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Sample records for load limits

  1. Estimating turbine limit load

    NASA Technical Reports Server (NTRS)

    Glassman, Arthur J.

    1993-01-01

    A method for estimating turbine limit-load pressure ratio from turbine map information is presented and demonstrated. It is based on a mean line analysis at the last-rotor exit. The required map information includes choke flow rate at all speeds as well as pressure ratio and efficiency at the onset of choke at design speed. One- and two-stage turbines are analyzed to compare the results with those from a more rigorous off-design flow analysis and to show the sensitivities of the computed limit-load pressure ratios to changes in the key assumptions.

  2. Variable response load limiting device

    NASA Technical Reports Server (NTRS)

    Mcsmith, Dwight D. (Inventor)

    1988-01-01

    An energy absorbing device used as a load limiting member in a structure to control its response to applied loads is described. It functions by utilizing a spool assembly having flanged ends and an interior cavity of sufficiently large diameter to cause it to deform plastically at a prescribed load. In application, the spool is utilized as a pivot point for the legs of an airplane seat. When properly designed and integrated into the seat arrangement the spool will twist about its axis, deforming plastically when the impact load exceeds the spool yield value. Through this deformation, the spool absorbs the kinetic energy of the movement of the seat at a substantially constant rate, thereby controlling the level of loads transmitted to the seat occupant. By proper sizing and collection of materials, it is possible to control load response in a predictable manner.

  3. Load limiting parachute inflation control

    SciTech Connect

    Redmond, J.; Hinnerichs, T.; Parker, G.

    1994-01-01

    Excessive deceleration forces experienced during high speed deployment of parachute systems can cause damage to the payload and the canopy fabric. Conventional reefing lines offer limited relief by temporarily restricting canopy inflation and limiting the peak deceleration load. However, the open-loop control provided by existing reefing devices restrict their use to a specific set of deployment conditions. In this paper, the sensing, processing, and actuation that are characteristic of adaptive structures form the basis of three concepts for active control of parachute inflation. These active control concepts are incorporated into a computer simulation of parachute inflation. Initial investigations indicate that these concepts promise enhanced performance as compared to conventional techniques for a nominal release. Furthermore, the ability of each controller to adapt to off-nominal release conditions is examined.

  4. Force limit specifications vs. design limit loads in vibration testing

    NASA Technical Reports Server (NTRS)

    Chang, K. Y.

    2000-01-01

    The purpose of the work presented herein is to discuss the results of force limit notching during vibration testing with respect to the traditional limit load design criteria. By using a single-degree-of-freedom (SDOF) system approach, this work shows that with an appropriate force specification the notched response due to force limiting will result in loads comparable with the structural design limit criteria.

  5. 14 CFR 29.337 - Limit maneuvering load factor.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Limit maneuvering load factor. 29.337... Limit maneuvering load factor. The rotorcraft must be designed for— (a) A limit maneuvering load factor... load factor not less than 2.0 and any negative limit maneuvering load factor of not less than −0.5 for...

  6. 14 CFR 29.337 - Limit maneuvering load factor.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limit maneuvering load factor. 29.337... Limit maneuvering load factor. The rotorcraft must be designed for— (a) A limit maneuvering load factor... load factor not less than 2.0 and any negative limit maneuvering load factor of not less than −0.5 for...

  7. 14 CFR 23.337 - Limit maneuvering load factors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limit maneuvering load factors. 23.337... Flight Loads § 23.337 Limit maneuvering load factors. (a) The positive limit maneuvering load factor n... airplanes; or (3) 6.0 for acrobatic category airplanes. (b) The negative limit maneuvering load factor may...

  8. 14 CFR 23.337 - Limit maneuvering load factors.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Limit maneuvering load factors. 23.337... Flight Loads § 23.337 Limit maneuvering load factors. (a) The positive limit maneuvering load factor n... airplanes; or (3) 6.0 for acrobatic category airplanes. (b) The negative limit maneuvering load factor may...

  9. Load limiting energy absorbing lightweight debris catcher

    NASA Technical Reports Server (NTRS)

    Kahn, Jon B. (Inventor); Schneider, William C. (Inventor)

    1991-01-01

    In the representative embodiment of the invention disclosed, a load limiting, energy absorbing net is arranged to overlay a normally-covered vent opening in the rear bulkhead of the space orbiter vehicle. Spatially-disposed flexible retainer straps are extended from the net and respectively secured to bulkhead brackets spaced around the vent opening. The intermediate portions of the straps are doubled over and stitched together in a pattern enabling the doubled-over portions to progressively separate at a predicable load designed to be well below the tensile capability of the straps as the stitches are successively torn apart by the forces imposed on the retainer members whenever the cover plate is explosively separated from the bulkhead and propelled into the net. By arranging these stitches to be successively torn away at a load below the strap strength in response to forces acting on the retainers that are less than the combined strength of the retainers, this tearing action serves as a predictable compact energy absorber for safely halting the cover plate as the retainers are extended as the net is deployed. The invention further includes a block of an energy-absorbing material positioned in the net for receiving loose debris produced by the explosive release of the cover plate.

  10. Load-limiting parachute inflation control

    NASA Astrophysics Data System (ADS)

    Redmond, James M.; Hinnerichs, Terry D.; Parker, Gordon G.

    1994-05-01

    Excessive deceleration forces experienced during high speed deployment of parachute systems can cause damage to the payload and the canopy fabric. Conventional reefing lines offer limited relief by temporarily restricting canopy inflation and limiting the peak deceleration load. However, the open-loop control provided by existing reefing devices restrict their use to a specific set of deployment conditions. In this paper, the sensing, processing, and actuation that are characteristic of adaptive structures form the basis of three concepts for active control of parachute inflation. These active control concepts are incorporated into a computer simulation of parachute inflation. Initial investigations indicate that these concepts promise enhanced performance as compared to conventional techniques for a nominal release. Furthermore, the ability of each controller to adapt to off-nominal release conditions is examined.

  11. 14 CFR 23.681 - Limit load static tests.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Limit load static tests. 23.681 Section 23.681 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Control Systems § 23.681 Limit load static tests. (a) Compliance with the limit load requirements of...

  12. 14 CFR 23.681 - Limit load static tests.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Limit load static tests. 23.681 Section 23.681 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Control Systems § 23.681 Limit load static tests. (a) Compliance with the limit load requirements of...

  13. 14 CFR 23.681 - Limit load static tests.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Limit load static tests. 23.681 Section 23.681 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Control Systems § 23.681 Limit load static tests. (a) Compliance with the limit load requirements of...

  14. 14 CFR 23.681 - Limit load static tests.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Limit load static tests. 23.681 Section 23.681 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Control Systems § 23.681 Limit load static tests. (a) Compliance with the limit load requirements of...

  15. 14 CFR 23.681 - Limit load static tests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limit load static tests. 23.681 Section 23.681 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Control Systems § 23.681 Limit load static tests. (a) Compliance with the limit load requirements of...

  16. 14 CFR 29.681 - Limit load static tests.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Limit load static tests. 29.681 Section 29.681 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... load static tests. (a) Compliance with the limit load requirements of this part must be shown by...

  17. 14 CFR 25.681 - Limit load static tests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limit load static tests. 25.681 Section 25.681 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... load static tests. (a) Compliance with the limit load requirements of this Part must be shown by...

  18. 14 CFR 25.681 - Limit load static tests.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Limit load static tests. 25.681 Section 25.681 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... load static tests. (a) Compliance with the limit load requirements of this Part must be shown by...

  19. 14 CFR 29.681 - Limit load static tests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limit load static tests. 29.681 Section 29.681 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... load static tests. (a) Compliance with the limit load requirements of this part must be shown by...

  20. 14 CFR 29.681 - Limit load static tests.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Limit load static tests. 29.681 Section 29.681 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... load static tests. (a) Compliance with the limit load requirements of this part must be shown by...

  1. 14 CFR 29.681 - Limit load static tests.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Limit load static tests. 29.681 Section 29.681 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... load static tests. (a) Compliance with the limit load requirements of this part must be shown by...

  2. 14 CFR 25.681 - Limit load static tests.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Limit load static tests. 25.681 Section 25.681 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... load static tests. (a) Compliance with the limit load requirements of this Part must be shown by...

  3. 14 CFR 25.681 - Limit load static tests.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Limit load static tests. 25.681 Section 25.681 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... load static tests. (a) Compliance with the limit load requirements of this Part must be shown by...

  4. 14 CFR 29.681 - Limit load static tests.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Limit load static tests. 29.681 Section 29.681 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... load static tests. (a) Compliance with the limit load requirements of this part must be shown by...

  5. 14 CFR 25.681 - Limit load static tests.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Limit load static tests. 25.681 Section 25.681 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... load static tests. (a) Compliance with the limit load requirements of this Part must be shown by...

  6. Limit loads for centrally cracked square plates under biaxial tension

    NASA Astrophysics Data System (ADS)

    Graba, Marcin

    2016-12-01

    This paper is concerned with the determination of limit loads for centrally cracked square plates subjected to biaxial tension. It briefly discusses the concept of limit loads and some aspects of numerical modelling. It presents results of numerical calculations conducted for two-dimensional (plane strain state and plane stress state) and three-dimensional cases. It also considers the relationship between the limit load and the crack length, the specimen thickness, the yield strength and the biaxial load factor, defined for the purpose of this work. The paper includes approximation formulae to calculate the limit load.

  7. 14 CFR 29.337 - Limit maneuvering load factor.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 29.337... ranging from a positive limit of 3.5 to a negative limit of −1.0; or (b) Any positive limit...

  8. 14 CFR 27.337 - Limit maneuvering load factor.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 27.337... ranging from a positive limit of 3.5 to a negative limit of −1.0; or (b) Any positive limit...

  9. 14 CFR 29.337 - Limit maneuvering load factor.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 29.337... ranging from a positive limit of 3.5 to a negative limit of −1.0; or (b) Any positive limit...

  10. 14 CFR 27.337 - Limit maneuvering load factor.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 27.337... ranging from a positive limit of 3.5 to a negative limit of −1.0; or (b) Any positive limit...

  11. Structural loads prediction in force-limited vibration testing

    NASA Technical Reports Server (NTRS)

    Chang, K. Y.

    2002-01-01

    The purpose of this paper is to study whether the force limiting has accomplished the notching requirement to limit the equipment structural response in low frequency vibration tests to something less than the design load.

  12. 14 CFR 25.337 - Limit maneuvering load factors.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Conditions § 25.337 Limit maneuvering load factors. (a) Except where limited by maximum (static) lift coefficients, the airplane is assumed to be subjected to symmetrical maneuvers resulting in the...

  13. 14 CFR 25.337 - Limit maneuvering load factors.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Conditions § 25.337 Limit maneuvering load factors. (a) Except where limited by maximum (static) lift coefficients, the airplane is assumed to be subjected to symmetrical maneuvers resulting in the...

  14. 14 CFR 25.337 - Limit maneuvering load factors.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Conditions § 25.337 Limit maneuvering load factors. (a) Except where limited by maximum (static) lift coefficients, the airplane is assumed to be subjected to symmetrical maneuvers resulting in the...

  15. 14 CFR 27.681 - Limit load static tests.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Limit load static tests. 27.681 Section 27.681 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... static tests. (a) Compliance with the limit load requirements of this part must be shown by tests...

  16. 14 CFR 27.681 - Limit load static tests.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Limit load static tests. 27.681 Section 27.681 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... static tests. (a) Compliance with the limit load requirements of this part must be shown by tests...

  17. 14 CFR 27.681 - Limit load static tests.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Limit load static tests. 27.681 Section 27.681 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... static tests. (a) Compliance with the limit load requirements of this part must be shown by tests...

  18. 14 CFR 27.681 - Limit load static tests.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Limit load static tests. 27.681 Section 27.681 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... static tests. (a) Compliance with the limit load requirements of this part must be shown by tests...

  19. 14 CFR 27.681 - Limit load static tests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limit load static tests. 27.681 Section 27.681 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... static tests. (a) Compliance with the limit load requirements of this part must be shown by tests...

  20. 29 CFR 1917.111 - Maintenance and load limits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Maintenance and load limits. 1917.111 Section 1917.111 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) MARINE TERMINALS Terminal Facilities § 1917.111 Maintenance and load limits...

  1. 14 CFR 25.23 - Load distribution limits.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...) Ranges of weights and centers of gravity within which the airplane may be safely operated must be established. If a weight and center of gravity combination is allowable only within certain load distribution... and center of gravity combinations must be established. (b) The load distribution limits may not...

  2. 14 CFR 25.23 - Load distribution limits.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...) Ranges of weights and centers of gravity within which the airplane may be safely operated must be established. If a weight and center of gravity combination is allowable only within certain load distribution... and center of gravity combinations must be established. (b) The load distribution limits may not...

  3. 14 CFR 25.23 - Load distribution limits.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...) Ranges of weights and centers of gravity within which the airplane may be safely operated must be established. If a weight and center of gravity combination is allowable only within certain load distribution... and center of gravity combinations must be established. (b) The load distribution limits may not...

  4. 14 CFR 25.23 - Load distribution limits.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...) Ranges of weights and centers of gravity within which the airplane may be safely operated must be established. If a weight and center of gravity combination is allowable only within certain load distribution... and center of gravity combinations must be established. (b) The load distribution limits may not...

  5. 14 CFR 25.23 - Load distribution limits.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...) Ranges of weights and centers of gravity within which the airplane may be safely operated must be established. If a weight and center of gravity combination is allowable only within certain load distribution... and center of gravity combinations must be established. (b) The load distribution limits may not...

  6. 14 CFR 27.337 - Limit maneuvering load factor.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Limit maneuvering load factor. 27.337 Section 27.337 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 27.337...

  7. 14 CFR 27.337 - Limit maneuvering load factor.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Limit maneuvering load factor. 27.337 Section 27.337 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 27.337...

  8. 14 CFR 27.339 - Resultant limit maneuvering loads.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Resultant limit maneuvering loads. 27.339 Section 27.339 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Flight Loads §...

  9. 14 CFR 27.337 - Limit maneuvering load factor.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limit maneuvering load factor. 27.337 Section 27.337 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Flight Loads §...

  10. 29 CFR 1917.111 - Maintenance and load limits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... elevated above ground level, and pier structures over the water shall be conspicuously posted in all cargo areas. (c) Maximum safe load limits shall not be exceeded. (d) All walking and working surfaces in...

  11. Simple bounds on limit loads by elastic finite element analysis

    SciTech Connect

    Mackenzie, D.; Nadarajah, C.; Shi, J.; Boyle, J.T. . Dept. of Mechanical Engineering)

    1993-02-01

    A method for bounding limit loads by an iterative elastic continuum finite element analysis procedure, referred to as the elastic compensation method, is proposed. A number of sample problems are considered, based on both exact solutions and finite element analysis, and it is concluded that the method may be used to obtain limit-load bounds for pressure vessel design by analysis applications with useful accuracy.

  12. 14 CFR 23.23 - Load distribution limits.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... distribution limits. (a) Ranges of weights and centers of gravity within which the airplane may be safely operated must be established. If a weight and center of gravity combination is allowable only within... established for the corresponding weight and center of gravity combinations. (b) The load distribution limits...

  13. 14 CFR 23.23 - Load distribution limits.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... distribution limits. (a) Ranges of weights and centers of gravity within which the airplane may be safely operated must be established. If a weight and center of gravity combination is allowable only within... established for the corresponding weight and center of gravity combinations. (b) The load distribution limits...

  14. 14 CFR 23.23 - Load distribution limits.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... distribution limits. (a) Ranges of weights and centers of gravity within which the airplane may be safely operated must be established. If a weight and center of gravity combination is allowable only within... established for the corresponding weight and center of gravity combinations. (b) The load distribution limits...

  15. 14 CFR 23.23 - Load distribution limits.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... distribution limits. (a) Ranges of weights and centers of gravity within which the airplane may be safely operated must be established. If a weight and center of gravity combination is allowable only within... established for the corresponding weight and center of gravity combinations. (b) The load distribution limits...

  16. 14 CFR 23.23 - Load distribution limits.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... distribution limits. (a) Ranges of weights and centers of gravity within which the airplane may be safely operated must be established. If a weight and center of gravity combination is allowable only within... established for the corresponding weight and center of gravity combinations. (b) The load distribution limits...

  17. Functional stability limits while holding loads in various positions.

    PubMed

    Holbein, M A; Redfern, M S

    1997-05-01

    Stability of the body during manual material handling is an important issue in the prevention of falls and over-exertion injuries. This research investigated stability limits while standing and holding loads in different positions relative to the body. Theoretically, the stability region is the full base of support defined by the perimeter of the foot contact area. However, the functional stability region may be smaller. The purpose of this study was to locate functional stability limits with respect to the base of support. Fifteen male subjects leaned as far as possible in four directions in the sagittal and frontal planes. Their center of gravity location at these extremes determined the stability limit. The results showed that functional stability limits reached only about 60% of the distance to the maximum base of support limits under the conditions of this study. The sway angles reached at the stability limits averaged 9.2 degrees anteroposteriorly and 15.3 degrees laterally. External load positions which lowered the center of gravity of the body-and-load system extended those stability limits. This study provides a postural stability perspective of load-holding which may be applied in establishing safe lifting and reach limits.

  18. 14 CFR 25.337 - Limit maneuvering load factors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... maneuvering load factors prescribed in this section. Pitching velocities appropriate to the corresponding pull... factor n for any speed up to Vn may not be less than 2.1+24,000/ (W +10,000) except that n may not be... negative limit maneuvering load factor— (1) May not be less than −1.0 at speeds up to V C; and (2) Must...

  19. 14 CFR 25.337 - Limit maneuvering load factors.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... maneuvering load factors prescribed in this section. Pitching velocities appropriate to the corresponding pull... factor n for any speed up to Vn may not be less than 2.1+24,000/ (W +10,000) except that n may not be... negative limit maneuvering load factor— (1) May not be less than −1.0 at speeds up to V C; and (2) Must...

  20. NCAP test improvements with pretensioners and load limiters.

    PubMed

    Walz, Marie

    2004-03-01

    New Car Assessment Program (NCAP) test scores, measured by the United States Department of Transportation's (USDOT) National Highway Traffic Safety Administration (NHTSA), were analyzed in order to assess the benefits of equipping safety belt systems with pretensioners and load limiters. Safety belt pretensioners retract the safety belt almost instantly in a crash to remove excess slack. They tie the occupant to the vehicle's deceleration early during the crash, reducing the peak load experienced by the occupant. Load limiters and other energy management systems allow safety belts to yield in a crash, preventing the shoulder belt from directing too much energy on the chest of the occupant. In NCAP tests, vehicles are crashed into a fixed barrier at 35 mph. During the test, instruments measure the accelerations of the head and chest, as well as the force on the legs of anthropomorphic dummies secured in the vehicle by safety belts. NCAP data from model year 1998 through 2001 cars and light trucks were examined. The combination of pretensioners and load limiters is estimated to reduce Head Injury Criterion (HIC) by 232, chest acceleration by an average of 6.6 g's, and chest deflection (displacement) by 10.6 mm, for drivers and right front passengers. The unit used to measure chest acceleration (g) is defined as a unit of force equal to the force exerted by gravity. All of these reductions are statistically significant. When looked at individually, pretensioners are more effective in reducing HIC scores for both drivers and right front passengers, as well as chest acceleration and chest deflection scores for drivers. Load limiters show greater reductions in chest acceleration and chest deflection scores for right front passengers. By contrast, in make-models for which neither load limiters nor pretensioners have been added, there is little change during 1998 to 2001 in HIC, chest acceleration, or chest deflection values in NCAP tests.

  1. Fatigue life prediction under service load considering strengthening effect of loads below fatigue limit

    NASA Astrophysics Data System (ADS)

    Zhao, Lihui; Zheng, Songlin; Feng, Jinzhi

    2014-11-01

    Lightweight design requires an accurate life prediction for structures and components under service loading histories. However, predicted life with the existing methods seems too conservative in some cases, leading to a heavy structure. Because these methods are established on the basis that load cycles would only cause fatigue damage, ignore the strengthening effect of loads. Based on Palmgren-Miner Rule (PMR), this paper introduces a new method for fatigue life prediction under service loadings by taking into account the strengthening effect of loads below the fatigue limit. In this method, the service loadings are classified into three categories: damaging load, strengthening load and none-effect load, and the process for fatigue life prediction is divided into two stages: stage I and stage II, according to the best strengthening number of cycles. During stage I, fatigue damage is calculated considering both the strengthening and damaging effect of load cycles. While during stage II, only the damaging effect is considered. To validate this method, fatigue lives of automobile half shaft and torsion beam rear axle are calculated based on the new method and traditional methods, such as PMR and Modified Miner Rule (MMR), and fatigue tests of the two components are conducted under service loading histories. The tests results show that the percentage errors of the predicted life with the new method to mean life of tests for the two components are -3.78% and -1.76% separately, much lesser than that with PMR and MMR. By considering the strengthening effect of loads below the fatigue limit, the new method can significantly improve the accuracy for fatigue life prediction. Thus lightweight design can be fully realized in the design stage.

  2. Heat loading limits for solid transuranic wastes storage

    SciTech Connect

    Spatz, T.L.

    1993-07-01

    Heat loading limits have been established for four storage configurations of TRU wastes. The calculations were performed assuming the worst case scenario whereby all the heat generated within a drum was generated within one ``cut`` and that this cut was located in the very center of the drum. Poly-boxes containing one HEPA filter were assumed to have a uniform heat generation throughout the filter. The maximum allowable temperatures were based on the materials in the containers. A comparison between the drum center temperature for a uniform heat load distribution and for the center temperature when the heat load is confined to one cut in the center of the drum is also illustrated. This comparison showed that the heat load of a particular drum can be more than doubled by distributing the sources of heat uniformly throughout the container.

  3. Centaur Standard Shroud (CSS) static limit load structural tests

    NASA Technical Reports Server (NTRS)

    Eastwood, C.

    1975-01-01

    The structural capabilities of the jettisonable metal shroud were tested and the interaction of the shroud with the Centaur stage was evaluated. A flight-configured shroud and the assemblies of the associated Centaur stage were tested for applied axial and shear loads to flight limit values. The tests included various thermal, pressure, and load conditions to verify localized strength capabilities, to evaluate subsystem performance, and to determine the aging effect on insulation system properties. The tests series verified the strength capabilities of the shroud and of all associated flight assembles. Shroud deflections were shown to remain within allowable limits so long as load sharing members were connected between the shroud and the Centaur stage.

  4. Nitrogen critical loads using biodiversity-related critical limits.

    PubMed

    Posch, Maximilian; Aherne, Julian; Hettelingh, Jean-Paul

    2011-10-01

    Critical loads are widely used in the effects-based assessment of emission reduction policies. While the impacts of acidification have diminished, there is increasing concern regarding the effects of nitrogen deposition on terrestrial ecosystems. In this context much attention has been focussed on empirical critical loads as well as simulations with linked geochemistry-vegetation models. Surprisingly little attention has been paid to adapt the widely used simple mass balance approach. This approach has the well-established benefit of easy regional applicability, while incorporating specified critical chemical criteria to protect specified receptors. As plant occurrence/biodiversity is related to both the nutrient and acidity status of an ecosystem, a single abiotic factor (chemical criterion) is not sufficient. Rather than an upper limit for deposition (i.e., critical load), linked nutrient nitrogen and acidity chemical criteria for plant occurrence result in an 'optimal' nitrogen and sulphur deposition envelope. Copyright © 2010 Elsevier Ltd. All rights reserved.

  5. Load-limiting landing gear footpad energy absorption system

    NASA Technical Reports Server (NTRS)

    Hansen, Chris; Tsai, Ted

    1994-01-01

    As a precursor to future manned missions to the moon, an inexpensive, unmanned vehicle that could carry small, scientific payloads to the lunar surface was studied by NASA. The vehicle, called the Common Lunar Lander, required extremely optimized structural systems to increase the potential payload mass. A lightweight energy-absorbing system (LAGFEAS), which also acts as a landing load-limiter was designed to help achieve this optimized structure. Since the versatile and easily tailored system is a load-limiter, it allowed for the structure to be designed independently of the ever-changing landing energy predictions. This paper describes the LAGFEAS system and preliminary verification testing performed at NASA's Johnson Space Center for the Common Lunar Lander program.

  6. Improved Loading of Sulfate-Limited Waste in Glass

    SciTech Connect

    Aloy, A.; Soshnikov, R.; Trofimenko, A.V.; Vienna, J.D.; Elliott, M.L.; Holtzscheiter, E.W.

    2006-07-01

    The allowable sulfate concentration limits waste loading in borosilicate glasses (e.g., Hanford low-activity waste [LAW] and Idaho National Laboratory sodium-bearing waste. By the Hanford baseline formulation method, the tolerated amount of sulfate in LAW is 0.77 wt% (as SO{sub 3}) at the lowest soda contents, decreasing to 0.35 wt% at the highest soda contents. Roughly half of the Hanford LAW (on a glass mass basis) will be limited by sulfate tolerance of the glass melt. If the allowable concentrations of sulfate were to be increased only moderately, the cost and time required to vitrify the Hanford LAW would be significantly reduced A series of high-sulfate glass formulations were developed by Khlopin Radium Institute (Russian Federation) and Pacific Northwest National Laboratory. These glasses were tested at crucible, small melter, and larger test melter scales for not only sulfate retention but key product quality criteria as well. The key properties of the glasses to be disposed of at Hanford were measured (product consistency test and vapor hydration test), and processing-related properties (viscosity and electrical conductivity) were predicted using property composition models. The results for 28 glass compositions tested at crucible-scale, 6 glass compositions tested at small-melter-scale, and 4 glass compositions tested at larger melter scale are presented in this paper. The melter tests were all performed with waste composition and processing parameters (e.g., bubbling rate, melting rate, temperature) prototypic for the Hanford LAW melter design. The results show that sulfate loadings as high as 1.5 wt% with soda concentrations as high as 20 wt% are viable with improved formulation methods. These results suggest that the loading of sulfate-limited Hanford LAW may be increased by over 300%, relative to the current formulation. However, additional work is recommended before implementing the new formulations. (authors)

  7. Improved Loading of Sulfate-Limited Waste in Glass

    SciTech Connect

    Aloy, A. S.; Soshnikov, R. A.; Trofimenko, A. V.; Vienna, John D.; Elliott, Michael L.; Holtzscheiter, Earl W.

    2006-02-28

    The loading of many wastes in borosilicate glass are limited by the allowable sulfate concentration (e.g., Hanford low-activity waste [LAW] and Idaho National Laboratory [INL] sodium-bearing waste [SBW]). By the Hanford baseline formulation method, the tolerated amount of sulfate in LAW is 0.77 wt% (as SO3) at the lowest soda contents, decreasing to 0.35 wt% at the highest soda contents. Roughly half of the Hanford LAW (on a glass mass basis) will be limited by sulfate tolerance of the glass melt. If the allowable concentrations of sulfate were to be increased only moderately, the cost and time required to vitrify the Hanford LAW would be significantly reduced.

  8. 78 FR 28896 - Design Limits and Loading Combinations for Metal Primary Reactor Containment System Components

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-16

    ... COMMISSION Design Limits and Loading Combinations for Metal Primary Reactor Containment System Components... Combinations for Metal Primary Reactor Containment System Components,'' in which there are no substantive... loading combinations for metal primary reactor containment system components. ADDRESSES: Please refer...

  9. 76 FR 25648 - Special Conditions: Gulfstream Model GVI Airplane; Limit Engine Torque Loads for Sudden Engine...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-05

    ... Federal Aviation Administration 14 CFR Part 25 Special Conditions: Gulfstream Model GVI Airplane; Limit..., the engine mounts and the supporting structures must be designed to withstand a ``limit engine torque load imposed by sudden engine stoppage due to malfunction or structural failure.'' Limit loads are...

  10. A Simplistic Look at Limit Stresses from Random Loading

    NASA Technical Reports Server (NTRS)

    Lee, H. M.

    1993-01-01

    Utilizing a continuous beam model, this report compares the potential stresses imposed on the beam from a random environment with those resulting from a typical static load analysis or test simulation. The Miles' equation used to develop peak response accelerations is shown to become a force equation in the hands of strength assessment personnel. This may prove to be unrealistic since hardware dynamic stresses are related to deflection rather than load. Correlation of the stress state for any static analysis or test with the actual dynamic response stress is strictly dependent upon how well the static deflections simulate the predominant dynamic mode shape. The report proposes that the general shape of this predominant mode, along with the peak response accelerations of major masses be used in strength assessments. From these data, a tailored enforced displacement loading may prove to be more effective in reproducing random induced stresses on flight hardware.

  11. Static test induced loads verification beyond elastic limit

    NASA Technical Reports Server (NTRS)

    Verderaime, V.; Harrington, F.

    1996-01-01

    Increasing demands for reliable and least-cost high-performance aerostructures are pressing design analyses, materials, and manufacturing processes to new and narrowly experienced performance and verification technologies. This study assessed the adequacy of current experimental verification of the traditional binding ultimate safety factor which covers rare events in which no statistical design data exist. Because large high-performance structures are inherently very flexible, boundary rotations and deflections under externally applied loads approaching fracture may distort their transmission and unknowingly accept submarginal structures or prematurely fracturing reliable ones. A technique was developed, using measured strains from back-to-back surface mounted gauges, to analyze, define, and monitor induced moments and plane forces through progressive material changes from total-elastic to total-inelastic zones within the structural element cross section. Deviations from specified test loads are identified by the consecutively changing ratios of moment-to-axial load.

  12. Static test induced loads verification beyond elastic limit

    NASA Technical Reports Server (NTRS)

    Verderaime, V.; Harrington, F.

    1996-01-01

    Increasing demands for reliable and least-cost high performance aerostructures are pressing design analyses, materials, and manufacturing processes to new and narrowly experienced performance and verification technologies. This study assessed the adequacy of current experimental verification of the traditional binding ultimate safety factor which covers rare events in which no statistical design data exist. Because large, high-performance structures are inherently very flexible, boundary rotations and deflections under externally applied loads approaching fracture may distort their transmission and unknowingly accept submarginal structures or prematurely fracturing reliable ones. A technique was developed, using measured strains from back-to-back surface mounted gauges, to analyze, define, and monitor induced moments and plane forces through progressive material changes from total-elastic to total inelastic zones within the structural element cross section. Deviations from specified test loads are identified by the consecutively changing ratios of moment-to-axial load.

  13. 14 CFR 29.339 - Resultant limit maneuvering loads.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... factors are assumed to act at the center of each rotor hub and at each auxiliary lifting surface, and to act in directions and with distributions of load among the rotors and auxiliary lifting surfaces, so as to represent each critical maneuvering condition, including power-on and power-off flight with the...

  14. 14 CFR 29.339 - Resultant limit maneuvering loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... factors are assumed to act at the center of each rotor hub and at each auxiliary lifting surface, and to act in directions and with distributions of load among the rotors and auxiliary lifting surfaces, so as to represent each critical maneuvering condition, including power-on and power-off flight with the...

  15. 14 CFR 29.339 - Resultant limit maneuvering loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... factors are assumed to act at the center of each rotor hub and at each auxiliary lifting surface, and to act in directions and with distributions of load among the rotors and auxiliary lifting surfaces, so as to represent each critical maneuvering condition, including power-on and power-off flight with the...

  16. 14 CFR 29.339 - Resultant limit maneuvering loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... factors are assumed to act at the center of each rotor hub and at each auxiliary lifting surface, and to act in directions and with distributions of load among the rotors and auxiliary lifting surfaces, so as to represent each critical maneuvering condition, including power-on and power-off flight with the...

  17. 14 CFR 29.339 - Resultant limit maneuvering loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... factors are assumed to act at the center of each rotor hub and at each auxiliary lifting surface, and to act in directions and with distributions of load among the rotors and auxiliary lifting surfaces, so as to represent each critical maneuvering condition, including power-on and power-off flight with the...

  18. Limit Load and Buckling Analysis for Assessing Hanford Single-Shell Tank Dome Structural Integrity - 12278

    SciTech Connect

    Johnson, Ken I.; Deibler, John E.; Karri, Naveen K.; Pilli, Siva P.; Julyk, Larry J.

    2012-07-01

    The U.S. Department of Energy, Office of River Protection has commissioned a structural analysis of record for the Hanford single shell tanks to assess their structural integrity. The analysis used finite element techniques to predict the tank response to the historical thermal and operating loads. The analysis also addressed the potential tank response to a postulated design basis earthquake. The combined response to static and seismic loads was then evaluated against the design requirements of American Concrete Institute standard, ACI-349-06, for nuclear safety-related concrete structures. Further analysis was conducted to estimate the plastic limit load and the elastic-plastic buckling capacity of the tanks. The limit load and buckling analyses estimate the margin between the applied loads and the limiting load capacities of the tank structure. The potential for additional dome loads from waste retrieval equipment and the addition of large dome penetrations to accommodate retrieval equipment has generated additional interest in the limit load and buckling analyses. This paper summarizes the structural analysis methods that were used to evaluate the limit load and buckling of the single shell tanks. This paper summarizes the structural analysis methods that were used to evaluate the limit load and buckling limit states of the underground single shell tanks at the Hanford site. The limit loads were calculated using nonlinear finite element models that capture the progressive deformation and damage to the concrete as it approaches the limit load. Both uniform and concentrated loads over the tank dome were considered, and the analysis shows how adding a penetration in the center of the tank would affect the limit loads. For uniform surface loads, the penetration does not affect the limit load because concrete crushing and rebar yielding initiates first at the top of the wall, away from the penetration. For concentrated loads, crushing initiates at the center of the

  19. Limiting performance of ground transportation vehicles subject to transient loading

    NASA Technical Reports Server (NTRS)

    Pilkey, W. D.; Wang, B. P.

    1974-01-01

    A computational approach to determining the limiting performance of vehicles subject to transient disturbances based on response variable criteria is set forth. For the purposes of a limiting performance study, the transportation system dynamics are described using second- or first-order equations in which the sought for quantity is a vector of time-varying functions called control or isolator forces that have replaced portions of the physical system. Computations are performed as a linear programming problem. As an example of the limiting performance of vehicles in protecting passengers or cargo under crash conditions, the problem of lading damage of a rail vehicle that is struck by another vehicle is considered.

  20. Immediate-loading post extractive implants: indications, advantages and limits.

    PubMed

    Mampieri, G; Ottria, L; Barlattani, A

    2008-07-01

    The possibility of rehabilitating immediately an edentulous patient offers today remarkable advantages because it satisfies the patient's demands for comfort, aesthetics, and functionality and reduces the surgical stages for the professional.In the last years clinicians and companies have been concentrating their efforts in the development of new surgical techniques and biomaterials in order to speed up the osteointegration process, which fosters the functionality, that is the immediate-loading.This clinical report, based on the analysis of the literature and on the presentation of a case report, shows how satisfying results in functionality and aesthetic can be obtained by a careful diagnosis and an accurate therapeutic planning, reducing at the same time the stress for the patient and the surgical stages for the professional.In any case, it is necessary to have the rehabilitations with immediate-loaded implants directed by workers with a good knowledge and experience in surgery, periodontology, and prosthesis or by a work team able to face all the complications such advanced rehabilitations may cause.

  1. Calculation Method for Flight Limit Load of V-band Clamp Separation Shock

    NASA Astrophysics Data System (ADS)

    Iwasa, Takashi; Shi, Qinzhong

    A simplified calculation method for estimating a flight limit load of the V-band clamp separation shock was established. With this method, the flight limit load is estimated through addition of an appropriate envelope margin to the results acquired with the simplified analysis method proposed in our previous paper. The envelope margin used in the method was calculated based on the reviews on the differences observed between the results of a pyroshock test and the analysis. Using the derived envelope margin, a calculating formula of the flight limit load, which envelopes the actual pyroshock responses with a certain probability, was developed. Based on the formula, flight limit loads for several actual satellites were estimated and compared to the test results. The comparative results showed that the estimated flight limit loads appropriately envelope the test results, which confirmed the effectiveness of the proposed method.

  2. Rankine cycle load limiting through use of a recuperator bypass

    DOEpatents

    Ernst, Timothy C.

    2011-08-16

    A system for converting heat from an engine into work includes a boiler coupled to a heat source for transferring heat to a working fluid, a turbine that transforms the heat into work, a condenser that transforms the working fluid into liquid, a recuperator with one flow path that routes working fluid from the turbine to the condenser, and another flow path that routes liquid working fluid from the condenser to the boiler, the recuperator being configured to transfer heat to the liquid working fluid, and a bypass valve in parallel with the second flow path. The bypass valve is movable between a closed position, permitting flow through the second flow path and an opened position, under high engine load conditions, bypassing the second flow path.

  3. Methods for combining payload parameter variations with input environment. [calculating design limit loads compatible with probabilistic structural design criteria

    NASA Technical Reports Server (NTRS)

    Merchant, D. H.

    1976-01-01

    Methods are presented for calculating design limit loads compatible with probabilistic structural design criteria. The approach is based on the concept that the desired limit load, defined as the largest load occurring in a mission, is a random variable having a specific probability distribution which may be determined from extreme-value theory. The design limit load, defined as a particular of this random limit load, is the value conventionally used in structural design. Methods are presented for determining the limit load probability distributions from both time-domain and frequency-domain dynamic load simulations. Numerical demonstrations of the method are also presented.

  4. An Analytical Means for Determination of Scoring Limited Load Capacity in Sliding/Rolling Contact

    DTIC Science & Technology

    1979-12-01

    Scoring limited load capacity of paired discs in sliding/rolling lubricated contact is addressed. The approach used previously acquired data in a multiple regression analysis. The resulting mathematical expression for load capacity at failure has a correlation coefficient greater than 99%.

  5. 78 FR 79074 - Technical Report Evaluating Seat Belt Pretensioners and Load Limiters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-27

    ... National Highway Traffic Safety Administration Technical Report Evaluating Seat Belt Pretensioners and Load...). ACTION: Request for comments on technical report. SUMMARY: This notice announces NHTSA's publication of a technical report evaluating the effectiveness of pretensioners and load limiters for seat belts in the...

  6. Plastic Limit Load Analysis of Cylindrical Pressure Vessels with Different Nozzle Inclination

    NASA Astrophysics Data System (ADS)

    Prakash, Anupam; Raval, Harit Kishorchandra; Gandhi, Anish; Pawar, Dipak Bapu

    2016-04-01

    Sudden change in geometry of pressure vessel due to nozzle cutout, leads to local stress concentration and deformation, decreasing its strength. Elastic plastic analysis of cylindrical pressure vessels with different inclination angles of nozzle is important to estimate plastic limit load. In the present study, cylindrical pressure vessels with combined inclination of nozzles (i.e. in longitudinal and radial plane) are considered for elastic plastic limit load analysis. Three dimensional static nonlinear finite element analyses of cylindrical pressure vessels with nozzle are performed for incremental pressure loading. The von Mises stress distribution on pressure vessel shows higher stress zones at shell-nozzle junction. Approximate plastic limit load is obtained by twice elastic slope method. Variation in limit pressure with different combined inclination angle of nozzle is analyzed and found to be distinct in nature. Reported results can be helpful in optimizing pressure vessel design.

  7. Competition explains limited attention and perceptual resources: implications for perceptual load and dilution theories

    PubMed Central

    Scalf, Paige E.; Torralbo, Ana; Tapia, Evelina; Beck, Diane M.

    2013-01-01

    Both perceptual load theory and dilution theory purport to explain when and why task-irrelevant information, or so-called distractors are processed. Central to both explanations is the notion of limited resources, although the theories differ in the precise way in which those limitations affect distractor processing. We have recently proposed a neurally plausible explanation of limited resources in which neural competition among stimuli hinders their representation in the brain. This view of limited capacity can also explain distractor processing, whereby the competitive interactions and bias imposed to resolve the competition determine the extent to which a distractor is processed. This idea is compatible with aspects of both perceptual load and dilution models of distractor processing, but also serves to highlight their differences. Here we review the evidence in favor of a biased competition view of limited resources and relate these ideas to both classic perceptual load theory and dilution theory. PMID:23717289

  8. A platform for actively loading cargo RNA to elucidate limiting steps in EV-mediated delivery

    PubMed Central

    Hung, Michelle E.; Leonard, Joshua N.

    2016-01-01

    Extracellular vesicles (EVs) mediate intercellular communication through transfer of RNA and protein between cells. Thus, understanding how cargo molecules are loaded and delivered by EVs is of central importance for elucidating the biological roles of EVs and developing EV-based therapeutics. While some motifs modulating the loading of biomolecular cargo into EVs have been elucidated, the general rules governing cargo loading and delivery remain poorly understood. To investigate how general biophysical properties impact loading and delivery of RNA by EVs, we developed a platform for actively loading engineered cargo RNAs into EVs. In our system, the MS2 bacteriophage coat protein was fused to EV-associated proteins, and the cognate MS2 stem loop was engineered into cargo RNAs. Using this Targeted and Modular EV Loading (TAMEL) approach, we identified a configuration that substantially enhanced cargo RNA loading (up to 6-fold) into EVs. When applied to vesicles expressing the vesicular stomatitis virus glycoprotein (VSVG) – gesicles – we observed a 40-fold enrichment in cargo RNA loading. While active loading of mRNA-length (>1.5 kb) cargo molecules was possible, active loading was much more efficient for smaller (~0.5 kb) RNA molecules. We next leveraged the TAMEL platform to elucidate the limiting steps in EV-mediated delivery of mRNA and protein to prostate cancer cells, as a model system. Overall, most cargo was rapidly degraded in recipient cells, despite high EV-loading efficiencies and substantial EV uptake by recipient cells. While gesicles were efficiently internalized via a VSVG-mediated mechanism, most cargo molecules were rapidly degraded. Thus, in this model system, inefficient endosomal fusion or escape likely represents a limiting barrier to EV-mediated transfer. Altogether, the TAMEL platform enabled a comparative analysis elucidating a key opportunity for enhancing EV-mediated delivery to prostate cancer cells, and this technology should be of

  9. Forming Limits in Sheet Metal Forming for Non-Proportional Loading Conditions - Experimental and Theoretical Approach

    SciTech Connect

    Ofenheimer, Aldo; Buchmayr, Bruno; Kolleck, Ralf

    2005-08-05

    The influence of strain paths (loading history) on material formability is well known in sheet forming processes. Sophisticated experimental methods are used to determine the entire shape of strain paths of forming limits for aluminum AA6016-T4 alloy. Forming limits for sheet metal in as-received condition as well as for different pre-deformation are presented. A theoretical approach based on Arrieux's intrinsic Forming Limit Stress Curve (FLSC) concept is employed to numerically predict the influence of loading history on forming severity. The detailed experimental strain paths are used in the theoretical study instead of any linear or bilinear simplified loading histories to demonstrate the predictive quality of forming limits in the state of stress.

  10. Loading Path Dependence of Forming Limit Diagram of a TRIP800 Steel

    SciTech Connect

    Choi, Kyoo Sil; Soulami, Ayoub; Liu, Wenning N.; Sun, Xin; Khaleel, Mohammad A.

    2011-04-12

    In this paper, the microstructure-based finite element modeling method is used in investigating the loading path dependence of formability of transformation induced plasticity (TRIP) steels. For this purpose, the effects of different loading path on the forming limit diagrams (FLD) of TRIP steels are qualitatively examined using the representative volume element (RVE) of a commercial TRIP800 steel. First, the modeling method was introduced, where a combined isotropic/kinematic hardening rule is adopted for the constituent phases in order to rightly describe the cyclic deformation behaviors of TRIP steels during the forming process with combined loading paths which may include the unloading between the two consecutive loadings. Material parameters for the constituent phases remained the same as those in the authors’ previous study [1] except for some adjustments for the martensite phase due to the introduction of the new combined hardening rule. Based on the new material parameters and new hardening rule, the predicted deformation behaviors of the TRIP800 steel show quite similar qualitative trends to those reported in other experimental works. Pseudo-forming limit strain diagrams (Pseudo-FLD) for the TRIP800 steel were, then, obtained for various loading paths. The computational results show that, similar to other single phase materials, the TRIP800 steel shows very sensitive loading path dependence in the strain-based forming limit diagrams (strain-FLD), but does not in the stress-based forming limit diagrams (stress-FLD), and that the phase transformation does not have significant effects on the FLD for the TRIP800 steel. From the observations in this study, the current modeling methods can be used in examining the qualitative trends of FLD of TRIP steels under different loading paths/prestrains.

  11. Effect of crash pulse shape on seat stroke requirements for limiting loads on occupants of aircraft

    NASA Technical Reports Server (NTRS)

    Carden, Huey D.

    1992-01-01

    An analytical study was made to provide comparative information on various crash pulse shapes that potentially could be used to test seats under conditions included in Federal Regulations Part 23 Paragraph 23.562(b)(1) for dynamic testing of general aviation seats, show the effects that crash pulse shape can have on the seat stroke requirements necessary to maintain a specified limit loading on the seat/occupant during crash pulse loadings, compare results from certain analytical model pulses with approximations of actual crash pulses, and compare analytical seat results with experimental airplace crash data. Structural and seat/occupant displacement equations in terms of the maximum deceleration, velocity change, limit seat pan load, and pulse time for five potentially useful pulse shapes were derived; from these, analytical seat stroke data were obtained for conditions as specified in Federal Regulations Part 23 Paragraph 23.562(b)(1) for dynamic testing of general aviation seats.

  12. 76 FR 44245 - Special Conditions: Gulfstream Model GVI Airplane; Limit Engine Torque Loads for Sudden Engine...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-25

    ...-new, two- engine jet transport airplane with an executive cabin interior. The maximum takeoff weight..., Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue, SW., Renton, Washington... Administration 14 CFR Part 25 Special Conditions: Gulfstream Model GVI Airplane; Limit Engine Torque Loads...

  13. 76 FR 8778 - Construction Standards on Posting Emergency Telephone Numbers and Floor Load Limits; Extension of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-15

    ... Floor Load Limits; Extension of the Office of Management and Budget's (OMB) Approval of Information... extend OMB approval of the information collection requirements specified by the Construction Standards on... for the Information Collection Request (ICR) (OSHA-2011- 0032). All comments, including any personal...

  14. A simple method of calculating lower-bound limit loads for axisymmetric thin shells

    SciTech Connect

    Boyle, J.T.; Hamilton, R.; Shi, J.; Mackenzie, D.

    1997-05-01

    In this paper, a simple method for calculating lower-bound limit loads for shells is presented, based on Ilyushin`s and Ivanov`s generalized yield criterion, respectively, and using the elastic compensation procedure. Several examples, including torispherical and conical ends, radial nozzles, and a skirted vessel, are examined using this method. The results are compared with previously published results.

  15. Critical acid load limits in a changing climate: implications and solutions

    Treesearch

    Steven G. McNulty

    2010-01-01

    The federal agencies of the United States are currently developing guidelines for critical nitrogen load limits for U.S. forest ecosystems. These guidelines will be used to develop regulations designed to maintain pollutant inputs below the level shown to damage specified ecosystems.

  16. Manual lifting load limit equation for adult Indian women workers based on physiological criteria.

    PubMed

    Maiti, Rina; Ray, G G

    2004-01-15

    A comprehensive equation for the evaluation of a maximum load limit for manual load lifting has been developed for the first time for Indian adult female workers, based on a physiological criterion due to the limitation of applicability of the NIOSH (1991) equation. Ten adult female workers, who had been engaged in building construction activities for at least 7 years participated in this study. The cut-off value was selected as the working heart rate corresponding to the 33% level of maximum aerobic power (i.e. V'O2 max.) of this population, which was equivalent to a heart rate of 101.6 beats x min(-1). An equation was developed based on the effects of the following three lifting parameters on working heart rate: vertical height (knee, waist, shoulder and maximum reach height), lifting frequency (1, 4, 7 and 14 lifts x min(-1)), and load weight (5, 10 and 15 kg). The variations of the specific lifting parameter values were selected from field observations. From this equation, the maximum load limit was calculated as 15.4 kg and the workers give this a psychophysical rating as in the moderate to heavy category.

  17. Limitations of power conversion systems under transient loads and impact on the pulsed tokamak power reactor

    NASA Astrophysics Data System (ADS)

    Sager, G. T.; Wong, C. P. C.; Kapich, D. D.; McDonald, C. F.; Schleicher, R. W.

    1993-11-01

    The impact of cyclic loading of the power conversion system of a helium-cooled, pulsed tokamak power plant is assessed. Design limits of key components of heat transport systems employing Rankine and Brayton thermodynamic cycles are quantified based on experience in gas-cooled fission reactor design and operation. Cyclic loads due to pulsed tokamak operation are estimated. Expected performance of the steam generator is shown to be incompatible with pulsed tokamak operation without load leveling thermal energy storage. The close cycle gas turbine is evaluated qualitatively based on performance of existing industrial and aeroderivative gas turbines. Advances in key technologies which significantly improve prospects for operation with tokamak fusion plants are reviewed.

  18. Limitations of power conversion systems under transient loads and impact on the pulsed tokamak power reactor

    SciTech Connect

    Sager, G.T.; Wong, C.P.C.; Kapich, D.D.; McDonald, C.F.; Schleicher, R.W.

    1993-11-01

    The impact of cyclic loading of the power conversion system of a helium-cooled, pulsed tokamak power plant is assessed. Design limits of key components of heat transport systems employing Rankie and Brayton thermodynamic cycles are quantified based on experience in gas-cooled fission reactor design and operation. Cyclic loads due to pulsed tokamak operation are estimated. Expected performance of the steam generator is shown to be incompatible with pulsed tokamak operation without load leveling thermal energy storage. The close cycle gas turbine is evaluated qualitatively based on performance of existing industrial and aeroderivative gas turbines. Advances in key technologies which significantly improve prospects for operation with tokamak fusion plants are reviewed.

  19. Simulations of ITER start-up and assessment of limiter power loads

    NASA Astrophysics Data System (ADS)

    Federici, G.; Zolotukhin, O.; Kobayashi, M.; Loarte, A.; Strohmayer, G.; Tanga, A.; Portone, A.; Horton, L.; Feng, Y.; Sardei, F.; Gribov, Y.; Shimada, M.; Polevoi, A.; Mitteau, R.; Lowry, C.

    2007-06-01

    This paper presents the results of a modelling study conducted to estimate the power crossing the separatrix (PSOL) in the ITER device during a standard start-up sequence. This is used to calculate the power intercepted by the start-up limiters and the resulting power load distribution. The models and methodologies applied to calculate PSOL and the power loads on the limiters are described in detail elsewhere ([e.g., M. Kobayashi et al., Nucl. Fusion. 47 (2) (2007) 61]) and only a brief mention of some of the main results is included here. These assessments show that for the range of conditions analysed, the maximum PSOL intercepted by the two ITER limiter start-up modules during the current ramp-phase is ∼6 MW. The peak power load to each limiter is calculated to be ∼5 MW/m2, but these values depends on assumptions on physical quantities (e.g., transport coefficients, i.e., D⊥ and χ⊥), which are uncertain and still await confirmation by experiments. Recommendations are made for modelling and experiments to extend the study presented here.

  20. Predicting Deformation Limits of Dual-Phase Steels Under Complex Loading Paths

    DOE PAGES

    Cheng, G.; Choi, K. S.; Hu, X.; ...

    2017-04-05

    Here in this study, the deformation limits of various DP980 steels are examined with the deformation instability theory. Under uniaxial tension, overall stress–strain curves of the material are estimated based on a simple rule of mixture (ROM) with both iso-strain and iso-stress assumptions. Under complex loading paths, an actual microstructure-based finite element (FE) method is used to resolve the deformation compatibilities explicitly between the soft ferrite and hard martensite phases. The results show that, for uniaxial tension, the deformation instability theory with iso-strain-based ROM can be used to provide the lower bound estimate of the uniform elongation (UE) for themore » various DP980 considered. Under complex loading paths, the deformation instability theory with microstructure-based FE method can be used in examining the effects of various microstructural features on the deformation limits of DP980 steels.« less

  1. Face-specific capacity limits under perceptual load do not depend on holistic processing.

    PubMed

    Thoma, Volker

    2014-12-01

    Previous observations that face recognition may proceed automatically, without drawing on attentional resources, have been challenged by recent demonstrations that only a few faces can be processed at one time. However, a question remains about the nature of the stimulus properties that underlie face-specific capacity limits. Two experiments showed that speeded categorization of a famous face (such as a politician or pop star) is facilitated when it is congruent with a peripheral distractor face. This congruency effect is eliminated if the visual search is loaded with more than one face, unlike previous demonstrations of speeded classification using semantic information. Importantly, congruency effects are also eliminated when the search task is loaded with nontarget faces that are shown in an inverted orientation. These results indicate that face-specific capacity limits are not determined by the configural ("holistic") properties of face recognition.

  2. Effects of specimen size on limiting compressive loading for silicate, ceramic, and other materials

    SciTech Connect

    Okhrimenko, G.M.

    1995-06-01

    Published data are examined on the ultimate strength in uniaxial compression for glass, glass ceramics, porcelain, crystalline silicon, periclase - spinel - chromite material PSCM, and ferrite in relation to the specimen dimensions. Two methods are proposed for combined experimental and computational estimation of the effects from the volume on the limiting load, which are based only on the data obtained from testing specimens with one or two standard dimensions.

  3. UK catchment nutrient loads 1993-2003, a new approach using harmonised monitoring scheme data: temporal changes, geographical distribution, limiting nutrients and loads to coastal waters.

    PubMed

    Earl, Timothy J; Upton, Graham J G; Nedwell, David B

    2014-07-01

    The work provides robust estimates of nutrient loads (nitrate and phosphate) from all UK catchments: as required by the Water Framework Directive to monitor catchments' health, and to inform management of these environments. To calculate nutrient loads, data for nutrient concentrations and water flow are combined. In the UK, flow data are typically available at hourly intervals at more than 1300 gauging stations but concentration data are collected less frequently (roughly weekly) and at fewer locations (about 280). The sparseness of the concentration data limits the occasions for which load can be calculated, so a mathematical model was derived which was used to interpolate the concentrations between measurements. The model's parameters provide useful information about the annual nutrient concentration cycles within any catchment, and permitted improved estimates of both the annual loads of N and P, and of the N : P ratios, from mainland UK catchments. Data from 1993-2003 showed nitrate loads from UK catchments were generally constant, while orthophosphate loads generally declined. N : P ratios suggested that most catchments in the north and west of the UK were potentially P-limited although a few were potentially N-limited, while many in central and eastern UK oscillated seasonally between N and P limitation. Knowledge of the nutrient which is potentially limiting to biological productivity is a key factor for management of a catchment's nutrient loads. Calculations of nutrient export loads to coastal regions showed that UK catchments contributed only about 16.5% of total fluvial loads of nitrate to the North Sea, or about 3% of the total N loads when inputs from the Atlantic were included. Orthophosphate loads from the UK catchments into the North Sea were only 1.7% of the total P inputs from rivers and the Atlantic but did not include riverine inputs of P adsorbed to particles.

  4. Advances in developing HIV-1 viral load assays for resource-limited settings.

    PubMed

    Wang, ShuQi; Xu, Feng; Demirci, Utkan

    2010-01-01

    Commercial HIV-1 RNA viral load assays have been routinely used in developed countries to monitor antiretroviral treatment (ART). However, these assays require expensive equipment and reagents, well-trained operators, and established laboratory infrastructure. These requirements restrict their use in resource-limited settings where people are most afflicted with the HIV-1 epidemic. Inexpensive alternatives such as the Ultrasensitive p24 assay, the reverse transcriptase (RT) assay and in-house reverse transcription quantitative polymerase chain reaction (RT-qPCR) have been developed. However, they are still time-consuming, technologically complex and inappropriate for decentralized laboratories as point-of-care (POC) tests. Recent advances in microfluidics and nanotechnology offer new strategies to develop low-cost, rapid, robust and simple HIV-1 viral load monitoring systems. We review state-of-the-art technologies used for HIV-1 viral load monitoring in both developed and developing settings. Emerging approaches based on microfluidics and nanotechnology, which have potential to be integrated into POC HIV-1 viral load assays, are also discussed. Copyright © 2010 Elsevier Inc. All rights reserved.

  5. Advances in Developing HIV-1 Viral Load Assays for Resource-Limited Settings

    PubMed Central

    Wang, ShuQi; Xu, Feng; Demirci, Utkan

    2010-01-01

    Commercial HIV-1 RNA viral load assays have been routinely used in developed countries to monitor antiretroviral treatment (ART). However, these assays require expensive equipment and reagents, well-trained operators, and established laboratory infrastructure. These requirements restrict their use in resource-limited settings where people are most afflicted with the HIV-1 epidemic. Inexpensive alternatives such as the Ultrasensitive p24 assay, the Reverse Transcriptase (RT) assay and in-house reverse transcription quantitative polymerase chain reaction (RT-qPCR) have been developed. However, they are still time-consuming, technologically complex and inappropriate for decentralized laboratories as point-of-care (POC) tests. Recent advances in microfluidics and nanotechnology offer new strategies to develop low-cost, rapid, robust and simple HIV-1 viral load monitoring systems. We review state-of-the-art technologies used for HIV-1 viral load monitoring in both developed and developing settings. Emerging approaches based on microfluidics and nanotechnology, which have potential to be integrated into POC HIV-1 viral load assays, are also discussed. PMID:20600784

  6. Limiter heat loads during the first operation of the W7-X stellarator

    NASA Astrophysics Data System (ADS)

    Wurden, Glen; Niemann, Holger; Jakubowski, Marcin; Bozhenkov, Sergey; Biedermann, Christoph; Marsen, Stefan; Effenberg, Florian; Stephey, Laurie; Schmitz, Oliver; W7-X Team

    2016-10-01

    During the first operational phase (OP1.1) of the new W7-X stellarator, five poloidal graphite limiters served as the main boundary for the plasma. There was a dedicated set of diagnostics to observe the performance of the temporary poloidal limiters and infer basic transport behavior of the 3-D helical SOL plasma. We describe IR imaging of the limiters, which resulted in observations of 1) heat flux determination as a function of time and space, 2) total energy into the limiters, 3) high-frequency helical patterns of energy bursts onto the limiters, 4) changes in surface emissivity, and 5) detection of UFO's (small-to-large dusts). These measurements were made in 2 magnetic configuration discharges (differing iota), and in ones where the power loads to the limiters were systematically modified by the use of trim coils. Observed power fractions on the limiters ranged from 40% to 20% of the 0.6 to 4 MW ECRH input powers. Acknowledgement: Funded under DOE LANS Contract DE-AC5026NA25396 and DE-SC0014210, and within the EUROfusion Consortium under Euratom Grant 633053.

  7. Force Limited Vibration Testing: Computation C2 for Real Load and Probabilistic Source

    NASA Astrophysics Data System (ADS)

    Wijker, J. J.; de Boer, A.; Ellenbroek, M. H. M.

    2014-06-01

    To prevent over-testing of the test-item during random vibration testing Scharton proposed and discussed the force limited random vibration testing (FLVT) in a number of publications, in which the factor C2 is besides the random vibration specification, the total mass and the turnover frequency of the load(test item), a very important parameter. A number of computational methods to estimate C2 are described in the literature, i.e. the simple and the complex two degrees of freedom system, STDFS and CTDFS, respectively. Both the STDFS and the CTDFS describe in a very reduced (simplified) manner the load and the source (adjacent structure to test item transferring the excitation forces, i.e. spacecraft supporting an instrument).The motivation of this work is to establish a method for the computation of a realistic value of C2 to perform a representative random vibration test based on force limitation, when the adjacent structure (source) description is more or less unknown. Marchand formulated a conservative estimation of C2 based on maximum modal effective mass and damping of the test item (load) , when no description of the supporting structure (source) is available [13].Marchand discussed the formal description of getting C 2 , using the maximum PSD of the acceleration and maximum PSD of the force, both at the interface between load and source, in combination with the apparent mass and total mass of the the load. This method is very convenient to compute the factor C 2 . However, finite element models are needed to compute the spectra of the PSD of both the acceleration and force at the interface between load and source.Stevens presented the coupled systems modal approach (CSMA), where simplified asparagus patch models (parallel-oscillator representation) of load and source are connected, consisting of modal effective masses and the spring stiffnesses associated with the natural frequencies. When the random acceleration vibration specification is given the CMSA

  8. Sparking limits, cavity loading, and beam breakup instability associated with high-current rf linacs

    SciTech Connect

    Faehl, R.J.; Lemons, D.S.; Thode, L.E.

    1982-01-01

    The limitations on high-current rf linacs due to gap sparking, cavity loading, and the beam breakup instability are studied. It appears possible to achieve cavity accelerating gradients as high as 35 MV/m without sparking. Furthermore, a linear analysis, as well as self-consistent particle simulations of a multipulsed 10 kA beam, indicated that only a negligible small fraction of energy is radiated into nonfundamental cavity modes. Finally, the beam breakup instability is analyzed and found to be able to magnify initial radial perturbations by a factor of no more than about 20 during the beam transit time through a 1 GeV accelerator.

  9. Strip-loaded slot waveguide: a step beyond integrated photonics limits (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Roussey, Matthieu; Ahmadi, Leila; Pélisset, Ségolène; Häyrinen, Markus; Bera, Arijit; Kontturi, Ville; Laukkanen, Janne; Vartiainen, Ismo; Honkanen, Seppo; Svirko, Yuri P.; Kuittinen, Markku

    2017-02-01

    We propose a novel waveguide type based on the concept of strip-loaded waveguide. A strip-loaded waveguide is composed of a thin-film slab waveguide allowing a vertical confinement of the electromagnetic field. A lower refractive index strip provides the lateral confinement by inducing a slight modification of the effective index in the slab. By using such a generic device we will demonstrate how the limits of integrated photonics can be extended, especially, in terms of propagation losses while adding complex structure on the waveguide. Since light sees only a slight variation of effective index, and not an abrupt change of material, propagation losses of the device are fully determined by the film rather than by the structuration. Different micro- and nano-structures will be presented through simulation and experimental results. We will focus especially on the study of Y-junctions, ring resonators, interferometers, and Bragg gratings. Another advantage of strip-loaded waveguides is the simplicity of fabrication. In order to fabricate the devices we employed nano-imprinting of polymer, a fabrication technique suitable for mass production. The low refractive index of the polymer allows a large panel of materials for the slab waveguide, e.g., silicon, titanium dioxide, and lithium niobate. This diversity in the choice of the materials gives to the platform the potential to operate on a wide wavelength range from UV to IR, for multiple applications in telecommunications, sensing and bio-sensing, and medical devices.

  10. Effects of Hypotonic Saline Loading in Hydrated Dog: Evidence for a Saline-induced Limit on Distal Tubular Sodium Transport*

    PubMed Central

    Stein, Richard M.; Abramson, Ruth G.; Kahn, Thomas; Levitt, Marvin F.

    1967-01-01

    We performed studies on dogs under hydrated conditions, utilizing the rate of free water formation (CH2O) as an index of the rate of distal tubular sodium transport. Since CH2O could be progressively increased with no evidence of a maximal rate during loading with hypotonic (2.5%) mannitol, it was concluded that there is no limit on distal tubular sodium transport during mannitol loading. In contrast, during hypotonic (0.45%) saline loading CH2O rose initially, but as urine flow (V) exceeded 25% of the filtered load CH2O attained maximal levels (up to 20% of the filtered load) and remained stable as V increased to 50% of the filtered load. It was concluded that saline loading progressively inhibits proximal sodium reabsorption. Initially, the distal tubule absorbes a large fraction of the proximal rejectate and sodium excretion rises slightly. Eventually, an alteration in distal sodium transport appears which culminates in a maximal rate or transport limit. This distal transport limit provoked by saline loading could not be characterized by a classical Tm as seen with glucose and does not seem to be consequent to high rates of flow through the distal tubule. Regardless of the precise nature of this limit, the major increment in sodium excretion develops during saline loading only after saline alters the capacity of the distal tubule to transport sodium. PMID:6027084

  11. Behaviour of Silicon-Doped CFC Limiter under High Heat Load in TEXTOR-94

    NASA Astrophysics Data System (ADS)

    Huber, A.; Philipps, V.; Hirai, T.; Kirschner, A.; Lehnen, M.; Pospieszczyk, A.; Schweer, B.; Sergienko, G.

    In order to study the impurity production, recycling and power deposition a Si doped CFC test limiter (NS31) was used in TEXTOR-94. The release of impurities (C, Si, O, Cr, CD radicals) was measured spectroscopically. A reduced methane production was found in the Si doped graphite when compared to a pure graphite limiter. A smaller decrease of the carbon fluxes could also be observed. The limiter contained about 1%-1.5% of Si, but a relative Si flux (Si/D) from the Si doped CFC surface between 0.12% and 0.4% has been measured. A chemical erosion of Si due to formation of SiDx has not been observed. Silicon evaporated from the surface at temperatures above 1500°C. This led to an increase of Si concentration and total radiation losses from the plasma. Surface analysis shows the formation of microcracks and holes on the plasma exposed limiter surface. The released Si was deposited in the vicinity of the tangency point of the limiter. Whereas a Si depletion was observed in the area of highest power loading with values reaching in and in-between fibres values of 0.03% and 0.02% respectively.

  12. Modeling of limiter heat loads and impurity transport in Wendelstein 7-X startup plasmas

    NASA Astrophysics Data System (ADS)

    Effenberg, Florian; Feng, Y.; Frerichs, H.; Schmitz, O.; Hoelbe, H.; Koenig, R.; Krychowiak, M.; Pedersen, T. S.; Bozhenkov, S.; Reiter, D.

    2015-11-01

    The quasi-isodynamic stellarator Wendelstein 7-X starts plasma operation in a limiter configuration. The field consists of closed magnetic flux surfaces avoiding magnetic islands in the plasma boundary. Because of the small size of the limiters and the absence of wall-protecting elements in this phase, limiter heat loads and impurity generation due to plasma surface interaction become a concern. These issues are studied with the 3D fluid plasma edge and kinetic neutral transport code EMC3-Eirene. It is shown that the 3D SOL consists of three separate helical magnetic flux bundles of different field line connection lengths. A density scan at input power of 4MW reveals a strong modulation of the plasma paramters with the connection length. The limiter peak heat fluxes drop from 14 MWm-2 down to 10 MWm-2 with raising the density from 1 ×1018m-3 to 1.9 ×1019m-3, accompanied by an increase of the heat flux channel widths λq. Radiative power losses can help to avoid thermal overloads of the limiters at the upper margin of the heating power. The power removal feasibility of the intrinsic carbon and other extrinsic light impurities via active gas injection is discussed as a preparation of this method for island divertor operation. Work supported in part by start up funds of the Department of Engineering Physics at the University of Wisconsin - Madison, USA and by the U.S. Department of Energy under grant DE-SC0013911.

  13. Developments in CD4 and Viral Load Monitoring in Resource-Limited Settings

    PubMed Central

    Rowley, Christopher F.

    2014-01-01

    CD4 counts and human immunodeficiency virus (HIV) load testing are essential components of HIV care, and making these tests available in resource-limited settings is critical to the roll-out of HIV treatment globally. Until recently, the evidence supporting the importance of laboratory monitoring in resource-limited settings was lacking, but there is now a consensus emerging that testing should become routine to ensure the longevity of treatment programs. Low-cost, point-of-care testing offers the potential to fill this role as it potentially improves all aspects of HIV care, ranging from the diagnosis and staging of HIV infection in both infants and adults to monitoring for treatment failure once antiretroviral therapy has been initiated. It is imperative for low-cost solutions to become a reality, but it is equally imperative that close scrutiny be given to each new device that hits the market to ensure they perform optimally in all settings. PMID:24218101

  14. Developments in CD4 and viral load monitoring in resource-limited settings.

    PubMed

    Rowley, Christopher F

    2014-02-01

    CD4 counts and human immunodeficiency virus (HIV) load testing are essential components of HIV care, and making these tests available in resource-limited settings is critical to the roll-out of HIV treatment globally. Until recently, the evidence supporting the importance of laboratory monitoring in resource-limited settings was lacking, but there is now a consensus emerging that testing should become routine to ensure the longevity of treatment programs. Low-cost, point-of-care testing offers the potential to fill this role as it potentially improves all aspects of HIV care, ranging from the diagnosis and staging of HIV infection in both infants and adults to monitoring for treatment failure once antiretroviral therapy has been initiated. It is imperative for low-cost solutions to become a reality, but it is equally imperative that close scrutiny be given to each new device that hits the market to ensure they perform optimally in all settings.

  15. Use of Adaptive Injection Strategies to Increase the Full Load Limit of RCCI Operation

    SciTech Connect

    Hanson, Reed; Ickes, Andrew; Wallner, Thomas

    2015-01-01

    Dual-fuel combustion using port-injection of low reactivity fuel combined with direct injection of a higher reactivity fuel, otherwise known as Reactivity Controlled Compression Ignition (RCCI), has been shown as a method to achieve low-temperature combustion with moderate peak pressure rise rates, low engine-out soot and NOx emissions, and high indicated thermal efficiency. A key requirement for extending to high-load operation is moderating the reactivity of the premixed charge prior to the diesel injection. One way to accomplish this is to use a very low reactivity fuel such as natural gas. In this work, experimental testing was conducted on a 13L multi-cylinder heavy-duty diesel engine modified to operate using RCCI combustion with port injection of natural gas and direct injection of diesel fuel. Engine testing was conducted at an engine speed of 1200 RPM over a wide variety of loads and injection conditions. The impact on dual-fuel engine performance and emissions with respect to varying the fuel injection parameters is quantified within this study. The injection strategies used in the work were found to affect the combustion process in similar ways to both conventional diesel combustion and RCCI combustion for phasing control and emissions performance. As the load is increased, the port fuel injection quantity was reduced to keep peak cylinder pressure and maximum pressure rise rate under the imposed limits. Overall, the peak load using the new injection strategy was shown to reach 22 bar BMEP with a peak brake thermal efficiency of 47.6%.

  16. Use of Adaptive Injection Strategies to Increase the Full Load Limit of RCCI Operation

    SciTech Connect

    Hanson, Reed; Ickes, Andrew; Wallner, Thomas

    2016-04-12

    Dual-fuel combustion using port-injection of low reactivity fuel combined with direct injection (DI) of a higher reactivity fuel, otherwise known as reactivity controlled compression ignition (RCCI), has been shown as a method to achieve low-temperature combustion with moderate peak pressure rise rates, low engine-out soot and NOx emissions, and high indicated thermal efficiency. A key requirement for extending to high-load operation is moderating the reactivity of the premixed charge prior to the diesel injection. One way to accomplish this is to use a very low reactivity fuel such as natural gas. In this work, experimental testing was conducted on a 13 l multicylinder heavy-duty diesel engine modified to operate using RCCI combustion with port injection of natural gas and DI of diesel fuel. Engine testing was conducted at an engine speed of 1200 rpm over a wide variety of loads and injection conditions. The impact on dual-fuel engine performance and emissions with respect to varying the fuel injection parameters is quantified within this study. The injection strategies used in the work were found to affect the combustion process in similar ways to both conventional diesel combustion (CDC) and RCCI combustion for phasing control and emissions performance. As the load is increased, the port fuel injection (PFI) quantity was reduced to keep peak cylinder pressure (PCP) and maximum pressure rise rate (MPRR) under the imposed limits. Overall, the peak load using the new injection strategy was shown to reach 22 bar brake mean effective pressure (BMEP) with a peak brake thermal efficiency (BTE) of 47.6%.

  17. Monitoring HIV Viral Load in Resource Limited Settings: Still a Matter of Debate?

    PubMed Central

    Arnedo, Mireia; Alonso, Elena; Eisenberg, Nell; Ibáñez, Laura; Ferreyra, Cecilia; Jaén, Angels; Flevaud, Laurence; Khamadi, Samuel; Roddy, Paul; Gatell, Jose Maria; Dalmau, David

    2012-01-01

    Introduction Consequences of lack of viral monitoring in predicting the effects of development of HIV drug resistance mutations during HAART in resource-limited settings (RLS) is still a matter of debate. Design To assess, among HIV+ patients receiving their first-line HAART, prevalence of virological failure and genotypic resistance mutations pattern in a Médécins Sans Frontières/Ministry of Health programme in Busia District (Kenya). Methods Patients with HAART treatment for ≥12 months were eligible for the study and those with HIV-RNA ≥5000 copies/ml underwent genotypic study. Total HIV-1 RNA from Dried Blood Spots was extracted using Nuclisens method. Results 926 patients were included. Among 274 (29.6%) patients with detectable viral load, 55 (5.9%) experienced treatment failure (viral load >5.000 copies/ml); 61.8% were female and 10 (18.2%) had clinical failure. Median CD4 cell count was 116 cell/mm3 (IQR: 54–189). Median HIV-RNA was 32,000 copies/ml (IQR: 11000–68000). Eighteen out of 55 (33%) samples could be sequenced on PR and RT genes, with resistance associated mutations (RAMs) in 15 out of 18 samples (83%). Among patients carrying RAMs, 12/15 (81%) harboured RAMs associated to thymidine analogues (TAMs). All of them (100%) showed M184V resistance associated mutation to lamivudine as well as NNRTI's RAMS. Conclusions Virological failure rate in resource-limited settings are similar to those observed in developed countries. Resistance mutation patterns were concordant with HAART received by failing patients. Long term detectable viral load confers greater probability of developing resistance and as a consequence, making difficult to find out a cost-effective subsequent treatment regimen. PMID:23236346

  18. Acute caffeine ingestion's increase of voluntarily chosen resistance-training load after limited sleep.

    PubMed

    Cook, Christian; Beaven, C Martyn; Kilduff, Liam P; Drawer, Scott

    2012-06-01

    This study aimed to determine whether caffeine ingestion would increase the workload voluntarily chosen by athletes in a limited-sleep state. In a double-blind, crossover study, 16 professional rugby players ingested either a placebo or 4 mg/kg caffeine 1 hr before exercise. Athletes classified themselves into nondeprived (8 hr+) or sleep-deprived states (6 hr or less). Exercise comprised 4 sets of bench press, squats, and bent rows at 85% 1-repetition maximum. Athletes were asked to perform as many repetitions on each set as possible without failure. Saliva was collected before administration of placebo or caffeine and again before and immediately after exercise and assayed for testosterone and cortisol. Sleep deprivation produced a very large decrease in total load (p = 1.98 × 10(-7)). Caffeine ingestion in the nondeprived state resulted in a moderate increase in total load, with a larger effect in the sleep-deprived state, resulting in total load similar to those observed in the nondeprived placebo condition. Eight of the 16 athletes were identified as caffeine responders. Baseline testosterone was higher (p < .05) and cortisol trended lower in non-sleep-deprived athletes. Changes in hormones from predose to preexercise correlated to individual workload responses to caffeine. Testosterone response to exercise increased with caffeine compared with placebo, as did cortisol response. Caffeine increased voluntary workload in professional athletes, even more so under conditions of self-reported limited sleep. Caffeine may prove worthwhile when athletes are tired, especially in those identified as responders.

  19. Etching-limiting process and origin of loading effects in silicon etching with hydrogen chloride gas

    NASA Astrophysics Data System (ADS)

    Morioka, Naoya; Suda, Jun; Kimoto, Tsunenobu

    2014-01-01

    The etching-limiting step in slow Si etching with HCl/H2 at atmospheric pressure was investigated. The etching was performed at a low etching rate below 10 nm/min in the temperature range of 1000-1100 °C. In the case of bare Si etching, it was confirmed that the etching rate showed little temperature dependence and was proportional to the equilibrium pressure of the etching by-product SiCl2 calculated by thermochemical analysis. In addition, the etching rates of Si(100) and (110) faces were almost the same. These results indicate that SiCl2 diffusion in the gas phase is the rate-limiting step. In the etching of the Si surface with SiO2 mask patterns, a strong loading effect (mask/opening pattern dependence of the etching rate) was observed. The simulation of the diffusion of gas species immediately above the Si surface revealed that the loading effect was attributed to the pattern-dependent diffusion of SiCl2.

  20. 76 FR 10213 - Special Conditions: Embraer Model EMB-135BJ (Legacy 650) Airplanes, Limit Engine Torque Loads for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-24

    ... appropriate design standards. The latest generation of jet engines is capable of producing, during failure... 650) Airplanes, Limit Engine Torque Loads for Sudden Engine Stoppage AGENCY: Federal Aviation... engine size and the potential torque load imposed by sudden engine-stoppage conditions. The applicable...

  1. Characterization of Engine Control Authority on HCCI Combustion as the High Load Limit is Approached

    SciTech Connect

    Szybist, James P; Edwards, Kevin Dean; Foster, Matthew; Confer, Keith; Moore, Wayne

    2013-01-01

    While the potential emissions and efficiency benefits of homogeneous charge compression ignition (HCCI) combustion are well known, realizing the potentials on a production intent engine presents numerous challenges. In this study we focus on characterizing the authority of the available engine controls as the high load limit of HCCI combustion is approached. The experimental work is performed on a boosted single-cylinder research engine equipped with direct injection (DI) fueling, cooled external exhaust gas recirculation (EGR), and a hydraulic valve actuation (HVA) valve train to enable the negative valve overlap (NVO) breathing strategy. Valve lift and duration are held constant while phasing is varied in an effort to make the results as relevant as possible to production intent cam-based variable valve actuation (VVA) systems on multi-cylinder engines. Results presented include engine loads from 350 to 650 kPa IMEPnet and manifold pressure from 98 to 190 kPaa at 2000 rpm. It is found that in order to increase engine load to 650 kPa IMEPnet, it is necessary to increase manifold pressure and external EGR while reducing the NVO duration. Both NVO duration and fuel injection timing are effective means of controlling combustion phasing, with NVO duration being a coarse control and fuel injection timing being a fine control. NOX emissions are low throughout the study, with emissions below 0.1 g/kW-h at all boosted HCCI conditions, while good combustion efficiency is maintained (>96.5%). Net indicated thermal efficiency increases with load up to 600 kPa IMEPnet, where a peak efficiency of 41% is achieved. Results of independent parametric investigations are presented on the effect of external EGR, intake effect of manifold pressure, and the effect of NVO duration. It is found that increasing EGR at a constant manifold pressure and increasing manifold pressure at a constant EGR rate both have the effect of retarding combustion phasing. It is also found that combustion

  2. Wind, waves, and wing loading: morphological specialization may limit range expansion of endangered albatrosses.

    PubMed

    Suryan, Robert M; Anderson, David J; Shaffer, Scott A; Roby, Daniel D; Tremblay, Yann; Costa, Daniel P; Sievert, Paul R; Sato, Fumio; Ozaki, Kiyoaki; Balogh, Gregory R; Nakamura, Noboru

    2008-01-01

    Among the varied adaptations for avian flight, the morphological traits allowing large-bodied albatrosses to capitalize on wind and wave energy for efficient long-distance flight are unparalleled. Consequently, the biogeographic distribution of most albatrosses is limited to the windiest oceanic regions on earth; however, exceptions exist. Species breeding in the North and Central Pacific Ocean (Phoebastria spp.) inhabit regions of lower wind speed and wave height than southern hemisphere genera, and have large intrageneric variation in body size and aerodynamic performance. Here, we test the hypothesis that regional wind and wave regimes explain observed differences in Phoebastria albatross morphology and we compare their aerodynamic performance to representatives from the other three genera of this globally distributed avian family. In the North and Central Pacific, two species (short-tailed P. albatrus and waved P. irrorata) are markedly larger, yet have the smallest breeding ranges near highly productive coastal upwelling systems. Short-tailed albatrosses, however, have 60% higher wing loading (weight per area of lift) compared to waved albatrosses. Indeed, calculated aerodynamic performance of waved albatrosses, the only tropical albatross species, is more similar to those of their smaller congeners (black-footed P. nigripes and Laysan P. immutabilis), which have relatively low wing loading and much larger foraging ranges that include central oceanic gyres of relatively low productivity. Globally, the aerodynamic performance of short-tailed and waved albatrosses are most anomalous for their body sizes, yet consistent with wind regimes within their breeding season foraging ranges. Our results are the first to integrate global wind and wave patterns with albatross aerodynamics, thereby identifying morphological specialization that may explain limited breeding ranges of two endangered albatross species. These results are further relevant to understanding past and

  3. Wind, waves, and wing loading: Morphological specialization may limit range expansion of endangered albatrosses

    USGS Publications Warehouse

    Suryan, R.M.; Anderson, D.J.; Shaffer, S.A.; Roby, D.D.; Tremblay, Y.; Costa, D.P.; Sievert, P.R.; Sato, F.; Ozaki, K.; Balogh, G.R.; Nakamura, N.

    2008-01-01

    Among the varied adaptations for avian flight, the morphological traits allowing large-bodied albatrosses to capitalize on wind and wave energy for efficient long-distance flight are unparalleled. Consequently, the biogeographic distribution of most albatrosses is limited to the windiest oceanic regions on earth; however, exceptions exist. Species breeding in the North and Central Pacific Ocean (Phoebastria spp.) inhabit regions of lower wind speed and wave height than southern hemisphere genera, and have large intrageneric variation in body size and aerodynamic performance. Here, we test the hypothesis that regional wind and wave regimes explain observed differences in Phoebastria albatross morphology and we compare their aerodynamic performance to representatives from the other three genera of this globally distributed avian family. In the North and Central Pacific, two species (short-tailed P. albatrus and waved P. irrorata) are markedly larger, yet have the smallest breeding ranges near highly productive coastal upwelling systems. Short-tailed albatrosses, however, have 60% higher wing loading (weight per area of lift) compared to waved albatrosses. Indeed, calculated aerodynamic performance of waved albatrosses, the only tropical albatross species, is more similar to those of their smaller congeners (black-footed P. nigripes and Laysan P. immutabilis), which have relatively low wing loading and much larger foraging ranges that include central oceanic gyres of relatively low productivity. Globally, the aerodynamic performance of short-tailed and waved albatrosses are most anomalous for their body sizes, yet consistent with wind regimes within their breeding season foraging ranges. Our results are the first to integrate global wind and wave patterns with albatross aerodynamics, thereby identifying morphological specialization that may explain limited breeding ranges of two endangered albatross species. These results are further relevant to understanding past and

  4. Wind, Waves, and Wing Loading: Morphological Specialization May Limit Range Expansion of Endangered Albatrosses

    PubMed Central

    Suryan, Robert M.; Anderson, David J.; Shaffer, Scott A.; Roby, Daniel D.; Tremblay, Yann; Costa, Daniel P.; Sievert, Paul R.; Sato, Fumio; Ozaki, Kiyoaki; Balogh, Gregory R.; Nakamura, Noboru

    2008-01-01

    Among the varied adaptations for avian flight, the morphological traits allowing large-bodied albatrosses to capitalize on wind and wave energy for efficient long-distance flight are unparalleled. Consequently, the biogeographic distribution of most albatrosses is limited to the windiest oceanic regions on earth; however, exceptions exist. Species breeding in the North and Central Pacific Ocean (Phoebastria spp.) inhabit regions of lower wind speed and wave height than southern hemisphere genera, and have large intrageneric variation in body size and aerodynamic performance. Here, we test the hypothesis that regional wind and wave regimes explain observed differences in Phoebastria albatross morphology and we compare their aerodynamic performance to representatives from the other three genera of this globally distributed avian family. In the North and Central Pacific, two species (short-tailed P. albatrus and waved P. irrorata) are markedly larger, yet have the smallest breeding ranges near highly productive coastal upwelling systems. Short-tailed albatrosses, however, have 60% higher wing loading (weight per area of lift) compared to waved albatrosses. Indeed, calculated aerodynamic performance of waved albatrosses, the only tropical albatross species, is more similar to those of their smaller congeners (black-footed P. nigripes and Laysan P. immutabilis), which have relatively low wing loading and much larger foraging ranges that include central oceanic gyres of relatively low productivity. Globally, the aerodynamic performance of short-tailed and waved albatrosses are most anomalous for their body sizes, yet consistent with wind regimes within their breeding season foraging ranges. Our results are the first to integrate global wind and wave patterns with albatross aerodynamics, thereby identifying morphological specialization that may explain limited breeding ranges of two endangered albatross species. These results are further relevant to understanding past and

  5. Full-scale crash-test evaluation of two load-limiting subfloors for general aviation airframes

    NASA Technical Reports Server (NTRS)

    Carden, H. D.

    1984-01-01

    Three six place, low wing, twin engine general aviation airplane test specimens were crash tested at the Langley Impact Dynamics Research Facility under controlled free flight conditions. One structurally unmodified airplane was the base line specimen for the test series. The other two airplanes were structurally modified to incorporate load limiting (energy absorbing) subfloor concepts into the structure for full scale crash test evaluation and for comparison with the unmodified airplane test results. Typically, the lowest floor accelerations, the lowest anthropomorphic dummy responses, and the least seat crushing of standard and load limiting seats occurred in the airplanes modified with load limiting subfloors, wherein the greatest structural crushing of the subfloor took place. The better performing of the two load limiting subfloor concepts reduced the peak airplane floor accelerations to -25g to -30g as compared with approximately -40g to -55g for the unmodified airplane structure.

  6. Performance of two load-limiting subfloor concepts in full-scale general aviation airplane crash tests

    NASA Technical Reports Server (NTRS)

    Carden, H. D.

    1984-01-01

    Three six-place, low wing, twin-engine general aviation airplane test specimens were crash tested at the langley Impact Dynamics research Facility under controlled free-flight conditions. One structurally unmodified airplane was the baseline airplane specimen for the test series. The other airplanes were structurally modified to incorporate load-limiting (energy-absorbing) subfloor concepts into the structure for full scale crash test evaluation and comparison to the unmodified airplane test results. Typically, the lowest floor accelerations and anthropomorphic dummy occupant responses, and the least seat crushing of standard and load-limiting seats, occurred in the modified load-limiting subfloor airplanes wherein the greatest structural crushing of the subfloor took place. The better performing of the two load-limiting subfloor concepts reduced the peak airplane floor accelerations at the pilot and four seat/occupant locations to -25 to -30 g's as compared to approximately -50 to -55 g's acceleration magnitude for the unmodified airplane structure.

  7. HCCI Load Expansion Opportunities Using a Fully Variable HVA Research Engine to Guide Developments of a Production Intent Cam-Based VVA Engine: The Low Load Limit

    SciTech Connect

    Weall, Adam J; Szybist, James P; Edwards, Kevin Dean; Foster, Matthew; Confer, Keith; Moore, Wayne

    2012-01-01

    While the potential emissions and efficiency benefits of HCCI combustion are well known, realizing the potentials on a production intent engine presents numerous challenges. In this study we focus on identifying challenges and opportunities associated with a production intent cam-based variable valve actuation (VVA) system on a multi-cylinder engine in comparison to a fully flexible, naturally aspirated, hydraulic valve actuation (HVA) system on a single-cylinder engine, with both platforms sharing the same GDI fueling system and engine geometry. The multi-cylinder production intent VVA system uses a 2-step cam technology with wide authority cam phasing, allowing adjustments to be made to the negative valve overlap (NVO) duration but not the valve opening durations. On the single cylinder HVA engine, the valve opening duration and lift are variable in addition to the NVO duration. The content of this paper is limited to the low-medium operating load region at 2000rpm. Using different injection strategies, including the NVO pilot injection approach, the single-cylinder engine is operated over a load range from 160-390 kPa net IMEP at 2000 rpm. Changes to valve opening duration on the single-cylinder HVA engine illustrate opportunities for load expansion and efficiency improvement at certain conditions. For instance, the low load limit can be extended on the HVA engine by reducing breathing and operating closer to a stoichiometric air fuel ratio (AFR) by using valve deactivation. The naturally aspirated engine used here without external EGR confirmed that as operating load increases the emissions of NOx increases due to combustion temperature. NOx emissions are found to be one limitation to the maximum load limitation, the other being high pressure rise rate. It is found that the configuration of the production intent cam-based system represents a good compromise between valve lift and duration in the low to medium load region. Changing the extent of charge motion

  8. HCCI Load Expansion Opportunities using a Fully Variable HVA Research Engine to Guide Development of a Production Intent Cam-based VVA Engine: The Low Load Limit

    SciTech Connect

    Weall, Adam J; Szybist, James P; Edwards, Kevin Dean; Foster, Matthew; Confer, Keith; Moore, Wayne

    2012-01-01

    While the potential emissions and efficiency benefits of HCCI combustion are well known, realizing the potentials on a production intent engine presents numerous challenges. In this study we focus on identifying challenges and opportunities associated with a production intent cam-based variable valve actuation (VVA) system on a multi-cylinder engine in comparison to a fully flexible, naturally aspirated, hydraulic valve actuation (HVA) system on a single-cylinder engine, with both platforms sharing the same GDI fueling system and engine geometry. The multi-cylinder production intent VVA system uses a 2-step cam technology with wide authority cam phasing, allowing adjustments to be made to the negative valve overlap (NVO) duration but not the valve opening durations. On the single cylinder HVA engine, the valve opening duration and lift are variable in addition to the NVO duration. The content of this paper is limited to the low-medium operating load region at 2000rpm. Using different injection strategies, including the NVO pilot injection approach, the single-cylinder engine is operated over a load range from 160-390 kPa net IMEP at 2000 rpm. Changes to valve opening duration on the single-cylinder HVA engine illustrate opportunities for load expansion and efficiency improvement at certain conditions. For instance, the low load limit can be extended on the HVA engine by reducing breathing and operating closer to a stoichiometric air fuel ratio (AFR) by using valve deactivation. The naturally aspirated engine used here without external EGR confirmed that as operating load increases the emissions of NOx increases due to combustion temperature. NOx emissions are found to be one limitation to the maximum load limitation, the other being high pressure rise rate. It is found that the configuration of the production intent cam-based system represents a good compromise between valve lift and duration in the low to medium load region. Changing the extent of charge motion

  9. Strength Estimation of Self-Piercing Rivets using Lower Bound Limit Load Analysis

    SciTech Connect

    Sun, Xin; Khaleel, Mohammad A.

    2005-08-01

    This paper summarizes the authors' work on strength and failure mode estimation of self-piercing rivets (SPR) for automotive applications. First, the static cross tension strength of an SPR joint is estimated using a lower bound limit load based strength estimator. Failure mode associated with the predicted failure strength can also be identified. It is shown that the cross tension strength of an SPR joint depends on the material and gage combinations, rivet design, die design and riveting direction. The analytical rivet strength estimator is then validated by experimental rivet strength measurements and failure mode observations from nine SPR joint populations with various material and gage combinations. Next, the estimator is used to optimize rivet strength. Two illustrative examples are presented in which rivet strength is improved by changing rivet length and riveting direction from the original manufacturing parameters.

  10. Load limit of a UASB fed septic tank-treated domestic wastewater.

    PubMed

    Lohani, Sunil Prasad; Bakke, Rune; Khanal, Sanjay N

    2015-01-01

    Performance of a 250 L pilot-scale up-flow anaerobic sludge blanket (UASB) reactor, operated at ambient temperatures, fed septic tank effluents intermittently, was monitored for hydraulic retention time (HRT) from 18 h to 4 h. The total suspended solids (TSS), total chemical oxygen demand (CODT), dissolved chemical oxygen demand (CODdis) and suspended chemical oxygen demand (CODss) removal efficiencies ranged from 20 to 63%, 15 to 56%, 8 to 35% and 22 to 72%, respectively, for the HRT range tested. Above 60% TSS and 47% CODT removal were obtained in the combined septic tank and UASB process. The process established stable UASB treatment at HRT≥6 h, indicating a hydraulic load design limit. The tested septic tank-UASB combined system can be a low-cost and effective on-site sanitation solution.

  11. 49 CFR 393.108 - How is the working load limit of a tiedown, or the load restraining value of a friction mat...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... for grade 30 proof coil chain. (e)(1) Wire rope which is not marked by the manufacturer with a working... listed in the Wire Rope Users Manual. (2) Wire which is not marked or labeled to enable identification of... core wire rope. (f) Manila rope which is not marked by the manufacturer with a working load limit...

  12. 49 CFR 393.108 - How is the working load limit of a tiedown, or the load restraining value of a friction mat...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... for grade 30 proof coil chain. (e)(1) Wire rope which is not marked by the manufacturer with a working... listed in the Wire Rope Users Manual. (2) Wire which is not marked or labeled to enable identification of... core wire rope. (f) Manila rope which is not marked by the manufacturer with a working load limit...

  13. 49 CFR 393.108 - How is the working load limit of a tiedown, or the load restraining value of a friction mat...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... for grade 30 proof coil chain. (e)(1) Wire rope which is not marked by the manufacturer with a working... listed in the Wire Rope Users Manual. (2) Wire which is not marked or labeled to enable identification of... core wire rope. (f) Manila rope which is not marked by the manufacturer with a working load limit...

  14. 49 CFR 393.108 - How is the working load limit of a tiedown, or the load restraining value of a friction mat...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... for grade 30 proof coil chain. (e)(1) Wire rope which is not marked by the manufacturer with a working... listed in the Wire Rope Users Manual. (2) Wire which is not marked or labeled to enable identification of... core wire rope. (f) Manila rope which is not marked by the manufacturer with a working load limit...

  15. 40 CFR 130.7 - Total maximum daily loads (TMDL) and individual water quality-based effluent limitations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... individual water quality-based effluent limitations. 130.7 Section 130.7 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS WATER QUALITY PLANNING AND MANAGEMENT § 130.7 Total maximum daily loads (TMDL) and individual water quality-based effluent limitations. (a) General. The...

  16. 40 CFR 130.7 - Total maximum daily loads (TMDL) and individual water quality-based effluent limitations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... individual water quality-based effluent limitations. 130.7 Section 130.7 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS WATER QUALITY PLANNING AND MANAGEMENT § 130.7 Total maximum daily loads (TMDL) and individual water quality-based effluent limitations. (a) General. The...

  17. The theoretical limits to the power output of a muscle-tendon complex with inertial and gravitational loads.

    PubMed Central

    Galantis, Apostolos; Woledge, Roger C

    2003-01-01

    When a muscle delivers power to an inertial load through a spring, the peak power can exceed the maximum that the muscle alone could produce. Using normalized differential equations relating dimensionless quantities we show, by solving the equations either analytically or numerically, that one dimensionless constant (Xi), representing the inertial load, is sufficient to specify the behaviour during shortening of a muscle-tendon complex with linear force-velocity and force-extension properties. In the presence of gravity, an additional constant (Gamma), representing the gravitational acceleration, is required. Nonlinear force-velocity and force-extension relationships each introduce an additional constant, representing their curvature. In the absence of gravity the power output delivered to an inertial load is limited to approximately 1.4 times the maximum power of the muscle alone, and when gravity is present the power delivered is limited to approximately twice the power of muscle alone. These limits are found for the purely inertial load at Xi ca. 1 and with gravity acting at XiGamma = 0.5 with Xi arbitrarily small. The effects of nonlinear muscle and tendon properties tend to cancel each other out and do not produce large deviations from these optima. A lever system of constant ratio between muscle and load does not alter these limits. Cams and catches are required to exceed these limits and attain the high power outputs sometimes observed during explosive animal movement. PMID:12965015

  18. The theoretical limits to the power output of a muscle-tendon complex with inertial and gravitational loads.

    PubMed

    Galantis, Apostolos; Woledge, Roger C

    2003-07-22

    When a muscle delivers power to an inertial load through a spring, the peak power can exceed the maximum that the muscle alone could produce. Using normalized differential equations relating dimensionless quantities we show, by solving the equations either analytically or numerically, that one dimensionless constant (Xi), representing the inertial load, is sufficient to specify the behaviour during shortening of a muscle-tendon complex with linear force-velocity and force-extension properties. In the presence of gravity, an additional constant (Gamma), representing the gravitational acceleration, is required. Nonlinear force-velocity and force-extension relationships each introduce an additional constant, representing their curvature. In the absence of gravity the power output delivered to an inertial load is limited to approximately 1.4 times the maximum power of the muscle alone, and when gravity is present the power delivered is limited to approximately twice the power of muscle alone. These limits are found for the purely inertial load at Xi ca. 1 and with gravity acting at XiGamma = 0.5 with Xi arbitrarily small. The effects of nonlinear muscle and tendon properties tend to cancel each other out and do not produce large deviations from these optima. A lever system of constant ratio between muscle and load does not alter these limits. Cams and catches are required to exceed these limits and attain the high power outputs sometimes observed during explosive animal movement.

  19. Improving the Chest Protection of Elderly Occupants in Frontal Crashes Using SMART Load Limiters.

    PubMed

    Ekambaram, Karthikeyan; Frampton, Richard; Bartlett, Lisa

    2015-01-01

    To determine whether varying the seat belt load limiter (SBL) according to crash and occupant characteristics could have real-world injury reduction benefits in frontal impacts and, if so, to quantify those benefits. Real-world UK accident data were used to identify the target population of vehicle occupants and frontal crash scenarios where improved chest protection could be most beneficial. Generic baseline driver and front passenger numerical models using a 50th percentile dummy were developed with MADYMO software. Simulations were performed where the load limiter threshold was varied in selected frontal impact scenarios. For each SBL setting, restraint performance, dummy kinematics, and injury outcome were studied in 5 different frontal impact types. Thoracic injury predictions were converted into injury probability values using Abbreviated Injury Scale (AIS) 2+ age-dependent thoracic risk curves developed and validated based on a methodology proposed by Laituri et al. (2005). Real-world benefit was quantified using the predicted AIS 2+ risk and assuming that an appropriate adaptive system was fitted to all the cars in a real-world sample of recent frontal crashes involving European passenger cars. From the accident data sample the chest was the most frequently injured body region at an AIS 2+ level in frontal impacts (7% of front seat occupants). The proportion of older vehicle front seat occupants (>64 years) with AIS 2+ injury was also greater than the proportion of younger occupants. Additionally, older occupants were more likely to sustain seat belt-induced serious chest injury in low- and moderate-speed frontal crashes. In both front seating positions, the low SBL provided the best chest injury protection, without increasing the risk to other body regions. In severe impacts, the low SBL allowed the driver to move dangerously close to the steering wheel. Compared to the driver side, greater ride-down space on the passenger side gave a higher potential for

  20. Wheel/rail contact geometry assessment to limit rolling contact fatigue initiation at high axle loads

    NASA Astrophysics Data System (ADS)

    Fröhling, Robert; Spangenberg, Ulrich; Hettasch, Georg

    2012-01-01

    Rolling contact fatigue on any railway system has a significant impact on the safety and efficiency of the operation. This is especially true for heavy haul railways where higher axle loads and demands for higher throughput have, over the years, challenged the limits within the wheel/rail interface. The objective of this paper is to present a methodology to manage this stress state using a detailed wheel/rail contact stress analysis. Based on the results of recent wheel profile and rail profile surveys, a kinematic wheel/rail contact analysis is performed to identify and eliminate profiles that cause high stresses. The results show that the current hollow wear criterion is effective, but that an alternative or additional criterion based on the gauge side false flange gradient or the calculated peak contact stress values can further reduce the stress state. Within the wheel and rail profile combinations investigated, the contact stresses were largely independent of the transverse profile of the high rail.

  1. Optimal Wastewater Loading under Conflicting Goals and Technology Limitations in a Riverine System.

    PubMed

    Rafiee, Mojtaba; Lyon, Steve W; Zahraie, Banafsheh; Destouni, Georgia; Jaafarzadeh, Nemat

    2017-03-01

      This paper investigates a novel simulation-optimization (S-O) framework for identifying optimal treatment levels and treatment processes for multiple wastewater dischargers to rivers. A commonly used water quality simulation model, Qual2K, was linked to a Genetic Algorithm optimization model for exploration of relevant fuzzy objective-function formulations for addressing imprecision and conflicting goals of pollution control agencies and various dischargers. Results showed a dynamic flow dependence of optimal wastewater loading with good convergence to near global optimum. Explicit considerations of real-world technological limitations, which were developed here in a new S-O framework, led to better compromise solutions between conflicting goals than those identified within traditional S-O frameworks. The newly developed framework, in addition to being more technologically realistic, is also less complicated and converges on solutions more rapidly than traditional frameworks. This technique marks a significant step forward for development of holistic, riverscape-based approaches that balance the conflicting needs of the stakeholders.

  2. Calculation of Centrally Loaded Thin-Walled Columns Above the Buckling Limit

    NASA Technical Reports Server (NTRS)

    Reinitzhuber, F.

    1945-01-01

    When thin-walled columns formed from flanged sheet, such as used in airplane construction, are subjected to axial load, their behavior at failure varies according to the slenderness ratio. On long columns the axis deflects laterally while the cross section form is maintained; buckling results. The respective breaking load in the elastic range is computed by Euler's formula and for the plastic range by the Engesser- Karman formula. Its magnitude is essentially dependent upon the length. On intermediate length columns, especially where open sections are concerned, the cross section is distorted while the cross section form is preserved; twisting failure results. The buckling load in twisting is calculated according to Wagner and Kappus. On short columns the straight walls of low-bending resistance that form the column are deflected at the same time that the cross section form changes - buckling occurs without immediate failure. Then the buckling load of the total section computable from the buckling loads of the section walls is not the ultimate load; quite often, especially on thin-walled sections, it lies considerably higher and is secured by tests. Both loads, the buckling and the ultimate load are only in a small measure dependent upon length. The present report is an attempt to theoretically investigate the behavior of such short, thin-walled columns above the buckling load with the conventional calculating methods.

  3. Comparison of Thoracic Injury Risk in Frontal Car Crashes for Occupant Restrained without Belt Load Limiters and Those Restrained with 6 kN and 4 kN Belt Load Limiters.

    PubMed

    Foret-Bruno, J Y; Trosseille, X; Page, Y; Huère, J F; Le Coz, J Y; Bendjellal, F; Diboine, A; Phalempin, T; Villeforceix, D; Baudrit, P; Guillemot, H; Coltat, J C

    2001-11-01

    In France, as in other countries, accident research studies show that a large proportion of restrained occupants who sustain severe or fatal injuries are involved in frontal impacts (65% and 50%, respectively). In severe frontal impacts with restrained occupants and where intrusion is not preponderant, the oldest occupants very often sustain severe thoracic injuries due to the conventional seat belt. As we have been observing over the last years, we will expect in the coming years developments which include more solidly-built cars, as offset crash test procedures are widely used to evaluate the passive safety of production vehicles. The reduction of intrusion for the most severe frontal impacts, through optimization of car deformation, usually translates into an increase in restraint forces and hence thoracic injury risk with a conventional retractor seat belt for a given impact severity. It is, therefore essential to limit the restraint forces exerted by the seat belt on the thorax in order to reduce the number of road casualties. In order to address thoracic injury risk in frontal impact, Renault cars have been equipped with the Programmed Restraint System (PRS) since 1995. The PRS is a restraint system that combines belt load limitation and pyrotechnic belt pretension. In an initial design of the Programmed Restraint System (PRS1), the belt load limiter was a steel component designed to shear at a given shoulder force, namely 6 kN. It was mounted between the retractor and the lower anchorage point of the belt. The design of the PRS was modified in 1998 (PRS2), but the principle of load limitation was maintained. The threshold was decreased to 4 kN and this lower belt belt-force limiter has been combined with a specially designed airbag. This paper reports on 347 real-world frontal accidents where the EES (Equivalent Energy Speed) ranged from 35 to 75 km/h. One hundred and ninety-eight (198) of these accidents involved cars equipped with the 6 kN load limiter

  4. 29 CFR 1919.75 - Determination of crane or derrick safe working loads and limitations in absence of manufacturer's...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 7 2013-07-01 2013-07-01 false Determination of crane or derrick safe working loads and limitations in absence of manufacturer's data. 1919.75 Section 1919.75 Labor Regulations Relating to Labor... Certification of Shore-Based Material Handling Devices § 1919.75 Determination of crane or derrick safe working...

  5. 29 CFR 1919.75 - Determination of crane or derrick safe working loads and limitations in absence of manufacturer's...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Determination of crane or derrick safe working loads and limitations in absence of manufacturer's data. 1919.75 Section 1919.75 Labor Regulations Relating to Labor... Certification of Shore-Based Material Handling Devices § 1919.75 Determination of crane or derrick safe working...

  6. 29 CFR 1919.75 - Determination of crane or derrick safe working loads and limitations in absence of manufacturer's...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 7 2012-07-01 2012-07-01 false Determination of crane or derrick safe working loads and limitations in absence of manufacturer's data. 1919.75 Section 1919.75 Labor Regulations Relating to Labor... Certification of Shore-Based Material Handling Devices § 1919.75 Determination of crane or derrick safe working...

  7. 29 CFR 1919.75 - Determination of crane or derrick safe working loads and limitations in absence of manufacturer's...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 7 2014-07-01 2014-07-01 false Determination of crane or derrick safe working loads and limitations in absence of manufacturer's data. 1919.75 Section 1919.75 Labor Regulations Relating to Labor... Certification of Shore-Based Material Handling Devices § 1919.75 Determination of crane or derrick safe working...

  8. 29 CFR 1919.75 - Determination of crane or derrick safe working loads and limitations in absence of manufacturer's...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Determination of crane or derrick safe working loads and limitations in absence of manufacturer's data. 1919.75 Section 1919.75 Labor Regulations Relating to Labor... Certification of Shore-Based Material Handling Devices § 1919.75 Determination of crane or derrick safe working...

  9. Estimation of fatigue and extreme load distributions from limited data with application to wind energy systems.

    SciTech Connect

    Fitzwater, LeRoy M.

    2004-01-01

    An estimate of the distribution of fatigue ranges or extreme loads for wind turbines may be obtained by separating the problem into two uncoupled parts, (1) a turbine specific portion, independent of the site and (2) a site-specific description of environmental variables. We consider contextually appropriate probability models to describe the turbine specific response for extreme loads or fatigue. The site-specific portion is described by a joint probability distribution of a vector of environmental variables, which characterize the wind process at the hub-height of the wind turbine. Several approaches are considered for combining the two portions to obtain an estimate of the extreme load, e.g., 50-year loads or fatigue damage. We assess the efficacy of these models to obtain accurate estimates, including various levels of epistemic uncertainty, of the turbine response.

  10. Egg load dynamics and the risk of egg and time limitation experienced by an aphid parasitoid in the field

    PubMed Central

    Dieckhoff, Christine; Theobald, Julian C; Wäckers, Felix L; Heimpel, George E

    2014-01-01

    Insect parasitoids and herbivores must balance the risk of egg limitation and time limitation in order to maximize reproductive success. Egg and time limitation are mediated by oviposition and egg maturation rates as well as by starvation risk and other determinants of adult lifespan. Here, we assessed egg load and nutritional state in the soybean aphid parasitoid Binodoxys communis under field conditions to estimate its risk of becoming either egg- or time-limited. The majority of female B. communis showed no signs of egg limitation. Experimental field manipulations of B. communis females suggested that an average of 4–8 eggs were matured per hour over the course of a day. Regardless, egg loads remained constant over the course of the day at approximately 80 eggs, suggesting that egg maturation compensates for oviposition. This is the first case of such “egg load buffering” documented for a parasitoid in the field. Despite this buffering, egg loads dropped slightly with increasing host (aphid) density. This suggests that egg limitation could occur at very high host densities as experienced in outbreak years in some locations in the Midwestern USA. Biochemical analyses of sugar profiles showed that parasitoids fed upon sugar in the field at a remarkably high rate. Time limitation through starvation thus seems to be very low and aphid honeydew is most likely a source of dietary sugar for these parasitoids. This latter supposition is supported by the fact that body sugar levels increase with host (aphid) density. Together, these results suggest that fecundity of B. communis benefits from both dynamic egg maturation strategies and sugar-feeding. PMID:24963373

  11. Cellulose accessibility limits the effectiveness of minimum cellulase loading on the efficient hydrolysis of pretreated lignocellulosic substrates

    PubMed Central

    2011-01-01

    A range of lignocellulosic feedstocks (including agricultural, softwood and hardwood substrates) were pretreated with either sulfur dioxide-catalyzed steam or an ethanol organosolv procedure to try to establish a reliable assessment of the factors governing the minimum protein loading that could be used to achieve efficient hydrolysis. A statistical design approach was first used to define what might constitute the minimum protein loading (cellulases and β-glucosidase) that could be used to achieve efficient saccharification (defined as at least 70% glucan conversion) of the pretreated substrates after 72 hours of hydrolysis. The likely substrate factors that limit cellulose availability/accessibility were assessed, and then compared with the optimized minimum amounts of protein used to obtain effective hydrolysis. The optimized minimum protein loadings to achieve efficient hydrolysis of seven pretreated substrates ranged between 18 and 63 mg protein per gram of glucan. Within the similarly pretreated group of lignocellulosic feedstocks, the agricultural residues (corn stover and corn fiber) required significantly lower protein loadings to achieve efficient hydrolysis than did the pretreated woody biomass (poplar, douglas fir and lodgepole pine). Regardless of the substantial differences in the source, structure and chemical composition of the feedstocks, and the difference in the pretreatment technology used, the protein loading required to achieve efficient hydrolysis of lignocellulosic substrates was strongly dependent on the accessibility of the cellulosic component of each of the substrates. We found that cellulose-rich substrates with highly accessible cellulose, as assessed by the Simons' stain method, required a lower protein loading per gram of glucan to obtain efficient hydrolysis compared with substrates containing less accessible cellulose. These results suggest that the rate-limiting step during hydrolysis is not the catalytic cleavage of the

  12. Effect of Large Scale Transmission Limitations on Renewable Energy Load Matching for Western U.S.: Preprint

    SciTech Connect

    Diakov, V.; Short, W.; Gilchrist, B.

    2012-06-01

    Based on the available geographically dispersed data for the Western U.S. (excluding Alaska), we analyze to what extent the geographic diversity of these resources can offset their variability. Without energy storage and assuming unlimited energy flows between regions, wind and PV can meet up to 80% of loads in Western U.S. while less than 10% of the generated power is curtailed. Limiting hourly energy flows by the aggregated transmission line carrying capacities decreases the fraction of the load that can be met with wind and PV generation to approximately 70%.

  13. PIC simulations of conical magnetically insulated transmission line with LTD generator: Transition from self-limited to load-limited flow

    NASA Astrophysics Data System (ADS)

    Liu, Laqun; Wang, Huihui; Guo, Fan; Zou, Wenkang; Liu, Dagang

    2017-04-01

    Based on the 3-dimensional Particle-In-Cell (PIC) code CHIPIC3D, with a new circuit boundary algorithm we developed, a conical magnetically insulated transmission line (MITL) with a 1.0-MV linear transformer driver (LTD) is explored numerically. The values of switch jitter time of LTD are critical parameters for the system, which are difficult to be measured experimentally. In this paper, these values are obtained by comparing the PIC results with experimental data of large diode-gap MITL. By decreasing the diode gap, we find that all PIC results agree well with experimental data only if MITL works on self-limited flow no matter how large the diode gap is. However, when the diode gap decreases to a threshold, the self-limited flow would transfer to a load-limited flow. In this situation, PIC results no longer agree with experimental data anymore due to the anode plasma expansion in the diode load. This disagreement is used to estimate the plasma expansion speed.

  14. Internal cycling, not external loading, decides the nutrient limitation in eutrophic lake: A dynamic model with temporal Bayesian hierarchical inference.

    PubMed

    Wu, Zhen; Liu, Yong; Liang, Zhongyao; Wu, Sifeng; Guo, Huaicheng

    2017-06-01

    Lake eutrophication is associated with excessive anthropogenic nutrients (mainly nitrogen (N) and phosphorus (P)) and unobserved internal nutrient cycling. Despite the advances in understanding the role of external loadings, the contribution of internal nutrient cycling is still an open question. A dynamic mass-balance model was developed to simulate and measure the contributions of internal cycling and external loading. It was based on the temporal Bayesian Hierarchical Framework (BHM), where we explored the seasonal patterns in the dynamics of nutrient cycling processes and the limitation of N and P on phytoplankton growth in hyper-eutrophic Lake Dianchi, China. The dynamic patterns of the five state variables (Chla, TP, ammonia, nitrate and organic N) were simulated based on the model. Five parameters (algae growth rate, sediment exchange rate of N and P, nitrification rate and denitrification rate) were estimated based on BHM. The model provided a good fit to observations. Our model results highlighted the role of internal cycling of N and P in Lake Dianchi. The internal cycling processes contributed more than external loading to the N and P changes in the water column. Further insights into the nutrient limitation analysis indicated that the sediment exchange of P determined the P limitation. Allowing for the contribution of denitrification to N removal, N was the more limiting nutrient in most of the time, however, P was the more important nutrient for eutrophication management. For Lake Dianchi, it would not be possible to recover solely by reducing the external watershed nutrient load; the mechanisms of internal cycling should also be considered as an approach to inhibit the release of sediments and to enhance denitrification. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Low Substrate Loading Limits Methanogenesis and Leads to High Coulombic Efficiency in Bioelectrochemical Systems.

    PubMed

    Sleutels, Tom H J A; Molenaar, Sam D; Heijne, Annemiek Ter; Buisman, Cees J N

    2016-01-05

    A crucial aspect for the application of bioelectrochemical systems (BESs) as a wastewater treatment technology is the efficient oxidation of complex substrates by the bioanode, which is reflected in high Coulombic efficiency (CE). To achieve high CE, it is essential to give a competitive advantage to electrogens over methanogens. Factors that affect CE in bioanodes are, amongst others, the type of wastewater, anode potential, substrate concentration and pH. In this paper, we focus on acetate as a substrate and analyze the competition between methanogens and electrogens from a thermodynamic and kinetic point of view. We reviewed experimental data from earlier studies and propose that low substrate loading in combination with a sufficiently high anode overpotential plays a key-role in achieving high CE. Low substrate loading is a proven strategy against methanogenic activity in large-scale reactors for sulfate reduction. The combination of low substrate loading with sufficiently high overpotential is essential because it results in favorable growth kinetics of electrogens compared to methanogens. To achieve high current density in combination with low substrate concentrations, it is essential to have a high specific anode surface area. New reactor designs with these features are essential for BESs to be successful in wastewater treatment in the future.

  16. Low Substrate Loading Limits Methanogenesis and Leads to High Coulombic Efficiency in Bioelectrochemical Systems

    PubMed Central

    Sleutels, Tom H. J. A.; Molenaar, Sam D.; Heijne, Annemiek Ter; Buisman, Cees J. N.

    2016-01-01

    A crucial aspect for the application of bioelectrochemical systems (BESs) as a wastewater treatment technology is the efficient oxidation of complex substrates by the bioanode, which is reflected in high Coulombic efficiency (CE). To achieve high CE, it is essential to give a competitive advantage to electrogens over methanogens. Factors that affect CE in bioanodes are, amongst others, the type of wastewater, anode potential, substrate concentration and pH. In this paper, we focus on acetate as a substrate and analyze the competition between methanogens and electrogens from a thermodynamic and kinetic point of view. We reviewed experimental data from earlier studies and propose that low substrate loading in combination with a sufficiently high anode overpotential plays a key-role in achieving high CE. Low substrate loading is a proven strategy against methanogenic activity in large-scale reactors for sulfate reduction. The combination of low substrate loading with sufficiently high overpotential is essential because it results in favorable growth kinetics of electrogens compared to methanogens. To achieve high current density in combination with low substrate concentrations, it is essential to have a high specific anode surface area. New reactor designs with these features are essential for BESs to be successful in wastewater treatment in the future. PMID:27681899

  17. Numerical simulation of load-induced bone structural remodelling using stress-limit criterion.

    PubMed

    Marzban, Ali; Nayeb-Hashemi, Hamid; Vaziri, Ashkan

    2015-01-01

    A simple and efficient numerical method for predicting the remodelling of adaptive materials and structures under applied loading was presented and implemented within a finite element framework. The model uses the trajectorial architecture theory of optimisation to predict the remodelling of material microstructure and structural organisation under mechanical loading. We used the proposed model to calculate the density distribution of proximal femur in the frontal plane. The loading considered was the hip joint contact forces and muscular forces at the attachment sites of the muscles to the bone. These forces were estimated from a separate finite element calculation using a heterogeneous three-dimensional model of the proximal femur. The density distributions obtained by this procedure has a qualitative similarity with in vivo observations. Solutions displayed the characteristic high-density channels that are evident in the Dual X-ray Absorptiometry scan. There is also evidence of the intramedullary canal, as well as low-density regions in the femoral neck. Several parametric studies were carried out to highlight the advantages of the proposed method, which includes fast convergence and low-computational cost. The potential applications of the proposed method in predicting bone structural remodelling in cancer are also briefly discussed.

  18. Aggravated phosphorus limitation on biomass production under increasing nitrogen loading: a meta-analysis.

    PubMed

    Li, Yong; Niu, Shuli; Yu, Guirui

    2016-02-01

    Nitrogen (N) and phosphorus (P), either individually or in combination, have been demonstrated to limit biomass production in terrestrial ecosystems. Field studies have been extensively synthesized to assess global patterns of N impacts on terrestrial ecosystem processes. However, to our knowledge, no synthesis has been done so far to reveal global patterns of P impacts on terrestrial ecosystems, especially under different nitrogen (N) levels. Here, we conducted a meta-analysis of impacts of P addition, either alone or with N addition, on aboveground (AGB) and belowground biomass production (BGB), plant and soil P concentrations, and N : P ratio in terrestrial ecosystems. Overall, our meta-analysis quantitatively confirmed existing notions: (i) colimitation of N and P on biomass production and (ii) more P limitation in tropical forest than other ecosystems. More importantly, our analysis revealed new findings: (i) P limitation on biomass production was aggravated by N enrichment and (ii) plant P concentration was a better indicator of P limitation than soil P availability. Specifically, P addition increased AGB and BGB by 34% and 13%, respectively. The effect size of P addition on biomass production was larger in tropical forest than grassland, wetland, and tundra and varied with P fertilizer forms, P addition rates, or experimental durations. The P-induced increase in biomass production and plant P concentration was larger under elevated than ambient N. Our findings suggest that the global limitation of P on biomass production will become severer under increasing N fertilizer and deposition in the future.

  19. Limit analysis for combined edge and pressure loading on a cylindrical shell.

    NASA Technical Reports Server (NTRS)

    Ho, H. S.; Updike, D. P.

    1971-01-01

    Equations describing the stress field and velocity field occurring in a circular cylindrical shell at plastic collapse are derived corresponding to stress states lying on each face of a yield surface for a uniform shell of material obeying the Tresca yield condition. They are then applied to the case of a shell under combined axisymmetric loadings (moment, shear force, and axial force) at one end and uniform internal or external pressure on the lateral surface. For a sufficiently long shell, complete solutions are obtained for a fixed far end, and for a certain range of values of axial force and pressure, they are obtained for a free far end. All the solutions are represented by either closed form or by quadratures. It is shown that in many cases the radial velocity field is proportional to the shear force.

  20. The Integration of a Load Limiter to an Orbiter Over-Center Mechanism

    NASA Technical Reports Server (NTRS)

    Gilmore, Adam; Rupp, Tim

    2004-01-01

    This paper summarizes the design process used to relieve the predicted high loads on a Space Shuttle Orbiter mechanism prior to the STS-112 flight. The overloading of the mechanism was due to a dynamic response between the orbiter and payload that was specific to this payload s mass and attachment scheme. A solution was devised by adding a component that prevented overload of the mechanism. In addition, the introduction of the new component neither interfered with the normal operation nor required extra-vehicular activity from a crewmember. By utilizing rapid prototyping technology, engineers were able to verify clearances and feasibility while preparing to build the flight hardware. This design solution was successfully flown on STS-112 and STS-113.

  1. Hydraulic mechanism to limit torsional loads between the IUS and space transportation system orbiter

    NASA Technical Reports Server (NTRS)

    Farmer, James R.

    1986-01-01

    The Inertial Upper Stage (IUS) is a two-stage booster used by NASA and the Defense Department to insert payloads into geosynchronous orbit from low-Earth orbit. The hydraulic mechanism discussed here was designed to perform a specific dynamic and static interface function within the Space Transportation System's Orbiter. Requirements, configuration, and application of the hydraulic mechanism with emphasis on performance and methods of achieving zero external hydraulic leakage are discussed. The hydraulic load-leveler mechanism meets the established design requirements for operation in a low-Earth orbit. Considerable testing was conducted to demonstrate system performance and verification that external leakage had been reduced to zero. Following each flight use of an ASE, all hydraulic mechanism components are carefully inspected for leakage. The ASE, including the hydraulic mechanism, has performed without any anomalies during all IUS flights.

  2. 76 FR 32323 - Limited Service Domestic Voyage Load Lines for River Barges on Lake Michigan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-06

    ... established in the final rule published on November 18, 2010. Specifically, the weather restrictions based on Small Craft Advisory conditions are being replaced with the original weather restrictions implemented in...) conditions as the limiting weather restrictions in place of a variety of weather conditions used under the...

  3. Shoulder muscle forces during driving: Sudden steering can load the rotator cuff beyond its repair limit.

    PubMed

    Pandis, Petros; Prinold, Joe A I; Bull, Anthony M J

    2015-10-01

    Driving is one of the most common everyday tasks and the rotator cuff muscles are the primary shoulder stabilisers. Muscle forces during driving are not currently known, yet knowledge of these would influence important clinical advice such as return to activities after surgery. The aim of this study is to quantify shoulder and rotator cuff muscle forces during driving in different postures. A musculoskeletal modelling approach is taken, using a modified driving simulator in combination with an upper limb musculoskeletal model (UK National Shoulder Model). Motion data and external force vectors were model inputs and upper limb muscle and joint forces were the outputs. Comparisons of the predicted glenohumeral joint forces were compared to in vivo literature values, with good agreement demonstrated (61 SD 8% body weight mean peak compared to 60 SD 1% body weight mean peak). High muscle activation was predicted in the rotator cuff muscles; particularly supraspinatus (mean 55% of the maximum and up to 164 SD 27 N). This level of loading is up to 72% of mean failure strength for supraspinatus repairs, and could therefore be dangerous for some cases. Statistically significant and large differences are shown to exist in the joint and muscle forces for different driving positions as well as steering with one or both hands (up to 46% body weight glenohumeral joint force). These conclusions should be a key consideration in rehabilitating the shoulder after surgery, preventing specific upper limb injuries and predicting return to driving recommendations. Copyright © 2015. Published by Elsevier Ltd.

  4. Limiter

    DOEpatents

    Cohen, S.A.; Hosea, J.C.; Timberlake, J.R.

    1984-10-19

    A limiter with a specially contoured front face is provided. The front face of the limiter (the plasma-side face) is flat with a central indentation. In addition, the limiter shape is cylindrically symmetric so that the limiter can be rotated for greater heat distribution. This limiter shape accommodates the various power scrape-off distances lambda p, which depend on the parallel velocity, V/sub parallel/, of the impacting particles.

  5. Small amplitude, free longitudinal vibrations of a load on a finitely deformed stress-softening spring with limiting extensibility

    NASA Astrophysics Data System (ADS)

    Beatty, M. F.; Bhattacharyya, R.; Sarangi, S.

    2009-09-01

    A constitutive theory for a general class of incompressible, isotropic stress-softening, limited elastic rubberlike materials is introduced. The model is applied to study the small amplitude, free longitudinal vibrational frequency of a load about a suspended static equilibrium stretch of a finitely deformed, stress-softening spring with limiting extensibility. A number of physical results, including bounds on the frequency, are reported. It is proved, for example, that the normalized vibrational frequency for the ideally elastic neo-Hookean oscillator is a lower bound for the normalized frequency of every incompressible, isotropic stress-softening, limited elastic oscillator within the general class. All results are illustrated for the special limited elastic Gent and the purely elastic Demiray biomaterial models, both with stress-softening characterized by a Zúñiga-Beatty front factor damage function. The results for both stress-softening models are compared with experimental data for several gum rubbers and thoracic aortic tissue provided by others; and, overall, it is found that the stress-softening, limited elastic Gent model best characterizes the data.

  6. Limiter

    DOEpatents

    Cohen, Samuel A.; Hosea, Joel C.; Timberlake, John R.

    1986-01-01

    A limiter with a specially contoured front face accommodates the various power scrape-off distances .lambda..sub.p, which depend on the parallel velocity, V.sub..parallel., of the impacting particles. The front face of the limiter (the plasma-side face) is flat with a central indentation. In addition, the limiter shape is cylindrically symmetric so that the limiter can be rotated for greater heat distribution.

  7. The dependence of viral parameter estimates on the assumed viral life cycle: limitations of studies of viral load data.

    PubMed Central

    Lloyd, A. L.

    2001-01-01

    Estimation of viral parameters, such as the basic reproductive number (R0) and infected cell life span, is central to the quantitative study of the within-host dynamics of viral diseases such as human immunodeficiency virus, hepatitis B or hepatitis C. As these parameters can rarely be determined directly, they are usually estimated indirectly by fitting mathematical models to viral load data. This paper investigates how parameter estimates obtained by such procedures depend on the assumptions made concerning the viral life cycle. It finds that estimates of the basic reproductive number obtained using viral load data collected during the initial stages of infection can depend quite sensitively on these assumptions. The use of models which neglect the intracellular delay before virion production can lead to severe underestimates of R0 and, hence, to overly optimistic predictions of how efficacious treatment must be in order to prevent or eradicate the disease. These results are also of importance for attempts at estimating R0 from similar epidemiological data as there is a correspondence between within-host and between-host models. Estimates of the life span of infected cells obtained from viral load data collected during drug treatment studies also depend on the assumptions made in modelling the virus life cycle. The use of more realistic descriptions of the life cycle is seen to increase estimates of infected cell life span, in addition to providing a new explanation for the shoulder phase seen during drug treatment. This study highlights the limitations of what can be learnt by fitting mathematical models to infectious disease data without detailed independent knowledge of the life cycle of the infectious agent. PMID:11345331

  8. Dry Blood Spots a Reliable Method for Measurement of Hepatitis B Viral Load in Resource-Limited Settings

    PubMed Central

    Stene-Johansen, Kathrine; Yaqoob, Nadeem; Overbo, Joakim; Aberra, Hanna; Desalegn, Hailemichael; Berhe, Nega; Johannessen, Asgeir

    2016-01-01

    Background & Aims Hepatitis B virus (HBV) quantification is essential in the management of chronic hepatitis B, both to determine treatment eligibility and in the monitoring of treatment effect. This test, however, is rarely available in resource-limited settings due to high costs and stringent requirements for shipment and storage of plasma. Dried Blood Spots (DBS) can be a convenient alternative to plasma, but its use for HBV monitoring has not been investigated under real-life conditions in Africa. Methods The performance of DBS in HBV quantification was investigated using a modified commercial test (Abbott RealTime HBV assay). Paired DBS and plasma samples were collected from an HBV positive cohort in Addis Ababa, Ethiopia. DBS were stored at ambient temperature for 4–39 days before shipment to the laboratory. Results Twenty-six paired samples were selected covering the total range of quantification, from 2.14 log IU/ml to >7 log IU/ml. HBV was detected in 21 of 21 (100%) DBS from patients with a corresponding plasma viral load above 2.70 log IU/ml. The mean difference between plasma and DBS was 0.59 log IU/ml, and the correlation was strong (R2 = 0.92). In stability studies there was no significant change in DBS viral load after storage at room temperature for up to 12 weeks. Conclusions This study suggests that DBS can be a feasible and reliable alternative to plasma for quantification of HBV in resource-limited settings. DBS can expand access to antiviral treatment for patients in low- and middle-income countries. PMID:27820845

  9. SAMBA HIV semiquantitative test, a new point-of-care viral-load-monitoring assay for resource-limited settings.

    PubMed

    Ritchie, Allyson V; Ushiro-Lumb, Ines; Edemaga, Daniel; Joshi, Hrishikesh A; De Ruiter, Annemiek; Szumilin, Elisabeth; Jendrulek, Isabelle; McGuire, Megan; Goel, Neha; Sharma, Pia I; Allain, Jean-Pierre; Lee, Helen H

    2014-09-01

    Routine viral-load (VL) testing of HIV-infected individuals on antiretroviral therapy (ART) is used to monitor treatment efficacy. However, due to logistical challenges, implementation of VL has been difficult in resource-limited settings. The aim of this study was to evaluate the performance of the SAMBA semi-Q (simple amplification-based assay semiquantitative test for HIV-1) in London, Malawi, and Uganda. The SAMBA semi-Q can distinguish between patients with VLs above and below 1,000 copies/ml. The SAMBA semi-Q was validated with diluted clinical samples and blinded plasma samples collected from HIV-1-positive individuals. SAMBA semi-Q results were compared with results from the Roche COBAS AmpliPrep/COBAS TaqMan HIV-1 test, v2.0. Testing of 96 2- to 10-fold dilutions of four samples containing HIV-1 subtype C as well as 488 samples from patients in the United Kingdom, Malawi, and Uganda yielded an overall accuracy for the SAMBA semi-Q of 99% (95% confidence interval [CI], 93.8 to 99.9%) and 96.9% (95% CI 94.9 to 98.3%), respectively, compared to to the Roche test. Analysis of VL data from patients in Malawi and Uganda showed that the SAMBA cutoff of 1,000 copies/ml appropriately distinguished treated from untreated individuals. Furthermore, analysis of the viral loads of 232 patients on ART in Malawi and Uganda revealed similar patterns for virological control, defined as either <1,000 copies/ml (SAMBA cutoff) or <5,000 copies/ml (WHO 2010 criterion; WHO, Antiretroviral Therapy for HIV Infection in Adults and Adolescents: Recommendations for a Public Health Approach, 2010). This study suggests that the SAMBA semi-Q has adequate concurrency with the gold standard measurements for viral load. This test can allow VL monitoring of patients on ART at the point of care in resource-limited settings.

  10. Patient needs and point-of-care requirements for HIV load testing in resource-limited settings.

    PubMed

    Usdin, Martine; Guillerm, Martine; Calmy, Alexandra

    2010-04-15

    Medecins Sans Frontieres (MSF) is an international, independent medical nongovernmental organization. One way in which MSF acts to improve patient care is to assist in the identification and development of adapted and appropriate tools for use in resource-limited settings. One strategy to achieve this goal is through active collaborations with scientists and developers, to make some of the field needs known and to help define the medical strategy behind the implementation of new diagnostic tests. Tests used in the field need to be effective in often extreme conditions and must also deliver high-quality, reliable results that can be used in the local context. In this article, we discuss some patient and health care provider needs for human immunodeficiency virus (HIV) load measurement in resource-limited settings. This is just one of the areas in which effective, quality tools are desperately needed, not only by MSF and other international nongovernmental organizations, but also by many other health service providers. We hope that, by clearly defining the needs of patients in MSF clinics-as well as we can assess this-and by explaining why these tools are needed, how they should perform, and how their results can be integrated into a program, we will encourage the development of such tools and hasten their implementation in areas where they are so urgently needed.

  11. 40 CFR Table 2 to Subpart Bbbbbb... - Applicability Criteria, Emission Limits, and Management Practices for Loading Racks

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the TOC vapors displaced from cargo tanks during product loading; and(b) Reduce emissions of TOC to...) Design and operate the vapor collection system to prevent any TOC vapors collected at one loading rack...

  12. Current Limiting and Recovery Characteristics Under Load of Transformer Type SFCL with Rewound Structure Using BSCCO Wire in Model Power System

    NASA Astrophysics Data System (ADS)

    Noda, Sho; Oda, Sayaka; Mori, Masato; Hattori, Keisuke; Baba, Jumpei; Shirai, Yasuyuki

    We have proposed new design of a transformer type SFCL with primary and secondary superconducting coils which has rewound structure. For not so large fault current, the proposed SFCL limits the current by the inductive component by the normal transition of the flux shielding coil (secondary), and for larger fault current, it can give the resistive component additively by the normal transition of the primary coil. The recovery characteristics under load condition and repetitive limiting operation were experimentally investigated in a laboratory scale power system. The SFCL limited twice repetitive faults current and recovered quickly under load condition.

  13. 40 CFR Table 2 to Subpart Bbbbbb... - Applicability Criteria, Emission Limits, and Management Practices for Loading Racks

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... loading rack(s) with a vapor collection system designed to collect the TOC vapors displaced from cargo tanks during product loading; and(b) Reduce emissions of TOC to less than or equal to 80 mg/l of... collection system to prevent any TOC vapors collected at one loading rack or lane from passing through...

  14. Limitation of sludge biotic index application for control of a wastewater treatment plant working with shock organic and ammonium loadings.

    PubMed

    Drzewicki, Adam; Kulikowska, Dorota

    2011-11-01

    This study aimed to determine the relationship between activated sludge microfauna, the sludge biotic index (SBI) and the effluent quality of a full-scale municipal wastewater treatment plant (WWTP) working with shock organic and ammonium loadings caused by periodic wastewater delivery from septic tanks. Irrespective of high/low effluent quality in terms of COD, BOD5, ammonium and suspended solids, high SBI values (8-10), which correspond to the first quality class of sludge, were observed. High SBI values were connected with abundant taxonomic composition and the domination of crawling ciliates with shelled amoebae and attached ciliates. High SBI values, even at a low effluent quality, limit the usefulness of the index for monitoring the status of an activated sludge system and the effluent quality in municipal WWTP-treated wastewater from septic tanks. It was shown that a more sensitive indicator of effluent quality was a change in the abundance of attached ciliates with a narrow peristome (Vorticella infusionum and Opercularia coarctata), small flagellates and crawling ciliates (Acineria uncinata) feeding on flagellates.

  15. How the Impacts of N Loading on Resource Limitation, Functional Composition of Plankton, and Net Primary Production Influence Nitrate Uptake and Trophic Transfer in Lake Ecosystems

    NASA Astrophysics Data System (ADS)

    Ballantyne, F.; Mellard, J.

    2015-12-01

    Nitrogen (N) loading in aquatic ecosystems can have a multitude of effects. Increased N availability often elevates primary production, but typically also alters community composition and trophic structure. How all the myriad impacts of N loading conspire to produce whole ecosystem responses to perturbation is not well understood. To characterize how whole ecosystems response to perturbation along a gradient of N loading, we added nitrate (and phosphate) to large in situ aquatic mesocosms at different rates over the course of three months and quantified biomass distributions across multiple size classes, plankton community composition (including functional traits), and N flow among size classes in both the epilimnion and the hypolimnion prior and subsequent to a one week shading perturbation. Increased N loading resulted in greater rates of light attenuation with depth, which in turn selected for species with higher tolerance to light limitation and low inorganic C availability, but also resulted in increased rates of primary production and top-down grazing pressure. Different degrees of N loading resulted in different rates of nitrate uptake and trophic transfer, as calculated from 15N pulse-chase additions, both prior and subsequent to the shading pertubation, with the loading effect diminished after the perturbation. N loading was positively associated with the rate of N transfer between the epilimnion, where the N was added, and the hypolimnion. A complex picture of whole ecosystem response to perturbation along a gradient of N loading emerges. N loading appears to simplify resource competition among phytoplankton by alleviating N limitation to an extent, and at the same time supports elevated production across trophic levels. Nitrate uptake rate is contingent on standing stock phytoplankton biomass and resource limitation status. Rates of nitrate removal from the water column depend on how N loading alters the abiotic environment (primarily light availability

  16. Increased levels of HIV RNA detected in samples with viral loads close to the detection limit collected in Plasma Preparation Tubes (PPT).

    PubMed

    Griffith, Brigitte P; Mayo, Donald R

    2006-02-01

    The accurate and reliable quantification of HIV RNA is an essential part of the management of HIV infected individuals, and elucidation of factors that may affect HIV RNA measurements, such as the use of Vacutainer Plasma Preparation Tubes (PPT), is crucial. The objective of this study was to determine if plasma samples with viral loads close to the lower limit of the dynamic range of the assay collected in PPT tubes had increased levels of HIV RNA as compared to samples collected in standard EDTA tubes. HIV RNA levels were compared in 112 paired plasma samples collected in PPT and standard EDTA tubes. All samples had been frozen prior to testing. Discrepancies between PPT and EDTA tubes did not occur for samples with high viral loads. However, in samples with viral loads close to the lower limit of the dynamic range, levels of HIV RNA detected were higher in a large proportion of PPT as compared to the corresponding EDTA plasma samples. Forty percent of plasma pairs had no detectable HIV RNA in the EDTA aliquot, but had low levels of HIV RNA in the corresponding PPT aliquot. This prospective study underlines the need for cautious interpretation of small transient viral load changes in samples with values close to the detection limit.

  17. Load limiting behavior in CRS tether anchors as a method to mitigate head and neck injuries sustained by children in frontal crash.

    PubMed

    Kapoor, Tanya; Altenhof, William; Tot, Miroslav; Zhang, Wencheng; Howard, Andrew; Rasico, Jim; Zhu, Fuchun; Mizuno, Koji

    2008-01-01

    This study focuses on methods to reduce injuries, specifically in the head and neck region, sustained by children seated in forward-facing child restraint system during a frontal vehicle crash. The main objective of this research was to implement load-limiting behavior into the upper tether and lower LATCH anchors of the CRS in order to reduce the neck injury criteria by increasing forward head excursion. Federal Motor Vehicle Safety Standard 213 outlines that the maximum limit for head excursion of the child dummy should be 720 mm, and the neck injury criteria should be less than 0.33 beyond the first 30 ms of the impact. Working within these limits, a fully deformable finite element model of a child restraint seat incorporating a Hybrid III 3-year-old dummy has been previously developed that has been validated for frontal impacts under CMVSS 208 and FMVSS 213 testing conditions. Observations from this previous work have illustrated that despite the head excursion being significantly less than the proposed limit of 720 mm, values of the neck injury criteria exceeded the protection reference values. Values of the load limits for both upper tether and lower LATCH anchors were calculated based on two approaches, initially based upon neck injury criteria and then an energy-based approach. Three numerical models were developed incorporating a Hybrid III 3-year-old dummy, Q3 child dummy, and a child finite element model. Numerical simulations, utilizing the identical 213 testing conditions, were completed incorporating load-limiting capabilities of the upper tether and lower LATCH anchors. Evaluation of injury criteria based on the quantitative analysis of the simulations yielded that the implementation of load-limiting behavior in the upper tether and lower LATCH anchors was effective in reducing the head injury criteria by approximately 60 to 70%. Implementation of load-limiting behavior in the upper tether and lower LATCH anchors of the child restraint system

  18. 75 FR 78928 - Limited Service Domestic Voyage Load Lines for River Barges on Lake Michigan, Delay of Effective...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-17

    ... than 4 feet. Small Craft Advisories may also be issued when lake ice exists that could be hazardous to... Barges on Lake Michigan, Delay of Effective Date AGENCY: Coast Guard, DHS. ACTION: Notice of delay of... special load line regimes for certain river barges operating on Lake Michigan. This rule finalized interim...

  19. THE DEVELOPMENT OF EMPIRICAL LOAD-ECOLOGICAL RESPONSE MODELS TO DETERMINE NITROGEN LIMITS IN THE COASTAL ENVIRONMENT

    EPA Science Inventory

    The U.S. EPA Atlantic Ecology Division (AED) has initiated a multi-year research program to develop empirical nitrogen load-response models. Our research on embayments in southern New England is part of a multi-regional effort to develop cause-effect models for the Gulf of Mexic...

  20. Limits on the prediction of helicopter rotor noise using thickness and loading sources: Validation of helicopter noise prediction techniques

    NASA Technical Reports Server (NTRS)

    Succi, G. P.

    1983-01-01

    The techniques of helicopter rotor noise prediction attempt to describe precisely the details of the noise field and remove the empiricisms and restrictions inherent in previous methods. These techniques require detailed inputs of the rotor geometry, operating conditions, and blade surface pressure distribution. The Farassat noise prediction techniques was studied, and high speed helicopter noise prediction using more detailed representations of the thickness and loading noise sources was investigated. These predictions were based on the measured blade surface pressures on an AH-1G rotor and compared to the measured sound field. Although refinements in the representation of the thickness and loading noise sources improve the calculation, there are still discrepancies between the measured and predicted sound field. Analysis of the blade surface pressure data indicates shocks on the blades, which are probably responsible for these discrepancies.

  1. 76 FR 63822 - Special Conditions: Gulfstream Aerospace LP (GALP) Model G280 Airplane, Limit Engine Torque Loads...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-14

    ...These special conditions are issued for the Gulfstream Aerospace LP (GALP) model G280 airplane. This airplane will have a novel or unusual design feature associated with engine torque loads imposed by sudden engine stoppage. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for this design feature. These special conditions contain the additional safety standards that the Administrator considers necessary to establish a level of safety equivalent to that established by the existing airworthiness standards.

  2. Interpretation of real-time PCR results for hepatitis C virus RNA when viral load is below quantification limits.

    PubMed

    Laperche, Syria; Bouchardeau, Françoise; André-Garnier, Elisabeth; Thibault, Vincent; Roque-Afonso, Anne-Marie; Trimoulet, Pascale; Colimon, Ronald; Duverlie, Gilles; Leguillou-Guillemette, Hélène; Lunel, Françoise; Bouvier-Alias, Magali; Pawlotsky, Jean-Michel; Henquell, Cécile; Schvoerer, Evelyne; Stoll-Keller, Françoise; Chaix, Marie-Laure; Branger, Michel; Gaudy-Graffin, Catherine; Rosenberg, Arielle R; Pozzetto, Bruno; Vallet, Sophie; Baazia, Yazid; Izopet, Jacques; Lefrère, Jean-Jacques

    2011-03-01

    Hepatitis C virus RNA quantification results obtained in 18 laboratories using real-time PCR methods with 10 negative samples and 22 sample dilutions (viral loads of 0.5 to 500 IU/ml) showed a score of correct results of up to 93.5%. However, 55.6% of the laboratories did not follow the recommendations for the interpretation of their results, leading to ambiguous conclusions.

  3. Application Of A New Semi-Empirical Model For Forming Limit Prediction Of Sheet Material Including Superposed Loads Of Bending And Shearing

    SciTech Connect

    Held, Christian; Liewald, Mathias; Schleich, Ralf; Sindel, Manfred

    2010-06-15

    The use of lightweight materials offers substantial strength and weight advantages in car body design. Unfortunately such kinds of sheet material are more susceptible to wrinkling, spring back and fracture during press shop operations. For characterization of capability of sheet material dedicated to deep drawing processes in the automotive industry, mainly Forming Limit Diagrams (FLD) are used. However, new investigations at the Institute for Metal Forming Technology have shown that High Strength Steel Sheet Material and Aluminum Alloys show increased formability in case of bending loads are superposed to stretching loads. Likewise, by superposing shearing on in plane uniaxial or biaxial tension formability changes because of materials crystallographic texture. Such mixed stress and strain conditions including bending and shearing effects can occur in deep-drawing processes of complex car body parts as well as subsequent forming operations like flanging. But changes in formability cannot be described by using the conventional FLC. Hence, for purpose of improvement of failure prediction in numerical simulation codes significant failure criteria for these strain conditions are missing. Considering such aspects in defining suitable failure criteria which is easy to implement into FEA a new semi-empirical model has been developed considering the effect of bending and shearing in sheet metals formability. This failure criterion consists of the combination of the so called cFLC (combined Forming Limit Curve), which considers superposed bending load conditions and the SFLC (Shear Forming Limit Curve), which again includes the effect of shearing on sheet metal's formability.

  4. Development of lithium and tungsten limiters for test on T-10 tokamak at high heat load condition

    NASA Astrophysics Data System (ADS)

    Lyublinski, I. E.; Vertkov, A. V.; Zharkov, M. Yu; Vershkov, V. A.; Mirnov, S. V.

    2016-04-01

    Application of a complex of powerful (up to 3 MW) ECR plasma heating in T-10 tokamak is pulled down with a problem of the strong plasma pollution at power input more than 2 MW. For the solution of these problems the new W and Li limiters is developed and prepared to implementation. As it is supposed, application of W as a plasma facing material will allow excluding carbon influx into vacuum chamber. An additional Li limiter arranged in a shadow of W one will be used as a Li source for plasma periphery cooling due to a reradiation on Li that will lead to decrease in power deposition on W limiters. Parameters and design of limiters are presented. Plasma facing surface of a limiter is made of capillary-porous system (CPS) with Li. Porous matrix of CPS (W felt) provides stability of liquid Li surface under MHD force effect and an opportunity of its constant renewal due to capillary forces. The necessary Li flux from a Li limiter surface is estimated for maintenance of normal operation mode of W limiters at ECRH power of 3 MW during 400 ms. It is shown, that upgrade of limiters in tokamak T-10 will allow providing of ECR plasma heating with power up to 3 MW at reasonable Li flux.

  5. The value of point-of-care CD4+ and laboratory viral load in tailoring antiretroviral therapy monitoring strategies to resource limitations.

    PubMed

    Hyle, Emily P; Jani, Ilesh V; Rosettie, Katherine L; Wood, Robin; Osher, Benjamin; Resch, Stephen; Pei, Pamela P; Maggiore, Paolo; Freedberg, Kenneth A; Peter, Trevor; Parker, Robert A; Walensky, Rochelle P

    2017-09-24

    To examine the clinical and economic value of point-of-care CD4 (POC-CD4) or viral load monitoring compared with current practices in Mozambique, a country representative of the diverse resource limitations encountered by HIV treatment programs in sub-Saharan Africa. We use the Cost-Effectiveness of Preventing AIDS Complications-International model to examine the clinical impact, cost (2014 US$), and incremental cost-effectiveness ratio [$/year of life saved (YLS)] of ART monitoring strategies in Mozambique. We compare: monitoring for clinical disease progression [clinical ART monitoring strategy (CLIN)] vs. annual POC-CD4 in rural settings without laboratory services and biannual laboratory CD4 (LAB-CD4), biannual POC-CD4, and annual viral load in urban settings with laboratory services. We examine the impact of a range of values in sensitivity analyses, using Mozambique's 2014 per capita gross domestic product ($620) as a benchmark cost-effectiveness threshold. In rural settings, annual POC-CD4 compared to CLIN improves life expectancy by 2.8 years, reduces time on failed ART by 0.6 years, and yields an incremental cost-effectiveness ratio of $480/YLS. In urban settings, biannual POC-CD4 is more expensive and less effective than viral load. Compared to biannual LAB-CD4, viral load improves life expectancy by 0.6 years, reduces time on failed ART by 1.0 year, and is cost-effective ($440/YLS). In rural settings, annual POC-CD4 improves clinical outcomes and is cost-effective compared to CLIN. In urban settings, viral load has the greatest clinical benefit and is cost-effective compared to biannual POC-CD4 or LAB-CD4. Tailoring ART monitoring strategies to specific settings with different available resources can improve clinical outcomes while remaining economically efficient.

  6. Identification of unknown spatial load distributions in a vibrating Euler-Bernoulli beam from limited measured data

    NASA Astrophysics Data System (ADS)

    Hasanov, Alemdar; Kawano, Alexandre

    2016-05-01

    Two types of inverse source problems of identifying asynchronously distributed spatial loads governed by the Euler-Bernoulli beam equation ρ (x){w}{tt}+μ (x){w}t+{({EI}(x){w}{xx})}{xx}-{T}r{u}{xx}={\\sum }m=1M{g}m(t){f}m(x), (x,t)\\in {{{Ω }}}T := (0,l)× (0,T), with hinged-clamped ends (w(0,t)={w}{xx}(0,t)=0,w(l,t) = {w}x(l,t)=0,t\\in (0,T)), are studied. Here {g}m(t) are linearly independent functions, describing an asynchronous temporal loading, and {f}m(x) are the spatial load distributions. In the first identification problem the values {ν }k(t),k=\\bar{1,K}, of the deflection w(x,t), are assumed to be known, as measured output data, in a neighbourhood of the finite set of points P:= \\{{x}k\\in (0,l),k=\\bar{1,K}\\}\\subset (0,l), corresponding to the internal points of a continuous beam, for all t\\in ]0,T[. In the second identification problem the values {θ }k(t),k=\\bar{1,K}, of the slope {w}x(x,t), are assumed to be known, as measured output data in a neighbourhood of the same set of points P for all t\\in ]0,T[. These inverse source problems will be defined subsequently as the problems ISP1 and ISP2. The general purpose of this study is to develop mathematical concepts and tools that are capable of providing effective numerical algorithms for the numerical solution of the considered class of inverse problems. Note that both measured output data {ν }k(t) and {θ }k(t) contain random noise. In the first part of the study we prove that each measured output data {ν }k(t) and {θ }k(t),k=\\bar{1,K} can uniquely determine the unknown functions {f}m\\in {H}-1(]0,l[),m=\\bar{1,M}. In the second part of the study we will introduce the input-output operators {{ K }}d :{L}2(0,T)\\mapsto {L}2(0,T),({{ K }}df)(t):= w(x,t;f),x\\in P, f(x) := ({f}1(x),\\ldots ,{f}M(x)), and {{ K }}s :{L}2(0,T)\\mapsto {L}2(0,T), ({{ K }}sf)(t):= {w}x(x,t;f), x\\in P , corresponding to the problems ISP1 and ISP2, and then reformulate these problems as the operator equations: {{ K

  7. Secondary Engineering Design Graphics Educator Service Load of Students with Identified Categorical Disabilities and Limited English Proficiency

    ERIC Educational Resources Information Center

    Ernst, Jeremy V.; Li, Songze; Williams, Thomas O.

    2014-01-01

    The ever-changing student population of engineering design graphics students necessitates broader sets of instructor adeptness. Specifically, preparedness to educate and provide adequate educational access to content for students with identified categorical disabilities and Limited English Proficiency (LEP) is now an essential readiness skill for…

  8. Strategies for maintaining fruit quality in northern highbush blueberry under water limited conditions: Deficit irrigation and reduced crop loads

    USDA-ARS?s Scientific Manuscript database

    Many commercial blueberry (Vaccinium sp.) fields are irrigated, but mandatory water restrictions may soon limit the availability of irrigation water in several important blueberry growing regions such as California and eastern Washington. New strategies are needed to maintain fruit quality with less...

  9. Secondary Engineering Design Graphics Educator Service Load of Students with Identified Categorical Disabilities and Limited English Proficiency

    ERIC Educational Resources Information Center

    Ernst, Jeremy V.; Li, Songze; Williams, Thomas O.

    2014-01-01

    The ever-changing student population of engineering design graphics students necessitates broader sets of instructor adeptness. Specifically, preparedness to educate and provide adequate educational access to content for students with identified categorical disabilities and Limited English Proficiency (LEP) is now an essential readiness skill for…

  10. Limit case analysis of the "stable indenter velocity" method for obtaining creep stress exponents from constant load indentation creep tests

    NASA Astrophysics Data System (ADS)

    Campbell, J.; Dean, J.; Clyne, T. W.

    2017-02-01

    This study concerns a commonly-used procedure for evaluating the steady state creep stress exponent, n, from indentation data. The procedure involves monitoring the indenter displacement history under constant load and making the assumption that, once its velocity has stabilised, the system is in a quasi-steady state, with stage II creep dominating the behaviour. The stress and strain fields under the indenter are represented by "equivalent stress" and "equivalent strain rate" values. The estimate of n is then obtained as the gradient of a plot of the logarithm of the equivalent strain rate against the logarithm of the equivalent stress. Concerns have, however, been expressed about the reliability of this procedure, and indeed it has already been shown to be fundamentally flawed. In the present paper, it is demonstrated, using a very simple analysis, that, for a genuinely stable velocity, the procedure always leads to the same, constant value for n (either 1.0 or 0.5, depending on whether the tip shape is spherical or self-similar). This occurs irrespective of the value of the measured velocity, or indeed of any creep characteristic of the material. It is now clear that previously-measured values of n, obtained using this procedure, have varied in a more or less random fashion, depending on the functional form chosen to represent the displacement-time history and the experimental variables (tip shape and size, penetration depth, etc.), with little or no sensitivity to the true value of n.

  11. The influence of N load and harvest intensity on the risk of P limitation in Swedish forest soils.

    PubMed

    Akselsson, Cecilia; Westling, Olle; Alveteg, Mattias; Thelin, Gunnar; Fransson, Ann-Mari; Hellsten, Sofie

    2008-10-15

    Nitrogen (N) is often considered to be the major factor limiting tree growth in northern forest ecosystems. An increased N availability, however, increases the demand for other nutrients such as base cations and phosphorous (P) which in turn may change which nutrient is the limiting factor. If P or base cations become limiting, N will start to leach which means a risk of increased eutrophication of surface waters. As many studies focus on base cations, this study instead aims at estimating P budgets on a regional scale for different harvesting scenarios relevant for Swedish conditions. P budget calculations were carried out for 14,550 coniferous sites from the Swedish National Forest Inventory, as weathering+deposition-harvesting-leaching. Three scenarios with different harvest intensities were used: 1) no harvesting, 2) stem harvesting and 3) whole-tree harvesting. The input data were derived from measurements and model results. The P budget estimates indicate that harvesting, especially whole-tree harvesting, result in net losses of P in large parts of Sweden. The highest losses were found in southern Sweden due to high growth rate in this area. In the whole-tree harvesting scenario the losses exceeded 1 kg ha(-1) y(-1) on many sites. N budget calculations on the same sites indicate that N generally accumulates in the whole country and especially in the southern parts. Consequently, the N and P budget calculations indicate that the forests in southern Sweden are in a transition phase from N-to P-limitation to growth. This transition will proceed as long as the accumulation of N continues. These results are important in a sustainable forestry context, as a basis for assessing the risk of future N leaching, and in designing recommendations for abatement strategies of N deposition and for application of wood ash recycling and N fertilization.

  12. Cost-effectiveness of point-of-care viral load monitoring of ART in resource-limited settings: Mathematical modelling study

    PubMed Central

    ESTILL, Janne; EGGER, Matthias; BLASER, Nello; VIZCAYA, Luisa SALAZAR; GARONE, Daniela; WOOD, Robin; CAMPBELL, Jennifer; HALLETT, Timothy B.; KEISER, Olivia

    2013-01-01

    Background Monitoring of HIV viral load in patients on combination antiretroviral therapy (ART) is not generally available in resource-limited settings. We examined the cost-effectiveness of qualitative point-of-care viral load tests (POC-VL) in sub-Saharan Africa. Design Mathematical model based on longitudinal data from the Gugulethu and Khayelitsha township ART programmes in Cape Town, South Africa. Methods Cohorts of patients on ART monitored by POC-VL, CD4 cell count or clinically were simulated. Scenario A considered the more accurate detection of treatment failure with POC-VL only, Scenario B also considered the effect on HIV transmission. Scenario C further assumed that the risk of virologic failure is halved with POC-VL due to improved adherence. We estimated the change in costs per quality-adjusted life-year gained (incremental cost-effectiveness ratios, ICER) of POC-VL compared to CD4 and clinical monitoring. Results POC-VL tests with detection limits <1000 copies/ml increased costs due to unnecessary switches to second-line ART, without improving survival. Assuming POC-VL unit costs between US$5–US$20 and detection limits between 1000 and 10000 copies/ml, the ICER of POC-VL was US$4010–US$9230 compared to clinical and US$5960–US$25540 compared to CD4 monitoring. In Scenario B the corresponding ICERs were US$2450–US$5830 and US$2230–US$10380. In Scenario C the ICER ranged between US$960–US$2500 compared to clinical monitoring and between cost-saving and US$2460 compared to CD4 monitoring. Conclusions The cost-effectiveness of POC-VL for monitoring ART is improved by a higher detection limit, by taking the reduction in new HIV infections into account and when assuming that failure of first-line ART is reduced due to targeted adherence counselling. PMID:23462219

  13. Cost-effectiveness of point-of-care viral load monitoring of antiretroviral therapy in resource-limited settings: mathematical modelling study.

    PubMed

    Estill, Janne; Egger, Matthias; Blaser, Nello; Vizcaya, Luisa Salazar; Garone, Daniela; Wood, Robin; Campbell, Jennifer; Hallett, Timothy B; Keiser, Olivia

    2013-06-01

    Monitoring of HIV viral load in patients on combination antiretroviral therapy (ART) is not generally available in resource-limited settings. We examined the cost-effectiveness of qualitative point-of-care viral load tests (POC-VL) in sub-Saharan Africa. Mathematical model based on longitudinal data from the Gugulethu and Khayelitsha township ART programmes in Cape Town, South Africa. Cohorts of patients on ART monitored by POC-VL, CD4 cell count or clinically were simulated. Scenario A considered the more accurate detection of treatment failure with POC-VL only, and scenario B also considered the effect on HIV transmission. Scenario C further assumed that the risk of virologic failure is halved with POC-VL due to improved adherence. We estimated the change in costs per quality-adjusted life-year gained (incremental cost-effectiveness ratios, ICERs) of POC-VL compared with CD4 and clinical monitoring. POC-VL tests with detection limits less than 1000 copies/ml increased costs due to unnecessary switches to second-line ART, without improving survival. Assuming POC-VL unit costs between US$5 and US$20 and detection limits between 1000 and 10,000 copies/ml, the ICER of POC-VL was US$4010-US$9230 compared with clinical and US$5960-US$25540 compared with CD4 cell count monitoring. In Scenario B, the corresponding ICERs were US$2450-US$5830 and US$2230-US$10380. In Scenario C, the ICER ranged between US$960 and US$2500 compared with clinical monitoring and between cost-saving and US$2460 compared with CD4 monitoring. The cost-effectiveness of POC-VL for monitoring ART is improved by a higher detection limit, by taking the reduction in new HIV infections into account and assuming that failure of first-line ART is reduced due to targeted adherence counselling.

  14. Prevalence of low back disorders among female workers and biomechanical limits on the handling of load and patients.

    PubMed

    Gutiérrez, Manuel; Monzó, Jorge

    2012-01-01

    The purpose of this investigation was to determine the association between prevalence of low back disorders in female workers and biomechanical demands of compressive and shear forces at the lumbar spine. A descriptive, cross-sectional and correlational study was carried out in 11 groups of female workers in the Province of Concepción. An interview was performed to investigate the prevalence of low back pain. To estimate biomechanical demands on the lumbar spine, it was used the 3DSSPP software. The Pearson correlation coefficient between the prevalence of low back disorders and peak compression force at the lumbar spine was r = (p<0.005). The Spearman correlation coefficient between the prevalence of low back disorders and peak shear force was r = 0.9 (p <0.005). To protect 90% of female workers studied, the limits of compression and shear forces should be at 2.8 kN and 0.3 kN, respectively. These values differ from the recommendations currently used, 3.4 kN for peak compression force and 0.5 kN for peak shear force.

  15. Fuel and Core Design Options to Overcome the Heavy Metal Loading Limit and Improve Performance and Safety of Liquid Salt Cooled Reactors

    SciTech Connect

    Petrovic, Bojan; Maldonado, Ivan

    2016-04-14

    The research performed in this project addressed the issue of low heavy metal loading and the resulting reduced cycle length with increased refueling frequency, inherent to all FHR designs with solid, non-movable fuel based on TRISO particles. Studies performed here focused on AHTR type of reactor design with plate (“plank”) fuel. Proposal to FY12 NEUP entitled “Fuel and Core Design Options to Overcome the Heavy Metal Loading Limit and Improve Performance and Safety of Liquid Salt Cooled Reactors” was selected for award, and the 3-year project started in August 2012. A 4-month NCE was granted and the project completed on December 31, 2015. The project was performed by Georgia Tech (Prof. Bojan Petrovic, PI) and University of Tennessee (Prof. Ivan Maldonado, Co-PI), with a total funding of $758,000 over 3 years. In addition to two Co-PIs, the project directly engaged 6 graduate students (at doctoral or MS level) and 2 postdoctoral researchers. Additionally, through senior design projects and graduate advanced design projects, another 23 undergraduate and 12 graduate students were exposed to and trained in the salt reactor technology. We see this as one of the important indicators of the project’s success and effectiveness. In the process, 1 journal article was published (with 3 journal articles in preparation), together with 8 peer-reviewed full conference papers, 8 peer-reviewed extended abstracts, as well as 1 doctoral dissertation and 2 master theses. The work included both development of models and methodologies needed to adequately analyze this type of reactor, fuel, and its fuel cycle, as well as extensive analyses and optimization of the fuel and core design.

  16. Risk charts to guide targeted HIV-1 viral load monitoring of ART: development and validation in patients from resource-limited settings

    PubMed Central

    Koller, Manuel; Fatti, Geoffrey; Chi, Benjamin H; Keiser, Olivia; Hoffmann, Christopher J; Wood, Robin; Prozesky, Hans; Stinson, Kathryn; Giddy, Janet; Mutevedzi, Portia; Fox, Matthew; Law, Matthew; Boulle, Andrew; Egger, Matthias

    2017-01-01

    Background HIV-1 RNA viral load (VL) testing is recommended to monitor antiretroviral therapy (ART) but not available in many resource-limited settings. We developed and validated CD4-based risk charts to guide targeted VL testing. Methods We modeled the probability of virologic failure up to 5 years of ART based on current and baseline CD4 counts, developed decision rules for targeted VL testing of 10%, 20% or 40% of patients in seven cohorts of patients starting ART in South Africa, and plotted cut-offs for VL testing on colour-coded risk charts. We assessed the accuracy of risk chart-guided VL testing to detect virologic failure in validation cohorts from South Africa, Zambia and the Asia-Pacific. Findings 31,450 adult patients were included in the derivation and 25,294 patients in the validation cohorts. Positive predictive values increased with the percentage of patients tested: from 79% (10% tested) to 98% (40% tested) in the South African, from 64% to 93% in the Zambian and from 73% to 96% in the Asia-Pacific cohorts. Corresponding increases in sensitivity were from 35% to 68% in South Africa, from 55% to 82% in Zambia and from 37% to 71% in Asia-Pacific. The area under the receiver-operating curve increased from 0.75 to 0.91 in South Africa, from 0.76 to 0.91 in Zambia and from 0.77 to 0.92 in Asia Pacific. Interpretation CD4-based risk charts with optimal cut-offs for targeted VL testing may be useful to monitor ART in settings where VL capacity is limited. PMID:26470034

  17. Limit analysis of pipe clamps

    SciTech Connect

    Flanders, H.E. Jr.

    1990-01-01

    The Service Level D (faulted) load capacity of a conventional three-bolt pipe-clamp based upon the limit analysis method is presented. The load distribution, plastic hinge locations, and collapse load are developed for the lower bound limit load method. The results of the limit analysis are compared with the manufacturer's rated loads. 3 refs.

  18. Axial-Flow Turbine Rotor Discharge-Flow Overexpansion and Limit-Loading Condition, Part I: Computational Fluid Dynamics (CFD) Investigation

    NASA Technical Reports Server (NTRS)

    Chen, Shu-Cheng S.

    2017-01-01

    A Computational Fluid Dynamic (CFD) investigation is conducted over a two-dimensional axial-flow turbine rotor blade row to study the phenomena of turbine rotor discharge flow overexpansion at subcritical, critical, and supercritical conditions. Quantitative data of the mean-flow Mach numbers, mean-flow angles, the tangential blade pressure forces, the mean-flow mass flux, and the flow-path total pressure loss coefficients, averaged or integrated across the two-dimensional computational domain encompassing two blade-passages, are obtained over a series of 14 inlet-total to exit-static pressure ratios, from 1.5 (un-choked; subcritical condition) to 10.0 (supercritical with excessively high pressure ratio.) Detailed flow features over the full domain-of-computation, such as the streamline patterns, Mach contours, pressure contours, blade surface pressure distributions, etc. are collected and displayed in this paper. A formal, quantitative definition of the limit loading condition based on the channel flow theory is proposed and explained. Contrary to the comments made in the historical works performed on this subject, about the deficiency of the theoretical methods applied in analyzing this phenomena, using modern CFD method for the study of this subject appears to be quite adequate and successful. This paper describes the CFD work and its findings.

  19. Experimental Investigation of Spark-Ignited Combustion with High-Octane Biofuels and EGR. 2. Fuel and EGR Effects on Knock-Limited Load and Speed

    SciTech Connect

    Splitter, Derek A; Szybist, James P

    2013-01-01

    The present study experimentally investigates spark-ignited combustion with 87 AKI E0 gasoline in its neat form and in midlevel alcohol gasoline blends with 24% vol/vol isobutanol gasoline (IB24) and 30% vol/vol ethanol gasoline (E30). A single-cylinder research engine is used with an 11.85:1 compression ratio, hydraulically actuated valves, laboratory intake air, and was capable of external exhaust gas recirculation (EGR). Experiments were conducted with all fuels to full-load conditions with = 1, using both 0% and 15% external-cooled EGR. Higher octane number biofuel blends exhibited increased stoichiometric torque capability at this compression ratio, where the unique properties of ethanol enabled a doubling of the stoichiometric torque capability with E30 as compared to that of 87AKI, up to 20 bar IMEPg (indicating mean effective pressure gross) at = 1. The results demonstrate that for all fuels, EGR is a key enabler for increasing engine efficiency but is less useful for knock mitigation with E30 than for 87AKI gasoline or IB24. Under knocking conditions, 15% EGR is found to offer 1 CA of CA50 timing advance with E30, whereas up to 5 CA of CA50 advance is possible with knock-limited 87AKI gasoline. Compared to 87AKI, both E30 and IB24 are found to have reduced adiabatic flame temperature and shorter combustion durations, which reduce knocking propensity beyond that indicated by the octane number. However, E30+0% EGR is found to exhibit the better antiknock properties than either 87AKI+15% EGR or IB24+15% EGR, expanding the knock limited operating range and engine stoichiometric torque capability at high compression ratio. Furthermore, the fuel sensitivity (S) of E30 was attributed to reduced speed sensitivity of E30, expanding the low-speed stoichiometric torque capability at high compression ratio. The results illustrate that intermediate alcohol gasoline blends exhibit exceptional antiknock properties and performance beyond that indicated by the octane

  20. Some load limits and self-lubricating properties of plain spherical bearings with molded graphite fiber reinforced polyimide liners to 320 C

    NASA Technical Reports Server (NTRS)

    Sliney, H. E.

    1978-01-01

    Plain spherical bearings with molded liners of self-lubricating graphite fiber-polyimide composite were developed and their dynamic load capacities were determined. Liners were prepared by transfer molding a prepolymer resin-fiber mix into the space between the ball and outer race, the completing polymerization under heat and pressure. Bearing dynamic load capacities were in excess of 140 MPa (20,000 psi) from room temperature to 260 C and about 70 MPa (10,000 psi) at 320 C. Friction coefficients were about 0.20 at room temperatures and light loads and tended to decrease with increasing temperatures and loads to about 0.15. Thermal expansion of the liner at uniform bearing temperatures of 200 C or higher produced a bearing preload which could be alleviated by providing an initial internal diametral clearance of 0.05 to 0.10 mm.

  1. Should viral load thresholds be lowered?: Revisiting the WHO definition for virologic failure in patients on antiretroviral therapy in resource-limited settings.

    PubMed

    Labhardt, Niklaus D; Bader, Joëlle; Lejone, Thabo Ishmael; Ringera, Isaac; Hobbins, Michael A; Fritz, Christiane; Ehmer, Jochen; Cerutti, Bernard; Puga, Daniel; Klimkait, Thomas

    2016-07-01

    The World Health Organization (WHO) guidelines on antiretroviral therapy (ART) define treatment failure as 2 consecutive viral loads (VLs) ≥1000 copies/mL. There is, however, little evidence supporting 1000 copies as an optimal threshold to define treatment failure. Objective of this study was to assess the correlation of the WHO definition with the presence of drug-resistance mutations in patients who present with 2 consecutive unsuppressed VL in a resource-limited setting.In 10 nurse-led clinics in rural Lesotho children and adults on first-line ART for ≥6 months received a first routine VL. Those with plasma VL ≥80 copies/mL were enrolled in a prospective study, receiving enhanced adherence counseling (EAC) and a follow-up VL after 3 months. After a second unsuppressed VL genotypic resistance testing was performed. Viruses with major mutations against ≥2 drugs of the current regimen were classified as "resistant".A total of 1563 adults and 191 children received a first routine VL. Of the 138 adults and 53 children with unsuppressed VL (≥80 copies/mL), 165 (116 adults; 49 children) had a follow-up VL after EAC; 108 (74 adults; 34 children) remained unsuppressed and resistance testing was successful. Ninety of them fulfilled the WHO definition of treatment failure (both VL ≥1000 copies/mL); for another 18 both VL were unsuppressed but with <1000 copies/mL. The positive predictive value (PPV) for the WHO failure definition was 81.1% (73/90) for the presence of resistant virus. Among the 18 with VL levels between 80 and 1000 copies/mL, thereby classified as "non-failures", 17 (94.4%) harbored resistant viruses. Lowering the VL threshold from 1000 copies/mL to 80 copies/mL at both determinations had no negative influence on the PPV (83.3%; 90/108).The current WHO-definition misclassifies patients who harbor resistant virus at VL below 1000 c/mL as "nonfailing." Lowering the threshold to VL ≥80 copies/mL identifies a significantly

  2. Effect on transmission of HIV-1 resistance of timing of implementation of viral load monitoring to determine switches from first to second-line antiretroviral regimens in resource-limited settings.

    PubMed

    Phillips, Andrew N; Pillay, Deenan; Garnett, Geoff; Bennett, Diane; Vitoria, Marco; Cambiano, Valentina; Lundgren, Jens

    2011-03-27

    There is concern that antiretroviral therapy (ART) use with only clinical monitoring for failure will result in high rates of transmission of virus with resistance to drugs currently in use. A stochastic simulation model of transmission of HIV, natural history and the effect of ART, was developed and used to predict the proportion of new infections with resistance according to whether and when viral load monitoring is introduced. In our base model, there was predicted to be 12.4% of new HIV infections with primary antiretroviral resistance in 2020 if clinical monitoring is used throughout, compared with 5.4 and 6.1% if viral load-guided switching (based on viral load measured every 6 months, with switch determined by a value >500 copies/ml) was introduced in 2010 or 2015, respectively. The death rate for those on ART was lowest when viral load monitoring was used, but the overall death rate in all infected people was higher if viral load monitoring was introduced at the expense of scale-up in HIV diagnosis and ART initiation beyond their 2010 coverage levels (4.7 compared with 3.1 per 100 person-years). To preserve current first-line drugs for the long term there is an eventual need for some form of cheap and practical viral load monitoring in resource-limited settings. However, a delay in introduction of 5 years has limited consequences for resistance transmission so the current priority for countries' ART programmes is to increase HIV testing and provide treatment for all those in need of ART.

  3. Load cell

    DOEpatents

    Spletzer, Barry L.

    2001-01-01

    A load cell combines the outputs of a plurality of strain gauges to measure components of an applied load. Combination of strain gauge outputs allows measurement of any of six load components without requiring complex machining or mechanical linkages to isolate load components. An example six axis load cell produces six independent analog outputs which can be combined to determine any one of the six general load components.

  4. Load cell

    DOEpatents

    Spletzer, Barry L.

    1998-01-01

    A load cell combines the outputs of a plurality of strain gauges to measure components of an applied load. Combination of strain gauge outputs allows measurement of any of six load components without requiring complex machining or mechanical linkages to isolate load components. An example six axis load cell produces six independent analog outputs, each directly proportional to one of the six general load components.

  5. Limit analysis of pipe clamps. Revision 1

    SciTech Connect

    Flanders, H.E. Jr.

    1990-12-31

    The Service Level D (faulted) load capacity of a conventional three-bolt pipe-clamp based upon the limit analysis method is presented. The load distribution, plastic hinge locations, and collapse load are developed for the lower bound limit load method. The results of the limit analysis are compared with the manufacturer`s rated loads. 3 refs.

  6. [To consider negative viral loads below the limit of quantification can lead to errors in the diagnosis and treatment of hepatitis C virus infection].

    PubMed

    Acero Fernández, Doroteo; Ferri Iglesias, María José; López Nuñez, Carme; Louvrie Freire, René; Aldeguer Manté, Xavier

    2013-01-01

    For years many clinical laboratories have routinely classified undetectable and unquantifiable levels of hepatitis C virus RNA (HCV-RNA) determined by RT-PCR as below limit of quantification (BLOQ). This practice might result in erroneous clinical decisions. To assess the frequency and clinical relevance of assuming that samples that are BLOQ are negative. We performed a retrospective analysis of RNA determinations performed between 2009 and 2011 (Cobas/Taqman, lower LOQ: 15 IU/ml). We distinguished between samples classified as «undetectable» and those classified as «<1.50E+01IU/mL» (BLOQ). We analyzed 2.432 HCV-RNA measurements in 1.371 patients. RNA was BLOQ in 26 samples (1.07%) from 23 patients (1.68%). BLOQ results were highly prevalent among patients receiving Peg-Riba: 23 of 216 samples (10.6%) from 20 of 88 patients receiving treatment (22.7%). The clinical impact of BLOQ RNA samples was as follows: a) 2 patients initially considered to have negative results subsequently showed quantifiable RNA; b) 8 of 9 patients (88.9%) with BLOQ RNA at week 4 of treatment later showed sustained viral response; c) 3 patients with BLOQ RNA at weeks 12 and 48 of treatment relapsed; d) 4 patients with BLOQ RNA at week 24 and/or later had partial or breakthrough treatment responses, and e) in 5 patients the impact were null or could not be ascertained. This study suggests that BLOQ HCV-RNA indicates viremia and that equating a BLOQ result with a negative result can lead to treatment errors. BLOQ results are highly prevalent in on-treatment patients. The results of HCV-RNA quantification should be classified clearly, distinguishing between undetectable levels and levels that are BLOQ. Copyright © 2013 Elsevier España, S.L. and AEEH y AEG. All rights reserved.

  7. Anaerobic co-digestion of cheese whey and the screened liquid fraction of dairy manure in a single continuously stirred tank reactor process: Limits in co-substrate ratios and organic loading rate.

    PubMed

    Rico, Carlos; Muñoz, Noelia; Rico, José Luis

    2015-01-01

    Mesophilic anaerobic co-digestion of cheese whey and the screened liquid fraction of dairy manure was investigated with the aim of determining the treatment limits in terms of the cheese whey fraction in feed and the organic loading rate. The results of a continuous stirred tank reactor that was operated with a hydraulic retention time of 15.6 days showed that the co-digestion process was possible with a cheese whey fraction as high as 85% in the feed. The efficiency of the process was similar within the range of the 15-85% cheese whey fraction. To study the effect of the increasing loading rate, the HRT was progressively shortened with the 65% cheese whey fraction in the feed. The reactor efficiency dropped as the HRT decreased but enabled a stable operation over 8.7 days of HRT. At these operating conditions, a volumetric methane production rate of 1.37 m(3) CH4 m(-3) d(-1) was achieved.

  8. Human Crashworthiness and Crash Load Limits

    DTIC Science & Technology

    1988-12-01

    Analytical Mtnoaa and aodal» can provlda a neans of ralating a ganaral body exposure to a specific susceptible body structura and» given the appropriate...strength properties of the local structure, allow praoiction of tallura/lnjuty of that particular structura . Proa an anglnaarlng point this 1* a

  9. Local load shedding

    SciTech Connect

    Adibi, M.M.; Thorne, D.K. )

    1988-08-01

    Equipment overloads in an underground transmission network are caused by unscheduled outages. Repairs or replacements of damaged cables and/or transformers in urban areas are inherently difficult and time-consuming. Therefore, for overloads greatly in excess of short-time ratings, speed of load shedding is of paramount importance. Under such conditions, the system operator is faced with: recognizing the problem, determining the course of action and shedding the correct amount of load at the right locations. These tasks are difficult to perform, particularly under pressure of time. Reliance on pre-specified load shedding lists is not satisfactory since the load shedding lists do not necessarily match the amounts and locations of the required loads to be shed. Clearly, there has been a need for a local load shedding scheme, which in the first order of importance, would relieve the overloaded equipment within the time limits imposed by the equipment short-time ratings and in the second order of importance, would ''minimize'' the amount of load to be curtailed. This paper describes an approach which meets the dual objective, providing a practical solution to a difficult engineering/operating problem.

  10. Force Limit System

    NASA Technical Reports Server (NTRS)

    Pawlik, Ralph; Krause, David; Bremenour, Frank

    2011-01-01

    The Force Limit System (FLS) was developed to protect test specimens from inadvertent overload. The load limit value is fully adjustable by the operator and works independently of the test system control as a mechanical (non-electrical) device. When a test specimen is loaded via an electromechanical or hydraulic test system, a chance of an overload condition exists. An overload applied to a specimen could result in irreparable damage to the specimen and/or fixturing. The FLS restricts the maximum load that an actuator can apply to a test specimen. When testing limited-run test articles or using very expensive fixtures, the use of such a device is highly recommended. Test setups typically use electronic peak protection, which can be the source of overload due to malfunctioning components or the inability to react quickly enough to load spikes. The FLS works independently of the electronic overload protection.

  11. 14 CFR 25.1531 - Maneuvering flight load factors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maneuvering flight load factors. 25.1531... Operating Limitations § 25.1531 Maneuvering flight load factors. Load factor limitations, not exceeding the positive limit load factors determined from the maneuvering diagram in § 25.333(b), must be established. ...

  12. 14 CFR 25.1531 - Maneuvering flight load factors.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maneuvering flight load factors. 25.1531... Operating Limitations § 25.1531 Maneuvering flight load factors. Load factor limitations, not exceeding the positive limit load factors determined from the maneuvering diagram in § 25.333(b), must be established. ...

  13. Use of Flexible Body Coupled Loads in Assessment of Day of Launch Flight Loads

    NASA Technical Reports Server (NTRS)

    Starr, Brett R.; Yunis, Isam; Olds, Aaron D.

    2011-01-01

    A Day of Launch flight loads assessment technique that determines running loads calculated from flexible body coupled loads was developed for the Ares I-X Flight Test Vehicle. The technique was developed to quantify DOL flight loads in terms of structural load components rather than the typically used q-alpha metric to provide more insight into the DOL loads. In this technique, running loads in the primary structure are determined from the combination of quasi-static aerodynamic loads and dynamic loads. The aerodynamic loads are calculated as a function of time using trajectory parameters passed from the DOL trajectory simulation and are combined with precalculated dynamic loads using a load combination equation. The potential change in aerodynamic load due to wind variability during the countdown is included in the load combination. In the event of a load limit exceedance, the technique allows the identification of what load component is exceeded, a quantification of how much the load limit is exceeded, and where on the vehicle the exceedance occurs. This technique was used to clear the Ares I-X FTV for launch on October 28, 2009. This paper describes the use of coupled loads in the Ares I-X flight loads assessment and summarizes the Ares I-X load assessment results.

  14. Lumbosacral loads in bedmaking.

    PubMed

    Milburn, P D; Barrett, R S

    1999-06-01

    The purpose of this study was to determine whether the introduction of larger and heavier beds which were lower to the floor increased the physical stress on employees responsible for room cleaning and bedmaking in the hospitality industry. More specifically, this study assessed the effect of bed size (single, double and king) and bed height (460 and 560 mm) on dynamic and static estimates of L5/S1 compression force and static L5/S1 shear force for six simulated components of the overall bedmaking task. Results confirmed the view that static models severely underestimate the loads on the lumbar spine under inertial lifting conditions, and also indicated that: (i) tasks with the greatest hand loads were not necessarily associated with the greatest spinal loads due to differences in the way each task was performed; (ii) L5/S1 loads produced during bedmaking may exceed recommended safe lifting limits for certain task-size height combinations; and (iii) the use of larger and heavier beds in the hospitality industry imposes increased loads on the lumbar spine. The investigation of alternative work practices designed to minimise loads on the lumbar spine is recommended.

  15. LOADING DEVICE

    DOEpatents

    Ohlinger, L.A.

    1958-10-01

    A device is presented for loading or charging bodies of fissionable material into a reactor. This device consists of a car, mounted on tracks, into which the fissionable materials may be placed at a remote area, transported to the reactor, and inserted without danger to the operating personnel. The car has mounted on it a heavily shielded magazine for holding a number of the radioactive bodies. The magazine is of a U-shaped configuration and is inclined to the horizontal plane, with a cap covering the elevated open end, and a remotely operated plunger at the lower, closed end. After the fissionable bodies are loaded in the magazine and transported to the reactor, the plunger inserts the body at the lower end of the magazine into the reactor, then is withdrawn, thereby allowing gravity to roll the remaining bodies into position for successive loading in a similar manner.

  16. Speed limits of aircraft

    NASA Technical Reports Server (NTRS)

    Everling, E

    1923-01-01

    This paper is restricted to the question of attainable speed limits and attacks the problem from different angles. Theoretical limits due to air resistance are presented along with design factors which may affect speed such as wing loads, wing areas, wing section shifting, landing speeds, drag-lift ratios, and power coefficients.

  17. Carbohydrate Loading.

    ERIC Educational Resources Information Center

    Csernus, Marilyn

    Carbohydrate loading is a frequently used technique to improve performance by altering an athlete's diet. The objective is to increase glycogen stored in muscles for use in prolonged strenuous exercise. For two to three days, the athlete consumes a diet that is low in carbohydrates and high in fat and protein while continuing to exercise and…

  18. Carbohydrate Loading.

    ERIC Educational Resources Information Center

    Csernus, Marilyn

    Carbohydrate loading is a frequently used technique to improve performance by altering an athlete's diet. The objective is to increase glycogen stored in muscles for use in prolonged strenuous exercise. For two to three days, the athlete consumes a diet that is low in carbohydrates and high in fat and protein while continuing to exercise and…

  19. 14 CFR 23.726 - Ground load dynamic tests.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Landing Gear § 23.726 Ground load dynamic tests. (a) If compliance with the ground load requirements of...); or (2) Sufficient to develop 1.5 times the limit load factor. (b) The critical landing condition...

  20. 14 CFR 23.726 - Ground load dynamic tests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Landing Gear § 23.726 Ground load dynamic tests. (a) If compliance with the ground load requirements of...); or (2) Sufficient to develop 1.5 times the limit load factor. (b) The critical landing condition...

  1. Shuttle car loading system

    NASA Technical Reports Server (NTRS)

    Collins, E. R., Jr. (Inventor)

    1985-01-01

    A system is described for loading newly mined material such as coal, into a shuttle car, at a location near the mine face where there is only a limited height available for a loading system. The system includes a storage bin having several telescoping bin sections and a shuttle car having a bottom wall that can move under the bin. With the bin in an extended position and filled with coal the bin sections can be telescoped to allow the coal to drop out of the bin sections and into the shuttle car, to quickly load the car. The bin sections can then be extended, so they can be slowly filled with more while waiting another shuttle car.

  2. KENNEDY SPACE CENTER, FLA. - Japanese astronaut Koichi Wakata looks at the spars installed on the wing of the orbiter Atlantis. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing via the spars - a series of floating joints - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

    NASA Image and Video Library

    2003-09-05

    KENNEDY SPACE CENTER, FLA. - Japanese astronaut Koichi Wakata looks at the spars installed on the wing of the orbiter Atlantis. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing via the spars - a series of floating joints - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

  3. LOADED WAVEGUIDES

    DOEpatents

    Mullett, L.B.; Loach, B.G.; Adams, G.L.

    1958-06-24

    >Loaded waveguides are described for the propagation of electromagnetic waves with reduced phase velocities. A rectangular waveguide is dimensioned so as to cut-off the simple H/sub 01/ mode at the operating frequency. The waveguide is capacitance loaded, so as to reduce the phase velocity of the transmitted wave, by connecting an electrical conductor between directly opposite points in the major median plane on the narrower pair of waveguide walls. This conductor may take a corrugated shape or be an aperature member, the important factor being that the electrical length of the conductor is greater than one-half wavelength at the operating frequency. Prepared for the Second U.N. International ConferThe importance of nuclear standards is duscussed. A brief review of the international callaboration in this field is given. The proposal is made to let the International Organization for Standardization (ISO) coordinate the efforts from other groups. (W.D.M.)

  4. Limits to Open Class Performance?

    NASA Technical Reports Server (NTRS)

    Bowers, Albion H.

    2008-01-01

    This presentation discusses open or unlimited class aircraft performance limitations and design solutions. Limitations in this class of aircraft include slow climbing flight which requires low wing loading, high cruise speed which requires high wing loading, gains in induced or viscous drag alone which result in only half the gain overall and other structural problems (yaw inertia and spins, flutter and static loads integrity). Design solutions include introducing minimum induced drag for a given span (elliptical span load or winglets) and introducing minimum induced drag for a bell shaped span load. It is concluded that open class performance limits (under current rules and technologies) is very close to absolute limits, though some gains remain to be made from unexplored areas and new technologies.

  5. Load management

    NASA Astrophysics Data System (ADS)

    Moir, Ian

    The development of the Electrical Load Management System (ELMS) for the Boeing 777 aircraft is reviewed. The discussion covers the overall design of the system, its principal components, and the functions it provides. Some of the additional system drivers, such as autoland electrical system partitioning and dispatch reliability, are outlined, and their effect on the system architecture is examined. The key technologies used in the development of the ELMS include smart high power contactors, ARING 629 data buses, the Motorola 68020 processor combined with Ada software, dedicated ASICs, and modular architecture for improved maintainability.

  6. 14 CFR 27.473 - Ground loading conditions and assumptions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... through the center of gravity throughout the landing impact. This lift may not exceed two-thirds of the... rotorcraft must be designed for a limit load factor of not less than the limit inertia load...

  7. Structural assessment of accident loads

    SciTech Connect

    Wagenblast, G.R., Westinghouse Hanford

    1996-05-28

    Structural assessments were made for specific accident loads for specific catch, receiver, and storage tanks. The evaluation herein represents level-of-effort order-of-magnitude estimates of limiting loads that would lead to collapse or rupture of the tank and unmitigated loss of confinement for the waste. Structural capacities were established using failure criteria. Compliance with codes such as ACI, ASCE, ASME, RCRA, UBC, WAC, and DOE Orders was `NOT` maintained. Normal code practice is to prevent failure with margins consistent with expected variations in loads and strengths and confidence in analysis techniques. The evaluation herein represent estimates of code limits without code load factors or code strength reduction factors, and loading beyond such a limit is considered as an onset of some failure mode. The exact nature of the failure mode and its relation to a safe condition is a judgment of the analyst. Consequently, these `RESULTS SHALL NOT BE USED TO ESTABLISH OPERATING OR SAFETY LOAD LIMITS FOR THESE TANKS`.

  8. Ratcheting caused by moving loads

    NASA Astrophysics Data System (ADS)

    Hübel, Hartwig; Vollrath, Bastian

    2017-06-01

    Progressive deformation (ratcheting) can occur as a response to variable loads as soon as the elastic limit is exceeded. If this is the case, strains and displacements accumulate in the event of cyclic loading in each load cycle. Widely known as triggers for ratcheting and already being considered in some design codes are configurations, in which a structure is subjected to at least two different types of load, namely a constant load (the primary load) and a superimposed cyclic load. In this paper, another mechanism that generates ratcheting is introduced. It can be attributed solely to the effect of a single load. In the simplest case, this can be explained by the successive activation of (an infinite number of) plastic hinges if a load of constant magnitude is moved in space. The increments of strains and displacements can decrease or increase from cycle to cycle, when the material is hardening, or if elastic foundation is present, or if the equilibrium condition is formulated for the deformed system (second-order theory) or if "large" rotations are taken into account (third-order theory).

  9. Load regulating latch

    NASA Technical Reports Server (NTRS)

    Appleberry, W. T. (Inventor)

    1977-01-01

    A load regulating mechanical latch is described that has a pivotally mounted latch element having a hook-shaped end with a strike roller-engaging laterally open hook for engaging a stationary strike roller. The latch element or hook is pivotally mounted in a clevis end of an elongated latch stem that is adapted for axial movement through an opening in a support plate or bracket mounted to a structural member. A coil spring is disposed over and around the extending latch stem and the lower end of the coil spring engages the support bracket. A thrust washer is removably attached to the other end of the latch stem and engages the other end of the coil spring and compresses the coil spring thereby preloading the spring and the latch element carried by the latch stem. The hook-shaped latch element has a limited degree of axial travel for loading caused by structural distortion which may change the relative positions of the latch element hook and the strike roller. Means are also provided to permit limited tilt of the latch element due to loading of the hook.

  10. 14 CFR 125.383 - Load manifest.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... airplane; (3) The maximum allowable takeoff and landing weights for that flight; (4) The center of gravity limits; (5) The center of gravity of the loaded airplane, except that the actual center of gravity need... that ensures that the center of gravity of the loaded airplane is within approved limits. In those...

  11. 14 CFR 125.383 - Load manifest.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... airplane; (3) The maximum allowable takeoff and landing weights for that flight; (4) The center of gravity limits; (5) The center of gravity of the loaded airplane, except that the actual center of gravity need... that ensures that the center of gravity of the loaded airplane is within approved limits. In those...

  12. 14 CFR 125.383 - Load manifest.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... airplane; (3) The maximum allowable takeoff and landing weights for that flight; (4) The center of gravity limits; (5) The center of gravity of the loaded airplane, except that the actual center of gravity need... that ensures that the center of gravity of the loaded airplane is within approved limits. In those...

  13. 14 CFR 125.383 - Load manifest.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... airplane; (3) The maximum allowable takeoff and landing weights for that flight; (4) The center of gravity limits; (5) The center of gravity of the loaded airplane, except that the actual center of gravity need... that ensures that the center of gravity of the loaded airplane is within approved limits. In those...

  14. 14 CFR 125.383 - Load manifest.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... airplane; (3) The maximum allowable takeoff and landing weights for that flight; (4) The center of gravity limits; (5) The center of gravity of the loaded airplane, except that the actual center of gravity need... that ensures that the center of gravity of the loaded airplane is within approved limits. In those...

  15. Application of expert system to load composition rate estimation algorithm

    SciTech Connect

    Lim, J.Y.; Kim, J.H.; Kim, J.O.; Singh, C.

    1999-08-01

    A load model is needed for the power system analysis including load flow and stability studies. The load model representation needs the load composition rate indicating the portion of several typical load groups. This paper proposes a refined load composition rate estimation algorithm with input data which are relative coefficients, limit values, and the energy portion of load groups. An expert system is constructed with the consideration of the uncertainty of input data. The load composition rates in several customers in the power system are obtained and the results of case studies show that a reasonable load composition rate is achieved.

  16. National Launch System cycle 1 loads and models data book

    NASA Technical Reports Server (NTRS)

    Bugg, F.; Brunty, J.; Ernsberger, G.; Mcghee, D.; Gagliano, L.; Harrington, F.; Meyer, D.; Blades, E.

    1992-01-01

    This document contains preliminary cycle 1 loads for the National Launch System (NLS) 1 and 2 vehicles. The loads provided and recommended as design loads represent the maximum load expected during prelaunch and flight regimes, i.e., limit loads, except that propellant tank ullage pressure has not been included. Ullage pressure should be added to the loads book values for cases where the addition results in higher loads. The loads must be multiplied by the appropriate factors of safety to determine the ultimate loads for which the structure must be capable.

  17. Expression of Sucrose Transporter cDNAs Specifically in Companion Cells Enhances Phloem Loading and Long-Distance Transport of Sucrose but Leads to an Inhibition of Growth and the Perception of a Phosphate Limitation1[W][OPEN

    PubMed Central

    Dasgupta, Kasturi; Khadilkar, Aswad S.; Sulpice, Ronan; Pant, Bikram; Scheible, Wolf-Rüdiger; Fisahn, Joachim; Stitt, Mark; Ayre, Brian G.

    2014-01-01

    Sucrose (Suc) is the predominant form of carbon transported through the phloem from source to sink organs and is also a prominent sugar for short-distance transport. In all streptophytes analyzed, Suc transporter genes (SUTs or SUCs) form small families, with different subgroups evolving distinct functions. To gain insight into their capacity for moving Suc in planta, representative members of each clade were first expressed specifically in companion cells of Arabidopsis (Arabidopsis thaliana) and tested for their ability to rescue the phloem-loading defect caused by the Suc transporter mutation, Atsuc2-4. Sequence similarity was a poor indicator of ability: Several genes with high homology to AtSUC2, some of which have phloem-loading functions in other eudicot species, did not rescue the Atsuc2-4 mutation, whereas a more distantly related gene, ZmSUT1 from the monocot Zea mays, did restore phloem loading. Transporter complementary DNAs were also expressed in the companion cells of wild-type Arabidopsis, with the aim of increasing productivity by enhancing Suc transport to growing sink organs and reducing Suc-mediated feedback inhibition on photosynthesis. Although enhanced Suc loading and long-distance transport was achieved, growth was diminished. This growth inhibition was accompanied by increased expression of phosphate (P) starvation-induced genes and was reversed by providing a higher supply of external P. These experiments suggest that efforts to increase productivity by enhancing sugar transport may disrupt the carbon-to-P homeostasis. A model for how the plant perceives and responds to changes in the carbon-to-P balance is presented. PMID:24777345

  18. Genetic selection for fast growth generates bone architecture characterised by enhanced periosteal expansion and limited consolidation of the cortices but a diminution in the early responses to mechanical loading.

    PubMed

    Rawlinson, Simon C F; Murray, Dianne H; Mosley, John R; Wright, Chris D P; Bredl, John C; Saxon, Leanne K; Loveridge, Nigel; Leterrier, Christine; Constantin, Paul; Farquharson, Colin; Pitsillides, Andrew A

    2009-08-01

    Bone strength is, in part, dependent on a mechanical input that regulates the (re)modelling of skeletal elements to an appropriate size and architecture to resist fracture during habitual use. The rate of longitudinal bone growth in juveniles can also affect fracture incidence in adulthood, suggesting an influence of growth rate on later bone quality. We have compared the effects of fast and slow growth on bone strength and architecture in the tibiotarsi of embryonic and juvenile birds. The loading-related biochemical responses (intracellular G6PD activity and NO release) to mechanical load were also determined. Further, we have analysed the proliferation and differentiation characteristics of primary tibiotarsal osteoblasts from fast and slow-growing strains. We found that bones from chicks with divergent growth rates display equal resistance to applied loads, but weight-correction revealed that the bones from juvenile fast growth birds are weaker, with reduced stiffness and lower resistance to fracture. Primary osteoblasts from slow-growing juvenile birds proliferated more rapidly and had lower alkaline phosphatase activity. Bones from fast-growing embryonic chicks display rapid radial expansion and incomplete osteonal infilling but, importantly, lack mechanical responsiveness. These findings are further evidence that the ability to respond to mechanical inputs is crucial to adapt skeletal architecture to generate a functionally appropriate bone structure and that fast embryonic and juvenile growth rates may predispose bone to particular architectures with increased fragility in the adult.

  19. The DEMO wall load challenge

    NASA Astrophysics Data System (ADS)

    Wenninger, R.; Albanese, R.; Ambrosino, R.; Arbeiter, F.; Aubert, J.; Bachmann, C.; Barbato, L.; Barrett, T.; Beckers, M.; Biel, W.; Boccaccini, L.; Carralero, D.; Coster, D.; Eich, T.; Fasoli, A.; Federici, G.; Firdaouss, M.; Graves, J.; Horacek, J.; Kovari, M.; Lanthaler, S.; Loschiavo, V.; Lowry, C.; Lux, H.; Maddaluno, G.; Maviglia, F.; Mitteau, R.; Neu, R.; Pfefferle, D.; Schmid, K.; Siccinio, M.; Sieglin, B.; Silva, C.; Snicker, A.; Subba, F.; Varje, J.; Zohm, H.

    2017-04-01

    For several reasons the challenge to keep the loads to the first wall within engineering limits is substantially higher in DEMO compared to ITER. Therefore the pre-conceptual design development for DEMO that is currently ongoing in Europe needs to be based on load estimates that are derived employing the most recent plasma edge physics knowledge. An initial assessment of the static wall heat load limit in DEMO infers that the steady state peak heat flux limit on the majority of the DEMO first wall should not be assumed to be higher than 1.0 MW m‑2. This compares to an average wall heat load of 0.29 MW m‑2 for the design {\\tt {EU}}{\\tt {~}}{\\tt {DEMO1}}{\\tt {~2015}} assuming a perfect homogeneous distribution. The main part of this publication concentrates on the development of first DEMO estimates for charged particle, radiation, fast particle (all static) and disruption heat loads. Employing an initial engineering wall design with clear optimization potential in combination with parameters for the flat-top phase (x-point configuration), loads up to 7 MW m‑2 (penalty factor for tolerances etc not applied) have been calculated. Assuming a fraction of power radiated from the x-point region between 1/5 and 1/3, peaks of the total power flux density due to radiation of 0.6–0.8 MW m‑2 are found in the outer baffle region. This first review of wall loads, and the associated limits in DEMO clearly underlines a significant challenge that necessitates substantial engineering efforts as well as a considerable consolidation of the associated physics basis.

  20. Loads Combination Research at Marshall Space Flight Center

    NASA Technical Reports Server (NTRS)

    Ferebee, R.

    2000-01-01

    This is the result of a study conducted by the Structural Dynamics Division of the Marshall Space Flight Center concerning the combination of low- and high-frequency dynamic loads for spacecraft design. Low-frequency transient loads are combined with high frequency acoustically induced loads to arrive at a limit load, for design purposes. Different methods are used for combining the loads which can lead to considerable variation in limit loads, depending on which NASA Center did the calculation. This study investigates several different combination methods and compares the combination methods with Spacelab 1 flight data. In addition, the relative timing of low- and high-frequency loads is examined.

  1. Reliability analysis of RC containment structures under combined loads

    SciTech Connect

    Hwang, H.; Reich, M.; Kagami, S.

    1984-01-01

    This paper discusses a reliability analysis method and load combination design criteria for reinforced concrete containment structures under combined loads. The probability based reliability analysis method is briefly described. For load combination design criteria, derivations of the load factors for accidental pressure due to a design basis accident and safe shutdown earthquake (SSE) for three target limit state probabilities are presented.

  2. 14 CFR 25.391 - Control surface loads: General.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Control surface loads: General. 25.391... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Control Surface and System Loads § 25.391 Control surface loads: General. The control surfaces must be designed for the limit loads...

  3. 14 CFR 25.391 - Control surface loads: General.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Control surface loads: General. 25.391... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Control Surface and System Loads § 25.391 Control surface loads: General. The control surfaces must be designed for the limit loads...

  4. 14 CFR 25.391 - Control surface loads: General.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Control surface loads: General. 25.391... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Control Surface and System Loads § 25.391 Control surface loads: General. The control surfaces must be designed for the limit loads...

  5. 14 CFR 25.391 - Control surface loads: General.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Control surface loads: General. 25.391... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Control Surface and System Loads § 25.391 Control surface loads: General. The control surfaces must be designed for the limit loads...

  6. Structural load control during construction

    NASA Astrophysics Data System (ADS)

    Mikulas, Martin

    The topics are presented in viewgraph form and include the following: examples of high transient loadings on large space structures; energy absorbing/load limiting strut research objectives; scope of research on energy absorbing struts to date; energy characteristics of cantilevered trusses with a tip load; ten bay long resilient truss example; stored energy characteristics of one meter deep truss; energy absorbing potential for 10-bay 5-meter deep truss; schematic of energy absorbing strut; linear load and motion control actuator; rigid body response of a solar array to the shuttle thruster pressure impingement; solar array piecewise linear response; solar array characteristics; solar array tip deflection and required actuator stroke; solar array response from finite element analysis; 12 bay energy absorbing test bed dynamics; and new AERO-Lab with 12-bay test beam.

  7. Essentials of filoviral load quantification.

    PubMed

    Cnops, Lieselotte; van Griensven, Johan; Honko, Anna N; Bausch, Daniel G; Sprecher, Armand; Hill, Charles E; Colebunders, Robert; Johnson, Joshua C; Griffiths, Anthony; Palacios, Gustavo F; Kraft, Colleen S; Kobinger, Gary; Hewlett, Angela; Norwood, David A; Sabeti, Pardis; Jahrling, Peter B; Formenty, Pierre; Kuhn, Jens H; Ariën, Kevin K

    2016-07-01

    Quantitative measurement of viral load is an important parameter in the management of filovirus disease outbreaks because viral load correlates with severity of disease, survival, and infectivity. During the ongoing Ebola virus disease outbreak in parts of Western Africa, most assays used in the detection of Ebola virus disease by more than 44 diagnostic laboratories yielded qualitative results. Regulatory hurdles involved in validating quantitative assays and the urgent need for a rapid Ebola virus disease diagnosis precluded development of validated quantitative assays during the outbreak. Because of sparse quantitative data obtained from these outbreaks, opportunities for study of correlations between patient outcome, changes in viral load during the course of an outbreak, disease course in asymptomatic individuals, and the potential for virus transmission between infected patients and contacts have been limited. We strongly urge the continued development of quantitative viral load assays to carefully evaluate these parameters in future outbreaks of filovirus disease.

  8. 14 CFR 25.1531 - Maneuvering flight load factors.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Maneuvering flight load factors. 25.1531 Section 25.1531 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Operating Limitations § 25.1531 Maneuvering flight load factors. Load factor limitations, not exceeding the...

  9. 14 CFR 25.1531 - Maneuvering flight load factors.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Maneuvering flight load factors. 25.1531 Section 25.1531 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Operating Limitations § 25.1531 Maneuvering flight load factors. Load factor limitations, not exceeding the...

  10. 14 CFR 25.511 - Ground load: unsymmetrical loads on multiple-wheel units.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... landing gear units are assumed to be subjected to the limit ground loads prescribed in this subpart under... inflated. The distribution of the limit loads among the wheels of the landing gear must be established for... factors: (1) The number of wheels and their physical arrangements. For truck type landing gear units,...

  11. Optical Limiting.

    DTIC Science & Technology

    1992-05-22

    AGENCY USE ONLY (Leave EPO RT D A TE 3. REPORT TYPE AND DATES COVERED 4. TITLE AND SUBTITLE S. FUNDING NUMBERS Optical Limiting 6. AUTHOR(S) , 1 oS...to nanoseconds and find that, since the excited state absorption is cummulative, that the dyes can limit well for nanosecond pulses but not for...over which the device limits . In addition, we find that the dynamic range of limiting devices can be substantially increased using two elements without

  12. 24 CFR 3280.401 - Structural load tests.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... set in § 3280.305(d), rupture, fracture, or excessive yielding. Design live load deflection criteria... live load deflection greater than the limits set in § 3280.305(d), rupture, fracture, or excessive...

  13. 24 CFR 3280.401 - Structural load tests.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... set in § 3280.305(d), rupture, fracture, or excessive yielding. Design live load deflection criteria... live load deflection greater than the limits set in § 3280.305(d), rupture, fracture, or...

  14. 24 CFR 3280.401 - Structural load tests.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... set in § 3280.305(d), rupture, fracture, or excessive yielding. Design live load deflection criteria... live load deflection greater than the limits set in § 3280.305(d), rupture, fracture, or...

  15. Current limiters

    SciTech Connect

    Loescher, D.H.; Noren, K.

    1996-09-01

    The current that flows between the electrical test equipment and the nuclear explosive must be limited to safe levels during electrical tests conducted on nuclear explosives at the DOE Pantex facility. The safest way to limit the current is to use batteries that can provide only acceptably low current into a short circuit; unfortunately this is not always possible. When it is not possible, current limiters, along with other design features, are used to limit the current. Three types of current limiters, the fuse blower, the resistor limiter, and the MOSFET-pass-transistor limiters, are used extensively in Pantex test equipment. Detailed failure mode and effects analyses were conducted on these limiters. Two other types of limiters were also analyzed. It was found that there is no best type of limiter that should be used in all applications. The fuse blower has advantages when many circuits must be monitored, a low insertion voltage drop is important, and size and weight must be kept low. However, this limiter has many failure modes that can lead to the loss of over current protection. The resistor limiter is simple and inexpensive, but is normally usable only on circuits for which the nominal current is less than a few tens of milliamperes. The MOSFET limiter can be used on high current circuits, but it has a number of single point failure modes that can lead to a loss of protective action. Because bad component placement or poor wire routing can defeat any limiter, placement and routing must be designed carefully and documented thoroughly.

  16. Perceptual Load Modulates Object-Based Attention

    ERIC Educational Resources Information Center

    Ho, Ming-Chou; Atchley, Paul

    2009-01-01

    Two experimental series are reported using both reaction time (RT) and a data-limited perceptual report to examine the effects of perceptual load on object-based attention. Perceptual load was manipulated across 3 levels by increasing the complexity of perceptual judgments. Data from the RT-based experiments showed object-based effects when the…

  17. Helicopter Fatigue Load and Life Determination Methods

    DTIC Science & Technology

    1975-08-01

    Coy, George J. Roth DAAJO2-74-C-0031 9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT. PROJECT. TASK _ UiAREA & WOK UNIT NUMBERS...23 Transformation of Data Points to Endurance Values . 24 Statistics of Transformed Stresses ......... 27 Endurance Limit Stress for...29 Illustrated Loading Distribution .... .......... .. 37 Duplicate Flight Record Distributions .......... ... 37 Ś Stress vs Load Level

  18. Maximizing TDRS Command Load Lifetime

    NASA Technical Reports Server (NTRS)

    Brown, Aaron J.

    2002-01-01

    The GNC software onboard ISS utilizes TORS command loads, and a simplistic model of TORS orbital motion to generate onboard TORS state vectors. Each TORS command load contains five "invariant" orbital elements which serve as inputs to the onboard propagation algorithm. These elements include semi-major axis, inclination, time of last ascending node crossing, right ascension of ascending node, and mean motion. Running parallel to the onboard software is the TORS Command Builder Tool application, located in the JSC Mission Control Center. The TORS Command Builder Tool is responsible for building the TORS command loads using a ground TORS state vector, mirroring the onboard propagation algorithm, and assessing the fidelity of current TORS command loads onboard ISS. The tool works by extracting a ground state vector at a given time from a current TORS ephemeris, and then calculating the corresponding "onboard" TORS state vector at the same time using the current onboard TORS command load. The tool then performs a comparison between these two vectors and displays the relative differences in the command builder tool GUI. If the RSS position difference between these two vectors exceeds the tolerable lim its, a new command load is built using the ground state vector and uplinked to ISS. A command load's lifetime is therefore defined as the time from when a command load is built to the time the RSS position difference exceeds the tolerable limit. From the outset of TORS command load operations (STS-98), command load lifetime was limited to approximately one week due to the simplicity of both the onboard propagation algorithm, and the algorithm used by the command builder tool to generate the invariant orbital elements. It was soon desired to extend command load lifetime in order to minimize potential risk due to frequent ISS commanding. Initial studies indicated that command load lifetime was most sensitive to changes in mean motion. Finding a suitable value for mean motion

  19. Voltage controller/current limiter for ac

    NASA Technical Reports Server (NTRS)

    Wu, T. T.

    1980-01-01

    Circuit protects ac power systems for overload failures, limits power surge and short-circuit currents to 150 percent of steady state level, regulates ac output voltage, and soft starts loads. Limiter generates dc error signal in response to line fluctuations and dumps power when overload is reached. Device is inserted between ac source and load.

  20. PLT rotating pumped limiter

    SciTech Connect

    Cohen, S.A.; Budny, R.V.; Corso, V.; Boychuck, J.; Grisham, L.; Heifetz, D.; Hosea, J.; Luyber, S.; Loprest, P.; Manos, D.

    1984-07-01

    A limiter with a specially contoured front face and the ability to rotate during tokamak discharges has been installed in a PLT pump duct. These features have been selected to handle the unique particle removal and heat load requirements of ICRF heating and lower-hybrid current-drive experiments. The limiter has been conditioned and commissioned in an ion-beam test stand by irradiation with 1 MW power, 200 ms duration beams of 40 keV hydrogen ions. Operation in PLT during ohmic discharges has proven the ability of the limiter to reduce localized heating caused by energetic electron bombardment and to remove about 2% of the ions lost to the PLT walls and limiters.

  1. Adaptive limit margin detection and limit avoidance

    NASA Astrophysics Data System (ADS)

    Yavrucuk, Ilkay

    This thesis concerns the development of methods, algorithms, and control laws for the development of an adaptive flight envelope protection system to be used for both manned and unmanned aircraft. The proposed method lifts the requirement for detailed a priori information of aircraft dynamics by enabling adaptation to system uncertainty. The system can be used for limits that can be either measured or related to selected measurable quantities. Specifically, an adaptive technique for predicting limit margins and calculating the corresponding allowable control or controller command margins of an aircraft is described in an effort to enable true carefree maneuvering. This new approach utilizes adaptive neural network based loops for the approximation of required aircraft dynamics. For limits that reach their maximum value in steady state, a constructed estimator model is used to predict the maneuvering quasi-steady response behavior---the so called dynamic trim---of the limit parameters and the corresponding control or command margins. Linearly Parameterized Neural Networks as well as Single Hidden Layer Neural Networks are used for on-line adaptation. The approach does not require any off-line training of the neural networks, instead all learning is achieved during flight. Lyapunov based weight update laws are derived. The method is extended for multi-channelled control limiting for aircraft subject to multiple limits, and for automatic control and command limiting for UAV's. Simulation evaluations of the method using a linear helicopter model and a nonlinear Generalized Tiltrotor Simulation (GTRSIM) model are presented. Limit avoidance methods are integrated and tested through the implementation of an artificial pilot model and an active-stick controller model for tactile cueing in the tiltrotor simulation, GTRSIM. Load factor, angle-of-attack, and torque limits are considered as examples. Similarly, the method is applied to the Georgia Tech's Yamaha R-Max (GTMax

  2. Concurrent working memory load can facilitate selective attention: evidence for specialized load.

    PubMed

    Park, Soojin; Kim, Min-Shik; Chun, Marvin M

    2007-10-01

    Load theory predicts that concurrent working memory load impairs selective attention and increases distractor interference (N. Lavie, A. Hirst, J. W. de Fockert, & E. Viding). Here, the authors present new evidence that the type of concurrent working memory load determines whether load impairs selective attention or not. Working memory load was paired with a same/different matching task that required focusing on targets while ignoring distractors. When working memory items shared the same limited-capacity processing mechanisms with targets in the matching task, distractor interference increased. However, when working memory items shared processing with distractors in the matching task, distractor interference decreased, facilitating target selection. A specialized load account is proposed to describe the dissociable effects of working memory load on selective processing depending on whether the load overlaps with targets or with distractors.

  3. 46 CFR 153.806 - Loading information.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Testing and... enables the master to load and ballast the tankship while keeping structural stresses within design limits. ...

  4. 46 CFR 153.806 - Loading information.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Testing and... enables the master to load and ballast the tankship while keeping structural stresses within design limits. ...

  5. 46 CFR 153.806 - Loading information.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Testing and... enables the master to load and ballast the tankship while keeping structural stresses within design limits. ...

  6. Truss-core corrugation for compressive loads

    NASA Technical Reports Server (NTRS)

    Davis, Randall C. (Inventor); Jackson, Robert (Inventor)

    1988-01-01

    A corrugated panel structure for supporting compressive loads is described which includes curved cap strips separated by truss-core web segments. The truss-core web segments are formed from first and second flat panels with a corrugated filler in between them. The corrugated filler extends in the direction of the compressive load. As a result, all components of the panel structure have a compressive load carrying capability resulting in a high strength-to-weight ratio when the compressive load is limiting. Application to rocket and aircraft structures is suggested.

  7. Truss-core corrugation for compressive loads

    NASA Astrophysics Data System (ADS)

    Davis, Randall C.; Jackson, Robert

    1988-09-01

    A corrugated panel structure for supporting compressive loads is described which includes curved cap strips separated by truss-core web segments. The truss-core web segments are formed from first and second flat panels with a corrugated filler in between them. The corrugated filler extends in the direction of the compressive load. As a result, all components of the panel structure have a compressive load carrying capability resulting in a high strength-to-weight ratio when the compressive load is limiting. Application to rocket and aircraft structures is suggested.

  8. Updates on Force Limiting Improvements

    NASA Technical Reports Server (NTRS)

    Kolaini, Ali R.; Scharton, Terry

    2013-01-01

    The following conventional force limiting methods currently practiced in deriving force limiting specifications assume one-dimensional translation source and load apparent masses: Simple TDOF model; Semi-empirical force limits; Apparent mass, etc.; Impedance method. Uncorrelated motion of the mounting points for components mounted on panels and correlated, but out-of-phase, motions of the support structures are important and should be considered in deriving force limiting specifications. In this presentation "rock-n-roll" motions of the components supported by panels, which leads to a more realistic force limiting specifications are discussed.

  9. Updates on Force Limiting Improvements

    NASA Technical Reports Server (NTRS)

    Kolaini, Ali R.; Scharton, Terry

    2013-01-01

    The following conventional force limiting methods currently practiced in deriving force limiting specifications assume one-dimensional translation source and load apparent masses: Simple TDOF model; Semi-empirical force limits; Apparent mass, etc.; Impedance method. Uncorrelated motion of the mounting points for components mounted on panels and correlated, but out-of-phase, motions of the support structures are important and should be considered in deriving force limiting specifications. In this presentation "rock-n-roll" motions of the components supported by panels, which leads to a more realistic force limiting specifications are discussed.

  10. Fatigue failure load indicator

    NASA Technical Reports Server (NTRS)

    Imig, L. A.; Davis, W. T.; Davis, D. C. (Inventor)

    1979-01-01

    An indicator for recording the load at which a fatigue specimen breaks during the last cycle of a fatigue test is described. A load cell is attached to the specimen which is alternately subjected to tension and compression loads. The output of the load cell which is proportional to the load on the specimen is applied to the input of a peak detector. Each time the specimen is subjected to a compression load, means are provided for applying a positive voltage to the rest of the peak detector to reset it. During the last cycle of the tension load the peak detector measures the maximum load on the specimen. Means are provided for disconnecting the load cell from the peak detector when there is a failure in the specimen.

  11. 14 CFR 25.1583 - Operating limitations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... distribution. The weight and center of gravity limitations established under § 25.1519 must be furnished in the... weight and center of gravity limits, and to maintain the loading within these limits in flight. (3) If certification for more than one center of gravity range is requested, the appropriate limitations, with regard...

  12. Wash load and bed-material load transport in the Yellow River

    USGS Publications Warehouse

    Yang, C.T.; Simoes, F.J.M.

    2005-01-01

    It has been the conventional assumption that wash load is supply limited and is only indirectly related to the hydraulics of a river. Hydraulic engineers also assumed that bed-material load concentration is independent of wash load concentration. This paper provides a detailed analysis of the Yellow River sediment transport data to determine whether the above assumptions are true and whether wash load concentration can be computed from the original unit stream power formula and the modified unit stream power formula for sediment-laden flows. A systematic and thorough analysis of 1,160 sets of data collected from 9 gauging stations along the Middle and Lower Yellow River confirmed that the method suggested by the conjunctive use of the two formulas can be used to compute wash load, bed-material load, and total load in the Yellow River with accuracy. Journal of Hydraulic Engineering ?? ASCE.

  13. The Hugoniot Elastic Limit Decay Limit

    NASA Astrophysics Data System (ADS)

    Billingsley, J. P.

    1997-07-01

    The Hugoniot Elastic Limit(HEL) precursor decay in shock loaded solids has been the subject of considerable experimental and theoretical investigation. Comparative evidence is presented to show that the elastic precursor wave particle velocity, UPHEL, for certain materials decays asymptotically with propagation distance to the DeBroglie velocity, V1, level. This is demonstrated for the following materials: iron, aluminum alloy 6061-T6, plexiglas(PMMA), nickel alloy(MAR-M200), and lithium flouride(LiF). The DeBroglie velocity, V1, equals h/2md, where h is Planck's Constant, m is the mass of one atom, and d is the closest distance between atoms. Thus a relationship has been established between a microscopically derived velocity, V1, and a macroscopically observed velocity, UPHEL.

  14. Load sensing system

    DOEpatents

    Sohns, Carl W.; Nodine, Robert N.; Wallace, Steven Allen

    1999-01-01

    A load sensing system inexpensively monitors the weight and temperature of stored nuclear material for long periods of time in widely variable environments. The system can include an electrostatic load cell that encodes weight and temperature into a digital signal which is sent to a remote monitor via a coaxial cable. The same cable is used to supply the load cell with power. When multiple load cells are used, vast

  15. Taking a Load Off.

    ERIC Educational Resources Information Center

    Kenny, John

    1995-01-01

    Discusses the snow -load capacity of school roofs and how understanding this data aids in planning preventive measures and easing fear of roof collapse. Describes how to determine snow-load capacity, and explains the load-bearing behavior of flat versus sloped roofs. Collapse prevention measures are highlighted. (GR)

  16. On Limits

    NASA Technical Reports Server (NTRS)

    Holzmann, Gerard J.

    2008-01-01

    In the last 3 decades or so, the size of systems we have been able to verify formally with automated tools has increased dramatically. At each point in this development, we encountered a different set of limits -- many of which we were eventually able to overcome. Today, we may have reached some limits that may be much harder to conquer. The problem I will discuss is the following: given a hypothetical machine with infinite memory that is seamlessly shared among infinitely many CPUs (or CPU cores), what is the largest problem size that we could solve?

  17. 29 CFR 1919.77 - Safe working load increase.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Safe working load increase. 1919.77 Section 1919.77 Labor... load increase. (a) In no case shall safe working loads be increased beyond the manufacturer's ratings or original design limitations unless such increase meets with the manufacturer's approval. Where the...

  18. 14 CFR 25.343 - Design fuel and oil loads.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Design fuel and oil loads. 25.343 Section 25.343 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... the wing at limit loads corresponding to— (i) A maneuvering load factor of +2.25; and (ii) The...

  19. Optimization of Nanowire-Resistance Load Logic Inverter.

    PubMed

    Hashim, Yasir; Sidek, Othman

    2015-09-01

    This study is the first to demonstrate characteristics optimization of nanowire resistance load inverter. Noise margins and inflection voltage of transfer characteristics are used as limiting factors in this optimization. Results indicate that optimization depends on resistance value. Increasing of load resistor tends to increasing in noise margins until saturation point, increasing load resistor after this point will not improve noise margins significantly.

  20. 14 CFR 25.391 - Control surface loads: General.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Control surface loads: General. 25.391... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Control Surface and System Loads § 25.391 Control surface loads: General. The control surfaces must be designed for the limit...

  1. Optimal Control Allocation with Load Sensor Feedback for Active Load Suppression

    NASA Technical Reports Server (NTRS)

    Miller, Christopher

    2017-01-01

    These slide sets describe the OCLA formulation and associated algorithms as a set of new technologies in the first practical application of load limiting flight control utilizing load feedback as a primary control measurement. Slide set one describes Experiment Development and slide set two describes Flight-Test Performance.

  2. 14 CFR 25.511 - Ground load: unsymmetrical loads on multiple-wheel units.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... differential equal to 2/3 of the most unfavorable combination of diameter variations that is obtained when... tires— (1) The applied side or drag load factor, or both factors, at the center of gravity must be the most critical value up to 50 percent and 40 percent, respectively, of the limit side or drag load...

  3. Optimal Control Allocation with Load Sensor Feedback for Active Load Suppression

    NASA Technical Reports Server (NTRS)

    Miller, Christopher

    2017-01-01

    These slide sets describe the OCLA formulation and associated algorithms as a set of new technologies in the first practical application of load limiting flight control utilizing load feedback as a primary control measurement. Slide set one describes Experiment Development and slide set two describes Flight-Test Performance.

  4. Behaviour of glass plates under wind loads

    NASA Astrophysics Data System (ADS)

    Gavanski, Eri

    Glazing damage during strong windstorms has been considered to result mainly from windborne debris. However, recent windstorm damage reports have revealed the necessity of studying fluctuating wind loads, which appear to be another factor contributing to this damage. From an experimental point of view, studies on this topic have been limited to the application of rather simple loading patterns. Moreover, there is an uncertainty surrounding both load resistance and design load used in the current North American window glass design codes. It is of concern that these regulations may not offer sufficient accuracy on account of the limited understanding of time-dependent glass strength derived from the technology available at the time of codification. Unprecedented full-scale glass breakage tests under realistic wind pressure loading were conducted to investigate these issues. The obtained results revealed significant new information about the behavior of glass plates under fluctuating loads. Along with these tests, a numerical simulation using the Monte-Carlo technique was also performed with a subtle modification of the initial glass strength. This adjustment resulted in better correspondence with test results. Using the test and numerical simulation results, the current window glass design method was examined. The calculation methods of LR, and the reference time conversion used in the codes, were found to require further investigation. By creating a particular wind pressure time history, the practice of using peak pressures from ASCE7-05 as the design load was investigated. The results showed that there are cases when the current practice may underestimate the design load because of the duration of windstorms. KEYWORDS: Glass, Fluctuating load, Full-scale test, Load resistance, Design load, Static fatigue, Numerical simulation, Monte-Carlo technique, Brown's integral.

  5. Symplastic phloem loading in poplar.

    PubMed

    Zhang, Cankui; Han, Lu; Slewinski, Thomas L; Sun, Jianlei; Zhang, Jing; Wang, Zeng-Yu; Turgeon, Robert

    2014-09-01

    Sap is driven through phloem sieve tubes by an osmotically generated pressure gradient between source and sink tissues. In many plants, source pressure results from thermodynamically active loading in which energy is used to transfer sucrose (Suc) from mesophyll cells to the phloem of leaf minor veins against a concentration gradient. However, in some species, almost all trees, correlative evidence suggests that sugar migrates passively through plasmodesmata from mesophyll cells into the sieve elements. The possibility of alternate loading mechanisms has important ramifications for the regulation of phloem transport and source-sink interactions. Here, we provide experimental evidence that, in gray poplar (Populus tremula × Populus alba), Suc enters the phloem through plasmodesmata. Transgenic plants were generated with yeast invertase in the cell walls to prevent Suc loading by this route. The constructs were driven either by the constitutive 35S promoter or the minor vein-specific galactinol synthase promoter. Transgenic plants grew at the same rate as the wild type without symptoms of loading inhibition, such as accumulation of carbohydrates or leaf chlorosis. Rates of photosynthesis were normal. In contrast, alfalfa (Medicago sativa) plants, which have limited numbers of plasmodesmata between mesophyll and phloem, displayed typical symptoms of loading inhibition when transformed with the same DNA constructs. The results are consistent with passive loading of Suc through plasmodesmata in poplar. We also noted defense-related symptoms in leaves of transgenic poplar when the plants were abruptly exposed to excessively high temperatures, adding to evidence that hexose is involved in triggering the hypersensitive response.

  6. Load Induced Blindness

    PubMed Central

    Macdonald, James S. P.; Lavie, Nilli

    2008-01-01

    Although the perceptual load theory of attention has stimulated a great deal of research, evidence for the role of perceptual load in determining perception has typically relied on indirect measures that infer perception from distractor effects on reaction times or neural activity (see N. Lavie, 2005d`) was consistently reduced with high, compared to low, perceptual load but was unaffected by the level of working memory load. Because alternative accounts in terms of expectation, memory, response bias, and goal-neglect due to the more strenuous high load task were ruled out, these experiments clearly demonstrate that high perceptual load determines conscious perception, impairing the ability to merely detect the presence of a stimulus—a phenomenon of load induced blindness. PMID:18823196

  7. Load Model Data Tool

    SciTech Connect

    David Chassin, Pavel Etingov

    2013-04-30

    The LMDT software automates the process of the load composite model data preparation in the format supported by the major power system software vendors (GE and Siemens). Proper representation of the load composite model in power system dynamic analysis is very important. Software tools for power system simulation like GE PSLF and Siemens PSSE already include algorithms for the load composite modeling. However, these tools require that the input information on composite load to be provided in custom formats. Preparation of this data is time consuming and requires multiple manual operations. The LMDT software enables to automate this process. Software is designed to generate composite load model data. It uses the default load composition data, motor information, and bus information as an input. Software processes the input information and produces load composition model. Generated model can be stored in .dyd format supported by GE PSLF package or .dyr format supported by Siemens PSSE package.

  8. Mutational load analysis of unrelated individuals

    PubMed Central

    2011-01-01

    Evolutionary genetic models predict that the cumulative effect of rare deleterious mutations across the genome—known as mutational load burden—increases the susceptibility to complex disease. To test the mutational load burden hypothesis, we adopted a two-tiered approach: assessing the impact of whole-exome minor allele load burden and then conducting individual-gene screening. For our primary analysis, we examined various minor allele frequency (MAF) thresholds and weighting schemes to examine the overall effect of minor allele load on affection status. We found a consistent association between minor allele load and affection status, but this effect did not markedly increase within rare and/or functional single-nucleotide polymorphisms (SNPs). Our follow-up analysis considered minor allele load in individual genes to see whether only one or a few genes were driving the overall effect. Examining our most significant result—minor allele load of nonsynonymous SNPs with MAF < 2.4%—we detected no significantly associated genes after Bonferroni correction for multiple testing. After moderately significant genes (p < 0.05) were removed, the overall effect of rare nonsynonymous allele load remained significant. Overall, we did not find clear support for mutational load burden on affection status; however, these results are ultimately dependent on and limited by the nature of the Genetic Analysis Workshop 17 simulation. PMID:22373138

  9. Detection limit

    SciTech Connect

    Porter, P.S.; Ward, R.C.; Bell, H.F.

    1988-08-01

    Water quality monitoring data are plagued with levels of chemicals that are too low to be measured precisely. This discussion will focus on the information needs of water quality management and how these needs are best met for monitoring systems that require many trace-level measurements. We propose that the limit of detection (LOD) or the limit of quantitation (LOQ) not be used to censor data. Although LOD and LOQ aid in the interpretation of individual measurements, they hinder statistical analysis of water quality data. More information is gained when a numerical result and an estimate of measurement precision are reported for every measurement, as opposed to reporting not detected or less than. This article is not intended to be a review of the issues pertaining to the LOD and related concepts.

  10. Electric Power Load Analysis (EPLA) for Surface Ships

    DTIC Science & Technology

    2012-09-17

    b. Air operation for aircraft carriers. c. Debarking operation for cargo and amphibious warfare ships. DDS 310-1 REV 1 7 d. Replenishment-at-sea...carrier. Emergency ship control and the larger electrical load associate with selected weapons or limited air operations (recovery and strike down of...operating load to the connected load of the equipment. If the load is intermittent or cyclic, such as an air compressor motor, the factor shall be selected

  11. Combined mechanical loading of composite tubes

    NASA Technical Reports Server (NTRS)

    Derstine, Mark S.; Pindera, Marek-Jerzy; Bowles, David E.

    1988-01-01

    An analytical/experimental investigation was performed to study the effect of material nonlinearities on the response of composite tubes subjected to combined axial and torsional loading. The effect of residual stresses on subsequent mechanical response was included in the investigation. Experiments were performed on P75/934 graphite-epoxy tubes with a stacking sequence of (15/0/ + or - 10/0/ -15), using pure torsion and combined axial/torsional loading. In the presence of residual stresses, the analytical model predicted a reduction in the initial shear modulus. Experimentally, coupling between axial loading and shear strain was observed in laminated tubes under combined loading. The phenomenon was predicted by the nonlinear analytical model. The experimentally observed linear limit of the global shear response was found to correspond to the analytically predicted first ply failure. Further, the failure of the tubes was found to be path dependent above a critical load level.

  12. 46 CFR 45.179 - Cargo limitations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Cargo limitations. 45.179 Section 45.179 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES Unmanned River... cargoes, even in drums or tank containers, may not be carried. (b) Hazardous materials, as defined in part...

  13. 46 CFR 45.179 - Cargo limitations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Cargo limitations. 45.179 Section 45.179 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES Unmanned River... cargoes, even in drums or tank containers, may not be carried. (b) Hazardous materials, as defined in part...

  14. Inducer Hydrodynamic Load Measurement Devices

    NASA Technical Reports Server (NTRS)

    Skelley, Stephen E.; Zoladz, Thomas F.

    2002-01-01

    Marshall Space Flight Center (MSFC) has demonstrated two measurement devices for sensing and resolving the hydrodynamic loads on fluid machinery. The first - a derivative of the six component wind tunnel balance - senses the forces and moments on the rotating device through a weakened shaft section instrumented with a series of strain gauges. This "rotating balance" was designed to directly measure the steady and unsteady hydrodynamic loads on an inducer, thereby defining both the amplitude and frequency content associated with operating in various cavitation modes. The second device - a high frequency response pressure transducer surface mounted on a rotating component - was merely an extension of existing technology for application in water. MSFC has recently completed experimental evaluations of both the rotating balance and surface-mount transducers in a water test loop. The measurement bandwidth of the rotating balance was severely limited by the relative flexibility of the device itself, resulting in an unexpectedly low structural bending mode and invalidating the higher frequency response data. Despite these limitations, measurements confirmed that the integrated loads on the four-bladed inducer respond to both cavitation intensity and cavitation phenomena. Likewise, the surface-mount pressure transducers were subjected to a range of temperatures and flow conditions in a non-rotating environment to record bias shifts and transfer functions between the transducers and a reference device. The pressure transducer static performance was within manufacturer's specifications and dynamic response accurately followed that of the reference.

  15. Inducer Hydrodynamic Load Measurement Devices

    NASA Technical Reports Server (NTRS)

    Skelley, Stephen E.; Zoladz, Thomas F.; Turner, Jim (Technical Monitor)

    2002-01-01

    Marshall Space Flight Center (MSFC) has demonstrated two measurement devices for sensing and resolving the hydrodynamic loads on fluid machinery. The first - a derivative of the six-component wind tunnel balance - senses the forces and moments on the rotating device through a weakened shaft section instrumented with a series of strain gauges. This rotating balance was designed to directly measure the steady and unsteady hydrodynamic loads on an inducer, thereby defining both the amplitude and frequency content associated with operating in various cavitation modes. The second device - a high frequency response pressure transducer surface mounted on a rotating component - was merely an extension of existing technology for application in water. MSFC has recently completed experimental evaluations of both the rotating balance and surface-mount transducers in a water test loop. The measurement bandwidth of the rotating balance was severely limited by the relative flexibility of the device itself, resulting in an unexpectedly low structural bending mode and invalidating the higher-frequency response data. Despite these limitations, measurements confirmed that the integrated loads on the four-bladed inducer respond to both cavitation intensity and cavitation phenomena. Likewise, the surface-mount pressure transducers were subjected to a range of temperatures and flow conditions in a non-rotating environment to record bias shifts and transfer functions between the transducers and a reference device. The pressure transducer static performance was within manufacturer's specifications and dynamic response accurately followed that of the reference.

  16. Phalange Tactile Load Cell

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Diftler, Myron A. (Inventor); Linn, Douglas Martin (Inventor); Platt, Robert (Inventor); Griffith, Bryan Kristian (Inventor)

    2010-01-01

    A tactile load cell that has particular application for measuring the load on a phalange in a dexterous robot system. The load cell includes a flexible strain element having first and second end portions that can be used to mount the load cell to the phalange and a center portion that can be used to mount a suitable contact surface to the load cell. The strain element also includes a first S-shaped member including at least three sections connected to the first end portion and the center portion and a second S-shaped member including at least three sections coupled to the second end portion and the center portion. The load cell also includes eight strain gauge pairs where each strain gauge pair is mounted to opposing surfaces of one of the sections of the S-shaped members where the strain gauge pairs provide strain measurements in six-degrees of freedom.

  17. Aircraft subfloor response to crash loadings

    NASA Technical Reports Server (NTRS)

    Carden, H. D.; Hayduk, R. J.

    1981-01-01

    Results are presented of an experimental and analytical study of the dynamic response to crash loadings of five different load-limiting subfloors for general aviation aircraft. These subfloors provide a high-strength structural floor platform to retain the seats and a crushable zone to absorb energy and limit vertical loads. Experimental static load-deflection data and dynamic deceleration response data for the five subfloors indicated that the high-strength floor platform performed well in that structural integrity and residual strength was maintained throughout the loading cycle. The data also indicated that some of the subfloor crush zones were more effective than others in providing nearly constant load for a range of displacement. The analytical data was generated by characterizing the nonlinear crush zones of the subfloor with static load-deflection data and using the DYCAST nonlinear finite element computer program. Comparisons between experimental and analytical data showed good correlation for the subfloors in which the static deformation mode closely approximated the dynamic deformation mode.

  18. Loads Limits Values of Soils with Petroleum Hydrocarbons

    NASA Astrophysics Data System (ADS)

    Dumitru, Mihail; Vladimirescu, Andreea

    2017-04-01

    The high demand for oil and associated products as a source of energy, resulting in increased oil exploitation, producing, refining, transportation, storage, marketing and use led to high levels of environmental pollution. The optimum bioremediation variant proved to be the one in which fertilizer (potassium humate in NPK matrix with microelements and 8% monosaccharides) applied in a 650 l/ha dose was used together with the Zeba absorbent in 32 kg/ha dose, where the TPH level dropped by 58% in 45 days from the pollution with 3% crude oil. Most of these areas are affected by historical pollution. Many organic contaminants may undergo an ongoing process in the soil, whereby over time contaminant become less and less subject to decomposition even though relatively can still be detected in the laboratory analyses. In Romania about 50.000 ha are polluted with oil and/or brine. The bioremediation was the main method of rehabilitation. The Regulation on the assessment of environmental pollution, the following are presented as guide values for total oil hydrocarbons content in soil: - normal: less than 100 mg/kg; - alert values for sensitive soils: 200 mg/kg; - alert values for less sensitive soils: 1000 mg/kg; - intervention values for sensitive soils: 500 mg/kg; - intervention values for less sensitive soils: 2000 mg/kg. Researches done in laboratory monitored the effect of various concentrations of oil (under 2000 mg/kg, 3000 mg/kg, 5000 mg/kg, 7000 mg/kg, 10 000 mg/kg) on germination of wheat seeds at 5 and 7 days after seeding and (fresh and dry) biomass production after 40 days. Tree experiments were done: one with recently contaminated light oil, one with recently contaminated heavy oil and one with old contamination. After 5 days from sowing, the largest number of germinated seeds was found in the experiments with old contamination. The fewest germinated seeds was found in the experience with light oil. The experience with heavy oil showed an intermediate number of emerged plants. In all cases fertilization led to a significant increase of the wheat biomass. After 40 days, the level of total hydrocarbons was reduced on average by 55% in the case of contamination with light oil, by 42% for heavy oil contamination and 12% for old contamination. The BTEX concentration in soil had the lowest values in the experiment with heavy oil contamination, intermediate values in the experiment with historic contamination and higher values within experiment with light oil. We make proposal to change intervention thresholds for sensitive land uses from 500 mg/kg for total oil hydrocarbons to 1000 mg/kg for recently pollution and 2000 mg/kg for old pollution (historical > 5 years). For less sensitive land uses intervention thresholds from 2000 mg/kg of total oil hydrocarbons, values increase to 500 mg/kg for recently pollution and 1000 mg/kg old pollution.

  19. 14 CFR 27.339 - Resultant limit maneuvering loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... maximum design rotor tip speed ratio. The rotor tip speed ratio is the ratio of the rotorcraft flight velocity component in the plane of the rotor disc to the rotational tip speed of the rotor blades, and...

  20. 14 CFR 27.339 - Resultant limit maneuvering loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... maximum design rotor tip speed ratio. The rotor tip speed ratio is the ratio of the rotorcraft flight velocity component in the plane of the rotor disc to the rotational tip speed of the rotor blades, and...

  1. 14 CFR 27.339 - Resultant limit maneuvering loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... maximum design rotor tip speed ratio. The rotor tip speed ratio is the ratio of the rotorcraft flight velocity component in the plane of the rotor disc to the rotational tip speed of the rotor blades, and...

  2. 14 CFR 27.339 - Resultant limit maneuvering loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... maximum design rotor tip speed ratio. The rotor tip speed ratio is the ratio of the rotorcraft flight velocity component in the plane of the rotor disc to the rotational tip speed of the rotor blades, and...

  3. KENNEDY SPACE CENTER, FLA. - Japanese astronaut Koichi Wakata gestures as he examines the spar installation (behind him) on the wing of the orbiter Atlantis. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing via the spars - a series of floating joints - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

    NASA Image and Video Library

    2003-09-05

    KENNEDY SPACE CENTER, FLA. - Japanese astronaut Koichi Wakata gestures as he examines the spar installation (behind him) on the wing of the orbiter Atlantis. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing via the spars - a series of floating joints - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

  4. KENNEDY SPACE CENTER, FLA. - Japanese astronaut Koichi Wakata (front) listens to William Gaetjens, with the Vehicle Integration Test Team (VITT), who is providing details about the spar installation (left) on the wing of the orbiter Atlantis. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing via the spars - a series of floating joints - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

    NASA Image and Video Library

    2003-09-05

    KENNEDY SPACE CENTER, FLA. - Japanese astronaut Koichi Wakata (front) listens to William Gaetjens, with the Vehicle Integration Test Team (VITT), who is providing details about the spar installation (left) on the wing of the orbiter Atlantis. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing via the spars - a series of floating joints - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

  5. KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, Mike Hyatt, with United Space Alliance, installs a spar on the wing of the orbiter Atlantis. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing with a series of floating joints - spars - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

    NASA Image and Video Library

    2003-09-04

    KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, Mike Hyatt, with United Space Alliance, installs a spar on the wing of the orbiter Atlantis. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing with a series of floating joints - spars - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

  6. KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, John Newport, with United Space Alliance, inspects the wing of the orbiter Atlantis before installing a spar. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing with a series of floating joints - spars - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

    NASA Image and Video Library

    2003-09-04

    KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, John Newport, with United Space Alliance, inspects the wing of the orbiter Atlantis before installing a spar. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing with a series of floating joints - spars - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

  7. KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, John Newport, with United Space Alliance, inspects spar installation on the wing of the orbiter Atlantis. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing with a series of floating joints - spars - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

    NASA Image and Video Library

    2003-09-04

    KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, John Newport, with United Space Alliance, inspects spar installation on the wing of the orbiter Atlantis. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing with a series of floating joints - spars - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

  8. KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, Mike Hyatt (above) and Saul Ngy (below), with United Space Alliance, install a spar on the wing of the orbiter Atlantis. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing with a series of floating joints - spars - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

    NASA Image and Video Library

    2003-09-04

    KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, Mike Hyatt (above) and Saul Ngy (below), with United Space Alliance, install a spar on the wing of the orbiter Atlantis. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing with a series of floating joints - spars - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

  9. KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, John Newport, with United Space Alliance, inspects a piece of equipment for spar installation on the wing of the orbiter Atlantis. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing with a series of floating joints - spars - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

    NASA Image and Video Library

    2003-09-04

    KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, John Newport, with United Space Alliance, inspects a piece of equipment for spar installation on the wing of the orbiter Atlantis. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing with a series of floating joints - spars - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

  10. KENNEDY SPACE CENTER, FLA. - Japanese astronaut Koichi Wakata (right) listens to William Gaetjens, with the Vehicle Integration Test Team (VITT), who is providing details about the spar installation (left) on the wing of the orbiter Atlantis. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing via the spars - a series of floating joints - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

    NASA Image and Video Library

    2003-09-05

    KENNEDY SPACE CENTER, FLA. - Japanese astronaut Koichi Wakata (right) listens to William Gaetjens, with the Vehicle Integration Test Team (VITT), who is providing details about the spar installation (left) on the wing of the orbiter Atlantis. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing via the spars - a series of floating joints - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

  11. KENNEDY SPACE CENTER, FLA. - Mike Hyatt (left) and Saul Ngy, technicians with United Space Alliance, prepare to install a spar on the wing of the orbiter Atlantis. The Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing with a series of floating joints - spars - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

    NASA Image and Video Library

    2003-08-22

    KENNEDY SPACE CENTER, FLA. - Mike Hyatt (left) and Saul Ngy, technicians with United Space Alliance, prepare to install a spar on the wing of the orbiter Atlantis. The Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing with a series of floating joints - spars - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

  12. KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, John Newport, with United Space Alliance, inspects a spar to be installed on the wing of the orbiter Atlantis. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing with a series of floating joints - spars - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

    NASA Image and Video Library

    2003-09-04

    KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, John Newport, with United Space Alliance, inspects a spar to be installed on the wing of the orbiter Atlantis. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing with a series of floating joints - spars - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

  13. KENNEDY SPACE CENTER, FLA. - William Gaetjens (background), with the Vehicle Integration Test Team (VITT) directs Japanese astronaut Koichi Wakata’s attention to the spars installed on the wing of the orbiter Atlantis. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing via the spars - a series of floating joints - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

    NASA Image and Video Library

    2003-09-05

    KENNEDY SPACE CENTER, FLA. - William Gaetjens (background), with the Vehicle Integration Test Team (VITT) directs Japanese astronaut Koichi Wakata’s attention to the spars installed on the wing of the orbiter Atlantis. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing via the spars - a series of floating joints - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

  14. KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, Mike Hyatt (left) and Saul Ngy (right), with United Space Alliance, finish installing a spar on the wing of the orbiter Atlantis. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing with a series of floating joints - spars - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

    NASA Image and Video Library

    2003-09-04

    KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, Mike Hyatt (left) and Saul Ngy (right), with United Space Alliance, finish installing a spar on the wing of the orbiter Atlantis. Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing with a series of floating joints - spars - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

  15. KENNEDY SPACE CENTER, FLA. - Technician Saul Ngy, with United Space Alliance, prepares to install a spar on the wing of the orbiter Atlantis. The Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing with a series of floating joints - spars - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

    NASA Image and Video Library

    2003-08-22

    KENNEDY SPACE CENTER, FLA. - Technician Saul Ngy, with United Space Alliance, prepares to install a spar on the wing of the orbiter Atlantis. The Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing with a series of floating joints - spars - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

  16. KENNEDY SPACE CENTER, FLA. - Mike Hyatt (left) and Saul Ngy, technicians with United Space Alliance, install a spar on the wing of the orbiter Atlantis. The Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing with a series of floating joints - spars - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

    NASA Image and Video Library

    2003-08-22

    KENNEDY SPACE CENTER, FLA. - Mike Hyatt (left) and Saul Ngy, technicians with United Space Alliance, install a spar on the wing of the orbiter Atlantis. The Reinforced Carbon Carbon (RCC) panels are mechanically attached to the wing with a series of floating joints - spars - to reduce loading on the panels caused by wing deflections. The aluminum and the metallic attachments are protected from exceeding temperature limits by internal insulation.

  17. FUEL CASK IMPACT LIMITER VULNERABILITIES

    SciTech Connect

    Leduc, D; Jeffery England, J; Roy Rothermel, R

    2009-02-09

    Cylindrical fuel casks often have impact limiters surrounding just the ends of the cask shaft in a typical 'dumbbell' arrangement. The primary purpose of these impact limiters is to absorb energy to reduce loads on the cask structure during impacts associated with a severe accident. Impact limiters are also credited in many packages with protecting closure seals and maintaining lower peak temperatures during fire events. For this credit to be taken in safety analyses, the impact limiter attachment system must be shown to retain the impact limiter following Normal Conditions of Transport (NCT) and Hypothetical Accident Conditions (HAC) impacts. Large casks are often certified by analysis only because of the costs associated with testing. Therefore, some cask impact limiter attachment systems have not been tested in real impacts. A recent structural analysis of the T-3 Spent Fuel Containment Cask found problems with the design of the impact limiter attachment system. Assumptions in the original Safety Analysis for Packaging (SARP) concerning the loading in the attachment bolts were found to be inaccurate in certain drop orientations. This paper documents the lessons learned and their applicability to impact limiter attachment system designs.

  18. Load sensing system

    DOEpatents

    Sohns, C.W.; Nodine, R.N.; Wallace, S.A.

    1999-05-04

    A load sensing system inexpensively monitors the weight and temperature of stored nuclear material for long periods of time in widely variable environments. The system can include an electrostatic load cell that encodes weight and temperature into a digital signal which is sent to a remote monitor via a coaxial cable. The same cable is used to supply the load cell with power. When multiple load cells are used, vast inventories of stored nuclear material can be continuously monitored and inventoried of minimal cost. 4 figs.

  19. Dynamic localized load balancing

    NASA Astrophysics Data System (ADS)

    Balandin, Sergey I.; Heiner, Andreas P.

    2003-08-01

    Traditionally dynamic load balancing is applied in resource-reserved connection-oriented networks with a large degree of managed control. Load balancing in connectionless networks is rather rudimentary and is either static or requires network-wide load information. This paper presents a fully automated, traffic driven dynamic load balancing mechanism that uses local load information. The proposed mechanism is easily deployed in a multi-vendor environment in which only a subset of routers supports the function. The Dynamic Localized Load Balancing (DLLB) mechanism distributes traffic based on two sets of weights. The first set is fixed and is inverse proportional to the path cost, typically the sum of reciprocal bandwidths along the path. The second weight reflects the utilization of the link to the first next hop along the path, and is therefore variable. The ratio of static weights defines the ideal load distribution, the ratio of variable weights the node-local load distribution estimate. By minimizing the difference between variable and fixed ratios the traffic distribution, with the available node-local knowledge, is optimal. The above mechanism significantly increases throughput and decreases delay from a network-wide perspective. Optionally the variable weight can include load information of nodes downstream to prevent congestion on those nodes. The latter function further improves network performance, and is easily implemented on top of the standard OSPF signaling. The mechanism does not require many node resources and can be implemented on existing router platforms.

  20. Load regulating expansion fixture

    DOEpatents

    Wagner, L.M.; Strum, M.J.

    1998-12-15

    A free standing self contained device for bonding ultra thin metallic films, such as 0.001 inch beryllium foils is disclosed. The device will regulate to a predetermined load for solid state bonding when heated to a bonding temperature. The device includes a load regulating feature, whereby the expansion stresses generated for bonding are regulated and self adjusting. The load regulator comprises a pair of friction isolators with a plurality of annealed copper members located therebetween. The device, with the load regulator, will adjust to and maintain a stress level needed to successfully and economically complete a leak tight bond without damaging thin foils or other delicate components. 1 fig.

  1. Load regulating expansion fixture

    DOEpatents

    Wagner, Lawrence M.; Strum, Michael J.

    1998-01-01

    A free standing self contained device for bonding ultra thin metallic films, such as 0.001 inch beryllium foils. The device will regulate to a predetermined load for solid state bonding when heated to a bonding temperature. The device includes a load regulating feature, whereby the expansion stresses generated for bonding are regulated and self adjusting. The load regulator comprises a pair of friction isolators with a plurality of annealed copper members located therebetween. The device, with the load regulator, will adjust to and maintain a stress level needed to successfully and economically complete a leak tight bond without damaging thin foils or other delicate components.

  2. A review of research in rotor loads

    NASA Technical Reports Server (NTRS)

    Bousman, William G.; Mantay, Wayne R.

    1988-01-01

    The research accomplished in the area of rotor loads over the last 13 to 14 years is reviewed. The start of the period examined is defined by the 1973 AGARD Milan conference and the 1974 hypothetical rotor comparison. The major emphasis of the review is research performed by the U.S. Army and NASA at their laboratories and/or by the industry under government contract. For the purpose of this review, two main topics are addressed: rotor loads prediction and means of rotor loads reduction. A limited discussion of research in gust loads and maneuver loads is included. In the area of rotor loads predictions, the major problem areas are reviewed including dynamic stall, wake induced flows, blade tip effects, fuselage induced effects, blade structural modeling, hub impedance, and solution methods. It is concluded that the capability to predict rotor loads has not significantly improved in this time frame. Future progress will require more extensive correlation of measurements and predictions to better understand the causes of the problems, and a recognition that differences between theory and measurement have multiple sources, yet must be treated as a whole. There is a need for high-quality data to support future research in rotor loads, but the resulting data base must not be seen as an end in itself. It will be useful only if it is integrated into firm long-range plans for the use of the data.

  3. Electronic Load Bank

    NASA Technical Reports Server (NTRS)

    Huston, Steven W.

    1992-01-01

    Electronic load-bank circuit provides pulsed or continuous low-resistance load to imitate effect of short circuit on Ni/H2 or other electrochemical power cells. Includes safety/warning feature and taps for measurement of cell-output voltage and current.

  4. Microbial load monitor

    NASA Technical Reports Server (NTRS)

    Caplin, R. S.; Royer, E. R.

    1977-01-01

    Design analysis of a microbial load monitor system flight engineering model was presented. Checkout of the card taper and media pump system was fabricated as well as the final two incubating reading heads, the sample receiving and card loading device assembly, related sterility testing, and software. Progress in these areas was summarized.

  5. Strip and load data

    NASA Technical Reports Server (NTRS)

    Jones, R. H.

    1984-01-01

    The method of taking batch data files and loading these files into the ADABAS data base management system (DBMS) is examined. This strip and load process allows the user to quickly become productive. Techniques for data fields and files definition are also included.

  6. CRITICAL LOADS METHODS

    EPA Science Inventory

    I summarize the results of an interagency project that 1) defines a generic approach to quantifying and reporting critical loads, and 2) exercises that generic approach by examining a data rich system -- the critical loads of sulfur deposition and it's effect on the chronic acidi...

  7. Combining ascent loads

    NASA Technical Reports Server (NTRS)

    Houbolt, J. C.

    1972-01-01

    Criteria and guidelines are presented for combining loads that develop during the ascent phase of a space flight. The primary load-caring structure is discussed including the basic tank and interconnecting members, engine support mounts and connections to tank structure, transition structures between stages, payload shrouds, and the basic support points at separation planes.

  8. Load induced blindness.

    PubMed

    Macdonald, James S P; Lavie, Nilli

    2008-10-01

    Although the perceptual load theory of attention has stimulated a great deal of research, evidence for the role of perceptual load in determining perception has typically relied on indirect measures that infer perception from distractor effects on reaction times or neural activity (see N. Lavie, 2005, for a review). Here we varied the level of perceptual load in a letter-search task and assessed its effect on the conscious perception of a search-irrelevant shape stimulus appearing in the periphery, using a direct measure of awareness (present/absent reports). Detection sensitivity (d') was consistently reduced with high, compared to low, perceptual load but was unaffected by the level of working memory load. Because alternative accounts in terms of expectation, memory, response bias, and goal-neglect due to the more strenuous high load task were ruled out, these experiments clearly demonstrate that high perceptual load determines conscious perception, impairing the ability to merely detect the presence of a stimulus--a phenomenon of load induced blindness.

  9. Load Induced Blindness

    ERIC Educational Resources Information Center

    Macdonald, James S. P.; Lavie, Nilli

    2008-01-01

    Although the perceptual load theory of attention has stimulated a great deal of research, evidence for the role of perceptual load in determining perception has typically relied on indirect measures that infer perception from distractor effects on reaction times or neural activity (see N. Lavie, 2005, for a review). Here we varied the level of…

  10. Age Limits.

    PubMed

    Antfolk, Jan

    2017-03-01

    Whereas women of all ages prefer slightly older sexual partners, men-regardless of their age-have a preference for women in their 20s. Earlier research has suggested that this difference between the sexes' age preferences is resolved according to women's preferences. This research has not, however, sufficiently considered that the age range of considered partners might change over the life span. Here we investigated the age limits (youngest and oldest) of considered and actual sex partners in a population-based sample of 2,655 adults (aged 18-50 years). Over the investigated age span, women reported a narrower age range than men and women tended to prefer slightly older men. We also show that men's age range widens as they get older: While they continue to consider sex with young women, men also consider sex with women their own age or older. Contrary to earlier suggestions, men's sexual activity thus reflects also their own age range, although their potential interest in younger women is not likely converted into sexual activity. Compared to homosexual men, bisexual and heterosexual men were more unlikely to convert young preferences into actual behavior, supporting female-choice theory.

  11. Transportation and handling loads

    NASA Technical Reports Server (NTRS)

    Ostrem, F. E.

    1971-01-01

    Criteria and recommended practices are presented for the prediction and verification of transportation and handling loads for the space vehicle structure and for monitoring these loads during transportation and handling of the vehicle or major vehicle segments. Elements of the transportation and handling systems, and the forcing functions and associated loads are described. The forcing functions for common carriers and typical handling devices are assessed, and emphasis is given to the assessment of loads at the points where the space vehicle is supported during transportation and handling. Factors which must be considered when predicting the loads include the transportation and handling medium; type of handling fixture; transport vehicle speed; types of terrain; weather (changes in pressure of temperature, wind, etc.); and dynamics of the transportation modes or handling devices (acceleration, deceleration, and rotations of the transporter or handling device).

  12. Booster Interface Loads

    NASA Technical Reports Server (NTRS)

    Gentz, Steve; Wood, Bill; Nettles, Mindy

    2015-01-01

    The interaction between shock waves and the wake shed from the forward booster/core attach hardware results in unsteady pressure fluctuations, which can lead to large buffeting loads on the vehicle. This task investigates whether computational tools can adequately predict these flows, and whether alternative booster nose shapes can reduce these loads. Results from wind tunnel tests will be used to validate the computations and provide design information for future Space Launch System (SLS) configurations. The current work combines numerical simulations with wind tunnel testing to predict buffeting loads caused by the boosters. Variations in nosecone shape, similar to the Ariane 5 design (fig. 1), are being evaluated with regard to lowering the buffet loads. The task will provide design information for the mitigation of buffet loads for SLS, along with validated simulation tools to be used to assess future SLS designs.

  13. Lightening the Load

    PubMed Central

    Remington, Anna M.; Swettenham, John G.; Lavie, Nilli

    2012-01-01

    Autism spectrum disorder (ASD) research portrays a mixed picture of attentional abilities with demonstrations of enhancements (e.g., superior visual search) and deficits (e.g., higher distractibility). Here we test a potential resolution derived from the Load Theory of Attention (e.g., Lavie, 2005). In Load Theory, distractor processing depends on the perceptual load of the task and as such can only be eliminated under high load that engages full capacity. We hypothesize that ASD involves enhanced perceptual capacity, leading to the superior performance and increased distractor processing previously reported. Using a signal-detection paradigm, we test this directly and demonstrate that, under higher levels of load, perceptual sensitivity was reduced in typical adults but not in adults with ASD. These findings confirm our hypothesis and offer a promising solution to the previous discrepancies by suggesting that increased distractor processing in ASD results not from a filtering deficit but from enhanced perceptual capacity. PMID:22428792

  14. Current limiting remote power control module

    NASA Technical Reports Server (NTRS)

    Hopkins, Douglas C.

    1990-01-01

    The power source for the Space Station Freedom will be fully utilized nearly all of the time. As such, any loads on the system will need to operate within expected limits. Should any load draw an inordinate amount of power, the bus voltage for the system may sag and disrupt the operation of other loads. To protect the bus and loads some type of power interface between the bus and each load must be provided. This interface is most crucial when load faults occur. A possible system configuration is presented. The proposed interface is the Current Limiting Remote Power Controller (CL-RPC). Such an interface should provide the following power functions: limit overloading and resulting undervoltage; prevent catastrophic failure and still provide for redundancy management within the load; minimize cable heating; and provide accurate current measurement. A functional block diagram of the power processing stage of a CL-RPC is included. There are four functions that drive the circuit design: rate control of current; current sensing; the variable conductance switch (VCS) technology; and the algorithm used for current limiting. Each function is discussed separately.

  15. Optimal Control Allocation with Load Sensor Feedback for Active Load Suppression, Experiment Development

    NASA Technical Reports Server (NTRS)

    Miller, Christopher J.; Goodrick, Dan

    2017-01-01

    The problem of control command and maneuver induced structural loads is an important aspect of any control system design. The aircraft structure and the control architecture must be designed to achieve desired piloted control responses while limiting the imparted structural loads. The classical approach is to utilize high structural margins, restrict control surface commands to a limited set of analyzed combinations, and train pilots to follow procedural maneuvering limitations. With recent advances in structural sensing and the continued desire to improve safety and vehicle fuel efficiency, it is both possible and desirable to develop control architectures that enable lighter vehicle weights while maintaining and improving protection against structural damage. An optimal control technique has been explored and shown to achieve desirable vehicle control performance while limiting sensed structural loads. The subject of this paper is the design of the optimal control architecture, and provides the reader with some techniques for tailoring the architecture, along with detailed simulation results.

  16. Load Balancing Scientific Applications

    SciTech Connect

    Pearce, Olga Tkachyshyn

    2014-12-01

    The largest supercomputers have millions of independent processors, and concurrency levels are rapidly increasing. For ideal efficiency, developers of the simulations that run on these machines must ensure that computational work is evenly balanced among processors. Assigning work evenly is challenging because many large modern parallel codes simulate behavior of physical systems that evolve over time, and their workloads change over time. Furthermore, the cost of imbalanced load increases with scale because most large-scale scientific simulations today use a Single Program Multiple Data (SPMD) parallel programming model, and an increasing number of processors will wait for the slowest one at the synchronization points. To address load imbalance, many large-scale parallel applications use dynamic load balance algorithms to redistribute work evenly. The research objective of this dissertation is to develop methods to decide when and how to load balance the application, and to balance it effectively and affordably. We measure and evaluate the computational load of the application, and develop strategies to decide when and how to correct the imbalance. Depending on the simulation, a fast, local load balance algorithm may be suitable, or a more sophisticated and expensive algorithm may be required. We developed a model for comparison of load balance algorithms for a specific state of the simulation that enables the selection of a balancing algorithm that will minimize overall runtime.

  17. Cable load sensing device

    DOEpatents

    Beus, Michael J.; McCoy, William G.

    1998-01-01

    Apparatus for sensing the magnitude of a load on a cable as the cable is employed to support the load includes a beam structure clamped to the cable so that a length of the cable lies along the beam structure. A spacer associated with the beam structure forces a slight curvature in a portion of the length of cable under a cable "no-load" condition so that the portion of the length of cable is spaced from the beam structure to define a cable curved portion. A strain gauge circuit including strain gauges is secured to the beam structure by welding. As the cable is employed to support a load the load causes the cable curved portion to exert a force normal to the cable through the spacer and on the beam structure to deform the beam structure as the cable curved portion attempts to straighten under the load. As this deformation takes place, the resistance of the strain gauges is set to a value proportional to the magnitude of the normal strain on the beam structure during such deformation. The magnitude of the normal strain is manipulated in a control device to generate a value equal to the magnitude or weight of the load supported by the cable.

  18. A loaded thermoacoustic engine

    SciTech Connect

    Olson, J.R.; Swift, G.W.

    1995-11-01

    Measurements and analysis of the performance of a thermoacoustic engine driving a dissipative load are presented. The effect of the load can be explained qualitatively using a simple low-amplitude approximation and quantitatively by invoking a more accurate low-amplitude numerical solution. The heater power {ital @};DQ and hot-end temperature {ital T}{sub {ital H}} are found to be simple functions of the load impedance and the unloaded values of {ital @};DQ and {ital T}{sub {ital H}}. {copyright} {ital 1995} {ital Acoustical} {ital Society} {ital of} {ital America}.

  19. Dynamic load simulator

    NASA Technical Reports Server (NTRS)

    Joncas, K. P.

    1972-01-01

    Concepts and techniques for identifying and simulating both the steady state and dynamic characteristics of electrical loads for use during integrated system test and evaluation are discussed. The investigations showed that it is feasible to design and develop interrogation and simulation equipment to perform the desired functions. During the evaluation, actual spacecraft loads were interrogated by stimulating the loads with their normal input voltage and measuring the resultant voltage and current time histories. Elements of the circuits were optimized by an iterative process of selecting element values and comparing the time-domain response of the model with those obtained from the real equipment during interrogation.

  20. A comprehensive picture of phloem loading strategies

    PubMed Central

    Rennie, Emilie A.; Turgeon, Robert

    2009-01-01

    Mechanisms of phloem loading in the minor veins of leaves are known for only a few species. We propose that there are a limited number of loading strategies for the primary photoassimilates, sucrose and sugar alcohols. These strategies can be predicted based on thermodynamic and anatomical considerations and identified by autoradiography of veins following uptake of 14C-labeled compounds, analysis of leaf solute composition and concentrations, and plasmodesmatal counting. Experiments on 45 dicotyledonous species identified the predicted loading patterns. Over 50-fold differences in concentrations of sucrose and sugar alcohols in leaves were measured. The cumulative concentrations of transport compounds in leaves correlated with loading mechanisms, a previously unrecognized association. Comparisons of solute concentrations and osmotic potentials of whole leaves suggest that sucrose and sugar alcohols are more concentrated in the cytosol than in the vacuoles of mesophyll cells, thus increasing the driving force for passive loading in species that employ this strategy. Passive loading is more widespread than previously thought, especially in trees. The results indicate that plants have exploited all thermodynamically feasible and structurally compatible loading strategies and that these strategies can be identified with straightforward protocols. PMID:19666555

  1. A comprehensive picture of phloem loading strategies.

    PubMed

    Rennie, Emilie A; Turgeon, Robert

    2009-08-18

    Mechanisms of phloem loading in the minor veins of leaves are known for only a few species. We propose that there are a limited number of loading strategies for the primary photoassimilates, sucrose and sugar alcohols. These strategies can be predicted based on thermodynamic and anatomical considerations and identified by autoradiography of veins following uptake of (14)C-labeled compounds, analysis of leaf solute composition and concentrations, and plasmodesmatal counting. Experiments on 45 dicotyledonous species identified the predicted loading patterns. Over 50-fold differences in concentrations of sucrose and sugar alcohols in leaves were measured. The cumulative concentrations of transport compounds in leaves correlated with loading mechanisms, a previously unrecognized association. Comparisons of solute concentrations and osmotic potentials of whole leaves suggest that sucrose and sugar alcohols are more concentrated in the cytosol than in the vacuoles of mesophyll cells, thus increasing the driving force for passive loading in species that employ this strategy. Passive loading is more widespread than previously thought, especially in trees. The results indicate that plants have exploited all thermodynamically feasible and structurally compatible loading strategies and that these strategies can be identified with straightforward protocols.

  2. Final Project Report Load Modeling Transmission Research

    SciTech Connect

    Lesieutre, Bernard; Bravo, Richard; Yinger, Robert; Chassin, Dave; Huang, Henry; Lu, Ning; Hiskens, Ian; Venkataramanan, Giri

    2012-03-31

    The research presented in this report primarily focuses on improving power system load models to better represent their impact on system behavior. The previous standard load model fails to capture the delayed voltage recovery events that are observed in the Southwest and elsewhere. These events are attributed to stalled air conditioner units after a fault. To gain a better understanding of their role in these events and to guide modeling efforts, typical air conditioner units were testing in laboratories. Using data obtained from these extensive tests, new load models were developed to match air conditioner behavior. An air conditioner model is incorporated in the new WECC composite load model. These models are used in dynamic studies of the West and can impact power transfer limits for California. Unit-level and systemlevel solutions are proposed as potential solutions to the delayed voltage recovery problem.

  3. Load research manual. Volume 3. Load research for advanced technologies

    SciTech Connect

    Brandenburg, L.; Clarkson, G.; Grund, Jr., C.; Leo, J.; Asbury, J.; Brandon-Brown, F.; Derderian, H.; Mueller, R.; Swaroop, R.

    1980-11-01

    This three-volume manual presents technical guidelines for electric utility load research. Special attention is given to issues raised by the load data reporting requirements of the Public Utility Regulatory Policies Act of 1978 and to problems faced by smaller utilities that are initiating load research programs. The manual includes guides to load research literature and glossaries of load research and statistical terms. In Volume 3, special load research procedures are presented for solar, wind, and cogeneration technologies.

  4. Statistical load data processing

    NASA Technical Reports Server (NTRS)

    Vandijk, G. M.

    1972-01-01

    A recorder system has been installed on two operational fighter aircrafts. Signal values from a c.g.-acceleration transducer and a strain-gage installation at the wing root were sampled and recorded in digital format on the recorder system. To analyse such load-time histories for fatigue evaluation purposes, a number of counting methods are available in which level crossings, peaks, or ranges are counted. Ten different existing counting principles are defined. The load-time histories are analysed to evaluate these counting methods. For some of the described counting methods, the counting results might be affected by arbitrarily chosen parameters such as the magnitude of load ranges that will be neglected and other secondary counting restrictions. Such influences might invalidate the final counting results entirely. The evaluation shows that for the type of load-time histories associated with most counting methods, a sensible value of the parameters involved can be found.

  5. IT and Building Loads

    SciTech Connect

    Hastbacka, Mildred; Rutberg, Michael; Bouza, Antonio

    2013-09-30

    The article discusses available technologies for reducing IT energy consumption and the commensurate cooling load in commercial buildings. This article addresses the energy savings and market potential of these strategies as well.

  6. Fracture mechanics validity limits

    NASA Technical Reports Server (NTRS)

    Lambert, Dennis M.; Ernst, Hugo A.

    1994-01-01

    Fracture behavior is characteristics of a dramatic loss of strength compared to elastic deformation behavior. Fracture parameters have been developed and exhibit a range within which each is valid for predicting growth. Each is limited by the assumptions made in its development: all are defined within a specific context. For example, the stress intensity parameters, K, and the crack driving force, G, are derived using an assumption of linear elasticity. To use K or G, the zone of plasticity must be small as compared to the physical dimensions of the object being loaded. This insures an elastic response, and in this context, K and G will work well. Rice's J-integral has been used beyond the limits imposed on K and G. J requires an assumption of nonlinear elasticity, which is not characteristic of real material behavior, but is thought to be a reasonable approximation if unloading is kept to a minimum. As well, the constraint cannot change dramatically (typically, the crack extension is limited to ten-percent of the initial remaining ligament length). Rice, et al investigated the properties required of J-type parameters, J(sub x), and showed that the time rate, dJ(sub x)/dt, must not be a function of the crack extension rate, da/dt. Ernst devised the modified-J parameter, J(sub M), that meets this criterion. J(sub M) correlates fracture data to much higher crack growth than does J. Ultimately, a limit of the validity of J(sub M) is anticipated, and this has been estimated to be at a crack extension of about 40-percent of the initial remaining ligament length. None of the various parameters can be expected to describe fracture in an environment of gross plasticity, in which case the process is better described by deformation parameters, e.g., stress and strain. In the current study, various schemes to identify the onset of the plasticity-dominated behavior, i.e., the end of fracture mechanics validity, are presented. Each validity limit parameter is developed in

  7. Lumbriculus variegatus loading study

    EPA Pesticide Factsheets

    Results from sediment bioaccumulation tests with Lumbriculus variegatus with evaluating the effects of organism loading densityThis dataset is associated with the following publication:Burkhard , L., D. Hubin-Barrows, N. Billa, T. Highland , R. Hockett , D. Mount , and T. Norberg-King. Sediment Bioaccumulation Test with Lumbriculus variegatus: Effects of Organism Loading. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY. Springer, New York, NY, USA, 71(7): 70-77, (2016).

  8. LOADING MACHINE FOR REACTORS

    DOEpatents

    Simon, S.L.

    1959-07-01

    An apparatus is described for loading or charging slugs of fissionable material into a nuclear reactor. The apparatus of the invention is a "muzzle loading" type comprising a delivery tube or muzzle designed to be brought into alignment with any one of a plurality of fuel channels. The delivery tube is located within the pressure shell and it is also disposed within shielding barriers while the fuel cantridges or slugs are forced through the delivery tube by an externally driven flexible ram.

  9. Composite Load Model Evaluation

    SciTech Connect

    Lu, Ning; Qiao, Hong

    2007-09-30

    The WECC load modeling task force has dedicated its effort in the past few years to develop a composite load model that can represent behaviors of different end-user components. The modeling structure of the composite load model is recommended by the WECC load modeling task force. GE Energy has implemented this composite load model with a new function CMPLDW in its power system simulation software package, PSLF. For the last several years, Bonneville Power Administration (BPA) has taken the lead and collaborated with GE Energy to develop the new composite load model. Pacific Northwest National Laboratory (PNNL) and BPA joint force and conducted the evaluation of the CMPLDW and test its parameter settings to make sure that: • the model initializes properly, • all the parameter settings are functioning, and • the simulation results are as expected. The PNNL effort focused on testing the CMPLDW in a 4-bus system. An exhaustive testing on each parameter setting has been performed to guarantee each setting works. This report is a summary of the PNNL testing results and conclusions.

  10. 14 CFR 23.1589 - Loading information.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Operating Limitations and Information Airplane Flight Manual and Approved Manual Material § 23.1589 Loading information. The following... easily removed, relocated, or replaced and that is installed when the airplane was weighed under...

  11. 14 CFR 23.1589 - Loading information.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Operating Limitations and Information Airplane Flight Manual and Approved Manual Material § 23.1589 Loading information. The following... easily removed, relocated, or replaced and that is installed when the airplane was weighed under...

  12. 14 CFR 23.1589 - Loading information.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Operating Limitations and Information Airplane Flight Manual and Approved Manual Material § 23.1589 Loading information. The following... easily removed, relocated, or replaced and that is installed when the airplane was weighed under...

  13. An analysis of running skyline load path.

    Treesearch

    Ward W. Carson; Charles N. Mann

    1971-01-01

    This paper is intended for those who wish to prepare an algorithm to determine the load path of a running skyline. The mathematics of a simplified approach to this running skyline design problem are presented. The approach employs assumptions which reduce the complexity of the problem to the point where it can be solved on desk-top computers of limited capacities. The...

  14. Dynamic Loads Affecting Artillery Launcher Crew

    DTIC Science & Technology

    2004-10-01

    limiters) front and rear wheel axles, the cabin, driving block, the launcher (or an open load-carrying body) as well as flexible- suppressing tyre ...Driver’s seat suspension change included the replacement of mechanical suspension with the pneumatic one, which can be characterized by a lower

  15. Approximating Confidence Intervals for Factor Loadings.

    ERIC Educational Resources Information Center

    Lambert, Zarrel V.; And Others

    1991-01-01

    A method is presented that eliminates some interpretational limitations arising from assumptions implicit in the use of arbitrary rules of thumb to interpret exploratory factor analytic results. The bootstrap method is presented as a way of approximating sampling distributions of estimated factor loadings. Simulated datasets illustrate the…

  16. Compressive Failure of Fiber Composites under Multi-Axial Loading

    NASA Technical Reports Server (NTRS)

    Basu, Shiladitya; Waas, Anthony M.; Ambur, Damodar R.

    2006-01-01

    This paper examines the compressive strength of a fiber reinforced lamina under multi-axial stress states. An equilibrium analysis is carried out in which a kinked band of rotated fibers, described by two angles, is sandwiched between two regions in which the fibers are nominally straight. Proportional multi-axial stress states are examined. The analysis includes the possibility of bifurcation from the current equilibrium state. The compressive strength of the lamina is contingent upon either attaining a load maximum in the equilibrium response or satisfaction of a bifurcation condition, whichever occurs first. The results show that for uniaxial loading a non-zero kink band angle beta produces the minimum limit load. For multi-axial loading, different proportional loading paths show regimes of bifurcation dominated and limit load dominated behavior. The present results are able to capture the beneficial effect of transverse compression in raising the composite compressive strength as observed in experiments.

  17. Compressive failure of fiber composites under multi-axial loading

    NASA Astrophysics Data System (ADS)

    Basu, Shiladitya; Waas, Anthony M.; Ambur, Damodar R.

    2006-03-01

    This paper examines the compressive strength of a fiber reinforced lamina under multi-axial stress states. An equilibrium analysis is carried out in which a kinked band of rotated fibers, described by two angles, is sandwiched between two regions in which the fibers are nominally straight. Proportional multi-axial stress states are examined. The analysis includes the possibility of bifurcation from the current equilibrium state. The compressive strength of the lamina is contingent upon either attaining a load maximum in the equilibrium response or satisfaction of a bifurcation condition, whichever occurs first. The results show that for uniaxial loading a non-zero kink band angle β produces the minimum limit load. For multi-axial loading, different proportional loading paths show regimes of bifurcation dominated and limit load dominated behavior. The present results are able to capture the beneficial effect of transverse compression in raising the composite compressive strength as observed in experiments.

  18. Compressive Failure of Fiber Composites under Multi-Axial Loading

    NASA Technical Reports Server (NTRS)

    Basu, Shiladitya; Waas, Anthony M.; Ambur, Damodar R.

    2006-01-01

    This paper examines the compressive strength of a fiber reinforced lamina under multi-axial stress states. An equilibrium analysis is carried out in which a kinked band of rotated fibers, described by two angles, is sandwiched between two regions in which the fibers are nominally straight. Proportional multi-axial stress states are examined. The analysis includes the possibility of bifurcation from the current equilibrium state. The compressive strength of the lamina is contingent upon either attaining a load maximum in the equilibrium response or satisfaction of a bifurcation condition, whichever occurs first. The results show that for uniaxial loading a non-zero kink band angle beta produces the minimum limit load. For multi-axial loading, different proportional loading paths show regimes of bifurcation dominated and limit load dominated behavior. The present results are able to capture the beneficial effect of transverse compression in raising the composite compressive strength as observed in experiments.

  19. FUTURE AQUATIC NUTRIENT LIMITATIONS. (R827785E02)

    EPA Science Inventory

    Nutrient limitation of phytoplankton growth in aquatic systems is moving towards a higher incidence of P and Si limitation as a result of increased nitrogen loading, a N:P fertilizer use of 26:1 (molar basis), population growth, and relatively stable silicate loading. This res...

  20. Modeling and Simulation of a Helicopter Slung Load Stabilization Device

    NASA Technical Reports Server (NTRS)

    Cicolani, Luigi S.; Ehlers, George E.

    2002-01-01

    This paper addresses the problem of simulation and stabilization of the yaw motions of a cargo container slung load. The study configuration is a UH-60 helicopter carrying a 6ft x 6 ft x 8 ft CONEX container. This load is limited to 60 KIAS in operations and flight testing indicates that it starts spinning in hover and that spin rate increases with airspeed. The simulation reproduced the load yaw motions seen in the flight data after augmenting the load model with terms representing unsteady load yaw moment effects acting to reinforce load oscillations, and augmenting the hook model to include yaw resistance at the hook. The use of a vertical fin to stabilize the load is considered. Results indicate that the CONEX airspeed can be extended to 110 kts using a 3x5 ft fin.

  1. Optimal load scheduling in commercial and residential microgrids

    NASA Astrophysics Data System (ADS)

    Ganji Tanha, Mohammad Mahdi

    Residential and commercial electricity customers use more than two third of the total energy consumed in the United States, representing a significant resource of demand response. Price-based demand response, which is in response to changes in electricity prices, represents the adjustments in load through optimal load scheduling (OLS). In this study, an efficient model for OLS is developed for residential and commercial microgrids which include aggregated loads in single-units and communal loads. Single unit loads which include fixed, adjustable and shiftable loads are controllable by the unit occupants. Communal loads which include pool pumps, elevators and central heating/cooling systems are shared among the units. In order to optimally schedule residential and commercial loads, a community-based optimal load scheduling (CBOLS) is proposed in this thesis. The CBOLS schedule considers hourly market prices, occupants' comfort level, and microgrid operation constraints. The CBOLS' objective in residential and commercial microgrids is the constrained minimization of the total cost of supplying the aggregator load, defined as the microgrid load minus the microgrid generation. This problem is represented by a large-scale mixed-integer optimization for supplying single-unit and communal loads. The Lagrangian relaxation methodology is used to relax the linking communal load constraint and decompose the independent single-unit functions into subproblems which can be solved in parallel. The optimal solution is acceptable if the aggregator load limit and the duality gap are within the bounds. If any of the proposed criteria is not satisfied, the Lagrangian multiplier will be updated and a new optimal load schedule will be regenerated until both constraints are satisfied. The proposed method is applied to several case studies and the results are presented for the Galvin Center load on the 16th floor of the IIT Tower in Chicago.

  2. Wind Turbine Control for Load Reduction

    NASA Astrophysics Data System (ADS)

    Bossanyi, E. A.

    2003-07-01

    This article reviews techniques for the control of wind turbines during power production. Pitch control is used primarily to limit power in high winds, but it also has an important effect on structural loads. Particularly as turbines become larger, there is increasing interest in designing controllers to mitigate loads as far as possible. Torque control in variable-speed turbines is used primarily to maximize energy capture below rated wind speed, and to limit the torque above rated, but it can also be used to reduce certain loads. The design of the control algorithms is clearly of prime importance. Additional sensors such as accelerometers and load sensors can also help the controller to achieve its objectives more effectively. By controlling the pitch of each blade independently, it is also possible to achieve important further reductions in loading. It is important to be able to quantify the benefits of any new controller. Although computer simulations are useful, field trials are also vital. The variability of the real wind means that particular care is needed in the design of the trials.

  3. 40 CFR 86.529-98 - Road load force and inertia weight determination.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... these limits shall be tested at an equivalent inertial mass and road load force specified by the Administrator. Figure F98-9 follows: Figure F98-9 Loaded vehicle mass (kg) Equivalent inertial mass (kg)...

  4. 40 CFR 86.529-98 - Road load force and inertia weight determination.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... these limits shall be tested at an equivalent inertial mass and road load force specified by the Administrator. Figure F98-9 follows: Figure F98-9 Loaded vehicle mass (kg) Equivalent inertial mass (kg)...

  5. E-2C Loads Calibration in DFRC Flight Loads Lab

    NASA Technical Reports Server (NTRS)

    Schuster, Lawrence S.

    2008-01-01

    Objectives: a) Safely and efficiently perform structural load tests on NAVAIR E-2C aircraft to calibrate strain gage instrumentation installed by NAVAIR; b) Collect load test data and derive loads equations for use in NAVAIR flight tests; and c) Assist flight test team with use of loads equations measurements at PAX River.

  6. 14 CFR 31.23 - Flight load factor.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Flight load factor. 31.23 Section 31.23 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS Strength Requirements § 31.23 Flight load factor. In determining limit...

  7. 14 CFR 31.23 - Flight load factor.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Flight load factor. 31.23 Section 31.23 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS Strength Requirements § 31.23 Flight load factor. In determining limit...

  8. 14 CFR 31.23 - Flight load factor.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Flight load factor. 31.23 Section 31.23 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS Strength Requirements § 31.23 Flight load factor. In determining limit...

  9. 14 CFR 31.23 - Flight load factor.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Flight load factor. 31.23 Section 31.23 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS Strength Requirements § 31.23 Flight load factor. In determining limit...

  10. 14 CFR 31.23 - Flight load factor.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Flight load factor. 31.23 Section 31.23 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS Strength Requirements § 31.23 Flight load factor. In determining limit...

  11. Microbial load monitor

    NASA Technical Reports Server (NTRS)

    Caplin, R. S.; Royer, E. R.

    1978-01-01

    Attempts are made to provide a total design of a Microbial Load Monitor (MLM) system flight engineering model. Activities include assembly and testing of Sample Receiving and Card Loading Devices (SRCLDs), operator related software, and testing of biological samples in the MLM. Progress was made in assembling SRCLDs with minimal leaks and which operate reliably in the Sample Loading System. Seven operator commands are used to control various aspects of the MLM such as calibrating and reading the incubating reading head, setting the clock and reading time, and status of Card. Testing of the instrument, both in hardware and biologically, was performed. Hardware testing concentrated on SRCLDs. Biological testing covered 66 clinical and seeded samples. Tentative thresholds were set and media performance listed.

  12. Elastomeric load sharing device

    NASA Technical Reports Server (NTRS)

    Isabelle, Charles J. (Inventor); Kish, Jules G. (Inventor); Stone, Robert A. (Inventor)

    1992-01-01

    An elastomeric load sharing device, interposed in combination between a driven gear and a central drive shaft to facilitate balanced torque distribution in split power transmission systems, includes a cylindrical elastomeric bearing and a plurality of elastomeric bearing pads. The elastomeric bearing and bearing pads comprise one or more layers, each layer including an elastomer having a metal backing strip secured thereto. The elastomeric bearing is configured to have a high radial stiffness and a low torsional stiffness and is operative to radially center the driven gear and to minimize torque transfer through the elastomeric bearing. The bearing pads are configured to have a low radial and torsional stiffness and a high axial stiffness and are operative to compressively transmit torque from the driven gear to the drive shaft. The elastomeric load sharing device has spring rates that compensate for mechanical deviations in the gear train assembly to provide balanced torque distribution between complementary load paths of split power transmission systems.

  13. Truck loading rack blending

    SciTech Connect

    Boubenider, E.

    1995-12-01

    Blending, the combining of two or more components to make a single product, has become widely used in most loading rack applications. Blending should not be confused with additive injection, which is the injection of very small doses of enhancers, detergents and dyes into a product stream. Changes in the environmental protection laws in the early 90`s have put increasing demands on marketing terminals with regards to reformulated fuels and environmental protection concerns. As a result of these new mandates, terminals have turned to blending at the loading rack as an economical and convenient means in meeting these new requirements. This paper will discuss some of these mandates and how loading rack blending is used for different applications. Various types of blending will also be discussed along with considerations for each method.

  14. Composite Materials and Meta Materials for a New Approach to ITER ICRH Loads

    NASA Astrophysics Data System (ADS)

    Bottollier-Curtet, H.; Argouarch, A.; Champeaux, S.; Gouard, Ph.; Le Gallou, J.-H.; Primout, M.; Vulliez, K.; Bécoulet, A.; Litaudon, X.; Magne, R.

    2009-11-01

    Preliminary laboratory testing of ICRH antennas is a very useful step before their commissioning. Traditionally, pure water, salt water or baking soda water loads are used. These "water" loads are convenient but strongly limited in terms of performance testing. We have started two feasibility studies for advanced ICRH loads made of ferroelectric ceramics (passive loads) and meta materials (active loads) [1]. Preliminary results are very encouraging.

  15. Composite Materials and Meta Materials for a New Approach to ITER ICRH Loads

    SciTech Connect

    Bottollier-Curtet, H.; Argouarch, A.; Vulliez, K.; Becoulet, A.; Litaudon, X.; Magne, R.; Champeaux, S.; Gouard, Ph.; Primout, M.; Le Gallou, J.-H.

    2009-11-26

    Preliminary laboratory testing of ICRH antennas is a very useful step before their commissioning. Traditionally, pure water, salt water or baking soda water loads are used. These 'water' loads are convenient but strongly limited in terms of performance testing. We have started two feasibility studies for advanced ICRH loads made of ferroelectric ceramics (passive loads) and meta materials (active loads). Preliminary results are very encouraging.

  16. Ocean Tide Loading Computation

    NASA Technical Reports Server (NTRS)

    Agnew, Duncan Carr

    2005-01-01

    September 15,2003 through May 15,2005 This grant funds the maintenance, updating, and distribution of programs for computing ocean tide loading, to enable the corrections for such loading to be more widely applied in space- geodetic and gravity measurements. These programs, developed under funding from the CDP and DOSE programs, incorporate the most recent global tidal models developed from Topex/Poscidon data, and also local tide models for regions around North America; the design of the algorithm and software makes it straightforward to combine local and global models.

  17. Shear wall ultimate drift limits

    SciTech Connect

    Duffey, T.A.; Goldman, A.; Farrar, C.R.

    1994-04-01

    Drift limits for reinforced-concrete shear walls are investigated by reviewing the open literature for appropriate experimental data. Drift values at ultimate are determined for walls with aspect ratios ranging up to a maximum of 3.53 and undergoing different types of lateral loading (cyclic static, monotonic static, and dynamic). Based on the geometry of actual nuclear power plant structures exclusive of containments and concerns regarding their response during seismic (i.e.,cyclic) loading, data are obtained from pertinent references for which the wall aspect ratio is less than or equal to approximately 1, and for which testing is cyclic in nature (typically displacement controlled). In particular, lateral deflections at ultimate load, and at points in the softening region beyond ultimate for which the load has dropped to 90, 80, 70, 60, and 50 percent of its ultimate value, are obtained and converted to drift information. The statistical nature of the data is also investigated. These data are shown to be lognormally distributed, and an analysis of variance is performed. The use of statistics to estimate Probability of Failure for a shear wall structure is illustrated.

  18. Mechanical Predictors of Discomfort during Load Carriage

    PubMed Central

    Wettenschwiler, Patrick D.; Lorenzetti, Silvio; Stämpfli, Rolf; Rossi, René M.; Ferguson, Stephen J.; Annaheim, Simon

    2015-01-01

    Discomfort during load carriage is a major issue for activities using backpacks (e.g. infantry maneuvers, children carrying school supplies, or outdoor sports). It is currently unclear which mechanical parameters are responsible for subjectively perceived discomfort. The aim of this study was to identify objectively measured mechanical predictors of discomfort during load carriage. We compared twelve different configurations of a typical load carriage system, a commercially available backpack with a hip belt. The pressure distribution under the hip belt and the shoulder strap, as well as the tensile force in the strap and the relative motion of the backpack were measured. Multiple linear regression analyses were conducted to investigate possible predictors of discomfort. The results demonstrate that static peak pressure, or alternatively, static strap force is a significant (p<0.001) predictor of discomfort during load carriage in the shoulder and hip region, accounting for 85% or more of the variation in discomfort. As an additional finding, we discovered that the regression coefficients of these predictors are significantly smaller for the hip than for the shoulder region. As static peak pressure is measured directly on the body, it is less dependent on the type of load carriage system than static strap force. Therefore, static peak pressure is well suited as a generally applicable, objective mechanical parameter for the optimization of load carriage system design. Alternatively, when limited to load carriage systems of the type backpack with hip belt, static strap force is the most valuable predictor of discomfort. The regionally differing regression coefficients of both predictors imply that the hip region is significantly more tolerant than the shoulder region. In order to minimize discomfort, users should be encouraged to shift load from the shoulders to the hip region wherever possible, at the same time likely decreasing the risk of low back pain or injury

  19. On the simulation of ballistic shock loads

    NASA Technical Reports Server (NTRS)

    Hollburg, Uwe

    1987-01-01

    Blast or penetrator-impact induced shocks are characterized by high acceleration levels, particularily in the higher frequency range and for a short time duration. These shocks are dangerous for the equipment of ships, combat vehicles, airplanes or spacecraft structures. As ballistic shock loads are insufficiently simulated by laboratory test machines, researchers designed a ballistic shock simulator. The impact induced shocks are simulated by an explosive and the vehicle to be bombarded is replaced by a simplified structure. This structure is suitable to accommodate any equipment which can be tested up to their load limits.

  20. Vibration of fluid loaded conical shells.

    PubMed

    Caresta, Mauro; Kessissoglou, Nicole J

    2008-10-01

    An analytical model is presented to describe the vibration of a truncated conical shell with fluid loading in the low frequency range. The solution for the dynamic response of the shell is presented in the form of a power series. Fluid loading is taken into account by dividing the shell into narrow strips which are considered to be locally cylindrical. Analytical results are presented for different boundary conditions and have been compared with the computational results from a boundary element model. Limitations of the model to the low frequency range are discussed.

  1. Transfer Mechanisms for Heavy Loads

    NASA Technical Reports Server (NTRS)

    Cassisi, V.

    1986-01-01

    Soft hydraulic system gently maneuvers loads. Upper and lower load-transfer mechanisms attach through mounting holes in vertical beam adjustable or gross positioning. Fine positioning of load accomplished by hydraulic cylinders that move trunnion support and trunnion clamp through short distances. Useful in transferring large loads in railroads, agriculture, shipping, manufacturing, and even precision assembly of large items.

  2. Moving Aerospace Structural Design Practice to a Load and Resistance Factor Approach

    NASA Technical Reports Server (NTRS)

    Larsen, Curtis E.; Raju, Ivatury S.

    2016-01-01

    Aerospace structures are traditionally designed using the factor of safety (FOS) approach. The limit load on the structure is determined and the structure is then designed for FOS times the limit load - the ultimate load. Probabilistic approaches utilize distributions for loads and strengths. Failures are predicted to occur in the region of intersection of the two distributions. The load and resistance factor design (LRFD) approach judiciously combines these two approaches by intensive calibration studies on loads and strength to result in structures that are efficient and reliable. This paper discusses these three approaches.

  3. 14 CFR 23.485 - Side load conditions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... positions. (b) The limit vertical load factor must be 1.33, with the vertical ground reaction divided... reaction divided between the main wheels so that— (1) 0.5 (W) is acting inboard on one side; and (2)...

  4. Phloem Loading. A Reevaluation of the Relationship between Plasmodesmatal Frequencies and Loading Strategies1

    PubMed Central

    Turgeon, Robert; Medville, Richard

    2004-01-01

    The incidence of plasmodesmata in the minor vein phloem of leaves varies widely between species. On this basis, two pathways of phloem loading have been proposed: symplastic where frequencies are high, and apoplastic where they are low. However, putative symplastic-loading species fall into at least two categories. In one, the plants translocate raffinose-family oligosaccharides (RFOs). In the other, the primary sugar in the phloem sap is sucrose (Suc). While a thermodynamically feasible mechanism of symplastic loading has been postulated for species that transport RFOs, no such mechanism is known for Suc transporters. We used p-chloromercuribenzenesulfonic acid inhibition of apoplastic loading to distinguish between the two pathways in three species that have abundant minor vein plasmodesmata and are therefore putative symplastic loaders. Clethra barbinervis and Liquidambar styraciflua transport Suc, while Catalpa speciosa transports RFOs. The results indicate that, contrary to the hypothesis that all species with abundant minor vein plasmodesmata load symplastically, C. barbinervis and L. styraciflua load from the apoplast. C. speciosa, being an RFO transporter, loads from the symplast, as expected. Data from these three species, and from the literature, also indicate that plants with abundant plasmodesmata in the minor vein phloem have abundant plasmodesmata between mesophyll cells. Thus, plasmodesmatal frequencies in the minor veins may be a reflection of overall frequencies in the lamina and may have limited relevance to phloem loading. We suggest that symplastic loading is restricted to plants that translocate oligosaccharides larger than Suc, such as RFOs, and that other plants, no matter how many plasmodesmata they have in the minor vein phloem, load via the apoplast. PMID:15516516

  5. LOADING AND UNLOADING DEVICE

    DOEpatents

    Treshow, M.

    1960-08-16

    A device for loading and unloading fuel rods into and from a reactor tank through an access hole includes parallel links carrying a gripper. These links enable the gripper to go through the access hole and then to be moved laterally from the axis of the access hole to the various locations of the fuel rods in the reactor tank.

  6. Fuel Load (FL)

    Treesearch

    Duncan C. Lutes; Robert E. Keane

    2006-01-01

    The Fuel Load method (FL) is used to sample dead and down woody debris, determine depth of the duff/ litter profile, estimate the proportion of litter in the profile, and estimate total vegetative cover and dead vegetative cover. Down woody debris (DWD) is sampled using the planar intercept technique based on the methodology developed by Brown (1974). Pieces of dead...

  7. Multidimensional spectral load balancing

    DOEpatents

    Hendrickson, Bruce A.; Leland, Robert W.

    1996-12-24

    A method of and apparatus for graph partitioning involving the use of a plurality of eigenvectors of the Laplacian matrix of the graph of the problem for which load balancing is desired. The invention is particularly useful for optimizing parallel computer processing of a problem and for minimizing total pathway lengths of integrated circuits in the design stage.

  8. Phosphorous Loading in Lake Champlain

    NASA Astrophysics Data System (ADS)

    Hoffman, H.; Halliday, B.; Lane, T.

    2016-12-01

    Phosphate movement from different sources into Lake Champlain is a problem. Excess phosphate generates algae growth causing eutrophication. This excessive growth known as algae blooms leads to poor water quality (State of Lake Report, 2015). Phosphate moves primarily by attachment to soil particles (Busman, Lamb, 09). Historically its movement has been limited to spring, summer and fall. Spring runoff is thought to contribute the most phosphate to Lake Champlain (Jensen, Tiessen, 11). With changes in global and local temperatures effecting weather patterns and the winter season, does phosphate continue to move into Lake Champlain during the winter months? Water samples from two tributaries to Lake Champlain were collected biweekly year around for the past three years. These samples were then tested for total suspended solids and phosphate levels. The results indicate that phosphate loading occurs throughout the year even during the winter months.

  9. The nature of operating flight loads and their effect on propulsion system structures

    NASA Technical Reports Server (NTRS)

    Dickenson, K. H.; Martin, R. L.

    1981-01-01

    Past diagnostics studies revealed the primary causes of performance deterioration of high by-pass turbofan engines to be flight loads, erosion, and thermal distortion. The various types of airplane loads that are imposed on the engine throughout the lifetime of an airplane are examined. These include flight loads from gusts and maneuvers and ground loads from takeoff, landing, and taxi conditions. Clarification is made in definitions of the airframer's limit and ultimate design loads and the engine manufacturer's operating design loads. Finally, the influence of these loads on the propulsion system structures is discussed.

  10. Load research manual. Volume 1. Load research procedures

    SciTech Connect

    Brandenburg, L.; Clarkson, G.; Grund, Jr., C.; Leo, J.; Asbury, J.; Brandon-Brown, F.; Derderian, H.; Mueller, R.; Swaroop, R.

    1980-11-01

    This three-volume manual presents technical guidelines for electric utility load research. Special attention is given to issues raised by the load data reporting requirements of the Public Utility Regulatory Policies Act of 1978 and to problems faced by smaller utilities that are initiating load research programs. In Volumes 1 and 2, procedures are suggested for determining data requirements for load research, establishing the size and customer composition of a load survey sample, selecting and using equipment to record customer electricity usage, processing data tapes from the recording equipment, and analyzing the data. Statistical techniques used in customer sampling are discussed in detail. The costs of load research also are estimated, and ongoing load research programs at three utilities are described. The manual includes guides to load research literature and glossaries of load research and statistical terms.

  11. Measuring alignment of loading fixture

    DOEpatents

    Scavone, Donald W.

    1989-01-01

    An apparatus and method for measuring the alignment of a clevis and pin type loading fixture for compact tension specimens include a pair of substantially identical flat loading ligaments. Each loading ligament has two apertures for the reception of a respective pin of the loading fixture and a thickness less than one-half of a width of the clevis opening. The pair of loading ligaments are mounted in the clevis openings at respective sides thereof. The loading ligaments are then loaded by the pins of the loading fixture and the strain in each loading ligament is measured. By comparing the relative strain of each loading ligament, the alignment of the loading fixture is determined. Preferably, a suitable strain gage device is located at each longitudinal edge of a respective loading ligament equidistant from the two apertures in order to determine the strain thereat and hence the strain of each ligament. The loading ligaments are made substantially identical by jig grinding the loading ligaments as a matched set. Each loading ligament can also be individually calibrated prior to the measurement.

  12. The reliability of the Extra Load Index as a measure of relative load carriage economy.

    PubMed

    Hudson, Sean; Cooke, Carlton; Lloyd, Ray

    2017-02-01

    The aim of this study was to measure the reliability of the extra load index (ELI) as a method for assessing relative load carriage economy. Seventeen volunteers (12 males, 5 females) performed walking trials at 3 km·h(-1), 6 km·h(-1) and a self-selected speed. Trial conditions were repeated 7 days later to assess test-retest reliability. Trials involved four 4-minute periods of walking, each separated by 5 min of rest. The initial stage was performed unloaded followed in a randomised order by a second unloaded period and walking with backpacks of 7 and 20 kg. Results show ELI values did not differ significantly between trials for any of the speeds (p = 0.46) with either of the additional loads (p = 0.297). The systematic bias, limits of agreement and coefficients of variation were small in all trial conditions. We conclude the ELI appears to be a reliable measure of relative load carriage economy. Practitioner Summary: This paper demonstrates that the ELI is a reliable measure of load carriage economy at a range of walking speeds with both a light and heavy load. The ELI, therefore, represents a useful tool for comparing the relative economy associated with different load carriage systems.

  13. Test load verification through strain data analysis

    NASA Technical Reports Server (NTRS)

    Verderaime, V.; Harrington, F.

    1995-01-01

    A traditional binding acceptance criterion on polycrystalline structures is the experimental verification of the ultimate factor of safety. At fracture, the induced strain is inelastic and about an order-of-magnitude greater than designed for maximum expected operational limit. At this extreme strained condition, the structure may rotate and displace at the applied verification load such as to unknowingly distort the load transfer into the static test article. Test may result in erroneously accepting a submarginal design or rejecting a reliable one. A technique was developed to identify, monitor, and assess the load transmission error through two back-to-back surface-measured strain data. The technique is programmed for expediency and convenience. Though the method was developed to support affordable aerostructures, the method is also applicable for most high-performance air and surface transportation structural systems.

  14. Evolution and manipulation of parasitoid egg load.

    PubMed

    Gandon, Sylvain; Varaldi, Julien; Fleury, Frédéric; Rivero, Ana

    2009-11-01

    In proovigenic parasitoids such as Leptopilina boulardi, the female emerges with a limited egg load and no further eggs are produced during its adult life. A female thus runs the risk of exhausting this limited supply of eggs before the end of her life. Given that the production of an egg is costly, what is the evolutionarily stable egg load at emergence? This question has attracted a lot of attention in the last decade. Here, we analyze a model that allows us to track both the evolution and the population dynamics of a solitary, proovigenic parasitoid. First, we show how host-parasitoid dynamics feedbacks on the evolution of parasitoid egg load. Second, we use this model to consider the situation in which the parasitoid can be infected by a virus that manipulates the oviposition behavior of the females. In particular, we model the effect of the LbFV virus in L. boulardi, a virus that is known to enhance its horizontal transmission by increasing superparasitism (i.e., the laying of eggs in a host already parasitized). Specifically, we model (1) the effect of the virus on parasitoid egg load strategies, and (2) the evolution of egg load manipulation by the virus. This analysis yields two alternative, yet not mutually exclusive, adaptive explanations for the observation that females infected by the virus harbor higher egg loads than uninfected females. Infected females could either respond plastically to the infection status, or be manipulated by the virus. Further experimental work is required to distinguish between these two hypotheses. In a broader context, we present a general theoretical framework that allows us to study the epidemiology, the evolution, the coevolution, and the evolution of manipulation of various reproductive strategies of parasitoids.

  15. Load measurement system with load cell lock-out mechanism

    NASA Technical Reports Server (NTRS)

    Le, Thang; Carroll, Monty; Liu, Jonathan

    1995-01-01

    In the frame work of the project Shuttle Plume Impingement Flight Experiment (SPIFEX), a Load Measurement System was developed and fabricated to measure the impingement force of Shuttle Reaction Control System (RCS) jets. The Load Measurement System is a force sensing system that measures any combination of normal and shear forces up to 40 N (9 lbf) in the normal direction and 22 N (5 lbf) in the shear direction with an accuracy of +/- 0.04 N (+/- 0.01 lbf) Since high resolution is required for the force measurement, the Load Measurement System is built with highly sensitive load cells. To protect these fragile load cells in the non-operational mode from being damaged due to flight loads such as launch and landing loads of the Shuttle vehicle, a motor driven device known as the Load Cell Lock-Out Mechanism was built. This Lock-Out Mechanism isolates the load cells from flight loads and re-engages the load cells for the force measurement experiment once in space. With this highly effective protection system, the SPIFEX load measurement experiment was successfully conducted on STS-44 in September 1994 with all load cells operating properly and reading impingement forces as expected.

  16. Load theory behind the wheel; perceptual and cognitive load effects.

    PubMed

    Murphy, Gillian; Greene, Ciara M

    2017-09-01

    Perceptual Load Theory has been proposed as a resolution to the longstanding early versus late selection debate in cognitive psychology. There is much evidence in support of Load Theory but very few applied studies, despite the potential for the model to shed light on everyday attention and distraction. Using a driving simulator, the effect of perceptual and cognitive load on drivers' visual search was assessed. The findings were largely in line with Load Theory, with reduced distractor processing under high perceptual load, but increased distractor processing under high cognitive load. The effect of load on driving behaviour was also analysed, with significant differences in driving behaviour under perceptual and cognitive load. In addition, the effect of perceptual load on drivers' levels of awareness was investigated. High perceptual load significantly increased inattentional blindness and deafness, for stimuli that were both relevant and irrelevant to driving. High perceptual load also increased RTs to hazards. The current study helps to advance Load Theory by illustrating its usefulness outside of traditional paradigms. There are also applied implications for driver safety and roadway design, as the current study suggests that perceptual and cognitive load are important factors in driver attention. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  17. Fruit load governs transpiration of olive trees

    PubMed Central

    Bustan, Amnon; Dag, Arnon; Yermiyahu, Uri; Erel, Ran; Presnov, Eugene; Agam, Nurit; Kool, Dilia; Iwema, Joost; Zipori, Isaac; Ben-Gal, Alon

    2016-01-01

    We tested the hypothesis that whole-tree water consumption of olives (Olea europaea L.) is fruit load-dependent and investigated the driving physiological mechanisms. Fruit load was manipulated in mature olives grown in weighing-drainage lysimeters. Fruit was thinned or entirely removed from trees at three separate stages of growth: early, mid and late in the season. Tree-scale transpiration, calculated from lysimeter water balance, was found to be a function of fruit load, canopy size and weather conditions. Fruit removal caused an immediate decline in water consumption, measured as whole-plant transpiration normalized to tree size, which persisted until the end of the season. The later the execution of fruit removal, the greater was the response. The amount of water transpired by a fruit-loaded tree was found to be roughly 30% greater than that of an equivalent low- or nonyielding tree. The tree-scale response to fruit was reflected in stem water potential but was not mirrored in leaf-scale physiological measurements of stomatal conductance or photosynthesis. Trees with low or no fruit load had higher vegetative growth rates. However, no significant difference was observed in the overall aboveground dry biomass among groups, when fruit was included. This case, where carbon sources and sinks were both not limiting, suggests that the role of fruit on water consumption involves signaling and alterations in hydraulic properties of vascular tissues and tree organs. PMID:26802540

  18. Fruit load governs transpiration of olive trees.

    PubMed

    Bustan, Amnon; Dag, Arnon; Yermiyahu, Uri; Erel, Ran; Presnov, Eugene; Agam, Nurit; Kool, Dilia; Iwema, Joost; Zipori, Isaac; Ben-Gal, Alon

    2016-03-01

    We tested the hypothesis that whole-tree water consumption of olives (Olea europaea L.) is fruit load-dependent and investigated the driving physiological mechanisms. Fruit load was manipulated in mature olives grown in weighing-drainage lysimeters. Fruit was thinned or entirely removed from trees at three separate stages of growth: early, mid and late in the season. Tree-scale transpiration, calculated from lysimeter water balance, was found to be a function of fruit load, canopy size and weather conditions. Fruit removal caused an immediate decline in water consumption, measured as whole-plant transpiration normalized to tree size, which persisted until the end of the season. The later the execution of fruit removal, the greater was the response. The amount of water transpired by a fruit-loaded tree was found to be roughly 30% greater than that of an equivalent low- or nonyielding tree. The tree-scale response to fruit was reflected in stem water potential but was not mirrored in leaf-scale physiological measurements of stomatal conductance or photosynthesis. Trees with low or no fruit load had higher vegetative growth rates. However, no significant difference was observed in the overall aboveground dry biomass among groups, when fruit was included. This case, where carbon sources and sinks were both not limiting, suggests that the role of fruit on water consumption involves signaling and alterations in hydraulic properties of vascular tissues and tree organs.

  19. Fissile solubility and monosodium titanate loading tests

    SciTech Connect

    Hobbs, D.T.; Fleischman, S.D.

    1993-02-12

    The solubilities of plutonium and uranium have been determined for alkaline salt solutions having compositions which bound those which will be processed in the In-Tank Precipitation (ITP) process. Loadings of plutonium and uranium onto monosodium titanate (MST) have been determined at temperatures bounding those expected to occur during ITP and using a salt solution which was determined to have the maximum solubility for uranium and plutonium. Fissile loadings increase with decreasing amounts of MST in contact with the salt solutions saturated in plutonium and uranium. At MST concentrations bounding those which are planned for the ITP process, expressions for the maximum loadings (wt %) are determined to be 0.29 - 0.20x[MST] for plutonium and 1.8 - 0.29x[MST] for uranium, where [MST] is the concentration of MST in grams/liter. These expressions are valid over the range of MST concentrations from 0.05 to 0.51 g/L and temperatures of 17{degrees}--74{degrees}C. These loadings are below the individual infinitely safe limits for plutonium and uranium. Additional confirmatory experiments are planned to verify the effects of temperature and multiple contacts of the MST with fresh salt solution on the fissile loadings.

  20. Fissile solubility and monosodium titanate loading tests

    SciTech Connect

    Hobbs, D.T.; Fleischman, S.D.

    1993-02-12

    The solubilities of plutonium and uranium have been determined for alkaline salt solutions having compositions which bound those which will be processed in the In-Tank Precipitation (ITP) process. Loadings of plutonium and uranium onto monosodium titanate (MST) have been determined at temperatures bounding those expected to occur during ITP and using a salt solution which was determined to have the maximum solubility for uranium and plutonium. Fissile loadings increase with decreasing amounts of MST in contact with the salt solutions saturated in plutonium and uranium. At MST concentrations bounding those which are planned for the ITP process, expressions for the maximum loadings (wt %) are determined to be 0.29 - 0.20x[MST] for plutonium and 1.8 - 0.29x[MST] for uranium, where [MST] is the concentration of MST in grams/liter. These expressions are valid over the range of MST concentrations from 0.05 to 0.51 g/L and temperatures of 17[degrees]--74[degrees]C. These loadings are below the individual infinitely safe limits for plutonium and uranium. Additional confirmatory experiments are planned to verify the effects of temperature and multiple contacts of the MST with fresh salt solution on the fissile loadings.

  1. Low-Load Space Conditioning Needs Assessment

    SciTech Connect

    Puttagunta, Srikanth

    2015-05-01

    With limited low-load options in the HVAC market, many new-construction housing units are being fitted with oversized equipment - thus facing penalties in system efficiency, comfort, and cost. To bridge the gap between currently available HVAC equipment and the rising demand for low-load HVAC equipment in the marketplace, HVAC equipment manufacturers need to be fully aware of multifamily buildings and single-family homes market needs. Over the past decade, Steven Winter Associates, Inc. (SWA) has provided certification and consulting services on hundreds of housing projects and has accrued a large pool of data. CARB compiled and analyzed these data to see what the thermal load ranges are in various multifamily apartments and attached single-family home types (duplex and townhouse). In total, design loads from 941 dwellings from SWA's recent multifamily and attached single-family work across the Northeast and Mid-Atlantic were analyzed. Information on the dwelling characteristics, design loads, and the specifications of installed mechanical equipment were analyzed to determine any trends that exist within the dataset.

  2. Mechanical stability of trees under dynamic loads.

    PubMed

    James, Kenneth R; Haritos, Nicholas; Ades, Peter K

    2006-10-01

    Tree stability in windstorms and tree failure are important issues in urban areas where there can be risks of damage to people and property and in forests where wind damage causes economic loss. Current methods of managing trees, including pruning and assessment of mechanical strength, are mainly based on visual assessment or the experience of people such as trained arborists. Only limited data are available to assess tree strength and stability in winds, and most recent methods have used a static approach to estimate loads. Recent research on the measurement of dynamic wind loads and the effect on tree stability is giving a better understanding of how different trees cope with winds. Dynamic loads have been measured on trees with different canopy shapes and branch structures including a palm (Washingtonia robusta), a slender Italian cypress (Cupressus sempervirens) and trees with many branches and broad canopies including hoop pine (Araucaria cunninghamii) and two species of eucalypt (Eucalyptus grandis, E. teretecornus). Results indicate that sway is not a harmonic, but is very complex due to the dynamic interaction of branches. A new dynamic model of a tree is described, incorporating the dynamic structural properties of the trunk and branches. The branch mass contributes a dynamic damping, termed mass damping, which acts to reduce dangerous harmonic sway motion of the trunk and so minimizes loads and increases the mechanical stability of the tree. The results from 12 months of monitoring sway motion and wind loading forces are presented and discussed.

  3. Plutonium Immobilization Canister Loading

    SciTech Connect

    Hamilton, E.L.

    1999-01-26

    This disposition of excess plutonium is determined by the Surplus Plutonium Disposition Environmental Impact Statement (SPD-EIS) being prepared by the Department of Energy. The disposition method (Known as ''can in canister'') combines cans of immobilized plutonium-ceramic disks (pucks) with vitrified high-level waste produced at the SRS Defense Waste Processing Facility (DWPF). This is intended to deter proliferation by making the plutonium unattractive for recovery or theft. The envisioned process remotely installs cans containing plutonium-ceramic pucks into storage magazines. Magazines are then remotely loaded into the DWPF canister through the canister neck with a robotic arm and locked into a storage rack inside the canister, which holds seven magazines. Finally, the canister is processed through DWPF and filled with high-level waste glass, thereby surrounding the product cans. This paper covers magazine and rack development and canister loading concepts.

  4. Electrical Load Modeling and Simulation

    SciTech Connect

    Chassin, David P.

    2013-01-01

    Electricity consumer demand response and load control are playing an increasingly important role in the development of a smart grid. Smart grid load management technologies such as Grid FriendlyTM controls and real-time pricing are making their way into the conventional model of grid planning and operations. However, the behavior of load both affects, and is affected by load control strategies that are designed to support electric grid planning and operations. This chapter discussed the natural behavior of electric loads, how it interacts with various load control and demand response strategies, what the consequences are for new grid operation concepts and the computing issues these new technologies raise.

  5. 69. BUILDING NO. 542A, LOADING & UNLOADING DECKS, LOADING AND ...

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

    69. BUILDING NO. 542-A, LOADING & UNLOADING DECKS, LOADING AND UNLOADING RAMP LOOKING NORTHEAST. BUILDING NO. 550, GENERAL STOREHOUSE, IN BACKGROUND LEFT. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

  6. 32. VAL, DETAIL SHOWING LOADING PLATFORM, PROJECTILE LOADING CAR, LAUNCHER ...

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

    32. VAL, DETAIL SHOWING LOADING PLATFORM, PROJECTILE LOADING CAR, LAUNCHER SLAB AND UNDERSIDE OF LAUNCHER BRIDGE LOOKING SOUTHWEST. - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  7. Passive fault current limiting device

    DOEpatents

    Evans, Daniel J.; Cha, Yung S.

    1999-01-01

    A passive current limiting device and isolator is particularly adapted for use at high power levels for limiting excessive currents in a circuit in a fault condition such as an electrical short. The current limiting device comprises a magnetic core wound with two magnetically opposed, parallel connected coils of copper, a high temperature superconductor or other electrically conducting material, and a fault element connected in series with one of the coils. Under normal operating conditions, the magnetic flux density produced by the two coils cancel each other. Under a fault condition, the fault element is triggered to cause an imbalance in the magnetic flux density between the two coils which results in an increase in the impedance in the coils. While the fault element may be a separate current limiter, switch, fuse, bimetal strip or the like, it preferably is a superconductor current limiter conducting one-half of the current load compared to the same limiter wired to carry the total current of the circuit. The major voltage during a fault condition is in the coils wound on the common core in a preferred embodiment.

  8. Passive fault current limiting device

    DOEpatents

    Evans, D.J.; Cha, Y.S.

    1999-04-06

    A passive current limiting device and isolator is particularly adapted for use at high power levels for limiting excessive currents in a circuit in a fault condition such as an electrical short. The current limiting device comprises a magnetic core wound with two magnetically opposed, parallel connected coils of copper, a high temperature superconductor or other electrically conducting material, and a fault element connected in series with one of the coils. Under normal operating conditions, the magnetic flux density produced by the two coils cancel each other. Under a fault condition, the fault element is triggered to cause an imbalance in the magnetic flux density between the two coils which results in an increase in the impedance in the coils. While the fault element may be a separate current limiter, switch, fuse, bimetal strip or the like, it preferably is a superconductor current limiter conducting one-half of the current load compared to the same limiter wired to carry the total current of the circuit. The major voltage during a fault condition is in the coils wound on the common core in a preferred embodiment. 6 figs.

  9. Load responsive hydrodynamic bearing

    DOEpatents

    Kalsi, Manmohan S.; Somogyi, Dezso; Dietle, Lannie L.

    2002-01-01

    A load responsive hydrodynamic bearing is provided in the form of a thrust bearing or journal bearing for supporting, guiding and lubricating a relatively rotatable member to minimize wear thereof responsive to relative rotation under severe load. In the space between spaced relatively rotatable members and in the presence of a liquid or grease lubricant, one or more continuous ring shaped integral generally circular bearing bodies each define at least one dynamic surface and a plurality of support regions. Each of the support regions defines a static surface which is oriented in generally opposed relation with the dynamic surface for contact with one of the relatively rotatable members. A plurality of flexing regions are defined by the generally circular body of the bearing and are integral with and located between adjacent support regions. Each of the flexing regions has a first beam-like element being connected by an integral flexible hinge with one of the support regions and a second beam-like element having an integral flexible hinge connection with an adjacent support region. A least one local weakening geometry of the flexing region is located intermediate the first and second beam-like elements. In response to application of load from one of the relatively rotatable elements to the bearing, the beam-like elements and the local weakening geometry become flexed, causing the dynamic surface to deform and establish a hydrodynamic geometry for wedging lubricant into the dynamic interface.

  10. Buffet Load Alleviation

    NASA Technical Reports Server (NTRS)

    Ryall, T. G.; Moses, R. W.; Hopkins, M. A.; Henderson, D.; Zimcik, D. G.; Nitzsche, F.

    2004-01-01

    High performance aircraft are, by their very nature, often required to undergo maneuvers involving high angles of attack. Under these conditions unsteady vortices emanating from the wing and the fuselage will impinge on the twin fins (required for directional stability) causing excessive buffet loads, in some circumstances, to be applied to the aircraft. These loads result in oscillatory stresses, which may cause significant amounts of fatigue damage. Active control is a possible solution to this important problem. A full-scale test was carried out on an F/A-18 fuselage and fins using piezoceramic actuators to control the vibrations. Buffet loads were simulated using very powerful electromagnetic shakers. The first phase of this test was concerned with the open loop system identification whereas the second stage involved implementing linear time invariant control laws. This paper looks at some of the problems encountered as well as the corresponding solutions and some results. It is expected that flight trials of a similar control system to alleviate buffet will occur as early as 2001.

  11. Shot loading trainer analysis

    SciTech Connect

    Peterson, T.K.

    1995-02-15

    This document presents the results from the analysis of the shot loading trainer (SLT). This device will be used to test the procedure for installing shot into the annulus of the Project W-320 shipping container. To ensure that the shot is installed uniformly around the container, vibrators will be used to settle the shot. The SLT was analyzed to ensure that it would not jeopardize worker safety during operation. The results from the static analysis of the SLT under deadweight and vibrator operating loads show that the stresses in the SLT are below code allowables. The results from the modal analysis show that the natural frequencies of the SLT are far below the operating frequencies of the vibrators, provided the SLT is mounted on pneumatic tires. The SLT was also analyzed for wind, seismic, deadweight, and moving/transporting loads. Analysis of the SLT is in accordance with SDC-4.1 for safety class 3 structures (DOE-RL 1993) and the American Institute of Steel Construction (AISC) Manual of Steel Construction (AISC 1989).

  12. 14 CFR 25.363 - Side load on engine and auxiliary power unit mounts.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... mount and its supporting structure must be designed for a limit load factor in lateral direction, for... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Supplementary...

  13. 14 CFR 25.363 - Side load on engine and auxiliary power unit mounts.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... mount and its supporting structure must be designed for a limit load factor in lateral direction, for... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Supplementary...

  14. 14 CFR 25.363 - Side load on engine and auxiliary power unit mounts.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... mount and its supporting structure must be designed for a limit load factor in lateral direction, for... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Supplementary...

  15. 14 CFR 25.363 - Side load on engine and auxiliary power unit mounts.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... mount and its supporting structure must be designed for a limit load factor in lateral direction, for... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Supplementary...

  16. 14 CFR 25.363 - Side load on engine and auxiliary power unit mounts.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... mount and its supporting structure must be designed for a limit load factor in lateral direction, for... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Supplementary...

  17. Modeling Aircraft Wing Loads from Flight Data Using Neural Networks

    NASA Technical Reports Server (NTRS)

    Allen, Michael J.; Dibley, Ryan P.

    2003-01-01

    Neural networks were used to model wing bending-moment loads, torsion loads, and control surface hinge-moments of the Active Aeroelastic Wing (AAW) aircraft. Accurate loads models are required for the development of control laws designed to increase roll performance through wing twist while not exceeding load limits. Inputs to the model include aircraft rates, accelerations, and control surface positions. Neural networks were chosen to model aircraft loads because they can account for uncharacterized nonlinear effects while retaining the capability to generalize. The accuracy of the neural network models was improved by first developing linear loads models to use as starting points for network training. Neural networks were then trained with flight data for rolls, loaded reversals, wind-up-turns, and individual control surface doublets for load excitation. Generalization was improved by using gain weighting and early stopping. Results are presented for neural network loads models of four wing loads and four control surface hinge moments at Mach 0.90 and an altitude of 15,000 ft. An average model prediction error reduction of 18.6 percent was calculated for the neural network models when compared to the linear models. This paper documents the input data conditioning, input parameter selection, structure, training, and validation of the neural network models.

  18. Static and transient beam loading of a synchrotron

    SciTech Connect

    Zhang, S.Y.; Weng, W.T.

    1992-07-13

    In a synchrotron, when the beam induced current is comparable to the driver current, the RF cavity is subjected to beam loading perturbation and corrective steps have to be implemented to regain beam stability. In this paper, the static and transient beam loading will be studied. We first discuss the static beam loading, which includes the cavity detuning condition, the stability condition, and the generator power dissipation. The beam current induced beam phase deviation is used as criterion to study the transient beam loading. The upgraded and the old AGS RF system parameters are used as an example to demonstrate how to choose cavity and generator parameters to satisfy the stability requirements under the beam loading. The dynamic models for the beam loading with beam control, and the beam loading with fast power amplifier feedback are presented and analyzed. It is shown that the beam phase and radial feedbacks alone are insufficient for the transient beam loading compensation, but the fast power amplifier feedback can provide effective correction on the beam loading. The limitation of the fast feedback and the beam loading with tuning and AVC loops are also discussed.

  19. Static and transient beam loading of a synchrotron

    SciTech Connect

    Zhang, S.Y.; Weng, W.T.

    1992-07-13

    In a synchrotron, when the beam induced current is comparable to the driver current, the RF cavity is subjected to beam loading perturbation and corrective steps have to be implemented to regain beam stability. In this paper, the static and transient beam loading will be studied. We first discuss the static beam loading, which includes the cavity detuning condition, the stability condition, and the generator power dissipation. The beam current induced beam phase deviation is used as criterion to study the transient beam loading. The upgraded and the old AGS RF system parameters are used as an example to demonstrate how to choose cavity and generator parameters to satisfy the stability requirements under the beam loading. The dynamic models for the beam loading with beam control, and the beam loading with fast power amplifier feedback are presented and analyzed. It is shown that the beam phase and radial feedbacks alone are insufficient for the transient beam loading compensation, but the fast power amplifier feedback can provide effective correction on the beam loading. The limitation of the fast feedback and the beam loading with tuning and AVC loops are also discussed.

  20. Immediate loading of mandibular dental implants in partially edentulous patients: a prospective randomized comparative study.

    PubMed

    Margossian, Patrice; Mariani, Paul; Stephan, Grégory; Margerit, Jacques; Jorgensen, Christian

    2012-04-01

    While immediate loading in the edentulous mandible is a well-documented procedure, there are limited scientific data on immediate loading in the partially edentulous mandible. Two-year success rates of immediate loading and conventional delayed loading of dental implants in partially dentate mandibles were compared. Patients were randomized into three groups: group A (n = 40), immediate provisionalization with nonocclusal loading; group B (n = 40), immediate provisionalization with occlusal loading; and group C (n = 37), delayed loading with single-stage surgery. Baseline and 2-year measurements included implant stability quotient, insertion torque, and peri-implant bone crest radiography. Two hundred nine implants were immediately loaded in 80 patients. The 2-year success rates were 93.3% for group B and 100% for groups A and C. Immediate provisionalization provided success rates similar to those for delayed loading only when not loaded in occlusion.

  1. The Critical Compression Load for a Universal Testing Machine When the Specimen Is Loaded Through Knife Edges

    NASA Technical Reports Server (NTRS)

    Lundquist, Eugene E; Schwartz, Edward B

    1942-01-01

    The results of a theoretical and experimental investigation to determine the critical compression load for a universal testing machine are presented for specimens loaded through knife edges. The critical load for the testing machine is the load at which one of the loading heads becomes laterally instable in relation to the other. For very short specimens the critical load was found to be less than the rated capacity given by the manufacturer for the machine. A load-length diagram is proposed for defining the safe limits of the test region for the machine. Although this report is particularly concerned with a universal testing machine of a certain type, the basic theory which led to the derivation of the general equation for the critical load, P (sub cr) = alpha L can be applied to any testing machine operated in compression where the specimen is loaded through knife edges. In this equation, L is the length of the specimen between knife edges and alpha is the force necessary to displace the upper end of the specimen unit horizontal distance relative to the lower end of the specimen in a direction normal to the knife edges through which the specimen is loaded.

  2. Moderate Load Eccentric Exercise; A Distinct Novel Training Modality

    PubMed Central

    Hoppeler, Hans

    2016-01-01

    Over the last 20 years a number of studies have been published using progressive eccentric exercise protocols on motorized ergometers or similar devices that allow for controlled application of eccentric loads. Exercise protocols ramp eccentric loads over an initial 3 weeks period in order to prevent muscle damage and delayed onset muscle soreness. Final training loads reach 400–500 W in rehabilitative settings and over 1200 W in elite athletes. Training is typically carried out three times per week for durations of 20–30 min. This type of training has been characterizes as moderate load eccentric exercise. It has also been denoted RENEW (Resistance Exercise via Negative Eccentric Work by LaStayo et al., 2014). It is distinct from plyometric exercises (i.e., drop jumps) that impose muscle loads of several thousand Watts on muscles and tendons. It is also distinct from eccentric overload training whereby loads in a conventional strength training setting are increased in the eccentric phase of the movement to match concentric loads. Moderate load eccentric exercise (or RENEW) has been shown to be similarly effective as conventional strength training in increasing muscle strength and muscle volume. However, as carried out at higher angular velocities of joint movement, it reduces joint loads. A hallmark of moderate load eccentric exercise is the fact that the energy requirements are typically 4-fold smaller than in concentric exercise of the same load. This makes moderate load eccentric exercise training the tool of choice in medical conditions with limitations in muscle energy supply. The use and effectiveness of moderate load eccentric exercise has been demonstrated mostly in small scale studies for cardiorespiratory conditions, sarcopenia of old age, cancer, diabetes type 2, and neurological conditions. It has also been used effectively in the prevention and rehabilitation of injuries of the locomotor system in particular the rehabilitation after anterior

  3. Moderate Load Eccentric Exercise; A Distinct Novel Training Modality.

    PubMed

    Hoppeler, Hans

    2016-01-01

    Over the last 20 years a number of studies have been published using progressive eccentric exercise protocols on motorized ergometers or similar devices that allow for controlled application of eccentric loads. Exercise protocols ramp eccentric loads over an initial 3 weeks period in order to prevent muscle damage and delayed onset muscle soreness. Final training loads reach 400-500 W in rehabilitative settings and over 1200 W in elite athletes. Training is typically carried out three times per week for durations of 20-30 min. This type of training has been characterizes as moderate load eccentric exercise. It has also been denoted RENEW (Resistance Exercise via Negative Eccentric Work by LaStayo et al., 2014). It is distinct from plyometric exercises (i.e., drop jumps) that impose muscle loads of several thousand Watts on muscles and tendons. It is also distinct from eccentric overload training whereby loads in a conventional strength training setting are increased in the eccentric phase of the movement to match concentric loads. Moderate load eccentric exercise (or RENEW) has been shown to be similarly effective as conventional strength training in increasing muscle strength and muscle volume. However, as carried out at higher angular velocities of joint movement, it reduces joint loads. A hallmark of moderate load eccentric exercise is the fact that the energy requirements are typically 4-fold smaller than in concentric exercise of the same load. This makes moderate load eccentric exercise training the tool of choice in medical conditions with limitations in muscle energy supply. The use and effectiveness of moderate load eccentric exercise has been demonstrated mostly in small scale studies for cardiorespiratory conditions, sarcopenia of old age, cancer, diabetes type 2, and neurological conditions. It has also been used effectively in the prevention and rehabilitation of injuries of the locomotor system in particular the rehabilitation after anterior cruciate

  4. Decreasing Cognitive Load for Learners: Strategy of Web-Based Foreign Language Learning

    ERIC Educational Resources Information Center

    Zhang, Jianfeng

    2013-01-01

    Cognitive load is one of the important factors that influence the effectiveness and efficiency of web-based foreign language learning. Cognitive load theory assumes that human's cognitive capacity in working memory is limited and if it overloads, learning will be hampered, so that high level of cognitive load can affect the performance of learning…

  5. LabVIEW Serial Driver Software for an Electronic Load

    NASA Technical Reports Server (NTRS)

    Scullin, Vincent; Garcia, Christopher

    2003-01-01

    A LabVIEW-language computer program enables monitoring and control of a Transistor Devices, Inc., Dynaload WCL232 (or equivalent) electronic load via an RS-232 serial communication link between the electronic load and a remote personal computer. (The electronic load can operate at constant voltage, current, power consumption, or resistance.) The program generates a graphical user interface (GUI) at the computer that looks and acts like the front panel of the electronic load. Once the electronic load has been placed in remote-control mode, this program first queries the electronic load for the present values of all its operational and limit settings, and then drops into a cycle in which it reports the instantaneous voltage, current, and power values in displays that resemble those on the electronic load while monitoring the GUI images of pushbuttons for control actions by the user. By means of the pushbutton images and associated prompts, the user can perform such operations as changing limit values, the operating mode, or the set point. The benefit of this software is that it relieves the user of the need to learn one method for operating the electronic load locally and another method for operating it remotely via a personal computer.

  6. Multidimensional spectral load balancing

    SciTech Connect

    Hendrickson, B.; Leland, R.

    1993-01-01

    We describe an algorithm for the static load balancing of scientific computations that generalizes and improves upon spectral bisection. Through a novel use of multiple eigenvectors, our new spectral algorithm can divide a computation into 4 or 8 pieces at once. These multidimensional spectral partitioning algorithms generate balanced partitions that have lower communication overhead and are less expensive to compute than those produced by spectral bisection. In addition, they automatically work to minimize message contention on a hypercube or mesh architecture. These spectral partitions are further improved by a multidimensional generalization of the Kernighan-Lin graph partitioning algorithm. Results on several computational grids are given and compared with other popular methods.

  7. Microbial Load Monitor

    NASA Technical Reports Server (NTRS)

    Gibson, S. F.; Royer, E. R.

    1979-01-01

    The Microbial Load Monitor (MLM) is an automated and computerized system for detection and identification of microorganisms. Additionally, the system is designed to enumerate and provide antimicrobic susceptibility profiles for medically significant bacteria. The system is designed to accomplish these tasks in a time of 13 hours or less versus the traditional time of 24 hours for negatives and 72 hours or more for positives usually required for standard microbiological analysis. The MLM concept differs from other methods of microbial detection in that the system is designed to accept raw untreated clinical samples and to selectively identify each group or species that may be present in a polymicrobic sample.

  8. Variable loading roller

    DOEpatents

    Williams, D.M.

    1988-01-21

    An automatic loading roller for transmitting torque in traction drive devices in manipulator arm joints includes a two-part camming device having a first cam portion rotatable in place on a shaft by an input torque and a second cam portion coaxially rotatable and translatable having a rotating drive surface thereon for engaging the driven surface of an output roller with a resultant force proportional to the torque transmitted. Complementary helical grooves in the respective cam portions interconnected through ball bearings interacting with those grooves effect the rotation and translation of the second cam portion in response to rotation of the first. 14 figs.

  9. Variable loading roller

    DOEpatents

    Williams, Daniel M.

    1989-01-01

    An automatic loading roller for transmitting torque in traction drive devices in manipulator arm joints includes a two-part camming device having a first cam portion rotatable in place on a shaft by an input torque and a second cam portion coaxially rotatable and translatable having a rotating drive surface thereon for engaging the driven surface of an output roller with a resultant force proportional to the torque transmitted. Complementary helical grooves on the respective cam portions interconnected through ball bearings interacting with those grooves effect the rotation and translation of the second cam portion in response to rotation of the first.

  10. Plug Loads Conservation Measures

    SciTech Connect

    Ian Metzger, Jesse Dean

    2010-12-31

    This software requires inputs of simple plug loads inventory information and calculates the energy and cost benefits of various retrofit opportunities. This tool includes energy conservation measures for: Vending Machine Misers, Delamp Vending Machine, Desktop to Laptop retrofit, CRT to LCD monitors retrofit, Computer Power Management Settings, and Energy Star Refrigerator retrofit. This tool calculates energy savings, demand reduction, cost savings, building life cycle costs including: simple payback, discounted payback, net-present value, and savings to investment ratio. In addition this tool also displays the environmental benefits of a project.

  11. Schoolbag Weight Limit: Can It Be Defined?

    ERIC Educational Resources Information Center

    Dockrell, Sara; Simms, Ciaran; Blake, Catherine

    2013-01-01

    Background: Carrying a schoolbag is a daily activity for most children and much research has been conducted in an effort to identify a safe load limit for children to carry in their schoolbags. Despite this, there is still no consensus about guideline weight and other factors associated with carrying a schoolbag. The objective of this article is…

  12. Design of the TPX outboard toroidal limiters

    SciTech Connect

    Schaubel, K.M.; Anderson, P.M.; Baxi, C.B.

    1995-12-31

    The Tokamak Physics Experiment outboard limiter system incorporates the passive stabilizer plates, the ripple armor, the toroidal break and the support structures. These components are designed to withstand substantial steady state heat loads and high mechanical forces caused by plasma disruptions. The design of these components has been developed to deal with the challenging thermal, structural and remote handling requirements.

  13. Schoolbag Weight Limit: Can It Be Defined?

    ERIC Educational Resources Information Center

    Dockrell, Sara; Simms, Ciaran; Blake, Catherine

    2013-01-01

    Background: Carrying a schoolbag is a daily activity for most children and much research has been conducted in an effort to identify a safe load limit for children to carry in their schoolbags. Despite this, there is still no consensus about guideline weight and other factors associated with carrying a schoolbag. The objective of this article is…

  14. Electropneumatic transducer automatically limits motor current

    NASA Technical Reports Server (NTRS)

    Lovitt, T. F.

    1966-01-01

    Pneumatic controller regulates the load on a centrifugal freon compressor in a water cooling system, thus limiting the current input to an electric motor driving it. An electromechanical transducer monitoring the motor input current sends out air signals which indicate changes in the current to the pneumatic controller.

  15. Processing capacity under perceptual and cognitive load: a closer look at load theory.

    PubMed

    Fitousi, Daniel; Wenger, Michael J

    2011-06-01

    Variations in perceptual and cognitive demands (load) play a major role in determining the efficiency of selective attention. According to load theory (Lavie, Hirst, Fockert, & Viding, 2004) these factors (a) improve or hamper selectivity by altering the way resources (e.g., processing capacity) are allocated, and (b) tap resources rather than data limitations (Norman & Bobrow, 1975). Here we provide an extensive and rigorous set of tests of these assumptions. Predictions regarding changes in processing capacity are tested using the hazard function of the response time (RT) distribution (Townsend & Ashby, 1978; Wenger & Gibson, 2004). The assumption that load taps resource rather than data limitations is examined using measures of sensitivity and bias drawn from signal detection theory (Swets, 1964). All analyses were performed at two levels: the individual and the aggregate. Hypotheses regarding changes in processing capacity were confirmed at the level of the aggregate. Hypotheses regarding resource and data limitations were not completely supported at either level of analysis. And in all of the analyses, we observed substantial individual differences. In sum, the results suggest a need to expand the theoretical vocabulary of load theory, rather than a need to discard it.

  16. Foot Loading Characteristics of Different Graduations of Partial Weight Bearing

    ERIC Educational Resources Information Center

    Gusinde, Johannes; Pauser, Johannes; Swoboda, Bernd; Gelse, Kolja; Carl, Hans-Dieter

    2011-01-01

    Limited weight bearing of the lower extremity is a commonly applied procedure in orthopaedic rehabilitation after reconstructive forefoot surgery, trauma surgery and joint replacement. The most frequent limitations are given as percentage of body weight (BW) and represent 10 or 50% BW. The extent of foot loading under these graduations of partial…

  17. 14 CFR 23.473 - Ground load conditions and assumptions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... descent velocity) allowed under paragraphs (b) and (c) of this section. (b) The design landing weight may... velocity (V), in feet per second, equal to 4.4 (W/S)1/4, except that this velocity need not be more than 10... are made to determine the limit load factor corresponding to the required limit descent...

  18. Foot Loading Characteristics of Different Graduations of Partial Weight Bearing

    ERIC Educational Resources Information Center

    Gusinde, Johannes; Pauser, Johannes; Swoboda, Bernd; Gelse, Kolja; Carl, Hans-Dieter

    2011-01-01

    Limited weight bearing of the lower extremity is a commonly applied procedure in orthopaedic rehabilitation after reconstructive forefoot surgery, trauma surgery and joint replacement. The most frequent limitations are given as percentage of body weight (BW) and represent 10 or 50% BW. The extent of foot loading under these graduations of partial…

  19. Load Control System Reliability

    SciTech Connect

    Trudnowski, Daniel

    2015-04-03

    This report summarizes the results of the Load Control System Reliability project (DOE Award DE-FC26-06NT42750). The original grant was awarded to Montana Tech April 2006. Follow-on DOE awards and expansions to the project scope occurred August 2007, January 2009, April 2011, and April 2013. In addition to the DOE monies, the project also consisted of matching funds from the states of Montana and Wyoming. Project participants included Montana Tech; the University of Wyoming; Montana State University; NorthWestern Energy, Inc., and MSE. Research focused on two areas: real-time power-system load control methodologies; and, power-system measurement-based stability-assessment operation and control tools. The majority of effort was focused on area 2. Results from the research includes: development of fundamental power-system dynamic concepts, control schemes, and signal-processing algorithms; many papers (including two prize papers) in leading journals and conferences and leadership of IEEE activities; one patent; participation in major actual-system testing in the western North American power system; prototype power-system operation and control software installed and tested at three major North American control centers; and, the incubation of a new commercial-grade operation and control software tool. Work under this grant certainly supported the DOE-OE goals in the area of “Real Time Grid Reliability Management.”

  20. Towards establishing practical multi-hazard bridge design limit states

    NASA Astrophysics Data System (ADS)

    Liang, Zach; Lee, George C.

    2013-09-01

    In the U.S., the current Load and Resistance Factor Design (LRFD) Specifications for highway bridges is a reliability-based formulation that considers failure probabilities of bridge components due to the actions of typical dead load and frequent vehicular loads. Various extreme load effects, such as earthquake and vessel collision, are not considered on the same reliability-based platform. Since these extreme loads are time variables, combining them with frequent, nonextreme loads is a significant challenge. The number of design limit state equations based on these failure probabilities can be unrealistically large and unnecessary from the view point of practical applications. Based on the opinion of AASHTO State Bridge Engineers, many load combinations are insignificant in their states. This paper describes the formulation of a criterion to include only the necessary load combinations to establish the design limit states. This criterion is established by examining the total failure probabilities for all possible time-invariant and time varying load combinations and breaking them down into partial terms. Then, important load combinations can be readily determined quantitatively.

  1. Identification of alternating renewal electric load models from energy measurements

    NASA Astrophysics Data System (ADS)

    El-Ferik, Sami; Malhame, Roland P.

    1994-06-01

    In statistical load modeling methodologies, aggregate electric load behavior is derived by propagating the ensemble statistics of an individual load process which is representative of the loads in the aggregate. Such a modeling philosophy tends to yield models whereby if physical meaning is present at the elemental level, it is preserved at the aggregate level. This property is essential for applications involving direct control of power system loads (for peak load shaving purposes, for example). The potential applicability of statistical load models is a strong function of one's ability to limit the volume of unusual data required to build those. An identification algorithm for a previously proposed stochastic hybrid-state Markov model of individual heating-cooling loads is presented. It relies only on data routinely gathered in power systems (device energy consumption over constant time intervals). It exploits an alternating renewal viewpoint of the load dynamics. After deriving some general results on the occupation statistics of time homogeneous alternating renewal processes, the analysis is focused on the specific model. In the process, however, some intriguing features likely to be shared by a wide class of alternating renewal processes are revealed.

  2. Gender-Specific Effects of Cognitive Load on Social Discounting

    PubMed Central

    Strombach, Tina; Margittai, Zsofia; Gorczyca, Barbara; Kalenscher, Tobias

    2016-01-01

    We live busy, social lives, and meeting the challenges of our complex environments puts strain on our cognitive systems. However, cognitive resources are limited. It is unclear how cognitive load affects social decision making. Previous findings on the effects of cognitive load on other-regarding preferences have been ambiguous, allowing no coherent opinion whether cognitive load increases, decreases or does not affect prosocial considerations. Here, we suggest that social distance between individuals modulates whether generosity towards a recipient increases or decreases under cognitive load conditions. Participants played a financial social discounting task with several recipients at variable social distance levels. In this task, they could choose between generous alternatives, yielding medium financial rewards for the participant and recipient at variable social distances, or between a selfish alternative, yielding larger rewards for the participant alone. We show that the social discount function of male participants was significantly flattened under high cognitive load conditions, suggesting they distinguished less between socially close and socially distant recipients. Unexpectedly, the cognitive-load effect on social discounting was gender-specific: while social discounting was strongly dependent on cognitive load in men, women were nearly unaffected by cognitive load manipulations. We suggest that cognitive load leads men, but not women to simplify the decision problem by neglecting the social distance information. We consider our study a good starting point for further experiments exploring the role of gender in prosocial choice. PMID:27788192

  3. Gender-Specific Effects of Cognitive Load on Social Discounting.

    PubMed

    Strombach, Tina; Margittai, Zsofia; Gorczyca, Barbara; Kalenscher, Tobias

    2016-01-01

    We live busy, social lives, and meeting the challenges of our complex environments puts strain on our cognitive systems. However, cognitive resources are limited. It is unclear how cognitive load affects social decision making. Previous findings on the effects of cognitive load on other-regarding preferences have been ambiguous, allowing no coherent opinion whether cognitive load increases, decreases or does not affect prosocial considerations. Here, we suggest that social distance between individuals modulates whether generosity towards a recipient increases or decreases under cognitive load conditions. Participants played a financial social discounting task with several recipients at variable social distance levels. In this task, they could choose between generous alternatives, yielding medium financial rewards for the participant and recipient at variable social distances, or between a selfish alternative, yielding larger rewards for the participant alone. We show that the social discount function of male participants was significantly flattened under high cognitive load conditions, suggesting they distinguished less between socially close and socially distant recipients. Unexpectedly, the cognitive-load effect on social discounting was gender-specific: while social discounting was strongly dependent on cognitive load in men, women were nearly unaffected by cognitive load manipulations. We suggest that cognitive load leads men, but not women to simplify the decision problem by neglecting the social distance information. We consider our study a good starting point for further experiments exploring the role of gender in prosocial choice.

  4. 14 CFR 29.397 - Limit pilot forces and torques.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limit pilot forces and torques. 29.397... System Loads § 29.397 Limit pilot forces and torques. (a) Except as provided in paragraph (b) of this section, the limit pilot forces are as follows: (1) For foot controls, 130 pounds. (2) For stick controls...

  5. 14 CFR 29.397 - Limit pilot forces and torques.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Limit pilot forces and torques. 29.397... System Loads § 29.397 Limit pilot forces and torques. (a) Except as provided in paragraph (b) of this section, the limit pilot forces are as follows: (1) For foot controls, 130 pounds. (2) For stick controls...

  6. 14 CFR 23.397 - Limit control forces and -torques.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Limit control forces and -torques. 23.397... Control Surface and System Loads § 23.397 Limit control forces and -torques. (a) In the control surface... limit pilot forces and torques are as follows: Control Maximum forces or torques for design...

  7. 14 CFR 23.397 - Limit control forces and -torques.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Limit control forces and -torques. 23.397... Control Surface and System Loads § 23.397 Limit control forces and -torques. (a) In the control surface... limit pilot forces and torques are as follows: Control Maximum forces or torques for design...

  8. 14 CFR 23.397 - Limit control forces and -torques.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Limit control forces and -torques. 23.397... Control Surface and System Loads § 23.397 Limit control forces and -torques. (a) In the control surface... limit pilot forces and torques are as follows: Control Maximum forces or torques for design...

  9. 14 CFR 29.397 - Limit pilot forces and torques.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Limit pilot forces and torques. 29.397... System Loads § 29.397 Limit pilot forces and torques. (a) Except as provided in paragraph (b) of this section, the limit pilot forces are as follows: (1) For foot controls, 130 pounds. (2) For stick...

  10. 14 CFR 27.397 - Limit pilot forces and torques.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Limit pilot forces and torques. 27.397... System Loads § 27.397 Limit pilot forces and torques. (a) Except as provided in paragraph (b) of this section, the limit pilot forces are as follows: (1) For foot controls, 130 pounds. (2) For stick...

  11. 14 CFR 27.397 - Limit pilot forces and torques.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Limit pilot forces and torques. 27.397... System Loads § 27.397 Limit pilot forces and torques. (a) Except as provided in paragraph (b) of this section, the limit pilot forces are as follows: (1) For foot controls, 130 pounds. (2) For stick...

  12. 14 CFR 29.397 - Limit pilot forces and torques.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Limit pilot forces and torques. 29.397... System Loads § 29.397 Limit pilot forces and torques. (a) Except as provided in paragraph (b) of this section, the limit pilot forces are as follows: (1) For foot controls, 130 pounds. (2) For stick...

  13. 14 CFR 27.397 - Limit pilot forces and torques.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Limit pilot forces and torques. 27.397... System Loads § 27.397 Limit pilot forces and torques. (a) Except as provided in paragraph (b) of this section, the limit pilot forces are as follows: (1) For foot controls, 130 pounds. (2) For stick...

  14. Load relaxation of olivine single crystals

    NASA Astrophysics Data System (ADS)

    Cooper, Reid F.; Stone, Donald S.; Plookphol, Thawatchai

    2016-10-01

    Single crystals of ferromagnesian olivine (San Carlos, AZ, peridot; Fo88-90) have been deformed in both uniaxial creep and load relaxation under conditions of ambient pressure, T = 1500°C and pO2 = 10-10 atm; creep stresses were in the range 40 ≤ σ1 (MPa) ≤ 220. The crystals were oriented such that the applied stress was parallel to [011]c, which promotes single slip on the slowest slip system in olivine, (010)[001]. The creep rates at steady state match well the results of earlier investigators, as does the stress sensitivity (a power law exponent of n = 3.6). Dislocation microstructures, including spatial distribution of low-angle (subgrain) boundaries, additionally confirm previous investigations. Inverted primary creep (an accelerating strain rate with an increase in stress) was observed. Load relaxation, however, produced a singular response—a single hardness curve—regardless of the magnitude of creep stress or total accumulated strain preceding relaxation. The log stress versus log strain rate data from load-relaxation and creep experiments overlap to within experimental error. The load-relaxation behavior is distinctly different than that described for other crystalline solids, where the flow stress is affected strongly by work hardening such that a family of distinct hardness curves is generated, which are related by a scaling function. The response of olivine for the conditions studied, we argue, indicates flow that is rate limited by dislocation glide, reflecting specifically a high intrinsic lattice resistance (Peierls stress).

  15. Lower limb loading in step aerobic dance.

    PubMed

    Wu, H-W; Hsieh, H-M; Chang, Y-W; Wang, L-H

    2012-11-01

    Participation in aerobic dance is associated with a number of lower extremity injuries, and abnormal joint loading seems to be a factor in these. However, information on joint loading is limited. The purpose of this study was to investigate the kinetics of the lower extremity in step aerobic dance and to compare the differences of high-impact and low-impact step aerobic dance in 4 aerobic movements (mambo, kick, L step and leg curl). 18 subjects were recruited for this study. High-impact aerobic dance requires a significantly greater range of motion, joint force and joint moment than low-impact step aerobic dance. The peak joint forces and moments in high-impact step aerobic dance were found to be 1.4 times higher than in low-impact step aerobic dance. Understanding the nature of joint loading may help choreographers develop dance combinations that are less injury-prone. Furthermore, increased knowledge about joint loading may be helpful in lowering the risk of injuries in aerobic dance instructors and students.

  16. Low-Load Space Conditioning Needs Assessment

    SciTech Connect

    Puttagunta, Srikanth

    2015-05-19

    Heating, ventilating, and air-conditioning (HVAC) equipment must be right-sized to ensure energy performance and comfort. With limited low-load options in the HVAC market, many new-construction housing units are being fitted with oversized equipment that creates system efficiency, comfort, and cost penalties. To bridge the gap between currently available HVAC equipment that is oversized or inefficient and the rising demand for low-load HVAC equipment in the marketplace, HVAC equipment manufacturers need to be fully aware of the needs of the multifamily building and attached single-family (duplex and townhouse) home market. Over the past decade, Steven Winter Associates, Inc. (SWA) has provided certification and consulting services for hundreds of housing projects and has accrued a large pool of data that describe multifamily and attached single-family home characteristics. The U.S. Department of Energy’s Building America research team Consortium for Advanced Residential Buildings (CARB) compiled and analyzed these data to outline the characteristics of low-load dwellings such as the heating and cooling design loads.

  17. Report of the US Nuclear Regulatory Commission Piping Review Committee. Volume 4. Evaluation of other loads and load combinations

    SciTech Connect

    Not Available

    1984-12-01

    Six topical areas were covered by the Task Group on Other Dynamic Loads and Load Combinations as described below: Event Combinations - dealing with the potential simultaneous occurrence of earthquakes, pipe ruptures, and water hammer events in the piping design basis; Response Combinations - dealing with multiply supported piping with independent inputs, the sequence of combinations between spacial and modal components of response, and the treatment of high frequency modes in combination with low frequency modal responses; Stress Limits/Dynamic Allowables - dealing with inelastic allowables for piping and strain rate effects; Water Hammer Loadings - dealing with code and design specifications for these loadings and procedures for identifying potential water hammer that could affect safety; Relief Valve Opening and Closing Loads - dealing with the adequacy of analytical tools for predicting the effects of these events and, in addition, with estimating effective cycles for fatigue evaluations; and Piping Vibration Loads - dealing with evaluation procedures for estimating other than seismic vibratory loads, the need to consider reciprocating and rotary equipment vibratory loads, and high frequency vibratory loads. NRC staff recommendations or regulatory changes and additional study appear in this report.

  18. Capillary Limit in a Loop Heat Pipe with Dual Evaporators

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Birur, Gajanana; Obenschain, Arthur F. (Technical Monitor)

    2002-01-01

    This paper describes a study on the capillary limit of a loop heat pipe (LHP) with two evaporators and two condensers. Both theoretical analysis and experimental investigation are conducted. Tests include heat load to one evaporator only, even heat loads to both evaporators and uneven heat load to both evaporators. Results show that after the capillary limit is exceeded, vapor will penetrate through the wick of the weaker evaporator and the compensation chamber (CC) of that evaporator will control the loop operating temperature regardless of which CC has been in control prior to the event Because the evaporator can tolerate vapor bubbles, the loop may continue to work and reach a new steady state at a higher operating temperature. The loop may even function with a modest increase in the heat load past the capillary limit With a heat load to only one evaporator, the capillary limit can be identified by rapid increases in the operating temperature and in the temperature difference between the evaporator and the CC. However, it is more difficult to tell when the capillary limit is exceeded if heat loads are applied to both evaporators. In all cases, the loop can recover by reducing the heat load to the loop.

  19. THE RELATIONSHIP BETWEEN LAND-BASED NITROGEN LOADING AND EELGRASS EXTENT FOR EMBAYMENTS IN SOUTHERN NEW ENGLAND: INITIAL MODEL CONSTRUCTION

    EPA Science Inventory

    This report outlines research results of the US EPA Atlantic Ecology Division in fulfilling the National Health and Environmental Effects Laboratory's Aquatic Stressors Nutrient Program's charge to develop nutrient load-ecological response models useful in setting loading limits ...

  20. Metal-loaded organic scintillators for neutrino physics

    SciTech Connect

    Buck, Christian; Yeh, Minfang

    2016-08-03

    Organic liquid scintillators are used in many neutrino physics experiments of the past and present. In particular for low energy neutrinos when realtime and energy information are required, liquid scintillators have several advantages compared to other technologies. In many cases the organic liquid needs to be loaded with metal to enhance the neutrino signal over background events. Several metal loaded scintillators of the past suffered from chemical and optical instabilities, limiting the performance of these neutrino detectors. Different ways of metal loading are described in the article with a focus on recent techniques providing metal loaded scintillators that can be used under stable conditions for many years even in ton scale experiments. Lastly, we review applications of metal loaded scintillators in neutrino experiments and compare the performance as well as the prospects of different scintillator types.

  1. Metal-loaded organic scintillators for neutrino physics

    DOE PAGES

    Buck, Christian; Yeh, Minfang

    2016-08-03

    Organic liquid scintillators are used in many neutrino physics experiments of the past and present. In particular for low energy neutrinos when realtime and energy information are required, liquid scintillators have several advantages compared to other technologies. In many cases the organic liquid needs to be loaded with metal to enhance the neutrino signal over background events. Several metal loaded scintillators of the past suffered from chemical and optical instabilities, limiting the performance of these neutrino detectors. Different ways of metal loading are described in the article with a focus on recent techniques providing metal loaded scintillators that can bemore » used under stable conditions for many years even in ton scale experiments. Lastly, we review applications of metal loaded scintillators in neutrino experiments and compare the performance as well as the prospects of different scintillator types.« less

  2. Metal-loaded organic scintillators for neutrino physics

    SciTech Connect

    Buck, Christian; Yeh, Minfang

    2016-08-03

    Organic liquid scintillators are used in many neutrino physics experiments of the past and present. In particular for low energy neutrinos when realtime and energy information are required, liquid scintillators have several advantages compared to other technologies. In many cases the organic liquid needs to be loaded with metal to enhance the neutrino signal over background events. Several metal loaded scintillators of the past suffered from chemical and optical instabilities, limiting the performance of these neutrino detectors. Different ways of metal loading are described in the article with a focus on recent techniques providing metal loaded scintillators that can be used under stable conditions for many years even in ton scale experiments. Lastly, we review applications of metal loaded scintillators in neutrino experiments and compare the performance as well as the prospects of different scintillator types.

  3. Metal-loaded organic scintillators for neutrino physics

    NASA Astrophysics Data System (ADS)

    Buck, Christian; Yeh, Minfang

    2016-09-01

    Organic liquid scintillators are used in many neutrino physics experiments of the past and present. In particular for low energy neutrinos when realtime and energy information are required, liquid scintillators have several advantages compared to other technologies. In many cases the organic liquid needs to be loaded with metal to enhance the neutrino signal over background events. Several metal loaded scintillators of the past suffered from chemical and optical instabilities, limiting the performance of these neutrino detectors. Different ways of metal loading are described in the article with a focus on recent techniques providing metal loaded scintillators that can be used under stable conditions for many years even in ton scale experiments. Applications of metal loaded scintillators in neutrino experiments are reviewed and the performance as well as the prospects of different scintillator types are compared.

  4. Predicting physiological capacity of human load carriage - a review.

    PubMed

    Drain, Jace; Billing, Daniel; Neesham-Smith, Daniel; Aisbett, Brad

    2016-01-01

    This review article aims to evaluate a proposed maximum acceptable work duration model for load carriage tasks. It is contended that this concept has particular relevance to physically demanding occupations such as military and firefighting. Personnel in these occupations are often required to perform very physically demanding tasks, over varying time periods, often involving load carriage. Previous research has investigated concepts related to physiological workload limits in occupational settings (e.g. industrial). Evidence suggests however, that existing (unloaded) workload guidelines are not appropriate for load carriage tasks. The utility of this model warrants further work to enable prediction of load carriage durations across a range of functional workloads for physically demanding occupations. If the maximum duration for which personnel can physiologically sustain a load carriage task could be accurately predicted, commanders and supervisors could better plan for and manage tasks to ensure operational imperatives were met whilst minimising health risks for their workers.

  5. Preliminary analysis of performance and loads data from the 2-megawatt mod-1 wind turbine generator

    NASA Technical Reports Server (NTRS)

    Spera, D. A.; Viterna, L. A.; Richards, T. R.; Neustadter, H. E.

    1979-01-01

    Preliminary test data on output power versus wind speed, rotor blade loads, system dynamic behavior, and start-stop characteristics on the Mod-1 wind turbine generator are presented. These data were analyzed statistically and are compared with design predictions of system performance and loads. To date, the Mod-1 wind turbine generator has produced up to 1.5 MW of power, with a measured power versus wind speed curve which agrees closely with design. Blade loads were measured at wind speeds up to 14 m/s and also during rapid shutdowns. Peak transient loads during the most severe shutdowns are less than the design limit loads. On the inboard blade sections, fatigue loads are approximately equal to the design cyclic loads. On the outboard blade sections, however, measured cyclic loads are significantly larger than design values, but they do not appear to exceed fatigue allowable loads as yet.

  6. Centaur Standard Shroud (CSS) static ultimate load structural tests

    NASA Technical Reports Server (NTRS)

    1975-01-01

    A series of tests were conducted on the jettisonable metallic shroud used on the Titan/Centaur launch vehicle to verify its structural capabilities and to evaluate its structural interaction with the Centaur stage. A flight configured shroud and the interfacing Titan/Centaur structural assemblies were subjected to tests consisting of combinations of applied axial and shear loads to design ultimate values, including a set of tests on thermal conditions and two dynamic response tests to verify the analytical stiffness model. The strength capabilities were demonstrated at ultimate (125 percent of design limit) loads. It was also verified that the spring rate of the flight configured shroud-to-Centaur forward structural deflections of the specimen became nonlinear, as expected, above limit load values. This test series qualification program verified that the Titan/Centaur shroud and the Centaur and Titan interface components are qualified structurally at design ultimate loads.

  7. Cooling loads in laboratories

    SciTech Connect

    Wilkins, C.K.; Cook, M.R.

    1999-07-01

    The heating, ventilating, and air-conditioning (HVAC) system for a laboratory must be designed with consideration for safety, air cleanliness, and space temperature. The primary safety concern is to ensure proper coordination between fume hood exhaust and makeup air supply. Air cleanliness is maintained by properly filtering supply air, by delivering adequate room air changes, and by ensuring proper pressure relationships between the laboratory and adjacent spaces. Space temperature is maintained by supplying enough cooling air to offset the amount of heat generated in the room. Each of these factors must be considered, and the one that results in the largest ventilation rate is used to establish the supply and exhaust airflows. The project described in this paper illustrates a case where cooling load is the determining factor in the sizing of the air systems.

  8. Offshore tanker loading system

    SciTech Connect

    Baan, J. de; Heijst, W.J. van.

    1994-01-04

    The present invention relates to an improved flexible loading system which provides fluid communication between a subsea pipeline and a surface vessel including a hose extending from the subsea pipeline to a first buoyancy tank, a second hose extending from the first buoyancy tank to a central buoyancy tank, a second buoyancy tank, means connecting said second buoyancy tank to the sea floor and to the central buoyancy tank whereby the forces exerted on said central buoyant tank by said second hose and said connecting means are balanced to cause said central buoyancy tank to maintain a preselected position, a riser section extending upwardly from said central buoyancy tank and means on the upper termination for engagement by a vessel on the surface to raise said upper termination onto the vessel to complete the communication for moving fluids between the subsea pipeline and the vessel. In one form the means for connecting between the sea floor to the second buoyancy tank includes an anchor on the sea floor and lines extending from the anchor to the second buoyancy tank and from the second buoyancy tank to the central buoyancy tank. In another form of the invention the means for connecting is a third hose extending from a second subsea pipeline to the second buoyancy tank and a fourth hose extending from the second buoyancy tank to the central buoyancy tank. The central buoyancy tank is preferred to be maintained at a level below the water surface which allows full movement of the vessel while connected to the riser section. A swivel may be positioned in the riser section and a pressure relief system may be included in the loading system to protect it from sudden excess pressures. 17 figs.

  9. Optimal Control Allocation with Load Sensor Feedback for Active Load Suppression, Flight-Test Performance

    NASA Technical Reports Server (NTRS)

    Miller, Christopher J.; Goodrick, Dan

    2017-01-01

    The problem of control command and maneuver induced structural loads is an important aspect of any control system design. The aircraft structure and the control architecture must be designed to achieve desired piloted control responses while limiting the imparted structural loads. The classical approach is to utilize high structural margins, restrict control surface commands to a limited set of analyzed combinations, and train pilots to follow procedural maneuvering limitations. With recent advances in structural sensing and the continued desire to improve safety and vehicle fuel efficiency, it is both possible and desirable to develop control architectures that enable lighter vehicle weights while maintaining and improving protection against structural damage. An optimal control technique has been explored and shown to achieve desirable vehicle control performance while limiting sensed structural loads to specified values. This technique has been implemented and flown on the National Aeronautics and Space Administration Full-scale Advanced Systems Testbed aircraft. The flight tests illustrate that the approach achieves the desired performance and show promising potential benefits. The flights also uncovered some important issues that will need to be addressed for production application.

  10. Mars Exploration Rover airbag landing loads testing and analsysis

    NASA Technical Reports Server (NTRS)

    Adams, Douglas S.

    2004-01-01

    This paper presents a summary of the testing and analysis used to quantify the expected airbag landing loads for the Mars Exploration Rovers. The airbag drop test setup, lander instrumentation, and the test data reduction method are discussed in order to provide an understanding of the empirical loads. A set of limiting cases that bound the empirical data are developed for use in finite element modeling of the lander and rover models.

  11. Development of fatigue loading spectra

    SciTech Connect

    Potter, J.M.; Watanabe, R.T.

    1989-01-01

    The present work on fatigue-loading spectra encompasses the current status of standardized stress-time histories, European approaches to standard loading spectrum development, transport aircraft airframe fatigue test spectra, the TURBISTAN fatigue-loading standard for fighter-aircraft engine disks, an automated procedure for the creation of flight-by-flight spectra, and the development of a wave-action standard history for fatigue testing relevant to tubular structures in the North Sea. Also treated is the use of the TURBISTAN mission spectra to evaluate fatigue crack growth in a rotating disk, fatigue-spectra development for airborne stores, a simplified analysis of fatigue-loading spectra, variable-amplitude load models for fatigue-damage crack growth, the tracking time service histories for multiaxis fatigue problems, and the compilation of procedures for fatigue crack propagation testing under complex load sequences.

  12. Stochastic load-redistribution model for cascading failure propagation.

    PubMed

    Lehmann, Jörg; Bernasconi, Jakob

    2010-03-01

    A class of probabilistic models for cascading failure propagation in interconnected systems is proposed. The models are able to represent important physical characteristics of realistic load-redistribution mechanisms, e.g., that the load increments after a failure depend on the load of the failing element and that they may be distributed nonuniformly among the remaining elements. In the limit of large system sizes, the models are solved analytically in terms of generalized branching processes, and the failure propagation properties of a prototype example are analyzed in detail.

  13. Evaluation of limb load asymmetry using two new mathematical models.

    PubMed

    Kumar, Senthil N S; Omar, Baharudin; Joseph, Leonard H; Htwe, Ohnmar; Jagannathan, K; Hamdan, Nor M Y; Rajalakshmi, D

    2014-09-25

    Quantitative measurement of limb loading is important in orthopedic and neurological rehabilitation. In current practice, mathematical models such as Symmetry index (SI), Symmetry ratio (SR), and Symmetry angle (SA) are used to quantify limb loading asymmetry. Literatures have identified certain limitations with the above mathematical models. Hence this study presents two new mathematical models Modified symmetry index (MSI) and Limb loading error (LLE) that would address these limitations. Furthermore, the current mathematical models were compared against the new model with the goal of achieving a better model. This study uses hypothetical data to simulate an algorithmic preliminary computational measure to perform with all numerical possibilities of even and uneven limb loading that can occur in human legs. Descriptive statistics are used to interpret the limb loading patterns: symmetry, asymmetry and maximum asymmetry. The five mathematical models were similar in analyzing symmetry between limbs. However, for asymmetry and maximum asymmetry data, the SA and SR values do not give any meaningful interpretation, and SI gives an inflated value. The MSI and LLE are direct, easy to interpret and identify the loading patterns with the side of asymmetry. The new models are notable as they quantify the amount and side of asymmetry under different loading patterns.

  14. Efficient field testing for load rating railroad bridges

    NASA Astrophysics Data System (ADS)

    Schulz, Jeffrey L.; Brett C., Commander

    1995-06-01

    As the condition of our infrastructure continues to deteriorate, and the loads carried by our bridges continue to increase, an ever growing number of railroad and highway bridges require load limits. With safety and transportation costs at both ends of the spectrum. the need for accurate load rating is paramount. This paper describes a method that has been developed for efficient load testing and evaluation of short- and medium-span bridges. Through the use of a specially-designed structural testing system and efficient load test procedures, a typical bridge can be instrumented and tested at 64 points in less than one working day and with minimum impact on rail traffic. Various techniques are available to evaluate structural properties and obtain a realistic model. With field data, a simple finite element model is 'calibrated' and its accuracy is verified. Appropriate design and rating loads are applied to the resulting model and stress predictions are made. This technique has been performed on numerous structures to address specific problems and to provide accurate load ratings. The merits and limitations of this approach are discussed in the context of actual examples of both rail and highway bridges that were tested and evaluated.

  15. SLUDGE TREATMENT PROJECT COST COMPARISON BETWEEN HYDRAULIC LOADING AND SMALL CANISTER LOADING CONCEPTS

    SciTech Connect

    GEUTHER J; CONRAD EA; RHOADARMER D

    2009-08-24

    The Sludge Treatment Project (STP) is considering two different concepts for the retrieval, loading, transport and interim storage of the K Basin sludge. The two design concepts under consideration are: (1) Hydraulic Loading Concept - In the hydraulic loading concept, the sludge is retrieved from the Engineered Containers directly into the Sludge Transport and Storage Container (STSC) while located in the STS cask in the modified KW Basin Annex. The sludge is loaded via a series of transfer, settle, decant, and filtration return steps until the STSC sludge transportation limits are met. The STSC is then transported to T Plant and placed in storage arrays in the T Plant canyon cells for interim storage. (2) Small Canister Concept - In the small canister concept, the sludge is transferred from the Engineered Containers (ECs) into a settling vessel. After settling and decanting, the sludge is loaded underwater into small canisters. The small canisters are then transferred to the existing Fuel Transport System (FTS) where they are loaded underwater into the FTS Shielded Transfer Cask (STC). The STC is raised from the basin and placed into the Cask Transfer Overpack (CTO), loaded onto the trailer in the KW Basin Annex for transport to T Plant. At T Plant, the CTO is removed from the transport trailer and placed on the canyon deck. The CTO and STC are opened and the small canisters are removed using the canyon crane and placed into an STSC. The STSC is closed, and placed in storage arrays in the T Plant canyon cells for interim storage. The purpose of the cost estimate is to provide a comparison of the two concepts described.

  16. Dynamic load balancing of applications

    DOEpatents

    Wheat, S.R.

    1997-05-13

    An application-level method for dynamically maintaining global load balance on a parallel computer, particularly on massively parallel MIMD computers is disclosed. Global load balancing is achieved by overlapping neighborhoods of processors, where each neighborhood performs local load balancing. The method supports a large class of finite element and finite difference based applications and provides an automatic element management system to which applications are easily integrated. 13 figs.

  17. Structural dynamics payload loads estimates

    NASA Technical Reports Server (NTRS)

    Engels, R. C.

    1982-01-01

    Methods for the prediction of loads on large space structures are discussed. Existing approaches to the problem of loads calculation are surveyed. A full scale version of an alternate numerical integration technique to solve the response part of a load cycle is presented, and a set of short cut versions of the algorithm developed. The implementation of these techniques using the software package developed is discussed.

  18. Dynamic load balancing of applications

    DOEpatents

    Wheat, Stephen R.

    1997-01-01

    An application-level method for dynamically maintaining global load balance on a parallel computer, particularly on massively parallel MIMD computers. Global load balancing is achieved by overlapping neighborhoods of processors, where each neighborhood performs local load balancing. The method supports a large class of finite element and finite difference based applications and provides an automatic element management system to which applications are easily integrated.

  19. System Measures Loads In Bolts

    NASA Technical Reports Server (NTRS)

    Allison, Sidney G.

    1994-01-01

    Improved technique for ultrasonic nondestructive measurement of loads in bolts involves use of pulsed phase-locked loop interferometer. Provides for correction of errors and for automatic readout of loads in bolts. Actual bolt load measured, using transducers rebonded after bolts tightened. Calibration block and thermometer added. Technique applicable to critical fasteners in aerospace applications, nuclear reactors, petroleum and other chemical processing plants, steel bridges, and other structures.

  20. Dynamic Strength Ceramic Nanocomposites Under Pulse Loading

    NASA Astrophysics Data System (ADS)

    Skripnyak, Evgeniya G.; Skripnyak, Vladimir V.; Vaganova, Irina K.; Skripnyak, Vladimir A.

    2015-06-01

    Multi-scale computer simulation approach has been applied to research of strength of nanocomposites under dynamic loading. The influence of mesoscopic substructures on the dynamic strength of ceramic and hybrid nanocomposites, which can be formed using additive manufacturing were numerically investigated. At weak shock wave loadings the shear strength and the spall strength of ceramic and hybrid nanocomposites depends not only phase concentration and porosity, but size parameters of skeleton substructures. The influence of skeleton parameter on the shear strength and the spall strength of ceramic nanocomposites with the same concentration of phases decreases with increasing amplitude of the shock pulse of microsecond duration above the double amplitude of the Hugoniot elastic limit of nanocomposites. This research carried out in 2014 -2015 was supported by grant from The Tomsk State University Academic D.I. Mendeleev Fund Program and also Ministry of Sciences and Education of Russian Federation (State task 2014/223, project 1943, Agreement 14.132.

  1. Portable 90 degree proof loading device

    NASA Technical Reports Server (NTRS)

    Bird, R. G.; Berson, L. A. (Inventor)

    1985-01-01

    A hydraulically actuated device is described for applying a test load to a bearing or the like to prove the integrity of its mounting or staking within a bore in a housing such as gear case. To accommodate limited access situations, the device is constructed in a right angle configuration in which a hydraulic cylinder applies axial pressure to a first thrust rod assemly which includes a first thrust rod through a threated spindle driving a linearly translated cam. Cam follower wheel transfers the translation to a second thrust rod assembly which includes a horizontal shaft and a spindle within a cross-arm housing portion and a tubular housing portion. The same second thrust direction applies the bearing loading in either of two directions depending upon the shape of the interface parts. The interface parts can bear on the bearing from either side with respect to the bearing mounting structural part.

  2. Portable 90 degree proof loading device

    NASA Astrophysics Data System (ADS)

    Bird, R. G.; Berson, L. A.

    1985-12-01

    A hydraulically actuated device is described for applying a test load to a bearing or the like to prove the integrity of its mounting or staking within a bore in a housing such as gear case. To accommodate limited access situations, the device is constructed in a right angle configuration in which a hydraulic cylinder applies axial pressure to a first thrust rod assemly which includes a first thrust rod through a threated spindle driving a linearly translated cam. Cam follower wheel transfers the translation to a second thrust rod assembly which includes a horizontal shaft and a spindle within a cross-arm housing portion and a tubular housing portion. The same second thrust direction applies the bearing loading in either of two directions depending upon the shape of the interface parts. The interface parts can bear on the bearing from either side with respect to the bearing mounting structural part.

  3. Transient loads analysis for space flight applications

    NASA Technical Reports Server (NTRS)

    Thampi, S. K.; Vidyasagar, N. S.; Ganesan, N.

    1992-01-01

    A significant part of the flight readiness verification process involves transient analysis of the coupled Shuttle-payload system to determine the low frequency transient loads. This paper describes a methodology for transient loads analysis and its implementation for the Spacelab Life Sciences Mission. The analysis is carried out using two major software tools - NASTRAN and an external FORTRAN code called EZTRAN. This approach is adopted to overcome some of the limitations of NASTRAN's standard transient analysis capabilities. The method uses Data Recovery Matrices (DRM) to improve computational efficiency. The mode acceleration method is fully implemented in the DRM formulation to recover accurate displacements, stresses, and forces. The advantages of the method are demonstrated through a numerical example.

  4. System ID modern control algorithms for active aerodynamic load control and impact on gearbox loading.

    SciTech Connect

    Berg, Jonathan Charles; Halse, Chris; Crowther, Ashley; Barlas, Thanasis; Wilson, David Gerald; Berg, Dale E.; Resor, Brian Ray

    2010-06-01

    Prior work on active aerodynamic load control (AALC) of wind turbine blades has demonstrated that appropriate use of this technology has the potential to yield significant reductions in blade loads, leading to a decrease in wind cost of energy. While the general concept of AALC is usually discussed in the context of multiple sensors and active control devices (such as flaps) distributed over the length of the blade, most work to date has been limited to consideration of a single control device per blade with very basic Proportional Derivative controllers, due to limitations in the aeroservoelastic codes used to perform turbine simulations. This work utilizes a new aeroservoelastic code developed at Delft University of Technology to model the NREL/Upwind 5 MW wind turbine to investigate the relative advantage of utilizing multiple-device AALC. System identification techniques are used to identify the frequencies and shapes of turbine vibration modes, and these are used with modern control techniques to develop both Single-Input Single-Output (SISO) and Multiple-Input Multiple-Output (MIMO) LQR flap controllers. Comparison of simulation results with these controllers shows that the MIMO controller does yield some improvement over the SISO controller in fatigue load reduction, but additional improvement is possible with further refinement. In addition, a preliminary investigation shows that AALC has the potential to reduce off-axis gearbox loads, leading to reduced gearbox bearing fatigue damage and improved lifetimes.

  5. Effect of load carriage on lumbar spine kinematics.

    PubMed

    Rodríguez-Soto, Ana E; Jaworski, Rebecca; Jensen, Andrew; Niederberger, Brenda; Hargens, Alan R; Frank, Lawrence R; Kelly, Karen R; Ward, Samuel R

    2013-06-01

    Feasibility study on the acquisition of lumbar spine kinematic data from upright magnetic resonance images obtained under heavy load carrying conditions. To characterize the effect of the load on spinal kinematics of active Marines under typical load carrying conditions from a macroscopic and lumbar-level approach in active-duty US Marines. Military personnel carry heavy loads of up to 68 kg depending on duty position and nature of the mission or training; these loads are in excess of the recommended assault loads. Performance and injury associated with load carriage have been studied; however, knowledge of lumbar spine kinematic changes is still not incorporated into training. These data would provide guidance for setting load and duration limits and a tool to investigate the potential contribution of heavy load carrying on lumbar spine pathologies. Sagittal T2 magnetic resonance images of the lumbar spine were acquired on a 0.6-T upright magnetic resonance imaging scanner for 10 active-duty Marines. Each Marine was scanned without load (UN1), immediately after donning load (LO2), after 45 minutes of standing (LO3) and walking (LO4) with load, and after 45 minutes of side-lying recovery (UN5). Custom-made software was used to measure whole spine angles, intervertebral angles, and regional disc heights (L1-S1). Repeated measurements analysis of variance and post hoc Sidak tests were used to identify significant differences between tasks (α = 0.05). The position of the spine was significantly (P < 0.0001) more horizontal relative to the external reference frame and lordosis was reduced during all tasks with load. Superior levels became more lordotic, whereas inferior levels became more kyphotic. Heavy load induced lumbar spine flexion and only anterior disc and posterior intervertebral disc height changes were observed. All kinematic variables returned to baseline levels after 45 minutes of side-lying recovery. Superior and inferior lumbar levels showed different

  6. High-Power Rf Load

    DOEpatents

    Tantawi, Sami G.; Vlieks, Arnold E.

    1998-09-01

    A compact high-power RF load comprises a series of very low Q resonators, or chokes [16], in a circular waveguide [10]. The sequence of chokes absorb the RF power gradually in a short distance while keeping the bandwidth relatively wide. A polarizer [12] at the input end of the load is provided to convert incoming TE.sub.10 mode signals to circularly polarized TE.sub.11 mode signals. Because the load operates in the circularly polarized mode, the energy is uniformly and efficiently absorbed and the load is more compact than a rectangular load. Using these techniques, a load having a bandwidth of 500 MHz can be produced with an average power dissipation level of 1.5 kW at X-band, and a peak power dissipation of 100 MW. The load can be made from common lossy materials, such as stainless steel, and is less than 15 cm in length. These techniques can also produce loads for use as an alternative to ordinary waveguide loads in small and medium RF accelerators, in radar systems, and in other microwave applications. The design is easily scalable to other RF frequencies and adaptable to the use of other lossy materials.

  7. In vitro loading of apoferritin.

    PubMed

    de Silva, D; Miller, D M; Reif, D W; Aust, S D

    1992-03-01

    This study compared the effect of loading apoferritin either with ferrous ammonium sulfate in various buffers or with ceruloplasmin and chelated ferrous iron. It was shown that loading of apoferritin with ferrous ammonium sulfate was dependent on buffer and pH, and was directly related to the rate of iron autoxidation. The ceruloplasmin-dependent loading of apoferritin, however, was unaffected by these factors. Isoelectric focusing and amino acid analysis of the differently loaded ferritins showed that ferrous ammonium sulfate loading of apoferritin resulted in the depletion of the basic amino acids, lysine and histidine, probably as a result of protein oxidation. No significant differences in amino acid composition was noted for ceruloplasmin-loaded ferritin. Furthermore, ferritin loaded with ferrous ammonium sulfate released more iron than either native or ceruloplasmin-loaded ferritin when either paraquat or EDTA was used as an iron mobilizing agent. We suggest that the loading of apoferritin with ferrous ammonium sulfate occurred as a result of iron autoxidation and may result in oxidation of amino acids and loss of integrity of the protein, and that ceruloplasmin may act as a catalyst for the incorporation of iron into apoferritin in a manner more closely related to that occurring in vivo.

  8. Alaska Village Electric Load Calculator

    SciTech Connect

    Devine, M.; Baring-Gould, E. I.

    2004-10-01

    As part of designing a village electric power system, the present and future electric loads must be defined, including both seasonal and daily usage patterns. However, in many cases, detailed electric load information is not readily available. NREL developed the Alaska Village Electric Load Calculator to help estimate the electricity requirements in a village given basic information about the types of facilities located within the community. The purpose of this report is to explain how the load calculator was developed and to provide instructions on its use so that organizations can then use this model to calculate expected electrical energy usage.

  9. Libra: Scalable Load Balance Analysis

    SciTech Connect

    2009-09-16

    Libra is a tool for scalable analysis of load balance data from all processes in a parallel application. Libra contains an instrumentation module that collects model data from parallel applications and a parallel compression mechanism that uses distributed wavelet transforms to gather load balance model data in a scalable fashion. Data is output to files, and these files can be viewed in a GUI tool by Libra users. The GUI tool associates particular load balance data with regions for code, emabling users to view the load balance properties of distributed "slices" of their application code.

  10. Residential-appliance load characteristics

    NASA Astrophysics Data System (ADS)

    Kohler, J.

    1982-04-01

    The performance of residential photovoltaic systems in combination with energy efficient appliances is examined. The load characteristics are presented for several types of major residential appliances. Load characteristics consist of the average energy use of each appliance, the power demand while the appliance is operating, and a typical use schedule. Potential energy conserving features are investigated for each appliance and used to identify a best available model and maximum feasible energy efficient appliance. Load characteristics of these energy conserving designs are then compared with the load characteristics of a standard model. The feasibility of converting appliances to dc power for use with photovoltaic systems is also discussed.

  11. Estimating Nitrogen Loads, BMPs, and Target Loads Exceedance Risks

    EPA Science Inventory

    The Wabash River (WR) watershed, IN, drains two-thirds of the state’s 92 counties and has primarily agricultural land use. The nutrient and sediment loads of the WR significantly increase loads of the Ohio River ultimately polluting the Gulf of Mexico. The objective of this study...

  12. Estimating Nitrogen Loads, BMPs, and Target Loads Exceedance Risks

    EPA Science Inventory

    The Wabash River (WR) watershed, IN, drains two-thirds of the state’s 92 counties and has primarily agricultural land use. The nutrient and sediment loads of the WR significantly increase loads of the Ohio River ultimately polluting the Gulf of Mexico. The objective of this study...

  13. Bias and variance of planning level estimates of pollutant loads

    NASA Astrophysics Data System (ADS)

    Schwartz, Stuart S.; Naiman, Daniel Q.

    1999-11-01

    Planning level techniques typically use the product of runoff volume and a characteristic concentration to estimate mean annual contaminant loads when monitoring data are inadequate or unavailable. In contrast to the extensive literature on sampling properties, bias, and precision of loads estimated from monitoring data, the unconstrained and often inconsistent alternatives for choosing "representative" runoff volumes and concentrations for use in planning level estimates limit the opportunities of generalizing analytical results on the properties of these estimators. The ease with which these simple load estimates can be calculated belies their inherent uncertainty, motivating this examination of their bias and variability. The mean and variance of planning level load estimators are derived both under mild parametric assumptions and using a distribution free approximation. Common use of the mean, median, or geometric mean of event concentrations is shown to result, in general, in biased estimates of the mean annual load. Sensitivity analysis of the mean and variance demonstrates the need to incorporate the relative variance as well as the correlation of cumulative discharge and characteristic concentration in planning level load estimates. While analogous to load estimation from monitoring data, the results presented here are distinct and unrelated to retransformation or sampling biases that have been well documented in the river load literature. Substantive implications for regional assessments, planning, and watershed management are illustrated with a simple example drawn from Chesapeake Bay.

  14. Overview of High Power Vacuum Dry RF Load Designs

    SciTech Connect

    Krasnykh, Anatoly

    2015-08-27

    A specific feature of RF linacs based on the pulsed traveling wave (TW) mode of operation is that only a portion of the RF energy is used for the beam acceleration. The residual RF energy has to be terminated into an RF load. Higher accelerating gradients require higher RF sources and RF loads, which can stably terminate the residual RF power. RF feeders (from the RF source though the accelerating section to the load) are vacuumed to transmit multi-megawatt high power RF. This overview will outline vacuumed RF loads only. A common method to terminate multi-MW RF power is to use circulated water (or other liquid) as an absorbing medium. A solid dielectric interface (a high quality ceramic) is required to separate vacuum and liquid RF absorber mediums. Using such RF load approaches in TW linacs is troubling because there is a fragile ceramic window barrier and a failure could become catastrophic for linac vacuum and RF systems. Traditional loads comprising of a ceramic disk have limited peak and average power handling capability and are therefore not suitable for high gradient TW linacs. This overview will focus on ''vacuum dry'' or ''all-metal'' loads that do not employ any dielectric interface between vacuum and absorber. The first prototype is an original design of RF loads for the Stanford Two-Mile Accelerator.

  15. Predictive equations to estimate spinal loads in symmetric lifting tasks.

    PubMed

    Arjmand, N; Plamondon, A; Shirazi-Adl, A; Larivière, C; Parnianpour, M

    2011-01-04

    Response surface methodology is used to establish robust and user-friendly predictive equations that relate responses of a complex detailed trunk finite element biomechanical model to its input variables during sagittal symmetric static lifting activities. Four input variables (thorax flexion angle, lumbar/pelvis ratio, load magnitude, and load position) and four model responses (L4-L5 and L5-S1 disc compression and anterior-posterior shear forces) are considered. Full factorial design of experiments accounting for all combinations of input levels is employed. Quadratic predictive equations for the spinal loads at the L4-S1 disc mid-heights are obtained by regression analysis with adequate goodness-of-fit (R(2)>98%, p<0.05, and low root-mean-squared-error values compared with the range of predicted spine loads). Results indicate that intradiscal pressure values at the L4-L5 disc estimated based on the predictive equations are in close agreement with available in vivo data measured under similar loadings and postures. Combinations of input (posture and loading) variable levels that yield spine loads beyond the tolerance compression limit of 3400 N are identified using contour plots. Ergonomists and bioengineers, faced with the dilemma of using either complex but more accurate models on one hand or less accurate but simple models on the other hand, have thereby easy-to-use predictive equations that quantifies spinal loads and risk of injury under different occupational tasks of interest.

  16. Strain gage selection in loads equations using a genetic algorithm

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Traditionally, structural loads are measured using strain gages. A loads calibration test must be done before loads can be accurately measured. In one measurement method, a series of point loads is applied to the structure, and loads equations are derived via the least squares curve fitting algorithm using the strain gage responses to the applied point loads. However, many research structures are highly instrumented with strain gages, and the number and selection of gages used in a loads equation can be problematic. This paper presents an improved technique using a genetic algorithm to choose the strain gages used in the loads equations. Also presented are a comparison of the genetic algorithm performance with the current T-value technique and a variant known as the Best Step-down technique. Examples are shown using aerospace vehicle wings of high and low aspect ratio. In addition, a significant limitation in the current methods is revealed. The genetic algorithm arrived at a comparable or superior set of gages with significantly less human effort, and could be applied in instances when the current methods could not.

  17. Airworthiness Qualification Criteria for Rotorcraft with External Sling Loads

    NASA Technical Reports Server (NTRS)

    Key, David L.

    2002-01-01

    This report presents the results of a study to develop airworthiness requirements for rotorcraft with external sling loads. The report starts with a review of the various phenomena that limit external sling load operations. Specifically discussed are the rotorcraft-load aeroservoelastic stability, load-on handling qualities, effects of automatic flight control system failure, load suspension system failure, and load stability at speed. Based on past experience and treatment of these phenomena, criteria are proposed to form a package for airworthiness qualification. The desired end objective is a set of operational flight envelopes for the rotorcraft with intended loads that can be provided to the user to guide operations in the field. The specific criteria proposed are parts of ADS-33E-PRF; MIL-F-9490D, and MIL-STD-913A all applied in the context of external sling loads. The study was performed for the Directorate of Engineering, U.S. Army Aviation and Missile Command (AMCOM), as part of the contract monitored by the Aerothermodynamics Directorate, U.S. Army AMCOM.

  18. Assessment of New Load Schedules for the Machine Calibration of a Force Balance

    NASA Technical Reports Server (NTRS)

    Ulbrich, N.; Gisler, R.; Kew, R.

    2015-01-01

    New load schedules for the machine calibration of a six-component force balance are currently being developed and evaluated at the NASA Ames Balance Calibration Laboratory. One of the proposed load schedules is discussed in the paper. It has a total of 2082 points that are distributed across 16 load series. Several criteria were applied to define the load schedule. It was decided, for example, to specify the calibration load set in force balance format as this approach greatly simplifies the definition of the lower and upper bounds of the load schedule. In addition, all loads are assumed to be applied in a calibration machine by using the one-factor-at-a-time approach. At first, all single-component loads are applied in six load series. Then, three two-component load series are applied. They consist of the load pairs (N1, N2), (S1, S2), and (RM, AF). Afterwards, four three-component load series are applied. They consist of the combinations (N1, N2, AF), (S1, S2, AF), (N1, N2, RM), and (S1, S2, RM). In the next step, one four-component load series is applied. It is the load combination (N1, N2, S1, S2). Finally, two five-component load series are applied. They are the load combination (N1, N2, S1, S2, AF) and (N1, N2, S1, S2, RM). The maximum difference between loads of two subsequent data points of the load schedule is limited to 33 % of capacity. This constraint helps avoid unwanted load "jumps" in the load schedule that can have a negative impact on the performance of a calibration machine. Only loadings of the single- and two-component load series are loaded to 100 % of capacity. This approach was selected because it keeps the total number of calibration points to a reasonable limit while still allowing for the application of some of the more complex load combinations. Data from two of NASA's force balances is used to illustrate important characteristics of the proposed 2082-point calibration load schedule.

  19. Crane-Load Contact Sensor

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert; Mata, Carlos; Cox, Robert

    2005-01-01

    An electronic instrument has been developed as a prototype of a portable crane-load contact sensor. Such a sensor could be helpful in an application in which the load rests on a base in a horizontal position determined by vertical alignment pins (see Figure 1). If the crane is not positioned to lift the load precisely vertically, then the load can be expected to swing once it has been lifted clear of the pins. If the load is especially heavy, large, and/or fragile, it could hurt workers and/or damage itself and nearby objects. By indicating whether the load remains in contact with the pins when it has been lifted a fraction of the length of the pins, the crane-load contact sensor helps the crane operator determine whether it is safe to lift the load clear of the pins: If there is contact, then the load is resting against the sides of the pins and, hence, it may not be safe to lift; if contact is occasionally broken, then the load is probably not resting against the pins, so it should be safe to lift. It is assumed that the load and base, or at least the pins and the surfaces of the alignment holes in the load, are electrically conductive, so the instrument can use electrical contact to indicate mechanical contact. However, DC resistance cannot be used as an indicator of contact for the following reasons: The load and the base are both electrically grounded through cables (the load is grounded through the lifting cable of the crane) to prevent discharge of static electricity. In other words, the DC resistance between the load and the pins is always low, as though they were always in direct contact. Therefore, instead of DC resistance, the instrument utilizes the AC electrical impedance between the pins and the load. The signal frequency used in the measurement is high enough (.1 MHz) that the impedance contributed by the cables and the electrical ground network of the building in which the crane and the base are situated is significantly greater than the contact

  20. Load sensing surgical instruments.

    PubMed

    Jacq, C; Maeder, T; Ryser, P

    2009-12-01

    Force and pressure sensing technology applied to smart surgical instruments as well as implants allow to give a direct feedback of loads to the surgeon lead to better reliability and success of surgical operations. A common technology used for sensors is low-cost piezoresistive thick-film technology. However, the standard thick-film firing conditions degrade the properties of medical alloys. In order to avoid this problem, the solution is to decrease the firing temperature of thick films. This work presents the development and characterisation of low-firing thick-film systems (dielectrics, resistors and conductors), formulated to achieve chemical and thermal expansion compatibility with an austenitic stainless steel medical alloy. Adherence tests and results on electrical properties of these systems: resistance, temperature coefficient of resistance (TCR) are presented. It was found that the main issue in these systems lies in mastering the materials interactions during firing, especially at the silver-based resistor terminations. The interaction of silver, resistor and dielectric tends to give rise to highly resistive zones at the terminations, affecting reliability. This can be circumvented by post-firing the resistor terminations at a moderate temperature.