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

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

Berg, Thomas A.; Disney, Richard K.

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

Design, Materials, and Mechanobiology of Biodegradable Scaffolds for Bone Tissue Engineering

PubMed Central

Velasco, Marco A.; Narváez-Tovar, Carlos A.; Garzón-Alvarado, Diego A.

2015-01-01

A review about design, manufacture, and mechanobiology of biodegradable scaffolds for bone tissue engineering is given. First, fundamental aspects about bone tissue engineering and considerations related to scaffold design are established. Second, issues related to scaffold biomaterials and manufacturing processes are discussed. Finally, mechanobiology of bone tissue and computational models developed for simulating how bone healing occurs inside a scaffold are described. PMID:25883972

Green engineering education through a U.S. EPA/academia collaboration.

PubMed

Shonnard, David R; Allen, David T; Nguyen, Nhan; Austin, Sharon Weil; Hesketh, Robert

2003-12-01

The need to use resources efficiently and reduce environmental impacts of industrial products and processes is becoming increasingly important in engineering design; therefore, green engineering principles are gaining prominence within engineering education. This paper describes a general framework for incorporating green engineering design principles into engineering curricula, with specific examples for chemical engineering. The framework for teaching green engineering discussed in this paper mirrors the 12 Principles of Green Engineering proposed by Anastas and Zimmerman (Environ. Sci. Technol. 2003, 37, 94A-101A), especially in methods for estimating the hazardous nature of chemicals, strategies for pollution prevention, and approaches leading to efficient energy and material utilization. The key elements in green engineering education, which enlarge the "box" for engineering design, are environmental literacy, environmentally conscious design, and beyond-the-plant boundary considerations.

Turbine Engine Testing.

DTIC Science & Technology

1981-01-01

per-rev, ring weighting factor, etc.) and with compression system design . A detailed description of the SAE methodology is provided in Ref. 1...offers insights into the practical application of experimental aeromechanical procedures and establishes the process of valid design assessment, avoiding...considerations given to the total engine system. Design Verification in the Experimental Laboratory Certain key parameters are influencing the design of modern

Human Factors Engineering. Part 2. HEDGE (Human Factors Engineering Data Guide for Evaluation)

DTIC Science & Technology

1983-11-30

Use.Condit ions 0 7ý est Item ComoentsTask Categories EPurposes 2 ;c . INDEX TO THE INDEX MAN/ITEM TASK SHEET DETAILED DESIGN CONSIDERATION The purpose of...The use of these materials, in addition to standard Task and Design Checklists and Questionnaires, will enable you to tailor your FIFE subtest to a...specific Con item. The These materials have been prepared especially for you: I. They are intended to support test engineers not design engineers. 2

Supersonic combustion engine testbed, heat lightning

NASA Technical Reports Server (NTRS)

Hoying, D.; Kelble, C.; Langenbahn, A.; Stahl, M.; Tincher, M.; Walsh, M.; Wisler, S.

1990-01-01

The design of a supersonic combustion engine testbed (SCET) aircraft is presented. The hypersonic waverider will utilize both supersonic combustion ramjet (SCRAMjet) and turbofan-ramjet engines. The waverider concept, system integration, electrical power, weight analysis, cockpit, landing skids, and configuration modeling are addressed in the configuration considerations. The subsonic, supersonic and hypersonic aerodynamics are presented along with the aerodynamic stability and landing analysis of the aircraft. The propulsion design considerations include: engine selection, turbofan ramjet inlets, SCRAMjet inlets and the SCRAMjet diffuser. The cooling requirements and system are covered along with the topics of materials and the hydrogen fuel tanks and insulation system. A cost analysis is presented and the appendices include: information about the subsonic wind tunnel test, shock expansion calculations, and an aerodynamic heat flux program.

TMF design considerations in turbine airfoils of advanced turbine engines

NASA Astrophysics Data System (ADS)

Date, C. G.; Zamrik, S. Y.; Adams, J. H.; Frani, N. E.

A review of thermal-mechanicalfatigue (TMF) in advanced turbine engines is presented. The review includes examples of typical thermal-mechnical loadings encountered in the design of hot section blades and vanes. Specific issues related to TMF behavior are presented and the associated impact on component life analysis and design is discussed.

Hydrogel scaffolds for tissue engineering: Progress and challenges

PubMed Central

El-Sherbiny, Ibrahim M.; Yacoub, Magdi H.

2013-01-01

Designing of biologically active scaffolds with optimal characteristics is one of the key factors for successful tissue engineering. Recently, hydrogels have received a considerable interest as leading candidates for engineered tissue scaffolds due to their unique compositional and structural similarities to the natural extracellular matrix, in addition to their desirable framework for cellular proliferation and survival. More recently, the ability to control the shape, porosity, surface morphology, and size of hydrogel scaffolds has created new opportunities to overcome various challenges in tissue engineering such as vascularization, tissue architecture and simultaneous seeding of multiple cells. This review provides an overview of the different types of hydrogels, the approaches that can be used to fabricate hydrogel matrices with specific features and the recent applications of hydrogels in tissue engineering. Special attention was given to the various design considerations for an efficient hydrogel scaffold in tissue engineering. Also, the challenges associated with the use of hydrogel scaffolds were described. PMID:24689032

Program For Optimization Of Nuclear Rocket Engines

NASA Technical Reports Server (NTRS)

Plebuch, R. K.; Mcdougall, J. K.; Ridolphi, F.; Walton, James T.

1994-01-01

NOP is versatile digital-computer program devoloped for parametric analysis of beryllium-reflected, graphite-moderated nuclear rocket engines. Facilitates analysis of performance of engine with respect to such considerations as specific impulse, engine power, type of engine cycle, and engine-design constraints arising from complications of fuel loading and internal gradients of temperature. Predicts minimum weight for specified performance.

Phase change materials handbook

NASA Technical Reports Server (NTRS)

Hale, D. V.; Hoover, M. J.; Oneill, M. J.

1971-01-01

This handbook is intended to provide theory and data needed by the thermal design engineer to bridge the gap between research achievements and actual flight systems, within the limits of the current state of the art of phase change materials (PCM) technology. The relationship between PCM and more conventional thermal control techniques is described and numerous space and terrestrial applications of PCM are discussed. Material properties of the most promising PCMs are provided; the purposes and use of metallic filler materials in PCM composites are presented; and material compatibility considerations relevant to PCM design are included. The engineering considerations of PCM design are described, especially those pertaining to the thermodynamic and heat transfer phenomena peculiar to PCM design. Methods of obtaining data not currently available are presented. The special problems encountered in the space environment are described. Computational tools useful to the designer are discussed. In summary, each aspect of the PCM problem important to the design engineer is covered to the extent allowed by the scope of this effort and the state of the art.

Infusing Engineering Concepts: Teaching Engineering Design

ERIC Educational Resources Information Center

Daugherty, Jenny

2012-01-01

Engineering has gained considerable traction in many K-12 schools. However, there are several obstacles or challenges to an effective approach that leads to student learning. Questions such as where engineering best fits in the curriculum; how to include it authentically and appropriately; toward what educational end; and how best to prepare…

The devil that we know: lead (Pb) replacement policies under conditions of scientific uncertainty

NASA Technical Reports Server (NTRS)

Ogunseitan, Dele; Schoenung, Julie; Saphores, Jean-Daniel; Shapiro, Andrew; Bhuie, Amrit; Kang, Hai-Yong; Nixon, Hilary; Stein, Antionette

2003-01-01

Engineering and economic considerations are typical driving forces behind the selection of specific chemicals used in the manufacture of consumer products. Only recently has post-consumer environmental impact become part of the major considerations during the initial phases of product design. Therefore, reactive, rather than proactive strategies have dominated the consideration of environmental and health issues in product design.

On designing low pressure loss working spaces for a planar Stirling micromachine

NASA Astrophysics Data System (ADS)

Hachey, M.-A.; Léveillé, É.; Fréchette, L. G.; Formosa, F.

2015-12-01

In this paper, research was undertaken with the objective to design low pressure loss working spaces for a Stirling cycle micro heat engine operating from low temperature waste heat. This planar free-piston heat engine is anticipated to operate at the kHz level with mm3 displacement. Given the resonant nature of the free-piston configuration, the complexity of its working gas’ flow geometry and its projected high operating frequency, flow analysis is relatively complex. Design considerations were thus based on fast prototyping and experimentation. Results show that geometrical features, such as a sharp 90° corner between the regenerator and working spaces, are strong contributors to pressure losses. This research culminated into a promising revised working space configuration for engine start-up, as it considerably reduced total pressure losses, more than 80% at Re = 700, from the original design.

Preliminary design of turbopumps and related machinery

NASA Technical Reports Server (NTRS)

Wislicenus, George F.

1986-01-01

Pumps used in large liquid-fuel rocket engines are examined. The term preliminary design denotes the initial, creative phases of design, where the general shape and characteristics of the machine are determined. This compendium is intended to provide the design engineer responsible for these initial phases with a physical understanding and background knowledge of the numerous special fields involved in the design process. Primary attention is directed to the pumping part of the turbopump and hence is concerned with essentially incompressible fluids. However, compressible flow principles are developed. As much as possible, the simplicity and reliability of incompressible flow considerations are retained by treating the mechanics of compressible fluids as a departure from the theory of incompressible fluids. Five areas are discussed: a survey of the field of turbomachinery in dimensionless form; the theoretical principles of the hydrodynamic design of turbomachinery; the hydrodynamic and gas dynamic design of axial flow turbomachinery; the hydrodynamic and gas dynamic design of radial and mixed flow turbomachinery; and some mechanical design considerations of turbomachinery. Theoretical considerations are presented with a relatively elementary mathematical treatment.

46 CFR 116.340 - Alternate design considerations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... ARRANGEMENT Hull Structure § 116.340 Alternate design considerations. The Commanding Officer, Marine Safety... does not meet the requirements of § 116.300, if it is shown by systematic analysis based on engineering principles that the vessel structure provides adequate safety and strength. An owner seeking approval of an...

46 CFR 116.340 - Alternate design considerations.

Code of Federal Regulations, 2011 CFR

2011-10-01

... ARRANGEMENT Hull Structure § 116.340 Alternate design considerations. The Commanding Officer, Marine Safety... does not meet the requirements of § 116.300, if it is shown by systematic analysis based on engineering principles that the vessel structure provides adequate safety and strength. An owner seeking approval of an...

46 CFR 116.340 - Alternate design considerations.

Code of Federal Regulations, 2013 CFR

2013-10-01

... ARRANGEMENT Hull Structure § 116.340 Alternate design considerations. The Commanding Officer, Marine Safety... does not meet the requirements of § 116.300, if it is shown by systematic analysis based on engineering principles that the vessel structure provides adequate safety and strength. An owner seeking approval of an...

Ceramic port shields cast in an iron engine head

NASA Technical Reports Server (NTRS)

Hakim, Nabil S.; Groeneweg, Mark A.

1989-01-01

Silicon nitride exhaust and intake port shields have been successfully cast into a gray iron cylinder head of a heavy duty diesel single cylinder research engine. Careful design considerations, finite element, and probability of survival analyses indicated viability of the design. Foundry experience, NDE, and failure investigations are reported.

Engine System Loads Development for the Fastrac 60K Flight Engine

NASA Technical Reports Server (NTRS)

Frady, Greg; Christensen, Eric R.; Mims, Katherine; Harris, Don; Parks, Russell; Brunty, Joseph

2000-01-01

Early implementation of structural dynamics finite element analyses for calculation of design loads is considered common design practice for high volume manufacturing industries such as automotive and aeronautical industries. However, with the rarity of rocket engine development programs starts, these tools are relatively new to the design of rocket engines. In the new Fastrac engine program, the focus has been to reduce the cost to weight ratio; current structural dynamics analysis practices were tailored in order to meet both production and structural design goals. Perturbation of rocket engine design parameters resulted in a number of Fastrac load cycles necessary to characterize the impact due to mass and stiffness changes. Evolution of loads and load extraction methodologies, parametric considerations and a discussion of load path sensitivities are discussed.

An engineering perspective on 3D printed personalized scaffolds for tracheal suspension technique

PubMed Central

An, Jia

2016-01-01

3D printing is a large family of many distinct technologies covering a wide range of topics. From an engineering point of view, there should be considerations for selection of design, material, and process when using 3D printing for surgical technique innovation such as personalized scaffolds. Moreover, cost should also be considered if there are equally effective alternatives to the innovation. Furthermore, engineering considerations and options should be clearly communicated and readily available to surgeons for advancement in future. PMID:28149624

An engineering perspective on 3D printed personalized scaffolds for tracheal suspension technique.

PubMed

An, Jia; Chua, Chee Kai

2016-12-01

3D printing is a large family of many distinct technologies covering a wide range of topics. From an engineering point of view, there should be considerations for selection of design, material, and process when using 3D printing for surgical technique innovation such as personalized scaffolds. Moreover, cost should also be considered if there are equally effective alternatives to the innovation. Furthermore, engineering considerations and options should be clearly communicated and readily available to surgeons for advancement in future.

QCGAT aircraft/engine design for reduced noise and emissions

NASA Technical Reports Server (NTRS)

Lanson, L.; Terrill, K. M.

1980-01-01

The high bypass ratio QCGAT engine played an important role in shaping the aircraft design. The aircraft which evolved is a sleek, advanced design, six-place aircraft with 3538 kg (7,800 lb) maximum gross weight. It offers a 2778 kilometer (1500 nautical mile) range with cruise speed of 0.5 Mach number and will take-off and land on the vast majority of general aviation airfields. Advanced features include broad application of composite materials and a supercritical wing design with winglets. Full-span fowler flaps were introduced to improve landing capability. Engines are fuselage-mounted with inlets over the wing to provide shielding of fan noise by the wing surfaces. The design objectives, noise, and emission considerations, engine cycle and engine description are discussed as well as specific design features.

Operating experiences with rotary air-to-air heat exchangers: hospitals, schools, nursing homes, swimming pools

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

Pearson, R.J.

1976-01-01

Systems utilizing rotary air-to-air heat exchangers are discussed. Basic considerations of use (fresh air requirements, system configurations, cost considerations), typical system layout/design considerations, and operating observations by engineers, staff and maintenance personnel are described.

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

ERIC Educational Resources Information Center

Anderson, W. F.; And Others

1985-01-01

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

Energy efficient engine: Flight propulsion system preliminary analysis and design

NASA Technical Reports Server (NTRS)

Johnston, R. P.; Beitler, R. S.; Bobinger, R. O.; Broman, C. L.; Gravitt, R. D.; Heineke, H.; Holloway, P. R.; Klem, J. S.; Nash, D. O.; Ortiz, P.

1980-01-01

The characteristics of an advanced flight propulsion system (FPS), suitable for introduction in the late 1980's to early 1990's, was more fully defined. It was determined that all goals for efficiency, environmental considerations, and economics could be met or exceeded with the possible exception of NOx emission. In evaluating the FPS, all aspects were considered including component design, performance, weight, initial cost, maintenance cost, engine system integration (including nacelle), and aircraft integration considerations. The current FPS installed specific fuel consumption was reduced 14.2% from that of the CF6-50C reference engine. When integrated into an advanced, subsonic, study transport, the FPS produced a fuel burn savings of 15 to 23% and a direct operating cost reduction of 5 to 12% depending on the mission and study aircraft characteristics relative to the reference engine.

A Perspective on the Clinical Translation of Scaffolds for Tissue Engineering

PubMed Central

Webber, Matthew J.; Khan, Omar F.; Sydlik, Stefanie A.; Tang, Benjamin C.; Langer, Robert

2016-01-01

Scaffolds have been broadly applied within tissue engineering and regenerative medicine to regenerate, replace, or augment diseased or damaged tissue. For a scaffold to perform optimally, several design considerations must be addressed, with an eye toward the eventual form, function, and tissue site. The chemical and mechanical properties of the scaffold must be tuned to optimize the interaction with cells and surrounding tissues. For complex tissue engineering, mass transport limitations, vascularization, and host tissue integration are important considerations. As the tissue architecture to be replaced becomes more complex and hierarchical, scaffold design must also match this complexity to recapitulate a functioning tissue. We outline these design constraints and highlight creative and emerging strategies to overcome limitations and modulate scaffold properties for optimal regeneration. We also highlight some of the most advanced strategies that have seen clinical application and discuss the hurdles that must be overcome for clinical use and commercialization of tissue engineering technologies. Finally, we provide a perspective on the future of scaffolds as a functional contributor to advancing tissue engineering and regenerative medicine. PMID:25201605

A perspective on the clinical translation of scaffolds for tissue engineering.

PubMed

Webber, Matthew J; Khan, Omar F; Sydlik, Stefanie A; Tang, Benjamin C; Langer, Robert

2015-03-01

Scaffolds have been broadly applied within tissue engineering and regenerative medicine to regenerate, replace, or augment diseased or damaged tissue. For a scaffold to perform optimally, several design considerations must be addressed, with an eye toward the eventual form, function, and tissue site. The chemical and mechanical properties of the scaffold must be tuned to optimize the interaction with cells and surrounding tissues. For complex tissue engineering, mass transport limitations, vascularization, and host tissue integration are important considerations. As the tissue architecture to be replaced becomes more complex and hierarchical, scaffold design must also match this complexity to recapitulate a functioning tissue. We outline these design constraints and highlight creative and emerging strategies to overcome limitations and modulate scaffold properties for optimal regeneration. We also highlight some of the most advanced strategies that have seen clinical application and discuss the hurdles that must be overcome for clinical use and commercialization of tissue engineering technologies. Finally, we provide a perspective on the future of scaffolds as a functional contributor to advancing tissue engineering and regenerative medicine.

46 CFR 160.135-7 - Design, construction, and performance of lifeboats.

Code of Federal Regulations, 2013 CFR

2013-10-01

... materials equivalent or superior in strength, design, wet out, and efficiency will be given consideration on.... (8) Starting system batteries. Any battery fitted in a totally enclosed lifeboat must be stored in a... starting battery is required per engine. (9) Exhaust. Engine exhaust must be routed away from bilge and...

46 CFR 160.135-7 - Design, construction, and performance of lifeboats.

Code of Federal Regulations, 2012 CFR

2012-10-01

... materials equivalent or superior in strength, design, wet out, and efficiency will be given consideration on.... (8) Starting system batteries. Any battery fitted in a totally enclosed lifeboat must be stored in a... starting battery is required per engine. (9) Exhaust. Engine exhaust must be routed away from bilge and...

46 CFR 160.135-7 - Design, construction, and performance of lifeboats.

Code of Federal Regulations, 2014 CFR

2014-10-01

... materials equivalent or superior in strength, design, wet out, and efficiency will be given consideration on.... (8) Starting system batteries. Any battery fitted in a totally enclosed lifeboat must be stored in a... starting battery is required per engine. (9) Exhaust. Engine exhaust must be routed away from bilge and...

Collegiality and commerce: The culture of consideration amongst engineers

NASA Astrophysics Data System (ADS)

Nugent, Paul David

This study is a participant observation ethnography of engineering relationships at a defense contracting plant that specializes in the design and manufacture of launch control systems for nuclear submarines. "Consideration" is presented as a unique mode of interaction enabling resource exchange and pivotal in developing and strengthening work relationships. Consideration differs from other modes of exchange such as markets, gift-giving, and charity primarily in that the bestowal of the resource involves little sacrifice. The manner in which consideration is enacted by the engineers, the structural and cultural conditions supporting consideration, and the social and economic consequences of consideration are presented. From these findings it is concluded that consideration is a unique form of economic exchange embedded in concrete relationships that forces us to rethink and extend current conceptualizations of trust, networks, social capital, and friendship in the workplace. The data for the analysis were drawn from twenty interviews and fieldnotes collected and transcribed over a twelve month period. Quotations from the interviews and exerpts from the fieldnotes are included to illustrate claims being made in the analysis as well as to familiarize the reader with the culture developed by engineers and managers in a defense contracting plant.

Systems integrated human engineering on the Navy's rapid acquisition of manufactured parts/test and integration facility

NASA Technical Reports Server (NTRS)

Gallaway, Glen R.

1987-01-01

Human Engineering in many projects is at best a limited support function. In this Navy project the Human Engineering function is an integral component of the systems design and development process. Human Engineering is a member of the systems design organization. This ensures that people considerations are: (1) identified early in the project; (2) accounted for in the specifications; (3) incorporated into the design; and (4) the tested product meets the needs and expectations of the people while meeting the overall systems requirements. The project exemplifies achievements that can be made by the symbiosis between systems designers, engineers and Human Engineering. This approach increases Human Engineering's effectiveness and value to a project because it becomes an accepted, contributing team member. It is an approach to doing Human Engineering that should be considered for most projects. The functional and organizational issues giving this approach strength are described.

Lateral-directional aerodynamic characteristics of light, twin-engine, propeller driven airplanes

NASA Technical Reports Server (NTRS)

Wolowicz, C. H.; Yancey, R. B.

1972-01-01

Analytical procedures and design data for predicting the lateral-directional static and dynamic stability and control characteristics of light, twin engine, propeller driven airplanes for propeller-off and power-on conditions are reported. Although the consideration of power effects is limited to twin engine airplanes, the propeller-off considerations are applicable to single engine airplanes as well. The procedures are applied to a twin engine, propeller driven, semi-low-wing airplane in the clean configuration through the linear lift range. The calculated derivative characteristics are compared with wind tunnel and flight data. Included in the calculated characteristics are the spiral mode, roll mode, and Dutch roll mode over the speed range of the airplane.

Adaptation of Combustion Principles to Aircraft Propulsion. Volume I; Basic Considerations in the Combustion of Hydrocarbon Fuels with Air

NASA Technical Reports Server (NTRS)

Barnett, Henry C (Editor); Hibbard, Robert R (Editor)

1955-01-01

The report summarizes source material on combustion for flight-propulsion engineers. First, several chapters review fundamental processes such as fuel-air mixture preparation, gas flow and mixing, flammability and ignition, flame propagation in both homogenous and heterogenous media, flame stabilization, combustion oscillations, and smoke and carbon formation. The practical significance and the relation of these processes to theory are presented. A second series of chapters describes the observed performance and design problems of engine combustors of the principal types. An attempt is made to interpret performance in terms of the fundamental processes and theories previously reviewed. Third, the design of high-speed combustion systems is discussed. Combustor design principles that can be established from basic considerations and from experience with actual combustors are described. Finally, future requirements for aircraft engine combustion systems are examined.

Performance of Axial-Flow Supersonic Compressor of XJ55-FF-1 Turbojet Engine. III; Over-All Performance of Compressor

NASA Technical Reports Server (NTRS)

Hartmann, Melvin J.; Tysl, Edward R.

1949-01-01

An investigation was conducted to determine the performance characteristics of the rotor and inlet guide vanes used in the axial-flow supersonic compressor of the XJ55-FF-1 turbojet engine. Outlet stators used in the engine were omitted to facilitate study of the supersonic rotor. The extent of the deviation from design performance indicates that the design-shock configuration was not obtained. A maximum pressure ratio of 2.26 was obtained at an equivalent tip speed of 1614 feet per second and an adiabatic efficiency of 0.61. The maximum efficiency obtained was 0.79 at an equivalent tip speed of 801 feet per second and a pressure ratio of 1.29. The performance obtained was considerably below design performance. The effective aerodynamic forces encountered appeared to be large enough to cause considerable damage to the thin aluminum leading edges of the rotor blades.

Energy efficient engine flight propulsion system: Aircraft/engine integration evaluation

NASA Technical Reports Server (NTRS)

Patt, R. F.

1980-01-01

Results of aircraft/engine integration studies conducted on an advanced flight propulsion system are reported. Economic evaluations of the preliminary design are included and indicate that program goals will be met. Installed sfc, DOC, noise, and emissions were evaluated. Aircraft installation considerations and growth were reviewed.

Energy efficient engine flight propulsion system: Aircraft/engine integration evaluation

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

Patt, R.F.

Results of aircraft/engine integration studies conducted on an advanced flight propulsion system are reported. Economic evaluations of the preliminary design are included and indicate that program goals will be met. Installed sfc, DOC, noise, and emissions were evaluated. Aircraft installation considerations and growth were reviewed.

33 CFR 222.2 - Acquisition of lands downstream from spillways for hydrologic safety purposes.

Code of Federal Regulations, 2010 CFR

2010-07-01

... CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE ENGINEERING AND DESIGN § 222.2... agencies having civil works responsibilities. (c) Reference. ER 405-2-150. (d) Discussion. A policy of... that would prevail without the project. General hydrologic engineering considerations are as follows...

Airesearch QCGAT program. [quiet clean general aviation turbofan engines

NASA Technical Reports Server (NTRS)

Heldenbrand, R. W.; Norgren, W. M.

1979-01-01

A model TFE731-1 engine was used as a baseline for the NASA quiet clean general aviation turbofan engine and engine/nacelle program designed to demonstrate the applicability of large turbofan engine technology to small general aviation turbofan engines, and to obtain significant reductions in noise and pollutant emissions while reducing or maintaining fuel consumption levels. All new technology design for rotating parts and all items in the engine and nacelle that contributed to the acoustic and pollution characteristics of the engine system were of flight design, weight, and construction. The major noise, emissions, and performance goals were met. Noise levels estimated for the three FAR Part 36 conditions, are 10 t0 15 ENPdB below FAA requirements; emission values are considerably reduced below that of current technology engines; and the engine performance represents a TSFC improvement of approximately 9 percent over other turbofan engines.

46 CFR 160.156-7 - Design, construction and performance of rescue boats and fast rescue boats.

Code of Federal Regulations, 2014 CFR

2014-10-01

... materials equivalent or superior in strength, design, wet out, and efficiency will be given consideration on... this subpart) meets these requirements for fuel tanks. (9) Starting system batteries. Each battery... the rescue boat has more than one engine, then only one starting battery is required per engine. (10...

46 CFR 160.156-7 - Design, construction and performance of rescue boats and fast rescue boats.

Code of Federal Regulations, 2012 CFR

2012-10-01

... materials equivalent or superior in strength, design, wet out, and efficiency will be given consideration on... this subpart) meets these requirements for fuel tanks. (9) Starting system batteries. Each battery... the rescue boat has more than one engine, then only one starting battery is required per engine. (10...

46 CFR 160.156-7 - Design, construction and performance of rescue boats and fast rescue boats.

Code of Federal Regulations, 2013 CFR

2013-10-01

... materials equivalent or superior in strength, design, wet out, and efficiency will be given consideration on... this subpart) meets these requirements for fuel tanks. (9) Starting system batteries. Each battery... the rescue boat has more than one engine, then only one starting battery is required per engine. (10...

Universal Design: Process, Principles, and Applications

ERIC Educational Resources Information Center

Burgstahler, Sheryl

2009-01-01

Designing any product or environment involves the consideration of many factors, including aesthetics, engineering options, environmental issues, safety concerns, industry standards, and cost. Typically, designers focus their attention on the average user. In contrast, universal design (UD), according to the Center for Universal Design," is…

Engineering Changes in Product Design - A Review

NASA Astrophysics Data System (ADS)

Karthik, K.; Janardhan Reddy, K., Dr

2016-09-01

Changes are fundamental to product development. Engineering changes are unavoidable and can arise at any phase of the product life cycle. The consideration of market requirements, customer/user feedbacks, manufacturing constraints, design innovations etc., turning them into viable products can be accomplished when product change is managed properly. In the early design cycle, informal changes are accepted. However, changes become formal when its complexity and cost increases, and as product matures. To maximize the market shares, manufacturers have to effectively and efficiently manage engineering changes by means of Configuration Control. The paper gives a broad overview about ‘Engineering Change Management’ (ECM) through configuration management and its implications in product design. The aim is to give an idea and understanding about the engineering changes in product design scenario to the new researchers. This paper elaborates the significant aspect of managing the engineering changes and the importance of ECM in a product life cycle.

Human Factors Considerations in System Design

NASA Technical Reports Server (NTRS)

Mitchell, C. M. (Editor); Vanbalen, P. M. (Editor); Moe, K. L. (Editor)

1983-01-01

Human factors considerations in systems design was examined. Human factors in automated command and control, in the efficiency of the human computer interface and system effectiveness are outlined. The following topics are discussed: human factors aspects of control room design; design of interactive systems; human computer dialogue, interaction tasks and techniques; guidelines on ergonomic aspects of control rooms and highly automated environments; system engineering for control by humans; conceptual models of information processing; information display and interaction in real time environments.

Instructional design considerations promoting engineering design self-efficacy

NASA Astrophysics Data System (ADS)

Jackson, Andrew M.

Engineering design activities are frequently included in technology and engineering classrooms. These activities provide an open-ended context for practicing critical thinking, problem solving, creativity, and innovation---collectively part of the 21st Century Skills which are increasingly needed for success in the workplace. Self-efficacy is a perceptual belief that impacts learning and behavior. It has been shown to directly impact each of these 21st Century Skills but its relation to engineering design is only recently being studied. The purpose of this study was to examine how instructional considerations made when implementing engineering design activities might affect student self-efficacy outcomes in a middle school engineering classroom. Student responses to two self-efficacy inventories related to design, the Engineering Design Self-Efficacy Instrument and Creative Thinking Self-Efficacy Inventory, were collected before and after participation in an engineering design curriculum. Students were also answered questions on specific factors of their experience during the curriculum which teachers may exhibit control over: teamwork and feedback. Results were analyzed using Pearson's correlation coefficients, paired and independent t-tests, and structural equation modeling to better understand patterns for self-efficacy beliefs in students. Results suggested that design self-efficacy and creative thinking self-efficacy are significantly correlated, r(1541) = .783, p < .001, and increased following participation in a design curriculum, M diff = 1.32, t(133) = 7.60, p < .001 and Mdiff = 0.79, t(124) = 4.19, p < .001 respectively. Structural models also showed that students perceive team inclusion and feedback as significant contributors to their self-efficacy beliefs, while team diversity was not related to self-efficacy. Separate models for each predictor demonstrated good fit. Recommendations are made based on the corresponding nature of engineering design self-efficacy and creative thinking self-efficacy: strategies encouraging self-efficacy in these domains may be transferrable. Instructors are made aware of the significant impact of classroom strategies for increasing self-efficacy and given specific recommendations related to teamwork and feedback to support students. Finally, although there were weaknesses in the study related to the survey administration, future research opportunities are presented which may build from this work.

Advanced orbit transfer vehicle propulsion system study

NASA Technical Reports Server (NTRS)

Cathcart, J. A.; Cooper, T. W.; Corringrato, R. M.; Cronau, S. T.; Forgie, S. C.; Harder, M. J.; Mcallister, J. G.; Rudman, T. J.; Stoneback, V. W.

1985-01-01

A reuseable orbit transfer vehicle concept was defined and subsequent recommendations for the design criteria of an advanced LO2/LH2 engine were presented. The major characteristics of the vehicle preliminary design include a low lift to drag aerocapture capability, main propulsion system failure criteria of fail operational/fail safe, and either two main engines with an attitude control system for backup or three main engines to meet the failure criteria. A maintenance and servicing approach was also established for the advanced vehicle and engine concepts. Design tradeoff study conclusions were based on the consideration of reliability, performance, life cycle costs, and mission flexibility.

A fault tolerant 80960 engine controller

NASA Technical Reports Server (NTRS)

Reichmuth, D. M.; Gage, M. L.; Paterson, E. S.; Kramer, D. D.

1993-01-01

The paper describes the design of the 80960 Fault Tolerant Engine Controller for the supervision of engine operations, which was designed for the NASA Marshall Space Center. Consideration is given to the major electronic components of the controller, including the engine controller, effectors, and the sensors, as well as to the controller hardware, the controller module and the communications module, and the controller software. The architecture of the controller hardware allows modifications to be made to fit the requirements of any new propulsion systems. Multiple flow diagrams are presented illustrating the controller's operations.

THE DEFINITION AND INTERPRETATION OF TERRESTRIAL ENVIRONMENT DESIGN INPUTS FOR VEHICLE DESIGN CONSIDERATIONS

NASA Technical Reports Server (NTRS)

Johnson, Dale L.; Keller, Vernon W.; Vaughan, William W.

2005-01-01

The description and interpretation of the terrestrial environment (0-90 km altitude) is an important driver of aerospace vehicle structural, control, and thermal system design. NASA is currently in the process of reviewing the meteorological information acquired over the past decade and producing an update to the 1993 Terrestrial Environment Guidelines for Aerospace Vehicle Design and Development handbook. This paper addresses the contents of this updated handbook, with special emphasis on new material being included in the areas of atmospheric thermodynamic models, wind dynamics, atmospheric composition, atmospheric electricity, cloud phenomena, atmospheric extremes, sea state, etc. In addition, the respective engineering design elements will be discussed relative to the importance and influence of terrestrial environment inputs that require consideration and interpretation for design applications. Specific lessons learned that have contributed to the advancements made in the acquisition, interpretation, application and awareness of terrestrial environment inputs for aerospace engineering applications are discussed.

Control Design for a Generic Commercial Aircraft Engine

NASA Technical Reports Server (NTRS)

Csank, Jeffrey; May, Ryan D.

2010-01-01

This paper describes the control algorithms and control design process for a generic commercial aircraft engine simulation of a 40,000 lb thrust class, two spool, high bypass ratio turbofan engine. The aircraft engine is a complex nonlinear system designed to operate over an extreme range of environmental conditions, at temperatures from approximately -60 to 120+ F, and at altitudes from below sea level to 40,000 ft, posing multiple control design constraints. The objective of this paper is to provide the reader an overview of the control design process, design considerations, and justifications as to why the particular architecture and limits have been chosen. The controller architecture contains a gain-scheduled Proportional Integral controller along with logic to protect the aircraft engine from exceeding any limits. Simulation results illustrate that the closed loop system meets the Federal Aviation Administration s thrust response requirements

Engineering study of the rotary-vee engine concept

NASA Technical Reports Server (NTRS)

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

1989-01-01

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

The SCSTPE organic Rankine engine

NASA Technical Reports Server (NTRS)

Boda, F. P.

1980-01-01

The organic Rankine cycle engine under consideration for a solar thermal system being developed is described. Design parameters, method of control, performance and cost data are provided for engine power levels up to 80 kWe; efficiency is shown as a function of turbine inlet temperature in the range of 149 C to 427 C.

33 CFR 222.2 - Acquisition of lands downstream from spillways for hydrologic safety purposes.

Code of Federal Regulations, 2013 CFR

2013-07-01

... CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE ENGINEERING AND DESIGN § 222.2... that would prevail without the project. General hydrologic engineering considerations are as follows... property. (iii) Flood durations are a maximum of 3 hours in urban areas and 24 hours in agricultural areas...

33 CFR 222.2 - Acquisition of lands downstream from spillways for hydrologic safety purposes.

Code of Federal Regulations, 2014 CFR

2014-07-01

... CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE ENGINEERING AND DESIGN § 222.2... that would prevail without the project. General hydrologic engineering considerations are as follows... property. (iii) Flood durations are a maximum of 3 hours in urban areas and 24 hours in agricultural areas...

33 CFR 222.2 - Acquisition of lands downstream from spillways for hydrologic safety purposes.

Code of Federal Regulations, 2012 CFR

2012-07-01

... CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE ENGINEERING AND DESIGN § 222.2... that would prevail without the project. General hydrologic engineering considerations are as follows... property. (iii) Flood durations are a maximum of 3 hours in urban areas and 24 hours in agricultural areas...

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

Skibo, A.

SRNL has considerable experience in designing, engineering, and operating systems for removing iodine-129 (I-129) and ruthenium-106 (Ru-106) from waste streams that are directly analogous to the Advanced Liquid Processing System (ALPS) waste streams. SRNL proposes to provide the technical background and design and engineering support for an improved I-129 and Ru-106 removal system for application to ALPS on the Fukushima Daiichi Nuclear Power Station (NPS).

Proceedings: CE (Corps of Engineers) Workshop on Design and Operation of Selective Withdrawal Intake Structures Held in San Francisco, California on 24-28 June 1985.

DTIC Science & Technology

1986-05-01

design of the outlet works for Warm Springs Dam on Dry Creek in Sonoma County , California, are discussed. Water quality design considerations include both...on Dry Creek, "-’- a right-bank tributary of the Russian River, approximately 14 river miles upstream of their confluence in Sonoma County , California...Dry Creek, Sonoma County , California, are discussed. Water quality design considerations include both temperature and turbidity of discharged water

Universal Design in Postsecondary Education: Process, Principles, and Applications

ERIC Educational Resources Information Center

Burgstahler, Sheryl

2009-01-01

Designing any product or environment involves the consideration of many factors, including aesthetics, engineering options, environmental issues, safety concerns, industry standards, and cost. Typically, designers focus their attention on the average user. In contrast, universal design (UD), according to the Center for Universal Design, "is…

Space Station logistics policy - Risk management from the top down

NASA Technical Reports Server (NTRS)

Paules, Granville; Graham, James L., Jr.

1990-01-01

Considerations are presented in the area of risk management specifically relating to logistics and system supportability. These considerations form a basis for confident application of concurrent engineering principles to a development program, aiming at simultaneous consideration of support and logistics requirements within the engineering process as the system concept and designs develop. It is shown that, by applying such a process, the chances of minimizing program logistics and supportability risk in the long term can be improved. The problem of analyzing and minimizing integrated logistics risk for the Space Station Freedom Program is discussed.

Development and Testing of a High Stability Engine Control (HISTEC) System

NASA Technical Reports Server (NTRS)

Orme, John S.; DeLaat, John C.; Southwick, Robert D.; Gallops, George W.; Doane, Paul M.

1998-01-01

Flight tests were recently completed to demonstrate an inlet-distortion-tolerant engine control system. These flight tests were part of NASA's High Stability Engine Control (HISTEC) program. The objective of the HISTEC program was to design, develop, and flight demonstrate an advanced integrated engine control system that uses measurement-based, real-time estimates of inlet airflow distortion to enhance engine stability. With improved stability and tolerance of inlet airflow distortion, future engine designs may benefit from a reduction in design stall-margin requirements and enhanced reliability, with a corresponding increase in performance and decrease in fuel consumption. This paper describes the HISTEC methodology, presents an aircraft test bed description (including HISTEC-specific modifications) and verification and validation ground tests. Additionally, flight test safety considerations, test plan and technique design and approach, and flight operations are addressed. Some illustrative results are presented to demonstrate the type of analysis and results produced from the flight test program.

Thermal and Environmental Barrier Coatings for Advanced Propulsion Engine Systems

NASA Technical Reports Server (NTRS)

Zhu, Dong-Ming; Miller, Robert A.

2004-01-01

Ceramic thermal and environmental barrier coatings (TEBCs) are used in gas turbine engines to protect engine hot-section components in the harsh combustion environments, and extend component lifetimes. For future high performance engines, the development of advanced ceramic barrier coating systems will allow these coatings to be used to simultaneously increase engine operating temperature and reduce cooling requirements, thereby leading to significant improvements in engine power density and efficiency. In order to meet future engine performance and reliability requirements, the coating systems must be designed with increased high temperature stability, lower thermal conductivity, and improved thermal stress and erosion resistance. In this paper, ceramic coating design and testing considerations will be described for high temperature and high-heat-flux engine applications in hot corrosion and oxidation, erosion, and combustion water vapor environments. Further coating performance and life improvements will be expected by utilizing advanced coating architecture design, composition optimization, and improved processing techniques, in conjunction with modeling and design tools.

Advanced Control Considerations for Turbofan Engine Design

NASA Technical Reports Server (NTRS)

Connolly, Joseph W.; Csank, Jeffrey T.; Chicatelli, Amy

2016-01-01

This paper covers the application of a model-based engine control (MBEC) methodology featuring a self tuning on-board model for an aircraft turbofan engine simulation. The nonlinear engine model is capable of modeling realistic engine performance, allowing for a verification of the advanced control methodology over a wide range of operating points and life cycle conditions. The on-board model is a piece-wise linear model derived from the nonlinear engine model and updated using an optimal tuner Kalman Filter estimation routine, which enables the on-board model to self-tune to account for engine performance variations. MBEC is used here to show how advanced control architectures can improve efficiency during the design phase of a turbofan engine by reducing conservative operability margins. The operability margins that can be reduced, such as stall margin, can expand the engine design space and offer potential for efficiency improvements. Application of MBEC architecture to a nonlinear engine simulation is shown to reduce the thrust specific fuel consumption by approximately 1% over the baseline design, while maintaining safe operation of the engine across the flight envelope.

Engineering study on the rotary-vee engine concept

NASA Technical Reports Server (NTRS)

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

1989-01-01

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

Engine System Loads Analysis Compared to Hot-Fire Data

NASA Technical Reports Server (NTRS)

Frady, Gregory P.; Jennings, John M.; Mims, Katherine; Brunty, Joseph; Christensen, Eric R.; McConnaughey, Paul R. (Technical Monitor)

2002-01-01

Early implementation of structural dynamics finite element analyses for calculation of design loads is considered common design practice for high volume manufacturing industries such as automotive and aeronautical industries. However with the rarity of rocket engine development programs starts, these tools are relatively new to the design of rocket engines. In the NASA MC-1 engine program, the focus was to reduce the cost-to-weight ratio. The techniques for structural dynamics analysis practices, were tailored in this program to meet both production and structural design goals. Perturbation of rocket engine design parameters resulted in a number of MC-1 load cycles necessary to characterize the impact due to mass and stiffness changes. Evolution of loads and load extraction methodologies, parametric considerations and a discussion of load path sensitivities are important during the design and integration of a new engine system. During the final stages of development, it is important to verify the results of an engine system model to determine the validity of the results. During the final stages of the MC-1 program, hot-fire test results were obtained and compared to the structural design loads calculated by the engine system model. These comparisons are presented in this paper.

Clean catalytic combustor program

NASA Technical Reports Server (NTRS)

Ekstedt, E. E.; Lyon, T. F.; Sabla, P. E.; Dodds, W. J.

1983-01-01

A combustor program was conducted to evolve and to identify the technology needed for, and to establish the credibility of, using combustors with catalytic reactors in modern high-pressure-ratio aircraft turbine engines. Two selected catalytic combustor concepts were designed, fabricated, and evaluated. The combustors were sized for use in the NASA/General Electric Energy Efficient Engine (E3). One of the combustor designs was a basic parallel-staged double-annular combustor. The second design was also a parallel-staged combustor but employed reverse flow cannular catalytic reactors. Subcomponent tests of fuel injection systems and of catalytic reactors for use in the combustion system were also conducted. Very low-level pollutant emissions and excellent combustor performance were achieved. However, it was obvious from these tests that extensive development of fuel/air preparation systems and considerable advancement in the steady-state operating temperature capability of catalytic reactor materials will be required prior to the consideration of catalytic combustion systems for use in high-pressure-ratio aircraft turbine engines.

Affordability Engineering: Bridging the Gap Between Design and Cost

NASA Technical Reports Server (NTRS)

Reeves, J. D.; DePasquale, Dominic; Lim, Evan

2010-01-01

Affordability is a commonly used term that takes on numerous meanings depending on the context used. Within conceptual design of complex systems, the term generally implies comparisons between expected costs and expected resources. This characterization is largely correct, but does not convey the many nuances and considerations that are frequently misunderstood and underappreciated. In the most fundamental sense, affordability and cost directly relate to engineering and programmatic decisions made throughout development programs. Systems engineering texts point out that there is a temporal aspect to this relationship, for decisions made earlier in a program dictate design implications much more so than those made during latter phases. This paper explores affordability engineering and its many sub-disciplines by discussing how it can be considered an additional engineering discipline to be balanced throughout the systems engineering and systems analysis processes. Example methods of multidisciplinary design analysis with affordability as a key driver will be discussed, as will example methods of data visualization, probabilistic analysis, and other ways of relating design decisions to affordability results.

Environmental and sustainability ethics in supply chain management.

PubMed

Beamon, Benita M

2005-04-01

Environmentally Conscious Supply Chain Management (ECSCM refers to the control exerted over all immediate and eventual environmental effects of products and processes associated with converting raw materials into final products. While much work has been done in this area, the focus has traditionally been on either: product recovery (recycling, remanufacturing, or re-use) or the product design function only (e.g., design for environment). Environmental considerations in manufacturing are often viewed as separate from traditional, value-added considerations. However, the case can be made that professional engineers have an ethical responsibility to consider the immediate and eventual environmental impacts of products and processes that they design and/or manage. This paper describes ECSCM as a component of engineering ethics, and highlights the major issues associated with ethical decision-making in supply chain management.

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.

Performance of a Turboprop Engine with Heat Recovery in Off-Design Conditions

NASA Astrophysics Data System (ADS)

Andriani, Roberto; Ghezzi, Umberto; Gamma, Fausto; Ingenito, Antonella; Agresta, Antonio

2013-09-01

The research for fuel consumption and pollution reduction in new generation aero engines has indicated intercooling and regeneration as very effective methods for this purpose. Hence, different countries have joined their efforts in common research programs, to develop new gas turbine engines able to reduce considerably the fuel consumption and the ambient impact by means of these two techniques. To study their effects on the engine performance and characteristics, a thermodynamic numerical program that simulates the behavior of a turboprop engine with intercooling and regeneration in different operating conditions has been developed. After the parametric study, and the definition of the design conditions, the off-design analysis is carried on, comparing the main characteristics of the intercooled-regenerated turboprop with those of a conventional engine. Then, once a particular mission profile was fixed, the engine performance, in particular the equivalent power, the fuel consumption and the heat exchanger weight were discussed.

Energy Efficient Engine: Flight propulsion system final design and analysis

NASA Technical Reports Server (NTRS)

Davis, Donald Y.; Stearns, E. Marshall

1985-01-01

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

Implementing and Assessing the Converging-Diverging Model of Design in a Sequence of Sophomore Projects

ERIC Educational Resources Information Center

Dahm, Kevin; Riddell, William; Constans, Eric; Courtney, Jennifer; Harvey, Roberta; Von Lockette, Paris

2009-01-01

This paper discusses a sophomore-level course that teaches engineering design and technical writing. Historically, the course was taught using semester-long design projects. Most students' overall approach to design problems left considerable room for improvement. Many teams chose a design without investigating alternatives, and important…

Ethical considerations for a better collaboration between architects and structural engineers: design of buildings with reinforced concrete frame systems in earthquake zones.

PubMed

Hurol, Yonca

2014-06-01

Architects design building structures, although structural design is the profession of structural engineers. Thus, it is better for architects and structural engineers to collaborate starting from the initial phases of the architectural design. However, this is not very common because of the contradictory design processes and value systems held within the two professions. This article provides a platform upon which architects and structural engineers can resolve the value conflicts between them by analysing phases of the structural design of reinforced concrete frame systems in architecture, the criteria of the structural design for each phase and determining the conflicting values for each criterion. The results shown in the article demonstrate that the architectural design of structures is a complex process, which is based on contradictory values and value systems. Finally, the article suggests to architects and structural engineers to use Value Sensitive Design and to choose an appropriate team leader in order to resolve the unethical conflict between them and to avoid any unreasonable decision making.

A Question of Interface Design: How Do Online Service GUIs Measure Up?

ERIC Educational Resources Information Center

Head, Alison J.

1997-01-01

Describes recent improvements in graphical user interfaces (GUIs) offered by online services. Highlights include design considerations, including computer engineering capabilities and users' abilities; fundamental GUI design principles; user empowerment; visual communication and interaction; and an evaluation of online search interfaces. (LRW)

46 CFR 62.25-30 - Environmental design standards.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., and shutdown. (b) Low voltage electronics must be designed with due consideration for static discharge...-30 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING VITAL SYSTEM AUTOMATION General Requirements for All Automated Vital Systems § 62.25-30 Environmental design standards. (a...

46 CFR 62.25-30 - Environmental design standards.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., and shutdown. (b) Low voltage electronics must be designed with due consideration for static discharge...-30 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING VITAL SYSTEM AUTOMATION General Requirements for All Automated Vital Systems § 62.25-30 Environmental design standards. (a...

46 CFR 62.25-30 - Environmental design standards.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., and shutdown. (b) Low voltage electronics must be designed with due consideration for static discharge...-30 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING VITAL SYSTEM AUTOMATION General Requirements for All Automated Vital Systems § 62.25-30 Environmental design standards. (a...

46 CFR 62.25-30 - Environmental design standards.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., and shutdown. (b) Low voltage electronics must be designed with due consideration for static discharge...-30 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING VITAL SYSTEM AUTOMATION General Requirements for All Automated Vital Systems § 62.25-30 Environmental design standards. (a...

Silicon production process evaluations

NASA Technical Reports Server (NTRS)

1982-01-01

Chemical engineering analyses involving the preliminary process design of a plant (1,000 metric tons/year capacity) to produce silicon via the technology under consideration were accomplished. Major activities in the chemical engineering analyses included base case conditions, reaction chemistry, process flowsheet, material balance, energy balance, property data, equipment design, major equipment list, production labor and forward for economic analysis. The process design package provided detailed data for raw materials, utilities, major process equipment and production labor requirements necessary for polysilicon production in each process.

A computer aided engineering tool for ECLS systems

NASA Technical Reports Server (NTRS)

Bangham, Michal E.; Reuter, James L.

1987-01-01

The Computer-Aided Systems Engineering and Analysis tool used by NASA for environmental control and life support system design studies is capable of simulating atmospheric revitalization systems, water recovery and management systems, and single-phase active thermal control systems. The designer/analysis interface used is graphics-based, and allows the designer to build a model by constructing a schematic of the system under consideration. Data management functions are performed, and the program is translated into a format that is compatible with the solution routines.

EVA Roadmap: New Space Suit for the 21st Century

NASA Technical Reports Server (NTRS)

Yowell, Robert

1998-01-01

New spacesuit design considerations for the extra vehicular activity (EVA) of a manned Martian exploration mission are discussed. Considerations of the design includes:(1) regenerable CO2 removal, (2) a portable life support system (PLSS) which would include cryogenic oxygen produced from in-situ manufacture, (3) a power supply for the EVA, (4) the thermal control systems, (5) systems engineering, (5) space suit systems (materials, and mobility), (6) human considerations, such as improved biomedical sensors and astronaut comfort, (7) displays and controls, and robotic interfaces, such as rovers, and telerobotic commands.

Study of unconventional aircraft engines designed for low energy consumption

NASA Technical Reports Server (NTRS)

Neitzel, R. E.; Hirschkron, R.; Johnston, R. P.

1976-01-01

A study of unconventional engine cycle concepts, which may offer significantly lower energy consumption than conventional subsonic transport turbofans, is described herein. A number of unconventional engine concepts were identified and parametrically studied to determine their relative fuel-saving potential. Based on results from these studies, regenerative, geared, and variable-boost turbofans, and combinations thereof, were selected along with advanced turboprop cycles for further evaluation and refinement. Preliminary aerodynamic and mechanical designs of these unconventional engine configurations were conducted and mission performance was compared to a conventional, direct-drive turofan reference engine. Consideration is given to the unconventional concepts, and their state of readiness for application. Areas of needed technology advancement are identified.

Optimum Design of Hypersonic Airbreathing Propulsion

NASA Astrophysics Data System (ADS)

Kobayashi, Hiroaki; Sato, Tetsuya; Tanatsugu, Nobuhiro

The flight of Spaceplane is always under accelarating in the assent way and always under decelarating in the desent way and yet cruising in the return way. Besides, its flight envelope is considerably wider than that of airplane. Thus the integrated design method is required to build the best transportation system optimized taking into account the propulsion system and the airframe under the entire flight conditions. In this paper it is shown an optimization method on TSTO spaceplane system. Genetic algorithm (GA) was applied to optimize design parameters of engine, airframe, and trajectory simultaneously. Several types of engine were quantitatively compared using payload ratio as an evaluating function. It was concluded that precooled turbojets is the most promising engine for TSTO among Turbine Based Combined Cycle (TBCC) engines.

Critical Thinking on the Introduction of Digitization Within Engineering Training Systems in the Manufacturing Stage of Cast Parts

NASA Astrophysics Data System (ADS)

Lehene, T. R.; Samoilă, V.; Soporan, V. F.; Pădurețu, S.; Vescan, M. M.

2018-06-01

The paper aims to present a methodology for the analysis of the engineering training systems at the manufacturing stage of castings through critical engineering thinking. Its use [4, 5] requires the development of procedures capable of responding to the problems faced by engineering training in terms of acquiring the tools and procedures. The structure of the analysis took into consideration the following aspects: the motivation to use the proposed procedure, considerations on the engineering behavior, the design of the reasoning adapted to the analysis of the engineering training systems, the determination of the correlations in the processes of obtaining the cast products, the definition and calibration of the digital experiment, the definition and analysis of the factors influencing the last solidification area (the nature of the alloy, the shape of the mold and the casting geometry).

Energy efficient engine: Flight propulsion system, preliminary analysis and design update

NASA Technical Reports Server (NTRS)

Stearns, E. M.

1982-01-01

The preliminary design of General Electric's Energy Efficient Engine (E3) was reported in detail in 1980. Since then, the design has been refined and the components have been rig-tested. The changes which have occurred in the engine and a reassessment of the economic payoff are presented in this report. All goals for efficiency, environmental considerations, and economic payoff are being met. The E3 Flight Propulsion System has 14.9% lower sfc than a CF6-50C. It provides a 7.1% reduction in direct operating cost for a short haul domestic transport and 14.5% reduction for an international long distance transport.

Engineering Analysis Using a Web-based Protocol

NASA Technical Reports Server (NTRS)

Schoeffler, James D.; Claus, Russell W.

2002-01-01

This paper reviews the development of a web-based framework for engineering analysis. A one-dimensional, high-speed analysis code called LAPIN was used in this study, but the approach can be generalized to any engineering analysis tool. The web-based framework enables users to store, retrieve, and execute an engineering analysis from a standard web-browser. We review the encapsulation of the engineering data into the eXtensible Markup Language (XML) and various design considerations in the storage and retrieval of application data.

Genetic Engineering--A Lesson on Bioethics for the Classroom.

ERIC Educational Resources Information Center

Armstrong, Kerri; Weber, Kurt

1991-01-01

A unit designed to cover the topic of genetic engineering and its ethical considerations is presented. Students are expected to learn the material while using a debate format. A list of objectives for the unit, the debate format, and the results from an opinion questionnaire are described. (KR)

Human Factors and Robotics: Current Status and Future Prospects.

ERIC Educational Resources Information Center

Parsons, H. McIlvaine; Kearsley, Greg P.

The principal human factors engineering issue in robotics is the division of labor between automation (robots) and human beings. This issue reflects a prime human factors engineering consideration in systems design--what equipment should do and what operators and maintainers should do. Understanding of capabilities and limitations of robots and…

Optical engineering capstone design projects with industry sponsors

NASA Astrophysics Data System (ADS)

Bunch, Robert M.; Leisher, Paul O.; Granieri, Sergio C.

2014-09-01

Capstone senior design is the culmination of a student's undergraduate engineering education that prepares them for engineering practice. In fact, any engineering degree program that pursues accreditation by the Engineering Accreditation Commission of ABET must contain "a major design experience based on the knowledge and skills acquired in earlier course work and incorporating appropriate engineering standards and multiple realistic constraints." At Rose-Hulman, we offer an interdisciplinary Optical Engineering / Engineering Physics senior design curriculum that meets this requirement. Part of this curriculum is a two-course sequence where students work in teams on a design project leading to a functional prototype. The students begin work on their capstone project during the first week of their senior year. The courses are deliverable-driven and the students are held accountable for regular technical progress through weekly updates with their faculty advisor and mid-term design reviews. We have found that client-sponsored projects offer students an enriched engineering design experience as it ensures consideration of constraints and standards requirements similar to those that they will encounter as working engineers. Further, client-sponsored projects provide teams with an opportunity for regular customer interactions which help shape the product design. The process that we follow in both soliciting and helping to scope appropriate industry-related design projects will be described. In addition, an outline of the capstone course structure as well as methods used to hold teams accountable for technical milestones will be discussed. Illustrative examples of past projects will be provided.

Design and development of the Waukesha Custom Engine Control Air/Fuel Module

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

Moss, D.W.

1996-12-31

The Waukesha Custom Engine Control Air/Fuel Module (AFM) is designed to control the air-fuel ratio for all Waukesha carbureted, gaseous fueled, industrial engine. The AFM is programmed with a personal computer to run in one of four control modes: catalyst, best power, best economy, or lean-burn. One system can control naturally aspirated, turbocharged, in-line or vee engines. The basic system consists of an oxygen sensing system, intake manifold pressure transducer, electronic control module, actuator and exhaust thermocouple. The system permits correct operation of Waukesha engines in spite of changes in fuel pressure or temperature, engine load or speed, and fuelmore » composition. The system utilizes closed loop control and is centered about oxygen sensing technology. An innovative approach to applying oxygen sensors to industrial engines provides very good performance, greatly prolongs sensor life, and maintains sensor accuracy. Design considerations and operating results are given for application of the system to stationary, industrial engines operating on fuel gases of greatly varying composition.« less

Principles of Biomimetic Vascular Network Design Applied to a Tissue-Engineered Liver Scaffold

PubMed Central

Hoganson, David M.; Pryor, Howard I.; Spool, Ira D.; Burns, Owen H.; Gilmore, J. Randall

2010-01-01

Branched vascular networks are a central component of scaffold architecture for solid organ tissue engineering. In this work, seven biomimetic principles were established as the major guiding technical design considerations of a branched vascular network for a tissue-engineered scaffold. These biomimetic design principles were applied to a branched radial architecture to develop a liver-specific vascular network. Iterative design changes and computational fluid dynamic analysis were used to optimize the network before mold manufacturing. The vascular network mold was created using a new mold technique that achieves a 1:1 aspect ratio for all channels. In vitro blood flow testing confirmed the physiologic hemodynamics of the network as predicted by computational fluid dynamic analysis. These results indicate that this biomimetic liver vascular network design will provide a foundation for developing complex vascular networks for solid organ tissue engineering that achieve physiologic blood flow. PMID:20001254

Principles of biomimetic vascular network design applied to a tissue-engineered liver scaffold.

PubMed

Hoganson, David M; Pryor, Howard I; Spool, Ira D; Burns, Owen H; Gilmore, J Randall; Vacanti, Joseph P

2010-05-01

Branched vascular networks are a central component of scaffold architecture for solid organ tissue engineering. In this work, seven biomimetic principles were established as the major guiding technical design considerations of a branched vascular network for a tissue-engineered scaffold. These biomimetic design principles were applied to a branched radial architecture to develop a liver-specific vascular network. Iterative design changes and computational fluid dynamic analysis were used to optimize the network before mold manufacturing. The vascular network mold was created using a new mold technique that achieves a 1:1 aspect ratio for all channels. In vitro blood flow testing confirmed the physiologic hemodynamics of the network as predicted by computational fluid dynamic analysis. These results indicate that this biomimetic liver vascular network design will provide a foundation for developing complex vascular networks for solid organ tissue engineering that achieve physiologic blood flow.

Design Criteria for Microbiological Facilities at Fort Detrick. Volume II: Design Criteria

ERIC Educational Resources Information Center

Army Biological Labs., Fort Detrick, MD. Industrial Health and Safety Div.

Volume II of a two-volume manual of design criteria, based primarily on biological safety considerations. It is prepared for the use of architect-engineers in designing new or modified microbiological facilities for Fort Detrick, Maryland. Volume II is divided into the following sections: (1) architectural, (2) heating, ventilating, and air…

Some Current Issues in the Design of Flight Training Devices.

ERIC Educational Resources Information Center

Prophet, Wallace W.; And Others

The rationale is developed that training equipment should be selected or designed to furnish what the student needs to know and to be able to do to perform successfully on the operational job. Several considerations relevant to training equipment design from the systems engineering standpoint are examined. Suggested design features based upon…

Selection of a turbine cooling system applying multi-disciplinary design considerations.

PubMed

Glezer, B

2001-05-01

The presented paper describes a multi-disciplinary cooling selection approach applied to major gas turbine engine hot section components, including turbine nozzles, blades, discs, combustors and support structures, which maintain blade tip clearances. The paper demonstrates benefits of close interaction between participating disciplines starting from early phases of the hot section development. The approach targets advancements in engine performance and cost by optimizing the design process, often requiring compromises within individual disciplines.

Commercial considerations in tissue engineering

PubMed Central

Mansbridge, Jonathan

2006-01-01

Tissue engineering is a field with immense promise. Using the example of an early tissue-engineered skin implant, Dermagraft, factors involved in the successful commercial development of devices of this type are explored. Tissue engineering has to strike a balance between tissue culture, which is a resource-intensive activity, and business considerations that are concerned with minimizing cost and maximizing customer convenience. Bioreactor design takes place in a highly regulated environment, so factors to be incorporated into the concept include not only tissue culture considerations but also matters related to asepsis, scaleup, automation and ease of use by the final customer. Dermagraft is an allogeneic tissue. Stasis preservation, in this case cryopreservation, is essential in allogeneic tissue engineering, allowing sterility testing, inventory control and, in the case of Dermagraft, a cellular stress that may be important for hormesis following implantation. Although the use of allogeneic cells provides advantages in manufacturing under suitable conditions, it raises the spectre of immunological rejection. Such rejection has not been experienced with Dermagraft. Possible reasons for this and the vision of further application of allogeneic tissues are important considerations in future tissue-engineered cellular devices. This review illustrates approaches that indicate some of the criteria that may provide a basis for further developments. Marketing is a further requirement for success, which entails understanding of the mechanism of action of the procedure, and is illustrated for Dermagraft. The success of a tissue-engineered product is dependent on many interacting operations, some discussed here, each of which must be performed simultaneously and well. PMID:17005024

Commercial considerations in tissue engineering.

PubMed

Mansbridge, Jonathan

2006-10-01

Tissue engineering is a field with immense promise. Using the example of an early tissue-engineered skin implant, Dermagraft, factors involved in the successful commercial development of devices of this type are explored. Tissue engineering has to strike a balance between tissue culture, which is a resource-intensive activity, and business considerations that are concerned with minimizing cost and maximizing customer convenience. Bioreactor design takes place in a highly regulated environment, so factors to be incorporated into the concept include not only tissue culture considerations but also matters related to asepsis, scaleup, automation and ease of use by the final customer. Dermagraft is an allogeneic tissue. Stasis preservation, in this case cryopreservation, is essential in allogeneic tissue engineering, allowing sterility testing, inventory control and, in the case of Dermagraft, a cellular stress that may be important for hormesis following implantation. Although the use of allogeneic cells provides advantages in manufacturing under suitable conditions, it raises the spectre of immunological rejection. Such rejection has not been experienced with Dermagraft. Possible reasons for this and the vision of further application of allogeneic tissues are important considerations in future tissue-engineered cellular devices. This review illustrates approaches that indicate some of the criteria that may provide a basis for further developments. Marketing is a further requirement for success, which entails understanding of the mechanism of action of the procedure, and is illustrated for Dermagraft. The success of a tissue-engineered product is dependent on many interacting operations, some discussed here, each of which must be performed simultaneously and well.

Aircraft engine pollution reduction.

NASA Technical Reports Server (NTRS)

Rudey, R. A.

1972-01-01

The effect of engine operation on the types and levels of the major aircraft engine pollutants is described and the major factors governing the formation of these pollutants during the burning of hydrocarbon fuel are discussed. Methods which are being explored to reduce these pollutants are discussed and their application to several experimental research programs are pointed out. Results showing significant reductions in the levels of carbon monoxide, unburned hydrocarbons, and oxides of nitrogen obtained from experimental combustion research programs are presented and discussed to point out potential application to aircraft engines. An experimental program designed to develop and demonstrate these and other advanced, low pollution combustor design methods is described. Results that have been obtained to date indicate considerable promise for reducing advanced engine exhaust pollutants to levels significantly below current engines.

Cost/Effort Drivers and Decision Analysis

NASA Technical Reports Server (NTRS)

Seidel, Jonathan

2010-01-01

Engineering trade study analyses demand consideration of performance, cost and schedule impacts across the spectrum of alternative concepts and in direct reference to product requirements. Prior to detailed design, requirements are too often ill-defined (only goals ) and prone to creep, extending well beyond the Systems Requirements Review. Though lack of engineering design and definitive requirements inhibit the ability to perform detailed cost analyses, affordability trades still comprise the foundation of these future product decisions and must evolve in concert. This presentation excerpts results of the recent NASA subsonic Engine Concept Study for an Advanced Single Aisle Transport to demonstrate an affordability evaluation of performance characteristics and the subsequent impacts on engine architecture decisions. Applying the Process Based Economic Analysis Tool (PBEAT), development cost, production cost, as well as operation and support costs were considered in a traditional weighted ranking of the following system-level figures of merit: mission fuel burn, take-off noise, NOx emissions, and cruise speed. Weighting factors were varied to ascertain the architecture ranking sensitivities to these performance figures of merit with companion cost considerations. A more detailed examination of supersonic variable cycle engine cost is also briefly presented, with observations and recommendations for further refinements.

Thermal and Environmental Barrier Coating Development for Advanced Propulsion Engine Systems

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Miller, Robert A.; Fox, Dennis S.

2008-01-01

Ceramic thermal and environmental barrier coatings (TEBCs) are used in gas turbine engines to protect engine hot-section components in the harsh combustion environments, and extend component lifetimes. Advanced TEBCs that have significantly lower thermal conductivity, better thermal stability and higher toughness than current coatings will be beneficial for future low emission and high performance propulsion engine systems. In this paper, ceramic coating design and testing considerations will be described for turbine engine high temperature and high-heat-flux applications. Thermal barrier coatings for metallic turbine airfoils and thermal/environmental barrier coatings for SiC/SiC ceramic matrix composite (CMC) components for future supersonic aircraft propulsion engines will be emphasized. Further coating capability and durability improvements for the engine hot-section component applications can be expected by utilizing advanced modeling and design tools.

Factors to Consider in Designing Aerosol Inlet Systems for Engine Exhaust Plume Sampling

NASA Technical Reports Server (NTRS)

Anderson, Bruce

2004-01-01

This document consists of viewgraphs of charts and diagrams of considerations to take when sampling the engine exhaust plume. It includes a chart that compares the emissions from various fuels, a diagram and charts of the various processes and conditions that influence the particulate size and concentration,

Fundamentals of the Control of Gas-Turbine Power Plants for Aircraft. Part III Control of Jet Engines. Part 3; Control of Jet Engines

NASA Technical Reports Server (NTRS)

Kuehl, H.

1947-01-01

The basic principles of the control of TL ongincs are developed on .the basis of a quantitative investigation of the behavior of these behavior under various operating conditions with particular consideration of the simplifications pormissible in each case. Various possible means of control of jet engines are suggested and are illustrated by schematic designs.

Biomaterials for Tissue Engineering

PubMed Central

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

2013-01-01

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

Secondary Containment Design for the LLNL B801 Diala Oil Tank

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

Mertesdorf, E.

2016-12-14

Design is to add an extension to the secondary containment of tank T1-A3 at building 801. Piping from the inner tank penetrates the secondary containment tank below the liquid level of the primary tank. To meet Oil Pollution Prevention Regulation 40 CFR 120.7 the single wall piping needs to be provided with secondary containment. Steel Tank Institute (STI) conference publication states: §112.3(d)(1)(iii) –SPCC Plan requirements- Systems shall be designed in accordance with good engineering practice, including consideration of applicable industry standards and that procedures for required inspections and testing have been established. Section 112.7(a)(2) allows for deviations from specific rulemore » requirements, provided the Owner/operator responsible to select, document and implement alternate measure and a PE certifies the SPCC Plan in accordance with good engineering practices, including consideration of industry standards« less

Complex systems in metabolic engineering.

PubMed

Winkler, James D; Erickson, Keesha; Choudhury, Alaksh; Halweg-Edwards, Andrea L; Gill, Ryan T

2015-12-01

Metabolic engineers manipulate intricate biological networks to build efficient biological machines. The inherent complexity of this task, derived from the extensive and often unknown interconnectivity between and within these networks, often prevents researchers from achieving desired performance. Other fields have developed methods to tackle the issue of complexity for their unique subset of engineering problems, but to date, there has not been extensive and comprehensive examination of how metabolic engineers use existing tools to ameliorate this effect on their own research projects. In this review, we examine how complexity affects engineering at the protein, pathway, and genome levels within an organism, and the tools for handling these issues to achieve high-performing strain designs. Quantitative complexity metrics and their applications to metabolic engineering versus traditional engineering fields are also discussed. We conclude by predicting how metabolic engineering practices may advance in light of an explicit consideration of design complexity. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Role of Formal Experiment Design in Hypersonic Flight System Technology Development

NASA Technical Reports Server (NTRS)

McClinton, Charles R.; Ferlemann, Shelly M.; Rock, Ken E.; Ferlemann, Paul G.

2002-01-01

Hypersonic airbreathing engine (scramjet) powered vehicles are being considered to replace conventional rocket-powered launch systems. Effective utilization of scramjet engines requires careful integration with the air vehicle. This integration synergistically combines aerodynamic forces with propulsive cycle functions of the engine. Due to the highly integrated nature of the hypersonic vehicle design problem, the large flight envelope, and the large number of design variables, the use of a statistical design approach in design is effective. Modern Design-of-Experiments (MDOE) has been used throughout the Hyper-X program, for both systems analysis and experimental testing. Application of MDOE fall into four categories: (1) experimental testing; (2) studies of unit phenomena; (3) refining engine design; and (4) full vehicle system optimization. The MDOE process also provides analytical models, which are also used to document lessons learned, supplement low-level design tools, and accelerate future studies. This paper will discuss the design considerations for scramjet-powered vehicles, specifics of MDOE utilized for Hyper-X, and present highlights from the use of these MDOE methods within the Hyper-X Program.

Citrate-Based Biomaterials and Their Applications in Regenerative Engineering

PubMed Central

Tran, Richard T.; Yang, Jian; Ameer, Guillermo A.

2015-01-01

Advances in biomaterials science and engineering are crucial to translating regenerative engineering, an emerging field that aims to recreate complex tissues, into clinical practice. In this regard, citrate-based biomaterials have become an important tool owing to their versatile material and biological characteristics including unique antioxidant, antimicrobial, adhesive, and fluorescent properties. This review discusses fundamental design considerations, strategies to incorporate unique functionality, and examples of how citrate-based biomaterials can be an enabling technology for regenerative engineering. PMID:27004046

Flight Test Engineering

NASA Technical Reports Server (NTRS)

Pavlock, Kate Maureen

2013-01-01

Although the scope of flight test engineering efforts may vary among organizations, all point to a common theme: flight test engineering is an interdisciplinary effort to test an asset in its operational flight environment. Upfront planning where design, implementation, and test efforts are clearly aligned with the flight test objective are keys to success. This chapter provides a top level perspective of flight test engineering for the non-expert. Additional research and reading on the topic is encouraged to develop a deeper understanding of specific considerations involved in each phase of flight test engineering.

Urban Principle of Water Sensitive Design in Kampung Kamboja at Pontianak City

NASA Astrophysics Data System (ADS)

Hasriyanti, N.; Ryanti, E.

2017-07-01

This study will define the design principles of settlement area banks of the Kapuas Pontianak to approach the concept of water sensitive urban design (WSUD) in densely populated residential areas. Using a case study of a region densely located on the banks of the river with engineering literature to formulate the aspects taken into consideration and the components are arranged in the design, analysis descriptive paradigm rationalistic to identify the characteristics of residential areas riverbank with consideration of elements WSUD and formulate design principles residential area that is sensitive to water. This research is important to do because of problems related to the water management system in the settlement bank of the river in the city of Pontianak do not maximize. So that the primacy of this study contains several objectives to be achieved is to identify the characteristics of the settlement area riverbanks under consideration aspects areas design that is sensitive to water and principle areas design that will formulate the structure of the existing problems related to the needs of the community infrastructure facilities infrastructure neighborhoods and formulate and create guidelines for appropriate technology for integrated water management systems in the residential area of the riverbank and engineering design for the settlements are sensitive to water (WSUD). The final aim of the study is expected to achieve water management systems in residential areas by utilizing the abundant rainwater availability by using LID (Low Impact Development) through the concept of urban design that sensitive water

Multidisciplinary Analysis of a Hypersonic Engine

NASA Technical Reports Server (NTRS)

Suresh, Ambady; Stewart, Mark

2003-01-01

The objective is to develop high fidelity tools that can influence ISTAR design In particular, tools for coupling Fluid-Thermal-Structural simulations RBCC/TBCC designers carefully balance aerodynamic, thermal, weight, & structural considerations; consistent multidisciplinary solutions reveal details (at modest cost) At Scram mode design point, simulations give details of inlet & combustor performance, thermal loads, structural deflections.

Introducing Students to Bio-Inspiration and Biomimetic Design: A Workshop Experience

ERIC Educational Resources Information Center

Santulli, Carlo; Langella, Carla

2011-01-01

In recent years, bio-inspired approach to design has gained considerable interest between designers, engineers and end-users. However, there are difficulties in introducing bio-inspiration concepts in the university curriculum in that they involve multi-disciplinary work, which can only possibly be successfully delivered by a team with integrated…

Preliminary design of a supersonic Short Takeoff and Vertical Landing (STOVL) fighter aircraft

NASA Technical Reports Server (NTRS)

Cox, Brian; Borchers, Paul; Gomer, Charlie; Henderson, Dean; Jacobs, Tavis; Lawson, Todd; Peterson, Eric; Ross, Tweed, III; Bellmard, Larry

1990-01-01

The preliminary design study of a supersonic Short Takeoff and Vertical Landing (STOVL) fighter is presented. A brief historical survey of powered lift vehicles was presented, followed by a technology assessment of the latest supersonic STOVL engine cycles under consideration by industry and government in the U.S. and UK. A survey of operational fighter/attack aircraft and the modern battlefield scenario were completed to develop, respectively, the performance requirements and mission profiles for the study. Three configurations were initially investigated with the following engine cycles: a hybrid fan vectored thrust cycle, a lift+lift/cruise cycle, and a mixed flow vectored thrust cycle. The lift+lift/cruise aircraft configuration was selected for detailed design work which consisted of: (1) a material selection and structural layout, including engine removal considerations, (2) an aircraft systems layout, (3) a weapons integration model showing the internal weapons bay mechanism, (4) inlet and nozzle integration, (5) an aircraft suckdown prediction, (6) an aircraft stability and control analysis, including a takeoff, hover, and transition control analysis, (7) a performance and mission capability study, and (8) a life cycle cost analysis. A supersonic fighter aircraft with STOVL capability with the lift+lift/cruise engine cycle seems a viable option for the next generation fighter.

A static analysis method for barge impact design of bridges with consideration of dynamic amplification : summary.

DOT National Transportation Integrated Search

2009-11-01

Several hundred Florida bridges span waterways deep enough for barge traffic. To ensure a bridge is capable of withstanding the potential impact of a barge collision, engineers use design specifications recommended by the American Association of Stat...

10 CFR Appendix B to Part 436 - Goal Setting Methodology

Code of Federal Regulations, 2010 CFR

2010-01-01

... limitations; environmental conditions (tropical versus arctic, etc.); budget levels for fuel, operations..., maintenance, engineering, design, and economics, and consideration of the measures identified in Appendix C...

Intelligent Life-Extending Controls for Aircraft Engines Studied

NASA Technical Reports Server (NTRS)

Guo, Ten-Huei

2005-01-01

Current aircraft engine controllers are designed and operated to provide desired performance and stability margins. Except for the hard limits for extreme conditions, engine controllers do not usually take engine component life into consideration during the controller design and operation. The end result is that aircraft pilots regularly operate engines under unnecessarily harsh conditions to strive for optimum performance. The NASA Glenn Research Center and its industrial and academic partners have been working together toward an intelligent control concept that will include engine life as part of the controller design criteria. This research includes the study of the relationship between control action and engine component life as well as the design of an intelligent control algorithm to provide proper tradeoffs between performance and engine life. This approach is expected to maintain operating safety while minimizing overall operating costs. In this study, the thermomechanical fatigue (TMF) of a critical component was selected to demonstrate how an intelligent engine control algorithm can significantly extend engine life with only a very small sacrifice in performance. An intelligent engine control scheme based on modifying the high-pressure spool speed (NH) was proposed to reduce TMF damage from ground idle to takeoff. The NH acceleration schedule was optimized to minimize the TMF damage for a given rise-time constraint, which represents the performance requirement. The intelligent engine control scheme was used to simulate a commercial short-haul aircraft engine.

Challenges Surrounding the Injection and Arrival of Targets at LIFE Fusion Chamber Center

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

Miles, R; Spaeth, M; Manes, K

2010-12-01

IFE target designers must consider several engineering requirements in addition to the physics requirements for successful target implosion. These considerations include low target cost, high manufacturing throughput, the ability of the target to survive the injection into the fusion chamber and arrive in a condition and physical position consistent with proper laser-target interaction and ease of post-implosion debris removal. This article briefly describes these considerations for the Laser Inertial Fusion-based Energy (LIFE) targets currently being designed.

Emotional engineers: toward morally responsible design.

PubMed

Roeser, Sabine

2012-03-01

Engineers are normally seen as the archetype of people who make decisions in a rational and quantitative way. However, technological design is not value neutral. The way a technology is designed determines its possibilities, which can, for better or for worse, have consequences for human wellbeing. This leads various scholars to the claim that engineers should explicitly take into account ethical considerations. They are at the cradle of new technological developments and can thereby influence the possible risks and benefits more directly than anybody else. I have argued elsewhere that emotions are an indispensable source of ethical insight into ethical aspects of risk. In this paper I will argue that this means that engineers should also include emotional reflection into their work. This requires a new understanding of the competencies of engineers: they should not be unemotional calculators; quite the opposite, they should work to cultivate their moral emotions and sensitivity, in order to be engaged in morally responsible engineering. © The Author(s) 2010. This article is published with open access at Springerlink.com

Photovoltaic power system reliability considerations

NASA Technical Reports Server (NTRS)

Lalli, V. R.

1980-01-01

An example of how modern engineering and safety techniques can be used to assure the reliable and safe operation of photovoltaic power systems is presented. This particular application is for a solar cell power system demonstration project designed to provide electric power requirements for remote villages. The techniques utilized involve a definition of the power system natural and operating environment, use of design criteria and analysis techniques, an awareness of potential problems via the inherent reliability and FMEA methods, and use of fail-safe and planned spare parts engineering philosophy.

Introducing Decision Making under Uncertainty and Strategic Considerations in Engineering Design

ERIC Educational Resources Information Center

Kosmopoulou, Georgia; Jog, Chintamani; Freeman, Margaret; Papavassiliou, Dimitrios V.

2010-01-01

Chemical Engineering graduates will face challenges at the workplace that even their peers who graduated a few years ago were not expected to face. One such major challenge is the management and operation of companies and plants under conditions of uncertainty and the need to make decisions in competitive situations. Modern developments in…

Performance mapping of a 30 cm engineering model thruster

NASA Technical Reports Server (NTRS)

Poeschel, R. L.; Vahrenkamp, R. P.

1975-01-01

A 30 cm thruster representative of the engineering model design has been tested over a wide range of operating parameters to document performance characteristics such as electrical and propellant efficiencies, double ion and beam divergence thrust loss, component equilibrium temperatures, operational stability, etc. Data obtained show that optimum power throttling, in terms of maximum thruster efficiency, is not highly sensitive to parameter selection. Consequently, considerations of stability, discharge chamber erosion, thrust losses, etc. can be made the determining factors for parameter selection in power throttling operations. Options in parameter selection based on these considerations are discussed.

Considerations for a design and operations knowledge support system for Space Station Freedom

NASA Technical Reports Server (NTRS)

Erickson, Jon D.; Crouse, Kenneth H.; Wechsler, Donald B.; Flaherty, Douglas R.

1989-01-01

Engineering and operations of modern engineered systems depend critically upon detailed design and operations knowledge that is accurate and authoritative. A design and operations knowledge support system (DOKSS) is a modern computer-based information system providing knowledge about the creation, evolution, and growth of an engineered system. The purpose of a DOKSS is to provide convenient and effective access to this multifaceted information. The complexity of Space Station Freedom's (SSF's) systems, elements, interfaces, and organizations makes convenient access to design knowledge especially important, when compared to simpler systems. The life cycle length, being 30 or more years, adds a new dimension to space operations, maintenance, and evolution. Provided here is a review and discussion of design knowledge support systems to be delivered and operated as a critical part of the engineered system. A concept of a DOKSS for Space Station Freedom (SSF) is presented. This is followed by a detailed discussion of a DOKSS for the Lyndon B. Johnson Space Center and Work Package-2 portions of SSF.

Structure and Management of an Engineering Senior Design Course.

PubMed

Tanaka, Martin L; Fischer, Kenneth J

2016-07-01

The design of products and processes is an important area in engineering. Students in engineering schools learn fundamental principles in their courses but often lack an opportunity to apply these methods to real-world problems until their senior year. This article describes important elements that should be incorporated into a senior capstone design course. It includes a description of the general principles used in engineering design and a discussion of why students often have difficulty with application and revert to trial and error methods. The structure of a properly designed capstone course is dissected and its individual components are evaluated. Major components include assessing resources, identifying projects, establishing teams, understanding requirements, developing conceptual designs, creating detailed designs, building prototypes, testing performance, and final presentations. In addition to the course design, team management and effective mentoring are critical to success. This article includes suggested guidelines and tips for effective design team leadership, attention to detail, investment of time, and managing project scope. Furthermore, the importance of understanding business culture, displaying professionalism, and considerations of different types of senior projects is discussed. Through a well-designed course and proper mentoring, students will learn to apply their engineering skills and gain basic business knowledge that will prepare them for entry-level positions in industry.

Theory and Design of Flight-Vehicle Engines

NASA Technical Reports Server (NTRS)

Zhdanov, V. T. (Editor); Kurziner, R. I. (Editor)

1987-01-01

Papers are presented on such topics as the testing of aircraft engines, errors in the experimental determination of the parameters of scramjet engines, the effect of the nonuniformity of supersonic flow with shocks on friction and heat transfer in the channel of a hypersonic ramjet engine, and the selection of the basic parameters of cooled GTE turbines. Consideration is also given to the choice of optimal total wedge angle for the acceleration of aerospace vehicles, the theory of an electromagnetic-resonator engine, the dynamic characteristics of the pumps and turbines of liquid propellant rocket engines in transition regimes, and a hierarchy of mathematical models for spacecraft control engines.

Engineering Trade-off Considerations Regarding Design-for-Security, Design-for-Verification, and Design-for-Test

NASA Technical Reports Server (NTRS)

Berg, Melanie; Label, Kenneth

2018-01-01

The United States government has identified that application specific integrated circuit (ASIC) and field programmable gate array (FPGA) hardware are at risk from a variety of adversary attacks. This finding affects system security and trust. Consequently, processes are being developed for system mitigation and countermeasure application. The scope of this tutorial pertains to potential vulnerabilities and countermeasures within the ASIC/FPGA design cycle. The presentation demonstrates how design practices can affect the risk for the adversary to: change circuitry, steal intellectual property, and listen to data operations. An important portion of the design cycle is assuring the design is working as specified or as expected. This is accomplished by exhaustive testing of the target design. Alternatively, it has been shown that well established schemes for test coverage enhancement (design-for-verification (DFV) and design-for-test (DFT)) can create conduits for adversary accessibility. As a result, it is essential to perform a trade between robust test coverage versus reliable design implementation. The goal of this tutorial is to explain the evolution of design practices; review adversary accessibility points due to DFV and DFT circuitry insertion (back door circuitry); and to describe common engineering trade-off considerations for test versus adversary threats.

Economical space power systems

NASA Technical Reports Server (NTRS)

Burkholder, J. H.

1980-01-01

A commercial approach to design and fabrication of an economical space power system is investigated. Cost projections are based on a 2 kW space power system conceptual design taking into consideration the capability for serviceability, constraints of operation in space, and commercial production engineering approaches. A breakdown of the system design, documentation, fabrication, and reliability and quality assurance estimated costs are detailed.

Shape Memory Alloy Actuator Design: CASMART Collaborative Best Practices

NASA Technical Reports Server (NTRS)

Benafan, Othmane; Brown, Jeff; Calkins, F. Tad; Kumar, Parikshith; Stebner, Aaron; Turner, Travis; Vaidyanathan, Raj; Webster, John; Young, Marcus L.

2011-01-01

Upon examination of shape memory alloy (SMA) actuation designs, there are many considerations and methodologies that are common to them all. A goal of CASMART's design working group is to compile the collective experiences of CASMART's member organizations into a single medium that engineers can then use to make the best decisions regarding SMA system design. In this paper, a review of recent work toward this goal is presented, spanning a wide range of design aspects including evaluation, properties, testing, modeling, alloy selection, fabrication, actuator processing, design optimization, controls, and system integration. We have documented each aspect, based on our collective experiences, so that the design engineer may access the tools and information needed to successfully design and develop SMA systems. Through comparison of several case studies, it is shown that there is not an obvious single, linear route a designer can adopt to navigate the path of concept to product. SMA engineering aspects will have different priorities and emphasis for different applications.

Procedure for developing experimental designs for accelerated tests for service-life prediction. [for solar cell modules

NASA Technical Reports Server (NTRS)

Thomas, R. E.; Gaines, G. B.

1978-01-01

Recommended design procedures to reduce the complete factorial design by retaining information on anticipated important interaction effects, and by generally giving up information on unconditional main effects are discussed. A hypothetical photovoltaic module used in the test design is presented. Judgments were made of the relative importance of various environmental stresses such as UV radiation, abrasion, chemical attack, temperature, mechanical stress, relative humidity and voltage. Consideration is given to a complete factorial design and its graphical representation, elimination of selected test conditions, examination and improvement of an engineering design, and parametric study. The resulting design consists of a mix of conditional main effects and conditional interactions and represents a compromise between engineering and statistical requirements.

Energy efficient engine high-pressure turbine detailed design report

NASA Technical Reports Server (NTRS)

Thulin, R. D.; Howe, D. C.; Singer, I. D.

1982-01-01

The energy efficient engine high-pressure turbine is a single stage system based on technology advancements in the areas of aerodynamics, structures and materials to achieve high performance, low operating economics and durability commensurate with commercial service requirements. Low loss performance features combined with a low through-flow velocity approach results in a predicted efficiency of 88.8 for a flight propulsion system. Turbine airfoil durability goals are achieved through the use of advanced high-strength and high-temperature capability single crystal materials and effective cooling management. Overall, this design reflects a considerable extension in turbine technology that is applicable to future, energy efficient gas-turbine engines.

Intelligent Life-Extending Controls for Aircraft Engines

NASA Technical Reports Server (NTRS)

Guo, Ten-Huei; Chen, Philip; Jaw, Link

2005-01-01

Aircraft engine controllers are designed and operated to provide desired performance and stability margins. The purpose of life-extending-control (LEC) is to study the relationship between control action and engine component life usage, and to design an intelligent control algorithm to provide proper trade-offs between performance and engine life usage. The benefit of this approach is that it is expected to maintain safety while minimizing the overall operating costs. With the advances of computer technology, engine operation models, and damage physics, it is necessary to reevaluate the control strategy fro overall operating cost consideration. This paper uses the thermo-mechanical fatigue (TMF) of a critical component to demonstrate how an intelligent engine control algorithm can drastically reduce the engine life usage with minimum sacrifice in performance. A Monte Carlo simulation is also performed to evaluate the likely engine damage accumulation under various operating conditions. The simulation results show that an optimized acceleration schedule can provide a significant life saving in selected engine components.

GN&C Engineering Best Practices for Human-Rated Spacecraft Systems

NASA Technical Reports Server (NTRS)

Dennehy, Cornelius J.; Lebsock, Kenneth; West, John

2007-01-01

The NASA Engineering and Safety Center (NESC) recently completed an in-depth assessment to identify a comprehensive set of engineering considerations for the Design, Development, Test and Evaluation (DDT&E) of safe and reliable human-rated spacecraft systems. Reliability subject matter experts, discipline experts, and systems engineering experts were brought together to synthesize the current "best practices" both at the spacecraft system and subsystems levels. The objective of this paper is to summarize, for the larger Community of Practice, the initial set of Guidance, Navigation and Control (GN&C) engineering Best Practices as identified by this NESC assessment process.

GN&C Engineering Best Practices for Human-Rated Spacecraft System

NASA Technical Reports Server (NTRS)

Dennehy, Cornelius J.; Lebsock, Kenneth; West, John

2008-01-01

The NASA Engineering and Safety Center (NESC) recently completed an in-depth assessment to identify a comprehensive set of engineering considerations for the Design, Development, Test and Evaluation (DDT&E) of safe and reliable human-rated spacecraft systems. Reliability subject matter experts, discipline experts, and systems engineering experts were brought together to synthesize the current "best practices" both at the spacecraft system and subsystems levels. The objective of this paper is to summarize, for the larger Community of Practice, the initial set of Guidance, Navigation and Control (GN&C) engineering Best Practices as identified by this NESC assessment process.

GN&C Engineering Best Practices For Human-Rated Spacecraft Systems

NASA Technical Reports Server (NTRS)

Dennehy, Cornelius J.; Lebsock, Kenneth; West, John

2007-01-01

The NASA Engineering and Safety Center (NESC) recently completed an in-depth assessment to identify a comprehensive set of engineering considerations for the Design, Development, Test and Evaluation (DDT&E) of safe and reliable human-rated spacecraft systems. Reliability subject matter experts, discipline experts, and systems engineering experts were brought together to synthesize the current "best practices" both at the spacecraft system and subsystems levels. The objective of this paper is to summarize, for the larger Community of Practice, the initial set of Guidance, Navigation and Control (GN&C) engineering Best Practices as identified by this NESC assessment process.

High-Speed, High-Temperature Finger Seal Test Evaluated

NASA Technical Reports Server (NTRS)

Proctor, Margaret P.

2003-01-01

A finger seal, designed and fabricated by Honeywell Engines, Systems and Services, was tested at the NASA Glenn Research Center at surface speeds up to 1200 ft/s, air temperatures up to 1200 F, and pressures across the seal of 75 psid. These are the first test results obtained with NASA s new High-Temperature, High-Speed Turbine Seal Test Rig (see the photograph). The finger seal is an innovative design recently patented by AlliedSignal Engines, which has demonstrated considerably lower leakage than commonly used labyrinth seals and is considerably cheaper than brush seals. The cost to produce finger seals is estimated to be about half of the cost to produce brush seals. Replacing labyrinth seals with fingers seals at locations that have high-pressure drops in gas turbine engines, typically main engine and thrust seals, can reduce air leakage at each location by 50 percent or more. This directly results in a 0.7- to 1.4-percent reduction in specific fuel consumption and a 0.35- to 0.7-percent reduction in direct operating costs . Because the finger seal is a contacting seal, this testing was conducted to address concerns about its heat generation and life capability at the higher speeds and temperatures required for advanced engines. The test results showed that the seal leakage and wear performance are acceptable for advanced engines.

System safety in Stirling engine development

NASA Technical Reports Server (NTRS)

Bankaitis, H.

1981-01-01

The DOE/NASA Stirling Engine Project Office has required that contractors make safety considerations an integral part of all phases of the Stirling engine development program. As an integral part of each engine design subtask, analyses are evolved to determine possible modes of failure. The accepted system safety analysis techniques (Fault Tree, FMEA, Hazards Analysis, etc.) are applied in various degrees of extent at the system, subsystem and component levels. The primary objectives are to identify critical failure areas, to enable removal of susceptibility to such failures or their effects from the system and to minimize risk.

High-Payoff Space Transportation Design Approach with a Technology Integration Strategy

NASA Technical Reports Server (NTRS)

McCleskey, C. M.; Rhodes, R. E.; Chen, T.; Robinson, J.

2011-01-01

A general architectural design sequence is described to create a highly efficient, operable, and supportable design that achieves an affordable, repeatable, and sustainable transportation function. The paper covers the following aspects of this approach in more detail: (1) vehicle architectural concept considerations (including important strategies for greater reusability); (2) vehicle element propulsion system packaging considerations; (3) vehicle element functional definition; (4) external ground servicing and access considerations; and, (5) simplified guidance, navigation, flight control and avionics communications considerations. Additionally, a technology integration strategy is forwarded that includes: (a) ground and flight test prior to production commitments; (b) parallel stage propellant storage, such as concentric-nested tanks; (c) high thrust, LOX-rich, LOX-cooled first stage earth-to-orbit main engine; (d) non-toxic, day-of-launch-loaded propellants for upper stages and in-space propulsion; (e) electric propulsion and aero stage control.

Engineering Design Handbook: Maintenance Engineering Techniques

DTIC Science & Technology

1975-06-30

resistance and lustrous appearance. Relatively expensive. Spec- ify hard chrome plate for exceptionally hard abrasion-resistant surface . Has low...36 Bearing Seals 3-36 Derating 3-37 Lubrication 3-37 Fixed Joints 3-37 Self-adjusting Components ." 3-38 Corrosion Aspects 3-38 Material...Troubleshooting Considerations by Army Command Category •■■ Fixed Plant/Defense Communications and USASA Equipment Army Aircraft Automotive and

An Assessment of Technology for Turbojet Engine Rotor Failures

NASA Technical Reports Server (NTRS)

Witmer, E. A. (Editor)

1977-01-01

Design considerations, objectives, and approaches used in containing rotor burst debris are discussed. Methods are given for determining the fracture resistance of various materials used in providing lightweight shielding from fragment impact.

Ethical Considerations in Tissue Engineering Research: Case Studies in Translation

PubMed Central

Baker, Hannah B.; McQuilling, John P.

2016-01-01

Tissue engineering research is a complex process that requires investigators to focus on the relationship between their research and anticipated gains in both knowledge and treatment improvements. The ethical considerations arising from tissue engineering research are similarly complex when addressing the translational progression from bench to bedside, and investigators in the field of tissue engineering act as moral agents at each step of their research along the translational pathway, from early benchwork and preclinical studies to clinical research. This review highlights the ethical considerations and challenges at each stage of research, by comparing issues surrounding two translational tissue engineering technologies: the bioartificial pancreas and a tissue engineered skeletal muscle construct. We present relevant ethical issues and questions to consider at each step along the translational pathway, from the basic science bench to preclinical research to first-in-human clinical trials. Topics at the bench level include maintaining data integrity, appropriate reporting and dissemination of results, and ensuring that studies are designed to yield results suitable for advancing research. Topics in preclinical research include the principle of “modest translational distance” and appropriate animal models. Topics in clinical research include key issues that arise in early-stage clinical trials, including selection of patient-subjects, disclosure of uncertainty, and defining success. The comparison of these two technologies and their ethical issues brings to light many challenges for translational tissue engineering research and provides guidance for investigators engaged in development of any tissue engineering technology. PMID:26282436

Ethical considerations in tissue engineering research: Case studies in translation.

PubMed

Baker, Hannah B; McQuilling, John P; King, Nancy M P

2016-04-15

Tissue engineering research is a complex process that requires investigators to focus on the relationship between their research and anticipated gains in both knowledge and treatment improvements. The ethical considerations arising from tissue engineering research are similarly complex when addressing the translational progression from bench to bedside, and investigators in the field of tissue engineering act as moral agents at each step of their research along the translational pathway, from early benchwork and preclinical studies to clinical research. This review highlights the ethical considerations and challenges at each stage of research, by comparing issues surrounding two translational tissue engineering technologies: the bioartificial pancreas and a tissue engineered skeletal muscle construct. We present relevant ethical issues and questions to consider at each step along the translational pathway, from the basic science bench to preclinical research to first-in-human clinical trials. Topics at the bench level include maintaining data integrity, appropriate reporting and dissemination of results, and ensuring that studies are designed to yield results suitable for advancing research. Topics in preclinical research include the principle of "modest translational distance" and appropriate animal models. Topics in clinical research include key issues that arise in early-stage clinical trials, including selection of patient-subjects, disclosure of uncertainty, and defining success. The comparison of these two technologies and their ethical issues brings to light many challenges for translational tissue engineering research and provides guidance for investigators engaged in development of any tissue engineering technology. Copyright © 2015 Elsevier Inc. All rights reserved.

Performance retention of the RB211 powerplant in service

NASA Technical Reports Server (NTRS)

Astridge, B. L.; Pinder, J. T.

1981-01-01

An understanding of the mechanisms of deterioration is essential in order that features to counteract performance degradation can be built into the basic design of an engine and nacelle. Furthermore, the interpretation must be continued in service for effective feedback to provide modifications which may be necessary in maintaining a satisfactory performance retention program. The in service assessment must be accurate as to magnitude and causes and this requires consideration of: (1) the powerplant as a complete entity, i.e., the engine components and nacelle including the thrust reverser; (2) measurement of performance in flight rather than by sole reliance on the scaling of test cell data to flight conditions (although some correlation should be possible); and (3) the relationship of engine parts condition to overhaul performance and in flight deterioration level of that engine. These aspects are addressed by consideration of the RB211 engine in service in both the Lockheed L1011 Tristar and Boeing 747 aircraft.

A 2.5 kW advanced technology ion thruster

NASA Technical Reports Server (NTRS)

Poeschel, R. L.

1974-01-01

A program has been conducted in order to improve the performance characteristics of 30 cm thrusters. This program was divided into three distinct, but related tasks: (1) the discharge chamber and component design modifications proposed for inclusion in the engineering model thruster were evaluated and engineering specifications were verified; (2) thrust losses which result from the contributions of double charged ions and nonaxial ion trajectories to the ion beam current were measured and (3) the specification and verification of power processor and control requirements of the engineering model thruster design were demonstrated. Proven design modifications which provide improved efficiencies are incorporated into the engineering model thruster during a structural re-design without introducing additional delay in schedule or new risks. In addition, a considerable amount of data is generated on the relation of double ion production and beam divergence to thruster parameters. Overall thruster efficiency is increased from 68% to 71% at full power, including corrections for double ion and beam divergence thrust losses.

Eco-innovative design approach: Integrating quality and environmental aspects in prioritizing and solving engineering problems

NASA Astrophysics Data System (ADS)

Chakroun, Mahmoud; Gogu, Grigore; Pacaud, Thomas; Thirion, François

2014-09-01

This study proposes an eco-innovative design process taking into consideration quality and environmental aspects in prioritizing and solving technical engineering problems. This approach provides a synergy between the Life Cycle Assessment (LCA), the nonquality matrix, the Theory of Inventive Problem Solving (TRIZ), morphological analysis and the Analytical Hierarchy Process (AHP). In the sequence of these tools, LCA assesses the environmental impacts generated by the system. Then, for a better consideration of environmental aspects, a new tool is developed, the non-quality matrix, which defines the problem to be solved first from an environmental point of view. The TRIZ method allows the generation of new concepts and contradiction resolution. Then, the morphological analysis offers the possibility of extending the search space of solutions in a design problem in a systematic way. Finally, the AHP identifies the promising solution(s) by providing a clear logic for the choice made. Their usefulness has been demonstrated through their application to a case study involving a centrifugal spreader with spinning discs.

Progress in performance enhancement methods for capacitive silicon resonators

NASA Astrophysics Data System (ADS)

Van Toan, Nguyen; Ono, Takahito

2017-11-01

In this paper, we review the progress in recent studies on the performance enhancement methods for capacitive silicon resonators. We provide information on various fabrication technologies and design considerations that can be employed to improve the performance of capacitive silicon resonators, including low motional resistance, small insertion loss, and high quality factor (Q). This paper contains an overview of device structures and working principles, fabrication technologies consisting of hermetic packaging, deep reactive-ion etching and neutral beam etching, and design considerations including mechanically coupled, movable electrode structures and piezoresistive heat engines.

The trajectories of Prevention through Design in construction.

PubMed

Toole, T Michael; Gambatese, John

2008-01-01

Construction Hazards Prevention through Design (CHPtD) is a process in which engineers and architects explicitly consider the safety of construction workers during the design process. Although articles on CHPtD have appeared in top construction journals, the literature has not addressed technical principles underlying CHPtD to help designers better perform CHPtD, to facilitate the development of additional CHPtD tools, and to predict the future path of CHPtD. This theoretical paper uses the existing literature on CHPtD and current action research associated with several CHPtD workgroups to analyze how CHPtD will likely evolve over the coming decades. There are four trajectories along which CHPtD will progress. (a) Designs will increasingly facilitate prefabricated construction; (b) designers will increasingly choose materials and systems that are inherently safer than alternatives; (c) designers will increasingly perform construction engineering; and (d) designers will increasingly apply spatial considerations to reduce worker hazards. By understanding how CHPtD may be manifested in the engineering-procurement-construction (EPC) industry, practitioners can better prepare for adopting CHPtD within their organizations and construction and engineering educators can better prepare their graduates to perform CHPtD.

Designing to Save Energy

ERIC Educational Resources Information Center

Santamaria, Joseph W.

1977-01-01

While tripling the campus size of Alvin Community College in Texas, architects and engineers cut back on nonessential lighting, recaptured waste heat, insulated everything possible, and let energy considerations dictate the size and shape of the building. (Author/MLF)

Concepts for the design of an antimatter annihilation rocket

NASA Technical Reports Server (NTRS)

Morgan, D. L., Jr.

1982-01-01

Matter-antimatter annihilation is considered for spacecraft propulsion. Annihilation produces considerably more energy per unit mass of propellant than any other known means of energy production. An antimatter annihilation rocket requires several systems and components that are unique to its nature. Among these are an antimatter storage system, a means to extract the antimatter from storage, a system to transport the antimatter to the rocket engine, and the engine wherein annihilation occurs and thrust is produced. Design concepts of these systems and components are presented and discussed.

Air Vehicle Integrated and Technology Research (AVIATR). Task Order 0027: Lighter Than Air (LTA) and Hybrid Aircraft Concept Assessment Tool Development

DTIC Science & Technology

2014-01-01

airships , was taken into consideration when checking cross section dimensions. The top speed chosen to size the engines was 84 knots. The maximum...paramount to understanding the structural design. Engine choice is also critical since long duration missions, typical for airships , heavily...geometry input pages. This may serve as a starting point for a new airship . • Layout is used to define engine , fin and gondola geometry. • Geometry 1

Space Vehicle Terrestrial Environment Design Requirements Guidelines

NASA Technical Reports Server (NTRS)

Johnson, Dale L.; Keller, Vernon W.; Vaughan, William W.

2006-01-01

The terrestrial environment is an important driver of space vehicle structural, control, and thermal system design. NASA is currently in the process of producing an update to an earlier Terrestrial Environment Guidelines for Aerospace Vehicle Design and Development Handbook. This paper addresses the contents of this updated handbook, with special emphasis on new material being included in the areas of atmospheric thermodynamic models, wind dynamics, atmospheric composition, atmospheric electricity, cloud phenomena, atmospheric extremes, and sea state. In addition, the respective engineering design elements are discussed relative to terrestrial environment inputs that require consideration. Specific lessons learned that have contributed to the advancements made in the application and awareness of terrestrial environment inputs for aerospace engineering applications are presented.

The Application of the Human Engineering Modeling and Performance Laboratory for Space Vehicle Ground Processing Tasks at Kennedy Space Center

NASA Technical Reports Server (NTRS)

Woodbury, Sarah K.

2008-01-01

The introduction of United Space Alliance's Human Engineering Modeling and Performance Laboratory began in early 2007 in an attempt to address the problematic workspace design issues that the Space Shuttle has imposed on technicians performing maintenance and inspection operations. The Space Shuttle was not expected to require the extensive maintenance it undergoes between flights. As a result, extensive, costly resources have been expended on workarounds and modifications to accommodate ground processing personnel. Consideration of basic human factors principles for design of maintenance is essential during the design phase of future space vehicles, facilities, and equipment. Simulation will be needed to test and validate designs before implementation.

The application of probabilistic design theory to high temperature low cycle fatigue

NASA Technical Reports Server (NTRS)

Wirsching, P. H.

1981-01-01

Metal fatigue under stress and thermal cycling is a principal mode of failure in gas turbine engine hot section components such as turbine blades and disks and combustor liners. Designing for fatigue is subject to considerable uncertainty, e.g., scatter in cycles to failure, available fatigue test data and operating environment data, uncertainties in the models used to predict stresses, etc. Methods of analyzing fatigue test data for probabilistic design purposes are summarized. The general strain life as well as homo- and hetero-scedastic models are considered. Modern probabilistic design theory is reviewed and examples are presented which illustrate application to reliability analysis of gas turbine engine components.

What Is the Function of a Figurine? Can the Repertory Grid Technique Tell?

ERIC Educational Resources Information Center

Persson, Helena Isakssson

2016-01-01

Teaching design and product development at upper secondary school level in Sweden is a matter of interdisciplinary considerations. Education in product development, at this level, prepares students for further studies and career in engineering or industrial design. Knowledge of artefacts is an important element in the education. In coherence with…

Design for Production Manual. Volume 2. Design/Production Integration

DTIC Science & Technology

1985-12-01

woodworking equipment such as circular saw, cross cut saw, planer / thicknesser and sander. There is considerable use of hand tools in the shop. Joinery inclucies...PROGRAM BY SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS SHIP PRODUCTION COMMITTEE PANEL SP- 4 DESIGN PRODUCTION INTEGRATION CONTRACT DTMA91-82-C...DEC 1985 2. REPORT TYPE N/A 3. DATES COVERED - 4 . TITLE AND SUBTITLE Design for Production Manual Volume 2 of 3 Design/Production

The Navy/NASA Engine Program (NNEP89): Interfacing the program for the calculation of complex Chemical Equilibrium Compositions (CEC)

NASA Technical Reports Server (NTRS)

Gordon, Sanford

1991-01-01

The NNEP is a general computer program for calculating aircraft engine performance. NNEP has been used extensively to calculate the design and off-design (matched) performance of a broad range of turbine engines, ranging from subsonic turboprops to variable cycle engines for supersonic transports. Recently, however, there has been increased interest in applications for which NNEP is not capable of simulating, such as the use of alternate fuels including cryogenic fuels and the inclusion of chemical dissociation effects at high temperatures. To overcome these limitations, NNEP was extended by including a general chemical equilibrium method. This permits consideration of any propellant system and the calculation of performance with dissociation effects. The new extended program is referred to as NNEP89.

Holistic Design for Total Product Well Being

NASA Technical Reports Server (NTRS)

Adams, Chris W.; Hamilton, George S.

2004-01-01

Recent hardware development work at NASA's Marshall Space Flight Center creates and argument for the use of a holistic design approach as opposed to a piece part design approach. A piece part design approach being one where individual pieces are developed to their finished state having to meet certain interface and human engineering requirements without much consideration to the final product as a whole. A holistic design approach being one where the final product is evaluated early and frequently during the design process, and individual parts are developed with consideration to how they interact a whole,and how they interact with the user and environment. Examples from the development of the Materials Science Research Rack - 1 will illustrate: a design failure due to piece part design; a design save, due to a failure of piece part design, but saved by evaluating the design holistically; and a design success due to a holistic design approach.

System Safety and the Unintended Consequence

NASA Technical Reports Server (NTRS)

Watson, Clifford

2012-01-01

The analysis and identification of risks often result in design changes or modification of operational steps. This paper identifies the potential of unintended consequences as an over-looked result of these changes. Examples of societal changes such as prohibition, regulatory changes including mandating lifeboats on passenger ships, and engineering proposals or design changes to automobiles and spaceflight hardware are used to demonstrate that the System Safety Engineer must be cognizant of the potential for unintended consequences as a result of an analysis. Conclusions of the report indicate the need for additional foresight and consideration of the potential effects of analysis-driven design, processing changes, and/or operational modifications.

Design of e-Science platform for biomedical imaging research cross multiple academic institutions and hospitals

NASA Astrophysics Data System (ADS)

Zhang, Jianguo; Zhang, Kai; Yang, Yuanyuan; Ling, Tonghui; Wang, Tusheng; Wang, Mingqing; Hu, Haibo; Xu, Xuemin

2012-02-01

More and more image informatics researchers and engineers are considering to re-construct imaging and informatics infrastructure or to build new framework to enable multiple disciplines of medical researchers, clinical physicians and biomedical engineers working together in a secured, efficient, and transparent cooperative environment. In this presentation, we show an outline and our preliminary design work of building an e-Science platform for biomedical imaging and informatics research and application in Shanghai. We will present our consideration and strategy on designing this platform, and preliminary results. We also will discuss some challenges and solutions in building this platform.

The kinematic Stirling engine as an energy conversion subsystem for paraboloidal dish solar thermal plants

NASA Technical Reports Server (NTRS)

Bowyer, J. M.

1984-01-01

The potential of a suitably designed and economically manufactured Stirling engine as the energy conversion subsystem of a paraboloidal dish-Stirling solar thermal power module was estimated. Results obtained by elementary cycle analyses were shown to match quite well the performance characteristics of an advanced kinematic Stirling engine, the United Stirling P-40, as established by current prototypes of the engine and by a more sophisticated analytic model of its advanced derivative. In addition to performance, brief consideration was given to other Stirling engine criteria such as durability, reliability, and serviceability. Production costs were not considered here.

Effect of pavement texture on tire-road noise.

DOT National Transportation Integrated Search

1975-01-01

Because of the potentially conflicting considerations for cost, durability, environment and safety the design engineer must have information on each such subject on which to base his decisions. The great variety of pavement textures for affecting the...

Introduction to Energy Conservation and Production at Waste Cleanup Sites

EPA Pesticide Factsheets

This issue paper, prepared by EPA's Engineering Forum under the Technical Support Project, provides an overview on the considerations for energy conservation and production during the design and (O&M) phases of waste cleanup projects.

Large eddy simulation applications in gas turbines.

PubMed

Menzies, Kevin

2009-07-28

The gas turbine presents significant challenges to any computational fluid dynamics techniques. The combination of a wide range of flow phenomena with complex geometry is difficult to model in the context of Reynolds-averaged Navier-Stokes (RANS) solvers. We review the potential for large eddy simulation (LES) in modelling the flow in the different components of the gas turbine during a practical engineering design cycle. We show that while LES has demonstrated considerable promise for reliable prediction of many flows in the engine that are difficult for RANS it is not a panacea and considerable application challenges remain. However, for many flows, especially those dominated by shear layer mixing such as in combustion chambers and exhausts, LES has demonstrated a clear superiority over RANS for moderately complex geometries although at significantly higher cost which will remain an issue in making the calculations relevant within the design cycle.

Monitoring Agents for Assisting NASA Engineers with Shuttle Ground Processing

NASA Technical Reports Server (NTRS)

Semmel, Glenn S.; Davis, Steven R.; Leucht, Kurt W.; Rowe, Danil A.; Smith, Kevin E.; Boeloeni, Ladislau

2005-01-01

The Spaceport Processing Systems Branch at NASA Kennedy Space Center has designed, developed, and deployed a rule-based agent to monitor the Space Shuttle's ground processing telemetry stream. The NASA Engineering Shuttle Telemetry Agent increases situational awareness for system and hardware engineers during ground processing of the Shuttle's subsystems. The agent provides autonomous monitoring of the telemetry stream and automatically alerts system engineers when user defined conditions are satisfied. Efficiency and safety are improved through increased automation. Sandia National Labs' Java Expert System Shell is employed as the agent's rule engine. The shell's predicate logic lends itself well to capturing the heuristics and specifying the engineering rules within this domain. The declarative paradigm of the rule-based agent yields a highly modular and scalable design spanning multiple subsystems of the Shuttle. Several hundred monitoring rules have been written thus far with corresponding notifications sent to Shuttle engineers. This chapter discusses the rule-based telemetry agent used for Space Shuttle ground processing. We present the problem domain along with design and development considerations such as information modeling, knowledge capture, and the deployment of the product. We also present ongoing work with other condition monitoring agents.

Advanced Low-Emissions Catalytic-Combustor Program, phase 1. [aircraft gas turbine engines

NASA Technical Reports Server (NTRS)

Sturgess, G. J.

1981-01-01

Six catalytic combustor concepts were defined, analyzed, and evaluated. Major design considerations included low emissions, performance, safety, durability, installations, operations and development. On the basis of these considerations the two most promising concepts were selected. Refined analysis and preliminary design work was conducted on these two concepts. The selected concepts were required to fit within the combustor chamber dimensions of the reference engine. This is achieved by using a dump diffuser discharging into a plenum chamber between the compressor discharge and the turbine inlet, with the combustors overlaying the prediffuser and the rear of the compressor. To enhance maintainability, the outer combustor case for each concept is designed to translate forward for accessibility to the catalytic reactor, liners and high pressure turbine area. The catalytic reactor is self-contained with air-cooled canning on a resilient mounting. Both selected concepts employed integrated engine-starting approaches to raise the catalytic reactor up to operating conditions. Advanced liner schemes are used to minimize required cooling air. The two selected concepts respectively employ fuel-rich initial thermal reaction followed by rapid quench and subsequent fuel-lean catalytic reaction of carbon monoxide, and, fuel-lean thermal reaction of some fuel in a continuously operating pilot combustor with fuel-lean catalytic reaction of remaining fuel in a radially-staged main combustor.

Cell encapsulation in biodegradable hydrogels for tissue engineering applications.

PubMed

Nicodemus, Garret D; Bryant, Stephanie J

2008-06-01

Encapsulating cells in biodegradable hydrogels offers numerous attractive features for tissue engineering, including ease of handling, a highly hydrated tissue-like environment for cell and tissue growth, and the ability to form in vivo. Many properties important to the design of a hydrogel scaffold, such as swelling, mechanical properties, degradation, and diffusion, are closely linked to the crosslinked structure of the hydrogel, which is controlled through a variety of different processing conditions. Degradation may be tuned by incorporating hydrolytically or enzymatically labile segments into the hydrogel or by using natural biopolymers that are susceptible to enzymatic degradation. Because cells are present during the gelation process, the number of suitable chemistries and formulations are limited. In this review, we describe important considerations for designing biodegradable hydrogels for cell encapsulation and highlight recent advances in material design and their applications in tissue engineering.

Integrated optical circuit engineering V; Proceedings of the Meeting, San Diego, CA, Aug. 17-20, 1987

NASA Astrophysics Data System (ADS)

Mentzer, Mark A.

Recent advances in the theoretical and practical design and applications of optoelectronic devices and optical circuits are examined in reviews and reports. Topics discussed include system and market considerations, guided-wave phenomena, waveguide devices, processing technology, lithium niobate devices, and coupling problems. Consideration is given to testing and measurement, integrated optics for fiber-optic systems, optical interconnect technology, and optical computing.

Raw Water Ammonia: Implications on Water Quality, Regulatory Compliance, and Management Strategies

EPA Science Inventory

The objective of the talk will be to present engineering design considerations associated with the biological reduction of ammonia from source water. Also, the application of ion exchange softening to address elevated ammonia is presented.

USSR and Eastern Europe Scientific Abstracts, Electronics and Electrical Engineering, No. 43.

DTIC Science & Technology

1978-11-16

WISOWSKI, JANUSZ; STOLARSKI, EDWARD and CZERWINSKI, ANDRZEJ , Institute of Electronic Technology NPCP [Scientific-Production Center for...PINTER (Mrs DUDAS ), MARTA [Abstract] Some theoretical considerations are presented concerning the design of small coaxial cables with

Creating meaningful learning experiences: Understanding students' perspectives of engineering design

NASA Astrophysics Data System (ADS)

Aleong, Richard James Chung Mun

There is a societal need for design education to prepare holistic engineers with the knowledge, skills, and attitudes to innovate and compete globally. Design skills are paramount to the espoused values of higher education, as institutions of higher learning strive to develop in students the cognitive abilities of critical thinking, problem solving, and creativity. To meet these interests from industry and academia, it is important to advance the teaching and learning of engineering design. This research aims to understand how engineering students learn and think about design, as a way for engineering educators to optimize instructional practice and curriculum development. Qualitative research methodology was used to investigate the meaning that engineering students' ascribe to engineering design. The recruitment of participants and corresponding collection of data occurred in two phases using two different data collection techniques. The first phase involved the distribution of a one-time online questionnaire to all first year, third year, and fourth year undergraduate engineering students at three Canadian Universities. After the questionnaire, students were asked if they would be willing to participate in the second phase of data collection consisting of a personal interview. A total of ten students participated in interviews. Qualitative data analysis procedures were conducted on students' responses from the questionnaire and interviews. The data analysis process consisted of two phases: a descriptive phase to code and categorize the data, followed by an interpretative phase to generate further meaning and relationships. The research findings present a conceptual understanding of students' descriptions about engineering design, structured within two educational orientations: a learning studies orientation and a curriculum studies orientation. The learning studies orientation captured three themes of students' understanding of engineering design: awareness, relevance, and transfer. With this framework of student learning, engineering educators can enhance learning experiences by engaging all three levels of students' understanding. The curriculum studies orientation applied the three holistic elements of curriculum---subject matter, society, and the individual---to conceptualize design considerations for engineering curriculum and teaching practice. This research supports the characterization of students' learning experiences to help educators and students optimize their teaching and learning of design education.

Environmental Analysis

NASA Technical Reports Server (NTRS)

1980-01-01

Burns & McDonnell Engineering's environmental control study is assisted by NASA's Computer Software Management and Information Center's programs in environmental analyses. Company is engaged primarily in design of such facilities as electrical utilities, industrial plants, wastewater treatment systems, dams and reservoirs and aviation installations. Company also conducts environmental engineering analyses and advises clients as to the environmental considerations of a particular construction project. Company makes use of many COSMIC computer programs which have allowed substantial savings.

Evolution of design considerations in complex craniofacial reconstruction using patient-specific implants.

PubMed

Peel, Sean; Bhatia, Satyajeet; Eggbeer, Dominic; Morris, Daniel S; Hayhurst, Caroline

2017-06-01

Previously published evidence has established major clinical benefits from using computer-aided design, computer-aided manufacturing, and additive manufacturing to produce patient-specific devices. These include cutting guides, drilling guides, positioning guides, and implants. However, custom devices produced using these methods are still not in routine use, particularly by the UK National Health Service. Oft-cited reasons for this slow uptake include the following: a higher up-front cost than conventionally fabricated devices, material-choice uncertainty, and a lack of long-term follow-up due to their relatively recent introduction. This article identifies a further gap in current knowledge - that of design rules, or key specification considerations for complex computer-aided design/computer-aided manufacturing/additive manufacturing devices. This research begins to address the gap by combining a detailed review of the literature with first-hand experience of interdisciplinary collaboration on five craniofacial patient case studies. In each patient case, bony lesions in the orbito-temporal region were segmented, excised, and reconstructed in the virtual environment. Three cases translated these digital plans into theatre via polymer surgical guides. Four cases utilised additive manufacturing to fabricate titanium implants. One implant was machined from polyether ether ketone. From the literature, articles with relevant abstracts were analysed to extract design considerations. In all, 19 frequently recurring design considerations were extracted from previous publications. Nine new design considerations were extracted from the case studies - on the basis of subjective clinical evaluation. These were synthesised to produce a design considerations framework to assist clinicians with prescribing and design engineers with modelling. Promising avenues for further research are proposed.

Structural integrity of engineering composite materials: a cracking good yarn.

PubMed

Beaumont, Peter W R; Soutis, Costas

2016-07-13

Predicting precisely where a crack will develop in a material under stress and exactly when in time catastrophic fracture of the component will occur is one the oldest unsolved mysteries in the design and building of large-scale engineering structures. Where human life depends upon engineering ingenuity, the burden of testing to prove a 'fracture safe design' is immense. Fitness considerations for long-life implementation of large composite structures include understanding phenomena such as impact, fatigue, creep and stress corrosion cracking that affect reliability, life expectancy and durability of structure. Structural integrity analysis treats the design, the materials used, and figures out how best components and parts can be joined, and takes service duty into account. However, there are conflicting aims in the complete design process of designing simultaneously for high efficiency and safety assurance throughout an economically viable lifetime with an acceptable level of risk. This article is part of the themed issue 'Multiscale modelling of the structural integrity of composite materials'. © 2016 The Author(s).

Perspectives on knowledge in engineering design

NASA Technical Reports Server (NTRS)

Rasdorf, W. J.

1985-01-01

Various perspectives are given of the knowledge currently used in engineering design, specifically dealing with knowledge-based expert systems (KBES). Constructing an expert system often reveals inconsistencies in domain knowledge while formalizing it. The types of domain knowledge (facts, procedures, judgments, and control) differ from the classes of that knowledge (creative, innovative, and routine). The feasible tasks for expert systems can be determined based on these types and classes of knowledge. Interpretive tasks require reasoning about a task in light of the knowledge available, where generative tasks create potential solutions to be tested against constraints. Only after classifying the domain by type and level can the engineer select a knowledge-engineering tool for the domain being considered. The critical features to be weighed after classification are knowledge representation techniques, control strategies, interface requirements, compatibility with traditional systems, and economic considerations.

Leakage Account for Radial Face Contact Seal in Aircraft Engine Support

NASA Astrophysics Data System (ADS)

Vinogradov, A. S.; Sergeeva, T. V.

2018-01-01

The article is dedicated to the development of a methodology for the radial face contact seal design taking into consideration the supporting elements deformations in different aircraft engine operating modes. Radial face contact seals are popular in the aircraft engines bearing support. However, there are no published leakage calculation methodologies of these seals. Radial face contact seal leakage is determined by the gap clearance in the carbon seal ring split. In turn, the size gap clearance depends on the deformation of the seal assembly parts and from the engine operation. The article shows the leakage detection sequence in the intershaft radial face contact seal of the compressor support for take-off and cruising modes. Evaluated calculated leakage values (2.4 g/s at takeoff and 0.75 g/s at cruising) go with experience in designing seals.

The Systems Engineering Process for Human Support Technology Development

NASA Technical Reports Server (NTRS)

Jones, Harry

2005-01-01

Systems engineering is designing and optimizing systems. This paper reviews the systems engineering process and indicates how it can be applied in the development of advanced human support systems. Systems engineering develops the performance requirements, subsystem specifications, and detailed designs needed to construct a desired system. Systems design is difficult, requiring both art and science and balancing human and technical considerations. The essential systems engineering activity is trading off and compromising between competing objectives such as performance and cost, schedule and risk. Systems engineering is not a complete independent process. It usually supports a system development project. This review emphasizes the NASA project management process as described in NASA Procedural Requirement (NPR) 7120.5B. The process is a top down phased approach that includes the most fundamental activities of systems engineering - requirements definition, systems analysis, and design. NPR 7120.5B also requires projects to perform the engineering analyses needed to ensure that the system will operate correctly with regard to reliability, safety, risk, cost, and human factors. We review the system development project process, the standard systems engineering design methodology, and some of the specialized systems analysis techniques. We will discuss how they could apply to advanced human support systems development. The purpose of advanced systems development is not directly to supply human space flight hardware, but rather to provide superior candidate systems that will be selected for implementation by future missions. The most direct application of systems engineering is in guiding the development of prototype and flight experiment hardware. However, anticipatory systems engineering of possible future flight systems would be useful in identifying the most promising development projects.

Engineering the System and Technical Integration

NASA Technical Reports Server (NTRS)

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

2011-01-01

Approximately 80% of the problems encountered in aerospace systems have been due to a breakdown in technical integration and/or systems engineering. One of the major challenges we face in designing, building, and operating space systems is: how is adequate integration achieved for the systems various functions, parts, and infrastructure? This Contractor Report (CR) deals with part of the problem of how we engineer the total system in order to achieve the best balanced design. We will discuss a key aspect of this question - the principle of Technical Integration and its components, along with management and decision making. The CR will first provide an introduction with a discussion of the Challenges in Space System Design and meeting the challenges. Next is an overview of Engineering the System including Technical Integration. Engineering the System is expanded to include key aspects of the Design Process, Lifecycle Considerations, etc. The basic information and figures used in this CR were presented in a NASA training program for Program and Project Managers Development (PPMD) in classes at Georgia Tech and at Marshall Space Flight Center (MSFC). Many of the principles and illustrations are extracted from the courses we teach for MSFC.

Quickening: Translational design of resorbable synthetic vascular grafts.

PubMed

Stowell, Chelsea E T; Wang, Yadong

2018-08-01

Traditional tissue-engineered vascular grafts have yet to gain wide clinical use. The difficulty of scaling production of these cell- or biologic-based products has hindered commercialization. In situ tissue engineering bypasses such logistical challenges by using acellular resorbable scaffolds. Upon implant, the scaffolds become remodeled by host cells. This review describes the scientific and translational advantages of acellular, synthetic vascular grafts. It surveys in vivo results obtained with acellular synthetics over their fifty years of technological development. Finally, it discusses emerging principles, highlights strategic considerations for designers, and identifies questions needing additional research. Copyright © 2018 Elsevier Ltd. All rights reserved.

Safety considerations in the design and operation of large wind turbines

NASA Technical Reports Server (NTRS)

Reilly, D. H.

1979-01-01

The engineering and safety techniques used to assure the reliable and safe operation of large wind turbine generators utilizing the Mod 2 Wind Turbine System Program as an example is described. The techniques involve a careful definition of the wind turbine's natural and operating environments, use of proven structural design criteria and analysis techniques, an evaluation of potential failure modes and hazards, and use of a fail safe and redundant component engineering philosophy. The role of an effective quality assurance program, tailored to specific hardware criticality, and the checkout and validation program developed to assure system integrity are described.

Radiation Shielding for Nuclear Thermal Propulsion

NASA Technical Reports Server (NTRS)

Caffrey, Jarvis A.

2016-01-01

Design and analysis of radiation shielding for nuclear thermal propulsion has continued at Marshall Space Flight Center. A set of optimization tools are in development, and strategies for shielding optimization will be discussed. Considerations for the concurrent design of internal and external shielding are likely required for a mass optimal shield design. The task of reducing radiation dose to crew from a nuclear engine is considered to be less challenging than the task of thermal mitigation for cryogenic propellant, especially considering the likely implementation of additional crew shielding for protection from solar particles and cosmic rays. Further consideration is thus made for the thermal effects of radiation absorption in cryogenic propellant. Materials challenges and possible methods of manufacturing are also discussed.

The morality of socioscientific issues: Construal and resolution of genetic engineering dilemmas

NASA Astrophysics Data System (ADS)

Sadler, Troy D.; Zeidler, Dana L.

2004-01-01

The ability to negotiate and resolve socioscientific issues has been posited as integral components of scientific literacy. Although philosophers and science educators have argued that socioscientific issues inherently involve moral and ethical considerations, the ultimate arbiters of morality are individual decision-makers. This study explored the extent to which college students construe genetic engineering issues as moral problems. Twenty college students participated in interviews designed to elicit their ideas, reactions, and feelings regarding a series of gene therapy and cloning scenarios. Qualitative analyses revealed that moral considerations were significant influences on decision-making, indicating a tendency for students to construe genetic engineering issues as moral problems. Students engaged in moral reasoning based on utilitarian analyses of consequences as well as the application of principles. Issue construal was also influenced by affective features such as emotion and intuition. In addition to moral considerations, a series of other factors emerged as important dimensions of socioscientific decision-making. These factors included personal experiences, family biases, background knowledge, and the impact of popular culture. The implications for classroom science instruction and future research are discussed.

Design features of fans, blowers, and compressors

NASA Astrophysics Data System (ADS)

Cheremisinoff, N. P.; Cheremisinoff, P. N.

Fan engineering and compression machines are discussed. Basic aspects of fan performance and design are reviewed, and the design and performance characteristics of radial-flow fans, axial-flow fans, and controllable pitch fans are examined in detail. Air-conditioning systems are discussed, and noise, vibration, and mechanical considerations in fans are extensively examined. The thermodynamic principles governing compression machines are reviewed, and piston compressors, rotary compressors, blowers, and centrifugal compressors are discussed.

Engineering Guide for Fire Protection and Detection Systems at Army Ammunition Plants. Volume 1. Selection and Design

DTIC Science & Technology

1980-12-01

type of personnel likely to he using them, (3) the physical environment , (4) health and operational safety considerations. Carefully selected portable...operated apparatus must have the battery and energy-limiting components located outside the hazardous environment , and be so constructed that a direct...designate effect on equipment or personnel), based upon the most severe result of personnel error, procedural deficiencies, environment , design

Quiet aircraft design and operational characteristics

NASA Technical Reports Server (NTRS)

Hodge, Charles G.

1991-01-01

The application of aircraft noise technology to the design and operation of aircraft is discussed. Areas of discussion include the setting of target airplane noise levels, operational considerations and their effect on noise, and the sequencing and timing of the design and development process. Primary emphasis is placed on commercial transport aircraft of the type operated by major airlines. Additionally, noise control engineering of other types of aircraft is briefly discussed.

Preliminary Component Integration Using Rapid Prototyping Techniques

NASA Technical Reports Server (NTRS)

Cooper, Ken; Salvail, Pat; Gordon, Gail (Technical Monitor)

2001-01-01

Rapid prototyping is a very important tool that should be used by both design and manufacturing disciplines during the development of elements for the aerospace industry. It helps prevent lack of adequate communication between design and manufacturing engineers (which could lead to costly errors) through mutual consideration of functional models generated from drawings. Rapid prototyping techniques are used to test hardware for design and material compatibility at Marshall Space Flight Center.

Introduction to human factors considerations in system design

NASA Technical Reports Server (NTRS)

Chapanis, A.

1983-01-01

A definition for human factors or ergonomics and its industrial and domestic application is presented. Human factors engineering, which discovers and applies information about human abilities, limitations, and other characteristics to the design of tools, machines, systems, tasks, jobs, and environments for safe, comfortable, and effective human use, is outlined. The origins of human factors and ergonomics, the philosophy of human factors, goals and objectives, systems development and design, are reviewed.

A Nomographic Methodology for Use in Performance Trade-Off Studies of Parabolic Dish Solar Power Modules

NASA Technical Reports Server (NTRS)

Selcuk, M. K.; Fujita, T.

1984-01-01

A simple graphical method was developed to undertake technical design trade-off studies for individual parabolic dish models comprising a two-axis tracking parabolic dish with a cavity receiver and power conversion assembly at the focal point. The results of these technical studies are then used in performing the techno-economic analyses required for determining appropriate subsystem sizing. Selected graphs that characterize the performance of subsystems within the module were arranged in the form of a nomogram that would enable an investigator to carry out several design trade-off studies. Key performance parameters encompassed in the nomogram include receiver losses, intercept factor, engine rating, and engine efficiency. Design and operation parameters such as concentrator size, receiver type (open or windowed aperture), receiver aperture size, operating temperature of the receiver and engine, engine partial load characteristics, concentrator slope error, and the type of reflector surface, are also included in the graphical solution. Cost considerations are not included.

User engineering: A new look at system engineering

NASA Technical Reports Server (NTRS)

Mclaughlin, Larry L.

1987-01-01

User Engineering is a new System Engineering perspective responsible for defining and maintaining the user view of the system. Its elements are a process to guide the project and customer, a multidisciplinary team including hard and soft sciences, rapid prototyping tools to build user interfaces quickly and modify them frequently at low cost, and a prototyping center for involving users and designers in an iterative way. The main consideration is reducing the risk that the end user will not or cannot effectively use the system. The process begins with user analysis to produce cognitive and work style models, and task analysis to produce user work functions and scenarios. These become major drivers of the human computer interface design which is presented and reviewed as an interactive prototype by users. Feedback is rapid and productive, and user effectiveness can be measured and observed before the system is built and fielded. Requirements are derived via the prototype and baselined early to serve as an input to the architecture and software design.

New shipyard layout design for the preliminary phase & case study for the green field project

NASA Astrophysics Data System (ADS)

Song, Young Joo; Woo, Jong Hun

2013-03-01

For several decades, Asian nations such as Korea, Japan and China have been leading the shipbuilding industry since the decline in Europe and America. However, several developing countries such as India, Brazil, etc. are going to make an entrance into the shipbuilding industry. These developing countries are finding technical partners or information providers because they are in situation of little experiences and technologies. Now, the shipbuilding engineering companies of shipbuilding advanced countries are getting a chance of engineering business against those developing countries. The starting point of this business model is green field project for the construction of new shipyard. This business model is started with a design of the shipyard layout. For the conducting of the shipyard layout design, four kinds of engineering parts are required. Those are civil engineering, building engineering, utility engineering and production layout engineering. Among these parts, production layout engineering is most important because its result is the foundation of the other engineering parts and it determines the shipyard capacity during the shipyard operation lifecycle. Previous researches about the shipyard layout design are out of the range from the business requirements because most research cases are in the tower of ivory, which means that there are little consideration of real ship and shipbuilding operation. In this paper, a shipyard layout design for preliminary phase is conducted for the target of newly planned shipyard at Venezuela of South America with an integrated method that is capable of dealing with actual master data from the shipyard. The layout design method of this paper is differentiated from the previous researches in that the actual product data from the target ship and the actual shipbuilding operation data are used for the required area estimation.

Comparative analysis of the designs and implementation of vehicles based on reactive propulsion proposed during the nineteenth and beginning of the twentieth centuries

NASA Technical Reports Server (NTRS)

Sokolskiy, V. N.

1977-01-01

Examination of the presently known historical scientific literature related to the problem of reactive flight indicates that considerable attention had already been given to the idea of reactive propulsion in the nineteenth century; about thirty designs for reaction flying vehicles were proposed during this period. However, the authors of a majority of the designs limited themselves only to a presentation of a diagram of the engine or an account of the principle of its operation, giving neither plans for its structural development nor precise calculations of the amount of energy required for accomplishing reaction flight. None of these authors considered the reaction flying vehicle as an object of variable mass, their choice of energy sources was extremely random, and the theory of the flight of reaction flying vehicles remained completely undeveloped. Early rocket designs of Nezhdanovsky, Ganswindt, Goddard, Tsiolkovsky, and others are examined and the evolution of liquid-propellant rocket engines, solid-propellant rocket engines, and jet aircraft engines is reviewed.

Design Considerations for Human Rating of Liquid Rocket Engines

NASA Technical Reports Server (NTRS)

Parkinson, Douglas

2010-01-01

I.Human-rating is specific to each engine; a. Context of program/project must be understood. b. Engine cannot be discussed independently from vehicle and mission. II. Utilize a logical combination of design, manufacturing, and test approaches a. Design 1) It is crucial to know the potential ways a system can fail, and how a failure can propagate; 2) Fault avoidance, fault tolerance, DFMR, caution and warning all have roles to play. b. Manufacturing and Assembly; 1) As-built vs. as-designed; 2) Review procedures for assembly and maintenance periodically; and 3) Keep personnel trained and certified. c. There is no substitute for test: 1) Analytical tools are constantly advancing, but still need test data for anchoring assumptions; 2) Demonstrate robustness and explore sensitivities; 3) Ideally, flight will be encompassed by ground test experience. III. Consistency and repeatability is key in production a. Maintain robust processes and procedures for inspection and quality control based upon development and qualification experience; b. Establish methods to "spot check" quality and consistency in parts: 1) Dedicated ground test engines; 2) Random components pulled from the line/lot to go through "enhanced" testing.

Design and analysis of a fuel-efficient single-engine, turboprop-powered, business airplane

NASA Technical Reports Server (NTRS)

Martin, G. L.; Everest, D. E., Jr.; Lovell, W. A.; Price, J. E.; Walkley, K. B.; Washburn, G. F.

1981-01-01

The speed, range, payload, and fuel efficiency of a general aviation airplane powered by one turboprop engine was determined and compared to a twin engine turboprop aircraft. An airplane configuration was developed which can carry six people for a noreserve range of 2,408 km at a cruise speed above 154 m/s, and a cruise altitude of about 9,144 m. The cruise speed is comparable to that of the fastest of the current twin turboprop powered airplanes. It is found that the airplane has a cruise specific range greater than all twin turboprop engine airplanes flying in its speed range and most twin piston engine airplanes flying at considerably slower cruise airspeeds.

Robust Rocket Engine Concept

NASA Technical Reports Server (NTRS)

Lorenzo, Carl F.

1995-01-01

The potential for a revolutionary step in the durability of reusable rocket engines is made possible by the combination of several emerging technologies. The recent creation and analytical demonstration of life extending (or damage mitigating) control technology enables rapid rocket engine transients with minimum fatigue and creep damage. This technology has been further enhanced by the formulation of very simple but conservative continuum damage models. These new ideas when combined with recent advances in multidisciplinary optimization provide the potential for a large (revolutionary) step in reusable rocket engine durability. This concept has been named the robust rocket engine concept (RREC) and is the basic contribution of this paper. The concept also includes consideration of design innovations to minimize critical point damage.

Design of a Heliostat for Centro de Investigaciones de Astronomía (CIDA)

NASA Astrophysics Data System (ADS)

Dávila, L. E.; Barboza, S. J.; Sánchez, G. A.; Della Prugna, F.; Cova, J.; Provenzano, S. E.; Chacón, R. D.

2009-05-01

This paper explains the procedure used in the design of a heliostat to be installed at the headquarters of the Centro de Investigaciones de Astronomía, located in the city of Mérida, Venezuela. The heliostat will be used mainly for educational and public outreach programs, so the design specifications did not require compensation for rotation of the Sun's image at the focal point. The engineering computational tools CAD-CAE were used in order to allow a seamless interaction between the two disciplines involved, Mechanical Engineering and Astronomy. It has also been taken into consideration, as a starting requirement, that all materials be easily available and that all parts, excluding the optics, could be manufactured with the equipment available at the CIDA workshop. These considerations were intended to reduce the cost of the device and to increase the feasibility of construction with limited technological facilities and financial resources. The results obtained by means of the computing tools used were validated through comparison against the analytical calculations. As a result, a robust but low cost heliostat was designed which in the near future will be used to project the Sun's image on a screen for public viewing and student research projects.

Advanced Packaging for VLSI/VHSIC (Very Large Scale Integrated Circuits/Very High Speed Integrated Circuits) Applications: Electrical, Thermal, and Mechanical Considerations - An IR&D Report.

DTIC Science & Technology

1987-11-01

developed that can be used by circuit engineers to extract the maximum performance from the devices on various board technologies including multilayer ceramic...Design guidelines have been developed that can be used by circuit engineers to extract the maxi- mum performance from the devices on various board...25 Attenuation and Dispersion Effects ......................................... 27 Skin Effect

Historical perspective - Viking Mars Lander propulsion

NASA Technical Reports Server (NTRS)

Morrisey, Donald C.

1989-01-01

This paper discusses the Viking 1 and 2 missions to Mars in 1975-1976 and describes the design evolution of the Viking Terminal Descent Rocket Engines responsible for decelerating the Viking Mars Landers during the final portion of their descent from orbit. The Viking Terminal Descent Rocket Engines have twice the thrust of the largest monopropellant hydrazine engine developed previously but weigh considerably less. The engine has 18 nozzles, the capability of 10:1 throttling, is totally sealed until fired, employs no organic unsealed materials, is 100 percent germ free, utilized hydrazine STM-20 as the propellant, and starts at a temperature more than 45 F below the propellant's freezing point.

Ascent performance feasibility for next-generation spacecraft

NASA Astrophysics Data System (ADS)

Mancuso, Salvatore Massimo

This thesis deals with the optimization of the ascent trajectories for single-stage suborbital (SSSO), single-stage-to-orbit (SSTO), and two-stage-to-orbit (TSTO) rocket-powered spacecraft. The maximum payload weight problem has been solved using the sequential gradient-restoration algorithm. For the TSTO case, some modifications to the original version of the algorithm have been necessary in order to deal with discontinuities due to staging and the fact that the functional being minimized depends on interface conditions. The optimization problem is studied for different values of the initial thrust-to-weight ratio in the range 1.3 to 1.6, engine specific impulse in the range 400 to 500 sec, and spacecraft structural factor in the range 0.08 to 0.12. For the TSTO configuration, two subproblems are studied: uniform structural factor between stages and nonuniform structural factor between stages. Due to the regular behavior of the results obtained, engineering approximations have been developed which connect the maximum payload weight to the engine specific impulse and spacecraft structural factor; in turn, this leads to useful design considerations. Also, performance sensitivity to the scale of the aerodynamic drag is studied, and it is shown that its effect on payload weight is relatively small, even for drag changes approaching ± 50%. The main conclusions are that: the design of a SSSO configuration appears to be feasible; the design of a SSTO configuration might be comfortably feasible, marginally feasible, or unfeasible, depending on the parameter values assumed; the design of a TSTO configuration is not only feasible, but its payload appears to be considerably larger than that of a SSTO configuration. Improvements in engine specific impulse and spacecraft structural factor are desirable and crucial for SSTO feasibility; indeed, it appears that aerodynamic improvements do not yield significant improvements in payload weight.

Multi-Objective Optimization of a Turbofan for an Advanced, Single-Aisle Transport

NASA Technical Reports Server (NTRS)

Berton, Jeffrey J.; Guynn, Mark D.

2012-01-01

Considerable interest surrounds the design of the next generation of single-aisle commercial transports in the Boeing 737 and Airbus A320 class. Aircraft designers will depend on advanced, next-generation turbofan engines to power these airplanes. The focus of this study is to apply single- and multi-objective optimization algorithms to the conceptual design of ultrahigh bypass turbofan engines for this class of aircraft, using NASA s Subsonic Fixed Wing Project metrics as multidisciplinary objectives for optimization. The independent design variables investigated include three continuous variables: sea level static thrust, wing reference area, and aerodynamic design point fan pressure ratio, and four discrete variables: overall pressure ratio, fan drive system architecture (i.e., direct- or gear-driven), bypass nozzle architecture (i.e., fixed- or variable geometry), and the high- and low-pressure compressor work split. Ramp weight, fuel burn, noise, and emissions are the parameters treated as dependent objective functions. These optimized solutions provide insight to the ultrahigh bypass engine design process and provide information to NASA program management to help guide its technology development efforts.

Cabin fuselage structural design with engine installation and control system

NASA Technical Reports Server (NTRS)

Balakrishnan, Tanapaal; Bishop, Mike; Gumus, Ilker; Gussy, Joel; Triggs, Mike

1994-01-01

Design requirements for the cabin, cabin system, flight controls, engine installation, and wing-fuselage interface that provide adequate interior volume for occupant seating, cabin ingress and egress, and safety are presented. The fuselage structure must be sufficient to meet the loadings specified in the appropriate sections of Federal Aviation Regulation Part 23. The critical structure must provide a safe life of 10(exp 6) load cycles and 10,000 operational mission cycles. The cabin seating and controls must provide adjustment to account for various pilot physiques and to aid in maintenance and operation of the aircraft. Seats and doors shall not bind or lockup under normal operation. Cabin systems such as heating and ventilation, electrical, lighting, intercom, and avionics must be included in the design. The control system will consist of ailerons, elevator, and rudders. The system must provide required deflections with a combination of push rods, bell cranks, pulleys, and linkages. The system will be free from slack and provide smooth operation without binding. Environmental considerations include variations in temperature and atmospheric pressure, protection against sand, dust, rain, humidity, ice, snow, salt/fog atmosphere, wind and gusts, and shock and vibration. The following design goals were set to meet the requirements of the statement of work: safety, performance, manufacturing and cost. To prevent the engine from penetrating the passenger area in the event of a crash was the primary safety concern. Weight and the fuselage aerodynamics were the primary performance concerns. Commonality and ease of manufacturing were major considerations to reduce cost.

Orbital Maneuvering system design evolution

NASA Technical Reports Server (NTRS)

Gibson, C.; Humphries, C.

1985-01-01

Preliminary design considerations and changes made in the baseline space shuttle orbital maneuvering system (OMS) to reduce cost and weight are detailed. The definition of initial subsystem requirements, trade studies, and design approaches are considered. Design features of the engine, its injector, combustion chamber, nozzle extension and bipropellant valve are illustrated and discussed. The current OMS consists of two identical pods that use nitrogen tetroxide (NTO) and monomethylhydrazine (MMH) propellants to provide 1000 ft/sec of delta velocity for a payload of 65,000 pounds. Major systems are pressurant gas storage and control, propellant storage supply and quantity measurement, and the rocket engine, which includes a bipropellant valve, an injector/thrust chamber, and a nozzle. The subsystem provides orbit insertion, circularization, and on orbit and deorbit capability for the shuttle orbiter.

Design of the advanced regional aircraft, the DART-75

NASA Technical Reports Server (NTRS)

Elliot, Steve; Gislason, Jason; Huffstetler, Mark; Mann, Jon; Withers, Ashley; Zimmerman, Mark

1992-01-01

The need for regional aircraft stems from the problem of hub airport congestion. Regional travel will allow a passenger to commute from one spoke city to another spoke city without entering the congested hub airport. In addition, those people traveling longer routes may begin the flight at home instead of traveling to the hub airport. At this time, there is no American aerospace company that produces a regional transport for under 100 passengers. The intention of the Developmental Advanced Regional Transport (DART-75) is to fill this void with a modern, efficient regional aircraft. This design achieves the efficiency through a number of advanced features including three lifting surfaces, partial composite construction, and an advanced engine design. Efficiency is not the only consideration. Structural integrity, fatigue life, ease of maintenance, passenger comfort and convenience, and environmental aspects must all be considered. These factors force the design team to face many tradeoffs that are studied to find the best solution. The final consideration that cannot be overlooked is that of cost. The DART-75 is a 75-passenger medium-range regional transport intended for spoke-to-spoke, spoke-to-hub, and some hub-to-hub operations. Included are the general descriptions of the structures, weight and balance, stability and control, performance, and engine design.

33 CFR 239.5 - Engineering considerations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Engineering considerations. 239.5 Section 239.5 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF... § 239.5 Engineering considerations. Reports on proposals to provide covered channels shall include a...

33 CFR 239.5 - Engineering considerations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Engineering considerations. 239.5 Section 239.5 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF... § 239.5 Engineering considerations. Reports on proposals to provide covered channels shall include a...

33 CFR 239.5 - Engineering considerations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Engineering considerations. 239.5 Section 239.5 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF... § 239.5 Engineering considerations. Reports on proposals to provide covered channels shall include a...

33 CFR 239.5 - Engineering considerations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Engineering considerations. 239.5 Section 239.5 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF... § 239.5 Engineering considerations. Reports on proposals to provide covered channels shall include a...

33 CFR 239.5 - Engineering considerations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Engineering considerations. 239.5 Section 239.5 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF... § 239.5 Engineering considerations. Reports on proposals to provide covered channels shall include a...

Design Development Test and Evaluation (DDT and E) Considerations for Safe and Reliable Human Rated Spacecraft Systems

NASA Technical Reports Server (NTRS)

Miller, James; Leggett, Jay; Kramer-White, Julie

2008-01-01

A team directed by the NASA Engineering and Safety Center (NESC) collected methodologies for how best to develop safe and reliable human rated systems and how to identify the drivers that provide the basis for assessing safety and reliability. The team also identified techniques, methodologies, and best practices to assure that NASA can develop safe and reliable human rated systems. The results are drawn from a wide variety of resources, from experts involved with the space program since its inception to the best-practices espoused in contemporary engineering doctrine. This report focuses on safety and reliability considerations and does not duplicate or update any existing references. Neither does it intend to replace existing standards and policy.

System design from mission definition to flight validation

NASA Technical Reports Server (NTRS)

Batill, S. M.

1992-01-01

Considerations related to the engineering systems design process and an approach taken to introduce undergraduate students to that process are presented. The paper includes details on a particular capstone design course. This course is a team oriented aircraft design project which requires the students to participate in many phases of the system design process, from mission definition to validation of their design through flight testing. To accomplish this in a single course requires special types of flight vehicles. Relatively small-scale, remotely piloted vehicles have provided the class of aircraft considered in this course.

Biosynthetic engineering of nonribosomal peptide synthetases.

PubMed

Kries, Hajo

2016-09-01

From the evolutionary melting pot of natural product synthetase genes, microorganisms elicit antibiotics, communication tools, and iron scavengers. Chemical biologists manipulate these genes to recreate similarly diverse and potent biological activities not on evolutionary time scales but within months. Enzyme engineering has progressed considerably in recent years and offers new screening, modelling, and design tools for natural product designers. Here, recent advances in enzyme engineering and their application to nonribosomal peptide synthetases are reviewed. Among the nonribosomal peptides that have been subjected to biosynthetic engineering are the antibiotics daptomycin, calcium-dependent antibiotic, and gramicidin S. With these peptides, incorporation of unnatural building blocks and modulation of bioactivities via various structural modifications have been successfully demonstrated. Natural product engineering on the biosynthetic level is not a reliable method yet. However, progress in the understanding and manipulation of biosynthetic pathways may enable the routine production of optimized peptide drugs in the near future. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

Advanced Engineering Environments: Implications for Aerospace Manufacturing

NASA Technical Reports Server (NTRS)

Thomas, D.

2001-01-01

There are significant challenges facing today's aerospace industry. Global competition, more complex products, geographically-distributed design teams, demands for lower cost, higher reliability and safer vehicles, and the need to incorporate the latest technologies quicker all face the developer of aerospace systems. New information technologies offer promising opportunities to develop advanced engineering environments (AEEs) to meet these challenges. Significant advances in the state-of-the-art of aerospace engineering practice are envisioned in the areas of engineering design and analytical tools, cost and risk tools, collaborative engineering, and high-fidelity simulations early in the development cycle. These advances will enable modeling and simulation of manufacturing methods, which will in turn allow manufacturing considerations to be included much earlier in the system development cycle. Significant cost savings, increased quality, and decreased manufacturing cycle time are expected to result. This paper will give an overview of the NASA's Intelligent Synthesis Environment, the agency initiative to develop an AEE, with a focus on the anticipated benefits in aerospace manufacturing.

Computational methods in metabolic engineering for strain design.

PubMed

Long, Matthew R; Ong, Wai Kit; Reed, Jennifer L

2015-08-01

Metabolic engineering uses genetic approaches to control microbial metabolism to produce desired compounds. Computational tools can identify new biological routes to chemicals and the changes needed in host metabolism to improve chemical production. Recent computational efforts have focused on exploring what compounds can be made biologically using native, heterologous, and/or enzymes with broad specificity. Additionally, computational methods have been developed to suggest different types of genetic modifications (e.g. gene deletion/addition or up/down regulation), as well as suggest strategies meeting different criteria (e.g. high yield, high productivity, or substrate co-utilization). Strategies to improve the runtime performances have also been developed, which allow for more complex metabolic engineering strategies to be identified. Future incorporation of kinetic considerations will further improve strain design algorithms. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of Recent Upgrades to the NESS (Nuclear Engine System Simulation) Code

NASA Technical Reports Server (NTRS)

Fittje, James E.; Schnitzler, Bruce G.

2008-01-01

The Nuclear Thermal Rocket (NTR) concept is being evaluated as a potential propulsion technology for exploratory expeditions to the moon, Mars, and beyond. The need for exceptional propulsion system performance in these missions has been documented in numerous studies, and was the primary focus of a considerable effort undertaken during the Rover/NERVA program from 1955 to 1973. The NASA Glenn Research Center is leveraging this past NTR investment in their vehicle concepts and mission analysis studies with the aid of the Nuclear Engine System Simulation (NESS) code. This paper presents the additional capabilities and upgrades made to this code in order to perform higher fidelity NTR propulsion system analysis and design, and a comparison of its results to the Small Nuclear Rocket Engine (SNRE) design.

Status of the Magma Energy Project

NASA Astrophysics Data System (ADS)

Dunn, J. C.

The current magma energy project is assessing the engineering feasibility of extracting thermal energy directly from crustal magma bodies. The estimated size of the U.S. resource (50,000 to 500,000 quads) suggests a considerable potential impact on future power generation. In a previous seven-year study, we concluded that there are no insurmountable barriers that would invalidate the magma energy concept. Several concepts for drilling, energy extraction, and materials survivability were successfully demonstrated in Kilauea Iki lava lake, Hawaii. The present program is addressing the engineering design problems associated with accessing magma bodies and extracting thermal energy for power generation. The normal stages for development of a geothermal resource are being investigated: exploration, drilling and completions, production, and surface power plant design. Current status of the engineering program and future plans are described.

Structural and mechanical design challenges of space shuttle solid rocket boosters separation and recovery subsystems

NASA Technical Reports Server (NTRS)

Woodis, W. R.; Runkle, R. E.

1985-01-01

The design of the space shuttle solid rocket booster (SRB) subsystems for reuse posed some unique and challenging design considerations. The separation of the SRBs from the cluster (orbiter and external tank) at 150,000 ft when the orbiter engines are running at full thrust meant the two SRBs had to have positive separation forces pushing them away. At the same instant, the large attachments that had reacted launch loads of 7.5 million pounds thrust had to be servered. These design considerations dictated the design requirements for the pyrotechnics and separation rocket motors. The recovery and reuse of the two SRBs meant they had to be safely lowered to the ocean, remain afloat, and be owed back to shore. In general, both the pyrotechnic and recovery subsystems have met or exceeded design requirements. In twelve vehicles, there has only been one instance where the pyrotechnic system has failed to function properly.

Guidance, Navigation and Control (GN&C): Best Practices for Human-Rated Spacecraft Systems

NASA Technical Reports Server (NTRS)

Lebsock, Ken; West, John

2008-01-01

In 2007 the NESC completed an in-depth assessment to identify, define and document engineering considerations for the Design Development Test and Evaluation (DDT&E) of human-rated spacecraft systems. This study had been requested by the Astronaut Office at JSC to help them to better understand what is required to ensure safe, robust, and reliable human-rated spacecraft systems. The 22 GN&C engineering Best Practices described in this paper are a condensed version of what appears in the NESC Technical Report. These Best Practices cover a broad range from fundamental system architectural considerations to more specific aspects (e.g., stability margin recommendations) of GN&C system design and development. 15 of the Best Practices address the early phases of a GN&C System development project and the remaining 7 deal with the later phases. Some of these Best Practices will cross-over between both phases. We recognize that this set of GN&C Best Practices will not be universally applicable to all projects and mission applications.

Life prediction technologies for aeronautical propulsion systems

NASA Technical Reports Server (NTRS)

Mcgaw, Michael A.

1987-01-01

Fatigue and fracture problems continue to occur in aeronautical gas turbine engines. Components whose useful life is limited by these failure modes include turbine hot-section blades, vanes and disks. Safety considerations dictate that catastrophic failures be avoided, while economic considerations dictate that noncatastrophic failures occur as infrequently as possible. The design decision is therefore in making the tradeoff between engine performance and durability. The NASA Lewis Research Center has contributed to the aeropropulsion industry in the areas of life prediction technology for 30 years, developing creep and fatigue life prediction methodologies for hot-section materials. Emphasis is placed on the development of methods capable of handling both thermal and mechanical fatigue under severe environments. Recent accomplishments include the development of more accurate creep-fatigue life prediction methods such as the total strain version of Lewis' Strainrange Partitioning (SRP) and the HOST-developed Cyclic Damage Accumulation (CDA) model. Other examples include the Double Damage Curve Approach (DDCA), which provides greatly improved accuracy for cumulative fatigue design rules.

ERISTAR: Earth Resources Information Storage, Transformation, Analysis, and Retrieval

NASA Technical Reports Server (NTRS)

1972-01-01

The National Aeronautics and Space Administration (NASA) and the American Society for Engineering Education (ASEE) have sponsored faculty fellowship programs in systems engineering design for the past several years. During the summer of 1972 four such programs were conducted by NASA, with Auburn University cooperating with Marshall Space Flight Center (MSFC). The subject for the Auburn-MSFC design group was ERISTAR, an acronym for Earth Resources Information Storage, Transformation, Analysis and Retrieval, which represents an earth resources information management network of state information centers administered by the respective states and linked to federally administered regional centers and a national center. The considerations for serving the users and the considerations that must be given to processing data from a variety of sources are described. The combination of these elements into a national network is discussed and an implementation plan is proposed for a prototype state information center. The compatibility of the proposed plan with the Department of Interior plan, RALI, is indicated.

Flight evaluation of an extended engine life mode on an F-15 airplane

NASA Technical Reports Server (NTRS)

Myers, Lawrence P.; Conners, Timothy R.

1992-01-01

An integrated flight and propulsion control system designed to reduce the rate of engine deterioration was developed and evaluated in flight on the NASA Dryden F-15 research aircraft. The extended engine life mode increases engine pressure ratio while reducing engine airflow to lower the turbine temperature at constant thrust. The engine pressure ratio uptrim is modulated in real time based on airplane maneuver requirements, flight conditions, and engine information. The extended engine life mode logic performed well, significantly reducing turbine operating temperature. Reductions in fan turbine inlet temperature of up to 80 F were obtained at intermediate power and up to 170 F at maximum augmented power with no appreciable loss in thrust. A secondary benefit was the considerable reduction in thrust-specific fuel consumption. The success of the extended engine life mode is one example of the advantages gained from integrating aircraft flight and propulsion control systems.

Study of solid rocket motors for a space shuttle booster. Volume 2, book 1: Analysis and design

NASA Technical Reports Server (NTRS)

1972-01-01

An analysis of the factors which determined the selection of the solid rocket propellant engines for the space shuttle booster is presented. The 156 inch diameter, parallel burn engine was selected because of its transportability, cost effectiveness, and reliability. Other factors which caused favorable consideration are: (1) recovery and reuse are feasible and offer substantial cost savings, (2) abort can be easily accomplished. and (3) ecological effects are acceptable.

Systems engineering aspects of a preliminary conceptual design of the space station environmental control and life support system

NASA Technical Reports Server (NTRS)

Lin, C. H.; Meyer, M. S.

1983-01-01

The systems engineering aspects of developing a conceptual design of the Space Station Environmental Control and Life Support System (ECLSS) are discussed. Topics covered include defining system requirements and groundrules for approach, formulating possible cycle closure options, and establishing a system-level mass balance on the essential materials processed in oxygen and water cycles. Consideration is also given to the performance of a system trade-off study to determine the best degree of cycle closure for the ECLSS, and the construction of a conceptual design of the ECLSS with subsystem performance specifications and candidate concepts. For the optimum balance between development costs, technological risks, and resupply penalties, a partially closed cycle ECLSS option is suggested.

Low Conductivity Thermal Barrier Coatings

NASA Technical Reports Server (NTRS)

Zhu, Dong-Ming

2005-01-01

Thermal barrier coatings will be more aggressively designed to protect gas turbine engine hot-section components in order to meet future engine higher fuel efficiency and lower emission goals. In this presentation, thermal barrier coating development considerations and requirements will be discussed. An experimental approach is established to monitor in real time the thermal conductivity of the coating systems subjected to high-heat-flux, steady-state and cyclic temperature gradients. Advanced low conductivity thermal barrier coatings have also been developed using a multi-component defect clustering approach, and shown to have improved thermal stability. The durability and erosion resistance of low conductivity thermal barrier coatings have been improved utilizing advanced coating architecture design, composition optimization, in conjunction with more sophisticated modeling and design tools.

USSR Report, Engineering and Equipment

DTIC Science & Technology

1987-01-22

savings were to be considerable: the designers and manufacturers promised an hourly output of almost twice that of the old conveyor . It is easy to...superficialities than with the effec- tiveness of their designs . NPO VTTIIlitmash transfers technical documentation for series production of new...accumulation of articles on the conveyor or when using a robot, transfer of articles from the conveyor to ceramic plates of the furnace for baking

Aspects of the BPRIM Language for Risk Driven Process Engineering

NASA Astrophysics Data System (ADS)

Sienou, Amadou; Lamine, Elyes; Pingaud, Hervé; Karduck, Achim

Nowadays organizations are exposed to frequent changes in business environment requiring continuous alignment of business processes on business strategies. This agility requires methods promoted in enterprise engineering approaches. Risk consideration in enterprise engineering is getting important since the business environment is becoming more and more competitive and unpredictable. Business processes are subject to the same quality requirements as material and human resources. Thus, process management is supposed to tackle value creation challenges but also the ones related to value preservation. Our research considers risk driven business process design as an integral part of enterprise engineering. A graphical modelling language for risk driven business process engineering was introduced in former research. This paper extends the language and handles questions related to modelling risk in organisational context.

The potential for CMCs to replace superalloys in engine exhaust ducts

NASA Astrophysics Data System (ADS)

Roth, Richard; Clark, Joel P.; Field, Frank R.

1994-01-01

The Materials Systems Laboratory at the Massachusetts Institute of Technology has conducted research to develop decision tools that can facilitate materials selection and provide a deeper understanding of the design tradeoffs that occur when choosing among advanced aerospace materials for high-temperature applications. As an illustration of the use of these tools, this paper describes research done to evaluate the material alternatives currently under consideration for exhaust ducts in aircraft gas turbine engines. Although nickel-based superalloys currently prevail for this application, the increasing temperatures of modern engines are necessitating the usage of higher temperature materials.

Materials for Liquid Propulsion Systems. Chapter 12

NASA Technical Reports Server (NTRS)

Halchak, John A.; Cannon, James L.; Brown, Corey

2016-01-01

Earth to orbit launch vehicles are propelled by rocket engines and motors, both liquid and solid. This chapter will discuss liquid engines. The heart of a launch vehicle is its engine. The remainder of the vehicle (with the notable exceptions of the payload and guidance system) is an aero structure to support the propellant tanks which provide the fuel and oxidizer to feed the engine or engines. The basic principle behind a rocket engine is straightforward. The engine is a means to convert potential thermochemical energy of one or more propellants into exhaust jet kinetic energy. Fuel and oxidizer are burned in a combustion chamber where they create hot gases under high pressure. These hot gases are allowed to expand through a nozzle. The molecules of hot gas are first constricted by the throat of the nozzle (de-Laval nozzle) which forces them to accelerate; then as the nozzle flares outwards, they expand and further accelerate. It is the mass of the combustion gases times their velocity, reacting against the walls of the combustion chamber and nozzle, which produce thrust according to Newton's third law: for every action there is an equal and opposite reaction. Solid rocket motors are cheaper to manufacture and offer good values for their cost. Liquid propellant engines offer higher performance, that is, they deliver greater thrust per unit weight of propellant burned. They also have a considerably higher thrust to weigh ratio. Since liquid rocket engines can be tested several times before flight, they have the capability to be more reliable, and their ability to shut down once started provides an extra margin of safety. Liquid propellant engines also can be designed with restart capability to provide orbital maneuvering capability. In some instances, liquid engines also can be designed to be reusable. On the solid side, hybrid solid motors also have been developed with the capability to stop and restart. Solid motors are covered in detail in chapter 11. Liquid rocket engine operational factors can be described in terms of extremes: temperatures ranging from that of liquid hydrogen (-423 F) to 6000 F hot gases; enormous thermal shock (7000 F/sec); large temperature differentials between contiguous components; reactive propellants; extreme acoustic environments; high rotational speeds for turbo machinery and extreme power densities. These factors place great demands on materials selection and each must be dealt with while maintaining an engine of the lightest possible weight. This chapter will describe the design considerations for the materials used in the various components of liquid rocket engines and provide examples of usage and experiences in each.

Control-Relevant Modeling, Analysis, and Design for Scramjet-Powered Hypersonic Vehicles

NASA Technical Reports Server (NTRS)

Rodriguez, Armando A.; Dickeson, Jeffrey J.; Sridharan, Srikanth; Benavides, Jose; Soloway, Don; Kelkar, Atul; Vogel, Jerald M.

2009-01-01

Within this paper, control-relevant vehicle design concepts are examined using a widely used 3 DOF (plus flexibility) nonlinear model for the longitudinal dynamics of a generic carrot-shaped scramjet powered hypersonic vehicle. Trade studies associated with vehicle/engine parameters are examined. The impact of parameters on control-relevant static properties (e.g. level-flight trimmable region, trim controls, AOA, thrust margin) and dynamic properties (e.g. instability and right half plane zero associated with flight path angle) are examined. Specific parameters considered include: inlet height, diffuser area ratio, lower forebody compression ramp inclination angle, engine location, center of gravity, and mass. Vehicle optimizations is also examined. Both static and dynamic considerations are addressed. The gap-metric optimized vehicle is obtained to illustrate how this control-centric concept can be used to "reduce" scheduling requirements for the final control system. A classic inner-outer loop control architecture and methodology is used to shed light on how specific vehicle/engine design parameter selections impact control system design. In short, the work represents an important first step toward revealing fundamental tradeoffs and systematically treating control-relevant vehicle design.

Sample environment for neutron scattering measurements of internal stresses in engineering materials in the temperature range of 6 K to 300 K.

PubMed

Kirichek, O; Timms, J D; Kelleher, J F; Down, R B E; Offer, C D; Kabra, S; Zhang, S Y

2017-02-01

Internal stresses in materials have a considerable effect on material properties including strength, fracture toughness, and fatigue resistance. The ENGIN-X beamline is an engineering science facility at ISIS optimized for the measurement of strain and stress using the atomic lattice planes as a strain gauge. Nowadays, the rapidly rising interest in the mechanical properties of engineering materials at low temperatures has been stimulated by the dynamic development of the cryogenic industry and the advanced applications of the superconductor technology. Here we present the design and discuss the test results of a new cryogenic sample environment system for neutron scattering measurements of internal stresses in engineering materials under a load of up to 100 kN and in the temperature range of 6 K to 300 K. Complete cooling of the system starting from the room temperature down to the base temperature takes around 90 min. Understanding of internal stresses in engineering materials at cryogenic temperatures is vital for the modelling and designing of cutting-edge superconducting magnets and other superconductor based applications.

Sample environment for neutron scattering measurements of internal stresses in engineering materials in the temperature range of 6 K to 300 K

NASA Astrophysics Data System (ADS)

Kirichek, O.; Timms, J. D.; Kelleher, J. F.; Down, R. B. E.; Offer, C. D.; Kabra, S.; Zhang, S. Y.

2017-02-01

Internal stresses in materials have a considerable effect on material properties including strength, fracture toughness, and fatigue resistance. The ENGIN-X beamline is an engineering science facility at ISIS optimized for the measurement of strain and stress using the atomic lattice planes as a strain gauge. Nowadays, the rapidly rising interest in the mechanical properties of engineering materials at low temperatures has been stimulated by the dynamic development of the cryogenic industry and the advanced applications of the superconductor technology. Here we present the design and discuss the test results of a new cryogenic sample environment system for neutron scattering measurements of internal stresses in engineering materials under a load of up to 100 kN and in the temperature range of 6 K to 300 K. Complete cooling of the system starting from the room temperature down to the base temperature takes around 90 min. Understanding of internal stresses in engineering materials at cryogenic temperatures is vital for the modelling and designing of cutting-edge superconducting magnets and other superconductor based applications.

Design of 3D-Printed Titanium Compliant Mechanisms

NASA Technical Reports Server (NTRS)

Merriam, Ezekiel G.; Jones, Jonathan E.; Howell, Larry L.

2014-01-01

This paper describes 3D-printed titanium compliant mechanisms for aerospace applications. It is meant as a primer to help engineers design compliant, multi-axis, printed parts that exhibit high performance. Topics covered include brief introductions to both compliant mechanism design and 3D printing in titanium, material and geometry considerations for 3D printing, modeling techniques, and case studies of both successful and unsuccessful part geometries. Key findings include recommended flexure geometries, minimum thicknesses, and general design guidelines for compliant printed parts that may not be obvious to the first time designer.

FAST FLUX TEST FACILITY CONCEPTUAL FACILTY DESIGN DESCRIPTION FOR THE INERT GAS CELL EXAMINATION FACILITY NO. 71

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

None

1968-12-12

The purpose of this Conceptual Facility Design Description (CFDD) is to provide a technical description of the Inert Gas Cell Examination Facility such that agreement with RDT on a Conceptual Design can be reached . The CFDD also serves to establish a common understanding of the facility concept among all responsible FFTF Project parties including the Architect Engineer and Reactor Designer. Included are functions and design requirements, a physical description of the facility, safety considerations, principles of operation, and maintenance principles.

Optical systems engineering - A tutorial

NASA Technical Reports Server (NTRS)

Wyman, C. L.

1979-01-01

The paper examines the use of the systems engineering approach in the design of optical systems, noting that the use of such an approach which involves an integrated interdisciplinary approach to the development of systems is most appropriate for optics. It is shown that the high precision character of optics leads to complex and subtle effects on optical system performance, resulting from structural, thermal dynamical, control system, and manufacturing and assembly considerations. Attention is given to communication problems that often occur among users and optical engineers due to the unique factors of optical systems. It is concluded that it is essential that the optics community provide leadership to resolve communication problems and fully formalize the field of optical systems engineering.

NERVA-Derived Nuclear Thermal Propulsion Dual Mode Operation

NASA Astrophysics Data System (ADS)

Zweig, Herbert R.; Hundal, Rolv

1994-07-01

Generation of electrical power using the nuclear heat source of a NERVA-derived nuclear thermal rocket engine is presented. A 111,200 N thrust engine defined in a study for NASA-LeRC in FY92 is the reference engine for a three-engine vehicle for which a 50 kWe capacity is required. Processes are described for energy extraction from the reactor and for converting the energy to electricity. The tie tubes which support the reactor fuel elements are the source of thermal energy. The study focuses on process systems using Stirling cycle energy conversion operating at 980 K and an alternate potassium-Rankine system operating at 1,140 K. Considerations are given of the effect of the power production on turbopump operation, ZrH moderator dissociation, creep strain in the tie tubes, hydrogen permeation through the containment materials, requirements for a backup battery system, and the effects of potential design changes on reactor size and criticality. Nuclear considerations include changing tie tube materials to TZM, changing the moderator to low vapor-pressure yttrium hydride, and changing the fuel form from graphite matrix to a carbon-carbide composite.

Application of the Tool for Turbine Engine Closed-loop Transient Analysis (TTECTrA) for Dynamic Systems Analysis

NASA Technical Reports Server (NTRS)

Csank, Jeffrey; Zinnecker, Alicia

2014-01-01

Systems analysis involves steady-state simulations of combined components to evaluate the steady-state performance, weight, and cost of a system; dynamic considerations are not included until later in the design process. The Dynamic Systems Analysis task, under NASAs Fixed Wing project, is developing the capability for assessing dynamic issues at earlier stages during systems analysis. To provide this capability the Tool for Turbine Engine Closed-loop Transient Analysis (TTECTrA) has been developed to design a single flight condition controller (defined as altitude and Mach number) and, ultimately, provide an estimate of the closed-loop performance of the engine model. This tool has been integrated with the Commercial Modular Aero-Propulsion System Simulation 40,000(CMAPSS40k) engine model to demonstrate the additional information TTECTrA makes available for dynamic systems analysis. This dynamic data can be used to evaluate the trade-off between performance and safety, which could not be done with steady-state systems analysis data. TTECTrA has been designed to integrate with any turbine engine model that is compatible with the MATLABSimulink (The MathWorks, Inc.) environment.

Application of the Tool for Turbine Engine Closed-loop Transient Analysis (TTECTrA) for Dynamic Systems Analysis

NASA Technical Reports Server (NTRS)

Csank, Jeffrey Thomas; Zinnecker, Alicia Mae

2014-01-01

Systems analysis involves steady-state simulations of combined components to evaluate the steady-state performance, weight, and cost of a system; dynamic considerations are not included until later in the design process. The Dynamic Systems Analysis task, under NASAs Fixed Wing project, is developing the capability for assessing dynamic issues at earlier stages during systems analysis. To provide this capability the Tool for Turbine Engine Closed-loop Transient Analysis (TTECTrA) has been developed to design a single flight condition controller (defined as altitude and Mach number) and, ultimately, provide an estimate of the closed-loop performance of the engine model. This tool has been integrated with the Commercial Modular Aero-Propulsion System Simulation 40,000 (CMAPSS 40k) engine model to demonstrate the additional information TTECTrA makes available for dynamic systems analysis. This dynamic data can be used to evaluate the trade-off between performance and safety, which could not be done with steady-state systems analysis data. TTECTrA has been designed to integrate with any turbine engine model that is compatible with the MATLAB Simulink (The MathWorks, Inc.) environment.

Human Factors Design Principles for Instrument Approach Procedure Charts. Volume 1. Readability

DTIC Science & Technology

1992-08-01

discovery of mechanical type (Spencer, 1969). Not surprisingly, there is a substantial body of research and accepted practice that addresses...Swey for Automotive Engieer ARP4032 (April, 1988). Human engineering considerations in the application of cobr to electronic aircmjl dLspkp. Warrenlale

Integrated optical circuit engineering IV; Proceedings of the Meeting, Cambridge, MA, Sept. 16, 17, 1986

NASA Astrophysics Data System (ADS)

Mentzer, Mark A.; Sriram, S.

The design and implementation of integrated optical circuits are discussed in reviews and reports. Topics addressed include lithium niobate devices, silicon integrated optics, waveguide phenomena, coupling considerations, processing technology, nonlinear guided-wave optics, integrated optics for fiber systems, and systems considerations and applications. Also included are eight papers and a panel discussion from an SPIE conference on the processing of guided-wave optoelectronic materials (held in Los Angeles, CA, on January 21-22, 1986).

Design consideration for a nuclear electric propulsion system

NASA Technical Reports Server (NTRS)

Phillips, W. M.; Pawlik, E. V.

1978-01-01

A study is currently underway to design a nuclear electric propulsion vehicle capable of performing detailed exploration of the outer-planets. Primary emphasis is on the power subsystem. Secondary emphasis includes integration into a spacecraft, and integration with the thrust subsystem and science package or payload. The results of several design iterations indicate an all-heat-pipe system offers greater reliability, elimination of many technology development areas and a specific weight of under 20 kg/kWe at the 400 kWe power level. The system is compatible with a single Shuttle launch and provides greater safety than could be obtained with designs using pumped liquid metal cooling. Two configurations, one with the reactor and power conversion forward on the spacecraft with the ion engines aft and the other with reactor, power conversion and ion engines aft were selected as dual baseline designs based on minimum weight, minimum required technology development and maximum growth potential and flexibility.

System Noise Assessment of Blended-Wing-Body Aircraft With Open Rotor Propulsion

NASA Technical Reports Server (NTRS)

Guo, Yueping; Thomas, Russell H.

2015-01-01

An aircraft system noise study is presented for the Blended-Wing-Body (BWB) aircraft concept with three open rotor engines mounted on the upper surface of the airframe. It is shown that for such an aircraft, the cumulative Effective Perceived Noise Level (EPNL) is about 24 dB below the current aircraft noise regulations of Stage 4. While this makes the design acoustically viable in meeting the regulatory requirements, even with the consideration of more stringent noise regulations of a possible Stage 5 in the next decade or so, the design will likely meet stiff competitions from aircraft with turbofan engines. It is shown that the noise levels of the BWB design are held up by the inherently high noise levels of the open rotor engines and the limitation on the shielding benefit due to the practical design constraint on the engine location. Furthermore, it is shown that the BWB design has high levels of noise from the main landing gear, due to their exposure to high speed flow at the junction between the center body and outer wing. These are also the reasons why this baseline BWB design does not meet the NASA N+2 noise goal of 42 dB below Stage 4. To identify approaches that may further reduce noise, parametric studies are also presented, including variations in engine location, vertical tail and elevon variations, and airframe surface acoustic liner treatment effect. These have the potential to further reduce noise but they are only at the conceptual stage.

Statistical analysis of Turbine Engine Diagnostic (TED) field test data

NASA Astrophysics Data System (ADS)

Taylor, Malcolm S.; Monyak, John T.

1994-11-01

During the summer of 1993, a field test of turbine engine diagnostic (TED) software, developed jointly by U.S. Army Research Laboratory and the U.S. Army Ordnance Center and School, was conducted at Fort Stuart, GA. The data were collected in conformance with a cross-over design, some of whose considerations are detailed. The initial analysis of the field test data was exploratory, followed by a more formal investigation. Technical aspects of the data analysis insights that were elicited are reported.

Photovoltaic power system reliability considerations

NASA Technical Reports Server (NTRS)

Lalli, V. R.

1980-01-01

This paper describes an example of how modern engineering and safety techniques can be used to assure the reliable and safe operation of photovoltaic power systems. This particular application was for a solar cell power system demonstration project in Tangaye, Upper Volta, Africa. The techniques involve a definition of the power system natural and operating environment, use of design criteria and analysis techniques, an awareness of potential problems via the inherent reliability and FMEA methods, and use of a fail-safe and planned spare parts engineering philosophy.

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.

Eagle RTS: A design of a regional transport

NASA Technical Reports Server (NTRS)

Bryer, Paul; Buckles, Jon; Lemke, Paul; Peake, Kirk

1992-01-01

The Eagle RTS (Regional Transport System) is a 66-passenger aircraft designed to satisfy the need for accessible and economical regional travel. The first design objective for the Eagle RTS is safety. Safety results primarily from avoidance of the hub airport air traffic, implementation of anti-stall characteristics by tailoring the canard, and proper positioning of the engines for blade shedding. To provide the most economical aircraft, the Eagle RTS will use existing technology to lower production and maintenance costs by decreasing the amount of new training required. In selecting the propulsion system, the effects on the environment were a main consideration. Two advantages of turbo-prop engines are the high fuel efficiency and low noise levels produced by this type of engine. This ensures the aircraft's usage during times of rising fuel costs and growing aircraft noise restrictions. The design of the Eagle RTS is for spoke-to-spoke transportation. It must be capable of landing on shorter runways and have speeds comparable to that of the larger aircraft to make its service beneficial to the airlines. With the use of turbo-prop engines and high lift devices, the Eagle RTS is highly adaptable to regional airports. The design topics discussed include: aerodynamics, stability, structures and materials, propulsion, and cost.

Design of a Computer-Adaptive Test to Measure English Literacy and Numeracy in the Singapore Workforce: Considerations, Benefits, and Implications

ERIC Educational Resources Information Center

Jacobsen, Jared; Ackermann, Richard; Eguez, Jane; Ganguli, Debalina; Rickard, Patricia; Taylor, Linda

2011-01-01

A computer adaptive test (CAT) is a delivery methodology that serves the larger goals of the assessment system in which it is embedded. A thorough analysis of the assessment system for which a CAT is being designed is critical to ensure that the delivery platform is appropriate and addresses all relevant complexities. As such, a CAT engine must be…

Evaluation of indeterminacy of initial data for cad system of electric engine suspension

NASA Astrophysics Data System (ADS)

Antipin, D. Ya; Izmerov, O. V.; Shorokhov, S. G.; Nadtochey, D. G.

2018-03-01

The research of the variants of the suspension of the traction electric motor of diesel locomotives was performed. It was found that the method of designing the suspension does not take into consideration the possible changes of the characteristics of the parts in operation conditions. Variants of the suspension design were proposed and patented, which provide the work reliability despite the operating conditions.

A Historical Systems Study of Liquid Rocket Engine Throttling Capabilities

NASA Technical Reports Server (NTRS)

Betts, Erin M.; Frederick, Robert A., Jr.

2010-01-01

This is a comprehensive systems study to examine and evaluate throttling capabilities of liquid rocket engines. The focus of this study is on engine components, and how the interactions of these components are considered for throttling applications. First, an assessment of space mission requirements is performed to determine what applications require engine throttling. A background on liquid rocket engine throttling is provided, along with the basic equations that are used to predict performance. Three engines are discussed that have successfully demonstrated throttling. Next, the engine system is broken down into components to discuss special considerations that need to be made for engine throttling. This study focuses on liquid rocket engines that have demonstrated operational capability on American space launch vehicles, starting with the Apollo vehicle engines and ending with current technology demonstrations. Both deep throttling and shallow throttling engines are discussed. Boost and sustainer engines have demonstrated throttling from 17% to 100% thrust, while upper stage and lunar lander engines have demonstrated throttling in excess of 10% to 100% thrust. The key difficulty in throttling liquid rocket engines is maintaining an adequate pressure drop across the injector, which is necessary to provide propellant atomization and mixing. For the combustion chamber, cooling can be an issue at low thrust levels. For turbomachinery, the primary considerations are to avoid cavitation, stall, surge, and to consider bearing leakage flows, rotordynamics, and structural dynamics. For valves, it is necessary to design valves and actuators that can achieve accurate flow control at all thrust levels. It is also important to assess the amount of nozzle flow separation that can be tolerated at low thrust levels for ground testing.

Pore size engineering applied to the design of separators for nickel-hydrogen cells and batteries

NASA Technical Reports Server (NTRS)

Abbey, K. M.; Britton, D. L.

1983-01-01

Pore size engineering in starved alkaline multiplate cells involves adopting techniques to widen the volume tolerance of individual cells. Separators with appropriate pore size distributions and wettability characteristics (capillary pressure considerations) to have wider volume tolerances and an ability to resist dimensional changes in the electrodes were designed. The separators studied for potential use in nickel-hydrogen cells consist of polymeric membranes as well as inorganic microporous mats. In addition to standard measurements, the resistance and distribution of electrolyte as a function of total cell electrolyte content were determined. New composite separators consisting of fibers, particles and/or binders deposited on Zircar cloth were developed in order to engineer the proper capillary pressure characteristics in the separator. These asymmetric separators were prepared from a variety of fibers, particles and binders.

Neurosecurity: security and privacy for neural devices.

PubMed

Denning, Tamara; Matsuoka, Yoky; Kohno, Tadayoshi

2009-07-01

An increasing number of neural implantable devices will become available in the near future due to advances in neural engineering. This discipline holds the potential to improve many patients' lives dramatically by offering improved-and in some cases entirely new-forms of rehabilitation for conditions ranging from missing limbs to degenerative cognitive diseases. The use of standard engineering practices, medical trials, and neuroethical evaluations during the design process can create systems that are safe and that follow ethical guidelines; unfortunately, none of these disciplines currently ensure that neural devices are robust against adversarial entities trying to exploit these devices to alter, block, or eavesdrop on neural signals. The authors define "neurosecurity"-a version of computer science security principles and methods applied to neural engineering-and discuss why neurosecurity should be a critical consideration in the design of future neural devices.

Stainless steel blanket concept for tokamaks

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

Karbowski, J.S.; Lee, A.Y.; Prevenslik, T.V.

1979-01-25

The purpose of this joint ORNL/Westinghouse Program is to develop a design concept for a tokamak reactor blanket system which satisfies engineering requirements for a utility environment. While previous blanket studies have focused primarily on performance issues (thermal, neutronic, and structural), this study has emphasized consideration of reliability, fabricability, and lifetime.

Swimming Pools.

ERIC Educational Resources Information Center

Ministry of Housing and Local Government, London (England).

Technical and engineering data are set forth on the design and construction of swimming pools. Consideration is given to site selection, pool construction, the comparative merits of combining open air and enclosed pools, and alternative uses of the pool. Guidelines are presented regarding--(1) pool size and use, (2) locker and changing rooms, (3)…

Do We Need to Design Course-Based Undergraduate Research Experiences for Authenticity?

ERIC Educational Resources Information Center

Rowland, Susan; Pedwell, Rhianna; Lawrie, Gwen; Lovie-Toon, Joseph; Hung, Yu

2016-01-01

The recent push for more authentic teaching and learning in science, technology, engineering, and mathematics indicates a shared agreement that undergraduates require greater exposure to professional practices. There is considerable variation, however, in how "authentic" science education is defined. In this paper we present our…

Proteomics in the genome engineering era.

PubMed

Vandemoortele, Giel; Gevaert, Kris; Eyckerman, Sven

2016-01-01

Genome engineering experiments used to be lengthy, inefficient, and often expensive, preventing a widespread adoption of such experiments for the full assessment of endogenous protein functions. With the revolutionary clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 technology, genome engineering became accessible to the broad life sciences community and is now implemented in several research areas. One particular field that can benefit significantly from this evolution is proteomics where a substantial impact on experimental design and general proteome biology can be expected. In this review, we describe the main applications of genome engineering in proteomics, including the use of engineered disease models and endogenous epitope tagging. In addition, we provide an overview on current literature and highlight important considerations when launching genome engineering technologies in proteomics workflows. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Performance improvements of single-engine business airplanes by the integration of advanced technologies

NASA Technical Reports Server (NTRS)

Kohlman, D. L.

1982-01-01

An assessment is presented of the performance gains and economic impact of the integration in general aviation aircraft of advanced technologies, relating to such aspects of design as propulsion, natural laminar flow, lift augmentation, unconventional configurations, and advanced aluminum and composite structures. All considerations are with reference to a baseline mission of 1300 nm range and 300-knot cruise speed with a 1300-lb payload, and a baseline aircraft with a 40 lb/sq ft wing loading and an aspect ratio of 8. Extensive analytical results are presented from the NASA-sponsored General Aviation Synthesis Program. Attention is given to the relative performance gains to be expected from the single-engined baseline aircraft's use of a low cost general aviation turbine engine, a spark-ignited reciprocating engine, a diesel engine, and a Wankel rotary engine.

On the Problems of Cracking and the Question of Structural Integrity of Engineering Composite Materials

NASA Astrophysics Data System (ADS)

Beaumont, Peter W. R.

2014-02-01

Predicting precisely where a crack will develop in a material under stress and exactly when in time catastrophic fracture of the component will occur is one the oldest unsolved mysteries in the design and building of large engineering structures. Where human life depends upon engineering ingenuity, the burden of testing to prove a "fracture safe design" is immense. For example, when human life depends upon structural integrity as an essential design requirement, it takes ten thousand material test coupons per composite laminate configuration to evaluate an airframe plus loading to ultimate failure tails, wing boxes, and fuselages to achieve a commercial aircraft airworthiness certification. Fitness considerations for long-life implementation of aerospace composites include understanding phenomena such as impact, fatigue, creep, and stress corrosion cracking that affect reliability, life expectancy, and durability of structure. Structural integrity analysis treats the design, the materials used, and figures out how best components and parts can be joined. Furthermore, SI takes into account service duty. However, there are conflicting aims in the complete design process of designing simultaneously for high efficiency and safety assurance throughout an economically viable lifetime with an acceptable level of risk.

Double patterning from design enablement to verification

NASA Astrophysics Data System (ADS)

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

2011-11-01

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

Design of three-dimensional scramjet inlets for hypersonic propulsion

NASA Technical Reports Server (NTRS)

Simmons, J. M.; Weidner, E. H.

1986-01-01

The paper outlines an approach to the design of three-dimensional inlets for scramjet engines. The basis of the techniques used is the method of streamline tracing through an inviscid axisymmetric flow field. A technique is described for making a smooth change of cross-section shape from rectangular to circular. A feature is the considerable use of computer-graphics to provide a 'user-oriented' procedure which can produce promising design configurations for subsequent analysis with CFD codes. An example is given to demonstrate the capabilities of the design techniques.

Process Feasibility Study in Support of Silicon Material, Task 1

NASA Technical Reports Server (NTRS)

Li, K. Y.; Hansen, K. C.; Yaws, C. L.

1979-01-01

During this reporting period, major activies were devoted to process system properties, chemical engineering and economic analyses. Analyses of process system properties was continued for materials involved in the alternate processes under consideration for solar cell grade silicon. The following property data are reported for silicon tetrafluoride: critical constants, vapor pressure, heat of varporization, heat capacity, density, surface tension, viscosity, thermal conductivity, heat of formation and Gibb's free energy of formation. Chemical engineering analysis of the BCL process was continued with primary efforts being devoted to the preliminary process design. Status and progress are reported for base case conditions; process flow diagram; reaction chemistry; material and energy balances; and major process equipment design.

Effect of Tilt of the Propeller Axis on the Longitudinal-stability Characteristics of Single-Engine Airplanes

NASA Technical Reports Server (NTRS)

Goett, Harry J; Delaney, Noel K

1944-01-01

Report presents the results of tests of a model of a single-engine airplane with two different tilts of the propeller axis. The results indicate that on a typical design a 5 degree downward tilt of the propeller axis will considerably reduce the destabilization effects of power. A comparison of the experimental results with those computed by use of existing theory is included. A comparison of the experimental results with those computed by use of existing theory is included. It is shown that the results can be predicted with an accuracy acceptable for preliminary design purposes, particularly at the higher powers where the effects are of significant magnitude.

Biomedical applications of tissue engineering technology: regulatory issues.

PubMed

Hellman, K B

1995-01-01

Novel emerging technologies such as tissue engineering, which utilize the approaches of molecular and cell biology, biotechnology, as well as materials science and engineering, are being used in the development of a wide range of biomedical products developed by industries regulated by the U.S. Food and Drug Administration (FDA). The FDA's mission is to promote and protect the public health by ensuring the safety and effectiveness of pharmaceuticals and medical devices, including those manufactured by novel technology, as assessed by scientific principles and methods. Regulatory review is conducted on a product-by-product basis. To accomplish its mission over the wide range of products in its regulatory purview, the FDA has six centers, each staffed with the scientific and regulatory expertise to evaluate the products in the center's jurisdiction. Recent legislative and regulatory changes are designed to simplify and facilitate the administrative process for evaluating novel combination products emanating from such interdisciplinary technology as tissue engineering and to resolve questions of product regulatory jurisdiction. Under the new procedures, the FDA may designate a lead FDA center for product review based on the primary mode of action of the combination product, with additional center(s) designated to assist in the evaluation in a collaborative or consultative capacity. In addition, FDA centers have increased their cooperation and information sharing with regard to evolving interdisciplinary technology. The FDA InterCenter Tissue Engineering Initiative was established to develop information on intercenter efforts in the evaluation of tissue engineering applications and to identify areas for further consideration. The FDA InterCenter Tissue Engineering Working Group, comprised of staff from the Center for Biologies Evaluation and Research (CBER), Center for Devices and Radiological Health (CDRH), Center for Drug Evaluation and Research (CDER), and Center for Veterinary Medicine (CVM) has developed a Draft Report considering recent developments in tissue engineering and scientific and regulatory issues in the product application areas. The Working Group has identified generic safety and effectiveness issues for consideration by the research and development community in its development of products. The FDA centers are using multiple approaches at their disposal in the evaluation of tissue engineered products including research, data and information monitoring, regulatory guidance, training and education, and cooperation with public and private groups.

Stirling heat pump external heat systems - An appliance perspective

NASA Astrophysics Data System (ADS)

Vasilakis, Andrew D.; Thomas, John F.

A major issue facing the Stirling Engine Heat Pump is system cost, and, in particular, the cost of the External Heat System (EHS). The need for high temperature at the heater head (600 C to 700 C) results in low combustion system efficiencies unless efficient heat recovery is employed. The balance between energy efficiency and use of costly high temperature materials is critical to design and cost optimization. Blower power consumption and NO(x) emissions are also important. A new approach to the design and cost optimization of the EHS was taken by viewing the system from a natural gas-fired appliance perspective. To develop a design acceptable to gas industry requirements, American National Standards Institute (ANSI) code considerations were incorporated into the design process and material selections. A parametric engineering design and cost model was developed to perform the analysis, including the impact of design on NO(x) emissions. Analysis results and recommended EHS design and material choices are given.

Stirling heat pump external heat systems: An appliance perspective

NASA Astrophysics Data System (ADS)

Vasilakis, A. D.; Thomas, J. F.

1992-08-01

A major issue facing the Stirling Engine Heat Pump is system cost, and, in particular, the cost of the External Heat System (EHS). The need for high temperature at the heater head (600 C to 700 C) results in low combustion system efficiencies unless efficient heat recovery is employed. The balance between energy efficiency and use of costly high temperature materials is critical to design and cost optimization. Blower power consumption and NO(x) emissions are also important. A new approach to the design and cost optimization of the EHS system was taken by viewing the system from a natural gas-fired appliance perspective. To develop a design acceptable to gas industry requirements, American National Standards Institute (ANSI) code considerations were incorporated into the design process and material selections. A parametric engineering design and cost model was developed to perform the analysis, including the impact of design on NO(x) emissions. Analysis results and recommended EHS design and material choices are given.

Status of advanced orbital transfer propulsion

NASA Technical Reports Server (NTRS)

Cooper, L. P.

1985-01-01

A new Orbital Transfer Vehicle (OTV) propulsion system that will be used in conjunction with the Space Shuttle, Space Station and Orbit Maneuvering Vehicle is discussed. The OTV will transfer men, large space structures and conventional payloads between low Earth and higher energy orbits. Space probes carried by the OTV will continue the exploration of the solar system. When lunar bases are established, the OTV will be their transportation link to Earth. Critical engine design considerations based upon the need for low cost payload delivery, space basing, reusability, aeroassist maneuvering, low g transfers of large space structures and man rating are described. The importance of each of these to propulsion design is addressed. Specific propulsion requirements discussed are: (1) high performance H2/O2 engine; (2) multiple engine configurations totalling no more than 15,000 lbf thrust 15 to 20 hr life; (3) space maintainable modular design; (4) health monitoring capability; and (5) safety and mission success with backup auxiliary propulsion.

Design considerations for a Space Shuttle Main Engine turbine blade made of single crystal material

NASA Technical Reports Server (NTRS)

Abdul-Aziz, A.; August, R.; Nagpal, V.

1993-01-01

Nonlinear finite-element structural analyses were performed on the first stage high-pressure fuel turbopump blade of the Space Shuttle Main Engine. The analyses examined the structural response and the dynamic characteristics at typical operating conditions. Single crystal material PWA-1480 was considered for the analyses. Structural response and the blade natural frequencies with respect to the crystal orientation were investigated. The analyses were conducted based on typical test stand engine cycle. Influence of combined thermal, aerodynamic, and centrifugal loadings was considered. Results obtained showed that the single crystal secondary orientation effects on the maximum principal stresses are not highly significant.

Seismic hazard assessment: Issues and alternatives

USGS Publications Warehouse

Wang, Z.

2011-01-01

Seismic hazard and risk are two very important concepts in engineering design and other policy considerations. Although seismic hazard and risk have often been used inter-changeably, they are fundamentally different. Furthermore, seismic risk is more important in engineering design and other policy considerations. Seismic hazard assessment is an effort by earth scientists to quantify seismic hazard and its associated uncertainty in time and space and to provide seismic hazard estimates for seismic risk assessment and other applications. Although seismic hazard assessment is more a scientific issue, it deserves special attention because of its significant implication to society. Two approaches, probabilistic seismic hazard analysis (PSHA) and deterministic seismic hazard analysis (DSHA), are commonly used for seismic hazard assessment. Although PSHA has been pro-claimed as the best approach for seismic hazard assessment, it is scientifically flawed (i.e., the physics and mathematics that PSHA is based on are not valid). Use of PSHA could lead to either unsafe or overly conservative engineering design or public policy, each of which has dire consequences to society. On the other hand, DSHA is a viable approach for seismic hazard assessment even though it has been labeled as unreliable. The biggest drawback of DSHA is that the temporal characteristics (i.e., earthquake frequency of occurrence and the associated uncertainty) are often neglected. An alternative, seismic hazard analysis (SHA), utilizes earthquake science and statistics directly and provides a seismic hazard estimate that can be readily used for seismic risk assessment and other applications. ?? 2010 Springer Basel AG.

Optimized bio-inspired stiffening design for an engine nacelle.

PubMed

Lazo, Neil; Vodenitcharova, Tania; Hoffman, Mark

2015-11-04

Structural efficiency is a common engineering goal in which an ideal solution provides a structure with optimized performance at minimized weight, with consideration of material mechanical properties, structural geometry, and manufacturability. This study aims to address this goal in developing high performance lightweight, stiff mechanical components by creating an optimized design from a biologically-inspired template. The approach is implemented on the optimization of rib stiffeners along an aircraft engine nacelle. The helical and angled arrangements of cellulose fibres in plants were chosen as the bio-inspired template. Optimization of total displacement and weight was carried out using a genetic algorithm (GA) coupled with finite element analysis. Iterations showed a gradual convergence in normalized fitness. Displacement was given higher emphasis in optimization, thus the GA optimization tended towards individual designs with weights near the mass constraint. Dominant features of the resulting designs were helical ribs with rectangular cross-sections having large height-to-width ratio. Displacement reduction was at 73% as compared to an unreinforced nacelle, and is attributed to the geometric features and layout of the stiffeners, while mass is maintained within the constraint.

Space shuttle main engine: Interactive design challenges

NASA Technical Reports Server (NTRS)

Mccarty, J. P.; Wood, B. K.

1985-01-01

The operating requirements established by NASA for the SSME were considerably more demanding than those for earlier rocket engines used in the military launch vehicles or Apollo program. The SSME, in order to achieve the high performance, low weight, long life, reusable objectives, embodied technical demands far in excess of its predecessor rocket engines. The requirements dictated the use of high combustion pressure and the staged combustion cycle which maximizes performance through total use of all propellants in the main combustion process. This approach presented a myriad of technical challenges for maximization of performance within attainable state of the art capabilities for operating pressures, operating temperatures and rotating machinery efficiencies. Controlling uniformity of the high pressure turbomachinery turbine temperature environment was a key challenge for thrust level and life capability demanding innovative engineering. New approaches in the design of the components were necessary to accommodate the multiple use, minimum maintenance objectives. Included were the use of line replaceable units to facilitate field maintenance automatic checkout and internal inspection capabilities.

Apollo experience report: Guidance and control systems. Engineering simulation program

NASA Technical Reports Server (NTRS)

Gilbert, D. W.

1973-01-01

The Apollo Program experience from early 1962 to July 1969 with respect to the engineering-simulation support and the problems encountered is summarized in this report. Engineering simulation in support of the Apollo guidance and control system is discussed in terms of design analysis and verification, certification of hardware in closed-loop operation, verification of hardware/software compatibility, and verification of both software and procedures for each mission. The magnitude, time, and cost of the engineering simulations are described with respect to hardware availability, NASA and contractor facilities (for verification of the command module, the lunar module, and the primary guidance, navigation, and control system), and scheduling and planning considerations. Recommendations are made regarding implementation of similar, large-scale simulations for future programs.

The Development of Environmental Barrier Coatings for SiCSiC Ceramic Matrix Composites: Challenges and Opportunities

NASA Technical Reports Server (NTRS)

Zhu, Dongming

2014-01-01

Environmental barrier coatings (EBCs) and SiC/SiC ceramic matrix composites (CMCs) systems will play a crucial role in future turbine engines for hot-section component applications because of their ability to significantly increase engine operating temperatures, reduce engine weight and cooling requirements. The development of prime-reliant environmental barrier coatings is a key to enable the applications of the envisioned CMC components to help achieve next generation engine performance and durability goals. This paper will primarily address the performance requirements and design considerations of environmental barrier coatings for turbine engine applications. The emphasis is placed on current candidate environmental barrier coating systems for SiCSiC CMCs, their performance benefits and design limitations in long-term operation and combustion environments. Major technical barriers in developing advanced environmental barrier coating systems, the coating integrations with next generation CMC turbine components having improved environmental stability, cyclic durability and system performance will be described. The development trends for turbine environmental barrier coating systems by utilizing improved compositions, state-of-the-art processing methods, and simulated environment testing and durability modeling will be discussed.

How to design and fly your humanly space object in space?

NASA Astrophysics Data System (ADS)

Balint, Tibor; Hall, Ashley

2016-06-01

Today's space exploration, both robotic- and human-exploration driven, is dominated by objects and artifacts which are mostly conceived, designed and built through technology and engineering approaches. They are functional, reliable, safe, and expensive. Building on considerations and concepts established in an earlier paper, we can state that the current approach leaves very little room for art and design based objects, as organizations-typically led by engineers, project and business managers-see the inclusion of these disciplines and artifacts as nice to have instead of a genuine need, let alone requirement. In this paper we will offer initial discussions about where design and engineering practices are different or similar and how to bridge them and highlight the benefits that domains such as design or art can offer to space exploration. Some of the design considerations and approaches will be demonstrated through the double diamond of divergence-convergence cycles of design, leading to an experimental piece called a ;cybernetic astronaut chair;, which was designed as a form of abstraction and discussion point to highlight a subset of concepts and ideas that designers may consider when designing objects for space use, with attention to human-centered or humanly interactions. Although there are few suggested functional needs for chairs in space, they can provide reassuring emotional experiences from home, while being far away from home. In zero gravity, back-to-back seats provide affordances-or add variety in a cybernetic sense-to accommodate two astronauts simultaneously, while implying the circularity of cybernetics in a rather symbolic way. The cybernetic astronaut chair allows us to refine the three-actor model proposed in a previous paper, defining the circular interactions between the artist or designer; object or process; and user or observer. We will also dedicate a brief discussion to the process of navigating through the complex regulations of space agencies, from solicitations through development and testing, to space flight. The provided insights to designers and artists, related to agency-driven processes and requirements, may help to deconvolute the steps and may lead to flying their objects or artifacts in space.

System-Level Design of a Shape Memory Alloy Actuator for Active Clearance Control in the High-Pressure Turbine

NASA Technical Reports Server (NTRS)

DeCastro, Jonathan A.; Melcher, Kevin J.; Noebe, Ronald D.

2005-01-01

This paper describes results of a numerical analysis evaluating the feasibility of high-temperature shape memory alloys (HTSMA) for active clearance control actuation in the high-pressure turbine section of a modern turbofan engine. The prototype actuator concept considered here consists of parallel HTSMA wires attached to the shroud that is located on the exterior of the turbine case. A transient model of an HTSMA actuator was used to evaluate active clearance control at various operating points in a test bed aircraft engine simulation. For the engine under consideration, each actuator must be designed to counteract loads from 380 to 2000 lbf and displace at least 0.033 inches. Design results show that an actuator comprised of 10 wires 2 inches in length is adequate for control at critical engine operating points and still exhibits acceptable failsafe operability and cycle life. A proportional-integral-derivative (PID) controller with integrator windup protection was implemented to control clearance amidst engine transients during a normal mission. Simulation results show that the control system exhibits minimal variability in clearance control performance across the operating envelope. The final actuator design is sufficiently small to fit within the limited space outside the high-pressure turbine case and is shown to consume only small amounts of bleed air to adequately regulate temperature.

Knowledge, attitude and practices for design for safety: A study on civil & structural engineers.

PubMed

Goh, Yang Miang; Chua, Sijie

2016-08-01

Design for safety (DfS) (also known as prevention through design, safe design and Construction (Design and Management)) promotes early consideration of safety and health hazards during the design phase of a construction project. With early intervention, hazards can be more effectively eliminated or controlled leading to safer worksites and construction processes. DfS is practiced in many countries, including Australia, the UK, and Singapore. In Singapore, the Manpower Ministry enacted the DfS Regulations in July 2015, which will be enforced from August 2016 onwards. Due to the critical role of civil and structural (C&S) engineers during design and construction, the DfS knowledge, attitude and practices (KAP) of C&S engineers have significant impact on the successful implementation of DfS. Thus, this study aims to explore the DfS KAP of C&S engineers so as to guide further research in measuring and improving DfS KAP of designers. During the study, it was found that there is a lack of KAP studies in construction management. Therefore, this study also aims to provide useful lessons for future applications of the KAP framework in construction management research. A questionnaire was developed to assess the DfS KAP of C&S engineers. The responses provided by 43 C&S engineers were analyzed. In addition, interviews with experienced construction professionals were carried out to further understand perceptions of DfS and related issues. The results suggest that C&S engineers are supportive of DfS, but the level of DfS knowledge and practices need to be improved. More DfS guidelines and training should be made available to the engineers. To ensure that DfS can be implemented successfully, there is a need to study the contractual arrangements between clients and designers and the effectiveness of different implementation approaches for the DfS process. The questionnaire and findings in this study provided the foundation for a baseline survey with larger sample size, which is currently being planned. In contrast to earlier studies, the study showed that the responding C&S engineers were supportive of the DfS. The study showed that the key to improving the DfS KAP of C&S engineers is by improving clients' motivation for DfS. Copyright © 2015 Elsevier Ltd. All rights reserved.

Optimization of suitable ethanol blend ratio for motorcycle engine using response surface method.

PubMed

Chen, Yu-Liang; Chen, Suming; Tsai, Jin-Ming; Tsai, Chao-Yin; Fang, Hsin-Hsiung; Yang, I-Chang; Liu, Sen-Yuan

2012-01-01

In view of energy shortage and air pollution, ethanol-gasoline blended fuel used for motorcycle engine was studied in this work. The emissions of carbon monoxide (CO), nitrogen oxides (NO(X)) and engine performance of a 125 cc four-stroke motorcycle engine with original carburetor using ethanol-gasoline fuels were investigated. The model of three-variable Box Behnken design (BBD) was used for experimental design, the ethanol blend ratios were prepared at 0, 10, 20 vol%; the speeds of motorcycle were selected as 30, 45, 60 km/h; and the throttle positions were set at 30, 60, 90 %. Both engine performance and air pollutant emissions were then analyzed by response surface method (RSM) to yield optimum operation parameters for tolerable pollutant emissions and maximum engine performance. The RSM optimization analysis indicated that the most suitable ethanol-gasoline blended ratio was found at the range of 3.92-4.12 vol% to yield a comparable fuel conversion efficiency, while considerable reductions of exhaust pollutant emissions of CO (-29 %) and NO(X) (-12 %) when compared to pure gasoline fuel. This study demonstrated low ethanol-gasoline blended fuels could be used in motorcycle carburetor engines without any modification to keep engine power while reducing exhaust pollutants.

Turbojet-engine Starting and Acceleration

NASA Technical Reports Server (NTRS)

Mc Cafferty, R. J.; Straight, D. M.

1956-01-01

From considerations of safety and reliability in performance of gas-turbine aircraft, it is clear that engine starting and acceleration are of utmost importance. For this reason extensive efforts have been devoted to the investigation of the factors involved in the starting and acceleration of engines. In chapter III it is shown that certain basic combustion requirements must be met before ignition can occur; consequently, the design and operation of an engine must be tailored to provide these basic requirements in the combustion zone of the engine, particularly in the vicinity of the ignition source. It is pointed out in chapter III that ignition by electrical discharges is aided by high pressure, high temperature, low gas velocity and turbulence, gaseous fuel-air mixture, proper mixture strength, and-an optimum spark. duration. The simultaneous achievement of all these requirements in an actual turbojet-engine combustor is obviously impossible, yet any attempt to satisfy as many requirements as possible will result in lower ignition energies, lower-weight ignition systems, and greater reliability. These factors together with size and cost considerations determine the acceptability of the final ignition system. It is further shown in chapter III that the problem of wall quenching affects engine starting. For example, the dimensions of the volume to be burned must be larger than the quenching distance at the lowest pressure and the most adverse fuel-air ratio encountered. This fact affects the design of cross-fire tubes between adjacent combustion chambers in a tubular-combustor turbojet engine. Only two chambers in these engines contain spark plugs; therefore, the flame must propagate through small connecting tubes between the chambers. The quenching studies indicate that if the cross-fire tubes are too narrow the flame will not propagate from one chamber to another. In order to better understand the role of the basic factors in actual engine operation, many investigations have been conducted in single combustors from gas-turbine engines and in full-scale engines in altitude tanks and in flight. The purpose of the present chapter is to discuss the results of such studies and, where possible, to interpret these results qualitatively in terms of the basic requirements reported in chapter III. The discussion parallels the three phases of turbojet engine starting: (1) Ignition of the fuel-air mixture (2) Propagation of flame throughout the combustion zone (3) Acceleration of the engine to operating speed.

Zonation and assessment of frozen-ground conditions along the China-Russia Crude Oil Pipeline route from Mo’he to Daqing, Northeastern China

NASA Astrophysics Data System (ADS)

Jin, H.; Hao, J.; Chang, X.

2009-12-01

The proposed China-Russia Crude Oil Pipeline (CRCOP), 813 mm in diameter, is designed to transport 603,000 barrels of Siberian crude oil per day using conventional burial across 1,030 km of frozen-ground. About 500 boreholes, with depths of 5 to 20 m, were drilled and cored for analyses, and the frozen-ground conditions were evaluated. After detailed surveys and analyses of the permafrost conditions along the pipeline route, a conventional burial construction mode at a nominal depth of 1.5 m was adopted. This paper discusses the principles and criteria for the zonation and assessment of the frozen-ground environments and conditions of engineering geology for the design, construction, operation of the pipeline system based on an extensive and in-depth summary and analysis of the survey and exploration data. Full consideration of the characteristics of pipelining crude oil at ambient temperatures in the permafrost regions and the interactive processes between the pipeline and foundation soils were taken into account. Two zones of frozen-ground environment and conditions of engineering geology, i. e. seasonally-frozen-ground and permafrost, were defined on the basis of the regional distribution and differentiations in frozen-ground environments and conditions. Then, four subzones of the permafrost zone were classified according to the areal extent, taking into consideration the temperatures and thicknesses of permafrost, as well as changes in vegetation coverage. In the four subzones, 151 sections of engineering geology were categorized according to the ice/moisture contents of the permafrost, as well as the classes of frost-heaving and thaw-settlement potentials. These 151 sections are comprehensively summarized into four types for engineering construction and operation: good, fair, poor, and very poor, for overall conditions of engineering geology. The zonation, assessment principles and criteria have been applied in the design of the pipeline. They have also been used as the scientific bases for the construction, environmental management, operation and maintenance/contingency plans

ENGINEERING AND CONSTRUCTING THE HALLAM NUCLEAR POWER FACILITY REACTOR STRUCTURE

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

Mahlmeister, J E; Haberer, W V; Casey, D F

1960-12-15

The Hallam Nuclear Power Facility reactor structure, including the cavity liner, is described, and the design philosophy and special design requirements which were developed during the preliminary and final engineering phases of the project are explained. The structure was designed for 600 deg F inlet and 1000 deg F outlet operating sodium temperatures and fabricated of austenitic and ferritic stainless steels. Support for the reactor core components and adequate containment for biological safeguards were readily provided even though quite conservative design philosophy was used. The calculated operating characteristics, including heat generation, temperature distributions and stress levels for full-power operation, aremore » summarized. Ship fabrication and field installation experiences are also briefly related. Results of this project have established that the sodium graphite reactor permits practical and economical fabrication and field erection procedures; considerably higher operating design temperatures are believed possible without radical design changes. Also, larger reactor structures can be similarly constructed for higher capacity (300 to 1000 Mwe) nuclear power plants. (auth)« less

Portable Life Support System: PLSS 101

NASA Technical Reports Server (NTRS)

Thomas, Gretchen A.

2011-01-01

This presentation reviewed basic interfaces and considerations necessary for prototype suit hardware integration from an advanced spacesuit engineer perspective during the early design and test phases. The discussion included such topics such as the human interface, suit pass-throughs, keep-out zones, hardware form factors, subjective feedback from suit tests, and electricity in the suit.

Yamato: Bringing the Moon to the Earth ... Again

NASA Technical Reports Server (NTRS)

Lam, King; Martinelli, Scott; Patel, Neal; Powell, David; Smith, Brandon

2008-01-01

The Yamato mission to the lunar South Pole-Aitken Basin returns samples that enable dating of lunar formation and the lunar bombardment period. The design of the Yamato mission is based on a systems engineering process which takes an advanced consideration of cost and mission risk to give the mission a high probability of success.

Dynamic balance improvement program

NASA Technical Reports Server (NTRS)

Butner, M. F.

1983-01-01

The reduction of residual unbalance in the space shuttle main engine (SSME) high pressure turbopump rotors was addressed. Elastic rotor response to unbalance and balancing requirements, multiplane and in housing balancing, and balance related rotor design considerations were assessed. Recommendations are made for near term improvement of the SSME balancing and for future study and development efforts.

The Potential Impact of Mars' Atmospheric Dust on Future Human Exploration of the Red Planet: Mars Sample Return Considerations

NASA Astrophysics Data System (ADS)

Winterhalter, D.; Levine, J. S.; Kerschmann, R.; Beaty, D. W.; Carrier, B. L.; Ashley, J. W.

2018-04-01

To aid early engineering and mission design efforts, the NESC held a workshop on the atmospheric dust and its impact on the human exploration of Mars. Of great interest is the possible Mars Sample Return contribution that will help to answer pertinent questions.

Second Insulin Pump Safety Meeting: Summary Report

PubMed Central

Zhang, Yi; Jones, Paul L.; Klonoff, David C.

2010-01-01

Diabetes Technology Society facilitated a second meeting of insulin pump experts at Mills-Peninsula Health Services, San Mateo, California on November 4, 2009, at the request of the Food and Drug Administration, Center for Devices and Radiological Health, Office of Science and Engineering Laboratories. The first such meeting was held in Bethesda, Maryland, on November 12, 2008. The group of physicians, nurses, diabetes educators, and engineers from across the United States discussed safety issues in insulin pump therapy and recommended adjustments to current insulin pump design and use to enhance overall safety. The meeting discussed safety issues in the context of pump operation; software; hardware; physical structure; electrical, biological, and chemical considerations; use; and environment from engineering, medical, nursing, and pump/user perspectives. There was consensus among meeting participants that insulin pump designs have made great progress in improving the quality of life of people with diabetes, but much more remains to be done. PMID:20307411

Pore size engineering applied to the design of separators for nickel-hydrogen cells and batteries

NASA Technical Reports Server (NTRS)

Abbey, K. M.; Britton, D. L.

1983-01-01

Pore size engineering in starved alkaline multiplate cells involves adopting techniques to widen the volume tolerance of individual cells. Separators with appropriate pore size distributions and wettability characteristics (capillary pressure considerations) to have wider volume tolerances and an ability to resist dimensional changes in the electrodes were designed. The separators studied for potential use in nickel-hydrogen cells consist of polymeric membranes as well as inorganic microporous mats. In addition to standard measurements, the resistance and distribution of electrolyte as a function of total cell electrolyte content were determined. New composite separators consisting of fibers, particles and/or binders deposited on Zircar cloth were developed in order to engineer the proper capillary pressure characteristics in the separator. These asymmetric separators were prepared from a variety of fibers, particles and binders. Previously announced in STAR as N83-24571

A kinetic modeling of chondrocyte culture for manufacture of tissue-engineered cartilage.

PubMed

Kino-Oka, Masahiro; Maeda, Yoshikatsu; Yamamoto, Takeyuki; Sugawara, Katsura; Taya, Masahito

2005-03-01

For repairing articular cartilage defects, innovative techniques based on tissue engineering have been developed and are now entering into the practical stage of clinical application by means of grafting in vitro cultured products. A variety of natural and artificial materials available for scaffolds, which permit chondrocyte cells to aggregate, have been designed for their ability to promote cell growth and differentiation. From the viewpoint of the manufacturing process for tissue-engineered cartilage, the diverse nature of raw materials (seeding cells) and end products (cultured cartilage) oblige us to design a tailor-made process with less reproducibility, which is an obstacle to establishing a production doctrine based on bioengineering knowledge concerning growth kinetics and modeling as well as designs of bioreactors and culture operations for certification of high product quality. In this article, we review the recent advances in the manufacturing of tissue-engineered cartilage. After outlining the manufacturing processes for tissue-engineered cartilage in the first section, the second and third sections, respectively, describe the three-dimensional culture of chondrocytes with Aterocollagen gel and kinetic model consideration as a tool for evaluating this culture process. In the final section, culture strategy is discussed in terms of the combined processes of monolayer growth (ex vivo chondrocyte cell expansion) and three-dimensional growth (construction of cultured cartilage in the gel).

Progress on Shape Memory Alloy Actuator Development for Active Clearance Control

NASA Technical Reports Server (NTRS)

DeCastro, Jonathan; Melcher, Kevin; Noebe, Ronald

2006-01-01

Results of a numerical analysis evaluating the feasibility of high-temperature shape memory alloys (HTSMA) for active clearance control actuation in the high-pressure turbine section of a modern turbofan engine has been conducted. The prototype actuator concept considered here consists of parallel HTSMA wires attached to the shroud that is located on the exterior of the turbine case. A transient model of an HTSMA actuator was used to evaluate active clearance control at various operating points in a test bed aircraft engine simulation. For the engine under consideration, each actuator must be designed to counteract loads from 380 to 2000 lbf and displace at least 0.033 in. Design results show that an actuator comprised of 10 wires 2 in. in length is adequate for control at critical engine operating points and still exhibit acceptable failsafe operability and cycle life. A proportional-integral-derivative (PID) controller with integrator windup protection was implemented to control clearance amidst engine transients during a normal mission. Simulation results show that the control system exhibits minimal variability in clearance control performance across the operating envelope. The final actuator design is sufficiently small to fit within the limited space outside the high-pressure turbine case and is shown to consume only small amounts of bleed air to adequately regulate temperature.

The Evolution of Inquiry Activities in the Akamai Observatory Short Course, 2004-2009

NASA Astrophysics Data System (ADS)

Rice, E. L.; McElwain, M.; Sonnett, S.; Rafelski, M.

2010-12-01

The Akamai Observatory Short Course (AOSC) is a five-day course of activities designed to prepare college students majoring in science, technology, engineering, and mathematics (STEM) fields for internships at observatories on the Big Island of Hawai'i. The design and implementation of inquiry-based activities in the AOSC have evolved considerably over the six years of the course. The content goals have always focused on the basic understanding of light and optics necessary to understand telescopes, but the scientific process goals gradually evolved to reflect the increasingly recognized importance of engineering design skills for successful observatory internships. In 2004 the inquiry-based activities were limited to one well-established Color, Light, and Spectra activity. In subsequent years more activities were customized and expanded upon to reflect the learners' diverse academic backgrounds, the developing goals of the short course, and feedback from internship hosts. The most recent inquiry, the Design and Build a Telescope activity, engaged students in designing and building a simple telescope, emphasizing science and engineering process skills in addition to science content. This activity was influenced by the Mission Design activity, added in 2006, that incorporated the application of inquiry-based learning to the engineering design process and allowed students to draw upon their diverse prior knowledge and experience. In this paper we describe the inquiry-based activities in the AOSC in the context of its year-to-year evolution, including the conceptual and pragmatic changes to the short course that influenced the evolution.

U.S. Seismic Design Maps Web Application

NASA Astrophysics Data System (ADS)

Martinez, E.; Fee, J.

2015-12-01

The application computes earthquake ground motion design parameters compatible with the International Building Code and other seismic design provisions. It is the primary method for design engineers to obtain ground motion parameters for multiple building codes across the country. When designing new buildings and other structures, engineers around the country use the application. Users specify the design code of interest, location, and other parameters to obtain necessary ground motion information consisting of a high-level executive summary as well as detailed information including maps, data, and graphs. Results are formatted such that they can be directly included in a final engineering report. In addition to single-site analysis, the application supports a batch mode for simultaneous consideration of multiple locations. Finally, an application programming interface (API) is available which allows other application developers to integrate this application's results into larger applications for additional processing. Development on the application has proceeded in an iterative manner working with engineers through email, meetings, and workshops. Each iteration provided new features, improved performance, and usability enhancements. This development approach positioned the application to be integral to the structural design process and is now used to produce over 1800 reports daily. Recent efforts have enhanced the application to be a data-driven, mobile-first, responsive web application. Development is ongoing, and source code has recently been published into the open-source community on GitHub. Open-sourcing the code facilitates improved incorporation of user feedback to add new features ensuring the application's continued success.

The First Development of Human Factors Engineering Requirements for Application to Ground Task Design for a NASA Flight Program

NASA Technical Reports Server (NTRS)

Dischinger, H. Charles, Jr.; Stambolian, Damon B.; Miller, Darcy H.

2008-01-01

The National Aeronautics and Space Administration has long applied standards-derived human engineering requirements to the development of hardware and software for use by astronauts while in flight. The most important source of these requirements has been NASA-STD-3000. While there have been several ground systems human engineering requirements documents, none has been applicable to the flight system as handled at NASA's launch facility at Kennedy Space Center. At the time of the development of previous human launch systems, there were other considerations that were deemed more important than developing worksites for ground crews; e.g., hardware development schedule and vehicle performance. However, experience with these systems has shown that failure to design for ground tasks has resulted in launch schedule delays, ground operations that are more costly than they might be, and threats to flight safety. As the Agency begins the development of new systems to return humans to the moon, the new Constellation Program is addressing this issue with a new set of human engineering requirements. Among these requirements is a subset that will apply to the design of the flight components and that is intended to assure ground crew success in vehicle assembly and maintenance tasks. These requirements address worksite design for usability and for ground crew safety.

The mismeasure of machine: Synthetic biology and the trouble with engineering metaphors.

PubMed

Boudry, Maarten; Pigliucci, Massimo

2013-12-01

The scientific study of living organisms is permeated by machine and design metaphors. Genes are thought of as the "blueprint" of an organism, organisms are "reverse engineered" to discover their functionality, and living cells are compared to biochemical factories, complete with assembly lines, transport systems, messenger circuits, etc. Although the notion of design is indispensable to think about adaptations, and engineering analogies have considerable heuristic value (e.g., optimality assumptions), we argue they are limited in several important respects. In particular, the analogy with human-made machines falters when we move down to the level of molecular biology and genetics. Living organisms are far more messy and less transparent than human-made machines. Notoriously, evolution is an opportunistic tinkerer, blindly stumbling on "designs" that no sensible engineer would come up with. Despite impressive technological innovation, the prospect of artificially designing new life forms from scratch has proven more difficult than the superficial analogy with "programming" the right "software" would suggest. The idea of applying straightforward engineering approaches to living systems and their genomes-isolating functional components, designing new parts from scratch, recombining and assembling them into novel life forms-pushes the analogy with human artifacts beyond its limits. In the absence of a one-to-one correspondence between genotype and phenotype, there is no straightforward way to implement novel biological functions and design new life forms. Both the developmental complexity of gene expression and the multifarious interactions of genes and environments are serious obstacles for "engineering" a particular phenotype. The problem of reverse-engineering a desired phenotype to its genetic "instructions" is probably intractable for any but the most simple phenotypes. Recent developments in the field of bio-engineering and synthetic biology reflect these limitations. Instead of genetically engineering a desired trait from scratch, as the machine/engineering metaphor promises, researchers are making greater strides by co-opting natural selection to "search" for a suitable genotype, or by borrowing and recombining genetic material from extant life forms. Copyright © 2013 Elsevier Ltd. All rights reserved.

Patterns of informal reasoning in the context of socioscientific decision making

NASA Astrophysics Data System (ADS)

Sadler, Troy D.; Zeidler, Dana L.

2005-01-01

The purpose of this study is to contribute to a theoretical knowledge base through research by examining factors salient to science education reform and practice in the context of socioscientific issues. The study explores how individuals negotiate and resolve genetic engineering dilemmas. A qualitative approach was used to examine patterns of informal reasoning and the role of morality in these processes. Thirty college students participated individually in two semistructured interviews designed to explore their informal reasoning in response to six genetic engineering scenarios. Students demonstrated evidence of rationalistic, emotive, and intuitive forms of informal reasoning. Rationalistic informal reasoning described reason-based considerations; emotive informal reasoning described care-based considerations; and intuitive reasoning described considerations based on immediate reactions to the context of a scenario. Participants frequently relied on combinations of these reasoning patterns as they worked to resolve individual socioscientific scenarios. Most of the participants appreciated at least some of the moral implications of their decisions, and these considerations were typically interwoven within an overall pattern of informal reasoning. These results highlight the need to ensure that science classrooms are environments in which intuition and emotion in addition to reason are valued. Implications and recommendations for future research are discussed.

ALARA development in Mexico

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

Lopez, M.A.M.

1995-03-01

Even though the ALARA philosophy was formally implemented in the early 1980`s, to some extent, ALARA considerations already had been incorporated into the design of most commercial equipment and facilities based on experience and engineering development. In Mexico, the design of medical and industrial facilities were based on international recommendations containing those considerations. With the construction of Laguna Verde Nuclear Power Station, formal ALARA groups were created to review some parts of its design, and to prepare the ALARA Program and related procedures necessary for its commercial operation. This paper begins with a brief historical description of ALARA development inmore » Mexico, and then goes on to discuss our regulatory frame in Radiation Protection, some aspects of the ALARA Program, efforts in controlling and reducing of sources of radiation, and finally, future perspectives in the ALARA field.« less

FEL (free-electron lasers) undulator technology and synchrotron radiation source requirements

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

Robinson, K.; Quimby, D.; Slater, J.

This paper describes design and construction considerations of the THUNDER undulator, for use in free-electron laser experiments at visible wavelengths. For the parameters of these experiments, an unusually high degree of optimization of the electron-photon interaction is required and, as a result, THUNDER is built to especially high mechanical and magnetic precision. Except for its narrow magnet gap, the 5-meter THUNDER undulator is quite similar to insertion devices under consideration for the proposed 6-GeV storage ring. The engineering and physics approach adopted for this FEL modulator design is directly applicable to insertion device development. The tolerance limits to THUNDER, establishedmore » by modeling and design and achieved through careful control of mechanical and magnetic errors, are essential to the next generation of insertion devices.« less

NASA/DOD Aerospace Knowledge Diffusion Research Project. Paper 45: A comparison of the information-seeking behaviors of three groups of US aerospace engineers

NASA Technical Reports Server (NTRS)

Kennedy, John M.; Pinelli, Thomas E.; Barclay, Rebecca O.

1995-01-01

To understand the transfer of scientific and technical information (STI) in aerospace, it is necessary to understand the characteristics and behaviors of those who create and use STI. In this paper, we analyze the similarities and differences in the scientific and technical information-seeking behaviors of three groups of US aerospace engineers and scientists. We describe some of their demographic characteristics and their duties and responsibilities as a method of understanding their STI use patterns. There is considerable diversity among aerospace engineers in their use of STI. In general, engineers engaged in research use more STI than those who are in design/development and manufacturing/production. Research engineers also use different standards to determine the STI sources and products that they will use.

Bonded foil pressure transducers

NASA Astrophysics Data System (ADS)

Daube, Bernie W.

The design of bonded-foil pressure transducers is discussed, with consideration given to individual components of both the electrical and the mechanical sections of the bonded-foil pressure transducers, as well as to the temperature control and the accuracy specification of these devices. Particular attention is given to applications of bonded foil pressure transducers, which include solid and liquid rocket engine testing for fuel and exhaust pressures, fuel and oil pressure monitoring on jet engines, and nuclear underground safety system pressure monitoring and nuclear test monitoring. A diagram of a transducer cutaway view is included.

Investigation of Noise Field and Velocity Profiles of an Afterburning Engine

NASA Technical Reports Server (NTRS)

North, Warren J.; Callaghan, E. E.; Lanzo, C. D.

1954-01-01

Sound pressure levels, frequency spectrum, and jet velocity profiles are presented for an engine-afterburner combination at various values of afterburner fuel - air ratio. At the high fuel-air ratios, severe low-frequency resonance was encountered which represented more than half the total energy in the sound spectrum. At similar thrust conditions, lower sound pressure levels were obtained from a current fighter air craft with a different afterburner configuration. The lower sound pressure levels are attributed to resonance-free afterburner operation and thereby indicate the importance of acoustic considerations in afterburner design.

Reliability evaluation methodology for NASA applications

NASA Technical Reports Server (NTRS)

Taneja, Vidya S.

1992-01-01

Liquid rocket engine technology has been characterized by the development of complex systems containing large number of subsystems, components, and parts. The trend to even larger and more complex system is continuing. The liquid rocket engineers have been focusing mainly on performance driven designs to increase payload delivery of a launch vehicle for a given mission. In otherwords, although the failure of a single inexpensive part or component may cause the failure of the system, reliability in general has not been considered as one of the system parameters like cost or performance. Up till now, quantification of reliability has not been a consideration during system design and development in the liquid rocket industry. Engineers and managers have long been aware of the fact that the reliability of the system increases during development, but no serious attempts have been made to quantify reliability. As a result, a method to quantify reliability during design and development is needed. This includes application of probabilistic models which utilize both engineering analysis and test data. Classical methods require the use of operating data for reliability demonstration. In contrast, the method described in this paper is based on similarity, analysis, and testing combined with Bayesian statistical analysis.

MDO and Cross-Disciplinary Practice in R&D: A Portrait of Principles and Current Practice

NASA Technical Reports Server (NTRS)

Rivas McGowan, Anna-Maria; Papalambros, Panos Y.; Baker, Wayne E.

2014-01-01

For several decades, Multidisciplinary Design Optimization (MDO) has served an important role in aerospace engineering by incorporating physics based disciplinary models into integrated system or sub-system models for use in research, development, (R&D) and design. This paper examines MDO's role in facilitating the integration of the researchers from different single disciplines during R&D and early design of large-scale complex engineered systems (LaCES) such as aerospace systems. The findings in this paper are summarized from a larger study on interdisciplinary practices and perspectives that included considerable empirical data from surveys, interviews, and ethnography. The synthesized findings were derived by integrating the data with theories from organization science and engineering. The over-arching finding is that issues related to cognition, organization, and social interrelations mostly dominate interactions across disciplines. Engineering issues, such as the integration of hardware or physics-based models, are not as significant. Correspondingly, the data showed that MDO is not the primary integrator of researchers working across disciplines during R&D and early design of LaCES. Cognitive focus such as analysis versus design, organizational challenges such as incentives, and social opportunities such as personal networks often drove the human interactive practices among researchers from different disciplines. Facilitation of the inherent confusion, argument, and learning in crossdisciplinary research was identified as one of several needed elements of enabling successful research across disciplines.

Additive Manufacturing Design Considerations for Liquid Engine Components

NASA Technical Reports Server (NTRS)

Whitten, Dave; Hissam, Andy; Baker, Kevin; Rice, Darron

2014-01-01

The Marshall Space Flight Center's Propulsion Systems Department has gained significant experience in the last year designing, building, and testing liquid engine components using additive manufacturing. The department has developed valve, duct, turbo-machinery, and combustion device components using this technology. Many valuable lessons were learned during this process. These lessons will be the focus of this presentation. We will present criteria for selecting part candidates for additive manufacturing. Some part characteristics are 'tailor made' for this process. Selecting the right parts for the process is the first step to maximizing productivity gains. We will also present specific lessons we learned about feature geometry that can and cannot be produced using additive manufacturing machines. Most liquid engine components were made using a two-step process. The base part was made using additive manufacturing and then traditional machining processes were used to produce the final part. The presentation will describe design accommodations needed to make the base part and lessons we learned about which features could be built directly and which require the final machine process. Tolerance capabilities, surface finish, and material thickness allowances will also be covered. Additive Manufacturing can produce internal passages that cannot be made using traditional approaches. It can also eliminate a significant amount of manpower by reducing part count and leveraging model-based design and analysis techniques. Information will be shared about performance enhancements and design efficiencies we experienced for certain categories of engine parts.

Building Habitats on the Moon: Engineering Approaches to Lunar Settlements

NASA Astrophysics Data System (ADS)

Benaroya, H.

This book provides an overview of various concepts for lunar habitats and structural designs and characterizes the lunar environment - the technical and the nontechnical. The designs take into consideration psychological comfort, structural strength against seismic and thermal activity, as well as internal pressurization and 1/6 g. Also discussed are micrometeoroid modelling, risk and redundancy as well as probability and reliability, with an introduction to analytical tools that can be useful in modelling uncertainties.

Conceptual design studies for surface infrastructure

NASA Technical Reports Server (NTRS)

Bufkin, Ann L.; Jones, William R., II

1986-01-01

The utimate design of a manned Mars base will be the result of considerable engineering analysis and many trade studies to optimize the configuration. Many options and scenarios are available and all need to be considered at this time. Initial base elements, two base configuration concepts, internal space architectural concerns, and two base set-up scenarios are discussed. There are many variables as well as many unknowns to be reckoned with before people set foot on the red planet.

Mission Peculiar Equipment (MPE) For Spacelab Mission 1 Payload

NASA Astrophysics Data System (ADS)

Sims, John H.; Dodeck, Hauke

1982-02-01

Spacelab interfaces and services for payloads are advertised in the Spacelab Payload Accommodations Handbook (SPAH). These accommodations are available to the total payload and must be managed and apportioned by a payload integrator. A major part of the integration task is satisfying all instruments/facilities servicing requirements which vary with each item of payload equipment and, when totalled, sometimes exceed the capabilities as defined in SPAH. Such a determination is an output of the integrated payload design and integration effort which consists of analytical assessments based on individual payload equipment requirements inputs, STS and Spacelab available accommodations and constraints, and programmatic considerations. This systems engineering activity spans all engineering disciplines, assesses the module and pallet layouts and simultaneous operation of instrument/facility combinations, and requires a detailed knowledge of the Spacelab design. Introduction of a broad range of payload integrator-provided Mission Peculiar Equipment (MPE) into the Spacelab Mission 1 payload complement was necessary to be added to the Spacelab provisions in order to satisfy the interface and service requirements for each payload developer. This paper provides insight into various aspects of this MPE; including why it is needed, driving design considerations, design and development problems, and conclusions and recommendations for the future. MPE identified for Spacelab Mission 1 begins an inventory that will continue to expand as other mission requirements are identified and the Spacelab flight frequency increases.

Augmenting endogenous repair of soft tissues with nanofibre scaffolds

PubMed Central

Snelling, Sarah; Dakin, Stephanie; Carr, Andrew

2018-01-01

As our ability to engineer nanoscale materials has developed we can now influence endogenous cellular processes with increasing precision. Consequently, the use of biomaterials to induce and guide the repair and regeneration of tissues is a rapidly developing area. This review focuses on soft tissue engineering, it will discuss the types of biomaterial scaffolds available before exploring physical, chemical and biological modifications to synthetic scaffolds. We will consider how these properties, in combination, can provide a precise design process, with the potential to meet the requirements of the injured and diseased soft tissue niche. Finally, we frame our discussions within clinical trial design and the regulatory framework, the consideration of which is fundamental to the successful translation of new biomaterials. PMID:29695606

Effects of process parameters in plastic, metal, and ceramic injection molding processes

NASA Astrophysics Data System (ADS)

Lee, Shi W.; Ahn, Seokyoung; Whang, Chul Jin; Park, Seong Jin; Atre, Sundar V.; Kim, Jookwon; German, Randall M.

2011-09-01

Plastic injection molding has been widely used in the past and is a dominant forming approach today. As the customer demands require materials with better engineering properties that were not feasible with polymers, powder injection molding with metal and ceramic powders has received considerable attention in recent decades. To better understand the differences in the plastic injection molding, metal injection molding, and ceramic injection molding, the effects of the core process parameters on the process performances has been studied using the state-of-the-art computer-aided engineering (CAE) design tool, PIMSolver® The design of experiments has been conducted using the Taguchi method to obtain the relative contributions of various process parameters onto the successful operations.

Skin Bioprinting: Impending Reality or Fantasy?

PubMed

Ng, Wei Long; Wang, Shuai; Yeong, Wai Yee; Naing, May Win

2016-09-01

Bioprinting provides a fully automated and advanced platform that facilitates the simultaneous and highly specific deposition of multiple types of skin cells and biomaterials, a process that is lacking in conventional skin tissue-engineering approaches. Here, we provide a realistic, current overview of skin bioprinting, distinguishing facts from myths. We present an in-depth analysis of both current skin bioprinting works and the cellular and matrix components of native human skin. We also highlight current limitations and achievements, followed by design considerations and a future outlook for skin bioprinting. The potential of bioprinting with converging opportunities in biology, material, and computational design will eventually facilitate the fabrication of improved tissue-engineered (TE) skin constructs, making bioprinting skin an impending reality. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modular disposable can (MODCAN) crash cushion: A concept investigation

NASA Technical Reports Server (NTRS)

Knoell, A.; Wilson, A.

1976-01-01

A conceptual design investigation of an improved highway crash cushion system is presented. The system is referred to as a modular disposable can (MODCAN) crash system. It is composed of a modular arrangement of disposable metal beverage cans configured to serve as an effective highway impact attenuation system. Experimental data, design considerations, and engineering calculations supporting the design development are presented. Design performance is compared to that of a conventional steel drum system. It is shown that the MODCAN concepts offers the potential for smoother and safer occupant deceleration for a larger class of vehicle impact weights than the steel drum device.

Report of the Working Design Group

NASA Technical Reports Server (NTRS)

1992-01-01

The engineering study group in the LOUISA workshop was responsible for producing a preliminary general design for an optical synthetic aperture telescope on the Moon. This design is intended to be a test case for focusing continuing design studies. The scope of the design included consideration of the array geometry, individual telescopes, metrology, site attributes, and construction. However, no attempt was made to go into further depth in the design than to cover the essential characteristics of the instrument. The starting point for the array design was the lunar optical array discussed by Burke (1985). His array geometry followed the design and correlation procedure of the 27-element Very Large Array (VLA) radio telescopes near Socorro, New Mexico.

Leachate management design in Mexico

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

Lange, D.A.; Broscious, J.C.; Zullo, E.G.

1996-02-01

As part of a project to provide solid waste master plans for 25 cities in Mexico, an American engineering firm, Paul C. Rizzo Associates (Monroeville, Pa.), was contracted to design a comprehensive leachate management system for landfills in the chosen cities. The solid waste master plan project was administered by the Mexican federal government Secretaria de Desarrollo Social (SEDESOL) with funding from the World Bank. While Paul C. Rizzo was the prime contractor for the project, which was completed in 1994, work was also subcontracted to a local Mexican engineering firm. The lack of specific design criteria for leachate managementmore » in current Mexican regulations enabled the use of a creative design for the system based on experience and technical judgment. Important design considerations included the current, primitive open-dump/burning/scavenging method of disposal and recycling of wastes, and the need for a minimal-cost solution in this developing country. The economic situation made the need for minimal expenditures to upgrade infrastructure equally important. The purpose of the design effort was to use evaporation and recirculation methods of landfill leachate management to minimize the amount of leachate that required treatment. Engineers in the project sought an ultimate goal of achieving zero excess leachate at the landfill sites.« less

Design Considerations of ISTAR Hydrocarbon Fueled Combustor Operating in Air Augmented Rocket, Ramjet and Scramjet Modes

NASA Technical Reports Server (NTRS)

Andreadis, Dean; Drake, Alan; Garrett, Joseph L.; Gettinger, Christopher D.; Hoxie, Stephen S.

2003-01-01

The development and ground test of a rocket-based combined cycle (RBCC) propulsion system is being conducted as part of the NASA Marshall Space Flight Center (MSFC) Integrated System Test of an Airbreathing Rocket (ISTAR) program. The eventual flight vehicle (X-43B) is designed to support an air-launched self-powered Mach 0.7 to 7.0 demonstration of an RBCC engine through all of its airbreathing propulsion modes - air augmented rocket (AAR), ramjet (RJ), and scramjet (SJ). Through the use of analytical tools, numerical simulations, and experimental tests the ISTAR program is developing and validating a hydrocarbon-fueled RBCC combustor design methodology. This methodology will then be used to design an integrated RBCC propulsion system that produces robust ignition and combustion stability characteristics while maximizing combustion efficiency and minimizing drag losses. First order analytical and numerical methods used to design hydrocarbon-fueled combustors are discussed with emphasis on the methods and determination of requirements necessary to establish engine operability and performance characteristics.

Design Considerations of Istar Hydrocarbon Fueled Combustor Operating in Air Augmented Rocket, Ramjet and Scramjet Modes

NASA Technical Reports Server (NTRS)

Andreadis, Dean; Drake, Alan; Garrett, Joseph L.; Gettinger, Christopher D.; Hoxie, Stephen S.

2002-01-01

The development and ground test of a rocket-based combined cycle (RBCC) propulsion system is being conducted as part of the NASA Marshall Space Flight Center (MSFC) Integrated System Test of an Airbreathing Rocket (ISTAR) program. The eventual flight vehicle (X-43B) is designed to support an air-launched self-powered Mach 0.7 to 7.0 demonstration of an RBCC engine through all of its airbreathing propulsion modes - air augmented rocket (AAR), ramjet (RJ), and scramjet (SJ). Through the use of analytical tools, numerical simulations, and experimental tests the ISTAR program is developing and validating a hydrocarbon-fueled RBCC combustor design methodology. This methodology will then be used to design an integrated RBCC propulsion system thai: produces robust ignition and combustion stability characteristics while maximizing combustion efficiency and minimizing drag losses. First order analytical and numerical methods used to design hydrocarbon-fueled combustors are discussed with emphasis on the methods and determination of requirements necessary to establish engine operability and performance characteristics.

Nucleic Acid Engineering: RNA Following the Trail of DNA.

PubMed

Kim, Hyejin; Park, Yongkuk; Kim, Jieun; Jeong, Jaepil; Han, Sangwoo; Lee, Jae Sung; Lee, Jong Bum

2016-02-08

The self-assembly feature of the naturally occurring biopolymer, DNA, has fascinated researchers in the fields of materials science and bioengineering. With the improved understanding of the chemical and structural nature of DNA, DNA-based constructs have been designed and fabricated from two-dimensional arbitrary shapes to reconfigurable three-dimensional nanodevices. Although DNA has been used successfully as a building block in a finely organized and controlled manner, its applications need to be explored. Hence, with the myriad of biological functions, RNA has recently attracted considerable attention to further the application of nucleic acid-based structures. This Review categorizes different approaches of engineering nucleic acid-based structures and introduces the concepts, principles, and applications of each technique, focusing on how DNA engineering is applied as a guide to RNA engineering.

Concepts for Distributed Engine Control

NASA Technical Reports Server (NTRS)

Culley, Dennis E.; Thomas, Randy; Saus, Joseph

2007-01-01

Gas turbine engines for aero-propulsion systems are found to be highly optimized machines after over 70 years of development. Still, additional performance improvements are sought while reduction in the overall cost is increasingly a driving factor. Control systems play a vitally important part in these metrics but are severely constrained by the operating environment and the consequences of system failure. The considerable challenges facing future engine control system design have been investigated. A preliminary analysis has been conducted of the potential benefits of distributed control architecture when applied to aero-engines. In particular, reductions in size, weight, and cost of the control system are possible. NASA is conducting research to further explore these benefits, with emphasis on the particular benefits enabled by high temperature electronics and an open-systems approach to standardized communications interfaces.

Reduction of aircraft gas turbine engine pollutant emissions

NASA Technical Reports Server (NTRS)

Diehl, L. A.

1978-01-01

To accomplish simultaneous reduction of unburned hydrocarbons, carbon monoxide, and oxides of nitrogen, required major modifications to the combustor. The modification most commonly used was a staged combustion technique. While these designs are more complicated than production combustors, no insurmountable operational difficulties were encountered in either high pressure rig or engine tests which could not be resolved with additional normal development. The emission reduction results indicate that reductions in unburned hydrocarbons were sufficient to satisfy both near and far-termed EPA requirements. Although substantial reductions were observed, the success in achieving the CO and NOx standards was mixed and depended heavily on the engine/engine cycle on which it was employed. Technology for near term CO reduction was satisfactory or marginally satisfactory. Considerable doubt exists if this technology will satisfy all far-term requirements.

How do the Polytechnic Students Cope with the Difficulties in Composing Abstracts for Their Final Projects?

NASA Astrophysics Data System (ADS)

Niswatin, C.; Latief, M. A.; Suharyadi, S.

2018-02-01

This research aims to uncover the fact about engineering students in dealing with composing abstracts for their final projects. The research applies a descriptive qualitative quantitative design. The data were collected through questioners involving 104 engineering students, including the alumni at Politeknik Kota Malang, Indonesia. Furthermore, interviews were carried out to explain the details where necessary to support the primary data. It is found that the common problems faced by engineering students include 1) combining words into sentences, 2) identifying the most appropriate technical terms in engineering, and 3) applying grammar in context. To cope with those difficulties they demanded translation application machines, supported by peer-proofreaders. In addition, they considerably engaged personal tutoring with the lectures more than three times.

Clinical Immersion and Biomedical Engineering Design Education: "Engineering Grand Rounds".

PubMed

Walker, Matthew; Churchwell, André L

2016-03-01

Grand Rounds is a ritual of medical education and inpatient care comprised of presenting the medical problems and treatment of a patient to an audience of physicians, residents, and medical students. Traditionally, the patient would be in attendance for the presentation and would answer questions. Grand Rounds has evolved considerably over the years with most sessions being didactic-rarely having a patient present (although, in some instances, an actor will portray the patient). Other members of the team, such as nurses, nurse practitioners, and biomedical engineers, are not traditionally involved in the formal teaching process. In this study we examine the rapid ideation in a clinical setting to forge a system of cross talk between engineers and physicians as a steady state at the praxis of ideation and implementation.

Detailed technical plan for Test Program Element-III (TPE-III) of the first wall/blanket shield engineering test program

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

Turner, L.R.; Praeg, W.F.

1982-03-01

The experimental requirements, test-bed design, and computational requirements are reviewed and updated. Next, in Sections 3, 4 and 5, the experimental plan, instrumentation, and computer plan, respectively, are described. Finally, Section 6 treats other considerations, such as personnel, outside participation, and distribution of results.

Wanted for 21st Century Schools: Renaissance STEM Teacher Preferred

ERIC Educational Resources Information Center

Ames, Tyler; Reeve, Edward; Stewardson, Gary; Lott, Kimberly

2017-01-01

As education seeks to mold itself to fit the demands of the 21st century, STEM education will continue to be an important consideration. The integrated and crosscutting nature of STEM is incorporated into the "Next Generation Science Standards" in which engineering design is raised to the same level as scientific inquiry and is expected…

DEBLICOM: Deaf-Blind Communication and Control Systems. Interim Progress Report, August 1974-August 1975.

ERIC Educational Resources Information Center

Kafafian, Haig

Presented is a report on the work of Cybernetics Research Institute (CRI) investigators on the development of deaf-blind communication and control systems (DEBLICOM). Described in Part One is one embodiment of DEBLICOM designed and built by CRI engineers. Reported in Part Two are experimental procedures and human factors considerations of…

Re-Engineering Information Technology: Design Considerations for Competency Education. CompetencyWorks Issue Brief

ERIC Educational Resources Information Center

Glowa, Liz

2013-01-01

Competency education is student-centric, personalizing student progress so that every child has adequate time and support to reach proficiency every step of the way. Competency education fundamentally changes the way the educational enterprise is organized around student needs, and thus must have a dynamic IT system to support it. Following an…

Research flight software engineering and MUST, an integrated system of support tools

NASA Technical Reports Server (NTRS)

Straeter, T. A.; Foudriat, E. C.; Will, R. W.

1977-01-01

Consideration is given to software development to support NASA flight research. The Multipurpose User-Oriented Software Technology (MUST) program, designed to integrate digital systems into flight research, is discussed. Particular attention is given to the program's special interactive user interface, subroutine library, assemblers, compiler, automatic documentation tools, and test and simulation subsystems.

DEVELOPMENT OF OPERATIONAL CONCEPTS FOR ADVANCED SMRs: THE ROLE OF COGNITIVE SYSTEMS ENGINEERING

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

Jacques Hugo; David Gertman

Advanced small modular reactors (AdvSMRs) will use advanced digital instrumentation and control systems, and make greater use of automation. These advances not only pose technical and operational challenges, but will inevitably have an effect on the operating and maintenance (O&M) cost of new plants. However, there is much uncertainty about the impact of AdvSMR designs on operational and human factors considerations, such as workload, situation awareness, human reliability, staffing levels, and the appropriate allocation of functions between the crew and various automated plant systems. Existing human factors and systems engineering design standards and methodologies are not current in terms ofmore » human interaction requirements for dynamic automated systems and are no longer suitable for the analysis of evolving operational concepts. New models and guidance for operational concepts for complex socio-technical systems need to adopt a state-of-the-art approach such as Cognitive Systems Engineering (CSE) that gives due consideration to the role of personnel. This approach we report on helps to identify and evaluate human challenges related to non-traditional concepts of operations. A framework - defining operational strategies was developed based on the operational analysis of Argonne National Laboratory’s Experimental Breeder Reactor-II (EBR-II), a small (20MWe) sodium-cooled reactor that was successfully operated for thirty years. Insights from the application of the systematic application of the methodology and its utility are reviewed and arguments for the formal adoption of CSE as a value-added part of the Systems Engineering process are presented.« less

User-centered requirements engineering in health information systems: a study in the hemophilia field.

PubMed

Teixeira, Leonor; Ferreira, Carlos; Santos, Beatriz Sousa

2012-06-01

The use of sophisticated information and communication technologies (ICTs) in the health care domain is a way to improve the quality of services. However, there are also hazards associated with the introduction of ICTs in this domain and a great number of projects have failed due to the lack of systematic consideration of human and other non-technology issues throughout the design or implementation process, particularly in the requirements engineering process. This paper presents the methodological approach followed in the design process of a web-based information system (WbIS) for managing the clinical information in hemophilia care, which integrates the values and practices of user-centered design (UCD) activities into the principles of software engineering, particularly in the phase of requirements engineering (RE). This process followed a paradigm that combines a grounded theory for data collection with an evolutionary design based on constant development and refinement of the generic domain model using three well-known methodological approaches: (a) object-oriented system analysis; (b) task analysis; and, (c) prototyping, in a triangulation work. This approach seems to be a good solution for the requirements engineering process in this particular case of the health care domain, since the inherent weaknesses of individual methods are reduced, and emergent requirements are easier to elicit. Moreover, the requirements triangulation matrix gives the opportunity to look across the results of all used methods and decide what requirements are critical for the system success. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Genome Engineering and Modification Toward Synthetic Biology for the Production of Antibiotics.

PubMed

Zou, Xuan; Wang, Lianrong; Li, Zhiqiang; Luo, Jie; Wang, Yunfu; Deng, Zixin; Du, Shiming; Chen, Shi

2018-01-01

Antibiotic production is often governed by large gene clusters composed of genes related to antibiotic scaffold synthesis, tailoring, regulation, and resistance. With the expansion of genome sequencing, a considerable number of antibiotic gene clusters has been isolated and characterized. The emerging genome engineering techniques make it possible towards more efficient engineering of antibiotics. In addition to genomic editing, multiple synthetic biology approaches have been developed for the exploration and improvement of antibiotic natural products. Here, we review the progress in the development of these genome editing techniques used to engineer new antibiotics, focusing on three aspects of genome engineering: direct cloning of large genomic fragments, genome engineering of gene clusters, and regulation of gene cluster expression. This review will not only summarize the current uses of genomic engineering techniques for cloning and assembly of antibiotic gene clusters or for altering antibiotic synthetic pathways but will also provide perspectives on the future directions of rebuilding biological systems for the design of novel antibiotics. © 2017 Wiley Periodicals, Inc.

Gaining the Competitive Edge: Design for Manufacturing

NASA Technical Reports Server (NTRS)

Batill, Stephen M.; Pinkelman, Jim; Sellar, Richard

1993-01-01

The successful design of a commercial aircraft which is intended to be in direct competition with existing aircraft requires a market analysis to establish design requirements, the development of a concept to achieve those goals. and the ability to economically manufacture the aircraft. It is often the case that an engineer designs system components with only the perspective of a particular discipline. The relationship of that component to the entire system is often a minor consideration. In an effort to highlight the interaction that is necessary during the design process, the students were organized into design/build teams and required to integrate aspects of market analysis, engineering design, production and economics into their concepts. In order to facilitate this process a hypothetical "Aeroworld" was established. Having been furnished relevant demographic and economic data for "Aeroworld". students were given the task of designing and building an aircraft for a specific market while achieving an economically competitive design. Involvement of the team in the evolution of the design from market definition to technical development to manufacturing allowed the students to identify critical issues in the design process and to encounter many of the conflicting requirements which arise in an aerospace systems design.

Hybrid computational and experimental approach for the study and optimization of mechanical components

NASA Astrophysics Data System (ADS)

Furlong, Cosme; Pryputniewicz, Ryszard J.

1998-05-01

Increased demands on the performance and efficiency of mechanical components impose challenges on their engineering design and optimization, especially when new and more demanding applications must be developed in relatively short periods of time while satisfying design objectives, as well as cost and manufacturability. In addition, reliability and durability must be taken into consideration. As a consequence, effective quantitative methodologies, computational and experimental, should be applied in the study and optimization of mechanical components. Computational investigations enable parametric studies and the determination of critical engineering design conditions, while experimental investigations, especially those using optical techniques, provide qualitative and quantitative information on the actual response of the structure of interest to the applied load and boundary conditions. We discuss a hybrid experimental and computational approach for investigation and optimization of mechanical components. The approach is based on analytical, computational, and experimental resolutions methodologies in the form of computational, noninvasive optical techniques, and fringe prediction analysis tools. Practical application of the hybrid approach is illustrated with representative examples that demonstrate the viability of the approach as an effective engineering tool for analysis and optimization.

Design and upgrades for the Sloan Digital Sky Survey telescope's roll-off enclosure

NASA Astrophysics Data System (ADS)

Leger, R. French; Long, Dan; Klaene, Mark A.

2003-02-01

The SDSS telescope is housed, when not in use, in a roll-off enclosure. This enclosure rolls away from the telescope a distance of 60 feet, leaving the telescope fully exposed for operations. Design considerations for wind and solar loading, thermal venting, conditioning and stability are reviewed. Originally, the enclosure had been constructed to minimize its surface area obstruction to the telescopes field of view. This design feature, however, offered little room to perform engineering tasks during non-operational time. An upgrade to the structure, in the form of raising the roof, was instituted. This improvement greatly enhanced the engineering and testing functions performed on the telescope, thereby increasing operational efficiency and the time allotted to engineering tasks. Problems maintaining and associated with weather sealing, lightning protection, truck wheel alignment, altitude effects on truck controllers and thermal conditioning are examined. Communication and electrical connections between stationary and moving elements of the enclosure are described. Two types of systems, to date, have been used one a reel and the other a slider system. Advantages and disadvantages of both are examined from the perspective of four years experience.

Evolution of Nickel-titanium Alloys in Endodontics.

PubMed

Ounsi, Hani F; Nassif, Wadih; Grandini, Simone; Salameh, Ziad; Neelakantan, Prasanna; Anil, Sukumaran

2017-11-01

To improve clinical use of nickel-titanium (NiTi) endodontic rotary instruments by better understanding the alloys that compose them. A large number of engine-driven NiTi shaping instruments already exists on the market and newer generations are being introduced regularly. While emphasis is being put on design and technique, manufacturers are more discreet about alloy characteristics that dictate instrument behavior. Along with design and technique, alloy characteristics of endodontic instruments is one of the main variables affecting clinical performance. Modification in NiTi alloys is numerous and may yield improvements, but also drawbacks. Martensitic instruments seem to display better cyclic fatigue properties at the expense of surface hardness, prompting the need for surface treatments. On the contrary, such surface treatments may improve cutting efficiency but are detrimental to the gain in cyclic fatigue resistance. Although the design of the instrument is vital, it should in no way cloud the importance of the properties of the alloy and how they influence the clinical behavior of NiTi instruments. Dentists are mostly clinicians rather than engineers. With the advances in instrumentation design and alloys, they have an obligation to deal more intimately with engineering consideration to not only take advantage of their possibilities but also acknowledge their limitations.

Radiation shielding estimates for manned Mars space flight.

PubMed

Dudkin, V E; Kovalev, E E; Kolomensky, A V; Sakovich, V A; Semenov, V F; Demin, V P; Benton, E V

1992-01-01

In the analysis of the required radiation shielding protection of spacecraft during a Mars flight, specific effects of solar activity (SA) on the intensity of galactic and solar cosmic rays were taken into consideration. Three spaceflight periods were considered: (1) maximum SA; (2) minimum SA; and (3) intermediate SA, when intensities of both galactic and solar cosmic rays are moderately high. Scenarios of spaceflights utilizing liquid-propellant rocket engines, low- and intermediate-thrust nuclear electrojet engines, and nuclear rocket engines, all of which have been designed in the Soviet Union, are reviewed. Calculations were performed on the basis of a set of standards for radiation protection approved by the U.S.S.R. State Committee for Standards. It was found that the lowest estimated mass of a Mars spacecraft, including the radiation shielding mass, obtained using a combination of a liquid propellant engine with low and intermediate thrust nuclear electrojet engines, would be 500-550 metric tons.

Cooling Duct Analysis for Transpiration/Film Cooled Liquid Propellant Rocket Engines

NASA Technical Reports Server (NTRS)

Micklow, Gerald J.

1996-01-01

The development of a low cost space transportation system requires that the propulsion system be reusable, have long life, with good performance and use low cost propellants. Improved performance can be achieved by operating the engine at higher pressure and temperature levels than previous designs. Increasing the chamber pressure and temperature, however, will increase wall heating rates. This necessitates the need for active cooling methods such as film cooling or transpiration cooling. But active cooling can reduce the net thrust of the engine and add considerably to the design complexity. Recently, a metal drawing process has been patented where it is possible to fabricate plates with very small holes with high uniformity with a closely specified porosity. Such a metal plate could be used for an inexpensive transpiration/film cooled liner to meet the demands of advanced reusable rocket engines, if coolant mass flow rates could be controlled to satisfy wall cooling requirements and performance. The present study investigates the possibility of controlling the coolant mass flow rate through the porous material by simple non-active fluid dynamic means. The coolant will be supplied to the porous material by series of constant geometry slots machined on the exterior of the engine.

Ion Engine Plume Interaction Calculations for Prototypical Prometheus 1

NASA Technical Reports Server (NTRS)

Mandell, Myron J.; Kuharski, Robert A.; Gardner, Barbara M.; Katz, Ira; Randolph, Tom; Dougherty, Ryan; Ferguson, Dale C.

2005-01-01

Prometheus 1 is a conceptual mission to demonstrate the use of atomic energy for distant space missions. The hypothetical spacecraft design considered in this paper calls for multiple ion thrusters, each with considerably higher beam energy and beam current than have previously flown in space. The engineering challenges posed by such powerful thrusters relate not only to the thrusters themselves, but also to designing the spacecraft to avoid potentially deleterious effects of the thruster plumes. Accommodation of these thrusters requires good prediction of the highest angle portions of the main beam, as well as knowledge of clastically scattered and charge exchange ions, predictions for grid erosion and contamination of surfaces by eroded grid material, and effects of the plasma plume on radio transmissions. Nonlinear interactions of multiple thrusters are also of concern. In this paper we describe two- and three-dimensional calculations for plume structure and effects of conceptual Prometheus 1 ion engines. Many of the techniques used have been validated by application to ground test data for the NSTAR and NEXT ion engines. Predictions for plume structure and possible sputtering and contamination effects will be presented.

Towards the engineering of in vitro systems.

PubMed

Hold, Christoph; Panke, Sven

2009-08-06

Synthetic biology aims at rationally implementing biological systems from scratch. Given the complexity of living systems and our current lack of understanding of many aspects of living cells, this is a major undertaking. The design of in vitro systems can be considerably easier, because they can consist of fewer constituents, are quasi time invariant, their parameter space can be better accessed and they can be much more easily perturbed and then analysed chemically and mathematically. However, even for simplified in vitro systems, following a comprehensively rational design procedure is still difficult. When looking at a comparatively simple system, such as a medium-sized enzymatic reaction network as it is represented by glycolysis, major issues such as a lack of comprehensive enzyme kinetics and of suitable knowledge on crucial design parameters remain. Nevertheless, in vitro systems are very suitable to overcome these obstacles and therefore well placed to act as a stepping stone to engineering living systems.

Study of water supply & sanitation practices in India using geographic information systems: some design & other considerations in a village setting.

PubMed

Gopal, Srila; Sarkar, Rajiv; Banda, Kalyan; Govindarajan, Jeyanthi; Harijan, B B; Jeyakumar, M B; Mitta, Philip; Sadanala, M E; Selwyn, Tryphena; Suresh, C R; Thomas, V A; Devadason, Pethuru; Kumar, Ranjit; Selvapandian, David; Kang, Gagandeep; Balraj, Vinohar

2009-03-01

Availability of clean water and adequate sanitation facilities are of prime importance for limiting diarrhoeal diseases. We examined the water and sanitation facilities of a village in southern India using geographic information system (GIS) tools. Places of residence, water storage and distribution, sewage and places where people in the village defaecated were mapped and drinking water sources were tested for microbial contamination in Nelvoy village, Vellore district, Tamil Nadu. Water in the village was found to be microbiologically unfit for consumption. Analysis using direct observations supplemented by GIS maps revealed poor planning, poor engineering design and lack of policing of the water distribution system causing possible contamination of drinking water from sewage at multiple sites. Until appropriate engineering designs for water supply and sewage disposal to suit individual village needs are made available, point-of-use water disinfection methods could serve as an interim solution.

Magnetic bearings: A key technology for advanced rocket engines?

NASA Technical Reports Server (NTRS)

Girault, J. PH.

1992-01-01

For several years, active magnetic bearings (AMB) have demonstrated their capabilities in many fields, from industrial compressors to control wheel suspension for spacecraft. Despite this broad area, no significant advance has been observed in rocket propulsion turbomachinery, where size, efficiency, and cost are crucial design criteria. To this respect, Societe Europeenne de Propulsion (SEP) had funded for several years significant efforts to delineate the advantages and drawbacks of AMB applied to rocket propulsion systems. Objectives of this work, relative technological basis, and improvements are described and illustrated by advanced turbopump layouts. Profiting from the advantages of compact design in cryogenic environments, the designs show considerable improvements in engine life, performances, and reliability. However, these conclusions should still be tempered by high recurrent costs, mainly due to the space-rated electronics. Development work focused on this point and evolution of electronics show the possibility to decrease production costs by an order of magnitude.

A thermoacoustic Stirling heat engine

NASA Astrophysics Data System (ADS)

Backhaus, S.; Swift, G. W.

1999-05-01

Electrical and mechanical power, together with other forms of useful work, are generated worldwide at a rate of about 1012 watts, mostly using heat engines. The efficiency of such engines is limited by the laws of thermodynamics and by practical considerations such as the cost of building and operating them. Engines with high efficiency help to conserve fossil fuels and other natural resources, reducing global-warming emissions and pollutants. In practice, the highest efficiencies are obtained only in the most expensive, sophisticated engines, such as the turbines in central utility electrical plants. Here we demonstrate an inexpensive thermoacoustic engine that employs the inherently efficient Stirling cycle. The design is based on a simple acoustic apparatus with no moving parts. Our first small laboratory prototype, constructed using inexpensive hardware (steel pipes), achieves an efficiency of 0.30, which exceeds the values of 0.10-0.25 attained in other heat engines, with no moving parts. Moreover, the efficiency of our prototype is comparable to that of the common internal combustion engine (0.25-0.40) and piston-driven Stirling engines, (0.20-0.38).

Progress toward an optimized hydrogen series hybrid engine

NASA Astrophysics Data System (ADS)

Smith, J. Ray; Aceves, Salvador M.; Johnson, Norman L.; Amsden, Anthony A.

1995-06-01

The design considerations and computational fluid dynamics (CFD) modeling of a high efficiency, low emissions, hydrogen-fueled engine for use as the prime mover of a series hybrid automobile is described. The series hybrid automobile uses the engine to generate electrical energy via a lightweight generator, the electrical energy is stored in a power peaking device (like a flywheel or ultracapacitor) and used as required to meet the tractive drive requirements (plus accessory loads) through an electrical motor. The engine/generator is stopped whenever the energy storage device is fully charged. Engine power output required was determined with a vehicle simulation code to be 15 to 20 kW steady state with peak output of 40 to 45 kW for hill climb. Combustion chamber and engine geometry were determined from a critical review of the hydrogen engine experiments in the literature combined with a simplified global engine model. Two different engine models are employed to guide engine design. The models are a simplified global engine performance model that relies strongly on correlations with literature data for heat transfer and friction losses, and a state-of-the-art CFD combustion model, KIVA-3, to elucidate fluid mechanics and combustion details through full three-dimensional modeling. Both intake and exhaust processes as well as hydrogen combustion chemistry and thermal NO(sub x) production are simulated. Ultimately, a comparison between the simulation and experimental results will lead to improved modeling and will give guidance to changes required in the next generation engine to achieve the goal of 45% brake thermal efficiency.

Closed-Cycle Engine Program Used to Study Brayton Power Conversion

NASA Technical Reports Server (NTRS)

Johnson, Paul K.

2005-01-01

One form of power conversion under consideration in NASA Glenn Research Center's Thermal Energy Conversion Branch is the closed-Brayton-cycle engine. In the tens-of-kilowatts to multimegawatt class, the Brayton engine lends itself to potential space nuclear power applications such as electric propulsion or surface power. The Thermal Energy Conversion Branch has most recently concentrated its Brayton studies on electric propulsion for Prometheus. One piece of software used for evaluating such designs over a limited tradeoff space has been the Closed Cycle Engine Program (CCEP). The CCEP originated in the mid-1980s from a Fortran aircraft engine code known as the Navy/NASA Engine Program (NNEP). Components such as a solar collector, heat exchangers, ducting, a pumped-loop radiator, a nuclear heat source, and radial turbomachinery were added to NNEP, transforming it into a high-fidelity design and performance tool for closed-Brayton-cycle power conversion and heat rejection. CCEP was used in the 1990s in conjunction with the Solar Dynamic Ground Test Demonstration conducted at Glenn. Over the past year, updates were made to CCEP to adapt it for an electric propulsion application. The pumped-loop radiator coolant can now be n-heptane, water, or sodium-potassium (NaK); liquid-metal pump design tables were added to accommodate the NaK fluid. For the reactor and shield, a user can now elect to calculate a higher fidelity mass estimate. In addition, helium-xenon working-fluid properties were recalculated and updated.

Engineering education for youth: Diverse elementary school students' experiences with engineering design

NASA Astrophysics Data System (ADS)

Hegedus, Theresa

Lingering concerns over the persistent achievement gap amidst the trend of an increasingly diverse society have been compounded by calls from the Oval Office, the National Science Board, and nationwide media to also address our current creativity crisis. Now, more than ever, we have a responsibility to produce a STEM-capable (science, technology, engineering, and mathematics) workforce to meet the demands of our rapidly changing local and global economic landscape. Barriers exist in our traditional educational system, which has historically limited underrepresented groups' affiliation and membership in the disciplines of science and engineering. The recent incorporation of engineering into the latest science education reform efforts presents an opportunity to expose students as early as elementary school to engineering practices and habits of mind, which have the potential to stimulate creative thinking skills through engineering design. This qualitative study was designed to examine the ways in which engineering education has the potential to promote creativity and academic competence in elementary science classrooms. As a part of my study, a diverse group of students from two fifth-grade classrooms took part in a 10-12 hour, engineering-based curriculum unit (Engineering is Elementary) during their regular science instructional time. Using a sociocultural lens, to include cultural production and identities in practice as part of my framework, I analyzed group and individual performances through classroom observations, student interviews, and teacher reflections to better understand the meaning students made of their experiences with engineering. Findings from the study included the ways in which creativity was culturally produced in the classroom to include: 1) idea generation; 2) design and innovation; 3) gumption/resourcefulness; and 4) social value. Opportunities for collaboration increased through each stage of the unit culminating with the design challenge. Engineering teams required cultivation by the teacher as students negotiated spaces for collaboration through challenges of competition versus compromise; assumed versus assigned roles; management of verbal versus non-verbal communication; and shifts from teacher-as-authority-figure to peers as sources of knowledge and inspiration. The engineering design challenge provided an ideal context for broaching socio-scientific issues and attention to ethical considerations. Students made reference to their growing environmental awareness and developing moral reasoning in their definitions and reflections on green engineering. Throughout the course of the unit, successful students, struggling students, and students with uncertain trajectories established themselves as competent and efficacious engineers. Implications of the study include ways to assist teachers in recognizing and cultivating creativity and collaboration in addition to effectively incorporating socio-scientific issues as part of the engineering (and science) curriculum. I also present recommendations for promoting equity in classroom engineering, pre-service teacher initiatives, and strategies for capitalizing on the complementarity between science and engineering.

A Methodology to Assess the Capability of Engine Designs to Meet Closed-Loop Performance and Operability Requirements

NASA Technical Reports Server (NTRS)

Zinnecker, Alicia M.; Csank, Jeffrey

2015-01-01

Designing a closed-loop controller for an engine requires balancing trade-offs between performance and operability of the system. One such trade-off is the relationship between the 95 percent response time and minimum high-pressure compressor (HPC) surge margin (SM) attained during acceleration from idle to takeoff power. Assuming a controller has been designed to meet some specification on response time and minimum HPC SM for a mid-life (nominal) engine, there is no guarantee that these limits will not be violated as the engine ages, particularly as it reaches the end of its life. A characterization for the uncertainty in this closed-loop system due to aging is proposed that defines elliptical boundaries to estimate worst-case performance levels for a given control design point. The results of this characterization can be used to identify limiting design points that bound the possible controller designs yielding transient results that do not exceed specified limits in response time or minimum HPC SM. This characterization involves performing Monte Carlo simulation of the closed-loop system with controller constructed for a set of trial design points and developing curve fits to describe the size and orientation of each ellipse; a binary search procedure is then employed that uses these fits to identify the limiting design point. The method is demonstrated through application to a generic turbofan engine model in closed-loop with a simplified controller; it is found that the limit for which each controller was designed was exceeded by less than 4.76 percent. Extension of the characterization to another trade-off, that between the maximum high-pressure turbine (HPT) entrance temperature and minimum HPC SM, showed even better results: the maximum HPT temperature was estimated within 0.76 percent. Because of the accuracy in this estimation, this suggests another limit that may be taken into consideration during design and analysis. It also demonstrates the extension of the characterization to other attributes that contribute to the performance or operability of the engine. Metrics are proposed that, together, provide information on the shape of the trade-off between response time and minimum HPC SM, and how much each varies throughout the life cycle, at the limiting design points. These metrics also facilitate comparison of the expected transient behavior for multiple engine models.

A Methodology to Assess the Capability of Engine Designs to Meet Closed-loop Performance and Operability Requirements

NASA Technical Reports Server (NTRS)

Zinnecker, Alicia M.; Csank, Jeffrey T.

2015-01-01

Designing a closed-loop controller for an engine requires balancing trade-offs between performance and operability of the system. One such trade-off is the relationship between the 95% response time and minimum high-pressure compressor (HPC) surge margin (SM) attained during acceleration from idle to takeoff power. Assuming a controller has been designed to meet some specification on response time and minimum HPC SM for a mid-life (nominal) engine, there is no guarantee that these limits will not be violated as the engine ages, particularly as it reaches the end of its life. A characterization for the uncertainty in this closed-loop system due to aging is proposed that defines elliptical boundaries to estimate worst-case performance levels for a given control design point. The results of this characterization can be used to identify limiting design points that bound the possible con- troller designs yielding transient results that do not exceed specified limits in response time or minimum HPC SM. This characterization involves performing Monte Carlo simulation of the closed-loop system with controller constructed for a set of trial design points and developing curve fits to describe the size and orientation of each ellipse; a binary search procedure is then employed that uses these fits to identify the limiting design point. The method is demonstrated through application to a generic turbofan engine model in closed- loop with a simplified controller; it is found that the limit for which each controller was designed was exceeded by less than 4.76%. Extension of the characterization to another trade-off, that between the maximum high-pressure turbine (HPT) entrance temperature and minimum HPC SM, showed even better results: the maximum HPT temperature was estimated within 0.76%. Because of the accuracy in this estimation, this suggests another limit that may be taken into consideration during design and analysis. It also demonstrates the extension of the characterization to other attributes that contribute to the performance or operability of the engine. Metrics are proposed that, together, provide information on the shape of the trade-off between response time and minimum HPC SM, and how much each varies throughout the life cycle, at the limiting design points. These metrics also facilitate comparison of the expected transient behavior for multiple engine models.

Rosetta:MSF: a modular framework for multi-state computational protein design.

PubMed

Löffler, Patrick; Schmitz, Samuel; Hupfeld, Enrico; Sterner, Reinhard; Merkl, Rainer

2017-06-01

Computational protein design (CPD) is a powerful technique to engineer existing proteins or to design novel ones that display desired properties. Rosetta is a software suite including algorithms for computational modeling and analysis of protein structures and offers many elaborate protocols created to solve highly specific tasks of protein engineering. Most of Rosetta's protocols optimize sequences based on a single conformation (i. e. design state). However, challenging CPD objectives like multi-specificity design or the concurrent consideration of positive and negative design goals demand the simultaneous assessment of multiple states. This is why we have developed the multi-state framework MSF that facilitates the implementation of Rosetta's single-state protocols in a multi-state environment and made available two frequently used protocols. Utilizing MSF, we demonstrated for one of these protocols that multi-state design yields a 15% higher performance than single-state design on a ligand-binding benchmark consisting of structural conformations. With this protocol, we designed de novo nine retro-aldolases on a conformational ensemble deduced from a (βα)8-barrel protein. All variants displayed measurable catalytic activity, testifying to a high success rate for this concept of multi-state enzyme design.

Rosetta:MSF: a modular framework for multi-state computational protein design

PubMed Central

Hupfeld, Enrico; Sterner, Reinhard

2017-01-01

Computational protein design (CPD) is a powerful technique to engineer existing proteins or to design novel ones that display desired properties. Rosetta is a software suite including algorithms for computational modeling and analysis of protein structures and offers many elaborate protocols created to solve highly specific tasks of protein engineering. Most of Rosetta’s protocols optimize sequences based on a single conformation (i. e. design state). However, challenging CPD objectives like multi-specificity design or the concurrent consideration of positive and negative design goals demand the simultaneous assessment of multiple states. This is why we have developed the multi-state framework MSF that facilitates the implementation of Rosetta’s single-state protocols in a multi-state environment and made available two frequently used protocols. Utilizing MSF, we demonstrated for one of these protocols that multi-state design yields a 15% higher performance than single-state design on a ligand-binding benchmark consisting of structural conformations. With this protocol, we designed de novo nine retro-aldolases on a conformational ensemble deduced from a (βα)8-barrel protein. All variants displayed measurable catalytic activity, testifying to a high success rate for this concept of multi-state enzyme design. PMID:28604768

An Example of Risk Informed Design

NASA Technical Reports Server (NTRS)

Banke, Rick; Grant, Warren; Wilson, Paul

2014-01-01

NASA Engineering requested a Probabilistic Risk Assessment (PRA) to compare the difference in the risk of Loss of Crew (LOC) and Loss of Mission (LOM) between different designs of a fluid assembly. They were concerned that the configuration favored by the design team was more susceptible to leakage than a second proposed design, but realized that a quantitative analysis to compare the risks between the two designs might strengthen their argument. The analysis showed that while the second design did help improve the probability of LOC, it did not help from a probability of LOM perspective. This drove the analysis team to propose a minor design change that would drive the probability of LOM down considerably. The analysis also demonstrated that there was another major risk driver that was not immediately obvious from a typical engineering study of the design and was therefore unexpected. None of the proposed alternatives were addressing this risk. This type of trade study demonstrates the importance of performing a PRA in order to completely understand a system's design. It allows managers to use risk as another one of the commodities (e.g., mass, cost, schedule, fault tolerance) that can be traded early in the design of a new system.

Artificial gravity studies and design considerations for Space Station centrifuges

NASA Technical Reports Server (NTRS)

Halstead, T. W.; Brown, A. H.; Fuller, C. A.; Oyama, J.

1984-01-01

The requirements to and capabilities of a Space Station biological facility centrifuge are discussed on the basis of an assessment of the objectives and subjects of future microgravity biological experiments. It is argued that the facility should be capable of both acute and extended chronic exposure of test subjects and biological materials to altered-g loading. In addition, the experimental approaches and equipment for microgravity studies on a Space Station are outlined. Finally, the engineering requirements of such a centrifuge are examined, with consideration of radial gravity gradients, size, and physical access to animals.

Recommended Practice for Use of Emissive Probes in Electric Propulsion Testing

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

Sheehan, J. P.; Raitses, Yevgeny; Hershkowitz, Noah

Here, this article provides recommended methods for building, operating, and taking plasma potential measurements from electron-emitting probes in electric propulsion devices, including Hall thrusters, gridded ion engines, and others. The two major techniques, the floating point technique and the inflection point technique, are described in detail as well as calibration and error-reduction methods. The major heating methods are described as well as the various considerations for emissive probe construction. Lastly, special considerations for electric propulsion plasmas are addressed, including high-energy densities, ion flows, magnetic fields, and potential fluctuations. Recommendations for probe design and operation are provided.

International standards on working postures and movements ISO 11226 and EN 1005-4.

PubMed

Delleman, N J; Dul, J

2007-11-01

Standards organizations have given considerable attention to the problem of work-related musculoskeletal disorders. The publication of international standards for evaluating working postures and movements, ISO 11,226 in 2000 and EN 1,005-4 in 2005, may be considered as a support for those involved in preventing and controlling these disorders. The first one is a tool for evaluation of existing work situations, whereas the latter one is a tool for evaluation during a design/engineering process. Key publications and considerations that led to the content of the standards are presented, followed by examples of application.

Recommended Practice for Use of Emissive Probes in Electric Propulsion Testing

DOE PAGES

Sheehan, J. P.; Raitses, Yevgeny; Hershkowitz, Noah; ...

2016-11-03

Here, this article provides recommended methods for building, operating, and taking plasma potential measurements from electron-emitting probes in electric propulsion devices, including Hall thrusters, gridded ion engines, and others. The two major techniques, the floating point technique and the inflection point technique, are described in detail as well as calibration and error-reduction methods. The major heating methods are described as well as the various considerations for emissive probe construction. Lastly, special considerations for electric propulsion plasmas are addressed, including high-energy densities, ion flows, magnetic fields, and potential fluctuations. Recommendations for probe design and operation are provided.

Cabin-fuselage-wing structural design concept with engine installation

NASA Technical Reports Server (NTRS)

Ariotti, Scott; Garner, M.; Cepeda, A.; Vieira, J.; Bolton, D.

1993-01-01

The purpose of this project is to provide a fuselage structural assembly and wing structural design that will be able to withstand the given operational parameters and loads provided by Federal Aviation Regulation Part 23 (FAR 23) and the Statement of Work (SOW). The goal is to provide a durable lightweight structure that will transfer the applied loads through the most efficient load path. Areas of producibility and maintainability of the structure will also be addressed. All of the structural members will also meet or exceed the desired loading criteria, along with providing adequate stiffness, reliability, and fatigue life as stated in the SOW. Considerations need to be made for control system routing and cabin heating/ventilation. The goal of the wing structure and carry through structure is also to provide a simple, lightweight structure that will transfer the aerodynamic forces produced by the wing, tailboom, and landing gear. These forces will be channeled through various internal structures sized for the pre-determined loading criteria. Other considerations were to include space for flaps, ailerons, fuel tanks, and electrical and control system routing. The difficulties encountered in the fuselage design include expanding the fuselage cabin to accept a third occupant in a staggered configuration and providing ample volume for their safety. By adding a third person the CG of aircraft will move forward so the engine needs to be moved aft to compensate for the difference in the moment. This required the provisions of a ring frame structure for the new position of the engine mount. The difficulties encountered in the wing structural design include resizing the wing for the increased capacity and weight, and compensating for a large torsion produced by the tail boom by placing a great number of stiffeners inside the boom, which will result in the relocation of the fuel tank. Finally, an adequate carry through structure for the wing and fuselage interface will be designed to effectively transmit loads through the fuselage.

Cryogenic Vacuum Insulation for Vessels and Piping

NASA Technical Reports Server (NTRS)

Kogan, A.; Fesmire, J.; Johnson, W.; Minnick, J.

2010-01-01

Cryogenic vacuum insulation systems, with proper materials selection and execution, can offer the highest levels of thermal performance. Three areas of consideration are vital to achieve the optimum result: materials, representative test conditions, and engineering approach for the particular application. Deficiency in one of these three areas can prevent optimum performance and lead to severe inefficiency. Materials of interest include micro-fiberglass, multilayer insulation, and composite arrangements. Cylindrical liquid nitrogen boil-off calorimetry methods were used. The need for standard thermal conductivity data is addressed through baseline testing. Engineering analysis and design factors such as layer thickness, density, and practicality are also considered.

Alternate fusion fuels workshop

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

Not Available

1981-06-01

The workshop was organized to focus on a specific confinement scheme: the tokamak. The workshop was divided into two parts: systems and physics. The topics discussed in the systems session were narrowly focused on systems and engineering considerations in the tokamak geometry. The workshop participants reviewed the status of system studies, trade-offs between d-t and d-d based reactors and engineering problems associated with the design of a high-temperature, high-field reactor utilizing advanced fuels. In the physics session issues were discussed dealing with high-beta stability, synchrotron losses and transport in alternate fuel systems. The agenda for the workshop is attached.

The Ulysses Reference Mission (URM); Proceedings of the EUROAVIA Design Workshop, Friedrichshafen, Federal Republic of Germany, Apr. 8-19, 1991

NASA Astrophysics Data System (ADS)

The present design symposium on the Ulysses Reference Mission (URM) provides data on the feasibility of the URM with particular attention given to reference data for Ulysses in the ecliptic plane as it passes the southern and northern pole areas of the sun. Specific issues addressed during the design workshop include the scientific objectives of the URM, the elements of the URM payload, the configuration and structural elements of the spacecraft, thermal control requirements and considerations, a system-engineering analysis, and the scientific subsystems of the URM. Also examined are the solar array and battery package, power control and distribution, technology considerations for the transmission of telemetric data, and a functional analysis of the URM on-board data-handling equipment. The description of the workshop concludes by noting that design studies are required to establish the moment of inertia and center of gravity of the URM spacecraft as well as specific mission parameters.

Theoretical Acoustic Absorber Design Approach for LOX/LCH4 Pintle Injector Rocket Engines

NASA Astrophysics Data System (ADS)

Candelaria, Jonathan

Liquid rocket engines, or LREs, have served a key role in space exploration efforts. One current effort involves the utilization of liquid oxygen (LOX) and liquid methane (LCH4) LREs to explore Mars with in-situ resource utilization for propellant production. This on-site production of propellant will allow for greater payload allocation instead of fuel to travel to the Mars surface, and refueling of propellants to travel back to Earth. More useable mass yields a greater benefit to cost ratio. The University of Texas at El Paso's (UTEP) Center for Space Exploration and Technology Research Center (cSETR) aims to further advance these methane propulsion systems with the development of two liquid methane - liquid oxygen propellant combination rocket engines. The design of rocket engines, specifically liquid rocket engines, is complex in that many variables are present that must be taken into consideration in the design. A problem that occurs in almost every rocket engine development program is combustion instability, or oscillatory combustion. It can result in the destruction of the rocket, subsequent destruction of the vehicle and compromise the mission. These combustion oscillations can vary in frequency from 100 to 20,000 Hz or more, with varying effects, and occur from different coupling phenomena. It is important to understand the effects of combustion instability, its physical manifestations, how to identify the instabilities, and how to mitigate or dampen them. Linear theory methods have been developed to provide a mathematical understanding of the low- to mid-range instabilities. Nonlinear theory is more complex and difficult to analyze mathematically, therefore no general analytical method that yields a solution exists. With limited resources, time, and the advice of our NASA mentors, a data driven experimental approach utilizing quarter wave acoustic dampener cavities was designed. This thesis outlines the methodology behind the design of an acoustic dampening system for a 500 lbf and a 2000 lbf throttleable liquid oxygen liquid methane pintle injector rocket engine.

Educational Encounters of the Third Kind.

PubMed

Génova, Gonzalo; González, M Rosario

2017-12-01

An engineer who becomes an educator in a school of software engineering has the mission to teach how to design and construct software systems, therein applying his or her knowledge and expertise. However, due to their engineering background, engineers may forget that educating a person is not the same as designing a machine, since a machine has a well-defined goal, whilst a person is capable to self-propose his or her own objectives. The ethical implications are clear: educating a free person must leave space for creativity and self-determination in his or her own discovery of the way towards personal and professional fulfillment, which cannot consist only in achieving goals selected by others. We present here an argument that is applicable to most fields of engineering. However, the dis-analogy between educating students and programming robots may have a particular appeal to software engineers and computer scientists. We think the consideration of three different stages in the educational process may be useful to engineers when they act as educators. We claim that the three stages (instructing, training and mentoring) are essential to engineering education. In particular, education is incomplete if the third stage is not reached. Moreover, mentoring (the third stage aimed at developing creativity and self-determination) is incompatible with an educational assessment framework that considers the goals of the engineer are always given by others. In our view, then, an integral education is not only beyond programming the behavior of students, but also beyond having them reach those given goals.

Space construction engineering - A new career field

NASA Technical Reports Server (NTRS)

Hagler, T.

1979-01-01

Opportunities for engineers in the design and construction of future large space structures are outlined. Possible space structures for the 1980's include a large mirror to reflect sunlight to earth for night lighting, an antenna for a personal communications system, a deep space communications relay system and a large passive radiometer to measure soil moisture. Considerations in the design of such structures include the lack of gravity, allowing structures to be built with much less supporting weight, the cost of transportation to orbit, leading to the use of aluminum or composite materials stored on reels and attached to a beam builder, and the required surface accuracy in the presence of thermal stresses. Construction factors to consider include the use of astronauts and remote manipulators in assembly, both of which have been demonstrated to be feasible.

Practical internal combustion engine laser spark plug development

NASA Astrophysics Data System (ADS)

Myers, Michael J.; Myers, John D.; Guo, Baoping; Yang, Chengxin; Hardy, Christopher R.

2007-09-01

Fundamental studies on laser ignition have been performed by the US Department of Energy under ARES (Advanced Reciprocating Engines Systems) and by the California Energy Commission under ARICE (Advanced Reciprocating Internal Combustion Engine). These and other works have reported considerable increases in fuel efficiencies along with substantial reductions in green-house gas emissions when employing laser spark ignition. Practical commercial applications of this technology require low cost high peak power lasers. The lasers must be small, rugged and able to provide stable laser beam output operation under adverse mechanical and environmental conditions. New DPSS (Diode Pumped Solid State) lasers appear to meet these requirements. In this work we provide an evaluation of HESP (High Efficiency Side Pumped) DPSS laser design and performance with regard to its application as a practical laser spark plug for use in internal combustion engines.

Power processing

NASA Technical Reports Server (NTRS)

Schwarz, F. C.

1971-01-01

Processing of electric power has been presented as a discipline that draws on almost every field of electrical engineering, including system and control theory, communications theory, electronic network design, and power component technology. The cost of power processing equipment, which often equals that of expensive, sophisticated, and unconventional sources of electrical energy, such as solar batteries, is a significant consideration in the choice of electric power systems.

Acquisition Environment, Safety, and Occupational Health: Lessons Learned From DoD Acquisition Systems Engineering Program Support Reviews

DTIC Science & Technology

2011-05-01

not integrated Lack of emphasis on implementing ESOH mitigations Failure to address USD (AT&L) hexavalent chrome policy 12 ODUSD(I&E) / CMRM Value of...4.1, Design Considerations Factor 4.1.4, ESOH Factor 4.1.7, Corrosion ( Hexavalent Chromium) 6 ODUSD(I&E) / CMRM 1. Mission Capabilities – Clarity and

Shielding Development for Nuclear Thermal Propulsion

NASA Technical Reports Server (NTRS)

Caffrey, Jarvis A.; Gomez, Carlos F.; Scharber, Luke L.

2015-01-01

Radiation shielding analysis and development for the Nuclear Cryogenic Propulsion Stage (NCPS) effort is currently in progress and preliminary results have enabled consideration for critical interfaces in the reactor and propulsion stage systems. Early analyses have highlighted a number of engineering constraints, challenges, and possible mitigating solutions. Performance constraints include permissible crew dose rates (shared with expected cosmic ray dose), radiation heating flux into cryogenic propellant, and material radiation damage in critical components. Design strategies in staging can serve to reduce radiation scatter and enhance the effectiveness of inherent shielding within the spacecraft while minimizing the required mass of shielding in the reactor system. Within the reactor system, shield design is further constrained by the need for active cooling with minimal radiation streaming through flow channels. Material selection and thermal design must maximize the reliability of the shield to survive the extreme environment through a long duration mission with multiple engine restarts. A discussion of these challenges and relevant design strategies are provided for the mitigation of radiation in nuclear thermal propulsion.

Engineering and fabrication cost considerations for cryogenic wind tunnel models

NASA Technical Reports Server (NTRS)

Boykin, R. M., Jr.; Davenport, J. B., Jr.

1983-01-01

Design and fabrication cost drivers for cryogenic transonic wind tunnel models are defined. The major cost factors for wind tunnel models are model complexity, tolerances, surface finishes, materials, material validation, and model inspection. The cryogenic temperatures require the use of materials with relatively high fracture toughness but at the same time high strength. Some of these materials are very difficult to machine, requiring extensive machine hours which can add significantly to the manufacturing costs. Some additional engineering costs are incurred to certify the materials through mechanical tests and nondestructive evaluation techniques, which are not normally required with conventional models. When instrumentation such as accelerometers and electronically scanned pressure modules is required, temperature control of these devices needs to be incorporated into the design, which requires added effort. Additional thermal analyses and subsystem tests may be necessary, which also adds to the design costs. The largest driver to the design costs is potentially the additional static and dynamic analyses required to insure structural integrity of the model and support system.

Future earth orbit transportation systems/technology implications

NASA Technical Reports Server (NTRS)

Henry, B. Z.; Decker, J. P.

1976-01-01

Assuming Space Shuttle technology to be state-of-the-art, projected technological advances to improve the capabilities of single-stage-to-orbit (SSTO) derivatives are examined. An increase of about 30% in payload performance can be expected from upgrading the present Shuttle system through weight and drag reductions and improvements in the propellants and engines. The ODINEX (Optimal Design Integration Executive Computer Program) program has been used to explore design options. An advanced technology SSTO baseline system derived from ODINEX analysis has a conventional wing-body configuration using LOX/LH engines, three with two-position nozzles with expansion ratios of 40 and 200 and four with fixed nozzles with an expansion ratio of 40. Two assisted-takeoff approaches are under consideration in addition to a concept in which the orbital vehicle takes off empty using airbreathing propulsion and carries out a rendezvous with two large cryogenic tankers carrying propellant at an altitude of 6100 m. Further approaches under examination for propulsion, aerothermodynamic design, and design integration are described.

The Robert E. Hopkins Center for Optical Design and Engineering

NASA Astrophysics Data System (ADS)

Zavislan, James M.; Brown, Thomas G.

2008-08-01

In 1929, a grant from Eastman Kodak and Bausch and Lomb established The Institute of Optics as the nation's first academic institution devoted to training optical scientists and engineers. The mission was 'to study light in all its phases', and the curriculum was designed to educate students in the fundamentals of optical science and build essential skills in applied optics and optical engineering. Indeed, our historic strength has been a balance between optical science and engineering--we have alumni who are carrying out prize-winning research in optical physics, alumni who are innovative optical engineers, and still other alumni who are leaders in the business community. Faculty who are top-notch optical engineers are an important resource to optical physics research groups -- likewise, teaching and modeling excellent optical science provides a strong underpinning for students on the applied/engineering end of the spectrum. This model -an undergraduate and graduate program that balances fundamental optics, applied optics, and optical engineering- has served us well. The impressive and diverse range of opportunities for our BS graduates has withstood economic cycles, and the students graduate with a healthy dose of practical experience. Undergraduate advisors, with considerable initiative from the program coordinator, are very aggressive in pointing students toward summer research and engineering opportunities. The vast majority of our undergraduate students graduate with at least one summer of experience in a company or a research laboratory. For example, 95% of the class of 2008 spent the summer of 2007 at companies and/or research laboratories: These include Zygo, NRL, Bausch and Lomb, The University of Rochester(The Institute of Optics, Medical Center, and Laboratory for Laser Energetics), QED, ARL Night Vision laboratories, JPL, Kollsman, OptiMax, Northrup Grumman, and at least two other companies. It is an impressive list, and bodes well for the career preparation for these students. While this extracurricular experience is truly world-class, an integrated design experience defined within our academic program is increasingly necessary for those going on to professional careers in engineering. This paper describes the philosophy behind a revision to our undergraduate curriculum that integrates a design experience and describes the engineering laboratory that has been established to make it a reality. The laboratory and design center has been named in honor of Robert E. Hopkins, former director and professor, co-founder of Tropel corporation, and a lifelong devotee to engineering innovation.

An integrated approach to engineering curricula improvement with multi-objective decision modeling and linear programming

NASA Astrophysics Data System (ADS)

Shea, John E.

The structure of engineering curricula currently in place at most colleges and universities has existed since the early 1950's, and reflects an historical emphasis on a solid foundation in math, science, and engineering science. However, there is often not a close match between elements of the traditional engineering education, and the skill sets that graduates need to possess for success in the industrial environment. Considerable progress has been made to restructure engineering courses and curricula. What is lacking, however, are tools and methodologies that incorporate the many dimensions of college courses, and how they are structured to form a curriculum. If curriculum changes are to be made, the first objective must be to determine what knowledge and skills engineering graduates need to possess. To accomplish this, a set of engineering competencies was developed from existing literature, and used in the development of a comprehensive mail survey of alumni, employers, students and faculty. Respondents proposed some changes to the topics in the curriculum and recommended that work to improve the curriculum be focused on communication, problem solving and people skills. The process of designing a curriculum is similar to engineering design, with requirements that must be met, and objectives that must be optimized. From this similarity came the idea for developing a linear, additive, multi-objective model that identifies the objectives that must be considered when designing a curriculum, and contains the mathematical relationships necessary to quantify the value of a specific alternative. The model incorporates the three primary objectives of engineering topics, skills, and curriculum design principles and uses data from the survey. It was used to design new courses, to evaluate various curricula alternatives, and to conduct sensitivity analysis to better understand their differences. Using the multi-objective model to identify the highest scoring curriculum from a catalog of courses is difficult because of the many factors being considered. To assist this process, the multi-objective model and the curriculum requirements were incorporated in a linear program to select the "optimum" curriculum. The application of this tool was also beneficial in identifying the active constraints that limit curriculum development and content.

Piloted simulation study of the effects of an automated trim system on flight characteristics of a light twin-engine airplane with one engine inoperative

NASA Technical Reports Server (NTRS)

Stewart, E. C.; Brown, P. W.; Yenni, K. R.

1986-01-01

A simulation study was conducted to investigate the piloting problems associated with failure of an engine on a generic light twin-engine airplane. A primary piloting problem for a light twin-engine airplane after an engine failure is maintaining precise control of the airplane in the presence of large steady control forces. To address this problem, a simulated automatic trim system which drives the trim tabs as an open-loop function of propeller slipstream measurements was developed. The simulated automatic trim system was found to greatly increase the controllability in asymmetric powered flight without having to resort to complex control laws or an irreversible control system. However, the trim-tab control rates needed to produce the dramatic increase in controllability may require special design consideration for automatic trim system failures. Limited measurements obtained in full-scale flight tests confirmed the fundamental validity of the proposed control law.

Microtube strip heat exchanger

NASA Astrophysics Data System (ADS)

Doty, F. D.

1991-10-01

This progress report is for the September-October 1991 quarter. We have demonstrated feasibility of higher specific conductance by a factor of five than any other work in high-temperature gas-to-gas exchangers. These laminar-flow, microtube exchangers exhibit extremely low pressure drop compared to alternative compact designs under similar conditions because of their much shorter flow length and larger total flow area for lower flow velocities. The design appears to be amenable to mass production techniques, but considerable process development remains. The reduction in materials usage and the improved heat exchanger performance promise to be of enormous significance in advanced engine designs and in cryogenics.

Trajectory Design Considerations for Exploration Mission 1

NASA Technical Reports Server (NTRS)

Dawn, Timothy F.; Gutkowski, Jeffrey P.; Batcha, Amelia L.

2017-01-01

Exploration Mission 1 (EM-1) will be the first mission to send an uncrewed Orion vehicle to cislunar space in 2018, targeted to a Distant Retrograde Orbit (DRO). Analysis of EM-1 DRO mission opportunities in 2018 help characterize mission parameters that are of interest to other subsystems (e.g., power, thermal, communications, flight operations, etc). Subsystems request mission design trades which include: landing lighting, addition of an Orion main engine checkout burn, and use of auxiliary thruster only cases. This paper examines the evolving trade studies that incorporate subsystem feedback and demonstrate the feasibility of these constrained mission trajectory designs and contingencies.

Micro-/nano-engineered cellular responses for soft tissue engineering and biomedical applications.

PubMed

Tay, Chor Yong; Irvine, Scott Alexander; Boey, Freddy Y C; Tan, Lay Poh; Venkatraman, Subbu

2011-05-23

The development of biomedical devices and reconstruction of functional ex vivo tissues often requires the need to fabricate biomimetic surfaces with features of sub-micrometer precision. This can be achieved with the advancements in micro-/nano-engineering techniques, allowing researchers to manipulate a plethora of cellular behaviors at the cell-biomaterial interface. Systematic studies conducted on these 2D engineered surfaces have unraveled numerous novel findings that can potentially be integrated as part of the design consideration for future 2D and 3D biomaterials and will no doubt greatly benefit tissue engineering. In this review, recent developments detailing the use of micro-/nano-engineering techniques to direct cellular orientation and function pertinent to soft tissue engineering will be highlighted. Particularly, this article aims to provide valuable insights into distinctive cell interactions and reactions to controlled surfaces, which can be exploited to understand the mechanisms of cell growth on micro-/nano-engineered interfaces, and to harness this knowledge to optimize the performance of 3D artificial soft tissue grafts and biomedical applications. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Katrina: macro-ethical issues for engineers.

PubMed

Newberry, Byron

2010-09-01

Hurricane Katrina was one of the worst disasters in United States history. Failures within New Orleans' engineered hurricane protection system (levees and floodwalls) contributed to the severity of the event and have drawn considerable public attention. In the time since Katrina, forensic investigations have uncovered a range of issues and problems related to the engineering work. In this article, my goal is to distill from these investigations, and the related literature that has accumulated, some overarching macro-ethical issues that are relevant for all engineers. I attempt to frame these issues, using illustrative examples taken from Katrina, in a way that might be of pedagogical use and benefit for engineering educators interested in engaging their students in discussions of engineering ethics, societal impact of engineered systems, engineering design, or related topics. Some of the issues discussed are problems of unanticipated failure modes, faulty assumptions, lack or misuse of information, the importance of resiliency, the effects of time, balancing competing interests, attending to the details of interfaces, the fickleness of risk perception, and how the past constrains the present.

Space Shuttle Main Engine - The Relentless Pursuit of Improvement

NASA Technical Reports Server (NTRS)

VanHooser, Katherine P.; Bradley, Douglas P.

2011-01-01

The Space Shuttle Main Engine (SSME) is the only reusable large liquid rocket engine ever developed. The specific impulse delivered by the staged combustion cycle, substantially higher than previous rocket engines, minimized volume and weight for the integrated vehicle. The dual pre-burner configuration permitted precise mixture ratio and thrust control while the fully redundant controller and avionics provided a very high degree of system reliability and health diagnosis. The main engine controller design was the first rocket engine application to incorporate digital processing. The engine was required to operate at a high chamber pressure to minimize engine volume and weight. Power level throttling was required to minimize structural loads on the vehicle early in flight and acceleration levels on the crew late in ascent. Fatigue capability, strength, ease of assembly and disassembly, inspectability, and materials compatibility were all major considerations in achieving a fully reusable design. During the multi-decade program the design evolved substantially using a series of block upgrades. A number of materials and manufacturing challenges were encountered throughout SSME s history. Significant development was required for the final configuration of the high pressure turbopumps. Fracture control was implemented to assess life limits of critical materials and components. Survival in the hydrogen environment required assessment of hydrogen embrittlement. Instrumentation systems were a challenge due to the harsh thermal and dynamic environments within the engine. Extensive inspection procedures were developed to assess the engine components between flights. The Space Shuttle Main Engine achieved a remarkable flight performance record. All flights were successful with only one mission requiring an ascent abort condition, which still resulted in an acceptable orbit and mission. This was achieved in large part via extensive ground testing to fully characterize performance and to establish acceptable life limits. During the program over a million seconds of accumulated test and flight time was achieved. Post flight inspection and assessment was a key part of assuring proper performance of the flight hardware. By the end of the program the predicted reliability had improved by a factor of four. These unique challenges, evolution of the design, and the resulting reliability will be discussed in this paper.

Culturally responsive engineering education: A case study of a pre-college introductory engineering course at Tibetan Children's Village School of Selakui

NASA Astrophysics Data System (ADS)

Santiago, Marisol Mercado

Culturally responsive teaching has been argued to be effective in the education of Indigenous youth. This approach emphasizes the legitimacy of a group's cultural heritage, helps to associate abstract academic knowledge with the group's sociocultural context, seeks to incorporate a variety of strategies to engage students who have different learning styles, and strives to integrate multicultural information in the educational contents, among other considerations. In this work, I explore the outcomes of a culturally responsive introductory engineering short course that I developed and taught to Tibetan students at Tibetan Children's Village of Selakui (in Uttarakhand, India). Based on my ethnographic research in Tibetan communities in northern India, I examine two research questions: (a) What are the processes to develop and implement a pre-college culturally responsive introductory engineering course? and (b) How do Tibetan culture and Buddhism influence the engineering design and teamwork of the pre-college Tibetan students who took the course? I designed then taught the course that featured elementary lectures on sustainability, introductory engineering design, energy alternatives, and manufacturing engineering. The course also included a pre-college engineering design project through which Tibetan high school students investigated a problem at the school and designed a possible solution to it. Drawing from postcolonial studies, engineering studies, engineering and social justice, Buddhist studies, and Tibetan studies, I provide an analysis of my findings. Based on my findings, I conclude that my culturally responsive approach of teaching was an effective method to help students feel that their cultural background was respected and included in a pre-college engineering course; however, some students felt resistance toward the teaching approach. In addition, the culturally relevant content that connected with their ways of living in their school, Tibetan communities, and surroundings helped the students to relate to abstract concepts in familiar settings. Lastly, they appreciated that I brought to the course relevant information about technology and society in India (their host country), engineers' work in industry, technologies used in other contexts as well, and projects that show how engineers can help to alleviate poverty. The findings of my research can inform (a) educators who are interested in integrating culturally responsive activities in their teaching methods, (b) researchers or teachers in ethnic minority schools abroad, (c) educators interested in developing engineering activities or courses for underrepresented ethnic minorities, ethnic diasporas or refugee youth in the United States, and (d) facilitators at multicultural engineering summer camps in the United States.

Airborne Laser Remote Sensor for Oil Detection and Classification : Engineering Requirements and Technical Considerations Relevant to a Performance Specification

DOT National Transportation Integrated Search

1975-08-01

This report outlines the engineering requirements for an Airborne Laser Remote Sensor for Oil Detection and Classification System. Detailed engineering requirements are given for the major units of the system. Technical considerations pertinent to a ...

Life prediction technologies for aeronautical propulsion systems

NASA Technical Reports Server (NTRS)

Mcgaw, Michael A.

1990-01-01

Fatigue and fracture problems continue to occur in aeronautical gas turbine engines. Components whose useful life is limited by these failure modes include turbine hot-section blades, vanes, and disks. Safety considerations dictate that catastrophic failures be avoided, while economic considerations dictate that catastrophic failures be avoided, while economic considerations dictate that noncatastrophic failures occur as infrequently as possible. Therefore, the decision in design is making the tradeoff between engine performance and durability. LeRC has contributed to the aeropropulsion industry in the area of life prediction technology for over 30 years, developing creep and fatigue life prediction methodologies for hot-section materials. At the present time, emphasis is being placed on the development of methods capable of handling both thermal and mechanical fatigue under severe environments. Recent accomplishments include the development of more accurate creep-fatigue life prediction methods such as the total strain version of LeRC's strain-range partitioning (SRP) and the HOST-developed cyclic damage accumulation (CDA) model. Other examples include the development of a more accurate cumulative fatigue damage rule - the double damage curve approach (DDCA), which provides greatly improved accuracy in comparison with usual cumulative fatigue design rules. Other accomplishments in the area of high-temperature fatigue crack growth may also be mentioned. Finally, we are looking to the future and are beginning to do research on the advanced methods which will be required for development of advanced materials and propulsion systems over the next 10-20 years.

Biomechanics and mechanobiology in functional tissue engineering

PubMed Central

Guilak, Farshid; Butler, David L.; Goldstein, Steven A.; Baaijens, Frank P.T.

2014-01-01

The field of tissue engineering continues to expand and mature, and several products are now in clinical use, with numerous other preclinical and clinical studies underway. However, specific challenges still remain in the repair or regeneration of tissues that serve a predominantly biomechanical function. Furthermore, it is now clear that mechanobiological interactions between cells and scaffolds can critically influence cell behavior, even in tissues and organs that do not serve an overt biomechanical role. Over the past decade, the field of “functional tissue engineering” has grown as a subfield of tissue engineering to address the challenges and questions on the role of biomechanics and mechanobiology in tissue engineering. Originally posed as a set of principles and guidelines for engineering of load-bearing tissues, functional tissue engineering has grown to encompass several related areas that have proven to have important implications for tissue repair and regeneration. These topics include measurement and modeling of the in vivo biomechanical environment; quantitative analysis of the mechanical properties of native tissues, scaffolds, and repair tissues; development of rationale criteria for the design and assessment of engineered tissues; investigation of the effects biomechanical factors on native and repair tissues, in vivo and in vitro; and development and application of computational models of tissue growth and remodeling. Here we further expand this paradigm and provide examples of the numerous advances in the field over the past decade. Consideration of these principles in the design process will hopefully improve the safety, efficacy, and overall success of engineered tissue replacements. PMID:24818797

A Novel Visual Interface to Foster Innovation in Mechanical Engineering and Protect from Patent Infringement

NASA Astrophysics Data System (ADS)

Sorce, Salvatore; Malizia, Alessio; Jiang, Pingfei; Atherton, Mark; Harrison, David

2018-04-01

One of the main time and money consuming tasks in the design of industrial devices and parts is the checking of possible patent infringements. Indeed, the great number of documents to be mined and the wide variety of technical language used to describe inventions are reasons why considerable amounts of time may be needed. On the other hand, the early detection of a possible patent conflict, in addition to reducing the risk of legal disputes, could stimulate a designers’ creativity to overcome similarities in overlapping patents. For this reason, there are a lot of existing patent analysis systems, each with its own features and access modes. We have designed a visual interface providing an intuitive access to such systems, freeing the designers from the specific knowledge of querying languages and providing them with visual clues. We tested the interface on a framework aimed at representing mechanical engineering patents; the framework is based on a semantic database and provides patent conflict analysis for early-stage designs. The interface supports a visual query composition to obtain a list of potentially overlapping designs.

Designing Extraterrestrial Plant Growth Habitats With Low Pressure Atmospheres

NASA Technical Reports Server (NTRS)

Corey, Kenneth A.

2001-01-01

In-situ resource utilization, provision of human life support requirements by bioregenerative methods, and engineering constraints for construction and deployment of plant growth structures on the surface of Mars all suggest the need for plant growth studies at hypobaric pressures. Past work demonstrated that plants will likely tolerate and grow at pressures at or below 10 kPa. Based upon this premise, concepts are developed for the design of reduced pressure atmospheres in lightweight, inflatable structures for plant growth systems on Mars with the goals of maximizing design simplicity and the use of local resources. A modular pod design is proposed as it could be integrated with large-scale production systems. Atmospheric modification of pod clusters would be based upon a pulse and scrub system using mass flow methods for atmospheric transport. A specific modification and control scenario is developed for a lettuce pod to illustrate the dynamics of carbon dioxide and oxygen exchange within a pod. Considerations of minimal atmospheric crop requirements will aid in the development of engineering designs and strategies for extraterrestrial plant growth structures that employ rarefied atmospheres.

Designing Extraterrestrial Plant Growth Habitats with Low Pressure Atmospheres

NASA Technical Reports Server (NTRS)

Corey, Kenneth A.

2002-01-01

In-situ resource utilization, provision of human life support requirements by bioregenerative methods, and engineering constraints for construction and deployment of plant growth structures on the surface of Mars all suggest the need for plant growth studies at hypobaric pressures. Past work demonstrated that plants will likely tolerate and grow at pressures at or below 10 kPa. Based upon this premise, concepts are developed for the design of reduced pressure atmospheres in lightweight, inflatable structures for plant growth systems on Mars with the goals of maximizing design simplicity and the use of local resources. A modular pod design is proposed as it could be integrated with large-scale production systems. Atmospheric modification of pod clusters would be based upon a pulse and scrub system using mass flow methods for atmospheric transport. A specific modification and control scenario is developed for a lettuce pod to illustrate the dynamics of carbon dioxide and oxygen exchange within a pod. Considerations of minimal atmospheric crop requirements will aid in the development of engineering designs and strategies for extraterrestrial plant growth structures that employ rarefied atmospheres.

Engineering specification and system design for CAD/CAM of custom shoes: UMC project effort

NASA Technical Reports Server (NTRS)

Bao, Han P.

1990-01-01

Further experimentations were made to improve the design and fabrication techniques of the integrated sole. The sole design is shown to be related to the foot position requirements and the actual shape of the foot including presence of neurotropic ulcers or other infections. Factors for consideration were: heel pitch, balance line, and rigidity conditions of the foot. Machining considerations were also part of the design problem. Among these considerations, widths of each contour, tool motion, tool feed rate, depths of cut, and slopes of cut at the boundary were the key elements. The essential fabrication techniques evolved around the idea of machining a mold then, using quick-firm latex material, casting the sole through the mold. Two main mold materials were experimented with: plaster and wood. Plaster was very easy to machine and shape but could barely support the pressure in the hydraulic press required by the casting process. Wood was found to be quite effective in terms of relative cost, strength, and surface smoothness except for the problem of cutting against the fibers which could generate ragged surfaces. The programming efforts to convert the original dBase programs into C programs so that they could be executed on the SUN Computer at North Carolina State University are discussed.

Technical Handbook for Facilities Engineering and Construction Manual, Part 2: Federally Assisted Activities. Guide for Project Applicants-Construction Management Services. Department Technical Handbook Series.

ERIC Educational Resources Information Center

Department of Health , Education, and Welfare, Washington., DC. Office of the Secretary.

This handbook provides a basis for consideration of acceptable approaches which are available and may be used to initiate the use of construction management services in the planning, design, and construction of federally assisted construction projects. It includes the mandatory federal requirements as well as acceptable procedures for selecting…

Usage of Parameterized Fatigue Spectra and Physics-Based Systems Engineering Models for Wind Turbine Component Sizing: Preprint

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

Parsons, Taylor; Guo, Yi; Veers, Paul

Software models that use design-level input variables and physics-based engineering analysis for estimating the mass and geometrical properties of components in large-scale machinery can be very useful for analyzing design trade-offs in complex systems. This study uses DriveSE, an OpenMDAO-based drivetrain model that uses stress and deflection criteria to size drivetrain components within a geared, upwind wind turbine. Because a full lifetime fatigue load spectrum can only be defined using computationally-expensive simulations in programs such as FAST, a parameterized fatigue loads spectrum that depends on wind conditions, rotor diameter, and turbine design life has been implemented. The parameterized fatigue spectrummore » is only used in this paper to demonstrate the proposed fatigue analysis approach. This paper details a three-part investigation of the parameterized approach and a comparison of the DriveSE model with and without fatigue analysis on the main shaft system. It compares loads from three turbines of varying size and determines if and when fatigue governs drivetrain sizing compared to extreme load-driven design. It also investigates the model's sensitivity to shaft material parameters. The intent of this paper is to demonstrate how fatigue considerations in addition to extreme loads can be brought into a system engineering optimization.« less

Implementation of object-oriented programming in study of electrical race car

NASA Astrophysics Data System (ADS)

Nowak, M.; Baier, M.

2016-08-01

The paper covers issue of conducting advanced research of electrical race car participating in international competition called Sileverline Corporate Challenge. Process of designing race cars in Silesian Greenpower team is aided by a professional engine test stand built particularly in purpose of this research. Phase of testing and simulation is an important part of the implementation of new technologies. Properly developed solutions and test procedures are able to significantly shorten development time and reduce design costs. Testing process must be controlled by a modular and flexible application, easy to modify and ensuring safety. This paper describes the concept of object-oriented programming in LabVIEW and exemplary architecture of object-oriented control application designed to control engine test stand of the electrical race car. Eventually, the task of application will be to steer the electromagnetic brake and the engine load torque to perform according to data from the actual race track. During the designing process of the car, minimizing energy losses and maximizing powertrain efficiency are the main aspects taken into consideration. One of the crucial issues to accomplish these goals is to maintain optimal performance of the motor by applying effective cooling. The paper covers the research verifying the effectiveness of the cooling system.

Final Report for Project 13-4791: New Mechanistic Models of Creep-Fatigue Crack Growth Interactions for Advanced High Temperature Reactor Components

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

Kruzic, Jamie J; Siegmund, Thomas; Tomar, Vikas

This project developed and validated a novel, multi-scale, mechanism-based model to quantitatively predict creep-fatigue crack growth and failure for Ni-based Alloy 617 at 800°C. Alloy 617 is a target material for intermediate heat exchangers in Generation IV very high temperature reactor designs, and it is envisioned that this model will aid in the design of safe, long lasting nuclear power plants. The technical effectiveness of the model was shown by demonstrating that experimentally observed crack growth rates can be predicted under both steady state and overload crack growth conditions. Feasibility was considered by incorporating our model into a commercially availablemore » finite element method code, ABAQUS, that is commonly used by design engineers. While the focus of the project was specifically on an alloy targeted for Generation IV nuclear reactors, the benefits to the public are expected to be wide reaching. Indeed, creep-fatigue failure is a design consideration for a wide range of high temperature mechanical systems that rely on Ni-based alloys, including industrial gas power turbines, advanced ultra-super critical steam turbines, and aerospace turbine engines. It is envisioned that this new model can be adapted to a wide range of engineering applications.« less

Human error and the search for blame

NASA Technical Reports Server (NTRS)

Denning, Peter J.

1989-01-01

Human error is a frequent topic in discussions about risks in using computer systems. A rational analysis of human error leads through the consideration of mistakes to standards that designers use to avoid mistakes that lead to known breakdowns. The irrational side, however, is more interesting. It conditions people to think that breakdowns are inherently wrong and that there is ultimately someone who is responsible. This leads to a search for someone to blame which diverts attention from: learning from the mistakes; seeing the limitations of current engineering methodology; and improving the discourse of design.

Scaling of induction-cell transverse impedance: effect on accelerator design

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

Ekdahl, Carl August

2016-08-09

The strength of the dangerous beam breakup (BBU) instability in linear induction accelerators (LIAs) is characterized by the transverse coupling impedance Z ⊥. This note addresses the dimensional scaling of Z ⊥, which is important when comparing new LIA designs to existing accelerators with known i BBU growth. Moreover, it is shown that the scaling of Z ⊥ with the accelerating gap size relates BBU growth directly to high-voltage engineering considerations. It is proposed to firmly establish this scaling though a series of AMOS calculations.

Low and medium heating value coal gas catalytic combustor characterization

NASA Technical Reports Server (NTRS)

Schwab, J. A.

1982-01-01

Catalytic combustion with both low and medium heating value coal gases obtained from an operating gasifier was demonstrated. A practical operating range for efficient operation was determined, and also to identify potential problem areas were identified for consideration during stationary gas turbine engine design. The test rig consists of fuel injectors, a fuel-air premixing section, a catalytic reactor with thermocouple instrumentation and a single point, water cooled sample probe. The test rig included inlet and outlet transition pieces and was designed for installation into an existing test loop.

Challenges in engineering large customized bone constructs.

PubMed

Forrestal, David P; Klein, Travis J; Woodruff, Maria A

2017-06-01

The ability to treat large tissue defects with customized, patient-specific scaffolds is one of the most exciting applications in the tissue engineering field. While an increasing number of modestly sized tissue engineering solutions are making the transition to clinical use, successfully scaling up to large scaffolds with customized geometry is proving to be a considerable challenge. Managing often conflicting requirements of cell placement, structural integrity, and a hydrodynamic environment supportive of cell culture throughout the entire thickness of the scaffold has driven the continued development of many techniques used in the production, culturing, and characterization of these scaffolds. This review explores a range of technologies and methods relevant to the design and manufacture of large, anatomically accurate tissue-engineered scaffolds with a focus on the interaction of manufactured scaffolds with the dynamic tissue culture fluid environment. Biotechnol. Bioeng. 2017;114: 1129-1139. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Transient Mathematical Modeling for Liquid Rocket Engine Systems: Methods, Capabilities, and Experience

NASA Technical Reports Server (NTRS)

Seymour, David C.; Martin, Michael A.; Nguyen, Huy H.; Greene, William D.

2005-01-01

The subject of mathematical modeling of the transient operation of liquid rocket engines is presented in overview form from the perspective of engineers working at the NASA Marshall Space Flight Center. The necessity of creating and utilizing accurate mathematical models as part of liquid rocket engine development process has become well established and is likely to increase in importance in the future. The issues of design considerations for transient operation, development testing, and failure scenario simulation are discussed. An overview of the derivation of the basic governing equations is presented along with a discussion of computational and numerical issues associated with the implementation of these equations in computer codes. Also, work in the field of generating usable fluid property tables is presented along with an overview of efforts to be undertaken in the future to improve the tools use for the mathematical modeling process.

Transient Mathematical Modeling for Liquid Rocket Engine Systems: Methods, Capabilities, and Experience

NASA Technical Reports Server (NTRS)

Martin, Michael A.; Nguyen, Huy H.; Greene, William D.; Seymout, David C.

2003-01-01

The subject of mathematical modeling of the transient operation of liquid rocket engines is presented in overview form from the perspective of engineers working at the NASA Marshall Space Flight Center. The necessity of creating and utilizing accurate mathematical models as part of liquid rocket engine development process has become well established and is likely to increase in importance in the future. The issues of design considerations for transient operation, development testing, and failure scenario simulation are discussed. An overview of the derivation of the basic governing equations is presented along with a discussion of computational and numerical issues associated with the implementation of these equations in computer codes. Also, work in the field of generating usable fluid property tables is presented along with an overview of efforts to be undertaken in the future to improve the tools use for the mathematical modeling process.

Thrust Augmentation of a Turbojet Engine at Simulated Flight Conditions by Introduction of a Water-Alcohol Mixture into the Compressor

NASA Technical Reports Server (NTRS)

Useller, James W.; Auble, Carmon M.; Harvey, Ray W., Sr.

1952-01-01

An investigation was conducted at simulated high-altitude flight conditions to evaluate the use of compressor evaporative cooling as a means of turbojet-engine thrust augmentation. Comparison of the performance of the engine with water-alcohol injection at the compressor inlet, at the sixth stage of the compressor, and at the sixth and ninth stages was made. From consideration of the thrust increases achieved, the interstage injection of the coolant was considered more desirable preferred over the combined sixth- and ninth-stage injection because of its relative simplicity. A maximum augmented net-thrust ratio of 1.106 and a maximum augmented jet-thrust ratio of 1.062 were obtained at an augmented liquid ratio of 2.98 and an engine-inlet temperature of 80 F. At lower inlet temperatures (-40 to 40 F), the maximum augmented net-thrust ratios ranged from 1.040 to 1.076 and the maximum augmented jet-thrust ratios ranged from 1.027 to 1.048, depending upon the inlet temperature. The relatively small increase in performance at the lower inlet-air temperatures can be partially attributed to the inadequate evaporation of the water-alcohol mixture, but the more significant limitation was believed to be caused by the negative influence of the liquid coolant on engine- component performance. In general, it is concluded that the effectiveness of the injection of a coolant into the compressor as a means of thrust augmentation is considerably influenced by the design characteristics of the components of the engine being used.

Generator voltage stabilisation for series-hybrid electric vehicles.

PubMed

Stewart, P; Gladwin, D; Stewart, J; Cowley, R

2008-04-01

This paper presents a controller for use in speed control of an internal combustion engine for series-hybrid electric vehicle applications. Particular reference is made to the stability of the rectified DC link voltage under load disturbance. In the system under consideration, the primary power source is a four-cylinder normally aspirated gasoline internal combustion engine, which is mechanically coupled to a three-phase permanent magnet AC generator. The generated AC voltage is subsequently rectified to supply a lead-acid battery, and permanent magnet traction motors via three-phase full bridge power electronic inverters. Two complementary performance objectives exist. Firstly to maintain the internal combustion engine at its optimal operating point, and secondly to supply a stable 42 V supply to the traction drive inverters. Achievement of these goals minimises the transient energy storage requirements at the DC link, with a consequent reduction in both weight and cost. These objectives imply constant velocity operation of the internal combustion engine under external load disturbances and changes in both operating conditions and vehicle speed set-points. An electronically operated throttle allows closed loop engine velocity control. System time delays and nonlinearities render closed loop control design extremely problematic. A model-based controller is designed and shown to be effective in controlling the DC link voltage, resulting in the well-conditioned operation of the hybrid vehicle.

Design Considerations For A Clinical XeC1 Excimer Laser Angioplasty System

NASA Astrophysics Data System (ADS)

Laudenslager, James B.; Goldenberg, Tsvi; Naghieh, Harry R.; Pham, Andrew A.; Narciso, Hugh L.; Tranis, Art; Pacala, Thomas J.

1989-09-01

Laser ablation and removal of intravascular plaque has long been a goal of physicians and physicists as an alternative treatment for coronary and peripheral artery disease. Early application of cw free light beam visible and infrared lasers such as argon ion or Nd:YAG lasers for this application were plagued by thermal side effects of the ablation process. Specifically, imprecise control of the boundary tissue injury produced by the deep penetration depth of the laser beam gave rise to early reclosure of the vessel due to the thermal nature of the ablation process. Pulsed ultraviolet laser free beam ablation of atherosclerotic plaque, however, does not produce thermal effects, cuts tissue precisely leaving a smooth wall and can ablate hard calcific lesions. We have chosen to develop a XeC1 excimer laser-fiberoptic delivery system for the clinical application of laser angioplasty based on achieving the desired therapeutic results for a laser revascularization procedure. Four major engineering design issues must be considered in order to produce a successful clinical laser angioplasty product. These engineering issues are: 1) Functional clinical engineering, 2) Regulatory design issues, 3) Hospital facility and user requirements, and 4) Economic issues for the manufacturer, the hospital and the patient.

Optical design and performance of F-Theta lenses for high-power and high-precision applications

NASA Astrophysics Data System (ADS)

Yurevich, V. I.; Grimm, V. A.; Afonyushkin, A. A.; Yudin, K. V.; Gorny, S. G.

2015-09-01

F-Theta lenses are widely used in remote laser processing. Nowadays, a large variety of scanning systems utilizing these devices are commercially available. In this paper, we demonstrate that all practical issues lose their triviality in designing high-performance F-Theta scanning systems. Laser power scaling requires attention to thermally-induced phenomena and ghost reflections. This requirement considerably complicates optimization of the optical configuration of the system and primary aberration correction, even during preliminary design. Obtaining high positioning accuracy requires taking into consideration all probable reasons for processing field distortion. We briefly describe the key engineering relationships and invariants as well as the typical design of a scanner lens and the main field-flattening techniques. Specific emphasis is directed to consideration of the fundamental nonlinearity of two-mirror scanners. To the best of our knowledge, this issue has not been yet studied. We also demonstrate the benefits of our F-Theta lens optimization technique, which uses a plurality of entrance pupils. The problems of eliminating focused ghost reflections and the effects of thermally-induced processes in high-power F-Theta lenses are considered. A set of multi-path 3D processing and laser cutting experiments were conducted and are presented herein to demonstrate the impact of laser beam degradation on the process performance. A selection of our non-standard optical designs is presented.

Biomechanics and mechanobiology in functional tissue engineering.

PubMed

Guilak, Farshid; Butler, David L; Goldstein, Steven A; Baaijens, Frank P T

2014-06-27

The field of tissue engineering continues to expand and mature, and several products are now in clinical use, with numerous other preclinical and clinical studies underway. However, specific challenges still remain in the repair or regeneration of tissues that serve a predominantly biomechanical function. Furthermore, it is now clear that mechanobiological interactions between cells and scaffolds can critically influence cell behavior, even in tissues and organs that do not serve an overt biomechanical role. Over the past decade, the field of "functional tissue engineering" has grown as a subfield of tissue engineering to address the challenges and questions on the role of biomechanics and mechanobiology in tissue engineering. Originally posed as a set of principles and guidelines for engineering of load-bearing tissues, functional tissue engineering has grown to encompass several related areas that have proven to have important implications for tissue repair and regeneration. These topics include measurement and modeling of the in vivo biomechanical environment; quantitative analysis of the mechanical properties of native tissues, scaffolds, and repair tissues; development of rationale criteria for the design and assessment of engineered tissues; investigation of the effects biomechanical factors on native and repair tissues, in vivo and in vitro; and development and application of computational models of tissue growth and remodeling. Here we further expand this paradigm and provide examples of the numerous advances in the field over the past decade. Consideration of these principles in the design process will hopefully improve the safety, efficacy, and overall success of engineered tissue replacements. Copyright © 2014 Elsevier Ltd. All rights reserved.

Multistate approaches in computational protein design

PubMed Central

Davey, James A; Chica, Roberto A

2012-01-01

Computational protein design (CPD) is a useful tool for protein engineers. It has been successfully applied towards the creation of proteins with increased thermostability, improved binding affinity, novel enzymatic activity, and altered ligand specificity. Traditionally, CPD calculations search and rank sequences using a single fixed protein backbone template in an approach referred to as single-state design (SSD). While SSD has enjoyed considerable success, certain design objectives require the explicit consideration of multiple conformational and/or chemical states. Cases where a “multistate” approach may be advantageous over the SSD approach include designing conformational changes into proteins, using native ensembles to mimic backbone flexibility, and designing ligand or oligomeric association specificities. These design objectives can be efficiently tackled using multistate design (MSD), an emerging methodology in CPD that considers any number of protein conformational or chemical states as inputs instead of a single protein backbone template, as in SSD. In this review article, recent examples of the successful design of a desired property into proteins using MSD are described. These studies employing MSD are divided into two categories—those that utilized multiple conformational states, and those that utilized multiple chemical states. In addition, the scoring of competing states during negative design is discussed as a current challenge for MSD. PMID:22811394

Rational engineering of physicochemical properties of nanomaterials for biomedical applications with nanotoxicological perspectives.

PubMed

Navya, P N; Daima, Hemant Kumar

2016-01-01

Innovative engineered nanomaterials are at the leading edge of rapidly emerging fields of nanobiotechnology and nanomedicine. Meticulous synthesis, unique physicochemical properties, manifestation of chemical or biological moieties on the surface of materials make engineered nanostructures suitable for a variety of biomedical applications. Besides, tailored nanomaterials exhibit entirely novel therapeutic applications with better functionality, sensitivity, efficiency and specificity due to their customized unique physicochemical and surface properties. Additionally, such designer made nanomaterials has potential to generate series of interactions with various biological entities including DNA, proteins, membranes, cells and organelles at nano-bio interface. These nano-bio interactions are driven by colloidal forces and predominantly depend on the dynamic physicochemical and surface properties of nanomaterials. Nevertheless, recent development and atomic scale tailoring of various physical, chemical and surface properties of nanomaterials is promising to dictate their interaction in anticipated manner with biological entities for biomedical applications. As a result, rationally designed nanomaterials are in extensive demand for bio-molecular detection and diagnostics, therapeutics, drug and gene delivery, fluorescent labelling, tissue engineering, biochemical sensing and other pharmaceuticals applications. However, toxicity and risk associated with engineered nanomaterials is rather unclear or not well understood; which is gaining considerable attention and the field of nanotoxicology is evolving promptly. Therefore, this review explores current knowledge of articulate engineering of nanomaterials for biomedical applications with special attention on potential toxicological perspectives.

Rational engineering of physicochemical properties of nanomaterials for biomedical applications with nanotoxicological perspectives

NASA Astrophysics Data System (ADS)

Navya, P. N.; Daima, Hemant Kumar

2016-02-01

Innovative engineered nanomaterials are at the leading edge of rapidly emerging fields of nanobiotechnology and nanomedicine. Meticulous synthesis, unique physicochemical properties, manifestation of chemical or biological moieties on the surface of materials make engineered nanostructures suitable for a variety of biomedical applications. Besides, tailored nanomaterials exhibit entirely novel therapeutic applications with better functionality, sensitivity, efficiency and specificity due to their customized unique physicochemical and surface properties. Additionally, such designer made nanomaterials has potential to generate series of interactions with various biological entities including DNA, proteins, membranes, cells and organelles at nano-bio interface. These nano-bio interactions are driven by colloidal forces and predominantly depend on the dynamic physicochemical and surface properties of nanomaterials. Nevertheless, recent development and atomic scale tailoring of various physical, chemical and surface properties of nanomaterials is promising to dictate their interaction in anticipated manner with biological entities for biomedical applications. As a result, rationally designed nanomaterials are in extensive demand for bio-molecular detection and diagnostics, therapeutics, drug and gene delivery, fluorescent labelling, tissue engineering, biochemical sensing and other pharmaceuticals applications. However, toxicity and risk associated with engineered nanomaterials is rather unclear or not well understood; which is gaining considerable attention and the field of nanotoxicology is evolving promptly. Therefore, this review explores current knowledge of articulate engineering of nanomaterials for biomedical applications with special attention on potential toxicological perspectives.

The Development of 2700-3000 F Environmental Barrier Coatings for SiC/SiC Ceramic Matrix Composites: Challenges and Opportunities

NASA Technical Reports Server (NTRS)

Zhu, Dongming

2015-01-01

Environmental barrier coatings (EBCs) and SiCSiC ceramic matrix composites (CMCs) systems will play a crucial role in future turbine engines for hot-section component applications because of their ability to significantly increase engine operating temperatures, reduce engine weight and cooling requirements. The development of prime-reliant environmental barrier coatings is a key to enable the applications of the envisioned 2700-3000F EBC - CMC systems to help achieve next generation engine performance and durability goals. This paper will primarily address the performance requirements and design considerations of environmental barrier coatings for turbine engine applications. The emphasis is placed on current NASA candidate environmental barrier coating systems for SiCSiC CMCs, their performance benefits and design limitations in long-term operation and combustion environments. The efforts have been also directed to developing prime-reliant, self-healing 2700F EBC bond coat; and high stability, lower thermal conductivity, and durable EBC top coats. Major technical barriers in developing environmental barrier coating systems, the coating integrations with next generation CMCs having the improved environmental stability, cyclic durability, erosion-impact resistance, and long-term system performance will be described. The research and development opportunities for turbine engine environmental barrier coating systems by utilizing improved compositions, state-of-the-art processing methods, and simulated environment testing and durability modeling will be discussed.

Stirling engines for low-temperature solar-thermal-electric power generation

NASA Astrophysics Data System (ADS)

der Minassians, Artin

This dissertation discusses the design and development of a distributed solar-thermal-electric power generation system that combines solar-thermal technology with a moderate-temperature Stirling engine to generate electricity. The conceived system incorporates low-cost materials and utilizes simple manufacturing processes. This technology is expected to achieve manufacturing cost of less than $1/W. Since solar-thermal technology is mature, the analysis, design, and experimental assessment of moderate-temperature Stirling engines is the main focus of this thesis. The design, fabrication, and test of a single-phase free-piston Stirling engine prototype is discussed. This low-power prototype is designed and fabricated as a test rig to provide a clear understanding of the Stirling cycle operation, to identify the key components and the major causes of irreversibility, and to verify corresponding theoretical models. As a component, the design of a very low-loss resonant displacer piston subsystem is discussed. The displacer piston is part of a magnetic circuit that provides both a required stiffness and actuation forces. The stillness is provided by a magnetic spring, which incorporates an array of permanent magnets and has a very linear stiffness characteristic that facilitates the frequency tuning. In this prototype, the power piston is not mechanically linked to the displacer piston and forms a mass-spring resonating subsystem with the engine chamber gas spring and has resonant frequency matched to that of the displacer. The fabricated engine prototype is successfully tested and the experimental results are presented and discussed. Extensive experimentation on individual component subsystems confirms the theoretical models and design considerations, providing a sound basis for higher power Stirling engine designs for residential or commercial deployments. Multi-phase Stirling engine systems are also considered and analyzed. The modal analysis of these machines proves their self-starting potential. The start-up temperature, i.e., the heater temperature at which the system starts its operation, is derived based on the same modal analysis. Following the mathematical modeling, the design, fabrication, and test of a symmetric three-phase free-piston Stirling engine system are discussed. The system is designed to operate with moderate-temperature heat input that is consistent with solar-thermal collectors. Diaphragm pistons and nylon flexures are considered for this prototype to eliminate surface friction and provide appropriate seals. The experimental results are presented and compared with design calculations. Experimental assessments confirm the models for flow friction and gas spring hysteresis dissipation. It is revealed that gas spring hysteresis loss is an important dissipation phenomenon in low-power low-pressure Stirling engines, and should be carefully addressed during the design as it may hinder the engine operation. Further analysis shows that the gas hysteresis dissipation can be reduced drastically by increasing the number of phases in a system with a little compromise on the operating frequency and, hence, the output power. It is further shown that for an even number of phases, half of the pistons could be eliminated by utilizing a reverser. By introducing a reverser to the fabricated system, the system proves its self-starting capability in engine mode and validates the derived expressions for computing the start-up temperature.

Advanced Low Conductivity Thermal Barrier Coatings: Performance and Future Directions (Invited paper)

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Miller, Robert A.

2008-01-01

Thermal barrier coatings will be more aggressively designed to protect gas turbine engine hot-section components in order to meet future engine higher fuel efficiency and lower emission goals. In this presentation, thermal barrier coating development considerations and performance will be emphasized. Advanced thermal barrier coatings have been developed using a multi-component defect clustering approach, and shown to have improved thermal stability and lower conductivity. The coating systems have been demonstrated for high temperature combustor applications. For thermal barrier coatings designed for turbine airfoil applications, further improved erosion and impact resistance are crucial for engine performance and durability. Erosion resistant thermal barrier coatings are being developed, with a current emphasis on the toughness improvements using a combined rare earth- and transition metal-oxide doping approach. The performance of the toughened thermal barrier coatings has been evaluated in burner rig and laser heat-flux rig simulated engine erosion and thermal gradient environments. The results have shown that the coating composition optimizations can effectively improve the erosion and impact resistance of the coating systems, while maintaining low thermal conductivity and cyclic durability. The erosion, impact and high heat-flux damage mechanisms of the thermal barrier coatings will also be described.

Advanced Low Conductivity Thermal Barrier Coatings: Performance and Future Directions

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Miller, Robert A.

2008-01-01

Thermal barrier coatings will be more aggressively designed to protect gas turbine engine hot-section components in order to meet future engine higher fuel efficiency and lower emission goals. In this presentation, thermal barrier coating development considerations and performance will be emphasized. Advanced thermal barrier coatings have been developed using a multi-component defect clustering approach, and shown to have improved thermal stability and lower conductivity. The coating systems have been demonstrated for high temperature combustor applications. For thermal barrier coatings designed for turbine airfoil applications, further improved erosion and impact resistance are crucial for engine performance and durability. Erosion resistant thermal barrier coatings are being developed, with a current emphasis on the toughness improvements using a combined rare earth- and transition metal-oxide doping approach. The performance of the toughened thermal barrier coatings has been evaluated in burner rig and laser heat-flux rig simulated engine erosion and thermal gradient environments. The results have shown that the coating composition optimizations can effectively improve the erosion and impact resistance of the coating systems, while maintaining low thermal conductivity and cyclic durability. The erosion, impact and high heat-flux damage mechanisms of the thermal barrier coatings will also be described.

Crew Launch Vehicle (CLV) Upper Stage Configuration Selection Process

NASA Technical Reports Server (NTRS)

Davis, Daniel J.; Coook, Jerry R.

2006-01-01

The Crew Launch Vehicle (CLV), a key component of NASA's blueprint for the next generation of spacecraft to take humans back to the moon, is being designed and built by engineers at NASA s Marshall Space Flight Center (MSFC). The vehicle s design is based on the results of NASA's 2005 Exploration Systems Architecture Study (ESAS), which called for development of a crew-launch system to reduce the gap between Shuttle retirement and Crew Exploration Vehicle (CEV) Initial Operating Capability, identification of key technologies required to enable and significantly enhance these reference exploration systems, and a reprioritization of near- and far-term technology investments. The Upper Stage Element (USE) of the CLV is a clean-sheet approach that is being designed and developed in-house, with element management at MSFC. The USE concept is a self-supporting cylindrical structure, approximately 115' long and 216" in diameter, consisting of the following subsystems: Primary Structures (LOX Tank, LH2 Tank, Intertank, Thrust Structure, Spacecraft Payload Adaptor, Interstage, Forward and Aft Skirts), Secondary Structures (Systems Tunnel), Avionics and Software, Main Propulsion System, Reaction Control System, Thrust Vector Control, Auxiliary Power Unit, and Hydraulic Systems. The ESAS originally recommended a CEV to be launched atop a four-segment Space Shuttle Main Engine (SSME) CLV, utilizing an RS-25 engine-powered upper stage. However, Agency decisions to utilize fewer CLV development steps to lunar missions, reduce the overall risk for the lunar program, and provide a more balanced engine production rate requirement prompted engineers to switch to a five-segment design with a single Saturn-derived J-2X engine. This approach provides for single upper stage engine development for the CLV and an Earth Departure Stage, single Reusable Solid Rocket Booster (RSRB) development for the CLV and a Cargo Launch Vehicle, and single core SSME development. While the RSRB design has changed since the CLV Project's inception, the USE design has remained essentially a clean-sheet approach. Although a clean-sheet upper stage design inherently carries more risk than a modified design, it does offer many advantages: a design for increased reliability; built-in extensibility to allow for commonality/growth without major redesign; and incorporation of state-of-the-art materials, hardware, and design, fabrication, and test techniques and processes to facilitate a potentially better, more reliable system. Because consideration was given in the ESAS to both clean-sheet and modified USE designs, this paper will highlight the advantages and disadvantages of both approaches and provide a detailed discussion of trades/selections made that led to the final upper stage configuration.

Object-oriented approach for gas turbine engine simulation

NASA Technical Reports Server (NTRS)

Curlett, Brian P.; Felder, James L.

1995-01-01

An object-oriented gas turbine engine simulation program was developed. This program is a prototype for a more complete, commercial grade engine performance program now being proposed as part of the Numerical Propulsion System Simulator (NPSS). This report discusses architectural issues of this complex software system and the lessons learned from developing the prototype code. The prototype code is a fully functional, general purpose engine simulation program, however, only the component models necessary to model a transient compressor test rig have been written. The production system will be capable of steady state and transient modeling of almost any turbine engine configuration. Chief among the architectural considerations for this code was the framework in which the various software modules will interact. These modules include the equation solver, simulation code, data model, event handler, and user interface. Also documented in this report is the component based design of the simulation module and the inter-component communication paradigm. Object class hierarchies for some of the code modules are given.

Parametric sensitivity study for solar-assisted heat-pump systems

NASA Astrophysics Data System (ADS)

White, N. M.; Morehouse, J. H.

1981-07-01

The engineering and economic parameters affecting life-cycle costs for solar-assisted heat pump systems are investigted. The change in energy usage resulting from each engineering parameter varied was developed from computer simulations, and is compared with results from a stand-alone heat pump system. Three geographical locations are considered: Washington, DC, Fort Worth, TX, and Madison, WI. Results indicate that most engineering changes to the systems studied do not provide significant energy savings. The most promising parameters to ary are the solar collector parameters tau (-) and U/sub L/ the heat pump capacity at design point, and the minimum utilizable evaporator temperature. Costs associated with each change are estimated, and life-cycle costs computed for both engineering parameters and economic variations in interest rate, discount rate, tax credits, fuel unit costs and fuel inflation rates. Results indicate that none of the feasibile engineering changes for the system configuration studied will make these systems economically competitive with the stand-alone heat pump without a considerable tax credit.

Metals production

NASA Technical Reports Server (NTRS)

Beck, Theodore S.

1992-01-01

Existing procedures for design of electrochemical plants can be used for design of lunar processes taking into consideration the differences in environmental conditions. These differences include: 1/6 Earth gravity, high vacuum, solar electrical and heat source, space radiation heat sink, long days and nights, and different availability and economics of materials, energy, and labor. Techniques have already been developed for operation of relatively small scale hydrogen-oxygen fuel cell systems used in the U.S. lunar landing program. Design and operation of lunar aqueous electrolytic process plants appears to be within the state-of-the-art. Finding or developing compatible materials for construction and designing of fused-magma metal winning cells will present a real engineering challenge.

Advanced Fusion Reactors for Space Propulsion and Power Systems

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

Chapman, John J.

In recent years the methodology proposed for conversion of light elements into energy via fusion has made steady progress. Scientific studies and engineering efforts in advanced fusion systems designs have introduced some new concepts with unique aspects including consideration of Aneutronic fuels. The plant parameters for harnessing aneutronic fusion appear more exigent than those required for the conventional fusion fuel cycle. However aneutronic fusion propulsion plants for Space deployment will ultimately offer the possibility of enhanced performance from nuclear gain as compared to existing ionic engines as well as providing a clean solution to Planetary Protection considerations and requirements. Protonmore » triggered 11Boron fuel (p- 11B) will produce abundant ion kinetic energy for In-Space vectored thrust. Thus energetic alpha particles' exhaust momentum can be used directly to produce high Isp thrust and also offer possibility of power conversion into electricity. p-11B is an advanced fusion plant fuel with well understood reaction kinematics but will require some new conceptual thinking as to the most effective implementation.« less

Advanced Fusion Reactors for Space Propulsion and Power Systems

NASA Technical Reports Server (NTRS)

Chapman, John J.

2011-01-01

In recent years the methodology proposed for conversion of light elements into energy via fusion has made steady progress. Scientific studies and engineering efforts in advanced fusion systems designs have introduced some new concepts with unique aspects including consideration of Aneutronic fuels. The plant parameters for harnessing aneutronic fusion appear more exigent than those required for the conventional fusion fuel cycle. However aneutronic fusion propulsion plants for Space deployment will ultimately offer the possibility of enhanced performance from nuclear gain as compared to existing ionic engines as well as providing a clean solution to Planetary Protection considerations and requirements. Proton triggered 11Boron fuel (p- 11B) will produce abundant ion kinetic energy for In-Space vectored thrust. Thus energetic alpha particles "exhaust" momentum can be used directly to produce high ISP thrust and also offer possibility of power conversion into electricity. p- 11B is an advanced fusion plant fuel with well understood reaction kinematics but will require some new conceptual thinking as to the most effective implementation.

Application of modern tools and techniques to maximize engineering productivity in the development of orbital operations plans for the space station progrm

NASA Technical Reports Server (NTRS)

Manford, J. S.; Bennett, G. R.

1985-01-01

The Space Station Program will incorporate analysis of operations constraints and considerations in the early design phases to avoid the need for later modifications to the Space Station for operations. The application of modern tools and administrative techniques to minimize the cost of performing effective orbital operations planning and design analysis in the preliminary design phase of the Space Station Program is discussed. Tools and techniques discussed include: approach for rigorous analysis of operations functions, use of the resources of a large computer network, and providing for efficient research and access to information.

Lubricant effects on bearing life

NASA Technical Reports Server (NTRS)

Zaretsky, Erwin V.

1986-01-01

Lubricant considerations for rolling-element bearings have within the last two decades taken on added importance in the design and operation of mechanical systems. The phenomenon which limits the useful life of bearings is rolling-element or surface pitting fatigue. The elastohydrodynamic (EHD) film thickness which separates the ball or roller surface from those of the raceways of the bearing directly affects bearing life. Chemical additives added to the lubricant can also significantly affect bearings life and reliability. The interaction of these physical and chemical effects is important to the design engineer and user of these systems. Design methods and lubricant selection for rolling-element bearings are presented and discussed.

NGDS User Centered Design Meeting the Needs of the Geothermal Community

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

Boyd, Suzanne; Zheng, Sam; Patten, Kim

2013-10-15

In order to ensure the widest and greatest utility of IT and software projects designed for geothermal reservoir engineer- ing the full consideration of end users’ task and workflow needs must be evaluated. This paper describes the user-centered design (UCD) approach taken in the development of a user interface (UI) solution for the National Geothermal Data System (NGDS). This development process has been research based, highly collabora- tive, and incorporates state-of-the-art practices to ensure a quality user experience. Work is continuing on the interface, including future usability tests to further refine the interfaces as the overall system is developed.

NGDS USER CENTERED DESIGN MEETING THE NEEDS OF THE GEOTHERMAL COMMUNITY

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

Boyd, Suzanne; Zheng, Sam Xianjun; Patten, Kim

In order to ensure the widest and greatest utility of IT and software projects designed for geothermal reservoir engineering the full consideration of end users’ task and workflow needs must be evaluated. This paper describes the user-centered design (UCD) approach taken in the development of a user interface (UI) solution for the National Geothermal Data System (NGDS). This development process has been researched based, highly collaborative, and incorporates state-of-the-art practices to ensure a quality user experience. Work is continuing on the interface, including future usability tests to further refine the interfaces as the overall system is developed.

Design Considerations for Developing Biodegradable Magnesium Implants

NASA Astrophysics Data System (ADS)

Brar, Harpreet S.; Keselowsky, Benjamin G.; Sarntinoranont, Malisa; Manuel, Michele V.

The integration of biodegradable and bioabsorbable magnesium implants into the human body is a complex undertaking that faces major challenges. The complexity arises from the fact that biomaterials must meet both engineering and physiological requirements to ensure the desired properties. Historically, efforts have been focused on the behavior of commercial magnesium alloys in biological environments and their resultant effect on cell-mediated processes. Developing causal relationships between alloy chemistry and micro structure, and its effect on cellular behavior can be a difficult and time intensive process. A systems design approach driven by thermodynamics has the power to provide significant contributions in developing the next generation of magnesium alloy implants with controlled degradability, biocompatibility, and optimized mechanical properties, at reduced time and cost. This approach couples experimental research with theory and mechanistic modeling for the accelerated development of materials. The aim of this article is to enumerate this strategy, design considerations and hurdles for developing new magnesium alloys for use as biodegradable implant materials [1].

Error begat error: design error analysis and prevention in social infrastructure projects.

PubMed

Love, Peter E D; Lopez, Robert; Edwards, David J; Goh, Yang M

2012-09-01

Design errors contribute significantly to cost and schedule growth in social infrastructure projects and to engineering failures, which can result in accidents and loss of life. Despite considerable research that has addressed their error causation in construction projects they still remain prevalent. This paper identifies the underlying conditions that contribute to design errors in social infrastructure projects (e.g. hospitals, education, law and order type buildings). A systemic model of error causation is propagated and subsequently used to develop a learning framework for design error prevention. The research suggests that a multitude of strategies should be adopted in congruence to prevent design errors from occurring and so ensure that safety and project performance are ameliorated. Copyright © 2011. Published by Elsevier Ltd.

Biomolecular engineering for nanobio/bionanotechnology

NASA Astrophysics Data System (ADS)

Nagamune, Teruyuki

2017-04-01

Biomolecular engineering can be used to purposefully manipulate biomolecules, such as peptides, proteins, nucleic acids and lipids, within the framework of the relations among their structures, functions and properties, as well as their applicability to such areas as developing novel biomaterials, biosensing, bioimaging, and clinical diagnostics and therapeutics. Nanotechnology can also be used to design and tune the sizes, shapes, properties and functionality of nanomaterials. As such, there are considerable overlaps between nanotechnology and biomolecular engineering, in that both are concerned with the structure and behavior of materials on the nanometer scale or smaller. Therefore, in combination with nanotechnology, biomolecular engineering is expected to open up new fields of nanobio/bionanotechnology and to contribute to the development of novel nanobiomaterials, nanobiodevices and nanobiosystems. This review highlights recent studies using engineered biological molecules (e.g., oligonucleotides, peptides, proteins, enzymes, polysaccharides, lipids, biological cofactors and ligands) combined with functional nanomaterials in nanobio/bionanotechnology applications, including therapeutics, diagnostics, biosensing, bioanalysis and biocatalysts. Furthermore, this review focuses on five areas of recent advances in biomolecular engineering: (a) nucleic acid engineering, (b) gene engineering, (c) protein engineering, (d) chemical and enzymatic conjugation technologies, and (e) linker engineering. Precisely engineered nanobiomaterials, nanobiodevices and nanobiosystems are anticipated to emerge as next-generation platforms for bioelectronics, biosensors, biocatalysts, molecular imaging modalities, biological actuators, and biomedical applications.

A Study of Ballast Water Treatment Using Engine Waste Heat

NASA Astrophysics Data System (ADS)

Balaji, Rajoo; Yaakob, Omar; Koh, Kho King; Adnan, Faizul Amri bin; Ismail, Nasrudin bin; Ahmad, Badruzzaman bin; Ismail, Mohd Arif bin

2018-05-01

Heat treatment of ballast water using engine waste heat can be an advantageous option complementing any proven technology. A treatment system was envisaged based on the ballast system of an existing, operational crude carrier. It was found that the available waste heat could raise the temperatures by 25 °C and voyage time requirements were found to be considerable between 7 and 12 days to heat the high volumes of ballast water. Further, a heat recovery of 14-33% of input energies from exhaust gases was recorded while using a test rig arrangement representing a shipboard arrangement. With laboratory level tests at temperature ranges of around 55-75 °C, almost complete species mortalities for representative phytoplankton, zooplankton and bacteria were observed while the time for exposure varied from 15 to 60 s. Based on the heat availability analyses for harvesting heat from the engine exhaust gases(vessel and test rig), heat exchanger designs were developed and optimized using Lagrangian method applying Bell-Delaware approaches. Heat exchanger designs were developed to suit test rig engines also. Based on these designs, heat exchanger and other equipment were procured and erected. The species' mortalities were tested in this mini-scale arrangement resembling the shipboard arrangement. The mortalities realized were > 95% with heat from jacket fresh water and exhaust gases alone. The viability of the system was thus validated.

Onsite biological treatment of an industrial landfill leachate: Microbiological and engineering considerations

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

Skladany, G.J.

Successful biological treatment of ground waters, leachates, or industrial process waters requires the combined action of basic microbiological processes with sound process engineering designs. Such a treatment system is then able to both efficiently and cost-effectively remediate the contaminants present. In this case study, laboratory treatability studies were initially used to demonstrate that toluic acids present in an industrial landfill leachate were amenable to biological treatment. A continuous flow submerged fixed-film bioreactor was then chosen as the optimal equipment design for use at the site. The system was designed to treat a leachate flow of 800 to 2,000 gallons permore » day (gpd) containing total isomeric toluic acid concentrations of 300 to 400 parts per million (ppm). The treatment equipment has been in continuous operation since July 1987. During this period, the total influent isomertic toluic acid concentration has decreased to approximately 45 ppm, and specific effluent toluic acid concentrations have remained below the 0.5 ppm detection limit.« less

AP1000{sup R} severe accident features and post-Fukushima considerations

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

Scobel, J. H.; Schulz, T. L.; Williams, M. G.

2012-07-01

The AP1000{sup R} passive nuclear power plant is uniquely equipped to withstand an extended station blackout scenario such as the events following the earthquake and tsunami at Fukushima without compromising core and containment integrity. The AP1000 plant shuts down the reactor, cools the core, containment and spent fuel pool for more than 3 days using passive systems that do not require AC or DC power or operator actions. Following this passive coping period, minimal operator actions are needed to extend the operation of the passive features to 7 days using installed equipment. To provide defense-in-depth for design extension conditions, themore » AP1000 plant has engineered features that mitigate the effects of core damage. Engineered features retain damaged core debris within the reactor vessel as a key feature. Other aspects of the design protect containment integrity during severe accidents, including unique features of the AP1000 design relative to passive containment cooling with water and air, and hydrogen management. (authors)« less

Fundamental rocket injector/spray programs at the Phillips Laboratory

NASA Astrophysics Data System (ADS)

Talley, D. G.

1993-11-01

The performance and stability of liquid rocket engines is determined to a large degree by atomization, mixing, and combustion processes. Control over these processes is exerted through the design of the injector. Injectors in liquid rocket engines are called upon to perform many functions. They must first of all mix the propellants to provide suitable performance in the shortest possible length. For main injectors, this is driven by the tradeoff between the combustion chamber performance, stability, efficiency, and its weight and cost. In gas generators and preburners, however, it is also driven by the possibility of damage to downstream components, for example piping and turbine blades. This can occur if unburned fuel and oxidant later react to create hot spots. Weight and cost considerations require that the injector design be simple and lightweight. For reusable engines, the injectors must also be durable and easily maintained. Suitable atomization and mixing must be produced with as small a pressure drop as possible, so that the size and weight of pressure vessels and turbomachinery can be minimized. However, the pressure drop must not be so small as to promote feed system coupled instabilities. Another important function of the injectors is to ensure that the injector face plate and the chamber and nozzle walls are not damaged. Typically this requires reducing the heat transfer to an acceptable level and also keeping unburned oxygen from chemically attacking the walls, particularly in reusable engines. Therefore the mixing distribution is often tailored to be fuel-rich near the walls. Wall heat transfer can become catastrophically damaging in the presence of acoustic instabilities, so the injector must prevent these from occurring at all costs. In addition to acoustic stability (but coupled with it), injectors must also be kinetically stable. That is, the flame itself must maintain ignition in the combustion chamber. This is not typically a problem with main injectors, but can be a consideration in preburners, where the desire to keep turbine inlet temperatures as cool as possible can make it advantageous for the preburners to operate as far from stoichiometry as can be tolerated.

77 FR 36341 - Control of Air Pollution From Aircraft and Aircraft Engines; Emission Standards and Test Procedures

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-18

...EPA is adopting several new aircraft engine emission standards for oxides of nitrogen (NOX), compliance flexibilities, and other regulatory requirements for aircraft turbofan or turbojet engines with rated thrusts greater than 26.7 kilonewtons (kN). We also are adopting certain other requirements for gas turbine engines that are subject to exhaust emission standards as follows. First, we are clarifying when the emission characteristics of a new turbofan or turbojet engine model have become different enough from its existing parent engine design that it must conform to the most current emission standards. Second, we are establishing a new reporting requirement for manufacturers of gas turbine engines that are subject to any exhaust emission standard to provide us with timely and consistent emission- related information. Third, and finally, we are establishing amendments to aircraft engine test and emissions measurement procedures. EPA actively participated in the United Nations' International Civil Aviation Organization (ICAO) proceedings in which most of these requirements were first developed. These regulatory requirements have largely been adopted or are actively under consideration by its member states. By adopting such similar standards, therefore, the United States maintains consistency with these international efforts.

Chief Joseph Dam, Columbia River, Washington, Community Impact Reports,

DTIC Science & Technology

1980-05-01

provide a major source of employment. Forested areas in the north and east pro- vide raw materials for an active lumber and wood products industry...Sewage Disposal Systems. The District Engineer of the Washington State Department of Ecology furnished the design flow capacity and its population...latter is without consideration of Chief Joseph Dam contruction impact. The high school is rated 1. 4.03 The individual residents are responsible for

Study of solid rocket motors for a space shuttle booster. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

Vonderesch, A. H.

1972-01-01

The factors affecting the choice of the 156 inch diameter, parallel burn, solid propellant rocket engine for use with the space shuttle booster are presented. Primary considerations leading to the selection are: (1) low booster vehicle cost, (2) the largest proven transportable system, (3) a demonstrated design, (4) recovery/reuse is feasible, (5) abort can be easily accomplished, and (6) ecological effects are minor.

Optically powered and interrogated rotary position sensor for aircraft engine control applications

NASA Astrophysics Data System (ADS)

Spillman, W. B.; Crowne, D. H.; Woodward, D. W.

A throttle level angle (TLA) sensing system is described that utilizes a capacitance based rotary position transducer that is powered and interrogated via light from a single multimode optical fiber. The system incorporates a unique GaAs device that serves as both a power converter and optical data transmitter. Design considerations are discussed, and the fabrication and performance of the sensor system are detailed.

Physics of Artificial Gravity

NASA Technical Reports Server (NTRS)

Bukley, Angie; Paloski, William; Clement, Gilles

2006-01-01

This chapter discusses potential technologies for achieving artificial gravity in a space vehicle. We begin with a series of definitions and a general description of the rotational dynamics behind the forces ultimately exerted on the human body during centrifugation, such as gravity level, gravity gradient, and Coriolis force. Human factors considerations and comfort limits associated with a rotating environment are then discussed. Finally, engineering options for designing space vehicles with artificial gravity are presented.

A framework for sustainable nanomaterial selection and design based on performance, hazard, and economic considerations.

PubMed

Falinski, Mark M; Plata, Desiree L; Chopra, Shauhrat S; Theis, Thomas L; Gilbertson, Leanne M; Zimmerman, Julie B

2018-04-30

Engineered nanomaterials (ENMs) and ENM-enabled products have emerged as potentially high-performance replacements to conventional materials and chemicals. As such, there is an urgent need to incorporate environmental and human health objectives into ENM selection and design processes. Here, an adapted framework based on the Ashby material selection strategy is presented as an enhanced selection and design process, which includes functional performance as well as environmental and human health considerations. The utility of this framework is demonstrated through two case studies, the design and selection of antimicrobial substances and conductive polymers, including ENMs, ENM-enabled products and their alternatives. Further, these case studies consider both the comparative efficacy and impacts at two scales: (i) a broad scale, where chemical/material classes are readily compared for primary decision-making, and (ii) within a chemical/material class, where physicochemical properties are manipulated to tailor the desired performance and environmental impact profile. Development and implementation of this framework can inform decision-making for the implementation of ENMs to facilitate promising applications and prevent unintended consequences.

Approximation of Engine Casing Temperature Constraints for Casing Mounted Electronics

NASA Technical Reports Server (NTRS)

Kratz, Jonathan L.; Culley, Dennis E.; Chapman, Jeffryes W.

2017-01-01

The performance of propulsion engine systems is sensitive to weight and volume considerations. This can severely constrain the configuration and complexity of the control system hardware. Distributed Engine Control technology is a response to these concerns by providing more flexibility in designing the control system, and by extension, more functionality leading to higher performing engine systems. Consequently, there can be a weight benefit to mounting modular electronic hardware on the engine core casing in a high temperature environment. This paper attempts to quantify the in-flight temperature constraints for engine casing mounted electronics. In addition, an attempt is made at studying heat soak back effects. The Commercial Modular Aero Propulsion System Simulation 40k (C-MAPSS40k) software is leveraged with real flight data as the inputs to the simulation. A two-dimensional (2-D) heat transfer model is integrated with the engine simulation to approximate the temperature along the length of the engine casing. This modification to the existing C-MAPSS40k software will provide tools and methodologies to develop a better understanding of the requirements for the embedded electronics hardware in future engine systems. Results of the simulations are presented and their implications on temperature constraints for engine casing mounted electronics is discussed.

Approximation of Engine Casing Temperature Constraints for Casing Mounted Electronics

NASA Technical Reports Server (NTRS)

Kratz, Jonathan; Culley, Dennis; Chapman, Jeffryes

2016-01-01

The performance of propulsion engine systems is sensitive to weight and volume considerations. This can severely constrain the configuration and complexity of the control system hardware. Distributed Engine Control technology is a response to these concerns by providing more flexibility in designing the control system, and by extension, more functionality leading to higher performing engine systems. Consequently, there can be a weight benefit to mounting modular electronic hardware on the engine core casing in a high temperature environment. This paper attempts to quantify the in-flight temperature constraints for engine casing mounted electronics. In addition, an attempt is made at studying heat soak back effects. The Commercial Modular Aero Propulsion System Simulation 40k (C-MAPSS40k) software is leveraged with real flight data as the inputs to the simulation. A two-dimensional (2-D) heat transfer model is integrated with the engine simulation to approximate the temperature along the length of the engine casing. This modification to the existing C-MAPSS40k software will provide tools and methodologies to develop a better understanding of the requirements for the embedded electronics hardware in future engine systems. Results of the simulations are presented and their implications on temperature constraints for engine casing mounted electronics is discussed.

Energy Savings by Treating Buildings as Systems

NASA Astrophysics Data System (ADS)

Harvey, L. D. Danny

2008-09-01

This paper reviews the opportunities for dramatically reducing energy use in buildings by treating buildings as systems, rather than focusing on device efficiencies. Systems-level considerations are relevant for the operation of heat pumps (where the temperatures at which heat or coldness are distributed are particularly important); the joint or separate provision of heating, cooling, and ventilation; the joint or separate removal of sensible heat and moisture; and in the operation of fluid systems having pumps. Passive heating, cooling, and ventilation, as well as daylighting (use of sunlight for lighting purposes) also require consideration of buildings as systems. In order to achieve the significant (50-75%) energy savings that are possible through a systems approach, the design process itself has to involve a high degree of integration between the architect and various engineering disciplines (structural, mechanical, electrical), and requires the systematic examination and adjustment of alternative designs using computer simulation models.

Issues to be addressed in the design and fabrication of ultralightweight meter-class optics

NASA Astrophysics Data System (ADS)

Krumweide, Gary C.

1998-08-01

There is a growing need for large aperture, ultralightweight, deployable optics for various science, military and commercial compact satellites. This paper will examine the engineering and manufacturing considerations that must be addressed in order to satisfy the requirements for these sought after optics. In order to limit the scope of this paper, only Graphite Fiber Reinforced/Polymer Matrix Composites (GFR/PMC) will be under consideration because of the potential to satisfy ultralightweight mirror requirements. The requirements associated with specular mirror concepts that Composite Optics, Incorporated (COI) has proposed to Air Force Research Laboratory and NASA Langley Research Center for visible range optics and LIDAR optics, respectively, will also be our interest. Moreover, it is the intent of this paper to illustrate how COI's proposed design/manufacturing concepts for visible and LIDAR optics have evolved based on overcoming, or working around, material constraints and/or undesirable characteristics associated with GFR/PMC.

Defining the Ecological Coefficient of Performance for an Aircraft Propulsion System

NASA Astrophysics Data System (ADS)

Şöhret, Yasin

2018-05-01

The aircraft industry, along with other industries, is considered responsible these days regarding environmental issues. Therefore, the performance evaluation of aircraft propulsion systems should be conducted with respect to environmental and ecological considerations. The current paper aims to present the ecological coefficient of performance calculation methodology for aircraft propulsion systems. The ecological coefficient performance is a widely-preferred performance indicator of numerous energy conversion systems. On the basis of thermodynamic laws, the methodology used to determine the ecological coefficient of performance for an aircraft propulsion system is parametrically explained and illustrated in this paper for the first time. For a better understanding, to begin with, the exergy analysis of a turbojet engine is described in detail. Following this, the outputs of the analysis are employed to define the ecological coefficient of performance for a turbojet engine. At the end of the study, the ecological coefficient of performance is evaluated parametrically and discussed depending on selected engine design parameters and performance measures. The author asserts the ecological coefficient of performance to be a beneficial indicator for researchers interested in aircraft propulsion system design and related topics.

Application of management tools to integrate ecological principles with the design of marine infrastructure.

PubMed

Dafforn, Katherine A; Mayer-Pinto, Mariana; Morris, Rebecca L; Waltham, Nathan J

2015-08-01

Globally the coastal zone is suffering the collateral damage from continuing urban development and construction, expanding resource sectors, increasing population, regulation to river flow, and on-going land change and degradation. While protection of natural coastal habitat is recommended, balancing conservation with human services is now the challenge for managers. Marine infrastructure such as seawalls, marinas and offshore platforms is increasingly used to support and provide services, but has primarily been designed for engineering purposes without consideration of the ecological consequences. Increasingly developments are seeking alternatives to hard engineering and a range of ecological solutions has begun to replace or be incorporated into marine and coastal infrastructure. But too often, hard engineering remains the primary strategy because the tools for managers to implement ecological solutions are either lacking or not supported by policy and stakeholders. Here we outline critical research needs for marine urban development and emerging strategies that seek to mitigate the impacts of marine infrastructure. We present case studies to highlight the strategic direction necessary to support management decisions internationally. Copyright © 2015 Elsevier Ltd. All rights reserved.

ThermoData Engine (TDE): software implementation of the dynamic data evaluation concept. 5. Experiment planning and product design.

PubMed

Diky, Vladimir; Chirico, Robert D; Kazakov, Andrei F; Muzny, Chris D; Magee, Joseph W; Abdulagatov, Ilmutdin; Kang, Jeong Won; Kroenlein, Kenneth; Frenkel, Michael

2011-01-24

ThermoData Engine (TDE) is the first full-scale software implementation of the dynamic data evaluation concept, as reported recently in this journal. In the present paper, we describe development of an algorithmic approach to assist experiment planning through assessment of the existing body of knowledge, including availability of experimental thermophysical property data, variable ranges studied, associated uncertainties, state of prediction methods, and parameters for deployment of prediction methods and how these parameters can be obtained using targeted measurements, etc., and, indeed, how the intended measurement may address the underlying scientific or engineering problem under consideration. A second new feature described here is the application of the software capabilities for aid in the design of chemical products through identification of chemical systems possessing desired values of thermophysical properties within defined ranges of tolerance. The algorithms and their software implementation to achieve this are described. Finally, implementation of a new data validation and weighting system is described for vapor-liquid equilibrium (VLE) data, and directions for future enhancements are outlined.

Centrifugal Compressor Aeroelastic Analysis Code

NASA Astrophysics Data System (ADS)

Keith, Theo G., Jr.; Srivastava, Rakesh

2002-01-01

Centrifugal compressors are very widely used in the turbomachine industry where low mass flow rates are required. Gas turbine engines for tanks, rotorcraft and small jets rely extensively on centrifugal compressors for rugged and compact design. These compressors experience problems related with unsteadiness of flowfields, such as stall flutter, separation at the trailing edge over diffuser guide vanes, tip vortex unsteadiness, etc., leading to rotating stall and surge. Considerable interest exists in small gas turbine engine manufacturers to understand and eventually eliminate the problems related to centrifugal compressors. The geometric complexity of centrifugal compressor blades and the twisting of the blade passages makes the linear methods inapplicable. Advanced computational fluid dynamics (CFD) methods are needed for accurate unsteady aerodynamic and aeroelastic analysis of centrifugal compressors. Most of the current day industrial turbomachines and small aircraft engines are designed with a centrifugal compressor. With such a large customer base and NASA Glenn Research Center being, the lead center for turbomachines, it is important that adequate emphasis be placed on this area as well. Currently, this activity is not supported under any project at NASA Glenn.

Lyotropic liquid crystal engineering moving beyond binary compositional space - ordered nanostructured amphiphile self-assembly materials by design.

PubMed

van 't Hag, Leonie; Gras, Sally L; Conn, Charlotte E; Drummond, Calum J

2017-05-22

Ordered amphiphile self-assembly materials with a tunable three-dimensional (3D) nanostructure are of fundamental interest, and crucial for progressing several biological and biomedical applications, including in meso membrane protein crystallization, as drug and medical contrast agent delivery vehicles, and as biosensors and biofuel cells. In binary systems consisting of an amphiphile and a solvent, the ability to tune the 3D cubic phase nanostructure, lipid bilayer properties and the lipid mesophase is limited. A move beyond the binary compositional space is therefore required for efficient engineering of the required material properties. In this critical review, the phase transitions upon encapsulation of more than 130 amphiphilic and soluble additives into the bicontinuous lipidic cubic phase under excess hydration are summarized. The data are interpreted using geometric considerations, interfacial curvature, electrostatic interactions, partition coefficients and miscibility of the alkyl chains. The obtained lyotropic liquid crystal engineering design rules can be used to enhance the formulation of self-assembly materials and provides a large library of these materials for use in biomedical applications (242 references).

Cybernetic systems based on inductive logic

NASA Astrophysics Data System (ADS)

Fry, Robert L.

2001-05-01

Recent work in the area of inductive logic suggests that cybernetics might be quantified and reduced to engineering practice. If so, then there are considerable implications for engineering, science, and other fields. This paper attempts to capture the essential ideas of cybernetics cast in the light of inductive logic. The described inductive logic extends conventional logic by adding a conjugate logical domain of questions to the logical domain of assertions intrinsic to Boolean Algebra with which most are familiar. This was first posited and developed by Richard Cox. Interestingly enough, these two logical domains, one of questions and the other of assertions, only exist relative to one another with each possessing natural measures of entropy and probability, respectively. Examples are given that highlight the utility of cybernetic approaches to neuroscience, algorithm design, system engineering, and the design and understanding of defensive and offensive systems. For example, the application of cybernetic approaches to defense systems suggests that these systems possess a wavefunction which like quantum mechanics, collapses when we ``look'' through the eyes of the system sensors such as radars and optical sensors. .

Engineering Metallic Nanoparticles for Enhancing and Probing Catalytic Reactions.

PubMed

Collins, Gillian; Holmes, Justin D

2016-07-01

Recent developments in tailoring the structural and chemical properties of colloidal metal nanoparticles (NPs) have led to significant enhancements in catalyst performance. Controllable colloidal synthesis has also allowed tailor-made NPs to serve as mechanistic probes for catalytic processes. The innovative use of colloidal NPs to gain fundamental insights into catalytic function will be highlighted across a variety of catalytic and electrocatalytic applications. The engineering of future heterogenous catalysts is also moving beyond size, shape and composition considerations. Advancements in understanding structure-property relationships have enabled incorporation of complex features such as tuning surface strain to influence the behavior of catalytic NPs. Exploiting plasmonic properties and altering colloidal surface chemistry through functionalization are also emerging as important areas for rational design of catalytic NPs. This news article will highlight the key developments and challenges to the future design of catalytic NPs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Deep sequencing in library selection projects: what insight does it bring?

PubMed

Glanville, J; D'Angelo, S; Khan, T A; Reddy, S T; Naranjo, L; Ferrara, F; Bradbury, A R M

2015-08-01

High throughput sequencing is poised to change all aspects of the way antibodies and other binders are discovered and engineered. Millions of available sequence reads provide an unprecedented sampling depth able to guide the design and construction of effective, high quality naïve libraries containing tens of billions of unique molecules. Furthermore, during selections, high throughput sequencing enables quantitative tracing of enriched clones and position-specific guidance to amino acid variation under positive selection during antibody engineering. Successful application of the technologies relies on specific PCR reagent design, correct sequencing platform selection, and effective use of computational tools and statistical measures to remove error, identify antibodies, estimate diversity, and extract signatures of selection from the clone down to individual structural positions. Here we review these considerations and discuss some of the remaining challenges to the widespread adoption of the technology. Copyright © 2015 Elsevier Ltd. All rights reserved.

Deep sequencing in library selection projects: what insight does it bring?

PubMed Central

Glanville, J; D’Angelo, S; Khan, T.A.; Reddy, S. T.; Naranjo, L.; Ferrara, F.; Bradbury, A.R.M.

2015-01-01

High throughput sequencing is poised to change all aspects of the way antibodies and other binders are discovered and engineered. Millions of available sequence reads provide an unprecedented sampling depth able to guide the design and construction of effective, high quality naïve libraries containing tens of billions of unique molecules. Furthermore, during selections, high throughput sequencing enables quantitative tracing of enriched clones and position-specific guidance to amino acid variation under positive selection during antibody engineering. Successful application of the technologies relies on specific PCR reagent design, correct sequencing platform selection, and effective use of computational tools and statistical measures to remove error, identify antibodies, estimate diversity, and extract signatures of selection from the clone down to individual structural positions. Here we review these considerations and discuss some of the remaining challenges to the widespread adoption of the technology. PMID:26451649

CFD for hypersonic propulsion

NASA Technical Reports Server (NTRS)

Povinelli, Louis A.

1991-01-01

An overview is given of research activity on the application of computational fluid dynamics (CDF) for hypersonic propulsion systems. After the initial consideration of the highly integrated nature of air-breathing hypersonic engines and airframe, attention is directed toward computations carried out for the components of the engine. A generic inlet configuration is considered in order to demonstrate the highly three dimensional viscous flow behavior occurring within rectangular inlets. Reacting flow computations for simple jet injection as well as for more complex combustion chambers are then discussed in order to show the capability of viscous finite rate chemical reaction computer simulations. Finally, the nozzle flow fields are demonstrated, showing the existence of complex shear layers and shock structure in the exhaust plume. The general issues associated with code validation as well as the specific issue associated with the use of CFD for design are discussed. A prognosis for the success of CFD in the design of future propulsion systems is offered.

CFD for hypersonic propulsion

NASA Technical Reports Server (NTRS)

Povinelli, Louis A.

1990-01-01

An overview is given of research activity on the application of computational fluid dynamics (CDF) for hypersonic propulsion systems. After the initial consideration of the highly integrated nature of air-breathing hypersonic engines and airframe, attention is directed toward computations carried out for the components of the engine. A generic inlet configuration is considered in order to demonstrate the highly three dimensional viscous flow behavior occurring within rectangular inlets. Reacting flow computations for simple jet injection as well as for more complex combustion chambers are then discussed in order to show the capability of viscous finite rate chemical reaction computer simulations. Finally, the nozzle flow fields are demonstrated, showing the existence of complex shear layers and shock structure in the exhaust plume. The general issues associated with code validation as well as the specific issue associated with the use of CFD for design are discussed. A prognosis for the success of CFD in the design of future propulsion systems is offered.

Tissue engineering strategies in spinal arthrodesis: the clinical imperative and challenges to clinical translation.

PubMed

Evans, Nick R; Davies, Evan M; Dare, Chris J; Oreffo, Richard Oc

2013-01-01

Skeletal disorders requiring the regeneration or de novo production of bone present considerable reconstructive challenges and are one of the main driving forces for the development of skeletal tissue engineering strategies. The skeletal or mesenchymal stem cell is a fundamental requirement for osteogenesis and plays a pivotal role in the design and application of these strategies. Research activity has focused on incorporating the biological role of the mesenchymal stem cell with the developing fields of material science and gene therapy in order to create a construct that is not only capable of inducing host osteoblasts to produce bone, but is also osteogenic in its own right. This review explores the clinical need for reparative approaches in spinal arthrodesis, identifying recent tissue engineering strategies employed to promote spinal fusion, and considers the ongoing challenges to successful clinical translation.

Off-line programming motion and process commands for robotic welding of Space Shuttle main engines

NASA Technical Reports Server (NTRS)

Ruokangas, C. C.; Guthmiller, W. A.; Pierson, B. L.; Sliwinski, K. E.; Lee, J. M. F.

1987-01-01

The off-line-programming software and hardware being developed for robotic welding of the Space Shuttle main engine are described and illustrated with diagrams, drawings, graphs, and photographs. The menu-driven workstation-based interactive programming system is designed to permit generation of both motion and process commands for the robotic workcell by weld engineers (with only limited knowledge of programming or CAD systems) on the production floor. Consideration is given to the user interface, geometric-sources interfaces, overall menu structure, weld-parameter data base, and displays of run time and archived data. Ongoing efforts to address limitations related to automatic-downhand-configuration coordinated motion, a lack of source codes for the motion-control software, CAD data incompatibility, interfacing with the robotic workcell, and definition of the welding data base are discussed.

Experimental Study of Ignition by Hot Spot in Internal Combustion Engines

NASA Technical Reports Server (NTRS)

Serruys, Max

1938-01-01

In order to carry out the contemplated study, it was first necessary to provide hot spots in the combustion chamber, which could be measured and whose temperature could be changed. It seemed difficult to realize both conditions working solely on the temperature of the cooling water in a way so as to produce hot spots on the cylinder wall capable of provoking autoignition. Moreover, in the majority of practical cases, autoignition is produced by the spark plug, one of the least cooled parts in the engine. The first procedure therefore did not resemble that which most generally occurs in actual engine operation. All of these considerations caused us to reproduce similar hot spots at the spark plugs. The hot spots produced were of two kinds and designated with the name of thermo-electric spark plug and of metallic hot spot.

The Engagement of Engineers in Education and Public Outreach: Beginning the Conversation

NASA Astrophysics Data System (ADS)

Grier, J.; Buxner, S.; Vezino, B.; Shipp, S. S.

2014-12-01

The Next Generation Science Standards (NGSS) are a new set of K-12 science standards that have been developed through a collaborative, state-led process. Based on the National Research Council (NRC) 'Framework for K-12 Education,' the NGSS are designed to provide all students with a coherent education possessing both robust content and rigorous practice. Within these standards is an enhanced emphasis on the intersection between science and engineering. The focus is not only on asking questions and finding answers (science) but also in identifying and designing solution to problems (engineering.) The NASA SMD (Science Mission Directorate) Education and Public Outreach (E/PO) Forums have been working with space scientists for many years to assist with their engagement in E/PO efforts, thus supporting the needs of previous science standards. In order to properly address the needs of NGSS, this conversation is being expanded to include engineers. Our initial efforts include a series of semi-structured interviews with a dozen engineers involved in different aspects of space science and mission development. We will present the responses from the survey and compare this information to our knowledge base about space scientists, their needs, attitudes, and understandings of E/PO. In addition to a new emphasis on engineering in the NGSS, we also consider engineering habits of mind such as systems thinking, creativity, optimism, collaboration, communication, and attention to ethical considerations as described by an NRC policy document for engineering education. Using the overall results, we will consider strategies, further ideas for investigation, and possible steps for going forward with this important aspect of including engineering in education and outreach programming.

Role to Be Played by Independent Geotechnical Supervision in the Foundation for Bridge Construction

NASA Astrophysics Data System (ADS)

Sobala, Dariusz; Rybak, Jarosław

2017-10-01

Some remarks concerning the necessity of employing an independent and over all ethical geotechnical survey were presented in the paper. Starting from the design phase, through the whole construction process, the importance of geotechnical engineer is stated in legal acts. Numerous testing technologies serve for the calibration of geotechnical technologies and allow for confirming the quality and capacity of piles. Special emphasis was payed to the involvement of scientifical and research institutions which can not only serve services but also can postprocess and methodize collected data. Such databases enable for new codes, methods and recommendations. Selection of deep foundations for bridge-type structures is most often dependent on complex geotechnical conditions, concentrated loads and constraints for pier displacements. Besides the last ones, prior to more common introduction of the design-construct system, could be a convenient justification for design engineer, who imposed deep foundation because he did not want or was not able to estimate the effect of pier settlement on civil engineering structure. The paper provides some notes about the need to engage a geotechnical supervising service of high competency and ethical quality during engineering and construction stages of foundations for bridge-type structures where legal requirements are of special consideration. Successive stages of projects are reviewed and research methods used for current calibration of geotechnical technologies and verification of geotechnical work quality are analysed. Special attention is given to potential involvement of independent R&D institutions which, apart from rendering specific services, also collect and systemize the research results thus enabling, in the long term, to revise engineering standards, instructions and guidelines.

Pratt and Whitney J57 with a Greatex Nozzle in the Altitude Wind Tunnel

NASA Image and Video Library

1957-02-21

A Pratt and Whitney J57 engine is tested with a Greatex No.1 nozzle in the Altitude Wind Tunnel at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. At the time the aircraft industry was preparing to introduce jet airliners to the nation’s airways. The noise produced by the large jet engines, however, posed a considerable problem for communities near airports. The NACA had formed a Special Subcommittee on Aircraft Noise to coordinate research on the issue. Preliminary tests showed that the source of the loudest noise was not the engine itself, but the mixing of the engine’s exhaust with the surrounding air in the atmosphere. The pressures resulting from this turbulence produced sound waves. Lewis researchers undertook a variety of noise-reduction studies involving engine design, throttling procedures, and noise suppressors. One of their first efforts focused on new types of nozzles to mix the exhaust with the surrounding air. The nozzles had a variety of shapes designed to slow down exhaust velocity before it combined with the air and thus decrease the noise. From January to May 1957 a Pratt and Whitney J57 engine was equipped with various shaped nozzles, as seen in this photograph, and run in simulated flight conditions in the Altitude Wind Tunnel. A number of nozzle configurations, including several multi-exit “organ pipe” designs, were created. It was found that the various nozzle types did reduce the noise levels, but they also reduced the aircraft’s thrust.

Solar Mesosphere Explorer optical-mechanical systems engineering

NASA Technical Reports Server (NTRS)

Gause, K. A.; Stuart, J. R.

1979-01-01

Mission overview of the Solar Mesosphere Explorer is presented along with design analysis and summaries of results. The Solar Mesosphere Explorer is a spin stabilized satellite carrying a complement of four Ebert-Fastie spectrometers and a four-channel Mersenne radiometer. Description of the spectrometer is given including a telescope and its aberrations. The radiometer is also described with consideration given to isothermal and thermal design, a Winston paraboloid, and optical tolerances. These five instruments are for measuring the earth's ozone density and distribution and providing quantitative data about those processes which govern the formation and destruction of ozone.

Laboratory and Industrial Ventilation

NASA Technical Reports Server (NTRS)

1972-01-01

This handbook supplements the Facilities Engineering Handbook (NHB 7320.1) and provides additional policies and criteria for uniform application to ventilation systems. It expands basic requirements, provides additional design and construction guidance, and places emphasis on those design considerations which will provide for greater effectiveness in the use of these systems. The provisions of this handbook are applicable to all NASA field installations and the Jet Propulsion Laboratory. Since supply of this handbook is limited, abstracts of the portion or portions applicable to a given requirement will be made for the individual specific needs encountered rather than supplying copies of the handbook as has been past practice.

Human supervision and microprocessor control of an optical tracking system

NASA Technical Reports Server (NTRS)

Bigley, W. J.; Vandenberg, J. D.

1981-01-01

Gunners using small calibre anti-aircraft systems have not been able to track high-speed air targets effectively. Substantial improvement in the accuracy of surface fire against attacking aircraft has been realized through the design of a director-type weapon control system. This system concept frees the gunner to exercise a supervisory/monitoring role while the computer takes over continuous target tracking. This change capitalizes on a key consideration of human factors engineering while increasing system accuracy. The advanced system design, which uses distributed microprocessor control, is discussed at the block diagram level and is contrasted with the previous implementation.

Technology developments toward 30-year-life of photovoltaic modules

NASA Technical Reports Server (NTRS)

Ross, R. G., Jr.

1984-01-01

As part of the United States National Photovoltaics Program, the Jet Propulsion Laboratory's Flat-Plate Solar Array Project (FSA) has maintained a comprehensive reliability and engineering sciences activity addressed toward understanding the reliability attributes of terrestrial flat-plate photovoltaic arrays and to deriving analysis and design tools necessary to achieve module designs with a 30-year useful life. The considerable progress to date stemming from the ongoing reliability research is discussed, and the major areas requiring continued research are highlighted. The result is an overview of the total array reliability problem and of available means of achieving high reliability at minimum cost.

Jet noise suppressor nozzle development for augmentor wing jet STOL research aircraft (C-8A Buffalo)

NASA Technical Reports Server (NTRS)

Harkonen, D. L.; Marks, C. C.; Okeefe, J. V.

1974-01-01

Noise and performance test results are presented for a full-scale advanced design rectangular array lobe jet suppressor nozzle (plain wall and corrugated). Flight design and installation considerations are also discussed. Noise data are presented in terms of peak PNLT (perceived noise level, tone corrected) suppression relative to the existing airplane and one-third octave-band spectra. Nozzle performance is presented in terms of velocity coefficient. Estimates of the hot thrust available during emergency (engine out) with the suppressor nozzle installed are compared with the current thrust levels produced by the round convergent nozzles.

A Requirements-Driven Optimization Method for Acoustic Treatment Design

NASA Technical Reports Server (NTRS)

Berton, Jeffrey J.

2016-01-01

Acoustic treatment designers have long been able to target specific noise sources inside turbofan engines. Facesheet porosity and cavity depth are key design variables of perforate-over-honeycomb liners that determine levels of noise suppression as well as the frequencies at which suppression occurs. Layers of these structures can be combined to create a robust attenuation spectrum that covers a wide range of frequencies. Looking to the future, rapidly-emerging additive manufacturing technologies are enabling new liners with multiple degrees of freedom, and new adaptive liners with variable impedance are showing promise. More than ever, there is greater flexibility and freedom in liner design. Subject to practical considerations, liner design variables may be manipulated to achieve a target attenuation spectrum. But characteristics of the ideal attenuation spectrum can be difficult to know. Many multidisciplinary system effects govern how engine noise sources contribute to community noise. Given a hardwall fan noise source to be suppressed, and using an analytical certification noise model to compute a community noise measure of merit, the optimal attenuation spectrum can be derived using multidisciplinary systems analysis methods. The subject of this paper is an analytical method that derives the ideal target attenuation spectrum that minimizes noise perceived by observers on the ground.

76 FR 45011 - Control of Air Pollution From Aircraft and Aircraft Engines; Proposed Emission Standards and Test...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-27

...This action proposes several new NOX emission standards, compliance flexibilities, and other regulatory requirements for aircraft turbofan or turbojet engines with rated thrusts greater than 26.7 kilonewtons (kN). We also are proposing certain other requirements for gas turbine engines that are subject to exhaust emission standards. First, we are proposing to clarify when the emission characteristics of a new turbofan or turbojet engine model have become different enough from its existing parent engine design that it must conform to the most current emission standards. Second, we are proposing a new reporting requirement for manufacturers of gas turbine engines that are subject to any exhaust emission standard to provide us with timely and consistent emission-related information. Third, and finally, we are proposing amendments to aircraft engine test and emissions measurement procedures. EPA actively participated in the United Nation's International Civil Aviation Organization (ICAO) proceedings in which most of these proposed requirements were first developed. These proposed regulatory requirements have largely been adopted or are actively under consideration by its member states. By adopting such similar standards, therefore, the United States will maintain consistency with these international efforts.

Performance Evaluation of Particle Sampling Probes for Emission Measurements of Aircraft Jet Engines

NASA Technical Reports Server (NTRS)

Lee, Poshin; Chen, Da-Ren; Sanders, Terry (Technical Monitor)

2001-01-01

Considerable attention has been recently received on the impact of aircraft-produced aerosols upon the global climate. Sampling particles directly from jet engines has been performed by different research groups in the U.S. and Europe. However, a large variation has been observed among published data on the conversion efficiency and emission indexes of jet engines. The variation results surely from the differences in test engine types, engine operation conditions, and environmental conditions. The other factor that could result in the observed variation is the performance of sampling probes used. Unfortunately, it is often neglected in the jet engine community. Particle losses during the sampling, transport, and dilution processes are often not discussed/considered in literatures. To address this issue, we evaluated the performance of one sampling probe by challenging it with monodisperse particles. A significant performance difference was observed on the sampling probe evaluated under different temperature conditions. Thermophoretic effect, nonisokinetic sampling and turbulence loss contribute to the loss of particles in sampling probes. The results of this study show that particle loss can be dramatic if the sampling probe is not well designed. Further, the result allows ones to recover the actual size distributions emitted from jet engines.

The Role of the Strutjet Engine in New Global and Space Markets

NASA Technical Reports Server (NTRS)

Siebenhaar, A.; Bulman, M. J.; Bonnar, D. K.

1998-01-01

The Strutjet, discussed in previous IAF papers, was originally introduced as an enabling propulsion concept for single stage to orbit applications. Recent design considerations indicate that this systems also provides benefits supportive of other commercial non-space applications. This paper describes the technical progress of the Strutjet since 1997 together with a rationale why Rocket Based Combined Cycle Engines in general, and the Strutjet in particular, lend themselves uniquely to systems having the ability to expand current space and open new global 'rapid delivery' markets. During this decade, Strutjet technology has been evaluated in over 1000 tests. Its design maturity has been continuously improved and desired features, like simple variable geometry and low drag flowpath resulting in high performance, have been verified. In addition, data is now available which allows the designer, who is challenged to maximize system operability and economic feasibility, to choose between hydrogen or hydrocarbon fuels for a variety of application. The ability exists now to apply this propulsion system to various vehicles with a multitude of missions. In this paper, storable hydrocarbon and gaseous hydrogen Strutjet RBCC test data as accomplished to date and as planned for the future is presented, and the degree of required technology maturity achieved so far is assessed. Two vehicles, using cryogenic propane fuel Strutjet engines, and specifically designed for rapid point-to-point cargo delivery between Pacific rim locations are introduced, discussed, and compared.

a Framework for AN Automatic Seamline Engine

NASA Astrophysics Data System (ADS)

Al-Durgham, M.; Downey, M.; Gehrke, S.; Beshah, B. T.

2016-06-01

Seamline generation is a crucial last step in the ortho-image mosaicking process. In particular, it is required to convolute residual geometric and radiometric imperfections that stem from various sources. In particular, temporal differences in the acquired data will cause the scene content and illumination conditions to vary. These variations can be modelled successfully. However, one is left with micro-differences that do need to be considered in seamline generation. Another cause of discrepancies originates from the rectification surface as it will not model the actual terrain and especially human-made objects perfectly. Quality of the image orientation will also contribute to the overall differences between adjacent ortho-rectified images. Our approach takes into consideration the aforementioned differences in designing a seamline engine. We have identified the following essential behaviours of the seamline in our engine: 1) Seamlines must pass through the path of least resistance, i.e., overlap areas with low radiometric differences. 2) Seamlines must not intersect with breaklines as that will lead to visible geometric artefacts. And finally, 3), shorter seamlines are generally favourable; they also result in faster operator review and, where necessary, interactive editing cycles. The engine design also permits alteration of the above rules for special cases. Although our preliminary experiments are geared towards line imaging systems (i.e., the Leica ADS family), our seamline engine remains sensor agnostic. Hence, our design is capable of mosaicking images from various sources with minimal effort. The main idea behind this engine is using graph cuts which, in spirit, is based of the max-flow min-cut theory. The main advantage of using graph cuts theory is that the generated solution is global in the energy minimization sense. In addition, graph cuts allows for a highly scalable design where a set of rules contribute towards a cost function which, in turn, influences the path of minimum resistance for the seamlines. In this paper, the authors present an approach for achieving quality seamlines relatively quickly and with emphasis on generating truly seamless ortho-mosaics.

A distributed version of the NASA Engine Performance Program

NASA Technical Reports Server (NTRS)

Cours, Jeffrey T.; Curlett, Brian P.

1993-01-01

Distributed NEPP, a version of the NASA Engine Performance Program, uses the original NEPP code but executes it in a distributed computer environment. Multiple workstations connected by a network increase the program's speed and, more importantly, the complexity of the cases it can handle in a reasonable time. Distributed NEPP uses the public domain software package, called Parallel Virtual Machine, allowing it to execute on clusters of machines containing many different architectures. It includes the capability to link with other computers, allowing them to process NEPP jobs in parallel. This paper discusses the design issues and granularity considerations that entered into programming Distributed NEPP and presents the results of timing runs.

Propulsion system study for Small Transport Aircraft Technology (STAT)

NASA Technical Reports Server (NTRS)

Smith, C. E.; Hirschkron, R.; Warren, R. E.

1981-01-01

Propulsion system technologies applicable to the generation of commuter airline aircraft expected to enter service in the 1990's are identified and evaluated in terms of their impact on aircraft operating economics and fuel consumption. The most promising technologies in the areas of engine, propeller, gearbox, and nacelle design are recommended for future research. Each item under consideration is evaluated relative to a modern baseline engine, the General Electric CT7-5, in a current technology aircraft flying a fixed range and payload. The analysis is presented for two aircraft sizes (30 and 50 passenger), over a range of mission lengths (100 to 1100 km) and fuel costs ($264 to $396 per cu m).

Upgrades to the NESS (Nuclear Engine System Simulation) Code

NASA Technical Reports Server (NTRS)

Fittje, James E.

2007-01-01

In support of the President's Vision for Space Exploration, the Nuclear Thermal Rocket (NTR) concept is being evaluated as a potential propulsion technology for human expeditions to the moon and Mars. The need for exceptional propulsion system performance in these missions has been documented in numerous studies, and was the primary focus of a considerable effort undertaken during the 1960's and 1970's. The NASA Glenn Research Center is leveraging this past NTR investment in their vehicle concepts and mission analysis studies with the aid of the Nuclear Engine System Simulation (NESS) code. This paper presents the additional capabilities and upgrades made to this code in order to perform higher fidelity NTR propulsion system analysis and design.

Description of operation of fast-response solenoid actuator in diesel fuel system model

NASA Astrophysics Data System (ADS)

Zhao, J.; Grekhov, L. V.; Fan, L.; Ma, X.; Song, E.

2018-03-01

The performance of the fast-response solenoid actuator (FRSA) of engine fuel systems is characterized by the response time of less than 0.1 ms and the necessity to take into consideration the non-stationary peculiarities of mechanical, hydraulic, electrical and magnetic processes. Simple models for magnetization in static and dynamic hysteresis are used for this purpose. The experimental study of the FRSA performance within the electro-hydraulic injector of the Common Rail demonstrated an agreement between the computational and experimental results. The computation of the processes is not only a tool for analysis, but also a tool for design and optimization of the solenoid actuator of new engine fuels systems.

Litho hotspots fixing using model based algorithm

NASA Astrophysics Data System (ADS)

Zhang, Meili; Yu, Shirui; Mao, Zhibiao; Shafee, Marwa; Madkour, Kareem; ElManhawy, Wael; Kwan, Joe; Hu, Xinyi; Wan, Qijian; Du, Chunshan

2017-04-01

As technology advances, IC designs are getting more sophisticated, thus it becomes more critical and challenging to fix printability issues in the design flow. Running lithography checks before tapeout is now mandatory for designers, which creates a need for more advanced and easy-to-use techniques for fixing hotspots found after lithographic simulation without creating a new design rule checking (DRC) violation or generating a new hotspot. This paper presents a new methodology for fixing hotspots on layouts while using the same engine currently used to detect the hotspots. The fix is achieved by applying minimum movement of edges causing the hotspot, with consideration of DRC constraints. The fix is internally simulated by the lithographic simulation engine to verify that the hotspot is eliminated and that no new hotspot is generated by the new edge locations. Hotspot fix checking is enhanced by adding DRC checks to the litho-friendly design (LFD) rule file to guarantee that any fix options that violate DRC checks are removed from the output hint file. This extra checking eliminates the need to re-run both DRC and LFD checks to ensure the change successfully fixed the hotspot, which saves time and simplifies the designer's workflow. This methodology is demonstrated on industrial designs, where the fixing rate of single and dual layer hotspots is reported.

Summary of Lift and Lift/Cruise Fan Powered Lift Concept Technology

NASA Technical Reports Server (NTRS)

Cook, Woodrow L.

1993-01-01

A summary is presented of some of the lift and lift/cruise fan technology including fan performance, fan stall, ground effects, ingestion and thrust loss, design tradeoffs and integration, control effectiveness and several other areas related to vertical short takeoff and landing (V/STOL) aircraft conceptual design. The various subjects addressed, while not necessarily pertinent to specific short takeoff/vertical landing (STOVL) supersonic designs being considered, are of interest to the general field of lift and lift/cruise fan aircraft designs and may be of importance in the future. The various wind tunnel and static tests reviewed are: (1) the Doak VZ-4 ducted fan, (2) the 0.57 scale model of the Bell X-22 ducted fan aircraft, (3) the Avrocar, (4) the General Electric lift/cruise fan, (5) the vertical short takeoff and landing (V/STOL) lift engine configurations related to ingestion and consequent thrust loss, (6) the XV-5 and other fan-in-wing stall consideration, (7) hybrid configurations such as lift fan and lift/cruise fan or engines, and (8) the various conceptual design studies by air-frame contractors. Other design integration problems related to small and large V/STOL transport aircraft are summarized including lessons learned during more recent conceptual design studies related to a small executive V/STOL transport aircraft.

An Analytical and Experimental Analysis of Factors Affecting Exhaust System Performance in Sea Level Static Jet Engine Test Facilities.

DTIC Science & Technology

1972-12-01

include filtering devices, venturi scrubbers , and electrostatic precipitators. These have been evaluated as unsatisfactory from considerations of...Early studies of pollution abatement systems have resulted in the selection and development of a nucleation scrubber [Ref. 47]. Other devices analyzed...the venturi system is its inability to operate efficiently over greater than a 10 percent interval away from its design point, which is an

Performance considerations for high-definition head-mounted displays

NASA Technical Reports Server (NTRS)

Edwards, Oliver J.; Larimer, James; Gille, Jennifer

1992-01-01

Design image-optimization for helmet-mounted displays (HMDs) for military systems is presently discussed within the framework of a systems-engineering approach that encompasses (1) a description of natural targets in the field; (2) the characteristics of human visual perception; and (3) device specifications that directly relate to these ecological and human-factors parameters. Attention is given to target size and contrast and the relationship of the modulation transfer function to image resolution.

Shuttle cryogenic supply system optimization study. Volume 2: Technical report, sections 4 through 9

NASA Technical Reports Server (NTRS)

1973-01-01

The design and development of cryogenic supply systems for space shuttle vehicles are discussed. The weights, component counts, and statements of advantages and disadvantages of the systems considered are presented. Performance characteristics of the systems are analyzed in the form of graphs. Block diagrams and engineering drawings of the candidate systems are provided. Special consideration is given to flow rates and thermodynamic properties of the cryogenic systems.

Application of the Moment Method in the Slip and Transition Regime for Microfluidic Flows

DTIC Science & Technology

2011-01-01

systems ( MEMS ), fluid flow at the micro- and nano-scale has received considerable attention [1]. A basic understanding of the nature of flow and heat ...Couette Flow Many MEMS devices contain oscillating parts where air (viscous) damping plays an important role. To understand the damping mechanisms...transfer in these devices is considered essential for efficient design and control of MEMS . Engineering applications for gas microflows include

Steel Structures for Civil Works, General Considerations for Design and Rehabilitation

DTIC Science & Technology

1993-08-01

34Weathering Steel Requires Proper Detailing," Chicago, IL. US Army Corps of Engineers. 1989. "Mechanical Properties and Corrosion Behavior of Stainless...types of corrosion and corro- sion protection are addressed. In Part X, authored by Dr. John Jaeger, vari- ous cases of distressed hydraulic steel ...guide in selecting a steel appropriate for a given application. Effects of alloying elements 8. Alloying elements are added to steel to effect

MEMS product engineering: methodology and tools

NASA Astrophysics Data System (ADS)

Ortloff, Dirk; Popp, Jens; Schmidt, Thilo; Hahn, Kai; Mielke, Matthias; Brück, Rainer

2011-03-01

The development of MEMS comprises the structural design as well as the definition of an appropriate manufacturing process. Technology constraints have a considerable impact on the device design and vice-versa. Product design and technology development are therefore concurrent tasks. Based on a comprehensive methodology the authors introduce a software environment that links commercial design tools from both area into a common design flow. In this paper emphasis is put on automatic low threshold data acquisition. The intention is to collect and categorize development data for further developments with minimum overhead and minimum disturbance of established business processes. As a first step software tools that automatically extract data from spreadsheets or file-systems and put them in context with existing information are presented. The developments are currently carried out in a European research project.

Computational Fluid Dynamics (CFD) Analysis for the Reduction of Impeller Discharge Flow Distortion

NASA Technical Reports Server (NTRS)

Garcia, R.; McConnaughey, P. K.; Eastland, A.

1993-01-01

The use of Computational Fluid Dynamics (CFD) in the design and analysis of high performance rocket engine pumps has increased in recent years. This increase has been aided by the activities of the Marshall Space Flight Center (MSFC) Pump Stage Technology Team (PSTT). The team's goals include assessing the accuracy and efficiency of several methodologies and then applying the appropriate methodology(s) to understand and improve the flow inside a pump. The PSTT's objectives, team membership, and past activities are discussed in Garcia1 and Garcia2. The PSTT is one of three teams that form the NASA/MSFC CFD Consortium for Applications in Propulsion Technology (McConnaughey3). The PSTT first applied CFD in the design of the baseline consortium impeller. This impeller was designed for the Space Transportation Main Engine's (STME) fuel turbopump. The STME fuel pump was designed with three impeller stages because a two-stage design was deemed to pose a high developmental risk. The PSTT used CFD to design an impeller whose performance allowed for a two-stage STME fuel pump design. The availability of this design would have lead to a reduction in parts, weight, and cost had the STME reached production. One sample of the baseline consortium impeller was manufactured and tested in a water rig. The test data showed that the impeller performance was as predicted and that a two-stage design for the STME fuel pump was possible with minimal risk. The test data also verified another CFD predicted characteristic of the design that was not desirable. The classical 'jet-wake' pattern at the impeller discharge was strengthened by two aspects of the design: by the high head coefficient necessary for the required pressure rise and by the relatively few impeller exit blades, 12, necessary to reduce manufacturing cost. This 'jet-wake pattern produces an unsteady loading on the diffuser vanes and has, in past rocket engine programs, lead to diffuser structural failure. In industrial applications, this problem is typically avoided by increasing the space between the impeller and the diffuser to allow the dissipation of this pattern and, hence, the reduction of diffuser vane unsteady loading. This approach leads to small performance losses and, more importantly in rocket engine applications, to significant increases in the pump's size and weight. This latter consideration typically makes this approach unacceptable in high performance rocket engines.

Investigation of Performance of Axial-Flow Compressor of XT-46 Turbine-Propeller Engine. I - Preliminary Investigation at 50-,70-, and 100-Percent Design Equivalent Speed

NASA Technical Reports Server (NTRS)

Creagh, John W.R.; Sandercrock, Donald M.

1950-01-01

An investigation is being conducted to determine the performance of the 12-stage axial-flow compressor of the XT-46 turbine-propeller engine. This compressor was designed to produce a pressure ratio of 9 at an adiabatic efficiency of 0.86. The design pressure ratios per stage were considerably greater than any employed in current aircraft gas-turbine engines using this type of compressor. The compressor performance was evaluated at two stations. The station near the entrance section of the combustors indicated a peak pressure ratio of 6.3 at an adiabatic efficiency of 0.63 for a corrected weight flow of 23.1 pounds per second. The other, located one blade-chord downstream of the last stator row, indicated a peak pressure ratio of 6.97 at an adiabatic efficiency of 0.81 for a corrected weight flow of 30.4 pounds per second. The difference in performance obtained at the two stations is attributed to shock waves in the vicinity of the last stator row. These shock waves and the accompanying flow choking, together with interstage circulatory flows, shift the compressor operating curves into the region where surge would normally occur. The inability of the compressor to meet design pressure ratio is probably due to boundary-layer buildup in the last stages, which cause axial velocities greater than design values that, in turn, adversely affect the angles of attack and turning angles in these blade rows.

Poisoning of bubble propelled catalytic micromotors: the chemical environment matters

PubMed Central

Zhao, Guanjia; Sanchez, Samuel; Schmidt, Oliver G.

2013-01-01

Self-propelled catalytic microjets have attracted considerable attention in recent years and these devices have exhibited the ability to move in complex media. The mechanism of propulsion is via the Pt catalysed decomposition of H2O2 and it is understood that the Pt surface is highly susceptible to poisoning by sulphur-containing molecules. Here, we show that important extracellular thiols as well as basic organic molecules can significantly hamper the motion of catalytic microjet engines. This is due to two different mechanisms: (i) molecules such as dimethyl sulfoxide can quench the hydroxyl radicals produced at Pt surfaces and reduce the amount of oxygen gas generated and (ii) molecules containing –SH, –SSR, and –SCH3 moieties can poison the catalytically active platinum surface, inhibiting the motion of the jet engines. It is essential that the presence of such molecules in the environment be taken into consideration for future design and operation of catalytic microjet engines. We show this effect on catalytic micromotors prepared by both rolled-up and electrodeposition approaches, demonstrating that such poisoning is universal for Pt catalyzed micromotors. We believe that our findings will contribute significantly to this field to develop alternative systems or catalysts for self-propulsion when practical applications in the real environment are considered. PMID:23450281

From Usability Testing to Clinical Simulations: Bringing Context into the Design and Evaluation of Usable and Safe Health Information Technologies. Contribution of the IMIA Human Factors Engineering for Healthcare Informatics Working Group.

PubMed

Kushniruk, A; Nohr, C; Jensen, S; Borycki, E M

2013-01-01

The objective of this paper is to explore human factors approaches to understanding the use of health information technology (HIT) by extending usability engineering approaches to include analysis of the impact of clinical context through use of clinical simulations. Methods discussed are considered on a continuum from traditional laboratory-based usability testing to clinical simulations. Clinical simulations can be conducted in a simulation laboratory and they can also be conducted in real-world settings. The clinical simulation approach attempts to bring the dimension of clinical context into stronger focus. This involves testing of systems with representative users doing representative tasks, in representative settings/environments. Application of methods where realistic clinical scenarios are used to drive the study of users interacting with systems under realistic conditions and settings can lead to identification of problems and issues with systems that may not be detected using traditional usability engineering methods. In conducting such studies, careful consideration is needed in creating ecologically valid test scenarios. The evidence obtained from such evaluation can be used to improve both the usability and safety of HIT. In addition, recent work has shown that clinical simulations, in particular those conducted in-situ, can lead to considerable benefits when compared to the costs of running such studies. In order to bring context of use into the testing of HIT, clinical simulation, involving observing representative users carrying out tasks in representative settings, holds considerable promise.

Interactive Media and Simulation Tools for Technical Training

NASA Technical Reports Server (NTRS)

Gramoll, Kurt

1997-01-01

Over the last several years, integration of multiple media sources into a single information system has been rapidly developing. It has been found that when sound, graphics, text, animations, and simulations are skillfully integrated, the sum of the parts exceeds the individual parts for effective learning. In addition, simulations can be used to design and understand complex engineering processes. With the recent introduction of many high-level authoring, animation, modeling, and rendering programs for personal computers, significant multimedia programs can be developed by practicing engineers, scientists and even managers for both training and education. However, even with these new tools, a considerable amount of time is required to produce an interactive multimedia program. The development of both CD-ROM and Web-based programs are discussed in addition to the use of technically oriented animations. Also examined are various multimedia development tools and how they are used to develop effective engineering education courseware. Demonstrations of actual programs in engineering mechanics are shown.

Design of Light-Controlled Protein Conformations and Functions.

PubMed

Ritterson, Ryan S; Hoersch, Daniel; Barlow, Kyle A; Kortemme, Tanja

2016-01-01

In recent years, interest in controlling protein function with light has increased. Light offers a number of unique advantages over other methods, including spatial and temporal control and high selectivity. Here, we describe a general protocol for engineering a protein to be controllable with light via reaction with an exogenously introduced photoisomerizable small molecule and illustrate our protocol with two examples from the literature: the engineering of the calcium affinity of the cell-cell adhesion protein cadherin, which is an example of a protein that switches from a native to a disrupted state (Ritterson et al. J Am Chem Soc (2013) 135:12516-12519), and the engineering of the opening and closing of the chaperonin Mm-cpn, an example of a switch between two functional states (Hoersch et al.: Nat Nanotechn (2013) 8:928-932). This protocol guides the user from considering which proteins may be most amenable to this type of engineering, to considerations of how and where to make the desired changes, to the assays required to test for functionality.

Viper cabin-fuselage structural design concept with engine installation and wing structural design

NASA Technical Reports Server (NTRS)

Marchesseault, B.; Carr, D.; Mccorkle, T.; Stevens, C.; Turner, D.

1993-01-01

This report describes the process and considerations in designing the cabin, nose, drive shaft, and wing assemblies for the 'Viper' concept aircraft. Interfaces of these assemblies, as well as interfaces with the sections of the aircraft aft of the cabin, are also discussed. The results of the design process are included. The goal of this project is to provide a structural design which complies with FAR 23 requirements regarding occupant safety, emergency landing loads, and maneuvering loads. The design must also address the interfaces of the various systems in the cabin, nose, and wing, including the drive shaft, venting, vacuum, electrical, fuel, and control systems. Interfaces between the cabin assembly and the wing carrythrough and empennage assemblies were required, as well. In the design of the wing assemblies, consistency with the existing cabin design was required. The major areas considered in this report are materials and construction, loading, maintenance, environmental considerations, wing assembly fatigue, and weight. The first three areas are developed separately for the nose, cabin, drive shaft, and wing assemblies, while the last three are discussed for the entire design. For each assembly, loading calculations were performed to determine the proper sizing of major load carrying components. Table 1.0 lists the resulting margins of safety for these key components, along with the types of the loads involved, and the page number upon which they are discussed.

Using computed tomography and 3D printing to construct custom prosthetics attachments and devices.

PubMed

Liacouras, Peter C; Sahajwalla, Divya; Beachler, Mark D; Sleeman, Todd; Ho, Vincent B; Lichtenberger, John P

2017-01-01

The prosthetic devices the military uses to restore function and mobility to our wounded warriors are highly advanced, and in many instances not publically available. There is considerable research aimed at this population of young patients who are extremely active and desire to take part in numerous complex activities. While prosthetists design and manufacture numerous devices with standard materials and limb assemblies, patients often require individualized prosthetic design and/or modifications to enable them to participate fully in complex activities. Prosthetists and engineers perform research and implement digitally designs in collaboration to generate equipment for their patient's rehabilitation needs. 3D printing allows for these devices to be manufactured from an array of materials ranging from plastic to titanium alloy. Many designs require form fitting to a prosthetic socket or a complex surface geometry. Specialty items can be scanned using computed tomography and digitally reconstructed to produce a virtual 3D model the engineer can use to design the necessary features of the desired prosthetic, device, or attachment. Completed devices are tested for fit and function. Numerous custom prostheses and attachments have been successfully translated from the research domain to clinical reality, in particular, those that feature the use of computed tomography (CT) reconstructions. The purpose of this project is to describe the research pathways to implementation for the following clinical designs: sets of bilateral hockey skates; custom weightlifting prosthetic hands; and a wine glass holder. This article will demonstrate how to incorporate CT imaging and 3D printing in the design and manufacturing process of custom attachments and assistive technology devices. Even though some of these prosthesis attachments may be relatively simple in design to an engineer, they have an enormous impact on the lives of our wounded warriors.

Basic design considerations for free-electron lasers driven by electron beams from RF accelerators

NASA Astrophysics Data System (ADS)

Gover, A.; Freund, H.; Granatstein, V. L.; McAdoo, J. H.; Tang, C.-M.

A design procedure and design criteria are derived for free-electron lasers driven by electron beams from RF accelerators. The procedure and criteria permit an estimate of the oscillation-buildup time and the laser output power of various FEL schemes: with waveguide resonator or open resonator, with initial seed-radiation injection or with spontaneous-emission radiation source, with a linear wiggler or with a helical wiggler. Expressions are derived for computing the various FEL parameters, allowing for the design and optimization of the FEL operational characteristics under ideal conditions or with nonideal design parameters that may be limited by technological or practical constraints. The design procedure enables one to derive engineering curves and scaling laws for the FEL operating parameters. This can be done most conveniently with a computer program based on flowcharts given in the appendices.

Design Life Level: Quantifying risk in a changing climate

NASA Astrophysics Data System (ADS)

Rootzén, Holger; Katz, Richard W.

2013-09-01

In the past, the concepts of return levels and return periods have been standard and important tools for engineering design. However, these concepts are based on the assumption of a stationary climate and do not apply to a changing climate, whether local or global. In this paper, we propose a refined concept, Design Life Level, which quantifies risk in a nonstationary climate and can serve as the basis for communication. In current practice, typical hydrologic risk management focuses on a standard (e.g., in terms of a high quantile corresponding to the specified probability of failure for a single year). Nevertheless, the basic information needed for engineering design should consist of (i) the design life period (e.g., the next 50 years, say 2015-2064); and (ii) the probability (e.g., 5% chance) of a hazardous event (typically, in the form of the hydrologic variable exceeding a high level) occurring during the design life period. Capturing both of these design characteristics, the Design Life Level is defined as an upper quantile (e.g., 5%) of the distribution of the maximum value of the hydrologic variable (e.g., water level) over the design life period. We relate this concept and variants of it to existing literature and illustrate how they, and some useful complementary plots, may be computed and used. One practically important consideration concerns quantifying the statistical uncertainty in estimating a high quantile under nonstationarity.

The Design of Akhmat Tower

NASA Astrophysics Data System (ADS)

Beardsley, Sara; Stochetti, Alejandro; Cerone, Marc

2018-03-01

Akhmat Tower is a 435m supertall building designed by Adrian Smith + Gordon Gill Architecture. It is currently under construction in the city of Grozny, in the Chechen Republic, in the North Caucasus region of Russia. The design of the tower was done during a collaborative process by a multi-disciplinary architectural and engineering team, based primarily in the United States and Russia. During this process, the designers considered many factors including, most primarily, the cultural and historical context, the structural requirements given the high seismicity of the region, and the client's programmatic needs. The resulting crystalline-shaped tower is both an aesthetic statement and a performative architectural solution which will be a new landmark for Chechnya. "The Design of Akhmat Tower" describes in detail the design process including structural considerations, exterior wall design, building program, interior design, the tuned mass damper, and the use of building information modeling.

Tesseract supersonic business transport

NASA Technical Reports Server (NTRS)

Reshotko, Eli; Garbinski, Gary; Fellenstein, James; Botting, Mary; Hooper, Joan; Ryan, Michael; Struk, Peter; Taggart, Ben; Taillon, Maggie; Warzynski, Gary

1992-01-01

This year, the senior level Aerospace Design class at Case Western Reserve University developed a conceptual design of a supersonic business transport. Due to the growing trade between Asia and the United States, a transpacific range was chosen for the aircraft. A Mach number of 2.2 was chosen, too, because it provides reasonable block times and allows the use of a large range of materials without a need for active cooling. A payload of 2,500 lbs. was assumed corresponding to a complement of nine passengers and crew, plus some light cargo. With these general requirements set, the class was broken down into three groups. The aerodynamics of the aircraft were the responsibility of the first group. The second developed the propulsion system. The efforts of both the aerodynamics and propulsion groups were monitored and reviewed for weight considerations and structural feasibility by the third group. Integration of the design required considerable interaction between the groups in the final stages. The fuselage length of the final conceptual design was 107.0 ft, while the diameter of the fuselage was 7.6 ft. The delta wing design consisted of an aspect ratio of 1.9 with a wing span of 47.75 ft and mid-chord length of 61.0 ft. A SNECMA MCV 99 variable-cycle engine design was chosen for this aircraft.

Tesseract: Supersonic business transport

NASA Technical Reports Server (NTRS)

Reshotko, Eli; Garbinski, Gary

1992-01-01

This year, the senior level Aerospace Design class at Case Western Reserve University developed a conceptual design of a supersonic business transport. Due to the growing trade between Asia and the United States, a transpacific range has been chosen for the aircraft. A Mach number of 2.2 was chosen too because it provides reasonable block times and allows the use of a large range of materials without a need for active cooling. A payload of 2500 lbs. has been assumed corresponding to a complement of nine (passengers and crew) plus some light cargo. With these general requirements set, the class was broken down into three groups. The aerodynamics of the aircraft were the responsibility of the first group. The second developed the propulsion system. The efforts of both the aerodynamics and propulsion groups were monitored and reviewed for weight considerations and structural feasibility by the third group. Integration of the design required considerable interaction between the groups in the final stages. The fuselage length of the final conceptual design was 107.0 ft. while the diameter of the fuselage was 7.6 ft. The delta wing design consisted of an aspect ratio of 1.9 with a wing span of 47.75 ft and midcord length of 61.0 ft. A SNEMCA MCV 99 variable-cycle engine design was chosen for this aircraft.

C-Band Airport Surface Communications System Standards Development. Phase II Final Report. Volume 1: Concepts of Use, Initial System Requirements, Architecture, and AeroMACS Design Considerations

NASA Technical Reports Server (NTRS)

Hall, Edward; Isaacs, James; Henriksen, Steve; Zelkin, Natalie

2011-01-01

This report is provided as part of ITT s NASA Glenn Research Center Aerospace Communication Systems Technical Support (ACSTS) contract NNC05CA85C, Task 7: New ATM Requirements-Future Communications, C-Band and L-Band Communications Standard Development and was based on direction provided by FAA project-level agreements for New ATM Requirements-Future Communications. Task 7 included two subtasks. Subtask 7-1 addressed C-band (5091- to 5150-MHz) airport surface data communications standards development, systems engineering, test bed and prototype development, and tests and demonstrations to establish operational capability for the Aeronautical Mobile Airport Communications System (AeroMACS). Subtask 7-2 focused on systems engineering and development support of the L-band digital aeronautical communications system (L-DACS). Subtask 7-1 consisted of two phases. Phase I included development of AeroMACS concepts of use, requirements, architecture, and initial high-level safety risk assessment. Phase II builds on Phase I results and is presented in two volumes. Volume I (this document) is devoted to concepts of use, system requirements, and architecture, including AeroMACS design considerations. Volume II describes an AeroMACS prototype evaluation and presents final AeroMACS recommendations. This report also describes airport categorization and channelization methodologies. The purposes of the airport categorization task were (1) to facilitate initial AeroMACS architecture designs and enable budgetary projections by creating a set of airport categories based on common airport characteristics and design objectives, and (2) to offer high-level guidance to potential AeroMACS technology and policy development sponsors and service providers. A channelization plan methodology was developed because a common global methodology is needed to assure seamless interoperability among diverse AeroMACS services potentially supplied by multiple service providers.

Space Transportation System Availability Requirement and Its Influencing Attributes Relationships

NASA Technical Reports Server (NTRS)

Rhodes, Russell E.; Adams, Timothy C.; McCleskey, Carey M.

2008-01-01

It is important that engineering and management accept the need for an availability requirement that is derived with its influencing attributes. It is the intent of this paper to provide the visibility of relationships of these major attribute drivers (variables) to each other and the resultant system inherent availability. Also important to provide bounds of the variables providing engineering the insight required to control the system's engineering solution, e.g., these influencing attributes become design requirements also. These variables will drive the need to provide integration of similar discipline functions or technology selection to allow control of the total parts count. The relationship of selecting a reliability requirement will place a constraint on parts count to achieve a given availability requirement or if allowed to increase the parts count will drive the system reliability requirement higher. They also provide the understanding for the relationship of mean repair time (or mean down time) to maintainability, e.g., accessibility for repair, and both the mean time between failure, e.g., reliability of hardware and availability. The concerns and importance of achieving a strong availability requirement is driven by the need for affordability, the choice of using the two launch solution for the single space application, or the need to control the spare parts count needed to support the long stay in either orbit or on the surface of the moon. Understanding the requirements before starting the architectural design concept will avoid considerable time and money required to iterate the design to meet the redesign and assessment process required to achieve the results required of the customer's space transportation system. In fact the impact to the schedule to being able to deliver the system that meets the customer's needs, goals, and objectives may cause the customer to compromise his desired operational goal and objectives resulting in considerable increased life cycle cost of the fielded space transportation system.

Space Transportation System Availability Requirements and Its Influencing Attributes Relationships

NASA Technical Reports Server (NTRS)

Rhodes, Russell E.; Adams, Timothy C.; McCleskey, Carey M.

2008-01-01

It is important that engineering and management accept the need for an availability requirement that is derived with its influencing attributes. It is the intent of this paper to provide the visibility of relationships of these major attribute drivers (variables) to each other and the resultant system inherent availability. Also important to provide bounds of the variables providing engineering the insight required to control the system's engineering solution, e.g., these influencing attributes become design requirements also. These variables will drive the need to provide integration of similar discipline functions or technology selection to allow control of the total parts count. The relationship of selecting a reliability requirement will place a constraint on parts count to achieve a given availability requirement or if allowed to increase the parts count will drive the system reliability requirement higher. They also provide the understanding for the relationship of mean repair time (or mean down time) to maintainability, e.g., accessibility for repair, and both the mean time between failure, e.g., reliability of hardware and availability. The concerns and importance of achieving a strong availability requirement is driven by the need for affordability, the choice of using the two launch solution for the single space application, or the need to control the spare parts count needed to support the long stay in either orbit or on the surface of the moon. Understanding the requirements before starting the architectural design concept will avoid considerable time and money required to iterate the design to meet the redesign and assessment process required to achieve the results required of the customer's space transportation system. In fact the impact to the schedule to being able to deliver the system that meets the customer's needs, goals, and objectives may cause the customer to compromise his desired operational goal and objectives resulting in considerable increased life cycle cost of the fielded space transportation system.

Synthetic biology and its alternatives. Descartes, Kant and the idea of engineering biological machines.

PubMed

Kogge, Werner; Richter, Michael

2013-06-01

The engineering-based approach of synthetic biology is characterized by an assumption that 'engineering by design' enables the construction of 'living machines'. These 'machines', as biological machines, are expected to display certain properties of life, such as adapting to changing environments and acting in a situated way. This paper proposes that a tension exists between the expectations placed on biological artefacts and the notion of producing such systems by means of engineering; this tension makes it seem implausible that biological systems, especially those with properties characteristic of living beings, can in fact be produced using the specific methods of engineering. We do not claim that engineering techniques have nothing to contribute to the biotechnological construction of biological artefacts. However, drawing on Descartes's and Kant's thinking on the relationship between the organism and the machine, we show that it is considerably more plausible to assume that distinctively biological artefacts emerge within a paradigm different from the paradigm of the Cartesian machine that underlies the engineering approach. We close by calling for increased attention to be paid to approaches within molecular biology and chemistry that rest on conceptions different from those of synthetic biology's engineering paradigm. Copyright © 2013 Elsevier Ltd. All rights reserved.

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.

Design Process of Flight Vehicle Structures for a Common Bulkhead and an MPCV Spacecraft Adapter

NASA Technical Reports Server (NTRS)

Aggarwal, Pravin; Hull, Patrick V.

2015-01-01

Design and manufacturing space flight vehicle structures is a skillset that has grown considerably at NASA during that last several years. Beginning with the Ares program and followed by the Space Launch System (SLS); in-house designs were produced for both the Upper Stage and the SLS Multipurpose crew vehicle (MPCV) spacecraft adapter. Specifically, critical design review (CDR) level analysis and flight production drawing were produced for the above mentioned hardware. In particular, the experience of this in-house design work led to increased manufacturing infrastructure for both Marshal Space Flight Center (MSFC) and Michoud Assembly Facility (MAF), improved skillsets in both analysis and design, and hands on experience in building and testing (MSA) full scale hardware. The hardware design and development processes from initiation to CDR and finally flight; resulted in many challenges and experiences that produced valuable lessons. This paper builds on these experiences of NASA in recent years on designing and fabricating flight hardware and examines the design/development processes used, as well as the challenges and lessons learned, i.e. from the initial design, loads estimation and mass constraints to structural optimization/affordability to release of production drawing to hardware manufacturing. While there are many documented design processes which a design engineer can follow, these unique experiences can offer insight into designing hardware in current program environments and present solutions to many of the challenges experienced by the engineering team.

Orbital transfer rocket engine technology: Advanced engine study

NASA Technical Reports Server (NTRS)

Hayden, Warren R.

1992-01-01

An advanced LOX/LH2 engine study for the use of NASA and vehicle prime contractors in developing concepts for manned missions to the Moon, Mars, and Phobos is documented. Parametric design data was obtained at five engine thrusts from 7.5K lbf to 50K lbf. Also, a separate task evaluated engine throttling over a 20:1 range and operation at a mixture ratio of 12 plus or minus 1 versus the 6 plus or minus 1 nominal. Cost data was also generated for DDT&E, first unit production, and factors in other life cycle costs. The major limitation of the study was lack of contact with vehicle prime contractors to resolve the issues in vehicle/engine interfaces. The baseline Aerojet dual propellant expander cycle was shown capable of meeting all performance requirements with an expected long operational life due to the high thermal margins. The basic engine design readily accommodated the 20:1 throttling requirement and operation up to a mixture ratio of 10 without change. By using platinum for baffled injector construction the increased thermal margin allowed operation up to mixture ratio 13. An initial engine modeling with an Aerojet transient simulation code (named MLETS) indicates stable engine operation with the baseline control system. A throttle ratio of 4 to 5 seconds from 10 percent to 100 percent thrust is also predicted. Performance predictions are 483.1 sec at 7.5K lbf, 487.3 sec at 20K lbf, and 485.2 sec at 50K lbf with a mixture ratio of 6 and an area ratio of 1200. Engine envelopes varied from 120 in. length/53 in. exit diameter at 7.5K lbf to 305 in. length/136 in. exit diameter at 50 K lbf. Packaging will be an important consideration. Continued work is recommended to include more vehicle prime contractor/engine contractor joint assessment of the interface issues.

Evaluation of an innovative high temperature ceramic wafer seal for hypersonic engine applications. Ph.D. Thesis, 1991

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M.

1992-01-01

A critical mechanical system in advanced hypersonic engines is the panel-edge seal system that seals gaps between the articulating engine panels and the adjacent engine splitter walls. Significant advancements in seal technology are required to meet the extreme demands placed on the seals, including the simultaneous requirements of low leakage, conformable, high temperature, high pressure, sliding operation. In this investigation, the design, development, analytical and experimental evaluation of a new ceramic wafer seal that shows promise of meeting these demands will be addressed. A high temperature seal test fixture was designed and fabricated to measure static seal leakage performance under engine simulated conditions. Ceramic wafer seal leakage rates are presented for engine-simulated air pressure differentials (up to 100 psi), and temperature (up to 1350 F), sealing both flat and distorted wall conditions, where distortions can be as large as 0.15 inches in only an 18 inch span. Seal leakage rates are low, meeting an industry-established tentative leakage limit for all combinations of temperature, pressure and wall conditions considered. A seal leakage model developed from externally-pressurized gas film bearing theory is also presented. Predicted leakage rates agree favorably with the measured data for nearly all conditions of temperature and pressure. Discrepancies noted at high engine pressure and temperature are attributed to thermally-induced, non-uniform changes in the size and shape of the leakage gap condition. The challenging thermal environment the seal must operate in places considerable demands on the seal concept and material selection. Of the many high temperature materials considered in the design, ceramics were the only materials that met the many challenging seal material design requirements. Of the aluminum oxide, silicon carbide, and silicon nitride ceramics considered in the material ranking scheme developed herein, the silicon nitride class of ceramics ranked the highest because of their high temperature strength; resistance to the intense heating rates; resistance to hydrogen damage; and good structural properties. Baseline seal feasibility has been established through the research conducted in this investigation. Recommendations for future work are also discussed.

FPGA implementation of predictive degradation model for engine oil lifetime

NASA Astrophysics Data System (ADS)

Idros, M. F. M.; Razak, A. H. A.; Junid, S. A. M. Al; Suliman, S. I.; Halim, A. K.

2018-03-01

This paper presents the implementation of linear regression model for degradation prediction on Register Transfer Logic (RTL) using QuartusII. A stationary model had been identified in the degradation trend for the engine oil in a vehicle in time series method. As for RTL implementation, the degradation model is written in Verilog HDL and the data input are taken at a certain time. Clock divider had been designed to support the timing sequence of input data. At every five data, a regression analysis is adapted for slope variation determination and prediction calculation. Here, only the negative value are taken as the consideration for the prediction purposes for less number of logic gate. Least Square Method is adapted to get the best linear model based on the mean values of time series data. The coded algorithm has been implemented on FPGA for validation purposes. The result shows the prediction time to change the engine oil.

Fuel-injection control of S.I. engines

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

Choi, S.B.; Won, M.; Hedrick, J.K.

1994-12-31

It is known that about 50% of air pollutants comes from automotive engine exhaust, and mostly in a transient state operation. However, the wide operating range, the inherent nonlinearities of the induction process and the large modeling uncertainties make the design of the fuel-injection controller very difficult. Also, the unavoidable large time-delay between control action and measurement causes the problem of chattering. In this paper, an observer-based control algorithm based on sliding mode control technique is suggested for fast response and small amplitude chattering of the air-to-fuel ratio. A direct adaptive control using Gaussian networks is applied to the compensationmore » of transient fueling dynamics. The proposed controller is simple enough for on-line computation and is implemented on an automotive engine using a PC-386. The simulation and the experimental results show that this algorithm reduces the chattering magnitude considerably and is robust to modeling errors.« less

Mechanical stimulation in the engineering of heart muscle.

PubMed

Liaw, Norman Yu; Zimmermann, Wolfram-Hubertus

2016-01-15

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

Through the Google Goggles: Sociopolitical Bias in Search Engine Design

NASA Astrophysics Data System (ADS)

Diaz, A.

Search engines like Google are essential to navigating the Web's endless supply of news, political information, and citizen discourse. The mechanisms and conditions under which search results are selected should therefore be of considerable interest to media scholars, political theorists, and citizens alike. In this chapter, I adopt a "deliberative" ideal for search engines and examine whether Google exhibits the "same old" media biases of mainstreaming, hypercommercialism, and industry consolidation. In the end, serious objections to Google are raised: Google may favor popularity over richness; it provides advertising that competes directly with "editorial" content; it so overwhelmingly dominates the industry that users seldom get a second opinion, and this is unlikely to change. Ultimately, however, the results of this analysis may speak less about Google than about contradictions in the deliberative ideal and the so-called "inherently democratic" nature of the Web.