Journal articles on the topic 'Phase angle'
To see the other types of publications on this topic, follow the link: Phase angle.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Phase angle.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Tatchev, Dragomir. "Multiphase approximation for small-angle scattering." Journal of Applied Crystallography 43, no. 1 (December 9, 2009): 8–11. http://dx.doi.org/10.1107/s0021889809048675.
Full textAbstract:
The two-phase approximation in small-angle scattering is well known and is still the dominant approach to data analysis. The intensity scattered at small angles is proportional to the second power of the difference between the scattering densities of the two phases. Nevertheless, scattering contrast variation techniques are widely used, and they are obviously suitable for multiphase systems or systems with gradually varying scattering density, since if no parasitic scattering contributions are present the scattering contrast variation would only change a proportionality coefficient. It is shown here that the scattered intensity at small angles of a multiphase system can be represented as a sum of the scattering of two-phase systems and terms describing interference between all pairs of phases. Extracting two-phase scattering patterns from multiphase samples by contrast variation is possible. These two-phase patterns can be treated with the usual small-angle scattering formalism. The case of gradually varying scattering density is also discussed.
2
Ohira, Takashi. "Phase Angle [Enigmas, etc.]." IEEE Microwave Magazine 22, no. 9 (September 2021): 101–2. http://dx.doi.org/10.1109/mmm.2021.3086379.
Full text
3
Mitrovi, Zoran. "A phase angle standard." Measurement Science and Technology 15, no. 3 (February 9, 2004): 559–64. http://dx.doi.org/10.1088/0957-0233/15/3/008.
Full text
4
Mytsenko, I., and O. Roenko. "QUICK-ACTING, CONTROLLABLE PHASE SHIFTER FOR PHASE ANGLE ADJUSTMENT IN RADIO SIGNALS." RADIO PHYSICS AND RADIO ASTRONOMY 27, no. 3 (2022): 213–18. http://dx.doi.org/10.15407/rpra27.03.213.
Full textAbstract:
Subject and Purpose. The phase shifters intended for controlling the phase of radio signals are widely used in ultra-high frequency technology, communication systems, radar, and a variety of measuring and special-purpose radio equipment. Designers of phased array antennas face the need of providing for broad beam scanning angles and high antenna gains, which leads to the necessity of greatly increasing the number of array elements, each of which is to be controlled by a phase shifter. Therefore, the development and creation of quick-acting phase shifters is an urgent task. The purpose of this work is to develop high-speed, controllable phase shifters for performing phase angle adjustments and thus provide, at an acceptable cost, for desirable parameters of phased antenna arrays, frequency stabilizing systems of magnetrons, etc. Methods and Methodology. The functional diagram of the proposed quick-acting, controllable phase shifter has been analyzed mathematically and modelled numerically. Results. The controllable phase shifter can be successfully implemented through the use of two parallel-connected resonators at the input of a specific receiver. Analysis of the signal amplitude and phase at the output of the phase shifter in dependence on the values at the input confirms the possibility of adjusting the phase of the output signal over a wide range of angles. Conclusions. A design concept of quick-acting, controllable phase shifters for producing adjustable phase angles has been developed. The device can be employed in phased antenna arrays or frequency stabilizing systems as a means of improving their operation parameters and reducing their cost at that.
5
Matsuzawa, Yuta, Takasuke Miyazaki, Yasufumi Takeshita, Naoto Higashi, Hiroyuki Hayashi, Sota Araki, Shintaro Nakatsuji, Seiji Fukunaga, Masayuki Kawada, and Ryoji Kiyama. "Effect of Leg Extension Angle on Knee Flexion Angle during Swing Phase in Post-Stroke Gait." Medicina 57, no. 11 (November 9, 2021): 1222. http://dx.doi.org/10.3390/medicina57111222.
Full textAbstract:
Background and Objectives: Leg extension angle is important for increasing the propulsion force during gait and is a meaningful indicator for evaluating gait quality in stroke patients. Although leg extension angle during late stance might potentially also affect lower limb kinematics during the swing phase, the relationship between these two remains unclear. This study aimed to investigate the relationship between leg extension angle and knee flexion angle during pre-swing and swing phase in post-stroke gait. Materials and Methods: Twenty-nine stroke patients walked along a 16 m walkway at a self-selected speed. Tilt angles and acceleration of pelvis and paretic lower limb segments were measured using inertial measurement units. Leg extension angle, consisting of a line connecting the hip joint with the ankle joint, hip and knee angles, and increments of velocity during pre-swing and swing phase were calculated. Correlation analysis was conducted to examine the relationships between these parameters. Partial correlation analysis adjusted by the Fugl-Meyer assessment-lower limb (FMA-LL) was also performed. Results: On the paretic side, leg extension angle was positively correlated with knee flexion angle during the swing phase (r = 0.721, p < 0.001) and knee flexion angle and increments of velocity during the pre-swing phase (r = 0.740–0.846, p < 0.001). Partial correlation analysis adjusted by the FMA-LL showed significant correlation between leg extension angle and knee flexion angle during the swing phase (r = 0.602, p = 0.001) and knee flexion angle and increments of velocity during the pre-swing phase (r = 0.655–0.886, p < 0.001). Conclusions: Leg extension angle affected kinematics during the swing phase in post-stroke gait regardless of the severity of paralysis, and was similar during the pre-swing phase. These results would guide the development of effective gait training programs that enable a safe and efficient gait for stroke patients.
6
Fischer, I. S., and R. N. Paul. "Kinematic Displacement Analysis of a Double-Cardan-Joint Driveline." Journal of Mechanical Design 113, no. 3 (September 1, 1991): 263–71. http://dx.doi.org/10.1115/1.2912778.
Full textAbstract:
The input-output displacement relations of two Cardan joints arranged in series on a driveline has been investigated in detail, including the effects of unequal joint angles, the phase angle between the two Cardan joints and also such manufacturing tolerance errors as nonright angle moving link lengths and offset joint axes. A combined Newton-Raphson method and Davidon-Fletcher-Powell optimization algorithm using dual-number coordinate-transformation matrices was employed to perform the analysis. An experiment was conducted to validate the results of the analysis. The apparatus consisted of a double-Cardan-joint driveline whose rotations were measured by optical shaft encoders that were sampled by a computer data-acquisition system. The equipment was arranged so that the phase angle between the joints and the offset angles between the shafts at each of the two joints could be readily varied. The “relative phase angle,” the difference between the phase angle of the two joints and the angle between the planes defined by the input and intermediate and the intermediate and output shafts, was found to be the significant factor. If the offset angles at both Cardan joints are equal, the double-Cardan-joint driveline functions as a constant-velocity coupling when the magnitude of the relative phase angle is zero. If the offset angles at the two Cardan joints are unequal, a condition prevailing in the important front-wheel-drive automobile steering-column application, then fluctuation in output velocity for a constant input velocity is minimized although not eliminated for zero relative phase angle.
7
Xi, Zhi Jun, Gang Li, and Li Ming Lu. "Fabrication of Ultrahydrophobic ZnO by Vapor Phase Transport." Advanced Materials Research 282-283 (July 2011): 753–56. http://dx.doi.org/10.4028/www.scientific.net/amr.282-283.753.
Full textAbstract:
A ultrahydrophobic ZnO film was synthesized on the Si substrates by a novel vapor phase transport method. The surface structural properties of as-synthesized ZnO film was characterized using scanning electron micrograph (SEM). The contact angles and the rolling angles on such films were measured through an optical contact angle meter. Wettability studies revealed the films exhibited a ultrahydrophobic behaviour with a higher contact angle of 166.8°±6.8° and lower rolling angle of less than 2°-a water droplet moved easily on the surface. SEM showed that compared with pure smooth nickel surface, a lotus-like structrure with micro-nano hierarchical papillae was obviously observed on the ultrahydrophobic ZnO film surface. Such a speccial surface microstructure may result in the ultrahydrophobicity.
8
Rozhkov, V., L. Taran, D. Okun, L. Riadova, and V. Shutieiev. "Influence technique of the take-off phase on the flight phase of the hop in the female triple jump among elite athletes." Scientific Journal of National Pedagogical Dragomanov University. Series 15. Scientific and pedagogical problems of physical culture (physical culture and sports), no. 11(157) (December 1, 2022): 126–29. http://dx.doi.org/10.31392/npu-nc.series15.2022.11(157).29.
Full textAbstract:
The article discusses relationships between biomechanical parameters techniques take-off phase and flight phase of the hop among the qualified women specializing in triple jump. As a result of correlation analyses was determined that if research women faster put leg on the support, they will have more initial velocity of the total center of mass of the bodies r=0,955, reducing values dilution of the hips during flight phase of the hop r=-0,773, decrease time of flight phase of the hop r=-0,788 and increases long of the hop r=0,793.
If athletes spend more time on take-off phase, they will have more initial velocity of the total center of mass of the bodies r=0,770.
Take-off angle influences on such parameter’s techniques of flight phase of the hop as: velocity of the total center of mass of the body’s r=0,721, angle between thighs r=-0,722. The correlation coefficient showed that if research athletes have more take-off angle they will have more velocity of the total center mass of the body and less angle between thighs during flight phase of the hop.
Determined direct correlation between angle between hop at the take-off phase and angle between hop at the flight phase of the hop r=0,717. If women athletes have more angles between thighs at the take-off phase, they will have more angles between thighs at flight phase of the hop.
Determined that for effective implementation phase of the hop during techniques trainings should more time spend on improvement angles parameters of the take-off, increase the velocity of the put leg on support, and less time of the take-off phase.
9
Ibrahim, M. A., and F. P. Stacom. "Phase angle regulating transformer protection." IEEE Transactions on Power Delivery 9, no. 1 (1994): 394–404. http://dx.doi.org/10.1109/61.277711.
Full text
10
Alturaigi, M. A. "Real-time phase-angle measurement." Canadian Journal of Electrical and Computer Engineering 21, no. 2 (April 1996): 57–60. http://dx.doi.org/10.1109/cjece.1996.7102126.
Full text
11
Dillenz, A., T. Zweschper, G. Riegert, and G. Busse. "Progress in phase angle thermography." Review of Scientific Instruments 74, no. 1 (January 2003): 417–19. http://dx.doi.org/10.1063/1.1524010.
Full text
12
Ozawa, Akira. "Phase angle analysis of single-phase induction motor." Electrical Engineering in Japan 106, no. 6 (1986): 59–66. http://dx.doi.org/10.1002/eej.4391060607.
Full text
13
Naidu, P. Vasudeva, M. Bindu Priya, and K. Gokul Sai Krishna. "Optimization of Phase jump angle of Series Active Power Filter (SAPF)." International Journal of Engineering Research 3, no. 9 (September 1, 2014): 526–30. http://dx.doi.org/10.17950/ijer/v3s9/902.
Full text
14
Garvey, Christopher J., Ian H. Parker, Robert B. Knott, and George P. Simon. "Small angle scattering in the Porod region from hydrated paper sheets at varying humidities." Holzforschung 58, no. 5 (August 1, 2004): 473–79. http://dx.doi.org/10.1515/hf.2004.071.
Full textAbstract:
Abstract The microscopic changes in the structure of paper at different equilibrium moisture contents were examined using the novel technique of contrast variation small angle neutron scattering (SANS). Contrast variation, by appropriate selection of the H2O:D2O ratio, was used to simplify the scattering from hydrated paper to a two-phase approximation. The two phases were paper polymers (cellulose, lignin and hemicelluloses) and a phase consisting of water and voids. The two-phase approximation is justified by consideration of the chemistry and density of each of the polymer species belonging to paper, and by matching the scattering length density of the sorbed moisture to air. The neutron intensity at the higher scattering angles examined was successfully fitted using the Porod law, which is applicable to scattering from a two-phase system at the high scattering angle limit. This limit is related to the specific surface area between the two phases. The limiting scattered intensity of neutrons was found to increase with increasing moisture content for a range of paper materials. It is concluded that the sorption of water increased the limiting intensity because water disrupted polymer-polymer bonding. The Porod law also predicts the slope of the intensity/scattering angle curve at the high scattering angle limit.
15
de Parscau, J. "Relationship between phase velocities and polarization in transversely isotropic media." GEOPHYSICS 56, no. 10 (October 1991): 1578–83. http://dx.doi.org/10.1190/1.1442968.
Full textAbstract:
Most techniques used to estimate anisotropy from multiple‐source offset VSP data assume angles measured from particle motion as an incidence angle. However, the difference between P‐wave polarization and the propagation direction for an anisotropic medium can be higher than 8 degrees. This difference provides a nonnegligible error in the estimation of anisotropy parameters from phase velocities. An exact model, proposed to describe P‐ and SV‐phase velocity variations for a transversely isotropic medium (TIM), takes into account the polarization angles. This model is a function of two anisotropy parameters (η and τ), of the vertical P‐ and SV‐wave phase velocities and of the polarization angle γ. However, η and τ can be used to express the polarization angle equation in a much simpler way. To quantify the error in estimated anisotropy parameters due to the assumption that the polarization angle is equal to the incidence angle, I study five TIMs. Each medium has an anisotropy that is representative of those observed in seismic surveying. The anisotropy parameters are recovered by inverting the P‐ and SV‐wave phase velocities for different incidence angles, and these incidence angles are assumed to be equal to the corresponding polarization angles. The mean error in estimated parameters is about 10 percent. This error is about the same as the one that would be obtained for velocities with uncertainties in their measurements. Unfortunately, the inversion of phase velocities measured from a real multiple‐source offset VSP to estimate anisotropy parameters needs, for calculating the misfit function, to add both errors in velocities due to hypothesis for angles and errors in velocity measurements due to uncertainties in data. In this case an exact model eliminates errors due to the assumption for the model and provides a more accurate estimation of anisotropy parameters.
16
Zhang, Haoqiang, Shengjing Tang, Jie Guo, and Wan Zhang. "A Two-Phased Guidance Law for Impact Angle Control with Seeker’s Field-of-View Limit." International Journal of Aerospace Engineering 2018 (2018): 1–13. http://dx.doi.org/10.1155/2018/7403639.
Full textAbstract:
A two-phased guidance problem with terminal impact angle constraints and seeker’s field-of-view limit is addressed in this paper for a missile against a nonmaneuvering incoming target. From the conventional PN guidance without any constraints, it is found that satisfying the impact angle constraint causes a more curved missile trajectory requiring a large look angle. To avoid the look angle exceeding the seeker’s physical limit, a two-phased look angle control guidance scheme with the terminal constraint is introduced. The PN-typed guidance law is designed for each guidance phase with a specific switching condition of line-of-sight. The proposed guidance law is comprised of two types of acceleration commands: the one in the initial phase which aims at controlling the missile’s look angle to reach the limit and the other for final phase which is produced by switching the navigation gain. The monotonicity of the line-of-sight angle and look angle is analyzed and proved to support the proposed method. To evaluate the specific navigation gains for both initial and final phases, the scaling coefficient between them is discussed by solving a quadratic equation with respect to the initial navigation gain. To avoid a great abrupt acceleration change at the switching instant, a minimum coefficient is chosen. Extensive simulations are performed to validate the efficiency of the proposed approach.
17
Mu, Xue Jie, Xing Wei Li, and Na Duan. "Dynamic Simulation and Analysis of Different Phase Synchronous Rotor Mixing Process." Key Engineering Materials 561 (July 2013): 279–84. http://dx.doi.org/10.4028/www.scientific.net/kem.561.279.
Full textAbstract:
Contrast and analysis of the influence that synchronous rotor mixer’s two phase angles 90° and 180° to the mixing effect using special visco-elasticity fluid software--Polyflow. The results show that 90° phase angle rotor could promote compound mixing, and improve mixing rubber’s uniformity, and its mixing effect is better than synchronous rotor with 180° phase angle.
18
White, Darris L., and Walt D. Musial. "The Effect of Load Phase Angle on Wind Turbine Blade Fatigue Damage." Journal of Solar Energy Engineering 126, no. 4 (November 1, 2004): 1050–59. http://dx.doi.org/10.1115/1.1800533.
Full textAbstract:
This paper examines the importance of load phase angle variations on fatigue damage and evaluates the potential effects of varying the load phase angle during dual-axis constant amplitude fatigue testing. The scope of this paper is limited to results from simulated wind and dynamic loads. The operating loads on a generic three bladed up-wind 1.5 MW wind turbine blade were analyzed over a range of operating conditions, and an aggregate probability distribution for the actual phase angles between the peak in-plane (lead-lag) and peak out-of-plane (flap) loads was determined. Using a finite element model (FEM) of the 1.5 MW blade and Miner’s Rule [Miner, A., 1945, “Cumulative Damage in Fatigue,” Trans. ASME, 67], the accumulated theoretical fatigue damage (based on axial strains) resulting from a fatigue test with variable phase angles using the aggregate distribution was compared to the damage resulting from a fatigue test with a constant phase angle. The FEM nodal damage distribution at specific blade cross sections were compared for the constant and variable phase angle cases. Single-node stress concentrations were distributed arbitrarily around one cross section to simulate material defects in a blade undergoing testing. Results show that the variable phase angle case results in higher damage on the critical nodes. In addition, the probability of discovering a material defect during a test was substantially increased when variable phase loading was used. The effect of phase angle sequence on the damage accumulation was also considered. For this analysis, the finite element results were processed using a nonlinear damage accumulation model. Results show that the sequence of the phase angle can have a large effect on the fatigue damage, and multiple, shorter length sequences produce higher damage than a single, long term sequence.
19
Lin, Xiao. "Cyclic Deformation Behavior and Dislocation Substructures of Hexagonal Zircaloy-4 Under Out-of-Phase Loading." Journal of Engineering Materials and Technology 122, no. 1 (August 2, 1999): 42–48. http://dx.doi.org/10.1115/1.482763.
Full textAbstract:
Macroscopic response and microscopic dislocation structures of Zr-4 subjected to biaxial fatigue under different phase angles of 30°, 60°, 90° and different equivalent strain ranges of 0.8%, 0.6%, 0.4% were studied. The testing results show that the delay angle between the stress deviators and strain increment tensors is strongly dependent on phase angle and the equivalent strain range. When phase angle equals 60°, the delay angle has the minimum variation range for all specimens. The mean value of the delay angle decreases with increasing phase angle or the equivalent strain range. The variation range and average value of the Mises equivalent stress have the maximum in S3 with the phase angle of 90°. They decrease as the equivalent strain range decreases. Zr-4 displays a pronounced initial hardening followed by a continuous softening for all specimens during out-of-phase cycling. The stabilized saturation stresses of Zr-4 under out-of-phase cycling are much higher than that under uniaxial cycling. It indicates that Zr-4 displays an obvious additional hardening. As the phase angle increases, the typical dislocation structure changes from dislocation cells to tangles. The dislocation-dislocation interactions increase resulting in an additional hardening. In essence, the degree of additional hardening depends, among other factors, on the maximum shear stress ratio of resolved shear stresses and critical resolved shear stresses (RSS/CRSS). [S0094-4289(00)00601-0]
20
Chung, Young Jin, Gi Hun Lee, and Hyeon Gyu Beom. "Atomistic Insights into the Phase Transformation of Single-Crystal Silicon during Nanoindentation." Nanomaterials 12, no. 12 (June 16, 2022): 2071. http://dx.doi.org/10.3390/nano12122071.
Full textAbstract:
The influence of the indenter angle on the deformation mechanisms of single-crystal Si was analyzed via molecular dynamics simulations of the nanoindentation process. Three different types of diamond conical indenters with semi-angles of 45°, 60°, and 70° were used. The load–indentation depth curves were obtained by varying the indenter angles, and the structural phase transformations of single-crystal Si were observed from an atomistic view. In addition, the hardness and elastic modulus with varying indenter angles were evaluated based on the Oliver–Pharr method and Sneddon’s solution. The simulation results showed that the indenter angle had a significant effect on the load–indentation depth curves, which resulted from the strong dependence of the elastic and plastic deformation ratios on the indenter angle during indentations.
21
Pan, Junxing, Jin Sun, and Xiao-Gang He. "𝜃23 = π/4 and δ = −π/2 in neutrino mixing, which convention?" International Journal of Modern Physics A 34, no. 35 (December 20, 2019): 1950235. http://dx.doi.org/10.1142/s0217751x1950235x.
Full textAbstract:
Considerable information has been obtained about neutrino mixing matrix. Present data show that in the particle data group (PDG) parametrization, the 2–3 mixing angle and the CP violating phase are consistent with [Formula: see text] and [Formula: see text], respectively. A lot of efforts have been devoted to constructing models in realizing a mixing matrix with these values. However, the particular angles and phase are parametrization convention dependent. The meaning about the specific values for mixing angle and phase needs to be clarified. Using the well-known nine independent ways of parametrizing the mixing matrix, we show in detail how the mixing angles and phase change with conventions even with the 2–3 mixing angle to be [Formula: see text] and the CP violating phase to be [Formula: see text]. The original Kobayashi–Maskawa and an additional one belong to such a category. The other 6 parametrizations have mixing angles and phase very different values from those in the PDG parametrization although the physical effects are the same. Therefore one should give the specific parametrization convention when making statements about values for mixing angles and phase.
22
Zawawi, M. N. M., Z. M. Isa, M. H. Arshad, B. Ismail, and M. H. N. Talib. "Comparative Study of Multiphase 5-Level Cascaded H-Bridge Multilevel Inverter System." Journal of Physics: Conference Series 2312, no. 1 (August 1, 2022): 012062. http://dx.doi.org/10.1088/1742-6596/2312/1/012062.
Full textAbstract:
Abstract In terms of cost and structural design, the cascaded H-bridge multilevel inverter (CHBMLI) has a significant advantage over diode clamped and capacitor clamped multilevel inverters. The total harmonic distortion (THD) of a 5-level CHBMLI system for three different phases (single-phase, three-phase, and six-phase system) is studied and compared in this work. As switching angles play a role in lowering THD, the switching angles for a 5-level CHBMLI are evaluated using four specific switching angle methods in the initial section of this paper. In the simulation of single-phase system, these angles are being utilized. The angles with the lowest THD value are chosen for three-phase and six-phase system simulation. Based on the findings, the higher phase of 5-level CHBMLI is more efficient in decreasing harmonics.
23
Zhu, Yaguang, and Tong Guo. "Galloping Trajectory Generation of a Legged Transport Robot Based on Energy Consumption Optimization." Journal of Robotics 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/9645730.
Full textAbstract:
Legged walking robots have very strong operation ability in the complex surface and they are very suitable for transportation of tools, materials, and equipment in unstructured environment. Aiming at the problems of energy consumption of legged transport robot during the fast moving, a method of galloping trajectory planning based on energy consumption optimization is proposed. By establishing transition angle polynomials of flight phase, lift-off phase, and stance phase and constraint condition between each state phase, the locomotion equations of the ellipse trajectory are derived. The transition angle of each state phase is introduced into the system energy consumption equations, and the energy optimization index based on transition angles is established. Inverse kinematics solution and trajectory planning in one gait cycle are applied to genetic algorithm process to solve the nonlinear programming problem. The results show that the optimized distribution of transition angles of state phases is more reasonable, and joint torques and system energy consumption are reduced effectively. Thus, the method mentioned above has a great significance to realize fast operation outdoors of transport robot.
24
Visvanathan, N., Z. Meglick, and D. T. Wickramasinghe. "Spectropolarimetry of Comet Halley." International Astronomical Union Colloquium 126 (1991): 245–48. http://dx.doi.org/10.1017/s0252921100066872.
Full textAbstract:
AbstractSpectropolarimetric observations from 3800 to 7000 Å were obtained for the nucleus of comet Halley for nine nights during 1985-86. The observations were spaced over phase angle of 2 to 66 °. The continuum polarization without molecular-line contamination as well as the polarization of the molecular lines were evaluated. The plot of polarization versus the phase angle shows small negative polarization for angles less than 20°. The highest polarization measured for phase angle ≤ 66° is 19.6% .The lowest polarization of −2.0% has been measured at the phase angle ~ 10°. The variation of polarization with phase angle is nearly linear in the range 30 to 60° giving a slope of 0.4316% per degree. There is small dependence of polarization with the wavelength in the region 3800 to 6500Å. The polarization of the molecular bands CN, C3, C2(0,0) and C2(1,0) have also been evaluated for the spectra of 15th December 1985, 18th and 19th March 1986 and 8th April 1986.
25
Zhu, Xinfa, and George A. McMechan. "Amplitude and phase versus angle for elastic wide-angle reflections in the τ‐p domain." GEOPHYSICS 80, no. 1 (January 1, 2015): N1—N9. http://dx.doi.org/10.1190/geo2013-0191.1.
Full textAbstract:
Near- and postcritical spherical-wave reflections contain amplitude and phase variations with incident angle that are not predicted by plane-wave solutions. However, if a spherical wavefield is decomposed into plane waves by a time-intercept-slowness ([Formula: see text]) transform, then plane-wave reflection coefficients (the Zoeppritz) can be used as the basis of amplitude/phase versus angle analysis. The spherical-wave effects on reflection coefficients near the critical angle (in the time-offset domain) were decomposed by [Formula: see text] transformation into plane waves. Kinematic ray tracing linked the reflection angle at the target reflector and the apparent slowness at the surface receiver, which enabled extracting the amplitude/phase versus angle data at the reflector from the surface [Formula: see text] data. The most reliable inversion results were obtained by combining the extracted amplitudes and phases in a composite inversion for the elastic parameters below the target reflector.
26
Xia, Tao, and Yilu Liu. "Single-Phase Phase Angle Measurements in Electric Power Systems." IEEE Transactions on Power Systems 25, no. 2 (May 2010): 844–52. http://dx.doi.org/10.1109/tpwrs.2009.2031649.
Full text
27
Negussey, D., W. K. D. Wijewickreme, and Y. P. Vaid. "Constant-volume friction angle of granular materials." Canadian Geotechnical Journal 25, no. 1 (February 1, 1988): 50–55. http://dx.doi.org/10.1139/t88-006.
Full textAbstract:
The postulate that the constant-volume friction angle [Formula: see text] of a granular material is unique and a function of mineral composition is verified experimentally. Granular materials comprised of particles ranging from minerals to metals are tested in a ring shear apparatus. Test samples are subjected to large shear displacements until a constant lower bound friction angle [Formula: see text] is mobilized. Possible effects of confining pressure, initial packing density, gradation, and particle shape on the value of [Formula: see text] are investigated. Friction angles mobilized in drained shear at the instant of maximum contraction and in undrained shear at phase transformation and steady state are compared with [Formula: see text] values. The experimental results confirm a broader fundamental significance of [Formula: see text] as a material parameter in that it is a consistent minimum drained friction angle equal to friction angles mobilized at phase transformation and steady state in undrained shear. Key words: granular materials, sand, friction angles, constant volume, steady state, phase transformation state, ring shear test.
28
Chulsoo Choi, Chulsoo Choi, Sun-Je Kim Sun-Je Kim, Jeong-Geun Yun Jeong-Geun Yun, Jangwoon Sung Jangwoon Sung, Seung-Yeol Lee Seung-Yeol Lee, and Byoungho Lee Byoungho Lee. "Deflection angle switching with a metasurface based on phase-change nanorods [Invited]." Chinese Optics Letters 16, no. 5 (2018): 050009. http://dx.doi.org/10.3788/col201816.050009.
Full text
29
Kaur, Harsharan. "Matching Body Composition Confirms Decreased Phase Angle among Diabetics Compared to Controls." Journal of Advanced Research in Medicine 09, no. 3 (October 21, 2022): 1–6. http://dx.doi.org/10.24321/2349.7181.202207.
Full textAbstract:
Background: Diabetes Mellitus refers to a group of common metabolic disorders that depicts hyperglycemia. As per WHO, the number of people with diabetes rose from 108 million in 1980 to 422 million in 2014. The global prevalence of diabetes among adults over 18 years of age rose from 4.7% in 1980 to 8.5% in 2014. Simple screening can help detect diabetes early and save lives. Many studies have found decreased phase angle among diabetics than controls but since age and BMI can be the confounders, there are few studies to match these parameters to draw the right conclusions. The objective of study was to do a matched comparison of the body composition (Body Fat%, Lean Body Mass and Total Body Water, Intracellular and Extracellular Water %) and biochemical investigations of Diabetics and Non-Diabetic Controls. Methods: The study population was taken from Indira G and hi Medical College, Shimla, which is one of the Tertiary care centers of Himachal Pradesh located in North India. All patients undergoing Body Composition measurements were diagnosed as diabetics on the basis of ADA (American Diabetic Association) diagnostic criteria. 60 diabetic patients fulfilling the inclusion criteria and 60 healthy age and sex-matched controls were enrolled in this study. Results: Matched analysis was done and it was found that the Phase angle among diabetics was lower (5.6° + 0.9°) than controls (6.3° + 1.1°) and was statistically significant, p-value <0.005. A comparison of biochemical investigations shows that there was a statistically significant difference between diabetics and controls with respect to FBS, HbA1C, Cholesterol, VLDL and HDL. Conclusion: Diabetics and controls were age, Sex and BMI matched with moderate physical activity. Waist Circumference (WC) was higher in diabetics indicating central obesity. The diabetics were found to be hypertensive with poor blood sugar control and dyslipidemia. The Phase Angle was decreased in diabetics than in controls, showing the prognosis of the disease.
30
Biondi, Biondo. "Angle-domain common-image gathers from anisotropic migration." GEOPHYSICS 72, no. 2 (March 2007): S81—S91. http://dx.doi.org/10.1190/1.2430561.
Full textAbstract:
I present a general methodology for computing angle-domain common-image gathers (ADCIGs) in conjunction with anisotropic wavefield-continuation migration. The method is based on transforming the prestack image from the subsurface-offset domain to the angle domain using slant stacks. The processing sequence is the same as that for computing ADCIGs for the isotropic case, though the interpretation of the relationship between the slopes measured in the prestack image and the aperture angles is more complex. I demonstrate that the slopes measured by performing slant stacks along the subsurface-offset axis of the prestack image provide a good approximation of the phase aperture angles, and they are exactly equal to the phase aperture angles for flat reflectors in vertical transversly isotropic (VTI) media. In the general case of dipping reflectors, the angles computed using slant stacks can be easily corrected by applying the relationships that I present in this paper, and the accurate aperture angles can be determined as a function of the reflector dip and anisotropic slowness at the reflector. I derive these relationships from both plane-wave and ray viewpoints. This theoretical development links the kinematics in ADCIGs with migration-velocity errors. I apply the proposed method to compute ADCIGs from the prestack image obtained by anisotropic migration of a 2D line recorded in the Gulf of Mexico. I analyze the error introduced by neglecting the difference between the true phase aperture angle and the angle computed through slant stacks, showing that, at least for this data set, these errors are negligible and can be safely ignored. In contrast, group aperture angles can be quite different from phase aperture angles; thus, ignoring the distinction between these two angles can be detrimental to practical applications.
31
Zheng, Chen, Fan, Hu, Chen, and Pu. "Detecting the Extremely Small Angle of an Axicon by Phase-Shifting Digital Holography." Applied Sciences 9, no. 19 (September 20, 2019): 3959. http://dx.doi.org/10.3390/app9193959.
Full textAbstract:
Axicon is an optical element that can be used to produce high-quality Bessel beams efficiently. In general, the smaller the base angle of the axicon is, the longer the diffraction-free distance of the generated Bessel beam will be. Therefore, axicon with an extremely small base angle is important for the generation of Bessel beam. However, the measurement of an extremely small base angle is a challenge. Here, we applied the phase-shifting digital holography in the measurement of axicon angle. The errors of the three measured axicons with base angles of 0.5°, 1°, and 1° were 1.94%, 4.43%, and 1.63%, respectively.
32
Nikolaev, Dmitry V., and Svetlana P. Shchelykalina. "Phase angle: medical interpretations and applications." Clinical nutrition and metabolism 2, no. 1 (January 15, 2021): 23–36. http://dx.doi.org/10.17816/clinutr71646.
Full textAbstract:
Specialists are interested in using bioimpedance technology to assess the rate of metabolic processes and body composition; thus, this study aimed to determine the possibilities of the clinical application of the phase angle, which is a parameter that is specific for the bioimpedance method to obtain body composition information. In nutrition assessment, the phase angle is used as an indirect characteristic of the protein fraction of the body and the rate of metabolic processes.
In the early 2000s, low values of the phase angle in diseased catabolic orientation were shown to assess the survival rate whereas high values assess the muscular system fitness in athletes and other individuals who regularly experience physical exertion. Systematic reviews and Meta-analyzes of subsequent years have summarized the evidence based on these provisions and identified several new applications for sarcopenia, anorexia, and renal failure. Therefore, all the reviews presented in this study confirm that higher phase angle values correspond to a better state of the body and that phase angle can dynamically change in an individual patient. This feature of the parameter requires a detailed understanding of the variability of values depending on measurement conditions.
The phase angle is recognized as a convenient diagnostic tool and a convenient parameter for screening examinations. At high values, it reflects the degree of muscular system fitness, and at low values, the severity of catabolic disorders due to existing diseases or immobilization.
33
Smith, T. B., D. A. Dubin, and M. A. Hennings. "The Weyl Quantization of Phase Angle." Journal of Modern Optics 39, no. 8 (August 1992): 1603–8. http://dx.doi.org/10.1080/713823581.
Full text
34
Majkrzak, C. F., K. Krycka, S. Krueger, N. F. Berk, P. Kienzle, and B. Maranville. "Phase-sensitive small-angle neutron scattering." Journal of Applied Crystallography 47, no. 2 (March 28, 2014): 780–87. http://dx.doi.org/10.1107/s1600576714004956.
Full textAbstract:
A method is described for determining the neutron scattering length density distribution of a molecular-scale object directly from phase-sensitive small-angle neutron scattering (SANS). The structure factor amplitude is obtained through the use of a reference structure for a collection of randomly oriented, identical objects in the dilute solution limit (negligible interparticle correlations). This work extends some of the techniques developed in recent years for phase-sensitive specular neutron reflectometry to SANS, although the approach presented here is applicable only within the range of validity of the Born approximation. The scattering object is treated as a composite consisting of an `unknown' part of interest plus a reference component, the real-space structure of the latter being completely known. If, for example, the reference part of the object is composed of a ferromagnetic material (the magnetization of which is saturated), then polarized neutron beams can be employed to extract the information required for an unambiguous inversion of the scattering data without chemical substitution. The angular averaging over all possible relative orientations of the composite object does not result in a cancellation of the phase information since the reference and unknown parts of each object have a fixed spatial relationship. The new approach proposed here is not simply another type of isomorphic substitution, but also involves a reformulation of the underlying mathematical analysis of this particular scattering problem.
35
Mueller, K. T., E. W. Wooten, and A. Pines. "Pure-absorption-phase dynamic-angle spinning." Journal of Magnetic Resonance (1969) 92, no. 3 (May 1991): 620–27. http://dx.doi.org/10.1016/0022-2364(91)90359-2.
Full text
36
Kuś, Arkadiusz, Wojciech Krauze, and Małgorzata Kujawińska. "Active limited-angle tomographic phase microscope." Journal of Biomedical Optics 20, no. 11 (September 11, 2015): 1. http://dx.doi.org/10.1117/1.jbo.20.11.111216.
Full text
37
Yang, Yazhou, Pei Ma, Le Qiao, Hao Zhang, Weidong Jin, Te Jiang, Yang Liu, and Yongliao Zou. "Phase-angle dependence of colour ratios and potential implications for lunar remote sensing." Astronomy & Astrophysics 644 (November 26, 2020): A30. http://dx.doi.org/10.1051/0004-6361/202039385.
Full textAbstract:
Context. The colour-ratio technique has been widely used in mapping planetary surfaces, but its solar phase-angle dependence is not well understood. Understanding the phase-angle dependence of the colour ratio would enhance our abilities in interpreting planetary remote sensing data. Aims. We aim to investigate the dependence of the colour ratio indices on mineralogy, phase angle, particle size, and the degree of simulated space weathering. Methods. We measured the multi-band (i.e. 458, 633, 750, and 905 nm) and multi-angle reflectance spectra of four typical lunar-type minerals with different particle sizes using a custom multi-angular imaging device. Results. The colour ratio does have a phase-angle dependence that is more sensitive to the mineralogy and wavelength and less sensitive to particle size distribution. Conclusions. The combined analysis of the colour ratio and its phase dependence can improve efficiency in mapping the lunar surface. With a prior knowledge of the phase behaviours of colour ratios of specific lunar-type minerals, an optimised colour ratio at certain phase angles can be found to efficiently distinguish the composition of a target surface.
38
Behura, Jyoti, and Ilya Tsvankin. "Role of the inhomogeneity angle in anisotropic attenuation analysis." GEOPHYSICS 74, no. 5 (September 2009): WB177—WB191. http://dx.doi.org/10.1190/1.3148439.
Full textAbstract:
The inhomogeneity angle (the angle between the real and imaginary parts of the wave vector) is seldom taken into account in estimating attenuation coefficients from seismic data. Wave propagation through the subsurface, however, can result in relatively large inhomogeneity angles [Formula: see text], especially for models with significant attenuation contrasts across layer boundaries. Here we study the influence of the angle [Formula: see text] on phase and group attenuation in arbitrarily anisotropic media using the first-order perturbation theory verified by exact numerical modeling. Application of the spectral-ratio method to transmitted or reflected waves yields the normalized group attenuation coefficient [Formula: see text], which is responsible for amplitude decay along seismic rays. Our analytic solutions show that for a wide range of inhomogeneity angles, the coefficient [Formula: see text] is close to the normalized phase attenuation coefficient [Formula: see text] computed for [Formula: see text] [Formula: see text]. The coefficient[Formula: see text] can be inverted directly for the attenuation-anisotropy parameters, so no knowledge of the inhomogeneity angle is required for attenuation analysis of seismic data. This conclusion remains valid even for uncommonly high attenuation with the quality factor [Formula: see text] less than 10 and strong velocity and attenuation anisotropy. However, the relationship between group and phase attenuation coefficients becomes more complicated for relatively large inhomogeneity angles approaching so-called ‘‘forbidden directions.’’ We also demonstrate that the velocity function remains practically independent of attenuation for a wide range of small and moderate angles [Formula: see text]. In principle, estimation of the attenuation-anisotropy parameters from the coefficient [Formula: see text] requires computation of the phase angle, which depends on the anisotropic velocity field. For moderately anisotropic models, however, the difference between the phase and group directions should not significantly distort the results of attenuation analysis.
39
Liu, Jie, Xiang Bo Li, Jia Wang, and Shou Biao Li. "The Evaluation of Organic Coating with Artificial Defect Degradation with EIS Measurement: Phase Angle at High Frequencies." Advanced Materials Research 194-196 (February 2011): 2027–30. http://dx.doi.org/10.4028/www.scientific.net/amr.194-196.2027.
Full textAbstract:
Electrochemical impedance spectra (EIS) of two kinds of damage rate samples in natural seawater were measured and the relations between coating resistances and phase angles at high frequencies were analyzed. The results indicated that for the coating systems studied, the variation of phase angles at 14 kHz with immersion time was very close to the variation of coating resistance, hence may qualitatively reflect the coating with artificial defect degradation. This approach contains no error in calculation and the special phase angle parameters could be extracted easily from the EIS measured data. These phase angle parameters may be used as quick measurements to evaluate coating with artificial defect performance.
40
Lisovsky, A. F. "Thermodynamic interpretation of a dihedral angle in composite materials." Science of Sintering 36, no. 2 (2004): 81–86. http://dx.doi.org/10.2298/sos0402081l.
Full textAbstract:
The equilibrium between solid and 1iquid phases in sintered composite materials has been studied. It is shown that closed surfaces, which bound dispersed phases, influence the mechanical equilibrium between these phases. An expression is derived for a dihedral angle in composite materials, which includes values of surface tensions at the phase interfaces as well as parameters of a composite equilibrium structure (phase composition, particle contiguity and coefficients of a particle geometry).
41
VAHEY, DAVID W., JOHN M. CONSIDINE, and MICHAEL A. MACGREGOR. "Influence of forming conditions on fiber tilt." TAPPI Journal 12, no. 4 (May 1, 2013): 33–40. http://dx.doi.org/10.32964/tj12.4.33.
Full textAbstract:
Fiber tilt describes the projection of fiber length in the thickness direction of paper. The projection is described by the tilt angle of fibers with respect to the plane of the sheet. A simple model for fiber tilt is based on jet-to-wire velocity differential in combination with cross-flows on the wire. The tilt angle of a fiber is found to vary as the sine of its in-plane orientation angle. The phase of variation is a large multiple of the fiber-misalignment angle associated with the cross flow. The multiple can decrease from 40 to 8 as the cross-flow angle increases from 1° to 10°, showing a high degree of nonlinearity. Application of the model was demonstrated by characterizing previously published tape-peels conducted at 45° intervals on both sides of a lightweight-coated base sheet. Degree of fiber pullout, a surrogate for fiber tilt, was indicated by measuring the mean gray value of images of the tape surface against a dark background. On tape peels from each side of the sheet, gray value versus angle was well described by a sine wave, but the phase of the wave was different on each side. By comparing the phases of the sine waves with those of the model, top and bottom fiber misalignment angles were calculated. The model is most sensitive to variations in misalignment angles less than 2.5°.
42
Gorbunov, Michael E., and Gottfried Kirchengast. "Wave-optics uncertainty propagation and regression-based bias model in GNSS radio occultation bending angle retrievals." Atmospheric Measurement Techniques 11, no. 1 (January 10, 2018): 111–25. http://dx.doi.org/10.5194/amt-11-111-2018.
Full textAbstract:
Abstract. A new reference occultation processing system (rOPS) will include a Global Navigation Satellite System (GNSS) radio occultation (RO) retrieval chain with integrated uncertainty propagation. In this paper, we focus on wave-optics bending angle (BA) retrieval in the lower troposphere and introduce (1) an empirically estimated boundary layer bias (BLB) model then employed to reduce the systematic uncertainty of excess phases and bending angles in about the lowest 2 km of the troposphere and (2) the estimation of (residual) systematic uncertainties and their propagation together with random uncertainties from excess phase to bending angle profiles. Our BLB model describes the estimated bias of the excess phase transferred from the estimated bias of the bending angle, for which the model is built, informed by analyzing refractivity fluctuation statistics shown to induce such biases. The model is derived from regression analysis using a large ensemble of Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) RO observations and concurrent European Centre for Medium-Range Weather Forecasts (ECMWF) analysis fields. It is formulated in terms of predictors and adaptive functions (powers and cross products of predictors), where we use six main predictors derived from observations: impact altitude, latitude, bending angle and its standard deviation, canonical transform (CT) amplitude, and its fluctuation index. Based on an ensemble of test days, independent of the days of data used for the regression analysis to establish the BLB model, we find the model very effective for bias reduction and capable of reducing bending angle and corresponding refractivity biases by about a factor of 5. The estimated residual systematic uncertainty, after the BLB profile subtraction, is lower bounded by the uncertainty from the (indirect) use of ECMWF analysis fields but is significantly lower than the systematic uncertainty without BLB correction. The systematic and random uncertainties are propagated from excess phase to bending angle profiles, using a perturbation approach and the wave-optical method recently introduced by Gorbunov and Kirchengast (2015), starting with estimated excess phase uncertainties. The results are encouraging and this uncertainty propagation approach combined with BLB correction enables a robust reduction and quantification of the uncertainties of excess phases and bending angles in the lower troposphere.
43
Weber, R., and M. Münster. "Transient Properties of Truck Tires on Real Road Surfaces." Tire Science and Technology 15, no. 3 (July 1, 1987): 188–97. http://dx.doi.org/10.2346/1.2148789.
Full textAbstract:
Abstract The cornering, or lateral force response of heavy-duty truck tires, has been evaluated on real road surfaces at speeds of 10–60 km/h. The special mobile truck tire dynamometer has a two-test-tire carriage mounted just ahead of the rear support tires of an articulated truck (tractor) trailer. Equal slip angles may be applied simultaneously to both test tires. The frequency response was evaluated by typical phase angle methods. The phase angle (lag of lateral force behind instantaneous angle) increased with frequency (time rate of application of angle) and decreased with increasing speed.
44
Hutson, M. Shane, and Mark S. Braiman. "Direct Phase Correction of Differential FT-IR Spectra." Applied Spectroscopy 52, no. 7 (July 1998): 974–84. http://dx.doi.org/10.1366/0003702981944616.
Full textAbstract:
Step-scan transient Fourier transform infrared (FT-IR) difference spectra are often measured in an ac-coupled configuration. The resulting differential intensity spectra contain both positive and negative bands. This condition poses problems for direct phase correction by the standard Mertz and Forman methods. Restricting the calculated phase angle to the range [–π/2, π/2] was previously shown to fix some of these problems, but we show that the use of a reduced-resolution phase spectrum can produce other artifacts. The effect of reduced resolution is analyzed for a simulated noise-free spectrum and for a measured transient spectrum of a real photochemical system, bacteriorhodopsin. Examination of these results reveals that the Mertz and Mertz Signed methods can produce spectral bands of reduced magnitude and unusual band shape, with considerable amounts of intensity remaining along the imaginary axis after phase correction. However, these errors can be eliminated by self-convolution of the measured interferogram, which doubles all phase angles, prior to smoothing. This procedure removes the potential discontinuities in the phase angle due to sign changes in the differential spectrum. With bacteriorhodopsin, this doubled-angle method for direct phase correction is able to produce a transient spectrum which closely matches that produced by using a separately measured dc interferogram to calculate the phase angle.
45
Zhang, Fan, Martin Böhle, and Shouqi Yuan. "Experimental investigation on the performance of a side channel pump under gas–liquid two-phase flow operating condition." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 231, no. 7 (June 2, 2017): 645–53. http://dx.doi.org/10.1177/0957650917713090.
Full textAbstract:
Side channel pump is a kind of small volume vane pump with low flow rate but high head and most side channel pumps can transport gas–liquid two-phase flow. In order to investigate the performance of this type of pump depending on the blade suction angle under gas–liquid two-phase flow operating condition, an experimental study has been carried out. The head and efficiency curves, and the influence of blade suction angle changes on these curves for different inlet gas volume fraction states are analyzed in detail. Moreover, the gas transporting capability of the impeller with three different blade suction angles (10°, 20°, 30°) are also compared. The results show that the head and efficiency performances of the three impellers decrease a large value when the side channel pump operates with a little gas inside, and the operating range narrows as well. With the increasing of inlet gas volume fraction, the performance of the side channel pump worsens. The head and efficiency performances in the single-phase state improve by increasing the blade suction angle, but decrease by increasing the blade suction angle in the gas–liquid two-phase flow state. The maximum gas transporting capability of the impeller with a small blade suction angle is better than a large blade suction angle. Analysis on the measured data allows a better understanding of the effect of inlet gas quantity on the performance of the side channel pump with different blade suction angles, and it could supply the design reference for two-phase flow side channel pumps.
46
Shinsen, Masahiro, Mitsuaki Furui, Susumu Ikeno, and Takekazu Nagae. "Deformation Characteristics in AlphaType Brass Worked by Torsion." Materials Science Forum 654-656 (June 2010): 1251–54. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.1251.
Full textAbstract:
In present work, bar samples of pure copper and Cu-Zn alpha single phase alloys setting 20mm in diameter and 150mm in length processed by torsion in the rotation speed to 1rpm every 60° twist angles. Then, deformed samples were researched microstructure and their characteristics. Microstructures of non-deformation samples were isometric, however, deformed samples streaky. Elements of bar drawn 10×10mm mesh were developed parallelogram. It was trend angle of between stretchable direction in microstructures and torsion axis increased more torsion angles. It was coincident with between the angle and deformed direction of microstructures. Shear strain was calculated by twist angle by theoretical formula. Their value corresponded rough with measurement from mesh variation. Pure copper and Cu-Zn alpha phase alloys were similar deformation microstructure, but fracture twist angle in copper was more than Cu-Zn alloys, and it was trend fracture angle had decreased as concentration of Zn increased. This trend was difference of fracture elongation obtained in tensile test.
47
Chruściński, Dariusz. "Phase-Space Approach to Berry Phases." Open Systems & Information Dynamics 13, no. 01 (March 2006): 67–74. http://dx.doi.org/10.1007/s11080-006-7268-3.
Full textAbstract:
We propose a new formula for the adiabatic Berry phase which is based on phase-space formulation of quantum mechanics. This approach sheds a new light onto the correspondence between classical and quantum adiabatic phases — both phases are related with the averaging procedure: Hannay angle with averaging over the classical torus and Berry phase with averaging over the entire classical phase space with respect to the corresponding Wigner function.
48
Matúš, Ivan, Pavel Ružbarský, and Bibiana Vadašová. "Key Parameters Affecting Kick Start Performance in Competitive Swimming." International Journal of Environmental Research and Public Health 18, no. 22 (November 12, 2021): 11909. http://dx.doi.org/10.3390/ijerph182211909.
Full textAbstract:
The study aims to determine the contribution of kinematic parameters to time to 5 m without underwater undulating and kicking. Eighteen male competitive swimmers started from three weighted positions and set the kick plate to positions 1–5. We used SwimPro cameras and the Dartfish© software. In the on-block phase, we found significant correlations (p < 0.01) between the front ankle angle and block time. The correlations between start phases were statistically significant (p < 0.01) between block time and rear ankle angle, respectively, to time to 2 m; rear knee angle and glide time; block time and time to 5 m; time to 2 m and time to 5 m; and flight distance and glide distance. The multiple regression analysis showed that the on-block phase and flight phase parameters, respectively, contributed 64% and 65% to the time to 5 m. The key block phase parameters included block time and rear knee angle. The key flight phase parameters determining time to 5 m included take-off angle and time to 2 m. The key parameters determining the performance to 5 m during the above-water phase include rear knee angle, block time, takeoff angle, and time to 2 m.
49
David Suits, L., TC Sheahan, KT Marosi, and DR Hiltunen. "Characterization of SASW Phase Angle and Phase Velocity Measurement Uncertainty." Geotechnical Testing Journal 27, no. 2 (2004): 11433. http://dx.doi.org/10.1520/gtj11433.
Full text
50
Nakatake, Jun, Koji Totoribe, Hideki Arakawa, and Etsuo Chosa. "Exploring whole-body kinematics when eating real foods with the dominant hand in healthy adults." PLOS ONE 16, no. 10 (October 28, 2021): e0259184. http://dx.doi.org/10.1371/journal.pone.0259184.
Full textAbstract:
Despite the importance of eating movements to the rehabilitation of neurological patients, information regarding the normal kinematics of eating in a realistic setting is limited. We aimed to quantify whole-body three-dimensional kinematics among healthy individuals by assessing movement patterns in defined phases while eating real food with the dominant hand in a seated position. Our cross-sectional study included 45 healthy, right-hand dominant individuals with a mean age of 27.3 ± 5.1 years. Whole-body kinematics (joint angles of the upper limb, hip, neck, and trunk) were captured using an inertial sensor motion system. The eating motion was divided into four phases for analysis: reaching, spooning, transport, and mouth. The mean joint angles were compared among the phases with Friedman’s analysis of variance. The maximum angles through all eating phases were 129.0° of elbow flexion, 32.4° of wrist extension, 50.4° of hip flexion, 6.8° of hip abduction, and 0.2° of hip rotation. The mean shoulder, elbow, and hip joint flexion angles were largest in the mouth phase, with the smallest being the neck flexion angle. By contrast, in the spooning phase, the shoulder, elbow, and hip flexion were the smallest, with the largest being the neck flexion angle. These angles were significantly different between the mouth and spooning phases (p < 0.008, Bonferroni post hoc correction). Our results revealed that characteristic whole-body movements correspond to each phase of realistic eating in healthy individuals. This study provides useful kinematic data regarding normal eating movements, which may inform whole-body positioning and movement, improve the assessment of eating abilities in clinical settings, and provide a basis for future studies.