Outer Leg Research Articles

Real-time radiative divertor feedback control development for the NSTX-U tokamak using a vacuum ultraviolet spectrometer.

A radiative divertor technique is planned for the NSTX-U tokamak to prevent excessive erosion and thermal damage of divertor plasma-facing components in H-mode plasma discharges with auxiliary heating up to 12 MW. In the radiative (partially detached) divertor, extrinsically seeded deuterium or impurity gases are used to increase plasma volumetric power and momentum losses. A real-time feedback control of the gas seeding rate is planned for discharges of up to 5 s duration. The outer divertor leg plasma electron temperature Te estimated spectroscopically in real time will be used as a control parameter. A vacuum ultraviolet spectrometer McPherson Model 251 with a fast charged-coupled device detector is developed for temperature monitoring between 5 and 30 eV, based on the Δn = 0, 1 line intensity ratios of carbon, nitrogen, or neon ion lines in the spectral range 300-1600 Å. A collisional-radiative model-based line intensity ratio will be used for relative calibration. A real-time Te-dependent signal within a characteristic divertor detachment equilibration time of ∼10-15 ms is expected.

Electron Microscopic Alterations in Pediculus humanus capitis Exposed to Some Pediculicidal Plant Extracts.

Head lice, Pediculus humanus capitis, infestation is an important public health problem in Egypt. Inadequate application of topical pediculicides and the increasing resistance to the commonly used pediculicides made the urgent need for the development of new agents able to induce irreversible changes in the exposed lice leading to their mortality. The aim of the present work is to evaluate pediculicidal efficacy of some natural products such as olive oil, tea tree oil, lemon juice, and ivermectin separately in comparison with tetramethrin-piperonyl butoxide (licid), as a standard pediculicide commonly used in Egypt. The effects of these products were evaluated by direct observation using dissecting and scanning electron microscopes (SEM). Results showed that after 1 hr exposure time in vitro, absolute (100%) mortalities were recorded after exposure to 1% ivermectin and fresh concentrate lemon juice. The mortalities were decreased to 96.7% after exposure to tea tree oil. Very low percentage of mortality (23.3%) was recorded after 1 hr of exposure to extra virgin olive oil. On the other hand, the reference pediculicide (licid) revealed only mortality rate of 93.3%. On the contrary, no mortalities were recorded in the control group exposed to distilled water. By SEM examination, control lice preserved outer smooth architecture, eyes, antenna, respiratory spiracles, sensory hairs, and legs with hook-like claws. In contrast, dead lice which had been exposed to pediculicidal products showed damage of outer smooth architecture, sensory hairs, respiratory spiracles and/or clinching claws according to pediculicidal products used.

Experimental results of H-mode power threshold with lower hybrid wave heating on the EAST tokamak

The density roll-over dependence on H-mode power threshold is observed on EAST for the first time. In campaign 2014 and 2015 shots with a toroidal field of 2.25 T have observed roll-over dependence with lower hybrid wave as the only auxiliary heating method, while shots with a toroidal field of 1.79 T and 1.9 T exhibit linear dependence consistent with scaling law. The density of minimum power for accessing H-mode on EAST has different plasma current values of 400 kA and 500 kA, and is better described in the normalized Greenwald fraction at . The absence of in 1.7 T and 1.8 T may be attributed to the positive dependence with toroidal field. Besides, correlation analysis of H-mode power threshold and divertor geometry in scanning X-point is summarized and compared. Outer leg length (distance from X-point to outer strike point) has the highest correlation coefficient with H-mode power threshold, which explains the data scattering within the same plasma parameters. A new equation of scaling law is proposed: Neutral particles are believed to be the hidden factor in different divertor geometry, and play a negative role in L–H transition via charge exchange damping.

Relationship between lateral differences in the cross-sectional area of the psoas muscle and curve running time.

BackgroundThe aim of this study was to investigate whether lateral differences in the cross-sectional areas of the hip and thigh muscles were related to curve sprinting time.MethodsThirteen college students (10 men and 3 women; mean ± SD: age, 20.4 ± 1.7 years; height, 167.6 ± 8.9 cm; mass, 57.4 ± 5.4 kg) participated in this study. The participants were instructed to sprint along a circular track (23 m radius) in the counterclockwise and clockwise directions. Magnetic resonance imaging was used to measure the cross-sectional area of the psoas major, quadriceps femoris, and hamstring muscles. The symmetry index was used to evaluate the lateral differences in the cross-sectional area.ResultsThe lateral difference was observed in the cross-sectional area (CSA) of the thigh muscles, not in the psoas major muscle. The sprint time was not significantly different between the counterclockwise (22.15 ± 2.27 s) and clockwise (22.13 ± 2.32 s) directions. No significant correlations were found between the symmetry index of the thigh muscles and the cross-directional differences in sprint time. However, the symmetry index of the psoas major muscle correlated significantly with the cross-directional difference in sprint time (r = −0.614, P = 0.026).ConclusionsThese findings suggest that the participants in whom the cross-sectional area of the psoas major muscle of the outer leg was larger than that of the inner leg were faster in curve sprinting.

Individual muscle contributions to circular turning mechanics

Turning is an activity of daily living that involves both the acceleration of the body center-of-mass (COM) towards the center of curvature and rotation of the pelvis towards the new heading. The purpose of this study was to understand which muscles contribute to turning using experimentation, musculoskeletal modeling and simulation. Ten healthy adults consented to walk around a 1-m radius circular path at their self-selected walking speed and then along a straight line at the same speed. Forward dynamics simulations of the individual subjects during the turning and straight-line walking tasks were generated to identify the contributions of individual muscle groups to the body mediolateral and anterior–posterior COM acceleration impulse and to the pelvis angular acceleration impulse. The stance leg gluteus medius and ankle plantarflexor muscles and the swing leg adductor muscles were the primary contributors to redirect the body’s COM relative to straight-line walking. In some cases, contributions to mediolateral COM acceleration were modulated through changes in leg orientation rather than through changes in muscle force. While modulation of the muscle contributions generally occurred in both the inner and outer legs, greater changes were observed during inner single-leg support than during outer single-leg support. Total pelvis angular acceleration was minimal during the single-support phase, but the swing leg muscles contributed significantly to balancing the internal and external rotation of the pelvis. The understanding of which muscles contribute to turning the body during walking may help guide the development of more effective locomotor therapies for those with movement impairments.

Quantum McKay correspondence for disc invariants of toric Calabi-Yau 3-orbifolds

We announce a result on quantum McKay correspondence for disc invariants of outer legs in toric Calabi-Yau 3-orbifolds, and illustrate our method in a special example $[\mathbb C^3 /\mathbb Z_5 (1, 1, 3)]$.

Gauged Linear Sigma Model for Disc Invariants

In this paper, we find the extended charge vectors for disc invariants of outer branes in a toric Calabi–Yau 3-orbifold, and use these extended charge vectors to establish a quantum McKay correspondence for disc invariants of branes intersecting effective outer legs, and give an enumerative explanation to the integrality of open–closed mirror map in terms of Ooguri–Vafa invariants.

Kinematics of turning during walking over ground and on a rotating treadmill.

BackgroundAfter neurological injury, gait rehabilitation typically focuses on task oriented training with many repetitions of a particular movement. Modern rehabilitation devices, including treadmills, augment gait rehabilitation. However, they typically provide gait training only in the forward direction of walking, hence the mechanisms associated with changing direction during turning are not practiced. A regular treadmill extended with the addition of rotation around the vertical axis is a simple device that may enable the practice of turning during walking. The objective of this study was to investigate to what extent pelvis and torso rotations in the transversal plane, as well as stride lengths while walking on the proposed rotating treadmill, resemble those in over ground turning.MethodsTen neurologically and orthopedically intact subjects participated in the study. We recorded pelvis and torso rotations in the transversal plane and the stride lengths during over ground turning and while walking on a rotating treadmill in four experimental conditions of turning. The similarity between pelvis and torso rotations in over ground turning and pair-matching walking on the rotating treadmill was assessed using intra-class correlation coefficient (ICC - two-way mixed single measure model). Finally, left and right stride lengths in over ground turning as well as while walking on the rotating treadmill were compared using a paired t-test for each experimental condition.ResultsAn agreement analysis showed average ICC ranging between 0.9405 and 0.9806 for pelvis and torso rotation trajectories respectively, across all experimental conditions and directions of turning. The results of the paired t-tests comparing left and right stride lengths showed that the stride of the outer leg was longer than the stride of the inner leg during over ground turning as well as when walking on the rotating treadmill. In all experimental conditions these differences were statistically significant.ConclusionsIn this study we found that pelvis rotation and torso rotation are similar when turning over ground as compared to walking on a rotating treadmill. Additionally, in both modes of turning, we found that the stride length of the outer leg is significantly longer than the stride length of the inner leg.Electronic supplementary materialThe online version of this article (doi:10.1186/1743-0003-11-127) contains supplementary material, which is available to authorized users.

Neuromuscular and biomechanical strategies of turning in ambulatory individuals post-stroke.

Given that the inter-limb asymmetry and additional balance control are required for turning, stroke subjects spend more time to turn than healthy subjects. Few studies have investigated specific turning-related neuromuscular and biomechanical strategies post-stroke to clarify factors favoring or hindering turning speed toward different directions. The purpose of this study was to compare the speed and lower-limb muscular and kinematic strategies of turning between individuals with stroke and matched controls. Fifteen ambulatory individuals with chronic stroke and 15 matched healthy controls participated in this study. Turning speed during turning along a 0.8-meter radius curved path toward both sides for 5 meters was recorded. Simultaneously, kinematics and muscle activation patterns of lower extremity were measured by the joint angle and electromyography during turning. The slower speed was noted for the turning task in stroke patients when compared to controls. Individuals with stroke have insufficient muscle activation in tibialis anterior and biceps femoris of the affected inner leg, accompanied by reduced standing knee flexion, which disturb turning toward the affected side. The augmented standing knee flexion of unaffected side in stroke patients hindered the function of the outer leg while turning toward the affected side, but assisted the role of the inner leg while turning toward the unaffected side. However, the absence of difference in turning speeds toward the affected and unaffected sides may attribute to the diminished swing phase knee flexion of the affected outer leg. Our findings suggest that there are direction-related strategies in turning for stroke subjects since the inner and outer legs, respectively, have specific roles for standing support and leg swing during turning. Therefore, in addition to turning speed, kinematics and muscular components during turning toward either direction should be considered to improve turning performance as well as to prevent falls in stroke rehabilitation.

Differences in Kinematic and Electromyographic Characteristics Between Young and Older Adults During Circular Turning

Direction change while walking is a complex task of locomotor activity and is necessary during daily activities, but little is known about whether aging alters turn-related characteristics compared with straight walking. The objective of this study was to investigate the effects of aging on the biomechanical characteristics and walking velocity during circular turning. The participants included 17 healthy older adults (65–80 years old) and 16 young adults. Walking velocity, the first and second peak knee flexion, ankle plantarflexion, ankle dorsiflexion, and electromyographic amplitudes of the rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius medialis were measured during walking along a 5 m straight path and a 5 m circumference curved path with a radius of 0.8 m. The two groups made comparable decreases in turning velocity as compared with straight walking, but older adults decreased the second peak knee flexion instead of the second peak ankle plantarflexion, and the knee remained flexed during the loading response. Older people also needed higher amplitudes of the tibialis anterior in the outer leg, and biceps femoris in the inner leg, to facilitate turning, which were not seen in young adults. Moreover, older adults did not decrease amplitudes of the rectus femoris and biceps femoris in the outer leg, and tibialis anterior in the inner leg, as noted in young adults. Aging does not exert further effects on turning velocity, but older adults use different biomechanical strategies to turn.

Evaluation of an improved atomic data basis for carbon in UEDGE emission modeling for L-mode plasmas in DIII-D

New scaled carbon atomic electron-impact excitation data is utilized to evaluate comparisons between experimental measurements and fluid emission modeling of detached plasmas at DIII-D. The C I and C II modeled emission lines for 909.8 and 514.7nm were overestimated by a factor of 10–20 than observed experimentally for the inner leg, while the outer leg was within a factor of 2. Due to higher modeled emissions, a previous study using the UEDGE code predicted that a higher amount of carbon was required to achieve a detached outboard divertor plasma in L-mode at DIII-D. The line emission predicted by using the new scaled carbon data yields closer results when compared against experiment. We also compare modeling and measurements of Dα emission from neutral deuterium against predictions from newly calculated R-Matrix with pseudostates data available at the ADAS database.

Analysis and Design of Fully Integrated Planar Magnetics for Primary–Parallel Isolated Boost Converter

A highly efficient planar integrated magnetic (PIM) design approach for primary–parallel isolated boost converters is presented. All magnetic components in the converter, including two input inductors and two transformers with primary–parallel and secondary–series windings, are integrated into an E–I–E-core geometry, reducing the total ferrite volume and core loss. The transformer windings are symmetrically distributed into the outer legs of E-cores, and the inductor windings are wound on the center legs of E-cores with air gaps. Therefore, the inductor and the transformer can be operated independently. Due to the low-reluctance path provided by the shared I-core, the two input inductors can be integrated independently, and also, the two transformers can be partially coupled to each other. Detailed characteristics of the integrated structure have been studied in this paper. AC losses in the windings and the leakage inductance of the transformer are kept low by interleaving the primary and secondary turns of the transformers substantially. Because of the combination of inductors and transformers, the maximum output power capability of the fully integrated module needs to be investigated. Winding loss, core loss, and switching loss of MOSFETs are analyzed in-depth in this work as well. To verify the validity of the design approach, a 2-kW prototype converter with two primary power stages is implemented for fuel-cell-fed traction applications with 20–50-V input and 400-V output. An efficiency of 95.9% can be achieved during 1.5-kW nominal operating conditions. Experimental comparisons between the PIM module and three separated cases have illustrated that the PIM module has advantages of lower footprint and higher efficiencies.

Probiont niche specialization contributes to additive protection against Vibrio owensii in spiny lobster larvae

The development of efficient probiotic application protocols for use in marine larviculture relies on comprehensive understanding of pathogen-probiont-host interactions. The probiont combination of Pseudoalteromonas sp. PP107 and Vibrio sp. PP05 provides additive protection against vectored Vibrio owensii DY05 infection in larvae (phyllosomas) of ornate spiny lobster, Panulirus ornatus. Here, fluorescently tagged strains were used to demonstrate niche specialization of these probionts in both the live feed vector organism Artemia and in phyllosomas. The pathogen was vulnerable to direct interaction with PP05 in the bacterioplankton as well as in the Artemia gut and the phyllosoma foregut and midgut gland. In contrast, PP107 was localized on external surfaces of Artemia and phyllosomas, and direct interaction with the pathogen was limited to the bacterioplankton. While PP107 was the overall dominant ectobiont on the phyllosoma cephalothorax and inner leg segments, PP05 was the primary colonizer of outer leg segments, nutrient-rich locales that may promote ingestion during feeding. This study shows that niche specialization can contribute to the additive probiotic effect of a probiotic mixture and highlights that probiotic enrichment of Artemia cultures can intercept the infection cycle of V. owensii DY05 in early-stage P. ornatus phyllosomas.

H-mode power threshold reduction in a slot-divertor configuration on the Alcator C-Mod tokamak

H-mode power thresholds (Pth) are examined in Alcator C-Mod lower single null plasmas with standard vertical-plate and slot-type divertor configuration (BT = 5.4 T, Ip = 0.9 MA, q95 ∼ 4.0 and 〈ne〉 = (1.3–1.6) × 1020 m−3). The required power to access H-mode is found to be significantly reduced when the plasma is operated with a slot divertor. The lowest Pth achieved is ∼0.7 MW, about 1/3 of the normal level and 40% of the multi-machine scaling law prediction. Pth does not explicitly correlate with plasma shaping parameters (X-point locations, elongation, triangularities, etc), but somehow shows an overall inverse correlation with outer divertor leg length (the poloidal distance between X-point and outer strike point) and/or the outer divertor connection length. This implies that another, still unknown parameter hidden in the vicinity of the separatrix outer leg might be responsible for the observed difference in H-mode access power. Despite the large differences in Pth, the edge electron temperature (Te) and density (ne) profiles prior to L–H transition are not strongly affected by the divertor configuration. Values of Te,95 (i.e. Te at 95% normalized poloidal flux surface) at the L–H transition are similar for the two divertor configurations.

JT-60SA TF Magnet Joints Developments and Prequalification

In the framework of the so-called “broader approach” in connection with the International Thermonuclear Experimental Reactor ITER, the European and Japanese part- ners have agreed to in kind contribute to the construction of the JT-60SA tokamak in Naka (Japan). JT-60SA is a major upgrade of the former tokamak JT-60U, equipped with, in particular, superconducting coils. France and Italy, as European Voluntary Contributors, are sharing the supply of the 18 superconducting Toroidal Field coils, along with the corresponding mechanical structures and supports. These D shaped coils use a NbTi Cable-In-Conduit Conductor (CICC) and are electrically connected in series. Each coil is composed of double pancakes connected in series and two coil terminals, all located in a joint area at their outer radius at the upper part of the outer leg. The joints proposed by CEA is the twin box design which was initially developed by CEA for ITER Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn conductors and which is now adapted to the NbTi conductor. This design relies on the use of copper/steel explosion bonded plate as base material to constitute each conductor termination, the joint being assembled by soldering of the adjacent terminations. Such a design was successfully qualified on a pre-prototype sample in the CRPP SULTAN facility. To simplify the inner joints regarding the winding pack manufacture process, an evolution towards a monobloc twin box concept is proposed. After production and qualification of the needed prototype steel/copper/steel 3-layer explosion bonded plate, a dedicated joint mock-up was used to define the corresponding manufacture process. Specific processes were also developed for the coil terminals which have to be connected in a dismountable way for the cold acceptance tests of the coils in Europe, as well as in a definitive way at the Japan site. A low cost dedicated facility was developed to measure the DC resistance in order to perform a simple prequalification in cryogenic conditions on the produced mock-ups. A benchmark of the facility using the previously prequalified sample was done to validate this facility as a simple tool usable for this resistance measurement. The paper reports the different joint proposals and the manufacture processes developed as well as the pre-qualification results.

Three-Dimensional Knee Joint Loading in Alpine Skiing: A Comparison Between a Carved and a Skidded Turn

Limited data exists on knee biomechanics in alpine ski turns despite the high rate of injuries associated with this maneuver. The purpose of the current study was to compare knee joint loading between a carved and a skidded ski turn and between the inner and outer leg. Kinetic data were collected using Kistler mobile force plates. Kinematic data were collected with five synchronized, panning, tilting, and zooming cameras. Inertial properties of the segments were calculated using an extended version of the Yeadon model. Knee joint forces and moments were calculated using inverse dynamics analysis. The obtained results indicate that knee joint loading in carving is not consistently greater than knee joint loading in skidding. In addition, knee joint loading at the outer leg is not always greater than at the inner leg. Differentiation is required between forces and moments, the direction of the forces and moments, and the phase of the turn that is considered. Even though the authors believe that the analyzed turns are representative, results have to be interpreted with caution due to the small sample size.

Neuromuscular strategies in the paretic leg during curved walking in individuals post-stroke

Reduced flexibility over the neuromotor control of paretic leg muscles may impact the extent to which individuals post-stroke modulate their muscle activity patterns to walk along curved paths. The purpose of this study was to compare lower-limb movements and neuromuscular strategies in the paretic leg of individuals with stroke with age-matched controls during curved walking. Participants walked at their preferred walking velocity along four different paths of increasing curvature, while lower-limb kinematics and muscle activity were recorded. A second group of able-bodied individuals walked along the four paths, matching the walking speed of the stroke group. The stroke group showed reduced lower-limb joint excursion and disordered modulation of foot pressure during curved walking, accompanied by reduced modulation of muscle activity patterns. In the inner leg of the curve in control subjects, the posteromedial muscles (medial gastrocnemius and medial hamstrings) showed decreased electromyographic amplitude as path curviture increased. Conversely, activity of the posterolateral musculature of the outer leg was decreased with increasing path curvature. Activity in the tibialis anterior and gluteus medius was also modulated with path curvature. However, in the stroke group, we found reduced modulation of muscle activity in the paretic leg during curved walking. The extent of modulation was also associated with the level of physical impairment due to stroke. The results of this study provide further knowledge about neuromuscular control of locomotor adaptations post-stroke.

MAST upgrade closed pumped divertor design and analysis

The design of the Mega Amp Spherical Tokamak (MAST) Upgrade project provides an excellent opportunity for advancements in tokamak physics in support of ITER and DEMO as well as CTF. One of the main areas of contribution is the divertor. MAST Upgrade will be capable of operating with the outer leg of the divertor being either conventional or with the novel Super-X Divertor (SXD) configuration, in which additional shaping of the magnetic field takes the divertor leg out to large radius. A region of low poloidal field in the chamber of the divertor allows the outer leg to traverse a considerable distance toroidally, reaching a large major radius. Cryopumps outboard the divertor targets will provide density control. This paper describes the current design and layout of the closed pumped divertor geometry to meet the configurations envisaged. The assembly supports symmetrical plasmas with both the upper and lower divertor assemblies able to accommodate either the conventional or SXD.

2A2-Q10 歩行時の状態量が測定可能な受動的動歩行ロボットの開発 : 実験による歩行動作の安定解析(受動歩行ロボット)

In this paper we propose a compass type passive dynamic walking robot which has sensors to measure its dynamical parameters to analyze its walking gaits and behavior. A typical compass type walking robot has a difficulty to keep on walking because of its structure; the outer leg and the inner leg have same length, so the swing leg strikes its foot to the ground during its walking. To improve the problem we develop a new mechanism which expand and contract the second thigh part of the legs, and contribute to cut off the impact shock of ground contact. And then we investigate the behavior of Passive Dynamic Walking by the logged data of the robot.

Fatigue fracture of the Björk–Shiley heart valve strut and failure diagnosis from acoustic signatures

Repeated loading of the outer strut leg of the Björk–Shiley 60° convexo-concave (BSCC) valve results in fatigue crack propagation, with a duration from a few months to a few years. Sound and vibration analysis emitted from the strut of the BSCC valve due to impact is used to monitor the propagation of the fatigue crack before it would lead to the failure of one or both legs of the outlet strut. Analytical and experimental results established that the range of the fundamental natural frequency is 4000–8000 Hz. Analysis of sound emitted from the strut of the valve due to impact may be used to monitor the propagation of the fatigue crack before it would lead to the failure of the one or both legs of the outlet strut.