Sample records for stroke plane angle

  1. Hovering and targeting flight simulations of a dragonfly-like flapping wing-body model by the immersed boundary-lattice Boltzmann method

    NASA Astrophysics Data System (ADS)

    Hirohashi, Kensuke; Inamuro, Takaji

    2017-08-01

    Hovering and targeting flights of the dragonfly-like flapping wing-body model are numerically investigated by using the immersed boundary-lattice Boltzmann method. The governing parameters of the problem are the Reynolds number Re, the Froude number Fr, and the non-dimensional mass m. We set the parameters at Re = 200, Fr = 15 and m = 51. First, we simulate free flights of the model for various values of the phase difference angle ϕ between the forewing and the hindwing motions and for various values of the stroke angle β between the stroke plane and the horizontal plane. We find that the vertical motion of the model depends on the phase difference angle ϕ, and the horizontal motion of the model depends on the stroke angle β. Secondly, using the above results we try to simulate the hovering flight by dynamically changing the phase difference angle ϕ and the stroke angle β. The hovering flight can be successfully simulated by a simple proportional controller of the phase difference angle and the stroke angle. Finally, we simulate a targeting flight by dynamically changing the stroke angle β.

  2. Generation of the pitch moment during the controlled flight after takeoff of fruitflies.

    PubMed

    Chen, Mao Wei; Wu, Jiang Hao; Sun, Mao

    2017-01-01

    In the present paper, the controlled flight of fruitflies after voluntary takeoff is studied. Wing and body kinematics of the insects after takeoff are measured using high-speed video techniques, and the aerodynamic force and moment are calculated by the computational fluid dynamics method based on the measured data. How the control moments are generated is analyzed by correlating the computed moments with the wing kinematics. A fruit-fly has a large pitch-up angular velocity owing to the takeoff jump and the fly controls its body attitude by producing pitching moments. It is found that the pitching moment is produced by changes in both the aerodynamic force and the moment arm. The change in the aerodynamic force is mainly due to the change in angle of attack. The change in the moment arm is mainly due to the change in the mean stroke angle and deviation angle, and the deviation angle plays a more important role than the mean stroke angle in changing the moment arm (note that change in deviation angle implies variation in the position of the aerodynamic stroke plane with respect to the anatomical stroke plane). This is unlike the case of fruitflies correcting pitch perturbations in steady free flight, where they produce pitching moment mainly by changes in mean stroke angle.

  3. Compensatory Versus Noncompensatory Shoulder Movements Used for Reaching in Stroke.

    PubMed

    Levin, Mindy F; Liebermann, Dario G; Parmet, Yisrael; Berman, Sigal

    2016-08-01

    Background The extent to which the upper-limb flexor synergy constrains or compensates for arm motor impairment during reaching is controversial. This synergy can be quantified with a minimal marker set describing movements of the arm-plane. Objectives To determine whether and how (a) upper-limb flexor synergy in patients with chronic stroke contributes to reaching movements to different arm workspace locations and (b) reaching deficits can be characterized by arm-plane motion. Methods Sixteen post-stroke and 8 healthy control subjects made unrestrained reaching movements to targets located in ipsilateral, central, and contralateral arm workspaces. Arm-plane, arm, and trunk motion, and their temporal and spatial linkages were analyzed. Results Individuals with moderate/severe stroke used greater arm-plane movement and compensatory trunk movement compared to those with mild stroke and control subjects. Arm-plane and trunk movements were more temporally coupled in stroke compared with controls. Reaching accuracy was related to different segment and joint combinations for each target and group: arm-plane movement in controls and mild stroke subjects, and trunk and elbow movements in moderate/severe stroke subjects. Arm-plane movement increased with time since stroke and when combined with trunk rotation, discriminated between different subject groups for reaching the central and contralateral targets. Trunk movement and arm-plane angle during target reaches predicted the subject group. Conclusions The upper-limb flexor synergy was used adaptively for reaching accuracy by patients with mild, but not moderate/severe stroke. The flexor synergy, as parameterized by the amount of arm-plane motion, can be used by clinicians to identify levels of motor recovery in patients with stroke. © The Author(s) 2015.

  4. Wing motion measurement and aerodynamics of hovering true hoverflies.

    PubMed

    Mou, Xiao Lei; Liu, Yan Peng; Sun, Mao

    2011-09-01

    Most hovering insects flap their wings in a horizontal plane (body having a large angle from the horizontal), called `normal hovering'. But some of the best hoverers, e.g. true hoverflies, hover with an inclined stroke plane (body being approximately horizontal). In the present paper, wing and body kinematics of four freely hovering true hoverflies were measured using three-dimensional high-speed video. The measured wing kinematics was used in a Navier-Stokes solver to compute the aerodynamic forces of the insects. The stroke amplitude of the hoverflies was relatively small, ranging from 65 to 85 deg, compared with that of normal hovering. The angle of attack in the downstroke (∼50 deg) was much larger that in the upstroke (∼20 deg), unlike normal-hovering insects, whose downstroke and upstroke angles of attack are not very different. The major part of the weight-supporting force (approximately 86%) was produced in the downstroke and it was contributed by both the lift and the drag of the wing, unlike the normal-hovering case in which the weight-supporting force is approximately equally contributed by the two half-strokes and the lift principle is mainly used to produce the force. The mass-specific power was 38.59-46.3 and 27.5-35.4 W kg(-1) in the cases of 0 and 100% elastic energy storage, respectively. Comparisons with previously published results of a normal-hovering true hoverfly and with results obtained by artificially making the insects' stroke planes horizontal show that for the true hoverflies, the power requirement for inclined stroke-plane hover is only a little (<10%) larger than that of normal hovering.

  5. Wing and body kinematics of forward flight in drone-flies.

    PubMed

    Meng, Xue Guang; Sun, Mao

    2016-08-15

    Here, we present a detailed analysis of the wing and body kinematics in drone-flies in free flight over a range of speeds from hovering to about 8.5 m s(-1). The kinematics was measured by high-speed video techniques. As the speed increased, the body angle decreased and the stroke plane angle increased; the wingbeat frequency changed little; the stroke amplitude first decreased and then increased; the ratio of the downstroke duration to the upstroke duration increased; the mean positional angle increased at lower speeds but changed little at speeds above 3 m s(-1). At a speed above about 1.5 m s(-1), wing rotation at supination was delayed and that at pronation was advanced, and consequently the wing rotations were mostly performed in the upstroke. In the downstroke, the relative velocity of the wing increased and the effective angle of attack decreased with speed; in the upstroke, they both decreased with speed at lower speeds, and at higher speeds, the relative velocity became larger but the effective angle of attack became very small. As speed increased, the increasing inclination of the stroke plane ensured that the effective angle of attack in the upstroke would not become negative, and that the wing was in suitable orientations for vertical-force and thrust production.

  6. Hawkmoth flight performance in tornado-like whirlwind vortices.

    PubMed

    Ortega-Jimenez, Victor Manuel; Mittal, Rajat; Hedrick, Tyson L

    2014-06-01

    Vertical vortex systems such as tornadoes dramatically affect the flight control and stability of aircraft. However, the control implications of smaller scale vertically oriented vortex systems for small fliers such as animals or micro-air vehicles are unknown. Here we examined the flapping kinematics and body dynamics of hawkmoths performing hovering flights (controls) and maintaining position in three different whirlwind intensities with transverse horizontal velocities of 0.7, 0.9 and 1.2 m s(-1), respectively, generated in a vortex chamber. The average and standard deviation of yaw and pitch were respectively increased and reduced in comparison with hovering flights. Average roll orientation was unchanged in whirlwind flights but was more variable from wingbeat to wingbeat than in hovering. Flapping frequency remained unchanged. Wingbeat amplitude was lower and the average stroke plane angle was higher. Asymmetry was found in the angle of attack between right and left wings during both downstroke and upstroke at medium and high vortex intensities. Thus, hawkmoth flight control in tornado-like vortices is achieved by a suite of asymmetric and symmetric changes to wingbeat amplitude, stroke plane angle and principally angle of attack.

  7. Flow structures around a beetle in a tethered flight

    NASA Astrophysics Data System (ADS)

    Lee, Boogeon; Oh, Sehyeong; Park, Hyungmin; Choi, Haecheon

    2017-11-01

    In the present study, through a wind-tunnel experiment, we visualize the flow in a tethered flight of a rhinoceros beetle using a smoke-wire visualization technique. Measurements are done at five side planes along the wind span while varying the body angle (angle between the horizontal and the body axis) to investigate the influence of the stroke plane angle that was observed to change depending on the flight mode such as hovering, forward and takeoff flights so on. Observing that a large attached leading-edge vortex is only found on the hindwing, it is inferred that most of the aerodynamic forces would be generated by hindwings (flexible inner wings) compared to the elytra (hard outer wings). In addition, it is observed to use unsteady lift-generating mechanisms such as clap-and-fling, wing-wing interaction and wake capture. Finally, we discuss the relation between the advance ratio and Strouhal number by adjusting free-stream velocity and the body angle (i.e., angle of wake-induced flow). Supported by a Grant to Bio-Mimetic Robot Research Center Funded by Defense Acquisition Program Administration, and by ADD, Korea (UD130070ID).

  8. The Aerodynamics of Hovering Insect Flight. III. Kinematics

    NASA Astrophysics Data System (ADS)

    Ellington, C. P.

    1984-02-01

    Insects in free flight were filmed at 5000 frames per second to determine the motion of their wings and bodies. General comments are offered on flight behaviour and manoeuvrability. Changes in the tilt of the stroke plane with respect to the horizontal provides kinematic control of manoeuvres, analogous to the type of control used for helicopters. A projection analysis technique is described that solves for the orientation of the animal with respect to a camera-based coordinate system, giving full kinematic details for the longitudinal wing and body axes from single-view films. The technique can be applied to all types of flight where the wing motions are bilaterally symmetrical: forward, backward and hovering flight, as well as properly banked turns. An analysis of the errors of the technique is presented, and shows that the reconstructed angles for wing position should be accurate to within 1-2^circ in general. Although measurement of the angles of attack was not possible, visual estimations are given. Only 11 film sequences show flight velocities and accelerations that are small enough for the flight to be considered as `hovering'. Two sequences are presented for a hover-fly using an inclined stroke plane, and nine sequences of hovering with a horizontal stroke plane by another hover-fly, two crane-flies, a drone-fly, a ladybird beetle, a honey bee, and two bumble bees. In general, oscillations in the body position from its mean motion are within measurement error, about 1-2% of the wing length. The amplitudes of oscillation for the body angle are only a few degrees, but the phase relation of this oscillation to the wingbeat cycle could be determined for a few sequences. The phase indicates that the pitching moments governing the oscillations result from the wing lift at the ends of the wingbeat, and not from the wing drag or inertial forces. The mean pitching moment of the wings, which determines the mean body angle, is controlled by shifting the centre of lift over the cycle by changing the mean positional angle of the flapping wings. Deviations of the wing tip path from the stroke plane are never large, and no consistent pattern could be found for the wing paths of different insects; indeed, variations in the path were even observed for individual insects. The wing motion is not greatly different from simple harmonic motion, but does show a general trend towards higher accelerations and decelerations at either end of the wingbeat, with constant velocities during the middle of half-strokes. Root mean square and cube root mean cube angular velocities are on average about 4 and 9% lower than simple harmonic motion. Angles of attack are nearly constant during the middle of half-strokes, typically 35^circ at a position 70% along the wing length. The wing is twisted along its length, with angles of attack at the wing base some 10-20^circ greater than at the tip. The wings rotate through about 110^circ at either end of the wingbeat during 10-20% of the cycle period. The mean velocity of the wing edges during rotation is similar to the mean flapping velocity of the wing tip and greater than the flapping velocity for more proximal wing regions, which indicates that vortex shedding during rotation is comparable with that during flapping. The wings tend to rotate as a flat plate during the first half of rotation, which ends just before, or at, the end of the half-stroke. The hover-fly using an inclined stroke plane provides a notable exception to this general pattern: pronation is delayed and overlaps the beginning of the downstroke. The wing profile flexes along a more or less localized longitudinal axis during the second half of rotation, generating the `flip' profile postulated by Weis-Fogh for the hover-flies. This profile occurs to some extent for all of the insects, and is not exceptionally pronounced for the hover-fly. By the end of rotation the wings are nearly flat again, although a slight camber can sometimes be seen. Weis-Fogh showed that beneficial aerodynamic interference can result when the left and right wings come into contact during rotation at the end of the wingbeat. His `fling' mechanism creates the circulation required for wing lift on the subsequent half-stroke, and can be seen on my films of the Large Cabbage White butterfly, a plume moth, and the Mediterranean flour moth. However, their wings `peel' apart like two pieces of paper being separated, rather than fling open rigidly about the trailing edges. A `partial fling' was found for some insects, with the wings touching only along posterior wing areas. A `near fling' with the wings separated by a fraction of the chord was also observed for many insects. There is a continuous spectrum for the separation distance between the wings, in fact, and the separation can vary for a given insect during different manoeuvres. It is suggested that these variants on Weis-Fogh's fling mechanism also generate circulation for wing lift, although less effectively than a complete fling, and that changes in the separation distance may provide a fine control over the amount of lift produced.

  9. Ankle muscle coactivation and its relationship with ankle joint kinematics and kinetics during gait in hemiplegic patients after stroke.

    PubMed

    Kitatani, Ryosuke; Ohata, Koji; Sato, Shuhei; Watanabe, Aki; Hashiguchi, Yu; Yamakami, Natsuki; Sakuma, Kaoru; Yamada, Shigehito

    2016-06-01

    Increased ankle muscle coactivation during gait is a compensation strategy for enhancing postural stability in patients after stroke. However, no previous studies have demonstrated that increased ankle muscle coactivation influenced ankle joint movements during gait in patients after stroke. To investigate the relationship between ankle muscle coactivation and ankle joint movements in hemiplegic patients after stroke. Seventeen patients after stroke participated. The coactivation index (CoI) at the ankle joint was calculated separately for the first and second double support (DS1 and DS2, respectively) and single support (SS) phases on the paretic and non-paretic sides during gait using surface electromyography. Simultaneously, three-dimensional motion analysis was performed to measure the peak values of the ankle joint angle, moment, and power in the sagittal plane. Ground reaction forces (GRFs) of the anterior and posterior components and centers of pressure (COPs) trajectory ranges and velocities were also measured. The CoI during the SS phase on the paretic side was negatively related to ankle dorsiflexion angle, ankle plantarflexion moment, ankle joint power generation, and COP velocity on the paretic side. Furthermore, the CoI during the DS2 phase on both sides was negatively related to anterior GRF amplitude on each side. Increased ankle muscle coactivation is related to decreased ankle joint movement during the SS phase on the paretic side to enhance joint stiffness and compensate for stance limb instability, which may be useful for patients who have paretic instability during the stance phase after stroke.

  10. Three-dimensional kinematic analysis of upper and lower limb motion during gait of post-stroke patients

    PubMed Central

    Carmo, A.A.; Kleiner, A.F.R.; Lobo da Costa, P.H.; Barros, R.M.L.

    2012-01-01

    The aim of this study was to analyze the alterations of arm and leg movements of patients during stroke gait. Joint angles of upper and lower limbs and spatiotemporal variables were evaluated in two groups: hemiparetic group (HG, 14 hemiparetic men, 53 ± 10 years) and control group (CG, 7 able-bodied men, 50 ± 4 years). The statistical analysis was based on the following comparisons (P ≤ 0.05): 1) right versus left sides of CG; 2) affected (AF) versus unaffected (UF) sides of HG; 3) CG versus both the affected and unaffected sides of HG, and 4) an intracycle comparison of the kinematic continuous angular variables between HG and CG. This study showed that the affected upper limb motion in stroke gait was characterized by a decreased range of motion of the glenohumeral (HG: 6.3 ± 4.5, CG: 20.1 ± 8.2) and elbow joints (AF: 8.4 ± 4.4, UF: 15.6 ± 7.6) on the sagittal plane and elbow joint flexion throughout the cycle (AF: 68.2 ± 0.4, CG: 46.8 ± 2.7). The glenohumeral joint presented a higher abduction angle (AF: 14.2 ± 1.6, CG: 11.5 ± 4.0) and a lower external rotation throughout the cycle (AF: 4.6 ± 1.2, CG: 22.0 ± 3.0). The lower limbs showed typical alterations of the stroke gait patterns. Thus, the changes in upper and lower limb motion of stroke gait were identified. The description of upper limb motion in stroke gait is new and complements gait analysis. PMID:22473324

  11. Launch pad lightning protection effectiveness

    NASA Technical Reports Server (NTRS)

    Stahmann, James R.

    1991-01-01

    Using the striking distance theory that lightning leaders will strike the nearest grounded point on their last jump to earth corresponding to the striking distance, the probability of striking a point on a structure in the presence of other points can be estimated. The lightning strokes are divided into deciles having an average peak current and striking distance. The striking distances are used as radii from the points to generate windows of approach through which the leader must pass to reach a designated point. The projections of the windows on a horizontal plane as they are rotated through all possible angles of approach define an area that can be multiplied by the decile stroke density to arrive at the probability of strokes with the window average striking distance. The sum of all decile probabilities gives the cumulative probability for all strokes. The techniques can be applied to NASA-Kennedy launch pad structures to estimate the lightning protection effectiveness for the crane, gaseous oxygen vent arm, and other points. Streamers from sharp points on the structure provide protection for surfaces having large radii of curvature. The effects of nearby structures can also be estimated.

  12. Kinematics and wing shape across flight speed in the bat, Leptonycteris yerbabuenae

    PubMed Central

    Von Busse, Rhea; Hedenström, Anders; Winter, York; Johansson, L. Christoffer

    2012-01-01

    Summary The morphology and kinematics of a flying animal determines the resulting aerodynamic lift through the regulation of the speed of the air moving across the wing, the wing area and the lift coefficient. We studied the detailed three-dimensional wingbeat kinematics of the bat, Leptonycteris yerbabuenae, flying in a wind tunnel over a range of flight speeds (0–7 m/s), to determine how factors affecting the lift production vary across flight speed and within wingbeats. We found that the wing area, the angle of attack and the camber, which are determinants of the lift production, decreased with increasing speed. The camber is controlled by multiple mechanisms along the span, including the deflection of the leg relative to the body, the bending of the fifth digit, the deflection of the leading edge flap and the upward bending of the wing tip. All these measures vary throughout the wing beat suggesting active or aeroelastic control. The downstroke Strouhal number, Std, is kept relatively constant, suggesting that favorable flow characteristics are maintained during the downstroke, across the range of speeds studied. The Std is kept constant through changes in the stroke plane, from a strongly inclined stroke plane at low speeds to a more vertical stroke plane at high speeds. The mean angular velocity of the wing correlates with the aerodynamic performance and shows a minimum at the speed of maximum lift to drag ratio, suggesting a simple way to determine the optimal speed from kinematics alone. Taken together our results show the high degree of adjustments that the bats employ to fine tune the aerodynamics of the wings and the correlation between kinematics and aerodynamic performance. PMID:23259057

  13. Three-dimensional kinematics of the lower limbs during forward ice hockey skating.

    PubMed

    Upjohn, Tegan; Turcotte, René; Pearsall, David J; Loh, Jonathan

    2008-05-01

    The objectives of the study were to describe lower limb kinematics in three dimensions during the forward skating stride in hockey players and to contrast skating techniques between low- and high-calibre skaters. Participant motions were recorded with four synchronized digital video cameras while wearing reflective marker triads on the thighs, shanks, and skates. Participants skated on a specialized treadmill with a polyethylene slat bed at a self-selected speed for 1 min. Each participant completed three 1-min skating trials separated by 5 min of rest. Joint and limb segment angles were calculated within the local (anatomical) and global reference planes. Similar gross movement patterns and stride rates were observed; however, high-calibre participants showed a greater range and rate of joint motion in both the sagittal and frontal planes, contributing to greater stride length for high-calibre players. Furthermore, consequent postural differences led to greater lateral excursion during the power stroke in high-calibre skaters. In conclusion, specific kinematic differences in both joint and limb segment angle movement patterns were observed between low- and high-calibre skaters.

  14. Kinematic compensation for wing loss in flying damselflies.

    PubMed

    Kassner, Ziv; Dafni, Eyal; Ribak, Gal

    2016-02-01

    Flying insects can tolerate substantial wing wear before their ability to fly is entirely compromised. In order to keep flying with damaged wings, the entire flight apparatus needs to adjust its action to compensate for the reduced aerodynamic force and to balance the asymmetries in area and shape of the damaged wings. While several studies have shown that damaged wings change their flapping kinematics in response to partial loss of wing area, it is unclear how, in insects with four separate wings, the remaining three wings compensate for the loss of a fourth wing. We used high-speed video of flying blue-tailed damselflies (Ischnura elegans) to identify the wingbeat kinematics of the two wing pairs and compared it to the flapping kinematics after one of the hindwings was artificially removed. The insects remained capable of flying and precise maneuvering using only three wings. To compensate for the reduction in lift, they increased flapping frequency by 18±15.4% on average. To achieve steady straight flight, the remaining intact hindwing reduced its flapping amplitude while the forewings changed their stroke plane angle so that the forewing of the manipulated side flapped at a shallower stroke plane angle. In addition, the angular position of the stroke reversal points became asymmetrical. When the wingbeat amplitude and frequency of the three wings were used as input in a simple aerodynamic model, the estimation of total aerodynamic force was not significantly different (paired t-test, p=0.73) from the force produced by the four wings during normal flight. Thus, the removal of one wing resulted in adjustments of the motions of the remaining three wings, exemplifying the precision and plasticity of coordination between the operational wings. Such coordination is vital for precise maneuvering during normal flight but it also provides the means to maintain flight when some of the wings are severely damaged. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. A MEMS scanner with lateral and axial scanning capability for dual axes confocal endomicroscopic in-vivo imaging (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Li, Haijun; Li, Gaoming; Duan, Xiyu; Wang, Thomas D.

    2017-02-01

    Aimed to build a dual-axes confocal endomicroscope with an outer diameter of 5.5mm for in-vivo imaging applications, an electrostatic MEMS scanner has been developed to enable two dimensional (2D) light scanning in either horizontal plane or vertical cross-sectional plane. The device has a compact structure design to match the dual axes confocal architecture in the probe without blocking the collimated light beams of excitation and collection, and a cutting-free silicon-on-insulator(SOI) micromachining process is used for the fabrication. A novel lever-based gimbal-like mechanism is employed to enable three degrees of freedom motions for lateral and axial light scanning, and its geometry is optimized for achieving large deflection with high scanning speed. Based on parametric excitation, the device can work in resonant modes. Testing result shows that, up to +/-27° optical deflection angle for inner axis torsion motion with a frequency of 4.9kHz, up to +/-28.5° optical deflection angle for outer axis torsion motion with a frequency of 0.65kHz and 360μm stroke for out-of-plane translation motion with a frequency of 0.53kHz are achieved with <60V driving voltage. Based on these results, 2D imaging with frame rate of 5 10Hz and large field of view (1000μm x 1000μm in horizontal plane and 1000μm x 400μm in vertical plane) can be enabled by this scanner.

  16. The aerodynamic benefit of wing-wing interaction depends on stroke trajectory in flapping insect wings.

    PubMed

    Lehmann, Fritz-Olaf; Pick, Simon

    2007-04-01

    Flying insects may enhance their flight force production by contralateral wing interaction during dorsal stroke reversal ('clap-and-fling'). In this study, we explored the forces and moments due to clap-and-fling at various wing tip trajectories, employing a dynamically scaled electromechanical flapping device. The 17 tested bio-inspired kinematic patterns were identical in stroke amplitude, stroke frequency and angle of attack with respect to the horizontal stroke plane but varied in heaving motion. Clap-and-fling induced vertical force augmentation significantly decreased with increasing vertical force production averaged over the entire stroke cycle, whereas total force augmentation was independent from changes in force produced by a single wing. Vertical force augmentation was also largely independent of forces produced due to wing rotation at the stroke reversals, the sum of rotational circulation and wake capture force. We obtained maximum (17.4%) and minimum (1.4%) vertical force augmentation in two types of figure-eight stroke kinematics whereby rate and direction of heaving motion during fling may explain 58% of the variance in vertical force augmentation. This finding suggests that vertical wing motion distinctly alters the flow regime at the beginning of the downstroke. Using an analytical model, we determined pitching moments acting on an imaginary body of the flapping device from the measured time course of forces, the changes in length of the force vector's moment arm, the position of the centre of mass and body angle. The data show that pitching moments are largely independent from mean vertical force; however, clap-and-fling reinforces mean pitching moments by approximately 21%, compared to the moments produced by a single flapping wing. Pitching moments due to clap-and-fling significantly increase with increasing vertical force augmentation and produce nose-down moments in most of the tested patterns. The analytical model, however, shows that algebraic sign and magnitude of these moments may vary distinctly depending on both body angle and the distance between the wing hinge and the animal's centre of mass. Altogether, the data suggest that the benefit of clap-and-fling wing beat for vertical force enhancement and pitch balance may change with changing heaving motion and thus wing tip trajectory during manoeuvring flight. We hypothesize that these dependencies may have shaped the evolution of wing kinematics in insects that are limited by aerodynamic lift rather than by mechanical power of their flight musculature.

  17. Analysis of using the tongue deviation angle as a warning sign of a stroke

    PubMed Central

    2012-01-01

    Background The symptom of tongue deviation is observed in a stroke or transient ischemic attack. Nevertheless, there is much room for the interpretation of the tongue deviation test. The crucial factor is the lack of an effective quantification method of tongue deviation. If we can quantify the features of the tongue deviation and scientifically verify the relationship between the deviation angle and a stroke, the information provided by the tongue will be helpful in recognizing a warning of a stroke. Methods In this study, a quantification method of the tongue deviation angle was proposed for the first time to characterize stroke patients. We captured the tongue images of stroke patients (15 males and 10 females, ranging between 55 and 82 years of age); transient ischemic attack (TIA) patients (16 males and 9 females, ranging between 53 and 79 years of age); and normal subjects (14 males and 11 females, ranging between 52 and 80 years of age) to analyze whether the method is effective. In addition, we used the receiver operating characteristic curve (ROC) for the sensitivity analysis, and determined the threshold value of the tongue deviation angle for the warning sign of a stroke. Results The means and standard deviations of the tongue deviation angles of the stroke, TIA, and normal groups were: 6.9 ± 3.1, 4.9 ± 2.1 and 1.4 ± 0.8 degrees, respectively. Analyzed by the unpaired Student’s t-test, the p-value between the stroke group and the TIA group was 0.015 (>0.01), indicating no significant difference in the tongue deviation angle. The p-values between the stroke group and the normal group, as well as between the TIA group and the normal group were both less than 0.01. These results show the significant differences in the tongue deviation angle between the patient groups (stroke and TIA patients) and the normal group. These results also imply that the tongue deviation angle can effectively identify the patient group (stroke and TIA patients) and the normal group. With respect to the visual examination, 40% and 32% of stroke patients, 24% and 16% of TIA patients, and 4% and 0% of normal subjects were found to have tongue deviations when physicians “A” and “B” examined them. The variation showed the essentiality of the quantification method in a clinical setting. In the receiver operating characteristic curve (ROC), the Area Under Curve (AUC, = 0.96) indicates good discrimination. The tongue deviation angle more than the optimum threshold value (= 3.2°) predicts a risk of stroke. Conclusions In summary, we developed an effective quantification method to characterize the tongue deviation angle, and we confirmed the feasibility of recognizing the tongue deviation angle as an early warning sign of an impending stroke. PMID:22908956

  18. Analysis of using the tongue deviation angle as a warning sign of a stroke.

    PubMed

    Wei, Ching-Chuan; Huang, Shu-Wen; Hsu, Sheng-Lin; Chen, Hsing-Chung; Chen, Jong-Shin; Liang, Hsinying

    2012-08-21

    The symptom of tongue deviation is observed in a stroke or transient ischemic attack. Nevertheless, there is much room for the interpretation of the tongue deviation test. The crucial factor is the lack of an effective quantification method of tongue deviation. If we can quantify the features of the tongue deviation and scientifically verify the relationship between the deviation angle and a stroke, the information provided by the tongue will be helpful in recognizing a warning of a stroke. In this study, a quantification method of the tongue deviation angle was proposed for the first time to characterize stroke patients. We captured the tongue images of stroke patients (15 males and 10 females, ranging between 55 and 82 years of age); transient ischemic attack (TIA) patients (16 males and 9 females, ranging between 53 and 79 years of age); and normal subjects (14 males and 11 females, ranging between 52 and 80 years of age) to analyze whether the method is effective. In addition, we used the receiver operating characteristic curve (ROC) for the sensitivity analysis, and determined the threshold value of the tongue deviation angle for the warning sign of a stroke. The means and standard deviations of the tongue deviation angles of the stroke, TIA, and normal groups were: 6.9 ± 3.1, 4.9 ± 2.1 and 1.4 ± 0.8 degrees, respectively. Analyzed by the unpaired Student's t-test, the p-value between the stroke group and the TIA group was 0.015 (>0.01), indicating no significant difference in the tongue deviation angle. The p-values between the stroke group and the normal group, as well as between the TIA group and the normal group were both less than 0.01. These results show the significant differences in the tongue deviation angle between the patient groups (stroke and TIA patients) and the normal group. These results also imply that the tongue deviation angle can effectively identify the patient group (stroke and TIA patients) and the normal group. With respect to the visual examination, 40% and 32% of stroke patients, 24% and 16% of TIA patients, and 4% and 0% of normal subjects were found to have tongue deviations when physicians "A" and "B" examined them. The variation showed the essentiality of the quantification method in a clinical setting. In the receiver operating characteristic curve (ROC), the Area Under Curve (AUC, = 0.96) indicates good discrimination. The tongue deviation angle more than the optimum threshold value (= 3.2°) predicts a risk of stroke. In summary, we developed an effective quantification method to characterize the tongue deviation angle, and we confirmed the feasibility of recognizing the tongue deviation angle as an early warning sign of an impending stroke.

  19. Out-of-plane stretching for simultaneous generation of different morphological wrinkles on a soft matter

    NASA Astrophysics Data System (ADS)

    Li, Xin; Zhao, Zhi-Jun; Park, Sang-Hu

    2016-07-01

    This study demonstrates a simple and flexible out-of-plane induced mechanical stretching method for generating labyrinthic, waving, and straight orderly microscale directional wrinkles. Different complex wrinkling patterns were fabricated simultaneously using a UV-curable thin layer of resin NOA-68T that was coated on a soft foundation. Then an out-of-plane pre-straining deformation was applied by a specially designed punch to generate internal elastic instabilities. The surface wrinkling pattern characteristics (shapes and size) changed according to the amount of punch stroke (pre-strain) and the cross-sectional shape of the punch. This study confirms the usefulness of this method for controlling and generating local wrinkling patterns for diverse applications. As an example, the contact angles of a water droplet on a local area of the same pattern were measured to identify the change in wettability with respect to different wrinkling shapes. This method can be utilized in topographical tunable wrinkle fabrication for local surface modification.

  20. New digital measurement methods for left ventricular volume using real-time three-dimensional echocardiography: comparison with electromagnetic flow method and magnetic resonance imaging

    NASA Technical Reports Server (NTRS)

    Qin, J. J.; Jones, M.; Shiota, T.; Greenberg, N. L.; Firstenberg, M. S.; Tsujino, H.; Zetts, A. D.; Sun, J. P.; Cardon, L. A.; Odabashian, J. A.; hide

    2000-01-01

    AIM: The aim of this study was to investigate the feasibility and accuracy of using symmetrically rotated apical long axis planes for the determination of left ventricular (LV) volumes with real-time three-dimensional echocardiography (3DE). METHODS AND RESULTS: Real-time 3DE was performed in six sheep during 24 haemodynamic conditions with electromagnetic flow measurements (EM), and in 29 patients with magnetic resonance imaging measurements (MRI). LV volumes were calculated by Simpson's rule with five 3DE methods (i.e. apical biplane, four-plane, six-plane, nine-plane (in which the angle between each long axis plane was 90 degrees, 45 degrees, 30 degrees or 20 degrees, respectively) and standard short axis views (SAX)). Real-time 3DE correlated well with EM for LV stroke volumes in animals (r=0.68-0.95) and with MRI for absolute volumes in patients (r-values=0.93-0.98). However, agreement between MRI and apical nine-plane, six-plane, and SAX methods in patients was better than those with apical four-plane and bi-plane methods (mean difference = -15, -18, -13, vs. -31 and -48 ml for end-diastolic volume, respectively, P<0.05). CONCLUSION: Apically rotated measurement methods of real-time 3DE correlated well with reference standards for calculating LV volumes. Balancing accuracy and required time for these LV volume measurements, the apical six-plane method is recommended for clinical use.

  1. Planer orientation of the bilateral semicircular canals in dizzy patients.

    PubMed

    Aoki, Sachiko; Takei, Yasuhiko; Suzuki, Kazufumi; Masukawa, Ai; Arai, Yasuko

    2012-10-01

    Recent development of 3-dimensional analysis of eye movement enabled to detect the eye rotation axis, which is used to determine the responsible semicircular canal(s) in dizzy patients. Therefore, the knowledge of anatomical orientation of bilateral semicircular canals is essential, as all 6 canals influence the eye movements. Employing the new head coordinate system suitable for MR imaging, we calculated the angles of semicircular canal planes of both ears in 11 dizzy patients who had normal caloric response in both ears. The angles between adjacent canal pairs were nearly perpendicular in both ears. The angle between the posterior canal planes and head sagittal plane was 51° and significantly larger the angle between the anterior canal planes and head sagittal plane, which was 35°. The angle between the horizontal canal plane and head sagittal plane was almost orthogonal. Pairs of contralateral synergistic canal planes were not parallel, forming 10° between right and left horizontal canal planes, 17° between right anterior and left posterior canal planes and 19° between the right posterior and left anterior canal planes. Our measurement of the angles of adjacent canal pairs and the angle between each semicircular canal and head sagittal plane coincided with those of previous reports obtained from CT images and skull specimens. However, the angles between contralateral synergistic canal planes were more parallel than those of previous reports. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  2. A determination of occlusal plane comparing different levels of the tragus to form ala-tragal line or Camper's line: A photographic study.

    PubMed

    Kumar, Sandeep; Garg, Sandeep; Gupta, Seema

    2013-02-01

    The purpose of this study was to determine accurately the part of the tragus to be used to form the Ala-Tragal line or Camper's line in orthognathic profile patients. 150 dentate subjects with age of 18-40 years with orthognathic profile were sampled. Life-size lateral digital photographs of the face with fox plane were taken in natural head position. Different angles between Eye-Ear plane and occlusal plane (OT1-OP), Eye-Ear plane and ala-superior border of tragus (OT1-AT1), Eye-Ear plane and ala-middle border of tragus (OT1-AT2) and Eye-Ear plane and ala-inferior border of tragus (OT1-AT3) were calculated using computer software package, AutoCAD 2004. From the three angles formed by the Eye-ear plane (OT1 or FH plane) and the ala-tragal lines, the one closest to the angle formed between Eye-Ear plane (OT1) and occlusal plane (OP) was used to determine the occlusal plane of orientation. The obtained results were subjected to ANOVA F test, Tukey's Honestly significant difference test, followed by Karl Pearson coefficient of correlation test. P values of less than 0.05 were taken as statistically significant. The mean of base line angle i.e. OT1-OP angle (11.96 ± 4.36) was found to be close to OT1-AT2 angle (13.67 ± 1.93) and OT1-AT3 angle (10.31 ± 2.03), but OT1-OP angle was found to be more closer to OT1-AT3 angle. Comparison of mean angles showed that OT1-OP angle in both males (11.68) and females (12.51) is close to OT1-AT3 angle (males- 11.01, females- 11.95). The line joining from ala to the lower border of the tragus was parallel to the occlusal plane in 53.3% of the subjects. There was no influence of the sex on the level of occlusal plane.

  3. A determination of occlusal plane comparing different levels of the tragus to form ala-tragal line or Camper's line: A photographic study

    PubMed Central

    Garg, Sandeep; Gupta, Seema

    2013-01-01

    PURPOSE The purpose of this study was to determine accurately the part of the tragus to be used to form the Ala-Tragal line or Camper's line in orthognathic profile patients. MATERIALS AND METHODS 150 dentate subjects with age of 18-40 years with orthognathic profile were sampled. Life-size lateral digital photographs of the face with fox plane were taken in natural head position. Different angles between Eye-Ear plane and occlusal plane (OT1-OP), Eye-Ear plane and ala-superior border of tragus (OT1-AT1), Eye-Ear plane and ala-middle border of tragus (OT1-AT2) and Eye-Ear plane and ala-inferior border of tragus (OT1-AT3) were calculated using computer software package, AutoCAD 2004. From the three angles formed by the Eye-ear plane (OT1 or FH plane) and the ala-tragal lines, the one closest to the angle formed between Eye-Ear plane (OT1) and occlusal plane (OP) was used to determine the occlusal plane of orientation. The obtained results were subjected to ANOVA F test, Tukey's Honestly significant difference test, followed by Karl Pearson coefficient of correlation test. P values of less than 0.05 were taken as statistically significant. RESULTS The mean of base line angle i.e. OT1-OP angle (11.96 ± 4.36) was found to be close to OT1-AT2 angle (13.67 ± 1.93) and OT1-AT3 angle (10.31 ± 2.03), but OT1-OP angle was found to be more closer to OT1-AT3 angle. Comparison of mean angles showed that OT1-OP angle in both males (11.68) and females (12.51) is close to OT1-AT3 angle (males- 11.01, females- 11.95). CONCLUSION The line joining from ala to the lower border of the tragus was parallel to the occlusal plane in 53.3% of the subjects. There was no influence of the sex on the level of occlusal plane. PMID:23508203

  4. Numerical studies of the formation and destruction of vortices in a motored four-stroke piston-cylinder configuration

    NASA Technical Reports Server (NTRS)

    Schock, H. J.; Sosoka, D. J.; Ramos, J. I.

    1983-01-01

    A finite-difference procedure which solves the conservation equations of mass, momentum, and energy is used to investigate the effects of the compression ratio, engine speed, bore-to-stroke ratio, and air intake flow angle on the turbulent flow field within an axisymmetric piston-cylinder configuration. It is shown that in a four-stroke piston-cylinder configuration, the intake stroke is characterized by the formation of a piston vortex. The piston vortex is stretched during the intake stroke, and the head vortex has an almost constant diameter. For a 0-deg air intake flow angle, both vortices disappear by the end of the compression stroke; for an air intake flow angle of 45 deg, the flow field within the cylinder shows three elongated vortices which persist into the compression stroke and then break up and merge. It is also shown that larger bore-to-stroke ratios give rise to lower turbulent levels than smaller bore-to-stroke ratios and that the turbulent intensity is almost independent of the rpm.

  5. Effect of muscle length on strength and dexterity after stroke.

    PubMed

    Ada, L; Canning, C; Dwyer, T

    2000-02-01

    The effect of muscle length on strength and dexterity after stroke was investigated. The aim was to determine if poor function at a particular muscle length could be attributed solely to differential weakness at this joint angle or whether an additional problem of differential dexterity exists. This descriptive research study measured elbow flexor and extensor strength as well as dexterity at three elbow joint angles: 30 degrees , 60 degrees and 90 degrees flexion. Dexterity was measured independently of strength. Fifteen (seven female, eight male) chronic stroke patients (mean age 67 years) who could actively flex and extend their affected elbow participated. Ten neurologically normal control subjects (mean age 67 years) acted as controls. Strength was measured as peak elbow flexor and extensor torque at three angles; and dexterity was measured as coherence for slow and fast tracking also at three angles. Dexterity was not affected by muscle length but strength was and this finding was the same for both stroke and controls. While the magnitude of the torque-angle curves was not significantly different between stroke and controls, the shape of torque-angle curves was altered after stroke so that both the elbow flexors (p < 0.05) and extensors (p < 0.05) tested weaker in the testing position where they were shortest. Since there was no differential loss of dexterity, it appears that differential loss of strength, especially in the shortened range, may explain the clinical observation of poorer function at one muscle length than another after stroke. Specific training to strengthen the muscles in these ranges is therefore of clinical importance for rehabilitation.

  6. Kinematic control of aerodynamic forces on an inclined flapping wing with asymmetric strokes.

    PubMed

    Park, Hyungmin; Choi, Haecheon

    2012-03-01

    In the present study, we conduct an experiment using a one-paired dynamically scaled model of an insect wing, to investigate how asymmetric strokes with different wing kinematic parameters are used to control the aerodynamics of a dragonfly-like inclined flapping wing in still fluid. The kinematic parameters considered are the angles of attack during the mid-downstroke (α(md)) and mid-upstroke (α(mu)), and the duration (Δτ) and time of initiation (τ(p)) of the pitching rotation. The present dragonfly-like inclined flapping wing has the aerodynamic mechanism of unsteady force generation similar to those of other insect wings in a horizontal stroke plane, but the detailed effect of the wing kinematics on the force control is different due to the asymmetric use of the angle of attack during the up- and downstrokes. For example, high α(md) and low α(mu) produces larger vertical force with less aerodynamic power, and low α(md) and high α(mu) is recommended for horizontal force (thrust) production. The pitching rotation also affects the aerodynamics of a flapping wing, but its dynamic rotational effect is much weaker than the effect from the kinematic change in the angle of attack caused by the pitching rotation. Thus, the influences of the duration and timing of pitching rotation for the present inclined flapping wing are found to be very different from those for a horizontal flapping wing. That is, for the inclined flapping motion, the advanced and delayed rotations produce smaller vertical forces than the symmetric one and the effect of pitching duration is very small. On the other hand, for a specific range of pitching rotation timing, delayed rotation requires less aerodynamic power than the symmetric rotation. As for the horizontal force, delayed rotation with low α(md) and high α(mu) is recommended for long-duration flight owing to its high efficiency, and advanced rotation should be employed for hovering flight for nearly zero horizontal force. The present study suggests that manipulating the angle of attack during a flapping cycle is the most effective way to control the aerodynamic forces and corresponding power expenditure for a dragonfly-like inclined flapping wing.

  7. Unsteady aerodynamic force mechanisms of a hoverfly hovering with a short stroke-amplitude

    NASA Astrophysics Data System (ADS)

    Zhu, Hao Jie; Sun, Mao

    2017-08-01

    Hovering insects require a rather large lift coefficient. Many insects hover with a large stroke amplitude (120°-170°), and it has been found that the high lift is mainly produced by the delayed-stall mechanism. However, some insects hover with a small stroke amplitude (e.g., 65°). The delayed-stall mechanism might not work for these insects because the wings travel only a very short distance in a stroke, and other aerodynamic mechanisms must be operating. Here we explore the aerodynamic mechanisms of a hoverfly hovering with an inclined stroke plane and a small stroke amplitude (65.6°). The Navier-Stokes equations are numerically solved to give the flows and forces and the theory of vorticity dynamics used to reveal the aerodynamic mechanisms. The majority of the weight-supporting vertical force is produced in the mid portion of the downstroke, a short period (about 26% of the stroke cycle) in which the vertical force coefficient is larger than 4. The force is produced using a new mechanism, the "paddling mechanism." During the short period, the wing moves rapidly downward and forward at a large angle of attack (about 48°), and strong counter clockwise vorticity is produced continuously at the trailing edge and clockwise vorticity at the leading edge, resulting in a large time rate of change in the first moment of vorticity, hence the large aerodynamic force. It is interesting to note that with the well known delayed stall mechanism, the force is produced by the relative motion of two vortices of opposite sign, while in the "paddling mechanism," it is produced by generating new vortices of opposite sign at different locations.

  8. 14 CFR 25.1387 - Position light system dihedral angles.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first... two intersecting vertical planes, the first parallel to the longitudinal axis of the airplane, and the... axis. (d) Dihedral angle A (aft) is formed by two intersecting vertical planes making angles of 70...

  9. 14 CFR 27.1387 - Position light system dihedral angles.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first... two intersecting vertical planes, the first parallel to the longitudinal axis of the rotorcraft, and... longitudinal axis. (d) Dihedral angle A (aft) is formed by two intersecting vertical planes making angles of 70...

  10. Noninvasive Vascular Displacement Estimation for Relative Elastic Modulus Reconstruction in Transversal Imaging Planes

    PubMed Central

    Hansen, Hendrik H.G.; Richards, Michael S.; Doyley, Marvin M.; de Korte, Chris L.

    2013-01-01

    Atherosclerotic plaque rupture can initiate stroke or myocardial infarction. Lipid-rich plaques with thin fibrous caps have a higher risk to rupture than fibrotic plaques. Elastic moduli differ for lipid-rich and fibrous tissue and can be reconstructed using tissue displacements estimated from intravascular ultrasound radiofrequency (RF) data acquisitions. This study investigated if modulus reconstruction is possible for noninvasive RF acquisitions of vessels in transverse imaging planes using an iterative 2D cross-correlation based displacement estimation algorithm. Furthermore, since it is known that displacements can be improved by compounding of displacements estimated at various beam steering angles, we compared the performance of the modulus reconstruction with and without compounding. For the comparison, simulated and experimental RF data were generated of various vessel-mimicking phantoms. Reconstruction errors were less than 10%, which seems adequate for distinguishing lipid-rich from fibrous tissue. Compounding outperformed single-angle reconstruction: the interquartile range of the reconstructed moduli for the various homogeneous phantom layers was approximately two times smaller. Additionally, the estimated lateral displacements were a factor of 2–3 better matched to the displacements corresponding to the reconstructed modulus distribution. Thus, noninvasive elastic modulus reconstruction is possible for transverse vessel cross sections using this cross-correlation method and is more accurate with compounding. PMID:23478602

  11. Mechanical Characteristics of Reflex Durign Upright Posture in Paralyzed Subjects

    NASA Astrophysics Data System (ADS)

    Kim, Yongchul; Youm, Youngil; Lee, Bumsuk; Kim, Youngho; Choi, Hyeonki

    The characteristics of flexor reflexes have been investigated in the previous studies with human subjects who were seated or supine position. However, researchers did not describe how the spinal circuits are used in different hip angles for paralyzed subjects, such as the standing position with walker or cane. In upright posture the compatibility between a flexor reflex of leg and body balance is a special problem for lower limb injured subjects. Therefore, the purpose of this study was to investigate the effects of hip angle change on the flexor reflex evoked in standing paralyzed subjects supported by walker. In this study, six spinal cord injured and four stroke subjects were recruited through the inpatient physical therapy clinics of Korea national rehabilitation hospital. A single axis electronic goniometer was mounted on the lateral side of the hip joint of the impaired limb to record movements in the sagittal plane at this joint. The electronic goniometer was connected to a data acquisition system, through amplifiers to a computer. Since subject' posture influenced characteristics of the flexion reflex response, the subjects were supported in an upright posture by the help of parallelogram walder. Two series of tests were performed on each leg. The first series of the tests investigated the influence of hip angle during stationary standing posture on flexion reflex response. The hip angle was adjusted by the foot plate. The second examined the effect of the voluntary action of subject on swing motion during the gait. The electrically induced flexion reflex simultaneously produced the flexion of the hip, knee and dorsiflexion of the ankle enabling the swing phase of walking. Form the experimental results we observed that the reflex response of hip joint was largerwith the hip in the extended position than in the flexed position during standing posture. Under voluntary movement on flexion reflex during gaint, the peak hip angle induced by stimulation was increased in spinal cord injury and stroke patients by subject' voluntary movement.

  12. 14 CFR 29.1387 - Position light system dihedral angles.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... described in this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the... formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the rotorcraft... longitudinal axis. (d) Dihedral angle A (aft) is formed by two intersecting vertical planes making angles of 70...

  13. 14 CFR 23.1387 - Position light system dihedral angles.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... described in this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the... formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the airplane... longitudinal axis. (d) Dihedral angle A (aft) is formed by two intersecting vertical planes making angles of 70...

  14. Swallowing Kinematics and Factors Associated with Laryngeal Penetration and Aspiration in Stroke Survivors with Dysphagia.

    PubMed

    Seo, Han Gil; Oh, Byung-Mo; Han, Tai Ryoon

    2016-04-01

    The purpose of this study was to investigate swallowing kinematics and explore kinematic factors related with penetration-aspiration in patients with post-stroke dysphagia. Videofluoroscopic images of 68 patients with post-stroke dysphagia and 34 sex- and age-matched healthy controls swallowing a thin liquid were quantitatively analyzed using two-dimensional motion digitization. The measurements included the movement distances and velocities of the hyoid and larynx, and the maximal tilt angles and angular velocities of the epiglottis. All velocity variables were significantly decreased in the stroke patients compared to the controls. There was a significant difference in the maximal horizontal displacement of the larynx, but there were no significant differences in other displacements of the larynx, the maximal displacements of the hyoid bone, and the maximum tilt angle of the epiglottis between the two groups. The maximal tilt angle of the epiglottis was lower in the aspiration subgroup than in the no penetration/aspiration and penetration subgroups as well as the controls. The maximal tilt angle from the y axis showed a dichotomous pattern at 90° of the angle, and all 11 patients with an angle <90° showed either penetration or aspiration. In the ROC curve of the angle for prediction of aspiration, the area under the curve was 0.725 (95 % CI 0.557-0.892, P = 0.008). This study suggested that sluggish rather than decreased hyolaryngeal movements during swallowing are a remarkable feature of post-stroke dysphagia. The association of reduced epiglottic movement with the risk of aspiration in patients with post-stroke dysphagia was supported by the quantitative analysis.

  15. The contribution of two ears to the perception of vertical angle in sagittal planes.

    PubMed

    Morimoto, M

    2001-04-01

    Because the input signals to the left and right ears are not identical, it is important to clarify the role of these signals in the perception of the vertical angle of a sound source at any position in the upper hemisphere. To obtain basic findings on upper hemisphere localization, this paper investigates the contribution of each pinna to the perception of vertical angle. Tests measured localization of the vertical angle in five planes parallel to the median plane. In the localization tests, the pinna cavities of one or both ears were occluded. Results showed that pinna cavities of both the near and far ears play a role in determining the perceived vertical angle of a sound source in any plane, including the median plane. As a sound source shifts laterally away from the median plane, the contribution of the near ear increases and, conversely, that of the far ear decreases. For saggital planes at azimuths greater than 60 degrees from midline, the far ear no longer contributes measurably to the determination of vertical angle.

  16. Alteration of the end-plane angle in press-fit cylindrical stem radial head prosthesis: an in vitro study.

    PubMed

    Luenam, Suriya; Chalongviriyalert, Piti; Kosiyatrakul, Arkaphat; Thanawattano, Chusak

    2012-01-01

    Many studies comparing the morphology of native radial head with the prosthesis have been published. However, there is limited information regarding the postoperative alignment of the articular surface following the radial head replacement. The purpose of this study is to evaluate the alteration of the end-plane angle in the modular radial head prosthesis with a press-fit cementless cylindrical stem. The study used 36 cadaveric radii. The press-fit size prosthesis with cylindrical stem was inserted into each specimen. The end-plane angles of the radial head before and after prosthetic replacement, were measured in coronal and sagittal planes with a digital inclinometer. The data were analyzed by paired t-test. From paired t-test, there were statistically symmetrical end-plane angles before and after radial head replacement in both coronal and sagittal planes (p-value < 0.01). The mean of radial head end-plane angle alteration in the coronal plane was 3.62° (SD, 2.76°) (range, 0.3°-8.9°). In the sagittal plane, the mean of alteration was 5.85° (SD, 3.56°) degrees (range, 0.3° - 14.2°). The modular radial head prosthesis with cylindrical stem is in vitro able to restore the native end-plane angles of radial heads statistically when used in a press-fit fashion.

  17. Relationship between postural alignment in sitting by photogrammetry and seated postural control in post-stroke subjects.

    PubMed

    Iyengar, Y R; Vijayakumar, K; Abraham, J M; Misri, Z K; Suresh, B V; Unnikrishnan, B

    2014-01-01

    This study was executed to find out correlation between postural alignment in sitting measured through photogrammetry and postural control in sitting following stroke. A cross-sectional study with convenient sampling consisting of 45 subjects with acute and sub-acute stroke. Postural alignment in sitting was measured through photogrammetry and relevant angles were obtained through software MB Ruler (version 5.0). Seated postural control was measured through Function in Sitting Test (FIST). Correlation was obtained using Spearman's Rank Correlation co-efficient in SPSS software (version 17.0). Moderate positive correlation (r = 0.385; p < 0.01) was found between angle of lordosis and angle between acromion, lateral epicondyle and point between radius and ulna. Strong negative correlation (r = -0.435; p < 0.01) was found between cranio-vertebral angle and kyphosis. FIST showed moderate positive correlation (r = 0.3446; p < 0.05) with cranio-vertebral angle and strong positive correlation (r = 0.4336; p < 0.01) with Brunnstrom's stage of recovery in upper extremity. Degree of forward head posture in sitting correlates directly with seated postural control and inversely with degree of kyphosis in sitting post-stroke. Postural control in sitting post-stroke is directly related with Brunnstrom's stage of recovery in affected upper extremity in sitting.

  18. The position of the occlusal plane in natural and artificial dentitions as related to other craniofacial planes.

    PubMed

    Al Quran, Firas A M; Hazza'a, Abdalla; Al Nahass, Nabeel

    2010-12-01

    This study aimed at determining the most reliable ala-tragus line as a guide for the orientation of the occlusal plane in complete denture patients by use of cephalometric landmarks on dentate volunteers. Analysis was made for prosthodontically related craniofacial reference lines and angles of lateral cephalometric radiographs taken for 47 dentate adults. Variables were determined and data were analyzed using SPSS (SPSS, Inc., Chicago, IL). Occlusal plane angle formed between the occlusal plane and Camper's plane had the lowest mean value in the angle formed with Camper's I, which represents the measure taken from the superior border of the tragus of the ear with a score of 2.1°. The highest was measured in the angle formed with Camper's III with a score of 6.1°, while the angle formed with Camper's II was 3.2°. The differences between the three planes in relation to the occlusal plane was significant (p < 0.001). The superior border of the tragus with the inferior border of the ala of the nose was most accurate in orienting the occlusal plane. © 2010 by The American College of Prosthodontists.

  19. An optimized microstructure to minimizing in-plane and through-plane pressure drops of fibrous materials: Counter-intuitive reduction of gas diffusion layer permeability with porosity

    NASA Astrophysics Data System (ADS)

    Sadeghifar, Hamidreza

    2018-05-01

    The present study experimentally investigates the realistic functionality of in-plane and through-plane pressure drops of layered fibrous media with porosity, fiber diameter, fiber spacing, fiber-fiber angles and fiber-flow angles. The study also reveals that pressure drop may increase with porosity and fiber diameter under specific circumstances. This counter-intuitive point narrows down the validity range of widely-used permeability-porosity-diameter models or correlations. It is found that, for fibrous materials, the most important parameter that impacts the in-plane pressure drop is not their porosities but the number of fibers extended in the flow direction. It is also concluded that in-plane pressure drop is highly dependent upon the flow direction (fiber-flow angles), especially at lower porosities. Contrary to in-plane pressure drop, through-plane pressure drop is a weak function of fiber-fiber angles but is strongly impacted by fiber spacing, especially at lower porosities. At a given porosity, low through-plane pressure drops occur if fiber spacing does not change practically from one layer to another. Through-plane pressure drop also, insignificantly, increases with the intersecting angles between fibers. An optimized microstructure of fibrous media resulting in minimal in-plane and through-plane pressure drops is also offered for the first time in this work.

  20. Investigation of an optical sensor for small tilt angle detection of a precision linear stage

    NASA Astrophysics Data System (ADS)

    Saito, Yusuke; Arai, Yoshikazu; Gao, Wei

    2010-05-01

    This paper presents evaluation results of the characteristics of the angle sensor based on the laser autocollimation method for small tilt angle detection of a precision linear stage. The sensor consists of a laser diode (LD) as the light source, and a quadrant photodiode (QPD) as the position-sensing detector. A small plane mirror is mounted on the moving table of the stage as a target mirror for the sensor. This optical system has advantages of high sensitivity, fast response speed and the ability for two-axis angle detection. On the other hand, the sensitivity of the sensor is determined by the size of the optical spot focused on the QPD, which is a function of the diameter of the laser beam projected onto the target mirror. Because the diameter is influenced by the divergence of the laser beam, this paper focuses on the relationship between the sensor sensitivity and the moving position of the target mirror (sensor working distance) over the moving stroke of the stage. The main error components that influence the sensor sensitivity are discussed and the optimal conditions of the optical system of the sensor are analyzed. The experimental result about evaluation of the effective working distance is also presented.

  1. The effects of transverse rotation angle on compression and effective lever arm of prosthetic feet during simulated stance.

    PubMed

    Major, Matthew J; Howard, David; Jones, Rebecca; Twiste, Martin

    2012-06-01

    Unlike sagittal plane prosthesis alignment, few studies have observed the effects of transverse plane alignment on gait and prosthesis behaviour. Changes in transverse plane rotation angle will rotate the points of loading on the prosthesis during stance and may alter its mechanical behaviour. This study observed the effects of increasing the external transverse plane rotation angle, or toe-out, on foot compression and effective lever arm of three commonly prescribed prosthetic feet. The roll-over shape of a SACH, Flex and single-axis foot was measured at four external rotation angle conditions (0°, 5°, 7° and 12° relative to neutral). Differences in foot compression between conditions were measured as average distance between roll-over shapes. Increasing the transverse plane rotation angle did not affect foot compression. However, it did affect the effective lever arm, which was maximized with the 5° condition, although differences between conditions were small. Increasing the transverse plane rotation angle of prosthetic feet by up to 12° beyond neutral has minimal effects on their mechanical behaviour in the plane of walking progression during weight-bearing.

  2. Impact of substrate off-angle on the m-plane GaN Schottky diodes

    NASA Astrophysics Data System (ADS)

    Yamada, Hisashi; Chonan, Hiroshi; Takahashi, Tokio; Shimizu, Mitsuaki

    2018-04-01

    We investigated the effects of the substrate off-angle on the m-plane GaN Schottky diodes. GaN epitaxial layers were grown by metal-organic chemical vapor deposition on m-plane GaN substrates having an off-angle of 0.1, 1.1, 1.7, or 5.1° toward [000\\bar{1}]. The surface of the GaN epitaxial layers on the 0.1°-off substrate consisted of pyramidal hillocks and contained oxygen (>1017 cm-3) and carbon (>1016 cm-3) impurities. The residual carbon and oxygen impurities decreased to <1016 cm-3 when the off-angle of the m-plane GaN substrate was increased. The leakage current of the 0.1°-off m-plane GaN Schottky diodes originated from the +c facet of the pyramidal hillocks. The leakage current was efficiently suppressed through the use of an off-angle that was observed to be greater than 1.1°. The off-angle of the m-plane GaN substrate is critical in obtaining high-performance Schottky diodes.

  3. Hip rotation angle is associated with frontal plane knee joint mechanics during running.

    PubMed

    Sakaguchi, Masanori; Shimizu, Norifumi; Yanai, Toshimasa; Stefanyshyn, Darren J; Kawakami, Yasuo

    2015-02-01

    Inability to control lower extremity segments in the frontal and transverse planes resulting in large knee abduction angle and increased internal knee abduction impulse has been associated with patellofemoral pain (PFP). However, the influence of hip rotation angles on frontal plane knee joint kinematics and kinetics remains unclear. The purpose of this study was to explore how hip rotation angles are related to frontal plane knee joint kinematics and kinetics during running. Seventy runners participated in this study. Three-dimensional marker positions and ground reaction forces were recorded with an 8-camera motion analysis system and a force plate while subjects ran along a 25-m runway at a speed of 4m/s. Knee abduction, hip rotation and toe-out angles, frontal plane lever arm at the knee, internal knee abduction moment and impulse, ground reaction forces and the medio-lateral distance from the ankle joint center to the center of pressure (AJC-CoP) were quantified. The findings of this study indicate that greater hip external rotation angles were associated with greater toe-out angles, longer AJC-CoP distances, smaller internal knee abduction impulses with shorter frontal plane lever arms and greater knee abduction angles. Thus, there appears to exist a conflict between kinematic and kinetic risk factors of PFP, and hip external rotation angle may be a key factor to control frontal plane knee joint kinematics and kinetics. These results may help provide an appropriate manipulation and/or intervention on running style to reduce the risk of PFP. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Cephalometrically assessing the validity of superior, middle and inferior tragus points on ala-tragus line while establishing the occlusal plane in edentulous patient

    PubMed Central

    Thombare, Ram

    2013-01-01

    PURPOSE The purpose of this study was to decide the most appropriate point on tragus to be used as a reference point at time of marking ala tragus line while establishing occlusal plane. MATERIALS AND METHODS The data was collected in two groups of subjects: 1) Dentulous 2) Edentulous group having sample size of 30 for each group with equal gender distribution (15 males, 15 females each). Downs analysis was used for base value. Lateral cephalographs were taken for all selected subjects. Three points were marked on tragus as Superior (S), Middle (M), and Inferior (I) and were joined with ala (A) of the nose to form ala-tragus lines. The angle formed by each line (SA plane, MA plane, IA plane) with Frankfort Horizontal (FH) plane was measured by using custom made device and modified protractor in all dentulous and edentulous subjects. Also, in dentulous subjects angle between Frankfort Horizontal plane and natural occlusal plane was measured. The measurements obtained were subjected to the following statistical tests; descriptive analysis, Student's unpaired t-test and Pearson's correlation coefficient. RESULTS The results demonstrated, the mean angle COO (cant of occlusal plane) as 9.76°, inferior point on tragus had given the mean angular value of IFH [Angle between IA plane (plane formed by joining inferior point-I on tragus and ala of nose- A) and FH plane) as 10.40° and 10.56° in dentulous and edentulous subjects respectively which was the closest value to the angle COO and was comparable with the values of angle COO value in Downs analysis. Angulations of ala-tragus line marked from inferior point with occlusal plane in dentulous subject had given the smallest value 2.46° which showed that this ala-tragus line was nearly parallel to occlusal plane. CONCLUSION The inferior point marked on tragus is the most appropriate point for marking ala-tragus line. PMID:23508068

  5. KAPS (kinematic assessment of passive stretch): a tool to assess elbow flexor and extensor spasticity after stroke using a robotic exoskeleton.

    PubMed

    Centen, Andrew; Lowrey, Catherine R; Scott, Stephen H; Yeh, Ting-Ting; Mochizuki, George

    2017-06-19

    Spasticity is a common sequela of stroke. Traditional assessment methods include relatively coarse scales that may not capture all characteristics of elevated muscle tone. Thus, the aim of this study was to develop a tool to quantitatively assess post-stroke spasticity in the upper extremity. Ninety-six healthy individuals and 46 individuals with stroke participated in this study. The kinematic assessment of passive stretch (KAPS) protocol consisted of passive elbow stretch in flexion and extension across an 80° range in 5 movement durations. Seven parameters were identified and assessed to characterize spasticity (peak velocity, final angle, creep (or release), between-arm peak velocity difference, between-arm final angle, between-arm creep, and between-arm catch angle). The fastest movement duration (600 ms) was most effective at identifying impairment in each parameter associated with spasticity. A decrease in peak velocity during passive stretch between the affected and unaffected limb was most effective at identifying individuals as impaired. Spasticity was also associated with a decreased passive range (final angle) and a classic 'catch and release' as seen through between-arm catch and creep metrics. The KAPS protocol and robotic technology can provide a sensitive and quantitative assessment of post-stroke elbow spasticity not currently attainable through traditional measures.

  6. A novel method of measuring spatial rotation angle using MEMS tilt sensors

    NASA Astrophysics Data System (ADS)

    Cao, Jian'an; Zhu, Xin; Wu, Hao; Zhang, Leping

    2017-10-01

    This paper presents a novel method of measuring spatial rotation angle with a dual-axis micro-electro-mechanical systems tilt sensor. When the sensor is randomly mounted on the surface of the rotating object, there are three unpredictable and unknown mounting position parameters: α, the sensor’s swing angle on the measuring plane; β, the angle between the rotation axis and the horizontal plane; and γ, the angle between the measuring plane and the rotation axis. Thus, the sensor’s spatial rotation model is established to describe the relationship between the measuring axis, rotation axis, and horizontal plane, and the corresponding analytical equations are derived. Furthermore, to eliminate the deviation caused by the uncertain direction of the rotation axis, an extra perpendicularly mounted, single-axis tilt sensor is combined with the dual-axis tilt sensor, forming a three-axis tilt sensor. Then, by measuring the sensors’ three tilts and solving the model’s equations, the object’s spatial rotation angle is obtained. Finally, experimental results show that the developed tilt sensor is capable of measuring spatial rotation angle in the range of  ±180° with an accuracy of 0.2° if the angle between the rotation axis and the horizontal plane is less than 75°.

  7. Reliability of tunnel angle in ACL reconstruction: two-dimensional versus three-dimensional guide technique.

    PubMed

    Leiter, Jeff R S; de Korompay, Nevin; Macdonald, Lindsey; McRae, Sheila; Froese, Warren; Macdonald, Peter B

    2011-08-01

    To compare the reliability of tibial tunnel position and angle produced with a standard ACL guide (two-dimensional guide) or Howell 65° Guide (three-dimensional guide) in the coronal and sagittal planes. In the sagittal plane, the dependent variables were the angle of the tibial tunnel relative to the tibial plateau and the position of the tibial tunnel with respect to the most posterior aspect of the tibia. In the coronal plane, the dependent variables were the angle of the tunnel with respect to the medial joint line of the tibia and the medial and lateral placement of the tibial tunnel relative to the most medial aspect of the tibia. The position and angle of the tibial tunnel in the coronal and sagittal planes were determined from anteroposterior and lateral radiographs, respectively, taken 2-6 months postoperatively. The two-dimensional and three-dimensional guide groups included 28 and 24 sets of radiographs, respectively. Tibial tunnel position was identified, and tunnel angle measurements were completed. Multiple investigators measured the position and angle of the tunnel 3 times, at least 7 days apart. The angle of the tibial tunnel in the coronal plane using a two-dimensional guide (61.3 ± 4.8°) was more horizontal (P < 0.05) than tunnels drilled with a three-dimensional guide (64.7 ± 6.2°). The position of the tibial tunnel in the sagittal plane was more anterior (P < 0.05) in the two-dimensional (41.6 ± 2.5%) guide group compared to the three-dimensional guide group (43.3 ± 2.9%). The Howell Tibial Guide allows for reliable placement of the tibial tunnel in the coronal plane at an angle of 65°. Tibial tunnels were within the anatomical footprint of the ACL with either technique. Future studies should investigate the effects of tibial tunnel angle on knee function and patient quality of life. Case-control retrospective comparative study, Level III.

  8. The wits appraisal using three reference planes and its interaction with the ANB angle among a sub-set of Nigerians".

    PubMed

    Ifesanya, J U; Adeyemi, A T; Otuyemi, O D

    2014-09-01

    Conjoint analysis of orthodontic patients using the Subspinale (A-point) Nasion-Supramentale (B point) (ANB) angle and the Wits appraisal is popular in many practices. This study aimed to present reference values for the Wits appraisal among Nigerians using three horizontal reference planes namely the bisected occlusal plane (BOP), the functional occlusal plane (FOP) and the maxillomandibular angle bisector (MM° bisector) plane. It also assessed the relationship of the Wits appraisal with the ANB angle and its interaction with clinical measures of sagittal skeletal relations among subjects with malocclusion. One hundred participants with normal occlusion and 120 with malocclusion were recruited in the study. Cephalometric radiographs were taken for all participants. Each radiograph was manually traced on a 0.003 matted cellulose acetate tracing paper using a sharpened 2H pencil. The Wits appraisal and ANB angle were determined. Data was analyzed using SPSS version 19. The mean age was 20.7 ± 4.9 years for those with normal occlusion and 18.8 ± 6.5 years in the malocclusion group. There were 91 (41.4%) males and 129 (58.6%) females. Mean values for the Wits appraisal using the BOP as reference, was--1.27 ± 2.91mm, with the FOP, it was -3.54 ± 3.24mm, while with the MM° bisector plane, it was--.75? ± .94mm. The ANB angle showed highest correlation with the MM'°bisector plane Wits value(P< 0 .001). CCONCLUSION: hen the clinical and angular cephalometric findings are at variance, the ANB angle is best moderated by the MM'° isector plane Wits appraisal.

  9. Curved butterfly bileaflet prosthetic cardiac valve

    DOEpatents

    McQueen, David M.; Peskin, Charles S.

    1991-06-25

    An annular valve body having a central passageway for the flow of blood therethrough with two curved leaflets each of which is pivotally supported on an accentric positioned axis in the central passageway for moving between a closed position and an open position. The leaflets are curved in a plane normal to the eccentric axis and positioned with the convex side of the leaflets facing each other when the leaflets are in the open position. Various parameters such as the curvature of the leaflets, the location of the eccentric axis, and the maximum opening angle of the leaflets are optimized according to the following performance criteria: maximize the minimum peak velocity through the valve, maximize the net stroke volume, and minimize the mean forward pressure difference, thereby reducing thrombosis and improving the hemodynamic performance.

  10. An evaluation of relation between the relative parallelism of occlusal plane to ala-tragal line and variation in the angulation of Po-Na-ANS angle in dentulous subjects: A cephalometric study

    PubMed Central

    Shetty, Sanath; Shenoy, K. Kamalakanth; Ninan, Justin; Mahaseth, Pranay

    2015-01-01

    Aims: The aim was to evaluate if any correlation exists between variation in angulation of Po-Na-ANS angle and relative parallelism of the occlusal plane to the different tragal levels of the ear in dentulous subjects. Methodology: A total of 200 subjects were selected for the study. A custom made occlusal plane analyzer was used to determine the posterior point of the ala-tragal line. The lateral cephalogram was shot for each of the subjects. The points Porion, Nasion, and Anterior Nasal Spine were located and the angle formed between these points was measured. Statistical Analysis Used: Fischer's exact test was used to find the correlation between Po-Na-ANS angle and relative parallelism of the occlusal plane to the ala-tragal line at different tragal levels. Results: Statistical analysis showed no significant correlation between Po-Na-ANS angle and relative parallelism of an occlusal plane at different tragal levels, and an inferior point on the tragus was the most common. Conclusion: Irrespective of variations in the Po-Na-ANS angle, no correlation exists between the variation in the angulations of Po-Na-ANS angle and the relative parallelism of occlusal plane to the ala-tragal line at different tragal levels. Furthermore, in a large number of subjects (54%), the occlusal plane was found parallel to a line joining the inferior border of the ala of the nose and the inferior part of the tragus. PMID:26929506

  11. Dynamic balance during walking adaptability tasks in individuals post-stroke.

    PubMed

    Vistamehr, Arian; Balasubramanian, Chitralakshmi K; Clark, David J; Neptune, Richard R; Fox, Emily J

    2018-06-06

    Maintaining dynamic balance during community ambulation is a major challenge post-stroke. Community ambulation requires performance of steady-state level walking as well as tasks that require walking adaptability. Prior studies on balance control post-stroke have mainly focused on steady-state walking, but walking adaptability tasks have received little attention. The purpose of this study was to quantify and compare dynamic balance requirements during common walking adaptability tasks post-stroke and in healthy adults and identify differences in underlying mechanisms used for maintaining dynamic balance. Kinematic data were collected from fifteen individuals with post-stroke hemiparesis during steady-state forward and backward walking, obstacle negotiation, and step-up tasks. In addition, data from ten healthy adults provided the basis for comparison. Dynamic balance was quantified using the peak-to-peak range of whole-body angular-momentum in each anatomical plane during the paretic, nonparetic and healthy control single-leg-stance phase of the gait cycle. To understand differences in some of the key underlying mechanisms for maintaining dynamic balance, foot placement and plantarflexor muscle activation were examined. Individuals post-stroke had significant dynamic balance deficits in the frontal plane across most tasks, particularly during the paretic single-leg-stance. Frontal plane balance deficits were associated with wider paretic foot placement, elevated body center-of-mass, and lower soleus activity. Further, the obstacle negotiation task imposed a higher balance requirement, particularly during the trailing leg single-stance. Thus, improving paretic foot placement and ankle plantarflexor activity, particularly during obstacle negotiation, may be important rehabilitation targets to enhance dynamic balance during post-stroke community ambulation. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. In-cylinder flows of a motored four-stroke engine with flat-crown and slightly concave-crown pistons

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

    Huang, R.F.; Yang, H.S.; Yeh, C.-N.

    2008-04-15

    The temporal and spatial evolution processes of the in-cylinder flow structures and turbulence intensities in the symmetry and offset planes of a motored four-valve, four-stroke engine during the intake and compression strokes are diagnosed by using a particle image velocimeter. Two pistons of different crown shapes (flat-crown and slightly concave-crown pistons) are studied. The inception, establishment, and evolution of the tumbling vortical flow structures during the intake and compression strokes are clearly depicted. Quantitative strengths of the rotating vortical flow motions are presented by a dimensionless parameter, the tumble ratio, which can represent the mean angular velocity of the vorticesmore » in the target plane. The turbulence intensity of the in-cylinder flow is also calculated by using the measured time-varying velocity data. The results show that the flat-crown piston induces higher bulk-averaged tumble ratio and turbulence intensity than the slightly concave-crown piston does because the tumble ratio and turbulence generated by the flat-crown piston in the offset planes during the compression stroke are particularly large. The engine with the flat-crown piston also presents larger torque and power outputs and lower hydrocarbon emission than that with the slightly concave-crown piston. This might be caused by the enhanced combustion in the engine cylinder due to the stronger tumble ratio and turbulence intensity. (author)« less

  13. Validity and Reliability of a Virtual Reality Game in Evaluating the Projected Frontal Plane Knee Angle When Landing From a Drop Vertical Jump.

    PubMed

    Mills, Kathryn; Idris, Aula; Pham, Thu-An; Porte, John; Wiggins, Mark; Kavakli, Manolya

    2017-12-18

    To determine the validity and reliability of the peak frontal plane knee angle evaluated by a virtual reality (VR) netball game when landing from a drop vertical jump (DVJ). Laboratory Methods: Forty participants performed 3 DVJs evaluated by 3-dimensional (3D) motion analysis and 3 DVJs evaluated by the VR game. Limits of agreement for the peak projected frontal plane knee angle and peak knee abduction were determined. Participants were given a consensus category of "Above threshold" or "Below threshold" based on a pre-specified threshold angle of 9˚ during landing. Classification agreement was determined using kappa coefficient and accuracy was determined using specificity and sensitivity. Ten participants returned 1-week later to determine intra-rater reliability, standard error of the measure and typical error. The mean difference in detected frontal plane knee angle was 3.39˚ (1.03˚, 5.74˚). Limits of agreement were -10.27˚ (-14.36˚, -6.19˚) to 17.05˚ (12.97˚, 21.14˚). Substantial agreement, specificity and sensitivity were observed for the threshold classification (ĸ = 0.66, [0.42, 0.88] specificity= 0.96 [0.78, 1.0], sensitivity= 0.75 [0.43, 0.95]). The game exhibited acceptable reliability over time (ICC (3,1) = 0.844) and error was approximately 2˚. The VR game reliably evaluated a projected frontal plane knee angle. While the knee angle detected by the VR game is strongly related peak knee abduction, the accuracy of detecting the exact angle was limited. A threshold approach may be a more accurate approach for gaming technology to evaluate frontal plane knee angles when landing from a jump.

  14. {l_angle}110{r_angle} dendrite growth in aluminum feathery grains

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

    Henry, S.; Rappaz, M.; Jarry, P.

    1998-11-01

    Automatic indexing of electron backscattered diffraction patterns, scanning electron microscopy, and optical microscopy observations have been carried out on aluminum-magnesium-silicon, aluminum-copper, and aluminum-silicon alloys directionally solidified or semicontinuously cast using the direct chill casting process. From these combined observations, it is shown that the feathery grains are made of {l_angle}110{r_angle} primary dendrite trunks (e.g., [011{bar 1}]) split in their centers by a coherent (111) twin plane. The average spacing of the dendrite trunks in the twin plane (about 10 to 20 {micro}m) is typically one order of magnitude smaller than that separating successive rows of trunks (or twin planes). Themore » [011{bar 1}] orientation of these trunks is close to the thermal gradient direction (typically within 15 deg)--a feature probably resulting from a growth competition mechanism similar to that occurring during normal <100> columnar dendrite growth. On both sides of these trunks, secondary dendrite arms also grow along {l_angle}110{r_angle} directions. Their impingement creates wavy noncoherent twin boundaries between the coherent twin planes. In the twin plane, evidence is shown that {l_angle}110{r_angle} branching mechanisms lead to the propagation of the twinned regions, to the regular arrangement of the primary dendrite trunks along a [{bar 2}11] direction, and to coherent planar twin boundaries. From these observations, it is concluded that the feathery grains are probably the result of a change from a normal <100> to a {l_angle}110{r_angle} surface tension/attachment kinetics anisotropy growth mode. Finally, the proposed mechanisms of leathery grain growth are further supported by the observation of {l_angle}110{r_angle} dendrite growth morphologies in thin aluminum-zinc coatings.« less

  15. Centre-based restricted nearest feature plane with angle classifier for face recognition

    NASA Astrophysics Data System (ADS)

    Tang, Linlin; Lu, Huifen; Zhao, Liang; Li, Zuohua

    2017-10-01

    An improved classifier based on the nearest feature plane (NFP), called the centre-based restricted nearest feature plane with the angle (RNFPA) classifier, is proposed for the face recognition problems here. The famous NFP uses the geometrical information of samples to increase the number of training samples, but it increases the computation complexity and it also has an inaccuracy problem coursed by the extended feature plane. To solve the above problems, RNFPA exploits a centre-based feature plane and utilizes a threshold of angle to restrict extended feature space. By choosing the appropriate angle threshold, RNFPA can improve the performance and decrease computation complexity. Experiments in the AT&T face database, AR face database and FERET face database are used to evaluate the proposed classifier. Compared with the original NFP classifier, the nearest feature line (NFL) classifier, the nearest neighbour (NN) classifier and some other improved NFP classifiers, the proposed one achieves competitive performance.

  16. Expertise of using striking techniques for power stroke in badminton.

    PubMed

    Zhu, Qin

    2013-10-01

    Two striking techniques (fast swing and angled striking) were examined to see if they allowed effective use of string tension for the power stroke in badminton. 12 participants (4 novices, 4 recreational, and 4 expert badminton players) were recorded by a fast-speed camera while striking a shuttlecock with racquets of 8 different string tensions. The peak speed of the shuttlecock, the racquet angle and the shuttlecock angle were analyzed. The results showed that expert players succeeded in using both striking techniques to overcome the constraint of string tension and produce a consistently superior stroke. Failure to use either striking technique resulted in inferior performance that was constrained by string tension. Expertise in badminton allows the necessary motor adjustments based on the affordance perception of the string tension.

  17. Wavelength dependent in-plane birefringence of transparent flexible films determined by using transmission ellipsometry

    NASA Astrophysics Data System (ADS)

    Yang, Sung Mo; Hong, Sera; Kim, Sang Youl

    2018-05-01

    We introduce a simple method to determine the in-plane birefringence of transparent flexible films by using transmission spectroscopic ellipsometry. The pseudo-ellipsometric constants which can represent their sample azimuthal angle dependent characteristics are introduced. The effect of in-plane birefringence and sample azimuthal angle on the pseudo ellipsometric constants is calculated using Jones matrix formalism, and the observed sample azimuthal angle dependence of measured pseudo-ellipsometric data is well understood. Wavelength dependence of in-plane birefringence is expressed in terms of the Sellmeier dispersion equation. The best fit pseudo-ellipsometric spectra to the measured ones at the sample azimuthal angles of every 15° from 0 to 90° are searched. The dispersion coefficients of the Sellmeier equation and the azimuthal angle of the optic axis are determined for polycarbonate (PC), poly(ethylene naphthalate) (PEN), poly(ethylene terephthalate) (PET), polyimide (PI), and colorless polyimide (CPI) films.

  18. Relationships between clubshaft motions and clubface orientation during the golf swing.

    PubMed

    Takagi, Tokio; Yokozawa, Toshiharu; Inaba, Yuki; Matsuda, Yuji; Shiraki, Hitoshi

    2017-09-01

    Since clubface orientation at impact affects ball direction and ball spin, the ability to control clubface orientation is one of the most important skills for golfers. This study presents a new method to describe clubface orientation as a function of the clubshaft motions (i.e., swing plane orientation, clubshaft angle in the swing plane, and clubshaft rolling angle) during a golf swing and investigates the relationships between the clubshaft motions and clubface orientation at impact. The club motion data of driver shots were collected from eight skilled golfers using a three-dimensional motion capture system. The degrees of influence of the clubshaft motions on the clubface orientation were investigated using sensitivity analysis. The sensitivity analysis revealed that the swing plane horizontal angle affected the clubface horizontal angle to an extent of 100%, that the clubshaft angle in the swing plane affected both the clubface vertical and horizontal angles to extents of 74 and 68%, respectively, and that the clubshaft rolling angle affected both the clubface vertical and horizontal angles to extents of -67 and 75%, respectively. Since the method presented here relates clubface orientation to clubshaft motions, it is useful for understanding the clubface control of a golfer.

  19. Verticality Perceptions Associate with Postural Control and Functionality in Stroke Patients

    PubMed Central

    Baggio, Jussara A. O.; Mazin, Suleimy S. C.; Alessio-Alves, Frederico F.; Barros, Camila G. C.; Carneiro, Antonio A. O.; Leite, João P.; Pontes-Neto, Octavio M.; Santos-Pontelli, Taiza E. G.

    2016-01-01

    Deficits of postural control and perceptions of verticality are disabling problems observed in stroke patients that have been recently correlated to each other. However, there is no evidence in the literature confirming this relationship with quantitative posturography analysis. Therefore, the objectives of the present study were to analyze the relationship between Subjective Postural Vertical (SPV) and Haptic Vertical (HV) with posturography and functionality in stroke patients. We included 45 stroke patients. The study protocol was composed by clinical interview, evaluation of SPV and HV in roll and pitch planes and posturography. Posturography was measured in the sitting and standing positions under the conditions: eyes open, stable surface (EOSS); eyes closed, stable surface (ECSS); eyes open, unstable surface (EOUS); and eyes closed, unstable surface (ECUS). The median PV in roll plane was 0.34° (-1.44° to 2.54°) and in pitch plane 0.36° (-2.72° to 2.45°). The median of HV in roll and pitch planes were -0.94° (-5.86° to 3.84°) and 3.56° (-0.68° to 8.36°), respectively. SPV in the roll plane was correlated with all posturagraphy parameters in sitting position in all conditions (r = 0.35 to 0.47; p < 0.006). There were moderate correlations with the verticality perceptions and all the functional scales. Linear regression model showed association between speed and SPV in the roll plane in the condition EOSS (R2 of 0.37; p = 0.005), in the condition ECSS (R2 of 0.13; p = 0.04) and in the condition EOUS (R2 of 0.22; p = 0.03). These results suggest that verticality perception is a relevant component of postural control and should be systematically evaluated, particularly in patients with abnormal postural control. PMID:26954679

  20. Aeroballistics of Corkscrew Projectiles

    DTIC Science & Technology

    1978-06-01

    obtained by cutting a solid cylinder with a series of six skewed planes to obtain the con- figuration shown in Figure 1. Three skewed planes form the...respect to the cylinder centerline can be varied; however, the angles of the three. nose planes must be the same as well as the angles of the three...b) At low angles of attack, the Magnus forces and moments are small at all spin rates near the configuration twist. This is due to the zero spin

  1. The effect of cleft maxillary distraction osteogenesis on the levator veli palatini and velopharyngeal function.

    PubMed

    Chen, Philip Kuo-Ting; Por, Yong-Chen; Liou, Eric Jein-Wein; Chang, Frank Chun-Shin

    2015-05-01

    Le Fort I maxillary distraction with the rigid external distraction (RED) device is performed to correct severe midface retrusion in cleft patients, but it may adversely affect velopharyngeal function. This study aims to investigate the angular changes in the levator veli palatini (LVP) and its influence on velopharyngeal function after maxillary distraction using 3-dimensional computed tomography (3D CT) scan volume rendered images. This was a retrospective study of 12 patients. Group 1 had no velopharyngeal function deterioration and group 2 had velopharyngeal function deterioration. Preoperative and 1 year postoperative CT scans were analyzed with Mimics v10 software. Segmentation of the LVP and the nasopharyngeal airway was performed and volumetric images were obtained. Six measurements were made: (1) the angle between the levator plane and the Frankfort horizontal, (2) the angle between the levator plane and the soft palate plane, (3) the angle between the 2 LVP muscles, (4) the pharyngeal depth, and (5, 6) the movement of the inferior pharyngeal point with respect to the horizontal and vertical planes. The independent samples t test, Mann-Whitney test, and paired t tests were used for statistical analyses (P < 0.05). Group 2 had statistically significant reduction in the angle between the levator plane and Frankfort horizontal as well as the soft palate plane. Group 1 had a statistically significant increase in the pharyngeal depth and movement of the inferior pharyngeal point with respect to the horizontal plane. A decrease in the angle between the levator plane and the Frankfort horizontal or the soft palate plane was associated with velopharyngeal function deterioration.

  2. Investigation the effect of lattice angle on the band gap width in 3D phononic crystals with rhombohedral(I) lattice

    NASA Astrophysics Data System (ADS)

    Salehi, H.; Aryadoust, M.; Shoushtari, M. Zargar

    2014-07-01

    In this paper, the propagation of acoustic waves in the phononic crystal of 3D with rhombohedral(I) lattice is studied theoretically. The crystal composite constituted of nickel spheres embedded in epoxy. The calculations of the band structure and density of states are performed with the plane wave expansion method in the irreducible part of Brillouin zone. In the present work, we have investigated the effect of lattice angle on the band structure and width of the band gap rhombohedral(I) lattice in the irreducible part of the first Brillouin zone and its planes separately. The results show that more than one complete band gape are formed in the four planes of the irreducible part. The most complete band gaps are formed in the (111) plane and the widest complete band gap in (443) with an angle greater than 80. So, if the sound passes through the (111) and (443) planes for the lattice angle close to 90, the crystal phononic displays the excellent insulation behavior. Moreover, in the other planes, the lattice angle does not affect on the width and the number of band gaps. Also, for the filling fraction 5 %, the widest complete band gap is formed. These results are consistent with the effect of symmetry on the band gap width, because the (111) plane has the most symmetry.

  3. An Investigation of the Fundamental Cause of Asymmetric Separated Flow

    DTIC Science & Technology

    1992-10-01

    with respect to the geometric symmetry plane as long as the free-stream velocity vector remains in this plane. At angles of attack higher than a ...separation points and sit above the nose near the lee plane of " symmetry ." Below a critical angle of attack, the lee plane is indeed a plane about which...line model was a breakthrough in understanding this phenomenon. Dyer, Fiddes, and Smith (Ref 7) found a bifurcation in the solution to the small

  4. Reflection coefficient of qP, qS and SH at a plane boundary between viscoelastic TTI media

    NASA Astrophysics Data System (ADS)

    Wang, Hongwei; Peng, Suping

    2016-01-01

    This paper introduces a calculation method for the effective elastic stiffness tensor matrix of the viscous-elastic TTI medium based on the Chapman theory. We then obtain the phase velocity formula and seismic wave polarization formula of the viscous-elastic TTI medium, by solving the Christoffel equation; solve the phase angle of reflection and transmission wave through the numerical method in accordance with the wave slowness ellipsoid; on the basis of this assumption, and assuming that qP, qS and SH waves occurred simultaneously at the viscous-elastic anisotropic interface, establish the sixth-order Zoeppritz equation in accordance with the boundary conditions; establish the models for the upper and lower media which are viscous-elastic HTI, TTI, etc., on the basis of the sixth-order Zoeppritz equation; and study the impact of fracture dip angle, azimuth angle and frequency on the reflection coefficient. From this we obtain the following conclusions: the reflection coefficient can identify the fracture strike and dip when any information pertaining to the media is unknown; dispersion phenomenon is obvious on the axial plane of symmetry and weakened in the plane vertical to the axial plane of symmetry; the vertical-incidence longitudinal wave can stimulate the qS wave when the dip angle is not 0° or 90° under the condition of coincidence between the symmetry planes of the upper and lower media; when the symmetry planes of the upper and lower media do not coincide and the dip angle is not 0° or 90°, then the vertical-incidence qP will stimulate the qS and SH waves at the same time; the dip angle can cause the reflection coefficient curve to have a more obvious dispersion phenomenon, while the included angle between the symmetry planes of the upper and lower media will weaken the dispersion except SH; and the intercept of reflection coefficient is affected by the fracture dip and included angle between the symmetry planes of the upper and lower media.

  5. Method of Generating X-Ray Diffraction Data for Integral Detection of Twin Defects in Super-Hetero-Epitaxial Materials

    NASA Technical Reports Server (NTRS)

    Park, Yeonjoon (Inventor); Choi, Sang Hyouk (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor)

    2009-01-01

    A method provides X-ray diffraction (XRD) data suitable for integral detection of a twin defect in a strained or lattice-matched epitaxial material made from components having crystal structures having symme try belonging to different space groups. The material is mounted in a n X-ray diffraction (XRD) system. In one embodiment, the XRD system's goniometer angle Omega is set equal to (Theta(sub B)-Beta) where The ta(sub B) is a Bragg angle for a designated crystal plane of the allo y that is disposed at a non-perpendicular orientation with respect to the {111) crystal plane, and Beta is the angle between the designate d crystal plane and a { 111 } crystal plane of one of the epitaxial components. The XRD system's detector angle is set equal to (Theta(su b B)+Beta). The material can be rotated through an angle of azimuthal rotation Phi about the axis aligned with the material. Using the det ector, the intensity of the X-ray diffraction is recorded at least at the angle at which the twin defect occurs.

  6. Design of angle-resolved illumination optics using nonimaging bi-telecentricity for 193 nm scatterfield microscopy.

    PubMed

    Sohn, Martin Y; Barnes, Bryan M; Silver, Richard M

    2018-03-01

    Accurate optics-based dimensional measurements of features sized well-below the diffraction limit require a thorough understanding of the illumination within the optical column and of the three-dimensional scattered fields that contain the information required for quantitative metrology. Scatterfield microscopy can pair simulations with angle-resolved tool characterization to improve agreement between the experiment and calculated libraries, yielding sub-nanometer parametric uncertainties. Optimized angle-resolved illumination requires bi-telecentric optics in which a telecentric sample plane defined by a Köhler illumination configuration and a telecentric conjugate back focal plane (CBFP) of the objective lens; scanning an aperture or an aperture source at the CBFP allows control of the illumination beam angle at the sample plane with minimal distortion. A bi-telecentric illumination optics have been designed enabling angle-resolved illumination for both aperture and source scanning modes while yielding low distortion and chief ray parallelism. The optimized design features a maximum chief ray angle at the CBFP of 0.002° and maximum wavefront deviations of less than 0.06 λ for angle-resolved illumination beams at the sample plane, holding promise for high quality angle-resolved illumination for improved measurements of deep-subwavelength structures using deep-ultraviolet light.

  7. Parametric Investigation on the Use of Lateral and Logitudinal Rotor Trim Flapping for Tiltrotor Noise Reduction

    NASA Technical Reports Server (NTRS)

    Malpica, Carlos

    2017-01-01

    This paper presents an acoustics parametric study of the effect of varying lateral and longitudinal rotor trim flapping angles (tip-path-plane tilt) on noise radiated by an isolated 26-ft diameter proprotor, similar to that of the AW609 tiltrotor, in edgewise flight. Three tip-path-plane angle of attack operating conditions of -9, 0 and 6 deg, at 80 knots, were investigated. Results showed that: 1) minimum noise was attained for the tip-path-plane angle of attack value of -9 deg, and 2) changing the cyclic trim state (i.e., controls) altered the airloads and produced noticeable changes to the low-frequency (LF) and blade-vortex interaction (BVI) radiated-noise magnitude and directionality. In particular, by trimming the rotor to a positive (inboard) lateral flapping angle of 4 deg, further reductions up to 3 dB in the low-frequency noise sound pressure level were attained without significantly impacting the BVI noise for longitudinal tip-path-plane angles of -9 and 6 deg.

  8. The Dance of the Foci

    ERIC Educational Resources Information Center

    Seppala-Holtzman, David

    2010-01-01

    It's well known that slicing a cone with a plane and then allowing the plane to rotate through all possible angles of inclination yields the conic sections. What paths then do the foci of these conics trace out as this cutting plane passes through the different angles? In this article, we derive formulae for these trajectories and generate the…

  9. Acetabular overcoverage in the horizontal plane: an underdiagnosed trigger of early hip arthritis. A CT scan study in young adults.

    PubMed

    Valera, Màrius; Ibáñez, Natalia; Sancho, Rogelio; Llauger, Jaume; Gich, Ignasi

    2018-01-01

    Acetabular overcoverage promotes hip osteoarthritis causing a pincer-type femoroacetabular impingement. Acetabular coverage in the horizontal plane is usually poorly defined in imaging studies and may be misdiagnosed. The goal of this study was to analyze the role of acetabular overcoverage measured in the frontal plane and in the horizontal plane by CT scan and to determine its relationship with other anatomic features in the onset of hip arthritis in young adults. We compared prospectively CT scans from two groups of adults of 55 years or younger: the patient group (n = 30) consisted of subjects with diagnosis of early hip arthritis (Tönnis Grade I or II) and the control group (n = 31) consisted of subjects with healthy hips. Two independent observers analyzed centre edge angle (CEA), acetabular anteversion angle (AAA), anterior sector acetabular angle (AASA), posterior sector acetabular angle (PASA), horizontal acetabular sector angle (HASA), femoral anteversion angle (FAVA), alpha angle (AA), and Mckibbin Instability Index (MI). Angles measuring the acetabular coverage on the horizontal plane (AASA, PASA and, HASA) were significantly higher in the patient group (p < 0.001, p = 0.03 and p < 0.001, respectively). Pearson's correlation coefficient showed a positive correlation between CEA and HASA in patients (r = 0.628) and in controls (r = 0.660). However, a high CEA (> 35º) was strongly associated with a high HASA (> 160º) in patients (p = 0.024) but not in controls (p = 0.21), suggesting that pincer should be simultaneously present in the horizontal and frontal plane to trigger hip degeneration. No significant association was detected between a high alpha angle (> 60º) and a high CEA (> 35º suggesting that a mixed pincer-cam aetiology was not prevalent in our series. Multivariate regression analysis showed the most significant predictors of degenerative joint disease were HASA (p = 0.008), AA (p = 0.048) and ASAA (p = 0.004). Acetabular overcoverage in the horizontal plane plays an important role in the onset of early hip arthritis. Considering that this condition is usually underdiagnosed, we suggest the anterior sector acetabular angle, the posterior sector acetabular angle, and the horizontal acetabular sector angles be routinely included in decision-making algorithms in hip conservative surgery to better define hips-at-risk of developing early hip osteoarthritis.

  10. Motion-aware stroke volume quantification in 4D PC-MRI data of the human aorta.

    PubMed

    Köhler, Benjamin; Preim, Uta; Grothoff, Matthias; Gutberlet, Matthias; Fischbach, Katharina; Preim, Bernhard

    2016-02-01

    4D PC-MRI enables the noninvasive measurement of time-resolved, three-dimensional blood flow data that allow quantification of the hemodynamics. Stroke volumes are essential to assess the cardiac function and evolution of different cardiovascular diseases. The calculation depends on the wall position and vessel orientation, which both change during the cardiac cycle due to the heart muscle contraction and the pumped blood. However, current systems for the quantitative 4D PC-MRI data analysis neglect the dynamic character and instead employ a static 3D vessel approximation. We quantify differences between stroke volumes in the aorta obtained with and without consideration of its dynamics. We describe a method that uses the approximating 3D segmentation to automatically initialize segmentation algorithms that require regions inside and outside the vessel for each temporal position. This enables the use of graph cuts to obtain 4D segmentations, extract vessel surfaces including centerlines for each temporal position and derive motion information. The stroke volume quantification is compared using measuring planes in static (3D) vessels, planes with fixed angulation inside dynamic vessels (this corresponds to the common 2D PC-MRI) and moving planes inside dynamic vessels. Seven datasets with different pathologies such as aneurysms and coarctations were evaluated in close collaboration with radiologists. Compared to the experts' manual stroke volume estimations, motion-aware quantification performs, on average, 1.57% better than calculations without motion consideration. The mean difference between stroke volumes obtained with the different methods is 7.82%. Automatically obtained 4D segmentations overlap by 85.75% with manually generated ones. Incorporating motion information in the stroke volume quantification yields slight but not statistically significant improvements. The presented method is feasible for the clinical routine, since computation times are low and essential parts run fully automatically. The 4D segmentations can be used for other algorithms as well. The simultaneous visualization and quantification may support the understanding and interpretation of cardiac blood flow.

  11. Comparable ultrasound measurements of ten anatomical specimens of infant hip joints by the methods of Graf and Terjesen.

    PubMed

    Falliner, A; Hahne, H J; Hedderich, J; Brossmann, J; Hassenpflug, J

    2004-04-01

    To define which sonographic section planes relative to the acetabular inlet plane will produce analyzable images with the methods of Graf and Terjesen. Anatomical specimens of infant hip joints were investigated in a water bath using the methods of Graf and Terjesen. Acetabular position was varied in defined increments with respect to the ultrasound beam. The alpha angles and the femoral head coverage (FHC) were measured. To obtain images analyzable by the two methods, the ultrasound beam had to intersect with the acetabular inlet plane at defined angles. The acetabular notch had to be anteriorly rotated from the ultrasound beam plane by at least 20 degrees. Beam entry within a 50 degrees sector posterior to the perpendicular on the inlet plane resulted in analyzable images. The stepwise multiple linear regression analysis showed that alpha angles and FHC were much affected by the coronal-plane transducer tilt. The fact that caudal tilts of the transducer are associated with reduced alpha angles and FHC values should be kept in mind in clinical ultrasound investigations. It is recommended that the transducer should be put on the greater trochanter perpendicular to the transverse axis of the body.

  12. Method and apparatus for optimizing the efficiency and quality of laser material processing

    DOEpatents

    Susemihl, Ingo

    1990-01-01

    The efficiency of laser welding and other laser material processing is optimized according to this invention by rotating the plane of polarization of a linearly polarized laser beam in relation to a work piece of the material being processed simultaneously and in synchronization with steering the laser beam over the work piece so as to keep the plane of polarization parallel to either the plane of incidence or the direction of travel of the beam in relation to the work piece. Also, depending to some extent on the particular processing being accomplished, such as welding or fusing, the angle of incidence of the laser beam on the work piece is kept at or near the polarizing or Brewster's angle. The combination of maintaining the plane of polarization parallel to plane of incidence while also maintaining the angle of incidence at or near the polarizing or Brewster's angle results in only minimal, if any, reflection losses during laser welding. Also, coordinating rotation of the plane of polarization with the translation or steering of a work piece under a laser cutting beam maximizes efficiency and kerf geometry, regardless of the direction of cut.

  13. Method and apparatus for optimizing the efficiency and quality of laser material processing

    DOEpatents

    Susemihl, I.

    1990-03-13

    The efficiency of laser welding and other laser material processing is optimized according to this invention by rotating the plane of polarization of a linearly polarized laser beam in relation to a work piece of the material being processed simultaneously and in synchronization with steering the laser beam over the work piece so as to keep the plane of polarization parallel to either the plane of incidence or the direction of travel of the beam in relation to the work piece. Also, depending to some extent on the particular processing being accomplished, such as welding or fusing, the angle of incidence of the laser beam on the work piece is kept at or near the polarizing or Brewster's angle. The combination of maintaining the plane of polarization parallel to plane of incidence while also maintaining the angle of incidence at or near the polarizing or Brewster's angle results in only minimal, if any, reflection losses during laser welding. Also, coordinating rotation of the plane of polarization with the translation or steering of a work piece under a laser cutting beam maximizes efficiency and kerf geometry, regardless of the direction of cut. 7 figs.

  14. Three-Dimensional Ankle Moments and Nonlinear Summation of Rat Triceps Surae Muscles

    PubMed Central

    Tijs, Chris; van Dieën, Jaap H.; Baan, Guus C.; Maas, Huub

    2014-01-01

    The Achilles tendon and epimuscular connective tissues mechanically link the triceps surae muscles. These pathways may cause joint moments exerted by each muscle individually not to sum linearly, both in magnitude and direction. The aims were (i) to assess effects of sagittal plane ankle angle (varied between 150° and 70°) on isometric ankle moments, in both magnitude and direction, exerted by active rat triceps surae muscles, (ii) to assess ankle moment summation between those muscles for a range of ankle angles and (iii) to assess effects of sagittal plane ankle angle and muscle activation on Achilles tendon length. At each ankle angle, soleus (SO) and gastrocnemius (GA) muscles were first excited separately to assess ankle-angle moment characteristics and subsequently both muscles were excited simultaneously to investigate moment summation. The magnitude of ankle moment exerted by SO and GA, the SO direction in the transverse and sagittal planes, and the GA direction in the transverse plane were significantly affected by ankle angle. SO moment direction in the frontal and sagittal planes were significantly different from that of GA. Nonlinear magnitude summation varied between 0.6±2.9% and −3.6±2.9%, while the nonlinear direction summation varied between 0.3±0.4° and −0.4±0.7° in the transverse plane, between 0.5±0.4° and 0.1±0.4° in the frontal plane, and between 3.0±7.9° and 0.3±2.3° in the sagittal plane. Changes in tendon length caused by SO contraction were significantly lower than those during contraction of GA and GA+SO simultaneously. Thus, moments exerted by GA and SO sum nonlinearly both in the magnitude and direction. The limited degree of nonlinear summation may be explained by different mechanisms acting in opposite directions. PMID:25360524

  15. Canine sacroiliac luxation: anatomic study of the craniocaudal articular surface angulation of the sacrum to define a safe corridor in the dorsal plane for placement of screws used for fixation in lag fashion.

    PubMed

    Bowlt, Kelly L; Shales, Christopher J

    2011-01-01

    To define a safe corridor in the dorsal plane relative to the articular surface for placement of a single screw in lag fashion to achieve stabilization of sacroiliac luxation in the dog. Cadaveric study. Dorsoventral radiographs of denuded canine sacra (n=49) were taken to determine the safe corridor in the craniocaudal plane, and the maximum, optimum and minimum angles were calculated that would allow a screw inserted in lag fashion to engage at least 60% of the width of the sacral body without cranial or caudal penetration through the bone. The mean safe corridor in the dorsal plane is ∼24° wide. Mean craniocaudal minimum, optimum and maximum drill angles from the drill start point were 88°, 100°, and 111° from the articular surface, respectively. No single angle will completely avoid risk of screw penetration beyond the safe corridor cranially and caudally. There is sufficient anatomic variation between different canine sacra that a single angle cannot be recommended for screw placement in the dorsal plane. A standard angle cannot be recommended for screw placement in lag fashion within the canine sacrum in the dorsal plane. Because of the narrow width of the safe corridor, preoperative measurements on radiographs are recommended and a range of angled drill guides may be useful to decrease surgeon margin of error. © Copyright 2010 by The American College of Veterinary Surgeons.

  16. Method for preparing high temperature superconductor

    DOEpatents

    Balachandran, Uthamalingam; Chudzik, Michael P.

    2002-01-01

    A method of depositing a biaxially textured metal oxide on a substrate defining a plane in which metal oxide atoms are vaporized from a source to form a plume of metal oxide atoms. Atoms in the plume disposed at a selected angle in a predetermined range of angles to the plane of the substrate are allowed to contact the substrate while preventing atoms outside a selected angle from reaching the substrate. The preferred range of angles is 40.degree.-70.degree. and the preferred angle is 60.degree..+-.5.degree.. A moving substrate is disclosed.

  17. A study of parallelism of the occlusal plane and ala-tragus line.

    PubMed

    Sadr, Katayoun; Sadr, Makan

    2009-01-01

    Orientation of the occlusal plane is one of the most important clinical procedures in prostho-dontic rehabilitation of edentulous patients. The aim of this study was to define the best posterior reference point of ala-tragus line for orientation of occlusal plane for complete denture fabrication. Fifty-three dental students (27 females and 26 males) with complete natural dentition and Angel's Class I occlusal relationship were selected. The subjects were photographed in natural head position while clenching on a Fox plane. After tracing the photographs, the angles between the following lines were measured: the occlusal plane (Fox plane) and the superior border of ala-tragus, the occlusal plane (Fox plane) and the middle of ala-tragus as well as the occlusal plane (Fox plane) and the inferior border of ala-tragus. Descriptive statistics, one sample t-test and independent t-test were used. P value less than 0.05 was considered significant. There was no parallelism between the occlusal plane and ala-tragus line with three different posterior ends and one sample t-test showed that the angles between them were significantly different from zero (p<0.05). However, the supe-rior border of ala-tragus line had the lowest mean angle, 1.80° (3.12) and was almost parallel to the occlusal plane. The superior border of the tragus is suggested as the posterior reference for ala-tragus line.

  18. Use of computed tomography to define a sacral safe corridor for placement of 2.7 mm cortical screws in feline sacroiliac luxation.

    PubMed

    Philp, Helen; Durand, Alexane; De Vicente, Felipe

    2018-06-01

    Objectives This study aimed to define a safe corridor for 2.7 mm cortical sacroiliac screw insertion in the dorsal plane (craniocaudal direction) using radiography and CT, and in the transverse plane (dorsoventral direction) using CT in feline cadavers. A further aim was to compare the values obtained by CT with those previously reported by radiography in the transverse plane. Methods Thirteen pelvises were retrieved from feline cadavers and dissected to expose one of the articular surfaces of the sacrum. A 2.7 mm screw was placed in the sacrum to a depth of approximately 1 cm in each exposed articular surface. Dorsoventral radiography and CT scanning of each specimen were performed. Multiplanar reconstructions were performed to allow CT evaluation in both the dorsal and transverse planes. Calculations were made to find the maximum, minimum and optimum angles for screw placement in craniocaudal (radiography and CT) and dorsoventral (CT) directions when using a 2.7 mm cortical screw. Results Radiographic measurement showed a mean optimum craniocaudal angle of 106° (range 97-112°). The mean minimum angle was 95° (range 87-107°), whereas the mean maximum angle was 117° (108-124°). Measurement of the dorsal CT scan images showed a mean optimum craniocaudal angle of 101° (range 94-110°). The mean minimum angle was 90° (range 83-99°), whereas the mean maximum angle was 113° (104-125°). The transverse CT scan images showed a mean dorsoventral minimum angle of 103° (range 95-113°), mean maximum angle of 115° (104-125°) and mean optimum dorsoventral angle of 111° (102-119°). Conclusions and relevance An optimum craniocaudal angle of 101° is recommended for 2.7 mm cortical screw placement in the feline sacral body, with a safety margin between 99° and 104°. No single angle can be recommended in the dorsoventral direction and therefore preoperative measuring on individual cats using CT images is recommended to establish the ideal individual angle in the transverse plane.

  19. Vibration-Assisted Femtosecond Laser Drilling with Controllable Taper Angles for AMOLED Fine Metal Mask Fabrication.

    PubMed

    Choi, Wonsuk; Kim, Hoon Young; Jeon, Jin Woo; Chang, Won Seok; Cho, Sung-Hak

    2017-02-21

    This study investigates the effect of focal plane variation using vibration in a femtosecond laser hole drilling process on Invar alloy fabrication quality for the production of fine metal masks (FMMs). FMMs are used in the red, green, blue (RGB) evaporation process in Active Matrix Organic Light-Emitting Diode (AMOLED) manufacturing. The taper angle of the hole is adjusted by attaching the objective lens to a micro-vibrator and continuously changing the focal plane position. Eight laser pulses were used to examine how the hole characteristics vary with the first focal plane's position, where the first pulse is focused at an initial position and the focal planes of subsequent pulses move downward. The results showed that the hole taper angle can be controlled by varying the amplitude of the continuously operating vibrator during femtosecond laser hole machining. The taper angles were changed between 31.8° and 43.9° by adjusting the vibrator amplitude at a frequency of 100 Hz. Femtosecond laser hole drilling with controllable taper angles is expected to be used in the precision micro-machining of various smart devices.

  20. Control for small-speed lateral flight in a model insect.

    PubMed

    Zhang, Yan Lai; Sun, Mao

    2011-09-01

    Controls required for small-speed lateral flight of a model insect were studied using techniques based on the linear theories of stability and control (the stability and control derivatives were computed by the method of computational fluid dynamics). The main results are as follows. (1) Two steady-state lateral motions can exist: one is a horizontal side translation with the body rolling to the same side of the translation by a small angle, and the other is a constant-rate yaw rotation (rotation about the vertical axis). (2) The side translation requires an anti-symmetrical change in the stroke amplitudes of the contralateral wings, and/or an anti-symmetrical change in the angles of attack of the contralateral wings, with the down- and upstroke angles of attack of a wing having equal change. The constant-rate yaw rotation requires an anti-symmetrical change in the angles of attack of the contralateral wings, with the down- and upstroke angles of attack of a wing having differential change. (3) For the control of the horizontal side translation, control input required for the steady-state motion has an opposite sign to that needed for initiating the motion. For example, to have a steady-state left side-translation, the insect needs to increase the stroke amplitude of the left wing and decrease that of the right wing to maintain the steady-state flight, but it needs an opposite change in stroke amplitude (decreasing the stroke amplitude of the left wing and increasing that of the right wing) to enter the flight.

  1. The mechanisms of the SAMS experiment flown on Nimbus 7 with particular reference to the 2 axis scanning mirror. [infrared radiometer for stratospheric and mesospheric investigations

    NASA Technical Reports Server (NTRS)

    Hadley, H.

    1980-01-01

    The stratospheric and mesospheric sounder (SAMS) experiment on Nimbus 7 includes a 2 axis scanning mirror and 7 pressure modulator cells. The SAMS experiment is a limb sounding instrument to measure the temperature profile and minor constituents of the atmosphere. The limb scan requires small mirror steps over a 3 deg range, while the scan in azimuth is in larger steps over a 15 deg range. The mirror is plane, 20 cm in diameter, and of zero expansion glass-ceramic. It is supported on two tilt tables, fitted one on the other, with the axes at right angles. The angle of tilt is adjusted by means of recirculating ball screws which are ion plated with lead for lubrication and driven by stepper motors. The seven gas filled cells are each pressure modulated by a 3 cm diameter, 0.3 cm stroke piston which is supported by diaphragm springs and driven electromagnetically at the system's mechanical resonant frequency. The mean pressure of the filling gas, which is the atmospheric constituent being measured, is changed by varying the temperature of a suitable molecular sieve.

  2. Insect flight on fluid interfaces: a chaotic interfacial oscillator

    NASA Astrophysics Data System (ADS)

    Mukundarajan, Haripriya; Prakash, Manu

    2013-11-01

    Flight is critical to the dominance of insect species on our planet, with about 98 percent of insect species having wings. How complex flight control systems developed in insects is unknown, and arboreal or aquatic origins have been hypothesized. We examine the biomechanics of aquatic origins of flight. We recently reported discovery of a novel mode of ``2D flight'' in Galerucella beetles, which skim along an air-water interface using flapping wing flight. This unique flight mode is characterized by a balance between capillary forces from the interface and biomechanical forces exerted by the flapping wings. Complex interactions on the fluid interface form capillary wave trains behind the insect, and produce vertical oscillations at the surface due to non-linear forces arising from deformation of the fluid meniscus. We present both experimental observations of 2D flight kinematics and a dynamic model explaining the observed phenomena. Careful examination of this interaction predicts the chaotic nature of interfacial flight and takeoff from the interface into airborne flight. The role of wingbeat frequency, stroke plane angle and body angle in determining transition between interfacial and fully airborne flight is highlighted, shedding light on the aquatic theory of flight evolution.

  3. Hydraulic involute cam actuator

    DOEpatents

    Love, Lonnie J [Knoxville, TN; Lind, Randall F [Loudon, TX

    2011-11-01

    Mechanical joints are provided in which the angle between a first coupled member and a second coupled member may be varied by mechanical actuators. In some embodiments the angle may be varied around a pivot axis in one plane and in some embodiments the angle may be varied around two pivot axes in two orthogonal planes. The joints typically utilize a cam assembly having two lobes with an involute surface. Actuators are configured to push against the lobes to vary the rotation angle between the first and second coupled member.

  4. How Insects Initiate Flight: Computational Analysis of a Damselfly in Takeoff Flight

    NASA Astrophysics Data System (ADS)

    Bode-Oke, Ayodeji; Zeyghami, Samane; Dong, Haibo; Flow Simulation Research Group Team

    2017-11-01

    Flight initiation is essential for survival in biological fliers and can be classified into jumping and non-jumping takeoffs. During jumping takeoffs, the legs generate most of the initial impulse. Whereas the wings generate most of the forces in non-jumping takeoffs, which are usually voluntary, slow, and stable. It is of interest to understand how non-jumping takeoffs occur and what strategies insects use to generate the required forces. Using a high fidelity computational fluid dynamics simulation, we identify the flow features and compute the wing aerodynamic forces to elucidate how flight forces are generated by a damselfly performing a non-jumping takeoff. Our results show that a damselfly generates about three times its bodyweight during the first half-stroke for liftoff while flapping through a steeply inclined stroke plane and slicing the air at high angles of attack. Consequently, a Leading Edge Vortex (LEV) is formed during both the downstroke and upstroke on all the four wings. The formation of the LEV, however, is inhibited in the subsequent upstrokes following takeoff. Accordingly, we observe a drastic reduction in the magnitude of the aerodynamic force, signifying the importance of LEV in augmenting force production. This work was supported by National Science Foundation [CBET-1313217] and Air Force Research Laboratory [FA9550-12-1-007].

  5. Novel Approach to Measuring the Droplet Detachment Force from Fibers.

    PubMed

    Amrei, M M; Venkateshan, D G; D'Souza, N; Atulasimha, J; Tafreshi, H Vahedi

    2016-12-20

    Determining the force required to detach a droplet from a fiber or from an assembly of fibers is of great importance to many applications. A novel technique is developed in this work to measure this force experimentally by using ferrofluid droplets in a magnetic field. Unlike previous methods reported in the literature, our technique does not require air flow or a mechanical object to detach the droplet from the fiber(s); therefore, it simplifies the experiment and also allows one to study the capillarity of the droplet-fiber system in a more isolated environment. In this article, we investigated the effects of the relative angle between intersecting fibers on the force required to detach a droplet from the fibers in the in-plane or out-of-plane direction. The in-plane and through-plane detachment forces were also predicted via numerical simulation and compared with the experimental results. Good agreement was observed between the numerical and experimental results. It was found that the relative angle between intersecting fibers has no significant effect on the detachment force in the out-of-plane direction. However, the detachment force in the in-plane direction depends strongly on the relative angle between the fibers, and it increases as this angle increases.

  6. The angle of inclination of the native ACL in the coronal and sagittal planes.

    PubMed

    Reid, Jonathan C; Yonke, Bret; Tompkins, Marc

    2017-04-01

    The purpose of this cross-sectional study was to evaluate the angle of inclination of the native anterior cruciate ligament (ACL) in both the sagittal and coronal planes and to evaluate these findings based on sex, height, BMI, and skeletal maturity. Inclusion criteria for the study included patients undergoing routine magnetic resonance imaging (MRI) of the knee at a single outpatient orthopedic center who had an intact ACL on MRI. Measurements of the angle of inclination were made on MRIs in both the sagittal and coronal planes. Patients were compared based on sex, height, BMI, and skeletal maturity. One-hundred and eighty-eight patients were included (36 skeletally immature/152 skeletally mature; 98 male/90 female). The overall angle of inclination was 74.3° ± 4.8° in the coronal plane and 46.9° ± 4.9° in the sagittal plane. Skeletally immature patients (coronal: 71.8° ± 6.1°; sagittal: 44.7° ± 5.5°) were significantly different in both coronal and sagittal planes (P = 0.04 and 0.01, respectively) from skeletally mature patients (coronal: 75.3° ± 4.7°; sagittal: 47.4° ± 4.7°). There were no differences based on sex, height, or BMI. There are differences between the angle of inclination findings in this study and other studies, which could be due to MRI and measurement techniques. Clinically, skeletal maturity may be important to account for when using the ACL angle of inclination to evaluate anatomic ACL reconstruction. Prognostic retrospective study, Level of evidence III.

  7. Measurement method for roll angular displacement with a high resolution by using diffraction gratings and a heterodyne interferometer

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

    Tang, Shanzhi, E-mail: shanzhit@gmail.com; School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049; Wang, Zhao

    The roll angle measurement is difficult to be achieved directly using a typical commercial interferometer due to its low sensitivity in axial direction, where the axial direction is orthogonal to the plane of the roll angular displacement. A roll angle measurement method combined diffraction gratings with a laser heterodyne interferometer is discussed in this paper. The diffraction grating placed in the plane of a roll angular displacement and the interferometer arranged in the plane's orthogonal direction, constitute the measurement pattern for the roll angle with high resolution. The roll angular displacement, considered as the linear, can be tested precisely whenmore » the corresponding angle is very small. Using the proposed method, the angle roll measurement obtains the high resolution of 0.002{sup ″}. Experiment has proved its feasibility and practicability.« less

  8. Measurement of passive ankle stiffness in subjects with chronic hemiparesis using a novel ankle robot

    PubMed Central

    Roy, Anindo; Bever, Christopher T.; Forrester, Larry W.; Macko, Richard F.; Hogan, Neville

    2011-01-01

    Our objective in this study was to assess passive mechanical stiffness in the ankle of chronic hemiparetic stroke survivors and to compare it with those of healthy young and older (age-matched) individuals. Given the importance of the ankle during locomotion, an accurate estimate of passive ankle stiffness would be valuable for locomotor rehabilitation, potentially providing a measure of recovery and a quantitative basis to design treatment protocols. Using a novel ankle robot, we characterized passive ankle stiffness both in sagittal and in frontal planes by applying perturbations to the ankle joint over the entire range of motion with subjects in a relaxed state. We found that passive stiffness of the affected ankle joint was significantly higher in chronic stroke survivors than in healthy adults of a similar cohort, both in the sagittal as well as frontal plane of movement, in three out of four directions tested with indistinguishable stiffness values in plantarflexion direction. Our findings are comparable to the literature, thus indicating its plausibility, and, to our knowledge, report for the first time passive stiffness in the frontal plane for persons with chronic stroke and older healthy adults. PMID:21346215

  9. A Study of Parallelism of the Occlusal Plane and Ala-Tragus Line

    PubMed Central

    Sadr, Katayoun; Sadr, Makan

    2009-01-01

    Background and aims Orientation of the occlusal plane is one of the most important clinical procedures in prostho-dontic rehabilitation of edentulous patients. The aim of this study was to define the best posterior reference point of ala-tragus line for orientation of occlusal plane for complete denture fabrication. Materials and methods Fifty-three dental students (27 females and 26 males) with complete natural dentition and Angel’s Class I occlusal relationship were selected. The subjects were photographed in natural head position while clenching on a Fox plane. After tracing the photographs, the angles between the following lines were measured: the occlusal plane (Fox plane) and the superior border of ala-tragus, the occlusal plane (Fox plane) and the middle of ala-tragus as well as the occlusal plane (Fox plane) and the inferior border of ala-tragus. Descriptive statistics, one sample t-test and independent t-test were used. P value less than 0.05 was considered significant. Results There was no parallelism between the occlusal plane and ala-tragus line with three different posterior ends and one sample t-test showed that the angles between them were significantly different from zero (p<0.05). However, the supe-rior border of ala-tragus line had the lowest mean angle, 1.80° (3.12) and was almost parallel to the occlusal plane. Conclusion The superior border of the tragus is suggested as the posterior reference for ala-tragus line. PMID:23230496

  10. A cephalometric study to determine the plane of occlusion in completely edentulous patients.

    PubMed

    Hindocha, Amit D; Vartak, Vikas N; Bhandari, Aruna J; Dudani, Mohit T

    2013-01-01

    Determination of the plane of occlusion in completely edentulous patients with the help of the ala-tragus line (Camper's plane) may be questioned. An attempt to devise an alternative method to determine the orientation of the plane of occlusion was made. Cephalometric analysis was used to identify whether a correlation exists between the plane of occlusion of dentulous Indian individuals and other stable cranial landmarks. A negative correlation was found to exist between the occlusal Plane-FH plane angle and the porion-nasion-anterior nasal spine (PoNANS) angle. From the derived mathematical correlation, it was concluded that the angulation of the occlusal plane in completely edentulous subjects may be determined by taking a cephalogram at the diagnostic stage. Further, the clinical applicability of the derived mathematical formula (while determining the plane of occlusion) was tested on completely edentulous patients.

  11. High precise measurement of tiny angle dimensional holes for the unit-holes of the LAMOST Focal Plane Plate

    NASA Astrophysics Data System (ADS)

    Zhou, Zengxiang; Jin, Yi; Zhai, Chao; Xing, Xiaozheng

    2008-07-01

    In the LAMOST project, the unit-holes on the Focal Plane Plate are the final installation location of the optical fiber positioning system. Theirs precision will influence the observation efficiency of the LAMOST. For the unique requirements, the unit-holes on the Focal Plane Plate are composed by a series of tiny angle dimensional holes which dimensional angle are between 16' to 2.5°. According to these requirements, the measurement of the tiny angle dimensional holes for the unit-holes needs to less than 3'. And all the unit-holes point to the virtual sphere center of the Focal Plane Plate. To that end, the angle departure of the unit-holes axis is changed to the distance from the virtual sphere center of Focal Plane Plate to the unit-holes axis. That is the better way to evaluate the technical requirements of the dimensional angle errors. In the measuring process, common measuring methods do not fit for the tiny angle dimensional hole by CMM(coordinate measurement machine). An extraordinary way to solve this problem is to insert a measuring stick into a unit-hole, with a target ball on the stick. Then measure the low point of the ball center and pull out the stick for the high station of center. Finally, calculate the two points for the unit-hole axis to get the angle departure. But on the other hand, use this methods will bring extra errors for the measuring stick and the target ball. For better analysis this question, a series experiments are mentioned in this paper, which testify that the influence of the measure implement is little. With increasing the distance between the low point and the high point position in the measuring process should enhance the accuracy of dimensional angle measurement.

  12. Influence of handrim wheelchair propulsion training in adolescent wheelchair users, a pilot study.

    PubMed

    Dysterheft, Jennifer L; Rice, Ian M; Rice, Laura A

    2015-01-01

    Ten full-time adolescent wheelchair users (ages 13-18) completed a total of three propulsion trials on carpet and tile surfaces, at a self-selected velocity, and on a concrete surface, at a controlled velocity. All trials were performed in their personal wheelchair with force and moment sensing wheels attached bilaterally. The first two trials on each surface were used as pre-intervention control trials. The third trial was performed after receiving training on proper propulsion technique. Peak resultant force, contact angle, stroke frequency, and velocity were recorded during all trials for primary analysis. Carpet and tile trials resulted in significant increases in contact angle and peak total force with decreased stroke frequency after training. During the velocity controlled trials on concrete, significant increases in contact angle occurred, as well as decreases in stroke frequency after training. Overall, the use of a training video and verbal feedback may help to improve short-term propulsion technique in adolescent wheelchair users and decrease the risk of developing upper limb pain and injury.

  13. Slope angle estimation method based on sparse subspace clustering for probe safe landing

    NASA Astrophysics Data System (ADS)

    Li, Haibo; Cao, Yunfeng; Ding, Meng; Zhuang, Likui

    2018-06-01

    To avoid planetary probes landing on steep slopes where they may slip or tip over, a new method of slope angle estimation based on sparse subspace clustering is proposed to improve accuracy. First, a coordinate system is defined and established to describe the measured data of light detection and ranging (LIDAR). Second, this data is processed and expressed with a sparse representation. Third, on this basis, the data is made to cluster to determine which subspace it belongs to. Fourth, eliminating outliers in subspace, the correct data points are used for the fitting planes. Finally, the vectors normal to the planes are obtained using the plane model, and the angle between the normal vectors is obtained through calculation. Based on the geometric relationship, this angle is equal in value to the slope angle. The proposed method was tested in a series of experiments. The experimental results show that this method can effectively estimate the slope angle, can overcome the influence of noise and obtain an exact slope angle. Compared with other methods, this method can minimize the measuring errors and further improve the estimation accuracy of the slope angle.

  14. In-Plane Anisotropic Photoconduction in Nonpolar Epitaxial a-Plane GaN.

    PubMed

    Pant, Rohit; Shetty, Arjun; Chandan, Greeshma; Roul, Basanta; Nanda, K K; Krupanidhi, S B

    2018-05-16

    Nonpolar a-plane GaN epitaxial films were grown on an r-plane sapphire using the plasma-assisted molecular beam epitaxy system, with various nitrogen plasma power conditions. The crystallinity of the films was characterized by high-resolution X-ray diffraction and reciprocal space mapping. Using the X-ray "rocking curve-phi scan", [0002], [1-100], and [1-102] azimuth angles were identified, and interdigitated electrodes along these directions were fabricated to evaluate the direction-dependent UV photoresponses. UV responsivity ( R) and internal gain ( G) were found to be dependent on the azimuth angle and in the order of [0002] > [1-102] > [1-100], which has been attributed to the enhanced crystallinity and lowest defect density along [0002] azimuth. The temporal response was very stable irrespective of growth conditions and azimuth angles. Importantly, response time, responsivity, and internal gain were 210 ms, 1.88 A W -1 , and 648.9%, respectively, even at a bias as low as 1 V. The results were validated using the Silvaco Atlas device simulator, and experimental observations were consistent with simulated results. Overall, the photoresponse is dependent on azimuth angles and requires further optimization, especially for materials with in-plane crystal anisotropy.

  15. Supersonic Shear Imaging Elastography in Skeletal Muscles: Relationship Between In Vivo and Synthetic Fiber Angles and Shear Modulus.

    PubMed

    Lima, Kelly; Rouffaud, Remi; Pereira, Wagner; Oliveira, Liliam F

    2018-04-30

    To verify a relationship between the pennation angle of synthetic fibers and muscle fibers with the shear modulus (μ) generated by Supersonic shear imaging (SSI) elastography and to compare the anisotropy of synthetic and in vivo pennate muscle fibers in the x 2 -x 3 plane (probe perpendicular to water surface or skin). First, the probe of Aixplorer ultrasound scanner (v.9, Supersonic Imagine, Aix-en-Provence, France) was placed in 2 positions (parallel [aligned] and transverse to the fibers) to test the anisotropy in the x 2 -x 3 plane. Subsequently, it was inclined (x 1 -x 3 plane) in relation to the fibers, forming 3 angles (18.25 °, 21.55 °, 36.86 °) for synthetic fibers and one (approximately 0 °) for muscle fibers. On the x 2 -x 3 plane, μ values of the synthetic and vastus lateralis fibers were significantly lower (P < .0001) at the transverse probe position than the longitudinal one. In the x 1 -x 3 plane, the μ values were significantly reduced (P < .0001) with the probe angle increasing, only for the synthetic fibers (approximately 0.90 kPa for each degree of pennation angle). The pennation angle was not related to the μ values generated by SSI elastography for the in vivo lateral head of the gastrocnemius and vastus lateralis muscles. However, a μ reduction with an angle increase in the synthetic fibers was observed. These findings contribute to increasing the applicability of SSI in distinct muscle architecture at normal or pathologic conditions. © 2018 by the American Institute of Ultrasound in Medicine.

  16. Effect of Outflow Graft Size on Flow in the Aortic Arch and Cerebral Blood Flow in Continuous Flow Pumps: Possible Relevance to Strokes.

    PubMed

    Bhat, Sindhoor; Mathew, Jayakala; Balakrishnan, Komrakshi R; Krishna Kumar, Ramarathnam

    One of the most devastating complications of continuous flow left ventricular devices (CFLVADS) is stroke, with a higher incidence in HeartWare Ventricular Assist Device (HVAD) as compared with HEARTMATE II. The reason for the observed difference in stroke rates is unclear. Because outflow graft diameters are different, we hypothesized that this could contribute to the difference in stroke rates. A computational fluid-structure interaction model was created from the computed tomography (CT) scan of a patient. Pressures were used as the boundary condition and the flow through the cerebral vessels was derived as outputs. Flow into the innominate artery was very sensitive to the anastomosis angle for a 10 mm as compared with a 14 mm graft, with the net innominate flow severely compromised with a 10 mm graft at 45° angle. Aortic insufficiency seems to affect cerebral blood flow nonlinearly with an 80% decrease at certain angles of outflow graft anastomosis. Arterial return in to the arch through a narrow graft has important jet effects and results in significant flow perturbations in the aortic arch and cerebral vessels and stasis. A 10 mm graft is more sensitive to angle of insertion than a 14 mm graft. Under some conditions, serious hypoperfusion of the innominate artery is possible. Aortic incompetence results in significant decrease of cerebral blood flow. No stasis was found in the pulsatile flow compared with LVAD flow.

  17. An articulated ankle-foot orthosis with adjustable plantarflexion resistance, dorsiflexion resistance and alignment: A pilot study on mechanical properties and effects on stroke hemiparetic gait

    PubMed Central

    Kobayashi, Toshiki; Orendurff, Michael S.; Hunt, Grace; Lincoln, Lucas S.; Gao, Fan; LeCursi, Nicholas; Foreman, K. Bo

    2017-01-01

    Mechanical properties of an articulated ankle-foot orthosis (AFO) are closely related to gait performance in individuals post-stroke. This paper presents a pilot study on the mechanical properties of a novel articulated AFO with adjustable plantarflexion resistance, dorsiflexion resistance and alignment, and its effect on ankle and knee joint kinematics and kinetics in an individual post-stroke during gait. The mechanical properties of the AFO were quantified. Gait analysis was performed using a 3D motion capture system with a split-belt instrumented treadmill under 12 different settings of the mechanical properties of the AFO [i.e. 4 plantarflexion resistances (P1

  18. The effect of changing plantarflexion resistive moment of an articulated ankle-foot orthosis on ankle and knee joint angles and moments while walking in patients post stroke

    PubMed Central

    Kobayashi, Toshiki; Singer, Madeline L.; Orendurff, Michael S.; Gao, Fan; Daly, Wayne K.; Foreman, K. Bo

    2015-01-01

    Background The adjustment of plantarflexion resistive moment of an articulated ankle-foot orthosis is considered important in patients post stroke, but the evidence is still limited. Therefore, the aim of this study was to investigate the effect of changing the plantarflexion resistive moment of an articulated ankle-foot orthosis on ankle and knee joint angles and moments in patients post stroke. Methods Gait analysis was performed on 10 subjects post stroke under four different plantarflexion resistive moment conditions using a newly designed articulated ankle-foot orthosis. Data were recorded using a Bertec split-belt instrumented treadmill in a 3-dimensional motion analysis laboratory. Findings The ankle and knee sagittal joint angles and moments were significantly affected by the amount of plantarflexion resistive moment of the ankle-foot orthosis. Increasing the plantarflexion resistive moment of the ankle-foot orthosis induced significant decreases both in the peak ankle plantarflexion angle (P<0.01) and the peak knee extension angle (P<0.05). Also, the increase induced significant increases in the internal dorsiflexion moment of the ankle joint (P<0.01) and significantly decreased the internal flexion moment of the knee joint (P<0.01). Interpretation These results suggest an important link between the kinematic/kinetic parameters of the lower-limb joints and the plantarflexion resistive moment of an articulated ankle-foot orthosis. A future study should be performed to clarify their relationship further so that the practitioners may be able to use these parameters as objective data to determine an optimal plantarflexion resistive moment of an articulated ankle-foot orthosis for improved orthotic care in individual patients. PMID:26149007

  19. The effect of changing plantarflexion resistive moment of an articulated ankle-foot orthosis on ankle and knee joint angles and moments while walking in patients post stroke.

    PubMed

    Kobayashi, Toshiki; Singer, Madeline L; Orendurff, Michael S; Gao, Fan; Daly, Wayne K; Foreman, K Bo

    2015-10-01

    The adjustment of plantarflexion resistive moment of an articulated ankle-foot orthosis is considered important in patients post stroke, but the evidence is still limited. Therefore, the aim of this study was to investigate the effect of changing the plantarflexion resistive moment of an articulated ankle-foot orthosis on ankle and knee joint angles and moments in patients post stroke. Gait analysis was performed on 10 subjects post stroke under four different plantarflexion resistive moment conditions using a newly designed articulated ankle-foot orthosis. Data were recorded using a Bertec split-belt instrumented treadmill in a 3-dimensional motion analysis laboratory. The ankle and knee sagittal joint angles and moments were significantly affected by the amount of plantarflexion resistive moment of the ankle-foot orthosis. Increasing the plantarflexion resistive moment of the ankle-foot orthosis induced significant decreases both in the peak ankle plantarflexion angle (P<0.01) and the peak knee extension angle (P<0.05). Also, the increase induced significant increases in the internal dorsiflexion moment of the ankle joint (P<0.01) and significantly decreased the internal flexion moment of the knee joint (P<0.01). These results suggest an important link between the kinematic/kinetic parameters of the lower-limb joints and the plantarflexion resistive moment of an articulated ankle-foot orthosis. A future study should be performed to clarify their relationship further so that the practitioners may be able to use these parameters as objective data to determine an optimal plantarflexion resistive moment of an articulated ankle-foot orthosis for improved orthotic care in individual patients. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Kinematic functions for the 7 DOF robotics research arm

    NASA Technical Reports Server (NTRS)

    Kreutz, K.; Long, M.; Seraji, Homayoun

    1989-01-01

    The Robotics Research Model K-1207 manipulator is a redundant 7R serial link arm with offsets at all joints. To uniquely determine joint angles for a given end-effector configuration, the redundancy is parameterized by a scalar variable which corresponds to the angle between the manipulator elbow plane and the vertical plane. The forward kinematic mappings from joint-space to end-effector configuration and elbow angle, and the augmented Jacobian matrix which gives end-effector and elbow angle rates as a function of joint rates, are also derived.

  1. An ultra-high vacuum chamber for scattering experiments featuring in-vacuum continuous in-plane variation of the angle between entrance and exit vacuum ports

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

    Englund, Carl-Johan; Agåker, Marcus, E-mail: marcus.agaker@physics.uu.se; Fredriksson, Pierre

    2015-09-15

    A concept that enables in-vacuum continuous variation of the angle between two ports in one plane has been developed and implemented. The vacuum chamber allows for measuring scattering cross sections as a function of scattering angle and is intended for resonant inelastic X-ray scattering experiments. The angle between the ports can be varied in the range of 30°-150°, while the pressure change is less than 2 × 10{sup −10} mbars.

  2. Esthetic smile preferences and the orientation of the maxillary occlusal plane.

    PubMed

    Kattadiyil, Mathew T; Goodacre, Charles J; Naylor, W Patrick; Maveli, Thomas C

    2012-12-01

    The anteroposterior orientation of the maxillary occlusal plane has an important role in the creation, assessment, and perception of an esthetic smile. However, the effect of the angle at which this plane is visualized (the viewing angle) in a broad smile has not been quantified. The purpose of this study was to assess the esthetic preferences of dental professionals and nondentists by using 3 viewing angles of the anteroposterior orientation of the maxillary occlusal plane. After Institutional Review Board approval, standardized digital photographic images of the smiles of 100 participants were recorded by simultaneously triggering 3 cameras set at different viewing angles. The top camera was positioned 10 degrees above the occlusal plane (camera #1, Top view); the center camera was positioned at the level of the occlusal plane (camera #2, Center view); and the bottom camera was located 10 degrees below the occlusal plane (camera #3, Bottom view). Forty-two dental professionals and 31 nondentists (persons from the general population) independently evaluated digital images of each participant's smile captured from the Top view, Center view, and Bottom view. The 73 evaluators were asked individually through a questionnaire to rank the 3 photographic images of each patient as 'most pleasing,' 'somewhat pleasing,' or 'least pleasing,' with most pleasing being the most esthetic view and the preferred orientation of the occlusal plane. The resulting esthetic preferences were statistically analyzed by using the Friedman test. In addition, the participants were asked to rank their own images from the 3 viewing angles as 'most pleasing,' 'somewhat pleasing,' and 'least pleasing.' The 73 evaluators found statistically significant differences in the esthetic preferences between the Top and Bottom views and between the Center and Bottom views (P<.001). No significant differences were found between the Top and Center views. The Top position was marginally preferred over the Center, and both were significantly preferred over the Bottom position. When the participants evaluated their own smiles, a significantly greater number (P< .001) preferred the Top view over the Center or the Bottom views. No significant differences were found in preferences based on the demographics of the evaluators when comparing age, education, gender, profession, and race. The esthetic preference for the maxillary occlusal plane was influenced by the viewing angle with the higher (Top) and center views preferred by both dental and nondental evaluators. The participants themselves preferred the higher view of their smile significantly more often than the center or lower angle views (P<.001). Copyright © 2012 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

  3. The Effect of Pitching Phase on the Vortex Circulation for a Flapping Wing During Stroke Reversal

    NASA Astrophysics Data System (ADS)

    Burge, Matthew; Ringuette, Matthew

    2017-11-01

    We study the effect of pitching-phase on the circulation behavior for the 3D flow structures produced during stroke reversal for a 2-degree-of-freedom flapping wing executing hovering kinematics. Previous research has related the choice in pitching-phase with respect to the wing rotation during stroke reversal (advanced vs. symmetric pitch-timing) to a lift peak preceding stroke reversal. However, results from experiments on the time-varying circulation contributions from the 3D vortex structures across the span produced by both rotation and pitching are lacking. The objective of this research is to quantitatively examine how the spanwise circulation of these structures is affected by the pitching-phase for several reduced pitching frequencies. We employ a scaled wing model in a glycerin-water mixture and measure the time-varying velocity using multiple planes of stereo digital particle image velocimetry. Data-plane positions along the wing span are informed by the unsteady behavior of the 3D vortex structures found in our prior flow visualization movies. Individual vortices are identified to calculate their circulation. This work is aimed at understanding how the behavior of the vortex structures created during stroke reversal vary with key motion parameters. This work is supported by the National Science Foundation, Award Number 1336548, supervised by Dr. Ronald Joslin.

  4. Pilot study of a robotic protocol to treat shoulder subluxation in patients with chronic stroke

    PubMed Central

    2013-01-01

    Background Shoulder subluxation is a frequent complication of motor impairment after stroke, leading to soft tissue damage, stretching of the joint capsule, rotator cuff injury, and in some cases pain, thus limiting use of the affected extremity beyond weakness. In this pilot study, we determined whether robotic treatment of chronic shoulder subluxation can lead to functional improvement and whether any improvement was robust. Methods 18 patients with chronic stroke (3.9 ± 2.9 years from acute stroke), completed 6 weeks of robotic training using the linear shoulder robot. Training was performed 3 times per week on alternate days. Each session consisted of 3 sets of 320 repetitions of the affected arm, and the robotic protocol alternated between training vertical arm movements, shoulder flexion and extension, in an anti-gravity plane, and training horizontal arm movements, scapular protraction and retraction, in a gravity eliminated plane. Results Training with the linear robot improved shoulder stability, motor power, and resulted in improved functional outcomes that were robust 3 months after training. Conclusion In this uncontrolled pilot study, the robotic protocol effectively treated shoulder subluxation in chronic stroke patients. Treatment of subluxation can lead to improved functional use of the affected arm, likely by increasing motor power in the trained muscles. PMID:23914834

  5. Pilot study of a robotic protocol to treat shoulder subluxation in patients with chronic stroke.

    PubMed

    Dohle, Carolin I; Rykman, Avrielle; Chang, Johanna; Volpe, Bruce T

    2013-08-05

    Shoulder subluxation is a frequent complication of motor impairment after stroke, leading to soft tissue damage, stretching of the joint capsule, rotator cuff injury, and in some cases pain, thus limiting use of the affected extremity beyond weakness. In this pilot study, we determined whether robotic treatment of chronic shoulder subluxation can lead to functional improvement and whether any improvement was robust. 18 patients with chronic stroke (3.9 ± 2.9 years from acute stroke), completed 6 weeks of robotic training using the linear shoulder robot. Training was performed 3 times per week on alternate days. Each session consisted of 3 sets of 320 repetitions of the affected arm, and the robotic protocol alternated between training vertical arm movements, shoulder flexion and extension, in an anti-gravity plane, and training horizontal arm movements, scapular protraction and retraction, in a gravity eliminated plane. Training with the linear robot improved shoulder stability, motor power, and resulted in improved functional outcomes that were robust 3 months after training. In this uncontrolled pilot study, the robotic protocol effectively treated shoulder subluxation in chronic stroke patients. Treatment of subluxation can lead to improved functional use of the affected arm, likely by increasing motor power in the trained muscles.

  6. Quantitative characterization of spin-orbit torques in Pt/Co/Pt/Co/Ta/BTO heterostructures due to the magnetization azimuthal angle dependence

    NASA Astrophysics Data System (ADS)

    Engel, Christian; Goolaup, Sarjoosing; Luo, Feilong; Lew, Wen Siang

    2017-08-01

    Substantial understanding of spin-orbit interactions in heavy-metal (HM)/ferromagnet (FM) heterostructures is crucial in developing spin-orbit torque (SOT) spintronics devices utilizing spin Hall and Rashba effects. Though the study of SOT effective field dependence on the out-of-plane magnetization angle has been relatively extensive, the understanding of in-plane magnetization angle dependence remains unknown. Here, we analytically propose a method to compute the SOT effective fields as a function of the in-plane magnetization angle using the harmonic Hall technique in perpendicular magnetic anisotropy (PMA) structures. Two different samples with PMA, a Pt /Co /Pt /Co /Ta /BaTi O3 (BTO) test sample and a Pt/Co/Pt/Co/Ta reference sample, are studied using the derived formula. Our measurements reveal that only the dampinglike field of the test sample with a BTO capping layer exhibits an in-plane magnetization angle dependence, while no angular dependence is found in the reference sample. The presence of the BTO layer in the test sample, which gives rise to a Rashba effect at the interface, is ascribed as the source of the angular dependence of the dampinglike field.

  7. 40 MHz high-frequency ultrafast ultrasound imaging.

    PubMed

    Huang, Chih-Chung; Chen, Pei-Yu; Peng, Po-Hsun; Lee, Po-Yang

    2017-06-01

    Ultrafast high-frame-rate ultrasound imaging based on coherent-plane-wave compounding has been developed for many biomedical applications. Most coherent-plane-wave compounding systems typically operate at 3-15 MHz, and the image resolution for this frequency range is not sufficient for visualizing microstructure tissues. Therefore, the purpose of this study was to implement a high-frequency ultrafast ultrasound imaging operating at 40 MHz. The plane-wave compounding imaging and conventional multifocus B-mode imaging were performed using the Field II toolbox of MATLAB in simulation study. In experiments, plane-wave compounding images were obtained from a 256 channel ultrasound research platform with a 40 MHz array transducer. All images were produced by point-spread functions and cyst phantoms. The in vivo experiment was performed from zebrafish. Since high-frequency ultrasound exhibits a lower penetration, chirp excitation was applied to increase the imaging depth in simulation. The simulation results showed that a lateral resolution of up to 66.93 μm and a contrast of up to 56.41 dB were achieved when using 75-angles plane waves in compounding imaging. The experimental results showed that a lateral resolution of up to 74.83 μm and a contrast of up to 44.62 dB were achieved when using 75-angles plane waves in compounding imaging. The dead zone and compounding noise are about 1.2 mm and 2.0 mm in depth for experimental compounding imaging, respectively. The structure of zebrafish heart was observed clearly using plane-wave compounding imaging. The use of fewer than 23 angles for compounding allowed a frame rate higher than 1000 frames per second. However, the compounding imaging exhibits a similar lateral resolution of about 72 μm as the angle of plane wave is higher than 10 angles. This study shows the highest operational frequency for ultrafast high-frame-rate ultrasound imaging. © 2017 American Association of Physicists in Medicine.

  8. Comparing trapezius muscle activity in the different planes of shoulder elevation

    PubMed Central

    Ishigaki, Tomonobu; Ishida, Tomoya; Samukawa, Mina; Saito, Hiroshi; Hirokawa, Motoki; Ezawa, Yuya; Sugawara, Makoto; Tohyama, Harukazu; Yamanaka, Masanori

    2015-01-01

    [Purpose] The purpose of this study was to compare the upper, middle, and lower trapezius muscles’ activity in the different planes of shoulder elevation. [Subjects] Twenty male subjects volunteered for this study. [Methods] Surface electromyographic (EMG) activity for each of the three regions of the trapezius muscles in the three different planes of elevation were collected while the participants maintained 30, 60, and 90 degrees of elevation in each plane. The EMG data were normalized with maximum voluntary isometric contraction (%MVIC), and compared among the planes at each angle of elevation. [Results] There were significantly different muscle activities among the elevation planes at each angle. [Conclusion] This study found that the three regions of the trapezius muscles changed their activity depending on the planes of shoulder elevation. These changes in the trapezius muscles could induce appropriate scapular motion to face the glenoid cavity in the correct directions in different planes of shoulder elevation. PMID:26157248

  9. Comparing trapezius muscle activity in the different planes of shoulder elevation.

    PubMed

    Ishigaki, Tomonobu; Ishida, Tomoya; Samukawa, Mina; Saito, Hiroshi; Hirokawa, Motoki; Ezawa, Yuya; Sugawara, Makoto; Tohyama, Harukazu; Yamanaka, Masanori

    2015-05-01

    [Purpose] The purpose of this study was to compare the upper, middle, and lower trapezius muscles' activity in the different planes of shoulder elevation. [Subjects] Twenty male subjects volunteered for this study. [Methods] Surface electromyographic (EMG) activity for each of the three regions of the trapezius muscles in the three different planes of elevation were collected while the participants maintained 30, 60, and 90 degrees of elevation in each plane. The EMG data were normalized with maximum voluntary isometric contraction (%MVIC), and compared among the planes at each angle of elevation. [Results] There were significantly different muscle activities among the elevation planes at each angle. [Conclusion] This study found that the three regions of the trapezius muscles changed their activity depending on the planes of shoulder elevation. These changes in the trapezius muscles could induce appropriate scapular motion to face the glenoid cavity in the correct directions in different planes of shoulder elevation.

  10. Expressions for the Total Yaw Angle

    DTIC Science & Technology

    2016-09-01

    1. Introduction 1 2. Mathematical Notation 1 3. Total Yaw Expression Derivations 2 3.1 First Derivation 2 3.2 Second Derivation 4 3.3 Other...4 iv Approved for public release; distribution is unlimited. 1. Introduction The total yaw angle, γt , of a ballistic projectile is... elevation angles from spherical coordinates.∗ We again place point A at the end point of V. Now imagine a plane parallel to the y-z plane that includes

  11. Triple differential cross-sections of Ne (2s2) in coplanar to perpendicular plane geometry

    NASA Astrophysics Data System (ADS)

    Chen, L. Q.; Khajuria, Y.; Chen, X. J.; Xu, K. Z.

    2003-10-01

    The distorted wave Born approximation (DWBA) with the spin averaged static exchange potential has been used to calculate the triple differential cross-sections (TDCSs) for Ne (2s^2) ionization by electron impact in coplanar to perpendicular plane symmetric geometry at 110.5 eV incident electron energy. The present theoretical results at gun angles Psi = 0^circ (coplanar symmetric geometry) and Psi = 90^circ (perpendicular plane geometry) are in satisfactory agreement with the available experimental data. A deep interference minimum appears in the TDCS in the coplanar symmetric geometry and a strong peak at scattering angle xi = 90^circ caused by the single collision mechanism has been observed in the perpendicular plane geometry. The TDCSs at the gun angles Psi = 30^circ, and Psi = 60^circ are predicted.

  12. Broadening of resistive transition and irreversibility line for epitaxial YBa2Cu3O7-δ thin film

    NASA Astrophysics Data System (ADS)

    Xiao-jun, Xu; Ke-bin, Li; Jun, Fang; Zhi-he, Wang; Xiao-wen, Cao

    1996-04-01

    The broadening of resistive transition of c axis oriented epitaxial YBCO thin film has been measured for three configurations: (1) Hparc and H ⊥ I; (2) Hparab plane and H ⊥ I; (3) Hparab plane and HparI in magnetic field up to 8 Tesla(T), and for different angle θ of magnetic field relative to the ab plane with H = 4T. The results obtained indicate that the broadening of resistive transition is mainly determined by the angle θ, but is hardly related to the angle α made between magnetic field and tran sport current in ab plane. This means that the broadening of resistive transition is not determined by flux motion drived by apparent Lorentz force. An expression of angular dependence of irreversibility line has been given.

  13. Sonographic investigation of anatomical specimens of infant hip joints.

    PubMed

    Falliner, Axel; Hahne, Hans-Jürgen; Hassenpflug, Joachim

    2002-07-01

    The anatomical foundations of infant hip sonography techniques are ill-defined. We investigated anatomical specimens of infant hip joints in a water bath, with Graf's and Terjesen's methods. Acetabular position was varied in defined increments, with respect to the ultrasound beam. The alpha angles and the femoral head coverage were measured. Plastic acetabular casts were sawn along the sonographic section planes, and the cut sections compared with the sonographic sections. For images to be obtained, which were analysable by the two methods, the ultrasound beam had to intersect with the acetabular inlet plane at defined angles. The acetabular notch had to be anteriorly rotated from the ultrasound beam plane by at least 20 degrees. Beam entry within a 50 degrees sector posterior to the perpendicular on the inlet plane gave analysable images. The alpha angles and femoral head coverage were much affected by coronal-plane transducer tilt. Caudad tilts were associated with lesser values, a fact that should be borne in mind in clinical ultrasound investigations.

  14. Orientational Dynamics of a Functionalized Alkyl Planar Monolayer Probed by Polarization-Selective Angle-Resolved Infrared Pump-Probe Spectroscopy.

    PubMed

    Nishida, Jun; Yan, Chang; Fayer, Michael D

    2016-10-12

    Polarization-selective angle-resolved infrared pump-probe spectroscopy was developed and used to study the orientational dynamics of a planar alkylsiloxane monolayer functionalized with a rhenium metal carbonyl headgroup on an SiO 2 surface. The technique, together with a time-averaged infrared linear dichroism measurement, characterized picosecond orientational relaxation of the headgroup occurring at the monolayer-air interface by employing several sets of incident angles of the infrared pulses relative to the sample surface. By application of this method and using a recently developed theory, it was possible to extract both the out-of-plane and "mainly"-in-plane orientational correlation functions in a model-independent manner. The observed correlation functions were compared with theoretically derived correlation functions based on several dynamical models. The out-of-plane correlation function reveals the highly restricted out-of-plane motions of the head groups and also suggests that the angular distribution of the transition dipole moments is bimodal. The mainly-in-plane correlation function, for the sample studied here with the strongly restricted out-of-plane motions, essentially arises from the purely in-plane dynamics. In contrast to the out-of-plane dynamics, significant in-plane motions occurring over various time scales were observed including an inertial motion, a restricted wobbling motion of ∼3 ps, and complete randomization occurring in ∼25 ps.

  15. Selective activation of the latissimus dorsi and the inferior fibers of trapezius at various shoulder angles during isometric pull-down exertion.

    PubMed

    Park, Se-yeon; Yoo, Won-gyu

    2013-12-01

    The aim of this study was to determine the effect of isometric pull down exercise on muscle activity with shoulder elevation angles of 60°, 90°, and 120° and sagittal, scapular, and frontal movement planes, by electromyography (EMG) of the latissimus dorsi, inferior fibers of trapezius, and latissimus dorsi/inferior fibers of trapezius activity ratio. Fourteen men performed nine conditions of isometric pull down exercise (three conditions of shoulder elevation × three conditions of movement planes). Surface EMG was used to collect data from the latissimus dorsi and inferior fibers of trapezius during exercise. Two-way repeated analysis of variance with two within-subject factors (shoulder elevation angles and planes of movement) was used to determine the significance of the latissimus dorsi and inferior fibers of trapezius activity and latissimus dorsi/inferior fibers of trapezius activity ratio. The latissimus dorsi activity and ratio between the latissimus dorsi and the inferior fibers of trapezius were significantly decreased as shoulder elevation angle increased from 60° to 120°. The inferior fibers of trapezius activity was significantly increased with shoulder elevation angle. The EMG activity and the ratios were not affected by changes in movement planes. This study suggests that selective activation of the latissimus dorsi is accomplished with a low shoulder elevation angle, while the inferior fibers of the trapezius are activated with high shoulder elevation angles. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. [Evaluation of the resolving power of different angles in MPR images of 16DAS-MDCT].

    PubMed

    Kimura, Mikio; Usui, Junshi; Nozawa, Takeo

    2007-03-20

    In this study, we evaluated the resolving power of three-dimensional (3D) multiplanar reformation (MPR) images with various angles by using 16 data acquisition system multi detector row computed tomography (16DAS-MDCT) . We reconstructed the MPR images using data with a 0.75 mm slice thickness of the axial image in this examination. To evaluate resolving power, we used an original new phantom (RC phantom) that can be positioned at any slice angle in MPR images. We measured the modulation transfer function (MTF) by using the methods of measuring pre-sampling MTF, and used Fourier transform of image data of the square wave chart. The scan condition and image reconstruction condition that were adopted in this study correspond to the condition that we use for three-dimensional computed tomographic angiography (3D-CTA) examination of the head in our hospital. The MTF of MPR images showed minimum values at slice angles in parallel with the axial slice, and showed maximum values at the sagittal slice and coronal slice angles that are parallel to the Z-axis. With an oblique MPR image, MTF did not change with angle changes in the oblique sagittal slice plane, but in the oblique coronal slice plane, MTF increased as the tilt angle increased from the axial plane to the Z plane. As a result, we could evaluate the resolving power of a head 3D image by measuring the MTF of the axial image and sagittal image or the coronal image.

  17. A DYNAMIC VALGUS INDEX THAT COMBINES HIP AND KNEE ANGLES: ASSESSMENT OF UTILITY IN FEMALES WITH PATELLOFEMORAL PAIN.

    PubMed

    Scholtes, Sara A; Salsich, Gretchen B

    2017-06-01

    Two=dimensional motion analysis of lower=extremity movement typically focuses on the knee frontal plane projection angle, which considers the position of the femur and the tibia. A measure that includes the pelvis may provide a more comprehensive and accurate indicator of lower=extremity movement. Hypothesis/Purpose: The purpose of the study was to describe the utility of a two=dimensional dynamic valgus index (DVI) in females with patellofemoral pain. The hypothesis was that the DVI would be more reliable and valid than the knee frontal plane projection angle, be greater in females with patellofemoral pain during a single=limb squat than in females without patellofemoral pain, and decrease in females with patellofemoral pain following instruction. Study Design: Controlled Laboratory Study. Data were captured while participants performed single limb squats under two conditions: usual and corrected. Two=dimensional hip and knee angles and a DVI that combined the hip and knee angles were calculated. Three=dimensional sagittal, frontal, and transverse plane angles of the hip and knee and a DVI combining the frontal and transverse plane angles were calculated. The two=dimensional DVI demonstrated moderate reliability (ICC=0.74). The correlation between the two=dimensional and three=dimensional DVI's was 0.635 (p<0001). Females with patellofemoral pain demonstrated a greater two=dimensional DVI (31.14 °±13.36 °) than females without patellofemoral pain (18.30 °±14.97 °; p=0.010). Females with patellofemoral pain demonstrated a decreased DVI in the corrected (19.04 °±13.70 °) versus usual (31.14 °±13.36 °) condition (p=0.001). The DVI is a reliable and valid measure that may provide a more comprehensive assessment of lower=extremity movement patterns than the knee frontal plane projection angle in individuals with lower=extremity musculoskeletal pain problems. 2b.

  18. Hummingbird flight stability and control in freestream turbulent winds.

    PubMed

    Ravi, Sridhar; Crall, James D; McNeilly, Lucas; Gagliardi, Susan F; Biewener, Andrew A; Combes, Stacey A

    2015-05-01

    Airflow conditions close to the Earth's surface are often complex, posing challenges to flight stability and control for volant taxa. Relatively little is known about how well flying animals can contend with complex, adverse air flows, or about the flight control mechanisms used by animals to mitigate wind disturbances. Several recent studies have examined flight in the unsteady von Kármán vortex streets that form behind cylinders, generating flow disturbances that are predictable in space and time; these structures are relatively rare in nature, because they occur only the immediate, downstream vicinity of an object. In contrast, freestream turbulence is characterized by rapid, unpredictable flow disturbances across a wide range of spatial and temporal scales, and is nearly ubiquitous in natural habitats. Hummingbirds are ideal organisms for studying the influence of freestream turbulence on flight, as they forage in a variety of aerial conditions and are powerful flyers. We filmed ruby-throated hummingbirds (Archilochus colubris) maintaining position at a feeder in laminar and strongly turbulent (intensity ∼15%) airflow environments within a wind tunnel and compared their mean kinematics of the head, body, tail and wing, as well as variability in these parameters. Hummingbirds exhibited remarkably stable head position and orientation in both smooth and turbulent flow while maintaining position at the feeder. However, the hummingbird's body was less stable in turbulent flow and appeared to be most sensitive to disturbances along the mediolateral axis, displaying large lateral accelerations, translations and rolling motions during flight. The hummingbirds mitigated these disturbances by increasing mean wing stroke amplitude and stroke plane angle, and by varying these parameters asymmetrically between the wings and from one stroke to the next. They also actively varied the orientation and fan angle of the tail, maintaining a larger mean fan angle when flying in turbulent flow; this may improve their passive stability, but probably incurs an energetic cost as a result of increased drag. Overall, we observed many of the same kinematic changes noted previously for hummingbirds flying in a von Kármán vortex street, but we also observed kinematic changes associated with high force production, similar to those seen during load-lifting or high-speed flight. These findings suggest that flight may be particularly costly in fully mixed, freestream turbulence, which is the flow condition that hummingbirds are likely to encounter most frequently in natural habitats. © 2015. Published by The Company of Biologists Ltd.

  19. Tip-path-plane angle effects on rotor blade-vortex interaction noise levels and directivity

    NASA Technical Reports Server (NTRS)

    Burley, Casey L.; Martin, Ruth M.

    1988-01-01

    Acoustic data of a scale model BO-105 main rotor acquired in a large aeroacoustic wind tunnel are presented to investigate the parametric effects of rotor operating conditions on blade-vortex interaction (BVI) impulsive noise. Contours of a BVI noise metric are employed to quantify the effects of rotor advance ratio and tip-path-plane angle on BVI noise directivity and amplitude. Acoustic time history data are presented to illustrate the variations in impulsive characteristics. The directionality, noise levels and impulsive content of both advancing and retreating side BVI are shown to vary significantly with tip-path-plane angle and advance ratio over the range of low and moderate flight speeds considered.

  20. Predictors of favorable soft tissue profile outcomes following Class II Twin-block treatment.

    PubMed

    Kim, Ji-Eun; Mah, Su-Jung; Kim, Tae-Woo; Kim, Su-Jung; Park, Ki-Ho; Kang, Yoon-Goo

    2018-01-01

    The aim of this study was to determine cephalometric factors that help predict favorable soft-tissue profile outcomes following treatment with the Class II Twin-block appliance. Pre- and post-treatment lateral cephalograms of 45 patients treated with the Class II Twin-block appliance were retrospectively analyzed. Profile silhouettes were drawn from the cephalograms and evaluated by three orthodontists in order to determine the extent of improvement. Samples were divided into a favorable group (upper 30% of visual analogue scale [VAS] scores, n = 14) and an unfavorable group (lower 30% of VAS scores, n = 14). Skeletal and soft-tissue measurements were performed on the cephalograms and an intergroup comparison was conducted. An independent t -test revealed that the following pre-treatment values were lower in the favorable group compared to the unfavorable group: lower incisor to mandibular plane angle, lower incisor to pogonion distance, point A-nasion-point B angle, sella-nasion line (SN) to maxillary plane angle, SN to mandibular plane angle, gonial angle, and symphysis inclination. The favorable group had a larger incisor inclination to occlusal plane. Moreover, the favorable group showed larger post-treatment changes in gonial angle, B point projection, and pogonion projection than did the unfavorable group. Class II malocclusion patients with a low divergent skeletal pattern and reduced lower incisor protrusions are likely to show more improvement in soft-tissue profile outcomes following Class II Twin-block treatment.

  1. METHODOLOGICAL NOTES: Rotation of the swing plane of Foucault's pendulum and Thomas spin precession: two sides of one coin

    NASA Astrophysics Data System (ADS)

    Krivoruchenko, Mikhail I.

    2009-08-01

    Using elementary geometric tools, we apply essentially the same methods to derive expressions for the rotation angle of the swing plane of Foucault's pendulum and the rotation angle of the spin of a relativistic particle moving in a circular orbit (the Thomas precession effect).

  2. 14 CFR 25.1387 - Position light system dihedral angles.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the airplane, and the other at 110 degrees to the left of the first... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

  3. 14 CFR 27.1387 - Position light system dihedral angles.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the rotorcraft, and the other at 110 degrees to the left of the first... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

  4. 14 CFR 27.1387 - Position light system dihedral angles.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the rotorcraft, and the other at 110 degrees to the left of the first... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

  5. 14 CFR 27.1387 - Position light system dihedral angles.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the rotorcraft, and the other at 110 degrees to the left of the first... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

  6. 14 CFR 29.1387 - Position light system dihedral angles.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... described in this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the rotorcraft, and the other at 110 degrees to the left of... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

  7. 14 CFR 23.1387 - Position light system dihedral angles.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... described in this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the airplane, and the other at 110 degrees to the left of the... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

  8. 14 CFR 25.1387 - Position light system dihedral angles.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the airplane, and the other at 110 degrees to the left of the first... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

  9. 14 CFR 23.1387 - Position light system dihedral angles.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... described in this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the airplane, and the other at 110 degrees to the left of the... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

  10. 14 CFR 25.1387 - Position light system dihedral angles.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the airplane, and the other at 110 degrees to the left of the first... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

  11. 14 CFR 27.1387 - Position light system dihedral angles.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the rotorcraft, and the other at 110 degrees to the left of the first... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

  12. 14 CFR 29.1387 - Position light system dihedral angles.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... described in this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the rotorcraft, and the other at 110 degrees to the left of... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

  13. 14 CFR 25.1387 - Position light system dihedral angles.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the airplane, and the other at 110 degrees to the left of the first... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

  14. 14 CFR 29.1387 - Position light system dihedral angles.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... described in this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the rotorcraft, and the other at 110 degrees to the left of... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

  15. 14 CFR 23.1387 - Position light system dihedral angles.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... described in this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the airplane, and the other at 110 degrees to the left of the... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

  16. 14 CFR 23.1387 - Position light system dihedral angles.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... described in this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the airplane, and the other at 110 degrees to the left of the... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

  17. 14 CFR 29.1387 - Position light system dihedral angles.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... described in this section. (b) Dihedral angle L (left) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of the rotorcraft, and the other at 110 degrees to the left of... degrees to the right and to the left, respectively, to a vertical plane passing through the longitudinal...

  18. Cross-Grain Knife Planing Improves Surface Quality and Utilization of Aspen

    Treesearch

    Harold A. Stewart

    1971-01-01

    Aspen at 6 percent moisture content was planed parallel to the grain and across the grain on a cabinet planer with a 25? rake angle, 1/16- and 1/32-inch depth of cut, and 20 knife marks per inch. Aspen was also cross-grain knife planed with a 45? rake angle, 1/32-, 1/16-, and 1/8-inch depths of cut, and 20, 10, 5, and 2.5 knife marks per inch. Cross-grain knife...

  19. Exciting surface plasmon polaritons in the Kretschmann configuration by a light beam

    NASA Astrophysics Data System (ADS)

    Vinogradov, A. P.; Dorofeenko, A. V.; Pukhov, A. A.; Lisyansky, A. A.

    2018-06-01

    We consider exciting surface plasmon polaritons in the Kretschmann configuration. Contrary to common belief, we show that a plane-wave incident at an angle greater than the angle of total internal reflection does not excite surface plasmon polaritons. These excitations do arise, however, if the incident light forms a narrow beam composed of an infinite number of plane waves. The surface plasmon polariton is formed at the geometrical edge of the beam as a result of interference of reflected plane waves.

  20. The effects of engine speed and injection characteristics on the flow field and fuel/air mixing in motored two-stroke diesel engines

    NASA Technical Reports Server (NTRS)

    Nguyen, H. L.; Carpenter, M. H.; Ramos, J. I.

    1987-01-01

    A numerical analysis is presented on the effects of the engine speed, injection angle, droplet distribution function, and spray cone angle on the flow field, spray penetration and vaporization, and turbulence in a turbocharged motored two-stroke diesel engine. The results indicate that the spray penetration and vaporization, velocity, and turbulence kinetic energy increase with the intake swirl angle. Good spray penetration, vaporization, and mixing can be achieved by injecting droplets of diameters between 50 and 100 microns along a 120-deg cone at about 315 deg before top-dead-center for an intake swirl angle of 30 deg. The spray penetration and vaporization were found to be insensitive to the turbulence levels within the cylinder. The results have also indicated that squish is necessary in order to increase the fuel vaporization rate and mixing.

  1. Lift vs. drag based mechanisms for vertical force production in the smallest flying insects.

    PubMed

    Jones, S K; Laurenza, R; Hedrick, T L; Griffith, B E; Miller, L A

    2015-11-07

    We used computational fluid dynamics to determine whether lift- or drag-based mechanisms generate the most vertical force in the flight of the smallest insects. These insects fly at Re on the order of 4-60 where viscous effects are significant. Detailed quantitative data on the wing kinematics of the smallest insects is not available, and as a result both drag- and lift-based strategies have been suggested as the mechanisms by which these insects stay aloft. We used the immersed boundary method to solve the fully-coupled fluid-structure interaction problem of a flexible wing immersed in a two-dimensional viscous fluid to compare three idealized hovering kinematics: a drag-based stroke in the vertical plane, a lift-based stroke in the horizontal plane, and a hybrid stroke on a tilted plane. Our results suggest that at higher Re, a lift-based strategy produces more vertical force than a drag-based strategy. At the Re pertinent to small insect hovering, however, there is little difference in performance between the two strategies. A drag-based mechanism of flight could produce more vertical force than a lift-based mechanism for insects at Re<5; however, we are unaware of active fliers at this scale. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Metronome Cueing of Walking Reduces Gait Variability after a Cerebellar Stroke.

    PubMed

    Wright, Rachel L; Bevins, Joseph W; Pratt, David; Sackley, Catherine M; Wing, Alan M

    2016-01-01

    Cerebellar stroke typically results in increased variability during walking. Previous research has suggested that auditory cueing reduces excessive variability in conditions such as Parkinson's disease and post-stroke hemiparesis. The aim of this case report was to investigate whether the use of a metronome cue during walking could reduce excessive variability in gait parameters after a cerebellar stroke. An elderly female with a history of cerebellar stroke and recurrent falling undertook three standard gait trials and three gait trials with an auditory metronome. A Vicon system was used to collect 3-D marker trajectory data. The coefficient of variation was calculated for temporal and spatial gait parameters. SDs of the joint angles were calculated and used to give a measure of joint kinematic variability. Step time, stance time, and double support time variability were reduced with metronome cueing. Variability in the sagittal hip, knee, and ankle angles were reduced to normal values when walking to the metronome. In summary, metronome cueing resulted in a decrease in variability for step, stance, and double support times and joint kinematics. Further research is needed to establish whether a metronome may be useful in gait rehabilitation after cerebellar stroke and whether this leads to a decreased risk of falling.

  3. Metronome Cueing of Walking Reduces Gait Variability after a Cerebellar Stroke

    PubMed Central

    Wright, Rachel L.; Bevins, Joseph W.; Pratt, David; Sackley, Catherine M.; Wing, Alan M.

    2016-01-01

    Cerebellar stroke typically results in increased variability during walking. Previous research has suggested that auditory cueing reduces excessive variability in conditions such as Parkinson’s disease and post-stroke hemiparesis. The aim of this case report was to investigate whether the use of a metronome cue during walking could reduce excessive variability in gait parameters after a cerebellar stroke. An elderly female with a history of cerebellar stroke and recurrent falling undertook three standard gait trials and three gait trials with an auditory metronome. A Vicon system was used to collect 3-D marker trajectory data. The coefficient of variation was calculated for temporal and spatial gait parameters. SDs of the joint angles were calculated and used to give a measure of joint kinematic variability. Step time, stance time, and double support time variability were reduced with metronome cueing. Variability in the sagittal hip, knee, and ankle angles were reduced to normal values when walking to the metronome. In summary, metronome cueing resulted in a decrease in variability for step, stance, and double support times and joint kinematics. Further research is needed to establish whether a metronome may be useful in gait rehabilitation after cerebellar stroke and whether this leads to a decreased risk of falling. PMID:27313563

  4. Comparison of neuromuscular abnormalities between upper and lower extremities in hemiparetic stroke.

    PubMed

    Mirbagheri, M M; AliBiglou, L; Thajchayapong, M; Lilaonitkul, T; Rymer, W Z

    2006-01-01

    We studied the neuromuscular mechanical properties of the elbow and ankle joints in chronic, hemiparetic stroke patients and healthy subjects. System identification techniques were used to characterize the mechanical abnormalities of these joints and to identify the contribution of intrinsic and reflex stiffness to these abnormalities. Modulation of intrinsic and reflex stiffness with the joint angle was studied by applying PRBS perturbations to the joint at different joint angles. The experiments were performed for both spastic (stroke) and contralateral (control) sides of stroke patients and one side of healthy (normal) subjects. We found reflex stiffness gain (GR) was significantly larger in the stroke than the control side for both elbow and ankle joints. GR was also strongly position dependent in both joints. However, the modulation of GR with position was slightly different in two joints. GR was also larger in the control than the normal joints but the differences were significant only for the ankle joint. Intrinsic stiffness gain (K) was also significantly larger in the stroke than the control joint at elbow extended positions and at ankle dorsiflexed positions. Modulation of K with the ankle angle was similar for stroke, control and normal groups. In contrast, the position dependency of the elbow was different. K was larger in the control than normal ankle whereas it was lower in the control than normal elbow. However, the differences were not significant for any joint. The findings demonstrate that both reflex and intrinsic stiffness gain increase abnormally in both upper and lower extremities. However, the major contribution of intrinsic and reflex stiffness to the abnormalities is at the end of ROM and at the middle ROM, respectively. The results also demonstrate that the neuromuscular properties of the contralateral limb are not normal suggesting that it may not be used as a suitable control at least for the ankle study.

  5. [Movement analysis of upper extremity hemiparesis in patients with cerebrovascular disease: a pilot study].

    PubMed

    Molina Rueda, F; Rivas Montero, F M; Pérez de Heredia Torres, M; Alguacil Diego, I M; Molero Sánchez, A; Miangolarra Page, J C

    2012-01-01

    As a result of neurophysiological injury, stroke patients have mobility limitations, mainly on the side of the body contralateral to the lesioned hemisphere. The purpose of this study is to quantify motor compensation strategies in stroke patients during the activity of drinking water from a glass. Four male patient with cerebrovascular disease and four right-handed, healthy male control subjects. The motion analysis was conducted using the Vicon Motion System(®) and surface electromyography equipment ZeroWire Aurion(®). We analysed elbow, shoulder and trunk joint movements and performed a qualitative analysis of the sequence of muscle activation. Trunk, shoulder and elbow movements measured in the stroke patient along the sagittal plane decreased during the drinking from a glass activity, while the movements in the shoulder in the coronal plane and trunk increased. As for the sequence of muscle activation, anterior, middle and posterior deltoid all contracted in the patient group during the task, while the upper trapezius activation remained throughout the activity. Quantitative analysis of movement provides quantitative information on compensation strategies used by stroke patients, and is therefore, clinically relevant. Copyright © 2011 Sociedad Española de Neurología. Published by Elsevier Espana. All rights reserved.

  6. On motions of a carrier with a mobile load along a rough inclined plane

    NASA Astrophysics Data System (ADS)

    Bilchenko, Grigory; Bilchenko, Grigory; Bilchenko, Nataly

    2018-05-01

    A mechanical system consisting of a carrier and a load is considered. The load can move respectively to the carrier according to a predetermined motion law. The carrier can move translationally along a rectilinear trajectory on a rough inclined plane. The trajectory is the line of the greatest descent. The axis of the rectilinear channel, along which the load moves, is located in a vertical plane passing through the trajectory of the carrier. The Coulomb dry friction model is applied for simulation the forces of resistance to the motion of the carrier from the side of the underlying inclined plane. The extreme value of plane inclination angle at which the carrier is at rest, when the load is stationary, is obtained by taking into account the frictional forces of sliding at rest. Differential equations of motion of a carrier with a load moving with respect to the carrier are obtained taking into account the requirement of motion of the carrier along an inclined plane without detachment. The determining relationships are given which made it possible to classify the types of carrier motion when the channel setting angle and the plane inclination angle are related by a certain inequality. The results of computational experiments are presented.

  7. Vertical facial height and its correlation with facial width and depth: Three dimensional cone beam computed tomography evaluation based on dry skulls.

    PubMed

    Wang, Ming Feng; Otsuka, Takero; Akimoto, Susumu; Sato, Sadao

    2013-01-01

    The aim of the present study was to evaluate how vertical facial height correlates with mandibular plane angle, facial width and depth from a three dimensional (3D) viewing angle. In this study 3D cephalometric landmarks were identified and measurements from 43 randomly selected cone beam computed tomography (CBCT) images of dry skulls from the Weisbach collection of Vienna Natural History Museum were analyzed. Pearson correlation coefficients of facial height measurements and mandibular plane angle and the correlation coefficients of height-width and height-depth were calculated, respectively. The mandibular plane angle (MP-SN) significantly correlated with ramus height (Co-Go) and posterior facial height (PFH) but not with anterior lower face height (ALFH) or anterior total face height (ATFH). The ALFH and ATFH showed significant correlation with anterior cranial base length (S-N), whereas PFH showed significant correlation with the mandible (S-B) and maxilla (S-A) anteroposterior position. High or low mandibular plane angle might not necessarily be accompanied by long or short anterior face height, respectively. The PFH rather than AFH is assumed to play a key role in the vertical facial type whereas AFH seems to undergo relatively intrinsic growth.

  8. The relation between knee flexion angle and anterior cruciate ligament femoral tunnel characteristics: a cadaveric study comparing a standard and a far anteromedial portal.

    PubMed

    Alavekios, Damon; Peterson, Alexander; Patton, John; McGarry, Michelle H; Lee, Thay Q

    2014-11-01

    The purpose of this study was to compare the anterior cruciate ligament (ACL) femoral tunnel characteristics between 2 common arthroscopic portals used for ACL reconstruction, a standard anteromedial portal and a far anteromedial portal. Seven cadaveric knees were used. A 1.25-mm Kirschner wire was drilled through the center of the ACL femoral footprint and through the distal femur from the standard anteromedial and far anteromedial portals at knee flexion angles of 100°, 120°, and 140°. No formal tunnels were drilled. Each tunnel exit point was marked with a colored pin. After all tunnels were created, the specimens were digitized with a MicroScribe device (Revware, Raleigh, NC) to measure the tunnel length; distance to the posterior femoral cortical wall (posterior cortical margin); and tunnel orientation in the sagittal, coronal, and axial planes. The standard anteromedial portal resulted in a longer tunnel length, a less horizontal tunnel in the coronal plane, and a greater posterior cortical margin compared with the far anteromedial portal at all knee flexion angles. For both portal locations, the tunnel length and posterior cortical margin increased, and the tunnel position became more horizontal in the coronal plane, more anterior in the sagittal plane, and less horizontal in the transverse plane as knee flexion increased. Portal position affects femoral tunnel characteristics, with results favoring the more laterally positioned standard anteromedial portal at all flexion angles. Increasing the knee flexion angle leads to a longer femoral tunnel length and posterior femoral cortical margin with either portal position. Understanding how portal positioning and knee flexion angle affect femoral tunnel orientation and characteristics may lead to improved surgical outcomes after ACL reconstruction. Published by Elsevier Inc.

  9. Permanent magnets as biasing mechanism for improving the performance of circular dielectric elastomer out-of-plane actuators

    NASA Astrophysics Data System (ADS)

    Loew, P.; Rizzello, G.; Seelecke, S.

    2017-04-01

    Dielectric Elastomers (DE) represent an attractive technology for the realization of mechatronic actuators, due to their lightweight, high energy density, high energy efficiency, scalability, and low noise features. In order to produce a stroke, a DE membrane needs to be pre-loaded with a mechanical biasing mechanism. In our previous works, we compared the stroke achieved with different biasing mechanisms for a circular out-of-plane DE Actuator (DEA), i.e., hanging masses, linear and bi-stable springs. The novel contribution of this paper is the investigation of a biasing design approach based on permanent magnets. The resulting magnet-based actuators are usually more compact than the spring-based ones, allowing to obtain more compact systems. Two design solutions are proposed and compared, namely a first one characterized by a stable actuation, and a second one which permits to achieve a higher stroke, but it is intrinsically unstable. The effectiveness of the novel design solution is assessed by means of several experiments.

  10. Influence of Handrim Wheelchair Propulsion Training in Adolescent Wheelchair Users, A Pilot Study

    PubMed Central

    Dysterheft, Jennifer L.; Rice, Ian M.; Rice, Laura A.

    2015-01-01

    Ten full-time adolescent wheelchair users (ages 13–18) completed a total of three propulsion trials on carpet and tile surfaces, at a self-selected velocity, and on a concrete surface, at a controlled velocity. All trials were performed in their personal wheelchair with force and moment sensing wheels attached bilaterally. The first two trials on each surface were used as pre-intervention control trials. The third trial was performed after receiving training on proper propulsion technique. Peak resultant force, contact angle, stroke frequency, and velocity were recorded during all trials for primary analysis. Carpet and tile trials resulted in significant increases in contact angle and peak total force with decreased stroke frequency after training. During the velocity controlled trials on concrete, significant increases in contact angle occurred, as well as decreases in stroke frequency after training. Overall, the use of a training video and verbal feedback may help to improve short-term propulsion technique in adolescent wheelchair users and decrease the risk of developing upper limb pain and injury. PMID:26042217

  11. Horizontal fields generated by return strokes

    NASA Technical Reports Server (NTRS)

    Cooray, Vernon

    1991-01-01

    Horizontal fields generated by return strokes play an important role in the interaction of lightning generated electric fields with power lines. In many of the recent investigations on the interaction of lightning electromagnetic fields with power lines, the horizontal field was calculated by employing the expression for the tilt of the electric field of a plane wave propagating over finitely conducting earth. The method is suitable for calculating horizontal fields generated by return strokes at distances as close as 200m. At these close ranges, the use of the wavetilt expression can cause large errors.

  12. Low-Angle-Incidence Microchannel Epitaxy of a-Plane GaN Grown by Ammonia-Based Metal-Organic Molecular Beam Epitaxy

    NASA Astrophysics Data System (ADS)

    Lin, Chia-Hung; Uchiyama, Shota; Maruyama, Takahiro; Naritsuka, Shigeya

    2012-04-01

    Low-angle-incidence microchannel epitaxy (LAIMCE) of a-plane GaN was performed using ammonia-based metal-organic molecular beam epitaxy to obtain wide and thin lateral overgrowth over a SiO2 mask. Trimethylgallium (TMG) was supplied perpendicular to the openings cut in the mask with a low incident angle of 5° relative to the substrate plane. The [NH3]/[TMG] ratio (R) dependence of GaN LAIMCE was optimized by varying R from 5 to 30. A wide lateral overgrowth of 3.7 µm with a dislocation density below the transmission electron microscope detection limit was obtained at R=15 for a thickness of 520 nm.

  13. AE Source Orientation by Plate Wave Analysis

    NASA Technical Reports Server (NTRS)

    Gorman, Michael R.; Prosser, William H.

    1991-01-01

    Lead breaks (Hsu-Neilsen source) were used to generate simulated acoustic emission signals in an aluminum plate at angles of 0, 30, 60, and 90 degrees with respect to the plane of the plate. This was accomplished by breaking the lead on slots cut into the plate at the respective angles. The out-of-plane and in-plane displacement components of the resulting signals were detected by broad band transducers and digitized. Analysis of the waveforms showed them to consist of the extensional and flexural plate modes. The amplitude of both components of the two modes was dependent on the source orientation angle. This suggests that plate wave analysis may be used to determine the source orientation of acoustic emission sources.

  14. Direct observation of the myosin Va recovery stroke that contributes to unidirectional stepping along actin.

    PubMed

    Shiroguchi, Katsuyuki; Chin, Harvey F; Hannemann, Diane E; Muneyuki, Eiro; De La Cruz, Enrique M; Kinosita, Kazuhiko

    2011-04-01

    Myosins are ATP-driven linear molecular motors that work as cellular force generators, transporters, and force sensors. These functions are driven by large-scale nucleotide-dependent conformational changes, termed "strokes"; the "power stroke" is the force-generating swinging of the myosin light chain-binding "neck" domain relative to the motor domain "head" while bound to actin; the "recovery stroke" is the necessary initial motion that primes, or "cocks," myosin while detached from actin. Myosin Va is a processive dimer that steps unidirectionally along actin following a "hand over hand" mechanism in which the trailing head detaches and steps forward ∼72 nm. Despite large rotational Brownian motion of the detached head about a free joint adjoining the two necks, unidirectional stepping is achieved, in part by the power stroke of the attached head that moves the joint forward. However, the power stroke alone cannot fully account for preferential forward site binding since the orientation and angle stability of the detached head, which is determined by the properties of the recovery stroke, dictate actin binding site accessibility. Here, we directly observe the recovery stroke dynamics and fluctuations of myosin Va using a novel, transient caged ATP-controlling system that maintains constant ATP levels through stepwise UV-pulse sequences of varying intensity. We immobilized the neck of monomeric myosin Va on a surface and observed real time motions of bead(s) attached site-specifically to the head. ATP induces a transient swing of the neck to the post-recovery stroke conformation, where it remains for ∼40 s, until ATP hydrolysis products are released. Angle distributions indicate that the post-recovery stroke conformation is stabilized by ≥ 5 k(B)T of energy. The high kinetic and energetic stability of the post-recovery stroke conformation favors preferential binding of the detached head to a forward site 72 nm away. Thus, the recovery stroke contributes to unidirectional stepping of myosin Va.

  15. Limited-angle tomography for analyzer-based phase-contrast X-ray imaging

    PubMed Central

    Majidi, Keivan; Wernick, Miles N; Li, Jun; Muehleman, Carol; Brankov, Jovan G

    2014-01-01

    Multiple-Image Radiography (MIR) is an analyzer-based phase-contrast X-ray imaging method (ABI), which is emerging as a potential alternative to conventional radiography. MIR simultaneously generates three planar parametric images containing information about scattering, refraction and attenuation properties of the object. The MIR planar images are linear tomographic projections of the corresponding object properties, which allows reconstruction of volumetric images using computed tomography (CT) methods. However, when acquiring a full range of linear projections around the tissue of interest is not feasible or the scanning time is limited, limited-angle tomography techniques can be used to reconstruct these volumetric images near the central plane, which is the plane that contains the pivot point of the tomographic movement. In this work, we use computer simulations to explore the applicability of limited-angle tomography to MIR. We also investigate the accuracy of reconstructions as a function of number of tomographic angles for a fixed total radiation exposure. We use this function to find an optimal range of angles over which data should be acquired for limited-angle tomography MIR (LAT-MIR). Next, we apply the LAT-MIR technique to experimentally acquired MIR projections obtained in a cadaveric human thumb study. We compare the reconstructed slices near the central plane to the same slices reconstructed by CT-MIR using the full angular view around the object. Finally, we perform a task-based evaluation of LAT-MIR performance for different numbers of angular views, and use template matching to detect cartilage in the refraction image near the central plane. We use the signal-to-noise ratio of this test as the detectability metric to investigate an optimum range of tomographic angles for detecting soft tissues in LAT-MIR. Both results show that there is an optimum range of angular view for data acquisition where LAT-MIR yields the best performance, comparable to CT-MIR only if one considers volumetric images near the central plane and not the whole volume. PMID:24898008

  16. Limited-angle tomography for analyzer-based phase-contrast x-ray imaging

    NASA Astrophysics Data System (ADS)

    Majidi, Keivan; Wernick, Miles N.; Li, Jun; Muehleman, Carol; Brankov, Jovan G.

    2014-07-01

    Multiple-image radiography (MIR) is an analyzer-based phase-contrast x-ray imaging method, which is emerging as a potential alternative to conventional radiography. MIR simultaneously generates three planar parametric images containing information about scattering, refraction and attenuation properties of the object. The MIR planar images are linear tomographic projections of the corresponding object properties, which allows reconstruction of volumetric images using computed tomography (CT) methods. However, when acquiring a full range of linear projections around the tissue of interest is not feasible or the scanning time is limited, limited-angle tomography techniques can be used to reconstruct these volumetric images near the central plane, which is the plane that contains the pivot point of the tomographic movement. In this work, we use computer simulations to explore the applicability of limited-angle tomography to MIR. We also investigate the accuracy of reconstructions as a function of number of tomographic angles for a fixed total radiation exposure. We use this function to find an optimal range of angles over which data should be acquired for limited-angle tomography MIR (LAT-MIR). Next, we apply the LAT-MIR technique to experimentally acquired MIR projections obtained in a cadaveric human thumb study. We compare the reconstructed slices near the central plane to the same slices reconstructed by CT-MIR using the full angular view around the object. Finally, we perform a task-based evaluation of LAT-MIR performance for different numbers of angular views, and use template matching to detect cartilage in the refraction image near the central plane. We use the signal-to-noise ratio of this test as the detectability metric to investigate an optimum range of tomographic angles for detecting soft tissues in LAT-MIR. Both results show that there is an optimum range of angular view for data acquisition where LAT-MIR yields the best performance, comparable to CT-MIR only if one considers volumetric images near the central plane and not the whole volume.

  17. A Highly Backdrivable, Lightweight Knee Actuator for Investigating Gait in Stroke

    PubMed Central

    Sulzer, James S.; Roiz, Ronald A.; Peshkin, Michael A.; Patton, James L.

    2012-01-01

    Many of those who survive a stroke develop a gait disability known as stiff-knee gait (SKG). Characterized by reduced knee flexion angle during swing, people with SKG walk with poor energy efficiency and asymmetry due to the compensatory mechanisms required to clear the foot. Previous modeling studies have shown that knee flexion activity directly before the foot leaves the ground, and this should result in improved knee flexion angle during swing. The goal of this research is to physically test this hypothesis using robotic intervention. We developed a device that is capable of assisting knee flexion torque before swing but feels imperceptible (transparent) for the rest of the gait cycle. This device uses sheathed Bowden cable to control the deflection of a compliant torsional spring in a configuration known as a Series Elastic Remote Knee Actuator (SERKA). In this investigation, we describe the design and evaluation of SERKA, which includes a pilot experiment on stroke subjects. SERKA could supply a substantial torque (12 N· m) in less than 20 ms, with a maximum torque of 41 N·m. The device resisted knee flexion imperceptibly when desired, at less than 1 N·m rms torque during normal gait. With the remote location of the actuator, the user experiences a mass of only 1.2 kg on the knee. We found that the device was capable of increasing both peak knee flexion angle and velocity during gait in stroke subjects. Thus, the SERKA is a valid experimental device that selectively alters knee kinetics and kinematics in gait after stroke. PMID:22563305

  18. Gait training with partial body weight support during overground walking for individuals with chronic stroke: a pilot study

    PubMed Central

    2011-01-01

    Background It is not yet established if the use of body weight support (BWS) systems for gait training is effective per se or if it is the combination of BWS and treadmill that improves the locomotion of individuals with gait impairment. This study investigated the effects of gait training on ground level with partial BWS in individuals with stroke during overground walking with no BWS. Methods Twelve individuals with chronic stroke (53.17 ± 7.52 years old) participated of a gait training program with BWS during overground walking, and were evaluated before and after the gait training period. In both evaluations, individuals were videotaped walking at a self-selected comfortable speed with no BWS. Measurements were obtained for mean walking speed, step length, stride length and speed, toe-clearance, durations of total double stance and single-limb support, and minimum and maximum foot, shank, thigh, and trunk segmental angles. Results After gait training, individuals walked faster, with symmetrical steps, longer and faster strides, and increased toe-clearance. Also, they displayed increased rotation of foot, shank, thigh, and trunk segmental angles on both sides of the body. However, the duration of single-limb support remained asymmetrical between each side of the body after gait training. Conclusions Gait training individuals with chronic stroke with BWS during overground walking improved walking in terms of temporal-spatial parameters and segmental angles. This training strategy might be adopted as a safe, specific and promising strategy for gait rehabilitation after stroke. PMID:21864373

  19. Crank angle detecting system for engines

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

    Yuzawa, H.; Nishiyama, M.; Nakamura, K.

    1988-05-31

    An ignition system for a multi-cylinder internal combustion engine is described comprising: (a) engine cylinders in which spark plugs are installed respectively, (b) indicating means disposed so as to synchronize with an engine crankshaft and formed with a large number of slits and a small number of slits, the large number of slits being provided for indicating crankshaft angular positions and the small number of slits being provided for indicating predetermined piston strokes and wherein the small number of slits have mutually different widths from each other to distinguish between piston strokes of at least the groups of cylinders; (c)more » sensing means for sensing crankshaft angular positions in cooperation with the large number of slits of the indicating means and outputting a crank angle signal representing the crankshaft angular position and for sensing the predetermined piston strokes in cooperation with the small number of slits and outputting different width piston stroke signals corresponding to the different width slits; (d) discriminating means for identifying each cylinder group and outputting cylinder group identification signals on the basis of the different width stroke signals derived from the sensing means; (e) ignition timing determining means for generating an ignition timing signal on the basis of the crank angle signal; (f) ignition coil controlling means for generating ignition coil current signals corresponding to the cylinder group identification signals; and (g) ignition timing controlling means for generating cylinder group ignition signals in response to the ignition coil current signals and ignition timing signal so that the spark plugs of each cylinder group are ignited at a proper time.« less

  20. Predictors of favorable soft tissue profile outcomes following Class II Twin-block treatment

    PubMed Central

    Kim, Ji-Eun; Mah, Su-Jung; Kim, Tae-Woo; Kim, Su-Jung; Park, Ki-Ho

    2018-01-01

    Objective The aim of this study was to determine cephalometric factors that help predict favorable soft-tissue profile outcomes following treatment with the Class II Twin-block appliance. Methods Pre- and post-treatment lateral cephalograms of 45 patients treated with the Class II Twin-block appliance were retrospectively analyzed. Profile silhouettes were drawn from the cephalograms and evaluated by three orthodontists in order to determine the extent of improvement. Samples were divided into a favorable group (upper 30% of visual analogue scale [VAS] scores, n = 14) and an unfavorable group (lower 30% of VAS scores, n = 14). Skeletal and soft-tissue measurements were performed on the cephalograms and an intergroup comparison was conducted. Results An independent t-test revealed that the following pre-treatment values were lower in the favorable group compared to the unfavorable group: lower incisor to mandibular plane angle, lower incisor to pogonion distance, point A-nasion-point B angle, sella-nasion line (SN) to maxillary plane angle, SN to mandibular plane angle, gonial angle, and symphysis inclination. The favorable group had a larger incisor inclination to occlusal plane. Moreover, the favorable group showed larger post-treatment changes in gonial angle, B point projection, and pogonion projection than did the unfavorable group. Conclusions Class II malocclusion patients with a low divergent skeletal pattern and reduced lower incisor protrusions are likely to show more improvement in soft-tissue profile outcomes following Class II Twin-block treatment. PMID:29291184

  1. Usefulness of the "grand-piano sign" for determining femoral rotational alignment in total knee arthroplasty.

    PubMed

    Ohmori, Takaaki; Kabata, Tamon; Kajino, Yoshitomo; Taga, Tadashi; Inoue, Daisuke; Yamamoto, Takashi; Takagi, Tomoharu; Yoshitani, Junya; Ueno, Takuro; Tsuchiya, Hiroyuki

    2018-01-01

    The "grand-piano sign" is a well-known indicator of proper rotational femoral alignment. We investigated changes in the shape of the femoral anterior cutting plane by changing the rotational alignment, anterior portion depth, and cutting plane flexion angle. We simulated various cutting planes after cutting the anterior portion of the femur next to the distal femoral osteotomy in 50 patients with varus knee and also a femoral anterior osteotomy with four degree (S group) and seven degree (T group) flexion angles regarding the mechanical axis. We defined the final cutting plane as the farthest position that we could reach without making a notch and the precutting plane as two millimeters anterior from the final cutting plane. The simulated resection plane was rotated to produce external and internal rotation angles of 0°, three degrees, and five degrees relative to the surgical transepicondylar axis (SEA). We investigated medial and lateral portions of the femoral anterior cutting plane length ratio (M/L). When we cut parallel to SEA, M/L was 0.67±0.09 and 0.62±0.12 in the T and S groups, respectively. M/L was approximately 0.8 and 0.5 with five degree internal and external rotations, respectively (P<0.01). On comparing final cutting and precutting planes, there were no significant differences in M/L without five degree external rotation in the T group and no significant difference in any case in the S group (P>0.01). The ideal M/L of the femoral anterior cutting plane was 0.62-0.67. M/L did not change with a precutting plane in almost all rotational patterns. Copyright © 2017. Published by Elsevier B.V.

  2. Kinematics of Visually-Guided Eye Movements

    PubMed Central

    Hess, Bernhard J. M.; Thomassen, Jakob S.

    2014-01-01

    One of the hallmarks of an eye movement that follows Listing’s law is the half-angle rule that says that the angular velocity of the eye tilts by half the angle of eccentricity of the line of sight relative to primary eye position. Since all visually-guided eye movements in the regime of far viewing follow Listing’s law (with the head still and upright), the question about its origin is of considerable importance. Here, we provide theoretical and experimental evidence that Listing’s law results from a unique motor strategy that allows minimizing ocular torsion while smoothly tracking objects of interest along any path in visual space. The strategy consists in compounding conventional ocular rotations in meridian planes, that is in horizontal, vertical and oblique directions (which are all torsion-free) with small linear displacements of the eye in the frontal plane. Such compound rotation-displacements of the eye can explain the kinematic paradox that the fixation point may rotate in one plane while the eye rotates in other planes. Its unique signature is the half-angle law in the position domain, which means that the rotation plane of the eye tilts by half-the angle of gaze eccentricity. We show that this law does not readily generalize to the velocity domain of visually-guided eye movements because the angular eye velocity is the sum of two terms, one associated with rotations in meridian planes and one associated with displacements of the eye in the frontal plane. While the first term does not depend on eye position the second term does depend on eye position. We show that compounded rotation - displacements perfectly predict the average smooth kinematics of the eye during steady- state pursuit in both the position and velocity domain. PMID:24751602

  3. Characteristics of a Single Float Seaplane During Take-off

    NASA Technical Reports Server (NTRS)

    Crowley, J W , Jr; Ronan, K M

    1925-01-01

    At the request of the Bureau of Aeronautics, Navy Department, the National Advisory Committee for Aeronautics at Langley Field is investigating the get-away characteristics of an N-9H, a DT-2, and an F-5l, as representing, respectively, a single float, a double float, and a boat type of seaplane. This report covers the investigation conducted on the N-9H. The results show that a single float seaplane trims aft in taking off. Until a planing condition is reached the angle of attack is about 15 degrees and is only slightly affected by controls. When planing it seeks a lower angle, but is controllable through a widening range, until at the take-off it is possible to obtain angles of 8 degrees to 15 degrees with corresponding speeds of 53 to 41 M. P. H. or about 40 per cent of the speed range. The point of greatest resistance occurs at about the highest angle of a pontoon planing angle of 9 1/2 degrees and at a water speed of 24 M. P. H.

  4. A Different Angle on Perspective

    ERIC Educational Resources Information Center

    Frantz, Marc

    2012-01-01

    When a plane figure is photographed from different viewpoints, lengths and angles appear distorted. Hence it is often assumed that lengths, angles, protractors, and compasses have no place in projective geometry. Here we describe a sense in which certain angles are preserved by projective transformations. These angles can be constructed with…

  5. Experimental demonstration of in-plane negative-angle refraction with an array of silicon nanoposts.

    PubMed

    Wu, Aimin; Li, Hao; Du, Junjie; Ni, Xingjie; Ye, Ziliang; Wang, Yuan; Sheng, Zhen; Zou, Shichang; Gan, Fuwan; Zhang, Xiang; Wang, Xi

    2015-03-11

    Controlling an optical beam is fundamental in optics. Recently, unique manipulation of optical wavefronts has been successfully demonstrated by metasurfaces. However, these artificially engineered nanostructures have thus far been limited to operate on light beams propagating out-of-plane. The in-plane operation is critical for on-chip photonic applications. Here, we demonstrate an anomalous negative-angle refraction of a light beam propagating along the plane, by designing a thin dielectric array of silicon nanoposts. The circularly polarized dipoles induced by the high-permittivity nanoposts at the scattering resonance significantly shape the wavefront of the light beam and bend it anomalously. The unique capability of a thin line of the nanoposts for manipulating in-plane wavefronts makes the device extremely compact. The low loss all-dielectric structure is compatible with complementary metal-oxide semiconductor technologies, offering an effective solution for in-plane beam steering and routing for on-chip photonics.

  6. Universal Documentation System Handbook. Volume 2. Requirement Formats and Instructions, Program Introduction, Program Requirements Document/Operations Requirements.

    DTIC Science & Technology

    1989-08-01

    horizontal plane is defined as a plane normal to the geocentric position vector. Inertial Azimuth Heading Angle entries are the angles measured east of north...0CATICN: Enter the areas or locations that are to be staffed with redical perscnel, i.e., Vandenberg AFB Hospital, PMIC; or offshore boats, etc. NUMB

  7. In plane oscillation of a bifilar pendulum

    NASA Astrophysics Data System (ADS)

    Hinrichsen, Peter F.

    2016-11-01

    The line tensions, the horizontal and vertical accelerations as well as the period of large angle oscillations parallel to the plane of a bifilar suspension are presented and have been experimentally investigated using strain gauges and a smart phone. This system has a number of advantages over the simple pendulum for studying large angle oscillations, and for measuring the acceleration due to gravity.

  8. Optimal approach for complete liver tumor ablation using radiofrequency ablation: a simulation study.

    PubMed

    Givehchi, Sogol; Wong, Yin How; Yeong, Chai Hong; Abdullah, Basri Johan Jeet

    2018-04-01

    To investigate the effect of radiofrequency ablation (RFA) electrode trajectory on complete tumor ablation using computational simulation. The RFA of a spherical tumor of 2.0 cm diameter along with 0.5 cm clinical safety margin was simulated using Finite Element Analysis software. A total of 86 points inside one-eighth of the tumor volume along the axial, sagittal and coronal planes were selected as the target sites for electrode-tip placement. The angle of the electrode insertion in both craniocaudal and orbital planes ranged from -90° to +90° with 30° increment. The RFA electrode was simulated to pass through the target site at different angles in combination of both craniocaudal and orbital planes before being advanced to the edge of the tumor. Complete tumor ablation was observed whenever the electrode-tip penetrated through the epicenter of the tumor regardless of the angles of electrode insertion in both craniocaudal and orbital planes. Complete tumor ablation can also be achieved by placing the electrode-tip at several optimal sites and angles. Identification of the tumor epicenter on the central slice of the axial images is essential to enhance the success rate of complete tumor ablation during RFA procedures.

  9. Tunable hard X-ray spectrometer utilizing asymmetric planes of a quartz transmission crystal

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

    Seely, John F., E-mail: seelyjf@gmail.com; Feldman, Uri; Henins, Albert

    2016-05-15

    A Cauchois type hard x-ray spectrometer was developed that utilizes the (301) diffraction planes at an asymmetric angle of 23.51° to the normal to the surface of a cylindrically curved quartz transmission crystal. The energy coverage is tunable by rotating the crystal and the detector arm, and spectra were recorded in the 8 keV to 20 keV range with greater than 2000 resolving power. The high resolution results from low aberrations enabled by the nearly perpendicular angle of the diffracted rays with the back surface of the crystal. By using other asymmetric planes of the same crystal and rotating tomore » selected angles, the spectrometer can operate with high resolution up to 50 keV.« less

  10. Effect of air-entry angle on performance of a 2-stroke-cycle compression-ignition engine

    NASA Technical Reports Server (NTRS)

    Earle, Sherod L; Dutee, Francis J

    1937-01-01

    An investigation was made to determine the effect of variations in the horizontal and vertical air-entry angles on the performance characteristics of a single-cylinder 2-stroke-cycle compression-ignition test engine. Performance data were obtained over a wide range of engine speed, scavenging pressure, fuel quantity, and injection advance angle with the optimum guide vanes. Friction and blower-power curves are included for calculating the indicated and net performances. The optimum horizontal air-entry angle was found to be 60 degrees from the radial and the optimum vertical angle to be zero, under which conditions a maximum power output of 77 gross brake horsepower for a specific fuel consumption of 0.52 pound per brake horsepower-hour was obtained at 1,800 r.p.m. and 16-1/2 inches of Hg scavenging pressure. The corresponding specific output was 0.65 gross brake horsepower per cubic inch of piston displacement. Tests revealed that the optimum scavenging pressure increased linearly with engine speed. The brake mean effective pressure increased uniformly with air quantity per cycle for any given vane angle and was independent of engine speed and scavenging pressure.

  11. Negative ion formation and evolution in atmospheric pressure corona discharges between point-to-plane electrodes with arbitrary needle angle

    NASA Astrophysics Data System (ADS)

    Sekimoto, K.; Takayama, M.

    2010-12-01

    The change in the distribution pattern of negative ions HO-, NOx- and COx- observed on arbitrary point-to-plane electrode configuration has been investigated by varying the angle of needle to the plane electrode, under atmospheric pressure corona discharge conditions. The stationary inhomogeneous electric field distributions between the point-to-plane electrodes with arbitrary needle angle were calculated. The experimental and theoretical results obtained suggested that the negative ion evolutions progress along field lines established between the electrodes with arbitrary configurations and the resulting terminal ion formation on a given field line is attributable to the electric field strength on the needle tip surface where the field line arose. The NOx- and COx- ions were dominantly produced on the field lines arising from the needle tip apex region with the highest electric field strength, while the field lines emanating from the tip peripheral regions with lower field strength resulted in the formation of the HO- ion.

  12. Initial testing of a variable-stroke Stirling engine

    NASA Technical Reports Server (NTRS)

    Thieme, L. G.

    1985-01-01

    In support of the U.S. Department of Energy's Stirling Engine Highway Vehicle Systems Program, NASA Lewis Research Center is evaluating variable-stroke control for Stirling engines. The engine being tested is the Advenco Stirling engine; this engine was manufactured by Philips Research Laboratories of the Netherlands and uses a variable-angle swash-plate drive to achieve variable stroke operation. The engine is described, initial steady-state test data taken at Lewis are presented, a major drive system failure and subsequent modifications are described. Computer simulation results are presented to show potential part-load efficiency gains with variable-stroke control.

  13. The Age-Related Orientational Changes of Human Semicircular Canals.

    PubMed

    Lyu, Hui-Ying; Chen, Ke-Guang; Yin, Dong-Ming; Hong, Juan; Yang, Lin; Zhang, Tian-Yu; Dai, Pei-Dong

    2016-06-01

    Some changes are found in the labyrinth anatomy during postnatal development. Although the spatial orientation of semicircular canals was thought to be stable after birth, we investigated the age-related orientational changes of human semicircular canals during development. We retrospectively studied the computed tomography (CT) images of both ears of 76 subjects ranged from 1 to 70 years old. They were divided into 4 groups: group A (1-6 years), group B (7-12 years), group C (13-18 years), and group D (>18 years). The anatomical landmarks of the inner ear structures were determined from CT images. Their coordinates were imported into MATLAB software for calculating the semicircular canals orientation, angles between semicircular canal planes and the jugular bulb (JB) position. Differences between age groups were analyzed using multivariate statistics. Relationships between variables were analyzed using Pearson analysis. The angle between the anterior semicircular canal plane and the coronal plane, and the angle between the horizontal semicircular canal plane and the coronal plane were smaller in group D than those in group A (P<0.05). The JB position, especially the anteroposterior position of right JB, correlated to the semicircular canals orientation (P<0.05). However, no statistically significant differences in the angles between ipsilateral canal planes among different age groups were found. The semicircular canals had tendencies to tilt anteriorly simultaneously as a whole with age. The JB position correlated to the spatial arrangement of semicircular canals, especially the right JB. Our calculation method helps detect developmental and pathological changes in vestibular anatomy.

  14. The Origin of High-angle Dip-slip Earthquakes at Geothermal Fields in California

    NASA Astrophysics Data System (ADS)

    Barbour, A. J.; Schoenball, M.; Martínez-Garzón, P.; Kwiatek, G.

    2016-12-01

    We examine the source mechanisms of earthquakes occurring in three California geothermal fields: The Geysers, Salton Sea, and Coso. We find source mechanisms ranging from strike slip faulting, consistent with the tectonic settings, to dip slip with unusually steep dip angles which are inconsistent with local structures. For example, we identify a fault zone in the Salton Sea Geothermal Field imaged using precisely-relocated hypocenters with a dip angle of 60° yet double-couple focal mechanisms indicate higher-angle dip-slip on ≥75° dipping planes. We observe considerable temporal variability in the distribution of source mechanisms. For example, at the Salton Sea we find that the number of high angle dip-slip events increased after 1989, when net-extraction rates were highest. There is a concurrent decline in strike-slip and strike-slip-normal faulting, the mechanisms expected from regional tectonics. These unusual focal mechanisms and their spatio-temporal patterns are enigmatic in terms of our understanding of faulting in geothermal regions. While near-vertical fault planes are expected to slip in a strike-slip sense, and dip slip is expected to occur on moderately dipping faults, we observe dip slip on near-vertical fault planes. However, for plausible stress states and accounting for geothermal production, the resolved fault planes should be stable. We systematically analyze the source mechanisms of these earthquakes using full moment tensor inversion to understand the constraints imposed by assuming a double-couple source. Applied to The Geysers field, we find a significant reduction in the number of high-angle dip-slip mechanisms using the full moment tensor. The remaining mechanisms displaying high-angle dip-slip could be consistent with faults accommodating subsidence and compaction associated with volumetric strain changes in the geothermal reservoir.

  15. A cephalometric study to establish the relationship of the occlusal plane to the three different ala-tragal lines and the Frankfort horizontal plane in different head forms.

    PubMed

    Subhas, S; Rupesh, P L; Devanna, R; Kumar, D R V; Paliwal, A; Solanki, P

    2017-04-01

    The aim of the study is to compare the relationship of the occlusal plane to 3 different ala-tragal lines, namely the superior, middle and inferior lines, in individuals having different head forms and its relation to the Frankfort horizontal plane. A total of 75 lateral cephalometric radiographs of subjects with natural dentition, having full complement of teeth, between the age group of 18-25 were screened and selected. Lateral cephalogram were made for each subjects in an open mouth position. Prior to making the lateral cephalogram, radiopaque markers were placed on the superior, middle and inferior tragus points and on the inferior border of the ala of the nose. Cephalometric tracing was done over each cephalogram. In mesiocephalic head form the middle ala-tragal line was most parallel to the occlusal plane having a mean angle of (1.96°). In dolichocephalic headform, the superior ala-tragal line was most parallel to the occlusal plane having a mean angle of (0.48°). In brachycephalic head form, the middle ala-tragal line was most parallel to the occlusal plane having a mean angle of (2.08°). The mean angulations of occlusal plane to FH plane is 11.04°, 10.16° and 10.60° in mesiocephalic, dolichocephalic and brachycephalic head forms, respectively. The study concludes that the middle ala-tragal line can be used as a reference for the mesiocephalic head form and the superior ala-tragal line for the dolichocephalic and brachycephalic head form as a reference to establish the occlusal plane. Copyright © 2016. Published by Elsevier Masson SAS.

  16. Lower incisor inclination regarding different reference planes.

    PubMed

    Zataráin, Brenda; Avila, Josué; Moyaho, Angeles; Carrasco, Rosendo; Velasco, Carmen

    2016-09-01

    The purpose of this study was to assess the degree of lower incisor inclination with respect to different reference planes. It was an observational, analytical, longitudinal, prospective study conducted on 100 lateral cephalograms which were corrected according to the photograph in natural head position in order to draw the true vertical plane (TVP). The incisor mandibular plane angle (IMPA) was compensated to eliminate the variation of the mandibular plane growth type with the formula "FMApx.- 25 (FMA) + IMPApx. = compensated IMPA (IMPACOM)". As the data followed normal distribution determined by the KolmogorovSmirnov test, parametric tests were used for the statistical analysis, Ttest, ANOVA and Pearson coefficient correlation test. Statistical analysis was performed using a statistical significance of p <0.05. There is correlation between TVP and NB line (NB) (0.8614), Frankfort mandibular incisor angle (FMIA) (0.8894), IMPA (0.6351), Apo line (Apo) (0.609), IMPACOM (0.8895) and McHorris angle (MH) (0.7769). ANOVA showed statistically significant differences between the means for the 7 variables with 95% confidence level, P=0.0001. The multiple range test showed no significant difference among means: APoNB (0.88), IMPAMH (0.36), IMPANB (0.65), FMIAIMPACOM (0.01), FMIATVP (0.18), TVPIMPACOM (0.17). There was correlation among all reference planes. There were statistically significant differences among the means of the planes measured, except for IMPACOM, FMIA and TVP. The IMPA differed significantly from the IMPACOM. The compensated IMPA and the FMIA did not differ significantly from the TVP. The true horizontal plane was mismatched with Frankfort plane in 84% of the sample with a range of 19°. The true vertical plane is adequate for measuring lower incisor inclination. Sociedad Argentina de Investigación Odontológica.

  17. Influence of rotating in-plane field on vertical Bloch lines in the walls of second kind of dumbbell domains

    NASA Astrophysics Data System (ADS)

    Sun, H. Y.; Hu, H. N.; Sun, Y. P.; Nie, X. F.

    2004-08-01

    Influence of rotating in-plane field on vertical Bloch lines in the walls of second kind of dumbbell domains (IIDs) was investigated, and a critical in-plane field range [ Hip1, Hip2] of which vertical-Bloch lines (VBLs) annihilated in IIDs is found under rotating in-plane field ( Hip1 is the maximal critical in-plane-field of which hard domains remain stable, Hip2 is the minimal critical in-plane-field of which all of the hard domains convert to soft bubbles (SBs, without VBLs)). It shows that the in-plane field range [ Hip1, Hip2] changes with the change of the rotating angle Δ ϕ. Hip1 maintains stable, while Hip2 decreases with the decreasing of rotating angle Δ ϕ. Comparing it with the spontaneous shrinking experiment of IIDs under both bias field and in-plane field, we presume that under the application of in-plane field there exists a direction along which the VBLs in the domain walls annihilate most easily, and it is in the direction that domain walls are perpendicular to the in-plane field.

  18. Neural control of arm movements reveals a tendency to use gravity to simplify joint coordination rather than to decrease muscle effort.

    PubMed

    Wang, Wanyue; Dounskaia, Natalia

    2016-12-17

    How gravity influences neural control of arm movements remains under debate. We tested three alternative interpretations suggested by previous research: (1) that muscular control includes two components, tonic which compensates for gravity and phasic which produces the movement; (2) that there is a tendency to exploit gravity to reduce muscle effort; and (3) that there is a tendency to use a trailing pattern of joint control during which either the shoulder or elbow is rotated actively and the other joint rotates predominantly passively, and to exploit gravity for control of the passively rotated joint. A free-stroke drawing task was performed that required production of center-out strokes within a circle while selecting stroke directions randomly. The circle was positioned in the horizontal, sagittal, and frontal plane. The arm joints freely rotated in space. In each plane, the distribution of the strokes across directions was non-uniform. Directional histograms were built and their peaks were used to identify preferred movement directions. The directional preferences were especially pronounced in the two vertical planes. The upward directions were most preferred. To test the three interpretations, we used a kinetic analysis that determined the role of gravitational torque in the production of movement in the preferred directions. The results supported the third interpretation and provided evidence against the first and second interpretation. The trailing pattern has been associated with reduced neural effort for joint coordination, and therefore, we conclude that the major tendency with respect to gravity is to exploit it for simplification of joint coordination. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  19. Customized Interactive Robotic Treatment for Stroke: EMG-Triggered Therapy

    PubMed Central

    Dipietro, Laura; Ferraro, Mark; Palazzolo, Jerome Joseph; Krebs, Hermano Igo; Volpe, Bruce T.; Hogan, Neville

    2009-01-01

    A system for electromyographic (EMG) triggering of robot-assisted therapy (dubbed the EMG game) for stroke patients is presented. The onset of a patient’s attempt to move is detected by monitoring EMG in selected muscles, whereupon the robot assists her or him to perform point-to-point movements in a horizontal plane. Besides delivering customized robot-assisted therapy, the system can record signals that may be useful to better understand the process of recovery from stroke. Preliminary experiments aimed at testing the proposed system and gaining insight into the potential of EMG-triggered, robot-assisted therapy are reported. PMID:16200756

  20. Determining the wedge angle and optical homogeneity of a glass plate by statistically analyzing the deformation in the wavefront surface.

    PubMed

    Yang, Pao-Keng

    2017-08-01

    By using a light-emitting diode as the probing light source and a Shack-Hartmann wavefront sensor as the recorder for the wavefront surface to execute a relative measurement, we present a useful method for determining the small wedge angle and optical homogeneity of a nominally planar glass plate from the wavefront measurements. The measured wavefront surface from the light source was first calibrated to be a horizontal plane before the plate under test was inserted. The wedge angle of the plate can be determined from the inclining angle of the regression plane of the measured wavefront surface after the plate was inserted between the light source and the wavefront sensor. Despite the annoying time-dependent altitude fluctuation in measured wavefront topography, the optical homogeneity of the plate can be estimated from the increment on the average variance of the wavefront surface to its regression plane after the light passes through it by using the Bienaymé formula.

  1. Stagger angle dependence of inertial and elastic coupling in bladed disks

    NASA Technical Reports Server (NTRS)

    Crawley, E. F.; Mokadam, D. R.

    1984-01-01

    Conditions which necessitate the inclusion of disk and shaft flexibility in the analysis of blade response in rotating blade-disk-shaft systems are derived in terms of nondimensional parameters. A simple semianalytical Rayleigh-Ritz model is derived in which the disk possesses all six rigid body degrees of freedom, which are elastically constrained by the shaft. Inertial coupling by the rigid body motion of the disk on a flexible shaft and out-of-plane elastic coupling due to disk flexure are included. Frequency ratios and mass ratios, which depend on the stagger angle, are determined for three typical rotors: a first stage high-pressure core compressor, a high bypass ratio fan, and an advanced turboprop. The stagger angle controls the degree of coupling in the blade-disk system. In the blade-disk-shaft system, the stagger angle determines whether blade-disk motion couples principally to the out-of-plane or in-plane motion of the disk on the shaft. The Ritz analysis shows excellent agreement with experimental results.

  2. The effect of canard leading edge sweep and dihedral angle on the longitudinal and lateral aerodynamic characteristic of a close-coupled canard-wing configuration

    NASA Technical Reports Server (NTRS)

    Gloss, B. B.

    1974-01-01

    A generalized wind-tunnel model, with canard and wing planforms typical of highly maneuverable aircraft, was tested in the Langley high-speed 7- by 10-foot tunnel at a Mach number of 0.30. The test was conducted in order to determine the effects of canard sweep and canard dihedral on canard-wing interference at high angles of attack. In general, the effect of canard sweep on lift is small up to an angle of attack of 16 deg. However, for angles of attack greater than 16 deg, an increase in the canard sweep results in an increase in lift developed by the canard when the canard is above or in the wing chord plane. This increased lift results in a lift increase for the total configuration for the canard above the wing chord plane. For the canard in the wing chord plane, the increased canard lift is partially lost by increased interference on the wing.

  3. Loading differences in single-leg landing in the forehand- and backhand-side courts after an overhead stroke in badminton: A novel tri-axial accelerometer research.

    PubMed

    Sasaki, Shogo; Nagano, Yasuharu; Ichikawa, Hiroshi

    2018-05-10

    Anterior cruciate ligament (ACL) injuries in badminton commonly occur during single-leg landing after an overhead stroke in the backhand-side court. This study compared differences in trunk acceleration and kinematic variables during single-leg landing in the forehand- and backhand-side courts after an overhead stroke. Eighteen female junior badminton players performed two singles games while wearing a tri-axial accelerometer. The moment that over 4g of resultant acceleration was generated was determined using synchronised video cameras. Trunk lateral inclination and hip abduction angles at the point of landing with over 4g of resultant acceleration were analysed. Mediolateral acceleration in the backhand-side court was greater than that in the opposite-side court (p < 0.001, ES = 0.840). Both trunk lateral angles were larger than those previously reported in injured participants and the hip abduction angle in the backhand-side court was larger than that in the forehand-side court (p < 0.001, ES = 2.357). The lateral and vertical acceleration in the backhand-side court showed moderate-to-strong correlations with the trunk and hip angles. The mediolateral physical demand and high-risk posture in the backhand-side court may be associated with a higher incidence of knee injuries during badminton games.

  4. MPI CyberMotion Simulator: implementation of a novel motion simulator to investigate multisensory path integration in three dimensions.

    PubMed

    Barnett-Cowan, Michael; Meilinger, Tobias; Vidal, Manuel; Teufel, Harald; Bülthoff, Heinrich H

    2012-05-10

    Path integration is a process in which self-motion is integrated over time to obtain an estimate of one's current position relative to a starting point (1). Humans can do path integration based exclusively on visual (2-3), auditory (4), or inertial cues (5). However, with multiple cues present, inertial cues - particularly kinaesthetic - seem to dominate (6-7). In the absence of vision, humans tend to overestimate short distances (<5 m) and turning angles (<30°), but underestimate longer ones (5). Movement through physical space therefore does not seem to be accurately represented by the brain. Extensive work has been done on evaluating path integration in the horizontal plane, but little is known about vertical movement (see (3) for virtual movement from vision alone). One reason for this is that traditional motion simulators have a small range of motion restricted mainly to the horizontal plane. Here we take advantage of a motion simulator (8-9) with a large range of motion to assess whether path integration is similar between horizontal and vertical planes. The relative contributions of inertial and visual cues for path navigation were also assessed. 16 observers sat upright in a seat mounted to the flange of a modified KUKA anthropomorphic robot arm. Sensory information was manipulated by providing visual (optic flow, limited lifetime star field), vestibular-kinaesthetic (passive self motion with eyes closed), or visual and vestibular-kinaesthetic motion cues. Movement trajectories in the horizontal, sagittal and frontal planes consisted of two segment lengths (1st: 0.4 m, 2nd: 1 m; ±0.24 m/s(2) peak acceleration). The angle of the two segments was either 45° or 90°. Observers pointed back to their origin by moving an arrow that was superimposed on an avatar presented on the screen. Observers were more likely to underestimate angle size for movement in the horizontal plane compared to the vertical planes. In the frontal plane observers were more likely to overestimate angle size while there was no such bias in the sagittal plane. Finally, observers responded slower when answering based on vestibular-kinaesthetic information alone. Human path integration based on vestibular-kinaesthetic information alone thus takes longer than when visual information is present. That pointing is consistent with underestimating and overestimating the angle one has moved through in the horizontal and vertical planes respectively, suggests that the neural representation of self-motion through space is non-symmetrical which may relate to the fact that humans experience movement mostly within the horizontal plane.

  5. Influence of magnification and superimposition of structures on cephalometric diagnosis.

    PubMed

    Paula, Leonardo Koerich de; Solon-de-Mello, Priscilla de Almeida; Mattos, Claudia Trindade; Ruellas, Antônio Carlos de Oliveira; Sant'Anna, Eduardo Franzotti

    2015-01-01

    The purpose of this study was to assess the influence of magnification and superimposition of structures on CBCT-generated lateral cephalometric radiographs (LCR) using different segments of the cranium. CBCT scans of 10 patients were selected. Four LCR were generated using Dolphin Imaging(r) software: full-face, right side, left side and center of the head. A total of 40 images were imported into Radiocef Studio 2(r), and the angles of the most common cephalometric analyses were traced by the same observer twice and within a 10-day interval. Statistical analyses included intraexaminer agreement and comparison between methods by means of intraclass correlation coefficient (ICC) and Bland-Altman agreement tests. Intraexaminer agreement of the angles assessed by ICC was excellent (> 0.90) for 83% of measurements, good (between 0.75 and 0.90) for 15%, and moderate (between 0.50 and 0.75) for 2% of measurements. The comparison between methods by ICC was excellent for 68% of measurements, good for 26%, and moderate for 6%. Variables presenting wider confidence intervals (> 6o) in the Bland-Altman tests, in intraexaminer assessment, were: mandibular incisor angle, maxillary incisor angle, and occlusal plane angle. And in comparison methods the variables with wider confidence interval were: mandibular incisor, maxillary incisor, GoGn, occlusal plane angle, Frankfort horizontal plane (FHP), and CoA. Superimposition of structures seemed to influence the results more than magnification, and neither one of them significantly influenced the measurements. Considerable individual variability may occur, especially for mandibular and maxillary incisors, FHP and occlusal plane.

  6. Aerodynamic forces and flow structures of the leading edge vortex on a flapping wing considering ground effect.

    PubMed

    Van Truong, Tien; Byun, Doyoung; Kim, Min Jun; Yoon, Kwang Joon; Park, Hoon Cheol

    2013-09-01

    The aim of this work is to provide an insight into the aerodynamic performance of the beetle during takeoff, which has been estimated in previous investigations. We employed a scaled-up electromechanical model flapping wing to measure the aerodynamic forces and the three-dimensional flow structures on the flapping wing. The ground effect on the unsteady forces and flow structures were also characterized. The dynamically scaled wing model could replicate the general stroke pattern of the beetle's hind wing kinematics during takeoff flight. Two wing kinematic models have been studied to examine the influences of wing kinematics on unsteady aerodynamic forces. In the first model, the angle of attack is asymmetric and varies during the translational motion, which is the flapping motion of the beetle's hind wing. In the second model, the angle of attack is constant during the translational motion. The instantaneous aerodynamic forces were measured for four strokes during the beetle's takeoff by the force sensor attached at the wing base. Flow visualization provided a general picture of the evolution of the three-dimensional leading edge vortex (LEV) on the beetle hind wing model. The LEV is stable during each stroke, and increases radically from the root to the tip, forming a leading-edge spiral vortex. The force measurement results show that the vertical force generated by the hind wing is large enough to lift the beetle. For the beetle hind wing kinematics, the total vertical force production increases 18.4% and 8.6% for the first and second strokes, respectively, due to the ground effect. However, for the model with a constant angle of attack during translation, the vertical force is reduced during the first stroke. During the third and fourth strokes, the ground effect is negligible for both wing kinematic patterns. This finding suggests that the beetle's flapping mechanism induces a ground effect that can efficiently lift its body from the ground during takeoff.

  7. Feasibility and efficacy of wearable devices for upper limb rehabilitation in patients with chronic stroke: a randomized controlled pilot study.

    PubMed

    Lin, Li-Fong; Lin, Yi-Jia; Lin, Zi-Hao; Chuang, Li-Yun; Hsu, Wei-Chun; Lin, Yuan-Hsiang

    2017-06-19

    Wearable devices based on inertial measurement units through wireless sensor networks have many applications such as real-time motion monitoring and functional outcome assessment of stroke rehabilitation. However, additional investigations are warranted to validate their clinical value, particularly in detecting the synergy patterns of movements after stroke. To explore the feasibility and efficacy of wearable devices for upper limb rehabilitation in patients with chronic stroke and to compare the intervention effects (e.g., neurological recovery, active range of motion, and deviation angle) with those in a control group. A single-blind, randomized-controlled pilot study. Rehabilitation ward. A total of 18 patients with chronic stroke were randomly distributed into a device group and control group. Both groups received conventional rehabilitation; nevertheless, the device group was additionally subjected to 15 daily sessions at least three times a week for 5 weeks. The outcome measures included the upper extremity subscores of the Fugl-Meyer assessment, active range of motion, and deviation angle. These measurements were performed pre- and post-treatment. All five Fugl-Meyer assessment subscores improved in both the device and control groups after intervention; in particular, the "shoulder/elbow/forearm" subscore (p = 0.02, 0.03) and "total score" (p = 0.03, 0.03) substantially improved. The active range of motion of shoulder flexion and abduction substantially improved at pre-post treatment in both the device (p = 0.02, 0.03) and control (p = 0.02, 0.03) groups. The deviation angle of shoulder external rotation during shoulder abduction substantially improved in the device group (p = 0.02), but not in the control group. The designed wearable devices are practical and efficient for use in chronic patients with stroke. Wearable devices are expected to be useful for future internet-of-things rehabilitation clinical trials at home and in long-term care institutions.

  8. Carpet cloak with graded dielectric metasurface (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Hsu, LiYi; Lepetit, Thomas; Kante, Boubacar

    2015-09-01

    We demonstrate a method to hide a Gaussian-shaped bump on a ground plane from an incoming plane wave. In essence, we use a graded metasurface to shape the wavefronts like those of a flat ground plane[1,2].The metasurface provides additional phase to the electromagnetic field to control the reflection angle. To mimic a flat ground plane, the reflection angle is chosen to be equal to the incident angle. The desired phase distribution is calculated based on generalized Snell's laws[3]. We design our metasurface in the microwave range using sub-wavelength dielectric resonators. We verify the design by full-wave time-domain simulations and show that the result matches our theory well. This approach can be applied to hide any object on a ground plane not only at microwave frequencies but also at higher frequencies up to the infrared. 1. Jensen Li and J. B. Pendry, Hiding under the Carpet: A New Strategy for Cloaking. Phys. Rev. Lett. 101, 203901 (2008) 2. Andrea Alu, Mantle cloak: Invisibility induced by a surface. Phys. Rev. B 80, 245115 (2009) 3. Yu N, et al. Light propagation with phase discontinuities: Generalized laws of reflection and refraction. Science 334(6054):333-337 (2011)

  9. Kinematic analysis of head, trunk, and pelvic motion during mirror therapy for stroke patients

    PubMed Central

    Kim, Jinmin; Yi, Jaehoon; Song, Chang-Ho

    2017-01-01

    [Purpose] The purpose of this study was to investigate mirror therapy (MT) condition by analyzing kinematic parameters according to mirror size and angle. [Subjects and Methods] Three hemiparesis stroke patients and five healthy adults participated in this cross-sectional study. Kinematic parameters during the MT were collected over a total of 5 trials for each subject (3 mirror angles × 3 mirror sizes). Center of pressure (COP) excursion data was collected by force plate, and other kinematic parameters by infra-red cameras. [Results] The larger the size and smaller the angle, the overall dependent variables decreased in all participants. Particularly, when virtual reality reflection equipment (VRRE) was used, the value of the flexion and the lateral tilt was the closest to the midline compared to all other independent variables. Moreover, it showed tendency of moving towards the affected side. Based on the results, MT for stroke patients has a disadvantage of shifting weight and leaning towards the unaffected side during therapy. [Conclusion] Therefore, it seems to be more effective in terms of clinics to apply VRRE to make up for the weak parts and provide more elaborate visual feedback. PMID:29184290

  10. Kinematic analysis of head, trunk, and pelvic motion during mirror therapy for stroke patients.

    PubMed

    Kim, Jinmin; Yi, Jaehoon; Song, Chang-Ho

    2017-10-01

    [Purpose] The purpose of this study was to investigate mirror therapy (MT) condition by analyzing kinematic parameters according to mirror size and angle. [Subjects and Methods] Three hemiparesis stroke patients and five healthy adults participated in this cross-sectional study. Kinematic parameters during the MT were collected over a total of 5 trials for each subject (3 mirror angles × 3 mirror sizes). Center of pressure (COP) excursion data was collected by force plate, and other kinematic parameters by infra-red cameras. [Results] The larger the size and smaller the angle, the overall dependent variables decreased in all participants. Particularly, when virtual reality reflection equipment (VRRE) was used, the value of the flexion and the lateral tilt was the closest to the midline compared to all other independent variables. Moreover, it showed tendency of moving towards the affected side. Based on the results, MT for stroke patients has a disadvantage of shifting weight and leaning towards the unaffected side during therapy. [Conclusion] Therefore, it seems to be more effective in terms of clinics to apply VRRE to make up for the weak parts and provide more elaborate visual feedback.

  11. Correlation of Beta Angle with Antero-Posterior Dysplasia Indicators and FMA: An Institution Based Cephalometric Study.

    PubMed

    Singh, Gurinder; Verma, Sanjeev; Singh, Devinder Preet; Yadav, Sumit Kumar; Yadav, Achla Bharti

    2016-11-01

    Beta angle utilizes three skeletal landmarks - point A, point B, and point C (the apparent axis of the condyle). It is formed between A-B line and point A perpendicular to C-B line. Further this angle indicates the severity and the type of skeletal dysplasia in the sagittal dimension and it changes with the growth pattern of the patient. Hence, it is important to study the dependence of beta angle on the growth pattern. The present study was designed to evaluate the correlation of Beta angle with point A-Nasion-point B (ANB) angle, points A and B to palatal plane (App-Bpp), Wit's appraisal and Maxillary-Mandibular plane angle Bisector (MMB) and Frankfort-Mandibular plane Angle (FMA) in Skeletal Class I, Class II and Class III malocclusion groups. Pre-treatment lateral head cephalo-grams of 120 subjects in age group of 15-25 years were obtained. Three skeletal Class I, Class II and Class III malocclusion groups (40 each) were assorted on the basis of ANB, MMB, App-Bpp, Wit's appraisal and FMA. Analysis of variance (ANOVA) and mean differences were calculated to compare the study groups. Bivariate correlations among different parameters of these groups were obtained. Normal values of beta angle in skeletal Class I group, skeletal Class II group and skeletal Class III group was 31.33±3.25, 25.28±4.28 and 40.93±4.55 respectively. Overall beta angle showed a strong correlation with all parameters of anterio-posterior dysplasia indicators except FMA. Beta angle shows weak correlation with FMA and is not affected by growth pattern/jaw rotation. The normal values are in same range irrespective of the differences in craniofacial morphology.

  12. Correlation of Beta Angle with Antero-Posterior Dysplasia Indicators and FMA: An Institution Based Cephalometric Study

    PubMed Central

    Singh, Gurinder; Verma, Sanjeev; Singh, Devinder Preet; Yadav, Achla Bharti

    2016-01-01

    Introduction Beta angle utilizes three skeletal landmarks – point A, point B, and point C (the apparent axis of the condyle). It is formed between A-B line and point A perpendicular to C-B line. Further this angle indicates the severity and the type of skeletal dysplasia in the sagittal dimension and it changes with the growth pattern of the patient. Hence, it is important to study the dependence of beta angle on the growth pattern. Aim The present study was designed to evaluate the correlation of Beta angle with point A–Nasion–point B (ANB) angle, points A and B to palatal plane (App-Bpp), Wit’s appraisal and Maxillary-Mandibular plane angle Bisector (MMB) and Frankfort-Mandibular plane Angle (FMA) in Skeletal Class I, Class II and Class III malocclusion groups. Materials and Methods Pre-treatment lateral head cephalo-grams of 120 subjects in age group of 15-25 years were obtained. Three skeletal Class I, Class II and Class III malocclusion groups (40 each) were assorted on the basis of ANB, MMB, App-Bpp, Wit’s appraisal and FMA. Analysis of variance (ANOVA) and mean differences were calculated to compare the study groups. Bivariate correlations among different parameters of these groups were obtained. Results Normal values of beta angle in skeletal Class I group, skeletal Class II group and skeletal Class III group was 31.33±3.25, 25.28±4.28 and 40.93±4.55 respectively. Overall beta angle showed a strong correlation with all parameters of anterio-posterior dysplasia indicators except FMA. Conclusion Beta angle shows weak correlation with FMA and is not affected by growth pattern/jaw rotation. The normal values are in same range irrespective of the differences in craniofacial morphology. PMID:28050509

  13. Spatial orientation of semicircular canals and afferent sensitivity vectors in pigeons

    NASA Technical Reports Server (NTRS)

    Dickman, J. D.

    1996-01-01

    Rotational head motion in vertebrates is detected by the semicircular canal system, whose innervating primary afferent fibers carry information about movement in specific head planes. The semicircular canals have been qualitatively examined over a number of years, and the canal planes have been quantitatively characterized in several animal species. The present study first determined the geometric relationship between individual semicircular canals and between the canals and the stereotactic head planes in pigeons. Stereotactic measurements of multiple points along the circumference of the bony canals were taken, and the measured points fitted with a three-dimensional planar surface. Direction normals to the plane's surface were calculated and used to define angles between semicircular canal pairs. Because of the unusual shape of the anterior semicircular canals in pigeons, two planes, a major and a minor, were fitted to the canal's course. Calculated angle values for all canals indicated that the horizontal and posterior semicircular canals are nearly orthogonal, but the anterior canals have substantial deviations from orthogonality with other canal planes. Next, the responses of the afferent fibers that innervate each of the semicircular canals to 0.5 Hz sinusoidal rotation about an earth-vertical axis were obtained. The head orientation relative to the rotation axis was systematically varied so that directions of maximum sensitivity for each canal afferent could be determined. These sensitivity vectors were then compared with the canal plane direction normals. The afferents that innervated specific semicircular canals formed homogeneous clusters of sensitivity vectors in different head planes. The horizontal and posterior afferents had average sensitivity vectors that were largely co-incident with the innervated canal plane direction normals. Anterior canal afferents, however, appeared to synthesize contributions from the major and minor plane components of the bony canal structure to produce a resultant sensitivity vector that was positioned between the canal planes. Calculated angles between the average canal afferent sensitivity vectors revealed that direction orthogonality is preserved at the afferent signal level, even though deviations from canal plane orthogonality exist.

  14. 2-({4-[4-(1H-Benzimidazol-2-yl)phen­yl]-1H-1,2,3-triazol-1-yl}meth­oxy)ethanol

    PubMed Central

    Ouahrouch, Abdelaaziz; Taourirte, Moha; Lazrek, Hassan B.; Bats, Jan W.; Engels, Joachim W.

    2012-01-01

    In the title molecule, C18H17N5O2, the dihedral angle between the benzene plane and the benzimidazole plane is 19.8 (1)° and the angle between the benzene plane and the triazole plane is 16.7 (1)°. In the crystal, mol­ecules are connected by O—H⋯N hydrogen bonds, forming zigzag chains along the c-axis direction. The chains are connected by bifurcated N—H⋯(N,N) hydrogen bonds into layers parallel to (100). These layers are connected along the a-axis direction by weak C—H⋯O contacts, forming a three-dimensional network. PMID:22719663

  15. Ethyl 2-(1,2,3,4-tetrahydro­spiro­[carba­zole-3,2′-[1,3]dioxolan]-9-yl)acetate

    PubMed Central

    Löffler, Philipp M. G.; Ulven, Trond; Bond, Andrew D.

    2009-01-01

    In the title compound, C18H21NO4, the hydrogenated six-membered ring of the carbazole unit adopts a half-chair conformation. The dioxolane ring and ethyl­acetate substituent point to opposite sides of the carbazole plane. The ethyl­acetate substituent adopts an essentially fully extended conformation, and its mean plane forms a dihedral angle of 83.8 (1)° with respect to the carbazole mean plane. The mol­ecules are arranged into stacks in which the carbazole planes form a dihedral angle of 4.4 (1)° and have an approximate inter­planar separation of 3.6 Å. PMID:21582427

  16. Sagittal and transversal plane deformity in thoracic scoliosis.

    PubMed

    Kotwicki, Tomasz

    2002-01-01

    The aim of the study was to assess the sagittal and transversal plane deformity of the spine in thoracic scoliosis by the mean of 3-D radiographic analysis. 46 patients admitted for surgery for thoracic idiopathic scoliosis underwent preoperative radiographic assessment. All patients presented the same pattern of the coronal plane deformity: single right thoracic curve (Lenke 1, King 3). Neither lumbar nor proximal thoracic structural curve were present. The Cobb angle varied from 41gamma to 77 gamma (mean 55,4 gamma +/- 8,6 gamma). Long cassette standing antero-posterior and lateral radiographs were analysed. Three-dimensional reconstruction with Rachis 91TM software was performed for each pair of radiographs. The following parameters were assessed: sagittal thoracic Cobb angle (Th4-Th12), upper thoracic kyphosis angle (Th5-Th8), lower thoracic kyphosis angle (Th9-Th12), superior and inferior hemi-curve sagittal angles, lumbar lordosis, sacral slope, sacral incidence, vertebral plate index, segmental vertebral axial rotation throughout the thoracic and lumbar spine. Results showed great variability of parameters assessed. The non-harmonious distribution of kyphosis was demonstrated in the thoracic spine. Local Th9-Th12 hypokyphosis and adjacent local Th5-Th8 hyperkyphosis constitute the most typical sagittal pathologies. So called normokyphotic curves were composed of one hyperkyphotic and one hypokyphotic zone. Th1-Th4 segment revealed two patterns of segmental rotation distribution: a purely compensatory curve with no vertebral axial rotation or a rotated curve presenting the morphology intermediate between Lenke 1 and Lenke 2 types (or King 3 and King 5). curves presenting the same coronal plane deformity differ in their morphology assessed in the two other planes; global thoracic kyphosis angle is a misleading parameter because it covers hypo- and hyperkyphotic zones; local distal thoracic (Th9-Th12) hypokyphosis is present in idiopathic thoracic scoliosis.

  17. Association between masticatory performance using a colour-changeable chewing gum and jaw movement.

    PubMed

    Komagamine, Y; Kanazawa, M; Minakuchi, S; Uchida, T; Sasaki, Y

    2011-08-01

    The purpose of this study was to investigate the relationship between masticatory performance as determined using a colour-changeable chewing gum and mandibular movements. Subjects comprised 45 fully dentate adults (23 men, 22 women; mean age, 28·1 years). The gum was chewed for a specified number of chewing strokes (20, 40, 60, 80, 120 or 160 strokes) without any instructions as to chewing side. A colourimeter was used to measure L*, a* and b* values (CIE-L*a*b* colour system) for the chewed gum, then the difference between two colours in the CIE-L*a*b* colour space (ΔE) for each number of chewing strokes was calculated according to a formula. Index of masticatory performance (ΔE60) for each subject was obtained using ΔE for 20, 40, 60, 80, 120 and 160 strokes. Mandibular movements were recorded using an opto-electric system with six degrees of freedom. Twelve parameters of mandibular movements relating to amplitude, duration, velocity and angle were computed for each cycle, and mean values for 10 cycles (from cycle 11 to 20) were calculated separately. Stepwise multiple regression analysis identified maximum closing velocity and closing angle as predictors accounting for 18% of the variation in ΔE60. These results suggest that lower angles of approach to intercuspation and faster speed during closing duration are associated with colour changes in the colour-changeable chewing gum. © 2011 Blackwell Publishing Ltd.

  18. Vibration-Assisted Femtosecond Laser Drilling with Controllable Taper Angles for AMOLED Fine Metal Mask Fabrication

    PubMed Central

    Choi, Wonsuk; Kim, Hoon Young; Jeon, Jin Woo; Chang, Won Seok; Cho, Sung-Hak

    2017-01-01

    This study investigates the effect of focal plane variation using vibration in a femtosecond laser hole drilling process on Invar alloy fabrication quality for the production of fine metal masks (FMMs). FMMs are used in the red, green, blue (RGB) evaporation process in Active Matrix Organic Light-Emitting Diode (AMOLED) manufacturing. The taper angle of the hole is adjusted by attaching the objective lens to a micro-vibrator and continuously changing the focal plane position. Eight laser pulses were used to examine how the hole characteristics vary with the first focal plane’s position, where the first pulse is focused at an initial position and the focal planes of subsequent pulses move downward. The results showed that the hole taper angle can be controlled by varying the amplitude of the continuously operating vibrator during femtosecond laser hole machining. The taper angles were changed between 31.8° and 43.9° by adjusting the vibrator amplitude at a frequency of 100 Hz. Femtosecond laser hole drilling with controllable taper angles is expected to be used in the precision micro-machining of various smart devices. PMID:28772571

  19. A Study of a Mini-Drift GEM Tracking Detector

    NASA Astrophysics Data System (ADS)

    Azmoun, B.; DiRuzza, B.; Franz, A.; Kiselev, A.; Pak, R.; Phipps, M.; Purschke, M. L.; Woody, C.

    2016-06-01

    A GEM tracking detector with an extended drift region has been studied as part of an effort to develop new tracking detectors for future experiments at RHIC and for the Electron Ion Collider that is being planned for BNL or JLAB. The detector consists of a triple GEM stack with a 1.6 cm drift region that was operated in a mini TPC type configuration. Both the position and arrival time of the charge deposited in the drift region were measured on the readout plane which allowed the reconstruction of a short vector for the track traversing the chamber. The resulting position and angle information from the vector could then be used to improve the position resolution of the detector for larger angle tracks, which deteriorates rapidly with increasing angle for conventional GEM tracking detectors using only charge centroid information. Two types of readout planes were studied. One was a COMPASS style readout plane with 400 μm pitch XY strips and the other consisted of 2 × 10 mm2 chevron pads. The detector was studied in test beams at Fermilab and CERN, along with additional measurements in the lab, in order to determine its position and angular resolution for incident track angles up to 45 degrees. Several algorithms were studied for reconstructing the vector using the position and timing information in order to optimize the position and angular resolution of the detector for the different readout planes. Applications for large angle tracking detectors at RHIC and EIC are also discussed.

  20. Light extinction method on high-pressure diesel injection

    NASA Astrophysics Data System (ADS)

    Su, Tzay-Fa; El-Beshbeeshy, Mahmound S.; Corradini, Michael L.; Farrell, Patrick V.

    1995-09-01

    A two dimensional optical diagnostic technique based on light extinction was improved and demonstrated in an investigation of diesel spray characteristics at high injection pressures. Traditional light extinction methods require the spray image to be perpendicular to the light path. In the improved light extinction scheme, a tilted spray image which has an angle with the light path is still capable of being processed. This technique utilizes high speed photography and digital image analysis to obtain qualitative and quantitative information of the spray characteristics. The injection system used was an electronically controlled common rail unit injector system with injection pressures up to 100 MPa. The nozzle of the injector was a mini-sac type with six holes on the nozzle tip. Two different injection angle nozzles, 125 degree(s) and 140 degree(s), producing an in-plane tilted spray and an out of plane tilted spray were investigated. The experiments were conducted on a constant volume spray chamber with the injector mounted tilted at an angle of 62.5 degree(s)$. Only one spray plume was viewed, and other sprays were free to inject to the chamber. The spray chamber was pressurized with argon and air under room temperature to match the combustion chamber density at the start of the injection. The experimental results show that the difference in the spray tip penetration length, spray angle, and overall average Sauter mean diameter is small between the in- plane tilted spray and the out of plane tilted spray. The results also show that in-plane tilted spray has a slightly larger axial cross- section Sauter mean diameter than the out of plane tilted spray.

  1. Testing of a variable-stroke Stirling engine

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.; Allen, David J.

    1986-01-01

    Testing of a variable-stroke Stirling engine at NASA Lewis has been completed. In support of the DOE Stirling Engine Highway Vehicle Systems Program, the engine was tested for about 70 hours total with both He and H2 as working fluids over a range of pressures and strokes. A direct comparison was made of part-load efficiencies obtained with variable-stroke (VS) and variable-pressure operation. Two failures with the variable-angle swash-plate drive system limited testing to low power levels. These failures are not thought to be caused by problems inherent with the VS concept but do emphasize the need for careful design in the area of the crossheads.

  2. Testing of a variable-stroke Stirling engine

    NASA Technical Reports Server (NTRS)

    Thieme, L. G.; Allen, D. J.

    1986-01-01

    Testing of a variable-stroke Stirling engine at NASA Lewis has been completed. In support of the DOE Stirling Engine Highway Vehicle Systems Program, the engine was tested for about 70 hours total with both He and H2 working fluids over a range of pressures and strokes. A direct comparison was made of part-load efficiencies obtained with variable-stroke (VS) and variable-pressure operation. Two failures with the variable-angle swash-plate drive system limited testing to low power levels. These failures are not thought to be caused by problems inherent with the VS concept but do emphasize the need for careful design in the area of the crossheads.

  3. Motion of a carrier with a mobile load along a rough inclined plane

    NASA Astrophysics Data System (ADS)

    Bilchenko, G. G.

    2018-03-01

    The mechanical system consisting of a carrier and a load is considered. The load can move respectively the carrier according to the preset given motion law. The carrier motion from rest caused the load motion is investigated. The carrier can move translationally along rectilinear trajectory along rough inclined plane. The trajectory is the line of the greatest descent. The axis of rectilinear channel along which the load moves is situated in vertical plane containing the carrier trajectory. The Coulomb model is taken to describe the friction forces on sloped plane. Differential equations of motion of carrier with load are obtained. The sufficient condition of the carrier motion without detachment from inclined plane is given. For two special cases of the channel installation angle and the plane inclination angle combination the motion types are described. The computation experiments results are presented: the carrier motions in the special cases are illustrated, the phase portraits for some types of motions are constructed.

  4. The craniofacial complex in 47, XXX females.

    PubMed

    Krusinskiene, Viktorija; Krusinskie, Viktorija; Alvesalo, Lassi; Sidlauskas, Antanas

    2005-08-01

    A study of the craniofacial complex in four 47, XXX Finnish females, or females with an extra X chromosome, was carried out using cephalometric analysis comprising linear and angular measurements. The lengths of the anterior and posterior cranial bases, the calvarium, mandibular ramus and posterior and upper anterior face heights were found to be significantly shorter than in female controls, while the angles between the foraminal and clival planes, the mandibular plane and cranial base, the maxillary and occlusal planes, the maxillary and mandibular planes and the foraminal and mandibular planes, and also the gonial angle, were significantly enlarged. The present findings of reduced linear measurements, together with the results of studies on the craniofacial complex of 47, XXY and 47, XYY males, suggest dimensional variation between these groups from the promoting effect of an extra Y chromosome and the retarding effect of an extra X chromosome on craniofacial growth.

  5. Three-parameter error analysis method based on rotating coordinates in rotating birefringent polarizer system

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

    Cao, Junjie; Jia, Hongzhi, E-mail: hzjia@usst.edu.cn

    2015-11-15

    We propose error analysis using a rotating coordinate system with three parameters of linearly polarized light—incidence angle, azimuth angle on the front surface, and angle between the incidence and vibration planes—and demonstrate the method on a rotating birefringent prism system. The transmittance and angles are calculated plane-by-plane using a birefringence ellipsoid model and the final transmitted intensity equation is deduced. The effects of oblique incidence, light interference, beam convergence, and misalignment of the rotation and prism axes are discussed. We simulate the entire error model using MATLAB and conduct experiments based on a built polarimeter. The simulation and experimental resultsmore » are consistent and demonstrate the rationality and validity of this method.« less

  6. Vectorial point spread function and optical transfer function in oblique plane imaging.

    PubMed

    Kim, Jeongmin; Li, Tongcang; Wang, Yuan; Zhang, Xiang

    2014-05-05

    Oblique plane imaging, using remote focusing with a tilted mirror, enables direct two-dimensional (2D) imaging of any inclined plane of interest in three-dimensional (3D) specimens. It can image real-time dynamics of a living sample that changes rapidly or evolves its structure along arbitrary orientations. It also allows direct observations of any tilted target plane in an object of which orientational information is inaccessible during sample preparation. In this work, we study the optical resolution of this innovative wide-field imaging method. Using the vectorial diffraction theory, we formulate the vectorial point spread function (PSF) of direct oblique plane imaging. The anisotropic lateral resolving power caused by light clipping from the tilted mirror is theoretically analyzed for all oblique angles. We show that the 2D PSF in oblique plane imaging is conceptually different from the inclined 2D slice of the 3D PSF in conventional lateral imaging. Vectorial optical transfer function (OTF) of oblique plane imaging is also calculated by the fast Fourier transform (FFT) method to study effects of oblique angles on frequency responses.

  7. Effects of excimer laser illumination on microdrilling into an oblique polymer surface

    NASA Astrophysics Data System (ADS)

    Wu, Chih-Yang; Shu, Chun-Wei; Yeh, Zhi-Chang

    2006-08-01

    In this work, we present the experimental results of micromachining into polymethy-methacrylate exposed to oblique KrF excimer laser beams. The results of low-aspect-ratio ablations show that the ablation rate decreases monotonously with the increase of incident angle for various fluences. The ablation rate of high-aspect-ratio drilling with opening center on the focal plane is almost independent of incident angles and is less than that of low-aspect-ratio ablation. The results of high-aspect-ratio ablations show that the openings of the holes at a distance from the focal plane are enlarged and their edges are blurred. Besides, the depth of a hole in the samples oblique to the laser beam at a distance from the focal plane decreases with the increase of the distance from the focal plane. The number of deep holes generated by oblique laser beams through a matrix of apertures decreases with the increase of incident angle. Those phenomena reveal the influence of the local light intensity on microdrilling into an oblique surface.

  8. The Nimbus 6 data catalog. Volume 6: Data orbits 4339 through 5155. [from May through June 1976

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Satellite operations from launch through 14 July (orbit 425) consisted of engineering evaluation of all spacecraft systems. As a result of that effort, data reception, accountability and processing were intermittent during that period. During orbit 4905 (12 June), Nimbus 6 successfully completed one year operations. A summary of the documentation for each Nimbus 6 Data Catalog volume is presented. The pitch of the Nimbus 6 satellite has been made to alternate between +2.0 degrees, +0.6 degrees, and 0.0 degrees since launch. A positive pitch angle of 0.6 degrees moves the nadir-looking position 11.5 kilometers ahead of the subsatellite point. A positive pitch angle of 2.0 degrees moves the nadir-looking position 38.3 kilometers ahead of the subsatellite point. At these pitch angles, a scanner-type instrument no longer scans the earth along a great circle arc through the subpoint, but scans along the small circle formed by the intersection of the scan plane with the earth. Since the plane of the small circle is tilted with respect to the nominal scan plane, points on the arc are displaced farther from the great circle as the scan angle increases. As noted above, a pitch angle of 0.6 degrees causes a displacement of 11.5 kilometers at nadir, but when the scanner turns 45 degrees away from nadir the displacement increases slightly to 12.8 kilometers. Similarly, for a 2.0 degree pitch the displacement is 38.3 kilometers at nadir and increases to 42.6 kilometers at a 45 degree scan angle. Thus, although the instrument records in lines normal to the orbit plane (in the absence of yaw) the perpendicular displacement from the perfect-attitude scan line is not uniform across the scan line.

  9. Three-dimensional collimation of in-plane-propagating light using silicon micromachined mirror

    NASA Astrophysics Data System (ADS)

    Sabry, Yasser M.; Khalil, Diaa; Saadany, Bassam; Bourouina, Tarik

    2014-03-01

    We demonstrate light collimation of single-mode optical fibers using deeply-etched three-dimensional curved micromirror on silicon chip. The three-dimensional curvature of the mirror is controlled by a process combining deep reactive ion etching and isotropic etching of silicon. The produced surface is astigmatic with out-of-plane radius of curvature that is about one half the in-plane radius of curvature. Having a 300-μm in-plane radius and incident beam inplane inclined with an angle of 45 degrees with respect to the principal axis, the reflected beam is maintained stigmatic with about 4.25 times reduction in the beam expansion angle in free space and about 12-dB reduction in propagation losses, when received by a limited-aperture detector.

  10. Root surface removal and resultant surface texture with diamond-coated ultrasonic inserts: an in vitro and SEM study.

    PubMed

    Vastardis, Sotirios; Yukna, Raymond A; Rice, David A; Mercante, Don

    2005-05-01

    A new diamond-coated ultrasonic insert has been developed for scaling and root planing, and it was evaluated in vitro for the amount of root surface removed and the roughness of the residual root surface as a result of instrumentation. 48 extracted single-rooted human teeth were ground flat on one root surface and mounted (flat side up) in PVC rings of standard height and diameter with improved dental stone. Each tooth surface was treated with either a plain ultrasonic insert (PI), an ultrasonic insert with a fine grit diamond coating (DI) or sharp Gracey curettes (HI). The mounted teeth were attached to a stepper motor which drove the teeth in a horizontal, reciprocal motion at a constant rate. The thickness from the flattened bottom of the ring to the flattened tooth surface was measured before and after 10, 20, and 30 instrumentation strokes for each root surface with each of the experimental instruments. A number of treated teeth were randomly selected for examination with SEM and a profilometer. Statistical analysis (analysis of co-variance) was performed to compare the amounts of tooth structure removed among the 3 instruments and t-test was used to compare the roughness of the treated root surfaces. The mean depth of root structure removed was PI 10.7 microm, HI 15.0 microm, and DI 46.2 microm after 10 strokes; and PI 21.6 microm, HI 33.2 and DI 142.0 microm after 30 strokes, respectively. On average, 0.9 microm, 1.3 microm, and 4.7 microm of root surface was removed with each stroke of PI, HI and DI, respectively. PI and HI were not different from each other for all the stroke cycles, while DI was significantly different from PI and HI for all the stroke cycles (p<0.0001). Analysis with the profilometer showed that the smoothest surface was produced by the PI followed by the HI. The DI produced a surface that was significantly rougher than the surface produced by the PI or HI. These results suggest that diamond-coated ultrasonic instruments will effectively plane roots, and that caution should be used during periodontal root planing procedures. Additionally, the diamond-coated instruments will produce a rougher surface than the plain inserts or the hand curettes.

  11. Wing-wake interaction destabilizes hover equilibrium of a flapping insect-scale wing.

    PubMed

    Bluman, James; Kang, Chang-Kwon

    2017-06-15

    Wing-wake interaction is a characteristic nonlinear flow feature that can enhance unsteady lift in flapping flight. However, the effects of wing-wake interaction on the flight dynamics of hover are inadequately understood. We use a well-validated 2D Navier-Stokes equation solver and a quasi-steady model to investigate the role of wing-wake interaction on the hover stability of a fruit fly scale flapping flyer. The Navier-Stokes equations capture wing-wake interaction, whereas the quasi-steady models do not. Both aerodynamic models are tightly coupled to a flight dynamic model, which includes the effects of wing mass. The flapping amplitude, stroke plane angle, and flapping offset angle are adjusted in free flight for various wing rotations to achieve hover equilibrium. We present stability results for 152 simulations which consider different kinematics involving the pitch amplitude and pitch axis as well as the duration and timing of pitch rotation. The stability of all studied motions was qualitatively similar, with an unstable oscillatory mode present in each case. Wing-wake interaction has a destabilizing effect on the longitudinal stability, which cannot be predicted by a quasi-steady model. Wing-wake interaction increases the tendency of the flapping flyer to pitch up in the presence of a horizontal velocity perturbation, which further destabilizes the unstable oscillatory mode of hovering flight dynamics.

  12. Angle amplifying optics using plane and ellipsoidal reflectors

    DOEpatents

    Glass, Alexander J.

    1977-01-01

    An optical system for providing a wide angle input beam into ellipsoidal laser fusion target illumination systems. The optical system comprises one or more pairs of centrally apertured plane and ellipsoidal mirrors disposed to accept the light input from a conventional lens of modest focal length and thickness, to increase the angular divergence thereof to a value equivalent to that of fast lenses, and to direct the light into the ellipsoidal target illumination system.

  13. Design of a High Speed Planing Hull with a Cambered Step and Surface Piercing Hydrofoils

    DTIC Science & Technology

    2014-06-01

    Impact Acceleration (Hoggard and Jones) - 1/10 highest eta_110_CG = 7.0*( H13 /Bpx)*(1+Tau/2...hulls with a higher deadrise angle perform better, with improved ride quality as the impact of wave is reduced. However, there is a disadvantage...the previous studies of Blount, Codega and Savitsky, a planing hull’s running trim angle and associated lift coefficient has a large impact on dynamic

  14. How gender and boat-side affect shape characteristics of force-angle profiles in single sculling: Insights from functional data analysis.

    PubMed

    Warmenhoven, John; Cobley, Stephen; Draper, Conny; Harrison, Andrew; Bargary, Norma; Smith, Richard

    2018-05-01

    To examine whether gender or side of the boat influenced shape characteristics of the force-angle profile in on-water single sculling. Cross-sectional study design. Bivariate functional principal components analysis (bfPCA) was applied to force-angle data to identify the main modes of variance in curves of forty highly skilled male and female rowers (national and international level), rowing at 32 strokes per minute in a single scull boat. Separate discriminant function analyses for each side of the boat showed strong classification of rowers for gender. Force application close to (or closely around) the perpendicular oar position was demonstrated to be different between genders. A mixed ANOVA exploring gender, boat side and their interaction revealed that bow and stroke side forces were also statistically different from each other independently of gender. A main effect, independent of side of the boat, was also present for gender and no interaction was found between gender and boat side. Bow side forces seemingly acted as a driver of power and peak force production, while stroke side forces may have acted as a mediator of propulsive forces with an additional potential role in steering due to known asymmetrical offsets in boat rigging. Results demonstrate that propulsive force differences according to gender and boat-side are evident and must be acknowledged and accounted for before force-angle graphs are explored relative to performance measures. Copyright © 2017. Published by Elsevier Ltd.

  15. A new spherical model for computing the radiation field available for photolysis and heating at twilight

    NASA Technical Reports Server (NTRS)

    Dahlback, Arne; Stamnes, Knut

    1991-01-01

    Accurate computation of atmospheric photodissociation and heating rates is needed in photochemical models. These quantities are proportional to the mean intensity of the solar radiation penetrating to various levels in the atmosphere. For large solar zenith angles a solution of the radiative transfer equation valid for a spherical atmosphere is required in order to obtain accurate values of the mean intensity. Such a solution based on a perturbation technique combined with the discrete ordinate method is presented. Mean intensity calculations are carried out for various solar zenith angles. These results are compared with calculations from a plane parallel radiative transfer model in order to assess the importance of using correct geometry around sunrise and sunset. This comparison shows, in agreement with previous investigations, that for solar zenith angles less than 90 deg adequate solutions are obtained for plane parallel geometry as long as spherical geometry is used to compute the direct beam attenuation; but for solar zenith angles greater than 90 deg this pseudospherical plane parallel approximation overstimates the mean intensity.

  16. Crystal structure of 3-(2,5-di-meth-oxy-phen-yl)propionic acid.

    PubMed

    Bugenhagen, Bernhard; Al Jasem, Yosef; AlAzani, Mariam; Thiemann, Thies

    2015-05-01

    In the crystal of the title compound, C11H14O4, the aromatic ring is almost coplanar with the 2-position meth-oxy group with which it subtends a dihedral of 0.54 (2)°, while the 5-position meth-oxy group makes a corresponding dihedral angle of just 5.30 (2)°. The angle between the mean planes of the aromatic ring and the propionic acid group is 78.56 (2)°. The fully extended propionic side chain is in a trans configuration with a C-C-C-C torsion angle of -172.25 (7)°. In the crystal, hydrogen bonding is limited to dimer formation via R 2 (2)(8) rings. The hydrogen-bonded dimers are stacked along the b axis. The average planes of the two benzene rings in a dimer are parallel to each other, but at an offset of 4.31 (2) Å. Within neighbouring dimers along the [101] direction, the average mol-ecular benzene planes are almost perpendicular to each other, with a dihedral angle of 85.33 (2)°.

  17. Scaling of swim speed and stroke frequency in geometrically similar penguins: they swim optimally to minimize cost of transport

    PubMed Central

    Sato, Katsufumi; Shiomi, Kozue; Watanabe, Yuuki; Watanuki, Yutaka; Takahashi, Akinori; Ponganis, Paul J.

    2010-01-01

    It has been predicted that geometrically similar animals would swim at the same speed with stroke frequency scaling with mass−1/3. In the present study, morphological and behavioural data obtained from free-ranging penguins (seven species) were compared. Morphological measurements support the geometrical similarity. However, cruising speeds of 1.8–2.3 m s−1 were significantly related to mass0.08 and stroke frequencies were proportional to mass−0.29. These scaling relationships do not agree with the previous predictions for geometrically similar animals. We propose a theoretical model, considering metabolic cost, work against mechanical forces (drag and buoyancy), pitch angle and dive depth. This new model predicts that: (i) the optimal swim speed, which minimizes the energy cost of transport, is proportional to (basal metabolic rate/drag)1/3 independent of buoyancy, pitch angle and dive depth; (ii) the optimal speed is related to mass0.05; and (iii) stroke frequency is proportional to mass−0.28. The observed scaling relationships of penguins support these predictions, which suggest that breath-hold divers swam optimally to minimize the cost of transport, including mechanical and metabolic energy during dive. PMID:19906666

  18. The reliability of humerothoracic angles during arm elevation depends on the representation of rotations.

    PubMed

    López-Pascual, Juan; Cáceres, Magda Liliana; De Rosario, Helios; Page, Álvaro

    2016-02-08

    The reliability of joint rotation measurements is an issue of major interest, especially in clinical applications. The effect of instrumental errors and soft tissue artifacts on the variability of human motion measures is well known, but the influence of the representation of joint motion has not yet been studied. The aim of the study was to compare the within-subject reliability of three rotation formalisms for the calculation of the shoulder elevation joint angles. Five repetitions of humeral elevation in the scapular plane of 27 healthy subjects were recorded using a stereophotogrammetry system. The humerothoracic joint angles were calculated using the YX'Y" and XZ'Y" Euler angle sequences and the attitude vector. A within-subject repeatability study was performed for the three representations. ICC, SEM and CV were the indices used to estimate the error in the calculation of the angle amplitudes and the angular waveforms with each method. Excellent results were obtained in all representations for the main angle (elevation), but there were remarkable differences for axial rotation and plane of elevation. The YX'Y" sequence generally had the poorest reliability in the secondary angles. The XZ'Y' sequence proved to be the most reliable representation of axial rotation, whereas the attitude vector had the highest reliability in the plane of elevation. These results highlight the importance of selecting the method used to describe the joint motion when within-subjects reliability is an important issue of the experiment. This may be of particular importance when the secondary angles of motions are being studied. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. The evaluation of the angles of Eustachian tubes in the patients with chronic otitis media on the temporal computerized tomography.

    PubMed

    Aksoy, S; Sayin, I; Yazici, Z M; Kayhan, F T; Karahasanoglu, A; Hocaoglu, E; Inci, E

    2016-01-01

    Chronic otitis media (COM), affecting all over the world and in a wide range of age groups in Turkey, is an important cause of ear discharge and hearing loss. The main clinical manifestations are tympanic membrane perforation, ear, nose and throat problems. On the tympanic membrane perforation becomes persistent and cholesteatoma development, there are a lot of opinions today. Especially in the pathology associated with otitis media with effusion eustachian tube, it is known that COM and cholesteatoma develop. In our study, we interpreted 210 patients' temporal computed tomography (CT). Seventy of these 210 patients had otitis media with cholesteatoma, 70 patients had only otitis media without cholesteatoma, and 70 patients had no otitis media. The eustachian tubes were evaluated using temporal CT multiplanar reconstruction method. Angles with the horizontal plane of the eustachian tube and Reid and tubotympanic angles were measured. The angles between eustachian tube and horizontally oriented Reid plane of the patients with cholesteatoma were found to be significantly lower than the patients with otitis media without cholesteatoma and the patients with no history of otitis media. For the tubotympanic angle, no statistically significant differences were observed between the groups. These results suggest that the decrease in the angle with the horizontal plane of Reid in the eustachian tube in adults may play a significant role in the etiology of cholesteatoma.

  20. Multi-objective optimization and design for free piston Stirling engines based on the dimensionless power

    NASA Astrophysics Data System (ADS)

    Mou, Jian; Hong, Guotong

    2017-02-01

    In this paper, the dimensionless power is used to optimize the free piston Stirling engines (FPSE). The dimensionless power is defined as a ratio of the heat power loss and the output work. The heat power losses include the losses of expansion space, heater, regenerator, cooler and the compression space and every kind of the heat loss calculated by empirical formula. The output work is calculated by the adiabatic model. The results show that 82.66% of the losses come from the expansion space and 54.59% heat losses of expansion space come from the shuttle loss. At different pressure the optimum bore-stroke ratio, heat source temperature, phase angle and the frequency have different values, the optimum phase angles increase with the increase of pressure, but optimum frequencies drop with the increase of pressure. However, no matter what the heat source temperature, initial pressure and frequency are, the optimum ratios of piston stroke and displacer stroke all about 0.8. The three-dimensional diagram is used to analyse Stirling engine. From the three-dimensional diagram the optimum phase angle, frequency and heat source temperature can be acquired at the same time. This study offers some guides for the design and optimization of FPSEs.

  1. A Study of a Mini-Drift GEM Tracking Detector

    DOE PAGES

    Azmoun, B.; DiRuzza, B.; Franz, A.; ...

    2016-06-22

    In this paper, a GEM tracking detector with an extended drift region has been studied as part of an effort to develop new tracking detectors for future experiments at RHIC and for the Electron Ion Collider that is being planned for BNL or JLAB. The detector consists of a triple GEM stack with a 1.6 cm drift region that was operated in a mini TPC type configuration. Both the position and arrival time of the charge deposited in the drift region were measured on the readout plane which allowed the reconstruction of a short vector for the track traversing themore » chamber. The resulting position and angle information from the vector could then be used to improve the position resolution of the detector for larger angle tracks, which deteriorates rapidly with increasing angle for conventional GEM tracking detectors using only charge centroid information. Two types of readout planes were studied. One was a COMPASS style readout plane with 400 μm pitch XY strips and the other consisted of 2 × 10 mm 2 chevron pads. The detector was studied in test beams at Fermilab and CERN, along with additional measurements in the lab, in order to determine its position and angular resolution for incident track angles up to 45 degrees. Several algorithms were studied for reconstructing the vector using the position and timing information in order to optimize the position and angular resolution of the detector for the different readout planes. Finally, applications for large angle tracking detectors at RHIC and EIC are also discussed.« less

  2. A Study of a Mini-Drift GEM Tracking Detector

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

    Azmoun, B.; DiRuzza, B.; Franz, A.

    In this paper, a GEM tracking detector with an extended drift region has been studied as part of an effort to develop new tracking detectors for future experiments at RHIC and for the Electron Ion Collider that is being planned for BNL or JLAB. The detector consists of a triple GEM stack with a 1.6 cm drift region that was operated in a mini TPC type configuration. Both the position and arrival time of the charge deposited in the drift region were measured on the readout plane which allowed the reconstruction of a short vector for the track traversing themore » chamber. The resulting position and angle information from the vector could then be used to improve the position resolution of the detector for larger angle tracks, which deteriorates rapidly with increasing angle for conventional GEM tracking detectors using only charge centroid information. Two types of readout planes were studied. One was a COMPASS style readout plane with 400 μm pitch XY strips and the other consisted of 2 × 10 mm 2 chevron pads. The detector was studied in test beams at Fermilab and CERN, along with additional measurements in the lab, in order to determine its position and angular resolution for incident track angles up to 45 degrees. Several algorithms were studied for reconstructing the vector using the position and timing information in order to optimize the position and angular resolution of the detector for the different readout planes. Finally, applications for large angle tracking detectors at RHIC and EIC are also discussed.« less

  3. Wettability control of droplet deposition and detachment.

    PubMed

    Baret, Jean-Christophe; Brinkmann, Martin

    2006-04-14

    The conditions for droplet deposition on plane substrates are studied using electrowetting to continuously modulate the surface wettability. Droplets of controlled volume attached to the tip of a pipette are brought into contact with the surface. During retraction of the pipette the droplets are deposited or detach completely depending on volume and contact angle. The experimental limit of deposition in the contact angle or volume plane is in good agreement with analytical and numerical predictions obtained within the capillary model.

  4. Frontal plane landing mechanics in high-arched compared with low-arched female athletes.

    PubMed

    Powell, Douglas W; Hanson, Nicholas J; Long, Benjamin; Williams, D S Blaise

    2012-09-01

    To examine ground reaction forces (GRFs); frontal plane hip, knee, and ankle joint angles; and moments in high-arched (HA) and low-arched (LA) athletes during landing. Experimental study. Controlled research laboratory. Twenty healthy female recreational athletes (10 HA and 10 LA). Athletes performed 5 barefoot drop landings from a height of 30 cm. Frontal plane ankle, knee, and hip joint angles (in degrees) at initial contact, peak vertical GRF, and peak knee flexion; peak ankle, knee, and hip joint moments in the frontal plane. Vertical GRF profiles were similar between HA and LA athletes (P = 0.78). The HA athletes exhibited significantly smaller peak ankle inversion angles than the LA athletes (P = 0.01) at initial contact. At peak vertical GRF, HA athletes had significantly greater peak knee (P = 0.01) and hip abduction angles than LA athletes (P = 0.02). There were no significant differences between HA and LA athletes in peak joint moments (hip: P = 0.68; knee: P = 0.71; ankle: P = 0.15). These findings demonstrate that foot type is associated with altered landing mechanics, which may underlie lower extremity injuries. The ankle-driven strategy previously reported in female athletes suggests that foot function may have a greater relationship with lower extremity injury than that in male athletes. Future research should address the interaction of foot type and gender during landing tasks.

  5. Dynamics of Folds in the Plane

    ERIC Educational Resources Information Center

    Krylov, Nikolai A.; Rogers, Edwin L.

    2011-01-01

    Take a strip of paper and fold a crease intersecting the long edges, creating two angles. Choose one edge and consider the angle with the crease. Fold the opposite edge along the crease, creating a new crease that bisects the angle. Fold again, this time using the newly created crease and the initial edge, creating a new angle along the chosen…

  6. Possibility of Atherosclerosis in an Arterial Bifurcation Model

    PubMed Central

    Arjmandi-Tash, Omid; Razavi, Seyed Esmail; Zanbouri, Ramin

    2011-01-01

    Introduction Arterial bifurcations are susceptible locations for formation of atherosclerotic plaques. In the present study, steady blood flow is investigated in a bifurcation model with a non-planar branch. Methods The influence of different bifurcation angles and non-planar branch is demonstrated on wall shear stress (WSS) distribution using three-dimensional Navier–Stokes equations. Results The WSS values are low in two locations at the top and bottom walls of the mother vessels just before the bifurcation, especially for higher bifurcation angles. These regions approach the apex of bifurcation with decreasing the bifurcation angle. The WSS magnitudes approach near to zero at the outer side of bifurcation plane and these locations are separation-prone. By increasing the bifurcation angle, the minimum WSS decreases at the outer side of bifurcation plane but low WSS region squeezes. WSS peaks exist on the inner side of bifurcation plane near the entry section of daughter vessels and these initial peaks drop as bifurcation angle is increased. Conclusion It is concluded that the non-planarity of the daughter vessel lowers the minimum WSS at the outer side of bifurcation and increases the maximum WSS at the inner side. So it seems that the formation of atherosclerotic plaques at bifurcation region in direction of non-planar daughter vessel is more risky. PMID:23678432

  7. Mathematical modeling of the crack growth in linear elastic isotropic materials by conventional fracture mechanics approaches and by molecular dynamics method: crack propagation direction angle under mixed mode loading

    NASA Astrophysics Data System (ADS)

    Stepanova, Larisa; Bronnikov, Sergej

    2018-03-01

    The crack growth directional angles in the isotropic linear elastic plane with the central crack under mixed-mode loading conditions for the full range of the mixity parameter are found. Two fracture criteria of traditional linear fracture mechanics (maximum tangential stress and minimum strain energy density criteria) are used. Atomistic simulations of the central crack growth process in an infinite plane medium under mixed-mode loading using Large-scale Molecular Massively Parallel Simulator (LAMMPS), a classical molecular dynamics code, are performed. The inter-atomic potential used in this investigation is Embedded Atom Method (EAM) potential. The plane specimens with initial central crack were subjected to Mixed-Mode loadings. The simulation cell contains 400000 atoms. The crack propagation direction angles under different values of the mixity parameter in a wide range of values from pure tensile loading to pure shear loading in a wide diapason of temperatures (from 0.1 К to 800 К) are obtained and analyzed. It is shown that the crack propagation direction angles obtained by molecular dynamics method coincide with the crack propagation direction angles given by the multi-parameter fracture criteria based on the strain energy density and the multi-parameter description of the crack-tip fields.

  8. Altered astronaut lower limb and mass center kinematics in downward jumping following space flight

    NASA Technical Reports Server (NTRS)

    Newman, D. J.; Jackson, D. K.; Bloomberg, J. J.

    1997-01-01

    Astronauts exposed to the microgravity conditions encountered during space flight exhibit postural and gait instabilities upon return to earth that could impair critical postflight performance. The aim of the present study was to determine the effects of microgravity exposure on astronauts' performance of two-footed jump landings. Nine astronauts from several Space Shuttle missions were tested both preflight and postflight with a series of voluntary, two-footed downward hops from a 30-cm-high step. A video-based, three-dimensional motion-analysis system permitted calculation of body segment positions and joint angular displacements. Phase-plane plots of knee, hip, and ankle angular velocities compared with the corresponding joint angles were used to describe the lower limb kinematics during jump landings. The position of the whole-body center of mass (COM) was also estimated in the sagittal plane using an eight-segment body model. Four of nine subjects exhibited expanded phase-plane portraits postflight, with significant increases in peak joint flexion angles and flexion rates following space flight. In contrast, two subjects showed significant contractions of their phase-plane portraits postflight and three subjects showed insignificant overall changes after space flight. Analysis of the vertical COM motion generally supported the joint angle results. Subjects with expanded joint angle phase-plane portraits postflight exhibited larger downward deviations of the COM and longer times from impact to peak deflection, as well as lower upward recovery velocities. Subjects with postflight joint angle phase-plane contraction demonstrated opposite effects in the COM motion. The joint kinematics results indicated the existence of two contrasting response modes due to microgravity exposure. Most subjects exhibited "compliant" impact absorption postflight, consistent with decreased limb stiffness and damping, and a reduction in the bandwidth of the postural control system. Fewer subjects showed "stiff" behavior after space flight, where contractions in the phase-plane portraits pointed to an increase in control bandwidth. The changes appeared to result from adaptive modifications in the control of lower limb impedance. A simple 2nd-order model of the vertical COM motion indicated that changes in the effective vertical stiffness of the legs can predict key features of the postflight performance. Compliant responses may reflect inflight adaptation due to altered demands on the postural control system in microgravity, while stiff behavior may result from overcompensation postflight for the presumed reduction in limb stiffness inflight.

  9. Methods and Devices for Space Optical Communications Using Laser Beams

    NASA Technical Reports Server (NTRS)

    Goorjian, Peter M. (Inventor)

    2018-01-01

    Light is used to communicate between objects separated by a large distance. Light beams are received in a telescopic lens assembly positioned in front of a cat's-eye lens. The light can thereby be received at various angles to be output by the cat's-eye lens to a focal plane of the cat's-eye lens, the position of the light beams upon the focal plane corresponding to the angle of the beam received. Lasers and photodetectors are distributed along this focal plane. A processor receives signals from the photodetectors, and selectively signal lasers positioned proximate the photodetectors detecting light, in order to transmit light encoding data through the cat's-eye lens and also through a telescopic lens back in the direction of the received light beams, which direction corresponds to a location upon the focal plane of the transmitting lasers.

  10. Analysis of an infinite array of rectangular microstrip patches with idealized probe feeds

    NASA Technical Reports Server (NTRS)

    Pozar, D. M.; Schaubert, D. H.

    1984-01-01

    A solution is presented to the problem of an infinite array of microstrip patches fed by idealized current probes. The input reflection coefficient is calculated versus scan angle in an arbitrary scan plane, and the effects of substrate parameters and grid spacing are considered. It is pointed out that even when a Galerkin method is used the impedance matrix is not symmetric due to phasing through a unit cell, as required for scanning. The mechanism by which scan blindness can occur is discussed. Measurement results are presented for the reflection coefficient magnitude variation with angle for E-plane, H-plane, and D-plane scans, for various substrate parameters. Measured results from waveguide simulators are also presented, and the scan blindness phenomenon is observed and discussed in terms of forced surface waves and a modified grating lobe diagram.

  11. Electric-regulated enhanced in-plane uniaxial anisotropy in FeGa/PMN-PT composite using oblique pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Zhang, Yi; Huang, Chaojuan; Turghun, Mutellip; Duan, Zhihua; Wang, Feifei; Shi, Wangzhou

    2018-04-01

    The FeGa film with in-plane uniaxial magnetic anisotropy was fabricated onto different oriented single-crystal lead magnesium niobate-lead titanate using oblique pulsed laser deposition. An enhanced in-plane uniaxial magnetic anisotropy field of FeGa film can be adjusted from 18 Oe to 275 Oe by tuning the oblique angle and polarizing voltage. The competitive relationship of shape anisotropy and strain anisotropy has been discussed, which was induced by oblique angle and polarizing voltage, respectively. The (100)-oriented and (110)-oriented PMN-PT show completely different characters on voltage-dependent magnetic properties, which could be attributed to various anisotropy directions depended on different strain directions.

  12. Chevron osteotomy in patients with scheduled osteotomy of the medial malleolus.

    PubMed

    Gül, Murat; Yavuz, Umut; Çetinkaya, Engin; Aykut, Ümit Selçuk; Özkul, Barış; Kabukçuoğlu, Yavuz Selim

    2015-01-01

    The aim of the present study was to evaluate intermediate-term outcomes of Chevron osteotomy for treatment of osteochondral lesions of the talus with mosaicplasty and to assess its effect on surgery and whether it reduces complications that might occur intraoperatively. The present study included a total of 42 patients (31 men, 11 women) who underwent Chevron osteotomy of the medial malleolus and who had been followed for more than 2 years. Mean age of the patients was 34 years (range: 18-54 years). Preoperatively, size of the lesions was measured in millimeters in the coronal and sagittal planes using magnetic resonance imaging (MRI). The angle between the osteotomy with the long axis of the tibia was measured on the coronal plane, the angle between the arms and the angle for the screws to be directed to the osteotomy line were measured on the sagittal plane on the postoperative images. Nonunion, malunion, and complications from the screws were evaluated from X-ray images taken at the final follow-up. Mean duration for follow-up was 31.4 years (range: 24-46). On the X-ray images taken at the final follow-up, no distraction, migration of the distal part, or rotation was observed. Only 1 patient experienced radiological non-union. Mean duration to union was 5.8 weeks (range: 4-14 weeks). Screws of 8 patients were removed at an average of 7.4 months (range: 5-11 months). The angle between the osteotomy line and long axis of the tibia was 29.0°±6.5°, the angel between the osteotomy arms on the sagittal plane was 74.7°±8.3°, and the direction angle of the screws on the coronal plane was 85.7°±5.9°. Chevron osteotomy is an assistive surgical method used for treatment of osteochondral lesions located in the medial talar joint surface (TOL) which provides fast anatomical healing because it allows efficient fixation due to its geometry.

  13. EMG-based pattern recognition approach in post stroke robot-aided rehabilitation: a feasibility study

    PubMed Central

    2013-01-01

    Background Several studies investigating the use of electromyographic (EMG) signals in robot-based stroke neuro-rehabilitation to enhance functional recovery. Here we explored whether a classical EMG-based patterns recognition approach could be employed to predict patients’ intentions while attempting to generate goal-directed movements in the horizontal plane. Methods Nine right-handed healthy subjects and seven right-handed stroke survivors performed reaching movements in the horizontal plane. EMG signals were recorded and used to identify the intended motion direction of the subjects. To this aim, a standard pattern recognition algorithm (i.e., Support Vector Machine, SVM) was used. Different tests were carried out to understand the role of the inter- and intra-subjects’ variability in affecting classifier accuracy. Abnormal muscular spatial patterns generating misclassification were evaluated by means of an assessment index calculated from the results achieved with the PCA, i.e., the so-called Coefficient of Expressiveness (CoE). Results Processing the EMG signals of the healthy subjects, in most of the cases we were able to build a static functional map of the EMG activation patterns for point-to-point reaching movements on the horizontal plane. On the contrary, when processing the EMG signals of the pathological subjects a good classification was not possible. In particular, patients’ aimed movement direction was not predictable with sufficient accuracy either when using the general map extracted from data of normal subjects and when tuning the classifier on the EMG signals recorded from each patient. Conclusions The experimental findings herein reported show that the use of EMG patterns recognition approach might not be practical to decode movement intention in subjects with neurological injury such as stroke. Rather than estimate motion from EMGs, future scenarios should encourage the utilization of these signals to detect and interpret the normal and abnormal muscle patterns and provide feedback on their correct recruitment. PMID:23855907

  14. (1R,4R,7S)-1,7-Dimethyl-7-(phenyl-sulfonyl-meth-yl)spiro-[bicyclo-[2.2.1]heptane-2,2'-1,3-dioxolane].

    PubMed

    Wang, Ya-Wen; Peng, Yu

    2007-12-06

    In the title compound, C(18)H(24)O(4)S, the chiral bicyclo-[2.2.1]heptane group is not symmetrical due to the influence of the substituents. The angle between the three-atom bridge plane and the four-atom planes of the boat-shaped six-membered ring are 55.07 (19) and 56.24 (19)°. The bridgehead angle is 92.75 (17)°.

  15. Bistatic 3D Electromagnetic Scattering From a Right-Angle Dihedral at Arbitrary Orientation and Position

    DTIC Science & Technology

    2011-03-24

    compared to shooting and bouncing rays (SBR) and method of moments (MoM) predictions, as well as measured data for applicable cases. The model in this...prediction codes based on Shooting and Bouncing Rays (SBR) or Method of Moments (MoM) can be used to obtain accurate bistatic scatter- ing solutions for a...in-plane RCS pattern for dihedral. (a) For monostatic in-plane scattering, rays entering a right-angle dihedral are reflected back in the direction

  16. Magnetic quantum oscillations in doped antiferromagnets

    NASA Astrophysics Data System (ADS)

    Kabanov, V. V.

    2017-10-01

    Energy spectrum of electrons (holes) doped into two-dimensional (2D) antiferromagnetic (AF) semiconductors is quantized in an external magnetic field of arbitrary direction. A peculiar dependence of de Haas-van Alphen (dHvA) magneto-oscillation amplitudes on the azimuthal in-plane angle from the magnetization direction and on the polar angle from the out-of-plane direction is found. The angular dependence of the amplitude is different if the measurements are performed in the field above and below of the spin-flop field.

  17. 1-Allyl-3-chloro-5-nitro-1H-indazole

    PubMed Central

    Chicha, Hakima; Rakib, El Mostapha; Spinelli, Domenico; Saadi, Mohamed; El Ammari, Lahcen

    2013-01-01

    In the title compound, C10H8ClN3O2, the indazole ring system makes a dihedral angle of 7.9 (3)° with the plane through the nitro group. The allyl group is rotated out of the plane of the indazole ring system [N—N—C—C torsion angle = 104.28 (19)°]. In the crystal, mol­ecules are linked by C—H⋯O hydrogen bonds, forming zigzag chains propagating along the b-axis direction. PMID:24427047

  18. 1-Allyl-3-chloro-5-nitro-1H-indazole.

    PubMed

    Chicha, Hakima; Rakib, El Mostapha; Spinelli, Domenico; Saadi, Mohamed; El Ammari, Lahcen

    2013-01-01

    In the title compound, C10H8ClN3O2, the indazole ring system makes a dihedral angle of 7.9 (3)° with the plane through the nitro group. The allyl group is rotated out of the plane of the indazole ring system [N-N-C-C torsion angle = 104.28 (19)°]. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds, forming zigzag chains propagating along the b-axis direction.

  19. One-dimensional pinning behavior in Co-doped BaFe2As2 thin films

    NASA Astrophysics Data System (ADS)

    Mishev, V.; Seeböck, W.; Eisterer, M.; Iida, K.; Kurth, F.; Hänisch, J.; Reich, E.; Holzapfel, B.

    2013-12-01

    Angle-resolved transport measurements revealed that planar defects dominate flux pinning in the investigated Co-doped BaFe2As2 thin film. For any given field and temperature, the critical current depends only on the angle between the crystallographic c-axis and the applied magnetic field but not on the angle between the current and the field. The critical current is therefore limited only by the in-plane component of the Lorentz force but independent of the out-of-plane component, which is entirely balanced by the pinning force exerted by the planar defects. This one-dimensional pinning behavior shows similarities and differences to intrinsic pinning in layered superconductors.

  20. Approximate heating analysis for the windward-symmetry plane of Shuttle-like bodies at large angle of attack

    NASA Technical Reports Server (NTRS)

    Zoby, E. V.

    1981-01-01

    An engineering method has been developed for computing the windward-symmetry plane convective heat-transfer rates on Shuttle-like vehicles at large angles of attack. The engineering code includes an approximate inviscid flowfield technique, laminar and turbulent heating-rate expressions, an approximation to account for the variable-entropy effects on the surface heating and the concept of an equivalent axisymmetric body to model the windward-ray flowfields of Shuttle-like vehicles at angles of attack from 25 to 45 degrees. The engineering method is validated by comparing computed heating results with corresponding experimental data measured on Shuttle and advanced transportation models over a wide range of flow conditions and angles of attack from 25 to 40 degrees and also with results of existing prediction techniques. The comparisons are in good agreement.

  1. The effect of tibiotalar alignment on coronal plane mechanics following total ankle replacement.

    PubMed

    Grier, A Jordan; Schmitt, Abigail C; Adams, Samuel B; Queen, Robin M

    2016-07-01

    Gait mechanics following total ankle replacement (TAR) have reported improved ankle motion following surgery. However, no studies have addressed the impact of preoperative radiographic tibiotalar alignment on post-TAR gait mechanics. We therefore investigated whether preoperative tibiotalar alignment (varus, valgus, or neutral) resulted in significantly different coronal plane mechanics or ground reaction forces post-TAR. We conducted a non-randomized study of 93 consecutive end-stage ankle arthritis patients. Standard weight-bearing radiographs were obtained preoperatively to categorize patients as having neutral (±4°), varus (≥5° of varus), or valgus (≥5° of valgus) coronal plane tibiotalar alignment. All patients underwent a standard walking assessment including three-dimensional lower extremity kinetics and kinematics preoperatively, 12 and 24 months postoperatively. A significant group by time interaction was observed for the propulsive vertical ground reaction force (vGRF), coronal plane hip range of motion (ROM) and the peak hip abduction moment. The valgus group demonstrated an increase in the peak knee adduction angle and knee adduction angle at heel strike when compared to the other groups. Coronal plane ankle ROM, knee and hip angles at heel strike, and the peak hip angle exhibited significant increases across time. Peak ankle inversion moment, peak knee abduction moment and the weight acceptance vGRF also exhibited significant increases across time. Neutral ankle alignment was achieved for all patients by 2 years following TAR. Restoration of neutral ankle alignment at the time of TAR in patients with preoperative varus or valgus tibiotalar alignment resulted in biomechanics similar to those of patients with neutral preoperative tibiotalar alignment by 24-month follow-up. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Correction Capability in the 3 Anatomic Planes of Different Pedicle Screw Designs in Scoliosis Instrumentation.

    PubMed

    Wang, Xiaoyu; Aubin, Carl-Eric; Coleman, John; Rawlinson, Jeremy

    2017-05-01

    Computer simulations to compare the correction capabilities of different pedicle screws in adolescent idiopathic scoliosis (AIS) instrumentations. To compare the correction and resulting bone-screw forces associated with different pedicle screws in scoliosis instrumentations. Pedicle screw fixation is widely used in surgical instrumentation for spinal deformity treatment. Screw design, correction philosophies, and surgical techniques are constantly evolving to achieve better control of the vertebrae and correction of the spinal deformity. Yet, there remains a lack of biomechanical studies that quantify the effects and advantages of different screw designs in terms of correction kinematics. The correction capabilities of fixed-angle, multiaxial, uniaxial, and saddle axial screws were kinematically analyzed, simulated, and compared. These simulations were based on the screw patterns and correction techniques proposed by 2 experienced surgeons for 2 AIS cases. Additional instrumentations were assessed to compare the correction and resulting bone-screw forces associated with each type of screw. The fixed-angle, uniaxial and saddle axial screws had similar kinematic behavior and performed better than multiaxial screws in the coronal and transverse planes (8% and 30% greater simulated corrections, respectively). Uniaxial and multiaxial screws were less effective than fixed-angle and saddle axial screws in transmitting compression/distraction to the anterior spine because of their sagittal plane mobility between the screw head and shank. Only the saddle axial screws allow vertebra angle in the sagittal plane to be independently adjusted. Pedicle screws of different designs performed differently for deformity corrections or for compensating screw placement variations in different anatomic planes. For a given AIS case, screw types should be determined based on the particular instrumentation objectives, the deformity's stiffness and characteristics so as to make the best of the screw designs.

  3. Effects of neural progenitor cells on post-stroke neurological impairment—a detailed and comprehensive analysis of behavioral tests

    PubMed Central

    Doeppner, Thorsten R.; Kaltwasser, Britta; Bähr, Mathias; Hermann, Dirk M.

    2014-01-01

    Systemic transplantation of neural progenitor cells (NPCs) in rodents reduces functional impairment after cerebral ischemia. In light of upcoming stroke trials regarding safety and feasibility of NPC transplantation, experimental studies have to successfully analyze the extent of NPC-induced neurorestoration on the functional level. However, appropriate behavioral tests for analysis of post-stroke motor coordination deficits and cognitive impairment after NPC grafting are not fully established. We therefore exposed male C57BL6 mice to either 45 min (mild) or 90 min (severe) of cerebral ischemia, using the thread occlusion model followed by intravenous injection of PBS or NPCs 6 h post-stroke with an observation period of three months. Post-stroke motor coordination was assessed by means of the rota rod, tight rope, corner turn, inclined plane, grip strength, foot fault, adhesive removal, pole test and balance beam test, whereas cognitive impairment was analyzed using the water maze, the open field and the passive avoidance test. Significant motor coordination differences after both mild and severe cerebral ischemia in favor of NPC-treated mice were observed for each motor coordination test except for the inclined plane and the grip strength test, which only showed significant differences after severe cerebral ischemia. Cognitive impairment after mild cerebral ischemia was successfully assessed using the water maze test, the open field and the passive avoidance test. On the contrary, the water maze test was not suitable in the severe cerebral ischemia paradigm, as it too much depends on motor coordination capabilities of test mice. In terms of both reliability and cost-effectiveness considerations, we thus recommend the corner turn, foot fault, balance beam, and open field test, which do not depend on durations of cerebral ischemia. PMID:25374509

  4. Gap structure of FeSe determined by angle-resolved specific heat measurements in applied rotating magnetic field

    NASA Astrophysics Data System (ADS)

    Sun, Yue; Kittaka, Shunichiro; Nakamura, Shota; Sakakibara, Toshiro; Irie, Koki; Nomoto, Takuya; Machida, Kazushige; Chen, Jingting; Tamegai, Tsuyoshi

    2017-12-01

    Quasiparticle excitations in FeSe were studied by means of specific heat (C ) measurements on a high-quality single crystal under rotating magnetic fields. The field dependence of C shows three-stage behavior with different slopes, indicating the existence of three gaps (Δ1,Δ2, and Δ3). In the low-temperature and low-field region, the azimuthal angle (ϕ ) dependence of C shows a fourfold symmetric oscillation with a sign change. On the other hand, the polar angle (θ ) dependence manifests as an anisotropy-inverted twofold symmetry with unusual shoulder behavior. Combining the angle-resolved results and the theoretical calculation, the smaller gap Δ1 is proved to have two vertical-line nodes or gap minima along the kz direction, and is determined to reside on the electron-type ɛ band. Δ2 is found to be related to the electron-type δ band, and is isotropic in the a b plane but largely anisotropic out of the plane. Δ3 residing on the hole-type α band shows a small out-of-plane anisotropy with a strong Pauli paramagnetic effect.

  5. Object and event recognition for stroke rehabilitation

    NASA Astrophysics Data System (ADS)

    Ghali, Ahmed; Cunningham, Andrew S.; Pridmore, Tony P.

    2003-06-01

    Stroke is a major cause of disability and health care expenditure around the world. Existing stroke rehabilitation methods can be effective but are costly and need to be improved. Even modest improvements in the effectiveness of rehabilitation techniques could produce large benefits in terms of quality of life. The work reported here is part of an ongoing effort to integrate virtual reality and machine vision technologies to produce innovative stroke rehabilitation methods. We describe a combined object recognition and event detection system that provides real time feedback to stroke patients performing everyday kitchen tasks necessary for independent living, e.g. making a cup of coffee. The image plane position of each object, including the patient"s hand, is monitored using histogram-based recognition methods. The relative positions of hand and objects are then reported to a task monitor that compares the patient"s actions against a model of the target task. A prototype system has been constructed and is currently undergoing technical and clinical evaluation.

  6. Epimetheus Above the Rings

    NASA Image and Video Library

    2015-11-09

    Although Epimetheus appears to be lurking above the rings here, it's actually just an illusion resulting from the viewing angle. In reality, Epimetheus and the rings both orbit in Saturn's equatorial plane. Inner moons and rings orbit very near the equatorial plane of each of the four giant planets in our solar system, but more distant moons can have orbits wildly out of the equatorial plane. It has been theorized that the highly inclined orbits of the outer, distant moons are remnants of the random directions from which they approached the planets they orbit. This view looks toward the unilluminated side of the rings from about -0.3 degrees below the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on July 26, 2015. The view was obtained at a distance of approximately 500,000 miles (800,000 kilometers) from Epimetheus and at a Sun-Epimetheus-spacecraft, or phase, angle of 62 degrees. Image scale is 3 miles (5 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA18342

  7. An interplanetary planar magnetic structure oriented at a large (about 80 deg) angle to the Parker spiral

    NASA Technical Reports Server (NTRS)

    Farrugia, M. W.; Dunlop, M. W.; Geurts, F.; Balogh, A.; Southwood, D. J.; Bryant, D. A.; Neugebauer, M.

    1990-01-01

    Magnetic field structures in the solar wind, characterized by a variation of the field vectors within a plane inclined to the ecliptic ('Planar Magnetic Structures', PMSs), were reported recently (Nakagawa et al., 1989). These PMSs have the property that the plane of variation of the field also contains the nominal Parker spiral direction. An observation of a PMS where the direction of the line of intersection of the plane of field variation with the ecliptic plane makes a large (about 80 deg) angle to the Parker spiral direction is presented. Furthermore, the angular variables of the field (1) vary over a restricted range, and (2) are linearly related. The latter property is related to the former. Currently proposed models for the origin of PMS, inasmuch as they require field configurations which retain strict alignment with the Parker spiral direction from formation to observation, are probably incomplete.

  8. Universal Documentation System Handbook. Volume 2: Program Requirements and Operations Requirements Documents

    DTIC Science & Technology

    1979-11-01

    plane. The local horizontal plane is de- lined as a plane normal to the geocentric position vector. Boxes 11J and UJ are the angles measured east...support the program/mission. BOX 1-9 Follow instructions for Pa«« 1010. BOX 10 LOCATION: Enter the areas or locations that are to be staffed with

  9. Effect of Punch Stroke on Deformation During Sheet Forming Through Finite Element

    NASA Astrophysics Data System (ADS)

    Akinlabi, Stephen; Akinlabi, Esther

    2017-08-01

    Forming is one of the traditional methods of making shapes, bends and curvature in metallic components during a fabrication process. Mechanical forming, in particular, employs the use of a punch, which is pressed against the sheet material to be deformed into a die by the application of an external force. This study reports on the finite element analysis of the effects of punch stroke on the resulting sheet deformation, which is directly a function of the structural integrity of the formed components for possible application in the automotive industry. The results show that punch stroke is directly proportional to the resulting bend angle of the formed components. It was further revealed that the developed plastic strain increases as the punch stroke increases.

  10. Study between anb angle and wits appraisal in cone beam computed tomography (cbct)

    PubMed Central

    Cibrián, Rosa; Gandia, Jose L.; Paredes, Vanessa

    2013-01-01

    Objectives: To analyse the ANB and Wits values and to study correlations between those two measurements and other measurements in diagnosing the anteroposterior maxilo-mandibular relationship with CBCT. Study Design: Ninety patients who had previously a CBCT (i-CAT®) as a diagnostic register were selected. A 3D cephalometry was designed using one software package, InVivo5®. This cephalometry included 3 planes of reference, 3 angle measurements and 1 linear measurement. The means and standard deviations of the mean of each measurement were assessed. After that, a Pearson´s correlation coefficient has been performed to analyse the significance of each relationship. Results: When classifying the sample according to the anteroposterior relationship, the values obtained of ANB (Class I: 53%; Class II: 37%; Class III: 10%) and Wits (Class I: 35%; Class II: 56%; Class III: 9%) did not coincide, except for the Class III group. However, of the patients classified differently (Class I and Class II patients) by ANB and Wits, a high percentage of individuals (n=22; 49%), had a mesofacial pattern with a mandibular plane angle within normal values. A correlation has been found between ANB and Wits (r=0,262), occlusal plane angle and ANB (r=0,426), and mandibular plane angle and Wits (r=0,242). No correlation was found between either Wits or ANB in relation with the age of the individuals. Conclusions: ANB and Wits must be included in 3D cephalometric analyses as both are necessary to undertake a more accurate diagnosis of the maxillo-mandibular relationship of the patients. Key words:Cone beam computed tomography, ANB, Wits, cephalometrics. PMID:23722136

  11. Wings as impellers: honey bees co-opt flight system to induce nest ventilation and disperse pheromones.

    PubMed

    Peters, Jacob M; Gravish, Nick; Combes, Stacey A

    2017-06-15

    Honey bees ( Apis mellifera ) are remarkable fliers that regularly carry heavy loads of nectar and pollen, supported by a flight system - the wings, thorax and flight muscles - that one might assume is optimized for aerial locomotion. However, honey bees also use this system to perform other crucial tasks that are unrelated to flight. When ventilating the nest, bees grip the surface of the comb or nest entrance and fan their wings to drive airflow through the nest, and a similar wing-fanning behavior is used to disperse volatile pheromones from the Nasonov gland. In order to understand how the physical demands of these impeller-like behaviors differ from those of flight, we quantified the flapping kinematics and compared the frequency, amplitude and stroke plane angle during these non-flight behaviors with values reported for hovering honey bees. We also used a particle-based flow visualization technique to determine the direction and speed of airflow generated by a bee performing Nasonov scenting behavior. We found that ventilatory fanning behavior is kinematically distinct from both flight and scenting behavior. Both impeller-like behaviors drive flow parallel to the surface to which the bees are clinging, at typical speeds of just under 1 m s -1 We observed that the wings of fanning and scenting bees frequently contact the ground during the ventral stroke reversal, which may lead to wing wear. Finally, we observed that bees performing Nasonov scenting behavior sometimes display 'clap-and-fling' motions, in which the wings contact each other during the dorsal stroke reversal and fling apart at the start of the downstroke. We conclude that the wings and flight motor of honey bees comprise a multifunctional system, which may be subject to competing selective pressures because of its frequent use as both a propeller and an impeller. © 2017. Published by The Company of Biologists Ltd.

  12. Gait parameters associated with responsiveness to treadmill training with body-weight support after stroke: an exploratory study.

    PubMed

    Mulroy, Sara J; Klassen, Tara; Gronley, JoAnne K; Eberly, Valerie J; Brown, David A; Sullivan, Katherine J

    2010-02-01

    Task-specific training programs after stroke improve walking function, but it is not clear which biomechanical parameters of gait are most associated with improved walking speed. The purpose of this study was to identify gait parameters associated with improved walking speed after a locomotor training program that included body-weight-supported treadmill training (BWSTT). A prospective, between-subjects design was used. Fifteen people, ranging from approximately 9 months to 5 years after stroke, completed 1 of 3 different 6-week training regimens. These regimens consisted of 12 sessions of BWSTT alternated with 12 sessions of: lower-extremity resistive cycling; lower-extremity progressive, resistive strengthening; or a sham condition of arm ergometry. Gait analysis was conducted before and after the 6-week intervention program. Kinematics, kinetics, and electromyographic (EMG) activity were recorded from the hemiparetic lower extremity while participants walked at a self-selected pace. Changes in gait parameters were compared in participants who showed an increase in self-selected walking speed of greater than 0.08 m/s (high-response group) and in those with less improvement (low-response group). Compared with participants in the low-response group, those in the high-response group displayed greater increases in terminal stance hip extension angle and hip flexion power (product of net joint moment and angular velocity) after the intervention. The intensity of soleus muscle EMG activity during walking also was significantly higher in participants in the high-response group after the intervention. Only sagittal-plane parameters were assessed, and the sample size was small. Task-specific locomotor training alternated with strength training resulted in kinematic, kinetic, and muscle activation adaptations that were strongly associated with improved walking speed. Changes in both hip and ankle biomechanics during late stance were associated with greater increases in gait speed.

  13. Influence of surgical implantation angle of left ventricular assist device outflow graft and management of aortic valve opening on the risk of stroke in heart failure patients

    NASA Astrophysics Data System (ADS)

    Chivukula, V. Keshav; McGah, Patrick; Prisco, Anthony; Beckman, Jennifer; Mokadam, Nanush; Mahr, Claudius; Aliseda, Alberto

    2016-11-01

    Flow in the aortic vasculature may impact stroke risk in patients with left ventricular assist devices (LVAD) due to severely altered hemodynamics. Patient-specific 3D models of the aortic arch and great vessels were created with an LVAD outflow graft at 45, 60 and 90° from centerline of the ascending aorta, in order to understand the effect of surgical placement on hemodynamics and thrombotic risk. Intermittent aortic valve opening (once every five cardiac cycles) was simulated and the impact of this residual native output investigated for the potential to wash out stagnant flow in the aortic root region. Unsteady CFD simulations with patient-specific boundary conditions were performed. Particle tracking for 10 cardiac cycles was used to determine platelet residence times and shear stress histories. Thrombosis risk was assessed by a combination of Eulerian and Lagrangian metrics and a newly developed thrombogenic potential metric. Results show a strong influence of LVAD outflow graft angle on hemodynamics in the ascending aorta and consequently on stroke risk, with a highly positive impact of aortic valve opening, even at low frequencies. Optimization of LVAD implantation and management strategies based on patient-specific simulations to minimize stroke risk will be presented

  14. Linear-constraint wavefront control for exoplanet coronagraphic imaging systems

    NASA Astrophysics Data System (ADS)

    Sun, He; Eldorado Riggs, A. J.; Kasdin, N. Jeremy; Vanderbei, Robert J.; Groff, Tyler Dean

    2017-01-01

    A coronagraph is a leading technology for achieving high-contrast imaging of exoplanets in a space telescope. It uses a system of several masks to modify the diffraction and achieve extremely high contrast in the image plane around target stars. However, coronagraphic imaging systems are very sensitive to optical aberrations, so wavefront correction using deformable mirrors (DMs) is necessary to avoid contrast degradation in the image plane. Electric field conjugation (EFC) and Stroke minimization (SM) are two primary high-contrast wavefront controllers explored in the past decade. EFC minimizes the average contrast in the search areas while regularizing the strength of the control inputs. Stroke minimization calculates the minimum DM commands under the constraint that a target average contrast is achieved. Recently in the High Contrast Imaging Lab at Princeton University (HCIL), a new linear-constraint wavefront controller based on stroke minimization was developed and demonstrated using numerical simulation. Instead of only constraining the average contrast over the entire search area, the new controller constrains the electric field of each single pixel using linear programming, which could led to significant increases in speed of the wavefront correction and also create more uniform dark holes. As a follow-up of this work, another linear-constraint controller modified from EFC is demonstrated theoretically and numerically and the lab verification of the linear-constraint controllers is reported. Based on the simulation and lab results, the pros and cons of linear-constraint controllers are carefully compared with EFC and stroke minimization.

  15. The Subjective Postural Vertical Determined in Patients with Pusher Behavior During Standing.

    PubMed

    Bergmann, Jeannine; Krewer, Carmen; Selge, Charlotte; Müller, Friedemann; Jahn, Klaus

    2016-06-01

    The subjective postural vertical (SPV), i.e., the perceived upright orientation of the body in relation to gravity, is disturbed in patients with pusher behavior. So far, the SPV has been measured only when these patients were sitting, and the results were contradictory as regards the side of the SPV deviation. The objective was to investigate the SPV in patients with different degrees of severity of pusher behavior while standing. Eight stroke patients with pusher behavior, ten age-matched stroke patients without pusher behavior, and ten age-matched healthy control subjects were included. The SPV (SPV error, SPV range) was assessed in the pitch and the roll planes. Pusher behavior was classified with the Burke Lateropulsion Scale (BLS). In the pitch plane, the SPV range was significantly larger in pusher patients than in patients without pusher behavior or healthy controls. The SPV error was similar for groups. In the roll plane, the SPV error and the SPV range were significantly larger and more ipsilesionally tilted in the pusher group than in the other two groups. There was a significant correlation between the SPV error in the roll plane and the BLS score. The study revealed that patients with pusher behavior had an ipsilesional SPV tilt that decreased with decreasing severity of the behavior. The large uncertainty in verticality estimation in both planes indicates that their sensitivity for the perception of verticality in space is generally disturbed. These findings emphasize the importance of specific rehabilitation approaches to recalibrate the impaired inner model of verticality.

  16. Static performance investigation of a skewed-throat multiaxis thrust-vectoring nozzle concept

    NASA Technical Reports Server (NTRS)

    Wing, David J.

    1994-01-01

    The static performance of a jet exhaust nozzle which achieves multiaxis thrust vectoring by physically skewing the geometric throat has been characterized in the static test facility of the 16-Foot Transonic Tunnel at NASA Langley Research Center. The nozzle has an asymmetric internal geometry defined by four surfaces: a convergent-divergent upper surface with its ridge perpendicular to the nozzle centerline, a convergent-divergent lower surface with its ridge skewed relative to the nozzle centerline, an outwardly deflected sidewall, and a straight sidewall. The primary goal of the concept is to provide efficient yaw thrust vectoring by forcing the sonic plane (nozzle throat) to form at a yaw angle defined by the skewed ridge of the lower surface contour. A secondary goal is to provide multiaxis thrust vectoring by combining the skewed-throat yaw-vectoring concept with upper and lower pitch flap deflections. The geometric parameters varied in this investigation included lower surface ridge skew angle, nozzle expansion ratio (divergence angle), aspect ratio, pitch flap deflection angle, and sidewall deflection angle. Nozzle pressure ratio was varied from 2 to a high of 11.5 for some configurations. The results of the investigation indicate that efficient, substantial multiaxis thrust vectoring was achieved by the skewed-throat nozzle concept. However, certain control surface deflections destabilized the internal flow field, which resulted in substantial shifts in the position and orientation of the sonic plane and had an adverse effect on thrust-vectoring and weight flow characteristics. By increasing the expansion ratio, the location of the sonic plane was stabilized. The asymmetric design resulted in interdependent pitch and yaw thrust vectoring as well as nonzero thrust-vector angles with undeflected control surfaces. By skewing the ridges of both the upper and lower surface contours, the interdependency between pitch and yaw thrust vectoring may be eliminated and the location of the sonic plane may be further stabilized.

  17. The effect of ankle-foot orthosis plantarflexion stiffness on ankle and knee joint kinematics and kinetics during first and second rockers of gait in individuals with stroke

    PubMed Central

    Singer, Madeline L.; Kobayashi, Toshiki; Lincoln, Lucas S.; Orendurff, Michael S.; Foreman, K. Bo

    2014-01-01

    Background Stiffness of an ankle-foot orthosis plays an important role in improving gait in patients with a history of stroke. To address this, the aim of this case series study was to determine the effect of increasing plantarflexion stiffness of an ankle-foot orthosis on the sagittal ankle and knee joint angle and moment during the first and second rockers of gait. Methods Gait data were collected in 5 subjects with stroke at a self-selected walking speed under two plantarflexion stiffness conditions (0.4 Nm/deg and 1.3 Nm/deg) using a stiffness-adjustable experimental ankle-foot orthosis on a Bertec split-belt fully instrumented treadmill in a 3-dimensional motion analysis laboratory. Findings By increasing the plantarflexion stiffness of the ankle-foot orthosis, peak plantarfexion angle of the ankle was reduced and peak dorsiflexion moment was generally increased in the first rocker as hypothesized. Two subjects demonstrated increases in both peak knee flexion angle and peak knee extension moment in the second rocker as hypothesized. The two subjects exhibited minimum contractility during active plantarflexion, while the other three subjects could actively plantarflex their ankle joint. Interpretation It was suggested that those with the decreased ability to actively plantarflex their ankle could not overcome excessive plantarflexion stiffness at initial contact of gait, and as a result exhibited compensation strategies at the knee joint. Providing excessively stiff ankle-foot orthoses might put added stress on the extensor muscles of the knee joint, potentially creating fatigue and future pathologies in some patients with stroke. PMID:25241248

  18. Body configuration at first stepping-foot contact predicts backward balance recovery capacity in people with chronic stroke.

    PubMed

    de Kam, Digna; Roelofs, Jolanda M B; Geurts, Alexander C H; Weerdesteyn, Vivian

    2018-01-01

    To determine the predictive value of leg and trunk inclination angles at stepping-foot contact for the capacity to recover from a backward balance perturbation with a single step in people after stroke. Twenty-four chronic stroke survivors and 21 healthy controls were included in a cross-sectional study. We studied reactive stepping responses by subjecting participants to multidirectional stance perturbations at different intensities on a translating platform. In this paper we focus on backward perturbations. Participants were instructed to recover from the perturbations with maximally one step. A trial was classified as 'success' if balance was restored according to this instruction. We recorded full-body kinematics and computed: 1) body configuration parameters at first stepping-foot contact (leg and trunk inclination angles) and 2) spatiotemporal step parameters (step onset, step length, step duration and step velocity). We identified predictors of balance recovery capacity using a stepwise logistic regression. Perturbation intensity was also included as a predictor. The model with spatiotemporal parameters (perturbation intensity, step length and step duration) could correctly classify 85% of the trials as success or fail (Nagelkerke R2 = 0.61). In the body configuration model (Nagelkerke R2 = 0.71), perturbation intensity and leg and trunk angles correctly classified the outcome of 86% of the recovery attempts. The goodness of fit was significantly higher for the body configuration model compared to the model with spatiotemporal variables (p<0.01). Participant group and stepping leg (paretic or non-paretic) did not significantly improve the explained variance of the final body configuration model. Body configuration at stepping-foot contact is a valid and clinically feasible indicator of backward fall risk in stroke survivors, given its potential to be derived from a single sagittal screenshot.

  19. Sinus anatomy associated with inadvertent cerebrospinal fluid leak during functional endoscopic sinus surgery.

    PubMed

    Heaton, Chase M; Goldberg, Andrew N; Pletcher, Steven D; Glastonbury, Christine M

    2012-07-01

    Anatomic variations in skull base anatomy may predispose the surgeon to inadvertent skull base injury with resultant cerebrospinal fluid (CSF) leak during functional endoscopic sinus surgery (ESS). Our objective was to compare preoperative sinus imaging of patients who underwent FESS with and without CSF leak to elucidate these variations. In this retrospective case-control study, 18 patients with CSF leak following FESS for chronic rhinosinusitis (CRS) from 2000 to 2011 were compared to 18 randomly selected patients who underwent preoperative imaging for FESS for CRS. Measurements were obtained from preoperative computed tomography images with specific attention to anatomic differences in cribriform plate and ethmoid roof heights in the coronal plane, and the skull base angle in the sagittal plane. Mean values of measured variables were compared using a nonparametric Mann-Whitney test. When compared to controls, patients with CSF leak demonstrated a greater angle of the skull base in the sagittal plane (P < .001) and a greater slope of the skull base in the coronal plane (P < .006). A lower cribriform height relative to ethmoid roof height was also noted in cases of CSF leak as compared to controls (P < .04). A steep skull base angle in the sagittal plane, a greater slope of the skull base in the coronal plane, and a low cribriform height relative to the ethmoid roof predispose the patient to CSF leak during FESS. Preoperative review of imaging with specific attention paid to these anatomic variations may help to prevent iatrogenic CSF leak. Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.

  20. (E)-3-[2-(4-Chloro­phenyl­sulfon­yl)vin­yl]-6-methyl-4H-chromen-4-one

    PubMed Central

    Ravi Kumar, R.; Krishnaiah, M.; Oo, Thanzaw; Kaung, Pho; Jagadeesh Kumar, N.

    2009-01-01

    In the title compound, C18H13ClO4S, the mean planes of the chloro­phenyl ring and the S—C=C—C chain are oriented at angles of 52.7 (2) and 51.3 (2)°, respectively, with respect to the sulfonyl (O=S=O) plane. The dihedral angle between the mean planes of the chloro­phenyl group and the benzopyran ring is 80.7 (1)°. The crystal structure is stabilized by two inter­molecular C—H⋯O inter­actions, forming centrosymmetrc dimers, which are linked via a second C—H⋯O inter­action into a chain structure. PMID:21578354

  1. Dental and skeletal components of Class II open bite treatment with a modified Thurow appliance

    PubMed Central

    Jacob, Helder Baldi; dos Santos-Pinto, Ary; Buschang, Peter H.

    2014-01-01

    Introduction Due to the lack of studies that distinguish between dentoalveolar and basal changes caused by the Thurow appliance, this clinical study, carried out by the School of Dentistry - State University of São Paulo/Araraquara, aimed at assessing the dental and skeletal changes induced by modified Thurow appliance. Methods The sample included an experimental group comprising 13 subjects aged between 7 and 10 years old, with Class II malocclusion and anterior open bite, and a control group comprising 22 subjects similar in age, sex and mandibular plane angle. Maxillary/mandibular, horizontal/vertical, dental/skeletal movements (ANS, PNS, U1, U6, Co, Go, Pog, L1, L6) were assessed, based on 14 landmarks, 8 angles (S-N-ANS, SNA, PPA, S-N-Pog, SNB, MPA, PP/MPA, ANB) and 3 linear measures (N-Me, ANS-Me, S-Go). Results Treatment caused significantly greater angle decrease between the palatal and the mandibular plane of the experimental group, primarily due to an increase in the palatal plane angle. ANB, SNA and S-N-ANS angles significantly decreased more in patients from the experimental group. PNS was superiorly remodeled. Lower face height (ANS-Me) decreased in the experimental group and increased in the control group. Conclusions The modified Thurow appliance controlled vertical and horizontal displacements of the maxilla, rotated the maxilla and improved open bite malocclusion, decreasing lower facial height. PMID:24713556

  2. Force of resistance to pipeline pulling in plane and volumetrically curved wells

    NASA Astrophysics Data System (ADS)

    Toropov, V. S.; Toropov, S. Yu; Toropov, E. S.

    2018-05-01

    A method has been developed for calculating the component of the pulling force of a pipeline, arising from the well curvature in one or several planes, with the assumption that the pipeline is ballasted by filling with water or otherwise until zero buoyancy in the drilling mud is reached. This paper shows that when calculating this force, one can neglect the effect of sections with zero curvature. In the other case, if buoyancy of the pipeline is other than zero, the resistance force in the curvilinear sections should be calculated taking into account the difference between the normal components of the buoyancy force and weight. In the paper, it is proved that without taking into account resistance forces from the viscosity of the drilling mud, if buoyancy of the pipeline is zero, the total resistance force is independent of the length of the pipe and is determined by the angle equal to the sum of the entry angle and the exit angle of the pipeline to the day surface. For the case of the well curvature in several planes, it is proposed to perform the calculation of such volumetrically curved well by the central angle of the well profile. Analytical dependences are obtained that allow calculating the pulling force for well profiles with a variable curvature radius, i.e. at different angles of deviation between the drill pipes along the well profile.

  3. Orientation-dependent tensile deformation and damage of a T700 carbon fiber/epoxy composite: A synchrotron-based study

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

    Bie, B. X.; Huang, J. Y.; Fan, D.

    Uniaxial tensile experiments are conducted on a T700 carbon fiber/epoxy composite along various offaxis angles. Stressestrain curves are measured along with strain fields mapped via synchrotron x-ray digital image correlation, as well as computerized tomography. Elastic modulus and tensile strength decrease with increasing off-axis angles, while fracture strain exhibits a nonmonotonic trend as a combined result of tensile strength decrease and fracture mode transition. At high off-axis angles, strain field mapping demonstrates distinct tensile and shear strain localizations and deformation bands approximately along the fiber directions, while deformation is mainly achieved via continuous growth of tensile strain at low off-axismore » angles. Roughness of fracture planes decreases exponentially as the off-axis angle increases. The stressestrain curves, strain fields, tomography and fractographs show consistent features, and reveal a fracture mode transition from mainly tension (fiber fracture) to in-plane shear (interface debonding).« less

  4. Handrim wheelchair propulsion training effect on overground propulsion using biomechanical real-time visual feedback.

    PubMed

    Rice, Ian M; Pohlig, Ryan T; Gallagher, Jerri D; Boninger, Michael L

    2013-02-01

    To compare the effects of 2 manual wheelchair propulsion training programs on handrim kinetics, contact angle, and stroke frequency collected during overground propulsion. Randomized controlled trial comparing handrim kinetics between 3 groups: a control group that received no training, an instruction-only group that reviewed a multimedia presentation, and a feedback group that reviewed the multimedia presentation and real-time visual feedback. Research laboratory. Full-time manual wheelchair users (N=27) with spinal cord injury living in the Pittsburgh area. Propulsion training was given 3 times over 3 weeks, and data were collected at baseline, immediately after training, and at 3 months. Contact angle, stroke frequency, peak resultant force, and peak rate of rise of resultant force. Both feedback and instruction-only groups improved their propulsion biomechanics across all surfaces (carpet, tile, and ramp) at both target and self-selected speeds compared with the control group. While controlling for velocity, both intervention groups showed long-term reductions in the peak rate or rise of resultant force, stroke frequency, and increased contact angle. Long-term wheelchair users in both intervention groups significantly improved many aspects of their propulsion technique immediately after training and 3 months from baseline. Furthermore, training with a low-cost instructional video and slide presentation was an effective training tool alone. Copyright © 2013 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  5. 14 CFR 23.771 - Pilot compartment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the propellers so that no part of the pilot or the controls lies in the region between the plane of... propeller hub making an angle of 5 degrees forward or aft of the plane of rotation of the propeller. [Doc...

  6. Exercise-induced muscle fatigue in the unaffected knee joint and its influence on postural control and lower limb kinematics in stroke patients.

    PubMed

    Park, Sun Wook; Son, Sung Min; Lee, Na Kyung

    2017-05-01

    This study aimed to investigate the effects of exercise-induced muscle fatigue in the unaffected knee joint on postural control and kinematic changes in stroke patients. Forty participants (20 stroke patients, 20 age-matched healthy participants) were recruited. To induce fatigue, maximum voluntary isometric contractions were performed in the unaffected knee joint in a Leg Extension Rehab exercise machine using the pneumatic resistance. We measured static and dynamic balance and lower-limb kinematics during gait. Changes in postural control parameters anteroposterior sway speed and total center of pressure distance differed significantly between the stroke and control groups. In addition, changes in gait kinematic parameters knee and ankle angles of initial contact differed significantly between stroke (paretic and non-paretic) and control groups. Muscle fatigue in the unaffected knee and ankle impaired postural control and debilitates kinematic movement of ipsilateral and contralateral lower limbs, and may place the fatigued stroke patients at greater risk for falls.

  7. Dependence of reflection and transmission of soliton on angle of incidence at an interface between chalcogenide fibre and gallium nanoparticle film by phase plane trajectories

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

    Naruka, Preeti, E-mail: preety-naruka@Yyahoo.co.in; Bissa, Shivangi; Nagar, A. K.

    In the present paper, we study propagation of a soliton at an interface formed between special type of chalcogenide fibre and gallium in three different phases with the help of equivalent particle theory. Critical angle of incidence and critical power required for transmission and reflection of soliton beam have investigated. Here it is found that if the incident angle of the beam or initial velocity of the equivalent particle is insufficient to overcome the maximum increase in potential energy then the particle (light beam) is reflected by the interface and if this incident angle is greater than a critical anglemore » then light beam will be transmitted by the interface. From an equation these critical angles for α-gallium, one of a metastable phase and liquid gallium are calculated and concluded that at large incident angles, the soliton is transmitted through the boundary, whereas at small incidence angles the soliton get reflected on keeping the power of incident beam constant. These results are explained by phase plane trajectories of the effective potential which are experimentally as well as theoretically proved.« less

  8. Comment on "Experimental study of the orientation dependence of indium incorporation in GaInN" [J. Cryst. Growth 433 (2016) 7-12

    NASA Astrophysics Data System (ADS)

    Monavarian, Morteza

    2016-07-01

    The authors of the title paper (J. Cryst. Growth 433 (2016) 7-12) reported on experimental comparison of indium incorporation efficiency in wide variety of orientations tilted from the basal plane toward a-plane (a-family planes) or m-plane (m-family planes) and some mixed planes. Despite a good investigation and useful information reported in this manuscript, some points of criticism, concerning the inclination angle calculations, optical characterizations of the layers, and the final conclusions are highlighted in this comment to consider.

  9. Is the low-l microwave background cosmic?

    PubMed

    Schwarz, Dominik J; Starkman, Glenn D; Huterer, Dragan; Copi, Craig J

    2004-11-26

    The large-angle (low-l) correlations of the cosmic microwave background exhibit several statistically significant anomalies compared to the standard inflationary cosmology. We show that the quadrupole plane and the three octopole planes are far more aligned than previously thought (99.9% C.L.). Three of these planes are orthogonal to the ecliptic at 99.1% C.L., and the normals to these planes are aligned at 99.6% C.L. with the direction of the cosmological dipole and with the equinoxes. The remaining octopole plane is orthogonal to the supergalactic plane at 99.6% C.L.

  10. Tidal Friction in the Earth-Moon System and Laplace Planes: Darwin Redux

    NASA Technical Reports Server (NTRS)

    Rubincam, David P.

    2015-01-01

    The dynamical evolution of the Earth-Moon system due to tidal friction is treated here. George H. Darwin used Laplace planes (also called proper planes) in his study of tidal evolution. The Laplace plane approach is adapted here to the formalisms of W.M. Kaula and P. Goldreich. Like Darwin, the approach assumes a three-body problem: Earth, Moon, and Sun, where the Moon and Sun are point-masses. The tidal potential is written in terms of the Laplace plane angles. The resulting secular equations of motion can be easily integrated numerically assuming the Moon is in a circular orbit about the Earth and the Earth is in a circular orbit about the Sun. For Earth-Moon distances greater than 10 Earth radii, the Earth's approximate tidal response can be characterized with a single parameter, which is a ratio: a Love number times the sine of a lag angle divided by another such product. For low parameter values it can be shown that Darwin's low-viscosity molten Earth, M. Ross's and G. Schubert's model of an Earth near melting, and Goldreich's equal tidal lag angles must all give similar histories. For higher parameter values, as perhaps has been the case at times with the ocean tides, the Earth's obliquity may have decreased slightly instead of increased once the Moon's orbit evolved further than 50 Earth radii from the Earth, with possible implications for climate. This is contrast to the other tidal friction models mentioned, which have the obliquity always increasing with time. As for the Moon, its orbit is presently tilted to its Laplace plane by 5.2deg. The equations do not allow the Moon to evolve out of its Laplace plane by tidal friction alone, so that if it was originally in its Laplace plane, the tilt arose with the addition of other mechanisms, such as resonance passages.

  11. Does hemipelvis structure and position influence acetabulum orientation?

    PubMed

    Musielak, Bartosz; Jóźwiak, Marek; Rychlik, Michał; Chen, Brian Po-Jung; Idzior, Maciej; Grzegorzewski, Andrzej

    2016-03-16

    Although acetabulum orientation is well established anatomically and radiographically, its relation to the innominate bone has rarely been addressed. If explored, it could open the discussion on patomechanisms of such complex disorders as femoroacetabular impingement (FAI). We therefore evaluated the influence of pelvic bone position and structure on acetabular spatial orientation. We describe this relation and its clinical implications. This retrospective study was based on computed tomography scanning of three-dimensional models of 31 consecutive male pelvises (62 acetabulums). All measurements were based on CT spatial reconstruction with the use of highly specialized software (Rhinoceros). Relations between acetabular orientation (inclination, tilt, anteversion angles) and pelvic structure were evaluated. The following parameters were evaluated to assess the pelvic structure: iliac opening angle, iliac tilt angle, interspinous distance (ISD), intertuberous distance (ITD), height of the pelvis (HP), and the ISD/ITD/HP ratio. The linear and nonlinear dependence of the acetabular angles and hemipelvic measurements were examined with Pearson's product - moment correlation and Spearman's rank correlation coefficient. Correlations different from 0 with p < 0.05 were considered statistically significant. Comparison of the axis position with pelvis structure with orientation in the horizontal plane revealed a significant positive correlation between the acetabular anteversion angle and the iliac opening angle (p = 0.041 and 0.008, respectively). In the frontal plane, there was a positive correlation between the acetabular inclination angle and the iliac tilt angle (p = 0.025 and 0.014, respectively) and the acetabular inclination angle and the ISD/ITD/HP ratio (both p = 0.048). There is a significant correlation of the hemipelvic structure and acetabular orientation under anatomic conditions, especially in the frontal and horizontal planes. In the anteroposterior view, the more tilted-down innominate bone causes a more caudally oriented acetabulum axis, whereas in the horizontal view this relation is reversed. This study may serve as a basis for the discussion on the role of the pelvis in common disorders of the hip.

  12. Three paths toward the quantum angle operator

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

    Gazeau, Jean Pierre, E-mail: gazeau@apc.univ-paris7.fr; Szafraniec, Franciszek Hugon, E-mail: franciszek.szafraniec@uj.edu.pl

    2016-12-15

    We examine mathematical questions around angle (or phase) operator associated with a number operator through a short list of basic requirements. We implement three methods of construction of quantum angle. The first one is based on operator theory and parallels the definition of angle for the upper half-circle through its cosine and completed by a sign inversion. The two other methods are integral quantization generalizing in a certain sense the Berezin–Klauder approaches. One method pertains to Weyl–Heisenberg integral quantization of the plane viewed as the phase space of the motion on the line. It depends on a family of “weight”more » functions on the plane. The third method rests upon coherent state quantization of the cylinder viewed as the phase space of the motion on the circle. The construction of these coherent states depends on a family of probability distributions on the line.« less

  13. Magnetic droplet soliton nucleation in oblique fields

    NASA Astrophysics Data System (ADS)

    Mohseni, Morteza; Hamdi, M.; Yazdi, H. F.; Banuazizi, S. A. H.; Chung, S.; Sani, S. R.; Åkerman, Johan; Mohseni, Majid

    2018-05-01

    We study the auto-oscillating magnetodynamics in orthogonal spin-torque nano-oscillators (STNOs) as a function of the out-of-plane (OOP) magnetic-field angle. In perpendicular fields and at OOP field angles down to approximately 50°, we observe the nucleation of a droplet. However, for field angles below 50°, experiments indicate that the droplet gives way to propagating spin waves, in agreement with our micromagnetic simulations. Theoretical calculations show that the physical mechanism behind these observations is the sign changing of spin-wave nonlinearity (SWN) by angle. In addition, we show that the presence of a strong perpendicular magnetic anisotropy free layer in the system reverses the angular dependence of the SWN and dynamics in STNOs with respect to the known behavior determined for the in-plane magnetic anisotropy free layer. Our results are of fundamental interest in understanding the rich dynamics of nanoscale solitons and spin-wave dynamics in STNOs.

  14. Comparison of cardiovascular function during the early hours of bed rest and space flight

    NASA Technical Reports Server (NTRS)

    Lathers, C. M.; Charles, J. B.

    1994-01-01

    This paper reviews the cardiovascular responses of six healthy male subjects to 6 hours in a 5 degrees head-down bed rest model of weightlessness, and compares these responses to those obtained when subjects were positioned in head-up tilts of 10 degrees, 20 degrees, and 42 degrees, simulating 1/6, 1/3, and 2/3 G, respectively. Thoracic fluid index, cardiac output, stroke volume, and peak flow were measured using impedance cardiography. Cardiac dimensions and volumes were determined from two-dimensional guided M-mode echocardiograms in the left lateral decubitus position at 0, 2, 4, and 6 hours. Cardiovascular response to a stand test were compared before and after bed rest. The impedance values were related to tilt angle for the first 2 hours of tilt; however, after 3 hours, at all four angles, values began to converge, indicating that cardiovascular homeostatic mechanisms seek a common adapted state, regardless of effective gravity level (tilt angle) up to 2/3 G. Echocardiography revealed that left ventricular end-diastolic and end-systolic volume, stroke volume, ejection fraction, heart rate, and cardiac output had returned to control values by hour 6 for all tilt angles. The lack of a significant immediate change in left ventricular end-diastolic volume, despite decrements in stroke volume (P < .05) and heart rate (not significant), indicates that multiple factors may play a role in the adaptation to simulated hypogravity. The echocardiography data indicated that no angle of tilt, whether head-down or head-up for 4 to 6 hours, mimicked exactly the changes in cardiovascular function recorded after 4 to 6 hours of space flight. Changes in left ventricular end-diastolic volume during space flight and tilt may be similar, but follow a different time course. Nevertheless, head-down tilt at 5 degrees for 6 hours mimics some (stroke volume, systolic and diastolic blood pressure, mean arterial blood pressure, and total resistance), but not all, of the changes occurring in an equivalent time of space flight. The magnitude of the change in the mean heart rate response to standing was greater after six hours of tilt at -5 degrees or 10 degrees. Thus, results from the stand test after 6 hours of bed rest at -5 degrees and 10 degrees, but not at 20 degrees or 42 degrees, are similar to those obtained after space flight.

  15. Comparison of three facebow/semi-adjustable articulator systems for planning orthognathic surgery.

    PubMed

    O'Malley, A M; Milosevic, A

    2000-06-01

    Our aim was to measure the steepness of the occlusal plane produced by three different semi-adjustable articulators: the Dentatus Type ARL, Denar MkII, and the Whipmix Quickmount 8800, and to assess the influence of possible systematic errors in positioning of study casts on articulators that are used to plan orthognathic surgery. Twenty patients (10 skeletal class II, and 10 skeletal class III) who were having pre-surgical orthodontics at Liverpool University Dental Hospital were studied. The measurement of the steepness of the occlusal plane was taken as the angle between the facebow bite-fork and the horizontal arm of the articulator. This was compared with the angle of the maxillary occlusal plane to the Frankfort plane as measured on lateral cephalometry (the gold standard). The Whipmix was closest to the gold standard as it flattened the occlusal plane by only 2 degrees (P<0.05). The results of the Denar and Dentatus differed significantly from those of the cephalogram as they flattened the occlusal plane by 5 degrees and 6. 5 degrees (P<0.01), respectively. Clinicians are encouraged to verify the steepness of the occlusal plane on mounted study casts before the technician makes the model. Copyright 2000 The British Association of Oral and Maxillofacial Surgeons.

  16. Optics: Light, Color, and Their Uses. An Educator's Guide with Activities in Science and Mathematics.

    ERIC Educational Resources Information Center

    National Aeronautics and Space Administration, Huntsville, AL. George C. Marshall Space Flight Center.

    This educator's guide from discusses optics, light, color and their uses. Activities include: (1) "Reflection of Light with a Plane (Flat) Mirror--Trace a Star"; (2) "Reflection of Light with Two Plane Mirrors--Double Mirrors Placed at a 90-Degree Angle"; (3) "Reflection of Light with Two Plane Mirrors--Double Mirrors Placed at a Number of…

  17. Magnetic domains in Tb-Fe-Co thin films under anisotropy tilt

    NASA Astrophysics Data System (ADS)

    Talapatra, A.; Umadevi, K.; Arout Chelvane, J.; Mohanty, J.; Jayalakshmi, V.

    2018-04-01

    Tailoring of magnetic domains of Tb-Fe-Co thin films with rapid thermal processing has been reported in this paper. While the as-deposited films show elongated, inter-connected domains with high out-of-plane magnetic phase contrast, the rapid thermal processed films at 550 °C with different time intervals display deterioration of magnetic contrast. A longitudinal extension of domains has been observed with the processing time of 5 min. With subsequent increase in processing time, the domain patterns exhibit considerable decrease in magnetic phase difference combined with strong intermixing between two oppositely magnetized areas. The out-of-plane magnetic contrast is seen to be very weak for the Tb-Fe-Co film processed for 30 min. The domain morphology and the contrast variation have been modeled with micromagnetic simulations, considering the in-plane (along xz plane) tilt of anisotropy axis. The ground state energy profile and the variation in magnetic properties indicate the threshold tilt angle to be around 30 ° wherein the in-plane and out-of-plane squareness ratio and coercivities are comparable and hence the system shows a spin re-orientation behavior at higher tilt angles.

  18. Stress waves in transversely isotropic media: The homogeneous problem

    NASA Technical Reports Server (NTRS)

    Marques, E. R. C.; Williams, J. H., Jr.

    1986-01-01

    The homogeneous problem of stress wave propagation in unbounded transversely isotropic media is analyzed. By adopting plane wave solutions, the conditions for the existence of the solution are established in terms of phase velocities and directions of particle displacements. Dispersion relations and group velocities are derived from the phase velocity expressions. The deviation angles (e.g., angles between the normals to the adopted plane waves and the actual directions of their propagation) are numerically determined for a specific fiber-glass epoxy composite. A graphical method is introduced for the construction of the wave surfaces using magnitudes of phase velocities and deviation angles. The results for the case of isotropic media are shown to be contained in the solutions for the transversely isotropic media.

  19. (1R,4R,7S)-1,7-Dimethyl-7-(phenyl­sulfonyl­meth­yl)spiro­[bicyclo­[2.2.1]heptane-2,2′-1,3-dioxolane

    PubMed Central

    Wang, Ya-Wen; Peng, Yu

    2008-01-01

    In the title compound, C18H24O4S, the chiral bicyclo­[2.2.1]heptane group is not symmetrical due to the influence of the substituents. The angle between the three-atom bridge plane and the four-atom planes of the boat-shaped six-membered ring are 55.07 (19) and 56.24 (19)°. The bridgehead angle is 92.75 (17)°. PMID:21200933

  20. A reconstruction algorithm for helical CT imaging on PI-planes.

    PubMed

    Liang, Hongzhu; Zhang, Cishen; Yan, Ming

    2006-01-01

    In this paper, a Feldkamp type approximate reconstruction algorithm is presented for helical cone-beam Computed Tomography. To effectively suppress artifacts due to large cone angle scanning, it is proposed to reconstruct the object point-wisely on unique customized tilted PI-planes which are close to the data collecting helices of the corresponding points. Such a reconstruction scheme can considerably suppress the artifacts in the cone-angle scanning. Computer simulations show that the proposed algorithm can provide improved imaging performance compared with the existing approximate cone-beam reconstruction algorithms.

  1. Effects of Rock Joints on Failure of Tunnels Subject to Blast Loading

    DTIC Science & Technology

    2013-11-01

    The out of plane component of stress , if present, is denoted by σ33, associated with an orthonormal basis vector e3. The principal directions of stress ...lies within the plane of stress or strain, and forms an angle, θ, with respect to the first principal direction p1. Define the normal vector to the...surface of material failure by the critical angle, θc. For the regime (a), (b), (c)-(d), n is equal to p1, the direction of maximum principal stress

  2. A Theoretical and Experimental Study of Planing Surfaces Including Effects of Cross Section and Plan Form

    NASA Technical Reports Server (NTRS)

    Shuford, Charles L , Jr

    1958-01-01

    A summary is given of the background and present status of the pure-planing theory for rectangular flat plates and v-bottom surfaces. The equations reviewed are compared with experiment. In order to extend the range of available planing data, the principal planing characteristics for models having sharp bottom surfaces having constant angles of dead rise of 20 degrees and 40 degrees. Planing data were also obtained for flat-plate surfaces with very slightly rounded chines for which decreased lift and drag coefficients are obtained.

  3. 14 CFR 23.1395 - Maximum intensities in overlapping beams of position lights.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... boundary plane at more than 10 degrees but less than 20 degrees; and (b) Area B includes all directions in the adjacent dihedral angle that pass through the light source and intersect the common boundary plane...

  4. Plane Jane(s).

    ERIC Educational Resources Information Center

    Greenman, Geri

    2001-01-01

    Describes an assignment that was used in an advanced drawing class in which the students created self-portraits, breaking up their images using planes and angles to suggest their bone structure. Explains that the students also had to include three realistic portions in their drawings. (CMK)

  5. Transverse plane of apical vertebra of structural thoracic curve: vertebra displacement versus vertebral deformation.

    PubMed

    Kotwicki, Tomasz; Napiontek, Marek; Nowakowski, Andrzej

    2006-01-01

    CT transversal scans of the trunk provided at the level of Th8 or Th9 (apical vertebra) of 23 patients with structural thoracic scoliosis were reviewed. The following parameters were studied: 1) alpha angle formed by the axis of vertebra and the axis of spinous process, 2) beta concave and beta convex angle between the spinous process and the left and right transverse process respectively, 3) gamma concave and gamma convex angle between the axis of vertebra and the left and right transverse process respectively, 4) rotation angle to the sagittal plane according to Aaro and Dahlborn, 5) Cobb angle. Values of measured parameters demonstrated a common pattern of intravertebral deformity: counter clockwise deviation of the spinous process (alpha angle 15,0 +/-8,5 degrees), beta concave (69,8 +/-8,5 degrees) significantly greater than beta convex (38,8 +/-8,5 degrees), gamma concave (54,3 +/-7,8 degrees) not different from gamma convex (56,0 +/-8,0 degrees). Strong linear positive correlation between alpha angle and Aaro-Dahlborn angle was observed (r=0,78, p<0,05). Changes in morphology of apical vertebra due to intravertebral bone remodelling followed the vertebral spatial displacement and there existed a linear correlation in between. The two processes develop in opposite directions.

  6. Myoelectrically controlled wrist robot for stroke rehabilitation

    PubMed Central

    2013-01-01

    Background Robot-assisted rehabilitation is an advanced new technology in stroke rehabilitation to provide intensive training. Post-stroke motor recovery depends on active rehabilitation by voluntary participation of patient’s paretic motor system as early as possible in order to promote reorganization of brain. However, voluntary residual motor efforts to the affected limb have not been involved enough in most robot-assisted rehabilitation for patients after stroke. The objective of this study is to evaluate the feasibility of robot-assisted rehabilitation using myoelectric control on upper limb motor recovery. Methods In the present study, an exoskeleton-type rehabilitation robotic system was designed to provide voluntarily controlled assisted torque to the affected wrist. Voluntary intention was involved by using the residual surface electromyography (EMG) from flexor carpi radialis(FCR) and extensor carpi radialis (ECR)on the affected limb to control the mechanical assistance provided by the robotic system during wrist flexion and extension in a 20-session training. The system also applied constant resistant torque to the affected wrist during the training. Sixteen subjects after stroke had been recruited for evaluating the tracking performance and therapeutical effects of myoelectrically controlled robotic system. Results With the myoelectrically-controlled assistive torque, stroke survivors could reach a larger range of motion with a significant decrease in the EMG signal from the agonist muscles. The stroke survivors could be trained in the unreached range with their voluntary residual EMG on the paretic side. After 20-session rehabilitation training, there was a non-significant increase in the range of motion and a significant decrease in the root mean square error (RMSE) between the actual wrist angle and target angle. Significant improvements also could be found in muscle strength and clinical scales. Conclusions These results indicate that robot-aided therapy with voluntary participation of patient’s paretic motor system using myoelectric control might have positive effect on upper limb motor recovery. PMID:23758925

  7. Anisotropic spin-density distribution and magnetic anisotropy of strained La1-xSrxMnO3 thin films: angle-dependent x-ray magnetic circular dichroism

    NASA Astrophysics Data System (ADS)

    Shibata, Goro; Kitamura, Miho; Minohara, Makoto; Yoshimatsu, Kohei; Kadono, Toshiharu; Ishigami, Keisuke; Harano, Takayuki; Takahashi, Yukio; Sakamoto, Shoya; Nonaka, Yosuke; Ikeda, Keisuke; Chi, Zhendong; Furuse, Mitsuho; Fuchino, Shuichiro; Okano, Makoto; Fujihira, Jun-ichi; Uchida, Akira; Watanabe, Kazunori; Fujihira, Hideyuki; Fujihira, Seiichi; Tanaka, Arata; Kumigashira, Hiroshi; Koide, Tsuneharu; Fujimori, Atsushi

    2018-01-01

    Magnetic anisotropies of ferromagnetic thin films are induced by epitaxial strain from the substrate via strain-induced anisotropy in the orbital magnetic moment and that in the spatial distribution of spin-polarized electrons. However, the preferential orbital occupation in ferromagnetic metallic La1-xSrxMnO3 (LSMO) thin films studied by x-ray linear dichroism (XLD) has always been found out-of-plane for both tensile and compressive epitaxial strain and hence irrespective of the magnetic anisotropy. In order to resolve this mystery, we directly probed the preferential orbital occupation of spin-polarized electrons in LSMO thin films under strain by angle-dependent x-ray magnetic circular dichroism (XMCD). Anisotropy of the spin-density distribution was found to be in-plane for the tensile strain and out-of-plane for the compressive strain, consistent with the observed magnetic anisotropy. The ubiquitous out-of-plane preferential orbital occupation seen by XLD is attributed to the occupation of both spin-up and spin-down out-of-plane orbitals in the surface magnetic dead layer.

  8. A patient-controlled functional electrical stimulation system for arm weight relief.

    PubMed

    Klauer, C; Ferrante, S; Ambrosini, E; Shiri, U; Dähne, F; Schmehl, I; Pedrocchi, A; Schauer, T

    2016-11-01

    A patient-driven control strategy for Functional Electrical Stimulation (FES), which amplifies volitionally-initiated shoulder abductions, is proposed to improve stroke patients' rehabilitation. Based on the measured abduction angle, a FES-induced muscle recruitment is generated that yields a pre-specified percentage of this angle - yielding arm weight relief. To guarantee the correct recruitment also under fatigue and uncertain muscle activation we employ feedback control of the recruitment level determined by filtering the FES-evoked electromyogram. Filter parameters are user-optimized to obtain a linear relation between filter output and angle with a good signal-to-noise ratio. The auto-tuned recruitment controller (RC) was tested on five healthy subjects and compared to direct stimulation (DS) while muscle fatigue progressively occurred. Results showed a more linear relation between recruitment level and angle than between non-controlled stimulation intensity and angle (R 2 =0.93 vs. R 2 =0.79, angular range of 54°). After 6 min of stimulation, abduction decreased by 42% ± 14 for DS and by 0% ± 12 for RC, showing an effective compensation of fatigue. RC yielded significant smaller errors than DS in generating desired angles (0.23% ± 5.9 vs. 14.6% ± 9.7). When FES-induced arm weight support was provided, a mean reduction of the volitional effort (determined by Electromyography) of 78% was achieved compared to angular tracking without FES. First experiments with one acute stroke patient are also reported. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

  9. Inertial Measurement Units for Clinical Movement Analysis: Reliability and Concurrent Validity

    PubMed Central

    Nicholas, Kevin; Sparkes, Valerie; Sheeran, Liba; Davies, Jennifer L

    2018-01-01

    The aim of this study was to investigate the reliability and concurrent validity of a commercially available Xsens MVN BIOMECH inertial-sensor-based motion capture system during clinically relevant functional activities. A clinician with no prior experience of motion capture technologies and an experienced clinical movement scientist each assessed 26 healthy participants within each of two sessions using a camera-based motion capture system and the MVN BIOMECH system. Participants performed overground walking, squatting, and jumping. Sessions were separated by 4 ± 3 days. Reliability was evaluated using intraclass correlation coefficient and standard error of measurement, and validity was evaluated using the coefficient of multiple correlation and the linear fit method. Day-to-day reliability was generally fair-to-excellent in all three planes for hip, knee, and ankle joint angles in all three tasks. Within-day (between-rater) reliability was fair-to-excellent in all three planes during walking and squatting, and poor-to-high during jumping. Validity was excellent in the sagittal plane for hip, knee, and ankle joint angles in all three tasks and acceptable in frontal and transverse planes in squat and jump activity across joints. Our results suggest that the MVN BIOMECH system can be used by a clinician to quantify lower-limb joint angles in clinically relevant movements. PMID:29495600

  10. Separation of Migration and Tomography Modes of Full-Waveform Inversion in the Plane Wave Domain

    NASA Astrophysics Data System (ADS)

    Yao, Gang; da Silva, Nuno V.; Warner, Michael; Kalinicheva, Tatiana

    2018-02-01

    Full-waveform inversion (FWI) includes both migration and tomography modes. The migration mode acts like a nonlinear least squares migration to map model interfaces with reflections, while the tomography mode behaves as tomography to build a background velocity model. The migration mode is the main response of inverting reflections, while the tomography mode exists in response to inverting both the reflections and refractions. To emphasize one of the two modes in FWI, especially for inverting reflections, the separation of the two modes in the gradient of FWI is required. Here we present a new method to achieve this separation with an angle-dependent filtering technique in the plane wave domain. We first transform the source and residual wavefields into the plane wave domain with the Fourier transform and then decompose them into the migration and tomography components using the opening angles between the transformed source and residual plane waves. The opening angles close to 180° contribute to the tomography component, while the others correspond to the migration component. We find that this approach is very effective and robust even when the medium is relatively complicated with strong lateral heterogeneities, highly dipping reflectors, and strong anisotropy. This is well demonstrated by theoretical analysis and numerical tests with a synthetic data set and a field data set.

  11. Self-latching eccentric cam for dual stroke compressor or pump

    DOEpatents

    Sisk, Francis J.

    1985-01-01

    For a dual capacity refrigerant compressor of the type which has an eccentric cam rotatable on a crankpin between two opposite positions which changes the total eccentricity of the crankpin and cam so as to obtain two different stroke lengths, the rotation of the cam on the crankpin being effected by a reversal of motor operation, the cam moves through an angle of about 270.degree. around the crankpin so that a centrifugal force torque tending to hold the cam in place is available at least in the reduced stroke length position of the cam, and by providing lightening cavities and eccentric weightings, the center of mass 74 of the cam can be shifted to obtain the centrifugal torque in the proper direction at both the maximum and reduced stroke positions.

  12. Self-latching eccentric cam for dual stroke compressor or pump

    DOEpatents

    Sisk, F.J.

    1985-01-22

    For a dual capacity refrigerant compressor of the type which has an eccentric cam rotatable on a crankpin between two opposite positions which changes the total eccentricity of the crankpin and cam so as to obtain two different stroke lengths, the rotation of the cam on the crankpin being effected by a reversal of motor operation, the cam moves through an angle of about 270[degree] around the crankpin so that a centrifugal force torque tending to hold the cam in place is available at least in the reduced stroke length position of the cam, and by providing lightening cavities and eccentric weightings, the center of mass of the cam can be shifted to obtain the centrifugal torque in the proper direction at both the maximum and reduced stroke positions. 7 figs.

  13. Geometric analysis of the V-Y advancement flap and its clinical applications.

    PubMed

    Andrades, Patricio R; Calderon, Wilfredo; Leniz, Patricio; Bartel, German; Danilla, Stefan; Benitez, Susana

    2005-05-01

    Geometry is fundamental in the comprehension of local flap design. The purpose of this study was to discuss the differences between the V-Y advancement flap and other local flaps, understand its geometry, and analyze its clinical applications. The analysis was based on qualitative measurements of an injury, taking into consideration the following dimensions: largest diameter, shortest diameter, and depth. Standardization of the flap design consisted of directing its advancement over the shortest diameter and making the V base match the size of the largest diameter. The flap was analyzed in two planes: the horizontal plane includes the V-Y design and the vertical plane includes the flap pedicle. The height of the flap can be obtained by simple trigonometry, taking into consideration the largest diameter and alpha angle in the horizontal plane. In the vertical plane, where the pedicle and pivot plane are positioned, for known shortest diameter and depth, the final depth of the pivot plane can be calculated using Pythagoras' principles. This analysis was applied to 25 patients with adequate skin coverage at follow-up. A correction factor was added to reduce the overdeepening of the vertical plane calculations. The final concepts for clinical application in the classic deep pedicle V-Y flap design are to calculate the length of the V by modifying the alpha angle and to move the pivot plane deeper to accomplish optimal flap movement. Using these principles, tension-free closure of the Y and appropriate advancement of the flap are obtained.

  14. Surface anatomy and anatomical planes in the adult turkish population.

    PubMed

    Uzun, C; Atman, E D; Ustuner, E; Mirjalili, S A; Oztuna, D; Esmer, T S

    2016-03-01

    Surface anatomy and anatomical planes are widely used in education and clinical practice. The planes are largely derived from cadaveric studies and their projections on the skin show discrepancies between and within anatomical reference textbooks. In this study, we reassessed the accuracy of common thoracic and abdominopelvic anatomical planes using computed tomography (CT) imaging in the live adult Turkish population. After patients with distorting pathologies had been excluded, CT images of 150 supine patients at the end tidal inspiration were analyzed. Sternal angle, transpyloric, subcostal, supracristal and pubic crest planes and their relationships to anatomical structures were established by dual consensus. The tracheal bifurcation, azygos vein/superior vena cava (SVC) junction and pulmonary bifurcation were usually below the sternal angle while the concavity of the aortic arch was generally within the plane. The tip of the tenth rib, the superior mesenteric artery and the portal vein were usually within the transpyloric plane while the renal hila and the fundus of the gallbladder were below it. The inferior mesenteric artery was below the subcostal plane and the aortic bifurcation was below the supracristal plane in most adults. Projectional surface anatomy is fundamental to medical education and clinical practice. Modern cross-sectional imaging techniques allow large groups of live patients to be examined. Classic textbook information regarding anatomy needs to be reviewed and updated using the data gathered from these recent studies, taking ethnic differences into consideration. © 2015 Wiley Periodicals, Inc.

  15. A Comparative Analysis of Swimming Styles in Competitive Swimming

    NASA Astrophysics Data System (ADS)

    von Loebbecke, Alfred; Mittal, Rajat; Gupta, Varun; Mark, Russell

    2007-11-01

    High-fidelity numerical simulations are being used to conduct a critical evaluation of swimming strokes in competitive swimming. We combine computational fluid dynamics (CFD), laser body scans, animation software, and video footage to develop accurate models of Olympic level swimmers and use these to examine contrasting styles of the dolphin kick as well as the arm strokes in back and front crawl stroke. In the dolphin kick, the focus is on examining the effects of Strouhal number, kick amplitude, frequency, and technique on thrust production. In the back stroke, we examine the performance of the so called ``flat stroke'' versus the ``deep catch,'' The most important aspect that separates the two major types of back stroke is the alignment or angle of attack of the palm during the stroke. In one style of front crawl arm stroke, there is greater elbow joint flexion, shoulder abduction and sculling whereas the other style consists of a straight arm pull dominated by simple shoulder flexion. Underlying the use of these two styles is the larger and more fundamental issue of the role of lift versus drag in thrust production and we use the current simulations to examine this issue in detail.

  16. 14 CFR 27.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... boundary plane at more than 10 degrees but less than 20 degrees, and (b) Area B includes all directions in the adjacent dihedral angle that pass through the light source and intersect the common boundary plane...

  17. 14 CFR 25.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... boundary plane at more than 10 degrees but less than 20 degrees; and (b) Area B includes all directions in the adjacent dihedral angle that pass through the light source and intersect the common boundary plane...

  18. 14 CFR 29.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... boundary plane at more than 10 degrees but less than 20 degrees; and (b) Area B includes all directions in the adjacent dihedral angle that pass through the light source and intersect the common boundary plane...

  19. Optical scatter imaging of cellular and mitochondrial swelling in brain tissue models of stroke

    NASA Astrophysics Data System (ADS)

    Johnson, Lee James

    2001-08-01

    The severity of brain edema resulting from a stroke can determine a patient's survival and the extent of their recovery. Cellular swelling is the microscopic source of a significant part of brain edema. Mitochondrial swelling also appears to be a determining event in the death or survival of the cells that are injured during a stroke. Therapies for reducing brain edema are not effective in many cases and current treatments of stroke do not address mitochondrial swelling at all. This dissertation is motivated by the lack of a complete understanding of cellular swelling resulting from stroke and the lack of a good method to begin to study mitochondrial swelling resulting from stroke in living brain tissue. In this dissertation, a novel method of detecting mitochondrial and cellular swelling in living hippocampal slices is developed and validated. The system is used to obtain spatial and temporal information about cellular and mitochondrial swelling resulting from various models of stroke. The effect of changes in water content on light scatter and absorption are examined in two models of brain edema. The results of this study demonstrate that optical techniques can be used to detect changes in water content. Mie scatter theory, the theoretical basis of the dual- angle scatter ratio imaging system, is presented. Computer simulations based on Mie scatter theory are used to determine the optimal angles for imaging. A detailed account of the early systems is presented to explain the motivations for the system design, especially polarization, wavelength and light path. Mitochondrial sized latex particles are used to determine the system response to changes in scattering particle size and concentration. The dual-angle scatter ratio imaging system is used to distinguish between osmotic and excitotoxic models of stroke injury. Such distinction cannot be achieved using the current techniques to study cellular swelling in hippocampal slices. The change in the scatter ratio is then shown to correlate to mitochondrial swelling, as observed with electron microscopy. The system is finally used to study mitochondrial and cellular swelling. Evidence of the susceptibility of certain hippocampal regions, CA1 and the dentate gyrus, to exhibit mitochondrial swelling as the result of oxygen and glucose deprivation is presented. In addition, for the first time, the time course of mitochondrial swelling is seen. Finally, experiments with scatter imaging and measurement of nitric oxide with carbon fiber electrodes demonstrate a clear link between nitric oxide and cellular swelling. A potential mechanism of the action of nitric oxide is evaluated. Nitric oxide appears to act to cause cellular swelling without the release of glutamate. The use of targeted nitric oxide inhibitors may be useful for the reduction of edema.

  20. Investigation of superelastic electron scattering by laser-excited Ba - Experimental procedures and results

    NASA Technical Reports Server (NTRS)

    Register, D. F.; Trajmar, S.; Fineman, M. A.; Poe, R. T.; Csanak, G.; Jensen, S. W.

    1983-01-01

    Differential (in angle) electron scattering experiments on laser-excited Ba-138 1P were carried out at 30- and 100-eV impact energies. The laser light was linearly polarized and located in the scattering plane. The superelastic scattering signal was measured as a function of polarization direction of the laser light with respect to the scattering plane. It was found at low electron scattering angles that the superelastic scattering signal was asymmetric to reflection of the polarization vector with respect to the scattering plane. This is in contradiction with theoretical predictions. An attempt was made to pinpoint the reason for this observation, and a detailed investigation of the influence of experimental conditions on the superelastic scattering was undertaken. No explanation for the asymmetry has as yet been found.

  1. [Effects of the first premolar extraction on the third molar angulation].

    PubMed

    He, Yu-hong; Duan, Yin-zhong; Pan, Ji-jun; Xi, Lan-lan

    2008-08-01

    To analyze the effects about inclinations of the second and the third molars in patients treated with or without premolar extractions. Fifty-six adolescents were chosen and divided into the first premolar extraction and non-extraction groups, 30 and 26 patients respectively. The pre-treatment and post-treatment panoramic radiographs were made. Angles between long axis of the third molar and the occlusal plane (the second molar alike), and long axis of the second and the third molar were measured and evaluated. The maxillary and mandibular third molar angulations were all improved after treatment in two groups. Compared with non-extraction group, the average changes of angle between long axis of the third molar and the occlusal plane increased significantly in maxilla and mandible (P < 0.05). Average changes of angles between long axis of the second and the third molar decreased and had statistically significant difference (P < 0.05). The change of angle between long axis of mandibular second molar and the occlusal plane had statistically significant difference (P < 0.05), but there was no statistically significant difference in maxillary second molar (P > 0.05). The first premolar extraction in orthodontic treatment could improve the third molar angulations and it would promote the eruption of the third molar.

  2. Anatomical planes: are we teaching accurate surface anatomy?

    PubMed

    Mirjalili, S Ali; McFadden, Sarah L; Buckenham, Tim; Wilson, Ben; Stringer, Mark D

    2012-10-01

    Anatomical planes used in clinical practice and teaching anatomy are largely derived from cadaver studies. Numerous inconsistencies in clinically important surface markings exist between and within anatomical reference texts. The aim of this study was to reassess the accuracy of common anatomical planes in vivo using computed tomographic (CT) imaging. CT scans of the trunk in supine adults at end tidal inspiration were analyzed by dual consensus reporting to determine the anatomy of five anatomical planes: sternal angle, transpyloric, subcostal, supracristal, and the plane of the pubic crest. Patients with kyphosis, scoliosis, or abnormal lordosis, distorting space-occupying lesions, or visceromegaly were excluded. Among 153 thoracic CT scans (mean age 63 years, 53% female), the sternal angle was most common at T4 (females) or T4/5 (males) vertebral level, and the tracheal bifurcation, aortic arch, and pulmonary trunk were most often below this plane. In 108 abdominal CT scans (mean age 60 years, 59% female), the subcostal and supracristal planes were most often at L2 (58%) and L4 (69%), respectively. In 52 thoracoabdominal CT scans (mean age 61 years, 56% female), the transpyloric plane was between lower L1 and upper L2 (75%); in this plane were the superior mesenteric artery (56%), formation of the portal vein (53%), tip of the ninth rib (60%), and the left renal hilum (54%), but the right renal hilum and gallbladder fundus were more often below. The surface anatomy of anatomical planes needs revising in the light of results from living subjects using modern imaging techniques. Copyright © 2012 Wiley Periodicals, Inc.

  3. Precession of a Spinning Ball Rolling down an Inclined Plane

    ERIC Educational Resources Information Center

    Cross, Rod

    2015-01-01

    A routine problem in an introductory physics course considers a rectangular block at rest on a plane inclined at angle a to the horizontal. In order for the block not to slide down the incline, the coefficient of sliding friction, µ, must be at least tan a. The situation is similar for the case of a ball rolling down an inclined plane. In order…

  4. 76 FR 23255 - Federal Motor Vehicle Safety Standards; Lamps, Reflective Devices, and Associated Equipment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-26

    ... plate holders so that the plane surface of a license plate in the holder would be within 15[deg] of perpendicular to the plane surface on which the vehicle stands. Paragraph S5.1.1 of the pre-reorganized version...). Among other requirements, SAE Standard J587 states in paragraph 6.1 that ``the angle between the plane...

  5. An inclined plane system with microcontroller to determine limb motor function of laboratory animals.

    PubMed

    Chang, Ming-Wen; Young, Ming-Shing; Lin, Mao-Tsun

    2008-02-15

    This study describes a high-accuracy inclined plane test system for quantitative measurement of the limb motor function of laboratory rats. The system is built around a microcontroller and uses a stepping motor to drive a ball screw, which changes the angle of the inclined plane. Any of the seven inclination speeds can be selected by the user. Two infrared (IR) LED/detector pairs function as interrupt sensors for objective determination of the moment that the rat loses its grip on the textured flooring of the starting area and slips down the plane. Inclination angle at the moment of IR interrupt (i.e. rat slip) is recorded. A liquid crystal display module shows the inclination speed and the inclination angle. The system can function as a stand alone device but a RS232 port allows connection to a personal computer (PC), so data can be sent directly to hard disk for storage and analysis. Experiments can be controlled by a local keypad or by the connected PC. Advantages of the presented system include easy operation, high accuracy, non-dependence on human observation for determination of slip angle, stand-alone capability, low cost and easy modification of the controlling software for different types of experiments. A fully functional prototype of the system is described. The prototype was used experimentally by a hospital group testing traumatic brain injury experiments, and some of their results are presented for system verification. It is found that the system is stable, accurate and easily used by investigators.

  6. Identifying changes in gait waveforms following a strengthening intervention for women with knee osteoarthritis using principal components analysis.

    PubMed

    Brenneman, Elora C; Maly, Monica R

    2018-01-01

    Lower limb strengthening exercise is pivotal for the management of symptoms related to knee osteoarthritis (OA). Though improvement in clinical symptoms is well documented, concurrent changes in gait biomechanics are ill-defined. This may occur because discrete analyses miss changes following an intervention, analyses limited to the knee undermine potential mechanical trade-offs at other joints, or strengthening interventions not been designed based on biomechanical principles. The purpose of this study was to characterize differences in entire gait waveforms for sagittal plane ankle, knee, and hip angles and external moments; the knee adduction moment; and frontal plane hip angle and moment following 12-weeks of a previously designed novel lower limb strengthening program. Forty women with knee OA completed two laboratory visits: one at baseline and one immediately following intervention (follow-up). Self-report measures, strength, and gait analyses were completed at each visit. Principal components analyses were completed for sagittal angles and external moments at the ankle, knee, and hip joints, as well as frontal plane angle and moment for the hip. Participants improved self-report and strength (p≤0.004). Two significant, yet subtle differences in principal components were identified between baseline and follow-up waveforms (p<0.05) pertaining to the knee and hip sagittal external moments. The subtle changes in concert with the lack of differences in other joints and planes suggest the lower limb strengthening program does not translate to changes in the gait waveform. It is likely this program is improving symptoms without worsening mechanics. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. The Effect of Sliding Humeral Osteotomy (SHO) on Frontal Plane Thoracic Limb Alignment: An Ex Vivo Canine Cadaveric Study.

    PubMed

    Breiteneicher, Adam H; Norby, Bo; Schulz, Kurt S; Kerwin, Sharon C; Hulse, Don A; Fox, Derek B; Saunders, W Brian

    2016-11-01

    To determine the effect of sliding humeral osteotomy (SHO) on frontal plane thoracic limb alignment in standing and recumbent limb positions. Canine cadaveric study. Canine thoracic limbs (n=15 limb pairs). Limbs acquired from healthy Labrador Retrievers euthanatized for reasons unrelated to this study were mounted in a limb press and aligned in a standing position followed by axial loading at 30% body weight. Frontal plane radiography was performed in standing and recumbent positions pre- and post-SHO. In the standing position, lateralization of the foot was measured pre- and post-SHO using a textured grid secured to the limb press base plate. Twelve thoracic limb alignment values (mean ± SD and 95% CI) were determined using the center of rotation of angulation (CORA) method were compared using linear mixed models to determine if significant differences existed between limb alignment values pre- or post-SHO, controlling for dog, limb, and limb position. Six of 12 standing or recumbent alignment values were significantly different pre- and post-SHO. SHO resulted in decreased mechanical lateral distal humeral angle and movement of the mechanical humeral radio-ulnar angle, radio-ulnar metacarpal angle, thoracic humeral angle, and elbow mechanical axis deviation toward coaxial limb alignment. In the standing position, the foot underwent significant lateralization post-SHO. SHO resulted in significant alteration in frontal plane thoracic limb alignment. Additional studies are necessary to determine if the changes reported using our ex vivo model occur following SHO in vivo. © Copyright 2016 by The American College of Veterinary Surgeons.

  8. Spread-Spectrum Beamforming and Clutter Filtering for Plane-Wave Color Doppler Imaging.

    PubMed

    Mansour, Omar; Poepping, Tamie L; Lacefield, James C

    2016-07-21

    Plane-wave imaging is desirable for its ability to achieve high frame rates, allowing the capture of fast dynamic events and continuous Doppler data. In most implementations of plane-wave imaging, multiple low-resolution images from different plane wave tilt angles are compounded to form a single high-resolution image, thereby reducing the frame rate. Compounding improves the lateral beam profile in the high-resolution image, but it also acts as a low-pass filter in slow time that causes attenuation and aliasing of signals with high Doppler shifts. This paper introduces a spread-spectrum color Doppler imaging method that produces high-resolution images without the use of compounding, thereby eliminating the tradeoff between beam quality, maximum unaliased Doppler frequency, and frame rate. The method uses a long, random sequence of transmit angles rather than a linear sweep of plane wave directions. The random angle sequence randomizes the phase of off-focus (clutter) signals, thereby spreading the clutter power in the Doppler spectrum, while keeping the spectrum of the in-focus signal intact. The ensemble of randomly tilted low-resolution frames also acts as the Doppler ensemble, so it can be much longer than a conventional linear sweep, thereby improving beam formation while also making the slow-time Doppler sampling frequency equal to the pulse repetition frequency. Experiments performed using a carotid artery phantom with constant flow demonstrate that the spread-spectrum method more accurately measures the parabolic flow profile of the vessel and outperforms conventional plane-wave Doppler in both contrast resolution and estimation of high flow velocities. The spread-spectrum method is expected to be valuable for Doppler applications that require measurement of high velocities at high frame rates.

  9. Orbital Tori Construction Using Trajectory Following Spectral Methods

    DTIC Science & Technology

    2010-09-01

    a Walker delta pattern scheme of 18/6/2. Explicitly, this means the 18 satellites were equally spaced in six planes , each inclined at 55 degrees, with...a relative phasing angle parameter of 2 [65]. The planes ’ inclinations were reduced from the original specification of 63 degrees to 55 degrees due...navigation performance specification for the SPS was ≤ 100 meters 8 in the horizontal plane , 95 percent of the time and ≤ 156 meters in the vertical plane

  10. The influence of early or delayed provision of ankle-foot orthoses on pelvis, hip and knee kinematics in patients with sub-acute stroke: A randomized controlled trial.

    PubMed

    Nikamp, Corien D M; van der Palen, Job; Hermens, Hermie J; Rietman, Johan S; Buurke, Jaap H

    2018-06-01

    Compensatory pelvis, hip- and knee movements are reported after stroke to overcome insufficient foot-clearance. Ankle-foot orthoses (AFOs) are often used to improve foot-clearance, but the optimal timing of AFO-provision post-stroke is unknown. Early AFO-provision to prevent foot-drop might decrease the development of compensatory movements, but it is unknown whether timing of AFO-provision affects post-stroke kinematics. 1) To compare the effect of AFO-provision at two different points in time (early versus delayed) on frontal pelvis and hip, and sagittal hip and knee kinematics in patients with sub-acute stroke. Effects were assessed after 26 weeks; 2) To study whether possible changes in kinematics or walking speed during the 26-weeks follow-up period differed between both groups. An explorative randomized controlled trial was performed, including unilateral hemiparetic patients maximal six weeks post-stroke with indication for AFO-use. Subjects were randomly assigned to AFO-provision early (at inclusion) or delayed (eight weeks later). 3D gait-analysis with and without AFO was performed in randomized order. Measurements were performed in study-week 1, 9, 17 and 26. Twenty-six subjects (15 early, 11 delayed) were analyzed. After 26 weeks, no differences in kinematics were found between both groups for any of the joint angles, both for the without and with AFO-condition. Changes in kinematics during the 26-weeks follow-up period did not differ between both groups for any of the joint angles during walking without AFO. Significant differences in changes in walking speed during the 26-weeks follow-up were found (p = 0.034), corresponding to the first eight weeks after AFO-provision. Results indicate that early or delayed AFO-use post-stroke does not influence pelvis, hip and knee movements after 26 weeks, despite that AFO-use properly corrected drop-foot. AFOs should be provided to improve drop-foot post-stroke, but not with the intention to influence development of compensatory patterns around pelvis and hip. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. The relationship between forward head posture and temporomandibular disorders.

    PubMed

    Lee, W Y; Okeson, J P; Lindroth, J

    1995-01-01

    This study investigated the relationship between forward head posture and temporomandibular disorder symptoms. Thirty-three temporomandibular disorder patients with predominant complaints of masticatory muscle pain were compared with an age- and gender-matched control group. Head position was measured from photographs taken with a plumb line drawn from the ceiling to the lateral malleolus of the ankle and with a horizontal plane that was perpendicular to the plumb line and that passed through the spinous process of the seventh cervical vertebra. The distances from the plumb line to the ear, to the seventh vertebra, and to the shoulder were measured. Two angles were also measured: (1) ear-seventh cervical vertebra-horizontal plane and (2) eye-ear-seventh cervical vertebra. The only measurement that revealed a statistically significant difference was angle ear-seventh cervical vertebra-horizontal plane. This angle was smaller in the patients with temporomandibular disorders than in the control subjects. In other words, when evaluating the ear position with respect to the seventh cervical vertebra, the head was positioned more forward in the group with temporomandibular disorders than in the control group (P < .05).

  12. A comparison of economy and sagittal plane trunk movements among back-, back/front- and head-loading.

    PubMed

    Hudson, Sean; Cooke, Carlton; Davies, Simeon; West, Sacha; Gamieldien, Raeeq; Low, Chris; Lloyd, Ray

    2018-05-14

    It has been suggested that freedom of movement in the trunk could influence load carriage economy. This study aimed to compare the economy and sagittal plane trunk movements associated with three load carriage methods that constrain posture differently. Eighteen females walked at 3 km.h -1 with loads of 0, 3, 6, 9, 12, 15 and 20 kg carried on the back, back/front and head. Load carriage economy was assessed using the Extra Load Index (ELI). Change in sagittal plane trunk forward lean and trunk angle excursion from unloaded to loaded walking were assessed. Results show no difference in economy between methods (p = 0.483), despite differences in the change in trunk forward lean (p = 0.001) and trunk angle excursion (p = 0.021) from unloaded to loaded walking. We conclude that economy is not different among the three methods of load carriage, despite significant differences in sagittal plane trunk movements.

  13. Clinical measurement of the dart throwing motion of the wrist: variability, accuracy and correction.

    PubMed

    Vardakastani, Vasiliki; Bell, Hannah; Mee, Sarah; Brigstocke, Gavin; Kedgley, Angela E

    2018-01-01

    Despite being functionally important, the dart throwing motion is difficult to assess accurately through goniometry. The objectives of this study were to describe a method for reliably quantifying the dart throwing motion using goniometric measurements within a healthy population. Wrist kinematics of 24 healthy participants were assessed using goniometry and optical motion tracking. Three wrist angles were measured at the starting and ending points of the motion: flexion-extension, radial-ulnar deviation and dart throwing motion angle. The orientation of the dart throwing motion plane relative to the flexion-extension axis ranged between 28° and 57° among the tested population. Plane orientations derived from optical motion capture differed from those calculated through goniometry by 25°. An equation to correct the estimation of the plane from goniometry measurements was derived. This was applied and differences in the orientation of the plane were reduced to non-significant levels, enabling the dart throwing motion to be measured using goniometry alone.

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

    Reimberg, Paulo; Bernardeau, Francis; Pitrou, Cyril, E-mail: paulo.flose-reimberg@cea.fr, E-mail: francis.bernardeau@cea.fr, E-mail: pitrou@iap.fr

    Redshift-space distortions are generally considered in the plane parallel limit, where the angular separation between the two sources can be neglected. Given that galaxy catalogues now cover large fractions of the sky, it becomes necessary to consider them in a formalism which takes into account the wide angle separations. In this article we derive an operational formula for the matter correlators in the Newtonian limit to be used in actual data sets. In order to describe the geometrical nature of the wide angle RSD effect on Fourier space, we extend the formalism developed in configuration space to Fourier space withoutmore » relying on a plane-parallel approximation, but under the extra assumption of no bias evolution. We then recover the plane-parallel limit not only in configuration space where the geometry is simpler, but also in Fourier space, and we exhibit the first corrections that should be included in large surveys as a perturbative expansion over the plane-parallel results. We finally compare our results to existing literature, and show explicitly how they are related.« less

  15. Handbook of Inviscid Sphere-Cone Flow Fields and Pressure Distributions. Volume 1

    DTIC Science & Technology

    1975-12-01

    8.00 ANGLE OF ATTACK = 1.00 P / P FREE-STREAM AT PLANE ANGLES L/RN 0. 30. 60. 90. 120. iso . 180. S/RN 62.835 34.625 33.936 31.809 27.874 23.163 19.897...1.954 1 922 11273 6.972 3.241 3069 2663 2 2.20 27003 1.876 1.843 12*372 12817 3.228 3.046 2.619 2211 1.939 1.811 1.778 13.453 3*576 3.23t -4-,-G40 59...AT PLANE ANGLES -L/RN 0. 30. 60. 90. 1206 150. ISO * S/RN .728 55.729 51.603 41.628 30.695 22.303 17.474 15.941 1.296 o874 52.472 48.397 38.674 28.299

  16. Erratum: ``CO Line Width Differences in Early Universe Molecular Emission-Line Galaxies: Submillimeter Galaxies versus QSO Hosts'' (AJ, 131, 2763 [2006])

    NASA Astrophysics Data System (ADS)

    Carilli, C. L.; Wang, Ran

    2006-11-01

    It has been pointed out to us that in three dimensions the mean angle of randomly oriented disks with respect to the sky plane is <θ>=30deg, and not the 45° assumed in the original paper. This lower angle for the (assumed) random distribution of submillimeter galaxies, coupled with the factor of 2.3 lower mean CO line width for high-z, far-IR-luminous QSO host galaxies relative to the submillimeter galaxies, implies a mean angle with respect to the sky plane for the QSO host galaxies of <θ>QSO=13deg, as opposed to the 18° quoted in the original paper. We thank Pat Hall for bringing this to our attention.

  17. Pusher syndrome--a frequent but little-known disturbance of body orientation perception.

    PubMed

    Karnath, Hans-Otto

    2007-04-01

    Disturbances of body orientation perception after brain lesions may specifically relate to only one dimension of space. Stroke patients with "pusher syndrome" suffer from a severe misperception of their body's orientation in the coronal (roll) plane. They experience their body as oriented 'upright' when it is in fact markedly tilted to one side. The patients use the unaffected arm or leg to actively push away from the un-paralyzed side and resist any attempt to passively correct their tilted body posture. Although pusher patients are unable to correctly determine when their own body is oriented in an upright, vertical position, they seem to have no significant difficulty in determining the orientation of the surrounding visual world in relation to their own body. Pusher syndrome is a distinctive clinical disorder occurring characteristically after unilateral left or right brain lesions in the posterior thalamus and -less frequently- in the insula and postcentral gyrus. These structures thus seem to constitute crucial neural substrates controlling human (upright) body orientation in the coronal (roll) plane. A further disturbance of body orientation that predominantly affects a single dimension of space, namely the transverse (yaw) plane, is observed in stroke patients with spatial neglect. Apparently, our brain has evolved separate neural subsystems for perceiving and controlling body orientation in different dimensions of space.

  18. Relationship between vertical facial patterns and dental arch form in class II malocclusion.

    PubMed

    Grippaudo, Cristina; Oliva, Bruno; Greco, Anna Lucia; Sferra, Simone; Deli, Roberto

    2013-11-07

    The purpose of this study is to evaluate the relationship between dental arch form and the vertical facial pattern determined by the angle between the mandibular plane and the anterior cranial base (Sella-nasion/mandibular plane angle (SN-MP)) in skeletal class II untreated patients. A sample of 73 Caucasians patients with untreated skeletal class II in permanent dentition was divided into three groups according to the values of the angle SN-MP. An evaluation of the arch form was performed by angular and linear relation values on each patient. Regression analysis was used to determine the statistical significance of the relationships between SN-MP angle and dental arch form. The differences among the three groups were analyzed for significance using a variance analysis. A decrease of the upper arch transversal diameters in high SN-MP angle patients and an increase in low angle SN-MP ones (P<0.05) were shown. Result analysis showed a change in upper arch shape, with a smaller intercanine width in patients with high SN-MP angle and a greater one in low angle patients. As SN-MP angle increased, the upper arch form tended to be narrower. No statistically significant difference in mandibular arch form among the three groups was found, except the angle value related to incisors position. The results showed the association between the upper dental arch form and the vertical facial pattern. On the contrary, the lower arch form was not related to the mandibular divergence.

  19. Video raster stereography back shape reconstruction: a reliability study for sagittal, frontal, and transversal plane parameters.

    PubMed

    Schroeder, J; Reer, R; Braumann, K M

    2015-02-01

    As reliability of raster stereography was proved only for sagittal plane parameters with repeated measures on the same day, the present study was aiming at investigating variability and reliability of back shape reconstruction for all dimensions (sagittal, frontal, transversal) and for different intervals. For a sample of 20 healthy volunteers, intra-individual variability (SEM and CV%) and reliability (ICC ± 95% CI) were proved for sagittal (thoracic kyphosis, lumbar lordosis, pelvis tilt angle, and trunk inclination), frontal (pelvis torsion, pelvis and trunk imbalance, vertebral side deviation, and scoliosis angle), transversal (vertebral rotation), and functional (hyperextension) spine shape reconstruction parameters for different test-retest intervals (on the same day, between-day, between-week) by means of video raster stereography. Reliability was high for the sagittal plane (pelvis tilt, kyphosis and lordosis angle, and trunk inclination: ICC > 0.90), and good to high for lumbar mobility (0.86 < ICC < 0.97). Apart from sagittal plane spinal alignment, there was a lack of certainty for a high reproducibility indicated by wider ICC confidence intervals. So, reliability was fair to high for vertebral side deviation and the scoliosis angle (0.71 < ICC < 0.95), and poor to good for vertebral rotation values as well as for frontal plane upper body and pelvis position parameters (0.65 < ICC < 0.92). Coefficients for the between-day and between-week interval were a little lower than for repeated measures on the same day. Variability (SEM) was less than 1.5° or 1.5 mm, except for trunk inclination. Relative variability (CV) was greater in global trunk position and pelvis parameters (35-98%) than in scoliosis (14-20%) or sagittal sway parameters (4-8 %). Although we found a lower reproducibility for the frontal plane, raster stereography is considered to be a reliable method for the non-invasive, three-dimensional assessment of spinal alignment in normal non-scoliotic individuals in the sagittal plane and partly for scoliosis parameters, which fulfils scientific as well as practical recommendations for spine shape screening and monitoring, but cross-sectional or follow-up effect analyses should take into account the degree of reliability differing in various spine shape parameters. Further investigations should be conducted to analyse reliability in scoliosis patients with differing spinal deformities.

  20. Angle measures, general rotations, and roulettes in normed planes

    NASA Astrophysics Data System (ADS)

    Balestro, Vitor; Horváth, Ákos G.; Martini, Horst

    2017-12-01

    In this paper a special group of bijective maps of a normed plane (or, more generally, even of a plane with a suitable Jordan curve as unit circle) is introduced which we call the group of general rotations of that plane. It contains the isometry group as a subgroup. The concept of general rotations leads to the notion of flexible motions of the plane, and to the concept of Minkowskian roulettes. As a nice consequence of this new approach to motions the validity of strong analogues to the Euler-Savary equations for Minkowskian roulettes is proved.

  1. Single beam write and/or replay of spatial heterodyne holograms

    DOEpatents

    Thomas, Clarence E.; Hanson, Gregory R.

    2007-11-20

    A method of writing a spatially heterodyne hologram having spatially heterodyne fringes includes: passing a single write beam through a spatial light modulator that digitally modulates said single write beam; and focusing the single write beam at a focal plane of a lens to impose a holographic diffraction grating pattern on the photorefractive crystal, the holographic diffraction grating pattern including the spatially heterodyne hologram having spatially heterodyne fringes, wherein only said single write beam is incident on said photorefractive crystal without a reference beam. A method of replaying a spatially heterodyne hologram having spatially heterodyne fringes at a replay angle includes: illuminating a photorefractive crystal having a holographic diffraction grating with a beam from a laser at an illumination angle, the holographic diffraction grating pattern including the spatially heterodyne hologram having spatially heterodyne fringes, wherein a difference between said illumination angle and said replay angle defines a diffraction angle .alpha. that is a function of a plane wave mathematically added to original object wave phase and amplitude data of said spatially heterodyne hologram having spatially heterodyne fringes.

  2. Performance of an Achromatic Focal Plane Mask for Exoplanet Imaging Coronagraphy

    NASA Technical Reports Server (NTRS)

    Newman, Kevin; Belikov, Ruslan; Pluzhnik, Eugene; Balasubramanian, Kunjithapatham; Wilson, Dan

    2014-01-01

    Coronagraph technology combined with wavefront control is close to achieving the contrast and inner working angle requirements in the lab necessary to observe the faint signal of an Earth-like exoplanet in monochromatic light. An important remaining technological challenge is to achieve high contrast in broadband light. Coronagraph bandwidth is largely limited by chromaticity of the focal plane mask, which is responsible for blocking the stellar PSF. The size of a stellar PSF scales linearly with wavelength; ideally, the size of the focal plane mask would also scale with wavelength. A conventional hard-edge focal plane mask has a fixed size, normally sized for the longest wavelength in the observational band to avoid starlight leakage. The conventional mask is oversized for shorter wavelengths and blocks useful discovery space. Recently we presented a solution to the size chromaticity challenge with a focal plane mask designed to scale its effective size with wavelength. In this paper, we analyze performance of the achromatic size-scaling focal plane mask within a Phase Induced Amplitude Apodization (PIAA) coronagraph. We present results from wavefront control around the achromatic focal plane mask, and demonstrate the size-scaling effect of the mask with wavelength. The edge of the dark zone, and therefore the inner working angle of the coronagraph, scale with wavelength. The achromatic mask enables operation in a wider band of wavelengths compared with a conventional hard-edge occulter.

  3. Super-global distortion correction for a rotational C-arm x-ray image intensifier.

    PubMed

    Liu, R R; Rudin, S; Bednarek, D R

    1999-09-01

    Image intensifier (II) distortion changes as a function of C-arm rotation angle because of changes in the orientation of the II with the earth's or other stray magnetic fields. For cone-beam computed tomography (CT), distortion correction for all angles is essential. The new super-global distortion correction consists of a model to continuously correct II distortion not only at each location in the image but for every rotational angle of the C arm. Calibration bead images were acquired with a standard C arm in 9 in. II mode. The super-global (SG) model is obtained from the single-plane global correction of the selected calibration images with given sampling angle interval. The fifth-order single-plane global corrections yielded a residual rms error of 0.20 pixels, while the SG model yielded a rms error of 0.21 pixels, a negligibly small difference. We evaluated the accuracy dependence of the SG model on various factors, such as the single-plane global fitting order, SG order, and angular sampling interval. We found that a good SG model can be obtained using a sixth-order SG polynomial fit based on the fifth-order single-plane global correction, and that a 10 degrees sampling interval was sufficient. Thus, the SG model saves processing resources and storage space. The residual errors from the mechanical errors of the x-ray system were also investigated, and found comparable with the SG residual error. Additionally, a single-plane global correction was done in the cylindrical coordinate system, and physical information about pincushion distortion and S distortion were observed and analyzed; however, this method is not recommended due to a lack of calculational efficiency. In conclusion, the SG model provides an accurate, fast, and simple correction for rotational C-arm images, which may be used for cone-beam CT.

  4. Robot cable-compliant devices

    NASA Technical Reports Server (NTRS)

    Kerley, James J., Jr. (Inventor)

    1990-01-01

    A cable compliant robotic joint includes two U configuration cross section brackets with their U cross sections lying in different planes, one of their brackets being connected to a robot arm and the other to a tool. Additional angle brackets are displaced from the other brackets at corners of the robotic joint. All the brackets are connected by cable segments which lie in one or more planes which are perpendicular to the direction of tool travel as it approaches a work object. The compliance of the joint is determined by the cable segment characteristics, such as their length, material, angle, stranding, pretwisting, and prestressing.

  5. 4-(4-Methoxy­phen­yl)-1-phenyl­pyridine-2,6(1H,3H)-dione

    PubMed Central

    Das, Ushati; Chheda, Shardul B.; Pednekar, Suhas R.; Karambelkar, Narendra P.; Guru Row, T. N.

    2009-01-01

    In the title compound, C18H15NO3, the pyridine-2,6-dione ring adopts an envelope conformation. The phenyl ring lies approximately perpendicular to the mean plane of the pyridine-2,6-dione ring [dihedral angle = 81.5 (1)°], while the methoxy­phenyl ring is tilted to the same plane by a dihedral angle of 34.8 (1)°. Inter­molecular C—H⋯O inter­actions link the mol­ecules into chains along [100]. PMID:21583176

  6. Proteus-MOC: A 3D deterministic solver incorporating 2D method of characteristics

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

    Marin-Lafleche, A.; Smith, M. A.; Lee, C.

    2013-07-01

    A new transport solution methodology was developed by combining the two-dimensional method of characteristics with the discontinuous Galerkin method for the treatment of the axial variable. The method, which can be applied to arbitrary extruded geometries, was implemented in PROTEUS-MOC and includes parallelization in group, angle, plane, and space using a top level GMRES linear algebra solver. Verification tests were performed to show accuracy and stability of the method with the increased number of angular directions and mesh elements. Good scalability with parallelism in angle and axial planes is displayed. (authors)

  7. Electro-optical detector for use in a wide mass range mass spectrometer

    NASA Technical Reports Server (NTRS)

    Giffin, Charles E. (Inventor)

    1976-01-01

    An electro-optical detector is disclosed for use in a wide mass range mass spectrometer (MS), in the latter the focal plane is at or very near the exit end of the magnetic analyzer, so that a strong magnetic field of the order of 1000G or more is present at the focal plane location. The novel detector includes a microchannel electron multiplier array (MCA) which is positioned at the focal plane to convert ion beams which are focused by the MS at the focal plane into corresponding electron beams which are then accelerated to form visual images on a conductive phosphored surface. These visual images are then converted into images on the target of a vidicon camera or the like for electronic processing. Due to the strong magnetic field at the focal plane, in one embodiment of the invention, the MCA with front and back parallel ends is placed so that its front end forms an angle of not less than several degrees, preferably on the order of 10.degree.-20.degree., with respect to the focal plane, with the center line of the front end preferably located in the focal plane. In another embodiment the MCA is wedge-shaped, with its back end at an angle of about 10.degree.-20.degree. with respect to the front end. In this embodiment the MCA is placed so that its front end is located at the focal plane.

  8. Primary Motor Cortex in Stroke A Functional MRI-Guided Proton MR Spectroscopic Study

    PubMed Central

    Cirstea, Carmen M.; Brooks, William M.; Craciunas, Sorin C.; Popescu, Elena A.; Choi, In-Young; Lee, Phil; Bani-Ahmed, Ali; Yeh, Hung-Wen; Savage, Cary R.; Cohen, Leonardo G.; Nudo, Randolph J.

    2012-01-01

    Background and Purpose Our goal was to investigate whether certain metabolites, specific to neurons, glial cells, or the neuronal-glial neurotransmission system, in primary motor cortices (M1), are altered and correlated with clinical motor severity in chronic stroke. Methods Fourteen survivors of a single ischemic stroke located outside the M1 and 14 age-matched healthy control subjects were included. At >6 months after stroke, N-acetylaspartate, myo-inositol, and glutamate/glutamine were measured using proton magnetic resonance spectroscopic imaging (in-plane resolution=5×5 mm2) in radiologically normal-appearing gray matter of the hand representation area, identified by functional MRI, in each M1. Metabolite concentrations and analyses of metabolite correlations within M1 were determined. Relationships between metabolite concentrations and arm motor impairment were also evaluated. Results The stroke survivors showed lower N-acetylaspartate and higher myo-inositol across ipsilesional and contral-esional M1 compared with control subjects. Significant correlations between N-acetylaspartate and glutamate/glutamine were found in either M1. Ipsilesional N-acetylaspartate and glutamate/glutamine were positively correlated with arm motor impairment and contralesional N-acetylaspartate with time after stroke. Conclusions Our preliminary data demonstrated significant alterations of neuronal-glial interactions in spared M1 with the ipsilesional alterations related to stroke severity and contralesional alterations to stroke duration. Thus, MR spectroscopy might be a sensitive method to quantify relevant metabolite changes after stroke and consequently increase our knowledge of the factors leading from these changes in spared motor cortex to motor impairment after stroke. PMID:21330627

  9. FIBRE AND INTEGRATED OPTICS. OPTICAL PROCESSING OF INFORMATION: Intrafibre rotation of the plane of polarisation

    NASA Astrophysics Data System (ADS)

    Zel'dovich, Boris Ya; Kundikova, N. D.

    1995-02-01

    Rotation of the plane of polarisation during propagation of sagittal rays in a rectilinear multimode fibre was observed experimentally. The angle of rotation was in good agreement with the results predicted on the basis of the Rytov—Vladimirskii—Berry theory.

  10. Correlation between Topographic Parameters Obtained by Back Surface Topography Based on Structured Light and Radiographic Variables in the Assessment of Back Morphology in Young Patients with Idiopathic Scoliosis.

    PubMed

    Pino-Almero, Laura; Mínguez-Rey, María Fe; Cibrián-Ortiz de Anda, Rosa María; Salvador-Palmer, María Rosario; Sentamans-Segarra, Salvador

    2017-04-01

    Optical cross-sectional study. To study the correlation between asymmetry of the back (measured by means of surface topography) and deformity of the spine (quantified by the Cobb angle). The Cobb angle is considered the gold standard in diagnosis and follow-up of scoliosis but does not correctly characterize the three-dimensional deformity of scoliosis. Furthermore, the exposure to ionizing radiation may cause harmful effects particularly during the growth stage, including breast cancer and other tumors. Patients aged 13.15±1.96 years (range, 7-17 years; n=88) with Cobb angle greater than 10° were evaluated with X-rays and our back surface topography method through three variables: axial plane (DHOPI), coronal plane (POTSI), and profile plane (PC). Pearson's correlation was applied to determine the correlation between topographic and radiographic variables. One-way analysis of variance and Bonferroni correction were used to compare groups with different grades of scoliosis. Significance was set at p <0.01 and, in some cases, at p <0.05. We detected a positive, statistically significant correlation between Cobb angle with DHOPI ( r =0.810) and POTSI ( r =0.629) and between PC variables with thoracic kyphosis angle ( r =0.453) and lordosis lumbar angle ( r =0.275). In addition, we found statistically significant differences for DHOPI and POTSI variables according to the grade of scoliosis. Although the back surface topography method cannot substitute for radiographs in the diagnosis of scoliosis, correlations between radiographic and topographic parameters suggest that it offers additional quantitative data that may complement radiologic study.

  11. Aerodynamic Measurements of a Variable-Speed Power-Turbine Blade Section in a Transonic Turbine Cascade

    NASA Technical Reports Server (NTRS)

    Flegel, Ashlie B.

    2014-01-01

    The purpose of this thesis is to document the impact of incidence angle and Reynolds number variations on the three-dimensional flow field and midspan loss and turning of a two-dimensional section of a variable-speed power-turbine (VSPT) rotor blade. Aerodynamic measurements were obtained in a transonic linear cascade at NASA Glenn Research Center in Cleveland, Ohio. Steady-state data were obtained for 10 incidence angles ranging from +15.8deg to -51.0deg. At each angle, data were acquired at five flow conditions with the exit Reynolds number (based on axial chord) varying over an order-of-magnitude from 2.12×105 to 2.12×106. Data were obtained at the design exit Mach number of 0.72 and at a reduced exit Mach number of 0.35 as required to achieve the lowest Reynolds number. Midspan tota lpressure and exit flow angle data were acquired using a five-hole pitch/yaw probe surveyed on a plane located 7.0 percent axial-chord downstream of the blade trailing edge plane. The survey spanned three blade passages. Additionally, three-dimensional half-span flow fields were examined with additional probe survey data acquired at 26 span locations for two key incidence angles of +5.8deg and -36.7deg. Survey data near the endwall were acquired with a three-hole boundary-layer probe. The data were integrated to determine average exit total-pressure and flow angle as functions of incidence and flow conditions. The data set also includes blade static pressures measured on four spanwise planes and endwall static pressures.

  12. Experimental Evaluation of the Effect of Angle-of-attack on the External Aerodynamics and Mass Capture of a Symmetric Three-engine Air-breathing Launch Vehicle Configuration at Supersonic Speeds

    NASA Technical Reports Server (NTRS)

    Kim, Hyun D.; Frate, Franco C.

    2001-01-01

    A subscale aerodynamic model of the GTX air-breathing launch vehicle was tested at NASA Glenn Research Center's 10- by 10-Foot Supersonic Wind Tunnel from Mach 2.0 to 3.5 at various angles-of-attack. The objective of the test was to investigate the effect of angle-of-attack on inlet mass capture, inlet diverter effectiveness, and the flowfield at the cowl lip plane. The flow-through inlets were tested with and without boundary-layer diverters. Quantitative measurements such as inlet mass flow rates and pitot-pressure distributions in the cowl lip plane are presented. At a 3deg angle-of-attack, the flow rates for the top and side inlets were within 8 percent of the zero angle-of-attack value, and little distortion was evident at the cowl lip plane. Surface oil flow patterns showing the shock/boundary-layer interaction caused by the inlet spikes are shown. In addition to inlet data, vehicle forebody static pressure distributions, boundary-layer profiles, and temperature-sensitive paint images to evaluate the boundary-layer transition are presented. Three-dimensional parabolized Navier-Stokes computational fluid dynamics calculations of the forebody flowfield are presented and show good agreement with the experimental static pressure distributions and boundary-layer profiles. With the boundary-layer diverters installed, no adverse aerodynamic phenomena were found that would prevent the inlets from operating at the required angles-of-attack. We recommend that phase 2 of the test program be initiated, where inlet contraction ratio and diverter geometry variations will be tested.

  13. Azimuthal-angle dependence of charged-pion-interferometry measurements with respect to second- and third-order event planes in Au+Au collisions at √[S(NN)]=200  GeV.

    PubMed

    Adare, A; Afanasiev, S; Aidala, C; Ajitanand, N N; Akiba, Y; Al-Bataineh, H; Alexander, J; Aoki, K; Aramaki, Y; Atomssa, E T; Averbeck, R; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Baksay, G; Baksay, L; Barish, K N; Bassalleck, B; Basye, A T; Bathe, S; Baublis, V; Baumann, C; Bazilevsky, A; Belikov, S; Belmont, R; Bennett, R; Berdnikov, A; Berdnikov, Y; Bickley, A A; Bok, J S; Boyle, K; Brooks, M L; Buesching, H; Bumazhnov, V; Bunce, G; Butsyk, S; Camacho, C M; Campbell, S; Chen, C-H; Chi, C Y; Chiu, M; Choi, I J; Choudhury, R K; Christiansen, P; Chujo, T; Chung, P; Chvala, O; Cianciolo, V; Citron, Z; Cole, B A; Connors, M; Constantin, P; Csanád, M; Csörgő, T; Dahms, T; Dairaku, S; Danchev, I; Das, K; Datta, A; David, G; Denisov, A; Deshpande, A; Desmond, E J; Dietzsch, O; Dion, A; Donadelli, M; Drapier, O; Drees, A; Drees, K A; Durham, J M; Durum, A; Dutta, D; Edwards, S; Efremenko, Y V; Ellinghaus, F; Engelmore, T; Enokizono, A; En'yo, H; Esumi, S; Fadem, B; Fields, D E; Finger, M; Finger, M; Fleuret, F; Fokin, S L; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fujiwara, K; Fukao, Y; Fusayasu, T; Garishvili, I; Glenn, A; Gong, H; Gonin, M; Goto, Y; Granier de Cassagnac, R; Grau, N; Greene, S V; Grosse Perdekamp, M; Gunji, T; Gustafsson, H-Å; Haggerty, J S; Hahn, K I; Hamagaki, H; Hamblen, J; Han, R; Hanks, J; Hartouni, E P; Haslum, E; Hayano, R; He, X; Heffner, M; Hemmick, T K; Hester, T; Hill, J C; Hohlmann, M; Holzmann, W; Homma, K; Hong, B; Horaguchi, T; Hornback, D; Huang, S; Ichihara, T; Ichimiya, R; Ide, J; Ikeda, Y; Imai, K; Inaba, M; Isenhower, D; Ishihara, M; Isobe, T; Issah, M; Isupov, A; Ivanischev, D; Jacak, B V; Jia, J; Jin, J; Johnson, B M; Joo, K S; Jouan, D; Jumper, D S; Kajihara, F; Kametani, S; Kamihara, N; Kamin, J; Kang, J H; Kapustinsky, J; Karatsu, K; Kawall, D; Kawashima, M; Kazantsev, A V; Kempel, T; Khanzadeev, A; Kijima, K M; Kim, B I; Kim, D H; Kim, D J; Kim, E; Kim, E-J; Kim, S H; Kim, Y-J; Kinney, E; Kiriluk, K; Kiss, A; Kistenev, E; Kochenda, L; Komkov, B; Konno, M; Koster, J; Kotchetkov, D; Kozlov, A; Král, A; Kravitz, A; Kunde, G J; Kurita, K; Kurosawa, M; Kwon, Y; Kyle, G S; Lacey, R; Lai, Y S; Lajoie, J G; Lebedev, A; Lee, D M; Lee, J; Lee, K; Lee, K B; Lee, K S; Leitch, M J; Leite, M A L; Leitner, E; Lenzi, B; Li, X; Liebing, P; Linden Levy, L A; Liška, T; Litvinenko, A; Liu, H; Liu, M X; Love, B; Luechtenborg, R; Lynch, D; Maguire, C F; Makdisi, Y I; Malakhov, A; Malik, M D; Manko, V I; Mannel, E; Mao, Y; Masui, H; Matathias, F; McCumber, M; McGaughey, P L; Means, N; Meredith, B; Miake, Y; Mignerey, A C; Mikeš, P; Miki, K; Milov, A; Mishra, M; Mitchell, J T; Mohanty, A K; Morino, Y; Morreale, A; Morrison, D P; Moukhanova, T V; Murata, J; Nagamiya, S; Nagle, J L; Naglis, M; Nagy, M I; Nakagawa, I; Nakamiya, Y; Nakamura, T; Nakano, K; Newby, J; Nguyen, M; Niida, T; Nouicer, R; Nyanin, A S; O'Brien, E; Oda, S X; Ogilvie, C A; Oka, M; Okada, K; Onuki, Y; Oskarsson, A; Ouchida, M; Ozawa, K; Pak, R; Pantuev, V; Papavassiliou, V; Park, I H; Park, J; Park, S K; Park, W J; Pate, S F; Pei, H; Peng, J-C; Pereira, H; Peresedov, V; Peressounko, D Yu; Pinkenburg, C; Pisani, R P; Proissl, M; Purschke, M L; Purwar, A K; Qu, H; Rak, J; Rakotozafindrabe, A; Ravinovich, I; Read, K F; Reygers, K; Riabov, V; Riabov, Y; Richardson, E; Roach, D; Roche, G; Rolnick, S D; Rosati, M; Rosen, C A; Rosendahl, S S E; Rosnet, P; Rukoyatkin, P; Ružička, P; Sahlmueller, B; Saito, N; Sakaguchi, T; Sakashita, K; Samsonov, V; Sano, S; Sato, T; Sawada, S; Sedgwick, K; Seele, J; Seidl, R; Semenov, A Yu; Seto, R; Sharma, D; Shein, I; Shibata, T-A; Shigaki, K; Shimomura, M; Shoji, K; Shukla, P; Sickles, A; Silva, C L; Silvermyr, D; Silvestre, C; Sim, K S; Singh, B K; Singh, C P; Singh, V; Slunečka, M; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Sparks, N A; Stankus, P W; Stenlund, E; Stoll, S P; Sugitate, T; Sukhanov, A; Sziklai, J; Takagui, E M; Taketani, A; Tanabe, R; Tanaka, Y; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tarján, P; Themann, H; Thomas, T L; Todoroki, T; Togawa, M; Toia, A; Tomášek, L; Torii, H; Towell, R S; Tserruya, I; Tsuchimoto, Y; Vale, C; Valle, H; van Hecke, H W; Vazquez-Zambrano, E; Veicht, A; Velkovska, J; Vértesi, R; Vinogradov, A A; Virius, M; Vrba, V; Vznuzdaev, E; Wang, X R; Watanabe, D; Watanabe, K; Watanabe, Y; Wei, F; Wei, R; Wessels, J; White, S N; Winter, D; Wood, J P; Woody, C L; Wright, R M; Wysocki, M; Xie, W; Yamaguchi, Y L; Yamaura, K; Yang, R; Yanovich, A; Ying, J; Yokkaichi, S; You, Z; Young, G R; Younus, I; Yushmanov, I E; Zajc, W A; Zhang, C; Zhou, S; Zolin, L

    2014-06-06

    Charged-pion-interferometry measurements were made with respect to the second- and third-order event plane for Au+Au collisions at sqrt[s_{NN}]=200  GeV. A strong azimuthal-angle dependence of the extracted Gaussian-source radii was observed with respect to both the second- and third-order event planes. The results for the second-order dependence indicate that the initial eccentricity is reduced during the medium evolution, which is consistent with previous results. In contrast, the results for the third-order dependence indicate that the initial triangular shape is significantly reduced and potentially reversed by the end of the medium evolution, and that the third-order oscillations are largely dominated by the dynamical effects from triangular flow.

  14. Modification of the sagittal split osteotomy of the mandibular ramus: mobilizing vertical osteotomy of the internal ramus segment.

    PubMed

    Ricard, Daniel; Ferri, Joël

    2009-08-01

    We describe a new surgical procedure to improve stability when counterclockwise rotation of the maxillomandibular complex and the occlusal plane is intended. This preliminary prospective study evaluated 10 patients (8 female patients and 2 male patients) who each underwent maxillomandibular surgical advancement with counterclockwise rotation of the occlusal plane. A mandibular counterclockwise rotation was done in all cases with bilateral ramus sagittal split osteotomy. After the split of the ramus had been completed, a vertical osteotomy was done distally to the second molar on the internal ramus segment. With the completion of this vertical osteotomy, the internal ramus segment became completely mobile. All osteotomies were stabilized with rigid internal fixation by use of plates with monocortical screws. Ten patients have been treated with the "mobilizing vertical osteotomy of the internal ramus segment." The mean reduction of the occlusal plane angle was 10.1 degrees , showing a substantial counterclockwise rotation of the maxillomandibular complex. All patients had significant improvement of their facial balance. After a 1-year follow-up period, all cases but 1 showed very good stability of their occlusion and occlusal plane angle. An 11.4% relapse of the forward movement of the mandible was noted. On the basis of this prospective study, we conclude that when performing a counterclockwise rotation of the maxillomandibular complex, the mobilizing vertical osteotomy of the internal ramus segment combined with the sagittal split osteotomy of the mandible potentially enhances the occlusal plane angle and occlusal stability after a 1-year period.

  15. The interface character distribution of cold-rolled and annealed duplex stainless steel

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

    Fang, Xiaoying, E-mail: fxy@sdut.edu.cn

    The interface character distributions (ICDs) of cold-rolled and annealed duplex stainless steel specimens, previously solid-solution-heated (SHT) at 1573 K and 1323 K, are investigated using electron backscatter diffraction (EBSD) and five-parameter analysis (FPA). For the δ-ferrite phase, high concentrations of low angle grain boundaries (LAGBs) are developed, and the boundary planes are predominantly oriented on (111). High angle grain boundaries (HAGBs) with misorientations ranging from 50{sup o} to 60° are mostly pure tilt boundaries, and the boundary planes are primarily located on (112). For the austenite phase, very high density of coherent twin boundaries are introduced, implying that the boundarymore » planes are exactly oriented on (111). The phase boundary character distribution (PBPD) appears to be connected with the K-S and N-W orientation relationships (ORs) terminating on (110) {sub F}‖(111) {sub A} and (110){sub F}‖(hkl){sub A}, respectively. - Highlights: •Five-parameter analysis was used to determine interface character distribution. •ICD results of statistical meaning were achieved. •Initial microstructure has a significant effect on ICD. •Low and high angle GBs in δ phase prefer in (111) and (112) planes, respectively. •K-S phase boundaries terminate on (110){sub F}‖(111){sub A} while N-W ones on (110){sub F}‖(hkl){sub A}.« less

  16. Comparing non-invasive scapular tracking methods across elevation angles, planes of elevation and humeral axial rotations.

    PubMed

    Grewal, T-J; Cudlip, A C; Dickerson, C R

    2017-12-01

    Altered scapular motions premeditate shoulder impingement and other musculoskeletal disorders. Divergent experimental conditions in previous research precludes rigorous comparisons of non-invasive scapular tracking techniques. This study evaluated scapular orientation measurement methods across an expanded range of humeral postures. Scapular medial/lateral rotation, anterior/posterior tilt and protraction/retraction was measured using an acromion marker cluster (AMC), a scapular locator, and a reference stylus. Motion was captured using reflective markers on the upper body, as well as on the AMC, locator and stylus. A combination of 5 arm elevation angles, 3 arm elevation planes and 3 arm axial rotations was examined. Measurement method interacted with elevation angle and plane of elevation for all three scapular orientation directions (p < 0.01). Method of measurement interacted with axial rotation in anterior/posterior tilt and protraction/retraction (p < 0.01). The AMC had strong agreement with the reference stylus than the locator for the majority of humeral elevations, planes and axial rotations. The AMC underestimated lateral rotation, with the largest difference of ∼2° at 0° elevation. Both the locator and AMC overestimated posterior tilt at high arm elevation by up to 7.4°. Misestimations from using the locator could be enough to potentially obscure meaningful differences in scapular rotations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Three dimensional thermal stresses in angle-ply composite laminates

    NASA Technical Reports Server (NTRS)

    Griffin, O. Hayden, Jr.

    1988-01-01

    The room temperature stress distributions and shapes of a family of angle ply graphite/epoxy laminates have been obtained using a three-dimensional linear finite element analysis. The sensitivity of the corners to fiber angle variations is examined, in addition to the errors introduced by assuming planes of symmetry which do not exist in angle-ply laminates. The results show that angle ply laminates with 'clustered' plies will tend to delaminate at diagonally opposite corners, and that matrix cracks in this family of laminates will be initiated in the laminate interior.

  18. Eye point-of-regard system

    NASA Technical Reports Server (NTRS)

    Jex, H. R.

    1971-01-01

    System measures intersection of line of sight and eye point of regard /EPR/ for a human operator in visual scanning system. Device measures two head to reference angles with EPR system and adds them with eye to head angles, yielding a dc signal proportional to picture plane coordinates.

  19. Instrument accurately measures weld angle and offset

    NASA Technical Reports Server (NTRS)

    Boyd, W. G.

    1967-01-01

    Weld angle is measured to the nearest arc minute and offset to one thousandth of an inch by an instrument designed to use a reference plane at two locations on a test coupon. A special table for computation has been prepared for use with the instrument.

  20. Flow Behavior in Side-View Plane of Pitching Delta Wing

    NASA Astrophysics Data System (ADS)

    Pektas, Mehmet Can; Tasci, Mehmet Oguz; Karasu, Ilyas; Sahin, Besir; Akilli, Huseyin

    2018-06-01

    In the present investigation, a delta wing which has 70° sweep angle, Λ was oscillated on its midcord according to the equation of α(t)=αm+α0sin(ωet). This study focused on understanding the effect of pitching and characterizing the interaction of vortex breakdown with oscillating leading edges under different yaw angles, β over a slender delta wing. The value of mean angle of attack, αm was taken as 25°. The yaw angle, β was varied with an interval of 4° over the range of 0°≤β≤ 16°. The delta wing was sinusoidally pitched within the range of period of time 5s≤Te≤60s and reduced frequency was set as K=0.16, 0.25, 0.49, 1.96 and lastly amplitude of pitching motion was arranged as α0=±5°.Formations and locations of vortex breakdown were investigated by using the dye visualization technique in side view plane.

  1. Measurement and analysis of a small nozzle plume in vacuum

    NASA Technical Reports Server (NTRS)

    Penko, P. F.; Boyd, I. D.; Meissner, D. L.; Dewitt, K. J.

    1993-01-01

    Pitot pressures and flow angles are measured in the plume of a nozzle flowing nitrogen and exhausting to a vacuum. Total pressures are measured with Pitot tubes sized for specific regions of the plume and flow angles measured with a conical probe. The measurement area for total pressure extends 480 mm (16 exit diameters) downstream of the nozzle exit plane and radially to 60 mm (1.9 exit diameters) off the plume axis. The measurement area for flow angle extends to 160 mm (5 exit diameters) downstream and radially to 60 mm. The measurements are compared to results from a numerical simulation of the flow that is based on kinetic theory and uses the direct-simulation Monte Carlo (DSMC) method. Comparisons of computed results from the DSMC method with measurements of flow angle display good agreement in the far-field of the plume and improve with increasing distance from the exit plane. Pitot pressures computed from the DSMC method are in reasonably good agreement with experimental results over the entire measurement area.

  2. Equilibrium configurations of the conducting liquid surface in a nonuniform electric field

    NASA Astrophysics Data System (ADS)

    Zubarev, N. M.; Zubareva, O. V.

    2011-01-01

    Possible equilibrium configurations of the free surface of a conducting liquid deformed by a nonuniform external electric field are investigated. The liquid rests on an electrode that has the shape of a dihedral angle formed by two intersecting equipotential half-planes (conducting wedge). It is assumed that the problem has plane symmetry: the surface is invariant under shift along the edge of the dihedral angle. A one-parametric family of exact solutions for the shape of the surface is found in which the opening angle of the region above the wedge serves as a parameter. The solutions are valid when the pressure difference between the inside and outside of the liquid is zero. For an arbitrary pressure difference, approximate solutions to the problem are constructed and it is demonstrated the approximation error is small. It is found that, when the potential difference exceeds a certain threshold value, equilibrium solutions are absent. In this case, the region occupied by the liquid disintegrates, the disintegration scenario depending on the opening angle.

  3. Controllability analysis and testing of a novel magnetorheological absorber for field gun recoil mitigation

    NASA Astrophysics Data System (ADS)

    Ouyang, Qing; Zheng, Jiajia; Li, Zhaochun; Hu, Ming; Wang, Jiong

    2016-11-01

    This paper aims to analyze the effects of combined working coils of magnetorheological (MR) absorber on the shock mitigation performance and verify the controllability of MR absorber as applied in the recoil system of a field gun. A physical scale model of the field gun is established and a long-stroke MR recoil absorber with four-stage parallel electromagnetic coils is designed to apply separate current to each stage and generate variable magnetic field distribution in the annular flow channel. Based on dynamic analysis and firing stability conditions of the field gun, ideal recoil force-stroke profiles of MR absorber at different limiting firing angles are obtained. The experimental studies are carried out on an impact test rig under different combinations of current loading: conventional unified control mode, separate control mode and timing control mode. The fullness degree index (FDI) is defined as the quantitative evaluation criterion of the controllability of MR absorber during the whole recoil motion. The results show that the force-stroke profile of the novel MR absorber can approach the ideal curve within 25 degrees of the limiting firing angle through judicious exploitation of the adjustable rheological properties of MR fluid.

  4. Measuring the Radius of the Earth from a Mountain Top Overlooking the Ocean

    ERIC Educational Resources Information Center

    Gangadharan, Dhevan

    2009-01-01

    A clear view of the ocean may be used to measure the radius of the Earth. To an observer looking out at the ocean, the horizon will always form some angle [theta] with the local horizontal plane. As the observer's elevation "h" increases, so does the angle [theta]. From measurements of the elevation "h" and the angle [theta],…

  5. Tank tests to determine the effect of varying design parameters of planing-tail hulls II : effect of varying depth of step, angle of after- body keel, length of afterbody chine, and gross load

    NASA Technical Reports Server (NTRS)

    Dawson, John R; Mckann, Robert; Hay, Elizabeth S

    1946-01-01

    The second part of a series of tests made in Langley tank no. 2 to determine the effect of varying design parameters of planing-tail hulls is presented. Results are given to show the effects on resistance characteristics of varying angle of afterbody keel, depth of step, and length of afterbody chine. The effect of varying the gross load is shown for one configuration. The resistance characteristics of planing-tail hulls are compared with those of a conventional flying-boat hull. The forces on the forebody and afterbody of one configuration are compared with the forces on a conventional hull. Increasing the angle of afterbody keel had small effect on hump resistance and no effect on high-speed resistance but increased free-to-trim resistance at intermediate speeds. Increasing the depth of step increased hump resistance, had little effect on high-speed resistance, and increased free-to-trim resistance at intermediate speeds. Omitting the chines on the forward 25 percent of the afterbody had no appreciable effect on resistance. Omitting 70 percent of the chine length had almost no effect on maximum resistance but broadened the hump and increased spray around the afterbody. Load-resistance ratio at the hump decreased more rapidly with increasing load coefficient for the planing-tail hull than for the representative conventional hull, although the load-resistance ratio at the hump was greater for the planing-tail hull than for the conventional hull throughout the range of loads tested. At speeds higher than hump speed, load-resistance ratio for the planing-tail hull was a maximum at a particular gross load and was slightly less at heavier and lighter gross loads. The planing-tail hull was found to have lower resistance than the conventional hull at both the hump and at high speeds, but at intermediate speeds there was little difference. The lower hump resistance of the planing-tail hull was attributed to the ability of the afterbody to carry a greater percentage of the total load while maintaining a higher value of load-resistance ratio.

  6. Out-of-plane coercive field of Ni 80Fe 20 antidot arrays

    NASA Astrophysics Data System (ADS)

    Gao, Chunhong; Chen, Ke; Lü, Ling; Zhao, Jianwei; Chen, Peng

    2010-11-01

    The out-of-plane magnetic anisotropy and out-of-plane magnetization reversal process of nanoscale Ni 80Fe 20 antidot arrays deposited by magnetron sputtering technique on an anodic aluminum oxide (AAO) membrane are investigated. The angular dependence of out-of-plane remanent magnetization of Ni 80Fe 20 antidot arrays shows that the maximum remanence is in-plane and the squareness of the out-of-plane hysteresis loop follow a |cos θ| dependence. The angular dependence of out-of-plane coercivity of Ni 80Fe 20 antidot arrays shows that the maximum coercivity lies on the surface of a cone with its symmetric axis normal to the sample plane, which indicates a transition of magnetic reversal from curling to coherent rotation when changing the angle between the applied magnetic field and the sample plane.

  7. Cephalometric Evaluation of Children with Allergic Rhinitis and Mouth Breathing.

    PubMed

    Agostinho, Helena Afonso; Furtado, Ivo Ãlvares; Silva, Francisco Salvado; Ustrell Torrent, Josep

    2015-01-01

    Orthodontists frequently treat children with mouth breathing. The purpose of the present study was to examine dental positions, skeletal effects and the pharyngeal airway space of children with chronic allergic rhinitis, when compared with a control group exhibiting a normal breathing pattern. Seventy Caucasian children from Santa Maria University Hospital - North Lisbon Hospital Center were evaluated, between September 2009 and February 2013. The study group comprised of 35 children with chronic allergic rhinitis, both genders, aged 5 - 14, with positive reaction to allergens, mouth breathing and malocclusion. The control group was composed of 35 children, both genders, displaying normal nasal breathing and malocclusion, who resorted to the orthodontic department. Measures of Ricketts, Steiner and McNamara's analysis were used and the t- Student test was applied to the data obtained. Statistically significant differences were observed between the oral and nasal breathers, respectively: lower facial height (49.1/45.9 mm), Frankfurt â mandibular plane angle (30.1/26.9º) and Sela-Nasion - oclusal plane angle (17.3/15º), maxillary length (78.4/82.4 mm), mandibular length (102.4/107 mm), overbite (0.8/3.1mm) and overjet (4/4.7 mm). Comparison between the allergic rhinitis and control group showed that there is an increased lower facial height, larger Frankfurt â mandibular plane angle and Sela-Nasion oclusal plane angle in children with chronic allergic rhinitis. This group also had a shorter maxillary and mandibular length, less overbite and decreased upper airway space. Children with allergic rhinitis and mouth breathing have longer faces, shorter maxillas and mandibles and a narrowed pharyngeal airway space. No statistical differences between the groups in sagital relationships or in dental inclinations were found.

  8. Wind-tunnel acoustic results of two rotor models with several tip designs

    NASA Technical Reports Server (NTRS)

    Martin, R. M.; Connor, A. B.

    1986-01-01

    A three-phase research program has been undertaken to study the acoustic signals due to the aerodynamic interaction of rotorcraft main rotors and tail rotors. During the first phase, two different rotor models with several interchangeable tips were tested in the Langley 4- by 7-Meter Tunnel on the U.S. Army rotor model system. An extensive acoustic data base was acquired, with special emphasis on blade-vortex interaction (BVI) noise. The details of the experimental procedure, acoustic data acquisition, and reduction are documented. The overall sound pressure level (OASPL) of the high-twist rotor systems is relatively insensitive to flight speed but generally increases with rotor tip-path-plane angle. The OASPL of the high-twist rotors is dominated by acoustic energy in the low-frequency harmonics. The OASPL of the low-twist rotor systems shows more dependence on flight speed than the high-twist rotors, in addition to being quite sensitive to tip-path-plane angle. An integrated band-limited sound pressure level, limited by 500 to 3000 Hz, is a useful metric to quantify the occurrence of BVI noise. The OASPL of the low-twist rotors is strongly influenced by the band-limited sound levels, indicating that the blade-vortex impulsive noise is a dominant noise source for this rotor design. The midfrequency acoustic levels for both rotors show a very strong dependence on rotor tip-path-plane angle. The tip-path-plane angle at which the maximum midfrequency sound level occurs consistently decreases with increasing flight speed. The maximum midfrequency sound level measured at a given location is constant regardless of the flight speed.

  9. Artificial in-plane ordering of textured YBa2Cu3O(7-x) films deposited on polycrystalline yttria-stabilized zirconia substrates

    NASA Astrophysics Data System (ADS)

    Harshavardhan, K. S.; Rajeswari, M.; Hwang, D. M.; Chen, C. Y.; Sands, T. D.; Venkatesan, T.; Tkaczyk, J. E.; Lay, K. W.; Safari, A.; Johnson, L.

    1992-12-01

    Anisotropic surface texturing of the polycrystalline yttria-stabilized zirconia substrates, prior to YBa2Cu3O(7-x) film deposition, is shown to promote in-plane (basal plane) ordering of the film growth in addition to the c-axis texturing. The Jc's of the films in the weak-link-dominated low-field regime are enhanced considerably, and this result is attributed to the reduction of weak links resulting from a reduction in the number of in-plane large-angle grain boundaries.

  10. What do nurses and therapists think about the positioning of stroke patients?

    PubMed

    Rowat, A M

    2001-06-01

    At present, there are a number of different positioning strategies for stroke patients, but these are mainly based on clinical experience rather than research. Prior to developing a study to evaluate the effect of positioning on outcome after stroke, it was important to establish if nurses in our hospital had given much thought to the positioning of stroke patients. This study aimed to explore whether nurses working on the stroke unit at a Scottish teaching hospital held different views on the positioning of conscious and unconscious stroke patients to nurses working on other wards with stroke patients and therapists. Questionnaires on various aspects of patient positioning were sent to 150 nurses and 25 therapists working in five specialities where stroke patients are cared for in a large teaching hospital. Overall, the majority of nurses and therapists (74%) believed that the best position for conscious stroke patients was sitting in a chair. Also, 80% of them believed that the best position for unconscious stroke patients was lying on the nonparetic side. There was less of a consensus between nurses and therapists working in the five specialities as to whether it was appropriate for conscious or unconscious stroke patients to lie on their paretic side, lie supine or sit propped-up in bed in either a 30 or 70 degrees angle. The lack of consensus between nurses working in the five specialities is probably because at present there is little research to guide nursing practices for the positioning of stroke patients. Therefore, research to confirm which positions improves or hinders outcome after stroke is essential. Indeed, positioning is a simple inexpensive strategy, which could have a substantial public health impact, as stroke is so common.

  11. Quantification of shoulder and elbow passive moments in the sagittal plane as a function of adjacent angle fixations.

    PubMed

    Kodek, Timotej; Munih, Marko

    2003-01-01

    The goal of this study was an assessment of the shoulder and elbow joint passive moments in the sagittal plane for six healthy individuals. Either the shoulder or elbow joints were moved at a constant speed, very slowly throughout a large portion of their range by means of an industrial robot. During the whole process the arm was held fully passively, while the end point force data and the shoulder, elbow and wrist angle data were collected. The presented method unequivocally reveals a large passive moment adjacent angle dependency in the central angular range, where most everyday actions are performed. It is expected to prove useful in the future work when examining subjects with neuromuscular disorders. Their passive moments may show a fully different pattern than the ones obtained in this study.

  12. Variable angle-of-incidence polarization-sensitive optical coherence tomography: its use to study the 3D collagen structure of equine articular cartilage

    NASA Astrophysics Data System (ADS)

    Ugryumova, Nadya; Gangnus, Sergei V.; Matcher, Stephen J.

    2006-02-01

    Polarization-sensitive optical coherence tomography has been used to spatially map the birefringence of equine articular cartilage. The polar orientation of the collagen fibers relative to the plane of the joint surface must be taken into account if a quantitative measurement of true birefringence is required. Using a series of images taken at different angles of illumination, we determine the fiber polar angle and true birefringence at one site on a sample of equine cartilage, on the assumption that the fibers lie within the plane of imaging. We propose a more general method based on the extended Jones matrix formalism to determine both the polar and azimuthal orientation of the collagen fibers as well as the true birefringence as functions of depth.

  13. Back focal plane microscopic ellipsometer with internal reflection geometry

    NASA Astrophysics Data System (ADS)

    Otsuki, Soichi; Murase, Norio; Kano, Hiroshi

    2013-05-01

    A back focal plane (BFP) ellipsometer is presented to measure a thin film on a cover glass using an oil-immersion high-numerical-aperture objective lens. The internal reflection geometry lowers the pseudo Brewster angle (ϕB) to the range over which the light distribution is observed in BFP of the objective. A calculation based on Mueller matrix was developed to compute ellipsometric parameters from the intensity distribution on BFP. The center and radius of the partial reflection region below the critical angle were determined and used to define a polar coordinate on BFP. Harmonic components were computed from the intensities along the azimuth direction and transformed to ellipsometric parameters at multiple incident angles around ϕB. The refractive index and thickness of the film and the contributions of the objective effect were estimated at the same time by fitting.

  14. Methyl 6-eth-oxy-3-phenyl-3a,4-dihydro-3H-chromeno[4,3-c]isoxazole-3a-car-boxylate.

    PubMed

    Suresh, G; Srinivasan, J; Bakthadoss, M; Aravindhan, S

    2013-02-01

    In the title compound, C(20)H(19)NO(5), the dihedral angle between the mean plane of the pyran ring (which has a half-chair conformation) and the benzene ring of the chromeno ring system is 7.21 (7)°. The dihedral angle between the mean plane of the chromeno ring system and the isoxazole ring is 21.78 (6)°, while the isoxazole ring forms a dihedral angle of 72.60 (8)° with the attached phenyl ring. In the crystal, mol-ecules are linked via pairs of C-H⋯O hydrogen bonds, forming inversion dimers with an R(2) (2)(10) ring motif. These dimers are linked via C-H⋯N hydrogen bonds, forming chains along [001].

  15. Estimating the Value of the Inclination Angle of the Lunar Plane to the Ecliptic Plane

    ERIC Educational Resources Information Center

    Isildak, R. Suat; Isik, Hakan; Küçüközer, H. Asuman

    2018-01-01

    Sky appears to our students as a vast volume surrounding the Earth. The most striking astronomical events that they can witness in the sky are lunar phases and eclipses. However, eclipses do not occur as often as full and new phases of the Moon. This difference is due to the fact that the orbital planes of the Moon and the Earth do not overlap.…

  16. Design and Realization of a Three Degrees of Freedom Displacement Measurement System Composed of Hall Sensors Based on Magnetic Field Fitting by an Elliptic Function

    PubMed Central

    Zhao, Bo; Wang, Lei; Tan, Jiu-Bin

    2015-01-01

    This paper presents the design and realization of a three degrees of freedom (DOFs) displacement measurement system composed of Hall sensors, which is built for the XYθz displacement measurement of the short stroke stage of the reticle stage of lithography. The measurement system consists of three pairs of permanent magnets mounted on the same plane on the short stroke stage along the Y, Y, X directions, and three single axis Hall sensors correspondingly mounted on the frame of the reticle stage. The emphasis is placed on the decoupling and magnetic field fitting of the three DOFs measurement system. The model of the measurement system is illustrated, and the XY positions and θZ rotation of the short stroke stage can be obtained by decoupling the sensor outputs. A magnetic field fitting by an elliptic function-based compensation method is proposed. The practical field intensity of a permanent magnet at a certain plane height can be substituted for the output voltage of a Hall sensors, which can be expressed by the elliptic function through experimental data as the crucial issue to calculate the three DOFs displacement. Experimental results of the Hall sensor displacement measurement system are presented to validate the proposed three DOFs measurement system. PMID:26370993

  17. Reduction of genu recurvatum through adjustment of plantarflexion resistance of an articulated ankle-foot orthosis in individuals post stroke

    PubMed Central

    Kobayashi, Toshiki; Orendurff, Michael S.; Singer, Madeline L.; Gao, Fan; Daly, Wayne K.; Foreman, K. Bo

    2016-01-01

    Background Genu recurvatum (knee hyperextension) is a common issue for individuals post stroke. Ankle-foot orthoses are used to improve genu recurvatum, but evidence is limited concerning their effectiveness. Therefore, the aim of this study was to investigate the effect of changing the plantarflexion resistance of an articulated ankle-foot orthosis on genu recurvatum in patients post stroke. Methods Gait analysis was performed on 6 individuals post stroke with genu recurvatum using an articulated ankle-foot orthosis whose plantarflexion resistance was adjustable at four levels. Gait data were collected using a Bertec split-belt instrumented treadmill in a 3-dimensional motion analysis laboratory. Gait parameters were extracted and plotted for each subject under the four plantarflexion resistance conditions of the ankle-foot orthosis. Gait parameters included: a) peak ankle plantarflexion angle, b) peak ankle dorsiflexion moment, c) peak knee extension angle and d) peak knee flexion moment. A non-parametric Friedman test was performed followed by a post-hoc Wilcoxon Signed-Rank test for statistical analyses. Findings All the gait parameters demonstrated statistically significant differences among the four resistance conditions of the AFO. Increasing the amount of plantarflexion resistance of the ankle-foot orthosis generally reduced genu recurvatum in all subjects. However, individual analyses showed that the responses to the changes in the plantarflexion resistance of the AFO were not necessarily linear, and appear unique to each subject. Interpretations The plantarflexion resistance of an articulated AFO should be adjusted to improve genu recurvatum in patients post stroke. Future studies should investigate what clinical factors would influence the individual differences. PMID:27136122

  18. Effect of body mass index on hemiparetic gait.

    PubMed

    Sheffler, Lynne R; Bailey, Stephanie Nogan; Gunzler, Douglas; Chae, John

    2014-10-01

    To evaluate the relationship between body mass index (BMI) and spatiotemporal, kinematic, and kinetic gait parameters in chronic hemiparetic stroke survivors. Secondary analysis of data collected in a randomized controlled trial comparing two 12-week ambulation training treatments. Academic medical center. Chronic hemiparetic stroke survivors (N = 108, >3 months poststroke) Linear regression analyses were performed of BMI, and selected pretreatment gait parameters were recorded using quantitative gait analysis. Spatiotemporal, kinematic, and kinetic gait parameters. A series of linear regression models that controlled for age, gender, stroke type (ischemic versus hemorrhagic), interval poststroke, level of motor impairment (Fugl-Meyer score), and walking speed found BMI to be positively associated with step width (m) (β = 0.364, P < .001), positively associated with peak hip abduction angle of the nonparetic limb during stance (deg) (β = 0.177, P = .040), negatively associated with ankle dorsiflexion angle at initial contact of the paretic limb (deg) (β = -0.222, P = .023), and negatively associated with peak ankle power at push-off (W/kg) of the paretic limb (W/kg)(β = -0.142, P = .026). When walking at a similar speed, chronic hemiparetic stroke subjects with a higher BMI demonstrated greater step width, greater hip hiking of the paretic lower limb, less paretic limb dorsiflexion at initial contact, and less paretic ankle power at push-off as compared to stroke subjects with a lower BMI and similar level of motor impairment. Further studies are necessary to determine the clinical relevance of these findings with respect to rehabilitation strategies for gait dysfunction in hemiparetic patients with higher BMIs. Copyright © 2014 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  19. On hydrodynamics of drag and lift of the human arm.

    PubMed

    Gardano, Paola; Dabnichki, Peter

    2006-01-01

    The work presents results on drag and lift measurement conducted in a low speed wind tunnel on a replica of the entire human arm. The selected model positions were identical to those during purely rotational front crawl stroke in quasi-static conditions. A computational fluid dynamics model using Fluent showed close correspondence with the experimental results and confirmed the suitability of low speed wind tunnel for the drag and lift measurement in quasi-static conditions. The obtained profiles of the hydrodynamic forces were similar to the dynamic data presented in an earlier study suggesting that shape drag is a major contributing factor in propulsive force generation. The aim of this study was to underline the importance of the entire arm analysis, the elbow angle and a newly defined angle of attack representing the angle of shoulder rotation. It was found that both the maximum value of the drag force at 160 degrees elbow flexion angle and the momentum generated by it exceed the respective magnitudes for the fully extended arm. The latter is underlined by a prolonged plateau of near maximum drag that was obtained at shoulder angle range of 50-140 degrees suggesting that optimal arm configuration in terms of propulsive force generation requires elbow flexion. Furthermore it was found that drag trend is not consistent with the widely assumed and used sinus wave profile. A gap in the existing experimental research was filled as for the first time the entire arm lift and drag was measured across the entire stroke range.

  20. Free-surface phenomena under low- and zero-gravity conditions

    NASA Technical Reports Server (NTRS)

    Coles, D.

    1985-01-01

    An apparatus to measure contact angle was constructed to exploit the proposed internal-corner criterion. If 2 alfa is the internal angle between two intersecting vertical planes and gamma is the contact angle, a meniscus at the corner rises to a finite height if alfa + gamma pi/2 and to an infinite height if alfa + gamma pi/2. The apparatus operates by decreasing the angle alfa from pi/2 until the meniscus height changes abruptly. A number of liquids are tested on glass and plexiglas.

  1. Glenoid deformity in the coronal plane correlates with humeral head changes in osteoarthritis: a radiographic analysis.

    PubMed

    Hawi, Nael; Magosch, Petra; Tauber, Mark; Lichtenberg, Sven; Martetschläger, Frank; Habermeyer, Peter

    2017-02-01

    A variety of measurements can be used to assess radiographic osteoarthritic changes of the shoulder. This study aimed to analyze the correlation between the radiographic humeral-sided Samilson and Prieto classification system and 3 different radiographic classifications describing the changes of the glenoid in the coronal plane. The study material included standardized radiographs of 50 patients with idiopathic osteoarthritis before anatomic shoulder replacement. On the basis of radiographic measurements, the cases were evaluated using the Samilson and Prieto grading system, angle β, inclination type, and critical shoulder angle by 2 independent observers. Classification measurements showed an excellent agreement between observers. Our results showed that the humeral-sided Samilson and Prieto grading system had a statistically significant good correlation with angle β (observer 1, r = 0.74; observer 2, r = 0.77; P < .05) and a statistically significant excellent correlation with the inclination type of the glenoid (observer 1, r  = 0.86; observer 2, r = 0.8; P < .05). A poor correlation to the critical shoulder angle was observed (r = -0.14, r = 0.03; P > .05). The grade of humeral-sided osteoarthritis according to Samilson and Prieto correlates with the glenoid-sided osteoarthritic changes of the glenoid in the coronal plane described by the angle β and by the inclination type of the glenoid. Higher glenoid-sided inclination is associated with higher grade of osteoarthritis in primary shoulder osteoarthritis. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  2. Planar covariance of upper and lower limb elevation angles during hand-foot crawling in healthy young adults.

    PubMed

    MacLellan, M J; Catavitello, G; Ivanenko, Y P; Lacquaniti, F

    2017-11-01

    Habitual quadrupeds have been shown to display a planar covariance of segment elevation angle waveforms in the fore and hind limbs during many forms of locomotion. The purpose of the current study was to determine if humans generate similar patterns in the upper and lower limbs during hand-foot crawling. Nine healthy young adults performed hand-foot crawling on a treadmill at speeds of 1, 2, and 3 km/h. A principal component analysis (PCA) was applied to the segment elevation angle waveforms for the upper (upper arm, lower arm, and hand) and lower (thigh, shank, and foot) limbs separately. The planarity of the elevation angle waveforms was determined using the sum of the variance explained by the first two PCs and the orientation of the covariance plane was quantified using the direction cosines of the eigenvector orthogonal to the plane, projected upon each of the segmental semi-axes. Results showed that planarity of segment elevation angles was maintained in the upper and lower limbs (explained variance >97%), although a slight decrease was present in the upper limb when crawling at 3 km/h. The orientation of the covariance plane was highly limb-specific, consistent with animal studies and possibly related to the functional neural control differences between the upper and lower limbs. These results may suggest that the motor patterns stored in the central nervous system for quadrupedal locomotion may be retained through evolution and may still be exploited when humans perform such tasks.

  3. Compensating for Electro-Osmosis in Electrophoresis

    NASA Technical Reports Server (NTRS)

    Rhodes, Percy H.; Snyder, Robert S.

    1987-01-01

    Simple mechanical adjustment eliminates transverse velocity component. New apparatus for moving-wall electrophoresis increases degree of collimation of chemical species in sample stream. Electrophoresis chamber set at slight angle in horizontal plane to adjust angle between solution flow and wall motion. Component of velocity created cancels electro-osmotic effect.

  4. Power of the wingbeat: modelling the effects of flapping wings in vertebrate flight.

    PubMed

    Heerenbrink, M Klein; Johansson, L C; Hedenström, A

    2015-05-08

    Animal flight performance has been studied using models developed for man-made aircraft. For an aeroplane with fixed wings, the energetic cost as a function of flight speed can be expressed in terms of weight, wing span, wing area and body area, where more details are included in proportionality coefficients. Flying animals flap their wings to produce thrust. Adopting the fixed wing flight model implicitly incorporates the effects of wing flapping in the coefficients. However, in practice, these effects have been ignored. In this paper, the effects of reciprocating wing motion on the coefficients of the fixed wing aerodynamic power model for forward flight are explicitly formulated in terms of thrust requirement, wingbeat frequency and stroke-plane angle, for optimized wingbeat amplitudes. The expressions are obtained by simulating flights over a large parameter range using an optimal vortex wake method combined with a low-level blade element method. The results imply that previously assumed acceptable values for the induced power factor might be strongly underestimated. The results also show the dependence of profile power on wing kinematics. The expressions introduced in this paper can be used to significantly improve animal flight models.

  5. Power of the wingbeat: modelling the effects of flapping wings in vertebrate flight

    PubMed Central

    Heerenbrink, M. Klein; Johansson, L. C.; Hedenström, A.

    2015-01-01

    Animal flight performance has been studied using models developed for man-made aircraft. For an aeroplane with fixed wings, the energetic cost as a function of flight speed can be expressed in terms of weight, wing span, wing area and body area, where more details are included in proportionality coefficients. Flying animals flap their wings to produce thrust. Adopting the fixed wing flight model implicitly incorporates the effects of wing flapping in the coefficients. However, in practice, these effects have been ignored. In this paper, the effects of reciprocating wing motion on the coefficients of the fixed wing aerodynamic power model for forward flight are explicitly formulated in terms of thrust requirement, wingbeat frequency and stroke-plane angle, for optimized wingbeat amplitudes. The expressions are obtained by simulating flights over a large parameter range using an optimal vortex wake method combined with a low-level blade element method. The results imply that previously assumed acceptable values for the induced power factor might be strongly underestimated. The results also show the dependence of profile power on wing kinematics. The expressions introduced in this paper can be used to significantly improve animal flight models. PMID:27547098

  6. Virtual reality using guided imagery to create Kanji or Hiragana by computer graphics: I

    NASA Astrophysics Data System (ADS)

    Ishigame, Masaaki; Miura, Nozomu; Hosaka, Akiko

    1997-04-01

    We have been studying a kind of word-processor that is able to create Japanese characters, Kanji or Hiragana strings in the cursive style, using an electronic writing brush model. Int his paper, we describe in detail the operation characteristics of the electronic writing brush which we have proposed. We defined a touch shape pattern of the electronic writing brush as a form which is projected as a circle and a cone. The brush goes on certain points of the skeleton of the character figure which is given as skeleton data. The thickness of the line is determined by a diametric variable brush pressure. Our progressive action model can rotate the direction of the writing brush tip corresponding to the difference angle between the direction of brush tip and the direction of the brush movement, and also the softness of the writing brush to express the writing brush method called the side writing brush. The front side and back side of the writing brush can be expressed in a calligraphic drawing. With our technique we can draw characters in actual stroke order on a virtual computer plane as if they are written by an actual writing brush.

  7. Nanostructured carbon films with oriented graphitic planes

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

    Teo, E. H. T.; Kalish, R.; Kulik, J.

    2011-03-21

    Nanostructured carbon films with oriented graphitic planes can be deposited by applying energetic carbon bombardment. The present work shows the possibility of structuring graphitic planes perpendicular to the substrate in following two distinct ways: (i) applying sufficiently large carbon energies for deposition at room temperature (E>10 keV), (ii) utilizing much lower energies for deposition at elevated substrate temperatures (T>200 deg. C). High resolution transmission electron microscopy is used to probe the graphitic planes. The alignment achieved at elevated temperatures does not depend on the deposition angle. The data provides insight into the mechanisms leading to the growth of oriented graphiticmore » planes under different conditions.« less

  8. Utilization of optical tracking to validate a software-driven isocentric approach to robotic couch movements for proton radiotherapy.

    PubMed

    Hsi, Wen C; Law, Aaron; Schreuder, Andreas N; Zeidan, Omar A

    2014-08-01

    An optical tracking and positioning system (OTPS) was developed to validate the software-driven isocentric (SDI) approach to control the six-degrees-of-freedom movement of a robotic couch. The SDI approach to movements rotating around a predefined isocenter, referred to as a GeoIso, instead of a mechanical pivot point was developed by the robot automation industry. With robotic couch-sag corrections for weight load in a traditional SDI approach, movements could be accurately executed for a GeoIso located within a 500 mm cubic volume on the couch for treatments. The accuracy of SDI movement was investigated using the OTPS. The GeoIso was assumed to align with the proton beam isocenter (RadIso) for gantry at the reference angle. However, the misalignment between GeoIso and RadIso was quantitatively investigated by measuring the displacements at various couch angles for a target placed at the RadIso at an initial couch angle. When circular target displacements occur on a plane, a relative isocenter shift (RIS) correction could be applied in the SDI movement to minimize target displacements. Target displacements at a fixed gantry angle without and with RIS correction were measured for 12 robotic couches. Target displacements for various gantry angles were performed on three couches in gantry rooms to study the gantry-induced RadIso shift. The RIS correction can also be applied for the RadIso shift. A new SDI approach incorporating the RIS correction with the couch sag is described in this study. In parallel, the accuracy of SDI translation movements for various weight loads of patients on the couch was investigated during positioning of patients for proton prostate treatments. For a fixed gantry angle, measured target displacements without RIS correction for couch rotations in the horizontal plane varied from 4 to 20 mm. However, measured displacements perpendicular to couch rotation plane were about 2 mm for all couches. Extracted misalignments of GeoIso and RadIso in the horizontal plane were about 10 mm for one couch and within 3 mm for the rest of couches. After applying the RIS correction, the residual target displacements for couch rotations were within 0.5 mm to RadIso for all couches. For various gantry angles, measured target location for each angle was within 0.5 mm to its excepted location by the preset RadIso shift. Measured target displacements for ± 30° of couch rotations were within 0.5 mm for gantry angles at 0° and 180°. Overall, nearly 85% of couch movements were within 0.5 mm in the horizontal plane and 0.7 mm vector distance from required displacements. The authors present an optical tracking methodology to quantify for software-driven isocentric movements of robotic couches. By applying proper RIS correction for misaligned GeoIso and RadIso for each couch, and the RadIso shifts for a moving gantry, residual target displacements for isocentric couch movements around the actual RadIso can be reduced to submillimeter tolerance.

  9. Utilization of optical tracking to validate a software-driven isocentric approach to robotic couch movements for proton radiotherapy

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

    Hsi, Wen C., E-mail: Wen.Hsi@Mclaren.org, E-mail: Wenchien.hsi@sphic.org.cn; Zeidan, Omar A., E-mail: omar.zeidan@orlandohealth.com; Law, Aaron

    Purpose: An optical tracking and positioning system (OTPS) was developed to validate the software-driven isocentric (SDI) approach to control the six-degrees-of-freedom movement of a robotic couch. Methods: The SDI approach to movements rotating around a predefined isocenter, referred to as a GeoIso, instead of a mechanical pivot point was developed by the robot automation industry. With robotic couch-sag corrections for weight load in a traditional SDI approach, movements could be accurately executed for a GeoIso located within a 500 mm cubic volume on the couch for treatments. The accuracy of SDI movement was investigated using the OTPS. The GeoIso wasmore » assumed to align with the proton beam isocenter (RadIso) for gantry at the reference angle. However, the misalignment between GeoIso and RadIso was quantitatively investigated by measuring the displacements at various couch angles for a target placed at the RadIso at an initial couch angle. When circular target displacements occur on a plane, a relative isocenter shift (RIS) correction could be applied in the SDI movement to minimize target displacements. Target displacements at a fixed gantry angle without and with RIS correction were measured for 12 robotic couches. Target displacements for various gantry angles were performed on three couches in gantry rooms to study the gantry-induced RadIso shift. The RIS correction can also be applied for the RadIso shift. A new SDI approach incorporating the RIS correction with the couch sag is described in this study. In parallel, the accuracy of SDI translation movements for various weight loads of patients on the couch was investigated during positioning of patients for proton prostate treatments. Results: For a fixed gantry angle, measured target displacements without RIS correction for couch rotations in the horizontal plane varied from 4 to 20 mm. However, measured displacements perpendicular to couch rotation plane were about 2 mm for all couches. Extracted misalignments of GeoIso and RadIso in the horizontal plane were about 10 mm for one couch and within 3 mm for the rest of couches. After applying the RIS correction, the residual target displacements for couch rotations were within 0.5 mm to RadIso for all couches. For various gantry angles, measured target location for each angle was within 0.5 mm to its excepted location by the preset RadIso shift. Measured target displacements for ±30° of couch rotations were within 0.5 mm for gantry angles at 0° and 180°. Overall, nearly 85% of couch movements were within 0.5 mm in the horizontal plane and 0.7 mm vector distance from required displacements. Conclusions: The authors present an optical tracking methodology to quantify for software-driven isocentric movements of robotic couches. By applying proper RIS correction for misaligned GeoIso and RadIso for each couch, and the RadIso shifts for a moving gantry, residual target displacements for isocentric couch movements around the actual RadIso can be reduced to submillimeter tolerance.« less

  10. Exhaust after-treatment system with in-cylinder addition of unburnt hydrocarbons

    DOEpatents

    Coleman, Gerald N.; Kesse, Mary L.

    2007-10-30

    Certain exhaust after-treatment devices, at least periodically, require the addition of unburnt hydrocarbons in order to create reductant-rich exhaust conditions. The present disclosure adds unburnt hydrocarbons to exhaust from at least one combustion chamber by positioning, at least partially within a combustion chamber, a mixed-mode fuel injector operable to inject fuel into the combustion chamber in a first spray pattern with a small average angle relative to a centerline of the combustion chamber and a second spray pattern with a large average angle relative to the centerline of the combustion chamber. An amount of fuel is injected in the first spray pattern into a non-combustible environment within the at least one combustion chamber during at least one of an expansion stroke and exhaust stroke. The exhaust with the unburnt amount of fuel is moved into an exhaust passage via an exhaust valve.

  11. Relationship Between Hand Contact Angle and Shoulder Loading During Manual Wheelchair Propulsion by Individuals with Paraplegia

    PubMed Central

    Mulroy, Sara J.; Ruparel, Puja; Hatchett, Patricia E.; Haubert, Lisa Lighthall; Eberly, Valerie J.; Gronley, JoAnne K.

    2015-01-01

    Background: Shoulder loading during manual wheelchair propulsion (WCP) contributes to the development of shoulder pain in individuals with spinal cord injury (SCI). Objective: To use regression analysis to investigate the relationships between the hand contact angle (location of the hand on the pushrim at initial contact and release during the push phase of the WCP cycle) with propulsion characteristics, pushrim forces, and shoulder kinetics during WCP in individuals with paraplegia. Methods: Biomechanical data were collected from 222 individuals (198 men and 24 women) with paraplegia from SCI during WCP on a stationary ergometer at a self-selected speed. The average age of participants was 34.7 years (±9.3), mean time since SCI was 9.3 years (±6.1), and average body weight was 74.4 kg (±15.9). The majority (n = 127; 56%) of participants had lower level paraplegia (T8 to L5) and 95 (42%) had high paraplegia (T2 to T7). Results: Increased push arc (mean = 75.3°) was associated with greater velocity (R = 0.384, P < .001) and cycle distance (R = 0.658, P < .001) and reduced cadence (R = -0.419, P < .001). Initial contact angle and hand release angles were equally associated with cycle distance and cadence, whereas a more anterior release angle was associated with greater velocity (R = 0.372, P < .001). When controlling for body weight, a more posterior initial contact angle was associated with greater posterior shoulder net joint force (R = 0.229, P = .001) and greater flexor net joint moment (R = 0.204, P = .002), whereas a more anterior hand release angle was significantly associated with increased vertical (R = 0.270, P < .001) and greater lateral (R = .293, P < .001) pushrim forces; greater shoulder net joint forces in all 3 planes — posterior (R = 0.164, P = .015), superior (R = 0.176, P = .009), and medial (R = 0.284, P < .001); and greater external rotator (R = 0.176, P = .009) and adductor (R = 0.259, P = .001) net joint moments. Conclusions: Current clinical practice guidelines recommend using long, smooth strokes during manual WCP to reduce peak shoulder forces and to prevent shoulder pain development. The position of the hand at both initial contact and hand release must be considered in WCP training. It is recommended that participants should reach back to initiate contact with the pushrim to maximize push arc but avoid a more anterior hand position at release, because this could increase shoulder load during the push phase of WCP. PMID:26689696

  12. Relationship Between Hand Contact Angle and Shoulder Loading During Manual Wheelchair Propulsion by Individuals with Paraplegia.

    PubMed

    Requejo, Philip Santos; Mulroy, Sara J; Ruparel, Puja; Hatchett, Patricia E; Haubert, Lisa Lighthall; Eberly, Valerie J; Gronley, JoAnne K

    2015-01-01

    Shoulder loading during manual wheelchair propulsion (WCP) contributes to the development of shoulder pain in individuals with spinal cord injury (SCI). To use regression analysis to investigate the relationships between the hand contact angle (location of the hand on the pushrim at initial contact and release during the push phase of the WCP cycle) with propulsion characteristics, pushrim forces, and shoulder kinetics during WCP in individuals with paraplegia. Biomechanical data were collected from 222 individuals (198 men and 24 women) with paraplegia from SCI during WCP on a stationary ergometer at a self-selected speed. The average age of participants was 34.7 years (±9.3), mean time since SCI was 9.3 years (±6.1), and average body weight was 74.4 kg (±15.9). The majority (n = 127; 56%) of participants had lower level paraplegia (T8 to L5) and 95 (42%) had high paraplegia (T2 to T7). Increased push arc (mean = 75.3°) was associated with greater velocity (R = 0.384, P < .001) and cycle distance (R = 0.658, P < .001) and reduced cadence (R = -0.419, P <.001). Initial contact angle and hand release angles were equally associated with cycle distance and cadence, whereas a more anterior release angle was associated with greater velocity (R = 0.372, P < .001). When controlling for body weight, a more posterior initial contact angle was associated with greater posterior shoulder net joint force (R = 0.229, P = .001) and greater flexor net joint moment (R = 0.204, P = .002), whereas a more anterior hand release angle was significantly associated with increased vertical (R = 0.270, P < .001) and greater lateral (R = .293, P < .001) pushrim forces; greater shoulder net joint forces in all 3 planes - posterior (R = 0.164, P = .015), superior (R = 0.176, P = .009), and medial (R = 0.284, P < .001); and greater external rotator (R = 0.176, P = .009) and adductor (R = 0.259, P = .001) net joint moments. Current clinical practice guidelines recommend using long, smooth strokes during manual WCP to reduce peak shoulder forces and to prevent shoulder pain development. The position of the hand at both initial contact and hand release must be considered in WCP training. It is recommended that participants should reach back to initiate contact with the pushrim to maximize push arc but avoid a more anterior hand position at release, because this could increase shoulder load during the push phase of WCP.

  13. Aerodynamics and flow features of a damselfly in takeoff flight.

    PubMed

    Bode-Oke, Ayodeji T; Zeyghami, Samane; Dong, Haibo

    2017-09-26

    Flight initiation is fundamental for survival, escape from predators and lifting payload from one place to another in biological fliers and can be broadly classified into jumping and non-jumping takeoffs. During jumping takeoffs, the legs generate most of the initial impulse. Whereas the wings generate most of the forces in non-jumping takeoffs, which are usually voluntary, slow, and stable. It is of great interest to understand how these non-jumping takeoffs occur and what strategies insects use to generate large amount of forces required for this highly demanding flight initiation mode. Here, for the first time, we report accurate wing and body kinematics measurements of a damselfly during a non-jumping takeoff. Furthermore, using a high fidelity computational fluid dynamics simulation, we identify the 3D flow features and compute the wing aerodynamics forces to unravel the key mechanisms responsible for generating large flight forces. Our numerical results show that a damselfly generates about three times its body weight during the first half-stroke for liftoff. In generating these forces, the wings flap through a steeply inclined stroke plane with respect to the horizon, slicing through the air at high angles of attack (45°-50°). Consequently, a leading edge vortex (LEV) is formed during both the downstroke and upstroke on all the four wings. The formation of the LEV, however, is inhibited in the subsequent upstrokes following takeoff. Accordingly, we observe a drastic reduction in the magnitude of the aerodynamic force, signifying the importance of LEV in augmenting force production. Our analysis also shows that forewing-hindwing interaction plays a favorable role in enhancing both lift and thrust production during takeoff.

  14. Rules to fly by: pigeons navigating horizontal obstacles limit steering by selecting gaps most aligned to their flight direction.

    PubMed

    Ros, Ivo G; Bhagavatula, Partha S; Lin, Huai-Ti; Biewener, Andrew A

    2017-02-06

    Flying animals must successfully contend with obstacles in their natural environments. Inspired by the robust manoeuvring abilities of flying animals, unmanned aerial systems are being developed and tested to improve flight control through cluttered environments. We previously examined steering strategies that pigeons adopt to fly through an array of vertical obstacles (VOs). Modelling VO flight guidance revealed that pigeons steer towards larger visual gaps when making fast steering decisions. In the present experiments, we recorded three-dimensional flight kinematics of pigeons as they flew through randomized arrays of horizontal obstacles (HOs). We found that pigeons still decelerated upon approach but flew faster through a denser array of HOs compared with the VO array previously tested. Pigeons exhibited limited steering and chose gaps between obstacles most aligned to their immediate flight direction, in contrast to VO navigation that favoured widest gap steering. In addition, pigeons navigated past the HOs with more variable and decreased wing stroke span and adjusted their wing stroke plane to reduce contact with the obstacles. Variability in wing extension, stroke plane and wing stroke path was greater during HO flight. Pigeons also exhibited pronounced head movements when negotiating HOs, which potentially serve a visual function. These head-bobbing-like movements were most pronounced in the horizontal (flight direction) and vertical directions, consistent with engaging motion vision mechanisms for obstacle detection. These results show that pigeons exhibit a keen kinesthetic sense of their body and wings in relation to obstacles. Together with aerodynamic flapping flight mechanics that favours vertical manoeuvring, pigeons are able to navigate HOs using simple rules, with remarkable success.

  15. Effect of Gravity on Robot-Assisted Motor Training After Chronic Stroke: A Randomized Trial

    PubMed Central

    Conroy, Susan S.; Whitall, Jill; Dipietro, Laura; Jones-Lush, Lauren M.; Zhan, Min; Finley, Margaret A.; Wittenberg, George F.; Krebs, Hermano I.; Bever, Christopher T.

    2015-01-01

    Objectives To determine the efficacy of 2 distinct 6-week robot-assisted reaching programs compared with an intensive conventional arm exercise program (ICAE) for chronic, stroke-related upper-extremity (UE) impairment. To examine whether the addition of robot-assisted training out of the horizontal plane leads to improved outcomes. Design Randomized controlled trial, single-blinded, with 12-week follow-up. Setting Research setting in a large medical center. Participants Adults (N=62) with chronic, stroke-related arm weakness stratified by impairment severity using baseline UE motor assessments. Interventions Sixty minutes, 3 times a week for 6 weeks of robot-assisted planar reaching (gravity compensated), combined planar with vertical robot-assisted reaching, or intensive conventional arm exercise program. Main Outcome Measure UE Fugl-Meyer Assessment (FMA) mean change from baseline to final training. Results All groups showed modest gains in the FMA from baseline to final with no significant between group differences. Most change occurred in the planar robot group (mean change ± SD, 2.94± 0.77; 95% confidence interval [CI], 1.40 – 4.47). Participants with greater motor impairment (n=41) demonstrated a larger difference in response (mean change ± SD, 2.29±0.72; 95% CI, 0.85–3.72) for planar robot-assisted exercise compared with the intensive conventional arm exercise program (mean change ± SD, 0.43±0.72; 95% CI, −1.00 to 1.86). Conclusions Chronic UE deficits because of stroke are responsive to intensive motor task training. However, training outside the horizontal plane in a gravity present environment using a combination of vertical with planar robots was not superior to training with the planar robot alone. PMID:21849168

  16. Rules to fly by: pigeons navigating horizontal obstacles limit steering by selecting gaps most aligned to their flight direction

    PubMed Central

    Ros, Ivo G.; Bhagavatula, Partha S.; Lin, Huai-Ti

    2017-01-01

    Flying animals must successfully contend with obstacles in their natural environments. Inspired by the robust manoeuvring abilities of flying animals, unmanned aerial systems are being developed and tested to improve flight control through cluttered environments. We previously examined steering strategies that pigeons adopt to fly through an array of vertical obstacles (VOs). Modelling VO flight guidance revealed that pigeons steer towards larger visual gaps when making fast steering decisions. In the present experiments, we recorded three-dimensional flight kinematics of pigeons as they flew through randomized arrays of horizontal obstacles (HOs). We found that pigeons still decelerated upon approach but flew faster through a denser array of HOs compared with the VO array previously tested. Pigeons exhibited limited steering and chose gaps between obstacles most aligned to their immediate flight direction, in contrast to VO navigation that favoured widest gap steering. In addition, pigeons navigated past the HOs with more variable and decreased wing stroke span and adjusted their wing stroke plane to reduce contact with the obstacles. Variability in wing extension, stroke plane and wing stroke path was greater during HO flight. Pigeons also exhibited pronounced head movements when negotiating HOs, which potentially serve a visual function. These head-bobbing-like movements were most pronounced in the horizontal (flight direction) and vertical directions, consistent with engaging motion vision mechanisms for obstacle detection. These results show that pigeons exhibit a keen kinesthetic sense of their body and wings in relation to obstacles. Together with aerodynamic flapping flight mechanics that favours vertical manoeuvring, pigeons are able to navigate HOs using simple rules, with remarkable success. PMID:28163883

  17. Leg orientation as a clinical sign for pusher syndrome

    PubMed Central

    Johannsen, Leif; Broetz, Doris; Karnath, Hans-Otto

    2006-01-01

    Background Effective control of (upright) body posture requires a proper representation of body orientation. Stroke patients with pusher syndrome were shown to suffer from severely disturbed perception of own body orientation. They experience their body as oriented 'upright' when actually tilted by nearly 20° to the ipsilesional side. Thus, it can be expected that postural control mechanisms are impaired accordingly in these patients. Our aim was to investigate pusher patients' spontaneous postural responses of the non-paretic leg and of the head during passive body tilt. Methods A sideways tilting motion was applied to the trunk of the subject in the roll plane. Stroke patients with pusher syndrome were compared to stroke patients not showing pushing behaviour, patients with acute unilateral vestibular loss, and non brain damaged subjects. Results Compared to all groups without pushing behaviour, the non-paretic leg of the pusher patients showed a constant ipsiversive tilt across the whole tilt range for an amount which was observed in the non-pusher subjects when they were tilted for about 15° into the ipsiversive direction. Conclusion The observation that patients with acute unilateral vestibular loss showed no alterations of leg posture indicates that disturbed vestibular afferences alone are not responsible for the disordered leg responses seen in pusher patients. Our results may suggest that in pusher patients a representation of body orientation is disturbed that drives both conscious perception of body orientation and spontaneous postural adjustment of the non-paretic leg in the roll plane. The investigation of the pusher patients' leg-to-trunk orientation thus could serve as an additional bedside tool to detect pusher syndrome in acute stroke patients. PMID:16928280

  18. 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).

  19. Tuning of Strouhal number for high propulsive efficiency accurately predicts how wingbeat frequency and stroke amplitude relate and scale with size and flight speed in birds.

    PubMed Central

    Nudds, Robert L.; Taylor, Graham K.; Thomas, Adrian L. R.

    2004-01-01

    The wing kinematics of birds vary systematically with body size, but we still, after several decades of research, lack a clear mechanistic understanding of the aerodynamic selection pressures that shape them. Swimming and flying animals have recently been shown to cruise at Strouhal numbers (St) corresponding to a regime of vortex growth and shedding in which the propulsive efficiency of flapping foils peaks (St approximately fA/U, where f is wingbeat frequency, U is cruising speed and A approximately bsin(theta/2) is stroke amplitude, in which b is wingspan and theta is stroke angle). We show that St is a simple and accurate predictor of wingbeat frequency in birds. The Strouhal numbers of cruising birds have converged on the lower end of the range 0.2 < St < 0.4 associated with high propulsive efficiency. Stroke angle scales as theta approximately 67b-0.24, so wingbeat frequency can be predicted as f approximately St.U/bsin(33.5b-0.24), with St0.21 and St0.25 for direct and intermittent fliers, respectively. This simple aerodynamic model predicts wingbeat frequency better than any other relationship proposed to date, explaining 90% of the observed variance in a sample of 60 bird species. Avian wing kinematics therefore appear to have been tuned by natural selection for high aerodynamic efficiency: physical and physiological constraints upon wing kinematics must be reconsidered in this light. PMID:15451698

  20. Mapping the neglected space: gradients of detection revealed by virtual reality.

    PubMed

    Dvorkin, Assaf Y; Bogey, Ross A; Harvey, Richard L; Patton, James L

    2012-02-01

    Spatial neglect affects perception along different dimensions. However, there is limited availability of 3-dimensional (3D) methods that fully map out a patient's volume of deficit, although this could guide clinical management. To test whether patients with neglect exhibit simple contralesional versus complex perceptual deficits and whether deficits are best described using Cartesian (rectangular) or polar coordinates. Seventeen right-hemisphere persons with stroke (8 with a history of neglect) and 9 healthy controls were exposed to a 3D virtual environment. Targets placed in a dense array appeared one at a time in various locations. When tested using rectangular array of targets, subjects in the neglect group exhibited complex asymmetries across several dimensions in both reaction time and target detection rates. Paper-and-pencil tests only detected neglect in 4 of 8 of these patients. When tested using polar array of targets, 2 patients who initially appeared to perform poorly in both left and near space only showed a simple left-side asymmetry that depended almost entirely on the angle from the sagittal plane. A third patient exhibited left neglect irrespective of the arrangements of targets used. An idealized model with pure dependence on the polar angle demonstrated how such deficits could be misconstrued as near neglect if one uses a rectangular array. Such deficits may be poorly detected by paper-and-pencil tests and even by computerized tests that use regular screens. Assessments that incorporate 3D arrangements of targets enable precise mapping of deficient areas and detect subtle forms of neglect whose identification may be relevant to treatment strategies.

  1. Effect of screw position on load transfer in lumbar pedicle screws: A non-idealized finite element analysis

    PubMed Central

    Newcomb, Anna G. U. S.; Baek, Seungwon; Kelly, Brian P.; Crawford, Neil R.

    2016-01-01

    Angled screw insertion has been advocated to enhance fixation strength during posterior spine fixation. Stresses on a pedicle screw and surrounding vertebral bone with different screw angles were studied by finite element analysis during simulated multidirectional loading. Correlations between screw-specific vertebral geometric parameters and stresses were studied. Angulations in both the sagittal and axial planes affected stresses on the cortical and cancellous bones and the screw. Pedicle screws pointing laterally (vs. straight or medially) in the axial plane during superior screw angulation may be advantageous in terms of reducing the risk of both screw loosening and screw breakage. PMID:27454197

  2. Design and fabrication of nosecone for WB-57F aircraft fitted with APQ-102A side looking radar

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The design, fabrication, and testing of a nose cone which included a radome for a NASA WB-57F high altitude natural resources mapping aircraft was reviewed. The plane was fitted with a APQ-102A side looking radar operating at 9.6 GHz. The radar is directed normally to the direction of the flight and downward by a changeable angle, and it is assumed that the axis of the plane will not deviate from this direction by more than + or - 6 deg. The radome is required to subtend an angle of 160 deg centered 30 deg below the left horizon.

  3. Longitudinal decorrelation measures of flow magnitude and event-plane angles in ultrarelativistic nuclear collisions

    NASA Astrophysics Data System (ADS)

    BoŻek, Piotr; Broniowski, Wojciech

    2018-03-01

    We discuss the forward-backward correlations of harmonic flow in Pb +Pb collisions at the CERN Large Hadron Collider, applying standard multibin measures as well as new measures proposed here. We illustrate the methods with hydrodynamic model simulations based on event-by-event initial conditions from the wounded quark model with asymmetric rapidity emission profiles. Within the model, we examine independently the event-plane angle and the flow magnitude decorrelations. We find a specific hierarchy between various flow decorrelation measures and confirm certain factorization relations. We find qualitative agreement of the model and the data from the ATLAS and CMS Collaborations.

  4. Development and preliminary evaluation of a new anatomically based prosthetic alignment method for below-knee prosthesis.

    PubMed

    Tafti, Nahid; Karimlou, Masoud; Mardani, Mohammad Ali; Jafarpisheh, Amir Salar; Aminian, Gholam Reza; Safari, Reza

    2018-04-20

    The objectives of current study were to a) assess similarities and relationships between anatomical landmark-based angles and distances of lower limbs in unilateral transtibial amputees and b) develop and evaluate a new anatomically based static prosthetic alignment method. First sub-study assessed the anthropometrical differences and relationships between the lower limbs in the photographs taken from amputees. Data were analysed via paired t-test and regression analysis. Results show no significant differences in frontal and transverse planes. In the sagittal plane, the anthropometric parameters of the amputated limb were significantly correlated to the corresponding variables of the sound limb. The results served as bases for the development of a new prosthetic alignment method. The method was evaluated on a single subject study. Prosthetic alignment carried out by an experienced prosthetist was compared with such alignment adjusted by an inexperienced prosthetist but with the use of the developed method. In sagittal and frontal planes, the socket angle was tuned with respect to the shin angle, and the position of the prosthetic foot was tuned in relation to the pelvic landmarks. Further study is needed to assess the proposed method on a larger sample of amputees and prosthetists.

  5. Electron gun for a multiple beam klystron with magnetic compression of the electron beams

    DOEpatents

    Ives, R. Lawrence; Tran, Hien T; Bui, Thuc; Attarian, Adam; Tallis, William; David, John; Forstall, Virginia; Andujar, Cynthia; Blach, Noah T; Brown, David B; Gadson, Sean E; Kiley, Erin M; Read, Michael

    2013-10-01

    A multi-beam electron gun provides a plurality N of cathode assemblies comprising a cathode, anode, and focus electrode, each cathode assembly having a local cathode axis and also a central cathode point defined by the intersection of the local cathode axis with the emitting surface of the cathode. Each cathode is arranged with its central point positioned in a plane orthogonal to a device central axis, with each cathode central point an equal distance from the device axis and with an included angle of 360/N between each cathode central point. The local axis of each cathode has a cathode divergence angle with respect to the central axis which is set such that the diverging magnetic field from a solenoidal coil is less than 5 degrees with respect to the projection of the local cathode axis onto a cathode reference plane formed by the device axis and the central cathode point, and the local axis of each cathode is also set such that the angle formed between the cathode reference plane and the local cathode axis results in minimum spiraling in the path of the electron beams in a homogenous magnetic field region of the solenoidal field generator.

  6. Three-Dimensional Geometry of Collagenous Tissues by Second Harmonic Polarimetry.

    PubMed

    Reiser, Karen; Stoller, Patrick; Knoesen, André

    2017-06-01

    Collagen is a biological macromolecule capable of second harmonic generation, allowing label-free detection in tissues; in addition, molecular orientation can be determined from the polarization dependence of the second harmonic signal. Previously we reported that in-plane orientation of collagen fibrils could be determined by modulating the polarization angle of the laser during scanning. We have now extended this method so that out-of-plane orientation angles can be determined at the same time, allowing visualization of the 3-dimensional structure of collagenous tissues. This approach offers advantages compared with other methods for determining out-of-plane orientation. First, the orientation angles are directly calculated from the polarimetry data obtained in a single scan, while other reported methods require data from multiple scans, use of iterative optimization methods, application of fitting algorithms, or extensive post-optical processing. Second, our method does not require highly specialized instrumentation, and thus can be adapted for use in almost any nonlinear optical microscopy setup. It is suitable for both basic and clinical applications. We present three-dimensional images of structurally complex collagenous tissues that illustrate the power of such 3-dimensional analyses to reveal the architecture of biological structures.

  7. Three-Dimensional Geometry of Collagenous Tissues by Second Harmonic Polarimetry

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

    Reiser, Karen; Stoller, Patrick; Knoesen, André

    Collagen is a biological macromolecule capable of second harmonic generation, allowing label-free detection in tissues; in addition, molecular orientation can be determined from the polarization dependence of the second harmonic signal. Previously we reported that in-plane orientation of collagen fibrils could be determined by modulating the polarization angle of the laser during scanning. We have now extended this method so that out-of-plane orientation angles can be determined at the same time, allowing visualization of the 3-dimensional structure of collagenous tissues. This approach offers advantages compared with other methods for determining out-of-plane orientation. First, the orientation angles are directly calculated frommore » the polarimetry data obtained in a single scan, while other reported methods require data from multiple scans, use of iterative optimization methods, application of fitting algorithms, or extensive post-optical processing. Second, our method does not require highly specialized instrumentation, and thus can be adapted for use in almost any nonlinear optical microscopy setup. It is suitable for both basic and clinical applications. We present three-dimensional images of structurally complex collagenous tissues that illustrate the power of such 3-dimensional analyses to reveal the architecture of biological structures.« less

  8. The relationship between the golf swing plane and ball impact characteristics using trajectory ellipse fitting.

    PubMed

    Morrison, Andrew; McGrath, Denise; Wallace, Eric S

    2018-02-01

    The trajectory of the clubhead close to ball impact during the golf swing has previously been shown to be planar. However, the relationship between the plane orientation and the orientation characteristics of the clubhead at ball impact has yet to be defined. Fifty-two male golfers (27 high skilled, 25 intermediate skilled) hit 40 drives each in an indoor biomechanics laboratory. This study successfully fitted the trajectory of the clubhead near impact to an ellipse for each swing for players of different skill levels to help better explain this relationship. Additionally, the eccentricities of the ellipses were investigated for links to skill level. The trajectory of the clubhead was found to fit to an ellipse with RMSE of 1.2 mm. The eccentricity of the ellipse was found to be greater in the high-skilled golfers. The club path and angle of attack generated from the ellipse fitted clubhead trajectory were found to have a normalised bias-corrected RMSE of 2% and 3%, respectively. A set of "rule of thumb" values for the relationship between the club path, angle of attack and delivery plane angle was generated for use by coaches.

  9. Novel Control Scheme of Power Assisted Wheelchair for Preventing Overturn (Part II)-Variable Assistance Ratio Control Based on Estimation of Center-of-Gravity Angle and Phase Plane-

    NASA Astrophysics Data System (ADS)

    Hata, Naoki; Seki, Hirokazu; Koyasu, Yuichi; Hori, Yoichi

    Aged people and disabled people who have difficulty in walking are increasing. As one of mobility support, significance of a power assisted wheelchair which assists driving force using electric motors and spreads their living areas has been enhanced. However, the increased driving force often causes a dangerous overturn of wheelchair. This paper proposes a novel control method to prevent power assisted wheelchair from overturning. The man-wheelchair system can be regarded as an inverse pendulum model when the front wheels are rising. The center-of-gravity (COG) angle of the model is the most important information directly-linked to overturn. Behavior of the system can be analyzed using phase plane as shown in this paper. The COG angle cannot be directly measured using a sensor, therefore, COG observer based on its velocity is proposed. On the basis of the analysis on phase plane, a novel control method with variable assistance ratio to prevent a dangerous overturn is proposed. The effectiveness of the proposed method is verified by the practical experiments on the flat ground and uphill slope.

  10. Three-Dimensional Geometry of Collagenous Tissues by Second Harmonic Polarimetry

    DOE PAGES

    Reiser, Karen; Stoller, Patrick; Knoesen, André

    2017-06-01

    Collagen is a biological macromolecule capable of second harmonic generation, allowing label-free detection in tissues; in addition, molecular orientation can be determined from the polarization dependence of the second harmonic signal. Previously we reported that in-plane orientation of collagen fibrils could be determined by modulating the polarization angle of the laser during scanning. We have now extended this method so that out-of-plane orientation angles can be determined at the same time, allowing visualization of the 3-dimensional structure of collagenous tissues. This approach offers advantages compared with other methods for determining out-of-plane orientation. First, the orientation angles are directly calculated frommore » the polarimetry data obtained in a single scan, while other reported methods require data from multiple scans, use of iterative optimization methods, application of fitting algorithms, or extensive post-optical processing. Second, our method does not require highly specialized instrumentation, and thus can be adapted for use in almost any nonlinear optical microscopy setup. It is suitable for both basic and clinical applications. We present three-dimensional images of structurally complex collagenous tissues that illustrate the power of such 3-dimensional analyses to reveal the architecture of biological structures.« less

  11. Nonuniform fast Fourier transform method for numerical diffraction simulation on tilted planes.

    PubMed

    Xiao, Yu; Tang, Xiahui; Qin, Yingxiong; Peng, Hao; Wang, Wei; Zhong, Lijing

    2016-10-01

    The method, based on the rotation of the angular spectrum in the frequency domain, is generally used for the diffraction simulation between the tilted planes. Due to the rotation of the angular spectrum, the interval between the sampling points in the Fourier domain is not even. For the conventional fast Fourier transform (FFT)-based methods, a spectrum interpolation is needed to get the approximate sampling value on the equidistant sampling points. However, due to the numerical error caused by the spectrum interpolation, the calculation accuracy degrades very quickly as the rotation angle increases. Here, the diffraction propagation between the tilted planes is transformed into a problem about the discrete Fourier transform on the uneven sampling points, which can be evaluated effectively and precisely through the nonuniform fast Fourier transform method (NUFFT). The most important advantage of this method is that the conventional spectrum interpolation is avoided and the high calculation accuracy can be guaranteed for different rotation angles, even when the rotation angle is close to π/2. Also, its calculation efficiency is comparable with that of the conventional FFT-based methods. Numerical examples as well as a discussion about the calculation accuracy and the sampling method are presented.

  12. In-plane and out-of-plane defectivity in thin films of lamellar block copolymers

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

    Mahadevapuram, Nikhila; Mitra, Indranil; Bozhchenko, Alona

    2015-10-29

    We investigate the ordering of poly(styrene-b-methyl methacrylate) (PS-PMMA) lamellar copolymers (periodicity L 0 = 46 nm) confined between a free surface and brushed poly(styrene-r-methyl methacrylate) silicon substrate. The processing temperature was selected to eliminate wetting layers at the top and bottom interfaces, producing approximately neutral boundaries that stabilize perpendicular domain orientations. The PS-PMMA film thickness (t = 0.5L 0–2.5L 0) and brush grafting density (Σ = 0.2–0.6 nm –2) were systematically varied to examine their impacts on in-plane and out-of-plane ordering. Samples were characterized with a combination of high-resolution microscopy, X-ray reflectivity, and grazing-incidence small-angle X-ray scattering. In-plane order atmore » the top of the film (quantified through calculation of orientational correlation lengths) improved with t n, where the exponent n increased from 0.75 to 1 as Σ decreased from 0.6 to 0.2 nm –2. Out-of-plane defects such as tilted domains were detected in all films, and the distribution of domain tilt angles was nearly independent of t and Σ. These studies demonstrate that defectivity in perpendicular lamellar phases is three-dimensional, comprised of in-plane topological defects and out-of-plane domain tilt, with little or no correlation between these two types of disorder. As a result, strong interactions between the block copolymer and underlying substrate may trap both kinds of thermally generated defects.« less

  13. Azimuthal Angle Dependence of HBT Radii in Au+Au Collisions at RHIC-PHENIX

    NASA Astrophysics Data System (ADS)

    Niida, Takafumi

    Measurement of Hanbury-Brown and Twiss (HBT) interferometry with respect to the event plane have been performed in Au+Au collisions at √{sNN} = 200 GeV at PHENIX, which is a unique tool to study the spatial extent of the created matter at final state in heavy ion collisions and the detailed picture of the space-time evolution from the initial state to the final state. The Gaussian source radii was measured for charged pions and kaons with respect to 2nd-order event plane. There was a difference in final eccentricity between both species, which may imply the different freeze-out mechanism by the particle species. The pion source radii was also measured relative to 3rd-order event plane, and the azimuthal angle dependence of the radii was observed, which qualitatively agrees with the recent hydrodynamic calculation and the oscillation may be driven from the triangular flow.

  14. Penetration of sunlight into a canopy - Explicit models based on vertical and horizontal leaf projections

    NASA Technical Reports Server (NTRS)

    Otterman, J.; Brakke, T.

    1986-01-01

    The projections of leaf areas onto a horizontal plane and onto a vertical plane are examined for their utility in characterizing canopies for sunlight penetration (direct beam only) models. These projections exactly specify the penetration if the projections on the principal plane of the normals to the top surfaces of the leaves are in the same quadrant as the sun. Inferring the total leaf area from these projections (and therefore the penetration as a function of the total leaf area) is possible only with a large uncertainty (up to + or - 32 percent) because the projections are a specific measure of the total leaf area only if the leaf angle distribution is known. It is expected that this uncertainty could be reduced to more acceptable levels by making an approximate assessment of whether the zenith angle distribution is that of an extremophile canopy.

  15. User's manual for University of Arizona APART program (Analysis Program - Arizona Radiation Trace)

    NASA Technical Reports Server (NTRS)

    Breault, R. P.

    1975-01-01

    A description and operating instructions for the Analysis Program Arizona Radiation Trace (APART) are given. This is a computer program that is able to efficiently and accurately predict the off-axis rejection characteristics of unwanted stray radiation for complex rotationally symmetric optical systems. The program first determines the critical objects or areas that scatter radiation to the image plane either directly or through imaging elements: this provides the opportunity to modify, if necessary, the design so that the number of critical areas seen by the image plane is reduced or the radiation to these critical areas is minimized. Next, the power distribution reaching the image plane and a sectional power map of all internal surfaces are computed. Angular information is also provided that relates the angle by which the radiation came into a surface to the angle by which the radiation is scattered out of the surface.

  16. Three-dimensional Frankfort horizontal plane for 3D cephalometry: a comparative assessment of conventional versus novel landmarks and horizontal planes.

    PubMed

    Pittayapat, Pisha; Jacobs, Reinhilde; Bornstein, Michael M; Odri, Guillaume A; Lambrichts, Ivo; Willems, Guy; Politis, Constantinus; Olszewski, Raphael

    2018-05-25

    To assess the reproducibility of landmarks in three dimensions that determine the Frankfort horizontal plane (FH) as well as two new landmarks, and to evaluate the angular differences of newly introduced planes to the FH. Three-dimensional (3D) surface models were created from CBCT scans of 26 dry human skulls. Porion (Po), orbitale (Or), internal acoustic foramen (IAF), and zygomatico-maxillary suture (ZyMS) were indicated in the software by three observers twice with a 4-week interval. Angles between two FHs (FH 1: Or-R, Or-L, mid-Po; FH 2: Po-R, Po-L, mid-Or) and between FHs and new planes (Plane 1-6) were measured. Coordinates were exported to a spreadsheet. A statistical analysis was performed to define the landmark reproducibility and 3D angles. Intra- and inter-observer landmark reproducibility showed mean difference more than 1 mm for x-coordinates of all landmarks except IAF. IAF showed significantly better reproducibility than other landmarks (P < 0.0018). The mean angular difference between FH 1 and FH 2 was 0.7 degrees. Plane 3, connecting Or-R, Or-L and mid-IAF, and Plane 4, connecting Po-R, Po-L and mid-ZyMS, both showed an angular difference of less than 1 degree when compared to FHs. This study revealed poor reproducibility of the traditional FH landmarks on the x-axis and good reproducibility of a new landmark tested to replace Po, the IAF. Yet, Or showed superior results compared to ZyMS. The potential of using new horizontal planes was demonstrated. Future studies should focus on identification of a valid alternative for Or and ZyMS and on clinical implementation of the findings.

  17. Cutting Solid Figures by Plane--Analytical Solution and Spreadsheet Implementation

    ERIC Educational Resources Information Center

    Benacka, Jan

    2012-01-01

    In some secondary mathematics curricula, there is a topic called Stereometry that deals with investigating the position and finding the intersection, angle, and distance of lines and planes defined within a prism or pyramid. Coordinate system is not used. The metric tasks are solved using Pythagoras' theorem, trigonometric functions, and sine and…

  18. 16 CFR 1508.11 - Requirements for cutouts.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 1508.11 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT... panel. The axis of the neck shall be horizontal and at right angles to the plane of the panel at the... procedure. The arc through which the head is swung shall be in a vertical plane and shall terminate when the...

  19. 16 CFR 1509.13 - Requirements for cutouts.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 1509.13 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT... side panel. The axis of the neck shall be horizontal and at right angles to the plane of the panel at... procedure. The arc through which the head is swung shall be in a vertical plane and shall terminate when the...

  20. Radiation-Induced Transient Effects in Near Infrared Focal Plane Arrays

    NASA Technical Reports Server (NTRS)

    Reed, Robert A.; Pickel, J.; Marshall, P.; Waczynski, A.; McMurray, R.; Gee, G.; Polidan, E.; Johnson, S.; McKeivey, M.; Ennico, K.; hide

    2004-01-01

    This viewgraph presentation describes a test simulate the transient effects of cosmic ray impacts on near infrared focal plane arrays. The objectives of the test are to: 1) Characterize proton single events as function of energy and angle of incidence; 2) Measure charge spread (crosstalk) to adjacent pixels; 3) Assess transient recovery time.

  1. 1-(3,3-Dichloro-all-yloxy)-2-nitro-benzene.

    PubMed

    Ren, Dong-Mei; Wang, Yong-Yi

    2012-04-01

    In the title compound, C(9)H(7)Cl(2)NO(3), the dihedral angle between the benzene ring and the plane of the nitro group is 50.2 (1)°, and that between the benzene ring and the best plane through the dichloro-allyl fragment is 40.1 (1)°.

  2. Study on the propagation properties of laser in aerosol based on Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Leng, Kun; Wu, Wenyuan; Zhang, Xi; Gong, Yanchun; Yang, Yuntao

    2018-02-01

    When laser propagate in the atmosphere, due to aerosol scattering and absorption, laser energy will continue to decline, affecting the effectiveness of the laser effect. Based on the Monte Carlo method, the relationship between the photon spatial energy distributions of the laser wavelengths of 10.6μm in marine, sand-type, water-soluble and soot aerosols ,and the propagation distance, visibility and the divergence angle were studied. The results show that for 10.6μm laser, the maximum number of attenuation of photons arriving at the receiving plane is sand-type aerosol, the minimal attenuation is water soluble aerosol; as the propagation distance increases, the number of photons arriving at the receiving plane decreases; as the visibility increases, the number of photons arriving at the receiving plane increases rapidly and then stabilizes; in the above cases, the photon energy distribution does not deviated from the Gaussian distribution; as the divergence angle increases, the number of photons arriving at the receiving plane is almost unchanged, but the photon energy distribution gradually deviates from the Gaussian distribution.

  3. Numerical modelling of orthogonal cutting: application to woodworking with a bench plane.

    PubMed

    Nairn, John A

    2016-06-06

    A numerical model for orthogonal cutting using the material point method was applied to woodcutting using a bench plane. The cutting process was modelled by accounting for surface energy associated with wood fracture toughness for crack growth parallel to the grain. By using damping to deal with dynamic crack propagation and modelling all contact between wood and the plane, simulations could initiate chip formation and proceed into steady-state chip propagation including chip curling. Once steady-state conditions were achieved, the cutting forces became constant and could be determined as a function of various simulation variables. The modelling details included a cutting tool, the tool's rake and grinding angles, a chip breaker, a base plate and a mouth opening between the base plate and the tool. The wood was modelled as an anisotropic elastic-plastic material. The simulations were verified by comparison to an analytical model and then used to conduct virtual experiments on wood planing. The virtual experiments showed interactions between depth of cut, chip breaker location and mouth opening. Additional simulations investigated the role of tool grinding angle, tool sharpness and friction.

  4. The Star Wars Scroll Illusion.

    PubMed

    Shapiro, Arthur G

    2015-10-01

    The Star Wars Scroll Illusion is a dynamic version of the Leaning Tower Illusion. When two copies of a Star-Wars-like scrolling text are placed side by side (with separate vanishing points), the two scrolls appear to head in different directions even though they are physically parallel in the picture plane. Variations of the illusion are shown with one vanishing point, as well as from an inverted perspective where the scrolls appear to originate in the distance. The demos highlight the conflict between the physical lines in the picture plane and perspective interpretation: With two perspective points, the scrolling texts are parallel to each other in the picture plane but not in perspective interpretation; with one perspective point, the texts are not parallel to each other in the picture plane but are parallel to each other in perspective interpretation. The size of the effect is linearly related to the angle of rotation of the scrolls into the third dimension; the Scroll Illusion is stronger than the Leaning Tower Illusion for rotation angles between 35° and 90°. There is no effect of motion per se on the strength of the illusion.

  5. An adaptive guidance algorithm for an aerodynamically assisted orbital plane change maneuver. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Blissit, J. A.

    1986-01-01

    Using analysis results from the post trajectory optimization program, an adaptive guidance algorithm is developed to compensate for density, aerodynamic and thrust perturbations during an atmospheric orbital plane change maneuver. The maneuver offers increased mission flexibility along with potential fuel savings for future reentry vehicles. Although designed to guide a proposed NASA Entry Research Vehicle, the algorithm is sufficiently generic for a range of future entry vehicles. The plane change analysis provides insight suggesting a straight-forward algorithm based on an optimized nominal command profile. Bank angle, angle of attack, and engine thrust level, ignition and cutoff times are modulated to adjust the vehicle's trajectory to achieve the desired end-conditions. A performance evaluation of the scheme demonstrates a capability to guide to within 0.05 degrees of the desired plane change and five nautical miles of the desired apogee altitude while maintaining heating constraints. The algorithm is tested under off-nominal conditions of + or -30% density biases, two density profile models, + or -15% aerodynamic uncertainty, and a 33% thrust loss and for various combinations of these conditions.

  6. Ultra-thin ZnSe: Anisotropic and flexible crystal structure

    NASA Astrophysics Data System (ADS)

    Bacaksiz, C.; Senger, R. T.; Sahin, H.

    2017-07-01

    By performing density functional theory-based calculations, we investigate the structural, electronic, and mechanical properties of the thinnest ever ZnSe crystal [11]. The vibrational spectrum analysis reveals that the monolayer ZnSe is dynamically stable and has flexible nature with its soft phonon modes. In addition, a direct electronic band gap is found at the gamma point for the monolayer structure of ZnSe. We also elucidate that the monolayer ZnSe has angle dependent in-plane elastic parameters. In particular, the in-plane stiffness values are found to be 2.07 and 6.89 N/m for the arm-chair and zig-zag directions, respectively. The angle dependency is also valid for the Poisson ratio of the monolayer ZnSe. More significantly, the in-plane stiffness of the monolayer ZnSe is the one-tenth of Young modulus of bulk zb-ZnSe which indicates that the monolayer ZnSe is a quite flexible single layer crystal. With its flexible nature and in-plane anisotropic mechanical properties, the monolayer ZnSe is a good candidate for nanoscale mechanical applications.

  7. Test technology on divergence angle of laser range finder based on CCD imaging fusion

    NASA Astrophysics Data System (ADS)

    Shi, Sheng-bing; Chen, Zhen-xing; Lv, Yao

    2016-09-01

    Laser range finder has been equipped with all kinds of weapons, such as tank, ship, plane and so on, is important component of fire control system. Divergence angle is important performance and incarnation of horizontal resolving power for laser range finder, is necessary appraised test item in appraisal test. In this paper, based on high accuracy test on divergence angle of laser range finder, divergence angle test system is designed based on CCD imaging, divergence angle of laser range finder is acquired through fusion technology for different attenuation imaging, problem that CCD characteristic influences divergence angle test is solved.

  8. Bonded half planes containing an arbitrarily oriented crack

    NASA Technical Reports Server (NTRS)

    Erdogan, F.; Aksogan, O.

    1973-01-01

    The plane elastostatic problem for two bonded half planes containing an arbitrarily oriented crack in the neighborhood of the interface is considered. Using Mellin transforms, the problem is formulated as a system of singular integral equations. The equations are solved for various crack orientations, material combinations, and external loads. The numerical results given include the stress intensity factors, tHe strain energy release rates, and tHe probable cleavage angles giving the direction of crack propagation.

  9. Contract W911NF-07-1-0205 (University of Central Florida)

    DTIC Science & Technology

    2011-01-19

    inhomogeneous material using CDA, the modeling cube can be replicated in 2 dimensions, (x-y plane ) with some periodicity specified by the initial...light. We would like to consider the situation where we have a plane wave with some arbitrary angle of incidence on the slab of inhomogeneous material...each monolayer corresponding to the repetition of each plane . Unfortunately, the lattice sums over n and m in real space does not converge. However

  10. Detection for flatness of large surface based on structured light

    NASA Astrophysics Data System (ADS)

    He, Wenyan; Cao, Xuedong; Long, Kuang; Peng, Zhang

    2016-09-01

    In order to get flatness of a large plane, this paper set up a measurement system, composed by Line Structured Light, imaging system, CCD, etc. Line Structured Light transmits parallel fringes at a proper angle onto the plane which is measured; the imaging system and CCD locate above the plane to catch the fringes. When the plane is perfect, CCD will catch straight fringes; however, the real plane is not perfect; according to the theory of projection, the fringes caught by CCD will be distorted by convex and concave. Extract the center of line fringes to obtain the distortion of the fringe, according to the functional relationship between the distortion of fringes and the height which is measured, then we will get flatness of the entire surface. Data from experiment approached the analysis of theory. In the simulation, the vertical resolution is 0.0075 mm per pixel when measuring a plane of 400mm×400mm, choosing the size of CCD 4096×4096, at the angle 85°. Helped by sub-pixel, the precision will get the level of submicron. There are two obvious advantages: method of surface sampling can increase the efficiency for auto-repairing of machines; considering the center of fringe is required mainly in this system, as a consequence, there is no serious demand for back light.

  11. Anticipatory postural adjustments during sitting reach movement in post-stroke subjects.

    PubMed

    Pereira, Soraia; Silva, Cláudia C; Ferreira, Sílvia; Silva, Cláudia; Oliveira, Nuno; Santos, Rubim; Vilas-Boas, John P; Correia, Miguel V

    2014-02-01

    The study assessed the effect of velocity of arm movement on anticipatory postural adjustments (APAs) generation in the contralateral and ipsilateral muscles of individuals with stroke in seating. Ten healthy and eight post-stroke subjects were studied in sitting. The task consisted in reaching an object placed at scapular plane and mid-sternum height at self-selected and fast velocities. Electromyography was recorded from anterior deltoid (AD), upper (UT) and lower trapezius (LT) and latissimus dorsi (LD). While kinematic analysis was used to assess peak velocity and trunk displacement. Differences were found between the timing of APAs on ipsi and contralateral LD and LT in both movement speeds and in ipsilateral UT during movement of the non-affected arm at a self-selected velocity. A delay on the contralateral LD to reach movement with the non-affected arm at fast velocity was also observed. The trunk displacement was greater in post-stroke subjects. Individuals with stroke demonstrated a delay of APAs in the muscles on both sides of the body compared to healthy subjects. The delay was observed during performance of the reaching task with the fast and self-selected velocity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. The evidential value of distorted and rectified digital images in footwear imprint examination.

    PubMed

    Shor, Yaron; Chaikovsky, Alan; Tsach, Tsadok

    2006-06-27

    The procedure for forensic photography requires that the film plane be parallel to the taken image. Another procedure must be used when the print is located on reflecting surfaces such as vehicles, or faint marks on porous surfaces. Examination was made of the evidential value of footprint images received from the scene or taken deliberately at an angle out of proper perspective (i.e., the lens axis is not perpendicular to the target plane). An artificial target was prepared and photographed from several lens axis angles ranging from 10 degrees to 85 degrees to the perpendicular, and then rectified using the Adobe Photoshop Version 7.0. It was found that at angles less than 40 degrees , the shape and location of all the individual characteristics were similar enough in comparison to the original image. In images taken at higher angles, the original image could not be adequately restored. The full potential of this image, therefore, could not be achieved after rectification. The results of this study show that the images of a footprint taken at an angle less than 40 degrees , preserve the evidential value of the unique characteristics.

  13. Formation mechanisms for the dominant kinks with different angles in InP nanowires.

    PubMed

    Zhang, Minghuan; Wang, Fengyun; Wang, Chao; Wang, Yiqian; Yip, SenPo; Ho, Johnny C

    2014-01-01

    The morphologies and microstructures of kinked InP nanowires (NWs) prepared by solid-source chemical vapor deposition method were examined using scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). Statistical analysis and structural characterization reveal that four different kinds of kinks are dominant in the grown InP NWs with a bending angle of approximately 70°, 90°, 110°, and 170°, respectively. The formation mechanisms of these kinks are discussed. Specifically, the existence of kinks with bending angles of approximately 70° and 110° are mainly attributed to the occurrence of stacking faults and nanotwins in the NWs, which could easily form by the glide of {111} planes, while approximately 90° kinks result from the local amorphorization of InP NWs. Also, approximately 170° kinks are mainly caused by small-angle boundaries, where the insertion of extra atomic planes could make the NWs slightly bent. In addition, multiple kinks with various angles are also observed. Importantly, all these results are beneficial to understand the formation mechanisms of kinks in compound semiconductor NWs, which could guide the design of nanostructured materials, morphologies, microstructures, and/or enhanced mechanical properties.

  14. Formation mechanisms for the dominant kinks with different angles in InP nanowires

    PubMed Central

    2014-01-01

    The morphologies and microstructures of kinked InP nanowires (NWs) prepared by solid-source chemical vapor deposition method were examined using scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). Statistical analysis and structural characterization reveal that four different kinds of kinks are dominant in the grown InP NWs with a bending angle of approximately 70°, 90°, 110°, and 170°, respectively. The formation mechanisms of these kinks are discussed. Specifically, the existence of kinks with bending angles of approximately 70° and 110° are mainly attributed to the occurrence of stacking faults and nanotwins in the NWs, which could easily form by the glide of {111} planes, while approximately 90° kinks result from the local amorphorization of InP NWs. Also, approximately 170° kinks are mainly caused by small-angle boundaries, where the insertion of extra atomic planes could make the NWs slightly bent. In addition, multiple kinks with various angles are also observed. Importantly, all these results are beneficial to understand the formation mechanisms of kinks in compound semiconductor NWs, which could guide the design of nanostructured materials, morphologies, microstructures, and/or enhanced mechanical properties. PMID:24910572

  15. Rapid Parametric Mapping of the Longitudinal Relaxation Time T1 Using Two-Dimensional Variable Flip Angle Magnetic Resonance Imaging at 1.5 Tesla, 3 Tesla, and 7 Tesla

    PubMed Central

    Dieringer, Matthias A.; Deimling, Michael; Santoro, Davide; Wuerfel, Jens; Madai, Vince I.; Sobesky, Jan; von Knobelsdorff-Brenkenhoff, Florian; Schulz-Menger, Jeanette; Niendorf, Thoralf

    2014-01-01

    Introduction Visual but subjective reading of longitudinal relaxation time (T1) weighted magnetic resonance images is commonly used for the detection of brain pathologies. For this non-quantitative measure, diagnostic quality depends on hardware configuration, imaging parameters, radio frequency transmission field (B1+) uniformity, as well as observer experience. Parametric quantification of the tissue T1 relaxation parameter offsets the propensity for these effects, but is typically time consuming. For this reason, this study examines the feasibility of rapid 2D T1 quantification using a variable flip angles (VFA) approach at magnetic field strengths of 1.5 Tesla, 3 Tesla, and 7 Tesla. These efforts include validation in phantom experiments and application for brain T1 mapping. Methods T1 quantification included simulations of the Bloch equations to correct for slice profile imperfections, and a correction for B1+. Fast gradient echo acquisitions were conducted using three adjusted flip angles for the proposed T1 quantification approach that was benchmarked against slice profile uncorrected 2D VFA and an inversion-recovery spin-echo based reference method. Brain T1 mapping was performed in six healthy subjects, one multiple sclerosis patient, and one stroke patient. Results Phantom experiments showed a mean T1 estimation error of (-63±1.5)% for slice profile uncorrected 2D VFA and (0.2±1.4)% for the proposed approach compared to the reference method. Scan time for single slice T1 mapping including B1+ mapping could be reduced to 5 seconds using an in-plane resolution of (2×2) mm2, which equals a scan time reduction of more than 99% compared to the reference method. Conclusion Our results demonstrate that rapid 2D T1 quantification using a variable flip angle approach is feasible at 1.5T/3T/7T. It represents a valuable alternative for rapid T1 mapping due to the gain in speed versus conventional approaches. This progress may serve to enhance the capabilities of parametric MR based lesion detection and brain tissue characterization. PMID:24621588

  16. Rapid parametric mapping of the longitudinal relaxation time T1 using two-dimensional variable flip angle magnetic resonance imaging at 1.5 Tesla, 3 Tesla, and 7 Tesla.

    PubMed

    Dieringer, Matthias A; Deimling, Michael; Santoro, Davide; Wuerfel, Jens; Madai, Vince I; Sobesky, Jan; von Knobelsdorff-Brenkenhoff, Florian; Schulz-Menger, Jeanette; Niendorf, Thoralf

    2014-01-01

    Visual but subjective reading of longitudinal relaxation time (T1) weighted magnetic resonance images is commonly used for the detection of brain pathologies. For this non-quantitative measure, diagnostic quality depends on hardware configuration, imaging parameters, radio frequency transmission field (B1+) uniformity, as well as observer experience. Parametric quantification of the tissue T1 relaxation parameter offsets the propensity for these effects, but is typically time consuming. For this reason, this study examines the feasibility of rapid 2D T1 quantification using a variable flip angles (VFA) approach at magnetic field strengths of 1.5 Tesla, 3 Tesla, and 7 Tesla. These efforts include validation in phantom experiments and application for brain T1 mapping. T1 quantification included simulations of the Bloch equations to correct for slice profile imperfections, and a correction for B1+. Fast gradient echo acquisitions were conducted using three adjusted flip angles for the proposed T1 quantification approach that was benchmarked against slice profile uncorrected 2D VFA and an inversion-recovery spin-echo based reference method. Brain T1 mapping was performed in six healthy subjects, one multiple sclerosis patient, and one stroke patient. Phantom experiments showed a mean T1 estimation error of (-63±1.5)% for slice profile uncorrected 2D VFA and (0.2±1.4)% for the proposed approach compared to the reference method. Scan time for single slice T1 mapping including B1+ mapping could be reduced to 5 seconds using an in-plane resolution of (2×2) mm2, which equals a scan time reduction of more than 99% compared to the reference method. Our results demonstrate that rapid 2D T1 quantification using a variable flip angle approach is feasible at 1.5T/3T/7T. It represents a valuable alternative for rapid T1 mapping due to the gain in speed versus conventional approaches. This progress may serve to enhance the capabilities of parametric MR based lesion detection and brain tissue characterization.

  17. A simple analytical aerodynamic model of Langley Winged-Cone Aerospace Plane concept

    NASA Technical Reports Server (NTRS)

    Pamadi, Bandu N.

    1994-01-01

    A simple three DOF analytical aerodynamic model of the Langley Winged-Coned Aerospace Plane concept is presented in a form suitable for simulation, trajectory optimization, and guidance and control studies. The analytical model is especially suitable for methods based on variational calculus. Analytical expressions are presented for lift, drag, and pitching moment coefficients from subsonic to hypersonic Mach numbers and angles of attack up to +/- 20 deg. This analytical model has break points at Mach numbers of 1.0, 1.4, 4.0, and 6.0. Across these Mach number break points, the lift, drag, and pitching moment coefficients are made continuous but their derivatives are not. There are no break points in angle of attack. The effect of control surface deflection is not considered. The present analytical model compares well with the APAS calculations and wind tunnel test data for most angles of attack and Mach numbers.

  18. Flow-field surveys on the windward side of the NASA 040A space shuttle orbiter at 31 deg angle of attack and Mach 20 in helium

    NASA Technical Reports Server (NTRS)

    Ashby, G. C., Jr.; Helms, V. T., III

    1977-01-01

    Pitot pressure and flow angle distributions in the windward flow field of the NASA 040A space shuttle orbiter configuration and surface pressures were measured, at a Mach number of 20 and an angle of attack of 31 deg. The free stream Reynolds number, based on model length, was 5.39 x 10 to the 6th power. Results show that cores of high pitot pressure, which are related to the body-shock-wing-shock intersections, occur on the windward plane of symmetry in the vicinity of the wing-body junction and near midspan on the wing. Theoretical estimates of the flow field pitot pressures show that conical flow values for the windward plane of symmetry surface are representative of the average level over the entire lower surface.

  19. N-(1-Allyl-1H-indazol-5-yl)-4-methyl-benzene-sulfonamide.

    PubMed

    Chicha, Hakima; Rakib, El Mostapha; Abderrafia, Hafid; Saadi, Mohamed; El Ammari, Lahcen

    2013-11-30

    The asymmetric unit of the title compound, C17H17N3O2S, contains two independent mol-ecules linked by an N-H⋯O hydrogen bond. The mol-ecules show different conformations. In the first mol-ecule, the fused five- and six-membered ring system is almost perpendicular to the plane through the atoms forming the allyl group, as indicated by the dihedral angle of 85.1 (4)°. The dihedral angle with the methyl-benzene-sulfonamide group is 78.8 (1)°. On the other hand, in the second mol-ecule, the dihedral angles between the indazole plane and the allyl and methyl-benzene-sulfonamide groups are 80.3 (3) and 41.5 (1)°, respectively. In the crystal, mol-ecules are further linked by N-H⋯N and C-H⋯O hydrogen bonds, forming a three-dimensional network.

  20. Retrograde lag screw placement in anterior acetabular column with regard to the anterior pelvic plane and midsagittal plane -- virtual mapping of 260 three-dimensional hemipelvises for quantitative anatomic analysis.

    PubMed

    Ochs, Bjoern Gunnar; Stuby, Fabian Maria; Ateschrang, Atesch; Stoeckle, Ulrich; Gonser, Christoph Emanuel

    2014-10-01

    Percutaneous screw placement can be used for minimally invasive treatment of none or minimally displaced fractures of the anterior column. The complex pelvic geometry can pose a major challenge even for experienced surgeons. The present study examined the preformed bone stock of the anterior column in 260 hemipelvises (130 male and 130 female). Screws were virtually implanted using iPlan(®) CMF (BrainLAB AG, Feldkirchen, Germany); the maximal implant length and the maximal implant diameter were assessed. The study showed, that 6.5mm can generally be used in men; in women however individual planning is essential in regard to the maximal implant diameter since we found that in 15.4% of women, screws with a diameter less than 6.5mm were necessary. The virtual analysis of the preformed bone stock corridor of the anterior column showed two constrictions of crucial clinical importance. These can be found after 18% and 55% (men) respectively 16% and 55% (women) measured from the entry point along the axis of the implant. The entry point of the retrograde anterior column screw in our collective was located lateral of tuberculum pubicum at the level of the superior-medial margin of foramen obturatum. In female patients, the entry point was located significantly more lateral of symphysis and closer to the cranial margin of ramus superior ossis pubis. The mean angle between the screw trajectory and the anterior pelvic plane in sagittal section was 31.6 ± 5.5°, the mean angle between the screw trajectory and the midsagittal plane in axial section was 55.9 ± 4.6° and the mean angle between the screw trajectory and the midsagittal plane in coronal section was 42.1 ± 3.9° with no significant deviation between both sexes. The individual angles formed by the screw trajectory and the anterior pelvic and midsagittal plane are independent from anthropometric parameters sex, age, body length and weight. Therefore, they can be used for orientation in lag screw placement keeping in mind that the entry point differs in both sexes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. 3-D Vector Flow Estimation With Row-Column-Addressed Arrays.

    PubMed

    Holbek, Simon; Christiansen, Thomas Lehrmann; Stuart, Matthias Bo; Beers, Christopher; Thomsen, Erik Vilain; Jensen, Jorgen Arendt

    2016-11-01

    Simulation and experimental results from 3-D vector flow estimations for a 62 + 62 2-D row-column (RC) array with integrated apodization are presented. A method for implementing a 3-D transverse oscillation (TO) velocity estimator on a 3-MHz RC array is developed and validated. First, a parametric simulation study is conducted, where flow direction, ensemble length, number of pulse cycles, steering angles, transmit/receive apodization, and TO apodization profiles and spacing are varied, to find the optimal parameter configuration. The performance of the estimator is evaluated with respect to relative mean bias ~B and mean standard deviation ~σ . Second, the optimal parameter configuration is implemented on the prototype RC probe connected to the experimental ultrasound scanner SARUS. Results from measurements conducted in a flow-rig system containing a constant laminar flow and a straight-vessel phantom with a pulsating flow are presented. Both an M-mode and a steered transmit sequence are applied. The 3-D vector flow is estimated in the flow rig for four representative flow directions. In the setup with 90° beam-to-flow angle, the relative mean bias across the entire velocity profile is (-4.7, -0.9, 0.4)% with a relative standard deviation of (8.7, 5.1, 0.8)% for ( v x , v y , v z ). The estimated peak velocity is 48.5 ± 3 cm/s giving a -3% bias. The out-of-plane velocity component perpendicular to the cross section is used to estimate volumetric flow rates in the flow rig at a 90° beam-to-flow angle. The estimated mean flow rate in this setup is 91.2 ± 3.1 L/h corresponding to a bias of -11.1%. In a pulsating flow setup, flow rate measured during five cycles is 2.3 ± 0.1 mL/stroke giving a negative 9.7% bias. It is concluded that accurate 3-D vector flow estimation can be obtained using a 2-D RC-addressed array.

  2. Validity of measurement of shear modulus by ultrasound shear wave elastography in human pennate muscle.

    PubMed

    Miyamoto, Naokazu; Hirata, Kosuke; Kanehisa, Hiroaki; Yoshitake, Yasuhide

    2015-01-01

    Ultrasound shear wave elastography is becoming a valuable tool for measuring mechanical properties of individual muscles. Since ultrasound shear wave elastography measures shear modulus along the principal axis of the probe (i.e., along the transverse axis of the imaging plane), the measured shear modulus most accurately represents the mechanical property of the muscle along the fascicle direction when the probe's principal axis is parallel to the fascicle direction in the plane of the ultrasound image. However, it is unclear how the measured shear modulus is affected by the probe angle relative to the fascicle direction in the same plane. The purpose of the present study was therefore to examine whether the angle between the principal axis of the probe and the fascicle direction in the same plane affects the measured shear modulus. Shear modulus in seven specially-designed tissue-mimicking phantoms, and in eleven human in-vivo biceps brachii and medial gastrocnemius were determined by using ultrasound shear wave elastography. The probe was positioned parallel or 20° obliquely to the fascicle across the B-mode images. The reproducibility of shear modulus measurements was high for both parallel and oblique conditions. Although there was a significant effect of the probe angle relative to the fascicle on the shear modulus in human experiment, the magnitude was negligibly small. These findings indicate that the ultrasound shear wave elastography is a valid tool for evaluating the mechanical property of pennate muscles along the fascicle direction.

  3. Atmospheric effects on radiometry from zenith of a plane with dark vertical protrusions

    NASA Technical Reports Server (NTRS)

    Otterman, J.

    1983-01-01

    Effects of an optically thin plane-parallel scattering atmosphere on radiometric imaging from the zenith of a specific surface-type are analyzed. The surface model was previously developed to describe arid steppe, where the sparse vegetation forms dark vertical protrusions from the bright soil-plane. The analysis is in terms of the surface reflectivity to the zenith r sub p for the direct beam, which is formulated as r sub p = r sub i exp (-s tan theta sub 0), where v sub i is the Lambert law reflectivity of the soil, the protrusions parameters s is the projection on a vertical plane of protrusions per unit area and theta sub 0 is the zenith angle. The surface reflectivity r sub p is approximately equal to that for the global irradiance (which is directly measured in the field) only for a narrow range of the solar zenith angles. The effects of the atmosphere when imaging large uniform areas of this type are comparable to those in imaging a Lambert surface with a reflectivity r sub p. Thus, the effects can be approximated by those in the case of a dark Lambert surface (analyzed previously), inasmuch as r sub p is smaller than the soil reflectivity r sub i for any off-zenith illumination. The surface becomes effectively darker with increasing solar zenith angle. Adjacency effects of a reflection from one area and scattering in the instantaneous field of view (object pixel) are analyzed as cross radiance and cross irradiance.

  4. Retrieval of Aerosol Phase Function and Polarized Phase Function from Polarization of Skylight for Different Observation Geometries

    NASA Astrophysics Data System (ADS)

    Li, L.; Qie, L. L.; Xu, H.; Li, Z. Q.

    2018-04-01

    The phase function and polarized phase function are important optical parameters, which describe scattering properties of atmospheric aerosol particles. Polarization of skylight induced by the scattering processes is sensitive to the scattering properties of aerosols. The Stokes parameters I, Q, U and the polarized radiance Lp of skylight measured by the CIMEL dual-polar sun-sky radiometer CE318- DP can be use to retrieve the phase function and polarized phase function, respectively. Two different observation geometries (i.e., the principal plane and almucantar) are preformed by the CE318-DP to detect skylight polarization. Polarization of skylight depends on the illumination and observation geometries. For the same solar zenith angle, retrievals of the phase function and the polarized phase function are still affected by the observation geometry. The performance of the retrieval algorithm for the principal plane and almucantar observation geometries was assessed by the numerical experiments at two typical high and low sun's positions (i.e. solar zenith angles are equal to 45° and 65°). Comparing the results for the principal plane and almucantar geometries, it is recommended to utilize the principal plane observations to retrieve the phase function when the solar zenith angle is small. The Stokes parameter U and the polarized radiance Lp from the almucantar observations are suggested to retrieve the polarized phase function, especially for short wavelength channels (e.g., 440 and 500 nm).

  5. Sauter-Schwinger pair creation dynamically assisted by a plane wave

    NASA Astrophysics Data System (ADS)

    Torgrimsson, Greger; Schneider, Christian; Schützhold, Ralf

    2018-05-01

    We study electron-positron pair creation by a strong and constant electric field superimposed with a weaker transversal plane wave which is incident perpendicularly (or under some angle). Comparing the fully nonperturbative approach based on the world-line instanton method with a perturbative expansion into powers of the strength of the weaker plane wave, we find good agreement—provided that the latter is carried out to sufficiently high orders. As usual for the dynamically assisted Sauter-Schwinger effect, the additional plane wave induces an exponential enhancement of the pair-creation probability if the combined Keldysh parameter exceeds a certain threshold.

  6. Computational Fluid Dynamics Study of Swimmer's Hand Velocity, Orientation, and Shape: Contributions to Hydrodynamics

    PubMed Central

    Bilinauskaite, Milda; Mantha, Vishveshwar Rajendra; Rouboa, Abel Ilah; Ziliukas, Pranas; Silva, Antonio Jose

    2013-01-01

    The aim of this paper is to determine the hydrodynamic characteristics of swimmer's scanned hand models for various combinations of both the angle of attack and the sweepback angle and shape and velocity of swimmer's hand, simulating separate underwater arm stroke phases of freestyle (front crawl) swimming. Four realistic 3D models of swimmer's hand corresponding to different combinations of separated/closed fingers positions were used to simulate different underwater front crawl phases. The fluid flow was simulated using FLUENT (ANSYS, PA, USA). Drag force and drag coefficient were calculated using (computational fluid dynamics) CFD in steady state. Results showed that the drag force and coefficient varied at the different flow velocities on all shapes of the hand and variation was observed for different hand positions corresponding to different stroke phases. The models of the hand with thumb adducted and abducted generated the highest drag forces and drag coefficients. The current study suggests that the realistic variation of both the orientation angles influenced higher values of drag, lift, and resultant coefficients and forces. To augment resultant force, which affects swimmer's propulsion, the swimmer should concentrate in effectively optimising achievable hand areas during crucial propulsive phases. PMID:23691493

  7. Kinematic characteristics of the stroke and orientation of the hand during front crawl resisted swimming.

    PubMed

    Gourgoulis, Vassilios; Antoniou, Panagiotis; Aggeloussis, Nikolaos; Mavridis, Georgios; Kasimatis, Panagiotis; Vezos, Nikolaos; Boli, Alexia; Mavromatis, Georgios

    2010-09-01

    The aim of this study was to examine the acute effect of front crawl sprint resisted swimming with different added resistances on the kinematic characteristics of the stroke and the orientation of the hand. Ten female swimmers swam four maximal trials (25 m) with small, moderate, large, and no added resistance respectively. Four camcorders were used to record the underwater motion of the right hand and digitizing was undertaken using the Ariel Performance Analysis System. Stroke rate, the stroke length, and mean swimming velocity were significantly decreased, whereas the total duration of the stroke and the relative duration of the pull and push phases were significantly increased during resisted swimming. The increase in the total duration of the stroke was accompanied by an increase in absolute pull length, while no alterations were observed in relative pull length or medial-lateral displacements of the hand. Moreover, the mean resultant velocity of the hand, as well as the pitch and the sweepback angles of the hand were not modified. In conclusion, resisted swimming appears to be a specific form of training, at least regarding its acute effect, although long-term effects should be investigated further.

  8. Quantitative assessment of joint position sense recovery in subacute stroke patients: a pilot study.

    PubMed

    Kattenstroth, Jan-Christoph; Kalisch, Tobias; Kowalewski, Rebecca; Tegenthoff, Martin; Dinse, Hubert R

    2013-11-01

    To assess joint position sense performance in subacute stroke patients using a novel quantitative assessment. Proof-of-principle pilot study with a group of subacute stroke patients. Assessment at baseline and after 2 weeks of intervention. Additional data for a healthy age-matched control group. Ten subacute stroke patients (aged 65.41 years (standard deviation 2.5), 4 females, 2.3 weeks (standard deviation 0.2)) post-stroke receiving in-patient standard rehabilitation and repetitive electrical stimulation of the affected hand. Joint position sense was assessed based on the ability of correctly perceiving the opening angles of the finger joints. Patients had to report size differences of polystyrene balls of various sizes, whilst the balls were enclosed simultaneously by the affected and the non-affected hands. A total of 21 pairwise size comparisons was used to quantify joint position performance. After 2 weeks of therapeutic intervention a significant improvement in joint position sense performance was observed; however, the performance level was still below that of a healthy control group. The results indicate high feasibility and sensitivity of the joint position test in subacute stroke patients. Testing allowed quantification of both the deficit and the rehabilitation outcome.

  9. Lightning spectra at 100,000 fps

    NASA Astrophysics Data System (ADS)

    McHarg, M. G.; Harley, J.; Haaland, R. K.; Edens, H. E.; Stenbaek-Nielsen, H.

    2016-12-01

    A fundamental understanding of lightning can be inferred from the spectral emissions resulting from the leader and return stroke channel. We examine an event recorded at 00:58:07 on 19 July 2015 at Langmuir Laboratory. We recorded lightning spectra using a 100 line per mm grating in front of a Phantom V2010 camera with an 85mm Nikon lens recording at 100,000 frames per second. Coarse resolution spectra (approximately 5nm resolution) are produced from approximately 400 nm to 800 nm for each frame. Electric field data from the Langmuir Electric Field Array for the 03:19:19 event show 10 V/m changes in the electric field associated with multiple return strokes visible in the spectral data. We used the spectral data to compare temperatures at the top, middle and bottom of the lightning channel. Lightning Mapping Array data at Langmuir for the 00:58:07 event show a complex flash extending 10 km in the East-West plane and 6 km in the North-South plane. The imagery data imply that this is a bolt-from-the-blue event.

  10. Equipment Development for Automatic Anthropometric Measurements

    NASA Technical Reports Server (NTRS)

    Cater, J. P.; Oakey, W. E.

    1978-01-01

    An automated procedure for measuring and recording the anthropometric active angles is presented. The small portable system consists of a microprocessor controlled video data acquisition system which measures single plane active angles using television video techniques and provides the measured data on sponsored-specified preformatted data sheets. This system, using only a single video camera, observes the end limits of the movement of a pair of separated lamps and calculates the vector angle between the extreme positions.

  11. Mechanical design and performance evaluation for plane grating monochromator in a soft X-ray microscopy beamline at SSRF.

    PubMed

    Gong, Xuepeng; Lu, Qipeng

    2015-01-01

    A new monochromator is designed to develop a high performance soft X-ray microscopy beamline at Shanghai Synchrotron Radiation Facility (SSRF). But owing to its high resolving power and high accurate spectrum output, there exist many technical difficulties. In the paper presented, as two primary design targets for the monochromator, theoretical energy resolution and photon flux of the beamline are calculated. For wavelength scanning mechanism, primary factors affecting the rotary angle errors are presented, and the measuring results are 0.15'' and 0.17'' for plane mirror and plane grating, which means that it is possible to provide sufficient scanning precision to specific wavelength. For plane grating switching mechanism, the repeatabilities of roll, yaw and pitch angles are 0.08'', 0.12'' and 0.05'', which can guarantee the high accurate switch of the plane grating effectively. After debugging, the repeatability of light spot drift reaches to 0.7'', which further improves the performance of the monochromator. The commissioning results show that the energy resolving power is higher than 10000 at Ar L-edge, the photon flux is higher than 1 × 108 photons/sec/200 mA, and the spatial resolution is better than 30 nm, demonstrating that the monochromator performs very well and reaches theoretical predictions.

  12. Effect of operating frequency and phase angle on performance of Alpha Stirling cryocooler driven by a novel compact mechanism

    NASA Astrophysics Data System (ADS)

    Sant, K. D.; Bapat, S. L.

    2015-12-01

    Amongst the mechanical cryocoolers in use, Stirling cycle cryocoolers exhibit the desirable features such as high efficiency, low specific power consumption, small size and mass and large mean time before failure. Stirling cycle cryocooler of Alpha configuration exhibits better theoretical performance as compared to Gamma. However, the theory could not be put into practice due to unavailability of compatible drive mechanism for Alpha cryocooler providing large stroke to diameter ratio. The concept of novel compact drive mechanism can be made functional to operate miniature Alpha Stirling cryocoolers. It allows the use of multicylinder system while converting rotary motion to reciprocating. This permits the drive mechanism to be employed for driving different configurations of Stirling cryocooler simultaneously. This drive is capable of providing large stroke to diameter ratio compared to other drive mechanisms generally in use for the purpose. A stroke to diameter ratio of three is chosen in the present work and the drive dimensions are calculated for four piston-cylinder arrangements with 90° phase difference between adjacent arrangements providing two Alpha Stirling cryocoolers working simultaneously. It has to be noted that the coolers operate at half the frequency of the motor used. As the two coolers operate at phase difference of 180°, during compression stroke of one unit, the suction stroke occurs for the other unit. Due to power output of second unit, the combined peak torque requirement falls by 26.81% below the peak torque needed when one unit is operated separately. This allows for use of a comparatively lower torque motor. The practicability of the drive ensuring smooth operation of the system is decided based on comparison between torque availability from the motor and torque requirement of the complete unit. The second order method of cyclic (or thermodynamic) analysis provides a simple computational procedure useful for the design of Stirling cryocooler and is adopted for the present theoretical investigations. An appropriate choice of the equations to compute different losses, from available co-relations, is made in accordance with the conditions existing in the present system. The effects of operating frequency and phase angle between compressor and expander pistons are presented in this paper. The cryocooler performance enhances with increase in operating frequency. However, cryocooler operation at 24 Hz (motor operation at 48 Hz) is considered for theoretical performance prediction. The maximum net refrigeration effect as well as COP is available at phase angle of 81° However, it is essential to fix the phase angle at 90° for both the cryocoolers for the positive functioning of drive mechanism.

  13. Study of the human pelvis using CAT-scan: gender differences and anatomy of the ramus ossis ischii.

    PubMed

    van de Meent, Hendrik; Jansen, Harry; van der Linde, Harmen

    2008-12-01

    In a descriptive study we present the CAT-scan norm data of pelvic sizes in Caucasian men and women. The study was performed to investigate possible differences in pelvic sizes between men and women and the inter-individual range of pelvic sizes. The data may be useful as a guide in the development of orthoses and prostheses. Pelvis CAT-scans of 40 subjects, 20 males (23-66 years) and 20 females (20-72 years) were investigated. The research was approved by the regional ethics committee. The angle of the ramus ossis ischii (ROI) with the line of progression in the transverse plane (angle a) was 38.6 degrees (SD 3.4) in females and 31.8 degrees (SD 4.4) in males. This difference was statistically significant (Student's t-test (p < 0.0001). The ROI angle in the coronal plane (angle b) was negative or zero both in males and females. The horizontal distance between the medial border of the ROI and the lateral border of the femur (RF distance) was slightly smaller in females (95 mm) compared to males (107 mm), but this difference was not statistically significant. The distance between the midfemoral line and the anterior surface of the leg was also slightly smaller in females (89 mm) than in males (106 mm) but the difference was not statistically significant. We found a linear relation between the total AP soft tissue distance and the soft tissue circumference of the proximal leg at the level of the ROI. There are significant gender differences in pelvic size and shape. The medial plane of the ROI is not in a slight angle of inclination towards the midline but appears to be zero. The medial contour of the ROI in the AP direction is slightly curved.

  14. Spin-torque diode with tunable sensitivity and bandwidth by out-of-plane magnetic field

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

    Li, X.; Zheng, C.; Pong, Philip W. T.

    Spin-torque diodes based on nanosized magnetic tunnel junctions are novel microwave detectors with high sensitivity and wide frequency bandwidth. While previous reports mainly focus on improving the sensitivity, the approaches to extend the bandwidth are limited. This work experimentally demonstrates that through optimizing the orientation of the external magnetic field, wide bandwidth can be achieved while maintaining high sensitivity. The mechanism of the frequency- and sensitivity-tuning is investigated through analyzing the dependence of resonant frequency and DC voltage on the magnitude and the tilt angle of hard-plane magnetic field. The frequency dependence is qualitatively explicated by Kittel's ferromagnetic resonance model.more » The asymmetric resonant frequency at positive and negative magnetic field is verified by the numerical simulation considering the in-plane anisotropy. The DC voltage dependence is interpreted through evaluating the misalignment angle between the magnetization of the free layer and the reference layer. The tunability of the detector performance by the magnetic field angle is evaluated through characterizing the sensitivity and bandwidth under 3D magnetic field. The frequency bandwidth up to 9.8 GHz or maximum sensitivity up to 154 mV/mW (after impedance mismatch correction) can be achieved by tuning the angle of the applied magnetic field. The results show that the bandwidth and sensitivity can be controlled and adjusted through optimizing the orientation of the magnetic field for various applications and requirements.« less

  15. Changing Sagittal-Plane Landing Styles to Modulate Impact and Tibiofemoral Force Magnitude and Directions Relative to the Tibia

    PubMed Central

    Shimokochi, Yohei; Ambegaonkar, Jatin P.; Meyer, Eric G.

    2016-01-01

    Context: Ground reaction force (GRF) and tibiofemoral force magnitudes and directions have been shown to affect anterior cruciate ligament loading during landing. However, the kinematic and kinetic factors modifying these 2 forces during landing are unknown. Objective: To clarify the intersegmental kinematic and kinetic links underlying the alteration of the GRF and tibiofemoral force vectors secondary to changes in the sagittal-plane body position during single-legged landing. Design: Crossover study. Setting: Laboratory. Patients or Other Participants: Twenty recreationally active participants (age = 23.4 ± 3.6 years, height = 171.0 ± 9.4 cm, mass = 73.3 ± 12.7 kg). Intervention(s): Participants performed single-legged landings using 3 landing styles: self-selected landing (SSL), body leaning forward and landing on the toes (LFL), and body upright with flat-footed landing (URL). Three-dimensional kinetics and kinematics were recorded. Main Outcome Measure(s): Sagittal-plane tibial inclination and knee-flexion angles, GRF magnitude and inclination angles relative to the tibia, and proximal tibial forces at peak tibial axial forces. Results: The URL resulted in less time to peak tibial axial forces, smaller knee-flexion angles, and greater magnitude and a more anteriorly inclined GRF vector relative to the tibia than did the SSL. These changes led to the greatest peak tibial axial and anterior shear forces in the URL among the 3 landing styles. Conversely, the LFL resulted in longer time to peak tibial axial forces, greater knee-flexion angles, and reduced magnitude and a more posteriorly inclined GRF vector relative to the tibia than the SSL. These changes in LFL resulted in the lowest peak tibial axial and largest posterior shear forces among the 3 landing styles. Conclusions: Sagittal-plane intersegmental kinematic and kinetic links strongly affected the magnitude and direction of GRF and tibiofemoral forces during the impact phase of single-legged landing. Therefore, improving sagittal-plane landing mechanics is important in reducing harmful magnitudes and directions of impact forces on the anterior cruciate ligament. PMID:27723362

  16. 33 CFR 183.3 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... defined by a series of points of contact, with the boat structure, by straight lines at 45 degree angles... the line defined by a series of points of contact with the boat structure, by straight lines at 45 degree angles to the horizontal and contained in a vertical plane normal to the outside edge of the boat...

  17. 14 CFR 29.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 0° to 10°10° to 20° 20° to 110° 4030 5 A (rear white...

  18. 14 CFR 23.1391 - Minimum intensities in the horizontal plane of position lights.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (red and green) 0° to 10°10° to 20° 20° to 110° 4030 5 A (rear white) 110° to...

  19. 14 CFR 29.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 0° to 10°10° to 20° 20° to 110° 4030 5 A (rear white...

  20. 14 CFR 27.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 10° to 10°10° to 20° 20° to 110° 4030 5 A (rear white...

  1. 14 CFR 25.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 0° to 10°10° to 20° 20° to 110° 4030 5 A (rear white...

  2. 14 CFR 23.1391 - Minimum intensities in the horizontal plane of position lights.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (red and green) 0° to 10°10° to 20° 20° to 110° 4030 5 A (rear white) 110° to...

  3. 14 CFR 25.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 0° to 10° 10° to 20° 20° to 110° 40 30 5 A (rear white...

  4. 14 CFR 29.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 0° to 10°10° to 20° 20° to 110° 4030 5 A (rear white...

  5. 14 CFR 27.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 10° to 10°10° to 20° 20° to 110° 4030 5 A (rear white...

  6. 14 CFR 25.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 0° to 10°10° to 20° 20° to 110° 4030 5 A (rear white...

  7. 14 CFR 27.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 10° to 10°10° to 20° 20° to 110° 4030 5 A (rear white...

  8. 14 CFR 23.1391 - Minimum intensities in the horizontal plane of position lights.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (red and green) 0° to 10°10° to 20° 20° to 110° 4030 5 A (rear white) 110° to...

  9. 14 CFR 27.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 10° to 10°10° to 20° 20° to 110° 4030 5 A (rear white...

  10. 14 CFR 25.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 0° to 10° 10° to 20° 20° to 110° 40 30 5 A (rear white...

  11. 14 CFR 29.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 0° to 10°10° to 20° 20° to 110° 4030 5 A (rear white...

  12. 14 CFR 23.1391 - Minimum intensities in the horizontal plane of position lights.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (red and green) 0° to 10°10° to 20° 20° to 110° 4030 5 A (rear white) 110° to...

  13. Parametric study of beam refraction problems across laser anemometer windows

    NASA Technical Reports Server (NTRS)

    Owen, A. K.

    1986-01-01

    The experimenter is often required to view flows through a window with a different index of refraction than either the medium being observed or the medium that the laser anemometer is immersed in. The refraction that occurs at the window surfaces may lead to undesirable changes in probe volume position or beam crossing angle and can lead to partial or complete beam uncrossing. This report describes the results of a parametric study of this problem using a ray tracing technique to predict these changes. The windows studied were a flat plate and a simple cyclinder. For the flat-plate study: (1) surface thickness, (2) beam crossing angle, (3) bisecting line - surface normal angle, and (4) incoming beam plane surface orientation were varied. For the cylindrical window additional parameters were also varied: (1) probe volume immersion, (2) probe volume off-radial position, and (3) probe volume position out of the R-theta plane of the lens. A number of empirical correlations were deduced to aid the interested reader in determining the movement, uncrossing, and change in crossing angle for a particular situation.

  14. A parametric study of the beam refraction problems across laser anemometer windows

    NASA Technical Reports Server (NTRS)

    Owen, Albert K.

    1986-01-01

    The experimenter is often required to view flows through a window with a different index of refraction than either the medium being observed or the medium that the laser anemometer is immersed in. The refraction that occurs at the window surfaces may lead to undesirable changes in probe volume position or beam crossing angle and can lead to partial or complete beam uncrossing. This report describes the results of a parametric study of this problem using a ray tracing technique to predict these changes. The windows studied were a flat plate and a simple cylinder. For the flat-plate study: (1) surface thickness, (2) beam crossing angle, (3) bisecting line - surface normal angle, and (4) incoming beam plane surface orientation were varied. For the cylindrical window additional parameters were also varied: (1) probe volume immersion, (2) probe volume off-radial position, and (3) probe volume position out of the r-theta plane of the lens. A number of empirical correlations were deduced to aid the reader in determining the movement, uncrossing, and change in crossing angle for a particular situations.

  15. Jet-Boundary Corrections for Reflection-Plane Models in Rectangular Wind Tunnels

    DTIC Science & Technology

    1943-01-01

    clock- wiso) located at a distance d above the tunnel center line and at distances equal to VIand —vI from the reflection wall. Tho single trailing vortex...neglected. The angle-.xkmnge is usually small, les than %O. M & fw-refleciicur plane models in 7-by 10-foof cIosedrectangular wind fu-meIs 04

  16. 14 CFR 23.771 - Pilot compartment.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... the propellers so that no part of the pilot or the controls lies in the region between the plane of rotation of any inboard propeller and the surface generated by a line passing through the center of the propeller hub making an angle of 5 degrees forward or aft of the plane of rotation of the propeller. [Doc...

  17. 14 CFR 23.771 - Pilot compartment.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... the propellers so that no part of the pilot or the controls lies in the region between the plane of rotation of any inboard propeller and the surface generated by a line passing through the center of the propeller hub making an angle of 5 degrees forward or aft of the plane of rotation of the propeller. [Doc...

  18. 14 CFR 23.771 - Pilot compartment.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... the propellers so that no part of the pilot or the controls lies in the region between the plane of rotation of any inboard propeller and the surface generated by a line passing through the center of the propeller hub making an angle of 5 degrees forward or aft of the plane of rotation of the propeller. [Doc...

  19. Forelimb posture in dinosaurs and the evolution of the avian flapping flight-stroke.

    PubMed

    Nudds, Robert L; Dyke, Gareth J

    2009-04-01

    Ontogenetic and behavioral studies using birds currently do not document the early evolution of flight because birds (including juveniles) used in such studies employ forelimb oscillation frequencies over 10 Hz, forelimb stroke-angles in excess of 130 degrees , and possess uniquely avian flight musculatures. Living birds are an advanced morphological stage in the development of flapping flight. To gain insight into the early stages of flight evolution (i.e., prebird), in the absence of a living analogue, a new approach using Strouhal number was used. Strouhal number is a nondimensional number that describes the relationship between wing-stroke amplitude (A), wing-beat frequency (f), and flight speed (U). Calculations indicated that even moderate wing movements are enough to generate rudimentary thrust and that a propulsive flapping flight-stroke could have evolved via gradual incremental changes in wing movement and wing morphology. More fundamental to the origin of the avian flapping flight-stroke is the question of how a symmetrical forelimb posture-required for gliding and flapping flight-evolved from an alternating forelimb motion, evident in all extant bipeds when running except birds.

  20. Effect of Core Stability Training on Trunk Function, Standing Balance, and Mobility in Stroke Patients.

    PubMed

    Haruyama, Koshiro; Kawakami, Michiyuki; Otsuka, Tomoyoshi

    2017-03-01

    Trunk function is important for standing balance, mobility, and functional outcome after stroke, but few studies have evaluated the effects of exercises aimed at improving core stability in stroke patients. To investigate the effectiveness of core stability training on trunk function, standing balance, and mobility in stroke patients. An assessor-blinded, randomized controlled trial was undertaken in a stroke rehabilitation ward, with 32 participants randomly assigned to an experimental group or a control group (n = 16 each). The experimental group received 400 minutes of core stability training in place of conventional programs within total training time, while the control group received only conventional programs. Primary outcome measures were evaluated using the Trunk Impairment Scale (TIS), which reflects trunk function. Secondary outcome measures were evaluated by pelvic tilt active range of motion in the sagittal plane, the Balance Evaluation Systems Test-brief version (Brief-BESTest), Functional Reach test, Timed Up-and-Go test (TUG), and Functional Ambulation Categories (FAC). A general linear repeated-measures model was used to analyze the results. A treatment effect was found for the experimental group on the dynamic balance subscale and total score of the TIS ( P = .002 and P < .001, respectively), pelvic tilt active range of motion ( P < .001), Brief-BESTest ( P < .001), TUG ( P = .008), and FAC ( P = .022). Core stability training has beneficial effects on trunk function, standing balance, and mobility in stroke patients. Our findings might provide support for introducing core stability training in stroke rehabilitation.

  1. [A new method to orthodontically correct dental occlusal plane canting: wave-shaped arch].

    PubMed

    Zheng, X; Hu, X X; Ma, N; Chen, X H

    2017-02-18

    To introduce a technique of second order wave-shaped arch wire to orthodontically treat dental occlusal plane canting (DOPC) with left-right interactive anchorage, and to test its clinical efficacy. Among the permanent dentition malocclusion patients who showed no obvious facial asymmetry, we screened for patients who showed anterior occlusal plane canting (AOPC) after routine orthodontic examination, treatment planning, MBT fixed appliance installation and serial arch wires alignment. Each patient had been clinically appraised in frontal view by 2 orthodontists and the patient him/herself; if all 3 agreed that the AOPC was obvious, the patient was included. By this means, we included 37 patients, including 10 males and 27 females; the average age was (21.9±5.2) years. To correct AOPC, opposite direction equal curvature second order rocking-chair curve was bent on each side of 0.46 mm×0.56 mm stainless steel edgewise wire. With reference to normal occlusal plane, a curve toward the occlusal surface was made to extrude under-erupted teeth on one side while a curve toward the gingiva was made to intrude over-erupted teeth on the other side, so that the arch wire was made into a wave shape in vertical dimension. Before and after application of wave-shaped arch wire, frontal facial photographs were taken when the patient's mouth was open slightly with lips retracted to show anterior occlusal plane (AOP) clearly. An AOP was constructed by connecting the center of the slot in the medial edge of canine bracket on each side in the photograph. The angles between the bipupillary plane(BPP) and the constructed AOP were measured in ImageJ1-48v software and the angle differences before and after treatment were compared with paired Wilcoxon test in SPSS 10.0 software. The wave-shaped arch could correct AOPC effectively in 3 to 10 months time with an average of 5.5±1.7 months; the angles between AOP and BBP before treatment ranged from 2.90° to 6.12° with a median of 4.01°; after treatment the angles were from -0.17° to 2.57° with a median of 1.87°, the decrease of the angles between AOP and BBP after treatment ranged from 1.08° to 4.15° with a median of 2.21°. Paired Wilcoxon test P was 0.000. The wave-shaped arch can be used independently or in combination with other treatment methods, which can take advantage of left and right interactive anchorage to correct AOPC effectively, so it has certain application value in clinical practice.

  2. The effects of prosthetic foot stiffness on transtibial amputee walking mechanics and balance control during turning.

    PubMed

    Shell, Courtney E; Segal, Ava D; Klute, Glenn K; Neptune, Richard R

    2017-11-01

    Little evidence exists regarding how prosthesis design characteristics affect performance in tasks that challenge mediolateral balance such as turning. This study assesses the influence of prosthetic foot stiffness on amputee walking mechanics and balance control during a continuous turning task. Three-dimensional kinematic and kinetic data were collected from eight unilateral transtibial amputees as they walked overground at self-selected speed clockwise and counterclockwise around a 1-meter circle and along a straight line. Subjects performed the walking tasks wearing three different ankle-foot prostheses that spanned a range of sagittal- and coronal-plane stiffness levels. A decrease in stiffness increased residual ankle dorsiflexion (10-13°), caused smaller adaptations (<5°) in proximal joint angles, decreased residual and increased intact limb body support, increased residual limb propulsion and increased intact limb braking for all tasks. While changes in sagittal-plane joint work due to decreased stiffness were generally consistent across tasks, effects on coronal-plane hip work were task-dependent. When the residual limb was on the inside of the turn and during straight-line walking, coronal-plane hip work increased and coronal-plane peak-to-peak range of whole-body angular momentum decreased with decreased stiffness. Changes in sagittal-plane kinematics and kinetics were similar to those previously observed in straight-line walking. Mediolateral balance improved with decreased stiffness, but adaptations in coronal-plane angles, work and ground reaction force impulses were less systematic than those in sagittal-plane measures. Effects of stiffness varied with the residual limb inside versus outside the turn, which suggests that actively adjusting stiffness to turn direction may be beneficial. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. A DSP-based readout and online processing system for a new focal-plane polarimeter at AGOR

    NASA Astrophysics Data System (ADS)

    Hagemann, M.; Bassini, R.; van den Berg, A. M.; Ellinghaus, F.; Frekers, D.; Hannen, V. M.; Häupke, T.; Heyse, J.; Jacobs, E.; Kirsch, M.; Krüsemann, B.; Rakers, S.; Sohlbach, H.; Wörtche, H. J.

    1999-11-01

    A Focal-Plane Polarimeter (FPP) for the large acceptance Big-Bite Spectrometer (BBS) at AGOR using a novel readout architecture has been commissioned at the KVI Groningen. The instrument is optimized for medium-energy polarized proton scattering near or at 0°. For the handling of the high counting rates at extreme forward angles and for the suppression of small-angle scattering in the graphite analyzer, a high-performance data processing DSP system connecting to the LeCroy FERA and PCOS ECL bus architecture has been made operational and tested successfully. Details of the system and the functions of the various electronic components are described.

  4. Synchrotron-based EUV lithography illuminator simulator

    DOEpatents

    Naulleau, Patrick P.

    2004-07-27

    A lithographic illuminator to illuminate a reticle to be imaged with a range of angles is provided. The illumination can be employed to generate a pattern in the pupil of the imaging system, where spatial coordinates in the pupil plane correspond to illumination angles in the reticle plane. In particular, a coherent synchrotron beamline is used along with a potentially decoherentizing holographic optical element (HOE), as an experimental EUV illuminator simulation station. The pupil fill is completely defined by a single HOE, thus the system can be easily modified to model a variety of illuminator fill patterns. The HOE can be designed to generate any desired angular spectrum and such a device can serve as the basis for an illuminator simulator.

  5. Optimal plane change during constant altitude hypersonic flight

    NASA Technical Reports Server (NTRS)

    Mease, K. D.; Vinh, N. X.; Kuo, S. H.

    1988-01-01

    Future spacecraft operating in the vicinity of the earth may have resort to the atmosphere as an aid in effecting orbital change. While a previous treatment of this technique chose constant altitude, speed, and angle-of-attack values in order to maximize the plane change for a fixed amount of propellant consumption during hypersonic flight, the former two parameters are presently released from the constraint of constancy. The general characteristics of the optimal controls are described on the basis of the domain of maneuverability, and numerical solutions are obtained for several specific cases. Under the condition of constant-altitude flight, it is generally not optimal to fly at constant angle-of-attack.

  6. Observed changes in radiographic measurements of the first ray after frontal plane rotation of the first metatarsal in a cadaveric foot model.

    PubMed

    Dayton, Paul; Feilmeier, Mindi; Hirschi, Jordan; Kauwe, Merrell; Kauwe, John S K

    2014-01-01

    We observed the changes in the angular measurements commonly used in the evaluation of the first metatarsal and first metatarsophalangeal joint in cadaveric specimens before and after frontal plane rotation of the first metatarsal. Measurements of the first and second intermetatarsal angle (IMA), hallux abductus angle, proximal articular set angle, and tibial sesamoid position (TSP) were taken after varying degrees of varus and valgus rotation of the first metatarsal. Standard dorsoplantar radiographs were taken at 0°, 10°, 20°, and 30° of valgus rotation of the first metatarsal and repeated at 10°, 20°, and 30° varus rotation of the first metatarsal. The data were analyzed using a mixed linear model to compare the change in each angle measurement over the range of valgus and varus rotation. The change in the TSP was significant in both valgus and varus rotations (p = .0004 and p = .028, respectively), an increase in valgus rotation causing an increase in the TSP and an increase in varus rotation causing a decrease in TSP. The change in the IMA was significant compared with valgus rotation (p = .028), showing that as the valgus rotation increased, the IMA also increased. However, compared with the varus rotation, the correlation was not significant (p = .18). The proximal articular set angle and hallux abductus angle measurements, compared with metatarsal rotation, showed positive trends but were not statistically significant. From our results and a review of the published data, we have hypothesized that frontal plane rotation of the first metatarsal is an integral component of hallux abducto valgus pathologic features, specifically in relation to the TSP and IMA. Copyright © 2014 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  7. Relationships Between Age at Menarche, Walking Gait Base of Support, and Stance Phase Frontal Plane Knee Biomechanics in Adolescent Girls.

    PubMed

    Froehle, Andrew W; Grannis, Kimberly A; Sherwood, Richard J; Duren, Dana L

    2017-05-01

    Age at menarche impacts patterns of pubertal growth and skeletal development. These effects may carry over into variation in biomechanical profiles involved in sports-related traumatic and overuse knee injuries. The present study investigated whether age at menarche is a potential indicator of knee injury risk through its influence on knee biomechanics during normal walking. To test the hypothesis that earlier menarche is related to postpubertal biomechanical risk factors for knee injuries, including a wider, more immature gait base of support, and greater valgus knee angles and moments. Cross-sectional observational study. University research facility. Healthy, postmenarcheal, adolescent girls. Age at menarche was obtained by recall questionnaire. Pubertal growth and anthropometric data were collected by using standard methods. Biomechanical data were taken from tests of walking gait at self-selected speed. Reflective marker position data were collected with a 3-dimensional quantitative motion analysis system, and 3 force plates recorded kinetic data. Age at menarche; growth and anthropometric measurements; base of support; static knee frontal plane angle; and dynamic knee frontal plane angles and moments during stance. Earlier menarche was correlated significantly with abbreviated pubertal growth and postpubertal retention of immature traits, including a wider base of support. Earlier menarche and wider base of support were both correlated with more valgus static knee angles, more valgus knee abduction angles and moments at foot-strike, and a more valgus peak knee abduction angle during stance. Peak knee abduction moment during stance was not correlated with age at menarche or base of support. Earlier menarche and its effects on growth are associated with retention of a relatively immature gait base of support and a tendency for static and dynamic valgus knee alignment. This biomechanical profile may put girls with earlier menarche at greater risk for sports-related knee injuries. Not applicable. Copyright © 2017 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  8. Transverse-plane pelvic asymmetry in patients with cerebral palsy and scoliosis.

    PubMed

    Ko, Phebe S; Jameson, Paul G; Chang, Tai-Li; Sponseller, Paul D

    2011-01-01

    Pelvic obliquity and loss of sitting balance develop from progressive scoliosis in cerebral palsy (CP) and are indications for surgery. Our goal was to quantify pelvic asymmetry to help understand skeletal deformity in CP and its surgical correction. We assessed pelvic angles and transverse plane symmetry in 27 consecutive patients with scoliosis and severe CP who had undergone computed tomography for spinal surgery (subjects). The program used allowed measurement of angles in the true transverse plane, compensating for any obliquity present. Measurements included angles of the upper and lower ilium with respect to the sacrum, acetabular anteversion, and sacroiliac joint angles. We compared subject measurements with those of 20 age-matched controls and used Student t test to determine whether subjects had greater asymmetry and if the asymmetry direction was correlated with the adducted hip and/or the scoliosis in subjects with windswept hips. Subjects had significantly more iliac angle asymmetry (P=0.01) and asymmetry of at least 10 degrees in these categories: upper ilium, 15 (mean difference, 18); above sciatic notch, 14 (mean difference, 17); just below sciatic notch, 15 (mean difference, 19); sacroiliac joint, 5; and acetabular anteversion, 6. No control had asymmetry greater than 10 degrees. Comparing subjects with and without windswept hips, the former had more asymmetrical upper iliac angles. In 16 subjects with windswept hips, the scoliosis curve convexity was ipsilateral to the more internally rotated ilium. In 4 of the 5 subjects with severely windswept hips, the side of the adducted hip had more inward iliac rotation than did the contralateral (abducted) hip. Transverse pelvic asymmetry, a little-recognized deformity in patients with severe CP, is most pronounced above the acetabulum and is more common in patients with windswept hips. Spine surgeons should be aware of such asymmetry because it may make iliac fixation challenging and account for some persistent postoperative deformity. Case-control study, Level III.

  9. Relationships between age at menarche, walking gait base of support, and stance phase frontal plane knee biomechanics in adolescent females

    PubMed Central

    Grannis, Kimberly A.; Sherwood, Richard J.; Duren, Dana L

    2016-01-01

    Background Age at menarche impacts patterns of pubertal growth and skeletal development. These effects may carry over into variation in biomechanical profiles involved in sports-related traumatic and overuse knee injuries. The present study investigated whether age at menarche is a potential indicator of knee injury risk through its influence on knee biomechanics during normal walking. Objective To test the hypothesis that earlier menarche is related to post-pubertal biomechanical risk factors for knee injuries, including a wider, more immature gait base of support, and greater valgus knee angles and moments. Design Cross-sectional observational study. Setting University research facility. Participants Healthy, post-menarcheal, adolescent females. Methods Age at menarche was obtained by recall questionnaire. Pubertal growth and anthropometric data were collected using standard methods. Biomechanical data were taken from tests of walking gait at self-selected speed. Reflective marker position data were collected using a three-dimensional quantitative motion analysis system, and three force plates recorded kinetic data. Main Outcome Measures Age at menarche; growth and anthropometric measurements; base of support; static knee frontal plane angle; dynamic knee frontal plane angles and moments during stance. Results Earlier menarche was significantly correlated with abbreviated pubertal growth and post-pubertal retention of immature traits, including a wider base of support. Earlier menarche and wider base of support were both correlated with more valgus static knee angles, more valgus knee abduction angles and moments at foot-strike, and a more valgus peak knee abduction angle during stance. Peak knee abduction moment during stance was not correlated with age at menarche or base of support. Conclusions Earlier menarche and its effects on growth are associated with retention of a relatively immature gait base of support and a tendency for static and dynamic valgus knee alignment. This biomechanical profile may put girls with earlier menarche at higher risk for sports-related knee injuries. PMID:27485675

  10. Gait switches in deep-diving beaked whales: biomechanical strategies for long-duration dives.

    PubMed

    Martín López, Lucía Martina; Miller, Patrick J O; Aguilar de Soto, Natacha; Johnson, Mark

    2015-05-01

    Diving animals modulate their swimming gaits to promote locomotor efficiency and so enable longer, more productive dives. Beaked whales perform extremely long and deep foraging dives that probably exceed aerobic capacities for some species. Here, we use biomechanical data from suction-cup tags attached to three species of beaked whales (Mesoplodon densirostris, N=10; Ziphius cavirostris, N=9; and Hyperoodon ampullatus, N=2) to characterize their swimming gaits. In addition to continuous stroking and stroke-and-glide gaits described for other diving mammals, all whales produced occasional fluke-strokes with distinctly larger dorso-ventral acceleration, which we termed 'type-B' strokes. These high-power strokes occurred almost exclusively during deep dive ascents as part of a novel mixed gait. To quantify body rotations and specific acceleration generated during strokes we adapted a kinematic method combining data from two sensors in the tag. Body rotations estimated with high-rate magnetometer data were subtracted from accelerometer data to estimate the resulting surge and heave accelerations. Using this method, we show that stroke duration, rotation angle and acceleration were bi-modal for these species, with B-strokes having 76% of the duration, 52% larger body rotation and four times more surge than normal strokes. The additional acceleration of B-strokes did not lead to faster ascents, but rather enabled brief glides, which may improve the overall efficiency of this gait. Their occurrence towards the end of long dives leads us to propose that B-strokes may recruit fast-twitch fibres that comprise ∼80% of swimming muscles in Blainville's beaked whales, thus prolonging foraging time at depth. © 2015. Published by The Company of Biologists Ltd.

  11. Multiple embryos, multiple nepionts and multiple equatorial layers in Cycloclypeus carpenteri.

    NASA Astrophysics Data System (ADS)

    Briguglio, Antonino; Kinoshita, Shunichi; Wolfgring, Erik; Hohenegger, Johann

    2016-04-01

    In this study, 17 specimens of Cycloclypeus carpenteri have been analyzed by means of microCT scanning. We used CT scanning technique as it enables the visualization and the quantifications of internal structures of hollow specimens without their destruction. It has been observed that many specimens possessing the natural morphology of this taxon, actually contain multiple embryos (up to 16 in one single specimen) and, in some few cases, multiple nepionts each with its own heterosteginid chambers (up to three separated nepionts). The diameter of each proloculus has been measured, and as a result, they are very variable even within the same specimen, therefore questioning the long known theory that schizonts have smaller proloculi than gamonts and also questioning the fact that proloculi in the same species should all have comparable size. Furthermore, we have observed the presence of additional equatorial planes on several specimens. Such additional planes are always connected to what seems to be the main equatorial plane. Such connections are T-shaped and are located at the junction between two equatorial layers; these junctions are made by a chamberlet, which possesses an unusually higher number of apertures. The connections between equatorial planes are always perfectly synchronized with the relative growth step and the same chamber can be therefore followed along the multiple equatorial planes. Apparently there is a perfect geometric relationship between the creation of additional equatorial planes and the position of the nepionts. Whenever the nepionts are positioned on different planes, additional planes are created and the angle of the nepionts is related to the banding angle of the equatorial planes. The presence of additional planes do not hamper the life of the cell, on the contrary, it seems that the cell is still able to build nicely shaped chamberlets and, after volumetric calculations, it seems all specimens managed to keep their logistic growth function.

  12. Determination of 3D optic axis orientation in cartilage by polarization-sensitive optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Ugryumova, Nadya; Bonesi, Marco; Matcher, Stephen J.

    2008-02-01

    Polarization-sensitive optical coherence tomography has been used to solve fast-axis fibre orientation in three dimension space. Previously we have demonstrated that the apparent variations in polar angle orientation of collagen fibers along sagittal ridge of equine third metacarpophalangeal joint exist. A quantitative method based on multiple angles of illumination has been proposed to determine the polar angle of the collagen fibers. This method however ignored the full 3D structure by assuming that the collagen fibers long-axis lay within the plane of incidence. A new quantitative method based on the theory of light propagation in uniaxial materials is described which avoids this assumption. To test this method we have performed control experiments on a sample of equine tendon (this tissue has well defined c-axis lying along the long-axis of the tendon). Several samples of tendon were cut to achieve a planar surface inclined at -20° to the long axis. Additional 30° rotation provided non-zero azimuthal angle. The surface was then imaged using incident beam angles -40°, -20°, 0, +20°, +40° in two orthogonal planes. Values for both the polar and azimuthal angles were then derived using a numerical optimisation procedure. Results agreed qualitatively with the nominal values but suggested that the accuracy was limited by our method of determining the apparent birefringence.

  13. Determination of 3D optic axis orientation in cartilage by polarization-sensitive optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Ugryumova, Nadya; Matcher, Stephen J.

    2007-02-01

    Polarization-sensitive optical coherence tomography has been used to solve fast-axis fibre orientation in three dimension space. Previously we have demonstrated that the apparent variations in polar angle orientation of collagen fibers along sagittal ridge of equine third metacarpophalangeal joint exist. A quantitative method based on multiple angles of illumination has been proposed to determine the polar angle of the collagen fibers. This method however ignored the full 3-D structure by assuming that the collagen fibers long-axis lay within the plane of incidence. A new quantitative method based on the theory of light propagation in uniaxial materials is described which avoids this assumption. To test this method we have performed control experiments on a sample of equine tendon (this tissue has well defined c-axis lying along the long-axis of the tendon). Several samples of tendon were cut to achieve a planar surface inclined at -20° to the long axis. Additional 30° rotation provided non-zero azimuthal angle. The surface was then imaged using incident beam angles -40°, -20°, 0, +20°, +40° in two orthogonal planes. Values for both the polar and azimuthal angles were then derived using a numerical optimisation procedure. Results agreed qualitatively with the nominal values but suggested that the accuracy was limited by our method of determining the apparent birefringence.

  14. Effects of a lower limb functional exercise programme aimed at minimising knee valgus angle on running kinematics in youth athletes.

    PubMed

    Sheerin, Kelly R; Hume, Patria A; Whatman, Chris

    2012-11-01

    To investigate the effectiveness of 8-weeks of lower limb functional exercises on frontal plane hip and knee angles during running in youth athletes. Pre- and post-intervention quantitative experimental. Nineteen athletes (11 male, 8 female, 11.54 ± 1.34 years) from a long-term athletic development programme had 3-dimensional running gait measured pre and post an 8-week exercise intervention. Youth athletes randomised to control (upper limb strengthening exercises) or experimental (lower limb functional exercises aimed at minimising knee valgus angle) interventions completed the exercises during the first 10 min of training, three mornings a week. Pre- and post-parallel groups' analysis provided estimates of intervention effects for control and experimental groups. Differences in pre- to post-intervention changes in mean frontal plane angles between control and experimental groups were trivial for the left hip (0.1°) and right knee (-0.3°). There was a small beneficial decrease in right hip joint angle (0.4°) but a very large (ES = 0.77, CI 0.1-3.7) detrimental increase in left knee valgus angle (1.9°) between groups. The 8-week lower limb functional exercises had little beneficial effects on lower limb hip and knee mechanics in youth athletes aged 9-14 years. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. LIMITED HIP AND KNEE FLEXION DURING LANDING IS ASSOCIATED WITH INCREASED FRONTAL PLANE KNEE MOTION AND MOMENTS

    PubMed Central

    Pollard, Christine D.; Sigward, Susan M.; Powers, Christopher M.

    2009-01-01

    Background It has been proposed that female athletes who limit knee and hip flexion during athletic tasks rely more on the passive restraints in the frontal plane to deceleration their body center of mass. This biomechanical pattern is thought to increase the risk for anterior cruciate ligament injury. To date, the relationship between sagittal plane kinematics and frontal plane knee motion and moments has not been explored. Methods Subjects consisted of fifty-eight female club soccer players (age range: 11 to 20 years) with no history of knee injury. Kinematics, ground reaction forces, and surface electromyography were collected while each subject performed a drop landing task. Subjects were divided into two groups based on combined sagittal plane knee and hip flexion angles during the deceleration phase of landing (high flexion and low flexion). Findings Subjects in the low flexion group demonstrated increased knee valgus angles (P = 0.02, effect size 0.27), increased knee adductor moments (P = 0.03, effect size 0.24), decreased energy absorption at the knee and hip (P = 0.02, effect size 0.25; and P< 0.001, effect size 0.59), and increased vastus lateralis EMG when compared to subjects in the high flexion group (P = 0.005, effect size 0.35). Interpretation Female athletes with limited sagittal plane motion during landing exhibit a biomechanical profile that may put these individuals at greater risk for anterior cruciate ligament injury. PMID:19913961

  16. Relationship between hip and core strength and frontal plane alignment during a single leg squat.

    PubMed

    Stickler, Laurie; Finley, Margaret; Gulgin, Heather

    2015-02-01

    The purpose of this study was to examine the relationship between frontal plane kinematics of the single leg squat and strength of the trunk and hip in females. Forty healthy females participated in this study. An isometric "make" test using a dynamometer was used to assess peak force normalized to body weight for hip abduction, hip extension, hip external rotation, and a sidelying plank test. Two-dimensional software was used to analyze the frontal plane projection angle (FPPA) and pelvic angle during a single leg squat to 60°. All 4 strength factors were significantly correlated with the FPPA, ranging from r = 0.396 to r = 0.466. During multiple regression analysis, hip abduction strength was the greatest predictor of the variation in FPPA at r(2) = 0.22, p = 0.002. Thus, hip abduction strength accounted for 22% of the variation in the FPPA during the single leg squat. The only strength factor demonstrating a significant correlation with the pelvic angle was hip extension strength (r = 0.550, p < 0.001). Clinicians should consider the role of the hip abductors, hip external rotators, hip extensors and core musculature on the impact on the FPPA during a single squat, with focus on the hip abductors. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. The 20 April 2013 Lushan, Sichuan, mainshock, and its aftershock sequence: tectonic implications

    NASA Astrophysics Data System (ADS)

    Lei, Jianshe; Zhang, Guangwei; Xie, Furen

    2014-02-01

    Using the double-difference relocation algorithm, we relocated the 20 April 2013 Lushan, Sichuan, earthquake ( M S 7.0), and its 4,567 aftershocks recorded during the period between 20 April and May 3, 2013. Our results showed that most aftershocks are relocated between 10 and 20 km depths, but some large aftershocks were relocated around 30 km depth and small events extended upward near the surface. Vertical cross sections illustrate a shovel-shaped fault plane with a variable dip angle from the southwest to northeast along the fault. Furthermore, the dip angle of the fault plane is smaller around the mainshock than that in the surrounding areas along the fault. These results suggest that it may be easy to generate the strong earthquake in the place having a small dip angle of the fault, which is somewhat similar to the genesis of the 2008 Wenchuan earthquake. The Lushan mainshock is underlain by the seismically anomalous layers with low-VP, low-VS, and high-Poisson's ratio anomalies, possibly suggesting that the fluid-filled fractured rock matrices might significantly reduce the effective normal stress on the fault plane to bring the brittle failure. The seismic gap between Lushan and Wenchuan aftershocks is suspected to be vulnerable to future seismic risks at greater depths, if any.

  18. Effect of Seat Tube Angle and Exercise Intensity on Muscle Activity Patterns in Cyclists

    PubMed Central

    DUGGAN, WILL; DONNE, BERNARD; FLEMING, NEIL

    2017-01-01

    Previous studies have reported improved efficiency at steeper seat tube angle (STA) during ergometer cycling; however, neuromuscular mechanisms have yet to be fully determined. The current study investigated effects of STA on lower limb EMG activity at varying exercise intensities. Cyclists (n=11) were tested at 2 workloads; 160W and an individualised workload (IWL) equivalent to lactate threshold (TLac) minus 10%δ (derived from maximal incremental data), using 3 STA (70, 75 and 80°). Electromyographic data from Vastus Medialis (VM), Rectus Femoris (RF), Vastus Lateralis (VL) and Biceps Femoris (BF) were assessed. The timing and magnitude of activation were quantified and analysed using a two-way ANOVA. STA had significant (P < 0.05) effects on timing of onset and offset of VM, timing of offset of VL, and angle at peak for RF, all occurring later at 80 vs. 70° STA at IWL. In RF, increased activity occurred during the first 108° of the crank cycle at 80 vs. 70° at IWL (P < 0.01). As most of the power in the pedal stroke is generated during the mid-section of the down-stroke, movement of the activation range of knee extensors into the predominantly power phase of the pedal stroke would potentially account for increased efficiency and decreased cardio-respiratory costs. Greater activity of bi-articular RF, in the first 108º of the crank cycle at IWL (80 vs. 70º) may more closely resemble the pelvic stabilising activity of RF in running biomechanics; and potentially explain the more effective transition from cycling to running reported in triathletes using steeper STA. PMID:29399245

  19. An anisotropic lens for transitioning plane waves between media of different permittivities

    NASA Astrophysics Data System (ADS)

    Stone, Alexander P.; Baum, Carl E.

    1988-11-01

    A particularly simple geometry is considered in which an inhomogeneous and anisotropic lens is specified for the transition of plane waves between media of different permittivities. The permittivities of the regions outside of the lens can be constant, but the permittivity of the lens region depends on position. Results are presented for a plane wave in the second medium propagating normally to the assumed plane boundary of that medium. The results for the case of normal incidence are then generalized to the case of nonnormal incidence. The conditions of transit time conservation and impedance matching are related to the Brewster angle.

  20. Determination of Focal Mechanisms of Non-Volcanic Tremors Based on S-Wave Polarization Data Corrected for the Effects of Anisotropy

    NASA Astrophysics Data System (ADS)

    Imanishi, K.; Uchide, T.; Takeda, N.

    2014-12-01

    We propose a method to determine focal mechanisms of non-volcanic tremors (NVTs) based on S-wave polarization angles. The successful retrieval of polarization angles in low S/N tremor signals owes much to the observation that NVTs propagate slowly and therefore they do not change their location immediately. This feature of NVTs enables us to use a longer window to compute a polarization angle (e.g., one minute or longer), resulting in a stack of particle motions. Following Zhang and Schwartz (1994), we first correct for the splitting effect to recover the source polarization angle (anisotropy-corrected angle). This is a key step, because shear-wave splitting distorts the particle motion excited by a seismic source. We then determine the best double-couple solution using anisotropy-corrected angles of multiple stations. The present method was applied to a tremor sequence at Kii Peninsula, southwest Japan, which occurred at the beginning of April 2013. A standard splitting and polarization analysis were subject to a one-minute-long moving window to determine the splitting parameters as well as anisotropy-corrected angles. A grid search approach was performed at each hour to determine the best double-couple solution satisfying one-hour average polarization angles. Most solutions show NW-dipping low-angle planes consistent with the plate boundary or SE-dipping high-angle planes. Because of 180 degrees ambiguity in polarization angles, the present method alone cannot distinguish compressional quadrant from dilatational one. Together with the observation of very low-frequency earthquakes near the present study area (Ito et al., 2007), it is reasonable to consider that they represent shear slip on low-angle thrust faults. It is also noted that some of solutions contain strike-slip component. Acknowledgements: Seismograph stations used in this study include permanent stations operated by NIED (Hi-net), JMA, Earthquake Research Institute, together with Geological Survey of Japan, AIST. This work was supported by JSPS KAKENHI Grant Number 24540463.

  1. Aerodynamic Measurements of a Variable-Speed Power-Turbine Blade Section in a Transonic Turbine Cascade at Low Inlet Turbulence

    NASA Technical Reports Server (NTRS)

    Flegel-McVetta, Ashlie B.; Giel, Paul W.; Welch, Gerard E.

    2013-01-01

    Aerodynamic measurements obtained in a transonic linear cascade were used to assess the impact of large incidence angle and Reynolds number variations on the 3-D flow field and midspan loss and turning of a 2-D section of a variable-speed power-turbine (VSPT) rotor blade. Steady-state data were obtained for ten incidence angles ranging from +15.8 deg to -51.0 deg. At each angle, data were acquired at five flow conditions with the exit Reynolds number (based on axial chord) varying over an order-of-magnitude from 2.12×10(exp 5) to 2.12×10(exp 6). Data were obtained at the design exit Mach number of 0.72 and at a reduced exit Mach number of 0.35 as required to achieve the lowest Reynolds number. Midspan total-pressure and exit flow angle data were acquired using a five-hole pitch/yaw probe surveyed on a plane located 7.0 percent axial chord downstream of the blade trailing edge plane. The survey spanned three blade passages. Additionally, three-dimensional half-span flow fields were examined with additional probe survey data acquired at 26 span locations for two key incidence angles of +5.8 deg and -36.7 deg. Survey data near the endwall were acquired with a three-hole boundary-layer probe. The data were integrated to determine average exit total-pressure and flow angle as functions of incidence and flow conditions. The data set also includes blade static pressures measured on four spanwise planes and endwall static pressures. Tests were conducted in the NASA Glenn Transonic Turbine Blade Cascade Facility. The measurements reflect strong secondary flows associated with the high aerodynamic loading levels at large positive incidence angles and an increase in loss levels with decreasing Reynolds number. The secondary flows decrease with negative incidence as the blade becomes unloaded. Transitional flow is admitted in this low inlet turbulence dataset, making it a challenging CFD test case. The dataset will be used to advance understanding of the aerodynamic challenges associated with maintaining efficient power turbine operation over a wide shaft-speed range. deg

  2. Muscular Proprioception Contributes to the Control of Interceptive Actions

    ERIC Educational Resources Information Center

    Bastin, Julien; Calvin, Sarah; Montagne, Gilles

    2006-01-01

    The authors proposed a model of the control of interceptive action over a ground plane (Chardenon, Montagne, Laurent, & Bootsma, 2004). This model is based on the cancellation of the rate of change of the angle between the current position of the target and the direction of displacement (i.e., the bearing angle). While several sources of visual…

  3. Computer Modelling of Cyclic Deformation of High-Temperature Materials

    DTIC Science & Technology

    1993-06-14

    possible plying the kink pair separation by the kink height a. to extract the thermodynamic parameters which This latter procedure is not accurate for...angle a(a) (a is the radius of the circle of intersection between particle and slip plane) by F = Vb2 sin a(a) where each breaking angle (a) relates to an

  4. Elementary properties of triangle in normed spaces

    NASA Astrophysics Data System (ADS)

    Triana, Deri; Yunus, Mahmud

    2018-03-01

    Based on concepts of trigonometric on plane, In this paper we generalized those concept in normed spaces. About the orthogonality concept between two vectors already well known, we are interested to develop elementary properties of triangle, especially the properties of its angle. We propose a non-linear (Wilson) functional to define an angle and explore its properties.

  5. Structure of collagen-glycosaminoglycan matrix and the influence to its integrity and stability.

    PubMed

    Bi, Yuying; Patra, Prabir; Faezipour, Miad

    2014-01-01

    Glycosaminoglycan (GAG) is a chain-like disaccharide that is linked to polypeptide core to connect two collagen fibrils/fibers and provide the intermolecular force in Collagen-GAG matrix (C-G matrix). Thus, the distribution of GAG in C-G matrix contributes to the integrity and mechanical properties of the matrix and related tissue. This paper analyzes the transverse isotropic distribution of GAG in C-G matrix. The angle of GAGs related to collagen fibrils is used as parameters to qualify the GAGs isotropic characteristic in both 3D and 2D rendering. Statistical results included that over one third of GAGs were perpendicular directed to collagen fibril with symmetrical distribution for both 3D matrix and 2D plane cross through collagen fibrils. The three factors tested in this paper: collagen radius, collagen distribution, and GAGs density, were not statistically significant for the strength of Collagen-GAG matrix in 3D rendering. However in 2D rendering, a significant factor found was the radius of collagen in matrix for the GAGs directed to orthogonal plane of Collagen-GAG matrix. Between two cross-section selected from Collagen-GAG matrix model, the plane cross through collagen fibrils was symmetrically distributed but the total percentage of perpendicular directed GAG was deducted by decreasing collagen radius. There were some symmetry features of GAGs angle distribution in selected 2D plane that passed through space between collagen fibrils, but most models showed multiple peaks in GAGs angle distribution. With less GAGs directed to perpendicular of collagen fibril, strength in collagen cross-section weakened. Collagen distribution was also a factor that influences GAGs angle distribution in 2D rendering. True hexagonal collagen packaging is reported in this paper to have less strength at collagen cross-section compared to quasi-hexagonal collagen arrangement. In this work focus is on GAGs matrix within the collagen and its relevance to anisotropy.

  6. Practice of Meteorological Services in Turpan Solar Eco-City in China (Invited)

    NASA Astrophysics Data System (ADS)

    Shen, Y.; Chang, R.; He, X.; Jiang, Y.; Zhao, D.; Ma, J.

    2013-12-01

    Turpan Solar Eco-City is located in Gobi in Northwest China, which is one of the National New Energy Demonstration Urban. The city was planed and designed from October of 2008 and constructed from May of 2010, and the first phase of the project has been completed by October of 2013. Energy supply in Turpan Solar Eco-City is mainly from PV power, which is installed in all of the roof and the total capacity is 13.4MW. During the planning and designing of the city, and the running of the smart grid, meteorological services have played an important role. 1) Solar Energy Resource Assessment during Planning Phase. According to the observed data from meteorological stations in recent 30 years, solar energy resource was assessed and available PV power generation capacity was calculated. The results showed that PV power generation capacity is 1.3 times the power consumption, that is, solar energy resource in Turpan is rich. 2) Key Meteorological Parameters Determination for Architectural Design. A professional solar energy resource station was constructed and the observational items included Global Horizontal Irradiance, Inclined Total Solar Irradiance at 30 degree, Inclined Total Solar Irradiance at local latitude, and so on. According these measured data, the optical inclined angle for PV array was determined, that is, 30 degree. The results indicated that the annual irradiation on inclined plane with optimal angle is 1.4% higher than the inclined surface with latitude angle, and 23.16% higher than the horizontal plane. The diffuse ratio and annual variation of the solar elevation angle are two major factors that influence the irradiation on inclined plane. 3) Solar Energy Resource Forecast for Smart Grid. Weather Research Forecast (WRF) model was used to forecast the hourly solar radiation of future 72 hours and the measured irradiance data was used to forecast the minutely solar radiation of future 4 hours. The forecast results were submitted to smart grid and used to regulate the local grid and the city gird.

  7. 49 CFR 571.218 - Standard No. 218; Motorcycle helmets.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... provide peripheral vision clearance of at least 105° to each side of the mid-sagittal plane, when the... basic plane that are within the angles of peripheral vision (see Figure 3). S5.5 Projections. A helmet... including 70 percent for a minimum of 4 hours. (b) Low temperature. Expose to any temperature from 5 °F to...

  8. 49 CFR 571.218 - Standard No. 218; Motorcycle helmets.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... provide peripheral vision clearance of at least 105° to each side of the mid-sagittal plane, when the... basic plane that are within the angles of peripheral vision (see Figure 3). S5.5 Projections. A helmet... including 70 percent for a minimum of 4 hours. (b) Low temperature. Expose to any temperature from 5 °F to...

  9. Biangular Coordinates Redux: Discovering a New Kind of Geometry

    ERIC Educational Resources Information Center

    Winkel, Brian; Naylor, Michael

    2010-01-01

    Biangular coordinates specify a point on the plane by two angles giving the intersection of two rays emanating from two fixed poles. This is a dual of Cartesian coordinates wherein a point on the plane is described by two distances. Biangular coordinates, first written about in 1803 in France, were subsequently studied in Britain at the end of the…

  10. Polycrystalline Superconducting Thin Films: Texture Control and Critical Current Density

    NASA Astrophysics Data System (ADS)

    Yang, Feng

    1995-01-01

    The growth processes of polycrystalline rm YBa_2CU_3O_{7-X} (YBCO) and yttria-stabilized-zirconia (YSZ) thin films have been developed. The effectiveness of YSZ buffer layers on suppression of the reaction between YBCO thin films and metallic substrates was carefully studied. Grown on the chemically inert surfaces of YSZ buffer layers, YBCO thin films possessed good quality of c-axis alignment with the c axis parallel to the substrate normal, but without any preferred in-plane orientations. This leads to the existence of a large percentage of the high-angle grain boundaries in the YBCO films. The critical current densities (rm J_{c}'s) found in these films were much lower than those in single crystal YBCO thin films, which was the consequence of the weak -link effect of the high-angle grain boundaries in these films. It became clear that the in-plane alignment is vital for achieving high rm J_{c }s in polycrystalline YBCO thin films. To induce the in-plane alignment, ion beam-assisted deposition (IBAD) technique was integrated into the conventional pulsed laser deposition process for the growth of the YSZ buffer layers. It was demonstrated that using IBAD the in-plane orientations of the YSZ grains could be controlled within a certain range of a common direction. This ion -bombardment induced in-plane texturing was explained using the anisotropic sputtering yield theory. Our observations and analyses have provided valuable information on the optimization of the IBAD process, and shed light on the texturing mechanism in YSZ. With the in-plane aligned YSZ buffer layers, YBCO thin films grown on metallic substrates showed improved rm J_{c}s. It was found that the in-plane alignment of YSZ and that of YBCO were closely related. A direct correlation was revealed between the rm J_{c} value and the degree of the in-plane alignment for the YBCO thin films. To explain this correlation, a numerical model was applied to multi-grain superconducting paths with different textures to determine the expected rm J_{c}s. The good agreement between the experimental data and numerical results confirmed that the rm J_{c} improvement directly resulted from the reduction of the number of high-angle grain boundaries in the in-plane aligned polycrystalline YBCO thin films, and provided a guideline on the further improvement of the rm J_ {c}s of polycrystalline YBCO thin films.

  11. Assessment of suturing in the vertical plane shows the efficacy of the multi-degree-of-freedom needle driver for neonatal laparoscopy.

    PubMed

    Takazawa, Shinya; Ishimaru, Tetsuya; Fujii, Masahiro; Harada, Kanako; Sugita, Naohiko; Mitsuishi, Mamoru; Iwanaka, Tadashi

    2013-11-01

    We have developed a thin needle driver with multiple degrees-of-freedom (DOFs) for neonatal laparoscopic surgery. The tip of this needle driver has three DOFs for grasp, deflection and rotation. Our aim was to evaluate the performance of the multi-DOF needle driver in vertical plane suturing. Six pediatric surgeons performed four directional suturing tasks in the vertical plane using the multi-DOF needle driver and a conventional one. Assessed parameters were the accuracy of insertion and exit, the depth of suture, the inclination angle of the needle and the force applied on the model. In left and right direction sutures, the inclination angle of the needle with the multi-DOF needle driver was significantly smaller than that with the conventional one (p = 0.014, 0.042, respectively). In left and right direction sutures, the force for pulling the model with the multi-DOF needle driver was smaller than that with the conventional one (p = 0.036, 0.010, respectively). This study showed that multi-directional suturing on a vertical plane using the multi-DOF needle driver had better needle trajectories and was less invasive as compared to a conventional needle driver.

  12. Comparative study between 2 methods of mounting models in semiadjustable articulator for orthognathic surgery.

    PubMed

    Mayrink, Gabriela; Sawazaki, Renato; Asprino, Luciana; de Moraes, Márcio; Fernandes Moreira, Roger William

    2011-11-01

    Compare the traditional method of mounting dental casts on a semiadjustable articulator and the new method suggested by Wolford and Galiano, 1 analyzing the inclination of maxillary occlusal plane in relation to FHP. Two casts of 10 patients were obtained. One of them was used for mounting of models on a traditional articulator, by using a face bow transfer system and the other one was used to mounting models at Occlusal Plane Indicator platform (OPI), using the SAM articulator. After that, na analysis of the accuracy of mounting models was performed. The angle made by de occlusal plane and FHP on the cephalogram should be equal the angle between the occlusal plane and the upper member of the articulator. The measures were tabulated in Microsoft Excell(®) and calculated using a 1-way analysis variance. Statistically, the results did not reveal significant differences among the measures. OPI and face bow presents similar results but more studies are needed to verify its accuracy relative to the maxillary cant in OPI or develop new techniques able to solve the disadvantages of each technique. Copyright © 2011 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  13. Ankle Dorsiflexion Displacement During Landing is Associated With Initial Contact Kinematics but not Joint Displacement.

    PubMed

    Begalle, Rebecca L; Walsh, Meghan C; McGrath, Melanie L; Boling, Michelle C; Blackburn, J Troy; Padua, Darin A

    2015-08-01

    The ankle, knee, and hip joints work together in the sagittal plane to absorb landing forces. Reduced sagittal plane motion at the ankle may alter landing strategies at the knee and hip, potentially increasing injury risk; however, no studies have examined the kinematic relationships between the joints during jump landings. Healthy adults (N = 30; 15 male, 15 female) performed jump landings onto a force plate while three-dimensional kinematic data were collected. Joint displacement values were calculated during the loading phase as the difference between peak and initial contact angles. No relationship existed between ankle dorsiflexion displacement during landing and three-dimensional knee and hip displacements. However, less ankle dorsiflexion displacement was associated with landing at initial ground contact with larger hip flexion, hip internal rotation, knee flexion, knee varus, and smaller plantar flexion angles. Findings of the current study suggest that restrictions in ankle motion during landing may contribute to contacting the ground in a more flexed position but continuing through little additional motion to absorb the landing. Transverse plane hip and frontal plane knee positioning may also occur, which are known to increase the risk of lower extremity injury.

  14. The Star Wars Scroll Illusion

    PubMed Central

    2015-01-01

    The Star Wars Scroll Illusion is a dynamic version of the Leaning Tower Illusion. When two copies of a Star-Wars-like scrolling text are placed side by side (with separate vanishing points), the two scrolls appear to head in different directions even though they are physically parallel in the picture plane. Variations of the illusion are shown with one vanishing point, as well as from an inverted perspective where the scrolls appear to originate in the distance. The demos highlight the conflict between the physical lines in the picture plane and perspective interpretation: With two perspective points, the scrolling texts are parallel to each other in the picture plane but not in perspective interpretation; with one perspective point, the texts are not parallel to each other in the picture plane but are parallel to each other in perspective interpretation. The size of the effect is linearly related to the angle of rotation of the scrolls into the third dimension; the Scroll Illusion is stronger than the Leaning Tower Illusion for rotation angles between 35° and 90°. There is no effect of motion per se on the strength of the illusion. PMID:27648216

  15. EFFECT OF INTENSE FUNCTIONAL TASK TRAINING UPON TEMPORAL STRUCTURE OF VARIABILITY OF UPPER EXTREMITY POST STROKE

    PubMed Central

    Sethi, Amit; Davis, Sandra; McGuirk, Theresa; Patterson, Tara S.; Richards, Lorie G.

    2012-01-01

    Study Design Quasi-experimental design Introduction Although the effectiveness of constraint induced movement therapy (CIMT) in upper extremity (UE) rehabilitation post stroke is well known, the efficacy of CIMT to enhance the temporal structure of variability in upper extremity movement is not known. Purpose The purpose of this study was to investigate whether CIMT could enhance temporal structure of variability in upper extremity movement in individuals with chronic stroke. Methods Six participants with chronic stroke underwent CIMT for 4 hours/day for 2 weeks. Participants performed three trials of functional reach-to-grasp before and after CIMT. Temporal structure of variability was determined by calculating approximate entropy (ApEn) in shoulder, elbow and wrist flexion/extension joint angles. Results ApEn increased post CIMT, however, statistical significance was not achieved (p > 0.0167). Conclusion Future studies with larger sample size are warranted to investigate the effect of CIMT upon temporal structure of variability in UE movement. PMID:23084461

  16. Sagittal plane tilting deformity of the patellofemoral joint: a new concept in patients with chondromalacia patella.

    PubMed

    Aksahin, Ertugrul; Aktekin, Cem Nuri; Kocadal, Onur; Duran, Semra; Gunay, Cüneyd; Kaya, Defne; Hapa, Onur; Pepe, Murad

    2017-10-01

    The aims of this study were to evaluate sagittal plane alignment in patients with chondromalacia patella via magnetic resonance imaging (MRI), analyse the relationships between the location of the patellar cartilaginous lesions and sagittal alignment and finally investigate the relationships between the sagittal plane malalignment and patellofemoral loadings using by finite element analysis. Fifty-one patients who were diagnosed with isolated modified Outerbridge grade 3-4 patellar chondromalacia based on MRI evaluation and 51 control subjects were evaluated. Chondromalacia patella patients were divided into three subgroups according to the chondral lesion location as superior, middle and inferior. The patella-patellar tendon angle (P-PT) was used for evaluation of sagittal alignment of patellofemoral joint. Each subgroup was compared with control group by using P-PT angle. To investigate the biomechanical effects of sagittal plane malpositioning on patellofemoral joint, bone models were created at 30°, 60° and 90° knee flexion by using mean P-PT angles, which obtained from patients with chondromalacia patellae and control subjects. The total loading and contact area values of the patellofemoral joints were investigated by finite element analysis. The mean age of all participants was 52.9 ± 8.2 years. The mean P-PT angle was significantly lower in chondromalacia group (142.1° ± 3.6°) compared to control group (144.5° ± 5.3°) (p = 0.008). Chondral lesions were located in superior, middle and inferior zones in 16, 20 and 15 patients, respectively. The mean P-PT angles in patients with superior (141.8 ± 2.7) and inferior subgroups (139.2 ± 2.3) were significantly lower than the values in the control group (p < 0.05). The contact area values were detected higher in models with chondromalacia than in the control models at the same flexion degrees. There were increased loadings at 30° and 90° flexions in the sagittal patellar tilt models. This study revealed that sagittal plain malpositioning of the patellofemoral joint might be related to chondromalacia, especially in the presence of lesions in the upper and lower part of the patella. This condition leads to supraphysiological loadings on the patellofemoral joint. Sagittal patellar tilt should be considered in the evaluation and management of patellar cartilage defects. Taking sagittal plane malalignment into consideration in patellofemoral joint evaluation will enable us to design new physical and surgical modalities. IV.

  17. Contribution of calcaneal and leg segment rotations to ankle joint dorsiflexion in a weight-bearing task.

    PubMed

    Chizewski, Michael G; Chiu, Loren Z F

    2012-05-01

    Joint angle is the relative rotation between two segments where one is a reference and assumed to be non-moving. However, rotation of the reference segment will influence the system's spatial orientation and joint angle. The purpose of this investigation was to determine the contribution of leg and calcaneal rotations to ankle rotation in a weight-bearing task. Forty-eight individuals performed partial squats recorded using a 3D motion capture system. Markers on the calcaneus and leg were used to model leg and calcaneal segment, and ankle joint rotations. Multiple linear regression was used to determine the contribution of leg and calcaneal segment rotations to ankle joint dorsiflexion. Regression models for left (R(2)=0.97) and right (R(2)=0.97) ankle dorsiflexion were significant. Sagittal plane leg rotation had a positive influence (left: β=1.411; right: β=1.418) while sagittal plane calcaneal rotation had a negative influence (left: β=-0.573; right: β=-0.650) on ankle dorsiflexion. Sagittal plane rotations of the leg and calcaneus were positively correlated (left: r=0.84, P<0.001; right: r=0.80, P<0.001). During a partial squat, the calcaneus rotates forward. Simultaneous forward calcaneal rotation with ankle dorsiflexion reduces total ankle dorsiflexion angle. Rear foot posture is reoriented during a partial squat, allowing greater leg rotation in the sagittal plane. Segment rotations may provide greater insight into movement mechanics that cannot be explained via joint rotations alone. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Exploring the safety range via the transoral approach to the craniovertebral junction.

    PubMed

    Wang, Ying; Yang, Ming; Zhang, Hongliang; Zheng, Yuhao; Tian, Yong; Li, Youqiong

    2014-07-01

    Surgeries via the transoral approach are widely used to deal with lesions near the craniovertebral junction. For this approach, the pharyngeal tubercle is an important landmark to identify the midline. The foramen lacerum, another important anatomic area where some crucial structures pass, is close to the pharyngeal tubercle. In the current study, we measured relevant distances and angles on 120 adults without brain diseases to estimate the safety range of the transoral approach. Distances between the pharyngeal tubercle and the foramen lacerum were expressed as mean (SD) and 95% confidence interval. Angles between the straight lines, which pass through the pharyngeal tubercle and the foramen lacerum, and the sagittal plane, as well as the horizontal plane, were also presented as mean (SD) and 95% confidence interval. As regards the 95% confidence intervals of the angles and the distances, which were used to define the safety range, no differences were observed between the right side and the left side. During such surgeries, if the midline is defined as a datum line, it is less likely for surgeons to destroy adjacent structures when moving within 36.30 degrees on the sagittal plane and 45.00 degrees on the horizontal plane once they find the pharyngeal tubercle. It is also safe to move within 16.20 mm from the pharyngeal tubercle. With these data, we have successfully defined the safety range of the surgery, which may help operators choose proper instruments in surgery and avoid injuries to important structures. Moreover, operators may use these data to position the pharyngeal tubercle so as not to deviate from the midline.

  19. Longitudinal changes in knee kinematics and moments following knee arthroplasty: a systematic review.

    PubMed

    Sosdian, L; Dobson, F; Wrigley, T V; Paterson, K; Bennell, K; Dowsey, M; Choong, P; Allison, K; Hinman, R S

    2014-12-01

    Knee arthroplasty (KA) is recognized as an effective treatment of knee joint osteoarthritis and up to 90% of patients experience substantial pain relief. There has been no systematic review synthesizing the longitudinal changes in gait following KA. The aims of this systematic review were to determine the effects of KA on (i) frontal plane and (ii) sagittal plane kinematic and kinetic parameters during the stance phase of gait. MEDLINE (PubMed), CINAHL, SPORTdiscus (EBSCO), and Cochrane Library (Wiley) were searched until April 10th, 2014. 1,765 articles were identified, of which 19 studies describing 3-dimensional gait analysis pre- and post-KA were included. Study quality was evaluated by two reviewers independently using the Downs and Black checklist. Following KA, in the frontal plane, the maximum knee adduction angle and external knee adduction moment (KAM) tended to decrease. In the sagittal plane, findings suggest that the maximum knee flexion moment is increased. From the ten studies that included a healthy reference group, it was unclear whether gait variables returned to normal following KA. Overall, it appears that KA results in a decreased peak KAM and maximum knee adduction angles, an increased peak knee flexion moment and inconsistent changes in the peak knee flexion angle. Knowledge gaps remain due to methodological inconsistencies across studies, limited statistical analysis, and largely heterogeneous sample populations. More research is needed to determine whether KA restores gait patterns to normal, or if additional rehabilitation may be needed to optimize gait following surgery for osteoarthritis. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. A systematic review of the angular values obtained by computerized photogrammetry in sagittal plane: a proposal for reference values.

    PubMed

    Krawczky, Bruna; Pacheco, Antonio G; Mainenti, Míriam R M

    2014-05-01

    Reference values for postural alignment in the coronal plane, as measured by computerized photogrammetry, have been established but not for the sagittal plane. The objective of this study is to propose reference values for angular measurements used for postural analysis in the sagittal plane for healthy adults. Electronic databases (PubMed, BVS, Cochrane, Scielo, and Science Direct) were searched using the following key words: evaluation, posture, photogrammetry, and software. Articles published between 2006 and 2012 that used the PAS/SAPO (postural assessment software) were selected. Another inclusion criterion was the presentation of, at least, one of the following measurements: head horizontal alignment, pelvic horizontal alignment, hip angle, vertical alignment of the body, thoracic kyphosis, and lumbar lordosis. Angle samples of the selected articles were grouped 2 by 2 in relation to an overall average, which made possible total average, variance, and SD calculations. Six articles were included, and the following average angular values were found: 51.42° ± 4.87° (head horizontal alignment), -12.26° ± 5.81° (pelvic horizontal alignment), -6.40° ± 3.86° (hip angle), and 1.73° ± 0.94° (vertical alignment of the body). None of the articles contained the measurements for thoracic kyphosis and lumbar lordosis. The reference values can be adopted as reference for postural assessment in future researches if the same anatomical points are considered. Copyright © 2014 National University of Health Sciences. Published by Mosby, Inc. All rights reserved.

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