Olalekan O

2018-04-01

In Nigerian universities, enrolment into any engineering undergraduate program requires that the minimum entry criteria established by the National Universities Commission (NUC) must be satisfied. Candidates seeking admission to study engineering discipline must have reached a predetermined entry age and met the cut-off marks set for Senior School Certificate Examination (SSCE), Unified Tertiary Matriculation Examination (UTME), and the post-UTME screening. However, limited effort has been made to show that these entry requirements eventually guarantee successful academic performance in engineering programs because the data required for such validation are not readily available. In this data article, a comprehensive dataset for empirical evaluation of entry requirements into engineering undergraduate programs in a Nigerian university is presented and carefully analyzed. A total sample of 1445 undergraduates that were admitted between 2005 and 2009 to study Chemical Engineering (CHE), Civil Engineering (CVE), Computer Engineering (CEN), Electrical and Electronics Engineering (EEE), Information and Communication Engineering (ICE), Mechanical Engineering (MEE), and Petroleum Engineering (PET) at Covenant University, Nigeria were randomly selected. Entry age, SSCE aggregate, UTME score, Covenant University Scholastic Aptitude Screening (CUSAS) score, and the Cumulative Grade Point Average (CGPA) of the undergraduates were obtained from the Student Records and Academic Affairs unit. In order to facilitate evidence-based evaluation, the robust dataset is made publicly available in a Microsoft Excel spreadsheet file. On yearly basis, first-order descriptive statistics of the dataset are presented in tables. Box plot representations, frequency distribution plots, and scatter plots of the dataset are provided to enrich its value. Furthermore, correlation and linear regression analyses are performed to understand the relationship between the entry requirements and the corresponding academic performance in engineering programs. The data provided in this article will help Nigerian universities, the NUC, engineering regulatory bodies, and relevant stakeholders to objectively evaluate and subsequently improve the quality of engineering education in the country.

Numerical and Experimental Study on Manufacture of a Novel High-Capacity Engine Oil Pan Subjected to Hydro-Mechanical Deep Drawing

NASA Astrophysics Data System (ADS)

Chen, D. Y.; Xu, Y.; Zhang, S. H.; El-Aty, A. Abd; Ma, Y.

2017-09-01

The oil pan is equipped at the bottom of engine crankcase of the automobile to prevent impurity and collect the lubrication oil from the surfaces of the engine which is helpful for heat dissipation and oxidation prevention. The present study aims at manufacturing a novel high-capacity engine oil pan, which is considered as a complex shaped component with features of thin wall, large size and asymmetric deep cavity through both numerical and experimental methods. The result indicated that it is difficult to form the current part through the common deep drawing process. Accordingly, the hydro-mechanical deep drawing technology was conducted, which consisted of two steps, previous local drawing and the final integral deep drawing with hydraulic pressure. The finite element analysis (FEA) was carried out to investigate the influence of initial blank dimension and the key process parameters such as loading path, draw-bead force and fillet radius on the formability of the sheet blank. Compared with the common deep drawing, the limit drawing ratio by hydro-mechanical deep drawing can be increased from 2.34 to 2.77, while the reduction in blank wall thickness can be controlled in the range of 28%. The formability is greatly improved without any defects such as crack and wrinkle by means of parameters optimisation. The results gained from simulation keep a reasonable agreement with that obtained from experiment trials.

Braided nanofibrous scaffold for tendon and ligament tissue engineering.

PubMed

Barber, John G; Handorf, Andrew M; Allee, Tyler J; Li, Wan-Ju

2013-06-01

Tendon and ligament (T/L) injuries present an important clinical challenge due to their intrinsically poor healing capacity. Natural healing typically leads to the formation of scar-like tissue possessing inferior mechanical properties. Therefore, tissue engineering has gained considerable attention as a promising alternative for T/L repair. In this study, we fabricated braided nanofibrous scaffolds (BNFSs) as a potential construct for T/L tissue engineering. Scaffolds were fabricated by braiding 3, 4, or 5 aligned bundles of electrospun poly(L-lactic acid) nanofibers, thus introducing an additional degree of flexibility to alter the mechanical properties of individual scaffolds. We observed that the Young's modulus, yield stress, and ultimate stress were all increased in the 3-bundle compared to the 4- and 5-bundle BNFSs. Interestingly, acellular BNFSs mimicked the normal tri-phasic mechanical behavior of native tendon and ligament (T/L) during loading. When cultured on the BNFSs, human mesenchymal stem cells (hMSCs) adhered, aligned parallel to the length of the nanofibers, and displayed a concomitant realignment of the actin cytoskeleton. In addition, the BNFSs supported hMSC proliferation and induced an upregulation in the expression of key pluripotency genes. When cultured on BNFSs in the presence of tenogenic growth factors and stimulated with cyclic tensile strain, hMSCs differentiated into the tenogenic lineage, evidenced most notably by the significant upregulation of Scleraxis gene expression. These results demonstrate that BNFSs provide a versatile scaffold capable of supporting both stem cell expansion and differentiation for T/L tissue engineering applications.

ENGINE COMPRESSION AND CYLINDER LEAKAGE TESTING.

ERIC Educational Resources Information Center

Illinois Univ., Urbana. Vocational Agriculture Service.

DESIGNED FOR USE BY HIGH SCHOOL OR ADULT STUDENTS AS TEXT OR REFERENCE MATERIAL, THIS DOCUMENT PRESENTS TECHNICAL INFORMATION NEEDED IN THE FARM POWER AREA OF AGRICULTURAL MECHANICS. IT WAS DESIGNED BY SUBJECT MATTER SPECIALISTS, TEACHER EDUCATORS, SUPERVISORS, AND AN ADVISORY COMMITTEE OF TEACHERS. MAJOR SECTIONS ARE (1) WHAT ARE THE PRINCIPLES…

Heterogeneous mass transfer in HRE in the presence of electrostatic field research

NASA Astrophysics Data System (ADS)

Reshetnikov, S. M.; Zyryanov, I. A.; Budin, A. G.; Pozolotin, A. P.

2017-01-01

The paper presents research results of polymethylmethacrylate (PMMA) combustion in a hybrid rocket engine (HRE) under the influence of an electrostatic field. It is shown that the main mechanism of electrostatic field influence on the combustion rate is process changes in the condensed phase.

An investigation of equilibrium concepts

NASA Technical Reports Server (NTRS)

Prozan, R. J.

1982-01-01

A different approach to modeling of the thermochemistry of rocket engine combustion phenomena is presented. The methodology described is based on the hypothesis of a new variational principle applicable to compressible fluid mechanics. This hypothesis is extended to treat the thermochemical behavior of a reacting (equilibrium) gas in an open system.

Predictors of Visualization: A Structural Equation Model.

ERIC Educational Resources Information Center

Robichaux, Rebecca R.; Guarino, A. J.

This study tested a causal model of the development of spatial visualization based on a synthesis of past and present research. During the summer and fall of 1999, 117 third- and fourth-year undergraduates majoring in architecture, mathematics, mathematics education, and mechanical engineering completed a spatial visualization test and a…

Experimental verification of a model of a two-link flexible, lightweight manipulator. M.S. Thesis

NASA Technical Reports Server (NTRS)

Huggins, James David

1988-01-01

Experimental verification is presented for an assumed modes model of a large, two link, flexible manipulator design and constructed in the School of Mechanical Engineering at Georgia Institute of Technology. The structure was designed to have typical characteristics of a lightweight manipulator.

Some engineering aspects of the Nicholson-Koch mobile chipper

Treesearch

Donald L. Sirois

1981-01-01

A proto-type mobile chip harvester has been designed to harvest forest biomass in the form of logging residuals for use as energy wood. The proto-type is presently undergoing developmental tests. Results are encouraging, indicating mechanical feasibility with prospects of working systems within the next several years.