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.

Biomedical engineering - A means to add new dimension to medicine and research

NASA Technical Reports Server (NTRS)

Doerr, D. F.

1992-01-01

Biomedical engineering is an evolving science that seeks to insert technically oriented and trained personnel to assist medical professionals in solving technological problems in the pursuit of innovations in the delivery of health care. Consequently, engineering solutions are brought to bear on problems that previously were outside the training of physicians and beyond the understanding or appreciation of the conventionally educated electrical or mechanical engineers. This physician/scientist/engineer team has a capability to extend medicine and research far beyond the capability of a single entity operating alone. How biomedical engineering has added a new dimension to medical science at the Kennedy Space Center is described.

The current status of rehabilitation engineering

NASA Technical Reports Server (NTRS)

Reswick, J. B.

1974-01-01

Mechanical and electrical engineering devices for paralytic patient care are discussed as they are applied to medical problems. These include means of preventing bedsores, mobility aids, upper extremity orthoses, and electrical stimulation.

On the energy efficiency of cyclic mechanisms

NASA Astrophysics Data System (ADS)

Briskin, E. S.; Kalinin, Ya. V.; Maloletov, A. V.; Chernyshev, V. V.

2014-01-01

We consider cyclic mechanisms with one degree of freedom driven by engines of various types such as alternating and direct current motors, internal combustion engines, etc. We pose the problem of modifying the mechanism structure by joining additional links or by varying the parameters or operation mode of the original mechanism so as to minimize the thermal losses in the driving motor. The solution is based on the minimization of the functional determining the irreversible power losses. We show that, for the engines considered, all cyclic mechanisms with one degree of freedom should satisfy a fundamental condition ensuring the minimum of losses. We consider two examples, one of which corresponds to actually existing mechanisms.

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.

Heat transfer in damaged material

NASA Astrophysics Data System (ADS)

Kruis, J.

2013-10-01

Fully coupled thermo-mechanical analysis of civil engineering problems is studied. The mechanical analysis is based on damage mechanics which is useful for modeling of behaviour of quasi-brittle materials, especially in tension. The damage is assumed to be isotropic. The heat transfer is assumed in the form of heat conduction governed by the Fourier law and heat radiation governed by the Stefan-Boltzmann law. Fully coupled thermo-mechanical problem is formulated.

Crack Initiation and Propagation Properties of HY 130 Steel Weldments Following Temper Embrittlement.

DTIC Science & Technology

1982-09-01

mechanics ( EPFM ) may be applied to engineering problems to determine material properties related to crack initiation and propagation. Specifically, these...Introduction The application of linear elastic fracture mechanics (LEFM) to engineering fracture analyses has become increasingly widespread and the use...structures to which the particular material was to be applied. The advent of elastic-plastic fracture mechanics ( EPFM ) has proven valuable because a

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.

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…

Computational structural mechanics for engine structures

NASA Technical Reports Server (NTRS)

Chamis, Christos C.

1988-01-01

The computational structural mechanics (CSM) program at Lewis encompasses the formulation and solution of structural mechanics problems and the development of integrated software systems to computationally simulate the performance, durability, and life of engine structures. It is structured to supplement, complement, and, whenever possible, replace costly experimental efforts. Specific objectives are to investigate unique advantages of parallel and multiprocessing for reformulating and solving structural mechanics and formulating and solving multidisciplinary mechanics and to develop integrated structural system computational simulators for predicting structural performance, evaluating newly developed methods, and identifying and prioritizing improved or missing methods.

Computational structural mechanics for engine structures

NASA Technical Reports Server (NTRS)

Chamis, Christos C.

1989-01-01

The computational structural mechanics (CSM) program at Lewis encompasses the formulation and solution of structural mechanics problems and the development of integrated software systems to computationally simulate the performance, durability, and life of engine structures. It is structured to supplement, complement, and, whenever possible, replace costly experimental efforts. Specific objectives are to investigate unique advantages of parallel and multiprocessing for reformulating and solving structural mechanics and formulating and solving multidisciplinary mechanics and to develop integrated structural system computational simulators for predicting structural performance, evaluating newly developed methods, and identifying and prioritizing improved or missing methods.

Fabrication of a Neotrachea Using Engineered Cartilage

PubMed Central

Weidenbecher, Mark; Tucker, Harvey M.; Awadallah, Amad; Dennis, James E.

2008-01-01

Objectives Surgical management of long-segment tracheal stenosis is an ongoing problem. Many types of tracheal prostheses have been tried but with limited success because of immune rejection, graft ischemia, or restenosis. Tissue engineered cartilage may offer a solution to this problem, although scaffolds, which are currently often used for support, can lead to biocompatibility problems. This study investigated the feasibility of scaffold-free cartilage to tissue engineer a vascularized neotrachea in rabbits. Study Design Animal study. Methods Autologous neotracheal constructs were implanted in the abdomen of six New Zealand white rabbits. Auricular chondrocytes were used to engineer scaffold-free cartilage sheets. A muscle flap raised from the external abdominal oblique muscle and the engineered cartilage were wrapped around a silicone stent to fabricate a vascularized neotrachea in vivo. In two of the six rabbits, a full thickness skin graft was used to create an epithelial lining. The constructs were harvested after either 6 or 10 weeks. Results All neotracheal constructs were healthy with well-vascularized and integrated layers. The implanted engineered cartilage underwent a remodeling process, forming a solid tracheal framework. Constructs harvested after 10 weeks proved to have significantly better mechanical properties than after 6 weeks and were comparable with the rabbit's native trachea. Conclusion Scaffold-free engineered cartilage can successfully fabricate a well-vascularized, autologous neotrachea with excellent mechanical properties. The results suggest that this approach can be used to reconstruct tracheal defects in rabbits. PMID:18197138

Interactive training model of TRIZ for mechanical engineers in China

NASA Astrophysics Data System (ADS)

Tan, Runhua; Zhang, Huangao

2014-03-01

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

Deformation effect simulation and optimization for double front axle steering mechanism

NASA Astrophysics Data System (ADS)

Wu, Jungang; Zhang, Siqin; Yang, Qinglong

2013-03-01

This paper research on tire wear problem of heavy vehicles with Double Front Axle Steering Mechanism from the flexible effect of Steering Mechanism, and proposes a structural optimization method which use both traditional static structural theory and dynamic structure theory - Equivalent Static Load (ESL) method to optimize key parts. The good simulated and test results show this method has high engineering practice and reference value for tire wear problem of Double Front Axle Steering Mechanism design.

Design Approaches and Comparison of TAPS Packages for Engineering

ERIC Educational Resources Information Center

Sidhu, S. Manjit

2007-01-01

Purpose: The paper's purpose is to promote the use of modern technologies such as multimedia packages to engineering students. The aim is to help them to learning in their learning, visualization, problem solving and understanding engineering concepts such as in mechanics dynamics. Design/methodology/approach: TAPS packages are developed to help…

How Cognitive Style and Problem Complexity Affect Preservice Agricultural Education Teachers' Abilities to Solve Problems in Agricultural Mechanics

ERIC Educational Resources Information Center

Blackburn, J. Joey; Robinson, J. Shane; Lamm, Alexa J.

2014-01-01

The purpose of this experimental study was to determine the effects of cognitive style and problem complexity on Oklahoma State University preservice agriculture teachers' (N = 56) ability to solve problems in small gasoline engines. Time to solution was operationalized as problem solving ability. Kirton's Adaption-Innovation Inventory was…

A new chaotic multi-verse optimization algorithm for solving engineering optimization problems

NASA Astrophysics Data System (ADS)

Sayed, Gehad Ismail; Darwish, Ashraf; Hassanien, Aboul Ella

2018-03-01

Multi-verse optimization algorithm (MVO) is one of the recent meta-heuristic optimization algorithms. The main inspiration of this algorithm came from multi-verse theory in physics. However, MVO like most optimization algorithms suffers from low convergence rate and entrapment in local optima. In this paper, a new chaotic multi-verse optimization algorithm (CMVO) is proposed to overcome these problems. The proposed CMVO is applied on 13 benchmark functions and 7 well-known design problems in the engineering and mechanical field; namely, three-bar trust, speed reduce design, pressure vessel problem, spring design, welded beam, rolling element-bearing and multiple disc clutch brake. In the current study, a modified feasible-based mechanism is employed to handle constraints. In this mechanism, four rules were used to handle the specific constraint problem through maintaining a balance between feasible and infeasible solutions. Moreover, 10 well-known chaotic maps are used to improve the performance of MVO. The experimental results showed that CMVO outperforms other meta-heuristic optimization algorithms on most of the optimization problems. Also, the results reveal that sine chaotic map is the most appropriate map to significantly boost MVO's performance.

Reverse engineering and identification in systems biology: strategies, perspectives and challenges.

PubMed

Villaverde, Alejandro F; Banga, Julio R

2014-02-06

The interplay of mathematical modelling with experiments is one of the central elements in systems biology. The aim of reverse engineering is to infer, analyse and understand, through this interplay, the functional and regulatory mechanisms of biological systems. Reverse engineering is not exclusive of systems biology and has been studied in different areas, such as inverse problem theory, machine learning, nonlinear physics, (bio)chemical kinetics, control theory and optimization, among others. However, it seems that many of these areas have been relatively closed to outsiders. In this contribution, we aim to compare and highlight the different perspectives and contributions from these fields, with emphasis on two key questions: (i) why are reverse engineering problems so hard to solve, and (ii) what methods are available for the particular problems arising from systems biology?

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

Owens, J.J.; Nejedlik, J.F.; Vogt, J.W.

The SNAP II system consists of a reactor heat source, a mercury Rankine engine, and an alternator. The problems involved in selecting materials for the SNAP II mercury system were studied. A discussion is given of the corrosion mechanisms involved in a system in which mercury is the working fluid. The problem resolves itself into selecting materials with the best combination of engineering properties for the application and highest resistance to mercury corrosion at the anticipated temperature. (auth)

Wave Propagation Problems in Certain Elastic Anisotropic Half Spaces.

DTIC Science & Technology

1980-12-01

874-882. 33. Paul , S.L., and Robinson, A.R., "Interaction of Plane Elastic Waves with a Cylindrical Cavity," Technical Documentary Report Mo. RTD...Professor Paul M. Naghdi University of California Department of Mechanical Engineering Berkeley, California 94720 Professor A. J. Durelli Oakland...Burt Paul University of Pennsylvania Towne School of Civil and Mechanical Engineering Philadelphia, Pennsylvania 19104 Professor H. W. Liu Syracuse

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.

Integrating Thermal Tools Into the Mechanical Design Process

NASA Technical Reports Server (NTRS)

Tsuyuki, Glenn T.; Siebes, Georg; Novak, Keith S.; Kinsella, Gary M.

1999-01-01

The intent of mechanical design is to deliver a hardware product that meets or exceeds customer expectations, while reducing cycle time and cost. To this end, an integrated mechanical design process enables the idea of parallel development (concurrent engineering). This represents a shift from the traditional mechanical design process. With such a concurrent process, there are significant issues that have to be identified and addressed before re-engineering the mechanical design process to facilitate concurrent engineering. These issues also assist in the integration and re-engineering of the thermal design sub-process since it resides within the entire mechanical design process. With these issues in mind, a thermal design sub-process can be re-defined in a manner that has a higher probability of acceptance, thus enabling an integrated mechanical design process. However, the actual implementation is not always problem-free. Experience in applying the thermal design sub-process to actual situations provides the evidence for improvement, but more importantly, for judging the viability and feasibility of the sub-process.

Creative Engineering Based Education with Autonomous Robots Considering Job Search Support

NASA Astrophysics Data System (ADS)

Takezawa, Satoshi; Nagamatsu, Masao; Takashima, Akihiko; Nakamura, Kaeko; Ohtake, Hideo; Yoshida, Kanou

The Robotics Course in our Mechanical Systems Engineering Department offers “Robotics Exercise Lessons” as one of its Problem-Solution Based Specialized Subjects. This is intended to motivate students learning and to help them acquire fundamental items and skills on mechanical engineering and improve understanding of Robotics Basic Theory. Our current curriculum was established to accomplish this objective based on two pieces of research in 2005: an evaluation questionnaire on the education of our Mechanical Systems Engineering Department for graduates and a survey on the kind of human resources which companies are seeking and their expectations for our department. This paper reports the academic results and reflections of job search support in recent years as inherited and developed from the previous curriculum.

American & Soviet engineers examine ASTP docking set-up following tests

NASA Image and Video Library

1974-07-10

S74-25394 (10 July 1974) --- A group of American and Soviet engineers of the Apollo-Soyuz Test Project working group three examines an ASTP docking set-up following a docking mechanism fitness test conducted in Building 13 at the Johnson Space Center. Working Group No. 3 is concerned with ASTP docking problems and techniques. The joint U.S.-USSR ASTP docking mission in Earth orbit is scheduled for the summer of 1975. The Apollo docking mechanism is atop the Soyuz docking mechanism.

Applications of hybrid and digital computation methods in aerospace-related sciences and engineering. [problem solving methods at the University of Houston

NASA Technical Reports Server (NTRS)

Huang, C. J.; Motard, R. L.

1978-01-01

The computing equipment in the engineering systems simulation laboratory of the Houston University Cullen College of Engineering is described and its advantages are summarized. The application of computer techniques in aerospace-related research psychology and in chemical, civil, electrical, industrial, and mechanical engineering is described in abstracts of 84 individual projects and in reprints of published reports. Research supports programs in acoustics, energy technology, systems engineering, and environment management as well as aerospace engineering.

Education Program for Ph.D. Course to Cultivate Literacy and Competency

NASA Astrophysics Data System (ADS)

Yokono, Yasuyuki; Mitsuishi, Mamoru

The program aims to cultivate internationally competitive young researchers equipped with Fundamental attainment (mathematics, physics, chemistry and biology, and fundamental social sciences) , Specialized knowledge (mechanical dynamics, mechanics of materials, hydrodynamics, thermodynamics, design engineering, manufacturing engineering and material engineering, and bird‧s-eye view knowledge on technology, society and the environment) , Literacy (Language, information literacy, technological literacy and knowledge of the law) and Competency (Creativity, problem identification and solution, planning and execution, self-management, teamwork, leadership, sense of responsibility and sense of duty) to become future leaders in industry and academia.

Cryogenic Technology, part 1. [conference proceedings; cryogenic wind tunnel design and instrumentation

NASA Technical Reports Server (NTRS)

1980-01-01

Different engineering problems associated with the design of mechanisms and systems to operate in a cryogenic environment are discussed. The focal point for the entire engineering effort was the design of the National Transonic Facility, which is a closed-circuit cryogenic wind tunnel. The papers covered a variety of mechanical, structural, and systems design subjects including thermal structures insulation systems, noise, seals, and materials.

The History of the Planar Elastica: Insights into Mechanics and Scientific Method

NASA Astrophysics Data System (ADS)

Goss, Victor Geoffrey Alan

2009-08-01

Euler’s formula for the buckling of an elastic column is widely used in engineering design. However, only a handful of engineers will be familiar with Euler’s classic paper De Curvis Elasticis in which the formula is derived. In addition to the Euler Buckling Formula, De Curvis Elasticis classifies all the bent configurations of elastic rod—a landmark in the development of a rational theory of continuum mechanics. As a historical case study, Euler’s work on elastic rods offers an insight into some important concepts which underlie mechanics. It sheds light on the search for unifying principles of mechanics and the role of analysis. The connection between results obtained from theory and those obtained from experiments on rods, highlights two different approaches to scientific discovery, which can be traced back to Bacon, Descartes and Galileo. The bent rod also has an analogy in dynamics, with a pendulum, which highlights the crucial distinctions between initial value and boundary value problems and between linear and nonlinear differential equations. In addition to benefiting from the overview which a historical study provides, the particular problem of the elastica offers students of science and engineering a clear elucidation of the connection between mathematics and real-world engineering, issues which still have relevance today.

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.

Reverse engineering and identification in systems biology: strategies, perspectives and challenges

PubMed Central

Villaverde, Alejandro F.; Banga, Julio R.

2014-01-01

The interplay of mathematical modelling with experiments is one of the central elements in systems biology. The aim of reverse engineering is to infer, analyse and understand, through this interplay, the functional and regulatory mechanisms of biological systems. Reverse engineering is not exclusive of systems biology and has been studied in different areas, such as inverse problem theory, machine learning, nonlinear physics, (bio)chemical kinetics, control theory and optimization, among others. However, it seems that many of these areas have been relatively closed to outsiders. In this contribution, we aim to compare and highlight the different perspectives and contributions from these fields, with emphasis on two key questions: (i) why are reverse engineering problems so hard to solve, and (ii) what methods are available for the particular problems arising from systems biology? PMID:24307566

Centrifugal pumps for rocket engines

NASA Technical Reports Server (NTRS)

Campbell, W. E.; Farquhar, J.

1974-01-01

The use of centrifugal pumps for rocket engines is described in terms of general requirements of operational and planned systems. Hydrodynamic and mechanical design considerations and techniques and test procedures are summarized. Some of the pump development experiences, in terms of both problems and solutions, are highlighted.

Linear elastic fracture mechanics primer

NASA Technical Reports Server (NTRS)

Wilson, Christopher D.

1992-01-01

This primer is intended to remove the blackbox perception of fracture mechanics computer software by structural engineers. The fundamental concepts of linear elastic fracture mechanics are presented with emphasis on the practical application of fracture mechanics to real problems. Numerous rules of thumb are provided. Recommended texts for additional reading, and a discussion of the significance of fracture mechanics in structural design are given. Griffith's criterion for crack extension, Irwin's elastic stress field near the crack tip, and the influence of small-scale plasticity are discussed. Common stress intensities factor solutions and methods for determining them are included. Fracture toughness and subcritical crack growth are discussed. The application of fracture mechanics to damage tolerance and fracture control is discussed. Several example problems and a practice set of problems are given.

Volterra-series-based nonlinear system modeling and its engineering applications: A state-of-the-art review

NASA Astrophysics Data System (ADS)

Cheng, C. M.; Peng, Z. K.; Zhang, W. M.; Meng, G.

2017-03-01

Nonlinear problems have drawn great interest and extensive attention from engineers, physicists and mathematicians and many other scientists because most real systems are inherently nonlinear in nature. To model and analyze nonlinear systems, many mathematical theories and methods have been developed, including Volterra series. In this paper, the basic definition of the Volterra series is recapitulated, together with some frequency domain concepts which are derived from the Volterra series, including the general frequency response function (GFRF), the nonlinear output frequency response function (NOFRF), output frequency response function (OFRF) and associated frequency response function (AFRF). The relationship between the Volterra series and other nonlinear system models and nonlinear problem solving methods are discussed, including the Taylor series, Wiener series, NARMAX model, Hammerstein model, Wiener model, Wiener-Hammerstein model, harmonic balance method, perturbation method and Adomian decomposition. The challenging problems and their state of arts in the series convergence study and the kernel identification study are comprehensively introduced. In addition, a detailed review is then given on the applications of Volterra series in mechanical engineering, aeroelasticity problem, control engineering, electronic and electrical engineering.

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.

Dissolving the engineering moral dilemmas within the Islamic ethico-legal praxes.

PubMed

Solihu, Abdul Kabir Hussain; Ambali, Abdul Rauf

2011-03-01

The goal of responsible engineers is the creation of useful and safe technological products and commitment to public health, while respecting the autonomy of the clients and the public. Because engineers often face moral dilemma to resolve such issues, different engineers have chosen different course of actions depending on their respective moral value orientations. Islam provides a value-based mechanism rooted in the Maqasid al-Shari'ah (the objectives of Islamic law). This mechanism prioritizes some values over others and could help resolve the moral dilemmas faced in engineering. This paper introduces the Islamic interpretive-evaluative maxims to two core issues in engineering ethics: genetically modified foods and whistleblowing. The study aims primarily to provide problem-solving maxims within the Maqasid al-Shari'ah matrix through which such moral dilemmas in science and engineering could be studied and resolved.

[Mechanical strength and mechano-compatibility of tissue-engineered bones].

PubMed

Tanaka, Shigeo

2016-01-01

Current artificial bones made of metals and ceramics may be replaced around a decade after implantation due to its low durability, which is brought on by a large difference from the host bone in mechanical properties, i.e., low mechano-compatibility. On the other hand, tissue engineering could be a solution with regeneration of bone tissues from stem cells in vitro. However, there are still some problems to realize exactly the same mechanical properties as those of real bone. This paper introduces the technical background of bone tissue engineering and discusses possible methods for installation of mechano-compatibility into a regenerative bone. At the end, future directions toward the realization of ideal mechano-compatible regenerative bone are proposed.

Forensic engineering: applying materials and mechanics principles to the investigation of product failures.

PubMed

Hainsworth, S V; Fitzpatrick, M E

2007-06-01

Forensic engineering is the application of engineering principles or techniques to the investigation of materials, products, structures or components that fail or do not perform as intended. In particular, forensic engineering can involve providing solutions to forensic problems by the application of engineering science. A criminal aspect may be involved in the investigation but often the problems are related to negligence, breach of contract, or providing information needed in the redesign of a product to eliminate future failures. Forensic engineering may include the investigation of the physical causes of accidents or other sources of claims and litigation (for example, patent disputes). It involves the preparation of technical engineering reports, and may require giving testimony and providing advice to assist in the resolution of disputes affecting life or property.This paper reviews the principal methods available for the analysis of failed components and then gives examples of different component failure modes through selected case studies.

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.

Dynamical mechanism in aero-engine gas path system using minimum spanning tree and detrended cross-correlation analysis

NASA Astrophysics Data System (ADS)

Dong, Keqiang; Zhang, Hong; Gao, You

2017-01-01

Identifying the mutual interaction in aero-engine gas path system is a crucial problem that facilitates the understanding of emerging structures in complex system. By employing the multiscale multifractal detrended cross-correlation analysis method to aero-engine gas path system, the cross-correlation characteristics between gas path system parameters are established. Further, we apply multiscale multifractal detrended cross-correlation distance matrix and minimum spanning tree to investigate the mutual interactions of gas path variables. The results can infer that the low-spool rotor speed (N1) and engine pressure ratio (EPR) are main gas path parameters. The application of proposed method contributes to promote our understanding of the internal mechanisms and structures of aero-engine dynamics.

Flipping Core Courses in the Undergraduate Mechanical Engineering Curriculum: Heat Transfer

ERIC Educational Resources Information Center

Schrlau, Michael G.; Stevens, Robert J.; Schley, Sara

2016-01-01

Flipped classrooms support learner-centered approaches to improve conceptualization, comprehension, and problem solving skills by delivering content outside the classroom and actively engaging students inside the classroom. While literature in engineering and science education supports and encourages the use of inverted instruction, many core…

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…

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.

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

Mechanical design problems associated with turbopump fluid film bearings

NASA Technical Reports Server (NTRS)

Evces, Charles R.

1990-01-01

Most high speed cryogenic turbopumps for liquid propulsion rocket engines currently use ball or roller contact bearings for rotor support. The operating speeds, loads, clearances, and environments of these pumps combine to make bearing wear a limiting factor on turbopump life. An example is the high pressure oxygen turbopump (HPOTP) used in the Space Shuttle Main Engine (SSME). Although the HPOTP design life is 27,000 seconds at 30,000 rpms, or approximately 50 missions, bearings must currently be replaced after 2 missions. One solution to the bearing wear problem in the HPOTP, as well as in future turbopump designs, is the utilization of fluid film bearings in lieu of continuous contact bearings. Hydrostatic, hydrodynamic, and damping seal bearings are all replacement candidates for contact bearings in rocket engine high speed turbomachinery. These three types of fluid film bearings have different operating characteristics, but they share a common set of mechanical design opportunities and difficulties. Results of research to define some of the mechanical design issues are given. Problems considered include transient strat/stop rub, non-operational rotor support, bearing wear inspection and measurement, and bearing fluid supply route. Emphasis is given to the HPOTP preburner pump (PBP) bearing, but the results are pertinent to high-speed cryogenic turbomachinery in general.

Analysis of small crack behavior for airframe applications

NASA Technical Reports Server (NTRS)

Mcclung, R. C.; Chan, K. S.; Hudak, S. J., Jr.; Davidson, D. L.

1994-01-01

The small fatigue crack problem is critically reviewed from the perspective of airframe applications. Different types of small cracks-microstructural, mechanical, and chemical-are carefully defined and relevant mechanisms identified. Appropriate analysis techniques, including both rigorous scientific and practical engineering treatments, are briefly described. Important materials data issues are addressed, including increased scatter in small crack data and recommended small crack test methods. Key problems requiring further study are highlighted.

Innovating Method of Existing Mechanical Product Based on TRIZ Theory

NASA Astrophysics Data System (ADS)

Zhao, Cunyou; Shi, Dongyan; Wu, Han

Main way of product development is adaptive design and variant design based on existing product. In this paper, conceptual design frame and its flow model of innovating products is put forward through combining the methods of conceptual design and TRIZ theory. Process system model of innovating design that includes requirement analysis, total function analysis and decomposing, engineering problem analysis, finding solution of engineering problem and primarily design is constructed and this establishes the base for innovating design of existing product.

NASA/USRA advanced design program activity, 1991-1992

NASA Astrophysics Data System (ADS)

Dorrity, J. Lewis; Patel, Suneer

The School of Textile and Fiber Engineering continued to pursue design projects with the Mechanical Engineering School giving the students an outstanding opportunity to interact with students from another discipline. Four problems were defined which had aspects which would be reasonably assigned to an interdisciplinary team. The design problems are described. The projects included lunar preform manufacturing, dust control for Enabler, an industrial sewing machine variable speed controllor, Enabler operation station, and design for producing fiberglass fabric in a lunar environment.

NASA/USRA advanced design program activity, 1991-1992

NASA Technical Reports Server (NTRS)

Dorrity, J. Lewis; Patel, Suneer

1992-01-01

The School of Textile and Fiber Engineering continued to pursue design projects with the Mechanical Engineering School giving the students an outstanding opportunity to interact with students from another discipline. Four problems were defined which had aspects which would be reasonably assigned to an interdisciplinary team. The design problems are described. The projects included lunar preform manufacturing, dust control for Enabler, an industrial sewing machine variable speed controllor, Enabler operation station, and design for producing fiberglass fabric in a lunar environment.

Special Section dedicated to the 11th International Conference on Vibration Problems (ICOVP-2013)

NASA Astrophysics Data System (ADS)

Dimitrovová, Zuzana; Gonçalves, Rodrigo

2015-01-01

This section contains the first set of selected papers from the 11th edition of the biennial International Conference series on Vibration Problems (ICOVP-2013), which was held at the Instituto Superior Técnico in Lisbon, Portugal, on 9-12 September 2013, and was jointly organized by the Civil Engineering Department of the Universidade Nova de Lisboa and the Institute of Mechanical Engineering at the Instituto Superior Técnico. A second set of papers will be included in a forthcoming issue.

Making the EZ Choice

NASA Technical Reports Server (NTRS)

2001-01-01

Analytical Mechanics Associates, Inc. (AMA), of Hampton, Virginia, created the EZopt software application through Small Business Innovation Research (SBIR) funding from NASA's Langley Research Center. The new software is a user-friendly tool kit that provides quick and logical solutions to complex optimal control problems. In its most basic form, EZopt converts process data into math equations and then proceeds to utilize those equations to solve problems within control systems. EZopt successfully proved its advantage when applied to short-term mission planning and onboard flight computer implementation. The technology has also solved multiple real-life engineering problems faced in numerous commercial operations. For instance, mechanical engineers use EZopt to solve control problems with robots, while chemical plants implement the application to overcome situations with batch reactors and temperature control. In the emerging field of commercial aerospace, EZopt is able to optimize trajectories for launch vehicles and perform potential space station- keeping tasks. Furthermore, the software also helps control electromagnetic devices in the automotive industry.

Creative brains: designing in the real world†

PubMed Central

Goel, Vinod

2014-01-01

The process of designing artifacts is a creative activity. It is proposed that, at the cognitive level, one key to understanding design creativity is to understand the array of symbol systems designers utilize. These symbol systems range from being vague, imprecise, abstract, ambiguous, and indeterminate (like conceptual sketches), to being very precise, concrete, unambiguous, and determinate (like contract documents). The former types of symbol systems support associative processes that facilitate lateral (or divergent) transformations that broaden the problem space, while the latter types of symbol systems support inference processes facilitating vertical (or convergent) transformations that deepen of the problem space. The process of artifact design requires the judicious application of both lateral and vertical transformations. This leads to a dual mechanism model of design problem-solving comprising of an associative engine and an inference engine. It is further claimed that this dual mechanism model is supported by an interesting hemispheric dissociation in human prefrontal cortex. The associative engine and neural structures that support imprecise, ambiguous, abstract, indeterminate representations are lateralized in the right prefrontal cortex, while the inference engine and neural structures that support precise, unambiguous, determinant representations are lateralized in the left prefrontal cortex. At the brain level, successful design of artifacts requires a delicate balance between the two hemispheres of prefrontal cortex. PMID:24817846

On-Board Real-Time Optimization Control for Turbo-Fan Engine Life Extending

NASA Astrophysics Data System (ADS)

Zheng, Qiangang; Zhang, Haibo; Miao, Lizhen; Sun, Fengyong

2017-11-01

A real-time optimization control method is proposed to extend turbo-fan engine service life. This real-time optimization control is based on an on-board engine mode, which is devised by a MRR-LSSVR (multi-input multi-output recursive reduced least squares support vector regression method). To solve the optimization problem, a FSQP (feasible sequential quadratic programming) algorithm is utilized. The thermal mechanical fatigue is taken into account during the optimization process. Furthermore, to describe the engine life decaying, a thermal mechanical fatigue model of engine acceleration process is established. The optimization objective function not only contains the sub-item which can get fast response of the engine, but also concludes the sub-item of the total mechanical strain range which has positive relationship to engine fatigue life. Finally, the simulations of the conventional optimization control which just consider engine acceleration performance or the proposed optimization method have been conducted. The simulations demonstrate that the time of the two control methods from idle to 99.5 % of the maximum power are equal. However, the engine life using the proposed optimization method could be surprisingly increased by 36.17 % compared with that using conventional optimization control.

Workshop on the Mechanics of Ice and Its Applications

DTIC Science & Technology

1993-10-01

Academy of Sciences Institute Moscow, USSR Leningrad, USSR V.P. Epifanov B.G. Korenev Institute for Problems in Mechanics Moscow Civil Engineering...Related to the Static Strength of Ice Cover Speakers: B.G. Korenev and E.B. Koreneva 10:30 - 11:00 The Mechanics of Pressure Ridge Building from a Wide

Solving ordinary differential equations by electrical analogy: a multidisciplinary teaching tool

NASA Astrophysics Data System (ADS)

Sanchez Perez, J. F.; Conesa, M.; Alhama, I.

2016-11-01

Ordinary differential equations are the mathematical formulation for a great variety of problems in science and engineering, and frequently, two different problems are equivalent from a mathematical point of view when they are formulated by the same equations. Students acquire the knowledge of how to solve these equations (at least some types of them) using protocols and strict algorithms of mathematical calculation without thinking about the meaning of the equation. The aim of this work is that students learn to design network models or circuits in this way; with simple knowledge of them, students can establish the association of electric circuits and differential equations and their equivalences, from a formal point of view, that allows them to associate knowledge of two disciplines and promote the use of this interdisciplinary approach to address complex problems. Therefore, they learn to use a multidisciplinary tool that allows them to solve these kinds of equations, even students of first course of engineering, whatever the order, grade or type of non-linearity. This methodology has been implemented in numerous final degree projects in engineering and science, e.g., chemical engineering, building engineering, industrial engineering, mechanical engineering, architecture, etc. Applications are presented to illustrate the subject of this manuscript.

Computational and analytical methods in nonlinear fluid dynamics

NASA Astrophysics Data System (ADS)

Walker, James

1993-09-01

The central focus of the program was on the application and development of modern analytical and computational methods to the solution of nonlinear problems in fluid dynamics and reactive gas dynamics. The research was carried out within the Division of Engineering Mathematics in the Department of Mechanical Engineering and Mechanics and principally involved Professors P.A. Blythe, E. Varley and J.D.A. Walker. In addition. the program involved various international collaborations. Professor Blythe completed work on reactive gas dynamics with Professor D. Crighton FRS of Cambridge University in the United Kingdom. Professor Walker and his students carried out joint work with Professor F.T. Smith, of University College London, on various problems in unsteady flow and turbulent boundary layers.

The research and practice of spacecraft software engineering

NASA Astrophysics Data System (ADS)

Chen, Chengxin; Wang, Jinghua; Xu, Xiaoguang

2017-06-01

In order to ensure the safety and reliability of spacecraft software products, it is necessary to execute engineering management. Firstly, the paper introduces the problems of unsystematic planning, uncertain classified management and uncontinuous improved mechanism in domestic and foreign spacecraft software engineering management. Then, it proposes a solution for software engineering management based on system-integrated ideology in the perspective of spacecraft system. Finally, a application result of spacecraft is given as an example. The research can provides a reference for executing spacecraft software engineering management and improving software product quality.

Podcasting in Engineering Education: A Preliminary Study of Content, Student Attitudes, and Impact

ERIC Educational Resources Information Center

Berger, Edward

2007-01-01

Edward Berger describes a pilot project implemented in an undergraduate engineering mechanics course, entitled Strength of Materials to investigate whether and how students would perceive a benefit from podcasting as a pedagogical tool. Three types of podcasting content were produced: (a) video problem solutions, (b) roundtable discussions, and…

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.

Nonlinear mechanical behavior of thermoplastic matrix materials for advanced composites

NASA Technical Reports Server (NTRS)

Arenz, R. J.; Landel, R. F.

1989-01-01

Two recent theories of nonlinear mechanical response are quantitatively compared and related to experimental data. Computer techniques are formulated to handle the numerical integration and iterative procedures needed to solve the associated sets of coupled nonlinear differential equations. Problems encountered during these formulations are discussed and some open questions described. Bearing in mind these cautions, the consequences of changing parameters that appear in the formulations on the resulting engineering properties are discussed. Hence, engineering approaches to the analysis of thermoplastic matrix material can be suggested.

Integrated orbital servicing study follow-on. Volume 3: Engineering test unit and controls

NASA Technical Reports Server (NTRS)

1978-01-01

A one-g servicing demonstration system which can be used to investigate and develop, in a real time hands-on situation, a wide variety of the mechanism and control system aspects of orbital servicing in the form of module exchange is described including the engineering test unit and the servicer servo drive console. A series of recommendations for future work is given concerning the control problem and more efficient module exchanges, mechanical elements, and electronics.

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

PubMed

Luz, Taciana Ramos; Echternacht, Eliza Helena de Oliveira

2012-01-01

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

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

Slattery, Stuart R

ExaMPM is a mini-application for the Material Point Method (MPM) for studying the application of MPM to future exascale computing systems. MPM is a general method for computational mechanics and fluids and is used in a wide variety of science and engineering disciplines to study problems with large deformations, phase change, fracture, and other phenomena. ExaMPM provides a reference implementation of MPM as described in the 1994 work of Sulsky et.al. (Sulsky, Deborah, Zhen Chen, and Howard L. Schreyer. "A particle method for history-dependent materials." Computer methods in applied mechanics and engineering 118.1-2 (1994): 179-196.). The software can solve basicmore » MPM problems in solid mechanics using the original algorithm of Sulsky with explicit time integration, basic geometries, and free-slip and no-slip boundary conditions as described in the reference. ExaMPM is intended to be used as a starting point to design new parallel algorithms for the next generation of DOE supercomputers.« less

46 CFR 54.30-3 - Introduction.

Code of Federal Regulations, 2010 CFR

2010-10-01

... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Mechanical Stress... petroleum and natural gases, at “low temperatures” may often be difficult to thermally stress relieve. Where no other problem, such as corrosion exists, mechanical stress relief will be permitted for Class II-L...

46 CFR 54.30-3 - Introduction.

Code of Federal Regulations, 2014 CFR

2014-10-01

... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Mechanical Stress... petroleum and natural gases, at “low temperatures” may often be difficult to thermally stress relieve. Where no other problem, such as corrosion exists, mechanical stress relief will be permitted for Class II-L...

46 CFR 54.30-3 - Introduction.

Code of Federal Regulations, 2013 CFR

2013-10-01

... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Mechanical Stress... petroleum and natural gases, at “low temperatures” may often be difficult to thermally stress relieve. Where no other problem, such as corrosion exists, mechanical stress relief will be permitted for Class II-L...

46 CFR 54.30-3 - Introduction.

Code of Federal Regulations, 2012 CFR

2012-10-01

... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Mechanical Stress... petroleum and natural gases, at “low temperatures” may often be difficult to thermally stress relieve. Where no other problem, such as corrosion exists, mechanical stress relief will be permitted for Class II-L...

46 CFR 54.30-3 - Introduction.

Code of Federal Regulations, 2011 CFR

2011-10-01

... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Mechanical Stress... petroleum and natural gases, at “low temperatures” may often be difficult to thermally stress relieve. Where no other problem, such as corrosion exists, mechanical stress relief will be permitted for Class II-L...

Attracting Students to Fluid Mechanics with Coffee

NASA Astrophysics Data System (ADS)

Ristenpart, William

2016-11-01

We describe a new class developed at U.C. Davis titled "The Design of Coffee," which serves as a nonmathematical introduction to chemical engineering as illustrated by the process of roasting and brewing coffee. Hands-on coffee experiments demonstrate key engineering principles, including material balances, chemical kinetics, mass transfer, conservation of energy, and fluid mechanics. The experiments lead to an engineering design competition where students strive to make the best tasting coffee using the least amount of energy - a classic engineering optimization problem, but one that is both fun and tasty. "The Design of Coffee" started as a freshmen seminar in 2013, and it has exploded in popularity: it now serves 1,533 students per year, and is the largest and most popular elective course at U.C. Davis. In this talk we focus on the class pedagogy as applied to fluid mechanics, with an emphasis on how coffee serves as an engaging and exciting topic for teaching students about fluid mechanics in an approachable, hands-on manner.

Modeling and simulation of different and representative engineering problems using Network Simulation Method

PubMed Central

2018-01-01

Mathematical models simulating different and representative engineering problem, atomic dry friction, the moving front problems and elastic and solid mechanics are presented in the form of a set of non-linear, coupled or not coupled differential equations. For different parameters values that influence the solution, the problem is numerically solved by the network method, which provides all the variables of the problems. Although the model is extremely sensitive to the above parameters, no assumptions are considered as regards the linearization of the variables. The design of the models, which are run on standard electrical circuit simulation software, is explained in detail. The network model results are compared with common numerical methods or experimental data, published in the scientific literature, to show the reliability of the model. PMID:29518121

Modeling and simulation of different and representative engineering problems using Network Simulation Method.

PubMed

Sánchez-Pérez, J F; Marín, F; Morales, J L; Cánovas, M; Alhama, F

2018-01-01

Mathematical models simulating different and representative engineering problem, atomic dry friction, the moving front problems and elastic and solid mechanics are presented in the form of a set of non-linear, coupled or not coupled differential equations. For different parameters values that influence the solution, the problem is numerically solved by the network method, which provides all the variables of the problems. Although the model is extremely sensitive to the above parameters, no assumptions are considered as regards the linearization of the variables. The design of the models, which are run on standard electrical circuit simulation software, is explained in detail. The network model results are compared with common numerical methods or experimental data, published in the scientific literature, to show the reliability of the model.

Aerospace Mechanisms and Tribology Technology: Case Study

NASA Technical Reports Server (NTRS)

Miyoshi, K.

1999-01-01

This paper focuses attention on tribology technology practice related to vacuum tribology. A case study describes an aspect of a real problem in sufficient detail for the engineer and scientist to understand the tribological situation and the failure. The nature of the problem is analyzed and the tribological properties are examined.

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

PubMed

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

2018-03-01

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

Statistical mechanics of budget-constrained auctions

NASA Astrophysics Data System (ADS)

Altarelli, F.; Braunstein, A.; Realpe-Gomez, J.; Zecchina, R.

2009-07-01

Finding the optimal assignment in budget-constrained auctions is a combinatorial optimization problem with many important applications, a notable example being in the sale of advertisement space by search engines (in this context the problem is often referred to as the off-line AdWords problem). On the basis of the cavity method of statistical mechanics, we introduce a message-passing algorithm that is capable of solving efficiently random instances of the problem extracted from a natural distribution, and we derive from its properties the phase diagram of the problem. As the control parameter (average value of the budgets) is varied, we find two phase transitions delimiting a region in which long-range correlations arise.

Liquid rocket engine centrifugal flow turbopumps. [design criteria

NASA Technical Reports Server (NTRS)

1973-01-01

Design criteria and recommended practices are discussed for the following configurations selected from the design sequence of a liquid rocket engine centrifugal flow turbopump: (1) pump performance including speed, efficiency, and flow range; (2) impeller; (3) housing; and (4) thrust balance system. Hydrodynamic, structural, and mechanical problems are addressed for the achievement of required pump performance within the constraints imposed by the engine/turbopump system. Materials and fabrication specifications are also discussed.

Quantum Mechanics - Fundamentals and Applications to Technology

NASA Astrophysics Data System (ADS)

Singh, Jasprit

1996-10-01

Explore the relationship between quantum mechanics and information-age applications This volume takes an altogether unique approach to quantum mechanics. Providing an in-depth exposition of quantum mechanics fundamentals, it shows how these concepts are applied to most of today's information technologies, whether they are electronic devices or materials. No other text makes this critical, essential leap from theory to real-world applications. The book's lively discussion of the mathematics involved fits right in with contemporary multidisciplinary trends in education: Once the basic formulation has been derived in a given chapter, the connection to important technological problems is summarily described. The many helpful features include * Twenty-eight application-oriented sections that focus on lasers, transistors, magnetic memories, superconductors, nuclear magnetic resonance (NMR), and other important technology-driving materials and devices * One hundred solved examples, with an emphasis on numerical results and the connection between the physics and its applications * End-of-chapter problems that ground the student in both fundamental and applied concepts * Numerous figures and tables to clarify the various topics and provide a global view of the problems under discussion * Over two hundred illustrations to highlight problems and text A book for the information age, Quantum Mechanics: Fundamentals and Applications to Technology promises to become a standard in departments of electrical engineering, applied physics, and materials science, as well as physics. It is an excellent text for senior undergraduate and graduate students, and a helpful reference for practicing scientists, engineers, and chemists in the semiconductor and electronic industries.

Hierarchy curriculum for practical skills training in optics and photonics

NASA Astrophysics Data System (ADS)

Zheng, XiaoDong; Wang, XiaoPing; Liu, Xu; Liu, XiangDong; Lin, YuanFang

2017-08-01

The employers in optical engineering fields hope to recruit students who are capable of applying optical principles to solve engineering problems and have strong laboratory skills. In Zhejiang University, a hierarchy curriculum for practical skill training has been constructed to satisfy this demand. This curriculum includes "Introductive practicum" for freshmen, "Opto-mechanical systems design", "Engineering training", "Electronic system design", "Student research training program (SRTP)", "National University Students' Optical-Science-Technology Competition game", and "Offcampus externship". Without cutting optical theory credit hours, this hierarchy curriculum provides a step-by-step solution to enhance students' practical skills. By following such a hierarchy curriculum, students can smoothly advance from a novice to a qualified professional expert in optics. They will be able to utilize optical engineering tools to design, build, analyze, improve, and test systems, and will be able to work effectively in teams to solve problems in engineering and design.

Vertical Stream Curricula Integration of Problem-Based Learning Using an Autonomous Vacuum Robot in a Mechatronics Course

ERIC Educational Resources Information Center

Chin, Cheng; Yue, Keng

2011-01-01

Difficulties in teaching a multi-disciplinary subject such as the mechatronics system design module in Departments of Mechatronics Engineering at Temasek Polytechnic arise from the gap in experience and skill among staff and students who have different backgrounds in mechanical, computer and electrical engineering within the Mechatronics…

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.

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 a lunar photolithoautotroph to thrive on the moon - life or simulacrum?

NASA Astrophysics Data System (ADS)

Ellery, A. A.

2018-07-01

Recent work in developing self-replicating machines has approached the problem as an engineering problem, using engineering materials and methods to implement an engineering analogue of a hitherto uniquely biological function. The question is - can anything be learned that might be relevant to an astrobiological context in which the problem is to determine the general form of biology independent of the Earth. Compared with other non-terrestrial biology disciplines, engineered life is more demanding. Engineering a self-replicating machine tackles real environments unlike artificial life which avoids the problem of physical instantiation altogether by examining software models. Engineering a self-replicating machine is also more demanding than synthetic biology as no library of functional components exists. Everything must be constructed de novo. Biological systems already have the capacity to self-replicate but no engineered machine has yet been constructed with the same ability - this is our primary goal. On the basis of the von Neumann analysis of self-replication, self-replication is a by-product of universal construction capability - a universal constructor is a machine that can construct anything (in a functional sense) given the appropriate instructions (DNA/RNA), energy (ATP) and materials (food). In the biological cell, the universal construction mechanism is the ribosome. The ribosome is a biological assembly line for constructing proteins while DNA constitutes a design specification. For a photoautotroph, the energy source is ambient and the food is inorganic. We submit that engineering a self-replicating machine opens up new areas of astrobiology to be explored in the limits of life.

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.

A continuing program for technology transfer to the apparel industry

NASA Technical Reports Server (NTRS)

Clingman, W. H.

1971-01-01

A six month program has been carried out to investigate various mechanisms for transferring technology to industry. This program has focused on transfer to the apparel industry through the Apparel Research Foundation. The procedure was to analyze the problem, obtain potentially relevant aerospace technology, and then transfer this technology to the industry organization. This was done in a specific case. Technology was identified relevant to stitchless joining, and this technology was transferred to the Apparel Research Foundation. The feasibility and ground rules for carrying out such activities on a broader scale were established. A specific objective was to transfer new technology from the industry organization to the industry itself. This required the establishment of an application engineering program. Another transfer mechanism tested was publication of solutions to industry problems in a format familiar to the industry. This is to be distinguished from circulating descriptions of new technology. Focus is on the industry problem and the manager is given a formula for solving it that he can follow. It was concluded that this mechanism can complement the problem statement approach to technology transfer. It is useful in achieving transfer when a large amount of application engineering is not necessary. A wide audience is immediately exposed to the technology. On the other hand, the major manufacturing problems which require a sophisticated technical solution integrating many innovations are less likely to be helped.

Enhancing the Connection to Undergraduate Engineering Students: A Hands-On and Team-Based Approach to Fluid Mechanics

ERIC Educational Resources Information Center

Wei, Tie; Ford, Julie

2015-01-01

This article provides information about the integration of innovative hands-on activities within a sophomore-level Fluid Mechanics course at New Mexico Tech. The course introduces students to the fundamentals of fluid mechanics with emphasis on teaching key equations and methods of analysis for solving real-world problems. Strategies and examples…

Celestial mechanics during the last two decades

NASA Technical Reports Server (NTRS)

Szebehely, V.

1978-01-01

The unprecedented progress in celestial mechanics (orbital mechanics, astrodynamics, space dynamics) is reviewed from 1957 to date. The engineering, astronomical and mathematical aspects are synthesized. The measuring and computational techniques developed parallel with the theoretical advances are outlined. Major unsolved problem areas are listed with proposed approaches for their solutions. Extrapolations and predictions of the progress for the future conclude the paper.

Review of problems in application of supersonic combustion

NASA Technical Reports Server (NTRS)

Ferri, A.

1977-01-01

The problem of air-breathing engines capable of flying at very high Mach numbers is described briefly. Possible performance of supersonic combustion ramjets is outlined briefly and the supersonic combustion process is described. Two mechanisms of combustion are outlined: one is supersonic combustion controlled by convection process, and the second is controlled by diffusion. The parameters related to the combustion process are discussed in detail. Data and analyses of reaction rates and mixing phenomena are represented; the flame mechanism is discussed, and experimental results are presented.

Ways of thinking about and teaching ethical problem solving: microethics and macroethics in engineering.

PubMed

Herkert, Joseph R

2005-07-01

Engineering ethics entails three frames of reference: individual, professional, and social. "Microethics" considers individuals and internal relations of the engineering profession; "macroethics" applies to the collective social responsibility of the profession and to societal decisions about technology. Most research and teaching in engineering ethics, including online resources, has had a "micro" focus. Mechanisms for incorporating macroethical perspectives include: integrating engineering ethics and science, technology and society (STS); closer integration of engineering ethics and computer ethics; and consideration of the influence of professional engineering societies and corporate social responsibility programs on ethical engineering practice. Integrating macroethical issues and concerns in engineering ethics involves broadening the context of ethical problem solving. This in turn implies: developing courses emphasizing both micro and macro perspectives, providing faculty development that includes training in both STS and practical ethics; and revision of curriculum materials, including online resources. Multidisciplinary collaboration is recommended 1) to create online case studies emphasizing ethical decision making in individual, professional, and societal contexts; 2) to leverage existing online computer ethics resources with relevance to engineering education and practice; and 3) to create transparent linkages between public policy positions advocated by professional societies and codes of ethics.

Can Interactive Web-Based CAD Tools Improve the Learning of Engineering Drawing? A Case Study

ERIC Educational Resources Information Center

Pando Cerra, Pablo; Suárez González, Jesús M.; Busto Parra, Bernardo; Rodríguez Ortiz, Diana; Álvarez Peñín, Pedro I.

2014-01-01

Many current Web-based learning environments facilitate the theoretical teaching of a subject but this may not be sufficient for those disciplines that require a significant use of graphic mechanisms to resolve problems. This research study looks at the use of an environment that can help students learn engineering drawing with Web-based CAD…

Instructor's Guide for Fluid Mechanics: A Modular Approach.

ERIC Educational Resources Information Center

Cox, John S.

This guide is designed to assist engineering teachers in developing an understanding of fluid mechanics in their students. The course is designed around a set of nine self-paced learning modules, each of which contains a discussion of the subject matter; incremental objectives; problem index, set and answers; resource materials; and a quiz with…

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.

Aerospace Mechanisms and Tribology Technology: Case Studies

NASA Technical Reports Server (NTRS)

Miyoshi, Kazuhisa

1999-01-01

This chapter focuses attention on tribology technology practice related to vacuum tribology and space tribology. Two case studies describe aspects of real problems in sufficient detail for the engineer and the scientist to understand the tribological situations and the failures. The nature of the problems is analyzed and the range of potential solutions is evaluated. Courses of action are recommended.

Formula student as part of a mechanical engineering curriculum

NASA Astrophysics Data System (ADS)

Davies, Huw Charles

2013-10-01

Formula Student (FS) is a multi-university student design competition managed by the UK Institution of Mechanical Engineers. Students are required to demonstrate and prove their creativity and engineering skills through the design, manufacture and financing of a small formula style race car. This paper seeks to explore the educational value that derives from the FS activity through a series of semi-structured interviews with key stakeholders. Through the analysis of the interview data, it was found that the FS activity supported development of student skills and competencies in the following areas: use of engineering knowledge to support the application of existing and emerging technology; application of theoretical and practical knowledge to the solution of engineering problems; development of technical and commercial management skills; development of effective interpersonal skills, including communication skills; and demonstration of personal commitment to professional development. In addition, a number of areas for implementing 'good practise' have been identified. The information herein supports educators in their responsibility to help meet the needs of the engineering industry for high quality graduates.

Effects of Using Graphics and Animation Online Problem-Based Learning on Visualization Skills among Students

NASA Astrophysics Data System (ADS)

Ariffin, A.; Samsudin, M. A.; Zain, A. N. Md.; Hamzah, N.; Ismail, M. E.

2017-05-01

The Engineering Drawing subject develops skills in geometry drawing becoming more professional. For the concept in Engineering Drawing, students need to have good visualization skills. Visualization is needed to help students get a start before translating into a drawing. So that, Problem Based Learning (PBL) using animation mode (PBL-A) and graphics mode (PBL-G) will be implemented in class. Problem-solving process is repeatedly able to help students interpret engineering drawings step work correctly and accurately. This study examined the effects of PBL-A online and PBL-G online on visualization skills of students in polytechnics. Sixty eight mechanical engineering students have been involved in this study. The visualization test adapted from Bennett, Seashore and Wesman was used in this study. Results showed significant differences in mean scores post-test of visualization skills among the students enrolled in PBL-G with the group of students who attended PBL-A online after effects of pre-test mean score is controlled. Therefore, the effects of animation modes have a positive impact on increasing students’ visualization skills.

Microelectrical Mechanical Systems Flow Control Used to Manage Engine Face Distortion in Compact Inlet Systems

NASA Technical Reports Server (NTRS)

Anderson, Bernhard H.; Miller, Daniel N.

1999-01-01

Turbofan engine-face flow distortion is one of the most troublesome and least understood problems for designers of modern engine inlet systems. One concern is that there are numerous sources of flow-field distortion that are ingested by the inlet or generated within the inlet duct itself. Among these are: (1) flow separation at the cowl lip during in-flight maneuvering, (2) flow separation on the compression surfaces due to shock-wave/boundary layer interactions, (3) spillage of the fuselage boundary layer into the inlet duct, (4) ingestion of aircraft vortices and wakes emanating from upstream disturbances, and (5) strong secondary flow gradients and flow separation induced by wall curvature within the inlet duct itself. Most developing aircraft (including the B70, F-111, F-14, Mig-25, Tornado, and Airbus A300) have experienced one or more of these types of problems, particularly at high Mach numbers and/or extreme maneuver conditions when flow distortion at the engine face exceeded the allowable limits of the engine.

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

PubMed

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

2014-03-01

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

Structural dynamics verification facility study

NASA Technical Reports Server (NTRS)

Kiraly, L. J.; Hirchbein, M. S.; Mcaleese, J. M.; Fleming, D. P.

1981-01-01

The need for a structural dynamics verification facility to support structures programs was studied. Most of the industry operated facilities are used for highly focused research, component development, and problem solving, and are not used for the generic understanding of the coupled dynamic response of major engine subsystems. Capabilities for the proposed facility include: the ability to both excite and measure coupled structural dynamic response of elastic blades on elastic shafting, the mechanical simulation of various dynamical loadings representative of those seen in operating engines, and the measurement of engine dynamic deflections and interface forces caused by alternative engine mounting configurations and compliances.

Development of a coupled expert system for the spacecraft attitude control problem

NASA Technical Reports Server (NTRS)

Kawamura, K.; Beale, G.; Schaffer, J.; Hsieh, B.-J.; Padalkar, S.; Rodriguezmoscoso, J.; Vinz, F.; Fernandez, K.

1987-01-01

A majority of the current expert systems focus on the symbolic-oriented logic and inference mechanisms of artificial intelligence (AI). Common rule-based systems employ empirical associations and are not well suited to deal with problems often arising in engineering. Described is a prototype expert system which combines both symbolic and numeric computing. The expert system's configuration is presented and its application to a spacecraft attitude control problem is discussed.

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.

Harnessing biomechanics to develop cartilage regeneration strategies.

PubMed

Athanasiou, Kyriacos A; Responte, Donald J; Brown, Wendy E; Hu, Jerry C

2015-02-01

As this review was prepared specifically for the American Society of Mechanical Engineers H.R. Lissner Medal, it primarily discusses work toward cartilage regeneration performed in Dr. Kyriacos A. Athanasiou's laboratory over the past 25 years. The prevalence and severity of degeneration of articular cartilage, a tissue whose main function is largely biomechanical, have motivated the development of cartilage tissue engineering approaches informed by biomechanics. This article provides a review of important steps toward regeneration of articular cartilage with suitable biomechanical properties. As a first step, biomechanical and biochemical characterization studies at the tissue level were used to provide design criteria for engineering neotissues. Extending this work to the single cell and subcellular levels has helped to develop biochemical and mechanical stimuli for tissue engineering studies. This strong mechanobiological foundation guided studies on regenerating hyaline articular cartilage, the knee meniscus, and temporomandibular joint (TMJ) fibrocartilage. Initial tissue engineering efforts centered on developing biodegradable scaffolds for cartilage regeneration. After many years of studying scaffold-based cartilage engineering, scaffoldless approaches were developed to address deficiencies of scaffold-based systems, resulting in the self-assembling process. This process was further improved by employing exogenous stimuli, such as hydrostatic pressure, growth factors, and matrix-modifying and catabolic agents, both singly and in synergistic combination to enhance neocartilage functional properties. Due to the high cell needs for tissue engineering and the limited supply of native articular chondrocytes, costochondral cells are emerging as a suitable cell source. Looking forward, additional cell sources are investigated to render these technologies more translatable. For example, dermis isolated adult stem (DIAS) cells show potential as a source of chondrogenic cells. The challenging problem of enhanced integration of engineered cartilage with native cartilage is approached with both familiar and novel methods, such as lysyl oxidase (LOX). These diverse tissue engineering strategies all aim to build upon thorough biomechanical characterizations to produce functional neotissue that ultimately will help combat the pressing problem of cartilage degeneration. As our prior research is reviewed, we look to establish new pathways to comprehensively and effectively address the complex problems of musculoskeletal cartilage regeneration.

Surface Analysis and Tools

NASA Technical Reports Server (NTRS)

Miyoshi, Kazuhisa

2002-01-01

This article is a chapter of the book entitled, "Tribology of Mechanical Systems," to be published by ASME Press, New York, NY. It describes selected analytical techniques, which are being used in understanding phenomena and mechanisms of oxidation, adhesion, bonding, friction, erosion, abrasion, and wear, and in defining the problems. The primary emphasis is on microanalytical approaches to engineering surfaces.

Using LEGO Kits to Teach Higher Level Problem Solving Skills in System Dynamics: A Case Study

ERIC Educational Resources Information Center

Wu, Yi; de Vries, Charlotte; Dunsworth, Qi

2018-01-01

System Dynamics is a required course offered to junior Mechanical Engineering students at Penn State Erie, the Behrend College. It addresses the intercoupling dynamics of a wide range of dynamic systems: including mechanical, electrical, fluid, hydraulic, electromechanical, and biomedical systems. This course is challenging for students due to the…

Performance Parameters Analysis of an XD3P Peugeot Engine Using Artificial Neural Networks (ANN) Concept in MATLAB

NASA Astrophysics Data System (ADS)

Rangaswamy, T.; Vidhyashankar, S.; Madhusudan, M.; Bharath Shekar, H. R.

2015-04-01

The current trends of engineering follow the basic rule of innovation in mechanical engineering aspects. For the engineers to be efficient, problem solving aspects need to be viewed in a multidimensional perspective. One such methodology implemented is the fusion of technologies from other disciplines in order to solve the problems. This paper mainly deals with the application of Neural Networks in order to analyze the performance parameters of an XD3P Peugeot engine (used in Ministry of Defence). The basic propaganda of the work is divided into two main working stages. In the former stage, experimentation of an IC engine is carried out in order to obtain the primary data. In the latter stage the primary database formed is used to design and implement a predictive neural network in order to analyze the output parameters variation with respect to each other. A mathematical governing equation for the neural network is obtained. The obtained polynomial equation describes the characteristic behavior of the built neural network system. Finally, a comparative study of the results is carried out.

An Introduction to the Mechanical Properties of Ceramics

NASA Astrophysics Data System (ADS)

Green, David J.

1998-09-01

Over the past twenty-five years ceramics have become key materials in the development of many new technologies as scientists have been able to design these materials with new structures and properties. An understanding of the factors that influence their mechanical behavior and reliability is essential. This book will introduce the reader to current concepts in the field. It contains problems and exercises to help readers develop their skills. This is a comprehensive introduction to the mechanical properties of ceramics, and is designed primarily as a textbook for advanced undergraduates in materials science and engineering. It will also be of value as a supplementary text for more general courses and to industrial scientists and engineers involved in the development of ceramic-based products, materials selection and mechanical design.

Making objective decisions in mechanical engineering problems

NASA Astrophysics Data System (ADS)

Raicu, A.; Oanta, E.; Sabau, A.

2017-08-01

Decision making process has a great influence in the development of a given project, the goal being to select an optimal choice in a given context. Because of its great importance, the decision making was studied using various science methods, finally being conceived the game theory that is considered the background for the science of logical decision making in various fields. The paper presents some basic ideas regarding the game theory in order to offer the necessary information to understand the multiple-criteria decision making (MCDM) problems in engineering. The solution is to transform the multiple-criteria problem in a one-criterion decision problem, using the notion of utility, together with the weighting sum model or the weighting product model. The weighted importance of the criteria is computed using the so-called Step method applied to a relation of preferences between the criteria. Two relevant examples from engineering are also presented. The future directions of research consist of the use of other types of criteria, the development of computer based instruments for decision making general problems and to conceive a software module based on expert system principles to be included in the Wiki software applications for polymeric materials that are already operational.

A review on recent contribution of meshfree methods to structure and fracture mechanics applications.

PubMed

Daxini, S D; Prajapati, J M

2014-01-01

Meshfree methods are viewed as next generation computational techniques. With evident limitations of conventional grid based methods, like FEM, in dealing with problems of fracture mechanics, large deformation, and simulation of manufacturing processes, meshfree methods have gained much attention by researchers. A number of meshfree methods have been proposed till now for analyzing complex problems in various fields of engineering. Present work attempts to review recent developments and some earlier applications of well-known meshfree methods like EFG and MLPG to various types of structure mechanics and fracture mechanics applications like bending, buckling, free vibration analysis, sensitivity analysis and topology optimization, single and mixed mode crack problems, fatigue crack growth, and dynamic crack analysis and some typical applications like vibration of cracked structures, thermoelastic crack problems, and failure transition in impact problems. Due to complex nature of meshfree shape functions and evaluation of integrals in domain, meshless methods are computationally expensive as compared to conventional mesh based methods. Some improved versions of original meshfree methods and other techniques suggested by researchers to improve computational efficiency of meshfree methods are also reviewed here.

Molten salt corrosion of SiC and Si3N4

NASA Technical Reports Server (NTRS)

Jacobson, N. S.; Smialek, J. L.; Fox, D. S.

1986-01-01

The most severe type of corrosion encountered in heat engines is corrosion by molten sodium sulfate, formed by the reaction of ingested sodium chloride and sulfur impurities in the fuel. This problem was studied extensively for superalloys, but only recently examined for ceramics. This problem is addressed with laboratory studies to understand the fundamental reaction mechanisms and with burner studies to provide a more realistic simulation of the conditions encountered in a heat engine. In addition the effect of corrosion on the strengths of these materials was assessed. Each of these aspects will be reviewed and some ideas toward possible solutions will be discussed.

Operational Problems Associated with Head-Up Displays during Instrument Flight.

DTIC Science & Technology

1980-10-01

Force project engineers were Major Michael F. Rundle and Mr. William L. Welde . 41 4 TABLE OF CONTENTS Page ABBREVIATIONS...of Automotive Engineers SETP Society of Experimental Test Pilots SI Solid Instruments SNPL Syndicat National des Pilotes des Lignes (French ALPA) TACAN...Factors Relevent to Jet Upsets ," Lessons with Emphasis on Flight Mechanics from Operating Experience, Incidents, and Accidents, AGARD CP-76, 1971 153 J

Special Section Dedicated to ICOVP-2013: Part 2

NASA Astrophysics Data System (ADS)

Dimitrovová, Zuzana; Gonçalves, Rodrigo

2015-03-01

This section contains the second set of selected papers from the 11th edition of the biennial International Conference series on Vibration Problems (ICOVP-2013), which was held at the Instituto Superior Técnico in Lisbon, Portugal, on 9-12 September 2013, and was jointly organized by the Civil Engineering Department of the Universidade Nova de Lisboa and the Institute of Mechanical Engineering at the Instituto Superior Técnico.

Advanced Methods for Aircraft Engine Thrust and Noise Benefits: Nozzle-Inlet Flow Analysis

NASA Technical Reports Server (NTRS)

Morgan, Morris H., III; Gilinsky, Mikhail M.

2004-01-01

In this project on the first stage (2000-Ol), we continued to develop the previous joint research between the Fluid Mechanics and Acoustics Laboratory (FM&AL) at Hampton University (HU) and the Jet Noise Team (JNT) at the NASA Langley Research Center (NASA LaRC). At the second stage (2001-03), FM&AL team concentrated its efforts on solving of problems of interest to Glenn Research Center (NASA GRC), especially in the field of propulsion system enhancement. The NASA GRC R&D Directorate and LaRC Hyper-X Program specialists in a hypersonic technology jointly with the FM&AL staff conducted research on a wide region of problems in the propulsion field as well as in experimental testing and theoretical and numerical simulation analyses for advanced aircraft and rocket engines. The last year the Hampton University School of Engineering & Technology was awarded the NASA grant, for creation of the Aeropropulsion Center, and the FM&AL is a key team of the project fulfillment responsible for research in Aeropropulsion and Acoustics (Pillar I). This work is supported by joint research between the NASA GRC/ FM&AL and the Institute of Mechanics at Moscow State University (IMMSU) in Russia under a CRDF grant. The main areas of current scientific interest of the FM&AL include an investigation of the proposed and patented advanced methods for aircraft engine thrust and noise benefits. This is the main subject of our other projects, of which one is presented. The last year we concentrated our efforts to analyze three main problems: (a) new effective methods fuel injection into the flow stream in air-breathing engines; (b) new re-circulation method for mixing, heat transfer and combustion enhancement in propulsion systems and domestic industry application; (c) covexity flow The research is focused on a wide regime of problems in the propulsion field as well as in experimental testing and theoretical and numerical simulation analyses for advanced aircraft and rocket engines (see, for example, Figures 4). The FM&AL Team uses analytical methods, numerical simulations and experimental tests at the Hampton University campus, NASA and IM/MSU.

Computational performance of Free Mesh Method applied to continuum mechanics problems

PubMed Central

YAGAWA, Genki

2011-01-01

The free mesh method (FMM) is a kind of the meshless methods intended for particle-like finite element analysis of problems that are difficult to handle using global mesh generation, or a node-based finite element method that employs a local mesh generation technique and a node-by-node algorithm. The aim of the present paper is to review some unique numerical solutions of fluid and solid mechanics by employing FMM as well as the Enriched Free Mesh Method (EFMM), which is a new version of FMM, including compressible flow and sounding mechanism in air-reed instruments as applications to fluid mechanics, and automatic remeshing for slow crack growth, dynamic behavior of solid as well as large-scale Eigen-frequency of engine block as applications to solid mechanics. PMID:21558753

Forklift Truck, 4000-Pound-Capacity, Gasoline-Engine-Driven, Solid-Rubber-Tired, Allis-Chalmers Model ACC 45 NSN 3930-01-075-4937 -- Army User Survey,

DTIC Science & Technology

1982-03-01

to establish more realistic RAM data. 6. Action Taken. a. The undersigned contacted manufacturers regarding problems with the master link on the lift...Carburetor is updraft type and engine is equipped with a mechanical governor LP gas engine also avail able with same specifcations as above TRANSMISSIONS...torque by the converter Two oil-bathed, double-faced direction selec. tor clutches fully-enclosed gear-type pump. heat exchanger in bottom of radiator. 15

Biomimetics: determining engineering opportunities from nature

NASA Astrophysics Data System (ADS)

Fish, Frank E.

2009-08-01

The biomimetic approach seeks to incorporate designs based on biological organisms into engineered technologies. Biomimetics can be used to engineer machines that emulate the performance of organisms, particularly in instances where the organism's performance exceeds current mechanical technology or provides new directions to solve existing problems. For biologists, an adaptationist program has allowed for the identification of novel features of organisms based on engineering principles; whereas for engineers, identification of such novel features is necessary to exploit them for biomimetic development. Adaptations (leading edge tubercles to passively modify flow and high efficiency oscillatory propulsive systems) from marine animals demonstrate potential utility in the development of biomimetic products. Nature retains a store of untouched knowledge, which would be beneficial in advancing technology.

Elevated temperature crack growth

NASA Technical Reports Server (NTRS)

Malik, S. N.; Vanstone, R. H.; Kim, K. S.; Laflen, J. H.

1987-01-01

The objective of the Elevated Temperature Crack Growth Program is to evaluate proposed nonlinear fracture mechanics methods for application to hot section components of aircraft gas turbine engines. Progress during the past year included linear-elastic fracture mechanics data reduction on nonlinear crack growth rate data on Alloy 718. The bulk of the analytical work centered on thermal gradient problems and proposed fracture mechanics parameters. Good correlation of thermal gradient experimental displacement data and finite element prediction was obtained.

The use of physical and virtual manipulatives in an undergraduate mechanical engineering (Dynamics) course

NASA Astrophysics Data System (ADS)

Pan, Edward A.

Science, technology, engineering, and mathematics (STEM) education is a national focus. Engineering education, as part of STEM education, needs to adapt to meet the needs of the nation in a rapidly changing world. Using computer-based visualization tools and corresponding 3D printed physical objects may help nontraditional students succeed in engineering classes. This dissertation investigated how adding physical or virtual learning objects (called manipulatives) to courses that require mental visualization of mechanical systems can aid student performance. Dynamics is one such course, and tends to be taught using lecture and textbooks with static diagrams of moving systems. Students often fail to solve the problems correctly and an inability to mentally visualize the system can contribute to student difficulties. This study found no differences between treatment groups on quantitative measures of spatial ability and conceptual knowledge. There were differences between treatments on measures of mechanical reasoning ability, in favor of the use of physical and virtual manipulatives over static diagrams alone. There were no major differences in student performance between the use of physical and virtual manipulatives. Students used the physical and virtual manipulatives to test their theories about how the machines worked, however their actual time handling the manipulatives was extremely limited relative to the amount of time they spent working on the problems. Students used the physical and virtual manipulatives as visual aids when communicating about the problem with their partners, and this behavior was also seen with Traditional group students who had to use the static diagrams and gesture instead. The explanations students gave for how the machines worked provided evidence of mental simulation; however, their causal chain analyses were often flawed, probably due to attempts to decrease cognitive load. Student opinions about the static diagrams and dynamic models varied by type of model (static, physical, virtual), but were generally favorable. The Traditional group students, however, indicated that the lack of adequate representation of motion in the static diagrams was a problem, and wished they had access to the physical and virtual models.

A constitutive law for finite element contact problems with unclassical friction

NASA Technical Reports Server (NTRS)

Plesha, M. E.; Steinetz, B. M.

1986-01-01

Techniques for modeling complex, unclassical contact-friction problems arising in solid and structural mechanics are discussed. A constitutive modeling concept is employed whereby analytic relations between increments of contact surface stress (i.e., traction) and contact surface deformation (i.e., relative displacement) are developed. Because of the incremental form of these relations, they are valid for arbitrary load-deformation histories. The motivation for the development of such a constitutive law is that more realistic friction idealizations can be implemented in finite element analysis software in a consistent, straightforward manner. Of particular interest is modeling of two-body (i.e., unlubricated) metal-metal, ceramic-ceramic, and metal-ceramic contact. Interfaces involving ceramics are of engineering importance and are being considered for advanced turbine engines in which higher temperature materials offer potential for higher engine fuel efficiency.

Some problems in mechanics of growing solids with applications to AM technologies

NASA Astrophysics Data System (ADS)

Manzhirov, A. V.

2018-04-01

Additive Manufacturing (AM) technologies are an exciting area of the modern industrial revolution and have applications in engineering, medicine, electronics, aerospace industry, etc. AM enables cost-effective production of customized geometry and parts by direct fabrication from 3D data and mathematical models. Despite much progress in AM technologies, problems of mechanical analysis for AM fabricated parts yet remain to be solved. This paper deals with three main mechanical problems: the onset of residual stresses, which occur in the AM process and can lead to failure of the parts, the distortion of the final shape of AM fabricated parts, and the development of technological solutions aimed at improving existing AM technologies and creating new ones. An approach proposed deals with the construction of adequate analytical model and effective methods for the simulation of AM processes for fabricated solid parts.

Facility Reliability and Maintainability: An Investigation of the Air Force Civil Engineering Recurring Work Program

DTIC Science & Technology

1989-09-01

18:2). A recent survey by the Strategic Air Command (SAC) Mechanical Fquipment Management Evaluation Team ( MEMET ) determined that equipment was...identified by MEMET included Maintenance Action Sheets (MAS) that reported work which was not completed, and other MAS which annotated recurring work...readily apparent. Problem Military. The Deputy Chief of Staff for Engineering and Services, HQ SAC, established the MEMET in 1984 in response to a

Construction of optimum controls and trajectories of motion of the center of masses of a spacecraft equipped with the solar sail and low-thrust engine, using quaternions and Kustaanheimo-Stiefel variables

NASA Astrophysics Data System (ADS)

Sapunkov, Ya. G.; Chelnokov, Yu. N.

2014-11-01

The problem of optimum rendezvous of a controllable spacecraft (SC) with an uncontrollable spacecraft, moving over a Keplerian elliptic orbit in the gravitational field of the Sun, is considered. Control of the SC is performed using a solar sail and low-thrust engine. For solving the problem, the regular quaternion equations of the two-body problem with the Kustaanheimo-Stiefel variables and the Pontryagin maximum principle are used. The combined integral quality functional, which characterizes energy consumption for controllable SC transition from an initial to final state and the time spent for this transition, is used as a minimized functional. The differential boundary-value optimization problems are formulated, and their first integrals are found. Examples of numerical solution of problems are presented. The paper develops the application [1-6] of quaternion regular equations with the Kustaanheimo-Stiefel variables in the space flight mechanics.

Transport Phenomena.

ERIC Educational Resources Information Center

McCready, Mark J.; Leighton, David T.

1987-01-01

Discusses the problems created in graduate chemical engineering programs when students enter with a wide diversity of understandings of transport phenomena. Describes a two-semester graduate transport course sequence at the University of Notre Dame which focuses on fluid mechanics and heat and mass transfer. (TW)

A probabilistic approach to randomness in geometric configuration of scalable origami structures

NASA Astrophysics Data System (ADS)

Liu, Ke; Paulino, Glaucio; Gardoni, Paolo

2015-03-01

Origami, an ancient paper folding art, has inspired many solutions to modern engineering challenges. The demand for actual engineering applications motivates further investigation in this field. Although rooted from the historic art form, many applications of origami are based on newly designed origami patterns to match the specific requirenments of an engineering problem. The application of origami to structural design problems ranges from micro-structure of materials to large scale deployable shells. For instance, some origami-inspired designs have unique properties such as negative Poisson ratio and flat foldability. However, origami structures are typically constrained by strict mathematical geometric relationships, which in reality, can be easily violated, due to, for example, random imperfections introduced during manufacturing, or non-uniform deformations under working conditions (e.g. due to non-uniform thermal effects). Therefore, the effects of uncertainties in origami-like structures need to be studied in further detail in order to provide a practical guide for scalable origami-inspired engineering designs. Through reliability and probabilistic analysis, we investigate the effect of randomness in origami structures on their mechanical properties. Dislocations of vertices of an origami structure have different impacts on different mechanical properties, and different origami designs could have different sensitivities to imperfections. Thus we aim to provide a preliminary understanding of the structural behavior of some common scalable origami structures subject to randomness in their geometric configurations in order to help transition the technology toward practical applications of origami engineering.

NASA Space Mechanisms Handbook and Reference Guide Expanded Into CD-ROM Set

NASA Technical Reports Server (NTRS)

Fusaro, Robert L.

2002-01-01

Several NASA missions suffered failures and anomalies due to problems in applying space mechanisms technology to specific projects. Research shows that engineers often lack either adequate knowledge of mechanism design or sufficient understanding of how mechanisms affect sensitive systems. The Space Mechanisms Project conducted a Lessons Learned study and published a Space Mechanisms Handbook to help space industry engineers avoid recurring design, qualification, and application problems. The Space Mechanisms Handbook written at the NASA Glenn Research Center details the state-of-the-art in space mechanisms design as of 1998. NASA's objective in developing this Space Mechanisms Handbook was to provide readily accessible information on such areas as space mechanisms design, mechanical component availability and use, testing and qualification of mechanical systems, and a listing of worldwide space mechanisms experts and testing facilities in the United States. This handbook has been expanded into a two-volume CD-ROM set in an Adobe Acrobat format. In addition to the handbook, the CD's include (1) the two volume Space Mechanisms Lessons Learned Study, (2) proceedings from all the NASA hosted Aerospace Mechanisms Symposia held through the year 2000, (3) the Space Materials Handbook, (4) the Lubrication Handbook for the Space Industry, (5) the Structural & Mechanical Systems Long-Life Assurance Design Guidelines, (6) the Space Environments and Effects Source-Book, (7) the Spacecraft Deployable Appendages manual, (8) the Fastener Design Manual, (9) A Manual for Pyrotechnic Design, Development and Qualification, (10) the Report on Alternative Devices to Pyrotechnics on Spacecraft, and (11) Gearing (a manual). In addition, numerous other papers on tribology and lubrication are included.This technical summary of the project provides information on how to obtain the handbook and related information.

Research on EHN additive on the diesel engine combustion characteristics in plateau environment

NASA Astrophysics Data System (ADS)

Sun, Zhixin; Li, Ruoting; Wang, Xiancheng; Hu, Chuan

2017-03-01

Aiming at the combustion deterioration problem of diesel engine in plateau environment, a bench test was carried out for the effects of EHN additive on combustion characteristics of the diesel engine with intake pressure of 0.68 kPa. Test results showed that with the full load working condition of 1 400 r/min: Cylinder pressure and pressure uprising rate decreased with EHN additive added in, mechanical load on the engine could be relieved; peak value of the heat release rate decreased and its occurrence advanced, ignition delay and combustion duration were shortened; cylinder temperature and exhaust gas temperature declined, thermal load on the engine could be relieved, output torque increased while specific oil consumption decreased, and effective thermal efficiency of diesel engine increased.

Institutional profile: the London Centre for Nanotechnology.

PubMed

Weston, David; Bontoux, Thierry

2009-12-01

Located in the London neighborhoods of Bloomsbury and South Kensington, the London Centre for Nanotechnology is a UK-based multidisciplinary research center that operates at the forefront of science and technology. It is a joint venture between two of the world's leading institutions, UCL and Imperial College London, uniting their strong capabilities in the disciplines that underpin nanotechnology: engineering, the physical sciences and biomedicine. The London Centre for Nanotechnology has a unique operating model that accesses and focuses the combined skills of the Departments of Chemistry, Physics, Materials, Medicine, Electrical and Electronic Engineering, Mechanical Engineering, Chemical Engineering, Biochemical Engineering and Earth Sciences across the two universities. It aims to provide the nanoscience and nanotechnology required to solve major problems in healthcare, information processing, energy and the environment.

More than just a game: the role of simulation in the teaching of product design and entrepreneurship to mechanical engineering students

NASA Astrophysics Data System (ADS)

Costello, Gabriel J.

2017-11-01

The purpose of this work is to contribute to the debate on the best pedagogical approach to developing undergraduate mechanical engineering skills to meet the requirements of contemporary complex working environments. The paper provides an example of using student-entrepreneur collaboration in the teaching of modules to Mechanical Engineering final-year students. Problem-based learning (PBL) is one of the most significant recent innovations in the area of education for the professions. This work proposes to make an original contribution by simulating a real-life entrepreneur interaction for the students. The current literature largely confines simulation-based learning to computer applications such as games. However, this paper argues that role playing by students interfacing with technology start-ups can also be regarded as 'simulation' in a wider sense. Consequently, the paper proposes the concept of simulation-action learning as an enhancement of PBL and to distinguish it from computer simulation.

The Effects of Student Narration in College Engineering Classes

DTIC Science & Technology

2015-01-01

93(3), 223-231. 2004. 6. Norman, G., and Schmidt, H., “Effectiveness of Problem-Based Learning Curricula: Theory, Practice and Paper Darts ...conference papers . Dr. Richard Buckley is Lt Col in the U.S. Air Force and an Assistant Professor and Senior Military Faculty at the US Air Force...journal and conference papers . Dr. Dan Jensen is a Professor of Engineering Mechanics at the U.S. Air Force Academy where he has been since 1997. He

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.

Structural Mechanics and Dynamics Branch

NASA Technical Reports Server (NTRS)

Stefko, George

2003-01-01

The 2002 annual report of the Structural Mechanics and Dynamics Branch reflects the majority of the work performed by the branch staff during the 2002 calendar year. Its purpose is to give a brief review of the branch s technical accomplishments. The Structural Mechanics and Dynamics Branch develops innovative computational tools, benchmark experimental data, and solutions to long-term barrier problems in the areas of propulsion aeroelasticity, active and passive damping, engine vibration control, rotor dynamics, magnetic suspension, structural mechanics, probabilistics, smart structures, engine system dynamics, and engine containment. Furthermore, the branch is developing a compact, nonpolluting, bearingless electric machine with electric power supplied by fuel cells for future "more electric" aircraft. An ultra-high-power-density machine that can generate projected power densities of 50 hp/lb or more, in comparison to conventional electric machines, which generate usually 0.2 hp/lb, is under development for application to electric drives for propulsive fans or propellers. In the future, propulsion and power systems will need to be lighter, to operate at higher temperatures, and to be more reliable in order to achieve higher performance and economic viability. The Structural Mechanics and Dynamics Branch is working to achieve these complex, challenging goals.

Signal Analysis of Automotive Engine Spark Ignition System using Case-Based Reasoning (CBR) and Case-based Maintenance (CBM)

NASA Astrophysics Data System (ADS)

Huang, H.; Vong, C. M.; Wong, P. K.

2010-05-01

With the development of modern technology, modern vehicles adopt electronic control system for injection and ignition. In traditional way, whenever there is any malfunctioning in an automotive engine, an automotive mechanic usually performs a diagnosis in the ignition system of the engine to check any exceptional symptoms. In this paper, we present a case-based reasoning (CBR) approach to help solve human diagnosis problem. Nevertheless, one drawback of CBR system is that the case library will be expanded gradually after repeatedly running the system, which may cause inaccuracy and longer time for the CBR retrieval. To tackle this problem, case-based maintenance (CBM) framework is employed so that the case library of the CBR system will be compressed by clustering to produce a set of representative cases. As a result, the performance (in retrieval accuracy and time) of the whole CBR system can be improved.

A new design for electrospinner collecting device facilitates the removal of small diameter tubular scaffolds and paves the way for tissue engineering of capillaries.

PubMed

Sohrabi, Abbas; Naderi, Mahmood; Gorjipour, Fazel; Ghamgosar, Abolfazl; Ahmadbeigi, Naser

2016-09-10

Electrospinning is a technique widely used for tissue engineering. Despite hurdles, electrospun vascular tissue scaffolds has shown great promise in in vitro studies. One problem is the removal of tubular scaffolds from a electrospinning collection device with no unwanted crumpling or tearing, especially for small diameter scaffolds. To tackle this problem we designed a collection device for simple removal of the scaffold from the collector while no chemical pretreatment was required. The scaffolds fabricated on this collecting device maintained their tubular structure and showed favorable surface properties, mechanical strength and biocompatibility. The device offers a new opportunity for tissue engineering researchers to fabricate tubular scaffolds from materials which have not been possible to date and help them improve the quality of synthesized scaffolds. Copyright © 2016 Elsevier Inc. All rights reserved.

Internationalizing professional codes in engineering.

PubMed

Harris, Charles E

2004-07-01

Professional engineering societies which are based in the United States, such as the American Society of Mechanical Engineers (ASME, now ASME International) are recognizing that their codes of ethics must apply to engineers working throughout the world. An examination of the ethical code of the ASME International shows that its provisions pose many problems of application, especially in societies outside the United States. In applying the codes effectively in the international environment, two principal issues must be addressed. First, some Culture Transcending Guidelines must be identified and justified. Nine such guidelines are identified Second, some methods for applying the codes to particular situations must be identified Three such methods are specification, balancing, and finding a creative middle way.

Ethical aspects of the mitigation obstruction argument against climate engineering research.

PubMed

Morrow, David R

2014-12-28

Many commentators fear that climate engineering research might lead policy-makers to reduce mitigation efforts. Most of the literature on this so-called 'moral hazard' problem focuses on the prediction that climate engineering research would reduce mitigation efforts. This paper focuses on a related ethical question: Why would it be a bad thing if climate engineering research obstructed mitigation? If climate engineering promises to be effective enough, it might justify some reduction in mitigation. Climate policy portfolios involving sufficiently large or poorly planned reductions in mitigation, however, could lead to an outcome that would be worse than the portfolio that would be chosen in the absence of further climate engineering research. This paper applies three ethical perspectives to describe the kinds of portfolios that would be worse than that 'baseline portfolio'. The literature on climate engineering identifies various mechanisms that might cause policy-makers to choose these inferior portfolios, but it is difficult to know in advance whether the existence of these mechanisms means that climate engineering research really would lead to a worse outcome. In the light of that uncertainty, a precautionary approach suggests that researchers should take measures to reduce the risk of mitigation obstruction. Several such measures are suggested. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Functional tissue engineering of tendon: Establishing biological success criteria for improving tendon repair.

PubMed

Breidenbach, Andrew P; Gilday, Steven D; Lalley, Andrea L; Dyment, Nathaniel A; Gooch, Cynthia; Shearn, Jason T; Butler, David L

2014-06-27

Improving tendon repair using Functional Tissue Engineering (FTE) principles has been the focus of our laboratory over the last decade. Although our primary goals were initially focused only on mechanical outcomes, we are now carefully assessing the biological properties of our tissue-engineered tendon repairs so as to link biological influences with mechanics. However, given the complexities of tendon development and healing, it remains challenging to determine which aspects of tendon biology are the most important to focus on in the context of tissue engineering. To address this problem, we have formalized a strategy to identify, prioritize, and evaluate potential biological success criteria for tendon repair. We have defined numerous biological properties of normal tendon relative to cellular phenotype, extracellular matrix and tissue ultra-structure that we would like to reproduce in our tissue-engineered repairs and prioritized these biological criteria by examining their relative importance during both normal development and natural tendon healing. Here, we propose three specific biological criteria which we believe are essential for normal tendon function: (1) scleraxis-expressing cells; (2) well-organized and axially-aligned collagen fibrils having bimodal diameter distribution; and (3) a specialized tendon-to-bone insertion site. Moving forward, these biological success criteria will be used in conjunction with our already established mechanical success criteria to evaluate the effectiveness of our tissue-engineered tendon repairs. © 2013 Published by Elsevier Ltd.

Mechanic watches a General Electric I-40 Engine Fire

NASA Image and Video Library

1948-01-21

A mechanic watches the firing of a General Electric I-40 turbojet at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. The military selected General Electric’s West Lynn facility in 1941 to secretly replicate the centrifugal turbojet engine designed by British engineer Frank Whittle. General Electric’s first attempt, the I-A, was fraught with problems. The design was improved somewhat with the subsequent I-16 engine. It was not until the engine's next reincarnation as the I-40 in 1943 that General Electric’s efforts paid off. The 4000-pound thrust I-40 was incorporated into the Lockheed Shooting Star airframe and successfully flown in June 1944. The Shooting Star became the US’s first successful jet aircraft and the first US aircraft to reach 500 miles per hour. NACA Lewis studied all of General Electric’s centrifugal turbojet models during the 1940s. In 1945 the entire Shooting Star aircraft was investigated in the Altitude Wind Tunnel. Engine compressor performance and augmentation by water injection; comparison of different fuel blends in a single combustor; and air-cooled rotors were studied. The mechanic in this photograph watches the firing of a full-scale I-40 in the Jet Propulsion Static Laboratory. The facility was quickly built in 1943 specifically in order to test the early General Electric turbojets. The I-A was secretly analyzed in the facility during the fall of 1943.

The materials used in bone tissue engineering

NASA Astrophysics Data System (ADS)

Tereshchenko, V. P.; Kirilova, I. A.; Sadovoy, M. A.; Larionov, P. M.

2015-11-01

Bone tissue engineering looking for an alternative solution to the problem of skeletal injuries. The method is based on the creation of tissue engineered bone tissue equivalent with stem cells, osteogenic factors, and scaffolds - the carriers of these cells. For production of tissue engineered bone equivalent is advisable to create scaffolds similar in composition to natural extracellular matrix of the bone. This will provide optimal conditions for the cells, and produce favorable physico-mechanical properties of the final construction. This review article gives an analysis of the most promising materials for the manufacture of cell scaffolds. Biodegradable synthetic polymers are the basis for the scaffold, but it alone cannot provide adequate physical and mechanical properties of the construction, and favorable conditions for the cells. Addition of natural polymers improves the strength characteristics and bioactivity of constructions. Of the inorganic compounds, to create cell scaffolds the most widely used calcium phosphates, which give the structure adequate stiffness and significantly increase its osteoinductive capacity. Signaling molecules do not affect the physico-mechanical properties of the scaffold, but beneficial effect is on the processes of adhesion, proliferation and differentiation of cells. Biodegradation of the materials will help to fulfill the main task of bone tissue engineering - the ability to replace synthetic construct by natural tissues that will restore the original anatomical integrity of the bone.

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.

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).

Effect of oxidation products on service properties of motor oils

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

Zhitova, T.Yu.; Polipanov, I.S.

1995-01-01

One of the most urgent problems in chemmotology is how to create in an engine - lube oil system a controllable tribochemical process for the purpose of stabilizing the service properties of the oil and forming protective surface structures on the engine parts in order to minimize wear. The complexity of this problem reflects the diversity of the processes taking place in the tribological system. It is impossible to elucidate the mechanism of tribochemical reactions without studying the influence of changes in the oil composition and structure on its service properties during the course of operation. If the relationships involvedmore » in this influence are defined, it will become possible to change the structure of the oil in the desired direction and to achieve the desired service properties. For our studies we selected the motor oil M-10-G{sub 2}, conforming to GOST 8581-78. Samples of this oil were drawn during test-stand evaluations of D-144 and D-144-60 tractor diesels without any oil changes these tests were conducted jointly by the Institute of Problems in Mechanical Engineering of the Russian Academy of Sciences, the Scientific-Research and Design-Technology Institute of Tractor and Combine Engines (NIKTID), and the Vladimir Tractor Plant Production Association. Tests were run for 1000 h with the standard conditions and test sequence, and for 1500 and 2300 h under conditions of a {open_quotes}constantly acting tribochemical regime{close_quotes}. Oil samples were drawn at 50-100 h intervals and tested by standard methods to determine the following physico-chemical characteristics: kinematic viscosity, acid and base numbers, ash, carbon residue, content of insoluble sludge, and content of particulate contaminant.« less

NASA Aeronautics Multidisciplinary Analysis and Design Fellowship Program

NASA Technical Reports Server (NTRS)

Grossman, B.; Guerdal, Z.; Haftka, R. T.; Kapania, R. K.; Mason, W. H.; Mook, D. T.

1998-01-01

For a number of years, Virginia Tech had been on the forefront of research in the area of multidisciplinary analysis and design. In June of 1994, faculty members from aerospace and ocean engineering, engineering science and mechanics, mechanical engineering, industrial engineering, mathematics and computer sciences, at Virginia Tech joined together to form the Multidisciplinary Analysis and Design (MAD) Center for Advanced Vehicles. The center was established with the single goal: to perform research that is relevant to the needs of the US industry and to foster collaboration between the university, government and industry. In October of 1994, the center was chosen by NASA headquarters as one of the five university centers to establish a fellowship program to develop a graduate program in multidisciplinary analysis and design. The fellowship program provides full stipend and tuition support for seven U. S. students per year during their graduate studies. To advise us regarding the problems faced by the industry, an industrial advisory board has been formed consisting of representatives from industry as well as government laboratories. The function of the advisory board is to channel information from its member companies to faculty members concerning problems that need research attention in the general area of multidisciplinary design optimization (MDO). The faculty and their graduate students make proposals to the board on how to address these problems. At the annual board meeting in Blacksburg, the board discusses the proposals and suggests which students get funded under the NASA fellowship program. All students participating in the program are required to spend 3-6 months in industry working on their research projects. We are completing the third year of the fellowship program and have had three advisory board meetings in Blacksburg.

The use of telemetry in testing in high performance racing engines

NASA Astrophysics Data System (ADS)

Hauser, E.

Telemetry measurement data in mobile application and under difficult environmental conditions were recorded. All relevant racing car and engine parameters were measured: pressure, stress, temperature, acceleration, ignition, number of revolutions, control of electronic injection, and flow measurements on the car body. The difficult measuring conditions due to high voltage ignition, mechanical loads and vibrations impose special requirements on a telemetry system built in racing cars. It has to be compact, flexible, light, and mechanically robust and has to fulfil special sheilding conditions. The measured data are transfered to a stationary measurement car via a radio line, involving RF communication problems. The measured data are directly displayed and evaluated in the measurement car.

Improved Problem Formulation in Engineering Systems Design

DTIC Science & Technology

1990-05-01

Journal model is ASME Journal of Mechanical Design. 2 1.1 Research Objective and Methods The objective of this research project was to improve...Methods and Theories, Journal of Design Methods Group, Vol. 20, No. 2, 1986, p. 410. 19 Nadler, G., Smith, J. M. and Frey, C. E., "Problem...sources do you routinely use to gather the information you need to develop a packaging system? 26 Trade journals 6 Consultants 21 Reference books 26

Physics and nuclear power

NASA Astrophysics Data System (ADS)

Buttery, N. E.

2008-03-01

Nuclear power owes its origin to physicists. Fission was demonstrated by physicists and chemists and the first nuclear reactor project was led by physicists. However as nuclear power was harnessed to produce electricity the role of the engineer became stronger. Modern nuclear power reactors bring together the skills of physicists, chemists, chemical engineers, electrical engineers, mechanical engineers and civil engineers. The paper illustrates this by considering the Sizewell B project and the role played by physicists in this. This covers not only the roles in design and analysis but in problem solving during the commissioning of first of a kind plant. Looking forward to the challenges to provide sustainable and environmentally acceptable energy sources for the future illustrates the need for a continuing synergy between physics and engineering. This will be discussed in the context of the challenges posed by Generation IV reactors.

Protein mechanics: from single molecules to functional biomaterials.

PubMed

Li, Hongbin; Cao, Yi

2010-10-19

Elastomeric proteins act as the essential functional units in a wide variety of biomechanical machinery and serve as the basic building blocks for biological materials that exhibit superb mechanical properties. These proteins provide the desired elasticity, mechanical strength, resilience, and toughness within these materials. Understanding the mechanical properties of elastomeric protein-based biomaterials is a multiscale problem spanning from the atomistic/molecular level to the macroscopic level. Uncovering the design principles of individual elastomeric building blocks is critical both for the scientific understanding of multiscale mechanics of biomaterials and for the rational engineering of novel biomaterials with desirable mechanical properties. The development of single-molecule force spectroscopy techniques has provided methods for characterizing mechanical properties of elastomeric proteins one molecule at a time. Single-molecule atomic force microscopy (AFM) is uniquely suited to this purpose. Molecular dynamic simulations, protein engineering techniques, and single-molecule AFM study have collectively revealed tremendous insights into the molecular design of single elastomeric proteins, which can guide the design and engineering of elastomeric proteins with tailored mechanical properties. Researchers are focusing experimental efforts toward engineering artificial elastomeric proteins with mechanical properties that mimic or even surpass those of natural elastomeric proteins. In this Account, we summarize our recent experimental efforts to engineer novel artificial elastomeric proteins and develop general and rational methodologies to tune the nanomechanical properties of elastomeric proteins at the single-molecule level. We focus on general design principles used for enhancing the mechanical stability of proteins. These principles include the development of metal-chelation-based general methodology, strategies to control the unfolding hierarchy of multidomain elastomeric proteins, and the design of novel elastomeric proteins that exhibit stimuli-responsive mechanical properties. Moving forward, we are now exploring the use of these artificial elastomeric proteins as building blocks of protein-based biomaterials. Ultimately, we would like to rationally tailor mechanical properties of elastomeric protein-based materials by programming the molecular sequence, and thus nanomechanical properties, of elastomeric proteins at the single-molecule level. This step would help bridge the gap between single protein mechanics and material biomechanics, revealing how the mechanical properties of individual elastomeric proteins are translated into the properties of macroscopic materials.

Use of a Mobile Application to Help Students Develop Skills Needed in Solving Force Equilibrium Problems

NASA Astrophysics Data System (ADS)

Yang, Eunice

2016-02-01

This paper discusses the use of a free mobile engineering application (app) called Autodesk® ForceEffect™ to provide students assistance with spatial visualization of forces and more practice in solving/visualizing statics problems compared to the traditional pencil-and-paper method. ForceEffect analyzes static rigid-body systems using free-body diagrams (FBDs) and provides solutions in real time. It is a cost-free software that is available for download on the Internet. The software is supported on the iOS™, Android™, and Google Chrome™ platforms. It is easy to use and the learning curve is approximately two hours using the tutorial provided within the app. The use of ForceEffect has the ability to provide students different problem modalities (textbook, real-world, and design) to help them acquire and improve on skills that are needed to solve force equilibrium problems. Although this paper focuses on the engineering mechanics statics course, the technology discussed is also relevant to the introductory physics course.

Fleet/TYCOM Level Survey of Armament Handling Problems - Task One of the Naval Aviation Armament Support Equipment Program Management Study

DTIC Science & Technology

1977-06-21

7. AUTHOR(#) 6. CONTRACT OR GRANT NUMBER(#) PILA /UDERIAN 9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT. PROJECT, TASK...mechanically complex (i.e. contains an internal combustion engine) and/or comes in direct support of the aircraft is managed and maintained by the AIMD. The...an internal combustion engine. Accordingly, only the Aero 33D/E Trailer, Aero 51B Trailer, 21A/C Bomb Skid, and Aero 47A Weapons Loader are maintained

Lessons Learned from Crowdsourcing Complex Engineering Tasks.

PubMed

Staffelbach, Matthew; Sempolinski, Peter; Kijewski-Correa, Tracy; Thain, Douglas; Wei, Daniel; Kareem, Ahsan; Madey, Gregory

2015-01-01

Crowdsourcing is the practice of obtaining needed ideas, services, or content by requesting contributions from a large group of people. Amazon Mechanical Turk is a web marketplace for crowdsourcing microtasks, such as answering surveys and image tagging. We explored the limits of crowdsourcing by using Mechanical Turk for a more complicated task: analysis and creation of wind simulations. Our investigation examined the feasibility of using crowdsourcing for complex, highly technical tasks. This was done to determine if the benefits of crowdsourcing could be harnessed to accurately and effectively contribute to solving complex real world engineering problems. Of course, untrained crowds cannot be used as a mere substitute for trained expertise. Rather, we sought to understand how crowd workers can be used as a large pool of labor for a preliminary analysis of complex data. We compared the skill of the anonymous crowd workers from Amazon Mechanical Turk with that of civil engineering graduate students, making a first pass at analyzing wind simulation data. For the first phase, we posted analysis questions to Amazon crowd workers and to two groups of civil engineering graduate students. A second phase of our experiment instructed crowd workers and students to create simulations on our Virtual Wind Tunnel website to solve a more complex task. With a sufficiently comprehensive tutorial and compensation similar to typical crowd-sourcing wages, we were able to enlist crowd workers to effectively complete longer, more complex tasks with competence comparable to that of graduate students with more comprehensive, expert-level knowledge. Furthermore, more complex tasks require increased communication with the workers. As tasks become more complex, the employment relationship begins to become more akin to outsourcing than crowdsourcing. Through this investigation, we were able to stretch and explore the limits of crowdsourcing as a tool for solving complex problems.

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.

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.

Engineering students' experiences and perceptions of workplace problem solving

NASA Astrophysics Data System (ADS)

Pan, Rui

In this study, I interviewed 22 engineering Co-Op students about their workplace problem solving experiences and reflections and explored: 1) Of Co-Op students who experienced workplace problem solving, what are the different ways in which students experience workplace problem solving? 2) How do students perceive a) the differences between workplace problem solving and classroom problem solving and b) in what areas are they prepared by their college education to solve workplace problems? To answer my first research question, I analyzed data through the lens of phenomenography and I conducted thematic analysis to answer my second research question. The results of this study have implications for engineering education and engineering practice. Specifically, the results reveal the different ways students experience workplace problem solving, which provide engineering educators and practicing engineers a better understanding of the nature of workplace engineering. In addition, the results indicate that there is still a gap between classroom engineering and workplace engineering. For engineering educators who aspire to prepare students to be future engineers, it is imperative to design problem solving experiences that can better prepare students with workplace competency.

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.

Examining the Critical Thinking Dispositions and the Problem Solving Skills of Computer Engineering Students

ERIC Educational Resources Information Center

Özyurt, Özcan

2015-01-01

Problem solving is an indispensable part of engineering. Improving critical thinking dispositions for solving engineering problems is one of the objectives of engineering education. In this sense, knowing critical thinking and problem solving skills of engineering students is of importance for engineering education. This study aims to determine…

Lessons Learned from Crowdsourcing Complex Engineering Tasks

PubMed Central

Kijewski-Correa, Tracy; Thain, Douglas; Kareem, Ahsan; Madey, Gregory

2015-01-01

Crowdsourcing Crowdsourcing is the practice of obtaining needed ideas, services, or content by requesting contributions from a large group of people. Amazon Mechanical Turk is a web marketplace for crowdsourcing microtasks, such as answering surveys and image tagging. We explored the limits of crowdsourcing by using Mechanical Turk for a more complicated task: analysis and creation of wind simulations. Harnessing Crowdworkers for Engineering Our investigation examined the feasibility of using crowdsourcing for complex, highly technical tasks. This was done to determine if the benefits of crowdsourcing could be harnessed to accurately and effectively contribute to solving complex real world engineering problems. Of course, untrained crowds cannot be used as a mere substitute for trained expertise. Rather, we sought to understand how crowd workers can be used as a large pool of labor for a preliminary analysis of complex data. Virtual Wind Tunnel We compared the skill of the anonymous crowd workers from Amazon Mechanical Turk with that of civil engineering graduate students, making a first pass at analyzing wind simulation data. For the first phase, we posted analysis questions to Amazon crowd workers and to two groups of civil engineering graduate students. A second phase of our experiment instructed crowd workers and students to create simulations on our Virtual Wind Tunnel website to solve a more complex task. Conclusions With a sufficiently comprehensive tutorial and compensation similar to typical crowd-sourcing wages, we were able to enlist crowd workers to effectively complete longer, more complex tasks with competence comparable to that of graduate students with more comprehensive, expert-level knowledge. Furthermore, more complex tasks require increased communication with the workers. As tasks become more complex, the employment relationship begins to become more akin to outsourcing than crowdsourcing. Through this investigation, we were able to stretch and explore the limits of crowdsourcing as a tool for solving complex problems. PMID:26383029

Learning Mechanisms in Multidisciplinary Teamwork with Real Customers and Open-Ended Problems

ERIC Educational Resources Information Center

Heikkinen, Juho; Isomöttönen, Ville

2015-01-01

Recently, there has been a trend towards adding a multidisciplinary or multicultural element to traditional monodisciplinary project courses in computing and engineering. In this article, we examine the implications of multidisciplinarity for students' learning experiences during a one-semester project course for real customers. We use a…

MET Senior Projects at an Urban University.

ERIC Educational Resources Information Center

Neff, Gregory; And Others

A report describes the Purdue University Calumet Mechanical Engineering Technology (MET) program, especially the approaches used to enhance industrial involvement and take advantage of the urban setting to find real-life senior project problems. The outreach program, used by faculty to find student senior project material, is described along with…

Urban development applications project. Urban technology transfer study

NASA Technical Reports Server (NTRS)

1975-01-01

Technology transfer is defined along with reasons for attempting to transfer technology. Topics discussed include theoretical models, stages of the innovation model, communication process model, behavior of industrial organizations, problem identification, technology search and match, establishment of a market mechanism, applications engineering, commercialization, and management of technology transfer.

Spinoff from Wind Tunnel Technology

NASA Technical Reports Server (NTRS)

1985-01-01

Douglas Juanarena, a former NASA Langley instrument design engineer, found a solution to the problem of long, repetitive tunnel runs needed to measure airflow pressures. Electronically scanned pressure (ESP) replaced mechanical systems with electronic sensors. Juanarena licensed the NASA-patented technology and now manufactures ESP modules for research centers, aerospace companies, etc.

Challenges in translating vascular tissue engineering to the pediatric clinic.

PubMed

Duncan, Daniel R; Breuer, Christopher K

2011-10-14

The development of tissue-engineered vascular grafts for use in cardiovascular surgery holds great promise for improving outcomes in pediatric patients with complex congenital cardiac anomalies. Currently used synthetic grafts have a number of shortcomings in this setting but a tissue engineering approach has emerged in the past decade as a way to address these limitations. The first clinical trial of this technology showed that it is safe and effective but the primary mode of graft failure is stenosis. A variety of murine and large animal models have been developed to study and improve tissue engineering approaches with the hope of translating this technology into routine clinical use, but challenges remain. The purpose of this report is to address the clinical problem and review recent advances in vascular tissue engineering for pediatric applications. A deeper understanding of the mechanisms of neovessel formation and stenosis will enable rational design of improved tissue-engineered vascular grafts.

Tissue Engineering of Blood Vessels: Functional Requirements, Progress, and Future Challenges.

PubMed

Kumar, Vivek A; Brewster, Luke P; Caves, Jeffrey M; Chaikof, Elliot L

2011-09-01

Vascular disease results in the decreased utility and decreased availability of autologus vascular tissue for small diameter (< 6 mm) vessel replacements. While synthetic polymer alternatives to date have failed to meet the performance of autogenous conduits, tissue-engineered replacement vessels represent an ideal solution to this clinical problem. Ongoing progress requires combined approaches from biomaterials science, cell biology, and translational medicine to develop feasible solutions with the requisite mechanical support, a non-fouling surface for blood flow, and tissue regeneration. Over the past two decades interest in blood vessel tissue engineering has soared on a global scale, resulting in the first clinical implants of multiple technologies, steady progress with several other systems, and critical lessons-learned. This review will highlight the current inadequacies of autologus and synthetic grafts, the engineering requirements for implantation of tissue-engineered grafts, and the current status of tissue-engineered blood vessel research.

A reformulation of mechanics and electrodynamics.

PubMed

Pinheiro, Mario J

2017-07-01

Classical mechanics, as commonly taught in engineering and science, are confined to the conventional Newtonian theory. But classical mechanics has not really changed in substance since Newton formulation, describing simultaneous rotation and translation of objects with somewhat complicate drawbacks, risking interpretation of forces in non-inertial frames. In this work we introduce a new variational principle for out-of-equilibrium, rotating systems, obtaining a set of two first order differential equations that introduces a thermodynamic-mechanistic time into Newton's dynamical equation, and revealing the same formal symplectic structure shared by classical mechanics, fluid mechanics and thermodynamics. The results is a more consistent formulation of dynamics and electrodynamics, explaining natural phenomena as the outcome from a balance between energy and entropy, embedding translational with rotational motion into a single equation, showing centrifugal and Coriolis force as derivatives from the transport of angular momentum, and offering a natural method to handle variational problems, as shown with the brachistochrone problem. In consequence, a new force term appears, the topological torsion current, important for spacecraft dynamics. We describe a set of solved problems showing the potential of a competing technique, with significant interest to electrodynamics as well. We expect this new approach to have impact in a large class of scientific and technological problems.

PREFACE: International Conference on Vibration Problems (ICOVP-2015)

NASA Astrophysics Data System (ADS)

2015-12-01

Vibrations produced by operating machine cause deleterious effect including excessive stresses in mechanical components and reduce the machine performance. Hence, it is important to minimize the vibrations to improve the machine performance. Machines need the materials wherein vibration characteristics such as frequency and amplitude are lower. The vibration characteristics depend on strength and other elastic constants. Therefore, study of the relation between vibration characteristics and the elastic constants of the material is very much important. In the domain of seismology, the knowledge of vibrations associated with an earthquake is needed for the mitigation plans. With the increased use of strong and light weight structures especially in defence and aero-space engineering applications, wherein, precision is very important, problems of vibrations arise. The knowledge of quality (mechanical properties) of bones comes from the study of vibrations in it. This knowledge may, for exmple, help to answer bone tissue remodelling problems. Unfortunately, vibrations mostly deal with destructive areas such as manufacturing industry, seismology, and bonemechanics. These days, mathematics has become a very important tool for Non- Destructive Evaluation (NDE) in the destructive areas. A very common issue in the said domains is that the pertinent problems result in non-linear coupled differential equations which are not easily solvable. Keeping the above facts in mind, the Department of Mathematics, Kakatiya University has organized the International Conference on Vibration Problems (ICOVP-2015) from February, 18-20, 2015 in collaboration with the Department of Mechanical Engineering, Kakatiya University, and Von-Karman Society, West Bengal. This association has already succeeded in organizing the Wave Mechanics and Vibration Conference (WMVC) in the year 2010. In the Conference, new research results were presented by the experts from eight countries. There were more than 150 participants from India and abroad. The infrastructure facilities, administrative help, and financial support provided by Kakatiya University are gratefully acknowledged. The financial support received from Telangana State Council of Higher Education, University Grant Commission (UGC), National Board for Higher Mathematics (NBHM), Department of Atomic Energy (DAE), Ministry of Earth Sciences, and State Bank of Hyderabad are thankfully acknowledged. The thanks are due to all the speakers and participants who have come to this place by performing long journies and facing many inconveniences. Thanks are also due to International Scientific Committee members, reviewers, local organizing committee members, the members of organizing sub committees, supporting staff, research scholars, and the students for their help. This Conference Series is the outcome of the contributions from the conference and is broadly classified into five sections containing the papers from Solid Mechanics (SM), Fluid Mechanics (FM), Mechanical Engineering (ME), Applied Mathematics(AM), and Physics(PH). All efforts have been made to maintain the consiouness and standards that are the Hallmarks of Institute of Physics (IOP). We appreciate the efforts of Dr.B.Sandhya Rani, Dr.G.Rajitha, and Ms. Hari Priya, research scholors in the Department of Mathematics, Kakatiya University for checking the typos and pointing out the numerous errors. We also appreciate Dr.D.Rajaiah and Mr.D.Ranadheer, research scholors, in the Department for their efforts in the preparation of some LaTeX files. International Conference on Vibration Problems (ICOVP-2015).

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

NASA Astrophysics Data System (ADS)

Kamińska, Dorota; Sapiński, Tomasz; Aitken, Nicola; Rocca, Andreas Della; Barańska, Maja; Wietsma, Remco

2017-12-01

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

The materials used in bone tissue engineering

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

Tereshchenko, V. P., E-mail: tervp@ngs.ru; Kirilova, I. A.; Sadovoy, M. A.

Bone tissue engineering looking for an alternative solution to the problem of skeletal injuries. The method is based on the creation of tissue engineered bone tissue equivalent with stem cells, osteogenic factors, and scaffolds - the carriers of these cells. For production of tissue engineered bone equivalent is advisable to create scaffolds similar in composition to natural extracellular matrix of the bone. This will provide optimal conditions for the cells, and produce favorable physico-mechanical properties of the final construction. This review article gives an analysis of the most promising materials for the manufacture of cell scaffolds. Biodegradable synthetic polymers aremore » the basis for the scaffold, but it alone cannot provide adequate physical and mechanical properties of the construction, and favorable conditions for the cells. Addition of natural polymers improves the strength characteristics and bioactivity of constructions. Of the inorganic compounds, to create cell scaffolds the most widely used calcium phosphates, which give the structure adequate stiffness and significantly increase its osteoinductive capacity. Signaling molecules do not affect the physico-mechanical properties of the scaffold, but beneficial effect is on the processes of adhesion, proliferation and differentiation of cells. Biodegradation of the materials will help to fulfill the main task of bone tissue engineering - the ability to replace synthetic construct by natural tissues that will restore the original anatomical integrity of the bone.« 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".

Novel Multidisciplinary Models Assess the Capabilities of Smart Structures to Manage Vibration, Sound, and Thermal Distortion in Aeropropulsion Components

NASA Technical Reports Server (NTRS)

Saravanos, Dimitris A.

1997-01-01

The development of aeropropulsion components that incorporate "smart" composite laminates with embedded piezoelectric actuators and sensors is expected to ameliorate critical problems in advanced aircraft engines related to vibration, noise emission, and thermal stability. To facilitate the analytical needs of this effort, the NASA Lewis Research Center has developed mechanics and multidisciplinary computational models to analyze the complicated electromechanical behavior of realistic smart-structure configurations operating in combined mechanical, thermal, and acoustic environments. The models have been developed to accommodate the particular geometries, environments, and technical challenges encountered in advanced aircraft engines, yet their unique analytical features are expected to facilitate application of this new technology in a variety of commercial applications.

Expert vs. novice: Problem decomposition/recomposition in engineering design

NASA Astrophysics Data System (ADS)

Song, Ting

The purpose of this research was to investigate the differences of using problem decomposition and problem recomposition among dyads of engineering experts, dyads of engineering seniors, and dyads of engineering freshmen. Fifty participants took part in this study. Ten were engineering design experts, 20 were engineering seniors, and 20 were engineering freshmen. Participants worked in dyads to complete an engineering design challenge within an hour. The entire design process was video and audio recorded. After the design session, members participated in a group interview. This study used protocol analysis as the methodology. Video and audio data were transcribed, segmented, and coded. Two coding systems including the FBS ontology and "levels of the problem" were used in this study. A series of statistical techniques were used to analyze data. Interview data and participants' design sketches also worked as supplemental data to help answer the research questions. By analyzing the quantitative and qualitative data, it was found that students used less problem decomposition and problem recomposition than engineer experts in engineering design. This result implies that engineering education should place more importance on teaching problem decomposition and problem recomposition. Students were found to spend less cognitive effort when considering the problem as a whole and interactions between subsystems than engineer experts. In addition, students were also found to spend more cognitive effort when considering details of subsystems. These results showed that students tended to use dept-first decomposition and experts tended to use breadth-first decomposition in engineering design. The use of Function (F), Behavior (B), and Structure (S) among engineering experts, engineering seniors, and engineering freshmen was compared on three levels. Level 1 represents designers consider the problem as an integral whole, Level 2 represents designers consider interactions between subsystems, and Level 3 represents designers consider details of subsystems. The results showed that students used more S on Level 1 and 3 but they used less F on Level 1 than engineering experts. The results imply that engineering curriculum should improve the teaching of problem definition in engineering design because students need to understand the problem before solving it.

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.

Myths and realities: Defining re-engineering for a large organization

NASA Technical Reports Server (NTRS)

Yin, Sandra; Mccreary, Julia

1992-01-01

This paper describes the background and results of three studies concerning software reverse engineering, re-engineering, and reuse (R3) hosted by the Internal Revenue Service in 1991 and 1992. The situation at the Internal Revenue--aging, piecemeal computer systems and outdated technology maintained by a large staff--is familiar to many institutions, especially among management information systems. The IRS is distinctive for the sheer magnitude and diversity of its problems; the country's tax records are processed using assembly language and COBOL and spread across tape and network DBMS files. How do we proceed with replacing legacy systems? The three software re-engineering studies looked at methods, CASE tool support, and performed a prototype project using re-engineering methods and tools. During the course of these projects, we discovered critical issues broader than the mechanical definitions of methods and tool technology.

Process Improvement Through Tool Integration in Aero-Mechanical Design

NASA Technical Reports Server (NTRS)

Briggs, Clark

2010-01-01

Emerging capabilities in commercial design tools promise to significantly improve the multi-disciplinary and inter-disciplinary design and analysis coverage for aerospace mechanical engineers. This paper explores the analysis process for two example problems of a wing and flap mechanical drive system and an aircraft landing gear door panel. The examples begin with the design solid models and include various analysis disciplines such as structural stress and aerodynamic loads. Analytical methods include CFD, multi-body dynamics with flexible bodies and structural analysis. Elements of analysis data management, data visualization and collaboration are also included.

Problem Decomposition and Recomposition in Engineering Design: A Comparison of Design Behavior between Professional Engineers, Engineering Seniors, and Engineering Freshmen

ERIC Educational Resources Information Center

Song, Ting; Becker, Kurt; Gero, John; DeBerard, Scott; DeBerard, Oenardi; Reeve, Edward

2016-01-01

The authors investigated the differences in using problem decomposition and problem recomposition between dyads of engineering experts, engineering seniors, and engineering freshmen. Participants worked in dyads to complete an engineering design challenge within 1 hour. The entire design process was video and audio recorded. After the design…

Protein–Hydrogel Interactions in Tissue Engineering: Mechanisms and Applications

PubMed Central

Zustiak, Silviya P.; Wei, Yunqian

2013-01-01

Recent advances in our understanding of the sophistication of the cellular microenvironment and the dynamics of tissue remodeling during development, disease, and regeneration have increased our appreciation of the current challenges facing tissue engineering. As this appreciation advances, we are better equipped to approach problems in the biology and therapeutics of even more complex fields, such as stem cells and cancer. To aid in these studies, as well as the established areas of tissue engineering, including cardiovascular, musculoskeletal, and neural applications, biomaterials scientists have developed an extensive array of materials with specifically designed chemical, mechanical, and biological properties. Herein, we highlight an important topic within this area of biomaterials research, protein–hydrogel interactions. Due to inherent advantages of hydrated scaffolds for soft tissue engineering as well as specialized bioactivity of proteins and peptides, this field is well-posed to tackle major needs within emerging areas of tissue engineering. We provide an overview of the major modes of interactions between hydrogels and proteins (e.g., weak forces, covalent binding, affinity binding), examples of applications within growth factor delivery and three-dimensional scaffolds, and finally future directions within the area of hydrogel–protein interactions that will advance our ability to control the cell–biomaterial interface. PMID:23150926

An engineering approach to controlling indoor air quality.

PubMed

Woods, J E

1991-11-01

Evidence is accumulating that indicates air quality problems in residential and commercial buildings are nearly always associated with inadequacies in building design and methods of operation. Thus, the very systems depended on to control the indoor environment can become indirect sources of contamination if diligence is not exercised at each stage of a building's life: a) planning and design, b) construction and commissioning, c) operation, and d) demolition or renovation. In this paper, an engineering perspective is presented in which the existing building stock is characterized in terms of its environmental performance. Preliminary data indicate that 20 to 30% of the existing buildings have sufficient problems to manifest as sick-building syndrome or building-related illness, while another 10 to 20% may have undetected problems. Thus, only about 50 to 70% of the existing buildings qualify as healthy buildings. Two methods and three mechanisms of control are described to achieve "acceptable" indoor air quality: source control and exposure control. If sources cannot be removed, some level of occupant exposure will result. To control exposures with acceptable values, the primary sensory receptors of the occupants (i.e., thermal, ocular, auditory, and olfactory) cannot be excessively stimulated. The three exposure control mechanisms are conduction, radiation, and convection. To achieve acceptable occupant responses, it is often practical to integrate the mechanisms of radiation and convection in heating, ventilating, and air conditioning systems that are designed to provide acceptable thermal, acoustic, and air quality conditions within occupied spaces.(ABSTRACT TRUNCATED AT 250 WORDS)

An engineering approach to controlling indoor air quality.

PubMed Central

Woods, J E

1991-01-01

Evidence is accumulating that indicates air quality problems in residential and commercial buildings are nearly always associated with inadequacies in building design and methods of operation. Thus, the very systems depended on to control the indoor environment can become indirect sources of contamination if diligence is not exercised at each stage of a building's life: a) planning and design, b) construction and commissioning, c) operation, and d) demolition or renovation. In this paper, an engineering perspective is presented in which the existing building stock is characterized in terms of its environmental performance. Preliminary data indicate that 20 to 30% of the existing buildings have sufficient problems to manifest as sick-building syndrome or building-related illness, while another 10 to 20% may have undetected problems. Thus, only about 50 to 70% of the existing buildings qualify as healthy buildings. Two methods and three mechanisms of control are described to achieve "acceptable" indoor air quality: source control and exposure control. If sources cannot be removed, some level of occupant exposure will result. To control exposures with acceptable values, the primary sensory receptors of the occupants (i.e., thermal, ocular, auditory, and olfactory) cannot be excessively stimulated. The three exposure control mechanisms are conduction, radiation, and convection. To achieve acceptable occupant responses, it is often practical to integrate the mechanisms of radiation and convection in heating, ventilating, and air conditioning systems that are designed to provide acceptable thermal, acoustic, and air quality conditions within occupied spaces.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1821369

Orbital motion (3rd revised and enlarged edition)

NASA Astrophysics Data System (ADS)

Roy, A. E.

The fundamental principles of celestial mechanics are discussed in an introduction for students of astronomy, aerospace engineering, and geography. Chapters are devoted to the dynamic structure of the universe, coordinate and timekeeping systems, the reduction of observational data, the two-body problem, the many-body problem, general and special perturbations, and the stability and evolution of the solar system. Consideration is given to lunar theory, artificial satellites, rocket dynamics and transfer orbits, interplanetary and lunar trajectories, orbit determination and interplanetary navigation, binaries and other few-body systems, and many-body systems of stars. Diagrams, graphs, tables, and problems with solutions are provided.

Real-world educational experience through project-oriented graduate classes in collaboration with industry

NASA Astrophysics Data System (ADS)

Zurbuchen, Thomas H.

2007-04-01

There is a need for a motivated and innovative work force for the U.S. aerospace industry. The education of such engineers and scientists typically revolves around a fundamental knowledge of basic important technologies, such as the mechanics relevant to orbit-design, structures, avionics, and many others. A few years ago, the University of Michigan developed a Masters of Engineering program that provides students with skills that are not taught as part of a typical engineering curriculum. This program is focused on open problem solving, space systems, and space policy, as well as other classes that further their understanding of the connections between technologies and the nontechnical aspects of managing a space mission. The value of such an education is substantially increased through a direct connection to industry. An innovative problem-oriented approach has been developed that enables direct connections between industry and classroom teaching. The class works as a system study group and addresses problems of interest to and defined by a company with a specific application. We discuss such an application, a near-space lidar wind measurement system to enhance weather predictions, as well as the approach taken to link educational rationales.

Parameter estimation in spiking neural networks: a reverse-engineering approach.

PubMed

Rostro-Gonzalez, H; Cessac, B; Vieville, T

2012-04-01

This paper presents a reverse engineering approach for parameter estimation in spiking neural networks (SNNs). We consider the deterministic evolution of a time-discretized network with spiking neurons, where synaptic transmission has delays, modeled as a neural network of the generalized integrate and fire type. Our approach aims at by-passing the fact that the parameter estimation in SNN results in a non-deterministic polynomial-time hard problem when delays are to be considered. Here, this assumption has been reformulated as a linear programming (LP) problem in order to perform the solution in a polynomial time. Besides, the LP problem formulation makes the fact that the reverse engineering of a neural network can be performed from the observation of the spike times explicit. Furthermore, we point out how the LP adjustment mechanism is local to each neuron and has the same structure as a 'Hebbian' rule. Finally, we present a generalization of this approach to the design of input-output (I/O) transformations as a practical method to 'program' a spiking network, i.e. find a set of parameters allowing us to exactly reproduce the network output, given an input. Numerical verifications and illustrations are provided.

Some Open Issues on Rockfall Hazard Analysis in Fractured Rock Mass: Problems and Prospects

NASA Astrophysics Data System (ADS)

Ferrero, Anna Maria; Migliazza, Maria Rita; Pirulli, Marina; Umili, Gessica

2016-09-01

Risk is part of every sector of engineering design. It is a consequence of the uncertainties connected with the cognitive boundaries and with the natural variability of the relevant variables. In soil and rock engineering, in particular, uncertainties are linked to geometrical and mechanical aspects and the model used for the problem schematization. While the uncertainties due to the cognitive gaps could be filled by improving the quality of numerical codes and measuring instruments, nothing can be done to remove the randomness of natural variables, except defining their variability with stochastic approaches. Probabilistic analyses represent a useful tool to run parametric analyses and to identify the more significant aspects of a given phenomenon: They can be used for a rational quantification and mitigation of risk. The connection between the cognitive level and the probability of failure is at the base of the determination of hazard, which is often quantified through the assignment of safety factors. But these factors suffer from conceptual limits, which can be only overcome by adopting mathematical techniques with sound bases, not so used up to now (Einstein et al. in rock mechanics in civil and environmental engineering, CRC Press, London, 3-13, 2010; Brown in J Rock Mech Geotech Eng 4(3):193-204, 2012). The present paper describes the problems and the more reliable techniques used to quantify the uncertainties that characterize the large number of parameters that are involved in rock slope hazard assessment through a real case specifically related to rockfall. Limits of the existing approaches and future developments of the research are also provided.

Signal Analysis of Automotive Engine Spark Ignition System using Case-Based Reasoning (CBR) and Case-based Maintenance (CBM)

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

Huang, H.; Vong, C. M.; Wong, P. K.

2010-05-21

With the development of modern technology, modern vehicles adopt electronic control system for injection and ignition. In traditional way, whenever there is any malfunctioning in an automotive engine, an automotive mechanic usually performs a diagnosis in the ignition system of the engine to check any exceptional symptoms. In this paper, we present a case-based reasoning (CBR) approach to help solve human diagnosis problem. Nevertheless, one drawback of CBR system is that the case library will be expanded gradually after repeatedly running the system, which may cause inaccuracy and longer time for the CBR retrieval. To tackle this problem, case-based maintenancemore » (CBM) framework is employed so that the case library of the CBR system will be compressed by clustering to produce a set of representative cases. As a result, the performance (in retrieval accuracy and time) of the whole CBR system can be improved.« less

Renovation of a mechanical engineering senior design class to an industry-tied and team-oriented course

NASA Astrophysics Data System (ADS)

Liu, Yucheng

2017-11-01

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 the most important course component and critical assessment tool, from which problem-solving skills as well as employability skills of the ME students can be fully developed. Hands-on experiences in finite element analysis (FEA) modelling and simulation were also added into the renovated curriculum to promote the application of FEA on engineering design and assessment. Evaluation of the renovated course was conducted using two instruments and the results have shown that the course made the ME senior students more prepared for their future career and a win-win model was created between the industry partner and the ME programme through it. Impact of the renovated syllabus on Accreditation Board for Engineering Technology goals was discussed. Based on the current progress, a more substantial change is being planned to further improve the effectiveness and practicability of this design course. The renovated course was started to offer to the ME senior students at Mississippi State University.

On Riemann boundary value problems for null solutions of the two dimensional Helmholtz equation

NASA Astrophysics Data System (ADS)

Bory Reyes, Juan; Abreu Blaya, Ricardo; Rodríguez Dagnino, Ramón Martin; Kats, Boris Aleksandrovich

2018-01-01

The Riemann boundary value problem (RBVP to shorten notation) in the complex plane, for different classes of functions and curves, is still widely used in mathematical physics and engineering. For instance, in elasticity theory, hydro and aerodynamics, shell theory, quantum mechanics, theory of orthogonal polynomials, and so on. In this paper, we present an appropriate hyperholomorphic approach to the RBVP associated to the two dimensional Helmholtz equation in R^2 . Our analysis is based on a suitable operator calculus.

Simbody: multibody dynamics for biomedical research.

PubMed

Sherman, Michael A; Seth, Ajay; Delp, Scott L

Multibody software designed for mechanical engineering has been successfully employed in biomedical research for many years. For real time operation some biomedical researchers have also adapted game physics engines. However, these tools were built for other purposes and do not fully address the needs of biomedical researchers using them to analyze the dynamics of biological structures and make clinically meaningful recommendations. We are addressing this problem through the development of an open source, extensible, high performance toolkit including a multibody mechanics library aimed at the needs of biomedical researchers. The resulting code, Simbody, supports research in a variety of fields including neuromuscular, prosthetic, and biomolecular simulation, and related research such as biologically-inspired design and control of humanoid robots and avatars. Simbody is the dynamics engine behind OpenSim, a widely used biomechanics simulation application. This article reviews issues that arise uniquely in biomedical research, and reports on the architecture, theory, and computational methods Simbody uses to address them. By addressing these needs explicitly Simbody provides a better match to the needs of researchers than can be obtained by adaptation of mechanical engineering or gaming codes. Simbody is a community resource, free for any purpose. We encourage wide adoption and invite contributions to the code base at https://simtk.org/home/simbody.

Materials Science Laboratory

NASA Technical Reports Server (NTRS)

Jackson, Dionne

2005-01-01

The NASA Materials Science Laboratory (MSL) provides science and engineering services to NASA and Contractor customers at KSC, including those working for the Space Shuttle. International Space Station. and Launch Services Programs. These services include: (1) Independent/unbiased failure analysis (2) Support to Accident/Mishap Investigation Boards (3) Materials testing and evaluation (4) Materials and Processes (M&P) engineering consultation (5) Metrology (6) Chemical analysis (including ID of unknown materials) (7) Mechanical design and fabrication We provide unique solutions to unusual and urgent problems associated with aerospace flight hardware, ground support equipment and related facilities.

Controlled growth factor release from synthetic extracellular matrices

NASA Astrophysics Data System (ADS)

Lee, Kuen Yong; Peters, Martin C.; Anderson, Kenneth W.; Mooney, David J.

2000-12-01

Polymeric matrices can be used to grow new tissues and organs, and the delivery of growth factors from these matrices is one method to regenerate tissues. A problem with engineering tissues that exist in a mechanically dynamic environment, such as bone, muscle and blood vessels, is that most drug delivery systems have been designed to operate under static conditions. We thought that polymeric matrices, which release growth factors in response to mechanical signals, might provide a new approach to guide tissue formation in mechanically stressed environments. Critical design features for this type of system include the ability to undergo repeated deformation, and a reversible binding of the protein growth factors to polymeric matrices to allow for responses to repeated stimuli. Here we report a model delivery system that can respond to mechanical signalling and upregulate the release of a growth factor to promote blood vessel formation. This approach may find a number of applications, including regeneration and engineering of new tissues and more general drug-delivery applications.

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.

CASE: A Configurable Argumentation Support Engine

ERIC Educational Resources Information Center

Scheuer, O.; McLaren, B. M.

2013-01-01

One of the main challenges in tapping the full potential of modern educational software is to devise mechanisms to automatically analyze and adaptively support students' problem solving and learning. A number of such approaches have been developed to teach argumentation skills in domains as diverse as science, the Law, and ethics. Yet,…

Gas Dynamics Laboratory or Spheres NASA Langley

NASA Image and Video Library

1965-07-22

L65-5505 In the Gas Dynamics Laboratory, completed in 1951, researchers explored basic aerodynamic, heating and fluid-mechanical problems in the speed range from Mach 1.5 to Mach 8.0. Photograph published in Engineer in Charge: A History of the Langley Aeronautical Laboratory, 1917-1958 by James R. Hansen. Page 348.

The Art of Teaching the Art of Applying Mathematics

ERIC Educational Resources Information Center

Lighthill, M. J.

1971-01-01

This article (the 1971 Presidential Address to the Mathematical Association of U. K.) makes a plea that college teachers of mathematics should be better aware of the applications of mathematics in other subjects. As an example, the author describes the use of differential equations to solve certain vibrational problems in mechanical engineering.…

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

None, None

The Second SIAM Conference on Computational Science and Engineering was held in San Diego from February 10-12, 2003. Total conference attendance was 553. This is a 23% increase in attendance over the first conference. The focus of this conference was to draw attention to the tremendous range of major computational efforts on large problems in science and engineering, to promote the interdisciplinary culture required to meet these large-scale challenges, and to encourage the training of the next generation of computational scientists. Computational Science & Engineering (CS&E) is now widely accepted, along with theory and experiment, as a crucial third modemore » of scientific investigation and engineering design. Aerospace, automotive, biological, chemical, semiconductor, and other industrial sectors now rely on simulation for technical decision support. For federal agencies also, CS&E has become an essential support for decisions on resources, transportation, and defense. CS&E is, by nature, interdisciplinary. It grows out of physical applications and it depends on computer architecture, but at its heart are powerful numerical algorithms and sophisticated computer science techniques. From an applied mathematics perspective, much of CS&E has involved analysis, but the future surely includes optimization and design, especially in the presence of uncertainty. Another mathematical frontier is the assimilation of very large data sets through such techniques as adaptive multi-resolution, automated feature search, and low-dimensional parameterization. The themes of the 2003 conference included, but were not limited to: Advanced Discretization Methods; Computational Biology and Bioinformatics; Computational Chemistry and Chemical Engineering; Computational Earth and Atmospheric Sciences; Computational Electromagnetics; Computational Fluid Dynamics; Computational Medicine and Bioengineering; Computational Physics and Astrophysics; Computational Solid Mechanics and Materials; CS&E Education; Meshing and Adaptivity; Multiscale and Multiphysics Problems; Numerical Algorithms for CS&E; Discrete and Combinatorial Algorithms for CS&E; Inverse Problems; Optimal Design, Optimal Control, and Inverse Problems; Parallel and Distributed Computing; Problem-Solving Environments; Software and Wddleware Systems; Uncertainty Estimation and Sensitivity Analysis; and Visualization and Computer Graphics.« less

Sustainable Development and Energy Geotechnology Potential Roles for Geotechnical Engineering

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

FragaszyProgram Dire, Dr. R. J.; Santamarina, Carlos; Espinoza, N.

2011-01-01

The world is facing unprecedented challenges related to energy resources, global climate change, material use, and waste generation. Failure to address these challenges will inhibit the growth of the developing world and will negatively impact the standard of living and security of future generations in all nations. The solutions to these challenges will require multidisciplinary research across the social and physical sciences and engineering. Although perhaps not always recognized, geotechnical engineering expertise is critical to the solution of many energy and sustainability-related problems. Hence, geotechnical engineers and academicians have opportunity and responsibility to contribute to the solution of these worldwidemore » problems. Research will need to be extended to non-standard issues such as thermal properties of soils; sediment and rock response to extreme conditions and at very long time scales; coupled hydro-chemo-thermo-bio-mechanical processes; positive feedback systems; the development of discontinuities; biological modification of soil properties; spatial variability; and emergent phenomena. Clearly, the challenges facing geotechnical engineering in the future will require a much broader knowledge base than our traditional educational programs provide. The geotechnical engineering curricula, from undergraduate education through continuing professional education, must address the changing needs of a profession that will increasingly be engaged in alternative/renewable energy production; energy efficiency; sustainable design, enhanced and more efficient use of natural resources, waste management, and underground utilization.« less

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.

The role of a creative "joint assignment" project in biomedical engineering bachelor degree education.

PubMed

Jiehui Jiang; Yuting Zhang; Mi Zhou; Xiaosong Zheng; Zhuangzhi Yan

2017-07-01

Biomedical Engineering (BME) bachelor education aims to train qualified engineers who devote themselves to addressing biological and medical problems by integrating the technological, medical and biological knowledge. Design thinking and teamwork with other disciplines are necessary for biomedical engineers. In the current biomedical engineering education system of Shanghai University (SHU), however, such design thinking and teamwork through a practical project is lacking. This paper describes a creative "joint assignment" project in Shanghai University, China, which has provided BME bachelor students a two-year practical experience to work with students from multidisciplinary departments including sociology, mechanics, computer sciences, business and art, etc. To test the feasibility of this project, a twenty-month pilot project has been carried out from May 2015 to December 2016. The results showed that this pilot project obviously enhanced competitive power of BME students in Shanghai University, both in the capabilities of design thinking and teamwork.

Portable inference engine: An extended CLIPS for real-time production systems

NASA Technical Reports Server (NTRS)

Le, Thach; Homeier, Peter

1988-01-01

The present C-Language Integrated Production System (CLIPS) architecture has not been optimized to deal with the constraints of real-time production systems. Matching in CLIPS is based on the Rete Net algorithm, whose assumption of working memory stability might fail to be satisfied in a system subject to real-time dataflow. Further, the CLIPS forward-chaining control mechanism with a predefined conflict resultion strategy may not effectively focus the system's attention on situation-dependent current priorties, or appropriately address different kinds of knowledge which might appear in a given application. Portable Inference Engine (PIE) is a production system architecture based on CLIPS which attempts to create a more general tool while addressing the problems of real-time expert systems. Features of the PIE design include a modular knowledge base, a modified Rete Net algorithm, a bi-directional control strategy, and multiple user-defined conflict resolution strategies. Problems associated with real-time applications are analyzed and an explanation is given for how the PIE architecture addresses these problems.

Distortions and gender-related differences in the perception of mechanical engineering in high school students.

PubMed

Ferrando Piera, Pere Joan; Gutiérrez-Colón Plana, Mar; Paleo Cageao, Paloma; de la Flor López, Silvia; Ferrando Piera, Francesc

2013-01-01

The reason for this study was the low interest that high school students, particularly females, show for the subject of mechanical engineering (ME). We assumed that this problem was partly due to: (a) lack of understanding of the tasks involved in ME, and (b) a distorted and negative perception of the professional environment and working conditions. To assess these two assumptions, two measurement instruments (tasks and perceptions) were developed and administered in a sample of 496 high school students. A multiple-group design was used and data was analyzed by using an extended item response theory model. In general terms, the results agreed with our expectations. However, no significant gender differences were found. The implications of the results for future improvements are discussed.

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 efficiency evaluation of support vibration isolation with mechanic inertial motion converter for vibroactive process equipment

NASA Astrophysics Data System (ADS)

Buryan, Yu. A.; Babichev, D. O.; Silkov, M. V.; Shtripling, L. O.; Kalashnikov, B. A.

2017-08-01

This research refers to the problems of processing equipment protection from vibration influence. The theory issues of vibration isolation for vibroactive objects such as engines, pumps, compressors, fans, piping, etc. are considered. The design of the perspective air spring with the parallel mounted mechanical inertial motion converter is offered. The mathematical model of the suspension, allowing selecting options to reduce the factor of the force transmission to the base in a certain frequency range is obtained.

Mingus Discontinuous Multiphysics

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

Pat Notz, Dan Turner

Mingus provides hybrid coupled local/non-local mechanics analysis capabilities that extend several traditional methods to applications with inherent discontinuities. Its primary features include adaptations of solid mechanics, fluid dynamics and digital image correlation that naturally accommodate dijointed data or irregular solution fields by assimilating a variety of discretizations (such as control volume finite elements, peridynamics and meshless control point clouds). The goal of this software is to provide an analysis framework form multiphysics engineering problems with an integrated image correlation capability that can be used for experimental validation and model

The application of S-transformation and M-2DPCA in I.C. Engine fault diagnosis

NASA Astrophysics Data System (ADS)

Zhang, Shixiong; Cai, Yanping; Mu, Weijie

2017-04-01

According to the problem of parameter selection and feature extraction for vibration diagnosis of traditional internal combustion engine is discussed. The method based on S-transformation and Module Two Dimensional Principal Components Analysis (M-2DPCA) is proposed to carry out fault diagnosis of I.C. Engine valve mechanism. First of all, the method transfers cylinder surface vibration signals of I.C. into images through S-transform. The second, extracting the optimized projection vectors from the general distribution matrix G which is obtained by all sample sub-images, so that vibration spectrum images can be modularized using M-2DPCA. The last, these features matrix obtained from images project will served as the enters of nearest neighbor classifier, it is used to achieve fault types' division. The method is applied to the diagnosis example of the vibration signal of the valve mechanism eight operating modes, recognition rate up to 94.17 percent; the effectiveness of the proposed method is proved.

Improving Engine Efficiency Through Core Developments

NASA Technical Reports Server (NTRS)

Heidmann, James D.

2011-01-01

The NASA Environmentally Responsible Aviation (ERA) Project and Fundamental Aeronautics Projects are supporting compressor and turbine research with the goal of reducing aircraft engine fuel burn and greenhouse gas emissions. The primary goals of this work are to increase aircraft propulsion system fuel efficiency for a given mission by increasing the overall pressure ratio (OPR) of the engine while maintaining or improving aerodynamic efficiency of these components. An additional area of work involves reducing the amount of cooling air required to cool the turbine blades while increasing the turbine inlet temperature. This is complicated by the fact that the cooling air is becoming hotter due to the increases in OPR. Various methods are being investigated to achieve these goals, ranging from improved compressor three-dimensional blade designs to improved turbine cooling hole shapes and methods. Finally, a complementary effort in improving the accuracy, range, and speed of computational fluid mechanics (CFD) methods is proceeding to better capture the physical mechanisms underlying all these problems, for the purpose of improving understanding and future designs.

Examining Young Students' Problem Scoping in Engineering Design

ERIC Educational Resources Information Center

Watkins, Jessica; Spencer, Kathleen; Hammer, David

2014-01-01

Problem scoping--determining the nature and boundaries of a problem--is an essential aspect of the engineering design process. Some studies from engineering education suggest that beginning students tend to skip problem scoping or oversimplify a problem. However, the ways these studies often characterize students' problem scoping often do not…

Activist engineering: changing engineering practice by deploying praxis.

PubMed

Karwat, Darshan M A; Eagle, Walter E; Wooldridge, Margaret S; Princen, Thomas E

2015-02-01

In this paper, we reflect on current notions of engineering practice by examining some of the motives for engineered solutions to the problem of climate change. We draw on fields such as science and technology studies, the philosophy of technology, and environmental ethics to highlight how dominant notions of apoliticism and ahistoricity are ingrained in contemporary engineering practice. We argue that a solely technological response to climate change does not question the social, political, and cultural tenet of infinite material growth, one of the root causes of climate change. In response to the contemporary engineering practice, we define an activist engineer as someone who not only can provide specific engineered solutions, but who also steps back from their work and tackles the question, What is the real problem and does this problem "require" an engineering intervention? Solving complex problems like climate change requires radical cultural change, and a significant obstacle is educating engineers about how to conceive of and create "authentic alternatives," that is, solutions that differ from the paradigm of "technologically improving" our way out of problems. As a means to realize radically new solutions, we investigate how engineers might (re)deploy the concept of praxis, which raises awareness in engineers of the inherent politics of technological design. Praxis empowers engineers with a more comprehensive understanding of problems, and thus transforms technologies, when appropriate, into more socially just and ecologically sensitive interventions. Most importantly, praxis also raises a radical alternative rarely considered-not "engineering a solution." Activist engineering offers a contrasting method to contemporary engineering practice and leads toward social justice and ecological protection through problem solving by asking not, How will we technologize our way out of the problems we face? but instead, What really needs to be done?

Fracture mechanics and corrosion fatigue.

NASA Technical Reports Server (NTRS)

Mcevily, A. J.; Wei, R. P.

1972-01-01

Review of the current state-of-the-art in fracture mechanics, particularly in relation to the study of problems in environment-enhanced fatigue crack growth. The usefulness of this approach in developing understanding of the mechanisms for environmental embrittlement and its engineering utility are discussed. After a brief review of the evolution of the fracture mechanics approach and the study of environmental effects on the fatigue behavior of materials, a study is made of the response of materials to fatigue and corrosion fatigue, the modeling of the mechanisms of the fatigue process is considered, and the application of knowledge of fatigue crack growth to the prediction of the high cycle life of unnotched specimens is illustrated.

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

PubMed

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

2015-02-01

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

Liquid Sloshing Dynamics

NASA Astrophysics Data System (ADS)

Ibrahim, Raouf A.

2005-06-01

The problem of liquid sloshing in moving or stationary containers remains of great concern to aerospace, civil, and nuclear engineers; physicists; designers of road tankers and ship tankers; and mathematicians. Beginning with the fundamentals of liquid sloshing theory, this book takes the reader systematically from basic theory to advanced analytical and experimental results in a self-contained and coherent format. The book is divided into four sections. Part I deals with the theory of linear liquid sloshing dynamics; Part II addresses the nonlinear theory of liquid sloshing dynamics, Faraday waves, and sloshing impacts; Part III presents the problem of linear and nonlinear interaction of liquid sloshing dynamics with elastic containers and supported structures; and Part IV considers the fluid dynamics in spinning containers and microgravity sloshing. This book will be invaluable to researchers and graduate students in mechanical and aeronautical engineering, designers of liquid containers, and applied mathematicians.

Traffic Flow Density Distribution Based on FEM

NASA Astrophysics Data System (ADS)

Ma, Jing; Cui, Jianming

In analysis of normal traffic flow, it usually uses the static or dynamic model to numerical analyze based on fluid mechanics. However, in such handling process, the problem of massive modeling and data handling exist, and the accuracy is not high. Finite Element Method (FEM) is a production which is developed from the combination of a modern mathematics, mathematics and computer technology, and it has been widely applied in various domain such as engineering. Based on existing theory of traffic flow, ITS and the development of FEM, a simulation theory of the FEM that solves the problems existing in traffic flow is put forward. Based on this theory, using the existing Finite Element Analysis (FEA) software, the traffic flow is simulated analyzed with fluid mechanics and the dynamics. Massive data processing problem of manually modeling and numerical analysis is solved, and the authenticity of simulation is enhanced.

CSM solutions of rotating blade dynamics using integrating matrices

NASA Technical Reports Server (NTRS)

Lakin, William D.

1992-01-01

The dynamic behavior of flexible rotating beams continues to receive considerable research attention as it constitutes a fundamental problem in applied mechanics. Further, beams comprise parts of many rotating structures of engineering significance. A topic of particular interest at the present time involves the development of techniques for obtaining the behavior in both space and time of a rotor acted upon by a simple airload loading. Most current work on problems of this type use solution techniques based on normal modes. It is certainly true that normal modes cannot be disregarded, as knowledge of natural blade frequencies is always important. However, the present work has considered a computational structural mechanics (CSM) approach to rotor blade dynamics problems in which the physical properties of the rotor blade provide input for a direct numerical solution of the relevant boundary-and-initial-value problem. Analysis of the dynamics of a given rotor system may require solution of the governing equations over a long time interval corresponding to many revolutions of the loaded flexible blade. For this reason, most of the common techniques in computational mechanics, which treat the space-time behavior concurrently, cannot be applied to the rotor dynamics problem without a large expenditure of computational resources. By contrast, the integrating matrix technique of computational mechanics has the ability to consistently incorporate boundary conditions and 'remove' dependence on a space variable. For problems involving both space and time, this feature of the integrating matrix approach thus can generate a 'splitting' which forms the basis of an efficient CSM method for numerical solution of rotor dynamics problems.

Hybrid-finite-element analysis of some nonlinear and 3-dimensional problems of engineering fracture mechanics

NASA Technical Reports Server (NTRS)

Atluri, S. N.; Nakagaki, M.; Kathiresan, K.

1980-01-01

In this paper, efficient numerical methods for the analysis of crack-closure effects on fatigue-crack-growth-rates, in plane stress situations, and for the solution of stress-intensity factors for arbitrary shaped surface flaws in pressure vessels, are presented. For the former problem, an elastic-plastic finite element procedure valid for the case of finite deformation gradients is developed and crack growth is simulated by the translation of near-crack-tip elements with embedded plastic singularities. For the latter problem, an embedded-elastic-singularity hybrid finite element method, which leads to a direct evaluation of K-factors, is employed.

A parallel metaheuristic for large mixed-integer dynamic optimization problems, with applications in computational biology

PubMed Central

Henriques, David; González, Patricia; Doallo, Ramón; Saez-Rodriguez, Julio; Banga, Julio R.

2017-01-01

Background We consider a general class of global optimization problems dealing with nonlinear dynamic models. Although this class is relevant to many areas of science and engineering, here we are interested in applying this framework to the reverse engineering problem in computational systems biology, which yields very large mixed-integer dynamic optimization (MIDO) problems. In particular, we consider the framework of logic-based ordinary differential equations (ODEs). Methods We present saCeSS2, a parallel method for the solution of this class of problems. This method is based on an parallel cooperative scatter search metaheuristic, with new mechanisms of self-adaptation and specific extensions to handle large mixed-integer problems. We have paid special attention to the avoidance of convergence stagnation using adaptive cooperation strategies tailored to this class of problems. Results We illustrate its performance with a set of three very challenging case studies from the domain of dynamic modelling of cell signaling. The simpler case study considers a synthetic signaling pathway and has 84 continuous and 34 binary decision variables. A second case study considers the dynamic modeling of signaling in liver cancer using high-throughput data, and has 135 continuous and 109 binaries decision variables. The third case study is an extremely difficult problem related with breast cancer, involving 690 continuous and 138 binary decision variables. We report computational results obtained in different infrastructures, including a local cluster, a large supercomputer and a public cloud platform. Interestingly, the results show how the cooperation of individual parallel searches modifies the systemic properties of the sequential algorithm, achieving superlinear speedups compared to an individual search (e.g. speedups of 15 with 10 cores), and significantly improving (above a 60%) the performance with respect to a non-cooperative parallel scheme. The scalability of the method is also good (tests were performed using up to 300 cores). Conclusions These results demonstrate that saCeSS2 can be used to successfully reverse engineer large dynamic models of complex biological pathways. Further, these results open up new possibilities for other MIDO-based large-scale applications in the life sciences such as metabolic engineering, synthetic biology, drug scheduling. PMID:28813442

A parallel metaheuristic for large mixed-integer dynamic optimization problems, with applications in computational biology.

PubMed

Penas, David R; Henriques, David; González, Patricia; Doallo, Ramón; Saez-Rodriguez, Julio; Banga, Julio R

2017-01-01

We consider a general class of global optimization problems dealing with nonlinear dynamic models. Although this class is relevant to many areas of science and engineering, here we are interested in applying this framework to the reverse engineering problem in computational systems biology, which yields very large mixed-integer dynamic optimization (MIDO) problems. In particular, we consider the framework of logic-based ordinary differential equations (ODEs). We present saCeSS2, a parallel method for the solution of this class of problems. This method is based on an parallel cooperative scatter search metaheuristic, with new mechanisms of self-adaptation and specific extensions to handle large mixed-integer problems. We have paid special attention to the avoidance of convergence stagnation using adaptive cooperation strategies tailored to this class of problems. We illustrate its performance with a set of three very challenging case studies from the domain of dynamic modelling of cell signaling. The simpler case study considers a synthetic signaling pathway and has 84 continuous and 34 binary decision variables. A second case study considers the dynamic modeling of signaling in liver cancer using high-throughput data, and has 135 continuous and 109 binaries decision variables. The third case study is an extremely difficult problem related with breast cancer, involving 690 continuous and 138 binary decision variables. We report computational results obtained in different infrastructures, including a local cluster, a large supercomputer and a public cloud platform. Interestingly, the results show how the cooperation of individual parallel searches modifies the systemic properties of the sequential algorithm, achieving superlinear speedups compared to an individual search (e.g. speedups of 15 with 10 cores), and significantly improving (above a 60%) the performance with respect to a non-cooperative parallel scheme. The scalability of the method is also good (tests were performed using up to 300 cores). These results demonstrate that saCeSS2 can be used to successfully reverse engineer large dynamic models of complex biological pathways. Further, these results open up new possibilities for other MIDO-based large-scale applications in the life sciences such as metabolic engineering, synthetic biology, drug scheduling.

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.

An Autograding (Student) Problem Management System for the Compeuwtir Ilittur8

NASA Technical Reports Server (NTRS)

Kohne, Glenn S.

1996-01-01

In order to develop analysis skills necessary in engineering disciplines, students need practice solving problems using specified analytical techniques. Unless homework is collected and graded, students tend not to spend much time or effort in performing it. Teachers do not, realistically, have the time to grade large numbers of homework problems on a regular basis. This paper presents and makes available a miracle cure. The Autograding Problem Management System (APMS) provides a discipline-independent mechanism for teachers to create (quickly and easily) sets of homework problems. The APMS system provides CRT and/or printed summaries of the graded student responses. This presentation will demonstrate both the speed and the drag-and-drop simplicity of using the APMS to create self-grading homework problem sets comprised of traditional types of problems and of problems which would not be possible without the use of computers.

Thermo-Mechanical Behavior and Shakedown of Shape Memory Alloy Cable Structures

NASA Astrophysics Data System (ADS)

Biggs, Daniel B.

Shape memory alloys (SMAs) are a versatile class of smart materials that exhibit adaptive properties which have been applied to solve engineering problems in wide-ranging fields from aerospace to biomedical engineering. Yet there is a lack of understanding of the fundamental nature of SMAs in order to effectively apply them to challenging problems within these engineering fields. Stranding fine NiTi wires into a cable form satisfies the demands of many aerospace and civil engineering applications which require actuators to withstand large tensile loads. The impact of increased bending and twisting in stranded NiTi wire structures, as well as introducing contact mechanics to the unstable phase transformation is not well understood, and this work aims to fill that void. To study the scalability of NiTi cables, thermo-mechanical characterization tests are conducted on cables much larger than those previously tested. These cables are found to have good superelastic properties and repeatable cyclic behavior with minimal induced plasticity. The behavior of additional cables, which have higher transition temperatures that can be used in a shape memory mode as thermo-responsive, high force actuator elements, are explored. These cables are found to scale up the performance of straight wire by maintaining an equivalent work output. Moreover, this work investigates the degradation of the thermal actuation of SMA wires through novel stress-temperature paths, discovering several path dependent behaviors of transformation-induced plasticity. The local mechanics of NiTi cable structures are explored through experiments utilizing digital image correlation, revealing new periodic transformation instabilities. Finite element simulations are presented, which indicate that the instabilities are caused by friction and relative sliding between wires in a cable. Finally, a study of the convective heat transfer of helical wire involving a suite of wind tunnel experiments, numerical analyses, and an empirical correlation is presented. This provides a method to better model the thermal behavior of helical SMA actuators and highlights the non-monotonic dependence of the convective heat transfer coefficient of helical wire with respect to the angle of the flow.

Teaching Problem-Solving Skills to Nuclear Engineering Students

ERIC Educational Resources Information Center

Waller, E.; Kaye, M. H.

2012-01-01

Problem solving is an essential skill for nuclear engineering graduates entering the workforce. Training in qualitative and quantitative aspects of problem solving allows students to conceptualise and execute solutions to complex problems. Solutions to problems in high consequence fields of study such as nuclear engineering require rapid and…

Stereographic Projection Techniques for Geologists and Civil Engineers

NASA Astrophysics Data System (ADS)

Lisle, Richard J.; Leyshon, Peter R.

2004-05-01

An essential tool in the fields of structural geology and geotechnics, stereographic projection allows three-dimensional orientation data to be represented and manipulated. This revised edition presents a basic introduction to the subject with examples, illustrations and exercises that encourage the student to visualize the problems in three dimensions. It will provide students of geology, rock mechanics, and geotechnical and civil engineering with an indispensable guide to the analysis and interpretation of field orientation data. Links to useful web resources and software programs are also provided. First Edition published by Butterworth-Heinemann (1996): 0-750-62450-7

Inverse problems in quantum chemistry

NASA Astrophysics Data System (ADS)

Karwowski, Jacek

Inverse problems constitute a branch of applied mathematics with well-developed methodology and formalism. A broad family of tasks met in theoretical physics, in civil and mechanical engineering, as well as in various branches of medical and biological sciences has been formulated as specific implementations of the general theory of inverse problems. In this article, it is pointed out that a number of approaches met in quantum chemistry can (and should) be classified as inverse problems. Consequently, the methodology used in these approaches may be enriched by applying ideas and theorems developed within the general field of inverse problems. Several examples, including the RKR method for the construction of potential energy curves, determining parameter values in semiempirical methods, and finding external potentials for which the pertinent Schrödinger equation is exactly solvable, are discussed in detail.

Jet Simulation in a Diesel Engine

NASA Astrophysics Data System (ADS)

Xu, Zhiliang

2005-03-01

We present a numerical study of the jet breakup and spray formation in a diesel engine by the Front Tracking method. The mechanisms of jet breakup and spray formation of a high speed diesel jet injected through a circular nozzle are the key to design a fuel efficient, nonpolluting diesel engine. We conduct the simulations for the jet breakup within a 2D axis-symmetric geometry. Our goal is to model the spray at a micro-physical level, with the creation of individual droplets. The problem is multiscale. The droplets are a few microns in size. The nozzle is about 0.2 mm in diameter and 1 mm in length. To resolve various physical patterns such as vortex, shock waves, vacuum and track droplets and spray, the Burger-Colella adaptive mesh refinement technique is used. To simulate the spray formation, we model mixed vapor-liquid region through a heterogeneous model with dynamic vapor bubble insertion. The formation of the cavitation is represented by the dynamic creation of vapor bubbles. On the liquid/vapor interface, a phase transition problem is solved numerically. The phase transition is governed by the compressible Euler equations with heat diffusion. Our solution is a new description for the Riemann problem associated with a phase transition in a fully compressible fluid.

Influence of engine coolant composition on the electrochemical degradation behavior of EPDM radiator hoses

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

Vroomen, G.L.M.; Lievens, S.S.; Maes, J.P.

1999-08-01

EPDM (ethylene-propylene rubber) has been used for more than 25 years as the main elastomer in radiator hoses because it offers a well-balanced price/performance ratio in this field of application. Some years ago the automotive and rubber industry became aware of a problem called electrochemical degradation and cracking. Cooling systems broke down due to a typical cracking failure of some radiator hoses. Different test methods were developed to simulate and solve the problem on laboratory scale. The influence of different variables with respect to the electrochemical degradation and cracking. Cooling systems broke down due to a typical cracking failure ofmore » some radiator hoses. Different test methods were developed to simulate and solve the problem on laboratory scale. The influence of different variables with respect to the electrochemical degradation process has been investigated, but until recently the influence of the engine coolant was ignored. Using a test method developed by DSM elastomers, the influence of the composition of the engine coolant as well as of the EPDM composition has now been evaluated. This paper gives an overview of test results with different coolant technologies and offers a plausible explanation of the degradation mechanisms as a function of the elastomer composition.« less

High-performance parallel analysis of coupled problems for aircraft propulsion

NASA Technical Reports Server (NTRS)

Felippa, C. A.; Farhat, C.; Chen, P.-S.; Gumaste, U.; Leoinne, M.; Stern, P.

1995-01-01

This research program deals with the application of high-performance computing methods to the numerical simulation of complete jet engines. The program was initiated in 1993 by applying two-dimensional parallel aeroelastic codes to the interior gas flow problem of a by-pass jet engine. The fluid mesh generation, domain decomposition and solution capabilities were successfully tested. Attention was then focused on methodology for the partitioned analysis of the interaction of the gas flow with a flexible structure and with the fluid mesh motion driven by these structural displacements. The latter is treated by an ALE technique that models the fluid mesh motion as that of a fictitious mechanical network laid along the edges of near-field fluid elements. New partitioned analysis procedures to treat this coupled 3-component problem were developed in 1994. These procedures involved delayed corrections and subcycling, and have been successfully tested on several massively parallel computers. For the global steady-state axisymmetric analysis of a complete engine we have decided to use the NASA-sponsored ENG10 program, which uses a regular FV-multiblock-grid discretization in conjunction with circumferential averaging to include effects of blade forces, loss, combustor heat addition, blockage, bleeds and convective mixing. A load-balancing preprocessor for parallel versions of ENG10 has been developed. It is planned to use the steady-state global solution provided by ENG10 as input to a localized three-dimensional FSI analysis for engine regions where aeroelastic effects may be important.

Engine Development Design Margins Briefing Charts

NASA Technical Reports Server (NTRS)

Bentz, Chuck

2006-01-01

New engines experience durability problems after entering service. The most prevalent and costly is the hot section, particularly the high-pressure turbine. The origin of durability problems can be traced back to: 1) the basic aero-mechanical design systems, assumptions, and design margins used by the engine designers, 2) the available materials systems, and 3) to a large extent, aggressive marketing in a highly competitive environment that pushes engine components beyond the demonstrated capability of the basic technology available for the hardware designs. Unfortunately the user must operate the engine in the service environment in order to learn the actual thrust loading and the time at max effort take-off conditions used in service are needed to determine the hot section life. Several hundred thousand hours of operational service will be required before the demonstrated reliability of a fleet of engines or the design deficiencies of the engine hot section parts can be determined. Also, it may take three to four engine shop visits for heavy maintenance on the gas path hardware to establish cost effective build standards. Spare parts drive the oerator's engine maintenance costs but spare parts also makes lots of money for the engine manufacturer during the service life of an engine. Unless competition prevails for follow-on engine buys, there is really no motivation for an OEM to spend internal money to improve parts durability and reduce earnings derived from a lucrative spare parts business. If the hot section life is below design goals or promised values, the OEM migh argue that the engine is being operated beyond its basic design intent. On the other hand, the airframer and the operator will continue to remind the OEM that his engine was selected based on a lot of promises to deliver spec thrust with little impact on engine service life if higher thrust is used intermittently. In the end, a standoff prevails and nothing gets fixed. This briefing will propose ways to hold competing engine manufacturers more accountable for engine hot section design margins during the entire Engine Development process as well as provide tools to assess the design temperature margins in the hot section parts of Service Engines.

On a New Approach to Education about Ethics for Engineers at Meijou University

NASA Astrophysics Data System (ADS)

Fukaya, Minoru; Morimoto, Tsukasa; Kimura, Noritsugu

We propose a new approach to education of so called “engineering ethics”. This approach has two important elements in its teaching system. One is “problem-solving learning”, and the other is “discussion ability”. So far, engineering ethics started at the ethical standpoint. But we put the viewpoint of problem-solving learning at the educational base of engineering ethics. Because many problems have complicated structures, so if we want to solve them, we should discuss each other. Problem-solving ability and discussion ability, they help engineers to solve the complex problems in their social everyday life. Therefore, Meijo University names engineering ethics “ethics for engineers”. At Meijou University about 1300 students take classes in both ethics for engineers and environmental ethics for one year.

Living nano-micro fibrous woven fabric/hydrogel composite scaffolds for heart valve engineering.

PubMed

Wu, Shaohua; Duan, Bin; Qin, Xiaohong; Butcher, Jonathan T

2017-03-15

Regeneration and repair of injured or diseased heart valves remains a clinical challenge. Tissue engineering provides a promising treatment approach to facilitate living heart valve repair and regeneration. Three-dimensional (3D) biomimetic scaffolds that possess heterogeneous and anisotropic features that approximate those of native heart valve tissue are beneficial to the successful in vitro development of tissue engineered heart valves (TEHV). Here we report the development and characterization of a novel composite scaffold consisting of nano- and micro-scale fibrous woven fabrics and 3D hydrogels by using textile techniques combined with bioactive hydrogel formation. Embedded nano-micro fibrous scaffolds within hydrogel enhanced mechanical strength and physical structural anisotropy of the composite scaffold (similar to native aortic valve leaflets) and also reduced its compaction. We determined that the composite scaffolds supported the growth of human aortic valve interstitial cells (HAVIC), balanced the remodeling of heart valve ECM against shrinkage, and maintained better physiological fibroblastic phenotype in both normal and diseased HAVIC over single materials. These fabricated composite scaffolds enable the engineering of a living heart valve graft with improved anisotropic structure and tissue biomechanics important for maintaining valve cell phenotypes. Heart valve-related disease is an important clinical problem, with over 300,000 surgical repairs performed annually. Tissue engineering offers a promising strategy for heart valve repair and regeneration. In this study, we developed and tissue engineered living nano-micro fibrous woven fabric/hydrogel composite scaffolds by using textile technique combined with bioactive hydrogel formation. The novelty of our technique is that the composite scaffolds can mimic physical structure anisotropy and the mechanical strength of natural aortic valve leaflet. Moreover, the composite scaffolds prevented the matrix shrinkage, which is major problem that causes the failure of TEHV, and better maintained physiological fibroblastic phenotype in both normal and diseased HAVIC. This work marks the first report of a combination composite scaffold using 3D hydrogel enhanced by nano-micro fibrous woven fabric, and represents a promising tissue engineering strategy to treat heart valve injury. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Altitude-Limiting Airbrake System for Small to Medium Scale Rockets

NASA Technical Reports Server (NTRS)

Aaron, Robert F., III

2013-01-01

The goal of the overall internship opportunity this semester was to learn and practice the elements of engineering design through direct exposure to real engineering problems. The primary exposure was to design and manufacture an airbrake device for use with small-medium scale rocket applications. The idea was to take the presented concept of a solution and transform said concept into a reliable fully-functioning and reusable mechanism. The mechanism was to be designed as an insurance feature so that the overall altitude of a rocket with relatively undetermined engine capabilities does not unexpectedly exceed the imposed 10,000 foot ceiling, per range requirements. The airbrake concept was introduced to the Prototype Development Lab as a rotation-driven four tiered offset track pin mechanism, i.e. the airbrake was deployed by rotating a central shaft attached directly to the bottom plate. The individual airbrake fins were subsequently deployed using multiple plates with tracks of offset curvature. The fins were created with guide pins to follow the tracks in each of the offset plates, thus allowing the simultaneous rotational deployment of all fins by only rotating one plate. The concept of this solution was great; though it did not function in application. The rotating plates alone brought up problems like the entire back half of the rocket rotating according to the motion of the aforementioned base plate. Subsequently, the solution currently under development became a static linear actuator-driven spring-loaded fin release system. This solution is almost instantaneously triggered electronically when the avionics detect that the rocket has reached the calculated altitude of deceleration. This altitude will allow enough time remaining to the overall ceiling to adequately decelerate the rocket prior to reaching the ceiling.

Mechanical Design of Innovative Electromagnetic Linear Actuators for Marine Applications

NASA Astrophysics Data System (ADS)

Muscia, Roberto

2017-11-01

We describe an engineering solution to manufacture electromagnetic linear actuators for moving rudders and fin stabilizers of military shipsItalian Ministry of Defence, General Direction of Naval Equipments (NAVARM), Projects ISO (2012-2014) and EDDA (2015-2017). . The solution defines the transition from the conceptual design of the device initially studied from an electromagnetic point of view to mechanical configurations that really work. The structural problems that have been resolved with the proposed configuration are described. In order to validate the design choices discussed we illustrate some results of the numerical simulations performed by the structural finite elements method. These results quantitatively justify the suggested mechanical solution by evaluating stresses and deformations in a virtual prototype of the structure during its functioning. The parts of the device that have been studied are the most critical because in cases of excessive deformation/stress, they can irreparably compromise the actuator operation. These parts are the pole piece-base set and the retention cages of the permanent magnets. The FEM analysis has allowed us to identify the most stressed areas of the previous elements whose shape has been appropriately designed so as to reduce the maximum stresses and deformations. Moreover, the FEM analysis helped to find the most convenient solution to join the pole pieces to the respective bases. The good results obtained by the suggested engineering solution have been experimentally confirmed by tests on a small prototype actuator purposely manufactured. Finally, a qualitative analysis of the engineering problems that have to be considered to design electromagnetic linear actuators bigger than the one already manufactured is illustrated.

Evolutionary decay and the prospects for long-term disease intervention using engineered insect vectors

PubMed Central

2015-01-01

After a long history of applying the sterile insect technique to suppress populations of disease vectors and agricultural pests, there is growing interest in using genetic engineering both to improve old methods and to enable new methods. The two goals of interventions are to suppress populations, possibly eradicating a species altogether, or to abolish the vector’s competence to transmit a parasite. New methods enabled by genetic engineering include the use of selfish genes toward either goal as well as a variety of killer-rescue systems that could be used for vector competence reduction. This article reviews old and new methods with an emphasis on the potential for evolution of resistance to these strategies. Established methods of population suppression did not obviously face a problem from resistance evolution, but newer technologies might. Resistance to these newer interventions will often be mechanism-specific, and while it is too early to know where resistance evolution will become a problem, it is at least possible to propose properties of interventions that will be more or less effective in blocking resistance evolution. PMID:26160736

Core skills assessment to improve mathematical competency

NASA Astrophysics Data System (ADS)

Carr, Michael; Bowe, Brian; Fhloinn, Eabhnat Ní

2013-12-01

Many engineering undergraduates begin third-level education with significant deficiencies in their core mathematical skills. Every year, in the Dublin Institute of Technology, a diagnostic test is given to incoming first-year students, consistently revealing problems in basic mathematics. It is difficult to motivate students to address these problems; instead, they struggle through their degree, carrying a serious handicap of poor core mathematical skills, as confirmed by exploratory testing of final year students. In order to improve these skills, a pilot project was set up in which a 'module' in core mathematics was developed. The course material was basic, but 90% or higher was required to pass. Students were allowed to repeat this module throughout the year by completing an automated examination on WebCT populated by a question bank. Subsequent to the success of this pilot with third-year mechanical engineering students, the project was extended to five different engineering programmes, across three different year-groups. Full results and analysis of this project are presented, including responses to interviews carried out with a selection of the students involved.

Bioengineering approaches to study multidrug resistance in tumor cells

PubMed Central

Fallica, Brian; Makin, Guy

2015-01-01

The ability of cancer cells to become resistant to chemotherapeutic agents is a major challenge for the treatment of malignant tumors. Several strategies have emerged to attempt to inhibit chemoresistance, but the fact remains that resistance is a problem for every effective anticancer drug. The first part of this review will focus on the mechanisms of chemoresistance. It is important to understand the environmental cues, transport limitations and the cellular signaling pathways associated with chemoresistance before we can hope to effectively combat it. The second part of this review focuses on the work that needs to be done moving forward. Specifically, this section focuses on the necessity of translational research and interdisciplinary directives. It is critical that the expertise of oncologists, biologists, and engineers be brought together to attempt to tackle the problem. This discussion is from an engineering perspective, as the dialogue between engineers and other cancer researchers is the most challenging due to non-overlapping background knowledge. Chemoresistance is a complex and devastating process, meaning that we urgently need sophisticated methods to study the process of how cells become resistant. PMID:21387035

Mechanical properties and structure-function relationships of human chondrocyte-seeded cartilage constructs after in vitro culture.

PubMed

Middendorf, Jill M; Griffin, Darvin J; Shortkroff, Sonya; Dugopolski, Caroline; Kennedy, Stephen; Siemiatkoski, Joseph; Cohen, Itai; Bonassar, Lawrence J

2017-10-01

Autologous Chondrocyte Implantation (ACI) is a widely recognized method for the repair of focal cartilage defects. Despite the accepted use, problems with this technique still exist, including graft hypertrophy, damage to surrounding tissue by sutures, uneven cell distribution, and delamination. Modified ACI techniques overcome these challenges by seeding autologous chondrocytes onto a 3D scaffold and securing the graft into the defect. Many studies on these tissue engineered grafts have identified the compressive properties, but few have examined frictional and shear properties as suggested by FDA guidance. This study is the first to perform three mechanical tests (compressive, frictional, and shear) on human tissue engineered cartilage. The objective was to understand the complex mechanical behavior, function, and changes that occur with time in these constructs grown in vitro using compression, friction, and shear tests. Safranin-O histology and a DMMB assay both revealed increased sulfated glycosaminoglycan (sGAG) content in the scaffolds with increased maturity. Similarly, immunohistochemistry revealed increased lubricin localization on the construct surface. Confined compression and friction tests both revealed improved properties with increased construct maturity. Compressive properties correlated with the sGAG content, while improved friction coefficients were attributed to increased lubricin localization on the construct surfaces. In contrast, shear properties did not improve with increased culture time. This study suggests the various mechanical and biological properties of tissue engineered cartilage improve at different rates, indicating thorough mechanical evaluation of tissue engineered cartilage is critical to understanding the performance of repaired cartilage. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2298-2306, 2017. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Pipe Flow Simulation Software: A Team Approach to Solve an Engineering Education Problem.

ERIC Educational Resources Information Center

Engel, Renata S.; And Others

1996-01-01

A computer simulation program for use in the study of fluid mechanics is described. The package is an interactive tool to explore the fluid flow characteristics of a pipe system by manipulating the physical construction of the system. The motivation, software design requirements, and specific details on how its objectives were met are presented.…

Mobile Dwelling Unit Developed by a Group of Mechanical Engineering Design Students

ERIC Educational Resources Information Center

Novak, Marina; Pozun, Matjaz; Dolsak, Bojan; Pocivavsek, Tadej

2004-01-01

The increasing number of homeless people is one of the most burning problems of nowadays world. Society has to find the way to fight against it and provide help to those people that have no place to stay. For short-term interventions, the application of the mobile dwelling units seems to be the only possible solution. However, existing mobile…

Application of multicriteria decision making methods to compression ignition engine efficiency and gaseous, particulate, and greenhouse gas emissions.

PubMed

Surawski, Nicholas C; Miljevic, Branka; Bodisco, Timothy A; Brown, Richard J; Ristovski, Zoran D; Ayoko, Godwin A

2013-02-19

Compression ignition (CI) engine design is subject to many constraints, which present a multicriteria optimization problem that the engine researcher must solve. In particular, the modern CI engine must not only be efficient but must also deliver low gaseous, particulate, and life cycle greenhouse gas emissions so that its impact on urban air quality, human health, and global warming is minimized. Consequently, this study undertakes a multicriteria analysis, which seeks to identify alternative fuels, injection technologies, and combustion strategies that could potentially satisfy these CI engine design constraints. Three data sets are analyzed with the Preference Ranking Organization Method for Enrichment Evaluations and Geometrical Analysis for Interactive Aid (PROMETHEE-GAIA) algorithm to explore the impact of (1) an ethanol fumigation system, (2) alternative fuels (20% biodiesel and synthetic diesel) and alternative injection technologies (mechanical direct injection and common rail injection), and (3) various biodiesel fuels made from 3 feedstocks (i.e., soy, tallow, and canola) tested at several blend percentages (20-100%) on the resulting emissions and efficiency profile of the various test engines. The results show that moderate ethanol substitutions (~20% by energy) at moderate load, high percentage soy blends (60-100%), and alternative fuels (biodiesel and synthetic diesel) provide an efficiency and emissions profile that yields the most "preferred" solutions to this multicriteria engine design problem. Further research is, however, required to reduce reactive oxygen species (ROS) emissions with alternative fuels and to deliver technologies that do not significantly reduce the median diameter of particle emissions.

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.

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.

Gesellschaft fuer angewandte Mathematik und Mechanik, Scientific Annual Meeting, Universitaet Stuttgart, Federal Republic of Germany, Apr. 13-17, 1987, Reports

NASA Astrophysics Data System (ADS)

Recent experimental, theoretical, and numerical investigations of problems in applied mechanics are discussed in reviews and reports. The fields covered include vibration and stability; the mechanics of elastic and plastic materials; fluid mechanics; the numerical treatment of differential equations; finite and boundary elements; optimization, decision theory, stochastics, and actuarial analysis; applied analysis and mathematical physics; and numerical analysis. Reviews are presented on mathematical applications of geometric-optics methods, biomechanics and implant technology, vibration theory in engineering, the stiffness and strength of damaged materials, and the existence of slow steady flows of viscoelastic fluids of integral type.

Out-of-plane (SH) soil-structure interaction: a shear wall with rigid and flexible ring foundation

NASA Astrophysics Data System (ADS)

Le, Thang; Lee, Vincent W.; Luo, Hao

2016-02-01

Soil-structure interaction (SSI) of a building and shear wall above a foundation in an elastic half-space has long been an important research subject for earthquake engineers and strong-motion seismologists. Numerous papers have been published since the early 1970s; however, very few of these papers have analytic closed-form solutions available. The soil-structure interaction problem is one of the most classic problems connecting the two disciplines of earthquake engineering and civil engineering. The interaction effect represents the mechanism of energy transfer and dissipation among the elements of the dynamic system, namely the soil subgrade, foundation, and superstructure. This interaction effect is important across many structure, foundation, and subgrade types but is most pronounced when a rigid superstructure is founded on a relatively soft lower foundation and subgrade. This effect may only be ignored when the subgrade is much harder than a flexible superstructure: for instance a flexible moment frame superstructure founded on a thin compacted soil layer on top of very stiff bedrock below. This paper will study the interaction effect of the subgrade and the superstructure. The analytical solution of the interaction of a shear wall, flexible-rigid foundation, and an elastic half-space is derived for incident SH waves with various angles of incidence. It found that the flexible ring (soft layer) cannot be used as an isolation mechanism to decouple a superstructure from its substructure resting on a shaking half-space.

The Problem of Ensuring Reliability of Gas Turbine Engines

NASA Astrophysics Data System (ADS)

Nozhnitsky, Yu A.

2018-01-01

Requirements to advanced engines for civil aviation are discussing. Some significant problems of ensuring reliability of advanced gas turbine engines are mentioned. Special attention is paid to successful utilization of new materials and critical technologies. Also the problem of excluding failure of engine part due to low cycle or high cycle fatigue is discussing.

How To Solve Problems. For Success in Freshman Physics, Engineering, and Beyond. Third Edition.

ERIC Educational Resources Information Center

Scarl, Donald

To expertly solve engineering and science problems one needs to know science and engineering as well as have a tool kit of problem-solving methods. This book is about problem-solving methods: it presents the methods professional problem solvers use, explains why these methods have evolved, and shows how a student can make these methods his/her…

A reverse engineering algorithm for neural networks, applied to the subthalamopallidal network of basal ganglia.

PubMed

Floares, Alexandru George

2008-01-01

Modeling neural networks with ordinary differential equations systems is a sensible approach, but also very difficult. This paper describes a new algorithm based on linear genetic programming which can be used to reverse engineer neural networks. The RODES algorithm automatically discovers the structure of the network, including neural connections, their signs and strengths, estimates its parameters, and can even be used to identify the biophysical mechanisms involved. The algorithm is tested on simulated time series data, generated using a realistic model of the subthalamopallidal network of basal ganglia. The resulting ODE system is highly accurate, and results are obtained in a matter of minutes. This is because the problem of reverse engineering a system of coupled differential equations is reduced to one of reverse engineering individual algebraic equations. The algorithm allows the incorporation of common domain knowledge to restrict the solution space. To our knowledge, this is the first time a realistic reverse engineering algorithm based on linear genetic programming has been applied to neural networks.

Validation of High-Fidelity CFD Simulations for Rocket Injector Design

NASA Technical Reports Server (NTRS)

Tucker, P. Kevin; Menon, Suresh; Merkle, Charles L.; Oefelein, Joseph C.; Yang, Vigor

2008-01-01

Computational fluid dynamics (CFD) has the potential to improve the historical rocket injector design process by evaluating the sensitivity of performance and injector-driven thermal environments to the details of the injector geometry and key operational parameters. Methodical verification and validation efforts on a range of coaxial injector elements have shown the current production CFD capability must be improved in order to quantitatively impact the injector design process. This paper documents the status of a focused effort to compare and understand the predictive capabilities and computational requirements of a range of CFD methodologies on a set of single element injector model problems. The steady Reynolds-Average Navier-Stokes (RANS), unsteady Reynolds-Average Navier-Stokes (URANS) and three different approaches using the Large Eddy Simulation (LES) technique were used to simulate the initial model problem, a single element coaxial injector using gaseous oxygen and gaseous hydrogen propellants. While one high-fidelity LES result matches the experimental combustion chamber wall heat flux very well, there is no monotonic convergence to the data with increasing computational tool fidelity. Systematic evaluation of key flow field regions such as the flame zone, the head end recirculation zone and the downstream near wall zone has shed significant, though as of yet incomplete, light on the complex, underlying causes for the performance level of each technique. 1 Aerospace Engineer and Combustion CFD Team Leader, MS ER42, NASA MSFC, AL 35812, Senior Member, AIAA. 2 Professor and Director, Computational Combustion Laboratory, School of Aerospace Engineering, 270 Ferst Dr., Atlanta, GA 30332, Associate Fellow, AIAA. 3 Reilly Professor of Engineering, School of Mechanical Engineering, 585 Purdue Mall, West Lafayette, IN 47907, Fellow, AIAA. 4 Principal Member of Technical Staff, Combustion Research Facility, 7011 East Avenue, MS9051, Livermore, CA 94550, Associate Fellow, AIAA. 5 J. L. and G. H. McCain Endowed Chair, Mechanical Engineering, 104 Research Building East, University Park, PA 16802, Fellow, AIAA. American Institute of Aeronautics and Astronautics 1

Professional development for design-based learning in engineering education: a case study

NASA Astrophysics Data System (ADS)

Gómez Puente, Sonia M.; van Eijck, Michiel; Jochems, Wim

2015-01-01

Design-based learning (DBL) is an educational approach in which students gather and apply theoretical knowledge to solve design problems. In this study, we examined how critical DBL dimensions (project characteristics, design elements, the teacher's role, assessment, and social context) are applied by teachers in the redesign of DBL projects. We conducted an intervention for the professional development of the DBL teachers in the Mechanical Engineering and the Electrical Engineering departments. We used the Experiential Learning Cycle as an educational model for the professionalisation programme. The findings show that the programme encouraged teachers to apply the DBL theoretical framework. However, there are some limitations with regard to specific project characteristics. Further research into supporting teachers to develop open-ended and multidisciplinary activities in the projects that support learning is recommended.

Practice on Upbringing Young Engineers Collaborated with Local Enterprises

NASA Astrophysics Data System (ADS)

Hiraki, Yutaka; Uno, Naotsugu; Tanaka, Yuichi; Iyama, Hirofumi; Yamashita, Toru; Miyamoto, Noritaka

The ministry of Economics and Industry started the project collaborated with National Colleges of Technology titled “Upbringing Young Engineers in small and medium-sized enterprises” , in 2006. In our college, the authors planed the upbringing-program for the die-cast engineer in automobile industries collaborated with several enterprises in neighboring area and applied for the project. The program was adopted and worked out the concrete curriculum for the first year. The curriculum contains the training of the base of mechanical design with 3D-CAD/CAE/CAM systems and the practical training on manufacturing, by means of Problem Based Learning method. The program carried out in September and finished in December successfully. This paper reports the outline of the curriculum and the results in the program.

Definition of the Engineering Method.

ERIC Educational Resources Information Center

Koen, Billy Vaughn

In an effort to more clearly define the engineering method, this document attempts to draw distinctions between engineering and science. Part I, "Some Thoughts on Engineering," discusses strategies that engineers employ to solve problems, and the characteristics of the types of engineering problems. Part II, "The Principal Rule of the Engineering…

Seeing through the lens of social justice: A threshold for engineering

NASA Astrophysics Data System (ADS)

Kabo, Jens David

In recent times the need for educational research dedicated to engineering education has been recognised. This PhD project is a contribution to the development of engineering education scholarship and the growing body of engineering education research. In this project it was recognised that problem solving is a central activity to engineering. However, it was also recognised that the conditions for doing engineering are changing, especially in light of pressing issues of poverty and environmental sustainability that humanity currently faces, and as a consequence, engineering education needs to emphasise problem definition to a greater extent. One mechanism for achieving this, which has been adopted by some engineering educators in recent years, is through courses that explicitly relate engineering to social justice. However, creating this relationship requires critical interdisciplinary thinking that is alien to most engineering students. In this dissertation it is suggested that for engineering students, and more generally, engineers, looking at their practice and profession through a social justice lens might be seen as a threshold that needs to be crossed. By studying the variation present among students in three different courses at three different North American universities, the intention was to understand how students approach and internalise social justice as a perspective on engineering and/or develop their abilities to think critically. A conceptual model to frame the study was developed by combining elements of threshold concept theory and the educational research methodology, phenomenographic variation theory. All three of the courses studied operated on a similar basic pedagogical model, however, the courses were framed differently, with social justice in the foreground or in the background with the focus on, in one case, ethics and in the other, sustainability. All courses studied appeared to be successful in encouraging engineering students to engage in critical thinking and a similar general trend in the development of students' conceptions of social justice was observed in each of the three courses. However, it does appear that if one is interested in developing an articulated understanding of social justice, with respect to engineering, that an explicit focus on social justice is preferable.

Conformal mapping for multiple terminals

PubMed Central

Wang, Weimin; Ma, Wenying; Wang, Qiang; Ren, Hao

2016-01-01

Conformal mapping is an important mathematical tool that can be used to solve various physical and engineering problems in many fields, including electrostatics, fluid mechanics, classical mechanics, and transformation optics. It is an accurate and convenient way to solve problems involving two terminals. However, when faced with problems involving three or more terminals, which are more common in practical applications, existing conformal mapping methods apply assumptions or approximations. A general exact method does not exist for a structure with an arbitrary number of terminals. This study presents a conformal mapping method for multiple terminals. Through an accurate analysis of boundary conditions, additional terminals or boundaries are folded into the inner part of a mapped region. The method is applied to several typical situations, and the calculation process is described for two examples of an electrostatic actuator with three electrodes and of a light beam splitter with three ports. Compared with previously reported results, the solutions for the two examples based on our method are more precise and general. The proposed method is helpful in promoting the application of conformal mapping in analysis of practical problems. PMID:27830746

Multiphysics Code Demonstrated for Propulsion Applications

NASA Technical Reports Server (NTRS)

Lawrence, Charles; Melis, Matthew E.

1998-01-01

The utility of multidisciplinary analysis tools for aeropropulsion applications is being investigated at the NASA Lewis Research Center. The goal of this project is to apply Spectrum, a multiphysics code developed by Centric Engineering Systems, Inc., to simulate multidisciplinary effects in turbomachinery components. Many engineering problems today involve detailed computer analyses to predict the thermal, aerodynamic, and structural response of a mechanical system as it undergoes service loading. Analysis of aerospace structures generally requires attention in all three disciplinary areas to adequately predict component service behavior, and in many cases, the results from one discipline substantially affect the outcome of the other two. There are numerous computer codes currently available in the engineering community to perform such analyses in each of these disciplines. Many of these codes are developed and used in-house by a given organization, and many are commercially available. However, few, if any, of these codes are designed specifically for multidisciplinary analyses. The Spectrum code has been developed for performing fully coupled fluid, thermal, and structural analyses on a mechanical system with a single simulation that accounts for all simultaneous interactions, thus eliminating the requirement for running a large number of sequential, separate, disciplinary analyses. The Spectrum code has a true multiphysics analysis capability, which improves analysis efficiency as well as accuracy. Centric Engineering, Inc., working with a team of Lewis and AlliedSignal Engines engineers, has been evaluating Spectrum for a variety of propulsion applications including disk quenching, drum cavity flow, aeromechanical simulations, and a centrifugal compressor flow simulation.

Quantum-classical transition of photon-Carnot engine induced by quantum decoherence

NASA Astrophysics Data System (ADS)

Quan, H. T.; Zhang, P.; Sun, C. P.

2006-03-01

We study the physical implementation of the photon-Carnot engine (PCE) based on the cavity quantum electrodynamics system [M. O. Scully, M. Suhail Zubairy, G. S. Agarwal, and H. Walther, Science 299, 862 (2003)]. Here we analyze two decoherence mechanisms for the more practical systems of PCE, the dissipation of photon field, and the pure dephasing of the input atoms. As a result we find that (i) the PCE can work well to some extent even in the existence of the cavity loss (photon dissipation) and (ii) the short-time atomic dephasing, which can destroy the PCE, is a fatal problem to be overcome.

Controls and guidance research

NASA Technical Reports Server (NTRS)

Homaifar, Abdollah; Dunn, Derome; Song, Yong-Duan; Lai, Steven H.-Y.

1992-01-01

The objectives of the control group are concentrated on research and education. The control problem of the hypersonic space vehicle represents an important and challenging issue in aerospace engineering. The work described in this report is part of our effort in developing advanced control strategies for such a system. In order to achieve the objectives stated in the NASA-CORE proposal, the tasks were divided among the group based upon their educational expertise. Within the educational component we are offering a Linear Systems and Control course for students in electrical and mechanical engineering. Also, we are proposing a new course in Digital Control Systems with a corresponding laboratory.

Simulation by bondgraphs

NASA Astrophysics Data System (ADS)

Thoma, Jean Ulrich

The fundamental principles and applications of the bond graph method, in which a system is represented on paper by letter elements and their interconnections (bonds), are presented in an introduction for engineering students. Chapters are devoted to simulation and graphical system models; bond graphs as networks for power and signal exchange; the simulation and design of mechanical engineering systems; the simulation of fluid power systems and hydrostatic devices; electrical circuits, drives, and components; practical procedures and problems of bond-graph-based numerical simulation; and applications to thermodynamics, chemistry, and biology. Also included are worked examples of applications to robotics, shocks and collisions, ac circuits, hydraulics, and a hydropneumatic fatigue-testing machine.

Bulk Metallic Glasses and Composites for Optical and Compliant Mechanisms

NASA Technical Reports Server (NTRS)

Hofmann, Douglas C.; Agnes, Gregory S.

2013-01-01

Mechanisms are used widely in engineering applications due to their ability to translate force and movement. They are found in kinematic pairs, gears, cams, linkages, and in flexure mechanisms (also known as compliant mechanisms). Mechanisms and flexures are used widely in spacecraft design, especially in the area of optics, where precise positioning of telescope mirrors requires elastic flexing of elements. A compliant mechanism is generally defined as a flexible mechanism that uses an elastic body deformation to cause a displacement (such as positing a mirror). The mechanisms are usually constructed as a single monolithic piece of material, and contain thin struts to allow for large elastic bending with low input force. This creates the largest problem with developing precise mechanisms; they must be fabricated from a single piece of metal, but are required to have strict accuracy on their dimensions. They are generally required to have high strength, elasticity, and low coefficient of thermal expansion.

Gesellschaft fuer angewandte Mathematik und Mechanik, Scientific Annual Meeting, Universitaet Stuttgart, Federal Republic of Germany, Apr. 13-17, 1987, Reports

NASA Astrophysics Data System (ADS)

Recent advances in the analytical and numerical treatment of physical and engineering problems are discussed in reviews and reports. Topics addressed include fluid mechanics, numerical methods for differential equations, FEM approaches, and boundary-element methods. Consideration is given to optimization, decision theory, stochastics, actuarial mathematics, applied mathematics and mathematical physics, and numerical analysis.

Application of Summability Methods to Jackson Theorems for Splines.

DTIC Science & Technology

1984-06-30

principal investigator Dr. Louise Paphael of the Department of Mathematics, Howard University investigated three major problems in the areas of...Differential Equations, August 1983. c) Howard University , Department of Mechanical Engineering, October 1983. d) AMS meeting, San Luis Obispo, Ca., Special...Session on Partial Differen- tial Equations, November 1983. e) Bryn Mawr College, Pa., Fourier Series Seminar, December 1983. f) Howard University , Department

Numerical Analysis of a Class of THM Coupled Model for Porous Materials

NASA Astrophysics Data System (ADS)

Liu, Tangwei; Zhou, Jingying; Lu, Hongzhi

2018-01-01

We consider the coupled models of the Thermo-hydro-mechanical (THM) problem for porous materials which arises in many engineering applications. Firstly, mathematical models of the THM coupled problem for porous materials were discussed. Secondly, for different cases, some numerical difference schemes of coupled model were constructed, respectively. Finally, aassuming that the original water vapour effect is neglectable and that the volume fraction of liquid phase and the solid phase are constants, the nonlinear equations can be reduced to linear equations. The discrete equations corresponding to the linear equations were solved by the Arnodli method.

Extrusion Process by Finite Volume Method Using OpenFoam Software

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

Matos Martins, Marcelo; Tonini Button, Sergio; Divo Bressan, Jose

The computational codes are very important tools to solve engineering problems. In the analysis of metal forming process, such as extrusion, this is not different because the computational codes allow analyzing the process with reduced cost. Traditionally, the Finite Element Method is used to solve solid mechanic problems, however, the Finite Volume Method (FVM) have been gaining force in this field of applications. This paper presents the velocity field and friction coefficient variation results, obtained by numerical simulation using the OpenFoam Software and the FVM to solve an aluminum direct cold extrusion process.

General Electric I-40 Engine at the Lewis Flight Propulsion Laboratory

NASA Image and Video Library

1946-08-21

A mechanic works on a General Electric I-40 turbojet at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. The military selected General Electric’s West Lynn facility in 1941 to secretly replicate the centrifugal turbojet engine designed by British engineer Frank Whittle. General Electric’s first attempt, the I-A, was fraught with problems. The design was improved somewhat with the subsequent I-16 engine. It was not until the engine's next reincarnation as the I-40 in 1943 that General Electric’s efforts paid off. The 4000-pound thrust I-40 was incorporated into the Lockheed Shooting Star airframe and successfully flown in June 1944. The Shooting Star became the US’s first successful jet aircraft and the first US aircraft to reach 500 miles per hour. The NACA’s Lewis Flight Propulsion Laboratory studied all of General Electric’s centrifugal turbojets both during World War II and afterwards. The entire Shooting Star aircraft was investigated in the Altitude Wind Tunnel during 1945. The researchers studied the engine compressor performance, thrust augmentation using a water injection, and compared different fuel blends in a single combustor. The mechanic in this photograph is inserting a combustion liner into one of the 14 combustor cans. The compressor, which is not yet installed in this photograph, pushed high pressure air into these combustors. There the air mixed with the fuel and was heated. The hot air was then forced through a rotating turbine that powered the engine before being expelled out the nozzle to produce thrust.

Maintenance problems associated with the operation of the F402 /Pegasus/ engine in the AV-8A /Harrier/ aircraft

NASA Technical Reports Server (NTRS)

Stanley, C. W.; Hood, W. E.

1981-01-01

The U.S. Marine Corp (USMC) has been operating the only V/STOL attack aircraft in the western world since 1971. Some of the maintenance problems experienced are related to the unique V/STOL design criteria of the Pegasus engine. However, the major part of the required maintenance effort is found to involve the more conventional engine problems. A description of the aircraft engine is provided and the problems resulting from V/STOL design demands are examined. Attention is given to the fuel system control, the engine air bleed, foreign object damage to the hp compressor, and the engine exhaust system.

Fundamentals of tribology at the atomic level

NASA Technical Reports Server (NTRS)

Ferrante, John; Pepper, Stephen V.

1989-01-01

Tribology, the science and engineering of solid surfaces in moving contact, is a field that encompasses many disciplines: solid state physics, chemistry, materials science, and mechanical engineering. In spite of the practical importance and maturity of the field, the fundamental understanding of basic phenomena has only recently been attacked. An attempt to define some of these problems and indicate some profitable directions for future research is presented. There are three broad classifications: (1) fluid properties (compression, rheology, additives and particulates); (2) material properties of the solids (deformation, defect formation and energy loss mechanisms); and (3) interfacial properties (adhesion, friction chemical reactions, and boundary films). Research in the categories has traditionally been approached by considering macroscopic material properties. Recent activity has shown that some issues can be approached at the atomic level: the atoms in the materials can be manipulated both experimentally and theoretically, and can produce results related to macroscopic phenomena.

Teamwork Seminar Practice to Foster Diversified Thinking and Leadership Among Students

NASA Astrophysics Data System (ADS)

Maruyama, Naoki; Yoshida, Kazumi; Yamao, Hidenori

A new course entitled “Mechanical Engineering Seminar” has begun in the Department of Mechanical Engineering, Mie University. This course consists of three parts, a teamwork seminar, a creative design seminar and a comprehensive achievement examination. Its aim is to foster a broad social and international outlook, ethical thinking, autonomy, partnership, leadership, presentation ability, originality, overall creativity in students, and to help them become aware of their real ability. The teaching method used in this seminar is based on problem-based learning (PBL) , and pro-active student participation is required. The purpose of this paper is to report the features, teaching method and educational effectiveness of the teamwork seminar, which seeks to educate students with a broad, diversified outlook. The results of a student questionnaire show that these new fields of study stimulate students' will to learn, and they express general satisfaction with the seminar.

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...

Perm State University HPC-hardware and software services: capabilities for aircraft engine aeroacoustics problems solving

NASA Astrophysics Data System (ADS)

Demenev, A. G.

2018-02-01

The present work is devoted to analyze high-performance computing (HPC) infrastructure capabilities for aircraft engine aeroacoustics problems solving at Perm State University. We explore here the ability to develop new computational aeroacoustics methods/solvers for computer-aided engineering (CAE) systems to handle complicated industrial problems of engine noise prediction. Leading aircraft engine engineering company, including “UEC-Aviadvigatel” JSC (our industrial partners in Perm, Russia), require that methods/solvers to optimize geometry of aircraft engine for fan noise reduction. We analysed Perm State University HPC-hardware resources and software services to use efficiently. The performed results demonstrate that Perm State University HPC-infrastructure are mature enough to face out industrial-like problems of development CAE-system with HPC-method and CFD-solvers.

Group Design Problems in Engineering Design Graphics.

ERIC Educational Resources Information Center

Kelley, David

2001-01-01

Describes group design techniques used within the engineering design graphics sequence at Western Washington University. Engineering and design philosophies such as concurrent engineering place an emphasis on group collaboration for the solving of design problems. (Author/DDR)

Engineering and public health at CDC.

PubMed

Earnest, G Scott; Reed, Laurence D; Conover, D; Estill, C; Gjessing, C; Gressel, M; Hall, R; Hudock, S; Hudson, H; Kardous, C; Sheehy, J; Topmiller, J; Trout, D; Woebkenberg, M; Amendola, A; Hsiao, H; Keane, P; Weissman, D; Finfinger, G; Tadolini, S; Thimons, E; Cullen, E; Jenkins, M; McKibbin, R; Conway, G; Husberg, B; Lincoln, J; Rodenbeck, S; Lantagne, D; Cardarelli, J

2006-12-22

Engineering is the application of scientific and technical knowledge to solve human problems. Using imagination, judgment, and reasoning to apply science, technology, mathematics, and practical experience, engineers develop the design, production, and operation of useful objects or processes. During the 1940s, engineers dominated the ranks of CDC scientists. In fact, the first CDC director, Assistant Surgeon General Mark Hollis, was an engineer. CDC engineers were involved in malaria control through the elimination of standing water. Eventually the CDC mission expanded to include prevention and control of dengue, typhus, and other communicable diseases. The development of chlorination, water filtration, and sewage treatment were crucial to preventing waterborne illness. Beginning in the 1950s, CDC engineers began their work to improve public health while developing the fields of environmental health, industrial hygiene, and control of air pollution. Engineering disciplines represented at CDC today include biomedical, civil, chemical, electrical, industrial, mechanical, mining, and safety engineering. Most CDC engineers are located in the National Institute for Occupational Safety and Health (NIOSH) and the Agency for Toxic Substances and Disease Registry (ATSDR). Engineering research at CDC has a broad stakeholder base. With the cooperation of industry, labor, trade associations, and other stakeholders and partners, current work includes studies of air contaminants, mining, safety, physical agents, ergonomics, and environmental hazards. Engineering solutions remain a cornerstone of the traditional "hierarchy of controls" approach to reducing public health hazards.

Problem Solving and Engineering Design, Introducing Bachelor Students to Engineering Practice at K. U. Leuven

ERIC Educational Resources Information Center

Heylen, Christel; Smet, Marc; Buelens, Hermans; Sloten, Jos Vander

2007-01-01

A present-day engineer has a large scientific knowledge; he is a team-player, eloquent communicator and life-long learner. At the Katholieke Universiteit Leuven, the course "Problem Solving and Engineering Design" introduces engineering students from the first semester onwards into real engineering practice and teamwork. Working in small…

40 CFR 89.102 - Effective dates, optional inclusion, flexibility for equipment manufacturers.

Code of Federal Regulations, 2010 CFR

2010-07-01

... exemptions for technical or engineering hardship. You may request additional engine allowances under... technical or engineering problems that prevent you from meeting the requirements of this part. You must show... your engine supplier to design products. (iii) Describe the engineering or technical problems causing...

40 CFR 89.102 - Effective dates, optional inclusion, flexibility for equipment manufacturers.

Code of Federal Regulations, 2013 CFR

2013-07-01

... exemptions for technical or engineering hardship. You may request additional engine allowances under... technical or engineering problems that prevent you from meeting the requirements of this part. You must show... your engine supplier to design products. (iii) Describe the engineering or technical problems causing...

40 CFR 89.102 - Effective dates, optional inclusion, flexibility for equipment manufacturers.

Code of Federal Regulations, 2012 CFR

2012-07-01

... exemptions for technical or engineering hardship. You may request additional engine allowances under... technical or engineering problems that prevent you from meeting the requirements of this part. You must show... your engine supplier to design products. (iii) Describe the engineering or technical problems causing...

Construction Strategy and Progress of Whole Intervertebral Disc Tissue Engineering.

PubMed

Yang, Qiang; Xu, Hai-wei; Hurday, Sookesh; Xu, Bao-shan

2016-02-01

Degenerative disc disease (DDD) is the major cause of low back pain, which usually leads to work absenteeism, medical visits and hospitalization. Because the current conservative procedures and surgical approaches to treatment of DDD only aim to relieve the symptoms of disease but not to regenerate the diseased disc, their long-term efficiency is limited. With the rapid developments in medical science, tissue engineering techniques have progressed markedly in recent years, providing a novel regenerative strategy for managing intervertebral disc disease. However, there are as yet no ideal methods for constructing tissue-engineered intervertebral discs. This paper reviews published reports pertaining to intervertebral disc tissue engineering and summarizes data concerning the seed cells and scaffold materials for tissue-engineered intervertebral discs, construction of tissue-engineered whole intervertebral discs, relevant animal experiments and effects of mechanics on the construction of tissue-engineered intervertebral disc and outlines the existing problems and future directions. Although the perfect regenerative strategy for treating DDD has not yet been developed, great progress has been achieved in the construction of tissue-engineered intervertebral discs. It is believed that ongoing research on intervertebral disc tissue engineering will result in revolutionary progress in the treatment of DDD. © 2016 Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.

Chemistry and the Internal Combustion Engine II: Pollution Problems.

ERIC Educational Resources Information Center

Hunt, C. B.

1979-01-01

Discusses pollution problems which arise from the use of internal combustion (IC) engines in the United Kingdom (UK). The IC engine exhaust emissions, controlling IC engine pollution in the UK, and some future developments are also included. (HM)

Matrix methods applied to engineering rigid body mechanics

NASA Astrophysics Data System (ADS)

Crouch, T.

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

Differential Cloud Particles Evolution Algorithm Based on Data-Driven Mechanism for Applications of ANN

PubMed Central

2017-01-01

Computational scientists have designed many useful algorithms by exploring a biological process or imitating natural evolution. These algorithms can be used to solve engineering optimization problems. Inspired by the change of matter state, we proposed a novel optimization algorithm called differential cloud particles evolution algorithm based on data-driven mechanism (CPDD). In the proposed algorithm, the optimization process is divided into two stages, namely, fluid stage and solid stage. The algorithm carries out the strategy of integrating global exploration with local exploitation in fluid stage. Furthermore, local exploitation is carried out mainly in solid stage. The quality of the solution and the efficiency of the search are influenced greatly by the control parameters. Therefore, the data-driven mechanism is designed for obtaining better control parameters to ensure good performance on numerical benchmark problems. In order to verify the effectiveness of CPDD, numerical experiments are carried out on all the CEC2014 contest benchmark functions. Finally, two application problems of artificial neural network are examined. The experimental results show that CPDD is competitive with respect to other eight state-of-the-art intelligent optimization algorithms. PMID:28761438

On-road and wind-tunnel measurement of motorcycle helmet noise.

PubMed

Kennedy, J; Carley, M; Walker, I; Holt, N

2013-09-01

The noise source mechanisms involved in motorcycling include various aerodynamic sources and engine noise. The problem of noise source identification requires extensive data acquisition of a type and level that have not previously been applied. Data acquisition on track and on road are problematic due to rider safety constraints and the portability of appropriate instrumentation. One way to address this problem is the use of data from wind tunnel tests. The validity of these measurements for noise source identification must first be demonstrated. In order to achieve this extensive wind tunnel tests have been conducted and compared with the results from on-track measurements. Sound pressure levels as a function of speed were compared between on track and wind tunnel tests and were found to be comparable. Spectral conditioning techniques were applied to separate engine and wind tunnel noise from aerodynamic noise and showed that the aerodynamic components were equivalent in both cases. The spectral conditioning of on-track data showed that the contribution of engine noise to the overall noise is a function of speed and is more significant than had previously been thought. These procedures form a basis for accurate experimental measurements of motorcycle noise.

Fault Tree in the Trenches, A Success Story

NASA Technical Reports Server (NTRS)

Long, R. Allen; Goodson, Amanda (Technical Monitor)

2000-01-01

Getting caught up in the explanation of Fault Tree Analysis (FTA) minutiae is easy. In fact, most FTA literature tends to address FTA concepts and methodology. Yet there seems to be few articles addressing actual design changes resulting from the successful application of fault tree analysis. This paper demonstrates how fault tree analysis was used to identify and solve a potentially catastrophic mechanical problem at a rocket motor manufacturer. While developing the fault tree given in this example, the analyst was told by several organizations that the piece of equipment in question had been evaluated by several committees and organizations, and that the analyst was wasting his time. The fault tree/cutset analysis resulted in a joint-redesign of the control system by the tool engineering group and the fault tree analyst, as well as bragging rights for the analyst. (That the fault tree found problems where other engineering reviews had failed was not lost on the other engineering groups.) Even more interesting was that this was the analyst's first fault tree which further demonstrates how effective fault tree analysis can be in guiding (i.e., forcing) the analyst to take a methodical approach in evaluating complex systems.

On the Use of Accelerated Test Methods for Characterization of Advanced Composite Materials

NASA Technical Reports Server (NTRS)

Gates, Thomas S.

2003-01-01

A rational approach to the problem of accelerated testing for material characterization of advanced polymer matrix composites is discussed. The experimental and analytical methods provided should be viewed as a set of tools useful in the screening of material systems for long-term engineering properties in aerospace applications. Consideration is given to long-term exposure in extreme environments that include elevated temperature, reduced temperature, moisture, oxygen, and mechanical load. Analytical formulations useful for predictive models that are based on the principles of time-based superposition are presented. The need for reproducible mechanisms, indicator properties, and real-time data are outlined as well as the methodologies for determining specific aging mechanisms.

Inflationary dynamics for matrix eigenvalue problems

PubMed Central

Heller, Eric J.; Kaplan, Lev; Pollmann, Frank

2008-01-01

Many fields of science and engineering require finding eigenvalues and eigenvectors of large matrices. The solutions can represent oscillatory modes of a bridge, a violin, the disposition of electrons around an atom or molecule, the acoustic modes of a concert hall, or hundreds of other physical quantities. Often only the few eigenpairs with the lowest or highest frequency (extremal solutions) are needed. Methods that have been developed over the past 60 years to solve such problems include the Lanczos algorithm, Jacobi–Davidson techniques, and the conjugate gradient method. Here, we present a way to solve the extremal eigenvalue/eigenvector problem, turning it into a nonlinear classical mechanical system with a modified Lagrangian constraint. The constraint induces exponential inflationary growth of the desired extremal solutions. PMID:18511564

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...

Study on Calculation Model of Culvert Soil Pressure

NASA Astrophysics Data System (ADS)

Liu, Jing; Tian, Xiao-yan; Gao, Xiao-mei

2017-09-01

Culvert diseases are prevalent in highway engineering. There are many factors involved in the occurrence of the disease, and the problem is complex. However, the design cannot accurately determine the role of the soil pressure on the culvert is the main reason to the disease. Based on the theoretical analysis and field test, this paper studies the characteristics of the stress and deformation of the culvert-soil structure. According to the theory of soil mechanics, the calculation model of vertical soil pressure at the top of culvert is determined, and the formula of vertical soil pressure at the top of culvert is deduced. Through the field test of the vertical soil pressure at the top of culvert of several engineering examples, the calculation formula of this paper is verified, which can provide reference for future practical engineering.

Mass drivers. 3: Engineering

NASA Technical Reports Server (NTRS)

Arnold, W.; Bowen, S.; Cohen, S.; Fine, K.; Kaplan, D.; Kolm, M.; Kolm, H.; Newman, J.; Oneill, G. K.; Snow, W.

1979-01-01

The last of a series of three papers by the Mass-Driver Group of the 1977 Ames Summer Study is presented. It develops the engineering principles required to implement the basic mass-driver. Optimum component mass trade-offs are derived from a set of four input parameters, and the program used to design a lunar launcher. The mass optimization procedures is then incorporated into a more comprehensive mission optimization program called OPT-4, which evaluates an optimized mass-driver reaction engine and its performance in a range of specified missions. Finally, this paper discusses, to the extent that time permitted, certain peripheral problems: heating effects in buckets due to magnetic field ripple; an approximate derivation of guide force profiles; the mechanics of inserting and releasing payloads; the reaction mass orbits; and a proposed research and development plan for implementing mass drivers.

Role of Airway Recruitment and Derecruitment in Lung Injury

PubMed Central

Ghadiali, S. N.; Huang, Y.

2011-01-01

The mechanical forces generated during the ventilation of patients with acute lung injury causes significant lung damage and inflammation. Low-volume ventilation protocols are commonly used to prevent stretch-related injury that occurs at high lung volumes. However, the cyclic closure and reopening of pulmonary airways at low lung volumes, i.e., derecruitment and recruitment, also causes significant lung damage and inflammation. In this review, we provide an overview of how biomedical engineering techniques are being used to elucidate the complex physiological and biomechanical mechanisms responsible for cellular injury during recruitment/derecruitment. We focus on the development of multiscale, multiphysics computational models of cell deformation and injury during airway reopening. These models, and the corresponding in vitro experiments, have been used to both elucidate the basic mechanisms responsible for recruitment/derecruitment injury and to develop alternative therapies that make the epithelium more resistant to injury. For example, models and experiments indicate that fluidization of the cytoskeleton is cytoprotective and that changes in cytoskeletal structure and cell mechanics can be used to mitigate the mechanotransduction of oscillatory pressure into inflammatory signaling. The continued application of biomedical engineering techniques to the problem of recruitment/derecruitment injury may therefore lead to novel and more effective therapies. PMID:22011235

Research Technology

NASA Image and Video Library

2001-08-01

The electro-mechanical actuator, a new electronics technology, is an electronic system that provides the force needed to move valves that control the flow of propellant to the engine. It is proving to be advantageous for the main propulsion system plarned for a second generation reusable launch vehicle. Hydraulic actuators have been used successfully in rocket propulsion systems. However, they can leak when high pressure is exerted on such a fluid-filled hydraulic system. Also, hydraulic systems require significant maintenance and support equipment. The electro-mechanical actuator is proving to be low maintenance and the system weighs less than a hydraulic system. The electronic controller is a separate unit powering the actuator. Each actuator has its own control box. If a problem is detected, it can be replaced by simply removing one defective unit. The hydraulic systems must sustain significant hydraulic pressures in a rocket engine regardless of demand. The electro-mechanical actuator utilizes power only when needed. A goal of the Second Generation Reusable Launch Vehicle Program is to substantially improve safety and reliability while reducing the high cost of space travel. The electro-mechanical actuator was developed by the Propulsion Projects Office of the Second Generation Reusable Launch Vehicle Program at the Marshall Space Flight Center.

Introductory Level Problems Illustrating Concepts in Pharmaceutical Engineering

ERIC Educational Resources Information Center

McIver, Keith; Whitaker, Kathryn; De Delva, Vladimir; Farrell, Stephanie; Savelski, Mariano J.; Slater, C. Stewart

2012-01-01

Textbook style problems including detailed solutions introducing pharmaceutical topics at the level of an introductory chemical engineering course have been created. The problems illustrate and teach subjects which students would learn if they were to pursue a career in pharmaceutical engineering, including the unique terminology of the field,…

Enhanced and Conventional Project-Based Learning in an Engineering Design Module

ERIC Educational Resources Information Center

Chua, K. J.; Yang, W. M.; Leo, H. L.

2014-01-01

Engineering education focuses chiefly on students' ability to solve problems. While most engineering students are proficient in solving paper questions, they may not be proficient at providing optimal solutions to pragmatic project-based problems that require systematic learning strategy, innovation, problem-solving, and execution. The…

Complementary hydro-mechanical coupled finite/discrete element and microseismic modelling to predict hydraulic fracture propagation in tight shale reservoirs

NASA Astrophysics Data System (ADS)

Profit, Matthew; Dutko, Martin; Yu, Jianguo; Cole, Sarah; Angus, Doug; Baird, Alan

2016-04-01

This paper presents a novel approach to predict the propagation of hydraulic fractures in tight shale reservoirs. Many hydraulic fracture modelling schemes assume that the fracture direction is pre-seeded in the problem domain discretisation. This is a severe limitation as the reservoir often contains large numbers of pre-existing fractures that strongly influence the direction of the propagating fracture. To circumvent these shortcomings, a new fracture modelling treatment is proposed where the introduction of discrete fracture surfaces is based on new and dynamically updated geometrical entities rather than the topology of the underlying spatial discretisation. Hydraulic fracturing is an inherently coupled engineering problem with interactions between fluid flow and fracturing when the stress state of the reservoir rock attains a failure criterion. This work follows a staggered hydro-mechanical coupled finite/discrete element approach to capture the key interplay between fluid pressure and fracture growth. In field practice, the fracture growth is hidden from the design engineer and microseismicity is often used to infer hydraulic fracture lengths and directions. Microseismic output can also be computed from changes of the effective stress in the geomechanical model and compared against field microseismicity. A number of hydraulic fracture numerical examples are presented to illustrate the new technology.

Applications of fuzzy theories to multi-objective system optimization

NASA Technical Reports Server (NTRS)

Rao, S. S.; Dhingra, A. K.

1991-01-01

Most of the computer aided design techniques developed so far deal with the optimization of a single objective function over the feasible design space. However, there often exist several engineering design problems which require a simultaneous consideration of several objective functions. This work presents several techniques of multiobjective optimization. In addition, a new formulation, based on fuzzy theories, is also introduced for the solution of multiobjective system optimization problems. The fuzzy formulation is useful in dealing with systems which are described imprecisely using fuzzy terms such as, 'sufficiently large', 'very strong', or 'satisfactory'. The proposed theory translates the imprecise linguistic statements and multiple objectives into equivalent crisp mathematical statements using fuzzy logic. The effectiveness of all the methodologies and theories presented is illustrated by formulating and solving two different engineering design problems. The first one involves the flight trajectory optimization and the main rotor design of helicopters. The second one is concerned with the integrated kinematic-dynamic synthesis of planar mechanisms. The use and effectiveness of nonlinear membership functions in fuzzy formulation is also demonstrated. The numerical results indicate that the fuzzy formulation could yield results which are qualitatively different from those provided by the crisp formulation. It is felt that the fuzzy formulation will handle real life design problems on a more rational basis.

Biologically and mechanically driven design of an RGD-mimetic macroporous foam for adipose tissue engineering applications.

PubMed

Rossi, Eleonora; Gerges, Irini; Tocchio, Alessandro; Tamplenizza, Margherita; Aprile, Paola; Recordati, Camilla; Martello, Federico; Martin, Ivan; Milani, Paolo; Lenardi, Cristina

2016-10-01

Despite clinical treatments for adipose tissue defects, in particular breast tissue reconstruction, have certain grades of efficacy, many drawbacks are still affecting the long-term survival of new formed fat tissue. To overcome this problem, in the last decades, several scaffolding materials have been investigated in the field of adipose tissue engineering. However, a strategy able to recapitulate a suitable environment for adipose tissue reconstruction and maintenance is still missing. To address this need, we adopted a biologically and mechanically driven design to fabricate an RGD-mimetic poly(amidoamine) oligomer macroporous foam (OPAAF) for adipose tissue reconstruction. The scaffold was designed to fulfil three fundamental criteria: capability to induce cell adhesion and proliferation, support of in vivo vascularization and match of native tissue mechanical properties. Poly(amidoamine) oligomers were formed into soft scaffolds with hierarchical porosity through a combined free radical polymerization and foaming reaction. OPAAF is characterized by a high water uptake capacity, progressive degradation kinetics and ideal mechanical properties for adipose tissue reconstruction. OPAAF's ability to support cell adhesion, proliferation and adipogenesis was assessed in vitro using epithelial, fibroblast and endothelial cells (MDCK, 3T3L1 and HUVEC respectively). In addition, in vivo subcutaneous implantation in murine model highlighted OPAAF potential to support both adipogenesis and vessels infiltration. Overall, the reported results support the use of OPAAF as a scaffold for engineered adipose tissue construct. Copyright © 2016 Elsevier Ltd. All rights reserved.

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...

Opportunities in Mechnical Engineering. [VGM Career Horizons Series].

ERIC Educational Resources Information Center

Konzo, Seichi; Bayne, James W.

This book presents information on career opportunities in mechanical engineering. Chapter 1 describes the historical development of mechanical engineering and its interactions with society, considers the growth of the American Society of Mechanical Engineers, and discusses the relevance of mechanical engineering to present-day and future society.…

Stress transmission through a model system of cohesionless elastic grains

NASA Astrophysics Data System (ADS)

Da Silva, Miguel; Rajchenbach, Jean

2000-08-01

Understanding the mechanical properties of granular materials is important for applications in civil and chemical engineering, geophysical sciences and the food industry, as well as for the control or prevention of avalanches and landslides. Unlike continuous media, granular materials lack cohesion, and cannot resist tensile stresses. Current descriptions of the mechanical properties of collections of cohesionless grains have relied either on elasto-plastic models classically used in civil engineering, or on a recent model involving hyperbolic equations. The former models suggest that collections of elastic grains submitted to a compressive load will behave elastically. Here we present the results of an experiment on a two-dimensional model system-made of discrete square cells submitted to a point load-in which the region in which the stress is confined is photoelastically visualized as a parabola. These results, which can be interpreted within a statistical framework, demonstrate that the collective response of the pile contradicts the standard elastic predictions and supports a diffusive description of stress transmission. We expect that these findings will be applicable to problems in soil mechanics, such as the behaviour of cohesionless soils or sand piles.

A Hybrid Symbiotic Organisms Search Algorithm with Variable Neighbourhood Search for Solving Symmetric and Asymmetric Traveling Salesman Problem

NASA Astrophysics Data System (ADS)

Umam, M. I. H.; Santosa, B.

2018-04-01

Combinatorial optimization has been frequently used to solve both problems in science, engineering, and commercial applications. One combinatorial problems in the field of transportation is to find a shortest travel route that can be taken from the initial point of departure to point of destination, as well as minimizing travel costs and travel time. When the distance from one (initial) node to another (destination) node is the same with the distance to travel back from destination to initial, this problems known to the Traveling Salesman Problem (TSP), otherwise it call as an Asymmetric Traveling Salesman Problem (ATSP). The most recent optimization techniques is Symbiotic Organisms Search (SOS). This paper discuss how to hybrid the SOS algorithm with variable neighborhoods search (SOS-VNS) that can be applied to solve the ATSP problem. The proposed mechanism to add the variable neighborhoods search as a local search is to generate the better initial solution and then we modify the phase of parasites with adapting mechanism of mutation. After modification, the performance of the algorithm SOS-VNS is evaluated with several data sets and then the results is compared with the best known solution and some algorithm such PSO algorithm and SOS original algorithm. The SOS-VNS algorithm shows better results based on convergence, divergence and computing time.

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. ...

Biology and genetic engineering of fruit maturation for enhanced quality and shelf-life.

PubMed

Matas, Antonio J; Gapper, Nigel E; Chung, Mi-Young; Giovannoni, James J; Rose, Jocelyn K C

2009-04-01

Commercial regulation of ripening is currently achieved through early harvest, by controlling the postharvest storage atmosphere and genetic selection for slow or late ripening varieties. Although these approaches are often effective, they are not universally applicable and often result in acceptable, but poor quality, products. With increased understanding of the molecular biology underlying ripening and the advent of genetic engineering technologies, researchers have pursued new strategies to address problems in fruit shelf-life and quality. These have been guided by recent insights into mechanisms by which ethylene and a complex network of transcription factors regulate ripening, and by an increased appreciation of factors that contribute to shelf-life, such as the fruit cuticle.

A Fractional PDE Approach to Turbulent Mixing; Part II: Numerical Simulation

NASA Astrophysics Data System (ADS)

Samiee, Mehdi; Zayernouri, Mohsen

2016-11-01

We propose a generalizing fractional order transport model of advection-diffusion kind with fractional time- and space-derivatives, governing the evolution of passive scalar turbulence. This approach allows one to incorporate the nonlocal and memory effects in the underlying anomalous diffusion i.e., sub-to-standard diffusion to model the trapping of particles inside the eddied, and super-diffusion associated with the sudden jumps of particles from one coherent region to another. For this nonlocal model, we develop a high order numerical (spectral) method in addition to a fast solver, examined in the context of some canonical problems. PhD student, Department of Mechanical Engineering, & Department Computational Mathematics, Science, and Engineering.

Geotechnical behavior of the MSW in Tianziling landfill.

PubMed

Zhu, Xiang-Rong; Jin, Jian-Min; Fang, Peng-Fei

2003-01-01

The valley shaped Tianziling landfill of Hangzhou in China built in 1991 to dispose of municipal solid waste (MSW) was designed for a service life of 13 years. The problem of waste landfill slope stability and expansion must be considered from the geotechnical engineering point of view, for which purpose, it is necessary to understand the geotechnical properties of the MSW in the landfill, some of whose physical properties were measured by common geotechnical tests, such as those on unit weight, water content, organic matter content, specific gravity, coefficient of permeability, compressibility, etc. The mechanical properties were studied by direct shear test, triaxial compression test, and static and dynamic penetration tests. Some strength parameters for engineering analysis were obtained.

Effect of a "Look-Ahead" Problem on Undergraduate Engineering Students' Concept Comprehension

ERIC Educational Resources Information Center

Goodman, Kevin; Davis, Julian; McDonald, Thomas

2016-01-01

In an effort to motivate undergraduate engineering students to prepare for class by reviewing material before lectures, a "Look-Ahead" problem was utilized. Students from two undergraduate engineering courses; Statics and Electronic Circuits, were assigned problems from course material that had not yet been covered in class. These…

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

Rocketdyne LOX bearing tester program

NASA Technical Reports Server (NTRS)

Keba, J. E.; Beatty, R. F.

1988-01-01

The cause, or causes, for the Space Shuttle Main Engine ball wear were unknown, however, several mechanisms were suspected. Two testers were designed and built for operation in liquid oxygen to empirically gain insight into the problems and iterate solutions in a timely and cost efficient manner independent of engine testing. Schedules and test plans were developed that defined a test matrix consisting of parametric variations of loading, cooling or vapor margin, cage lubrication, material, and geometry studies. Initial test results indicated that the low pressure pump thrust bearing surface distress is a function of high axial load. Initial high pressure turbopump bearing tests produced the wear phenomenon observed in the turbopump and identified an inadequate vapor margin problem and a coolant flowrate sensitivity issue. These tests provided calibration data of analytical model predictions to give high confidence in the positive impact of future turbopump design modification for flight. Various modifications will be evaluated in these testers, since similar turbopump conditions can be produced and the benefit of the modification will be quantified in measured wear life comparisons.

Averting Denver Airports on a Chip

NASA Technical Reports Server (NTRS)

Sullivan, Kevin J.

1995-01-01

As a result of recent advances in software engineering capabilities, we are now in a more stable environment. De-facto hardware and software standards are emerging. Work on software architecture and design patterns signals a consensus on the importance of early system-level design decisions, and agreements on the uses of certain paradigmatic software structures. We now routinely build systems that would have been risky or infeasible a few years ago. Unfortunately, technological developments threaten to destabilize software design again. Systems designed around novel computing and peripheral devices will spark ambitious new projects that will stress current software design and engineering capabilities. Micro-electro-mechanical systems (MEMS) and related technologies provide the physical basis for new systems with the potential to produce this kind of destabilizing effect. One important response to anticipated software engineering and design difficulties is carefully directed engineering-scientific research. Two specific problems meriting substantial research attention are: A lack of sufficient means to build software systems by generating, extending, specializing, and integrating large-scale reusable components; and a lack of adequate computational and analytic tools to extend and aid engineers in maintaining intellectual control over complex software designs.

Metabolic engineering for microbial production and applications of copolyesters consisting of 3-hydroxybutyrate and medium-chain-length 3-hydroxyalkanoates.

PubMed

Zou, Xiang Hui; Chen, Guo-Qiang

2007-02-12

Poly(hydroxyalkanoate)s (PHAs) are a class of microbially synthesized polyesters that combine biological properties, such as biocompatibility and biodegradability, and non-bioproperties such as thermoprocessability, piezoelectricity, and nonlinear optical activity. PHA monomer structures and their contents strongly affect the PHA properties. Using metabolic engineering approaches, PHA structures and contents can be manipulated to achieve controllable monomer and PHA cellular contents. This paper focuses on metabolic engineering methods to produce PHA consisting of 3-hydroxybutyrate (3HB) and medium-chain-length 3-hydroxyalkanoates (3HA) in recombinant microbial systems. This type of copolyester has mechanical and thermal properties similar to conventional plastics such as poly(propylene) and poly(ethylene terephthalate) (PET). In addition, pathways containing engineered PHA synthases have proven to be useful for enhanced PHA production with adjustable PHA monomers and contents. The applications of PHA as implant biomaterials are briefly discussed here. In the very near term, metabolic engineering will help solve many problems in promoting PHA as a new type of plastic material for many applications.

New course in bioengineering and bioinspired design.

PubMed

Erickson, Jonathan C

2012-01-01

The past two years, a new interdisciplinary course has been offered at Washington and Lee University (Lexington, VA, USA), which seeks to surmount barriers that have traditionally existed between the physical and life sciences. The course explores the physiology leading to the physical mechanisms and engineering principles that endow the astonishing navigation abilities and sensory mechanisms of animal systems. The course also emphasizes how biological systems are inspiring novel engineering designs. Two (among many) examples are how the adhesion of the gecko foot inspired a new class of adhesives based on Van der Waals forces; and how the iridophore protein plates found in mimic octopus and squid act as tunable ¼ wave stacks, thus inspiring the engineering of optically tunable block copolymer gels for sensing temperature, pressure, or chemical gradients. A major component of this course is the integration of a 6-8 week long research project. To date, projects have included engineering: a soft-body robot whose motion mimics the inchworm; an electrical circuit to sense minute electric fields in aqueous environments based on the shark electrosensory system; and cyborg grasshoppers whose jump motion is controlled via an electronic-neural interface. Initial feedback has indicated that this course has served to increase student interaction and “cross-pollination” of ideas between the physical and life sciences. Student feedback also indicated a marked increase in desire and confidence to continue to pursue problems at the boundary of biology and engineering—bioengineering.

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.

Modernizing engine displays

NASA Technical Reports Server (NTRS)

Schneider, E. T.; Enevoldson, E. K.

1984-01-01

The introduction of electronic fuel control to modern turbine engines has a number of advantages, which are related to an increase in engine performance and to a reduction or elimination of the problems associated with high angle of attack engine operation from the surface to 50,000 feet. If the appropriate engine display devices are available to the pilot, the fuel control system can provide a great amount of information. Some of the wealth of information available from modern fuel controls are discussed in this paper. The considered electronic engine control systems in their most recent forms are known as the Full Authority Digital Engine Control (FADEC) and the Digital Electronic Engine Control (DEEC). Attention is given to some details regarding the control systems, typical engine problems, the solution of problems with the aid of displays, engine displays in normal operation, an example display format, a multipage format, flight strategies, and hardware considerations.

High-Performance Parallel Analysis of Coupled Problems for Aircraft Propulsion

NASA Technical Reports Server (NTRS)

Felippa, C. A.; Farhat, C.; Park, K. C.; Gumaste, U.; Chen, P.-S.; Lesoinne, M.; Stern, P.

1996-01-01

This research program dealt with the application of high-performance computing methods to the numerical simulation of complete jet engines. The program was initiated in January 1993 by applying two-dimensional parallel aeroelastic codes to the interior gas flow problem of a bypass jet engine. The fluid mesh generation, domain decomposition and solution capabilities were successfully tested. Attention was then focused on methodology for the partitioned analysis of the interaction of the gas flow with a flexible structure and with the fluid mesh motion driven by these structural displacements. The latter is treated by a ALE technique that models the fluid mesh motion as that of a fictitious mechanical network laid along the edges of near-field fluid elements. New partitioned analysis procedures to treat this coupled three-component problem were developed during 1994 and 1995. These procedures involved delayed corrections and subcycling, and have been successfully tested on several massively parallel computers, including the iPSC-860, Paragon XP/S and the IBM SP2. For the global steady-state axisymmetric analysis of a complete engine we have decided to use the NASA-sponsored ENG10 program, which uses a regular FV-multiblock-grid discretization in conjunction with circumferential averaging to include effects of blade forces, loss, combustor heat addition, blockage, bleeds and convective mixing. A load-balancing preprocessor tor parallel versions of ENG10 was developed. During 1995 and 1996 we developed the capability tor the first full 3D aeroelastic simulation of a multirow engine stage. This capability was tested on the IBM SP2 parallel supercomputer at NASA Ames. Benchmark results were presented at the 1196 Computational Aeroscience meeting.

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

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

Kornreich, Drew E; Vaidya, Rajendra U; Ammerman, Curtt N

Integrated Computational Materials Engineering (ICME) is a novel overarching approach to bridge length and time scales in computational materials science and engineering. This approach integrates all elements of multi-scale modeling (including various empirical and science-based models) with materials informatics to provide users the opportunity to tailor material selections based on stringent application needs. Typically, materials engineering has focused on structural requirements (stress, strain, modulus, fracture toughness etc.) while multi-scale modeling has been science focused (mechanical threshold strength model, grain-size models, solid-solution strengthening models etc.). Materials informatics (mechanical property inventories) on the other hand, is extensively data focused. All of thesemore » elements are combined within the framework of ICME to create architecture for the development, selection and design new composite materials for challenging environments. We propose development of the foundations for applying ICME to composite materials development for nuclear and high-radiation environments (including nuclear-fusion energy reactors, nuclear-fission reactors, and accelerators). We expect to combine all elements of current material models (including thermo-mechanical and finite-element models) into the ICME framework. This will be accomplished through the use of a various mathematical modeling constructs. These constructs will allow the integration of constituent models, which in tum would allow us to use the adaptive strengths of using a combinatorial scheme (fabrication and computational) for creating new composite materials. A sample problem where these concepts are used is provided in this summary.« less

Interactive simulations as teaching tools for engineering mechanics courses

NASA Astrophysics Data System (ADS)

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

2013-07-01

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

Quasi-stationary mechanics of elastic continua with bending stiffness wrapping on a pulley system

NASA Astrophysics Data System (ADS)

Kaczmarczyk, S.; Mirhadizadeh, S.

2016-05-01

In many engineering applications elastic continua such as ropes and belts often are subject to bending when they pass over pulleys / sheaves. In this paper the quasi-stationary mechanics of a cable-pulley system is studied. The cable is modelled as a moving Euler- Bernoulli beam. The distribution of tension is non-uniform along its span and due to the bending stiffness the contact points at the pulley-beam boundaries are not unknown. The system is described by a set of nonlinear ordinary differential equations with undetermined boundary conditions. The resulting nonlinear Boundary Value Problem (BVP) with unknown boundaries is solved by converting the problem into the ‘standard’ form defined over a fixed interval. Numerical results obtained for a range of typical configurations with relevant boundary conditions applied demonstrate that due to the effects of bending stiffness the angels of wrap are reduced and the span tensions are increased.

Application of microdynamics and lattice mechanics to problems in plastic flow and fracture. Final report, 1 April 1973--31 March 1978

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

Bilello, J C; Liu, J M

Progress in an investigation of the application of microdynamics and lattice mechanics to the problems in plastic flow and fracture is described. The research program consisted of both theoretical formulations and experimental measurements of a number of intrinsic material parameters in bcc metals and alloys including surface energy, phonon-dispersion curves for dislocated solids, dislocation-point defect interaction energy, slip initiation and microplastic flow behavior. The study has resulted in an improved understanding in the relationship among the experimentally determined fracture surface energy, the intrinsic cohesive energy between atomic planes, and the plastic deformation associated with the initial stages of crack propagation.more » The values of intrinsic surface energy of tungsten, molybdenum, niobium and niobium-molybdenum alloys, deduced from the measurements, serve as a starting point from which fracture toughness of these materials in engineering service may be intelligently discussed.« less

Modelling of deformation process for the layer of elastoviscoplastic media under surface action of periodic force of arbitrary type

NASA Astrophysics Data System (ADS)

Mikheyev, V. V.; Saveliev, S. V.

2018-01-01

Description of deflected mode for different types of materials under action of external force plays special role for wide variety of applications - from construction mechanics to circuits engineering. This article con-siders the problem of plastic deformation of the layer of elastoviscolastic soil under surface periodic force. The problem was solved with use of the modified lumped parameters approach which takes into account close to real distribution of normal stress in the depth of the layer along with changes in local mechanical properties of the material taking place during plastic deformation. Special numeric algorithm was worked out for computer modeling of the process. As an example of application suggested algorithm was realized for the deformation of the layer of elasoviscoplastic material by the source of external lateral force with the parameters of real technological process of soil compaction.

Intelligent Mining Engineering Systems in the Structure of Industry 4.0

NASA Astrophysics Data System (ADS)

Rylnikova, Marina; Radchenko, Dmitriy; Klebanov, Dmitriy

2017-11-01

The solution of the problem of improving the human environment and working conditions at mines is based on the provision of the rationale of parameters and conditions for the implementation of an environmentally balanced cycle of comprehensive development of mineral deposits on the basis of the design of mining engineering systems characterized by the minimization of the human factor effect in danger zones of mining operations. In this area, robotized technologies are being developed, machinery and mechanisms with the elements of artificial intelligence, and mining and transport system automatic controls are being put into service throughout the world. In the upcoming decades, mining machines and mechanisms will be virtually industrial robots. The article presents the results of zoning of open-pit and underground mine production areas, as well as mining engineering system of combined development depending on the fact and periodicity of human presence in zones of mining processes. As a surface geotechnology case study, the software structure based on a modular concept is described. The performance philosophy of mining and transport equipment with the elements of artificial intelligence is shown when it is put into service in an open pit.

Web-Based Problem-Solving Assignment and Grading System

NASA Astrophysics Data System (ADS)

Brereton, Giles; Rosenberg, Ronald

2014-11-01

In engineering courses with very specific learning objectives, such as fluid mechanics and thermodynamics, it is conventional to reinforce concepts and principles with problem-solving assignments and to measure success in problem solving as an indicator of student achievement. While the modern-day ease of copying and searching for online solutions can undermine the value of traditional assignments, web-based technologies also provide opportunities to generate individualized well-posed problems with an infinite number of different combinations of initial/final/boundary conditions, so that the probability of any two students being assigned identical problems in a course is vanishingly small. Such problems can be designed and programmed to be: single or multiple-step, self-grading, allow students single or multiple attempts; provide feedback when incorrect; selectable according to difficulty; incorporated within gaming packages; etc. In this talk, we discuss the use of a homework/exam generating program of this kind in a single-semester course, within a web-based client-server system that ensures secure operation.

Engineering management of large scale systems

NASA Technical Reports Server (NTRS)

Sanders, Serita; Gill, Tepper L.; Paul, Arthur S.

1989-01-01

The organization of high technology and engineering problem solving, has given rise to an emerging concept. Reasoning principles for integrating traditional engineering problem solving with system theory, management sciences, behavioral decision theory, and planning and design approaches can be incorporated into a methodological approach to solving problems with a long range perspective. Long range planning has a great potential to improve productivity by using a systematic and organized approach. Thus, efficiency and cost effectiveness are the driving forces in promoting the organization of engineering problems. Aspects of systems engineering that provide an understanding of management of large scale systems are broadly covered here. Due to the focus and application of research, other significant factors (e.g., human behavior, decision making, etc.) are not emphasized but are considered.

The Problem of Engineering Creativity in Russia: A Critical Review

ERIC Educational Resources Information Center

Kukushkin, Sergey; Churlyaeva, Natalya

2012-01-01

The problem of technological creativity in Russia is briefly discussed. Special attention is paid to the development of indigenous engineering corpus in unfavourable conditions and some reasons for engineers' low creativity are revealed. The Soviet system of engineering higher education (HE) is criticised as not focused on fostering creative…

Teaching Agile Software Engineering Using Problem-Based Learning

ERIC Educational Resources Information Center

El-Khalili, Nuha H.

2013-01-01

Many studies have reported the utilization of Problem-Based Learning (PBL) in teaching Software Engineering courses. However, these studies have different views of the effectiveness of PBL. This paper presents the design of an Advanced Software Engineering course for undergraduate Software Engineering students that uses PBL to teach them Agile…

Pre-Engineering Program. Introduction to Engineering. Advanced Engineering.

ERIC Educational Resources Information Center

Henrico County Public Schools, Glen Allen, VA. Virginia Vocational Curriculum and Resource Center.

This guide contains information and hands-on activities to guide students through the problem-solving process needed in engineering (problem solving, presentation, and impact analysis) and information to help the instructor manage the program or courses in Virginia. Following an introduction, the guide contains a program description that supplies…

Providing Formative Assessment to Students Solving Multipath Engineering Problems with Complex Arrangements of Interacting Parts: An Intelligent Tutor Approach

ERIC Educational Resources Information Center

Steif, Paul S.; Fu, Luoting; Kara, Levent Burak

2016-01-01

Problems faced by engineering students involve multiple pathways to solution. Students rarely receive effective formative feedback on handwritten homework. This paper examines the potential for computer-based formative assessment of student solutions to multipath engineering problems. In particular, an intelligent tutor approach is adopted and…

Promoting Collaborative Problem-Solving Skills in a Course on Engineering Grand Challenges

ERIC Educational Resources Information Center

Zou, Tracy X. P.; Mickleborough, Neil C.

2015-01-01

The ability to solve problems with people of diverse backgrounds is essential for engineering graduates. A course on engineering grand challenges was designed to promote collaborative problem-solving (CPS) skills. One unique component is that students need to work both within their own team and collaborate with the other team to tackle engineering…

Rocket Engine Oscillation Diagnostics

NASA Technical Reports Server (NTRS)

Nesman, Tom; Turner, James E. (Technical Monitor)

2002-01-01

Rocket engine oscillating data can reveal many physical phenomena ranging from unsteady flow and acoustics to rotordynamics and structural dynamics. Because of this, engine diagnostics based on oscillation data should employ both signal analysis and physical modeling. This paper describes an approach to rocket engine oscillation diagnostics, types of problems encountered, and example problems solved. Determination of design guidelines and environments (or loads) from oscillating phenomena is required during initial stages of rocket engine design, while the additional tasks of health monitoring, incipient failure detection, and anomaly diagnostics occur during engine development and operation. Oscillations in rocket engines are typically related to flow driven acoustics, flow excited structures, or rotational forces. Additional sources of oscillatory energy are combustion and cavitation. Included in the example problems is a sampling of signal analysis tools employed in diagnostics. The rocket engine hardware includes combustion devices, valves, turbopumps, and ducts. Simple models of an oscillating fluid system or structure can be constructed to estimate pertinent dynamic parameters governing the unsteady behavior of engine systems or components. In the example problems it is shown that simple physical modeling when combined with signal analysis can be successfully employed to diagnose complex rocket engine oscillatory phenomena.

Editors' overview perspectives on teaching social responsibility to students in science and engineering.

PubMed

Zandvoort, Henk; Børsen, Tom; Deneke, Michael; Bird, Stephanie J

2013-12-01

Global society is facing formidable current and future problems that threaten the prospects for justice and peace, sustainability, and the well-being of humanity both now and in the future. Many of these problems are related to science and technology and to how they function in the world. If the social responsibility of scientists and engineers implies a duty to safeguard or promote a peaceful, just and sustainable world society, then science and engineering education should empower students to fulfil this responsibility. The contributions to this special issue present European examples of teaching social responsibility to students in science and engineering, and provide examples and discussion of how this teaching can be promoted, and of obstacles that are encountered. Speaking generally, education aimed at preparing future scientists and engineers for social responsibility is presently very limited and seemingly insufficient in view of the enormous ethical and social problems that are associated with current science and technology. Although many social, political and professional organisations have expressed the need for the provision of teaching for social responsibility, important and persistent barriers stand in the way of its sustained development. What is needed are both bottom-up teaching initiatives from individuals or groups of academic teachers, and top-down support to secure appropriate embedding in the university. Often the latter is lacking or inadequate. Educational policies at the national or international level, such as the Bologna agreements in Europe, can be an opportunity for introducing teaching for social responsibility. However, frequently no or only limited positive effect of such policies can be discerned. Existing accreditation and evaluation mechanisms do not guarantee appropriate attention to teaching for social responsibility, because, in their current form, they provide no guarantee that the curricula pay sufficient attention to teaching goals that are desirable for society as a whole.

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

Space shuttle main engine controller assembly, phase C-D. [with lagging system design and analysis

NASA Technical Reports Server (NTRS)

1973-01-01

System design and system analysis and simulation are slightly behind schedule, while design verification testing has improved. Input/output circuit design has improved, but digital computer unit (DCU) and mechanical design continue to lag. Part procurement was impacted by delays in printed circuit board, assembly drawing releases. These are the result of problems in generating suitable printed circuit artwork for the very complex and high density multilayer boards.

Some remarks on the numerical solution of parabolic partial differential equations

NASA Astrophysics Data System (ADS)

Campagna, R.; Cuomo, S.; Leveque, S.; Toraldo, G.; Giannino, F.; Severino, G.

2017-11-01

Numerous environmental/engineering applications relying upon the theory of diffusion phenomena into chaotic environments have recently stimulated the interest toward the numerical solution of parabolic partial differential equations (PDEs). In the present paper, we outline a formulation of the mathematical problem underlying a quite general diffusion mechanism in the natural environments, and we shortly emphasize some remarks concerning the applicability of the (straightforward) finite difference method. An illustration example is also presented.

Experimental and Computational Studies of Heat Transfer in Complex Internal Flows.

DTIC Science & Technology

1981-01-01

project, extending from September 15, 1979 to December 15, 1980 . The details of five distinct pieces of research are set forth. These research problems... Hislop , C. I., and Morris, R., "Effect on the Local Heat Transfer Coefficient in a Pipe of an Abrupt Disturbance of the Fluid Flow: Abrupt...Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota, 1980 . 10. Petukhov, B. S., "Heat Transfer and Friction in Turbulent

Stress Intensity Solutions of Thermally Induced Cracks in Combustor Liner Hot Spots Using Finite Element Analysis (FEA)

DTIC Science & Technology

2005-12-01

EPFM elastic-plastic fracture mechanics FCG fatigue crack growth FEA finite element analysis FKN ANSYS FEA command for contact pair stiffness FTOLN...current TMF research is too general for thermal gradient applications . Moreover, the nature of a cyclically heated, localized region of higher...when separating this problem into the general engineering issues that are germane to the application , one can find much published research that is

The Shock and Vibration Bulletin. Part 1. Summaries of Presented Papers

DTIC Science & Technology

1973-10-01

Mechanical Engineering Department, University of the Negev , Israel It was recently observed [1] that during metal deformation a transient e.m.f. is...turn radiate noise. In many cases, significant contributions can be made toward solution of the overall problem by Uaing properly optimized damping...delineate the role of these resonant sources of secondary sound radiation in a USAF MAC HH-53 helicopter as regards internal cabin noise level (b

Fluid Dynamic - Structural Interactions of Labyrinth Seals.

DTIC Science & Technology

1986-08-01

A., "The Leakage of Steam Through Labyrinth Seals ", Trans. ASME, Vol. 57, 1935, pp 115-122. 21. Komotori, K., "A Consideration on the Labyrinth ...October 1980. 17. Vermes, G., "A fluid-Mechanics Approach to the Labyrinth Seal Leakage Problem", Journal of Basic Engineering, Tr. ASME, Series D...INTERACTIONS OF LABYRINTH SEALS Manuel Martinez-Sanchez John Dugundji Gas Turbine and Plasma Dynamics Laboratory D T IC Department of Aeronautics and

Air pollution from aircraft

NASA Technical Reports Server (NTRS)

Heywood, J. B.; Fay, J. A.; Chigier, N. A.

1979-01-01

A series of fundamental problems related to jet engine air pollution and combustion were examined. These include soot formation and oxidation, nitric oxide and carbon monoxide emissions mechanisms, pollutant dispension, flow and combustion characteristics of the NASA swirl can combustor, fuel atomization and fuel-air mixing processes, fuel spray drop velocity and size measurement, ignition and blowout. A summary of this work, and a bibliography of 41 theses and publications which describe this work, with abstracts, is included.

Evaluation of the Material Point Method within CTH to Model 2-Dimensional Plate Impact Problems

DTIC Science & Technology

2014-09-01

Howard University . 14. ABSTRACT The material point method (MPM) is a mixed Eulerian and Lagrangian computational method that allows for the... University in Washington, DC, as a second-year graduate student within mechanical engineering. I also attended Howard University for my undergraduate...Kevin Rugirello, Dr Andrew Tonge, Dr Jeffrey Lloyd, Dr Mary Jane Graham, and Dr Gbadebo Owolabi. vi Student Bio I am currently attending Howard

Lunar Dust Simulant in Mechanical Component Testing - Paradigm and Practicality

NASA Technical Reports Server (NTRS)

Jett, T.; Street, K.; Abel, P.; Richmond, R.

2008-01-01

Due to the uniquely harsh lunar surface environment, terrestrial test activities may not adequately represent abrasive wear by lunar dust likely to be experienced in mechanical systems used in lunar exploration. Testing to identify potential moving mechanism problems has recently begun within the NASA Engineering and Safety Center Mechanical Systems Lunar Dust Assessment activity in coordination with the Exploration Technology and Development Program Dust Management Project, and these complimentary efforts will be described. Specific concerns about differences between simulant and lunar dust, and procedures for mechanical component testing with lunar simulant will be considered. In preparing for long term operations within a dusty lunar environment, the three fundamental approaches to keeping mechanical equipment functioning are dust avoidance, dust removal, and dust tolerance, with some combination of the three likely to be found in most engineering designs. Methods to exclude dust from contact with mechanical components would constitute mitigation by dust avoidance, so testing seals for dust exclusion efficacy as a function of particle size provides useful information for mechanism design. Dust of particle size less than a micron is not well documented for impact on lunar mechanical components. Therefore, creating a standardized lunar dust simulant in the particulate size range of ca. 0.1 to 1.0 micrometer is useful for testing effects on mechanical components such as bearings, gears, seals, bushings, and other moving mechanical assemblies. Approaching actual wear testing of mechanical components, it is beneficial to first establish relative wear rates caused by dust on commonly used mechanical component materials. The wear mode due to dust within mechanical components, such as abrasion caused by dust in grease(s), needs to be considered, as well as the effects of vacuum, lunar thermal cycle, and electrostatics on wear rate.

Teaching helix and problems connected with helix using GeoGebra

NASA Astrophysics Data System (ADS)

Bímová, Daniela

2017-12-01

The contribution presents the dynamic applets created in GeoGebra that show the origin and main properties of a helix and it also presents some constructive problems connected with the helix. There are created the step by step algorithms of some constructions in the chosen applets. Three-dimensional applets include illustrative helix samples and spatial animations that help students better see problems concerning the helix spatially. There is mentioned the website in the contribution on which there is situated GeoGebra book dedicated to the topic "Helix" and containing the mentioned applets. The created applets and materials of the GeoGebra book "Helix" help in teaching and studying the course Constructive Geometry determined for the students of the Faculty of Mechanical Engineering of the Technical University of Liberec.

Some Problems of Exploitation of Jet Turbine Aircraft Engines of Lot Polish Air Lines,

DTIC Science & Technology

1977-04-26

CI ‘AD~AOII6 221 FOREIGN TECHNOLOGY DIV WR IGHT—PATTERSON AFB OHIO F/I 21/5SOME PROBLEMS OF EXPLOITATION OF JET TURBINE AIRCRAFT ENGINES O—CTC(U...EXPLOITATION OF JET TURBINE AIRCRAFT ENGINES OF LOT POLISH AIR LINE S By: Andrzej Slodownik English pages: 1~ Source: Technika Lotnicza I Astronautyczna...SOME PROBLEMS OF EXPLOITATION OF JET TURBINE AIRCRAFT ENGINES OF LOT POLISH AIR LINES Andrzej Slodownik , M. Eng . FTD— ID ( RS) I— 0 1475 — 77 I

2010 NASA Exploration Systems Mission Directorate: Lunabotics Mining Competition Systems Engineering Paper

NASA Technical Reports Server (NTRS)

2010-01-01

A fast growing approach in determining the best design concept for a problem is to hold a competition in which the rules are based on requirements similar to the actual problem. By going public with such competitions, sponsoring entities receive some of the most innovative engineering solutions in a fraction of the time and cost it would have taken to develop such concepts internally. Space exploration is a large benefactor of such design competitions as seen by the results of X-Prize Foundation and NASA lunar excavation competitions [1]. The results of NASA's past lunar excavator challenges has led to the need for an effective means of collecting lunar regolith in the absence of human beings. The 2010 Exploration Systems Mission Directorate (ESMD) Lunar Excavation Challenge was created "to engage and retain students in science, technology, engineering, and mathematics, or STEM, in a competitive environment that may result in innovative ideas and solutions, which could be applied to actual lunar excavation for NASA." [2]. The ESMD Challenge calls for "teams to use telerobotics or autonomous operations to excavate at least 10kg of lunar regolith simulant in a 15 minute time limit" [2]. The Systems Engineering approach was used in accordance with Auburn University's mechanical engineering senior design course (MECH 4240-50) to develop a telerobotic lunar excavator, seen in Fig. 1, that fulfilled requirements imposed by the NASA ESMD Competition Rules. The goal of the senior design project was to have a validated lunar excavator that would be used in the NASA ESMD lunar excavation challenge.

Engineering design: A cognitive process approach

NASA Astrophysics Data System (ADS)

Strimel, Greg Joseph

The intent of this dissertation was to identify the cognitive processes used by advanced pre-engineering students to solve complex engineering design problems. Students in technology and engineering education classrooms are often taught to use an ideal engineering design process that has been generated mostly by educators and curriculum developers. However, the review of literature showed that it is unclear as to how advanced pre-engineering students cognitively navigate solving a complex and multifaceted problem from beginning to end. Additionally, it was unclear how a student thinks and acts throughout their design process and how this affects the viability of their solution. Therefore, Research Objective 1 was to identify the fundamental cognitive processes students use to design, construct, and evaluate operational solutions to engineering design problems. Research Objective 2 was to determine identifiers within student cognitive processes for monitoring aptitude to successfully design, construct, and evaluate technological solutions. Lastly, Research Objective 3 was to create a conceptual technological and engineering problem-solving model integrating student cognitive processes for the improved development of problem-solving abilities. The methodology of this study included multiple forms of data collection. The participants were first given a survey to determine their prior experience with engineering and to provide a description of the subjects being studied. The participants were then presented an engineering design challenge to solve individually. While they completed the challenge, the participants verbalized their thoughts using an established "think aloud" method. These verbalizations were captured along with participant observational recordings using point-of-view camera technology. Additionally, the participant design journals, design artifacts, solution effectiveness data, and teacher evaluations were collected for analysis to help achieve the research objectives of this study. Two independent coders then coded the video/audio recordings and the additional design data using Halfin's (1973) 17 mental processes for technological problem-solving. The results of this study indicated that the participants employed a wide array of mental processes when solving engineering design challenges. However, the findings provide a general analysis of the number of times participants employed each mental process, as well as the amount of time consumed employing the various mental processes through the different stages of the engineering design process. The results indicated many similarities between the students solving the problem, which may highlight voids in current technology and engineering education curricula. Additionally, the findings showed differences between the processes employed by participants that created the most successful solutions and the participants who developed the least effective solutions. Upon comparing and contrasting these processes, recommendations for instructional strategies to enhance a student's capability for solving engineering design problems were developed. The results also indicated that students, when left without teacher intervention, use a simplified and more natural process to solve design challenges than the 12-step engineering design process reported in much of the literature. Lastly, these data indicated that students followed two different approaches to solving the design problem. Some students employed a sequential and logical approach, while others employed a nebulous, solution centered trial-and-error approach to solving the problem. In this study the participants who were more sequential had better performing solutions. Examining these two approaches and the student cognition data enabled the researcher to generate a conceptual engineering design model for the improved teaching and development of engineering design problem solving.

The knee meniscus: structure-function, pathophysiology, current repair techniques, and prospects for regeneration

PubMed Central

Makris, Eleftherios A.; Hadidi, Pasha; Athanasiou, Kyriacos A.

2011-01-01

Extensive scientific investigations in recent decades have established the anatomical, biomechanical, and functional importance that the meniscus holds within the knee joint. As a vital part of the joint, it acts to prevent the deterioration and degeneration of articular cartilage, and the onset and development of osteoarthritis. For this reason, research into meniscus repair has been the recipient of particular interest from the orthopedic and bioengineering communities. Current repair techniques are only effective in treating lesions located in the peripheral vascularized region of the meniscus. Healing lesions found in the inner avascular region, which functions under a highly demanding mechanical environment, is considered to be a significant challenge. An adequate treatment approach has yet to be established, though many attempts have been undertaken. The current primary method for treatment is partial meniscectomy, which commonly results in the progressive development of osteoarthritis. This drawback has shifted research interest towards the fields of biomaterials and bioengineering, where it is hoped that meniscal deterioration can be tackled with the help of tissue engineering. So far, different approaches and strategies have contributed to the in vitro generation of meniscus constructs, which are capable of restoring meniscal lesions to some extent, both functionally as well as anatomically. The selection of the appropriate cell source (autologous, allogeneic, or xenogeneic cells, or stem cells) is undoubtedly regarded as key to successful meniscal tissue engineering. Furthermore, a large variation of scaffolds for tissue engineering have been proposed and produced in experimental and clinical studies, although a few problems with these (e.g., byproducts of degradation, stress shielding) have shifted research interest towards new strategies (e.g., scaffoldless approaches, self-assembly). A large number of different chemical (e.g., TGF-β1, C-ABC) and mechanical stimuli (e.g., direct compression, hydrostatic pressure) have also been investigated, both in terms of encouraging functional tissue formation, as well as in differentiating stem cells. Even though the problems accompanying meniscus tissue engineering research are considerable, we are undoubtedly in the dawn of a new era, whereby recent advances in biology, engineering, and medicine are leading to the successful treatment of meniscal lesions. PMID:21764438

Recognition vs Reverse Engineering in Boolean Concepts Learning

ERIC Educational Resources Information Center

Shafat, Gabriel; Levin, Ilya

2012-01-01

This paper deals with two types of logical problems--recognition problems and reverse engineering problems, and with the interrelations between these types of problems. The recognition problems are modeled in the form of a visual representation of various objects in a common pattern, with a composition of represented objects in the pattern.…

The Implementation and Evaluation of a Project-Oriented Problem-Based Learning Module in a First Year Engineering Programme

ERIC Educational Resources Information Center

McLoone, Seamus C.; Lawlor, Bob J.; Meehan, Andrew R.

2016-01-01

This paper describes how a circuits-based project-oriented problem-based learning educational model was integrated into the first year of a Bachelor of Engineering in Electronic Engineering programme at Maynooth University, Ireland. While many variations of problem based learning exist, the presented model is closely aligned with the model used in…

The Technology of Forming of Innovative Content for Engineering Education

ERIC Educational Resources Information Center

Kayumova, Lilija A.; Savva, Lubov I.; Soldatchenko, Aleksandr L.; Sirazetdinov, Rustem M.; Akhmetov, Linar G.

2016-01-01

The relevance of the study is conditioned by the modernization of engineering education aimed at specialists' training to solve engineering and economic problems effectively. The goal of the paper is to develop the technology of the innovative content's formation for engineering education. The leading method to the study of this problem is a…

Engineering education in the wake of hurricane Katrina

PubMed Central

Lima, Marybeth

2007-01-01

Living through hurricane Katrina and its aftermath and reflecting on these experiences from technical and non-technical standpoints has led me to reconsider my thoughts and philosophy on engineering education. I present three ideas regarding engineering education pedagogy that I believe will prepare future engineers for problem-solving in an increasingly complex world. They are (1) we must practice radical (to the root) engineering, (2) we must illustrate connections between engineering and public policy, and (3) we will join the charge to find sustainable solutions to problems. Ideas for bringing each of these concepts into engineering curricula through methods such as case study, practicing broad information gathering and data interpretation, and other methods inside and outside the classroom, are discussed. I believe that the consequences of not considering the root issues of problems to be solved, and of not including policy and sustainability considerations when problems to be solved are framed will lead our profession toward well meaning but insufficient utility. Hurricane Katrina convinced me that we must do better as educators to prepare our students for engineering for a sustainable world. PMID:18271988

Simulating nonlinear neutrino flavor evolution

NASA Astrophysics Data System (ADS)

Duan, H.; Fuller, G. M.; Carlson, J.

2008-10-01

We discuss a new kind of astrophysical transport problem: the coherent evolution of neutrino flavor in core collapse supernovae. Solution of this problem requires a numerical approach which can simulate accurately the quantum mechanical coupling of intersecting neutrino trajectories and the associated nonlinearity which characterizes neutrino flavor conversion. We describe here the two codes developed to attack this problem. We also describe the surprising phenomena revealed by these numerical calculations. Chief among these is that the nonlinearities in the problem can engineer neutrino flavor transformation which is dramatically different to that in standard Mikheyev Smirnov Wolfenstein treatments. This happens even though the neutrino mass-squared differences are measured to be small, and even when neutrino self-coupling is sub-dominant. Our numerical work has revealed potential signatures which, if detected in the neutrino burst from a Galactic core collapse event, could reveal heretofore unmeasurable properties of the neutrinos, such as the mass hierarchy and vacuum mixing angle θ13.

Teaching ethics to engineers: ethical decision making parallels the engineering design process.

PubMed

Bero, Bridget; Kuhlman, Alana

2011-09-01

In order to fulfill ABET requirements, Northern Arizona University's Civil and Environmental engineering programs incorporate professional ethics in several of its engineering courses. This paper discusses an ethics module in a 3rd year engineering design course that focuses on the design process and technical writing. Engineering students early in their student careers generally possess good black/white critical thinking skills on technical issues. Engineering design is the first time students are exposed to "grey" or multiple possible solution technical problems. To identify and solve these problems, the engineering design process is used. Ethical problems are also "grey" problems and present similar challenges to students. Students need a practical tool for solving these ethical problems. The step-wise engineering design process was used as a model to demonstrate a similar process for ethical situations. The ethical decision making process of Martin and Schinzinger was adapted for parallelism to the design process and presented to students as a step-wise technique for identification of the pertinent ethical issues, relevant moral theories, possible outcomes and a final decision. Students had greatest difficulty identifying the broader, global issues presented in an ethical situation, but by the end of the module, were better able to not only identify the broader issues, but also to more comprehensively assess specific issues, generate solutions and a desired response to the issue.

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…

An inquiry-based approach to the Franck-Hertz experiment

NASA Astrophysics Data System (ADS)

Persano Adorno, Dominique; Pizzolato, Nicola

2016-05-01

The practice of scientists and engineers is today exerted within interdisciplinary contexts, placed at the intersections of different research fields, including nanoscale science. The development of the required competences is based on an effective science and engineering instruction, which should be able to drive the students towards a deeper understanding of quantum mechanics fundamental concepts and, at the same time, strengthen their reasoning skills and transversal abilities. In this study we report the results of an inquiry-driven learning path experienced by a sample of 12 electronic engineering undergraduates engaged to perform the Franck-Hertz experiment. Before being involved in this experimental activity, the students received a traditional lecture-based instruction on the fundamental concepts of quantum mechanics, but their answers to an open-ended questionnaire, administered at the beginning of the inquiry activity, demonstrated that the acquired knowledge was characterized by a strictly theoretical vision of quantum science, basically in terms of an artificial mathematical framework having very poor connections with the real world. The Franck Hertz experiment was introduced to the students by starting from the problem of finding an experimental confirmation of the Bohr's postulates asserting that atoms can absorb energy only in quantum portions. The whole activity has been videotaped and this allowed us to deeply analyse the student perception's change about the main concepts of quantum mechanics. We have found that the active participation to this learning experience favored the building of cognitive links among student theoretical perceptions of quantum mechanics and their vision of quantum phenomena, within an everyday context of knowledge. Furthermore, our findings confirm the benefits of integrating traditional lecture-based instruction on quantum mechanics with learning experiences driven by inquiry-based teaching strategies.

Engineering of Impulse Mechanism for Mechanical Hander Power Tools

NASA Astrophysics Data System (ADS)

Nikolaevich Drozdov, Anatoliy

2018-03-01

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

Mechanical Engineering Senior Design Project Final Presentations | College

Science.gov Websites

Mechanical Engineering Senior Design Project Final Presentations December 7, 2015 Mechanical Engineering On Wednesday, Dec. 9th, the mechanical engineering senior design project final presentations will be made in and Steven Keller Objective: Design a temperature controlled unit that would cool and maintain a

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

Coupled transverse and torsional vibrations in a mechanical system with two identical beams

NASA Astrophysics Data System (ADS)

Vlase, S.; Marin, M.; Scutaru, M. L.; Munteanu, R.

2017-06-01

The paper aims to study a plane system with bars, with certain symmetries. Such problems can be encountered frequently in industry and civil engineering. Considerations related to the economy of the design process, constructive simplicity, cost and logistics make the use of identical parts a frequent procedure. The paper aims to determine the properties of the eigenvalues and eigenmodes for transverse and torsional vibrations of a mechanical system where two of the three component bars are identical. The determination of these properties allows the calculus effort and the computation time and thus increases the accuracy of the results in such matters.

Wet granular materials

NASA Astrophysics Data System (ADS)

Mitarai, Namiko; Nori, Franco

2006-04-01

Most studies on granular physics have focused on dry granular media, with no liquids between the grains. However, in geology and many real world applications (e.g. food processing, pharmaceuticals, ceramics, civil engineering, construction, and many industrial applications), liquid is present between the grains. This produces inter-grain cohesion and drastically modifies the mechanical properties of the granular media (e.g. the surface angle can be larger than 90 degrees). Here we present a review of the mechanical properties of wet granular media, with particular emphasis on the effect of cohesion. We also list several open problems that might motivate future studies in this exciting but mostly unexplored field.

An Elementary Introduction to Recently Developed Computational Methods for Solving Singularly Perturbed Partial Differential Equations Arising in Science and Engineering

NASA Astrophysics Data System (ADS)

Kumar, Manoj; Srivastava, Akanksha

2013-01-01

This paper presents a survey of innovative approaches of the most effective computational techniques for solving singular perturbed partial differential equations, which are useful because of their numerical and computer realizations. Many applied problems appearing in semiconductors theory, biochemistry, kinetics, theory of electrical chains, economics, solid mechanics, fluid dynamics, quantum mechanics, and many others can be modelled as singularly perturbed systems. Here, we summarize a wide range of research articles published by numerous researchers during the last ten years to get a better view of the present scenario in this area of research.

Quantifying Cyber-Resilience Against Resource-Exhaustion Attacks

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

Fink, Glenn A.; Griswold, Richard L.; Beech, Zachary W.

2014-07-11

Resilience in the information sciences is notoriously difficult to define much less to measure. But in mechanical engi- neering, the resilience of a substance is mathematically defined as the area under the stress vs. strain curve. We took inspiration from mechanics in an attempt to define resilience precisely for information systems. We first examine the meaning of resilience in language and engineering terms and then translate these definitions to information sciences. Then we tested our definitions of resilience for a very simple problem in networked queuing systems. We discuss lessons learned and make recommendations for using this approach in futuremore » work.« less

Revision of certification standards for aviation maintenance personnel

NASA Technical Reports Server (NTRS)

Vipond, Leslie K.

1992-01-01

Part 65, Subparts D and E, of the Federal Aviation Regulations (FAR) identify the certification requirements for aviation mechanics and aviation repairmen. The training, experience, privileges, ratings, recordkeeping, and currency requirements for aviation maintenance personnel are also addressed by those parts of the FAR. The recent emergence of the aging fleet problem and the introduction of new technologies, aircraft, engines, and aeronautical products has caused certain portions of these rules to become obsolete. Further, international political arrangements, such as bilateral airworthiness and maintenance agreements, International Civil Aviation Organization (ICAO) standards, certain international agreements for maintenance personnel training, and mechanic certificate reciprocity, have all impacted on the current regulatory policy.

SAFSIM theory manual: A computer program for the engineering simulation of flow systems

NASA Astrophysics Data System (ADS)

Dobranich, Dean

1993-12-01

SAFSIM (System Analysis Flow SIMulator) is a FORTRAN computer program for simulating the integrated performance of complex flow systems. SAFSIM provides sufficient versatility to allow the engineering simulation of almost any system, from a backyard sprinkler system to a clustered nuclear reactor propulsion system. In addition to versatility, speed and robustness are primary SAFSIM development goals. SAFSIM contains three basic physics modules: (1) a fluid mechanics module with flow network capability; (2) a structure heat transfer module with multiple convection and radiation exchange surface capability; and (3) a point reactor dynamics module with reactivity feedback and decay heat capability. Any or all of the physics modules can be implemented, as the problem dictates. SAFSIM can be used for compressible and incompressible, single-phase, multicomponent flow systems. Both the fluid mechanics and structure heat transfer modules employ a one-dimensional finite element modeling approach. This document contains a description of the theory incorporated in SAFSIM, including the governing equations, the numerical methods, and the overall system solution strategies.

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.

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...

LDRD Final Report: Global Optimization for Engineering Science Problems

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

HART,WILLIAM E.

1999-12-01

For a wide variety of scientific and engineering problems the desired solution corresponds to an optimal set of objective function parameters, where the objective function measures a solution's quality. The main goal of the LDRD ''Global Optimization for Engineering Science Problems'' was the development of new robust and efficient optimization algorithms that can be used to find globally optimal solutions to complex optimization problems. This SAND report summarizes the technical accomplishments of this LDRD, discusses lessons learned and describes open research issues.

Engineering applications of metaheuristics: an introduction

NASA Astrophysics Data System (ADS)

Oliva, Diego; Hinojosa, Salvador; Demeshko, M. V.

2017-01-01

Metaheuristic algorithms are important tools that in recent years have been used extensively in several fields. In engineering, there is a big amount of problems that can be solved from an optimization point of view. This paper is an introduction of how metaheuristics can be used to solve complex problems of engineering. Their use produces accurate results in problems that are computationally expensive. Experimental results support the performance obtained by the selected algorithms in such specific problems as digital filter design, image processing and solar cells design.

Mechanical properties of lunar regolith and lunar soil simulant

NASA Technical Reports Server (NTRS)

Perkins, Steven W.

1989-01-01

Through the Surveyor 3 and 7, and Apollo 11-17 missions a knowledge of the mechanical properties of Lunar regolith were gained. These properties, including material cohesion, friction, in-situ density, grain-size distribution and shape, and porosity, were determined by indirect means of trenching, penetration, and vane shear testing. Several of these properties were shown to be significantly different from those of terrestrial soils, such as an interlocking cohesion and tensile strength formed in the absence of moisture and particle cementation. To characterize the strength and deformation properties of Lunar regolith experiments have been conducted on a lunar soil simulant at various initial densities, fabric arrangements, and composition. These experiments included conventional triaxial compression and extension, direct tension, and combined tension-shear. Experiments have been conducted at low levels of effective confining stress. External conditions such as membrane induced confining stresses, end platten friction and material self weight have been shown to have a dramatic effect on the strength properties at low levels of confining stress. The solution has been to treat these external conditions and the specimen as a full-fledged boundary value problem rather than the idealized elemental cube of mechanics. Centrifuge modeling allows for the study of Lunar soil-structure interaction problems. In recent years centrifuge modeling has become an important tool for modeling processes that are dominated by gravity and for verifying analysis procedures and studying deformation and failure modes. Centrifuge modeling is well established for terrestrial enginering and applies equally as well to Lunar engineering. A brief review of the experiments is presented in graphic and outline form.

Thermomechanical Properties of Polylactic Acid-Graphene Composites: A State-of-the-Art Review for Biomedical Applications

PubMed Central

2017-01-01

Due to its biodegradable and bioabsorbable characteristics polylactic acid (PLA) has attracted considerable attention for numerous biomedical applications. Moreover, a number of tissue engineering problems for function restoration of impaired tissues have been addressed by using PLA and its copolymers due to their biocompatibility and distinctive mechanical properties. Recent studies on various stereocomplex formation between enantiomeric PLA, poly(l-lactide) (PLLA) and poly(d-lactide) (PDLA) indicated that stereocomplexation enhances the mechanical properties as well as the thermal- and hydrolysis-resistance of PLA polymers. On the other hand, biomedical application of graphene is a relatively new front with significant potential. Many recent reports have indicated that understanding of graphene-cell (or tissue, organ) interactions; particularly the cellular uptake mechanisms are still challenging. Therefore, use of graphene or graphene oxide properly embedded in suitable PLA matrices can positively impact and accelerate the growth, differentiation, and proliferation of stem cells, conceivably minimizing concerns over cytotoxicity of graphene. As such, PLA-graphene composites hold great promise in tissue engineering, regenerative medicine, and in other biomedical fields. However, since PLA is classified as a hard bio-polyester prone to hydrolysis, understanding and engineering of thermo-mechanical properties of PLA-graphene composites are very crucial for such cutting-edge applications. Hence, this review aims to present an overview of current advances in the preparation and applications of PLA-graphene composites and their properties with focus on various biomedical uses such as scaffolds, drug delivery, cancer therapy, and biological imaging, together with a brief discussion on the challenges and perspectives for future research in this field. PMID:28773109

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.

[Construction of automatic elucidation platform for mechanism of traditional Chinese medicine].

PubMed

Zhang, Bai-xia; Luo, Si-jun; Yan, Jing; Gu, Hao; Luo, Ji; Zhang, Yan-ling; Tao, Ou; Wang, Yun

2015-10-01

Aim at the two problems in the field of traditional Chinese medicine (TCM) mechanism elucidation, one is the lack of detailed biological processes information, next is the low efficient in constructing network models, we constructed an auxiliary elucidation system for the TCM mechanism and realize the automatic establishment of biological network model. This study used the Entity Grammar Systems (EGS) as the theoretical framework, integrated the data of formulae, herbs, chemical components, targets of component, biological reactions, signaling pathways and disease related proteins, established the formal models, wrote the reasoning engine, constructed the auxiliary elucidation system for the TCM mechanism elucidation. The platform provides an automatic modeling method for biological network model of TCM mechanism. It would be benefit to perform the in-depth research on TCM theory of natures and combination and provides the scientific references for R&D of TCM.

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.

Vertical stream curricula integration of problem-based learning using an autonomous vacuum robot in a mechatronics course

NASA Astrophysics Data System (ADS)

Chin, Cheng; Yue, Keng

2011-10-01

Difficulties in teaching a multi-disciplinary subject such as the mechatronics system design module in Departments of Mechatronics Engineering at Temasek Polytechnic arise from the gap in experience and skill among staff and students who have different backgrounds in mechanical, computer and electrical engineering within the Mechatronics Department. The departments piloted a new vertical stream curricula model (VSCAM) to enhance student learning in mechatronics system design through integration of educational activities from the first to the second year of the course. In this case study, a problem-based learning (PBL) method on an autonomous vacuum robot in the mechatronics systems design module was proposed to allow the students to have hands-on experience in the mechatronics system design. The proposed works included in PBL consist of seminar sessions, weekly works and project presentation to provide holistic assessment on teamwork and individual contributions. At the end of VSCAM, an integrative evaluation was conducted using confidence logs, attitude surveys and questionnaires. It was found that the activities were quite appreciated by the participating staff and students. Hence, PBL has served as an effective pedagogical framework for teaching multidisciplinary subjects in mechatronics engineering education if adequate guidance and support are given to staff and students.

High-Performance Parallel Analysis of Coupled Problems for Aircraft Propulsion

NASA Technical Reports Server (NTRS)

Felippa, C. A.; Farhat, C.; Park, K. C.; Gumaste, U.; Chen, P.-S.; Lesoinne, M.; Stern, P.

1997-01-01

Applications are described of high-performance computing methods to the numerical simulation of complete jet engines. The methodology focuses on the partitioned analysis of the interaction of the gas flow with a flexible structure and with the fluid mesh motion driven by structural displacements. The latter is treated by a ALE technique that models the fluid mesh motion as that of a fictitious mechanical network laid along the edges of near-field elements. New partitioned analysis procedures to treat this coupled three-component problem were developed. These procedures involved delayed corrections and subcycling, and have been successfully tested on several massively parallel computers, including the iPSC-860, Paragon XP/S and the IBM SP2. The NASA-sponsored ENG10 program was used for the global steady state analysis of the whole engine. This program uses a regular FV-multiblock-grid discretization in conjunction with circumferential averaging to include effects of blade forces, loss, combustor heat addition, blockage, bleeds and convective mixing. A load-balancing preprocessor for parallel versions of ENG10 was developed as well as the capability for the first full 3D aeroelastic simulation of a multirow engine stage. This capability was tested on the IBM SP2 parallel supercomputer at NASA Ames.

Developing Creativity and Problem-Solving Skills of Engineering Students: A Comparison of Web- and Pen-and-Paper-Based Approaches

ERIC Educational Resources Information Center

Valentine, Andrew; Belski, Iouri; Hamilton, Margaret

2017-01-01

Problem-solving is a key engineering skill, yet is an area in which engineering graduates underperform. This paper investigates the potential of using web-based tools to teach students problem-solving techniques without the need to make use of class time. An idea generation experiment involving 90 students was designed. Students were surveyed…

Integrating Cost Engineering and Project Management in a Junior Engineering Economics Course and a Senior Capstone Project Design Course

ERIC Educational Resources Information Center

Tickles, Virginia C.; Li, Yadong; Walters, Wilbur L.

2013-01-01

Much criticism exists concerning a lack of focus on real-world problem-solving in the science, technology, engineering and mathematics (STEM) infrastructures. Many of these critics say that current educational infrastructures are incapable in preparing future scientists and engineers to solve the complex and multidisciplinary problems this society…

A Case Study: Problem-Based Learning for Civil Engineering Students in Transportation Courses

ERIC Educational Resources Information Center

Ahern, A. A.

2010-01-01

This paper describes two case studies where problem-based learning (PBL) has been introduced to undergraduate civil engineering students in University College Dublin. PBL has recently been put in place in the penultimate and final year transport engineering classes in the civil engineering degree in University College Dublin. In this case study,…

Using Ontological Engineering to Overcome AI-ED Problems: Contribution, Impact and Perspectives

ERIC Educational Resources Information Center

Mizoguchi, Riichiro; Bourdeau, Jacqueline

2016-01-01

This article reflects on the ontology engineering methodology discussed by the paper entitled "Using Ontological Engineering to Overcome AI-ED Problems" published in this journal in 2000. We discuss the achievements obtained in the last 10 years, the impact of our work as well as recent trends and perspectives in ontology engineering for…

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.

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)

Sediment problems in urban areas

USGS Publications Warehouse

Guy, Harold P.

1970-01-01

One obstacle to a scientific recognition and an engineering solution to sediment-related environmental problems is that such problems are bound in conflicting and generally undefinable political and institutional restraints. Also, some of the difficulty may involve the fact that the scientist or engineer, because of his relatively narrow field of investigation, cannot always completely envision the less desirable effects of his work and communicate alternative solutions to the public. For example, the highway and motor-vehicle engineers have learned how to provide the means by which one can transport himself from one point to another with such great efficiency that a person's employment in this country is now commonly more than 5 miles from his residence. However, providing such efficient personal transport has created numerous serious environmental problems. Obstacles to recognition of and action to control sediment problems in and around urban areas are akin to other environmental problems with respect to the many scientific, engineering, economic, and social aspects.

Preparation of decellularized vascular matrix by co-crosslinking of procyanidins and glutaraldehyde.

PubMed

Wang, Xiaotong; Ma, Bing; Chang, Jiang

2015-01-01

Vascular extracellular matrices (vECMs) have shown potential for small-diameter blood vessel tissue engineering applications. However, problems such as chemical instability and easy calcification are still remained. Chemical crosslinking using crosslinkers such as glutaraldehyde (GA) can improve mechanical properties and proteolysis resistance of vECMs, but leads to calcification and cytotoxicity. Procyanidins (PC) can crosslink ECMs with anti-calcification property and cytocompatibility, but the mechanical properties and chemical stability are unsatisfactory. A novel co-crosslinking technique using PC and GA was developed, which combines the advantages of both PC and GA for enhancing mechanical properties and stability of vECMs with reduced calcification and cytotoxicity. Fresh carotid were decellularized and then crosslinked by PC and subsequent GA for 6 h respectively. The mechanical properties, dynamic release of PC, enzymatic degradation, calcification and cytotoxicity of crosslinked samples were evaluated. The co-crosslinked vECMs showed enhanced tensile strength, chemical and biological stability, comparable anti-calcification property as compared to pure PC-crosslinked samples. Cytotoxicity assay showed that the co-crosslinked vECMs were cytocompatible for supporting the adhesion and proliferation of HUVECs. Co-crosslinking with PC and GA might be a useful method for preparation of vECM scaffolds with potential applications in small-diameter blood vessel tissue engineering.

Selected topics of fluid mechanics

USGS Publications Warehouse

Kindsvater, Carl E.

1958-01-01

The fundamental equations of fluid mechanics are specific expressions of the principles of motion which are ascribed to Isaac Newton. Thus, the equations which form the framework of applied fluid mechanics or hydraulics are, in addition to the equation of continuity, the Newtonian equations of energy and momentum. These basic relationships are also the foundations of river hydraulics. The fundamental equations are developed in this report with sufficient rigor to support critical examinations of their applicability to most problems met by hydraulic engineers of the Water Resources Division of the United States Geological Survey. Physical concepts are emphasized, and mathematical procedures are the simplest consistent with the specific requirements of the derivations. In lieu of numerical examples, analogies, and alternative procedures, this treatment stresses a brief methodical exposition of the essential principles. An important objective of this report is to prepare the user to read the literature of the science. Thus, it begins With a basic vocabulary of technical symbols, terms, and concepts. Throughout, emphasis is placed on the language of modern fluid mechanics as it pertains to hydraulic engineering. The basic differential and integral equations of simple fluid motion are derived, and these equations are, in turn, used to describe the essential characteristics of hydrostatics and piezometry. The one-dimensional equations of continuity and motion are defined and are used to derive the general discharge equation. The flow net is described as a means of demonstrating significant characteristics of two-dimensional irrotational flow patterns. A typical flow net is examined in detail. The influence of fluid viscosity is described as an obstacle to the derivation of general, integral equations of motion. It is observed that the part played by viscosity is one which is usually dependent on experimental evaluation. It follows that the dimensionless ratios known as the Euler, Froude, Reynolds, Weber, and Cauchy numbers are defined as essential tools for interpreting and using experimental data. The derivations of the energy and momentum equations are treated in detail. One-dimensional equations for steady nonuniform flow are developed, and the restrictions applicable to the equations are emphasized. Conditions of uniform and gradually varied flow are discussed, and the origin of the Chezy equation is examined in relation to both the energy and the momentum equations. The inadequacy of all uniform-flow equations as a means of describing gradually varied flow is explained. Thus, one of the definitive problems of river hydraulics is analyzed in the light of present knowledge. This report is the outgrowth of a series of short schools conducted during the spring and summer of 1953 for engineers of the Surface Water Branch, Water Resources Division, U. S. Geological Survey. The topics considered are essentially the same as the topics selected for inclusion in the schools. However, in order that they might serve better as a guide and outline for informal study, the arrangement of the writer's original lecture notes has been considerably altered. The purpose of the report, like the purpose of the schools which inspired it, is to build a simple but strong framework of the fundamentals of fluid mechanics. It is believed that this framework is capable of supporting a detailed analysis of most of the practical problems met by the engineers of the Geological Survey. It is hoped that the least accomplishment of this work will be to inspire the reader with the confidence and desire to read more of the recent and current technical literature of modern fluid mechanics.

Material engineering and fabrication experiences

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

Havn, T.

1995-10-01

Material selection for hydrocarbon and sea water systems is shortly described and experiences are explained. The risk of external stress corrosion cracking is discussed. Same is the need for isolation pipe spools to avoid galvanic corrosion. Possible corrosion as result of hot work reduction on platform modification work is discussed. Benefit from positive material identification is explained and the solution of a weld problem due to mix-up of filler material is shown. Experiences with cold bending and subsea material engineering are discussed and recommendations are given. Fracture mechanic techniques with purpose of avoiding costly replacement and repair welding are shownmore » by two examples. At the end the new cost reduction trend of using performance based specifications is shortly discussed with respect to material requirements.« less

A Tissue Engineered Model of Aging: Interdependence and Cooperative Effects in Failing Tissues.

PubMed

Acun, A; Vural, D C; Zorlutuna, P

2017-07-11

Aging remains a fundamental open problem in modern biology. Although there exist a number of theories on aging on the cellular scale, nearly nothing is known about how microscopic failures cascade to macroscopic failures of tissues, organs and ultimately the organism. The goal of this work is to bridge microscopic cell failure to macroscopic manifestations of aging. We use tissue engineered constructs to control the cellular-level damage and cell-cell distance in individual tissues to establish the role of complex interdependence and interactions between cells in aging tissues. We found that while microscopic mechanisms drive aging, the interdependency between cells plays a major role in tissue death, providing evidence on how cellular aging is connected to its higher systemic consequences.

Engineering aspects of the application of structural materials in the 5 MW-ESS-mercury-target

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

Guttek, B.

1996-06-01

A main problem of the ESS-Hg-target development and the design of the components of its primary Hg-circuit is the choice of structural materials. As designing, calculations and experiments with elected materials take time and are very costy, a preview on their successful application has to be done before as detailed as possible. One aspect on this is to have the knowledge of characteristics values of the structural material candidates under the occuring mechanical and thermal loads, irradiation, corrosion and erosion. Another point is the technology of engineering concerning the manufacturing, welding, surface treatment, and quality control of such parts andmore » components under the demand to reach maximum lifetime.« less

Timoshenko beam model for chiral materials

NASA Astrophysics Data System (ADS)

Ma, T. Y.; Wang, Y. N.; Yuan, L.; Wang, J. S.; Qin, Q. H.

2017-12-01

Natural and artificial chiral materials such as deoxyribonucleic acid (DNA), chromatin fibers, flagellar filaments, chiral nanotubes, and chiral lattice materials widely exist. Due to the chirality of intricately helical or twisted microstructures, such materials hold great promise for use in diverse applications in smart sensors and actuators, force probes in biomedical engineering, structural elements for absorption of microwaves and elastic waves, etc. In this paper, a Timoshenko beam model for chiral materials is developed based on noncentrosymmetric micropolar elasticity theory. The governing equations and boundary conditions for a chiral beam problem are derived using the variational method and Hamilton's principle. The static bending and free vibration problem of a chiral beam are investigated using the proposed model. It is found that chirality can significantly affect the mechanical behavior of beams, making materials more flexible compared with nonchiral counterparts, inducing coupled twisting deformation, relatively larger deflection, and lower natural frequency. This study is helpful not only for understanding the mechanical behavior of chiral materials such as DNA and chromatin fibers and characterizing their mechanical properties, but also for the design of hierarchically structured chiral materials.

Timoshenko beam model for chiral materials

NASA Astrophysics Data System (ADS)

Ma, T. Y.; Wang, Y. N.; Yuan, L.; Wang, J. S.; Qin, Q. H.

2018-06-01

Natural and artificial chiral materials such as deoxyribonucleic acid (DNA), chromatin fibers, flagellar filaments, chiral nanotubes, and chiral lattice materials widely exist. Due to the chirality of intricately helical or twisted microstructures, such materials hold great promise for use in diverse applications in smart sensors and actuators, force probes in biomedical engineering, structural elements for absorption of microwaves and elastic waves, etc. In this paper, a Timoshenko beam model for chiral materials is developed based on noncentrosymmetric micropolar elasticity theory. The governing equations and boundary conditions for a chiral beam problem are derived using the variational method and Hamilton's principle. The static bending and free vibration problem of a chiral beam are investigated using the proposed model. It is found that chirality can significantly affect the mechanical behavior of beams, making materials more flexible compared with nonchiral counterparts, inducing coupled twisting deformation, relatively larger deflection, and lower natural frequency. This study is helpful not only for understanding the mechanical behavior of chiral materials such as DNA and chromatin fibers and characterizing their mechanical properties, but also for the design of hierarchically structured chiral materials.

Lightning safety of animals.

PubMed

Gomes, Chandima

2012-11-01

This paper addresses a concurrent multidisciplinary problem: animal safety against lightning hazards. In regions where lightning is prevalent, either seasonally or throughout the year, a considerable number of wild, captive and tame animals are injured due to lightning generated effects. The paper discusses all possible injury mechanisms, focusing mainly on animals with commercial value. A large number of cases from several countries have been analyzed. Economically and practically viable engineering solutions are proposed to address the issues related to the lightning threats discussed.

Fatigue crack growth model RANDOM2 user manual. Appendix 1: Development of advanced methodologies for probabilistic constitutive relationships of material strength models

NASA Technical Reports Server (NTRS)

Boyce, Lola; Lovelace, Thomas B.

1989-01-01

FORTRAN program RANDOM2 is presented in the form of a user's manual. RANDOM2 is based on fracture mechanics using a probabilistic fatigue crack growth model. It predicts the random lifetime of an engine component to reach a given crack size. Details of the theoretical background, input data instructions, and a sample problem illustrating the use of the program are included.

General linear methods and friends: Toward efficient solutions of multiphysics problems

NASA Astrophysics Data System (ADS)

Sandu, Adrian

2017-07-01

Time dependent multiphysics partial differential equations are of great practical importance as they model diverse phenomena that appear in mechanical and chemical engineering, aeronautics, astrophysics, meteorology and oceanography, financial modeling, environmental sciences, etc. There is no single best time discretization for the complex multiphysics systems of practical interest. We discuss "multimethod" approaches that combine different time steps and discretizations using the rigourous frameworks provided by Partitioned General Linear Methods and Generalize-structure Additive Runge Kutta Methods..

[Plant genetic engineering in Monsanto company: from the first laboratory experiments to worldwide practical use].

PubMed

Konov, A L; Velchev, M; Parcel, D

2005-01-01

The history of modern biotechnology of agricultural plants is briefly considered in the article. Methods of genetic transformation and regeneration of transgenic plants as well as the mechanisms of resistance of genetically modified plants to herbicides and pests are discussed. By the example of genetically modified varieties and hybrids there are shown the ways of solving the problem of weeds and pests. The questions of biosafety legislation in different countries are considered.

Mechanics of the Panama Canal slides

USGS Publications Warehouse

Becker, George F.

1917-01-01

Dr. Becker visited the Canal Zone in 1913 as a geologist of the United States Geological Survey and since that time has given the problem the benefit of his study. His appointment as a member of the committee of the National Academy of Sciences has made it appropriate for his conclusions, based upon his personal observations and already reported in part to the Canal Commission, to be stated for the benefit of his associates and other American scientists and engineers.

Mechanical Chevrons and Fluidics for Advanced Military Aircraft Noise Reduction

DTIC Science & Technology

2011-03-01

at or near the nozzle lip. Therefore, for the problem at hand, the simulations will need to accurately capture shock waves , unsteady large-scale...simulations could accurately capture the flow field and near-field noise from representative jet engine nozzles and indeed this was a go/no-go...mixing noise. The first two types of noise are related to the shock waves that are present in the high-speed jet flow. While the mixing noise

Increasing the reliability of labor of railroad engineers

NASA Technical Reports Server (NTRS)

Genes, V. S.; Madiyevskiy, Y. M.

1975-01-01

It has been shown that the group of problems related to temporary overloads still require serious development with respect to further automating the basic control operation - programmed selection of speed and braking. The problem of systems for warning the engineer about the condition of the unseen track segments remains a very serious one. Systems of hygenic support of the engineer also require constructive development. The problems of ensuring the reliability of work of engineers in periods of low information load, requiring motor acts, can basically be considered theoretically solved.

Investigation of finite element: ABC methods for electromagnetic field simulation. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Chatterjee, A.; Volakis, John L.; Nguyen, J.

1994-01-01

The mechanics of wave propagation in the presence of obstacles is of great interest in many branches of engineering and applied mathematics like electromagnetics, fluid dynamics, geophysics, seismology, etc. Such problems can be broadly classified into two categories: the bounded domain or the closed problem and the unbounded domain or the open problem. Analytical techniques have been derived for the simpler problems; however, the need to model complicated geometrical features, complex material coatings and fillings, and to adapt the model to changing design parameters have inevitably tilted the balance in favor of numerical techniques. The modeling of closed problems presents difficulties primarily in proper meshing of the interior region. However, problems in unbounded domains pose a unique challenge to computation, since the exterior region is inappropriate for direct implementation of numerical techniques. A large number of solutions have been proposed but only a few have stood the test of time and experiment. The goal of this thesis is to develop an efficient and reliable partial differential equation technique to model large three dimensional scattering problems in electromagnetics.

Engineering with uncertainty: monitoring air bag performance.

PubMed

Wetmore, Jameson M

2008-06-01

Modern engineering is complicated by an enormous number of uncertainties. Engineers know a great deal about the material world and how it works. But due to the inherent limits of testing and the complexities of the world outside the lab, engineers will never be able to fully predict how their creations will behave. One way the uncertainties of engineering can be dealt with is by actively monitoring technologies once they have left the development and production stage. This article uses an episode in the history of automobile air bags as an example of engineers who had the foresight and initiative to carefully track the technology on the road to discover problems as early as possible. Not only can monitoring help engineers identify problems that surface in the field, it can also assist them in their efforts to mobilize resources to resolve problem.

Happy software developers solve problems better: psychological measurements in empirical software engineering

PubMed Central

Wang, Xiaofeng; Abrahamsson, Pekka

2014-01-01

For more than thirty years, it has been claimed that a way to improve software developers’ productivity and software quality is to focus on people and to provide incentives to make developers satisfied and happy. This claim has rarely been verified in software engineering research, which faces an additional challenge in comparison to more traditional engineering fields: software development is an intellectual activity and is dominated by often-neglected human factors (called human aspects in software engineering research). Among the many skills required for software development, developers must possess high analytical problem-solving skills and creativity for the software construction process. According to psychology research, affective states—emotions and moods—deeply influence the cognitive processing abilities and performance of workers, including creativity and analytical problem solving. Nonetheless, little research has investigated the correlation between the affective states, creativity, and analytical problem-solving performance of programmers. This article echoes the call to employ psychological measurements in software engineering research. We report a study with 42 participants to investigate the relationship between the affective states, creativity, and analytical problem-solving skills of software developers. The results offer support for the claim that happy developers are indeed better problem solvers in terms of their analytical abilities. The following contributions are made by this study: (1) providing a better understanding of the impact of affective states on the creativity and analytical problem-solving capacities of developers, (2) introducing and validating psychological measurements, theories, and concepts of affective states, creativity, and analytical-problem-solving skills in empirical software engineering, and (3) raising the need for studying the human factors of software engineering by employing a multidisciplinary viewpoint. PMID:24688866

Happy software developers solve problems better: psychological measurements in empirical software engineering.

PubMed

Graziotin, Daniel; Wang, Xiaofeng; Abrahamsson, Pekka

2014-01-01

For more than thirty years, it has been claimed that a way to improve software developers' productivity and software quality is to focus on people and to provide incentives to make developers satisfied and happy. This claim has rarely been verified in software engineering research, which faces an additional challenge in comparison to more traditional engineering fields: software development is an intellectual activity and is dominated by often-neglected human factors (called human aspects in software engineering research). Among the many skills required for software development, developers must possess high analytical problem-solving skills and creativity for the software construction process. According to psychology research, affective states-emotions and moods-deeply influence the cognitive processing abilities and performance of workers, including creativity and analytical problem solving. Nonetheless, little research has investigated the correlation between the affective states, creativity, and analytical problem-solving performance of programmers. This article echoes the call to employ psychological measurements in software engineering research. We report a study with 42 participants to investigate the relationship between the affective states, creativity, and analytical problem-solving skills of software developers. The results offer support for the claim that happy developers are indeed better problem solvers in terms of their analytical abilities. The following contributions are made by this study: (1) providing a better understanding of the impact of affective states on the creativity and analytical problem-solving capacities of developers, (2) introducing and validating psychological measurements, theories, and concepts of affective states, creativity, and analytical-problem-solving skills in empirical software engineering, and (3) raising the need for studying the human factors of software engineering by employing a multidisciplinary viewpoint.

Implementing model-based system engineering for the whole lifecycle of a spacecraft

NASA Astrophysics Data System (ADS)

Fischer, P. M.; Lüdtke, D.; Lange, C.; Roshani, F.-C.; Dannemann, F.; Gerndt, A.

2017-09-01

Design information of a spacecraft is collected over all phases in the lifecycle of a project. A lot of this information is exchanged between different engineering tasks and business processes. In some lifecycle phases, model-based system engineering (MBSE) has introduced system models and databases that help to organize such information and to keep it consistent for everyone. Nevertheless, none of the existing databases approached the whole lifecycle yet. Virtual Satellite is the MBSE database developed at DLR. It has been used for quite some time in Phase A studies and is currently extended for implementing it in the whole lifecycle of spacecraft projects. Since it is unforeseeable which future use cases such a database needs to support in all these different projects, the underlying data model has to provide tailoring and extension mechanisms to its conceptual data model (CDM). This paper explains the mechanisms as they are implemented in Virtual Satellite, which enables extending the CDM along the project without corrupting already stored information. As an upcoming major use case, Virtual Satellite will be implemented as MBSE tool in the S2TEP project. This project provides a new satellite bus for internal research and several different payload missions in the future. This paper explains how Virtual Satellite will be used to manage configuration control problems associated with such a multi-mission platform. It discusses how the S2TEP project starts using the software for collecting the first design information from concurrent engineering studies, then making use of the extension mechanisms of the CDM to introduce further information artefacts such as functional electrical architecture, thus linking more and more processes into an integrated MBSE approach.

The Problem-Solving Process in Physics as Observed When Engineering Students at University Level Work in Groups

ERIC Educational Resources Information Center

Gustafsson, Peter; Jonsson, Gunnar; Enghag, Margareta

2015-01-01

The problem-solving process is investigated for five groups of students when solving context-rich problems in an introductory physics course included in an engineering programme. Through transcripts of their conversation, the paths in the problem-solving process have been traced and related to a general problem-solving model. All groups exhibit…

Un-Building Blocks: A Model of Reverse Engineering and Applicable Heuristics

DTIC Science & Technology

2015-12-01

CONCLUSIONS The machine does not isolate man from the great problems of nature but plunges him more deeply into them. Antoine de Saint-Exupery— Wind ...DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words) Reverse engineering is the problem -solving activity that ensues when one takes a...Douglas Moses, Vice Provost for Academic Affairs iv THIS PAGE INTENTIONALLY LEFT BLANK v ABSTRACT Reverse engineering is the problem -solving

Complex Approach to Conceptual Design of Machine Mechanically Extracting Oil from Jatropha curcas L. Seeds for Biomass-Based Fuel Production

PubMed Central

Mašín, Ivan

2016-01-01

One of important sources of biomass-based fuel is Jatropha curcas L. Great attention is paid to the biofuel produced from the oil extracted from the Jatropha curcas L. seeds. A mechanised extraction is the most efficient and feasible method for oil extraction for small-scale farmers but there is a need to extract oil in more efficient manner which would increase the labour productivity, decrease production costs, and increase benefits of small-scale farmers. On the other hand innovators should be aware that further machines development is possible only when applying the systematic approach and design methodology in all stages of engineering design. Systematic approach in this case means that designers and development engineers rigorously apply scientific knowledge, integrate different constraints and user priorities, carefully plan product and activities, and systematically solve technical problems. This paper therefore deals with the complex approach to design specification determining that can bring new innovative concepts to design of mechanical machines for oil extraction. The presented case study as the main part of the paper is focused on new concept of screw of machine mechanically extracting oil from Jatropha curcas L. seeds. PMID:27668259

Velocity Potential in Engineering Hydraulics versus Force Potential in Groundwater Dynamics

NASA Astrophysics Data System (ADS)

Weyer, K.

2013-12-01

Within engineering practice, the calculation of subsurface flow is dominated by the mathematical pseudo-physics of the engineer's adaptation of continuum methods to mechanics. Continuum mechanics rose to prominence in the 19th century in an successful attempt to solve practical engineering problems. To that end were put in place quite a number of simplifications in geometry and the properties of water and other fluids, as well as simplifications of Darcy's equation, in order to find reasonable answers to practical problems by making use of analytical equations. The proof of the correctness of the approach and its usefulness was in the practicability of results obtained. In the 1930s, a diametrically-opposed duality developed in the theoretical derivation of the laws of subsurface fluid flow between Muskat's (1937) velocity potential (engineering hydraulics) and Hubbert's (1940) force potential. The conflict between these authors lasted a lifetime. In the end Hubbert stated on one occasion that Muskat formulates a refined mathematics but does not know what it means in physical terms. In this author's opinion that can still be said about the application of continuum mechanics by engineers to date, as for example to CO2 sequestration, regional groundwater flow, oil sands work, and geothermal studies. To date, engineering hydraulics is best represented by Bear (1972) and de Marsily (1986). In their well-known textbooks, both authors refer to Hubbert's work as the proper way to deal with the physics of compressible fluids. Water is a compressible fluid. The authors then ignore, however, their own insights (de Marsily states so explicitly, Bear does not) and proceed to deal with water as an incompressible fluid. At places both authors assume the pressure gradients to be the main driving force for flow of fluids in the subsurface. That is not, however, the case. Instead the pressure potential forces are caused by compression initiated by unused gravitational energy not required to overcome the resistance to downward flow in penetrated rocks. As one of the consequences, the engineering hydraulics concept of buoyancy forces does not comply with physics. In general the vectorial forces within gravitationally-driven flow systems are ignored when using engineering hydraulics. Scheidegger (1974, p. 79) states, however, verbatim and unequivocally: 'It is thus a force potential and not a velocity potential which governs flow through porous media' (emphasis added). This presentation will outline the proper forces for groundwater flow and their calculations based on Hubbert's force potential and additional physical insights by Weyer (1978). REFERENCES Bear, J. 1972. Dynamics of Fluids in Porous Media. American Elsevier Publishing Company, Inc., New York, NY, USA. de Marsily, G. 1986. Quantitative Hydrogeology: Groundwater Hydrology for Engineers. Academic Press, San Diego, California, USA. Hubbert, M.K. 1940. The theory of groundwater motion. Journal of Geology 48(8): 785-944. Muskat, Morris, 1937. The flow of homogeneous fluids through porous media. McGraw-Hill Book Company Inc., New York, NY, USA Scheidegger. A.E., 1974. The physics of flow through permeable media. Third Edition. University of Toronto Press, Toronto, Ontario, Canada Weyer, K.U., 1978. Hydraulic forces in permeable media. Bulletin du B.R.G.M., Vol. 91, pp. 286-297, Orléans, France.

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.

Rehabilitation Engineering Sourcebook [and] Rehabilitation Engineering Sourcebook Supplement I.

ERIC Educational Resources Information Center

Institute for Information Studies, Falls Church, VA.

Intended for use by rehabilitation counselors and work supervisors, the sourcebook contains 173 problems and solutions provided by rehabilitation engineering. A section titled "Guidelines for Formulating Problem Statements" is intended to summarize the most effective ways for either disabled individuals or rehabilitation practitioners to…

A Coding Scheme for Analysing Problem-Solving Processes of First-Year Engineering Students

ERIC Educational Resources Information Center

Grigg, Sarah J.; Benson, Lisa C.

2014-01-01

This study describes the development and structure of a coding scheme for analysing solutions to well-structured problems in terms of cognitive processes and problem-solving deficiencies for first-year engineering students. A task analysis approach was used to assess students' problem solutions using the hierarchical structure from a…

Designing Biomimetic Materials from Marine Organisms.

PubMed

Nichols, William T

2015-01-01

Two biomimetic design approaches that apply biological solutions to engineering problems are discussed. In the first case, motivation comes from an engineering problem and the key challenge is to find analogous biological functions and map them into engineering materials. We illustrate with an example of water pollution remediation through appropriate design of a biomimetic sponge. In the second case, a biological function is already known and the challenge is to identify the appropriate engineering problem. We demonstrate the biological approach with marine diatoms that control energy and materials at their surface providing inspiration for a number of engineering applications. In both cases, it is essential to select materials and structures at the nanoscale to control energy and materials flows at interfaces.

Resource Isolation Method for Program’S Performance on CMP

NASA Astrophysics Data System (ADS)

Guan, Ti; Liu, Chunxiu; Xu, Zheng; Li, Huicong; Ma, Qiang

2017-10-01

Data center and cloud computing are more popular, which make more benefits for customers and the providers. However, in data center or clusters, commonly there is more than one program running on one server, but programs may interference with each other. The interference may take a little effect, however, the interference may cause serious drop down of performance. In order to avoid the performance interference problem, the mechanism of isolate resource for different programs is a better choice. In this paper we propose a light cost resource isolation method to improve program’s performance. This method uses Cgroups to set the dedicated CPU and memory resource for a program, aiming at to guarantee the program’s performance. There are three engines to realize this method: Program Monitor Engine top program’s resource usage of CPU and memory and transfer the information to Resource Assignment Engine; Resource Assignment Engine calculates the size of CPU and memory resource should be applied for the program; Cgroups Control Engine divide resource by Linux tool Cgroups, and drag program in control group for execution. The experiment result show that making use of the resource isolation method proposed by our paper, program’s performance can be improved.

Model verification of mixed dynamic systems. [POGO problem in liquid propellant rockets

NASA Technical Reports Server (NTRS)

Chrostowski, J. D.; Evensen, D. A.; Hasselman, T. K.

1978-01-01

A parameter-estimation method is described for verifying the mathematical model of mixed (combined interactive components from various engineering fields) dynamic systems against pertinent experimental data. The model verification problem is divided into two separate parts: defining a proper model and evaluating the parameters of that model. The main idea is to use differences between measured and predicted behavior (response) to adjust automatically the key parameters of a model so as to minimize response differences. To achieve the goal of modeling flexibility, the method combines the convenience of automated matrix generation with the generality of direct matrix input. The equations of motion are treated in first-order form, allowing for nonsymmetric matrices, modeling of general networks, and complex-mode analysis. The effectiveness of the method is demonstrated for an example problem involving a complex hydraulic-mechanical system.

Evaluating learning and teaching using the Force Concept Inventory

NASA Astrophysics Data System (ADS)

Zitzewitz, Paul

1997-04-01

Teaching methods used in the calculus-based mechanics course for engineers and scientists (P150) at the University of Michigan-Dearborn were markedly changed in September, 1996. Lectures emphasize active learning with Mazur's ConcepTests, Sokoloff's Interactive Demonstrations, and Van Heuvelen's ALPS Kit worksheets. Students solve context-rich problems using Van Heuvelen's multiple representation format in cooperative groups in discussion sections. Labs were changed to use MBL emphasizing concepts and Experiment Problems to learn lab-based problem solving. Pre- and post-testing of 400 students with the Force Concept Inventory has demonstrated considerable success. The average increase in score has been 35-45methods as defined by Hake. The methods and results will be discussed. Detailed analyses of the FCI results will look at success in teaching specific concepts and the effect of student preparation in mathematics and high school physics.

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…

NASA Engineering and Technology Advancement Office: A proposal to the administrator

NASA Technical Reports Server (NTRS)

Schulze, Norman R.

1993-01-01

NASA has continually had problems with cost, schedule, performance, reliability, quality, and safety aspects in programs. Past solutions have not provided the answers needed, and a major change is needed in the way of doing business. A new approach is presented for consideration. These problems are all engineering matters, and therefore, require engineering solutions. Proper engineering tools are needed to fix engineering problems. Headquarters is responsible for providing the management structure to support programs with appropriate engineering tools. A guide to define those tools and an approach for putting them into place is provided. Recommendations include establishing a new Engineering and Technology Advancement Office, requesting a review of this proposal by the Administrator since this subject requires a top level decision. There has been a wide peer review conducted by technical staff at Headquarters, the Field Installations, and others in industry as discussed.

The Detection of Radiated Modes from Ducted Fan Engines

NASA Technical Reports Server (NTRS)

Farassat, F.; Nark, Douglas M.; Thomas, Russell H.

2001-01-01

The bypass duct of an aircraft engine is a low-pass filter allowing some spinning modes to radiate outside the duct. The knowledge of the radiated modes can help in noise reduction, as well as the diagnosis of noise generation mechanisms inside the duct. We propose a nonintrusive technique using a circular microphone array outside the engine measuring the complex noise spectrum on an arc of a circle. The array is placed at various axial distances from the inlet or the exhaust of the engine. Using a model of noise radiation from the duct, an overdetermined system of linear equations is constructed for the complex amplitudes of the radial modes for a fixed circumferential mode. This system of linear equations is generally singular, indicating that the problem is illposed. Tikhonov regularization is employed to solve this system of equations for the unknown amplitudes of the radiated modes. An application of our mode detection technique using measured acoustic data from a circular microphone array is presented. We show that this technique can reliably detect radiated modes with the possible exception of modes very close to cut-off.

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

The 7.5K lbf thrust engine preliminary design for Orbit Transfer Vehicle

NASA Technical Reports Server (NTRS)

Hayden, Warren R.; Sabiers, Ralph; Schneider, Judy

1994-01-01

This document summarizes the preliminary design of the Aerojet version of the Orbit Transfer Vehicle main engine. The concept of a 7500 lbf thrust LO2/GH2 engine using the dual expander cycle for optimum efficiency is validated through power balance and thermal calculations. The engine is capable of 10:1 throttling from a nominal 2000 psia to a 200 psia chamber pressure. Reservations are detailed on the feasibility of a tank head start, but the design incorporates low speed turbopumps to mitigate the problem. The mechanically separate high speed turbopumps use hydrostatic bearings to meet engine life requirements, and operate at sub-critical speed for better throttling ability. All components were successfully packaged in the restricted envelope set by the clearances for the extendible/retractable nozzle. Gimbal design uses an innovative primary and engine out gimbal system to meet the +/- 20 deg gimbal requirement. The hydrogen regenerator and LOX/GH2 heat exchanger uses the Aerojet platelet structures approach for a highly compact component design. The extendible/retractable nozzle assembly uses an electric motor driven jack-screw design and a one segment carbon-carbon or silicide coated columbium nozzle with an area ratio, when extended, of 1430:1. A reliability analysis and risk assessment concludes the report.

Problem-based learning biotechnology courses in chemical engineering.

PubMed

Glatz, Charles E; Gonzalez, Ramon; Huba, Mary E; Mallapragada, Surya K; Narasimhan, Balaji; Reilly, Peter J; Saunders, Kevin P; Shanks, Jacqueline V

2006-01-01

We have developed a series of upper undergraduate/graduate lecture and laboratory courses on biotechnological topics to supplement existing biochemical engineering, bioseparations, and biomedical engineering lecture courses. The laboratory courses are based on problem-based learning techniques, featuring two- and three-person teams, journaling, and performance rubrics for guidance and assessment. Participants initially have found them to be difficult, since they had little experience with problem-based learning. To increase enrollment, we are combining the laboratory courses into 2-credit groupings and allowing students to substitute one of them for the second of our 2-credit chemical engineering unit operations laboratory courses.

Research in the comprehension of engineering lectures by non-native speakers

NASA Technical Reports Server (NTRS)

Olsen, L. A.; Huckin, T. N.

1981-01-01

Failure by foreign students to perceive the rhetorical structure or overall organization of an engineering lecture, rendering them unable to understand it, is discussed. Equally serious failure by such students to perceive the organizing role of theory in structuring the activities in their field is reported. Failure to identify the role of theory in the problem-solving process that underlies engineering is emphasized. Engineering was not seen as a series of on-going problems where each stage of solution exposed new problems to be solved. Implications for course planners and material designers are discussed.

A Sequential Shifting Algorithm for Variable Rotor Speed Control

NASA Technical Reports Server (NTRS)

Litt, Jonathan S.; Edwards, Jason M.; DeCastro, Jonathan A.

2007-01-01

A proof of concept of a continuously variable rotor speed control methodology for rotorcraft is described. Variable rotor speed is desirable for several reasons including improved maneuverability, agility, and noise reduction. However, it has been difficult to implement because turboshaft engines are designed to operate within a narrow speed band, and a reliable drive train that can provide continuous power over a wide speed range does not exist. The new methodology proposed here is a sequential shifting control for twin-engine rotorcraft that coordinates the disengagement and engagement of the two turboshaft engines in such a way that the rotor speed may vary over a wide range, but the engines remain within their prescribed speed bands and provide continuous torque to the rotor; two multi-speed gearboxes facilitate the wide rotor speed variation. The shifting process begins when one engine slows down and disengages from the transmission by way of a standard freewheeling clutch mechanism; the other engine continues to apply torque to the rotor. Once one engine disengages, its gear shifts, the multi-speed gearbox output shaft speed resynchronizes and it re-engages. This process is then repeated with the other engine. By tailoring the sequential shifting, the rotor may perform large, rapid speed changes smoothly, as demonstrated in several examples. The emphasis of this effort is on the coordination and control aspects for proof of concept. The engines, rotor, and transmission are all simplified linear models, integrated to capture the basic dynamics of the problem.

Space-Time Conservation Element and Solution Element Method Being Developed

NASA Technical Reports Server (NTRS)

Chang, Sin-Chung; Himansu, Ananda; Jorgenson, Philip C. E.; Loh, Ching-Yuen; Wang, Xiao-Yen; Yu, Sheng-Tao

1999-01-01

The engineering research and design requirements of today pose great computer-simulation challenges to engineers and scientists who are called on to analyze phenomena in continuum mechanics. The future will bring even more daunting challenges, when increasingly complex phenomena must be analyzed with increased accuracy. Traditionally used numerical simulation methods have evolved to their present state by repeated incremental extensions to broaden their scope. They are reaching the limits of their applicability and will need to be radically revised, at the very least, to meet future simulation challenges. At the NASA Lewis Research Center, researchers have been developing a new numerical framework for solving conservation laws in continuum mechanics, namely, the Space-Time Conservation Element and Solution Element Method, or the CE/SE method. This method has been built from fundamentals and is not a modification of any previously existing method. It has been designed with generality, simplicity, robustness, and accuracy as cornerstones. The CE/SE method has thus far been applied in the fields of computational fluid dynamics, computational aeroacoustics, and computational electromagnetics. Computer programs based on the CE/SE method have been developed for calculating flows in one, two, and three spatial dimensions. Results have been obtained for numerous problems and phenomena, including various shock-tube problems, ZND detonation waves, an implosion and explosion problem, shocks over a forward-facing step, a blast wave discharging from a nozzle, various acoustic waves, and shock/acoustic-wave interactions. The method can clearly resolve shock/acoustic-wave interactions, wherein the difference of the magnitude between the acoustic wave and shock could be up to six orders. In two-dimensional flows, the reflected shock is as crisp as the leading shock. CE/SE schemes are currently being used for advanced applications to jet and fan noise prediction and to chemically reacting flows.

Start Up Research Effort in Fluid Mechanics. Advanced Methods for Acoustic and Thrust Benefits for Aircraft Engine Nozzle

NASA Technical Reports Server (NTRS)

White, Samuel G.; Gilinsky, Mikhail M.

1997-01-01

In accordance with the project plan for the report period in the proposal titled above, HU and FML teams investigated two sets of concepts for reduction of noise and improvement in efficiency for jet exhaust nozzles of aircraft engines and screws for mixers, fans, propellers and boats. The main achievements in the report period are: (a) Publication of the paper in the AIAA Journal, which described our concepts and some results. (b) The Award in the Civil Research and Development Foundation (CRDF) competition. This 2 year grant for Hampton University (HU) and Central AeroHydrodynamic Institute (TSAGI, Moscow, Russia) supports the research implementation under the current NASA FAR grant. (c) Selection for funding by NASA HQ review panel of the Partnership Awards Concept Paper. This two year grant also will support our current FAR grant. (d) Publication of a Mobius Strip concept in NASA Technical Briefs, June, 1996, and a great interest of many industrial companies in this invention. Successful experimental results with the Mobius shaped screw for mixers, which save more than 30% of the electric power by comparison with the standard screws. Creation of the scientific-popular video-film which can be used for commercial and educational purposes. (e) Organization work, joint meetings and discussions of the NASA LARC JNL Team and HU professors and administration for the solution of actual problems and effective work of the Fluid Mechanics Laboratory at Hampton University. In this report the main designs are enumerated. It also contains for both concept sets: (1) the statement of the problem for each design, some results, publications, inventions, patents, our vision for continuation of this research, and (2) present and expected problems in the future.

Cellulose acetate based 3-dimensional electrospun scaffolds for skin tissue engineering applications.

PubMed

Atila, Deniz; Keskin, Dilek; Tezcaner, Ayşen

2015-11-20

Skin defects that are not able to regenerate by themselves are among the major problems faced. Tissue engineering approach holds promise for treating such defects. Development of tissue-mimicking-scaffolds that can promote healing process receives an increasing interest in recent years. In this study, 3-dimensional electrospun cellulose acetate (CA) pullulan (PULL) scaffolds were developed for the first time. PULL was intentionally used to obtain 3D structures with adjustable height. It was removed from the electrospun mesh to increase the porosity and biostability. Different ratios of the polymers were electrospun and analyzed with respect to degradation, porosity, and mechanical properties. It has been observed that fiber diameter, thickness and porosity of scaffolds increased with increased PULL content, on the other hand this resulted with higher degradation of scaffolds. Mechanical strength of scaffolds was improved after PULL removal suggesting their suitability as cell carriers. Cell culture studies were performed with the selected scaffold group (CA/PULL: 50/50) using mouse fibroblastic cell line (L929). In vitro cell culture tests showed that cells adhered, proliferated and populated CA/PULL (50/50) scaffolds showing that they are cytocompatible. Results suggest that uncrosslinked CA/PULL (50/50) electrospun scaffolds hold potential for skin tissue engineering applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

Toward GPGPU accelerated human electromechanical cardiac simulations

PubMed Central

Vigueras, Guillermo; Roy, Ishani; Cookson, Andrew; Lee, Jack; Smith, Nicolas; Nordsletten, David

2014-01-01

In this paper, we look at the acceleration of weakly coupled electromechanics using the graphics processing unit (GPU). Specifically, we port to the GPU a number of components of Heart—a CPU-based finite element code developed for simulating multi-physics problems. On the basis of a criterion of computational cost, we implemented on the GPU the ODE and PDE solution steps for the electrophysiology problem and the Jacobian and residual evaluation for the mechanics problem. Performance of the GPU implementation is then compared with single core CPU (SC) execution as well as multi-core CPU (MC) computations with equivalent theoretical performance. Results show that for a human scale left ventricle mesh, GPU acceleration of the electrophysiology problem provided speedups of 164 × compared with SC and 5.5 times compared with MC for the solution of the ODE model. Speedup of up to 72 × compared with SC and 2.6 × compared with MC was also observed for the PDE solve. Using the same human geometry, the GPU implementation of mechanics residual/Jacobian computation provided speedups of up to 44 × compared with SC and 2.0 × compared with MC. © 2013 The Authors. International Journal for Numerical Methods in Biomedical Engineering published by John Wiley & Sons, Ltd. PMID:24115492

Study on the engine oil's wear based on the flash point

NASA Astrophysics Data System (ADS)

Niculescu, R.; Iorga-Simăn, V.; Trică, A.; Clenci, A.

2016-08-01

Increasing energy performance of internal combustion engines is largely influenced by frictional forces that arise between moving parts. Thus, in this respect, the nature and quality of the engine oil used is an important factor. Equally important is the effect of various engine injection strategies upon the oil quality. In other words, it's of utmost importance to maintain the quality of engine oil during engine's operation. Oil dilution is one of the most common causes that lead to its wear, creating lubrication problems. Moreover, at low temperatures operating conditions, the oil dilution with diesel fuel produces wax. When starting the engine, this may lead to lubrication deficiencies and even oil starvation with negative consequences on the engine mechanism parts wear (piston, rings and cylinders) but also crankcase bearings wear.Engine oil dilution with diesel fuel have several causes: wear of rings and/or injectors, late post-injection strategy for the sake of particulate filter regeneration, etc.This paper presents a study on the degree of deterioration of engine oils as a result of dilution with diesel fuel. The analysed oils used for this study were taken from various models of engines equipped with diesel particulate filter. The assessment is based on the determination of oil flash point and dilution degree using the apparatus Eraflash produced by Eralytics, Austria. Eraflash measurement is directly under the latest and safest standards ASTM D6450 & D7094), which are in excellent correlation with ASTM D93 Pensky - Martens ASTM D56 TAG methods; it uses the Continuous Closed Cup method for finding the Flash Point (CCCFP).

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…

Acoustical consulting-Reflections on a challenging career

NASA Astrophysics Data System (ADS)

Braslau, David

2004-05-01

The acoustical consulting profession can be entered in a number of ways. The most direct approach is to obtain a degree in acoustics and join a large consulting firm immediately after graduation. Acoustical consulting can also be entered indirectly from various fields of engineering or physics which can provide a somewhat broader background. These disciplines might include, for example, structural engineering and structural dynamics, mechanics of materials, dynamic behavior of solids or geophysics. Acoustical consulting specialization can be very broad or very narrow as seen from the National Council of Acoustical Consultants capability listing. As an acoustical consultant, one must address a wide range of problems which provides both the challenges and joys of this profession. Technical capabilities and professional judgment are constantly developed from exposure to these problems and through interaction with other members of the profession. Selected case studies including sound isolation in buildings, noise and vibration from blasting, control of noise from environmental sources, acoustical design of classrooms and performing spaces, and product design demonstrate the variety of challenges faced by an acoustical consultant.

The Tao of Microelectronics

NASA Astrophysics Data System (ADS)

Zhang, Yumin

2014-12-01

Microelectronics is a challenging course to many undergraduate students and is often described as very messy. Before taking this course, all the students have learned circuit analysis, where basically all the problems can be solved by applying Kirchhoff's laws. In addition, most engineering students have also learned engineering mechanics: statics and dynamics, where Newton's laws and related principles can be applied in solving all the problems. However, microelectronics is not as clean as these courses. There are hundreds of equations for different circuits, and it is impossible to remember which equation should be applied to which circuit. One of the common pitfalls in learning this course is over-focusing at the equation level and ignoring the ideas (Tao) behind it. Unfortunately, these ideas are not summarized and emphasized in most microelectronics textbooks, though they cover various electronic circuits comprehensively. Therefore, most undergraduate students feel at a loss when they start to learn this topic. This book tries to illustrate the major ideas and the basic analysis techniques, so that students can derive the right equations easily when facing an electronic circuit.

Automation of Tooling Backup and Cutter Selection for Engineering Production

NASA Astrophysics Data System (ADS)

Terekhov, M. V.; Averchenkov, V. I.; Reutov, A. A.; Handozhko, A. V.

2017-01-01

This paper reports the analysis of a tool support procedure for mechanical engineering and basic trends in the automation of this field are revealed. The system of technical-organizational measures directed at the formation, management and development of the tool stock and a high degree of technological readiness of manufacturing are described. The problems of an automated optimum cutter selection are considered. A mathematical support for a choice of cutters with through-away tips is described. A simulator for the description of combined cutters is presented. Basic criteria defining cutter choice are established. The problem of a multi-criterion fuzzy estimation of alternatives at different significance of choice criteria is solved. The criterion significance ranking at the parameter choice of cutter plates and tool supports is carried out. A set of estimations of cutter plate forms and other cutter parameters taking into account a relative significance of criteria is defined. The application of a decisive rule in the choice of an alternative required is described, which consists in the definition of the intersection of sets of alternative estimations.

Inducible CRISPR genome-editing tool: classifications and future trends.

PubMed

Dai, Xiaofeng; Chen, Xiao; Fang, Qiuwu; Li, Jia; Bai, Zhonghu

2018-06-01

The discovery of CRISPR-Cas9/dCas9 system has reinforced our ability and revolutionized our history in genome engineering. While Cas9 and dCas9 are programed to modulate gene expression by introducing DNA breaks, blocking transcription factor recruitment or dragging functional groups towards the targeted sites, sgRNAs determine the genomic loci where the modulation occurs. The off-target problem, due to limited sgRNA specificity and genome complexity of many species, has posed concerns for the wide application of this revolutionary technique. To solve this problem and, more importantly, gain power over gene functionality and cell fate control, inducible strategies have been continuously evolved to offer tailored solutions to address specific biological questions. By reviewing recent advances in inducible CRISPR system design and critical elements potentially adding values to such systems, we classify current approaches in this domain into four mechanically distinct categories, namely, "split system", "allosteric system", "combinatorial system", and "transient delivery system", discuss the pros and cons of each system, and point out the under-explored areas and future directions, with the aim of enriching our toolbox of delicate life engineering.

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

Collaborative Systems Thinking: A Response to the Problems Faced by Systems Engineering's 'Middle Tier'

NASA Technical Reports Server (NTRS)

Phfarr, Barbara B.; So, Maria M.; Lamb, Caroline Twomey; Rhodes, Donna H.

2009-01-01

Experienced systems engineers are adept at more than implementing systems engineering processes: they utilize systems thinking to solve complex engineering problems. Within the space industry demographics and economic pressures are reducing the number of experienced systems engineers that will be available in the future. Collaborative systems thinking within systems engineering teams is proposed as a way to integrate systems engineers of various experience levels to handle complex systems engineering challenges. This paper uses the GOES-R Program Systems Engineering team to illustrate the enablers and barriers to team level systems thinking and to identify ways in which performance could be improved. Ways NASA could expand its engineering training to promote team-level systems thinking are proposed.

Fatigue and Fracture Branch: A compendium of recently completed and on-going research projects

NASA Technical Reports Server (NTRS)

Elber, W.

1984-01-01

This compendium of recently completed and ongoing research projects from the Fatigue and Fracture Branch at NASA Langley Research Center provides technical descriptions and key results of all such projects expected to lead to publication of significant findings. The common thread to all these studies is the application of fracture mechanics analyses to engineering problems in metals and composites, with particular emphasis on airframe structural materials. References to recent publications are included where appropriate.

Chesapeake Bay Tidal Flooding Study. Appendix A. Problem Identification. Appendix B. Plan Formulation, Assessment and Evaluation. Appendix C. Recreation and Natural Resources.

DTIC Science & Technology

1984-09-01

principal coordinating mechanism for the Study. Since its establishment, the Advisory Group advised the District Engineer regarding study policy and...standards. Finfish in the vicinity of Tilghrnan Island include those species typical for Bay waters having a salinity of 9-14 parts per thousand (ppt...usually reaches its highest point during the year in January and February, reflecting the area’s dependence on farming and fisheries. INSTITUTIONAL

Elementary metallography

NASA Technical Reports Server (NTRS)

Kazem, Sayyed M.

1992-01-01

Materials and Processes 1 (MET 141) is offered to freshmen by the Mechanical Engineering Department at Purdue University. The goal of MET 141 is to broaden the technical background of students who have not had any college science courses. Hence, applied physics, chemistry, and mathematics are included and quantitative problem solving is involved. In the elementary metallography experiment of this course, the objectives are: (1) introduce the vocabulary and establish outlook; (2) make qualitative observations and quantitative measurements; (3) demonstrate the proper use of equipment; and (4) review basic mathematics and science.

Status and Direction of Tribology as a Science in the 80's. Understanding and Prediction

NASA Technical Reports Server (NTRS)

Tabor, D.

1984-01-01

The most challenging research problems in tribology for the next decade or beyond are classified horizontally into two categories: (1) understanding of basic mechanisms and (2) prediction of practical performance. Vertical classifications are in terms of particular themes or fields of interest. Areas where more fundamental work is required are: adhesion and friction of clean and contaminated surfaces; lubrication; new materials; surface characterization at the engineering level (topography) and at the atomic levels (various spectroscopies); and wear.

THE NUCLEAR RAMJET PROPULSION SYSTEM

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

Merkle, T.C.

1959-06-30

The most practical nuclear ramjet systems consist of a suituble inlet diffusor system followed by a singlepass, straight-through heat exchanger (reactor) which couples into a typical exhaust nozzle. Within this framework, possibilities ars governed by the aerodynamic requirements of flight, the nuclear requirements of the reactor, the chemical problems associated with breathing air, and the mechanical properties of materials at elevated temperatures. The major research and development areas which must be entered in the actual production of such an engine are discussed. (W.D.M.)

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

Doering, C.; Bier, M.; Christodoulou, K.

This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Polymers, composites, and synthetic modern materials are replacing traditional materials in many older scientific, engineering, commercial, and military applications. This project sought to focus on the new polymeric materials, deriving and analyzing models that predict their seemingly mysterious transport properties. It sought to identify the dominant physical mechanisms and the pertinent dimensionless parameters, produce viable theoretical models, and devise asymptotic and numerical methods for use in specific problems.

Process Inquiry: Analysis of Oral Problem-Solving Skills in Mathematics of Engineering Students

ERIC Educational Resources Information Center

Trance, Naci John C.

2013-01-01

This paper presents another effort in determining the difficulty of engineering students in terms of solving word problems. Students were presented with word problems in algebra. Then, they were asked to solve the word problems orally; that is, before they presented their written solutions, they were required to explain how they understood the…

Avoid, Control, Succumb, or Balance: Engineering Students' Approaches to a Wicked Sustainability Problem

ERIC Educational Resources Information Center

Lönngren, Johanna; Ingerman, Åke; Svanström, Magdalena

2017-01-01

Wicked sustainability problems (WSPs) are an important and particularly challenging type of problem. Science and engineering education can play an important role in preparing students to deal with such problems, but current educational practice may not adequately prepare students to do so. We address this gap by providing insights related to…

Solving mixed integer nonlinear programming problems using spiral dynamics optimization algorithm

NASA Astrophysics Data System (ADS)

Kania, Adhe; Sidarto, Kuntjoro Adji

2016-02-01

Many engineering and practical problem can be modeled by mixed integer nonlinear programming. This paper proposes to solve the problem with modified spiral dynamics inspired optimization method of Tamura and Yasuda. Four test cases have been examined, including problem in engineering and sport. This method succeeds in obtaining the optimal result in all test cases.

Investigating and Developing Engineering Students' Mathematical Modelling and Problem-Solving Skills

ERIC Educational Resources Information Center

Wedelin, Dag; Adawi, Tom; Jahan, Tabassum; Andersson, Sven

2015-01-01

How do engineering students approach mathematical modelling problems and how can they learn to deal with such problems? In the context of a course in mathematical modelling and problem solving, and using a qualitative case study approach, we found that the students had little prior experience of mathematical modelling. They were also inexperienced…

Ingenuity in Action: Connecting Tinkering to Engineering Design Processes

ERIC Educational Resources Information Center

Wang, Jennifer; Werner-Avidon, Maia; Newton, Lisa; Randol, Scott; Smith, Brooke; Walker, Gretchen

2013-01-01

The Lawrence Hall of Science, a science center, seeks to replicate real-world engineering at the "Ingenuity in Action" exhibit, which consists of three open-ended challenges. These problems encourage children to engage in engineering design processes and problem-solving techniques through tinkering. We observed and interviewed 112…

Microfluidics: Science and Engineering at the Edge of the Continuum

NASA Astrophysics Data System (ADS)

Breuer, Kenny

2002-11-01

The widespread growth of microengineering and the development of a new generation of micron- and nanometer scale diagnostic techniques has focussed much recent attention on the mechanics of fluids at the micron and sub-micron scale. Challenges with both scientific and engineering relevance have been raised by this activity, ranging from the prediction of viscous damping and lubrication effects in MEMS to the design of microengines to the understanding of bacterial propulsion. Identifying and addressing these challenges form the basis of this talk. >From a scientific perspective, a question that refuses to die is that of the applicability of the continuum hypothesis, and the possible existence of new physical phenomena only observable in small systems. To be brief, the reports of the demise of the Navier-Stokes equations are greatly exaggerated and to illustrate this we will review the more recent work on near-continuum fluid mechanics in micron and sub-micron scale devices with an emphasis on our own experiments on the breakdown of the continuum description in both gaseous and liquid flows. From an engineering perspective, the tight coupling between fluids, structures and manufacturing result in flows characterized by unfamiliar parameter regimes and unconventional geometries. We will look at several examples of such microfluidic engineering, drawn from MEMS (inertial instruments, microengines) and biology (bacterial propulsion) that illustrate the the unique design challenges that we encounter in microfluidic devices and the solutions (and lack of solutions) to these problems.

Software Past, Present, and Future: Views from Government, Industry and Academia

NASA Technical Reports Server (NTRS)

Holcomb, Lee; Page, Jerry; Evangelist, Michael

2000-01-01

Views from the NASA CIO NASA Software Engineering Workshop on software development from the past, present, and future are presented. The topics include: 1) Software Past; 2) Software Present; 3) NASA's Largest Software Challenges; 4) 8330 Software Projects in Industry Standish Groups 1994 Report; 5) Software Future; 6) Capability Maturity Model (CMM): Software Engineering Institute (SEI) levels; 7) System Engineering Quality Also Part of the Problem; 8) University Environment Trends Will Increase the Problem in Software Engineering; and 9) NASA Software Engineering Goals.

Teaching problem solving: Don't forget the problem solver(s)

NASA Astrophysics Data System (ADS)

Ranade, Saidas M.; Corrales, Angela

2013-05-01

The importance of intrapersonal and interpersonal intelligences has long been known but educators have debated whether to and how to incorporate those topics in an already crowded engineering curriculum. In 2010, the authors used the classroom as a laboratory to observe the usefulness of including selected case studies and exercises from the fields of neurology, artificial intelligence, cognitive sciences and social psychology in a new problem-solving course. To further validate their initial findings, in 2012, the authors conducted an online survey of engineering students and engineers. The main conclusion is that engineering students will benefit from learning more about the impact of emotions, culture, diversity and cognitive biases when solving problems. Specifically, the work shows that an augmented problem-solving curriculum needs to include lessons on labelling emotions and cognitive biases, 'evidence-based' data on the importance of culture and diversity and additional practice on estimating conditional probability.

Virtual and flexible digital signal processing system based on software PnP and component works

NASA Astrophysics Data System (ADS)

He, Tao; Wu, Qinghua; Zhong, Fei; Li, Wei

2005-05-01

An idea about software PnP (Plug & Play) is put forward according to the hardware PnP. And base on this idea, a virtual flexible digital signal processing system (FVDSPS) is carried out. FVDSPS is composed of a main control center, many sub-function modules and other hardware I/O modules. Main control center sends out commands to sub-function modules, and manages running orders, parameters and results of sub-functions. The software kernel of FVDSPS is DSP (Digital Signal Processing) module, which communicates with the main control center through some protocols, accept commands or send requirements. The data sharing and exchanging between the main control center and the DSP modules are carried out and managed by the files system of the Windows Operation System through the effective communication. FVDSPS real orients objects, orients engineers and orients engineering problems. With FVDSPS, users can freely plug and play, and fast reconfigure a signal process system according to engineering problems without programming. What you see is what you get. Thus, an engineer can orient engineering problems directly, pay more attention to engineering problems, and promote the flexibility, reliability and veracity of testing system. Because FVDSPS orients TCP/IP protocol, through Internet, testing engineers, technology experts can be connected freely without space. Engineering problems can be resolved fast and effectively. FVDSPS can be used in many fields such as instruments and meter, fault diagnosis, device maintenance and quality control.

A novel safety device with metal counter meshing gears discriminator directly driven by axial flux permanent magnet micromotors based on MEMS technology

NASA Astrophysics Data System (ADS)

Zhang, Weiping; Chen, Wenyuan; Zhao, Xiaolin; Li, Shengyong; Jiang, Yong

2005-08-01

In a novel safety device based on MEMS technology for high consequence systems, the discriminator consists of two groups of metal counter meshing gears and two pawl/ratchet wheel mechanisms. Each group of counter meshing gears is onepiece and driven directly by an axial flux permanent magnet micromotor respectively. The energy-coupling element is an optical shutter with two collimators and a coupler wheel. The safety device's probability is less than 1/106. It is fabricated by combination of an LiGA-like process and precision mechanical engineering. The device has simple structure, few dynamic problems, high strength and strong reliability.

Pip pin reliability and design

NASA Technical Reports Server (NTRS)

Skyles, Lane P.

1994-01-01

Pip pins are used in many engineering applications. Of particular interest to the aerospace industry is their use in various mechanism designs. Many payloads that fly aboard our nation's Space Shuttle have at least one actuated mechanism. Often these mechanisms incorporate pip pins in their design in order to fasten interfacing parts or joints. Pip pins are most often used when an astronaut will have a direct interface with the mechanism. This interfacing can be done during Space Shuttle mission EVA's (ExtraVehicular Activity). The main reason for incorporating pip pins is convenience and their ability to provide a quick release for interfacing parts. However, there are some issues that must be taken into account when using them in a design. These issues include documented failures and quality control problems when using substandard pip pins. A history of pip pins as they relate to the aerospace industry as well as general design features is discussed.

Metabolic Engineering for Substrate Co-utilization

NASA Astrophysics Data System (ADS)

Gawand, Pratish

Production of biofuels and bio-based chemicals is being increasingly pursued by chemical industry to reduce its dependence on petroleum. Lignocellulosic biomass (LCB) is an abundant source of sugars that can be used for producing biofuels and bio-based chemicals using fermentation. Hydrolysis of LCB results in a mixture of sugars mainly composed of glucose and xylose. Fermentation of such a sugar mixture presents multiple technical challenges at industrial scale. Most industrial microorganisms utilize sugars in a sequential manner due to the regulatory phenomenon of carbon catabolite repression (CCR). Due to sequential utilization of sugars, the LCB-based fermentation processes suffer low productivities and complicated operation. Performance of fermentation processes can be improved by metabolic engineering of microorganisms to obtain superior characteristics such as high product yield. With increased computational power and availability of complete genomes of microorganisms, use of model-based metabolic engineering is now a common practice. The problem of sequential sugar utilization, however, is a regulatory problem, and metabolic models have never been used to solve such regulatory problems. The focus of this thesis is to use model-guided metabolic engineering to construct industrial strains capable of co-utilizing sugars. First, we develop a novel bilevel optimization algorithm SimUp, that uses metabolic models to identify reaction deletion strategies to force co-utilization of two sugars. We then use SimUp to identify reaction deletion strategies to force glucose-xylose co-utilization in Escherichia coli. To validate SimUp predictions, we construct three mutants with multiple gene knockouts and test them for glucose-xylose utilization characteristics. Two mutants, designated as LMSE2 and LMSE5, are shown to co-utilize glucose and xylose in agreement with SimUp predictions. To understand the molecular mechanism involved in glucose-xylose co-utilization of the mutant LMSE2, the mutant is subjected to targeted and whole genome sequencing. Finally, we use the mutant LMSE2 to produce D-ribose from a mixture of glucose and xylose by overexpressing an endogenous phosphatase. The methods developed in this thesis are anticipated to provide a novel approach to solve sugar co-utilization problem in industrial microorganisms, and provide insights into microbial response to forced co-utilization of sugars.

Challenges in the Japan Beyond-Brittle Project (JBBP) for EGS development beyond the brittle-ductile transition

NASA Astrophysics Data System (ADS)

Asanuma, H.; Muraoka, H.; Tsuchiya, N.; Ito, H.

2013-12-01

Development using Engineered Geothermal System (EGS) technologies is considered to be the best solution to the problems of the localized distribution of geothermal resources. However, it is considered that a number of problems, including low water recovery rate, difficulty in design of the reservoir, and induced earthquake, would appear in Japanese EGS. These problems in the development of EGS reservoirs cannot be readily solved in Japan because they are intrinsically related to the physical characteristics and tectonic setting of the brittle rock mass. Therefore, we have initiated the Japan Beyond-Brittle Project (JBBP), which will take a multidisciplinary scientific approach, including geology, geochemistry, geophysics, water-rock interactions, rock mechanics, seismology, drilling technology, well-logging technology, and reservoir engineering. The science and technology required for the creation and control of geothermal reservoirs in superheated rocks in the ductile zone is at the frontier of modern research in most of the related disciplines. Solutions to the associated problems will not easily be found without international collaboration among researchers and engineers. For this reason, in March, 2013 we held a five-day ICDP-supported workshop in Japan to review and discuss various scientific and technological issues related to the JBBP. Throughout the discussions at the workshop on characteristics of the beyond-brittle rock mass and creation and control of EGS reservoirs in the ductile zone, it has concluded that there are two end-member reservoir models that should be considered (Fig. 1). The JBBP reservoir type-1 would be created near the top of the brittle-ductile transition (BDT) and connected to pre-existing hydrothermal systems, which would increase productivity and provide sustainability. The JBBP reservoir type-2 would be hydraulically or thermally created beyond the BDT, where pre-existing fractures are less permeable, and would be hydraulically isolated from the hydrothermal system. Discussions on exploration/monitoring of the BDT rock mass and JBBP reservoirs, and engineering development have been also made in the workshop. We finally identified scientific/technological challenges for the JBBP and established roadmap and implementation plan. The workshop report is available at http://jbbp.kankyo.tohoku.ac.jp/jbbp Conceptual model of the JBBP

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…

Cicada-inspired cell-instructive nanopatterned arrays

NASA Astrophysics Data System (ADS)

Diu, Ting; Faruqui, Nilofar; Sjöström, Terje; Lamarre, Baptiste; Jenkinson, Howard F.; Su, Bo; Ryadnov, Maxim G.

2014-11-01

Biocompatible surfaces hold key to a variety of biomedical problems that are directly related to the competition between host-tissue cell integration and bacterial colonisation. A saving solution to this is seen in the ability of cells to uniquely respond to physical cues on such surfaces thus prompting the search for cell-instructive nanoscale patterns. Here we introduce a generic rationale engineered into biocompatible, titanium, substrates to differentiate cell responses. The rationale is inspired by cicada wing surfaces that display bactericidal nanopillar patterns. The surfaces engineered in this study are titania (TiO2) nanowire arrays that are selectively bactericidal against motile bacteria, while capable of guiding mammalian cell proliferation according to the type of the array. The concept holds promise for clinically relevant materials capable of differential physico-mechanical responses to cellular adhesion.

Cicada-inspired cell-instructive nanopatterned arrays.

PubMed

Diu, Ting; Faruqui, Nilofar; Sjöström, Terje; Lamarre, Baptiste; Jenkinson, Howard F; Su, Bo; Ryadnov, Maxim G

2014-11-20

Biocompatible surfaces hold key to a variety of biomedical problems that are directly related to the competition between host-tissue cell integration and bacterial colonisation. A saving solution to this is seen in the ability of cells to uniquely respond to physical cues on such surfaces thus prompting the search for cell-instructive nanoscale patterns. Here we introduce a generic rationale engineered into biocompatible, titanium, substrates to differentiate cell responses. The rationale is inspired by cicada wing surfaces that display bactericidal nanopillar patterns. The surfaces engineered in this study are titania (TiO2) nanowire arrays that are selectively bactericidal against motile bacteria, while capable of guiding mammalian cell proliferation according to the type of the array. The concept holds promise for clinically relevant materials capable of differential physico-mechanical responses to cellular adhesion.

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.

Composite materials. Volume 3 - Engineering applications of composites. Volume 4 - Metallic matrix composites. Volume 8 - Structural design and analysis, Part 2

NASA Technical Reports Server (NTRS)

Noton, B. R. (Editor); Kreider, K. G.; Chamis, C. C.

1974-01-01

This volume discusses a vaety of applications of both low- and high-cost composite materials in a number of selected engineering fields. The text stresses the use of fiber-reinforced composites, along with interesting material systems used in the electrical and nuclear industries. As to technology transfer, a similarity is noted between many of the reasons responsible for the utilization of composites and those problems requiring urgent solution, such as mechanized fabrication processes and design for production. Features topics include road transportation, rail transportation, civil aircraft, space vehicles, builing industry, chemical plants, and appliances and equipment. The laminate orientation code devised by Air Force materials laboratory is included. Individual items are announced in this issue.

Collaborative-Large scale Engineering Assessment Networks for Environmental Research: The Overview

NASA Astrophysics Data System (ADS)

Moo-Young, H.

2004-05-01

A networked infrastructure for engineering solutions and policy alternatives is necessary to assess, manage, and protect complex, anthropogenic ally stressed environmental resources effectively. Reductionist and discrete disciplinary methodologies are no longer adequate to evaluate and model complex environmental systems and anthropogenic stresses. While the reductonist approach provides important information regarding individual mechanisms, it cannot provide complete information about how multiple processes are related. Therefore, it is not possible to make accurate predictions about system responses to engineering interventions and the effectiveness of policy options. For example, experts cannot agree on best management strategies for contaminated sediments in riverine and estuarine systems. This is due, in part to the fact that existing models do not accurately capture integrated system dynamics. In addition, infrastructure is not available for investigators to exchange and archive data, to collaborate on new investigative methods, and to synthesize these results to develop engineering solutions and policy alternatives. Our vision for the future is to create a network comprising field facilities and a collaboration of engineers, scientists, policy makers, and community groups. This will allow integration across disciplines, across different temporal and spatial scales, surface and subsurface geographies, and air sheds and watersheds. Benefits include fast response to changes in system health, real-time decision making, and continuous data collection that can be used to anticipate future problems, and to develop sound engineering solutions and management decisions. CLEANER encompasses four general aspects: 1) A Network of environmental field facilities instrumented for the acquisition and analysis of environmental data; 2) A Virtual Repository of Data and information technology for engineering modeling, analysis and visualization of data, i.e. an environmental cyber-infrastructure; 3) A Mechanism for multidisciplinary research and education activities designed to exploit the output of the instrumented sites and networked information technology, to formulate engineering and policy options directed toward the protection, remediation, and restoration of stressed environments and sustainability of environmental resources; and 4) A Collaboration among engineers, natural and social scientists, educators, policy makers, industry, non-governmental organizations, the public, and other stakeholders.

Problem-Based Learning in Engineering Ethics Courses

ERIC Educational Resources Information Center

Kirkman, Robert

2016-01-01

I describe the first stages of a process of design research in which I employ problem-based learning in a course in engineering ethics, which fulfills a requirement for students in engineering degree programs. The aim of the course is to foster development of particular cognitive skills contributing to moral imagination, a capacity to notice,…

Generating Alternative Engineering Designs by Integrating Desktop VR with Genetic Algorithms

ERIC Educational Resources Information Center

Chandramouli, Magesh; Bertoline, Gary; Connolly, Patrick

2009-01-01

This study proposes an innovative solution to the problem of multiobjective engineering design optimization by integrating desktop VR with genetic computing. Although, this study considers the case of construction design as an example to illustrate the framework, this method can very much be extended to other engineering design problems as well.…

Efficacy of an Online Resource for Teaching Interpersonal Problem Solving Skills to Women Graduate Students in Engineering

ERIC Educational Resources Information Center

Bekki, Jennifer M.; Bernstein, Bianca; Fabert, Natalie; Gildar, Natalie; Way, Amy

2014-01-01

Interpersonal problem solving skills allow engineers to prevent interpersonal difficulties more effectively and to manage conflict, both of which are critical to successful participation on teams. This research provides evidence that the "Career"WISE online learning environment can improve those skills among women in engineering graduate…

Introducing the "Decider" Design Process

ERIC Educational Resources Information Center

Prasa, Anthony R., Jr.; Del Guercio, Ryan

2016-01-01

Engineers are faced with solving important problems every day and must follow a step-by-step design process to arrive at solutions. Students who are taught an effective design process to apply to engineering projects begin to see problems as an engineer would, consider all ideas, and arrive at the best solution. Using an effective design process…

Design, Test, Redesign: Simulation in Technology, Engineering, and Design Education Classrooms

ERIC Educational Resources Information Center

Swinson, Ronnie; Clark, Aaron C.; Ernst, Jeremy V.; Sutton, Kevin

2016-01-01

Today's engineers, designers, and technologists are often thrust into the role of problem solver, from the initial design phase of a product or process all the way to final development. Many engineers in manufacturing environments are tasked with solving problems and continuously improving processes to enhance company profitability, efficiency,…

Experimental research on the Stirling engine

NASA Technical Reports Server (NTRS)

Ishizaki, Y.; Tani, Y.; Haramura, N.

1982-01-01

Experiments on Stirling engines of the 50 KW class were conducted to clarify the characteristics of the engine and its problems. The problems involve durability of the high temperature heat exchanger which is exposed to high flame temperatures above 1600 C, thermal distortion and high temperature corrosion of the devices near combustion, and of the preheater.

Library Systems Engineering: An Introduction.

ERIC Educational Resources Information Center

Buckland, Michael K.; Tolliver, Don L.

The application of systems engineering and operations research to the problems of libraries has developed quite strongly during the past five years. The purpose of this paper is to draw attention to this relatively new area. There are serious problems of applying systems engineering to libraries. This is to be expected in the case of a…

Gender and Participation in an Engineering Problem-Based Learning Environment

ERIC Educational Resources Information Center

Hirshfield, Laura; Koretsky, Milo D.

2018-01-01

The use of problem-based learning (PBL) is gaining attention in the engineering classroom as a way to help students synthesize foundational knowledge and to better prepare students for practice. In this work, we study the discourse interactions between 27 student teams and two instructors in an engineering PBL environment to analyze how…

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…

Pressurized-water reactor internals aging degradation study. Phase 1

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

Luk, K.H.

1993-09-01

This report documents the results of a Phase I study on the effects of aging degradations on pr internals. Primary stressers for internals an generated by the primary coolant flow in the they include unsteady hydrodynamic forces and pump-generated pressure pulsations. Other stressors are applied loads, manufacturing processes, impurities in the coolant and exposures to fast neutron fluxes. A survey of reported aging-related failure information indicates that fatigue, stress corrosion cracking (SCC) and mechanical wear are the three major aging-related degradation mechanisms for PWR internals. Significant reported failures include thermal shield flow-induced vibration problems, SCC in guide tube support pinsmore » and core support structure bolts, fatigue-induced core baffle water-jet impingement problems and excess wear in flux thimbles. Many of the reported problems have been resolved by accepted engineering practices. Uncertainties remain in the assessment of long-term neutron irradiation effects and environmental factors in high-cycle fatigue failures. Reactor internals are examined by visual inspections and the technique is access limited. Improved inspection methods, especially one with an early failure detection capability, can enhance the safety and efficiency of reactor operations.« less

A comparative analysis of numerical approaches to the mechanics of elastic sheets

NASA Astrophysics Data System (ADS)

Taylor, Michael; Davidovitch, Benny; Qiu, Zhanlong; Bertoldi, Katia

2015-06-01

Numerically simulating deformations in thin elastic sheets is a challenging problem in computational mechanics due to destabilizing compressive stresses that result in wrinkling. Determining the location, structure, and evolution of wrinkles in these problems has important implications in design and is an area of increasing interest in the fields of physics and engineering. In this work, several numerical approaches previously proposed to model equilibrium deformations in thin elastic sheets are compared. These include standard finite element-based static post-buckling approaches as well as a recently proposed method based on dynamic relaxation, which are applied to the problem of an annular sheet with opposed tractions where wrinkling is a key feature. Numerical solutions are compared to analytic predictions of the ground state, enabling a quantitative evaluation of the predictive power of the various methods. Results indicate that static finite element approaches produce local minima that are highly sensitive to initial imperfections, relying on a priori knowledge of the equilibrium wrinkling pattern to generate optimal results. In contrast, dynamic relaxation is much less sensitive to initial imperfections and can generate low-energy solutions for a wide variety of loading conditions without requiring knowledge of the equilibrium solution beforehand.

Middle School Engineering Problem Solving Using Traditional vs. E-PBL Module Instruction

ERIC Educational Resources Information Center

Baele, Loren C.

2017-01-01

This multiple methods (Denzin, 1978) study investigated two instructional approaches, traditional module and electronic Problem-Based Learning instruction (e-PBL), used within a middle school engineering classroom focused on the variables of engagement, content knowledge, student self-assessment and teacher assessment of problem solving solutions.…

Automatic building information model query generation

DOE PAGES

Jiang, Yufei; Yu, Nan; Ming, Jiang; ...

2015-12-01

Energy efficient building design and construction calls for extensive collaboration between different subfields of the Architecture, Engineering and Construction (AEC) community. Performing building design and construction engineering raises challenges on data integration and software interoperability. Using Building Information Modeling (BIM) data hub to host and integrate building models is a promising solution to address those challenges, which can ease building design information management. However, the partial model query mechanism of current BIM data hub collaboration model has several limitations, which prevents designers and engineers to take advantage of BIM. To address this problem, we propose a general and effective approachmore » to generate query code based on a Model View Definition (MVD). This approach is demonstrated through a software prototype called QueryGenerator. In conclusion, by demonstrating a case study using multi-zone air flow analysis, we show how our approach and tool can help domain experts to use BIM to drive building design with less labour and lower overhead cost.« less

Automatic building information model query generation

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

Jiang, Yufei; Yu, Nan; Ming, Jiang

Energy efficient building design and construction calls for extensive collaboration between different subfields of the Architecture, Engineering and Construction (AEC) community. Performing building design and construction engineering raises challenges on data integration and software interoperability. Using Building Information Modeling (BIM) data hub to host and integrate building models is a promising solution to address those challenges, which can ease building design information management. However, the partial model query mechanism of current BIM data hub collaboration model has several limitations, which prevents designers and engineers to take advantage of BIM. To address this problem, we propose a general and effective approachmore » to generate query code based on a Model View Definition (MVD). This approach is demonstrated through a software prototype called QueryGenerator. In conclusion, by demonstrating a case study using multi-zone air flow analysis, we show how our approach and tool can help domain experts to use BIM to drive building design with less labour and lower overhead cost.« less

Photolithography diagnostic expert systems: a systematic approach to problem solving in a wafer fabrication facility

NASA Astrophysics Data System (ADS)

Weatherwax Scott, Caroline; Tsareff, Christopher R.

1990-06-01

One of the main goals of process engineering in the semiconductor industry is to improve wafer fabrication productivity and throughput. Engineers must work continuously toward this goal in addition to performing sustaining and development tasks. To accomplish these objectives, managers must make efficient use of engineering resources. One of the tools being used to improve efficiency is the diagnostic expert system. Expert systems are knowledge based computer programs designed to lead the user through the analysis and solution of a problem. Several photolithography diagnostic expert systems have been implemented at the Hughes Technology Center to provide a systematic approach to process problem solving. This systematic approach was achieved by documenting cause and effect analyses for a wide variety of processing problems. This knowledge was organized in the form of IF-THEN rules, a common structure for knowledge representation in expert system technology. These rules form the knowledge base of the expert system which is stored in the computer. The systems also include the problem solving methodology used by the expert when addressing a problem in his area of expertise. Operators now use the expert systems to solve many process problems without engineering assistance. The systems also facilitate the collection of appropriate data to assist engineering in solving unanticipated problems. Currently, several expert systems have been implemented to cover all aspects of the photolithography process. The systems, which have been in use for over a year, include wafer surface preparation (HMDS), photoresist coat and softbake, align and expose on a wafer stepper, and develop inspection. These systems are part of a plan to implement an expert system diagnostic environment throughout the wafer fabrication facility. In this paper, the systems' construction is described, including knowledge acquisition, rule construction, knowledge refinement, testing, and evaluation. The roles played by the process engineering expert and the knowledge engineer are discussed. The features of the systems are shown, particularly the interactive quality of the consultations and the ease of system use.

Test results and description of a 1-kW free-piston Stirling engine with a dashpot load

NASA Technical Reports Server (NTRS)

Schreiber, J.

1983-01-01

A 1 kW (1.33 hp) single cylinder free piston Stirling engine was installed in the test facilities at the Lewis laboratory. The engine was designed specifically for research of the dynamics of its operation. A more complete description of the engine and its instrumentation is provided in a prior NASA paper TM-82999 by J. G. Schreiber. Initial tests at Lewis showed the power level and efficiency of the engine to be below design level. Tests were performed to help determine the specific problems in the engine causing the below design level performance. Modifications to engine hardware and to the facility where performed in an effort to bring the power output and efficiency to their design values. As finally configured the engine generated more than 1250 watts of output power at an engine efficiency greater than 32 percent. This report presents the tests performed to help determine the specific problems, the results if the problem was eliminated, the fix performed to the hardware, and the test results after the engine was tested. In cases where the fix did not cause the anticipated effects, a possible explanation is given.

Optimal Sensor Layouts in Underwater Locomotory Systems

NASA Astrophysics Data System (ADS)

Colvert, Brendan; Kanso, Eva

2015-11-01

Retrieving and understanding global flow characteristics from local sensory measurements is a challenging but extremely relevant problem in fields such as defense, robotics, and biomimetics. It is an inverse problem in that the goal is to translate local information into global flow properties. In this talk we present techniques for optimization of sensory layouts within the context of an idealized underwater locomotory system. Using techniques from fluid mechanics and control theory, we show that, under certain conditions, local measurements can inform the submerged body about its orientation relative to the ambient flow, and allow it to recognize local properties of shear flows. We conclude by commenting on the relevance of these findings to underwater navigation in engineered systems and live organisms.

An exact stiffness theory for unidirectional xFRP composites

NASA Astrophysics Data System (ADS)

Klasztorny, M.; Konderla, P.; Piekarski, R.

2009-01-01

UD xFRP composites, i.e., isotropic plastics reinforced with long transversely isotropic fibres packed unidirectionally according to the hexagonal scheme are considered. The constituent materials are geometrically and physically linear. The previous formulations of the exact stiffness theory of such composites are revised, and the theory is developed further based on selected boundary-value problems of elasticity theory. The numerical examples presented are focussed on testing the theory with account of previous variants of this theory and experimental values of the effective elastic constants. The authors have pointed out that the exact stiffness theory of UD xFRP composites, with the modifications proposed in our study, will be useful in the engineering practice and in solving the current problems of the mechanics of composite materials.

Solution of the neutronics code dynamic benchmark by finite element method

NASA Astrophysics Data System (ADS)

Avvakumov, A. V.; Vabishchevich, P. N.; Vasilev, A. O.; Strizhov, V. F.

2016-10-01

The objective is to analyze the dynamic benchmark developed by Atomic Energy Research for the verification of best-estimate neutronics codes. The benchmark scenario includes asymmetrical ejection of a control rod in a water-type hexagonal reactor at hot zero power. A simple Doppler feedback mechanism assuming adiabatic fuel temperature heating is proposed. The finite element method on triangular calculation grids is used to solve the three-dimensional neutron kinetics problem. The software has been developed using the engineering and scientific calculation library FEniCS. The matrix spectral problem is solved using the scalable and flexible toolkit SLEPc. The solution accuracy of the dynamic benchmark is analyzed by condensing calculation grid and varying degree of finite elements.

Nonlinear dynamics of mini-satellite respinup by weak internal controllable torques

NASA Astrophysics Data System (ADS)

Somov, Yevgeny

2014-12-01

Contemporary space engineering advanced new problem before theoretical mechanics and motion control theory: a spacecraft directed respinup by the weak restricted control internal forces. The paper presents some results on this problem, which is very actual for energy supply of information mini-satellites (for communication, geodesy, radio- and opto-electronic observation of the Earth et al.) with electro-reaction plasma thrusters and gyro moment cluster based on the reaction wheels or the control moment gyros. The solution achieved is based on the methods for synthesis of nonlinear robust control and on rigorous analytical proof for the required spacecraft rotation stability by Lyapunov function method. These results were verified by a computer simulation of strongly nonlinear oscillatory processes at respinuping of a flexible spacecraft.

Benchmarking Gas Path Diagnostic Methods: A Public Approach

NASA Technical Reports Server (NTRS)

Simon, Donald L.; Bird, Jeff; Davison, Craig; Volponi, Al; Iverson, R. Eugene

2008-01-01

Recent technology reviews have identified the need for objective assessments of engine health management (EHM) technology. The need is two-fold: technology developers require relevant data and problems to design and validate new algorithms and techniques while engine system integrators and operators need practical tools to direct development and then evaluate the effectiveness of proposed solutions. This paper presents a publicly available gas path diagnostic benchmark problem that has been developed by the Propulsion and Power Systems Panel of The Technical Cooperation Program (TTCP) to help address these needs. The problem is coded in MATLAB (The MathWorks, Inc.) and coupled with a non-linear turbofan engine simulation to produce "snap-shot" measurements, with relevant noise levels, as if collected from a fleet of engines over their lifetime of use. Each engine within the fleet will experience unique operating and deterioration profiles, and may encounter randomly occurring relevant gas path faults including sensor, actuator and component faults. The challenge to the EHM community is to develop gas path diagnostic algorithms to reliably perform fault detection and isolation. An example solution to the benchmark problem is provided along with associated evaluation metrics. A plan is presented to disseminate this benchmark problem to the engine health management technical community and invite technology solutions.

Engineering the future with America's high school students

NASA Technical Reports Server (NTRS)

Farrance, M. A.; Jenner, J. W.

1993-01-01

The number of students enrolled in engineering is declining while the need for engineers is increasing. One contributing factor is that most high school students have little or no knowledge about what engineering is, or what engineers do. To teach young students about engineering, engineers need good tools. This paper presents a course of study developed and used by the authors in a junior college course for high school students. Students learned about engineering through independent student projects, in-class problem solving, and use of career information resources. Selected activities from the course can be adapted to teach students about engineering in other settings. Among the most successful techniques were the student research paper assignments, working out a solution to an engineering problem as a class exercise, and the use of technical materials to illustrate engineering concepts and demonstrate 'tools of the trade'.

A multiscale model of distributed fracture and permeability in solids in all-round compression

NASA Astrophysics Data System (ADS)

De Bellis, Maria Laura; Della Vecchia, Gabriele; Ortiz, Michael; Pandolfi, Anna

2017-07-01

We present a microstructural model of permeability in fractured solids, where the fractures are described in terms of recursive families of parallel, equidistant cohesive faults. Faults originate upon the attainment of tensile or shear strength in the undamaged material. Secondary faults may form in a hierarchical organization, creating a complex network of connected fractures that modify the permeability of the solid. The undamaged solid may possess initial porosity and permeability. The particular geometry of the superposed micro-faults lends itself to an explicit analytical quantification of the porosity and permeability of the damaged material. The model is the finite kinematics version of a recently proposed porous material model, applied with success to the simulation of laboratory tests and excavation problems [De Bellis, M. L., Della Vecchia, G., Ortiz, M., Pandolfi, A., 2016. A linearized porous brittle damage material model with distributed frictional-cohesive faults. Engineering Geology 215, 10-24. Cited By 0. 10.1016/j.enggeo.2016.10.010]. The extension adds over and above the linearized kinematics version for problems characterized by large deformations localized in narrow zones, while the remainder of the solid undergoes small deformations, as typically observed in soil and rock mechanics problems. The approach is particularly appealing as a means of modeling a wide scope of engineering problems, ranging from the prevention of water or gas outburst into underground mines, to the prediction of the integrity of reservoirs for CO2 sequestration or hazardous waste storage, to hydraulic fracturing processes.

Strategies for Limiting Engineers' Potential Liability for Indoor Air Quality Problems.

PubMed

von Oppenfeld, Rolf R; Freeze, Mark E; Sabo, Sean M

1998-10-01

Engineers face indoor air quality (IAQ) issues at the design phase of building construction as well as during the investigation and mitigation of potential indoor air pollution problems during building operation. IAQ issues that can be identified are "building-related illnesses" that may include problems of volatile organic compounds (VOCs). IAQ issues that cannot be identified are termed "sick building syndrome." Frequently, microorganism-caused illnesses are difficult to confirm. Engineers who provide professional services that directly or indirectly impact IAQ face significant potential liability to clients and third parties when performing these duties. Potential theories supporting liability claims for IAQ problems against engineers include breach of contract and various common law tort theories such as negligence and negligent misrepresentation. Furthermore, an increasing number of federal, state, and local regulations affect IAQ issues and can directly increase the potential liability of engineers. A duty to disclose potential or actual air quality concerns to third parties may apply for engineers in given circumstances. Such a duty may arise from judicial precedent, the Model Guide for Professional Conduct for Engineers, or the Code of Ethics for Engineers. Practical strategies engineers can use to protect themselves from liability include regular training and continuing education in relevant regulatory, scientific, and case law developments; detailed documentation and recordkeeping practices; adequate insurance coverage; contractual indemnity clauses; contractual provisions limiting liability to the scope of work performed; and contractual provisions limiting the extent of liability for engineers' negligence. Furthermore, through the proper use of building materials and construction techniques, an engineer or other design professional can effectively limit the potential for IAQ liability.

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...

The Institute of Biological Engineering 2013 Annual Conference

DTIC Science & Technology

2014-10-30

of Bioengineering University of Washington Presentation: Peptide-Based materials for Drug Delivery Dr. Ya-Ping Sun (Supported by the Grant) Frank...Professor of Biomedical Engineering and Mechanical Engineering and Materials Science Duke University Presentation: Acoustic Microfluidics and New...Triangle Materials Research Science and Engineering Center, Department of Biomedical Engineering, Duke University, Department of Mechanical Engineering

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…