From damselflies to pterosaurs: how burst and sustainable flight performance scale with size.

PubMed

Marden, J H

1994-04-01

Recent empirical data for short-burst lift and power production of flying animals indicate that mass-specific lift and power output scale independently (lift) or slightly positively (power) with increasing size. These results contradict previous theory, as well as simple observation, which argues for degradation of flight performance with increasing size. Here, empirical measures of lift and power during short-burst exertion are combined with empirically based estimates of maximum muscle power output in order to predict how burst and sustainable performance scale with body size. The resulting model is used to estimate performance of the largest extant flying birds and insects, along with the largest flying animals known from fossils. These estimates indicate that burst flight performance capacities of even the largest extinct fliers (estimated mass 250 kg) would allow takeoff from the ground; however, limitations on sustainable power output should constrain capacity for continuous flight at body sizes exceeding 0.003-1.0 kg, depending on relative wing length and flight muscle mass.

MSFC-1700825

NASA Image and Video Library

2017-07-10

The Orion stage adapter is being positioned for lifting onto the loading platform before being loaded into NASA's Super Guppie aircraft. The adapter will be flown to Denver, Colorado for further testing.

MSFC-1700827

NASA Image and Video Library

2017-07-10

The Orion stage adapter is being positioned for lifting onto the loading platform before being loaded into NASA's Super Guppie aircraft. The adapter will be flown to Denver, Colorado for further testing.

MSFC-1700828

NASA Image and Video Library

2017-07-10

The Orion stage adapter is being positioned for lifting onto the loading platform before being loaded into NASA's Super Guppie aircraft. The adapter will be flown to Denver, Colorado for further testing.

MSFC-1700823

NASA Image and Video Library

2017-07-10

The Orion stage adapter is being positioned for lifting onto the loading platform before being loaded into NASA's Super Guppie aircraft. The adapter will be flown to Denver, Colorado for further testing.

MSFC-1700826

NASA Image and Video Library

2017-07-10

The Orion stage adapter is being positioned for lifting onto the loading platform before being loaded into NASA's Super Guppie aircraft. The adapter will be flown to Denver, Colorado for further testing.

MSFC-1700822

NASA Image and Video Library

2017-07-10

The Orion stage adapter is being positioned for lifting onto the loading platform before being loaded into NASA's Super Guppie aircraft. The adapter will be flown to Denver, Colorado for further testing.

MSFC-1700824

NASA Image and Video Library

2017-07-10

The Orion stage adapter is being positioned for lifting onto the loading platform before being loaded into NASA's Super Guppie aircraft. The adapter will be flown to Denver, Colorado for further testing.

Summary of the 2008 NASA Fundamental Aeronautics Program Sonic Boom Prediction Workshop

NASA Technical Reports Server (NTRS)

Park, Michael A.; Aftosmis, Michael J.; Campbell, Richard L.; Carter, Melissa B.; Cliff, Susan; Nangert, Linda S.

2013-01-01

The Supersonics Project of the NASA Fundamental Aeronautics Program organized an internal sonic boom workshop to evaluate near- and mid-field sonic boom prediction capability at the Fundamental Aeronautics Annual Meeting in Atlanta, Georgia on October 8, 2008. Workshop participants computed sonic boom signatures for three non-lifting bodies and two lifting configurations. A cone-cylinder, parabolic, and quartic bodies of revolution comprised the non-lifting cases. The lifting configurations were a simple 69-degree delta wing body and a complete low-boom transport configuration designed during the High Speed Research Project in the 1990s with wing, body, tail, nacelle, and boundary layer diverter components. The AIRPLANE, Cart3D, FUN3D, and USM3D ow solvers were employed with the ANET signature propagation tool, output-based adaptation, and a priori adaptation based on freestream Mach number and angle of attack. Results were presented orally at the workshop. This article documents the workshop, results, and provides context on previously available and recently developed methods.

Climate Change and Water Infrastructure in Central Asia: adaptation capacities and institutional challenges

NASA Astrophysics Data System (ADS)

Abdullaev, Iskandar; Rakhmatullaev, Shavkat

2014-05-01

The paper discusses vulnerability areas of water sector in arid Central Asia due to climate change projections with particular focus on adaptation to sustainable operation of physical infrastructure capacities (from legal, institutional and technical aspects). Two types of technical installations are the main focus of this paper, i.e., electrical lift irrigation systems and water reservoirs. The first set of electrical lift infrastructure is strategic for delivering water to water users via pumps, diversion structures, vertical drainage facilities and groundwater boreholes; on the other hand, the primarily task of second set of structures is to accumulate the water resources for sectors of economy. In Central Asia, approximately, 20-50% of irrigation water is lifted, yet major of lift structures are in very poor technical conditions coupled with ever increasing of electricity tariffs. Furthermore, useful volumes capacities of water reservoirs are being severely diminished due to bio-physical geomorphologic processes, improper operational regimes and chronic financing for special in-house sedimentation surveys. Most importantly, the key argument is that irrigation sector should internalize its adaptation efforts, i.e., integrate renewable energy technologies, energy audit programs and lastly design comprehensive investment prioritization processes and programs. Otherwise, water sector will be at great risk for continued provision of fundamental services to the public, food security and industry

Capabilities of wind tunnels with two-adaptive walls to minimize boundary interference in 3-D model testing

NASA Technical Reports Server (NTRS)

Rebstock, Rainer; Lee, Edwin E., Jr.

1989-01-01

An initial wind tunnel test was made to validate a new wall adaptation method for 3-D models in test sections with two adaptive walls. First part of the adaptation strategy is an on-line assessment of wall interference at the model position. The wall induced blockage was very small at all test conditions. Lift interference occurred at higher angles of attack with the walls set aerodynamically straight. The adaptation of the top and bottom tunnel walls is aimed at achieving a correctable flow condition. The blockage was virtually zero throughout the wing planform after the wall adjustment. The lift curve measured with the walls adapted agreed very well with interference free data for Mach 0.7, regardless of the vertical position of the wing in the test section. The 2-D wall adaptation can significantly improve the correctability of 3-D model data. Nevertheless, residual spanwise variations of wall interference are inevitable.

Adaptive Fuzzy Output-Constrained Fault-Tolerant Control of Nonlinear Stochastic Large-Scale Systems With Actuator Faults.

PubMed

Li, Yongming; Ma, Zhiyao; Tong, Shaocheng

2017-09-01

The problem of adaptive fuzzy output-constrained tracking fault-tolerant control (FTC) is investigated for the large-scale stochastic nonlinear systems of pure-feedback form. The nonlinear systems considered in this paper possess the unstructured uncertainties, unknown interconnected terms and unknown nonaffine nonlinear faults. The fuzzy logic systems are employed to identify the unknown lumped nonlinear functions so that the problems of structured uncertainties can be solved. An adaptive fuzzy state observer is designed to solve the nonmeasurable state problem. By combining the barrier Lyapunov function theory, adaptive decentralized and stochastic control principles, a novel fuzzy adaptive output-constrained FTC approach is constructed. All the signals in the closed-loop system are proved to be bounded in probability and the system outputs are constrained in a given compact set. Finally, the applicability of the proposed controller is well carried out by a simulation example.

High Order Modulation Protograph Codes

NASA Technical Reports Server (NTRS)

Nguyen, Thuy V. (Inventor); Nosratinia, Aria (Inventor); Divsalar, Dariush (Inventor)

2014-01-01

Digital communication coding methods for designing protograph-based bit-interleaved code modulation that is general and applies to any modulation. The general coding framework can support not only multiple rates but also adaptive modulation. The method is a two stage lifting approach. In the first stage, an original protograph is lifted to a slightly larger intermediate protograph. The intermediate protograph is then lifted via a circulant matrix to the expected codeword length to form a protograph-based low-density parity-check code.

Integrated propulsion/energy transfer control systems for lift-fan V/STOL aircraft. [reduction of total propulsion system and control system installation requirements

NASA Technical Reports Server (NTRS)

Deckert, W. H.; Rolls, L. S.

1974-01-01

An integrated propulsion/control system for lift-fan transport aircraft is described. System behavior from full-scale experimental and piloted simulator investigations are reported. The lift-fan transport is a promising concept for short-to-medium haul civil transportation and for other missions. The lift-fan transport concept features high cruise airspeed, favorable ride qualities, small perceived noise footprints, high utilization, transportation system flexibility, and adaptability to VTOL, V/STOL, or STOL configurations. The lift-fan transport has high direct operating costs in comparison to conventional aircraft, primarily because of propulsion system and aircraft low-speed control system installation requirements. An integrated lift-fan propulsion system/aircraft low-speed control system that reduces total propulsion system and control system installation requirements is discussed.

A Comparison of Four Item-Selection Methods for Severely Constrained CATs

ERIC Educational Resources Information Center

He, Wei; Diao, Qi; Hauser, Carl

2014-01-01

This study compared four item-selection procedures developed for use with severely constrained computerized adaptive tests (CATs). Severely constrained CATs refer to those adaptive tests that seek to meet a complex set of constraints that are often not conclusive to each other (i.e., an item may contribute to the satisfaction of several…

Variable Lifting Index (VLI): A New Method for Evaluating Variable Lifting Tasks.

PubMed

Waters, Thomas; Occhipinti, Enrico; Colombini, Daniela; Alvarez-Casado, Enrique; Fox, Robert

2016-08-01

We seek to develop a new approach for analyzing the physical demands of highly variable lifting tasks through an adaptation of the Revised NIOSH (National Institute for Occupational Safety and Health) Lifting Equation (RNLE) into a Variable Lifting Index (VLI). There are many jobs that contain individual lifts that vary from lift to lift due to the task requirements. The NIOSH Lifting Equation is not suitable in its present form to analyze variable lifting tasks. In extending the prior work on the VLI, two procedures are presented to allow users to analyze variable lifting tasks. One approach involves the sampling of lifting tasks performed by a worker over a shift and the calculation of the Frequency Independent Lift Index (FILI) for each sampled lift and the aggregation of the FILI values into six categories. The Composite Lift Index (CLI) equation is used with lifting index (LI) category frequency data to calculate the VLI. The second approach employs a detailed systematic collection of lifting task data from production and/or organizational sources. The data are organized into simplified task parameter categories and further aggregated into six FILI categories, which also use the CLI equation to calculate the VLI. The two procedures will allow practitioners to systematically employ the VLI method to a variety of work situations where highly variable lifting tasks are performed. The scientific basis for the VLI procedure is similar to that for the CLI originally presented by NIOSH; however, the VLI method remains to be validated. The VLI method allows an analyst to assess highly variable manual lifting jobs in which the task characteristics vary from lift to lift during a shift. © 2015, Human Factors and Ergonomics Society.

Motor Adaptation and Manual Transfer: Insight into the Persistent Nature of Sensorimotor Representations

ERIC Educational Resources Information Center

Green, Sharon; Grierson, Lawrence E. M.; Dubrowski, Adam; Carnahan, Heather

2010-01-01

It is well known that sensorimotor memories are built and updated through experience with objects. These representations are useful to anticipatory and feedforward control processes that preset grip and load forces during lifting. When individuals lift objects with qualities that are not congruent with their memory-derived expectations, feedback…

Revisiting the comparison between the Shack-Hartmann and the pyramid wavefront sensors via the Fisher information matrix.

PubMed

Plantet, C; Meimon, S; Conan, J-M; Fusco, T

2015-11-02

Exoplanet direct imaging with large ground based telescopes requires eXtreme Adaptive Optics that couples high-order adaptive optics and coronagraphy. A key element of such systems is the high-order wavefront sensor. We study here several high-order wavefront sensing approaches, and more precisely compare their sensitivity to noise. Three techniques are considered: the classical Shack-Hartmann sensor, the pyramid sensor and the recently proposed LIFTed Shack-Hartmann sensor. They are compared in a unified framework based on precise diffractive models and on the Fisher information matrix, which conveys the information present in the data whatever the estimation method. The diagonal elements of the inverse of the Fisher information matrix, which we use as a figure of merit, are similar to noise propagation coefficients. With these diagonal elements, so called "Fisher coefficients", we show that the LIFTed Shack-Hartmann and pyramid sensors outperform the classical Shack-Hartmann sensor. In photon noise regime, the LIFTed Shack-Hartmann and modulated pyramid sensors obtain a similar overall noise propagation. The LIFTed Shack-Hartmann sensor however provides attractive noise properties on high orders.

Optimum three-dimensional atmospheric entry from the analytical solution of Chapman's exact equations

NASA Technical Reports Server (NTRS)

Busemann, A.; Vinh, N. X.; Culp, R. D.

1974-01-01

The general solution for the optimum three-dimensional aerodynamic control of a lifting vehicle entering a planetary atmosphere is developed. A set of dimensionless variables, modified Chapman variables, is introduced. The resulting exact equations of motion, referred to as Chapman's exact equations, have the advantage that they are completely free of the physical characteristics of the vehicle. Furthermore, a completely general lift-drag relationship is used in the derivation. The results obtained apply to any type of vehicle of arbitrary weight, dimensions and shape, having an arbitrary drag polar, and entering any planetary atmosphere. The aerodynamic controls chosen are the lift coefficient and the bank angle. General optimum control laws for these controls are developed. Several earlier particular solutions are shown to be special cases of this general result. Results are valid for both free and constrained terminal position.

Incremental wind tunnel testing of high lift systems

NASA Astrophysics Data System (ADS)

Victor, Pricop Mihai; Mircea, Boscoianu; Daniel-Eugeniu, Crunteanu

2016-06-01

Efficiency of trailing edge high lift systems is essential for long range future transport aircrafts evolving in the direction of laminar wings, because they have to compensate for the low performance of the leading edge devices. Modern high lift systems are subject of high performance requirements and constrained to simple actuation, combined with a reduced number of aerodynamic elements. Passive or active flow control is thus required for the performance enhancement. An experimental investigation of reduced kinematics flap combined with passive flow control took place in a low speed wind tunnel. The most important features of the experimental setup are the relatively large size, corresponding to a Reynolds number of about 2 Million, the sweep angle of 30 degrees corresponding to long range airliners with high sweep angle wings and the large number of flap settings and mechanical vortex generators. The model description, flap settings, methodology and results are presented.

Bayesian Item Selection in Constrained Adaptive Testing Using Shadow Tests

ERIC Educational Resources Information Center

Veldkamp, Bernard P.

2010-01-01

Application of Bayesian item selection criteria in computerized adaptive testing might result in improvement of bias and MSE of the ability estimates. The question remains how to apply Bayesian item selection criteria in the context of constrained adaptive testing, where large numbers of specifications have to be taken into account in the item…

Variable Lifting Index (VLI)

PubMed Central

Waters, Thomas; Occhipinti, Enrico; Colombini, Daniela; Alvarez-Casado, Enrique; Fox, Robert

2015-01-01

Objective: We seek to develop a new approach for analyzing the physical demands of highly variable lifting tasks through an adaptation of the Revised NIOSH (National Institute for Occupational Safety and Health) Lifting Equation (RNLE) into a Variable Lifting Index (VLI). Background: There are many jobs that contain individual lifts that vary from lift to lift due to the task requirements. The NIOSH Lifting Equation is not suitable in its present form to analyze variable lifting tasks. Method: In extending the prior work on the VLI, two procedures are presented to allow users to analyze variable lifting tasks. One approach involves the sampling of lifting tasks performed by a worker over a shift and the calculation of the Frequency Independent Lift Index (FILI) for each sampled lift and the aggregation of the FILI values into six categories. The Composite Lift Index (CLI) equation is used with lifting index (LI) category frequency data to calculate the VLI. The second approach employs a detailed systematic collection of lifting task data from production and/or organizational sources. The data are organized into simplified task parameter categories and further aggregated into six FILI categories, which also use the CLI equation to calculate the VLI. Results: The two procedures will allow practitioners to systematically employ the VLI method to a variety of work situations where highly variable lifting tasks are performed. Conclusions: The scientific basis for the VLI procedure is similar to that for the CLI originally presented by NIOSH; however, the VLI method remains to be validated. Application: The VLI method allows an analyst to assess highly variable manual lifting jobs in which the task characteristics vary from lift to lift during a shift. PMID:26646300

Wavelet-based associative memory

NASA Astrophysics Data System (ADS)

Jones, Katharine J.

2004-04-01

Faces provide important characteristics of a person"s identification. In security checks, face recognition still remains the method in continuous use despite other approaches (i.e. fingerprints, voice recognition, pupil contraction, DNA scanners). With an associative memory, the output data is recalled directly using the input data. This can be achieved with a Nonlinear Holographic Associative Memory (NHAM). This approach can also distinguish between strongly correlated images and images that are partially or totally enclosed by others. Adaptive wavelet lifting has been used for Content-Based Image Retrieval. In this paper, adaptive wavelet lifting will be applied to face recognition to achieve an associative memory.

An examination of the jump-and-lift factors influencing the time to reach peak catch height during a Rugby Union lineout.

PubMed

Smith, Tiaki Brett; Hébert-Losier, Kim; McClymont, Doug

2018-05-01

The goal of an offensive Rugby Union lineout is to throw the ball in a manner that allows your team to maintain possession. Typically, the player catching the ball jumps and is lifted upwards by two teammates, reaching above the opposing player who is competing for the ball also. Despite various beliefs regarding the importance of the jumper's mass and attempted jump height, and lifters' magnitude and point of force application, there is negligible published data on the topic. The squeeze technique is one lifting method commonly employed by New Zealand teams during lineout plays, whereby the jumper initiates the jump quickly and the lifters provide assistance only once the jumper reaches 20-30 cm. While this strategy may reduce cues to the opposition, it might also constrain the jumper and lifters. We developed a model to explore how changes in the jumper's body mass and attempted jump height, and lifters' magnitude and point of force application influence the time to reach peak catch height. The magnitude of the lift force impacted the time-to-reach peak catch height the most; followed by the jumper's (attempted) jump height and body mass; and lastly, the point of lift force application.

Adjoint-Based, Three-Dimensional Error Prediction and Grid Adaptation

NASA Technical Reports Server (NTRS)

Park, Michael A.

2002-01-01

Engineering computational fluid dynamics (CFD) analysis and design applications focus on output functions (e.g., lift, drag). Errors in these output functions are generally unknown and conservatively accurate solutions may be computed. Computable error estimates can offer the possibility to minimize computational work for a prescribed error tolerance. Such an estimate can be computed by solving the flow equations and the linear adjoint problem for the functional of interest. The computational mesh can be modified to minimize the uncertainty of a computed error estimate. This robust mesh-adaptation procedure automatically terminates when the simulation is within a user specified error tolerance. This procedure for estimating and adapting to error in a functional is demonstrated for three-dimensional Euler problems. An adaptive mesh procedure that links to a Computer Aided Design (CAD) surface representation is demonstrated for wing, wing-body, and extruded high lift airfoil configurations. The error estimation and adaptation procedure yielded corrected functions that are as accurate as functions calculated on uniformly refined grids with ten times as many grid points.

Low profile, high load vertical rolling positioning stage

DOEpatents

Shu, Deming; Barraza, Juan

1996-01-01

A stage or support platform assembly for use in a synchrotron accurately positions equipment to be used in the beam line of the synchrotron. The support platform assembly includes an outer housing in which is disposed a lifting mechanism having a lifting platform or stage at its upper extremity on which the equipment is mounted. A worm gear assembly is located in the housing and is adapted to raise and lower a lifting shaft that is fixed to the lifting platform by an anti-binding connection. The lifting platform is moved vertically as the lifting shaft is moved vertically. The anti-binding connection prevents the shaft from rotating with respect to the platform, but does permit slight canting of the shaft with respect to the lifting platform so as to eliminate binding and wear due to possible tolerance mismatches. In order to ensure that the lifting mechanism does not move in a horizontal direction as it is moved vertically, at least three linear roller bearing assemblies are arranged around the outer-periphery of the lifting mechanism. One of the linear roller bearing assemblies can be adjusted so that the roller bearings apply a loading force against the lifting mechanism. Alternatively, a cam mechanism can be used to provide such a loading force.

Adaptive Fuzzy Output Constrained Control Design for Multi-Input Multioutput Stochastic Nonstrict-Feedback Nonlinear Systems.

PubMed

Li, Yongming; Tong, Shaocheng

2017-12-01

In this paper, an adaptive fuzzy output constrained control design approach is addressed for multi-input multioutput uncertain stochastic nonlinear systems in nonstrict-feedback form. The nonlinear systems addressed in this paper possess unstructured uncertainties, unknown gain functions and unknown stochastic disturbances. Fuzzy logic systems are utilized to tackle the problem of unknown nonlinear uncertainties. The barrier Lyapunov function technique is employed to solve the output constrained problem. In the framework of backstepping design, an adaptive fuzzy control design scheme is constructed. All the signals in the closed-loop system are proved to be bounded in probability and the system outputs are constrained in a given compact set. Finally, the applicability of the proposed controller is well carried out by a simulation example.

Motion Planning and Synthesis of Human-Like Characters in Constrained Environments

NASA Astrophysics Data System (ADS)

Zhang, Liangjun; Pan, Jia; Manocha, Dinesh

We give an overview of our recent work on generating naturally-looking human motion in constrained environments with multiple obstacles. This includes a whole-body motion planning algorithm for high DOF human-like characters. The planning problem is decomposed into a sequence of low dimensional sub-problems. We use a constrained coordination scheme to solve the sub-problems in an incremental manner and a local path refinement algorithm to compute collision-free paths in tight spaces and satisfy the statically stable constraint on CoM. We also present a hybrid algorithm to generate plausible motion by combing the motion computed by our planner with mocap data. We demonstrate the performance of our algorithm on a 40 DOF human-like character and generate efficient motion strategies for object placement, bending, walking, and lifting in complex environments.

Balancing Flexible Constraints and Measurement Precision in Computerized Adaptive Testing

ERIC Educational Resources Information Center

Moyer, Eric L.; Galindo, Jennifer L.; Dodd, Barbara G.

2012-01-01

Managing test specifications--both multiple nonstatistical constraints and flexibly defined constraints--has become an important part of designing item selection procedures for computerized adaptive tests (CATs) in achievement testing. This study compared the effectiveness of three procedures: constrained CAT, flexible modified constrained CAT,…

Time-varying span efficiency through the wingbeat of desert locusts.

PubMed

Henningsson, Per; Bomphrey, Richard J

2012-06-07

The flight performance of animals depends greatly on the efficacy with which they generate aerodynamic forces. Accordingly, maximum range, load-lifting capacity and peak accelerations during manoeuvres are all constrained by the efficiency of momentum transfer to the wake. Here, we use high-speed particle image velocimetry (1 kHz) to record flow velocities in the near wake of desert locusts (Schistocerca gregaria, Forskål). We use the measured flow fields to calculate time-varying span efficiency throughout the wing stroke cycle. The locusts are found to operate at a maximum span efficiency of 79 per cent, typically at a plateau of about 60 per cent for the majority of the downstroke, but at lower values during the upstroke. Moreover, the calculated span efficiencies are highest when the largest lift forces are being generated (90% of the total lift is generated during the plateau of span efficiency) suggesting that the combination of wing kinematics and morphology in locust flight perform most efficiently when doing the most work.

Optimal lifting ascent trajectories for the space shuttle

NASA Technical Reports Server (NTRS)

Rau, T. R.; Elliott, J. R.

1972-01-01

The performance gains which are possible through the use of optimal trajectories for a particular space shuttle configuration are discussed. The spacecraft configurations and aerodynamic characteristics are described. Shuttle mission payload capability is examined with respect to the optimal orbit inclination for unconstrained, constrained, and nonlifting conditions. The effects of velocity loss and heating rate on the optimal ascent trajectory are investigated.

Space Logistics: Launch Capabilities

NASA Technical Reports Server (NTRS)

Furnas, Randall B.

1989-01-01

The current maximum launch capability for the United States are shown. The predicted Earth-to-orbit requirements for the United States are presented. Contrasting the two indicates the strong National need for a major increase in Earth-to-orbit lift capability. Approximate weights for planned payloads are shown. NASA is studying the following options to meet the need for a new heavy-lift capability by mid to late 1990's: (1) Shuttle-C for near term (include growth versions); and (2) the Advanced Lauching System (ALS) for the long term. The current baseline two-engine Shuttle-C has a 15 x 82 ft payload bay and an expected lift capability of 82,000 lb to Low Earth Orbit. Several options are being considered which have expanded diameter payload bays. A three-engine Shuttle-C with an expected lift of 145,000 lb to LEO is being evaluated as well. The Advanced Launch System (ALS) is a potential joint development between the Air Force and NASA. This program is focused toward long-term launch requirements, specifically beyond the year 2000. The basic approach is to develop a family of vehicles with the same high reliability as the Shuttle system, yet offering a much greater lift capability at a greatly reduced cost (per pound of payload). The ALS unmanned family of vehicles will provide a low end lift capability equivalent to Titan IV, and a high end lift capability greater than the Soviet Energia if requirements for such a high-end vehicle are defined.In conclusion, the planning of the next generation space telescope should not be constrained to the current launch vehicles. New vehicle designs will be driven by the needs of anticipated heavy users.

38 CFR 17.157 - Definition-adaptive equipment.

Code of Federal Regulations, 2010 CFR

2010-07-01

... includes, but is not limited to, a basic automatic transmission, power steering, power brakes, power window lifts, power seats, air-conditioning equipment when necessary for the health and safety of the veteran... MEDICAL Automotive Equipment and Driver Training § 17.157 Definition-adaptive equipment. The term...

A constrained Delaunay discretization method for adaptively meshing highly discontinuous geological media

NASA Astrophysics Data System (ADS)

Wang, Yang; Ma, Guowei; Ren, Feng; Li, Tuo

2017-12-01

A constrained Delaunay discretization method is developed to generate high-quality doubly adaptive meshes of highly discontinuous geological media. Complex features such as three-dimensional discrete fracture networks (DFNs), tunnels, shafts, slopes, boreholes, water curtains, and drainage systems are taken into account in the mesh generation. The constrained Delaunay triangulation method is used to create adaptive triangular elements on planar fractures. Persson's algorithm (Persson, 2005), based on an analogy between triangular elements and spring networks, is enriched to automatically discretize a planar fracture into mesh points with varying density and smooth-quality gradient. The triangulated planar fractures are treated as planar straight-line graphs (PSLGs) to construct piecewise-linear complex (PLC) for constrained Delaunay tetrahedralization. This guarantees the doubly adaptive characteristic of the resulted mesh: the mesh is adaptive not only along fractures but also in space. The quality of elements is compared with the results from an existing method. It is verified that the present method can generate smoother elements and a better distribution of element aspect ratios. Two numerical simulations are implemented to demonstrate that the present method can be applied to various simulations of complex geological media that contain a large number of discontinuities.

Wing high-lift system with spoiler droop

NASA Astrophysics Data System (ADS)

Gubsky, Vitaly; Pavlenko, Olga; Petrov, Albert

2018-05-01

Take-off and landing regimes are becoming increasingly difficult due to the increased aircraft mass and speed and the toughening of air safety demands. The capabilities of conventional single-slotted or multi-slotted flaps are limited. This problem can be resolved by the deflection or bending of the tail section, which forms a potential flow that results in an increase in the lift component at high angles of attack. Different versions of the flap on a two-part high-lift device with a spoiler are examined. Calculations show that the application of an adaptive high-lift system with spoiler droop to an aircraft increases the lift coefficient by as much as 15%. Aircraft model experiments indicated that a δs = 5° deflection of the trailing edge increases the lift coefficient by 11% - 13%. Setting the propeller load coefficient to B = 1 (thrust/velocity factor propeller area) under take-off δf = 20° and landing δf = 35° configurations increases the efficiency of a lift coefficient by 25% and 36%, respectively. The application of spoiler droop and leading edge modifications of the wing expands the operational range of angles of attack and increases the lift coefficient by 10% at a small intensity (B = 0.5). It is concluded that the application of spoiler droop to high-lift system allows improvement of the wing properties under take-off and landing regimes of various types.

Development of Variable Camber Continuous Trailing Edge Flap for Performance Adaptive Aeroelastic Wing

NASA Technical Reports Server (NTRS)

Nguyen, Nhan; Kaul, Upender; Lebofsky, Sonia; Ting, Eric; Chaparro, Daniel; Urnes, James

2015-01-01

This paper summarizes the recent development of an adaptive aeroelastic wing shaping control technology called variable camber continuous trailing edge flap (VCCTEF). As wing flexibility increases, aeroelastic interactions with aerodynamic forces and moments become an increasingly important consideration in aircraft design and aerodynamic performance. Furthermore, aeroelastic interactions with flight dynamics can result in issues with vehicle stability and control. The initial VCCTEF concept was developed in 2010 by NASA under a NASA Innovation Fund study entitled "Elastically Shaped Future Air Vehicle Concept," which showed that highly flexible wing aerodynamic surfaces can be elastically shaped in-flight by active control of wing twist and bending deflection in order to optimize the spanwise lift distribution for drag reduction. A collaboration between NASA and Boeing Research & Technology was subsequently funded by NASA from 2012 to 2014 to further develop the VCCTEF concept. This paper summarizes some of the key research areas conducted by NASA during the collaboration with Boeing Research and Technology. These research areas include VCCTEF design concepts, aerodynamic analysis of VCCTEF camber shapes, aerodynamic optimization of lift distribution for drag minimization, wind tunnel test results for cruise and high-lift configurations, flutter analysis and suppression control of flexible wing aircraft, and multi-objective flight control for adaptive aeroelastic wing shaping control.

Spatially modulated laser pulses for printing electronics.

PubMed

Auyeung, Raymond C Y; Kim, Heungsoo; Mathews, Scott; Piqué, Alberto

2015-11-01

The use of a digital micromirror device (DMD) in laser-induced forward transfer (LIFT) is reviewed. Combining this technique with high-viscosity donor ink (silver nanopaste) results in laser-printed features that are highly congruent in shape and size to the incident laser beam spatial profile. The DMD empowers LIFT to become a highly parallel, rapidly reconfigurable direct-write technology. By adapting half-toning techniques to the DMD bitmap image, the laser transfer threshold fluence for 10 μm features can be reduced using an edge-enhanced beam profile. The integration of LIFT with this beam-shaping technique allows the printing of complex large-area patterns with a single laser pulse.

[Investigation of fast filter of ECG signals with lifting wavelet and smooth filter].

PubMed

Li, Xuefei; Mao, Yuxing; He, Wei; Yang, Fan; Zhou, Liang

2008-02-01

The lifting wavelet is used to decompose the original ECG signals and separate them into the approach signals with low frequency and the detail signals with high frequency, based on frequency characteristic. Parts of the detail signals are ignored according to the frequency characteristic. To avoid the distortion of QRS Complexes, the approach signals are filtered by an adaptive smooth filter with a proper threshold value. Through the inverse transform of the lifting wavelet, the reserved approach signals are reconstructed, and the three primary kinds of noise are limited effectively. In addition, the method is fast and there is no time delay between input and output.

Study of Interpolated Timing Recovery Phase-Locked Loop with Linearly Constrained Adaptive Prefilter for Higher-Density Optical Disc

NASA Astrophysics Data System (ADS)

Kajiwara, Yoshiyuki; Shiraishi, Junya; Kobayashi, Shoei; Yamagami, Tamotsu

2009-03-01

A digital phase-locked loop (PLL) with a linearly constrained adaptive filter (LCAF) has been studied for higher-linear-density optical discs. LCAF has been implemented before an interpolated timing recovery (ITR) PLL unit in order to improve the quality of phase error calculation by using an adaptively equalized partial response (PR) signal. Coefficient update of an asynchronous sampled adaptive FIR filter with a least-mean-square (LMS) algorithm has been constrained by a projection matrix in order to suppress the phase shift of the tap coefficients of the adaptive filter. We have developed projection matrices that are suitable for Blu-ray disc (BD) drive systems by numerical simulation. Results have shown the properties of the projection matrices. Then, we have designed the read channel system of the ITR PLL with an LCAF model on the FPGA board for experiments. Results have shown that the LCAF improves the tilt margins of 30 gigabytes (GB) recordable BD (BD-R) and 33 GB BD read-only memory (BD-ROM) with a sufficient LMS adaptation stability.

Time-and-Spatially Adapting Simulations for Efficient Dynamic Stall Predictions

DTIC Science & Technology

2015-09-01

Experi- mental Investigation and Fundamental Understand- ing of a Full-Scale Slowed Rotor at High Advance Ratios,” Journal of the American Helicopter ...remains a major roadblock in the design and analysis of conventional rotors as well as new concepts for future vertical lift. Several approaches to...of conventional rotors as well as new concepts for future vertical lift. Several approaches to reduce the cost of these dynamic stall simulations for

Learned Manipulation at Unconstrained Contacts Does Not Transfer across Hands

PubMed Central

Fu, Qiushi; Choi, Jason Y.; Gordon, Andrew M.; Jesunathadas, Mark; Santello, Marco

2014-01-01

Recent studies about sensorimotor control of the human hand have focused on how dexterous manipulation is learned and generalized. Here we address this question by testing the extent to which learned manipulation can be transferred when the contralateral hand is used and/or object orientation is reversed. We asked subjects to use a precision grip to lift a grip device with an asymmetrical mass distribution while minimizing object roll during lifting by generating a compensatory torque. Subjects were allowed to grasp anywhere on the object’s vertical surfaces, and were therefore able to modulate both digit positions and forces. After every block of eight trials performed in one manipulation context (i.e., using the right hand and at a given object orientation), subjects had to lift the same object in the second context for one trial (transfer trial). Context changes were made by asking subjects to switch the hand used to lift the object and/or rotate the object 180° about a vertical axis. Therefore, three transfer conditions, hand switch (HS), object rotation (OR), and both hand switch and object rotation (HS+OR), were tested and compared with hand matched control groups who did not experience context changes. We found that subjects in all transfer conditions adapted digit positions across multiple transfer trials similar to the learning of control groups, regardless of different changes of contexts. Moreover, subjects in both HS and HS+OR group also adapted digit forces similar to the control group, suggesting independent learning of the left hand. In contrast, the OR group showed significant negative transfer of the compensatory torque due to an inability to adapt digit forces. Our results indicate that internal representations of dexterous manipulation tasks may be primarily built through the hand used for learning and cannot be transferred across hands. PMID:25233091

The physics of powerlifting

NASA Astrophysics Data System (ADS)

Radenković, Lazar; Nešić, Ljubiša

2018-05-01

The main contribution of this paper is didactic adaptation of the biomechanical analysis of the three main lifts in powerlifting (squat, bench press, deadlift). We used simple models that can easily be understood by undergraduate college students to estimate the values of various physical quantities during powerlifting. Specifically, we showed how plate choice affects the bench press and estimated spine loads and torques at hip and knee during lifting. Theoretical calculations showed good agreement with experimental data, proving that the models are valid.

Soft shape-adaptive gripping device made from artificial muscle

NASA Astrophysics Data System (ADS)

Hamburg, E.; Vunder, V.; Johanson, U.; Kaasik, F.; Aabloo, A.

2016-04-01

We report on a multifunctional four-finger gripper for soft robotics, suitable for performing delicate manipulation tasks. The gripping device is comprised of separately driven gripping and lifting mechanisms, both made from a separate single piece of smart material - ionic capacitive laminate (ICL) also known as artificial muscle. Compared to other similar devices the relatively high force output of the ICL material allows one to construct a device able to grab and lift objects exceeding multiple times its own weight. Due to flexible design of ICL grips, the device is able to adapt the complex shapes of different objects and allows grasping single or multiple objects simultaneously without damage. The performance of the gripper is evaluated in two different configurations: a) the ultimate grasping strength of the gripping hand; and b) the maximum lifting force of the lifting actuator. The ICL is composed of three main layers: a porous membrane consisting of non-ionic polymer poly(vinylidene fluoride-co-hexafluoropropene) (PVdF-HFP), ionic liquid 1-ethyl-3-methylimidazolium trifluoromethane-sulfonate (EMITFS), and a reinforcing layer of woven fiberglass cloth. Both sides of the membrane are coated with a carbonaceous electrode. The electrodes are additionally covered with thin gold layers, serving as current collectors. Device made of this material operates silently, requires low driving voltage (<3 V), and is suitable for performing tasks in open air environment.

Reversible wavelet filter banks with side informationless spatially adaptive low-pass filters

NASA Astrophysics Data System (ADS)

Abhayaratne, Charith

2011-07-01

Wavelet transforms that have an adaptive low-pass filter are useful in applications that require the signal singularities, sharp transitions, and image edges to be left intact in the low-pass signal. In scalable image coding, the spatial resolution scalability is achieved by reconstructing the low-pass signal subband, which corresponds to the desired resolution level, and discarding other high-frequency wavelet subbands. In such applications, it is vital to have low-pass subbands that are not affected by smoothing artifacts associated with low-pass filtering. We present the mathematical framework for achieving 1-D wavelet transforms that have a spatially adaptive low-pass filter (SALP) using the prediction-first lifting scheme. The adaptivity decisions are computed using the wavelet coefficients, and no bookkeeping is required for the perfect reconstruction. Then, 2-D wavelet transforms that have a spatially adaptive low-pass filter are designed by extending the 1-D SALP framework. Because the 2-D polyphase decompositions are used in this case, the 2-D adaptivity decisions are made nonseparable as opposed to the separable 2-D realization using 1-D transforms. We present examples using the 2-D 5/3 wavelet transform and their lossless image coding and scalable decoding performances in terms of quality and resolution scalability. The proposed 2-D-SALP scheme results in better performance compared to the existing adaptive update lifting schemes.

Volitional Weight-Lifting in Rats Promotes Adaptation via Performance and Muscle Morphology prior to Gains in Muscle Mass

PubMed Central

Rader, Erik P; Miller, G Roger; Chetlin, Robert D; Wirth, Oliver; Baker, Brent A

2014-01-01

Investigation of volitional animal models of resistance training has been instrumental in our understanding of adaptive training. However, these studies have lacked reactive force measurements, a precise performance measure, and morphological analysis at a distinct phase of training – when initial strength gains precede muscle hypertrophy. Our aim was to expose rats to one month of training (70 or 700 g load) on a custom-designed weight-lifting apparatus for analysis of reactive forces and muscle morphology prior to muscle hypertrophy. Exclusively following 700 g load training, forces increased by 21% whereas muscle masses remained unaltered. For soleus (SOL) and tibialis anterior (TA) muscles, 700 g load training increased muscle fiber number per unit area by ∼20% and decreased muscle fiber area by ∼20%. Additionally, number of muscle fibers per section increased by 18% for SOL muscles. These results establish that distinct morphological alterations accompany early strength gains in a volitional animal model of load-dependent adaptive resistance training. PMID:25392697

A comparison of flight and simulation data for three automatic landing system control laws for the Augmentor wing jet STOL research airplane

NASA Technical Reports Server (NTRS)

Feinreich, B.; Gevaert, G.

1980-01-01

Automatic flare and decrab control laws for conventional takeoff and landing aircraft were adapted to the unique requirements of the powered lift short takeoff and landing airplane. Three longitudinal autoland control laws were developed. Direct lift and direct drag control were used in the longitudinal axis. A fast time simulation was used for the control law synthesis, with emphasis on stochastic performance prediction and evaluation. Good correlation with flight test results was obtained.

Adaptive Constrained Optimal Control Design for Data-Based Nonlinear Discrete-Time Systems With Critic-Only Structure.

PubMed

Luo, Biao; Liu, Derong; Wu, Huai-Ning

2018-06-01

Reinforcement learning has proved to be a powerful tool to solve optimal control problems over the past few years. However, the data-based constrained optimal control problem of nonaffine nonlinear discrete-time systems has rarely been studied yet. To solve this problem, an adaptive optimal control approach is developed by using the value iteration-based Q-learning (VIQL) with the critic-only structure. Most of the existing constrained control methods require the use of a certain performance index and only suit for linear or affine nonlinear systems, which is unreasonable in practice. To overcome this problem, the system transformation is first introduced with the general performance index. Then, the constrained optimal control problem is converted to an unconstrained optimal control problem. By introducing the action-state value function, i.e., Q-function, the VIQL algorithm is proposed to learn the optimal Q-function of the data-based unconstrained optimal control problem. The convergence results of the VIQL algorithm are established with an easy-to-realize initial condition . To implement the VIQL algorithm, the critic-only structure is developed, where only one neural network is required to approximate the Q-function. The converged Q-function obtained from the critic-only VIQL method is employed to design the adaptive constrained optimal controller based on the gradient descent scheme. Finally, the effectiveness of the developed adaptive control method is tested on three examples with computer simulation.

Parametric study of a canard-configured transport using conceptual design optimization

NASA Technical Reports Server (NTRS)

Arbuckle, P. D.; Sliwa, S. M.

1985-01-01

Constrained-parameter optimization is used to perform optimal conceptual design of both canard and conventional configurations of a medium-range transport. A number of design constants and design constraints are systematically varied to compare the sensitivities of canard and conventional configurations to a variety of technology assumptions. Main-landing-gear location and canard surface high-lift performance are identified as critical design parameters for a statically stable, subsonic, canard-configured transport.

Adaptive Driving Equipment: Selection and Major Considerations [and] Battery Powered Scooters and 3-Wheelers. Information Support Packets #1 and #2.

ERIC Educational Resources Information Center

Stevens, John H.

Two brief guides offer suggestions for persons with physical disabilities who are considering the purchase of adaptive driving equipment, battery-powered scooters, or three wheelers. The first guide offers guidelines for individuals considering purchase of special hand controls or other modifications or a van lift to enhance their independence in…

A Quasi-Steady Lifting Line Theory for Insect-Like Hovering Flight

PubMed Central

Nabawy, Mostafa R. A.; Crowthe, William J.

2015-01-01

A novel lifting line formulation is presented for the quasi-steady aerodynamic evaluation of insect-like wings in hovering flight. The approach allows accurate estimation of aerodynamic forces from geometry and kinematic information alone and provides for the first time quantitative information on the relative contribution of induced and profile drag associated with lift production for insect-like wings in hover. The main adaptation to the existing lifting line theory is the use of an equivalent angle of attack, which enables capture of the steady non-linear aerodynamics at high angles of attack. A simple methodology to include non-ideal induced effects due to wake periodicity and effective actuator disc area within the lifting line theory is included in the model. Low Reynolds number effects as well as the edge velocity correction required to account for different wing planform shapes are incorporated through appropriate modification of the wing section lift curve slope. The model has been successfully validated against measurements from revolving wing experiments and high order computational fluid dynamics simulations. Model predicted mean lift to weight ratio results have an average error of 4% compared to values from computational fluid dynamics for eight different insect cases. Application of an unmodified linear lifting line approach leads on average to a 60% overestimation in the mean lift force required for weight support, with most of the discrepancy due to use of linear aerodynamics. It is shown that on average for the eight insects considered, the induced drag contributes 22% of the total drag based on the mean cycle values and 29% of the total drag based on the mid half-stroke values. PMID:26252657

Going Boldly Beyond: Progress on NASA's Space Launch System

NASA Technical Reports Server (NTRS)

Singer, Jody; Crumbly, Chris

2013-01-01

NASA's Space Launch System is implementing an evolvable configuration approach to system development in a resource-constrained era. Legacy systems enable non-traditional development funding and contribute to sustainability and affordability. Limited simultaneous developments reduce cost and schedule risk. Phased approach to advanced booster development enables innovation and competition, incrementally demonstrating affordability and performance enhancements. Advanced boosters will provide performance for the most capable heavy lift launcher in history, enabling unprecedented space exploration benefiting all of humanity.

Aeroelasticity of morphing wings using neural networks

NASA Astrophysics Data System (ADS)

Natarajan, Anand

In this dissertation, neural networks are designed to effectively model static non-linear aeroelastic problems in adaptive structures and linear dynamic aeroelastic systems with time varying stiffness. The use of adaptive materials in aircraft wings allows for the change of the contour or the configuration of a wing (morphing) in flight. The use of smart materials, to accomplish these deformations, can imply that the stiffness of the wing with a morphing contour changes as the contour changes. For a rapidly oscillating body in a fluid field, continuously adapting structural parameters may render the wing to behave as a time variant system. Even the internal spars/ribs of the aircraft wing which define the wing stiffness can be made adaptive, that is, their stiffness can be made to vary with time. The immediate effect on the structural dynamics of the wing, is that, the wing motion is governed by a differential equation with time varying coefficients. The study of this concept of a time varying torsional stiffness, made possible by the use of active materials and adaptive spars, in the dynamic aeroelastic behavior of an adaptable airfoil is performed here. Another type of aeroelastic problem of an adaptive structure that is investigated here, is the shape control of an adaptive bump situated on the leading edge of an airfoil. Such a bump is useful in achieving flow separation control for lateral directional maneuverability of the aircraft. Since actuators are being used to create this bump on the wing surface, the energy required to do so needs to be minimized. The adverse pressure drag as a result of this bump needs to be controlled so that the loss in lift over the wing is made minimal. The design of such a "spoiler bump" on the surface of the airfoil is an optimization problem of maximizing pressure drag due to flow separation while minimizing the loss in lift and energy required to deform the bump. One neural network is trained using the CFD code FLUENT to represent the aerodynamic loading over the bump. A second neural network is trained for calculating the actuator loads, bump displacement and lift, drag forces over the airfoil using the finite element solver, ANSYS and the previously trained neural network. This non-linear aeroelastic model of the deforming bump on an airfoil surface using neural networks can serve as a fore-runner for other non-linear aeroelastic problems.

Feasibility Analysis and Evaluation of an Adaptive Tracked Vehicle Suspension and Control System

DTIC Science & Technology

1975-06-01

CONTROL SYSTEM FINAL REPORT JUNE 1975 Contract No. DAAE07-72-C-017 D D C •W 6 1976 B t> y Robert M. Salemka National Water Lift Company A...spring rate which is as soft as a hydropneumatic system. 3.3 Adaptive Control The adaptive control was achieved by switching the jounce damping relief...inherently included in this type of system. The solenoid valves are of the normally closed type so that with no electrical power , the system will

Application of an optimized winglet configuration to an advanced commercial transport

NASA Technical Reports Server (NTRS)

Shollenberger, C. A.

1979-01-01

The design is presented of an aircraft which employs an integrated wing and winglet lift system. Comparison was made with a conventional baseline configuration employing a high-aspect-ratio supercritical wing. An optimized wing-winglet combination was selected from four proposed configurations for which aerodynamic, structural, and weight characteristics were evaluated. Each candidate wing-winglet configuration was constrained to the same induced drag coefficient as the baseline aircraft. The selected wing-winglet configuration was resized for a specific medium-range mission requirement, and operating costs were estimated for a typical mission. Study results indicated that the wing-winglet aircraft was lighter and could complete the specified mission at less cost than the conventional wing aircraft. These indications were sensitive to the impact of flutter characteristics and, to a lesser extent, to the performance of the high-lift system. Further study in these areas is recommended to reduce uncertainty in future development.

Grip force regulation during pinch grip lifts under somatosensory guidance: comparison between people with stroke and healthy controls.

PubMed

Blennerhassett, Jannette M; Carey, Leeanne M; Matyas, Thomas A

2006-03-01

To compare the timing and grip force application in a pinch grip task performed under somatosensory guidance in stroke and matched controls and to identify characteristics of impaired grip force regulation after stroke. Matched-pairs control group. University research laboratory. Forty-five people with stroke who could pick up a pen lid using a pinch grip and actively participated in rehabilitation and 45 adults without neurologic conditions or musculoskeletal or skin impairments affecting the hand, matched for age, sex, and hand dominance. Not applicable. Timing and magnitude of grip forces applied during pinch grip lift and hold. Prolonged time to grip and lift objects, and excessive grip force prior to commencing the lift occurred in approximately half of the contralesional (involved) hands of people with stroke. Fluctuating irregular forces and reduced adaptation of the grip safety margin were also observed. Excessive safety margins were not predominant after stroke. Extreme slowing and disorganized sequencing of the grip and lifting forces and difficulty maintaining a stable grip characterized severe dysfunction. Delayed grip formulation and variable grip force application are key characteristics of grip dysfunction after stroke.

Enhancing multi-step quantum state tomography by PhaseLift

NASA Astrophysics Data System (ADS)

Lu, Yiping; Zhao, Qing

2017-09-01

Multi-photon system has been studied by many groups, however the biggest challenge faced is the number of copies of an unknown state are limited and far from detecting quantum entanglement. The difficulty to prepare copies of the state is even more serious for the quantum state tomography. One possible way to solve this problem is to use adaptive quantum state tomography, which means to get a preliminary density matrix in the first step and revise it in the second step. In order to improve the performance of adaptive quantum state tomography, we develop a new distribution scheme of samples and extend it to three steps, that is to correct it once again based on the density matrix obtained in the traditional adaptive quantum state tomography. Our numerical results show that the mean square error of the reconstructed density matrix by our new method is improved to the level from 10-4 to 10-9 for several tested states. In addition, PhaseLift is also applied to reduce the required storage space of measurement operator.

A novel rail defect detection method based on undecimated lifting wavelet packet transform and Shannon entropy-improved adaptive line enhancer

NASA Astrophysics Data System (ADS)

Hao, Qiushi; Zhang, Xin; Wang, Yan; Shen, Yi; Makis, Viliam

2018-07-01

Acoustic emission (AE) technology is sensitive to subliminal rail defects, however strong wheel-rail contact rolling noise under high-speed condition has gravely impeded detecting of rail defects using traditional denoising methods. In this context, the paper develops an adaptive detection method for rail cracks, which combines multiresolution analysis with an improved adaptive line enhancer (ALE). To obtain elaborate multiresolution information of transient crack signals with low computational cost, lifting scheme-based undecimated wavelet packet transform is adopted. In order to feature the impulsive property of crack signals, a Shannon entropy-improved ALE is proposed as a signal enhancing approach, where Shannon entropy is introduced to improve the cost function. Then a rail defect detection plan based on the proposed method for high-speed condition is put forward. From theoretical analysis and experimental verification, it is demonstrated that the proposed method has superior performance in enhancing the rail defect AE signal and reducing the strong background noise, offering an effective multiresolution approach for rail defect detection under high-speed and strong-noise condition.

Performance evaluation of the atmospheric phase of aeromaneuvering orbital transfer vehicles

NASA Technical Reports Server (NTRS)

Powell, R. W.; Stone, H. W.; Naftel, J. C.

1984-01-01

Studies are underway to design reusable orbital transfer vehicles that would be used to transfer payloads from low-earth orbit to higher orbits and return. One promising concept is to use an atmospheric pass on the return leg to reduce the amount of fuel for the mission. This paper discusses a six-degree-of-freedom simulation analysis for two configurations, a low-lift-to-drag ratio configuration and a medium-lift-to-drag ratio configuration using both a predictive guidance technique and an adaptive guidance technique. Both guidance schemes were evaluated using the 1962 standard atmosphere and three atmospheres that had been derived from three entries of the Space Shuttle. The predictive technique requires less reaction control system activity for both configurations, but because of the limited number of updates and because each update used the 1962 standard atmosphere, the adaptive technique produces more accurate exit conditions.

Advances in Highly Constrained Multi-Phase Trajectory Generation using the General Pseudospectral Optimization Software (GPOPS)

DTIC Science & Technology

2013-08-01

release; distribution unlimited. PA Number 412-TW-PA-13395 f generic function g acceleration due to gravity h altitude L aerodynamic lift force L Lagrange...cost m vehicle mass M Mach number n number of coefficients in polynomial regression p highest order of polynomial regression Q dynamic pressure R...Method (RPM); the collocation points are defined by the roots of Legendre -Gauss- Radau (LGR) functions.9 GPOPS also automatically refines the “mesh” by

A Numerical Method for Calculating the Wave Drag of a Configuration from the Second Derivative of the Area Distribution of a Series of Equivalent Bodies of Revolution

NASA Technical Reports Server (NTRS)

Levy, Lionel L., Jr.; Yoshikawa, Kenneth K.

1959-01-01

A method based on linearized and slender-body theories, which is easily adapted to electronic-machine computing equipment, is developed for calculating the zero-lift wave drag of single- and multiple-component configurations from a knowledge of the second derivative of the area distribution of a series of equivalent bodies of revolution. The accuracy and computational time required of the method to calculate zero-lift wave drag is evaluated relative to another numerical method which employs the Tchebichef form of harmonic analysis of the area distribution of a series of equivalent bodies of revolution. The results of the evaluation indicate that the total zero-lift wave drag of a multiple-component configuration can generally be calculated most accurately as the sum of the zero-lift wave drag of each component alone plus the zero-lift interference wave drag between all pairs of components. The accuracy and computational time required of both methods to calculate total zero-lift wave drag at supersonic Mach numbers is comparable for airplane-type configurations. For systems of bodies of revolution both methods yield similar results with comparable accuracy; however, the present method only requires up to 60 percent of the computing time required of the harmonic-analysis method for two bodies of revolution and less time for a larger number of bodies.

Linking actions and objects: Context-specific learning of novel weight priors.

PubMed

Trewartha, Kevin M; Flanagan, J Randall

2017-06-01

Distinct explicit and implicit memory processes support weight predictions used when lifting objects and making perceptual judgments about weight, respectively. The first time that an object is encountered weight is predicted on the basis of learned associations, or priors, linking size and material to weight. A fundamental question is whether the brain maintains a single, global representation of priors, or multiple representations that can be updated in a context specific way. A second key question is whether the updating of priors, or the ability to scale lifting forces when repeatedly lifting unusually weighted objects requires focused attention. To investigate these questions we compared the adaptability of weight predictions used when lifting objects and judging their weights in different groups of participants who experienced size-weight inverted objects passively (with the objects placed on the hands) or actively (where participants lift the objects) under full or divided attention. To assess weight judgments we measured the size-weight illusion after every 20 trials of experience with the inverted objects both passively and actively. The attenuation of the illusion that arises when lifting inverted object was found to be context-specific such that the attenuation was larger when the mode of interaction with the inverted objects matched the method of assessment of the illusion. Dividing attention during interaction with the inverted objects had no effect on attenuation of the illusion, but did slow the rate at which lifting forces were scaled to the weight inverted objects. These findings suggest that the brain stores multiple representations of priors that are context specific, and that focused attention is important for scaling lifting forces, but not for updating weight predictions used when judging object weight. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparison of conventional and adaptive wall wind tunnel results with regard to Reynolds number effects

NASA Technical Reports Server (NTRS)

Stanewsky, E.; Freimuth, P.

1989-01-01

A comparison of results from conventional and adaptive wall wind tunnels with regard to Reynolds number effects was carried out. The special objective of this comparison was to confirm or reject earlier conclusions, soley based on conventional wind tunnel results, concerning the influence of viscous effects on the characteristics of partially open wind tunnel walls, hence wall interference. The following postulations could be confirmed: (1) certain classes of supercritical airfoils exhibit a non-linear increase in lift which is, at least in part, related to viscous-inviscid interactions on the airfoil. This non-linear lift characteristic can erroneously be suppressed by sidewall interference effects in addition to being affected by changes in Reynolds number. Adaptive walls seem to relieve the influence of sidewall interference; (2) the degree of (horizontal) wall interference effects can be significantly affected by changes in Reynolds number, thus appearing as true Reynolds number effects; (3) perforated wall characteristics seem much more susceptible to viscous changes than the characteristics of slotted walls; here, blockage interference may be most severely influenced by viscous changes; and (4) real Reynolds number effects are present on the CAST 10-2/DOA 2 airfoil; they were shown to be appreciable also by the adaptive wall wind tunnel tests.

An International Symposium and Exhibition on Active Materials and Adaptive Structures.

DTIC Science & Technology

1991-11-08

into Tubular Composite Structures Using Embedded Constraining Layers 232 S. Sattinger, Z. Sanjana, Westinghouse Science and Technology Center...struts, constrained layers , and tuned mass dampers. The most effective damping treatment was selected for each mode depending on its modal...paper) the passive damping component* in the structure will be deserth^ These »dude constrained layer viscoelastic struts« viscous DStrlJi . .^ of

Convergence behavior that controls adaptive wind tunnel walls near the test section in the high angle of attack range

NASA Technical Reports Server (NTRS)

Ziemann, J.

1982-01-01

The NACA 0012 profile at Mach 0.5 was investigated in a wind tunnel with adaptive walls. It is found that adaptation of the flexible walls is possible in the high angle of attack range on both sides of maximum lift. Oil film photographs of the flow at the profile surface show three dimensional effects in the region of the corners between the profile and the sidewall. It is concluded that pure two dimensional separated flow is not possible.

Propulsion system mathematical model for a lift/cruise fan V/STOL aircraft

NASA Technical Reports Server (NTRS)

Cole, G. L.; Sellers, J. F.; Tinling, B. E.

1980-01-01

A propulsion system mathematical model is documented that allows calculation of internal engine parameters during transient operation. A non-realtime digital computer simulation of the model is presented. It is used to investigate thrust response and modulation requirements as well as the impact of duty cycle on engine life and design criteria. Comparison of simulation results with steady-state cycle deck calculations showed good agreement. The model was developed for a specific 3-fan subsonic V/STOL aircraft application, but it can be adapted for use with any similar lift/cruise V/STOL configuration.

Longitudinal aerodynamic performance of a series of power-law and minimum wave drag bodies at Mach 6 and several Reynolds numbers

NASA Technical Reports Server (NTRS)

Ashby, G. C., Jr.

1974-01-01

Experimental data have been obtained for two series of bodies at Mach 6 and Reynolds numbers, based on model length, from 1.4 million to 9.5 million. One series consisted of axisymmetric power-law bodies geometrically constrained for constant length and base diameter with values of the exponent n of 0.25, 0.5, 0.6, 0.667, 0.75, and 1.0. The other series consisted of positively and negatively cambered bodies of polygonal cross section, each having a constant longitudinal area distribution conforming to that required for minimizing zero-lift wave drag at hypersonic speeds under the geometric constraints of given length and volume. At the highest Reynolds number, the power-law body for minimum drag is blunter (exponent n lower) than predicted by inviscid theory (n approximately 0.6 instead of n = 0.667); however, the peak value of lift-drag ratio occurs at n = 0.667. Viscous effects were present on the bodies of polygonal cross section but were less pronounced than those on the power-law bodies. The trapezoidal bodies with maximum width at the bottom were found to have the highest maximum lift-drag ratio and the lowest mimimum drag.

Genes under weaker stabilizing selection increase network evolvability and rapid regulatory adaptation to an environmental shift.

PubMed

Laarits, T; Bordalo, P; Lemos, B

2016-08-01

Regulatory networks play a central role in the modulation of gene expression, the control of cellular differentiation, and the emergence of complex phenotypes. Regulatory networks could constrain or facilitate evolutionary adaptation in gene expression levels. Here, we model the adaptation of regulatory networks and gene expression levels to a shift in the environment that alters the optimal expression level of a single gene. Our analyses show signatures of natural selection on regulatory networks that both constrain and facilitate rapid evolution of gene expression level towards new optima. The analyses are interpreted from the standpoint of neutral expectations and illustrate the challenge to making inferences about network adaptation. Furthermore, we examine the consequence of variable stabilizing selection across genes on the strength and direction of interactions in regulatory networks and in their subsequent adaptation. We observe that directional selection on a highly constrained gene previously under strong stabilizing selection was more efficient when the gene was embedded within a network of partners under relaxed stabilizing selection pressure. The observation leads to the expectation that evolutionarily resilient regulatory networks will contain optimal ratios of genes whose expression is under weak and strong stabilizing selection. Altogether, our results suggest that the variable strengths of stabilizing selection across genes within regulatory networks might itself contribute to the long-term adaptation of complex phenotypes. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

Longitudinal Aerodynamic Modeling of the Adaptive Compliant Trailing Edge Flaps on a GIII Airplane and Comparisons to Flight Data

NASA Technical Reports Server (NTRS)

Smith, Mark S.; Bui, Trong T.; Garcia, Christian A.; Cumming, Stephen B.

2016-01-01

A pair of compliant trailing edge flaps was flown on a modified GIII airplane. Prior to flight test, multiple analysis tools of various levels of complexity were used to predict the aerodynamic effects of the flaps. Vortex lattice, full potential flow, and full Navier-Stokes aerodynamic analysis software programs were used for prediction, in addition to another program that used empirical data. After the flight-test series, lift and pitching moment coefficient increments due to the flaps were estimated from flight data and compared to the results of the predictive tools. The predicted lift increments matched flight data well for all predictive tools for small flap deflections. All tools over-predicted lift increments for large flap deflections. The potential flow and Navier-Stokes programs predicted pitching moment coefficient increments better than the other tools.

Ultrastable Photoelectrodes for Solar Water Splitting Based on Organic Metal Halide Perovskite Fabricated by Lift-Off Process.

PubMed

Nam, SeongSik; Mai, Cuc Thi Kim; Oh, Ilwhan

2018-05-02

Herein, we report an integrated photoelectrolysis of water employing organic metal halide (OMH) perovskite material. As generic OMH perovskite material and device architecture are highly susceptible to degradation by aqueous electrolytes, we have developed a versatile mold-cast and lift-off process to fabricate and assemble multipurpose metal encapsulation onto perovskite devices. With the metal encapsulation effectively protecting the perovskite cell and also functioning as electrocatalyst, the high-performance perovskite photoelectrodes exhibit high photovoltage and photocurrent that are effectively inherited from the original solid-state solar cell. More importantly, thus-fabricated perovskite photoelectrode demonstrates record-long unprecedented stability even at highly oxidizing potential in strong alkaline electrolyte. We expect that this versatile lift-off process can be adapted in a wide variety of photoelectrochemical devices to protect the material surfaces from corroding electrolyte and facilitate various electrochemical reactions.

The Compton-thick Growth of Supermassive Black Holes constrained

NASA Astrophysics Data System (ADS)

Buchner, Johannes; Georgakakis, Antonis; Nandra, Kirpal; Brightman, Murray; Menzel, Marie-Luise; Liu, Zhu; Hsu, Li-Ting; Salvato, Mara; Rangel, Cyprian; Aird, James

2017-08-01

A heavily obscured growth phase of supermassive black holes (SMBH) is thought to be important in the co-evolution with galaxies. X-rays provide a clean and efficient selection of unobscured and obscured AGN. Recent work with deeper observations and improved analysis methodology allowed us to extend constraints to Compton-thick number densities. We present the first luminosity function of Compton-thick AGN at z=0.5-4 and constrain the overall mass density locked into black holes over cosmic time, a fundamental constraint for cosmological simulations. Recent studies including ours find that the obscuration is redshift and luminosity-dependent in a complex way, which rules out entire sets of obscurer models. A new paradigm, the radiation-lifted torus model, is proposed, in which the obscurer is Eddington-rate dependent and accretion creates and displaces torus clouds. We place observational limits on the behaviour of this mechanism.

The Compton-thick Growth of Supermassive Black Holes constrained

NASA Astrophysics Data System (ADS)

Buchner, J.; Georgakakis, A.; Nandra, K.

2017-10-01

A heavily obscured growth phase of supermassive black holes (SMBH) is thought to be important in the co-evolution with galaxies. X-rays provide a clean and efficient selection of unobscured and obscured AGN. Recent work with deeper observations and improved analysis methodology allowed us to extend constraints to Compton-thick number densities. We present the first luminosity function of Compton-thick AGN at z=0.5-4 and constrain the overall mass density locked into black holes over cosmic time, a fundamental constraint for cosmological simulations. Recent studies including ours find that the obscuration is redshift and luminosity-dependent in a complex way, which rules out entire sets of obscurer models. A new paradigm, the radiation-lifted torus model, is proposed, in which the obscurer is Eddington-rate dependent and accretion creates and displaces torus clouds. We place observational limits on the behaviour of this mechanism.

An approach to constrained aerodynamic design with application to airfoils

NASA Technical Reports Server (NTRS)

Campbell, Richard L.

1992-01-01

An approach was developed for incorporating flow and geometric constraints into the Direct Iterative Surface Curvature (DISC) design method. In this approach, an initial target pressure distribution is developed using a set of control points. The chordwise locations and pressure levels of these points are initially estimated either from empirical relationships and observed characteristics of pressure distributions for a given class of airfoils or by fitting the points to an existing pressure distribution. These values are then automatically adjusted during the design process to satisfy the flow and geometric constraints. The flow constraints currently available are lift, wave drag, pitching moment, pressure gradient, and local pressure levels. The geometric constraint options include maximum thickness, local thickness, leading-edge radius, and a 'glove' constraint involving inner and outer bounding surfaces. This design method was also extended to include the successive constraint release (SCR) approach to constrained minimization.

Fast-adapting mechanoreceptors are important for force control in precision grip but not for sensorimotor memory.

PubMed

Park, Susanna B; Davare, Marco; Falla, Marika; Kennedy, William R; Selim, Mona M; Wendelschafer-Crabb, Gwen; Koltzenburg, Martin

2016-06-01

Sensory feedback from cutaneous mechanoreceptors in the fingertips is important in effective object manipulation, allowing appropriate scaling of grip and load forces during precision grip. However, the role of mechanoreceptor subtypes in these tasks remains incompletely understood. To address this issue, psychophysical tasks that may specifically assess function of type I fast-adapting (FAI) and slowly adapting (SAI) mechanoreceptors were used with object manipulation experiments to examine the regulation of grip force control in an experimental model of graded reduction in tactile sensitivity (healthy volunteers wearing 2 layers of latex gloves). With gloves, tactile sensitivity decreased significantly from 1.9 ± 0.4 to 12.3 ± 2.2 μm in the Bumps task assessing function of FAI afferents but not in a grating orientation task assessing SAI afferents (1.6 ± 0.1 to 1.8 ± 0.2 mm). Six axis force/torque sensors measured peak grip (PGF) and load (PLF) forces generated by the fingertips during a grip-lift task. With gloves there was a significant increase of PGF (14 ± 6%), PLF (17 ± 5%), and grip and load force rates (26 ± 8%, 20 ± 8%). A variable-weight series task was used to examine sensorimotor memory. There was a 20% increase in PGF when the lift of a light object was preceded by a heavy relative to a light object. This relationship was not significantly altered when lifting with gloves, suggesting that the addition of gloves did not change sensorimotor memory effects. We conclude that FAI fibers may be important for the online force scaling but not for the buildup of a sensorimotor memory. Copyright © 2016 the American Physiological Society.

Simple models for rope substructure mechanics: application to electro-mechanical lifts

NASA Astrophysics Data System (ADS)

Herrera, I.; Kaczmarczyk, S.

2016-05-01

Mechanical systems modelled as rigid mass elements connected by tensioned slender structural members such as ropes and cables represent quite common substructures used in lift engineering and hoisting applications. Special interest is devoted by engineers and researchers to the vibratory response of such systems for optimum performance and durability. This paper presents simplified models that can be employed to determine the natural frequencies of systems having substructures of two rigid masses constrained by tensioned rope/cable elements. The exact solution for free un-damped longitudinal displacement response is discussed in the context of simple two-degree-of-freedom models. The results are compared and the influence of characteristics parameters such as the ratio of the average mass of the two rigid masses with respect to the rope mass and the deviation ratio of the two rigid masses with respect to the average mass is analyzed. This analysis gives criteria for the application of such simplified models in complex elevator and hoisting system configurations.

Artificial Bird Feathers: An Adaptive Wing with High Lift Capability.

NASA Astrophysics Data System (ADS)

Hage, W.; Meyer, R.; Bechert, D. W.

1997-11-01

In Wind tunnel experiments, the operation of the covering feathers of bird wings has been investigated. At incipient flow separation, local flow reversal lifts the feathers and inhibits the spreading of the separation regime towards the leading edge. This mechanism can be utilized by movable flaps on airfoils. The operation of quasi-steady and of vibrating movable flaps is outlined. These devices are self-actuated, require no energy and do not produce parasitic drag. They are compatible with laminar and turbulent airfoils as well as with various conventional flaps on aircraft wings. Laboratory and flight experiments are shown. Ref: AIAA-Paper 97-1960.

Voltera's Solution of the Wave Equation as Applied to Three-Dimensional Supersonic Airfoil Problems

NASA Technical Reports Server (NTRS)

Heslet, Max A; Lomax, Harvard; Jones, Arthur L

1947-01-01

A surface integral is developed which yields solutions of the linearized partial differential equation for supersonic flow. These solutions satisfy boundary conditions arising in wing theory. Particular applications of this general method are made, using acceleration potentials, to flat surfaces and to uniformly loaded lifting surfaces. Rectangular and trapezoidal plan forms are considered along with triangular forms adaptable to swept-forward and swept-back wings. The case of the triangular plan form in sideslip is also included. Emphasis is placed on the systematic application of the method to the lifting surfaces considered and on the possibility of further application.

Constrained tri-sphere kinematic positioning system

DOEpatents

Viola, Robert J

2010-12-14

A scalable and adaptable, six-degree-of-freedom, kinematic positioning system is described. The system can position objects supported on top of, or suspended from, jacks comprising constrained joints. The system is compatible with extreme low temperature or high vacuum environments. When constant adjustment is not required a removable motor unit is available.

Robust LS-SVM-based adaptive constrained control for a class of uncertain nonlinear systems with time-varying predefined performance

NASA Astrophysics Data System (ADS)

Luo, Jianjun; Wei, Caisheng; Dai, Honghua; Yuan, Jianping

2018-03-01

This paper focuses on robust adaptive control for a class of uncertain nonlinear systems subject to input saturation and external disturbance with guaranteed predefined tracking performance. To reduce the limitations of classical predefined performance control method in the presence of unknown initial tracking errors, a novel predefined performance function with time-varying design parameters is first proposed. Then, aiming at reducing the complexity of nonlinear approximations, only two least-square-support-vector-machine-based (LS-SVM-based) approximators with two design parameters are required through norm form transformation of the original system. Further, a novel LS-SVM-based adaptive constrained control scheme is developed under the time-vary predefined performance using backstepping technique. Wherein, to avoid the tedious analysis and repeated differentiations of virtual control laws in the backstepping technique, a simple and robust finite-time-convergent differentiator is devised to only extract its first-order derivative at each step in the presence of external disturbance. In this sense, the inherent demerit of backstepping technique-;explosion of terms; brought by the recursive virtual controller design is conquered. Moreover, an auxiliary system is designed to compensate the control saturation. Finally, three groups of numerical simulations are employed to validate the effectiveness of the newly developed differentiator and the proposed adaptive constrained control scheme.

Growing Organic Crystals By The Czochralski Method

NASA Technical Reports Server (NTRS)

Shields, Angela; Frazier, Donald O.; Penn, Benjamin G.; Aggarwal, M. D.; Wang, W. S.

1994-01-01

Apparatus grows high-quality single crystals of organic compounds by Czochralski method. In Czochralski process, growing crystal lifted from middle of molten material without touching walls. Because of low melting temperatures of organic crystals, glass vessels usable. Traditional method for inorganic semiconductors adapted to optically nonlinear organic materials.

Predictions of Transient Flame Lift-Off Length With Comparison to Single-Cylinder Optical Engine Experiments

DOE PAGES

Senecal, P. K.; Pomraning, E.; Anders, J. W.; ...

2014-05-28

A state-of-the-art, grid-convergent simulation methodology was applied to three-dimensional calculations of a single-cylinder optical engine. A mesh resolution study on a sector-based version of the engine geometry further verified the RANS-based cell size recommendations previously presented by Senecal et al. (“Grid Convergent Spray Models for Internal Combustion Engine CFD Simulations,” ASME Paper No. ICEF2012-92043). Convergence of cylinder pressure, flame lift-off length, and emissions was achieved for an adaptive mesh refinement cell size of 0.35 mm. Furthermore, full geometry simulations, using mesh settings derived from the grid convergence study, resulted in excellent agreement with measurements of cylinder pressure, heat release rate,more » and NOx emissions. On the other hand, the full geometry simulations indicated that the flame lift-off length is not converged at 0.35 mm for jets not aligned with the computational mesh. Further simulations suggested that the flame lift-off lengths for both the nonaligned and aligned jets appear to be converged at 0.175 mm. With this increased mesh resolution, both the trends and magnitudes in flame lift-off length were well predicted with the current simulation methodology. Good agreement between the overall predicted flame behavior and the available chemiluminescence measurements was also achieved. Our present study indicates that cell size requirements for accurate prediction of full geometry flame lift-off lengths may be stricter than those for global combustion behavior. This may be important when accurate soot predictions are required.« less

Predictions of Transient Flame Lift-Off Length With Comparison to Single-Cylinder Optical Engine Experiments

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

Senecal, P. K.; Pomraning, E.; Anders, J. W.

A state-of-the-art, grid-convergent simulation methodology was applied to three-dimensional calculations of a single-cylinder optical engine. A mesh resolution study on a sector-based version of the engine geometry further verified the RANS-based cell size recommendations previously presented by Senecal et al. (“Grid Convergent Spray Models for Internal Combustion Engine CFD Simulations,” ASME Paper No. ICEF2012-92043). Convergence of cylinder pressure, flame lift-off length, and emissions was achieved for an adaptive mesh refinement cell size of 0.35 mm. Furthermore, full geometry simulations, using mesh settings derived from the grid convergence study, resulted in excellent agreement with measurements of cylinder pressure, heat release rate,more » and NOx emissions. On the other hand, the full geometry simulations indicated that the flame lift-off length is not converged at 0.35 mm for jets not aligned with the computational mesh. Further simulations suggested that the flame lift-off lengths for both the nonaligned and aligned jets appear to be converged at 0.175 mm. With this increased mesh resolution, both the trends and magnitudes in flame lift-off length were well predicted with the current simulation methodology. Good agreement between the overall predicted flame behavior and the available chemiluminescence measurements was also achieved. Our present study indicates that cell size requirements for accurate prediction of full geometry flame lift-off lengths may be stricter than those for global combustion behavior. This may be important when accurate soot predictions are required.« less

Lift Optimization Study of a Multi-Element Three-Segment Variable Camber Airfoil

NASA Technical Reports Server (NTRS)

Kaul, Upender K.; Nguyen, Nhan T.

2016-01-01

This paper reports a detailed computational high-lift study of the Variable Camber Continuous Trailing Edge Flap (VCCTEF) system carried out to explore the best VCCTEF designs, in conjunction with a leading edge flap called the Variable Camber Krueger (VCK), for take-off and landing. For this purpose, a three-segment variable camber airfoil employed as a performance adaptive aeroelastic wing shaping control effector for a NASA Generic Transport Model (GTM) in landing and take-off configurations is considered. The objective of the study is to define optimal high-lift VCCTEF settings and VCK settings/configurations. A total of 224 combinations of VCK settings/configurations and VCCTEF settings are considered for the inboard GTM wing, where the VCCTEFs are configured as a Fowler flap that forms a slot between the VCCTEF and the main wing. For the VCK settings of deflection angles of 55deg, 60deg and 65deg, 18, 19 and 19 vck configurations, respectively, were considered for each of the 4 different VCCTEF deflection settings. Different vck configurations were defined by varying the horizontal and vertical distance of the vck from the main wing. A computational investigation using a Reynolds-Averaged Navier-Stokes (RANS) solver was carried out to complement a wind-tunnel experimental study covering three of these configurations with the goal of identifying the most optimal high-lift configurations. Four most optimal high-lift configurations, corresponding to each of the VCK deflection settings, have been identified out of all the different configurations considered in this study yielding the highest lift performance.

Anticipatory planning and control of grasp positions and forces for dexterous two-digit manipulation.

PubMed

Fu, Qiushi; Zhang, Wei; Santello, Marco

2010-07-07

Dexterous object manipulation requires anticipatory control of digit positions and forces. Despite extensive studies on sensorimotor learning of digit forces, how humans learn to coordinate digit positions and forces has never been addressed. Furthermore, the functional role of anticipatory modulation of digit placement to object properties remains to be investigated. We addressed these questions by asking human subjects (12 females, 12 males) to grasp and lift an inverted T-shaped object using precision grip at constrained or self-chosen locations. The task requirement was to minimize object roll during lift. When digit position was not constrained, subjects could have implemented many equally valid digit position-force coordination patterns. However, choice of digit placement might also have resulted in large trial-to-trial variability of digit position, hence challenging the extent to which the CNS could have relied on sensorimotor memories for anticipatory control of digit forces. We hypothesized that subjects would modulate digit placement for optimal force distribution and digit forces as a function of variable digit positions. All subjects learned to minimize object roll within the first three trials, and the unconstrained device was associated with significantly smaller grip forces but larger variability of digit positions. Importantly, however, digit load force modulation compensated for position variability, thus ensuring consistent object roll minimization on each trial. This indicates that subjects learned object manipulation by integrating sensorimotor memories with sensory feedback about digit positions. These results are discussed in the context of motor equivalence and sensorimotor integration of grasp kinematics and kinetics.

Two-Phase Item Selection Procedure for Flexible Content Balancing in CAT

ERIC Educational Resources Information Center

Cheng, Ying; Chang, Hua-Hua; Yi, Qing

2007-01-01

Content balancing is an important issue in the design and implementation of computerized adaptive testing (CAT). Content-balancing techniques that have been applied in fixed content balancing, where the number of items from each content area is fixed, include constrained CAT (CCAT), the modified multinomial model (MMM), modified constrained CAT…

Adaptive Devices for Aquatic Activities.

ERIC Educational Resources Information Center

Bradtke, Jane Silverman

1979-01-01

The article describes commercial as well as improvised and homemade equipment for teaching physically handicapped persons to swim. Descriptions address equipment for entering the pool (such as pool lifts, a transfer board, and a ramp); aids in the instructional process (kick boards, arm floats); and assorted games and materials (such as ropes,…

Rule-Based Motion Coordination for the Adaptive Suspension Vehicle on Ternary-Type Terrain

DTIC Science & Technology

1990-12-01

robot-window-array* nil) (defvar *robot..window..width* nil) (defvar * rebot -.window..heig)ht* nil) (defvar *terrain-buffer* nil) (defvar *terrain...cond ((momrber leg lift-able-leg. -test #’equal) log) (t nil)) .(dafmethod (test-overlap- rebot ipltcable-leg) (log) (nond ((and (member leg place-able

Investigating reduced bag weight as an effective risk mediator for mason tenders.

PubMed

Davis, Kermit G; Kotowski, Susan E; Albers, James; Marras, William S

2010-10-01

Masonry workers face some of the highest physical demands in the construction industry where large bags of masonry material weighing 42.7 kg are commonly handled by mason tenders who mix the mortar, distribute mortar and bricks/blocks, and erect/dismantle scaffolding throughout the day. The objective of this study was to determine the effectiveness of using half-weight bags (21.4 kg) on reducing the biomechanical loading, physiological response, and perceived exertions. Ten male subjects performed asymmetric lifting tasks simulating unloading bags from a pallet. Muscle activity, trunk kinematics, heart rate, blood pressure and subjective rating data were collected. Spine loads were predicted from a well-validated EMG-assisted model. Bag weight, lift type, bag height at origin, and asymmetry at destination significantly impacted the spine loads. While there was a 50% reduction in bag weight, the peak loads for the half-weight bags were only 25% less than the more available full-weight bags (a reduction of about 320 N of shear and 1000 N of compression). Lifts allowing movement of the feet reduced the loads by about 22% in shear and 27% in compression compared to constrained postures. Interestingly, cumulative spine loads were greater for the lighter bags than the heavy bags ( approximately 40%). The subjective ratings of exertion and risk were significantly lower for the lighter bags. RELEVANCE TO INDUSTRY: The reduction in peak spine loading for the half-weight bags, particularly at the higher heights and when the feet were allowed to move could significantly reduce the injuries of masonry workers. However, there were trade-offs with cumulative loads that may minimize the reduced risk. Overall, given the limited amount of time lifting bags, the reduction of peak loads.

A Globally Convergent Augmented Lagrangian Pattern Search Algorithm for Optimization with General Constraints and Simple Bounds

NASA Technical Reports Server (NTRS)

Lewis, Robert Michael; Torczon, Virginia

1998-01-01

We give a pattern search adaptation of an augmented Lagrangian method due to Conn, Gould, and Toint. The algorithm proceeds by successive bound constrained minimization of an augmented Lagrangian. In the pattern search adaptation we solve this subproblem approximately using a bound constrained pattern search method. The stopping criterion proposed by Conn, Gould, and Toint for the solution of this subproblem requires explicit knowledge of derivatives. Such information is presumed absent in pattern search methods; however, we show how we can replace this with a stopping criterion based on the pattern size in a way that preserves the convergence properties of the original algorithm. In this way we proceed by successive, inexact, bound constrained minimization without knowing exactly how inexact the minimization is. So far as we know, this is the first provably convergent direct search method for general nonlinear programming.

Iterative adaptive radiations of fossil canids show no evidence for diversity-dependent trait evolution.

PubMed

Slater, Graham J

2015-04-21

A long-standing hypothesis in adaptive radiation theory is that ecological opportunity constrains rates of phenotypic evolution, generating a burst of morphological disparity early in clade history. Empirical support for the early burst model is rare in comparative data, however. One possible reason for this lack of support is that most phylogenetic tests have focused on extant clades, neglecting information from fossil taxa. Here, I test for the expected signature of adaptive radiation using the outstanding 40-My fossil record of North American canids. Models implying time- and diversity-dependent rates of morphological evolution are strongly rejected for two ecologically important traits, body size and grinding area of the molar teeth. Instead, Ornstein-Uhlenbeck processes implying repeated, and sometimes rapid, attraction to distinct dietary adaptive peaks receive substantial support. Diversity-dependent rates of morphological evolution seem uncommon in clades, such as canids, that exhibit a pattern of replicated adaptive radiation. Instead, these clades might best be thought of as deterministic radiations in constrained Simpsonian subzones of a major adaptive zone. Support for adaptive peak models may be diagnostic of subzonal radiations. It remains to be seen whether early burst or ecological opportunity models can explain broader adaptive radiations, such as the evolution of higher taxa.

Iterative adaptive radiations of fossil canids show no evidence for diversity-dependent trait evolution

NASA Astrophysics Data System (ADS)

Slater, Graham J.

2015-04-01

A long-standing hypothesis in adaptive radiation theory is that ecological opportunity constrains rates of phenotypic evolution, generating a burst of morphological disparity early in clade history. Empirical support for the early burst model is rare in comparative data, however. One possible reason for this lack of support is that most phylogenetic tests have focused on extant clades, neglecting information from fossil taxa. Here, I test for the expected signature of adaptive radiation using the outstanding 40-My fossil record of North American canids. Models implying time- and diversity-dependent rates of morphological evolution are strongly rejected for two ecologically important traits, body size and grinding area of the molar teeth. Instead, Ornstein-Uhlenbeck processes implying repeated, and sometimes rapid, attraction to distinct dietary adaptive peaks receive substantial support. Diversity-dependent rates of morphological evolution seem uncommon in clades, such as canids, that exhibit a pattern of replicated adaptive radiation. Instead, these clades might best be thought of as deterministic radiations in constrained Simpsonian subzones of a major adaptive zone. Support for adaptive peak models may be diagnostic of subzonal radiations. It remains to be seen whether early burst or ecological opportunity models can explain broader adaptive radiations, such as the evolution of higher taxa.

High- and Low-Load Resistance Training: Interpretation and Practical Application of Current Research Findings.

PubMed

Fisher, James; Steele, James; Smith, Dave

2017-03-01

Our current state of knowledge regarding the load (lighter or heavier) lifted in resistance training programmes that will result in 'optimal' strength and hypertrophic adaptations is unclear. Despite this, position stands and recommendations are made based on, we propose, limited evidence to lift heavier weights. Here we discuss the state of evidence on the impact of load and how it, as a single variable, stimulates adaptations to take place and whether evidence for recommending heavier loads is available, well-defined, currently correctly interpreted or has been overlooked. Areas of discussion include electromyography amplitude, in vivo and in vitro methods of measuring hypertrophy, and motor schema and skill acquisition. The present piece clarifies to trainers and trainees the impact of these variables by discussing interpretation of synchronous and sequential motor unit recruitment and revisiting the size principle, poor agreement between whole-muscle cross-sectional area (CSA) and biopsy-determined changes in myofibril CSA, and neural adaptations around task specificity. Our opinion is that the practical implications of being able to self-select external load include reducing the need for specific facility memberships, motivating older persons or those who might be less confident using heavy loads, and allowing people to undertake home- or field-based resistance training intervention strategies that might ultimately improve exercise adherence.

Understanding and applying principles of social cognition and decision making in adaptive environmental governance

EPA Science Inventory

Environmental governance systems are under greater pressure to adapt and to cope with increased social and ecological uncertainty from stressors like climate change. We review principles of social cognition and decision making that shape and constrain how environmental governance...

Procedures for Selecting Items for Computerized Adaptive Tests.

ERIC Educational Resources Information Center

Kingsbury, G. Gage; Zara, Anthony R.

1989-01-01

Several classical approaches and alternative approaches to item selection for computerized adaptive testing (CAT) are reviewed and compared. The study also describes procedures for constrained CAT that may be added to classical item selection approaches to allow them to be used for applied testing. (TJH)

Simulating flame lift-off characteristics of diesel and biodiesel fuels using detailed chemical-kinetic mechanisms and LES turbulence model.

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

Som, S; Longman, D. E.; Luo, Z

2012-01-01

Combustion in direct-injection diesel engines occurs in a lifted, turbulent diffusion flame mode. Numerous studies indicate that the combustion and emissions in such engines are strongly influenced by the lifted flame characteristics, which are in turn determined by fuel and air mixing in the upstream region of the lifted flame, and consequently by the liquid breakup and spray development processes. From a numerical standpoint, these spray combustion processes depend heavily on the choice of underlying spray, combustion, and turbulence models. The present numerical study investigates the influence of different chemical kinetic mechanisms for diesel and biodiesel fuels, as well asmore » Reynolds-averaged Navier-Stokes (RANS) and large eddy simulation (LES) turbulence models on predicting flame lift-off lengths (LOLs) and ignition delays. Specifically, two chemical kinetic mechanisms for n-heptane (NHPT) and three for biodiesel surrogates are investigated. In addition, the RNG k-{epsilon} (RANS) model is compared to the Smagorinsky based LES turbulence model. Using adaptive grid resolution, minimum grid sizes of 250 {micro}m and 125 {micro}m were obtained for the RANS and LES cases respectively. Validations of these models were performed against experimental data from Sandia National Laboratories in a constant volume combustion chamber. Ignition delay and flame lift-off validations were performed at different ambient temperature conditions. The LES model predicts lower ignition delays and qualitatively better flame structures compared to the RNG k-{epsilon} model. The use of realistic chemistry and a ternary surrogate mixture, which consists of methyl decanoate, methyl 9-decenoate, and NHPT, results in better predicted LOLs and ignition delays. For diesel fuel though, only marginal improvements are observed by using larger size mechanisms. However, these improved predictions come at a significant increase in computational cost.« less

Interplanetary Supply Chain Risk Management

NASA Technical Reports Server (NTRS)

Galluzzi, Michael C.

2018-01-01

Emphasis on KSC ground processing operations, reduced spares up-mass lift requirements and campaign-level flexible path perspective for space systems support as Regolith-based ISM is achieved by; Network modeling for sequencing space logistics and in-space logistics nodal positioning to include feedstock. Economic modeling to assess ISM 3D printing adaption and supply chain risk.

Measures for improving the zeppelin airships for long distance transportation

NASA Technical Reports Server (NTRS)

Duerr, L. F.

1980-01-01

Factors to be considered in the construction of dirigibles include the design and weight of support structures, static and aerodynamic loads on the main ring, the annealing of support materials, and the dynamic gas pressure. Adaptations made for using helium as the lifting gas, and a method for extracting ballast are described.

Phenological plasticity will not help all species adapt to climate change.

PubMed

Duputié, Anne; Rutschmann, Alexis; Ronce, Ophélie; Chuine, Isabelle

2015-08-01

Concerns are rising about the capacity of species to adapt quickly enough to climate change. In long-lived organisms such as trees, genetic adaptation is slow, and how much phenotypic plasticity can help them cope with climate change remains largely unknown. Here, we assess whether, where and when phenological plasticity is and will be adaptive in three major European tree species. We use a process-based species distribution model, parameterized with extensive ecological data, and manipulate plasticity to suppress phenological variations due to interannual, geographical and trend climate variability, under current and projected climatic conditions. We show that phenological plasticity is not always adaptive and mostly affects fitness at the margins of the species' distribution and climatic niche. Under current climatic conditions, phenological plasticity constrains the northern range limit of oak and beech and the southern range limit of pine. Under future climatic conditions, phenological plasticity becomes strongly adaptive towards the trailing edges of beech and oak, but severely constrains the range and niche of pine. Our results call for caution when interpreting geographical variation in trait means as adaptive, and strongly point towards species distribution models explicitly taking phenotypic plasticity into account when forecasting species distribution under climate change scenarios. © 2015 John Wiley & Sons Ltd.

A method for modifying two-dimensional adaptive wind-tunnel walls including analytical and experimental verification

NASA Technical Reports Server (NTRS)

Everhart, J. L.

1983-01-01

The theoretical development of a simple and consistent method for removing the interference in adaptive-wall wind tunnels is reported. A Cauchy integral formulation of the velocities in an imaginary infinite extension of the real wind-tunnel flow is obtained and evaluated on a closed contour dividing the real and imaginary flow. The contour consists of the upper and lower effective wind-tunnel walls (wall plus boundary-layer displacement thickness) and upstream and downstream boundaries perpendicular to the axial tunnel flow. The resulting integral expressions for the streamwise and normal perturbation velocities on the contour are integrated by assuming a linear variation of the velocities between data-measurement stations along the contour. In an iterative process, the velocity components calculated on the upper and lower boundaries are then used to correct the shape of the wall to remove the interference. Convergence of the technique is shown numerically for the cases of a circular cylinder and a lifting and nonlifting NACA 0012 airfoil in incompressible flow. Experimental convergence at a transonic Mach number is demonstrated by using an NACA 0012 airfoil at zero lift.

Competitive learning with pairwise constraints.

PubMed

Covões, Thiago F; Hruschka, Eduardo R; Ghosh, Joydeep

2013-01-01

Constrained clustering has been an active research topic since the last decade. Most studies focus on batch-mode algorithms. This brief introduces two algorithms for on-line constrained learning, named on-line linear constrained vector quantization error (O-LCVQE) and constrained rival penalized competitive learning (C-RPCL). The former is a variant of the LCVQE algorithm for on-line settings, whereas the latter is an adaptation of the (on-line) RPCL algorithm to deal with constrained clustering. The accuracy results--in terms of the normalized mutual information (NMI)--from experiments with nine datasets show that the partitions induced by O-LCVQE are competitive with those found by the (batch-mode) LCVQE. Compared with this formidable baseline algorithm, it is surprising that C-RPCL can provide better partitions (in terms of the NMI) for most of the datasets. Also, experiments on a large dataset show that on-line algorithms for constrained clustering can significantly reduce the computational time.

Bioinspired wingtip devices: a pathway to improve aerodynamic performance during low Reynolds number flight.

PubMed

Lynch, Michael; Mandadzhiev, Boris; Wissa, Aimy

2018-03-20

Birds are highly capable and maneuverable fliers, traits not currently shared with current small unmanned aerial vehicles. They are able to achieve these flight capabilities by adapting the shape of their wings during flight in a variety of complex manners. One feature of bird wings, the primary feathers, separate to form wingtip gaps at the distal end of the wing. This paper presents bio-inspired wingtip devices with varying wingtip gap sizes, defined as the chordwise distance between wingtip devices, for operation in low Reynolds number conditions of Re  =  100 000, where many bird species operate. Lift and drag data was measured for planar and nonplanar wingtip devices with the total wingtip gap size ranging from 0% to 40% of the wing's mean chord. For a planar wing with a gap size of 20%, the mean coefficient of lift in the pre-stall region is increased by 7.25%, and the maximum coefficient of lift is increased by 5.6% compared to a configuration with no gaps. The nonplanar wingtip device was shown to reduce the induced drag. The effect of wingtip gap sizes is shown to be independent of the planarity/nonplanarity of the wingtip device, thereby allowing designers to decouple the wingtip parameters to tune the desired lift and drag produced.

An unsteady lifting surface method for single rotation propellers

NASA Technical Reports Server (NTRS)

Williams, Marc H.

1990-01-01

The mathematical formulation of a lifting surface method for evaluating the steady and unsteady loads induced on single rotation propellers by blade vibration and inflow distortion is described. The scheme is based on 3-D linearized compressible aerodynamics and presumes that all disturbances are simple harmonic in time. This approximation leads to a direct linear integral relation between the normal velocity on the blade (which is determined from the blade geometry and motion) and the distribution of pressure difference across the blade. This linear relation is discretized by breaking the blade up into subareas (panels) on which the pressure difference is treated as approximately constant, and constraining the normal velocity at one (control) point on each panel. The piece-wise constant loads can then be determined by Gaussian elimination. The resulting blade loads can be used in performance, stability and forced response predictions for the rotor. Mathematical and numerical aspects of the method are examined. A selection of results obtained from the method is presented. The appendices include various details of the derivation that were felt to be secondary to the main development in Section 1.

Effect of blocking tactile information from the fingertips on adaptation and execution of grip forces to friction at the grasping surface.

PubMed

Bilaloglu, Seda; Lu, Ying; Geller, Daniel; Rizzo, John Ross; Aluru, Viswanath; Gardner, Esther P; Raghavan, Preeti

2016-03-01

Adaptation of fingertip forces to friction at the grasping surface is necessary to prevent use of inadequate or excessive grip forces. In the current study we investigated the effect of blocking tactile information from the fingertips noninvasively on the adaptation and efficiency of grip forces to surface friction during precision grasp. Ten neurologically intact subjects grasped and lifted an instrumented grip device with 18 different frictional surfaces under three conditions: with bare hands or with a thin layer of plastic (Tegaderm) or an additional layer of foam affixed to the fingertips. The coefficient of friction at the finger-object interface of each surface was obtained for each subject with bare hands and Tegaderm by measuring the slip ratio (grip force/load force) at the moment of slip. We found that the foam layer reduced sensibility for two-point discrimination and pressure sensitivity at the fingertips, but Tegaderm did not. However, Tegaderm reduced static, but not dynamic, tactile discrimination. Adaptation of fingertip grip forces to surface friction measured by the rate of change of peak grip force, and grip force efficiency measured by the grip-load force ratio at lift, showed a proportional relationship with bare hands but were impaired with Tegaderm and foam. Activation of muscles engaged in precision grip also varied with the frictional surface with bare hands but not with Tegaderm and foam. The results suggest that sensitivity for static tactile discrimination is necessary for feedforward and feedback control of grip forces and for adaptive modulation of muscle activity during precision grasp. Copyright © 2016 the American Physiological Society.

Non-adaptive plasticity potentiates rapid adaptive evolution of gene expression in nature.

PubMed

Ghalambor, Cameron K; Hoke, Kim L; Ruell, Emily W; Fischer, Eva K; Reznick, David N; Hughes, Kimberly A

2015-09-17

Phenotypic plasticity is the capacity for an individual genotype to produce different phenotypes in response to environmental variation. Most traits are plastic, but the degree to which plasticity is adaptive or non-adaptive depends on whether environmentally induced phenotypes are closer or further away from the local optimum. Existing theories make conflicting predictions about whether plasticity constrains or facilitates adaptive evolution. Debate persists because few empirical studies have tested the relationship between initial plasticity and subsequent adaptive evolution in natural populations. Here we show that the direction of plasticity in gene expression is generally opposite to the direction of adaptive evolution. We experimentally transplanted Trinidadian guppies (Poecilia reticulata) adapted to living with cichlid predators to cichlid-free streams, and tested for evolutionary divergence in brain gene expression patterns after three to four generations. We find 135 transcripts that evolved parallel changes in expression within the replicated introduction populations. These changes are in the same direction exhibited in a native cichlid-free population, suggesting rapid adaptive evolution. We find 89% of these transcripts exhibited non-adaptive plastic changes in expression when the source population was reared in the absence of predators, as they are in the opposite direction to the evolved changes. By contrast, the remaining transcripts exhibiting adaptive plasticity show reduced population divergence. Furthermore, the most plastic transcripts in the source population evolved reduced plasticity in the introduction populations, suggesting strong selection against non-adaptive plasticity. These results support models predicting that adaptive plasticity constrains evolution, whereas non-adaptive plasticity potentiates evolution by increasing the strength of directional selection. The role of non-adaptive plasticity in evolution has received relatively little attention; however, our results suggest that it may be an important mechanism that predicts evolutionary responses to new environments.

Heat stress and dehydration in adapting for performance: Good, bad, both, or neither?

PubMed Central

Akerman, Ashley Paul; Tipton, Michael; Minson, Christopher T.; Cotter, James David

2016-01-01

ABSTRACT Physiological systems respond acutely to stress to minimize homeostatic disturbance, and typically adapt to chronic stress to enhance tolerance to that or a related stressor. It is legitimate to ask whether dehydration is a valuable stressor in stimulating adaptation per se. While hypoxia has had long-standing interest by athletes and researchers as an ergogenic aid, heat and nutritional stressors have had little interest until the past decade. Heat and dehydration are highly interlinked in their causation and the physiological strain they induce, so their individual roles in adaptation are difficult to delineate. The effectiveness of heat acclimation as an ergogenic aid remains unclear for team sport and endurance athletes despite several recent studies on this topic. Very few studies have examined the potential ergogenic (or ergolytic) adaptations to ecologically-valid dehydration as a stressor in its own right, despite longstanding evidence of relevant fluid-regulatory adaptations from short-term hypohydration. Transient and self-limiting dehydration (e.g., as constrained by thirst), as with most forms of stress, might have a time and a place in physiological or behavioral adaptations independently or by exacerbating other stressors (esp. heat); it cannot be dismissed without the appropriate evidence. The present review did not identify such evidence. Future research should identify how the magnitude and timing of dehydration might augment or interfere with the adaptive processes in behaviorally constrained versus unconstrained humans. PMID:28349082

Heat stress and dehydration in adapting for performance: Good, bad, both, or neither?

PubMed

Akerman, Ashley Paul; Tipton, Michael; Minson, Christopher T; Cotter, James David

2016-01-01

Physiological systems respond acutely to stress to minimize homeostatic disturbance, and typically adapt to chronic stress to enhance tolerance to that or a related stressor. It is legitimate to ask whether dehydration is a valuable stressor in stimulating adaptation per se . While hypoxia has had long-standing interest by athletes and researchers as an ergogenic aid, heat and nutritional stressors have had little interest until the past decade. Heat and dehydration are highly interlinked in their causation and the physiological strain they induce, so their individual roles in adaptation are difficult to delineate. The effectiveness of heat acclimation as an ergogenic aid remains unclear for team sport and endurance athletes despite several recent studies on this topic. Very few studies have examined the potential ergogenic (or ergolytic) adaptations to ecologically-valid dehydration as a stressor in its own right, despite longstanding evidence of relevant fluid-regulatory adaptations from short-term hypohydration. Transient and self-limiting dehydration (e.g., as constrained by thirst), as with most forms of stress, might have a time and a place in physiological or behavioral adaptations independently or by exacerbating other stressors (esp. heat); it cannot be dismissed without the appropriate evidence. The present review did not identify such evidence. Future research should identify how the magnitude and timing of dehydration might augment or interfere with the adaptive processes in behaviorally constrained versus unconstrained humans.

Spiders in Motion: Demonstrating Adaptation, Structure-Function Relationships, and Trade-Offs in Invertebrates

ERIC Educational Resources Information Center

Bowlin, Melissa S.; McLeer, Dorothy F.; Danielson-Francois, Anne M.

2014-01-01

Evolutionary history and structural considerations constrain all aspects of animal physiology. Constraints on invertebrate locomotion are especially straightforward for students to observe and understand. In this exercise, students use spiders to investigate the concepts of adaptation, structure-function relationships, and trade-offs. Students…

Electric dipole moments in natural supersymmetry

NASA Astrophysics Data System (ADS)

Nakai, Yuichiro; Reece, Matthew

2017-08-01

We discuss electric dipole moments (EDMs) in the framework of CP-violating natural supersymmetry (SUSY). Recent experimental results have significantly tightened constraints on the EDMs of electrons and of mercury, and substantial further progress is expected in the near future. We assess how these results constrain the parameter space of natural SUSY. In addition to our discussion of SUSY, we provide a set of general formulas for two-loop fermion EDMs, which can be applied to a wide range of models of new physics. In the SUSY context, the two-loop effects of stops and charginos respectively constrain the phases of A t μ and M 2 μ to be small in the natural part of parameter space. If the Higgs mass is lifted to 125 GeV by a new tree-level superpotential interaction and soft term with CP-violating phases, significant EDMs can arise from the two-loop effects of W bosons and tops. We compare the bounds arising from EDMs to those from other probes of new physics including colliders, b → sγ, and dark matter searches. Importantly, improvements in reach not only constrain higher masses, but require the phases to be significantly smaller in the natural parameter space at low mass. The required smallness of phases sharpens the CP problem of natural SUSY model building.

Method of assembling an electric power

DOEpatents

Rinehart, Lawrence E [Lake Oswego, OR; Romero, Guillermo L [Phoenix, AZ

2007-05-03

A method of assembling and providing an electric power apparatus. The method uses a heat resistant housing having a structure adapted to accommodate and retain a power circuit card and also including a bracket adapted to accommodate and constrain a rigid conductive member. A power circuit card having an electrical terminal is placed into the housing and a rigid conductive member into the bracket. The rigid conductive member is flow soldered to the electrical terminal, thereby exposing the heat resistant housing to heat and creating a solder bond. Finally, the rigid conductive member is affirmatively connected to the housing. The bracket constrains the rigid conductive member so that the act of affirmatively connecting does not weaken the solder bond.

Safe, Advanced, Adaptable Isolation System Eliminates the Need for Critical Lifts

NASA Technical Reports Server (NTRS)

Ginn, Starr

2011-01-01

The Starr Soft Support isolation system incorporates an automatically reconfigurable aircraft jack into NASA's existing 1-Hertz isolators. This enables an aircraft to float in mid-air without the need for a critical lift during ground vibration testing (GVT), significantly reducing testing risk, time, and costs. Currently incorporating the most advanced technology available, the 60,000-poundcapacity (27-metric-ton) isolation system is used for weight and measurement tests, control-surface free-play tests, and structural mode interaction tests without the need for any major reconfiguration, often saving days of time and significantly reducing labor costs. The Starr Soft Support isolation system consists of an aircraft-jacking device with three jacking points, each of which has an individual motor and accommodates up to 20,000 pounds (9 metric tons) for a total 60,000-pound (27-metric-ton) capacity. The system can be transported to the aircraft by forklift and placed at its jacking points using a pallet jack. The motors power the electric actuators, raising the aircraft above the ground until the landing gear can retract. Inflatable isolators then deploy, enabling the aircraft to float in mid-air, simulating a 1-Hertz free-free boundary condition. Inflatable isolators have been in use at NASA for years, enabling aircraft to literally float unsupported for highly accurate GVT. These isolators must be placed underneath the aircraft for this to occur. Traditionally, this is achieved by a critical lift a high-risk procedure in which a crane and flexible cord system are used to lift the aircraft. In contrast, the Starr Soft Support isolation system eliminates the need for critical lift by integrating the inflatable isolators into an aircraft jacking system. The system maintains vertical and horizontal isolating capabilities. The aircraft can be rolled onto the system, jacked up, and then the isolators can be inflated and positioned without any personnel needing to work underneath the aircraft. Also, the system accommodates changes in aircraft configuration, automatically adapting to changes in mass, and it can adjust the height of the isolators in one basic setup. Dryden personnel used the Starr Soft Support system to successfully perform a GVT on an F-15 being structurally modified by Gulfstream, Dryden's Gulfstream III used for science research and the crew exploration module and adaptor cone assembly.

Modified Backtracking Search Optimization Algorithm Inspired by Simulated Annealing for Constrained Engineering Optimization Problems

PubMed Central

Wang, Hailong; Sun, Yuqiu; Su, Qinghua; Xia, Xuewen

2018-01-01

The backtracking search optimization algorithm (BSA) is a population-based evolutionary algorithm for numerical optimization problems. BSA has a powerful global exploration capacity while its local exploitation capability is relatively poor. This affects the convergence speed of the algorithm. In this paper, we propose a modified BSA inspired by simulated annealing (BSAISA) to overcome the deficiency of BSA. In the BSAISA, the amplitude control factor (F) is modified based on the Metropolis criterion in simulated annealing. The redesigned F could be adaptively decreased as the number of iterations increases and it does not introduce extra parameters. A self-adaptive ε-constrained method is used to handle the strict constraints. We compared the performance of the proposed BSAISA with BSA and other well-known algorithms when solving thirteen constrained benchmarks and five engineering design problems. The simulation results demonstrated that BSAISA is more effective than BSA and more competitive with other well-known algorithms in terms of convergence speed. PMID:29666635

Efficient Compressed Sensing Based MRI Reconstruction using Nonconvex Total Variation Penalties

NASA Astrophysics Data System (ADS)

Lazzaro, D.; Loli Piccolomini, E.; Zama, F.

2016-10-01

This work addresses the problem of Magnetic Resonance Image Reconstruction from highly sub-sampled measurements in the Fourier domain. It is modeled as a constrained minimization problem, where the objective function is a non-convex function of the gradient of the unknown image and the constraints are given by the data fidelity term. We propose an algorithm, Fast Non Convex Reweighted (FNCR), where the constrained problem is solved by a reweighting scheme, as a strategy to overcome the non-convexity of the objective function, with an adaptive adjustment of the penalization parameter. We propose a fast iterative algorithm and we can prove that it converges to a local minimum because the constrained problem satisfies the Kurdyka-Lojasiewicz property. Moreover the adaptation of non convex l0 approximation and penalization parameters, by means of a continuation technique, allows us to obtain good quality solutions, avoiding to get stuck in unwanted local minima. Some numerical experiments performed on MRI sub-sampled data show the efficiency of the algorithm and the accuracy of the solution.

Plants in a crowded stand regulate their height growth so as to maintain similar heights to neighbours even when they have potential advantages in height growth.

PubMed

Nagashima, Hisae; Hikosaka, Kouki

2011-07-01

Although being tall is advantageous in light competition, plant height growth is often similar among dominant plants in crowded stands (height convergence). Previous theoretical studies have suggested that plants should not overtop neighbours because greater allocation to supporting tissues is necessary in taller plants, which in turn lowers leaf mass fraction and thus carbon gain. However, this model assumes that a competitor has the same potential of height growth as their neighbours, which does not necessarily account for the fact that height convergence occurs even among individuals with various biomass. Stands of individually potted plants of Chenopodium album were established, where target plants were lifted to overtop neighbours or lowered to be overtopped. Lifted plants were expected to keep overtopping because they intercept more light without increased allocation to stems, or to regulate their height to similar levels of neighbours, saving biomass allocation to the supporting organ. Lowered plants were expected to be suppressed due to the low light availability or to increase height growth so as to have similar height to the neighbours. Lifted plants reduced height growth in spite of the fact that they received higher irradiance than others. Lowered plants, on the other hand, increased the rate of stem elongation despite the reduced irradiance. Consequently, lifted and lowered plants converged to the same height. In contrast to the expectation, lifted plants did not increase allocation to leaf mass despite the decreased stem length. Rather, they allocated more biomass to roots, which might contribute to improvement of mechanical stability or water status. It is suggested that decreased leaf mass fraction is not the sole cost of overtopping neighbours. Wind blowing, which may enhance transpiration and drag force, might constrain growth of overtopping plants. The results show that plants in crowded stands regulate their height growth to maintain similar height to neighbours even when they have potential advantages in height growth. This might contribute to avoidance of stresses caused by wind blowing.

Maps of Structured Aerosol Activity During the MY 25 Planet-encircling Dust Storm on Mars

NASA Astrophysics Data System (ADS)

Noble, J.; Wilson, R. J.; Cantor, B. A.; Kahre, M. A.; Hollingsworth, J. L.; Bridger, A. F. C.; Haberle, R. M.; Barnes, J.

2016-12-01

We have produced a sequence of 42 global maps from Ls=165.1-187.7° that delimit the areal extent of structured aerosol activity based on a synthesis of Mars Global Surveyor (MGS) data, including Mars Orbiter Camera (MOC) daily global maps (DGMs) and wide angle imagery, Thermal Emission Spectrometer (TES) dust and H2O ice opacity, and Mars general circulation model (MGCM) derived dust opacity. The primary motivation of this work is to examine the temporal and spatial relationship between dust storms observed by MOC and baroclinic eddies inferred from Fast Fourier Synoptic Mapping (FFSM) of TES temperatures in order to study the initiation and evolution of Mars year (MY) 25 planet-encircling dust storm (PDS) precursor phase dust storms. A secondary motivation is to provide improved input to MGCM simulations. Assuming that structured dust storms indicate active dust lifting, these maps allow us to define potential dust lifting regions. This work has two implications for martian atmospheric science. First, integration of MGS data has enabled us to develop improved quantitative and qualitative descriptions of storm evolution that may be used to constrain estimates of dust lifting regions, horizontal dust distribution, and to infer associated circulations. Second, we believe that these maps provide better bases and constraints for modeling storm initiation. Based on our analysis of these MGS data, we propose the following working hypothesis to explain the dynamical processes responsible for PDS initiation and expansion. Six eastward-traveling transient baroclinic eddies triggered the MY 25 precursor storms in Hellas during Ls=176.2-184.6° due to the enhanced dust lifting associated with their low-level wind and stress fields. This was followed by a seventh eddy that contributed to expansion on Ls=186.3°. Increased opacity and temperatures from dust lifting associated with the first three eddies enhanced thermal tides which supported further storm initiation and expansion out of Hellas. Constructive interference of eddies and other circulation components including sublimation flow, anabatic winds (daytime upslope), and diurnal tides may have contributed to storm onset in, and expansion out of Hellas.

Arbitrary-level hanging nodes for adaptive hphp-FEM approximations in 3D

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

Pavel Kus; Pavel Solin; David Andrs

2014-11-01

In this paper we discuss constrained approximation with arbitrary-level hanging nodes in adaptive higher-order finite element methods (hphp-FEM) for three-dimensional problems. This technique enables using highly irregular meshes, and it greatly simplifies the design of adaptive algorithms as it prevents refinements from propagating recursively through the finite element mesh. The technique makes it possible to design efficient adaptive algorithms for purely hexahedral meshes. We present a detailed mathematical description of the method and illustrate it with numerical examples.

Variational Two-Particle Density Matrix Calculation for the Hubbard Model Below Half Filling Using Spin-Adapted Lifting Conditions

NASA Astrophysics Data System (ADS)

Verstichel, Brecht; van Aggelen, Helen; Poelmans, Ward; Van Neck, Dimitri

2012-05-01

The variational determination of the two-particle density matrix is an interesting, but not yet fully explored technique that allows us to obtain ground-state properties of a quantum many-body system without reference to an N-particle wave function. The one-dimensional fermionic Hubbard model has been studied before with this method, using standard two- and three-index conditions on the density matrix [J. R. Hammond , Phys. Rev. A 73, 062505 (2006)PLRAAN1050-294710.1103/PhysRevA.73.062505], while a more recent study explored so-called subsystem constraints [N. Shenvi , Phys. Rev. Lett. 105, 213003 (2010)PRLTAO0031-900710.1103/PhysRevLett.105.213003]. These studies reported good results even with only standard two-index conditions, but have always been limited to the half-filled lattice. In this Letter, we establish the fact that the two-index approach fails for other fillings. In this case, a subset of three-index conditions is absolutely needed to describe the correct physics in the strong-repulsion limit. We show that applying lifting conditions [J. R. Hammond , Phys. Rev. APLRAAN1050-2947 71, 062503 (2005)10.1103/PhysRevA.71.062503] is the most economical way to achieve this, while still avoiding the computationally much heavier three-index conditions. A further extension to spin-adapted lifting conditions leads to increased accuracy in the intermediate repulsion regime. At the same time, we establish the feasibility of such studies to the more complicated phase diagram in two-dimensional Hubbard models.

PAPR-Constrained Pareto-Optimal Waveform Design for OFDM-STAP Radar

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

Sen, Satyabrata

We propose a peak-to-average power ratio (PAPR) constrained Pareto-optimal waveform design approach for an orthogonal frequency division multiplexing (OFDM) radar signal to detect a target using the space-time adaptive processing (STAP) technique. The use of an OFDM signal does not only increase the frequency diversity of our system, but also enables us to adaptively design the OFDM coefficients in order to further improve the system performance. First, we develop a parametric OFDM-STAP measurement model by considering the effects of signaldependent clutter and colored noise. Then, we observe that the resulting STAP-performance can be improved by maximizing the output signal-to-interference-plus-noise ratiomore » (SINR) with respect to the signal parameters. However, in practical scenarios, the computation of output SINR depends on the estimated values of the spatial and temporal frequencies and target scattering responses. Therefore, we formulate a PAPR-constrained multi-objective optimization (MOO) problem to design the OFDM spectral parameters by simultaneously optimizing four objective functions: maximizing the output SINR, minimizing two separate Cramer-Rao bounds (CRBs) on the normalized spatial and temporal frequencies, and minimizing the trace of CRB matrix on the target scattering coefficients estimations. We present several numerical examples to demonstrate the achieved performance improvement due to the adaptive waveform design.« less

The biomechanical and perceptual influence of chain resistance on the performance of the olympic clean.

PubMed

Berning, Joseph M; Coker, Cheryl A; Briggs, Doug

2008-03-01

Proponents of chain training suggest that using chains hung from the ends of barbells rather than using conventional barbells alone enhances strength, power, and neuromuscular adaptations. The purpose of this study was to determine whether a conventional barbell with chains compared to a conventional barbell without chains would affect the performance of an Olympic Clean. The subjects were also asked regarding their perception of how chains affected their lifting. Four male and 3 female competitive weightlifters who used chains as part of their training participated in the study. The testing protocol compared the subjects' lifting 80% and 85% of their 1 repetition maximum (1RM) using conventional barbells and their lifting 80% and 85% of their 1RM using chains (75% conventional barbells + 5% chains and 80% conventional barbells + 5% chains, respectively). Video analysis evaluated the bar's vertical displacement and velocity and the rate of force production. Vertical ground reaction forces for the first-pull, unweighting, and second-pull phases of the lift were evaluated by using a force plate. After testing, the subjects completed a 2-item questionnaire asking individual perception of the effects of the chains. The results showed no significant difference for condition for any of the variables examined. In contrast, all subjects perceived that the chains required a greater effort. In conclusion, the results indicated that the addition of chains provided no greater value over lifting conventional barbells alone in the performance of the Olympic Clean, although the subjects perceived the chains to have a positive effect.

Numerical design of an adaptive aileron

NASA Astrophysics Data System (ADS)

Amendola, Gianluca; Dimino, Ignazio; Concilio, Antonio; Magnifico, Marco; Pecora, Rosario

2016-04-01

The study herein described is aimed at investigating the feasibility of an innovative full-scale camber morphing aileron device. In the framework of the "Adaptive Aileron" project, an international cooperation between Italy and Canada, this goal was carried out with the integration of different morphing concepts in a wing-tip prototype. As widely demonstrated in recent European projects such as Clean Sky JTI and SARISTU, wing trailing edge morphing may lead to significant drag reduction (up to 6%) in off-design flight points by adapting chord-wise camber variations in cruise to compensate A/C weight reduction following fuel consumption. Those researches focused on the flap region as the most immediate solution to implement structural adaptations. However, there is also a growing interest in extending morphing functionalities to the aileron region preserving its main functionality in controlling aircraft directional stability. In fact, the external region of the wing seems to be the most effective in producing "lift over drag" improvements by morphing. Thus, the objective of the presented research is to achieve a certain drag reduction in off-design flight points by adapting wing shape and lift distribution following static deflections. In perspective, the developed device could also be used as a load alleviation system to reduce gust effects, augmenting its frequency bandwidth. In this paper, the preliminary design of the adaptive aileron is first presented, assessed on the base of the external aerodynamic loads. The primary structure is made of 5 segmented ribs, distributed along 4 bays, each splitted into three consecutive parts, connected with spanwise stringers. The aileron shape modification is then implemented by means of an actuation system, based on a classical quick-return mechanism, opportunely suited for the presented application. Finite element analyses were assessed for properly sizing the load-bearing structure and actuation systems and for characterizing their dynamic behavior. Obtained results are reported and widely discussed.

On-Board Generation of Three-Dimensional Constrained Entry Trajectories

NASA Technical Reports Server (NTRS)

Shen, Zuojun; Lu, Ping; Jackson, Scott (Technical Monitor)

2002-01-01

A methodology for very fast design of 3DOF entry trajectories subject to all common inequality and equality constraints is developed. The approach make novel use of the well known quasi-equilibrium glide phenomenon in lifting entry as a center piece for conveniently enforcing the inequality constraints which are otherwise difficulty to handle. The algorithm is able to generate a complete feasible 3DOF entry trajectory, given the entry conditions, values of constraint parameters, and final conditions in about 2 seconds on a PC. Numerical simulations with the X-33 vehicle model for various entry missions to land at Kennedy Space Center will be presented.

Power and weight considerations in small, agile quadrotors

NASA Astrophysics Data System (ADS)

Mulgaonkar, Yash; Whitzer, Michael; Morgan, Brian; Kroninger, Christopher M.; Harrington, Aaron M.; Kumar, Vijay

2014-06-01

The development of autonomous Micro Aerial Vehicles (MAVs) is significantly constrained by their size, weight and power consumption. In this paper, we explore the energetics of quadrotor platforms and study the scaling of mass, inertia, lift and drag with their characteristic length. The effects of length scale on masses and inertias associated with various components are also investigated. Additionally, a study of Lithium Polymer battery performance is presented in terms of specific power and specific energy. Finally, we describe the power and energy consumption for different quadrotors and explore the dependence on size and mass for static hover tests as well as representative maneuvers.

Comparison of wing-span averaging effects on lift, rolling moment, and bending moment for two span load distributions and for two turbulence representations

NASA Technical Reports Server (NTRS)

Lichtenstein, J. H.

1978-01-01

An analytical method of computing the averaging effect of wing-span size on the loading of a wing induced by random turbulence was adapted for use on a digital electronic computer. The turbulence input was assumed to have a Dryden power spectral density. The computations were made for lift, rolling moment, and bending moment for two span load distributions, rectangular and elliptic. Data are presented to show the wing-span averaging effect for wing-span ratios encompassing current airplane sizes. The rectangular wing-span loading showed a slightly greater averaging effect than did the elliptic loading. In the frequency range most bothersome to airplane passengers, the wing-span averaging effect can reduce the normal lift load, and thus the acceleration, by about 7 percent for a typical medium-sized transport. Some calculations were made to evaluate the effect of using a Von Karman turbulence representation. These results showed that using the Von Karman representation generally resulted in a span averaging effect about 3 percent larger.

A Comparison of Procedures for Content-Sensitive Item Selection in Computerized Adaptive Tests.

ERIC Educational Resources Information Center

Kingsbury, G. Gage; Zara, Anthony R.

1991-01-01

This simulation investigated two procedures that reduce differences between paper-and-pencil testing and computerized adaptive testing (CAT) by making CAT content sensitive. Results indicate that the price in terms of additional test items of using constrained CAT for content balancing is much smaller than that of using testlets. (SLD)

Optimal Item Pool Design for a Highly Constrained Computerized Adaptive Test

ERIC Educational Resources Information Center

He, Wei

2010-01-01

Item pool quality has been regarded as one important factor to help realize enhanced measurement quality for the computerized adaptive test (CAT) (e.g., Flaugher, 2000; Jensema, 1977; McBride & Wise, 1976; Reckase, 1976; 2003; van der Linden, Ariel, & Veldkamp, 2006; Veldkamp & van der Linden, 2000; Xing & Hambleton, 2004). However, studies are…

Adaptive wing structures

NASA Astrophysics Data System (ADS)

Perkins, David A.; Reed, John L., Jr.; Havens, Ernie

2004-07-01

Cornerstone Research Group, Inc. (CRG), with specific no-cost guidance and support from Lockheed Martin, proposed to significantly increase the capability of loitering Unmanned Air Vehicles (UAVs) by developing a unique adaptive wing structure. This technology will offer significant operational benefit to air vehicles of this type currently under development. The development of this adaptive wing structure will enable such aircraft to adapt their wing configuration to maximize efficiency in each flight regime experienced during their mission. Additionally, the benefits of this development program will enhance the agility and maneuverability of the vehicle; therefore increasing its mission capability. The specific morphing ability CRG proposed to develop was a controlled expansion and contraction of the wing chord, which increases the wing planform area and therefore the lift produced. CRG proved feasibility of this concept and developed a sub-scale prototype integrating smart materials developed at CRG.

KSC-97PC1110

NASA Image and Video Library

1997-07-22

Flight mechanics from NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif., lower the Cassini spacecraft onto its launch vehicle adapter in KSC’s Payload Hazardous Servicing Facility. The adapter will later be mated to a Titan IV/Centaur expendable launch vehicle that will lift Cassini into space. Scheduled for launch in October, the Cassini mission, a joint US-European four-year orbital surveillance of Saturn's atmosphere and magnetosphere, its rings, and its moons, seeks insight into the origins and evolution of the early solar system. It will take seven years for the spacecraft to reach Saturn. JPL is managing the Cassini project for NASA

Eddy Current Rail Inspection Using AC Bridge Techniques.

PubMed

Liu, Ze; Koffman, Andrew D; Waltrip, Bryan C; Wang, Yicheng

2013-01-01

AC bridge techniques commonly used for precision impedance measurements have been adapted to develop an eddy current sensor for rail defect detection. By using two detection coils instead of just one as in a conventional sensor, we can balance out the large baseline signals corresponding to a normal rail. We have significantly enhanced the detection sensitivity of the eddy current method by detecting and demodulating the differential signal of the two coils induced by rail defects, using a digital lock-in amplifier algorithm. We have also explored compensating for the lift-off effect of the eddy current sensor due to vibrations by using the summing signal of the detection coils to measure the lift-off distance. The dominant component of the summing signal is a constant resulting from direct coupling from the excitation coil, which can be experimentally determined. The remainder of the summing signal, which decreases as the lift-off distance increases, is induced by the secondary eddy current. This dependence on the lift-off distance is used to calibrate the differential signal, allowing for a more accurate characterization of the defects. Simulated experiments on a sample rail have been performed using a computer controlled X-Y moving table with the X-axis mimicking the train's motion and the Y-axis mimicking the train's vibrational bumping. Experimental results demonstrate the effectiveness of the new detection method.

Monitoring is not enough: on the need for a model-based approach to migratory bird management

USGS Publications Warehouse

Nichols, J.D.; Bonney, Rick; Pashley, David N.; Cooper, Robert; Niles, Larry

2000-01-01

Informed management requires information about system state and about effects of potential management actions on system state. Population monitoring can provide the needed information about system state, as well as information that can be used to investigate effects of management actions. Three methods for investigating effects of management on bird populations are (1) retrospective analysis, (2) formal experimentation and constrained-design studies, and (3) adaptive management. Retrospective analyses provide weak inferences, regardless of the quality of the monitoring data. The active use of monitoring data in experimental or constrained-design studies or in adaptive management is recommended. Under both approaches, learning occurs via the comparison of estimates from the monitoring program with predictions from competing management models.

An Adaptive Numeric Predictor-corrector Guidance Algorithm for Atmospheric Entry Vehicles. M.S. Thesis - MIT, Cambridge

NASA Technical Reports Server (NTRS)

Spratlin, Kenneth Milton

1987-01-01

An adaptive numeric predictor-corrector guidance is developed for atmospheric entry vehicles which utilize lift to achieve maximum footprint capability. Applicability of the guidance design to vehicles with a wide range of performance capabilities is desired so as to reduce the need for algorithm redesign with each new vehicle. Adaptability is desired to minimize mission-specific analysis and planning. The guidance algorithm motivation and design are presented. Performance is assessed for application of the algorithm to the NASA Entry Research Vehicle (ERV). The dispersions the guidance must be designed to handle are presented. The achievable operational footprint for expected worst-case dispersions is presented. The algorithm performs excellently for the expected dispersions and captures most of the achievable footprint.

Pixel-level multisensor image fusion based on matrix completion and robust principal component analysis

NASA Astrophysics Data System (ADS)

Wang, Zhuozheng; Deller, J. R.; Fleet, Blair D.

2016-01-01

Acquired digital images are often corrupted by a lack of camera focus, faulty illumination, or missing data. An algorithm is presented for fusion of multiple corrupted images of a scene using the lifting wavelet transform. The method employs adaptive fusion arithmetic based on matrix completion and self-adaptive regional variance estimation. Characteristics of the wavelet coefficients are used to adaptively select fusion rules. Robust principal component analysis is applied to low-frequency image components, and regional variance estimation is applied to high-frequency components. Experiments reveal that the method is effective for multifocus, visible-light, and infrared image fusion. Compared with traditional algorithms, the new algorithm not only increases the amount of preserved information and clarity but also improves robustness.

A modified adjoint-based grid adaptation and error correction method for unstructured grid

NASA Astrophysics Data System (ADS)

Cui, Pengcheng; Li, Bin; Tang, Jing; Chen, Jiangtao; Deng, Youqi

2018-05-01

Grid adaptation is an important strategy to improve the accuracy of output functions (e.g. drag, lift, etc.) in computational fluid dynamics (CFD) analysis and design applications. This paper presents a modified robust grid adaptation and error correction method for reducing simulation errors in integral outputs. The procedure is based on discrete adjoint optimization theory in which the estimated global error of output functions can be directly related to the local residual error. According to this relationship, local residual error contribution can be used as an indicator in a grid adaptation strategy designed to generate refined grids for accurately estimating the output functions. This grid adaptation and error correction method is applied to subsonic and supersonic simulations around three-dimensional configurations. Numerical results demonstrate that the sensitive grids to output functions are detected and refined after grid adaptation, and the accuracy of output functions is obviously improved after error correction. The proposed grid adaptation and error correction method is shown to compare very favorably in terms of output accuracy and computational efficiency relative to the traditional featured-based grid adaptation.

The sail wing windmill and its adaptation for use in rural India

NASA Technical Reports Server (NTRS)

Sherman, M. M.

1973-01-01

An 8 meter-diameter prototype sail wing windmill is reported that uses a one meter-diameter bullock cartwheel to which three bamboo poles are latched in a triangular pattern with overlapping ends, to form the airframe for cloth sails. This device lifts 300 pounds to a height of 20 feet in one minute in a 10 mph wind.

The 1 Repetition Maximum Mechanics of a High-Handle Hexagonal Bar Deadlift Compared With a Conventional Deadlift as Measured by a Linear Position Transducer.

PubMed

Lockie, Robert G; Moreno, Matthew R; Lazar, Adrina; Risso, Fabrice G; Liu, Tricia M; Stage, Alyssa A; Birmingham-Babauta, Samantha A; Torne, Ibett A; Stokes, John J; Giuliano, Dominic V; Davis, DeShaun L; Orjalo, Ashley J; Callaghan, Samuel J

2018-01-01

Lockie, RG, Moreno, MR, Lazar, A, Risso, FG, Liu, TM, Stage, AA, Birmingham-Babauta, SA, Torne, IA, Stokes, JJ, Giuliano, DV, Davis, DL, Orjalo, AJ, and Callaghan, SJ. The 1 repetition maximum mechanics of a high-handle hexagonal bar deadlift compared with a conventional deadlift as measured by a linear position transducer. J Strength Cond Res 32(1): 150-161, 2018-The high-handle hexagonal bar deadlift (HHBD), a variation of the conventional deadlift (CD), is said to reduce the lift range of motion, which may change the mechanics of the lift. However, no research has investigated this. This study compared the mechanics between a 1 repetition maximum (1RM) CD and HHBD. Thirty-one strength-trained subjects (21 men, 10 women) completed a 1RM CD and HHBD. A linear position transducer measured lift distance, duration, and work; and peak and mean power, velocity, and force. The presence of a sticking region (SR) was determined for each lift. A repeated-measures analysis of variance (ANOVA) calculated differences between 1RM CD and HHBD mechanics. A one-way ANOVA compared the mechanics of each lift between subjects who exhibited an SR or not, and the SR between the CD and HHBD. Significance was set at p < 0.01. Subjects lifted a greater load in the HHBD (154.50 ± 45.29 kg) compared with the CD (134.72 ± 40.63 kg). Lift distance and duration were 22 and 25% shorter during the 1RM HHBD, respectively. The HHBD featured greater peak power and velocity, and peak and mean force; more work was done in the CD. Most subjects did not exhibit a CD (68%) or HHBD (77%) SR. There were no differences in CD or HHBD mechanics between subjects with or without an SR, and no differences in SR region distance or duration between the CD and HHBD. Greater force can be generated in the HHBD, which could have implications for strength-training adaptations over time.

Comparative Analysis of Japanese Three-Spined Stickleback Clades Reveals the Pacific Ocean Lineage Has Adapted to Freshwater Environments while the Japan Sea Has Not

PubMed Central

Ravinet, Mark; Takeuchi, Naoko; Kume, Manabu; Mori, Seiichi; Kitano, Jun

2014-01-01

Divergent selection and adaptive divergence can increase phenotypic diversification amongst populations and lineages. Yet adaptive divergence between different environments, habitats or niches does not occur in all lineages. For example, the colonization of freshwater environments by ancestral marine species has triggered adaptive radiation and phenotypic diversification in some taxa but not in others. Studying closely related lineages differing in their ability to diversify is an excellent means of understanding the factors promoting and constraining adaptive evolution. A well-known example of the evolution of increased phenotypic diversification following freshwater colonization is the three-spined stickleback. Two closely related stickleback lineages, the Pacific Ocean and the Japan Sea occur in Japan. However, Japanese freshwater stickleback populations are derived from the Pacific Ocean lineage only, suggesting the Japan Sea lineage is unable to colonize freshwater. Using stable isotope data and trophic morphology, we first show higher rates of phenotypic and ecological diversification between marine and freshwater populations within the Pacific Ocean lineage, confirming adaptive divergence has occurred between the two lineages and within the Pacific Ocean lineage but not in the Japan Sea lineage. We further identified consistent divergence in diet and foraging behaviour between marine forms from each lineage, confirming Pacific Ocean marine sticklebacks, from which all Japanese freshwater populations are derived, are better adapted to freshwater environments than Japan Sea sticklebacks. We suggest adaptive divergence between ancestral marine populations may have played a role in constraining phenotypic diversification and adaptive evolution in Japanese sticklebacks. PMID:25460163

Comparative analysis of Japanese three-spined stickleback clades reveals the Pacific Ocean lineage has adapted to freshwater environments while the Japan Sea has not.

PubMed

Ravinet, Mark; Takeuchi, Naoko; Kume, Manabu; Mori, Seiichi; Kitano, Jun

2014-01-01

Divergent selection and adaptive divergence can increase phenotypic diversification amongst populations and lineages. Yet adaptive divergence between different environments, habitats or niches does not occur in all lineages. For example, the colonization of freshwater environments by ancestral marine species has triggered adaptive radiation and phenotypic diversification in some taxa but not in others. Studying closely related lineages differing in their ability to diversify is an excellent means of understanding the factors promoting and constraining adaptive evolution. A well-known example of the evolution of increased phenotypic diversification following freshwater colonization is the three-spined stickleback. Two closely related stickleback lineages, the Pacific Ocean and the Japan Sea occur in Japan. However, Japanese freshwater stickleback populations are derived from the Pacific Ocean lineage only, suggesting the Japan Sea lineage is unable to colonize freshwater. Using stable isotope data and trophic morphology, we first show higher rates of phenotypic and ecological diversification between marine and freshwater populations within the Pacific Ocean lineage, confirming adaptive divergence has occurred between the two lineages and within the Pacific Ocean lineage but not in the Japan Sea lineage. We further identified consistent divergence in diet and foraging behaviour between marine forms from each lineage, confirming Pacific Ocean marine sticklebacks, from which all Japanese freshwater populations are derived, are better adapted to freshwater environments than Japan Sea sticklebacks. We suggest adaptive divergence between ancestral marine populations may have played a role in constraining phenotypic diversification and adaptive evolution in Japanese sticklebacks.

Regime shifts and panarchies in regional scale social-ecological water systems

PubMed Central

Gunderson, Lance; Cosens, Barbara A.; Chaffin, Brian C.; (Tom) Arnold, Craig A.; Fremier, Alexander K.; Garmestani, Ahjond S.; Craig, Robin Kundis; Gosnell, Hannah; Birge, Hannah E.; Allen, Craig R.; Benson, Melinda H.; Morrison, Ryan R.; Stone, Mark C.; Hamm, Joseph A.; Nemec, Kristine; Schlager, Edella; Llewellyn, Dagmar

2018-01-01

In this article we summarize histories of nonlinear, complex interactions among societal, legal, and ecosystem dynamics in six North American water basins, as they respond to changing climate. These case studies were chosen to explore the conditions for emergence of adaptive governance in heavily regulated and developed social-ecological systems nested within a hierarchical governmental system. We summarize resilience assessments conducted in each system to provide a synthesis and reference by the other articles in this special feature. We also present a general framework used to evaluate the interactions between society and ecosystem regimes and the governance regimes chosen to mediate those interactions. The case studies show different ways that adaptive governance may be triggered, facilitated, or constrained by ecological and/or legal processes. The resilience assessments indicate that complex interactions among the governance and ecosystem components of these systems can produce different trajectories, which include patterns of (a) development and stabilization, (b) cycles of crisis and recovery, which includes lurches in adaptation and learning, and (3) periods of innovation, novelty, and transformation. Exploration of cross scale (Panarchy) interactions among levels and sectors of government and society illustrate that they may constrain development trajectories, but may also provide stability during crisis or innovation at smaller scales; create crises, but may also facilitate recovery; and constrain system transformation, but may also provide windows of opportunity in which transformation, and the resources to accomplish it, may occur. The framework is the starting point for our exploration of how law might play a role in enhancing the capacity of social-ecological systems to adapt to climate change. PMID:29780427

Regime shifts and panarchies in regional scale social-ecological water systems.

PubMed

Gunderson, Lance; Cosens, Barbara A; Chaffin, Brian C; Tom Arnold, Craig A; Fremier, Alexander K; Garmestani, Ahjond S; Craig, Robin Kundis; Gosnell, Hannah; Birge, Hannah E; Allen, Craig R; Benson, Melinda H; Morrison, Ryan R; Stone, Mark C; Hamm, Joseph A; Nemec, Kristine; Schlager, Edella; Llewellyn, Dagmar

2017-03-17

In this article we summarize histories of nonlinear, complex interactions among societal, legal, and ecosystem dynamics in six North American water basins, as they respond to changing climate. These case studies were chosen to explore the conditions for emergence of adaptive governance in heavily regulated and developed social-ecological systems nested within a hierarchical governmental system. We summarize resilience assessments conducted in each system to provide a synthesis and reference by the other articles in this special feature. We also present a general framework used to evaluate the interactions between society and ecosystem regimes and the governance regimes chosen to mediate those interactions. The case studies show different ways that adaptive governance may be triggered, facilitated, or constrained by ecological and/or legal processes. The resilience assessments indicate that complex interactions among the governance and ecosystem components of these systems can produce different trajectories, which include patterns of (a) development and stabilization, (b) cycles of crisis and recovery, which includes lurches in adaptation and learning, and (3) periods of innovation, novelty, and transformation. Exploration of cross scale (Panarchy) interactions among levels and sectors of government and society illustrate that they may constrain development trajectories, but may also provide stability during crisis or innovation at smaller scales; create crises, but may also facilitate recovery; and constrain system transformation, but may also provide windows of opportunity in which transformation, and the resources to accomplish it, may occur. The framework is the starting point for our exploration of how law might play a role in enhancing the capacity of social-ecological systems to adapt to climate change.

Regime shifts and panarchies in regional scale social-ecological water systems

USGS Publications Warehouse

Gunderson, Lance; Cosens, Barbara; Chaffin, Brian C.; Arnold, Craig Anthony (Tony); Fremier, Alexander K.; Garmestani, Ahjond S.; Kundis Craig, Robin; Gosnell, Hannah; Birge, Hannah E.; Allen, Craig R.; Benson, Melinda H.; Morrison, Ryan R.; Stone, Mark; Hamm, Joseph A.; Nemec, Kristine T.; Schlager, Edella; Llewellyn, Dagmar

2017-01-01

In this article we summarize histories of nonlinear, complex interactions among societal, legal, and ecosystem dynamics in six North American water basins, as they respond to changing climate. These case studies were chosen to explore the conditions for emergence of adaptive governance in heavily regulated and developed social-ecological systems nested within a hierarchical governmental system. We summarize resilience assessments conducted in each system to provide a synthesis and reference by the other articles in this special feature. We also present a general framework used to evaluate the interactions between society and ecosystem regimes and the governance regimes chosen to mediate those interactions. The case studies show different ways that adaptive governance may be triggered, facilitated, or constrained by ecological and/or legal processes. The resilience assessments indicate that complex interactions among the governance and ecosystem components of these systems can produce different trajectories, which include patterns of (a) development and stabilization, (b) cycles of crisis and recovery, which includes lurches in adaptation and learning, and (3) periods of innovation, novelty, and transformation. Exploration of cross scale (Panarchy) interactions among levels and sectors of government and society illustrate that they may constrain development trajectories, but may also provide stability during crisis or innovation at smaller scales; create crises, but may also facilitate recovery; and constrain system transformation, but may also provide windows of opportunity in which transformation, and the resources to accomplish it, may occur. The framework is the starting point for our exploration of how law might play a role in enhancing the capacity of social-ecological systems to adapt to climate change.

Selecting Learning Tasks: Effects of Adaptation and Shared Control on Learning Efficiency and Task Involvement

ERIC Educational Resources Information Center

Corbalan, Gemma; Kester, Liesbeth; van Merrienboer, Jeroen J. G.

2008-01-01

Complex skill acquisition by performing authentic learning tasks is constrained by limited working memory capacity [Baddeley, A. D. (1992). Working memory. "Science, 255", 556-559]. To prevent cognitive overload, task difficulty and support of each newly selected learning task can be adapted to the learner's competence level and perceived task…

Implementing Sympson-Hetter Item-Exposure Control in a Shadow-Test Approach to Constrained Adaptive Testing

ERIC Educational Resources Information Center

Veldkamp, Bernard P.; van der Linden, Wim J.

2008-01-01

In most operational computerized adaptive testing (CAT) programs, the Sympson-Hetter (SH) method is used to control the exposure of the items. Several modifications and improvements of the original method have been proposed. The Stocking and Lewis (1998) version of the method uses a multinomial experiment to select items. For severely constrained…

Secure Service Proxy: A CoAP(s) Intermediary for a Securer and Smarter Web of Things

PubMed Central

Van den Abeele, Floris; Moerman, Ingrid; Demeester, Piet

2017-01-01

As the IoT continues to grow over the coming years, resource-constrained devices and networks will see an increase in traffic as everything is connected in an open Web of Things. The performance- and function-enhancing features are difficult to provide in resource-constrained environments, but will gain importance if the WoT is to be scaled up successfully. For example, scalable open standards-based authentication and authorization will be important to manage access to the limited resources of constrained devices and networks. Additionally, features such as caching and virtualization may help further reduce the load on these constrained systems. This work presents the Secure Service Proxy (SSP): a constrained-network edge proxy with the goal of improving the performance and functionality of constrained RESTful environments. Our evaluations show that the proposed design reaches its goal by reducing the load on constrained devices while implementing a wide range of features as different adapters. Specifically, the results show that the SSP leads to significant savings in processing, network traffic, network delay and packet loss rates for constrained devices. As a result, the SSP helps to guarantee the proper operation of constrained networks as these networks form an ever-expanding Web of Things. PMID:28696393

Secure Service Proxy: A CoAP(s) Intermediary for a Securer and Smarter Web of Things.

PubMed

Van den Abeele, Floris; Moerman, Ingrid; Demeester, Piet; Hoebeke, Jeroen

2017-07-11

As the IoT continues to grow over the coming years, resource-constrained devices and networks will see an increase in traffic as everything is connected in an open Web of Things. The performance- and function-enhancing features are difficult to provide in resource-constrained environments, but will gain importance if the WoT is to be scaled up successfully. For example, scalable open standards-based authentication and authorization will be important to manage access to the limited resources of constrained devices and networks. Additionally, features such as caching and virtualization may help further reduce the load on these constrained systems. This work presents the Secure Service Proxy (SSP): a constrained-network edge proxy with the goal of improving the performance and functionality of constrained RESTful environments. Our evaluations show that the proposed design reaches its goal by reducing the load on constrained devices while implementing a wide range of features as different adapters. Specifically, the results show that the SSP leads to significant savings in processing, network traffic, network delay and packet loss rates for constrained devices. As a result, the SSP helps to guarantee the proper operation of constrained networks as these networks form an ever-expanding Web of Things.

LCL: (Locked Cheek Lift) Three-Dimensional Cheek Lift and Inferior Palpebral Rejuvenation.

PubMed

Divaris, Marc; Sabri, Ebaa; Cancemi, Gianfranco; Daury, Richard

2018-06-01

Many recent advances in face lift techniques have been made to reverse the aging process of the mid-face. In this study, we present a new technique by which mid-face rejuvenation can be achieved in double-angle vectors and allows adaption to the underlying bony structure. The locked cheek lift (LCL) allows effective, simple and rapid lifting of the malar fat pad in two planes. Correction of the curvature of the face and reduction of the height of lid cheek junction distance can be achieved without an incision at the lower eyelid. In total, 115 patients (77 females and 38 males) have been operated on using the LCL technique by a single surgeon; patient ages ranged between 37 and 71 years old (average = 51). Follow-up was performed by the same team for a year postoperatively. The facial expression and lid cheek distance have been evaluated during this period. After a year from the operation, the lid cheek distance correction was maintained in 95.7% of the cases, with stable position of the ascended malar fat pad. Postoperative edema and ecchymosis were limited. LCL is an effective, simple and rapid surgical technique, which is capable of correcting the cheek gravitational migration, reducing the lid cheek distance (LCD), maintaining the ascended stable malar fat pad for a long time with a short recovery period and minimal risk of complications. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Constrained Self-adaptive Solutions Procedures for Structure Subject to High Temperature Elastic-plastic Creep Effects

NASA Technical Reports Server (NTRS)

Padovan, J.; Tovichakchaikul, S.

1983-01-01

This paper will develop a new solution strategy which can handle elastic-plastic-creep problems in an inherently stable manner. This is achieved by introducing a new constrained time stepping algorithm which will enable the solution of creep initiated pre/postbuckling behavior where indefinite tangent stiffnesses are encountered. Due to the generality of the scheme, both monotone and cyclic loading histories can be handled. The presentation will give a thorough overview of current solution schemes and their short comings, the development of constrained time stepping algorithms as well as illustrate the results of several numerical experiments which benchmark the new procedure.

Strehl-constrained reconstruction of post-adaptive optics data and the Software Package AIRY, v. 6.1

NASA Astrophysics Data System (ADS)

Carbillet, Marcel; La Camera, Andrea; Deguignet, Jérémy; Prato, Marco; Bertero, Mario; Aristidi, Éric; Boccacci, Patrizia

2014-08-01

We first briefly present the last version of the Software Package AIRY, version 6.1, a CAOS-based tool which includes various deconvolution methods, accelerations, regularizations, super-resolution, boundary effects reduction, point-spread function extraction/extrapolation, stopping rules, and constraints in the case of iterative blind deconvolution (IBD). Then, we focus on a new formulation of our Strehl-constrained IBD, here quantitatively compared to the original formulation for simulated near-infrared data of an 8-m class telescope equipped with adaptive optics (AO), showing their equivalence. Next, we extend the application of the original method to the visible domain with simulated data of an AO-equipped 1.5-m telescope, testing also the robustness of the method with respect to the Strehl ratio estimation.

Chaos control for the output-constrained system by using adaptive dynamic surface technology and application to the brushless DC motor

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

Luo, Shaohua, E-mail: hua66com@163.com; School of Automation, Chongqing University, Chongqing 400044; Hou, Zhiwei

2015-12-15

In this paper, chaos control is proposed for the output- constrained system with uncertain control gain and time delay and is applied to the brushless DC motor. Using the dynamic surface technology, the controller overcomes the repetitive differentiation of backstepping and boundedness hypothesis of pre-determined control gain by incorporating radial basis function neural network and adaptive technology. The tangent barrier Lyapunov function is employed for time-delay chaotic system to prevent constraint violation. It is proved that the proposed control approach can guarantee asymptotically stable in the sense of uniformly ultimate boundedness without constraint violation. Finally, the effectiveness of the proposedmore » approach is demonstrated on the brushless DC motor example.« less

Wing flapping with minimum energy

NASA Technical Reports Server (NTRS)

Jones, R. T.

1980-01-01

A technique employed by Prandtl and Munk is adapted for the case of a wing in flapping motion to determine its lift distribution. The problem may be reduced to one of minimizing induced drag for a specified and periodically varying bending moment at the wing root. It is concluded that two wings in close tandem arrangement, moving in opposite phase, would eliminate the induced aerodynamic losses calculated

Naval Special Warfare Injury Prevention and Human Performance Initiative

DTIC Science & Technology

2012-06-30

that these two macronutrients fall below recommended amounts, it may impair physical performance. Dietary supplement use was reported in 73% the...a suboptimal macronutrient distribution to fuel and recover from daily hard PT. To optimize the adaptations from PT, it is recommended to increase...the injuries with 65% attributed to running and weight lifting • Higher than desirable body fat • Insufficient and inappropriate macronutrient

Non-standard neutrino interactions in the mu–tau sector

DOE PAGES

Mocioiu, Irina; Wright, Warren

2015-04-01

We discuss neutrino mass hierarchy implications arising from the effects of non-standard neutrino interactions on muon rates in high statistics atmospheric neutrino oscillation experiments like IceCube DeepCore. We concentrate on the mu–tau sector, which is presently the least constrained. It is shown that the magnitude of the effects depends strongly on the sign of the ϵμτ parameter describing this non-standard interaction. A simple analytic model is used to understand the parameter space where differences between the two signs are maximized. We discuss how this effect is partially degenerate with changing the neutrino mass hierarchy, as well as how this degeneracymore » could be lifted.« less

Lockheed L-1011 TriStar first flight to support Adaptive Performance Optimization study

NASA Technical Reports Server (NTRS)

1997-01-01

Bearing the logos of the National Aeronautics and Space Administration and Orbital Sciences Corporation, Orbital's L-1011 Tristar lifts off the Meadows Field Runway at Bakersfield, California, on its first flight May 21, 1997, in NASA's Adaptive Performance Optimization project. Developed by engineers at NASA's Dryden Flight Research Center, Edwards, California, the experiment seeks to reduce fuel consumption of large jetliners by improving the aerodynamic efficency of their wings at cruise conditions. A research computer employing a sophisticated software program adapts to changing flight conditions by commanding small movements of the L-1011's outboard ailerons to give the wings the most efficient - or optimal - airfoil. Up to a dozen research flights will be flown in the current and follow-on phases of the project over the next couple years.

An experimental study of wall adaptation and interference assessment using Cauchy integral formula

NASA Technical Reports Server (NTRS)

Murthy, A. V.

1991-01-01

This paper summarizes the results of an experimental study of combined wall adaptation and residual interference assessment using the Cauchy integral formula. The experiments were conducted on a supercritical airfoil model in the Langley 0.3-m Transonic Cryogenic Tunnel solid flexible wall test section. The ratio of model chord to test section height was about 0.7. The method worked satisfactorily in reducing the blockage interference and demonstrated the primary requirement for correcting for the blockage effects at high model incidences to correctly determine high lift characteristics. The studies show that the method has potential for reducing the residual interference to considerably low levels. However, corrections to blockage and upwash velocities gradients may still be required for the final adapted wall shapes.

Toward Adaptive X-Ray Telescopes

NASA Technical Reports Server (NTRS)

O'Dell, Stephen L.; Atkins, Carolyn; Button, Tim W.; Cotroneo, Vincenzo; Davis, William N.; Doel, Peer; Feldman, Charlotte H.; Freeman, Mark D.; Gubarev, Mikhail V.; Kolodziejczak, Jeffrey J.;

Elevated waterproof access floor system and method of making the same

NASA Technical Reports Server (NTRS)

Cohen, Marc M. (Inventor)

1987-01-01

An elevated waterproof access floor system having subfloor channels or compartments for power lines, gas lines or the like is adapted such that it can be opened and subsequently resealed without destroying the waterproofing and without destroying its aesthetic appearance. A multiplicity of tiles are supported on a support grid, and a flooring sheet is supported on the tiles. Attachment means are provided to prevent lateral but not vertical movement of the flooring sheet with respect to the tiles so that the flooring sheet can be lifted off the tiles, but when the flooring sheet is supported on the tiles, no lateral slipping will occur. The flooring sheet is made of a heat resealable material, so that it can be cut away in sections, and the tiles therebelow lifted off, to provide access to subfloor compartments.

KSC-97PC1109

NASA Image and Video Library

1997-07-22

Flight mechanics from NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif., inspect their work after mating the Cassini spacecraft to its launch vehicle adapter in KSC’s Payload Hazardous Servicing Facility. The adapter will later be mated to a Titan IV/Centaur expendable launch vehicle that will lift Cassini into space. Scheduled for launch in October, the Cassini mission, a joint US-European four-year orbital surveillance of Saturn's atmosphere and magnetosphere, its rings, and its moons, seeks insight into the origins and evolution of the early solar system. It will take seven years for the spacecraft to reach Saturn. JPL is managing the Cassini project for NASA

A quantitative method for evaluating inferior glenohumeral joint stiffness using ultrasonography.

PubMed

Tsai, Wen-Wei; Lee, Ming-Yih; Yeh, Wen-Lin; Cheng, Shih-Chung; Soon, Kok-Soon; Lei, Kin Fong; Lin, Wen-Yen

2013-02-01

Subluxation of the affected shoulder in post-stroke patients is associated with nerve disorders and muscle fatigue. Clinicians must be able to accurately and reliably measure inferior glenohumeral subluxation in patients to provide appropriate treatment. However, quantitative methods for evaluating the laxity and stiffness of the glenohumeral joint (GHJ) are still being developed. The aim of this study was to develop a new protocol for evaluating the laxity and stiffness of the inferior GHJ using ultrasonography under optimal testing conditions and to investigate changes in the GHJ from a commercially available humerus brace and shoulder brace. Multistage inferior displacement forces were applied to create a glide between the most cephalad point on the visible anterosuperior surface of the humeral head and coracoid process in seven healthy volunteers. GHJ stiffness was defined as the slope of the linear regression line between the glides and different testing loads. The testing conditions were defined by different test loading mechanisms (n=2), shoulder constraining conditions (n=2), and loading modes (n=4). The optimal testing condition was defined as the condition with the least residual variance of measured laxity to the calculated stiffness under different testing loads. A paired t-test was used to compare the laxity and stiffness of the inferior GHJ using different braces. No significant difference was identified between the two test loading mechanisms (t=0.218, p=0.831) and two shoulder constraining conditions (t=-0.235, p=0.818). We concluded that ultrasonographic laxity measurements performed using a pulley set loading mechanism was as reliable as direct loading. Additionally, constraining the unloaded shoulder was proposed due to the lower mean residual variance value. Moreover, pulling the elbow downward with loading on the upper arm was suggested, as pulling the elbow downward with the elbow flexed and loading on the forearm may overestimate stiffness and pain in the inferior GHJ at the loading point due to friction between the wide belt and skin. Furthermore, subjects wearing a humerus brace with a belt, which creates the effect of lifting the humerus toward the acromion, had greater GHJ stiffness compared to subjects wearing a shoulder brace without a belt to lift the humerus under the proposed testing conditions. This study provides experimental evidence that shoulder braces may reduce GHJ laxity under an external load, implying that the use of a humeral brace can prevent subluxation in post-stroke patients. The resulting optimal testing conditions for measuring the laxity and stiffness of the GHJ is to constrain the unloaded shoulder and bend the loaded arm at the elbow with loading on the upper arm using a pulley system. Copyright © 2011 IPEM. Published by Elsevier Ltd. All rights reserved.

Application of reversible denoising and lifting steps with step skipping to color space transforms for improved lossless compression

NASA Astrophysics Data System (ADS)

Starosolski, Roman

2016-07-01

Reversible denoising and lifting steps (RDLS) are lifting steps integrated with denoising filters in such a way that, despite the inherently irreversible nature of denoising, they are perfectly reversible. We investigated the application of RDLS to reversible color space transforms: RCT, YCoCg-R, RDgDb, and LDgEb. In order to improve RDLS effects, we propose a heuristic for image-adaptive denoising filter selection, a fast estimator of the compressed image bitrate, and a special filter that may result in skipping of the steps. We analyzed the properties of the presented methods, paying special attention to their usefulness from a practical standpoint. For a diverse image test-set and lossless JPEG-LS, JPEG 2000, and JPEG XR algorithms, RDLS improves the bitrates of all the examined transforms. The most interesting results were obtained for an estimation-based heuristic filter selection out of a set of seven filters; the cost of this variant was similar to or lower than the transform cost, and it improved the average lossless JPEG 2000 bitrates by 2.65% for RDgDb and by over 1% for other transforms; bitrates of certain images were improved to a significantly greater extent.

Investigation of gliding flight by flying fish

NASA Astrophysics Data System (ADS)

Park, Hyungmin; Jeon, Woo-Pyung; Choi, Haecheon

2006-11-01

The most successful flight capability of fish is observed in the flying fish. Furthermore, despite the difference between two medium (air and water), the flying fish is well evolved to have an excellent gliding performance as well as fast swimming capability. In this study, flying fish's morphological adaptation to gliding flight is experimentally investigated using dry-mounted darkedged-wing flying fish, Cypselurus Hiraii. Specifically, we examine the effects of the pectoral and pelvic fins on the aerodynamic performance considering (i) both pectoral and pelvic fins, (ii) pectoral fins only, and (iii) body only with both fins folded. Varying the attack angle, we measure the lift, drag and pitching moment at the free-stream velocity of 12m/s for each case. Case (i) has higher lift-to-drag ratio (i.e. longer gliding distance) and more enhanced longitudinal static stability than case (ii). However, the lift coefficient is smaller for case (i) than for case (ii), indicating that the pelvic fins are not so beneficial for wing loading. The gliding performance of flying fish is compared with those of other fliers and is found to be similar to those of insects such as the butterfly and fruitfly.

Imaging of Nuclear Weapon Trainers

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

Schwellenbach, David

2017-12-06

The Configurable Muon Tracker (CMT) is an adaptation of the existing drift tube detector commercially available from Decision Sciences International Corporation (DSIC). NSTec engineered the CMT around commercially available drift tube assemblies to make a detector that is more versatile than previous drift tube assemblies. The CMT became operational in February 2013. Traditionally, cosmic-ray muon trackers rely on near-vertical trajectory muons for imaging. Since there are scenarios where imaging using vertical trajectory muons is not practical, NSTec designed the CMT specifically for quick configurability to track muons from any trajectory. The CMT was originally designed to be changed from verticalmore » imaging mode to horizontal imaging mode in a few hours with access to a crane or other lifting equipment. In FY14, locations for imaging weapon trainers and SNM were identified and it was determined that lifting equipment would not typically be available in experimental areas. The CMT was further modified and a portable lifting system was developed to allow reconfiguration of the CMT without access to lifting equipment at the facility. This system was first deployed at Los Alamos National Laboratory’s W-division, where several trainers were imaged in both horizontal and vertical modes. Real-time images have been compared in both modes showing that imaging can be done in both modes with the expected longer integration time for horizontal mode. Further imaging and post processing of the data is expected to continue into early FY15.« less

An embodied biologically constrained model of foraging: from classical and operant conditioning to adaptive real-world behavior in DAC-X.

PubMed

Maffei, Giovanni; Santos-Pata, Diogo; Marcos, Encarni; Sánchez-Fibla, Marti; Verschure, Paul F M J

2015-12-01

Animals successfully forage within new environments by learning, simulating and adapting to their surroundings. The functions behind such goal-oriented behavior can be decomposed into 5 top-level objectives: 'how', 'why', 'what', 'where', 'when' (H4W). The paradigms of classical and operant conditioning describe some of the behavioral aspects found in foraging. However, it remains unclear how the organization of their underlying neural principles account for these complex behaviors. We address this problem from the perspective of the Distributed Adaptive Control theory of mind and brain (DAC) that interprets these two paradigms as expressing properties of core functional subsystems of a layered architecture. In particular, we propose DAC-X, a novel cognitive architecture that unifies the theoretical principles of DAC with biologically constrained computational models of several areas of the mammalian brain. DAC-X supports complex foraging strategies through the progressive acquisition, retention and expression of task-dependent information and associated shaping of action, from exploration to goal-oriented deliberation. We benchmark DAC-X using a robot-based hoarding task including the main perceptual and cognitive aspects of animal foraging. We show that efficient goal-oriented behavior results from the interaction of parallel learning mechanisms accounting for motor adaptation, spatial encoding and decision-making. Together, our results suggest that the H4W problem can be solved by DAC-X building on the insights from the study of classical and operant conditioning. Finally, we discuss the advantages and limitations of the proposed biologically constrained and embodied approach towards the study of cognition and the relation of DAC-X to other cognitive architectures. Copyright © 2015 Elsevier Ltd. All rights reserved.

Multidisciplinary design optimization for sonic boom mitigation

NASA Astrophysics Data System (ADS)

Ozcer, Isik A.

Automated, parallelized, time-efficient surface definition and grid generation and flow simulation methods are developed for sharp and accurate sonic boom signal computation in three dimensions in the near and mid-field of an aircraft using Euler/Full-Potential unstructured/structured computational fluid dynamics. The full-potential mid-field sonic boom prediction code is an accurate and efficient solver featuring automated grid generation, grid adaptation and shock fitting, and parallel processing. This program quickly marches the solution using a single nonlinear equation for large distances that cannot be covered with Euler solvers due to large memory and long computational time requirements. The solver takes into account variations in temperature and pressure with altitude. The far-field signal prediction is handled using the classical linear Thomas Waveform Parameter Method where the switching altitude from the nonlinear to linear prediction is determined by convergence of the ground signal pressure impulse value. This altitude is determined as r/L ≈ 10 from the source for a simple lifting wing, and r/L ≈ 40 for a real complex aircraft. Unstructured grid adaptation and shock fitting methodology developed for the near-field analysis employs an Hessian based anisotropic grid adaptation based on error equidistribution. A special field scalar is formulated to be used in the computation of the Hessian based error metric which enhances significantly the adaptation scheme for shocks. The entire cross-flow of a complex aircraft is resolved with high fidelity using only 500,000 grid nodes after only about 10 solution/adaptation cycles. Shock fitting is accomplished using Roe's Flux-Difference Splitting scheme which is an approximate Riemann type solver and by proper alignment of the cell faces with respect to shock surfaces. Simple to complex real aircraft geometries are handled with no user-interference required making the simulation methods suitable tools for product design. The simulation tools are used to optimize three geometries for sonic boom mitigation. The first is a simple axisymmetric shape to be used as a generic nose component, the second is a delta wing with lift, and the third is a real aircraft with nose and wing optimization. The objectives are to minimize the pressure impulse or the peak pressure in the sonic boom signal, while keeping the drag penalty under feasible limits. The design parameters for the meridian profile of the nose shape are the lengths and the half-cone angles of the linear segments that make up the profile. The design parameters for the lifting wing are the dihedral angle, angle of attack, non-linear span-wise twist and camber distribution. The test-bed aircraft is the modified F-5E aircraft built by Northrop Grumman, designated the Shaped Sonic Boom Demonstrator. This aircraft is fitted with an optimized axisymmetric nose, and the wings are optimized to demonstrate optimization for sonic boom mitigation for a real aircraft. The final results predict 42% reduction in bow shock strength, 17% reduction in peak Deltap, 22% reduction in pressure impulse, 10% reduction in foot print size, 24% reduction in inviscid drag, and no loss in lift for the optimized aircraft. Optimization is carried out using response surface methodology, and the design matrices are determined using standard DoE techniques for quadratic response modeling.

Constraining planetary atmospheric density: application of heuristic search algorithms to aerodynamic modeling of impact ejecta trajectories

NASA Astrophysics Data System (ADS)

Liu, Z. Y. C.; Shirzaei, M.

2015-12-01

Impact craters on the terrestrial planets are typically surrounded by a continuous ejecta blanket that the initial emplacement is via ballistic sedimentation. Following an impact event, a significant volume of material is ejected and falling debris surrounds the crater. Aerodynamics rule governs the flight path and determines the spatial distribution of these ejecta. Thus, for the planets with atmosphere, the preserved ejecta deposit directly recorded the interaction of ejecta and atmosphere at the time of impact. In this study, we develop a new framework to establish links between distribution of the ejecta, age of the impact and the properties of local atmosphere. Given the radial distance of the continuous ejecta extent from crater, an inverse aerodynamic modeling approach is employed to estimate the local atmospheric drags and density as well as the lift forces at the time of impact. Based on earlier studies, we incorporate reasonable value ranges for ejection angle, initial velocity, aerodynamic drag, and lift in the model. In order to solve the trajectory differential equations, obtain the best estimate of atmospheric density, and the associated uncertainties, genetic algorithm is applied. The method is validated using synthetic data sets as well as detailed maps of impact ejecta associated with five fresh martian and two lunar impact craters, with diameter of 20-50 m, 10-20 m, respectively. The estimated air density for martian carters range 0.014-0.028 kg/m3, consistent with the recent surface atmospheric density measurement of 0.015-0.020 kg/m3. This constancy indicates the robustness of the presented methodology. In the following, the inversion results for the lunar craters yield air density of 0.003-0.008 kg/m3, which suggest the inversion results are accurate to the second decimal place. This framework will be applied to older martian craters with preserved ejecta blankets, which expect to constrain the long-term evolution of martian atmosphere.

Offsetting Gravity

NASA Technical Reports Server (NTRS)

1976-01-01

The Coastal Center and the NASA Biomedical Team are working together to adapt a suspension device that simulates weightlessness. Attempts to approximate weightlessness have led astronauts underwater and into harnesses that suspend all or part of their weight. One such device, built at Langley Research Center, is being transferred to rehabilitation work. It can help a person walk and re-learn muscular coordination following a stroke. Hospitals could use it to lift handicapped persons.

Measurements and performance prediction of an adaptive wing micro air vehicle

NASA Astrophysics Data System (ADS)

Shkarayev, Sergey V.; Jouse, Wayne C.; Null, William R.; Wagner, Matthew G.

2003-08-01

The mission space requirements imposed on the design of micro air vehicles (MAVs) typically consist of several distinct flight segments that generally conflict: the transit phases of flight require high speeds, while the loiter/surveillance phase requires lower flight velocities. Maximum efficiency must be sought in order to prolong battery life and aircraft endurance. The adaptive wing MAV developed at the University of Arizona features a thin, deformable flying wing with an efficient rudder-elevator control system. The wing camber is varied to accommodate different flight speeds while maintaining a constant total lift at a relatively low angle of attack. A new airfoil was developed from the Selig 5010 that features a small negative pitching moment for pitch stability. Wind tunnel tests were performed and stall angles and best lift-to-drag ratios were analyzed from the data. The wind tunnel data was used in a performance analysis in order to determine the flight speeds and throttle settings for maximum endurance at each camber, as well as the MAV's theoretical minimum and maximum flight speeds. The effectiveness of camber change on flight speed and endurance was examined with promising results; flight speed could be reduced by 25% by increasing the camber from 3 to 9% without any increase in power consumption.

Guidance and Control Architecture Design and Demonstration for Low Ballistic Coefficient Atmospheric Entry

NASA Technical Reports Server (NTRS)

Swei, Sean

2014-01-01

We propose to develop a robust guidance and control system for the ADEPT (Adaptable Deployable Entry and Placement Technology) entry vehicle. A control-centric model of ADEPT will be developed to quantify the performance of candidate guidance and control architectures for both aerocapture and precision landing missions. The evaluation will be based on recent breakthroughs in constrained controllability/reachability analysis of control systems and constrained-based energy-minimum trajectory optimization for guidance development operating in complex environments.

Head shape evolution in Tropidurinae lizards: does locomotion constrain diet?

PubMed

Kohlsdorf, T; Grizante, M B; Navas, C A; Herrel, A

2008-05-01

Different components of complex integrated systems may be specialized for different functions, and thus the selective pressures acting on the system as a whole may be conflicting and can ultimately constrain organismal performance and evolution. The vertebrate cranial system is one of the most striking examples of a complex system with several possible functions, being associated to activities as different as locomotion, prey capture, display and defensive behaviours. Therefore, selective pressures on the cranial system as a whole are possibly complex and may be conflicting. The present study focuses on the influence of potentially conflicting selective pressures (diet vs. locomotion) on the evolution of head shape in Tropidurinae lizards. For example, the expected adaptations leading to flat heads and bodies in species living on vertical structures may conflict with the need for improved bite performance associated with the inclusion of hard or tough prey into the diet, a common phenomenon in Tropidurinae lizards. Body size and six variables describing head shape were quantified in preserved specimens of 23 species, and information on diet and substrate usage was obtained from the literature. No phylogenetic signal was observed in the morphological data at any branch length tested, suggesting adaptive evolution of head shape in Tropidurinae. This pattern was confirmed by both factor analysis and independent contrast analysis, which suggested adaptive co-variation between the head shape and the inclusion of hard prey into the diet. In contrast to our expectations, habitat use did not constrain or drive head shape evolution in the group.

Can Skateboarding Save the Planet? A Curricular Unit on Global Climate Change Developed Through the NASA LIFT-OFF Program

NASA Astrophysics Data System (ADS)

Pruett, L. E.; Burrell, S.; Chidester, C.; Metzger, E. P.

2010-12-01

The inclusion of global climate change education in California public high schools is constrained by several factors, including the planning time needed to effectively correlate state content standards to the multidisciplinary science of climate change, the lack of time in the curriculum, and budget constraints that limit resources for teachers. Recent efforts by the NASA LIFT-OFF program to support classroom teachers in the development of inquiry-based curricular materials have helped to alleviate many of these burdens. NASA LIFT-OFF is funded by a grant to the Alameda County Office of Education and involves a partnership between the Alameda, Santa Clara, and Los Angeles county offices of education and science faculty at California State University (CSU) East Bay, San Jose State University (SJSU), and Cal Poly Pomona. LIFT-OFF goals are to improve high school science teachers’ content knowledge through interactions with scientists from the CSU campuses, NASA, and the SETI Institute and to enhance their ability to plan and implement high-quality science inquiry in their classrooms. LIFT-OFF teachers at the three CSU campuses are developing instructional cases that use NASA resources and research-based pedagogical practices to explore engaging real-world questions. We participated in SJSU’s 2010 LIFT-OFF summer institute and worked as a team to develop a 12-day unit for high school students that focuses on the science behind global climate change. In addition to delivering science content, the unit engages students in critical thinking and evaluation. Students generate, access and interpret data, and use the knowledge gained to make small lifestyle changes that aid in the reduction of their greenhouse gas emissions. Not only does this unit of study empower students to make science-based decisions, it also incorporates diverse learning strategies, such as the use of visuals aids, language acquisition techniques to improve literacy, formative assessments and daily hands-on demonstrations and lab activities. Our unit begins with an introduction to greenhouse gases and the greenhouse effect. It progresses with several lessons focused on the carbon cycle and its role in global climate, including the anthropogenic contribution to atmospheric carbon. This unit includes a longitudinal analysis of atmospheric CO2 concentrations, how they have changed over time and one method for studying historical levels (ice cores). Earth’s CO2 levels are then compared to that of our celestial neighbors, Mars and Venus. Students will use this data to make predictions about the nature of life on Earth given higher CO2 levels. We present lessons meant to give students time to reflect upon their daily lives and find small ways to help reduce their carbon footprint. They will be presented with information on alternative forms of energy and be given a summative assessment. Once refined, this and all NASA LIFT-OFF instructional cases will made available online for use by any interested teacher. For more information go to http://nasaliftoff.merlot.org/.

Adapting to the Effects of Climate Change on Inuit Health

PubMed Central

Ford, James D.; Willox, Ashlee Cunsolo; Chatwood, Susan; Furgal, Christopher; Harper, Sherilee; Mauro, Ian; Pearce, Tristan

2014-01-01

Climate change will have far-reaching implications for Inuit health. Focusing on adaptation offers a proactive approach for managing climate-related health risks—one that views Inuit populations as active agents in planning and responding at household, community, and regional levels. Adaptation can direct attention to the root causes of climate vulnerability and emphasize the importance of traditional knowledge regarding environmental change and adaptive strategies. An evidence base on adaptation options and processes for Inuit regions is currently lacking, however, thus constraining climate policy development. In this article, we tackled this deficit, drawing upon our understanding of the determinants of health vulnerability to climate change in Canada to propose key considerations for adaptation decision-making in an Inuit context. PMID:24754615

Adapting to the effects of climate change on Inuit health.

PubMed

Ford, James D; Willox, Ashlee Cunsolo; Chatwood, Susan; Furgal, Christopher; Harper, Sherilee; Mauro, Ian; Pearce, Tristan

2014-06-01

Climate change will have far-reaching implications for Inuit health. Focusing on adaptation offers a proactive approach for managing climate-related health risks-one that views Inuit populations as active agents in planning and responding at household, community, and regional levels. Adaptation can direct attention to the root causes of climate vulnerability and emphasize the importance of traditional knowledge regarding environmental change and adaptive strategies. An evidence base on adaptation options and processes for Inuit regions is currently lacking, however, thus constraining climate policy development. In this article, we tackled this deficit, drawing upon our understanding of the determinants of health vulnerability to climate change in Canada to propose key considerations for adaptation decision-making in an Inuit context.

Apparatus for adapting an end effector device remotely controlled manipulator arm

NASA Technical Reports Server (NTRS)

Clark, K. H. (Inventor)

1985-01-01

Apparatus for adapting a general purpose and effector device to a special purpose and effector is disclosed which includes an adapter bracket assembly which provides a mechanical and electrical interface between the end effector devices. The adapter bracket assembly includes an adapter connector post which interlocks with a diamond shaped gripping channel formed in closed jaws of the general purpose end effector. The angularly intersecting surfaces of the connector post and gripping channel prevent any relative movement there between. Containment webs constrain the outer finger plates of the general purpose jaws to prevent pitch motion. Electrical interface is provided by conical, self aligning electrical connector components carried by respective ones of said end effectors.

Neural Representations of Sensorimotor Memory- and Digit Position-Based Load Force Adjustments Before the Onset of Dexterous Object Manipulation.

PubMed

Marneweck, Michelle; Barany, Deborah A; Santello, Marco; Grafton, Scott T

2018-05-16

Anticipatory load forces for dexterous object manipulation in humans are modulated based on visual object property cues, sensorimotor memories of previous experiences with the object, and, when digit positioning varies from trial to trial, the integrating of this sensed variability with force modulation. Studies of the neural representations encoding these anticipatory mechanisms have not considered these mechanisms separately from each other or from feedback mechanisms emerging after lift onset. Here, representational similarity analyses of fMRI data were used to identify neural representations of sensorimotor memories and the sensing and integration of digit position. Cortical activity and movement kinematics were measured as 20 human subjects (11 women) minimized tilt of a symmetrically shaped object with a concealed asymmetric center of mass (CoM, left and right sided). This task required generating compensatory torques in opposite directions, which, without helpful visual CoM cues, relied primarily on sensorimotor memories of the same object and CoM. Digit position was constrained or unconstrained, the latter of which required modulating forces beyond what can be recalled from sensorimotor memories to compensate for digit position variability. Ventral premotor (PMv), somatosensory, and cerebellar lobule regions (CrusII, VIIIa) were sensitive to anticipatory behaviors that reflect sensorimotor memory content, as shown by larger voxel pattern differences for unmatched than matched CoM conditions. Cerebellar lobule I-IV, Broca area 44, and PMv showed greater voxel pattern differences for unconstrained than constrained grasping, which suggests their sensitivity to monitor the online coincidence of planned and actual digit positions and correct for a mismatch by force modulation. SIGNIFICANCE STATEMENT To pick up a water glass without slipping, tipping, or spilling requires anticipatory planning of fingertip load forces before the lift commences. This anticipation relies on object visual properties (e.g., mass/mass distribution), sensorimotor memories built from previous experiences (especially when object properties cannot be inferred visually), and online sensing of where the digits are positioned. There is limited understanding of how the brain represents each of these anticipatory mechanisms. We used fMRI measures of regional brain patterns and digit position kinematics before lift onset of an object with nonsalient visual cues specifically to isolate sensorimotor memories and integration of sensed digit position with force modulation. In doing so, we localized neural representations encoding these anticipatory mechanisms for dexterous object manipulation. Copyright © 2018 the authors 0270-6474/18/384724-14$15.00/0.

Structural integrated sensor and actuator systems for active flow control

NASA Astrophysics Data System (ADS)

Behr, Christian; Schwerter, Martin; Leester-Schädel, Monika; Wierach, Peter; Dietzel, Andreas; Sinapius, Michael

2016-04-01

An adaptive flow separation control system is designed and implemented as an essential part of a novel high-lift device for future aircraft. The system consists of MEMS pressure sensors to determine the flow conditions and adaptive lips to regulate the mass flow and the velocity of a wall near stream over the internally blown Coanda flap. By the oscillating lip the mass flow in the blowing slot changes dynamically, consequently the momentum exchange of the boundary layer over a high lift flap required mass flow can be reduced. These new compact and highly integrated systems provide a real-time monitoring and manipulation of the flow conditions. In this context the integration of pressure sensors into flow sensing airfoils of composite material is investigated. Mechanical and electrical properties of the integrated sensors are investigated under mechanical loads during tensile tests. The sensors contain a reference pressure chamber isolated to the ambient by a deformable membrane with integrated piezoresistors connected as a Wheatstone bridge, which outputs voltage signals depending on the ambient pressure. The composite material in which the sensors are embedded consists of 22 individual layers of unidirectional glass fiber reinforced plastic (GFRP) prepreg. The results of the experiments are used for adapting the design of the sensors and the layout of the laminate to ensure an optimized flux of force in highly loaded structures primarily for future aeronautical applications. It can be shown that the pressure sensor withstands the embedding process into fiber composites with full functional capability and predictable behavior under stress.

Spanwise morphing trailing edge on a finite wing

NASA Astrophysics Data System (ADS)

Pankonien, Alexander M.; Inman, Daniel J.

2015-04-01

Unmanned Aerial Vehicles are prime targets for morphing implementation as they must adapt to large changes in flight conditions associated with locally varying wind or large changes in mass associated with payload delivery. The Spanwise Morphing Trailing Edge concept locally varies the trailing edge camber of a wing or control surface, functioning as a modular replacement for conventional ailerons without altering the spar box. Utilizing alternating active sections of Macro Fiber Composites (MFCs) driving internal compliant mechanisms and inactive sections of elastomeric honeycombs, the SMTE concept eliminates geometric discontinuities associated with shape change, increasing aerodynamic performance. Previous work investigated a representative section of the SMTE concept and investigated the effect of various skin designs on actuation authority. The current work experimentally evaluates the aerodynamic gains for the SMTE concept for a representative finite wing as compared with a conventional, articulated wing. The comparative performance for both wings is evaluated by measuring the drag penalty associated with achieving a design lift coefficient from an off-design angle of attack. To reduce experimental complexity, optimal control configurations are predicted with lifting line theory and experimentally measured control derivatives. Evaluated over a range of off-design flight conditions, this metric captures the comparative capability of both concepts to adapt or "morph" to changes in flight conditions. Even with this simplistic model, the SMTE concept is shown to reduce the drag penalty due to adaptation up to 20% at off-design conditions, justifying the increase in mass and complexity and motivating concepts capable of larger displacement ranges, higher fidelity modelling, and condition-sensing control.

Attentive Reading With Constrained Summarization Adapted to Address Written Discourse in People With Mild Aphasia.

PubMed

Obermeyer, Jessica A; Edmonds, Lisa A

2018-03-01

The purpose of this study was to examine the preliminary efficacy of Attentive Reading and Constrained Summarization-Written (ARCS-W) in people with mild aphasia. ARCS-W adapts an existing treatment, ARCS (Rogalski & Edmonds, 2008), to address discourse level writing in mild aphasia. ARCS-W focuses on the cognitive and linguistic skills required for discourse production. This study was a within-subject pre-postdesign. Three people with mild aphasia participated. ARCS-W integrates attentive reading or listening with constrained summarization of discourse level material in spoken and written modalities. Outcomes included macro- (main concepts) and microlinguistic (correct information units, complete utterances) discourse measures, confrontation naming, aphasia severity, and functional communication. All 3 participants demonstrated some generalization to untrained spoken and written discourse at the word, sentence, and text levels. Reduced aphasia severity and/or increased functional communication and confrontation naming were also observed in some participants. The findings of this study provide preliminary evidence of the efficacy of ARCS-W to improve spoken and written discourse in mild aphasia. Different generalization patterns suggest different mechanisms of improvement. Further research and replication are required to better understand how ARCS-W can impact discourse abilities.

Advancements in adaptive aerodynamic technologies for airfoils and wings

NASA Astrophysics Data System (ADS)

Jepson, Jeffrey Keith

Although aircraft operate over a wide range of flight conditions, current fixed-geometry aircraft are optimized for only a few of these conditions. By altering the shape of the aircraft, adaptive aerodynamics can be used to increase the safety and performance of an aircraft by tailoring the aircraft for multiple flight conditions. Of the various shape adaptation concepts currently being studied, the use of multiple trailing-edge flaps along the span of a wing offers a relatively high possibility of being incorporated on aircraft in the near future. Multiple trailing-edge flaps allow for effective spanwise camber adaptation with resulting drag benefits over a large speed range and load alleviation at high-g conditions. The research presented in this dissertation focuses on the development of this concept of using trailing-edge flaps to tailor an aircraft for multiple flight conditions. One of the major tasks involved in implementing trailing-edge flaps is in designing the airfoil to incorporate the flap. The first part of this dissertation presents a design formulation that incorporates aircraft performance considerations in the inverse design of low-speed laminar-flow adaptive airfoils with trailing-edge cruise flaps. The benefit of using adaptive airfoils is that the size of the low-drag region of the drag polar can be effectively increased without increasing the maximum thickness of the airfoil. Two aircraft performance parameters are considered: level-flight maximum speed and maximum range. It is shown that the lift coefficients for the lower and upper corners of the airfoil low-drag range can be appropriately adjusted to tailor the airfoil for these two aircraft performance parameters. The design problem is posed as a part of a multidimensional Newton iteration in an existing conformal-mapping based inverse design code, PROFOIL. This formulation automatically adjusts the lift coefficients for the corners of the low-drag range for a given flap deflection as required for the airfoil-aircraft matching. Examples are presented to illustrate the flapped-airfoil design approach for a general aviation aircraft and the results are validated by comparison with results from post-design aircraft performance computations. Once the airfoil is designed to incorporate a TE flap, it is important to determine the most suitable flap angles along the wing for different flight conditions. The second part of this dissertation presents a method for determining the optimum flap angles to minimize drag based on pressures measured at select locations on the wing. Computational flow simulations using a panel method are used "in the loop" for demonstrating closed-loop control of the flaps. Examples in the paper show that the control algorithm is successful in correctly adapting the wing to achieve the target lift distributions for minimizing induced drag while adjusting the wing angle of attack for operation of the wing in the drag bucket. It is shown that the "sense-and-adapt" approach developed is capable of handling varying and unpredictable inflow conditions. Such a capability could be useful in adapting long-span flexible wings that may experience significant and unknown atmospheric inflow variations along the span. To further develop the "sense-and-adapt" approach, the method was tested experimentally in the third part of the research. The goal of the testing was to see if the same results found computationally can be obtained experimentally. The North Carolina State University subsonic wind tunnel was used for the wind tunnel tests. Results from the testing showed that the "sense-and-adapt" approach has the same performance experimentally as it did computationally. The research presented in this dissertation is a stepping stone towards further development of the concept, which includes modeling the system in the Simulink environment and flight experiments using uninhabited aerial vehicles.

Aerodynamic evaluation of wing shape and wing orientation in four butterfly species using numerical simulations and a low-speed wind tunnel, and its implications for the design of flying micro-robots.

PubMed

Ortega Ancel, Alejandro; Eastwood, Rodney; Vogt, Daniel; Ithier, Carter; Smith, Michael; Wood, Rob; Kovač, Mirko

2017-02-06

Many insects are well adapted to long-distance migration despite the larger energetic costs of flight for small body sizes. To optimize wing design for next-generation flying micro-robots, we analyse butterfly wing shapes and wing orientations at full scale using numerical simulations and in a low-speed wind tunnel at 2, 3.5 and 5 m s -1 . The results indicate that wing orientations which maximize wing span lead to the highest glide performance, with lift to drag ratios up to 6.28, while spreading the fore-wings forward can increase the maximum lift produced and thus improve versatility. We discuss the implications for flying micro-robots and how the results assist in understanding the behaviour of the butterfly species tested.

On lifting the fog of war in the battle on heart disease: Star Wars technology in pursuit of a seamless integration strategy.

PubMed

Espinosa, J A; Kosnik, L K; Kraitsik, M; Dillow, J C

1997-01-01

In our efforts to reduce cardiac morbidity and mortality we often use terms such as the "battle" or "war" on heart disease. If we believe efforts to reduce cardiac disease are the moral equivalent of war, then perhaps we should explore ways that military strategic and tactical metaphors can be applied through technology to the cardiac battle. In this article we explore three major areas for technological advancement: adaptation of the strategies of outcomes management and evidence-based medicine, computer simulation and animation efforts to create horizontal and vertical integration of strategic efforts, and use of interactive multimedia in "recruiting an army" through community empowerment. The overall goal is to find ways to lift "the fog of war" in the battle on heart disease, in order to further the integration of our various efforts.

Interset stretching does not influence the kinematic profile of consecutive bench-press sets.

PubMed

García-López, David; Izquierdo, Mikel; Rodríguez, Sergio; González-Calvo, Gustavo; Sainz, Nuria; Abadía, Olaia; Herrero, Azael J

2010-05-01

This study was undertaken to examine the role of interset stretching on the time course of acceleration portion AP and mean velocity profile during the concentric phase of 2 bench-press sets with a submaximal load (60% of the 1 repetition maximum). Twenty-five college students carried out, in 3 different days, 2 consecutive bench-press sets leading to failure, performing between sets static stretching, ballistic stretching, or no stretching. Acceleration portion and lifting velocity patterns of the concentric phase were not altered during the second set, regardless of the stretching treatment performed. However, when velocity was expressed in absolute terms, static stretching reduced significantly (p <0.05) the average lifting velocity during the second set compared to the first one. Therefore, if maintenance of a high absolute velocity over consecutive sets is important for training-related adaptations, static stretching should be avoided or replaced by ballistic stretching.

Aerodynamic evaluation of wing shape and wing orientation in four butterfly species using numerical simulations and a low-speed wind tunnel, and its implications for the design of flying micro-robots

PubMed Central

Eastwood, Rodney; Vogt, Daniel; Ithier, Carter; Smith, Michael; Wood, Rob; Kovač, Mirko

2017-01-01

Many insects are well adapted to long-distance migration despite the larger energetic costs of flight for small body sizes. To optimize wing design for next-generation flying micro-robots, we analyse butterfly wing shapes and wing orientations at full scale using numerical simulations and in a low-speed wind tunnel at 2, 3.5 and 5 m s−1. The results indicate that wing orientations which maximize wing span lead to the highest glide performance, with lift to drag ratios up to 6.28, while spreading the fore-wings forward can increase the maximum lift produced and thus improve versatility. We discuss the implications for flying micro-robots and how the results assist in understanding the behaviour of the butterfly species tested. PMID:28163879

Multiplatform Mission Planning and Operations Simulation Environment for Adaptive Remote Sensors

NASA Astrophysics Data System (ADS)

Smith, G.; Ball, C.; O'Brien, A.; Johnson, J. T.

2017-12-01

We report on the design and development of mission simulator libraries to support the emerging field of adaptive remote sensors. We will outline the current state of the art in adaptive sensing, provide analysis of how the current approach to performing observing system simulation experiments (OSSEs) must be changed to enable adaptive sensors for remote sensing, and present an architecture to enable their inclusion in future OSSEs.The growing potential of sensors capable of real-time adaptation of their operational parameters calls for a new class of mission planning and simulation tools. Existing simulation tools used in OSSEs assume a fixed set of sensor parameters in terms of observation geometry, frequencies used, resolution, or observation time, which allows simplifications to be made in the simulation and allows sensor observation errors to be characterized a priori. Adaptive sensors may vary these parameters depending on the details of the scene observed, so that sensor performance is not simple to model without conducting OSSE simulations that include sensor adaptation in response to varying observational environment. Adaptive sensors are of significance to resource-constrained, small satellite platforms because they enable the management of power and data volumes while providing methods for multiple sensors to collaborate.The new class of OSSEs required to utilize adaptive sensors located on multiple platforms must answer the question: If the physical act of sensing has a cost, how does the system determine if the science value of a measurement is worth the cost and how should that cost be shared among the collaborating sensors?Here we propose to answer this question using an architecture structured around three modules: ADAPT, MANAGE and COLLABORATE. The ADAPT module is a set of routines to facilitate modeling of adaptive sensors, the MANAGE module will implement a set of routines to facilitate simulations of sensor resource management when power and data volume are constrained, and the COLLABORATE module will support simulations of coordination among multiple platforms with adaptive sensors. When used together these modules will for a simulation OSSEs that can enable both the design of adaptive algorithms to support remote sensing and the prediction of the sensor performance.

Non-Kolmogorovian Approach to the Context-Dependent Systems Breaking the Classical Probability Law

NASA Astrophysics Data System (ADS)

Asano, Masanari; Basieva, Irina; Khrennikov, Andrei; Ohya, Masanori; Yamato, Ichiro

2013-07-01

There exist several phenomena breaking the classical probability laws. The systems related to such phenomena are context-dependent, so that they are adaptive to other systems. In this paper, we present a new mathematical formalism to compute the joint probability distribution for two event-systems by using concepts of the adaptive dynamics and quantum information theory, e.g., quantum channels and liftings. In physics the basic example of the context-dependent phenomena is the famous double-slit experiment. Recently similar examples have been found in biological and psychological sciences. Our approach is an extension of traditional quantum probability theory, and it is general enough to describe aforementioned contextual phenomena outside of quantum physics.

Closed-loop endo-atmospheric ascent guidance for reusable launch vehicle

NASA Astrophysics Data System (ADS)

Sun, Hongsheng

This dissertation focuses on the development of a closed-loop endo-atmospheric ascent guidance algorithm for the 2nd generation reusable launch vehicle. Special attention has been given to the issues that impact on viability, complexity and reliability in on-board implementation. The algorithm is called once every guidance update cycle to recalculate the optimal solution based on the current flight condition, taking into account atmospheric effects and path constraints. This is different from traditional ascent guidance algorithms which operate in a simple open-loop mode inside atmosphere, and later switch to a closed-loop vacuum ascent guidance scheme. The classical finite difference method is shown to be well suited for fast solution of the constrained optimal three-dimensional ascent problem. The initial guesses for the solutions are generated using an analytical vacuum optimal ascent guidance algorithm. Homotopy method is employed to gradually introduce the aerodynamic forces to generate the optimal solution from the optimal vacuum solution. The vehicle chosen for this study is the Lockheed Martin X-33 lifting-body reusable launch vehicle. To verify the algorithm presented in this dissertation, a series of open-loop and closed-loop tests are performed for three different missions. Wind effects are also studied in the closed-loop simulations. For comparison, the solutions for the same missions are also obtained by two independent optimization softwares. The results clearly establish the feasibility of closed-loop endo-atmospheric ascent guidance of rocket-powered launch vehicles. ATO cases are also tested to assess the adaptability of the algorithm to autonomously incorporate the abort modes.

Marginal and apical bone stability after staged sinus floor augmentation using bone condensing implants with variable-thread design: a two-dimensional analysis.

PubMed

Younes, F; Eghbali, A; De Troyer, S; De Bruyckere, T; Cleymaet, R; Cosyn, J

2016-09-01

Studies on the vertical stability of augmented bone after sinus lifting differ substantially. In addition, long healing periods are usually advocated prior to implant installation. The purpose of this case series study was to evaluate the changes in bone height after sinus lifting with a bovine-derived xenograft and to evaluate the clinical outcome of bone condensing implants installed after a short healing period. Patients treated during the years 2010-2013 were re-examined using peri-apical radiographs to evaluate the changes in augmented bone height (BH) and marginal bone loss (BL). Fifty-seven of 70 eligible subjects (28 male and 29 female, mean age 56 years) attended for reassessment. Data were available for 53 sinus lifts and 105 implants installed after a mean healing period of 4.6±1.5 months. Implant survival was 99% after a mean time in function of 19±9 months. Baseline BH, BH at implant placement, and final BH were on average 3.87±1.74mm, 13.75±2.12mm, and 13.11±2.12mm, respectively (P<0.001). Mean BL was 0.51±0.65mm. Only limited resorption is to be expected after sinus lifting in the short term. A bone condensing implant can be used in the early healing phase with successful outcomes in terms of implant survival and bone adaptation. Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

KSC00pp1162

NASA Image and Video Library

2000-08-16

KENNEDY SPACE CENTER, FLA. -- Technicians facilitate the transfer the STS-106 payload to Atlantis on Launch Pad 39-B using the Payload Ground Handling Mechanism (PGHM). The circular structure shown is the docking adapter. The PGHM (pronounced pigem) is located inside the Payload Changeout Room (PCR) of each shuttle launch pad’s Rotating Service Structure. The PGHM removes payloads from a transportation canister and installs them into the orbiter. It is essentially NASA’s largest fork-lift

KSC-00pp1162

NASA Image and Video Library

2000-08-16

KENNEDY SPACE CENTER, FLA. -- Technicians facilitate the transfer the STS-106 payload to Atlantis on Launch Pad 39-B using the Payload Ground Handling Mechanism (PGHM). The circular structure shown is the docking adapter. The PGHM (pronounced pigem) is located inside the Payload Changeout Room (PCR) of each shuttle launch pad’s Rotating Service Structure. The PGHM removes payloads from a transportation canister and installs them into the orbiter. It is essentially NASA’s largest fork-lift

Adaptive grid embedding for the two-dimensional flux-split Euler equations. M.S. Thesis

NASA Technical Reports Server (NTRS)

Warren, Gary Patrick

1990-01-01

A numerical algorithm is presented for solving the 2-D flux-split Euler equations using a multigrid method with adaptive grid embedding. The method uses an unstructured data set along with a system of pointers for communication on the irregularly shaped grid topologies. An explicit two-stage time advancement scheme is implemented. A multigrid algorithm is used to provide grid level communication and to accelerate the convergence of the solution to steady state. Results are presented for a subcritical airfoil and a transonic airfoil with 3 levels of adaptation. Comparisons are made with a structured upwind Euler code which uses the same flux integration techniques of the present algorithm. Good agreement is obtained with converged surface pressure coefficients. The lift coefficients of the adaptive code are within 2 1/2 percent of the structured code for the sub-critical case and within 4 1/2 percent of the structured code for the transonic case using approximately one-third the number of grid points.

Evaluation of robotic-assisted platysmaplasty procedures in a cadaveric model using the da Vinci Surgical System.

PubMed

Taghizadeh, Farhan; Reiley, Carol; Mohr, Catherine; Paul, Malcolm

2014-03-01

We are evaluating the technical feasibility of robotic-assisted laparoscopic vertical-intermediate platysmaplasty in conjunction with an open rhytidectomy. In a cadaveric study, the da Vinci Surgical System was used to access certain angles in the lower neck that are difficult for traditional short incision, short flap procedures. Ergonomics, approach, and technical challenges were noted. To date, there are no published reports of robotic-assisted neck lifts, motivating us to assess its potential in this field of plastic surgery. Standard open technique short flap rhytidectomies with concurrent experimental robotic-assisted platysmaplasties (neck lifts) were performed on six cadavers with the da Vinci Si Surgical System(®) (Intuitive Surgical, Sunnyvale, CA, USA). The surgical procedures were performed on a diverse cadaver population from June 2011 to January 2012. The procedures included (1) submental incision and laser-assisted liposuction, (2) open rhytidectomy, and (3) robotic-assisted platysmaplasty using knot-free sutures. A variety of sutures and fat extraction techniques, coupled with 0° and 30° three-dimensional endoscopes, were utilized to optimize visualization of the platysma. An unaltered da Vinci Si Surgical System with currently available instruments was easily adaptable to neck lift surgery. Mid-neck platysma exposure was excellent, tissue handling was delicate and precise, and suturing was easily performed. Robotic-assisted surgery has the potential to improve outcomes in neck lifts by offering the ability to manipulate instruments with increased freedom of movement, scaled motion, tremor reduction, and stereoscopic three-dimensional visualization in the deep neck. Future clinical studies on live human patients can better assess subject and surgeon benefits arising from the use of the da Vinci system for neck lifts. Evidence obtained from multiple time series with or without the intervention, such as case studies. Dramatic results in uncontrolled trials might also be regarded as this type of evidence.

Reinforcement Learning for Constrained Energy Trading Games With Incomplete Information.

PubMed

Wang, Huiwei; Huang, Tingwen; Liao, Xiaofeng; Abu-Rub, Haitham; Chen, Guo

2017-10-01

This paper considers the problem of designing adaptive learning algorithms to seek the Nash equilibrium (NE) of the constrained energy trading game among individually strategic players with incomplete information. In this game, each player uses the learning automaton scheme to generate the action probability distribution based on his/her private information for maximizing his own averaged utility. It is shown that if one of admissible mixed-strategies converges to the NE with probability one, then the averaged utility and trading quantity almost surely converge to their expected ones, respectively. For the given discontinuous pricing function, the utility function has already been proved to be upper semicontinuous and payoff secure which guarantee the existence of the mixed-strategy NE. By the strict diagonal concavity of the regularized Lagrange function, the uniqueness of NE is also guaranteed. Finally, an adaptive learning algorithm is provided to generate the strategy probability distribution for seeking the mixed-strategy NE.

Lifting wavelet method of target detection

NASA Astrophysics Data System (ADS)

Han, Jun; Zhang, Chi; Jiang, Xu; Wang, Fang; Zhang, Jin

2009-11-01

Image target recognition plays a very important role in the areas of scientific exploration, aeronautics and space-to-ground observation, photography and topographic mapping. Complex environment of the image noise, fuzzy, all kinds of interference has always been to affect the stability of recognition algorithm. In this paper, the existence of target detection in real-time, accuracy problems, as well as anti-interference ability, using lifting wavelet image target detection methods. First of all, the use of histogram equalization, the goal difference method to obtain the region, on the basis of adaptive threshold and mathematical morphology operations to deal with the elimination of the background error. Secondly, the use of multi-channel wavelet filter wavelet transform of the original image de-noising and enhancement, to overcome the general algorithm of the noise caused by the sensitive issue of reducing the rate of miscarriage of justice will be the multi-resolution characteristics of wavelet and promotion of the framework can be designed directly in the benefits of space-time region used in target detection, feature extraction of targets. The experimental results show that the design of lifting wavelet has solved the movement of the target due to the complexity of the context of the difficulties caused by testing, which can effectively suppress noise, and improve the efficiency and speed of detection.

Site-Specific Preparation of Intact Solid–Liquid Interfaces by Label-Free In Situ Localization and Cryo-Focused Ion Beam Lift-Out

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

Zachman, Michael J.; Asenath-Smith, Emily; Estroff, Lara A.

Abstract Scanning transmission electron microscopy (STEM) allows atomic scale characterization of solid–solid interfaces, but has seen limited applications to solid–liquid interfaces due to the volatility of liquids in the microscope vacuum. Although cryo-electron microscopy is routinely used to characterize hydrated samples stabilized by rapid freezing, sample thinning is required to access the internal interfaces of thicker specimens. Here, we adapt cryo-focused ion beam (FIB) “lift-out,” a technique recently developed for biological specimens, to prepare intact internal solid–liquid interfaces for high-resolution structural and chemical analysis by cryo-STEM. To guide the milling process we introduce a label-freein situmethod of localizing subsurface structuresmore » in suitable materials by energy dispersive X-ray spectroscopy (EDX). Monte Carlo simulations are performed to evaluate the depth-probing capability of the technique, and show good qualitative agreement with experiment. We also detail procedures to produce homogeneously thin lamellae, which enable nanoscale structural, elemental, and chemical analysis of intact solid–liquid interfaces by analytical cryo-STEM. This work demonstrates the potential of cryo-FIB lift-out and cryo-STEM for understanding physical and chemical processes at solid–liquid interfaces.« less

Quality assurance in the production of pipe fittings by automatic laser-based material identification

NASA Astrophysics Data System (ADS)

Moench, Ingo; Peter, Laszlo; Priem, Roland; Sturm, Volker; Noll, Reinhard

1999-09-01

In plants of the chemical, nuclear and off-shore industry, application specific high-alloyed steels are used for pipe fittings. Mixing of different steel grades can lead to corrosion with severe consequential damages. Growing quality requirements and environmental responsibilities demand a 100% material control in the production of the pipe fittings. Therefore, LIFT, an automatic inspection machine, was developed to insure against any mix of material grades. LIFT is able to identify more than 30 different steel grades. The inspection method is based on Laser-Induced Breakdown Spectrometry (LIBS). An expert system, which can be easily trained and recalibrated, was developed for the data evaluation. The result of the material inspection is transferred to an external handling system via a PLC interface. The duration of the inspection process is 2 seconds. The graphical user interface was developed with respect to the requirements of an unskilled operator. The software is based on a realtime operating system and provides a safe and reliable operation. An interface for the remote maintenance by modem enables a fast operational support. Logged data are retrieved and evaluated. This is the basis for an adaptive improvement of the configuration of LIFT with respect to changing requirements in the production line. Within the first six months of routine operation, about 50000 pipe fittings were inspected.

An adaptive finite element method for the inequality-constrained Reynolds equation

NASA Astrophysics Data System (ADS)

Gustafsson, Tom; Rajagopal, Kumbakonam R.; Stenberg, Rolf; Videman, Juha

2018-07-01

We present a stabilized finite element method for the numerical solution of cavitation in lubrication, modeled as an inequality-constrained Reynolds equation. The cavitation model is written as a variable coefficient saddle-point problem and approximated by a residual-based stabilized method. Based on our recent results on the classical obstacle problem, we present optimal a priori estimates and derive novel a posteriori error estimators. The method is implemented as a Nitsche-type finite element technique and shown in numerical computations to be superior to the usually applied penalty methods.

Sequential Adaptive Multi-Modality Target Detection and Classification Using Physics Based Models

DTIC Science & Technology

2006-09-01

estimation," R. Raghuram, R. Raich and A.O. Hero, IEEE Intl. Conf. on Acoustics, Speech , and Signal Processing, Toulouse France, June 2006, <http...can then be solved using off-the-shelf classifiers such as radial basis functions, SVM, or kNN classifier structures. When applied to mine detection we...stage waveform selection for adaptive resource constrained state estimation," 2006 IEEE Intl. Conf. on Acoustics, Speech , and Signal Processing

Static aeroelastic behavior of an adaptive laminated piezoelectric composite wing

NASA Technical Reports Server (NTRS)

Weisshaar, T. A.; Ehlers, S. M.

1990-01-01

The effect of using an adaptive material to modify the static aeroelastic behavior of a uniform wing is examined. The wing structure is idealized as a laminated sandwich structure with piezoelectric layers in the upper and lower skins. A feedback system that senses the wing root loads applies a constant electric field to the piezoelectric actuator. Modification of pure torsional deformaton behavior and pure bending deformation are investigated, as is the case of an anisotropic composite swept wing. The use of piezoelectric actuators to create an adaptive structure is found to alter static aeroelastic behavior in that the proper choice of the feedback gain can increase or decrease the aeroelastic divergence speed. This concept also may be used to actively change the lift effectiveness of a wing. The ability to modify static aeroelastic behavior is limited by physical limitations of the piezoelectric material and the manner in which it is integrated into the parent structure.

Evolution in response to climate change: in pursuit of the missing evidence.

PubMed

Merilä, Juha

2012-09-01

Climate change is imposing intensified and novel selection pressures on organisms by altering abiotic and biotic environmental conditions on Earth, but studies demonstrating genetic adaptation to climate change mediated selection are still scarce. Evidence is accumulating to indicate that both genetic and ecological constrains may often limit populations' abilities to adapt to large scale effects of climate warming. These constraints may predispose many organisms to respond to climate change with range shifts and phenotypic plasticity, rather than through evolutionary adaptation. In general, broad conclusions about the role of evolutionary adaptation in mitigating climate change induced fitness loss in the wild are as yet difficult to make. Copyright © 2012 WILEY Periodicals, Inc.

KSC-2009-2464

NASA Image and Video Library

2009-04-01

CAPE CANAVERAL, Fla. – In High Bay 4 of the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida, a large crane lifts the Ares I-X upper stage simulator service module/service adapter segment to move it to a stand. Ares I-X is the test vehicle for the Ares I, which is part of the Constellation Program to return men to the moon and beyond. The Ares I-X is targeted for launch in July 2009. Photo credit: NASA/Kim Shiflett

Design and Construction of Aquaculture Facilities in Dredged Material Containment Areas

DTIC Science & Technology

1993-07-01

detail. The following discussion of centrifugal and axial flow pumps is adapted from Wheaton (1977), Baker (1987), and Baker and Bankston (1988...at a right angle to the impeller shaft. Axial flow propeller pumps are also used, especially in high-volume low-lift situations. The propeller may look...horizontal centrifugal pump or the axial flow pump may be used. Both of these pumps provide large volumes of water under low head conditions. Many

Dynamic analysis of an SDOF helicopter model featuring skid landing gear and an MR damper by considering the rotor lift factor and a Bingham number

NASA Astrophysics Data System (ADS)

Saleh, Muftah; Sedaghati, Ramin; Bhat, Rama

2018-06-01

The present study addresses the performance of a skid landing gear (SLG) system of a rotorcraft impacting the ground at a vertical sink rate of up to 4.5 ms‑1. The impact attitude is assumed to be level as per chapter 527 of the Airworthiness Manual of Transport Canada Civil Aviation and part 27 of the Federal Aviation Regulations of the US Federal Aviation Administration. A single degree of freedom helicopter model is investigated under different values of rotor lift factor, L. In this study, three SLG versions are evaluated: (a) standalone conventional SLG; (b) SLG equipped with a passive viscous damper; and (c) SLG incorporated a magnetorheological energy absorber (MREA). The non-dimensional solutions of the helicopter models show that the two former SLG systems suffer adaptability issues with variations in the impact velocity and the rotor lift factor. Therefore, the alternative successful choice is to employ the MREA. Two different optimum Bingham numbers for compression and rebound strokes are defined. A new chart, called the optimum Bingham number versus rotor lift factor ‘B{i}o-L’, is introduced in this study to correlate the optimum Bingham numbers to the variation in the rotor lift factor and to provide more accessibility from the perspective of control design. The chart shows that the optimum Bingham number for the compression stroke is inversely linearly proportional to the increase in the rotor lift factor. This alleviates the impact force on the system and reduces the amount of magnetorheological yield force that would be generated. On the contrary, the optimum Bingham number for the rebound stroke is found to be directly linearly proportional to the rotor lift factor. This ensures controllable attenuation of the restoring force of the linear spring element. This idea can be exploited to generate charts for different landing attitudes and sink rates. In this article, the response of the helicopter equipped with the conventional undamped, damped, and MREA based SLG are numerically simulated using three sets of Bingham numbers. Namely, an underestimated, optimum, and overestimated Bingham number for every stroke. The simulation results depict that the only feasible solution is when the MREA generates the optimum damping force corresponding to the optimum Bingham numbers. Under this circumstance, the MREA utilizes the available energy absorption stroke to attain a soft landing. Furthermore, in the rebound stroke, the optimum damping force resettles the helicopter to its equilibrium position and prevents oscillations after the end of the rebound stroke.

Improving Service Management in the Internet of Things

PubMed Central

Sammarco, Chiara; Iera, Antonio

2012-01-01

In the Internet of Things (IoT) research arena, many efforts are devoted to adapt the existing IP standards to emerging IoT nodes. This is the direction followed by three Internet Engineering Task Force (IETF) Working Groups, which paved the way for research on IP-based constrained networks. Through a simplification of the whole TCP/IP stack, resource constrained nodes become direct interlocutors of application level entities in every point of the network. In this paper we analyze some side effects of this solution, when in the presence of large amounts of data to transmit. In particular, we conduct a performance analysis of the Constrained Application Protocol (CoAP), a widely accepted web transfer protocol for the Internet of Things, and propose a service management enhancement that improves the exploitation of the network and node resources. This is specifically thought for constrained nodes in the abovementioned conditions and proves to be able to significantly improve the node energetic performance when in the presence of large resource representations (hence, large data transmissions).

Low bit-rate image compression via adaptive down-sampling and constrained least squares upconversion.

PubMed

Wu, Xiaolin; Zhang, Xiangjun; Wang, Xiaohan

2009-03-01

Recently, many researchers started to challenge a long-standing practice of digital photography: oversampling followed by compression and pursuing more intelligent sparse sampling techniques. In this paper, we propose a practical approach of uniform down sampling in image space and yet making the sampling adaptive by spatially varying, directional low-pass prefiltering. The resulting down-sampled prefiltered image remains a conventional square sample grid, and, thus, it can be compressed and transmitted without any change to current image coding standards and systems. The decoder first decompresses the low-resolution image and then upconverts it to the original resolution in a constrained least squares restoration process, using a 2-D piecewise autoregressive model and the knowledge of directional low-pass prefiltering. The proposed compression approach of collaborative adaptive down-sampling and upconversion (CADU) outperforms JPEG 2000 in PSNR measure at low to medium bit rates and achieves superior visual quality, as well. The superior low bit-rate performance of the CADU approach seems to suggest that oversampling not only wastes hardware resources and energy, and it could be counterproductive to image quality given a tight bit budget.

Adaptive optimal control of unknown constrained-input systems using policy iteration and neural networks.

PubMed

Modares, Hamidreza; Lewis, Frank L; Naghibi-Sistani, Mohammad-Bagher

2013-10-01

This paper presents an online policy iteration (PI) algorithm to learn the continuous-time optimal control solution for unknown constrained-input systems. The proposed PI algorithm is implemented on an actor-critic structure where two neural networks (NNs) are tuned online and simultaneously to generate the optimal bounded control policy. The requirement of complete knowledge of the system dynamics is obviated by employing a novel NN identifier in conjunction with the actor and critic NNs. It is shown how the identifier weights estimation error affects the convergence of the critic NN. A novel learning rule is developed to guarantee that the identifier weights converge to small neighborhoods of their ideal values exponentially fast. To provide an easy-to-check persistence of excitation condition, the experience replay technique is used. That is, recorded past experiences are used simultaneously with current data for the adaptation of the identifier weights. Stability of the whole system consisting of the actor, critic, system state, and system identifier is guaranteed while all three networks undergo adaptation. Convergence to a near-optimal control law is also shown. The effectiveness of the proposed method is illustrated with a simulation example.

Adaptive nearly optimal control for a class of continuous-time nonaffine nonlinear systems with inequality constraints.

PubMed

Fan, Quan-Yong; Yang, Guang-Hong

2017-01-01

The state inequality constraints have been hardly considered in the literature on solving the nonlinear optimal control problem based the adaptive dynamic programming (ADP) method. In this paper, an actor-critic (AC) algorithm is developed to solve the optimal control problem with a discounted cost function for a class of state-constrained nonaffine nonlinear systems. To overcome the difficulties resulting from the inequality constraints and the nonaffine nonlinearities of the controlled systems, a novel transformation technique with redesigned slack functions and a pre-compensator method are introduced to convert the constrained optimal control problem into an unconstrained one for affine nonlinear systems. Then, based on the policy iteration (PI) algorithm, an online AC scheme is proposed to learn the nearly optimal control policy for the obtained affine nonlinear dynamics. Using the information of the nonlinear model, novel adaptive update laws are designed to guarantee the convergence of the neural network (NN) weights and the stability of the affine nonlinear dynamics without the requirement for the probing signal. Finally, the effectiveness of the proposed method is validated by simulation studies. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

ICPS Removal from Shipping Container

NASA Image and Video Library

2017-03-09

Inside the United Launch Alliance (ULA) Horizontal Integration Facility at Cape Canaveral Air Force Station in Florida, a crane lifts the shipping container cover away from the Interim Cryogenic Propulsion Stage (ICPS) for NASA's Space Launch System rocket, followed by the ICPS bring removed and placed on a work stand for processing. The ICPS is the first integrated piece of flight hardware to arrive for the SLS. The ICPS arrived from the ULA facility in Decatur, Alabama. The ICPS is the in-space stage that is located toward the top of the rocket, between the Launch Vehicle Stage Adapter and the Orion Spacecraft Adapter. It will provide some of the in-space propulsion during Orion's first flight test atop the SLS on Exploration Mission 1.

Constrained Total Energy Expenditure and Metabolic Adaptation to Physical Activity in Adult Humans.

PubMed

Pontzer, Herman; Durazo-Arvizu, Ramon; Dugas, Lara R; Plange-Rhule, Jacob; Bovet, Pascal; Forrester, Terrence E; Lambert, Estelle V; Cooper, Richard S; Schoeller, Dale A; Luke, Amy

2016-02-08

Current obesity prevention strategies recommend increasing daily physical activity, assuming that increased activity will lead to corresponding increases in total energy expenditure and prevent or reverse energy imbalance and weight gain [1-3]. Such Additive total energy expenditure models are supported by exercise intervention and accelerometry studies reporting positive correlations between physical activity and total energy expenditure [4] but are challenged by ecological studies in humans and other species showing that more active populations do not have higher total energy expenditure [5-8]. Here we tested a Constrained total energy expenditure model, in which total energy expenditure increases with physical activity at low activity levels but plateaus at higher activity levels as the body adapts to maintain total energy expenditure within a narrow range. We compared total energy expenditure, measured using doubly labeled water, against physical activity, measured using accelerometry, for a large (n = 332) sample of adults living in five populations [9]. After adjusting for body size and composition, total energy expenditure was positively correlated with physical activity, but the relationship was markedly stronger over the lower range of physical activity. For subjects in the upper range of physical activity, total energy expenditure plateaued, supporting a Constrained total energy expenditure model. Body fat percentage and activity intensity appear to modulate the metabolic response to physical activity. Models of energy balance employed in public health [1-3] should be revised to better reflect the constrained nature of total energy expenditure and the complex effects of physical activity on metabolic physiology. Copyright © 2016 Elsevier Ltd. All rights reserved.

Large-Scale Parallel Simulations of Turbulent Combustion using Combined Dimension Reduction and Tabulation of Chemistry

DTIC Science & Technology

2012-05-22

tabulation of the reduced space is performed using the In Situ Adaptive Tabulation ( ISAT ) algorithm. In addition, we use x2f mpi – a Fortran library...for parallel vector-valued function evaluation (used with ISAT in this context) – to efficiently redistribute the chemistry workload among the...Constrained-Equilibrium (RCCE) method, and tabulation of the reduced space is performed using the In Situ Adaptive Tabulation ( ISAT ) algorithm. In addition

A Generalized Framework for Constrained Design Optimization of General Supersonic Configurations Using Adjoint Based Sensitivity Derivatives

NASA Technical Reports Server (NTRS)

Karman, Steve L., Jr.

2011-01-01

The Aeronautics Research Mission Directorate (ARMD) sent out an NASA Research Announcement (NRA) for proposals soliciting research and technical development. The proposed research program was aimed at addressing the desired milestones and outcomes of ROA (ROA-2006) Subtopic A.4.1.1 Advanced Computational Methods. The second milestone, SUP.1.06.02 Robust, validated mesh adaptation and error quantification for near field Computational Fluid Dynamics (CFD), was addressed by the proposed research. Additional research utilizing the direct links to geometry through a CAD interface enabled by this work will allow for geometric constraints to be applied and address the final milestone, SUP2.07.06 Constrained low-drag supersonic aerodynamic design capability. The original product of the proposed research program was an integrated system of tools that can be used for the mesh mechanics required for rapid high fidelity analysis and for design of supersonic cruise vehicles. These Euler and Navier-Stokes volume grid manipulation tools were proposed to efficiently use parallel processing. The mesh adaptation provides a systematic approach for achieving demonstrated levels of accuracy in the solutions. NASA chose to fund only the mesh generation/adaptation portion of the proposal. So this report describes the completion of the proposed tasks for mesh creation, manipulation and adaptation as it pertains to sonic boom prediction of supersonic configurations.

Convergent local adaptation to climate in distantly related conifers.

PubMed

Yeaman, Sam; Hodgins, Kathryn A; Lotterhos, Katie E; Suren, Haktan; Nadeau, Simon; Degner, Jon C; Nurkowski, Kristin A; Smets, Pia; Wang, Tongli; Gray, Laura K; Liepe, Katharina J; Hamann, Andreas; Holliday, Jason A; Whitlock, Michael C; Rieseberg, Loren H; Aitken, Sally N

2016-09-23

When confronted with an adaptive challenge, such as extreme temperature, closely related species frequently evolve similar phenotypes using the same genes. Although such repeated evolution is thought to be less likely in highly polygenic traits and distantly related species, this has not been tested at the genome scale. We performed a population genomic study of convergent local adaptation among two distantly related species, lodgepole pine and interior spruce. We identified a suite of 47 genes, enriched for duplicated genes, with variants associated with spatial variation in temperature or cold hardiness in both species, providing evidence of convergent local adaptation despite 140 million years of separate evolution. These results show that adaptation to climate can be genetically constrained, with certain key genes playing nonredundant roles. Copyright © 2016, American Association for the Advancement of Science.

The Trainability of Adolescent Soccer Players to Brief Periodized Complex Training.

PubMed

Chatzinikolaou, Athanasios; Michaloglou, Konstantinos; Avloniti, Alexandra; Leontsini, Diamanda; Deli, Chariklia K; Vlachopoulos, Dimitris; Gracia-Marco, Luis; Arsenis, Sotirios; Athanailidis, Ioannis; Draganidis, Dimitrios; Jamurtas, Athanasios Z; Williams, Craig A; Fatouros, Ioannis G

2018-05-01

To investigate the effect of a complex, short-term strength/power training protocol on performance and body composition of elite early adolescent soccer players. Twenty-two players (14-15 y) were randomly assigned to (1) an experimental group (N = 12; participated in a 5-wk training protocol with traditional multijoint power resistance exercises, Olympic-style lifts, plyometric drills, and speed work; 4 times per week) or (2) a control group (N = 10). Strength and power performance (jumping, speed, change of direction, repeated sprint ability, endurance, isokinetic strength of knee flexors and extensors, maximal strength in various lifts, and speed-endurance) were evaluated pretraining and posttraining. Cessation of training for 5 weeks in the control group induced a marked performance deterioration (∼5%-20%). Training not only prevented strength performance deterioration but also increased it (∼2%-30%). Endurance and repeated sprint ability declined to a smaller extent in experimental group compared with control group (15% vs 7.5%). Isometric strength and body composition remained unaltered in both groups. Results demonstrate that (1) young players exhibit a high level of trainability of their strength/power performance (but not endurance) in response to a short-term complex training protocol during early adolescence, (2) Olympic-style lifts are characterized by increased safety in this age group and appear to be highly effective, (3) lifts incorporating a hip thrust result in increased strength of both knee extensors and flexors, (4) cessation of training for only 5 weeks results in marked deterioration of strength/power and endurance performance, and (5) improvement of strength/power performance may be related to neural-based adaptation as body composition remained unaffected.

Optimization of flexible wing structures subject to strength and induced drag constraints

NASA Technical Reports Server (NTRS)

Haftka, R. T.

1977-01-01

An optimization procedure for designing wing structures subject to stress, strain, and drag constraints is presented. The optimization method utilizes an extended penalty function formulation for converting the constrained problem into a series of unconstrained ones. Newton's method is used to solve the unconstrained problems. An iterative analysis procedure is used to obtain the displacements of the wing structure including the effects of load redistribution due to the flexibility of the structure. The induced drag is calculated from the lift distribution. Approximate expressions for the constraints used during major portions of the optimization process enhance the efficiency of the procedure. A typical fighter wing is used to demonstrate the procedure. Aluminum and composite material designs are obtained. The tradeoff between weight savings and drag reduction is investigated.

Analytical modeling and experimental evaluation of a passively morphing ornithopter wing

NASA Astrophysics Data System (ADS)

Wissa, Aimy A.

Ornithopters or flapping wing Unmanned Aerial Vehicles (UAVs) have potential applications in both civil and military sectors. Amongst all categories of UAVs, ornithopters have a unique ability to fly in low Reynolds number flight regimes and have the agility and maneuverability of rotary wing aircraft. In nature, birds achieve such performance by exploiting various wing kinematics known as gaits. The objective of this work was to improve the steady level flight wing performance of an ornithopter by implementing the Continuous Vortex Gait (CVG) using a novel passive compliant spine. The CVG is a set of bio-inspired kinematics that natural flyers use to produce lift and thrust during steady level flight. A significant contribution of this work was the recognition that the CVG is an avian gait that could be achieved using a passive morphing mechanism. In contrast to rigid-link mechanisms and active approaches, reported by other researchers in the open literature, passive morphing mechanisms require no additional energy expenditure, while introducing minimal weight addition and complexity. During the execution of the CVG, the avian wing wrist is the primary joint responsible for the wing shape changes. Thus a compliant mechanism, called a compliant spine, was fabricated, and integrated in the ornithopter's wing leading edge spar where an avian wrist would normally exist, namely at 37% of the wing half span. Each compliant spine was designed to be flexible in bending during the wing upstroke and stiff in bending during the wing downstroke. Inserting a variable stiffness compliant mechanism in the leading edge (LE) spar of the ornithopter could affect its structural stability. An analytical model was developed to determine the structural stability of the ornithopter LE spar. The model was validated using experimental measurements. The LE spar equations of motion were then reformulated into Mathieu's equation and the LE spar was proven to be structurally stable with a compliant spine design insert. A research ornithopter platform was tested in air and in vacuum as well as in free and constrained flight with various compliant spine designs inserted in its wings. Results from the constrained flight tests indicated that the ornithopter with a compliant spine inserted in its wings consumed 45% less electrical power and produced 16% of its weight in additional lift, without incurring any thrust penalties. Results from, the vacuum constrained tests attributed these benefits to aerodynamic effects rather than inertial effects. Free flight tests were performed at Wright Patterson Air Force Base, which houses the largest indoor flight laboratory in the country. The wing kinematics along with the vehicle dynamics were captured during this testing using ViconRTM motion tracking cameras. These flight tests proved to be successful in producing consistent and repeatable flight data over more than eight free flight flapping cycles of free flight and validated a new and novel testing technique. The ornithopter body dynamics were shown to be significant, i.e. +/-4gs. Inserting the compliant spine into the leading edge spar of the ornithopter during free flight reduced the baseline configuration body vertical center of mass positive acceleration by 69%, which translates into overall lift gains. It also increased the horizontal propulsive force by 300%, which translates into thrust gains.

Perceiving Affordances for Fitting through Apertures

ERIC Educational Resources Information Center

Ishak, Shaziela; Adolph, Karen E.; Lin, Grace C.

2008-01-01

Affordances--possibilities for action--are constrained by the match between actors and their environments. For motor decisions to be adaptive, affordances must be detected accurately. Three experiments examined the correspondence between motor decisions and affordances as participants reached through apertures of varying size. A psychophysical…

KSC-2009-2463

NASA Image and Video Library

2009-04-01

CAPE CANAVERAL, Fla. –In High Bay 4 of the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida, a large crane is attached to the Ares I-X upper stage simulator service module/service adapter segment to lift and move it to a stand. Ares I-X is the test vehicle for the Ares I, which is part of the Constellation Program to return men to the moon and beyond. The Ares I-X is targeted for launch in July 2009. Photo credit: NASA/Kim Shiflett

Drag reduction in nature

NASA Technical Reports Server (NTRS)

Bushnell, D. M.; Moore, K. J.

1991-01-01

Recent studies on the drag-reducing shapes, structures, and behaviors of swimming and flying animals are reviewed, with an emphasis on potential analogs in vehicle design. Consideration is given to form drag reduction (turbulent flow, vortex generation, mass transfer, and adaptations for body-intersection regions), skin-friction drag reduction (polymers, surfactants, and bubbles as surface 'additives'), reduction of the drag due to lift, drag-reduction studies on porpoises, and drag-reducing animal behavior (e.g., leaping out of the water by porpoises). The need for further research is stressed.

Real-Time Adaptive Control of Mixing in a Plane Shear Layer

DTIC Science & Technology

1994-02-02

l’icoulement d’un fuide visqueux incompressible autour d’un cylinder fixe ou en rotation. Effet Magnus . J. Mdc. 14, 109-134. TANEDA, S. 1977 Visual study...Mokhtarian & Yokomizo 1990), and in lift enhancement schemes employing the Magnus effect (Swanson 1961). Rotation of all or part of a body may also have...coordinate system. In this work, the body-fitted grid is simply one of cylindrical polar coordinates and is time-independent, except for a = 3.25 where

New airfoil sections for straight bladed turbine

NASA Astrophysics Data System (ADS)

Boumaza, B.

1987-07-01

A theoretical investigation of aerodynamic performance for vertical axis Darrieus wind turbine with new airfoils sections is carried out. The blade section aerodynamics characteristics are determined from turbomachines cascade model. The model is also adapted to the vertical Darrieus turbine for the performance prediction of the machine. In order to choose appropriate value of zero-lift-drag coefficient in calculation, an analytical expression is introduced as function of chord-radius ratio and Reynolds numbers. New airfoils sections are proposed and analyzed for straight-bladed turbine.

Modern high-strength steels for heavily loaded gearing (a review of engineering patents)

NASA Astrophysics Data System (ADS)

Voronenko, B. I.

1996-08-01

In order to increase the service life of machines the life of their parts should be increased. For example, in machine tool and lifting-and-transport manufacture the maintenance cost of the equipment over the duration of its operation often exceeds the cost of the new equipment by a factor of 10-20. This imposes strict requirements on structural materials for heavily loaded gearings, including the development of high-strength, wear-resistant, manufacture-adaptable, and economically alloyed steels.

Evolution Is an Experiment: Assessing Parallelism in Crop Domestication and Experimental Evolution: (Nei Lecture, SMBE 2014, Puerto Rico).

PubMed

Gaut, Brandon S

2015-07-01

In this commentary, I make inferences about the level of repeatability and constraint in the evolutionary process, based on two sets of replicated experiments. The first experiment is crop domestication, which has been replicated across many different species. I focus on results of whole-genome scans for genes selected during domestication and ask whether genes are, in fact, selected in parallel across different domestication events. If genes are selected in parallel, it implies that the number of genetic solutions to the challenge of domestication is constrained. However, I find no evidence for parallel selection events either between species (maize vs. rice) or within species (two domestication events within beans). These results suggest that there are few constraints on genetic adaptation, but conclusions must be tempered by several complicating factors, particularly the lack of explicit design standards for selection screens. The second experiment involves the evolution of Escherichia coli to thermal stress. Unlike domestication, this highly replicated experiment detected a limited set of genes that appear prone to modification during adaptation to thermal stress. However, the number of potentially beneficial mutations within these genes is large, such that adaptation is constrained at the genic level but much less so at the nucleotide level. Based on these two experiments, I make the general conclusion that evolution is remarkably flexible, despite the presence of epistatic interactions that constrain evolutionary trajectories. I also posit that evolution is so rapid that we should establish a Speciation Prize, to be awarded to the first researcher who demonstrates speciation with a sexual organism in the laboratory. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Aerodynamic influence coefficient method using singularity splines

NASA Technical Reports Server (NTRS)

Mercer, J. E.; Weber, J. A.; Lesferd, E. P.

1974-01-01

A numerical lifting surface formulation, including computed results for planar wing cases is presented. This formulation, referred to as the vortex spline scheme, combines the adaptability to complex shapes offered by paneling schemes with the smoothness and accuracy of loading function methods. The formulation employes a continuous distribution of singularity strength over a set of panels on a paneled wing. The basic distributions are independent, and each satisfied all the continuity conditions required of the final solution. These distributions are overlapped both spanwise and chordwise. Boundary conditions are satisfied in a least square error sense over the surface using a finite summing technique to approximate the integral. The current formulation uses the elementary horseshoe vortex as the basic singularity and is therefore restricted to linearized potential flow. As part of the study, a non planar development was considered, but the numerical evaluation of the lifting surface concept was restricted to planar configurations. Also, a second order sideslip analysis based on an asymptotic expansion was investigated using the singularity spline formulation.

An engineering study of hybrid adaptation of wind tunnel walls for three-dimensional testing

NASA Technical Reports Server (NTRS)

Brown, Clinton; Kalumuck, Kenneth; Waxman, David

1987-01-01

Solid wall tunnels having only upper and lower walls flexing are described. An algorithm for selecting the wall contours for both 2 and 3 dimensional wall flexure is presented and numerical experiments are used to validate its applicability to the general test case of 3 dimensional lifting aircraft models in rectangular cross section wind tunnels. The method requires an initial approximate representation of the model flow field at a given lift with wallls absent. The numerical methods utilized are derived by use of Green's source solutions obtained using the method of images; first order linearized flow theory is employed with Prandtl-Glauert compressibility transformations. Equations are derived for the flexed shape of a simple constant thickness plate wall under the influence of a finite number of jacks in an axial row along the plate centerline. The Green's source methods are developed to provide estimations of residual flow distortion (interferences) with measured wall pressures and wall flow inclinations as inputs.

Timing of intermittent torque control with wire-driven gait training robot lifting toe trajectory for trip avoidance.

PubMed

Miyake, Tamon; Kobayashi, Yo; Fujie, Masakatsu G; Sugano, Shigeki

2017-07-01

Gait training robots are useful for changing gait patterns and decreasing risk of trip. Previous research has reported that decreasing duration of the assistance or guidance of the robot is beneficial for efficient gait training. Although robotic intermittent control method for assisting joint motion has been established, the effect of the robot intervention timing on change of toe clearance is unclear. In this paper, we tested different timings of applying torque to the knee, employing the intermittent control of a gait training robot to increase toe clearance throughout the swing phase. We focused on knee flexion motion and designed a gait training robot that can apply flexion torque to the knee with a wire-driven system. We used a method of timing detecting for the robot conducting torque control based on information from the hip, knee, and ankle angles to establish a non-time dependent parameter that can be used to adapt to gait change, such as gait speed. We carried out an experiment in which the conditions were four time points: starting the swing phase, lifting the foot, maintaining knee flexion, and finishing knee flexion. The results show that applying flexion torque to the knee at the time point when people start lifting their toe is effective for increasing toe clearance in the whole swing phase.

Reynolds number scalability of bristled wings performing clap and fling

NASA Astrophysics Data System (ADS)

Jacob, Skyler; Kasoju, Vishwa; Santhanakrishnan, Arvind

2017-11-01

Tiny flying insects such as thrips show a distinctive physical adaptation in the use of bristled wings. Thrips use wing-wing interaction kinematics for flapping, in which a pair of wings clap together at the end of upstroke and fling apart at the beginning of downstroke. Previous studies have shown that the use of bristled wings can reduce the forces needed for clap and fling at Reynolds number (Re) on the order of 10. This study examines if the fluid dynamic advantages of using bristled wings also extend to higher Re on the order of 100. A robotic clap and fling platform was used for this study, in which a pair of physical wing models were programmed to execute clap and fling kinematics. Force measurements were conducted on solid (non-bristled) and bristled wing pairs. The results show lift and drag forces were both lower for bristled wings when compared to solid wings for Re ranging from 1-10, effectively increasing peak lift to peak drag ratio of bristled wings. However, peak lift to peak drag ratio was lower for bristled wings at Re =120 as compared to solid wings, suggesting that bristled wings may be uniquely advantageous for Re on the orders of 1-10. Flow structures visualized using particle image velocimetry (PIV) and their impact on force production will be presented.

Planform, aero-structural, and flight control optimization for tailless morphing aircraft

NASA Astrophysics Data System (ADS)

Molinari, Giulio; Arrieta, Andres F.; Ermanni, Paolo

2015-04-01

Tailless airplanes with swept wings rely on variations of the spanwise lift distribution to provide controllability in roll, pitch and yaw. Conventionally, this is achieved utilizing multiple control surfaces, such as elevons, on the wing trailing edge. As every flight condition requires different control moments (e.g. to provide pitching moment equilibrium), these surfaces are practically permanently displaced. Due to their nature, causing discontinuities, corners and gaps, they bear aerodynamic penalties, mostly in terms of shape drag. Shape adaptation, by means of chordwise morphing, has the potential of varying the lift of a wing section by deforming its profile in a way that minimizes the resulting drag. Furthermore, as the shape can be varied differently along the wingspan, the lift distribution can be tailored to each specific flight condition. For this reason, tailless aircraft appear as a prime choice to apply morphing techniques, as the attainable benefits are potentially significant. In this work, we present a methodology to determine the optimal planform, profile shape, and morphing structure for a tailless aircraft. The employed morphing concept is based on a distributed compliance structure, actuated by Macro Fiber Composite (MFC) piezoelectric elements. The multidisciplinary optimization is performed considering the static and dynamic aeroelastic behavior of the resulting structure. The goal is the maximization of the aerodynamic efficiency while guaranteeing the controllability of the plane, by means of morphing, in a set of flight conditions.

Convergence, Degeneracy, and Control

ERIC Educational Resources Information Center

Green, David W.; Crinion, Jenny; Price, Cathy J.

2006-01-01

Understanding the neural representation and control of language in normal bilingual speakers provides insights into the factors that constrain the acquisition of another language, insights into the nature of language expertise, and an understanding of the brain as an adaptive system. We illustrate both functional and structural brain changes…

Vortical Flow Prediction Using an Adaptive Unstructured Grid Method

NASA Technical Reports Server (NTRS)

Pirzadeh, Shahyar Z.

2001-01-01

A computational fluid dynamics (CFD) method has been employed to compute vortical flows around slender wing/body configurations. The emphasis of the paper is on the effectiveness of an adaptive grid procedure in "capturing" concentrated vortices generated at sharp edges or flow separation lines of lifting surfaces flying at high angles of attack. The method is based on a tetrahedral unstructured grid technology developed at the NASA Langley Research Center. Two steady-state, subsonic, inviscid and Navier-Stokes flow test cases are presented to demonstrate the applicability of the method for solving practical vortical flow problems. The first test case concerns vortex flow over a simple 65deg delta wing with different values of leading-edge bluntness, and the second case is that of a more complex fighter configuration. The superiority of the adapted solutions in capturing the vortex flow structure over the conventional unadapted results is demonstrated by comparisons with the windtunnel experimental data. The study shows that numerical prediction of vortical flows is highly sensitive to the local grid resolution and that the implementation of grid adaptation is essential when applying CFD methods to such complicated flow problems.

Stochastic Averaging for Constrained Optimization With Application to Online Resource Allocation

NASA Astrophysics Data System (ADS)

Chen, Tianyi; Mokhtari, Aryan; Wang, Xin; Ribeiro, Alejandro; Giannakis, Georgios B.

2017-06-01

Existing approaches to resource allocation for nowadays stochastic networks are challenged to meet fast convergence and tolerable delay requirements. The present paper leverages online learning advances to facilitate stochastic resource allocation tasks. By recognizing the central role of Lagrange multipliers, the underlying constrained optimization problem is formulated as a machine learning task involving both training and operational modes, with the goal of learning the sought multipliers in a fast and efficient manner. To this end, an order-optimal offline learning approach is developed first for batch training, and it is then generalized to the online setting with a procedure termed learn-and-adapt. The novel resource allocation protocol permeates benefits of stochastic approximation and statistical learning to obtain low-complexity online updates with learning errors close to the statistical accuracy limits, while still preserving adaptation performance, which in the stochastic network optimization context guarantees queue stability. Analysis and simulated tests demonstrate that the proposed data-driven approach improves the delay and convergence performance of existing resource allocation schemes.

Environment determines evolutionary trajectory in a constrained phenotypic space

PubMed Central

Fraebel, David T; Mickalide, Harry; Schnitkey, Diane; Merritt, Jason; Kuhlman, Thomas E; Kuehn, Seppe

2017-01-01

Constraints on phenotypic variation limit the capacity of organisms to adapt to the multiple selection pressures encountered in natural environments. To better understand evolutionary dynamics in this context, we select Escherichia coli for faster migration through a porous environment, a process which depends on both motility and growth. We find that a trade-off between swimming speed and growth rate constrains the evolution of faster migration. Evolving faster migration in rich medium results in slow growth and fast swimming, while evolution in minimal medium results in fast growth and slow swimming. In each condition parallel genomic evolution drives adaptation through different mutations. We show that the trade-off is mediated by antagonistic pleiotropy through mutations that affect negative regulation. A model of the evolutionary process shows that the genetic capacity of an organism to vary traits can qualitatively depend on its environment, which in turn alters its evolutionary trajectory. DOI: http://dx.doi.org/10.7554/eLife.24669.001 PMID:28346136

A Constrained Genetic Algorithm with Adaptively Defined Fitness Function in MRS Quantification

NASA Astrophysics Data System (ADS)

Papakostas, G. A.; Karras, D. A.; Mertzios, B. G.; Graveron-Demilly, D.; van Ormondt, D.

MRS Signal quantification is a rather involved procedure and has attracted the interest of the medical engineering community, regarding the development of computationally efficient methodologies. Significant contributions based on Computational Intelligence tools, such as Neural Networks (NNs), demonstrated a good performance but not without drawbacks already discussed by the authors. On the other hand preliminary application of Genetic Algorithms (GA) has already been reported in the literature by the authors regarding the peak detection problem encountered in MRS quantification using the Voigt line shape model. This paper investigates a novel constrained genetic algorithm involving a generic and adaptively defined fitness function which extends the simple genetic algorithm methodology in case of noisy signals. The applicability of this new algorithm is scrutinized through experimentation in artificial MRS signals interleaved with noise, regarding its signal fitting capabilities. Although extensive experiments with real world MRS signals are necessary, the herein shown performance illustrates the method's potential to be established as a generic MRS metabolites quantification procedure.

Climate change in fish: effects of respiratory constraints on optimal life history and behaviour.

PubMed

Holt, Rebecca E; Jørgensen, Christian

2015-02-01

The difference between maximum metabolic rate and standard metabolic rate is referred to as aerobic scope, and because it constrains performance it is suggested to constitute a key limiting process prescribing how fish may cope with or adapt to climate warming. We use an evolutionary bioenergetics model for Atlantic cod (Gadus morhua) to predict optimal life histories and behaviours at different temperatures. The model assumes common trade-offs and predicts that optimal temperatures for growth and fitness lie below that for aerobic scope; aerobic scope is thus a poor predictor of fitness at high temperatures. Initially, warming expands aerobic scope, allowing for faster growth and increased reproduction. Beyond the optimal temperature for fitness, increased metabolic requirements intensify foraging and reduce survival; oxygen budgeting conflicts thus constrain successful completion of the life cycle. The model illustrates how physiological adaptations are part of a suite of traits that have coevolved. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

The NIST SPIDER, A Robot Crane

PubMed Central

Albus, James; Bostelman, Roger; Dagalakis, Nicholas

1992-01-01

The Robot Systems Division of the National Institute of Standards and Technology has been experimenting for several years with new concepts for robot cranes. These concepts utilize the basic idea of the Stewart Platform parallel link manipulator. The unique feature of the NIST approach is to use cables as the parallel links and to use winches as the actuators. So long as the cables are all in tension, the load is kinematically constrained, and the cables resist perturbing forces and moments with equal stiffness to both positive and negative loads. The result is that the suspended load is constrained with a mechanical stiffness determined by the elasticity of the cables, the suspended weight, and the geometry of the mechanism. Based on these concepts, a revolutionary new type of robot crane, the NIST SPIDER (Stewart Platform Instrumented Drive Environmental Robot) has been developed that can control the position, velocity, and force of tools and heavy machinery in all six degrees of freedom (x, y, z, roll, pitch, and yaw). Depending on what is suspended from its work platform, the SPIDER can perform a variety of tasks. Examples are: cutting, excavating and grading, shaping and finishing, lifting and positioning. A 6 m version of the SPIDER has been built and critical performance characteristics analyzed. PMID:28053439

The NIST SPIDER, A Robot Crane.

PubMed

Albus, James; Bostelman, Roger; Dagalakis, Nicholas

1992-01-01

The Robot Systems Division of the National Institute of Standards and Technology has been experimenting for several years with new concepts for robot cranes. These concepts utilize the basic idea of the Stewart Platform parallel link manipulator. The unique feature of the NIST approach is to use cables as the parallel links and to use winches as the actuators. So long as the cables are all in tension, the load is kinematically constrained, and the cables resist perturbing forces and moments with equal stiffness to both positive and negative loads. The result is that the suspended load is constrained with a mechanical stiffness determined by the elasticity of the cables, the suspended weight, and the geometry of the mechanism. Based on these concepts, a revolutionary new type of robot crane, the NIST SPIDER (Stewart Platform Instrumented Drive Environmental Robot) has been developed that can control the position, velocity, and force of tools and heavy machinery in all six degrees of freedom ( x, y, z , roll, pitch, and yaw). Depending on what is suspended from its work platform, the SPIDER can perform a variety of tasks. Examples are: cutting, excavating and grading, shaping and finishing, lifting and positioning. A 6 m version of the SPIDER has been built and critical performance characteristics analyzed.

Lift producing device exhibiting low drag and reduced ventilation potential and method for producing the same

NASA Technical Reports Server (NTRS)

Caldwell, Richard A. (Inventor)

1991-01-01

A lift producing device is disclosed which is adapted to be connected to a vehicle to provide lift to the vehicle when the vehicle is moved relative to a first fluid medium having a first density and viscosity and being in contact with a second fluid medium adjacent the vehicle. The second fluid medium has a second fluid density which is different from the first fluid density. The lift producing device comprises opposed first and second major surfaces joined at a longitudinally extending leading edge and at a longitudinally extending trailing edge, with at least a portion of the longitudinally extending leading edge being spaced from the longitudinally extending trailing edge by a predetermined mean chord length. When the vehicle is moved relative to the first fluid medium at a velocity within a range of predetermined velocities, with each of the velocities having a direction inclined from a plane extending through the leading edge and the trailing edge within a predetermined angular range, a region of high pressure is generated in the first fluid medium adjacent the first major surface and a region of low pressure is generated in the first fluid medium adjacent the second major surface. The lift producing device has a cross-sectional shape which will generate a pressure distribution around the device when the vehicle is moved relative to the first fluid medium at a velocity within the range of predetermined velocities such that the first fluid medium exhibits attached laminar flow along the device for a portion of the predetermined mean chord length from the leading edge to the trailing edge and will neither form a laminar separation bubble adjacent the second major surface of the device, nor exhibit turbulent separation adjacent the second major surface for substantially all of the predetermined mean chord length from the leading edge to the trailing edge. The portion along which attached laminar flow is maintained is the longest portion which will still fulfill the flow separation requirements. A method for producing the foil is also disclosed.

Adaptive Acceleration of Visually Evoked Smooth Eye Movements in Mice

PubMed Central

2016-01-01

The optokinetic response (OKR) consists of smooth eye movements following global motion of the visual surround, which suppress image slip on the retina for visual acuity. The effective performance of the OKR is limited to rather slow and low-frequency visual stimuli, although it can be adaptably improved by cerebellum-dependent mechanisms. To better understand circuit mechanisms constraining OKR performance, we monitored how distinct kinematic features of the OKR change over the course of OKR adaptation, and found that eye acceleration at stimulus onset primarily limited OKR performance but could be dramatically potentiated by visual experience. Eye acceleration in the temporal-to-nasal direction depended more on the ipsilateral floccular complex of the cerebellum than did that in the nasal-to-temporal direction. Gaze-holding following the OKR was also modified in parallel with eye-acceleration potentiation. Optogenetic manipulation revealed that synchronous excitation and inhibition of floccular complex Purkinje cells could effectively accelerate eye movements in the nasotemporal and temporonasal directions, respectively. These results collectively delineate multiple motor pathways subserving distinct aspects of the OKR in mice and constrain hypotheses regarding cellular mechanisms of the cerebellum-dependent tuning of movement acceleration. SIGNIFICANCE STATEMENT Although visually evoked smooth eye movements, known as the optokinetic response (OKR), have been studied in various species for decades, circuit mechanisms of oculomotor control and adaptation remain elusive. In the present study, we assessed kinematics of the mouse OKR through the course of adaptation training. Our analyses revealed that eye acceleration at visual-stimulus onset primarily limited working velocity and frequency range of the OKR, yet could be dramatically potentiated during OKR adaptation. Potentiation of eye acceleration exhibited different properties between the nasotemporal and temporonasal OKRs, indicating distinct visuomotor circuits underlying the two. Lesions and optogenetic manipulation of the cerebellum provide constraints on neural circuits mediating visually driven eye acceleration and its adaptation. PMID:27335412

Issues Affecting Cross-Cultural Adaptation of International Graduate Students

ERIC Educational Resources Information Center

Hartshorne, Richard; Baucom, Jennifer

2007-01-01

The purpose of this study was to identify and analyze the adjustment problems encountered by international graduate students enrolled in American universities. Issues of interest included motives for attending graduate school, factors involved in facilitating and constraining the graduate school experience, personality traits that contribute to…

KENNEDY SPACE CENTER, FLA. - An overhead crane in the Space Station Processing Facility lifts the U.S. Node 2 out of its shipping container. The node will be moved to a workstand. The second of three connecting modules on the International Space Station, the Italian-built Node 2 attaches to the end of the U.S. Lab and provides attach locations for the Japanese laboratory, European laboratory, the Centrifuge Accommodation Module and, later, Multipurpose Logistics Modules. It will provide the primary docking location for the Shuttle when a pressurized mating adapter is attached to Node 2. Installation of the module will complete the U.S. Core of the ISS. Node 2 is the designated payload for mission STS-120. No orbiter or launch date has been determined yet.

NASA Image and Video Library

2003-06-03

KENNEDY SPACE CENTER, FLA. - An overhead crane in the Space Station Processing Facility lifts the U.S. Node 2 out of its shipping container. The node will be moved to a workstand. The second of three connecting modules on the International Space Station, the Italian-built Node 2 attaches to the end of the U.S. Lab and provides attach locations for the Japanese laboratory, European laboratory, the Centrifuge Accommodation Module and, later, Multipurpose Logistics Modules. It will provide the primary docking location for the Shuttle when a pressurized mating adapter is attached to Node 2. Installation of the module will complete the U.S. Core of the ISS. Node 2 is the designated payload for mission STS-120. No orbiter or launch date has been determined yet.

Kinematics of flap-bounding flight in the zebra finch over a wide range of speeds

PubMed

Tobalske; Peacock; Dial

1999-07-01

It has been proposed elsewhere that flap-bounding, an intermittent flight style consisting of flapping phases interspersed with flexed-wing bounds, should offer no savings in average mechanical power relative to continuous flapping unless a bird flies 1.2 times faster than its maximum range speed (Vmr). Why do some species use intermittent bounds at speeds slower than 1.2Vmr? The 'fixed-gear hypothesis' suggests that flap-bounding is used to vary mean power output in small birds that are otherwise constrained by muscle physiology and wing anatomy to use a fixed muscle shortening velocity and pattern of wing motion at all flight speeds; the 'body-lift hypothesis' suggests that some weight support during bounds could make flap-bounding flight aerodynamically advantageous in comparison with continuous flapping over most forward flight speeds. To test these predictions, we studied high-speed film recordings (300 Hz) of wing and body motion in zebra finches (Taenopygia guttata, mean mass 13.2 g, N=4) taken as the birds flew in a variable-speed wind tunnel (0-14 m s-1). The zebra finches used flap-bounding flight at all speeds, so their flight style was unique compared with that of birds that facultatively shift from continuous flapping or flap-gliding at slow speeds to flap-bounding at fast speeds. There was a significant effect of flight speed on all measured aspects of wing motion except percentage of the wingbeat spent in downstroke. Changes in angular velocity of the wing indicated that contractile velocity in the pectoralis muscle changed with flight speed, which is not consistent with the fixed-gear hypothesis. Although variation in stroke-plane angle relative to the body, pronation angle of the wing and wing span at mid-upstroke showed that the zebra finch changed within-wingbeat geometries according to speed, a vortex-ring gait with a feathered upstroke appeared to be the only gait used during flapping. In contrast, two small species that use continuous flapping during slow flight (0-4 m s-1) either change wingbeat gait according to flight speed or exhibit more variation in stroke-plane and pronation angles relative to the body. Differences in kinematics among species appear to be related to wing design (aspect ratio, skeletal proportions) rather than to pectoralis muscle fiber composition, indicating that the fixed-gear hypothesis should perhaps be modified to exclude muscle physiology and to emphasize constraints due to wing anatomy. Body lift was produced during bounds at speeds from 4 to 14 m s-1. Maximum body lift was 0.0206 N (15.9 % of body weight) at 10 m s-1; body lift:drag ratio declined with increasing air speed. The aerodynamic function of bounds differed with increasing speed from an emphasis on lift production (4-10 m s-1) to an emphasis on drag reduction with a slight loss in lift (12 and 14 m s-1). From a mathematical model of aerodynamic costs, it appeared that flap-bounding offered the zebra finch an aerodynamic advantage relative to continuous flapping at moderate and fast flight speeds (6-14 m s-1), with body lift augmenting any savings offered solely by flap-bounding at speeds faster than 7.1 m s-1. The percentage of time spent flapping during an intermittent flight cycle decreased with increasing speed, so the mechanical cost of transport was likely to be lowest at faster flight speeds (10-14 m s-1).

Public-private partnerships to improve primary healthcare surgeries: clarifying assumptions about the role of private provider activities.

PubMed

Mudyarabikwa, Oliver; Tobi, Patrick; Regmi, Krishna

2017-07-01

Aim To examine assumptions about public-private partnership (PPP) activities and their role in improving public procurement of primary healthcare surgeries. PPPs were developed to improve the quality of care and patient satisfaction. However, evidence of their effectiveness in delivering health benefits is limited. A qualitative study design was employed. A total of 25 interviews with public sector staff (n=23) and private sector managers (n=2) were conducted to understand their interpretations of assumptions in the activities of private investors and service contractors participating in Local Improvement Finance Trust (LIFT) partnerships. Realist evaluation principles were applied in the data analysis to interpret the findings. Six thematic areas of assumed health benefits were identified: (i) quality improvement; (ii) improved risk management; (iii) reduced procurement costs; (iv) increased efficiency; (v) community involvement; and (vi) sustainable investment. Primary Care Trusts that chose to procure their surgeries through LIFT were expected to support its implementation by providing an environment conducive for the private participants to achieve these benefits. Private participant activities were found to be based on a range of explicit and tacit assumptions perceived helpful in achieving government objectives for LIFT. The success of PPPs depended upon private participants' (i) capacity to assess how PPP assumptions added value to their activities, (ii) effectiveness in interpreting assumptions in their expected activities, and (iii) preparedness to align their business principles to government objectives for PPPs. They risked missing some of the expected benefits because of some factors constraining realization of the assumptions. The ways in which private participants preferred to carry out their activities also influenced the extent to which expected benefits were achieved. Giving more discretion to public than private participants over critical decisions may help in ensuring that assumptions in PPP activities result in outcomes that match the anticipated health benefits.

Co-adaption of tRNA gene copy number and amino acid usage influences translation rates in three life domains

PubMed Central

Du, Meng-Ze; Wei, Wen; Qin, Lei; Liu, Shuo; Zhang, An-Ying; Zhang, Yong; Zhou, Hong

2017-01-01

Abstract Although more and more entangled participants of translation process were realized, how they cooperate and co-determine the final translation efficiency still lacks details. Here, we reasoned that the basic translation components, tRNAs and amino acids should be consistent to maximize the efficiency and minimize the cost. We firstly revealed that 310 out of 410 investigated genomes of three domains had significant co-adaptions between the tRNA gene copy numbers and amino acid compositions, indicating that maximum efficiency constitutes ubiquitous selection pressure on protein translation. Furthermore, fast-growing and larger bacteria are found to have significantly better co-adaption and confirmed the effect of this pressure. Within organism, highly expressed proteins and those connected to acute responses have higher co-adaption intensity. Thus, the better co-adaption probably speeds up the growing of cells through accelerating the translation of special proteins. Experimentally, manipulating the tRNA gene copy number to optimize co-adaption between enhanced green fluorescent protein (EGFP) and tRNA gene set of Escherichia coli indeed lifted the translation rate (speed). Finally, as a newly confirmed translation rate regulating mechanism, the co-adaption reflecting translation rate not only deepens our understanding on translation process but also provides an easy and practicable method to improve protein translation rates and productivity. PMID:28992099

Competitiveness and the Process of Co-adaptation in Team Sport Performance.

PubMed

Passos, Pedro; Araújo, Duarte; Davids, Keith

2016-01-01

An evolutionary psycho-biological perspective on competitiveness dynamics is presented, focusing on continuous behavioral co-adaptations to constraints that arise in performance environments. We suggest that an athlete's behavioral dynamics are constrained by circumstances of competing for the availability of resources, which once obtained offer possibilities for performance success. This defines the influence of the athlete-environment relationship on competitiveness. Constraining factors in performance include proximity to target areas in team sports and the number of other competitors in a location. By pushing the athlete beyond existing limits, competitiveness enhances opportunities for co-adaptation, innovation and creativity, which can lead individuals toward different performance solutions to achieve the same performance goal. Underpinned by an ecological dynamics framework we examine whether competitiveness is a crucial feature to succeed in team sports. Our focus is on intra-team competitiveness, concerning the capacity of individuals within a team to become perceptually attuned to affordances in a given performance context which can increase their likelihood of success. This conceptualization implies a re-consideration of the concept of competitiveness, not as an inherited trait or entity to be acquired, but rather theorizing it as a functional performer-environment relationship that needs to be explored, developed, enhanced and maintained in team games training programs.

Experimental and simulation studies of multivariable adaptive optimization of continuous bioreactors using bilevel forgetting factors.

PubMed

Chang, Y K; Lim, H C

1989-08-20

A multivariable on-line adaptive optimization algorithm using a bilevel forgetting factor method was developed and applied to a continuous baker's yeast culture in simulation and experimental studies to maximize the cellular productivity by manipulating the dilution rate and the temperature. The algorithm showed a good optimization speed and a good adaptability and reoptimization capability. The algorithm was able to stably maintain the process around the optimum point for an extended period of time. Two cases were investigated: an unconstrained and a constrained optimization. In the constrained optimization the ethanol concentration was used as an index for the baking quality of yeast cells. An equality constraint with a quadratic penalty was imposed on the ethanol concentration to keep its level close to a hypothetical "optimum" value. The developed algorithm was experimentally applied to a baker's yeast culture to demonstrate its validity. Only unconstrained optimization was carried out experimentally. A set of tuning parameter values was suggested after evaluating the results from several experimental runs. With those tuning parameter values the optimization took 50-90 h. At the attained steady state the dilution rate was 0.310 h(-1) the temperature 32.8 degrees C, and the cellular productivity 1.50 g/L/h.

Modelling carotid artery adaptations to dynamic alterations in pressure and flow over the cardiac cycle

PubMed Central

Cardamone, L.; Valentín, A.; Eberth, J. F.; Humphrey, J. D.

2010-01-01

Motivated by recent clinical and laboratory findings of important effects of pulsatile pressure and flow on arterial adaptations, we employ and extend an established constrained mixture framework of growth (change in mass) and remodelling (change in structure) to include such dynamical effects. New descriptors of cell and tissue behavior (constitutive relations) are postulated and refined based on new experimental data from a transverse aortic arch banding model in the mouse that increases pulsatile pressure and flow in one carotid artery. In particular, it is shown that there was a need to refine constitutive relations for the active stress generated by smooth muscle, to include both stress- and stress rate-mediated control of the turnover of cells and matrix and to account for a cyclic stress-mediated loss of elastic fibre integrity and decrease in collagen stiffness in order to capture the reported evolution, over 8 weeks, of luminal radius, wall thickness, axial force and in vivo axial stretch of the hypertensive mouse carotid artery. We submit, therefore, that complex aspects of adaptation by elastic arteries can be predicted by constrained mixture models wherein individual constituents are produced or removed at individual rates and to individual extents depending on changes in both stress and stress rate from normal values. PMID:20484365

Regime shifts and panarchies in regional scale social ...

EPA Pesticide Factsheets

In this article we summarize histories of nonlinear, complex interactions among societal, legal, and ecosystem dynamics in six North American water basins, as they respond to changing climate. These case studies were chosen to explore the conditions for emergence of adaptive governance in heavily regulated and developed social-ecological systems nested within a hierarchical governmental system. We summarize resilience assessments conducted in each system to provide a synthesis and reference by the other articles in this special feature. We also present a general framework used to evaluate the interactions between society and ecosystem regimes and the governance regimes chosen to mediate those interactions. The case studies show different ways that adaptive governance may be triggered, facilitated, or constrained by ecological and/or legal processes. The resilience assessments indicate that complex interactions among the governance and ecosystem components of these systems can produce different trajectories, which include patterns of (a) development and stabilization, (b) cycles of crisis and recovery, which includes lurches in adaptation and learning, and (3) periods of innovation, novelty, and transformation. Exploration of cross scale (Panarchy) interactions among levels and sectors of government and society illustrate that they may constrain development trajectories, but may also provide stability during crisis or innovation at smaller scales; create crises,

Constraint shapes convergence in tetrodotoxin-resistant sodium channels of snakes.

PubMed

Feldman, Chris R; Brodie, Edmund D; Brodie, Edmund D; Pfrender, Michael E

2012-03-20

Natural selection often produces convergent changes in unrelated lineages, but the degree to which such adaptations occur via predictable genetic paths is unknown. If only a limited subset of possible mutations is fixed in independent lineages, then it is clear that constraint in the production or function of molecular variants is an important determinant of adaptation. We demonstrate remarkably constrained convergence during the evolution of resistance to the lethal poison, tetrodotoxin, in six snake species representing three distinct lineages from around the globe. Resistance-conferring amino acid substitutions in a voltage-gated sodium channel, Na(v)1.4, are clustered in only two regions of the protein, and a majority of the replacements are confined to the same three positions. The observed changes represent only a small fraction of the experimentally validated mutations known to increase Na(v)1.4 resistance to tetrodotoxin. These results suggest that constraints resulting from functional tradeoffs between ion channel function and toxin resistance led to predictable patterns of evolutionary convergence at the molecular level. Our data are consistent with theoretical predictions and recent microcosm work that suggest a predictable path is followed during an adaptive walk along a mutational landscape, and that natural selection may be frequently constrained to produce similar genetic outcomes even when operating on independent lineages.

Adaptation from restricted geometries: the shell inclination of terrestrial gastropods.

PubMed

Okajima, Ryoko; Chiba, Satoshi

2013-02-01

The adaptations that occur for support and protection can be studied with regard to the optimal structure that balances these objectives with any imposed constraints. The shell inclination of terrestrial gastropods is an appropriate model to address this problem. In this study, we examined how gastropods improve shell angles to well-balanced ones from geometrically constrained shapes. Our geometric analysis and physical analysis showed that constantly coiled shells are constrained from adopting a well-balanced angle; the shell angle of such basic shells tends to increase as the spire index (shell height/width) increases, although the optimum angle for stability is 90° for flat shells and 0° for tall shells. Furthermore, we estimated the influences of the geometric rule and the functional demands on actual shells by measuring the shell angles of both resting and active snails. We found that terrestrial gastropods have shell angles that are suited for balance. The growth lines of the shells indicated that this adaptation depends on the deflection of the last whorl: the apertures of flat shells are deflected downward, whereas those of tall shells are deflected upward. Our observations of active snails demonstrated that the animals hold their shells at better balanced angles than inactive snails. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

Competitiveness and the Process of Co-adaptation in Team Sport Performance

PubMed Central

Passos, Pedro; Araújo, Duarte; Davids, Keith

2016-01-01

An evolutionary psycho-biological perspective on competitiveness dynamics is presented, focusing on continuous behavioral co-adaptations to constraints that arise in performance environments. We suggest that an athlete’s behavioral dynamics are constrained by circumstances of competing for the availability of resources, which once obtained offer possibilities for performance success. This defines the influence of the athlete-environment relationship on competitiveness. Constraining factors in performance include proximity to target areas in team sports and the number of other competitors in a location. By pushing the athlete beyond existing limits, competitiveness enhances opportunities for co-adaptation, innovation and creativity, which can lead individuals toward different performance solutions to achieve the same performance goal. Underpinned by an ecological dynamics framework we examine whether competitiveness is a crucial feature to succeed in team sports. Our focus is on intra-team competitiveness, concerning the capacity of individuals within a team to become perceptually attuned to affordances in a given performance context which can increase their likelihood of success. This conceptualization implies a re-consideration of the concept of competitiveness, not as an inherited trait or entity to be acquired, but rather theorizing it as a functional performer-environment relationship that needs to be explored, developed, enhanced and maintained in team games training programs. PMID:27777565

Highlights of experience with a flexible walled test section in the NASA Langley 0.3-meter transonic cryogenic tunnel

NASA Technical Reports Server (NTRS)

Wolf, Stephen W. D.; Ray, Edward J.

1988-01-01

The unique combination of adaptive wall technology with a contonuous flow cryogenic wind tunnel is described. This powerful combination allows wind tunnel users to carry out 2-D tests at flight Reynolds numbers with wall interference essentially eliminated. Validation testing was conducted to support this claim using well tested symmetrical and cambered airfoils at transonic speeds and high Reynolds numbers. The test section hardware has four solid walls, with the floor and ceiling flexible. The method of adapting/shaping the floor and ceiling to eliminate top and bottom wall interference at its source is outlined. Data comparisons for different size models tested and others in several sophisticated 2-D wind tunnels are made. In addition, the effects of Reynolds number, testing at high lift with associated large flexible wall movements, the uniqueness of the adapted wall shapes, and the effects of sidewall boundary layer control are examined. The 0.3-m TCT is now the most advanced 2-D research facility anywhere.

An adaptable walking-skid for seabed ROV under strong current disturbance

NASA Astrophysics Data System (ADS)

Si, Jianting; Chin, Chengsiong

2014-09-01

This paper proposed a new concept of an adaptable multi-legged skid design for retro-fitting to a remotely-operated vehicle (ROV) during high tidal current underwater pipeline inspection. The sole reliance on propeller-driven propulsion for ROV is replaced with a proposed low cost biomimetic solution in the form of an attachable hexapod walking skid. The advantage of this adaptable walking skid is the high stability in positioning and endurances to strong current on the seabed environment. The computer simulation flow studies using Solidworks Flow Simulation shown that the skid attachment in different compensation postures caused at least four times increase in overall drag, and negative lift forces on the seabed ROV to achieve a better maneuvering and station keeping under the high current condition (from 0.5 m/s to 5.0 m/s). A graphical user interface is designed to interact with the user during robot-in-the-loop testing and kinematics simulation in the pool.

Functional coupling constrains craniofacial diversification in Lake Tanganyika cichlids

PubMed Central

Tsuboi, Masahito; Gonzalez-Voyer, Alejandro; Kolm, Niclas

2015-01-01

Functional coupling, where a single morphological trait performs multiple functions, is a universal feature of organismal design. Theory suggests that functional coupling may constrain the rate of phenotypic evolution, yet empirical tests of this hypothesis are rare. In fish, the evolutionary transition from guarding the eggs on a sandy/rocky substrate (i.e. substrate guarding) to mouthbrooding introduces a novel function to the craniofacial system and offers an ideal opportunity to test the functional coupling hypothesis. Using a combination of geometric morphometrics and a recently developed phylogenetic comparative method, we found that head morphology evolution was 43% faster in substrate guarding species than in mouthbrooding species. Furthermore, for species in which females were solely responsible for mouthbrooding the males had a higher rate of head morphology evolution than in those with bi-parental mouthbrooding. Our results support the hypothesis that adaptations resulting in functional coupling constrain phenotypic evolution. PMID:25948565

Functional coupling constrains craniofacial diversification in Lake Tanganyika cichlids.

PubMed

Tsuboi, Masahito; Gonzalez-Voyer, Alejandro; Kolm, Niclas

2015-05-01

Functional coupling, where a single morphological trait performs multiple functions, is a universal feature of organismal design. Theory suggests that functional coupling may constrain the rate of phenotypic evolution, yet empirical tests of this hypothesis are rare. In fish, the evolutionary transition from guarding the eggs on a sandy/rocky substrate (i.e. substrate guarding) to mouthbrooding introduces a novel function to the craniofacial system and offers an ideal opportunity to test the functional coupling hypothesis. Using a combination of geometric morphometrics and a recently developed phylogenetic comparative method, we found that head morphology evolution was 43% faster in substrate guarding species than in mouthbrooding species. Furthermore, for species in which females were solely responsible for mouthbrooding the males had a higher rate of head morphology evolution than in those with bi-parental mouthbrooding. Our results support the hypothesis that adaptations resulting in functional coupling constrain phenotypic evolution.

NEUTRON SOURCE

DOEpatents

Foster, J.S. Jr.

1960-04-19

A compact electronic device capable of providing short time high density outputs of neutrons is described. The device of the invention includes an evacuated vacuum housing adapted to be supplied with a deuterium, tritium, or other atmosphere and means for establishing an electrical discharge along a path through the gas. An energized solenoid is arranged to constrain the ionized gas (plasma) along the path. An anode bearing adsorbed or adherent target material is arranged to enclose the constrained plasma. To produce neutrons a high voltage is applied from appropriate supply means between the plasma and anode to accelerate ions from the plasma to impinge upcn the target material, e.g., comprising deuterium.

An Evolutionary Analysis of Learned Attention

ERIC Educational Resources Information Center

Hullinger, Richard A.; Kruschke, John K.; Todd, Peter M.

2015-01-01

Humans and many other species selectively attend to stimuli or stimulus dimensions--but why should an animal constrain information input in this way? To investigate the adaptive functions of attention, we used a genetic algorithm to evolve simple connectionist networks that had to make categorization decisions in a variety of environmental…

Adaptation of innate lymphoid cells to nutrient deprivation promotes type 2 barrier immunity

USDA-ARS?s Scientific Manuscript database

Survival of the host relies on the establishment of site-specific barrier defense tailored to constrain pressures imposed by commensal and parasitic exposures. The host is confronted with the additional challenge of maintaining barrier immunity in fluctuating states of dietary availability, yet how ...

Modeling the Components of an Economy as a Complex Adaptive System

DTIC Science & Technology

principles of constrained optimization and fails to see economic variables as part of an interconnected network. While tools for forecasting economic...data sets such as the stock market . This research portrays the stock market as one component of a networked system of economic variables, with the

Financial Management of Canadian Universities: Adaptive Strategies to Fiscal Constraints

ERIC Educational Resources Information Center

Deering, Darren; Sá, Creso M.

2014-01-01

Decreasing government funding and regulated tuition policies have created a financially constrained environment for Canada's universities. The conventional response to such conditions is to cut programme offerings and services in an attempt to lower costs throughout the institution. However, we argue that three Canadian universities have reacted…

Share (And Not) Share Alike: Improving Virtual Team Climate and Decision Performance

ERIC Educational Resources Information Center

Cordes, Sean

2017-01-01

Virtual teams face unique communication and collaboration challenges that impact climate development and performance. First, virtual teams rely on technology mediated communication which can constrain communication. Second, team members lack skill for adapting process to the virtual setting. A collaboration process structure was designed to…

75 FR 33320 - Notice of Issuance of Final Determination Concerning a Lift Unit for an Overhead Patient Lift...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-11

... Determination Concerning a Lift Unit for an Overhead Patient Lift System; Correction AGENCY: U.S. Customs and... origin of a lift unit for an overhead patient lift system. The document contained two errors that this... origin of a lift unit for an overhead patient lift system. This document corrects in the DATES section of...

Uncertainty, learning, and the optimal management of wildlife

USGS Publications Warehouse

Williams, B.K.

2001-01-01

Wildlife management is limited by uncontrolled and often unrecognized environmental variation, by limited capabilities to observe and control animal populations, and by a lack of understanding about the biological processes driving population dynamics. In this paper I describe a comprehensive framework for management that includes multiple models and likelihood values to account for structural uncertainty, along with stochastic factors to account for environmental variation, random sampling, and partial controllability. Adaptive optimization is developed in terms of the optimal control of incompletely understood populations, with the expected value of perfect information measuring the potential for improving control through learning. The framework for optimal adaptive control is generalized by including partial observability and non-adaptive, sample-based updating of model likelihoods. Passive adaptive management is derived as a special case of constrained adaptive optimization, representing a potentially efficient suboptimal alternative that nonetheless accounts for structural uncertainty.

Adaptive Neural Control of Uncertain MIMO Nonlinear Systems With State and Input Constraints.

PubMed

Chen, Ziting; Li, Zhijun; Chen, C L Philip

2017-06-01

An adaptive neural control strategy for multiple input multiple output nonlinear systems with various constraints is presented in this paper. To deal with the nonsymmetric input nonlinearity and the constrained states, the proposed adaptive neural control is combined with the backstepping method, radial basis function neural network, barrier Lyapunov function (BLF), and disturbance observer. By ensuring the boundedness of the BLF of the closed-loop system, it is demonstrated that the output tracking is achieved with all states remaining in the constraint sets and the general assumption on nonsingularity of unknown control coefficient matrices has been eliminated. The constructed adaptive neural control has been rigorously proved that it can guarantee the semiglobally uniformly ultimate boundedness of all signals in the closed-loop system. Finally, the simulation studies on a 2-DOF robotic manipulator system indicate that the designed adaptive control is effective.

Visual adaptation of the perception of "life": animacy is a basic perceptual dimension of faces.

PubMed

Koldewyn, Kami; Hanus, Patricia; Balas, Benjamin

2014-08-01

One critical component of understanding another's mind is the perception of "life" in a face. However, little is known about the cognitive and neural mechanisms underlying this perception of animacy. Here, using a visual adaptation paradigm, we ask whether face animacy is (1) a basic dimension of face perception and (2) supported by a common neural mechanism across distinct face categories defined by age and species. Observers rated the perceived animacy of adult human faces before and after adaptation to (1) adult faces, (2) child faces, and (3) dog faces. When testing the perception of animacy in human faces, we found significant adaptation to both adult and child faces, but not dog faces. We did, however, find significant adaptation when morphed dog images and dog adaptors were used. Thus, animacy perception in faces appears to be a basic dimension of face perception that is species specific but not constrained by age categories.

Magnification bias as a novel probe for primordial magnetic fields

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

Camera, S.; Fedeli, C.; Moscardini, L., E-mail: stefano.camera@tecnico.ulisboa.pt, E-mail: cosimo.fedeli@oabo.inaf.it, E-mail: lauro.moscardini@unibo.it

2014-03-01

In this paper we investigate magnetic fields generated in the early Universe. These fields are important candidates at explaining the origin of astrophysical magnetism observed in galaxies and galaxy clusters, whose genesis is still by and large unclear. Compared to the standard inflationary power spectrum, intermediate to small scales would experience further substantial matter clustering, were a cosmological magnetic field present prior to recombination. As a consequence, the bias and redshift distribution of galaxies would also be modified. Hitherto, primordial magnetic fields (PMFs) have been tested and constrained with a number of cosmological observables, e.g. the cosmic microwave background radiation,more » galaxy clustering and, more recently, weak gravitational lensing. Here, we explore the constraining potential of the density fluctuation bias induced by gravitational lensing magnification onto the galaxy-galaxy angular power spectrum. Such an effect is known as magnification bias. Compared to the usual galaxy clustering approach, magnification bias helps in lifting the pathological degeneracy present amongst power spectrum normalisation and galaxy bias. This is because magnification bias cross-correlates galaxy number density fluctuations of nearby objects with weak lensing distortions of high-redshift sources. Thus, it takes advantage of the gravitational deflection of light, which is insensitive to galaxy bias but powerful in constraining the density fluctuation amplitude. To scrutinise the potentiality of this method, we adopt a deep and wide-field spectroscopic galaxy survey. We show that magnification bias does contain important information on primordial magnetism, which will be useful in combination with galaxy clustering and shear. We find we shall be able to rule out at 95.4% CL amplitudes of PMFs larger than 5 × 10{sup −4} nG for values of the PMF power spectral index n{sub B} ∼ 0.« less

Are interpretations of ancient marine temperatures constrained by the presence of ancient marine organisms?

NASA Technical Reports Server (NTRS)

Valentine, J. W.

1985-01-01

The relationship between marine temperature and marine organisms is investigated. The adaptation of organisms to extreme temperatures is studied; it is observed that chemautotrophic and chemoheterotrophic prokaryotes adapt to 100 C, photoautotrophic prokaryotes to 73 C, and fungi to 60 C. The physiological and molecular factors related to thermal limits in organisms such as enzymes, lipids, or plasma membranes, are examined. Two types of thermal adaptations, resistance and capacity, are detected in organisms. Reasons for species distributions according to temperature barriers are proposed by Read (1967) and Bullock (1955) and are related to enzyme limits. The effects of an organism's composition on thermal stability is analyzed.

Normalized lift: an energy interpretation of the lift coefficient simplifies comparisons of the lifting ability of rotating and flapping surfaces.

PubMed

Burgers, Phillip; Alexander, David E

2012-01-01

For a century, researchers have used the standard lift coefficient C(L) to evaluate the lift, L, generated by fixed wings over an area S against dynamic pressure, ½ρv(2), where v is the effective velocity of the wing. Because the lift coefficient was developed initially for fixed wings in steady flow, its application to other lifting systems requires either simplifying assumptions or complex adjustments as is the case for flapping wings and rotating cylinders.This paper interprets the standard lift coefficient of a fixed wing slightly differently, as the work exerted by the wing on the surrounding flow field (L/ρ·S), compared against the total kinetic energy required for generating said lift, ½v(2). This reinterpreted coefficient, the normalized lift, is derived from the work-energy theorem and compares the lifting capabilities of dissimilar lift systems on a similar energy footing. The normalized lift is the same as the standard lift coefficient for fixed wings, but differs for wings with more complex motions; it also accounts for such complex motions explicitly and without complex modifications or adjustments. We compare the normalized lift with the previously-reported values of lift coefficient for a rotating cylinder in Magnus effect, a bat during hovering and forward flight, and a hovering dipteran.The maximum standard lift coefficient for a fixed wing without flaps in steady flow is around 1.5, yet for a rotating cylinder it may exceed 9.0, a value that implies that a rotating cylinder generates nearly 6 times the maximum lift of a wing. The maximum normalized lift for a rotating cylinder is 1.5. We suggest that the normalized lift can be used to evaluate propellers, rotors, flapping wings of animals and micro air vehicles, and underwater thrust-generating fins in the same way the lift coefficient is currently used to evaluate fixed wings.

Normalized Lift: An Energy Interpretation of the Lift Coefficient Simplifies Comparisons of the Lifting Ability of Rotating and Flapping Surfaces

PubMed Central

Burgers, Phillip; Alexander, David E.

2012-01-01

For a century, researchers have used the standard lift coefficient CL to evaluate the lift, L, generated by fixed wings over an area S against dynamic pressure, ½ρv 2, where v is the effective velocity of the wing. Because the lift coefficient was developed initially for fixed wings in steady flow, its application to other lifting systems requires either simplifying assumptions or complex adjustments as is the case for flapping wings and rotating cylinders. This paper interprets the standard lift coefficient of a fixed wing slightly differently, as the work exerted by the wing on the surrounding flow field (L/ρ·S), compared against the total kinetic energy required for generating said lift, ½v2. This reinterpreted coefficient, the normalized lift, is derived from the work-energy theorem and compares the lifting capabilities of dissimilar lift systems on a similar energy footing. The normalized lift is the same as the standard lift coefficient for fixed wings, but differs for wings with more complex motions; it also accounts for such complex motions explicitly and without complex modifications or adjustments. We compare the normalized lift with the previously-reported values of lift coefficient for a rotating cylinder in Magnus effect, a bat during hovering and forward flight, and a hovering dipteran. The maximum standard lift coefficient for a fixed wing without flaps in steady flow is around 1.5, yet for a rotating cylinder it may exceed 9.0, a value that implies that a rotating cylinder generates nearly 6 times the maximum lift of a wing. The maximum normalized lift for a rotating cylinder is 1.5. We suggest that the normalized lift can be used to evaluate propellers, rotors, flapping wings of animals and micro air vehicles, and underwater thrust-generating fins in the same way the lift coefficient is currently used to evaluate fixed wings. PMID:22629326

Effects of a Belt on Intra-Abdominal Pressure during Weight Lifting.

DTIC Science & Technology

1988-03-01

potentially injurious b compressive forces on spinal discs during lifting. To investigate the effects of a standard lifting belt on lAP and lifting mechanics... injurious compressive forces on spinal discs during lifting. To investigate the effects of a standard lifting belt on IAP and lifting ! mechanics... weightlifting (7,9). Both olympic and power lifters have used lifting belts for many years, yet virtually no research has been reported which examines

Lifting strength in two-person teamwork.

PubMed

Lee, Tzu-Hsien

2016-01-01

This study examined the effects of lifting range, hand-to-toe distance, and lifting direction on single-person lifting strengths and two-person teamwork lifting strengths. Six healthy males and seven healthy females participated in this study. Two-person teamwork lifting strengths were examined in both strength-matched and strength-unmatched groups. Our results showed that lifting strength significantly decreased with increasing lifting range or hand-to-toe distance. However, lifting strengths were not affected by lifting direction. Teamwork lifting strength did not conform to the law of additivity for both strength-matched and strength-unmatched groups. In general, teamwork lifting strength was dictated by the weaker of the two members, implying that weaker members might be exposed to a higher potential danger in teamwork exertions. To avoid such overexertion in teamwork, members with significantly different strength ability should not be assigned to the same team.

Systems design analysis applied to launch vehicle configuration

NASA Technical Reports Server (NTRS)

Ryan, R.; Verderaime, V.

1993-01-01

As emphasis shifts from optimum-performance aerospace systems to least lift-cycle costs, systems designs must seek, adapt, and innovate cost improvement techniques in design through operations. The systems design process of concept, definition, and design was assessed for the types and flow of total quality management techniques that may be applicable in a launch vehicle systems design analysis. Techniques discussed are task ordering, quality leverage, concurrent engineering, Pareto's principle, robustness, quality function deployment, criteria, and others. These cost oriented techniques are as applicable to aerospace systems design analysis as to any large commercial system.

The Vulnerability of Threatened Species: Adaptive Capability and Adaptation Opportunity

PubMed Central

Berry, Pam; Ogawa-Onishi, Yuko; McVey, Andrew

2013-01-01

Global targets to halt the loss of biodiversity have not been met, and there is now an additional Aichi target for preventing the extinction of known threatened species and improving their conservation status. Climate change increasingly needs to be factored in to these, and thus there is a need to identify the extent to which it could increase species vulnerability. This paper uses the exposure, sensitivity, and adaptive capacity framework to assess the vulnerability of a selection of WWF global priority large mammals and marine species to climate change. However, it divides adaptive capacity into adaptive capability and adaptation opportunity, in order to identify whether adaptation is more constrained by the biology of the species or by its environmental setting. Lack of evidence makes it difficult to apply the framework consistently across the species, but it was found that, particularly for the terrestrial mammals, adaptation opportunities seems to be the greater constraint. This framework and analysis could be used by conservationists and those wishing to enhance the resilience of species to climate change. PMID:24833051

Failure of Anisotropic Unstructured Mesh Adaption Based on Multidimensional Residual Minimization

NASA Technical Reports Server (NTRS)

Wood, William A.; Kleb, William L.

2003-01-01

An automated anisotropic unstructured mesh adaptation strategy is proposed, implemented, and assessed for the discretization of viscous flows. The adaption criteria is based upon the minimization of the residual fluctuations of a multidimensional upwind viscous flow solver. For scalar advection, this adaption strategy has been shown to use fewer grid points than gradient based adaption, naturally aligning mesh edges with discontinuities and characteristic lines. The adaption utilizes a compact stencil and is local in scope, with four fundamental operations: point insertion, point deletion, edge swapping, and nodal displacement. Evaluation of the solution-adaptive strategy is performed for a two-dimensional blunt body laminar wind tunnel case at Mach 10. The results demonstrate that the strategy suffers from a lack of robustness, particularly with regard to alignment of the bow shock in the vicinity of the stagnation streamline. In general, constraining the adaption to such a degree as to maintain robustness results in negligible improvement to the solution. Because the present method fails to consistently or significantly improve the flow solution, it is rejected in favor of simple uniform mesh refinement.

Unique aspects of competitive weightlifting: performance, training and physiology.

PubMed

Storey, Adam; Smith, Heather K

2012-09-01

Weightlifting is a dynamic strength and power sport in which two, multijoint, whole-body lifts are performed in competition; the snatch and clean and jerk. During the performance of these lifts, weightlifters have achieved some of the highest absolute and relative peak power outputs reported in the literature. The training structure of competitive weightlifters is characterized by the frequent use of high-intensity resistance exercise movements. Varied coaching and training philosophies currently exist around the world and further research is required to substantiate the best type of training programme for male and female weightlifters of various age groups. As competitive weightlifting is contested over eight male and seven female body weight categories, the anthropometric characteristics of the athletes widely ranges. The body compositions of weightlifters are similar to that of athletes of comparable body mass in other strength and power sports. However, the shorter height and limb lengths of weightlifters provide mechanical advantages when lifting heavy loads by reducing the mechanical torque and the vertical distance that the barbell must be displaced. Furthermore, the shorter body dimensions coincide with a greater mean skeletal muscle cross-sectional area that is advantageous to weightlifting performance. Weightlifting training induces a high metabolic cost. Although dietary records demonstrate that weightlifters typically meet their required daily energy intake, weightlifters have been shown to over consume protein and fat at the expense of adequate carbohydrate. The resulting macronutrient imbalance may not yield optimal performance gains. Cross-sectional data suggest that weightlifting training induces type IIX to IIA fibre-type transformation. Furthermore, weightlifters exhibit hypertrophy of type II fibres that is advantageous to weightlifting performance and maximal force production. As such, the isometric peak force and contractile rate of force development of weightlifters is ~15-20% and ~13-16% greater, respectively, than in other strength and power athletes. In addition, weightlifting training has been shown to reduce the typical sex-related difference in the expression of neuromuscular strength and power. However, this apparent sex-related difference appears to be augmented with increasing adult age demonstrating that women undergo a greater age-related decline in muscle shortening velocity and peak power when compared with men. Weightlifting training and competition has been shown to induce significant structural and functional adaptations of the cardiovascular system. The collective evidence shows that these adaptations are physiological as opposed to pathological. Finally, the acute exercise-induced testosterone, cortisol and growth hormone responses of weightlifters have similarities to that of following conventional strength and hypertrophy protocols involving large muscle mass exercises. The routine assessment of the basal testosterone : cortisol ratio may be beneficial when attempting to quantify the adaptive responses to weightlifting training. As competitive weightlifting is becoming increasingly popular around the world, further research addressing the physiological responses and adaptations of female weightlifters and younger (i.e. ≤17 years of age) and older (i.e. ≥35 years of age) weightlifters of both sexes is required.

An Experimental Comparison of Similarity Assessment Measures for 3D Models on Constrained Surface Deformation

NASA Astrophysics Data System (ADS)

Quan, Lulin; Yang, Zhixin

2010-05-01

To address the issues in the area of design customization, this paper expressed the specification and application of the constrained surface deformation, and reported the experimental performance comparison of three prevail effective similarity assessment algorithms on constrained surface deformation domain. Constrained surface deformation becomes a promising method that supports for various downstream applications of customized design. Similarity assessment is regarded as the key technology for inspecting the success of new design via measuring the difference level between the deformed new design and the initial sample model, and indicating whether the difference level is within the limitation. According to our theoretical analysis and pre-experiments, three similarity assessment algorithms are suitable for this domain, including shape histogram based method, skeleton based method, and U system moment based method. We analyze their basic functions and implementation methodologies in detail, and do a series of experiments on various situations to test their accuracy and efficiency using precision-recall diagram. Shoe model is chosen as an industrial example for the experiments. It shows that shape histogram based method gained an optimal performance in comparison. Based on the result, we proposed a novel approach that integrating surface constrains and shape histogram description with adaptive weighting method, which emphasize the role of constrains during the assessment. The limited initial experimental result demonstrated that our algorithm outperforms other three algorithms. A clear direction for future development is also drawn at the end of the paper.

Finite Time Control Design for Bilateral Teleoperation System With Position Synchronization Error Constrained.

PubMed

Yang, Yana; Hua, Changchun; Guan, Xinping

2016-03-01

Due to the cognitive limitations of the human operator and lack of complete information about the remote environment, the work performance of such teleoperation systems cannot be guaranteed in most cases. However, some practical tasks conducted by the teleoperation system require high performances, such as tele-surgery needs satisfactory high speed and more precision control results to guarantee patient' health status. To obtain some satisfactory performances, the error constrained control is employed by applying the barrier Lyapunov function (BLF). With the constrained synchronization errors, some high performances, such as, high convergence speed, small overshoot, and an arbitrarily predefined small residual constrained synchronization error can be achieved simultaneously. Nevertheless, like many classical control schemes only the asymptotic/exponential convergence, i.e., the synchronization errors converge to zero as time goes infinity can be achieved with the error constrained control. It is clear that finite time convergence is more desirable. To obtain a finite-time synchronization performance, the terminal sliding mode (TSM)-based finite time control method is developed for teleoperation system with position error constrained in this paper. First, a new nonsingular fast terminal sliding mode (NFTSM) surface with new transformed synchronization errors is proposed. Second, adaptive neural network system is applied for dealing with the system uncertainties and the external disturbances. Third, the BLF is applied to prove the stability and the nonviolation of the synchronization errors constraints. Finally, some comparisons are conducted in simulation and experiment results are also presented to show the effectiveness of the proposed method.

Three-dimensional motion analysis of the lumbar spine during "free squat" weight lift training.

PubMed

Walsh, James C; Quinlan, John F; Stapleton, Robert; FitzPatrick, David P; McCormack, Damian

2007-06-01

Heavy weight lifting using a squat bar is a commonly used athletic training exercise. Previous in vivo motion studies have concentrated on lifting of everyday objects and not on the vastly increased loads that athletes subject themselves to when performing this exercise. Athletes significantly alter their lumbar spinal motion when performing squat lifting at heavy weights. Controlled laboratory study. Forty-eight athletes (28 men, 20 women) performed 6 lifts at 40% maximum, 4 lifts at 60% maximum, and 2 lifts at 80% maximum. The Zebris 3D motion analysis system was used to measure lumbar spine motion. Exercise was performed as a "free" squat and repeated with a weight lifting support belt. Data obtained were analyzed using SAS. A significant decrease (P < .05) was seen in flexion in all groups studied when lifting at 40% maximum compared with lifting at 60% and 80% of maximum lift. Flexion from calibrated 0 point ranged from 24.7 degrees (40% group) to 6.8 degrees (80% group). A significant increase (P < .05) was seen in extension when lifting at 40% maximum was compared with lifting at 60% and 80% maximum lift. Extension from calibrated 0 point ranged from -1.5 degrees (40% group) to -20.3 degrees (80% group). No statistically significant difference was found between motion seen when exercise was performed as a free squat or when lifting using a support belt in any of the groups studied. Weight lifting using a squat bar causes athletes to significantly hyperextend their lumbar spines at heavier weights. The use of a weight lifting support belt does not significantly alter spinal motion during lifting.

Does team lifting increase the variability in peak lumbar compression in ironworkers?

PubMed

Faber, Gert; Visser, Steven; van der Molen, Henk F; Kuijer, P Paul F M; Hoozemans, Marco J M; Van Dieën, Jaap H; Frings-Dresen, Monique H W

2012-01-01

Ironworkers frequently perform heavy lifting tasks in teams of two or four workers. Team lifting could potentially lead to a higher variation in peak lumbar compression forces than lifts performed by one worker, resulting in higher maximal peak lumbar compression forces. This study compared single-worker lifts (25-kg, iron bar) to two-worker lifts (50-kg, two iron bars) and to four-worker lifts (100-kg, iron lattice). Inverse dynamics was used to calculate peak lumbar compression forces. To assess the variability in peak lumbar loading, all three lifting tasks were performed six times. Results showed that the variability in peak lumbar loading was somewhat higher in the team lifts compared to the single-worker lifts. However, despite this increased variability, team lifts did not result in larger maximum peak lumbar compression forces. Therefore, it was concluded that, from a biomechanical point of view, team lifting does not result in an additional risk for low back complaints in ironworkers.

75 FR 31803 - Notice of Issuance of Final Determination Concerning a Lift Unit for an Overhead Patient Lift System

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-04

... Determination Concerning a Lift Unit for an Overhead Patient Lift System AGENCY: U.S. Customs and Border... concerning the country of origin of a lift unit for an overhead patient lift system. Based upon the facts presented, CBP has concluded in the final determination that Sweden is the country of origin of the lift...

The hybrid assistive limb (HAL) for Care Support successfully reduced lumbar load in repetitive lifting movements.

PubMed

Miura, Kousei; Kadone, Hideki; Koda, Masao; Abe, Tetsuya; Kumagai, Hiroshi; Nagashima, Katsuya; Mataki, Kentaro; Fujii, Kengo; Noguchi, Hiroshi; Funayama, Toru; Kawamoto, Hiroaki; Sankai, Yoshiyuki; Yamazaki, Masashi

2018-05-03

Work-related low back pain is a serious socioeconomic problem. This study examined whether HAL for Care Support, which is a newly developed wearable robot, would decrease lumbar fatigue and improve lifting performance during repetitive lifting movements. Eighteen healthy volunteers (11 men, 7 women) performed repetitive stoop lifting movements of a cardboard box weighing 12 kg as many times as possible. The first lifting trial was executed without HAL for Care Support, and the second was with it. We evaluated the VAS of lumbar fatigue as the lumbar load and the number of lifts and the lifting time as lifting performance. Without HAL for Care Support, the mean VAS of lumbar fatigue, the number of lifts and lifting time were 68 mm, 60 and 230 s; with HAL for Care Support, they were 51 mm, 87 and 332 s, respectively. Both lifting performance measures were significantly improved by using HAL for Care Support (Fig. 2). A power analysis showed that there was sufficient statistical power for the VAS of lumbar fatigue (0.99), the number of lifts (0.92), and lifting time (0.93). All participants performed their repetitive lifting trials safely. There were no adverse events caused by using HAL for Care Support. In conclusion, the HAL for Care Support can decrease lumbar load and improve the lifting performance during repetitive stoop lifting movements in healthy adults. Copyright © 2018. Published by Elsevier Ltd.

A metronome for controlling the mean velocity during the bench press exercise.

PubMed

Moras, Gerard; Rodríguez-Jiménez, Sergio; Busquets, Albert; Tous-Fajardo, Julio; Pozzo, Marco; Mujika, Iñigo

2009-05-01

Lifting velocity may have a great impact on strength training-induced adaptations. The purpose of this study was to validate a method including a metronome and a measurement tape as inexpensive tools for the estimation of mean lifting velocity during the bench press exercise. Fifteen subjects participated in this study. After determining their one repetition maximum (1RM) load, we estimated the maximum metronome rhythm (R) that each subject could maintain in the concentric phase for loads of 40 and 60% of 1RM. To estimate R, the 3 repetitions with highest concentric power, as measured by means of a linear encoder, were selected, and their average duration was calculated and converted to lifting rhythm in beats per minute (bpm) for each subject. The range of motion was measured using a regular tape and kept constant during all exercises. Subjects were instructed to begin with the barbell at arm lengths and lower it in correspondence with the metronome beep. They subsequently performed 5 repetitions at 3 different rhythms relative to R (50, 70, and 90% R) for each training load (40 and 60% of 1RM). A linear encoder was attached to the bar and used as a criterion to measure the vertical displacement over time. For each rhythm, the mean velocity was calculated with the metronome (time) and the reference distance and compared with that recorded by the linear encoder. The SEM for velocity between both testing methods ranged from 0.02 to 0.05 m.s (coefficient of variation, 4.0-6.4%; Pearson's correlation, 0.8-0.95). The present results showed that the use of a metronome and a measurement tape may be a valid method to estimate the mean velocity of execution during the bench press exercise. This simple method could help coaches and athletes achieve their strength training goals, which are partly determined by lifting velocity.

Efficiency of lift production in flapping and gliding flight of swifts.

PubMed

Henningsson, Per; Hedenström, Anders; Bomphrey, Richard J

2014-01-01

Many flying animals use both flapping and gliding flight as part of their routine behaviour. These two kinematic patterns impose conflicting requirements on wing design for aerodynamic efficiency and, in the absence of extreme morphing, wings cannot be optimised for both flight modes. In gliding flight, the wing experiences uniform incident flow and the optimal shape is a high aspect ratio wing with an elliptical planform. In flapping flight, on the other hand, the wing tip travels faster than the root, creating a spanwise velocity gradient. To compensate, the optimal wing shape should taper towards the tip (reducing the local chord) and/or twist from root to tip (reducing local angle of attack). We hypothesised that, if a bird is limited in its ability to morph its wings and adapt its wing shape to suit both flight modes, then a preference towards flapping flight optimization will be expected since this is the most energetically demanding flight mode. We tested this by studying a well-known flap-gliding species, the common swift, by measuring the wakes generated by two birds, one in gliding and one in flapping flight in a wind tunnel. We calculated span efficiency, the efficiency of lift production, and found that the flapping swift had consistently higher span efficiency than the gliding swift. This supports our hypothesis and suggests that even though swifts have been shown previously to increase their lift-to-drag ratio substantially when gliding, the wing morphology is tuned to be more aerodynamically efficient in generating lift during flapping. Since body drag can be assumed to be similar for both flapping and gliding, it follows that the higher total drag in flapping flight compared with gliding flight is primarily a consequence of an increase in wing profile drag due to the flapping motion, exceeding the reduction in induced drag.

Efficiency of Lift Production in Flapping and Gliding Flight of Swifts

PubMed Central

Henningsson, Per; Hedenström, Anders; Bomphrey, Richard J.

2014-01-01

Many flying animals use both flapping and gliding flight as part of their routine behaviour. These two kinematic patterns impose conflicting requirements on wing design for aerodynamic efficiency and, in the absence of extreme morphing, wings cannot be optimised for both flight modes. In gliding flight, the wing experiences uniform incident flow and the optimal shape is a high aspect ratio wing with an elliptical planform. In flapping flight, on the other hand, the wing tip travels faster than the root, creating a spanwise velocity gradient. To compensate, the optimal wing shape should taper towards the tip (reducing the local chord) and/or twist from root to tip (reducing local angle of attack). We hypothesised that, if a bird is limited in its ability to morph its wings and adapt its wing shape to suit both flight modes, then a preference towards flapping flight optimization will be expected since this is the most energetically demanding flight mode. We tested this by studying a well-known flap-gliding species, the common swift, by measuring the wakes generated by two birds, one in gliding and one in flapping flight in a wind tunnel. We calculated span efficiency, the efficiency of lift production, and found that the flapping swift had consistently higher span efficiency than the gliding swift. This supports our hypothesis and suggests that even though swifts have been shown previously to increase their lift-to-drag ratio substantially when gliding, the wing morphology is tuned to be more aerodynamically efficient in generating lift during flapping. Since body drag can be assumed to be similar for both flapping and gliding, it follows that the higher total drag in flapping flight compared with gliding flight is primarily a consequence of an increase in wing profile drag due to the flapping motion, exceeding the reduction in induced drag. PMID:24587260

Computational fluid dynamics challenges for hybrid air vehicle applications

NASA Astrophysics Data System (ADS)

Carrin, M.; Biava, M.; Steijl, R.; Barakos, G. N.; Stewart, D.

2017-06-01

This paper begins by comparing turbulence models for the prediction of hybrid air vehicle (HAV) flows. A 6 : 1 prolate spheroid is employed for validation of the computational fluid dynamics (CFD) method. An analysis of turbulent quantities is presented and the Shear Stress Transport (SST) k-ω model is compared against a k-ω Explicit Algebraic Stress model (EASM) within the unsteady Reynolds-Averaged Navier-Stokes (RANS) framework. Further comparisons involve Scale Adaptative Simulation models and a local transition transport model. The results show that the flow around the vehicle at low pitch angles is sensitive to transition effects. At high pitch angles, the vortices generated on the suction side provide substantial lift augmentation and are better resolved by EASMs. The validated CFD method is employed for the flow around a shape similar to the Airlander aircraft of Hybrid Air Vehicles Ltd. The sensitivity of the transition location to the Reynolds number is demonstrated and the role of each vehicle£s component is analyzed. It was found that the ¦ns contributed the most to increase the lift and drag.

Adaptive management of ecosystem services across different land use regimes.

PubMed

Ruhl, J B

2016-12-01

Using adaptive management to manage desired flows of ecosystem services may seem on the surface to be a good fit, but many social, economic, environmental, legal, and political factors influence how good a fit. One strongly influential factor is the land use regime within which the profile of ecosystem services is being managed. Shaped largely by legal mandates, market forces, and social and cultural practices, different land use regimes present different opportunities for and constraints on goals for ecosystem services and pose different decision making environments. Even where all other conditions appear amenable to using adaptive management, therefore, it is essential to consider the constraining (or liberating) effects of different land use regimes when deciding whether to adopt adaptive management to achieve those goals and, if so, how to implement it. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mechanisms of force and power production in unsteady ricochetal brachiation.

PubMed

Usherwood, James R; Larson, Susan G; Bertram, John E A

2003-04-01

Brachiators travel by swinging beneath handholds, and it is not obvious how these animals manage to accelerate and decelerate in a horizontal direction, especially when moving rapidly. Most previous analyses focused on brachiation in highly constrained laboratory conditions that induced steady-state locomotion. Emerging understanding of brachiation suggests that much of gibbon locomotory behavior and morphology must be considered within the context of the complexities of the natural environment: the forest canopy is three-dimensional, with high variation in handhold availability and properties. The goal of this paper is to quantify the active mechanisms by which gibbons can dynamically control their velocity. Force production and kinematics were analyzed from a white-handed gibbon Hylabates lar during ricochetal brachiation. Both the mechanisms of force production and power input may be inferred for accelerating and decelerating brachiation by combining force data with kinematics. Examples of steady-state, accelerating, and decelerating ricochetal brachiation are highlighted. Gibbons are able to produce net horizontal impulses by releasing early (resulting in a loss of potential energy, but an accelerating horizontal impulse) or delaying release (associated with an increase in potential energy, and a decelerating horizontal impulse). Torque about the shoulder, leg-lifting (or dropping), and elbow flexing (or straightening) are discussed as potential mechanisms for controlling energy within the brachiating system. Of these possibilities, leg-lifting and arm-flexing were observed as mechanisms of adding mechanical energy. Net energy loss, and substantial torques about the shoulder, were not observed. Copyright 2003 Wiley-Liss, Inc.

Postfire logging in riparian areas.

Treesearch

Gordon H. Reeves; Peter A. Bisson; Bruce E. Rieman; Lee E. Benda

2006-01-01

We reviewed the behavior of wildfire in riparian zones, primarily in the western United States, and the potential ecological consequences of postfire logging. Fire behavior in riparian zones is complex, but many aquatic and riparian organisms exhibit a suite of adaptations that allow relatively rapid recovery after fire. Unless constrained by other factors, fish tend...

Information Integration in Multiple Cue Judgment: A Division of Labor Hypothesis

ERIC Educational Resources Information Center

Juslin, Peter; Karlsson, Linnea; Olsson, Henrik

2008-01-01

There is considerable evidence that judgment is constrained to additive integration of information. The authors propose an explanation of why serial and additive cognitive integration can produce accurate multiple cue judgment both in additive and non-additive environments in terms of an adaptive division of labor between multiple representations.…

Constrained Adaptive Beamforming for Improved Contrast in Breast Ultrasound

DTIC Science & Technology

2008-06-01

Medical Imaging 2007: Ultrasonic Imaging and Signal Processing Proceedings, vol. 6513, San Diego , CA, Feb. 18, 2007. 12. Guenther, D.A., Walker...Transactions on, vol. 6, pp. 185-192, 1987. [23] A. P. Schachat, R. P. Murphy, and A. Patz, Medical Retina, vol. 2, 1 ed. St. Louis: The C. V. Mosby

Finite-horizon control-constrained nonlinear optimal control using single network adaptive critics.

PubMed

Heydari, Ali; Balakrishnan, Sivasubramanya N

2013-01-01

To synthesize fixed-final-time control-constrained optimal controllers for discrete-time nonlinear control-affine systems, a single neural network (NN)-based controller called the Finite-horizon Single Network Adaptive Critic is developed in this paper. Inputs to the NN are the current system states and the time-to-go, and the network outputs are the costates that are used to compute optimal feedback control. Control constraints are handled through a nonquadratic cost function. Convergence proofs of: 1) the reinforcement learning-based training method to the optimal solution; 2) the training error; and 3) the network weights are provided. The resulting controller is shown to solve the associated time-varying Hamilton-Jacobi-Bellman equation and provide the fixed-final-time optimal solution. Performance of the new synthesis technique is demonstrated through different examples including an attitude control problem wherein a rigid spacecraft performs a finite-time attitude maneuver subject to control bounds. The new formulation has great potential for implementation since it consists of only one NN with single set of weights and it provides comprehensive feedback solutions online, though it is trained offline.

Caste load and the evolution of reproductive skew.

PubMed

Holman, Luke

2014-01-01

Reproductive skew theory seeks to explain how reproduction is divided among group members in animal societies. Existing theory is framed almost entirely in terms of selection, though nonadaptive processes must also play some role in the evolution of reproductive skew. Here I propose that a genetic correlation between helper fecundity and breeder fecundity may frequently constrain the evolution of reproductive skew. This constraint is part of a wider phenomenon that I term "caste load," which is defined as the decline in mean fitness caused by caste-specific selection pressures, that is, differential selection on breeding and nonbreeding individuals. I elaborate the caste load hypothesis using quantitative and population genetic arguments and individual-based simulations. Although selection can sometimes erode genetic correlations and resolve caste load, this may be constrained when mutations have similar pleiotropic effects on breeder and helper traits. I document evidence for caste load, identify putative genomic adaptations to it, and suggest future research directions. The models highlight the value of considering adaptation within the boundaries imposed by genetic architecture and incidentally reaffirm that monogamy promotes the evolutionary transition to eusociality.

Adaptive Multi-Agent Systems for Constrained Optimization

NASA Technical Reports Server (NTRS)

Macready, William; Bieniawski, Stefan; Wolpert, David H.

2004-01-01

Product Distribution (PD) theory is a new framework for analyzing and controlling distributed systems. Here we demonstrate its use for distributed stochastic optimization. First we review one motivation of PD theory, as the information-theoretic extension of conventional full-rationality game theory to the case of bounded rational agents. In this extension the equilibrium of the game is the optimizer of a Lagrangian of the (probability distribution of) the joint state of the agents. When the game in question is a team game with constraints, that equilibrium optimizes the expected value of the team game utility, subject to those constraints. The updating of the Lagrange parameters in the Lagrangian can be viewed as a form of automated annealing, that focuses the MAS more and more on the optimal pure strategy. This provides a simple way to map the solution of any constrained optimization problem onto the equilibrium of a Multi-Agent System (MAS). We present computer experiments involving both the Queen s problem and K-SAT validating the predictions of PD theory and its use for off-the-shelf distributed adaptive optimization.

Finite-horizon differential games for missile-target interception system using adaptive dynamic programming with input constraints

NASA Astrophysics Data System (ADS)

Sun, Jingliang; Liu, Chunsheng

2018-01-01

In this paper, the problem of intercepting a manoeuvring target within a fixed final time is posed in a non-linear constrained zero-sum differential game framework. The Nash equilibrium solution is found by solving the finite-horizon constrained differential game problem via adaptive dynamic programming technique. Besides, a suitable non-quadratic functional is utilised to encode the control constraints into a differential game problem. The single critic network with constant weights and time-varying activation functions is constructed to approximate the solution of associated time-varying Hamilton-Jacobi-Isaacs equation online. To properly satisfy the terminal constraint, an additional error term is incorporated in a novel weight-updating law such that the terminal constraint error is also minimised over time. By utilising Lyapunov's direct method, the closed-loop differential game system and the estimation weight error of the critic network are proved to be uniformly ultimately bounded. Finally, the effectiveness of the proposed method is demonstrated by using a simple non-linear system and a non-linear missile-target interception system, assuming first-order dynamics for the interceptor and target.

NASA Hardware Heads to Kennedy For Flight Preparations

NASA Image and Video Library

2018-01-24

The Orion stage adapter will be part of the first integrated flight of NASA's heavy-lift rocket, the Space Launch System, and the Orion spacecraft. The adapter, approximately 5 feet tall and 18 feet in diameter, was designed and built at NASA's Marshall Space Flight Center in Huntsville, Alabama, with advanced friction stir welding technology. It will connect the SLS interim cryogenic propulsion stage to Orion on the first flight that will help engineers check out and verify the agency's new deep-space exploration systems. Inside the adapter, engineers installed special brackets and cabling for the 13 CubeSats that will fly as secondary payloads. The Cubesats are boot-box-sized science and technology investigations that will help pave the way for future human exploration in deep space. The Orion stage adapter flight article recently finished major testing of the avionics system that will deploy the CubeSats. Technicians at NASA's Kennedy Space Center, Florida, will install the secondary payloads and engineers will examine the hardware before it is stacked on the interim cryogenic propulsion stage in the Vehicle Assembly Building prior to launch. For more information about SLS hardware, visit nasa.gov/sls.

Adaptive wing and flow control technology

NASA Astrophysics Data System (ADS)

Stanewsky, E.

2001-10-01

The development of the boundary layer and the interaction of the boundary layer with the outer “inviscid” flow field, exacerbated at high speed by the occurrence of shock waves, essentially determine the performance boundaries of high-speed flight. Furthermore, flight and freestream conditions may change considerably during an aircraft mission while the aircraft itself is only designed for multiple but fixed design points thus impairing overall performance. Consequently, flow and boundary layer control and adaptive wing technology may have revolutionary new benefits for take-off, landing and cruise operating conditions for many aircraft by enabling real-time effective geometry optimization relative to the flight conditions. In this paper we will consider various conventional and novel means of boundary layer and flow control applied to moderate-to-large aspect ratio wings, delta wings and bodies with the specific objectives of drag reduction, lift enhancement, separation suppression and the improvement of air-vehicle control effectiveness. In addition, adaptive wing concepts of varying complexity and corresponding aerodynamic performance gains will be discussed, also giving some examples of possible structural realizations. Furthermore, penalties associated with the implementation of control and adaptation mechanisms into actual aircraft will be addressed. Note that the present contribution is rather application oriented.

Development of a Real Time Sparse Non-Negative Matrix Factorization Module for Cochlear Implants by Using xPC Target

PubMed Central

Hu, Hongmei; Krasoulis, Agamemnon; Lutman, Mark; Bleeck, Stefan

2013-01-01

Cochlear implants (CIS) require efficient speech processing to maximize information transmission to the brain, especially in noise. A novel CI processing strategy was proposed in our previous studies, in which sparsity-constrained non-negative matrix factorization (NMF) was applied to the envelope matrix in order to improve the CI performance in noisy environments. It showed that the algorithm needs to be adaptive, rather than fixed, in order to adjust to acoustical conditions and individual characteristics. Here, we explore the benefit of a system that allows the user to adjust the signal processing in real time according to their individual listening needs and their individual hearing capabilities. In this system, which is based on MATLAB®, SIMULINK® and the xPC Target™ environment, the input/outupt (I/O) boards are interfaced between the SIMULINK blocks and the CI stimulation system, such that the output can be controlled successfully in the manner of a hardware-in-the-loop (HIL) simulation, hence offering a convenient way to implement a real time signal processing module that does not require any low level language. The sparsity constrained parameter of the algorithm was adapted online subjectively during an experiment with normal-hearing subjects and noise vocoded speech simulation. Results show that subjects chose different parameter values according to their own intelligibility preferences, indicating that adaptive real time algorithms are beneficial to fully explore subjective preferences. We conclude that the adaptive real time systems are beneficial for the experimental design, and such systems allow one to conduct psychophysical experiments with high ecological validity. PMID:24129021

Development of a real time sparse non-negative matrix factorization module for cochlear implants by using xPC target.

PubMed

Hu, Hongmei; Krasoulis, Agamemnon; Lutman, Mark; Bleeck, Stefan

2013-10-14

Cochlear implants (CIs) require efficient speech processing to maximize information transmission to the brain, especially in noise. A novel CI processing strategy was proposed in our previous studies, in which sparsity-constrained non-negative matrix factorization (NMF) was applied to the envelope matrix in order to improve the CI performance in noisy environments. It showed that the algorithm needs to be adaptive, rather than fixed, in order to adjust to acoustical conditions and individual characteristics. Here, we explore the benefit of a system that allows the user to adjust the signal processing in real time according to their individual listening needs and their individual hearing capabilities. In this system, which is based on MATLAB®, SIMULINK® and the xPC Target™ environment, the input/outupt (I/O) boards are interfaced between the SIMULINK blocks and the CI stimulation system, such that the output can be controlled successfully in the manner of a hardware-in-the-loop (HIL) simulation, hence offering a convenient way to implement a real time signal processing module that does not require any low level language. The sparsity constrained parameter of the algorithm was adapted online subjectively during an experiment with normal-hearing subjects and noise vocoded speech simulation. Results show that subjects chose different parameter values according to their own intelligibility preferences, indicating that adaptive real time algorithms are beneficial to fully explore subjective preferences. We conclude that the adaptive real time systems are beneficial for the experimental design, and such systems allow one to conduct psychophysical experiments with high ecological validity.

University of Minnesota Duluth Engineering Design Challenge

DTIC Science & Technology

2015-03-23

on overall weight, size, lifting capacity, and ease of transporting. Many initial designs were considered including fire hose lift bags, hydraulic...Many initial designs were considered including fire hose lift bags, hydraulic lifts, a scissor lift, a spring loaded pawl tri-pod, and a pulley lift...26 Fire Hose

Musculoskeletal pain among critical-care nurses by availability and use of patient lifting equipment: an analysis of cross-sectional survey data.

PubMed

Lee, Soo-Jeong; Faucett, Julia; Gillen, Marion; Krause, Niklas

2013-12-01

Patient handling is a major risk factor for musculoskeletal injuries among nurses. Lifting equipment is a main component of safe patient handling programs that aim to prevent musculoskeletal injury. However, the actual levels of lift availability and usage are far from optimal. To examine the effect of patient lifting equipment on musculoskeletal pain by level of lift availability and lift use among critical-care nurses. A cross-sectional postal survey of a random sample of 361 critical-care nurses in the United States. The survey collected data on low-back, neck, and shoulder pain, lift availability, lift use, physical and psychosocial job factors, and sociodemographics. Musculoskeletal pain was assessed by three types of measures: any pain, work-related pain, and major pain. Multivariable logistic regressions were used to examine the associations between musculoskeletal pain and lift variables, controlling for demographic and job factors. Less than half (46%) of respondents reported that their employer provided lifts. Of 168 nurses who had lifts in their workplace, the level of lift availability was high for 59.5%, medium for 25.0%, and low for 13.7%; the level of lift use was high for 32.1%, medium for 31.5%, and low for 31.5%. Significant associations were found between lift availability and work-related low-back and shoulder pain. Compared to nurses without lifts, nurses reporting high-level lift availability were half as likely to have work-related low-back pain (OR=0.50, 95% CI 0.26-0.96) and nurses reporting medium-level lift availability were 3.6 times less likely to have work-related shoulder pain (OR=0.28, 95% CI 0.09-0.91). With respect to lift use, work-related shoulder pain was three times less common among nurses reporting medium-level use (OR=0.33, 95% CI 0.12-0.93); any neck pain was three times more common among nurses reporting low-level use (OR=3.13, 95% CI 1.19-8.28). Greater availability and use of lifts were associated with less musculoskeletal pain among critical-care nurses. These findings suggest that for lift interventions to be effective, lifts must be readily available when needed and barriers against lift use must be removed. Copyright © 2013 Elsevier Ltd. All rights reserved.

Co-adaption of tRNA gene copy number and amino acid usage influences translation rates in three life domains.

PubMed

Du, Meng-Ze; Wei, Wen; Qin, Lei; Liu, Shuo; Zhang, An-Ying; Zhang, Yong; Zhou, Hong; Guo, Feng-Biao

2017-12-01

Although more and more entangled participants of translation process were realized, how they cooperate and co-determine the final translation efficiency still lacks details. Here, we reasoned that the basic translation components, tRNAs and amino acids should be consistent to maximize the efficiency and minimize the cost. We firstly revealed that 310 out of 410 investigated genomes of three domains had significant co-adaptions between the tRNA gene copy numbers and amino acid compositions, indicating that maximum efficiency constitutes ubiquitous selection pressure on protein translation. Furthermore, fast-growing and larger bacteria are found to have significantly better co-adaption and confirmed the effect of this pressure. Within organism, highly expressed proteins and those connected to acute responses have higher co-adaption intensity. Thus, the better co-adaption probably speeds up the growing of cells through accelerating the translation of special proteins. Experimentally, manipulating the tRNA gene copy number to optimize co-adaption between enhanced green fluorescent protein (EGFP) and tRNA gene set of Escherichia coli indeed lifted the translation rate (speed). Finally, as a newly confirmed translation rate regulating mechanism, the co-adaption reflecting translation rate not only deepens our understanding on translation process but also provides an easy and practicable method to improve protein translation rates and productivity. © The Author 2017. Published by Oxford University Press on behalf of Kazusa DNA Research Institute.

Maximum acceptable weight of lift reflects peak lumbosacral extension moments in a functional capacity evaluation test using free style, stoop and squat lifting.

PubMed

Kuijer, P P F M; van Oostrom, S H; Duijzer, K; van Dieën, J H

2012-01-01

It is unclear whether the maximum acceptable weight of lift (MAWL), a common psychophysical method, reflects joint kinetics when different lifting techniques are employed. In a within-participants study (n = 12), participants performed three lifting techniques--free style, stoop and squat lifting from knee to waist level--using the same dynamic functional capacity evaluation lifting test to assess MAWL and to calculate low back and knee kinetics. We assessed which knee and back kinetic parameters increased with the load mass lifted, and whether the magnitudes of the kinetic parameters were consistent across techniques when lifting MAWL. MAWL was significantly different between techniques (p = 0.03). The peak lumbosacral extension moment met both criteria: it had the highest association with the load masses lifted (r > 0.9) and was most consistent between the three techniques when lifting MAWL (ICC = 0.87). In conclusion, MAWL reflects the lumbosacral extension moment across free style, stoop and squat lifting in healthy young males, but the relation between the load mass lifted and lumbosacral extension moment is different between techniques. Tests of maximum acceptable weight of lift (MAWL) from knee to waist height are used to assess work capacity of individuals with low-back disorders. This article shows that the MAWL reflects the lumbosacral extension moment across free style, stoop and squat lifting in healthy young males, but the relation between the load mass lifted and lumbosacral extension moment is different between techniques. This suggests that standardisation of lifting technique used in tests of the MAWL would be indicated if the aim is to assess the capacity of the low back.

The Lunar IceCube Mission Design: Construction of Feasible Transfer Trajectories with a Constrained Departure

NASA Technical Reports Server (NTRS)

Folta, David C.; Bosanac, Natasha; Cox, Andrew; Howell, Kathleen C.

2016-01-01

Lunar IceCube, a 6U CubeSat, will prospect for water and other volatiles from a low-periapsis, highly inclined elliptical lunar orbit. Injected from Exploration Mission-1, a lunar gravity assisted multi-body transfer trajectory will capture into a lunar science orbit. The constrained departure asymptote and value of trans-lunar energy limit transfer trajectory types that re-encounter the Moon with the necessary energy and flight duration. Purdue University and Goddard Space Flight Center's Adaptive Trajectory Design tool and dynamical system research is applied to uncover cislunar spatial regions permitting viable transfer arcs. Numerically integrated transfer designs applying low-thrust and a design framework are described.

An iterative algorithm for L1-TV constrained regularization in image restoration

NASA Astrophysics Data System (ADS)

Chen, K.; Loli Piccolomini, E.; Zama, F.

2015-11-01

We consider the problem of restoring blurred images affected by impulsive noise. The adopted method restores the images by solving a sequence of constrained minimization problems where the data fidelity function is the ℓ1 norm of the residual and the constraint, chosen as the image Total Variation, is automatically adapted to improve the quality of the restored images. Although this approach is general, we report here the case of vectorial images where the blurring model involves contributions from the different image channels (cross channel blur). A computationally convenient extension of the Total Variation function to vectorial images is used and the results reported show that this approach is efficient for recovering nearly optimal images.

The Climate Adaptation Frontier

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

Preston, Benjamin L

2013-01-01

Climate adaptation has emerged as a mainstream risk management strategy for assisting in maintaining socio-ecological systems within the boundaries of a safe operating space. Yet, there are limits to the ability of systems to adapt. Here, we introduce the concept of an adaptation frontier , which is defined as a socio-ecological system s transitional adaptive operating space between safe and unsafe domains. A number of driving forces are responsible for determining the sustainability of systems on the frontier. These include path dependence, adaptation/development deficits, values conflicts and discounting of future loss and damage. The cumulative implications of these driving forcesmore » are highly uncertain. Nevertheless, the fact that a broad range of systems already persist at the edge of their frontiers suggests a high likelihood that some limits will eventually be exceeded. The resulting system transformation is likely to manifest as anticipatory modification of management objectives or loss and damage. These outcomes vary significantly with respect to their ethical implications. Successful navigation of the adaptation frontier will necessitate new paradigms of risk governance to elicit knowledge that encourages reflexive reevaluation of societal values that enable or constrain sustainability.« less

Viruses are a dominant driver of protein adaptation in mammals.

PubMed

Enard, David; Cai, Le; Gwennap, Carina; Petrov, Dmitri A

2016-05-17

Viruses interact with hundreds to thousands of proteins in mammals, yet adaptation against viruses has only been studied in a few proteins specialized in antiviral defense. Whether adaptation to viruses typically involves only specialized antiviral proteins or affects a broad array of virus-interacting proteins is unknown. Here, we analyze adaptation in ~1300 virus-interacting proteins manually curated from a set of 9900 proteins conserved in all sequenced mammalian genomes. We show that viruses (i) use the more evolutionarily constrained proteins within the cellular functions they interact with and that (ii) despite this high constraint, virus-interacting proteins account for a high proportion of all protein adaptation in humans and other mammals. Adaptation is elevated in virus-interacting proteins across all functional categories, including both immune and non-immune functions. We conservatively estimate that viruses have driven close to 30% of all adaptive amino acid changes in the part of the human proteome conserved within mammals. Our results suggest that viruses are one of the most dominant drivers of evolutionary change across mammalian and human proteomes.

Testing the role of phenotypic plasticity for local adaptation: growth and development in time-constrained Rana temporaria populations.

PubMed

Lind, M I; Johansson, F

2011-12-01

Phenotypic plasticity can be important for local adaptation, because it enables individuals to survive in a novel environment until genetic changes have been accumulated by genetic accommodation. By analysing the relationship between development rate and growth rate, it can be determined whether plasticity in life-history traits is caused by changed physiology or behaviour. We extended this to examine whether plasticity had been aiding local adaptation, by investigating whether the plastic response had been fixed in locally adapted populations. Tadpoles from island populations of Rana temporaria, locally adapted to different pool-drying regimes, were monitored in a common garden. Individual differences in development rate were caused by different foraging efficiency. However, developmental plasticity was physiologically mediated by trading off growth against development rate. Surprisingly, plasticity has not aided local adaptation to time-stressed environments, because local adaptation was not caused by genetic assimilation but on selection on the standing genetic variation in development time. © 2011 The Authors. Journal of Evolutionary Biology © 2011 European Society For Evolutionary Biology.

Viruses are a dominant driver of protein adaptation in mammals

PubMed Central

Enard, David; Cai, Le; Gwennap, Carina; Petrov, Dmitri A

2016-01-01

Viruses interact with hundreds to thousands of proteins in mammals, yet adaptation against viruses has only been studied in a few proteins specialized in antiviral defense. Whether adaptation to viruses typically involves only specialized antiviral proteins or affects a broad array of virus-interacting proteins is unknown. Here, we analyze adaptation in ~1300 virus-interacting proteins manually curated from a set of 9900 proteins conserved in all sequenced mammalian genomes. We show that viruses (i) use the more evolutionarily constrained proteins within the cellular functions they interact with and that (ii) despite this high constraint, virus-interacting proteins account for a high proportion of all protein adaptation in humans and other mammals. Adaptation is elevated in virus-interacting proteins across all functional categories, including both immune and non-immune functions. We conservatively estimate that viruses have driven close to 30% of all adaptive amino acid changes in the part of the human proteome conserved within mammals. Our results suggest that viruses are one of the most dominant drivers of evolutionary change across mammalian and human proteomes. DOI: http://dx.doi.org/10.7554/eLife.12469.001 PMID:27187613

If Arctic charr Salvelinus alpinus is “the most diverse vertebrate,” what is the lake charr Salvelinus namaycush?

USGS Publications Warehouse

Muir, Andrew M.; Hansen, Michael J.; Bronte, Charles R.; Krueger, Charles C.

2016-01-01

Teleost fishes are prominent vertebrate models of evolution, illustrated among old-world radiations by the Cichlidae of East African Great Lakes and new-world radiations by the circumpolar Arctic charr Salvelinus alpinus. Herein, we describe variation in lake charr S. namaycush morphology, life history, physiology, and ecology, as another example of radiation. The lake charr is restricted to northern North America, where it originated from glacial refugia and diversified in large lakes. Shallow and deepwater morphs arose in multiple lakes, with a large-bodied shallow-water ‘lean’ morph in shallow inshore depths, a small-bodied mid-water ‘humper’ morph on offshore shoals or banks, and a large-bodied deep-water ‘siscowet’ morph at depths > 100 m. Eye position, gape size, and gillraker length and spacing adapted for feeding on different-sized prey, with piscivorous morphs (leans and siscowets) reaching larger asymptotic size than invertivorous morphs (humpers). Lean morphs are light in color, whereas deepwater morphs are drab and dark, although the pattern is reversed in dark tannic lakes. Morphs shift from benthic to pelagic feeding at a length of 400–490-mm. Phenotypic differences in locomotion, buoyancy, and lipid metabolism evolved into different mechanisms for buoyancy regulation, with lean morphs relying on hydrodynamic lift and siscowet morphs relying on hydrostatic lift. We suggest that the Salvelinus genus, rather than the species S. alpinus, is a diverse genus that should be the subject of comparative studies of processes causing divergence and adaptation among member species that may lead to a more complete evolutionary conceptual model.

InSight Atlas V ISA-ASA Lift and Mate

NASA Image and Video Library

2018-03-05

At Space Launch Complex 3 at Vandenberg Air Force Base in California, a technician assists as the aft stub adapter (ASA) and interstage adapter (ISA) for a United Launch Alliance (ULA) Atlas V is lifted by crane for mating atop a Centaur upper stage. The launch vehicle will send NASA's Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, or InSight, spacecraft to land on Mars. InSight is the first mission to explore the Red Planet's deep interior. InSight is scheduled for liftoff May 5, 2018. InSight will be the first mission to look deep beneath the Martian surface. It will study the planet's interior by measuring its heat output and listen for marsquakes. InSight will use the seismic waves generated by marsquakes to develop a map of the planet’s deep interior. The resulting insight into Mars’ formation will provide a better understanding of how other rocky planets, including Earth, were created. NASA’s Jet Propulsion Laboratory in Pasadena, California, manages the InSight mission for the agency’s Science Mission Directorate. InSight is part of NASA's Discovery Program, managed by its Marshall Space Flight Center in Huntsville, Alabama. The spacecraft, including cruise stage and lander, was built and tested by Lockheed Martin Space in Denver. Several European partners, including France's space agency, the Centre National d'Étude Spatiales, and the German Aerospace Center, are supporting the mission. United Launch Alliance of Centennial, Colorado, is providing the Atlas V launch service. NASA’s Launch Services Program, based at its Kennedy Space Center in Florida, is responsible for launch management.

KENNEDY SPACE CENTER, FLA. - An overhead crane in the Space Station Processing Facility is attached to the U.S. Node 2 to lift it out of its shipping container. The node will be moved to a workstand. The second of three connecting modules on the International Space Station, the Italian-built Node 2 attaches to the end of the U.S. Lab and provides attach locations for the Japanese laboratory, European laboratory, the Centrifuge Accommodation Module and, later, Multipurpose Logistics Modules. It will provide the primary docking location for the Shuttle when a pressurized mating adapter is attached to Node 2. Installation of the module will complete the U.S. Core of the ISS. Node 2 is the designated payload for mission STS-120. No orbiter or launch date has been determined yet.

NASA Image and Video Library

2003-06-03

KENNEDY SPACE CENTER, FLA. - An overhead crane in the Space Station Processing Facility is attached to the U.S. Node 2 to lift it out of its shipping container. The node will be moved to a workstand. The second of three connecting modules on the International Space Station, the Italian-built Node 2 attaches to the end of the U.S. Lab and provides attach locations for the Japanese laboratory, European laboratory, the Centrifuge Accommodation Module and, later, Multipurpose Logistics Modules. It will provide the primary docking location for the Shuttle when a pressurized mating adapter is attached to Node 2. Installation of the module will complete the U.S. Core of the ISS. Node 2 is the designated payload for mission STS-120. No orbiter or launch date has been determined yet.

The Relationship between Diaspore Characteristics with Phylogeny, Life History Traits, and Their Ecological Adaptation of 150 Species from the Cold Desert of Northwest China

PubMed Central

Liu, Hui-Liang; Zhang, Dao-Yuan; Duan, Shi-Min; Wang, Xi-Yong; Song, Ming-Fang

2014-01-01

Diaspore characteristics of 22 families, including 102 genera and 150 species (55 represented by seeds and 95 by fruits) from the Gurbantunggut Desert were analyzed for diaspore biological characteristics (mass, shape, color, and appendage type). The diaspore mass and shape were significantly different in phylogeny group (APG) and dispersal syndromes; vegetative periods significantly affected diaspore mass, but not diaspore shape; and ecotypes did not significantly affect diaspore mass and shape, but xerophyte species had larger diaspore mass than mesophyte species. Unique stepwise ANOVA results showed that variance in diaspore mass and shape among these 150 species was largely dependent upon phylogeny and dispersal syndromes. Therefore, it was suggested that phylogeny may constrain diaspore mass, and as dispersal syndromes may be related to phylogeny, they also constrained diaspore mass and shape. Diaspores of 85 species (56.67%) had appendages, including 26 with wings/bracts, 18 with pappus/hair, 14 with hooks/spines, 10 with awns, and 17 with other types of appendages. Different traits (mass, shape, color, appendage, and dispersal syndromes) of diaspore decided plants forming different adapted strategies in the desert. In summary, the diaspore characteristics were closely related with phylogeny, vegetative periods, dispersal syndromes, and ecotype, and these characteristics allowed the plants to adapt to extreme desert environments. PMID:24605054

33 CFR 118.85 - Lights on vertical lift bridges.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Lights on vertical lift bridges... BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.85 Lights on vertical lift bridges. (a) Lift span lights. The vertical lift span of every vertical lift bridge shall be lighted so that the center of the...

33 CFR 118.85 - Lights on vertical lift bridges.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lights on vertical lift bridges... BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.85 Lights on vertical lift bridges. (a) Lift span lights. The vertical lift span of every vertical lift bridge shall be lighted so that the center of the...

Load-embedded inertial measurement unit reveals lifting performance.

PubMed

Tammana, Aditya; McKay, Cody; Cain, Stephen M; Davidson, Steven P; Vitali, Rachel V; Ojeda, Lauro; Stirling, Leia; Perkins, Noel C

2018-07-01

Manual lifting of loads arises in many occupations as well as in activities of daily living. Prior studies explore lifting biomechanics and conditions implicated in lifting-induced injuries through laboratory-based experimental methods. This study introduces a new measurement method using load-embedded inertial measurement units (IMUs) to evaluate lifting tasks in varied environments outside of the laboratory. An example vertical load lifting task is considered that is included in an outdoor obstacle course. The IMU data, in the form of the load acceleration and angular velocity, is used to estimate load vertical velocity and three lifting performance metrics: the lifting time (speed), power, and motion smoothness. Large qualitative differences in these parameters distinguish exemplar high and low performance trials. These differences are further supported by subsequent statistical analyses of twenty three trials (including a total of 115 total lift/lower cycles) from fourteen healthy participants. Results reveal that lifting time is strongly correlated with lifting power (as expected) but also correlated with motion smoothness. Thus, participants who lift rapidly do so with significantly greater power using motions that minimize motion jerk. Copyright © 2018 Elsevier Ltd. All rights reserved.

Study on process design of partially-balanced, hydraulically lifting vertical ship lift

NASA Astrophysics Data System (ADS)

Xin, Shen; Xiaofeng, Xu; Lu, Zhang; Bing, Zhu; Fei, Li

2017-11-01

The hub ship lift in Panjin is the first navigation structure in China for the link between the inland and open seas, which adopts a novel partially-balanced, hydraulically lifting ship lift; it can meet such requirements as fast and sharp water level change in open sea, large draft of a yacht, and launching of a ship reception chamber; its balancing weight system can effectively reduce the load of the primary lifting cylinder, and optimize the force distribution of the ship reception chamber. The paper provides an introduction to main equipment, basic principles, main features and system composition of a ship lift. The unique power system and balancing system of the completed ship lift has offered some experience for the construction of the tourism-type ship lifts with a lower lifting height.

Instant preheating in quintessential inflation with α -attractors

NASA Astrophysics Data System (ADS)

Dimopoulos, Konstantinos; Wood, Leonora Donaldson; Owen, Charlotte

2018-03-01

We investigate a compelling model of quintessential inflation in the context of α -attractors, which naturally result in a scalar potential featuring two flat regions; the inflationary plateau and the quintessential tail. The "asymptotic freedom" of α -attractors, near the kinetic poles, suppresses radiative corrections and interactions, which would otherwise threaten to lift the flatness of the quintessential tail and cause a 5th-force problem respectively. Since this is a nonoscillatory inflation model, we reheat the Universe through instant preheating. The parameter space is constrained by both inflation and dark energy requirements. We find an excellent correlation between the inflationary observables and model predictions, in agreement with the α -attractors setup. We also obtain successful quintessence for natural values of the parameters. Our model predicts potentially sizeable tensor perturbations (at the level of 1%) and a slightly varying equation of state for dark energy, to be probed in the near future.

Conference on Low Reynolds Number Airfoil Aerodynamics, Notre Dame, IN, June 16-18, 1985, Proceedings

NASA Technical Reports Server (NTRS)

Mueller, T. J. (Editor)

1985-01-01

Topics of interest in the design, flow modeling and visualization, and turbulence and flow separation effects for low Reynolds number (Re) airfoils are discussed. Design methods are presented for Re from 50,000-500,000, including a viscous-inviscid coupling method and by using a constrained pitching moment. The effects of pressure gradients, unsteady viscous aerodynamics and separation bubbles are investigated, with particular note made of factors which most influence the size and location of separation bubbles and control their effects. Attention is also given to experimentation with low Re airfoils and to numerical models of symmetry breaking and lift hysteresis from separation. Both steady and unsteady flow experiments are reviewed, with the trials having been held in wind tunnels and the free atmosphere. The topics discussed are of interest to designers of RPVs, high altitude aircraft, sailplanes, ultralights and wind turbines.

Options for Robust Airfoil Optimization under Uncertainty

NASA Technical Reports Server (NTRS)

Padula, Sharon L.; Li, Wu

2002-01-01

A robust optimization method is developed to overcome point-optimization at the sampled design points. This method combines the best features from several preliminary methods proposed by the authors and their colleagues. The robust airfoil shape optimization is a direct method for drag reduction over a given range of operating conditions and has three advantages: (1) it prevents severe degradation in the off-design performance by using a smart descent direction in each optimization iteration, (2) it uses a large number of spline control points as design variables yet the resulting airfoil shape does not need to be smoothed, and (3) it allows the user to make a tradeoff between the level of optimization and the amount of computing time consumed. For illustration purposes, the robust optimization method is used to solve a lift-constrained drag minimization problem for a two-dimensional (2-D) airfoil in Euler flow with 20 geometric design variables.

Computational wing optimization and comparisons with experiment for a semi-span wing model

NASA Technical Reports Server (NTRS)

Waggoner, E. G.; Haney, H. P.; Ballhaus, W. F.

1978-01-01

A computational wing optimization procedure was developed and verified by an experimental investigation of a semi-span variable camber wing model in the NASA Ames Research Center 14 foot transonic wind tunnel. The Bailey-Ballhaus transonic potential flow analysis and Woodward-Carmichael linear theory codes were linked to Vanderplaats constrained minimization routine to optimize model configurations at several subsonic and transonic design points. The 35 deg swept wing is characterized by multi-segmented leading and trailing edge flaps whose hinge lines are swept relative to the leading and trailing edges of the wing. By varying deflection angles of the flap segments, camber and twist distribution can be optimized for different design conditions. Results indicate that numerical optimization can be both an effective and efficient design tool. The optimized configurations had as good or better lift to drag ratios at the design points as the best designs previously tested during an extensive parametric study.

An ergonomics approach model to prevention of occupational musculoskeletal injuries.

PubMed

Koltan, Altan

2009-01-01

The objective of this study was to prevent occupational musculoskeletal injuries. Our workers stacked boxes of ceramics weighing 10-27 kg, making low back pain common in our enterprise. In all the stacking stations, recommended weight limits (RWL) were separately calculated using the revised National Institute for Occupational Health lifting equation. Since the boxes weighed significantly more than the RWL, we developed a new ergonomic design that completely changed the stacking process. The load put on the workers' waist vertebrae in the new and the old stacking methods was compared to evaluate the success of the new ergonomic design, using Newton's third law of motion. Thanks to the new ergonomic design, the load on the workers' vertebrae decreased by 80%. Due to its simple technology and its very low cost compared to robots, the new ergonomic design can be commonly used in enterprises with repeated and constraining stacking.

Self-assembled fibre optoelectronics with discrete translational symmetry

PubMed Central

Rein, Michael; Levy, Etgar; Gumennik, Alexander; Abouraddy, Ayman F.; Joannopoulos, John; Fink, Yoel

2016-01-01

Fibres with electronic and photonic properties are essential building blocks for functional fabrics with system level attributes. The scalability of thermal fibre drawing approach offers access to large device quantities, while constraining the devices to be translational symmetric. Lifting this symmetry to create discrete devices in fibres will increase their utility. Here, we draw, from a macroscopic preform, fibres that have three parallel internal non-contacting continuous domains; a semiconducting glass between two conductors. We then heat the fibre and generate a capillary fluid instability, resulting in the selective transformation of the cylindrical semiconducting domain into discrete spheres while keeping the conductive domains unchanged. The cylindrical-to-spherical expansion bridges the continuous conducting domains to create ∼104 self-assembled, electrically contacted and entirely packaged discrete spherical devices per metre of fibre. The photodetection and Mie resonance dependent response are measured by illuminating the fibre while connecting its ends to an electrical readout. PMID:27698454

An Approach to the Constrained Design of Natural Laminar Flow Airfoils

NASA Technical Reports Server (NTRS)

Green, Bradford E.

1997-01-01

A design method has been developed by which an airfoil with a substantial amount of natural laminar flow can be designed, while maintaining other aerodynamic and geometric constraints. After obtaining the initial airfoil's pressure distribution at the design lift coefficient using an Euler solver coupled with an integral turbulent boundary layer method, the calculations from a laminar boundary layer solver are used by a stability analysis code to obtain estimates of the transition location (using N-Factors) for the starting airfoil. A new design method then calculates a target pressure distribution that will increase the laminar flow toward the desired amount. An airfoil design method is then iteratively used to design an airfoil that possesses that target pressure distribution. The new airfoil's boundary layer stability characteristics are determined, and this iterative process continues until an airfoil is designed that meets the laminar flow requirement and as many of the other constraints as possible.

An approach to the constrained design of natural laminar flow airfoils

NASA Technical Reports Server (NTRS)

Green, Bradford Earl

1995-01-01

A design method has been developed by which an airfoil with a substantial amount of natural laminar flow can be designed, while maintaining other aerodynamic and geometric constraints. After obtaining the initial airfoil's pressure distribution at the design lift coefficient using an Euler solver coupled with an integml turbulent boundary layer method, the calculations from a laminar boundary layer solver are used by a stability analysis code to obtain estimates of the transition location (using N-Factors) for the starting airfoil. A new design method then calculates a target pressure distribution that will increase the larninar flow toward the desired amounl An airfoil design method is then iteratively used to design an airfoil that possesses that target pressure distribution. The new airfoil's boundary layer stability characteristics are determined, and this iterative process continues until an airfoil is designed that meets the laminar flow requirement and as many of the other constraints as possible.

Self-assembled fibre optoelectronics with discrete translational symmetry.

PubMed

Rein, Michael; Levy, Etgar; Gumennik, Alexander; Abouraddy, Ayman F; Joannopoulos, John; Fink, Yoel

2016-10-04

Fibres with electronic and photonic properties are essential building blocks for functional fabrics with system level attributes. The scalability of thermal fibre drawing approach offers access to large device quantities, while constraining the devices to be translational symmetric. Lifting this symmetry to create discrete devices in fibres will increase their utility. Here, we draw, from a macroscopic preform, fibres that have three parallel internal non-contacting continuous domains; a semiconducting glass between two conductors. We then heat the fibre and generate a capillary fluid instability, resulting in the selective transformation of the cylindrical semiconducting domain into discrete spheres while keeping the conductive domains unchanged. The cylindrical-to-spherical expansion bridges the continuous conducting domains to create ∼10 4 self-assembled, electrically contacted and entirely packaged discrete spherical devices per metre of fibre. The photodetection and Mie resonance dependent response are measured by illuminating the fibre while connecting its ends to an electrical readout.

Burst Oscillation Probes of Neutron Stars and Nuclear Burning with LOFT

NASA Technical Reports Server (NTRS)

Strohmayer, Tod

2012-01-01

X-ray brightness oscillations during thermonuclear X-ray bursts--burst oscillations--have provided a new probe of neutron star spins as well as of the dependent nuclear burning processes. The frequency drift and amplitude evolution of the oscillations observed during bursts can in principle place constraints on the physics of thermonuclear flame spreading and the dynamics of the burning atmosphere. I use simulations appropriate to LOFT to explore the precision with which the time dependence of the oscillation frequency can be inferred. This can test, for example, different models for the frequency drift, such as up-lift versus geostrophic drift. I also explore the precision with which asymptotic frequencies can be constrained in order to estimate the capability for LOFT to detect the Doppler shifts induced by orbital motion of the neutron star from a sample of bursts at different orbital phases.

A Method for the Constrained Design of Natural Laminar Flow Airfoils

NASA Technical Reports Server (NTRS)

Green, Bradford E.; Whitesides, John L.; Campbell, Richard L.; Mineck, Raymond E.

1996-01-01

A fully automated iterative design method has been developed by which an airfoil with a substantial amount of natural laminar flow can be designed, while maintaining other aerodynamic and geometric constraints. Drag reductions have been realized using the design method over a range of Mach numbers, Reynolds numbers and airfoil thicknesses. The thrusts of the method are its ability to calculate a target N-Factor distribution that forces the flow to undergo transition at the desired location; the target-pressure-N-Factor relationship that is used to reduce the N-Factors in order to prolong transition; and its ability to design airfoils to meet lift, pitching moment, thickness and leading-edge radius constraints while also being able to meet the natural laminar flow constraint. The method uses several existing CFD codes and can design a new airfoil in only a few days using a Silicon Graphics IRIS workstation.

The Articulation of Sauropod Necks: Methodology and Mythology

PubMed Central

Stevens, Kent A.

2013-01-01

Sauropods are often imagined to have held their heads high atop necks that ascended in a sweeping curve that was formed either intrinsically because of the shape of their vertebrae, or behaviorally by lifting the head, or both. Their necks are also popularly depicted in life with poses suggesting avian flexibility. The grounds for such interpretations are examined in terms of vertebral osteology, inferences about missing soft tissues, intervertebral flexibility, and behavior. Osteologically, the pronounced opisthocoely and conformal central and zygapophyseal articular surfaces strongly constrain the reconstruction of the cervical vertebral column. The sauropod cervico-dorsal vertebral column is essentially straight, in contrast to the curvature exhibited in those extant vertebrates that naturally hold their heads above rising necks. Regarding flexibility, extant vertebrates with homologous articular geometries preserve a degree of zygapophyseal overlap at the limits of deflection, a constraint that is further restricted by soft tissues. Sauropod necks, if similarly constrained, were capable of sweeping out large feeding surfaces, yet much less capable of retracting the head to explore the enclosed volume in an avian manner. Behaviorally, modern vertebrates generally assume characteristic neck postures which are close to the intrinsic curvature of the undeflected neck. With the exception of some vertebrates that can retract their heads to balance above their shoulders at rest (e.g., felids, lagomorphs, and some ratites), the undeflected neck generally predicts the default head height at rest and during locomotion. PMID:24205266

The articulation of sauropod necks: methodology and mythology.

PubMed

Stevens, Kent A

2013-01-01

Sauropods are often imagined to have held their heads high atop necks that ascended in a sweeping curve that was formed either intrinsically because of the shape of their vertebrae, or behaviorally by lifting the head, or both. Their necks are also popularly depicted in life with poses suggesting avian flexibility. The grounds for such interpretations are examined in terms of vertebral osteology, inferences about missing soft tissues, intervertebral flexibility, and behavior. Osteologically, the pronounced opisthocoely and conformal central and zygapophyseal articular surfaces strongly constrain the reconstruction of the cervical vertebral column. The sauropod cervico-dorsal vertebral column is essentially straight, in contrast to the curvature exhibited in those extant vertebrates that naturally hold their heads above rising necks. Regarding flexibility, extant vertebrates with homologous articular geometries preserve a degree of zygapophyseal overlap at the limits of deflection, a constraint that is further restricted by soft tissues. Sauropod necks, if similarly constrained, were capable of sweeping out large feeding surfaces, yet much less capable of retracting the head to explore the enclosed volume in an avian manner. Behaviorally, modern vertebrates generally assume characteristic neck postures which are close to the intrinsic curvature of the undeflected neck. With the exception of some vertebrates that can retract their heads to balance above their shoulders at rest (e.g., felids, lagomorphs, and some ratites), the undeflected neck generally predicts the default head height at rest and during locomotion.

A Real-Time Lift Detection Strategy for a Hip Exoskeleton

PubMed Central

Chen, Baojun; Grazi, Lorenzo; Lanotte, Francesco; Vitiello, Nicola; Crea, Simona

2018-01-01

Repetitive lifting of heavy loads increases the risk of back pain and even lumbar vertebral injuries to workers. Active exoskeletons can help workers lift loads by providing power assistance, and therefore reduce the moment and force applied on L5/S1 joint of human body when performing lifting tasks. However, most existing active exoskeletons for lifting assistance are unable to automatically detect user's lift movement, which limits the wide application of active exoskeletons in factories. In this paper, we propose a simple but effective lift detection strategy for exoskeleton control. This strategy uses only exoskeleton integrated sensors, without any extra sensors to capture human motion intentions. This makes the lift detection system more practical for applications in manufacturing environments. Seven healthy subjects participated in this research. Three different sessions were carried out, two for training and one for testing the algorithm. In the two training sessions, subjects were asked to wear a hip exoskeleton, controlled in transparent mode, and perform repetitive lifting and a locomotion circuit; lifting was executed with different techniques. The collected data were used to train the lift detection model. In the testing session, the exoskeleton was controlled in order to deliver torque to assist the lifting action, based on the lift detection made by the trained algorithm. The across-subject average accuracy of lift detection during online test was 97.97 ± 1.39% with subject-dependent model. Offline, the algorithm was trained with data acquired from all subjects to verify its performance for subject-independent detection, and an accuracy of 97.48 ± 1.53% was achieved. In addition, timeliness of the algorithm was quantitatively evaluated and the time delay was <160 ms across different lifting speeds. Surface electromyography was also measured to assess the efficacy of the exoskeleton in assisting subjects in performing load lifting tasks. These results validate the promise of applying the proposed lift detection strategy for exoskeleton control aiming at lift assistance. PMID:29706881

A Real-Time Lift Detection Strategy for a Hip Exoskeleton.

PubMed

Chen, Baojun; Grazi, Lorenzo; Lanotte, Francesco; Vitiello, Nicola; Crea, Simona

2018-01-01

Repetitive lifting of heavy loads increases the risk of back pain and even lumbar vertebral injuries to workers. Active exoskeletons can help workers lift loads by providing power assistance, and therefore reduce the moment and force applied on L5/S1 joint of human body when performing lifting tasks. However, most existing active exoskeletons for lifting assistance are unable to automatically detect user's lift movement, which limits the wide application of active exoskeletons in factories. In this paper, we propose a simple but effective lift detection strategy for exoskeleton control. This strategy uses only exoskeleton integrated sensors, without any extra sensors to capture human motion intentions. This makes the lift detection system more practical for applications in manufacturing environments. Seven healthy subjects participated in this research. Three different sessions were carried out, two for training and one for testing the algorithm. In the two training sessions, subjects were asked to wear a hip exoskeleton, controlled in transparent mode, and perform repetitive lifting and a locomotion circuit; lifting was executed with different techniques. The collected data were used to train the lift detection model. In the testing session, the exoskeleton was controlled in order to deliver torque to assist the lifting action, based on the lift detection made by the trained algorithm. The across-subject average accuracy of lift detection during online test was 97.97 ± 1.39% with subject-dependent model. Offline, the algorithm was trained with data acquired from all subjects to verify its performance for subject-independent detection, and an accuracy of 97.48 ± 1.53% was achieved. In addition, timeliness of the algorithm was quantitatively evaluated and the time delay was <160 ms across different lifting speeds. Surface electromyography was also measured to assess the efficacy of the exoskeleton in assisting subjects in performing load lifting tasks. These results validate the promise of applying the proposed lift detection strategy for exoskeleton control aiming at lift assistance.

System and method for controlling hydraulic pressure in electro-hydraulic valve actuation systems

DOEpatents

Brennan, Daniel G; Marriott, Craig D; Cowgill, Joel; Wiles, Matthew A; Patton, Kenneth James

2014-09-23

A control system for an engine includes a first lift control module and a second lift control module. The first lift control module increases lift of M valves of the engine to a predetermined valve lift during a period before disabling or re-enabling N valves of the engine. The second lift control module decreases the lift of the M valves to a desired valve lift during a period after enabling or re-enabling the N valves of the engine, wherein N and M are integers greater than or equal to one.

Aerodynamic characteristics of flying fish in gliding flight.

PubMed

Park, Hyungmin; Choi, Haecheon

2010-10-01

The flying fish (family Exocoetidae) is an exceptional marine flying vertebrate, utilizing the advantages of moving in two different media, i.e. swimming in water and flying in air. Despite some physical limitations by moving in both water and air, the flying fish has evolved to have good aerodynamic designs (such as the hypertrophied fins and cylindrical body with a ventrally flattened surface) for proficient gliding flight. Hence, the morphological and behavioral adaptations of flying fish to aerial locomotion have attracted great interest from various fields including biology and aerodynamics. Several aspects of the flight of flying fish have been determined or conjectured from previous field observations and measurements of morphometric parameters. However, the detailed measurement of wing performance associated with its morphometry for identifying the characteristics of flight in flying fish has not been performed yet. Therefore, in the present study, we directly measure the aerodynamic forces and moment on darkedged-wing flying fish (Cypselurus hiraii) models and correlated them with morphological characteristics of wing (fin). The model configurations considered are: (1) both the pectoral and pelvic fins spread out, (2) only the pectoral fins spread with the pelvic fins folded, and (3) both fins folded. The role of the pelvic fins was found to increase the lift force and lift-to-drag ratio, which is confirmed by the jet-like flow structure existing between the pectoral and pelvic fins. With both the pectoral and pelvic fins spread, the longitudinal static stability is also more enhanced than that with the pelvic fins folded. For cases 1 and 2, the lift-to-drag ratio was maximum at attack angles of around 0 deg, where the attack angle is the angle between the longitudinal body axis and the flying direction. The lift coefficient is largest at attack angles around 30∼35 deg, at which the flying fish is observed to emerge from the sea surface. From glide polar, we find that the gliding performance of flying fish is comparable to those of bird wings such as the hawk, petrel and wood duck. However, the induced drag by strong wing-tip vortices is one of the dominant drag components. Finally, we examine ground effect on the aerodynamic forces of the gliding flying fish and find that the flying fish achieves the reduction of drag and increase of lift-to-drag ratio by flying close to the sea surface.

Cascade Classification with Adaptive Feature Extraction for Arrhythmia Detection.

PubMed

Park, Juyoung; Kang, Mingon; Gao, Jean; Kim, Younghoon; Kang, Kyungtae

2017-01-01

Detecting arrhythmia from ECG data is now feasible on mobile devices, but in this environment it is necessary to trade computational efficiency against accuracy. We propose an adaptive strategy for feature extraction that only considers normalized beat morphology features when running in a resource-constrained environment; but in a high-performance environment it takes account of a wider range of ECG features. This process is augmented by a cascaded random forest classifier. Experiments on data from the MIT-BIH Arrhythmia Database showed classification accuracies from 96.59% to 98.51%, which are comparable to state-of-the art methods.

Spatial attention can modulate unconscious orientation processing.

PubMed

Bahrami, Bahador; Carmel, David; Walsh, Vincent; Rees, Geraint; Lavie, Nilli

2008-01-01

It has recently been suggested that visual spatial attention can only affect consciously perceived events. We measured the effects of sustained spatial attention on orientation-selective adaptation to gratings, rendered invisible by prolonged interocular suppression. Spatial attention augmented the orientation-selective adaptation to invisible adaptor orientation. The effect of attention was clearest for test stimuli at peri-threshold, intermediate contrast levels, suggesting that previous negative results were due to assessing orientation discrimination at maximum contrast. On the basis of these findings we propose a constrained hypothesis for the difference between neuronal mechanisms of spatial attention in the presence versus absence of awareness.

A hypersonic lift mechanism with decoupled lift and drag surfaces

NASA Astrophysics Data System (ADS)

Xu, YiZhe; Xu, ZhiQi; Li, ShaoGuang; Li, Juan; Bai, ChenYuan; Wu, ZiNiu

2013-05-01

In the present study, we propose a novel lift mechanism for which the lifting surface produces only lift. This is achieved by mounting a two-dimensional shock-shock interaction generator below the lifting surface. The shock-shock interaction theory in conjunction with a three dimensional correction and checked with computational fluid dynamics (CFD) is used to analyze the lift and drag forces as function of the geometrical parameters and inflow Mach number. Through this study, though limited to only inviscid flow, we conclude that it is possible to obtain a high lift to drag ratio by suitably arranging the shock interaction generator.

[Origin of lifting and lowering theory and its herb pair study].

PubMed

Guo, Zhao-Juan; Yuan, Yi-Ping; Kong, Li-Ting; Jia, Xiao-Yu; Wang, Ning-Ning; Dai, Ying; Zhai, Hua-Qiang

2017-08-01

Lifting and lowering theory is one of the important basis for guiding clinical medication. Through the study of ancient books and literature, we learned that lifting and lowering theory was originated in Huangdi Neijing, practiced more in the Shanghan Zabing Lun, established in Yixue Qiyuan, and developed in Compendium of Materia Medica and now. However, lifting and lowering theory is now mostly stagnated in the theoretical stage, with few experimental research. In the clinical study, the guiding role of lifting and lowering theory to prescriptions?mainly includes opposite?role?of lift and lower medicine property, mutual promotion of lift and lower medicine property, main role of lift medicine property and main role of lower medicine property. Under the guidance of lifting and lowering theory, the herb pair compatibility include herb combination of lift medicine property, herb combination of lift and lower medicine property and herb combination of lower medicine property. Modern biological technology was used in this study to carry out experimental research on the lifting and lowering theory, revealing the scientific connotation of it, which will help to promote clinical rational drug use. Copyright© by the Chinese Pharmaceutical Association.

Measurement and characterization of lift forces on drops and bubbles in microchannels

NASA Astrophysics Data System (ADS)

Stan, Claudiu; Guglielmini, Laura; Ellerbee, Audrey; Caviezel, Daniel; Whitesides, George; Stone, Howard

2013-11-01

The transverse motion of drops and bubbles within liquids flowing in pipes and channels is determined by the combination of several types of hydrodynamic lift forces with external forces. In microfluidic channels, lift forces have been used to position and sort particles with high efficiency and high accuracy. We measured lift forces on drops and bubbles and discriminated between different lift mechanisms under conditions characterized by low particle capillary numbers (0.0003 < CaP < 0.3) and low particle Reynolds numbers (0.0001 < ReP < 0.1). The measured lift forces were often much larger (up to a factor of 1000) than the predictions of analytical models of inertial and deformation-induced lift, indicating that another lift mechanism was the largest contributor to the total lift force. The systems we investigated exhibited either (i) a deformation-induced lift force enhanced by confinement effects, or (ii) a lift force for which to our best knowledge is based on physicochemical effects at the interfaces of drops and bubbles. We will present new experimental data that supports a dynamic interfacial mechanism for the second type of lift force, and discuss possible avenues for creating an analytical model for it.

Coordinated trajectory planning of dual-arm space robot using constrained particle swarm optimization

NASA Astrophysics Data System (ADS)

Wang, Mingming; Luo, Jianjun; Yuan, Jianping; Walter, Ulrich

2018-05-01

Application of the multi-arm space robot will be more effective than single arm especially when the target is tumbling. This paper investigates the application of particle swarm optimization (PSO) strategy to coordinated trajectory planning of the dual-arm space robot in free-floating mode. In order to overcome the dynamics singularities issue, the direct kinematics equations in conjunction with constrained PSO are employed for coordinated trajectory planning of dual-arm space robot. The joint trajectories are parametrized with Bézier curve to simplify the calculation. Constrained PSO scheme with adaptive inertia weight is implemented to find the optimal solution of joint trajectories while specific objectives and imposed constraints are satisfied. The proposed method is not sensitive to the singularity issue due to the application of forward kinematic equations. Simulation results are presented for coordinated trajectory planning of two kinematically redundant manipulators mounted on a free-floating spacecraft and demonstrate the effectiveness of the proposed method.

Constraints to hydraulic acclimation under reduced light in two contrasting Phaseolus vulgaris cultivars.

PubMed

Matzner, Steven L; Rettedal, David D; Harmon, Derek A; Beukelman, MacKenzie R

2014-08-01

Two cultivars of Phaseolus vulgaris L. were grown under three light levels to determine if hydraulic acclimation to light occurs in herbaceous annuals and whether intraspecific trade-offs constrain hydraulic traits. Acclimation occurred in response to reduced light and included decreased stomatal density (SD) and increased specific leaf area (SLA). Reduced light resulted in lower wood density (WD); decreased cavitation resistance, measured as the xylem pressure causing a 50 % reduction in stem conductivity (P50); and increased hydraulic capacity, measured as average leaf mass specific transpiration (E(LM)). Significant or marginally significant trade-offs between P50 and WD, WD and E(LM), and E(LM) and P50 reflected variation due to both genotype and environmental effects. A trade-off between WD and P50 within one cultivar indicated that morphological adjustment was constrained. Coordinated changes in WD, P50, and E(LM) within each cultivar in response to light were consistent with trade-offs constraining plasticity. A water-use efficiency (WUE, measured as δ(13)C) versus hydraulic capacity (E(LM)) trade-off was observed within each cultivar, further indicating that hydraulic trade-offs can constrain acclimation. Larger plants had lower hydraulic capacity (E(LM)) but greater cavitation resistance, WD, and WUE. Distinct hydraulic strategies were observed with the cultivar adapted to irrigated conditions having higher stomatal conductance and stem flow rates. The cultivar adapted to rain-fed conditions had higher leaf area and greater cavitation resistance. Hydraulic trade-offs were observed within the herbaceous P. vulgaris resulting from both genotype and environmental effects. Trade-offs within a cultivar reflected constraints to hydraulic acclimation in response to changing light. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Changing paradigms: Manufacturing vs. fabricating a high volume Hold Down and Release Mechanism

NASA Technical Reports Server (NTRS)

Maus, Daryl; Monick, Doug

1995-01-01

A detailed description of the Hold Down and Release Mechanisms designed for a 70+ constellation of spacecraft is presented. The design is reviewed to understand the practical implications of severely constraining cost. Strategies for adapting the traditional aerospace design paradigm to a more commercial, cost driven paradigm are discussed and practical examples are cited.

Explaining spatial variability in stream habitats using both natural and management-influenced landscape predictors

Treesearch

K.J. Anlauf; D.W. Jensen; K.M. Burnett; E.A. Steel; K. Christiansen; J.C. Firman; B.E. Feist; D.P. Larsen

2011-01-01

1. The distribution and composition of in-stream habitats are reflections of landscape scale geomorphic and climatic controls. Correspondingly, Pacific salmon (Oncorhynchus spp.) are largely adapted to and constrained by the quality and complexity of those in-stream habitat conditions. The degree to which lands have been fragmented and managed can...

Delivering and Assessing Learning Material through Gquest: A Case Study on Patient Education

ERIC Educational Resources Information Center

Lanzola, Giordano; Ginardi, Germana; Russo, Paola; Quaglini, Silvana

2014-01-01

Gquest is a mobile platform for administering interviewing and learning material. It relies on a model that supports adaptivity in the dialog with its users and enforces consistency rules to constrain their input. Gquest downloads its modules over the air making them available to the users, then a synchronization engine collects any input provided…

When Procedures Discourage Insight: Epistemological Consequences of Prompting Novice Physics Students to Construct Force Diagrams

ERIC Educational Resources Information Center

Kuo, Eric; Hallinen, Nicole R.; Conlin, Luke D.

2017-01-01

One aim of school science instruction is to help students become adaptive problem solvers. Though successful at structuring novice problem solving, step-by-step problem-solving frameworks may also constrain students' thinking. This study utilises a paradigm established by Heckler [(2010). Some consequences of prompting novice physics students to…

Exploring Two Secondary Social Studies Teachers' Pedagogical Decision Making in Constrained and Flexible Curricular Contexts

ERIC Educational Resources Information Center

Meuwissen, Kevin William

2012-01-01

With current trends in K-12 education toward curriculum centralization and high-stakes test-based accountability, teachers are in a position of increasingly adapting their practices to demands that originate beyond the classroom. A synthesis of literature on the relationship between these external influences and secondary social studies teaching…

Adapting to the surface: A comparison of handwriting measures when writing on a tablet computer and on paper.

PubMed

Gerth, Sabrina; Dolk, Thomas; Klassert, Annegret; Fliesser, Michael; Fischer, Martin H; Nottbusch, Guido; Festman, Julia

2016-08-01

Our study addresses the following research questions: Are there differences between handwriting movements on paper and on a tablet computer? Can experienced writers, such as most adults, adapt their graphomotor execution during writing to a rather unfamiliar surface for instance a tablet computer? We examined the handwriting performance of adults in three tasks with different complexity: (a) graphomotor abilities, (b) visuomotor abilities and (c) handwriting. Each participant performed each task twice, once on paper and once on a tablet computer with a pen. We tested 25 participants by measuring their writing duration, in air time, number of pen lifts, writing velocity and number of inversions in velocity. The data were analyzed using linear mixed-effects modeling with repeated measures. Our results reveal differences between writing on paper and on a tablet computer which were partly task-dependent. Our findings also show that participants were able to adapt their graphomotor execution to the smoother surface of the tablet computer during the tasks. Copyright © 2016 Elsevier B.V. All rights reserved.

Body armour and lateral-plate reduction in freshwater three-spined stickleback Gasterosteus aculeatus: adaptations to a different buoyancy regime?

PubMed

Myhre, F; Klepaker, T

2009-11-01

Several factors related to buoyancy were compared between one marine and two freshwater populations of three-spined stickleback Gasterosteus aculeatus. Fish from all three populations had buoyancy near to neutral to the ambient water. This showed that neither marine nor freshwater G. aculeatus used swimming and hydrodynamic lift to prevent sinking. Comparing the swimbladder volumes showed that freshwater completely plated G. aculeatus had a significantly larger swimbladder volume than both completely plated marine and low-plated freshwater G. aculeatus. Furthermore, body tissue density was lower in low-plated G. aculeatus than in the completely plated marine and freshwater fish. The results show that G. aculeatus either reduce tissue density or increase swimbladder volume to adapt to lower water density. Mass measurements of lateral plates and pelvis showed that loss of body armour in low-plated G. aculeatus could explain the tissue density difference between low-plated and completely plated G. aculeatus. This suggests that the common occurrence of plate and armour reduction in freshwater G. aculeatus populations can be an adaptation to a lower water density.

Predicting local adaptation in fragmented plant populations: implications for restoration genetics

PubMed Central

Pickup, Melinda; Field, David L; Rowell, David M; Young, Andrew G

2012-01-01

Understanding patterns and correlates of local adaptation in heterogeneous landscapes can provide important information in the selection of appropriate seed sources for restoration. We assessed the extent of local adaptation of fitness components in 12 population pairs of the perennial herb Rutidosis leptorrhynchoides (Asteraceae) and examined whether spatial scale (0.7–600 km), environmental distance, quantitative (QST) and neutral (FST) genetic differentiation, and size of the local and foreign populations could predict patterns of adaptive differentiation. Local adaptation varied among populations and fitness components. Including all population pairs, local adaptation was observed for seedling survival, but not for biomass, while foreign genotype advantage was observed for reproduction (number of inflorescences). Among population pairs, local adaptation increased with QST and local population size for biomass. QST was associated with environmental distance, suggesting ecological selection for phenotypic divergence. However, low FST and variation in population structure in small populations demonstrates the interaction of gene flow and drift in constraining local adaptation in R. leptorrhynchoides. Our study indicates that for species in heterogeneous landscapes, collecting seed from large populations from similar environments to candidate sites is likely to provide the most appropriate seed sources for restoration. PMID:23346235

Fast digital zooming system using directionally adaptive image interpolation and restoration.

PubMed

Kang, Wonseok; Jeon, Jaehwan; Yu, Soohwan; Paik, Joonki

2014-01-01

This paper presents a fast digital zooming system for mobile consumer cameras using directionally adaptive image interpolation and restoration methods. The proposed interpolation algorithm performs edge refinement along the initially estimated edge orientation using directionally steerable filters. Either the directionally weighted linear or adaptive cubic-spline interpolation filter is then selectively used according to the refined edge orientation for removing jagged artifacts in the slanted edge region. A novel image restoration algorithm is also presented for removing blurring artifacts caused by the linear or cubic-spline interpolation using the directionally adaptive truncated constrained least squares (TCLS) filter. Both proposed steerable filter-based interpolation and the TCLS-based restoration filters have a finite impulse response (FIR) structure for real time processing in an image signal processing (ISP) chain. Experimental results show that the proposed digital zooming system provides high-quality magnified images with FIR filter-based fast computational structure.

Adaptive eigenspace method for inverse scattering problems in the frequency domain

NASA Astrophysics Data System (ADS)

Grote, Marcus J.; Kray, Marie; Nahum, Uri

2017-02-01

A nonlinear optimization method is proposed for the solution of inverse scattering problems in the frequency domain, when the scattered field is governed by the Helmholtz equation. The time-harmonic inverse medium problem is formulated as a PDE-constrained optimization problem and solved by an inexact truncated Newton-type iteration. Instead of a grid-based discrete representation, the unknown wave speed is projected to a particular finite-dimensional basis of eigenfunctions, which is iteratively adapted during the optimization. Truncating the adaptive eigenspace (AE) basis at a (small and slowly increasing) finite number of eigenfunctions effectively introduces regularization into the inversion and thus avoids the need for standard Tikhonov-type regularization. Both analytical and numerical evidence underpins the accuracy of the AE representation. Numerical experiments demonstrate the efficiency and robustness to missing or noisy data of the resulting adaptive eigenspace inversion method.

Development and design of flexible Fowler flaps for an adaptive wing

NASA Astrophysics Data System (ADS)

Monner, Hans P.; Hanselka, Holger; Breitbach, Elmar J.

1998-06-01

Civil transport airplanes fly with fixed geometry wings optimized only for one design point described by altitude, Mach number and airplane weight. These parameters vary continuously during flight, to which means the wing geometry seldom is optimal. According to aerodynamic investigations a chordwide variation of the wing camber leads to improvements in operational flexibility, buffet boundaries and performance resulting in reduction of fuel consumption. A spanwise differential camber variation allows to gain control over spanwise lift distributions reducing wing root bending moments. This paper describes the design of flexible Fowler flaps for an adaptive wing to be used in civil transport aircraft that allows both a chordwise as well as spanwise differential camber variation during flight. Since both lower and upper skins are flexed by active ribs, the camber variation is achieved with a smooth contour and without any additional gaps.

KSC-2011-6345

NASA Image and Video Library

2011-08-10

CAPE CANAVERAL, Fla. -- At Astrotech Space Operation's payload processing facility in Titusville, Fla., NASA's Gravity Recovery and Interior Laboratory-A (GRAIL-A) lunar probe is lifted from its workstand. The spacecraft will be transferred to the spacecraft adapter ring, at left, where GRAIL-B is already secured. After the twin GRAIL spacecraft are attached to the adapter ring in their side-by-side launch configuration, they will be transported to the launch pad. GRAIL will fly in tandem orbits around the moon for several months to measure its gravity field. GRAIL's primary science objectives are to determine the structure of the lunar interior, from crust to core, and to advance understanding of the thermal evolution of the moon. Launch aboard a United Launch Alliance Delta II rocket from Space Launch Complex 17B on Cape Canaveral Air Force Station is scheduled for Sept. 8. For more information, visit http://www.nasa.gov/grail. Photo credit: NASA/Jim Grossmann

KSC-2011-6346

NASA Image and Video Library

2011-08-10

CAPE CANAVERAL, Fla. -- At Astrotech Space Operation's payload processing facility in Titusville, Fla., NASA's Gravity Recovery and Interior Laboratory-A (GRAIL-A) lunar probe is lifted from its workstand and across the clean room toward the spacecraft adapter ring, at left, where GRAIL-B is already secured. After the twin GRAIL spacecraft are attached to the adapter ring in their side-by-side launch configuration, they will be transported to the launch pad. GRAIL will fly in tandem orbits around the moon for several months to measure its gravity field. GRAIL's primary science objectives are to determine the structure of the lunar interior, from crust to core, and to advance understanding of the thermal evolution of the moon. Launch aboard a United Launch Alliance Delta II rocket from Space Launch Complex 17B on Cape Canaveral Air Force Station is scheduled for Sept. 8. For more information, visit http://www.nasa.gov/grail. Photo credit: NASA/Jim Grossmann

Design and analysis of lifting tool assemblies to lift different engine block

NASA Astrophysics Data System (ADS)

Sawant, Arpana; Deshmukh, Nilaj N.; Chauhan, Santosh; Dabhadkar, Mandar; Deore, Rupali

2017-07-01

Engines block are required to be lifted from one place to another while they are being processed. The human effort required for this purpose is more and also the engine block may get damaged if it is not handled properly. There is a need for designing a proper lifting tool which will be able to conveniently lift the engine block and place it at the desired position without any accident and damage to the engine block. In the present study lifting tool assemblies are designed and analyzed in such way that it may lift different categories of engine blocks. The lifting tool assembly consists of lifting plate, lifting ring, cap screws and washers. A parametric model and assembly of Lifting tool is done in 3D modelling software CREO 2.0 and analysis is carried out in ANSYS Workbench 16.0. A test block of weight equivalent to that of an engine block is considered for the purpose of analysis. In the preliminary study, without washer the stresses obtained on the lifting tool were more than the safety margin. In the present design, washers were used with appropriate dimensions which helps to bring down the stresses on the lifting tool within the safety margin. Analysis is carried out to verify that tool design meets the ASME BTH-1 required safety margin.

Investigation of Maximum Blade Loading Capability of Lift-Offset Rotors

NASA Technical Reports Server (NTRS)

Yeo, Hyeonsoo; Johnson, Wayne

2013-01-01

Maximum blade loading capability of a coaxial, lift-offset rotor is investigated using a rotorcraft configuration designed in the context of short-haul, medium-size civil and military missions. The aircraft was sized for a 6600-lb payload and a range of 300 nm. The rotor planform and twist were optimized for hover and cruise performance. For the present rotor performance calculations, the collective pitch angle is progressively increased up to and through stall with the shaft angle set to zero. The effects of lift offset on rotor lift, power, controls, and blade airloads and structural loads are examined. The maximum lift capability of the coaxial rotor increases as lift offset increases and extends well beyond the McHugh lift boundary as the lift potential of the advancing blades are fully realized. A parametric study is conducted to examine the differences between the present coaxial rotor and the McHugh rotor in terms of maximum lift capabilities and to identify important design parameters that define the maximum lift capability of the rotor. The effects of lift offset on rotor blade airloads and structural loads are also investigated. Flap bending moment increases substantially as lift offset increases to carry the hub roll moment even at low collective values. The magnitude of flap bending moment is dictated by the lift-offset value (hub roll moment) but is less sensitive to collective and speed.

Atypicalities in Perceptual Adaptation in Autism Do Not Extend to Perceptual Causality

PubMed Central

Karaminis, Themelis; Turi, Marco; Neil, Louise; Badcock, Nicholas A.; Burr, David; Pellicano, Elizabeth

2015-01-01

A recent study showed that adaptation to causal events (collisions) in adults caused subsequent events to be less likely perceived as causal. In this study, we examined if a similar negative adaptation effect for perceptual causality occurs in children, both typically developing and with autism. Previous studies have reported diminished adaptation for face identity, facial configuration and gaze direction in children with autism. To test whether diminished adaptive coding extends beyond high-level social stimuli (such as faces) and could be a general property of autistic perception, we developed a child-friendly paradigm for adaptation of perceptual causality. We compared the performance of 22 children with autism with 22 typically developing children, individually matched on age and ability (IQ scores). We found significant and equally robust adaptation aftereffects for perceptual causality in both groups. There were also no differences between the two groups in their attention, as revealed by reaction times and accuracy in a change-detection task. These findings suggest that adaptation to perceptual causality in autism is largely similar to typical development and, further, that diminished adaptive coding might not be a general characteristic of autism at low levels of the perceptual hierarchy, constraining existing theories of adaptation in autism. PMID:25774507

Lift truck safety review

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

Cadwallader, L.C.

1997-03-01

This report presents safety information about powered industrial trucks. The basic lift truck, the counterbalanced sit down rider truck, is the primary focus of the report. Lift truck engineering is briefly described, then a hazard analysis is performed on the lift truck. Case histories and accident statistics are also given. Rules and regulations about lift trucks, such as the US Occupational Safety an Health Administration laws and the Underwriter`s Laboratories standards, are discussed. Safety issues with lift trucks are reviewed, and lift truck safety and reliability are discussed. Some quantitative reliability values are given.

Foot positioning instruction, initial vertical load position and lifting technique: effects on low back loading.

PubMed

Kingma, Idsart; Bosch, Tim; Bruins, Louis; van Dieën, Jaap H

2004-10-22

This study investigated the effects of initial load height and foot placement instruction in four lifting techniques: free, stoop (bending the back), squat (bending the knees) and a modified squat technique (bending the knees and rotating them outward). A 2D dynamic linked segment model was combined with an EMG assisted trunk muscle model to quantify kinematics and low back loading in 10 subjects performing 19 different lifting movements, using 10.5 kg boxes without handles. When lifting from a 0.05 m height with the feet behind the box, squat lifting resulted in 19.9% (SD 8.7%) higher net moments (p < 0.001) and 17.0% (SD 13.2%) higher compression forces (p < 0.01) than stoop lifting. This effect was reduced to 12.8% (SD 10.7%) for moments and a non-significant 7.4% (SD 16.0%) for compression forces when lifting with the feet beside the box and it disappeared when lifting from 0.5 m height. Differences between squat and stoop lifts, as well as the interaction with lifting height, could to a large extent be explained by changes in the horizontal L5/S1 intervertebral joint position relative to the load, the upper body acceleration, and lumbar flexion. Rotating the knees outward during squat lifts resulted in moments and compression forces that were smaller than in squat lifting but larger than in stoop lifting. Shear forces were small ( < 300 N) at the L4/L5 joint and substantial (1100 - 1400 N) but unaffected by lifting technique at the L5/S1 joint. The present results show that the effects of lifting technique on low back loading depend on the task context.

Portable source identification device

NASA Astrophysics Data System (ADS)

Andersen, Eric S.; Samuel, Todd J.; Gervais, Kevin L.

2005-05-01

U.S. Customs and Border Protection (CBP) is the primary enforcement agency protecting the nation"s ports of entry. CBP is enhancing its capability to interdict the illicit import of nuclear and radiological materials and devices that may be used by terrorists. Pacific Northwest National Laboratory (PNNL) is providing scientific and technical support to CBP in their goal to enable rapid deployment of nuclear and radiation detection systems at U. S. ports of entry to monitor 100% of the incoming international traffic and cargo while not adversely impacting the operations or throughput of the ports. As the deployment of radiation detection systems proceeds, there is a need to adapt the baseline radiation portal monitor (RPM) system technology to operations at these diverse ports of entry. When screening produces an alarm in the primary inspection RPM, the alarming vehicle is removed from the flow of commerce and the alarm is typically confirmed in a secondary inspection RPM. The portable source identification device (PSID) is a radiation sensor panel (RSP), based on thallium-doped sodium iodide (NaI(Tl)) scintillation detector and gamma spectroscopic analysis hardware and software, mounted on a scissor lift on a small truck. The lift supports a box containing a commercial off-the-shelf (COTS) sodium iodide detector that provides real-time isotopic identification, including neutron detectors to interdict Weapons of Mass Destruction (WMD) and radiation dispersion devices (RDD). The scissor lift will lower the detectors to within a foot off the ground and raise them to approximately 24 feet (7.3 m) in the air, allowing a wide vertical scanning range.

Analysis of Low-Speed Stall Aerodynamics of a Swept Wing with Seamless Flaps

NASA Technical Reports Server (NTRS)

Bui, Trong T.

2016-01-01

Computational fluid dynamics (CFD) analysis was conducted to study the low-speed stall aerodynamics of a Gulfstream G-III airplane (Gulfstream Aerospace Corporation, Savannah, Georgia) swept wing modified with an experimental seamless, compliant flap called the Adaptive Compliant Trailing Edge (ACTE) flap. The stall characteristics of the modified ACTE wing were analyzed and compared with the unmodified, clean wing at the flight speed of 120 knots and altitude of 2300 feet above mean sea level, in free air as well as in ground effect. A polyhedral finite-volume unstructured full Navier-Stokes CFD code, STAR-CCM (registered trademark) plus (CD-adapco [Computational Dynamics Limited, United Kingdom, and Analysis & Design Application Co., United States]), was used. Steady Reynolds-averaged Navier-Stokes CFD simulations were conducted for a clean wing and the ACTE wings at various ACTE deflection angles in free air (-2 degrees, 15 degrees, and 30 degrees) as well as in ground effect (15 degrees and 30 degrees). Solution sensitivities to grid densities were examined. In free air, the ACTE wings are predicted to stall at lower angles of attack than the clean wing. In ground effect, all wings are predicted to stall at lower angles of attack than the corresponding wings in free air. Even though the lift curves are higher in ground effect than in free air, the maximum lift coefficients for all wings are lower in ground effect. Finally, the lift increase due to ground effect for the ACTE wing is predicted to be less than the clean wing.

AORN Ergonomic Tool 6: lifting and carrying supplies and equipment in the perioperative setting.

PubMed

Waters, Thomas; Baptiste, Andrea; Short, Manon; Plante-Mallon, Lori; Nelson, Audrey

2011-08-01

Perioperative team members often are required to lift and carry heavy supplies and equipment into and around the OR; this includes lifting equipment such as hand tables, fluoroscopy boards, stirrups, Wilson frames, irrigation containers for lithotripsy, and heavy instrument pans. Lifting heavy objects creates considerable risk for musculoskeletal injuries to the back and shoulders. AORN Ergonomic Tool 6: Lifting and Carrying Supplies and Equipment in the Perioperative Setting can help caregivers evaluate lifting and carrying tasks and take measures to protect themselves from injury. Caregivers can use the revised National Institute for Occupational Safety and Health lifting equation to assess whether a specific lifting task can be performed safely. Published by Elsevier Inc.

KSC-00pp1387

NASA Image and Video Library

2000-09-07

In the Space Station Processing Facility, the Integrated Truss Structure Z1, an element of the International Space Station, is lifted for moving to another stand to check its weight and balance. The Z1 truss is the first of 10 trusses that will become the backbone of the Space Station, eventually stretching the length of a football field. Along with its companion payload, the third Pressurized Mating Adapter, the Z1 is scheduled to be launched aboard Space Shuttle Discovery Oct. 5 at 9:38 p.m. EDT. The launch will be the 100th in the Shuttle program

Wind tunnel wall interference (January 1980 - May 1988): A selected, annotated bibliography

NASA Technical Reports Server (NTRS)

Tuttle, Marie H.; Cole, Karen L.

1988-01-01

This selected bibliography lists 423 entries on the subject of wall interference during testing in wind tunnels. It is the third in a series of bibliographies on the subject. The first, NASA TM-87639, August 1986, is concerned with the reduction of wall interference by the use of adaptive walls. The second, NASA TP-89066, December 1986, is on wall interference in V/STOL and high lift testing. This, the third in the series, covers the wall interference literature published during the period January 1980 through May 1988, generally excluding those topics covered in the first two parts.

The Z1 truss is moved to check weight and balance

NASA Technical Reports Server (NTRS)

2000-01-01

In the Space Station Processing Facility, the Integrated Truss Structure Z1, an element of the International Space Station, is lifted for moving to another stand to check its weight and balance. The Z1 truss is the first of 10 trusses that will become the backbone of the Space Station, eventually stretching the length of a football field. Along with its companion payload, the third Pressurized Mating Adapter, the Z1 is scheduled to be launched aboard Space Shuttle Discovery Oct. 5 at 9:38 p.m. EDT. The launch will be the 100th in the Shuttle program.

Lift estimation of Half-Rotating Wing in hovering flight

NASA Astrophysics Data System (ADS)

Wang, X. Y.; Dong, Y. P.; Qiu, Z. Z.; Zhang, Y. Q.; Shan, J. H.

2016-11-01

Half-Rotating Wing (HRW) is a new kind of flapping wing system with rotating flapping instead of oscillating flapping. Estimating approach of hovering lift which generated in hovering flight was important theoretical foundation to design aircraft using HRW. The working principle of HRW based on Half-Rotating Mechanism (HRM) was firstly introduced in this paper. Generating process of lift by HRW was also given. The calculating models of two lift mechanisms for HRW, including Lift of Flow Around Wing (LFAW) and Lift of Flow Dragging Wing (LFDW), were respectively established. The lift estimating model of HRW was further deduced, by which hovering lift for HRW with different angular velocity could be calculated. Case study using XFLOW software simulation indicates that the above estimating method was effective and feasible to predict roughly the hovering lift for a new HRW system.

Evaluation of ceiling lifts in health care settings: patient outcome and perceptions.

PubMed

Alamgir, Hasanat; Li, Olivia Wei; Gorman, Erin; Fast, Catherine; Yu, Shicheng; Kidd, Catherine

2009-09-01

Ceiling lifts have been introduced into health care settings to reduce manual patient lifting and thus occupational injuries. Although growing evidence supports the effectiveness of ceiling lifts, a paucity of research links indicators, such as quality of patient care or patient perceptions, to the use of these transfer devices. This study explored the relationship between ceiling lift coverage rates and measures of patient care quality (e.g., incidence of facility-acquired pressure ulcers, falls, urinary infections, urinary incontinence, and assaults [patient to staff] in acute and long-term care facilities), as well as patient perceptions of satisfaction with care received while using ceiling lifts in a complex care facility. Qualitative semi-structured interviews were used to generate data. A significant inverse relationship was found between pressure ulcer rates and ceiling lift coverage; however, this effect was attenuated by year. No significant relationships existed between ceiling lift coverage and patient outcome indicators after adding the "year" variable to the model. Patients generally approved of the use of ceiling lifts and recognized many of the benefits. Ceiling lifts are not detrimental to the quality of care received by patients, and patients prefer being transferred by ceiling lifts. The relationship between ceiling lift coverage and pressure ulcer rates warrants further investigation. Copyright (c) 2009, SLACK Incorporated.

Relative importance of expertise, lifting height and weight lifted on posture and lumbar external loading during a transfer task in manual material handling.

PubMed

Plamondon, André; Larivière, Christian; Delisle, Alain; Denis, Denys; Gagnon, Denis

2012-01-01

The objective of this study was to measure the effect size of three important factors in manual material handling, namely expertise, lifting height and weight lifted. The effect of expertise was evaluated by contrasting 15 expert and 15 novice handlers, the effect of the weight lifted with a 15-kg box and a 23-kg box and the effect of lifting height with two different box heights: ground level and a 32 cm height. The task consisted of transferring a series of boxes from a conveyor to a hand trolley. Lifting height and weight lifted had more effect size than expertise on external back loading variables (moments) while expertise had low impact. On the other hand, expertise showed a significant effect of posture variables on the lumbar spine and knees. All three factors are important, but for a reduction of external back loading, the focus should be on the lifting height and weight lifted. The objective was to measure the effect size of three important factors in a transfer of boxes from a conveyor to a hand trolley. Lifting height and weight lifted had more effect size than expertise on external back loading variables but expertise was a major determinant in back posture.

78 FR 79599 - Airworthiness Directives; Various Aircraft Equipped With Wing Lift Struts

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-31

... Airworthiness Directives; Various Aircraft Equipped With Wing Lift Struts AGENCY: Federal Aviation... wing lift struts. The list of affected airplanes in the Applicability section is incorrect. Several... wing lift struts for corrosion; repetitively inspecting the wing lift strut forks for cracks; replacing...

Understanding and applying principles of social cognition and decision making in adaptive environmental governance.

PubMed

DeCaro, Daniel A; Arnol, Craig Anthony Tony; Boama, Emmanuel Frimpong; Garmestani, Ahjond S

2017-03-01

Environmental governance systems are under greater pressure to adapt and to cope with increased social and ecological uncertainty from stressors like climate change. We review principles of social cognition and decision making that shape and constrain how environmental governance systems adapt. We focus primarily on the interplay between key decision makers in society and legal systems. We argue that adaptive governance must overcome three cooperative dilemmas to facilitate adaptation: (1) encouraging collaborative problem solving, (2) garnering social acceptance and commitment, and (3) cultivating a culture of trust and tolerance for change and uncertainty. However, to do so governance systems must cope with biases in people's decision making that cloud their judgment and create conflict. These systems must also satisfy people's fundamental needs for self-determination, fairness, and security, ensuring that changes to environmental governance are perceived as legitimate, trustworthy, and acceptable. We discuss the implications of these principles for common governance solutions (e.g., public participation, enforcement) and conclude with methodological recommendations. We outline how scholars can investigate the social cognitive principles involved in cases of adaptive governance.

Understanding and applying principles of social cognition and decision making in adaptive environmental governance

PubMed Central

DeCaro, Daniel A.; Arnol, Craig Anthony (Tony); Boama, Emmanuel Frimpong; Garmestani, Ahjond S.

2018-01-01

Environmental governance systems are under greater pressure to adapt and to cope with increased social and ecological uncertainty from stressors like climate change. We review principles of social cognition and decision making that shape and constrain how environmental governance systems adapt. We focus primarily on the interplay between key decision makers in society and legal systems. We argue that adaptive governance must overcome three cooperative dilemmas to facilitate adaptation: (1) encouraging collaborative problem solving, (2) garnering social acceptance and commitment, and (3) cultivating a culture of trust and tolerance for change and uncertainty. However, to do so governance systems must cope with biases in people’s decision making that cloud their judgment and create conflict. These systems must also satisfy people’s fundamental needs for self-determination, fairness, and security, ensuring that changes to environmental governance are perceived as legitimate, trustworthy, and acceptable. We discuss the implications of these principles for common governance solutions (e.g., public participation, enforcement) and conclude with methodological recommendations. We outline how scholars can investigate the social cognitive principles involved in cases of adaptive governance. PMID:29780425

Anisotropic norm-oriented mesh adaptation for a Poisson problem

NASA Astrophysics Data System (ADS)

Brèthes, Gautier; Dervieux, Alain

2016-10-01

We present a novel formulation for the mesh adaptation of the approximation of a Partial Differential Equation (PDE). The discussion is restricted to a Poisson problem. The proposed norm-oriented formulation extends the goal-oriented formulation since it is equation-based and uses an adjoint. At the same time, the norm-oriented formulation somewhat supersedes the goal-oriented one since it is basically a solution-convergent method. Indeed, goal-oriented methods rely on the reduction of the error in evaluating a chosen scalar output with the consequence that, as mesh size is increased (more degrees of freedom), only this output is proven to tend to its continuous analog while the solution field itself may not converge. A remarkable quality of goal-oriented metric-based adaptation is the mathematical formulation of the mesh adaptation problem under the form of the optimization, in the well-identified set of metrics, of a well-defined functional. In the new proposed formulation, we amplify this advantage. We search, in the same well-identified set of metrics, the minimum of a norm of the approximation error. The norm is prescribed by the user and the method allows addressing the case of multi-objective adaptation like, for example in aerodynamics, adaptating the mesh for drag, lift and moment in one shot. In this work, we consider the basic linear finite-element approximation and restrict our study to L2 norm in order to enjoy second-order convergence. Numerical examples for the Poisson problem are computed.

The effect of selection environment on the probability of parallel evolution.

PubMed

Bailey, Susan F; Rodrigue, Nicolas; Kassen, Rees

2015-06-01

Across the great diversity of life, there are many compelling examples of parallel and convergent evolution-similar evolutionary changes arising in independently evolving populations. Parallel evolution is often taken to be strong evidence of adaptation occurring in populations that are highly constrained in their genetic variation. Theoretical models suggest a few potential factors driving the probability of parallel evolution, but experimental tests are needed. In this study, we quantify the degree of parallel evolution in 15 replicate populations of Pseudomonas fluorescens evolved in five different environments that varied in resource type and arrangement. We identified repeat changes across multiple levels of biological organization from phenotype, to gene, to nucleotide, and tested the impact of 1) selection environment, 2) the degree of adaptation, and 3) the degree of heterogeneity in the environment on the degree of parallel evolution at the gene-level. We saw, as expected, that parallel evolution occurred more often between populations evolved in the same environment; however, the extent of parallel evolution varied widely. The degree of adaptation did not significantly explain variation in the extent of parallelism in our system but number of available beneficial mutations correlated negatively with parallel evolution. In addition, degree of parallel evolution was significantly higher in populations evolved in a spatially structured, multiresource environment, suggesting that environmental heterogeneity may be an important factor constraining adaptation. Overall, our results stress the importance of environment in driving parallel evolutionary changes and point to a number of avenues for future work for understanding when evolution is predictable. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Feasibility study of modern airships, phase 1. Volume 2: Parametric analysis (task 3). [lift, weight (mass)

NASA Technical Reports Server (NTRS)

Lancaster, J. W.

1975-01-01

Various types of lighter-than-air vehicles from fully buoyant to semibuoyant hybrids were examined. Geometries were optimized for gross lifting capabilities for ellipsoidal airships, modified delta planform lifting bodies, and a short-haul, heavy-lift vehicle concept. It is indicated that: (1) neutrally buoyant airships employing a conservative update of materials and propulsion technology provide significant improvements in productivity; (2) propulsive lift for VTOL and aerodynamic lift for cruise significantly improve the productivity of low to medium gross weight ellipsoidal airships; and (3) the short-haul, heavy-lift vehicle, consisting of a simple combination of an ellipsoidal airship hull and existing helicopter componentry, provides significant potential for low-cost, near-term applications for ultra-heavy lift missions.

Evaluation of ceiling lifts: transfer time, patient comfort and staff perceptions.

PubMed

Alamgir, Hasanat; Li, Olivia Wei; Yu, Shicheng; Gorman, Erin; Fast, Catherine; Kidd, Catherine

2009-09-01

Mechanical lifting devices have been developed to reduce healthcare worker injuries related to patient handling. The purpose of this study was to evaluate ceiling lifts in comparison to floor lifts based on transfer time, patient comfort and staff perceptions in three long-term care facilities with varying ceiling lift coverage. The time required to transfer or reposition patients along with patient comfort levels were recorded for 119 transfers. Transfers performed with ceiling lifts required on average less time (bed to chair transfers: 156.9 seconds for ceiling lift, 273.6 seconds for floor lift) and were found to be more comfortable for patients. In the three facilities, 143 healthcare workers were surveyed on their perceptions of patient handling tasks and equipment. For both transferring and repositioning tasks, staff preferred to use ceiling lifts and also found them to be less physically demanding. Further investigation is needed on repositioning tasks to ensure safe practice.

DNA Profiles from Fingerprint Lifts-Enhancing the Evidential Value of Fingermarks Through Successful DNA Typing.

PubMed

Subhani, Zuhaib; Daniel, Barbara; Frascione, Nunzianda

2018-05-25

This study evaluated the compatibility of the most common enhancement methods and lifting techniques with DNA profiling. Emphasis is placed on modern lifting techniques (i.e., gelatin lifters and Isomark™) and historical fingerprint lifts for which limited research has been previously conducted. A total of 180 fingerprints were deposited on a glass surface, enhanced, lifted, and processed for DNA typing. DNA could be extracted and profiled for all the powders and lifts tested and from both groomed fingerprints and natural prints with no significant difference in the percentage of profile recovered. DNA profiles could also be obtained from historical fingerprint lifts (79.2% of 72 lifts) with one or more alleles detected. These results demonstrate the compatibility between different powder/lift combinations and DNA profiling therefore augmenting the evidential value of fingerprints in forensic casework. © 2018 American Academy of Forensic Sciences.

Isokinetic and isometric lifting capacity of Chinese in relation to the physical demand of job.

PubMed

Luk, K D K; Lu, W W; Kwan, W W; Hu, Y; Wong, Y W; Law, K K P; Leong, J C Y

2003-03-01

The aim of the study was to formulate normative data for the lifting capacities of a normal Chinese population, in order to establish a basic foundation for further studies and to investigate the relationship between individual attributes including age, gender, height, weight, job physical demand and each type of lifting capacity. Isokinetic and isometric lifting strength at low, waist and shoulder assessment levels were measured using the LIDO Workset II based on a sample of 93 normal Chinese adults (63 men and 30 women) between the ages of 21-51. The 50th percentile score for adult Chinese female's lifting strength was 17.71% lower than the American female while the adult Chinese male's lifting strength was 14.94% lower than the American male. Lifting forces were higher in the 20-40 year age group. The isometric work mode had considerable impact on the lifting capacities, with shoulder level having the highest lifting capacities. The gender and body weight had a significant positive correlation to lifting capacity while job physical demand had a moderate correlation. Age and body heights were weakly correlated to lifting capacity. Copyright 2003 Elsevier Science Ltd.

Washington Geothermal Play Fairway Analysis Data From Potential Field Studies

DOE Data Explorer

Anderson, Megan; Ritzinger, Brent; Glen, Jonathan; Schermerhorn, William

2017-12-20

A recent study which adapts play fairway analysis (PFA) methodology to assess geothermal potential was conducted at three locations (Mount Baker, Mount St. Helens seismic zone, and Wind River valley) along the Washington Cascade Range (Forson et al. 2017). Potential field (gravity and magnetic) methods which can detect subsurface contrasts in physical properties, provides a means for mapping and modeling subsurface geology and structure. As part of the WA-Cascade PFA project, we performed potential field studies by collecting high-resolution gravity and ground-magnetic data, and rock property measurements to (1) identify and constrain fault geometries (2) constrain subsurface lithologic distribution (3) study fault interactions (4) identify areas favorable to hydrothermal flow, and ultimately (5) guide future geothermal exploration at each location.

EMG Activity of Selected Trunk and Hip Muscles During a Squat Lift: Effect of Varying the Lumbar Posture

DTIC Science & Technology

1990-01-01

8 Posterior Ligamentous System..........11 Stoop Lift vs. Squat Lift...............17 Kyphosis.....................18 Lordosis ...of EMG electrodes .. ........... . 27 3. Plot of the EMG activity (% MVIC) recorded during a squat lift with the lumbar spine in lordosis . . 31 4...during a squat lift with the lumbar spine in lordosis . . . 33 6. Plot of the EMG activity (% MDA) recorded during a squat lift with the lumbar spine in

21 CFR 880.5500 - AC-powered patient lift.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered patient lift. 880.5500 Section 880.5500... Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered device either fixed or mobile, used to lift and transport patients in the horizontal or other...

21 CFR 880.5500 - AC-powered patient lift.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false AC-powered patient lift. 880.5500 Section 880.5500... Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered device either fixed or mobile, used to lift and transport patients in the horizontal or other...

29 CFR 1926.753 - Hoisting and rigging.

Code of Federal Regulations, 2010 CFR

2010-07-01

... lift rigging procedure. (1) A multiple lift shall only be performed if the following criteria are met: (i) A multiple lift rigging assembly is used; (ii) A maximum of five members are hoisted per lift... multiple lift have been trained in these procedures in accordance with § 1926.761(c)(1). (v) No crane is...

The Selection of a Van Lift or a Scooter.

ERIC Educational Resources Information Center

Stevens, John H.

1990-01-01

This newsletter issue describes 3-wheeled scooters and van lifts that can assist a person with a disability to drive independently or have access to transportation. The section on van lifts compares hydraulic lifts and electric lifts, lists manufacturers, and offers an "assessment quiz" outlining factors to consider in selecting a van…

Aerodynamic characteristics of a propeller-powered high-lift semispan wing

NASA Technical Reports Server (NTRS)

Gentry, Garl L., Jr.; Takallu, M. A.; Applin, Zachary T.

1994-01-01

A small-scale semispan high-lift wing-flap system equipped under the wing with a turboprop engine assembly was tested in the LaRC 14- by 22-Foot Subsonic Tunnel. Experimental data were obtained for various propeller rotational speeds, nacelle locations, and nacelle inclinations. To isolate the effects of the high lift system, data were obtained with and without the flaps and leading-edge device. The effects of the propeller slipstream on the overall longitudinal aerodynamic characteristics of the wing-propeller assembly were examined. Test results indicated that the lift coefficient of the wing could be increased by the propeller slipstream when the rotational speed was increased and high-lift devices were deployed. Decreasing the nacelle inclination (increased pitch down) enhanced the lift performance of the system much more than varying the vertical or horizontal location of the nacelle. Furthermore, decreasing the nacelle inclination led to higher lift curve slope values, which indicated that the powered wing could sustain higher angles of attack near maximum lift performance. Any lift augmentation was accompanied by a drag penalty due to the increased wing lift.

Flexible Coordination in Resource-Constrained Domains

DTIC Science & Technology

1994-07-01

Experiments (TIEs) with planning technologies developed at both BBN (FMERG) and SRI ( SOCAP ). We have also exported scheduling support capabilities provided by...SRI’s SOCAP course of action (COA) plan generator. "* Development and demonstration of distributed, multi-level deployment scheduling - Through analysis...scheduler was adapted for integration with the SOCAP planning system to provide feedback on transportation feasibility during generation of the

Braking and Entering: A New CFO's Transition into A K-12 Urban School District

ERIC Educational Resources Information Center

Trautenberg, David Herbert

2016-01-01

In this autoethnography, I examine the challenges I faced as a private-to-public-sector novice CFO entering a resource-constrained 41-thousand-student K-12 urban school district in Colorado. This study chronicles how I deliberately slowed down my interactions within a complex adaptive system (CAS) through ethnographic interviewing to identify the…

Analysis of water use strategies of the desert riparian forest plant community in inland rivers of two arid regions in northwestern China

NASA Astrophysics Data System (ADS)

Chen, Y. N.; Li, W. H.; Zhou, H. H.; Chen, Y. P.; Hao, X. M.; Fu, A. H.; Ma, J. X.

2014-10-01

Studies of the water use of the desert riparian forest plant community in arid regions and analyses of the response and adaptive strategies of plants to environmental stress are of great significance to the formulation of effective ecological conservation and restoration strategies. Taking two inland rivers in the arid regions of northwestern China, downstream of the Tarim River and Heihe River Basin as the research target regions, this paper explored the stem water potential, sap flow, root hydraulic lift, and characteristics of plant water sources of the major constructive species in the desert riparian forest, Populus euphratica and Tamarix ramosissima. Specifically, this was accomplished by combining the monitoring of field physiological and ecological indicators, and the analysis of laboratory tests. Then, the water use differences of species in different ecological environments and their ecological significance were analyzed. This study indicated that: (1) in terms of water sources, Populus euphratica and Tamarix ramosissima mainly used deep subsoil water and underground water, but the plant root system in the downstream of the Tarim River was more diversified than that in the downstream of the Heihe River in water absorption, (2) in terms of water distribution, Populus euphratica root possessed hydraulic lift capacity, but Populus euphratica root in the downstream of the Tarim River presented stronger hydraulic lift capacity and more significant ecological effect of water redistribution, (3) in terms of water transport, the plants in the downstream of the Heihe River can adapt to the environment through the current limiting of branch xylem, while plants in the downstream of the Tarim River substantially increased the survival probability of the whole plant by sacrificing weak branches and improving the water acquisition capacity of dominant branches; and (4) in terms of water dissipation, the water use and consumption of Populus euphratica at night exhibited no significant difference, but the water use and consumption of Populus euphratica in the downstream of the Tarim River in the day was significantly higher than that in the downstream of the Heihe River, and the essential reason for this is the groundwater depth. The ecology in the downstream of the Heihe River has been in balance in the maintenance and development stage, while desert riparian forest plants in the downstream of the Tarim River are still in severe arid stress.

Frequency-domain beamformers using conjugate gradient techniques for speech enhancement.

PubMed

Zhao, Shengkui; Jones, Douglas L; Khoo, Suiyang; Man, Zhihong

2014-09-01

A multiple-iteration constrained conjugate gradient (MICCG) algorithm and a single-iteration constrained conjugate gradient (SICCG) algorithm are proposed to realize the widely used frequency-domain minimum-variance-distortionless-response (MVDR) beamformers and the resulting algorithms are applied to speech enhancement. The algorithms are derived based on the Lagrange method and the conjugate gradient techniques. The implementations of the algorithms avoid any form of explicit or implicit autocorrelation matrix inversion. Theoretical analysis establishes formal convergence of the algorithms. Specifically, the MICCG algorithm is developed based on a block adaptation approach and it generates a finite sequence of estimates that converge to the MVDR solution. For limited data records, the estimates of the MICCG algorithm are better than the conventional estimators and equivalent to the auxiliary vector algorithms. The SICCG algorithm is developed based on a continuous adaptation approach with a sample-by-sample updating procedure and the estimates asymptotically converge to the MVDR solution. An illustrative example using synthetic data from a uniform linear array is studied and an evaluation on real data recorded by an acoustic vector sensor array is demonstrated. Performance of the MICCG algorithm and the SICCG algorithm are compared with the state-of-the-art approaches.

Medication management strategies used by older adults with heart failure: A systems-based analysis.

PubMed

Mickelson, Robin S; Holden, Richard J

2017-09-01

Older adults with heart failure use strategies to cope with the constraining barriers impeding medication management. Strategies are behavioral adaptations that allow goal achievement despite these constraining conditions. When strategies do not exist, are ineffective or maladaptive, medication performance and health outcomes are at risk. While constraints to medication adherence are described in literature, strategies used by patients to manage medications are less well-described or understood. Guided by cognitive engineering concepts, the aim of this study was to describe and analyze the strategies used by older adults with heart failure to achieve their medication management goals. This mixed methods study employed an empirical strategies analysis method to elicit medication management strategies used by older adults with heart failure. Observation and interview data collected from 61 older adults with heart failure and 31 caregivers were analyzed using qualitative content analysis to derive categories, patterns and themes within and across cases. Data derived thematic sub-categories described planned and ad hoc methods of strategic adaptations. Stable strategies proactively adjusted the medication management process, environment, or the patients themselves. Patients applied situational strategies (planned or ad hoc) to irregular or unexpected situations. Medication non-adherence was a strategy employed when life goals conflicted with medication adherence. The health system was a source of constraints without providing commensurate strategies. Patients strived to control their medication system and achieve goals using adaptive strategies. Future patient self-mangement research can benefit from methods and theories used to study professional work, such as strategies analysis.

Summary of Lift and Lift/Cruise Fan Powered Lift Concept Technology

NASA Technical Reports Server (NTRS)

Cook, Woodrow L.

1993-01-01

A summary is presented of some of the lift and lift/cruise fan technology including fan performance, fan stall, ground effects, ingestion and thrust loss, design tradeoffs and integration, control effectiveness and several other areas related to vertical short takeoff and landing (V/STOL) aircraft conceptual design. The various subjects addressed, while not necessarily pertinent to specific short takeoff/vertical landing (STOVL) supersonic designs being considered, are of interest to the general field of lift and lift/cruise fan aircraft designs and may be of importance in the future. The various wind tunnel and static tests reviewed are: (1) the Doak VZ-4 ducted fan, (2) the 0.57 scale model of the Bell X-22 ducted fan aircraft, (3) the Avrocar, (4) the General Electric lift/cruise fan, (5) the vertical short takeoff and landing (V/STOL) lift engine configurations related to ingestion and consequent thrust loss, (6) the XV-5 and other fan-in-wing stall consideration, (7) hybrid configurations such as lift fan and lift/cruise fan or engines, and (8) the various conceptual design studies by air-frame contractors. Other design integration problems related to small and large V/STOL transport aircraft are summarized including lessons learned during more recent conceptual design studies related to a small executive V/STOL transport aircraft.

Constrained growth flips the direction of optimal phenological responses among annual plants.

PubMed

Lindh, Magnus; Johansson, Jacob; Bolmgren, Kjell; Lundström, Niklas L P; Brännström, Åke; Jonzén, Niclas

2016-03-01

Phenological changes among plants due to climate change are well documented, but often hard to interpret. In order to assess the adaptive value of observed changes, we study how annual plants with and without growth constraints should optimize their flowering time when productivity and season length changes. We consider growth constraints that depend on the plant's vegetative mass: self-shading, costs for nonphotosynthetic structural tissue and sibling competition. We derive the optimal flowering time from a dynamic energy allocation model using optimal control theory. We prove that an immediate switch (bang-bang control) from vegetative to reproductive growth is optimal with constrained growth and constant mortality. Increasing mean productivity, while keeping season length constant and growth unconstrained, delayed the optimal flowering time. When growth was constrained and productivity was relatively high, the optimal flowering time advanced instead. When the growth season was extended equally at both ends, the optimal flowering time was advanced under constrained growth and delayed under unconstrained growth. Our results suggests that growth constraints are key factors to consider when interpreting phenological flowering responses. It can help to explain phenological patterns along productivity gradients, and links empirical observations made on calendar scales with life-history theory. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

An experimental study of an airfoil with a bio-inspired leading edge device at high angles of attack

NASA Astrophysics Data System (ADS)

Mandadzhiev, Boris A.; Lynch, Michael K.; Chamorro, Leonardo P.; Wissa, Aimy A.

2017-09-01

Robust and predictable aerodynamic performance of unmanned aerial vehicles at the limits of their design envelope is critical for safety and mission adaptability. Deployable aerodynamic surfaces from the wing leading or trailing edges are often used to extend the aerodynamic envelope (e.g. slats and flaps). Birds have also evolved feathers at the leading edge (LE) of their wings, known as the alula, which enables them to perform high angles of attack maneuvers. In this study, a series of wind tunnel experiments are performed to quantify the effect of various deployment parameters of an alula-like LE device on the aerodynamic performance of a cambered airfoil (S1223) at stall and post stall conditions. The alula relative angle of attack, measured from the mean chord of the airfoil, is varied to modulate tip-vortex strength, while the alula deflection angle is varied to modulate the distance between the tip vortex and the wing surface. Integrated lift force measurements were collected at various alula-inspired device configurations. The effect of the alula-inspired device on the boundary layer velocity profile and turbulence intensity were investigated through hot-wire anemometer measurements. Results show that as alula deflection angle increases, the lift coefficient also increase especially at lower alula relative angles of attack. Moreover, at post stall wing angles of attack, the wake velocity deficit is reduced in the presence of alula device, confirming the mitigation of the wing adverse pressure gradient. The results are in strong agreement with measurements taken on bird wings showing delayed flow reversal and extended range of operational angles of attack. An engineered alula-inspired device has the potential to improve mission adaptability in small unmanned air vehicles during low Reynolds number flight.

Refined AFC-Enabled High-Lift System Integration Study

NASA Technical Reports Server (NTRS)

Hartwich, Peter M.; Shmilovich, Arvin; Lacy, Douglas S.; Dickey, Eric D.; Scalafani, Anthony J.; Sundaram, P.; Yadlin, Yoram

2016-01-01

A prior trade study established the effectiveness of using Active Flow Control (AFC) for reducing the mechanical complexities associated with a modern high-lift system without sacrificing aerodynamic performance at low-speed flight conditions representative of takeoff and landing. The current technical report expands on this prior work in two ways: (1) a refined conventional high-lift system based on the NASA Common Research Model (CRM) is presented that is more representative of modern commercial transport aircraft in terms of stall characteristics and maximum Lift/Drag (L/D) ratios at takeoff and landing-approach flight conditions; and (2) the design trade space for AFC-enabled high-lift systems is expanded to explore a wider range of options for improving their efficiency. The refined conventional high-lift CRM (HL-CRM) concept features leading edge slats and slotted trailing edge flaps with Fowler motion. For the current AFC-enhanced high lift system trade study, the refined conventional high-lift system is simplified by substituting simply-hinged trailing edge flaps for the slotted single-element flaps with Fowler motion. The high-lift performance of these two high-lift CRM variants is established using Computational Fluid Dynamics (CFD) solutions to the Reynolds-Averaged Navier-Stokes (RANS) equations. These CFD assessments identify the high-lift performance that needs to be recovered through AFC to have the CRM variant with the lighter and mechanically simpler high-lift system match the performance of the conventional high-lift system. In parallel to the conventional high-lift concept development, parametric studies using CFD guided the development of an effective and efficient AFC-enabled simplified high-lift system. This included parametric trailing edge flap geometry studies addressing the effects of flap chord length and flap deflection. As for the AFC implementation, scaling effects (i.e., wind-tunnel versus full-scale flight conditions) are addressed, as are AFC architecture aspects such as AFC unit placement, number AFC units, operating pressures, mass flow rates, and steady versus unsteady AFC applications. These efforts led to the development of a novel traversing AFC actuation concept which is efficient in that it reduces the AFC mass flow requirements by as much as an order of magnitude compared to previous AFC technologies, and it is predicted to be effective in driving the aerodynamic performance of a mechanical simplified high-lift system close to that of the reference conventional high-lift system. Conceptual system integration studies were conducted for the AFC-enhanced high-lift concept applied to a NASA Environmentally Responsible Aircraft (ERA) reference configuration, the so-called ERA-0003 concept. The results from these design integration assessments identify overall system performance improvement opportunities over conventional high-lift systems that suggest the viability of further technology maturation efforts for AFC-enabled high lift flap systems. To that end, technical challenges are identified associated with the application of AFC-enabled high-lift systems to modern transonic commercial transports for future technology maturation efforts.

21 CFR 880.5510 - Non-AC-powered patient lift.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Non-AC-powered patient lift. 880.5510 Section 880... Devices § 880.5510 Non-AC-powered patient lift. (a) Identification. A non-AC-powered patient lift is a hydraulic, battery, or mechanically powered device, either fixed or mobile, used to lift and transport a...

75 FR 27662 - Special Conditions: Boeing 747-468, Installation of a Medical Lift

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-18

...; Notice No. 25-99-11-SC] Special Conditions: Boeing 747-468, Installation of a Medical Lift AGENCY... Aviation, will have a novel or unusual design feature associated with the installation of a medical lift... modification includes the installation of a medical lift between the main deck and upper deck. The lift allows...

21 CFR 880.5510 - Non-AC-powered patient lift.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Non-AC-powered patient lift. 880.5510 Section 880... Devices § 880.5510 Non-AC-powered patient lift. (a) Identification. A non-AC-powered patient lift is a hydraulic, battery, or mechanically powered device, either fixed or mobile, used to lift and transport a...

The Six Track Scherzer Rolling Lift Bridge…Two double track spans ...

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

The Six Track Scherzer Rolling Lift Bridge…Two double track spans closed. One double-track span open. Photocopy of plate xvi in Scherzer Rolling Lift Bridge Company, Scherzer Rolling Lift Bridges. - New York, New Haven & Hartford Railroad, Fort Point Channel Rolling Lift Bridge, Spanning Fort Point Channel, Boston, Suffolk County, MA

Six-degree-of-freedom guidance and control-entry analysis of the HL-20

NASA Technical Reports Server (NTRS)

Powell, Richard W.

1993-01-01

The ability of the HL-20 lifting body to fly has been evaluated for an automated entry from atmospheric interface to landing. This evaluation was required to demonstrate that not only successful touchdown conditions would be possible for this low lift-to-drag-ratio vehicle, but also the vehicle would not exceed its design dynamic pressure limit of 400 psf during entry. This dynamic pressure constraint limit, coupled with limited available pitch-control authority at low supersonic speeds, restricts the available maneuvering capability for the HL-20 to acquire the runway. One result of this analysis was that this restrictive maneuvering capability does not allow the use of a model-following atmospheric entry-guidance algorithm, such as that used by the Space Shuttle, but instead requires a more adaptable guidance algorithm. Therefore, for this analysis, a predictor-corrector guidance algorithm was developed that would provide successful touchdown conditions while not violating the dynamic pressure constraint. A flight-control system was designed and incorporated, along with the predictor-corrector guidance algorithm, into a six-DOF simulation. which showed that the HL-20 remained controllable and could reach the landing site and execute a successful landing under all off-nominal conditions simulated.

Passive control of rotorcraft high-speed impulsive noise

NASA Astrophysics Data System (ADS)

Szulc, O.; Doerffer, P.; Tejero, F.

2016-10-01

A strong, normal shock wave, terminating a local supersonic area located at the tip of a helicopter blade, not only limits the aerodynamic performance, but also constitutes an origin of the High-Speed Impulsive (HSI) noise. The application of a passive control device (a shallow cavity covered by a perforated plate) just beneath the interaction region weakens the compression level, thus reducing the main source of the HSI noise. The numerical investigation based on the URANS approach and Bohning/Doerffer (BD) transpiration law (SPARC code) confirms a large potential of the new method. Two exemplary implementations, adapted to model helicopter rotors tested at NASA Ames facility in transonic conditions: Caradonna-Tung (lifting, transonic hover) and Caradonna-Laub-Tung (non-lifting, high-speed forward flight), demonstrate the possible gains in terms of the reduction of acoustic pressure fluctuations in the near-field of the blade tip. The CFD results are validated against the experimental data obtained for the reference configurations (no control), while the analysis of the passive control arrangement is based on a purely numerical research. The normal shock wave is effectively eliminated by the wall ventilation exerting a positive impact on the generated level of the HSI noise.

Hybrid state vector methods for structural dynamic and aeroelastic boundary value problems

NASA Technical Reports Server (NTRS)

Lehman, L. L.

1982-01-01

A computational technique is developed that is suitable for performing preliminary design aeroelastic and structural dynamic analyses of large aspect ratio lifting surfaces. The method proves to be quite general and can be adapted to solving various two point boundary value problems. The solution method, which is applicable to both fixed and rotating wing configurations, is based upon a formulation of the structural equilibrium equations in terms of a hybrid state vector containing generalized force and displacement variables. A mixed variational formulation is presented that conveniently yields a useful form for these state vector differential equations. Solutions to these equations are obtained by employing an integrating matrix method. The application of an integrating matrix provides a discretization of the differential equations that only requires solutions of standard linear matrix systems. It is demonstrated that matrix partitioning can be used to reduce the order of the required solutions. Results are presented for several example problems in structural dynamics and aeroelasticity to verify the technique and to demonstrate its use. These problems examine various types of loading and boundary conditions and include aeroelastic analyses of lifting surfaces constructed from anisotropic composite materials.

Design of a hydraulically-driven bionic folding wing.

PubMed

Zhang, Zhijun; Sun, Xuwei; Du, Pengyu; Sun, Jiyu; Wu, Yongfeng

2018-06-01

Membranous hind wings of the beetles can be folded under the elytra when they are at rest, and rotate and lift the elytra up only when they need to fly. This characteristic provides excellent flying capability and good environment adaptability. Inspired by the beetles, the new type of the bionic folding wing for the flapping wing Micro Air Vehicle (MAV) was designed. This flapping wing can be unfolded to get a sufficient lift in flight, and can be folded off flight to reduce the wing area and risk of the wing damage. The relationship between the internal pressures of the hydraulic system for the bionic wing folding varies and temperature was analyzed, the results show that the pressure within the system tends to increase with temperature, which proves the feasibility of the schematic design in theory. Stress analysis of the bionic wing was conducted, it was shown that stress distributions and deformation of the bionic wing under the positive and negative side loading are basically the same, which demonstrates that the strength of the bionic folding wing meets the requirements and further proves the feasibility of the schematic design. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

A wall interference assessment/correction system

NASA Technical Reports Server (NTRS)

Lo, Ching F.; Overby, Glenn; Qian, Cathy X.; Sickles, W. L.; Ulbrich, N.

1992-01-01

A Wall Signature method originally developed by Hackett has been selected to be adapted for the Ames 12-ft Wind Tunnel WIAC system in the project. This method uses limited measurements of the static pressure at the wall, in conjunction with the solid wall boundary condition, to determine the strength and distribution of singularities representing the test article. The singularities are used in turn for estimating blockage wall interference. The lifting interference will be treated separately by representing in a horseshoe vortex system for the model's lifting effects. The development and implementation of a working prototype will be completed, delivered and documented with a software manual. The WIAC code will be validated by conducting numerically simulated experiments rather than actual wind tunnel experiments. The simulations will be used to generate both free-air and confined wind-tunnel flow fields for each of the test articles over a range of test configurations. Specifically, the pressure signature at the test section wall will be computed for the tunnel case to provide the simulated 'measured' data. These data will serve as the input for the WIAC method--Wall Signature method. The performance of the WIAC method then may be evaluated by comparing the corrected data with those of the free-air simulation.

Human Mars Entry, Descent and Landing Architectures Study Overview

NASA Technical Reports Server (NTRS)

Polsgrove, Tara T.; Dwyer Cianciolo, Alicia

2016-01-01

Landing humans on Mars will require entry, descent and landing (EDL) capability beyond the current state of the art. Nearly twenty times more delivered payload and an order of magnitude improvement in precision landing capability will be necessary. Several EDL technologies capable of meeting the human class payload delivery requirements are being considered. The EDL technologies considered include low lift-to-drag vehicles like Hypersonic Inflatable Aerodynamic Decelerators (HIAD), Adaptable Deployable Entry and Placement Technology (ADEPT), and mid range lift-to-drag vehicles like rigid aeroshell configurations. To better assess EDL technology options and sensitivities to future human mission design variations, a series of design studies has been conducted. The design studies incorporate EDL technologies with conceptual payload arrangements defined by the Evolvable Mars Campaign to evaluate the integrated system with higher fidelity than have been performed to date. This paper describes the results of the design studies for a lander design using the HIAD, ADEPT and rigid shell entry technologies and includes system and subsystem design details including mass and power estimates. This paper will review the point design for three entry configurations capable of delivering a 20 t human class payload to the surface of Mars.

Further evaluation of the constrained least squares electromagnetic compensation method

NASA Technical Reports Server (NTRS)

Smith, William T.

1991-01-01

Technologies exist for construction of antennas with adaptive surfaces that can compensate for many of the larger distortions caused by thermal and gravitational forces. However, as the frequency and size of reflectors increase, the subtle surface errors become significant and degrade the overall electromagnetic performance. Electromagnetic (EM) compensation through an adaptive feed array offers means for mitigation of surface distortion effects. Implementation of EM compensation is investigated with the measured surface errors of the NASA 15 meter hoop/column reflector antenna. Computer simulations are presented for: (1) a hybrid EM compensation technique, and (2) evaluating the performance of a given EM compensation method when implemented with discretized weights.

High speed, precision motion strategies for lightweight structures

NASA Technical Reports Server (NTRS)

Book, Wayne J.

1989-01-01

Research on space telerobotics is summarized. Adaptive control experiments on the Robotic Arm, Large and Flexible (RALF) were preformed and are documented, along with a joint controller design for the Small Articulated Manipulator (SAM), which is mounted on the RALF. A control algorithm is described as a robust decentralized adaptive control based on a bounded uncertainty approach. Dynamic interactions between SAM and RALF are examined. Unstability of the manipulator is studied from the perspective that the inertial forces generated could actually be used to more rapidly damp out the flexible manipulator's vibration. Currently being studied is the modeling of the constrained dynamics of flexible arms.

77 FR 32644 - Medical Devices; Exemption From Premarket Notification: Wheelchair Elevator

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-01

... elevator devices commonly known as inclined platform lifts and vertical platform lifts. These devices are... inclined platform lifts and vertical platform lifts), classified under 21 CFR 890.3930. IV. Comments...

High lift selected concepts

NASA Technical Reports Server (NTRS)

Henderson, M. L.

1979-01-01

The benefits to high lift system maximum life and, alternatively, to high lift system complexity, of applying analytic design and analysis techniques to the design of high lift sections for flight conditions were determined and two high lift sections were designed to flight conditions. The influence of the high lift section on the sizing and economics of a specific energy efficient transport (EET) was clarified using a computerized sizing technique and an existing advanced airplane design data base. The impact of the best design resulting from the design applications studies on EET sizing and economics were evaluated. Flap technology trade studies, climb and descent studies, and augmented stability studies are included along with a description of the baseline high lift system geometry, a calculation of lift and pitching moment when separation is present, and an inverse boundary layer technique for pressure distribution synthesis and optimization.

Total Facelift: Forehead Lift, Midface Lift, and Neck Lift

PubMed Central

2015-01-01

Patients with thick skin mainly exhibit the aging processes of sagging, whereas patients with thin skin develop wrinkles or volume loss. Asian skin is usually thicker than that of Westerners; and thus, the sagging of skin due to aging, rather than wrinkling, is the chief problem to be addressed in Asians. Asian skin is also relatively large in area and thick, implying that the weight of tissue to be lifted is considerably heavier. These factors account for the difficulties in performing a facelift in Asians. Facelifts can be divided into forehead lift, midface lift, and lower face lift. These can be performed individually or with 2-3 procedures combined. PMID:25798381

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

NASA Technical Reports Server (NTRS)

1990-01-01

A preliminary study of a supersonic short takeoff and vertical landing (STOVL) fighter is presented. Three configurations (a lift plus lift/cruise concept, a hybrid fan vectored thrust concept, and a mixed flow vectored thrust concept) were initially investigated with one configuration selected for further design analysis. The selected configuration, the lift plus lift/cruise concept, was successfully integrated to accommodate the powered lift short takeoff and vertical landing requirements as well as the demanding supersonic cruise and point performance requirements. A supersonic fighter aircraft with a short takeoff and vertical landing capability using the lift plus lift/cruise engine concept seems a viable option for the next generation fighter.

Aerodynamic characteristics of a large-scale lift-engine fighter model with external swiveling lift-engines

NASA Technical Reports Server (NTRS)

Barrack, J. P.; Kirk, J. V.

1972-01-01

The aerodynamic characteristics of a six-engine (four lift, two lift-cruise) lift-engine model obtained in the Ames 40- by 80-foot wind tunnel are presented. The model was an approximate one-half scale representation of a lift-engine VTOL fighter aircraft with a variable-sweep wing. The four lift-engines were housed in the aft fuselage with the inlets located above the wing. Longitudinal and lateral-directional force and moment data are presented for a range of exhaust gas momentum ratios (thrust coefficients). Wind tunnel forward speed was varied from 0 to 140 knots corresponding to a maximum Reynolds number of 6.7 million. The data are presented without analysis.

77 FR 28488 - Drawbridge Operation Regulation; Upper Mississippi River, Hannibal, MO

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-15

... lifting cables that operate the lift span. This deviation allows the bridge to remain in the closed position while the lift cables are replaced. DATES: This deviation is effective from 9 a.m. to 3 p.m. on or... wire rope lifting cables that operate the lift span are replaced. The closure period will be from 9 a.m...

High-Lift Capability of Low Aspect Ratio Wings Utilizing Circulation Control and Upper Surface Blowing

DTIC Science & Technology

1980-07-01

span, ft (m) CD Drag coefficient, D/qS I CD Drag coefficient at zero lift CL Lift coefficient, L/qS CL Lift curve elope, aCL/aa I CL Maximum lift...recording on magnetic tape utilizing a Beckman 210 high-speed acquistion system. The wing-fuselage model was mounted in the test section such that...6, 7, and 8 show the tip sails have little impact on the zero or low-lift drag, but these j sails definitely influence the induced drag that is deve

Feasibility study of modern airships, phase 2. Volume 1: Heavy lift airship vehicle. Book 1: Overall study results

NASA Technical Reports Server (NTRS)

1976-01-01

A Heavy Lift Airship combining buoyant lift derived from a conventional helium-filled non-rigid airship hull with propulsive lift derived from conventional helicopter rotors was investigated. The buoyant lift essentially offsets the empty weight of the vehicle; thus the rotor thrust is available for useful load and to maneuver and control the vehicle. Such a vehicle is capable of providing a quantum increase in current vertical lifting capability. Certain critical deficiencies of past airships are significantly minimized or eliminated.

Analysis of squat and stoop dynamic liftings: muscle forces and internal spinal loads

PubMed Central

Bazrgari, Babak; Arjmand, Navid

2006-01-01

Despite the well-recognized role of lifting in back injuries, the relative biomechanical merits of squat versus stoop lifting remain controversial. In vivo kinematics measurements and model studies are combined to estimate trunk muscle forces and internal spinal loads under dynamic squat and stoop lifts with and without load in hands. Measurements were performed on healthy subjects to collect segmental rotations during lifts needed as input data in subsequent model studies. The model accounted for nonlinear properties of the ligamentous spine, wrapping of thoracic extensor muscles to take curved paths in flexion and trunk dynamic characteristics (inertia and damping) while subject to measured kinematics and gravity/external loads. A dynamic kinematics-driven approach was employed accounting for the spinal synergy by simultaneous consideration of passive structures and muscle forces under given posture and loads. Results satisfied kinematics and dynamic equilibrium conditions at all levels and directions. Net moments, muscle forces at different levels, passive (muscle or ligamentous) forces and internal compression/shear forces were larger in stoop lifts than in squat ones. These were due to significantly larger thorax, lumbar and pelvis rotations in stoop lifts. For the relatively slow lifting tasks performed in this study with the lowering and lifting phases each lasting ∼2 s, the effect of inertia and damping was not, in general, important. Moreover, posterior shift in the position of the external load in stoop lift reaching the same lever arm with respect to the S1 as that in squat lift did not influence the conclusion of this study on the merits of squat lifts over stoop ones. Results, for the tasks considered, advocate squat lifting over stoop lifting as the technique of choice in reducing net moments, muscle forces and internal spinal loads (i.e., moment, compression and shear force). PMID:17103232

Tolerability to prolonged lifting tasks. A validation of the recommended limits.

PubMed

Capodaglio, P; Bazzini, G

1997-01-01

Prolonged physical exertion is subjectively regulated by the perception of effort. This preliminary study was conducted to validate the use of subjective perceptions of effort in assessing objectively tolerable workloads for prolonged lifting tasks. Ten healthy male subjects tested their maximal lifting capacity (MLC) on a lift dynamometer (LidoLift, Loredan Biomed., West Sacramento, CA) and underwent incremental and 30-minute endurance lifting tests. Cardiorespiratory parameters were monitored with an oxygen uptake analyzer, mechanical parameters were calculated using a computerized dynamometer. Ratings of perceived exertion were given on Borg's 10-point scale. Physiological responses to repetitive lifting were matched with subjective perceptions. A single-variable statistical regression for power functions was performed to obtain the individual "iso-perception" curves as functions of the mechanical work exerted. We found that the "iso-perception" curve corresponding to a "moderate" perception of effort may represent the individual "tolerance threshold" for prolonged lifting tasks, since physiological responses at this level of intensity did not change significantly and the respiratory exchange ratio was less than one. The individually tolerable weight for lifting tasks lasting 30 min has been expressed as a percentage of the isoinertial MLC value and compared with the currently recommended limits for prolonged lifting tasks (Italian legislation D.L. 626/94). On the basis of our preliminary results a "tolerance threshold" of 20% MLC has been proposed for prolonged lifting tasks.

Computational Analysis of Powered Lift Augmentation for the LEAPTech Distributed Electric Propulsion Wing

NASA Technical Reports Server (NTRS)

Deere, Karen A.; Viken, Sally A.; Carter, Melissa B.; Viken, Jeffrey K.; Wiese, Michael R.; Farr, Norma L.

2017-01-01

A computational study of a distributed electric propulsion wing with a 40deg flap deflection has been completed using FUN3D. Two lift-augmentation power conditions were compared with the power-off configuration on the high-lift wing (40deg flap) at a 73 mph freestream flow and for a range of angles of attack from -5 degrees to 14 degrees. The computational study also included investigating the benefit of corotating versus counter-rotating propeller spin direction to powered-lift performance. The results indicate a large benefit in lift coefficient, over the entire range of angle of attack studied, by using corotating propellers that all spin counter to the wingtip vortex. For the landing condition, 73 mph, the unpowered 40deg flap configuration achieved a maximum lift coefficient of 2.3. With high-lift blowing the maximum lift coefficient increased to 5.61. Therefore, the lift augmentation is a factor of 2.4. Taking advantage of the fullspan lift augmentation at similar performance means that a wing powered with the distributed electric propulsion system requires only 42 percent of the wing area of the unpowered wing. This technology will allow wings to be 'cruise optimized', meaning that they will be able to fly closer to maximum lift over drag conditions at the design cruise speed of the aircraft.

Occupational lifting and pelvic pain during pregnancy: a study within the Danish National Birth Cohort.

PubMed

Larsen, Pernille Stemann; Strandberg-Larsen, Katrine; Juhl, Mette; Svendsen, Susanne Wulff; Bonde, Jens Peter; Andersen, Anne-Marie Nybo

2013-01-01

Pelvic pain during pregnancy is a common ailment, and the disease is a major cause of sickness absence during pregnancy. It is plausible that occupational lifting may be a risk factor of pelvic pain during pregnancy, but no previous studies have examined this specific exposure. The aim of this study was to examine the association between occupational lifting and pelvic pain during pregnancy. The study comprised 50 143 pregnant women, enrolled in the Danish National Birth Cohort in the period from 1996-2002. During pregnancy, the women provided information on occupational lifting (weight load and daily frequency), and six months post partum on pelvic pain. Adjusted odds ratios for pelvic pain during pregnancy according to occupational lifting were calculated by logistic regression. Any self-reported occupational lifting (>1 time/day and loads weighing >10 kg) was associated with an increased risk of pelvic pain during pregnancy as compared to no such lifting. A confounder-adjusted exposure-response relation was observed between self-reported total loads lifted and pelvic pain during pregnancy. Daily lifting of both medium (11-20 kg) and heavy loads (>20 kg) were associated with increased risk, and the highest risk was observed among women who lifted heavy loads independent of exposure to medium loads. Occupational lifting may increase the risk of pelvic pain during pregnancy.

76 FR 26606 - Drawbridge Operation Regulation; Illinois Waterway, Near Morris, IL

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-09

... allow removal of the existing lift span and installation of the replacement lift span. This deviation...-navigation position for eighty-four hours while the existing lift span is removed and the replacement lift...

76 FR 40237 - Drawbridge Operation Regulation; Illinois Waterway, Near Morris, IL

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-08

... allow removal of the existing lift span and installation of the replacement lift span. This deviation... position for eighty-four hours while the existing lift span is removed and the replacement lift span is...

Effect of camber on the trimmed lift capability of a close-coupled canard-wing configuration. [test in the Langley high speed 7- by 10-foot tunnel

NASA Technical Reports Server (NTRS)

Gloss, B. B.

1978-01-01

A close-coupled canard-wing configuration was tested in the Langely high-speed 7 by 10 foot tunnel at a Mach number of 0.30 to determine the effect of changing wing camber on the trimmed lift capability. Trimmed lift coefficients of near 2.0 were attained; however, the data indicated that the highest buffet-free trimmed lift coefficient attainable was approximately 1.30. The buffet used in this investigation were qualitative in nature and gave no indication of buffet intensity. Thus, the trimmed lift coefficient of near 2.0 might be attainable if the buffet intensity was not too high. The data showed that there was approximately a 10 percent variation in drag coefficient, for different model configurations, at a given trimmed lift coefficient. Large increases in wing lift had only small effects on canard lift.

Two years' outcome of thread lifting with absorbable barbed PDO threads: Innovative score for objective and subjective assessment.

PubMed

Ali, Yasser Helmy

2018-02-01

Thread-lifting rejuvenation procedures have evolved again, with the development of absorbable threads. Although they have gained popularity among plastic surgeons and dermatologists, very few articles have been written in literature about absorbable threads. This study aims to evaluate two years' outcome of thread lifting using absorbable barbed threads for facial rejuvenation. Prospective comparative stud both objectively and subjectively and follow-up assessment for 24 months. Thread lifting for face rejuvenation has significant long-lasting effects that include skin lifting from 3-10 mm and high degree of patients' satisfaction with less incidence rate of complications, about 4.8%. Augmented results are obtained when thread lifting is combined with other lifting and rejuvenation modalities. Significant facial rejuvenation is achieved by thread lifting and highly augmented results are observed when they are combined with Botox, fillers, and/or platelet rich plasma (PRP) rejuvenations.

Effects of height and load weight on shoulder muscle work during overhead lifting task.

PubMed

Blache, Y; Desmoulins, L; Allard, P; Plamondon, A; Begon, M

2015-01-01

Few musculoskeletal models are available to assess shoulder deeper muscle demand during overhead lifting tasks. Our objective was to implement a musculoskeletal model to assess the effect of lifting height and load on shoulder muscle work. A musculoskeletal model scaled from 15 male subjects was used to calculate shoulder muscle work during six lifting tasks. Boxes containing three different loads (6, 12 and 18 kg) were lifted by the subjects from the waist to shoulder or eye level. After optimisation of the maximal isometric force of the model's muscles, the bio-fidelity of the model was improved by 19%. The latter was able to reproduce the subjects' lifting movements. Mechanical work of the rotator cuff muscles, upper trapezius and anterior deltoid was increased with lifting load and height augmentation. In conclusion, the use of a musculoskeletal model validated by electromyography enabled to evaluate the muscle demand of deep muscles during lifting tasks.

Using verbal instructions to influence lifting mechanics - Does the directive "lift with your legs, not your back" attenuate spinal flexion?

PubMed

Beach, Tyson A C; Stankovic, Tatjana; Carnegie, Danielle R; Micay, Rachel; Frost, David M

2018-02-01

"Use your legs" is commonly perceived as sound advice to prevent lifting-related low-back pain and injuries, but there is limited evidence that this directive attenuates the concomitant biomechanical risk factors. Body segment kinematic data were collected from 12 men and 12 women who performed a laboratory lifting/lowering task after being provided with different verbal instructions. The main finding was that instructing participants to lift "without rounding your lower back" had a greater effect on the amount of spine flexion they exhibited when lifting/lowering than instructing them to lift "with your legs instead of your back" and "bend your knees and hips". It was concluded that if using verbal instructions to discourage spine flexion when lifting, the instructions should be spine- rather than leg-focused. Copyright © 2017 Elsevier Ltd. All rights reserved.

Method for calculating lift distributions for unswept wings with flaps or ailerons by use of nonlinear section lift data

NASA Technical Reports Server (NTRS)

Sivells, James C; Westrick, Gertrude C

1952-01-01

A method is presented which allows the use of nonlinear section lift data in the calculation of the spanwise lift distribution of unswept wings with flaps or ailerons. This method is based upon lifting line theory and is an extension to the method described in NACA rep. 865. The mathematical treatment of the discontinuity in absolute angle of attack at the end of the flap or aileron involves the use of a correction factor which accounts for the inability of a limited trigonometric series to represent adequately the spanwise lift distribution. A treatment of the apparent discontinuity in maximum section lift coefficient is also described. Simplified computing forms containing detailed examples are given for both symmetrical and asymmetrical lift distributions. A few comparisons of calculated characteristics with those obtained experimentally are also presented.

Lift enhancement by bats' dynamically changing wingspan

PubMed Central

Wang, Shizhao; Zhang, Xing; He, Guowei; Liu, Tianshu

2015-01-01

This paper elucidates the aerodynamic role of the dynamically changing wingspan in bat flight. Based on direct numerical simulations of the flow over a slow-flying bat, it is found that the dynamically changing wingspan can significantly enhance the lift. Further, an analysis of flow structures and lift decomposition reveal that the elevated vortex lift associated with the leading-edge vortices intensified by the dynamically changing wingspan considerably contributed to enhancement of the time-averaged lift. The nonlinear interaction between the dynamically changing wing and the vortical structures plays an important role in the lift enhancement of a flying bat in addition to the geometrical effect of changing the lifting-surface area in a flapping cycle. In addition, the dynamically changing wingspan leads to the higher efficiency in terms of generating lift for a given amount of the mechanical energy consumed in flight. PMID:26701882

Optimum oil production planning using infeasibility driven evolutionary algorithm.

PubMed

Singh, Hemant Kumar; Ray, Tapabrata; Sarker, Ruhul

2013-01-01

In this paper, we discuss a practical oil production planning optimization problem. For oil wells with insufficient reservoir pressure, gas is usually injected to artificially lift oil, a practice commonly referred to as enhanced oil recovery (EOR). The total gas that can be used for oil extraction is constrained by daily availability limits. The oil extracted from each well is known to be a nonlinear function of the gas injected into the well and varies between wells. The problem is to identify the optimal amount of gas that needs to be injected into each well to maximize the amount of oil extracted subject to the constraint on the total daily gas availability. The problem has long been of practical interest to all major oil exploration companies as it has the potential to derive large financial benefit. In this paper, an infeasibility driven evolutionary algorithm is used to solve a 56 well reservoir problem which demonstrates its efficiency in solving constrained optimization problems. Furthermore, a multi-objective formulation of the problem is posed and solved using a number of algorithms, which eliminates the need for solving the (single objective) problem on a regular basis. Lastly, a modified single objective formulation of the problem is also proposed, which aims to maximize the profit instead of the quantity of oil. It is shown that even with a lesser amount of oil extracted, more economic benefits can be achieved through the modified formulation.

Self-actuating grapple automatically engages and releases loads from overhead cranes

NASA Technical Reports Server (NTRS)

Froehlich, J. A.; Karastas, G. A.

1966-01-01

Two-piece grapple mechanism consisting of a lift knob secured to the load and a grapple member connected to the crane or lift automatically disengages the load from the overhead lifting device when the load contacts the ground. The key feature is the sliding collar under the lift knob which enables the grapple latch to be stripped off over the lift knob.

49 CFR 571.404 - Standard No. 404; Platform lift installations in motor vehicles.

Code of Federal Regulations, 2013 CFR

2013-10-01

... vehicle, with the vehicle's HVAC system turned off, for a minimum of 20 minutes, after which the engine is... Motor Vehicle Safety Standard No. 403, Lift Systems for Motor Vehicles (49 CFR 571.403). S4.1.2Lift... Safety Standard No. 403, Lift Systems for Motor Vehicles (49 CFR 571.403). S4.1.3Platform lifts must be...

49 CFR 571.404 - Standard No. 404; Platform lift installations in motor vehicles.

Code of Federal Regulations, 2014 CFR

2014-10-01

... vehicle, with the vehicle's HVAC system turned off, for a minimum of 20 minutes, after which the engine is... Motor Vehicle Safety Standard No. 403, Lift Systems for Motor Vehicles (49 CFR 571.403). S4.1.2Lift... Safety Standard No. 403, Lift Systems for Motor Vehicles (49 CFR 571.403). S4.1.3Platform lifts must be...

49 CFR 571.404 - Standard No. 404; Platform lift installations in motor vehicles.

Code of Federal Regulations, 2012 CFR

2012-10-01

... vehicle, with the vehicle's HVAC system turned off, for a minimum of 20 minutes, after which the engine is... Motor Vehicle Safety Standard No. 403, Lift Systems for Motor Vehicles (49 CFR 571.403). S4.1.2Lift... Safety Standard No. 403, Lift Systems for Motor Vehicles (49 CFR 571.403). S4.1.3Platform lifts must be...

Cold-forceps avulsion with adjuvant snare-tip soft coagulation (CAST) is an effective and safe strategy for the management of non-lifting large laterally spreading colonic lesions.

PubMed

Tate, David J; Bahin, Farzan F; Desomer, Lobke; Sidhu, Mayenaaz; Gupta, Vikas; Bourke, Michael J

2018-01-01

 Non-lifting large laterally spreading colorectal lesions (LSLs) are challenging to resect endoscopically and often necessitate surgery. A safe, simple technique to treat non-lifting LSLs endoscopically with robust long-term outcomes has not been described.  In this single-center prospective observational study of consecutive patients referred for endoscopic mucosal resection (EMR) of LSLs ≥ 20 mm, LSLs not completely resectable by snare because of non-lifting underwent standardized completion of resection with cold-forceps avulsion and adjuvant snare-tip soft coagulation (CAST). Scheduled surveillance colonoscopies were performed at 4 - 6 months (SC1) and 18 months (SC2). Primary outcomes were endoscopic evidence of adenoma clearance and avoidance of surgery. The secondary outcome was safety.  From January 2012 to October 2016, 540 lifting LSLs (82.2 %) underwent complete snare excision at EMR. CAST was required for complete removal in 101 non-lifting LSLs (17.8 %): 63 naïve non-lifting lesions (NNLs; 62.7 %) and 38 previously attempted non-lifting lesions (PANLs; 37.3 %). PANLs were smaller ( P  < 0.001) and more likely to be non-granular ( P  = 0.001) than the lifting LSLs. NNLs were of similar size ( P  = 0.77) and morphology ( P  = 0.10) to the lifting LSLs. CAST was successful in all cases and adverse events were comparable to lifting LSLs resected by complete snare excision. Recurrence at SC1 was comparable for PANLs (15.2 %) and lifting LSLs (15.3 %; P  = 0.99), whereas NNLs recurred more frequently (27.5 %; P  = 0.049); however, surgery was no more common for either type of non-lifting LSL than for lifting LSLs.  CAST is a safe, effective, and surgery-sparing therapy for the majority of non-lifting LSLs. It is easy to use, inexpensive, and does not require additional equipment. © Georg Thieme Verlag KG Stuttgart · New York.

AFC-Enabled Simplified High-Lift System Integration Study

NASA Technical Reports Server (NTRS)

Hartwich, Peter M.; Dickey, Eric D.; Sclafani, Anthony J.; Camacho, Peter; Gonzales, Antonio B.; Lawson, Edward L.; Mairs, Ron Y.; Shmilovich, Arvin

2014-01-01

The primary objective of this trade study report is to explore the potential of using Active Flow Control (AFC) for achieving lighter and mechanically simpler high-lift systems for transonic commercial transport aircraft. This assessment was conducted in four steps. First, based on the Common Research Model (CRM) outer mold line (OML) definition, two high-lift concepts were developed. One concept, representative of current production-type commercial transonic transports, features leading edge slats and slotted trailing edge flaps with Fowler motion. The other CRM-based design relies on drooped leading edges and simply hinged trailing edge flaps for high-lift generation. The relative high-lift performance of these two high-lift CRM variants is established using Computational Fluid Dynamics (CFD) solutions to the Reynolds-Averaged Navier-Stokes (RANS) equations for steady flow. These CFD assessments identify the high-lift performance that needs to be recovered through AFC to have the CRM variant with the lighter and mechanically simpler high-lift system match the performance of the conventional high-lift system. Conceptual design integration studies for the AFC-enhanced high-lift systems were conducted with a NASA Environmentally Responsible Aircraft (ERA) reference configuration, the so-called ERA-0003 concept. These design trades identify AFC performance targets that need to be met to produce economically feasible ERA-0003-like concepts with lighter and mechanically simpler high-lift designs that match the performance of conventional high-lift systems. Finally, technical challenges are identified associated with the application of AFC-enabled highlift systems to modern transonic commercial transports for future technology maturation efforts.

Estimation of unsteady lift on a pitching airfoil from wake velocity surveys

NASA Technical Reports Server (NTRS)

Zaman, K. B. M. Q.; Panda, J.; Rumsey, C. L.

1993-01-01

The results of a joint experimental and computational study on the flowfield over a periodically pitched NACA0012 airfoil, and the resultant lift variation, are reported in this paper. The lift variation over a cycle of oscillation, and hence the lift hysteresis loop, is estimated from the velocity distribution in the wake measured or computed for successive phases of the cycle. Experimentally, the estimated lift hysteresis loops are compared with available data from the literature as well as with limited force balance measurements. Computationally, the estimated lift variations are compared with the corresponding variation obtained from the surface pressure distribution. Four analytical formulations for the lift estimation from wake surveys are considered and relative successes of the four are discussed.

Development of a Low-Lift Chiller Controller and Simplified Precooling Control Algorithm - Final Report

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

Gayeski, N.; Armstrong, Peter; Alvira, M.

2011-11-30

KGS Buildings LLC (KGS) and Pacific Northwest National Laboratory (PNNL) have developed a simplified control algorithm and prototype low-lift chiller controller suitable for model-predictive control in a demonstration project of low-lift cooling. Low-lift cooling is a highly efficient cooling strategy conceived to enable low or net-zero energy buildings. A low-lift cooling system consists of a high efficiency low-lift chiller, radiant cooling, thermal storage, and model-predictive control to pre-cool thermal storage overnight on an optimal cooling rate trajectory. We call the properly integrated and controlled combination of these elements a low-lift cooling system (LLCS). This document is the final report formore » that project.« less

Real-Time Radiographic In-Situ Characterization Of Ply Lift In Composite Aerospace Materials

NASA Technical Reports Server (NTRS)

Beshears, Ronald D.; Doering, Edward R.

2006-01-01

The problem of ply lifting in composite materials is a significant issue for various aerospace and military applications. A fundamental element in the prevention or mitigation of ply lift is determination of the timing of the ply lifting event during exposure of the composite material to flight conditions. The Marshall Space Flight Center s Nondestructive Evaluation Team developed a real-time radiographic technique for the detection of ply lift in carbon phenolic ablative materials in situ during live firings of subscale test motors in support of NASA s Reusable Solid Rocket Motor program, using amorphous silicon detector panels. The radiographic method has successfully detected ply lifting in seven consecutive carbon phenolic converging cones attached to solid fuel torches, providing the time of ply lift initiation in each test. Post-processing of the radiographic images improved the accuracy of timing measurements and allowed measurement of the ply lifting height as a function of time. Radiographic data correlated well with independent pressure and temperature measurements that indicate the onset of ply lift in the nozzle material.

Adaptive Practice: Next Generation Evidence-Based Practice in Digital Environments.

PubMed

Kennedy, Margaret Ann

2016-01-01

Evidence-based practice in nursing is considered foundational to safe, competent care. To date, rigid traditional perceptions of what constitutes 'evidence' have constrained the recognition and use of practice-based evidence and the exploitation of novel forms of evidence from data rich environments. Advancements such as the conceptualization of clinical intelligence, the prevalence of increasingly sophisticated digital health information systems, and the advancement of the Big Data phenomenon have converged to generate a new contemporary context. In today's dynamic data-rich environments, clinicians have new sources of valid evidence, and need a new paradigm supporting clinical practice that is adaptive to information generated by diverse electronic sources. This opinion paper presents adaptive practice as the next generation of evidence-based practice in contemporary evidence-rich environments and provides recommendations for the next phase of evolution.

Hand function is altered in individuals with a history of illicit stimulant use.

PubMed

Pearson-Dennett, Verity; Flavel, Stanley C; Wilcox, Robert A; Thewlis, Dominic; Vogel, Adam P; White, Jason M; Todd, Gabrielle

2014-01-01

Use of illicit stimulant drugs such as methamphetamine, cocaine, and ecstasy are a significant worldwide problem. However, little is known about the effect of these drugs on movement. The aim of the current study was to investigate hand function in adults with a history of illicit stimulant use. We hypothesized that prior use of illicit stimulant drugs is associated with abnormal manipulation of objects. The study involved 22 subjects with a history of illicit stimulant use (aged 29±8 yrs; time since last use: 1.8±4.0 yrs) and two control groups comprising 27 non-drug users (aged 25±8 yrs) and 17 cannabis users with no history of stimulant use (aged 22±5 yrs). Each subject completed screening tests (neuropsychological assessment, medical history questionnaire, lifetime drug history questionnaire, and urine drug screen) prior to gripping and lifting a light-weight object with the dominant right hand. Horizontal grip force, vertical lift force, acceleration, and first dorsal interosseus electromyographic (EMG) activity were recorded during three trials. In trial one, peak grip force was significantly greater in the stimulant group (12.8±3.9 N) than in the control groups (non-drug: 10.3±4.6 N; cannabis: 9.4±2.9 N, P<0.022). However, peak grip force did not differ between groups in trials two and three. The results suggest that individuals with a history of stimulant use overestimate the grip force required to manipulate a novel object but, are able to adapt grip force in subsequent lifts. The results suggest that movement dysfunction may be an unrecognized consequence of illicit stimulant use.

Relationships between Mechanical Variables in the Traditional and Close-Grip Bench Press.

PubMed

Lockie, Robert G; Callaghan, Samuel J; Moreno, Matthew R; Risso, Fabrice G; Liu, Tricia M; Stage, Alyssa A; Birmingham-Babauta, Samantha A; Stokes, John J; Giuliano, Dominic V; Lazar, Adrina; Davis, DeShaun L; Orjalo, Ashley J

2017-12-01

The study aim was to determine relationships between mechanical variables in the one-repetition maximum (1RM) traditional bench press (TBP) and close-grip bench press (CGBP). Twenty resistance-trained men completed a TBP and CGBP 1RM. The TBP was performed with the preferred grip; the CGBP with a grip width of 95% biacromial distance. A linear position transducer measured: lift distance and duration; work; and peak and mean power, velocity, and force. Paired samples t-tests (p < 0.05) compared the 1RM and mechanical variables for the TBP and CGBP; effect sizes (d) were also calculated. Pearson's correlations (r; p < 0.05) computed relationships between the TBP and CGBP. 1RM, lift duration, and mean force were greater in the TBP (d = 0.30-3.20). Peak power and velocity was greater for the CGBP (d = 0.50-1.29). The 1RM TBP correlated with CGBP 1RM, power, and force (r = 0.685-0.982). TBP work correlated with CGBP 1RM, lift distance, power, force, and work (r = 0.542-0.931). TBP power correlated with CGBP 1RM, power, force, velocity, and work (r = 0.484-0.704). TBP peak and mean force related to CGBP 1RM, power, and force (r = 0.596-0.980). Due to relationships between the load, work, power, and force for the TBP and CGBP, the CGBP could provide similar strength adaptations to the TBP with long-term use. The velocity profile for the CGBP was different to that of the TBP. The CGBP could be used specifically to improve high-velocity, upper-body pushing movements.

Hand Function is Altered in Individuals with a History of Illicit Stimulant Use

PubMed Central

Pearson-Dennett, Verity; Flavel, Stanley C.; Wilcox, Robert A.; Thewlis, Dominic; Vogel, Adam P.; White, Jason M.; Todd, Gabrielle

2014-01-01

Use of illicit stimulant drugs such as methamphetamine, cocaine, and ecstasy are a significant worldwide problem. However, little is known about the effect of these drugs on movement. The aim of the current study was to investigate hand function in adults with a history of illicit stimulant use. We hypothesized that prior use of illicit stimulant drugs is associated with abnormal manipulation of objects. The study involved 22 subjects with a history of illicit stimulant use (aged 29±8 yrs; time since last use: 1.8±4.0 yrs) and two control groups comprising 27 non-drug users (aged 25±8 yrs) and 17 cannabis users with no history of stimulant use (aged 22±5 yrs). Each subject completed screening tests (neuropsychological assessment, medical history questionnaire, lifetime drug history questionnaire, and urine drug screen) prior to gripping and lifting a light-weight object with the dominant right hand. Horizontal grip force, vertical lift force, acceleration, and first dorsal interosseus electromyographic (EMG) activity were recorded during three trials. In trial one, peak grip force was significantly greater in the stimulant group (12.8±3.9 N) than in the control groups (non-drug: 10.3±4.6 N; cannabis: 9.4±2.9 N, P<0.022). However, peak grip force did not differ between groups in trials two and three. The results suggest that individuals with a history of stimulant use overestimate the grip force required to manipulate a novel object but, are able to adapt grip force in subsequent lifts. The results suggest that movement dysfunction may be an unrecognized consequence of illicit stimulant use. PMID:25545892

Relationships between Mechanical Variables in the Traditional and Close-Grip Bench Press

PubMed Central

Callaghan, Samuel J.; Moreno, Matthew R.; Risso, Fabrice G.; Liu, Tricia M.; Stage, Alyssa A.; Birmingham-Babauta, Samantha A.; Stokes, John J.; Giuliano, Dominic V.; Lazar, Adrina; Davis, DeShaun L.; Orjalo, Ashley J.

2017-01-01

Abstract The study aim was to determine relationships between mechanical variables in the one-repetition maximum (1RM) traditional bench press (TBP) and close-grip bench press (CGBP). Twenty resistance-trained men completed a TBP and CGBP 1RM. The TBP was performed with the preferred grip; the CGBP with a grip width of 95% biacromial distance. A linear position transducer measured: lift distance and duration; work; and peak and mean power, velocity, and force. Paired samples t-tests (p < 0.05) compared the 1RM and mechanical variables for the TBP and CGBP; effect sizes (d) were also calculated. Pearson’s correlations (r; p < 0.05) computed relationships between the TBP and CGBP. 1RM, lift duration, and mean force were greater in the TBP (d = 0.30-3.20). Peak power and velocity was greater for the CGBP (d = 0.50-1.29). The 1RM TBP correlated with CGBP 1RM, power, and force (r = 0.685-0.982). TBP work correlated with CGBP 1RM, lift distance, power, force, and work (r = 0.542-0.931). TBP power correlated with CGBP 1RM, power, force, velocity, and work (r = 0.484-0.704). TBP peak and mean force related to CGBP 1RM, power, and force (r = 0.596-0.980). Due to relationships between the load, work, power, and force for the TBP and CGBP, the CGBP could provide similar strength adaptations to the TBP with long-term use. The velocity profile for the CGBP was different to that of the TBP. The CGBP could be used specifically to improve high-velocity, upper-body pushing movements. PMID:29339982

Effect of resistance training on muscle use during exercise

NASA Technical Reports Server (NTRS)

Ploutz, Lori L.; Tesch, Per A.; Biro, Ronald L.; Dudley, Gary A.

1994-01-01

This study examined the effect of resistance training on exercise-induced contrast shift in magnetic resonance (MR) images. It was hypothesized that a given load could be lifted after training with less muscle showing contrast shift, thereby suggesting less muscle was used to perform the exercise. Nine males trained the left quadriceps femoris (QF) muscle 2 days/wk for 9 wk using 3-6 sets of 12 knee extensions each day. The right QF served as a control. Exercise-induced contrast shifts in MR images evoked by each of three bouts of exercise (5 sets of 10 knee extensions with a load equal to 50, 75, and 100% of the maximum pretraining load that could be lifted for 5 sets of 10 repetitions) were quantified pre- and posttraining. MR image contrast shift was quantified by determining QF cross-sectional area (CSA) showing increased spin-spin relaxation time. One repetition maximum increased 14% in the left trained QF and 7% in the right untrained QF. Left QF CSA increased 5%, with no change in right QSF CSA. Left QF CSA showing contrast shift was less after each bout of the exercise test posttraining. This was also true, to a lesser extent, for the right QF at the higher two loads. The results suggest that short-term resistance training reduces MR image contrast shift evoked by a given effort, thereby reflecting the use of less muscle to lift the load. Because this response was evident in both trained and contralateral untrained muscle, neural factors are suggested to be responsible. The consequence of this adaptation could be to increase 'stress' per unit area of active muscle during the course of training and thereby evoke hypertrophy.

Lipid Microarray Biosensor for Biotoxin Detection.

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

Singh, Anup K.; Throckmorton, Daniel J.; Moran-Mirabal, Jose C.

2006-05-01

We present the use of micron-sized lipid domains, patterned onto planar substrates and within microfluidic channels, to assay the binding of bacterial toxins via total internal reflection fluorescence microscopy (TIRFM). The lipid domains were patterned using a polymer lift-off technique and consisted of ganglioside-populated DSPC:cholesterol supported lipid bilayers (SLBs). Lipid patterns were formed on the substrates by vesicle fusion followed by polymer lift-off, which revealed micron-sized SLBs containing either ganglioside GT1b or GM1. The ganglioside-populated SLB arrays were then exposed to either Cholera toxin subunit B (CTB) or Tetanus toxin fragment C (TTC). Binding was assayed on planar substrates bymore » TIRFM down to 1 nM concentration for CTB and 100 nM for TTC. Apparent binding constants extracted from three different models applied to the binding curves suggest that binding of a protein to a lipid-based receptor is strongly affected by the lipid composition of the SLB and by the substrate on which the bilayer is formed. Patterning of SLBs inside microfluidic channels also allowed the preparation of lipid domains with different compositions on a single device. Arrays within microfluidic channels were used to achieve segregation and selective binding from a binary mixture of the toxin fragments in one device. The binding and segregation within the microfluidic channels was assayed with epifluorescence as proof of concept. We propose that the method used for patterning the lipid microarrays on planar substrates and within microfluidic channels can be easily adapted to proteins or nucleic acids and can be used for biosensor applications and cell stimulation assays under different flow conditions. KEYWORDS. Microarray, ganglioside, polymer lift-off, cholera toxin, tetanus toxin, TIRFM, binding constant.4« less

Constraining Plasma Conditions of the IPT via Spectral Analysis of UV & Visible Emissions and Comparing with a Physical Chemistry Model

NASA Astrophysics Data System (ADS)

Nerney, E. G.; Bagenal, F.; Yoshioka, K.; Schmidt, C.

2017-12-01

Io emits volcanic gases into space at a rate of about a ton per second. The gases become ionized and trapped in Jupiter's strong magnetic field, forming a torus of plasma that emits 2 terawatts of UV emissions. In recent work re-analyzing UV emissions observed by Voyager, Galileo, & Cassini, we found plasma conditions consistent with a physical chemistry model with a neutral source of dissociated sulfur dioxide from Io (Nerney et al., 2017). In further analysis of UV observations from JAXA's Hisaki mission (using our spectral emission model) we constrain the torus composition with ground based observations. The physical chemistry model (adapted from Delamere et al., 2005) is then used to match derived plasma conditions. We correlate the oxygen to sulfur ratio of the neutral source with volcanic eruptions to understand the change in magnetospheric plasma conditions. Our goal is to better understand and constrain both the temporal and spatial variability of the flow of mass and energy from Io's volcanic atmosphere to Jupiter's dynamic magnetosphere.

An historical survey of computational methods in optimal control.

NASA Technical Reports Server (NTRS)

Polak, E.

1973-01-01

Review of some of the salient theoretical developments in the specific area of optimal control algorithms. The first algorithms for optimal control were aimed at unconstrained problems and were derived by using first- and second-variation methods of the calculus of variations. These methods have subsequently been recognized as gradient, Newton-Raphson, or Gauss-Newton methods in function space. A much more recent addition to the arsenal of unconstrained optimal control algorithms are several variations of conjugate-gradient methods. At first, constrained optimal control problems could only be solved by exterior penalty function methods. Later algorithms specifically designed for constrained problems have appeared. Among these are methods for solving the unconstrained linear quadratic regulator problem, as well as certain constrained minimum-time and minimum-energy problems. Differential-dynamic programming was developed from dynamic programming considerations. The conditional-gradient method, the gradient-projection method, and a couple of feasible directions methods were obtained as extensions or adaptations of related algorithms for finite-dimensional problems. Finally, the so-called epsilon-methods combine the Ritz method with penalty function techniques.

Uniform magnetic fields in density-functional theory

NASA Astrophysics Data System (ADS)

Tellgren, Erik I.; Laestadius, Andre; Helgaker, Trygve; Kvaal, Simen; Teale, Andrew M.

2018-01-01

We construct a density-functional formalism adapted to uniform external magnetic fields that is intermediate between conventional density functional theory and Current-Density Functional Theory (CDFT). In the intermediate theory, which we term linear vector potential-DFT (LDFT), the basic variables are the density, the canonical momentum, and the paramagnetic contribution to the magnetic moment. Both a constrained-search formulation and a convex formulation in terms of Legendre-Fenchel transformations are constructed. Many theoretical issues in CDFT find simplified analogs in LDFT. We prove results concerning N-representability, Hohenberg-Kohn-like mappings, existence of minimizers in the constrained-search expression, and a restricted analog to gauge invariance. The issue of additivity of the energy over non-interacting subsystems, which is qualitatively different in LDFT and CDFT, is also discussed.

Structural optimization: Status and promise

NASA Astrophysics Data System (ADS)

Kamat, Manohar P.

Chapters contained in this book include fundamental concepts of optimum design, mathematical programming methods for constrained optimization, function approximations, approximate reanalysis methods, dual mathematical programming methods for constrained optimization, a generalized optimality criteria method, and a tutorial and survey of multicriteria optimization in engineering. Also included are chapters on the compromise decision support problem and the adaptive linear programming algorithm, sensitivity analyses of discrete and distributed systems, the design sensitivity analysis of nonlinear structures, optimization by decomposition, mixed elements in shape sensitivity analysis of structures based on local criteria, and optimization of stiffened cylindrical shells subjected to destabilizing loads. Other chapters are on applications to fixed-wing aircraft and spacecraft, integrated optimum structural and control design, modeling concurrency in the design of composite structures, and tools for structural optimization. (No individual items are abstracted in this volume)

Uniform magnetic fields in density-functional theory.

PubMed

Tellgren, Erik I; Laestadius, Andre; Helgaker, Trygve; Kvaal, Simen; Teale, Andrew M

2018-01-14

We construct a density-functional formalism adapted to uniform external magnetic fields that is intermediate between conventional density functional theory and Current-Density Functional Theory (CDFT). In the intermediate theory, which we term linear vector potential-DFT (LDFT), the basic variables are the density, the canonical momentum, and the paramagnetic contribution to the magnetic moment. Both a constrained-search formulation and a convex formulation in terms of Legendre-Fenchel transformations are constructed. Many theoretical issues in CDFT find simplified analogs in LDFT. We prove results concerning N-representability, Hohenberg-Kohn-like mappings, existence of minimizers in the constrained-search expression, and a restricted analog to gauge invariance. The issue of additivity of the energy over non-interacting subsystems, which is qualitatively different in LDFT and CDFT, is also discussed.

Adaptive Highlighting of Links to Assist Surfing on the Internet

DTIC Science & Technology

2002-01-01

search engines do not offer a satisfactory solution, their indexing cycle is long and creates a time lag of about one month. Moreover, sometimes search engines offer a huge amount of documents, which is hard to constrain and to increase the ratio of relevant information. A novel AI-assisted surfing method, which highlights links during surfing is studied here. The method makes use

Experimental joint quantum measurements with minimum uncertainty.

PubMed

Ringbauer, Martin; Biggerstaff, Devon N; Broome, Matthew A; Fedrizzi, Alessandro; Branciard, Cyril; White, Andrew G

2014-01-17

Quantum physics constrains the accuracy of joint measurements of incompatible observables. Here we test tight measurement-uncertainty relations using single photons. We implement two independent, idealized uncertainty-estimation methods, the three-state method and the weak-measurement method, and adapt them to realistic experimental conditions. Exceptional quantum state fidelities of up to 0.999 98(6) allow us to verge upon the fundamental limits of measurement uncertainty.

KSC-2009-1893

NASA Image and Video Library

2009-02-26

CAPE CANAVERAL, Fla. – In high bay 4 of the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida, a large overhead crane lifts the Ares I-X service module, which will be mated to the service adapter in the bay. Ares I-X is the test flight for the Ares I. The I-X flight will provide NASA an early opportunity to test and prove hardware, facilities and ground operations associated with Ares I. The launch of the 327-foot-tall, full-scale Ares I-X, targeted for July 2009, will be the first in a series of unpiloted rocket launches from Kennedy. Photo credit: NASA/Tim Jacobs

KSC-2009-3119

NASA Image and Video Library

2009-05-11

CAPE CANAVERAL, Fla. – In high bay 4 of the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida, the framework known as the "birdcage" lifts the Ares I-X simulator crew module-launch abort system, or CM-LAS. The CM-LAS stack will be mated with the simulator service module-service adapter stack. Ares I-X is the flight test for the Ares I. The I-X flight will provide NASA an early opportunity to test and prove hardware, facilities and ground operations associated with Ares I. The launch of the 327-foot-tall, full-scale Ares I-X is targeted for August 2009. Photo credit: NASA/Kim Shiflett

KSC-2009-1892

NASA Image and Video Library

2009-02-26

CAPE CANAVERAL, Fla. – In high bay 4 of the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida, workers attach a large overhead crane to the Ares I-X service module, on the floor. The module will be lifted and mated to the service adapter. Ares I-X is the test flight for the Ares I. The I-X flight will provide NASA an early opportunity to test and prove hardware, facilities and ground operations associated with Ares I. The launch of the 327-foot-tall, full-scale Ares I-X, targeted for July 2009, will be the first in a series of unpiloted rocket launches from Kennedy. Photo credit: NASA/Tim Jacobs

Human exploration of space and power development

NASA Technical Reports Server (NTRS)

Cohen, Aaron

1991-01-01

Reasons for mounting the Space Exploration Initiative, the variables facing U.S. planners, and the developmental technologies that will be needed to support this initiative are discussed. The three more advanced technological approaches in the field of power generation described include a lunar-based solar power system, a geosynchronous-based earth orbit solar power satellite system, and the utilization of helium-3/deuterium fusion reaction to create a nuclear fuel cycle. It is noted that the major elements of the SEI will include a heavy-lift launch vehicle, a transfer vehicle and a descent/ascent vehicle for use on lunar missions and adaptable to Mars exploration.

Lifting the Markov blankets of socio-cultural evolution. A comment on "Answering Schrödinger's question: A free-energy formulation" by Maxwell James Désormeau Ramstead et al.

NASA Astrophysics Data System (ADS)

Leydesdorff, Loet

2018-03-01

Ramstead et al. [8] claim an encompassing ontology which can be used as a heuristics for studying life, mind, and society both empirically and in terms of computer simulations. The systems levels are self-organizing into a hierarchy; "Markov blankets" close the various levels for one another. Homo sapiens sapiens is placed at the top of this hierarchy as "the world's most complex living systems." Humans are said to generate "(epi)genetically-specified expectations that have been shaped by selection to guide action-perception cycles toward adaptive or unsurprising states."

The Z1 truss is lifted up the RSS on Launch Pad 39A

NASA Technical Reports Server (NTRS)

2000-01-01

With its umbilical hoses stretched out, the payload canister (left) with the Integrated Truss Structure Z1 inside nears the top of the passage to the Payload Changeout Room. There the Z1 truss will be removed and later transferred to Space Shuttle Discovery's payload bay. The Z1 truss is the first of 10 that will become the backbone of the International Space Station, eventually stretching the length of a football field. Along with its companion payload, the third Pressurized Mating Adapter, the Z1 is scheduled to be launched aboard Discovery Oct. 5 at 9:38 p.m. EDT.

KSC-97PC1108

NASA Image and Video Library

1997-07-22

Flight mechanics from NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif., work on the lifting fixture that picks up the Cassini spacecraft in KSC’s Payload Hazardous Servicing Facility. The orbiter alone weighs about 4,750 pounds (2,150 kilograms). At launch, the combined orbiter, Huygens probe, launch vehicle adapter, and propellants will weigh about 12,346 pounds (5,600 kilograms). Scheduled for launch in October, the Cassini mission, a joint US-European four-year orbital surveillance of Saturn's atmosphere and magnetosphere, its rings, and its moons, seeks insight into the origins and evolution of the early solar system. JPL is managing the Cassini project for NASA

[Geriatric medicine].

PubMed

Lajoso, Sonia; Launay, Cyrille P; Poloni, Barbara; Büla, Christophe; Gold, Gabriel; Lang, Pierre-Olivier

2017-01-11

In 2016, consequences, contributing factors, and prevention of inappropriate drug prescribing were investigated. Two studies lift the veil on unexplained falls and syncope. A meta-analysis questions the need to adapting transfusion's threshold to comorbidities, and another one the performance of screening for swallowing disorders. The Framingham Heart Study reports the declining of the incidence of vascular dementia. The role played by microbleeds in cognitive deterioration was investigated and aducanumab showed encouraging effect in Alzheimer's disease. When vaccination against influenza for health workers in nursing home was challenged by a meta-analysis this recommendation must be followed. Vaccines against shingles are effective and safe, and a study confirms the efficacy of the HZ7su among 70+.

View of West end of central lift span truss web ...

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

View of West end of central lift span truss web of Tensaw River Bridge, showing web brace of lift girder superstructure, looking west - Tensaw River Lift Bridge, Spanning Tensaw River at U.S. Highway 90, Mobile, Mobile County, AL

Lifting Safety: Tips To Help Prevent Back Injuries

MedlinePlus

... injury from lifting? How can I improve my environment to reduce my risk of back injuries? Resources National Safety Council, Lift and Carry U.S. Department of Labor: Occupational Safety and Health Administration, Heavy Lifting Last Updated: March 15, 2017 ...

Inexpensive Dramatic Pneumatic Lift

NASA Astrophysics Data System (ADS)

Morse, Robert A.

2017-09-01

Various experiments and demonstrations relate air pressure and air pressure difference to force and area. Carpenter and Minnix describe a large-scale pneumatic lift in which a person sitting on a board atop a plastic garbage bag is lifted when the bag is connected to the exhaustport of a vacuum cleaner, which easily lifts the person. This article describes the construction and use of an inexpensive hand-held pneumatic lift to demonstrate the same principle.

Variable pitch fan system for NASA/Navy research and technology aircraft

NASA Technical Reports Server (NTRS)

Ryan, W. P.; Black, D. M.; Yates, A. F.

1977-01-01

Preliminary design of a shaft driven, variable-pitch lift fan and lift-cruise fan was conducted for a V/STOL Research and Technology Aircraft. The lift fan and lift-cruise fan employed a common rotor of 157.5 cm diameter, 1.18 pressure ratio variable-pitch fan designed to operate at a rotor-tip speed of 284 mps. Fan performance maps were prepared and detailed aerodynamic characteristics were established. Cost/weight/risk trade studies were conducted for the blade and fan case. Structural sizing was conducted for major components and weights determined for both the lift and lift-cruise fans.

Investigation at Mach Numbers of 0.20 to 3.50 of Blended Wing-Body Combinations of Sonic Design with Diamond, Delta, and Arrow Plan Forms

NASA Technical Reports Server (NTRS)

Holdaway, George H.; Mellenthin, Jack A.

1960-01-01

The models had aspect-ratio-2 diamond, delta, and arrow wings with the leading edges swept 45.00 deg, 59.04 deg, and 70.82 deg, respectively. The wing sections were computed by varying the section shape along with the body radii (blending process) to match the prescribed area distribution and wing plan form. The wing sections had an average value of maximum thickness ratio of about 4 percent of the local chords in a streamwise direction. The models were tested with transition fixed at Reynolds numbers of about 4,000,000 to 9,000,0000, based on the mean aerodynamic chord of the wings. The effect of varying Reynolds number was checked at both subsonic and supersonic speeds. The diamond model was superior to the other plan forms at transonic speeds ((L/D)max = 11.00 to 9.52) because of its higher lift-curve slope and near optimum wave drag due to the blending process. For the wing thickness tested with the diamond model, the marked body and wing contouring required for transonic conditions resulted in a large wave-drag penalty at the higher supersonic Mach numbers where the leading and trailing edges of the wing were supersonic. Because of the low sweep of the trailing edge of the delta model, this configuration was less adaptable to the blending process. Removing a body bump prescribed by the Mach number 1.00 design resulted in a good supersonic design. This delta model with 10 percent less volume was superior to the other plan forms at Mach numbers of 1.55 to 2.35 ((L/D)max = 8.65 to 7.24), but it and the arrow model were equally good at Mach numbers of 2.50 to 3.50 ((L/D)max - 6.85 to O.39). At transonic speeds the arrow model was inferior because of the reduced lift-curve slope associated with its increased sweep and also because of the wing base drag. The wing base-drag coefficients of the arrow model based on the wing planform area decreased from a peak value of 0.0029 at Mach number 1.55 to 0.0003 at Mach number 3.50. Linear supersonic theory was satisfactory for predicting the aerodynamic trends at Mach numbers from 1.55 to 3.50 of lift-curve slope, wave drag, drag due to lift, aerodynamic-center location, and maximum lift-drag ratios for each of the models.

A comparative analysis of lumbar spine mechanics during barbell- and crate-lifting: implications for occupational lifting task assessments.

PubMed

Zehr, Jackie D; Carnegie, Danielle R; Welsh, Timothy N; Beach, Tyson A C

2018-03-19

To compare the effects of object handled and handgrip used on lumbar spine motion and loading during occupational lifting task simulations. Eight male and eight female volunteers performed barbell and crate lifts with a pronated (barbell) and a neutral (crate) handgrip. The mass of barbells/crates lifted was identical across the objects and fixed at 11.6 and 9.3 kg for men and women, respectively. The initial heights of barbells/crates were individualized to mid-shank level. Body segment kinematics and foot-ground reaction kinetics were collected, and then input into an electromyography-assisted dynamic biomechanical model to quantify lumbar spine motion and loading. Lumbar compression and net lumbosacral moment magnitudes were 416 N and 17 Nm lower when lifting a barbell than when lifting a crate (p < 0.001), respectively. There were no between-condition differences in lumbar flexion displacements (p > 0.392) or flexion/extension velocities (p > 0.085). Crate- and barbell-lifting tasks can be used interchangeably if assessing lifting mechanics based on peak spine motion variables. If assessments are based on the spine loading responses to task demands, however, then crate- and barbell-lifting tasks cannot be used interchangeably.

High-Lift Optimization Design Using Neural Networks on a Multi-Element Airfoil

NASA Technical Reports Server (NTRS)

Greenman, Roxana M.; Roth, Karlin R.; Smith, Charles A. (Technical Monitor)

1998-01-01

The high-lift performance of a multi-element airfoil was optimized by using neural-net predictions that were trained using a computational data set. The numerical data was generated using a two-dimensional, incompressible, Navier-Stokes algorithm with the Spalart-Allmaras turbulence model. Because it is difficult to predict maximum lift for high-lift systems, an empirically-based maximum lift criteria was used in this study to determine both the maximum lift and the angle at which it occurs. Multiple input, single output networks were trained using the NASA Ames variation of the Levenberg-Marquardt algorithm for each of the aerodynamic coefficients (lift, drag, and moment). The artificial neural networks were integrated with a gradient-based optimizer. Using independent numerical simulations and experimental data for this high-lift configuration, it was shown that this design process successfully optimized flap deflection, gap, overlap, and angle of attack to maximize lift. Once the neural networks were trained and integrated with the optimizer, minimal additional computer resources were required to perform optimization runs with different initial conditions and parameters. Applying the neural networks within the high-lift rigging optimization process reduced the amount of computational time and resources by 83% compared with traditional gradient-based optimization procedures for multiple optimization runs.

A fundamental study of drag and an assessment of conventional drag-due-to-lift reduction devices

NASA Astrophysics Data System (ADS)

Yates, J. E.; Donald, C. D.

1986-09-01

The integral conservation laws of fluid mechanics are used to assess the drag efficiency of lifting wings, both CTOL and various out-of-plane configurations. The drag-due-to-lift is separated into two major components: (1) the induced drag-due-to-lift that depends on aspect ratio but is relatively independent of Reynolds number; (2) the form drag-due-to-lift that is independent of aspect ratio but dependent on the details of the wing section design, planform and Reynolds number. For each lifting configuration there is an optimal load distribution that yields the minimum value of drag-due-to-lift. For well designed high aspect ratio CTOL wings the two drag components are independent. With modern design technology CTOL wings can be (and usually are) designed with a drag-due-to-lift efficiency close to unity. Wing tip-devices (winglets, feathers, sails, etc.) can improve drag-due-to-lift efficiency by 10 to 15% if they are designed as an integral part of the wing. As add-on devices they can be detrimental. It is estimated that 25% improvements of wing drag-due-to-lift efficiency can be obtained with joined tip configurations and vertically separated lifting elements without considering additional benefits that might be realized by improved structural efficiency. It is strongly recommended that an integrated aerodynamic/structural approach be taken in the design of (or research on) future out-of-plane configurations.

Three-Dimensional Effects in Multi-Element High Lift Computations

NASA Technical Reports Server (NTRS)

Rumsey, Christopher L.; LeeReusch, Elizabeth M.; Watson, Ralph D.

2003-01-01

In an effort to discover the causes for disagreement between previous two-dimensional (2-D) computations and nominally 2-D experiment for flow over the three-element McDonnell Douglas 30P-30N airfoil configuration at high lift, a combined experimental/CFD investigation is described. The experiment explores several different side-wall boundary layer control venting patterns, documents venting mass flow rates, and looks at corner surface flow patterns. The experimental angle of attack at maximum lift is found to be sensitive to the side-wall venting pattern: a particular pattern increases the angle of attack at maximum lift by at least 2 deg. A significant amount of spanwise pressure variation is present at angles of attack near maximum lift. A CFD study using three-dimensional (3-D) structured-grid computations, which includes the modeling of side-wall venting, is employed to investigate 3-D effects on the flow. Side-wall suction strength is found to affect the angle at which maximum lift is predicted. Maximum lift in the CFD is shown to be limited by the growth of an off-body corner flow vortex and consequent increase in spanwise pressure variation and decrease in circulation. The 3-D computations with and without wall venting predict similar trends to experiment at low angles of attack, but either stall too early or else overpredict lift levels near maximum lift by as much as 5%. Unstructured-grid computations demonstrate that mounting brackets lower the lift levels near maximum lift conditions.

Two-Dimensional High-Lift Aerodynamic Optimization Using Neural Networks

NASA Technical Reports Server (NTRS)

Greenman, Roxana M.

1998-01-01

The high-lift performance of a multi-element airfoil was optimized by using neural-net predictions that were trained using a computational data set. The numerical data was generated using a two-dimensional, incompressible, Navier-Stokes algorithm with the Spalart-Allmaras turbulence model. Because it is difficult to predict maximum lift for high-lift systems, an empirically-based maximum lift criteria was used in this study to determine both the maximum lift and the angle at which it occurs. The 'pressure difference rule,' which states that the maximum lift condition corresponds to a certain pressure difference between the peak suction pressure and the pressure at the trailing edge of the element, was applied and verified with experimental observations for this configuration. Multiple input, single output networks were trained using the NASA Ames variation of the Levenberg-Marquardt algorithm for each of the aerodynamic coefficients (lift, drag and moment). The artificial neural networks were integrated with a gradient-based optimizer. Using independent numerical simulations and experimental data for this high-lift configuration, it was shown that this design process successfully optimized flap deflection, gap, overlap, and angle of attack to maximize lift. Once the neural nets were trained and integrated with the optimizer, minimal additional computer resources were required to perform optimization runs with different initial conditions and parameters. Applying the neural networks within the high-lift rigging optimization process reduced the amount of computational time and resources by 44% compared with traditional gradient-based optimization procedures for multiple optimization runs.

A fundamental study of drag and an assessment of conventional drag-due-to-lift reduction devices

NASA Technical Reports Server (NTRS)

Yates, J. E.; Donald, C. D.

1986-01-01

The integral conservation laws of fluid mechanics are used to assess the drag efficiency of lifting wings, both CTOL and various out-of-plane configurations. The drag-due-to-lift is separated into two major components: (1) the induced drag-due-to-lift that depends on aspect ratio but is relatively independent of Reynolds number; (2) the form drag-due-to-lift that is independent of aspect ratio but dependent on the details of the wing section design, planform and Reynolds number. For each lifting configuration there is an optimal load distribution that yields the minimum value of drag-due-to-lift. For well designed high aspect ratio CTOL wings the two drag components are independent. With modern design technology CTOL wings can be (and usually are) designed with a drag-due-to-lift efficiency close to unity. Wing tip-devices (winglets, feathers, sails, etc.) can improve drag-due-to-lift efficiency by 10 to 15% if they are designed as an integral part of the wing. As add-on devices they can be detrimental. It is estimated that 25% improvements of wing drag-due-to-lift efficiency can be obtained with joined tip configurations and vertically separated lifting elements without considering additional benefits that might be realized by improved structural efficiency. It is strongly recommended that an integrated aerodynamic/structural approach be taken in the design of (or research on) future out-of-plane configurations.

Installation of Existing Lift Systems for the Handicapped on Light Rail Vehicles

DOT National Transportation Integrated Search

1985-05-01

This report documents the results of a three-phase program to install an existing transit bus wheelchair lift system on a Boeing Light Rail Vehicle (LRV). Program activities included a review of lift requirements, evaluation of existing lift systems,...

Magnetic resonance image restoration via dictionary learning under spatially adaptive constraints.

PubMed

Wang, Shanshan; Xia, Yong; Dong, Pei; Feng, David Dagan; Luo, Jianhua; Huang, Qiu

2013-01-01

This paper proposes a spatially adaptive constrained dictionary learning (SAC-DL) algorithm for Rician noise removal in magnitude magnetic resonance (MR) images. This algorithm explores both the strength of dictionary learning to preserve image structures and the robustness of local variance estimation to remove signal-dependent Rician noise. The magnitude image is first separated into a number of partly overlapping image patches. The statistics of each patch are collected and analyzed to obtain a local noise variance. To better adapt to Rician noise, a correction factor is formulated with the local signal-to-noise ratio (SNR). Finally, the trained dictionary is used to denoise each image patch under spatially adaptive constraints. The proposed algorithm has been compared to the popular nonlocal means (NLM) filtering and unbiased NLM (UNLM) algorithm on simulated T1-weighted, T2-weighted and PD-weighted MR images. Our results suggest that the SAC-DL algorithm preserves more image structures while effectively removing the noise than NLM and it is also superior to UNLM at low noise levels.

Management of cryotherapy-ineligible women in a “screen-and-treat” cervical cancer prevention program targeting HIV-infected women in Zambia: Lessons from the field

PubMed Central

Pfaendler, Krista S.; Mwanahamuntu, Mulindi H.; Sahasrabuddhe, Vikrant V.; Mudenda, Victor; Stringer, Jeffrey S.A.; Parham, Groesbeck P.

2009-01-01

Objective We demonstrate the feasibility of implementing a referral and management system for cryotherapy-ineligible women in a “screen-and-treat” cervical cancer prevention program targeting HIV-infected women in Zambia. Methods We established criteria for patient referral, developed a training program for loop electrosurgical excision procedure (LEEP) providers, and adapted LEEP to a resource-constrained setting. Results We successfully trained 15 nurses to perform visual inspection with acetic acid (VIA) followed by immediate cryotherapy. Women with positive tests but ineligible for cryotherapy were referred for further evaluation. We trained four Zambian physicians to evaluate referrals, perform punch biopsy, LEEP, and manage intra-operative and post-operative complications. From January 2006 through October 2007, a total of 8823 women (41.5% HIV seropositive) were evaluated by nurses in outlying prevention clinics; of these, 1477 (16.7%) were referred for physician evaluation based on established criteria. Of the 875 (59.2% of 1147 referred) that presented for evaluation, 748 (8.4% of total screened) underwent histologic evaluation in the form of punch biopsy or LEEP. Complications associated with LEEP included anesthesia reaction (n=2) which spontaneously resolved, intra-operative (n=12) and post-operative (n=2) bleeding managed by local measures, and post-operative infection (n=12) managed with antibiotics. Conclusion With adaptations for a resource-constrained environment, we have demonstrated that performing LEEP is feasible and safe, with low rates of complications that can be managed locally. It is important to establish referral and management systems using LEEP-based excisional evaluation for women with cryotherapy-ineligible lesions in VIA-based “screen-and-treat” protocols nested within HIV-care programs in resource-constrained settings. PMID:18556050

Management of cryotherapy-ineligible women in a "screen-and-treat" cervical cancer prevention program targeting HIV-infected women in Zambia: lessons from the field.

PubMed

Pfaendler, Krista S; Mwanahamuntu, Mulindi H; Sahasrabuddhe, Vikrant V; Mudenda, Victor; Stringer, Jeffrey S A; Parham, Groesbeck P

2008-09-01

We demonstrate the feasibility of implementing a referral and management system for cryotherapy-ineligible women in a "screen-and-treat" cervical cancer prevention program targeting HIV-infected women in Zambia. We established criteria for patient referral, developed a training program for loop electrosurgical excision procedure (LEEP) providers, and adapted LEEP to a resource-constrained setting. We successfully trained 15 nurses to perform visual inspection with acetic acid (VIA) followed by immediate cryotherapy. Women with positive tests but ineligible for cryotherapy were referred for further evaluation. We trained four Zambian physicians to evaluate referrals, perform punch biopsy, LEEP, and manage intra-operative and post-operative complications. From January 2006 through October 2007, a total of 8823 women (41.5% HIV seropositive) were evaluated by nurses in outlying prevention clinics; of these, 1477 (16.7%) were referred for physician evaluation based on established criteria. Of the 875 (59.2% of 1147 referred) that presented for evaluation, 748 (8.4% of total screened) underwent histologic evaluation in the form of punch biopsy or LEEP. Complications associated with LEEP included anesthesia reaction (n=2) which spontaneously resolved, intra-operative (n=12) and post-operative (n=2) bleeding managed by local measures, and post-operative infection (n=12) managed with antibiotics. With adaptations for a resource-constrained environment, we have demonstrated that performing LEEP is feasible and safe, with low rates of complications that can be managed locally. It is important to establish referral and management systems using LEEP-based excisional evaluation for women with cryotherapy-ineligible lesions in VIA-based "screen-and-treat" protocols nested within HIV-care programs in resource-constrained settings.

Approach Considerations in Aircraft with High-Lift Propeller Systems

NASA Technical Reports Server (NTRS)

Patterson, Michael D.; Borer, Nicholas K.

2017-01-01

NASA's research into distributed electric propulsion (DEP) includes the design and development of the X-57 Maxwell aircraft. This aircraft has two distinct types of DEP: wingtip propellers and high-lift propellers. This paper focuses on the unique opportunities and challenges that the high-lift propellers--i.e., the small diameter propellers distributed upstream of the wing leading edge to augment lift at low speeds--bring to the aircraft performance in approach conditions. Recent changes to the regulations related to certifying small aircraft (14 CFR x23) and these new regulations' implications on the certification of aircraft with high-lift propellers are discussed. Recommendations about control systems for high-lift propeller systems are made, and performance estimates for the X-57 aircraft with high-lift propellers operating are presented.

Understanding and applying principles of social cognition and ...

EPA Pesticide Factsheets

Environmental governance systems are under greater pressure to adapt and to cope with increased social and ecological uncertainty from stressors like climate change. We review principles of social cognition and decision making that shape and constrain how environmental governance systems adapt. We focus primarily on the interplay between key decision makers in society and legal systems. We argue that adaptive governance must overcome three cooperative dilemmas to facilitate adaptation: (1) encouraging collaborative problem solving, (2) garnering social acceptance and commitment, and (3) cultivating a culture of trust and tolerance for change and uncertainty. However, to do so governance systems must cope with biases in people’s decision making that cloud their judgment and create conflict. These systems must also satisfy people’s fundamental needs for self-determination, fairness, and security, ensuring that changes to environmental governance are perceived as legitimate, trustworthy, and acceptable. We discuss the implications of these principles for common governance solutions (e.g., public participation, enforcement) and conclude with methodological recommendations. We outline how scholars can investigate the social cognitive principles involved in cases of adaptive governance. Social-ecological stressors place significant pressure on major societal systems, triggering adaptive reforms in human governance and environmental law. Though potentially benefici

Demographic source-sink dynamics restrict local adaptation in Elliott's blueberry (Vaccinium elliottii).

PubMed

Anderson, Jill T; Geber, Monica A

2010-02-01

In heterogeneous landscapes, divergent selection can favor the evolution of locally adapted ecotypes, especially when interhabitat gene flow is minimal. However, if habitats differ in size or quality, source-sink dynamics can shape evolutionary trajectories. Upland and bottomland forests of the southeastern USA differ in water table depth, light availability, edaphic conditions, and plant community. We conducted a multiyear reciprocal transplant experiment to test whether Elliott's blueberry (Vaccinium elliottii) is locally adapted to these contrasting environments. Additionally, we exposed seedlings and cuttings to prolonged drought and flooding in the greenhouse to assess fitness responses to abiotic stress. Contrary to predictions of local adaptation, V. elliottii families exhibited significantly higher survivorship and growth in upland than in bottomland forests and under drought than flooded conditions, regardless of habitat of origin. Neutral population differentiation was minimal, suggesting widespread interhabitat migration. Population density, reproductive output, and genetic diversity were all significantly greater in uplands than in bottomlands. These disparities likely result in asymmetric gene flow from uplands to bottomlands. Thus, adaptation to a marginal habitat can be constrained by small populations, limited fitness, and immigration from a benign habitat. Our study highlights the importance of demography and genetic diversity in the evolution of local (mal)adaptation.

Chromosome inversions and ecological plasticity in the main African malaria mosquitoes

PubMed Central

Ayala, Diego; Acevedo, Pelayo; Pombi, Marco; Dia, Ibrahima; Boccolini, Daniela; Costantini, Carlo; Simard, Frédéric; Fontenille, Didier

2017-01-01

Chromosome inversions have fascinated the scientific community, mainly because of their role in the rapid adaption of different taxa to changing environments. However, the ecological traits linked to chromosome inversions have been poorly studied. Here, we investigated the roles played by 23 chromosome inversions in the adaptation of the four major African malaria mosquitoes to local environments in Africa. We studied their distribution patterns by using spatially explicit modeling and characterized the ecogeographical determinants of each inversion range. We then performed hierarchical clustering and constrained ordination analyses to assess the spatial and ecological similarities among inversions. Our results show that most inversions are environmentally structured, suggesting that they are actively involved in processes of local adaptation. Some inversions exhibited similar geographical patterns and ecological requirements among the four mosquito species, providing evidence for parallel evolution. Conversely, common inversion polymorphisms between sibling species displayed divergent ecological patterns, suggesting that they might have a different adaptive role in each species. These results are in agreement with the finding that chromosomal inversions play a role in Anopheles ecotypic adaptation. This study establishes a strong ecological basis for future genome-based analyses to elucidate the genetic mechanisms of local adaptation in these four mosquitoes. PMID:28071788

Epistatically Interacting Substitutions Are Enriched during Adaptive Protein Evolution

PubMed Central

Gong, Lizhi Ian; Bloom, Jesse D.

2014-01-01

Most experimental studies of epistasis in evolution have focused on adaptive changes—but adaptation accounts for only a portion of total evolutionary change. Are the patterns of epistasis during adaptation representative of evolution more broadly? We address this question by examining a pair of protein homologs, of which only one is subject to a well-defined pressure for adaptive change. Specifically, we compare the nucleoproteins from human and swine influenza. Human influenza is under continual selection to evade recognition by acquired immune memory, while swine influenza experiences less such selection due to the fact that pigs are less likely to be infected with influenza repeatedly in a lifetime. Mutations in some types of immune epitopes are therefore much more strongly adaptive to human than swine influenza—here we focus on epitopes targeted by human cytotoxic T lymphocytes. The nucleoproteins of human and swine influenza possess nearly identical numbers of such epitopes. However, mutations in these epitopes are fixed significantly more frequently in human than in swine influenza, presumably because these epitope mutations are adaptive only to human influenza. Experimentally, we find that epistatically constrained mutations are fixed only in the adaptively evolving human influenza lineage, where they occur at sites that are enriched in epitopes. Overall, our results demonstrate that epistatically interacting substitutions are enriched during adaptation, suggesting that the prevalence of epistasis is dependent on the underlying evolutionary forces at play. PMID:24811236

Wavelet-based adaptation methodology combined with finite difference WENO to solve ideal magnetohydrodynamics

NASA Astrophysics Data System (ADS)

Do, Seongju; Li, Haojun; Kang, Myungjoo

2017-06-01

In this paper, we present an accurate and efficient wavelet-based adaptive weighted essentially non-oscillatory (WENO) scheme for hydrodynamics and ideal magnetohydrodynamics (MHD) equations arising from the hyperbolic conservation systems. The proposed method works with the finite difference weighted essentially non-oscillatory (FD-WENO) method in space and the third order total variation diminishing (TVD) Runge-Kutta (RK) method in time. The philosophy of this work is to use the lifted interpolating wavelets as not only detector for singularities but also interpolator. Especially, flexible interpolations can be performed by an inverse wavelet transformation. When the divergence cleaning method introducing auxiliary scalar field ψ is applied to the base numerical schemes for imposing divergence-free condition to the magnetic field in a MHD equation, the approximations to derivatives of ψ require the neighboring points. Moreover, the fifth order WENO interpolation requires large stencil to reconstruct high order polynomial. In such cases, an efficient interpolation method is necessary. The adaptive spatial differentiation method is considered as well as the adaptation of grid resolutions. In order to avoid the heavy computation of FD-WENO, in the smooth regions fixed stencil approximation without computing the non-linear WENO weights is used, and the characteristic decomposition method is replaced by a component-wise approach. Numerical results demonstrate that with the adaptive method we are able to resolve the solutions that agree well with the solution of the corresponding fine grid.

Parametric Investigation of a High-Lift Airfoil at High Reynolds Numbers

NASA Technical Reports Server (NTRS)

Lin, John C.; Dominik, Chet J.

1997-01-01

A new two-dimensional, three-element, advanced high-lift research airfoil has been tested in the NASA Langley Research Center s Low-Turbulence Pressure Tunnel at a chord Reynolds number up to 1.6 x 107. The components of this high-lift airfoil have been designed using a incompressible computational code (INS2D). The design was to provide high maximum-lift values while maintaining attached flow on the single-segment flap at landing conditions. The performance of the new NASA research airfoil is compared to a similar reference high-lift airfoil. On the new high-lift airfoil the effects of Reynolds number on slat and flap rigging have been studied experimentally, as well as the Mach number effects. The performance trend of the high-lift design is comparable to that predicted by INS2D over much of the angle-of-attack range. However, the code did not accurately predict the airfoil performance or the configuration-based trends near maximum lift where the compressibility effect could play a major role.

Study of lifting operation of a tripod foundation for offshore wind turbine

NASA Astrophysics Data System (ADS)

Zhu, H.; Li, L.; Ong, M. C.

2017-12-01

This study addresses numerical analysis of the installation of a tripod foundation using a heavy lift vessel (HLV). Limiting sea states are firstly predicted in the frequency domain based on crane tip vertical motions using linear transfer functions. Then, numerical modelling and simulations are carried out in the time domain to analyse the coupled dynamic system taking into consideration of the nonlinearities of the system. In time-domain analysis, two lifting phases are brought into focus, i.e., the lift-off and the lowering phases. For the lift-off phase, two scenarios are considered, i.e., lift-off from the own deck of the HLV and lift-off from a transport barge. Moreover, comparative studies using two types of installation vessels, a floating vessel and a Jack-up, are investigated for the lowering process. Critical responses including the motions of the tripod and the lift wire tensions are presented and compared under various environmental and loading conditions.

Heat, mass and force flows in supersonic shockwave interaction

NASA Astrophysics Data System (ADS)

Dixon, John Michael

There is no cost effective way to deliver a payload to space and, with rising fuel prices, currently the price to travel commercially is also becoming more prohibitive to the public. During supersonic flight, compressive shock waves form around the craft which could be harnessed to deliver an additional lift on the craft. Using a series of hanging plates below a lifting wing design, the total lift generated can be increased above conventional values, while still maintaining a similar lift-to-drag ratio. Here, we study some of the flows involved in supersonic shockwave interaction. This analysis uses ANSYS Fluent Computational Fluid Dynamics package as the modeler. Our findings conclude an increase of up to 30% lift on the modeled craft while maintaining the lift-to-drag profile of the unmodified lifting wing. The increase in lift when utilizing the shockwave interaction could increase transport weight and reduce fuel cost for space and commercial flight, as well as mitigating negative effects associated with supersonic travel.

Lift-based up-ender and methods using same to manipulate a shipping container containing unirradiated nuclear fuel

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

Nilles, Michael J.

A shipping container containing an unirradiated nuclear fuel assembly is lifted off the ground by operating a crane to raise a lifting tool comprising a winch. The lifting tool is connected with the shipping container by a rigging line connecting with the shipping container at a lifting point located on the shipping container between the top and bottom of the shipping container, and by winch cabling connecting with the shipping container at the top of the shipping container. The shipping container is reoriented by operating the winch to adjust the length of the winch cabling so as to rotate themore » shipping container about the lifting point. Shortening the winch cabling rotates the shipping container about the lifting point from a horizontal orientation to a vertical orientation, while lengthening the winch cabling rotates the shipping container about the lifting point from the vertical orientation to the horizontal orientation.« less

EMG Processing Based Measures of Fatigue Assessment during Manual Lifting.

PubMed

Shair, E F; Ahmad, S A; Marhaban, M H; Mohd Tamrin, S B; Abdullah, A R

2017-01-01

Manual lifting is one of the common practices used in the industries to transport or move objects to a desired place. Nowadays, even though mechanized equipment is widely available, manual lifting is still considered as an essential way to perform material handling task. Improper lifting strategies may contribute to musculoskeletal disorders (MSDs), where overexertion contributes as the highest factor. To overcome this problem, electromyography (EMG) signal is used to monitor the workers' muscle condition and to find maximum lifting load, lifting height and number of repetitions that the workers are able to handle before experiencing fatigue to avoid overexertion. Past researchers have introduced several EMG processing techniques and different EMG features that represent fatigue indices in time, frequency, and time-frequency domain. The impact of EMG processing based measures in fatigue assessment during manual lifting are reviewed in this paper. It is believed that this paper will greatly benefit researchers who need a bird's eye view of the biosignal processing which are currently available, thus determining the best possible techniques for lifting applications.

Lifting bloody footwear impressions using alginate casts followed by chemical enhancement.

PubMed

Wiesner, Sarena; Izraeli, Elad; Shor, Yaron; Domb, Avi

2013-05-01

A method for lifting bloody footwear impressions using alginate casts and enhancing the lifted impressions with amido black is presented. On rough or dark substrates, background interferences may conceal significant details of footwear impressions. Illumination with alternative light sources and chemically enhancing the bloody footwear impressions may reveal additional details, but sometimes, lifting footwear impressions prior to enhancing is the only way to expose hidden details (by using blood reagents not adequate on the original). Several cast formulations were tested for lifting the footwear impressions. The best results were achieved using Aroma fine®. Enhancement of the footwear impressions was attempted with several reagents prior to lifting, during the casting process, and on the lifted footwear impressions. Applying amido black to footwear impressions lifted with alginate produced the sharpest and most detailed footwear impressions. Alginate castings followed by chemical enhancement with amido black may produce high-quality footwear impressions for comparison. © 2013 American Academy of Forensic Sciences.

Advanced metal lift-off process using electron-beam flood exposure of single-layer photoresist

NASA Astrophysics Data System (ADS)

Minter, Jason P.; Ross, Matthew F.; Livesay, William R.; Wong, Selmer S.; Narcy, Mark E.; Marlowe, Trey

1999-06-01

In the manufacture of many types of integrated circuit and thin film devices, it is desirable to use a lift-of process for the metallization step to avoid manufacturing problems encountered when creating metal interconnect structures using plasma etch. These problems include both metal adhesion and plasma etch difficulties. Key to the success of the lift-off process is the creation of a retrograde or undercut profile in the photoresists before the metal deposition step. Until now, lift-off processing has relied on costly multi-layer photoresists schemes, image reversal, and non-repeatable photoresist processes to obtain the desired lift-off profiles in patterned photoresist. This paper present a simple, repeatable process for creating robust, user-defined lift-off profiles in single layer photoresist using a non-thermal electron beam flood exposure. For this investigation, lift-off profiles created using electron beam flood exposure of many popular photoresists were evaluated. Results of lift-off profiles created in positive tone AZ7209 and ip3250 are presented here.

Wind tunnel and ground static investigation of a large scale model of a lift/cruise fan V/STOL aircraft

NASA Technical Reports Server (NTRS)

1976-01-01

An investigation was conducted in a 40 foot by 80 foot wind tunnel to determine the aerodynamic/propulsion characteristics of a large scale powered model of a lift/cruise fan V/STOL aircraft. The model was equipped with three 36 inch diameter turbotip X376B fans powered by three T58 gas generators. The lift fan was located forward of the cockpit area and the two lift/cruise fans were located on top of the wing adjacent to the fuselage. The three fans with associated thrust vectoring systems were used to provide vertical, and short, takeoff and landing capability. For conventional cruise mode operation, only the lift/cruise fans were utilized. The data that were obtained include lift, drag, longitudinal and lateral-directional stability characteristics, and control effectiveness. Data were obtained up to speeds of 120 knots at one model height of 20 feet for the conventional aerodynamic lift configuration and at several thrust vector angles for the powered lift configuration.

Does Simultaneous Liposuction Adversely Affect the Outcome of Thread Lifts? A Preliminary Result.

PubMed

Lee, Yong Woo; Park, Tae Hwan

2018-04-11

Along with advances in thread lift techniques and materials, ancillary procedures such as fat grafting, liposuction, or filler injections have been performed simultaneously. Some surgeons think that these ancillary procedures might affect the aesthetic outcomes of thread lifting possibly due to inadvertent injury to threads or loosening of soft tissue via passing the cannula in the surgical plane of the thread lifts. The purpose of the current study is to determine the effect of such ancillary procedures on the outcome of thread lifts in the human and cadaveric setting. We used human abdominal tissue after abdominoplasty and cadaveric faces. In the abdominal tissue, liposuction parallel to the parallel axis was performed in one area for 5 min. We counted 30 passes when liposuction was performed in one direction. This was repeated as we changed the direction of passages. The plane of thread lifts (dermal vs subcutaneous) and angle between liposuction and thread lifts (parallel vs perpendicular) were differentiated in this abdominal tissue study group. Then, we performed parallel or perpendicular thread lifts using a small slit incision. Using a tensiometer, the maximum holding strength was measured when pulling the thread out of the skin as much as possible. We also used faces of cadavers to prove whether the finding in human abdominal tissue is really valid with corresponding techniques. Our pilot study using abdominal tissue showed that liposuction after thread lifts adversely affects it regardless of the vector of thread lifts. In the cadaveric study, however, liposuction prior to thread lifting does not significantly affect the holding strength of thread lifts. Liposuction or fat grafting in the appropriate layer would not be a hurdle to safely performing simultaneous thread lifts if the target lift tissue is intra-SMAS or just above the SMAS layer. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Wind-Stress Dust Lifting in a Mars Global Circulation Model: Representation across Resolutions

NASA Astrophysics Data System (ADS)

Chapman, R.; Lewis, S.; Balme, M. R.; Steele, L.

2017-12-01

The formation of Martian dust storms is believed to be driven by dust lifting by near-surface wind stress (NSWS). Accurately representing this dust lifting within Mars Global Circulation Models (MGCMs) is important in order to gain a full understanding of the Martian dust storm cycle. Parameterisations of dust lifting by NSWS exist within several MGCMs; implementations differ but they all follow a similar design, so progress within one model is relevant to the entire field. Few studies have explored in detail how the results of these parameterisations can be affected by changing the horizontal resolution of the model. An accurate parameterisation of dust lifting by NSWS will lift a representative dust mass, reproducing characteristic dust optical depths in the atmosphere. The geographical distribution of the dust lifting by NSWS will also change throughout the year, affecting patterns of dust storm formation and development. Currently, suitable values for dust lifting parameters must be identified at every new model resolution. Resolutions of 5° latitude x 5° longitude are often used to model the Martian climate, as thermal tides and long-term weather patterns can be well represented at this resolution. However, smaller scale phenomena (such as near-surface winds driven by local topography) cannot be accurately depicted at this resolution. We use the LMD-UK MGCM to complete multi-year simulations across multiple model resolutions. Our experiments range from `low' resolution 5° lat x 5° lon to `high' resolution 1° lat x 1° lon. In experiments with fixed, constant lifting parameters, we find that higher resolution simulations lift more dust, but that this trend is asymptotic. At low resolutions, dust lifting increases proportionately with the increase in number of horizontal gridboxes. However, at high resolutions, doubling the number of gridboxes results only in a 30% increase in the total dust mass lifted. Geographical and temporal distributions of dust lifting are investigated, as well as the total dust lifted, in order to assess the optimum parameters for each resolution, and to develop a calibration scheme for this dust lifting across model resolutions. The scheme is verified through comparison with spacecraft observations of dust optical depths and dust storm locations.

Helicopter Toy and Lift Estimation

ERIC Educational Resources Information Center

Shakerin, Said

2013-01-01

A $1 plastic helicopter toy (called a Wacky Whirler) can be used to demonstrate lift. Students can make basic measurements of the toy, use reasonable assumptions and, with the lift formula, estimate the lift, and verify that it is sufficient to overcome the toy's weight. (Contains 1 figure.)

77 FR 38030 - Atlantic Highly Migratory Species; Lifting Trade Restrictive Measures

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-26

... of Atlantic Tunas (Commission). The proposed rule would lift the trade restrictions on importing... Commission adopted Recommendation 11-19, which requires Parties to lift import prohibitions on Atlantic... measures. As a result, the Commission adopted Recommendation 11-19, which requires Parties to lift import...