WorldWideScience

Sample records for turbofan engine structural

  1. Separated core turbofan engine; Core bunrigata turbofan engine

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Y.; Endo, M.; Matsuda, Y.; Sugiyama, N.; Sugahara, N.; Yamamoto, K. [National Aerospace Laboratory, Tokyo (Japan)

    1996-04-01

    This report outlines the separated core turbofan engine. This engine is featured by parallel separated arrangement of a fan and core engine which are integrated into one unit in the conventional turbofan engine. In general, cruising efficiency improvement and noise reduction are achieved by low fan pressure ratio and low exhaust speed due to high bypass ratio, however, it causes various problems such as large fan and nacelle weight due to large air flow rate of a fan, and shift of an operating point affected by flight speed. The parallel separated arrangement is thus adopted. The stable operation of a fan and core engine is easily retained by independently operating air inlet unaffected by fan. The large degree of freedom of combustion control is also obtained by independent combustor. Fast response, simple structure and optimum aerodynamic design are easily achieved. This arrangement is also featured by flexibility of development and easy maintenance, and by various merits superior to conventional turbofan engines. It has no technological problems difficult to be overcome, and is also suitable for high-speed VTOL transport aircraft. 4 refs., 5 figs.

  2. Advanced Control of Turbofan Engines

    CERN Document Server

    Richter, Hanz

    2012-01-01

    Advanced Control of Turbofan Engines describes the operational performance requirements of turbofan (commercial)engines from a controls systems perspective, covering industry-standard methods and research-edge advances. This book allows the reader to design controllers and produce realistic simulations using public-domain software like CMAPSS: Commercial Modular Aero-Propulsion System Simulation, whose versions are released to the public by NASA. The scope of the book is centered on the design of thrust controllers for both steady flight and transient maneuvers. Classical control theory is not dwelled on, but instead an introduction to general undergraduate control techniques is provided. This book also: Develops a thorough understanding of the challenges associated with engine operability from a control systems perspective, describing performance demands and operational constraints into the framework and language of modern control theory Presents solid theoretical support for classical and advanced engine co...

  3. 78 FR 5710 - Airworthiness Directives; Engine Alliance Turbofan Engines

    Science.gov (United States)

    2013-01-28

    ..., an ``engine shop visit'' is the induction of an engine into the shop for maintenance involving the... Airworthiness Directives; Engine Alliance Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT... all Engine Alliance GP7270 and GP7277 turbofan engines. This AD requires initial and repetitive...

  4. Windmilling of turbofan engine; calculation of performance characteristics of a turbofan engine under windmilling

    NARCIS (Netherlands)

    Ramanathan, A.

    2014-01-01

    The turbofan is a type of air breathing jet engine that finds wide use in aircraft propulsion. During the normal operation of a turbofan engine installed in aircraft, the combustor is supplied with fuel, flow to the combustor is cut off and the engine runs under so called Windmilling conditions

  5. 78 FR 38195 - Airworthiness Directives; General Electric Company Turbofan Engines

    Science.gov (United States)

    2013-06-26

    ... Directives; General Electric Company Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT... all General Electric Company (GE) GE90-110B1 and GE90-115B turbofan engines. This emergency AD was...) Applicability General Electric Company (GE) GE90-110B1 and GE90-115B turbofan engines with a transfer gearbox...

  6. 78 FR 72552 - Airworthiness Directives; General Electric Company Turbofan Engines

    Science.gov (United States)

    2013-12-03

    ... Airworthiness Directives; General Electric Company Turbofan Engines AGENCY: Federal Aviation Administration (FAA... General Electric Company model GEnx-2B67 and GEnx-2B67B turbofan engines. This AD was prompted by the... certain serial number General Electric Company (GE) model GEnx-2B67 and GEnx-2B67B turbofan engines. The...

  7. 77 FR 48110 - Airworthiness Directives; General Electric Company Turbofan Engines

    Science.gov (United States)

    2012-08-13

    ... engine shop visit is defined as the induction of an engine into the shop for any reason. (h) Prohibition... Company Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed... certain General Electric Company (GE) CF6-80C2 series turbofan engines. The existing AD requires...

  8. 76 FR 64844 - Airworthiness Directives; General Electric Company Turbofan Engines

    Science.gov (United States)

    2011-10-19

    ...) For the purposes of this AD, an engine shop visit is the induction of an engine into the shop after... Company Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed... General Electric Company (GE) CF6-45 and CF6-50 series turbofan engines with certain low-pressure turbine...

  9. 78 FR 76045 - Airworthiness Directives; General Electric Company Turbofan Engines

    Science.gov (United States)

    2013-12-16

    ... Airworthiness Directives; General Electric Company Turbofan Engines AGENCY: Federal Aviation Administration (FAA... (AD) for General Electric Company (GE) GE90-110B1 and GE90-115B turbofan engines with certain high... rotating engine part, which could result in an uncontained engine failure and damage to the airplane. DATES...

  10. 78 FR 47534 - Airworthiness Directives; General Electric Company Turbofan Engines

    Science.gov (United States)

    2013-08-06

    ... Airworthiness Directives; General Electric Company Turbofan Engines AGENCY: Federal Aviation Administration (FAA... directive (AD) 2013-14-51 for General Electric Company (GE) GE90-110B1 and GE90-115B turbofan engines with... all known U.S. owners and operators of GE90-110B1 and GE90-115B turbofan engines. AD 2013-14-51...

  11. Advanced Control Considerations for Turbofan Engine Design

    Science.gov (United States)

    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.

  12. 78 FR 72567 - Airworthiness Directives; General Electric Company Turbofan Engines

    Science.gov (United States)

    2013-12-03

    ...) Definition For the purpose of this AD, a shop visit is the induction of an engine into the shop for... Airworthiness Directives; General Electric Company Turbofan Engines AGENCY: Federal Aviation Administration (FAA... General Electric Company (GE) GE90-110B1 and -115B turbofan engines. This AD was prompted by multiple...

  13. 77 FR 3088 - Airworthiness Directives; General Electric Company Turbofan Engines

    Science.gov (United States)

    2012-01-23

    ... Airworthiness Directives; General Electric Company Turbofan Engines AGENCY: Federal Aviation Administration (FAA... Electric Company (GE) CF34-10E series turbofan engines. This AD was prompted by a report of heavy wear... removing from service all CVD support assemblies and any fan drive shaft on the affected engines if wear is...

  14. 78 FR 56594 - Airworthiness Directives; General Electric Company Turbofan Engines

    Science.gov (United States)

    2013-09-13

    ... Airworthiness Directives; General Electric Company Turbofan Engines AGENCY: Federal Aviation Administration (FAA... General Electric Company (GE) GE90-76B, -85B, -90B, -94B, -110B1, and - 115B turbofan engines. This AD was... to accelerated corrosion and oxidation, including one engine in- flight shutdown (IFSD) caused by...

  15. 78 FR 19983 - Airworthiness Directives; General Electric Company Turbofan Engines

    Science.gov (United States)

    2013-04-03

    ... Airworthiness Directives; General Electric Company Turbofan Engines AGENCY: Federal Aviation Administration (FAA... Electric Company (GE) CF34-8C and CF34-8E turbofan engines with certain part numbers (P/N) of operability... the OBV. Two of those events led to an engine fire. This AD requires the affected OBVs be removed from...

  16. 78 FR 19628 - Airworthiness Directives; General Electric Company Turbofan Engines

    Science.gov (United States)

    2013-04-02

    ... Electric Company (GE) GE90-76B, -85B, -90B, -94B, - 110B1, and -115B turbofan engines. This proposed AD was...-0186; Directorate Identifier 2013-NE-11-AD] RIN 2120-AA64 Airworthiness Directives; General Electric Company Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed...

  17. 76 FR 72348 - Airworthiness Directives; Pratt & Whitney Turbofan Engines

    Science.gov (United States)

    2011-11-23

    ... engine shop visit is the induction of an engine into the shop after the effective date of this AD, where... Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed rulemaking..., -7R4D1, -7R4E, -7R4E1, -7R4G2, -7R4H1, and - 7R4E4 turbofan engines. This proposed AD would establish a...

  18. CLASSIFICATION OF NEURAL NETWORK FOR TECHNICAL CONDITION OF TURBOFAN ENGINES BASED ON HYBRID ALGORITHM

    Directory of Open Access Journals (Sweden)

    Valentin Potapov

    2016-12-01

    Full Text Available Purpose: This work presents a method of diagnosing the technical condition of turbofan engines using hybrid neural network algorithm based on software developed for the analysis of data obtained in the aircraft life. Methods: allows the engine diagnostics with deep recognition to the structural assembly in the presence of single structural damage components of the engine running and the multifaceted damage. Results: of the optimization of neural network structure to solve the problems of evaluating technical state of the bypass turbofan engine, when used with genetic algorithms.

  19. 77 FR 58471 - Airworthiness Directives; General Electric Company Turbofan Engines

    Science.gov (United States)

    2012-09-21

    ... Airworthiness Directives; General Electric Company Turbofan Engines AGENCY: Federal Aviation Administration (FAA... (AD) for General Electric Company GEnx-1B54, GEnx-1B58, GEnx-1B64, GEnx-1B67, GEnx-1B70, GEnx-1B54/P1.../P1, GEnx-1B75/P1, GEnx- 2B67, and GEnx-2B67B turbofan engines. This AD requires initial and...

  20. Kalman Filtering with Inequality Constraints for Turbofan Engine Health Estimation

    Science.gov (United States)

    Simon, Dan; Simon, Donald L.

    2003-01-01

    Kalman filters are often used to estimate the state variables of a dynamic system. However, in the application of Kalman filters some known signal information is often either ignored or dealt with heuristically. For instance, state variable constraints (which may be based on physical considerations) are often neglected because they do not fit easily into the structure of the Kalman filter. This paper develops two analytic methods of incorporating state variable inequality constraints in the Kalman filter. The first method is a general technique of using hard constraints to enforce inequalities on the state variable estimates. The resultant filter is a combination of a standard Kalman filter and a quadratic programming problem. The second method uses soft constraints to estimate state variables that are known to vary slowly with time. (Soft constraints are constraints that are required to be approximately satisfied rather than exactly satisfied.) The incorporation of state variable constraints increases the computational effort of the filter but significantly improves its estimation accuracy. The improvement is proven theoretically and shown via simulation results. The use of the algorithm is demonstrated on a linearized simulation of a turbofan engine to estimate health parameters. The turbofan engine model contains 16 state variables, 12 measurements, and 8 component health parameters. It is shown that the new algorithms provide improved performance in this example over unconstrained Kalman filtering.

  1. 78 FR 21578 - Airworthiness Directives; General Electric Company Turbofan Engines

    Science.gov (United States)

    2013-04-11

    ... Company (GE) model GEnx-2B67 and GEnx-2B67B turbofan engines with booster anti-ice (BAI) air duct, part... reports of cracks in the BAI air duct. This proposed AD would require initial and repetitive visual inspections of the BAI air duct, removal from service of the BAI air duct if it fails inspection and, as a...

  2. 78 FR 50320 - Airworthiness Directives; General Electric Company Turbofan Engines

    Science.gov (United States)

    2013-08-19

    ... Electric Company (GE) model GEnx-2B67B turbofan engines with booster anti-ice (BAI) air duct, part number... cracks in the BAI air duct. This AD requires initial and repetitive visual inspections of the BAI air duct, removal from service of the BAI air duct if it fails inspection and, as a mandatory terminating...

  3. 77 FR 74125 - Airworthiness Directives; General Electric Company Turbofan Engines

    Science.gov (United States)

    2012-12-13

    ...-1288; Directorate Identifier 2012-NE-37-AD] RIN 2120-AA64 Airworthiness Directives; General Electric Company Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed rulemaking (NPRM). SUMMARY: We propose to adopt a new airworthiness directive (AD) for all General Electric...

  4. 78 FR 6749 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2013-01-31

    ... FURTHER INFORMATION CONTACT: Robert Green, Aerospace Engineer, Engine Certification Office, FAA, Engine... more information about this AD, contact Robert Green, Aerospace Engineer, Engine Certification Office... Directives; Rolls-Royce plc Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION...

  5. 78 FR 61171 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2013-10-03

    ... INFORMATION CONTACT: Robert Green, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller... Information (1) For more information about this AD, contact Robert Green, Aerospace Engineer, Engine... Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: We are...

  6. 78 FR 20509 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2013-04-05

    ... CONTACT: Robert Green, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller... Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed rulemaking...) RB211-535E4-B-37 series turbofan engines. This proposed AD was prompted by recalculating the life of...

  7. 75 FR 16655 - Airworthiness Directives; Rolls-Royce plc RB211-Trent 700 Series Turbofan Engines

    Science.gov (United States)

    2010-04-02

    .... Definition (l) For the purpose of this AD, an engine shop visit is induction of the engine into the engine... Airworthiness Directives; Rolls-Royce plc RB211-Trent 700 Series Turbofan Engines AGENCY: Federal Aviation... existing airworthiness directive (AD) for Rolls-Royce plc RB211-Trent 700 series turbofan engines. That AD...

  8. 76 FR 64291 - Airworthiness Directives; General Electric Company (GE) Turbofan Engines

    Science.gov (United States)

    2011-10-18

    ... induction of an engine into the shop after the effective date of this AD, where the separation of a major... Company (GE) Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of... turbofan engines, including engines marked on the engine data plate as CF6-80C2B7F1. This proposed AD was...

  9. System Noise Prediction of the DGEN 380 Turbofan Engine

    Science.gov (United States)

    Berton, Jeffrey J.

    2015-01-01

    The DGEN 380 is a small, separate-flow, geared turbofan. Its manufacturer, Price Induction, is promoting it for a small twinjet application in the emerging personal light jet market. Smaller, and producing less thrust than other entries in the industry, Price Induction is seeking to apply the engine to a 4- to 5-place twinjet designed to compete in an area currently dominated by propeller-driven airplanes. NASA is considering purchasing a DGEN 380 turbofan to test new propulsion noise reduction technologies in a relevant engine environment. To explore this possibility, NASA and Price Induction have signed a Space Act Agreement and have agreed to cooperate on engine acoustic testing. Static acoustic measurements of the engine were made by NASA researchers during July, 2014 at the Glenn Research Center. In the event that a DGEN turbofan becomes a NASA noise technology research testbed, it is in the interest of NASA to develop procedures to evaluate engine system noise metrics. This report documents the procedures used to project the DGEN static noise measurements to flight conditions and the prediction of system noise of a notional airplane powered by twin DGEN engines.

  10. 78 FR 5126 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2013-01-24

    ... Information (1) For more information about this AD, contact Robert Green, Aerospace Engineer, Engine... Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule; request for...-Trent 970-84, 970B-84, 972-84, 972B-84, 977- 84, 977B-84, and 980-84 turbofan engines. This AD requires...

  11. 78 FR 11976 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2013-02-21

    ... after receipt. FOR FURTHER INFORMATION CONTACT: Robert Green, Aerospace Engineer, Engine Certification... plc Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule; request... plc (RR) RB211-524 series turbofan engines. That AD currently requires removal and repair of certain...

  12. 78 FR 6206 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2013-01-30

    ... receipt. FOR FURTHER INFORMATION CONTACT: Robert Green, Aerospace Engineer, Engine Certification Office... Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule; request for... 977B-84 and RB211-Trent 980-84 turbofan engines. This AD requires on-wing inspections of low-pressure...

  13. 78 FR 68360 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2013-11-14

    ..., DC 20590. FOR FURTHER INFORMATION CONTACT: Robert Green, Aerospace Engineer, Engine Certification... Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule; correction.... That AD applies to all Rolls-Royce plc (RR) RB211-535E4-B-37 series turbofan engines. The AD number is...

  14. 77 FR 16916 - Airworthiness Directives; Pratt & Whitney (PW)Turbofan Engines

    Science.gov (United States)

    2012-03-23

    ... the purposes of this AD, an engine shop visit is the induction of an engine into the shop after the... Airworthiness Directives; Pratt & Whitney (PW)Turbofan Engines AGENCY: Federal Aviation Administration (FAA... and -7R4H1 turbofan engines. This AD was prompted by the determination that a new lower life limit for...

  15. Kalman Filter Constraint Tuning for Turbofan Engine Health Estimation

    Science.gov (United States)

    Simon, Dan; Simon, Donald L.

    2005-01-01

    Kalman filters are often used to estimate the state variables of a dynamic system. However, in the application of Kalman filters some known signal information is often either ignored or dealt with heuristically. For instance, state variable constraints are often neglected because they do not fit easily into the structure of the Kalman filter. Recently published work has shown a new method for incorporating state variable inequality constraints in the Kalman filter, which has been shown to generally improve the filter s estimation accuracy. However, the incorporation of inequality constraints poses some risk to the estimation accuracy as the Kalman filter is theoretically optimal. This paper proposes a way to tune the filter constraints so that the state estimates follow the unconstrained (theoretically optimal) filter when the confidence in the unconstrained filter is high. When confidence in the unconstrained filter is not so high, then we use our heuristic knowledge to constrain the state estimates. The confidence measure is based on the agreement of measurement residuals with their theoretical values. The algorithm is demonstrated on a linearized simulation of a turbofan engine to estimate engine health.

  16. 77 FR 39157 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2012-07-02

    ... visit is the induction of an engine into the shop for maintenance involving the separation of pairs of... Airworthiness Directives; Rolls-Royce plc Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT...-84, and 980-84 turbofan engines. That AD currently requires inspecting the intermediate-pressure (IP...

  17. 78 FR 17297 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2013-03-21

    ... installation. (f) Definitions For the purpose of this AD, a shop visit is the induction of an engine into the... Airworthiness Directives; Rolls-Royce plc Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT... (AD) for all Rolls-Royce plc (RR) RB211 Trent 500 series turbofan engines. That AD currently requires...

  18. Enhanced Fan Noise Modeling for Turbofan Engines

    Science.gov (United States)

    Krejsa, Eugene A.; Stone, James R.

    2014-01-01

    This report describes work by consultants to Diversitech Inc. for the NASA Glenn Research Center (GRC) to revise the fan noise prediction procedure based on fan noise data obtained in the 9- by 15 Foot Low-Speed Wind Tunnel at GRC. The purpose of this task is to begin development of an enhanced, analytical, more physics-based, fan noise prediction method applicable to commercial turbofan propulsion systems. The method is to be suitable for programming into a computational model for eventual incorporation into NASA's current aircraft system noise prediction computer codes. The scope of this task is in alignment with the mission of the Propulsion 21 research effort conducted by the coalition of NASA, state government, industry, and academia to develop aeropropulsion technologies. A model for fan noise prediction was developed based on measured noise levels for the R4 rotor with several outlet guide vane variations and three fan exhaust areas. The model predicts the complete fan noise spectrum, including broadband noise, tones, and for supersonic tip speeds, combination tones. Both spectra and directivity are predicted. Good agreement with data was achieved for all fan geometries. Comparisons with data from a second fan, the ADP fan, also showed good agreement.

  19. Turbofan gas turbine engine with variable fan outlet guide vanes

    Science.gov (United States)

    Wood, Peter John (Inventor); Zenon, Ruby Lasandra (Inventor); LaChapelle, Donald George (Inventor); Mielke, Mark Joseph (Inventor); Grant, Carl (Inventor)

    2010-01-01

    A turbofan gas turbine engine includes a forward fan section with a row of fan rotor blades, a core engine, and a fan bypass duct downstream of the forward fan section and radially outwardly of the core engine. The forward fan section has only a single stage of variable fan guide vanes which are variable fan outlet guide vanes downstream of the forward fan rotor blades. An exemplary embodiment of the engine includes an afterburner downstream of the fan bypass duct between the core engine and an exhaust nozzle. The variable fan outlet guide vanes are operable to pivot from a nominal OGV position at take-off to an open OGV position at a high flight Mach Number which may be in a range of between about 2.5-4+. Struts extend radially across a radially inwardly curved portion of a flowpath of the engine between the forward fan section and the core engine.

  20. 77 FR 67582 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines

    Science.gov (United States)

    2012-11-13

    ... Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines AGENCY: Federal Aviation... airworthiness directive (AD) for certain Rolls-Royce Deutschland Ltd & Co KG (RRD) Tay 611-8 turbofan engines... service information identified in this proposed AD, contact Rolls-Royce Deutschland Ltd & Co KG, Eschenweg...

  1. 77 FR 66771 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines

    Science.gov (United States)

    2012-11-07

    ... Deutschland Ltd & Co KG Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of... Rolls-Royce Deutschland Ltd & Co KG (RRD) BR700-710 series turbofan engines. This proposed AD was... Deutschland Ltd & Co KG, Eschenweg 11, Dahlewitz, 15827 Blankenfelde-Mahlow, Germany; telephone: 49 0 33-7086...

  2. 78 FR 17075 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines

    Science.gov (United States)

    2013-03-20

    ... Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines AGENCY: Federal Aviation... certain Rolls-Royce Deutschland Ltd & Co KG (RRD) Tay 611-8 turbofan engines. This AD requires inspection... Rolls-Royce Deutschland Ltd & Co KG: Amendment 39-17391; Docket No. FAA-2012-1031; Directorate...

  3. 78 FR 35752 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines

    Science.gov (United States)

    2013-06-14

    ... Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines AGENCY: Federal Aviation... directive (AD) for all Rolls-Royce Deutschland Ltd & Co KG (RRD) BR700-725A1-12 turbofan engines with fuel..., contact Rolls-Royce Deutschland Ltd & Co KG, Eschenweg 11, Dahlewitz, 15827 Blankenfelde-Mahlow, Germany...

  4. 77 FR 68714 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines

    Science.gov (United States)

    2012-11-16

    ... Deutschland Ltd & Co KG Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of...-Royce Deutschland Ltd & Co KG (RRD) BR700-710A1-10 and BR700- 710A2-20 turbofan engines, and certain.... For service information identified in this proposed AD, contact Rolls-Royce Deutschland Ltd & Co KG...

  5. 78 FR 17079 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines

    Science.gov (United States)

    2013-03-20

    ... Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines AGENCY: Federal Aviation... certain Rolls-Royce Deutschland Ltd & Co KG (RRD) models Tay 620-15 and Tay 650-15 turbofan engines. This... Rolls-Royce Deutschland Ltd & Co KG (RRD) (formerly Rolls-Royce plc): Docket No. FAA-2012-1167...

  6. 78 FR 59291 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co. KG Turbofan Engines

    Science.gov (United States)

    2013-09-26

    ... Deutschland Ltd & Co. KG Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice... Rolls-Royce Deutschland Ltd & Co. KG (RRD) Tay 620-15, 650-15, and 651- 54 turbofan engines. This... information identified in this proposed AD, contact Rolls-Royce Deutschland Ltd & Co KG, Eschenweg 11...

  7. 77 FR 74123 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines

    Science.gov (United States)

    2012-12-13

    ... Deutschland Ltd & Co KG Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of... Rolls-Royce Deutschland Ltd & Co KG (RRD) models Tay 620-15 and Tay 650-15 turbofan engines. This... Deutschland Ltd & Co KG, Eschenweg 11-15827 Dahlewitz, Blankenfelde-Mahlow, Germany; phone: +49 0 33-7086-1944...

  8. 78 FR 70198 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines

    Science.gov (United States)

    2013-11-25

    ... Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines AGENCY: Federal Aviation... all Rolls-Royce Deutschland Ltd & Co KG (RRD) model Tay 620-15, 650-15, and 651-54 turbofan engines... directive (AD): 2013-23-01 Rolls-Royce Deutschland Ltd & Co KG: Amendment 39-17656; Docket No. FAA-2013-0397...

  9. 78 FR 35574 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines

    Science.gov (United States)

    2013-06-13

    ... Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines AGENCY: Federal Aviation... airworthiness directive (AD) for all Rolls-Royce Deutschland Ltd & Co KG (RRD) model Tay 650-15 turbofan engines... proposed AD, contact Rolls-Royce Deutschland Ltd & Co KG, Eschenweg 11, Dahlewitz, 15827 Blankenfelde...

  10. 78 FR 17080 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines

    Science.gov (United States)

    2013-03-20

    ... Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines AGENCY: Federal Aviation... certain Rolls-Royce Deutschland Ltd & Co KG (RRD) BR700-710 series turbofan engines. This AD requires... Rolls-Royce Deutschland Ltd & Co KG (Formerly Rolls-Royce Deutschland GmbH, and BMW Rolls-Royce plc...

  11. 76 FR 64287 - Airworthiness Directives; General Electric Company CF34-10E Series Turbofan Engines

    Science.gov (United States)

    2011-10-18

    ... General Electric Company (GE) CF34-10E series turbofan engines. This proposed AD was [[Page 64288...) Applicability This AD applies to General Electric Company (GE) CF34-10E series turbofan engines, serial number...-0599; Directorate Identifier 2011-NE-19-AD] RIN 2120-AA64 Airworthiness Directives; General Electric...

  12. 75 FR 77570 - Airworthiness Directives; General Electric Company CF6 Series Turbofan Engines

    Science.gov (United States)

    2010-12-13

    ...) for General Electric (GE) CF6-45/-50 series and CF6-80A series turbofan engines with certain part...-1151; Directorate Identifier 95-ANE-10-AD] RIN 2120-AA64 Airworthiness Directives; General Electric Company CF6 Series Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of...

  13. 78 FR 71532 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines

    Science.gov (United States)

    2013-11-29

    ... Deutschland Ltd & Co KG Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. [[Page 71533... (AD) 2007-03- 02 for all Rolls-Royce Deutschland (RRD) Tay 620-15, Tay 650-15, and Tay 651-54 turbofan... AD, contact Rolls-Royce Deutschland Ltd & Co KG, Eschenweg 11, D-15827 Blankenfelde-Mahlow, Germany...

  14. 78 FR 20505 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2013-04-05

    ... induction of an engine into the shop for maintenance or overhaul. The separation of engine flanges solely... Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed rulemaking...; - 535E4-37; -535E4-B-37, and -535E4-B-75 turbofan engines, and all RB211- 524G2-19; -524G3-19; -524H2-19...

  15. 78 FR 47235 - Airworthiness Directives; General Electric Company Turbofan Engines

    Science.gov (United States)

    2013-08-05

    ...We propose to adopt a new airworthiness directive (AD) for certain General Electric Company (GE) model GEnx-2B67 and GEnx-2B67B turbofan engines. This proposed AD was prompted by the original equipment manufacturer's disclosure that certain critical rotating life-limited parts (LLPs) used in Boeing 747-8 flight tests had consumed more cyclic life than they would have in revenue flight cycles. These parts were then installed into engines and introduced into revenue service without adjustment to remaining cyclic life. This proposed AD would require a one-time adjustment to the cycle counts of those LLPs to account for the additional low cycle fatigue (LCF) life consumed during flight tests. We are proposing this AD to prevent the failure of critical rotating LLPs, uncontained engine failure, and damage to the airplane.

  16. Research on performance requirements of turbofan engine used on carrier-based UAV

    Science.gov (United States)

    Zhao, Shufan; Li, Benwei; Zhang, Wenlong; Wu, Heng; Feng, Tang

    2017-05-01

    According to the mission requirements of the carrier-based unmanned aerial vehicle (UAV), a mode level flight was established to calculate the thrust requirements from altitude 9 km to 13 km. Then, the estimation method of flight profile was used to calculate the weight of UAV in each stage to get the specific fuel consumption requirements of the UAV in standby stage. The turbofan engine of carrier-based UAV should meet the thrust and specific fuel consumption requirements. Finally, the GSP software was used to verify the simulation of a small high-bypass turbofan engine. The conclusion is useful for the turbofan engine selection of carrier-based UAV.

  17. 78 FR 54152 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2013-09-03

    ... For the purpose of this AD, a shop visit is the induction of an engine into the shop for maintenance... Airworthiness Directives; Rolls-Royce plc Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT...; -535C-37; -535E4-37; - 535E4-B-37, and -535E4-B-75 turbofan engines, and all RB211-524G2-19; - 524G3-19...

  18. 78 FR 77382 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines

    Science.gov (United States)

    2013-12-23

    ... shop visit'' is the induction of an engine into the shop for maintenance involving the separation of... Deutschland Ltd & Co KG Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of...-Royce Deutschland Ltd & Co KG (RRD) BR700-715A1-30, BR700-715B1- 30, and BR700-715C1-30 turbofan engines...

  19. 78 FR 10501 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines

    Science.gov (United States)

    2013-02-14

    ... Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines AGENCY: Federal Aviation... all Rolls-Royce Deutschland Ltd & Co KG (RRD) BR700-710A1-10 and BR700- 710A2-20 turbofan engines, and... [Amended] 0 2. The FAA amends Sec. 39.13 by adding the following new AD: 2013-03-17 Rolls-Royce Deutschland...

  20. 76 FR 14796 - Airworthiness Directives; General Electric Company CF6-45 and CF6-50 Series Turbofan Engines

    Science.gov (United States)

    2011-03-18

    ... Airworthiness Directives; General Electric Company CF6-45 and CF6-50 Series Turbofan Engines AGENCY: Federal... airworthiness directive (AD) for General Electric Company (GE) CF6-45 and CF6-50 series turbofan engines. That... the LFCEN assembly from separating from the engine, causing damage to the engine, and damage to the...

  1. Energy Efficient Engine program advanced turbofan nacelle definition study

    Science.gov (United States)

    Howe, David C.; Wynosky, T. A.

    1985-01-01

    Advanced, low drag, nacelle configurations were defined for some of the more promising propulsion systems identified in the earlier Benefit/Cost Study, to assess the benefits associated with these advanced technology nacelles and formulate programs for developing these nacelles and low volume thrust reversers/spoilers to a state of technology readiness in the early 1990's. The study results established the design feasibility of advanced technology, slim line nacelles applicable to advanced technology, high bypass ratio turbofan engines. Design feasibility was also established for two low volume thrust reverse/spoiler concepts that meet or exceed the required effectiveness for these engines. These nacelle and thrust reverse/spoiler designs were shown to be applicable in engines with takeoff thrust sizes ranging from 24,000 to 60,000 pounds. The reduced weight, drag, and cost of the advanced technology nacelle installations relative to current technology nacelles offer a mission fuel burn savings ranging from 3.0 to 4.5 percent and direct operating cost plus interest improvements from 1.6 to 2.2 percent.

  2. 77 FR 11019 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines

    Science.gov (United States)

    2012-02-24

    ... Deutschland Ltd & Co KG Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of... Rolls-Royce Deutschland Ltd & Co KG (RRD) BR700-715A1-30, BR700-715B1-30, and BR700-715C1-30 turbofan... information identified in this proposed AD, contact Rolls-Royce Deutschland Ltd & Co KG, Eschenweg 11...

  3. 75 FR 32649 - Airworthiness Directives; General Electric Company CF6-45 and CF6-50 Series Turbofan Engines

    Science.gov (United States)

    2010-06-09

    ... Directives; General Electric Company CF6-45 and CF6-50 Series Turbofan Engines AGENCY: Federal Aviation... airworthiness directive (AD) for General Electric Company (GE) CF6-45 and CF6-50 series turbofan engines with... issuing this AD to prevent critical life-limited rotating engine part failure, which could result in an...

  4. 77 FR 13485 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2012-03-07

    ..., the term shop visit means the induction of an engine into the shop for maintenance where the front... the induction of an engine into the shop for maintenance where the front combustion liner is exposed... Airworthiness Directives; Rolls-Royce plc Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT...

  5. 76 FR 68634 - Airworthiness Directives; General Electric Company (GE) CF6 Turbofan Engines

    Science.gov (United States)

    2011-11-07

    ... Airworthiness Directives; General Electric Company (GE) CF6 Turbofan Engines AGENCY: Federal Aviation... (AD) for the engines identified above. That AD currently requires initial and repetitive visual inspections of the forward engine mount assembly side links for cracks, stripping and reapplying the Sermetel...

  6. Spectral Separation of the Turbofan Engine Coherent Combustion Noise Component

    Science.gov (United States)

    Miles, Jeffrey Hilton

    2008-01-01

    The core noise components of a dual spool turbofan engine (Honeywell TECH977) were separated by the use of a coherence function. A source location technique based on adjusting the time delay between the combustor pressure sensor signal and the far-field microphone signal to maximize the coherence and remove as much variation of the phase angle with frequency as possible was used. While adjusting the time delay to maximize the coherence and minimize the cross spectrum phase angle variation with frequency, the discovery was made that for the 130 microphone a 90.027 ms time shift worked best for the frequency band from 0 to 200 Hz while a 86.975 ms time shift worked best for the frequency band from 200 to 400 Hz. Since the 0 to 200 Hz band signal took more time to travel the same distance, it is slower than the 200 to 400 Hz band signal. This suggests the 0 to 200 Hz coherent cross spectral density band is partly due to indirect combustion noise attributed to hot spots interacting with the turbine. The signal in the 200 to 400 Hz frequency band is attributed mostly to direct combustion noise.

  7. System Would Detect Foreign-Object Damage in Turbofan Engine

    Science.gov (United States)

    Torso, James A.; Litt, Jonathan S.

    2006-01-01

    A proposed data-fusion system, to be implemented mostly in software, would further process the digitized and preprocessed outputs of sensors in a turbofan engine to detect foreign-object damage (FOD) [more precisely, damage caused by impingement of such foreign objects as birds, pieces of ice, and runway debris]. The proposed system could help a flight crew to decide what, if any, response is necessary to complete a flight safely, and could aid mechanics in deciding what post-flight maintenance action might be needed. The sensory information to be utilized by the proposed system would consist of (1) the output of an accelerometer in an engine-vibration-monitoring subsystem and (2) features extracted from a gas path analysis. ["Gas path analysis" (GPA) is a term of art that denotes comprehensive analysis of engine performance derived from readings of fuel-flow meters, shaft-speed sensors, temperature sensors, and the like.] The acceleration signal would first be processed by a wavelet-transform-based algorithm, using a wavelet created for the specific purpose of finding abrupt FOD-induced changes in noisy accelerometer signals. Two additional features extracted would be the amplitude of vibration (determined via a single- frequency Fourier transform calculated at the rotational speed of the engine), and the rate of change in amplitude due to an FOD-induced rotor imbalance. This system would utilize two GPA features: the fan efficiency and the rate of change of fan efficiency with time. The selected GPA and vibrational features would be assessed by two fuzzy-logic inference engines, denoted the "Gas Path Expert" and the "Vibration Expert," respectively (see Figure 1). Each of these inference engines would generate a "possibility" distribution for occurrence of an FOD event: Each inference engine would assign, to its input information, degrees of membership, which would subsequently be transformed into basic probability assignments for the gas path and vibration

  8. 75 FR 12661 - Airworthiness Directives; General Electric Company CF6-45 and CF6-50 Series Turbofan Engines

    Science.gov (United States)

    2010-03-17

    ... Airworthiness Directives; General Electric Company CF6-45 and CF6-50 Series Turbofan Engines AGENCY: Federal... a new airworthiness directive (AD) for General Electric Company (GE) CF6-45 and CF6-50 series turbofan engines with certain low-pressure turbine (LPT) stage 3 disks installed. This AD requires...

  9. 76 FR 6323 - Airworthiness Directives; General Electric Company CF6-45 and CF6-50 Series Turbofan Engines

    Science.gov (United States)

    2011-02-04

    ... Airworthiness Directives; General Electric Company CF6-45 and CF6-50 Series Turbofan Engines AGENCY: Federal... an existing airworthiness directive (AD) for General Electric Company (GE) CF6-45 and CF6-50 series turbofan engines with certain low-pressure turbine (LPT) rotor stage 3 disks installed. That AD currently...

  10. 77 FR 75831 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2012-12-26

    ...We are adopting a new airworthiness directive (AD) for certain serial numbers (S/Ns) of Rolls-Royce plc (RR) RB211-Trent 768-60, 772- 60, and 772B-60 turbofan engines. This AD requires initial and repetitive on-wing or in-shop inspections of the high pressure/ intermediate pressure (HP/IP) turbine bearing support oil feed tube outer heat shield. This AD also requires installation of a revised HP/ IP turbine bearing support structure as terminating action to the repetitive inspections of the HP/IP turbine bearing support oil feed tube outer heat shield. This AD was prompted by a report of high oil consumption due to an oil leak from the HP/IP turbine bearing support oil feed tube. We are issuing this AD to prevent failure of the HP turbine disc, uncontained engine failure, and damage to the airplane.

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

    Science.gov (United States)

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

    2016-01-01

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

  12. Certain Type Turbofan Engine Whole Vibration Model with Support Looseness Fault and Casing Response Characteristics

    Directory of Open Access Journals (Sweden)

    H. F. Wang

    2014-01-01

    Full Text Available Support looseness fault is a type of common fault in aeroengine. Serious looseness fault would emerge under larger unbalanced force, which would cause excessive vibration and even lead to rubbing fault, so it is important to analyze and recognize looseness fault effectively. In this paper, based on certain type turbofan engine structural features, a rotor-support-casing whole model for certain type turbofan aeroengine is established. The rotor and casing systems are modeled by means of the finite element beam method; the support systems are modeled by lumped-mass model; the support looseness fault model is also introduced. The coupled system response is obtained by numerical integral method. In this paper, based on the casing acceleration signals, the impact characteristics of symmetrical stiffness and asymmetric stiffness models are analyzed, finding that the looseness fault would lead to the longitudinal asymmetrical characteristics of acceleration time domain wave and the multiple frequency characteristics, which is consistent with the real trial running vibration signals. Asymmetric stiffness looseness model is verified to be fit for aeroengine looseness fault model.

  13. 76 FR 47056 - Airworthiness Directives; Pratt & Whitney (PW) Models PW4074 and PW4077 Turbofan Engines

    Science.gov (United States)

    2011-08-04

    ... Airworthiness Directives; Pratt & Whitney (PW) Models PW4074 and PW4077 Turbofan Engines AGENCY: Federal... AD using a drawdown plan that includes a borescope inspection (BSI) or eddy current inspection (ECI... result in a failure of the 15th stage HPC disk, uncontained engine failure, and damage to the airplane...

  14. Estimation of Signal Coherence Threshold and Concealed Spectral Lines Applied to Detection of Turbofan Engine Combustion Noise

    Science.gov (United States)

    Miles, Jeffrey Hilton

    2010-01-01

    Combustion noise from turbofan engines has become important, as the noise from sources like the fan and jet are reduced. An aligned and un-aligned coherence technique has been developed to determine a threshold level for the coherence and thereby help to separate the coherent combustion noise source from other noise sources measured with far-field microphones. This method is compared with a statistics based coherence threshold estimation method. In addition, the un-aligned coherence procedure at the same time also reveals periodicities, spectral lines, and undamped sinusoids hidden by broadband turbofan engine noise. In calculating the coherence threshold using a statistical method, one may use either the number of independent records or a larger number corresponding to the number of overlapped records used to create the average. Using data from a turbofan engine and a simulation this paper shows that applying the Fisher z-transform to the un-aligned coherence can aid in making the proper selection of samples and produce a reasonable statistics based coherence threshold. Examples are presented showing that the underlying tonal and coherent broad band structure which is buried under random broadband noise and jet noise can be determined. The method also shows the possible presence of indirect combustion noise. Copyright 2011 Acoustical Society of America. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the Acoustical Society of America.

  15. 76 FR 77108 - Airworthiness Directives; International Aero Engines Turbofan Engines

    Science.gov (United States)

    2011-12-12

    ... turbine (HPT) case burn-through events, numerous reports of loss of stage 1 blade outer air seal segments... HPT case burn-through, uncontrolled under-cowl engine fire, and damage to the airplane. DATES: This AD... disagree. The EGT margin requirement in this AD accounts for the operating environment. The calculation of...

  16. 76 FR 292 - Airworthiness Directives; General Electric Company CF6-45 and CF6-50 Series Turbofan Engines

    Science.gov (United States)

    2011-01-04

    ...-24145; Directorate Identifier 2006-NE-06-AD] RIN 2120-AA64 Airworthiness Directives; General Electric Company CF6-45 and CF6-50 Series Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT... airworthiness directive (AD) that applies to General Electric Company (GE) CF6-45 and CF6-50 series turbofan...

  17. 77 FR 71085 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines

    Science.gov (United States)

    2012-11-29

    ... Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines AGENCY: Federal Aviation... directive (AD) for certain serial number (S/N) Rolls-Royce Deutschland Ltd & Co KG (RRD) TAY 620- 15... identified in this AD, contact Rolls-Royce Deutschland Ltd & Co KG, Eschenweg 11, Dahlewitz, 15827...

  18. 77 FR 6668 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2012-02-09

    ... fuel pump to the fuel-oil-heat exchanger, and the clips holding the LP fuel tube run from the LP filter... pump to the fuel-oil-heat exchanger, and the LP fuel tube run from the LP filter to the HP fuel pump... Airworthiness Directives; Rolls-Royce plc Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT...

  19. 77 FR 73268 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2012-12-10

    ... certain Rolls-Royce plc (RR) RB211-Trent 900 series turbofan engines. This AD requires inspection of the.... (c) Applicability This AD applies to Rolls-Royce plc (RR) RB211-Trent 970-84 and 972-84 series... this AD using RR Technical Variance (TV) 125436, issue 2, dated July 27, 2012, you met the requirements...

  20. 77 FR 32007 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2012-05-31

    ...We are adopting a new airworthiness directive (AD) for all Rolls-Royce plc (RR) RB211-Trent 800 series turbofan engines. This AD requires removal from service of certain critical engine parts based on reduced life limits. This AD was prompted by RR adding a new flight profile and an associated set of life limits. We are issuing this AD to prevent the failure of critical rotating parts, which could result in uncontained failure of the engine and damage to the airplane.

  1. 77 FR 10950 - Airworthiness Directives; General Electric Company (GE) Turbofan Engines

    Science.gov (United States)

    2012-02-24

    ...) for all GE CF6-80C2B series turbofan engines. That AD currently requires installing software version 8.2.Q1 to the engine electronic control unit (ECU), which increases the engine's margin to flameout... the list of affected ECU P/Ns in Table 2 of the AD, ECUs with software version 8.2.Q1 and 8.2.R, a new...

  2. 76 FR 65997 - Airworthiness Directives; Rolls-Royce plc (RR) RB211-535 Series Turbofan Engines

    Science.gov (United States)

    2011-10-25

    ...'' is induction of an engine into the shop for any purpose where: (1) All the blades are removed from...) RB211-535 Series Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of... applies to all RR RB211-535E4-37, -535E4-B-37, -535E4-B-75, and -535E4-C-37 turbofan engines. The existing...

  3. Comparative performance analysis of combined-cycle pulse detonation turbofan engines (PDTEs

    Directory of Open Access Journals (Sweden)

    Sudip Bhattrai

    2013-09-01

    Full Text Available Combined-cycle pulse detonation engines are promising contenders for hypersonic propulsion systems. In the present study, design and propulsive performance analysis of combined-cycle pulse detonation turbofan engines (PDTEs is presented. Analysis is done with respect to Mach number at two consecutive modes of operation: (1 Combined-cycle PDTE using a pulse detonation afterburner mode (PDA-mode and (2 combined-cycle PDTE in pulse detonation ramjet engine mode (PDRE-mode. The performance of combined-cycle PDTEs is compared with baseline afterburning turbofan and ramjet engines. The comparison of afterburning modes is done for Mach numbers from 0 to 3 at 15.24 km altitude conditions, while that of pulse detonation ramjet engine (PDRE is done for Mach 1.5 to Mach 6 at 18.3 km altitude conditions. The analysis shows that the propulsive performance of a turbine engine can be greatly improved by replacing the conventional afterburner with a pulse detonation afterburner (PDA. The PDRE also outperforms its ramjet counterpart at all flight conditions considered herein. The gains obtained are outstanding for both the combined-cycle PDTE modes compared to baseline turbofan and ramjet engines.

  4. An Assessment of Gas Foil Bearing Scalability and the Potential Benefits to Civilian Turbofan Engines

    Science.gov (United States)

    Bruckner, Robert J.

    2010-01-01

    Over the past several years the term oil-free turbomachinery has been used to describe a rotor support system for high speed turbomachinery that does not require oil for lubrication, damping, or cooling. The foundation technology for oil-free turbomachinery is the compliant foil bearing. This technology can replace the conventional rolling element bearings found in current engines. Two major benefits are realized with this technology. The primary benefit is the elimination of the oil lubrication system, accessory gearbox, tower shaft, and one turbine frame. These components account for 8 to 13 percent of the turbofan engine weight. The second benefit that compliant foil bearings offer to turbofan engines is the capability to operate at higher rotational speeds and shaft diameters. While traditional rolling element bearings have diminished life, reliability, and load capacity with increasing speeds, the foil bearing has a load capacity proportional to speed. The traditional applications for foil bearings have been in small, lightweight machines. However, recent advancements in the design and manufacturing of foil bearings have increased their potential size. An analysis, grounded in experimentally proven operation, is performed to assess the scalability of the modern foil bearing. This analysis was coupled to the requirements of civilian turbofan engines. The application of the foil bearing to larger, high bypass ratio engines nominally at the 120 kN (approx.25000 lb) thrust class has been examined. The application of this advanced technology to this system was found to reduce mission fuel burn by 3.05 percent.

  5. Investigation of a Verification and Validation Tool with a Turbofan Aircraft Engine Application

    Science.gov (United States)

    Uth, Peter; Narang-Siddarth, Anshu; Wong, Edmond

    2018-01-01

    The development of more advanced control architectures for turbofan aircraft engines can yield gains in performance and efficiency over the lifetime of an engine. However, the implementation of these increasingly complex controllers is contingent on their ability to provide safe, reliable engine operation. Therefore, having the means to verify the safety of new control algorithms is crucial. As a step towards this goal, CoCoSim, a publicly available verification tool for Simulink, is used to analyze C-MAPSS40k, a 40,000 lbf class turbo-fan engine model developed at NASA for testing new control algorithms. Due to current limitations of the verification software, several modifications are made to C-MAPSS40k to achieve compatibility with CoCoSim. Some of these modifications sacrifice fidelity to the original model. Several safety and performance requirements typical for turbofan engines are identified and constructed into a verification framework. Preliminary results using an industry standard baseline controller for these requirements are presented. While verification capabilities are demonstrated, a truly comprehensive analysis will require further development of the verification tool.

  6. 77 FR 20987 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2012-04-09

    ...The FAA is correcting an airworthiness directive (AD) that published in the Federal Register. That AD applies to RB211-Trent 800 series turbofan engines. The last comment response in the preamble and the first sentence of regulatory text paragraph (g)(1) are incorrect. The repetitive inspection interval should be 2,000 flight cycles, not 1,000 flight cycles. This document corrects those errors. In all other respects, the original document remains the same.

  7. 77 FR 9869 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG (RRD) Turbofan Engines

    Science.gov (United States)

    2012-02-21

    ... Deutschland Ltd & Co KG (RRD) Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION..., Amendment 39-15860 (74 FR 12086, March 23, 2009): Rolls-Royce Deutschland Ltd & Co KG (formerly BMW Rolls... applies to Rolls-Royce Deutschland Ltd & Co KG BR700- 715A1-30, BR700-715B1-30, and BR700-715C1-30...

  8. 78 FR 2195 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines

    Science.gov (United States)

    2013-01-10

    ... Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines AGENCY: Federal Aviation Administration (FAA... (AD) for all Rolls-Royce Deutschland Ltd & Co KG BR700-715A1-30, BR700-715B1-30, and BR700-715C1-30... identified in this AD, contact Rolls-Royce Deutschland Ltd & Co KG, Eschenweg 11, Dahlewitz, 15827...

  9. 77 FR 39156 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG (RRD) Turbofan Engines

    Science.gov (United States)

    2012-07-02

    ... Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG (RRD) Turbofan Engines AGENCY: Federal Aviation... 39-15860 (74 FR 12086, March 23, 2009): 2009-07-01 R1 Rolls-Royce Deutschland Ltd & Co KG (formerly... applies to Rolls-Royce Deutschland Ltd & Co KG BR700- 715A1-30, BR700-715B1-30, and BR700-715C1-30...

  10. 76 FR 30529 - Airworthiness Directives; Rolls-Royce plc (RR) RB211-535 Series Turbofan Engines

    Science.gov (United States)

    2011-05-26

    ... proposed AD to ``For the purpose of this AD, an ``engine shop visit'' is the induction of an engine into... service. Definitions (f) For the purpose of this AD, an ``engine shop visit'' is: (1) Induction of an... Airworthiness Directives; Rolls-Royce plc (RR) RB211-535 Series Turbofan Engines AGENCY: Federal Aviation...

  11. 75 FR 61361 - Airworthiness Directives; Rolls-Royce plc (RR) RB211-535 Series Turbofan Engines

    Science.gov (United States)

    2010-10-05

    ... ``engine shop visit'' is the induction of an engine into the shop for maintenance involving the separation...) RB211-535 Series Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of... containment capabilities of the engine casings. Thus, cracking at the firtrees of LP Turbine discs constitutes...

  12. 75 FR 62319 - Airworthiness Directives; Pratt & Whitney JT8D-9, -9A, -11, -15, -17, and -17R Turbofan Engines

    Science.gov (United States)

    2010-10-08

    ... AD, a shop visit is the induction of an engine into the shop for maintenance involving the separation... Directives; Pratt & Whitney JT8D-9, -9A, -11, -15, -17, and -17R Turbofan Engines AGENCY: Federal Aviation...) for Pratt & Whitney (PW) JT8D-9, -9A, -11, -15, -17, and -17R turbofan engines. This AD requires...

  13. 75 FR 27972 - Airworthiness Directives; Pratt & Whitney JT8D-9, -9A, -11, -15, -17, and -17R Turbofan Engines

    Science.gov (United States)

    2010-05-19

    ... purpose of this AD, a shop visit is the induction of an engine into the shop for maintenance involving the... JT8D-9, -9A, -11, -15, -17, and -17R Turbofan Engines AGENCY: Federal Aviation Administration (FAA... airworthiness directive (AD) for Pratt & Whitney (PW) JT8D-9, -9A, -11, -15, -17, and -17R turbofan engines...

  14. 76 FR 72650 - Airworthiness Directives; Rolls-Royce plc (RR) RB211 Trent 800 Series Turbofan Engines

    Science.gov (United States)

    2011-11-25

    ... of this AD, the term shop visit means the induction of an engine into the shop for maintenance where...) RB211 Trent 800 Series Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION... this AD to prevent uncontained engine failure and damage to the airplane. DATES: We must receive...

  15. 75 FR 49368 - Airworthiness Directives; Rolls-Royce plc (RR) RB211-Trent 900 Series Turbofan Engines

    Science.gov (United States)

    2010-08-13

    ... induction of an engine into the shop for maintenance involving the separation of pairs of major mating... Airworthiness Directives; Rolls-Royce plc (RR) RB211-Trent 900 Series Turbofan Engines AGENCY: Federal Aviation... condition on an aviation product. The MCAI describes the unsafe condition as: Wear, beyond Engine Manual...

  16. 77 FR 4648 - Airworthiness Directives; Rolls-Royce plc (RR) RB211-535 Series Turbofan Engine

    Science.gov (United States)

    2012-01-31

    ...'' is induction of an engine into the shop for any purpose where: (1) All the blades are removed from... Airworthiness Directives; Rolls-Royce plc (RR) RB211-535 Series Turbofan Engine AGENCY: Federal Aviation... engines. That AD currently requires performing initial and repetitive visual and fluorescent penetrant...

  17. 77 FR 56760 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2012-09-14

    ...We are adopting a new airworthiness directive (AD) for all Rolls-Royce plc (RR) RB211-Trent 800 series turbofan engines. This AD requires removing from service certain intermediate pressure (IP) turbine discs that have a serial number listed in this AD. This AD was prompted by RR performing an evaluation that determined that the current lives for certain IP turbine discs with a steel inclusion may fail before they reach their current mandatory life limits. We are issuing this AD to prevent failure of the IP turbine disc, which could result in uncontained failure of the engine and damage to the airplane.

  18. 78 FR 70487 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2013-11-26

    ...We are adopting a new airworthiness directive (AD) for Rolls- Royce plc (RR) RB211-535E4-37, -535E4-B-37, -535E4-C-37, RB211Trent 768-60, 772-60, and 772B-60 turbofan engines. This AD requires removal of certain high-pressure (HP) and intermediate-pressure (IP) turbine discs before their accumulated cyclic lives have reached the revised limits. This AD was prompted by a report of an HP disc contaminated with a steel inclusion. We are issuing this AD to prevent failure of the HP or IP turbine disc, uncontained engine failure, and damage to the airplane.

  19. 76 FR 255 - Airworthiness Directives; Pratt & Whitney Canada Corp. (P&WC) PW305A and PW305B Turbofan Engines

    Science.gov (United States)

    2011-01-04

    ... Canada Corp. (P&WC) PW305A and PW305B Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT... between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this AD... section of the engine maintenance manuals for Pratt & Whitney Canada (P&WC) PW305A and PW305B turbofan...

  20. 76 FR 30573 - Airworthiness Directives; General Electric Company (GE) GE90-110B1 and GE90-115B Turbofan Engines

    Science.gov (United States)

    2011-05-26

    ... applies to General Electric Company (GE) GE90-110B1 and GE90-115B turbofan engines with high-pressure...-0278; Directorate Identifier 2010-NE-10-AD] RIN 2120-AA64 Airworthiness Directives; General Electric Company (GE) GE90- 110B1 and GE90-115B Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT...

  1. Eulerian method for ice crystal icing in turbofan engines

    NARCIS (Netherlands)

    Norde, Ellen

    2017-01-01

    The newer generations of high-bypass-ratio engines are susceptible to the ingestion of small ice crystals which may cause engine power loss or damage. The research presented in this thesis focusses on the development of a computational method for in-engine ice crystal accretion. The work has been

  2. Recent status on development of the turbofan engine in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Matsuki, M.; Torisaki, T.; Miyazawa, K.

    1974-01-01

    Efforts to design and develop new jet engines have been made in Japan since 1953. One family of propulsion engine (J3) succeeded in getting into production to be installed on two models of Japanese developed aircraft (T1B and P2J). Another family of lift engine (JR) has been successfully used for overall VTOL system studies. Based on these experiences, studies on a new fan engine for main propulsion are being carried out. This new engine (FJR-710) is a high bypass front engine developed for low noise generation and low smoke emission. The interim goal for the engine is an exhaust smoke density below AIA 25. A combustor of the air-swirl atomizer type has been adopted which can successfully reduce smoke.

  3. 78 FR 44899 - Airworthiness Directives; General Electric Company Turbofan Engines

    Science.gov (United States)

    2013-07-25

    ... AD to prevent failure of the affected fuel supply tube, fuel leakage, engine fire, and damage to the... fire. The vibratory excitation frequency of this VBV actuator fuel supply tube mode shape is within the frequency range generated by the engine during cruise. Because the tube's end weld is a high stress...

  4. A Comparison of Hybrid Approaches for Turbofan Engine Gas Path Fault Diagnosis

    Science.gov (United States)

    Lu, Feng; Wang, Yafan; Huang, Jinquan; Wang, Qihang

    2016-09-01

    A hybrid diagnostic method utilizing Extended Kalman Filter (EKF) and Adaptive Genetic Algorithm (AGA) is presented for performance degradation estimation and sensor anomaly detection of turbofan engine. The EKF is used to estimate engine component performance degradation for gas path fault diagnosis. The AGA is introduced in the integrated architecture and applied for sensor bias detection. The contributions of this work are the comparisons of Kalman Filters (KF)-AGA algorithms and Neural Networks (NN)-AGA algorithms with a unified framework for gas path fault diagnosis. The NN needs to be trained off-line with a large number of prior fault mode data. When new fault mode occurs, estimation accuracy by the NN evidently decreases. However, the application of the Linearized Kalman Filter (LKF) and EKF will not be restricted in such case. The crossover factor and the mutation factor are adapted to the fitness function at each generation in the AGA, and it consumes less time to search for the optimal sensor bias value compared to the Genetic Algorithm (GA). In a word, we conclude that the hybrid EKF-AGA algorithm is the best choice for gas path fault diagnosis of turbofan engine among the algorithms discussed.

  5. Multiplexed Predictive Control of a Large Commercial Turbofan Engine

    Science.gov (United States)

    Richter, hanz; Singaraju, Anil; Litt, Jonathan S.

    2008-01-01

    Model predictive control is a strategy well-suited to handle the highly complex, nonlinear, uncertain, and constrained dynamics involved in aircraft engine control problems. However, it has thus far been infeasible to implement model predictive control in engine control applications, because of the combination of model complexity and the time allotted for the control update calculation. In this paper, a multiplexed implementation is proposed that dramatically reduces the computational burden of the quadratic programming optimization that must be solved online as part of the model-predictive-control algorithm. Actuator updates are calculated sequentially and cyclically in a multiplexed implementation, as opposed to the simultaneous optimization taking place in conventional model predictive control. Theoretical aspects are discussed based on a nominal model, and actual computational savings are demonstrated using a realistic commercial engine model.

  6. 77 FR 76977 - Airworthiness Directives; General Electric Company Turbofan Engines

    Science.gov (United States)

    2012-12-31

    ... reference to P/N MS9557-12 from the compliance and prohibition paragraphs. Request To Remove Idle Leak Check... supporting bracket to eliminate mis-assembly. This supplemental action adds an engine model, alters the list... compliance. We are reopening the comment period to allow the public the opportunity to comment on these...

  7. 78 FR 24671 - Airworthiness Directives; General Electric Company Turbofan Engines

    Science.gov (United States)

    2013-04-26

    ... AD to prevent high-pressure fuel leaks caused by improper seating of fuel tube flanges, which could... identify the spray shield P/Ns in the AD. Request To Add Engine Shop Visit Definition Atlas Air requested... (IDG) fuel-oil cooler. We are issuing this AD to prevent high-pressure fuel leaks caused by improper...

  8. Load Sharing Behavior of Star Gearing Reducer for Geared Turbofan Engine

    Science.gov (United States)

    Mo, Shuai; Zhang, Yidu; Wu, Qiong; Wang, Feiming; Matsumura, Shigeki; Houjoh, Haruo

    2017-07-01

    Load sharing behavior is very important for power-split gearing system, star gearing reducer as a new type and special transmission system can be used in many industry fields. However, there is few literature regarding the key multiple-split load sharing issue in main gearbox used in new type geared turbofan engine. Further mechanism analysis are made on load sharing behavior among star gears of star gearing reducer for geared turbofan engine. Comprehensive meshing error analysis are conducted on eccentricity error, gear thickness error, base pitch error, assembly error, and bearing error of star gearing reducer respectively. Floating meshing error resulting from meshing clearance variation caused by the simultaneous floating of sun gear and annular gear are taken into account. A refined mathematical model for load sharing coefficient calculation is established in consideration of different meshing stiffness and supporting stiffness for components. The regular curves of load sharing coefficient under the influence of interactions, single action and single variation of various component errors are obtained. The accurate sensitivity of load sharing coefficient toward different errors is mastered. The load sharing coefficient of star gearing reducer is 1.033 and the maximum meshing force in gear tooth is about 3010 N. This paper provides scientific theory evidences for optimal parameter design and proper tolerance distribution in advanced development and manufacturing process, so as to achieve optimal effects in economy and technology.

  9. 77 FR 20508 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2012-04-05

    ...We are superseding an existing airworthiness directive (AD) for all Rolls-Royce plc (RR) RB211-Trent 875-17, RB211-Trent 877-17, RB211-Trent 884-17, RB211-Trent 884B-17, RB211-Trent 892-17, RB211- Trent 892B-17, and RB211-Trent 895-17 turbofan engines. That AD currently requires initial and repetitive ultrasonic inspections (UIs) of certain low-pressure (LP) compressor blades identified by serial number (S/N). This AD requires the same actions but expands the population of blades. This AD was prompted by RR concluding that additional blades affected must be inspected. We are issuing this AD to prevent LP compressor blades from failing due to blade root cracks, which could lead to uncontained engine failure and damage to the airplane.

  10. 77 FR 26216 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2012-05-03

    ...We propose to supersede an existing airworthiness directive (AD) that applies to all Rolls-Royce plc (RR) RB211-Trent 875-17, RB211-Trent 877-17, RB211-Trent 884-17, RB211-Trent 884B-17, RB211- Trent 892-17, RB211-Trent 892B-17, and RB211-Trent 895-17 turbofan engines. The existing AD currently requires initial and repetitive ultrasonic inspections (UIs) of certain low-pressure (LP) compressor blades identified by serial number (S/N). This proposed AD would require the same actions but expands the population of blades. We are proposing this AD to prevent LP compressor blades from failing due to blade root cracks, which could lead to uncontained engine failure and damage to the airplane.

  11. Measurement of far field combustion noise from a turbofan engine using coherence functions

    Science.gov (United States)

    Karchmer, A. M.; Reshotko, M.; Montegani, F. J.

    1977-01-01

    Coherence measurements between fluctuating pressure in the combustor of a YF-102 turbofan engine and far-field acoustic pressure were made. The results indicated that a coherent relationship between the combustor pressure and far-field existed only at frequencies below 250 Hz, with the peak occurring near 125 Hz. The coherence functions and the far-field spectra were used to compute the combustor-associated far-field noise in terms of spectra, directivity, and acoustic power, over a range of engine operating conditions. The acoustic results so measured were compared with results obtained by conventional methods, as well as with various semiempirical predictions schemes. Examination of the directivity patterns indicated a peak in the combustion noise near 120 deg (relative to the inlet axis).

  12. Theoretical aspects of an electrostatic aerosol filter for civilian turbofan engines

    Directory of Open Access Journals (Sweden)

    Valeriu DRAGAN

    2012-03-01

    Full Text Available The paper addresses the problem of aerosol filtration in turbofan engines. The current problem of very fine aerosol admission is the impossibility for mechanical filtration; another aspect of the problem is the high mass flow of air to be filtered. Non-attended, the aerosol admission can -and usually does- lead to clogging of turbine cooling passages and can damage the engine completely. The approach is theoretical and relies on the principles of electrostatic dust collectors known in other industries. An estimative equation is deduced in order to quantify the electrical charge required to obtain the desired filtration. Although the device still needs more theoretical and experimental work, it could one day be used as a means of increasing the safety of airplanes passing trough an aerosol laden mass of air.

  13. Model-based Acceleration Control of Turbofan Engines with a Hammerstein-Wiener Representation

    Science.gov (United States)

    Wang, Jiqiang; Ye, Zhifeng; Hu, Zhongzhi; Wu, Xin; Dimirovsky, Georgi; Yue, Hong

    2017-05-01

    Acceleration control of turbofan engines is conventionally designed through either schedule-based or acceleration-based approach. With the widespread acceptance of model-based design in aviation industry, it becomes necessary to investigate the issues associated with model-based design for acceleration control. In this paper, the challenges for implementing model-based acceleration control are explained; a novel Hammerstein-Wiener representation of engine models is introduced; based on the Hammerstein-Wiener model, a nonlinear generalized minimum variance type of optimal control law is derived; the feature of the proposed approach is that it does not require the inversion operation that usually upsets those nonlinear control techniques. The effectiveness of the proposed control design method is validated through a detailed numerical study.

  14. Dynamic Analysis for a Geared Turbofan Engine with Variable Area Fan Nozzle

    Science.gov (United States)

    Csank, Jeffrey T.; Thomas, George L.

    2017-01-01

    Aggressive design goals have been set for future aero-propulsion systems with regards to fuel economy, noise, and emissions. To meet these challenging goals, advanced propulsion concepts are being explored and current operating margins are being re-evaluated to find additional concessions that can be made. One advanced propulsion concept being evaluated is a geared turbofan with a variable area fan nozzle (VAFN), developed by NASA. This engine features a small core, a fan driven by the low pressure turbine through a reduction gearbox, and a shape memory alloy (SMA)-actuated VAFN. The VAFN is designed to allow both a small exit area for efficient operation at cruise, while being able to open wider at high power conditions to reduce backpressure on the fan and ensure a safe level of stall margin is maintained. The VAFN is actuated via a SMA-based system instead of a conventional system to decrease overall weight of the system, however, SMA-based actuators respond relatively slowly, which introduces dynamic issues that are investigated in this work. This paper describes both a control system designed specifically for issues associated with SMAs, and dynamic analysis of the geared turbofan VAFN with the SMA actuators. Also, some future recommendations are provided for this type of propulsion system.

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

    Science.gov (United States)

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

    2017-11-01

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

  16. 78 FR 17300 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2013-03-21

    ...We propose to supersede an existing airworthiness directive (AD) for all Rolls-Royce plc (RR) RB211-Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B-61, 556B2-61, 560-61, 560A2-61, 768-60, 772-60, 772B-60, 875-17, 877-17, 884-17, 884B-17, 892-17, 892B-17, and 895-17 turbofan engines. The existing AD currently requires inspection of the intermediate-pressure (IP) compressor rotor shaft rear balance land for cracks. Since we issued that AD, a crack was detected in a Trent 500 IP compressor rotor shaft rear balance land during a shop visit, and further engineering evaluation done by RR concluded that the cracking may also exist in Trent 900 engines. This proposed AD would require inspections of the IP compressor rotor shaft as required by the existing AD while adding on-wing inspections for the Trent 500 engines, and on-wing and in-shop inspections for the Trent 900 engines. We are proposing this AD to detect cracking on the IP compressor rotor shaft rear balance land, which could lead to uncontained engine failure and damage to the airplane.

  17. 78 FR 54149 - Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines

    Science.gov (United States)

    2013-09-03

    ...We are superseding airworthiness directive (AD) 2012-10-12 for all RR RB211-Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B-61, 556B2- 61, 560-61, 560A2-61, 768-60, 772-60, 772B-60, 875-17, 877-17, 884-17, 884B-17, 892-17, 892B-17, and 895-17 turbofan engines. AD 2012-10-12 required inspecting the intermediate-pressure (IP) compressor rotor shaft rear balance land for cracks. We are issuing this AD to require inspections of the IP compressor rotor shaft, as required by AD 2012- 10-12, to add on-wing inspections for the Trent 500 engines, and to add on-wing and in-shop inspections for the Trent 900 engines. This AD was prompted by detection of a crack in a Trent 500 IP compressor rotor shaft rear balance land during a shop visit. Further engineering evaluation, done by RR, concluded that the cracking may also exist in Trent 900 engines. We are issuing this AD to detect cracking on the IP compressor rotor shaft rear balance land, which could lead to uncontained engine failure and damage to the airplane.

  18. 78 FR 28161 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2013-05-14

    ...We propose to supersede an existing airworthiness directive (AD) that applies to all Rolls-Royce plc (RR) model RB211 Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B-61, 556B2-61, 560-61, and 560A2-61; and RB211 Trent 768-60, 772-60, and 772B-60; and RB211-Trent 875-17, 877-17, 884-17, 884B-17, 892-17, 892B-17, and 895-17; and RB211-524G2- T-19, -524G3-T-19, -524H-T-36, and -524H2-T-19 turbofan engines that have a high-pressure (HP) compressor stage 1 to 4 rotor disc installed, with a certain part number (P/N) installed. The existing AD requires repetitive inspections of the axial dovetail slots, and follow-on corrective action depending on findings. This proposed AD expands the population of affected parts. This proposed AD also changes, for the purposes of this AD, the definition of ``engine shop visit.'' We are proposing this AD to detect cracks in the HP compressor stage 1 and 2 disc posts, which could result in failure of the disc post and HP compressor blades, damage to the engine, and damage to the airplane.

  19. 78 FR 60658 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2013-10-02

    ...We are superseding airworthiness directive (AD) AD 2012-04-13, for all Rolls-Royce plc (RR) model RB211 Trent 553-61, 553A2-61, 556- 61, 556A2-61, 556B-61, 556B2-61, 560-61, and 560A2-61; and RB211 Trent 768-60, 772-60, and 772B-60; and RB211-Trent 875-17, 877-17, 884-17, 884B-17, 892-17, 892B-17, and 895-17; and RB211-524G2-T-19, -524G3-T- 19, -524H-T-36, and -524H2-T-19 turbofan engines that have a high- pressure (HP) compressor stage 1 to 4 rotor disc installed, with a certain part number (P/N) installed. AD 2012-04-13 required repetitive inspections of the axial dovetail slots and follow-on corrective action depending on findings. This new AD expands the population of affected parts. This AD also changes, for the purposes of this AD, the definition of ``engine shop visit.'' This AD was prompted by reports of additional affected HP compressor rotor discs that require the same action. We are issuing this AD to detect cracks in the HP compressor stage 1 and 2 disc posts, which could result in failure of the disc post and HP compressor blades, damage to the engine, and damage to the airplane.

  20. 77 FR 2932 - Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines

    Science.gov (United States)

    2012-01-20

    ...We are revising an earlier proposed airworthiness directive (AD) for all RR RB211-Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B- 61, 556B2-61, 560-61, 560A2-61, 768-60, 772-60, 772B-60, 875-17, 877- 17, 884-17, 884B-17, 892-17, 892B-17, and 895-17 turbofan engines. That NPRM proposed to supersede an existing AD that requires inspecting the intermediate-pressure (IP) compressor rotor shaft rear balance land for cracks, which could lead to engine failure. This action revises that NPRM by changing the optional terminating action for RB211-Trent 700 and RB211-Trent 800 engines to mandatory terminating action. Since these actions impose an additional burden over that proposed in the NPRM, we are reopening the comment period to allow the public the chance to comment on these proposed changes.

  1. 75 FR 51654 - Airworthiness Directives; Rolls-Royce plc (RR) RB211-22B and RB211-524 Series Turbofan Engines

    Science.gov (United States)

    2010-08-23

    ... engine shop visit is the induction of an engine into the shop for maintenance involving the separation of... Airworthiness Directives; Rolls-Royce plc (RR) RB211-22B and RB211-524 Series Turbofan Engines AGENCY: Federal... in the associated engine manual. The cracks have been found to initiate from corrosion pits...

  2. 76 FR 65136 - Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines

    Science.gov (United States)

    2011-10-20

    ...We propose to supersede an existing airworthiness directive (AD) that applies to all RR model RB211-524G2-T-19, -524G3-T-19, -524H- T-36, and -524H2-T-19; and RB211-Trent 553-61, 553A2-61, 556-61, 556A2- 61, 556B-61, 556B2-61, 560-61, 560A2-61; RB211-Trent 768-60, 772-60, 772B-60; and RB211-Trent 875-17, 877-17, 884-17, 884B-17, 892-17, 892B- 17, and 895-17 turbofan engines that have a high-pressure (HP) compressor stage 1 to 4 rotor disc with a part number (P/N) listed in Table 1 of this proposed AD. The existing AD currently requires repetitive inspections of the axial dovetail slots, and follow-on corrective action depending on findings. Since we issued that AD, we determined that the definition of shop visit is too restrictive in the existing AD. This proposed AD would continue to require those repetitive inspections and follow-on corrective actions, and it would change the definition of a shop visit to be less restrictive. We are proposing this AD to detect cracks in the HP compressor stage 1 and 2 disc posts, which could result in failure of the disc post and HP compressor blades, release of uncontained engine debris, and damage to the airplane.

  3. 76 FR 64283 - Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines

    Science.gov (United States)

    2011-10-18

    ...We propose to supersede an existing airworthiness directive (AD) that applies to all RR RB211-Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B-61, 556B2-61, 560-61, 560A2-61, 768-60, 772-60, 772B-60, 875-17, 877-17, 884-17, 884B-17, 892-17, 892B-17, and 895-17 turbofan engines. The existing AD currently requires inspecting the intermediate-pressure (IP) compressor rotor shaft rear balance land for cracks. Since we issued that AD, we received reports of one RB211-Trent 700 and two additional RB211-Trent 800 IP compressor rotor shafts that have been found cracked. This proposed AD would continue to require initial inspections, add additional inspections, and an optional terminating action. The cracking identified above could lead to IP compressor rotor shaft failure, uncontained engine failure, and damage to the airplane. We are proposing this AD to correct the unsafe condition on these products.

  4. 77 FR 58762 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2012-09-24

    ...We are superseding an existing airworthiness directive (AD) for all Rolls-Royce plc (RR) RB211-Trent 875-17, RB211-Trent 877-17, RB211-Trent 884-17, RB211-Trent 884B-17, RB211-Trent 892-17, RB211- Trent 892B-17, and RB211-Trent 895-17 turbofan engines. That AD currently requires initial and repetitive ultrasonic inspections (UIs) of certain low-pressure (LP) compressor blades identified by serial number (S/N). This new AD requires the same actions but expands the population of blades. This AD was prompted by the need to add the inspections of the LP compressor blades listed by S/N in Appendices 3H through 3L of RR plc Alert Service Bulletin (ASB) No. RB.211-72-AG244, Revision 4, dated December 22, 2011. We are issuing this AD to prevent multiple LP compressor blades from failing due to blade root cracks, which could lead to uncontained engine failure and damage to the airplane.

  5. Time Delay Analysis of Turbofan Engine Direct and Indirect Combustion Noise Sources

    Science.gov (United States)

    Miles, Jeffrey Hilton

    2008-01-01

    The core noise components of a dual spool turbofan engine were separated by the use of a coherence function. A source location technique based on adjusting the time delay between the combustor pressure sensor signal and the far-field microphone signal to maximize the coherence and remove as much variation of the phase angle with frequency as possible was used. The discovery was made that for the 130o microphone a 90.027 ms time shift worked best for the frequency band from 0 to 200 Hz while a 86.975 ms time shift worked best for the frequency band from 200 to 400 Hz. Hence, the 0 to 200 Hz band signal took more time than the 200 to 400 Hz band signal to travel the same distance. This suggests the 0 to 200 Hz coherent cross spectral density band is partly due to indirect combustion noise attributed to entropy fluctuations, which travel at the flow velocity, interacting with the turbine. The signal in the 200 to 400 Hz frequency band is attributed mostly to direct combustion noise. Results are presented herein for engine power settings of 48, 54, and 60 percent of the maximum power setting

  6. 75 FR 27964 - Airworthiness Directives; Rolls-Royce plc (RR) RB211-22B and RB211-524 Series Turbofan Engines

    Science.gov (United States)

    2010-05-19

    ... before further flight. Definitions (4) For the purpose of this AD, an engine shop visit is the induction...) RB211-22B and RB211-524 Series Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT...) technique defined in the associated engine manual. The cracks have been found to initiate from corrosion...

  7. 77 FR 31176 - Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines

    Science.gov (United States)

    2012-05-25

    ...We are superseding an existing airworthiness directive (AD) for all RR RB211-Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B-61, 556B2-61, 560-61, 560A2-61, 768-60, 772-60, 772B-60, 875-17, 877-17, 884-17, 884B-17, 892-17, 892B-17, and 895-17 turbofan engines. That AD currently requires inspecting the intermediate-pressure (IP) compressor rotor shaft rear balance land for cracks. This new AD continues to require initial inspections, adds additional inspections, and a mandatory terminating action. This AD was prompted by additional cracking on RB211-Trent 700 and RB211-Trent 800 IP compressor rotor shafts found since the existing AD was issued. We are issuing this AD to detect cracking on the IP compressor rotor rear balance land. IP compressor rotor rear balance land cracking can lead to uncontained failure of the rotor and damage to the airplane.

  8. Core Noise Diagnostics of Turbofan Engine Noise Using Correlation and Coherence Functions

    Science.gov (United States)

    Miles, Jeffrey H.

    2009-01-01

    Cross-correlation and coherence functions are used to look for periodic acoustic components in turbofan engine combustor time histories, to investigate direct and indirect combustion noise source separation based on signal propagation time delays, and to provide information on combustor acoustics. Using the cross-correlation function, time delays were identified in all cases, clearly indicating the combustor is the source of the noise. In addition, unfiltered and low-pass filtered at 400 Hz signals had a cross-correlation time delay near 90 ms, while the low-pass filtered at less than 400 Hz signals had a cross-correlation time delay longer than 90 ms. Low-pass filtering at frequencies less than 400 Hz partially removes the direct combustion noise signals. The remainder includes the indirect combustion noise signal, which travels more slowly because of the dependence on the entropy convection velocity in the combustor. Source separation of direct and indirect combustion noise is demonstrated by proper use of low-pass filters with the cross-correlation function for a range of operating conditions. The results may lead to a better idea about the acoustics in the combustor and may help develop and validate improved reduced-order physics-based methods for predicting direct and indirect combustion noise.

  9. Spatial correlation in the ambient core noise field of a turbofan engine.

    Science.gov (United States)

    Miles, Jeffrey Hilton

    2012-06-01

    An acoustic transfer function relating combustion noise and turbine exit noise in the presence of enclosed ambient core noise is investigated using a dynamic system model and an acoustic system model for the particular turbofan engine studied and for a range of operating conditions. Measurements of cross-spectra magnitude and phase between the combustor and turbine exit and auto-spectra at the turbine exit and combustor are used to show the presence of indirect and direct combustion noise over the frequency range of 0-400 Hz. The procedure used evaluates the ratio of direct to indirect combustion noise. The procedure used also evaluates the post-combustion residence time in the combustor which is a factor in the formation of thermal NO(x) and soot in this region. These measurements are masked by the ambient core noise sound field in this frequency range which is observable since the transducers are situated within an acoustic wavelength of one another. An ambient core noise field model based on one and two dimensional spatial correlation functions is used to replicate the spatially correlated response of the pair of transducers. The spatial correlation function increases measured attenuation due to destructive interference and masks the true attenuation of the turbine.

  10. 77 FR 13483 - Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines

    Science.gov (United States)

    2012-03-07

    ...We are superseding an existing airworthiness directive (AD) for all RR model RB211-524G2-T-19, -524G3-T-19, -524H-T-36, and -524H2- T-19; and RB211-Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B-61 556B2-61, 560-61, 560A2-61; RB211-Trent 768-60, 772-60, 772B-60; and RB211-Trent 875-17, 877-17, 884-17, 884B-17, 892-17, 892B-17, and 895- 17 turbofan engines that have a high-pressure (HP) compressor stage 1 to 4 rotor disc with a part number (P/N) listed in Table 1 of the AD. That AD currently requires repetitive inspections of the axial dovetail slots, and follow-on corrective action depending on findings. Since we issued that AD, we determined that the definition of shop visit is too restrictive in the existing AD. This continues to require those repetitive inspections and follow-on corrective actions. This new AD changes the definition of a shop visit to be less restrictive. This AD was prompted by our determination that the definition of ``shop visit'' in the existing AD is too restrictive, in that it would require operators to inspect more often than required to ensure safety. We are issuing this AD to detect cracks in the HP compressor stage 1 and 2 disc posts, which could result in failure of the disc post and HP compressor blades, release of uncontained engine debris, and damage to the airplane.

  11. 76 FR 82103 - Airworthiness Directives; General Electric Company (GE) GE90-110B1 and GE90-115B Turbofan Engines

    Science.gov (United States)

    2011-12-30

    ... Airworthiness Directives; General Electric Company (GE) GE90- 110B1 and GE90-115B Turbofan Engines AGENCY... engine failure, and damage to the airplane. DATES: This AD is effective February 3, 2012. The Director of... General Electric, GE-Aviation, Room 285, 1 Neumann Way, Cincinnati, Ohio 45215; email: [email protected

  12. Broadband Fan Noise Prediction System for Turbofan Engines. Volume 3; Validation and Test Cases

    Science.gov (United States)

    Morin, Bruce L.

    2010-01-01

    Pratt & Whitney has developed a Broadband Fan Noise Prediction System (BFaNS) for turbofan engines. This system computes the noise generated by turbulence impinging on the leading edges of the fan and fan exit guide vane, and noise generated by boundary-layer turbulence passing over the fan trailing edge. BFaNS has been validated on three fan rigs that were tested during the NASA Advanced Subsonic Technology Program (AST). The predicted noise spectra agreed well with measured data. The predicted effects of fan speed, vane count, and vane sweep also agreed well with measurements. The noise prediction system consists of two computer programs: Setup_BFaNS and BFaNS. Setup_BFaNS converts user-specified geometry and flow-field information into a BFaNS input file. From this input file, BFaNS computes the inlet and aft broadband sound power spectra generated by the fan and FEGV. The output file from BFaNS contains the inlet, aft and total sound power spectra from each noise source. This report is the third volume of a three-volume set documenting the Broadband Fan Noise Prediction System: Volume 1: Setup_BFaNS User s Manual and Developer s Guide; Volume 2: BFaNS User s Manual and Developer s Guide; and Volume 3: Validation and Test Cases. The present volume begins with an overview of the Broadband Fan Noise Prediction System, followed by validation studies that were done on three fan rigs. It concludes with recommended improvements and additional studies for BFaNS.

  13. Acoustic Database for Turbofan Engine Core-Noise Sources. I; Volume

    Science.gov (United States)

    Gordon, Grant

    2015-01-01

    In this program, a database of dynamic temperature and dynamic pressure measurements were acquired inside the core of a TECH977 turbofan engine to support investigations of indirect combustion noise. Dynamic temperature and pressure measurements were recorded for engine gas dynamics up to temperatures of 3100 degrees Fahrenheit and transient responses as high as 1000 hertz. These measurements were made at the entrance of the high pressure turbine (HPT) and at the entrance and exit of the low pressure turbine (LPT). Measurements were made at two circumferential clocking positions. In the combustor and inter-turbine duct (ITD), measurements were made at two axial locations to enable the exploration of time delays. The dynamic temperature measurements were made using dual thin-wire thermocouple probes. The dynamic pressure measurements were made using semi-infinite probes. Prior to the engine test, a series of bench, oven, and combustor rig tests were conducted to characterize the performance of the dual wire temperature probes and to define and characterize the data acquisition systems. A measurement solution for acquiring dynamic temperature and pressure data on the engine was defined. A suite of hardware modifications were designed to incorporate the dynamic temperature and pressure instrumentation into the TECH977 engine. In particular, a probe actuation system was developed to protect the delicate temperature probes during engine startup and transients in order to maximize sensor life. A set of temperature probes was procured and the TECH977 engine was assembled with the suite of new and modified hardware. The engine was tested at four steady state operating speeds, with repeats. Dynamic pressure and temperature data were acquired at each condition for at least one minute. At the two highest power settings, temperature data could not be obtained at the forward probe locations since the mean temperatures exceeded the capability of the probes. The temperature data

  14. 75 FR 52435 - Airworthiness Directives; Pratt & Whitney Canada (P&WC) PW530A, PW545A, and PW545B Turbofan Engines

    Science.gov (United States)

    2010-08-26

    ... Canada (P&WC) PW530A, PW545A, and PW545B Turbofan Engines AGENCY: Federal Aviation Administration (FAA.... and 5 p.m., Monday through Friday, except Federal holidays. Fax: (202) 493-2251. Examining the AD... Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The...

  15. CARDIAD approach to system dominance with application to turbofan engine models. [Complex Acceptability Region for DIAgonal Dominance in multivariable systems analysis and design

    Science.gov (United States)

    Schafer, R. M.; Sain, M. K.

    1980-01-01

    The paper presents the CARDIAD (complex acceptability region for diagonal dominance) method for achieving the diagonal dominance condition in the inverse Nyquist array approach to the analysis and design of multivariable systems in the frequency domain. A design example is given for a sixth order, 4-input, 4-output model of a turbofan engine.

  16. Analysis of Uncertainties in Infrared Camera Measurements of a Turbofan Engine in an Altitude Test Cell

    National Research Council Canada - National Science Library

    Morris, Thomas

    2004-01-01

    ... from the facility structure, hot exhaust gases, and the measurement equipment itself. The atmosphere and a protective ZnSe window that shields the camera from the hot engine exhaust also introduce measurement uncertainty due to attenuation...

  17. Parametric (On-Design) Cycle Analysis for a Separate-Exhaust Turbofan Engine With Interstage Turbine Burner

    Science.gov (United States)

    Liew, K. H.; Urip, E.; Yang, S. L.; Siow, Y. K.; Marek, C. J.

    2005-01-01

    Today s modern aircraft is based on air-breathing jet propulsion systems, which use moving fluids as substances to transform energy carried by the fluids into power. Throughout aero-vehicle evolution, improvements have been made to the engine efficiency and pollutants reduction. The major advantages associated with the addition of ITB are an increase in thermal efficiency and reduction in NOx emission. Lower temperature peak in the main combustor results in lower thermal NOx emission and lower amount of cooling air required. This study focuses on a parametric (on-design) cycle analysis of a dual-spool, separate-flow turbofan engine with an Interstage Turbine Burner (ITB). The ITB considered in this paper is a relatively new concept in modern jet engine propulsion. The ITB serves as a secondary combustor and is located between the high- and the low-pressure turbine, i.e., the transition duct. The objective of this study is to use design parameters, such as flight Mach number, compressor pressure ratio, fan pressure ratio, fan bypass ratio, and high-pressure turbine inlet temperature to obtain engine performance parameters, such as specific thrust and thrust specific fuel consumption. Results of this study can provide guidance in identifying the performance characteristics of various engine components, which can then be used to develop, analyze, integrate, and optimize the system performance of turbofan engines with an ITB. Visual Basic program, Microsoft Excel macrocode, and Microsoft Excel neuron code are used to facilitate Microsoft Excel software to plot engine performance versus engine design parameters. This program computes and plots the data sequentially without forcing users to open other types of plotting programs. A user s manual on how to use the program is also included in this report. Furthermore, this stand-alone program is written in conjunction with an off-design program which is an extension of this study. The computed result of a selected design

  18. Identification and measurement of combustion noise from a turbofan engine using correlation and coherence techniques. Ph.D. Thesis

    Science.gov (United States)

    Karchmer, A. M.

    1977-01-01

    Fluctuating pressure measurements within the combustor and tailpipe of a turbofan engine are made simultaneously with far field acoustic measurements. The pressure measurements within the engine are accomplished with cooled semi-infinite waveguide probes utilizing conventional condenser microphones as the transducers. The measurements are taken over a broad range of engine operating conditions and for 16 far field microphone positions between 10 deg and 160 deg relative to the engine inlet axis. Correlation and coherence techniques are used to determine the relative phase and amplitude relationships between the internal pressures and far field acoustic pressures. The results indicate that the combustor is a low frequency source region for acoustic propagation through the tailpipe and out to the far field. Specifically, it is found that the relation between source pressure and the resulting sound pressure involves a 180 deg phase shift. The latter result is obtained by Fourier transforming the cross correlation function between the source pressure and acoustic pressure after removing the propagation delay time. Further, it is found that the transfer function between the source pressure and acoustic pressure has a magnitude approximately proportional to frequency squared. These results are shown to be consistent with a model using a modified source term in Lighthill's turbulence stress tensor, wherein the fluctuating Reynolds stresses are replaced with the pressure fluctuations due to fluctuating entropy.

  19. Numerical modeling of turbulent evaporating gas-droplet two-phase flows in an afterburner diffusor of turbo-fan jet engines

    Science.gov (United States)

    Zhou, Lixing; Zhang, Jian

    1990-11-01

    Two-dimensional turbulent evaporating gas-droplet two-phase flows in an afterburner diffusor of turbofan jet engines are simulated here by a k-epsilon turbulence model and a particle trajectory model. Comparison of predicted gas velocity and temperature distributions with experimental results for the cases without liquid spray shows good agreement. Gas-droplet two-phase flow predictions give plausible droplet trajectories, fuel-vapor concentration distribution, gas-phase velocity and temperature field in the presence of liquid droplets. One run of computation with this method is made for a particular afterburner. The results indicate that the location of the atomizers is not favorable to flame stabilization and combustion efficiency. The proposed numerical modeling can also be adopted for optimization design and performance evaluation of afterburner combustors of turbofan jet engines.

  20. Design and analysis of annular combustion chamber of a low bypass turbofan engine in a jet trainer aircraft

    Directory of Open Access Journals (Sweden)

    C. Priyant Mark

    2016-06-01

    Full Text Available The design of an annular combustion chamber in a gas turbine engine is the backbone of this paper. It is specifically designed for a low bypass turbofan engine in a jet trainer aircraft. The combustion chamber is positioned in between the compressor and turbine. It has to be designed based on the constant pressure, enthalpy addition process. The present methodology deals with the computation of the initial design parameters from benchmarking of real-time industry standards and arriving at optimized values. It is then studied for feasibility and finalized. Then the various dimensions of the combustor are calculated based on different empirical formulas. The air mass flow is then distributed across the zones of the combustor. The cooling requirement is met using the cooling holes. Finally the variations of parameters at different points are calculated. The whole combustion chamber is modeled using Siemens NX 8.0, a modeling software and presented. The model is then analyzed using various parameters at various stages and levels to determine the optimized design. The aerodynamic flow characteristics is simulated numerically by means of ANSYS 14.5 software suite. The air-fuel mixture, combustion-turbulence, thermal and cooling analysis is carried out. The analysis is performed at various scenarios and compared. The results are then presented in image outputs and graphs.

  1. A New Robust Tracking Control Design for Turbofan Engines: H∞/Leitmann Approach

    Directory of Open Access Journals (Sweden)

    Muxuan Pan

    2017-04-01

    Full Text Available In this paper, a H ∞ /Leitmann approach to the robust tracking control design is presented for an uncertain dynamic system. This new method is developed in the following two steps. Firstly, a tracking dynamic system with simultaneous consideration of parameter uncertainty and noise is modeled based on a linear system and a reference model. Accordingly, a “nominal system” from the tracking system is defined and controlled by a H ∞ control to obtain the asymptotical stability and noise resistance. Secondly, by making use of a Lyapunov function and the norm boundedness, a new robust control with the “Leitmann approach” is designed to cope with the uncertainty. The two controls collaborate with each other to achieve “uniform tracking boundedness” and “uniform ultimate tracking boundedness”. The new approach is then applied to an aircraft turbofan control design, and the numerical simulation results show the prescribed performances of the closed-loop system and the advantage of the developed approach.

  2. Numerical Investigation of the Influence of the Input Air Irregularity on the Performance of Turbofan Jet Engine

    Science.gov (United States)

    Novikova, Y.; Zubanov, V.

    2018-01-01

    The article describes the numerical investigation of the input air irregularity influence of turbofan engine on its characteristics. The investigated fan has a wide-blade, an inlet diameter about 2 meters, a pressure ratio about 1.6 and the bypass ratio about 4.8. The flow irregularity was simulated by the flap input in the fan inlet channel. Input of flap was carried out by an amount of 10 to 22,5% of the input channel diameter with increments of 2,5%. A nonlinear harmonic analysis (NLH-analysis) of NUMECA Fine/Turbo software was used to study the flow irregularity. The behavior of the calculated LPC characteristics repeats the experiment behavior, but there is a quantitative difference: the calculated efficiency and pressure ratio of booster consistent with the experimental data within 3% and 2% respectively, the calculated efficiency and pressure ratio of fan duct - within 4% and 2.5% respectively. An increasing the level of air irregularity in the input stage of the fan reduces the calculated mass flow, maximum pressure ratio and efficiency. With the value of flap input 12.5%, reducing the maximum air flow is 1.44%, lowering the maximum pressure ratio is 2.6%, efficiency decreasing is 3.1%.

  3. Acoustic Diagnostics of Turbofan Health Monitoring

    Data.gov (United States)

    National Aeronautics and Space Administration — This unique innovation employs an array of external microphones to pinpoint faults within turbofan engines. The development team partnered with Armstrong’s Vehicle...

  4. 75 FR 51659 - Airworthiness Directives; Pratt & Whitney Canada Corp. PW617F-E Turbofan Engines

    Science.gov (United States)

    2010-08-23

    ... showed that the Fuel Filter Bypass Valve poppet in the Fuel Oil Heat Exchanger (FOHE) on that engine had... that the Fuel Filter Bypass Valve poppet in the FOHE on that engine had worn through the housing seat... of the FOHE fuel filter bypass valve on all PW617F-E engines as per Pratt & Whitney Canada Corp. ASB...

  5. 75 FR 27489 - Airworthiness Directives; Pratt & Whitney Canada Corp. PW615F-A Turbofan Engines

    Science.gov (United States)

    2010-05-17

    .... Investigation showed that the Fuel Filter Bypass Valve poppet in the Fuel Oil Heat Exchanger (FOHE) on that...-A engine Fuel Filter Bypass Valve is very similar to that of PW617F-E, but so far there have been no... Fuel Filter Bypass Valve poppet in the FOHE on that engine had worn through the housing seat, allowing...

  6. 75 FR 27491 - Airworthiness Directives; Pratt & Whitney Canada Corp. PW617F-E Turbofan Engines

    Science.gov (United States)

    2010-05-17

    .... Investigation showed that the Fuel Filter Bypass Valve poppet in the Fuel Oil Heat Exchanger (FOHE) on that... Fuel Filter Bypass Valve poppet in the FOHE on that engine had worn through the housing seat, allowing... FOHE fuel filter bypass valve on all PW617F-E engines as per Pratt & Whitney Canada Corp. ASB No. PW600...

  7. Collaboration with Williams International to Demonstrate the Characteristics of a Foam-Metal-Liner Installed Over-the-Rotor of a Turbofan Engine

    Science.gov (United States)

    Sutliff, Daniel; Elliott, Dave; Jones, Mike; Hartley, Tom

    2008-01-01

    A Williams International FJ44-3A 3000-lb thrust class turbofan engine was used as a demonstrator for foam-metal liner installed in close proximity to the fan. Two foam metal liner designs were tested and compared to the hardwall. Traditional Single-Degree-of-Freedom liner designs were also evaluated to provide a comparison. Normalized information on farfield acoustics is presented in this paper. The results show that up to 5 dB PWL overall attenuation was achieved in the forward quadrant. In general, the foam-metal liners performed better when the fan tip speed was below sonic.

  8. 78 FR 48339 - Airworthiness Directives; Rolls-Royce Corporation Turbofan Engines

    Science.gov (United States)

    2013-08-08

    ... replaced during engine shop visit at no additional labor cost. Based on these figures, we estimate the... maintain their existing approved life limits. (d) Unsafe Condition This AD was prompted by stress and...

  9. Continuous-Scan Phased Array Measurement Methods for Turbofan Engine Acoustic Testing, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — ATA Engineering, Inc., (ATA) proposes an SBIR project to advance the technology readiness level (TRL) of a method for measuring phased array acoustic data for...

  10. Continuous-Scan Phased Array Measurement Methods for Turbofan Engine Acoustic Testing, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — To allow aviation growth to continue in the face of increasingly stringent noise pollution standards, new aircraft engines must be designed with noise performance as...

  11. Parallel Hybrid Gas-Electric Geared Turbofan Engine Conceptual Design and Benefits Analysis

    Science.gov (United States)

    Lents, Charles; Hardin, Larry; Rheaume, Jonathan; Kohlman, Lee

    2016-01-01

    The conceptual design of a parallel gas-electric hybrid propulsion system for a conventional single aisle twin engine tube and wing vehicle has been developed. The study baseline vehicle and engine technology are discussed, followed by results of the hybrid propulsion system sizing and performance analysis. The weights analysis for the electric energy storage & conversion system and thermal management system is described. Finally, the potential system benefits are assessed.

  12. 78 FR 2197 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines

    Science.gov (United States)

    2013-01-10

    ... AD requires a one-time inspection of the low-pressure compressor (LPC) fan blades and if erosion is... edge erosion of the LPC fan blades on certain Tay 620-15 engines. We are issuing this AD to prevent... evidence of excessive leading edge erosion. Excessive material removal during the maintenance reduces the...

  13. 78 FR 70489 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2013-11-26

    ... cycles since last leading edge profile blade repair (FCSLR). This AD was prompted by reports of erosion... specified products. The MCAI states: Erosion of the leading edge profile of Trent 500 engines' low pressure... erosion of the leading edge profile of the low-pressure (LP) compressor blade set contributing to fan...

  14. 78 FR 20507 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2013-04-05

    ..., business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal... carried out by Rolls-Royce revealed changes to the thermal profile and stresses in certain features of the... engines installed on airplanes of U.S. registry. The average labor rate is $85 per hour. We do not...

  15. 77 FR 12444 - Airworthiness Directives; General Electric Company (GE) Turbofan Engines

    Science.gov (United States)

    2012-03-01

    ... failure of the high-pressure compressor (HPC) rotor or the low-pressure turbine (LPT) rotor, or both... Estimate Commenter Atlas Air requested that we revise the cost estimate by including cost to replace LLPs...-conforming packings for these engines. Commenter Atlas Air commented that applicability should only apply to...

  16. 75 FR 31330 - Airworthiness Directives; Pratt & Whitney PW4000 Series Turbofan Engines

    Science.gov (United States)

    2010-06-03

    ... bearing oil pressure tubes found cracked that led to unscheduled engine removals, and one report of a test... Web site, anyone can find and read the comments in any of our dockets, including, if provided, the... bearing oil pressure tube, and that the tube was previously weld- repaired. That fire led to failure of...

  17. Fluctuating pressures on fan blades of a turbofan engine, flight test investigation

    Science.gov (United States)

    Schoenster, J. A.

    1985-01-01

    Miniature pressure transducers were used to measure the fluctuating pressure on the fan blades of a JT15D engine in flight to aid in understanding fan-noise generation. Although the blade pressures can be considered very useful in determining far-field noise sources in the subsonic fan-blade tip speeds, other mechanisms, and as shock waves in the transonic and supersonic fan-blade tip speeds, limit their usefulness in these higher speed ranges.

  18. Extending the Operational Envelope of a Turbofan Engine Simulation into the Sub-Idle Region

    Science.gov (United States)

    Chapman, Jeffryes Walter; Hamley, Andrew J.; Guo, Ten-Huei; Litt, Jonathan S.

    2016-01-01

    In many non-linear gas turbine simulations, operation in the sub-idle region can lead to model instability. This paper lays out a method for extending the operational envelope of a map based gas turbine simulation to include the sub-idle region. This method develops a multi-simulation solution where the baseline component maps are extrapolated below the idle level and an alternate model is developed to serve as a safety net when the baseline model becomes unstable or unreliable. Sub-idle model development takes place in two distinct operational areas, windmilling/shutdown and purge/cranking/startup. These models are based on derived steady state operating points with transient values extrapolated between initial (known) and final (assumed) states. Model transitioning logic is developed to predict baseline model sub-idle instability, and transition smoothly and stably to the backup sub-idle model. Results from the simulation show a realistic approximation of sub-idle behavior as compared to generic sub-idle engine performance that allows the engine to operate continuously and stably from shutdown to full power.

  19. Development of a Twin-Spool Turbofan Engine Simulation Using the Toolbox for the Modeling and Analysis of Thermodynamic Systems (T-MATS)

    Science.gov (United States)

    Zinnecker, Alicia M.; Chapman, Jeffryes W.; Lavelle, Thomas M.; Litt, Jonathan S.

    2014-01-01

    The Toolbox for the Modeling and Analysis of Thermodynamic Systems (T-MATS) is a tool that has been developed to allow a user to build custom models of systems governed by thermodynamic principles using a template to model each basic process. Validation of this tool in an engine model application was performed through reconstruction of the Commercial Modular Aero-Propulsion System Simulation (C-MAPSS) (v2) using the building blocks from the T-MATS (v1) library. In order to match the two engine models, it was necessary to address differences in several assumptions made in the two modeling approaches. After these modifications were made, validation of the engine model continued by integrating both a steady-state and dynamic iterative solver with the engine plant and comparing results from steady-state and transient simulation of the T-MATS and C-MAPSS models. The results show that the T-MATS engine model was accurate within 3% of the C-MAPSS model, with inaccuracy attributed to the increased dimension of the iterative solver solution space required by the engine model constructed using the T-MATS library. This demonstrates that, given an understanding of the modeling assumptions made in T-MATS and a baseline model, the T-MATS tool provides a viable option for constructing a computational model of a twin-spool turbofan engine that may be used in simulation studies.

  20. Development of a Twin-spool Turbofan Engine Simulation Using the Toolbox for Modeling and Analysis of Thermodynamic Systems (T-MATS)

    Science.gov (United States)

    Zinnecker, Alicia M.; Chapman, Jeffryes W.; Lavelle, Thomas M.; Litt, Johathan S.

    2014-01-01

    The Toolbox for Modeling and Analysis of Thermodynamic Systems (T-MATS) is a tool that has been developed to allow a user to build custom models of systems governed by thermodynamic principles using a template to model each basic process. Validation of this tool in an engine model application was performed through reconstruction of the Commercial Modular Aero-Propulsion System Simulation (C-MAPSS) (v2) using the building blocks from the T-MATS (v1) library. In order to match the two engine models, it was necessary to address differences in several assumptions made in the two modeling approaches. After these modifications were made, validation of the engine model continued by integrating both a steady-state and dynamic iterative solver with the engine plant and comparing results from steady-state and transient simulation of the T-MATS and C-MAPSS models. The results show that the T-MATS engine model was accurate within 3 of the C-MAPSS model, with inaccuracy attributed to the increased dimension of the iterative solver solution space required by the engine model constructed using the T-MATS library. This demonstrates that, given an understanding of the modeling assumptions made in T-MATS and a baseline model, the T-MATS tool provides a viable option for constructing a computational model of a twin-spool turbofan engine that may be used in simulation studies.

  1. Separating Direct and Indirect Turbofan Engine Combustion Noise While Estimating Post-Combustion (Post-Flame) Residence Time Using the Correlation Function

    Science.gov (United States)

    Miles, Jeffrey Hilton

    2011-01-01

    A previous investigation on the presence of direct and indirect combustion noise for a full-scale turbofan engine using a far-field microphone at 130 is extended by also examining signals obtained at two additional downstream directions using far-field microphones at 110 deg and 160 deg. A generalized cross-correlation function technique is used to study the change in propagation time to the far field of the combined direct and indirect combustion noise signal as a sequence of low-pass filters are applied. The filtering procedure used produces no phase distortion. As the low-pass filter frequency is decreased, the travel time increases because the relative amount of direct combustion noise is reduced. The indirect combustion noise signal travels more slowly because in the combustor entropy fluctuations move with the flow velocity, which is slow compared to the local speed of sound. The indirect combustion noise signal travels at acoustic velocities after reaching the turbine and being converted into an acoustic signal. The direct combustion noise is always propagating at acoustic velocities. The results show that the estimated indirect combustion noise time delay values (post-combustion residence times) measured at each angle are fairly consistent with one another for a relevant range of operating conditions and demonstrate source separation of a mixture of direct and indirect combustion noise. The results may lead to a better idea about the acoustics in the combustor and may help develop and validate improved reduced-order physics-based methods for predicting turbofan engine core noise.

  2. Fundamentals of Structural Engineering

    CERN Document Server

    Connor, Jerome J

    2013-01-01

    Fundamentals of Structural Engineering provides a balanced, seamless treatment of both classic, analytic methods and contemporary, computer-based techniques for conceptualizing and designing a structure. The book’s principle goal is to foster an intuitive understanding of structural behavior based on problem solving experience for students of civil engineering and architecture who have been exposed to the basic concepts of engineering mechanics and mechanics of materials. Making it distinct from many other undergraduate textbooks, the authors of this text recognize the notion that engineers reason about behavior using simple models and intuition they acquire through problem solving. The approach adopted in this text develops this type of intuition  by presenting extensive, realistic problems and case studies together with computer simulation, which allows rapid exploration of  how a structure responds to changes in geometry and physical parameters. This book also: Emphasizes problem-based understanding of...

  3. Advanced structural wind engineering

    CERN Document Server

    Kareem, Ahsan

    2013-01-01

    This book serves as a textbook for advanced courses as it introduces state-of-the-art information and the latest research results on diverse problems in the structural wind engineering field. The topics include wind climates, design wind speed estimation, bluff body aerodynamics and applications, wind-induced building responses, wind, gust factor approach, wind loads on components and cladding, debris impacts, wind loading codes and standards, computational tools and computational fluid dynamics techniques, habitability to building vibrations, damping in buildings, and suppression of wind-induced vibrations. Graduate students and expert engineers will find the book especially interesting and relevant to their research and work.

  4. Structural motion engineering

    CERN Document Server

    Connor, Jerome

    2014-01-01

    This innovative volume provides a systematic treatment of the basic concepts and computational procedures for structural motion design and engineering for civil installations. The authors illustrate the application of motion control to a wide spectrum of buildings through many examples. Topics covered include optimal stiffness distributions for building-type structures, the role of damping in controlling motion, tuned mass dampers, base isolation systems, linear control, and nonlinear control. The book's primary objective is the satisfaction of motion-related design requirements, such as restrictions on displacement and acceleration. The book is ideal for practicing engineers and graduate students. This book also: ·         Broadens practitioners' understanding of structural motion control, the enabling technology for motion-based design ·         Provides readers the tools to satisfy requirements of modern, ultra-high strength materials that lack corresponding stiffness, where the motion re...

  5. 76 FR 70382 - Airworthiness Directives; General Electric Company (GE) CF6-80C2B Series Turbofan Engines

    Science.gov (United States)

    2011-11-14

    ... installing software version 8.2.Q1 to the engine electronic control unit (ECU), which increases the engine's... software version 8.2.Q1 to the ECU, which increases the engine's margin to flameout. That AD was prompted by multiple reports of flameout events during flight on engines with an ECU software version...

  6. A Method to Predict Compressor Stall in the TF34-100 Turbofan Engine Utilizing Real-Time Performance Data

    Science.gov (United States)

    2015-06-01

    pass turbo –fan engine sensor data to seek its deterioration modelling and prognostics capability. In futurity this will allow for achievement of...preventive maintenance for the TF34-100 jet engine to prevent engine compressor stalls for the A-10 aircraft. Due to their destructive nature, compressor...stalls are a significant concern in axial flow compressor jet engines. A compressor stall is caused by air approaching the compressor blades at an

  7. 75 FR 51657 - Airworthiness Directives; Pratt & Whitney Canada Corp. (P&WC) PW615F-A Turbofan Engines

    Science.gov (United States)

    2010-08-23

    ... showed that the Fuel Filter Bypass Valve poppet in the Fuel Oil Heat Exchanger (FOHE) on that engine had... that the Fuel Filter Bypass Valve poppet in the Fuel Oil Heat Exchanger (FOHE) on that engine had worn... a dormant failure that could result in an unsafe condition. The PW615F-A engine Fuel Filter Bypass...

  8. Noise-Source Separation Using Internal and Far-Field Sensors for a Full-Scale Turbofan Engine

    Science.gov (United States)

    Hultgren, Lennart S.; Miles, Jeffrey H.

    2009-01-01

    Noise-source separation techniques for the extraction of the sub-dominant combustion noise from the total noise signatures obtained in static-engine tests are described. Three methods are applied to data from a static, full-scale engine test. Both 1/3-octave and narrow-band results are discussed. The results are used to assess the combustion-noise prediction capability of the Aircraft Noise Prediction Program (ANOPP). A new additional phase-angle-based discriminator for the three-signal method is also introduced.

  9. 76 FR 14797 - Airworthiness Directives; Rolls-Royce plc (RR) RB211-Trent 900 Series Turbofan Engines

    Science.gov (United States)

    2011-03-18

    ...: Discussion The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of... Protection System (IPTOS). The purpose of the IPTOS functionality is to detect engine conditions that may.... Applicability (c) This AD applies to RR model RB211-Trent 970-84, 970B-84, 972-84, 972B-84, 977-84, 977B-84, and...

  10. Quiet Clean General Aviation Turbofan (QCGAT) technology study, volume 1

    Science.gov (United States)

    1975-01-01

    The preliminary design of an engine which satisfies the requirements of a quiet, clean, general aviation turbofan (QCGAT) engine is described. Also an experimental program to demonstrate performance is suggested. The T700 QCGAT engine preliminary design indicates that it will radiate noise at the same level as an aircraft without engine noise, have exhaust emissions within the EPA 1981 Standards, have lower fuel consumption than is available in comparable size engines, and have sufficient life for five years between overhauls.

  11. Acoustic Detection of Faults and Degradation in a High-Bypass Turbofan Engine during VIPR Phase III Testing

    Science.gov (United States)

    Boyle, Devin K.

    2017-01-01

    The Vehicle Integrated Propulsion Research (VIPR) Phase III project was executed at Edwards Air Force Base, California, by the National Aeronautics and Space Administration and several industry, academic, and government partners in the summer of 2015. One of the research objectives was to use external radial acoustic microphone arrays to detect changes in the noise characteristics produced by the research engine during volcanic ash ingestion and seeded fault insertion scenarios involving bleed air valves. Preliminary results indicate the successful acoustic detection of suspected degradation as a result of cumulative exposure to volcanic ash. This detection is shown through progressive changes, particularly in the high-frequency content, as a function of exposure to greater cumulative quantities of ash. Additionally, detection of the simulated failure of the 14th stage stability bleed valve and, to a lesser extent, the station 2.5 stability bleed valve, to their fully-open fail-safe positions was achieved by means of spectral comparisons between nominal (normal valve operation) and seeded fault scenarios.

  12. The science of structural engineering

    CERN Document Server

    Heyman, Jacques

    1999-01-01

    Structures cannot be created without engineering theory, and design rules have existed from the earliest times for building Greek temples, Roman aqueducts and Gothic cathedrals - and later, for steel skyscrapers and the frames for aircraft. This book is, however, not concerned with the description of historical feats, but with the way the structural engineer sets about his business. Galileo, in the seventeenth century, was the first to introduce recognizably modern science into the calculation of structures; he determined the breaking strength of beams. In the eighteenth century engineers move

  13. 9th Structural Engineering Convention 2014

    CERN Document Server

    2015-01-01

    The book presents research papers presented by academicians, researchers, and practicing structural engineers from India and abroad in the recently held Structural Engineering Convention (SEC) 2014 at Indian Institute of Technology Delhi during 22 – 24 December 2014. The book is divided into three volumes and encompasses multidisciplinary areas within structural engineering, such as earthquake engineering and structural dynamics, structural mechanics, finite element methods, structural vibration control, advanced cementitious and composite materials, bridge engineering, and soil-structure interaction. Advances in Structural Engineering is a useful reference material for structural engineering fraternity including undergraduate and postgraduate students, academicians, researchers and practicing engineers.

  14. Crystal engineering: structure, property and beyond

    OpenAIRE

    Desiraju, Gautam R.

    2017-01-01

    Crystal engineering, which was considered to be crystal structure engineering, is now transforming into crystal property engineering. The same or similar crystal structures could have different properties while different crystal structures could have similar properties.

  15. Engineered bamboo for shell structures

    OpenAIRE

    Sharma, B; Konstantatou, Marina; Reynolds, M; Ramage, M

    2015-01-01

    Engineered bamboo combines the benefits of a natural material with the advantages of a laminated composite, resulting in an efficient, light material well-suited to gridshell structures. Bamboo is a rapidly renewable material that can be harvested every 4-5 years. The round culm can either be used as is or it can be processed into a variety of laminated products. Engineered bamboo is currently promoted as a structural alternative to timber and glue-laminated timber, but also has potential in ...

  16. Structural health monitoring on turbine engines using microwave blade tip clearance sensors

    Science.gov (United States)

    Woike, Mark; Abdul-Aziz, Ali; Clem, Michelle

    2014-04-01

    The ability to monitor the structural health of the rotating components, especially in the hot sections of turbine engines, is of major interest to the aero community in improving engine safety and reliability. The use of instrumentation for these applications remains very challenging. It requires sensors and techniques that are highly accurate, are able to operate in a high temperature environment, and can detect minute changes and hidden flaws before catastrophic events occur. The National Aeronautics and Space Administration (NASA) has taken a lead role in the investigation of new sensor technologies and techniques for the in situ structural health monitoring of gas turbine engines. As part of this effort, microwave sensor technology has been investigated as a means of making high temperature non-contact blade tip clearance, blade tip timing, and blade vibration measurements for use in gas turbine engines. This paper presents a summary of key results and findings obtained from the evaluation of two different types of microwave sensors that have been investigated for possible use in structural health monitoring applications. The first is a microwave blade tip clearance sensor that has been evaluated on a large scale Axial Vane Fan, a subscale Turbofan, and more recently on sub-scale turbine engine like disks. The second is a novel microwave based blade vibration sensor that was also used in parallel with the microwave blade tip clearance sensors on the same experiments with the sub-scale turbine engine disks.

  17. Engineering Design of KSTAR tokamak main structure

    International Nuclear Information System (INIS)

    Im, K.H.; Cho, S.; Her, N.I.

    2001-01-01

    The main components of the KSTAR (Korea Superconducting Tokamak Advanced Research) tokamak including vacuum vessel, plasma facing components, cryostat, thermal shield and magnet supporting structure are in the final stage of engineering design. Hundai Heavy Industries (HHI) has been involved in the engineering design of these components. The current configuration and the final engineering design results for the KSTAR main structure are presented. (author)

  18. Architectural Engineering to Super-Light Structures

    DEFF Research Database (Denmark)

    Castberg, Niels Andreas

    The increasing global urbanisation creates a great demand for new buildings. In the aim to honour this, a new structural system, offering flexibility and variation at no extra cost appears beneficial. Super-Light Structures constitute such a system. This PhD thesis examines Super-Light Structures...... with architectural engineering as a starting point. The thesis is based on a two stringed hypothesis: Architectural engineering gives rise to better architecture and Super-Light Structures support and enables a static, challenging architecture. The aim of the thesis is to clarify architectural engineering's impact...... on the work process between architects and engineers in the design development. Using architectural engineering, Super-Light Structures are examined in an architectural context, and it is explained how digital tools can support architectural engineering and design of Super-Light Structures. The experiences...

  19. Engineered Magnetic Core-Shell Structures.

    Science.gov (United States)

    Alavi Nikje, Mir Mohammad; Vakili, Maryam

    2015-01-01

    In recent years, engineered magnetic core-shell structures are playing an important role in the wide range of various applications. These magnetic core-shell structures have attracted considerable attention because of their unique properties and various applications. Also, the synthesis of engineered magnetic core-shell structures has attracted practical interest because of potential applications in areas such as ferrofluids, medical imaging, drug targeting and delivery, cancer therapy, separations, and catalysis. So far a large number of engineered magnetic core-shell structures have been successfully synthesized. This review article focuses on the recent progress in synthesis and characterization of engineered magnetic core-shell structures. Also, this review gives a brief description of the various application of these structures. It is hoped that this review will play some small part in helping future developments in important field.

  20. GETRAN: A generic, modularly structured computer code for simulation of dynamic behavior of aero- and power generation gas turbine engines

    Science.gov (United States)

    Schobeiri, M. T.; Attia, M.; Lippke, C.

    1994-07-01

    The design concept, the theoretical background essential for the development of the modularly structured simulation code GETRAN, and several critical simulation cases are presented in this paper. The code being developed under contract with NASA Lewis Research Center is capable of simulating the nonlinear dynamic behavior of single- and multispool core engines, turbofan engines, and power generation gas turbine engines under adverse dynamic operating conditions. The modules implemented into GETRAN correspond to components of existing and new-generation aero- and stationary gas turbine engines with arbitrary configuration and arrangement. For precise simulation of turbine and compressor components, row-by-row diabatic and adiabatic calculation procedures are implemented that account for the specific turbine and compressor cascade, blade geometry, and characteristics. The nonlinear, dynamic behavior of the subject engine is calculated solving a number of systems of partial differential equations, which describe the unsteady behavior of each component individually. To identify each differential equation system unambiguously, special attention is paid to the addressing of each component. The code is capable of executing the simulation procedure at four levels, which increase with the degree of complexity of the system and dynamic event. As representative simulations, four different transient cases with single- and multispool thrust and power generation engines were simulated. These transient cases vary from throttling the exit nozzle area, operation with fuel schedule, rotor speed control, to rotating stall and surge.

  1. Engine mounts and structural joints

    Indian Academy of Sciences (India)

    While finite element (FEM) solutions are useful if. SaÅdhanaÅ, Vol. 25, Part 3, June 2000, pp. ... A more general set of analysis tools and design dynamics is required to understand existing ... and highly damped to control the idle shake and engine mounting resonance over 5±30 Hz. Also, it must be able to control, like a ...

  2. Vibrational Based Inspection of Civil Engineering Structures

    DEFF Research Database (Denmark)

    Rytter, Anders

    and Structural Engineering at the University of Aalborg since the beginning of 1992. Both projects have been supported by the Danish Technical Research Council. Further, the first mentioned project was supported by the Danish Energy Agency. Their financial support is gratefully acknowledged.......The thesis has been written in relation to two different research projects. Firstly, an offshore test programme, Integrated Experimental/Numerical Analysis of the Dynamic behavior of offshore structures, which was performed at the department of Building Technology and Structural Engineering...... at the University of Aalborg from 1988 to 1991. Secondly, a research project, In-Field Vibration Based Inspection of Civil Engineering Structures, which has been performed as a pilot project by the Consulting Engineers Rambøll, Hannemann and Højlund in cooperation with the department of Building Technology...

  3. Advanced finite element method in structural engineering

    CERN Document Server

    Long, Yu-Qiu; Long, Zhi-Fei

    2009-01-01

    This book systematically introduces the research work on the Finite Element Method completed over the past 25 years. Original theoretical achievements and their applications in the fields of structural engineering and computational mechanics are discussed.

  4. Steels from materials science to structural engineering

    CERN Document Server

    Sha, Wei

    2013-01-01

    Steels and computer-based modelling are fast growing fields in materials science as well as structural engineering, demonstrated by the large amount of recent literature. Steels: From Materials Science to Structural Engineering combines steels research and model development, including the application of modelling techniques in steels.  The latest research includes structural engineering modelling, and novel, prototype alloy steels such as heat-resistant steel, nitride-strengthened ferritic/martensitic steel and low nickel maraging steel.  Researchers studying steels will find the topics vital to their work.  Materials experts will be able to learn about steels used in structural engineering as well as modelling and apply this increasingly important technique in their steel materials research and development. 

  5. Optimal Vibration Control of Civil Engineering Structures

    DEFF Research Database (Denmark)

    Thesbjerg, Leo

    In designing large civil engineering structures, an important consideration is prospective dynamic loadings which may include earthquake ground motion, wind gusts, severe sea states and moving vehicles, rotating and reciprocating machinery and others. successful design of such structures requires...... providing for the safety and integrity of the structure, and in some cases also providing for a measure of comfort for the occupants during such loading which the structure and its occupants must endure. Due to these uncertainties, the civil engineering community has traditionally adopted a very...

  6. Tripartite Essentials of Contemporary Structural Engineering ...

    African Journals Online (AJOL)

    Nekky Umera

    contemporary structural engineer and the shift his education must accommodate in order for his relevance not to ... Keywords: Analysis, Design, Modeling, Structural Behaviour,. Control, Approximate Methods. ..... masonry and the tributary floor areas on columns are not great (small slab panel areas) often have about the ...

  7. Reliability-Based Optimization in Structural Engineering

    DEFF Research Database (Denmark)

    Enevoldsen, I.; Sørensen, John Dalsgaard

    1994-01-01

    In this paper reliability-based optimization problems in structural engineering are formulated on the basis of the classical decision theory. Several formulations are presented: Reliability-based optimal design of structural systems with component or systems reliability constraints, reliability-b...

  8. Internal combustion engine and piston structure therefore

    Energy Technology Data Exchange (ETDEWEB)

    Falero, A.

    1989-09-12

    This patent describes a reciprocating internal combustion engine. It comprises: an engine block; at least one pair of coaxially aligned cylinders in the engine block; a dual-headed piston body comprising first and second piston heads attached to opposite ends of a central yoke structure. The first and second piston heads being adapted to reciprocate within respective cylinders of the pair of cylinders; a roller gear mounted within the yoke structure for rectilinear movement with respect to the yoke structure. The roller gear being engageable with a crankshaft drive gear; control means and actuator means for effecting synchronized movement of the roller gear within the yoke structure to maintain constant engagement of the roller gear with the crankshaft drive gear as the dual headed piston body reciprocates within respective cylinders of the pair of cylinders.

  9. Advanced ceramic in structural engineering

    OpenAIRE

    Alonso Rodea, Jorge

    2012-01-01

    The work deals with "Advanced Ceramics in Structural Engineering”. Throughout this work we present the different types of ceramic that are currently in wider use, and the main research lines that are being followed. Ceramics have very interesting properties, both mechanical and electrical and refractory where we can find some of the most interesting points of inquiry. Through this work we try tounderstand this complex world, analyzing both general and specific properties of ...

  10. High temperature turbine engine structure

    Energy Technology Data Exchange (ETDEWEB)

    Carruthers, W.D.; Boyd, G.L.

    1993-07-20

    A hybrid ceramic/metallic gas turbine is described comprising; a housing defining an inlet, an outlet, and a flow path communicating the inlet with the outlet for conveying a flow of fluid through the housing, a rotor member journaled by the housing in the flow path, the rotor member including a compressor rotor portion rotatively inducting ambient air via the inlet and delivering this air pressurized to the flow path downstream of the compressor rotor, a combustor disposed in the flow path downstream of the compressor receiving the pressurized air along with a supply of fuel to maintain combustion providing a flow of high temperature pressurized combustion products in the flow path downstream thereof, the rotor member including a turbine rotor portion disposed in the flow path downstream of the combustor and rotatively expanding the combustion products toward ambient for flow from the turbine engine via the outlet, the turbine rotor portion providing shaft power driving the compressor rotor portion and an output shaft portion of the rotor member, a disk-like metallic housing portion journaling the rotor member to define a rotational axis therefore, and a disk-like annular ceramic turbine shroud member bounding the flow path downstream of the combustor and circumscribing the turbine rotor portion to define a running clearance therewith, the disk-like ceramic turbine shroud member having a reference axis coaxial with the rotational axis and being spaced axially from the metallic housing portion in mutually parallel concentric relation therewith and a plurality of spacers disposed between ceramic disk-like shroud member and the metallic disk-like housing portion and circumferentially spaced apart, each of the spacers having a first and second end portion having an end surface adjacent the shroud member and the housing portion respectively, the end surfaces having a cylindrical curvature extending transversely relative to the shroud member and the housing portion.

  11. 76 FR 52213 - Airworthiness Directives; General Electric Company (GE) CF6-45 Series and CF6-50 Series Turbofan...

    Science.gov (United States)

    2011-08-22

    ... visit is the induction of an engine into the shop for maintenance involving the separation of the... frame. (2) An engine shop visit is the induction of an engine into the shop for maintenance involving... Directives; General Electric Company (GE) CF6-45 Series and CF6-50 Series Turbofan Engines AGENCY: Federal...

  12. Structures of engineered Clostridium botulinum neurotoxin derivatives

    International Nuclear Information System (INIS)

    Masuyer, Geoffrey; Stancombe, Patrick; Chaddock, John A.; Acharya, K. Ravi

    2011-01-01

    The crystal structures of engineered C. botulinum neurotoxin–SNARE derivatives have been and exhibit strong stability of the LHn fragment. Targeted secretion inhibitors (TSIs) are a new class of engineered biopharmaceutical molecules derived from the botulinum neurotoxins (BoNTs). They consist of the metalloprotease light chain (LC) and translocation domain (Hn) of BoNT; they thus lack the native toxicity towards motor neurons but are able to target soluble N-ethylmaleimide-sensitive fusion protein attachment receptor (SNARE) proteins. These functional fragment (LHn) derivatives are expressed as single-chain proteins and require post-translational activation into di-chain molecules for function. A range of BoNT derivatives have been produced to demonstrate the successful use of engineered SNARE substrate peptides at the LC–Hn interface that gives these molecules self-activating capabilities. Alternatively, recognition sites for specific exoproteases can be engineered to allow controlled activation. Here, the crystal structures of three LHn derivatives are reported between 2.7 and 3.0 Å resolution. Two of these molecules are derivatives of serotype A that contain a SNARE peptide. Additionally, a third structure corresponds to LHn serotype B that includes peptide linkers at the exoprotease activation site. In all three cases the added engineered segments could not be modelled owing to disorder. However, these structures highlight the strong interactions holding the LHn fold together despite the inclusion of significant polypeptide sequences at the LC–Hn interface

  13. Turbofan engine degradation simulation data set

    Data.gov (United States)

    National Aeronautics and Space Administration — PHM08 Challenge Dataset is now publicly available at the NASA Prognostics Respository + Download An online evaluation utility is also provided to let users evaluate...

  14. 76 FR 64791 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG (RRD) BR700-710 Series Turbofan...

    Science.gov (United States)

    2011-10-19

    ... Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG (RRD) BR700-710 Series Turbofan Engines AGENCY... data carried out by Rolls-Royce Deutschland has shown that the effect of touch-and-go and overshoot on... service data carried out by Rolls-Royce Deutschland has shown that the effect of touch-and-go and...

  15. 76 FR 39033 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG (RRD) BR700-710 Series Turbofan...

    Science.gov (United States)

    2011-07-05

    ... Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG (RRD) BR700-710 Series Turbofan Engines AGENCY... unsafe condition as: Analysis of service data carried out by Rolls-Royce Deutschland has shown that the... Federal holidays. Fax: (202) 493-2251. Contact Rolls-Royce Deutschland Ltd & Co KG, Eschenweg 11...

  16. 75 FR 21161 - Airworthiness Directives; General Electric Company (GE) CJ610 Series Turbojet Engines and CF700...

    Science.gov (United States)

    2010-04-23

    ... Airworthiness Directives; General Electric Company (GE) CJ610 Series Turbojet Engines and CF700 Series Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: The FAA is adopting a new airworthiness directive (AD) for GE CJ610 series turbojet engines and CF700 turbofan engines...

  17. Turbofan Noise Reduction Associated With Increased Bypass Nozzle Flow

    Science.gov (United States)

    Woodward, Richard P.; Hughes, Christopher E.

    2005-01-01

    An advanced 22-in. scale model turbofan, typical of a current-generation aircraft engine design by GE Aircraft Engines, was tested in NASA Glenn Research Center s 9- by 15- Foot Low-Speed Wind Tunnel to explore the far-field acoustic effects of an increased bypass nozzle area at simulated aircraft speeds of takeoff, approach, and landing. The wind-tunnel-scale model consisted of the bypass stage fan, stators, and nacelle (including the fan exit nozzle) of a typical turbofan. This fan-stage test was part of the NASA Glenn Fan Broadband Source Diagnostic Test, second entry, which acquired aeroacoustic results over a range of test conditions. A baseline nozzle was selected, and the nozzle area was chosen for maximum performance at sea-level conditions. Two additional nozzles were also tested--one with a 5.4-percent increase in nozzle area over the baseline nozzle (sized for design point conditions), corresponding to a 5-percent increase in fan weight flow, and another nozzle with a 10.9-percent increase in nozzle area over the baseline nozzle (sized for maximum weight flow at sea-level conditions), corresponding to a 7.5 percent increase in fan weight flow. Measured acoustic benefits with increased nozzle area were very encouraging, showing overall sound power level reductions of 2 dB or more (left graph) while the stage adiabatic efficiency (right graph) and thrust (final graph) actually increased by several percentage points. These noise-reduction benefits were seen to include both rotor-interaction tones and broadband noise, and were evident throughout the range of measured sideline angles.

  18. Structural Control Systems Implemented in Civil Engineering

    Directory of Open Access Journals (Sweden)

    Cristian Pastia

    2005-01-01

    Full Text Available Over the past three decades, a great interest has been generated by the use of protection systems to mitigate the effects of dynamic environmental hazards on civil engineering structures, such as earthquakes and strong wind. These control systems develop controllable forces to add or dissipate energy in a structure, or both, due to specific devices integrated with sensors, controllers and real – time process to operate. The paper includes the advantages of these technologies consisting of the following sections: 1 represents an introduction, 2 deals with passive control system, 3 regards some control techniques, 4 concerns hybrid control techniques, 5 contains semi – active control techniques, and 6 is dedicated to general conclusions.

  19. Computer graphics in piping structural engineering

    International Nuclear Information System (INIS)

    Revesz, Z.

    1985-01-01

    Computer graphics in piping structural engineering is gaining in popularity. The large number of systems, the growing complexity of the load cases and structure models require human assimilation of large amounts of data. An effort has been made to enlighten evaluation of numerical data and visualize as much of it as possible, thus eliminating a source of error and accelerating analysis/reporting. The product of this effort is PAID, the Piping Analysis and Interactive Design software. While developing PAID, interest has been focused on the acceleration of the work done mainly by PIPESTRESS. Some installed and tested capabilities of PAID are presented in this paper. Examples are given from the graphic output in report form and the conversation necessary to get such is demonstrated. (orig.)

  20. 46 CFR 11.505 - Engineer officer structure.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Engineer officer structure. 11.505 Section 11.505 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY MERCHANT MARINE OFFICERS AND SEAMEN REQUIREMENTS FOR OFFICER ENDORSEMENTS Professional Requirements for Engineer Officer § 11.505 Engineer officer structure...

  1. Ageing in civil engineering materials and structures

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, Jean-Marc [SETEC TPI, Tour Gamma D 58, quai de la Rapee, 75583 Paris (France)

    2005-07-01

    SETEC TPI will address the 'Aging' topic of the Dijon Symposium by talking about: aging in civil engineering materials and structures, prevention of aging phenomena, in-operation monitoring of degradations related to aging and compensatory measures required to maintain a good safety level. Works as the Millau viaduct, the EdF skyscraper at La Defense - Paris, the renovation of the Grand Palais of Paris and special structures with Monaco's floating dam as well as the 'number 10' shaped gateway boat at Marseilles are illustrations for the issues discussed. The durability of civil engineering structures has become a major concern for designers. The Millau viaduct is designed for a service life of 120 years, and the Monaco dam for 100 years. Calculation rules have been evolving toward the incorporation of the concept of life cycle, for example, the Eurocodes 2 rules (reinforced concrete). The talk will expose the factors which are being taken into account to delay aging versus structure types. This part will be focused towards materials and corresponding regulations: - Reinforced concrete (coating of reinforcements, opening of cracks, choice of reinforcement types), BAEL and Eurocodes 2 rules; - Frame steel (protection, sacrificial anode), CM66 and Eurocodes 3 rules. New materials will also be mentioned: - Ultra high-performance fiber/concrete, with the example of CERACEM applied at Millau for the covering of the toll area barrier; - Titanium, which is starting to appear in the building trades, as for instance for the Beijing China Opera House shell. The second part of the talk will be devoted to a specific case namely, the 'number 10' shaped gateway bridge, a prestressed concrete structure immersed in the Port of Marseilles, which will be used to illustrate the aging phenomenon in a corrosive environment. We will focus on the types of inspection series performed by the Autonomous Port Authority of Marseilles to check the behavior of

  2. Finite Element Vibration and Dynamic Response Analysis of Engineering Structures

    Directory of Open Access Journals (Sweden)

    Jaroslav Mackerle

    2000-01-01

    Full Text Available This bibliography lists references to papers, conference proceedings, and theses/dissertations dealing with finite element vibration and dynamic response analysis of engineering structures that were published from 1994 to 1998. It contains 539 citations. The following types of structures are included: basic structural systems; ground structures; ocean and coastal structures; mobile structures; and containment structures.

  3. 77 FR 65823 - Control of Air Pollution From Aircraft and Aircraft Engines; Emission Standards and Test Procedures

    Science.gov (United States)

    2012-10-31

    ... Control of Air Pollution From Aircraft and Aircraft Engines; Emission Standards and Test Procedures... titled ``Table 3 to Sec. 87.23--Tier 6 NO X Standards for New Subsonic Turbofan or Turbojet Engines with... for New Subsonic Turbofan or Turbojet Engines With Rated Output Above 26.7 kN and the rated output (in...

  4. Hard magnetism in structurally engineered silica nanocomposite.

    Science.gov (United States)

    Song, Hyon-Min; Zink, Jeffrey I

    2016-09-21

    Creation of structural complexity by simple experimental control will be an attractive approach for the preparation of nanomaterials, as a classical bottom-up method is supplemented by a more efficient and more direct artificial engineering method. In this study, structural manipulation of MCM-41 type mesoporous silica is investigated by generating and imbedding hard magnetic CoFe2O4 nanoparticles into mesoporous silica. Depending on the heating rate and target temperature, mesoporous silica undergoes a transformation in shape to form hollow silica, framed silica with interior voids, or melted silica with intact mesostructures. Magnetism is governed by the major CoFe2O4 phase, and it is affected by antiferromagnetic hematite (α-Fe2O3) and olivine-type cobalt silicate (Co2SiO4), as seen in its paramagnetic behavior at the annealing temperature of 430 °C. The early formation of Co2SiO4 than what is usually observed implies the effect of the partial substitution of Fe in the sites of Co. Under slow heating (2.5 °C min(-1)) mesostructures are preserved, but with significantly smaller mesopores (d100 = 1.5 nm). In addition, nonstoichiometric CoxFe1-xO with metal vacancies at 600 °C, and spinel Co3O4 at 700 °C accompany major CoFe2O4. The amorphous nature of silica matrix is thought to contribute significantly to these structurally diverse and rich phases, enabled by off-stoichiometry between Si and O, and accelerated by the diffusion of metal cations into SiO4 polyhedra at an elevated temperature.

  5. Molecular structures guide the engineering of chromatin.

    Science.gov (United States)

    Tekel, Stefan J; Haynes, Karmella A

    2017-07-27

    Chromatin is a system of proteins, RNA, and DNA that interact with each other to organize and regulate genetic information within eukaryotic nuclei. Chromatin proteins carry out essential functions: packing DNA during cell division, partitioning DNA into sub-regions within the nucleus, and controlling levels of gene expression. There is a growing interest in manipulating chromatin dynamics for applications in medicine and agriculture. Progress in this area requires the identification of design rules for the chromatin system. Here, we focus on the relationship between the physical structure and function of chromatin proteins. We discuss key research that has elucidated the intrinsic properties of chromatin proteins and how this information informs design rules for synthetic systems. Recent work demonstrates that chromatin-derived peptide motifs are portable and in some cases can be customized to alter their function. Finally, we present a workflow for fusion protein design and discuss best practices for engineering chromatin to assist scientists in advancing the field of synthetic epigenetics. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  6. Aesthetics in the education of civil and structural engineers

    OpenAIRE

    Songel Gonzalez, Juan María

    2013-01-01

    Civil and structural engineers are responsible for the design of large scale public works, but they hardly receive any training in conceptual design or visual education. The paper raises the need to urge an aesthetic education for engineers, in order to develop their perceptive and creative abilities, and presents the experience of the course on Art and Aesthetics in Civil Engineering held at the Universitat Politècnica de València (Spain). The concept of engineering aesthetics...

  7. Engineering Encounters: Building a Spaghetti Structure

    Science.gov (United States)

    Llewellyn, Douglas; Pray, Sandra; DeRose, Rob; Ottman, William

    2016-01-01

    This column presents ideas and techniques to enhance science teaching. In this month's issue an upper elementary Science, technology, engineering, and math (STEM) challenge brings an engineer into the classroom while emphasizing cooperation, communication, and creativity. STEM activities come in various shapes and sizes. Some are quite involved…

  8. Advances in Structural Control in Civil Engineering in China

    OpenAIRE

    Li, Hongnan; Huo, Linsheng

    2010-01-01

    In the recent years, much attention has been paid to the research and development of structural control techniques with particular emphasis on alleviation of wind and seismic responses of buildings and bridges in China. Structural control in civil engineering has been developed from the concept into a workable technology and applied into practical engineering structures. The aim of this paper is to review a state of the art of researches and applications of structural control in civil enginee...

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

    CERN Document Server

    Altenbach, Holm

    2015-01-01

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

  10. Modern earthquake engineering offshore and land-based structures

    CERN Document Server

    Jia, Junbo

    2017-01-01

    This book addresses applications of earthquake engineering for both offshore and land-based structures. It is self-contained as a reference work and covers a wide range of topics, including topics related to engineering seismology, geotechnical earthquake engineering, structural engineering, as well as special contents dedicated to design philosophy, determination of ground motions, shock waves, tsunamis, earthquake damage, seismic response of offshore and arctic structures, spatial varied ground motions, simplified and advanced seismic analysis methods, sudden subsidence of offshore platforms, tank liquid impacts during earthquakes, seismic resistance of non-structural elements, and various types of mitigation measures, etc. The target readership includes professionals in offshore and civil engineering, officials and regulators, as well as researchers and students in this field.

  11. Biomodel Engineering - From Structure to Behavior

    NARCIS (Netherlands)

    Breitling, Rainer; Donaldson, Robin A.; Gilbert, David R.; Heiner, Monika; Priami, C; Breitling, R; Gilbert, D; Heiner, M; Uhrmacher, AM

    2010-01-01

    Biomodel engineering is the science of designing, constructing and analyzing computational models of biological systems. It forms a systematic and powerful extension of earlier mathematical modeling approaches and has recently gained popularity in systems biology and synthetic biology. In this brief

  12. Probability based high temperature engineering creep and structural fire resistance

    CERN Document Server

    Razdolsky, Leo

    2017-01-01

    This volume on structural fire resistance is for aerospace, structural, and fire prevention engineers; architects, and educators. It bridges the gap between prescriptive- and performance-based methods and simplifies very complex and comprehensive computer analyses to the point that the structural fire resistance and high temperature creep deformations will have a simple, approximate analytical expression that can be used in structural analysis and design. The book emphasizes methods of the theory of engineering creep (stress-strain diagrams) and mathematical operations quite distinct from those of solid mechanics absent high-temperature creep deformations, in particular the classical theory of elasticity and structural engineering. Dr. Razdolsky’s previous books focused on methods of computing the ultimate structural design load to the different fire scenarios. The current work is devoted to the computing of the estimated ultimate resistance of the structure taking into account the effect of high temperatur...

  13. M.Sc. in Civil and Structural Engineering

    DEFF Research Database (Denmark)

    This catalogue contains a list of project ideas proposed by the scientific staff at the Department of Civil Engineering, Aalborg University, and a number of companies. Most of the project ideas in this catalogue may form the basis for long and short candidate projects as well as regular 3rd...... semester projects at the M.Sc. programme in Civil and Structural Engineering....

  14. M.Sc. in Civil and Structural Engineering

    DEFF Research Database (Denmark)

    Clausen, Johan

    The report contain a list of project ideas proposed by the scientific staff at the Department of Civil Engineering, Aalborg University, and a number of companies. Most of the project ideas in this catalogue may form the basis for long and short candidate projects as well as regular 3rd semester...... projects at the M.Sc. programme in Civil and Structural Engineering....

  15. Glucoamylase: structure/function relationships, and protein engineering

    DEFF Research Database (Denmark)

    Sauer, J; Sigurskjold, B W; Christensen, U

    2000-01-01

    fundamental structure/function relationships in the binding and catalytic mechanisms. In parallel, issues of relevance for application have been pursued using protein engineering to improve the industrial properties. The present review focuses on recent findings on the catalytic site, mechanism of action......, substrate recognition, the linker region, the multidomain architecture, the engineering of specificity and stability, and roles of individual substrate binding subsites....

  16. M.Sc. in Civil and Structural Engineering

    DEFF Research Database (Denmark)

    The catalogue contain a list of project ideas proposed by the scientific staff at the Department of Civil Engineering, Aalborg University, and a number of companies. Most of the project ideas in this catalogue may form the basis for long and short candidate projects as well as regular 3rd semester...... projects at the M.Sc. programme in Civil and Structural Engineering....

  17. Engineering Structures and Environment During this Fast Changing ...

    African Journals Online (AJOL)

    Advancements in science and technology has resulted in an improved human life style and fashionable engineering structures that have allowed modern engineers to pay less attention to how design codes can be modified in respond to growing changes in climatic conditions. This, together with disproportionate use of ...

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

    Science.gov (United States)

    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.

  19. Reliability-based optimization of engineering structures

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    2008-01-01

    The theoretical basis for reliability-based structural optimization within the framework of Bayesian statistical decision theory is briefly described. Reliability-based cost benefit problems are formulated and exemplitied with structural optimization. The basic reliability-based optimization prob...

  20. Identification of Civil Engineering Structures using Vector ARMA Models

    DEFF Research Database (Denmark)

    Andersen, Palle; Brincker, Rune; Kirkegaard, Poul Henning

    1998-01-01

    This paper describes the work which have been carried out in the project B.1: Damage Detection in Structures under Random Loading. The project is a part of the research programme Dynamics of Structures founded by the Danish Technical Research Council. The planned contents of and the requirements ...... Dept. of Building Technology and Structural Engineering, Aalborg University....

  1. Automated Modal Parameter Estimation of Civil Engineering Structures

    DEFF Research Database (Denmark)

    Andersen, Palle; Brincker, Rune; Goursat, Maurice

    In this paper the problems of doing automatic modal parameter extraction of ambient excited civil engineering structures is considered. Two different approaches for obtaining the modal parameters automatically are presented: The Frequency Domain Decomposition (FDD) technique and a correlation...

  2. CF6 jet engine performance improvement: New fan

    Science.gov (United States)

    Fasching, W. A.

    1980-01-01

    As part of the NASA sponsored engine component improvement program, and fan package was developed to reduce fuel consumption in current CF6 turbofan aircraft engine. The new fan package consist of an improved fan blade, reduced fan tip clearance due to a fan case stiffener, and a smooth fan casing tip shroud. CF6 engine performance and acoustic tests demonstrated the predicted 1.8% improvement in cruise sfc without an increase in engine noise. Power management thrust/fan speed characteristics were defined. Mechanical and structural integrity was demonstrated in model fan rotor photoelastic stress tests, full-size fan blade bench fatigue tests, and CF6 engine bird ingestion, crosswind, and cyclic endurance tests. The fan was certified in the CF6-500c2/E2 engines and is in commerical service on the Boeing 747-200, Douglas DC-10-30, and Atrbus industrie A300B aircraft.

  3. Parameter identification of civil engineering structures

    Science.gov (United States)

    Juang, J. N.; Sun, C. T.

    1980-01-01

    This paper concerns the development of an identification method required in determining structural parameter variations for systems subjected to an extended exposure to the environment. The concept of structural identifiability of a large scale structural system in the absence of damping is presented. Three criteria are established indicating that a large number of system parameters (the coefficient parameters of the differential equations) can be identified by a few actuators and sensors. An eight-bay-fifteen-story frame structure is used as example. A simple model is employed for analyzing the dynamic response of the frame structure.

  4. Nano-Engineered Structural Joints, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A versatile class of high-performance structural joints is proposed where massive interatomic bonds over the large surface areas of nanostructured surfaces...

  5. Nano-Engineered Structural Joints Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A versatile class of high-performance structural joints is proposed where massive interatomic bonds over the large surface areas of nanostructured surfaces...

  6. Full scale technology demonstration of a modern counterrotating unducted fan engine concept. Engine test

    Science.gov (United States)

    1987-01-01

    The Unducted Fan (UDF) engine is an innovative aircraft engine concept based on an ungeared, counterrotating, unducted, ultra-high-bypass turbofan configuration. This engine is being developed to provide a high thrust-to-weight ratio power plant with exceptional fuel efficiency for subsonic aircraft application. This report covers the successful ground testing of this engine. A test program exceeding 100-hr duration was completed, in which all the major goals were achieved. The following accomplishments were demonstrated: (1) full thrust (25,000 lb); (2) full counterrotating rotor speeds (1393+ rpm); (3) low specific fuel consumption (less than 0.24 lb/hr/lb); (4) new composite fan design; (5) counterrotation of structures, turbines, and fan blades; (6) control system; (7) actuation system; and (8) reverse thrust.

  7. Band structure engineered layered metals for low-loss plasmonics

    DEFF Research Database (Denmark)

    Gjerding, Morten Niklas; Pandey, Mohnish; Thygesen, Kristian Sommer

    2017-01-01

    dichalcogenide TaS2, due to an extraordinarily small density of states for scattering in the near-IR originating from their special electronic band structure. On the basis of this observation, we propose a new class of band structure engineered van der Waals layered metals composed of hexagonal transition metal...

  8. Efficient Spatial Data Structure for Multiversion Management of Engineering Drawings

    Directory of Open Access Journals (Sweden)

    Yasuaki Nakamura

    2004-08-01

    Full Text Available In the engineering database system, multiple versions of a design including engineering drawings should be managed efficiently. The paper proposes an extended spatial data structure for efficient management of multiversion engineering drawings. The R-tree is adapted as a basic data structure. The efficient mechanism to manage the difference between drawings is introduced to the R-tree to eliminate redundant duplications and to reduce the amount of storage required for the data structure. The extended data structures of the R-tree, MVR and MVR* trees, are developed and the performances of these trees are evaluated. A series of simulation tests shows that, compared with the basic R-tree, the amounts of storage required for the MVR and MVR* trees are reduced to 50% and 30%, respectively. The search efficiencies of the R, MVR, and MVR* trees are almost the same.

  9. Data structure and software engineering challenges and improvements

    CERN Document Server

    Antonakos, James L

    2011-01-01

    Data structure and software engineering is an integral part of computer science. This volume presents new approaches and methods to knowledge sharing, brain mapping, data integration, and data storage. The author describes how to manage an organization's business process and domain data and presents new software and hardware testing methods. The book introduces a game development framework used as a learning aid in a software engineering at the university level. It also features a review of social software engineering metrics and methods for processing business information. It explains how to

  10. Dismantling of nuclear facilities. From a structural engineering perspective

    International Nuclear Information System (INIS)

    Block, Carsten; Henkel, Fritz-Otto; Bauer, Thomas

    2014-01-01

    The paper summarizes some important aspects, requirements and technical boundary conditions that need to be considered in dismantling projects in the nuclear sector from a structural engineering perspective. Besides general requirements regarding radiation protection, occupational safety, efficiency and cost effectiveness it is important to take into account other conditions which have a direct impact on technical details and the structural assessment of the dismantling project. These are the main aspects highlighted in this paper: - The structural assessment of dismantling projects has to be based on the as-built situation. - The limitations in terms of available equipment and space have to be taken into account. - The structural assessments are often non-standardized engineering evaluations. A selection of five dismantling projects illustrates the various structural aspects. (orig.)

  11. Engineering computation of structures the finite element method

    CERN Document Server

    Neto, Maria Augusta; Roseiro, Luis; Cirne, José; Leal, Rogério

    2015-01-01

    This book presents theories and the main useful techniques of the Finite Element Method (FEM), with an introduction to FEM and many case studies of its use in engineering practice. It supports engineers and students to solve primarily linear problems in mechanical engineering, with a main focus on static and dynamic structural problems. Readers of this text are encouraged to discover the proper relationship between theory and practice, within the finite element method: Practice without theory is blind, but theory without practice is sterile. Beginning with elasticity basic concepts and the classical theories of stressed materials, the work goes on to apply the relationship between forces, displacements, stresses and strains on the process of modeling, simulating and designing engineered technical systems. Chapters discuss the finite element equations for static, eigenvalue analysis, as well as transient analyses. Students and practitioners using commercial FEM software will find this book very helpful. It us...

  12. Deformation compatibility control for engineering structures methods and applications

    CERN Document Server

    Zhu, Hanhua; Chen, Mengchong; Deng, Jianliang

    2017-01-01

    This book presents essential methods of deformation compatibility control, and explicitly addresses the implied conditions on the methods’ deformation compatibility. Consequently, these conditions can be considered in engineering structure design, while the conditions on stable equilibrium can be taken into account in the design method. Thus, the designed deformation and the actual deformation of the respective structure are approximately identical, guaranteeing both the flexibility of the construction material in force transmission and the equilibrium of force in the structure. Though equilibrium theory in engineering structures has been extensively studied, there has been comparatively little research on compatibility. In the limited researches available, the topics are primarily the theories and assumptions on the deformation compatibility, while few systematic works focus on the mechanical theoretical principles and methods of deformation compatibility control. As such, the flexibility of the constructi...

  13. CAL Packages for Civil Engineering Hydraulics and Structural Design.

    Science.gov (United States)

    Moss, W. D.; And Others

    1979-01-01

    Describes computer assisted learning (CAL) packages written in FORTRAN IV and developed for use in a degree course in civil engineering dealing with hydraulics and structures. All are used in the interactive mode through a terminal with a keyboard and visual display unit. (Author/CMV)

  14. State Space identification of Civil Engineering Structures from Output Measurements

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Andersen, P.

    1997-01-01

    for identification of civil engineering structures. The SST is compared with the stochastic realization estimator Matrix Block Hankel (MBH) and a prediction error method (PEM). The results show that the investigated techniques give good results in terms of estimated modal parameters and mode shapes. Especially...

  15. State Space identification of Civil Engineering Structures from Output Measurements

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Andersen, P.

    for identification of civil engineering structures. The SST is compared with the stochastic realization estimator Matrix Block Hankel (MBH) and a prediction error method (PEM). The results show that the investigated techniques give good results in terms of estimated modal parameters and mode shapes. Especially...

  16. "Shell and space structures in modern engineering: Challenges and ...

    African Journals Online (AJOL)

    "Shell and space structures in modern engineering: Challenges and opportunities" - An Inaugural Lecture. A Zingoni. Abstract. An Inaugural Lecture Given in the University of Zimbabwe On 4 July 2001. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  17. Determination of verticality of reservoir engineering structure from ...

    African Journals Online (AJOL)

    Terrestrial laser scanners (TLS) are used nowadays as Geomatics instruments for various applications. One of these applications is 3D survey and management of oil and gas facilities and other engineering structures. This recent attention is due to the fact that laser scanner has the ability to generate massive amounts of ...

  18. A new generation of computational tools in structural engineering

    International Nuclear Information System (INIS)

    Ebersolt, L.; Verpeaux, P.; Farvacque, M.; Combescure, A.

    1985-11-01

    The new concepts of operators and typed objects changed considerably the programming capacities for the finite element method in structural engineering. Their greater versatility offers many advantages: especially the user's capacity to modify or improve an algorithm just by changing the dataset and this without and help from the developping team [fr

  19. Self-stress control of real civil engineering tensegrity structures

    Science.gov (United States)

    Kłosowska, Joanna; Obara, Paulina; Gilewski, Wojciech

    2018-01-01

    The paper introduces the impact of the self-stress level on the behaviour of the tensegrity truss structures. Displacements for real civil engineering tensegrity structures are analysed. Full-scale tensegrity tower Warnow Tower which consists of six Simplex trusses is considered in this paper. Three models consisting of one, two and six modules are analysed. The analysis is performed by the second and third order theory. Mathematica software and Sofistik programme is applied to the analysis.

  20. Modern thermodynamics from heat engines to dissipative structures

    CERN Document Server

    Kondepudi, Dilip

    2014-01-01

    Modern Thermodynamics: From Heat Engines to Dissipative Structures, Second Edition presents a comprehensive introduction to 20th century thermodynamics that can be applied to both equilibrium and non-equilibrium systems, unifying what was traditionally divided into 'thermodynamics' and 'kinetics' into one theory of irreversible processes. This comprehensive text, suitable for introductory as well as advanced courses on thermodynamics, has been widely used by chemists, physicists, engineers and geologists.  Fully revised and expanded, this new edition includes the following updates and featur

  1. First Canadian workshop on engineering structural integrity : CWESI. Proceedings

    International Nuclear Information System (INIS)

    2002-01-01

    The First Canadian Workshop on Engineering Structural Integrity (CWESI) was held on October 16 and 17, 2002, in Toronto, Canada. The purpose of the Workshop was to review strategies for ESI in a number of key industries, and to attempt to plot a course for co-operation in ESI activities and implementation of ESI initiatives in Canadian industry, together with support for appropriate educational, research and development activities. The Workshop consisted of presentations by speakers from a number of industries. Presentations focused on in-service experience under service conditions related to the Canadian environment. This Workshop was attended by practising structural integrity engineers, managers with the responsibility for delivery of safe and reliable operation, and researchers in the structural integrity area

  2. Structurally compliant rocket engine combustion chamber: Experimental and analytical validation

    Science.gov (United States)

    Jankovsky, Robert S.; Arya, Vinod K.; Kazaroff, John M.; Halford, Gary R.

    1994-03-01

    A new, structurally compliant rocket engine combustion chamber design has been validated through analysis and experiment. Subscale, tubular channel chambers have been cyclically tested and analytically evaluated. Cyclic lives were determined to have a potential for 1000 percent increase over those of rectangular channel designs, the current state of the art. Greater structural compliance in the circumferential direction gave rise to lower thermal strains during hot firing, resulting in lower thermal strain ratcheting and longer predicted fatigue lives. Thermal, structural, and durability analyses of the combustion chamber design, involving cyclic temperatures, strains, and low-cycle fatigue lives, have corroborated the experimental observations.

  3. Engineering the Electronic Band Structure for Multiband Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, N.; Reichertz, L.A.; Yu, K.M.; Campman, K.; Walukiewicz, W.

    2010-07-12

    Using the unique features of the electronic band structure of GaNxAs1-x alloys, we have designed, fabricated and tested a multiband photovoltaic device. The device demonstrates an optical activity of three energy bands that absorb, and convert into electrical current, the crucial part of the solar spectrum. The performance of the device and measurements of electroluminescence, quantum efficiency and photomodulated reflectivity are analyzed in terms of the Band Anticrossing model of the electronic structure of highly mismatched alloys. The results demonstrate the feasibility of using highly mismatched alloys to engineer the semiconductor energy band structure for specific device applications.

  4. Cabin-fuselage-wing structural design concept with engine installation

    Science.gov (United States)

    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

  5. Engineering method to build the composite structure ply database

    Directory of Open Access Journals (Sweden)

    Qinghua Shi

    Full Text Available In this paper, a new method to build a composite ply database with engineering design constraints is proposed. This method has two levels: the core stacking sequence design and the whole stacking sequence design. The core stacking sequences are obtained by the full permutation algorithm considering the ply ratio requirement and the dispersion character which characterizes the dispersion of ply angles. The whole stacking sequences are the combinations of the core stacking sequences. By excluding the ply sequences which do not meet the engineering requirements, the final ply database is obtained. One example with the constraints that the total layer number is 100 and the ply ratio is 30:60:10 is presented to validate the method. This method provides a new way to set up the ply database based on the engineering requirements without adopting intelligent optimization algorithms. Keywords: Composite ply database, VBA program, Structure design, Stacking sequence

  6. Fatigue in engineering structures. A three fold analysis approach

    International Nuclear Information System (INIS)

    Malik, Afzaal M.; Qureshi, Ejaz M.; Dar, Naeem Ullah; Khan, Iqbal

    2007-01-01

    The integrity in most of the engineering structures in influenced by the presence of cracks or crack like defects. These structures fail, even catastrophically if a crack greater than a critically safe size exist. Although most of the optimal designed structures are initially free from critical cracks, sub-critical cracks can lead to failures under cyclic loadings, called fatigue crack growth. It is nearly impractical to prevent sub-critical crack growth in engineering structures particularly in crack sensitive structures like most of the structures in nuclear, aerospace and aeronautical domains. However, it is essential to predict the fatigue crack growth for these structures to preclude the in service failures causing loss of assets. The present research presents an automatic procedure for the prediction of fatigue crack growth in three dimensional engineering structures and the key data for the fracture mechanics based design: the stress intensity factors. Three fold analysis procedures are adopted to investigate the effects of repetitive (cyclic) loadings on the fatigue life of different geometries of aluminum alloy 2219-O. A general purpose Finite Element (FE) Code ANSYS-8.0 is used to predict/estimate the fatigue life of the geometries. Computer codes utilizing the Green's Function are developed to calculate the stress intensity factors. Another code based on superposition technique presented by Shivakumara and Foreman is developed to calculate the fatigue crack growth rate, fatigue life (No. of loading cycles are developed to validate the results and finally full scale laboratory tests are conducted for the comparison of the results. The results showing a close co-relation between the different techniques employed gives the promising feature of the analysis approach for the future work. (author)

  7. Impact of the Ownership Structure on Corporate Management in Engineering

    Directory of Open Access Journals (Sweden)

    Dieieva Nataliia E.

    2014-02-01

    Full Text Available The article analyses impact of the ownership structure on corporate management in the engineering industry of Ukraine. In order to detect impact of the structure of corporate ownership on corporate management the article uses general scientific and special methods of study: method of critical analysis and generalisation of theoretical studies, comparison method and statistical method. Analysis of engineering enterprises confirmed availability of impact of the structure of corporate ownership on corporate management. The article also shows that the engineering industry of Ukraine is characterised with the concentrated ownership structure, which has the following features: restriction of rights of minority shareholders with respect to management and control in a joint stock company; availability of corporate conflicts between majority and minority shareholders; availability of intense control of owners over management, which influences efficiency of making managerial decisions; hired managers and enterprise employees have no possibility to acquire stock of a joint stock company including in the form of bonuses and incentives; the controlling owner is interested in efficient activity of the enterprise and tries to create necessary conditions for this. The conducted studies give a possibility to establish that a share of stock that belongs to a hired executive body is smaller in those joint stock companies in which concentration of ownership is higher. The article also shows that the higher ownership concentration the higher is the probability that the owner would be a part of controlling bodies.

  8. Ice Crystal Icing Engine Testing in the NASA Glenn Research Center's Propulsion Systems Laboratory (PSL): Altitude Investigation

    Science.gov (United States)

    Oliver, Michael J.

    2015-01-01

    The National Aeronautics and Space Administration conducted a full scale ice crystal icing turbofan engine test in the NASA Glenn Research Centers Propulsion Systems Laboratory (PSL) Facility in February 2013. Honeywell Engines supplied the test article, an obsolete, unmodified Lycoming ALF502-R5 turbofan engine serial number LF01 that experienced an un-commanded loss of thrust event while operating at certain high altitude ice crystal icing conditions. These known conditions were duplicated in the PSL for this testing.

  9. Engine structure modifications effect on the flow behavior, combustion, and performance characteristics of DI diesel engine

    International Nuclear Information System (INIS)

    Taghavifar, Hadi; Khalilarya, Shahram; Jafarmadar, Samad

    2014-01-01

    Highlights: • Engine geometrical configuration was modified based on bowl radius and displacement. • The best engine performance indices associated with D3 and R1 structures. • Increasing the bowl radius and outward bowl displacement increases ignition delay. • The best configuration for uniform air/fuel mixture, TKE, and temperature is found. - Abstract: The simulation was carried out based on 1.8 L Ford diesel engine and the geometrical modification in structure of piston were considered in terms of bowl movement and the bowl size in four equal increments. Two major conflicting parameters in combustion and engine efficiency were taken into account and visualized in contour plots as the bowl geometry was varied: (1) the air/fuel mixing process demonstrated by Homogeneity Factor and equivalence ratio, (2) combustion initiation and work delivery by heat release rate, pressure curves, and indicated thermal efficiency. A new version of Coherent Flame Model’s sub-model (ECFM-3Z) was adopted during the calculations to shed light into the combustion chemistry and reaction rate in detail. It was found that the bowl displacement toward the cylinder wall, increases the mixture uniformity (higher HF) thus higher pressure and heat release rate peak were obtained with the penalty of combustion delay which substantially reduces the effective in-cylinder pressure. Furthermore, it was demonstrated that smaller bowl size induces better squish and vortex formation in the chamber, although lesser spray penetration and flame quenching owing to the spray-wall impingement reduces ignition delay

  10. Structured electron beams from nano-engineered cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Lueangaramwong, A. [NICADD, DeKalb; Mihalcea, D. [NICADD, DeKalb; Andonian, G. [RadiaBeam Tech.; Piot, P. [Fermilab

    2017-03-07

    The ability to engineer cathodes at the nano-scale have open new possibilities such as enhancing quantum eciency via surface-plasmon excitation, forming ultra-low-emittance beams, or producing structured electron beams. In this paper we present numerical investigations of the beam dynamics associated to this class of cathode in the weak- and strong-field regimes.We finally discuss the possible applications of some of the achievable cathode patterns when coupled with other phase space manipulations.

  11. Self-Regulation and Rubrics Assessment in Structural Engineering Subjects

    Directory of Open Access Journals (Sweden)

    María Consuelo Sáiz Manzanares

    2015-01-01

    Full Text Available Present-day university systems need to educate graduates who are confident and highly independent, attributes that are especially relevant to engineering. We need to develop active methods that can analyze the prior knowledge of students and that impart teaching based on self-regulation and self-assessment by the student. In this study, we work with a sample of 116 students of architecture following a Structural Engineering subject module (61 in the experimental group and 55 in the control group. The objectives of the investigation are (1 to test whether significant differences exist in the knowledge of students after a training program in self-regulation and (2 to test whether the use of rubrics will improve the perceptions of students with regard to their own knowledge. We found that students trained in self-regulation methodologies improved their procedural knowledge in the field of structural engineering. Likewise, student self-perceptions of their own knowledge increased in relation to the design and expert assessment of structural elements and the graphic representation of constructive elements.

  12. Rate-Based Model Predictive Control of Turbofan Engine Clearance

    Science.gov (United States)

    DeCastro, Jonathan A.

    2006-01-01

    An innovative model predictive control strategy is developed for control of nonlinear aircraft propulsion systems and sub-systems. At the heart of the controller is a rate-based linear parameter-varying model that propagates the state derivatives across the prediction horizon, extending prediction fidelity to transient regimes where conventional models begin to lose validity. The new control law is applied to a demanding active clearance control application, where the objectives are to tightly regulate blade tip clearances and also anticipate and avoid detrimental blade-shroud rub occurrences by optimally maintaining a predefined minimum clearance. Simulation results verify that the rate-based controller is capable of satisfying the objectives during realistic flight scenarios where both a conventional Jacobian-based model predictive control law and an unconstrained linear-quadratic optimal controller are incapable of doing so. The controller is evaluated using a variety of different actuators, illustrating the efficacy and versatility of the control approach. It is concluded that the new strategy has promise for this and other nonlinear aerospace applications that place high importance on the attainment of control objectives during transient regimes.

  13. 77 FR 16139 - Airworthiness Directives; Pratt & Whitney (PW) Turbofan Engines

    Science.gov (United States)

    2012-03-20

    ... edge, installed. This AD was prompted by reports from PW that fan blade leading edge erosion can result... commenters stated that Repair-18 is a bench repair that removes erosion damage and restores the leading edge... prompted by reports from PW that fan blade leading edge erosion can result in a fan thrust deterioration...

  14. 78 FR 49111 - Airworthiness Directives; Pratt & Whitney Division Turbofan Engines

    Science.gov (United States)

    2013-08-13

    ... performed using prior versions of Alert Service Bulletin (ASB) No. PW4G-112-A72- 330. The reason for this... prior version of the ASB should remain valid. We agree. We added a Credit for Previous Actions paragraph... Inspection Interval UAL requested that we include a reduced inspection interval based on the results of the...

  15. 77 FR 57007 - Airworthiness Directives; Pratt & Whitney Division Turbofan Engines

    Science.gov (United States)

    2012-09-17

    ...) for cracks in the blade loading and locking slots of the high-pressure compressor (HPC) drum rotor... Atlas Air, requested that we reference the latest revisions of two SBs which were revised since the... in the proposed AD supersedure. We did not change the AD. Request To Revise Paragraph (f)(2) Atlas...

  16. 77 FR 4650 - Airworthiness Directives; General Electric Company Turbofan Engines

    Science.gov (United States)

    2012-01-31

    ...: (800) 647-5527) is Document Management Facility, U.S. Department of Transportation, Docket Operations... AD. The following presents the comments received on the proposal and the FAA's response to each... paragraphs (k)(2) through (k)(3) of this AD.'' Request To Add a Requirement for Raw Exhaust Gas Temperature...

  17. Harnessing natural product assembly lines: structure, promiscuity, and engineering

    Science.gov (United States)

    Ladner, Christopher C; Williams, Gavin J

    2015-01-01

    Many therapeutically relevant natural products are biosynthesized by the action of giant mega-enzyme assembly lines. By leveraging the specificity, promiscuity, and modularity of assembly lines, a variety of strategies have been developed that enable the biosynthesis of modified natural products. This review briefly summarizes recent structural advances related to natural product assembly lines, discusses chemical approaches to probing assembly line structures in the absence of traditional biophysical data, and surveys efforts that harness the inherent or engineered promiscuity of assembly lines for the synthesis of non-natural polyketides and nonribosomal peptide analogues. PMID:26527577

  18. Harnessing natural product assembly lines: structure, promiscuity, and engineering.

    Science.gov (United States)

    Ladner, Christopher C; Williams, Gavin J

    2016-03-01

    Many therapeutically relevant natural products are biosynthesized by the action of giant mega-enzyme assembly lines. By leveraging the specificity, promiscuity, and modularity of assembly lines, a variety of strategies has been developed that enables the biosynthesis of modified natural products. This review briefly summarizes recent structural advances related to natural product assembly lines, discusses chemical approaches to probing assembly line structures in the absence of traditional biophysical data, and surveys efforts that harness the inherent or engineered promiscuity of assembly lines for the synthesis of non-natural polyketides and non-ribosomal peptide analogues.

  19. FROM GEOMETRY TO DIAGNOSIS: EXPERIENCES OF GEOMATICS IN STRUCTURAL ENGINEERING

    Directory of Open Access Journals (Sweden)

    B. Riveiro

    2012-07-01

    Full Text Available Terrestrial photogrammetry and laser scanning are technologies that have been successfully used for metric surveying and 3D modelling in many different fields (archaeological and architectural documentation, industrial retrofitting, mining, structural monitoring, road surveying, etc.. In the case of structural applications, these techniques have been successfully applied to 3D modelling and sometimes monitoring; but they have not been sufficiently implemented to date, as routine tools in infrastructure management systems, in terms of automation of data processing and integration in the condition assessment procedures. In this context, this paper presents a series of experiences in the usage of terrestrial photogrammetry and laser scanning in the context of dimensional and structural evaluation of structures. These experiences are particularly focused on historical masonry structures, but modern prestressed concrete bridges are also investigated. The development of methodological procedures for data collection, and data integration in some cases, is tackled for each particular structure (with access limitations, geometrical configuration, range of measurement, etc.. The accurate geometrical information provided by both terrestrial techniques motivates the implementation of such results in the complex, and sometimes slightly approximated, geometric scene that is frequently used in structural analysis. In this sense, quantitative evaluating of the influence of real and accurate geometry in structural analysis results must be carried out. As main result in this paper, a series of experiences based on the usage of photogrammetric and laser scanning to structural engineering are presented.

  20. From Geometry to Diagnosis: Experiences of Geomatics in Structural Engineering

    Science.gov (United States)

    Riveiro, B.; Arias, P.; Armesto, J.; Caamaño, J. C.; Solla, M.

    2012-07-01

    Terrestrial photogrammetry and laser scanning are technologies that have been successfully used for metric surveying and 3D modelling in many different fields (archaeological and architectural documentation, industrial retrofitting, mining, structural monitoring, road surveying, etc.). In the case of structural applications, these techniques have been successfully applied to 3D modelling and sometimes monitoring; but they have not been sufficiently implemented to date, as routine tools in infrastructure management systems, in terms of automation of data processing and integration in the condition assessment procedures. In this context, this paper presents a series of experiences in the usage of terrestrial photogrammetry and laser scanning in the context of dimensional and structural evaluation of structures. These experiences are particularly focused on historical masonry structures, but modern prestressed concrete bridges are also investigated. The development of methodological procedures for data collection, and data integration in some cases, is tackled for each particular structure (with access limitations, geometrical configuration, range of measurement, etc.). The accurate geometrical information provided by both terrestrial techniques motivates the implementation of such results in the complex, and sometimes slightly approximated, geometric scene that is frequently used in structural analysis. In this sense, quantitative evaluating of the influence of real and accurate geometry in structural analysis results must be carried out. As main result in this paper, a series of experiences based on the usage of photogrammetric and laser scanning to structural engineering are presented.

  1. 75 FR 64681 - Airworthiness Directives; General Electric Company (GE) CF6-45 Series and CF6-50 Series Turbofan...

    Science.gov (United States)

    2010-10-20

    ...The FAA proposes to adopt a new airworthiness directive (AD) for GE CF6-45 and CF6-50 series turbofan engines. This proposed AD would require performing a fluorescent penetrant inspection (FPI) of the stage 3 low-pressure turbine (LPT) rotor at every shop visit at which the LPT module is separated from the engine. This proposed AD results from seven reports of uncontained failures of LPT stage 3 disks and eight reports of cracked LPT stage 3 disks found during shop visit inspections. We are proposing this AD to prevent LPT rotor separation, which could result in an uncontained engine failure and damage to the airplane.

  2. Vibration-based localisation of structural deterioration in frame-like civil engineering structures

    DEFF Research Database (Denmark)

    Ulriksen, Martin Dalgaard; Damkilde, Lars

    2016-01-01

    With the existing trend of minimising material use in typical frame-like civil engineering structures, such as buildings, bridges, and offshore platforms, these structures will typically be subjected to substantial wind induced vibrations. Besides being a source of disturbance for the occupants...

  3. Organizational structure of power engineering of Kazakhstan. Chapter 4

    International Nuclear Information System (INIS)

    1998-01-01

    Pathways of integration in Kazakhstan power engineering are considered and economic structure formation in the branch is revealed as well. In 1994 privatization plan for power engineering branch was accepted. All state enterprises were reorganize in to joint-stock companies. At that there is single state monopoly company - National Power System (NPS) Kazakhstanehnergo. NPS makes a wholesale market of electric energy at the expense of it generation at base power plants, additional purchase abroad, following transport in all regions and its selling to territorial power companies as well as separate buyers. Last time wide application of commercial principles in state sector is observed. For formation of wholesale and retail markets was organized Kazakhstan EnergoPool

  4. Structural Evaluation of Exo-Skeletal Engine Fan Blades

    Science.gov (United States)

    Kuguoglu, Latife; Abumeri, Galib; Chamis, Christos C.

    2003-01-01

    The available computational simulation capability is used to demonstrate the structural viability of composite fan blades of innovative Exo-Skeletal Engine (ESE) developed at NASA Glenn Research Center for a subsonic mission. Full structural analysis and progressive damage evaluation of ESE composite fan blade is conducted through the NASA in-house computational simulation software system EST/BEST. The results of structural assessment indicate that longitudinal stresses acting on the blade are in compression. At a design speed of 2000 rpm, pressure and suction surface outer most ply stresses in longitudinal, transverse and shear direction are much lower than the corresponding composite ply strengths. Damage is initiated at 4870 rpm and blade fracture takes place at rotor speed of 7735 rpm. Damage volume is 51 percent. The progressive damage, buckling, stress and strength results indicate that the design at hand is very sound because of the factor of safety, damage tolerance, and buckling load of 6811 rpm.

  5. Analysis of eddy current loadings in fusion engineering structures

    International Nuclear Information System (INIS)

    Bialek, J.M.; Weissenburger, D.W.

    1983-01-01

    We have investigated both analytically and numerically the eddy current loadings found in fusion engineering structures. The largest loadings of this type arise from plasma disruptions. These loads (in the TFTR device) appear on the time scale of a plasma disruption (approx.=10 -3 s) and may easily reach 3x10 5 N/m or greater in magnitude. While these loads cause no problems in the primary structure of a fusion engineering device, they may easily become the design load for protective systems and diagnostics. We first present a simple analytical analysis of the eddy current loading phenomena. Then, we describe the calculation techniques that have been developed to solve numerically for the general behavior of a transient electromagnetic event. These techniques have been used in developing the computer program SPARK, which is now used at the Princeton Plasma Physics Laboratory to solve the general eddy current loading problem. Lastly, some results from SPARK are presented and the manner in which the results from SPARK are translated into a form compatible with the local structural finite element code, NASTRAN, are described. (orig.)

  6. Ballistic and Cyclic Rig Testing of Braided Composite Fan Case Structures

    Science.gov (United States)

    Watson, William R.; Roberts, Gary D.; Pereira, J. Michael; Braley, Michael S.

    2015-01-01

    FAA fan blade-out certification testing on turbofan engines occurs very late in an engine's development program and is very costly. It is of utmost importance to approach the FAA Certification engine test with a high degree of confidence that the containment structure will not only contain the high-energy debris, but that it will also withstand the cyclic loads that occur with engine spooldown and continued rotation as the non-running engine maintains a low rotor RPM due to forced airflow as the engine-out aircraft returns to an airport. Accurate rig testing is needed for predicting and understanding material behavior of the fan case structure during all phases of this fan blade-out event.

  7. Monitoring of civil engineering structures using Digital Image Correlation technique

    Directory of Open Access Journals (Sweden)

    Świercz A.

    2010-06-01

    Full Text Available The Digital Image Correlation (DIC technique enables full field, noncontact measurements of displacements and strains of a wide variety of objects. An adaptation of the DIC technique for monitoring of civil-engineering structures is presented in the paper. A general concept of the complex, automatic monitoring system, in which the DIC sensor plays an important role is described. Some new software features, which aim to facilitate outdoor measurements and speed up the correlation analysis, is also introduced. As an example of application, measurements of a railway bridge in Nieporet (Poland are presented. The experimental results are compared with displacements of a FEM model of the bridge.

  8. Grain boundary engineering for structure materials of nuclear reactors

    Science.gov (United States)

    Tan, L.; Allen, T. R.; Busby, J. T.

    2013-10-01

    Grain boundary engineering (GBE), primarily implemented by thermomechanical processing, is an effective and economical method of enhancing the properties of polycrystalline materials. Among the factors affecting grain boundary character distribution, literature data showed definitive effect of grain size and texture. GBE is more effective for austenitic stainless steels and Ni-base alloys compared to other structural materials of nuclear reactors, such as refractory metals, ferritic and ferritic-martensitic steels, and Zr alloys. GBE has shown beneficial effects on improving the strength, creep strength, and resistance to stress corrosion cracking and oxidation of austenitic stainless steels and Ni-base alloys.

  9. Grain boundary engineering for structure materials of nuclear reactors

    International Nuclear Information System (INIS)

    Tan, L.; Allen, T.R.; Busby, J.T.

    2013-01-01

    Grain boundary engineering (GBE), primarily implemented by thermomechanical processing, is an effective and economical method of enhancing the properties of polycrystalline materials. Among the factors affecting grain boundary character distribution, literature data showed definitive effect of grain size and texture. GBE is more effective for austenitic stainless steels and Ni-base alloys compared to other structural materials of nuclear reactors, such as refractory metals, ferritic and ferritic–martensitic steels, and Zr alloys. GBE has shown beneficial effects on improving the strength, creep strength, and resistance to stress corrosion cracking and oxidation of austenitic stainless steels and Ni-base alloys

  10. Smart Sensing Technologies for Structural Health Monitoring of Civil Engineering Structures

    Directory of Open Access Journals (Sweden)

    M. Sun

    2010-01-01

    Full Text Available Structural Health Monitoring (SHM aims to develop automated systems for the continuous monitoring, inspection, and damage detection of structures with minimum labour involvement. The first step to set up a SHM system is to incorporate a level of structural sensing capability that is reliable and possesses long term stability. Smart sensing technologies including the applications of fibre optic sensors, piezoelectric sensors, magnetostrictive sensors and self-diagnosing fibre reinforced composites, possess very important capabilities of monitoring various physical or chemical parameters related to the health and therefore, durable service life of structures. In particular, piezoelectric sensors and magnetorestrictive sensors can serve as both sensors and actuators, which make SHM to be an active monitoring system. Thus, smart sensing technologies are now currently available, and can be utilized to the SHM of civil engineering structures. In this paper, the application of smart materials/sensors for the SHM of civil engineering structures is critically reviewed. The major focus is on the evaluations of laboratory and field studies of smart materials/sensors in civil engineering structures.

  11. Seismic qualification of civil engineering structures - Temelin NPP

    International Nuclear Information System (INIS)

    Schererova, K.; Holub, I.; Stepan, J.; Maly, J.

    2004-01-01

    Basic information is presented about the input data and methodology used for evaluation of Temelin NPP civil structures. The existing conditions as listed in POSAR report for the two reactor units are considered. The original design of the power plant assumed a lower level of locality seismic hazard, as followed from seismological surveys that where then available. Later the seismic assessment was updated while fully respecting IAEA recommendations and using a minimum value of acceleration in the horizontal direction PGAHOR = 0.1 g at free field level for SL-2. In relation to the new seismic project, new qualification of the structures, components and systems classed as seismic resistance category 1 was carried out. Since the Czech Republic has no specific technical standards for seismic resistance evaluation of nuclear power plants, a detailed methodology was elaborated, comprising principles of seismic resistance evaluation based on IAEA guides and on common practice in countries with advanced nuclear power engineering. (P.A.)

  12. Band structure engineered layered metals for low-loss plasmonics

    Science.gov (United States)

    Gjerding, Morten N.; Pandey, Mohnish; Thygesen, Kristian S.

    2017-04-01

    Plasmonics currently faces the problem of seemingly inevitable optical losses occurring in the metallic components that challenges the implementation of essentially any application. In this work, we show that Ohmic losses are reduced in certain layered metals, such as the transition metal dichalcogenide TaS2, due to an extraordinarily small density of states for scattering in the near-IR originating from their special electronic band structure. On the basis of this observation, we propose a new class of band structure engineered van der Waals layered metals composed of hexagonal transition metal chalcogenide-halide layers with greatly suppressed intrinsic losses. Using first-principles calculations, we show that the suppression of optical losses lead to improved performance for thin-film waveguiding and transformation optics.

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

    Directory of Open Access Journals (Sweden)

    B. Novotný

    2000-01-01

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

  14. A unified approach to failure assessment of engineering structures

    International Nuclear Information System (INIS)

    Harrison, R.P.

    1977-01-01

    A codified procedure for the failure assessment of engineering structures is presented which has as its basis the two criteria approach of Dowling and Townley (Int. J. Press. Vessels and Piping; 3:77 (1975)) and the Bilby, Cottrell and Swinden (Proc. R. Soc.; A272:304 (1963)) and Dugdale (J. Mech. Phys. Sol.; 8:100 (1960)) model of yielding ahead of a crack tip. The procedure consists of independently assessing the risk of failure (a) under linear elastic conditions only and (b) under plastic collapse conditions only. These two limiting criteria are then plotted as a co-ordinate point on a Failure Assessment Diagram. From this a measure of the degree of safety of the structure can be obtained. As examples, several of the HSST vessel tests are used to indicate the simplicity and versatility of the procedure. It is shown how maximum allowable pressures or defect sizes can be obtained and how safety factors can be readily incorporated on any of the parameters used in the assessment. It is also demonstrated how helpful the procedure is in designing not only working structures, but also structures that are to be used for testing. (author)

  15. Dimensionality Reduction for Damage Detection in Engineering Structures

    Science.gov (United States)

    Prada, Miguel A.; Domínguez, Manuel; Barrientos, Pablo; García, Sergio

    2012-10-01

    The detection of damages in engineering structures by means of the changes in their vibration response is called structural health monitoring (SHM). It is a promising field but presents fundamental challenges. Accurate theoretical models of the structure are generally unfeasible, so data-based approaches are required. Indeed, only data from the undamaged condition are usually available, so the approach needs to be framed as novelty detection. Data are acquired from a network of sensors to measure local changes in the operating condition of the structures. In order to distinguish changes produced by damages from those caused by the environmental conditions, several physically meaningful features have been proposed, most of them in the frequency domain. Nevertheless, multiple measurement locations and the absence of a principled criterion to select among the potentially damage-sensitive features contribute to increase data dimensionality. Since high dimensionality affects the effectiveness of damage detection, we evaluate the effect of a dimensionality reduction approach in the diagnostic accuracy of damage detection.

  16. The Effect of Bypass Nozzle Exit Area on Fan Aerodynamic Performance and Noise in a Model Turbofan Simulator

    Science.gov (United States)

    Hughes, Christopher E.; Podboy, Gary, G.; Woodward, Richard P.; Jeracki, Robert, J.

    2013-01-01

    The design of effective new technologies to reduce aircraft propulsion noise is dependent on identifying and understanding the noise sources and noise generation mechanisms in the modern turbofan engine, as well as determining their contribution to the overall aircraft noise signature. Therefore, a comprehensive aeroacoustic wind tunnel test program was conducted called the Fan Broadband Source Diagnostic Test as part of the NASA Quiet Aircraft Technology program. The test was performed in the anechoic NASA Glenn 9- by 15-Foot Low Speed Wind Tunnel using a 1/5 scale model turbofan simulator which represented a current generation, medium pressure ratio, high bypass turbofan aircraft engine. The investigation focused on simulating in model scale only the bypass section of the turbofan engine. The test objectives were to: identify the noise sources within the model and determine their noise level; investigate several component design technologies by determining their impact on the aerodynamic and acoustic performance of the fan stage; and conduct detailed flow diagnostics within the fan flow field to characterize the physics of the noise generation mechanisms in a turbofan model. This report discusses results obtained for one aspect of the Source Diagnostic Test that investigated the effect of the bypass or fan nozzle exit area on the bypass stage aerodynamic performance, specifically the fan and outlet guide vanes or stators, as well as the farfield acoustic noise level. The aerodynamic performance, farfield acoustics, and Laser Doppler Velocimeter flow diagnostic results are presented for the fan and four different fixed-area bypass nozzle configurations. The nozzles simulated fixed engine operating lines and encompassed the fan stage operating envelope from near stall to cruise. One nozzle was selected as a baseline reference, representing the nozzle area which would achieve the design point operating conditions and fan stage performance. The total area change from

  17. Structure-property relations in engineered semiconductor nanomaterials (Conference Presentation)

    Science.gov (United States)

    Hollingsworth, Jennifer A.; Htoon, Han

    2016-09-01

    Particle-size or `quantum-confinement' effects have been used for decades to tune semiconductor opto-electronic properties. More recently, particle size control as the primary means for properties control has been succeeded by nanoscale hetero-structuring. In this case, the nanosized particle is modified to include internal, nanoscale interfaces, generally defined by compositional variations that induce additional changes to semiconductor properties. These changes can entail enhancements to the size-induced properties as well as unexpected or `emergent' behaviors. Common structural motifs include enveloping a spherical semiconductor nanocrystal, i.e., a quantum dot, within a shell of a different composition. In this talk, I will discuss how solution-phase synthesis can be used to create these structures with precisely `engineered' complexity. Most notably, I will review our experiences with so-called `giant' quantum dots that, due to their internal nanoscale structure, exhibit a range of novel behaviors, including being non-blinking and non-photobleaching (Chen et al. J. Am. Chem. Soc. 2008, 130, 5026; Ghosh et al. J. Am. Chem. Soc. 2012, 134, 9634; Dennis et al. Nano Lett. 2012 12, 5545; Acharya et al. J. Am. Chem. Soc. 2015, 137, 3755), and remarkably efficient emitters of `multi-excitons' due to extreme suppression of Auger recombination (Mangum et al. Nanoscale 2014, 6, 3712; Gao et al. Adv. Optical Mater. 2015, 3, 39). I will discuss recent work extending non-blinking behavior to the blue/green and "dual-color" emission, and show how correlated optical/structural characterization can reveal new information regarding structure-property relations to guide new nanomaterials development (Orfield et al. ACS Nano, Article ASAP).

  18. Engineering excellence at Rolls-Royce; a taste of English culture

    NARCIS (Netherlands)

    Schnelders, J.

    2013-01-01

    Rolls-Royce is one of the most well-known brands in the world and synonymous with the highest engineering quality. Amongst Aerospace Engineers, Rolls-Royce is directly associated with the Trent turbofan aircraft engines. The engines power the world’s newest passenger aircraft, including the Boeing

  19. Estimating Modal Parameters of Civil Engineering Structures subject to Ambient and Harmonic Excitation

    DEFF Research Database (Denmark)

    Andersen, Palle; Brincker, Rune; Ventura, Carlos

    In this paper addresses the problems of separating structural modes and harmonics arising from sinusoidal excitation. Though the problem is mostly know in mechanical engineering applications such as rotating machinery, some civil engineering applications experiences the same challenges. A robust...... and fast harmonic detection procedure is presented and illustrated on a civil engineering case....

  20. Identification of Civil Engineering Structures using Multivariate ARMAV and RARMAV Models

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Andersen, P.; Brincker, Rune

    This paper presents how to make system identification of civil engineering structures using multivariate auto-regressive moving-average vector (ARMAV) models. Further, the ARMAV technique is extended to a recursive technique (RARMAV). The ARMAV model is used to identify measured stationary data....... The results show the usefulness of the approaches for identification of civil engineering structures excited by natural excitation...

  1. Pollution reduction technology program for small jet aircraft engines: Class T1

    Science.gov (United States)

    Bruce, T. W.; Davis, F. G.; Mongia, H. C.

    1977-01-01

    Small jet aircraft engines (EPA class T1, turbojet and turbofan engines of less than 35.6 kN thrust) were evaluated with the objective of attaining emissions reduction consistent with performance constraints. Configurations employing the technological advances were screened and developed through full scale rig testing. The most promising approaches in full-scale engine testing were evaluated.

  2. Band structure engineering for ultracold quantum gases in optical lattices

    International Nuclear Information System (INIS)

    Weinberg, Malte

    2014-01-01

    The energy band structure fundamentally influences the physical properties of a periodic system. It may give rise to highly exotic phenomena in yet uncharted physical regimes. Ultracold quantum gases in optical lattices provide an ideal playground for the investigation of a large variety of such intriguing effects. Experiments presented here address several issues that require the systematic manipulation of energy band structures in optical lattices with diverse geometries. These artificial crystals of light, generated by interfering laser beams, allow for an unprecedented degree of control over a wide range of parameters. A major part of this thesis employs time-periodic driving to engineer tunneling matrix elements and, thus, the dispersion relation for bosonic quantum gases in optical lattices. Resonances emerging in the excitation spectrum due to the particularly strong forcing can be attributed to multi-photon transitions that are investigated systematically. By changing the sign of the tunneling, antiferromagnetic spin-spin interactions can be emulated. In a triangular lattice this leads to geometrical frustration with a doubly degenerate ground state as the simultaneous minimization of competing interactions is inhibited. Moreover, complex-valued tunneling matrix elements can be generated with a suitable breaking of time-reversal symmetry in the driving scheme. The associated Peierls phases mimic the presence of an electromagnetic vector gauge potential acting on charged particles. First proof-of-principle experiments reveal an excellent agreement with theoretical calculations. In the weakly interacting superfluid regime, these artificial gauge fields give rise to an Ising-XY model with tunable staggered magnetic fluxes and a complex interplay between discrete and continuous symmetries. A thermal phase transition from an ordered ferromagnetic- to an unordered paramagnetic state could be observed. In the opposite hard-core boson limit of strong interactions

  3. Acoustic Performance of an Advanced Model Turbofan in Three Aeroacoustic Test Facilities

    Science.gov (United States)

    Woodward, Richard P.; Hughes, Christopher E.

    2012-01-01

    A model advanced turbofan was acoustically tested in the NASA Glenn 9- by 15-Foot-Low-Speed Wind Tunnel (LSWT), and in two other aeroacoustic facilities. The Universal Propulsion Simulator (UPS) fan was designed and manufactured by the General Electric Aircraft Engines (GEAE) Company, and featured active core, as well as bypass, flow paths. The reference test configurations were with the metal, M4, rotor with hardwall and treated bypass flow ducts. The UPS fan was tested within an airflow at a Mach number of 0.20 (limited flow data were also acquired at a Mach number of 0.25) which is representative of aircraft takeoff and approach conditions. Comparisons were made between data acquired within the airflow (9x15 LSWT and German-Dutch Wind Tunnel (DNW)) and outside of a free jet (Boeing Low Speed Aero acoustic Facility (LSAF) and DNW). Sideline data were acquired on an 89-in. (nominal 4 fan diameters) sideline using the same microphone assembly and holder in the 9x15 LSWT and DNW facilities. These data showed good agreement for similar UPS operating conditions and configurations. Distortion of fan spectra tonal content through a free jet shear layer was documented, suggesting that in-flow acoustic measurements are required for comprehensive fan noise diagnostics. However, there was good agreement for overall sound power level (PWL) fan noise measurements made both within and outside of the test facility airflow.

  4. Variable Geometry Aircraft Pylon Structure and Related Operation Techniques

    Science.gov (United States)

    Shah, Parthiv N. (Inventor)

    2014-01-01

    An aircraft control structure can be utilized for purposes of drag management, noise control, or aircraft flight maneuvering. The control structure includes a high pressure engine nozzle, such as a bypass nozzle or a core nozzle of a turbofan engine. The nozzle exhausts a high pressure fluid stream, which can be swirled using a deployable swirl vane architecture. The control structure also includes a variable geometry pylon configured to be coupled between the nozzle and the aircraft. The variable geometry pylon has a moveable pylon section that can be deployed into a deflected state to maintain or alter a swirling fluid stream (when the swirl vane architecture is deployed) for drag management purposes, or to assist in the performance of aircraft flight maneuvers.

  5. Decommissioning engineering within the framework of the French nuclear structure

    International Nuclear Information System (INIS)

    Rodrigues, S.

    1982-01-01

    The engineering studies leading to the preparation of the technical construction docket are performed by expertised and specialized teams. It is advisable that the operating staff of the concerned facility might closely participate in the engineering studies and assist the specialized engineering team, as it is well acquainted with the facility to be dismantled. The technical file specifies: (1) the techniques to be implemented ensuring their mutual compatibility; (2) the strict organization of operations from the standpoint of feasibility and schedule; (3) the allocation of work segments of such operations; (4) the works supply contracts and limits of liability of the contractors involved; and (5) the required equipment procurements (e.g. robots). The engineering studies are further used for the construction studies to be completed by the selected contractors. 1 reference, 2 figures, 1 table

  6. M.Sc. in Civil and Structural Engineering

    DEFF Research Database (Denmark)

    Clausen, Johan Christian

    The following pages contain a list of project ideas proposed by the scientific staff at the Department of Civil Engineering, Aalborg University, and a number of companies. Most of the project ideas in this catalogue may form the basis for long and short master projects as well as regular 3rd...... page. Furthermore, other ideas for projects may be discussed with a potential supervisor. Many private engineering companies have a homepage on which they state that they would like to collaborate with students on a master project....

  7. Cylinder head fastening structure for internal combustion engines

    Energy Technology Data Exchange (ETDEWEB)

    Futakuchi, Y.; Oshiro, N.

    1988-01-26

    In a construction for an overhead cam internal combustion engine comprising a cylinder head adapted to be affixed to another component of the engine by at least one fastener having a tool receiving portion for tightening thereof and having a bearing cap affixed to the cylinder head and rotatably journaling the overhead camshaft, the improvement is described comprising the bearing cap having a portion overlying the fastener tool receiving portion, and means defining an access opening passing through the bearing cap and adapted to pass a tool for tightening of the fastener without removal of the bearing cap.

  8. M.Sc. in Civil and Structural Engineering

    DEFF Research Database (Denmark)

    The following pages contain a list of project ideas proposed by the scientific staff at the Department of Civil Engineering, Aalborg University, and a number of companies. Most of the project ideas in this catalogue may form the basis for long and short master projects as well as regular 3rd...

  9. Somatic structural rearrangements in genetically engineered mouse mammary tumors

    NARCIS (Netherlands)

    Varela, I.; Klijn, C.N.; Stephens, P.J.; Mudie, L.J.; Stebbings, L.; Galappaththige, D.; Van der Gulden, H.; Schut, E.; Klarenbeek, S.; Campbell, P.J.; Wessels, L.F.A.; Stratton, M.R.; Jonkers, J.; Futreal, P.A.; Adams, D.J.

    2010-01-01

    Background: Here we present the first paired-end sequencing of tumors from genetically engineered mouse models of cancer to determine how faithfully these models recapitulate the landscape of somatic rearrangements found in human tumors. These were models of Trp53-mutated breast cancer, Brca1- and

  10. Elements of Motivational Structure for Studying Mechanical Engineering

    Science.gov (United States)

    Dubreta, Nikša; Miloš, Damir

    2017-01-01

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

  11. Pre-Service Science Teachers' Cognitive Structures Regarding Science, Technology, Engineering, Mathematics (STEM) and Science Education

    Science.gov (United States)

    Hacioglu, Yasemin; Yamak, Havva; Kavak, Nusret

    2016-01-01

    The aim of this study is to reveal pre-service science teachers' cognitive structures regarding Science, Technology, Engineering, Mathematics (STEM) and science education. The study group of the study consisted of 192 pre-service science teachers. A Free Word Association Test (WAT) consisting of science, technology, engineering, mathematics and…

  12. Engineering data management through different breakdown structures in a large-scale project

    CERN Document Server

    Hameri, A P

    2002-01-01

    This document discusses the benefits stemming from managing different project breakdown structures with an engineering data management system. The structures discussed are project breakdown structure (PBS), assembly breakdown structure (ABS), as-built structure and hardware breakdown. Each structure is presented from the quality management point of view and a practical example of each of the four structures is given to illustrate their differences, and to show what kind of engineering information is to be stored in these structures. The main underlying case is that of CERN and its global, over a decade-long Large Hadron Collider project. The approach used for managing the new particle accelerator project is benchmarked against the way large-scale shipbuilding projects are managed. It is concluded that several structures are needed to manage complex system projects, and that linking information between structures plays a crucial role for the overall success of the project. Information technology and the WWW ar...

  13. Slave finite elements for nonlinear analysis of engine structures, volume 1

    Science.gov (United States)

    Gellin, S.

    1991-01-01

    A 336 degrees of freedom slave finite element processing capability to analyze engine structures under severe thermomechanical loading is presented. Description of the theoretical development and demonstration of that element is presented in this volume.

  14. Nano-Material and Structural Engineering for Thermal Highways

    Science.gov (United States)

    2013-06-14

    engine self-lubrication, fuel cell supply and water removal, and drug delivery or biofluid sample extraction. The heating and cooling process of the...with the relation of SE=-10log(T). In order to obtain the IR reflectance, plasma frequency and real and imaginary parts of permittivity , the Drude...lubrication, fuel cell supply and water removal, and drug delivery or biofluid sample extraction. Another application that has garnered some interest is the

  15. Conceptual study of advanced VTOL transport aircraft engine

    OpenAIRE

    Saito, Yoshio; Endo, Masanori; Matsuda, Yukio; Sugiyama, Nanahisa; Watanabe, Minoru; Sugahara, Noboru; Yamamoto, Kazuomi; 齊藤 喜夫; 遠藤 征紀; 松田 幸雄; 杉山 七契; 渡辺 実; 菅原 昇; 山本 一臣

    1996-01-01

    A new concept for a quiet engine for high subsonic VTOL transport aircraft is studied and presented. The concept engine, which is called the separated core turbofan engine, is effectively applied. It is composed of three core engines, two cruise fan engines and six lift fan engines. The cruise fan engines are optimized for high subsonic cruise, and the lift fan engines produce about 98 kN (10,000 kgf) of thrust and can realize highly quiet operation. In this study, no technical problems have ...

  16. Engineering of spatial solitons in two-period QPM structures

    DEFF Research Database (Denmark)

    Johansen, Steffen Kjær; Carrasco, Silvia; Torner, Lluis

    2002-01-01

    We report on a scheme which might make it practically possible to engineer the effective competing nonlinearities that on average govern the light propagation in quasi-phase-matching (QPM) gratings. Modulation of the QPM period with a second longer period, introduces an extra degree of freedom...... relative lengths of the two periods and we consider the effect on solitons and the bandwidth for their generation. We derive an expression for the bandwidth of multicolor soliton generation in two-period QPM samples and we predict and confirm numerically that the bandwidth is broader in the two-period QPM...

  17. Purdue Plane Structures Analyzer II : a computerized wood engineering system

    Science.gov (United States)

    S. K. Suddarth; R. W. Wolfe

    1984-01-01

    The Purdue Plane Structures Analyzer (PPSA) is a computer program developed specifically for the analysis of wood structures. It uses recognized analysis procedures, in conjunction with recommendations of the 1982 National Design Specification for Wood Construction, to determine stresses and deflections of wood trusses and frames. The program offers several options for...

  18. Modeling the Structure and Complexity of Engineering Routine Design Problems

    NARCIS (Netherlands)

    Jauregui Becker, Juan Manuel; Wits, Wessel Willems; van Houten, Frederikus J.A.M.

    2011-01-01

    This paper proposes a model to structure routine design problems as well as a model of its design complexity. The idea is that having a proper model of the structure of such problems enables understanding its complexity, and likewise, a proper understanding of its complexity enables the development

  19. THE PHILOSOPHY - TOOL CONTINUUM: PROVIDING STRUCTURE TO INDUSTRIAL ENGINEERING CONCEPTS

    Directory of Open Access Journals (Sweden)

    L. Van Dyk

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: Industrial Engineering concepts are often referred to as either a tool, technique, method, approach or philosophy. These terminologies can be positioned on a continuum according to their meaning as defined by the Oxford English dictionary (tools B techniques Bmethods B approaches B philosophies. The philosophy of Total Quality Management is used as example to show how the appropriate naming of Industrial Engineering concepts can enhance the understanding and application thereof. This continuum is used to show that although the philosophies of TQM and Scientific Management may differ, the same pool of tools and techniques are used by both of these philosophies.

    AFRIKAANSE OPSOMMING: Bedryfsingenieurs verwys dikwels na filosofiee, benaderings, metodes, tegnieke en gereedskap. Hierdie terminologiee kan kan op 'n kontinuum geposisioneer word na aanleiding van hulle woordeboekbetekenis (gereedskap f-t tegniek f-t metode f-t benadering f-t filosofie. Die filosofie .van Totale Kwaliteitsbeheer (TQM word as voorbeeld gebruik om te wys dat die gepaste benaming van Bedryfsingenieurskonsepte die begrip en toepassing daarvan verhoog . Hierdie kontinuum word gebruik om te wys dat, alhoewel die filosofie van TQM en Wetenskaplike Bestuur ("Scientific Management" verskil, dieselfde versameling vail gereedskap en tegnieke deur beide gebruik word.

  20. Quiet Clean Short-haul Experimental Engine (QCSEE). Core engine noise measurements

    Science.gov (United States)

    Sowers, H. D.; Coward, W. E.

    1977-01-01

    Noise measurements were taken on a turbofan engine which uses the same core, with minor modifications, employed on the quiet clean short-haul experimental engine (QCSEE) propulsion systems. Both nearfield and farfield noise measurements were taken in order to determine the core internally generated noise levels. The resulting noise measurements were compared to predicted combustor and turbine noise levels, to verify or improve the predicted QCSEE combustor and turbine noise levels.

  1. Detailed Post-Soft Impact Progressive Damage Assessment for Hybrid Structure Jet Engines

    Science.gov (United States)

    Siddens, Aaron; Bayandor, Javid; Celestina, Mark L.

    2014-01-01

    Currently, certification of engine designs for resistance to bird strike is reliant on physical tests. Predictive modeling of engine structural damage has mostly been limited to evaluation of individual forward section components, such as fan blades within a fixed frame of reference, to direct impact with a bird. Such models must be extended to include interactions among engine components under operating conditions to evaluate the full extent of engine damage. This paper presents the results of a study aim to develop a methodology for evaluating bird strike damage in advanced propulsion systems incorporating hybrid composite/metal structures. The initial degradation and failure of individual fan blades struck by a bird were investigated. Subsequent damage to other fan blades and engine components due to resultant violent fan assembly vibrations and fragmentation was further evaluated. Various modeling parameters for the bird and engine components were investigated to determine guidelines for accurately capturing initial damage and progressive failure of engine components. Then, a novel hybrid structure modeling approach was investigated and incorporated into the crashworthiness methodology. Such a tool is invaluable to the process of design, development, and certification of future advanced propulsion systems.

  2. Between a rock and a hard place: Environmental and engineering considerations when designing coastal defence structures

    NARCIS (Netherlands)

    Firth, L.B.; Thompson, R.C.; Bohn, K.; Abbiati, M.; Airoldi, L.; Bouma, T.J.; Bozzeda, F.; Ceccherelli, V.U.; Colangelo, M.A.; Evans, A.; Ferrario, F.; Hanley, M.E.; Hinz, H.; Hoggart, S.P.G.; Jackson, J.E.; Moore, P.; Morgan, E.H.; Perkol-Finkel, S.; Skov, M.W.; Strain, E.M.; van Belzen, J.; Hawkins, S.J.

    2014-01-01

    Coastal defence structures are proliferating as a result of rising sea levels and stormier seas. With the realisation that most coastal infrastructure cannot be lost or removed, research is required into ways that coastal defence structures can be built to meet engineering requirements, whilst also

  3. Bending analyses for 3D engineered structural panels made from laminated paper and carbon fabric

    Science.gov (United States)

    Jinghao Li; John F. Hunt; Zhiyong Cai; Xianyan Zhou

    2013-01-01

    This paper presents analysis of a 3-dimensional engineered structural panel (3DESP) having a tri-axial core structure made from phenolic impregnated laminated-paper composites with and without high strength composite carbon-fiber fabric laminated to the outside of both faces. Both I-beam equations and finite element method were used to analyze four-point bending of the...

  4. A comparison of damage detection methods applied to civil engineering structures

    DEFF Research Database (Denmark)

    Gres, Szymon; Andersen, Palle; Johansen, Rasmus Johan

    2017-01-01

    Facilitating detection of early-stage damage is crucial for in-time repairs and cost-optimized maintenance plans of civil engineering structures. Preferably, the damage detection is performed by use of output vibration data, hereby avoiding modal identification of the structure. Most of the work...

  5. A comparison of damage detection methods applied to civil engineering structures

    DEFF Research Database (Denmark)

    Gres, Szymon; Andersen, Palle; Johansen, Rasmus Johan

    2018-01-01

    Facilitating detection of early-stage damage is crucial for in-time repairs and cost-optimized maintenance plans of civil engineering structures. Preferably, the damage detection is performed by use of output vibration data, hereby avoiding modal identification of the structure. Most of the work...

  6. Probabilistic model for fatigue crack growth and fracture of welded joints in civil engineering structures

    NARCIS (Netherlands)

    Maljaars, J.; Steenbergen, H.M.G.M.; Vrouwenvelder, A.C.W.M.

    2012-01-01

    This paper presents a probabilistic assessment model for linear elastic fracture mechanics (LEFM). The model allows the determination of the failure probability of a structure subjected to fatigue loading. The distributions of the random variables for civil engineering structures are provided, and

  7. Transactional, Cooperative, and Communal: Relating the Structure of Engineering Engagement Programs with the Nature of Partnerships

    Science.gov (United States)

    Thompson, Julia D.; Jesiek, Brent K.

    2017-01-01

    This paper examines how the structural features of engineering engagement programs (EEPs) are related to the nature of their service-learning partnerships. "Structure" refers to formal and informal models, processes, and operations adopted or used to describe engagement programs, while "nature" signifies the quality of…

  8. Analysis of the Vortex Street Generated at the Core-Bypass Lip of a Jet-Engine Nozzle

    Science.gov (United States)

    Nogueira, José; Legrand, Mathieu; Nauri, Sara; Rodríguez, Pedro A.; Lecuona, Antonio

    The reduction of the noise generated by jet-engine aircrafts is of growing concern in the present society. A better understanding of the aircraft noise production and the development of predictive tools is of great interest. Within this framework, the CoJeN (Coaxial Jet Noise) European Project includes the measurement of the flow field and the noise generated by typical turbofan jet-engine nozzles. One of the many aspects of interest is the occasional presence of acoustic tones of a defined frequency, symptomatic of the presence of quasiperiodic coherent structures within the flow. This chapter analyzes the characteristics of a vortex street in the core-bypass lip of one of the nozzles under study. The measurements were made by means of advanced PIV techniques within the above-mentioned project.

  9. Local damage to reinforced concrete structures caused by impact of aircraft engine missiles. Pt. 1

    International Nuclear Information System (INIS)

    Sugano, T.; Tsubota, H.; Kasai, Y.; Koshika, N.; Ohnuma, H.; Von Riesemann, W.A.; Bickel, D.C.; Parks, M.B.

    1993-01-01

    Structural damage induced by an aircraft crashing into a reinforced concrete structure includes local damage caused by the deformable engines, and global damage caused by the entire aircraft. Local damage to the target may consist of spalling of concrete from its front face together with missile penetration into it, scabbing of concrete from its rear face, and perforation of missile through it. Until now, local damage to concrete structures has been mainly evaluated by rigid missile impact tests. Past research work regarding local damage caused by impact of deformable missiles has been limited. This paper presents the results of a series of impact tests of small-, intermediate-, and full-scale engine models into reinforced concrete panels. The purpose of the tests was to determine the local damage to a reinforced concrete structure caused by the impact of a deformable aircraft engine. (orig.)

  10. Decision of National and Provincial Highway Asphalt Pavement Structure Based on Value Engineering

    Directory of Open Access Journals (Sweden)

    Yingwei Ren

    2014-01-01

    Full Text Available It is important that decision of asphalt pavement structure requires overall considerations of the performance and financial investment. To have asphalt pavement structure fulfilling good reliability, the asphalt pavement structure decision was researched based on value engineering theory. According to the national and provincial highway investigation data in Shandong Province during the last decade, the asphalt pavement performance attenuation rules of traffic levels and asphalt layer thicknesses were developed, and then the road performance evaluation method was presented. In addition, the initial investments, the costs of road maintenance, and middle-scale repair in a period were analyzed. For the light traffic and medium traffic example, using the value engineering method, the pavement performance and costs of which thickness varies from 6 cm to 10 cm were calculated and compared. It was concluded that value engineering was an effective method in deciding the asphalt pavement structure.

  11. Graphite structure and its relation to mechanical engineering design

    International Nuclear Information System (INIS)

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

    1980-01-01

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

  12. Safety Concepts in Structural Glass Engineering : Towards an Integrated Approach

    NARCIS (Netherlands)

    Bos, F.P.

    2009-01-01

    This dissertation proposes the Integrated Approach to Structural Glass Safety, based on four clearly defined element safety properties, damage sensitivity, relative resistance, redundancy, and fracture mode. The Element Safety Diagram (ESD) is introduced to provide an easy-to-read graphical

  13. Aluminium structures in building and civil engineering applications

    NARCIS (Netherlands)

    Soetens, F.

    2010-01-01

    Structural applications of aluminium are considered in this paper. Although the discussion is mainly devoted to Europe, the paper also refers, where possible, to developments in other parts of the world. The problems faced by a designer in creating an optimum design are described, followed by a

  14. 3D engineered fiberboard : a new structural building product

    Science.gov (United States)

    John F. Hunt; Jerrold E. Winandy

    2002-01-01

    To help meet the need for sustainable forest management tools, the USDA Forest Products Laboratory is developing an economically viable process to produce three-dimensional structural fibreboard products that can utilize a wide range of lignocellulosic fibres contained in the forest undergrowth and in underutilized timber. This will encourage the public and private...

  15. Why Software Engineers are Reluctant to Use Structures Methods ...

    African Journals Online (AJOL)

    This paper looks into the reasons for an apparent boycott of theoretically proven structured techniques and methodologies by most developers. It begins by discussing the fact that when a methodology for developing software contradicts with the way human brains solves problems, the result is stress and thence burnout to ...

  16. Fibre Bragg grating sensors for reinforcement corrosion monitoring in civil engineering structures

    International Nuclear Information System (INIS)

    Grattan, S K T; Basheer, P; Taylor, S E; Zhao, W; Sun, T; Grattan, K T V

    2007-01-01

    Fibre optic strain sensors offer a number of advantages over the current electrical resistance type gauges, yet are not widely used in civil engineering applications. The use of fibre optic strain sensors (with a cross comparison with the output of electrical resistance gauges) to monitor the production of corrosion by-products in civil engineering concrete structures containing reinforcement bars has been investigated and results reported

  17. Structural Insights for Engineering Binding Proteins Based on Non-Antibody Scaffolds

    OpenAIRE

    Gilbreth, Ryan N.; Koide, Shohei

    2012-01-01

    Engineered binding proteins derived from non-antibody scaffolds constitute an increasingly prominent class of reagents in both research and therapeutic applications. The growing number of crystal structures of these “alternative” scaffold-based binding proteins in complex with their targets illustrate the mechanisms of molecular recognition that are common among these systems and those unique to each. This information is useful for critically assessing and improving/expanding engineering stra...

  18. Engineering the magnetic structure of Fe clusters by Mn alloying

    Energy Technology Data Exchange (ETDEWEB)

    Longo, R C; Alemany, M M G; Gallego, L J [Departamento de Fisica de la Materia Condensada, Facultad de Fisica, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Vega, A [Departamento de Fisica Teorica, Atomica y Optica, Universidad de Valladolid, E-47011 Valladolid (Spain); Ferrer, J [Departamento de Fisica, Universidad de Oviedo, E-33007 Oviedo (Spain)], E-mail: romadep@usc.es

    2008-06-18

    We propose to tailor the magnetic structure of atomic clusters by suitable doping, which produces the nanometric equivalent to alloying. As a proof of principle, we perform a theoretical analysis of Fe{sub 6-x}Mn{sub x} clusters (x = 0-5), which shows a modulation of the magnetic moment of the clusters as a function of Mn doping and, more importantly, a collinear to noncollinear transition at x = 4.

  19. Structural definition by antibody engineering of an idiotypic determinant.

    Science.gov (United States)

    Sollazzo, M; Castiglia, D; Billetta, R; Tramontano, A; Zanetti, M

    1990-05-01

    Using computer-aided techniques for predicting molecular structure, we constructed an atomic model of the variable domain of a murine anti-thyroglobulin antibody whose immunodominant idiotypic determinant (Id62) was mapped by site-directed mutagenesis and immunochemical analysis. We previously showed that under experimental conditions this idiotype activates anti-idiotypic B cells and T cells, and modulates the response to thyroglobulin in mice. Because idiotype interactions are considered of physiological importance for immune regulation, we studied this idiotype as a model to understand the relationship between function and structure. To determine the contribution of heavy- and light-chain variable domains to the idiotype structure, we constructed chimeric expression vectors and introduced them into the (non-secreting) P3X63Ag8.653 myeloma cell line. Mutants of the heavy-chain variable domain were obtained by site-directed mutagenesis and transfected into the murine (lambda 1) light-chain producer J558L cell line. The expressed proteins were purified from culture supernatants of transfected cells and characterized. We provide evidence that the third hypervariable loop (D region) of the heavy-chain variable domain is the structural correlate of the idiotypic determinant of this autoantibody and is independent from the nature of the associated light chain. Substitution of residues of the first and second complementarity-determining regions do not affect idiotype expression. The results described here are discussed in relation to our understanding, at a molecular level, of the interaction of idiotopes with B- and T-cell compartments.

  20. Experimental analysis of the structure attenuation characteristics on engine noise by pseudo cylinder pressure excitation; Giji tonaiatsu kashin ni yoru engine kozo no soon tokusei hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Ozawa, H.; Nakada, T. [Isuzu Advanced Engineering Center, Tokyo (Japan)

    1997-10-01

    The engine structure attenuation has been experimentally analyzed by the newly developed in-cylinder excitation system. It can reproduce the complete cylinder pressure in non-running engine conditions by adopting the hydraulic and the piezoelectric actuator. The structure attenuation measured in this system has a good coincidence with the ones measured in actually engine operating conditions, meanwhile the current method, which applied only high frequency components as the excitation pressure, was shown to have the unsatisfied agreement. As a result, the proposed system has been concluded to be very useful to estimate the engine noise characteristics in non-running conditions. 4 refs., 11 figs., 1 tab.

  1. Inspection and evaluation of existing structures: a task for brave engineers

    OpenAIRE

    León Gonzalez, Francisco Javier; Corres Peiretti, Hugo; Prieto Aguilera, Francisco

    2008-01-01

    ABSTRACT: Assessing an existing structure implies its in-depth understanding. In the world of Medicine, full understanding of the patient is based on a well studied clinical history, a visual check, analytical tests and, consequently, a comprehensive diagnosis of the causes of the diseases. There is no reason not to apply a similar modus operandi to existing structures. This paper claims for a heller education oT young engineers, to enable them to understand an existing structure as a part of...

  2. Using Model Building in Structural Engineering to Enhance Understanding of Construction Principles and Methods

    Directory of Open Access Journals (Sweden)

    Niall Holmes

    2013-05-01

    Full Text Available This paper presents a new model building exercise in a second year module in the Department of Civil & Structural Engineering in the Dublin Institute of Technology (DIT. The activity aimed to improve students’ understanding of structural engineering, construction principles and methods. It allowed students to practically apply lecture material and construct a scaled model giving them an opportunity to study and visualise a real structure and generate their own ideas on how it should be assembled within a constructivist active learning environment. As a result, lectures were found to be more interactive and students more engaged in the discussions and provided a pathway to bridge the gap between theory (presented in lectures and the reality of their professions, which can aid them in their graduate careers. It is hoped that this type of active learning can be used in other engineering programmes to improve student understanding and as an opportunity to better apply lecture material to the real world.

  3. Theory of Covariance Equivalent ARMAV Models of Civil Engineering Structures

    DEFF Research Database (Denmark)

    Andersen, P.; Brincker, Rune; Kirkegaard, Poul Henning

    In this paper the theoretical background for using covariance equivalent ARMAV models in modal analysis is discussed. It is shown how to obtain a covariance equivalent ARMA model for a univariate linear second order continuous-time system excited by Gaussian white noise. This result is generalize...... for multivariate systems to an ARMAV model. The covariance equivalent model structure is also considered when the number of channels are different from the number of degrees of freedom to be modelled. Finally, it is reviewed how to estimate an ARMAV model from sampled data....

  4. Theory of Covariance Equivalent ARMAV Models of Civil Engineering Structures

    DEFF Research Database (Denmark)

    Andersen, P.; Brincker, Rune; Kirkegaard, Poul Henning

    1996-01-01

    In this paper the theoretical background for using covariance equivalent ARMAV models in modal analysis is discussed. It is shown how to obtain a covariance equivalent ARMA model for a univariate linear second order continous-time system excited by Gaussian white noise. This result is generalized...... for multi-variate systems to an ARMAV model. The covariance equivalent model structure is also considered when the number of channels are different from the number of degrees offreedom to be modelled. Finally, it is reviewed how to estimate an ARMAV model from sampled data....

  5. Design of a System for Monitoring Reliability of Structures and Constructions in Civil Engineering

    Directory of Open Access Journals (Sweden)

    Tomislav S. Igić

    2011-07-01

    Full Text Available Monitoring of civil engineering structures and constructions requires techniques which can produce high precision and accuracy, reliable measurements and fast processing speed. The development of information and communication systems as well as of microprocessor controllers has enabled a creation of monitoring systems that can be used for tracking reliability of structures and constructions in civil engineering, with described key features. This paper describes in detail the architecture of the Civil Engineering Structures Reliability Monitoring (CERM system. The system has been designed for the purposes of the Technical Mechanics and Theory of Constructions Department at the Faculty of Civil Engineering and Architecture, University of Nis. Unlike general commercial monitoring systems, the CERM system has been specially designed for the purpose of reliability monitoring, and its potential will be further exploited in this paper. It is based on usage of universal microprocessor controllers Integraf of series 10X, along with specially designed software package. This system provides real time acquisition of measurements for observed civil engineering structures and analysis of received values based on developed mathematical models.

  6. Variable Geometry and Multicycle Engines

    Science.gov (United States)

    1977-03-01

    AIRCRAFT W. (C. Swan A. D. Welliveri:~G ’.W. Kites S. G. K Ic The Boeing Co(m pany c P. 0. Box 3991) Seattle, Washington 98124 SUMMARY Studies of new... runner -up engines (a P&W advanced duct-burning turbofan, a P&W valved deriva- tive of the duct-burner and two GE engines based on a mixed-flow...margins of superiority, however, are not overwhelmingly large; the runners -up are being retained as backups and will also be described.) In Phase 4 we are

  7. TGP, an extremely stable, non-aggregating fluorescent protein created by structure-guided surface engineering

    OpenAIRE

    Close, Devin W.; Don Paul, Craig; Langan, Patricia S.; Wilce, Matthew C.J.; Traore, Daouda A.K.; Halfmann, Randal; Rocha, Reginaldo C.; Waldo, Geoffery S.; Payne, Riley J.; Rucker, Joseph B.; Prescott, Mark; Bradbury, Andrew R.M.

    2015-01-01

    In this paper we describe the engineering and X-ray crystal structure of Thermal Green Protein (TGP), an extremely stable, highly soluble, non-aggregating green fluorescent protein. TGP is a soluble variant of the fluorescent protein eCGP123, which despite being highly stable, has proven to be aggregation-prone. The X-ray crystal structure of eCGP123, also determined within the context of this paper, was used to carry out rational surface engineering to improve its solubility, leading to TGP....

  8. Performance of the Radioprotection Engineering Group in the new structure of IPEN-CNEN/SP

    International Nuclear Information System (INIS)

    Sahyun, A.; Sordi, G.M.A.A.

    1992-01-01

    A comparison between the old and now CNEN (Brazilian Nuclear Energy Commission) organizational structure was performed. The new structure lead to a new IPEN (Nuclear and Energetics Research Institute) organization and also to gave use to a Radioprotection Engineering Area, The principal modification raised a second block already in accomplishment. The main aim of the Radioprotection Engineering Area is to turn personnel team interested, concerned, dexterous, dynamic and competitive on their activities besides to provide it of a continuously improvement and updating about technical activities in radiation protection. From these results an evaluation of possible drawbacks and ways to overcome them will be performed. (author)

  9. Structural insights for engineering binding proteins based on non-antibody scaffolds.

    Science.gov (United States)

    Gilbreth, Ryan N; Koide, Shohei

    2012-08-01

    Engineered binding proteins derived from non-antibody scaffolds constitute an increasingly prominent class of reagents in both research and therapeutic applications. The growing number of crystal structures of these 'alternative' scaffold-based binding proteins in complex with their targets illustrate the mechanisms of molecular recognition that are common among these systems and those unique to each. This information is useful for critically assessing and improving/expanding engineering strategies. Furthermore, the structural features of these synthetic proteins produced under tightly controlled, directed evolution deepen our understanding of the underlying principles governing molecular recognition. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Nonlinear dynamic soil-structure interaction in earthquake engineering

    International Nuclear Information System (INIS)

    Nieto-Ferro, Alex

    2013-01-01

    The present work addresses a computational methodology to solve dynamic problems coupling time and Laplace domain discretizations within a domain decomposition approach. In particular, the proposed methodology aims at meeting the industrial need of performing more accurate seismic risk assessments by accounting for three-dimensional dynamic soil-structure interaction (DSSI) in nonlinear analysis. Two subdomains are considered in this problem. On the one hand, the linear and unbounded domain of soil which is modelled by an impedance operator computed in the Laplace domain using a Boundary Element (BE) method; and, on the other hand, the superstructure which refers not only to the structure and its foundations but also to a region of soil that possibly exhibits nonlinear behaviour. The latter sub-domain is formulated in the time domain and discretized using a Finite Element (FE) method. In this framework, the DSSI forces are expressed as a time convolution integral whose kernel is the inverse Laplace transform of the soil impedance matrix. In order to evaluate this convolution in the time domain by means of the soil impedance matrix (available in the Laplace domain), a Convolution Quadrature-based approach called the Hybrid Laplace-Time domain Approach (HLTA), is thus introduced. Its numerical stability when coupled to Newmark time integration schemes is subsequently investigated through several numerical examples of DSSI applications in linear and nonlinear analyses. The HLTA is finally tested on a more complex numerical model, closer to that of an industrial seismic application, and good results are obtained when compared to the reference solutions. (author)

  11. Vibration-based health monitoring and model refinement of civil engineering structures

    Energy Technology Data Exchange (ETDEWEB)

    Farrar, C.R.; Doebling, S.W.

    1997-10-01

    Damage or fault detection, as determined by changes in the dynamic properties of structures, is a subject that has received considerable attention in the technical literature beginning approximately 30 years ago. The basic idea is that changes in the structure`s properties, primarily stiffness, will alter the dynamic properties of the structure such as resonant frequencies and mode shapes, and properties derived from these quantities such as modal-based flexibility. Recently, this technology has been investigated for applications to health monitoring of large civil engineering structures. This presentation will discuss such a study undertaken by engineers from New Mexico Sate University, Sandia National Laboratory and Los Alamos National Laboratory. Experimental modal analyses were performed in an undamaged interstate highway bridge and immediately after four successively more severe damage cases were inflicted in the main girder of the structure. Results of these tests provide insight into the abilities of modal-based damage ID methods to identify damage and the current limitations of this technology. Closely related topics that will be discussed are the use of modal properties to validate computer models of the structure, the use of these computer models in the damage detection process, and the general lack of experimental investigation of large civil engineering structures.

  12. Full scale technology demonstration of a modern counterrotating unducted fan engine concept: Component test

    Science.gov (United States)

    1987-01-01

    The UDF trademark (Unducted Fan) engine is a new aircraft engine concept based on an ungeared, counterrotating, unducted, ultra-high-bypass turbofan configuration. This engine is being developed to provide a high thrust-to-weight ratio powerplant with exceptional fuel efficiency for subsonic aircraft application. This report covers the testing of pertinent components of this engine such as the fan blades, control and actuation system, turbine blades and spools, seals, and mixer frame.

  13. Engineering excellence at Rolls-Royce; a taste of English culture

    OpenAIRE

    Schnelders, J.

    2013-01-01

    Rolls-Royce is one of the most well-known brands in the world and synonymous with the highest engineering quality. Amongst Aerospace Engineers, Rolls-Royce is directly associated with the Trent turbofan aircraft engines. The engines power the world’s newest passenger aircraft, including the Boeing 787 Dreamliner and the large Airbus A380. A Rolls-Royce powered aircraft takes o! or lands every 2.5 seconds.

  14. 1st International Conference on Hydraulic Design in Water Resources Engineering : Channels and Channel Control Structures

    CERN Document Server

    1984-01-01

    The development of water resources has proceeded at an amazing speed around the world in the last few decades. The hydraulic engineer has played his part: in constructing much larger artificial channels than ever before, larger and more sophisticated control structures, and systems of irrigation, drainage and water supply channels in which the flow by its nature is complex and unsteady requiring computer-based techniques at both the design and operation stage. It seemed appropriate to look briefly at some of the developments in hydraulic design resulting from this situation. Hence the idea of the Conference was formed. The Proceedings of the Conference show that hydraulic engineers have been able to acquire a very substantial base of design capability from the experience of the period referred to. The most outstanding development to have occurred is in the combination of physical and mathematical modelling, which in hydraulic engineering has followed a parallel path to that in other branches of engineering sc...

  15. Fuel structure effects on HC emissions from a spark-ignited engine

    International Nuclear Information System (INIS)

    Kaiser, E.W.; Siegl, W.O.; Henig, Y.I.; Anderson, R.W.; Trinker, F.H.

    1992-01-01

    This paper reports that tailpipe emissions are a critical consideration in the design process of automobiles because of government regulations based on environmental concerns. To meet these standards, the combined effects of engine design, catalyst design, and fuel composition on regulation emissions must be understood. The effects of variable related to engine design (e.g. crevice volumes, oil films, and fuel-air equivalence ratio) on hydrocarbon (HC) emissions have been investigated. However, systematic studies of the effect of fuel composition on emissions have not been pursued as thoroughly. In particular, no extensive experiments have been performed using pure fuels in the same engine in order to carefully compare the effect of fuel structure on emissions under nearly identical engine operating conditions

  16. Ice Crystal Icing Engine Testing in the NASA Glenn Research Center's Propulsion Systems Laboratory: Altitude Investigation

    Science.gov (United States)

    Oliver, Michael J.

    2014-01-01

    The National Aeronautics and Space Administration (NASA) conducted a full scale ice crystal icing turbofan engine test using an obsolete Allied Signal ALF502-R5 engine in the Propulsion Systems Laboratory (PSL) at NASA Glenn Research Center. The test article used was the exact engine that experienced a loss of power event after the ingestion of ice crystals while operating at high altitude during a 1997 Honeywell flight test campaign investigating the turbofan engine ice crystal icing phenomena. The test plan included test points conducted at the known flight test campaign field event pressure altitude and at various pressure altitudes ranging from low to high throughout the engine operating envelope. The test article experienced a loss of power event at each of the altitudes tested. For each pressure altitude test point conducted the ambient static temperature was predicted using a NASA engine icing risk computer model for the given ambient static pressure while maintaining the engine speed.

  17. Earthquake engineering and structural dynamics studies at Bhabha Atomic Research Centre

    International Nuclear Information System (INIS)

    Reddy, G.R.; Parulekar, Y.M.; Sharma, A.; Dubey, P.N.; Vaity, K.N.; Kukreja, Mukhesh; Vaze, K.K.; Ghosh, A.K.; Kushwaha, H.S.

    2007-01-01

    Earthquake Engineering and structural Dynamics has gained the attention of many researchers throughout the world and extensive research work is performed. Linear behaviour of structures, systems and components (SSCs) subjected to earthquake/dynamic loading is clearly understood. However, nonlinear behaviour of SSCs subjected to earthquake/dynamic loading need to be understood clearly and design methods need to be validated experimentally. In view of this, three major areas in earthquake engineering and structural dynamics identified for research includes: design and development of passive devices to control the seismic/dynamic response of SSCs, nonlinear behaviour of piping systems subjected to earthquake loading and nonlinear behavior of RCC structures under seismic excitation or dynamic loading. BARC has performed extensive work and also being continued in the above-identified areas. The work performed is helping for clearer understanding of nonlinear behavior of SSCs as well as in developing new schemes, methodologies and devices to control the earthquake response of SSCs. (author)

  18. Nanoporous Anodic Alumina Platforms: Engineered Surface Chemistry and Structure for Optical Sensing Applications

    Directory of Open Access Journals (Sweden)

    Tushar Kumeria

    2014-07-01

    Full Text Available Electrochemical anodization of pure aluminum enables the growth of highly ordered nanoporous anodic alumina (NAA structures. This has made NAA one of the most popular nanomaterials with applications including molecular separation, catalysis, photonics, optoelectronics, sensing, drug delivery, and template synthesis. Over the past decades, the ability to engineer the structure and surface chemistry of NAA and its optical properties has led to the establishment of distinctive photonic structures that can be explored for developing low-cost, portable, rapid-response and highly sensitive sensing devices in combination with surface plasmon resonance (SPR and reflective interference spectroscopy (RIfS techniques. This review article highlights the recent advances on fabrication, surface modification and structural engineering of NAA and its application and performance as a platform for SPR- and RIfS-based sensing and biosensing devices.

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

    International Nuclear Information System (INIS)

    Buckley, J.D.

    1992-10-01

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

  20. Engineering Discourse in the Structure of the ESP Training at Southern Federal University

    Science.gov (United States)

    Sidelnik, Ellina; Melnik, Olga; Burenko, Lyudmila

    2016-01-01

    This paper discusses the essentials of engineering discourse in the structure of the ESP training at Southern Federal University (SFU) (Taganrog, Russia). The purpose of this paper is to justify critical rethinking of existing programs of technical students training in foreign languages at SFU taking into account the increasing role of engineering…

  1. A Self-Ethnographic Investigation of Continuing Education Program in Engineering Arising from Economic Structural Change

    Science.gov (United States)

    Kaihlavirta, Auri; Isomöttönen, Ville; Kärkkäinen, Tommi

    2015-01-01

    This paper provides a self-ethnographic investigation of a continuing education program in engineering in Central Finland. The program was initiated as a response to local economic structural change, in order to offer re-education possibilities for a higher educated workforce currently under unemployment threat. We encountered considerable…

  2. Identification of Time Varying Civil Engineering Structures using Multivariate Recursive Time Domain Models

    DEFF Research Database (Denmark)

    Andersen, P.; Skjærbæk, P. S.; Kirkegaard, Poul Henning

    with the smoothed quanties which have been obtained from SARCOF. The results show the usefulness of the technique for identification of a time varying civil engineering structure. It is found that all the techniques give reliable estiates of the frequencies of the two lowest modes and the first mode shape. Only...

  3. Use of Statistical Information for Damage Assessment of Civil Engineering Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Andersen, P.

    This paper considers the problem of damage assessment of civil engineering structures using statistical information. The aim of the paper is to review how researchers recently have tried to solve the problem. It is pointed out that the problem consists of not only how to use the statistical...

  4. On the Uncertainty of Identification of Civil Engineering Structures Using ARMA Models

    DEFF Research Database (Denmark)

    Andersen, Palle; Brincker, Rune; Kirkegaard, Poul Henning

    1995-01-01

    In this paper the uncertainties of modal parameters estimated using ARMA models for identification of civil engineering structures are investigated. How to initialize the predictor part of a Gauss-Newton optimization algorithm is put in focus. A backward-forecasting procedure for initialization...

  5. On the Uncertainty of Identification of Civil Engineering Structures using ARMA Models

    DEFF Research Database (Denmark)

    Andersen, P.; Brincker, Rune; Kirkegaard, Poul Henning

    In this paper the uncertainties of modal parameters estimated using ARMA models for identification of civil engineering structures are investigated. How to initialize the predictor part of a Gauss-Newton optimization algorithm is put in focus. A backward-forecasting procedure for initialization...

  6. Application of Composite Structures in Bridge Engineering. Problems of Construction Process and Strength Analysis

    Directory of Open Access Journals (Sweden)

    Flaga Kazimierz

    2015-03-01

    Full Text Available Steel-concrete composite structures have been used in bridge engineering from decades. This is due to rational utilisation of the strength properties of the two materials. At the same time, the reinforced concrete (or prestressed deck slab is more favourable than the orthotropic steel plate used in steel bridges (higher mass, better vibration damping, longer life.

  7. The reliability of structural systems operating at high temperature: Replacing engineering judgement with operational experience

    International Nuclear Information System (INIS)

    Chevalier, M.J.; Smith, D.J.; Dean, D.W.

    2012-01-01

    Deterministic assessments are used to assess the integrity of structural systems operating at high temperature by providing a lower bound lifetime prediction, requiring considerable engineering judgement. However such a result may not satisfy the structural integrity assessment purpose if the results are overly conservative or conversely plant observations (such as failures) could undermine the assessment result if observed before the lower bound lifetime. This paper develops a reliability methodology for high temperature assessments and illustrates the impact and importance of managing the uncertainties within such an analysis. This is done by separating uncertainties into three classifications; aleatory uncertainty, quantifiable epistemic uncertainty and unquantifiable epistemic uncertainty. The result is a reliability model that can predict the behaviour of a structural system based upon plant observations, including failure and survival data. This can be used to reduce the over reliance upon engineering judgement which is prevalent in deterministic assessments. Highlights: ► Deterministic assessments are shown to be heavily reliant upon engineering judgment. ► Based upon the R5 procedure, a reliability model for a structural system is developed. ► Variables must be classified as either aleatory or epistemic to model their impact on reliability. ► Operation experience is then used to reduce reliance upon engineering judgment. ► This results in a model which can predict system behaviour and learn from operational experience.

  8. Characterization and Simulation of Time-Dependent Response of Structural Materials for Aero Structures and Turbine Engines (Postprint)

    Science.gov (United States)

    2017-03-31

    Division at the Materials & Manufacturing Directorate whose research and dedication have been instrumental in affecting the design and life management...capability. It is the decrease of capability as a function of time/usage/exposure that must be understood and predicted to optimize the design and life ...and life management strategies of aerospace components that comprise aircraft structures and turbine engines. Historically predictive models in these

  9. Numerical modeling of interaction of the aircraft engine with concrete protective structures

    Science.gov (United States)

    Radchenko, P. A.; Batuev, S. P.; Radchenko, A. V.; Plevkov, V. S.

    2018-01-01

    The paper presents numerical modeling results considering interaction of Boeing 747 aircraft engine with nuclear power station protective shell. Protective shell has been given as a reinforced concrete structure with complex scheme of reinforcement. The engine has been simulated by cylinder projectile made from titanium alloy. The interaction velocity has comprised 180 m/s. The simulation is three-dimensional solved by finite element method using the author’s own software package EFES. Fracture and fragmentation of materials have been considered in calculations. Program software has been assessed to be used in calculation of multiple-contact objectives.

  10. Local damage to reinforced concrete structures caused by impact of aircraft engine missiles. Pt. 2

    International Nuclear Information System (INIS)

    Sugano, T.; Tsubota, H.; Kasai, Y.; Koshika, N.; Itoh, C.; Shirai, K.; Von Riesemann, W.A.; Bickel, D.C.; Parks, M.B.

    1993-01-01

    Three sets of impact tests, small-, intermediate-, and full-scale tests, have been executed to determine local damage to reinforced concrete structures caused by the impact of aircraft engine missiles. The results of the test program showed that (1) the use of the similarity law is appropriate, (2) suitable empirical formulas exist for predicting the local damage caused by rigid missiles, (3) reduction factors may be used for evaluating the reduction in local damage due to the deformability of the engines, (4) the reinforcement ratio has no effect on local damage, and (5) the test results could be adequately predicted using nonlinear response analysis. (orig.)

  11. A Paperless Course on Structural Engineering Programming: Investing in Educational Technology in the Times of the Greek Financial Recession

    Science.gov (United States)

    Sextos, Anastasios G.

    2014-01-01

    This paper presents the structure of an undergraduate course entitled "programming techniques and the use of specialised software in structural engineering" which is offered to the fifth (final) year students of the Civil Engineering Department of Aristotle University Thessaloniki in Greece. The aim of this course is to demonstrate the…

  12. An innovative bio-engineering retaining structure for supporting unstable soil

    Directory of Open Access Journals (Sweden)

    Gianluca Bella

    2017-04-01

    Full Text Available The paper presents a new prefabricated bio-engineering structure for the support of unstable soil. This prefabricated structure is made of a steel frame which is completely filled with soil and a face made of tree trunks among which scions or autochthonous bushes are planted. Due to the difficulties in interpreting the complex interaction between soil and structure during the installation and lifetime, an in situ test was carried out in order to evaluate the state of stress in the steel frame and to understand the global behavior of the structure under service loads. On the basis of the obtained results, a procedure for checking the structure safety was proposed and discussed. An easy design method was developed during the research. Moreover, the use of this type of prefabricated structure shows several advantages, such as good performances in terms of stabilizing effects, and easy assembly and transport.

  13. Fuel nozzle assembly for use as structural support for a duct structure in a combustor of a gas turbine engine

    Science.gov (United States)

    Wiebe, David J; Fox, Timothy A

    2015-03-31

    A fuel nozzle assembly for use in a combustor apparatus of a gas turbine engine. An outer housing of the fuel nozzle assembly includes an inner volume and provides a direct structural connection between a duct structure and a fuel manifold. The duct structure defines a flow passage for combustion gases flowing within the combustor apparatus. The fuel manifold defines a fuel supply channel therein in fluid communication with a source of fuel. A fuel injector of the fuel nozzle assembly is provided in the inner volume of the outer housing and defines a fuel passage therein. The fuel passage is in fluid communication with the fuel supply channel of the fuel manifold for distributing the fuel from the fuel supply channel into the flow passage of the duct structure.

  14. 3D multi-layered fibrous cellulose structure using an electrohydrodynamic process for tissue engineering.

    Science.gov (United States)

    Kim, Minseong; Kim, GeunHyung

    2015-11-01

    Micro/nanofibrous structures have been applied widely in various tissue-engineering applications because the topological structures are similar to the extracellular matrix (ECM), which encourages a high degree of cell adhesion and growth. However, it has been difficult to produce a three-dimensional (3D) fibrous structure using controllable macro-pores. Recently, cellulose has been considered a high-potential natural-origin biomaterial, but its use in 3D biomedical structures has been limited due to its narrow processing window. Here, we suggest a new 3D cellulose scaffold consisting of multi-layered struts made of submicron-sized entangled fibers that were fabricated using an electrohydrodynamic direct jet (EHDJ) process that is spin-printing. By optimizing processing conditions (electric field strength, cellulose feeding rate, and distance between nozzle and target), we can achieve a multi-layered cellulose structure consisting of the cylindrically entangled cellulose fibers. To compare the properties of the fabricated 3D cellulose structure, we used a PCL fibrous scaffold, which has a similar fibrous morphology and pore geometry, as a control. The physical and in vitro biocompatibilities of both fibrous scaffolds were assessed using human dermal fibroblasts, and the cellulose structure showed higher cell adhesion and metabolic activities compared with the control. These results suggest the EHDJ process to be an effective fabricating tool for tissue engineering and the cellulose scaffold has high potential as a tissue regenerative material. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Integrated engine-generator concept for aircraft electric secondary power

    Science.gov (United States)

    Secunde, R. R.; Macosko, R. P.; Repas, D. S.

    1972-01-01

    The integrated engine-generator concept of locating an electric generator inside an aircraft turbojet or turbofan engine concentric with, and driven by, one of the main engine shafts is discussed. When properly rated, the generator can serve as an engine starter as well as a generator of electric power. The electric power conversion equipment and generator controls are conveniently located in the aircraft. Preliminary layouts of generators in a large engine together with their physical sizes and weights indicate that this concept is a technically feasible approach to aircraft secondary power.

  16. Challenges in engineering osteochondral tissue grafts with hierarchical structures Ivana Gadjanski, Gordana Vunjak Novakovic

    Science.gov (United States)

    Gadjanski, Ivana; Vunjak-Novakovic, Gordana

    2015-01-01

    Introduction A major hurdle in treating osteochondral (OC) defects are the different healing abilities of two types of tissues involved - articular cartilage and subchondral bone. Biomimetic approaches to OC-construct-engineering, based on recapitulation of biological principles of tissue development and regeneration, have potential for providing new treatments and advancing fundamental studies of OC tissue repair. Areas covered This review on state of the art in hierarchical OC tissue graft engineering is focused on tissue engineering approaches designed to recapitulate the native milieu of cartilage and bone development. These biomimetic systems are discussed with relevance to bioreactor cultivation of clinically sized, anatomically shaped human cartilage/bone constructs with physiologic stratification and mechanical properties. The utility of engineered OC tissue constructs is evaluated for their use as grafts in regenerative medicine, and as high-fidelity models in biological research. Expert opinion A major challenge in engineering OC tissues is to generate a functionally integrated stratified cartilage-bone structure starting from one single population of mesenchymal cells, while incorporating perfusable vasculature into the bone, and in bone-cartilage interface. To this end, new generations of advanced scaffolds and bioreactors, implementation of mechanical loading regimens, and harnessing of inflammatory responses of the host will likely drive the further progress. PMID:26195329

  17. Laser Scanning in Engineering Surveying: Methods of Measurement and Modeling of Structures

    Directory of Open Access Journals (Sweden)

    Lenda Grzegorz

    2016-06-01

    Full Text Available The study is devoted to the uses of laser scanning in the field of engineering surveying. It is currently one of the main trends of research which is developed at the Department of Engineering Surveying and Civil Engineering at the Faculty of Mining Surveying and Environmental Engineering of AGH University of Science and Technology in Krakow. They mainly relate to the issues associated with tower and shell structures, infrastructure of rail routes, or development of digital elevation models for a wide range of applications. These issues often require the use of a variety of scanning techniques (stationary, mobile, but the differences also regard the planning of measurement stations and methods of merging point clouds. Significant differences appear during the analysis of point clouds, especially when modeling objects. Analysis of the selected parameters is already possible basing on ad hoc measurements carried out on a point cloud. However, only the construction of three-dimensional models provides complete information about the shape of structures, allows to perform the analysis in any place and reduces the amount of the stored data. Some structures can be modeled in the form of simple axes, sections, or solids, for others it becomes necessary to create sophisticated models of surfaces, depicting local deformations. The examples selected for the study allow to assess the scope of measurement and office work for a variety of uses related to the issue set forth in the title of this study. Additionally, the latest, forward-looking technology was presented - laser scanning performed from Unmanned Aerial Vehicles (drones. Currently, it is basically in the prototype phase, but it might be expected to make a significant progress in numerous applications in the field of engineering surveying.

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

    Science.gov (United States)

    Stekolschik, Alexander, Prof.

    2017-10-01

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

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

    Science.gov (United States)

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

    2016-03-01

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

  20. Joint application of non-invasive techniques to characterize the dynamic behaviuor of engineering structures

    Science.gov (United States)

    Gallipoli, M. R.; Perrone, A.; Stabile, T. A.; Ponzo, F. C.; Ditommaso, R.

    2012-04-01

    The systematic monitoring of strategic civil infrastructures such as bridges, large dams or high-rise buildings in order to ensure their structural stability is a strategic issue particularly in earthquake-prone regions. Nevertheless, in areas less exposed to seismic hazard, the monitoring is also an important tool for civil engineers, for instance if they have to deal with structures exposed to heavy operational demands for extended periods of time and whose structural integrity might be in question or at risk. A continuous monitoring of such structures allows the identification of their fundamental response characteristics and the changes of these over time, the latter representing indicators for potential structural degradation. The aim of this paper is the estimation of fundamental dynamic parameters of some civil infrastructures by the joint application of fast executable, non-invasive techniques such as the Ambient Noise Standard Spectral Ratio, and Ground-Based microwave Radar Interferometer techniques. The joint approach combine conventional, non-conventional and innovative techniques in order to set up a non destructive evaluation procedure allowing for a multi-sensing monitoring at a multi-scale and multi-depth levels (i.e. with different degrees of spatial resolution and different subsurface depths). In particular, techniques based on ambient vibration recordings have become a popular tool for characterizing the seismic response and state-of-health of strategic civil infrastructure. The primary advantage of these approaches lies in the fact that no transient earthquake signals or even active excitation of the structure under investigation are required. The microwave interferometry radar technology, it has proven to be a powerful remote sensing tool for vibration measurement of structures, such as bridge, heritage architectural structures, vibrating stay cables, and engineering structures. The main advantage of this radar technique is the possibility to

  1. Hierarchical Structure of Articular Bone-Cartilage Interface and Its Potential Application for Osteochondral Tissue Engineering

    Science.gov (United States)

    Bian, Weiguo; Qin, Lian; Li, Dichen; Wang, Jin; Jin, Zhongmin

    2010-09-01

    The artificial biodegradable osteochondral construct is one of mostly promising lifetime substitute in the joint replacement. And the complex hierarchical structure of natural joint is important in developing the osteochondral construct. However, the architecture features of the interface between cartilage and bone, in particular those at the micro-and nano-structural level, remain poorly understood. This paper investigates these structural data of the cartilage-bone interface by micro computerized tomography (μCT) and Scanning Electron Microscope (SEM). The result of μCT shows that important bone parameters and the density of articular cartilage are all related to the position in the hierarchical structure. The conjunctions of bone and cartilage were defined by SEM. All of the study results would be useful for the design of osteochondral construct further manufactured by nano-tech. A three-dimensional model with gradient porous structure is constructed in the environment of Pro/ENGINEERING software.

  2. Engineering design and fabrication of tapered damped X-Band accelerating structures

    CERN Document Server

    Solodko, A; Gudkov, D; Riddone, G; Grudiev, A; Atieh, S; Taborelli, M

    2011-01-01

    The accelerating structures (AS) are one of the main components of the Compact LInear Collider (CLIC), under study at CERN. Each accelerating structure contains about 30 copper discs, which form the accelerating cavity. The requirements of different technical systems, such as vacuum and cooling, have to be considered during the engineering design. A fully featured AS is very challenging and requires several technologies. Different damping methods, waveguides, vacuum manifolds, slots and chokes, result in various design configurations. In the CLIC AS each cell is damped by means of four waveguides coupled to the cell. The vacuum manifolds combine a number of functions such as damping, vacuum pumping and cooling. A silicon carbide absorber, fixed inside of each manifold, is required for effective damping of Higher Order Modes (HOMs). This paper describes the engineering design of the X-band AS with damping material, and focuses on few technical solutions.

  3. List of soils, soil-structure interaction and other related computer programs available for LMVD engineers

    Science.gov (United States)

    Radhakrishnan, N.; Senter, P. K.

    1981-05-01

    This report presents a list of soils, soil-structure interaction, and other related computer programs available for engineers of the Lower Mississippi Valley Division. Programs for use in the following subject areas are listed: T-walls; slope stability; piles; sheet piles, and cells; seepage; stress computation, settlement, and consolidation; piezometer data; instrumentation and laboratory data; plotting programs; finite element and finite difference methods; earthquakes and dynamics; and others. Also included are abstracts of some of the listed programs.

  4. Optimal Design of Experiments for Parametric Identification of Civil Engineering Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning

    Optimal Systems of experiments for parametric identification of civil engineering structures is investigated. Design of experiments for parametric identification of dynamic systems is usually done by minimizing a scalar measure, e.g the determinant, the trace ect., of an estimated parameter covar...... covariance matrix, based on prior knowledge. The experimental conditions available for adjustment, considering in this thesis, are input signal, sampling rate, the location of sensors and number of sensors....

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

    Science.gov (United States)

    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

  6. Aero Engine Component Fault Diagnosis Using Multi-Hidden-Layer Extreme Learning Machine with Optimized Structure

    Directory of Open Access Journals (Sweden)

    Shan Pang

    2016-01-01

    Full Text Available A new aero gas turbine engine gas path component fault diagnosis method based on multi-hidden-layer extreme learning machine with optimized structure (OM-ELM was proposed. OM-ELM employs quantum-behaved particle swarm optimization to automatically obtain the optimal network structure according to both the root mean square error on training data set and the norm of output weights. The proposed method is applied to handwritten recognition data set and a gas turbine engine diagnostic application and is compared with basic ELM, multi-hidden-layer ELM, and two state-of-the-art deep learning algorithms: deep belief network and the stacked denoising autoencoder. Results show that, with optimized network structure, OM-ELM obtains better test accuracy in both applications and is more robust to sensor noise. Meanwhile it controls the model complexity and needs far less hidden nodes than multi-hidden-layer ELM, thus saving computer memory and making it more efficient to implement. All these advantages make our method an effective and reliable tool for engine component fault diagnosis tool.

  7. Structural integrity for DEMO: An opportunity to close the gap from materials science to engineering needs

    Energy Technology Data Exchange (ETDEWEB)

    Porton, M., E-mail: michael.porton@ccfe.ac.uk [CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Wynne, B.P. [CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); University of Sheffield, Sheffield, South Yorkshire S10 2TN (United Kingdom); Bamber, R.; Hardie, C.D.; Kalsey, M. [CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)

    2016-11-01

    Highlights: • Key shortfalls in the current approaches to verification of structural integrity are outlined. • Case studies for high integrity applications in other demanding environments are examined. • Relevant lessons are drawn from fission and space for the design stage and through service life. • Future efforts are suggested to align materials and engineering for DEMO structural integrity. - Abstract: It is clear that fusion demonstration devices offer unique challenges due to the myriad, interacting material degradation effects and the numerous, conflicting requirements that must be addressed in order for in-vessel components to deliver satisfactory performance over the required lifetime. The link between mechanical engineering and materials science is pivotal to assure the timely realisation and exploitation of successful fusion power. A key aspect of this link is the verification of structural integrity, achieved at the design stage via structural design criteria against which designs are judged to be sufficiently resilient (or not) to failure, for a given set of loading conditions and desired lifetime. As various demonstration power plant designs progress through their current conceptual design phases, this paper seeks to highlight key shortfalls in this vital link between engineering needs and materials science, offering a perspective on where future attention can be prioritised to maximise impact. Firstly, issues in applying existing structural design criteria to demonstration power plant designs are identified. Whilst fusion offers particular challenges, there are significant insights to be gained from attempts to address such issues for high performance, high integrity applications in other demanding environments. Therefore case studies from beyond fusion are discussed. These offer examples where similar shortfalls have been successfully addressed, via approaches at the design stage and through service lifetime in order to deliver significant

  8. Nano-structured polymer scaffolds for tissue engineering and regenerative medicine

    Science.gov (United States)

    Smith, I.O.; Liu, X.H.; Smith, L.A.; Ma, P.X.

    2009-01-01

    The structural features of tissue engineering scaffolds affect cell response and must be engineered to support cell adhesion, proliferation and differentiation. The scaffold acts as an interim synthetic extracellular matrix (ECM) that cells interact prior to forming new tissue. In this review, bone tissue engineering is used as the primary example because of our group’s focus and for the sake of brevity. We focus on nano-fibrous scaffolds and the incorporation of other components including other nanofeatures into the scaffold structure. Since the ECM is comprised in large part of collagen fibers, between 50–500 nm in diameter, well-designed nano-fibrous scaffolds mimic this structure. Our group has developed a novel thermally-induced phase separation (TIPS) process in which a solution of biodegradable polymer is cast into a porous scaffold, resulting in a nano-fibrous pore-wall structure. These nano-scale fibers have a diameter (50–500 nm) comparable to those collagen fibers found in the ECM. This process can then be combined with a porogen leaching technique, also developed by our group, to engineer an interconnected pore structure that promotes cell migration and tissue ingrowth in three dimensions. To improve upon efforts to incorporate a ceramic component into polymer scaffolds by mixing, our group has also developed a technique where apatite crystals are grown onto biodegradable polymer scaffolds by soaking them in simulated body fluid (SBF). By changing the polymer used, the concentration of ions in the SBF and by varying the treatment time, the size and distribution of these crystals is varied. Work is currently being done to improve the distribution of these crystals throughout three-dimensional scaffolds and to create nano-scale apatite deposits that better mimic those found in the ECM. In both nano-fibrous and composite scaffolds, cell adhesion, proliferation and differentiation improved when compared to control scaffolds. Additionally, composite

  9. Structurally-compliant rocket engine combustion chamber: Experimental/analytical validation

    Science.gov (United States)

    Jankovsky, R. S.; Kazaroff, J. M.; Galford, G. R.; Arya, V. K.

    1993-11-01

    A new, structurally-compliant rocket engine combustion chamber design has been validated through analysis and experiment. Subscale, tubular channel chambers have been cyclically tested, and analytically evaluated. Cyclic lives were determined to have a potential for 1000 percent increase in life over that of rectangular channel designs, the current state-of-the-art. Greater structural compliance in the circumferential direction gives rise to lower thermal strains during hot firing, resulting in lower thermal strain ratcheting and longer predicted fatigue lives. Thermal/durability analyses of the combustion chamber design, involving cyclic temperatures, strains, and low-cycle fatigue lives have corroborated the experimental observations.

  10. Vibration Based Damage Assessment of a Civil Engineering Structures using a Neural Networks

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Rytter, A.

    In this paper the possibility of using a Multilayer Perceptron (MLP) network trained with the Backpropagation Algorith as a non-destructive damage assessment technique to locate and quantify a damage in Civil Engineering structures is investigated. Since artificial neural networks are proving...... to be an effective tool for pattern recognition, the basic idea is to train a neural network with simulated values of modal parameters in order to recognize the behaviour of the damaged as well as the undamaged structure. Subjecting this trained neural network to measured modal parameters should imply information...

  11. Optimization of Air-Breathing Engine Concept

    Science.gov (United States)

    Patnaik, Surya N.; Lavelle, Thomas M.; Hopkins, Dale A.

    1996-01-01

    The design optimization of air-breathing propulsion engine concepts has been accomplished by soft-coupling the NASA Engine Performance Program (NEPP) analyzer with the NASA Lewis multidisciplinary optimization tool COMETBOARDS. Engine problems, with their associated design variables and constraints, were cast as nonlinear optimization problems with thrust as the merit function. Because of the large number of mission points in the flight envelope, the diversity of constraint types, and the overall distortion of the design space; the most reliable optimization algorithm available in COMETBOARDS, when used by itself, could not produce satisfactory, feasible, optimum solutions. However, COMETBOARDS' unique features-which include a cascade strategy, variable and constraint formulations, and scaling devised especially for difficult multidisciplinary applications-successfully optimized the performance of subsonic and supersonic engine concepts. Even when started from different design points, the combined COMETBOARDS and NEPP results converged to the same global optimum solution. This reliable and robust design tool eliminates manual intervention in the design of air-breathing propulsion engines and eases the cycle analysis procedures. It is also much easier to use than other codes, which is an added benefit. This paper describes COMETBOARDS and its cascade strategy and illustrates the capabilities of the combined design tool through the optimization of a high-bypass- turbofan wave-rotor-topped subsonic engine and a mixed-flow-turbofan supersonic engine.

  12. The supersonic fan engine: An advanced concept in supersonic cruise propulsion

    Science.gov (United States)

    Franciscus, L. C.

    1981-01-01

    Engine performance and mission studies were carried out for turbofan engines equipped with supersonic through-flow fans. The mission was for a commercial supersonic transport with a Mach 2.32 capability. The advantages of the supersonic fan engines are discussed in terms of mission range comparisons with other engine types. The effects of fan efficiency, inlet losses, and engine weight on engine performance and mission range are shown. The range of a supersonic transport with supersonic fan engines could be 10 to 20 percent better than with other types having the same technology core.

  13. Unmanned aerial vehicle (UAV) application to the structural health assessment of large civil engineering structures

    Science.gov (United States)

    Castiglioni, Carlo A.; Rabuffetti, Angelo S.; Chiarelli, Gian P.; Brambilla, Giovanni; Georgi, Julia

    2017-09-01

    This paper summarizes the experience gained in the structural assessment of an existing Thermal Power Plant (TPP) located near Pristina, focusing on the cooling tower and the flue gas stack, which are the main structures of the TPP. Scope of the work was the evaluation of the actual conditions of the structures and to identify the eventual repair measures in order to guarantee a safe and reliable operation of the TPP in view of the extension of its operational lifetime for the next 30 years. With this aim, a sequence of different activities was performed, like: a topographic survey to compare the actual geometrical configuration with the design one, an investigation of the material properties, an in depth visual inspection in order to detect any visible existing damage. Due to the very high elevations of the constructions and to the lack of appropriate structures aimed to their inspections and maintenance, this activity could not be performed without using Unmanned Aerial Vehicle (UAV). This resulted the safest, most economical and less time-consuming solution identified to map the surface damage in the reinforced concrete elements of these large structures including zones that could not be inspected because out of reach by other means.

  14. Local damage to Ultra High Performance Concrete structures caused by an impact of aircraft engine missiles

    International Nuclear Information System (INIS)

    Riedel, Werner; Noeldgen, Markus; Strassburger, Elmar; Thoma, Klaus; Fehling, Ekkehard

    2010-01-01

    Research highlights: → Experimental series on UHPC panels subjected to aircraft engine impact. → Improved ballistic limit of fiber reinforced UHPC in comparison to conventional R/C. → Detailed investigation of failure mechanisms of fiber reinforced UHPC panel. - Abstract: The impact of an aircraft engine missile causes high stresses, deformations and a severe local damage to conventional reinforced concrete. As a consequence the design of R/C protective structural elements results in components with rather large dimensions. Fiber reinforced Ultra High Performance Concrete (UHPC) is a concrete based material which combines ultra high strength, high packing density and an improved ductility with a significantly increased energy dissipation capacity due to the addition of fiber reinforcement. With those attributes the material is potentially suitable for improved protective structural elements with a reduced need for material resources. The presented paper reports on an experimental series of scaled aircraft engine impact tests with reinforced UHPC panels. The investigations are focused on the material behavior and the damage intensity in comparison to conventional concrete. The fundamental work of is taken as reference for the evaluation of the results. The impactor model of a Phantom F4 GE-J79 engine developed and validated by Sugano et al. is used as defined in the original work. In order to achieve best comparability, the experimental configuration and method are adapted for the UHPC experiments. With 'penetration', 'scabbing' and 'perforation' all relevant damage modes defined in are investigated so that a full set of results are provided for a representative UHPC structural configuration.

  15. A Review of the Piezoelectric Electromechanical Impedance Based Structural Health Monitoring Technique for Engineering Structures

    Directory of Open Access Journals (Sweden)

    Wongi S. Na

    2018-04-01

    Full Text Available The birth of smart materials such as piezoelectric (PZT transducers has aided in revolutionizing the field of structural health monitoring (SHM based on non-destructive testing (NDT methods. While a relatively new NDT method known as the electromechanical (EMI technique has been investigated for more than two decades, there are still various problems that must be solved before it is applied to real structures. The technique, which has a significant potential to contribute to the creation of one of the most effective SHM systems, involves the use of a single PZT for exciting and sensing of the host structure. In this paper, studies applied for the past decade related to the EMI technique have been reviewed to understand its trend. In addition, new concepts and ideas proposed by various authors are also surveyed, and the paper concludes with a discussion of the potential directions for future works.

  16. Establishing Early Functional Perfusion and Structure in Tissue Engineered Cardiac Constructs

    Science.gov (United States)

    Wang, Bo; Patnaik, Sourav S.; Brazile, Bryn; Butler, J. Ryan; Claude, Andrew; Zhang, Ge; Guan, Jianjun; Hong, Yi; Liao, Jun

    2016-01-01

    Myocardial infarction (MI) causes massive heart muscle death and remains a leading cause of death in the world. Cardiac tissue engineering aims to replace the infarcted tissues with functional engineered heart muscles or revitalize the infarcted heart by delivering cells, bioactive factors, and/or biomaterials. One major challenge of cardiac tissue engineering and regeneration is the establishment of functional perfusion and structure to achieve timely angiogenesis and effective vascularization, which are essential to the survival of thick implants and the integration of repaired tissue with host heart. In this paper, we review four major approaches to promoting angiogenesis and vascularization in cardiac tissue engineering and regeneration: delivery of pro-angiogenic factors/molecules, direct cell implantation/cell sheet grafting, fabrication of prevascularized cardiac constructs, and the use of bioreactors to promote angiogenesis and vascularization. We further provide a detailed review and discussion on the early perfusion design in nature-derived biomaterials, synthetic biodegradable polymers, tissue-derived acellular scaffolds/whole hearts, and hydrogel derived from extracellular matrix. A better understanding of the current approaches and their advantages, limitations, and hurdles could be useful for developing better materials for future clinical applications. PMID:27480586

  17. A real-time all-atom structural search engine for proteins.

    Science.gov (United States)

    Gonzalez, Gabriel; Hannigan, Brett; DeGrado, William F

    2014-07-01

    Protein designers use a wide variety of software tools for de novo design, yet their repertoire still lacks a fast and interactive all-atom search engine. To solve this, we have built the Suns program: a real-time, atomic search engine integrated into the PyMOL molecular visualization system. Users build atomic-level structural search queries within PyMOL and receive a stream of search results aligned to their query within a few seconds. This instant feedback cycle enables a new "designability"-inspired approach to protein design where the designer searches for and interactively incorporates native-like fragments from proven protein structures. We demonstrate the use of Suns to interactively build protein motifs, tertiary interactions, and to identify scaffolds compatible with hot-spot residues. The official web site and installer are located at http://www.degradolab.org/suns/ and the source code is hosted at https://github.com/godotgildor/Suns (PyMOL plugin, BSD license), https://github.com/Gabriel439/suns-cmd (command line client, BSD license), and https://github.com/Gabriel439/suns-search (search engine server, GPLv2 license).

  18. TGP, an extremely stable, non-aggregating fluorescent protein created by structure-guided surface engineering

    Science.gov (United States)

    Close, Devin W.; Don Paul, Craig; Langan, Patricia S.; Wilce, Matthew C.J.; Traore, Daouda A.K.; Halfmann, Randal; Rocha, Reginaldo C.; Waldo, Geoffery S.; Payne, Riley J.; Rucker, Joseph B.; Prescott, Mark; Bradbury, Andrew R.M.

    2014-01-01

    In this paper we describe the engineering and X-ray crystal structure of Thermal Green Protein (TGP), an extremely stable, highly soluble, non-aggregating green fluorescent protein. TGP is a soluble variant of the fluorescent protein eCGP123, which despite being highly stable, has proven to be aggregation-prone. The X-ray crystal structure of eCGP123, also determined within the context of this paper, was used to carry out rational surface engineering to improve its solubility, leading to TGP. The approach involved simultaneously eliminating crystal lattice contacts while increasing the overall negative charge of the protein. Despite intentional disruption of lattice contacts and introduction of high entropy glutamate side chains, TGP crystallized readily in a number of different conditions and the X-ray crystal structure of TGP was determined to 1.9 Å resolution. The structural reasons for the enhanced stability of TGP and eCGP123 are discussed. We demonstrate the utility of using TGP as a fusion partner in various assays and significantly, in amyloid assays in which the standard fluorescent protein, EGFP, is undesirable because of aberrant oligomerization. PMID:25287913

  19. Thermal green protein, an extremely stable, nonaggregating fluorescent protein created by structure-guided surface engineering.

    Science.gov (United States)

    Close, Devin W; Paul, Craig Don; Langan, Patricia S; Wilce, Matthew C J; Traore, Daouda A K; Halfmann, Randal; Rocha, Reginaldo C; Waldo, Geoffery S; Payne, Riley J; Rucker, Joseph B; Prescott, Mark; Bradbury, Andrew R M

    2015-07-01

    In this article, we describe the engineering and X-ray crystal structure of Thermal Green Protein (TGP), an extremely stable, highly soluble, non-aggregating green fluorescent protein. TGP is a soluble variant of the fluorescent protein eCGP123, which despite being highly stable, has proven to be aggregation-prone. The X-ray crystal structure of eCGP123, also determined within the context of this paper, was used to carry out rational surface engineering to improve its solubility, leading to TGP. The approach involved simultaneously eliminating crystal lattice contacts while increasing the overall negative charge of the protein. Despite intentional disruption of lattice contacts and introduction of high entropy glutamate side chains, TGP crystallized readily in a number of different conditions and the X-ray crystal structure of TGP was determined to 1.9 Å resolution. The structural reasons for the enhanced stability of TGP and eCGP123 are discussed. We demonstrate the utility of using TGP as a fusion partner in various assays and significantly, in amyloid assays in which the standard fluorescent protein, EGFP, is undesirable because of aberrant oligomerization. © 2014 Wiley Periodicals, Inc.

  20. Form Follows Function: Advances in Trilayered Structure Replication for Aortic Heart Valve Tissue Engineering

    Science.gov (United States)

    Simionescu, Dan T.; Chen, Joseph; Jaeggli, Michael; Wang, Bo; Liao, Jun

    2013-01-01

    Tissue engineering the aortic heart valve is a challenging endeavor because of the particular hemodynamic and biologic conditions present in the native aortic heart valve. The backbone of an ideal valve substitute should be a scaffold that is strong enough to withstand billions of repetitive bending, flexing and stretching cycles, while also being slowly degradable to allow for remodeling. In this review we highlight three overlooked aspects that might influence the long term durability of tissue engineered valves: replication of the native valve trilayered histoarchitecture, duplication of the three-dimensional shape of the valve and cell integration efforts focused on getting the right number and type of cells to the right place within the valve structure and driving them towards homeostatic maintenance of the valve matrix. We propose that the trilayered structure in the native aortic valve that includes a middle spongiosa layer cushioning the motions of the two external fibrous layers should be our template for creation of novel scaffolds with improved mechanical durability. Furthermore, since cells adapt to micro-loads within the valve structure, we believe that interstitial cell remodeling of the valvular matrix will depend on the accurate replication of the structures and loads, resulting in successful regeneration of the valve tissue and extended durability. PMID:23355946

  1. Two-dimensional modeling of an aircraft engine structural bladed disk-casing modal interaction

    Science.gov (United States)

    Legrand, Mathias; Pierre, Christophe; Cartraud, Patrice; Lombard, Jean-Pierre

    2009-01-01

    In modern turbo machines such as aircraft jet engines, structural contacts between the casing and bladed disk may occur through a variety of mechanisms: coincidence of vibration modes, thermal deformation of the casing, rotor imbalance due to design uncertainties to name a few. These nonlinear interactions may result in severe damage to both structures and it is important to understand the physical circumstances under which they occur. In this study, we focus on a modal coincidence during which the vibrations of each structure take the form of a k-nodal diameter traveling wave characteristic of axi-symmetric geometries. A realistic two-dimensional model of the casing and bladed disk is introduced in order to predict the occurrence of this very specific interaction phenomenon versus the rotation speed of the engine. The equations of motion are solved using an explicit time integration scheme in conjunction with the Lagrange multiplier method where friction is accounted for. This model is validated from the comparison with an analytical solution. The numerical results show that the structures may experience different kinds of behaviors (namely damped, sustained and divergent motions) mainly depending on the rotational velocity of the bladed disk.

  2. Form Follows Function: Advances in Trilayered Structure Replication for Aortic Heart Valve Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Dan T. Simionescu

    2012-01-01

    Full Text Available Tissue engineering the aortic heart valve is a challenging endeavor because of the particular hemodynamic and biologic conditions present in the native aortic heart valve. The backbone of an ideal valve substitute should be a scaffold that is strong enough to withstand billions of repetitive bending, flexing and stretching cycles, while also being slowly degradable to allow for remodeling. In this review, we highlight three overlooked aspects that might influence the long term durability of tissue engineered valves: (i replication of the native valve trilayered histoarchitecture, (ii duplication of the three-dimensional shape of the valve, (iii and cell integration efforts focused on getting the right number and type of cells to the right place within the valve structure and driving them towards homeostatic maintenance of the valve matrix. We propose that the trilayered structure in the native aortic valve that includes a middle spongiosa layer cushioning the motions of the two external fibrous layers should be our template for creation of novel scaffolds with improved mechanical durability. Furthermore, since cells adapt to micro-loads within the valve structure, we believe that interstitial cell remodeling of the valvular matrix will depend on the accurate replication of the structures and loads, resulting in successful regeneration of the valve tissue and extended durability.

  3. Electronic structure engineering in silicene via atom substitution and a new two-dimensional Dirac structure Si3C

    Science.gov (United States)

    Yin, Na; Dai, Ying; Wei, Wei; Huang, Baibiao

    2018-04-01

    A lot of efforts have been made towards the band gap opening in two-dimensional silicene, the silicon version of graphene. In the present work, the electronic structures of single atom doped (B, N, Al and P) and codoped (B/N and Al/P) silicene monolayers are systematically examined on the base of density functional electronic calculations. Our results demonstrate that single atom doping can realize electron or hole doping in the silicene; while codoping, due to the syergistic effects, results in finite band gap in silicene at the Dirac point without significantly degrading the electronic properties. In addition, the characteristic of band gap shows dependence on the doping concentration. Importantly, we predict a new two-dimensional Dirac structure, the graphene-like Si3C, which also shows linear band dispersion relation around the Fermi level. Our results demonstrates an important perspective to engineer the electronic and optical properties of silicene.

  4. Fish assemblages at engineered and natural channel structures in the lower Missouri river: implications for modified dike structures

    Science.gov (United States)

    Schloesser, J.T.; Paukert, Craig P.; Doyle, W.J.; Hill, T.; Steffensen, K.D.; Travnichek, Vincent H.

    2012-01-01

    Large rivers throughout the world have been modified by using dike structures to divert water flows to deepwater habitats to maintain navigation channels. These modifications have been implicated in the decline in habitat diversity and native fishes. However, dike structures have been modified in the Missouri River USA to increase habitat diversity to aid in the recovery of native fishes. We compared species occupancy and fish community composition at natural sandbars and at notched and un-notched rock dikes along the lower Missouri River to determine if notching dikes increases species diversity or occupancy of native fishes. Fish were collected using gill nets, trammel nets, otter trawls, and mini fyke nets throughout the lower 1212 river km of the Missouri River USA from 2003 to 2006. Few differences in species richness and diversity were evident among engineered dike structures and natural sandbars. Notching a dike structure had no effect on proportional abundance of fluvial dependents, fluvial specialists, and macrohabitat generalists. Occupancy at notched dikes increased for two species but did not differ for 17 other species (81%). Our results suggest that dike structures may provide suitable habitats for fluvial species compared with channel sand bars, but dike notching did not increase abundance or occupancy of most Missouri River fishes. Published in 2011 by John Wiley & Sons, Ltd.

  5. Managing uncertainty in collaborative robotics engineering projects: The influence of task structure and peer interaction

    Science.gov (United States)

    Jordan, Michelle

    Uncertainty is ubiquitous in life, and learning is an activity particularly likely to be fraught with uncertainty. Previous research suggests that students and teachers struggle in their attempts to manage the psychological experience of uncertainty and that students often fail to experience uncertainty when uncertainty may be warranted. Yet, few educational researchers have explicitly and systematically observed what students do, their behaviors and strategies, as they attempt to manage the uncertainty they experience during academic tasks. In this study I investigated how students in one fifth grade class managed uncertainty they experienced while engaged in collaborative robotics engineering projects, focusing particularly on how uncertainty management was influenced by task structure and students' interactions with their peer collaborators. The study was initiated at the beginning of instruction related to robotics engineering and preceded through the completion of several long-term collaborative robotics projects, one of which was a design project. I relied primarily on naturalistic observation of group sessions, semi-structured interviews, and collection of artifacts. My data analysis was inductive and interpretive, using qualitative discourse analysis techniques and methods of grounded theory. Three theoretical frameworks influenced the conception and design of this study: community of practice, distributed cognition, and complex adaptive systems theory. Uncertainty was a pervasive experience for the students collaborating in this instructional context. Students experienced uncertainty related to the project activity and uncertainty related to the social system as they collaborated to fulfill the requirements of their robotics engineering projects. They managed their uncertainty through a diverse set of tactics for reducing, ignoring, maintaining, and increasing uncertainty. Students experienced uncertainty from more different sources and used more and

  6. Engineering the Surface/Interface Structures of Titanium Dioxide Micro and Nano Architectures towards Environmental and Electrochemical Applications

    DEFF Research Database (Denmark)

    Wang, Xiaoliang; Zhao, Yanyan; Mølhave, Kristian

    2017-01-01

    advances in the surface and interface engineering and applications in environmental and electrochemical applications. We analyze the advantages of surface/interface engineered TiO₂ micro and nano structures, and present the principles and growth mechanisms of TiO₂ nanostructures via different strategies...

  7. Improvement of Fatigue Life of Welded Structural Components of a Large Two-Stroke Diesel Engine by Grinding

    DEFF Research Database (Denmark)

    Agerskov, Henning; Hansen, Anders V.; Bjørnbak-Hansen, Jørgen

    2004-01-01

    The crankshaft housings of large two-stroke diesel engines are welded structures subjected to constant amplitude loading and designed for infinite life at full design load. A new design of the so-called frame box has been introduced in the engine using butt weld joints of thick plates, welded from...

  8. Operational modal analysis of civil engineering structures an introduction and guide for applications

    CERN Document Server

    Rainieri, Carlo

    2014-01-01

    This book covers all aspects of operational modal analysis for civil engineering, from theoretical background to applications, including measurement hardware, software development, and data processing. In particular, this book provides an extensive description and discussion of OMA methods, their classification and relationship, and advantages and drawbacks. The authors cover both the well-established theoretical background of OMA methods and the most recent developments in the field, providing detailed examples to help the reader better understand the concepts and potentialities of the technique. Additional material is provided (data, software) to help practitioners and students become familiar with OMA. Covering a range of different aspects of OMA, always with the application in mind, the practical perspective adopted in this book makes it ideal for a wide range of readers from researchers to field engineers; graduate and undergraduate students; and technicians interested in structural dynamics, system iden...

  9. Reverse engineering the structural and acoustic behavior of a stradivari violin

    Science.gov (United States)

    Pyrkosz, Michael

    There is a tremendous amount of mystery that surrounds the instruments of Antonio Stradivari. There have been many studies done in the past, but no one completely understands exactly how he made his instruments, or why they are still considered the best in the world. This project is designed to develop an engineering model of one of Stradivari's violins that will accurately simulate the structural and acoustic behavior of the instrument. It also hopes to shine some light on what makes the instruments of Stradivari unique when compared to other violins. It will focus on geometry and material properties, utilizing several modern engineering tools, including CT scanning, experimental modal analysis, finite element analysis, correlation techniques, and acoustic synthesis.

  10. Documentation for a Structural Optimization Procedure Developed Using the Engineering Analysis Language (EAL)

    Science.gov (United States)

    Martin, Carl J., Jr.

    1996-01-01

    This report describes a structural optimization procedure developed for use with the Engineering Analysis Language (EAL) finite element analysis system. The procedure is written primarily in the EAL command language. Three external processors which are written in FORTRAN generate equivalent stiffnesses and evaluate stress and local buckling constraints for the sections. Several built-up structural sections were coded into the design procedures. These structural sections were selected for use in aircraft design, but are suitable for other applications. Sensitivity calculations use the semi-analytic method, and an extensive effort has been made to increase the execution speed and reduce the storage requirements. There is also an approximate sensitivity update method included which can significantly reduce computational time. The optimization is performed by an implementation of the MINOS V5.4 linear programming routine in a sequential liner programming procedure.

  11. Graphite structural design code for the High Temperature Engineering Test Reactor

    International Nuclear Information System (INIS)

    1989-02-01

    The reactor internal structures of the High Temperature Engineering Test Reactor (HTTR) are made up of mainly graphite components. The characteristics of graphite are quite different in stress-strain behavior from metals, since the ductility of graphite is significantly less than metals. Therefore, the design codes provided for metal components can not be applied directly to graphite components. The graphite structural design code for the HTTR was drafted by JAERI and reviewed by specialists outside JAERI. The design code is established mainly on the basis of JAERI's research data and by reference to the fundamental concepts of the domestic design codes for metal components. In this design code, the graphite components are categorized into the core components and core support components and the stress limits are specified separately to meet the safety requirements to each. This report presents the graphite structural design code for the HTTR which is utlized for the present design of the HTTR. (author)

  12. 9th Saxonian radon day. 11th meeting on radon safe structural engineering; 9. Saechsischer Radontag. 11. Tagung radonsicheres Bauen

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-07-01

    The proceedings of the meeting in radon-safe structural engineering covers contributions on the following issues: implementation of the EU standards, radon protection in underground cavities, radon protection at working places, reports on experiences.

  13. Recent Progress in Engine Noise Reduction Technologies

    Science.gov (United States)

    Huff, Dennis; Gliebe, Philip

    2003-01-01

    Highlights from NASA-funded research over the past ten years for aircraft engine noise reduction are presented showing overall technical plans, accomplishments, and selected applications to turbofan engines. The work was sponsored by NASA's Advanced Subsonic Technology (AST) Noise Reduction Program. Emphasis is given to only the engine noise reduction research and significant accomplishments that were investigated at Technology Readiness Levels ranging from 4 to 6. The Engine Noise Reduction sub-element was divided into four work areas: source noise prediction, model scale tests, engine validation, and active noise control. Highlights from each area include technologies for higher bypass ratio turbofans, scarf inlets, forward-swept fans, swept and leaned stators, chevron/tabbed nozzles, advanced noise prediction analyses, and active noise control for fans. Finally, an industry perspective is given from General Electric Aircraft Engines showing how these technologies are being applied to commercial products. This publication contains only presentation vu-graphs from an invited lecture given at the 41st AIAA Aerospace Sciences Meeting, January 6-9, 2003.

  14. Geo synthetics in hydraulic and coastal engineering: Filters, revetments and sand filled structures

    International Nuclear Information System (INIS)

    Bezuijen, A.; Pilarczyk, K. W.

    2014-01-01

    The paper deals with 2 applications of geo textiles in coastal and hydraulic engineering: Geo textiles in filters and revetments; and geo textiles in sand filled structure. Geo textiles are often replacing granular filters. However, they have different properties than a granular filter. For the application of geo textiles in revetments, the consequences of the different properties will be shown: how permeability is influenced by a geo textile and what can be the consequences of the weight differences between granular and geo textile filters. In the other application, the filter properties of geo textiles are only secondary. In geo textile tubes and containers the geo textile is used as wrapping material to create large unties that will not erode during wave attach. the structures with geo textile tubes and containers serve as an alternative for rock based structures. The first of these structures were more or less constructed by trial and error, but research on the shape of the structures, the stability under wave attach and the durability of the used of the used material has given the possibility to use design tools for these structures. Recently also the morphological aspects of these structures have been investigated. This is of importance because regularly structures with geo textile tubes fail due to insufficient toe protection against the scour hole that that develops in front of the structure, leading to undermining of the structure. Recent research in the Dealt Flume of Deltares and the Large Wave Flume in Hannover has led to better understanding what mechanisms determine the stability under wave attach. It is shown that also the degree of filling is of importance and the position of the water level with respect to the tube has a large influence. (Author)

  15. Fish community structure in natural and engineered habitats in the Kansas River

    Science.gov (United States)

    White, K.; Gerken, J.; Paukert, Craig P.; Makinster, Andrew S.

    2010-01-01

    We investigated fish assemblage structure in engineered (rip-rap) and natural habitats (log jams and mud banks) in the Kansas River USA to determine if natural structures had higher abundance and diversity of fishes at a local spatial scale. A total of 439 randomly selected sites were boat electrofished from May to August 2005 and 2006. Mean species diversity and richness were significantly higher in rip-rap than log jams and mud banks. Mean relative abundance (CPUE; number of fish collected per hour electrofishing) of six of the 15 most common fishes (>1% of total catch) were most abundant in rip-rap, two were most abundant in log jams, and none in mud banks. Rip-rap had the highest relative abundance of fluvial specialist and macrohabitat generalists, whereas mean CPUE of fluvial dependents was highest in log jams. Although a discriminant function analysis indicated that nine size classes (eight species) discriminated among three habitat types, the high misclassification rate (38%) suggested a high degree of fish assemblage overlap among the habitats. Although previous work has suggested that engineered structures (rip-rap) and urbanization are linked to reduced biotic diversity or reduced growth of fish species, our results suggest that at a local scale rip-rap may not have the same negative impacts on fish assemblages.

  16. Erythropoietin modulates the structure of bone morphogenetic protein 2-engineered cranial bone.

    Science.gov (United States)

    Sun, Hongli; Jung, Younghun; Shiozawa, Yusuke; Taichman, Russell S; Krebsbach, Paul H

    2012-10-01

    The ideally engineered bone should have similar structural and functional properties to the native tissue. Although structural integrity is critical for functional bone regeneration, we know less about modulating the structural properties of the engineered bone elicited by bone morphogenetic protein (BMP) than efficacy and safety. Erythropoietin (Epo), a primary erythropoietic hormone, has been used to augment blood transfusion in orthopedic surgery. However, the effects of Epo on bone regeneration are not well known. Here, we determined the role of Epo in BMP2-induced bone regeneration using a cranial defect model. Epo administration improved the quality of BMP2-induced bone and more closely resembled natural cranial bone with a higher bone volume (BV) fraction and lower marrow fraction when compared with BMP2 treatment alone. Epo increased red blood cells (RBCs) in peripheral blood and also increased hematopoietic and mesenchymal stem cell (MSC) populations in bone marrow. Consistent with our previous work, Epo increased osteoclastogenesis both in vitro and in vivo. Results from a metatarsal organ culture assay suggested that Epo-promoted osteoclastogenesis contributed to angiogenesis because angiogenesis was blunted when osteoclastogenesis was blocked by alendronate (ALN) or osteoprotegerin (OPG). Earlier calcification of BMP2-induced temporary chondroid tissue was observed in the Epo+BMP group compared to BMP2 alone. We conclude that Epo significantly enhanced the outcomes of BMP2-induced cranial bone regeneration in part through its actions on osteoclastogenesis and angiogenesis.

  17. Flexible structure control experiments using a real-time workstation for computer-aided control engineering

    Science.gov (United States)

    Stieber, Michael E.

    1989-01-01

    A Real-Time Workstation for Computer-Aided Control Engineering has been developed jointly by the Communications Research Centre (CRC) and Ruhr-Universitaet Bochum (RUB), West Germany. The system is presently used for the development and experimental verification of control techniques for large space systems with significant structural flexibility. The Real-Time Workstation essentially is an implementation of RUB's extensive Computer-Aided Control Engineering package KEDDC on an INTEL micro-computer running under the RMS real-time operating system. The portable system supports system identification, analysis, control design and simulation, as well as the immediate implementation and test of control systems. The Real-Time Workstation is currently being used by CRC to study control/structure interaction on a ground-based structure called DAISY, whose design was inspired by a reflector antenna. DAISY emulates the dynamics of a large flexible spacecraft with the following characteristics: rigid body modes, many clustered vibration modes with low frequencies and extremely low damping. The Real-Time Workstation was found to be a very powerful tool for experimental studies, supporting control design and simulation, and conducting and evaluating tests withn one integrated environment.

  18. Improvement of Swirl Chamber Structure of Swirl-Chamber Diesel Engine Based on Flow Field Characteristics

    Directory of Open Access Journals (Sweden)

    Wenhua Yuan

    2014-10-01

    Full Text Available In order to improve combustion characteristic of swirl chamber diesel engine, a simulation model about a traditional cylindrical flat-bottom swirl chamber turbulent combustion diesel engine was established within the timeframe of the piston motion from the bottom dead centre (BDC to the top dead centre (TDC with the fluent dynamic mesh technique and flow field vector of gas in swirl chamber and cylinder; the pressure variation and temperature variation were obtained and a new type of swirl chamber structure was proposed. The results reveal that the piston will move from BDC; air in the cylinder is compressed into the swirl chamber by the piston to develop a swirl inside the chamber, with the ongoing of compression; the pressure and temperature are also rising gradually. Under this condition, the demand of diesel oil mixing and combusting will be better satisfied. Moreover, the new structure will no longer forma small fluid retention zone at the lower end outside the chamber and will be more beneficial to the mixing of fuel oil and air, which has presented a new idea and theoretical foundation for the design and optimization of swirl chamber structure and is thus of good significance of guiding in this regard.

  19. Structural Basis for the Altered PAM Recognition by Engineered CRISPR-Cpf1.

    Science.gov (United States)

    Nishimasu, Hiroshi; Yamano, Takashi; Gao, Linyi; Zhang, Feng; Ishitani, Ryuichiro; Nureki, Osamu

    2017-07-06

    The RNA-guided Cpf1 nuclease cleaves double-stranded DNA targets complementary to the CRISPR RNA (crRNA), and it has been harnessed for genome editing technologies. Recently, Acidaminococcus sp. BV3L6 (AsCpf1) was engineered to recognize altered DNA sequences as the protospacer adjacent motif (PAM), thereby expanding the target range of Cpf1-mediated genome editing. Whereas wild-type AsCpf1 recognizes the TTTV PAM, the RVR (S542R/K548V/N552R) and RR (S542R/K607R) variants can efficiently recognize the TATV and TYCV PAMs, respectively. However, their PAM recognition mechanisms remained unknown. Here we present the 2.0 Å resolution crystal structures of the RVR and RR variants bound to a crRNA and its target DNA. The structures revealed that the RVR and RR variants primarily recognize the PAM-complementary nucleotides via the substituted residues. Our high-resolution structures delineated the altered PAM recognition mechanisms of the AsCpf1 variants, providing a basis for the further engineering of CRISPR-Cpf1. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Developing a framework for qualitative engineering: Research in design and analysis of complex structural systems

    Science.gov (United States)

    Franck, Bruno M.

    1990-01-01

    The research is focused on automating the evaluation of complex structural systems, whether for the design of a new system or the analysis of an existing one, by developing new structural analysis techniques based on qualitative reasoning. The problem is to identify and better understand: (1) the requirements for the automation of design, and (2) the qualitative reasoning associated with the conceptual development of a complex system. The long-term objective is to develop an integrated design-risk assessment environment for the evaluation of complex structural systems. The scope of this short presentation is to describe the design and cognition components of the research. Design has received special attention in cognitive science because it is now identified as a problem solving activity that is different from other information processing tasks (1). Before an attempt can be made to automate design, a thorough understanding of the underlying design theory and methodology is needed, since the design process is, in many cases, multi-disciplinary, complex in size and motivation, and uses various reasoning processes involving different kinds of knowledge in ways which vary from one context to another. The objective is to unify all the various types of knowledge under one framework of cognition. This presentation focuses on the cognitive science framework that we are using to represent the knowledge aspects associated with the human mind's abstraction abilities and how we apply it to the engineering knowledge and engineering reasoning in design.

  1. SGO: A fast engine for ab initio atomic structure global optimization by differential evolution

    Science.gov (United States)

    Chen, Zhanghui; Jia, Weile; Jiang, Xiangwei; Li, Shu-Shen; Wang, Lin-Wang

    2017-10-01

    As the high throughout calculations and material genome approaches become more and more popular in material science, the search for optimal ways to predict atomic global minimum structure is a high research priority. This paper presents a fast method for global search of atomic structures at ab initio level. The structures global optimization (SGO) engine consists of a high-efficiency differential evolution algorithm, accelerated local relaxation methods and a plane-wave density functional theory code running on GPU machines. The purpose is to show what can be achieved by combining the superior algorithms at the different levels of the searching scheme. SGO can search the global-minimum configurations of crystals, two-dimensional materials and quantum clusters without prior symmetry restriction in a relatively short time (half or several hours for systems with less than 25 atoms), thus making such a task a routine calculation. Comparisons with other existing methods such as minima hopping and genetic algorithm are provided. One motivation of our study is to investigate the properties of magnetic systems in different phases. The SGO engine is capable of surveying the local minima surrounding the global minimum, which provides the information for the overall energy landscape of a given system. Using this capability we have found several new configurations for testing systems, explored their energy landscape, and demonstrated that the magnetic moment of metal clusters fluctuates strongly in different local minima.

  2. Strain engineering on structures and properties in ferroelectric thin films with perovskite structures

    Directory of Open Access Journals (Sweden)

    TANG Yanxue

    2015-08-01

    Full Text Available The class of Chaplygin gas models regarded as a candidate of dark energy can be realized by a scalar field,which could drive the variation of the fine structure constant α during the cosmic time.This phenomenon has been observed for almost ten years ago from the quasar absorption spectra and attracted many attentions.In this paper, the authors reconstruct the class of Chaplygin gas models to a kind of scalar fields and confront the resulting Δα/α with the observational constraints.It is found that if the present observational value of the equation of state of the dark energy was not exactly equal to -1, various parameters of the class of Chaplygin gas models are allowed to satisfy the observational constraints,as well as the equivalence principle is also respected.

  3. Pathway to oxide photovoltaics via band-structure engineering of SnO

    Directory of Open Access Journals (Sweden)

    Haowei Peng

    2016-10-01

    Full Text Available All-oxide photovoltaics could open rapidly scalable manufacturing routes, if only oxide materials with suitable electronic and optical properties were developed. SnO has exceptional doping and transport properties among oxides, but suffers from a strongly indirect band gap. Here, we address this shortcoming by band-structure engineering through isovalent but heterostructural alloying with divalent cations (Mg, Ca, Sr, and Zn. Using first-principles calculations, we show that suitable band gaps and optical properties close to that of direct semiconductors are achievable, while the comparatively small effective masses are preserved in the alloys. Initial thin film synthesis and characterization support the feasibility of the approach.

  4. Fabrication of scalable and structured tissue engineering scaffolds using water dissolvable sacrificial 3D printed moulds

    DEFF Research Database (Denmark)

    Mohanty, Soumyaranjan; Larsen, Layla Bashir; Trifol Guzman, Jon

    2015-01-01

    One of the major challenges in producing large scale engineered tissue is the lack of ability to create large highly perfused scaffolds in which cells can grow at a high cell density and viability. Here, we explore 3D printed polyvinyl alcohol (PVA) as a sacrificial mould in a polymer casting...... process. The PVA mould network defines the channels and is dissolved after curing the polymer casted around it. The printing parameters determined the PVA filament density in the sacrificial structure and this density resulted in different stiffness of the corresponding elastomer replica. It was possible...

  5. Pathway to oxide photovoltaics via band-structure engineering of SnO

    Science.gov (United States)

    Peng, Haowei; Bikowski, Andre; Zakutayev, Andriy; Lany, Stephan

    2016-10-01

    All-oxide photovoltaics could open rapidly scalable manufacturing routes, if only oxide materials with suitable electronic and optical properties were developed. SnO has exceptional doping and transport properties among oxides, but suffers from a strongly indirect band gap. Here, we address this shortcoming by band-structure engineering through isovalent but heterostructural alloying with divalent cations (Mg, Ca, Sr, and Zn). Using first-principles calculations, we show that suitable band gaps and optical properties close to that of direct semiconductors are achievable, while the comparatively small effective masses are preserved in the alloys. Initial thin film synthesis and characterization support the feasibility of the approach.

  6. An examination on aseismatic design of civil engineering structures in nuclear power stations

    International Nuclear Information System (INIS)

    Aida, Masakazu; Nakamura, Haruaki; Suzuki, Hideya

    1990-01-01

    As for the aseismatic design of civil engineering structures in nuclear power stations, the basic way of thinking and the example design are shown in the technical guidelines and others, but when the aseismatic design is actually carried out, the techniques of aseismatic calculation and the modeling for structural analysis are left to the judgement of designers. Among such various problems, in this report, the applicability of response displacement method and response magnitude method as the aseismatic calculation techniques and the necessity of rigid region in rahmen members in structural analysis were examined, and those are described. As the structures in nuclear power stations, there are cooling water intake and discharge facilities, emergency water intake, breakwater, unloading quays, revetments, the foundations of tanks, machinery and equipment, piping and others, roads, bridges, tunnels and so on. The outline of their aseismatic design and the examination on the cases of aseismatic design are reported. These structures are frequently underground structures, which are different from those on the ground. (K.I.)

  7. Mathematical and computational analyses of cracking formation fracture morphology and its evolution in engineering materials and structures

    CERN Document Server

    Sumi, Yoichi

    2014-01-01

    This book is about the pattern formation and the evolution of crack propagation in engineering materials and structures, bridging mathematical analyses of cracks based on singular integral equations, to computational simulation of engineering design. The first two parts of this book focus on elasticity and fracture and provide the basis for discussions on fracture morphology and its numerical simulation, which may lead to a simulation-based fracture control in engineering structures. Several design concepts are discussed for the prevention of fatigue and fracture in engineering structures, including safe-life design, fail-safe design, damage tolerant design. After starting with basic elasticity and fracture theories in parts one and two, this book focuses on the fracture morphology that develops due to the propagation of brittle cracks or fatigue cracks.   In part three, the mathematical analysis of a curved crack is precisely described, based on the perturbation method. The stability theory of interactive ...

  8. Implications for kinetochore-microtubule attachment from the structure of an engineered Ndc80 complex.

    Science.gov (United States)

    Ciferri, Claudio; Pasqualato, Sebastiano; Screpanti, Emanuela; Varetti, Gianluca; Santaguida, Stefano; Dos Reis, Gabriel; Maiolica, Alessio; Polka, Jessica; De Luca, Jennifer G; De Wulf, Peter; Salek, Mogjiborahman; Rappsilber, Juri; Moores, Carolyn A; Salmon, Edward D; Musacchio, Andrea

    2008-05-02

    Kinetochores are proteinaceous assemblies that mediate the interaction of chromosomes with the mitotic spindle. The 180 kDa Ndc80 complex is a direct point of contact between kinetochores and microtubules. Its four subunits contain coiled coils and form an elongated rod structure with functional globular domains at either end. We crystallized an engineered "bonsai" Ndc80 complex containing a shortened rod domain but retaining the globular domains required for kinetochore localization and microtubule binding. The structure reveals a microtubule-binding interface containing a pair of tightly interacting calponin-homology (CH) domains with a previously unknown arrangement. The interaction with microtubules is cooperative and predominantly electrostatic. It involves positive charges in the CH domains and in the N-terminal tail of the Ndc80 subunit and negative charges in tubulin C-terminal tails and is regulated by the Aurora B kinase. We discuss our results with reference to current models of kinetochore-microtubule attachment and centromere organization.

  9. Use of Time- and Frequency-Domain Approaches for Damage Detection in Civil Engineering Structures

    Directory of Open Access Journals (Sweden)

    V. H. Nguyen

    2014-01-01

    Full Text Available The aim of this paper is to apply both time- and frequency-domain-based approaches on real-life civil engineering structures and to assess their capability for damage detection. The methodology is based on Principal Component Analysis of the Hankel matrix built from output-only measurements and of Frequency Response Functions. Damage detection is performed using the concept of subspace angles between a current (possibly damaged state and a reference (undamaged state. The first structure is the Champangshiehl Bridge located in Luxembourg. Several damage levels were intentionally created by cutting a growing number of prestressed tendons and vibration data were acquired by the University of Luxembourg for each damaged state. The second example consists in reinforced and prestressed concrete panels. Successive damages were introduced in the panels by loading heavy weights and by cutting steel wires. The illustrations show different consequences in damage identification by the considered techniques.

  10. Exploring advantages of diverse carbon nanotube forests with tailored structures synthesized by supergrowth from engineered catalysts.

    Science.gov (United States)

    Zhao, Bin; Futaba, Don N; Yasuda, Satoshi; Akoshima, Megumi; Yamada, Takeo; Hata, Kenji

    2009-01-27

    We explored advantages of diverse carbon nanotube forests with tailored structures synthesized by water-assisted chemical vapor deposition (CVD) growth (supergrowth) from engineered catalysts. By controlling the catalyst film thickness, we synthesized carbon nanotube (CNT) forests composed from nanotubes with different size and wall number. With extensive characterizations, many interesting dependencies among CNT forest structures and their properties, which were unknown previously, were found. For example, multiwalled carbon nanotubes (MWNTs) showed superior electronic conductivity while single-walled carbon nanotubes (SWNTs) showed superior thermal diffusivity, and sparse MWNTs achieved lower threshold voltage for field emission than dense SWNTs. These interesting trends highlight the complexity in designing and choosing the optimum CNT forest for use in applications.

  11. Engineering the internal structure of magnetic silica nanoparticles by thermal control

    KAUST Repository

    Song, Hyon Min

    2014-09-30

    Calcination of hydrated iron salts in the pores of both spherical and rod-shaped mesoporous silica nanoparticles (NPs) changes the internal structure from an ordered 2D hexagonal structure into a smaller number of large voids in the particles with sizes ranging from large hollow cores down to ten nanometer voids. The voids only form when the heating rate is rapid at a rate of 30 °C min-1. The sizes of the voids are controlled reproducibly by the final calcination temperature; as the temperature is decreased the number of voids decreases as their size increases. The phase of the iron oxide NPs is α-Fe2O3 when annealed at 500 °C, and Fe3O4 when annealed at lower temperatures. The water molecules in the hydrated iron (III) chloride precursor salts appear to play important roles by hydrolyzing Si-O-Si bonding, and the resulting silanol is mobile enough to affect the reconstruction into the framed hollow structures at high temperature. Along with hexahydrates, trivalent Fe3+ ions are assumed to contribute to the structure disruption of mesoporous silica by replacing tetrahedral Si4+ ions and making Fe-O-Si bonding. Volume fraction tomography images generated from transmission electron microscopy (TEM) images enable precise visualization of the structures. These results provide a controllable method of engineering the internal shapes in silica matrices containing superparamagnetic NPs.

  12. Multi-energy radiography for non-destructive testing of materials and structures for civil engineering

    International Nuclear Information System (INIS)

    Naydenov, S.V.; Ryzhikov, V.

    2003-01-01

    Development of the technological base of modern non-destructive testing require new methods allowing determination of specified properties of materials and structures under study. A traditional direction of works is determination of internal spatial structure of the materials and other constructions. Restoration of this geometrical information is of qualitative character, though provides for determination of technical parameters affecting physical properties of the system. Reconstruction of the chemical composition, density and atomic structure (effective atomic number) is an inverse problem of direct quantitative determination of properties starting from data obtained by means of non-destructive testing. In the present work, we propose the use of multi-energy radiography for reconstruction of the substantial structure of materials. In framework of simple theoretical model it is shown that, using multi-channel absorption of X-rays, important substantial characteristics of materials and multi-compound structures can be readily reconstructed. The results obtained show high efficiency of 2-energy radiography for non-destructive testing in civil engineering

  13. Growth factor stimulation improves the structure and properties of scaffold-free engineered auricular cartilage constructs.

    Directory of Open Access Journals (Sweden)

    Renata G Rosa

    Full Text Available The reconstruction of the external ear to correct congenital deformities or repair following trauma remains a significant challenge in reconstructive surgery. Previously, we have developed a novel approach to create scaffold-free, tissue engineering elastic cartilage constructs directly from a small population of donor cells. Although the developed constructs appeared to adopt the structural appearance of native auricular cartilage, the constructs displayed limited expression and poor localization of elastin. In the present study, the effect of growth factor supplementation (insulin, IGF-1, or TGF-β1 was investigated to stimulate elastogenesis as well as to improve overall tissue formation. Using rabbit auricular chondrocytes, bioreactor-cultivated constructs supplemented with either insulin or IGF-1 displayed increased deposition of cartilaginous ECM, improved mechanical properties, and thicknesses comparable to native auricular cartilage after 4 weeks of growth. Similarly, growth factor supplementation resulted in increased expression and improved localization of elastin, primarily restricted within the cartilaginous region of the tissue construct. Additional studies were conducted to determine whether scaffold-free engineered auricular cartilage constructs could be developed in the 3D shape of the external ear. Isolated auricular chondrocytes were grown in rapid-prototyped tissue culture molds with additional insulin or IGF-1 supplementation during bioreactor cultivation. Using this approach, the developed tissue constructs were flexible and had a 3D shape in very good agreement to the culture mold (average error <400 µm. While scaffold-free, engineered auricular cartilage constructs can be created with both the appropriate tissue structure and 3D shape of the external ear, future studies will be aimed assessing potential changes in construct shape and properties after subcutaneous implantation.

  14. Engineering structure and thermal-technical analysis of fusion experimental breeder FEB divertor

    International Nuclear Information System (INIS)

    Feng Kaiming; Huang Jinhua; Zhu Yukun; Deng Peizhi; Zhou Xiaobing; Wang Min; Huo Tiejun

    1999-10-01

    On the basis of the physical study of FEB divertor, the engineering structure and thermal-technical analysis of FEB divertor are presented. In order to improve the impurity control and to increase ion-neutral interactions in the divertor, the configuration of the divertor is optimized to be the close type in the engineering design activity compared with the open type in the early conceptual activity. The operation mode of the divertor is designed to be partial detached plasma mode under conditions of combination gas-puffing with impurity injection. The position of gas-puffing is optimized at the torus mid-plane with NEWT1D code from the view point of impurity retention and radiation in the scrape-off layer/divertor region. The divertor structure is consisted of 48 rounded cassette modules. The thermal-technical calculations are carried out with COSMOS/M-HSTAR code for target plates. The result showed that the He-cooled target with 4 MPa coolant pressure and radial flowing is feasible

  15. Structural Basis for the Altered PAM Specificities of Engineered CRISPR-Cas9.

    Science.gov (United States)

    Hirano, Seiichi; Nishimasu, Hiroshi; Ishitani, Ryuichiro; Nureki, Osamu

    2016-03-17

    The RNA-guided endonuclease Cas9 cleaves double-stranded DNA targets bearing a PAM (protospacer adjacent motif) and complementarity to the guide RNA. A recent study showed that, whereas wild-type Streptococcus pyogenes Cas9 (SpCas9) recognizes the 5'-NGG-3' PAM, the engineered VQR, EQR, and VRER SpCas9 variants recognize the 5'-NGA-3', 5'-NGAG-3', and 5'-NGCG-3' PAMs, respectively, thus expanding the targetable sequences in Cas9-mediated genome editing applications. Here, we present the high-resolution crystal structures of the three SpCas9 variants in complexes with a single-guide RNA and its altered PAM-containing, partially double-stranded DNA targets. A structural comparison of the three SpCas9 variants with wild-type SpCas9 revealed that the multiple mutations synergistically induce an unexpected displacement in the phosphodiester backbone of the PAM duplex, thereby allowing the SpCas9 variants to directly recognize the altered PAM nucleotides. Our findings explain the altered PAM specificities of the SpCas9 variants and establish a framework for further rational engineering of CRISPR-Cas9. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Recent Advances in Organic Photovoltaics: Device Structure and Optical Engineering Optimization on the Nanoscale.

    Science.gov (United States)

    Luo, Guoping; Ren, Xingang; Zhang, Su; Wu, Hongbin; Choy, Wallace C H; He, Zhicai; Cao, Yong

    2016-03-23

    Organic photovoltaic (OPV) devices, which can directly convert absorbed sunlight to electricity, are stacked thin films of tens to hundreds of nanometers. They have emerged as a promising candidate for affordable, clean, and renewable energy. In the past few years, a rapid increase has been seen in the power conversion efficiency of OPV devices toward 10% and above, through comprehensive optimizations via novel photoactive donor and acceptor materials, control of thin-film morphology on the nanoscale, device structure developments, and interfacial and optical engineering. The intrinsic problems of short exciton diffusion length and low carrier mobility in organic semiconductors creates a challenge for OPV designs for achieving optically thick and electrically thin device structures to achieve sufficient light absorption and efficient electron/hole extraction. Recent advances in the field of OPV devices are reviewed, with a focus on the progress in device architecture and optical engineering approaches that lead to improved electrical and optical characteristics in OPV devices. Successful strategies are highlighted for light wave distribution, modulation, and absorption promotion inside the active layer of OPV devices by incorporating periodic nanopatterns/nanostructures or incorporating metallic nanomaterials and nanostructures. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Interface engineering in inorganic hybrid structures towards improved photocatalysis (Conference Presentation)

    Science.gov (United States)

    Xiong, Yujie

    2016-10-01

    Designing new photocatalytic materials for improving photoconversion efficiency is a promising route to alleviate the steadily worsening environmental issues and energy crisis. Despite the invention of a large number of catalytic materials with well-defined structures, their overall efficiency in photocatalysis is still quite limited as the three key steps - light harvesting, charge generation and separation, and charge transfer to surface for redox reactions - have not been substantially improved. To improve each step in the complex process, there is a major trend to develop materials based on inorganic hybrid structures. In this case, interface engineering holds the promise for boosting the overall efficiency, given the key roles of interface structures in charge and energy transfer. In this talk, I will demonstrate several different approaches to designing inorganic hybrid structures with improved photocatalytic performance via interface engineering. The typical demonstrations include semiconductor-plasmonics systems for broad-spectrum light harvesting, metal-semiconductor interfaces for improved charge separation, semiconductor-MOF (metal-organic framework) configurations for activated surface reactions. It is anticipated that this series of works open a new window to rationally designing inorganic hybrid materials for photo-induced applications. References: (1) Bai, S.; Yang, L.; Wang, C.; Lin, Y.; Lu, J.; Jiang, J. and Xiong, Y.*, Angew. Chem. Int. Ed. 54, 14810-14814 (2015). (2) Bai, S.; Jiang, J.; Zhang, Q. and Xiong, Y.*, Chem. Soc. Rev. 44, 2893-2939 (2015). (3) Bai, S.; Li, X.; Kong, Q.; Long, R.; Wang, C.; Jiang, J. and Xiong, Y.*, Adv. Mater. 27, 3444-3452 (2015). (4) Bai, S.; Ge, J.; Wang, L.; Gong, M.; Deng, M.; Kong, Q.; Song, L.; Jiang, J.;* Zhang, Q.;* Luo, Y.; Xie, Y. and Xiong, Y.*, Adv. Mater. 26, 5689-5695 (2014). (5) Li, R.; Hu, J.; Deng, M.; Wang, H.; Wang, X.; Hu, Y.; Jiang, H. L.; Jiang, J.;* Zhang, Q.;* Xie, Y. and Xiong, Y.*, Adv. Mater

  18. 78 FR 61168 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2013-10-03

    ... changes to the thermal profile and stresses in certain features of the low pressure turbine (LPT) Stage 2... Change the Costs of Compliance AAL requested that we change the costs of compliance to include the labor... will result in additional labor costs to access and replace those parts. We disagree. We consider the...

  19. 76 FR 2605 - Airworthiness Directives; Rolls-Royce plc RB211-Trent 800 Series Turbofan Engines

    Science.gov (United States)

    2011-01-14

    ... in increased fatigue life usage which is considered to have led to crack initiation and propagation... Web site, anyone can find and read the comments in any of our dockets, including, if provided, the... fatigue life usage which is considered to have led to crack initiation and propagation prior to reaching...

  20. 77 FR 6666 - Airworthiness Directives; CFM International, S.A. Turbofan Engines

    Science.gov (United States)

    2012-02-09

    ...; International Phone: 1-(513) 552-3272; USA Phone: (877) 432-3272; International Fax: 1-(513) 552-3329; USA Fax... that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in...

  1. 77 FR 60288 - Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines

    Science.gov (United States)

    2012-10-03

    ...: Distance from rear foot outer diameter surface to airfoil section along Planes S, SL, and SM. For Section B....149 mm) from rear foot outer diameter surface at Planes S, SL, and SM). At Section E-E (3.181 inches (80.797 mm) 1.314 inches (33.376 mm) minimum. from rear foot outer diameter surface at Planes S, SL...

  2. 78 FR 22180 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2013-04-15

    ... requires inspection of the intermediate pressure compressor rear stub shaft (IPC RSS) piston ring. This AD... found to be the piston ring seal, which fits in the groove of the Intermediate Pressure Compressor Rear... a piston ring seal that was not seated properly in the intermediate pressure compressor rear stub...

  3. 76 FR 67591 - Airworthiness Directives; Rolls-Royce Corporation Turbofan Engines

    Science.gov (United States)

    2011-11-02

    ... compressor wheels have chrome-carbide coated knife edge seals, use the compliance times listed in Table 2 of... knife edge seals, use the compliance times listed in Table 3 of this AD. (1) Perform a one-time... (ECI) of certain 6th-through-13th stage compressor wheel knife edge seals, and initial and repetitive...

  4. 78 FR 45842 - Airworthiness Directives; CFM International, S. A. Turbofan Engines

    Science.gov (United States)

    2013-07-30

    ..., call 781-238-7125. Examining the AD Docket You may examine the AD docket on the Internet at http://www... NPRM (78 FR 2644, January 14, 2013) and does not foresee being impacted by this AD now or in the future. Request To Include Minimum Threshold for TS-1 Fuel Usage Seven commenters requested that the NPRM (78 FR...

  5. 78 FR 37703 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2013-06-24

    ... subject of this AD. You may examine this AD on the Internet at http://ad.easa.europa.eu/ad/2013-0060 . (3... Docket You may examine the AD docket on the Internet at http://www.regulations.gov ; or in person at the...

  6. A Foreign Object Damage Event Detector Data Fusion System for Turbofan Engines

    National Research Council Canada - National Science Library

    Turso, James

    2004-01-01

    .... A fuzzy inference system provides basic probability assignments (bpa) based on features extracted from the gas path analysis and bearing accelerometers to a fusion algorithm based on the Dempster-Shafer-Yager Theory of Evidence...

  7. 75 FR 12663 - Airworthiness Directives; Honeywell International Inc. TFE731 Series Turbofan Engines

    Science.gov (United States)

    2010-03-17

    ... Paramount Blvd., Lakewood, CA 90712-4137; e-mail: [email protected] ; telephone: (562) 627-5246; fax....125 Series 1A, 3A, and 3A/ British Aerospace and Hawker RA, HS.125 Series F3B and F3B/ Beechcraft Corporation). RA, BH.125 and DH.125 Series 400A, HS.125 Series 403B, F400B, and F403B, HS.125 Series 600A, BH...

  8. 78 FR 5 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2013-01-02

    ... will be magnetized as part of the Superconductive Quantitative Inductive Device (SQUID) inspection... Superconductive Quantitative Inductive Device (SQUID) inspection of the disc at the next shop visit or before the... A, Subpart III, Section 44701: General requirements.'' Under that section, Congress charges the FAA...

  9. 77 FR 40820 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Science.gov (United States)

    2012-07-11

    ... requirements.'' Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in... perform a Superconductive Quantitative Inductive Device (SQUID) inspection of the disc at the next shop...

  10. Engineering characterization of ground motion. Task II. Effects of ground motion characteristics on structural response considering localized structural nonlinearities and soil-structure interaction effects. Volume 2

    International Nuclear Information System (INIS)

    Kennedy, R.P.; Kincaid, R.H.; Short, S.A.

    1985-03-01

    This report presents the results of part of a two-task study on the engineering characterization of earthquake ground motion for nuclear power plant design. Task I of the study, which is presented in NUREG/CR-3805, Vol. 1, developed a basis for selecting design response spectra taking into account the characteristics of free-field ground motion found to be significant in causing structural damage. Task II incorporates additional considerations of effects of spatial variations of ground motions and soil-structure interaction on foundation motions and structural response. The results of Task II are presented in four parts: (1) effects of ground motion characteristics on structural response of a typical PWR reactor building with localized nonlinearities and soil-structure interaction effects; (2) empirical data on spatial variations of earthquake ground motion; (3) soil-structure interaction effects on structural response; and (4) summary of conclusions and recommendations based on Tasks I and II studies. This report presents the results of the first part of Task II. The results of the other parts will be presented in NUREG/CR-3805, Vols. 3 to 5

  11. Engineering tissue constructs to mimic native aortic and pulmonary valve leaflets' structures and mechanics

    Science.gov (United States)

    Masoumi, Nafiseh

    There are several disadvantages correlated with current heart valve replacement, including anticoagulation therapy for patients with mechanical valves and the low durability of bioprosthetic valves. The non-viable nature of such devices is a critical drawback especially for pediatric cases due to the inability of the graft to grow in vivo with the patients. A tissue engineered heart valve (TEHV) with remodeling and growth ability, is conceptually appealing to use in the surgical repair and could serve as a permanent replacements when operating for pediatric valvular lesions. It is critical that scaffolds for functional heart valve tissue engineering, be capable of mimicking the native leaflet's structure and mechanical properties at the time of implantation. Meanwhile, the scaffolds should be able to support cellular proliferation and native-like tissue formation as the TEHV remodels toward a scaffold-free state. Our overall hypothesis is that an "ideal" engineered construct, designed based on native leaflet's structure and mechanics, will complement a native heart valve leaflet in providing benchmarks for use in the design of clinically-applicable TEHV. This hypothesis was addressed through several experiments conducted in the present study. To establish a functional biomimetic TEHV, we developed scaffolds capable of matching the anisotropic stiffness of native leaflet while promoting native-like cell and collagen content and supporting the ECM generation. Scaffolds with various polymer contents (e.g., poly (glycerol sebacate) (PGS) and poly (epsilon-caprolactone) (PCL)) and structural designs (e.g., microfabricated and microfibrous scaffolds), were fabricated based on native leaflet's structure and mechanics. It was found that the tri-layered scaffold, designed with assembly of microfabricated PGS and microfibrous PGS/PCL was a functional leaflet capable of promoting tissue formation. Furthermore, to investigate the effect of cyclic stress and flexure

  12. Structure-oriented substrate specificity engineering of aldehyde-deformylating oxygenase towards aldehydes carbon chain length.

    Science.gov (United States)

    Bao, Luyao; Li, Jian-Jun; Jia, Chenjun; Li, Mei; Lu, Xuefeng

    2016-01-01

    Aldehyde-deformylating oxygenase (ADO) is an important enzyme involved in the biosynthetic pathway of fatty alk(a/e)nes in cyanobacteria. However, ADO exhibits quite low chain-length specificity with respect to the substrates ranging from C4 to C18 aldehydes, which is not suitable for producing fuels with different properties or different chain lengths. Based on the crystal structures of cADOs (cyanobacterial ADO) with substrate analogs bound, some amino acids affecting the substrate specificity of cADO were identified, including the amino acids close to the aldehyde group and the hydrophobic tail of the substrate and those along the substrate channel. Using site-directed mutagenesis, selected amino acids were replaced with bulky ones introducing steric hindrance to the binding pocket via large functional groups. All mutants were overexpressed, purified and kinetically characterized. All mutants, except F87Y, displayed dramatically reduced activity towards C14,16,18 aldehydes. Notably, the substrate preferences of some mutants towards different chain-length substrates were enhanced: I24Y for n-heptanal, I27F for n-decanal and n-dodecanal, V28F for n-dodecanal, F87Y for n-decanal, C70F for n-hexanal, A118F for n-butanal, A121F for C4,6,7 aldehydes, V184F for n-dodecanal and n-decanal, M193Y for C6-10 aldehydes and L198F for C7-10 aldehydes. The impact of the engineered cADO mutants on the change of the hydrocarbon profile was demonstrated by co-expressing acyl-ACP thioesterase BTE, fadD and V184F in E. coli, showing that n-undecane was the main fatty alkane. Some amino acids, which can control the chain-length selectivity of substrates of cADO, were identified. The substrate specificities of cADO were successfully changed through structure-guided protein engineering, and some mutants displayed different chain-length preference. The in vivo experiments of V184F in genetically engineered E. coli proved the importance of engineered cADOs on the distribution of the

  13. Reverse engineering of wörner type drilling machine structure.

    Science.gov (United States)

    Wibowo, A.; Belly, I.; llhamsyah, R.; Indrawanto; Yuwana, Y.

    2018-03-01

    A product design needs to be modified based on the conditions of production facilities and existing resource capabilities without reducing the functional aspects of the product itself. This paper describes the reverse engineering process of the main structure of the wörner type drilling machine to obtain a machine structure design that can be made by resources with limited ability by using simple processes. Some structural, functional and the work mechanism analyzes have been performed to understand the function and role of each basic components. The process of dismantling of the drilling machine and measuring each of the basic components was performed to obtain sets of the geometry and size data of each component. The geometric model of each structure components and the machine assembly were built to facilitate the simulation process and machine performance analysis that refers to ISO standard of drilling machine. The tolerance stackup analysis also performed to determine the type and value of geometrical and dimensional tolerances, which could affect the ease of the components to be manufactured and assembled

  14. A refined Frequency Domain Decomposition tool for structural modal monitoring in earthquake engineering

    Science.gov (United States)

    Pioldi, Fabio; Rizzi, Egidio

    2017-07-01

    Output-only structural identification is developed by a refined Frequency Domain Decomposition ( rFDD) approach, towards assessing current modal properties of heavy-damped buildings (in terms of identification challenge), under strong ground motions. Structural responses from earthquake excitations are taken as input signals for the identification algorithm. A new dedicated computational procedure, based on coupled Chebyshev Type II bandpass filters, is outlined for the effective estimation of natural frequencies, mode shapes and modal damping ratios. The identification technique is also coupled with a Gabor Wavelet Transform, resulting in an effective and self-contained time-frequency analysis framework. Simulated response signals generated by shear-type frames (with variable structural features) are used as a necessary validation condition. In this context use is made of a complete set of seismic records taken from the FEMA P695 database, i.e. all 44 "Far-Field" (22 NS, 22 WE) earthquake signals. The modal estimates are statistically compared to their target values, proving the accuracy of the developed algorithm in providing prompt and accurate estimates of all current strong ground motion modal parameters. At this stage, such analysis tool may be employed for convenient application in the realm of Earthquake Engineering, towards potential Structural Health Monitoring and damage detection purposes.

  15. Structure-guided sequence specificity engineering of the modification-dependent restriction endonuclease LpnPI.

    Science.gov (United States)

    Sasnauskas, Giedrius; Zagorskaitė, Evelina; Kauneckaitė, Kotryna; Tamulaitiene, Giedre; Siksnys, Virginijus

    2015-07-13

    The eukaryotic Set and Ring Associated (SRA) domains and structurally similar DNA recognition domains of prokaryotic cytosine modification-dependent restriction endonucleases recognize methylated, hydroxymethylated or glucosylated cytosine in various sequence contexts. Here, we report the apo-structure of the N-terminal SRA-like domain of the cytosine modification-dependent restriction enzyme LpnPI that recognizes modified cytosine in the 5'-C(mC)DG-3' target sequence (where mC is 5-methylcytosine or 5-hydroxymethylcytosine and D = A/T/G). Structure-guided mutational analysis revealed LpnPI residues involved in base-specific interactions and demonstrated binding site plasticity that allowed limited target sequence degeneracy. Furthermore, modular exchange of the LpnPI specificity loops by structural equivalents of related enzymes AspBHI and SgrTI altered sequence specificity of LpnPI. Taken together, our results pave the way for specificity engineering of the cytosine modification-dependent restriction enzymes. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  16. Application of Composite Structures in Bridge Engineering. Problems of Construction Process and Strength Analysis

    Science.gov (United States)

    Flaga, Kazimierz; Furtak, Kazimierz

    2015-03-01

    Steel-concrete composite structures have been used in bridge engineering from decades. This is due to rational utilisation of the strength properties of the two materials. At the same time, the reinforced concrete (or prestressed) deck slab is more favourable than the orthotropic steel plate used in steel bridges (higher mass, better vibration damping, longer life). The most commonly found in practice are composite girder bridges, particularly in highway bridges of small and medium spans, but the spans may reach over 200 m. In larger spans steel truss girders are applied. Bridge composite structures are also employed in cable-stayed bridge decks of the main girder spans of the order of 600, 800 m. The aim of the article is to present the cionstruction process and strength analysis problems concerning of this type of structures. Much attention is paid to the design and calculation of the shear connectors characteristic for the discussed objects. The authors focused mainly on the issues of single composite structures. The effect of assembly states on the stresses and strains in composite members are highlighted. A separate part of problems is devoted to the influence of rheological factors, i.e. concrete shrinkage and creep, as well as thermal factors on the stresses and strains and redistribution of internal forces.

  17. Applications of Artificial Neural Networks in Structural Engineering with Emphasis on Continuum Models

    Science.gov (United States)

    Kapania, Rakesh K.; Liu, Youhua

    1998-01-01

    The use of continuum models for the analysis of discrete built-up complex aerospace structures is an attractive idea especially at the conceptual and preliminary design stages. But the diversity of available continuum models and hard-to-use qualities of these models have prevented them from finding wide applications. In this regard, Artificial Neural Networks (ANN or NN) may have a great potential as these networks are universal approximators that can realize any continuous mapping, and can provide general mechanisms for building models from data whose input-output relationship can be highly nonlinear. The ultimate aim of the present work is to be able to build high fidelity continuum models for complex aerospace structures using the ANN. As a first step, the concepts and features of ANN are familiarized through the MATLAB NN Toolbox by simulating some representative mapping examples, including some problems in structural engineering. Then some further aspects and lessons learned about the NN training are discussed, including the performances of Feed-Forward and Radial Basis Function NN when dealing with noise-polluted data and the technique of cross-validation. Finally, as an example of using NN in continuum models, a lattice structure with repeating cells is represented by a continuum beam whose properties are provided by neural networks.

  18. Optimization of Turbine Engine Cycle Analysis with Analytic Derivatives

    Science.gov (United States)

    Hearn, Tristan; Hendricks, Eric; Chin, Jeffrey; Gray, Justin; Moore, Kenneth T.

    2016-01-01

    A new engine cycle analysis tool, called Pycycle, was recently built using the OpenMDAO framework. This tool uses equilibrium chemistry based thermodynamics, and provides analytic derivatives. This allows for stable and efficient use of gradient-based optimization and sensitivity analysis methods on engine cycle models, without requiring the use of finite difference derivative approximation methods. To demonstrate this, a gradient-based design optimization was performed on a multi-point turbofan engine model. Results demonstrate very favorable performance compared to an optimization of an identical model using finite-difference approximated derivatives.

  19. Towards high performance computing for molecular structure prediction using IBM Cell Broadband Engine - an implementation perspective

    Science.gov (United States)

    2010-01-01

    Background RNA structure prediction problem is a computationally complex task, especially with pseudo-knots. The problem is well-studied in existing literature and predominantly uses highly coupled Dynamic Programming (DP) solutions. The problem scale and complexity become embarrassingly humungous to handle as sequence size increases. This makes the case for parallelization. Parallelization can be achieved by way of networked platforms (clusters, grids, etc) as well as using modern day multi-core chips. Methods In this paper, we exploit the parallelism capabilities of the IBM Cell Broadband Engine to parallelize an existing Dynamic Programming (DP) algorithm for RNA secondary structure prediction. We design three different implementation strategies that exploit the inherent data, code and/or hybrid parallelism, referred to as C-Par, D-Par and H-Par, and analyze their performances. Our approach attempts to introduce parallelism in critical sections of the algorithm. We ran our experiments on SONY Play Station 3 (PS3), which is based on the IBM Cell chip. Results Our results suggest that introducing parallelism in DP algorithm allows it to easily handle longer sequences which otherwise would consume a large amount of time in single core computers. The results further demonstrate the speed-up gain achieved in exploiting the inherent parallelism in the problem and also elicits the advantages of using multi-core platforms towards designing more sophisticated methodologies for handling a fairly long sequence of RNA. Conclusion The speed-up performance reported here is promising, especially when sequence length is long. To the best of our literature survey, the work reported in this paper is probably the first-of-its-kind to utilize the IBM Cell Broadband Engine (a heterogeneous multi-core chip) to implement a DP. The results also encourage using multi-core platforms towards designing more sophisticated methodologies for handling a fairly long sequence of RNA to predict

  20. Jet Engine Noise Generation, Prediction and Control. Chapter 86

    Science.gov (United States)

    Huff, Dennis L.; Envia, Edmane

    2004-01-01

    Aircraft noise has been a problem near airports for many years. It is a quality of life issue that impacts millions of people around the world. Solving this problem has been the principal goal of noise reduction research that began when commercial jet travel became a reality. While progress has been made in reducing both airframe and engine noise, historically, most of the aircraft noise reduction efforts have concentrated on the engines. This was most evident during the 1950 s and 1960 s when turbojet engines were in wide use. This type of engine produces high velocity hot exhaust jets during takeoff generating a great deal of noise. While there are fewer commercial aircraft flying today with turbojet engines, supersonic aircraft including high performance military aircraft use engines with similar exhaust flow characteristics. The Pratt & Whitney F100-PW-229, pictured in Figure la, is an example of an engine that powers the F-15 and F-16 fighter jets. The turbofan engine was developed for subsonic transports, which in addition to better fuel efficiency also helped mitigate engine noise by reducing the jet exhaust velocity. These engines were introduced in the late 1960 s and power most of the commercial fleet today. Over the years, the bypass ratio (that is the ratio of the mass flow through the fan bypass duct to the mass flow through the engine core) has increased to values approaching 9 for modern turbofans such as the General Electric s GE-90 engine (Figure lb). The benefits to noise reduction for high bypass ratio (HPBR) engines are derived from lowering the core jet velocity and temperature, and lowering the tip speed and pressure ratio of the fan, both of which are the consequences of the increase in bypass ratio. The HBPR engines are typically very large in diameter and can produce over 100,000 pounds of thrust for the largest engines. A third type of engine flying today is the turbo-shaft which is mainly used to power turboprop aircraft and helicopters

  1. Computational Fluid Dynamics Modeling of a Supersonic Nozzle and Integration into a Variable Cycle Engine Model

    Science.gov (United States)

    Connolly, Joseph W.; Friedlander, David; Kopasakis, George

    2015-01-01

    This paper covers the development of an integrated nonlinear dynamic simulation for a variable cycle turbofan engine and nozzle that can be integrated with an overall vehicle Aero-Propulso-Servo-Elastic (APSE) model. A previously developed variable cycle turbofan engine model is used for this study and is enhanced here to include variable guide vanes allowing for operation across the supersonic flight regime. The primary focus of this study is to improve the fidelity of the model's thrust response by replacing the simple choked flow equation convergent-divergent nozzle model with a MacCormack method based quasi-1D model. The dynamic response of the nozzle model using the MacCormack method is verified by comparing it against a model of the nozzle using the conservation element/solution element method. A methodology is also presented for the integration of the MacCormack nozzle model with the variable cycle engine.

  2. Full Scale Technology Demonstration of a Modern Counterrotating Unducted Fan Engine Concept. Design Report

    Science.gov (United States)

    1987-01-01

    The Unducted Fan engine (UDF trademark) concept is based on an ungeared, counterrotating, unducted, ultra-high-bypass turbofan configuration. This engine is being developed to provide a high thrust-to-weight ratio power plant with exceptional fuel efficiency for subsonic aircraft application. This report covers the design methodology and details for the major components of this engine. The design intent of the engine is to efficiently produce 25,000 pounds of static thrust while meeting life and stress requirements. The engine is required to operate at Mach numbers of 0.8 or above.

  3. Intelligent Mining Engineering Systems in the Structure of Industry 4.0

    Directory of Open Access Journals (Sweden)

    Rylnikova Marina

    2017-01-01

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

  4. Intelligent Mining Engineering Systems in the Structure of Industry 4.0

    Science.gov (United States)

    Rylnikova, Marina; Radchenko, Dmitriy; Klebanov, Dmitriy

    2017-11-01

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

  5. Biomimetic self-templating optical structures fabricated by genetically engineered M13 bacteriophage.

    Science.gov (United States)

    Kim, Won-Geun; Song, Hyerin; Kim, Chuntae; Moon, Jong-Sik; Kim, Kyujung; Lee, Seung-Wuk; Oh, Jin-Woo

    2016-11-15

    Here, we describe a highly sensitive and selective surface plasmon resonance sensor system by utilizing self-assembly of genetically engineered M13 bacteriophage. About 2700 copies of genetically expressed peptide copies give superior selectivity and sensitivity to M13 phage-based SPR sensor. Furthermore, the sensitivity of the M13 phage-based SPR sensor was enhanced due to the aligning of receptor matrix in specific direction. Incorporation of specific binding peptide (His Pro Gln: HPQ) gives M13 bacteriophage high selectivity for the streptavidin. Our M13 phage-based SPR sensor takes advantage of simplicity of self-assembly compared with relatively complex photolithography techniques or chemical conjugations. Additionally, designed structure which is composed of functionalized M13 bacteriophage can simultaneously improve the sensitivity and selectivity of SPR sensor evidently. By taking advantages of the genetic engineering and self-assembly, we propose the simple method for fabricating novel M13 phage-based SPR sensor system which has a high sensitivity and high selectivity. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. ChemEngine: harvesting 3D chemical structures of supplementary data from PDF files.

    Science.gov (United States)

    Karthikeyan, Muthukumarasamy; Vyas, Renu

    2016-01-01

    Digital access to chemical journals resulted in a vast array of molecular information that is now available in the supplementary material files in PDF format. However, extracting this molecular information, generally from a PDF document format is a daunting task. Here we present an approach to harvest 3D molecular data from the supporting information of scientific research articles that are normally available from publisher's resources. In order to demonstrate the feasibility of extracting truly computable molecules from PDF file formats in a fast and efficient manner, we have developed a Java based application, namely ChemEngine. This program recognizes textual patterns from the supplementary data and generates standard molecular structure data (bond matrix, atomic coordinates) that can be subjected to a multitude of computational processes automatically. The methodology has been demonstrated via several case studies on different formats of coordinates data stored in supplementary information files, wherein ChemEngine selectively harvested the atomic coordinates and interpreted them as molecules with high accuracy. The reusability of extracted molecular coordinate data was demonstrated by computing Single Point Energies that were in close agreement with the original computed data provided with the articles. It is envisaged that the methodology will enable large scale conversion of molecular information from supplementary files available in the PDF format into a collection of ready- to- compute molecular data to create an automated workflow for advanced computational processes. Software along with source codes and instructions available at https://sourceforge.net/projects/chemengine/files/?source=navbar.Graphical abstract.

  7. A structured approach for the engineering of biochemical network models, illustrated for signalling pathways.

    Science.gov (United States)

    Breitling, Rainer; Gilbert, David; Heiner, Monika; Orton, Richard

    2008-09-01

    Quantitative models of biochemical networks (signal transduction cascades, metabolic pathways, gene regulatory circuits) are a central component of modern systems biology. Building and managing these complex models is a major challenge that can benefit from the application of formal methods adopted from theoretical computing science. Here we provide a general introduction to the field of formal modelling, which emphasizes the intuitive biochemical basis of the modelling process, but is also accessible for an audience with a background in computing science and/or model engineering. We show how signal transduction cascades can be modelled in a modular fashion, using both a qualitative approach--qualitative Petri nets, and quantitative approaches--continuous Petri nets and ordinary differential equations (ODEs). We review the major elementary building blocks of a cellular signalling model, discuss which critical design decisions have to be made during model building, and present a number of novel computational tools that can help to explore alternative modular models in an easy and intuitive manner. These tools, which are based on Petri net theory, offer convenient ways of composing hierarchical ODE models, and permit a qualitative analysis of their behaviour. We illustrate the central concepts using signal transduction as our main example. The ultimate aim is to introduce a general approach that provides the foundations for a structured formal engineering of large-scale models of biochemical networks.

  8. Techniques to assess acoustic-structure interaction in liquid rocket engines

    Science.gov (United States)

    Davis, R. Benjamin

    Acoustoelasticity is the study of the dynamic interaction between elastic structures and acoustic enclosures. In this dissertation, acoustoelasticity is considered in the context of liquid rocket engine design. The techniques presented here can be used to determine which forcing frequencies are important in acoustoelastic systems. With a knowledge of these frequencies, an analyst can either find ways to attenuate the excitation at these frequencies or alter the system in such a way that the prescribed excitations do result in a resonant condition. The end result is a structural component that is less susceptible to failure. The research scope is divided into three parts. In the first part, the dynamics of cylindrical shells submerged in liquid hydrogen (LH2) and liquid oxygen (LOX) are considered. The shells are bounded by rigid outer cylinders. This configuration gives rise to two fluid-filled cavities---an inner cylindrical cavity and an outer annular cavity. Such geometries are common in rocket engine design. The natural frequencies and modes of the fluid-structure system are computed by combining the rigid wall acoustic cavity modes and the in vacuo structural modes into a system of coupled ordinary differential equations. Eigenvalue veering is observed near the intersections of the curves representing natural frequencies of the rigid wall acoustic and the in vacuo structural modes. In the case of a shell submerged in LH2, system frequencies near these intersections are as much as 30% lower than the corresponding in vacuo structural frequencies. Due to its high density, the frequency reductions in the presence of LOX are even more dramatic. The forced responses of a shell submerged in LH2 and LOX while subject to a harmonic point excitation are also presented. The responses in the presence of fluid are found to be quite distinct from those of the structure in vacuo. In the second part, coupled mode theory is used to explore the fundamental features of

  9. Study on monitoring of deep foundation pit with SMW engineering method plus anchor cable retaining structure

    Science.gov (United States)

    Chen, Wenzhao; Cui, Wenping

    2018-03-01

    The SMW method has many advantages, such as little influence on the surrounding environment, good watertight performance, wide range of application, short construction period, low cost and so on. In this paper, we chose the SMW engineering method combined with anchor cable to support structure in the second phase deep foundation pit of Jinan LuJinDongCheng as the research object, monitored and analysed the horizontal displacement of the pile top, Peripheral surface subsidence and internal force of the anchor cable in the foundation pit. We also discussed the displacement, internal force of anchor cable and the settlement of surrounding environment in the excavation of foundation pit and in different stages of construction. Conclusion:(1)The maximum horizontal displacement of the retaining structure is closely related to the depth and time of excavation, the construction of anchor cable can well limit the deformation of pile body; (2)Groundwater seepage caused by foundation pit dewatering will change the effective stress of soil. The change of groundwater level has an important influence on the working behavior of smw anchor cable supporting structure.

  10. Valley and band structure engineering of folded MoS(2) bilayers.

    Science.gov (United States)

    Jiang, Tao; Liu, Hengrui; Huang, Di; Zhang, Shuai; Li, Yingguo; Gong, Xingao; Shen, Yuen-Ron; Liu, Wei-Tao; Wu, Shiwei

    2014-10-01

    Artificial structures made of stacked two-dimensional crystals have recently been the focus of intense research activity. As in twisted or stacked graphene layers, these structures can show unusual behaviours and new phenomena. Among the various layered compounds that can be exfoliated, transition-metal dichalcogenides exhibit interesting properties governed by their structural symmetry and interlayer coupling, which are highly susceptible to stacking. Here, we obtain-by folding exfoliated MoS2 monolayers-MoS2 bilayers with different stacking orders, as monitored by second harmonic generation and photoluminescence. Appropriate folding can break the inversion symmetry and suppress interlayer hopping, evoking strong valley and spin polarizations that are not achieved in natural MoS2 bilayers of Bernal stacking. It can also enlarge the indirect bandgap by more than 100 meV through a decrease in the interlayer coupling. Our work provides an effective and versatile means to engineer transition-metal dichalcogenide materials with desirable electronic and optical properties.

  11. Structural Plasticity of PAM Recognition by Engineered Variants of the RNA-Guided Endonuclease Cas9.

    Science.gov (United States)

    Anders, Carolin; Bargsten, Katja; Jinek, Martin

    2016-03-17

    The RNA-guided endonuclease Cas9 from Streptococcus pyogenes (SpCas9) forms the core of a powerful genome editing technology. DNA cleavage by SpCas9 is dependent on the presence of a 5'-NGG-3' protospacer adjacent motif (PAM) in the target DNA, restricting the choice of targetable sequences. To address this limitation, artificial SpCas9 variants with altered PAM specificities have recently been developed. Here we report crystal structures of the VQR, EQR, and VRER SpCas9 variants bound to target DNAs containing their preferred PAM sequences. The structures reveal that the non-canonical PAMs are recognized by an induced fit mechanism. Besides mediating sequence-specific base recognition, the amino acid substitutions introduced in the SpCas9 variants facilitate conformational remodeling of the PAM region of the bound DNA. Guided by the structural data, we engineered a SpCas9 variant that specifically recognizes NAAG PAMs. Taken together, these studies inform further development of Cas9-based genome editing tools. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. An interferometric radar for displacement measurement and its application in civil engineering structures

    Science.gov (United States)

    Su, D.; Nagayama, T.; Sun, Z.; Fujino, Y.

    2012-04-01

    Recent progress in radar techniques and systems has led to the development of a microwave interferometer, potentially suitable for non-contact displacement monitoring of civil engineering structures. This paper describes a new interferometric radar system, named IBIS-S, which is possible to measure the static or dynamic displacement at multiple points of structures simultaneously with high accuracy. In this paper, the technical characteristics and specification of the radar system is described. Subsequently, the actual displacement sensitivity of the equipment is illustrated using the laboratory tests with random motion upon a shake table. Finally the applications of the radar system to the measurement on a cable-stayed bridge and a prestressed concrete bridge are presented and discussed. Results show that the new system is an accurate and effective method to measure displacements of multiple targets of structures. It should be noted that the current system can only measure the vibration of the target position along the sensor's line of sight. Hence, proper caution should be taken when designing the sensor posture and prior knowledge of the direction of motion is necessary.

  13. Intelligent Flexible Materials for Space Structures: Expandable Habitat Engineering Development Unit

    Science.gov (United States)

    Hinkle, Jon; Sharpe, George; Lin, John; Wiley, Cliff; Timmers, Richard

    2010-01-01

    Expandable habitable elements are an enabling technology for human exploration in space and on planetary surfaces. Large geometries can be deployed from a small launch volume, allowing greater mission capability while reducing mass and improving robustness over traditional rigid shells. This report describes research performed by ILC Dover under the Intelligent Flexible Materials for Space Structures program on the design and manufacture of softgoods for LaRC's Expandable Habitat Engineering Development Unit (EDU). The EDU is a full-scale structural test article of an expandable hybrid habitat, integrating an expandable softgoods center section with two rigid end caps. The design of the bladder, restraint layer and a mock-up Thermal Micrometeoroid Cover is detailed together with the design of the interface hardware used to attach them to the end caps. The integration and design of two windows and a floor are also covered. Analysis was performed to study the effects of the open weave design, and to determine the correct webbing and fabric configuration. Stress analyses were also carried out on the interfaces between the softgoods and the end caps and windows. Testing experimentally determined the strength of the fabric and straps, and component testing was used to proof several critical parts of the design. This program established new manufacturing and design techniques that can be applied to future applications in expandable structures.

  14. Structural Analysis and Optimization of a Composite Fan Blade for Future Aircraft Engine

    Science.gov (United States)

    Coroneos, Rula M.

    2012-01-01

    This report addresses the structural analysis and optimization of a composite fan blade sized for a large aircraft engine. An existing baseline solid metallic fan blade was used as a starting point to develop a hybrid honeycomb sandwich construction with a polymer matrix composite face sheet and honeycomb aluminum core replacing the original baseline solid metallic fan model made of titanium. The focus of this work is to design the sandwich composite blade with the optimum number of plies for the face sheet that will withstand the combined pressure and centrifugal loads while the constraints are satisfied and the baseline aerodynamic and geometric parameters are maintained. To satisfy the requirements, a sandwich construction for the blade is proposed with composite face sheets and a weak core made of honeycomb aluminum material. For aerodynamic considerations, the thickness of the core is optimized whereas the overall blade thickness is held fixed so as to not alter the original airfoil geometry. Weight is taken as the objective function to be minimized by varying the core thickness of the blade within specified upper and lower bounds. Constraints are imposed on radial displacement limitations and ply failure strength. From the optimum design, the minimum number of plies, which will not fail, is back-calculated. The ply lay-up of the blade is adjusted from the calculated number of plies and final structural analysis is performed. Analyses were carried out by utilizing the OpenMDAO Framework, developed at NASA Glenn Research Center combining optimization with structural assessment.

  15. Structural transition, subgap states, and carrier transport in anion-engineered zinc oxynitride nanocrystalline films

    International Nuclear Information System (INIS)

    Xian, Fenglin; Ye, Jiandong; Gu, Shulin; Tan, Hark Hoe; Jagadish, Chennupati

    2016-01-01

    In this work, anion alloying is engineered in ZnON nanocrystalline films, and the resultant evolution of the structural transition, subgap states, and carrier transport is investigated. A broad distribution of sub-gap states above the valence band maximum is introduced by nitrogen due to the hybridization of N 2p and O 2p orbitals. The phase transition from partially amorphous states to full crystallinity occurs above a characteristic growth temperature of 100 °C, and the localized states are suppressed greatly due to the reduction of nitrogen composition. The electronic properties are dominated by grain boundary scattering and electron transport across boundary barriers through thermal activation at band edge states at high temperatures. The conductivity below 130 K exhibits a weak temperature dependence, which is a signature of variable-range hopping conduction between localized states introduced by nitrogen incorporation.

  16. Structural transition, subgap states, and carrier transport in anion-engineered zinc oxynitride nanocrystalline films

    Energy Technology Data Exchange (ETDEWEB)

    Xian, Fenglin [School of Physics and Optoelectronic Engineering, Nanjing University of Information Science and Technology, Nanjing 210044 (China); Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra 2601 (Australia); Ye, Jiandong, E-mail: yejd@nju.edu.cn [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra 2601 (Australia); School of Electronics Science and Engineering, Nanjing University, Nanjing 210093 (China); Gu, Shulin [School of Electronics Science and Engineering, Nanjing University, Nanjing 210093 (China); Tan, Hark Hoe; Jagadish, Chennupati [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra 2601 (Australia)

    2016-07-11

    In this work, anion alloying is engineered in ZnON nanocrystalline films, and the resultant evolution of the structural transition, subgap states, and carrier transport is investigated. A broad distribution of sub-gap states above the valence band maximum is introduced by nitrogen due to the hybridization of N 2p and O 2p orbitals. The phase transition from partially amorphous states to full crystallinity occurs above a characteristic growth temperature of 100 °C, and the localized states are suppressed greatly due to the reduction of nitrogen composition. The electronic properties are dominated by grain boundary scattering and electron transport across boundary barriers through thermal activation at band edge states at high temperatures. The conductivity below 130 K exhibits a weak temperature dependence, which is a signature of variable-range hopping conduction between localized states introduced by nitrogen incorporation.

  17. GPCR engineering yields high-resolution structural insights into beta2-adrenergic receptor function

    DEFF Research Database (Denmark)

    Rosenbaum, Daniel M; Cherezov, Vadim; Hanson, Michael A

    2007-01-01

    crystallization, we engineered a beta2AR fusion protein in which T4 lysozyme (T4L) replaces most of the third intracellular loop of the GPCR ("beta2AR-T4L") and showed that this protein retains near-native pharmacologic properties. Analysis of adrenergic receptor ligand-binding mutants within the context......The beta2-adrenergic receptor (beta2AR) is a well-studied prototype for heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors (GPCRs) that respond to diffusible hormones and neurotransmitters. To overcome the structural flexibility of the beta2AR and to facilitate its...... a conformational pathway from the ligand-binding pocket to regions that interact with G proteins....

  18. Design of Offshore Wind Turbine Support Structures: Selected topics in the field of geotechnical engineering

    DEFF Research Database (Denmark)

    Bakmar, Christian LeBlanc

    Breaking the dependence on fossil fuels offers many opportunities for strengthened competitiveness, technological development and progress. Offshore wind power is a domestic, sustainable and largely untapped energy resource that provides an alternative to fossil fuels, reduces carbon emissions......, and decreases the economic and supply risks associated with reliance on imported fuels. Today, the modern offshore wind turbine offers competitive production prices for renewable energy and is therefore a key technology in achieving the energy and climate goals of the future. The overall aim of this Ph.......D. thesis was to enable low-cost and low-risk support structures to be designed in order to improve the economic feasibility of future offshore wind farms. The research work was divided in the following four selected research topics in the field of geotechnical engineering, relating to the monopile...

  19. Defect formation and electronic structure regulated by strain engineering in ReS2

    Science.gov (United States)

    Min, Y. M.; Wang, A. Q.; Ren, X. M.; Liu, L. Z.; Wu, X. L.

    2018-01-01

    By using first-principles calculations, we investigated the monolayer ReS2 with vacancies under strain engineering, specifically focusing on its energy of formation, band gap, electron density of states, effective mass and optical properties. The calculated results disclose that S4 defect is more likely to form than other kinds of vacancies. Asymmetric deformation induced by strain makes its band structure transformation from direct band gap to indirect band gap. The analysis of the partial density of states indicates that the Re-d and S-p orbitals are the major components of the defect states, being different from MoS2, the defect states locate both above and below the Fermi level. Moreover, the effective mass was sensitive and anisotropic under the external strain. The reflection spectrum can be greatly tuned by the external strains, which indicates that the ReS2 monolayer has promising applications in nanoscale strain sensor and conductance-switch FETs.

  20. 75 FR 59067 - Airworthiness Directives; International Aero Engines AG V2500-A1, V2522-A5, V2524-A5, V2525-D5...

    Science.gov (United States)

    2010-09-27

    ...) of this AD. Definitions (h) For the purpose of this AD, an engine shop visit is the induction of an... Airworthiness Directives; International Aero Engines AG V2500-A1, V2522-A5, V2524-A5, V2525-D5, V2527-A5, V2527E-A5, V2527M-A5, V2528-D5, V2530-A5, and V2533-A5 Turbofan Engines AGENCY: Federal Aviation...

  1. Engineered, highly reactive substrates of microbial transglutaminase enable protein labeling within various secondary structure elements.

    Science.gov (United States)

    Rachel, Natalie M; Quaglia, Daniela; Lévesque, Éric; Charette, André B; Pelletier, Joelle N

    2017-11-01

    Microbial transglutaminase (MTG) is a practical tool to enzymatically form isopeptide bonds between peptide or protein substrates. This natural approach to crosslinking the side-chains of reactive glutamine and lysine residues is solidly rooted in food and textile processing. More recently, MTG's tolerance for various primary amines in lieu of lysine have revealed its potential for site-specific protein labeling with aminated compounds, including fluorophores. Importantly, MTG can label glutamines at accessible positions in the body of a target protein, setting it apart from most labeling enzymes that react exclusively at protein termini. To expand its applicability as a labeling tool, we engineered the B1 domain of Protein G (GB1) to probe the selectivity and enhance the reactivity of MTG toward its glutamine substrate. We built a GB1 library where each variant contained a single glutamine at positions covering all secondary structure elements. The most reactive and selective variants displayed a >100-fold increase in incorporation of a recently developed aminated benzo[a]imidazo[2,1,5-cd]indolizine-type fluorophore, relative to native GB1. None of the variants were destabilized. Our results demonstrate that MTG can react readily with glutamines in α-helical, β-sheet, and unstructured loop elements and does not favor one type of secondary structure. Introducing point mutations within MTG's active site further increased reactivity toward the most reactive substrate variant, I6Q-GB1, enhancing MTG's capacity to fluorescently label an engineered, highly reactive glutamine substrate. This work demonstrates that MTG-reactive glutamines can be readily introduced into a protein domain for fluorescent labeling. © 2017 The Protein Society.

  2. Molecular Basis of Clay Mineral Structure and Dynamics in Subsurface Engineering Applications

    Science.gov (United States)

    Cygan, R. T.

    2015-12-01

    Clay minerals and their interfaces play an essential role in many geochemical, environmental, and subsurface engineering applications. Adsorption, dissolution, precipitation, nucleation, and growth mechanisms, in particular, are controlled by the interplay of structure, thermodynamics, kinetics, and transport at clay mineral-water interfaces. Molecular details of these processes are typically beyond the sensitivity of experimental and analytical methods, and therefore require accurate models and simulations. Also, basal surfaces and interlayers of clay minerals provide constrained interfacial environments to facilitate the evaluation of these complex processes. We have developed and used classical molecular and quantum methods to examine the complex behavior of clay mineral-water interfaces and dynamics of interlayer species. Bulk structures, swelling behavior, diffusion, and adsorption processes are evaluated and compared to experimental and spectroscopic findings. Analysis of adsorption mechanisms of radionuclides on clay minerals provides a scientific basis for predicting the suitability of engineered barriers associated with nuclear waste repositories and the fate of contaminants in the environment. Similarly, the injection of supercritical carbon dioxide into geological reservoirs—to mitigate the impact of climate change—is evaluated by molecular models of multi-fluid interactions with clay minerals. Molecular dynamics simulations provide insights into the wettability of different fluids—water, electrolyte solutions, and supercritical carbon dioxide—on clay surfaces, and which ultimately affects capillary fluid flow and the integrity of shale caprocks. This work is supported as part of Center for Frontiers of Subsurface Energy Security, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science and by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Geosciences Research Program

  3. A structural model for the flexural mechanics of nonwoven tissue engineering scaffolds.

    Science.gov (United States)

    Engelmayr, George C; Sacks, Michael S

    2006-08-01

    The development of methods to predict the strength and stiffness of biomaterials used in tissue engineering is critical for load-bearing applications in which the essential functional requirements are primarily mechanical. We previously quantified changes in the effective stiffness (E) of needled nonwoven polyglycolic acid (PGA) and poly-L-lactic acid (PLLA) scaffolds due to tissue formation and scaffold degradation under three-point bending. Toward predicting these changes, we present a structural model for E of a needled nonwoven scaffold in flexure. The model accounted for the number and orientation of fibers within a representative volume element of the scaffold demarcated by the needling process. The spring-like effective stiffness of the curved fibers was calculated using the sinusoidal fiber shapes. Structural and mechanical properties of PGA and PLLA fibers and PGA, PLLA, and 50:50 PGA/PLLA scaffolds were measured and compared with model predictions. To verify the general predictive capability, the predicted dependence of E on fiber diameter was compared with experimental measurements. Needled nonwoven scaffolds were found to exhibit distinct preferred (PD) and cross-preferred (XD) fiber directions, with an E ratio (PD/XD) of approximately 3:1. The good agreement between the predicted and experimental dependence of E on fiber diameter (R2 = 0.987) suggests that the structural model can be used to design scaffolds with E values more similar to native soft tissues. A comparison with previous results for cell-seeded scaffolds (Engelmayr, G. C., Jr., et al., 2005, Biomaterials, 26(2), pp. 175-187) suggests, for the first time, that the primary mechanical effect of collagen deposition is an increase in the number of fiber-fiber bond points yielding effectively stiffer scaffold fibers. This finding indicated that the effects of tissue deposition on needled nonwoven scaffold mechanics do not follow a rule-of-mixtures behavior. These important results underscore

  4. Image restoration for civil engineering structure monitoring using imaging system embedded on UAV

    Science.gov (United States)

    Vozel, Benoit; Dumoulin, Jean; Chehdi, Kacem

    2013-04-01

    Nowadays, civil engineering structures are periodically surveyed by qualified technicians (i.e. alpinist) operating visual inspection using heavy mechanical pods. This method is far to be safe, not only for civil engineering structures monitoring staff, but also for users. Due to the unceasing traffic increase, making diversions or closing lanes on bridge becomes more and more difficult. New inspection methods have to be found. One of the most promising technique is to develop inspection method using images acquired by a dedicated monitoring system operating around the civil engineering structures, without disturbing the traffic. In that context, the use of images acquired with an UAV, which fly around the structures is of particular interest. The UAV can be equipped with different vision system (digital camera, infrared sensor, video, etc.). Nonetheless, detection of small distresses on images (like cracks of 1 mm or less) depends on image quality, which is sensitive to internal parameters of the UAV (vibration modes, video exposure times, etc.) and to external parameters (turbulence, bad illumination of the scene, etc.). Though progresses were made at UAV level and at sensor level (i.e. optics), image deterioration is still an open problem. These deteriorations are mainly represented by motion blur that can be coupled with out-of-focus blur and observation noise on acquired images. In practice, deteriorations are unknown if no a priori information is available or dedicated additional instrumentation is set-up at UAV level. Image restoration processing is therefore required. This is a difficult problem [1-3] which has been intensively studied over last decades [4-12]. Image restoration can be addressed by following a blind approach or a myopic one. In both cases, it includes two processing steps that can be implemented in sequential or alternate mode. The first step carries out the identification of the blur impulse response and the second one makes use of this

  5. Introduction of Functional Structures in Nano-Scales into Engineering Polymer Films Using Radiation Technique

    International Nuclear Information System (INIS)

    Maekawa, Y.

    2010-01-01

    Introduction of functional regions in nanometer scale in polymeric films using γ-rays, EB, and ion beams are proposed. Two approaches to build nano-scale functional domains in polymer substrates are proposed: 1) Radiation-induced grafting to transfer nano-scale polymer crystalline structures (morphology), acting as a nano-template, to nano-scale graft polymer regions. The obtained polymers with nano structures can be applied to high performance polymer membranes. 2) Fabrication of nanopores and functional domains in engineering plastic films using ion beams, which deposit the energy in very narrow region of polymer films. Hydrophilic grafting polymers are introduced into hydrophobic fluorinated polymers, cross-linked PTFE (cPTFE) and aromatic hydrocarbon polymer, poly(ether ether ketone (PEEK), which is known to have lamella and crystallite in the polymer films. Then, the hierarchical structures of graft domains are analyzed by a small angle neutron scattering (SANS) experiment. From these analyses, the different structures and the different formation of graft domains were observed in fluorinated and hydrocarbon polymer substrates. the grafted domains in the cPTFE film, working as an ion channel, grew as covering the crystallite and the size of domain seems to be similar to that of crystallite. On the other hand, the PEEK-based PEM has a smaller domain size and it seems to grow independently on the crystallites of PEEK substrate. For nano-fabrication of polymer films using heavy ion beams, the energy distribution in radial direction, which is perpendicular to ion trajectory, is mainly concerned. For penumbra, we re-estimated effective radius of penumbra, in which radiation induced grafting took place, for several different ion beams. We observed the different diameters of the ion channels consisting of graft polymers. The channel sizes were quite in good agreement with the effective penumbra which possess the absorption doses more than 1 kGy. (author)

  6. Automating gene library synthesis by structure-based combinatorial protein engineering: examples from plant sesquiterpene synthases.

    Science.gov (United States)

    Dokarry, Melissa; Laurendon, Caroline; O'Maille, Paul E

    2012-01-01

    Structure-based combinatorial protein engineering (SCOPE) is a homology-independent recombination method to create multiple crossover gene libraries by assembling defined combinations of structural elements ranging from single mutations to domains of protein structure. SCOPE was originally inspired by DNA shuffling, which mimics recombination during meiosis, where mutations from parental genes are "shuffled" to create novel combinations in the resulting progeny. DNA shuffling utilizes sequence identity between parental genes to mediate template-switching events (the annealing and extension of one parental gene fragment on another) in PCR reassembly reactions to generate crossovers and hence recombination between parental genes. In light of the conservation of protein structure and degeneracy of sequence, SCOPE was developed to enable the "shuffling" of distantly related genes with no requirement for sequence identity. The central principle involves the use of oligonucleotides to encode for crossover regions to choreograph template-switching events during PCR assembly of gene fragments to create chimeric genes. This approach was initially developed to create libraries of hybrid DNA polymerases from distantly related parents, and later developed to create a combinatorial mutant library of sesquiterpene synthases to explore the catalytic landscapes underlying the functional divergence of related enzymes. This chapter presents a simplified protocol of SCOPE that can be integrated with different mutagenesis techniques and is suitable for automation by liquid-handling robots. Two examples are presented to illustrate the application of SCOPE to create gene libraries using plant sesquiterpene synthases as the model system. In the first example, we outline how to create an active-site library as a series of complex mixtures of diverse mutants. In the second example, we outline how to create a focused library as an array of individual clones to distil minimal combinations of

  7. Tuning Electronic Structure of Single Layer MoS2through Defect and Interface Engineering.

    Science.gov (United States)

    Chen, Yan; Huang, Shengxi; Ji, Xiang; Adepalli, Kiran; Yin, Kedi; Ling, Xi; Wang, Xinwei; Xue, Jianmin; Dresselhaus, Mildred; Kong, Jing; Yildiz, Bilge

    2018-03-27

    Transition-metal dichalcogenides (TMDs) have emerged in recent years as a special group of two-dimensional materials and have attracted tremendous attention. Among these TMD materials, molybdenum disulfide (MoS 2 ) has shown promising applications in electronics, photonics, energy, and electrochemistry. In particular, the defects in MoS 2 play an essential role in altering the electronic, magnetic, optical, and catalytic properties of MoS 2 , presenting a useful way to engineer the performance of MoS 2 . The mechanisms by which lattice defects affect the MoS 2 properties are unsettled. In this work, we reveal systematically how lattice defects and substrate interface affect MoS 2 electronic structure. We fabricated single-layer MoS 2 by chemical vapor deposition and then transferred onto Au, single-layer graphene, hexagonal boron nitride, and CeO 2 as substrates and created defects in MoS 2 by ion irradiation. We assessed how these defects and substrates affect the electronic structure of MoS 2 by performing X-ray photoelectron spectroscopy, Raman and photoluminescence spectroscopies, and scanning tunneling microscopy/spectroscopy measurements. Molecular dynamics and first-principles based simulations allowed us to conclude the predominant lattice defects upon ion irradiation and associate those with the experimentally obtained electronic structure. We found that the substrates can tune the electronic energy levels in MoS 2 due to charge transfer at the interface. Furthermore, the reduction state of CeO 2 as an oxide substrate affects the interface charge transfer with MoS 2 . The irradiated MoS 2 had a faster hydrogen evolution kinetics compared to the as-prepared MoS 2 , demonstrating the concept of defect controlled reactivity in this phase. Our findings provide effective probes for energy band and defects in MoS 2 and show the importance of defect engineering in tuning the functionalities of MoS 2 and other TMDs in electronics, optoelectronics, and

  8. 3D printing in chemical engineering and catalytic technology: structured catalysts, mixers and reactors.

    Science.gov (United States)

    Parra-Cabrera, Cesar; Achille, Clement; Kuhn, Simon; Ameloot, Rob

    2018-01-02

    Computer-aided fabrication technologies combined with simulation and data processing approaches are changing our way of manufacturing and designing functional objects. Also in the field of catalytic technology and chemical engineering the impact of additive manufacturing, also referred to as 3D printing, is steadily increasing thanks to a rapidly decreasing equipment threshold. Although still in an early stage, the rapid and seamless transition between digital data and physical objects enabled by these fabrication tools will benefit both research and manufacture of reactors and structured catalysts. Additive manufacturing closes the gap between theory and experiment, by enabling accurate fabrication of geometries optimized through computational fluid dynamics and the experimental evaluation of their properties. This review highlights the research using 3D printing and computational modeling as digital tools for the design and fabrication of reactors and structured catalysts. The goal of this contribution is to stimulate interactions at the crossroads of chemistry and materials science on the one hand and digital fabrication and computational modeling on the other.

  9. Mitigation of seismic action on engineering structure by innovative SERB - CITON Solution

    International Nuclear Information System (INIS)

    Serban, V.; Panait, A.; Androne, M.; Ciocan, G. A.

    2009-01-01

    The paper presents the advantage of the SERB-CITON innovative solution for increasing the seismic resistance of engineering structures as compared with other solutions for seismic protection of buildings. SERB devices (telescopic and isolation) used in an innovative solution to control, limit and damp the seismic building movement, have a capsulated structure and are capable to overtake large compression and tension loads with controlled deflection and large damping. The great difference in the building behavior during an earthquake results from the fact that a building (along with its foundation ground) make-up an oscillating system which represents a built-up of kinetic and potential energy of repeated seismic movement oscillations. The oscillating system may or not overtake and built-up the seismic energy from each soil oscillation, as a function of the location of the important Eigen vibration periods of the building within the spectral component of the seismic action. The main problem that needs to be solved by the seismic design of buildings consists in the transfer of a minimum amount of seismic energy from the ground to the building and in doing so for the transferred energy should not build-up in the building-ground oscillating system. The paper presents the classical, modern and innovative solution for mitigation of seismic actions. (authors)

  10. BioGPS descriptors for rational engineering of enzyme promiscuity and structure based bioinformatic analysis.

    Directory of Open Access Journals (Sweden)

    Valerio Ferrario

    Full Text Available A new bioinformatic methodology was developed founded on the Unsupervised Pattern Cognition Analysis of GRID-based BioGPS descriptors (Global Positioning System in Biological Space. The procedure relies entirely on three-dimensional structure analysis of enzymes and does not stem from sequence or structure alignment. The BioGPS descriptors account for chemical, geometrical and physical-chemical features of enzymes and are able to describe comprehensively the active site of enzymes in terms of "pre-organized environment" able to stabilize the transition state of a given reaction. The efficiency of this new bioinformatic strategy was demonstrated by the consistent clustering of four different Ser hydrolases classes, which are characterized by the same active site organization but able to catalyze different reactions. The method was validated by considering, as a case study, the engineering of amidase activity into the scaffold of a lipase. The BioGPS tool predicted correctly the properties of lipase variants, as demonstrated by the projection of mutants inside the BioGPS "roadmap".

  11. Fabrication of polycaprolactone electrospun fibers with different hierarchical structures mimicking collagen fibrils for tissue engineering scaffolds

    Science.gov (United States)

    Jiang, Lin; Wang, Liwei; Wang, Nathan; Gong, Shaoqin; Wang, Lixia; Li, Qian; Shen, Changyu; Turng, Lih-Sheng

    2018-01-01

    The ability to topographically mimic the surface features of collagen fibrils is an important step in the preparation of tissue engineering scaffolds. It is important to know which kinds of surface topographies of electrospun fibers are more favorable for cell growth. In this study, fibers with three kinds of hierarchical-structured surfaces were fabricated by electrospinning to mimic collagen fibrils. By combining thermally induced phase separation (TIPS) and non-solvent induced phase separation (NIPS), polycaprolactone (PCL) fibers with a porous surface were electrospun from PCL in a chloroform (CF)/dimethyl sulfoxide (DMSO) mixed solution. In addition, two additional types of fibrous membranes, with PCL fibers being the shish and decorated by PCL kebabs on the surface, were created by two different controlled homoepitaxic crystallization methods-the solution incubation method and the solvent evaporation method. It was found that the solvent evaporation method was more effective in forming kebabs and the primary optimal processing parameters were identified. The presence of pores on the fiber surfaces contributed to a much larger surface area and a higher total volume of pores. To investigate the cellular response on such scaffolds, 3T3 fibroblast cell and human umbilical vein endothelial cell (HUVEC) assays were conducted and the results indicated that both of the nanotopographies on the surfaces of the scaffolds improved cell viability and proliferation. Furthermore, the porous surface was more beneficial for enhancing cellular responses, which suggests better biocompatibility and greater potential to mimic collagen fibrils for tissue engineering application, and especially as scaffolds for endothelial layers in blood vessels.

  12. Regeneration of Vocal Fold Mucosa Using Tissue-Engineered Structures with Oral Mucosal Cells.

    Directory of Open Access Journals (Sweden)

    Mioko Fukahori

    Full Text Available Scarred vocal folds result in irregular vibrations during phonation due to stiffness of the vocal fold mucosa. To date, a completely satisfactory corrective procedure has yet to be achieved. We hypothesize that a potential treatment option for this disease is to replace scarred vocal folds with organotypic mucosa. The purpose of this study is to regenerate vocal fold mucosa using a tissue-engineered structure with autologous oral mucosal cells.Animal experiment using eight beagles (including three controls.A 3 mm by 3 mm specimen of canine oral mucosa was surgically excised and divided into epithelial and subepithelial tissues. Epithelial cells and fibroblasts were isolated and cultured separately. The proliferated epithelial cells were co-cultured on oriented collagen gels containing the proliferated fibroblasts for an additional two weeks. The organotypic cultured tissues were transplanted to the mucosa-deficient vocal folds. Two months after transplantation, vocal fold vibrations and morphological characteristics were observed.A tissue-engineered vocal fold mucosa, consisting of stratified epithelium and lamina propria, was successfully fabricated to closely resemble the normal layered vocal fold mucosa. Laryngeal stroboscopy revealed regular but slightly small mucosal waves at the transplanted site. Immunohistochemically, stratified epithelium expressed cytokeratin, and the distributed cells in the lamina propria expressed vimentin. Elastic Van Gieson staining revealed a decreased number of elastic fibers in the lamina propria of the transplanted site.The fabricated mucosa with autologous oral mucosal cells successfully restored the vocal fold mucosa. This reconstruction technique could offer substantial clinical advantages for treating intractable diseases such as scarring of the vocal folds.

  13. Impact of branched structures on cycloalkane ignition in a motored engine: Detailed product and conformational analyses

    KAUST Repository

    Kang, Dongil

    2015-04-01

    The ignition process of ethylcyclohexane (ECH) and its two isomers, 1,3-dimethylcyclohexane (13DMCH) and 1,2-dimethylcyclohexane (12DMCH) was investigated in a modified CFR engine. The experiment was conducted with intake air temperature of 155. °C, equivalence ratio of 0.5 and engine speed of 600. rpm. The engine compression ratio (CR) was gradually increased in a stepwise manner until autoignition occurred. It was found that ECH exhibited a significantly higher oxidation reactivity compared to its two isomers. The autoignition criterion was based on CO emissions and the apparent heat release rates. Ethylcyclohexane (ECH) indicated noticeable two stage ignition behavior, while less significant heat release occurred for the two isomers at comparable conditions. The mole fractions of unreacted fuel and stable intermediate species over a wide range of compression ratios were analyzed by GC-MS and GC-FID. Most of the species indicated constant rates of formation and the trends of relative yield to unreacted fuel are well in agreement with the oxidation reactivity in the low temperature regime. The major intermediate species are revealed as a group of conjugate olefins, which possess the same molecular structure as the original fuel compound except for the presence of a double carbon bond. Conjugate olefins were mostly formed through (1,4) H-shift isomerization during the low temperature oxidation of alkylcyclohexanes. Conformation analysis explains the reactivity differences in the three isomers as well as the fractions of intermediate species. The hydrogen availability located in alkyl substituents plays an important role in determining oxidation reactivity, requiring less activation energy for abstraction through the (1,5) H-shift isomerization. This reactivity difference contributes to building up the major intermediate species observed during oxidation of each test fuel. 12DMCH, whose ignition reactivity is the lowest, less favors β-scission of C-C backbone of

  14. Crack Growth-Based Predictive Methodology for the Maintenance of the Structural Integrity of Repaired and Nonrepaired Aging Engine Stationary Components

    National Research Council Canada - National Science Library

    Barron, Michael

    1999-01-01

    .... Specifically, the FAA's goal was to develop "Crack Growth-Based Predictive Methodologies for the Maintenance of the Structural Integrity of Repaired and Nonrepaired Aging Engine Stationary Components...

  15. ENGINEERING-GEOLOGICAL CHARACTERISTICS OF THE LANDSLIDE MLIJA AND THEIR IMPACT ON ENGINEERING STRUCTURES (OMIŠ, SOUTHERN CROATIA

    Directory of Open Access Journals (Sweden)

    Slobodan Šestanović

    1998-12-01

    Full Text Available In order to design the by-pass road of the city of Omiš which will partially he founded on the landslide Mlija and for the safety of foundations of houses, detail subsurface exploration especially engineering-geological surveys, geophysical surveys, boring and laboratory tests of the sliding material were conducted. Obtained results are presented in this paper. Due to numerous damages of roads, walls and houses built in the area of Mlija and Borak, the possibility of construction in the area was discussed and the foundation method proposed. In order to obtain an overview of circumstances, constant monitoring of variations of the water table level and velocity of the moving material has been proposed.

  16. A paperless course on structural engineering programming: investing in educational technology in the times of the Greek financial recession

    Science.gov (United States)

    Sextos, Anastasios G.

    2014-01-01

    This paper presents the structure of an undergraduate course entitled 'programming techniques and the use of specialised software in structural engineering' which is offered to the fifth (final) year students of the Civil Engineering Department of Aristotle University Thessaloniki in Greece. The aim of this course is to demonstrate the use of new information technologies in the field of structural engineering and to teach modern programming and finite element simulation techniques that the students can in turn apply in both research and everyday design of structures. The course also focuses on the physical interpretation of structural engineering problems, in a way that the students become familiar with the concept of computational tools without losing perspective from the engineering problem studied. For this purpose, a wide variety of structural engineering problems are studied in class, involving structural statics, dynamics, earthquake engineering, design of reinforced concrete and steel structures as well as data and information management. The main novelty of the course is that it is taught and examined solely in the computer laboratory ensuring that each student can accomplish the prescribed 'hands-on' training on a dedicated computer, strictly on a 1:1 student over hardware ratio. Significant effort has also been put so that modern educational techniques and tools are utilised to offer the course in an essentially paperless mode. This involves electronic educational material, video tutorials, student information in real time and exams given and assessed electronically through an ad hoc developed, personalised, electronic system. The positive feedback received from the students reveals that the concept of a paperless course is not only applicable in real academic conditions but is also a promising approach that significantly increases student productivity and engagement. The question, however, is whether such an investment in educational technology is indeed

  17. Engineered Biosynthesis of Plant Polyketides: Structure-Based and Precursor-Directed Approach

    Science.gov (United States)

    Abe, Ikuro

    benzoyl-CoA as a starter substrate. These results suggested that the engineered biosynthesis of plant polyketides by combination of the structure-based and the precursor-directed approach would lead to further production of chemically and structurally divergent unnatural novel polyketides.

  18. Conceptual study of advanced VTOL transport aircraft engine; Kosoku VTOL kiyo engine no gainen kento

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Y.; Endo, M.; Matsuda, Y.; Sugiyama, N.; Watanabe, M.; Sugahara, N.; Yamamoto, K. [National Aerospace Laboratory, Tokyo (Japan)

    1996-04-01

    This report proposes the concept of an ultra-low noise engine for advanced high subsonic VTOL transport aircraft, and discusses its technological feasibility. As one of the applications of the previously reported `separated core turbofan engine,` the conceptual engine is composed of 3 core engines, 2 cruise fan engines for high subsonic cruising and 6 lift fan engines producing thrust of 98kN (10000kgf)/engine. The core turbojet engine bleeds a large amount of air at the outlet of a compressor to supply driving high-pressure air for fans to other engines. The lift fan engine is composed of a lift fan, driving combustor, turbine and speed reduction gear, and is featured by not only high operation stability and thin fan engine like a separated core engine but also ultra-low noise operation. The cruise fan engine adopts the same configuration as the lift fan engine. Since this engine configuration has no technological problems difficult to be overcome, its high technological feasibility is expected. 6 refs., 7 figs., 5 tabs.

  19. Preliminary core-engine noise abatement experimental results of a fluid injection nozzle on a JT-15D turbofan engine

    Science.gov (United States)

    Cheng, D. Y.; Wang, P.

    1975-01-01

    Jet noise, as induced by shear stress, in an jet exhaust is investigated. Experiments were performed on a JT-15D fan jet to verify the inward momentum stress reduction concept. The experiments involved making fan air flow convergently around the high velocity core jet with a small angle. Ring airfoils were used as flow separators for the minimization of the thrust loss. Jet exhaust noise reduction of ll db at 30 deg from the jet axis was recorded and 8 db integrated overall noise reduction over a hemisphere was measured with only 4.6% thrust loss, or 152 db/percent thrust loss.

  20. Structural Engineering of Nanoporous Anodic Alumina Photonic Crystals by Sawtooth-like Pulse Anodization.

    Science.gov (United States)

    Law, Cheryl Suwen; Santos, Abel; Nemati, Mahdieh; Losic, Dusan

    2016-06-01

    This study presents a sawtooth-like pulse anodization approach aiming to create a new type of photonic crystal structure based on nanoporous anodic alumina. This nanofabrication approach enables the engineering of the effective medium of nanoporous anodic alumina in a sawtooth-like manner with precision. The manipulation of various anodization parameters such as anodization period, anodization amplitude, number of anodization pulses, ramp ratio and pore widening time allows a precise control and fine-tuning of the optical properties (i.e., characteristic transmission peaks and interferometric colors) exhibited by nanoporous anodic alumina photonic crystals (NAA-PCs). The effect of these anodization parameters on the photonic properties of NAA-PCs is systematically evaluated for the establishment of a fabrication methodology toward NAA-PCs with tunable optical properties. The effective medium of the resulting NAA-PCs is demonstrated to be optimal for the development of optical sensing platforms in combination with reflectometric interference spectroscopy (RIfS). This application is demonstrated by monitoring in real-time the formation of monolayers of thiol molecules (11-mercaptoundecanoic acid) on the surface of gold-coated NAA-PCs. The obtained results reveal that the adsorption mechanism between thiol molecules and gold-coated NAA-PCs follows a Langmuir isotherm model, indicating a monolayer sorption mechanism.

  1. Polymer structure-property requirements for stereolithographic 3D printing of soft tissue engineering scaffolds.

    Science.gov (United States)

    Mondschein, Ryan J; Kanitkar, Akanksha; Williams, Christopher B; Verbridge, Scott S; Long, Timothy E

    2017-09-01

    This review highlights the synthesis, properties, and advanced applications of synthetic and natural polymers 3D printed using stereolithography for soft tissue engineering applications. Soft tissue scaffolds are of great interest due to the number of musculoskeletal, cardiovascular, and connective tissue injuries and replacements humans face each year. Accurately replacing or repairing these tissues is challenging due to the variation in size, shape, and strength of different types of soft tissue. With advancing processing techniques such as stereolithography, control of scaffold resolution down to the μm scale is achievable along with the ability to customize each fabricated scaffold to match the targeted replacement tissue. Matching the advanced manufacturing technique to polymer properties as well as maintaining the proper chemical, biological, and mechanical properties for tissue replacement is extremely challenging. This review discusses the design of polymers with tailored structure, architecture, and functionality for stereolithography, while maintaining chemical, biological, and mechanical properties to mimic a broad range of soft tissue types. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Effect of engineered environment on microbial community structure in biofilter and biofilm on reverse osmosis membrane.

    Science.gov (United States)

    Jeong, Sanghyun; Cho, Kyungjin; Jeong, Dawoon; Lee, Seockheon; Leiknes, TorOve; Vigneswaran, Saravanamuthu; Bae, Hyokwan

    2017-11-01

    Four dual media filters (DMFs) were operated in a biofiltration mode with different engineered environments (DMF I and II: coagulation with/without acidification and DMF III and IV: without/with chlorination). Designed biofilm enrichment reactors (BERs) containing the removable reverse osmosis (RO) coupons, were connected at the end of the DMFs in parallel to analyze the biofilm on the RO membrane by DMF effluents. Filtration performances were evaluated in terms of dissolved organic carbon (DOC) and assimilable organic carbon (AOC). Organic foulants on the RO membrane were also quantified and fractionized. The bacterial community structures in liquid (seawater and effluent) and biofilm (DMF and RO) samples were analyzed using 454-pyrosequencing. The DMF IV fed with the chlorinated seawater demonstrated the highest reductions of DOC including LMW-N as well as AOC among the other DMFs. The DMF IV was also effective in reducing organic foulants on the RO membrane surface. The bacterial community structure was grouped according to the sample phase (i.e., liquid and biofilm samples), sampling location (i.e., DMF and RO samples), and chlorination (chlorinated and non-chlorinated samples). In particular, the biofilm community in the DMF IV differed from the other DMF treatments, suggesting that chlorination exerted as stronger selective pressure than pH adjustment or coagulation on the biofilm community. In the DMF IV, several chemoorganotrophic chlorine-resistant biofilm-forming bacteria such as Hyphomonas, Erythrobacter, and Sphingomonas were predominant, and they may enhance organic carbon degradation efficiency. Diverse halophilic or halotolerant organic degraders were also found in other DMFs (i.e., DMF I, II, and III). Various kinds of dominant biofilm-forming bacteria were also investigated in RO membrane samples; the results provided possible candidates that cause biofouling when DMF process is applied as the pretreatment option for the RO process. Copyright

  3. Effect of engineered environment on microbial community structure in biofilter and biofilm on reverse osmosis membrane

    KAUST Repository

    Jeong, Sanghyun

    2017-07-25

    Four dual media filters (DMFs) were operated in a biofiltration mode with different engineered environments (DMF I and II: coagulation with/without acidification and DMF III and IV: without/with chlorination). Designed biofilm enrichment reactors (BERs) containing the removable reverse osmosis (RO) coupons, were connected at the end of the DMFs in parallel to analyze the biofilm on the RO membrane by DMF effluents. Filtration performances were evaluated in terms of dissolved organic carbon (DOC) and assimilable organic carbon (AOC). Organic foulants on the RO membrane were also quantified and fractionized. The bacterial community structures in liquid (seawater and effluent) and biofilm (DMF and RO) samples were analyzed using 454-pyrosequencing. The DMF IV fed with the chlorinated seawater demonstrated the highest reductions of DOC including LMW-N as well as AOC among the other DMFs. The DMF IV was also effective in reducing organic foulants on the RO membrane surface. The bacterial community structure was grouped according to the sample phase (i.e., liquid and biofilm samples), sampling location (i.e., DMF and RO samples), and chlorination (chlorinated and non-chlorinated samples). In particular, the biofilm community in the DMF IV differed from the other DMF treatments, suggesting that chlorination exerted as stronger selective pressure than pH adjustment or coagulation on the biofilm community. In the DMF IV, several chemoorganotrophic chlorine-resistant biofilm-forming bacteria such as Hyphomonas, Erythrobacter, and Sphingomonas were predominant, and they may enhance organic carbon degradation efficiency. Diverse halophilic or halotolerant organic degraders were also found in other DMFs (i.e., DMF I, II, and III). Various kinds of dominant biofilm-forming bacteria were also investigated in RO membrane samples; the results provided possible candidates that cause biofouling when DMF process is applied as the pretreatment option for the RO process.

  4. Use of DXA-Based Structural Engineering Models of the Proximal Femur to Discriminate Hip Fracture

    Science.gov (United States)

    Yang, Lang; Peel, Nicola; Clowes, Jackie A; McCloskey, Eugene V; Eastell, Richard

    2011-01-01

    Several DXA-based structural engineering models (SEMs) of the proximal femur have been developed to estimate stress caused by sideway falls. Their usefulness in discriminating hip fracture has not yet been established and we therefore evaluated these models. The hip DXA scans of 51 postmenopausal women with hip fracture (30 femoral neck, 17 trochanteric, and 4 unspecified) and 153 age-, height-, and weight-matched controls were reanalyzed using a special version of Hologic’s software that produced a pixel-by-pixel BMD map. For each map, a curved-beam, a curved composite-beam, and a finite element model were generated to calculate stress within the bone when falling sideways. An index of fracture risk (IFR) was defined over the femoral neck, trochanter, and total hip as the stress divided by the yield stress at each pixel and averaged over the regions of interest. Hip structure analysis (HSA) was also performed using Hologic APEX analysis software. Hip BMD and almost all parameters derived from HSA and SEM were discriminators of hip fracture on their own because their ORs were significantly >1. Because of the high correlation of total hip BMD to HSA and SEM-derived parameters, only the bone width discriminated hip fracture independently from total hip BMD. Judged by the area under the receiver operating characteristics curve, the trochanteric IFR derived from the finite element model was significant better than total hip BMD alone and similar to the total hip BMD plus bone width in discriminating all hip fracture and femoral neck fracture. No index was better than total hip BMD for discriminating trochanteric fractures. In conclusion, the finite element model has the potential to replace hip BMD in discriminating hip fractures. PMID:18767924

  5. Corps of Engineers Structural Engineering Conference Held in St. Johns County, Florida on 8-12 July 1991. Volume 1

    Science.gov (United States)

    1992-12-01

    25 Portugues Dam Monolith Layout and Survey Control ...................... 33 Cofferdam Design Problems, Point...10:30 a.m. Olmsted L&D - Holly Gittings, Jeffrey Bayers (ORL) 11:00 a.m. Portuguese Dam & Monolith Layout & Survey Control - William Wigner (SAJ...Demos "* Nonlinear Incremental Structural Analysis-NISA (WES) "* Portuguese Arch Dam Model (SAJ) "* Rio Puerto Nuevo - CADD Application (SAJ) "* Civil

  6. Analytical study of the effects of wind tunnel turbulence on turbofan rotor noise

    Science.gov (United States)

    Gliebe, P. R.

    1980-01-01

    An analytical study of the effects of wind tunnel turbulence on turbofan rotor noise was carried out to evaluate the effectiveness of the NASA Ames 40 by 80-foot wind tunnel in simulating flight levels of fan noise. A previously developed theory for predicting rotor/turbulence interaction noise, refined and extended to include first-order effects of inlet turbulence anisotropy, was employed to carry out a parametric study of the effects of fan size, blade number, and operating line for outdoor test stand, NASA Ames wind tunnel, and flight inlet turbulence conditions. A major result of this study is that although wind tunnel rotor/turbulence noise levels are not as low as flight levels, they are substantially lower than the outdoor test stand levels and do not mask other sources of fan noise.

  7. New Fan Engine Noise-Reduction Concept Using Trailing Edge Blowing of Fan Blades Demonstrated

    Science.gov (United States)

    Heidelberg, Laurence J.

    2002-01-01

    A major source of noise in commercial turbofan engines is the interaction of the fan blade wakes with the fan exit vanes (stators). These wakes can be greatly reduced by filling them with air blown out of the blade trailing edge. Extensive testing of this concept has demonstrated significant noise reductions. These tests were conducted on a low-speed, 4- ft-diameter fan using hollow blades at NASA Glenn Research Center's Aeroacoustic Propulsion Laboratory (AAPL).

  8. C-5 Reliability Enhancement and Re-engining Program (C-5 RERP)

    Science.gov (United States)

    2015-12-01

    military designation) turbofan engine with increased takeoff thrust, stage-3 noise compliance, and Federal Aviation Regulation pollution compliance. In...to include training, technical orders and the Time Compliance Technical Order (TCTO). The new software fixed a number of nuisance errors and also...Wartime >= 75% Noise Compliance Certifiable under FAR Part 36 Stage 4 noise standards Certifiable under FAR Part 36 Stage 4 noise standards

  9. Thermodynamics of engineered gold binding peptides: establishing the structure-activity relationships.

    Science.gov (United States)

    Seker, Urartu Ozgur Safak; Wilson, Brandon; Kulp, John L; Evans, John S; Tamerler, Candan; Sarikaya, Mehmet

    2014-07-14

    Adsorption behavior of a gold binding peptide was experimentally studied to achieve kinetics and thermodynamics parameters toward understanding of the binding of an engineered peptide onto a solid metal surface. The gold-binding peptide, GBP1, was originally selected using a cell surface display library and contains 14 amino acid residues. In this work, single- and three-repeats of GBP1 were used to assess the effects of two parameters: molecular architecture versus secondary structure on adsorption on to gold substrate. The adsorption measurements were carried out using surface plasmon resonance (SPR) spectroscopy at temperatures ranging from 10 to 55 °C. At all temperatures, two different regimes of peptide adsorption were observed, which, based on the model, correspond to two sets of thermodynamics values. The values of enthalpy, ΔH(ads), and entropy, ΔS(ads), in these two regimes were determined using the van't Hoff approach and Gibbs-Helmholtz relationship. In general, the values of enthalpy for both peptides are negative indicating GBP1 binding to gold is an exothermic phenomenon and that the binding of three repeat gold binding peptide (3l-GBP1) is almost 5 times tighter than that for the single repeat (l-GBP1). More intriguing result is that the entropy of adsorption for the 3l-GBP1 is negative (-43.4 ± 8.5 cal/(mol K)), while that for the l-GBP1 is positive (10.90 ± 1.3 cal/(mol K)). Among a number of factors that synergistically contribute to the decrease of entropy, long-range ordered self-assembly of the 3l-GBP1 on gold surface is the most effective, probably through both peptide-solid and peptide-peptide intermolecular interactions. Additional adsorption experiments were conducted in the presence of 2,2,2-trifluoroethanol (TFE) to determine how the conformational structures of the biomolecules responded to the environmental perturbation. We found that the peptides differ in their conformational responses to the change in solution conditions; while

  10. A review of optimization techniques used in the design of fibre composite structures for civil engineering applications

    International Nuclear Information System (INIS)

    Awad, Ziad K.; Aravinthan, Thiru; Zhuge, Yan; Gonzalez, Felipe

    2012-01-01

    Highlights: → We reviewed existing optimization techniques of fibre composite structures. → Proposed an improved methodology for design optimization. → Comparison showed the MRDO is most suitable. -- Abstract: Fibre composite structures have become the most attractive candidate for civil engineering applications. Fibre reinforced plastic polymer (FRP) composite materials have been used in the rehabilitation and replacement of the old degrading traditional structures or build new structures. However, the lack of design standards for civil infrastructure limits their structural applications. The majority of the existing applications have been designed based on the research and guidelines provided by the fibre composite manufacturers or based on the designer's experience. It has been a tendency that the final structure is generally over-designed. This paper provides a review on the available studies related to the design optimization of fibre composite structures used in civil engineering such as; plate, beam, box beam, sandwich panel, bridge girder, and bridge deck. Various optimization methods are presented and compared. In addition, the importance of using the appropriate optimization technique is discussed. An improved methodology, which considering experimental testing, numerical modelling, and design constrains, is proposed in the paper for design optimization of composite structures.

  11. Computational engineering

    CERN Document Server

    2014-01-01

    The book presents state-of-the-art works in computational engineering. Focus is on mathematical modeling, numerical simulation, experimental validation and visualization in engineering sciences. In particular, the following topics are presented: constitutive models and their implementation into finite element codes, numerical models in nonlinear elasto-dynamics including seismic excitations, multiphase models in structural engineering and multiscale models of materials systems, sensitivity and reliability analysis of engineering structures, the application of scientific computing in urban water management and hydraulic engineering, and the application of genetic algorithms for the registration of laser scanner point clouds.

  12. Engineering yeast consortia for surface-display of complex cellulosome structures

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wilfred [University of Delaware

    2014-03-31

    As our society marches toward a more technologically advanced future, energy and environmental sustainability are some of the most challenging problems we face today. Biomass is one of the most abundant renewable-feedstock for sustainable production of biofuels. However, the main technological obstacle to more widespread uses of this resource is the lack of low-cost technologies to overcome the recalcitrant nature of the cellulosic structure, especially the hydrolysis step on highly ordered celluloses. In this proposal, we successfully engineered several efficient and inexpensive whole-cell biocatalysts in an effort to produce economically compatible and sustainable biofuels, namely cellulosic ethanol. Our approach was to display of a highly efficient cellulolytic enzyme complex, named cellulosome, on the surface of a historical ethanol producer Saccharomyces cerevisiae for the simultaneous and synergistic saccharification and fermentation of cellulose to ethanol. We first demonstrated the feasibility of assembling a mini-cellulosome by incubating E. coli lysates expressing three different cellulases. Resting cells displaying mini-cellulosomes produced 4-fold more ethanol from phosphoric acid-swollen cellulose (PASC) than cultures with only added enzymes. The flexibility to assemble the mini-cellulosome structure was further demonstrated using a synthetic yeast consortium through intracellular complementation. Direct ethanol production from PASC was demonstrated with resting cell cultures. To create a microorganism suitable for a more cost-effective process, called consolidated bioprocessing (CBP), a synthetic consortium capable of displaying mini-cellulosomes on the cell surface via intercellular complementation was created. To further improve the efficiency, a new adaptive strategy of employing anchoring and adaptor scaffoldins to amplify the number of enzymatic subunits was developed, resulting in the creation of an artificial tetravalent cellulosome on the

  13. Metal Foam Analysis: Improving Sandwich Structure Technology for Engine Fan and Propeller Blades

    Science.gov (United States)

    Fedor, Jessica L.

    2004-01-01

    The Life Prediction Branch of the NASA Glenn Research Center is searching for ways to construct aircraft and rotorcraft engine fan and propeller blades that are lighter and less costly. One possible design is to create a sandwich structure composed of two metal faces sheets and a metal foam core. The face sheets would carry the bending loads and the foam core would have to resist the transverse shear loads. Metal foam is ideal because of its low density and energy absorption capabilities, making the structure lighter, yet still stiff. The material chosen for the face sheets and core was 17-4PH stainless steel, which is easy to make and has appealing mechanical properties. This material can be made inexpensively compared to titanium and polymer matrix composites, the two current fan blade alternatives. Initial tests were performed on design models, including vibration and stress analysis. These tests revealed that the design is competitive with existing designs; however, some problems were apparent that must be addressed before it can be implemented in new technology. The foam did not hold up as well as expected under stress. This could be due to a number of issues, but was most likely a result of a large number of pores within the steel that weakened the structure. The brazing between the face sheets and the foam was also identified as a concern. The braze did not hold up well under shear stress causing the foam to break away from the face sheets. My role in this project was to analyze different options for improving the design. I primarily spent my time examining various foam samples, created with different sintering conditions, to see which exhibited the most favorable characteristics for our purpose. Methods of analysis that I employed included examining strut integrity under a microscope, counting the number of cells per inch, measuring the density, testing the microhardness, and testing the strength under compression. Shear testing will also be done to examine

  14. A Virtual Steel Sculpture for Structural Engineering Education: Development and Initial Findings

    Science.gov (United States)

    Dib, Hazar Nicholas; Adamo-Villani, Nicoletta

    2016-01-01

    We describe the development and evaluation of a virtual steel sculpture for engineering education. A good connection design requires the engineer to have a solid understanding of the mechanics and steel behavior. To help students better understand various connection types, many schools have acquired steel sculptures. A steel sculpture is a…

  15. Estimation of lateral attenuation of air-to-ground jet or turbofan aircraft noise in one-third octave bands

    Science.gov (United States)

    1982-11-01

    This Data Item is available as part of the ESDU Sub-series on Noise. The free-field values of one-third octave band lateral attenuation for air-to-ground airplane noise are estimated. Lateral attenuation is defined as the difference between the under-the-flightpath and sideline free-field levels where the propagation distance of the two sound levels is the same. Data are particularly applicable for the estimation of ground noise levels of turbo-fan powered aircraft. The range of applicability includes sideline noise-levels for turbo-fan and jet powered aircraft when the aircraft's elevation angle, relative to an observer at the sideline location, is greater than five degrees, the wind speed is less than 6 meters/sec and there are no temperature inversions. Guidance is given on the procedure that should be used to estimate sideline noise levels.

  16. Engine-integrated solid oxide fuel cells for efficient electrical power generation on aircraft

    Science.gov (United States)

    Waters, Daniel F.; Cadou, Christopher P.

    2015-06-01

    This work investigates the use of engine-integrated catalytic partial oxidation (CPOx) reactors and solid oxide fuel cells (SOFCs) to reduce fuel burn in vehicles with large electrical loads like sensor-laden unmanned air vehicles. Thermodynamic models of SOFCs, CPOx reactors, and three gas turbine (GT) engine types (turbojet, combined exhaust turbofan, separate exhaust turbofan) are developed and checked against relevant data and source material. Fuel efficiency is increased by 4% and 8% in the 50 kW and 90 kW separate exhaust turbofan systems respectively at only modest cost in specific power (8% and 13% reductions respectively). Similar results are achieved in other engine types. An additional benefit of hybridization is the ability to provide more electric power (factors of 3 or more in some cases) than generator-based systems before encountering turbine inlet temperature limits. A sensitivity analysis shows that the most important parameters affecting the system's performance are operating voltage, percent fuel oxidation, and SOFC assembly air flows. Taken together, this study shows that it is possible to create a GT-SOFC hybrid where the GT mitigates balance of plant losses and the SOFC raises overall system efficiency. The result is a synergistic system with better overall performance than stand-alone components.

  17. Tailoring structure and magnetic characteristics of strontium hexaferrite via Al doping engineering

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H.Z.; Hai, Y.N. [State Key Lab of High Power Semiconductor Laser of Changchun University Science and Technology, Changchun University Science and Technology, Changchun 130022 (China); Yao, B., E-mail: binyao@jlu.edu.cn [State Key Lab of Superhard Materials and Department of Physics, Jilin University, Changchun 130023 (China); Xu, Y. [School of Physics, Northeast Normal University, Changchun 130024 (China); Shan, L. [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry and Department of Chemistry, Jilin University, Changchun 130012 (China); Xu, L.; Tang, J.L.; Wang, Q.H. [State Key Lab of High Power Semiconductor Laser of Changchun University Science and Technology, Changchun University Science and Technology, Changchun 130022 (China)

    2017-01-15

    Emerging structure and magnetic properties of Al{sup 3+}-modified SrFe{sub 12}O{sub 19} M-type hexaferrite system (SrAl{sub x}Fe{sub 12−x}O{sub 19}) had been studied in detail via doping engineering. With Al{sup 3+} ion nominal content ranging from 0 to 4 (0≤x≤4), the lattice parameters decrease due to the substitution of Fe{sup 3+} ions by smaller Al{sup 3+} ions, and the magnetization shows a continuous reduction with the increasing of Al content. For the coercivity, its value initially increases, reaching a maximum value of 16,876.9 Oe at x=3, and then reduces with the Al content further increase. When all the Fe{sup 3+} ions (x=4) are replaced by Al{sup 3+} ions, the net magnetic moment will be closed to zero, that will weaken the exchange interaction between Fe{sup 3+} ions, resulting in decrease of coercivity sharply and transformation ferrimagnetism into antiferromagnetism. The mechanism of the improvement of the magnetic properties induced by Al doping is discussed in the present work. - Highlights: • The coercivity reach a maximum value at x=3 in the SrAl{sub x}Fe{sub 12−x}O{sub 19}. • The coercivity of SrFe{sub 12}O{sub 19} increases due to nonmagnetic Al doping. • The saturation magnetization of SrFe{sub 12}O{sub 19} decreases due to nonmagnetic Al doping. • The transformation ferrimagnetism into antiferromagnetism by nonmagnetic Al doping.

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

    Science.gov (United States)

    1977-01-01

    The design, fabrication, and testing of two experimental high bypass geared turbofan engines and propulsion systems for short haul passenger aircraft are described. The aerodynamic and mechanical design of a variable pitch 1.34 pressure ratio fan for the under the wing (UTW) engine are included. The UTW fan was designed to permit rotation of the 18 composite fan blades into the reverse thrust mode of operation through both flat pitch and stall pitch directions.

  19. A Structural Equation Model for Analysis of Factors Associated with the Choice of Engineering Degrees in a Technical University

    Directory of Open Access Journals (Sweden)

    Antonio Hervás

    2013-01-01

    Full Text Available Many different factors are taken into account by students when choosing a degree and university. Some of these are general considerations, such as the quality of the degree course (ratio of available places/places in first choice, cut-off mark, etc., while others are subjective factors (e.g., friends doing the same course. This paper presents a partial multivariate model that considers the weight of the different variables linked to this decision, as identified in the bibliography. We analyzed four samples of first-year students (total n=1790 from different engineering degree courses at the Universitat Politècnica de València (UPV in the 2010-2011 and 2011-2012 academic years. All the students involved in the study had chosen this university and their courses as their first option. The overall effect shows that the structural model adjusts reasonably well to the different engineering courses analyzed. Similarly, the individual models for each engineering degree manage to identify the different effects involved. In the case of the engineering degree based on new technologies (ICT, the statistical effects are much greater and more statistically significant than in the other three branches of engineering considered. Social and individual factors were seen to have more impact on the choice of ICT degrees at the UPV.

  20. In vivo remodeling and structural characterization of fibrin-based tissue-engineered heart valves in the adult sheep model.

    Science.gov (United States)

    Flanagan, Thomas C; Sachweh, Jörg S; Frese, Julia; Schnöring, Heike; Gronloh, Nina; Koch, Sabine; Tolba, Rene H; Schmitz-Rode, Thomas; Jockenhoevel, Stefan

    2009-10-01

    Autologous fibrin-based tissue-engineered heart valves have demonstrated excellent potential as patient-derived valve replacements. The present pilot study aims to evaluate the structure and mechanical durability of fibrin-based heart valves after implantation in a large-animal model (sheep). Tissue-engineered heart valves were molded using a fibrin scaffold and autologous arterial-derived cells before 28 days of mechanical conditioning. Conditioned valves were subsequently implanted in the pulmonary trunk of the same animals from which the cells were harvested. After 3 months in vivo, explanted valve conduits (n = 4) had remained intact and exhibited native tissue consistency, although leaflets demonstrated insufficiency because of tissue contraction. Routine histology showed remarkable tissue development and cell distribution, along with functional blood vessel ingrowth. A confluent monolayer of endothelial cells was present on the valve surface, as evidenced by scanning electron microscopy and positive von Willebrand factor staining. Immunohistochemistry and extracellular matrix (ECM) assay demonstrated complete resorption of the fibrin scaffold and replacement with ECM proteins. Transmission electron microscopy revealed mature collagen formation and viable, active resident tissue cells. The preliminary findings of implanted fibrin-based tissue-engineered heart valves are encouraging, with excellent tissue remodeling and structural durability after 3 months in vivo. The results from this pilot study highlight the potential for construction of completely "autologous" customized tissue-engineered heart valves based on a patient-derived fibrin scaffold.